Display panel, manufacturing method thereof and display device

Abstract

The application provides a display panel and a manufacturing method thereof, and a display device, and belongs to the technical field of display. The display panel comprises a display substrate, an encapsulation cover plate, and a plurality of sub-pixels and light shielding units between the display substrate and the encapsulation cover plate, wherein the plurality of sub-pixels have different light emitting wavelengths; the encapsulation cover plate is provided with an optical adjustment structure on a side close to the display substrate, the optical path of the optical adjustment structure corresponding to sub-pixels with different light emitting wavelengths is different, and the optical path of the optical adjustment structure is positively correlated with the light emitting wavelength corresponding to the sub-pixel. The application can improve the light emitting efficiency of each sub-pixel and effectively inhibit the light leakage between pixels.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a display panel, a method for manufacturing the same, and a display device. Background Technology

[0002] OLED (Organic Light-Emitting Diode) display devices have been listed as a promising next-generation display technology due to their advantages such as being thin, light, having a wide viewing angle, being actively emitting light, having continuously adjustable emission colors, having low cost, fast response speed, low energy consumption, low driving voltage, wide operating temperature range, simple manufacturing process, high luminous efficiency, and being flexible in display.

[0003] In organic light-emitting diode (OLED) display technology, top-emitting structures are widely used due to their high aperture ratio. However, as display products move towards higher pixel densities, existing technologies face two challenges: First, because different color sub-pixels emit different wavelengths, their required microcavity resonant cavity lengths vary, but the planarization layer thickness on traditional packaging covers is usually consistent. This makes it impossible to independently optimize the light-emitting optical path for sub-pixels of different wavelengths, thus limiting the light-emitting efficiency and color purity of each sub-pixel. Second, to ensure the yield of high-pixel-density products, a certain cell thickness is usually required. This causes large-angle emitted light to easily cross the pixel boundary layer and illuminate the light-shielding units of adjacent pixels, resulting in severe inter-pixel light leakage and color gamut attenuation. Summary of the Invention

[0004] This application provides a display panel and its manufacturing method, as well as a display device, which can improve the light emission efficiency of each sub-pixel and effectively suppress light leakage between pixels.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] A display panel includes a display substrate, an encapsulation cover plate, and a plurality of sub-pixels and a light-shielding unit located between the display substrate and the encapsulation cover plate, wherein the plurality of sub-pixels have different emission wavelengths;

[0007] The encapsulation cover plate has an optical adjustment structure on the side near the display substrate. The light-emitting optical path of the optical adjustment structure is different for sub-pixels with different emission wavelengths. The light-emitting optical path of the optical adjustment structure is positively correlated with the emission wavelength of the corresponding sub-pixel.

[0008] In some embodiments, the optical adjustment structure includes a stacked fill layer and a planarization layer, wherein the fill layer is located on the side of the planarization layer closer to the display substrate;

[0009] Provided that the filling layer and the planarization layer materials of each of the sub-pixels are the same, the plurality of sub-pixels include a first sub-pixel, a second sub-pixel, and a third sub-pixel with successively increasing emission wavelengths, and the optical adjustment structure satisfies the following relationship:

[0010] n5*H1+n9*D1<n5*H2+n9*D2<n5*H3+n9*D3;

[0011] Wherein, n5 is the refractive index of the filling layer, and n9 is the refractive index of the planarization layer; H1, H2, and H3 are the heights of the filling layer corresponding to the first sub-pixel, the second sub-pixel, and the third sub-pixel, respectively; and D1, D2, and D3 are the thicknesses of the planarization layer corresponding to the first sub-pixel, the second sub-pixel, and the third sub-pixel, respectively.

[0012] In some embodiments, the encapsulation cover plate is further provided with an optical path deflection structure corresponding to the light-shielding unit on the side near the display substrate;

[0013] The optical path deflection structure is configured to deflect light rays incident on the light-shielding unit to the effective light-emitting area of ​​the sub-pixel.

[0014] In some embodiments, the optical path deflection structure includes a negative refractive material layer.

[0015] In some embodiments, the negative refractive material layer is a metasurface micro / nano structure;

[0016] The metasurface micro / nanostructure includes at least one of a metal-dielectric-metal nanoantenna array or a high-refractive-index dielectric nanopillar array, and the structural size of the metasurface micro / nanostructure is on the subwavelength order.

[0017] In some embodiments, the optical path deflection structure includes a negative refractive material layer and a padding layer, wherein the padding layer is located between the negative refractive material layer and the light-shielding unit;

[0018] The padding layer is configured to increase the distance between the negative refractive material layer and the light-shielding unit, thereby reducing the proportion of light directly hitting the light-shielding unit from a wide viewing angle.

