Multicolor micro-display chip based on color conversion

Abstract

The utility model relates to a multicolor micro-display chip based on color conversion. The multicolor micro-display chip comprises a mother pixel, a driving wafer, a first pixel layer and a second pixel layer, the mother pixel comprises at least four sub-pixels, at least two sub-pixels in the mother pixel have different light emitting colors, the number of the red sub-pixels is not less than 50% of the number of all the sub-pixels in the mother pixel, each red sub-pixel comprises an excitation pixel and a red light color conversion piece, and the sub-pixels are electrically connected with the driving wafer; the first pixel layer and the second pixel layer are stacked on the driving wafer in the Z direction, and excitation pixels are arranged in the first pixel layer; green sub-pixels and red light color conversion pieces are arranged in the second pixel layer, and each red light color conversion piece is in one-to-one correspondence with the excitation pixels. According to the utility model, the number of the red sub-pixels is effectively increased, so that the attenuation of red light in the mother pixels can be effectively controlled, and an ideal color display effect is further ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a multi-color micro-display chip based on color conversion. Background Art

[0002] In the field of LEDs, color displays are mainly composed of RGB three-color sub-pixels to form a mother pixel and perform combined light generation with different ratios. In theory, all colors on the spectrum can be generated by matching the three primary colors of red (R), green (G), and blue (B). Our perception of a certain color of an object is determined by the characteristics of the physical stimulation of the external object to the human eye on the one hand, and the visual characteristics of the human eye in processing the stimulation on the other hand. However, the final calibration of color must conform to the visual laws of the human eye. The human eye retina has two types of photoreceptor cells, namely cone cells and rod cells. Rod cells are used to perceive light intensity and mainly work in low-light environments. Cone cells are used to perceive colors and mainly work in high-light environments. Cone cells are further divided into three types: blue cone cells, green cone cells, and red cone cells. In order to enable the human eye retina to better perceive the corresponding colors, when performing light distribution on an LED display screen, the brightness of the three primary colors or two primary colors of red, green, and blue needs to reach a specific ratio to achieve an ideal color display effect.

[0003] However, in the field of micro-displays, for example, in the field of Micro-LED displays, the chip size is greatly reduced compared to conventional LED chips. As the size decreases, the brightness attenuation of red pixels is relatively serious. According to the conventional color pixel layout method, it is difficult to reach a specific brightness ratio, thus unable to achieve an ideal color display effect and meet the production and use requirements. Summary of the Utility Model

[0004] Therefore, the technical problem to be solved by the utility model is to overcome the defect of poor color display effect of micro-display chips in the prior art.

[0005] To solve the above technical problem, the utility model provides a multi-color micro-display chip based on color conversion, including:

[0006] A mother pixel, the mother pixel includes at least four sub-pixels, at least two sub-pixels in the mother pixel have different light-emitting colors, and there is a sub-pixel with a light-emitting color of red. The number of sub-pixels with a light-emitting color of red is not less than 50% of the total number of all sub-pixels in the mother pixel. Each sub-pixel with a light-emitting color of red includes an excitation pixel and a red light color conversion component. The red light color conversion component is located on the light-emitting path of the excitation pixel to form a sub-pixel with a light-emitting color of red;

[0007] A driving wafer, and all the sub-pixels are electrically connected to the driving wafer;

[0008] A first pixel layer, which is stacked on the driving wafer along the Z direction, and excitation pixels are provided in the first pixel layer;

[0009] A second pixel layer, which is stacked on the first pixel layer along the Z direction, and sub-pixels with a green light-emitting color and red light conversion components are provided in the second pixel layer. Each of the red light conversion components corresponds to an excitation pixel one by one.

[0010] In an embodiment of the present invention, filling holes are provided in the second pixel layer, and each of the filling holes is filled with the red light conversion component.

[0011] In an embodiment of the present invention, the length of the filling hole along the X direction is not less than the maximum length of the excitation pixel along the X direction, and the X direction is perpendicular to the Z direction.

[0012] In an embodiment of the present invention, an isolation layer is formed on the inner wall of the filling hole, and the isolation layer is a metal reflection layer or an absorbing layer.

[0013] In an embodiment of the present invention, the thickness of the isolation layer is 50 nm to 2 μm.

[0014] In an embodiment of the present invention, sub-pixels with a blue light-emitting color are further provided in the first pixel layer, and the excitation pixel also has a blue light-emitting color.

[0015] In an embodiment of the present invention, the excitation pixel, the sub-pixel with a blue light-emitting color, and the sub-pixel with a green light-emitting color are all trapezoidal or cylindrical.

[0016] In an embodiment of the present invention, an anode contact and a cathode contact are provided on the driving wafer. The excitation pixel, the sub-pixel with a blue light-emitting color, and the sub-pixel with a green light-emitting color all include a pixel body. The first pixel layer and the second pixel layer both include an insulating body. The pixel bodies in the first pixel layer and the second pixel layer are all coated inside the insulating body. A bonding metal part is provided on one side of each pixel body close to the driving wafer, and the bonding metal part is electrically connected to the corresponding anode contact. The outside of each pixel body is coated with an insulating passivation layer. The bonding metal part is located inside the insulating passivation layer. The upper part of the insulating passivation layer has an opening. The outside of the insulating passivation layer is coated with a common cathode layer. The pixel body is electrically connected to the common cathode layer through the opening, and the common cathode layer is used to be electrically connected to the cathode contact.

[0017] In one embodiment of the present utility model, the pixel main bodies each include a P-type semiconductor layer, an active layer, and an N-type semiconductor layer which are sequentially arranged along the Z direction. A bonding metal part is provided on one side of the P-type semiconductor layer close to the driving wafer, and the N-type semiconductor layer is electrically connected to the common cathode layer through the opening.

[0018] In one embodiment of the present utility model, the bonding metal parts of the sub-pixels with green light emission color in the second pixel layer are electrically connected to the corresponding anode contacts through the anode connecting parts passing through the first pixel layer. Anode holes corresponding to the anode connecting parts are provided in the first pixel layer, and the anode connecting parts are filled in the anode holes.

[0019] In one embodiment of the present utility model, the anode holes are formed on the interface between the first pixel layer and the second pixel layer. The top surface of the anode connecting part filled in the anode hole is lower than the interface to form a recessed part, and the bonding metal part of the sub-pixel with green light emission color is embedded in the recessed part of the corresponding anode hole in the first pixel layer to be in electrical contact with the anode connecting part; or,

[0020] The top surface of the anode connecting part filled in the anode hole is higher than the interface to form a protruding part, and the bonding metal part of the sub-pixel with green light emission color is fitted with the protruding part of the corresponding anode connecting part in the adjacent pixel layer below.

