Structure of high-brightness Micro LED chip

Abstract

The invention discloses a structure of a high-brightness Micro LED chip, and belongs to the technical field of display lighting devices. A plurality of blue light emitting pixels are arranged on the surface of the driving circuit; the upper ends of the blue light emitting pixels are covered with fluorescence conversion glass, the structure can enable the fluorescence conversion layer to achieve remote packaging, the fluorescence conversion layer is farther away from a heating center, the heat effect is lower, the light conversion efficiency and reliability are improved, and the used fluorescence conversion glass can keep a larger physical scale. When the fluorescent conversion glass is applied to a Micro LED chip, the fluorescent conversion efficiency is higher than that of a fluorescent powder material of which the size is reduced, and the process difficulty and the cost can be reduced by applying the fluorescent conversion glass to the Micro LED chip compared with fluorescent powder and other materials. In addition, the invention further discloses a micro-nano optical structure, the micro-nano optical structure is selected from at least one of a reflective retaining wall, a micro-lens array diaphragm and a coarsened light-emitting surface, and the micro-nano optical structure can further improve the light-emitting efficiency and reduce the power consumption.

Description

Technical Field

[0001] The present application relates to a structure of a high-brightness Micro LED chip, belonging to the technical field of display lighting devices. Background Art

[0002] Matrix LED headlights can accurately illuminate the road ahead in various situations, and each LED light-emitting element can independently adjust the brightness and switch on and off. When meeting cars or pedestrians at night, the matrix LED headlights will automatically turn off part of the lamp body to avoid danger to other vehicle drivers due to dazzle, which can improve the safety factor and driving experience of night driving. As the number of pixels in the matrix headlights increases, the light-emitting pixels are miniaturized to the size of Micro LED chips, so fluorescent conversion materials with finer particles are required. However, as the particle size of traditional fluorescent conversion materials such as phosphors decreases, the fluorescent conversion efficiency and reliability will decrease, affecting the power consumption of LED lamps. Summary of the invention

[0003] In order to solve the problem of high energy consumption and insufficient brightness in the existing technology of matrix LED lamps due to the corresponding reduction in the particle size of fluorescent conversion materials required as the size of Micro LED chips decreases, the present application provides a high-brightness Micro LED chip structure, which uses fluorescent conversion glass to replace traditional alternative phosphors, and combines micro-nano optical structures to convert part of the blue light into long-wavelength light, and then recombine the remaining unconverted blue light to achieve white light, thereby improving the brightness of the Micro LED chip and reducing power consumption.

[0004] This application adopts the following technical solutions:

[0005] According to one aspect of the present application, a structure of a high-brightness Micro LED chip is provided, characterized in that it includes a driving circuit with a plurality of blue light-emitting pixels arranged on the surface;

[0006] The upper ends of the plurality of blue light emitting pixels are covered with fluorescent conversion glass.

[0007] Optionally, the structure of the high-brightness Micro LED chip further includes a micro-nano optical structure;

[0008] The micro-nano optical structure is selected from at least one of a reflective baffle, a microlens array membrane, and a roughened light-emitting surface;

[0009] The microlens array film includes a microlens array and a refractive index adjusting material filled between the microlens arrays.

[0010] Optionally, the side surface of the reflective baffle wall is inclined and has an arc, and is in the shape of a focusing cup as a whole.

[0011] Optionally, the material of the microlens array is selected from SiO 2 、TiN、Al 2 O 3 、SiN x At least one of SiN x There is no strict limitation on x, for example, x can be any value among 0.5, 1, and 1.5.

[0012] Optionally, the refractive index of the microlens material is less than or equal to the refractive index of the fluorescence conversion glass.

[0013] Optionally, the refractive index of the refractive index adjusting material is 1.4-2.0.

[0014] Optionally, the refractive index adjusting material is selected from SiO 2 、Al 2 O 3 , glass or the like.

[0015] Optionally, the thickness of the microlens array membrane is 2-50 μm.

[0016] Optionally, the roughness of the roughened light-emitting surface is 5 to 500 nm.

[0017] Optionally, when the micro-nano optical structure is selected from a reflective baffle wall;

[0018] The reflective blocking wall is arranged on the driving circuit and is located in the gaps between a plurality of blue light emitting pixels so that the blue light emitting pixels are isolated from each other.

[0019] Optionally, when the micro-nano optical structure is selected from a microlens array membrane;

[0020] The microlens array film comprises a microlens array and a refractive index adjusting material filled between the microlens array;

[0021] The microlens array film is arranged between a plurality of blue light emitting pixels and the fluorescent conversion glass, and the microlenses in the microlens array correspond to the blue light emitting pixels one by one.

