Micro-LED chip structure capable of enhancing luminous efficiency

Abstract

A Micro-LED chip structure for enhancing luminous efficiency disclosed by the present invention comprises a driving backboard and a display module, the driving backboard and the display module are combined together in a bonding mode and then are electrically connected through an anode contact, the display module comprises an inverted trapezoidal pixel luminous tabletop, and the inverted trapezoidal pixel luminous tabletop is electrically connected with the driving backboard. The top light emitting area is increased through the inverted trapezoidal table-board structure, total internal reflection is reduced, and light escape is facilitated; a double-layer inorganic film clamping high-reflection metal structure is deposited on the side wall of the table top, the light emitting angle is reduced, light escape is enhanced, and meanwhile optical crosstalk isolation is achieved; a double-layer micro-lens structure is arranged at the top of the table top, the refractive index of an inner layer material, the refractive index of an outer layer material and the refractive index of air are decreased progressively while light rays are converged, light reflection is reduced, and therefore the transmissivity of the light rays emitted by the micro-lenses can be improved, and the light emitting efficiency of the Micro-LED structure is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of light-emitting diodes, and particularly relates to a Micro-LED chip structure for enhancing luminous efficiency. Background Art

[0002] Micro-LEDs are regarded as the next-generation technology to replace LCDs and OLEDs due to their high brightness, high resolution, low power consumption, long lifespan, etc., and have great potential especially in the fields of AR / VR, near-eye displays, wearable devices, etc. Against the backdrop of the rapid development of Micro-LED display technology, improving the light extraction efficiency has become the core issue for breaking through the commercialization bottleneck.

[0003] Currently, due to the high refractive index of the material, total internal reflection in Micro-LEDs is severe, and only about 30% of the photons can escape from the device surface. Most of the light is trapped inside the material to form a waveguide mode, resulting in low light extraction efficiency. In addition, as the pixel size shrinks to the micron level, the proportion of sidewall defects increases, non-radiative recombination significantly intensifies, and at the same time, the current crowding effect leads to local overheating, further reducing the device reliability and efficiency. Moreover, when used in augmented reality (AR), only the light within about ±15° can be utilized, while most of the Micro-LEDs emit light at large angles (±55°), resulting in low light energy utilization efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a Micro-LED chip structure for enhancing luminous efficiency, which solves the problem of low luminous efficiency of the existing Micro-LED structure.

[0005] The technical solution adopted by the present invention is: a Micro-LED chip structure for enhancing luminous efficiency, including a driving backplane. Above the driving backplane, a display module is electrically connected through an anode contact. The display module includes an inverted trapezoidal pixel light-emitting mesa. A double-layer inorganic film sandwiching a high-reflection metal structure is deposited on the sidewall of the inverted trapezoidal pixel light-emitting mesa. Above the inverted trapezoidal pixel light-emitting mesa, an inner micro-lens layer is deposited, and an outer micro-lens layer with a relatively reduced refractive index is deposited outside the inner micro-lens layer.

[0006] The characteristics of the present invention also lie in that The height of the inverted trapezoidal pixel light-emitting mesa is 1 - 1.2 μm, and the lateral dimension is less than 4 μm.

[0007] The material of the inverted trapezoidal pixel light-emitting mesa is a III-V group semiconductor material.

[0008] The thickness of the double-layer inorganic film sandwiching the high-reflection metal structure is 120 - 350 nm.

[0009] In the double-layer inorganic film sandwiching the high-reflection metal structure, the materials of the double-layer inorganic films are all selected from SiO2, TiO2, Al2O3, or SiN x, the material of the highly reflective metal is selected from Ag, Au or Al.

[0010] In the double-layer inorganic film sandwiching high-reflection metal structure, the materials of the double-layer inorganic film are SiO2 and TiO2, or the materials of the double-layer inorganic film are Al2O3 and SiN x .

[0011] The lateral dimension of the outer layer of the microlens is less than the distance between the midpoints of adjacent pixels and greater than the lateral dimension of the inverted trapezoidal pixel light-emitting mesa after depositing the double-layer inorganic film sandwiching high-reflection metal structure. The height of the outer layer of the microlens is 2.8 - 3.1 μm.

