CN221150016U - Micro-LED array chip and display device - Google Patents

Abstract

The utility model relates to a micro LED array chip and a display device, wherein the micro LED array chip comprises: a substrate; a good conductor layer and a first semiconductor layer sequentially stacked on the substrate; a light emitting array, each light emitting unit in the light emitting array comprises an active layer and a second semiconductor layer sequentially stacked on the first semiconductor layer, and each second semiconductor layer is provided with an independent first electrode; a second electrode is provided on the good conductor layer and is separated from the light emitting array. Through the solution of the application, the phenomenon of uneven display of light emitting units in different areas of the micro LED array chip can be avoided.

Description

Micro LED array chip and display device

Technical Field

The utility model relates to the field of display technology, and in particular to a micro LED array chip and a display device.

Background technique

As a new generation of green light sources, light-emitting diodes have been widely used in traffic signs, indoor and outdoor lighting, architectural decorative lighting, display backlight modules, etc. Compared with traditional light sources, LEDs have many advantages, such as environmental protection and pollution-free, short response time, longer service life, higher reliability, smaller size and higher brightness, etc. More importantly, LEDs are energy-saving and have higher efficiency. It is an inevitable trend for light-emitting diodes to replace traditional light sources and become the new generation of light sources in the future lighting and display fields. Vertical structure LEDs have become a research hotspot in the field of LED displays because of their good heat dissipation performance and uniform current expansion.

When vertical structure LEDs are applied to display devices, the two terminals of the p-pole and the n-pole are formed in each pixel through the chip manufacturing process, and then arranged along the vertical and horizontal axes of the signal line for driving. In this case, since the elements responsible for signal control of the micro LED pixels should be formed separately in the peripheral area, the size of the micro LED array display increases, and the data lines along the vertical and horizontal axes of the array should be connected to the micro LED pixels through wire bonding, which makes the process complicated and inconvenient.

To address the above problems, a LED array chip with a shared N-type semiconductor layer is currently proposed, which is then directly bonded to a CMOS backplane for driving, thereby avoiding the above problems. However, in this structure, uneven current conduction in the central area of the array causes uneven light emission in the central and peripheral areas.

Utility Model Content

In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a micro LED array chip and a display device, aiming to solve the problem of uneven display of the chip array.

An embodiment of the present application provides a micro LED array chip, comprising a substrate; a good conductor layer and a first semiconductor layer stacked in sequence on the substrate; a light-emitting array, wherein each light-emitting unit in the light-emitting array comprises an active layer and a second semiconductor layer stacked in sequence on the first semiconductor layer, and each second semiconductor layer is provided with an independent first electrode; a second electrode is provided on the good conductor layer and separated from the light-emitting array.

In the micro LED array chip provided in the embodiment of the present application, a good conductor layer is provided between the first semiconductor layer and the substrate, and the good conductor layer is directly connected to the second electrode. Thus, when the micro LED array chip is driven for display, the light emitting units in the central area (or the area far from the second electrode) of the LED array chip can directly conduct current to the first semiconductor layer around the light emitting units in the central area through the second electrode and the good conductor layer, and then pass through the active layer and the second semiconductor layer of the light emitting units to drive the light emitting units to emit light. This avoids the problem that in the conventional technology, the light emitting units in the central area (or the area far from the second electrode) of the micro LED array chip are far from the second electrode, resulting in uneven display due to excessive resistance between the light emitting units in the central area of the micro LED array chip and the second electrode when current is conducted from the second electrode to the light emitting units in the central area through the first semiconductor layer.

As an optional implementation manner, the electrical conductivity of the good conductor layer is greater than the electrical conductivity of the first semiconductor layer.

In the micro LED array chip provided in the embodiment of the present application, since the path with the least resistance is selected for current conduction, when the conductivity of the good conductor layer is greater than the conductivity of the first semiconductor layer, the current will be preferentially conducted through the good conductor layer. Therefore, the resistance of the first semiconductor layer between the second electrode and the light-emitting unit can be effectively reduced, thereby avoiding the phenomenon of uneven light emission of the light-emitting unit array in the micro LED array chip.

As an optional implementation, the good conductor layer includes at least one of Ti and Ni, and has a thickness of 3-50 nm.

As an optional implementation, the good conductor layer includes ITO and Al; wherein the thickness of ITO is 50-200 nm, and the thickness of Al is 1-5 nm.

In the embodiment of the present application, the micro LED array chip emits light from the substrate side. Therefore, in order to ensure the light extraction efficiency, the good conductor layer must have a certain transmittance and a resistivity less than a certain threshold. Therefore, in the embodiment of the present application, the material of the good conductor layer is at least one of Ti and Ni; or a composite layer structure of ITO and Al is used.

