Display panel and preparation method thereof

Abstract

The invention provides a display panel and a preparation method thereof. The display panel includes a light emitting layer, a first refractive layer, and a second refractive layer. The first refraction layer is arranged on one side of the light-emitting layer and comprises at least one micro-lens, and the width of the end, close to the light-emitting layer, of the micro-lens and the width of the end, away from the light-emitting layer, of the micro-lens are smaller than the width of the middle position of the micro-lens. The second refraction layer is arranged on the side, away from the light-emitting layer, of the first refraction layer and covers the micro lenses. The micro lens in the first refraction layer is designed to be of a structure with the upper end and the lower end being narrow and the middle being wide, so that the anti-interference performance of the micro lens on structure morphology fluctuation is improved, and therefore the problems that due to process fluctuation, the technical performance of the micro lens does not reach the standard, and the effect difference of the micro lens between different panels is large are solved.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a display panel and a method for preparing the same. Background Art

[0002] Improving the light extraction efficiency of organic light-emitting diodes (OLEDs) is conducive to further reducing the power consumption of the whole device and extending the life of the screen. In addition to improving efficiency through iterative upgrades of materials, adjusting the light path of OLEDs to improve light extraction efficiency is another feasible direction to reduce power consumption. MLA (Micro Lensarray) technology refracts or reflects large-angle light to the normal light output angle, thereby enhancing the normal light output, which is one of the effective means to improve the light extraction efficiency of OLEDs.

[0003] However, in current MLA products, due to process limitations, the MLA structure inevitably has structural fluctuations and low uniformity, which leads to differences in effects between different display panels and a high defective rate of finished products. Summary of the invention

[0004] The object of the present invention is to provide a display panel and a method for preparing the same, so as to solve the problem in the prior art that the MLA structure has fluctuations and low uniformity, resulting in differences in effects between different display panels.

[0005] To achieve the above object, the present invention provides a display panel, which includes a light-emitting layer, a first refractive layer and a second refractive layer. The first refractive layer is arranged on one side of the light-emitting layer, and includes at least one microlens. In a direction perpendicular to the light-emitting layer, the width of the microlens at one end close to the light-emitting layer and at one end away from the light-emitting layer is smaller than the width at the middle position of the microlens. The second refractive layer is arranged on the side of the first refractive layer away from the light-emitting layer, and covers the microlens.

[0006] Furthermore, the display panel further comprises an isolation layer disposed between the microlens and the second refractive layer, and preferably, the refractive index of the isolation layer is greater than the refractive index of the first refractive layer and less than the refractive index of the second refractive layer. Preferably, the material of the isolation layer comprises at least one of an organic material or an inorganic material.

[0007] Further, the microlens includes a bottom surface and a top surface. The bottom surface is located on a side of the microlens close to the light-emitting layer. The top surface is parallel to the bottom surface and is located on a side of the microlens away from the light-emitting layer. The width of the bottom surface is greater than or equal to the width of the top surface. Preferably, the cross-section of the microlens in the stacking direction of the display panel is a hexagon.

[0008] Furthermore, the light-emitting layer includes a plurality of light-emitting units, each of which includes at least one light-emitting device. The orthographic projection of the microlens on the light-emitting layer does not overlap with the orthographic projection of the light-emitting unit on the light-emitting layer. Preferably, the horizontal distance between the bottom surface and the adjacent light-emitting unit is less than or equal to the horizontal distance between the top surface and the adjacent light-emitting unit.

[0009] Further, the microlens includes a base portion and a raised portion. The base portion is arranged on one side of the light-emitting layer. The raised portion is arranged on a side of the base portion away from the light-emitting layer. The thickness of the base portion is less than or equal to the thickness of the raised portion. Preferably, the thickness of the base portion is 30%-50% of the thickness of the microlens. Preferably, the thickness of the raised portion is 50%-70% of the thickness of the microlens. Preferably, the thickness of the microlens is 2-4 microns.