[0022] Optionally, when the micro-nano optical structure is selected from a reflective baffle and a microlens array membrane;

[0023] The reflective baffle is arranged on the driving circuit and is located in the gap between a plurality of blue light emitting pixels so that the blue light emitting pixels are isolated from each other;

[0024] The microlens array film is arranged between a plurality of blue light emitting pixels and the fluorescent conversion glass, and the microlenses in the microlens array correspond to the blue light emitting pixels one by one.

[0025] Optionally, the micro-nano optical structure is selected from a reflective baffle, a microlens array membrane and a roughened light-emitting surface;

[0026] The reflective baffle is arranged on the driving circuit and is located in the gap between a plurality of blue light emitting pixels so that the blue light emitting pixels are isolated from each other;

[0027] The microlens array film is covered and arranged between a plurality of blue light emitting pixels and the fluorescent conversion glass, and the microlenses in the microlens array correspond to the blue light emitting pixels one by one;

[0028] The side of the fluorescent conversion glass facing away from the blue light emitting pixel is a roughened light emitting surface.

[0029] Optionally, the blue light emitting pixel has a diameter of 5 to 50 μm, a pitch of 2 to 20 μm, and a height of 0.8 to 2 μm.

[0030] Optionally, the material of the fluorescence conversion glass is selected from aluminate materials, silicate materials, nitride materials (Si 3 N 4 , SiAlON, etc.), at least one of oxide materials, tungstate materials, molybdate materials, sulfide materials, phosphate materials, and borate materials.

[0031] Optionally, the thickness of the fluorescence conversion glass is 5 to 100 μm, the absorptivity of the excitation light is 20% to 70%, and the transmittance of the non-excitation light is greater than 70%.

[0032] Preferably, the thickness of the fluorescence conversion glass is 5-100 μm.

[0033] Preferably, the absorption rate of the fluorescence conversion glass to the excitation light is 30% to 60%, and the transmittance to the non-excitation light is greater than 80%.

[0034] Preferably, the thickness of the fluorescence conversion glass is 15-40 μm.

[0035] Preferably, the absorption rate of the fluorescence conversion glass to the excitation light is 35% to 60%, and the transmittance to the non-excitation light is greater than 85%.

[0036] The micro-nano optical structure in this application can further improve the light extraction efficiency and reduce power consumption. First, a reflective baffle is set in the gap between the pixels of the MicroLED chip to reflect the light emitted from the side and emit it from the front, thereby improving the light extraction efficiency and the collimation of the emitted light. The reflective baffle is made of materials with high reflectivity such as Ag, Al, Pt, Sn, In, etc. The bottom thickness of the reflective baffle is smaller than the width of the gap between the pixels of the Micro LED chip, and the top width is smaller than the bottom width, so that the side of the reflective baffle has an inclination angle or curvature. Preferably, the reflective baffle is made of Ag or Al, and the curvature of the reflective baffle constitutes a focusing cup structure. A microlens array is integrated on the light-emitting side of the Micro LED chip, and the material of the microlens array is SiO 2 、TiN、Al 2 O 3 、SiN x Etc. The light-emitting side of the fluorescent conversion glass is roughened to reduce total reflection and improve light output.

[0037] The beneficial effects of this application include:

[0038] The structure of the high-brightness Micro LED chip provided in the present application can enable remote packaging of the fluorescent conversion layer, which is farther away from the heat center and has a lower thermal effect, thereby improving the light conversion efficiency and reliability. The fluorescent conversion glass used can maintain a larger physical scale. In the application of Micro LED chips, the fluorescent conversion efficiency is higher than that of the phosphor material after the size is reduced. In addition, the application of fluorescent conversion glass in Micro LED chips can reduce the process difficulty and reduce costs compared with phosphors and other materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of a Micro LED chip device using fluorescent conversion glass as a light conversion layer provided by an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of a Micro LED chip device using fluorescent conversion glass as a light conversion layer and adding a reflective baffle structure provided in an embodiment of the present invention;

[0041] Figure 3 A schematic diagram of a Micro LED chip device using fluorescent conversion glass as a light conversion layer and adding a reflective baffle and a microlens array structure provided in an embodiment of the present invention;

[0042] Figure 4 Schematic diagram of a Micro LED chip device provided in an embodiment of the present invention, which uses a fluorescence conversion glass with a roughened light-emitting surface as a light conversion layer and adds a reflective baffle and a microlens array structure.