[0012] The materials of the inner layer and the outer layer of the microlens are both selected from SiO2, Al2O3, TiO2, Ta2O5 or Si3N4.

[0013] The materials of the inner layer and the outer layer of the microlens are TiO2 and SiO2, or the materials of the inner layer and the outer layer of the microlens are Si3N4 and SiO2.

[0014] The shapes of the inner layer and the outer layer of the microlens are both hemispherical, parabolic or cannonball-shaped.

[0015] The beneficial effects of the present invention are: 1) The inclined sidewalls of the inverted trapezoidal pixel light-emitting mesa can change the light propagation path, reduce the probability of total internal reflection, and facilitate the escape of light; the light-emitting surface area is increased compared with the regular trapezoidal mesa, thus increasing the top light-emitting ratio; at the same time, the bottom size is smaller than that of the regular trapezoidal mesa, and the corresponding bottom interval between pixels becomes wider, which is beneficial to the diffusion of current from the electrode to the mesa edge, reducing the current crowding phenomenon, and can improve the luminous efficiency and device life.

[0016] 2) Depositing a double-layer inorganic film sandwiching high-reflection metal structure on the sidewalls of the inverted trapezoidal pixel light-emitting mesa can converge the large-angle light emitted from the sidewalls, enhance the light escape while reducing the optical crosstalk.

[0017] 3) The double-layer microlens structure can converge the large-angle light and reduce the divergence angle of the light; at the same time, the refractive index of the inner layer material, the outer layer material and air decreases gradually, reducing the interface light reflection loss, so as to improve the transmittance of the light emitted from the microlens, and further improve the luminous efficiency of the Micro-LED structure. Description of the Drawings

[0018] Figure 1 is a schematic structural diagram of the Micro-LED chip structure for enhancing luminous efficiency of the present invention; Figure 2 is a comparison schematic diagram of the Micro-LED chip structure for enhancing luminous efficiency of the present invention with the conventional structure and the process structure; Figure 3 isFigure 2 Schematic diagram of light type simulation curves of different structures.

[0019] In the figure, 10. Driving backplane, 20. Display module, 30. Inverted trapezoidal pixel light-emitting mesa, 40. Double-layer inorganic film sandwiching high-reflection metal structure, 50. Inner layer of microlens, 60. Outer layer of microlens; 31. Positive trapezoidal pixel light-emitting mesa. Detailed implementation manners

[0020] The present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0021] The present invention provides a Micro-LED chip structure for enhancing luminous efficiency, as Figure 1 shown, which includes a driving backplane 10 and a display module 20. The driving backplane 10 is a CMOS integrated circuit with anode contacts thereon. The display module 20 is located above the driving backplane 10. There are metal vias at the lowermost layer of the display module 20 that communicate with the inverted trapezoidal pixel light-emitting mesa 30. The driving backplane 10 and the display module 20 are electrically connected between the anode contacts and the metal vias through hybrid alignment bonding or other bonding methods. The display module 20 includes an inverted trapezoidal pixel light-emitting mesa 30, a double-layer inorganic film sandwiching high-reflection metal structure 40, and a double-layer microlens structure.

[0022] The inverted trapezoidal pixel light-emitting mesa 30 is a III-V group semiconductor material, commonly GaN, GaAs. The height of the inverted trapezoidal pixel light-emitting mesa 30 is in the range of 1 - 1.2 μm, and the lateral dimension is less than 4 μm.

[0023] The double-layer inorganic film sandwiching high-reflection metal structure 40 is deposited on the sidewall of the inverted trapezoidal pixel light-emitting mesa 30, and is composed of a single-layer inorganic film, a high-reflection metal layer, and a single-layer inorganic film deposited in sequence on the sidewall of the inverted trapezoidal pixel light-emitting mesa 30, that is, a high-reflection metal is sandwiched between the double-layer inorganic films. The double-layer inorganic film materials are selected from SiO2, TiO2, Al2O3, SiN x , and the preferred combination is SiO2 / TiO2 or Al2O3 / SiN x , and the high-reflection metal materials are selected from one or more stacks of Ag, Au, and Al. The total thickness of the structural film layer is in the range of 120 - 350 nm.