[0019] In some embodiments, the optical path deflection structure is located between the optical adjustment structures of adjacent sub-pixels, and the optical path deflection structure and the optical adjustment structure are flush with or form a stepped undulation on the side surface near the display substrate.

[0020] In some embodiments, the plurality of sub-pixels includes a first sub-pixel, a second sub-pixel, and a third sub-pixel whose emission wavelengths increase sequentially;

[0021] The first sub-pixel, the second sub-pixel, and the third sub-pixel correspond to the blue light sub-pixel, the green light sub-pixel, and the red light sub-pixel, respectively.

[0022] This application also provides a display device, including the display panel described above.

[0023] This application embodiment also provides a method for manufacturing a display panel, used to manufacture the above-mentioned display panel, including forming a display substrate, an encapsulation cover plate, and a plurality of sub-pixels and light-shielding units located between the display substrate and the encapsulation cover plate, wherein the plurality of sub-pixels have different emission wavelengths; the method further includes:

[0024] An optical adjustment structure is formed on the side of the encapsulation cover plate near the display substrate. The light-emitting optical path of the optical adjustment structure is different for sub-pixels with different emission wavelengths. The light-emitting optical path of the optical adjustment structure is positively correlated with the emission wavelength of the corresponding sub-pixel.

[0025] In this embodiment, by setting an optical adjustment structure on the side of the encapsulation cover plate close to the display substrate, and making the light-emitting optical path of the structure positively correlated with the emission wavelength of the corresponding sub-pixel, the matching relationship between the optical path and the wavelength is used to enable long-wavelength sub-pixels to obtain a larger effective optical thickness and short-wavelength sub-pixels to obtain a smaller effective optical thickness. Thus, without changing the overall thickness of the device, independent optimization of the microcavity resonance conditions for different color sub-pixels is achieved, significantly improving the light-emitting efficiency and color purity of each sub-pixel. Attached Figure Description

[0026] Figure 1 and Figure 2 This is a schematic diagram illustrating light leakage in an OLED display device.

[0027] Figure 3 This is a schematic diagram of the structure of a top-emitting OLED device based on related technologies;

[0028] Figure 4 A schematic diagram of the encapsulation cover plate for a top-emitting OLED device based on related technologies;

[0029] Figure 5 This is a schematic diagram showing the relationship between the width of the Bank to the adjacent pixel BM and the light leakage ratio.

[0030] Figures 6-9 This is a schematic diagram of the display panel structure according to an embodiment of this application;

[0031] Figure 10 This is a schematic diagram of the optical path when light travels from a positive refractive index medium into a negative refractive index medium, according to an embodiment of this application.

[0032] Figure Labels

[0033] 1-Display substrate, 2-First electrode, 3-Pixel defining layer, 4-OLED device and encapsulation layer, 5-Matching filling layer, 6-Encapsulation cover plate, 7-Light shielding unit, 8-Color resist unit, 8-1-First sub-pixel color resist unit, 8-2-Second sub-pixel color resist unit, 8-3-Third sub-pixel color resist unit, 9-Planing layer, 10-Negative refractive material layer, 11-Pad layer. Detailed Implementation

[0034] 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, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "a" or "one," and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "connected" or "linked," and similar terms, are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0036] It should be noted that, in the embodiments of the present invention, "same layer" can refer to film layers located on the same structural layer. Alternatively, for example, film layers located on the same layer can be layer structures formed by using the same film deposition process to form a specific pattern, and then patterning the film layer using the same photomask through a single patterning process. Depending on the specific pattern, the single patterning process may include multiple exposure, development, or etching processes, and the specific pattern in the formed layer structure can be continuous or discontinuous. These specific patterns may also be at different heights or have different thicknesses.

[0037] Top-emitting OLED devices can increase aperture ratio because light is emitted from the cathode. The anode of a top-emitting OLED device has high reflectivity, the cathode is a semi-transparent metal, and the cover glass has an array structure formed by a color filter (CF) and a black matrix (BM). In existing top-emitting OLED display devices, the transmittance of the black matrix is ​​essentially zero. When the angle of the emitted light is too large, such as... Figure 1 and Figure 2As shown, the light of the corresponding pixel will irradiate the adjacent pixel, causing light leakage. Figure 1 shows a top-emitting OLED device with a cell thickness of t1, and light leakage occurs when the angle of the outgoing light is greater than θ1; Figure 2 shows a top-emitting OLED device with a cell thickness of t2, and light leakage occurs when the angle of the outgoing light is greater than θ2. When t1<t2, θ1>θ2, that is, the larger the cell thickness, the more likely light leakage is to occur.