[0021] In one embodiment of the present utility model, cathode holes are further provided in the first pixel layer, cathode connecting parts are filled in the cathode holes, the cathode connecting parts are electrically connected to the cathode contacts, and the common cathode layers in the second pixel layer are electrically connected to the cathode contacts through the cathode connecting parts.

[0022] In one embodiment of the present utility model, the interface between the first pixel layer and the second pixel layer is also covered with the insulating passivation layer, the upper part of the insulating passivation layer at the interface is also covered with the common cathode layer, and a metal mesh grid layer is provided on the upper part of the common cathode layer.

[0023] In one embodiment of the present utility model, the light emitted by the sub-pixels with blue light emission color in the first pixel layer is emitted through the first notch in the first pixel layer. The first notch is formed on the metal mesh grid layer, and the length of the first notch in the X direction is greater than the top surface length of the corresponding sub-pixels with blue light emission color in the lower layer, wherein the X direction is perpendicular to the Z direction.

[0024] In one embodiment of the present utility model, the anode connecting part in the first pixel layer passes through an auxiliary pixel and is electrically connected to the corresponding anode contact on the driving wafer, and the auxiliary pixel is located in the first pixel layer.

[0025] In an embodiment of the present utility model, at least one lens is connected to the upper part of the second pixel layer, and the lenses and the mother pixels correspond one by one, or each lens and the sub-pixels correspond one by one.

[0026] The above technical solution of the present utility model has the following advantages compared with the prior art:

[0027] The multi-color microdisplay chip based on color conversion of the present utility model effectively increases the number of red sub-pixels, thereby effectively controlling the attenuation of red light in the mother pixels, and further ensuring an ideal color display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to make the content of the present utility model easier to be clearly understood, the present utility model will be further described in detail below according to the specific embodiments of the present utility model in conjunction with the drawings.

[0029] Figure 1 is the brightness curve diagram of a multi-color microdisplay chip based on color conversion of the present utility model;

[0030] Figure 2 is the first pixel distribution schematic diagram of the multi-color microdisplay chip of the present utility model;

[0031] Figure 3 is the second pixel distribution schematic diagram of the multi-color microdisplay chip of the present utility model;

[0032] Figure 4 is the comparison schematic diagram of trapezoidal sub-pixels and hemispherical sub-pixels;

[0033] Figure 5 is the overall structure diagram (top view) of the multi-color microdisplay chip of the present utility model;

[0034] Figure 6 is Figure 5 the partial enlarged view at A in;

[0035] Figure 7 is the internal structure diagram of the first mother pixel of the present utility model;

[0036] Figure 8 is Figure 7 the layout schematic diagram of the first pixel layer in;

[0037] Figure 9 is the internal structure diagram of the second mother pixel of the present utility model;

[0038] Figure 10 is Figure 9 the layout schematic diagram of the first pixel layer in;

[0039] Figure 11 is Figure 7Partial preparation flow chart of the shown chip;

[0040] Figure 12 is Figure 7 Preparation flow chart of the shown structure;

[0041] Explanation of reference numerals in the specification drawings:

[0042] 10, Mother pixel;

[0043] 20, Sub-pixel; 201, Pixel main body; 2011, P-type ohmic contact layer; 2012, P-type semiconductor layer; 2013, Active layer; 2014, N-type semiconductor layer; 2015, N-type ohmic contact layer;

[0044] 30, First pixel layer; 301, Insulating body; 302, Bonding metal part; 303, Insulating passivation layer; 3031, Opening; 304, Common cathode layer; 3041, Auxiliary hole; 305, Metal mesh grid layer; 3051, First notch; 306, Anode hole; 3061, Depression; 307, Anode connecting part; 3071, Protrusion; 308, Cathode hole; 309, Cathode connecting part; 310, Bonding layer;

[0045] 40, Second pixel layer; 401, Red light color conversion part; 402, Filling hole; 403, Isolation layer;

[0046] 50, Interface;

[0047] 60, Excitation pixel;

[0048] 70, Driving wafer; 701, Anode contact; 702, Cathode contact;

[0049] 80, Compound semiconductor; 801, Substrate; 90, Pixel array area; 100, Peripheral common cathode area; 110, Auxiliary pixel; 120, Lens. Detailed implementation manners

[0050] The present utility model will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present utility model and be able to implement it, but the described embodiments shall not be used as a limitation to the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and shall in no way be construed as a limitation to the present disclosure and its application or use.

[0051] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "vertical", "upper", "lower", "top", "side", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, the meaning of "a plurality" is two or more.

[0052] The following will combine Figures 1 - 12 to further describe the structure of this embodiment.

[0053] Embodiment 1

[0054] Refer to Figures 1 - 12 , this embodiment discloses a multi-color microdisplay chip based on color conversion, including a mother pixel 10, a driving wafer 70, a first pixel layer 30, and a second pixel layer 40;

[0055] The mother pixel 10 includes at least four sub-pixels 20. At least two sub-pixels 20 in the mother pixel 10 have different light-emitting colors, and there is a sub-pixel with a light-emitting color of red. The number of sub-pixels with a light-emitting color of red is not less than 50% of the total number of all sub-pixels in the mother pixel 10;

[0056] Each sub-pixel with a light-emitting color of red includes an excitation pixel 60 and a red light conversion component 401. The red light conversion component 401 is located on the light-emitting path of the corresponding excitation pixel 60 to use the light emitted by the excitation pixel 60 to excite the red light conversion component 401 to emit red light, thereby forming a sub-pixel with a light-emitting color of red;

[0057] As Figure 7 shown, the first pixel layer 30 is stacked on the driving wafer 70 along the Z direction, and excitation pixels 60 are provided in the first pixel layer 30;

[0058] The second pixel layer 40 is stacked on the first pixel layer 30 along the Z direction. Sub-pixels 20 with a light-emitting color of green and red light conversion components 401 are provided in the second pixel layer 40. Each red light conversion component 401 corresponds to an excitation pixel 60 one by one;

[0059] The above sub-pixels 20 are all electrically connected to the driving wafer 70, and the driving wafer 70 has a driving circuit to control the light emission of the sub-pixels 20 using the driving circuit; it can be understood that the sub-pixels with red light emission only need to electrically connect the excitation pixels 60 and the driving wafer 70.

