CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of U.S. Provisional Application Serial No. 62/894,072 filed on August 30, 2019 the content of which is relied upon and incorporated herein by reference in its entirety.

FIELD

[0002] The present specification generally relates to display protector assemblies and, more particularly, to display protector assemblies having selectively thinned layers.

BACKGROUND

[0003] A display of an electronic device, such as a mobile phone and a tablet, may be implemented by a plurality of layers. For example, the display of the electronic device may include a cover glass that is disposed on a digital display panel (e.g., a liquid crystal display (LCD) panel), one or more indium-tin-oxide (1TO) layers, one or more adhesive layers, and a capacitive sensor network. Furthermore, in order to protect the cover glass from dynamic loading and/or impact forces, a user of the electronic device may decide to attach a display protector to the cover glass of the electronic device. Example display protectors include 3D glass screen protectors, 2.5D glass screen protectors, and 2D glass screen protectors.

[0004] The electronic device may include various sensors configured to obtain biometric information or other identifying indicia of a user in order to perform user authentication functions. As an example, the electronic device may include an ultrasonic fingerprint sensor located underneath the cover glass and the digital display panel of the electronic device. Specifically, the ultrasonic fingerprint sensor may transmit ultrasonic signals (e.g., acoustic signals) in order to scan a user’s finger and generate a 3D image of the user’s finger/fingerprint. Subsequently, the electronic device may activate or enable certain functions based on the generated 3D image (i.e., if the generated 3D image matches a 3D image profile associated with the electronic device, the electronic device may unlock and make certain applications available to the user). However, the working distance of these fingerprint sensors may be limited (e.g., 800 microns), therefore making the integration of a mechanically robust display protector with these electronic devices difficult.

[0005] Accordingly, a need exists for alternative display protectors that are mechanically robust and enable the operation of ultrasonic fingerprint sensors disposed on the cover glass of the electronic device.

SUMMARY

[0006] In one embodiment, a screen protector assembly includes an adhesive layer and a glass-based substrate having a central portion. The glass-based substrate is disposed on the adhesive layer. The central portion includes a first region, a second region, and a transition region. The first region of the central portion has a first thickness, the second region of the central portion has a second thickness, and the first thickness is less than the second thickness. The transition region is located between the first region of the central portion and the second region of the central portion.

[0007] In another embodiment, a screen protector assembly includes an adhesive layer and a glass-based substrate including a central portion, an edge portion, and a transition portion. The glass-based substrate is disposed on the adhesive layer. The edge portion is disposed on a perimeter of the transition portion, the transition portion is disposed on a perimeter of the central portion, and the transition portion is located between the edge portion and the central portion. The central portion has a first thickness, the edge portion has a second thickness, and the first thickness is less than the second thickness.

[0008] In yet another embodiment, an electronic device includes an acoustic fingerprint sensor operable to emit an acoustic signal at a signal frequency. The electronic device also includes an electronic display disposed on the acoustic fingerprint sensor and a cover glass disposed on the electronic display. The electronic device also includes a screen protector assembly disposed on the cover glass, wherein the screen protector assembly includes a glass- based substrate having a first portion and a second portion, and wherein the screen protector assembly includes an adhesive layer. The glass-based substrate is disposed on the adhesive layer. The first portion of the glass-based substrate has a first thickness, and the second portion of the glass-based substrate has a second thickness. In response to the first portion receiving an external force, the first portion of the glass-based substrate is configured to bend and reduce a distance between the acoustic fingerprint sensor and an upper surface of the first portion of the glass-based substrate.

[0009] According to aspect (1), a screen protector assembly is provided. The screen protector assembly comprises: an adhesive layer; a glass-based substrate having a central portion, wherein: the glass-based substrate is disposed on the adhesive layer; the central portion comprises a first region, a second region, and a transition region; the first region of the central portion has a first thickness; the second region of the central portion has a second thickness; the first thickness is less than the second thickness; and the transition region is located between the first region of the central portion and the second region of the central portion. [0010] According to aspect (2), the screen protector assembly of aspect (1) is provided, wherein the transition region comprises: a first end proximate to the first region of the central portion; and a second end proximate to the second region of the central portion, wherein a thickness of the transition region gradually increases from the first end to the second end.

[0011] According to aspect (3), the screen protector assembly of aspect (1) is provided, wherein the transition region comprises: a step region having a first step region end and a second step region end, wherein: the first region of the central portion is proximate to the first step region end; the second region of the central portion is proximate to the second step region end; and at least a portion of the step region is perpendicular to at least one of the first region of the central portion and the second region of the central portion.

[0012] According to aspect (4), the screen protector assembly of aspect (3) is provided, comprising a filler material, wherein: the first region of the central portion is disposed on the filler material; and the filler material has a third thickness.

[0013] According to aspect (5), the screen protector assembly of aspect (4) is provided, wherein the filler material is transparent in a visible spectrum.

[0014] According to aspect (6), the screen protector assembly of aspect (4) or (5) is provided, wherein a sum of the first thickness and the third thickness is equal to the second thickness.

[0015] According to aspect (7), the screen protector assembly of any of aspects (4) to (6) is provided, wherein a thickness of the transition region increases from the first step region end to the second step region end. [0016] According to aspect (8), the screen protector assembly of aspect (3) is provided, wherein a thickness of the transition region increases from the first step region end to the second step region end.

[0017] According to aspect (9), the screen protector assembly of any of aspects (1) to (8) is provided, further comprising a film layer and an adhesive layer, wherein: the glass-based substrate is disposed on the film layer; and the film layer is disposed on the adhesive layer.

[0018] According to aspect (10), the screen protector assembly of aspect (9) is provided, wherein a sum of the first thickness, a thickness of the film layer, and a thickness of the adhesive layer is less than or equal to 0.6 millimeters.

[0019] According to aspect (11), the screen protector assembly of aspect (9) or (10) is provided, wherein the adhesive layer is transparent in a visible spectrum.

[0020] According to aspect (12), a screen protector assembly is provided. The screen protector assembly comprises: an adhesive layer; a glass-based substrate having a central portion, an edge portion, and a transition portion, wherein: the glass-based substrate is disposed on the adhesive layer; the edge portion is disposed on a perimeter of the transition portion; the transition portion is disposed on a perimeter of the central portion; the transition portion is located between the edge portion and the central portion; the central portion has a first thickness; the edge portion has a second thickness; and the first thickness is less than the second thickness.

[0021] According to aspect (13), the screen protector assembly of aspect (12) is provided, wherein: the transition portion comprises a first end and a second end; the first end is proximate to the central portion; and the second end is proximate to the edge portion. [0022] According to aspect (14), the screen protector assembly of aspect (13) is provided, wherein a thickness of the transition portion gradually increases from the first end to the second end.

[0023] According to aspect (15), the screen protector assembly of any of aspects (12) to (14) is provided, wherein the second thickness is greater than or equal to 0.2 millimeters and less than or equal to 1 millimeter.

[0024] According to aspect (16), the screen protector assembly of any of aspects (12) to (15) is provided, further comprising a film layer and an adhesive layer, wherein: the glass-based substrate is disposed on the film layer; and the film layer is disposed on the adhesive layer.

[0025] According to aspect (17), the screen protector assembly of aspect (16) is provided, wherein a sum of the first thickness, a thickness of the film layer, and a thickness of the adhesive layer is less than or equal to 0.6 millimeters.

