Microdisplay and near-eye display device

Abstract

The application provides a micro display and a near-eye display device, and relates to the technical field of micro display. The display comprises a driving back plate, a pixel electrode layer, a white light emitting functional layer, a thin film packaging layer and a color filter layer arranged along the light emitting direction; the pixel electrode layer comprises red, green and blue sub-pixel electrode areas, and the color filter layer comprises a composite metasurface unit corresponding to each sub-pixel electrode area; the composite metasurface unit comprises a full dielectric nanocolumn array, a transparent buffer isolation layer and a distributed Bragg reflection structure arranged along the light emitting direction; the structural parameters of the full dielectric nanocolumn array corresponding to different color sub-pixel electrode areas are different, and the film thickness parameters of the distributed Bragg reflection structure corresponding to different color sub-pixel electrode areas are different. The device can meet the color separation requirements of different color sub-pixels on the basis of retaining the silicon-based white light emitting functional layer, and reduce the light absorption loss and aging influence caused by the organic dye color filter.

Description

Technical Field

[0001] This application relates to the field of microdisplay technology, and more specifically, to a microdisplay and a near-eye display device. Background Technology

[0002] Silicon-based white OLED microdisplays form a high-density pixel array based on a driving backplane, featuring small size, high resolution, and fast response speed, and are widely used in near-eye display scenarios such as augmented reality and virtual reality.

[0003] Existing silicon-based white OLED microdisplays typically use continuously arranged white light-emitting functional layers to provide broadband light, and organic dye color filter layers are placed on the light-emitting sides of red, green, and blue sub-pixels for color separation. These filter layers primarily achieve color selection by absorbing non-target wavelengths, which easily leads to light energy loss and heat generation. Furthermore, organic dyes may age and experience transmission spectrum drift under long-term light and heat exposure, affecting display brightness and color stability. While separately depositing red, green, and blue light-emitting functional layers can reduce filter loss, the independent patterning and precise alignment processes are complex, and the manufacturing difficulty and yield risk increase significantly as pixel size shrinks further.

[0004] Dielectric metasurfaces can form structural colors by utilizing the resonance of subwavelength structures and the interference of multiple film layers. They have the characteristics of thin film layers, low absorption, and easy miniaturization. However, most existing metasurface filter structures are single nanoarrays or independent dielectric reflective films. They lack composite structures that are coordinated with silicon-based white OLED thin film encapsulation layers, RGB sub-pixel positions, and OLED microcavities, which easily lead to spectral distortion. Summary of the Invention

[0005] The purpose of this application is to address the shortcomings of the prior art by providing a microdisplay and near-eye display device that can meet the color separation requirements of different color sub-pixels while retaining the silicon-based white light emitting functional layer, and reduce the light absorption loss and aging effects caused by organic dye color filters.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: One aspect of this application provides a microdisplay, including a driving backplate, a pixel electrode layer, a white light emitting functional layer, a thin film encapsulation layer, and a color filter layer arranged sequentially along the light emission direction; the pixel electrode layer includes multiple sub-pixel electrode regions, including red sub-pixel electrode regions, green sub-pixel electrode regions, and blue sub-pixel electrode regions; the color filter layer includes composite metasurface units corresponding one-to-one with each sub-pixel electrode region; each composite metasurface unit includes an all-dielectric nanopillar array, a transparent buffer isolation layer, and a distributed Bragg reflection structure arranged sequentially along the light emission direction; the structural parameters of the all-dielectric nanopillar array corresponding to different colors of sub-pixel electrode regions are different, and the film thickness parameters of the distributed Bragg reflection structure corresponding to different colors of sub-pixel electrode regions are different.

[0007] Optionally, the thickness of the transparent buffer isolation layer corresponding to the sub-pixel electrode areas of different colors is different.

[0008] Optionally, the all-dielectric nanopillar array comprises multiple periodically arranged all-dielectric nanopillars, the height of which is greater than its lateral dimension.

[0009] Optionally, the height, lateral dimension, and array period of the all-dielectric nanopillars corresponding to the red, green, and blue sub-pixel electrode regions decrease sequentially.

[0010] Optionally, each distributed Bragg reflection structure includes 4 to 6 pairs of dielectric film layers, each pair consisting of an adjacent high-refractive-index dielectric layer and a low-refractive-index dielectric layer.

