Display substrate, manufacturing method thereof, and display device
11700739 · 2023-07-11
Assignee
Inventors
Cpc classification
H10K50/852
ELECTRICITY
H10K71/00
ELECTRICITY
H10K59/38
ELECTRICITY
International classification
H10K50/818
ELECTRICITY
H10K50/852
ELECTRICITY
H10K59/38
ELECTRICITY
Abstract
A display substrate, a manufacturing method thereof, and a display device are provided. The display substrate includes: a base substrate; an anode structure, disposed on the base substrate; a light emitting layer, disposed on a side of the anode structure away from the base substrate; and a cathode layer, disposed on a side of the light emitting layer away from the base substrate, the anode structure includes a reflective layer and an inorganic layer disposed on a side of the reflective layer away from the base substrate, the cathode layer includes a transflective layer, and the inorganic layer is configured to adjust a distance between the reflective layer and the transflective layer.
Claims
1. A display substrate, comprising: a base substrate; an anode structure, disposed on the base substrate, comprising a first anode structure, a second anode structure and a third anode structure; an organic light emitting layer, disposed on a side of the anode structure away from the base substrate; a cathode layer, disposed on a side of the organic light emitting layer away from the base substrate, a color filter layer, disposed on a side of the cathode layer away from the base substrate, wherein the color filter layer comprises a first filter block of red color, a second filter block of green color and a third filter block of blue color, the first filter block, the second filter block and the third filter block are disposed respectively corresponding to the first anode structure, the second anode structure and the third anode structure; wherein the anode structure comprises a reflective layer, and a distance between the reflective layer in the second anode structure and the organic light emitting layer is greater than a distance between the reflective layer in the first anode structure and the organic light emitting layer, wherein an inorganic layer is between the reflective layer and the organic light emitting layer.
2. The display substrate according to claim 1, wherein the inorganic layer comprises a layer having a hole injection function.
3. The display substrate according to claim 1, wherein a total thickness of the inorganic layer between the reflective layer in the second anode structure and the organic light emitting layer is greater than a total thickness of the reflective layer.
4. The display substrate according to claim 1, wherein the organic light emitting layer is a continuous layer.
5. The display substrate according to claim 1, wherein the organic light emitting layer comprises a first sub organic light emitting layer and a second sub organic light emitting layer, and the first sub organic light emitting layer and the second sub organic light emitting layer are configured to emit light of different colors.
6. The display substrate according to claim 1, wherein the organic light emitting layer is configured to emit white light.
7. The display substrate according to claim 1, wherein at the second anode structure, the organic light emitting layer comprises a first slope part and a second slope part at edges of the second anode structure and comprises a flat part between the first slope part and the second slope part, and a slope angle of the first slope part and a slope angle of the second slope part are different at a same horizontal plane.
8. The display substrate according to claim 1, wherein an encapsulation layer is between the color filter layer and the organic light emitting layer, a distance H2 between a surface, close to the organic light emitting layer, of the encapsulation layer corresponding to the second anode structure and the reflective layer is greater than a distance H1 between a surface, close to the organic light emitting layer, of the encapsulation layer corresponding to the first anode structure and the reflective layer.
9. The display substrate according to claim 1, wherein a distance between the reflective layer in the second anode structure and the cathode layer is greater than a distance between the reflective layer in the first anode structure and the cathode layer.
10. The display substrate according to claim 1, wherein a material of the reflective layer comprises aluminum; and a material of the inorganic layer comprises titanium element.
11. The display substrate according to claim 1, wherein a material of the inorganic layer comprises molybdenum oxide or titanium nitride.
12. The display substrate according to claim 1, wherein a layer count of the inorganic layer is more than one, and a layer count of the cathode layer is more than one.
13. The display substrate according to claim 1, wherein the inorganic layer comprises a first sub inorganic layer, a second sub inorganic layer and a third sub inorganic layer.
14. A display substrate, comprising: a base substrate; an anode structure, disposed on the base substrate, comprising a first anode structure, a second anode structure and a third anode structure; an organic light emitting layer, disposed on a side of the anode structure away from the base substrate; a cathode layer, disposed on a side of the organic light emitting layer away from the base substrate, a color filter layer, disposed on a side of the cathode layer away from the base substrate, wherein the color filter layer comprises a first filter block, a second filter block and a third filter block, the first filter block, the second filter block and the third filter block are disposed respectively corresponding to the first anode structure, the second anode structure and the third anode structure; wherein at the second anode structure, the organic light emitting layer comprises a first slope part and a second slope part at edges of the second anode structure and comprises a flat part between the first slope part and the second slope part, and a slope angle of the first slope part and a slope angle of the second slope part are different at a same horizontal plane, wherein a distance between the first slope part and the base substrate gradually decreases in a direction away from the flat part.