[0024] The double-layer microlens structure is composed of an inner microlens layer 50 and an outer microlens layer 60. The inner microlens layer 50 is deposited above the inverted trapezoidal pixel light-emitting mesa 30, and the morphology of the microlens is formed through reflow and etching processes. The outer microlens layer 60 is deposited outside the inner microlens layer 50. The materials of the inner microlens layer 50 and the outer microlens layer 60 are both selected from inorganic oxides and inorganic nitrides such as SiO2, Al2O3, TiO2, Ta2O5, and Si3N4. However, it is necessary to ensure that the refractive index of the material of the inner microlens layer 50 is greater than that of the material of the outer microlens layer 60. The preferred combinations are TiO2 / SiO2 and Si3N4 / SiO2. The shapes of the inner microlens layer 50 and the outer microlens layer 60 are one of hemispherical, parabolic, or cannonball-shaped. The lateral dimension of the double-layer microlens is less than the distance between the midpoints of adjacent pixels and greater than the lateral dimension of the inverted trapezoidal pixel light-emitting mesa 30 after depositing the double-layer inorganic film sandwiching the high-reflection metal structure 40. The height of the double-layer microlens / outer microlens layer 60 is in the range of 2.8 - 3.1 μm.

[0025] To better understand the mechanism of improving the light extraction efficiency of this application, the following combines Figure 2 the results of the light pattern simulation curves corresponding to different structures in Figure 3 for a detailed description.

[0026] Currently, Micro-LEDs used in AR glasses on the market generally adopt a vertical structure, and the shape of the pixel light-emitting mesa is as Figure 2 shown by the positive trapezoidal pixel light-emitting mesa 31 in a. Under the same size, the top light-emitting area of the inverted trapezoidal pixel light-emitting mesa 30 proposed by the present invention is larger than that of the positive trapezoidal pixel light-emitting mesa 31, improving the proportion of light extraction; although the sidewall areas are equal, the sidewall inclination angle of the inverted trapezoidal pixel light-emitting mesa 30 is greater than 90°, which can change the light propagation path, reduce the probability of total internal reflection, and facilitate the escape of light; at the same time, the bottom space between the inverted trapezoidal mesa pixels is relatively wide, which is conducive to the diffusion of current from the electrode to the mesa edge, reducing the current crowding phenomenon, and can improve the light-emitting efficiency and device life. Figure 3 In Figure 2 a and Figure 2 b, it can also be seen from the light pattern curves that the light intensities in different directions are significantly increased.

[0027] Figure 2 Structure c adds a sidewall double-layer inorganic film sandwiching the high-reflection metal structure 40 on the basis of Figure 2 structure b. While achieving sidewall passivation, the reflective metal can reflect some of the light that was originally emitted at a large angle to the light-emitting surface for emission, reducing the emission angle and further enhancing the escape of light; in addition, the reflective metal on the sidewall can reduce the optical crosstalk between pixels and improve the contrast of the final image. Figure 3 In Figure 2 c, the emission angle of the light pattern curve is compared with Figure 2There is an obvious reduction in b, and the light intensity at a small angle is also enhanced.

[0028] In order to further improve the light energy utilization rate of micro-LEDs in an augmented reality (AR) device, based on the Figure 2 c structure, Figure 2 a microlens is added to d, which can converge light and reduce the probability of total internal reflection. For example, Figure 3 in Figure 2 the light intensity ratio within d ± 40° Figure 2 is doubled compared to c.

[0029] The gradual change in refractive index can reduce the light reflection loss at the interface. Therefore, based on the inner layer 50 of the microlens in Figure 2 d, a microlens outer layer 60 is added. For example, Figure 3 in Figure 2 the light intensity ratio within e ± 30° Figure 2 is enhanced again compared to the light intensity of d.

[0030] Embodiment 1 The present invention provides a Micro-LED chip structure for enhancing luminous efficiency, including a driving backplane 10 and a display module 20. The driving backplane 10 is a CMOS integrated circuit with an anode contact thereon. The display module 20 is located above the driving backplane 10. The lowermost layer of the display module 20 has a metal through hole communicating with an inverted trapezoidal pixel light-emitting mesa 30. The driving backplane 10 and the display module 20 are electrically connected between the anode contact and the metal through hole through a hybrid alignment bonding method. The display module 20 includes an inverted trapezoidal pixel light-emitting mesa 30, a double-layer inorganic film sandwiching a high-reflection metal structure 40, and a double-layer microlens structure.

