Display panel and display device

Abstract

The invention relates to the technical field of micro display, and discloses a display panel and a display device.The display panel comprises light-emitting units arranged in an array, and each light-emitting unit comprises light-emitting areas of different colors and pixel definition structures arranged between the adjacent light-emitting areas; the first anti-reflection layer is arranged on one side, far away from the substrate, of the pixel definition structure; the lens layer is arranged on the side, away from the substrate, of the light-emitting unit, and the lens layer comprises micro lens structures in one-to-one correspondence with the light-emitting areas; and the second anti-reflection layer is arranged between any two adjacent micro lens structures. According to the invention, the first anti-reflection layer, the second anti-reflection layer and the third anti-reflection layer form a multi-stage anti-reflection path which works cooperatively, so that environmental stray light which enters from different angles can be absorbed and reduced layer by layer.

Description

Technical Field

[0001] This invention belongs to the field of micro-display technology, specifically relating to a display panel and display device, and more particularly to a silicon-based OLED display panel and display device with an optical anti-reflection structure. Background Technology

[0002] With the rapid development of near-eye display devices such as augmented reality (AR) and virtual reality (VR), extremely high performance requirements have been placed on microdisplay panels, especially silicon-based organic light-emitting diode (Micro OLED) microdisplays, which are the core imaging elements. These displays not only need to have high brightness, high contrast, and high resolution, but also excellent anti-reflection capabilities under strong ambient stray light (AR) or stray light reflected back from the internal optical engine (VR) conditions, in order to avoid external stray light forming "ghosting" or virtual images in the optical system, which would seriously affect the user experience.

[0003] Traditional solutions involve attaching additional anti-reflective glass to the outside of the display panel, or combining optical films such as polarizers and quarter-wave plates. These externally mounted solutions significantly increase the overall thickness and volume of the module. Another solution reduces reflection by optimizing the optical parameters of the film materials, but its effectiveness in suppressing multiple reflections caused by complex multi-layered structures and wide-angle incident stray light is limited.

[0004] Therefore, how to suppress ambient light reflection caused by pixel definition layer regions, metal electrodes and lens interfaces within multilayer film structures without significantly increasing device thickness and process complexity has become a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a display panel and display device that solves the problems of existing silicon-based OLED microdisplays being prone to forming virtual images in AR / VR optical systems due to insufficient resistance to ambient stray light, and the increase in device size caused by external anti-reflection elements, thereby achieving the effect of making the microdisplay device thinner and lighter, and suppressing the reflection of wide-angle incident stray light.

[0006] Based on the above concept, the technical solution adopted by this invention is as follows: According to a first aspect of the present invention, a display panel is provided, comprising: An array of light-emitting units, wherein each light-emitting unit includes light-emitting areas of different colors and pixel definition structures disposed between adjacent light-emitting areas; The first anti-reflective layer is disposed on the side of the pixel definition structure away from the substrate; A lens layer is disposed on the side of the light-emitting unit away from the substrate, and the lens layer includes microlens structures that correspond one-to-one with the light-emitting areas; A second anti-reflective layer is disposed between any two adjacent microlens structures.

[0007] In some embodiments, the display panel further includes a color filter film disposed between the light-emitting area and the lens layer, and a third anti-reflective layer disposed on the upper surface at the junction of adjacent color filters.

[0008] In some embodiments, the first antireflective layer, the second antireflective layer, and the third antireflective layer at least partially overlap in a direction perpendicular to the substrate.

[0009] In some embodiments, the materials of the first antireflective layer, the second antireflective layer, and the third antireflective layer include optical absorbing materials or optical interferometric materials.

[0010] Optionally, the optical absorption material includes any one of carbon black resin composite material, ferrous metal nitride, and graphite; The optical interference material includes either tantalum pentoxide or silicon dioxide.

[0011] In some embodiments, the first anti-reflective layer, the second anti-reflective layer, and the third anti-reflective layer are all made of the same material; Alternatively, the material of the first anti-reflective layer may be different from the materials of the second and third anti-reflective layers; Alternatively, the material of the second anti-reflective layer may be different from the materials of the first and third anti-reflective layers; Alternatively, the material of the third anti-reflective layer may be different from the materials of the first and second anti-reflective layers.

[0012] In some embodiments, the optical absorbing material has a light absorption rate greater than 90% in the visible light band.

[0013] In some embodiments, the thickness d and refractive index n of the optical interference material satisfy the following relationship:

[0014]

[0015] in, For wavelength, The refractive index of the film layer in contact with the optical interference material is given. is the refractive index of the film layer in contact with the underlying optical interference material.

