SYSTEMS AND METHODS FOR FORMING DISPLAYS INCLUDING RECESSED

SIDE ELECTRODES

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S.

Provisional Application Serial No. 62/741158 filed on October 4, 2018, the content ofwhich is relied upon and incorporated herein by reference in its entirety.

FIELD

[0002] Embodiments are related generally to display devices, and more particularly to displays or display tiles having recessed side electrodes.

BACKGROUND

[0003] Displays comprised of a plurality of individual display tiles are used to manufacture large displays, which are sometimes referred to as tiled displays. For example, video walls comprised of multiple display tiles are known for their high-impact engagement and stunning visuals, and are utilized in a variety of settings, including retail environments, control rooms, airports, television studios, auditoriums and stadiums. As will be apparent from Fig. 1, in current displays, the edge portions of the display tiles and the display device itself are utilized for electrical leads and various other electronic components associated with the operation of the display panel, such as driver circuits that can include thin film transistor arrays for an active matrix display. Examples of these displays include liquid crystal displays (LCD) and organic light emitting diode (OLED) displays. This has resulted in flat display panel manufacturers encasing the edge portions within and/or behind a bezel, which conceals the foregoing electronic components.

[0004] Fig. 1 shows a prior art display tile 50, which comprises a first substrate 52 having a first surface 55 and an outer perimeter 56. The display tile 50 includes rows 60 of pixel elements and columns 70 of pixel elements 58. Each row 60 of pixel elements 58 is connected by a row electrode 62 and a plurality of columns 70 of pixel elements 58, and each column 70 of pixel elements 58 is connected by a column electrode 72. The display tile further includes at least one row driver 65 that activates the rows 60 of pixel elements 58 and at least one column driver 75 that activates the columns 70 of pixel elements 58. ln the prior art display tile 50, the row drivers 65 and the column drivers 75 are located on the first surface 55 on the same side of the pixel elements, requiring a bezel (not shown) to cover the row drivers 65 and the column drivers 75.

[0005] For aesthetic reasons, flat panel display makers are trying to maximize the image viewing area and provide a more aesthetically pleasing appearance by minimizing the size of the bezel surrounding the image on the display. However, there are practical limits to this minimization, and current bezel sizes are on the order of 3 millimeters to 10 millimeters in width.

[0006] There have been efforts in the industry to achieve tiled displays comprised of display tiles with no bezel and seamless zero millimeter bezel (referred to herein as "zero bezel" or "bezel- free"). Bezel-free display tiles allow for vast configurations of tiled displays without the need for irritating black gaps. To achieve a bezel-free display tile, it can be advantageous to have the pixel elements in close proximity to the edges of the display tiles. These pixel elements can be located on the front side of the display tile substrate and the control electronics on the back side. As a result, there is a need to electrically interconnect the front and back sides of the display tile substrate.

[0007] One way to achieve such interconnects in a display tile substrate made from glass is with metallized through glass vias ("TGVs"). Such TGVs can be used to manufacture a zero bezel microLED display, however, tGVs are fairly expensive to make, at least using current methods which involve laser damage of each hole (a serial process) followed by etch. The holes then need to be further processed for metallization.

[0008] lmplementation of TGVs presents challenges with overall manufacturing process sequence lf the front of the tile substrate is to have a thin film transistor (TFT) array, a question arises as to when the glass vias are made and metallized. Since TFT array fabrication is traditionally done on a pristine glass surface, etching and metallization may best be done after TFT fabrication. As a result, the array must be protected from etch and also be compatible with the metallization technique. [0009] Hence, for at least the aforementioned reasons, there exists a need in the art for advanced systems and methods for manufacturing multi-tile displays.

SUMMARY

[0010] Embodiments are related generally to display devices, and more particularly to displays or display tiles having recessed side electrodes.

[0011] This summary provides only a general outline of some embodiments. The phrases “in one embodiment,”“according to one embodiment,” "in various embodiments", "in one or more embodiments", "in particular embodiments" and the like generally mean the particular feature, structure, or characteristic following the phrase is included in at least one embodiment, and may be included in more than one embodiment lmportantly, such phrases do not necessarily refer to the same embodiment. Many other embodiments will become more fully apparent from the following detailed description, the appended claims and the accompanying drawings.

BRJEF DESCR1PT10N OF THE F1GURES

[0012] A further understanding of the various embodiments of the present invention may be realized by reference to the figures which are described in remaining portions of the specification ln the figures, like reference numerals are used throughout several figures to refer to similar components ln some instances, a sub-label consisting of a lower case letter is associated with a reference numeral to denote one of multiple similar components. When reference is made to a reference numeral without specification to an existing sub-label, it is intended to refer to all such multiple similar components.

[0013] Fig. 1 is a schematic top perspective view of a prior art display;

[0014] Fig. 2 is a schematic top perspective view of a display tile including pixel elements on a one surface of the display tile connected using side electrodes to one or more column/row driver circuits on an opposite surface of the display tile;

[0015] Fig. 3 is a side perspective view of the display tile of Fig. 2;

[0016] Fig. 4 is a schematic bottom perspective view of the display tile of Fig.2; [0017] Fig. 5 is an end view of a flexible, adhesive side electrode that may be used in relation to some embodiments;

[0018] Fig. 6 is a top plan view of the flexible, adhesive side electrode of Fig. 5;

[0019] Fig. 7 is a side view of a straight side of a display tile including a side electrode formed of the flexible, adhesive side electrode circuit of Fig. 5 attached to the straight side;

[0020] Fig. 8 is a top plan view of the display tile of Fig. 7;

[0021] Fig. 9 is a side view of a rounded side of a display tile including a side electrode formed of the flexible, adhesive side electrode circuit of Fig. 5;

[0022] Fig. 10 is a top plan view of the display tile of Fig. 7;

[0023] Fig. 11 is top perspective view of a display including a number of display tiles spaced a sufficient distance from one another to accommodate side electrodes on respective display tiles that each exhibit either straight ends or curved ends;

[0024] Fig. 12 is a schematic top perspective view of a display tile including pixel elements on a one surface of the display tile connected using recessed side electrodes to one or more column/row driver circuits on an opposite surface of the display tile in accordance with some embodiments;

[0025] Figs. 13 -18 are top views of display tile p ortions showing various micro-trench configurations where each micro -trench is capable of holding a recessed side electrode in accordance with various embodiments;

[0026] Fig. 19 is a flow diagram showing a method for forming displays or display tiles including micro-trenches in accordance with some embodiments;

[0027] Fig. 20 shows a top view of a glass panel from which a display tile is cut in accordance with some embodiments;

[0028] Figs. 21 -22 show side views of a laser cutting process used in relation to some embodiments;

[0029] Fig. 23 shows is a top view of a display tile including micro-trenches in accordance with various embodiments; [0030] Fig. 24 is a side perspective view of a portion of the display tile of Fig. 23;

[0031] Fig. 25 is a side perspective view of a portion of the display tile of Fig. 24 covered with a masking layer that leaves micro-trench regions exposed;

[0032] Fig. 26 is a side perspective view of a portion of the display tile of Fig. 25 after formation of micro-trenches in the micro-trench regions exposed through the masking layer;

[0033] Fig. 27 is a flow diagram showing a method for forming recessed side electrodes in accordance with some embodiments;

[0034] Fig. 28 is a side perspective view of a number of display tiles stacked next to one another with at least one side of each of the display tile and at least one micro-trench on the side somewhat aligned in accordance with some embodiments;

[0035] Fig. 29 shows the stacked display tiles of Fig. 29 with a top edge surface covered with solder paste in accordance with some embodiments;

[0036] Fig. 30 shows the stacked display tiles of Fig. 29 after curing and flowing the solder paste such that each micro-trench includes a recessed side electrode in accordance with some embodiments;

[0037] Fig. 31 is a flow diagram showing another method for forming recessed side electrodes in accordance with other embodiments;

[0038] Fig. 32 shows the stacked display tiles of Fig. 29 with the aligned micro-trenches filled with a nanoparticle solution or suspension in accordance with various embodiments;

[0039] Fig. 33 shows the stacked display tiles of Fig. 29 after reduction and agglomeration of the nanoparticle solution or suspension in accordance with various embodiments;

[0040] Fig. 34 is a flow diagram showing another method for forming recessed side electrodes in accordance with other embodiments;

[0041] Fig. 35 shows the stacked display tiles of Fig. 29 after plating the inner walls of the micro-trenches in accordance with some embodiments; and [0042] Fig. 36 is the side perspective view of Fig. 24 augmented to show the portion of the display tile of Fig. 23 after formation of a side electrodes within the micro-trenches and formation of an insulator layer over the side electrodes.

