CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian patent application no. 102018000004931 filed on 27/04/2018, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a multi-COB-LED lighting module .

PRIOR ART

The use of LEDs as lighting sources is becoming increasingly widespread due to the many advantages, compared to traditional incandescent and fluorescent lamps, mainly with regard to consumption, versatility and control flexibility, which allows the creation of the most varied effects. In fact, LEDs are frequently used for indoor and outdoor lighting. Among the many uses, for example, LEDs can be advantageously exploited for street lighting and for the illumination of monuments and architectural structures, in the entertainment field for the production of stage lights (both for effects and for making Wash Light type projectors) . In interiors, LEDs are often preferred even for home lighting.

It is also known that COB-LED lighting modules, made using the so-called "Chips On Board" technology, are particularly successful in the lighting field. The COB-LED lighting modules generally comprise a common supporting layer (hereinafter referred to as "COB-submount" ) and a plurality of clusters of LED-chips which are housed on the supporting layer according to a geometric matrix distribution and are adapted, in use, to emit light radiation in respective emission bands associated with corresponding lights of colours different from one another.

The COB-LED lighting modules described above have numerous advantages which include: having a particularly compact light emitting surface (Light Emitting Surface - LES), allowing the light colour to be adjusted within a relatively large range of colour shades, and to perform a pre-mixing of the coloured lights already in the emission phase of the same by means of the LED- chips thanks to the uniform distribution of the latter.

Despite the numerous advantages described above, currently there is a technical need to be able to further increase the pre mixing of the coloured lights by means of the COB-LED lighting modules without, however, affecting the compactness of the light emitting surface of the modules.

DESCRIPTION OF THE INVENTION

The object of the present invention is to provide a multi- LED lighting module based on COB technology, which allows to increase the pre-mixing of the light already at the emission time by means of the LED-chips without compromising the compactness of the light emitting surface.

According to these objectives, in accordance with the present invention a multi-COB-LED lighting module is provided comprising: a submount, a plurality of clusters of LED-chips which are designed to emit light radiation in respective emission bands, each LED-chip cluster comprises a plurality of LED-chips which are arranged on said submount by means of a chip on board technology and are designed to emit light radiation in respective emission bands, the LED-chips belonging to a same LED-chip cluster are grouped together so as to form at least two adjoining rows of LED-chips on said submount, at least an LED- chip cluster designed to emit light radiation in a first emission band adjoined by at least three clusters of LED-chips which are designed to emit light radiation in emission bands other than said first emission band.

Preferably, at least one of the LED-chips of an LED-chip cluster associated with said first emission band is connected to an LED- chip of another LED-chip cluster associated with said first emission band, by one or more wire bonds extending above one or more LED-chips of said at least three different adjoining clusters of LED-chips.

Preferably, said LED-chips are arranged on said submount adjacent one to the other in order to approximately form an LED- chip matrix, each LED-chip comprises one or more top connection terminals and at least one bottom connection terminal, at least one top terminal of an LED-chip of an LED-chip cluster associated with said first emission band is connected to a bottom terminal of an LED-chip of another LED-chip cluster associated with said first emission band by means of a wire bond, which extends above one or more of said adjoining clusters of LED-chips.

Preferably, said at least one top terminal is arranged on the top surface of the LED-chip, and said bottom terminal protrudes from a side of said LED-chip.

Preferably, at least a top/bottom terminal of an LED-chip is adjacent to a bottom/top terminal of another LED-chip.

Preferably, the clusters of LED-chips comprise five or more of the following clusters of LED-chips: a) an LED-chip cluster comprising a plurality of direct emission blue LED-chips, or b) an LED-chip cluster comprising a plurality of direct emission cyan LED-chips, or c) an LED-chip cluster comprising a plurality of direct emission green LED-chips, or an LED-chip cluster comprising a plurality of direct emission red LED-chips, and or) an LED-chip cluster comprising a plurality of phosphor-converted amber LED-chips, or f) an LED-chip cluster comprising a plurality of phosphor-converted lime LED-chips, or g) an LED- chip cluster comprising a plurality of direct emission aquamarine LED-chips, or h) an LED-chip cluster comprising a plurality of direct emission or phosphor-converted deep red LED- chips, or i) an LED-chip cluster comprising a plurality of direct emission or phosphor-converted deep blue LED-chips, or 1) an LED-chip cluster comprising a plurality of warm white light LED- chips, or m) an LED-chip cluster comprising a plurality of cold white LED-chips; or n) an LED-chip cluster comprising a plurality of UV-A LED-chips, or o) an LED-chip cluster comprising a plurality of UV-B LED-chips, or p) an LED-chip cluster comprising a plurality of UV-C LED-chips or q) an LED- chip cluster comprising a plurality of IR LED-chips.