[0016] In some embodiments, the display panel further includes an encapsulation layer and a planarization layer; the encapsulation layer is disposed between the light-emitting unit and the color filter film; The planarization layer is disposed between the encapsulation layer and the color filter film, and / or the planarization layer is disposed between the color filter film and the lens layer.

[0017] According to a second aspect of the present invention, a display device is provided, comprising a display panel as described in any of the preceding claims.

[0018] The beneficial effects of this invention are as follows: 1. This invention constructs a multi-level anti-reflection path that works collaboratively between the first, second, and third anti-reflection layers to absorb and reduce stray ambient light incident from different angles layer by layer. Simulation verification shows that this structure can effectively suppress the overall reflectivity of ambient light incident within 60° perpendicular to the panel direction to below 10%, solving the key problem of virtual images generated in AR / VR optical systems due to insufficient anti-stray light capability in existing microdisplays, and improving image contrast and visual clarity.

[0019] 2. The three-layer anti-reflective layer of this invention can be made of carbon black resin composite material with high light absorption rate to achieve rapid and efficient stray light elimination, or it can be made of materials such as tantalum pentoxide based on the principle of optical interference. While ensuring excellent anti-reflective performance, it effectively reduces the absorption of light emitted from the display screen itself, thereby achieving a good balance between suppressing ambient light reflection and maintaining high screen brightness. The entire structure is integrated inside the panel, eliminating the need for external polarizers or anti-reflective glass, which is beneficial for achieving the thinning and miniaturization of the micro-display module. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a display panel according to the present invention; Figure 2 This is a schematic diagram of another display panel structure according to the present invention; Figure 3 These are the simulation results of the reflectivity of stray light incident at different angles according to the present invention.

[0021] Figure label: Display panel 100, another display panel 200, light-emitting unit 1, light-emitting area 11, pixel definition structure 12, first anti-reflection layer 2, lens layer 3, microlens structure 31, second anti-reflection layer 4, encapsulation layer 5, optical resin adhesive 6, substrate 7, color filter film 8, third anti-reflection layer 9, planarization layer 10. Detailed Implementation

[0022] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0023] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, the technical or scientific terms used in this application should be understood in their ordinary sense by one of ordinary skill in the art to which this invention pertains. The words “a” or “one” and similar terms used in this application specification and claims do not indicate a limitation of quantity, but rather indicate the presence of at least one. “A plurality” means two or more. The words “comprising” or “including” and similar terms mean that the element or object preceding “comprising” or “including” covers the element or object listed following “comprising” or “including” and its equivalents, and does not exclude other elements or objects. The words “connected” or “linked” and similar terms are not limited to physical or mechanical connections and can include electrical connections, whether direct or indirect. The words “above” and / or “below” and similar terms are for ease of description only and are not limited to a location or spatial orientation. The singular forms “a,” “the,” and “the” used in this application specification and appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0024] The technical concept of this invention includes: A typical silicon-based OLED microdisplay's film structure, from bottom to top, usually includes: a pixel definition layer, an OLED emitting layer, a thin-film encapsulation layer, a planarization layer, a color filter layer, and a microlens array. In this structure, the pixel definition layer region, the metal cathode of the OLED emitting layer, and other film layers all have highly reflective interfaces. When ambient light (such as indoor lighting or natural light from a window) shines on the display surface, or when stray light emitted by the display itself, which propagates randomly through the optomechanical module and does not participate in imaging, is reflected back onto the display, it penetrates the upper transparent film layers (such as microlenses and planarization layers) and reaches these highly reflective interfaces. The reflected light returns along the original path or an approximate path, carrying the "image" information of these interfaces.

[0025] This application fabricates a first anti-reflective layer above the pixel definition layer (PDL). This layer directly covers the PDL area and any remaining metallic reflective surfaces, intercepting and absorbing stray ambient light that initially penetrates from the bottom layer. Within the microlens array, a second anti-reflective layer is fabricated in the gaps between the microlenses, directly absorbing a large portion of the incident light before it enters the system, and providing a final "pre-ejection" interception of light reflected from below. On the color filter layer (CF), a third anti-reflective layer is fabricated corresponding to the junction area between adjacent filter units (i.e., between sub-pixels), effectively absorbing stray light reflected back from interfaces such as the underlying metal cathode that has already passed through the first line of defense.

[0026] This application sequentially sets up a first, second, and third anti-reflection layer. These three layers are arranged in a coordinated manner in space, forming a multi-level defense path of "absorption-interception-reabsorption" against incident stray light. By designing a multi-layered anti-reflection structure embedded inside the display panel with a coordinated spatial relationship, the technical challenge of simultaneously achieving "high anti-reflection performance" and "thin and compact structure" in microdisplays is solved in an integrated manner.