[0038] Figure 3 is a schematic structural diagram of a top-emitting OLED device in the related art, Figure 4 is a schematic structural diagram of an encapsulation cover plate of a top-emitting OLED device in the related art, as shown in Figure 3 and Figure 4 , the top-emitting OLED device includes a display substrate 1 containing circuits, a first electrode 2, a pixel defining layer 3, an OLED device and an encapsulation layer 4 disposed on the display substrate 1; and an encapsulation cover plate 6, a filling layer 5, a light-shielding unit 7, a color resist unit 8 and a planarization layer 9 disposed on the encapsulation cover plate 6. The color resist unit 8 includes a first sub-pixel color resist unit 8-1, a second sub-pixel color resist unit 8-2, and a third sub-pixel color resist unit 8-3.

[0039] When the overall cell thickness of the display panel is fixed, in order to reduce light leakage, the prior art mainly adopts a solution of increasing the width from the Bank (pixel defining layer) to the BM (black matrix) of the adjacent pixel. As shown in Figure 5 , the larger the width from the Bank to the BM of the adjacent pixel, the lower the light leakage ratio of the pixel. However, due to the limitations of product resolution and pixel aperture ratio, the width from the Bank to the BM of the adjacent pixel is limited.

[0040] The embodiments of the present application provide a display panel, a manufacturing method thereof, and a display apparatus, which can improve the light extraction efficiency of each sub-pixel and effectively suppress light leakage between pixels.

[0041] As shown in Figures 6-9 , this embodiment provides a display panel. The display panel includes a display substrate 1, an encapsulation cover plate 6, and a plurality of sub-pixels and a light-shielding unit 7 located between the display substrate 1 and the encapsulation cover plate 6. The plurality of sub-pixels have different light emission wavelengths. Specifically, the display substrate 1 usually includes basic structures such as a base substrate and a driving circuit layer, for driving the sub-pixels to emit light. The encapsulation cover plate 6 is located on the light extraction side of the display substrate 1, and functions to protect internal devices and assist light extraction. The light-shielding unit 7 is usually disposed corresponding to the pixel defining region or the non-light-emitting region, for preventing optical crosstalk between adjacent sub-pixels. The plurality of sub-pixels may include, for example, a sub-pixel emitting blue light, a sub-pixel emitting green light, and a sub-pixel emitting red light, with different peak light emission wavelengths.

[0042] In this embodiment, an optical adjustment structure is provided on the side of the encapsulation cover plate 6 near the display substrate 1. The optical path length of the optical adjustment structure corresponding to sub-pixels with different emission wavelengths is different, and the optical path length of the optical adjustment structure is positively correlated with the emission wavelength of the corresponding sub-pixel. Here, the optical adjustment structure refers to a film layer structure disposed on the surface of the encapsulation cover plate 6 facing the display substrate 1, which can adjust the phase or optical path length of the transmitted light. Its specific form is not limited; it can be a single material layer or a composite film layer formed by stacking multiple materials, as long as it can provide differentiated optical thickness for different sub-pixel regions. The optical path length is physically characterized as the sum of the products of the geometric path length of light propagating in the structure and the refractive index of the material. Positive correlation means that for sub-pixels with longer emission wavelengths (e.g., red light sub-pixels), the optical path length provided by the corresponding optical adjustment structure is larger; while for sub-pixels with shorter emission wavelengths (e.g., blue light sub-pixels), the optical path length provided by the corresponding optical adjustment structure is smaller.

[0043] In top-emitting display panels, light resonates in a microcavity between a reflective anode and a semi-transparent cathode. Only light meeting specific resonance conditions can be effectively amplified and emitted. Since different color sub-pixels emit different wavelengths, the total optical thickness of the microcavity required to achieve optimal resonance enhancement also varies significantly. In existing technologies, the film thickness on the encapsulation cover side is usually uniform, making it impossible to simultaneously meet the optimal microcavity conditions for red, green, and blue colors, thus limiting overall light extraction efficiency. This embodiment increases the optical path length of the optical adjustment structure with increasing wavelength, effectively compensating for greater optical thickness for long-wavelength sub-pixels while retaining a thinner optical thickness for short-wavelength sub-pixels. This allows each sub-pixel to independently match its optimal microcavity resonance mode. This not only improves the forward light intensity and color purity of each sub-pixel but also avoids spectral broadening or color shift problems caused by microcavity mismatch.

[0044] In some embodiments, the optical adjustment structure includes a stacked filling layer 5 and a planarization layer 9, wherein the filling layer 5 is located on the side of the planarization layer 9 closest to the display substrate 1. Specifically, as Figure 6 As shown, the filling layer 5 is typically a bonding filler material used to bond the display substrate 1 and the encapsulation cover plate 6, filling the gaps between the OLED device and the encapsulation layer 4 and the planarization layer 9. The planarization layer 9 is disposed on the side of the encapsulation cover plate 6 facing the display substrate 1, covering the color resist unit 8, and serving the dual functions of planarization and optical control. This dual-layer dielectric structure utilizes the difference in refractive index between the two materials, and by adjusting the thickness ratio of the two dielectric layers in each sub-pixel region, the optical path of the emitted light can be controlled.