DETA1LED DESCR1PT10N

[0043] Embodiments are related generally to display devices, and more particularly to displays or display tiles having recessed side electrodes.

[0044] Some embodiments provide displays and display tiles used in multi-tile displays where row drivers and column drivers are located on one surface of the display or display tile, and pixel elements are located on the opposite surface of the display or display tile. Side electrodes are formed to provide electrical coupling between electrical elements (e.g., the row driver) on one surface of the display or display tile and electrical elements (e.g., the pixel element) on the opposite surface of the display or display tile. The side electrodes are formed within recesses along the sides of the display or display tile. Such recessed side electrodes allow for an increased effective display area.

[0045] Some embodiments provide displays that include at least a first display tile and a second display tile. Each of the first display tile and the second display tile includes: a substrate, a first side electrode, and a second side electrode. The substrate includes: a first surface and a second surface, a first side extending between the first surface and the second surface along a first portion of an outer perimeter of the substrate, a second side extending between the first surface and the second surface along a second portion of the outer perimeter of the substrate, a first recessed area with an opening along the first portion of the outer perimeter, and a second recessed area with an opening along the second portion of the outer perimeter. The first side electrode is disposed within the first recessed area such that it does not extend beyond the first portion of the outer perimeter, and the second side electrode is disposed within the second recessed area such that the second side electrode does not extend beyond the second portion of the outer perimeter.

[0046] ln some instances of the aforementioned embodiments, each of the first display tile and the second display tile further includes: a first row driver disposed on or near the second surface; a pixel element disposed on or near the first surface; a first conductor extending over the first surface from the pixel element to a first end of the first side electrode; a second conductor extending over the second surface from the row driver to a second end of the first side electrode; a column driver disposed on or near the second surface; a third conductor extending over the first surface from the pixel element to a first end of the second side electrode; and a fourth conductor extending over the second surface from the column driver to a second end of the second side electrode.

[0047] Other embodiments provide display tiles that include: a substrate, a first side electrode, and a second side electrode. The substrate includes: a first surface and a second surface, a first side extending between the first surface and the second surface along a first portion of an outer perimeter of the substrate, a second side extending between the first surface and the second surface along a second portion of the outer perimeter of the substrate, a first recessed area with an opening along the first portion of the outer perimeter, and a second recessed area with an opening along the second portion of the outer perimeter. The first side electrode is disposed within the first recessed area such that it does not extend beyond the first portion of the outer perimeter, and the second side electrode is disposed within the second recessed area such that the second side electrode does not extend beyond the second portion of the outer perimeter.

[0048] ln some instances of the aforementioned embodiments, the substrate is a glass based substrate. As used herein, the phrase "glass based substrate" is used in the broadest sense to include any object made wholly or partly of glass and/or ceramic. Glass based substrates include, but are not limited to, laminates of glass and non-glass materials, laminates of glass and crystalline materials, and/or glass-ceramics (including an amorphous phase and a crystalline phase) ln some embodiments, substrates other than glass based substrates may be used including, but not limited to, polymer, polymer laminate, printed circuit board, or metal.

[0049] ln various instances of the aforementioned embodiments, the display tile further includes: a circuit disposed on or near the second surface, and an electrical element disposed on or near the first surface. As used herein, the phrase "electrical element" is used in its broadest sense to mean any device or structure capable of transferring and/or processing an electrical signal. Thus, an electrical element may be, but is not limited to, a conductor, a semiconductor, an electrode, a thin-film-transistor, a capacitor, a resistor, an inductor, a light emitting diode (hereinafter "LED"), an organic light emitting diode (hereinafter "OLED"), a liquid crystal cell, and/or an electrically controlled optical device. A first conductor extends over the first surface from the electrical element to a first end of the first side electrode, and a second conductor extends over the second surface from the circuit to a second end of the first side electrode ln some such instances, the circuit is a row driver, and the electrical element is a pixel element ln certain instances, the pixel element is a first pixel element, and the display tile includes a second pixel element disposed on or near the first surface. A third conductor may electrically couple the first pixel element to the second pixel element. The aforementioned pixel element(s) may be, but are not limited to, a light emitting diode (LED), a micro LED, a liquid crystal display (LCD) element, or an organic light emitting diode (OLED) element ln various instances of the aforementioned embodiments, the display tile further includes: a column driver disposed on or near the second surface, a third conductor extending over the first surface from the pixel element to a first end of the second side electrode; and a fourth conductor extending over the second surface from the column driver to a second end of the second side electrode ln various cases, a row driver and/or a column driver may be located on a separate circuit board and electrically connected to the electrical elements on the substrate second surface by use of a flex connector, solder connection, or other suitable method.

[0050] ln various instances of the aforementioned embodiments, the first recessed area is a first trench, and the second recessed area is a second trench. Such trenches may be, but are not limited to, a rounded side trench, a straight side trench, and/or a combination trench including both a rounded side and a straight side ln some instances of the aforementioned embodiments, the first recessed area exhibits a first shape and the second recessed area exhibits a second shape where the first shape is different from the second shape ln some such instances, the first shape is used as a registration mark. The aforementioned recesses may be formed into an edge of a substrate, into a coating formed on the edge of a substrate, or into a combination of the edge of the substrate and a coating on the edge of the substrate.

[0051] ln some instances of the aforementioned embodiments, a thickness of the first side and the second side measured as a distance along a line perpendicular to the first surface and extending between the first surface and the second surface is less than or equal to three (3) millimeters ln various instances of the aforementioned embodiments, a depth of the first recessed area measured as a distance along a line perpendicular to the first side and parallel the first surface is less than two hundred fifty (250) micrometers ln some instances of the aforementioned embodiments, a width of the opening of the first recessed area measured along a line parallel to both the first side and the first surface is less than one hundred (100) micrometers.

[0052] ln various instances of the aforementioned embodiments, the display tile further includes a third recessed area exhibiting an opening along the first portion of the outer perimeter. A separation between the third recessed area and the first recessed area measured along a line parallel to both the first side and the first surface from one side of the opening of the first recessed area to an adjacent side of the opening of the second recessed area where the one side of the opening of the first recessed area is adjacent to the one side of the opening of the second recessed area is less than two hundred fifty (250) micrometers.

[0053] ln some instances of the aforementioned embodiments, the first side electrode is formed of a conductive material. As used herein, the phrase "conductive material" is used in its broadest sense to mean any material capable of conducting electrical signals. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of conductive materials that may be used in relation to different embodiments. The conductive material may be, but is not limited to, a metal. Such a metal may be, but is not limited to, aluminum; molybdenum; indium tin oxide; palladium; titanium; tin; silver; copper; gold; multi-layer combinations of conductors; or any metal alloy containing two or more of aluminum; molybdenum; indium tin oxide; palladium; titanium; tin; silver; copper; gold ln certain instances of the aforementioned embodiments, the display tile further includes an insulator material formed over the first side electrode and the second side electrode.

