Optical extraction structure, display panel and display device

Abstract

This invention provides an optical extraction structure, a display panel, and a display device. The optical extraction structure includes: a protective layer suitable for being laid on light-emitting pixels; and an optical adjustment layer disposed on the protective layer. The refractive index of the optical adjustment layer changes with variations in light intensity or electric field. In response to the change in the refractive index of the optical adjustment layer, the refraction of light emitted from the light-emitting pixels through the optical adjustment layer changes accordingly. By utilizing the variability of the refractive index of the optical adjustment layer, under different ambient light intensities, the optical matching layer can refract or totally reflect some light, thereby achieving both improved viewing angle and increased efficiency.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to an optical extraction structure, a display panel, and a display device. Background Technology

[0002] With the rapid development of technology, display media have become an important part of people's lives. Organic light-emitting diode (OLED) displays, due to their self-emissive nature, possess superior color and image quality.

[0003] In existing OLED devices, besides improving the luminous efficiency of the device itself, efficiency can also be improved by adjusting the optical film layer. However, improving both viewing angle and efficiency cannot be achieved simultaneously through optical film layer adjustments or MLA structures. In other words, current OLED devices face the technical challenge of simultaneously improving viewing angle and efficiency through their light extraction structures. Summary of the Invention

[0004] In view of this, the present invention aims to provide a touch optical extraction structure, display panel and display device that can improve device efficiency while ensuring optical viewing angle, so as to solve the technical problem that viewing angle improvement and efficiency improvement cannot be achieved at the same time in the prior art.

[0005] This invention provides an optical extraction structure, comprising: a protective layer and an optical adjustment layer. The protective layer is suitable for being deposited on a light-emitting pixel. The optical adjustment layer is disposed on the protective layer, and the refractive index of the optical adjustment layer changes with changes in light intensity or electric field; wherein, in response to the change in the refractive index of the optical adjustment layer, the refraction of light emitted from the light-emitting pixel after passing through the optical adjustment layer changes with the change in the refractive index of the optical adjustment layer.

[0006] In one embodiment, the optical extraction structure further includes an optical matching layer disposed on the optical adjustment layer within a groove located on the periphery of the area opposite the opening of the light-emitting pixel.

[0007] Preferably, the light emitted by the light-emitting pixel toward the optical matching layer is at least partially totally reflected by the trench sidewalls.

[0008] Preferably, the side of the groove is an inclined surface, wherein the angle between the inclined surface and the bottom surface of the optical matching layer is determined by the upper limit of the refractive index of the optical adjustment layer, the refractive index of the optical matching layer, the width of the light-emitting pixel, and the size parameters of the optical extraction structure.

[0009] In one embodiment, the bottom edge of the slope coincides with the opening boundary of the light-emitting pixel.

[0010] Preferably, the angle between the inclined surface and the bottom surface of the optical matching layer ranges from 30° to 90°.

[0011] In one embodiment, the inner surface of the optical matching layer is perpendicular to the plane where the light-emitting pixel is located.

[0012] Preferably, the bottom of the optical matching layer is flush with the bottom of the optical adjustment layer.

[0013] Preferably, the bottom edge of the inner side of the optical matching layer coincides with the opening boundary of the light-emitting pixel.

[0014] In one embodiment, the refractive index range of the optical adjustment layer is 1.3 to 2.1; and the refractive index range of the optical matching layer is 1.5 to 1.6.

[0015] Another aspect of the present invention provides a display panel, comprising: a substrate, light-emitting pixels, and an optical extraction structure as described in the above embodiments. The light-emitting pixels are disposed on the substrate. A protective layer of the optical extraction structure is disposed on the light-emitting pixels.

[0016] In one embodiment, the optical extraction structure further includes an optical matching layer, which is disposed in a groove on the optical adjustment layer located on the periphery of the area opposite the opening of the light-emitting pixel. The side of the groove is a slope, and the angle between the slope and the bottom surface of the optical matching layer is determined by the upper limit of the refractive index of the optical adjustment layer, the refractive index of the optical matching layer, the width of the light-emitting pixel, and the size parameters of the encapsulation layer and the pixel definition layer.

[0017] Preferably, the angle between the inclined surface and the bottom surface of the optical matching layer satisfies the following formula:

[0018]

[0019] Where θ represents the angle between the inclined plane and the bottom surface, d1 represents the width of the light-emitting pixel, d2 represents the projection width of the inclined plane of the pixel definition layer groove on the bottom surface, d3 represents the sum of the thicknesses of the pixel definition layer and the encapsulation layer, n1 represents the refractive index of the optical matching layer, and n2 represents the upper limit of the refractive index of the optical adjustment layer.

