WO2022127457A1

WO2022127457A1 - Led device for visible light communication

Info

Publication number: WO2022127457A1
Application number: PCT/CN2021/130180
Authority: WO
Inventors: 李国强
Original assignee: 河源市众拓光电科技有限公司
Priority date: 2020-12-18
Filing date: 2021-11-12
Publication date: 2022-06-23
Also published as: CN112635512B; CN112635512A

Abstract

Disclosed is an LED device for visible light communication. A plurality of microarray and individually addressable LED chips are integrated; the plurality of LED chips are divided into LED chip areas of different light colors; and chips in different areas alternate between light and dark to achieve signal recognition. The LED device is composed of chips in four parts: R, G and B areas and a white-light area. The R, G and B areas have red, green and blue N*N microarray LED array chips respectively. A single chip is limited to 100-200 um in size, and has excellent modulation characteristics. The white-light area has a high-power RGB white-light LED chip. By using on-off key control and the technology of pulse width modulation, microarray LEDs in different areas alternate between light and dark to couple different types of light, and the light is recognized through a photoelectric detector at a receiving end and can be used for realizing a high-speed and stable visible light system. The present invention has a high modulation bandwidth, and can realize the functions of communication and illumination at the same time.

Description

A visible light communication LED device

technical field

The invention relates to the technical field of visible light communication, in particular to a visible light communication LED device.

Background technique

As a new type of green solid-state light source, compared with traditional incandescent lamps and energy-saving lamps, LED has excellent characteristics such as low power consumption and long life, and has strong competitiveness in the field of lighting. Its influence has also penetrated into the global economy, Various fields of science and technology have brought earth-shaking changes to human life.

The popularity of solid-state lighting has promoted the development of visible light communication. Using the characteristics of fast response and easy modulation of LEDs, LEDs for both communication and lighting have broad application prospects. Compared with traditional radio communication, visible light communication uses light as the transmission medium, which has good security, strong anti-electromagnetic interference, high communication rate, rich spectrum resources, and white light and radio frequency signals do not interfere with each other, and can coexist with wireless communication networks. compatible.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a visible light communication LED device with high modulation bandwidth and satisfying communication and lighting functions at the same time.

The present invention realizes above-mentioned purpose through following technical means:

A visible light communication LED device, by integrating a plurality of individually addressable microarray LED chips, the plurality of LED chips are divided into LED chip regions of different light colors, and the light and dark of the chips in different regions are alternated to realize signal identification.

Preferably, the visible light communication LED device includes four different LED chip areas, which are the red microarray LED R area, the green microarray LED G area, the blue microarray LED B area and the white light LED RGB area.

Preferably, the chip selected for the R region is an N×N matrix addressing array of micro-array LEDs, the p-electrodes of 2N micro-LED units in every two rows are connected to each other, and all the micro-LED units share n-electrodes.

Preferably, the chips selected for the R, G, and B regions are micro-array LEDs with an N×N matrix addressing array. The n electrodes of 2N micro LED units in every two rows are connected to each other, and the p electrodes of the micro LED units in every two columns are connected. Electrodes are interconnected.

Preferably, in the R, G and B regions, the diameter of a single light-emitting unit of the micro LED is 100-200um, the distance between adjacent micro LED units is 50um, and the side length of the rectangular pad metal layer is 50um.

Preferably, GaN material is selected for the blue light B region and the green light G region, and the LED structure is grown on the sapphire substrate by using MOCVD technology. , InGaN/GaN multiple quantum well layer, AlGaN current blocking layer and p-GaN layer; by adjusting the thickness of InGaN/GaN multiple quantum well to meet the requirements of different wavelengths of light emission in G and B regions;

Using the photolithography process and the inductively coupled plasma etching process, the micro LED devices in the array are electrically isolated from each other, and the p-GaN layer, the AlGaN current blocking layer and the InGaN/GaN multiple quantum well layer are removed in the selected part of the etching. Until the n-GaN layer is exposed; the diameter of the outer n-GaN layer region is 100um, and the diameter of the inner p-GaN layer region is 50um;

The two annular regions were again exposed by photolithography, Cr/Pd/Au metal stacks were deposited by e-beam evaporation as p-type and n-type electrodes, and rapidly annealed in a N atmosphere at 200 °C for ₂ min. The inner diameter difference of the n electrodes is all 5um.

Preferably, the R, G and B regions meet the requirements of different wavelengths of emitted light, wherein the wavelength of the red light in the R region is 600-620 nm, the wavelength of the green light in the G region is 520-540 nm, and the wavelength of the blue light in the B region is 440-460 nm .

Preferably, the white light area is a high-power RGB type white light LED chip to meet daily lighting requirements.

Preferably, using the MIMO technology, the micro-array LED chips in different areas of the R, G, and B area arrays can be controlled separately to transmit different data and be received by multiple photodetectors.