[0060] The driving wafer 70 can adopt a CMOS driving wafer;

[0061] It should be noted that the light emission wavelength of the excitation pixel 60 is less than the red light wavelength, so as to use the light with a shorter wavelength to excite the red color conversion member 401 to generate color conversion and emit red light. The red color conversion member 401 adopts a quantum dot material or a red phosphor material.

[0062] Through the above structure, all the sub-pixels of the mother pixel 10 are respectively arranged in the corresponding pixel layers and can finally emit light of corresponding colors.

[0063] Furthermore, the number of sub-pixels with red light emission can be 50% - 90% of the total number of all sub-pixels in the mother pixel 10; specifically, it can also be 60%, 65%, 70%, 75%, 85%, etc.

[0064] In the above structure, by making the mother pixel include at least four sub-pixels and making the number of sub-pixels with red light emission greater than or equal to 50% of the total number of all sub-pixels in the mother pixel, the number of red sub-pixels is effectively increased, so that the attenuation of red light in the mother pixel can be effectively controlled, so that the brightness ratio of various colors can be maintained at a specific ratio, thus achieving an ideal color display effect.

[0065] Furthermore, as Figure 7 shown, the sub-pixels 20 with blue light emission are also arranged in the first pixel layer 30, and the light emission color of the excitation pixel 60 is also blue. This can make all the pixels in the first pixel layer 30 have blue light emission, which is more convenient for preparation. Only some pixels in this layer need to be used as the excitation pixels 60, and other pixels are used as the blue sub-pixels 20. No other sub-pixels are arranged on the light emission path above the blue sub-pixels 20, so that the blue light can be emitted through the second pixel layer 40. Then, the light finally emitted by the mother pixel 10 through the second pixel layer 40 includes blue light emitted by the blue sub-pixels 20, green light emitted by the green sub-pixels 20, and red light emitted by the red color conversion member 401, these three different colors of light.

[0066] In one of the embodiments, the light emission color of the excitation pixel 60 can also be different from that of the blue sub-pixels.

[0067] In the present utility model, the microdisplay chip has a Z direction, an X direction, and a Y direction, and the three directions are perpendicular to each other in pairs. Generally, the Z direction is the direction away from the driving wafer. In the present utility model, "up" and "down" are relative in the Z direction. Similarly, "top", "bottom", "high", and "low" are also relative in the Z direction.

[0068] For the convenience of description, the sub-pixel with a red light-emitting color is called a red sub-pixel, the sub-pixel with a green light-emitting color is called a green sub-pixel, and the sub-pixel with a blue light-emitting color is called a blue sub-pixel.

[0069] For example, as Figure 2 and Figure 3 shown, the mother pixel 10 includes four sub-pixels 20. Among the four sub-pixels 20, there are a red sub-pixel R, a green sub-pixel G, and a blue sub-pixel B. The red sub-pixel R is used to emit red light, the green sub-pixel G is used to emit green light, and the blue sub-pixel B is used to emit blue light. The microdisplay chip includes a plurality of mother pixels 10. The four sub-pixels 20 in each mother pixel 10 can be arranged in the Figure 2 shown RGRB manner, with one green sub-pixel G and one blue sub-pixel B each, and two red sub-pixels R distributed diagonally, or arranged in the Figure 3 shown RRGB manner, with one green sub-pixel G and one blue sub-pixel B each, and two red sub-pixels R arranged in a column in the Y direction; if the combination of the four sub-pixels still cannot meet the light distribution requirement of the red light, the surrounding sub-red sub-pixels can be further called for light distribution. For example, in Figure 2 , the mother pixel located in the lower right corner can call one red sub-pixel in the upper mother pixel for light distribution, or in Figure 3 , the mother pixel located in the lower left corner can call two red sub-pixels in the right mother pixel for light distribution.

[0070] Figure 1 is the brightness curve of the mother pixel 10. Figure 1 In it, "G" represents the brightness curve of the green sub-pixel, "B" represents the brightness curve of the blue sub-pixel, "R75%" represents the brightness curve of all the red sub-pixels with a quantity proportion of 75% in the mother pixel, "R50%" represents the brightness curve of all the red sub-pixels with a quantity proportion of 50% in the mother pixel, and "R25%" represents the brightness curve of all the red sub-pixels with a quantity proportion of 25% in the mother pixel. It can be seen from the Figure 1 shown brightness curve that when the number of red sub-pixels in the mother pixel is 50% or 75%, compared with 25%, the brightness curve moves upward and the overall brightness increases, thus effectively controlling the attenuation of the red light, being more conducive to ensuring the stability of light distribution, and thus achieving an ideal color display effect.

[0071] Understandably, the number of sub-pixels in a mother pixel can also be greater than four, and the specific number is not limited here.

[0072] Furthermore, the projections of all sub-pixels in the mother pixel 10 on the driving wafer do not overlap, so as to avoid light crosstalk between sub-pixels or color noise phenomena caused by photoexcitation to the greatest extent, thereby more precisely controlling the light combining effect.

[0073] Among them, the red sub-pixel is the whole composed of the excitation pixel 60 and the corresponding red light color conversion member 401. The projections of the excitation pixel 60 and the red light color conversion member 401 in the red sub-pixel on the driving wafer overlap with each other, which can make the two be coaxially arranged, so that the light emitted by the excitation pixel can reach the red light color conversion member well, thereby exciting the red light color conversion member to emit red light.

[0074] Figure 5 is a top view of the microdisplay chip. Each microdisplay chip includes a plurality of mother pixels 10 arranged in an array, forming a pixel array region 90, and a peripheral common cathode region 100 is provided on the periphery. Figure 6 is Figure 5 The partial enlarged view at A in Figure 7 is Figure 6 The cross-sectional view of the structure in Figures 8 - 10 at the a1-a2 path; the cross-sectional views of subsequent mother pixels, such as

[0075] In some embodiments, as Figure 7 shown, filling holes 402 are provided in the second pixel layer 40, and each filling hole 402 is filled with a red light color conversion member 401.

[0076] Furthermore, as Figure 9 shown, the inner wall of the filling hole 402 is inclined relative to the driving wafer 70, and the inclination angle C is 60° to 90°, so as to be more convenient for etching and ensure the filling effect at the same time.

[0077] In some embodiments, the length Ls of the filling hole 402 in the X direction is not less than the maximum length of the underlying excitation pixel 60 in the X direction, where the X direction and the Z direction are perpendicular. In this way, a good light channel can be provided for the underlying excitation pixel 60 and light crosstalk is not likely to occur, thereby ensuring the color conversion effect to the greatest extent.