[0011] Optionally, in the same distributed Bragg reflection structure, the optical thicknesses of each high-refractive-index dielectric layer and each low-refractive-index dielectric layer satisfy the following: n H d H = n L d L = λ 0 / 4; where, λ 0 represents the design center reflection wavelength of the distributed Bragg reflector structure; n H The refractive index of the high-refractive-index dielectric layer at the design center reflection wavelength; n L The refractive index of the low-refractive-index dielectric layer at the design center reflection wavelength; d H The optical thickness of the high refractive index dielectric layer; d L The optical thickness of the low-refractive-index dielectric layer.

[0012] Optionally, a metal reflective layer is provided between the driving backplane and the pixel electrode layer.

[0013] Optionally, a black matrix is ​​provided between two adjacent composite metasurface units, and the projection of the black matrix along the thickness direction of the white light emitting functional layer is located between two adjacent sub-pixel electrode regions.

[0014] Optionally, the white light emitting functional layer includes an anode, a hole transport layer, a white light emitting layer, an electron transport layer, and a cathode arranged sequentially along the light emission direction, and the pixel electrode layer is electrically connected to the anode.

[0015] In another aspect of the embodiments of this application, a near-eye display device is provided, including a microdisplay as described in any of the above.

[0016] The beneficial effects of this application include: This application provides a microdisplay, comprising a driving backplate, a pixel electrode layer, a white light emitting functional layer, a thin film encapsulation layer, and a color filter layer arranged sequentially along the light emission direction. The pixel electrode layer includes multiple sub-pixel electrode regions, including red, green, and blue sub-pixel electrode regions. The color filter layer includes composite metasurface units corresponding to each sub-pixel electrode region. Each composite metasurface unit includes an all-dielectric nanopillar array, a transparent buffer isolation layer, and a distributed Bragg reflection structure arranged sequentially along the light emission direction. The structural parameters of the all-dielectric nanopillar array corresponding to different colors of sub-pixel electrode regions are different, and the film thickness parameters of the distributed Bragg reflection structure corresponding to different colors of sub-pixel electrode regions are different. This microdisplay retains a common white light emitting structure, and the differentiation of different colors is mainly achieved in the micro-nano structure on the light emission side, which helps to avoid the difficulties of fine evaporation and alignment caused by separately fabricating red, green, and blue emitting regions. Meanwhile, organic dye color filters are no longer used in the light output path. The color filter layer itself handles the structural color spectral dispersion, thus reducing the light absorption loss of organic dyes, avoiding transmittance and color changes caused by dye aging, and eliminating the need for spin coating, patterning, and film stacking of the corresponding organic color films. When each composite metasurface unit as a whole has a spectral response of transmission in the target band and reflection in the out-of-band band, some out-of-band light can also return towards the white light emitting functional layer and be reused, further reducing light loss. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a microdisplay provided in an embodiment of this application; Figure 2 This is one of the structural schematic diagrams of the white light emitting functional layer provided in the embodiments of this application; Figure 3 This is the second schematic diagram of the structure of the white light emitting functional layer provided in the embodiments of this application.

[0019] Icons: 10-Microdisplay; 11-Driver backplane; 12-Pixel electrode layer; 121-Red sub-pixel electrode area; 122-Green sub-pixel electrode area; 123-Blue sub-pixel electrode area; 13-White light emitting functional layer; 131-Anode; 132-Hole transport layer; 133-White light emitting layer; 1331-Monochrome light emitting sub-layer; 1332-Transition layer; 134-Electron transport layer; 135-Cathode; 136-Light emitting unit; 137-Connection layer; 14-Thin film encapsulation layer; 15-Color filter layer; 151-Composite metasurface unit; 1511-All-dielectric nanopillar array; 1512-Transparent buffer isolation layer; 1513-Distributed Bragg reflection structure; 16-Metallic reflective layer. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. It should be noted that, unless otherwise specified, the various features in the embodiments of this application can be combined with each other, and the combined embodiments are still within the protection scope of this application.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] Please refer to Figure 1 This application provides a microdisplay 10, including a driving backplate 11, a pixel electrode layer 12, a white light emitting functional layer 13, a thin film encapsulation layer 14, and a color filter layer 15 arranged sequentially along the light emission direction. The light emission direction refers to the general direction from the driving backplate 11 towards the outside of the color filter layer 15, used to describe the relative positions of each film layer, and does not indicate that all light rays in the device propagate in a straight line along this direction. The driving backplate 11 can be a silicon-based CMOS driving backplate, where CMOS is a complementary metal-oxide semiconductor. The driving backplate 11 contains a pixel driving circuit, which controls the light emission of the corresponding area of ​​each sub-pixel through the pixel electrode layer 12. The thin film encapsulation layer 14, also called a TFE layer, is used to seal the white light emitting functional layer 13, reducing the influence of water vapor and oxygen on the organic functional film layer and electrodes. A composite metasurface unit 151 is disposed on the light emission side of the thin film encapsulation layer 14, so that the color separation structure and the light-emitting structure are located on opposite sides of the encapsulation layer.

