Display panel, preparation method thereof and display device

Abstract

This application discloses a display panel and its fabrication method and display device, comprising a substrate, an organic light-emitting layer, a light-adjusting layer, a light-extracting layer, and a polarizing layer stacked together. The organic light-emitting layer includes an array of sub-pixels, and the light-adjusting layer includes an array of lenses. The orthographic projection of each lens onto the substrate at least partially overlaps with the orthographic projection of each sub-pixel onto the substrate. The lenses are used to receive and converge light emitted from the organic light-emitting layer, which includes first directional light and second directional light. The light-extracting layer is used to reflect the first directional light and transmit the second directional light. The polarizing layer is used to convert the second directional light received from the light-extracting layer into linearly polarized light.

Description

Technical Field

[0001] This application generally relates to the field of display technology, and specifically to a display panel and its manufacturing method, and a display device. Background Technology

[0002] With the increasing popularity of electronic display products among consumers, it is necessary to improve the privacy protection of display screens when browsing various information using electronic devices in public places. Furthermore, privacy displays can also be applied in the field of in-vehicle displays, using privacy structures to prevent entertainment content and bright light from the passenger screen from distracting the driver.

[0003] However, current privacy protection methods typically involve directly attaching a privacy screen protector to the outside of the screen. While this does reduce brightness at wide viewing angles and provides privacy, it also reduces the brightness and resolution of the front display. Furthermore, for portable electronic devices such as laptops and mobile phones, reducing power consumption for extended use is crucial, and increasing screen light output is an effective way to achieve this. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a display panel and its manufacturing method, as well as a display device, which can realize privacy protection, reduce power consumption, and improve display effect.

[0005] In a first aspect, this application provides a display panel, comprising a substrate, an organic light-emitting layer, a light-modulating layer, a light-extracting layer, and a polarizing layer stacked together, wherein...

[0006] The organic light-emitting layer includes a plurality of sub-pixels arranged in an array, and the light-modulating layer includes a plurality of lenses arranged in an array, wherein the orthographic projection of the lenses on the substrate at least partially overlaps with the orthographic projection of the sub-pixels on the substrate;

[0007] The lens is used to receive and converge the light emitted by the organic light-emitting layer, the light emitted by the organic light-emitting layer including first directional light and second directional light;

[0008] The light extraction layer is used to reflect the first directional light and transmit the second directional light; the polarizing layer is used to convert the second directional light emitted from the light extraction layer into linearly polarized light.

[0009] Optionally, the organic light-emitting layer includes a first electrode layer, an organic functional layer, and a second electrode layer stacked together, wherein at least one of the first electrode layer and the second electrode layer is a semi-transparent and semi-reflective layer, and the semi-transparent and semi-reflective layer is used to receive and reflect the first directional light from the light extraction layer.

[0010] Optionally, the first electrode layer is disposed on the side of the organic functional layer near the light-modulating layer, and the second electrode layer is disposed on the side of the organic functional layer away from the light-modulating layer. The first electrode layer is a semi-transparent and semi-reflective layer, and the second electrode layer is a semi-transparent material or an opaque material.

[0011] Optionally, the sub-pixel includes a red sub-pixel, a green sub-pixel, and a blue sub-pixel, and each of the sub-pixels satisfies that the full width at half maximum (FWHM) of the photoluminescence spectrum is ≤30nm.

[0012] Optionally, the light adjustment layer further includes a plurality of light-shielding units disposed in the same layer as the lens, the light-shielding units being disposed between the lens and adjacent lenses, and a gap being provided between the light-shielding units and the lens.

[0013] Optionally, the orthogonal projection of the lens onto the substrate is located within the orthogonal projection range of the sub-pixel onto the substrate.

[0014] Optionally, it further includes a display defining layer disposed between the substrate and the organic light-emitting layer, the pixel defining layer having a plurality of openings for defining the sub-pixels;

[0015] The orthographic projection of the light-shielding unit on the substrate does not overlap with the orthographic projection of the opening on the substrate, and the distance between the boundary of the orthographic projection of the light-shielding unit on the substrate and the boundary of the orthographic projection of the opening on the substrate is no greater than 3μm.

[0016] Optionally, it also includes an encapsulation layer disposed between the organic light-emitting layer and the light-modulating layer;

[0017] The light-adjusting layer includes a protective layer covering the lens and the light-shielding unit, the protective layer filling the gap between the light-shielding unit and the lens;

[0018] The lens, the encapsulation layer, and the protective layer satisfy the following condition: n1>n2>n3, where n1 is the refractive index of the lens, n2 is the refractive index of the encapsulation layer, and n3 is the refractive index of the protective layer.

[0019] Secondly, this application provides a method for manufacturing a display panel, used to manufacture a display panel as described in any of the above descriptions, the method comprising:

[0020] An organic light-emitting layer, a light-modulating layer, a light-extracting layer, and a polarizing layer are sequentially formed on the substrate.