[0026] According to aspect (18), an electronic device is provided. The electronic device comprises: an acoustic fingerprint sensor operable to emit an acoustic signal at a signal frequency; an electronic display disposed on the acoustic fingerprint sensor; a cover glass disposed on the electronic display; and a screen protector assembly disposed on the cover glass, wherein the screen protector assembly comprises a glass-based substrate having a first portion and a second portion, wherein the screen protector assembly comprises an adhesive layer, and wherein: the glass-based substrate is disposed on the adhesive layer; the first portion of the glass-based substrate has a first thickness; the second portion of the glass-based substrate has a second thickness; and in response to the first portion receiving an external force, the first portion of the glass-based substrate is configured to bend and reduce a distance between the acoustic fingerprint sensor and an upper surface of the first portion of the glass- based substrate.

[0027] According to aspect (19), the electronic device of aspect (18) is provided, wherein the adhesive layer is transparent in a visible spectrum.

[0028] According to aspect (20), the electronic device of aspect (18) or (19) is provided, further comprising a film layer, wherein: the glass-based substrate is disposed on the film layer; and the film layer is disposed on the adhesive layer.

[0029] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The embodiments set forth in the drawings are illustrative and exemplary in nature and are not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which: [0031] FIG. 1A schematically depicts a perspective view of an example display protector assembly according to one or more embodiments described and illustrated herein;

[0032] FIG. IB schematically depicts a cross-sectional view of the example display protector assembly of FIG. 1A according to one or more embodiments described and illustrated herein;

[0033] FIG. 2A schematically depicts a perspective view of an example geometry of a glass- based substrate of the display protector assembly according to one or more embodiments described and illustrated herein;

[0034] FIG. 2B schematically depicts a cross-sectional view of the example geometry of the glass-based substrate of FIG. 2A according to one or more embodiments described and illustrated herein;

[0035] FIG. 3A schematically depicts a perspective view of another example geometry of a glass-based substrate of the display protector assembly according to one or more embodiments described and illustrated herein;

[0036] FIG. 3B schematically depicts a cross-sectional view of the example geometry of the glass-based substrate of FIG. 3A according to one or more embodiments described and illustrated herein;

[0037] FIG. 3C schematically depicts another cross-sectional view of the example geometry of the glass-based substrate of FIG. 3A according to one or more embodiments described and illustrated herein;

[0038] FIG. 4A schematically depicts a perspective view of yet another example geometry of a glass-based substrate of the display protector assembly according to one or more embodiments described and illustrated herein; [0039] FIG. 4B schematically depicts a cross-sectional view of the example geometry of the glass-based substrate of FIG. 4A according to one or more embodiments described and illustrated herein;

[0040] FIG. 4C schematically depicts another cross-sectional view of the example geometry of the glass-based substrate of FIG. 4A according to one or more embodiments described and illustrated herein;

[0041] FIG. 5A schematically depicts a perspective view of an example electronic device with a sensor disposed under a display panel and a cover glass of the electronic device according to one or more embodiments described and illustrated herein;

[0042] FIG. 5B schematically depicts an exploded cross-sectional view of FIG. 5A according to one or more embodiments described and illustrated herein;

[0043] FIG. 6A schematically depicts a perspective view of a display protector assembly according to one or more embodiments described and illustrated herein;

[0044] FIG. 6B schematically depicts a cross-sectional view of the display protector assembly of FIG. 6A according to one or more embodiments described and illustrated herein;

[0045] FIG. 7A schematically depicts a perspective view of another display protector assembly according to one or more embodiments described and illustrated herein;

[0046] FIG. 7B schematically depicts a cross-sectional view of the display protector assembly of FIG. 7A according to one or more embodiments described and illustrated herein;

[0047] FIG. 8A schematically depicts a perspective view of yet another display protector assembly according to one or more embodiments described and illustrated herein; [0048] FIG. 8B schematically depicts a cross-sectional view of the display protector assembly of FIG. 8A according to one or more embodiments described and illustrated herein;

[0049] FIG. 9A schematically depicts a perspective view of yet another display protector assembly according to one or more embodiments described and illustrated herein;

[0050] FIG. 9B schematically depicts a cross-sectional view of the display protector assembly of FIG. 9A according to one or more embodiments described and illustrated herein;

[0051] FIG. 10A schematically depicts a perspective view of yet another display protector assembly according to one or more embodiments described and illustrated herein;

[0052] FIG. 10B schematically depicts a cross-sectional view of the display protector assembly of FIG. 10A according to one or more embodiments described and illustrated herein;

[0053] FIG. IOC schematically depicts another cross-sectional view of the display protector assembly of FIG. 10A according to one or more embodiments described and illustrated herein;

[0054] FIG. 11A schematically depicts a perspective view of yet another display protector assembly according to one or more embodiments described and illustrated herein;

[0055] FIG. 11B schematically depicts a cross-sectional view of the display protector assembly of FIG. 11A according to one or more embodiments described and illustrated herein; [0056] FIG. l lC schematically depicts another cross-sectional view of the display protector assembly of FIG. 11A according to one or more embodiments described and illustrated herein;

[0057] FIG. 12A schematically depicts a perspective view of yet another display protector assembly according to one or more embodiments described and illustrated herein;

[0058] FIG. 12B schematically depicts a cross-sectional view of the display protector assembly of FIG. 12A according to one or more embodiments described and illustrated herein;

[0059] FIG. 12C schematically depicts another cross-sectional view of the display protector assembly of FIG. 12A according to one or more embodiments described and illustrated herein

[0060] FIG. 13A schematically depicts a perspective view of yet another display protector assembly according to one or more embodiments described and illustrated herein; and

[0061] FIG. 13B schematically depicts a cross-sectional view of the display protector assembly of FIG. 13A according to one or more embodiments described and illustrated herein.

DETAILED DESCRIPTION

[0062] Referring generally to the figures, embodiments of the present disclosure are generally related to display protector assemblies for electronic devices that enable the transmission of ultrasonic signals while maintaining mechanical robustness. The display protector assemblies may be disposed on various electronic devices including, but not limited to, a mobile device (e.g., a smartphone, tablet, laptop, PDA, or other similar mobile devices). As used herein, the phrase “disposed on” can describe a spatial or functional relationship between two or more elements. Unless explicitly described as being “direct,” the relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements.

[0063] More particularly, display protector assemblies in accordance with embodiments described herein comprise a glass-based substrate that is selectively thinned to enable the transmission of ultrasonic signals transmitted by a sensor located underneath a glass layer of the electronic device. By selectively thinning certain regions of the glass-based substrate of the display protector assembly, the display protector assemblies can effectively transmit ultrasonic signals and simultaneously have a sufficient mechanical robustness to protect the electronic device from impact forces. Specifically, by selectively thinning the glass-based substrate of the display protector assembly, the distance between the sensor and the upper surface of the glass-based substrate is minimized, thereby enabling a user to bring his or her finger within a working distance of the sensor. Furthermore, by selectively thinning the glass- based substrate of the display protector assembly, the impact of interference from layers between the user’s finger and the sensor is minimized, thereby improving the functionality of the sensor and the accuracy of the authentication algorithms executed by the electronic device.

[0064] In some embodiments described herein, the glass-based substrate of the display protector assembly includes a thin glass-based substrate that is configured to bend in response to, for example, a user applying a force with his or her finger to the glass-based substrate of the display protector assembly. Accordingly, the display protector assemblies can effectively transmit ultrasonic signals to the user’s finger due to the decreased distance between the user’s finger and the sensor. [0065] In some embodiments described herein, the display protector assembly includes an adhesive that is configured to compress in response to, for example, a user applying a force with his or her finger to the glass-based substrate of the display protector assembly. Accordingly, the display protector assemblies can effectively transmit ultrasonic signals to the user’s finger due to the decreased distance between the user’s finger and the sensor.