[0026] The pixel electrode layer 12 includes multiple sub-pixel electrode regions, and the color filter layer 15 includes composite metasurface units 151 that correspond one-to-one with each sub-pixel electrode region. It should be noted that the red sub-pixel electrode region 121, green sub-pixel electrode region 122, and blue sub-pixel electrode region 123 are electrode regions divided according to the final displayed color, not because the electrode material itself has red, green, and blue colors. The white light emitting functional layer 13 corresponding to each sub-pixel can provide broadband light containing multiple visible light bands, which is then separated by the different composite metasurface units 151 above. One-to-one correspondence means that each sub-pixel electrode region has a corresponding composite metasurface unit 151, so that the light emitted from the corresponding area of ​​the sub-pixel enters an optical structure that matches its displayed color, without requiring the outer contour of the sub-pixel electrode region to be exactly the same as that of the composite metasurface unit 151.

[0027] Each composite metasurface unit 151 includes an all-dielectric nanopillar array 1511, a transparent buffer layer 1512, and a distributed Bragg reflection structure 1513 arranged sequentially along the light emission direction. The nanopillar array provides a geometry-dependent resonant response, the distributed Bragg reflection structure 1513 comprises alternating layers of high-refractive-index and low-refractive-index dielectric layers, forming multilayer interference through the alternating stacking of these layers, and the transparent buffer layer 1512 determines the spacing and phase relationship between the two layers.

[0028] The all-dielectric nanopillar array 1511, corresponding to sub-pixel electrode regions of different colors, has different structural parameters, including at least one of nanopillar height, lateral dimension, cross-sectional shape, and array period. Similarly, the distributed Bragg reflection structure 1513, corresponding to sub-pixel electrode regions of different colors, has different film thickness parameters, including at least one of the film thickness of the high-refractive-index dielectric layer and the film thickness of the low-refractive-index dielectric layer. Therefore, spectral adjustment conditions can be configured for sub-pixels of different colors.

[0029] The aforementioned microdisplay 10 retains a shared white light-emitting structure, with the differentiation of different colors primarily achieved within the micro / nano structure on the light-emitting side. This helps avoid the difficulties of fine vapor deposition and alignment associated with separately fabricating red, green, and blue light-emitting regions. Simultaneously, organic dye color filters are no longer present in the light-emitting path; the color filter layer 15 itself handles structural color spectral dispersion. This reduces light absorption loss from organic dyes, avoids transmittance and color changes caused by dye aging, and eliminates the need for spin-coating, patterning, and film stacking of the corresponding organic color films. When each composite metasurface unit 151 exhibits a spectral response of transmission in the target wavelength band and reflection in the out-of-band band, some out-of-band light can also return towards the white light-emitting functional layer 13 for reuse, further reducing light loss.

[0030] Optionally, the all-dielectric nanopillar array 1511 includes a plurality of periodically arranged all-dielectric nanopillars, the height of which is greater than its lateral dimension.

[0031] All-dielectric refers to nanopillars whose main body is formed of a dielectric material, such as... Ta 2 O 5. The height of a nanopillar is the dimension along its axial direction, while the lateral dimension is the cross-sectional dimension perpendicular to the axial direction. For example, the lateral dimension of a cylindrical nanopillar is its diameter. For non-circular cross-sections, the maximum outer width can be used for characterization, and the same measurement rules should be applied when comparing nanopillars of different colors. The array period is the center-to-center spacing between adjacent repeating units along the arrangement direction, not the net gap between the surfaces of two nanopillars.

[0032] By giving the nanopillars a certain height within a relatively small lateral footprint, space for optical field confinement and phase adjustment can be provided without significantly increasing the subpixel planar area. The lateral dimensions of the nanopillars can be set to the order of hundreds of nanometers, thus adapting to ultra-small pixel layouts with pixel sizes no larger than 1 μm.