[0043] Reference numerals

[0044] 1. Driving circuit; 2. Blue light emitting pixel; 3. Fluorescent conversion glass; 4. Reflective baffle; 5. Microlens array; 6. Refractive index adjustment material; 7. Fluorescent conversion glass with roughened light output surface. DETAILED DESCRIPTION

[0045] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0046] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0047] Unless otherwise specified, conventional methods were used for testing and instrument settings were those recommended by the manufacturer.

[0048] The visible light non-absorption region transmittance test method and equipment is a UV-visible-near infrared absorption spectrometer, model: HATACHI / UH4150.

[0049] The source of Ce:YAG fluorescence conversion glass is self-made 300.

[0050] Example 1

[0051] High brightness Micro LED chip structure Figure 1 As shown, the GaN chip is located on the driving circuit (1) as a blue light emitting pixel (2), and the fluorescent conversion glass (3) covers the GaN chip.

[0052] The diameter of the GaN blue light-emitting pixel in the Micro LED chip is 30μm, and the spacing between pixels is 10μm. A 30μm thick Ce:YAG fluorescent conversion glass is placed above the light-emitting pixel. The Ce doping amount in the fluorescent conversion glass is 3%, and the transmittance in the visible light non-absorption area is 84%.

[0053] Example 2

[0054] High-brightness Micro LED chips with micro-nano optical structures (including reflective baffle structures), such as Figure 2 As shown, the GaN chip is located on the driving circuit (1) as a blue light emitting pixel (2), a reflective baffle (4) is provided in the gap between the GaN chips, and the fluorescent conversion glass (3) covers the GaN chip reflective baffle (4).

[0055] Among them, the diameter of the GaN blue light-emitting pixel in the Micro LED chip is 20μm, the spacing between pixels is 10μm, and the height is 1.5μm. A circular Ag reflective baffle is prepared in the pixel gap. The bottom thickness of the baffle is 7μm, the top thickness is 4μm, the side has a curvature, and the overall shape is a focusing cup with a height of 1.5μm. A 20μm thick Ce:YAG fluorescent conversion glass is placed above the luminous pixel. The Ce doping amount in the fluorescent conversion glass is 4%, and the transmittance in the visible light non-absorption area is 82%.

[0056] Example 3

[0057] High-brightness Micro LED chips with micro-nano optical structures (including reflective baffles and microlens array structures), such as Figure 3 As shown, the GaN chip is located on the driving circuit (1) as a blue light emitting pixel (2), a reflective baffle (4) is provided in the gap of the GaN chip, a microlens array (5) film covers the GaN chip reflective baffle (4), a refractive index adjusting material (6) is also filled in the gap of the microlens array, and a fluorescent conversion glass (3) covers the microlens array (5) film.

[0058] The diameter of the GaN blue light-emitting pixel in the Micro LED chip is 30μm, the pixel spacing is 20μm, and the height is 1.5μm. A circular Al reflective baffle is prepared in the pixel spacing. The bottom thickness of the baffle is 10μm, the top thickness is 4μm, the side has a curvature, and the overall shape is a focusing cup with a height of 3μm. A SiO 2 Microlens array, the diameter of the microlens unit is consistent with the diameter of the light-emitting pixel unit. Use a resin with a refractive index of 1.45 to fill the gaps between the spherical tops of the microlens array to make the surface flush, and place a 15μm thick Ce:YAG fluorescent conversion glass on top. The Ce doping amount in the fluorescent conversion glass is 4.5%, and the transmittance in the visible light non-absorption area is 78%.

[0059] Example 4

[0060] High-brightness Micro LED chips with micro-nano optical structures (including reflective baffles and microlens array structures and roughened light-emitting surfaces of fluorescent conversion glass), such as Figure 4 As shown, a GaN chip as a blue light emitting pixel (2) is located on a driving circuit (1), a reflective baffle (4) is provided in the gap of the GaN chip, a microlens array (5) film is covered on the GaN chip reflective baffle (4), a refractive index adjusting material (6) is also filled in the gap of the microlens array, and a fluorescent conversion glass (7) with a roughened light emitting surface is covered on the microlens array (5) film.