[0020] Preferably, the display panel further includes: an encapsulation layer disposed on the light-emitting pixels; wherein the encapsulation layer is a protective layer for the optical extraction structure;

[0021] Preferably, the display panel further includes a pixel definition layer disposed between the light-emitting pixels and the substrate, wherein a portion of the pixel definition layer is recessed to form a trapezoidal groove with a cross-sectional shape that is wider at the top and narrower at the bottom, and the pixel definition layer is adapted to define the opening of the light-emitting pixels.

[0022] In one embodiment, the width of the light-emitting pixel ranges from 10 to 20 μm.

[0023] Preferably, the thickness of the pixel definition layer ranges from 1 to 3 μm, and the thickness of the encapsulation layer ranges from 2 to 3 micrometers.

[0024] Preferably, the projection width of the pixel definition layer groove slope on the bottom surface ranges from 5 to 10 μm.

[0025] Preferably, the thickness of the optical matching layer is in the range of 4 to 5 μm.

[0026] Preferably, the thickness of the optical adjustment layer is in the range of 8–12 μm.

[0027] In one embodiment, the light-emitting pixel opening is made of an electrosensitive material, and the display panel further includes a cathode and an electric field electrode. The cathode is disposed between the pixel definition layer and the protective layer. The electric field electrode is disposed above the optical adjustment layer, and the electric field electrode, in conjunction with the cathode, generates an electric field for changing the refractive index of the optical adjustment layer.

[0028] Preferably, the electric field electrode is disposed above the optical matching layer.

[0029] Preferably, the display panel further includes an anode disposed between the pixel definition layer and the substrate.

[0030] Another aspect of the present invention provides a display device, including a display panel as described in the above embodiments.

[0031] According to the optical extraction structure, display panel, and display device of the present invention, an optical adjustment layer with a refractive index that varies with the ambient light intensity is disposed on the light-emitting pixel, and an optical matching layer with a fixed refractive index is disposed in the region outside the corresponding opening region on the optical adjustment layer. By utilizing the variability of the refractive index of the optical adjustment layer, under different ambient light intensities, the optical matching layer can refract part of the light and emit it from the large viewing angle of the light-emitting pixel, thereby increasing the light emission viewing angle; or, the optical matching layer can totally reflect part of the light and emit it from the positive viewing angle of the light-emitting pixel, thereby enhancing the light extraction rate at the positive viewing angle. Attached Figure Description

[0032] Figure 1 A cross-sectional view of the optical extraction structure according to an embodiment of the present invention.

[0033] Figure 2 yes Figure 1 The diagram shows the working principle of the optical extraction structure.

[0034] Figure 3 A cross-sectional view of the optical extraction structure according to another embodiment of the present invention.

[0035] Figure 4 This is a cross-sectional view of the optical extraction structure according to another embodiment of the present invention.

[0036] Figure 5 This is a partial structural and dimensional schematic diagram of the optical extraction structure according to an embodiment of the present invention.

[0037] Figure 6 This is a cross-sectional view of the optical extraction structure according to another embodiment of the present invention.

[0038] Figure 7 This is a schematic diagram of the wiring of the electric field electrodes of the display panel according to an embodiment of the present invention.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1-Substrate;

[0041] 2-Anode;

[0042] 3-Emitting pixels;

[0043] 4-Encapsulation layer;

[0044] 5-Optical adjustment layer;

[0045] 6-Optical matching layer;

[0046] 7-pixel definition layer;

[0047] 8-Cathode;

[0048] 9-Electric field electrode;

[0049] 10-Electrode routing. Detailed Implementation

[0050] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. In the accompanying drawings and the following description, at least some well-known structures and techniques have not been shown in order to avoid unnecessarily obscuring the invention; and, for clarity, the dimensions of some structures may be exaggerated. Furthermore, the features, structures, or characteristics described below may be combined in any suitable manner in one or more embodiments.

[0051] In the description of this invention, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this 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, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the embodiments of the present invention. It should also be noted in the description of the present invention that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0053] In existing technologies, current optical films cannot simultaneously achieve both efficiency and viewing angle. Taking mobile phones as an example, current mobile phone usage scenarios can be roughly divided into indoor and outdoor. In indoor scenarios, the display panel does not require very high luminous brightness, and users are more concerned about its viewing angle performance. However, in outdoor usage scenarios, the display panel needs higher forward luminous emission, and viewing angle performance is less important.

[0054] Based on the above considerations, this invention provides an optical extraction structure above the emitting pixels, comprising an optical adjustment layer and an optical matching layer disposed on the optical adjustment layer. The orthographic projection of the optical matching layer is located above the pixel definition layer. The refractive index of the optical adjustment layer changes with the ambient light intensity, while the refractive index of the optical matching layer remains constant. The light extraction of the optical extraction structure is achieved by utilizing refraction and total internal reflection at the interface between the optical adjustment layer and the optical matching layer, enabling switching between a wide viewing angle and a normal viewing angle.