[0031] The inverted trapezoidal pixel light-emitting mesa 30 is made of GaN material. The height of the inverted trapezoidal pixel light-emitting mesa 30 is 1 μm, and the lateral dimension is 2 μm.

[0032] The double-layer inorganic film sandwiching a high-reflection metal structure 40 is deposited on the sidewall of the inverted trapezoidal pixel light-emitting mesa 30 and is composed of a single-layer inorganic film, a high-reflection metal layer, and a single-layer inorganic film deposited sequentially on the sidewall of the inverted trapezoidal pixel light-emitting mesa 30, that is, a high-reflection metal is sandwiched between the double-layer inorganic films. The double-layer inorganic film material is selected from the combination of SiO2 / TiO2, and the high-reflection metal material is selected from Ag. The film layer thickness is SiO2 / Ag / TiO2 = 50 / 100 / 50 nm.

[0033] The double - layer microlens structure is composed of an inner microlens layer 50 and an outer microlens layer 60. The inner microlens layer 50 is located above the inverted trapezoidal pixel light - emitting mesa 30, and the outer microlens layer 60 is deposited outside the inner microlens layer 50. The materials of the inner microlens layer 50 and the outer microlens layer 60 are both selected from the combination of TiO2 / SiO2. The shapes of the inner microlens layer 50 and the outer microlens layer 60 are hemispherical. The lateral dimension of the double - layer microlens is less than the distance between the mid - points of adjacent pixels and greater than the lateral dimension of the inverted trapezoidal pixel light - emitting mesa 30 after depositing the double - layer inorganic film - sandwiching high - reflection metal structure 40. The height of the double - layer microlens is 2.8μm.

[0034] Example 2 The present invention provides a Micro - LED chip structure for enhancing luminous efficiency, including a driving backplane 10 and a display module 20. The driving backplane 10 is a CMOS integrated circuit with anode contacts thereon. The display module 20 is located above the driving backplane 10. There are metal vias in the lowermost layer of the display module 20 that communicate with the inverted trapezoidal pixel light - emitting mesa 30. The driving backplane 10 and the display module 20 are electrically connected between the anode contacts and the metal vias through a hybrid alignment bonding method. The display module 20 includes an inverted trapezoidal pixel light - emitting mesa 30, a double - layer inorganic film - sandwiching high - reflection metal structure 40, and a double - layer microlens structure.

[0035] The inverted trapezoidal pixel light - emitting mesa 30 is made of GaAs material. The height of the inverted trapezoidal pixel light - emitting mesa 30 is 1.2μm, and the lateral dimension is 4μm.

[0036] The double - layer inorganic film - sandwiching high - reflection metal structure 40 is deposited on the sidewall of the inverted trapezoidal pixel light - emitting mesa 30 and is composed of a single - layer inorganic film, a high - reflection metal layer, and a single - layer inorganic film deposited sequentially on the sidewall of the inverted trapezoidal pixel light - emitting mesa 30, that is, a high - reflection metal is sandwiched between the double - layer inorganic films. The materials of the double - layer inorganic films are selected from the combination of Al2O3 / SiN x , and the high - reflection metal material is selected from Au. The film layer thickness is Al2O3 / Au / SiN x = 20 / 50 / 60nm.

[0037] The double - layer microlens structure is composed of an inner microlens layer 50 and an outer microlens layer 60. The inner microlens layer 50 is located above the inverted trapezoidal pixel light - emitting mesa 30, and the outer microlens layer 60 is deposited outside the inner microlens layer 50. The materials of the inner microlens layer 50 and the outer microlens layer 60 are both selected from Si3N4 / SiO2. The shapes of the inner microlens layer 50 and the outer microlens layer 60 are parabolic. The lateral dimension of the double - layer microlens is less than the distance between the mid - points of adjacent pixels and greater than the lateral dimension of the inverted trapezoidal pixel light - emitting mesa 30 after depositing the double - layer inorganic film - sandwiching high - reflection metal structure 40. The height of the double - layer microlens is 3.1μm.