[0045] Assuming that the filling layer 5 and planarization layer 9 of each sub-pixel are made of the same material, the optical adjustment structure of multiple sub-pixels, including the first sub-pixel, the second sub-pixel, and the third sub-pixel with successively increasing emission wavelengths, satisfies the following relationship:

[0046] n5*H1+n9*D1<n5*H2+n9*D2<n5*H3+n9*D3;

[0047] Where n5 is the refractive index of the filling layer 5, and n9 is the refractive index of the planarization layer 9; H1, H2, and H3 are the heights of the filling layer 5 corresponding to the first, second, and third sub-pixels, respectively; D1, D2, and D3 are the thicknesses of the planarization layer 9 corresponding to the first, second, and third sub-pixels, respectively. It is important to note that the above relationship holds true only if the materials of the filling layer 5 and planarization layer 9 used in each sub-pixel region are consistent, i.e., the refractive indices n5 and n9 are constants across different sub-pixels. In the formula, n5*H and n9*D represent the optical thickness of light propagating in the filling and planarization layers, respectively, and their sum is the total optical path length for that sub-pixel. This inequality mathematically strictly defines the monotonically increasing optical path length as the emission wavelength of the sub-pixel increases.

[0048] Furthermore, the first, second, and third sub-pixels correspond to blue, green, and red light sub-pixels, respectively. In the visible light band, blue light has the shortest peak wavelength (typically in the range of 450nm-470nm), followed by green light (typically in the range of 520nm-540nm), and red light has the longest (typically in the range of 620nm-640nm). Therefore, in this embodiment, the first sub-pixel corresponds to blue light, the second sub-pixel corresponds to green light, and the third sub-pixel corresponds to red light. It should be understood that although this embodiment uses the RGB arrangement order as an example for explanation, the scope of protection of this application is not limited to this specific spatial arrangement order. As long as the logical relationship of "the emission wavelength increases sequentially" is satisfied, the above optical path relationship applies regardless of whether the actual arrangement of the sub-pixels in the display panel is RGB, BGR, or other forms.

[0049] To better understand the above technical solution, a specific parameter configuration example is provided below. Assuming the refractive index n9 of the planarization layer 9 is greater than the refractive index n5 of the filling layer 5 (e.g., n9=1.6, n5=1.5), to satisfy the aforementioned increasing optical path length relationship, the thickness of the planarization layer 9 can be designed to satisfy D1 < D2 < D3. Correspondingly, since the overall cell thickness of the display panel is usually constant, the height of the filling layer 5 exhibits the opposite trend, i.e., H1 > H2 > H3. For example, for blue sub-pixels, the planarization layer thickness D1 can be set to 2μm, and the filling layer height H1 to 8μm; for green sub-pixels, the planarization layer thickness D2 is 3μm, and the filling layer height H2 is 7μm; for red sub-pixels, the planarization layer thickness D3 is 4μm, and the filling layer height H3 is 6μm. Through this differentiated thickness design, although the total geometric thickness of each sub-pixel region remains consistent, the equivalent optical thickness of the red region is significantly greater than that of the blue region because the high refractive index medium (planarization layer 9) accounts for a larger proportion in the red region.

[0050] Conversely, if in some material systems the refractive index n5 of the filling layer 5 is greater than the refractive index n9 of the planarization layer 9, then to achieve the same optical path length increase effect, the thickness relationship will be adjusted to D1 > D2 > D3 and H1 < H2 < H3. This indicates that the specific direction of thickness increase or decrease is not fixed, but depends on the relative magnitude of the refractive indices of the two media, with the core basis always being the positive correlation between the total optical path length and the wavelength.

[0051] In top-emitting OLED devices, light extraction efficiency strongly depends on the microcavity resonance condition, which requires the optical cavity length between the reflective anode and the semi-transparent cathode to be an integer multiple of half the wavelength. Since red light has a longer wavelength, it requires the largest optimal resonance cavity length; while blue light has a shorter wavelength, requiring the smallest cavity length. Existing technologies with uniform planarization layer thickness cannot simultaneously satisfy the optimal resonance conditions for all three colors, often requiring compromises that result in low light extraction efficiency or spectral broadening for some colors. This embodiment utilizes the optical path control formula n5*H+n9*D to maximize the optical cavity length compensation for red sub-pixels while maintaining a smaller optical cavity length for blue sub-pixels, allowing each sub-pixel to operate independently near its microcavity resonance peak. This not only significantly improves the forward light extraction brightness and current efficiency of each sub-pixel but also effectively narrows the emission spectrum, improving the color purity and color gamut coverage of the display panel, thus solving the display performance bottleneck problem caused by microcavity mismatch in high-PPI display products.