As an optional implementation manner, the second electrode is arranged on the first semiconductor layer along the periphery of the light emitting array.

As an optional implementation manner, the first electrode and the second electrode are on the same horizontal plane at one end away from the first semiconductor layer.

In the micro LED array chip provided in the embodiment of the present application, the first electrode and the second electrode are on the same horizontal plane at one end away from the first semiconductor layer, which is beneficial for bonding the micro LED array chip to the display backplane.

As an optional implementation manner, the transmittance of the good conductor layer is 65%-95%.

As an optional implementation, a light isolator is further provided between the light emitting units of the light emitting array, and the light isolator is used to isolate the light between two adjacent light emitting units.

In the micro LED array chip provided in the embodiment of the present application, in order to prevent light from crosstalk between the light emitting units, a light isolator is provided between the light emitting units of the light emitting array.

As an optional implementation manner, a passivation layer and/or a reflective layer is disposed on the side walls of the active layer and the second semiconductor layer.

In the micro LED array chip provided in the embodiment of the present application, in order to protect the light-emitting unit and prevent the side wall leakage of the light-emitting unit, a passivation layer is arranged on the side wall of the active layer and the above-mentioned second semiconductor layer. In order to further prevent the light of the light-emitting unit from being emitted from the side wall to interfere with other light-emitting units, a reflective layer is also arranged on the passivation layer.

Based on the same inventive concept, the present application also provides a display device, comprising: the micro LED array chip as described above in some of the above embodiments; a CMOS backplane, on which a third electrode corresponding to the first electrode and a fourth electrode corresponding to the second electrode are arranged; the micro LED array chip and the CMOS backplane are arranged face to face, and the first electrode and the third electrode are bonded to form an electrical connection, and the second electrode and the fourth electrode are bonded to form an electrical connection.

In the display device provided in the embodiment of the present application, a good conductor layer is arranged on the first semiconductor layer between the light-emitting units of the micro LED array chip bonded to the CMOS backplane, and the good conductor layer is directly connected to the second electrode, so that when the micro LED array chip is driven for display, the light-emitting units in the central area of the LED array chip (or the area far from the second electrode) can directly conduct current to the first semiconductor layer around the light-emitting units in the central area through the second electrode and the good conductor layer, and then pass through the active layer and the second semiconductor layer of the light-emitting units to drive the light-emitting units to emit light; this avoids the problem that in the conventional technology, the light-emitting units in the central area of the micro LED array chip (or the area far from the second electrode) are far from the second electrode, resulting in uneven display due to excessive resistance between the light-emitting units in the central area of the micro LED array chip and the second electrode when current is conducted between the second electrode and the light-emitting units in the central area through the first semiconductor layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of current conduction in a conventional micro LED array chip provided in an embodiment of the present application;

FIG2 is a schematic diagram of a top view structure of a micro LED array chip provided in an embodiment of the present application;

FIG3 is a schematic diagram of current conduction in a micro LED array chip provided in an embodiment of the present application;

FIG4 is a schematic diagram of a top view structure of another micro LED array chip provided in an embodiment of the present application;

FIG5 is a schematic diagram of a top view structure of another micro LED array chip provided in an embodiment of the present application;

FIG. 6 is a schematic diagram of the structure of a display device provided in an embodiment of the present application.

Description of reference numerals:

100-micro LED array chip; 10-first semiconductor layer; 20-second electrode; 30-light-emitting unit; 31-active layer; 32-second semiconductor layer; 33-first electrode; 34-current spreading layer; 35-passivation layer and/or reflection layer; 40-good conductor layer; 50-optical isolation element; 200-CMOS backplane; 60-third electrode; 70-fourth electrode; 80-substrate.

Detailed ways

In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly and comprehensively understood.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

In the embodiments of the present application, a light-emitting unit refers to an independently emitting component in a chip array, and a light-emitting array refers to an array formed by light-emitting units.

In a general LED array chip, the light-emitting units in the LED array chip share an N-type semiconductor layer, and then each light-emitting unit is individually controlled to emit light through a common electrode connected to the N-type semiconductor layer and a driving electrode connected to the P-type semiconductor layer of each light-emitting unit. Referring to FIG1 , in this structure, when the light-emitting units are driven by a common power supply, each light-emitting unit and the common electrode conduct current through a common N-type semiconductor; in this case, the light-emitting units closer to the common electrode and the light-emitting units farther from the common electrode will emit uneven light under the same driving conditions, that is, the light-emitting units closer to the common electrode emit strong light, and the light-emitting units farther from the common electrode emit weak light. This is because the resistance of the N-type semiconductor layer between the light-emitting units farther from the common electrode and the common electrode is larger, which leads to an increase in the overall resistance between the light-emitting units and the common electrode. Therefore, under the same voltage drive, the current will decrease, further resulting in a decrease in the light intensity of the light-emitting units farther from the common electrode.