[0055] Figure 1 A cross-sectional view of the optical extraction structure according to an embodiment of the present invention. Figure 2 yes Figure 1 The diagram shows the working principle of the optical extraction structure.

[0056] According to one aspect of the inventive concept of the present invention, an optical extraction structure is provided, comprising: a protective layer and an optical adjustment layer 5. The protective layer is suitable for being deposited on a light-emitting pixel 3. The optical adjustment layer 5 is disposed on the protective layer, and the refractive index of the optical adjustment layer 5 changes with changes in light intensity or electric field. In response to the change in the refractive index of the optical adjustment layer 5, the refraction of light emitted from the light-emitting pixel 3 after passing through the optical adjustment layer 5 changes with the change in the refractive index of the optical adjustment layer 5. Light incident on the side of the optical matching layer 6 is refracted and exits from the light-emitting pixel 3 at a large angle to increase the light emission angle, or light incident on the side of the optical matching layer 6 from the light-emitting pixel 3 undergoes at least partial total internal reflection and exits from the frontal angle of the light-emitting pixel 3 to enhance the light extraction rate at the frontal angle.

[0057] In this embodiment, by setting an optical adjustment layer 5 with a refractive index that varies with the ambient light intensity on the light-emitting pixel 3, the angle at which the light emitted by the light-emitting pixel 3 is refracted after passing through the optical adjustment layer 5 is changed by utilizing the variability of the refractive index of the optical adjustment layer 5. This causes some of the light to be refracted and emitted from the large angle of the light-emitting pixel 3, thereby increasing the light emission angle. Alternatively, some of the light is totally reflected and emitted from the positive angle of the light-emitting pixel 3, thereby enhancing the light extraction rate at the positive angle.

[0058] In one embodiment, the optical extraction structure further includes an optical matching layer 6, which is disposed on the optical adjustment layer 5 in a groove located on the periphery of the opening of the light-emitting pixel 3. The refractive index of the optical matching layer 6 is fixed.

[0059] In one embodiment, as the refractive index of the optical matching layer 5 changes, the light emitted by the light-emitting pixel 3 toward the optical matching layer 5 can be at least partially totally reflected by the trench sidewalls.

[0060] In one embodiment, the optical adjustment layer 5 in the optical extraction structure is an optical control material, optionally characterized by a material whose refractive index changes under electric or light conditions. Further optionally, the refractive index of the optical adjustment layer 5 gradually increases with changes in light or electric field. Generally, the higher the light / electric field intensity, the greater the range of refractive index variation; however, there is a material saturation refractive index, after which the refractive index no longer increases.

[0061] In one embodiment, as the ambient light intensity increases from low to high, the refractive index of the optical adjustment layer 5 gradually increases from its minimum value until it reaches its saturation refractive index. During this process, the refractive index of the optical adjustment layer 5 is lower than that of the optical matching layer 6 in the first half of the process, and higher than that of the optical matching layer 6 in the second half.

[0062] In this embodiment, as Figure 2 As shown in the figure, (a) is the working principle diagram under high ambient light intensity. For example, in the outdoor environment during the day, the ambient light intensity is too high, which affects the display effect of the display panel. Based on this, improving the light extraction rate of the display panel at the positive viewing angle to ensure that the user can clearly see the image on the display panel is the most important and highest priority.

[0063] To achieve the above objectives, the optical extraction structure provided in this embodiment of the invention adjusts the refractive index of the optical adjustment layer 5 to be greater than that of the optical matching layer 6 under the action of ambient light or an additional electric field. The light generated by the light-emitting pixel 3 is partially emitted from the normal viewing angle and partially incident at an angle on the interface between the optical adjustment layer 5 and the optical matching layer 6. Since the refractive index of the optical adjustment layer 5 is relatively large, it belongs to the light from the optically denser medium to the optically less dense medium. Under certain conditions, when the incident angle meets certain conditions, the light incident at an angle on the interface between the optical adjustment layer 5 and the optical matching layer 6 undergoes total internal reflection and is then emitted from the normal viewing angle of the optical extraction structure.

[0064] In this embodiment, as Figure 2 As shown in the figure, (b) illustrates the working principle under low ambient light conditions, such as indoor or nighttime use environments. In these environments, the ambient light intensity is low, and the display panel does not require a high forward light extraction rate. Users prioritize user experience in this context. Taking a mobile phone as an example, in this usage environment, the ambient light intensity does not affect the normal display of the panel. Users prioritize comfort when using the phone, such as watching videos or movies while doing other tasks. In this case, the phone is generally not placed in front of the user but rather to the side. Therefore, the optical extraction structure requires a higher angle of light extraction and better performance in capturing light over a wide viewing angle.