[0052] In some embodiments, the encapsulation cover 6 is further provided with a light path deflection structure corresponding to the light-shielding unit 7 on the side near the display substrate 1. The light path deflection structure is configured to deflect the light rays incident on the light-shielding unit 7 to the effective light-emitting area of ​​the sub-pixel. Specifically, as Figures 6-9As shown, the optical path deflection structure includes a negative refractive material layer 10, which is disposed on the side of the encapsulation cover plate 6 facing the display substrate 1. In the direction perpendicular to the display substrate 1, the negative refractive material layer 10 corresponds to the position of the light-shielding unit 7. In a top-emitting display panel, the light emitted from the OLED device and encapsulation layer 4 has a certain divergence angle. Light emitted at large angles often directly illuminates the light-shielding unit 7 between adjacent sub-pixels and is absorbed. This not only wastes light energy but also easily causes crosstalk and light leakage between pixels at large viewing angles. This embodiment utilizes the special optical properties of the negative refractive material layer 10 to change the propagation path of this portion of the light. Figure 10 As shown, when light enters a negative refractive index medium (negative refractive material layer 10) from a positive refractive index medium (such as filling layer 5), the refracted ray and the incident ray will be on the same side of the interface normal, which is the opposite of the conventional positive refraction phenomenon. Negative refraction is a special physical phenomenon in which the incident light and the refracted light are on the same side of the interface normal. Electromagnetic waves undergo refraction at any interface between two materials, and the angle of refraction follows Snell's law (i.e., the law of refraction of light): n1sinθ1=n2sinθ2. n1 and n2 are the refractive indices of the two media (the first medium 1 and the second medium 2), and θ1 and θ2 are the angle of incidence and the angle of refraction, respectively. The refracted light and the incident light are on opposite sides of the normal. Geometric optics follows the law of refraction in optical system design. Assuming n2<0, that is, the refractive index n2 of the second medium 2 is negative, according to the above formula n1sinθ1=n2sinθ2, we know that θ2<0. This means that the refracted light and the incident light are on the same side of the normal, which is different from the conventional refraction phenomenon and is called negative refraction.

[0053] Based on this principle, large-angle light rays originally directed towards the light-shielding unit 7 are reversed after entering the negative refractive material layer 10, thus avoiding the absorption area of ​​the light-shielding unit 7 and being redirected to the color resist unit 8 corresponding to the sub-pixel and the effective light-emitting channel. This design achieves the recycling of ineffective light leakage, significantly improving the overall light emission efficiency and brightness of the display panel without increasing the pixel aperture ratio, while effectively suppressing color shift and light leakage problems at large viewing angles.

[0054] To ensure the effective realization of the negative refractive effect in the visible light band, the negative refractive material layer 10 is a metasurface micro / nanostructure. Since natural materials typically do not possess negative refractive properties in the visible light band, this application constructs an equivalent negative refractive index medium through artificially designed micro / nanostructures. Specifically, the metasurface micro / nanostructure includes at least one of a metal-dielectric-metal nanoantenna array or a high-refractive-index dielectric nanopillar array. For example, in one embodiment, a three-layer nanoantenna array composed of silver-silicon dioxide-silver can be used, utilizing localized surface plasmon coupling resonance between the metal layers to achieve a negative equivalent dielectric constant and permeability; in another embodiment, a nanopillar array made of a high-refractive-index medium such as silicon or titanium dioxide can be used, modulating the electromagnetic wave phase through Mie resonance mode to achieve a broadband negative refractive response. Regardless of the specific form used, the structural dimensions of the metasurface micro / nanostructure must be on the subwavelength order. The subwavelength order here refers to the fact that the unit period, height, and lateral characteristic dimensions of the micro / nanostructure are all smaller than the visible light wavelength, typically in the range of 50 nm to 300 nm. Only when the structure size is much smaller than the working wavelength will the incident light not be diffracted and scattered, but will be regarded as a uniform equivalent medium, thus exhibiting macroscopic negative refractive index characteristics (e.g., refractive index between -2 and -1).