Preferably, said first LED-chip cluster comprises one of the following clusters of LED-chips: a) an LED-chip cluster comprising a plurality of direct emission blue LED-chips, or b) an LED-chip cluster comprising a plurality of direct emission cyan LED-chips, or c) an LED-chip cluster comprising a plurality of direct emission green LED-chips, or d) an LED-chip cluster comprising a plurality of direct emission red LED-chips, or e) an LED-chip cluster comprising a plurality of phosphor-converted amber LED-chips, or f) an LED-chip cluster comprising a plurality of phosphor-converted lime LED-chips, or g) an LED- chip cluster comprising a plurality of direct emission aquamarine LED-chips, or h) an LED-chip cluster comprising a plurality of direct emission or phosphor-converted deep red LED- chips, or i) an LED-chip cluster comprising a plurality of direct emission or phosphor-converted deep blue LED-chips, or 1) an LED-chip cluster comprising a plurality of warm white LED-chips, or m) an LED-chip cluster comprising a plurality of cold white LED-chips, or n) an LED-chip cluster comprising a plurality of UV-A LED-chips, or o) an LED-chip cluster comprising a plurality of UV-B LED-chips, or p) an LED-chip cluster comprising a plurality of UV-C LED-chips or q) an LED-chip cluster comprising a plurality of IR LED-chips.

Preferably, the LED-chips belonging to a same LED-chip cluster are electrically connected one to the other by means of said wire bonds according to a series/parallel configuration. Preferably, said LED-chips are quadrangular, preferably square, hexagonal or rhomboidal shaped.

Preferably, said LED-chips (4) have dimensions ranging between approximately 0.58 mm X 0.58 mm (20 X 20 mils) and approximately 1.43 mm X 1.43 mm (45 X 45 mils) .

Preferably, the bottom surface and/or the top surface of the submount is approximately flat.

Preferably, the bottom surface and/or the top surface of the submount is curved, concave or convex.

Preferably, the submount has a circular shape.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the annexed drawings, which illustrate a non-limiting embodiment, wherein:

- Figure 1 is a simplified front view, with parts enlarged for clarity, of a multi-COB-LED lighting module obtained according to the dictates of the present invention;

- Figure 2 is a simplified section view of a portion of the multi-COB-LED lighting module shown in Figure 1;

- Figure 3 is a simplified front view with parts enlarged for clarity, of a portion of the multi-COB-LED lighting module obtained according to a possible embodiment of the present invention;

- Figure 4 is a simplified front view of a multi-COB-LED lighting module obtained according to a possible embodiment of the present invention;

- Figure 5 is a simplified perspective view of a portion of a multi-COB-LED lighting module obtained according to a possible alternative embodiment of the present invention. PREFERRED EMBODIMENTS OF THE INVENTION

The present invention will now be described in detail with reference to the attached figures to allow a person skilled in the art to make and use it. Various modifications to the described embodiments will become immediately apparent to the person skilled in the art and the generic principles described can be applied to other embodiments and applications without thereby departing from the scope of the present invention, as defined in the attached claims. Therefore, the present invention should not be considered limited to the described and illustrated embodiments, but the broader protective scope must be conferred according to the principles and characteristics described and claimed herein.

With reference to Figure 1, number 1 denotes as a whole a multi- COB-LED lighting module obtained by using the chips on board technology, whose acronym, used in the following, is "COB".

The multi-COB-LED lighting module 1 comprises a submount 2, and a plurality of clusters of LED-chips arranged on the submount 2 according to the configurations described in the following. The clusters of LED-chips are adapted to emit, in use, light radiation in respective emission bands comprised between a plurality of predetermined emission bands described in detail in the following.