15. The display substrate according to claim 14, wherein the first filter block is a red filter block, the second filter block is a green filter block, and the third filter block is a blue filter block.
16. The display substrate according to claim 14, wherein a distance between the second slope part and the base substrate gradually decreases in a direction away from the flat part.
17. The display substrate according to claim 14, wherein a distance between the flat part and the reflective layer is greater than or equal to a distance between the first slope part and the reflective layer; and the distance between the flat part and the reflective layer is greater than or equal to a distance between the second slope part and the reflective layer.
18. The display substrate according to claim 14, wherein an intersection of a tangent at a middle position of the first slope and a tangent at a middle position of the second slope is on a side of the reflective layer away from the base substrate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) In order to clearly illustrate the technical solution of embodiments of the present disclosure, the drawings of the embodiments will be briefly described in the following, it is obvious that the drawings in the description are only related to some embodiments of the present disclosure and not limited to the present disclosure.
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DETAILED DESCRIPTION
(7) In order to make objects, technical details and advantages of the embodiments of the disclosure apparent, the technical solutions of the embodiments will be described in a clearly and fully understandable way in connection with the drawings related to the embodiments of the disclosure. Apparently, the described embodiments are just a part but not all of the embodiments of the disclosure. Based on the described embodiments herein, those skilled in the art can obtain other embodiment(s), without any inventive work, which should be within the scope of the disclosure.
(8) Unless otherwise defined, all the technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms “first,” “second,” etc., which are used in the present disclosure, are not intended to indicate any sequence, amount or importance, but distinguish various components. Also, the terms “comprise,” “comprising,” “include,” “including,” etc., are intended to specify that the elements or the objects stated before these terms encompass the elements or the objects and equivalents thereof listed after these terms, but do not preclude the other elements or objects. “Connected” and “connecting” and the similar terms are not limited to physical or mechanical connection, and they also include electrical connection, direct connection or indirect connection.
(9) Organic Light Emitting Diode (OLED) display devices occupy an important position in micro display device filed due to their unique advantages. Due to the limitation of Fine Metal Mask (FMM), conventional OLED display device cannot achieve high PPI (Pixel Per Inch). Therefore, upon an OLED display device being used as a micro display device, the OLED display adopts a structure of white light+color film.
(10) Embodiments of the present disclosure provide a display substrate, a manufacturing method of the same, and a display device. The display substrate includes a base substrate, an anode structure provided on the base substrate, a light emitting layer provided on a side of the anode structure away from the base substrate, and a cathode layer provided on a side of the light emitting layer far from the base substrate. The anode structure includes a reflective layer and an inorganic layer disposed on a side of the reflective layer away from the substrate. The cathode layer includes a transflective layer, and the inorganic layer is configured to adjust the distance between the reflective layer and the transflective layer. Thus, the reflective layer and the transflective layer can constitute a micro cavity effect structure, and the distance between the reflective layer and the transflective layer can be adjusted by an additional inorganic layer, thereby narrowing the luminescence spectrum of the sub pixel corresponding to the anode structure, so as to further improve the color purity.
(11) Hereinafter, the display substrate, the manufacturing method thereof, and the display device provided by embodiments of the present disclosure will be described with reference to the accompanying drawings.
(12) An embodiment of the present disclosure provides a display substrate.
(13) In the display substrate provided in the present embodiment, the reflective layer in the anode structure and the transflective layer in the cathode layer can constitute a micro cavity effect structure, and the light emitting layer disposed between the anode structure and the cathode layer can be electroluminescent. The light directly emitted by the light emitting layer and the light reflected by the reflective layer can interfere with each other in the abovementioned micro cavity effect structure; light with a specific wavelength or a specific wavelength range can enhanced by adjusting the distance between the reflective layer and the transflective layer through the inorganic layer which is additionally provided, and light with other wavelengths is weakened, so that the luminescence spectrum of the sub pixel corresponding to the anode structure can be narrowed, thereby improving the color purity. Upon the display substrate provided in the present embodiment being applied to an OLED display device having a structure of white light plus a color filter, the color gamut of the OLED display can be improved under the premise of having a relatively high PPI by increasing the color purity of every sub pixels.
