Optical extraction structure, display panel and display device

Abstract

The invention provides an optical extraction structure, a display panel and a display device, and the structure comprises a protection layer which is suitable for being laid on a light-emitting pixel; the optical adjustment layer is arranged on the protection layer, and the refractive index of the optical adjustment layer changes along with the change of the illumination intensity or the change of the electric field; in response to the change of the refractive index of the optical adjustment layer, the refraction of the light emitted by the light-emitting pixel through the optical adjustment layer changes along with the change of the refractive index of the optical adjustment layer. By using the variability of the refractive index of the optical adjustment layer, the optical matching layer can refract or totally reflect part of light under different ambient light intensities, thereby giving consideration to both view angle improvement and efficiency improvement.

Description

Technical Field

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

[0002] With the rapid development of science and technology, display media has become an important part of people's lives. Organic light emitting diode (OLED) display media has excellent color and image quality due to its self-luminous property.

[0003] In existing OLED devices, the efficiency can be improved by adjusting the optical film layer of the device in addition to improving the luminous efficiency of the device itself. However, the optical film layer or MLA structure cannot take into account both the improvement of viewing angle and the improvement of efficiency. In other words, the light extraction structure in the current OLED device has a technical problem that the improvement of viewing angle and the improvement of efficiency cannot be taken into account at the same time. Summary of the invention

[0004] In view of this, the embodiments of the present invention are committed to providing a touch optical extraction structure, a display panel and a display device, which can ensure the optical viewing angle while improving the device efficiency, so as to solve the technical problem in the prior art that the viewing angle improvement and efficiency improvement cannot be taken into account at the same time.

[0005] In one aspect, the present invention provides an optical extraction structure, comprising: a protective layer and an optical adjustment layer. The protective layer is suitable for being laid on a light-emitting pixel. The optical adjustment layer is arranged 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 by the light-emitting pixel 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, wherein the optical matching layer is disposed in a groove opened on the optical adjustment layer and located on the periphery of the area opposite to the light-emitting pixel opening.

[0007] Preferably, at least a portion of the light emitted from the light-emitting pixel toward the optical matching layer is totally reflected by the sidewall of the groove.

[0008] Preferably, the side surface 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 inclined surface 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 is in the range of 30° to 90°.

[0011] In one embodiment, the inner side surface of the optical matching layer is perpendicular to the plane where the light-emitting pixels are 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 surface of the optical matching layer coincides with the opening boundary of the light-emitting pixel.

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

[0015] Another aspect of the present invention provides a display panel, comprising: a substrate, a light-emitting pixel and the optical extraction structure as described in the above embodiment. The light-emitting pixel is arranged on the substrate. The protective layer of the optical extraction structure is arranged on the light-emitting pixel.

[0016] In one embodiment, the optical extraction structure further includes: an optical matching layer, the optical matching layer being disposed in a groove opened on the optical adjustment layer and located on the periphery of the area opposite to the light-emitting pixel opening, the side of the groove being an inclined surface, and the angle between the inclined surface and the bottom surface of the optical matching layer being 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] Among them, θ represents the angle between the inclined surface and the bottom surface, d1 represents the width of the luminous pixel, d2 represents the projection width of the inclined surface of the groove of the pixel definition layer 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 comprises: an encapsulation layer, which is arranged on the light-emitting pixel; wherein the encapsulation layer is a protective layer of the optical extraction structure;

[0021] Preferably, the display panel further includes: a pixel definition layer, arranged between the light-emitting pixel and the substrate, wherein a partial area of ​​the pixel definition layer is concave to form a trapezoidal groove with a cross-sectional shape that is wide at the top and narrow at the bottom, and the pixel definition layer is suitable for defining the opening of the light-emitting pixel.

[0022] In one embodiment, the width of the light-emitting pixel is in the range of 10 to 20 μm.

[0023] Preferably, the thickness of the pixel definition layer is in the range of 1 to 3 μm, and the thickness of the encapsulation layer is in the range of 2 to 3 μm.

[0024] Preferably, the projection width of the inclined surface of the groove of the pixel definition layer on the bottom surface is in the range of 5 to 10 μm.

[0025] Preferably, the optical matching layer has a thickness ranging from 4 to 5 μm.

[0026] Preferably, the optical adjustment layer has a thickness ranging from 8 to 12 μm.

