Display panel and display device thereof

Abstract

The present invention relates to a display panel and a display device thereof. The display panel includes: a substrate; an organic light-emitting device located on the substrate; a cover layer located on the organic light-emitting device; a light extraction layer located on the cover layer; an optical functional layer located on the light extraction layer; and a packaging layer located on the optical functional layer. The refractive index of the light extraction layer is less than the refractive index of the cover layer and less than the refractive index of the portion of the packaging layer closest to the optical functional layer. The refractive index of the optical functional layer is less than the refractive index of the portion of the packaging layer closest to the optical functional layer and not equal to the refractive index of the light extraction layer.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of display technologies, and more particularly, to a display panel and a display device thereof. Background Art

[0002] Organic Light-Emitting Diode (OLED) display panels have the advantages of self-luminescence, high efficiency, vivid colors, thinness, light weight, power saving, rollability, and a wide operating temperature range, and have been gradually applied in the fields of large-area display, lighting, and in-vehicle display. Summary of the Invention

[0003] Embodiments of the present invention provide a display panel and a display device thereof, which can improve display problems caused by color shift and enhance the display effect of the display panel.

[0004] One aspect of the present invention provides a display panel. The display panel includes: a substrate; an organic light-emitting device located on the substrate; a cover layer located on the organic light-emitting device; a light extraction layer located on the cover layer; an optical functional layer located on the light extraction layer; and a packaging layer located on the optical functional layer. The refractive index of the light extraction layer is less than the refractive index of the cover layer and less than the refractive index of the portion of the packaging layer closest to the optical functional layer. The refractive index of the optical functional layer is less than the refractive index of the portion of the packaging layer closest to the optical functional layer and not equal to the refractive index of the light extraction layer.

[0005] In an embodiment of the present invention, the refractive index of the optical functional layer is greater than the refractive index of the light extraction layer.

[0006] In an embodiment of the present invention, the range of the difference between the refractive index of the optical functional layer and the refractive index of the portion of the packaging layer closest to the optical functional layer is 0.03 - 0.3.

[0007] In an embodiment of the present invention, the ratio range of the thickness of the optical functional layer to the thickness of the portion of the packaging layer closest to the optical functional layer is 0.04 - 0.21.

[0008] In an embodiment of the present invention, the material of the optical functional layer is the same as the material of the portion of the packaging layer closest to the optical functional layer.

[0009] In an embodiment of the present invention, the material of the optical functional layer includes silicon oxynitride. Wherein, the oxygen content in the material of the optical functional layer is greater than the oxygen content in the material of the portion of the packaging layer closest to the optical functional layer.

[0010] In an embodiment of the present invention, the material of the optical functional layer includes silicon oxide.

[0011] In an embodiment of the present invention, the refractive index of the optical functional layer is less than that of the light extraction layer.

[0012] In an embodiment of the present invention, the encapsulation layer includes a first encapsulation layer, a second encapsulation layer, and a third encapsulation layer sequentially arranged in a direction away from the substrate. The first encapsulation layer includes the portion of the encapsulation layer closest to the optical functional layer.

[0013] In an embodiment of the present invention, the refractive index of the second encapsulation layer is less than that of the first encapsulation layer and less than that of the third encapsulation layer.

[0014] In an embodiment of the present invention, the refractive index of the first encapsulation layer is 1.73, the refractive index of the second encapsulation layer is 1.54, and the refractive index of the third encapsulation layer is 1.84.

[0015] In an embodiment of the present invention, the thickness of the first encapsulation layer is 950 nm, the thickness of the second encapsulation layer is 12 μm, and the thickness of the third encapsulation layer is 700 nm.

[0016] In an embodiment of the present invention, the material of the light extraction layer includes an organic polymer material or lithium fluoride.

[0017] In an embodiment of the present invention, the organic light-emitting device includes an anode, an organic light-emitting layer, and a cathode sequentially arranged in a direction away from the substrate.

[0018] One aspect of the present invention provides a display device. The display device includes the display panel as described above.

