Organic light emitting diode device and preparation method thereof, display panel, and display device

Abstract

The present invention provides an organic light emitting diode device and a preparation method thereof, a display panel, and a display device, which belong to the field of display technology and can solve the problems that the existing OLED with a low aperture ratio has a short lifespan and the OLED product with a high aperture ratio has a low yield. The light emitting unit in the organic light emitting diode device of the present invention is a non-planar structure, and the surface area of ​​its light emitting surface is larger than its positive projection area on the substrate, which is equivalent to increasing the area of ​​its light emitting area while keeping the pixel aperture ratio of the OLED display area unchanged, that is, ensuring the yield of the OLED product, and at the same time reducing the current density of the light emitting unit, thereby significantly improving the lifespan of the OLED. The organic light emitting diode device of the present invention is suitable for various display devices.

Description

Technical Field

[0001] The present invention belongs to the field of display technology, and in particular relates to an organic light emitting diode device and a preparation method thereof, a display panel, and a display device. Background Art

[0002] Organic Light Emitting Diode (OLED) devices are devices that make organic materials emit light under the action of an electric field. They have the characteristics of high contrast, ultra-thin flexible display, and short response time.

[0003] At present, OLED display technology has achieved rapid development. While meeting the personalized needs of users, it has also exposed some problems. Since it uses organic materials for self-luminescence, the lifespan of OLED is generally short, and too short a lifespan will seriously affect the user experience.

[0004] The inventors have discovered that there are at least the following problems in the prior art: In the prior art, the current density can be reduced by increasing the aperture ratio, thereby increasing the life of the OLED, wherein the aperture ratio is the ratio of the pixel area to the screen display area. However, due to the limitations of process conditions, deliberately increasing the aperture ratio will lead to a decrease in product yield. Summary of the invention

[0005] The present invention aims to solve the problems that the existing OLED with low aperture ratio has short life span and the OLED with high aperture ratio has low yield rate, and provides an organic light emitting diode device, a display panel and a display device.

[0006] The technical solution adopted to solve the technical problem of the present invention is:

[0007] An organic light emitting diode device comprises a substrate, a light emitting unit and a first structural layer arranged on the substrate and on one side of the substrate, wherein the light emitting unit is arranged on a side of the first structural layer away from the substrate, and the surface area of ​​the light emitting surface of the light emitting unit is larger than the orthographic projection area of ​​the light emitting unit on the substrate.

[0008] Optionally, the light emitting surface of the light emitting unit includes a curved surface convex toward a side close to the substrate.

[0009] Optionally, the curved surface includes a spherical cap-shaped curved surface or a concave-convex curved surface composed of a plurality of spherical cap-shaped surfaces.

[0010] Optionally, the radius of the bottom circle of the spherical cap is r, the height of the spherical cap is H, wherein the range of arctan (H / r) is 20° to 40°.

[0011] Optionally, a surface of the first structural layer close to the light-emitting unit and a surface of the light-emitting unit close to the first structural layer have shapes corresponding to each other and are in contact with each other.

[0012] Optionally, in a direction perpendicular to the surface where the substrate is located, a size of the first structural layer is between 1 and 4 microns.

[0013] Optionally, a plurality of pixel defining structures are further provided on a side of the first structural layer away from the substrate, and the light-emitting units are provided between adjacent pixel defining structures, and the adjacent pixel defining structures define a positive projection area of ​​the light-emitting units on the substrate.

[0014] Optionally, the organic light emitting diode device is of top emission type, a packaging layer is further provided on a side of the pixel defining structure away from the substrate, and a spacer is provided between the pixel defining structure and the packaging layer.

[0015] Optionally, the light-emitting unit includes a cathode and an anode, and an organic light-emitting material layer disposed between the cathode and the anode.

[0016] Optionally, the light-emitting unit further includes a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer.

[0017] Optionally, a thin film transistor (TFT) is provided between the light emitting unit and the substrate, the TFT comprises an active layer, a gate, a source electrode and a drain electrode, and the drain electrode is connected to the anode electrode.

[0018] Optionally, a light adjustment component is provided outside the light emitting surface of the light emitting unit, which is used to convert the light of the light adjustment component emitted by the light emitting unit into parallel light for emission.

[0019] Optionally, the light adjustment component includes a lens.