Preferably, using on-off key control and pulse width modulation technology, different signals are amplified by the driver and then loaded on the chips in the three regions of R, G, and B through the DC biaser, and the three beams of different colors are Coupling in space and transmission in space; at the receiving end, red, green and blue filters are used to select signals of different wavelengths, and then the receiving circuit performs signal acquisition and back-end processing to realize signal identification and data transmission .

Compared with the prior art, the beneficial effects of the present invention at least include:

1. The microarray LEDs in the R, G, and B areas have a large modulation bandwidth and can realize high-speed data transmission;

2. The use of red, green and blue wavelength division multiplexing technology can improve the transmission capacity of the visible light communication system;

3. Large-size LEDs in the white light area can be prepared as high-efficiency devices, which are suitable for the field of LED lighting.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

FIG. 1 is a top-view structural schematic diagram of a microarray LED integrated chip according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a microarray LED in regions R, G, and B according to an embodiment of the present invention;

3 is a schematic top-view structural diagram of a microarray LED chip in the R region according to an embodiment of the present invention;

4 is a schematic cross-sectional view of a microarray LED chip in regions G and B according to an embodiment of the present invention;

5 is a schematic top-view structural diagram of a single microarray LED chip in areas G and B according to an embodiment of the present invention;

6 is a top-view structural schematic diagram of the interconnection of row electrodes of microarray LED chips in regions G and B of the embodiment of the present invention;

FIG. 7 is a schematic top-view structural diagram of the interconnection of column electrodes of microarray LED chips in regions G and B of the embodiment of the present invention;

8 is a schematic cross-sectional view of the interconnection of column electrodes of microarray LED chips in regions G and B of the embodiment of the present invention.

Detailed ways

In order to make the above objects, features and advantages of the present invention more clearly understood, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be pointed out that the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, those of ordinary skill in the art can obtain all the Other embodiments fall within the protection scope of the present invention.

Example

As shown in FIG. 1 and FIG. 2 , by integrating a plurality of individually addressable LED chips by microarrays, they are the red light R area 1, the green light G area 2, the blue light B area 3 and the white light RGB area 4. The chips selected for R, G, and B areas are micro-array LEDs of 8×8 matrix addressing arrays, and the white light areas are high-power RGB white light LED chips.

As shown in Fig. 2 and Fig. 3, a typical AlGaInP red light LED chip is selected for the red light R region, wherein the wavelength of the red light in the R region is 600-620 nm. The photolithography process and the inductively coupled plasma etching process are used to electrically isolate the micro-LED devices in the array from each other to form an 8×8 micro-array LED array with a size of 100um. A pad metal layer is deposited in the rectangular area surrounded by 2×2 micro-LED units, and interconnected with the p-electrodes of the surrounding 4 micro-LED units. 16 micro-LED units can be controlled together, and the row of pad contacts is used to connect the positive pole of the power supply. All the microarray LEDs in the array share the n-pole, and an n-pad contact layer is drawn out on the bottom of the chip to connect the negative pole of the power supply.

As shown in Figure 4 and Figure 5, the blue light B area and the green light G area are made of GaN material, and the LED structure is grown on the sapphire substrate using MOCVD technology. From bottom to top, the sapphire substrate 5 and the undoped GaN buffer are respectively Layer 6 , n-GaN layer 7 , InGaN/GaN multiple quantum well layer 8 , AlGaN current blocking layer 9 , p-GaN layer 10 . By adjusting the thickness of the InGaN/GaN multiple quantum wells to meet the requirements of different wavelengths of light emitted in the G and B regions, the wavelength of the green light in the G region is 520-540 nm, and the wavelength of the blue light in the B region is 440-460 nm.

Using the photolithography process and the inductively coupled plasma etching process, the micro LED devices in the array are electrically isolated from each other, and the p-GaN layer, the AlGaN current blocking layer and the InGaN/GaN multiple quantum well layer are removed in the selected part of the etching. until the n-GaN layer is exposed. The diameter of the outer n-GaN layer region is 100um and the diameter of the inner p-GaN layer region is 50um.

The two annular regions shown in Figure 5 were again exposed by photolithography, Cr/Pd/Au metal stacks were deposited by e-beam evaporation as p-type electrode 12 and n-type electrode 11, and were deposited at ₂₀₀ °C in a N atmosphere After rapid annealing for 2 minutes, the inner diameter difference between the annular p-electrode 12 and the annular n-electrode 11 is both 5um.

As shown in Fig. 6, Fig. 7, Fig. 8, a pad metal layer is deposited on the rectangular area surrounded by 2×2 micro-LED units, and interconnected with the n-electrodes of the surrounding 4 micro-LED units through n-type metal wires. A row pad contact layer is drawn out, so that 16 micro-LED units in every two rows can be controlled together, and the row pad contact layer is used to connect the negative pole of the power supply.