[0054] Yet other embodiments provide methods of manufacturing a display. Such methods include stacking at least a first display tile and a second display tile such that at least one side of the first display tile aligns with a side of the second display tile and together the sides form a top edge surface. The at least one side of the first display tile includes a first recessed area with an opening along the at least one side of the first display tile, and the side of the second display tile includes a second recessed area with an opening along the side of the second display tile. The first recessed area is adjacent the second recessed area. The methods further include forming a conductive material within both the first recessed area and the second recessed area, wherein the conductive material does not extend onto the top edge surface ln some instances, the methods further include unstacking the first display tile from the second display tile such that the conductive material remains within each of the first recessed area and the second recessed area.

[0055] ln various instances of the aforementioned embodiments, the methods further include: electrically coupling the conductive material in the first recessed area to a driver circuit disposed on or near a first surface of a substrate of the first display tile, and electrically coupling the conductive material in the first recessed area to a pixel element disposed on or near a second surface of the substrate of the first display tile where the first surface of the first substrate is opposite the second surface of the substrate of the first display tile.

[0056] ln some instances of the aforementioned embodiments, the methods further include: forming the first recessed area in a first substrate to yield the first display tile, and forming the second recessed area in a second substrate to yield the second display tile ln some such instances, the first substrate and the second substrate are both glass based substrates ln various such instances, forming the first recessed area in the first substrate and forming the second recessed area in the second substrate includes: laser cutting the first recessed area into the first substrate; and laser cutting the second recessed area into the second substrate ln certain instances, laser cutting the first recessed area into the first substrate includes:

disposing a laser absorption material against a selected one of a first surface or a second surface of the first substrate; directing laser radiation toward the non-selected one of the first surface or the second surface of the first substrate such that the laser radiation passes through the substrate to an interface between the substrate and the laser absorption material resulting in removal of material from the substrate at regions near the interface; and moving the laser radiation along a path such that the interface moves along a similar path. Removal of material from the first substrate at regions near the interface results in formation of the first recessed area ln other such instances, forming the first recessed area in the first substrate and forming the second recessed area in the second substrate includes: applying a masking material to the stack such that an area corresponding to the first recessed area and the second recessed area remain exposed; and etching the stack to remove material from the first substrate and the second substrate at regions near the areas that remain exposed. Etching the stack may include, but is not limited to, wet chemical etching; dry chemical etching;

mechanical etching; or a combination of two or more of wet chemical etching, dry chemical etching, and/or mechanical etching. [0057] ln some instances of the aforementioned embodiments, forming the conductive material within both the first recessed area and the second recessed area includes: at least partially filling the first recessed area and the second recessed area with a solder paste; curing the solder paste leaving a conductive material derived from the solder paste in both the first recessed area and the second recessed area; and unstacking the first display tile from the second display tile such that the conductive material remains within each of the first recessed area and the second recessed area.

[0058] ln other instances of the aforementioned embodiments, forming the conductive material within both the first recessed area and the second recessed area includes: flowing the conductive material in a molten form through a channel comprised of both the first recessed area and the second recessed area; cooling the conductive material; and unstacking the first display tile from the second display tile such that the conductive material remains within each of the first recessed area and the second recessed area.

[0059] ln yet other instances of the aforementioned embodiments, forming the conductive material within both the first recessed area and the second recessed area includes: depositing a seed material within each of the first recessed area and the second recessed area; plating walls within each of the first recessed area and the second recessed area with the conductive material; and unstacking the first display tile from the second display tile such that the conductive material remains within each of the first recessed area and the second recessed area.

[0060] ln yet other instances of the aforementioned embodiments, forming the conductive material within both the first recessed area and the second recessed area includes: flowing a liquid based nanoparticle material into a channel comprised of both the first recessed area and the second recessed area; drying the liquid based nanoparticle material within the first recessed area and the second recessed area to form a nanoparticle residue along the walls of the first recessed area and the second recessed area; applying laser energy to the nanoparticle residue along the walls of the first recessed area and the second recessed area to reduce the nanoparticle residue into metal nanoparticles agglomerated into the conductive material; and unstacking the first display tile from the second display tile such that the conductive material remains within each of the first recessed area and the second recessed area. The nanoparticle residue may include nanoparticles that are, but are not limited to, copper oxide (CuO) and/or silver oxide (AgO).

[0061] Yet further embodiments provide methods of manufacturing a display. The methods include: forming a first recessed area in a substrate. The substrate includes: a first surface and a second surface, a first side extending between the first surface and the second surface along a first portion of an outer perimeter of the substrate, a second side extending between the first surface and the second surface along a second portion of the outer perimeter of the substrate, an opening of the first recessed area is along the first portion of the outer perimeter of the substrate. The first surface is opposite the second surface. The methods further include: forming a second recessed area in the substrate such that an opening of the second recessed area is along the second portion of the outer perimeter of the substrate; and forming a conductive material within each of the first recessed area and the second recessed area such that the conductive material does not extend past the outer perimeter of the substrate.

[0062] ln some instances of the aforementioned embodiments, the methods further include: electrically coupling the conductive material in the first recessed area to a first circuit disposed on or near a first surface of the substrate; electrically coupling the conductive material in the second recessed area to a second circuit disposed on or near a first surface of the substrate; electrically coupling the conductive material in the first recessed area to a pixel element disposed on or near a second surface of the substrate; and electrically coupling the conductive material in the second recessed area to the pixel element.

[0063] ln various instances of the aforementioned embodiments, forming the first recessed area in a substrate includes laser cutting the first recessed area into the first side of the substrate ln some such instances, laser cutting the first recessed area into the first side of the substrate includes: disposing a laser absorption material against one of the first surface or the second surface of the substrate; directing laser radiation toward the other of the first surface or the second surface of the substrate such that the laser radiation passes through the substrate to an interface between the substrate and the laser absorption material resulting in removal of material from the substrate at regions near the interface; and moving the laser radiation along a path such that the interface moves along a similar path. Removal of material from the substrate at regions near the interface results in formation of the first recessed area. [0064] ln other instances, forming the first recessed area in the first substrate and forming the second recessed area in the second substrate includes: applying a masking material to the stack such that an area corresponding to the first recessed area and the second recessed area remain exposed; and etching the stack to remove material from the first substrate and the second substrate at regions near the areas that remain exposed. Etching the stack may include, but is not limited to, wet chemical etching; dry chemical etching; mechanical etching; or a combination of two or more of wet chemical etching, dry chemical etching, and/or mechanical etching.

[0065] Turning to Figs. 2-4, a display tile 150 is shown, which includes a first substrate 152 comprising a first surface 155, a second surface 157 opposite the first surface 155 and an edge surface 154 between the first surface 155 and the second surface 157, the edge surface 154 defining an outer perimeter 156 of the display tile.

[0066] The display tiles 150 described herein according to one or more embodiments can comprise a substrate 152 of any suitable material, for example, a polymeric substrate, printed circuit board, metal, or a glass based substrate having any desired size and/or shape appropriate to produce a display tile. The first surface 155 and second surface 157 may, in certain embodiments, be planar or substantially planar, e.g., substantially flat. The first surface 155 and the second surface 157 may, in various embodiments, be parallel or substantially parallel. The substrate 152 according to some embodiments may comprise four edges as illustrated in Figs. 2-4, or may comprise more than four edges, e.g. a multi-sided polygon ln other embodiments, the display tile 150 may comprise less than four edges, e.g., a triangle. By way of a non-limiting example, the substrate 152 may comprise a rectangular, square, or rhomboid sheet having four edges, although other shapes and configurations are intended to fall within the scope of the disclosure including those having one or more curvilinear portions or edges.

[0067] ln certain embodiments, substrate 152 may have a thickness di of less than or equal to about 3 mm. ln some embodiments, thickness di is between 0.01 mm and three (3) mm. ln some embodiments, thickness di is between 0.1 mm and 2.5 mm. ln various embodiments, thickness di is between 0.3 mm and two (2) mm. ln some embodiments, thickness di is between 0.3 mm and two (2) mm. ln some embodiments, thickness di is between 0.3 mm and 1.5 mm. ln some embodiments, thickness di is between 0.3 mm and one (1) mm. ln some embodiments, thickness di is between 0.3 mm and 0.7 mm. ln some embodiments, thickness di is between 0.3 mm and 0.5 mm.