[0021] Thirdly, this application provides a display device including a display panel as described in any of the above.

[0022] The technical solutions provided by the embodiments of this application may include the following beneficial effects:

[0023] The display panel provided in this application embodiment, through the mutually matched organic light-emitting layer, light adjustment layer and light extraction layer, enables the light emitted by the organic light-emitting layer to be focused by the light adjustment layer to form narrow-angle focused light, and then incident on the light extraction layer to be adjusted into circularly polarized light with a single rotation direction, or converted back into linearly polarized light, effectively reducing the ambient light reflected by the display panel and increasing the contrast of the display panel. Attached Figure Description

[0024] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0025] Figure 1 A schematic diagram of the structure of a display panel provided for an embodiment of this application;

[0026] Figure 2 A schematic diagram of the structure of an organic light-emitting layer provided for an embodiment of this application;

[0027] Figure 3 A schematic diagram of the dimensions of a lens provided for an embodiment of this application;

[0028] Figure 4 Comparison results of the display effect of a display panel provided for embodiments of this application;

[0029] Figure 5 A flowchart illustrating a method for manufacturing a display panel, as provided in an embodiment of this application. Detailed Implementation

[0030] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] Please see details. Figure 1 This application provides a display panel, including a substrate 100, an organic light-emitting layer 200, a light-modulating layer 400, a light-extracting layer 500, and a polarizing layer 600 stacked together, wherein...

[0033] The organic light-emitting layer 200 includes a plurality of sub-pixels 220 arranged in an array, and the light-adjusting layer 400 includes a plurality of lenses 410 arranged in an array. The orthographic projection of the lens 410 on the substrate 100 at least partially overlaps with the orthographic projection of the sub-pixels 220 on the substrate 100.

[0034] The lens 410 is used to receive and converge the light emitted by the organic light-emitting layer 200, the light emitted by the organic light-emitting layer 200 including first directional light and second directional light;

[0035] The light extraction layer 500 is used to reflect the first directional light and transmit the second directional light; the polarizing layer 600 is used to convert the second directional light emitted from the light extraction layer 500 into linearly polarized light.

[0036] In this embodiment, the organic light-emitting layer 200, the light adjustment layer, and the light extraction layer 500 are matched with each other, so that the light emitted by the organic light-emitting layer 200 can be focused by the light adjustment layer to form a narrow-angle focused light, and then incident on the light extraction layer 500 to be adjusted into circularly polarized light with a single rotation direction, or converted back into linearly polarized light, effectively reducing the ambient light reflected by the display panel and increasing the contrast of the display panel.

[0037] In this embodiment, the light extraction layer 500 can be made of chiral liquid crystal molecules. Chiral liquid crystal molecules are liquid crystal molecules with chiral centers, characterized by the presence of carbon atoms with asymmetric chiral centers in their molecular structure. Due to the presence of these chiral centers, these liquid crystal molecules form a helical structure. This helical structure gives chiral liquid crystal molecules many optical properties not found in ordinary liquid crystal molecules, allowing them to selectively reflect light of a fixed wavelength range and a fixed direction of rotation. In this embodiment, cholesteric liquid crystal is used as an example of a light extraction layer 500 for illustrative purposes.

[0038] Based on the direction of the helix, cholesteric liquid crystal films are divided into left-handed and right-handed cholesteric liquid crystals. Left-handed cholesteric liquid crystals exhibit left-handed circular polarization, while right-handed cholesteric liquid crystals exhibit right-handed circular polarization. When cholesteric liquid crystals are distributed in a planar texture, they exhibit selective reflection characteristics. Left-handed circular polarization reflects left-handed circularly polarized light with a wavelength similar to the pitch of the cholesteric liquid crystal, but allows right-handed circularly polarized light and light of other wavelengths to pass through. Right-handed circular polarization reflects right-handed circularly polarized light with a wavelength similar to the pitch of the cholesteric liquid crystal, but allows left-handed circularly polarized light and light of other wavelengths to pass through.

[0039] Cholesteric liquid crystals consist of many layers of molecules, each layer with molecules aligned in the same direction, but adjacent layers are slightly rotated, forming a helical structure. The distance between two layers with identical molecular arrangements after a 360° rotation is called the pitch of the cholesteric liquid crystal. Depending on the specific needs, chiral agents can be added to the cholesteric liquid crystal to alter the pitch.

[0040] Depending on the type of cholesteric liquid crystal used in the light extraction layer 500, the light extraction layer 500 is used to reflect one of left-handed and right-handed circularly polarized light and transmit the other. In this embodiment, a left-handed cholesteric liquid crystal is used as an example for illustrative description. The light extraction layer 500 is used to reflect left-handed circularly polarized light and transmit right-handed circularly polarized light. In this application, a chiral liquid crystal layer is used as the light extraction layer 500 to prevent the absorption of light with different polarization directions in the mixed light, which would reduce the light efficiency. By reflecting the first polarization direction light back to the display panel for light modulation, the light utilization rate is improved.