[0055] Furthermore, the optical path deflection structure is located between the optical adjustment structures of adjacent sub-pixels, and the optical path deflection structure and the optical adjustment structure are flush with or form a stepped undulation on the surface near the display substrate 1. For example... Figure 6 and Figure 8 As shown, the negative refractive material layer 10 spatially fills the gap region between the flat layer 9 or the filling layer 5 corresponding to adjacent sub-pixels, that is, it precisely corresponds to the non-light-emitting area below the light-shielding unit 7. This spatial layout ensures that the optical path deflection function only acts on the area where light leakage may occur, without interfering with the microcavity resonance conditions of the normal light-emitting area of ​​the sub-pixel. When the optical path deflection structure and the optical adjustment structure are flush with the surface of the side closest to the display substrate 1, it is beneficial to simplify the packaging assembly process and ensure the uniformity of the cell thickness; while when the two form a stepped undulation, for example, the surface of the negative refractive material layer 10 is slightly lower or higher than the surface of the adjacent optical adjustment structure, the stepped interface can be used to generate additional refraction or total internal reflection guiding effect on the light, further optimizing the light path recovery efficiency. In this embodiment, by spatially coordinating the optical path deflection structure and the optical adjustment structure in the aforementioned embodiment, both microcavity enhancement for positive light emission and negative refractive recovery for lateral light leakage are simultaneously achieved on the same packaging cover plate 6, greatly improving the display performance of the high PPI display panel.

[0056] In some embodiments, to further improve the optical path recovery efficiency under a wide viewing angle, such as Figure 8 and Figure 9As shown, the optical path deflection structure includes a negative refractive material layer 10 and a cushion layer 11, with the cushion layer 11 located between the negative refractive material layer 10 and the light-shielding unit 7. The cushion layer 11 is configured to increase the distance between the negative refractive material layer 10 and the light-shielding unit 7, thereby reducing the proportion of large-angle light directly illuminating the light-shielding unit 7. Specifically, as... Figure 8 As shown, the padding layer 11 is disposed on the side of the encapsulation cover plate 6 facing the display substrate 1, and is precisely located between the negative refractive material layer 10 and the light-shielding unit 7, forming a stacked buffer structure of "negative refractive material layer - padding layer - light-shielding unit". The padding layer 11 should be made of a high-transmittance insulating material, such as transparent organic resin, acrylate photoresist or silicon-based oxide, to ensure that light does not undergo significant absorption loss when passing through the layer.

[0057] If the negative refractive material layer 10 is in direct contact with the light-shielding unit 7, for light rays with extremely large exit angles, the lateral displacement component may be very close to or even overlap with the edge region of the light-shielding unit 7 the instant it enters the negative refractive material layer 10. In this case, even if the negative refraction effect can be activated, the light may be partially absorbed during deflection due to rubbing against the edge of the light-shielding unit 7, resulting in an actual light path recovery efficiency lower than the theoretical value. By adding a padding layer 11 between the two, it is equivalent to providing an additional propagation channel for wide-angle light rays. Although the light follows the conventional positive refraction or rectilinear propagation law when passing through the padding layer 11, this additional vertical distance allows the light ray to have a larger avoidance space relative to the edge of the light-shielding unit 7 when it reaches the working interface of the negative refractive material layer 10. This not only reduces the probability of the light being directly intercepted by the light-shielding unit 7, but also provides a more ample optical working distance for the negative refractive material layer 10 to effectively modulate the phase and deflect the light ray, thereby significantly improving the utilization rate of extremely wide-angle light rays.

[0058] The specific thickness of the padding layer 11 needs to be comprehensively weighed based on the pixel density of the display panel, the cell thickness specifications, and the performance of the negative refractive material layer 10. As a preferred embodiment, the thickness of the padding layer 11 can be set from 0.5 μm to 3 μm. When the thickness is less than 0.5 μm, its contribution to lateral avoidance of light from wide viewing angles is weak, making it difficult to significantly improve light leakage absorption. When the thickness exceeds 3 μm, on the one hand, it may lead to an excessively large overall thickness on the encapsulation cover side, encroaching on the space of the filling layer 5 and thus affecting the control accuracy of the microcavity optical path; on the other hand, it may also introduce unnecessary parasitic reflections or crosstalk. Furthermore, to reduce Fresnel reflections at the film layer interface, the refractive index of the padding layer 11 is preferably matched to the substrate material of the adjacent filling layer 5 or negative refractive material layer 10. For example, when the refractive index of the filling layer 5 is around 1.5, the padding layer 11 can also be made of a transparent resin material with a refractive index in the range of 1.48 to 1.52, thereby achieving a smooth optical transition. Through this structural design, this embodiment effectively solves the problem of light leakage at wide viewing angles while ensuring the negative refraction light path recovery function, further improving the contrast and color gamut performance of the display panel in high brightness and wide viewing angle application scenarios.

[0059] This application also provides a display device, including the above-described display panel.

