Top packaging structure of OLED device

Abstract

The utility model relates to the technical field of OLED (Organic Light Emitting Diode) devices, in particular to a top packaging structure of an OLED device, which comprises a plurality of interval units formed above a packaging layer and positioned in an area between two adjacent pixel units; a coating layer with a first refractive index, wherein the coating layer is formed on the upper surface of the spacing unit and wraps the spacing unit; and the light filtering layer has a second refractive index, and the light filtering layer is formed above the coating layer and the packaging layer. The liquid crystal display panel has the beneficial effects that part of light of the pixel units can be deflected from inclined incidence to vertical emergence through the coating layer and the light filtering layer with specific refractive indexes, and part of light can be vertically emergent while the reflectivity is reduced, so that the overall brightness of the panel is improved; meanwhile, a traditional color filter is replaced by the filter layer, so that the structure is simplified, and the process difficulty and the production cost are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of OLED devices, in particular to a top packaging structure of an OLED device. Background Art

[0002] In recent years, AMOLED products have been favored by more and more consumers due to their advantages such as wider color gamut, higher contrast, better color purity and foldability. However, with the development of AMOLED, the demand for higher brightness panels is getting higher and higher. Although the internal quantum efficiency of OLED devices is close to 100%, due to the optical waveguide effect and surface plasma primitive effect, when light is emitted from the inside of the OLED device to the air, the light with an incident angle greater than the critical angle is totally reflected, causing most of the generated photons to produce non-radiative coupling, resulting in an external quantum efficiency of only about 20%.

[0003] In the prior art, in order to avoid the problem of reflection of the outgoing light of the device and the reduction of the external quantum efficiency, the outgoing light is usually controlled by setting a black matrix, a filter, etc. For example, Chinese patent CN201911352402.7 discloses a color filter structure and an OLED display panel, including: a bottom layer, a color filter, a black matrix film, a protective film and a transparent conductive film, wherein the color filter contains nanoparticles; the OLED display panel includes a substrate, a TFT structure, a color blocking wall, a light-emitting layer, a pixel definition layer, a black blocking wall, a cathode layer, the color filter structure, and an encapsulation layer; wherein the height of the color filter structure is slightly lower than or equal to the height of the black blocking wall, and the color filter is used to absorb visible light of other wavelengths except the color itself, which will lead to a reduction in the reflectivity of the display screen; at the same time, the black blocking wall 6 can effectively prevent the materials in the color filter structure 8 corresponding to the pixels of different colors from crosstalking.

[0004] However, during the actual implementation process, the utility model inventor found that in this type of technical solution, although the filter can effectively remove the panel reflection, its own light transmittance is only about 50%, which will lead to a significant reduction in the overall brightness of the panel. Utility Model Content

[0005] In view of the above problems existing in the prior art, a top encapsulation structure of an OLED device is now provided.

[0006] The specific technical solutions are as follows:

[0007] A top encapsulation structure of an OLED device, the OLED device comprising a plurality of pixel units and an encapsulation layer formed above the pixel units, wherein the top encapsulation structure comprises:

[0008] A plurality of spacer units, wherein the spacer units are formed above the encapsulation layer and are located in a region between two adjacent pixel units;

[0009] A coating layer having a first refractive index, wherein the coating layer is formed on an upper surface of the spacer unit and wraps the spacer unit;

[0010] A filter layer having a second refractive index, wherein the filter layer is formed above the coating layer and the packaging layer;

[0011] The second refractive index is higher than the first refractive index.

[0012] On the other hand, the first refractive index is between 1.4 and 1.6, and the second refractive index is between 1.6 and 1.8.

[0013] On the other hand, the coating layer is formed above the spacer unit and extends from the side of the spacer unit to above the encapsulation layer;

[0014] Two adjacent groups of the coating layers are disconnected above the packaging layer to form a first opening.

[0015] On the other hand, the width of the first opening is 0-5 μm wider than the pixel width of the pixel unit.

[0016] On the other hand, the coating layer is extended on the side of the spacer unit, and its upper width is shorter than its lower width, so that the front projection of the coating layer is trapezoidal.

[0017] On the other hand, the spacing unit is a black matrix, and the spacing unit is in a cube shape.

[0018] On the other hand, the interval between adjacent spacing units is 0-10 μm wider than the pixel width of the pixel unit, and the thickness of the spacing unit is between 1-3 μm.

[0019] On the other hand, the coating layer has a thickness between 1 and 5 μm, and the filter layer has a thickness between 3 and 6 μm.