[0078] In some embodiments, an isolation layer 403 is formed on the inner wall of the filling hole 402; the isolation layer 403 is used to shield the light interference from the pixels below the non-filling space, so that the color conversion member inside the filling hole can have a better color conversion effect.

[0079] The insulating layer 403 may be a metal reflective layer or a light absorbing layer.

[0080] The material of the metal reflective layer can be one or more of metals Al, Ti, Pt, Au, Cr and Ni, so as to shield light interference through metal reflection; the material of the light-absorbing layer can be carbon film, black glue, polysilicon and other light-absorbing materials, so as to shield light interference through light absorption.

[0081] Furthermore, the thickness of the insulating layer 403 is 50 nm to 2 um. If the thickness is too thin, leakage is likely to occur, while if the thickness is too thick, the cost will increase.

[0082] Specifically, the thickness required for light interference shielding can be achieved according to different materials, such as Al ≥ 50nm, black glue ≥ 1um.

[0083] In some embodiments, the red light color converter 401 can use quantum dot materials, such as indium phosphide (InP); it can also use phosphor materials, such as fluoride system phosphor - KSF red phosphor (K2SiF6:Mn4+), or nitride Eu2+ doped CaAlSiN3 based red phosphor.

[0084] In some embodiments, the excitation pixel 60 , the sub-pixel with a blue light-emitting color, and the sub-pixel with a green light-emitting color are all in a trapezoidal or cylindrical shape.

[0085] like Figure 7 As shown, the pixel is trapezoidal or cylindrical. Compared with the pixel of hemispherical structure or semi-ellipsoidal structure, the trapezoidal or cylindrical pixel can effectively increase the pixel luminous area, thereby increasing the luminous intensity. The pixel generally has an active layer to emit light. Figure 4 It can be seen that, given the same pixel base dimensions, the active layer area (the entire shaded area) of the trapezoidal pixel is larger than the active layer area of the hemispherical pixel (the shaded area within the hemisphere), effectively increasing the luminous intensity. Similarly, cylindrical pixels can also increase the active layer area compared to hemispherical pixels, effectively increasing luminous intensity.

[0086] In some embodiments, as Figures 7 - 8 As shown, an anode contact 701 and a cathode contact 702 are provided on the driver wafer 70. The excitation pixel, blue sub-pixel, and green sub-pixel all include a pixel body 201. The first pixel layer 30 and the second pixel layer 40 both include an insulating body 301. The pixel bodies 201 in the pixel layer are all enclosed within the insulating body 301. A bonding metal part 302 is provided on the side of each pixel body 201 close to the driver wafer 70. The bonding metal part 302 is electrically connected to the corresponding anode contact 701.

[0087] An insulating passivation layer 303 is coated outside each pixel body 201. The bonding metal part 302 is located inside the insulating passivation layer 303. The upper part of the insulating passivation layer 303 has an opening 3031. A common cathode layer 304 is coated outside the insulating passivation layer 303. The pixel body 201 is electrically connected to the common cathode layer 304 through the opening 3031, and the common cathode layer 304 is used to be electrically connected to the cathode contact 702.

[0088] The bonding metal parts 302 can correspond to the anode contacts 701 one by one, or multiple anode contacts 701 can correspond to one bonding metal part 302.

[0089] Among them, the pixel body 201 includes a P-type ohmic contact layer 2011, a P-type semiconductor layer 2012, an active layer 2013, and an N-type semiconductor layer 2014 that are sequentially arranged along the Z direction;

[0090] Among them, the active layer 2013 is used to emit light. Bonding metal parts 302 are arranged on one side of the P-type semiconductor layer 2012 close to the driving wafer 70. A P-type ohmic contact layer 2011 is arranged between the P-type semiconductor layer 2012 and the bonding metal part 302 to achieve ohmic contact between the P-type semiconductor layer 2012 and the bonding metal part 302. Finally, the P-type semiconductor layer 2012 is electrically connected to the corresponding anode contact 701 through the bonding metal part 302 to achieve anode connection; the N-type semiconductor layer is exposed at the opening 3031, and the exposed part is electrically connected to the common cathode layer 304. The common cathode layer 304 is used to be connected to the cathode contact 702 of the driving wafer 70 to achieve cathode connection. The insulating passivation layer 303 is used to insulate and isolate the N-type semiconductor layer 2014 and the P-type semiconductor layer 2012 in the pixel body to avoid short circuit.

[0091] Among them, the filling hole 402 is opened in the insulating body 301 of the second pixel layer 40.

[0092] In some embodiments, as Figure 8 shown, the height D of the pixel body 201 in the Z direction is 0.3um to 5um; preferably, D is 0.3um to 1.5um; among them, the height of the pixel body 201 is the distance between its P-type semiconductor layer 2012 and N-type semiconductor layer 2014 (including the thicknesses of the P-type semiconductor layer and N-type semiconductor layer themselves).

[0093] Furthermore, the inclination angle θ of the side wall of the pixel body 201 relative to the driving wafer 70 is 45° to 135°; it can be understood that the side wall of the pixel body 201 here refers to the wall surface between the top surface and the bottom surface of the pixel body 201;

[0094] The above-mentioned tilt angle can reduce total internal reflection and is more conducive to light extraction. Beyond this range, the light extraction efficiency will be reduced. In addition, due to limited horizontal space, a certain space needs to be reserved for subsequent processes. When the tilt angle is too small, the bottom surface of the pixel occupies too much horizontal space, which will increase the difficulty of arranging pixel pitches.

[0095] Preferably, the tilt angle θ of the side wall of the pixel body 201 relative to the driving wafer 70 is 75° to 105°, which has the best light extraction efficiency and the best pixel pitch design.

[0096] In some embodiments, the thickness of the P-type ohmic contact layer 2011 is 10 nm to 300 nm, and its material can be a transparent conductive thin film such as indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), etc., or a metal alloy thin film such as AuBe, AnZn, etc.

[0097] In some embodiments, the thickness of the insulating passivation layer 303 is 30 nm to 500 nm to better ensure the insulation and passivation capabilities.

[0098] In some embodiments, the thickness of the common cathode layer 304 is 50 nm to 500 nm to increase its transmittance as much as possible while ensuring the current spreading ability. The thicker the common cathode layer 304, the better the current spreading, but the lower the transmittance, which will cause greater light loss and increase the processing difficulty at the same time. If the thickness is too thin, it will affect the metal current spreading ability.