[0019] Further aspects and scopes of adaptability become apparent from the description provided herein. It should be understood that the various aspects of the present application can be implemented alone or in combination with one or more other aspects. It should also be understood that the description herein and the specific embodiments are for illustrative purposes only and are not intended to limit the scope of the present application. Description of the Drawings

[0020] The drawings described herein are for illustrative purposes only of the selected embodiments and are not all possible implementations and are not intended to limit the scope of the present application, wherein:

[0021] Figure 1 A cross-sectional structural schematic diagram of an OLED display panel 10 is shown.

[0022] Figure 2 A cross-sectional structural schematic diagram of a display panel according to an embodiment of the present invention is shown.

[0023] Figure 3 The schematic plan view of a display device according to an embodiment of the present disclosure is shown.

[0024] Throughout the various views of these drawings, corresponding reference numerals indicate corresponding components or features. Detailed implementation manners

[0025] First of all, it should be noted that unless otherwise explicitly indicated in the context, the singular forms of words used in this specification and the appended claims include the plural, and vice versa. Thus, when referring to the singular, it generally includes the plural of the corresponding term. Similarly, the terms "comprising" and "including" will be interpreted as inclusive rather than exclusive. Likewise, the terms "including" and "or" should be interpreted as inclusive, unless otherwise stated in this specification. Where the term "example" is used in this specification, especially when it is located after a group of terms, the said "example" is merely exemplary and illustrative, and should not be considered exclusive or extensive.

[0026] In addition, it should also be noted that when introducing the elements and embodiments of the present application, the articles "a", "an", "the" and "said" are intended to indicate the existence of one or more elements; unless otherwise stated, the meaning of "a plurality" is two or more; the terms "comprising", "including", "containing" and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements; the terms "first", "second", "third", etc. are only for descriptive purposes and cannot be construed as indicating or implying relative importance and formation order.

[0027] Secondly, in the drawings, the thicknesses of the layers and regions are exaggerated for clarity. It should be understood that when a layer, region, or component is referred to as being "on" another part, it means that it is directly on the other part, or there may be other components in between. On the contrary, when a component is referred to as being "directly" on another component, it means that there are no other components in between.

[0028] The flowcharts depicted in the present invention are merely examples. Without departing from the spirit of the present invention, there can be many variations of the flowchart or the steps described therein. For example, the said steps can be performed in a different order, or steps can be added, deleted, or modified. These variations are all considered to be part of the aspects claimed.

[0029] Exemplary embodiments will now be described more fully with reference to the accompanying drawings.

[0030] At present, with the increasingly widespread application of OLED display technology, the requirements for OLED display panels are getting higher and higher. Among them, color shift is an important indicator determining the display effect. Technicians in the display field have been committed to researching technical means to suppress color shift.

[0031] Research shows that the color shift of OLED display panels is related to the microcavity effect caused by the electrode layer in OLED devices. Figure 1 The cross-sectional structure schematic diagram of an OLED display panel 10 is shown. As Figure 1 shown, the display panel 10 may include: a substrate 100, an OLED device 200 located on the substrate 100, a cover layer 300 located on the OLED device 200, a light extraction layer 400 located on the cover layer 300, and a packaging layer 600 located on the light extraction layer 400. The OLED device 200 may include an anode 201, a light-emitting layer 202, and a cathode 203 sequentially arranged in a direction perpendicular to the substrate 100. The cover layer 300 may be configured to block oxygen and moisture from entering the display panel 10 from the outside. Additionally, the cover layer 300 may also be configured to improve the extraction efficiency of the light emitted by the light-emitting layer 202. The light extraction layer 400 may be configured to improve the extraction efficiency of the light emitted from the OLED device 200. Additionally, the light extraction layer 400 may be configured to protect the cover layer 300 and the OLED device 200 from being damaged.

[0032] For this display panel, the anode 201, the light-emitting layer 202, and the cathode 203 form a microcavity 101. The microcavity 101 can cause the light emitted from the light-emitting layer 102 to be repeatedly reflected and re-reflected between the anode 201 and the cathode 203, resulting in constructive interference and being amplified, thereby increasing the intensity and purity of the light. However, the directivity of the light will also be correspondingly enhanced. This results in different light intensities in different directions. Therefore, at different angles (especially at large viewing angles), the display panel has an obvious color shift phenomenon. However, the material and parameter selection of the electrode layer and the organic light-emitting layer of the OLED device involve various key design considerations. Therefore, it is difficult to eliminate color shift by adjusting the OLED device structure.