[0068] The glass based substrate used to manufacture the display tile can comprise any glass based material known in the art for use in display devices. For example, the glass based substrate may comprise aluminosilicate, alkali-aluminosilicate, borosilicate, alkali- borosilicate, aluminoborosilicate, alkali-aluminoborosilicate, soda lime, or other suitable glasses. Non-limiting examples of commercially available glasses suitable for use as a glass substrate include, for example, EAGLE XG®, LotusTM, and Willow®glasses from Coming lncorporated.

[0069] The first surface 155 of the display tile 150 includes an array of pixel elements 158 arranged in a plurality of rows 160 of pixel elements 158 and a plurality of columns 170 of pixel elementsl 58. Each row 160 ofpixel elements 158 is connected by a row electrode 162, and each column 170 of pixel elements 158 is connected by a column electrodel72. lt will be understood, that the rows 160 and columns 170 ofpixel elements that intersect include some of the same pixel elements 158. Thus, there are not two separate sets of pixel elements 158, but one array ofpixel elements 158 containing pixel elements 158 that are both connected to separate row and column electrodes. The display tile according to one or more embodiments includes at least one row driver 165 that electrically activates the rows 160 ofpixel elements 158 and at least one column driver 175 that activates the columns 170 ofpixel elements 158, the row drivers 165 and the column drivers 175 are located opposite the first surface 155. ln the embodiment shown in Figs. 2-4, the row drivers 165 and the column drivers 175 are located on the second surface 157 of the substrate 152. ln other embodiments, the row drivers 165 and the column drivers 175 can be located on a separate structure disposed opposite the first surface 155, such as on a separate substrate (not shown) or other suitable structure ln some such cases, electrical contacts are located opposite the substrate first surface 175 that are then electrically connected to the row and column drivers either with a flex connector, solder connection, or other suitable method. Electrically coupling from one surface to an electrical contact on the opposite surface that is ultimately connected to a row or column driver is considered electrically coupling to the row or column driver.

[0070] As will be appreciated, the row drivers 165 and the column drivers 175 are connected to the row electrodes 162 and the column electrodes 172 to activate the pixel elements 158. A plurality of row electrode connectors 164 are provided, and each row electrode connector 164 is wrapped around the edge surface 154 and electrically connects a row electrode 162, a row 160 of pixel elements 158 and a row driver 165. The display tile shown further includes a plurality of column electrode connectors 174, each column electrode connector 174 wrapped around the edge surface 154 and electrically connecting a column electrodel72, a column 170 of pixel elements 158 and the column driver 175. ln the embodiment shown, each row driver 165 is shown as connecting three rows 160 of row electrodes to pixel elements 158, and each column driver is shown as connecting four columns 170 of column electrodes 172 to pixel elements 158. lt will be understood that this arrangement is for illustration purposes only, and the disclosure is not limited to any particular number of row drivers, column drivers or number of row electrode or column electrodes respectively driven by the row drivers and column drivers. For example, the electrode connectors can exist on only one or multiple edge surfaces 154 based on the specific display design and layout. Furthermore, the disclosure is not limited to any particular number of pixel elements 158 or arrangement of pixel elements 158 on the first surface 155 of the substrate 152. Although a matrix backplane design is described, alternative configurations are also possible. The electrical backplane circuitry described with row and column matrices can either be a passive matrix or active matrix design lf active matrix, the thin film transistor array can exist either on the first, second, or both substrate surfaces. Alternatively, the display backplane can include driver or micro -driver integrated circuits (1C) directly communicating with the pixels. These driver or micro-driver lCs can be located on the first, second, or both substrate surfaces or on a separate substrate that is electrically connected to the second surface of the substrate.

[0071] Any suitable connector type can be utilized to provide the row electrode connectors 164 and the column electrode connectors 174. Also, all of the electrode connectors do not need to be of the same type or design ln one or more embodiments, at least one row electrode connector 164 and at least one column electrode connector 174 comprises a flexible, adhesive side electrode 300 as shown in Figs. 6 and 7. Flexible, adhesive side electrode 300 comprises a flexible polymeric film 302 and a conductor 304. ln the embodiment shown, a plurality of conductors 304 are shown arranged in rows. The flexible, adhesive side electrode 300 may further comprise an adhesive 306 that adheres the flexible, adhesive side electrode 300 to the edge surface 154 of the substrate 152. ln the embodiment shown, the adhesive 306 is an adhesive layer that is integrally formed with the flexible, adhesive side electrode ln some embodiments, the flexible, adhesive side electrode 300 may comprise the flexible polymeric film 302 and the conductor(s) 304, and an adhesive may be separately applied. The flex circuit 300 has a total thickness in a range of ten (10) micrometers to one hundred fifty (150) micrometers, for example, in a range of ten (10) micrometers to fifty (50) micrometers in a range of ten (10) micrometers to twenty (20) micrometers. Suitable materials for the polymeric film 302 include, but are not limited to materials selected from the group consisting of polyimide, polyester, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and polyether ether ketone (PEEK).

The adhesive 306 can comprise a pressure sensitive adhesive, for example, a pressure sensitive adhesive comprising a material selected from the group consisting of a polyimide, an acrylic, an acrylate, ethylene vinyl acetate, butyl rubber, nitrile, and silicone. The flexible, adhesive side electrode 300 can also be adhered to the edge surface 154 by use of a curable or liquid adhesive. The conductor 304can be selected from copper and silver, other metals or other conductive material capable of forming individual electrode traces, and can be formed by any suitable method such as deposition, plating, printing, etc. Examples of conductive materials not based on deposited films include Ag ink, CNT, and other solution-based materials. The overall dimension of the flex circuit can vary, and ultimately will be determined by the size of the display tile. A suitable width "W" can be from ten (10) mm to five hundred (500) mm, for example 50-100 mm, and the conductors can have a width "We" in the range between twenty (20) micrometers and five hundred (500) micrometers wide, for example one hundred (100) micrometers. Spacing "S" between each conductor ranging from ten (10) micrometers to five hundred (500) micrometers, for example fifty (50) micrometers.

[0072] Turning to Figs. 7-8, a side view and a top view of a display tile 250a including a substrate 252 and having an upper surface 255 is shown where flexible, adhesive side electrode 300 is attached to a flat edge of substrate 252 of display tile 250a using adhesive 306. Top and bottom electrodes 296 are formed making connection with conductor 304. As shown, flexible, adhesive side electrode 300 extends a distance d ₂ from the flat edge of substrate 252. On upper surface 255, top electrodes 296 connect conductor 304 to respective row electrodes 162. [0073] Turning to Figs. 9-10, a side view and a top view of a display tile 250b including a substrate 252 and having an upper surface 255 is shown where flexible, adhesive side electrode 300 is attached to a rounded edge of substrate 252 of display tile 250b using adhesive 306. Top and bottom electrodes 296 are formed making connection with conductor 304. As shown, flexible, adhesive side electrode 300 extends a distance d ₃ from the start of the rounding of the rounded edge of substrate 252. On upper surface 255, top electrodes 296 connect conductor 304 to respective row electrodes 162.

[0074] Turning to Fig. 11, a top perspective view of a display 400 (i.e., a tiled display) including a number of display tiles 250 spaced a sufficient distance from one another to accommodate side electrodes on respective display tiles that each exhibit either straight ends or curved ends. Where, for example, display tiles 250a are used and each has flexible, adhesive side electrode 300 on each end or side, spacing Da is approximately two times d ₂ . Alternatively, where display tiles 250a are used and each has flexible, adhesive side electrode 300 on only one horizontal and one vertical side, spacing Da is approximately d ₂ . As yet another alternative, where display tiles 250b are used and each has flexible, adhesive side electrode 300 on each end or side, spacing Da is approximately two times d ₃ . As yet a further alternative, where display tiles 250b are used and each has flexible, adhesive side electrode 300 on only one horizontal and one vertical side, spacing Da is approximately d ₃ .