[0038] Example 3 The present invention provides a Micro-LED chip structure for enhancing luminous efficiency, including a driving backplane 10 and a display module 20. The driving backplane 10 is a CMOS integrated circuit with an anode contact thereon. The display module 20 is located above the driving backplane 10. The lowermost layer of the display module 20 has a metal via communicating with an inverted trapezoidal pixel light-emitting mesa 30. The driving backplane 10 and the display module 20 are electrically connected between the anode contact and the metal via through a hybrid alignment bonding method. The display module 20 includes an inverted trapezoidal pixel light-emitting mesa 30, a double-layer inorganic film sandwiching a high-reflection metal structure 40, and a double-layer microlens structure.

[0039] The inverted trapezoidal pixel light-emitting mesa 30 is made of GaN material. The height of the inverted trapezoidal pixel light-emitting mesa 30 is 1.1 μm, and the lateral dimension is 2 μm.

[0040] The double-layer inorganic film sandwiching a high-reflection metal structure 40 is deposited on the sidewall of the inverted trapezoidal pixel light-emitting mesa 30, and is composed of a single-layer inorganic film, a high-reflection metal layer, and a single-layer inorganic film sequentially deposited on the sidewall of the inverted trapezoidal pixel light-emitting mesa 30, that is, a high-reflection metal is sandwiched between the double-layer inorganic films. The double-layer inorganic film material is selected from the combination of SiO2 / TiO2, and the high-reflection metal material is selected from Al. The film layer thickness is SiO2 / Al / TiO2 = 100 / 150 / 100 nm.

[0041] The double-layer microlens structure is composed of a microlens inner layer 50 and a microlens outer layer 60. The microlens inner layer 50 is located above the inverted trapezoidal pixel light-emitting mesa 30, and the microlens outer layer 60 is deposited outside the microlens inner layer 50. The materials of the microlens inner layer 50 and the microlens outer layer 60 are both selected from the combination of TiO2 / SiO2. The shapes of the microlens inner layer 50 and the microlens outer layer 60 are cannonball-shaped. The lateral dimension of the double-layer microlens is less than the distance between the midpoints of adjacent pixels and greater than the lateral dimension of the inverted trapezoidal pixel light-emitting mesa 30 after depositing the double-layer inorganic film sandwiching a high-reflection metal structure 40. The height of the double-layer microlens is 3 μm.

[0042] Example 4 The present invention provides a Micro-LED chip structure for enhancing luminous efficiency, including a driving backplane 10 and a display module 20. The driving backplane 10 is a CMOS integrated circuit with an anode contact thereon. The display module 20 is located above the driving backplane 10. The lowermost layer of the display module 20 has a metal via communicating with an inverted trapezoidal pixel light-emitting mesa 30. The driving backplane 10 and the display module 20 are electrically connected between the anode contact and the metal via through a hybrid alignment bonding method. The display module 20 includes an inverted trapezoidal pixel light-emitting mesa 30, a double-layer inorganic film sandwiching a high-reflection metal structure 40, and a double-layer microlens structure.

[0043] The inverted trapezoidal pixel light-emitting mesa 30 is made of GaAs material. The height of the inverted trapezoidal pixel light-emitting mesa 30 is 1 μm, and the lateral dimension is 2 μm.

[0044] The double - layer inorganic film sandwiching a high - reflection metal structure 40 is deposited on the sidewall of the inverted trapezoidal pixel light - emitting mesa 30, and is composed of a single - layer inorganic film, a high - reflection metal layer, and a single - layer inorganic film deposited sequentially outward on the sidewall of the inverted trapezoidal pixel light - emitting mesa 30, that is, a high - reflection metal is sandwiched between the double - layer inorganic films. The double - layer inorganic film material is selected from the group Al2O3 / SiN x , and the high - reflection metal material is selected from Ag. The film layer thickness is Al2O3 / Ag / SiN x = 50 / 150 / 60nm.