[0066] Referring now to FIGS. 1A and IB, a top view and a partial cross-section view along 1B-1B, respectively, of a display protector assembly 10 disposed on an electronic device 20 are schematically depicted. In the illustrated embodiment, the display protector assembly 10 includes a glass-based substrate 12, a film layer 14, and an adhesive layer 16, and the electronic device 20 may include a cover glass 22. While not depicted, it should be understood that the electronic device 20 may include other components, such as a display panel (e.g., a liquid crystal display (LCD) panel, an organic light-emitting diode (OLED) display, etc.), one or more indium-tin-oxide (1TO) layers, one or more adhesive layers, a capacitive sensor network, one or more processing circuits, and one or more nontransitory computer-readable mediums, such as a random-access memory and/or read-only memory.

[0067] The glass-based substrate 12 may include a central portion 12A and an edge portion 12B disposed around a perimeter of the central portion 12A. The central portion 12A may be aligned with a display of the electronic device 20, and the edge portion 12B may be aligned with an edge of the display of the electronic device 20. Furthermore, the glass-based substrate 12 may include a lower surface 12C and an upper surface 12D.

[0068] As utilized herein, “glass-based” refers to an article that includes or is wholly made of glass, such as a glass or glass-ceramic material. In embodiments, the glass-based substrate 12 may include, but is not limited to, a fused silica material, a float glass material, a glass- ceramic material, a tempered glass material, alkali containing glass (e.g., an alkali aluminosilicate glass material), alkali-free glass (e.g., alkali-free alkaline aluminoborosilicate glass), a ceramic material, or other similar glass-based materials.

[0069] As a non-limiting example, the glass-based substrate 12 may be an alkali aluminosilicate glass composition that comprises from about 60 mol % to about 70 mol % S1O2; from about 6 mol % to about 14 mol % AI2O3; from 0 mol % to about 15 mol % B2O3; from 0 mol % to about 15 mol % L12O; from 0 mol % to about 20 mol % Na ₂ 0; from 0 mol % to about 10 mol % K2O; from 0 mol % to about 8 mol % MgO; from 0 mol % to about 10 mol % CaO; from 0 mol % to about 5 mol % ZrCh; from 0 mol % to about 1 mol % SnCk; from 0 mol % to about 1 mol % CeCk; less than about 50 ppm AS2O3; and less than about 50 ppm Sb ₂ C> ₃ ; wherein 12 mol % — Li ₂ 0+Na ₂ 0+K ₂ 0<20 mol % and 0 mol %<MgO+CaO<10 mol %. As another non-limiting example, the alkali aluminosilicate glass composition comprises at least about 50 mol % SiCk and at least about 11 mol % Na ₂ 0, and the compressive stress is at least about 900 MPa. In some embodiments, the glass-based substrate 12 further comprises AI2O3 and at least one of B2O3, K2O, MgO and ZnO, wherein -340+27.1.Al ₂ O3-28.7.B ₂ O3+15.6.Na ₂ O-61.4.K ₂ O+8.1. (MgO+ZnO) > 0 mol %. In some embodiments, the glass comprises from about 7 mol % to about 26 mol % AI2O3; from 0 mol % to about 9 mol % B2O3; from about 11 mol % to about 25 mol % Na ₂ 0; from 0 mol % to about 2.5 mol % K2O; from 0 mol % to about 8.5 mol % MgO; and from 0 mol % to about 1.5 mol % CaO.

[0070] The glass-based substrate 12 may have a thickness between 0.2 and 1.0 millimeters (e.g., 0.4 millimeters), but it should be understood that the glass-based substrate 12 may have any suitable thickness. As non-limiting examples, the glass-based thickness may be between 0.2 and 0.3 millimeters, between 0.2 and 0.4 millimeters, between 0.2 and 0.5 millimeters, between 0.2 and 0.6 millimeters, between 0.2 and 0.7 millimeters, between 0.2 and 0.8 millimeters, between 0.2 and 0.9 millimeters, and between 0.2 and 1.0 millimeters.

[0071] In some embodiments, the glass-based substrate 12 may be chemically or thermally strengthened. As a non-limiting example, the glass-based substrate 12 may be chemically strengthened using an ion exchange process. In an ion exchange process, ions in a surface layer of the glass-based substrate 12 are replaced by, or exchanged with, larger ions in a bath solution (e.g., a salt bath) having the same valence or oxidation state. It will be appreciated by those skilled in the art that parameters for the ion exchange process including, but not limited to, bath composition and temperature, immersion time, the number of immersions of the glass in a salt bath (or baths), use of multiple salt baths, additional steps such as annealing, washing, and the like, are generally determined by the composition of the glass- based substrate 12 and the desired depth of layer and compressive stress of the glass-based substrate 12 as a result of the strengthening operation. As a non- limiting example, when the glass-based substrate 12 includes an alkali aluminosilicate glass material, ions in the surface layer of the glass-based substrate 12 and the larger ions in the bath may be monovalent alkali metal cations, such as Li ⁺ (when present in the glass-based substrate 12), Na ⁺ , K ⁺ , Rb ⁺ , and Cs ⁺ . Alternatively, monovalent cations in the surface layer may be replaced with monovalent cations other than alkali metal cations, such as Ag ⁺ or the like.

[0072] The glass-based substrate 12 may have various geometries. For example and as schematically depicted in FIGS. 2A and 2B (which is a cross-section view of FIG. 2A along 2B-2B), an example glass-based substrate 12-1 has a dish geometry. As used herein, the dish geometry means that each edge 24A, 24B, 24C, and 24D of the edge portion 12B is curved such that glass-based substrate 12-1 has a dish shape. As another non-limiting example and as schematically depicted in FIGS. 3A, 3B (which is a cross-section view of FIG. 3A along 3B- 3B), and 3C (which is a cross-section view of FIG. 3A along 3C-3C), an example glass-based substrate 12-2 has a sled geometry. As used herein, the sled geometry means that only a corresponding pair (i.e., edges 24A and 24C or edges 24B and 24D) of the edge portion 12B is curved such that the glass-based substrate 12-2 has a sled shape. For example and as schematically depicted in FIGS. 4A, 4B (which is a cross-section view of FIG. 4A along 4B- 4B), and 4C (which is a cross-section view of FIG. 4A along 4CAC), an example glass-based substrate 12-3 may have a combination of dish geometry and the sled geometry.

[0073] Referring once again to FIGS. 1A and IB, the lower surface 12C of the glass-based substrate 12 is disposed on and bonded to the film layer 14, which may be an anti-splinter film and/or a decorative film. As a non-limiting example, the film layer 14 is configured to prevent the dispersion of glass splinters and/or other particles in the event that the glass-based substrate 12 is broken. Illustrative example materials for the film layer 14 include, but are not limited to, a polycarbonate material, polyethylene terephthalate (PET) material, polypropylene material, polyester material, and/or acrylic material. For example, the film layer 14 may have a thickness that is less than or equal to 0.1 millimeters (e.g., 0.08 millimeters). It should be understood that other thicknesses may be provided. In some embodiments, the film layer 14 may be removed from the display protector assembly 10, and as such, the lower surface 12C of the glass-based substrate 12 may be disposed on and bonded to the adhesive layer 16 (i.e., the film layer 14 can be an optional component of the display protector assembly 10).

