Display substrate, manufacturing method thereof and display device

Abstract

The application provides a display substrate, a manufacturing method thereof and a display device. The display substrate comprises a substrate, a plurality of sub-pixels formed on the substrate and arranged periodically, and a diffraction grating formed on the substrate and configured to compress +1 order diffraction angles of light beams of different colors to the same angle. In the embodiment of the application, the diffraction grating is arranged, so that the +1 order diffraction light beams of different colors coincide in space, thereby mixing to form a white light halo, and effectively eliminating the color separation phenomenon caused by the separation of diffraction light beams of different colors in the traditional periodic pixel structure.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a display substrate, a method for manufacturing the same, and a display device. Background Technology

[0002] With the development of display technology, users' requirements for screen display quality are increasing. In existing display substrates, subpixels are usually arranged periodically, and their openings will produce a diffraction effect on the illumination light. When ambient light shines on the screen, the diffracted light from different color subpixels interferes with each other, easily producing obvious color separation and affecting the visual effect. Summary of the Invention

[0003] This invention provides a display substrate and its manufacturing method, as well as a display device, to solve the problem that ambient light irradiation on the screen easily causes obvious color separation, affecting the visual effect.

[0004] To solve the above problems, the present invention is implemented as follows: In a first aspect, embodiments of the present invention provide a display substrate, comprising: Substrate; Multiple sub-pixels are formed on the substrate, and the multiple sub-pixels are arranged periodically; A diffraction grating is formed on the substrate, and the diffraction grating is configured to compress the +1st order diffraction angle of different colors of light to the same angle.

[0005] In some embodiments, the diffraction grating includes: The first grating layer is configured to enable the first color light to produce +1 order diffraction. The second grating layer is configured to enable the second color light and the third color light to produce +1st order diffraction, wherein the +1st order diffraction angle of the first color light is equal to the +1st order diffraction angle of the second color light and the third color light. A planarization layer is formed between the first grating layer and the second grating layer. The refractive index and thickness of the planarization layer are configured to satisfy a preset optical path difference condition so that the first color light, the second color light and the third color light are superimposed in phase at the exit surface.

[0006] In some embodiments, the first grating layer includes a first blazed grating configured to concentrate the diffraction energy of the first color light at the +1st diffraction order.

[0007] In some embodiments, the period of the first grating layer is 1.5µm to 2.5µm, and the blaze angle is 12° to 15°.

[0008] In some embodiments, the second grating layer includes a second blazed grating configured to concentrate the diffraction energy of the second and third color light at the +1st diffraction order.

[0009] In some embodiments, the period of the second blazed grating is 2.2µm to 3.4µm, and the reverse blaze angle is 10° to 13°.

[0010] In some embodiments, the planarization layer has a refractive index of 1.40 and a thickness of 500 nm.

[0011] In some embodiments, the diffraction grating includes a plurality of sub-gratings that are not equally spaced.

[0012] In some embodiments, the display substrate further includes: A black matrix layer, comprising multiple black matrix patterns arranged periodically, wherein the arrangement period of the black matrix patterns is an integer multiple of the period of the diffraction grating; A reflective pattern is located at the center of each of the black matrix patterns. The thickness of the reflective pattern is set such that the phase difference between the zero-order light reflected by the reflective pattern and the zero-order light reflected by the sub-pixel opening region is π.

[0013] In some embodiments, the peak wavelength of the first color light is 430 nm to 470 nm, the peak wavelength of the second color light is 520 nm to 550 nm, and the peak wavelength of the third color light is 610 nm to 650 nm.

[0014] Secondly, embodiments of this application provide a display device including the display substrate described in any one of the first aspects.

[0015] Thirdly, embodiments of this application provide a method for manufacturing a display substrate, comprising the following steps: Provide a substrate; A driving circuit layer is fabricated on the substrate, the driving circuit layer including a plurality of sub-pixels, the plurality of sub-pixels being periodically arranged; A diffraction grating is fabricated on the driving circuit layer, and the diffraction grating is configured to compress the +1 order diffraction angles of different color light emitted by the plurality of sub-pixels to the same angle.