[0027] This application provides a display panel and display device, including an array of light-emitting units, wherein the light-emitting units include light-emitting areas of different colors and pixel definition structures disposed between adjacent light-emitting areas; The first anti-reflective layer is disposed on the side of the pixel definition structure away from the substrate; A lens layer is disposed on the side of the light-emitting unit away from the substrate, and the lens layer includes microlens structures that correspond one-to-one with the light-emitting areas; A second anti-reflective layer is disposed between any two adjacent microlens structures.

[0028] This invention utilizes a multi-level anti-reflection path that works collaboratively between the first and second anti-reflection layers to absorb and reduce stray ambient light incident from different angles layer by layer. The first anti-reflection layer 2, located above the pixel definition layer of the light-emitting unit, primarily absorbs stray ambient light that has penetrated the surface and reached the lower part of the panel, solving the problem of direct reflection from the underlying reflection source. The second anti-reflection layer 4, located in the outermost microlens gap, acts as the first gate of the optical path, directly absorbing stray light as it enters the panel and ultimately intercepting residual stray light reflected from below. These two layers, one inside and one outside, cover the core path of stray light from incident, penetration, reflection, and emission, forming continuous spatial protection.

[0029] The display panel described in this application is mainly used in the field of near-eye microdisplay, such as VR / AR head-mounted smart display devices, as a display panel for products or components in the field of near-eye microdisplay.

[0030] The display device described in this application includes the display panel as described above.

[0031] The following is in conjunction with the appendix Figures 1 to 3 The display panel and display device provided in this application are described in detail.

[0032] like Figure 1 As shown, this application provides a display panel 100, including an array of light-emitting units 1, wherein the light-emitting unit 1 includes light-emitting areas 11 of different colors and pixel definition structures 12 disposed between adjacent light-emitting areas 11; The first anti-reflection layer 2 is disposed on the side of the pixel definition structure 12 away from the substrate 7; Lens layer 3 is disposed on the side of the light-emitting unit 1 away from the substrate 7, and the lens layer 3 includes microlens structures 31 that correspond one-to-one with the light-emitting areas 11; The second anti-reflective layer 4 is disposed between any two adjacent microlens structures 31.

[0033] The light-emitting region 11 here includes an anode, an organic light-emitting layer, and a cathode disposed above the substrate 7. The anode, serving as the hole injection electrode of the device, receives holes from the driving circuit under an applied electric field and efficiently injects them into the adjacent organic light-emitting layer. The organic light-emitting layer includes a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer; these layers optimize carrier injection, transport, recombination, and light-emitting efficiency. The substrate 7 includes a CMOS substrate and an insulating layer. The CMOS substrate includes pre-fabricated transistors, capacitors, metal interconnects, and other driving circuit components, responsible for receiving display signals and generating current to drive the OLED to emit light. The insulating layer is deposited over the CMOS substrate, physically isolating the underlying CMOS substrate from the upper OLED anode and organic layer, preventing accidental electrical coupling, leakage, or short circuits between the voltage and current signals of the driving circuit and the light-emitting device, ensuring the independence of the pixel circuit.

[0034] The pixel definition structure 12 is used to prevent pixels of different colors from connecting at the edges during the deposition of light-emitting materials of different colors (such as sequentially depositing R, G, and B materials), which could lead to color aliasing and brightness leakage. It also precisely defines the light-emitting area of ​​each red, green, and blue sub-pixel on the substrate 7. To prevent stray light from entering the interior of the display panel 100, a first anti-reflective layer 2 is deposited on the pixel definition structure 12 after the cathode is formed, to reflect the incident stray light.

[0035] The first anti-reflective layer 2 is deposited on the outer surface of the pixel definition structure 12 to ensure that the first anti-reflective layer 2 completely covers the surface of the pixel definition structure 12 without covering the light-emitting area 11. This first anti-reflective layer 2 is mainly used in the lower layer of the device, near the main reflection source, to absorb ambient stray light that has penetrated the upper film layer and reached this location.

[0036] The microlens structure 31 in this embodiment primarily functions to optically collimate and focus the light emitted from the display panel 100, thereby improving light energy utilization efficiency and display performance. Specifically, each microlens structure is aligned with its corresponding single light-emitting area 11 below it. When a pixel emits light, the emitted light is refracted upon reaching the lens layer due to the curved surface structure of the microlens. By rationally designing the radius of curvature, height, and distance from the light-emitting layer of the microlens, large-angle divergent light can be converged, thereby reducing the light emission angle and concentrating the light more towards a direction perpendicular to the panel.

