Light emission control method and light emission control device

Abstract

The present invention discloses a light output control method and a light output control device. The light output control method includes the steps of: coating a high refractive index material on a low refractive index material layer of a high-voltage LED chip to obtain a high refractive index material layer; forming a reflective enhanced film system through the high refractive index material layer and the low refractive index material layer, so that the reflective enhanced film system reflects the received light to the outside of the high-voltage LED chip. The present invention improves the external quantum light output efficiency of the high-voltage LED chip.

Description

Technical Field

[0001] The present invention relates to the technical field of LEDs, and particularly to a light output control method and a light output control device. Background Art

[0002] In the display fields such as mobile phones, televisions, and laptops, with the improvement of the requirements for image quality, the multi-zone fine light control technology with high peak brightness of HDR (High Dynamic Range Imaging) is popular in the market. The multi-zone fine light control technology is to separately control the light emission of each single-cell LED chip in a high-voltage LED (light-emitting diode) chip. Since the single-cell LED chip has a pentahedron structure and emits light from five sides, that is, light is emitted from the top surface and four side surfaces. However, between adjacent single-cell LED chips, the light emitted from adjacent side surfaces will be absorbed by each other, resulting in the inability to emit light from the four side light-emitting surfaces, reducing the light extraction rate of the high-voltage LED chip and weakening its light-emitting ability. The above light coupling and propagation problems will occur on the four side wall light-emitting surfaces between each single-cell LED chip of the high-voltage LED chip. The overall light output efficiency of the high-voltage LED chip will be greatly reduced, resulting in the loss of photoelectric conversion efficiency, that is, the external quantum light output efficiency of the high-voltage LED chip is low. Summary of the Invention

[0003] The main object of the present invention is to provide a light output control method and a light output control device, aiming to solve the problem of low external quantum light output efficiency of high-voltage LED chips.

[0004] To achieve the above object, the present invention provides a light output control method, and the light output control method includes the steps of:

[0005] Coating a high refractive index material on the low refractive index material layer of a high-voltage LED chip to obtain a high refractive index material layer;

[0006] Forming a reflective enhancement film system through the high refractive index material layer and the low refractive index material layer, so that the reflective enhancement film system reflects the received light to the outside of the high-voltage LED chip.

[0007] Optionally, the step of coating a high refractive index material on the low refractive index material layer of a high-voltage LED chip to obtain a high refractive index material layer includes:

[0008] Coating a high refractive index material on the low refractive index material layer on the side surface of a single-cell chip in a high-voltage LED chip to obtain a high refractive index material layer located on the low refractive index material layer, where the number of the single-cell chips is multiple.

[0009] Optionally, the step of coating a high refractive index material on a low refractive index material layer on the side surface of a single cell chip in a high-voltage LED chip to obtain a high refractive index material layer on the low refractive index material layer includes:

[0010] Obtain a first parameter of the low refractive index material layer, and obtain a thickness to be coated of the high refractive index material layer according to the first parameter, a preset second parameter of the high refractive index material, and the peak wavelength of the high-voltage LED chip;

[0011] Coat the high refractive index material on the side surface of the single cell chip in the high-voltage LED chip according to the thickness to be coated to form a high refractive index material layer.

[0012] Optionally, the first parameter includes a first refractive index and a first film thickness of the low refractive index material layer; the preset second parameter includes a second refractive index of the high refractive index material;

[0013] The step of obtaining the thickness to be coated of the high refractive index material layer according to the first parameter, the preset second parameter of the high refractive index material, and the peak wavelength of the high-voltage LED chip includes:

[0014] Obtain the thickness to be coated of the high refractive index material layer according to the first refractive index, the first film thickness, the second refractive index, and the peak wavelength of the high-voltage LED chip.