[0020] On the other hand, a planarization layer is formed above the filter layer.

[0021] On the other hand, the pixel unit and the encapsulation layer are formed above a substrate.

[0022] The above technical solution has the following advantages or beneficial effects:

[0023] In order to solve the problem in the prior art that the structure of directly reducing reflection through filters will lead to reduced panel brightness, in the present solution, a coating layer with a specific first refractive index is prepared on the spacing area for separating pixel units, and extends from the spacing area to the packaging layer, which is combined with the filter layer with a second refractive index, and can deflect part of the light of the pixel unit from oblique incidence to vertical emission, thereby reducing the reflectivity and allowing part of the light to be emitted vertically, thereby improving the overall brightness of the panel; and, by replacing the traditional color filter with a filter layer that completely covers the spacing unit and the coating layer, the processes of setting up corresponding masks and preparing color filters can be omitted in the preparation process, so that the process difficulty and production cost are greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The embodiments of the present invention will be described more fully with reference to the attached drawings, which are however only used for illustration and description and are not intended to limit the scope of the present invention.

[0025] Figure 1 It is an overall schematic diagram of an embodiment of the utility model;

[0026] Figure 2 This is a schematic diagram of the first optical path in the embodiment of the utility model;

[0027] Figure 3 This is a schematic diagram of the second optical path in the embodiment of the utility model. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0030] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0031] The utility model includes:

[0032] A top encapsulation structure of an OLED device, the OLED device comprising a plurality of pixel units 1 and an encapsulation layer 2 formed above the pixel units 1, wherein the top encapsulation structure comprises:

[0033] A plurality of spacer units 3, wherein the spacer units 3 are formed above the encapsulation layer 2 and are located in a region between two adjacent pixel units 1;

[0034] A coating layer 4 having a first refractive index, wherein the coating layer 4 is formed on an upper surface of the spacer unit 3 and wraps the spacer unit 3;

[0035] A filter layer 5 having a second refractive index, wherein the filter layer 5 is formed above the coating layer 4 and the packaging layer 2;

[0036] The second refractive index is higher than the first refractive index.

[0037] Specifically, in view of the problem in the prior art that the technical means of reducing the reflectivity by only absorbing the obliquely incident light through the color filter will lead to a reduction in the overall panel brightness, in this embodiment, after the pixel unit 1 and the encapsulation layer 2 are prepared in sequence, a spacing unit 3 is formed above the encapsulation layer 2 to divide the pixel units 1 of different colors and avoid light crosstalk of different colors. At this time, since the height of the spacing unit 3 is higher than the encapsulation layer 2 and is disconnected at the position above the pixel unit 1, the spacing unit 3 itself forms a plurality of boss-like structures on the encapsulation layer 2. On this basis, by preparing the coating layer 4, and controlling the material of the coating layer 4 to have a first refractive index, and making the coating layer 4 completely wrap the spacing unit 3, the outgoing light originally obliquely emitted from the encapsulation layer 2 and pointing to the spacing unit 3 will be refracted in a specific direction after entering the coating layer 4. On this basis, a filter layer 5 with a second refractive index is prepared on the upper surface of the encapsulation layer 2 and the coating layer 3. Through the above-mentioned structural setting and the adjustment of the refractive index of each layer, it is achieved that the part of the obliquely emitted light is refracted twice through the filter layer 5-coating layer 4 after the encapsulation layer 2, converted into vertical emission, and then emitted through the filter layer 5, thereby increasing the total amount of vertically emitted light and improving the panel brightness.

[0038] Furthermore, in the prior art, it is usually necessary to prepare a color filter corresponding to the pixel color above the pixel unit 1, which results in the need to set different masks and align the openings of the spacing unit 3 to prepare the color filter during the preparation process. The above process flow is relatively complicated, and it is necessary to set three masks in sequence, resulting in the overall process difficulty and increased costs. In this regard, in this embodiment, after the above-mentioned structural setting, a filter layer 5 with a second refractive index can be used to completely cover the coating layer 3 above the spacing unit 3 and the encapsulation layer 2, and the original color filter is eliminated. Since the structure is simplified relative to the traditional color filter structure, only one mask needs to be set during the production process, and multiple alignments are not required, which simplifies the production process and reduces the production difficulty and cost.