[0041] In this embodiment, the polarizing layer 600 can be a linear polarizer, causing the second-direction light (right-hand circularly polarized light) to be converted into linearly polarized light before emission. The polarizing layer 600 can also be a quarter-wave plate layer, causing the circularly polarized light passing through the liquid crystal layer to be converted into linearly polarized light through phase delay before emission. Of course, the polarizing layer 600 can also employ other configurations to convert circularly polarized light into linearly polarized light, and this application is not limited in this regard. The polarizing layer 600 also prevents external ambient light from entering the display panel and being reflected into the observer's eyes under strong ambient light conditions, which would significantly reduce the contrast of the display device and thus affect the display effect.

[0042] In this embodiment of the invention, the type of display panel is not limited. In some embodiments, the display panel is an electroluminescent display panel. The electroluminescent display panel can be an organic electroluminescent display panel or a quantum dot light-emitting display (QLED) panel. In other embodiments, the display panel is a liquid crystal display panel. In this application, an OLED display panel is used as an example for illustrative purposes.

[0043] In some embodiments, the substrate 100 is a sub-substrate. In other embodiments, the substrate 100 includes a sub-substrate and thin-film transistors and driving circuits disposed on the sub-substrate. The thin-film transistor includes a source, a drain, an active layer, a gate, and a gate insulating layer. The driving circuit includes pixel driving circuits, GOA (Gate On Array) circuits, and IC (Integrated Circuit) driving circuits, etc.

[0044] In some embodiments, a pixel defining layer 210 is provided on the substrate 100, and the pixel defining layer 210 is provided with a plurality of openings for defining the sub-pixels 220. The arrangement of the sub-pixels 220 is not limited in this embodiment; the sub-pixels 220 can be arranged in a stripe pattern, an island pattern, a mosaic pattern, or a triangular pattern. The shape of the sub-pixels 220 is not limited in this embodiment; the shape of each sub-pixel 220 does not have to be polygonal. For example, the shape of the sub-pixels 220 can be circular or elliptical, and this embodiment of the invention does not limit this.

[0045] In this application, to achieve privacy protection for the display panel, control is exercised through three aspects: changing the direction of light, polarization direction, and brightness. This achieves a good privacy protection effect. By changing the light pattern, a narrow viewing angle is achieved; by optimizing the polarization direction, light utilization is improved; and by using a brightness ratio, the display device can be used normally by those looking directly at it, while viewers at other angles will be disturbed by the brightness ratio, thus enhancing the privacy protection effect.

[0046] In this embodiment of the application, the sub-pixel 220 includes a red sub-pixel 220, a green sub-pixel 220, and a blue sub-pixel 220, and each of the sub-pixels 220 satisfies that the full width at half maximum (FWHM) of the photoluminescence spectrum is ≤30nm.

[0047] To achieve the privacy protection effect, this application can also adjust the electroluminescence spectrum of the sub-pixel 220 to give it the property of a narrow emission peak. By adjusting the light properties in the organic light-emitting layer 200 to match the properties of the chiral liquid crystal in the light extraction layer 500, the light extraction efficiency can be improved when the converged light with the narrow emission peak enters the light extraction layer 500, thereby improving the light utilization rate. The full width at half maximum (FWHM) of the photoluminescence spectrum of each sub-pixel 220 in the organic light-emitting layer 200 is no greater than 30 nm. In addition, due to the microcavity effect of the light-emitting element, the luminous intensity under a wide viewing angle can be reduced, thereby improving the narrow viewing angle effect.

[0048] The red-green-blue sub-pixel 220 includes a cathode, an anode, and multiple organic functional layers 223, wherein the organic functional layer 223 includes at least one organic light-emitting layer 200. In this invention, the organic functional layer 223 refers to a layer with light-emitting function disposed within an organic compound layer between the anode and the cathode. The host material in each light-emitting layer is the material used as the main component among the materials contained in the light-emitting layer. More specifically, the host material is the material constituting the light-emitting layer in greater than 50% by mass among the materials contained in each light-emitting layer. The guest material refers to a material with a mass ratio less than that of the host material. The guest material can be selected as a fluorescent material, a compound material that emits light in the visible light region when returning from a singlet excited state to the ground state.

[0049] In the embodiments of this application, excited states include singlet excited states and triplet excited states, wherein a singlet excited state refers to a singlet state with excitation energy. Furthermore, the S1 level is the lowest level of the singlet excited levels, referring to the excitation energy level of the lowest singlet excited state (S1 state). Similarly, a triplet excited state refers to a triplet state with excitation energy. Finally, the T1 level is the lowest level of the triplet excited levels, referring to the excitation energy level of the lowest triplet excited state (T1 state).

[0050] In one embodiment of this application, the organic light-emitting layer 200 includes a first compound and a second compound, wherein the first compound is a host material and the second compound is a guest material. In order to achieve a narrow emission peak of the organic light-emitting layer 200, the content ratio of the host material and the guest material and the excited state properties of the materials can be adjusted to control the emission peak of the light-emitting layer.