[0065] To achieve the above objectives, the optical extraction structure provided in this embodiment of the invention adjusts the refractive index of the optical adjustment layer 5 to be less than that of the optical matching layer 6 under the action of ambient light or an additional electric field. The light generated by the light-emitting pixel 3 is partially emitted from the normal viewing angle and partially incident at an angle on the interface between the optical adjustment layer 5 and the optical matching layer 6. Since the refractive index of the optical adjustment layer 5 is small, it belongs to the light from the optically less dense medium to the optically denser medium. Total internal reflection will not occur at this interface, only refraction will occur, and the emission angle will be further increased, that is, the effect of viewing angle scattering will be further increased.

[0066] As can be seen from the above, the optical extraction structure provided by the embodiments of the present invention can be adaptively adjusted for different usage environments, switching between forward light extraction state and wide-angle scattering state to meet the different needs of users in different usage environments.

[0067] In one embodiment, under wide-angle scattering conditions, the refractive indices of the optical adjustment layer 5 and the optical matching layer 6 are comparable, or the refractive index of the optical adjustment layer 5 is slightly greater than that of the optical matching layer 6, which can also achieve the above effect. The specific calculation needs to be based on the specific size parameters of the component. It is only necessary to ensure that the maximum incident angle of the light-emitting pixel 3 toward the above interface is less than the critical angle of total internal reflection.

[0068] In one embodiment, the protective layer is an insulating layer disposed on the light-emitting pixel 3 to electrically isolate the light-emitting pixel 3 from the optical adjustment layer 5 and prevent current from affecting the optical adjustment layer 5. Optionally, the encapsulation layer 4 disposed on the light-emitting pixel 3 can be used as the protective layer, or a separate protective layer can be disposed on the light-emitting pixel 3, with the encapsulation layer 4 located on top of the optical adjustment layer 5 and the optical matching layer 6.

[0069] In one embodiment, the refractive index of the optical adjustment layer 5 can change with the intensity of light or with the applied electric field. Specifically, the material of the optical adjustment layer 5 can be a nonlinear optical material, including inorganic nonlinear optical materials, organic nonlinear optical materials, and other nonlinear optical materials (e.g., liquid crystals, semiconductor particle clusters, organic / inorganic composites, and multilayer materials). Inorganic nonlinear optical materials include lithium niobate crystals, potassium titanate phosphate crystals, potassium dihydrogen phosphate crystals, potassium niobate crystals, borate series materials, perovskite materials, and semiconductor materials. Organic nonlinear optical materials include organic low-molecular-weight nonlinear optical materials (e.g., urea and its derivatives, Schiff base compounds, azo compounds, stilbene compounds, etc.), polymer nonlinear optical materials (e.g., host-guest polymers, side-chain and main-chain polymers, cross-linked polymers, conjugated polymers), and metal-organic complex nonlinear optical materials (e.g., metallocene complexes, metal carbonyl complexes, etc.).

[0070] In one embodiment, the host-guest polymer is a nonlinear optical material formed by mixing a guest organic conjugated molecule with a high nonlinear optical coefficient and a host polymer. It not only has the advantages of a large nonlinear optical coefficient and fast response speed, but its specific properties can also be adjusted through molecular design.

[0071] In one embodiment, the side-chain and main-chain type polymer is formed by bonding chromophore molecules to the polymer main chain or side chain through covalent or ionic bonds to form a side-chain or main-chain type polymer nonlinear optical material, which has high orientation stability and nonlinear optical properties.

[0072] In one embodiment, the cross-linked polymer fixes chromophore molecules in the polymer network through a cross-linking reaction, thereby improving the orientation stability and nonlinear optical properties of the material.

[0073] In one embodiment, the conjugated polymer is, for example, polydiacetylene (PDA), polyacetylene (PA), polythiophene (PTh), polyphenylacetylene (PPV), etc. These polymer molecules have a high degree of delocalization and a large nonlinear optical coefficient, while maintaining good transparency.

[0074] Below are some examples of specific materials used in optical adjustment layers:

[0075] (1) English name: poly-9-(3-(ethyldimethylsilyl)propyl)-2,7-dimethyl-9H-carbazole.

[0076] The structural formula is:

[0077]

[0078] (2) English name: poly-4-(ethyldimethylsilyl)-N,N-di-p-tolylaniline.

[0079] The structural formula is:

[0080]

[0081] (3) English name: benzyl butyl phthalate.

[0082] The structural formula is:

[0083]

[0084] (4) English name: 9-ethyl-2-phenyl-9H-carbazole.

[0085] The structural formula is:

[0086]

[0087] (5) English name: 2-(4-(azepan-l-yl)-2-methylbenzylidene)malononitrile.