Each LED-chip cluster comprises, in turn, a plurality of LED light sources consisting of respective LED-chips 4, which are stably coupled/housed with/in the submount 2 by means of the COB technology. The LED-chips 4 belonging to one or more each LED- chip cluster are adapted to emit, in use, light radiation in the same predetermined emission band, by means of respective emitting areas.

According to a preferred embodiment shown in Figures 1, 2 and 3, the submount 2 ( substrate/submount ) can have a bottom surface 2a and an opposite top surface 2b, on which the bases or bottom surfaces 4a of the LED-chips 4 are stably arranged.

According to a preferred embodiment shown in Figures 1, 2 and 3, the bottom surface 2a and/or the top surface 2b of the submount 2 is approximately flat. However, it is understood that according to other embodiments (not illustrated) , the top surface 2b of the submount 2 can be curved, for example concave or convex. It is also understood that the geometric shape of the submount 2 depends on the lighting device on which the multi- COB-LED lighting module 1 is installed. In the examples shown in the accompanying figures, the submount 2 has a circular shape. The submount 2 can be made, for example, of a ceramic material.

It is, however, to be understood that the present invention should not be considered limited to a submount of circular geometric shape and/or made of a ceramic material, but may provide both different alternative geometric shapes, for example rectangular or hexagonal, and the use of different materials, such as alumina or aluminium nitride (AIN) .

With reference to Figures 2 and 3, the LED-chips 4 can each comprise a top surface 4b, opposite the bottom surface 4a, which comprises the aforementioned emitting area.

According to a preferred embodiment shown in the accompanying Figures, the LED-chips 4 can conveniently have an approximately quadrangular shape, preferably square. It should, however, be understood that the present invention should not be considered limited to the use of LED-chips 4 having a square or rectangular shape. In other embodiments, the LED-chips 4 can be hexagonal allowing a tessellation of the honeycomb-shaped submount 2, or alternatively, rhombus-shaped allowing a tessellation of the Penrose submount 2, or they can be approximately circular.

The LED-chips 4 can comprise, for example, micro-LEDs (pLED) and/or regular chips. For example, micro-LEDs (pLED) can have dimensions ranging between approximately 0.58 mm X 0.58 mm (20X20 mils) and approximately 1.43 mm X 1.43 mm (45 X 45 mils) .

In the preferred embodiments illustrated, the LED-chips 4 of the multi-COB-LED lighting module 1 can have the same dimensions. In other embodiments, the LED-chips 4 can however have different dimensions from one another.

With reference to Figure 1, the LED-chips 4 are housed on the top surface 2b of the submount 2 in order to approximately form a matrix of rows and columns. The LED-chips 4 are arranged adjacent one to the other in a substantially contiguous manner, but remaining electrically isolated from one another.

According to one aspect of the present invention, the LED-chips 4 arranged along the rows and the columns of the matrix have the sides approximately parallel to, but slightly misaligned (offset) with respect to, the corresponding sides of the adjacent LED-chips 4, and delimit with the same, preferably in clusters of four LED-chips 4, free portions (not illustrated) on the top surface 2b of the submount 2.

According to a preferred embodiment shown in the accompanying figures, each LED-chip 4 is provided with at least one first and at least one second external electrical connection terminal, both in view. One of the two terminals is electrically connected to the anode of the LED-chip 4 and the other terminal is electrically connected to the cathode of the LED-chip 4.

According to an aspect of the invention, one of the two terminals, indicated hereinafter with top terminal 4c, is arranged on the top surface 4b of the LED-chip 4 preferably approximately the external perimeter edge, preferably approximately at a first vertex of the square formed by the meeting point of a first and a second side of the LED-chip 4. The other terminal of the LED-chip 4, indicated hereinafter with bottom terminal 4d, is arranged on the bottom surface 4a of the LED-chip 4 preferably at a second vertex of the square, diagonally opposite relative to the first vertex, and formed by the meeting point of a third and fourth side of the LED-chip 4.

The bottom terminal 4d can be conveniently shaped so as to project from a side of the LED-chip 4 and can be sized so as to occupy said free portion (not illustrated) present on the top surface 2b of the submount 2 delimited by the four adjacent LED- chips 4. According to one aspect of the invention, the bottom terminal 4d can have a reduced thickness, i.e. being approximately laminar, and preferably have an approximately quadrangular, preferably square, perimetral shape.