[0015] Optionally, before the step of coating a high refractive index material on the low refractive index material layer of the high-voltage LED chip to obtain a high refractive index material layer, further includes:

[0016] Epitaxially grow a Gan buffer layer, an N-GaN layer, an MQW quantum well layer, a P-GaN layer, and an ITO layer on a sapphire substrate in sequence;

[0017] Etch the Gan buffer layer, the N-GaN layer, the MQW quantum well layer, the P-GaN layer, and the ITO layer with a mixed gas of CL2 / BCL3 to obtain the epitaxial layers of all the single cell chips;

[0018] Coat a low refractive index material on the sapphire substrate and the epitaxial layer to form a low refractive index material layer, and obtain the high-voltage LED chip.

[0019] Optionally, the step of etching the Gan buffer layer, the N-GaN layer, the MQW quantum well layer, the P-GaN layer, and the ITO layer with a mixed gas of CL2 / BCL3 includes:

[0020] Etch the Gan buffer layer, N-GaN layer, MQW quantum well layer, P-GaN layer, and ITO layer with a mixed gas of CL2 / BCL3 toward the chip substrate direction, and expose part of the N-GaN layer;

[0021] Epitaxially grow electrode layers on the ITO layer and the P-GaN layer respectively to obtain the epitaxial layer of the unit cell chip.

[0022] Optionally, the high-voltage LED chip includes a plurality of unit cell chips, and the unit cell chip includes an epitaxial layer and a low-refractive-index material layer disposed on the epitaxial layer.

[0023] Optionally, the unit cell chip further includes a sapphire substrate, and the epitaxial layer includes a Gan buffer layer, an N-GaN layer, an MQW quantum well layer, a P-GaN layer, an ITO layer, and an electrode layer. Among them, the Gan buffer layer, the N-GaN layer, the MQW quantum well layer, the P-GaN layer, and the ITO layer are epitaxially grown on the sapphire substrate in sequence, and the electrode layers are respectively disposed on the ITO layer and the N-GaN layer.

[0024] Optionally, the electrode layer includes an N electrode and a P electrode, and the N electrode in one of the two arbitrarily adjacent unit cell LED chips is connected to the P electrode in the other unit cell LED chip.

[0025] Optionally, the low-refractive-index material is SIO2, and the high-refractive-index material is TiO2.

[0026] In addition, to achieve the above object, the present invention further provides a light output control device. The light output control device is applied to the above light output control method. The light output control device includes a high-voltage LED chip and a high-refractive-index material layer coated on the high-voltage LED chip. Among them, the high-refractive-index material layer and the low-refractive-index material layer in the high-voltage LED chip form a reflective enhancement film system.

[0027] The present invention provides a light output control method. By coating a high-refractive-index material on the low-refractive-index material layer of a high-voltage LED chip, a high-refractive-index material layer is obtained; and through the high-refractive-index material layer and the low-refractive-index material layer, a reflective enhancement film system is formed, so that the reflective enhancement film system reflects the received light to the outside of the high-voltage LED chip, avoiding the situation that the light emitted by the high-voltage LED chip is absorbed. The light can be reflected to the outside of the high-voltage LED chip through the emission enhancement film system jointly formed by the high-refractive-index material layer and the low-refractive-index material layer, improving the external quantum light output efficiency of the high-voltage LED chip, thereby enhancing the brightness of the high-voltage LED chip and enhancing the HDR effect of the application end. Description of the Drawings

[0028] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments in accordance with the present invention, and are used together with the specification to explain the principles of the present invention.

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings required for use in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a working principle diagram of the DBR mirror;

[0031] Figure 2 It is a schematic structural diagram of the high-voltage LED chip of the present invention;

[0032] Figure 3 It is a schematic circuit principle diagram of the high-voltage LED chip of the present invention;

[0033] Figure 4 It is a schematic diagram of the variation relationship between the quantum efficiency of a single LED and the forward input current;

[0034] Figure 5 It is a schematic diagram of light propagation between adjacent unit cells of the high-voltage chip;

[0035] Figure 6 It is a schematic diagram of light propagation after coating a high refractive index material on the high-voltage LED chip;

[0036] Figure 7 It is a schematic structural diagram of the light output control device;

[0037] Figure 8 It is a schematic flowchart of an embodiment of the light output control method of the present invention;

[0038] Figure 9 It is a schematic flowchart of another embodiment of the light output control method of the present invention.