Based on this, the present application hopes to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in the subsequent embodiments.

Refer to FIG. 2 , which is a schematic structural diagram of a micro LED array chip 100 provided in an embodiment of the present application.

The micro LED array chip 100 includes a substrate 80, and a good conductor layer 40 and a first semiconductor layer 10 stacked in sequence on the substrate 80; a light-emitting array, each light-emitting unit 30 in the light-emitting array includes an active layer 31 and a second semiconductor layer 32 stacked in sequence on the first semiconductor layer 10, and each second semiconductor layer 32 is provided with an independent first electrode 33; a second electrode 20, which is arranged on the good conductor layer 40 and separated from the light-emitting array.

In the embodiment of the present application, the light-emitting unit 30 refers to an independent light-emitting component in the chip array, and the light-emitting array refers to an array formed by the light-emitting units 30. The horizontal transverse cross-section of the light-emitting unit 30 may be circular, square, rectangular or other polygonal; the maximum dimension of the horizontal transverse cross-section of the light-emitting unit 30 is less than 100um, for example, it may be 5um, 8um, 10um, 15um, 18um, 30um, 45um, 60um, 85um, etc.

In the embodiment of the present application, the first semiconductor layer 10 may be an N-doped semiconductor layer, the second semiconductor layer 32 may be a P-doped semiconductor layer, and the active layer 31 may be a multiple quantum well structure (Multiple Quantum Well, MQW). Specifically, the semiconductor layer may be a III-V compound semiconductor material such as GaN, AlGaN, InGaN, AlInP, GaInP, AlGaInP, etc.; the quantum well or quantum layer may be InGaN, AlGaN, InN, InAlN, AlInGaN, etc., and the quantum barrier alternately stacked with the quantum well layer may be GaN, AlN, AlGaN, AlInGaN, InAlN, etc.; the multiple quantum well structure may include one or two or three or four or five or six or seven or eight quantum wells (or at least one quantum hole); the wavelength emitted by the active layer 31 may be a wavelength in the blue light band, a wavelength in the green light band, or a wavelength in the red light band, which is not specifically limited in the embodiment of the present application.

Optionally, the first semiconductor layer 10 may be an N-doped semiconductor layer, and the second semiconductor layer 32 may be a P-doped semiconductor layer.

In the embodiment of the present application, the first electrode 33 is one or more metals that can form an ohmic contact with the second semiconductor layer 32 for current conduction. For example, the first electrode 33 can be formed of a combination of one or more of Cr, Pt, Ti, Ni, Au, and Sn. The second electrode 20 is one or more metals that can form an ohmic contact with the first semiconductor layer 10 for current conduction. For example, the second electrode 20 can be formed of a combination of one or more of Cr, Pt, Ti, Ni, Au, Sn, Ag, Cu, Cu, and Al.

As an optional implementation, the electrical conductivity of the good conductor layer 40 is greater than the electrical conductivity of the first semiconductor layer 10 .

In the micro LED array chip provided in the embodiment of the present application, since the path with the least resistance is selected for current conduction, when the conductivity of the good conductor layer 40 is greater than the conductivity of the first semiconductor layer 10, the current will be preferentially conducted through the good conductor layer 40. Therefore, the resistance of the first semiconductor layer 10 between the second electrode 20 and the light-emitting unit 30 can be effectively reduced, thereby avoiding the phenomenon of uneven light emission of the light-emitting unit 30 array in the micro LED array chip.

As an optional implementation, the good conductor layer 40 includes at least one of Ti and Ni, and has a thickness of 3-50 nm.

As an optional implementation, the good conductor layer 40 includes ITO and Al; wherein the thickness of ITO is 50-200 nm, and the thickness of Al is 1-5 nm.

In the embodiment of the present application, the micro LED array chip emits light from the substrate 80 side. Therefore, in order to ensure the light extraction efficiency, the good conductor layer 40 must have a certain transmittance and a resistivity less than a certain threshold. Therefore, in the embodiment of the present application, the material of the good conductor layer 40 is at least one of Ti and Ni; or a composite layer structure of ITO and Al is used.