According to an exemplary embodiment, the bottom terminal 4d can be shaped so as to extend, at least partially, on the bottom surface 4a of the LED-chip 4 and/or it can be part of a layer of conductive material present on the submount 2 on which the bottom surface 4a of the LED-Chip 4 is fixed.

The aforementioned matrix arrangement of the LED-chips 4 along the rows and columns, slightly offset in pairs, allows, on the one hand, to arrange the second bottom terminal 4d between the LED-chips 4 keeping it in view and, on the other hand, to optimize the area of occupation of the submount 2 by means of the LED-chips 4, thus maintaining a high compactness of the light emitting surface (LES) of the multi-COB-LED lighting module 1.

According to a preferred embodiment shown in Figure 1, the matrix of LED-chips 4 is structured so that each LED-chip 4 is adjoined by, and surrounded by, a plurality of LED-chips 4, and has the first and/or or the second terminal, which is arranged adjacent to the second and/or to the first terminal of an adjacent LED- chip/s 4, respectively. It should be understood that the number of adjacent LED-chips 4 which adj oin/surround an LED-chip 4 can vary as a function of the position of the LED-chip 4 in the matrix. For example, in the accompanying Figures, the external LED-chips 4, i.e. arranged in the outer perimeter rows/columns of the matrix, can adjoin with an adjacent number of LED-chips 4 preferably ranging between three and six, and have a first terminal adjacent to the second terminal of an adjacent LED- chip 4. As regards, instead, the internal LED-chips 4, arranged on the internal rows/columns of the matrix, they can adjoin with eight adjacent LED-chips 4. The internal LED-chips 4 can each have the bottom terminal and the top terminal which are adjacent to the top terminal and to the bottom terminal, respectively, of two different LED-chips 4, set next to the LED-chip 4.

According to a possible embodiment shown in Figure 1, the LED- chips 4 are arranged on the submount 2 so that they all have the same side, for example the first side, facing a common side of the multi-COB-LED module 1, and that the respective first terminals have the same orientation. Figure 1 shows an example in which the LED-chips 4 have the respective first sides and the top terminals 4c accordingly arranged one with the other (facing the top side of the sheet in Figure 1) .

It should, however, be understood that according to other embodiments, the LED-chips 4 can have a mutually different orientation .

With reference to some preferred embodiments shown in the accompanying Figures, the multi-COB-LED lighting module 1 can conveniently comprise six clusters of LED-chips provided with LED-chips 4 arranged in a matrix in the manner described above, adapted to emit light radiation in six respective emission bands. Preferably, the six clusters of LED-chips can comprise, for example, by choice:

a) an LED-chip cluster comprising a plurality of direct emission blue LED-chips; b) an LED-chip cluster comprising a plurality of direct emission cyan LED-chips;

c) an LED-chip cluster comprising a plurality of direct emission green LED-chips;

d) an LED-chip cluster comprising a plurality of direct emission red LED-chips;

e) an LED-chip cluster comprising a plurality of phosphor- converted amber LED-chips;

f) an LED-chip cluster comprising a plurality of phosphor- converted lime (i.e. yellow-green) LED-chips.

As mentioned above, the LED-chips 4 belonging to six clusters of LED-chips listed above emit in respective emission bands, which can be characterized in terms of dominant wavelength.

With reference to the preferred embodiments shown in the accompanying Figures, the direct emission blue LED-chips, hereinafter referred to as 4-LBD, have a dominant wavelength ranging between 443 nm and 457 nm, preferably 450 nm; the direct emission cyan LED-chips, hereinafter referred to as 4-LCD, have a dominant wavelength ranging between 478 nm and 493 nm, preferably 485 nm; the direct emission green LED-chips, hereinafter referred to as 4-LGD, have a dominant wavelength ranging between 518 nm and 532 nm, preferably 525 nm; the direct emission red LED-chips, hereinafter referred to as 4-LRD, have a dominant wavelength ranging between 621 nm and 635 nm, preferably 628 nm; the phosphor-converted amber LED-chips, hereinafter referred to as 4-LAF, have a dominant wavelength ranging between 583 nm and 597 nm, preferably 590 nm; the phosphor-converted lime LED-chips, hereinafter referred to as 4-LLF, have a dominant wavelength ranging between 563 nm and 577 nm, preferably 570 nm.