[0027] In one embodiment, the light-emitting pixel opening is an electrically sensitive material, and the display panel further comprises: 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 cooperates with the cathode to generate an electric field for changing the refractive index of the optical adjustment layer.

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

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

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

[0031] According to the optical extraction structure, display panel and display device of the embodiments of the present invention, an optical adjustment layer whose refractive index varies with the ambient light intensity is provided on the light-emitting pixel, and an optical matching layer whose refractive index is fixed is provided in the area outside the corresponding opening area 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 output 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. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

[0036] Figure 5 It is a schematic diagram of the local structure and dimensions of the optical extraction structure of an embodiment of the present invention.

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

[0038] Figure 7 It 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] Description of reference numerals:

[0040] 1-Substrate;

[0041] 2- anode;

[0042] 3-luminous 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 DESCRIPTION

[0050] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In the detailed description below, many specific details are proposed in order to provide a comprehensive understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention. In the drawings and the following description, at least part of the known structures and technologies are not shown in order to avoid unnecessary ambiguity of the present invention; and, for clarity, the size of some structures may be exaggerated. In addition, the features, structures or characteristics described below may be combined in one or more embodiments in any suitable manner.

[0051] In the description of the present invention, it should be noted that, unless otherwise specified, "plurality" means more than two; the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0052] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the embodiments of the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0053] In the prior art, the existing optical film layer cannot take into account both efficiency and viewing angle at the same time. Taking mobile phones as an example, the current usage scenarios of mobile phones can be roughly divided into indoor and outdoor. Indoors, the display panel does not require very high luminous brightness, and users are more concerned about its viewing angle performance. In outdoor usage scenarios, the display panel, on the contrary, requires higher forward luminescence, and the importance of viewing angle performance ranks second.

[0054] Based on the above considerations, the present invention arranges an optical extraction structure above the light-emitting pixel, including an optical adjustment layer and an optical matching layer arranged on the optical adjustment layer, wherein the optical matching layer is orthographically projected above the pixel definition layer, wherein the refractive index of the optical adjustment layer changes with the change of the ambient light intensity, and the refractive index of the optical matching layer remains fixed. The light extraction of the optical extraction structure is switched between a wide viewing angle and a positive viewing angle by utilizing the refraction and total reflection of the interface between the optical adjustment layer and the optical matching layer.

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

[0056] According to the inventive concept of one aspect 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 laid on the light-emitting pixel 3. The optical adjustment layer 5 is arranged on the protective layer, and the refractive index of the optical adjustment layer 5 changes with the change of light intensity or the change of the electric field. Among them, in response to the change of the refractive index of the optical adjustment layer 5, the refraction of the light emitted by the light-emitting pixel 3 through the optical adjustment layer 5 changes with the change of the refractive index of the optical adjustment layer 5. The light emitted to the side of the optical matching layer 6 is refracted and emitted from the light-emitting pixel 3 at a large viewing angle to increase the light emission viewing angle, or the light emitted from the light-emitting pixel 3 to the side of the optical matching layer 6 is at least partially totally reflected and emitted from the positive viewing angle of the light-emitting pixel 3 to enhance the light extraction rate at the positive viewing angle.

[0057] In this embodiment, an optical adjustment layer 5 whose refractive index varies with the ambient light intensity is provided on the light-emitting pixel 3, and the variability of the refractive index of the optical adjustment layer 5 is utilized to change the angle of refraction of light emitted by the light-emitting pixel 3 after passing through the optical adjustment layer 5, so that part of the light is refracted and emitted from a large viewing angle of the light-emitting pixel 3, thereby increasing the light output viewing angle, or part of the light is totally reflected and emitted from the front viewing angle of the light-emitting pixel 3, thereby enhancing the light extraction rate at the front viewing angle.

[0058] In one embodiment, the optical extraction structure further includes an optical matching layer 6, which is disposed in a groove on the optical adjustment layer 5 and located around the area opposite to 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, at least a portion of the light emitted from the light-emitting pixel 3 toward the optical matching layer 5 can be totally reflected by the sidewall of the groove.

[0060] In one embodiment, the optical adjustment layer 5 in the optical extraction structure is an optical regulation material, and optionally, the material characteristic is that the refractive index changes under electric field or light. Further optionally, the refractive index of the optical adjustment layer 5 gradually increases with the change of light or electric field. Generally speaking, the higher the light / electric field intensity, the greater the range of refractive index change, but there will be a material saturation refractive index, after which the refractive index will no longer increase.