[0075] Because flexible, adhesive side electrode 300 extends a considerable distance beyond the edges or sides of each of substrate 252 and therefore a considerable distance from the closest pixel element 158, display 400 includes considerable non-effective display area ln particular, the effective display area is represented by the collective surface area of display tiles 250, and the non-effective display area is represented by the collective areas of the distances Da between display tiles 250. A non-zero value for Da results in an increased pixel pitch (i.e., distance between adjacent pixels) at the transition between display tiles. By reducing the distance Da, the pixel pitch at the transition between display tiles and the ratio of non-effective display area to overall display area (i.e., the sum of the non-effective display area and the effective display area) decreases. By reducing the distance Da to approximately zero, the aforementioned ratio approaches zero and provides for a better visual experience when using such a display. [0076] The display 400 can be any type of display including, but not limited to, a liquid crystal display (LCD), a light emitting diode (LED) display, a micro LED, an electrophoretic display, an e-paper display, and an organic light emitting diode (OLED) display ln some embodiments, the display is a LED and the pixel elements are microLEDs located within five hundred (500) micrometers of an edge surface of at least one display tile 250. ln some embodiments, the display is a LED and the pixel elements are microLEDs located within four hundred (400) micrometers of an edge surface of at least one display tile 250. ln various embodiments, the display is a LED display and the pixel elements are microLEDs located within three hundred (300) micrometers of an edge surface of at least one display tile 250. ln some embodiments, the display is a LED display and the pixel elements are microLEDs located within two hundred (200) micrometers of an edge surface of at least one display tile 250. ln various embodiments, the display is a LED display and the pixel elements are microLEDs located within one hundred (100) micrometers of an edge surface of at least one display tile 250. Alternatively to the tiled display as shown in Figure 11, a single individual substrate can be used within a display device.

[0077] Embodiments discussed below involve recessed side electrodes that effectively move the wrap around edge electrodes described above to within an outer perimeter of substrate 252 or within a coating along the outer perimeter of the substrate 252 of display tile 250 or display device. Moving the electrodes within the outer perimeter and nearer to pixel elements reduces the value of distance Da. ln some cases the outer perimeter of display substrate 252 is coated with an insulator after forming the recessed side electrodes. As used herein, the terms "insulator" or "insulating" are used in their broadest sense to mean any material that does not conduct or only semi-conducts electrical signals. As just some examples, insulating materials may be un-doped silicon (Si) or silicon dioxide (S1O2). Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of insulator or insulating materials that may be used in relation to different embodiments. The insulator extends slightly from the perimeter of display substrate 252 resulting in a non-zero value for the distance Da. This non-zero value for Da, however, can be substantially less than that a value for Da where an external electrode 300 is used. Alternatively, the recessed side electrodes can be formed within this insulating coating material or within a combination of the coating material and the substrate ln various cases, the outer perimeter of display substrate 252 is not coated with such an insulator and in such cases the value of Da can be approximately zero.

[0078] Turning to Fig. 12, a display tile 750 is shown that is similar to that discussed above in relation to Figs. 2-4 except that display tile 750 includes recessed side electrodes 774 disposed within micro-trenches 776 across one side of display tile 750, and recessed side electrodes 764 disposed within micro-trenches 766 across another side of display tile 750. ln particular, display tile 750 includes first substrate 152 comprising a first surface 155, a second surface 157 opposite the first surface 155, and an edge surface 154 between first surface 155 and second surface 157. Edge surface 154 defining an outer perimeter 156 of the display tile.

[0079] While micro -trenches 776, 766 are shown as rounded side recesses into the edge(s) of substrate 152. While micro-trenches 776, 766 are shown as rounded side recesses, other shapes are possible in accordance with other embodiments. For example, micro-trenches may exhibit substantially straight sides, or straight sides with rounded comers. Further, rounded side micro -trenches may be oval or circle shaped. Furthermore, a display tile may include some micro-trenches with one shape, and other micro-trenches with another shape. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of micro-trench shapes that may be used in relation to different embodiments.

[0080] Again, substrate 152 may be made of any suitable material including, but not limited to, a polymeric substrate or a glass based substrate having any desired size and/or shape appropriate to produce a display tile. First surface 155 and second surface 157 may, in certain embodiments, be planar or substantially planar (i.e., substantially flat). First surface 155 and second surface 157 may, in various embodiments, be parallel or substantially parallel. Substrate 152 according to some embodiments may comprise four edges as illustrated in Fig. 12, or may include more than four edges, e.g. a multi-sided polygon ln other embodiments, display tile 750 may include less than four edges, e.g., a triangle. By way of a non-limiting example, substrate 152 may be a rectangle, square, or rhomboid sheet having four edges, although other shapes and configurations are intended to fall within the scope of the disclosure including those having one or more curvilinear portions or edges. [0081] ln certain embodiments, substrate 152 may have a thickness (di shown above in relation to Figs. 2-4) of less than or equal to about 3 mm, for example, ranging from about 0.05 mm to about 3 mm, from about 0.1 mm to about 2.5 mm, from about 0.3 mm to about 2 mm, from about 0.3 mm to about 1.5 mm, from about 0.3 mm to about 1 mm, from about 0.3 mm to about 0.7 mm, or from about 0.3 mm to about 0.5 mm, including all ranges and sub ranges there between.

[0082] First surface 155 of the display tile 750 includes an array of pixel elements 158 arranged in a plurality of rows 160 of pixel elements 158 and a plurality of columns 170 of pixel elements 158. Each row 160 of pixel elements 158 is connected by a row electrode 162, and each column 170 of pixel elements 158 is connected by a column electrode 172. lt will be understood, that the rows 160 and columns 170 of pixel elements 158 that intersect include some of the same pixel elements 158. Thus, there are not two separate sets of pixel elements 158, but one array of pixel elements 158 containing pixel elements 158 that are both connected to separate row and column electrodes. Display tile 750 according to one or more embodiments includes at least one row driver 165 that electrically activates the rows 160 of pixel elements 158 and at least one column driver 175 that electrically activates the columns 170 of pixel elements 158. The row drivers 165 and the column drivers 175 are located opposite first surface 155. ln the embodiment shown in Fig. 12, the row drivers 165 and the column drivers 175 are located on second surface 157 of substrate 152. ln other

embodiments, row drivers 165 and the column drivers 175 can be located on a separate structure disposed opposite first surface 155, such as on a separate substrate (not shown) or other suitable structure.

[0083] As will be appreciated, row drivers 165 and column drivers 175 are connected to row electrodes 162 and column electrodes 172 to activate pixel elements 158. A plurality of recessed side electrodes 764 are provided, and each recessed side electrode 164 provides electrical conductivity between electrical elements on first surface 155 and electrical elements on second surface 157. ln particular, recessed side electrodes 764 provide electrical conductivity between respective row electrodes 162 and corresponding row drivers 165 (or electrical contacts that can be connected to the row drivers or other circuitry); and recessed side electrodes 774 provide electrical conductivity between respective column electrodes 172 and corresponding column drivers 175 (or electrical contacts that can be connected to the column drivers or other circuitry) ln the embodiment shown, each row driver 165 is shown as connecting three rows 160 of pixel elements 158, and each column driver 175 is shown as connecting four columns 170 of pixel elements 158. lt will be understood that this arrangement is for illustration purposes only, and the disclosure is not limited to any particular number of row drivers, column drivers or number of row electrode or column electrodes respectively driven by the row drivers and column drivers. For example, the electrode connectors can exist on only one or multiple edge surfaces 154 based on the specific display design and layout. Furthermore, the disclosure is not limited to any particular number of pixel elements 158 or arrangement of pixel elements 158 on the first surface 155 of the substrate 152.