[0074] The adhesive layer 16 bonds the film layer 14 and the glass-based substrate 12 of the display protector assembly 10 to the cover glass 22 of the electronic device 20. In some embodiments, the adhesive layer 16 comprises a plurality of optically clear layers that are transparent in the visible spectrum. As a non- limiting example, the adhesive layer 16 may include a first layer comprising a high-adhesion material, a second layer comprising a PET material, and a third layer comprising a low-adhesion silicone layer. In some embodiments, the adhesive layer 16 may include other polymer-based materials, acrylic -based materials, and/or other similar bonding materials. In embodiments, the adhesive layer 16 may have a thickness that is greater than or equal to 0.05 millimeters and less than or equal to 0.45 millimeters (e.g., 0.4 millimeters). It should be understood that other thicknesses may be provided.

[0075] The cover glass 22 of the electronic device 20 is disposed on the display layer, one or more 1TO layers, one or more adhesive layers, and a capacitive sensor network of the electronic device 20. Example non-limiting materials for the cover glass 22 of the electronic device 20 include a silica-based glass material, a tempered glass material, a glass substrate, a glass-ceramic material, or other similar glass material. In some embodiments, the cover glass 22 comprises an alkali aluminosilicate glass composition. As a non-limiting example, the alkali aluminosilicate glass composition comprises from about 60 mol % to about 70 mol % SiCE; from about 6 mol % to about 14 mol % AI2O3; from 0 mol % to about 15 mol % B2O3; from 0 mol % to about 15 mol % L12O; from 0 mol % to about 20 mol % Na20; from 0 mol % to about 10 mol % K2O; from 0 mol % to about 8 mol % MgO; from 0 mol % to about 10 mol % CaO; from 0 mol % to about 5 mol % ZrCE; from 0 mol % to about 1 mol % SnCk; from 0 mol % to about 1 mol % CeCk; less than about 50 ppm AS2O3; and less than about 50 ppm Sb203; wherein 12 mol % — Li ₂ 0+Na ₂ 0+K ₂ 0<20 mol % and 0 mol %<MgO+CaO<10 mol %. As another non-limiting example, the alkali aluminosilicate glass composition comprises at least about 50 mol % SiCE and at least about 11 mol % Na ₂ 0, and the compressive stress is at least about 900 MPa. In some embodiments, the cover glass 22 further comprises AI2O3 and at least one of B2O3, K2O, MgO and ZnO, wherein -340+27.1.Aΐ ₂ q ₃ -28.7.B ₂ q ₃ +15.6.NB ₂ q-61.4.K ₂ O+8.1. (MgO+ZnO) > 0 mol %. In some embodiments, the glass comprises from about 7 mol % to about 26 mol % AI2O3; from 0 mol % to about 9 mol % B2O3; from about 11 mol % to about 25 mol % Na ₂ 0; from 0 mol % to about 2.5 mol % K ₂ 0; from 0 mol % to about 8.5 mol % MgO; and from 0 mol % to about 1.5 mol % CaO.

[0076] Referring now to FIGS. 5A and 5B, a perspective view and cross-sectional view along 5B-5B, respectively, an example electronic device 20 with a sensor 26 disposed under the cover glass 22 and a display layer 23 of the electronic device 20 are schematically depicted. The display layer 23 may be implemented by, for example, an LCD panel or an OLED panel. As described above, the sensor 26 may be configured to obtain biometric information or other identifying indicia of a user in order for the electronic device 20 to perform user authentication functions. For example, the sensor 26 may be an acoustic fingerprint sensor that is configured to transmit ultrasonic signals (e.g., acoustic signals) to scan a user’s finger to generate a 3D image of the user’s finger/fingerprint. Subsequently, the electronic device 20 may activate or enable, using a processor of the electronic device 20 (not shown), certain functions based on the generated 3D image (i.e., if the generated 3D image matches a 3D image profile associated with the electronic device 20, the electronic device 20 may unlock and make certain applications available to the user).

[0077] However, the sensor 26 must transmit ultrasonic signals through multiple layers of the electronic device 20 (e.g., the cover glass 22, the display layer 23, etc.) and the display protector assembly 10 (e.g., the glass-based substrate 12, the film layer 14, and the adhesive layer 16). Furthermore, the sensor 26 has a limited and finite working distance (e.g., 800 microns). Accordingly, a thickness of the glass-based substrate 12 of the display protector assembly 10 may need to be decreased in order to ensure that the sensor 26 can sufficiently transmit ultrasonic signals through the electronic device 20 and the display protector assembly 10. Reducing the thickness of the glass-based substrate 12, however, may reduce the mechanical robustness of the display protector assembly 10 and therefore make the electronic device 20 more susceptible to damage from impact forces and/or dynamic loading.

[0078] Accordingly, the thickness of the glass-based substrate 12 of the display protector assembly 10 may be selectively thinned in order to ensure that the sensor 26 can sufficiently transmit ultrasonic signals through the electronic device 20 and the display protector assembly 10. The selective thinning may be implemented at various regions of the glass- based substrate 12. As a non-limiting example, an area of the central portion 12A of the glass-based substrate 12 that is aligned with the sensor 26 may be thinner compared to other regions of the central portion 12A, as described below in further detail. As another non limiting example, the central portion 12A may be thinner than the edge portion 12B, as described below in further detail. Moreover, any one of or both the upper surface 12D and the lower surface 12C of the glass-based substrate 12 may be selectively thinned.

[0079] By selectively thinning the glass-based substrate 12, the distance between the sensor 26 and the upper surface 12D of the glass-based substrate 12 is minimized, thereby enabling a user to bring his or her finger within a working distance of the sensor 26. Further, due to the minimized distance between the sensor 26 and the user’s finger, the impact of acoustic interference from layers between the user’s finger and the sensor 26 is minimized, thereby improving the functionality of the sensor 26 and the accuracy of the authentication algorithms executed by the electronic device 20.

[0080] In addition to minimizing the distance between the user’s finger and the sensor 26, selectively thinning the glass-based substrate 12 enables the display protector assembly 10 to have a sufficient mechanical robustness. As described below in further detail, the areas of the glass-based substrate 12 that are not aligned with the sensor 26 of the electronic device 20 may not be thinned. Therefore, these non-thinned areas of the glass-based substrate 12 may have a sufficient thickness that prevents the cover glass 22 from being damaged in response to impact forces or dynamic loading.

[0081] Referring now to FIGS. 6A and 6B, a perspective view and a partial cross-section view along 6B-6B, respectively, of an example display protector assembly 10-1 disposed on the electronic device 20 are schematically depicted. The glass-based substrate 12 of the display protector assembly 10-1 is selectively thinned on the upper surface 12D. Further, a thickness of the glass-based substrate 12 of the display protector assembly 10-1 gradually increases from a first thickness (Ti) to a second thickness (T2).