[0051] For example, the S1 and T1 energy levels of the host material are both higher than those of the guest material. The host material should have a high singlet state to facilitate energy transfer, and a high triplet T1 level to prevent energy reversion. The mass of the host material accounts for ≥70% of the mass of the organic light-emitting layer 200, and the mass of the guest material accounts for ≤30% of the mass of the organic light-emitting layer 200. The guest material can be a metal complex of iridium, platinum, palladium, or cerium, or a fluorescent material, etc.

[0052] In some other embodiments of this application, the organic light-emitting layer 200 includes a first compound, a second compound, and a third compound. The first compound is the host material, the second compound is the auxiliary material, and the third compound is the guest material. The auxiliary material refers to a compound material that has the function of converting a triplet excited state into a singlet excited state for light emission. The auxiliary material can be selected from sensitizer materials. The mass ratio of the sensitizer material to the total mass of the host material and the sensitizer material is ≤30%, and the mass ratio of the guest material to the total mass of the host material and the sensitizer material is ≤5%. The sensitizer material is a thermally activated delayed fluorescence material containing at least one carbazole group and at least one cyano group. The guest material is a fluorescent material containing at least one boron atom and at least one nitrogen atom.

[0053] In this design, the S1 and T1 energy levels of the host material are both greater than those of the sensitizer material, and the S1 and T1 energy levels of the sensitizer material are both greater than those of the guest material. The energy difference between the S1 and T1 energy levels of the sensitizer material is less than 0.3 eV. By controlling the sensitizer material to have a small singlet-triple energy level difference, it can not only accept the energy transferred from the host material to S1 via Forster energy and the energy transferred to T1 via short-range Dexter energy, but also convert triplet excitons to singlet excitons via anti-system crossing (RISC), and then transfer them to the fluorescent guest material S1 via Forster energy. Finally, fluorescence is emitted by the singlet exciton radiative transition of the fluorescent guest material, which further improves the Forster energy and the proportion of singlet excitons, while suppressing triplet excitons, effectively reducing exciton loss and improving the device luminescence efficiency.

[0054] The overlap area between the absorption spectrum of the guest material and the emission spectrum of the sensitizer material is greater than or equal to 10%. The larger the overlap area, the more favorable it is for energy transfer. The emission spectrum of the host material and the absorption spectrum of the guest material have good overlap. In the embodiments of this application, by limiting the absorption spectrum and emission spectrum of the auxiliary material, the energy transfer between the host and the guest can be improved. Such energy transfer is more thorough and the external quantum efficiency (EQE) is higher.

[0055] In the embodiments of this application, for the red sub-pixel 220, the emission peak is located at 620nm~640nm and FWHM≤30nm; for the green sub-pixel 220, the emission peak is located at 520nm~540nm and FWHM≤30nm; for the blue sub-pixel 220, the emission peak is located at 450nm~470nm and FWHM≤30nm.

[0056] In this embodiment, the light extraction layer 500 can reflect a fixed wavelength range. If the wavelength of the incident light matches the pitch of the cholesteric liquid crystal, the cholesteric liquid crystal allows incident light with the same direction of rotation to pass through and reflects incident light with the opposite direction of rotation. If the wavelength of the incident light does not match the pitch of the cholesteric liquid crystal, the cholesteric liquid crystal allows all incident light to pass through. Therefore, the reflection or transmission of incident light can be changed by adjusting the pitch.

[0057] The peak wavelength λ of the light reflected by the light extraction layer 500 max =n avg *P, where n avg Let P be the average refractive index of the liquid crystal and P be the pitch of the helical structure. The spectral width of the reflected light is Δλ = Δn * P, where Δn is the difference between the refractive indices of the ordinary and extraordinary rays.

[0058] For example, n avg The wavelength can be limited to between 1.2 and 1.8, Δn between 0 and 0.2, and pitch P between 0 and 3 μm. The peak wavelength λ of the reflected light from the light extraction layer is... max The value range is 550±20nm. The spectral width Δλ of the reflected light from the light extraction layer ranges from 450 to 640nm. The transmittance of the light extraction layer is 50%±20% at 440–480nm, 50%±20% at 510–550nm, and 50%±20% at 610–650nm.

[0059] In this embodiment, the organic light-emitting layer 200 can reflect the first axial light reflected from the light extraction layer 500 through electrodes, thereby improving the extraction efficiency of the light extraction layer 500. Furthermore, by utilizing the microcavity effect of the organic light-emitting layer 200, a narrow viewing angle is achieved, increasing the luminous intensity. In this embodiment, the organic light-emitting layer 200 includes a first electrode layer 221, an organic functional layer 223, and a second electrode layer 222 stacked together. At least one of the first electrode layer 221 and the second electrode layer 222 is a semi-transparent and semi-reflective layer, which is used to receive and reflect the first axial light from the light extraction layer 500.

