A light emitting diode and light purification method thereof

Abstract

In the embodiment of the present disclosure, a light-emitting diode and a light purification method thereof are provided, belonging to the technical field of light-emitting diodes. The light-emitting diode comprises: an epitaxial structure and a light purification layer plated on the epitaxial structure, and the light purification layer comprises: a first reflective layer and a plurality of light exit holes, the first reflective layer is plated on the epitaxial structure, and each of the light exit holes penetrates the first reflective layer, wherein the aperture size of the light exit hole is N times the wavelength of the preset exit light, and N is an integer greater than or equal to 1. The scheme of the present disclosure filters out unnecessary light through the first reflective layer, and uses the optical waveguide principle to form total reflection in the light exit hole channel, thereby deriving the required wavelength to achieve high color rendering, thereby improving the purity of light.

Description

Technical Field

[0001] The present disclosure relates to the technical field of light emitting diodes, and in particular to a light emitting diode and a light purification method thereof. Background Art

[0002] With the rapid development of light emitting diode technology, light emitting diodes are increasingly widely used in various fields. Under such a development situation, people have higher and higher requirements on the color of display devices, and many experts and scholars have continuously proposed new materials and new structures that help improve the purity of light.

[0003] For current white light LEDs, blue light is matched with YAG phosphor to obtain the required white light. Different wavelengths of blue light must be matched with different proportions of phosphor to obtain the same color of white light. For example, the ratio of phosphor required for mixed white light with a wavelength of 455nm and mixed white light with a wavelength of 450nm is different, so that the white light can be controlled at the color coordinate position of CIE X=0.33Y=0.33. Taking 450nm blue light as an example, it is a continuous wavelength and contains light between 442nm-458nm, but 450nm has the brightest brightness. The phosphor will be adjusted for 450nm to achieve the best effect, but the weaker 442nm light will also excite the white light generated by the phosphor, which will not be in the desired position of the color coordinate, resulting in the white light seen by the human eye to be colder in color. If 458nm is brighter, the white light will be warmer in color. Therefore, if the half-width of the LED light can be controlled to be narrower, such as between 448nm-452nm, the light that the human eye can perceive will not easily have a color cast. Because the way the three primary colors of micron-level LEDs are excited into white light is different from the traditional excitation method of blue light + YAG phosphor, the purer the required color, that is, the narrower the half-width, the higher the color rendering will be.

[0004] Therefore, the structure of the existing LED chip cannot meet the excitation requirements of micron-sized LEDs, and it is urgent to provide an optical structure that can improve the purity of LED light and reduce color deviation. Summary of the invention

[0005] In view of this, the embodiments of the present disclosure provide a light emitting diode and a light purification method thereof, which at least partially solve the problems existing in the prior art.

[0006] In a first aspect, an embodiment of the present disclosure provides a light-emitting diode, comprising: an epitaxial structure and a light purification layer plated on the epitaxial structure; wherein the light purification layer comprises: a first reflective layer and a plurality of light exit holes, the first reflective layer is plated on the epitaxial structure, and each of the light exit holes passes through the first reflective layer; wherein the aperture size of the light exit hole is N times the wavelength of a preset output light, and N is an integer greater than or equal to 1.

[0007] According to a specific implementation of the embodiment of the present disclosure, the first reflective layer is an Al layer.

[0008] According to a specific implementation of the embodiment of the present disclosure, the light purification layer also includes a second reflective layer, the second reflective layer is plated on the first reflective layer, and each of the light output holes penetrates the second reflective layer and the first reflective layer.

[0009] According to a specific implementation of the embodiment of the present disclosure, the second reflective layer is an AlN layer.

[0010] According to a specific implementation of the embodiment of the present disclosure, the height of the second reflective layer is greater than the height of the first reflective layer.

[0011] According to a specific implementation of the embodiment of the present disclosure, the first reflective layer is an AlN layer.

[0012] According to a specific implementation of the embodiment of the present disclosure, the light purification layer also includes a second reflective layer, the second reflective layer is plated on the first reflective layer, and each of the light output holes penetrates the second reflective layer and the first reflective layer.

[0013] According to a specific implementation of the embodiment of the present disclosure, the thickness of the second reflective layer is 20-40 um.

[0014] According to a specific implementation of the embodiment of the present disclosure, the light exit hole is a circular hole.

[0015] According to a specific implementation of the embodiment of the present disclosure, the wavelength of the output light of the light output hole is 458nm-462nm.