[0088] The structural formula is:

[0089]

[0090] (6) English name: 2-(4-(azepan-l-yl)-2,5-difluorobenzylidene)malononitrile.

[0091] The structural formula is:

[0092]

[0093] (7) English name: 2-(3-cyano-4-(4-(dihexylamino)phenyl)-5,5-dimethyl-2,5-dihydrofuran-2-yl)malononitrile.

[0094] The structural formula is:

[0095]

[0096] Figure 3 A cross-sectional view of the optical extraction structure according to another embodiment of the present invention.

[0097] In one embodiment, such as Figure 1 and Figure 3 As shown, the inner surface of the optical matching layer 6 is a slope. The angle between the slope and the bottom surface of the optical matching layer 6 is determined by the upper limit of the refractive index of the optical adjustment layer 5, the refractive index of the optical matching layer 6, the width of the light-emitting pixel 3, and the size parameters of the optical extraction structure.

[0098] For ease of description and IE, in this invention, the side of the optical matching layer 6 closest to the opening of the light-emitting pixel 3 is defined as the inner side, and the side furthest from the opening is defined as the outer side.

[0099] In this embodiment, by setting the inner surface of the optical matching layer 6 as an inclined plane, the incident angle of the light generated by the light-emitting pixel 3 at the interface between the optical adjustment layer 5 and the optical matching layer 6 can be increased, thereby improving the total reflectance of the optical extraction structure in the forward light extraction state, that is, improving the light extraction rate at the forward viewing angle in this state; at the same time, it can increase the incident angle of the light generated by the light-emitting pixel 3 at the interface between the optical adjustment layer 5 and the optical matching layer 6, thereby improving the refraction angle of the optical extraction structure in the large viewing angle scattering state, that is, further improving the large viewing angle scattering degree.

[0100] In one embodiment, the light-emitting pixel 3 is disposed on the pixel definition layer 7, which is generally trapezoidal in cross-sectional shape and used to define the opening area of ​​the pixel. The light emitted from the region near the bottom corner of the trapezoid on the light-emitting pixel 3 has the smallest incident angle when it reaches the inner surface of the opposite optical matching layer 6. By adjusting the size of the optical extraction structure, when the optical adjustment layer 5 reaches its saturated refractive index, the light emitted from this region can undergo total internal reflection at the interface, thereby achieving maximum positive angle light extraction.

[0101] In one embodiment, the bottom edge of the slope coincides with the opening boundary of the light-emitting pixel 3, meaning the trench on the optical adjustment layer is a through-groove. During the manufacturing process, after the optical adjustment layer 5 is fabricated, a grooving operation needs to be performed on it. By controlling the trench depth, the thickness of the optical matching layer 6 can be controlled. Specific grooving methods can include photolithography and dry / wet etching, which will not be elaborated upon here.

[0102] In this embodiment, by increasing the thickness of the optical matching layer 6, all light emitted from the non-pixel opening area passes through the optical matching layer 6. The light is then processed by the optical matching layer 6, either by causing total internal reflection to increase the light extraction at the positive viewing angle, or by causing refraction to increase the light scattering angle to increase the light emission viewing angle.

[0103] Preferably, the angle between the inclined surface and the bottom surface of the optical matching layer 6 ranges from 30° to 90°. By selecting a matching material for the optical extraction structure, both the positive viewing angle light extraction rate and the large viewing angle emission angle can be taken into account.

[0104] Figure 4 This is a cross-sectional view of the optical extraction structure according to another embodiment of the present invention.

[0105] In one embodiment, such as Figure 4 As shown, the inner surface of the optical matching layer 6 is perpendicular to the plane where the light-emitting pixel 3 is located.

[0106] In this embodiment, the groove has a rectangular cross-sectional shape, which simplifies its fabrication process. More preferably, the bottom of the optical matching layer 6 is flush with the bottom of the optical adjustment layer 5. That is, when fabricating the groove on the optical adjustment layer 5, the groove is directly cut to the bottom of the optical adjustment layer 5, allowing the optical matching layer 6 to cover the entire optical adjustment layer 5 vertically, facilitating total internal reflection or scattering of light over a wider angle. Even more preferably, the bottom edge of the inner side of the optical matching layer 6 coincides with the opening boundary of the light-emitting pixel 3. That is, the bottom edge of the inner side of the optical matching layer 6 coincides with the top edge of the trapezoidal groove, maximizing total internal reflection or refraction of light emitted from the light-emitting pixel 3 towards the area outside the pixel opening, thereby improving the working efficiency of the optical extraction structure.

[0107] In one embodiment, the refractive index of the optical adjustment layer 5 ranges from 1.3 to 2.1; and the refractive index of the optical matching layer 6 ranges from 1.5 to 1.6.