[0020] The present invention also provides a method for preparing an organic light emitting diode device, comprising the following steps:

[0021] forming a first structural layer on one side of the substrate;

[0022] forming a light-emitting unit on a side of the first structural layer away from the substrate;

[0023] Wherein, the surface area of ​​the light emitting surface of the light emitting unit is larger than the orthographic projection area of ​​the light emitting unit on the substrate;

[0024] The forming of the first structural layer comprises:

[0025] forming a planarization layer;

[0026] A curved surface convex toward a side close to the substrate is formed on a surface of the planarization layer away from the substrate to obtain a first structure layer.

[0027] The present invention also provides a display panel, comprising the above-mentioned organic light emitting diode device.

[0028] The present invention also provides a display device, comprising the above-mentioned display panel.

[0029] The light-emitting unit in the organic light-emitting diode device of the present invention is a non-planar structure, and the surface area of ​​its light-emitting surface is larger than its orthographic projection area on the substrate, which is equivalent to increasing the light-emitting area while keeping the pixel aperture ratio of the OLED display area unchanged, that is, ensuring the yield of the OLED product, and at the same time reducing the current density of the light-emitting unit, thereby significantly improving the life of the OLED. The organic light-emitting diode device of the present invention is suitable for various display devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1-4 is a schematic structural diagram of an organic light emitting diode device according to Example 1 of the present invention;

[0031] Figure 5-6 is a comparison diagram of the ratio of the brightness of the organic light emitting diode device to the initial brightness changing over time according to Example 1 of the present invention;

[0032] Among them, the figure markings are: 10, substrate; 2, light-emitting unit; 21, cathode; 22, anode; 23, organic light-emitting material layer; 3, first structure layer; 4, pixel defining structure; 5, encapsulation layer; 6, spacer; 71, active layer; 72, gate; 73, source; 74, drain. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0034] Embodiment 1:

[0035] This embodiment provides an organic light emitting diode device, such as Figure 1 As shown, it includes a substrate 10 and a first structure layer 3 and a light-emitting unit 2 arranged on the same side of the substrate 10, wherein the light-emitting unit 2 is arranged on the side of the first structure layer 3 away from the substrate 10, wherein the surface area of ​​the light-emitting surface of the light-emitting unit 2 is larger than the orthographic projection area of ​​the light-emitting unit 2 on the substrate 10.

[0036] The light-emitting unit 2 in the organic light-emitting diode device of this embodiment is a non-planar structure, and the surface area of ​​its light-emitting surface is larger than its orthographic projection area on the substrate 10. Compared with the prior art, the pixel aperture ratio (pixel aperture ratio refers to the ratio between the orthographic projection area of ​​the light-emitting unit 2 on the substrate 10 and the area of ​​a sub-pixel as a whole) equivalent to the OLED display area can remain unchanged, thereby ensuring the yield rate of OLED products; at the same time, increasing the area of ​​its light-emitting region can reduce the current density of the light-emitting unit 2, thereby improving the life of the OLED, and the improvement effect is significant.

[0037] As a preferred solution of this embodiment, the surface of the first structure layer 3 close to the light emitting unit 2 corresponds to the shape of the surface of the light emitting unit 2 close to the first structure layer 3 and contacts with each other.

[0038] The corresponding attachment of this embodiment Figure 1 It is shown in the figure that a first structural layer 3 is provided above the substrate 10. The first structural layer 3 is similar to the existing flat layer, except that the position of the first structural layer 3 corresponding to the light-emitting unit 2 on the surface of the side away from the substrate 10 is a non-planar structure. The light-emitting unit 2 is provided on the first structural layer 3, and the surfaces close to each other are in contact and fit with each other. Among them, the first structural layer 3 has the following functions: first, supporting the non-planar light-emitting unit 2. Specifically, the first structural layer 3 can be used as a support to form various functional layers of the light-emitting unit 2 thereon, which is conducive to process preparation and has a high product yield. Second, the first structural layer 3 is used as a support for the light-emitting unit 2. The concave structure of the first structural layer 3 can define the shape of the light-emitting unit 2. That is, the boundary of the concave structure of the first structural layer 3 can define the boundary of the light-emitting pixel. Specifically, the thickness of the first structural layer 3 is 1-4μm. When its thickness is greater than 4μm, it will cause the product thickness to increase. If its thickness is less than 1μm, it is not conducive to forming a non-planar structure at the position corresponding to the light-emitting unit 2.