After depositing a passivation layer in a selected area in the column direction, the p-electrodes of 8 micro-LED monoliths in each column are electrode-interconnected, and a column pad contact layer is jointly drawn out for every two columns, so that the 16 micro-LED units are connected to each other. It can be controlled together, and the pad contact layer of this column is used to connect the positive pole of the power supply.

The four types of microarray LED chips are arranged in a certain structure and integrated on the substrate, not limited to four cores.

The invention utilizes the on-off key control technology and the pulse width modulation technology to control the micro-array LEDs with different light colors in different areas, so as to couple out different lights for signal identification and data transmission.

The visible light communication LED device of the present invention uses on-off key control technology and pulse width modulation technology to control the luminous conditions of microarray LEDs with different light colors in different regions, so that they can couple out different lights, and can realize high-speed data transmission through optical signals. Compared with LED chips, the device has better modulation bandwidth, larger information transmission capacity, and can meet lighting needs at the same time.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the patent of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

A visible light communication LED device is characterized in that, by integrating a plurality of individually addressable LED chips in a microarray, the plurality of LED chips are divided into LED chip areas of different light colors, and the chips in different areas are alternated between light and dark. Implement signal recognition.
The visible light communication LED device according to claim 1, wherein the visible light communication LED device comprises four different LED chip regions, which are respectively a red light microarray LED R region, a green light microarray LED G region, and a blue light microarray LED region. Microarray LED B area and white LED RGB area.
The visible light communication LED device according to claim 2, wherein the chips of the R-region micro-array LED are all N×N array structures, and the p-electrodes of the 2×2 micro-LED units are interconnected with the pad metal layer electrodes surrounded by them. , every two rows of 2N micro-LED units lead out a p pad contact layer through p-type metal wires; all the micro-array LEDs in the array share n-pole, and lead out an n pad contact layer on the bottom surface of the chip.
The visible light communication LED device according to claim 2, wherein the chips of the micro-array LEDs in the G and B regions are all of an N×N array structure, and the n-electrode of the 2×2 micro-LED unit and the pad metal layer surrounded by it Electrode interconnection, 2N micro-LED units in every two rows lead out a row pad contact layer through n-type metal wires; 2N micro-LED monolithic p-electrodes in every two columns are electrode interconnected, and lead out a column pad contact layer together.
The visible light communication LED device according to claim 2, wherein in the R, G, and B regions, the diameter of a single light-emitting unit of the micro-LED is 100-200um, and the distance between adjacent micro-LED units is 50um, wherein the rectangular pad The side length of the metal layer is 50um.
The visible light communication LED device according to claim 2, wherein the blue light B area and the green light G area are made of GaN material, and the LED structure is grown on the sapphire substrate by using MOCVD technology, and the sapphire substrate, Undoped GaN buffer layer, n-GaN layer, InGaN/GaN multi-quantum well layer, AlGaN current blocking layer and p-GaN layer; By adjusting the thickness of InGaN/GaN multi-quantum well to meet different wavelength emission in G and B regions light requirements;

Using the photolithography process and the inductively coupled plasma etching process, the micro LED devices in the array are electrically isolated from each other, and the p-GaN layer, the AlGaN current blocking layer and the InGaN/GaN multiple quantum well layer are removed in the selected part of the etching. Until the n-GaN layer is exposed; the diameter of the outer n-GaN layer region is 100um, and the diameter of the inner p-GaN layer region is 50um;

The two annular regions were again exposed by photolithography, Cr/Pd/Au metal stacks were deposited by e-beam evaporation as p-type and n-type electrodes, and rapidly annealed in a N atmosphere at 200 °C for 2 min. The inner diameter difference of the n electrodes is all 5um.
The visible light communication LED device according to claim 2, wherein the R, G and B regions meet the requirements of different wavelengths of emitted light, wherein the wavelength of the red light in the R region is 600-620 nm, and the wavelength of the green light in the G region is 520 nm. ~540nm, the wavelength of blue light in the B region is 440 ~ 460nm.
The visible light communication LED device according to claim 2, wherein the high-power RGB white light LED chip in the white light region emits stable white light under the action of the DC power supply.
The visible light communication LED device according to claim 2, characterized in that, using MIMO technology, the micro-array LED chips in different areas of the R, G, and B area arrays can be controlled separately, send different data, and are detected by a plurality of photodetectors. take over.
The visible light communication LED device according to claim 2, characterized in that, by using on-off key control and pulse width modulation technology, different signals are amplified by a driver and then loaded into three of R, G, and B through a DC biaser. On the chip in the area, the three beams of different colors are coupled in space and transmitted in space; at the receiving end, red, green, and blue filters are used to select signals of different wavelengths, and then the receiving circuit performs the signal processing. Acquisition and back-end processing to realize signal identification and data transmission.