[0016] In this embodiment, by setting a diffraction grating, the +1st order diffracted light of different colors can be made to overlap in space, thereby mixing to form a white halo. This effectively eliminates the color separation phenomenon caused by the separation of diffracted light of different colors in traditional periodic pixel structures. At the same time, by transferring energy from the 0th order and concentrating it to the +1st order, specular reflection can be suppressed, glare under ambient light can be reduced, and contrast can be improved. This solution does not destroy the original periodic arrangement of subpixels and does not require a reduction in aperture ratio, thus maintaining the advantages of high transmittance and low power consumption. It is also compatible with existing evaporation and photolithography processes and has good mass production feasibility. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1A This is one of the schematic diagrams illustrating the color separation phenomenon in display panels in related technologies; Figure 1B This is the second schematic diagram of color separation phenomenon in display panels in related technologies; Figure 2A This is one of the schematic diagrams showing the arrangement of sub-pixels in the embodiments of this application; Figure 2B This is the second schematic diagram of the sub-pixel arrangement in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the display substrate provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the black matrix layer and the reflection pattern in the embodiments of this application; Figure 5A This is one of the schematic diagrams illustrating the elimination of color separation in the display panel in the embodiments of this application; Figure 5B This is the second schematic diagram of the display panel eliminating color separation in the embodiments of this application; Figure 6 This is a schematic diagram of the manufacturing process of the display substrate in an embodiment of this application. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the embodiments of this invention, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices. Additionally, the use of "and / or" in this application indicates at least one of the connected objects, such as A and / or B and / or C, representing seven possibilities: including A alone, B alone, C alone, and the presence of both A and B, both B and C, both A and C, and the presence of A, B, and C.

[0021] like Figure 1A and Figure 1B As shown, when the display panel is in the off state and is illuminated by an external light source, especially an external point light source, the diffracted light from the opening area of ​​a single pixel will produce a significant color separation phenomenon due to the periodic interference and superposition of the geometrical sizes of the sub-pixels of different colors.

[0022] This application provides a display substrate.

[0023] As shown in FIG2, the display substrate provided in this application embodiment includes a substrate 101, and a plurality of sub-pixels and a diffraction grating formed on the substrate 101.

[0024] The technical solution of this embodiment is mainly applied to COE (Color Filter on Encapsulation) display devices, specifically, to OLED (Organic Light-Emitting Diode) display substrates using COE technology. It directly integrates a color filter and a black matrix above the thin-film encapsulation layer (TFE) 103 to replace the traditional polarizer, thereby significantly reducing ambient light reflection. Compared to traditional screens, COE can reduce the module thickness by approximately 20% and increase optical transmittance by more than 50%. Therefore, it can achieve higher brightness with the same power consumption, or reduce power consumption by 20% to 30% with the same brightness. It also improves bending reliability and has been widely used in foldable phones and silicon-based OLED microdisplays.

[0025] As shown in Figure 2, a driving circuit layer and light-emitting units 102 of different colors are fabricated on the substrate 101 of this embodiment. Figure 2 exemplarily shows three colors of light-emitting units 102: red (R), green (G), and blue (B). The driving circuit layer typically includes one or more stacked semiconductor layers, conductive layers, insulating layers, etc., and is used to form a driving circuit for driving the light-emitting units 102 to emit light. In this embodiment, the specific structure of the driving circuit is not further limited or described. A thin film encapsulation layer 103 is typically disposed on the side of the light-emitting unit 102 away from the substrate 101.

[0026] Multiple subpixels are arranged periodically. More specifically, it can be understood as the periodic arrangement of light-emitting units 102 of each subpixel. A subpixel is the smallest independent controllable light-emitting unit 102 on the display substrate. For color displays, each pixel is usually composed of three subpixels: red, green, and blue (RGB). Sometimes, a white subpixel (RGBW) is added to increase brightness.

[0027] like Figure 2A and Figure 2B As shown, the shape of each sub-pixel can be set to different shapes such as circle, ellipse, inverted ellipse, rectangle, etc., as needed.

[0028] Periodic arrangement refers to the repeated arrangement of subpixels on the substrate plane according to a fixed spatial period. Common arrangement methods include strip arrangement, Delta arrangement, etc.

[0029] A diffraction grating is formed on the substrate 101. In this embodiment, specifically on the side of the thin film encapsulation layer 103 away from the substrate 101, the diffraction grating is configured to compress the +1 order diffraction angle of different colors of light to the same angle.

[0030] Related technologies typically employ sub-pixel openings of different sizes, spacings, or shapes and alter their arrangement direction. This can be summarized as disrupting the periodicity of the pixel array to suppress interference conditions. However, this approach may adversely affect the display effect.