[0033] When the nanopillars are illuminated, an electromagnetic field distribution related to the material's refractive index, pillar size, and surrounding medium can be formed inside and around them. Under appropriate conditions, Mie resonance can be generated, thereby enabling phase modulation, polarization modulation, beam shaping, and compression of the device's light divergence angle, thus optimizing the pixel's light emission viewing angle and collimation characteristics. Combined with the color filter layer 15 above, this optimizes spectral characteristics and also improves the contrast, color purity, and center brightness of the microdisplay 10.

[0034] Optionally, the height, lateral dimension, and array period of the all-dielectric nanopillars corresponding to the red sub-pixel electrode region 121, the green sub-pixel electrode region 122, and the blue sub-pixel electrode region 123 are decreased sequentially.

[0035] The term "decreasing sequentially" here refers to comparing each of the three parameters individually. For example, the height of the nanopillar corresponding to the red sub-pixel is greater than that of the green sub-pixel, and the height of the nanopillar corresponding to the green sub-pixel is greater than that of the blue sub-pixel. The same comparison method is used for the lateral dimension and the array period.

[0036] For different colors, the microdisplay 10 of this application adjusts the resonance and scattering response of each sub-pixel by changing the column size and arrangement density of the nanopillars, rather than by adding dyes of different colors to achieve color separation. While satisfying overall optical matching, the differentiated all-dielectric nanopillar array 1511 can work together with the distributed Bragg reflection structure 1513 to adjust the emitted light spectrum and angular distribution, reduce stray color components, and increase the effective light emission ratio falling in the desired observation direction.

[0037] When using cylindrical nanopillars, the pillar height corresponding to the red sub-pixel electrode region 121 can be 320 nm, the diameter can be 160 nm, and the array period can be 380 nm; the pillar height corresponding to the green sub-pixel electrode region 122 can be 260 nm, the diameter can be 130 nm, and the array period can be 320 nm; the pillar height corresponding to the blue sub-pixel electrode region 123 can be 220 nm, the diameter can be 100 nm, and the array period can be 260 nm.

[0038] Optionally, each distributed Bragg reflection structure 1513 includes 4 to 6 pairs of dielectric film layers, each pair of dielectric film layers consisting of an adjacent high-refractive-index dielectric layer and a low-refractive-index dielectric layer.

[0039] The Distributed Bragg Reflection Structure (DBR), also known as 1513, derives its reflection from the combined action of multiple medium interfaces, rather than relying on the reflection of a single surface. Light undergoes partial reflection at each interface, and the light returning from different interfaces superimposes according to their phase relationship, thus forming a strong reflection response in a certain wavelength band. The refractive index of the high-refractive-index medium layer is greater than that of the low-refractive-index medium layer. For example, the high-refractive-index medium layer can be selected from... TiO 2. Ta 2 O 5 or Si 3 N 4. Low refractive index dielectric layer can be selected SiO 2. This allows for the formation of alternating film layers made of different materials.

[0040] Each distributed Bragg reflector structure 1513 can employ 4, 5, or 6 pairs of dielectric layers; for example, 4 pairs of layers contain 8 alternating dielectric layers. For structures with the same material and design wavelength, increasing the number of dielectric layer pairs generally enhances reflection within the designed reflection band, but it also increases the total film thickness and processing burden; therefore, more layers are not always better. Setting the number of dielectric layer pairs within the aforementioned range allows for a balance between spectral selection, device thickness, and film processing.

[0041] By designing film thickness differences in different color regions, the spectral response characteristics of each distributed Bragg reflector structure 1513 can be matched to the red, green, and blue light emission bands, respectively. This selectively modulates the light reflection and transmission of the corresponding sub-pixel emission bands, suppresses optical crosstalk between pixels, and improves the purity of the emitted light color. Simultaneously, it couples with the underlying all-dielectric nanopillar array 1511 to form a composite optical resonant system, controlling the light field distribution and optimizing the emitted light spectrum.

[0042] Optionally, in the same distributed Bragg reflection structure 1513, the optical thicknesses of each high-refractive-index dielectric layer and each low-refractive-index dielectric layer satisfy the following: n Hd H = n L d L = λ 0 / 4 in, λ 0 represents the design center reflection wavelength of the distributed Bragg reflector structure 1513; n H The refractive index of the high-refractive-index dielectric layer at the design center reflection wavelength; n L The refractive index of the low-refractive-index dielectric layer at the design center reflection wavelength; d H The optical thickness of the high refractive index dielectric layer; d L The optical thickness of the low-refractive-index dielectric layer.