[0060] As an example, the display device can be a mobile terminal device such as a smartphone, tablet, or laptop. In these devices, users have extremely high requirements for screen brightness, color gamut, and power consumption. Using the display panel provided in this application, the forward light emission efficiency can be improved through precise matching of the microcavity optical path without increasing the battery burden. This results in higher screen brightness under the same driving current, or significantly reduced power consumption while maintaining the same brightness, extending the device's battery life. Simultaneously, the optical path deflection structure effectively suppresses large-angle light leakage, ensuring that users do not experience significant color shift or crosstalk when viewing the screen at tilted angles, thus improving the visual experience of the mobile terminal in various usage postures.

[0061] As another example, the display device can also be a near-eye display system such as a virtual reality (VR) headset, augmented reality (AR) glasses, or mixed reality (MR) device. Such applications require a much higher pixel density (PPI) than traditional display devices, typically reaching thousands of PPI to eliminate the screen-door effect. At such high pixel densities, the pixel pitch is extremely compressed, making the light leakage problem between adjacent pixels in traditional structures particularly critical, severely compromising immersion. The display panel of this application uses a negative refractive material layer to recycle large-angle light rays originally directed towards the light-shielding unit to the effective light-emitting area. This not only fundamentally solves the problem of inter-pixel crosstalk under high PPI but also further improves light energy utilization. This has significant practical value for near-eye display devices that are limited by size and heat dissipation, making it difficult to significantly increase the power of the light source.

[0062] Furthermore, the display device can also be a specialized device with specific requirements for display quality, such as an automotive display, a medical monitor, or a professional monitor. For example, in automotive display scenarios, drivers need to clearly read information in strong light environments and under wide viewing angles. The display panel of this application, with its optimized microcavity resonance resulting in high color purity and its negative refractive structure providing wide viewing angles and low light leakage, can effectively resist ambient light interference and maintain color accuracy, meeting the safety and comfort standards of automotive-grade displays. It should be understood that the application scenarios listed above are merely illustrative and not intended to limit the scope of protection of this application. Any electronic device or display system that includes the aforementioned display panel should be included within the scope of protection of this embodiment.

[0063] This application also provides a method for manufacturing a display panel, used to manufacture a display panel as described in any of the foregoing embodiments. This method constructs a film layer structure with differentiated optical properties on the encapsulation cover side to solve the problems of microcavity mismatch and large-angle light leakage under high pixel density. The manufacturing method first includes forming a display substrate, an encapsulation cover, and multiple sub-pixels and light-shielding units located between the display substrate and the encapsulation cover. The multiple sub-pixels have different emission wavelengths. The manufacturing method also includes conventional processes such as fabricating a driving circuit layer, a pixel defining layer, and an organic light-emitting functional layer on the substrate, and fabricating color resist units and light-shielding units on the encapsulation cover substrate.

[0064] The method further includes: forming an optical adjustment structure on the side of the encapsulation cover plate close to the display substrate, wherein the light-emitting optical path of the optical adjustment structure corresponding to sub-pixels with different emission wavelengths is different, and the light-emitting optical path of the optical adjustment structure is positively correlated with the emission wavelength of the corresponding sub-pixel.

[0065] To achieve this differentiated structure where the emitted optical path varies with wavelength, this embodiment provides a specific process implementation path. As a preferred embodiment, the step of forming the optical adjustment structure can employ a halftone mask process or a grayscale exposure process. Specifically, after coating a layer of photosensitive resin material onto the encapsulation cover as a precursor for the planarization layer, a halftone mask with a gradient transmittance distribution is used for exposure. Because the transmittance varies in different areas of the mask, the photosensitive resin receives different exposure doses in different sub-pixel regions, resulting in a planarization layer 9 with stepped or continuous thickness variations after development. For example, the region corresponding to the blue sub-pixel has the highest exposure dose and the thinnest residual thickness; the region corresponding to the red sub-pixel has the lowest exposure dose and the thickest residual thickness. This single-exposure molding process not only simplifies the process but also precisely controls the thickness ratio of the planarization layer 9 in each sub-pixel region, thereby ensuring that after the filling layer 5 is filled, the emitted optical path of the overall optical adjustment structure strictly satisfies the positive correlation with the emission wavelength. It should be understood that, in addition to halftone masking, multiple coating processes combined with photolithography and etching can also be used to form planar layers 9 with different thicknesses, or optical media of different thicknesses can be directly stacked in a specific area through additive manufacturing processes such as inkjet printing, as long as the final film structure can achieve differentiated optical path configuration.