[0099] In some embodiments, the bonding metal part 302 of the sub-pixel with a green light-emitting color in the second pixel layer 40 is electrically connected to the corresponding anode contact 701 through the anode connecting part 307 passing through the first pixel layer 30. An anode hole 306 corresponding to the anode connecting part 307 is provided in the first pixel layer 30, and the anode hole 306 is filled with an anode metal material to form the anode connecting part 307, so as to realize the anode connection between the upper sub-pixel 20 and the driving wafer 70 through the anode connecting part 307.

[0100] Furthermore, the above-mentioned anode hole 306 is formed in the insulating body 301 of the first pixel layer 30.

[0101] In one of the embodiments, the top length (in the X direction) of the anode hole 306 is greater than the bottom length.

[0102] In one of the embodiments, as Figure 10 shown, the tilt angle φ of the inner wall of the anode hole 306 relative to the top surface of the driving wafer 70 is 90° to 120°.

[0103] Furthermore, the anode hole 306 can be trapezoidal; it can also be Y-shaped.

[0104] In some embodiments, an anode hole 306 is formed on the interface 50 between the first pixel layer 30 and the second pixel layer 40. As Figures 9 - 10 shown, the top surface of the anode connector 307 filled in the anode hole 306 is lower than the interface 50 to form a recessed portion 3061. The bonding metal part 302 of the green sub-pixel is embedded in the recessed portion 3061 of the corresponding anode hole 306 in the first pixel layer 30 to make electrical contact with the anode connector 307.

[0105] Or,

[0106] As Figures 7 - 8 shown, the top surface of the anode connector 307 filled in the anode hole 306 is higher than the interface 50 to form a protruding portion 3071. The bonding metal part 302 of the green sub-pixel is fitted with the protruding portion 3071 of the corresponding anode connector 307 in the adjacent pixel layer below; through this fitting method, the formation of bonding voids between the bonding metal part 302 and the anode connector 307 can be avoided. Bonding voids will lead to poor electrical transmission. Through the above-mentioned convex-concave fitting method, the above problems can be effectively avoided, ensuring excellent electrical transmission effect, and at the same time effectively increasing the connection stability and connection strength between the bonding metal part 302 and the anode connector 307.

[0107] Furthermore, as Figure 10 shown, the height h1 of the recessed portion 3061 is 10 nm to 300 nm. As Figure 8 shown, the height h2 of the protruding portion 3071 is 10 nm to 300 nm to better avoid bonding voids and ensure the electrical transmission effect. The above heights should not be too large, as too large a height will easily increase the process difficulty, and too small a height will not be able to better ensure the electrical transmission effect.

[0108] In one of the embodiments, the length of the top end of the anode connector 307 in the X direction is greater than the length of the bottom end, that is, it has a structure form of wider at the top and narrower at the bottom. When the length of the bottom end is the same, compared with the structure of narrower at the top and wider at the bottom, this shape of structure can obtain a thicker anode connector 307, thereby enhancing the anode electrical transmission ability.

[0109] In some embodiments, a cathode hole 308 is further provided in the first pixel layer 30. A cathode connector 309 is filled in the cathode hole 308. All the cathode connectors 309 are electrically connected to the cathode contact 702. The common cathode layer 304 in the second pixel layer 40 is electrically connected to the cathode contact 702 through the cathode connector 309.

[0110] The common cathode layer 304 of the first pixel layer 30 can be directly electrically connected to the cathode contact 702.

[0111] Further, a cathode hole 308 is also formed on the interface 50 between the first pixel layer 30 and the second pixel layer 40. The top surface of the cathode connection member 309 filled in the cathode hole 308 is lower than the interface 50 to form a recess, or the top surface of the cathode connection member 309 filled in the cathode hole 308 is higher than the interface 50 to form a protrusion. This is similar to the setting method of the anode connection member 307 and will not be elaborated here.

[0112] In some embodiments, an insulating passivation layer 303 is also covered on the interface 50 between the first pixel layer 30 and the second pixel layer 40. A common cathode layer 304 is also covered on the upper part of the insulating passivation layer 303 of the interface 50. A metal mesh grid layer 305 is provided on the upper part of the common cathode layer 304 to achieve the effect of enhancing the cathode current through the metal mesh grid layer 305.

[0113] Further, a metal mesh grid layer 305 is also provided on the outer periphery of the filling hole 402; a metal mesh grid layer 305 is also provided on the common cathode layer 304 in the first pixel layer 30.

[0114] Further, the metal mesh grid layer 305 can be made of one or more materials selected from Cr, Pt, Ti, Au, Al, Cu, TiN, and TaN.

[0115] In one of the embodiments, the thickness of the metal mesh grid layer 305 is 100 nm to 5000 nm. This thickness is relatively thin, increasing the distance between the metal mesh grid layer 305 and the upper bonding metal part 302, so that there is enough space between the metal mesh grid layer 305 and the upper bonding metal part 302 to fill the insulating body 301, effectively avoiding the risk of short circuit between the metal mesh grid layer and the upper bonding metal part, resulting in better insulation and higher safety.

[0116] In one of the embodiments, as Figure 9 shown, the light emitted by the blue sub-pixel 20 in the first pixel layer 30 is emitted through the first notch 3051 in the first pixel layer 30. The first notch 3051 is formed on the metal mesh grid layer 305. The length L1 of the first notch 3051 in the X direction is greater than the top surface length L2 of the corresponding blue sub-pixel in the lower layer, so that the light emitted by the sub-pixel in the lower layer can be emitted through the first notch 3051 to the greatest extent, improving the light extraction efficiency of the pixel.

[0117] It can be understood that the "corresponding blue sub-pixel" here refers to the blue sub-pixel 20 whose emitted light passes through the first notch 3051.

[0118] In the above method, a first notch 3051 is formed in the metal mesh layer 305 at the interface, that is, the metal mesh material in the first notch 3051 is removed, so as to reduce the shielding of the light emitted by the underlying sub-pixels by the metal mesh in the original notch, so that the light emitted by the sub-pixels in the underlying pixel layer does not have to pass through the metal mesh layer to be emitted, reducing light loss and enabling the bottom sub-pixels to have higher light extraction efficiency.