[0084] Turning to Figs. 13-18 top views of various display tiles are shown having different micro-trench shapes across the display tiles. While all of the micro-trenches shown in Figs. 13-18 are substantially symmetric, such symmetry is not necessary where the micro -trenches are used to provide a location for a recessed side electrode ln some cases, the display tiles include one micro-trench that differs in shape from other micro -trenches on the same display tile. The micro-trench with the different shape may be used, for example, as a registration mark used to align one or more processes or operations carried out in relation to the display tile ln particular, Fig. 13 shows a display tile 790 that includes rounded side micro-trenches 776. ln this case, the rounded side micro-trenches are circular similar to that shown above in relation to Fig. 12. Fig. 14 shows a display tile 791 that includes rounded side micro-trenches 776, and a differently shaped micro-trench 777 that includes a finger extension 783 extending from the back of an otherwise rounded micro-trench. Micro-trench 777 may be used as a registration mark. Fig. 15 shows a display tile 792 that includes rounded side micro-trenches 776, and a differently shaped micro-trench 778 that includes straight sides extending to a rounded area 784. Micro-trench 778 may be used as a registration mark. Fig. 16 shows a display tile 795 that includes straight side micro-trenches 780. Fig. 17 shows a display tile 796 that includes straight side micro -trenches 780, and a differently shaped micro-trench 781 that includes a finger extension 785 extending from the back of an otherwise rounded micro trench. Micro-trench 781 may be used as a registration mark. Fig. 18 shows a display tile 797 that includes straight side micro -trenches 780, and a differently shaped micro-trench 782 where the straight sides make a trapezoid shape instead of the rectangular shape of straight side micro trench 780. Micro-trench 782 may be used as a registration mark. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of micro trench shapes and/or combinations of shapes that may be used in relation to different embodiments.

[0085] Turning to Fig. 19, a flow diagram 800 shows a method for forming display tiles including micro-trenches in accordance with some embodiments. Following flow diagram 800, a glass panel is provided (block 805). As used herein, the term "providing" is used in its broadest sense to mean any action that results in possession of a glass panel. As just some of many examples, providing a glass panel may include, but is not limited to, manufacturing the glass panel, receiving the glass panel from a third party, receiving the glass panel from a different entity controlled by the same party, or simply handling the glass panel. Further, the phrase "glass panel" may be any panel made of a glass based material including, but not limited to, aluminosilicate, alkali-aluminosilicate, borosilicate, alkali-borosilicate, aluminoboro silicate, alkali-aluminoborosilicate, soda lime, or other glasses suitable for displays. Non-limiting examples of commercially available glasses suitable for use as a glass substrate include, for example, EAGLE XG®, LotusTM, and Willow®glasses from Coming lncorporated. As suggested above, the glass panel may be any glass panel that may be processed into glass based substrates as part of manufacturing display tiles.

[0086] The glass panel is singulated to yield multiple display tiles (block 810). Such singluation may be done, for example, by using a laser based cutting tool capable of cutting the glass panel into two or more pieces. Other methods for singulating may be used in relation to different embodiments including, but not limited to, scoring and snapping the lass panel to yield multiple display tiles ln certain embodiments, such singulation is done using a Coming Laser Technology™ (CLT) laser cutting tool to cut individual display tiles from the glass panel. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize other processes that may be used in relation to different embodiments to both singulate the glass panel into individual display tiles.

[0087] Portions of the outer edge of the display tile are modified to include micro-trenches extending into the edge of the display panel (block 815). Various approaches for forming micro-trenches into the edges of display tile may be used in relation to different

embodiments. [0088] ln some embodiments, the processes ofblocks 810 and 815 are combined into a single direct laser cutting that both separates the display tile from the glass panel or mother substrate and forms the micro-trenches in the edges of the display tiles ln some

embodiments, such direct laser cutting is done using a picosecond or femtosecond solid-state laser with the wavelength in the ultraviolet (UV) or infrared (1R) range moved along the glass panel in a pattern that defines the outer perimeter of a given display tile including the desired micro-trenches. An example of this approach is shown in Fig. 20 where a portion 901 of a glass panel 920 is outlined (shown as a dashed line) using the aforementioned solid state laser to define an outer perimeter 905 of a display tile including a substrate 952 and a number of micro-trenches 766, 776 extending into outer perimeter 905. Once outer perimeter 905 and micro-trenches 766, 776 are defined, a CO2 laser with a quenching process or application of liquid nitrogen is applied to create tensile stress or thermal shock along the defined edge of display tile 950. The tensile stress or thermal shock causes separation of the display tile from the glass panel or mother substrate. Such an approach yields display tiles 950 with an upper surface 955 as shown in Fig. 23.

[0089] As shown in Figs. 23-24, display tiles 950 include micro-trenches 766, 776 with inner walls 907. The opening of micro-trenches 766, 776 exhibits a width (w _t ) at outer perimeter 905, a depth (d _t ) from outer perimeter 905, and a separation (W _s ) from an adjacent micro-trench 766, 776 along outer perimeter 905. ln some embodiments, d _t is less than two hundred fifty (250) micrometers ln various embodiments, d _t is less than two hundred (200) micrometers ln various embodiments, d _t is less than one hundred fifty (150) micrometers ln some embodiments, dt is less than one hundred (100) micrometers ln certain embodiments, dt is less than fifty (50) micrometers in some embodiments, dt is less than fifty (50) micrometers ln various embodiments, d _t is less than ten (10) micrometers. Where micro trenches 766, 776 are used to accommodate a recessed side electrode, W _t is selected to have a value sufficient to accommodate the line width and/or design rules used for row electrodes 162 and column electrodes 172. ln certain embodiments, Wt is less than one hundred (100) microns ln some embodiments, W _s is less than two hundred fifty (250) micrometers ln various embodiments, W _s is less than two hundred (200) micrometers ln various embodiments, W _s is less than one hundred fifty (150) micrometers ln some embodiments,

Ws is less than one hundred (100) micrometers ln certain embodiments, W _s is less than fifty (50) micrometers ln some embodiments, W _s is less than fifty (50) micrometers ln various embodiments, W _s is less than ten (10) micrometers. Again, while micro-trenches 766, 776 are show as rounded mirco-trenches of approximately the same size and shape, other embodiments may include micro-trenches with different sizes and shapes. A portion 910 of display tile 950 is shown in greater detail in Fig. 24 where substrate 952 of display tile 950 exhibits thickness di which is was discussed above.

[0090] Alternatively, a Coming Laser Technology™ (CLT) laser cutting tool may be used to cut sinusoidal patterns in the glass panel where the edges of the display tiles are desired. The laser cutting tool separates the individual display tiles from the glass panel. The portion of the sinusoidal pattern extending into the display tile is the micro-trench, and the maximums of the sinusoidal or semi-sinusoidal pattern define the outer perimeter of the display tile. Such an approach results in a display tile similar to display tile 950 described in relation to Fig. 23. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize other direct cutting techniques that may be used in relation to different embodiments to both singulate the glass panel into individual display tiles and to form the micro-trenches in the edges of the display tiles.

[0091] Other embodiments use laser induced etching in a liquid/substrate interface or a solid/substrate interface to cut micro -trenches in the edge(s) of a previously singulated display tile. Such a process is described in relation to Fig. 21 that shows substrate 952 placed against a laser absorption material 997 resulting in an heterogeneous interface 998 between substrate 952 and laser absorption material 997. Where laser absorption material 997 is a liquid, heterogeneous interface 998 is a liquid/substrate interface. Such a liquid laser absorption material may include, but is not limited to, an organic solution like pyrene in the acetone or toluene (i.e., KrF or ArF laser) or inorganic solution like NiSCL or CuSCL. Such absorption material may be used, for example, with a solid state laser (e.g., Nd:YAG laser). Alternatively, where laser absorption material 997 is a solid, heterogeneous interface 998 is a solid/substrate interface. Such a solid laser absorption material may include, but is not limited to, Ag or Sn that can absorb the irradiated laser energy of known wavelengths.