According to an aspect of the invention, the LED-chips 4 of a same LED-chip cluster are connected one to the other by means of wire bonds 5 (wire bonding) (only some of which have been shown for reasons of clarity) , which extend over the top surfaces 4b of the LED-chips 4. Each wire bond 5 connects the first terminal of an LED-chip 4 to the second terminal of another LED- chip 4.

According to a preferred embodiment shown in the accompanying figures, each wire bond 5 connects the bottom terminal 4d of an LED-chip 4 to the top terminal 4c of another LED-chip 4 belonging to the same LED-chip cluster. According to one aspect of the invention, the LED-chips 4 belonging to the same LED-chip cluster can be electrically connected one to the other by means of the wire bonds 5 preferably, but not necessarily, according to a series circuit configuration. Preferably, the serial circuit configuration can provide a single branch, several branches or independent strings of LED-chips 4 in series, and one or more electrical control channels/circuits arranged in the submount 2 (not illustrated) to selectively control the branch/es/ string/ s .

It should be understood that the present invention should not be considered limited to the configuration in series described above but could envisage other alternative circuit configurations of connection between the LED-chips 4, i.e. in parallel or in parallel/series . In some embodiments, for example, the LED-chips 4 can be connected in parallel with at least one electrical control channel/circuit. For example, 2N (number) of LED-chips 4 of the same LED-chip cluster could be divided into two branches/strings each of which could comprise N (number) of LED-chips 4.

According to a convenient aspect of the present invention shown in Figure 1, the LED-chip matrix 4 is made so that the LED-chips 4 belonging to a same LED-chip cluster are grouped together form two or more contiguous rows of LED-chips 4 on the submount 2. Preferably, one or more clusters of LED-chips are arranged on the submount 2 so as to adjoin each of them with three or more clusters of different LED-chips, i.e. adapted to emit light radiation in respective emission bands different from the emission band of the LED-chip cluster.

Preferably, the clusters of LED-chips can conveniently be arranged, one with respect to the other, on the submount 2, according to a topological distribution, whose centre is approximately coincident with the geometric centre of the light emitting surface (LES) .

It should be understood that the number of LED-chips 4 can vary depending on the sizes/shape of the multi-COB-LED lighting module 1. According to an exemplary embodiment, the number of LED-chips 4 of the multi-COB-LED lighting module 1 can range from approximately eighty to approximately ninety. It should be understood that the present invention is not limited to a number of LED-chips 4 ranging between approximately eighty to approximately ninety, but may provide other embodiments, for example in which the number of LED-chips 4 varies between approximately forty and approximately fifty.

In the exemplary embodiment shown in Figure 1, the multi-COB- LED lighting module 1 comprises, for example, eighty-eight LED- chips. The LED-chips are arranged in a matrix and belong to the six clusters of LED-chips a) -f ) listed above. Each of the LED- chips 4 belonging to the direct emission clusters of LED-chips (clusters a) , b) , c) , d) is surrounded by LED-chips 4 belonging to the other clusters of LED-chips 4. Preferably, the direct emission LED-chips 4 can be conveniently arranged on the submount, separated one from the other by the other LED-chips 4 (of different band) , according to a discrete topological distribution, whose centre is approximately coincident with the geometric centre of the light emitting surface (LES) .

According to an aspect of the invention shown in Figure 1, the adjoining rows of LED-chips 4 forming an LED-chip cluster of the module 1 can conveniently extend so as to occupy a portion of a relative quadrant of the top surface 2b of the submount 2. Preferably, the adjoining rows of LED-chips 4 of the clusters of LED-chips associated with the same emission band, can be arranged on different quadrants of the top surface 2b of the submount 2 so that their topological centre is approximately coincident with the geometric centre of the light emitting surface (LES) .