(14) For example, in the display substrate provided in an example of the present embodiment, the distance between the reflective layer and the transflective layer satisfies a following formula: D=j(λ/2n), where D is the distance between the reflective layer and the transflective layer, λ is a wavelength of light of a predetermined color, n is an effective refractive index of a medium between the reflective layer and the transflective layer, and j is a positive integer. It should be noted that: the effective refractive index of the medium between the reflective layer and the transflective layer refers to an effective refractive index of the layer medium (e.g., an organic layer, an organic light emitting layer, and a hole transport layer, etc.) between the reflective layer and the transflective layer. Thus, the display substrate can adjust the distance between the reflective layer and the transflective layer by adjusting the thickness of the additionally provided inorganic layer to make the distance between the reflective layer and the transflective layer satisfy the abovementioned formula; such that light of a predetermined color is enhanced while the light of other colors is weakened, thereby improving the color purity. It should be noted that: the effective refractive index of the medium between the reflective layer and the transflective layer refers to an effective refractive index of the layers (e.g., an organic layer, an organic light emitting layer, and a hole transport layer, etc.) serving as an entirety between the reflective layer and the transflective layer. For example, the effective refractive index can be measured experimentally or calculated.
(15) For example, supposing that the medium between the reflective layer and the transflective layer includes four layer structures whose thickness and refractive index respectively are respectively d1, n1; d2, n2; d3, n3; d4, n4, and the effective refractive index of the medium between the reflective layer and transflective layer can be equal to (d1.Math.n1+d2.Math.n2+d3.Math.n3+d4.Math.n4)/(d1+d2+d3+d4).
(16) For example, the predetermined color can be red, green or blue; of course, embodiments of the present disclosure include but are not limited thereto.
(17) For example, in the display substrate provided in an example of the present embodiment, as illustrated by
(18) For example, in the display substrate provided by an example of the present embodiment, as illustrated by
(19) For example, the sub pixel corresponding to the first anode structure emits red light with high color purity, the sub pixel corresponding to the second anode structure emits green light with high color purity, and the sub pixel corresponding to the third anode structure emits blue light with high color purity.
(20) For example, in a sub pixel corresponding to the first anode structure, the distance between the first reflective layer and the transflective layer can satisfy the following formula: D1=j.sub.1(λ.sub.1/2n), where D1 is the distance between the first reflective layer and the transflective layer, λ.sub.1 is the wavelength of red light, n is the effective refractive index of the medium between the first reflective layer and the transflective layer, and j.sub.1 is a positive integer. Thus, the sub pixel corresponding to the first anode structure emits red light with high color purity.
(21) For example, the wavelength of red light can be selected to be 620 nm. The effective refractive index of the medium between the first reflective layer and the transflective layer can be selected to be 1.8, and D1 can be calculated to be 172 j.sub.1 nanometers.
(22) For example, in the sub pixel corresponding to the second anode structure, the distance between the second reflective layer and the transflective layer can satisfy the following formula: D2=j.sub.2(λ.sub.2/2n), D2 is the distance between the second reflective layer and the transflective layer, λ.sub.2 is the wavelength of green light, n is the effective refractive index of the medium between the second reflective layer and the transflective layer, and j.sub.2 is a positive integer. Thus, the sub pixel corresponding to the second anode structure emits green light with high color purity.
(23) For example, the wavelength of red light can be selected to be 520 nm, and the effective refractive index of the medium between the first reflective layer and the transflective layer can be selected to be 1.8, and D2 can be calculated as 144 j.sub.2 nm.
(24) For example, in the sub pixel corresponding to the third anode structure, the distance between the third reflective layer and the transflective layer can satisfy the following formula: D3=j.sub.3(λ.sub.3/2n), wherein, D3 is the distance between the third reflective layer and the transflective layer, λ.sub.3 is the wavelength of blue light, n is the effective refractive index of the medium between the third reflective layer and the transflective layer, and j.sub.3 is a positive integer. Thus, the sub pixel corresponding to the third anode structure emits blue light with high color purity.