[0061] In one embodiment, during the change of the ambient light intensity from low to high, the refractive index of the optical adjustment layer 5 also gradually increases from the minimum value until it reaches the saturated refractive index. In this process, the refractive index of the optical adjustment layer 5 is smaller than the refractive index of the optical matching layer 6 in the first half, and the refractive index of the optical adjustment layer 5 is larger than the refractive index of the optical matching layer 6 in the second half.

[0062] In this embodiment, if Figure 2 As shown in the figure, (a) is a working principle diagram for the case of high ambient light intensity. For example, in an 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 has the highest priority.

[0063] In order to achieve the above-mentioned purpose, the optical extraction structure provided in the embodiment of the present invention adjusts the refractive index of the optical adjustment layer 5 to be greater than the refractive index of the optical matching layer 6 under the action of ambient light or an additional electric field, and part of the light generated by the light-emitting pixel 3 is emitted from the normal viewing angle, and part of the light is obliquely incident 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 is light emitted from a denser medium to a less dense medium. When the incident angle meets certain conditions, part of the light obliquely incident on the interface between the optical adjustment layer 5 and the optical matching layer 6 is totally reflected and then emitted from the normal viewing angle of the optical extraction structure.

[0064] In this embodiment, if Figure 2 As shown in the figure, (b) is a working principle diagram for the case of low ambient light intensity, such as indoor or night usage environment, the ambient light intensity is low, and the display panel does not need too high a forward light extraction rate. In this environment, users pay more attention to the user experience. Taking the mobile phone as an example, in this usage environment, the ambient light intensity will not affect the normal display of the display panel, and the user's requirements for the use of the mobile phone are more inclined to comfort, such as chasing TV series and watching movies while doing other things. In this case, the mobile phone is generally not placed in front of the user, but mostly placed on the side of the user. At this time, the viewing angle of the extracted light of the optical extraction structure is higher, and the optical extraction structure is required to have better performance in capturing light at a large viewing angle.

[0065] In order to achieve the above-mentioned purpose, the optical extraction structure provided in the embodiment of the present invention adjusts the refractive index of the optical adjustment layer 5 to be smaller than the refractive index of the optical matching layer 6 under the action of ambient light or an additional electric field, and part of the light generated by the light-emitting pixel 3 is emitted from the normal viewing angle, and part of the light is emitted obliquely 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 small, the light is emitted from an optically sparse medium to an optically dense medium, and no total reflection will occur on the interface, only refraction will occur, and the emission angle will be further increased, that is, the effect of viewing angle scattering is further increased.

[0066] Based on the above content, it can be seen that the optical extraction structure provided in the embodiment of the present invention can be adaptively adjusted according to different usage environments, switching between the forward light extraction state and the wide-angle scattering state to meet the different needs of users in different usage environments.

[0067] In one embodiment, under the wide-angle scattering state, the refractive index of the optical adjustment layer 5 is equivalent to that of the optical matching layer 6, or the refractive index of the optical adjustment layer 5 is slightly greater than that of the optical matching layer 6, and the above effect can also be achieved. The specific effect needs to be calculated based on the specific size parameters of the components, wherein it is only necessary to ensure that the maximum incident angle of the light-emitting pixel 3 to the above interface is less than the critical angle of total reflection.

[0068] In one embodiment, the protective layer is an insulating layer disposed on the light-emitting pixel 3, which is used to electrically isolate the light-emitting pixel 3 from the optical adjustment layer 5 to prevent the 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 protective layer can be disposed separately on the light-emitting pixel 3, and the encapsulation layer 4 is 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 change of light intensity, or can change with the change of 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 (for example, liquid crystal, semiconductor particle clusters, organic / inorganic composites and multilayer materials, etc.), wherein the inorganic nonlinear optical materials include lithium niobate crystals, potassium titanyl phosphate crystals, potassium dihydrogen phosphate crystals, potassium niobate crystals, borate series materials, perovskite materials, semiconductor materials, etc., and the organic nonlinear optical materials include organic low molecular nonlinear optical materials (for example, urea and its derivatives, Schiff base compounds, azo compounds, stilbene compounds, etc.), polymer nonlinear optical materials (for example, host-guest polymers, side chain and main chain polymers, cross-linked polymers, conjugated polymers), metal organic complex nonlinear optical materials (for example, metallocene complexes, metal carbonyl complexes, etc.), etc.