[0016] According to a specific implementation of the embodiment of the present disclosure, the distance between two adjacent light exit holes is not equal to N times the wavelength of the preset output light, where N is an integer greater than or equal to 1.

[0017] In a second aspect, the present disclosure provides a method for light purification of a light emitting diode, comprising:

[0018] forming a light purification layer on the epitaxial structure of the light emitting diode;

[0019] The light purification layer is patterned to generate a plurality of light exit holes, wherein each of the light exit holes penetrates the light purification layer, and the aperture size of the light exit hole is N times the wavelength of the preset output light, where N is an integer greater than 1 or equal to .

[0020] According to a specific implementation of the embodiment of the present disclosure, the step of forming a light purification layer on the epitaxial structure of the light-emitting diode includes:

[0021] Plating a first reflective layer on the epitaxial structure of the light-emitting diode;

[0022] A second reflective layer is plated on the first reflective layer to form a light purification layer.

[0023] According to a specific implementation of the embodiment of the present disclosure, patterning the light purification layer to generate a plurality of light exit holes includes:

[0024] The second reflective layer and the first reflective layer are patterned to generate a plurality of light exit holes, wherein each of the light exit holes penetrates the second reflective layer and the first reflective layer, and the aperture size of the light exit hole is N times the wavelength of the preset output light, where N is an integer greater than 1 or equal to.

[0025] The solution of the embodiment of the present disclosure filters out unnecessary light through the first reflective layer, and uses the optical waveguide principle to form total reflection in the light output hole channel, thereby deriving the required wavelength to achieve high color rendering and improve the purity of light. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A first state diagram of a light purification method for a light emitting diode provided in an embodiment of the present disclosure;

[0028] Figure 2 A second state diagram of a light purification method for a light emitting diode provided by an embodiment of the present disclosure;

[0029] Figure 3 A third state diagram of a light purification method for a light emitting diode provided by an embodiment of the present disclosure;

[0030] Figure 4 A fourth state diagram of a light purification method for a light emitting diode provided by an embodiment of the present disclosure;

[0031] Figure 5 A state diagram of a light purification method for a light emitting diode provided by another embodiment of the present disclosure;

[0032] Figure 6 for Figure 5 The state diagram of the light-emitting diode after etching the light hole;

[0033] Figure 7 A light path diagram of a light emitting diode provided in an embodiment of the present disclosure;

[0034] Figure 8 A top view of a light emitting diode provided in an embodiment of the present disclosure;

[0035] Fig. 9 A schematic structural diagram of a light emitting diode provided by another embodiment of the present disclosure;

[0036] Fig.10 A schematic diagram of the structure of a light emitting diode provided by another embodiment of the present disclosure;

[0037] Fig.11 A schematic diagram of the workflow of a light purification method for a light-emitting diode provided in an embodiment of the present disclosure.

[0038] In the figure:

[0039] 1-sapphire substrate, 2-u-GaN layer, 3-n-type GaN layer, 4-N-PAD, 5-P-type GaN, 6-MQW layer, 7-P-PAD, 8-first reflection layer, 9-second reflection layer, 10-light output hole. DETAILED DESCRIPTION

[0040] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0041] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.

[0042] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein may be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein may be implemented independently of any other aspect, and two or more of these aspects may be combined in various ways. For example, any number of aspects described herein may be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein may be used to implement this device and / or practice this method.

[0043] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present disclosure. The drawings only show components related to the present disclosure rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0044] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0045] The embodiment of the present disclosure provides a light purification method for a light emitting diode.

[0046] See also Figure 1 to Figure 6 , Fig.11 , a light purification method for a light-emitting diode provided in an embodiment of the present disclosure includes:

[0047] S101. Forming a light purification layer on the epitaxial structure of the light-emitting diode.

[0048] Optionally, the light purification layer may be formed on the epitaxial structure by evaporation or deposition.

[0049] Of course, in actual use, the light purification layer may be formed on the epitaxial structure of the light-emitting diode by other methods, which are not specifically limited here.

[0050] It should be understood that the light emitting diode is provided with an epitaxial structure (for example, the epitaxial structure includes a first-type semiconductor layer, a light emitting layer and a second-type semiconductor layer, which is not specifically limited herein).

[0051] As an embodiment, the epitaxial structure is removed from the substrate (or growth substrate) (that is, the substrate is peeled off by laser peeling, leaving the epitaxial structure); after removal, a photopurification layer is formed on the epitaxial structure by a vapor deposition or sputtering process.

