Patent ID: 12193274

DETAILED DESCRIPTION OF THE DISCLOSURE

The embodiments of the present disclosure are described in detail below. The embodiments described below are exemplary, and are only used to explain the present disclosure, and should not be construed as limiting the present disclosure. Where specific techniques or conditions are not indicated in the embodiments, the procedures shall be carried out in accordance with the techniques or conditions described in the literature in the field or in accordance with the product specification. The reagents or instruments used without the manufacturer's indication are all conventional products that can be purchased commercially.

In one aspect of the present disclosure, a display substrate is provided. According to an embodiment of the present disclosure, referring toFIG.1, the display substrate100comprises: a first substrate11; a pixel defining layer20which is located on the first substrate11and comprises a plurality of sub-pixel openings21; and at least one recess30located on a side of the display substrate100away from the first substrate11. An orthographic projection of the at least one recess30on the first substrate11and orthographic projections of the plurality of sub-pixel openings21on the first substrate11do not overlap. Due to the recess30, when the display substrate100is assembled into a display device, the recess30can accommodate the spacers protruding on the color filter substrate. Compared to accommodating the spacers in the film layer parallel to the first substrate11, the display substrate100provided by the embodiments of the present disclosure can greatly reduce the thickness (i.e., the cell thickness) of the display device, thereby reducing the light-emitting path of the light-emitting element, improving the efficiency of light emitted by the light-emitting element, and prolonging the life of the light-emitting element.

According to the embodiments of the present disclosure, the specific method of forming the recess30is not particularly limited. Specifically, the recess30can be formed in the display substrate100by forming a groove in a certain layer or layers in the display substrate100, and the position of the layer(s) forming the groove in the display substrate100is not particularly required. It can be located on both sides of the display substrate100or in the middle of the display substrate100. In some embodiments, a groove may be formed in the insulating layer of the display substrate100. Specifically, referring toFIG.1, a base10comprises: the first substrate11; a circuit structure layer12on the first substrate11; an insulating layer13which is provided on a side of the circuit structure layer12away from the first substrate11and comprises at least one groove14; an anode15on a side of the insulating layer13away from the first substrate11, and an orthographic projection of the anode15on the first substrate11covers the orthographic projections of the sub-pixel openings21on the first substrate11, that is, the anode15is located at least in the plurality of sub-pixel openings21; a light-emitting layer16on a side of the pixel defining layer20away from the first substrate11, and an orthographic projection of the light-emitting layer16on the first substrate11covers the orthographic projections of the sub-pixel openings21on the first substrate11, that is, the light-emitting layer16is located at least in the plurality of sub-pixel openings21; and a cathode17which is arranged on a side of the light-emitting layer16away from the first substrate11, and covers a surface of the light-emitting layer16away from the first substrate11and a surface of the pixel defining layer20away from the first substrate11and not covered by the light-emitting layer16. In some embodiments, a part of the pixel defining layer20and a part of the cathode17are stacked in the groove14to form the recess30. In an alternative embodiment, a part of the pixel defining layer20, a part of the light-emitting layer16and a part of the cathode17are stacked in the groove14to form the recess30. Therefore, it has no influence on other structures of the display substrate100, and the process of forming the groove14is simple and has high compatibility with existing equipment and processes.

It should be noted that the light-emitting layer16may or may not be provided on the inner wall of the groove14, that is, the pixel defining layer20, the light-emitting layer16and the cathode17may be stacked on the inner wall of the groove14, or the pixel defining layer20and the cathode17are stacked on the inner wall of the groove14.

According to the embodiment of the present disclosure, the specific type of the first substrate11is not particularly limited, and can be flexibly selected according to actual needs. In some specific embodiments, the first substrate11may be glass, polymer, or the like.

According to an embodiment of the present disclosure, a circuit for driving the display device for display may be provided in the circuit structure layer12, and the specific circuit structure is not particularly limited, as long as the driving display can be effectively realized. In some specific embodiments, a thin film transistor (TFT) array may be provided in the circuit structure layer12. Specifically, each TFT may comprise an active layer121(the active layer121comprises a conductor portion1211and a semiconductor portion1212), a gate insulating layer122, a gate electrode123, an interlayer insulating layer124, and a source and drain electrode125. It can be understood that the TFT structure here is only an exemplary description, and is not a limitation to the embodiments of the present disclosure. For example, the TFT may also be a bottom gate structure, a back channel etch structure (BCE), an etch stop layer structure (ESL), etc., which will not be repeated here.