[0037] The second anti-reflective layer 4 is also deposited between any two adjacent microlens structures 31. This ensures that the material of the second anti-reflective layer 4 fills the gap between the microlens structures 31 without covering the curved surface of the lens. This second anti-reflective layer 4 is mainly used at the outermost optical entrance of the display panel 100 to directly absorb ambient stray light incident at a large angle from the outside into the gap between the microlenses, preventing it from entering the interior of the panel and being reflected by the underlying film layer. At the same time, this layer can also intercept and absorb residual stray light reflected from the interior of the panel, providing final blocking before the light is emitted, thereby reducing the overall reflectivity and improving the optical signal-to-noise ratio.

[0038] In this embodiment, an encapsulation layer 5 should also be provided between the light-emitting unit 1 and the lens layer 3 to isolate moisture and oxygen. An optical resin adhesive 6 should also be provided above the microlens structure 31 of the lens layer 3 for bonding the glass cover.

[0039] Furthermore, the materials of the first antireflective layer 2 and the second antireflective layer 4 can be optical absorbing materials or optical interfering materials. The optical absorbing material can be any one of carbon black resin composite materials, ferrous metal nitrides, and graphite; the optical interfering material can be any one of tantalum pentoxide and silicon dioxide. In this embodiment, a representative example using carbon black resin composite materials as the optical absorbing material and tantalum pentoxide as the optical interfering material is described in detail. The technical principles and effects are also applicable to other similar optical absorbing materials or optical interfering materials.

[0040] Specifically, the carbon black resin composite material possesses specific molecules or microstructures that can efficiently absorb photon energy through various mechanisms such as electronic energy level transitions, molecular vibrations, or lattice vibrations. The vast majority of the absorbed light energy is not radiated back as light but is converted into random thermal motion (i.e., heat energy) within the material and gradually dissipated through conduction. The carbon black resin composite material exhibits a light absorption rate greater than 90% in the visible light band.

[0041] When the upper and lower surfaces of the optical interference material reflect light, two beams of reflected light are generated. These two beams of light have an optical path difference due to their different propagation paths. By designing the thickness (d) and refractive index (n) of the thin film, the optical path difference between the two beams of reflected light can be made to be an odd multiple of half the wavelength, so that they are out of phase and their amplitudes cancel each other out, which macroscopically manifests as a significant reduction or even zero in the intensity of the reflected light.

[0042] Specifically, the thickness d and refractive index n of optical interference materials satisfy the following relationship:

[0043]

[0044] in, For wavelength, The refractive index of the film layer in contact with the optical interference material is given. is the refractive index of the film layer in contact with the underlying optical interference material.

[0045] like Figure 2 As shown, this application provides another display panel 200, which has a structure that is substantially the same as that of the display panel 100. The difference is that the other display panel 200 further includes a color filter film 8 disposed between the light-emitting area 11 and the lens layer 3, a third anti-reflection layer 9 disposed on the upper surface of the junction of adjacent color filter films 8, and a planarization layer 10 disposed between the encapsulation layer 5 and the color filter film 8 or between the color filter film 8 and the lens layer 3.

[0046] The third anti-reflective layer 9 here at least partially overlaps with the first anti-reflective layer 2 and the second anti-reflective layer 4 in a direction perpendicular to the substrate. The third anti-reflective layer 9 is used to selectively absorb residual stray light reflected from below in the display panel 200. Some ambient stray light, after penetrating the upper structure, may reach highly reflective interfaces such as the bottom metal cathode or pixel definition layer and be reflected upwards; when this reflected light passes through the color filter film 8 area on its return journey, the third anti-reflective layer 9 located at the junction of the filter units can absorb the light propagating through the non-light-emitting area, thereby further blocking the reflected light from continuing to propagate upwards.

[0047] Furthermore, the materials of the first antireflective layer 2, the second antireflective layer 4, and the third antireflective layer 9 can be the same; for example, the first antireflective layer 2, the second antireflective layer 4, and the third antireflective layer 9 can all be optical absorbing materials. Alternatively, the material of the first antireflective layer 2 can be different from the materials of the second antireflective layer 4 and the third antireflective layer 9; or the material of the third antireflective layer 9 can be different from the materials of the first antireflective layer 2 and the second antireflective layer 4.