(25) For example, the wavelength of red light can be selected to be 460 nm, and the effective refractive index of the medium between the first reflective layer and the transflective layer can be selected to be 1.8, and D3 can be calculated as 127 j.sub.3 nm.
(26) For example, in the display substrate provided by an example of the present embodiment, as illustrated by
(27) For example, in the display substrate provided in an example of the present embodiment, as illustrated by
(28) For example, as illustrated by
(29) For example, in the display substrate provided in an example of the present embodiment, as illustrated by
(30) For example, in the display substrate provided in an example of the present embodiment, molybdenum oxide can be used as the material of the inorganic layer. On the one hand, molybdenum oxide is convenient for etching and patterning; on the other hand, molybdenum oxide can also be used as a hole injection layer, so that an additional hole injection layer is not need to be provided.
(31) For example, as illustrated by
(32)
(33) For example, as illustrated by
(34) For example, as illustrated by
(35) For example, in the display substrate provided in an example of the present embodiment, the electron stop layer, the hole transport layer, the hole stop layer, and the electron transport layer can be continuously disposed on the first anode structure, the second anode structure, and the third anode structure, respectively. That is, the electron stop layer, the hole transport layer, the hole stop layer, and the electron transport layer can be disposed on an entirety of the first anode structure, the second anode structure, and the third anode structure. As a result, the electron stop layer, the hole transport layer, the hole stop layer, and the electron transport layer can be directly formed by using an open mask without using a fine metal mask (FMM). On the one hand, the display substrate does not need to be manufactured by using a fine metal mask (FMM), which saves costs; on the other hand, the PPI of the display substrate is also relatively high.
(36) An embodiment of the present disclosure provides a manufacturing method of a display substrate.
(37) Step S201: forming an anode structure on a base substrate, the anode structure including a reflective layer and an inorganic layer disposed on a side of the reflective layer away from the base substrate.
(38) For example, the base substrate can employ a glass substrate, a quartz substrate, a plastic substrate, or other substrates.
(39) Step S202: forming a light emitting layer on a side of the anode structure away from the base substrate.
(40) For example, the light emitting layer can be an organic electroluminescent layer, and can include a plurality of sub light emitting layers, such as an orange-red light emitting layer and a blue-green light emitting layer, so as to emit white light.
(41) Step S203: forming a cathode layer on a side of the light emitting layer away from the base substrate, the cathode layer includes a transflective layer, and the inorganic layer can adjust the distance between the reflective layer and the transflective layer.
(42) For example, the cathode layer itself can be a transflective layer, or can be additionally provided with a transflective layer. The embodiments of the disclosure are not limited thereto.
(43) In the manufacturing method of the display substrate provided in the present embodiment, the reflective layer in the anode structure formed on the base substrate and the transflective layer in the cathode layer can constitute a micro cavity effect structure, and the light emitting layer disposed between the anode structure and the cathode layer can be electroluminescent. The light directly emitted by the light emitting layer and the light reflected by the reflective layer can interfere with each other in the abovementioned micro cavity effect structure; light with a specific wavelength or a specific wavelength range can enhanced by adjusting the distance between the reflective layer and the transflective layer through the inorganic layer which is additionally provided, and light with other wavelengths is weakened, so that the luminescence spectrum of the sub pixel corresponding to the anode structure can be narrowed, thereby improving the color purity. In addition, because the light emitting layer can be used for emitting white light in the manufacturing method provided by the present embodiment, the light emitting layer can be manufactured only by an open mask, without using a fine metal mask (FMM), thereby saving the processes and reducing the costs.
(44) For example, in the manufacturing method of a display substrate provided in an example of the present embodiment, the step S201 of forming an anode structure on a base substrate can include: forming a reflective layer on the base substrate by using a patterning process; and forming an inorganic layer on a side of the reflective layer away from the base substrate by using a patterning process, and an orthographic projection of the inorganic layer on the base substrate is completely overlapped with an orthographic projection of the reflective layer on the base substrate. Therefore, layers of the anode structure can be manufactured by using a mask process instead of a fine metal mask (FMM). Therefore, the number or density of the anode structures per unit area is relatively high, so that the display substrate manufactured by the manufacturing method provided by the present embodiment has a relatively high PPI. It should be noted that the abovementioned patterning process can be a masking process or a printing process, and the masking process can include steps of exposing, developing, etching, and the like.
(45) For example, the reflective layer can be formed on the base substrate by using a sputtering process and a dry etching process.