[0031] In the technical solution of this embodiment, by designing the structural parameters of the diffraction grating, the +1st order diffracted light of different wavelengths has the same diffraction angle.

[0032] Generally speaking, white light sources can be divided into three primary colors: red, green, and blue. Therefore, in some exemplary embodiments, different colors of light refer to the three colors of red, green, and blue.

[0033] In some embodiments, the peak wavelength of the first color light is 430 nm to 470 nm, the peak wavelength of the second color light is 520 nm to 550 nm, and the peak wavelength of the third color light is 610 nm to 650 nm.

[0034] Generally, the peak wavelength of blue light (the primary color) is 450 nm, the peak wavelength of green light (the secondary color) is 530 nm, and the peak wavelength of red light (the tertiary color) is 620 nm. These three wavelengths correspond to the typical peak values ​​of the three primary colors of blue, green, and red in the standard RGB color system, respectively.

[0035] It should be noted that the emission spectrum of the display panel has a certain full width at half maximum (FWHM), for example, blue may be 30 nm, green 40 nm, and red 50 nm. In this embodiment, the diffraction grating is designed with bandwidth considerations to a certain extent, that is, the variation of the +1 order diffraction angle is required to be as small as possible across the entire spectrum to avoid color separation.

[0036] By ensuring that the +1st order diffracted light of different wavelengths has the exact same diffraction angle, the red, green, and blue light can overlap when observing the display panel to form a white or correct color image, thereby reducing the impact on the visual effect and display performance of the display panel.

[0037] In some embodiments, the diffraction grating includes a first grating layer 105, a planarization layer 106, and a second grating layer 107 stacked sequentially.

[0038] The first grating layer 105 is configured to enable the first color light to produce +1st order diffraction, and the first grating layer 105 is configured to enable the second color light and the third color light to produce +1st order diffraction, wherein the +1st order diffraction angle of the first color light is equal to the +1st order diffraction angle of the second color light and the third color light.

[0039] A planarization layer 106 is formed between the first grating layer 105 and the second grating layer 107. The refractive index and thickness of the planarization layer 106 are configured to meet a preset optical path difference condition so that the first color light, the second color light and the third color light are superimposed in phase at the exit surface.

[0040] In this embodiment, the first grating layer 105 is optimized for the first color light, such as blue light with the shortest wavelength, to maximize its +1st order diffraction efficiency, and its diffraction angle is set as the target angle.

[0041] The second grating layer 107 optimizes both the second color light (green light) and the third color light (red light) simultaneously. By appropriately selecting the period and blaze angle, both green light and red light produce +1 order diffraction, and their diffraction angles are exactly equal to the aforementioned target angles.

[0042] It should be noted that, since green light and red light have different wavelengths, in order to achieve the same diffraction angle, the period of the second grating layer 107 needs to satisfy a specific dispersion relation, and the period is usually larger than that of the first grating layer 105.

[0043] The planarization layer 106 is located between the two grating layers. Its main optical function is to control the refractive index n and thickness h of the planarization layer 106 so that the blue light emitted from the first grating layer 105 and the red and green light emitted from the second grating layer 107 are in phase on the final emission surface.

[0044] This is because light waves accumulate different phase delays after passing through different paths (different layers). By setting the refractive index n of the flat layer to 106 and the thickness h, the additional optical path difference of blue light relative to red and green light can be made to be exactly an integer multiple of λ, thereby achieving coherent superposition rather than destructive interference.

[0045] On the side of the second grating layer 107 away from the substrate, a first protective layer 108 is further fabricated to protect the diffraction grating.

[0046] On the side of the diffraction grating away from the substrate 101, it is typically necessary to fabricate a color filter (CF) 109, a black matrix layer 110, a second protective layer 108, an optical adhesive layer OCA 113, and to provide an encapsulation cover plate 114.

[0047] In some embodiments, the first grating layer 105 includes a first blazed grating configured to concentrate the diffraction energy of the first color light at the +1st diffraction order.

[0048] A blazed grating is a special type of reflective or transmissive grating, typically with sawtooth-shaped grooves. It achieves high efficiency by concentrating most of the light energy into a specific diffraction order. Unlike ordinary planar gratings where energy is dispersed across multiple orders (0th, ±1st, ±2nd, etc.), where the 0th order has no dispersion and higher orders have very low energy, a blazed grating precisely controls the blaze angle (the angle between the sawtooth bevel and the grating plane) so that the reflection direction of the bevel aligns perfectly with the direction of the target diffraction order, thus transferring energy from the 0th order to that order.