[0010] Further, the refractive index of the first refractive layer is less than the refractive index of the second refractive layer. Preferably, the refractive index of the first refractive layer is less than 1.6. Preferably, the refractive index of the second refractive layer is greater than or equal to 1.6.

[0011] Furthermore, the display panel further comprises a transition layer disposed between the light emitting layer and the first refractive layer. Preferably, the material of the transition layer comprises at least one of an organic material and an inorganic material.

[0012] The present invention also provides a method for preparing a display panel, which includes the following steps: forming a first refractive layer on one side of a light-emitting layer; forming a microlens in the first refractive layer through a patterning process, wherein the width of the microlens at one end close to the light-emitting layer and at one end away from the light-emitting layer is smaller than the width at the middle position of the microlens; and forming a second refractive layer on the side of the first refractive layer away from the light-emitting layer.

[0013] Furthermore, the method for preparing the display panel further comprises: forming an isolation layer on the surface of the microlens. Preferably, the step of forming the isolation layer on the surface of the microlens comprises: depositing the material of the isolation layer on the surface of the lens layer by a chemical vapor deposition process, an atomic layer deposition process or a sol-gel process. Preferably, the material of the isolation layer comprises one of an organic material or an inorganic material.

[0014] Furthermore, the patterning process used in the step of forming the microlens in the first refractive layer includes at least one of a dry etching process, a wet etching process or a photolithography process. Preferably, the photolithography process is a digital maskless photolithography process.

[0015] Advantages of the present invention: A display panel and a preparation method thereof of the present invention improves the anti-interference ability of the microlens to structural morphology fluctuations by setting the microlens in the first refractive layer to a structure with smaller widths at both ends and larger width in the middle in the stacking direction of the display panel, thereby solving the problem of substandard technical performance of the microlens caused by process fluctuations and large differences in the effects of the microlenses between different panels. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 is a schematic diagram of a layered structure of a display panel in an embodiment of the present invention;

[0018] Figure 2 is an enlarged schematic diagram of the cross-sectional structure of a microlens in an embodiment of the present invention;

[0019] Figure 3 is a schematic flow chart of a method for preparing a display panel according to an embodiment of the present invention;

[0020] Figure 4 It is a schematic diagram of the layered structure of the display panel after the transition layer is formed in the embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of the layered structure of the display panel after the first refractive layer is formed in an embodiment of the present invention;

[0022] Figure 6 is a schematic diagram of the layered structure of the display panel after the first refractive layer is patterned for the first time in an embodiment of the present invention;

[0023] Figure 7 is a schematic diagram of the layered structure of the display panel after the first refractive layer is patterned for the second time in an embodiment of the present invention;

[0024] Figure 8 Schematic diagram of the layered structure of the display panel after the isolation layer is formed in an embodiment of the present invention.

[0025] The components in the figure are shown as follows:

[0026] Display panel 1; Light emitting layer 10;

[0027] Light-emitting unit 11; Transition layer 20;

[0028] A first refractive layer 30; A microlens 31;

[0029] Base portion 311; Raised portion 312;

[0030] A bottom surface 313 of the microlens; A top surface 314 of the microlens;

[0031] The isolation layer 40; and the second refractive layer 50. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are described below with reference to the drawings in the specification to prove that the present invention can be implemented. The embodiments of the invention can fully introduce the present invention to those skilled in the art, making its technical content clearer and easier to understand. The present invention can be embodied through many different forms of embodiments of the invention, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0033] In the drawings, components with the same structure are indicated by the same numerical reference numerals, and components with similar structures or functions are indicated by similar numerical reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thickness of the components is appropriately exaggerated in some places in the drawings.