[0082] As illustrated, the glass-based substrate 12 includes the central portion 12A and the edge portion 12B, which is disposed on a perimeter of the central portion 12A. The central portion 12A includes a first region 34, a second region 36, and a transition region 38 located between the first region 34 and the second region 36. In the illustrated embodiment, the first region 34 of the central portion 12A is aligned with the sensor 26 of the electronic device 20. The first region 34 of the central portion 12A has the first thickness (Ti), and the second region 36 of the central portion 12A has the second thickness (T2), wherein the first thickness is less than the second thickness. The first thickness (Ti) may be less than the second thickness (T2) such that a user can place his or her finger within the working distance of the sensor 26. The second thickness (T2) may be a value that enables the display protector assembly 10-1 to have a sufficient mechanical robustness. [0083] The transition region 38 includes a first end 40 and a second end 42. The first end 40 is proximate to the first region 34 of the central portion 12A, and the second end 42 is proximate to the second region 36 of the central portion 12A. As defined herein, the term proximate means near or adjacent. As a non-limiting example, the first end 40 may be aligned with a region of the central portion 12A in which a slope of the central portion 12A changes from zero to a non-zero value. As another non-limiting example, second end 42 may be aligned with a region of the central portion 12A in which a slope of the central portion 12A changes from a non-zero value to zero.

[0084] As schematically depicted in FIG. 6B, a thickness of the transition region 38 gradually increases from the first end 40 to the second end 42. In the illustrated embodiment, the thickness of the transition region 38 linearly increases from the first end 40 to the second end 42. In some embodiments, the transition region 38 may gradually increase from the first end 40 to the second end 42 in a nonlinear manner (e.g., a plurality of gradual step increases from the first end 40 to the second end 42). A slope and/or geometry of the gradual increase may be based on, for example, the precision and/or accuracy of machining devices utilized to form the transition region 38. As a non-limiting example, the thickness of the transition region 38 may linearly increase by 0.15 millimeters from the first end 40 to the second end 42.

[0085] In the illustrated embodiment, a first summation value, which is a sum of the first thickness (Ti), a thickness of the film layer 14, and a thickness of the adhesive layer 16, is less than or equal to a maximum transmission thickness value. The maximum transmission thickness value may correspond to a maximum thickness of the first region 34 of the glass- based substrate 12, the film layer 14, and the adhesive layer 16 for enabling sufficient transmission of ultrasonic signals generated by the sensor 26 (e.g., 0.6 millimeters). Furthermore, a second summation value, which is a sum of the second thickness (T2), the thickness of the film layer 14, and the thickness of the adhesive layer 16, is greater than the first summation value and greater than or equal to a minimum thickness value. The minimum thickness value may correspond to a minimum thickness of the second region 36 of the glass- based substrate 12, the film layer 14, and the adhesive layer 16 such that the display protector assembly 10-1 has sufficient mechanical robustness (e.g., 0.8 millimeters).

[0086] While the thickness of the glass-based substrate 12 of the display protector assembly 10-1 gradually increases from the first thickness (T 1) to the second thickness (T2) in this embodiment, in some embodiments, the thickness of the glass-based substrate 12 may non-gradually increase or decrease from the first thickness (Ti) to the second thickness (T2). For example, the thickness of the glass-based substrate may increase or decrease from the first thickness to the second thickness in a step manner described below in further detail with reference to FIGS. 7A, 7B, 8A, and 8B.

[0087] Referring now to FIGS. 7A and 7B, a perspective view and a partial cross-section view along 7B-7B, respectively, of an example display protector assembly 10-2 disposed on the electronic device 20 are schematically depicted. In the illustrated embodiment, the glass- based substrate 12 of the display protector assembly 10-2 is selectively thinned on the upper surface 12D. Further, a thickness of the glass-based substrate 12 of the display protector assembly 10-2 non-gradually increases (e.g., in a step manner) from a first thickness (Ti) to a second thickness (T2) via the transition region 38, as described below in further detail. In some embodiments, the non-gradual increase from the first thickness (Ti) to the second thickness (T2) may provide tactile feedback that assists a user in determining where the sensor 26 is positioned within the electronic device 20. [0088] In the illustrated embodiment, the glass-based substrate 12 includes the central portion 12A and the edge portion 12B, which is disposed on a perimeter of the central portion 12A. The central portion 12A includes the first region 34, the second region 36, and the transition region 38 located between the first region 34 and the second region 36. As a non-limiting example, the first region 34 of the central portion 12A is aligned with the sensor 26 of the electronic device 20. The first region 34 of the central portion 12A has the first thickness (Ti), and the second region 36 of the central portion 12A has the second thickness (T2) such that the first thickness is less than the second thickness. The first thickness (Ti) may be less than the second thickness (T2) such that a user can place his or her finger within the working distance of the sensor 26. The second thickness (T2) may be a value that enables the display protector assembly 10-2 to have a sufficient mechanical robustness.

[0089] As illustrated in the embodiment, the transition region 38 includes a first step region end 46, a second step region end 48, and a step region 50. The first step region end 46 is proximate to the first region 34 of the central portion 12A, and the second step region end 48 is proximate to the second region 36 of the central portion 12A. As a non-limiting example, the first step region end 46 may be proximate to a region of the central portion 12A in which the slope of the central portion 12A changes from zero to a non-zero value. As another non limiting example, the second step region end 48 may be proximate to a region of the central portion 12A in which the slope of the central portion 12A changes from a non-zero value to zero. Furthermore, a thickness of the transition region 38 may increase from the first step region end 46 to the second step region end 48.

[0090] In the illustrated embodiment, at least a portion of the step region 50 is perpendicular to at least one of the first region 34 of the central portion 12A and the second region 36 of the central portion 12A. As a non-limiting example, the step region 50 is perpendicular to both the first region 34 and the second region 36 of the central portion 12A, and end portions 54, 56 of the step region 50 are neither perpendicular to the first region 34 nor perpendicular to the second region 36 of the central portion 12A. Furthermore, while end portions 54, 56 are schematically depicted as having a fillet geometry in order to prevent a user from contacting a sharp edge of the glass-based substrate 12, the end portions 54, 56 may have other geometries, such as a chamfer geometry or an edge geometry.

[0091] In the illustrated embodiment, the first summation value, which is a sum of the first thickness (Ti), a thickness of the film layer 14, and a thickness of the adhesive layer 16, is less than or equal to a maximum transmission thickness value. The maximum transmission thickness value may correspond to a maximum thickness of the first region 34 of the glass- based substrate 12, the film layer 14, and the adhesive layer 16 for enabling sufficient transmission of ultrasonic signals generated by the sensor 26 (e.g., 0.6 millimeters). Furthermore, the second summation value, which is a sum of the second thickness (T2), the thickness of the film layer 14, and the thickness of the adhesive layer 16, is greater than the first summation value and greater than or equal to a minimum thickness value. The minimum thickness value may correspond to a minimum thickness of the second region 36 of the glass- based substrate 12, the film layer 14, and the adhesive layer 16 such that the display protector assembly 10-2 has sufficient mechanical robustness (e.g., 0.8 millimeters).

[0092] While the above embodiments illustrated in FIGS. 6A, 6B, 7A, and 7B depict the selective thinning implemented on the upper surface 12D, in some embodiments, the selective thinning may be implemented on the lower surface 12C. For example and as illustrated in FIGS. 8A and 8B, the selective thinning of the glass-based substrate 12 is implemented on the lower surface 12C. Selectively thinning the glass-based substrate 12 on the lower surface 12C and depositing a filler material (shown below) between the lower surface 12C and the film layer 14 reduces the impact of acoustic interference between the user’s finger and the sensor 26, thereby improving the transmission of ultrasonic signals generated by the sensor 26. Furthermore, selectively thinning the glass-based substrate 12 on the lower surface 12C enables the display protector assembly 10 to have a sufficient mechanical robustness for preventing damage to the electronic device 20 caused by impact forces or dynamic loading.