[0033] For this technical challenge, the inventors found through in-depth research that in addition to the microcavity 101 formed by the electrode layers of the OLED device causing color shift, the stack of transparent materials on the cathode 203 of the OLED device also has an important impact on color shift. For example, if the cover layer 300, the light extraction layer 400, and the encapsulation layer 600 form a refractive index configuration with alternating high and low levels, they will constitute a distributed Bragg reflector (DBR, Distributed Bragg Reflector) 102. Here, it should be understood that the distributed Bragg reflector can be composed of alternately arranged high refractive index layers and low refractive index layers. When light passes through these film layers with different refractive indices, since the light reflected back from each layer interferes due to the change in the phase angle and then combines with each other, strong reflected light is obtained. The Bragg reflector 102 and the cathode 203 can also form an additional microcavity 103. Similar to the above microcavity 101, light is reflected multiple times within the microcavity 103, and finally, under the action of interference superposition, the intensity of the emitted light increases, and the directivity of this light is enhanced, thereby further enhancing the color shift. In addition, the existence of the microcavities 101 and 103 will also reduce the light extraction efficiency of the display panel.

[0034] To address the above problems, embodiments of the present invention provide a display panel that can reduce the microcavity effect, thereby improving color shift and increasing light extraction efficiency.

[0035] Figure 2 A schematic cross-sectional structure diagram of a display panel according to an embodiment of the present invention is shown. As Figure 2 shown, the display panel 20 may include: a substrate 100; an organic light-emitting device 200 located on the substrate 100; a cover layer 300 located on the organic light-emitting device 200; a light extraction layer 400 located on the cover layer 300; an optical functional layer 500 located on the light extraction layer 400; and an encapsulation layer 600 located on the optical functional layer 500. In an embodiment of the present invention, the refractive index of the light extraction layer 400 may be less than the refractive index of the cover layer 300 and less than the refractive index of the portion 601 of the encapsulation layer 600 closest to the optical functional layer 500.

[0036] In an embodiment of the present invention, the refractive index of the optical functional layer 500 may be less than the refractive index of the portion 601 of the encapsulation layer 600 closest to the optical functional layer 500 and not equal to the refractive index of the light extraction layer 400. By inserting the optical functional layer 500 between the light extraction layer 400 and the encapsulation layer 600, the previously formed refractive index configuration with alternating high and low levels by the cover layer 300, the light extraction layer 400, and the encapsulation layer 600 is disrupted. That is, by setting the optical functional layer 500, a distributed Bragg reflector cannot be formed by the multiple film layers on the cathode 203, and thus, a microcavity cannot be formed between the cathode and the dielectric stack on the cathode, thereby reducing the contribution of the dielectric stack to color shift.

[0037] According to an embodiment of the present invention, after the optical functional layer 500 is provided, the number of times that light is reflected back and forth between the cathode 203 and the dielectric stack above the cathode 203 is reduced, and the effect of interference superposition becomes smaller, thereby eliminating or weakening the microcavity effect. Thereby, the color shift and light extraction efficiency of the display panel 20 are improved, and the display effect is enhanced.

[0038] According to an embodiment of the present invention, in order to make the cover layer 300, the light extraction layer 400, and the encapsulation layer 600 no longer satisfy the refractive index configuration of high and low alternation, the refractive index of the optical functional layer 500 can be set to be less than the refractive index of the portion 601 closest to the optical functional layer 500 in the encapsulation layer 600 and not equal to the refractive index of the light extraction layer 400.

[0039] As an example, the refractive index of the optical functional layer 500 can be greater than the refractive index of the light extraction layer 400. As another example, the refractive index of the optical functional layer 500 can be less than the refractive index of the light extraction layer 400.

[0040] An embodiment in which the refractive index of the optical functional layer 500 is greater than the refractive index of the light extraction layer 400 is described below.

[0041] In an exemplary embodiment of the present invention, the range of the difference between the refractive index of the optical functional layer 500 and the refractive index of the portion 601 closest to the optical functional layer 500 in the encapsulation layer 600 can be 0.03 - 0.33.