[0045] The double - layer microlens structure is composed of a microlens inner layer 50 and a microlens outer layer 60. The microlens inner layer 50 is located above the inverted trapezoidal pixel light - emitting mesa 30, and the microlens outer layer 60 is deposited outside the microlens inner layer 50. The materials of the microlens inner layer 50 and the microlens outer layer 60 are both selected from the combination Si3N4 / SiO2. The shapes of the microlens inner layer 50 and the microlens outer layer 60 are hemispherical. The lateral size of the double - layer microlens is less than the distance between the mid - points of adjacent pixels and greater than the lateral size of the inverted trapezoidal pixel light - emitting mesa 30 after depositing the double - layer inorganic film sandwiching a high - reflection metal structure 40. The height of the double - layer microlens is 2.8μm.

[0046] Example 5 The present invention provides a Micro - LED chip structure for enhancing luminous efficiency, including a driving backplane 10 and a display module 20. The driving backplane 10 is a CMOS integrated circuit with an anode contact thereon. The display module 20 is located above the driving backplane 10. The lowermost layer of the display module 20 has a metal via communicating with the inverted trapezoidal pixel light - emitting mesa 30. The driving backplane 10 and the display module 20 are electrically connected between the anode contact and the metal via through a hybrid alignment bonding method. The display module 20 includes an inverted trapezoidal pixel light - emitting mesa 30, a double - layer inorganic film sandwiching a high - reflection metal structure 40, and a double - layer microlens structure.

[0047] The inverted trapezoidal pixel light - emitting mesa 30 is made of GaN material. The height of the inverted trapezoidal pixel light - emitting mesa 30 is 1.2μm, and the lateral size is 4μm.

[0048] The double - layer inorganic film sandwiching a high - reflection metal structure 40 is deposited on the sidewall of the inverted trapezoidal pixel light - emitting mesa 30, and is composed of a single - layer inorganic film, a high - reflection metal layer, and a single - layer inorganic film deposited sequentially outward on the sidewall of the inverted trapezoidal pixel light - emitting mesa 30, that is, a high - reflection metal is sandwiched between the double - layer inorganic films. The double - layer inorganic film material is selected from the group Al2O3 / SiN x , and the high - reflection metal material is selected from Al. The film layer thickness is Al2O3 / Al / SiN x = 20 / 50 / 50nm.

[0049] The double-layer microlens structure is composed of an inner microlens layer 50 and an outer microlens layer 60. The inner microlens layer 50 is located above the inverted trapezoidal pixel light-emitting mesa 30, and the outer microlens layer 60 is deposited outside the inner microlens layer 50. The materials of the inner microlens layer 50 and the outer microlens layer 60 are both selected from the combination of TiO2 / SiO2. The shapes of the inner microlens layer 50 and the outer microlens layer 60 are parabolic. The lateral dimension of the double-layer microlens is less than the distance between the midpoints of adjacent pixels and greater than the lateral dimension of the inverted trapezoidal pixel light-emitting mesa 30 after depositing the double-layer inorganic film sandwiching the high-reflection metal structure 40. The height of the double-layer microlens is 3.1 μm.

[0050] Example 6 The present invention provides a Micro-LED chip structure for enhancing luminous efficiency, including a driving backplane 10 and a display module 20. The driving backplane 10 is a CMOS integrated circuit with anode contacts thereon. The display module 20 is located above the driving backplane 10. The lowermost layer of the display module 20 has metal vias communicating with the inverted trapezoidal pixel light-emitting mesa 30. The driving backplane 10 and the display module 20 are electrically connected between the anode contacts and the metal vias through a hybrid alignment bonding method. The display module 20 includes an inverted trapezoidal pixel light-emitting mesa 30, a double-layer inorganic film sandwiching a high-reflection metal structure 40, and a double-layer microlens structure.

[0051] The inverted trapezoidal pixel light-emitting mesa 30 is made of GaAs material. The height of the inverted trapezoidal pixel light-emitting mesa 30 is 1.1 μm, and the lateral dimension is 2 μm.

[0052] The double-layer inorganic film sandwiching the high-reflection metal structure 40 is deposited on the sidewall of the inverted trapezoidal pixel light-emitting mesa 30 and is composed of a single-layer inorganic film, a high-reflection metal layer, and a single-layer inorganic film deposited sequentially on the sidewall of the inverted trapezoidal pixel light-emitting mesa 30, that is, a high-reflection metal is sandwiched between the double-layer inorganic films. The materials of the double-layer inorganic films are selected from the combination of SiO2 / TiO2, and the material of the high-reflection metal is selected from Al. The film thicknesses are SiO2 / Al / TiO2 = 50 / 100 / 80 nm.