[0039] The realization of the objectives, functional features, and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0040] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0041] For the convenience of those skilled in the art to understand the present invention and to ensure the feasibility of the present invention, the Bragg reflection enhancement theory related to the DBR (distributed Bragg reflection) in the present invention is described herein.

[0042] It can be known from the Bragg reflection theory that when light passes through different media, reflection occurs at the interface, and the magnitude of the reflectivity is related to the refractive index between the media. By alternately stacking thin films with different refractive indices periodically, when light passes through these thin films with different refractive indices, since the light reflected from each layer undergoes constructive interference due to the change in the phase angle, and then combines with each other, strong reflected light is obtained.

[0043] The working principle of the DBR mirror is as Figure 1 shown. According to the reflection principle, when light travels from an optically thinner medium n1 to an optically denser medium n2 (refractive index n2 > n1), the reflected light undergoes a half-wave loss at the interface, and the phase changes by π. When light enters the DBR layer, reflections occur at the upper and lower surfaces of each layer. According to the design principle of the DBR, when the working center wavelength of the DBR is λ0 and the thickness is d [d = λ0 / (4n)], the optical path difference between the two reflections is 0.5λ. This optical path difference corresponds to a phase change of π, and a half-wave loss also causes a phase change of π. Finally, the two reflected lights are in phase and superimposed to enhance, that is, the overall reflection coefficient is increased. In fact, the DBR is an alternating stack of two media with different refractive indices. The more layers the DBR has, the higher the reflectivity, and finally the reflection coefficient of the DBR can reach a very high level.

[0044] Combined with the following solution of the present invention, the present invention utilizes the principle of reflection enhancement of the Bragg mirror, using a periodic structure composed of two materials with different refractive indices arranged alternately in the ABAB manner, and the optical thickness of each layer of material is 1 / 4 of the central reflection wavelength. Therefore, it is a quarter-wavelength multi-layer system, equivalent to a simple set of photonic crystals. Since electromagnetic waves with frequencies falling within the bandgap range cannot penetrate, the reflectivity of the Bragg mirror can reach more than 95%. That is, it can reflect the light on the side surface of each single-cell chip in the high-voltage chip, thereby improving the external quantum light extraction efficiency of the high-voltage LED chip and achieving a high-brightness effect.

[0045] An embodiment of the present invention provides a high-voltage LED chip. Refer to Figure 2 , the high-voltage LED chip includes a plurality of single-cell chips 10, and each single-cell chip 10 includes an epitaxial layer and a low-refractive-index material layer 8 disposed on the epitaxial layer. Among them, the single-cell chip 10 includes five light-emitting surfaces, namely the top surface and four side surfaces, and the single-cell chips 10 are arranged in sequence on the high-voltage LED chip, so that one side surface of the four side surfaces of the single-cell chip 10 is opposite to one side surface of other single-cell chips 10, and the light emitted from the side surface can irradiate the side surfaces of other single-cell chips 10. The epitaxial layer is used to realize the light emission of the LED chip and change the color of the light, etc.; the low-refractive-index material layer 8 is SiO2 and is used to isolate each single-cell chip 10 in the high-voltage LED chip.

[0046] Furthermore, the single-cell chip 10 further includes a sapphire substrate. The epitaxial layer includes a Gan buffer layer 2, an N-GaN layer 3, an MQW quantum well layer 4, a P-GaN layer 5, an ITO layer 6, and an electrode layer. Among them, the Gan buffer layer 2, the N-GaN layer 3, the MQW quantum well layer 4, the P-GaN layer 5, and the ITO layer 6 are epitaxially grown on the sapphire substrate in sequence, and the electrode layer is disposed on the ITO layer 6 and the N-GaN layer 3 respectively. Among them, epitaxial growth is a chemical process, that is, a single-crystal layer (including the Gan buffer layer 2, the N-GaN layer 3, the MQW quantum well layer 4, the P-GaN layer 5, the ITO layer 6, and the electrode layer) with certain requirements and the same crystal orientation as the substrate is grown on a single-crystal substrate (sapphire substrate), just like the original sapphire substrate extends outward for a section, which can greatly improve the design flexibility of the high-voltage LED chip and the performance of the high-voltage LED chip, and at the same time meet the requirements for the light emission of the high-voltage LED chip.