[0042] In an exemplary embodiment of the present invention, the range of the ratio of the thickness of the optical functional layer 500 to the thickness of the portion 601 closest to the optical functional layer 500 in the encapsulation layer 600 can be 0.04 - 0.21.

[0043] In an exemplary embodiment of the present invention, the refractive index range of the optical functional layer 500 can be 1.4 - 1.7. As an example, the refractive index of the optical functional layer 500 can be 1.52.

[0044] In an exemplary embodiment of the present invention, the thickness range of the optical functional layer 500 can be 40 - 200 nm. As an example, the thickness of the optical functional layer 500 is 50 nm.

[0045] In an exemplary embodiment of the present invention, the material of the optical functional layer 500 can include silicon oxynitride or silicon oxide.

[0046] In an exemplary embodiment of the present invention, the material of the optical functional layer 500 may be the same as the material of the portion 601 of the encapsulation layer 600 closest to the optical functional layer 500. For example, the material of the optical functional layer 500 may include silicon oxynitride. In this case, the oxygen content in the material of the optical functional layer 500 is greater than the oxygen content in the material of the portion 601 of the encapsulation layer 600 closest to the optical functional layer 500.

[0047] It can be understood that, for example, when the materials of different film layers all include silicon oxynitride, the refractive indices of different film layers can be adjusted by adjusting the different proportions of the components included in the materials. Generally, when the oxygen content in the material is increased, the refractive index of the corresponding film layer will become lower.

[0048] Next, an embodiment in which the refractive index of the optical functional layer 500 is less than the refractive index of the light extraction layer 400 will be described.

[0049] In an exemplary embodiment of the present invention, the refractive index of the cover layer 300 is greater than the refractive index of the cathode 203.

[0050] In an exemplary embodiment of the present invention, as described above, the cover layer 300 may be configured to block oxygen and moisture from entering the display panel 10 from the outside. Thus, the cover layer 300 may include a material that satisfies the above functions. For example, the material of the cover layer 300 may include silicon nitride.

[0051] In an exemplary embodiment of the present invention, the refractive index of the light extraction layer 400 may be 1.35.

[0052] In an exemplary embodiment of the present invention, the material of the light extraction layer 400 may include an organic polymer material. As an example, the organic polymer material may include triarylamines, cyclic ureas, acyl structures, dibenzothiophenes, dibenzofurans, carbazoles, etc.

[0053] In an exemplary embodiment of the present invention, the material of the light extraction layer 400 may further include lithium fluoride.

[0054] In an exemplary embodiment of the present disclosure, the encapsulation layer 600 may include a first encapsulation layer 601, a second encapsulation layer 602, and a third encapsulation layer 603 that are sequentially arranged in a direction away from the substrate. It should be noted that the first encapsulation layer 601 here corresponds to the portion 601 of the above encapsulation layer 600 closest to the optical functional layer 500.

[0055] In an exemplary embodiment of the present disclosure, the refractive index of the second encapsulation layer 602 may be less than the refractive index of the first encapsulation layer 601 and less than the refractive index of the third encapsulation layer 603.

[0056] In an exemplary embodiment of the present invention, the refractive index of the first encapsulation layer 601 may be 1.73, the refractive index of the second encapsulation layer 502 may be 1.54, and the refractive index of the third encapsulation layer 603 may be 1.84.

[0057] In an exemplary embodiment of the present invention, the thickness of the first encapsulation layer 601 may be 950 nm, the thickness of the second encapsulation layer 602 may be 12 μm, and the thickness of the third encapsulation layer 603 may be 700 nm.

[0058] In an exemplary embodiment of the present invention, the material of the first encapsulation layer 601 may include silicon oxynitride, the material of the second encapsulation layer 602 may include organic ink, and the material of the third encapsulation layer 603 may include silicon nitride.

[0059] In an exemplary embodiment of the present invention, the organic light-emitting device 200 may include an anode 201, an organic light-emitting layer 202, and a cathode 203 that are sequentially disposed in a direction away from the substrate 100.