[0039] During the implementation process, the above-mentioned top encapsulation structure is mainly prepared above the OLED device as the upper encapsulation structure of the OLED device. Generally speaking, during the preparation process of the OLED device, various structures such as cathode or anode, pixel unit 1, anode or cathode, auxiliary connection layer and filter need to be prepared on the substrate 6. After the preparation is completed, the encapsulation layer 2 is prepared above the above-mentioned device structure. The top encapsulation structure involved in this scheme mainly prepares the spacing unit 3, coating layer 4, etc. above the encapsulation layer 2. However, in some embodiments, the side wall between the pixel units 1 may also be directly used as the spacing unit 3, and the coating layer 4 is prepared above it. After completing the preparation of the above-mentioned top encapsulation structure, other layers may also be prepared on it according to product requirements.

[0040] In one embodiment, the first refractive index is between 1.4 and 1.6, and the second refractive index is between 1.6 and 1.8.

[0041] Specifically, in order to achieve a better refractive effect, the inventors determined the combination of the above-mentioned refractive indices after repeated experiments, that is, the second refractive index of the filter layer 5 is controlled to be between 1.6-1.8, and the first refractive index of the coating layer 4 is controlled to be between 1.4-1.6, so that the inclined light directed to the spacing unit 3 can be effectively converted into vertical light emission.

[0042] As an optional embodiment, in order to achieve the above-mentioned specific refractive index, the composition of the filter layer 5 can be controlled to contain part or all of ZrO2, TiO2, and HfO2 nanoparticles, and color dyes or pigments can be added or not to optimize the panel light spectrum, improve the luminous effect, and control its transmittance between 50% and 80% to achieve a better transmission effect.

[0043] In one embodiment, the coating layer 4 is formed above the spacer unit 3 and extends from the side of the spacer unit 3 to above the encapsulation layer 5;

[0044] Two adjacent groups of coating layers 4 are disconnected above the encapsulation layer 5 to form a first opening.

[0045] Specifically, in order to achieve a better effect of taking out inclined light, in the present embodiment, in the process of preparing the coating layer 4, the coating layer 4 has a certain thickness above the spacer unit 3, and extends along the side of the spacer unit 3 to above the encapsulation layer 5, thereby achieving complete covering of the spacer unit 3 to facilitate receiving the inclined light. At the same time, it extends above the encapsulation layer 5 and is controlled to be disconnected above the encapsulation layer 5, that is, corresponding to the position of the pixel unit 1 to form a first opening. While achieving the extraction of the inclined light, it avoids the problem of excessive vertical light in the pixel unit 1 entering the coating layer 4 and affecting normal light transmission.

[0046] In one embodiment, the coating layer 4 is extended on the side of the spacer unit 3 and its upper width is shorter than its lower width, so that the front projection of the coating layer 4 is trapezoidal, and the inclination angle of the extension of the coating layer 4 relative to the packaging layer is greater than 65 degrees.

[0047] Specifically, in order to achieve effective vertical deflection of light, in this embodiment, specific improvements are made to the shape of the coating layer 4. Specifically, the extension portion of the side of the coating layer 4 is processed to form an inclined surface, and the inclination angle between the inclined surface and the encapsulation layer in the horizontal direction is controlled to be greater than 65 degrees, thereby achieving effective reception of light with an angle of less than 50 degrees with the horizontal plane, and effectively deflecting the light based on the above-mentioned refractive index.

[0048] In the implementation process, the coating layer 4 is mainly realized by film patterning technology, and the specific implementation method can be photolithography, inkjet, etc. For example, in one embodiment, after the spacer unit 3 is prepared in advance, a continuous pre-coating layer can be formed on the spacer unit 3 and the encapsulation layer 2 by chemical vapor deposition or evaporation, and then, a certain amount of the pre-coating layer is removed in sequence at different positions by photolithography, so as to form a first opening, and the extension portion is processed to have a specific inclination angle.

[0049] In one embodiment, the width of the first opening is 0-5 μm wider than the pixel width of the pixel unit.

[0050] Specifically, in order to reduce the influence of the material of the coating layer 4 itself on the brightness of the outgoing light, in this embodiment, on the basis of processing the first opening at the position of the coating layer 4 above the pixel unit 3, the width of the first opening is further adjusted to 0-5μm outside the pixel width of the pixel unit according to the pixel width, thereby reducing the influence on the outgoing light and achieving the control of the amount of light entering the coating layer 4, thereby achieving a better improvement in the overall panel brightness.

[0051] In one embodiment, the spacing unit 3 is a black matrix, and the spacing unit 3 is in a cube shape.