(46) For example, in the manufacturing method of a display substrate provided in an example of the present embodiment, forming an anode structure on a base substrate can include: forming a first anode structure, a second anode structure, and a third anode structure which are disposed on the base substrate at intervals, the first anode structure includes a first reflective layer and a first inorganic layer disposed on the first reflective layer, the second anode structure includes a second reflective layer and a second inorganic layer disposed on the second reflective layer, and the third anode structure includes a third reflective layer and a third inorganic layer disposed on the third reflective layer. The first inorganic layer, the second inorganic layer, and the third inorganic layer have different thicknesses. Therefore, the sub pixels corresponding to the first anode structure, the second anode structure, and the third anode structure can respectively emit different light with relatively high color purity, so that the display substrate manufactured by the manufacturing method of the display substrate provided by the present embodiment has a relatively high color gamut.
(47) For example,
(48) For example, in the manufacturing method of a display substrate provided in an example of the present embodiment, As illustrated by
(49) For example, in a case where the distance between the first reflective layer and the transflective layer is 172 j.sub.1 nanometers, the distance between the second reflective layer and the transflective layer is 144 j.sub.2 nanometers, and the distance between the third reflective layer and the transflective layer is 127 j.sub.3 nanometers. Because the distance between the first reflective layer and the transflective layer is 172 j.sub.1 nm, which is relatively large, the distance between the first reflective layer and the transflective layer can be applied as the first period, that is, j.sub.1=1; the distance between the second reflective layer and the transflective layer and the distance between the third reflective layer and the transflective layer are relatively small, they can be applied as the second period, that is, j.sub.2=2 and j.sub.3=3. If the thickness of other layers (for example, the electron stop layer, the hole transport layer, the light emitting layer, the hole stop layer, and the electron transport layer) except the inorganic layer between the reflective layer and the transflective layer is 160 nm, then it can be calculated that the thickness of the first inorganic layer is 12 nm, the thickness of the second inorganic layer is 94 nm, and the thickness of the third inorganic layer is 120 nm. Thus, the thickness of the first sub inorganic layer is 12 nanometers, the thickness of the second sub inorganic layer is 82 nanometers, and the thickness of the third sub inorganic layer is 26 nanometers.
(50) For example, in the manufacturing method of a display substrate provided in an example of the present embodiment, forming the first sub inorganic layer on a side of the first reflective layer, the second reflective layer, and the third reflective layer away from the base substrate includes: forming an inorganic material layer on a side of the reflective layer, the second reflective layer, and the third reflective layer away from the base substrate; and patterning the inorganic material layer to form a first sub inorganic layer, and an orthographic projection of the first sub inorganic layer on the base substrate is completely overlapped with an orthographic projection of the first reflective layer, the second reflective layer, and the third reflective layer on the base substrate.
(51) For example, in the manufacturing method of a display substrate provided in an example of the present embodiment, the material of the reflective layer includes aluminum or silver. Thus, the reflective layer can also serve as a reflective layer as well as an anode.
(52) For example, in the manufacturing method of a display substrate provided in an example of the present embodiment, the material of the inorganic layer includes molybdenum oxide or titanium nitride. On the one hand, molybdenum oxide is convenient for etching and patterning; on the other hand, molybdenum oxide can also be used as a hole injection layer, so that an additional hole injection layer can be not provided.
(53) An embodiment of the present disclosure provides a display device including the display substrate described in any one of the abovementioned embodiments. Therefore, the display device can have a high color gamut under the premise of guaranteeing a relatively high PPI.
(54) For example, the display device can be a micro display device such as a helmet display device and a glasses-type display device. Certainly, embodiments of the present disclosure include, but are not limited thereto, and the display device can also be an electronic device having a display function, such as: a notebook computer, a navigator, a television, a mobile phone, or the like.
(55) The following points should to be explained:
(56) (1) The accompanying drawings involve only the structure(s) in connection with the embodiment(s) of the present disclosure, and other structure(s) can be referred to common design(s).
(57) (2) In the absence of conflict, the features of the same embodiment and the different embodiments can be combined with each other.
(58) The foregoing is only the embodiments of the present invention and not intended to limit the scope of protection of the present invention, alternations or replacements which can be easily envisaged by any skilled person being familiar with the present technical field shall fall into the protection scope of the present disclosure. Thus, the protection scope of the present disclosure should be based on the protection scope of the claims.