[0108] In one embodiment, the saturated refractive index of the material of the optical adjustment layer 5 is generally limited to 2.1.

[0109] In one embodiment, the material of the optical adjustment layer 5 satisfies the following condition:

[0110]

[0111] Where I represents irradiance, Id represents dark radiation, and t represents illumination duration;

[0112] Preferably, Δn is 0.6.

[0113] In one embodiment, the quality factor of the optical adjustment layer 5 is preferably 1.5 to 2. The formula for calculating the quality factor is as follows:

[0114]

[0115] Where n0 represents the refractive index of the material, and r eff ε represents the effective photoelectric coefficient, and ε represents the dielectric constant.

[0116] According to another aspect of the inventive concept of the present invention, a display panel is also provided, such as... Figure 1 , Figure 3 and Figure 4 As shown, it includes: a substrate 1, a light-emitting pixel 3, and an optical extraction structure as described in the above embodiment. The light-emitting pixel 3 is disposed on the substrate 1. A protective layer of the optical extraction structure is disposed on the light-emitting pixel 3.

[0117] In this embodiment, the improvements of the display panel compared to the prior art and the beneficial technical effects are similar to the optical extraction structure in the previous embodiment, and will not be described in detail here.

[0118] Preferably, the display panel further includes a pixel definition layer 7 disposed between the light-emitting pixel 3 and the substrate 1, wherein a portion of the pixel definition layer 7 is recessed to form a trapezoidal groove with a cross-sectional shape that is wider at the top and narrower at the bottom, and the pixel definition layer 7 is suitable for defining the opening area of ​​the light-emitting pixel 3.

[0119] In one embodiment, the optical extraction structure further includes an optical matching layer 6, which is disposed on the optical adjustment layer 5 in a groove located on the periphery of the opening area opposite to the light-emitting pixel 3. The side of the optical groove is a slope, and the angle between the slope and the bottom surface of the optical matching layer 6 is determined by the upper limit of the refractive index of the optical adjustment layer 5, the refractive index of the optical matching layer 6, the width of the light-emitting pixel 3, and the size parameters of the encapsulation layer 4 and the pixel definition layer 7.

[0120] Preferably, the angle between the inclined surface and the bottom surface of the optical matching layer 6 satisfies the following formula.

[0121]

[0122] Where θ represents the angle between the inclined plane and the bottom surface, d1 represents the width of the light-emitting pixel, d2 represents the projection width of the inclined plane of the pixel definition layer groove on the bottom surface, d3 represents the sum of the thicknesses of the pixel definition layer and the encapsulation layer, n1 represents the refractive index of the optical matching layer, and n2 represents the upper limit of the refractive index of the optical adjustment layer.

[0123] Preferably, the display panel further includes an encapsulation layer 4, which is disposed on the light-emitting pixels 3; wherein, the encapsulation layer 4 is a protective layer for the optical extraction structure.

[0124] In this embodiment, by using the encapsulation layer 4 as a protective layer, it can be adapted to existing display panel production lines, thereby reducing production costs.

[0125] Figure 5 This is a partial structural and dimensional schematic diagram of the optical extraction structure according to an embodiment of the present invention.

[0126] In one embodiment, such as Figure 3 and Figure 5 As shown, the angle between the inclined plane and the bottom surface of the optical matching layer 6 is designed based on the dimensions of the optical extraction structure. Figure 5 As shown, the width of the light-emitting pixel 3 is d1, L1 is the light emitted from the leftmost end of the light-emitting pixel, passes through the upper right vertex of the trapezoidal structure and hits the optical matching layer 6, and L2 is the light emitted from the light-emitting pixel 3 that is not L1 and can hit the inner surface of the optical matching layer 6.

[0127] d2 represents the projected width of the beveled surface of the pixel definition layer 7 on the bottom surface, and d3 represents the sum of the thicknesses of the pixel definition layer 7 and the encapsulation layer 4. Therefore, it can be concluded that...

[0128] θ1 is the angle between ray L1 and the plane containing the emitting pixel 3. θ1 and θ2 are alternate interior angles, and θ2 and θ3 are vertical angles, that is, θ1 = θ2 = θ3.

[0129] The refractive index of optical matching layer 6 is n2, the refractive index of optical adjustment layer 5 is n1, θ4 is the angle between the inclined plane to be designed and the bottom surface of optical matching layer 6, θ5 is the incident angle of light L1, and θ6 is the complementary angle of θ5, that is, θ6 = 90° - θ5.

[0130] Depend on Figure 5 The relationship between the angles can be derived as follows:

[0131] θ4=180°-(180°-θ3-θ6)=180°-(180°-θ3-θ6)=θ3+θ6=90°+θ1-θ5.