[0034] In addition, the following descriptions of the various embodiments of the invention are made with reference to the attached diagrams to illustrate specific embodiments of the invention that the present invention can be implemented with. The directional terms mentioned in the present invention, such as "upper", "lower", "front", "back", "left", "right", "inner", "outer", "side", etc., are only with reference to the directions of the attached drawings. Therefore, the directional terms used are for better and clearer description and understanding of the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0035] When some components are described as being "on" another component, the component may be directly placed on the other component; there may also be an intermediate component on which the component is placed, and the intermediate component is placed on the other component. When a component is described as being "mounted on" or "connected to" another component, the two may be understood to be directly "mounted on" or "connected", or one component may be indirectly "mounted on" or "connected to" another component via an intermediate component.

[0036] In related display technologies, MLA (Micro Lens array) technology is used to improve the light utilization of the display panel and enhance the front-view brightness of the display panel. However, the final efficiency improvement of the MLA product is highly correlated with its structure. In the entire display panel, slight differences in exposure energy, etching solution concentration, etc. will inevitably lead to fluctuations in the MLA structure, such as the angle of the Taper angle, which can easily lead to unstable performance between different display panels in the same production batch, resulting in a large number of defective products.

[0037] In order to solve the above technical problems, an embodiment of the present invention provides a display panel 1, such as Figure 1 As shown, the display panel 1 includes a light emitting layer 10 , a transition layer 20 , a first refractive layer 30 and a second refractive layer 50 .

[0038] The light-emitting layer 10 includes a plurality of light-emitting units 11, each of which includes at least one light-emitting device, which may be one of light-emitting devices such as an OLED (Organic Light Emitting Diode) device, a QLED (Quantum Dot Light Emitting Diodes) device, a Mimi-LED (sub-millimeter light-emitting diode) device, and a Micro-LED (micro light-emitting diode) device. The light-emitting device is used to convert electrical energy into light energy, thereby providing a light source for the display panel 1, so that the display panel 1 can display images.

[0039] The transition layer 20 is disposed on the light-emitting surface of the light-emitting layer 10, and its material includes one or more of organic materials and inorganic materials. Specifically, the transition layer 20 can be an encapsulation functional layer or an insulating functional layer for protecting the light-emitting layer 10, and can be prepared by a preparation process such as a TFE (Thin Film Encapsulation) process, a deposition process, and a coating process.

[0040] The first refractive layer 30 is disposed on a side of the transition layer 20 away from the light emitting layer 10, and includes at least one microlens 31, and the orthographic projection of the microlens 31 on the transition layer 20 does not overlap with the orthographic projection of the light emitting unit 11 on the transition layer 20. In the embodiment of the present invention, the microlens 31 is a single-layer film layer, which can be formed by opening a through hole corresponding to the light emitting unit 11 in the first refractive layer 30. In other embodiments of the present invention, the first refractive layer 30 may include a plurality of microlenses 31, and the plurality of microlenses 31 may be arranged around the light emitting unit 11.

[0041] like Figure 2As shown, the microlens 31 has a bottom surface 313 and a top surface 314. The bottom surface 313 is located on the side of the microlens 31 close to the light-emitting layer 10 and in contact with the transition layer 20. The top surface 314 is located on the side of the microlens 31 away from the light-emitting layer 10 and parallel to the bottom surface 313. The width of the bottom surface 313 and the width of the top surface 314 of the microlens 31 are smaller than the width of the middle position of the microlens 31, that is, the width of the end of the microlens 31 close to the light-emitting layer 10 and the end away from the light-emitting layer 10 are smaller than the width of the middle position. In this structure, the taper angle of the microlens 31 (that is, the angle between the bottom surface 313 of the microlens 31 and the adjacent side surface) is large, and it has good anti-interference performance against fluctuations in the structural morphology, which can effectively solve the problem of substandard performance of the microlens 31 caused by process fluctuations and large differences between different display panels 1 in the same batch. Further, the horizontal distance L1 between the bottom surface 313 of the microlens 31 and the adjacent light-emitting unit 11 is less than or equal to the horizontal distance L2 between the top surface 314 and the adjacent light-emitting unit 11, that is, the width of the bottom surface 313 of the microlens 31 is greater than or equal to the width of the top surface 314, thereby increasing the contact area between the microlens 31 and the transition layer 20, thereby improving the structural stability of the microlens 31. Preferably, the cross section of the microlens 31 in the stacking direction of the display panel 1 is hexagonal.