Referring to Figure 3, in the micro LED array chip 100 provided in the embodiment of the present application, by setting a good conductor layer 40 between the first semiconductor layer 10 and the substrate 80, and making the good conductor layer 40 directly connected (electrically connected) to the second electrode 20, when the micro LED array chip 100 is driven for display, each light emitting unit 30 in the LED array chip can directly conduct current to the first semiconductor layer 10 around the light emitting unit 30 in the central area through the second electrode 20 and the good conductor layer 40, and then pass through the active layer 31 and the second semiconductor layer 32 of the light emitting unit 30, thereby driving the light emitting unit 30 to emit light; when the conductivity of the good conductor layer 40 is good enough, the influence of the resistance difference of the good conductor layer 40 on the light emitting intensity of each light emitting unit 30 in the LED array chip can be ignored. This can avoid the phenomenon that the light-emitting units 30 in the central area of the micro LED array chip 100 (or the area far away from the second electrode 20) as shown in Figure 3 are far away from the second electrode 20, resulting in uneven display due to excessive resistance between the light-emitting units 30 in the central area of the micro LED array chip 100 and the second electrode 20 when current conduction between the second electrode 20 and the light-emitting units 30 in the central area through the first semiconductor layer.

It is understandable that the current shown in FIG. 3 is only a schematic diagram. In actual applications, since the good conductor layer 40 has good electrical conductivity, each light-emitting unit 30 in the micro LED array chip 100 can obtain current conduction from the point of the good conductor layer 40 that is closest to the light-emitting unit 30 in a straight line, and the influence of the distance between the light-emitting unit 30 and the second electrode 20 can be ignored.

As an optional implementation, the good conductor layer 40 includes at least one of Ti and Ni, and has a thickness of 3-50 nm.

As an optional implementation, the good conductor layer 40 includes ITO and Al; wherein the thickness of ITO is 50-200 nm, and the thickness of Al is 1-5 nm.

In the embodiment of the present application, the micro LED array chip emits light from the substrate 80 side. Therefore, in order to ensure the light extraction efficiency, the good conductor layer 40 must have a certain transmittance and a resistivity less than a certain threshold. Therefore, in the embodiment of the present application, the material of the good conductor layer 40 is at least one of Ti and Ni; or a composite layer structure of ITO and Al is used.

As an optional implementation manner, the first electrode 33 and the end of the second electrode 20 away from the first semiconductor layer 10 are on the same horizontal plane.

In the micro LED array chip 100 provided in the embodiment of the present application, the first electrode 33 and the end of the second electrode 20 away from the first semiconductor layer 10 are on the same horizontal plane, which is conducive to bonding the micro LED array chip 100 to the display backplane.

Referring to FIG. 4 , it is a schematic structural diagram of another micro LED array chip 100 provided in an embodiment of the present application.

In the embodiment of the present application, the micro LED array chip 100 includes a substrate 80 and a good conductor layer 40 and a first semiconductor layer 10 stacked in sequence on the substrate 80; a light-emitting array, each light-emitting unit 30 in the light-emitting array includes an active layer 31 and a second semiconductor layer 32 and a current spreading layer 34 stacked in sequence on the first semiconductor layer 10, and each second semiconductor layer 32 is provided with an independent first electrode 33; a second electrode 20 is provided on the good conductor layer 40 and separated from the light-emitting array; a passivation layer and/or a reflective layer are provided on the side walls of the active layer 31 and the second semiconductor layer 32.

In the embodiment of the present application, the current spreading layer 34 may be ITO; the passivation layer and/or the reflective layer 35 may include a passivation layer or a reflective layer; or may be a combination of a passivation layer and a reflective layer. The passivation layer may be composed of insulating materials such as SiO ₂ and Al ₂ O ₃ ; and the reflective layer may be a distributed Bragg reflector (DBR).

In the embodiment of the present application, other structures of the micro LED array chip 100 are similar to those in the above-mentioned embodiment and will not be described in detail here.

In the micro LED array chip 100 provided in the embodiment of the present application, in order to protect the light-emitting unit 30 and prevent the side wall leakage of the light-emitting unit 30, a passivation layer is arranged on the side wall of the active layer 31 and the above-mentioned second semiconductor layer 32. In order to further prevent the light of the light-emitting unit 30 from being emitted from the side wall to interfere with other light-emitting units 30, a reflective layer is also arranged on the passivation layer.

5 is a schematic structural diagram of another micro LED array chip 100 provided in an embodiment of the present application.