[0047] Furthermore, the electrode layer includes an N electrode 72 and a P electrode 71, and the N electrode 72 in one of any two adjacent single-cell chips 10 is connected to the P electrode 71 in the other single-cell chip 10. Among them, the P electrode and the N electrode are connected by a conductive metal 73. The P electrode 71 passes through the low-refractive-index material layer 8 and is disposed on the ITO layer 6 and is connected to the P-GaN layer 5. The N electrode 72 passes through the low-refractive-index material layer 8 and is disposed on the N-GaN layer 3. At the same time, the N electrodes 72 and the P electrodes 71 in two different single-cell chips 10 are connected to each other, so that all the single-cell chips 10 in the high-voltage LED chip are connected in series. Refer to Figure 3 , Figure 3Schematic diagram of the circuit principle of a high-voltage LED chip. By connecting all the single-cell chips 10 in series to form a monolithic integrated high-voltage LED chip, the drive current of each single-cell chip 10 can be effectively reduced, that is, a small-current method can be used to drive the high-voltage chip, and the problem of difficult voltage reduction can be solved.

[0048] It should be noted that in the display fields such as mobile phones, TVs, and laptops, with the improvement of the requirement for image quality, the HDR peak high brightness and the multi-zone fine dimming technology are welcomed by the market. In terms of the HDR high-brightness requirement, the requirement for the LED brightness is increased, that is, the LED input current needs to be increased. Figure 4 Shows the relationship between the quantum efficiency of a single LED and the forward input current. Among them, the abscissa is the forward input current, and the ordinate is the quantum efficiency of a single LED. The waveform diagrams from top to bottom are the variation relationships between the quantum efficiency and the forward input current of different LEDs. It can be seen that under small-current drive, as the current increases, the quantum efficiency rises rapidly and reaches a peak. After that, as the current increases, the quantum efficiency shows a rapid downward trend. In summary, when a large current is used to drive the LED chip, the luminous efficiency drops severely and the optoelectronic conversion efficiency is low. On the other hand, since alternating current requires a transformer and a power supply voltage reduction to drive a high-power chip, for the current multi-lamp and multi-zone requirements of HDR technology, taking a 4-lamp one-zone example with a conventional LED chip, the single-lamp voltage is 3V and one zone is 12V, that is, 220V needs to be reduced to 12V through power conversion and other voltage reduction design methods. During the voltage reduction process of the circuit, a lot of heat will be lost and the power switch is prone to failure and damage. At the same time, the multi-lamp and multi-zone scheme will cause the main circuit current to be too large. Taking 200mA per zone and 200 zones as an example, the main circuit needs 4A, which is easy to cause excessive heat and damage to the circuit.

[0049] To solve the above problems, by connecting each single-cell chip 10 in the high-voltage LED chip of the present invention in series, the LED performance can be improved by a high-voltage and low-current drive method, thereby avoiding the problem that the circuit is easily damaged due to excessive heat.