[0119] Further, the light emitted by the sub-pixels 20 with blue light-emitting color in the first pixel layer 30 is emitted after passing through the second notch and the first notch 3051 in the second pixel layer 40 in sequence. The second notch is formed in the common cathode layer 304, and the length of the second notch in the X direction is greater than the top surface length of the underlying sub-pixels 20 with blue light-emitting color corresponding to the lower layer.

[0120] It can be understood that the "sub-pixels corresponding to the blue light-emitting color" here refer to the blue sub-pixels whose emitted light passes through the second notch and the first notch 3051 in sequence.

[0121] In the above method, a second notch is formed in the common cathode layer 304 at the interface 50 between two adjacent pixel layers, that is, the common cathode material in the second notch is removed, so that the light emitted by the sub-pixels in the lower pixel layer does not have to pass through the common cathode to be emitted, further reducing light loss and enabling the bottom sub-pixels to have higher light extraction efficiency.

[0122] Among them, the common cathode layer 304 in each pixel layer is an integral body, and the second notch is equivalent to a hole formed in the common cathode layer 304.

[0123] The anode connection member 307 in the first pixel layer 30 can be arranged in the following two ways:

[0124] In one way, as Figure 10 shown, a space is left separately between two adjacent excitation pixels 60 in the X direction in the first pixel layer 30 to arrange the anode connection member 307, where the X direction and the Z direction are perpendicular to each other;

[0125] In another way, as Figure 8 shown, the original pixels are reserved as auxiliary pixels 110 between two adjacent excitation pixels 60 in the X direction in the first pixel layer 30, so that the anode connection member 307 in the first pixel layer 30 passes through an auxiliary pixel 110 and is electrically connected to the corresponding anode contact 701 on the driving wafer 70. This way can avoid re-preparing the first pixel layer 30, and can directly use the original single-layer monochromatic product, that is, the second pixel layer 40 can be directly stacked on the original single-layer product for use, and the preparation method is more rapid, and the cost of separately preparing the bottom pixel layer can be reduced.

[0126] Understandably, the anode connector 307 needs to pass through the common cathode layer 304 outside the auxiliary pixel 110 and the insulation passivation layer 303 in sequence and then be electrically connected to the anode contact of the driving wafer 70. To avoid contact between the anode connector 307 and the common cathode layer 304 outside the auxiliary pixel 110, as Figure 8 shown, an auxiliary hole 3041 is provided on the common cathode layer 304 for the anode connector 307 to pass through. The length L4 of the auxiliary hole 3041 in the X direction is greater than the length L5 of the opening 3031 of the top insulation passivation layer 303 of the auxiliary pixel.

[0127] In some embodiments, similar to the above method, the cathode connector 309 can also pass through another auxiliary pixel 110 in the first pixel layer 30 and then be electrically connected to the cathode contact 702 on the driving wafer 70.

[0128] As Figure 7 shown, there are two excitation pixels 60, two auxiliary pixels 110 (one is provided with an anode connector 307 and the other is provided with a cathode connector 309), and one blue sub-pixel in the first pixel layer 30. There are two red color conversion components 401 in the second pixel layer 40, and one green sub-pixel is arranged between the two red color conversion components 401.

[0129] It should be noted that after the auxiliary pixel 110 is penetrated by the anode connector 307 (or the cathode connector 309), the auxiliary pixel 110 cannot emit light normally and is only used as a connector.

[0130] In some embodiments, as Figure 7 shown, at least one lens 120 is connected to the upper part of the second pixel layer 40. When arranging the lens 120, the following two methods can be adopted. One is that the lens 120 corresponds to the mother pixel 10 one by one, and the other is that each lens 120 corresponds to the sub-pixel 20 one by one. This method can better collimate the emitted light of each sub-pixel 20 and further reduce the light interference in the mother pixel.

[0131] This embodiment also discloses a preparation method of the above multi-color microdisplay chip, including the following steps:

[0132] Step M1, preparing the driving wafer 70;

[0133] Step M2: The first pixel layer 30 and the second pixel layer 40 are stacked in sequence along the Z direction on the driving wafer 70, so that an excitation pixel 60 is provided in the first pixel layer 30, and a sub-pixel 20 with a green light output color and a red light color converter 401 are provided in the second pixel layer 40. Each red light color converter 401 corresponds one-to-one to the excitation pixel 60, and each red light color converter 401 is located on the light output path of the corresponding excitation pixel 60 to excite and form a sub-pixel with a red light output color, and the sub-pixels 20 are all electrically connected to the driving wafer 70 to utilize the driving wafer 70 to drive the sub-pixels 20 to emit light.

[0134] In one embodiment, after step M2, refer to Figure 12 In the intermediate stage f, a dielectric layer is deposited on the upper portion of the second pixel layer 40 and patterned and etched to form lenses 120. This ensures a one-to-one correspondence between the lenses 120 and the mother pixels 10, i.e., one mother pixel 10 corresponds to one lens 120. Alternatively, each lens 120 is configured to correspond to a sub-pixel 20, i.e., each sub-pixel 20 corresponds to a separate lens 120, so as to better collimate the light emitted from each sub-pixel 20 and further reduce light interference within the mother pixel.

[0135] In some embodiments, step M2 comprises:

[0136] Step M21: Figure 11 As shown, a compound semiconductor 80 is bonded to the driver wafer 70; for example, the compound semiconductor 80 can be bonded to the driver wafer 70 through a bonding layer 310;

[0137] The compound semiconductor 80 includes a P-type ohmic contact layer 2011, a P-type semiconductor layer 2012, an active layer 2013, an N-type semiconductor layer 2014, and a substrate 801, which are sequentially arranged away from the driver wafer. After the compound semiconductor 80 is bonded to the driver wafer 70, the substrate 801 needs to be removed to expose the N-type semiconductor layer 2014. Figure 11 In stage b, after removing the substrate 801 , an N-type ohmic contact layer 2015 may be provided on the N-type semiconductor layer 2014 ;

[0138] Furthermore, the thickness of the N-type ohmic contact layer 2015 is 10 nm to 300 nm, and its material can be a transparent conductive film such as indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), or a metal alloy film such as gold germanium alloy (AuGe) or gold nickel alloy (AuNi).

[0139] Preferably, the thickness of the N-type ohmic contact layer 2015 is 10 nm to 100 nm, so as to ensure ohmic contact while also having a high transmittance, thereby reducing light loss.