[0060] For example, the first electrode layer 221 is disposed on the side of the organic functional layer 223 near the light-adjusting layer 400, and the second electrode layer 222 is disposed on the side of the organic functional layer 223 away from the light-adjusting layer 400. The first electrode layer 221 is a semi-transparent and semi-reflective layer, and the second electrode layer 222 is a semi-transparent material or an opaque material.

[0061] Due to the light transmission and reflection characteristics of the first electrode layer 221 and the second electrode layer 222, the light emitted by the light-emitting layer is reflected back and forth between the first electrode layer 221 and the second electrode layer 222, forming a microcavity effect. This microcavity effect strengthens the resonant wavelength, improving the color purity and luminous efficiency of the OLED device. When light exits from the first electrode layer 221 and reaches the light extraction layer 500, the light extraction layer 500 reflects the first directional light. This first directional light, after reflection from the surface of the first electrode layer 221, becomes second directional light and re-enters the light extraction layer 500 and passes through.

[0062] It is understood that the first electrode layer 221 can be a cathode and the second electrode layer 222 can be an anode. Of course, the first electrode layer 221 and the second electrode layer 222 can be interchanged, and this application does not limit this. For example, as... Figure 2 As shown, each of the sub-pixels 220 includes, from bottom to top, at least an anode (second electrode layer 222), a hole injection layer 10 (HIL), a hole transport layer 20 (HTL), an electron blocking layer 30 (EBL), an emitting layer 40 (EML), a hole blocking layer 50 (HBL), an electron transport layer 60 (ETL), an electron injection layer 70 (EIL), and a cathode (first electrode layer 221).

[0063] When the display panel is an organic electroluminescent display panel, the light-emitting layer is an organic light-emitting layer 200; when the display panel is a quantum dot electroluminescent display panel, the light-emitting layer is a quantum dot light-emitting layer. Under a certain voltage drive, electrons and holes from the anode 500 and cathode 600 of the sub-pixel 220 are injected into the electron injection layer 70 and hole injection layer 10, respectively. The electrons and holes then migrate through the electron transport layer 60 and hole transport layer 20 to the light-emitting layer 40, where they meet to form excitons and excite the light-emitting molecules. These molecules then emit visible light through radiative relaxation.

[0064] Specifically, the first electrode layer 221 is a semi-transparent and semi-reflective material, which may include, for example, a semi-transparent and semi-reflective layer formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a mixture thereof; the second electrode layer 222 is an opaque metallic material, for example, an opaque metallic material formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a mixture thereof.

[0065] Different colors of light have different intrinsic reflection wavelengths, and therefore require different microcavity lengths. The microcavity length is typically adjusted based on the color emitted by each pixel. Microcavity length refers to the distance between two light-reflecting layers. A longer microcavity length enhances longer wavelengths of light, while a shorter microcavity length enhances shorter wavelengths. For OLED display panels using R (red), G (green), and B (blue) colors, the wavelengths are: blue (450nm–470nm), green (520nm–540nm), and red (620nm–640nm). The microcavity length for blue is less than that for green, which is less than that for red.

[0066] In the embodiments of this application, although the description of each pixel includes red sub-pixel 220, green sub-pixel 220, and red sub-pixel 220, the present invention is not limited thereto. The color of sub-pixel 220 can also be described as a first color, a second color, and a third color, and the first color, second color, and third color can also be cyan, magenta, and yellow. In addition, the pixel may include white sub-pixel 220.

[0067] The display panel further includes an encapsulation layer 300 disposed between the organic light-emitting layer 200 and the light-adjusting layer 400. The encapsulation layer 300 prevents external water and oxygen from entering the display panel through the opening area, thus avoiding damage to the display function caused by water and oxygen intrusion. The encapsulation layer 300 can be a thin film encapsulation (TFE). The encapsulation layer 300 can be composed of multiple layers of encapsulation materials; this application is not limited to this. For example, the encapsulation layer 300 may include a first inorganic encapsulation layer 300, an organic encapsulation layer 300, and a second inorganic encapsulation layer 300 stacked on the organic light-emitting layer 200.

[0068] In this application, the lens 410 on the light adjustment layer can have various structures, such as a convex lens 410, a lens array 410, or other structures with light-gathering functions, which are not limited here. In this application, the arrangement of the lenses 410 in the light adjustment layer 400 can correspond one-to-one with the arrangement of the sub-pixels 220. For example, the lens 410 can be a microlens 410. Through this one-to-one correspondence, the light emitted by the sub-pixels 220 on the organic light-emitting layer 200 can be individually controlled. The light is emitted from the organic light-emitting layer 200, transmitted through the encapsulation layer 300, exits from the encapsulation layer 300, and enters the light adjustment layer. The light adjustment layer can converge the light and enhance the brightness within a certain range.