[0053] The double-layer microlens structure is composed of an inner microlens layer 50 and an outer microlens layer 60. The inner microlens layer 50 is located above the inverted trapezoidal pixel light-emitting mesa 30, and the outer microlens layer 60 is deposited outside the inner microlens layer 50. The materials of the inner microlens layer 50 and the outer microlens layer 60 are both selected from the combination of Si3N4 / SiO2. The shapes of the inner microlens layer 50 and the outer microlens layer 60 are shell-shaped. The lateral dimension of the double-layer microlens is less than the distance between the midpoints of adjacent pixels and greater than the lateral dimension of the inverted trapezoidal pixel light-emitting mesa 30 after depositing the double-layer inorganic film sandwiching the high-reflection metal structure 40. The height of the double-layer microlens is 2.9 μm.

Claims

1. A Micro-LED chip structure for enhancing luminous efficiency, characterized in that, It includes a driving backplane (10), and a display module (20) is electrically connected above the driving backplane (10) through an anode contact. The display module (20) includes an inverted trapezoidal pixel light-emitting mesa (30). A double-layer inorganic film sandwiching a high-reflection metal structure (40) is deposited on the side wall of the inverted trapezoidal pixel light-emitting mesa (30). A micro-lens inner layer (50) is deposited above the inverted trapezoidal pixel light-emitting mesa (30), and a micro-lens outer layer (60) with a relatively reduced refractive index is deposited outside the micro-lens inner layer (50).

2. The Micro-LED chip structure for enhancing luminous efficiency according to claim 1, characterized in that, The height of the inverted trapezoidal pixel light-emitting mesa (30) is 1 to 1.2 μm, and the lateral dimension is less than 4 μm.

3. The Micro-LED chip structure for enhancing luminous efficiency as described in claim 1, characterized in that, The material of the inverted trapezoidal pixel light-emitting mesa (30) is a group III-V semiconductor material.

4. The Micro-LED chip structure for enhancing luminous efficiency according to claim 1, characterized in that, The thickness of the double-layer inorganic film sandwiching the high-reflection metal structure (40) is 120 to 350 nm.

5. The Micro-LED chip structure for enhancing luminous efficiency as described in claim 1, characterized in that, The materials of the double-layer inorganic membranes in the double-layer inorganic membrane sandwich high-reflection metal structure (40) are all selected from SiO2, TiO2, Al2O3 or SiN x , and the material of the high-reflection metal is selected from Ag, Au or Al.

6. The Micro-LED chip structure for enhancing luminous efficiency according to claim 5, wherein, In the double-layer inorganic film sandwiching high-reflection metal structure (40), the materials of the double-layer inorganic film are SiO2 and TiO2, or the materials of the double-layer inorganic film are Al2O3 and SiN x .

7. The Micro-LED chip structure for enhancing luminous efficiency according to claim 1, wherein The lateral dimension of the micro-lens outer layer (60) is less than the distance between the midpoints of adjacent pixels and greater than the lateral dimension of the inverted trapezoidal pixel light-emitting mesa (30) after depositing the double-layer inorganic film sandwiching the high-reflection metal structure (40). The height of the micro-lens outer layer (60) is 2.8 to 3.1 μm.

8. The Micro-LED chip structure for enhancing luminous efficiency according to claim 1, characterized in that, The materials of the micro-lens inner layer (50) and the micro-lens outer layer (60) are both selected from SiO2, Al2O3, TiO2, Ta2O5 or Si3N4.

9. The Micro-LED chip structure for enhancing luminous efficiency according to claim 8, wherein The materials of the micro-lens inner layer (50) and the micro-lens outer layer (60) are TiO2 and SiO2, or the materials of the micro-lens inner layer (50) and the micro-lens outer layer (60) are Si3N4 and SiO2.

10. The Micro-LED chip structure for enhancing luminous efficiency according to claim 1, wherein, The shapes of the micro-lens inner layer (50) and the micro-lens outer layer (60) are both hemispherical, parabolic or cannonball-shaped.

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