[0042] Specifically, Figure 2As shown, the microlens 31 includes a base portion 311 and a raised portion 312. The base portion 311 is arranged on the surface of the transition layer 20 away from the light-emitting layer 10, and the surface away from the raised portion 312 is the bottom surface 313 of the microlens 31, and its cross section in the stacking direction of the display panel 1 is a shape that is wide at the top and narrow at the bottom. The raised portion 312 is arranged on the side of the base portion 311 away from the light-emitting layer 10, and the surface away from the base portion 311 is the top surface 314 of the microlens 31, and its cross section in the stacking direction of the display panel 1 is a shape that is narrow at the top and wide at the bottom. Preferably, the cross section of the base portion 311 is an inverted trapezoid, and the cross section of the raised portion 312 is a regular trapezoid. The thickness h1 of the base portion 311 is less than or equal to the thickness h2 of the raised portion 312. Compared with the raised portion 312, the larger bottom width and smaller thickness of the base portion 311 can increase the overall structural stability of the microlens 31, reduce the difficulty of patterning the first refractive layer 30, and reduce the influence of the structural change of the microlens 31 on the focusing effect of the MLA technology. Preferably, the thickness h1 of the base portion 311 is 30%-50% of the thickness h of the microlens 31, and the thickness h2 of the raised portion 312 is 50%-70% of the thickness h of the microlens 31; for example, the thickness h1 of the base portion 311 is 35% or 45% of the thickness h of the microlens 31, and the thickness h2 of the raised portion 312 is 55% or 65% of the thickness h of the microlens 31. Furthermore, the thickness h of the microlens 31 is 2-4 μm; for example, the thickness h of the microlens 31 can be 2.5 μm or 3 μm, the thickness h1 of the base portion 311 can be 1.25 μm or 1.5 μm, and the thickness h2 of the raised portion 312 can be 1.25 μm or 2.1 μm.

[0043] The second refractive layer 50 is disposed on a side of the first refractive layer 30 away from the light emitting layer 10 and covers the microlens 31. In the embodiment of the present invention, the second refractive layer 50 fills the through hole in the first refractive layer 30 and covers the surface of the microlens 31 away from the light emitting layer 10. In another embodiment of the present invention having a plurality of microlenses 31, the second refractive layer 50 fills the gap between adjacent microlenses 31 and wraps the exposed surface of each microlens 31.

[0044] The first refraction layer 30 and the second refraction layer 50 are both made of organic or inorganic materials with high light transmittance (light transmittance greater than 80%). At least part of the light emitted by the light emitting unit 11 will pass through the interface between the first refraction layer 30 and the second refraction layer 50, and because the refractive index of the first refraction layer 30 is less than the refractive index of the second refraction layer 50, refraction and total reflection will occur at the interface between the first refraction layer 30 and the second refraction layer 50, thereby reducing the exit angle of the large-angle light emitted by the light emitting unit 11, adjusting the large-angle light to the normal viewing angle parallel to the stacking direction of the display panel 1, thereby achieving a focusing effect, reducing light loss and improving the normal viewing brightness of the display panel 1. Further, the refractive index of the first refraction layer 30 is less than 1.6, and the refractive index of the second refraction layer 50 is greater than or equal to 1.6; for example, the refractive index of the first refraction layer 30 is 1.5 or 1.55, and the refractive index of the second refraction layer 50 is 1.7 or 2.0.