[0066] Furthermore, if the display panel also includes an optical path deflection structure, a negative refractive material layer 10 needs to be formed in the region corresponding to the light-shielding unit 7 simultaneously or after the formation of the optical adjustment structure. Since the negative refractive material layer 10 is typically a subwavelength-level metasurface micro / nano structure, its fabrication process differs from conventional macroscopic film formation. Specifically, a nanoimprinting process can be used, where a template with a nano-antenna array or nano-pillar array pattern is pre-prepared, and the pattern is transferred to the negative refractive material layer on the encapsulation cover plate via hot pressing or UV curing; or an electron beam lithography process can be used, where a high-energy electron beam directly depicts a high-precision micro / nano pattern on the photoresist, followed by etching or lift-off processes to form the final metasurface structure. These micro / nano fabrication processes can precisely control the period, duty cycle, and height of the structural units, ensuring that the negative refractive material layer 10 exhibits the expected equivalent negative refractive index characteristics in the visible light band. Through the above fabrication methods, the display panel can simultaneously achieve the dual functions of microcavity resonance optimization and large-angle optical path recovery, effectively improving product yield and optical performance consistency.

[0067] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, since the embodiments are basically similar to the product embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the product embodiments.

[0068] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0069] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A display panel, characterized in that, It includes a display substrate, an encapsulation cover plate, and a plurality of sub-pixels and light-shielding units located between the display substrate and the encapsulation cover plate, wherein the plurality of sub-pixels have different emission wavelengths; The encapsulation cover plate has an optical adjustment structure on the side near the display substrate. The light-emitting optical path of the optical adjustment structure is different for sub-pixels with different emission wavelengths. The light-emitting optical path of the optical adjustment structure is positively correlated with the emission wavelength of the corresponding sub-pixel.

2. The display panel according to claim 1, characterized in that, The optical adjustment structure includes a stacked fill layer and a planarization layer, wherein the fill layer is located on the side of the planarization layer closer to the display substrate; Provided that the filling layer and the planarization layer materials of each of the sub-pixels are the same, the plurality of sub-pixels include a first sub-pixel, a second sub-pixel, and a third sub-pixel with successively increasing emission wavelengths, and the optical adjustment structure satisfies the following relationship: n5*H1+n9*D1<n5*H2+n9*D2<n5*H3+n9*D3; Wherein, n5 is the refractive index of the filling layer, and n9 is the refractive index of the planarization layer; H1, H2, and H3 are the heights of the filling layer corresponding to the first sub-pixel, the second sub-pixel, and the third sub-pixel, respectively; and D1, D2, and D3 are the thicknesses of the planarization layer corresponding to the first sub-pixel, the second sub-pixel, and the third sub-pixel, respectively.

3. The display panel according to claim 1, characterized in that, The encapsulation cover plate is also provided with an optical path deflection structure corresponding to the light-shielding unit on the side near the display substrate; The optical path deflection structure is configured to deflect light rays incident on the light-shielding unit to the effective light-emitting area of ​​the sub-pixel.

4. The display panel according to claim 3, characterized in that, The optical path deflection structure includes a negative refractive material layer.

5. The display panel according to claim 4, characterized in that, The negative refractive material layer is a metasurface micro / nano structure; The metasurface micro / nanostructure includes at least one of a metal-dielectric-metal nanoantenna array or a high-refractive-index dielectric nanopillar array, and the structural size of the metasurface micro / nanostructure is on the subwavelength order.

6. The display panel according to claim 4, characterized in that, The optical path deflection structure includes a negative refractive material layer and a padding layer, wherein the padding layer is located between the negative refractive material layer and the light-shielding unit; The padding layer is configured to increase the distance between the negative refractive material layer and the light-shielding unit, thereby reducing the proportion of light directly hitting the light-shielding unit from a wide viewing angle.

7. The display panel according to claim 4, characterized in that, The optical path deflection structure is located between the optical adjustment structures of adjacent sub-pixels, and the optical path deflection structure and the optical adjustment structure are flush with or form a stepped undulation on the side surface near the display substrate.

8. The display panel according to claim 1, characterized in that, The plurality of sub-pixels includes a first sub-pixel, a second sub-pixel, and a third sub-pixel whose emission wavelengths increase sequentially; The first sub-pixel, the second sub-pixel, and the third sub-pixel correspond to the blue light sub-pixel, the green light sub-pixel, and the red light sub-pixel, respectively.

9. A display device, characterized in that, Includes the display panel as described in any one of claims 1 to 8.

10. A method for manufacturing a display panel, characterized in that, For manufacturing a display panel as described in any one of claims 1 to 8, the panel includes forming a display substrate, an encapsulation cover, and a plurality of sub-pixels and a light-shielding unit located between the display substrate and the encapsulation cover, wherein the plurality of sub-pixels have different emission wavelengths; The method further includes: An optical adjustment structure is formed on the side of the encapsulation cover plate near the display substrate. The light-emitting optical path of the optical adjustment structure is different for sub-pixels with different emission wavelengths. The light-emitting optical path of the optical adjustment structure is positively correlated with the emission wavelength of the corresponding sub-pixel.

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