According to an aspect of the present invention, the rows of LED-chips forming an LED-chip cluster can extend adjacent to each other, preferably along parallel and/or orthogonal diagonal sections. According to an aspect of the present invention, the rows of LED-chip that form an LED-chip cluster can be sized so as to occupy a portion of area of the submount 2 whose maximum size, i.e. width or length is less than the maximum size, width or length, respectively, of the top surface 2b of the submount 2.

Preferably, the adjoining rows of LED-chips forming an LED-chip cluster can be arranged so that the two terminals 4c and 4d of the LED-chips of a row have an orientation opposite to the terminals 4c and 4d of the LED-chips of another adjoining row, along relative parallel diagonal directions. For example, as shown in Figure 4, a series of LED-chips of a cluster are arranged on a first bottom row and have the terminals 4c and 4d facing the top part of Figure 4, whereas series of 4-LGD LED- chips of the same cluster are arranged on a second top row contiguous with the first row and have the terminals 4c and 4d facing the bottom part of Figure 4. This arrangement creates an aligned and adjacent positioning of the terminals 4c and 4d of two side-by-side 4-LGD LED-chips easily connectable by means of a reduced length of connection wire 5.

According to an aspect of the invention shown in Figure 1, each of the clusters of LED-chips of the module 1 can conveniently adjoin to three or more different clusters of LED-chips. In the example shown in Figure 1, the module comprises nine clusters of LED-chips belonging to six different emission bands, some of which are surrounded by three different clusters of LED-chips. For example, as shown in the example of Figure 1, can be provided: a 4-LLF lime LED-chip cluster, a 4-LBD blue LED-chip cluster, two 4-LCD cyan clusters of LED-chips, two 4-LGD green clusters of LED-chips, a 4-LRD red LED-chip cluster, two 4-LAF amber clusters of LED-chips. It should be understood that the number of clusters of LED-chips, their arrangement and their emission bands could be different from those shown in Figure 1.

The Applicant has found that the aforesaid configuration allows, on the one hand, to simplify the layout of the lighting module 1, increasing the pre-mixing of the light already at the emission time of the LED-chips, without however affecting the compactness of the light emitting surface. Furthermore, it is conveniently possible to selectively adjust the LED-chips belonging to the same clusters by means of the respective control channels/branches. The selective management of the clusters of LED-chips associated with the same band allows to simplify the control of the heat dissipation of the lighting module. Furthermore, the selective management of the clusters of LED- chips associated with the same band allows to generate light beams of non-uniform colours (colorization) .

According to an aspect of the invention shown in Figure 1, two LED-chips 4 belonging to two respective clusters of LED-chips associated with the same emission band, for example a first predetermined band, can be conveniently electrically connected one to the other by wire bonds 5 extending above (astride) different adjoining clusters of LED-chips, that is, associated with emission bands different from the first predetermined band. Preferably, the wire bond 5 can connect the first terminal of an LED-chip 4 belonging to the LED-chip cluster associated with the first emission band, to a second terminal of the other LED- chip 4 belonging to the other LED-chip cluster associated with the first band. Conveniently, the wire bond 5 can connect the bottom terminal 4d of an LED-chip 4 to the top terminal 4c of the other LED-chip 4.

Figure 1 shows a mere non-limiting example and only to increase the exposition clarity, of only two wire bonds 5, one of which connects two LED-chips of two non-adjoining 4-LAF amber clusters of LED-chips, and the another connects two clusters of LED-chips of two non-adjoining 4-LCD cyan clusters of LED-chips.

Conveniently, in the LED-chip matrix 4 shown in the example of Figure 1, the area occupation ratios of the submount 2 by the clusters of LED-chips a) , b) c) d) , e) and f ) can be respectively :

I ) 1: 1: 1: 2: 2: 1 so as to create the respective luminous flux ratios :

I I ) 50%; 125%; 250%; 800%: 450%: 100% (+ or - 25%) .

In other words, the number of LED-chips in the 4-LAF phosphor- converted amber clusters of LED-chips and the number of LED- chips in the 4-LLF phosphor-converted lime LED-chip cluster in the multi-COB-LED module 1, could conveniently be double the number of LED-chips 4 belonging to each of the remaining four clusters of LED-chips a), b) , c) , d) listed above.

It should be understood that the present invention is not limited to the use of six clusters of LED-chips as shown in the example of Figure 1.