[0052] S102. Pattern the light purification layer to generate a plurality of light output holes, wherein each of the light output holes penetrates the light purification layer, and the aperture size of the light output hole is N times the wavelength of the preset output light, where N is an integer greater than 1 or equal to .

[0053] The light purification layer is processed using a designed template, specifically etching a plurality of light exit holes in the light purification layer, and the light exit holes are designed to facilitate the extraction of required light. The aperture size of the light exit hole is N times the wavelength of the preset output light, where N is an integer greater than 1 or equal to.

[0054] The light-emitting diode obtained by the light purification method of the embodiment of the present disclosure filters out unnecessary light through the light purification layer, and uses the optical waveguide principle to form total reflection in the light output hole channel, thereby deriving the required wavelength to achieve high color rendering index and improve the purity of light.

[0055] In the embodiment of the present invention, the epitaxial structure includes a sapphire substrate 1, a U-type GaN (gallium nitride) layer, an n-type GaN layer 3, an MQW (multiquantum well) layer 6, a P-type GaN layer 5, an N-PAD4 (N-type electrode), and a P-PAD7 (P-type electrode). The epitaxial structure in this embodiment is only an example of an embodiment provided by the present invention. The epitaxial structure can also be in other forms, which are not specifically limited here.

[0056] In order to obtain the light purification structure of the embodiment of the present invention, refer to Figure 1 to Figure 6 First, the sapphire substrate 1 is removed by using a surface-emitting laser to obtain Figure 2 In the structure described above, removing the sapphire substrate 1 can reduce the adverse effects caused by the low heat dissipation efficiency of the sapphire substrate 1, and using a material with good heat dissipation effect as the light purification layer instead to improve the heat dissipation efficiency. Subsequently, the light purification layer structure is prepared on the outermost layer of the epitaxial structure. Specifically, the outermost layer of the epitaxial structure of the embodiment of the present invention is the u-GaN layer 2, and the light purification layer is prepared on the u-GaN layer 2.

[0057] Optionally, the optical purification layer includes a first reflection layer 8 and a second reflection layer 9. The first reflection layer 8 can be made of a material with high reflectivity, such as Al, mercury and other high reflectivity metals. The role of the first reflection layer in this structure is to filter out the unnecessary light here. In the embodiment of the present invention, Al is preferably used as the first reflection layer 8, considering the high reflectivity and low cost of Al, and the coating can be completed by evaporation technology. In the embodiment of the present invention, a layer of Al film is sputtered on the u-GaN layer 2 by sputtering coating, or an Al film is plated on the u-GaN layer 2 by E-GUN (electron gun) spraying. The thickness of the Al film is preferably 2000 to 3000, but of course it is not limited to this range. By coating the u-GaN layer 2 with an Al film, the unnecessary light is filtered out here. After the Al layer is completed, a second reflection layer 9 is plated on the Al layer by sputtering coating. The second reflection layer 9 is different from the first reflection layer 8 medium, and a substrate material with good heat dissipation performance such as AlN, SiC, and GaAs can be selected.

[0058] The light purification effect achieved in the disclosed embodiment is achieved by utilizing the principle of optical waveguides, that is, a guiding structure composed of a light transparent medium (such as quartz glass) for transmitting electromagnetic waves of optical frequencies. The transmission principle of the optical waveguide is that at the interface between media with different refractive indices, the phenomenon of total reflection of electromagnetic waves causes the light waves to be confined to the waveguide and a limited area around it for propagation. The principle of optical waveguides is utilized to derive the desired wavelength to achieve high color rendering. Because light is a type of electromagnetic wave, at a specific wavelength and a specific space, light will be confined to a specific space to achieve total reflection. Therefore, on the structure of the Al layer and the AlN layer obtained above, the desired image is defined by yellow light development exposure on the AlN layer. The desired image is the structure required for the light exit hole 10, and then the desired pattern is formed by etching, such as Figure 5 As shown, the depth of the light exit hole 10 obtained by etching is to penetrate the AlN and Al layers. The size of the light exit hole 10 needs to be designed according to the wavelength of the required output light, and its size is N times the wavelength of the light to be output. For example, the hole size in this case is 460nm. There are multiple light exit holes, and the multiple light exit holes are arranged at equal intervals. In addition, the distance between two adjacent light exit holes is not equal to N times of 460nm.