[0050] Furthermore, based on the hardware structure of the above high-voltage LED chip, since the single-cell chip 10 in the high-voltage LED chip is a pentahedron structure and emits light in a five-sided form, that is, light is emitted from the top surface and the four side surfaces. Refer to Figure 5 , Figure 5It is a schematic diagram of light propagation between adjacent unit cells of a high-voltage chip. Since the chip emits light from five sides, that is, light is emitted from the top surface and four side surfaces. Point A in the figure is an arbitrary point on a side wall light-emitting surface of the unit cell chip 101. The light emitted from point A has a random direction and covers the entire outer surface of the LED. Within the entire range of AB and AC, the light between AE and AD will propagate to the surface of chip 2. Since the outermost layer of the surface of the unit cell chip 102 is a PV layer (photovoltaic) with a material of SIO2, the DE surface will absorb the incident light within the angle θ between AE and AD, that is, this part of the light will be absorbed between the unit cells of the chip 10 and cannot emit light from the light-emitting surface, reducing the light extraction efficiency of the chip and weakening its light-emitting ability. The above-mentioned light coupling and propagation problems will occur on the four side wall light-emitting surfaces between each unit cell of the high-voltage chip. As a result, the light extraction efficiency of the overall high-voltage chip will be greatly reduced, causing losses in the photoelectric conversion efficiency and a relatively low overall brightness.

[0051] Further, please refer to Figure 7 and Figure 6 , Figure 6 which is a schematic diagram of light propagation after coating a high-refractive-index material on a high-voltage LED chip. Figure 7 Figure is a schematic structural diagram of a light extraction control device, and the light extraction control device includes a high-voltage LED chip and a high-refractive-index material layer 9 coated on the high-voltage LED chip.

[0052] In the present invention, by coating a layer of high-refractive-index material on the outermost low-refractive-index material layer of the high-voltage LED chip, the high-refractive-index material layer and the low-refractive-index material layer jointly form an emission-enhanced film system, and the light emitted from the side of each unit cell chip in the high-voltage LED chip will be emitted outside the high-voltage LED chip, solving the problem of light absorption, significantly improving the light-emitting efficiency of the high-voltage LED chip, and increasing the brightness of the high-voltage LED chip.

[0053] Specifically, an embodiment of the present invention provides a light extraction control method. In an embodiment of the light extraction control method of the present invention, referring to Figure 8 , the light extraction control method includes:

[0054] Step S10, coating a high-refractive-index material on the low-refractive-index material layer of the high-voltage LED chip to obtain a high-refractive-index material layer;

[0055] In an embodiment, step S10 further includes:

[0056] Step A11, coating a high-refractive-index material on the low-refractive-index material layer on the side of the unit cell chip in the high-voltage LED chip to obtain a high-refractive-index material layer located on the low-refractive-index material layer, where the number of the unit cell chips is multiple.

[0057] Specifically, since a high-voltage LED chip contains multiple single-cell chips arranged in sequence, and the high-voltage LED chip emits light through multiple single-cell chips, and the single-cell chip emits light in a five-sided manner, that is, the top surface and four side surfaces emit light. When the side surfaces emit light, the emitted light is easily absorbed by the side surfaces of adjacent single-cell chips, resulting in low brightness of the high-voltage LED chip. Therefore, it is only necessary to coat high-refractive-index materials on the four side surfaces of each single-cell chip, so that a reflective enhancement film system formed by the low-refractive-index material layer and the high-refractive-index material layer can refract the light emitted by other single-cell chips received by the single-cell chip to the outside of the high-voltage LED chip, avoiding the situation where the side surfaces of the single-cell chip absorb light and cause low brightness of the high-voltage LED chip. Among them, the low-refractive-index material layer is the outermost SIO2 of the high-voltage LED chip. It is only necessary to match the high-refractive-index material layer on the original SIO2 layer to form a reflective enhancement film system.

[0058] Step S20, form a reflective enhancement film system through the high-refractive-index material layer and the low-refractive-index material layer, so that the reflective enhancement film system reflects the received light to the outside of the high-voltage LED chip.