[0052] Specifically, in order to reduce the reflectivity in the panel, in this embodiment, the spacing unit 3 is set as a black matrix, which absorbs light with too large an angle that may cause crosstalk, thereby avoiding the problem of reflection in the light generating device affecting light output.

[0053] In one embodiment, the interval between adjacent spacing units 3 is 0-10 μm wider than the pixel width of the pixel unit 1 , and the thickness of the spacing unit 3 is between 1-3 μm.

[0054] The thickness of the coating layer 4 is between 1 and 5 μm, and the thickness of the filter layer 5 is between 3 and 6 μm.

[0055] Specifically, in order to achieve a better display effect, in this embodiment, the inventors analyzed the optical path of the outgoing light of the pixel unit 1 and found that Figure 2 As shown, when there is inclined outgoing light in the pixel unit 1, the overall height of the coating layer 4 will significantly affect the amount of outgoing light available in the pixel unit 1. For example, Figure 2 It can be seen from FIG. 1 that when the tilt angle of the light is fixed, the light source that the trapezoidal coating layer having the first thickness can receive is the S1 width area in the pixel unit 1; and Figure 3 It can be seen that, under the condition that the inclination angle of the light remains unchanged, by increasing the thickness of the trapezoidal coating layer to the second thickness, the source of light that can be received is significantly increased from the S1 width area to the S2 width area, thereby improving the light extraction efficiency and increasing the panel brightness.

[0056] On this basis, in order to achieve a better device flattening effect, in this embodiment, after the thickness of the coating layer 4 and the width of the first opening are determined through experiments, the interval and thickness between the spacing units 3 are further determined according to these two parameters, that is, the extension of the coating layer 4 has a sufficient thickness to deflect the light, and the first opening meets the light extraction requirements, the feasible interval and height of the spacing unit 3. Then the thickness of the filter layer 5 is controlled so that the overall thickness of the filter layer 5 matches the spacing unit 3 and the coating layer 4. Thus, the corresponding device flattening effect is achieved.

[0057] In one embodiment, a planarization layer 7 is formed on the filter layer 5 .

[0058] Specifically, in order to achieve a better device platform effect, in this embodiment, a planarization layer 7 is further prepared above the filter layer 5. This layer is mainly used to planarize the device, but in some embodiments, it can also be replaced by a polarizer or other optical structures.

[0059] The above are only preferred embodiments of the present invention, and do not limit the implementation mode and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A top encapsulation structure of an OLED device, the OLED device comprising a plurality of pixel units and an encapsulation layer formed above the pixel units, characterized in that: The top packaging structure comprises: A plurality of spacer units, wherein the spacer units are formed above the encapsulation layer and are located in a region between two adjacent pixel units; A coating layer having a first refractive index, wherein the coating layer is formed on an upper surface of the spacer unit and wraps the spacer unit; A filter layer having a second refractive index, wherein the filter layer is formed above the coating layer and the packaging layer; The second refractive index is higher than the first refractive index.

2. The top encapsulation structure according to claim 1, characterized in that: The first refractive index is between 1.4 and 1.6, and the second refractive index is between 1.6 and 1.

8.

3. The top packaging structure according to claim 1, characterized in that: The coating layer is formed above the spacer unit and extends from the side of the spacer unit to above the encapsulation layer; Two adjacent groups of the coating layers are disconnected above the packaging layer to form a first opening.

4. The top packaging structure according to claim 3, characterized in that: The width of the first opening is 0-5 μm wider than the pixel width of the pixel unit.

5. The top encapsulation structure according to claim 3, characterized in that: The coating layer is extended on the side of the spacer unit, and its upper width is shorter than its lower width, so that the front projection of the coating layer is trapezoidal.

6. The top packaging structure according to claim 5, characterized in that: The extending portion of the coating layer has an inclination angle greater than 65 degrees relative to the encapsulation layer.

7. The top encapsulation structure according to claim 1, characterized in that: The spacing unit is a black matrix and is in a cube shape.

8. The top encapsulation structure according to claim 1, characterized in that: The interval between adjacent spacing units is 0-10 μm larger than the pixel width of the pixel unit, and the thickness of the spacing unit is between 1-3 μm.

9. The top package structure according to claim 1, characterized in that: The coating layer has a thickness of 1-5 μm, and the filter layer has a thickness of 3-6 μm.

10. The top encapsulation structure according to claim 1, characterized in that: A planarization layer is formed on the filter layer.

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