[0069] The planar convex lens 410 includes a base for receiving incident light and a protrusion for focusing the light; the protrusion of the planar convex lens 410 faces the light extraction layer 500; the base is parallel to the plane of the light extraction layer 500. It is understood that the size of the lens 410 is not limited in this embodiment. In different embodiments, the size of the lens 410 can be adjusted according to the need for a narrow viewing angle. In different embodiments, the narrow viewing angle range of the display panel can be 45° to 135°. More preferably, the narrow viewing angle range of the display panel can be 80° to 100°. For example, when the sub-pixel 220 is placed within the focal length of the lens 410, the light emitted by the sub-pixel 220 will form scattered light after passing through the lens 410, at which time the viewing angle of the light is relatively wide; in addition, when the sub-pixel 220 is placed at the focal length of the lens 410, the light emitted by the sub-pixel 220 will form parallel light after passing through the lens 410, at which time the viewing angle of the light is very narrow.

[0070] The planar convex lens 410 can be formed from acrylic UV-curable resin, epoxy UV-curable resin, or thermosetting resin. For example, the material of lens 410 is selected from polyethylene terephthalate (PET), polycarbonate (PC), polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), and polymethyl methacrylate (PMMA).

[0071] In this embodiment, the light adjustment layer 400 further includes a plurality of light-shielding units 420 disposed on the same layer as the lens 410. The light-shielding units 420 are disposed between the lens 410 and adjacent lenses 410, and a gap is provided between the light-shielding units 420 and the lens 410. The light adjustment layer 400 includes a protective layer 430 covering the lens 410 and the light-shielding units 420, filling the gap between the light-shielding units 420 and the lens 410. The light adjustment layer 400 allows the first directional light reflected by the light extraction layer 500 to pass through the lens 410 and through the gap to reach the first electrode layer 221 of the organic light-emitting layer 200, preventing direct absorption of light by the light-shielding units 420 and improving light utilization.

[0072] The protective layer 430 is a transparent polymer material, such as polystyrene (PS), polymethyl methacrylate (PMMA), polycarbonate (PC), polysulfone (PSF or PSU), etc. The protective layer 430 ensures the overall flatness of the light adjustment layer. Furthermore, by adjusting the refractive index matching between the upper and lower layers of the lens 410, a better light adjustment effect is achieved.

[0073] In this embodiment, the lens 410, the encapsulation layer 300, and the protective layer 430 satisfy the following condition: n1 > n2 > n3, where n1 is the refractive index of the lens 410, n2 is the refractive index of the encapsulation layer 300, and n3 is the refractive index of the protective layer 430. In this application, adjusting the refractive indices of each medium along the light path can improve the converging effect of light emitted from the organic light-emitting layer 200. Furthermore, by matching the refractive indices, the light can be controlled over a wide viewing angle to improve light utilization.

[0074] In this embodiment, the array arrangement of the light-shielding unit 420 on the light-adjusting layer 400 corresponds to that of the lens 410, and the light-shielding unit 420 separates the multiple lenses 410. By setting the light-shielding unit 420 and the interval between the light-shielding unit 420 and the lens 410, the first axial light reflected from the light extraction layer 500 can be reflected again into the first electrode layer 221 of the organic light-emitting layer 200. Total internal reflection can be performed on light entering the interval position from the light-emitting layer with an excessive incident angle, reducing large-angle light emission, while preventing light from being directly absorbed by the light-shielding unit 420, thereby improving light utilization.

[0075] The light-shielding unit 420 can be made of a black light-absorbing material; preferably, the black light-absorbing material is any one of black epoxy resin, molybdenum oxide, carbon black, and titanium dioxide. It should be understood that the aforementioned black light-absorbing material is used to absorb light and can be a variety of materials not limited to those described in this embodiment. The light-shielding unit 420 can be formed on the light-adjusting layer of the same layer as the lens 410 by coating or other methods, and a corresponding pattern can be formed by a patterning process.

[0076] For example, such as Figure 3 As shown, the lens 410 satisfies the following relationship:

[0077]

[0078]

[0079]

[0080] Where f is the focal length of the lens 410, n1 is the refractive index of the lens 410, n2 is the refractive index of the encapsulation layer 300 material near the light adjustment layer, n3 is the refractive index of the protective layer 430 material covering the lens 410, r is the radius of curvature of the lens 410, D is the width of the lens 410, and Δn is the refractive index difference.

[0081] From the above formula, we can see that It can be seen that Δn and D and Both are directly proportional, and the width and focal length of lens 410 can be determined by the refractive index difference Δn.

[0082] In the embodiments of this application, the refractive index n1 of lens 410 is 1.80 to 1.95; the refractive index n2 of encapsulation layer 300 is 1.70 to 1.79; and the refractive index n3 of protective layer 430 is < 1.75.

[0083] In this application, the spacing between the lens 410 and the light-shielding unit 420 can be formed in various ways, for example, by reducing the inner diameter of the lens 410. In an optional embodiment, the orthographic projection of the lens 410 onto the substrate 100 is located within the orthographic projection range of the sub-pixel 220 onto the substrate 100. By reducing the inner diameter of the lens 410, the emission angle of light on the organic light-emitting layer 200 can be controlled.