[0070] In one embodiment, the host-guest type 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 a fast response speed, but also its specific performance can be adjusted through molecular design.

[0071] In one embodiment, the side chain and main chain polymers are formed by bonding chromophore molecules to the polymer main chain or side chain through covalent bonds or ionic bonds to form side chain or main chain polymer nonlinear optical materials with high orientation stability and nonlinear optical properties.

[0072] In one embodiment, the cross-linked polymer fixes the 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), polyphenylene vinylene (PPV), etc. Such polymer molecules have a high degree of delocalization and a large nonlinear optical coefficient while maintaining good transparency.

[0074] The following are some specific materials of 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 an optical extraction structure according to another embodiment of the present invention.

[0097] In one embodiment, Figure 1 and Figure 3 As shown, the inner side surface of the optical matching layer 6 is an inclined surface, wherein the angle between the inclined surface 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 the convenience of description and IE, in the present invention, the opening of the light-emitting pixel 3 is taken as a reference, and the side of the optical matching layer 6 close to the opening is defined as the inner side, and the side away from the opening is defined as the outer side.

[0099] In the present embodiment, by setting the inner side surface of the optical matching layer 6 as a bevel, the size of the interface incident angle of the light generated by the light-emitting pixel 3 on the optical adjustment layer 5 and the optical matching layer 6 can be increased, thereby improving the total reflectivity of the optical extraction structure in the forward light extraction state, that is, improving the light extraction rate at the positive viewing angle in this state; at the same time, the size of the interface incident angle of the light generated by the light-emitting pixel 3 on the optical adjustment layer 5 and the optical matching layer 6 can be increased, thereby improving the refraction angle of the optical extraction structure in the wide-view scattering state, that is, further improving the wide-view scattering degree.

[0100] In one embodiment, the light-emitting pixel 3 is disposed on the pixel definition layer 7, and the cross-sectional shape of the pixel definition layer 7 is generally a trapezoid, which is used to define the opening area of ​​the pixel. Among them, the incident angle of the light emitted from the area near the bottom corner of the trapezoid on the light-emitting pixel 3 to the inner side surface of the opposite optical matching layer 6 is the smallest. By adjusting the size of the optical extraction structure, when the optical adjustment layer 5 reaches the saturated refractive index, the light emitted from this area can be totally reflected at the interface, thereby achieving the maximum degree of light extraction at a positive viewing angle.

[0101] In one embodiment, the bottom edge of the inclined surface coincides with the opening boundary of the light-emitting pixel 3, that is, the groove on the optical adjustment layer is a through groove. In the production process, after the optical adjustment layer 5 is prepared, it is necessary to perform a groove operation on the optical adjustment layer 5, and the groove depth is controlled to achieve control of the thickness of the optical matching layer 6. The specific groove method can be photolithography or dry / wet etching, which will not be described in detail here.

[0102] In this embodiment, by increasing the thickness of the optical matching layer 6, the light emitted from the non-pixel opening area all passes through the optical matching layer 6, and is processed by the optical matching layer 6, or is caused to undergo total reflection to increase light extraction at a positive viewing angle, or is caused to undergo refracting to increase the light scattering angle, thereby increasing the light output 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°, and by selecting a matching material for the optical extraction structure, both the positive viewing angle light extraction rate and the wide viewing angle emission angle can be taken into account.

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

[0105] In one embodiment, Figure 4 As shown, the inner side 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 cross-sectional shape of the groove is a rectangular groove, which can make its preparation process simpler. Further preferably, the bottom of the optical matching layer 6 is flush with the bottom of the optical adjustment layer 5, that is, when the groove is prepared on the optical adjustment layer 5, the groove is directly opened to the bottom of the optical adjustment layer 5, so that the optical matching layer 6 covers the entire optical adjustment layer 5 in the longitudinal direction, so as to fully reflect or scatter the light at a wider angle. Further 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 upper top edge of the trapezoidal groove, which can fully reflect or refract the light emitted by the light-emitting pixel 3 to the area outside the pixel opening to the greatest extent, 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; the refractive index of the optical matching layer 6 ranges from 1.5 to 1.6.