[0039] As an optional solution of this embodiment, the light emitting surface of the light emitting unit 2 includes a curved surface convex toward the side close to the substrate 10. Figure 1 It is shown in the figure that the surface of the first structure layer 3 away from the substrate 10 at the position corresponding to the light-emitting unit 2 is a concave structure, that is, convex downward, and the light-emitting unit 2 is formed based on the concave structure. As an optional solution of this embodiment, the curved surface includes a spherical crown curved surface or a concave-convex curved surface composed of multiple spherical crowns. Figure 2 It is shown in FIG. 1 that the light emitting surface of the light emitting unit 2 is wavy.

[0040] It can be seen that the surface area S' of the light-emitting unit 2 is larger than its orthographic projection area S0, that is, the orthographic projection area S0 of the light-emitting unit 2 may not be changed compared with the prior art. At the same time, since the life span t of the OLED is proportional to 1 / (j*n) (n is an acceleration factor, generally between 1.2 and 1.9), the smaller the current density j, the longer the life span t of the OLED. In this embodiment, the current density j is reduced by increasing the pixel light-emitting surface area S', so the life span t of the OLED is longer.

[0041] As a specific solution of this embodiment, Figure 3As shown, a plurality of pixel defining structures 4 are further provided on the side of the first structural layer 3 away from the substrate 10 , and the light-emitting units 2 are provided between adjacent pixel defining structures 4 , and the adjacent pixel defining structures 4 define the positive projection area of ​​the light-emitting units 2 on the substrate 10 .

[0042] It should be noted that due to process limitations, the boundary definition of the light-emitting unit 2 defined by the concave structure of the first structural layer 3 is poor, so the role of adding the pixel defining structure 4 here is to clearly define the boundary of the light-emitting pixel. More specifically, the pixel defining structure 4 is arranged below the cathode 21, and at least part of the edge position of the organic light-emitting material layer is covered by the pixel defining structure 4, thereby clearly defining the boundary of the light-emitting pixel.

[0043] As a specific solution of this embodiment, the light-emitting unit 2 includes a cathode 21 , an anode 22 and an organic light-emitting material layer 23 . Preferably, an electron transport layer and a hole transport layer are further provided between the cathode 21 and the anode 22 .

[0044] As a preferred solution of this embodiment, the organic light emitting diode device is a top emission type, and a packaging layer 5 is further provided on the side of the pixel defining structure 4 away from the substrate, and a spacer 6 is provided between the pixel defining structure 4 and the packaging layer 5 .

[0045] In this embodiment, the specific light-emitting structure of the light-emitting unit 2 is not particularly limited. Generally, the light-emitting unit 2 includes a cathode 21, an anode 22, and an organic light-emitting material layer 23 disposed between the cathode 21 and the anode 22. Further, the light-emitting unit 2 can be a light-emitting structure with more layers, for example, it can include a hole injection layer (HIL), a hole transport layer (HTL), an emitting material layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL).

[0046] In one embodiment, a backplane circuit is further provided on the substrate 10, and the backplane circuit generally includes a driving transistor and a switching transistor, wherein the drain electrode 74 of the driving transistor is connected to the anode electrode 22 of the light-emitting unit 2, and is used to drive and control the light-emitting unit 2 to emit light. That is, a TFT is provided between the light-emitting unit 2 and the substrate 10, and the TFT includes an active layer 71, a gate electrode 72, a source electrode 73 and a drain electrode 74, and the drain electrode 74 is connected to the anode electrode 22.

[0047] The attached Figure 3It is shown in the figure: a plurality of spacers 6 are provided on the pixel defining structure 4, and a packaging layer 5 covering the light-emitting unit 2 is provided on the plurality of spacers 6, wherein the packaging layer 5 can be made of glass, and the packaging layer 5 surrounds the light-emitting unit 2 into a sealed space, and its function is to protect the organic light-emitting material of the internal light-emitting unit 2, prevent external water and oxygen from entering the internal structure, and further improve the product life.

[0048] In one embodiment, a light adjusting component is disposed outside the light emitting surface of the light emitting unit 2, which is used to convert the light of the light adjusting component incident from the light emitting unit 2 into parallel light for emission.

[0049] That is to say, in this embodiment, a light adjustment component is embedded on the encapsulation layer 5. Specifically, the light adjustment component can be a lens formed by a nano-imprinting process. The function of the lens is to make the light output of the non-planar light emitting unit 2 more uniform.