[0059] Based on the above light purification method, the embodiment of the present invention also provides a light emitting diode, such as Figures 4 to 8 As shown, the light-emitting diode includes: an epitaxial structure and a light purification layer plated on the epitaxial structure, the light purification layer includes: a first reflective layer and a plurality of light output holes, the first reflective layer is plated on the epitaxial structure, each of the light output holes passes through the first reflective layer, wherein the aperture size of the light output hole is N times the wavelength of the preset output light, and N is an integer greater than or equal to 1.

[0060] The solution disclosed in the present invention filters out unnecessary light through the first reflective layer 8, and uses the optical waveguide principle to form total reflection in the light output hole 10 channel, thereby deriving the required wavelength to achieve high color rendering and improve the purity of light.

[0061] In the embodiment of the present invention, the epitaxial structure includes a sapphire substrate 1 , a U-type GaN layer, an n-type GaN layer 3 , an MQW layer 6 , and a P-type GaN layer 5 .

[0062] It should be noted that the epitaxial structure in this embodiment is only an example of an embodiment provided by the present invention, and the epitaxial structure can also be in other forms. For example, in another embodiment, the epitaxial structure can also include a sapphire substrate, a U-type GaN layer, an N-type GaN layer, an MQW layer, an electron blocking layer and a P-type GAN layer, wherein the N-type GaN layer includes a thin N-GaN layer with a thin growth thickness and an N-GaN layer with a thick growth thickness. The thin N-GaN layer and the thick N-GaN layer grow alternately, or the thick N-GaN layer and the thin N-GaN layer grow alternately. The alternating growth cycle is 5 to 45 cycles, and the N-type GaN is doped with Si elements. The N-GaN layer blue light LED epitaxial structure using this structure can not only reduce the turn-on voltage, but also improve the antistatic ability, effectively improving the brightness of the LED.

[0063] Reference Figure 6 and Figure 7 The optical purification layer structure shown in the figure illustrates the formation of the optical path based on the structure. The light generated from the MQW layer 6 passes through the n-GaN layer 3 and the u-GaN layer 2 to reach the optical purification layer. The wavelength range of the light generated from the MQW layer 6 is 455nm to 465nm. At the optical purification layer, due to the addition of the first reflection layer, the light emitted from the u-GaN is reflected back at the first reflection layer 8. In order to obtain the required output light, the optical purification layer also includes a light output hole. The light output hole is obtained by etching the first reflection layer. By designing the light output hole, only the light that meets the output conditions at the light output hole 10 will be emitted from the light output hole 10. The light that can be emitted here is related to the size of the light output hole 10. For example, if the wavelength of the light to be derived is 460nm, the size of the light output hole 10 is set to an integer multiple of 460nm, and the wavelength of the emitted light can be limited to around 460nm, which is 458nm to 462nm. Therefore, the optical purification layer structure of the embodiment of the present invention can limit the wavelength of the front light to around 460nm. Because light achieves total reflection in a specific space, if you want to take out the required light, for the channels with a wavelength of 455nm or 465nm, neither of them is a total reflection condition. Therefore, under a certain path, light will be refracted from other angles or converted into heat energy due to no outgoing path due to refraction, that is, loss will occur, so that the wavelength of the front light is limited to around 460nm.

[0064] The first reflective layer 8 in the embodiment of the present invention is Al. The first reflective layer 8 may be made of a material with high reflectivity, such as Al, copper and other metals with high reflectivity.

[0065] In other embodiments, the epitaxial structure may not include a U-type GaN layer (i.e., an undoped gallium nitride layer). That is, the epitaxial structure includes a sapphire substrate 1, an n-type GaN layer 3, an MQW layer 6, and a P-type GaN layer 5. The first reflective layer is plated on the n-type GaN layer 3, and the light path is emitted from the MQW layer 6 through the n-GaN layer 3 to the light purification layer and finally to the human eye.

[0066] In another embodiment of the present invention, Figure 5 and Figure 6 As shown, the optical purification layer also includes a second reflective layer, which is plated on the first reflective layer, and each of the light exit holes penetrates the second reflective layer and the first reflective layer. The second reflective layer 9AlN can also be made of a substrate material with good heat dissipation performance such as SiC and GaAs. Removing the sapphire substrate 1 and selecting AlN improves the heat dissipation efficiency and reduces the impact of heat.

[0067] In addition, the thickness of the second reflective layer 9 is 20-40 um, preferably 30 um. It should be noted that the height of the second reflective layer is greater than the height of the first reflective layer. The thickness of the first reflective layer is preferably 2000-3000 um.