[0049] In this embodiment, the first blazed grating is designed for the first color light (e.g., blue light, wavelength 450 nm), making its +1st order diffraction efficiency exceed 80%, even reaching over 90%, while the energy of the 0th and -1st orders is suppressed to a very low level. This ensures that after passing through the diffraction grating, the vast majority of the blue light is emitted along the direction of the preset target angle, reducing stray light and light loss.

[0050] Blazed gratings can be fabricated using methods such as electron beam lithography, nanoimprint lithography, or reactive ion etching to form a serrated profile on glass, polymer, or metal thin films. For blue light, due to its short wavelength, the period and blaze angle of the blazed grating need to be very precise, typically with a period of 1 to 3 µm and a blaze angle between 10° and 20°.

[0051] In some embodiments, the period P1 of the first grating layer 105 is 1.5µm to 2.5µm. For example, different values ​​such as 1.5µm, 1.6µm, 1.7µm, 1.8µm, 1.9µm, 2.0µm, 2.1µm, 2.2µm, 2.3µm, 2.4µm, and 2.5µm can be selected. The blaze angle γ1 is 12° to 15°. For example, different values ​​such as 12°, 12.5°, 13°, 13.5°, 14°, and 15° can be selected.

[0052] The period P1 of the first grating layer 105 is set to 1.5µm to 2.5µm, which is easy to process and is much larger than the blue light wavelength, thus avoiding the resonant domain anomalous effect.

[0053] To verify the effectiveness of this parameter for the first color light (assuming λ1 = 450 nm), its +1st order diffraction angle is first calculated.

[0054] Assuming the light rays are incident perpendicularly, the equation of the grating is: P1·sinθ1 = λ; For example, substituting P1=2.0µm=2000 nm and λ=450 nm, we get sinθ1= 450 / 2000 = 0.225, so θ1 ≈ 13.0°.

[0055] When the "Littrow condition" (i.e., the incident angle equals the diffraction angle, and both are equal to the blaze angle) is met, the diffraction efficiency of that wavelength reaches the theoretical peak. That is, when the blaze angle γ1 is 13°, the diffraction efficiency of that wavelength reaches the theoretical peak. By controlling the blaze angle γ1 between 12° and 15°, it is possible to obtain a +1st order diffraction efficiency of over 85% at 450 nm.

[0056] The duty cycle of the first blazed grating can be set to 35% to 45%, for example, different values ​​such as 35%, 35%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, etc., which can balance the light transmittance and the diffraction effect of light.

[0057] In practice, the tilted first blazed grating can be fabricated using processes such as quartz nanoimprinting.

[0058] In some embodiments, the second grating layer 107 includes a second blazed grating configured to concentrate the diffraction energy of the second and third color light into the +1st diffraction order.

[0059] The second blazed grating needs to process two wavelengths of light simultaneously, namely green light and red light. By reasonably selecting the period, blaze angle and grating material, it is possible to keep the diffraction efficiency of both at a high level, provided that the +1 order diffraction angles of green light and red light are equal.

[0060] Since the wavelengths of red and green light are longer than those of blue light, the period of the second blazed grating is longer than that of the first blazed grating, which enables red and green light to produce a +1 order diffraction angle that is closer to that of blue light.

[0061] In some embodiments, the period P2 of the second blazed grating is from 2.2µm to 3.4µm; for example, different values ​​such as 2.2µm, 2.3µm, 2.4µm, 2.5µm, 2.6µm, 2.8µm, 3.0µm, 3.1µm, 3.2µm, 3.3µm, and 3.4µm can be selected. The reverse blaze angle γ2 is from 10° to 13°; for example, different values ​​such as 10°, 10.5°, 11°, 11.5°, 12.5°, and 13° can be selected.

[0062] This embodiment uses a reverse blaze angle, that is, the tilt direction of the sawtooth groove of the second blaze grating is opposite to that of the first grating layer 105. This can make the +1st order diffraction direction of red and green light deflect to the other side, but ultimately, through the planarization layer 106 and the overall structural design, they are made to be consistent with the +1st order direction of blue light.

[0063] Since a longer wavelength results in a larger diffraction angle for the same period, the second blazed grating has a larger period to reduce the diffraction angle of red light.