[0059] The reflective enhancement film system includes the outermost SIO2 layer of the high-voltage LED chip and the high-refractive-index material layer coated on the SIO2 layer. Among them, the low-refractive-index material layer can be TiO2. In addition, it should be noted that the side wall of the DBR-coated high-voltage chip shown in the present invention is one of the structures to solve the problem of low brightness caused by light coupling and absorption between adjacent single cells, and the reflectivity is about 95%. If a higher reflectivity is required, for example, if the reflectivity needs to be increased to 99%, the number of pairs of the reflective enhancement film system can be increased, such as two pairs or three pairs of the reflective enhancement film system. The present invention does not limit this. According to the above DBR reflection principle, the more pairs of the reflective enhancement film system, the stronger the reflection ability. That is, those skilled in the art can reasonably design and develop the coating system according to actual needs and cost considerations to improve the light extraction efficiency and brightness.

[0060] The present invention provides a light extraction control method. By coating a high-refractive-index material on the low-refractive-index material layer of the high-voltage LED chip, a high-refractive-index material layer is obtained; and a reflective enhancement film system is formed through the high-refractive-index material layer and the low-refractive-index material layer, so that the reflective enhancement film system reflects the received light to the outside of the high-voltage LED chip, avoiding the situation where the light emitted by the high-voltage LED chip is absorbed, and enabling the light to be reflected to the outside of the high-voltage LED chip through the emission enhancement film system jointly formed by the high-refractive-index material layer and the low-refractive-index material layer, improving the external quantum light extraction efficiency of the high-voltage LED chip, thereby enhancing the brightness of the high-voltage LED chip and improving the HDR effect at the application end.

[0061] Furthermore, based on the light extraction control method according to an embodiment of the present invention, the present invention proposes a second embodiment. Referring to Figure 9 , the step A11 further includes:

[0062] Step S111: Obtain a first parameter of the low-refractive-index material layer, and obtain the thickness to be coated of the high-refractive-index material layer according to the first parameter, a preset second parameter of the high-refractive-index material, and the peak wavelength of the high-voltage LED chip;

[0063] The first parameter includes the first refractive index and the first film thickness of the low-refractive-index material layer; the preset second parameter includes the second refractive index of the high-refractive-index material;

[0064] In one embodiment, the step S111 further includes:

[0065] Step A1111: Obtain the thickness to be coated of the high-refractive-index material layer according to the first refractive index, the first film thickness, the second refractive index, and the peak wavelength of the high-voltage LED chip.

[0066] In this embodiment, the first film thickness is the thickness of the low-refractive-index material layer, and both the first refractive index and the second refractive index are inherent properties of the material, that is, the refractive index of SiO2 and the refractive index of TiO2. Specifically, the refractive index of SiO2 is 1.45 and the refractive index of TiO2 is 2.4. In the present invention, the existing PV layer SiO2 is used as the low-refractive-index material, and TiO2 can be used as the high-refractive-index material. For the wavelength of the LED light-emitting chip, the thickness of each layer of the film system is designed so that

[0067] n h t h =n l t l =λ / 4;

[0068] Among them, n refers to the refractive index, h is the high-refractive-index material, in this example, h refers to TiO2, and the refractive index n h is about 2.4;

[0069] l is the low-refractive-index material, in this example, l refers to SiO2, and the refractive index n l is about 1.45, t refers to the thickness of each layer of coating, t h refers to the film thickness of TiO2, t l refers to the film thickness of SiO2, and λ refers to the peak wavelength of the high-voltage LED chip.

[0070] From the above formula, the thickness of the high-refractive-index material to be coated can be calculated. According to the above DBR principle, the optical thickness of each layer of material is 1 / 4 of the central reflection wavelength. By adjusting the refractive index and thickness of the DBR material, the reflectivity of the film system can reach more than 95%.

[0071] Step S112: Coat the high refractive index material on the side surface of the single cell chip in the high-voltage LED chip according to the to-be-coated thickness to form a high refractive index material layer.