[0048] In this embodiment, an optical model is established by combining the actual film thickness of the product. The established optical model includes a light source with an adjustable emission angle to simulate stray light incident from different angles. Simultaneously, an optical receiver is established above the model, and the reflectivity of the display panel 200 to stray light is simulated through optical simulation. The refractive index of the optical absorbing material in the model is set to 1.6, the light absorption rate to 0.95, and the thickness to 0.1 μm. Finally, the reflectivity of stray light incident from different angles is obtained, such as... Figure 3 As shown in the diagram. Simulation verification shows that this structure can effectively suppress the overall reflectivity of ambient light incident within 60° perpendicular to the panel direction to below 10%, solving the key problem of virtual images generated in AR / VR optical systems due to insufficient anti-stray light capability of existing microdisplays, and improving image contrast and visual clarity. The three-layer anti-reflection layer can be made of carbon black resin composite material with high light absorption rate to achieve fast and efficient stray light elimination, or it can be made of materials such as tantalum pentoxide based on the principle of optical interference. While ensuring excellent anti-reflection performance, it effectively reduces the absorption of light emitted by the display itself, thus achieving a good balance between suppressing ambient light reflection and maintaining high screen brightness. The entire structure is integrated inside the panel, eliminating the need for external polarizers or anti-reflection glass, which is conducive to the thinning and miniaturization of microdisplay modules.

[0049] Based on the core concept proposed in this invention, those skilled in the art will understand that the protection scope of the multi-layer anti-reflective structure is not limited to its specific arrangement and thickness parameters. As long as at least two spatially coordinated anti-reflective structures are integrated into the display panel, correspondingly disposed on the pixel definition layer, microlens gap, and color filter layer to suppress ambient stray light reflection, the technical solution falls within the protection scope of this invention. Regardless of whether the anti-reflective layer is single-layer or multi-layer composite, and regardless of whether its material is absorptive, interferometric, or a combination of both, for example, using other black resins, metal oxides, nitrides, or their stacked structures to achieve similar optical functions, all are equivalent transformations or simple extensions of the anti-reflective structure described in this invention. This design, by setting coordinated anti-reflective units at different key positions in the optical path, further achieves the gradual reduction of stray light and optimization of the display optical path, and should all be covered by the patent scope of this invention.

[0050] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. The invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0051] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A display panel, characterized in that, include An array of light-emitting units, wherein each light-emitting unit includes light-emitting areas of different colors and pixel definition structures disposed between adjacent light-emitting areas; The first anti-reflective layer is disposed on the side of the pixel definition structure away from the substrate; A lens layer is disposed on the side of the light-emitting unit away from the substrate, and the lens layer includes microlens structures that correspond one-to-one with the light-emitting areas; A second anti-reflective layer is disposed between any two adjacent microlens structures.

2. A display panel according to claim 1, characterized in that, It also includes a color filter film disposed between the light-emitting area and the lens layer, and a third anti-reflection layer disposed on the upper surface at the junction of adjacent color filters.

3. A display panel according to claim 1 or 2, characterized in that, The first anti-reflective layer, the second anti-reflective layer, and the third anti-reflective layer overlap at least partially in a direction perpendicular to the substrate.

4. A display panel according to claim 1 or 2, characterized in that, The materials of the first anti-reflection layer, the second anti-reflection layer, and the third anti-reflection layer include optical absorbing materials or optical interference materials.

5. A display panel according to claim 4, characterized in that, The optical absorption material includes any one of carbon black resin composite material, ferrous metal nitride, and graphite; The optical interference material includes either tantalum pentoxide or silicon dioxide.

6. A display panel according to claim 4, characterized in that, The first anti-reflective layer, the second anti-reflective layer, and the third anti-reflective layer are all made of the same material; Alternatively, the material of the first anti-reflective layer may be different from the materials of the second and third anti-reflective layers; Alternatively, the material of the second anti-reflective layer may be different from the materials of the first and third anti-reflective layers; Alternatively, the material of the third anti-reflective layer may be different from the materials of the first and second anti-reflective layers.

7. A display panel according to claim 4, characterized in that, The optical absorbing material has a light absorption rate of more than 90% in the visible light band.

8. A display panel according to claim 4, characterized in that, The thickness d and refractive index n of the optical interference material satisfy the following relationship: in, For wavelength, The refractive index of the film layer in contact with the upper layer of the optical interference material is given. is the refractive index of the film layer in contact with the underlying optical interference material.

9. A display panel according to claim 1, characterized in that, It also includes an encapsulation layer and a planarization layer; The encapsulation layer is disposed between the light-emitting unit and the color filter film; The planarization layer is disposed between the encapsulation layer and the color filter film, and / or the planarization layer is disposed between the color filter film and the lens layer.

10. A display device, characterized in that, Includes the display panel described in any one of claims 1-9.

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