[0045] Furthermore, the display panel 1 further includes an isolation layer 40. Figure 1 As shown, the isolation layer 40 is disposed between the microlens 31 and the second refractive layer 50, and can be an organic material or an inorganic material, such as silicon oxide, oxynitride, aluminum oxide, etc. Specifically, the isolation layer 40 is made of a material that is immiscible with both the first refractive layer 30 and the second refractive layer 50. For example, when the first refractive layer 30 and the second refractive layer 50 are both inorganic materials, the isolation layer 40 can be an organic layer; when the first refractive layer 30 and the second refractive layer 50 are both organic materials, the isolation layer 40 can be an inorganic material. The isolation layer 40 is used to separate the first refractive layer 30 and the second refractive layer 50, and prevent the first refractive layer 30 and the second refractive layer 50 from being miscible due to the same or similar materials, thereby protecting the structure of the microlens 31 in the first refractive layer 30. Furthermore, the refractive index of the isolation layer 40 is greater than the refractive index of the first refractive layer 30, and less than the refractive index of the second refractive layer 50.

[0046] The present invention also provides a method for preparing a display panel 1, which is used to prepare Figure 1 The display panel 1 shown in FIG. 1 is prepared by the following process: Figure 3 As shown, it includes steps S10-S50.

[0047] Step S10) forming a transition layer 20 on one side of the light emitting layer 10:

[0048] One or more organic materials and inorganic materials are prepared on the light-emitting surface of the light-emitting layer 10 by a TFE process, a deposition process or a coating process to form a Figure 4 The transition layer 20 is shown in FIG.

[0049] Step S20) forming a first refraction layer 30 on one side of the light emitting layer 10:

[0050] A layer of a low refractive index material with a refractive index lower than 1.6 is coated on a layer of the transition layer 20 away from the light emitting layer 10 by a coating process or a deposition process to form a Figure 5 The first refractive layer 30 is shown in FIG.

[0051] Step S30) forming a microlens 31 in the first refractive layer 30 by a patterning process:

[0052] The first refractive layer 30 is patterned for the first time by a dry etching process, a wet etching process or a photolithography process to form Figure 6 The cross section of the microlens 31 is a positive trapezoidal structure as shown in FIG; the first refractive layer 30 is patterned again by a dry etching process, a wet etching process or a photolithography process to reduce the width of the bottom surface 313 of the microlens 31 with a positive trapezoidal cross section, thereby forming a Figure 7 The cross section of the microlens 31 shown in FIG. 1 is a hexagonal structure.

[0053] In another embodiment of the present invention, the microlens 31 with a hexagonal cross-section may be formed in the first refractive layer 30 by only one photolithography process. Preferably, the photolithography process is digital maskless lithography.

[0054] Step S40) forming an isolation layer 40 on the surface of the microlens 31:

[0055] A layer of inorganic material or organic material is deposited on the surface of the microlens 31 by a deposition process or a coating process, and the material covering the surface of the transition layer 20 is removed by a patterning process, thereby forming a Figure 8 The isolation layer 40 shown in FIG. Preferably, the deposition process used in this step can be one of the processes such as chemical vapor deposition process (CVD), atomic layer deposition process (ALD), sol-gel process, etc.

[0056] Step S50) forming a second refractive layer 50 on a side of the first refractive layer 30 away from the light emitting layer 10:

[0057] A layer of high refractive index material with a refractive index greater than or equal to 1.6 is coated on the side of the first refractive layer 30 away from the light emitting layer 10 by inkjet printing, coating or deposition, and the high refractive index material is filled into the through holes or gaps in the first refractive layer 30 to form a Figure 1 The second refractive layer 50 is shown in FIG.