[0132] Assuming θ5 is the critical angle for total internal reflection, then That is, we can obtain the following formula:

[0133]

[0134] In this design, ray L1 is the ray with the smallest incident angle that strikes the interface between the optical adjustment layer 5 and the optical matching layer 6. Other rays that can strike this interface (the farthest being L2) all have incident angles greater than θ5, resulting in total internal reflection, thus achieving the improvement objective of this invention. Based on the above, the angle between the inclined surface and the bottom surface of the optical matching layer 6 can be determined by using the dimensional and material parameters of the optical extraction structure and related structures.

[0135] In one embodiment, the width of the light-emitting pixel 3 ranges from 10 to 20 μm.

[0136] Preferably, the thickness of the pixel definition layer 7 is in the range of 1 to 3 μm, and the thickness of the encapsulation layer 4 is in the range of 2 to 3 micrometers.

[0137] Preferably, the projection width of the groove slope of the pixel definition layer 7 on the bottom surface is in the range of 5 to 10 μm.

[0138] Preferably, the thickness of the optical matching layer 6 is in the range of 4 to 5 μm.

[0139] Preferably, the thickness of the optical adjustment layer 5 is in the range of 8 to 12 μm, and more preferably, the thickness of the optical adjustment layer 5 is 10 μm.

[0140] Preferably, the detection range between two adjacent optical matching layers 6 is 15–30 μm.

[0141] Figure 6 This is a cross-sectional view of the optical extraction structure according to another embodiment of the present invention.

[0142] In one embodiment, the opening of the light-emitting pixel 3 is made of an electrosensitive material, such as... Figure 6 As shown, the display panel also includes a cathode 8 and an electric field electrode 9. The cathode 8 is disposed between the pixel definition layer 7 and the protective layer. The electric field electrode 9 is disposed above the optical adjustment layer 5, and the electric field electrode 9, in conjunction with the cathode 8, generates an electric field to change the refractive index of the optical adjustment layer 5.

[0143] In this embodiment, a controllable electric field is generated on the optical matching layer 6 by the cathode 8 and the electric field electrode 9. The magnitude of the electric field is changed by adjusting the current intensity, thereby changing the refractive index of the optical adjustment layer 5, and finally realizing the switching between the forward light extraction state and the wide-angle scattering state.

[0144] In one embodiment, changing the refractive index of the optical adjustment layer 5 by using an external electric field offers better controllability compared to adaptively changing the refractive index by ambient light intensity. Furthermore, changing the refractive index of the optical adjustment layer 5 by using an external electric field allows for manual adjustment and selection based on user commands, resulting in a better user experience.

[0145] Preferably, the electric field electrode 9 is disposed above the optical matching layer 6, and the electric field electrode 9 is electrically isolated from the optical adjustment layer 5 by the optical matching layer 6 to prevent the current from affecting the optical adjustment layer 5.

[0146] Preferably, the display panel further includes an anode disposed between the pixel definition layer 7 and the substrate 1. The anode cooperates with the cathode 8 to drive the light-emitting pixels 3 to emit light.

[0147] Figure 7 This is a schematic diagram of the wiring of the electric field electrode 9 of the display panel in an embodiment of the present invention.

[0148] In one embodiment, such as Figure 7 As shown, a plurality of light-emitting pixels 3 are arranged in an array on the display panel. Each light-emitting pixel 3 is equipped with the optical extraction structure provided in the aforementioned embodiment. The electric field electrodes 9 on each optical matching layer 6 are connected in parallel through electrode traces.

[0149] In one embodiment, the display panel can be either a flexible or a rigid display panel. The light extraction method of the display panel can be either bottom-emitting or top-emitting.

[0150] In one embodiment, the display panel can be applied to any product or component with display functionality, such as a television, digital camera, mobile phone, watch, tablet computer, laptop computer, navigator, e-book reader, player, laptop computer, in-vehicle computer, desktop computer, or set-top box.

[0151] Another aspect of the present invention provides a display device, including a display panel as described in the above embodiments.

[0152] It should be noted that the display device can be a variety of electronic display products, including but not limited to at least one of the following: mobile phone, tablet computer, e-book reader, media player, digital camera, laptop computer, in-vehicle computer, desktop computer, set-top box, smart TV, and wearable device.

[0153] In addition, depending on actual needs, the display device may also include other structures such as a touch panel.

[0154] Since the display device of this application embodiment includes the above-mentioned... Figures 1 to 7 All the technical solutions in the embodiments shown can achieve at least all the above-mentioned technical effects, and will not be repeated here.

[0155] It should be noted that, for clarity, the complete structure of the display panel and display device described above is not presented. To achieve the necessary functions of the display panel or display device, those skilled in the art can configure other structures according to specific application scenarios.