In fact, the Applicant has found that a number of clusters of LED-chips could conveniently be between five and eight.

It should also be understood that the present invention is not limited to clusters of LED-chips having the LED-chips operating in the emission bands described above. In this regard, the Applicant has found that it is possible to use, optionally as an alternative and/or in addition to the clusters of LED-chips from a) to f) described above, one or more of the following clusters :

g) an LED-chip cluster comprising a plurality of direct emission aquamarine LED-chips (direct aquamarines) in which the dominant wavelength can range between 495 nm and 505 nm, preferably approximately 500 nm;

h) an LED-chip cluster comprising a plurality of direct emission or phosphor-converted deep red LED-chips in which the dominant wavelength can range between 633 nm and 643 nm, preferably approximately 638 nm; and/or

i) an LED-chip cluster comprising a plurality of direct emission or phosphorus conversion deep blue LED-chips in which the dominant wavelength can range between 425 nm and 435 nm, preferably approximately 430 nm; and/or

l) an LED-chip cluster comprising a plurality of warm white LED- chips,

m) an LED-chip cluster comprising a plurality of cool white LED- chips .

It should also be understood that the present invention is not limited to clusters of LED-chips operating in the visible light spectrum. For example, the Applicant has found that one or more of the following clusters can be used, optionally as an alternative and/or in addition to the clusters of LED-chips from a) to m) described above:

n) an LED-chip cluster comprising a plurality of UV-A

(Ultraviolet A) LED-chips;

o) an LED-chip cluster comprising a plurality of UV-B

(Ultraviolet B) LED-chips;

p) an LED-chip cluster comprising a plurality of UV-C

(Ultraviolet C) LED-chips;

q) an LED-chip cluster comprising a plurality of IR (Infrared Radiation) LED-chips. It should also be understood that the present invention is not limited to the numerical ratio of area occupancy described in point I ) and/or to the luminous flux ratio of point I I ) but can provide different area and flow ratios of LED-chips 4.

In the event that there is a need to obtain a dominant warm white light effect, it may be convenient to increase the number of 4-LAF amber LED-chips and the number of 4-LRD red LED-chips, and to reduce at least the number of 4-LBD blue LED-chips, of 4-LLF lime LED-chips, 4-LGD green LED-chips, and 4-LCD cyan LED- chips .

Conversely, if there is a need to obtain a dominant effect of cold white light, it may be convenient to increase the number of at least 4-LBD blue LED-chips, the 4-LLF lime LED-chips, the 4-LGD green LED-chips, and the 4-LCD cyan LED-chips and to decrease the number of 4-LAF amber LED-chips and the 4-LRD red LED-chips .

It should be understood that the present invention is not limited to the use of LED-chips provided with a single top connection terminal 4c but can provide for the use of COB LED-chips provided with two or more top connection terminals 4c. Figure 5 shows, by way of non-limiting example, a portion of a multi-COB-LED lighting module 1, in which the LED-chips 4 are provided with two top connection terminals 4c. The two top connection terminals 4c can be preferably associated with two cathodes or with two anodes.

In the embodiment shown in Figure 5, the LED-chip matrix 4 is made so as to present at least one of the LED-chips 4 of an LED- chip cluster associated with a first emission band which adjoins the LED-chips 4 belonging to one or more clusters of LED-chips associated with emission bands different from the first. The LED-chips 4 of an LED-chip cluster associated with a first emission band is electrically connected to an LED-chip 4 belonging to another LED-chip cluster associated with a first emission band, by means of two wire bonds 5. The two wire bonds 5 extend above the LED-chips 4 of the clusters of LED-chips which adjoin the two separate clusters of LED-chips associated with the first emission band. Preferably, the two wire bonds 5 can connect, for example, the two top connection terminals 4c of the LED-chip of an LED-chip cluster with the bottom connection terminal 4d of the LED-chip 4 of the other LED-chip cluster. The multi-COB-LED lighting module allows to increase the pre mixing of the light already at the time of emission by means of the LED-chips without compromising the compactness of the light emitting surface. Finally, it is clear that modifications and variations may be made to the multi-COB-LED lighting module described above without thereby departing from the scope of the present invention defined by the appended claims.