[0072] In this embodiment, a PEVCD device (chemical vapor deposition device) can be used to deposit a TiO2 thin film on the high-voltage LED chip. Then, by introducing reaction gases and reasonably designing the proportion of reaction gases, the RF power of the PEVCD device, the pressure in the reaction chamber, and the temperature, the deposition rate, refractive index, and thickness of the TiO2 thin film can be precisely controlled. After depositing the TiO2 thin film using the PECVD device, the TiO2 is masked and etched with HF (hydrofluoric acid solution) by the graphic transfer method to etch the side surface of the single cell chip into the same shape as SiO2, forming a high-low refractive index DBR reflection-enhanced film system with the low refractive index material SiO2 below. This enables the light incident on the side wall of the high-voltage chip to change the light path and be reflected from the light-emitting surface, enhancing the brightness of the high-voltage LED. Additionally, in this invention, TiO2 is taken as an example of the high refractive index material, but those skilled in the art can also select other high refractive index materials according to requirements, as long as they can achieve a DBR film system with a high-low refractive index difference.

[0073] In this embodiment, by reasonably setting the coating thickness of the high refractive index material, a reflection-enhanced film system is precisely formed with the low refractive index material, realizing the reflection of light, which has high flexibility and a wide range of applications.

[0074] Further, based on the light extraction control method proposed in an embodiment of the light extraction control method of the present invention, a third embodiment of the present invention is proposed. Before step S10, it further includes:

[0075] Step A101: Epitaxially grow a Gan buffer layer, an N-GaN layer, an MQW quantum well layer, a P-GaN layer, and an ITO layer on the sapphire substrate in sequence;

[0076] Step A102: Etch the Gan buffer layer, the N-GaN layer, the MQW quantum well layer, the P-GaN layer, and the ITO layer with a mixed gas of CL2 / BCL3 to obtain the epitaxial layers of all the single cell chips;

[0077] In one embodiment, step A102 further includes:

[0078] Step A1021: Etch the Gan buffer layer, the N-GaN layer, the MQW quantum well layer, the P-GaN layer, and the ITO layer with a mixed gas of CL2 / BCL3 towards the chip substrate direction to expose part of the N-GaN layer;

[0079] Step A1022: Epitaxially grow electrode layers on the ITO layer and the P-GaN layer respectively to obtain the epitaxial layer of the single-cell chip.

[0080] In this embodiment, the LED chip can be cut by microfabrication etching technology to form individual single-cell chips, achieving mutual isolation between high-voltage LED chips in the LED epitaxial layer, and at the same time exposing part of the N-GaN layer for setting the N electrode.

[0081] Step A103: Coat a low-refractive-index material on the sapphire substrate and the epitaxial layer to form a low-refractive-index material layer, and obtain the high-voltage LED chip.

[0082] In this embodiment, a Gan buffer layer, an N-GaN layer, an MQW quantum well layer, a P-GaN layer, and an ITO layer are sequentially formed on the sapphire substrate by epitaxial growth to ensure mutual isolation between high-voltage LED chips. Then, electrode layers are epitaxially grown on the ITO layer and the P-GaN layer respectively, so that the P electrode is connected to the P-GaN layer, and the N electrode is connected to the N-GaN layer through the ITO layer, which is used to ensure that the single-cell chip in the high-voltage LED chip can emit light when an input driving voltage is applied. Additionally, after setting the P electrode and the N electrode, electrode interconnection between each adjacent single-cell chip needs to be performed by depositing metal, that is, connecting the N electrode in the single-cell chip to the P electrode in the adjacent single-cell chip to achieve the series connection of all single-cell chips, thereby realizing a high-voltage low-current driving form and improving the service life of the high-voltage LED chip. Among them, the deposited metal between the P electrode and the N electrode is a conductive metal.

[0083] The above is only the preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, is similarly included in the patent scope of the present invention.