[0156] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An optical extraction structure, characterized in that, include: A protective layer suitable for application on luminescent pixels; An optical adjustment layer is disposed on the protective layer, and the refractive index of the optical adjustment layer changes with the change of light intensity or electric field. An optical matching layer is disposed on the optical adjustment layer within a groove located on the periphery of the area opposite the opening of the light-emitting pixel. The sidewall of the groove is inclined, and the angle between the inclined surface and the bottom surface of the optical matching layer satisfies the following formula: Where θ represents the angle between the inclined plane and the bottom surface, d1 represents the width of the light-emitting pixel, d2 represents the projection width of the inclined plane of the pixel definition layer groove on the bottom surface, d3 represents the sum of the thicknesses of the pixel definition layer and the encapsulation layer, n1 represents the refractive index of the optical matching layer, and n2 represents the upper limit of the refractive index of the optical adjustment layer. In response to a change in the refractive index of the optical adjustment layer, the refraction of light emitted by the light-emitting pixel after passing through the optical adjustment layer changes with the change in the refractive index of the optical adjustment layer.

2. The optical extraction structure according to claim 1, characterized in that, The light emitted by the light-emitting pixel toward the optical matching layer is at least partially totally reflected by the trench sidewall.

3. The optical extraction structure according to claim 2, characterized in that, The bottom edge of the inclined plane coincides with the opening boundary of the light-emitting pixel.

4. The optical extraction structure according to claim 3, characterized in that, The angle between the inclined plane and the bottom surface of the optical matching layer ranges from 30° to 90°.

5. The optical extraction structure according to claim 1, characterized in that, The inner surface of the optical matching layer is perpendicular to the plane where the light-emitting pixel is located.

6. The optical extraction structure according to claim 5, characterized in that, The bottom of the optical matching layer is flush with the bottom of the optical adjustment layer.

7. The optical extraction structure according to claim 5, characterized in that, The bottom edge of the inner side of the optical matching layer coincides with the opening boundary of the light-emitting pixel.

8. The optical extraction structure according to claim 1, characterized in that, The refractive index range of the optical adjustment layer is 1.3 to 2.1; the refractive index range of the optical matching layer is 1.5 to 1.

6.

9. A display panel, characterized in that, include: substrate; Light-emitting pixels are disposed on the substrate; The optical extraction structure as described in any one of claims 1 to 8, wherein the protective layer of the optical extraction structure is disposed on the light-emitting pixel.

10. The display panel according to claim 9, characterized in that, The optical extraction structure further includes an optical matching layer, which is disposed on the optical adjustment layer in a groove located on the periphery of the area opposite the opening of the light-emitting pixel. The side of the groove is a slope, and the angle between the slope and the bottom surface of the optical matching layer is determined by the upper limit of the refractive index of the optical adjustment layer, the refractive index of the optical matching layer, the width of the light-emitting pixel, and the size parameters of the encapsulation layer and the pixel definition layer.

11. The display panel according to claim 10, characterized in that, The display panel further includes an encapsulation layer disposed on the light-emitting pixels; wherein the encapsulation layer is a protective layer for the optical extraction structure.

12. The display panel according to claim 10, characterized in that, The display panel further includes a pixel definition layer disposed between the light-emitting pixels and the substrate, wherein a portion of the pixel definition layer is recessed to form a trapezoidal groove with a cross-sectional shape that is wider at the top and narrower at the bottom, and the pixel definition layer is adapted to define the opening of the light-emitting pixels.

13. The display panel according to claim 10, characterized in that, Its features are, The width of the light-emitting pixel ranges from 10 to 20 μm.

14. The display panel according to claim 13, characterized in that, The thickness of the pixel definition layer ranges from 1 to 3 μm, and the thickness of the encapsulation layer ranges from 2 to 3 micrometers.

15. The display panel according to claim 13, characterized in that, The projection width of the inclined surface of the pixel definition layer groove on the bottom surface ranges from 5 to 10 μm.

16. The display panel according to claim 13, characterized in that, The thickness of the optical matching layer ranges from 4 to 5 μm.

17. The display panel according to claim 13, characterized in that, The thickness of the optical adjustment layer ranges from 8 to 12 μm.

18. The display panel according to claim 9, characterized in that, The opening of the light-emitting pixel is made of an electrosensitive material, and the display panel further includes: The cathode is disposed between the pixel definition layer and the protective layer; An electric field electrode is disposed above the optical adjustment layer. The electric field electrode, in conjunction with the cathode, generates an electric field for changing the refractive index of the optical adjustment layer.

19. The display panel according to claim 18, characterized in that, The electric field electrode is disposed above the optical matching layer.

20. The display panel according to claim 18, characterized in that, The display panel further includes an anode disposed between the pixel definition layer and the substrate.

21. A display device, characterized in that, Includes the display panel as described in any one of claims 9 to 20.

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