[0084] In another alternative embodiment, the spacing can also be formed by reducing the size of the light-shielding unit 420. For example, the orthographic projection of the light-shielding unit 420 on the substrate 100 does not overlap with the orthographic projection of the opening on the substrate 100, and the distance between the boundary of the orthographic projection of the light-shielding unit 420 on the substrate 100 and the boundary of the orthographic projection of the opening on the substrate 100 is not greater than 3 μm, thereby achieving a reflectivity of less than 7% for the display panel.

[0085] In the sub-pixels 220 prepared in the organic light-emitting layer 200 in Example 1 of this application, the emission peak λEL of R sub-pixel 220 is 625nm and FWHM is 28nm; the emission peak λEL of G sub-pixel 220 is 524nm and FWHM is 26nm; and the emission peak λEL of B sub-pixel 220 is 460nm and FWHM is 18nm.

[0086] The microlens 410 is made of transparent silicone, n1 = 1.89; the inorganic layer in the encapsulation layer 300 is made of silicon oxynitride, n2 = 1.76; and the protective layer is made of organic polymer material, n3 = 1.70.

[0087] The light-shielding unit 420 has a recess value of 2 μm, and the display panel has a reflectivity of 6.5%. The light extraction layer 500 uses a cholesteric liquid crystal film with a transmittance of 40% at 460 nm, 44% at 530 nm, and 48% at 630 nm.

[0088] Comparative Example 1 shows the display panel structure in the prior art, and the comparison results of the display effects are as follows: Figure 4 As shown, due to the microcavity effect, the luminance of each OLED device decreases with viewing angle (luminance-decay, L-decay). In the figure, L-decay@45° represents the light attenuation at a viewing angle of 45°, and L-decay@30° represents the light attenuation at a viewing angle of 30°. It can be seen that Example 1 reduces power consumption by 31%, and L-decay@45° exceeds 90%, demonstrating good privacy protection.

[0089] like Figure 5 As shown, this application also provides a method for manufacturing a display panel, used to manufacture a display panel as described in any of the above descriptions, the method comprising:

[0090] An organic light-emitting layer 200, a light-modulating layer 400, a light-extracting layer 500, and a polarizing layer 600 are sequentially formed on a substrate 100.

[0091] The structure includes forming a pixel defining layer 210 on the substrate 100 before forming the organic light-emitting layer 200, and forming an opening on the pixel defining layer 210 to define the sub-pixel 220 by patterning. The organic light-emitting layer 200 is formed on the pixel defining layer 210. The organic light-emitting layer 200 may include a second electrode layer 222, a hole injection layer 10, a hole transport layer 20, an electron blocking layer 30, a light-emitting layer 40, a hole blocking layer 50, an electron transport layer 60, an electron injection layer 70, and a first electrode layer 221 formed sequentially.

[0092] An encapsulation layer 300 is formed on the organic light-emitting layer 200; a lens 410 and a light-shielding unit 420 are formed on the encapsulation layer 300; a protective layer 430 is formed on the lens 410 and the light-shielding unit 420; a light extraction layer 500 is formed on the protective layer 430; and a polarizing layer 600 is formed on the light extraction layer 500.

[0093] The light extraction layer 500 can be formed by coating a mixture of helical liquid crystal molecules with photopolymerization properties and a chiral agent with specific chiral orientation, followed by photocuring to form the light extraction layer 500 with a specific chiral orientation; or by directly coating a polymer material with fixed chiral characteristics to form the light extraction layer 500; or by bonding a pre-prepared cholesteric liquid crystal film onto the light conditioning layer 400 to form the light extraction layer 500.

[0094] In an exemplary embodiment of this application, the fabrication process of the light extraction layer 500 can be to form the light extraction layer 500 with a specific chiral orientation by photocuring. Specifically, it includes: coating an alignment layer → pre-curing → main curing → alignment → post-drying → coating liquid crystal material → low-temperature drying of solvent → UV curing.

[0095] It should be noted that, in the embodiments of this application, the alignment layer is an alignment structure used to form the light extraction layer 500 orientation, and the material of the alignment layer is selected from substances with alignment capabilities. For example, a PI alignment layer. The PI alignment layer has an anchoring effect on liquid crystal molecules, which can make the liquid crystal align according to the angle between the branches and the main chain in the polymer molecules of the PI liquid, that is, the direction of the pretilt angle. For example, it may include: coating, photolithography, exposure, development, baking, and rubbing alignment processes. Of course, other methods in the prior art can also be used to achieve liquid crystal alignment, and this application is not limited to this.

[0096] Specifically, the liquid crystal material of the light extraction layer 500 is a polymeric liquid crystal composition, which includes a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent and an adhesion enhancer, as well as a polymeric liquid crystal compound.