[0093] Referring now to FIGS. 8A and 8B, a perspective view and a partial cross-section view along 8B-8B, respectively, of an example display protector assembly 10-3 disposed on the electronic device 20 are schematically depicted. In the illustrated embodiment, the glass- based substrate 12 of the display protector assembly 10-3 is selectively thinned on the lower surface 12C. In the illustrated embodiment, a thickness of the glass-based substrate 12 of the display protector assembly 10-3 non-gradually increases from a first thickness (Ti) to a second thickness (T2) via the transition region 38. The second thickness (T2) may be a value that enables the display protector assembly 10-3 to have a sufficient mechanical robustness. Furthermore, in the first region 34, a filler material 58 is disposed between the lower surface 12C of the glass-based substrate 12 and the film layer 14 in order to improve the acoustic transmission and minimize the acoustic interference of the ultrasonic signals generated by the sensor 26, as described in more detail below.

[0094] As illustrated in the embodiment, the glass-based substrate 12 includes the central portion 12A and the edge portion 12B, which is disposed on a perimeter of the central portion 12A. The central portion 12A includes the first region 34, the second region 36, and the transition region 38 located between the first region 34 and the second region 36. As a non-limiting example, the first region 34 of the central portion 12A is aligned with the sensor 26 of the electronic device 20 (not shown). In the illustrated embodiment, the first region 34 of the central portion 12A has a first thickness (Ti), and the second region 36 of the central portion 12A has a second thickness (T2), wherein the first thickness is less than the second thickness. The first thickness (Ti) may be less than the second thickness (T2) such that the filler material 58 can be disposed between the glass-based substrate 12 and the film layer 14.

[0095] The transition region 38 includes the first step region end 46, the second step region end 48, and the step region 50. The first step region end 46 is proximate to the first region 34 of the central portion 12A, and the second step region end 48 is proximate to the second region 36 of the central portion 12A. As a non-limiting example, the first step region end 46 may be proximate to a region of the central portion 12A in which the slope of the central portion 12A changes from zero to a non-zero value. As another non-limiting example, the second step region end 48 may be proximate to a region of the central portion 12A in which the slope of the central portion 12A changes from a non-zero value to zero. Furthermore, a thickness of the transition region 38 increases from the second step region end 48 to the first step region end 46.

[0096] As illustrated in the example embodiment, at least a portion of the step region 50 is perpendicular to at least one of the first region 34 of the central portion 12A and the second region 36 of the central portion 12A. As shown in FIG. 8B, the step region 50 is perpendicular to both the first region 34 and the second region 36 of the central portion 12A, and the end portion 54 of the step region 50 is neither perpendicular to the first region 34 nor perpendicular to the second region 36 of the central portion 12A. Furthermore, while the end portion 54 is schematically depicted as having a fillet geometry, the end portion 54 may have any suitable geometry, such as chamfer geometry or edge geometry. [0097] While the illustrated embodiment illustrates the thickness of the glass-based substrate 12 of the display protector assembly 10-3 non-gradually increasing from the first thickness (Ti) to the second thickness (T2) via the transition region 38, in some embodiments, the thickness may gradually increase from the first thickness (Ti) to the second thickness (T2) via the transition region 38 (e.g., the transition region 38 has a slope, the transition region 38 includes a plurality of gradual step increases from the first thickness (Ti) to the second thickness (T2), etc.).

[0098] As stated above, the display protector assembly 10-3 may include the filler material 58, which is configured to transmit ultrasonic waves generated by the sensor 26. In some embodiments, the filler material 58 may include one or more optically clear layers that are transparent in the visible spectrum (i.e., wavelengths of 380-740 nanometers, including endpoints) and may be cured using an ultra-violet (UV) light wave. As a non-limiting example, the filler material 58 may include a polyethylene terephthalate (PET) material, a liquid silicone rubber (LSR), a polycarbonate material, an acrylic material, and/or any other suitable transparent polymer in the visible spectrum. As another non-limiting example, the filler material 58 may be an adhesive film. In some embodiments, the filler material 58 may be the same material as the adhesive layer 16. Furthermore, the filler material 58 may be aligned with the sensor 26 of the electronic device 20 (not shown). In some embodiments, the filler material 58 may extend the working distance of the sensor 26.

[0099] In the illustrated embodiment, a sum of the first thickness (Ti), a thickness of the filler material 58, a thickness of the film layer 14, and a thickness of the adhesive layer 16 is greater than or equal to 0.45 millimeters and less than or equal to 0.8 millimeters. Furthermore, a sum of the first thickness and the thickness of the filler material 58 may be equal to the second thickness (i.e., the thickness of the second region 36 of the central portion 12A) . In some embodiments, a sum of the second thickness (T2), the thickness of the film layer 14, and the thickness of the adhesive layer 16 is equal to the sum of the first thickness, the thickness of the filler material 58, the thickness of the film layer 14, and the thickness of the adhesive layer 16.

[00100] While the filler material 58 is depicted as disposed between the lower surface 12C of the glass-based substrate 12 and the film layer 14 in the display protector assembly 10-3, in some embodiments, the filler material 58 maybe disposed on the upper surface 12D of the glass-based substrate 12. For example, the filler material 58 may be disposed on the upper surface 12D of display protector assemblies 10-1, 10-2, which are illustrated above in FIGS. 6A, 6B, 7A, and 7B. Moreover, if the filler material 58 is disposed on the upper surface 12D, the display protector assemblies 10-1, 10-2 may include a material that encapsulates the filler material 58, such as a glass-based material.

[00101] Furthermore, while the above embodiments illustrate the selective thinning being implemented on the first region 34 of the central portion 12A, in some embodiments, the entire central portion 12A may be selectively thinned. As an example and as described below in further detail with reference to FIGS. 9A and 9B, the central portion 12A may be thinner than the edge portion 12B. Accordingly, the user may place his or her finger within the working distance of the sensor 26, regardless of where the sensor 26 is aligned with respect to the central portion 12A. Furthermore, thinning the central portion 12A while keeping the edge portion 12B relatively thick enables the display protector assembly 10 to have a sufficient mechanical robustness for preventing damage to the electronic device 20 caused by impact forces or dynamic loading. [00102] Referring now to FIGS. 9A and 9B, a perspective view and a partial cross-section view along 9B-9B, respectively, of an example display protector assembly 10-4 disposed on the electronic device 20 are schematically depicted. The glass-based substrate 12 includes the central portion 12A, the edge portion 12B, and a transition portion 60. The edge portion 12B may be disposed on the perimeter of the transition portion 60, and the transition portion 60 may be disposed on a perimeter of the central portion 12A. Furthermore, the transition portion 60 may be located between the edge portion 12B and the central portion 12A. In some embodiments, the central portion 12A has a first thickness (Ti), the edge portion 12B has a second thickness (T2), and the first thickness is less than the second thickness. For example, the second thickness is greater than or equal to 0.2 millimeters and less than or equal to 1 millimeter (e.g., 0.4 millimeters). The first thickness (Ti) may be less than the second thickness (T2) such that a user can place his or her finger within the working distance of the sensor 26. The second thickness (T2) may be a value that enables the display protector assembly 10-4 to have a sufficient mechanical robustness.