[0064] To accommodate both green (530nm) and red (620nm) light, the second blazed grating period needs to be chosen between the two, such that sinθ = λ / P², calculated separately for green and red light, results in an acceptable difference. While the slot shape of the blazed grating can be symmetrical (e.g., rectangular), its efficiency is low; therefore, a sawtooth shape is still used.

[0065] An example is given with a period P2 = 2.8µm and a reverse blaze angle γ2 = 11°. "Reverse" means the tilt direction of the blaze angle is opposite to that of the first grating layer 105. For example, if the sawtooth bevel of the first blaze grating faces to the right, then the sawtooth bevel of the second blaze grating faces to the left. This allows the +1st order diffracted light from both gratings to be deflected towards the center, and ultimately converged to the same emission direction through refraction and phase matching by the planarization layer 106.

[0066] For green light (530nm), sinθ2 = 530 / 2800 ≈ 0.1893, θ2 ≈ 10.9°; for red light (620nm), sinθ3 = 620 / 2800 ≈ 0.2214, θ3 ≈ 12.8°. Therefore, the reverse blaze angle of the second blaze grating should be between 10.9° and 12.8°. Further considering the potential fluctuations in the peak values ​​of green and red light, the reverse blaze angle range is set between 10° and 13°.

[0067] The duty cycle of the second blazed grating can be set to 45% to 55%, for example, different values ​​such as 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, etc., which can balance the light transmittance and the diffraction effect of light.

[0068] In this embodiment, the second grating layer 107 can be made of a material with a high refractive index. For example, in this embodiment, the refractive index of the second grating layer 107 is selected as n1=1.78, and the transmission grating is made by UV (ultraviolet) curing resin process.

[0069] In some embodiments, the planarization layer 106 has a refractive index n2 of 1.40 and a thickness h of 500 nm.

[0070] The planarization layer 106 plays two key roles between the two grating layers: first, it provides a flat surface for fabricating the second grating layer 107 on top; second, it serves as an optical phase adjustment layer.

[0071] To ensure that the blue light is in phase with the red and green light at the final exit surface, the phase difference Δφ(λ) must satisfy: Δφ(λ)=2π·h·(n1–n2) / λ; Where λ is the wavelength of light, by selecting a suitable refractive index n2 and thickness h of the planarization layer 106, the phase difference caused by the grating structure for different wavelengths can be compensated.

[0072] In some embodiments, the diffraction grating includes a plurality of sub-gratings that are not equally spaced.

[0073] A sub-grating refers to dividing the entire diffraction grating region into multiple small blocks (sub-regions). These sub-gratings are distributed non-equidistantly. For example, the grating is divided into 200 nm × 200 nm segments as a sub-grating. A ±50 nm lateral random displacement is applied to each sub-grating, causing them to be non-equidistantly distributed in their alignment direction. This random displacement introduces phase noise. The different displacements of each sub-grating cause random variations in the optical path difference, thus disrupting the coherent superposition of higher-order diffraction. However, the zeroth-order diffraction remains unaffected because all segments contribute in phase. This is equivalent to adding controlled scattering to the grating, dispersing higher-order energy over a larger angle, thereby reducing the intensity in a specific direction. This structure does not disrupt zero-order transmission but scatters higher-order diffraction energy to 30°.

[0074] like Figure 4 As shown, in some embodiments, the display substrate further includes a black matrix layer 110, which includes a plurality of black matrix patterns arranged periodically, the arrangement period of which is an integer multiple of the period of the diffraction grating.

[0075] The reflective pattern 111 is located at the center of each black matrix pattern. The thickness of the reflective pattern 111 is set such that the phase difference between the 0th order light reflected by the reflective pattern 111 and the 0th order light reflected by the sub-pixel opening area is π.

[0076] Black matrices (BMs) are typically used to separate different sub-pixels, prevent color crosstalk, and reduce ambient light reflection. In this embodiment, an additional reflective pattern 111 is provided at the center of the black matrix pattern (i.e., the center of each black matrix strip). This reflective pattern 111 can be a metal (aluminum, silver) or a high-refractive-index dielectric layer. Its thickness causes a π-phase difference (i.e., half-wavelength optical path difference) to be generated between the zero-order light reflected from this reflective pattern 111 (i.e., ambient light incident perpendicularly and reflected perpendicularly back) and the zero-order light reflected from the sub-pixel opening area (the area not covered by the black matrix).