[0097] The purpose of the aforementioned low-temperature drying solvent is to remove the solvent from the cholesteric liquid crystal solution while retaining the cholesteric liquid crystal molecules. The purpose of the aforementioned UV (ultraviolet light) curing is to solidify the cholesteric liquid crystal molecules into a film. The aforementioned baking method can include various approaches. For example, the aforementioned baking is a low-temperature baking, where the temperature is below 95°C.

[0098] Based on the same inventive concept, this application provides a display device, including a display panel as described above. The specific structure of the display panel has been described in detail in the above embodiments and will not be repeated here. The display device in this application can be a television, or a PC, smartphone, tablet computer, e-book reader, MP3 (Moving Picture Experts Group Audio Layer III) player, MP4 (Moving Picture Experts Group Audio Layer IV) player, portable computer, or other devices with display functions.

[0099] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0100] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0101] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for descriptive purposes only and is not intended to limit the invention. Terms such as “set” appearing herein can refer to either a component being directly attached to another component or a component being attached to another component via an intermediary. A feature described in one embodiment herein may be applied, alone or in combination with other features, to another embodiment, unless that feature is not applicable in that other embodiment or is otherwise stated.

[0102] The present invention has been described through the above embodiments; however, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit the present invention to the described embodiments. Those skilled in the art will understand that many variations and modifications can be made based on the teachings of the present invention, and all such variations and modifications fall within the scope of protection claimed by the present invention.

Claims

1. A display panel, characterized in that, It includes a substrate, an organic light-emitting layer, a light-modulating layer, a light-extracting layer, and a polarizing layer stacked together, wherein, The organic light-emitting layer includes a plurality of sub-pixels arranged in an array, and the light-modulating layer includes a plurality of lenses arranged in an array, wherein the orthographic projection of the lenses on the substrate at least partially overlaps with the orthographic projection of the sub-pixels on the substrate; The lens is used to receive and converge the light emitted by the organic light-emitting layer, the light emitted by the organic light-emitting layer including first directional light and second directional light; The light extraction layer is used to reflect the first directional light and transmit the second directional light; the polarizing layer is used to convert the second directional light received from the light extraction layer into linearly polarized light. The light adjustment layer also includes a plurality of light-shielding units disposed in the same layer as the lens, and the light-shielding units are disposed between the lens and the adjacent lens; It also includes an encapsulation layer disposed between the organic light-emitting layer and the light-modulating layer; The light-adjusting layer includes a protective layer covering the lens and the light-shielding unit; The lens, the encapsulation layer, and the protective layer satisfy the following condition: n1>n2>n3, where n1 is the refractive index of the lens, n2 is the refractive index of the encapsulation layer, and n3 is the refractive index of the protective layer. A gap is provided between the light-shielding unit and the lens, and the protective layer fills the gap between the light-shielding unit and the lens to achieve the second reflection of the first axial light reflected from the light extraction layer into the first electrode layer of the organic light-emitting layer, as well as the total internal reflection of the light entering the gap position from the light-emitting layer, and to prevent the light from being directly absorbed by the light-shielding unit.

2. The display panel according to claim 1, characterized in that, The organic light-emitting layer includes a first electrode layer, an organic functional layer, and a second electrode layer stacked together. At least one of the first electrode layer and the second electrode layer is a semi-transparent and semi-reflective layer, which is used to receive and reflect the first directional light from the light extraction layer.

3. The display panel according to claim 2, characterized in that, The first electrode layer is disposed on the side of the organic functional layer close to the light-modulating layer, and the second electrode layer is disposed on the side of the organic functional layer away from the light-modulating layer. The first electrode layer is a semi-transparent and semi-reflective layer, and the second electrode layer is a semi-transparent material or an opaque material.

4. The display panel according to claim 1, characterized in that, The sub-pixels include red sub-pixels, green sub-pixels, and blue sub-pixels, and each sub-pixel satisfies the requirement that the full width at half maximum (FWHM) of the photoluminescence spectrum is ≤30nm.

5. The display panel according to claim 1, characterized in that, The orthogonal projection of the lens onto the substrate lies within the orthogonal projection range of the sub-pixel onto the substrate.

6. The display panel according to claim 1, characterized in that, It also includes a pixel defining layer disposed between the substrate and the organic light-emitting layer, the pixel defining layer having a plurality of openings for defining the sub-pixels; The orthographic projection of the light-shielding unit on the substrate does not overlap with the orthographic projection of the opening on the substrate, and the distance between the boundary of the orthographic projection of the light-shielding unit on the substrate and the boundary of the orthographic projection of the opening on the substrate is no greater than 3μm.

7. A method for manufacturing a display panel, characterized in that, The method for preparing a display panel as described in any one of claims 1-6 includes: An organic light-emitting layer, a light-modulating layer, a light-extracting layer, and a polarizing layer are sequentially formed on the substrate.

8. A display device, characterized in that, Includes the display panel as described in any one of claims 1-6.

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