[0043] The above relationship is a quarter-wavelength design relationship based on normal incidence, which ensures that the reflected light from each film layer interface forms a favorable phase superposition near the design wavelength. For example, the distributed Bragg reflection structure 1513 corresponding to the red, green, and blue sub-pixels can all use four pairs of dielectric film layers, with the design center reflection wavelengths being 620 nm, 530 nm, and 460 nm, respectively. Calculated from the above relationship, the optical thicknesses of each dielectric film layer are 155 nm, 132.5 nm, and 115 nm, respectively. The actual physical thickness is determined by dividing the corresponding optical thickness by the refractive index of the material at the design wavelength.

[0044] Optionally, the thickness of the transparent buffer isolation layer 1512 corresponding to the sub-pixel electrode areas of different colors is different.

[0045] The transparent buffer isolation layer 1512 is a light-transmitting dielectric film layer located between the all-dielectric nanopillar array 1511 and the distributed Bragg reflection structure 1513, and its thickness is the film layer dimension measured along the thickness direction of the device. This film layer is used to isolate the all-dielectric nanopillar array 1511 and the distributed Bragg reflection structure 1513, relieve interlayer stress, prevent interdiffusion at the film interface, precisely control the optical path between the all-dielectric nanopillar array 1511 and the distributed Bragg reflection structure 1513, optimize the resonance matching conditions, and provide a flat substrate for the patterned fabrication of nanopillars.

[0046] Under near-normal propagation conditions, its optical thickness can be represented by the product of the material's refractive index and physical thickness. Therefore, even if the red, green, and blue sub-pixels use the same buffer material, their respective optical spacing can be adjusted by using different film thicknesses. For example, the transparent buffer isolation layer 1512 can be made of silicon dioxide, i.e., SiO2, and the thicknesses of the corresponding red, green, and blue sub-pixel electrode regions 123 can be set to 120 nm, 100 nm, and 80 nm, respectively.

[0047] Optionally, a metal reflective layer 16 is provided between the driving backplate 11 and the pixel electrode layer 12.

[0048] Of the light generated by the white light emitting functional layer 13, part of it propagates directly toward the thin film encapsulation layer 14, while the other part propagates toward the driving backplane 11. The metal reflective layer 16 allows a portion of the latter to propagate back toward the thin film encapsulation layer 14, thereby reducing light loss.

[0049] The pixel electrode layer 12 can be made of indium tin oxide (ITO), a transparent conductive electrode, which allows it to retain a certain degree of light transmittance while providing electrical connection. Considering the independent driving requirements of each sub-pixel, the metal reflective layer 16 can be partitioned according to the corresponding area of ​​each sub-pixel, avoiding its connection to electrode areas that would otherwise need to be isolated from each other.

[0050] Optionally, a black matrix is ​​provided between two adjacent composite metasurface units 151, and the projection of the black matrix along the thickness direction of the white light emitting functional layer 13 is located between two adjacent sub-pixel electrode regions.

[0051] The black matrix is ​​a patterned light-blocking area used to block or absorb stray light, and can form strip-shaped or mesh-like boundaries depending on the sub-pixel arrangement. The projection along the thickness direction between adjacent sub-pixel electrode areas means that, when viewed from the light-emitting side of the device, the spacing between the black matrix and the sub-pixel electrode areas corresponds.

[0052] The light generated by the white light emitting functional layer 13 contains a certain proportion of oblique propagation components, and edge scattering may also occur between the nanopillars and the dielectric film layer. If this light enters the composite metasurface unit 151 of an adjacent color, it can easily cause the actual light emission position to be inconsistent with the driven sub-pixel electrode region. The black matrix improves image edge sharpness, color differentiation, and display contrast by blocking stray light that crosses the unit boundary.

[0053] Optionally, please refer to the following: Figure 2 The white light emitting functional layer 13 includes an anode 131, a hole transport layer 132, a white light emitting layer 133, an electron transport layer 134 and a cathode 135 arranged sequentially along the light emission direction, and the pixel electrode layer 12 is electrically connected to the anode 131.

[0054] OLED stands for Organic Light Emitting Diode. Anode 131 and cathode 135 provide electrical interfaces for charge injection, respectively. Hole transport layer 132 and electron transport layer 134 transport holes and electrons to the light-emitting region, causing them to recombine in the white light-emitting layer 133 and generate light. Pixel electrode layer 12 primarily introduces the driving signal from the driving backplane 11 into the corresponding sub-pixel region. Anode 131 forms a hole injection side connection with pixel electrode layer 12. This electrical connection allows the driving signals of different sub-pixels to act on their respective light-emitting regions.