[0108] In one embodiment, the saturation 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] Among them, I represents the irradiation intensity, Id represents the dark radiation, and t represents the 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 quality factor is calculated as follows:

[0114]

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

[0116] According to another aspect of the invention, a display panel is provided. Figure 1 , Figure 3 and Figure 4 As shown, it comprises: 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 arranged on the substrate 1. The protective layer of the optical extraction structure is arranged on the light-emitting pixel 3.

[0117] In this embodiment, the improvements of the display panel over 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 herein.

[0118] Preferably, the display panel also includes: a pixel definition layer 7, which is arranged between the luminous pixel 3 and the substrate 1, wherein a partial area of ​​the pixel definition layer 7 is concave to form a trapezoidal groove with a cross-sectional shape that is wide at the top and narrow at the bottom, and the pixel definition layer 7 is suitable for defining the opening area of ​​the luminous pixel 3.

[0119] In one embodiment, the optical extraction structure further includes an optical matching layer 6, which is disposed in a groove on the optical adjustment layer 5 and located on the periphery of the area relative to the opening of 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 included angle between the inclined surface and the bottom surface of the optical matching layer 6 satisfies the following formula.

[0121]

[0122] Among them, θ represents the angle between the inclined surface and the bottom surface, d1 represents the width of the luminous pixel, d2 represents the projection width of the inclined surface of the groove of the pixel definition layer 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 comprises an encapsulation layer 4, which is disposed on the light-emitting pixel 3; wherein the encapsulation layer 4 is a protective layer of the optical extraction structure.

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

[0125] Figure 5 It is a schematic diagram of the local structure and dimensions of the optical extraction structure of an embodiment of the present invention.

[0126] In one embodiment, Figure 3 and Figure 5 As shown, the angle between the inclined surface and the bottom surface of the optical matching layer 6 is designed in combination with the size of the optical extraction structure. Figure 5 As shown, the width of the luminous pixel 3 is d1, L1 is the light emitted from the leftmost end of the luminous pixel, passes through the upper vertex of the right end of the trapezoidal structure and irradiates the optical matching layer 6, and L2 is the light emitted by the luminous pixel 3 that is not L1 and can irradiate the inner side of the optical matching layer 6.

[0127] d2 represents the projection width of the groove slope 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. It can be concluded that:

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

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

[0130] Depend on Figure 5 The mid-angle relationship can be obtained:

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

[0132] Assuming θ5 is the critical angle of total reflection, then That is, we can get the following formula:

[0133]

[0134] Among them, the light L1 is the light with the smallest incident angle on the interface between the optical adjustment layer 5 and the optical matching layer 6, and the incident angles of other light rays that can be incident on the interface (the farthest is L2) are all greater than θ5, and all are totally reflected, so that the improvement purpose of the present invention can be achieved. Based on the above content, the size of the angle between the inner inclined surface and the bottom surface of the optical matching layer 6 can be determined by the size parameters and material parameters of the optical extraction structure and related structures.

[0135] In one embodiment, the width of the light-emitting pixel 3 is in the range of 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 μm.

[0137] Preferably, the projection width of the inclined surface of the groove 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 distance between two adjacent optical matching layers 6 is 15-30 μm.

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

[0142] In one embodiment, the opening of the light-emitting pixel 3 is an electrically sensitive material, such as Figure 6 As shown, the display panel further 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 cooperates with the cathode 8 to generate an electric field for changing 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 achieving switching between the forward light extraction state and the wide-angle scattering state.

[0144] In one embodiment, the refractive index of the optical adjustment layer 5 is changed by an external electric field, which is more controllable than adaptively changing the refractive index by ambient light intensity. The refractive index of the optical adjustment layer 5 can be manually adjusted and selected according to the user's operation instructions by changing the refractive index of the optical adjustment layer 5 by an external electric field, and the user experience is better.

[0145] Preferably, the electric field electrode 9 is disposed above the optical matching layer 6 , and the optical matching layer 6 electrically isolates the electric field electrode 9 from the optical adjustment layer 5 , thereby preventing the current from affecting the optical adjustment layer 5 .

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

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

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

[0149] In one embodiment, the display panel may be a flexible display panel or a rigid display panel. The light extraction mode of the display panel may be a bottom light extraction mode or a top light extraction mode.