[0140] Step M22: Pattern etch the compound semiconductor 80 to obtain at least one group of pixels. In this group of pixels, there are excitation pixels 60 and sub-pixels 20 with a blue light-emitting color. Both the excitation pixels 60 and the sub-pixels 20 with a blue light-emitting color include pixel bodies 201. Each pixel body 201 is electrically connected to the corresponding anode contact 701 through the corresponding bonding metal part 302; each pixel body 201 corresponds to one bonding metal part 302; wherein, the bonding metal part 302 can be obtained by etching the bonding layer 310.

[0141] Step M23: Deposit an insulating passivation layer 303 outside the pixel body 201, and set an opening 3031 on the upper part of the insulating passivation layer 303 to expose the N-type semiconductor layer 2014 or the N-type ohmic contact layer 2015 of the pixel body 201.

[0142] Step M24: Deposit a common cathode layer 304 outside the insulating passivation layer 303, so that the pixel body 201 is electrically connected to the common cathode layer 304 through the opening 3031, and the common cathode layer 304 is used to be electrically connected to the cathode contact 702.

[0143] That is, the N-type semiconductor layer 2014 of the pixel body 201 is electrically connected to the cathode contact 702 through the common cathode layer 304 to achieve cathode connection.

[0144] Among them, only one cathode contact 702 can be set on the driving wafer 70, or the number of cathode contacts 702 can be determined according to needs.

[0145] Step M25: Fill an insulating body 301 outside the common cathode layer 304, so that all the pixel bodies 201 are located inside the insulating body 301, thereby obtaining the first pixel layer 30 as shown in stage c in Figure 12 as shown in stage c.

[0146] It can be understood that the insulating passivation layer 303 and the common cathode layer 304 outside the pixel body 201 are also located inside the insulating body 301.

[0147] Step M26: Bond another compound semiconductor 80 on the top of the first pixel layer 30, pattern etch the compound semiconductor 80 to obtain sub-pixels 20 with a green light-emitting color. The sub-pixels 20 with a green light-emitting color also include pixel bodies 201. The pixel bodies 201 are electrically connected to the corresponding anode contacts 701 through the corresponding bonding metal parts 302; then repeat steps M23 - M24.

[0148] Step M27: Fill the outside of the common cathode layer 304 with the insulating body 301 so that the pixel body 201 is located inside the insulating body 301. Then, set a filling hole 402 on the insulating body 301 and fill the filling hole 402 with a color conversion material to form a red light color conversion member 401, thereby completing the preparation of the second pixel layer 40. Refer to Figure 12 stage c - stage e in

[0149] It can be understood that the position of the filling hole 402 should be on the light output path of the excitation pixel 60 so that the light emitted by the excitation pixel 60 can pass through the red light color conversion member 401 in the hole, thereby exciting the red light color conversion member 401 to emit color conversion light to generate red light.

[0150] It can be understood that since the light output colors of the sub - pixels in the two pixel layers are different, the materials of the compound semiconductors used in the preparation of the two pixel layers are also different so that the light output colors of the compound semiconductors used are different.

[0151] For example, in the compound semiconductor 80, both the P - type semiconductor layer 2012 and the N - type semiconductor layer 2014 can adopt gallium nitride (GaN) materials, and the substrate 801 can adopt materials such as gallium nitride (GaN), silicon (Si), or sapphire (Sapphire).

[0152] In some embodiments, when preparing the first pixel layer 30, an anode hole 306 is also opened on the insulating body 301 of the first pixel layer 30, and an anode metal material is filled in the anode hole 306 to form an anode connection member 307, so as to realize the anode connection between the upper - layer green sub - pixel 20 and the driving wafer 70 through the anode connection member 307.

[0153] In some embodiments, when preparing the first pixel layer 30, a through - hole anode hole 306 is also prepared in the auxiliary pixel 110, and an anode metal material is filled in the anode hole 306 to form an anode connection member 307, so that the anode connection member 307 passes through the corresponding auxiliary pixel 110 and is electrically connected to the corresponding anode contact 701 on the driving wafer 70.

[0154] In one of the embodiments, the insulating passivation layer 303 can be made of one or more of alumina, silicon dioxide, and silicon nitride.

[0155] In one of the embodiments, the insulating body 301 can be made of one or more of silicon oxide, silicon nitride, silicon carbide (SiC), silicon carbonitride (SiCN), phosphate glass (PSG), and borophosphosilicate glass (BPSG).

[0156] In one embodiment, the common cathode layer 304 includes one or more of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide (AZO), aluminum-doped indium tin oxide, silver-doped indium tin oxide, and gold-doped indium tin oxide;

[0157] In one embodiment, the metal mesh grid layer 305 can be made of one or more of Cr, Pt, Ti, Au, Al, Cu, TiN, and TaN.

[0158] In one embodiment, the material of the anode connector 307 can be one or more of aluminum, copper, and tungsten.

[0159] Furthermore, the material of the cathode connector 309 can be the same as that of the anode connector 307, as long as it is a conductive material.

[0160] In one embodiment, the material of the bonding metal part 302 can be one of Al, Au, and Cu, or a laminated structure of Ni, Au, Cu, etc. and Sn, or a bonded laminate of Au and In, Ge, or a bonded laminate of Au and Si.

[0161] Furthermore, the above bonding metal part 302 can adopt the following structural form: Cr 2nm / Pt 50nm / Ti 10nm / Pt 50nm / Au 100nm / Sn 150nm / Au 50nm, where Cr is the adhesion layer and Pt / Ti / Pt is the barrier layer.

[0162] Through this embodiment, a chip structure with two pixel layers can be prepared. Finally, three different colors of light (red, green, and blue) can be emitted through the second pixel layer 40 to achieve a three-color configuration.

[0163] Embodiment 2

[0164] The difference between this embodiment and Embodiment 1 is that only the excitation pixels 60 are provided in the first pixel layer 30. At this time, there are only two colors of light emitted from the entire chip.

[0165] Furthermore, the light emitted from the excitation pixels 60 in the first pixel layer 30 is also blue. When the blue light emitted by the laser pixels passes through the corresponding red color conversion part 401 above, it will excite the red color conversion part 401 to emit red light. Then, the light finally emitted through the second pixel layer 40 of this structure is only the red light and the green light emitted by the green sub-pixels. At this time, the chip product is a two-color product.

[0166] The preparation method of the microdisplay chip in this embodiment is basically the same as that in Embodiment 1 and will not be elaborated here.

[0167] The microdisplay chip and its preparation method in the above embodiments effectively increase the number of red sub-pixels, thereby effectively controlling the attenuation of red light in the mother pixel, so that the brightness ratios of various colors can be maintained at a specific ratio, and further ensuring an ideal color display effect.