[0060] In an exemplary embodiment of the present invention, a hole injection layer and a hole transport layer may be disposed between the organic light-emitting layer 202 and the anode 201, and an electron transport layer and an electron injection layer may be disposed between the organic light-emitting layer 202 and the cathode 203. However, the content of the present invention is not limited thereto. In addition, the organic light-emitting layer 202 may be a single-layer structure having a single light-emitting layer that emits red light, blue light, green light, or light of a similar color. Alternatively, the organic light-emitting layer 202 may have a multilayer structure in which two or more light-emitting layers are provided.

[0061] In an embodiment of the present invention, a display device is further provided that can reduce color shift.

[0062] Figure 3 A schematic plan view of a display device according to an embodiment of the present disclosure is shown. As Figure 3 shown, the display device 1 may include a display panel 20. For the description of the display panel 20, reference may be made to the above description, and details are not repeated herein.

[0063] In an exemplary embodiment of the present disclosure, the display device 1 may be, for example, an OLED display device. As other examples, the display device 1 may be, for example, a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a navigator, a wearable device, an e-book reader, etc.

[0064] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the present application. The various elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where appropriate, these elements and features are interchangeable and can be used in the selected embodiment, even if not specifically shown or described. Similarly, they can be varied in many ways. Such variations are not to be regarded as a departure from the present application, and all such modifications are intended to be included within the scope of the present application.

Claims

1. A display panel, comprising: a substrate; an organic light-emitting device located on the substrate; a cover layer located on the organic light-emitting device; a light extraction layer located on the cover layer; an optical functional layer located on the light extraction layer; and a packaging layer located on the optical functional layer, wherein the refractive index of the light extraction layer is less than the refractive index of the cover layer and less than the refractive index of the portion of the packaging layer closest to the optical functional layer, the refractive index of the optical functional layer is less than the refractive index of the portion of the packaging layer closest to the optical functional layer and not equal to the refractive index of the light extraction layer.

2. The display panel according to claim 1, wherein, The refractive index of the optical functional layer is greater than the refractive index of the light extraction layer.

3. The display panel according to claim 2, wherein, The range of the difference in refractive index between the optical functional layer and the portion of the packaging layer closest to the optical functional layer is 0.03 - 0.

33.

4. The display panel according to claim 3, wherein, The ratio range of the thickness of the optical functional layer to the thickness of the portion of the packaging layer closest to the optical functional layer is 0.04 - 0.

21.

5. The display panel according to claim 1, wherein, The material of the optical functional layer is the same as the material of the portion of the packaging layer closest to the optical functional layer.

6. The display panel according to claim 5, wherein, The material of the optical functional layer includes silicon oxynitride, wherein the oxygen content in the material of the optical functional layer is greater than the oxygen content in the material of the portion of the packaging layer closest to the optical functional layer.

7. The display panel according to claim 4, wherein, The material of the optical functional layer includes silicon oxide.

8. The display panel according to claim 1, wherein, The refractive index of the optical functional layer is less than the refractive index of the light extraction layer.

9. The display panel according to claim 1 or 2, wherein The packaging layer includes a first packaging layer, a second packaging layer, and a third packaging layer sequentially arranged in a direction away from the substrate, wherein the first packaging layer includes the portion of the packaging layer closest to the optical functional layer.

10. The display panel according to claim 9, wherein, The refractive index of the second packaging layer is less than the refractive index of the first packaging layer and less than the refractive index of the third packaging layer.

11. The display panel according to claim 9, wherein, The refractive index of the first packaging layer is 1.73, the refractive index of the second packaging layer is 1.54, and the refractive index of the third packaging layer is 1.

84.

12. The display panel according to claim 9, wherein, The thickness of the first packaging layer is 950 nm, the thickness of the second packaging layer is 12 μm, and the thickness of the third packaging layer is 700 nm.

13. The display panel according to claim 1 or 2, wherein The material of the light extraction layer includes an organic polymer material or lithium fluoride.

14. The display panel according to claim 1 or 2, wherein, The organic light-emitting device includes an anode, an organic light-emitting layer, and a cathode sequentially arranged in a direction away from the substrate.

15. A display device, comprising the display panel according to any one of claims 1 - 14.

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