[0068] Furthermore, the shape of the light exit hole 10 is circular, and the circular light exit hole 10 is selected so that the light purification effect obtained by using the light purification structure of the embodiment of the present invention is better. Of course, other shapes of light exit holes 10 can also be selected in other embodiments, such as square light exit holes 10, hexagonal light exit holes 10, etc.

[0069] The solution of the embodiment of the present disclosure filters out unnecessary light through the first reflective layer, and uses the optical waveguide principle to form total reflection in the light output hole channel, thereby deriving the required wavelength to achieve high color rendering and improve the purity of light.

[0070] In another preferred embodiment, Fig. 9 As shown, the light emitting diode comprises: an epitaxial structure and a light purification layer plated on the epitaxial structure, the light purification layer comprises: a first reflective layer and a plurality of light exit holes, the first reflective layer is plated on the epitaxial structure, each of the light exit holes penetrates the first reflective layer, wherein the aperture size of the light exit hole is N times the wavelength of the preset output light, and N is an integer greater than or equal to 1. The first reflective layer is an AlN layer.

[0071] In this embodiment, AlN is selected as the first reflective layer. Similarly, the epitaxial structure includes a sapphire substrate 1, a U-type GaN layer, an n-type GaN layer 3, an MQW layer 6, and a P-type GaN layer 5. The light generated from the MQW layer 6 reaches the AlN reflective layer through the n-GaN layer 3 and the u-GaN layer 2. The wavelength range of the light generated from the MQW layer 6 is 455nm to 465nm. A part of the light passing through the AlN reflective layer will be reflected, so that the light emitted from the light exit hole is purified.

[0072] In addition, if Fig.10 As shown, in this embodiment, the light purification layer further includes a second reflective layer, the second reflective layer is plated on the first reflective layer, and each of the light exit holes penetrates the second reflective layer and the first reflective layer. The second reflective layer is an Al layer. And the height of the second reflective layer is less than the height of the first reflective layer.

[0073] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A light emitting diode, characterized in that: The light emitting diode comprises: an epitaxial structure and a light purification layer plated on the epitaxial structure; The optical purification layer includes: a first reflective layer and a plurality of light exit holes, the first reflective layer is plated on the epitaxial structure, and each of the light exit holes penetrates the first reflective layer; wherein the aperture size of the light exit hole is N times the wavelength of the preset output light, and N is an integer greater than or equal to 1; The hole size of the light exit hole is 460nm.

2. The light emitting diode according to claim 1, characterized in that: The first reflective layer is an Al layer.

3. The light emitting diode according to claim 2, characterized in that: The light purification layer also includes a second reflective layer, which is plated on the first reflective layer, and each of the light output holes penetrates the second reflective layer and the first reflective layer.

4. The light emitting diode according to claim 3, characterized in that: The second reflective layer is an AlN layer.

5. The light emitting diode according to claim 4, characterized in that: The height of the second reflective layer is greater than the height of the first reflective layer.

6. The light emitting diode according to claim 1, characterized in that: The first reflective layer is an AlN layer.

7. The light emitting diode according to claim 6, characterized in that: The light purification layer also includes a second reflective layer, which is plated on the first reflective layer, and each of the light output holes penetrates the second reflective layer and the first reflective layer.

8. The light emitting diode according to claim 7, characterized in that: The second reflective layer is an Al layer.

9. The light emitting diode according to claim 8, characterized in that: A height of the second reflective layer is smaller than a height of the first reflective layer.

10. A method for light purification of a light emitting diode, characterized in that: include: forming a light purification layer on the epitaxial structure of the light emitting diode; The light purification layer is patterned to generate a plurality of light exit holes, wherein each of the light exit holes penetrates the light purification layer, and the aperture size of the light exit hole is N times the wavelength of the preset output light, where N is an integer greater than 1 or equal to .

11. The method for light purification of a light emitting diode according to claim 10, characterized in that: The step of forming a light purification layer on the epitaxial structure of the light emitting diode comprises: Plating a first reflective layer on the epitaxial structure of the light-emitting diode; A second reflective layer is plated on the first reflective layer to form a light purification layer.

12. The method for light purification of a light emitting diode according to claim 11, characterized in that: The patterning of the light purification layer to generate a plurality of light exit holes comprises: The second reflective layer and the first reflective layer are patterned to generate a plurality of light exit holes, wherein each of the light exit holes penetrates the second reflective layer and the first reflective layer, and the aperture size of the light exit hole is N times the wavelength of the preset output light, where N is an integer greater than 1 or equal to.

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