[0168] All the above optional technical solutions can be combined arbitrarily to form optional embodiments of the present utility model, that is, any number of embodiments can be combined to meet the requirements of different application scenarios, and all are within the protection scope of this application, and will not be elaborated one by one here.

[0169] It should be noted that the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or alterations can be made on the basis of the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or alterations derived therefrom are still within the protection scope of the present invention.

Claims

1. A multi-color microdisplay chip based on color conversion, characterized in that: including, a mother pixel, the mother pixel includes at least four sub-pixels, at least two sub-pixels in the mother pixel have different light-emitting colors, and there is a sub-pixel with a light-emitting color of red, the number of sub-pixels with a light-emitting color of red is not less than 50% of the total number of sub-pixels in the mother pixel, each sub-pixel with a light-emitting color of red includes an excitation pixel and a red light color conversion component, and the red light color conversion component is located on the light-emitting path of the excitation pixel to form a sub-pixel with a light-emitting color of red; a driving wafer, and each sub-pixel is electrically connected to the driving wafer; a first pixel layer, the first pixel layer is stacked on the driving wafer along the Z direction, and excitation pixels are arranged in the first pixel layer; a second pixel layer, the second pixel layer is stacked on the first pixel layer along the Z direction, and sub-pixels with a light-emitting color of green and red light color conversion components are arranged in the second pixel layer, and each red light color conversion component corresponds to an excitation pixel one by one.

2. The multi-color microdisplay chip based on color conversion according to claim 1, characterized in that: Filling holes are arranged in the second pixel layer, and each filling hole is filled with the red light color conversion component.

3. The multi-color microdisplay chip based on color conversion according to claim 2, wherein: The length of the filling hole in the X direction is not less than the maximum length of the excitation pixel in the X direction, and the X direction is perpendicular to the Z direction.

4. The multi-color microdisplay chip based on color conversion according to claim 2, characterized in that: An isolation layer is formed on the inner wall of the filling hole, and the isolation layer is a metal reflection layer or an absorption layer.

5. The multi-color microdisplay chip based on color conversion according to claim 4, characterized in that: The thickness of the isolation layer is 50 nm to 2 μm.

6. The multi-color microdisplay chip based on color conversion according to claim 1, wherein: Sub-pixels with a light-emitting color of blue are also arranged in the first pixel layer, and the light-emitting color of the excitation pixel is also blue.

7. The multi-color microdisplay chip based on color conversion according to claim 6, wherein: The excitation pixels, the sub-pixels with a light-emitting color of blue, and the sub-pixels with a light-emitting color of green are all trapezoidal or cylindrical.

8. The multi-color micro-display chip based on color conversion according to claim 6, wherein: An anode contact and a cathode contact are arranged on the driving wafer, the excitation pixels, the sub-pixels with a light-emitting color of blue, and the sub-pixels with a light-emitting color of green all include pixel bodies, the first pixel layer and the second pixel layer both include insulating bodies, the pixel bodies in the first pixel layer and the second pixel layer are all covered inside the insulating bodies, a bonding metal part is arranged on one side of each pixel body close to the driving wafer, the bonding metal part is electrically connected to the corresponding anode contact, an insulating passivation layer is covered outside each pixel body, the bonding metal part is located inside the insulating passivation layer, an opening is formed in the upper part of the insulating passivation layer, a common cathode layer is covered outside the insulating passivation layer, and the pixel body is electrically connected to the common cathode layer through the opening, and the common cathode layer is used for being electrically connected to the cathode contact.

9. The multi-color microdisplay chip based on color conversion according to claim 8, characterized in that: Each pixel body includes a P-type semiconductor layer, an active layer, and an N-type semiconductor layer arranged in sequence along the Z direction, the bonding metal part is arranged on one side of the P-type semiconductor layer close to the driving wafer, and the N-type semiconductor layer is electrically connected to the common cathode layer through the opening.

10. The multi-color microdisplay chip based on color conversion according to claim 8, characterized in that: The bonding metal part of the sub-pixel with a light-emitting color of green in the second pixel layer is electrically connected to the corresponding anode contact by an anode connecting part passing through the first pixel layer, anode holes corresponding to the anode connecting parts are arranged in the first pixel layer, and the anode connecting parts are filled in the anode holes.

11. The multi-color microdisplay chip based on color conversion according to claim 10, characterized in that: The anode hole is formed on the interface between the first pixel layer and the second pixel layer. The top surface of the anode connector filled in the anode hole is lower than the interface to form a recess. The bonding metal part of the sub-pixel with a green light-emitting color is embedded in the recess of the corresponding anode hole in the first pixel layer to be in electrical contact with the anode connector; or, The top surface of the anode connector filled in the anode hole is higher than the interface to form a protrusion. The bonding metal part of the sub-pixel with a green light-emitting color is fitted with the protrusion of the corresponding anode connector in the adjacent pixel layer below.

12. The multi-color microdisplay chip based on color conversion according to claim 8, wherein: Cathode holes are further provided in the first pixel layer. Cathode connectors are filled in the cathode holes. The cathode connectors are all electrically connected to cathode contacts. The common cathode layer in the second pixel layer is electrically connected through the cathode connectors and the cathode contacts.

13. The multi-color microdisplay chip based on color conversion according to claim 8, wherein: The interface between the first pixel layer and the second pixel layer is also covered with the insulating passivation layer. The upper part of the insulating passivation layer at the interface is also covered with the common cathode layer. A metal mesh grid layer is provided above the common cathode layer.

14. The multi-color microdisplay chip based on color conversion according to claim 13, wherein: The light emitted by the sub-pixel with a blue light-emitting color in the first pixel layer exits through the first notch in the first pixel layer. The first notch is formed on the metal mesh grid layer. The length of the first notch in the X direction is greater than the top surface length of the corresponding sub-pixel with a blue light-emitting color in the lower layer. Among them, the X direction is perpendicular to the Z direction.

15. The multi-color microdisplay chip based on color conversion according to claim 10, wherein: The anode connector in the first pixel layer passes through an auxiliary pixel and is electrically connected to the corresponding anode contact on the driving wafer. The auxiliary pixel is located in the first pixel layer.

16. The multi-color microdisplay chip based on color conversion according to claim 1, characterized in that: At least one lens is connected to the upper part of the second pixel layer. The lens corresponds to the mother pixel one by one, or each lens corresponds to the sub-pixel one by one.

Images