[0058] In the embodiment of the present invention, the microlens in the first refractive layer is improved to have a structure with a smaller width at both ends and a larger width in the middle in the stacking direction of the display panel to improve the anti-interference of the microlens to the fluctuation of the structural morphology, thereby solving the problem that the technical performance of the microlens does not meet the standard and the effect of the microlens between different display panels is greatly different due to process fluctuations, thereby promoting the uniformity and stability of the performance between different display panels in the same batch, and reducing the defective rate of the production line. At the same time, in the embodiment of the present invention, an isolation layer is also provided to protect the structure of the microlens in the first refractive layer to prevent the first refractive layer and the second refractive layer from having a mutual dissolution problem due to the similarity of materials.

[0059] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A display panel, characterized in that: include: Luminescent layer; A first refractive layer, disposed on one side of the light-emitting layer, comprising at least one microlens; In a direction perpendicular to the light-emitting layer, the width of the microlens at one end close to the light-emitting layer and at one end away from the light-emitting layer is smaller than the width at the middle position of the microlens; The second refractive layer is arranged on a side of the first refractive layer away from the light emitting layer and covers the microlens.

2. The display panel according to claim 1, wherein: Also includes: an isolation layer, disposed between the microlens and the second refractive layer; Preferably, the refractive index of the isolation layer is greater than the refractive index of the first refractive layer and less than the refractive index of the second refractive layer; Preferably, the material of the isolation layer includes at least one of an organic material or an inorganic material.

3. The display panel according to claim 1, wherein: The microlens comprises: a bottom surface, located on a side of the microlens close to the light-emitting layer; a top surface, parallel to the bottom surface and located on a side of the microlens away from the light-emitting layer; The width of the bottom surface is greater than or equal to the width of the top surface; Preferably, the cross section of the microlens in the stacking direction of the display panel is hexagonal.

4. The display panel according to claim 3, wherein: The light-emitting layer includes a plurality of light-emitting units, each of which includes at least one light-emitting device; The orthographic projection of the microlens on the light-emitting layer does not overlap with the orthographic projection of the light-emitting unit on the light-emitting layer; Preferably, a horizontal distance between the bottom surface and an adjacent light emitting unit is less than or equal to a horizontal distance between the top surface and an adjacent light emitting unit.

5. The display panel according to claim 1, wherein: The microlens comprises: A base portion, disposed on one side of the light-emitting layer; A raised portion, arranged on a side of the base away from the light-emitting layer; The thickness of the base portion is less than or equal to the thickness of the raised portion; Preferably, the thickness of the base portion is 30%-50% of the thickness of the microlens; Preferably, the thickness of the raised portion is 50%-70% of the thickness of the microlens; Preferably, the thickness of the microlens is 2-4 microns.

6. The display panel according to claim 1, wherein: The refractive index of the first refractive layer is smaller than the refractive index of the second refractive layer; Preferably, the refractive index of the first refractive layer is less than 1.6; Preferably, the refractive index of the second refractive layer is greater than or equal to 1.

6.

7. The display panel according to claim 1, wherein: Also includes: A transition layer, disposed between the light-emitting layer and the first refractive layer; Preferably, the material of the transition layer includes at least one of an organic material and an inorganic material.

8. A method for preparing a display panel, characterized in that: include: forming a first refractive layer on one side of the light emitting layer; forming a microlens in the first refractive layer by a patterning process, wherein the width of the microlens at one end close to the light-emitting layer and at one end away from the light-emitting layer is smaller than the width at the middle of the microlens; A second refractive layer is formed on a side of the first refractive layer away from the light emitting layer.

9. The method for preparing a display panel according to claim 8, wherein: Also includes: forming an isolation layer on a surface of the microlens; Preferably, the step of forming the isolation layer on the surface of the microlens comprises: depositing the material of the isolation layer on the surface of the lens layer by chemical vapor deposition process, atomic layer deposition process or sol-gel process; Preferably, the material of the isolation layer includes one of an organic material and an inorganic material.

10. The method for preparing a display panel according to claim 8, wherein: The patterning process used in the step of forming the microlens in the first refractive layer includes at least one of a dry etching process, a wet etching process or a photolithography process; Preferably, the photolithography process is a digital maskless photolithography process.

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