Claims

1. A light output control method, characterized in that, The light-emitting control method includes the steps of: Coating a high-refractive-index material on the low-refractive-index material layer of a high-voltage LED chip to obtain a high-refractive-index material layer; Forming a reflective enhancement film system through the high-refractive-index material layer and the low-refractive-index material layer, so that the reflective enhancement film system reflects the received light to the outside of the high-voltage LED chip; The step of coating a high-refractive-index material on the low-refractive-index material layer of a high-voltage LED chip to obtain a high-refractive-index material layer includes: Coating a high-refractive-index material on the low-refractive-index material layer on the side of a single-cell chip in a high-voltage LED chip to obtain a high-refractive-index material layer located on the low-refractive-index material layer, where the number of the single-cell chips is multiple; Wherein, the single-cell chip includes 5 light-emitting surfaces, namely a top surface and four side surfaces, and the single-cell chips are arranged in sequence on the high-voltage LED chip, so that one side surface of the four side surfaces of the single-cell chip is opposite to one side surface of other single-cell chips, and the light emitted from the side surface irradiates the side surface of other single-cell chips; The single-cell chip further includes a sapphire substrate, and the epitaxial layer includes a GaN buffer layer, an N-GaN layer, an MQW quantum well layer, a P-GaN layer, an ITO layer and an electrode layer. Among them, the GaN buffer layer, the N-GaN layer, the MQW quantum well layer, the P-GaN layer and the ITO layer are epitaxially grown on the sapphire substrate in sequence. The P electrode passes through the low-refractive-index material layer and is disposed on the ITO layer and is connected to the P-GaN layer, and the N electrode passes through the low-refractive-index material layer and is disposed on the N-GaN layer; Wherein, the N electrode in one of any two adjacent single-cell chips is connected to the P electrode in the other single-cell chip, so that all the single-cell chips in the high-voltage LED chip are connected in series, and among them, the P electrode and the N electrode are interconnected by depositing metal.

2. The light extraction control method according to claim 1, wherein The step of coating a high-refractive-index material on the low-refractive-index material layer on the side of a single-cell chip in a high-voltage LED chip to obtain a high-refractive-index material layer located on the low-refractive-index material layer includes: Obtaining a first parameter of the low-refractive-index material layer, and obtaining a to-be-coated thickness of the high-refractive-index material layer according to the first parameter, a preset second parameter of the high-refractive-index material and the peak wavelength of the high-voltage LED chip; Coating the high-refractive-index material on the side of the single-cell chip in the high-voltage LED chip according to the to-be-coated thickness to form a high-refractive-index material layer.

3. The light extraction control method according to claim 2, wherein The first parameter includes a first refractive index and a first film thickness of the low-refractive-index material layer; the preset second parameter includes a second refractive index of the high-refractive-index material; The step of obtaining a to-be-coated thickness of the high-refractive-index material layer according to the first parameter, the preset second parameter of the high-refractive-index material and the peak wavelength of the high-voltage LED chip includes: Obtaining a to-be-coated thickness of the high-refractive-index material layer according to the first refractive index, the first film thickness, the second refractive index and the peak wavelength of the high-voltage LED chip.

4. The light extraction control method according to claim 1, characterized in that Before the step of coating a high refractive index material on the low refractive index material layer of the high-voltage LED chip to obtain a high refractive index material layer, the following steps are further included: Epitaxially grow a GaN buffer layer, an N-GaN layer, an MQW quantum well layer, a P-GaN layer, an ITO layer, and an electrode layer on a sapphire substrate in sequence; Etch the GaN buffer layer, the N-GaN layer, the MQW quantum well layer, the P-GaN layer, the ITO layer, and the electrode layer with a mixed gas of CL2 / BCL3 to obtain the epitaxial layers of all unit cells of the chip; Coat a low refractive index material on the sapphire substrate and the epitaxial layer to form a low refractive index material layer, and obtain the high-voltage LED chip.

5. The light extraction control method according to claim 1, wherein The low refractive index material is SIO2, and the high refractive index material is TiO2.

6. An outgoing light control device, characterized in that, The light extraction control device is applied to the light extraction control method according to any one of claims 1 to 5. The light extraction control device includes a high-voltage LED chip and a high refractive index material layer coated on the high-voltage LED chip. Among them, the high refractive index material layer and the low refractive index material layer in the high-voltage LED chip form a reflective enhancement film system.

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