In an embodiment of the present application, a micro LED array chip 100 includes a substrate 80 and a good conductor layer 40 and a first semiconductor layer 10 stacked in sequence on the substrate 80; a light-emitting array, each light-emitting unit in the light-emitting array includes an active layer 31 and a second semiconductor layer 32 and a current spreading layer 34 stacked in sequence on the first semiconductor layer 10, and each second semiconductor layer 32 is provided with an independent first electrode 33; a second electrode 20 is provided on the good conductor layer 40 and separated from the light-emitting array; a passivation layer and/or a reflective layer 35 are provided on the side walls of the active layer 31 and the second semiconductor layer 32; and an optical isolation member 50 is also provided between the light-emitting units 30 of the above-mentioned light-emitting array, and the above-mentioned optical isolation member 50 is used to isolate the light between two adjacent light-emitting units 30.

In the embodiment of the present application, the light isolation element 50 may be a light-absorbing black plastic matrix.

In the embodiment of the present application, other structures of the micro LED array chip 100 are similar to those in the above-mentioned embodiment and will not be described in detail here.

In the micro LED array chip 100 provided in the embodiment of the present application, light isolators 50 are provided between the light emitting units 30 of the light emitting array to effectively prevent light from crosstalking between the light emitting units 30 .

Referring to Figure 6, a display device provided by the present application includes: the micro LED array chip 100 as described above in some of the above embodiments; a CMOS backplane 200, on which a third electrode 60 corresponding to the first electrode 33 and a fourth electrode 70 corresponding to the second electrode 20 are arranged; the micro LED array chip 100 and the CMOS backplane 200 are arranged face to face, and the first electrode 33 and the third electrode 60 are bonded to form an electrical connection, and the second electrode 20 and the fourth electrode 70 are bonded to form an electrical connection.

In the display device provided in the embodiment of the present application, a good conductor layer 40 is provided on the first semiconductor layer 10 between the light-emitting units of the micro LED array chip bonded to the CMOS backplane, and the good conductor layer 40 is directly connected to the second electrode 20, so that when the micro LED array chip is driven for display, the light-emitting units 30 in the central area of the LED array chip (or the area far from the second electrode 20) can directly conduct current to the first semiconductor layer 10 around the light-emitting units 30 in the central area through the second electrode 20 and the good conductor layer 40, and then pass through the active layer 31 and the second semiconductor layer 32 of the light-emitting units 30, thereby driving the light-emitting units 30 to emit light; this avoids the problem that in the conventional technology, the light-emitting units in the central area of the micro LED array chip (or the area far from the second electrode 20) are far from the second electrode, resulting in uneven display due to excessive resistance between the light-emitting units in the central area of the micro LED array chip and the second electrode when current is conducted between the second electrode and the light-emitting units in the central area through the first semiconductor layer.

It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made according to the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims (10)

1. A micro LED array chip, comprising:

A substrate;

a good conductor layer and a first semiconductor layer stacked in this order on the substrate;

A light emitting array, each light emitting unit in the light emitting array comprising an active layer and a second semiconductor layer sequentially stacked on the first semiconductor layer, and each second semiconductor layer being provided with an independent first electrode;

and a second electrode disposed on the good conductor layer and spaced apart from the light emitting array.

2. The micro LED array chip of claim 1, wherein the good conductor layer has a conductivity greater than a conductivity of the first semiconductor layer.

3. The micro LED array chip of claim 2, wherein the good conductor layer comprises at least one of Ti and Ni, and has a thickness of 3-50nm.

4. The micro LED array chip of claim 2, wherein the good conductor layer comprises ITO and Al; wherein the thickness of ITO is 50-200 nm, and the thickness of Al is 1-5 nm.

5. The micro LED array chip of claim 1, wherein the second electrode is disposed on the good conductor layer along a periphery of the light emitting array.

6. The micro LED array chip of claim 1, wherein an end of the first electrode and the second electrode remote from the first semiconductor layer are on the same horizontal plane.

7. The micro LED array chip of any one of claims 1-6, wherein the good conductor layer has a transmittance of 65% to 95%.

8. The micro LED array chip of any one of claims 1 to 6, wherein a light separator for separating light between adjacent two light emitting units is further provided between the light emitting units of the light emitting array.

9. The micro LED array chip according to any one of claims 1 to 6, wherein a passivation layer and/or a reflective layer is provided on sidewalls of the active layer and the second semiconductor layer.

10. A display device, comprising:

the micro LED array chip of any one of claims 1-9;

A CMOS back plate on which a third electrode corresponding to the first electrode and a fourth electrode corresponding to the second electrode are disposed;

the micro LED array chip and the CMOS backboard are arranged face to face, the first electrode and the third electrode are bonded to form electric connection, and the second electrode and the fourth electrode are bonded to form electric connection.