[0055] The white light emitting layer 133 can be formed by combining monochromatic light emitting sub-layers 1331 of different emission bands. For example, a blue light emitting sub-layer can be provided, and combined with red, green and yellow light emitting sub-layers. The required broadband light can be formed by combining the various emission components. A transition layer 1332 can also be provided between these monochromatic light emitting sub-layers 1331 to meet the connection requirements between adjacent film layers.

[0056] The above structure can be implemented as a single-layer WOLED, where "single-layer" refers to a single light-emitting unit 136, not that the entire device consists of only one organic thin film; it can also be implemented as a series-stacked structure, please refer to the reference. Figure 3 For example, two or more light-emitting units 136 can be provided, and a connecting layer 137 can be provided between adjacent light-emitting units 136 to realize the electrical connection between the light-emitting units 136. Regardless of whether a single light-emitting unit 136 or a series stacked light-emitting unit 136 is used, a corresponding pixelated composite metasurface color separation structure can be used on top of it.

[0057] This embodiment also provides a near-eye display device, including a microdisplay 10 as described in any of the above embodiments.

[0058] This near-eye display device includes the same structure and beneficial effects as the microdisplay 10 in the foregoing embodiments. The structure and beneficial effects of the microdisplay 10 have been described in detail in the foregoing embodiments and will not be repeated here.

[0059] The above description is merely an optional embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A microdisplay, characterized in that, It includes a driving backplate, a pixel electrode layer, a white light emitting functional layer, a thin film encapsulation layer, and a color filter layer arranged sequentially along the light emission direction; The pixel electrode layer includes multiple sub-pixel electrode regions, which include red sub-pixel electrode regions, green sub-pixel electrode regions, and blue sub-pixel electrode regions. The color filter layer includes composite metasurface units that correspond one-to-one with each of the sub-pixel electrode regions. Each of the composite metasurface units includes an all-dielectric nanopillar array, a transparent buffer isolation layer, and a distributed Bragg reflection structure arranged sequentially along the light emission direction; the structural parameters of the all-dielectric nanopillar array are different for the sub-pixel electrode regions of different colors, and the film thickness parameters of the distributed Bragg reflection structure are different for the sub-pixel electrode regions of different colors.

2. The microdisplay as described in claim 1, characterized in that, The thickness of the transparent buffer isolation layer corresponding to the sub-pixel electrode regions of different colors is different.

3. The microdisplay as described in claim 1, characterized in that, The all-dielectric nanopillar array comprises multiple periodically arranged all-dielectric nanopillars, the height of which is greater than its lateral dimension.

4. The microdisplay as described in claim 3, characterized in that, The height, lateral dimension, and array period of the all-dielectric nanopillars corresponding to the red sub-pixel electrode region, the green sub-pixel electrode region, and the blue sub-pixel electrode region all decrease sequentially.

5. The microdisplay as described in claim 1, characterized in that, Each of the distributed Bragg reflection structures comprises 4 to 6 pairs of dielectric film layers, each pair of dielectric film layers consisting of an adjacent high-refractive-index dielectric layer and a low-refractive-index dielectric layer.

6. The microdisplay as described in claim 5, characterized in that, In the same distributed Bragg reflection structure, the optical thicknesses of each high-refractive-index dielectric layer and each low-refractive-index dielectric layer satisfy the following: n H d H = n L d L = λ 0 / 4； in, λ 0 represents the design center reflection wavelength of the distributed Bragg reflection structure; n H The refractive index of the high-refractive-index dielectric layer at the wavelength reflected at the design center; n L The refractive index of the low-refractive-index dielectric layer at the wavelength reflected at the design center; d H The optical thickness of the high refractive index dielectric layer; d L The optical thickness of the low-refractive-index dielectric layer is given.

7. The microdisplay as claimed in claim 1, characterized in that, A metal reflective layer is provided between the driving backplate and the pixel electrode layer.

8. The microdisplay as claimed in claim 1, characterized in that, A black matrix is ​​provided between two adjacent composite metasurface units, and the projection of the black matrix along the thickness direction of the white light emitting functional layer is located between two adjacent sub-pixel electrode regions.

9. The microdisplay as claimed in claim 1, characterized in that, The white light emitting functional layer includes an anode, a hole transport layer, a white light emitting layer, an electron transport layer, and a cathode arranged sequentially along the light emission direction, and the pixel electrode layer is electrically connected to the anode.

10. A near-eye display device, characterized in that, Including the microdisplay as described in any one of claims 1 to 9.

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