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

[0151] Another aspect of the present invention provides a display device, comprising the display panel according to the above embodiment.

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

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

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

[0155] It should be noted that, for the sake of clarity, not all structures of the above-mentioned display panel and display device are described. To achieve the necessary functions of the display panel or display device, those skilled in the art may set 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical extraction structure, characterized in that: include: A protective layer, suitable for laying on the light-emitting pixels; An optical adjustment layer, disposed on the protective layer, wherein the refractive index of the optical adjustment layer changes with changes in light intensity or electric field; In response to the change of the refractive index of the optical adjustment layer, the refraction of the light emitted by the light-emitting pixel passing through the optical adjustment layer changes with the change of the refractive index of the optical adjustment layer.

2. The optical extraction structure according to claim 1, characterized in that: Also includes: An optical matching layer, the optical matching layer being disposed in a groove on the optical adjustment layer and located on the periphery of the area opposite to the light-emitting pixel opening; Preferably, at least part of the light emitted from the light-emitting pixel toward the optical matching layer is totally reflected by the sidewall of the groove; Preferably, the sidewall of the groove is a slope, wherein 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 optical extraction structure.

3. The optical extraction structure according to claim 2, characterized in that: The bottom edge of the inclined surface coincides with the opening boundary of the light-emitting pixel; Preferably, the angle between the inclined surface and the bottom surface of the optical matching layer is in the range of 30° to 90°.

4. The optical extraction structure according to claim 1, characterized in that: The inner side surface of the optical matching layer is perpendicular to the plane where the light-emitting pixels are located; Preferably, the bottom of the optical matching layer is flush with the bottom of the optical adjustment layer; Preferably, the bottom edge of the inner side surface of the optical matching layer coincides with the opening boundary of the light-emitting pixel.

5. The optical extraction structure according to claim 1, characterized in that: The refractive index of the optical adjustment layer ranges from 1.3 to 2.1; the refractive index of the optical matching layer ranges from 1.5 to 1.

6.

6. A display panel, characterized in that: include: substrate; Light-emitting pixels are arranged on the substrate; The optical extraction structure according to any one of claims 1 to 5, wherein the protective layer of the optical extraction structure is arranged on the light-emitting pixel.

7. The display panel according to claim 6, characterized in that: The optical extraction structure further includes: an optical matching layer, the optical matching layer being arranged in a groove opened on the optical adjustment layer and located on the periphery of the area opposite to the light-emitting pixel opening, the side of the groove being an inclined surface, and the angle between the inclined surface and the bottom surface of the optical matching layer being 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; Preferably, the angle between the inclined surface and the bottom surface of the optical matching layer satisfies the following formula: Wherein, 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 groove of the pixel definition layer 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; Preferably, the display panel further comprises: an encapsulation layer, which is arranged on the light-emitting pixel; wherein the encapsulation layer is a protective layer of the optical extraction structure; Preferably, the display panel further includes: a pixel definition layer, arranged between the light-emitting pixel and the substrate, wherein a partial area of ​​the pixel definition layer is concave to form a trapezoidal groove with a cross-sectional shape that is wide at the top and narrow at the bottom, and the pixel definition layer is suitable for defining the opening of the light-emitting pixel.

8. The display panel according to claim 7, characterized in that: The width of the luminous pixel ranges from 10 to 20 μm; 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 μm; Preferably, the projection width of the inclined surface of the groove of the pixel definition layer on the bottom surface ranges from 5 to 10 μm; Preferably, the thickness of the optical matching layer is in the range of 4 to 5 μm; Preferably, the optical adjustment layer has a thickness ranging from 8 to 12 μm.

9. The display panel according to claim 6, characterized in that: The light-emitting pixel opening is made of an electrically sensitive material, and the display panel further comprises: A cathode disposed between the pixel definition layer and the protective layer; An electric field electrode, disposed above the optical adjustment layer, the electric field electrode cooperates with the cathode to generate an electric field for changing the refractive index of the optical adjustment layer; Preferably, the electric field electrode is arranged above the optical matching layer; Preferably, the display panel further comprises: an anode disposed between the pixel definition layer and the substrate.

10. A display device, characterized in that: The invention comprises the display panel as claimed in any one of claims 6 to 9.

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