[00103] In some embodiments, the transition portion 60 includes a first end 61 and a second end 62. The first end 61 is proximate to the central portion 12A, and the second end 62 is proximate to the edge portion 12B. As a non-limiting example, the first end 61 may be proximate to a region of the central portion 12A in which the thickness changes from the first thickness (Ti) to a thickness greater than the first thickness (Ti). As another non-limiting example, the second end 62 may be proximate to a region of the edge portion 12B in which the thickness of the glass-based substrate 12 changes to the second thickness (T2). As shown in the illustrated embodiment, a thickness of the transition portion 60 gradually increases from the first end 61 to the second 62. [00104] In some embodiments, the first summation value, which is the sum of the first thickness (Ti), the thickness of the film layer 14, and the thickness of the adhesive layer 16, is less than or equal to 0.6 millimeters (e.g., 0.45 millimeters). Furthermore, the second summation value, which is a sum of the second thickness (T2), the thickness of the film layer 14, and the thickness of the adhesive layer 16, is greater than the first summation value and less than or equal to 0.8 millimeters. In some embodiments, the first summation value and the second summation value may be any suitable value that enables the display protector assembly 10-4 to transmit ultrasonic signals and simultaneously have sufficient mechanical robustness.

[00105] While the above embodiments illustrate setting the first thickness of the glass-based substrate 12 (Ti) to be less than the second thickness of the glass-based substrate 12 (T2) such that a user can place his or her finger within the working distance of the sensor 26, in some embodiments, a first thickness of the first region 34 (ΊU, which is shown in FIGS. 10A, 10B, and, IOC) may be less than a second thickness (T2’, which is shown in FIGS. 10A, 10B, and IOC) of the second region 36 in response to the user applying a force to the glass-based substrate 12. As an example and as described below in further detail with reference to FIGS. 10A, 10B, and IOC, the glass-based substrate 12 may bend in response to the user applying a force, thereby compressing at least one of the adhesive layer 16 and the film layer 14 and enabling the user to bring his or her finger within the working distance of the sensor 26 while enabling the glass-based substrate 12 to have a sufficient mechanical robustness.

[00106] Referring now to FIGS. 10A, 10B, and IOC, a perspective view and partial cross- section views along 1 OB-10B and IOC- IOC of an example display protector assembly 10-5 disposed on the electronic device 20 are schematically depicted. The glass-based substrate 12 includes the central portion 12A and the edge portion 12B, which is disposed on a perimeter of the central portion 12A. In the illustrated embodiment, the central portion 12A includes the first region 34, the second region 36, and the transition region 38 (not shown) located between the first region 34 and the second region 36. Furthermore, the transition region 38 may have any of the characteristics described above with reference to FIGS. 6A, 6B, 7A, 7B, 8 A, and 8B. As a non-limiting example, the first region 34 of the central portion 12A is aligned with the sensor 26 of the electronic device 20 (not shown). In some embodiments, the glass-based substrate 12 includes the edge portion 12B, the transition portion 60, and the central portion 12A with a uniform thickness, as described above with reference to FIGS. 9A and 9B.

[00107] In the illustrated embodiment, the first region 34 of the central portion 12A has a first thickness (TV), the second region 36 of the central portion 12A has a second thickness (T2’),, and the first thickness is less than the second thickness. The first thickness (ΊU) may be less than the second thickness (T2’) such that a user can place his or her finger within the working distance of the sensor 26. The second thickness (T2’) may be a value that enables the display protector assembly 10-5 to have a sufficient mechanical robustness.

[00108] In the illustrated embodiment, bending regions 66 are formed in the first region 34 in response to the first region 34 receiving an external force, such as when a user applies a force with his or her finger 70 on the first region 34. Accordingly, glass-based substrate 12 may have a thickness that enables the glass-based substrate 12 to flex at the bending regions 66 in response to receiving an external force from the user’s finger 70. Furthermore, the adhesive layer 16 may include an adhesive material that compresses and thereby enables the user to bend at least a portion of the first region 34 while applying a force with his or her finger 70. When the bending regions 66 are formed, a distance between the sensor 26 and the user’s finger 70 is minimized, thereby enabling the display protector assembly 10-5 to efficiently transmit ultrasonic waves.

[00109] While FIGS. 10A, 10B, and IOC illustrate forming the bending regions 66 in response to the external force, in some embodiments, the bending regions 66 may be permanently formed in the glass-based substrate 12, as described below in further detail with reference to FIGS. 11A, 11B, and 11C.

[00110] Referring now to FIGS. 11A, 11B, and 11C, a perspective view and partial cross- section views along 11B-11B and 11C-11C of an example display protector assembly 10-6 disposed on the electronic device 20 are schematically depicted. The glass-based substrate 12 includes the central portion 12A and the edge portion 12B, which is disposed on a perimeter of the central portion 12A. In the illustrated embodiment, the central portion 12A includes the first region 34, the second region 36, and the transition region 38 (not shown) located between the first region 34 and the second region 36. Furthermore, the transition region 38 may have any of the characteristics described above with reference to FIGS. 6A-, 6B, 7A, 7B, 8A, and 8B. As a non-limiting example, the first region 34 of the central portion 12A is aligned with the sensor 26 of the electronic device 20 (not shown). In some embodiments, the glass-based substrate 12 includes the edge portion 12B, the transition portion 60, and the central portion 12A with a uniform thickness, as described above with reference to FIGS. 9A and 9B.

[00111] In the illustrated embodiment, the central portion 12A includes a depression 72 located between bending regions 66. As a non-limiting example, the bending regions 66 are permanently formed in the first region 34 of the central portion 12A. Furthermore, a thickness of the adhesive layer 16 underneath the depression 72 (T _AI ) may be less than a thickness of the adhesive layer at the bending regions 66 and other regions of the central portion 12A (e.g., T _A 2) . The depression 72 minimizes the distance between the sensor 26 and the user’s finger 70 when the user engages with the sensor 26, thereby enabling the display protector assembly 10-6 to efficiently transmit ultrasonic waves generated by the sensor 26.

[00112] While FIGS. 10A, 10B, IOC, 11A, 11B, and 11C illustrate the glass-based substrate 12 being configured to bend in response to an external force or having permanent bending regions, in some embodiments, the glass-based substrate 12 may not bend in response to receiving the external force. As described below in FIGS. 12A, 12B, and 12C, only the adhesive layer 16 may be configured to compress in response to receiving the external force in some embodiments.

[00113] Referring now to FIGS. 12A, 12B, and 12C, a perspective view and partial cross- section views along 12B-12B of an example display protector assembly 10-7 disposed on the electronic device 20 are schematically depicted. The glass-based substrate 12 includes the central portion 12A, the edge portion 12B, and the transition portion 60. The edge portion 12B and the transition portion 60 may be disposed on the perimeter of the central portion 12A, and the transition portion 60 may be located between the edge portion 12B and the central portion 12A. In some embodiments, the central portion 12A includes the first region 34, the second region 36, and the transition region 38 (not shown) located between the first region 34 and the second region 36.

[00114] As a non-limiting example, in a decompressed state, which may correspond to the absence of an external force being applied to the glass-based substrate 12, the adhesive layer 16 may have a second thickness (T _A 2), as illustrated in FIG. 12B. As another non limiting example, in a compressed state, which corresponds to a user applying a force to the glass-based substrate 12 with his or her finger 70, the adhesive layer 16 may have a first thickness (T _AI ), as illustrated in FIG. 12C. In an example embodiment, the second thickness (T _A 2) may be between 0.05 and 0.45 millimeters (e.g., 0.4 millimeters), including endpoints, and the first thickness (T _AI ) may be less than the first thickness (e.g., 0.2 millimeters).