[0061] The diameter of the GaN blue light-emitting pixel in the Micro LED chip is 10μm, the spacing between pixels is 2μm, and the height is 1.5μm. A circular Ag reflective baffle is prepared in the pixel spacing. The bottom thickness of the baffle is 1.5μm, the top thickness is 0.5μm, the side has a curvature, and the overall shape is a focusing cup with a height of 1.5μm. Al 2 O 3 Microlens array, the diameter of the microlens unit is consistent with the diameter of the light-emitting pixel unit. Use a resin with a refractive index of 1.5 to fill the gaps between the spherical tops of the microlens array to make the surface flush, and place a 20μm thick Ce:YAG fluorescent conversion glass with a roughened light-emitting surface (roughening degree of 300nm) on top. The Ce doping amount in the fluorescent conversion glass is 4%, and the transmittance in the visible light non-absorption area is 83%.

[0062] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A high brightness Micro LED chip structure, characterized in that: It includes a driving circuit with a plurality of blue light emitting pixels arranged on the surface; The upper ends of the plurality of blue light emitting pixels are covered with fluorescent conversion glass.

2. The structure of the high brightness Micro LED chip according to claim 1, characterized in that: The structure of the high-brightness MicroLED chip also includes a micro-nano optical structure; The micro-nano optical structure is selected from at least one of a reflective baffle, a microlens array membrane, and a roughened light-emitting surface; The microlens array film includes a microlens array and a refractive index adjusting material filled between the microlens arrays.

3. The structure of the high brightness Micro LED chip according to claim 1, characterized in that: The side surface of the reflective retaining wall is inclined and has an arc, and is in the shape of a focusing cup as a whole; Preferably, the material of the microlens array is selected from SiO2, TiN, glass, Al2O3, SiN x At least one of; Preferably, the refractive index of the microlens material is less than or equal to the refractive index of the fluorescence conversion glass; Preferably, the refractive index of the refractive index adjusting material is 1.4 to 2.0; Preferably, the refractive index adjusting material is selected from at least one of SiO2, Al2O3, and glass; Preferably, the thickness of the microlens array membrane is 2 to 50 μm; Preferably, the roughness of the roughened light-emitting surface is 5-500 nm.

4. The structure of the high brightness Micro LED chip according to claim 2, characterized in that: When the micro-nano optical structure is selected from a reflective retaining wall; The reflective blocking wall is arranged on the driving circuit and is located in the gaps between a plurality of blue light emitting pixels so that the blue light emitting pixels are isolated from each other.

5. The structure of the high brightness Micro LED chip according to claim 2, characterized in that: When the micro-nano optical structure is selected from a microlens array membrane; The microlens array film comprises a microlens array and a refractive index adjusting material filled between the microlens array; The microlens array film is arranged between a plurality of blue light emitting pixels and the fluorescent conversion glass, and the microlenses in the microlens array correspond to the blue light emitting pixels one by one.

6. The structure of the high brightness Micro LED chip according to claim 2, characterized in that: When the micro-nano optical structure is selected from a reflective baffle and a microlens array membrane; The reflective baffle is arranged on the driving circuit and is located in the gap between a plurality of blue light emitting pixels so that the blue light emitting pixels are isolated from each other; The microlens array film is arranged between a plurality of blue light emitting pixels and the fluorescent conversion glass, and the microlenses in the microlens array correspond to the blue light emitting pixels one by one.

7. The structure of the high brightness Micro LED chip according to claim 2, characterized in that: When the micro-nano optical structure is selected from a reflective baffle, a microlens array membrane and a roughened light-emitting surface; The reflective baffle is arranged on the driving circuit and is located in the gap between a plurality of blue light emitting pixels so that the blue light emitting pixels are isolated from each other; The microlens array film is covered and arranged between a plurality of blue light emitting pixels and the fluorescent conversion glass, and the microlenses in the microlens array correspond to the blue light emitting pixels one by one; The side of the fluorescent conversion glass facing away from the blue light emitting pixel is a roughened light emitting surface.

8. The structure of the high brightness Micro LED chip according to claim 1, characterized in that: The blue light emitting pixel has a diameter of 5 to 50 μm, a pitch of 2 to 20 μm, and a height of 0.8 to 2 μm.

9. The structure of the high brightness Micro LED chip according to claim 1, characterized in that: The material of the fluorescence conversion glass is selected from at least one of aluminate materials, silicate materials, nitride materials, oxide materials, tungstate materials, molybdate materials, sulfide materials, phosphate materials, and borate materials.

10. The structure of the high brightness Micro LED chip according to claim 1, characterized in that: The thickness of the fluorescent conversion glass is 5-100 μm, the absorption rate of the exciting light is 20%-70%, and the transmittance of the non-exciting light is greater than 70%.

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