[0092] A laser 916 directs a laser beam 999 of a known wavelength at substrate 952 such that it passes through substrate 952 to heterogeneous interface 998. Laser absorption material 997 absorbs laser energy at the known wavelength resulting in the generation of vapor or heat at heterogeneous interface 998. As this heat transfers through substrate 952, a volume 996 of substrate 952 evaporates or sublimates resulting in a cut. As shown in Fig. 22, as laser 916 is moved along a pattern corresponding to the desired shape and size of a micro-trench volume 996 increases along the pattern and emerges at another location along perimeter 905. The change in volume 996 defines the size and shape of the micro-trench and makes it possible to separate material filing the micro-trench from substrate 952. The surfaces of micro -trenches created using the aforementioned process are rough. Such roughness aids in anchoring a conductive material later formed in the micro-trench. Referring again to Figs. 23-24, after separating the material filing the micro-trench from substrate 952 along volume 996 for a number of cuts along the periphery of substrate 952, what remains is display tile 950 including micro-trenches 766, 776 with inner walls 907.

[0093] Yet other embodiments use a combination of selective material removal processes to form micro-trenches at the edge(s) of display tiles ln some such embodiments, the display tile substrate is masked such that areas where micro-trenches are to be formed remain exposed through the mask. Fig. 25 shows portion 910 of display tile 950 prior to forming micro-trenches ln particular, a masking material 956 is formed over substrate 952 except at locations 957 corresponding to locations where micro-trenches are desired. Masking material 956 may be, but is not limited to, a wet photoresist material applied by spin coating, or spray coating. Masking material 956 may be, but is not limited to, a dry photoresist material applied by lamination. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of masking materials and/or applications processes that may be used in relation to different embodiments.

[0094] Removal of material from substrate 952 is then performed using mechanical etching, wet chemical etching, and/or dry chemical etching ln some embodiments, mechanical etching is used that includes sandblasting locations 957 by impinging sand particles (e.g., S1O2 or AI2O3) at a high velocity from a high pressure system as are known in the art. ln some cases where sand blasting is used, the minimum opening of a completed micro-trench (i.e., Wt) is less than one hundred (100) micrometers. Based on the disclosure provided herein, one of ordinary skill in the art will recognize types of mechanical etching and/or components of mechanical etching that may be used in relation to different embodiments. Such mechanical etching opens micro-trenches 958 shown on Fig. 25. [0095] ln other embodiments, wet chemical etching is used to open micro-trenches at locations 957. Wet chemical etching includes immersing substrate 952 into, for example, diluted HF or buffered HF with ammonium fluoride (NH4F). Such chemicals exhibit an etch rate for the material of substrate 952 that is substantially greater than the etch rate for masking material 956. The diluted HF would react with exposed glass to form a byproduct of silicon tetrafluoride. Alternatively, the buffered HF would produce a byproduct of ammonium fluorosilicate. ln either case, the byproduct can be rinsed from exposed regions of substrate 952 and masking material 956 using deionized water lsotropic wet etching results in rounded micro-trenches similar to micro -trenches 958. The depth (i.e., the distance from the peripheral edge(s) of substrate 952) of the resulting micro -trenches may be governed by either or both of a time that substrate 952 remains immersed in the chemicals or a concentration of the chemicals. Formation of relatively deep micro -trenches having vertical side walls, may be enhanced by introducing sputtered Cr/Au, Cr/Cu or CrON on substrate 952 prior to applying masking material 956. Such wet chemical etching may be desirable where mechanical strength at the edges of substrate 952 is a concern as it can be used to reduce or remove cracks that resulted from the earlier processes of display tile singulation from a glass panel. Wet etching to cure cracks resulting from singulation maybe applied, for example, to the edge(s) of the display tile prior to masking the edge(s) to define locations 957.

[0096] ln yet other embodiments, dry chemical etching is used to open micro-trenches at locations 957. Dry chemical etching may be used, for example, where straight sided micro trenches are desired. Dry chemical etching includes exposing locations 957 to reagents such as, for example, a gas mixture of SFe with O2 or a fluorocarbon based gas (e.g., C2F6, CHF3, C4F6, C4F8) mixed with Ar. The rate of etching is governed by the applied current, biased power, flow rate of gas mixture and gas ratio as is known in the art. Such chemical dry etching is particularly useful where the high aspect ratio walls and/or square shaped micro trenches are desired ln some cases, micro -trenches exhibiting widths (Wt) of less than ten (1 0) microns are formed by a dry chemical process.

[0097] The aforementioned mechanical etching, wet chemical etching, and/or dry chemical etching may be performed on a number of substrates in parallel by stacking the substrates so that edge(s) of the substrates are all exposed to the etching at the same time. For example, in the case of mechanical etching, the substrates may be stacked so that the edges of the multiple substrates are stacked together such that locations 957 across the substrate form a line that can be exposed to, the mechanical etching processes simultaneously ln combination with any of the aforementioned etching, laser ablation, or laser cutting processes shaped, processes such as mechanical grinding or laser processing can be used to chamfer or round the edge comers of the substrates ln some embodiments, the aforementioned etching processes may be extended or modified to undercut at least edge of an inner wall of the micro-trenches or such that at least one wall of a micro-trench is substantially vertical. Such undercutting and/or verticality may be useful in hooking or collecting material such as conductive ink or solder paste during formation of conductive electrodes in the micro trenches.

[0098] Further, as suggested above, none of the aforementioned processes for forming micro-trenches need to be controlled to the extent they yield same dimensions and shape across all micro-trenches where such micro -trenches are to be used for recessed side electrodes lndeed, in some embodiments all of the micro-trenches may be unique from each other due to dissimilarities in size, shape, and/or symmetry.

[0099] Turning to Fig. 27, a flow diagram 801 shows a method for forming recessed side electrodes in accordance with some embodiments. Following flow diagram 801, a number of display tiles are stacked such that an edge of each of the display tiles is exposed, and each of the edges are substantially in the same two-dimensional plane such that together the edges of the display tiles form a top edge surface (block 801). The number of display tiles included in the stack may be as few as two to more than several thousand. An example of such stacked display tiles is shown in Fig. 28 where four (4) display tiles 950 are combined in a stack 912 such that outer perimeter 905 of one edge of each of display tiles 950 are combined to form a top edge surface 914 of stack 912. Walls 907 of micro-trenches 776 are sufficiently aligned to allow fluid movement through micro-channels 908 extending below top edge surface 914 and passing through the sufficiently aligned micro-trenches 776. While stack 912 is shown as including four display tiles 950, fewer than four or more than four display tiles may be stacked to make either larger or smaller stacks.

[00100] Referring again to Fig. 27, a solder paste is applied to the top edge surface (block 811). Any type of solder paste including a conductive material may be used in relation to embodiments. In some embodiments, the solder paste is silver (Ag) solder paste. In other embodiments, the solder paste is tin-silver (Sn and Ag) solder paste. In other embodiments, the solder paste is copper (Cu) solder paste. In yet other embodiments, the solder paste is a tin-copper (Sn and Cu) solder paste. Based upon the disclosure provided herein, one of ordinary skill in the art will appreciate a variety of solder pastes that may be used in relation to different embodiments. A variety of methods may be used to apply the solder paste. In some embodiments, the solder paste is applied using roller coating. In such embodiments, masking may be applied to outer perimeter areas of the edge (e.g., outer perimeter 905 shown in Fig. 28) to avoid formation of solder outside of the micro-trenches. As roller coating the top edge surface of the stack of display tiles with solder paste is performed, pressure is applied to the roller or squeegee to press the solder paste into the micro-trenches. Such application may be performed in a vacuum to facilitate filling of the micro -trenches substantially free of air pockets.