[00115] In some embodiments, the adhesive layer 16 may include an adhesive material that compresses when the user is applying a force with his or her finger 70 (e.g., a soft adhesive material, such as a liquid optically clear adhesive). As such, in the compressed state, the user’s finger 70 can be brought within the working distance of the sensor 26. Consequently, the display protector assembly 10-7 can efficiently transmit ultrasonic waves generated by the sensor 26 while maintaining a sufficient mechanical robustness.

[00116] While some of the above embodiments illustrate the glass-based substrate 12 being selectively thinned on one of the lower surface 12C and the upper surface 12D, in some embodiments, the glass-based substrate 12 may be selectively thinned on both the lower surface 12C and the upper surface 12D, as described above.

[00117] Referring now to FIGS. 13A and 13B, a perspective view and a partial cross-section view along 13B-13B, respectively, of an example display protector assembly 10-8 disposed on the electronic device 20 are schematically depicted. In the illustrated embodiment, the glass-based substrate 12 of the display protector assembly 10-8 is selectively thinned on the lower surface 12C and the upper surface 12D. In the illustrated embodiment, a thickness of the glass-based substrate 12 of the display protector assembly 10-8 non-gradually increases on both the lower surface 12C and the upper surface 12D from a first thickness (Ti) to a second thickness (T2) via the transition region 38. The second thickness (T2) may be a value that enables the display protector assembly 10-8 to have a sufficient mechanical robustness. [00118] Furthermore, in the first region 34, the filler material 58 is disposed between the lower surface 12C of the glass-based substrate 12 and the film layer 14 in order to improve the acoustic transmission and minimize the acoustic interference of the ultrasonic signals generated by the sensor 26, as described above with reference to FIGS. 8A and 8B. In some embodiments, the selective thinning on the upper surface 12D may provide tactile feedback that assists a user in determining where the sensor 26 is positioned within the electronic device 20.

[00119] In the illustrated embodiment, the glass-based substrate 12 includes the central portion 12A and the edge portion 12B, which is disposed on a perimeter of the central portion 12A. The central portion 12A includes the first region 34, the second region 36, and the transition region 38 located between the first region 34 and the second region 36. As a non-limiting example, the first region 34 of the central portion 12A is aligned with the sensor 26 of the electronic device 20. The first region 34 of the central portion 12A has the first thickness (Ti), and the second region 36 of the central portion 12A has the second thickness (T2) such that the first thickness is less than the second thickness. The first thickness (Ti) may be less than the second thickness (T2) such that a user can place his or her finger within the working distance of the sensor 26. The second thickness (T2) may be a value that enables the display protector assembly 10-8 to have a sufficient mechanical robustness.

[00120] As illustrated in the embodiment, the transition region 38 includes a first step region end 46, a second step region end 48, and step regions 50A, 50B. The first step region end 46 is proximate to the first to the first region 34 of the central portion 12A, and the second step region end 48 is proximate to the second region 36 of the central portion 12A. As a non limiting example, the first step region end 46 may be proximate to a region of the central portion 12A in which the slope of the central portion 12A changes from zero to a non-zero value. As another non-limiting example, the second step region end 48 may be proximate to a region of the central portion 12A in which the slope of the central portion 12A changes from a non-zero value to zero. Furthermore, a thickness of the transition region 38 may increase from the first step region end 46 to the second step region end 48.

[00121] In the illustrated embodiment, at least a portion of the step regions 50A is perpendicular to at least one of the first region 34 of the central portion 12A and the second region 36 of the central portion 12A. As a non-limiting example, the step regions 50A is perpendicular to both the first region 34 and the second region 36 of the central portion 12A, and end portions 54A, 56A of the step region 50A are neither perpendicular to the first region 34 nor perpendicular to the second region 36 of the central portion 12A. Furthermore, while end portions 54A, 56A are schematically depicted as having a fillet geometry in order to prevent a user from contacting a sharp edge of the glass-based substrate 12, the end portions 54A, 56A may have other geometries, such as a chamfer geometry or an edge geometry.

[00122] Furthermore, at least a portion of the step region 50B is perpendicular to at least one of the first region 34 of the central portion 12A and the second region 36 of the central portion 12A. As shown in FIG. 13B, the step region 50B is perpendicular to both the first region 34 and the second region 36 of the central portion 12A, and the end portion 54B of the step region 50B is neither perpendicular to the first region 34 nor perpendicular to the second region 36 of the central portion 12A. Furthermore, while the end portion 54B is schematically depicted as having a fillet geometry, the end portion 54B may have any suitable geometry, such as chamfer geometry or edge geometry. It should be understood that the end portion 54B may have different alignments and/or configurations in other embodiments. [00123] In the illustrated embodiment, the first summation value, which is a sum of the first thickness (Ti), a thickness of the film layer 14, a thickness of the filler material 58, and a thickness of the adhesive layer 16, is less than or equal to a maximum transmission thickness value. The maximum transmission thickness value of the first region 34 may correspond to a maximum thickness of the first region 34 of the glass-based substrate 12, the film layer 14, and the adhesive layer 16 for enabling sufficient transmission of ultrasonic signals generated by the sensor 26 (e.g., 0.6 millimeters). Furthermore, the second summation value, which is a sum of the second thickness (T2), the thickness of the film layer 14, and the thickness of the adhesive layer 16, is greater than the first summation value and greater than or equal to a minimum thickness value . The minimum thickness value may correspond to a minimum thickness of the second region 36 of the glass-based substrate 12, the film layer 14, and the adhesive layer 16 such that the display protector assembly 10-2 has sufficient mechanical robustness (e.g., 0.8 millimeters).

[00124] While the illustrated embodiment depicts a magnitude of selective thinning of the upper surface 12D and the lower surface 12C as equal, in other embodiments, the magnitude of selective thinning of the upper surface 12D and the lower surface 12C may be unequal. In other words, the step region 50A may have a thickness that is unequal to the thickness of the step region 50B. Furthermore, while the illustrated embodiment depicts the thickness of the glass-based substrate 12 non-gradually increasing from the first thickness (Ti) to the second thickness (T2) on both the upper surface 12D and the lower surface 12C, in other embodiments, the thickness of the glass-based substrate 12 may gradually increase on at least one of the upper surface 12D and the lower surface 12C.

[00125] As described in the above embodiments, by selectively thinning the glass-based substrate 12 of the display protector assembly 10, the distance between the sensor 26 and the glass-based substrate 12 is minimized, thereby enabling a user to bring his or her finger within the working distance of the sensor 26. Furthermore, by selectively thinning the glass- based substrate 12 of the display protector assembly 10, the amount of acoustic interference between the user’s finger and the sensor 26 is minimized, thereby improving the functionality of the sensor 26 and the accuracy of the authentication algorithms executed by the electronic device 20.

[00126] Additionally and as described above, the areas of the glass-based substrate 12 that are not aligned with the sensor 26 of the electronic device 20 may not be thinned. Therefore, these non-thinned areas of the glass-based substrate 12 may enable the display protector assembly 10 to have a sufficient thickness that prevents the cover glass 22 from being damaged in response to impact forces or dynamic loading to the display protector assembly 10.

[00127] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosure. Since modifications, combinations, sub -combinations and variations of the disclosed embodiments incorporating the spirit and substance of the disclosure may occur to persons skilled in the art, the disclosure should be construed to include everything within the scope of the appended claims and their equivalents.