[0050] It should be noted that the present embodiment provides a top-emitting OLED. It is understandable that a bottom-emitting OLED with a similar structure can also be prepared by referring to the above-mentioned top-emitting OLED. This bottom-emitting OLED can also keep the pixel aperture ratio unchanged, greatly improving the life of its product. In addition, the concave structure of the first structural layer 3 in the present embodiment is convex downward. It is understandable that it can also be set as a similar structure that is convex upward. In this way, the light-emitting surface area of ​​the light-emitting unit 2 formed by the first structural layer 3 that is convex upward is also relatively large, thereby achieving the purpose of improving the life of its product.

[0051] As a preferred solution of the present invention, the light emitting surface of the light emitting unit 2 is a spherical crown surface, the radius of the bottom circle of the spherical crown is r, the height of the spherical crown is H, wherein the range of arctan (H / r) is 20° to 40°.

[0052] It should be noted that if Figure 4 As shown, usually the part of the sphere intercepted by the plane is the spherical cap. The center point of the sphere is shown in the figure as O. The spherical cap is a curved surface, which is a part of the sphere. The intercepted circle is the bottom circle of the spherical cap. The center of the bottom circle is O', the radius of the bottom circle is r, and the section perpendicular to the diameter of the cross section is the height H of the spherical cap. The radius of the bottom circle r forms a right triangle with the height H of the spherical cap, and the angle relative to the height H of the spherical cap is θ. That is, θ=arctan(H / r). In this embodiment, when θ is less than 20°, the luminous life of the product is improved. When θ is greater than 20°, the luminous life of the product is significantly improved. However, when θ is greater than 40°, the cathode 21 on the upper layer of the light-emitting unit 2 is prone to disconnection.

[0053] In this embodiment, specific experimental data of three groups of spherical crown-shaped light-emitting units 2 are given, and the acceleration factor n in this embodiment is selected as 1.6. The θ of the first group of spherical crowns is 20°, the radius of the bottom circle of the spherical crown is r1, and the surface area of ​​the spherical crown is S1; the θ of the second group of spherical crowns is 30°, the radius of the bottom circle of the spherical crown is r2, and the surface area of ​​the spherical crown is S2; the θ of the third group of spherical crowns is 40°, the radius of the bottom circle of the spherical crown is r3, and the surface area of ​​the spherical crown is S3; wherein, r1=r2=r3, S1<S2<S3. The light-emitting surface area S0 of the light-emitting unit 2 of the comparison group is the same as its orthographic projection area S' on the substrate 10. The pixel aperture ratio AR refers to the ratio between the orthographic projection area S0 of the light-emitting unit 2 on the substrate 10 and the area of ​​a sub-pixel as a whole. The light-emitting aperture ratio AR' refers to the ratio between the light-emitting surface area S' and the area of ​​a sub-pixel as a whole. See Table 1 for specific data of each group.

[0054] Table 1

[0055]

[0056] The luminance meter CA2000 (other similar luminance meters, such as PR788, etc., can also be used for testing, and the test results of other instruments are the same as those of this embodiment) is used to test the luminance life LT95 (usually the time when the brightness of the luminance unit 2 decreases to 95% of the initial brightness L0 is used to evaluate the device life, also known as LT95) of the three groups of spherical crown luminance units 2 and the comparison group of luminance units 2. The test results are shown in Table 2. RGB represents red, green, and blue sub-pixels respectively.

[0057] Table 2

[0058]

[0059] It can be seen that when θ of the first set of spherical crowns is 20°, LT95 is increased to 163.2%; when θ of the second set of spherical crowns is 30°, LT95 is increased to 206.4%; when θ of the third set of spherical crowns is 40°, LT95 is increased to 264.0%, and the improvement effect is significant.

[0060] Attached Figure 5 , Attachment Figure 6 It is a comparison diagram of the ratio of the brightness (Lt) to the initial brightness (L0) of the three groups of spherical crown light-emitting units 2 and the light-emitting unit 2 of the comparison group changing with time. Figure 5 This is a graph showing the luminescence up to 1400 hours. Figure 6 It is a curve chart of luminescence to 10000 hours. It can be seen from the figure that with the extension of luminescence time, the Lt / L0 of the third group is better than that of the second group, the Lt / L0 of the second group is better than that of the first group, and the Lt / L0 of the first group is better than that of the control group.

[0061] The size, thickness, etc. of each structural layer shown in the drawings of this embodiment are for illustration only. In the process implementation, the projected areas of each structural layer on the substrate may be the same or different, and the like are not listed here. The required projected areas of each structural layer may be achieved through etching process; at the same time, the structure shown in the drawings does not limit the geometric shapes of each structural layer, which may also be achieved through etching.