[0077] According to the principle of interference, when two reflected light beams have similar amplitudes and opposite phases, they will cancel each other out, thus significantly reducing the overall reflectivity and improving display contrast. For example, if the thickness of the reflective pattern 111 is chosen to be λ / 4n (λ is the center wavelength, and n is the refractive index of the medium), then the phase delay of the reflected light is π. Simultaneously, the reflective pattern 111 should not affect the light extraction efficiency of the sub-pixels. This design works in conjunction with the diffraction grating; the diffraction grating controls the +1st order direction of the emitted light, while the reflective pattern 111 on the black matrix eliminates 0th order ambient light reflection, both contributing to improved display quality.

[0078] The period of the black matrix pattern is an integer multiple of the period of the diffraction grating. For example, if the period P1 of the first diffraction grating is 2nm, then the period of the black matrix pattern can be set to twice P1, i.e., 4nm.

[0079] This integer multiple relationship ensures that the diffraction interference effects generated by the black matrix and the grating are constructive or destructive, avoiding the generation of low-frequency moiré patterns. The 0th order of the reflection pattern 111 is spatially in phase with the 0th order of the pixel aperture reflection, but in opposite phases. Therefore, the two beams interfere destructively in the far field, and the 0th order energy decreases by about 20%. The distance between the grating of the pixel aperture and the Ag point in the BM region is the thickness of the CF (color filter 109), typically 2–3 µm, which is much smaller than the visible light coherence length (tens of µm).

[0080] The thickness of the reflective pattern 111 should be set according to its material. Taking silver (Ag) as an example, the refractive index of silver nAg≈0.12+i4.8 and the reflection phase≈π, the thickness of the reflective pattern 111 is about 120 nm.

[0081] The reflective pattern 111 in the non-pixel area does not directly modify the grating within the pixel, but acts as a "distributed reflector" to cancel out the 0th order light interference of the pixel reflection in the far field, thereby reducing the specular reflection of the entire panel.

[0082] like Figure 5A and Figure 5B As shown, the technical solution adopted in this embodiment can effectively reduce the color classification phenomenon of the display panel.

[0083] This application also provides a display device, including the display substrate of any of the above.

[0084] Since the technical solution of this embodiment includes all the technical solutions of the above-described display substrate embodiments, it can achieve at least all of the above-described technical effects, which will not be repeated here.

[0085] This application provides a method for manufacturing a display substrate.

[0086] like Figure 6 As shown, in one embodiment, the method includes the following steps: Step 601: Provide a substrate; Step 602: Fabricate a driving circuit layer on the substrate, the driving circuit layer including a plurality of sub-pixels, the plurality of sub-pixels being periodically arranged; Step 603: Fabricate a diffraction grating on the driving circuit layer, the diffraction grating being configured to compress the +1 order diffraction angles of different color light emitted by the plurality of sub-pixels to the same angle.

[0087] In some embodiments, the step of fabricating a diffraction grating on the driving circuit layer includes: A first grating layer is fabricated, and the first grating layer is configured to cause the first color light to produce +1 order diffraction; A planarization layer is fabricated on the first grating layer. The refractive index and thickness of the planarization layer are configured to satisfy a preset optical path difference condition so that the first color light, the second color light and the third color light are superimposed in phase at the exit surface. A second grating layer is fabricated on the planarization layer. The second grating layer is configured to enable the second color light and the third color light to produce +1st order diffraction, wherein the +1st order diffraction angle of the first color light is equal to the +1st order diffraction angle of the second color light and the third color light.

[0088] In some embodiments, after the diffraction grating is fabricated on the driving circuit layer, the following is also included: The grating is divided into multiple sub-gratings, and some or all of the sub-gratings are displaced so that the sub-gratings are not evenly spaced.

[0089] In some embodiments, after the diffraction grating is fabricated on the driving circuit layer, the method further includes: A reflective pattern is created, the thickness of which is set such that the phase difference between the 0th order light reflected by the reflective pattern and the 0th order light reflected by the sub-pixel opening region is π. A black matrix layer is fabricated, comprising multiple black matrix patterns, with the reflective pattern located at the center of the black matrix patterns. The black matrix patterns are arranged periodically, and the arrangement period of the black matrix patterns is an integer multiple of the period of the diffraction grating.