[00101] In other embodiments, the solder paste is screen printed into micro-trenches located across the top edge surface of the stack of display tiles. For screen printing processes, a mask is not needed to avoid formation of solder outside of the micro -trenches. Such application may be performed in a vacuum to facilitate filling of the micro -trenches substantially free of air pockets. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize other processes that may be used in accordance with different embodiments to apply solder paste to the stack of display tiles including, but not limited to, solder paste printing, solder paste dispensing, and solder paste blade coating. Referring to Fig. 29, a solder paste 913 is shown covering the top edge surface 914 and at least partially filling micro-channels 908.

[00102] Referring again to Fig. 27, stack 912 including solder paste 913 is exposed to either UV or thermal energy from an energy source causing the solder paste to liquefy (block 816). Application of the energy to the solder paste results in a separation of the conductive material in the solder paste and the combining of that conductive material in the micro-trenches. Solvents and binders within the solder paste separate and rise, and thus can be wiped away and discarded. Once cooled, the combined conductive material (e.g., Sn, Ag, and/or Cu) forms a static mechanical bond. [00103] When the solder paste is still in its liquid form, the stack of display tiles may be tilted in one or more directions such that gravity causes the liquid conductive material to flow within the micro -channels (block 821). This process is only option and may not be performed in all solder paste implementations. Such flowing maybe used to increase the uniformity of conductive material distribution within each of the micro-trenches. Fig. 30 shows stack 912 after flowing of conductive material 917 within micro -channels 908.

Returning to Fig. 27, the stack of display tiles is cooled and then separated into individual display tiles (block 826). This results in individual display tiles including a conductive material within each of the micro-trenches. This conductive material can be used as a recessed side electrode. During processing, care is taken to assure that conductive material does not form beyond the confines of the micro-trenches to avoid electrical shorts between adjacent recessed side electrodes formed in the micro-trenches.

[00104] ln some embodiments, a modification of the method of Fig. 27 may be used where areas on the display tiles outside of the micro -trenches are first masked leaving the micro trenches exposed, and followed by sputtering a wetting layer of, for example, titanium/copper into the micro-trenches. The stack of display tiles is formed with spacers between each of the respective display tiles. A molten solder paste containing, for example, tin (Sn) with a small amount of copper (Cu) and/or silver (Ag) is reflowed under heating at a temperature between two hundred fifty (250) and three hundred (300) degrees Celsius. The molten solder paste flows naturally into the micro-trenches due to the physical wall confinement and surface tension confinement ln some cases, the stack of display tiles may be tilted such that gravity enhances the flow of the molten solder paste.

[00105] Turning to Fig. 31, a flow diagram 802 shows another method for forming recessed side electrodes in accordance with yet other embodiments. Following flow diagram 802, a number of display tiles are stacked such that an edge of each of the display tiles is exposed, and each of the edges are substantially in the same two-dimensional plane such that together the edges of the display tiles form a top edge surface (block 807). The number of display tiles included in the stack maybe as few as two to more than several thousand. As discussed above, Fig. 28 shows an example stack 912 of four (4) display tiles 950 that are stacked such that outer perimeter 905 of each of display tiles 950 substantially align outer perimeter 905 of one edge of each of display tiles 950 are combined to form a top edge surface 914 of stack 912. Walls 907 of micro-trenches 776 are sufficiently aligned to allow fluid movement through micro-channels 908 extending below top edge surface 914 and passing through the sufficiently aligned micro-trenches 776.

[00106] Referring again to Fig. 31, the micro -trenches along the top edge surface of the stack, and thus fills each of the micro-channels are filled with a nanoparticle solution or suspension lock 812). The nanoparticle solution or suspension maybe any conductive material containing nanoparticle solution or suspension known in the art. ln some embodiments, a nanoparticle solution containing copper oxide (CuO) is used ln other embodiments, a nanoparticle solution containing silver oxide (AgO) is used. Fig. 32 shows each of micro-trenches 776 along top edge surface 914 of stack 912 (and thus each of micro channels 908) filled with a nanoparticle solution or suspension 917. Returning to Fig. 31, the nanoparticle solution or suspension is allowed to dry at a temperature below one hundred fifty (150) degrees Celsius (block 817). The drying results in a deposition of conductive nanoparticles (e.g., CuO or AgO) from the nanoparticle solution or suspension inside the micro-trenches. To provide for wetting between the nanoparticle solution or suspension and the walls of the micro -trenches, pre-treatment of the walls of the micro-trenches with UV- ozone or O2 plasma may be used.

[00107] Laser radiation is directed toward the deposited conductive nanoparticles within the micro-trenches resulting in reduction to metal particles (e.g., Cu or Ag), and agglomeration of the metal particles into a continuous conductive layer across the respective micro-channels (block 822). Non-irradiated nanoparticles can be rinsed away using deionized (Dl) water.

Fig. 33 shows a continuous conductive layers 918 extending across micro-trenches 776 along top edge surface 914 of stack 912 (and thus in each of micro-channels 908). Returning to Fig. 31, the stack of display tiles is cooled and then separated into individual display tiles (block 827). This results in individual display tiles including a conductive material within each of the micro-trenches. This conductive material can be used as a recessed side electrode.

[00108] Turning to Fig. 34, a flow diagram 803 shows another method for forming recessed side electrodes in accordance with yet other embodiments. Following flow diagram 803, a number of display tiles are stacked such that an edge of each of the display tiles is exposed, and each of the edges are substantially in the same two-dimensional plane such that together the edges of the display tiles form a top edge surface (block 808). The number of display tiles included in the stack maybe as few as two to more than several thousand. As discussed above, Fig. 28 shows an example stack 912 of four (4) display tiles 950 that are stacked such that outer perimeter 905 of each of display tiles 950 substantially align outer perimeter 905 of one edge of each of display tiles 950 are combined to form a top edge surface 914 of stack 912. Walls 907 of micro-trenches 776 are sufficiently aligned to allow fluid movement through micro-channels 908 extending below top edge surface 914 and passing through the sufficiently aligned micro-trenches 776.

[00109] Returning to Fig. 34, a seed layer of conductive material is selectively deposited into each of a number of micro -trenches across the top edge surface of the stack (block 813). The deposition may be done, for example, by sputtering a seed material onto the walls of each of the micro-trenches. The seed layer includes any seed material that may be used to control plating with a selected conductive material ln some embodiments, the seed material may be, for example, titanium/ copper based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of seed materials and/or methods for depositing the seed materials that maybe used in relation to different embodiments. The stack of display tiles may be formed with spacers between each of the respective display tiles.

[00110] The stack of display tiles is then exposed to a plating process that grows a conductive material layer on the seed material previously deposited on the walls of each of the micro -trenches (block 818). Such plating may be electrode based plating or non-electrode plating as are known in the art. Fig. 35 shows conductive layers 919 extending across micro trenches 776 along top edge surface 914 of stack 912 (and thus in each of micro-channels 908). Returning to Fig. 34, the stack of display tiles is separated into individual display tiles (block 823). This results in individual display tiles including a conductive material within each of the micro-trenches. This conductive material can be used as a recessed side electrode.

[00111] Turning to Fig. 36, is the side perspective view of previously described Fig. 24 augmented to show portion 910 after formation of a side electrodes 981 within micro trenches 776 and formation of an insulating layer (i.e., passivation layer) 983 over side electrodes 981. lnsulating layer 981 extends a distance di from outer perimeter 905. ln some cases, di is substantially less than, for example, d ₂ discussed above in relation to Fig. 7. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of ways for forming insulating over a substrate or substrate side.

[00112] ln conclusion, various novel systems, devices, methods and arrangements for edge electrodes. While detailed descriptions of one or more embodiments have been given above, various alternatives, modifications, and equivalents will be apparent to those skilled in the art without varying from the spirit of the invention. Therefore, the above description should not be taken as limiting the scope of the invention, which is defined by the appended claims.