[0062] Embodiment 2:

[0063] This embodiment provides a method for preparing an organic light emitting diode device, comprising the following steps:

[0064] S01. Forming a planarization layer on a substrate.

[0065] S02, forming a concave structure protruding toward a side close to the substrate on a surface of the planarization layer away from the substrate to obtain a first structural layer with a curved surface; specifically, the concave structure in this step can be realized by etching and other processes.

[0066] S03. Forming a light-emitting unit on a side of the concave structure of the first structural layer away from the substrate, wherein a surface area of ​​a light-emitting surface of the light-emitting unit is larger than an orthographic projection area of ​​the light-emitting unit on the substrate.

[0067] Embodiment 3:

[0068] This embodiment provides a display panel, comprising the organic light emitting diode device of the above embodiment.

[0069] The display panel of this embodiment adopts the organic light emitting diode device of the above embodiment, and the display panel has a high product yield and a long product life.

[0070] Embodiment 4:

[0071] This embodiment provides a display device, including the above-mentioned display panel. The display device can be: electronic paper, OLED panel, mobile phone, tablet computer, television, monitor, notebook computer, digital photo frame, navigator, or any other product or component with display function.

[0072] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An organic light emitting diode device, characterized in that: It comprises a substrate, and a light-emitting unit and a first structure layer arranged on one side of the substrate, wherein a surface of the first structure layer close to the light-emitting unit corresponds to a surface of the light-emitting unit close to the first structure layer in shape and contacts with each other; wherein the light-emitting unit is arranged on a side of the first structure layer away from the substrate, and a surface area of ​​a light-emitting surface of the light-emitting unit is larger than an orthographic projection area of ​​the light-emitting unit on the substrate; The light-emitting surface of the light-emitting unit includes a curved surface convex toward the side close to the substrate, and the curved surface includes a spherical crown curved surface or a concave-convex curved surface composed of multiple spherical crowns; the radius of the bottom circle of the spherical crown is r, and the height of the spherical crown is H, wherein arctan (H / r) is less than or equal to 40°.

2. The organic light emitting diode device according to claim 1, characterized in that: The range of arctan(H / r) is 20° to 40°.

3. The organic light emitting diode device according to claim 1, characterized in that: A plurality of pixel defining structures are further provided on the side of the first structural layer away from the substrate. The light-emitting units are provided between adjacent pixel defining structures. The adjacent pixel defining structures define the orthographic projection area of ​​the light-emitting units on the substrate.

4. The organic light emitting diode device according to claim 3, characterized in that: The organic light emitting diode device is of top emission type, a packaging layer is further provided on the side of the pixel defining structure away from the substrate, and a spacer is provided between the pixel defining structure and the packaging layer.

5. The organic light emitting diode device according to claim 1, characterized in that: The light emitting unit includes a cathode and an anode, and an organic light emitting material layer disposed between the cathode and the anode.

6. The organic light emitting diode device according to claim 5, characterized in that: The light-emitting unit further includes a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer.

7. The organic light emitting diode device according to claim 5, characterized in that: A thin film transistor is arranged between the light emitting unit and the substrate. The thin film transistor comprises an active layer, a gate electrode, a source electrode and a drain electrode. The drain electrode is connected to the anode electrode.

8. The organic light emitting diode device according to claim 1, characterized in that: A light adjustment component is disposed outside the light emitting surface of the light emitting unit, and is used for converting the light of the light adjustment component incident from the light emitting unit into parallel light for emission.

9. The organic light emitting diode device according to claim 8, characterized in that: The light adjustment component includes a lens.

10. A method for preparing an organic light emitting diode device, characterized in that: The following steps are involved: forming a first structural layer on one side of the substrate; forming a light-emitting unit on a side of the first structural layer away from the substrate; Wherein, the surface area of ​​the light emitting surface of the light emitting unit is larger than the orthographic projection area of ​​the light emitting unit on the substrate; The forming of the first structural layer comprises: forming a planarization layer; A curved surface convex toward a side close to the substrate is formed on a surface of the planarization layer away from the substrate to obtain a first structure layer.

11. A display panel, characterized in that: An organic light emitting diode device comprising any one of claims 1 to 9.

12. A display device, characterized in that: Includes the display panel as claimed in claim 11.

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