[0090] The structures fabricated in the above steps can be referred to the above-described display substrate embodiment, and will not be repeated here.

[0091] The technical solution of this embodiment can be summarized as follows: First, referring to relevant technologies, the driving circuit layer, light-emitting unit 102, and thin-film encapsulation layer 103 of the display substrate are fabricated on the substrate 101. Next, a diffraction grating is fabricated. Specifically, a first grating layer 105 is fabricated by nanoimprinting a quartz master mold tilted blazed grating onto a glass substrate. Then, a planarization layer 106 is fabricated. Next, an upper resin grating, namely the second grating layer 107, is fabricated through a single exposure using a UV curing process.

[0092] The next step is to fabricate the first protective layer 108. After the first protective layer 108 is fabricated, the color film CF109 is fabricated according to conventional processes, and the reflective pattern 111 is deposited by vapor deposition. Then, photolithography and dry etching are performed to form the black matrix pattern.

[0093] The parameters of each structure produced can be referred to in the above-described display substrate embodiment, and will not be repeated here.

[0094] After fabricating the black matrix, a second protective layer 112 can be further fabricated. For example, a 30nm thick silicon dioxide layer can be deposited as the second protective layer 11. Finally, the subsequent optical adhesive layer OCA 113 and the encapsulation cover plate 114 are fabricated using conventional processes in related technologies, which are not further limited or described here.

[0095] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A display substrate, characterized in that, include: Substrate; Multiple sub-pixels are formed on the substrate, and the multiple sub-pixels are arranged periodically; A diffraction grating is formed on the substrate, and the diffraction grating is configured to compress the +1st order diffraction angle of different colors of light to the same angle.

2. The display substrate according to claim 1, characterized in that, The diffraction grating includes: The first grating layer is configured to enable the first color light to produce +1 order diffraction. The second grating layer is configured to enable the second color light and the third color light to produce +1st order diffraction, wherein the +1st order diffraction angle of the first color light is equal to the +1st order diffraction angle of the second color light and the third color light. A planarization layer is formed between the first grating layer and the second grating layer. The refractive index and thickness of the planarization layer are configured to satisfy a preset optical path difference condition so that the first color light, the second color light and the third color light are superimposed in phase at the exit surface.

3. The display substrate according to claim 2, characterized in that, The first grating layer includes a first blazed grating, which is configured to concentrate the diffraction energy of the first color light into the +1st diffraction order.

4. The display substrate according to claim 3, characterized in that, The period of the first grating layer is 1.5µm to 2.5µm, and the blaze angle is 12° to 15°.

5. The display substrate according to claim 2, characterized in that, The second grating layer includes a second blazed grating configured to concentrate the diffraction energy of the second color light and the third color light into the +1st diffraction order.

6. The display substrate according to claim 5, characterized in that, The period of the second blazed grating is 2.2µm to 3.4µm, and the reverse blaze angle is 10° to 13°.

7. The display substrate according to claim 2, characterized in that, The planarization layer has a refractive index of 1.40 and a thickness of 500 nm.

8. The display substrate according to claim 1, characterized in that, The diffraction grating includes multiple sub-gratings, which are distributed at non-equidistant intervals.

9. The display substrate according to claim 1, characterized in that, The display substrate further includes: A black matrix layer, comprising multiple black matrix patterns arranged periodically, wherein the arrangement period of the black matrix patterns is an integer multiple of the period of the diffraction grating; A reflective pattern is located at the center of each of the black matrix patterns. The thickness of the reflective pattern is set such that the phase difference between the zero-order light reflected by the reflective pattern and the zero-order light reflected by the sub-pixel opening region is π.

10. The display substrate according to any one of claims 2 to 9, characterized in that, The peak wavelength of the first color light is 430nm to 470nm, the peak wavelength of the second color light is 520nm to 550nm, and the peak wavelength of the third color light is 610nm to 650nm.

11. A display device, characterized in that, The display substrate includes any one of claims 1 to 10.

12. A method for manufacturing a display substrate, characterized in that, Includes the following steps: Provide a substrate; A driving circuit layer is fabricated on the substrate, the driving circuit layer including a plurality of sub-pixels, the plurality of sub-pixels being periodically arranged; A diffraction grating is fabricated on the driving circuit layer, and the diffraction grating is configured to compress the +1 order diffraction angles of different color light emitted by the plurality of sub-pixels to the same angle.

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