Specifically, the material of the insulating layer (the gate insulating layer122and the interlayer insulating layer124) in the circuit structure layer12may be silicon oxide, silicon nitride, etc., which has a good insulating effect. The material of the active layer121may be an oxide semiconductor material (such as amorphous indium gallium zinc oxide (a-IGZO), nitrogen-doped zinc oxide (ZnON), indium tin-doped zinc oxide (IZTO), silicon material (such as low temperature polysilicon, amorphous silicon) and organic materials (such as hexathiophene and polythiophene), etc., which can be selected according to specific requirements. The material of the gate electrode123and the source and drain electrodes125can be metals or alloys, for example, Ag, Cu, Al, Mo, etc., or multilayer metals such as Mo/Cu/Mo, etc., or alloy materials of the above metals, such as AlNd, MoNb etc.

According to an embodiment of the present disclosure, the insulating layer13may have a single-layer structure or a multilayer structure. In some embodiments, referring toFIG.1, the insulating layer13comprises a passivation layer131and a first flat layer132that are stacked, the passivation layer131is disposed close to the circuit structure layer12, and the bottom of the groove14may be located in the first flat layer132(refer to the display substrate100ofFIG.1), or may be located at an interface between the first planarization layer132and the passivation layer131(refer to the display substrate2000ofFIG.2), or may be located in the passivation layer131(refer toFIG.3of the display substrate300). Disposing a part of the pixel defining layer20and the cathode17(and optionally the light-emitting layer16) in the groove14to form the recess30, in this way, the recess30can be formed by using the existing structure in the display substrate100, which facilitates the simplification of the structure, and has no influence on other structures in the display substrate100.

The material of the insulating layer13is not particularly limited. In some embodiments, the material of the passivation layer131may be silicon oxide, silicon nitride, etc., and the material of the first flat layer132may be resin, such as polymethylmethacrylate, polycarbonate, polyimide and so on.

According to an embodiment of the present disclosure, referring toFIG.2, the anode15is electrically connected to the thin film transistor in the circuit structure layer12through a via hole133(specifically, the anode15can be electrically connected to the source and drain electrode125in the thin film transistor), and the via hole133penetrates the groove14. Specifically, the via hole133may be formed at the bottom of the groove14. Further, referring toFIG.2, the anode15may cover a part of the bottom of the groove14. As a result, the thickness of the film that needs to be penetrated to form the via hole133is thinner, the processing time can be shortened, the cost is reduced, and the structure is more compact, which is beneficial for the improvement of the resolution of the display device.

Specifically, the material of the anode15can be metal, alloy or transparent conductive oxide, which can be specifically selected according to actual needs. In some embodiments, the display substrate100is used in a bottom emission display device, and the anode15needs a certain transmittance to ensure that light is emitted for display. In this case, the material of the anode15can be thinner metal, alloy or transparent conductive oxide. In an alternative embodiment, the display substrate100is used in a top emission display device, and the material of the anode15is not particularly limited. In this case, a metal or an alloy can be used for better conductivity, the metal or alloy includes but is not limited to Ag, Cu, Al, Mo, multilayer metals such as Mo/Cu/Mo, alloy materials of the above metals such as AlNd, MoNb, a stack structure (such as Mo/AlNd/ITO) formed by metal and transparent conductive oxide (such as ITO (indium tin oxide), AZO (aluminum-doped zinc oxide)).

According to the embodiments of the present disclosure, according to the needs of different display colors, the light-emitting layer16may be a continuous whole-layer structure (in the drawings herein, the light-emitting layer16is a continuous whole-layer structure as an example), or may be a plurality of light-emitting sub-layers arranged at intervals, and each light-emitting sub-layer is arranged corresponding to one sub-pixel opening21. Specifically, when the display device is a monochrome display, the light-emitting layer16may be a whole-layer structure, or may be a plurality of light-emitting sub-layers arranged at intervals; when the display device is a color display, it is necessary to provide the light-emitting layer16with different colors, and the light-emitting layer16is a plurality of light-emitting sub-layers arranged at intervals. It should be noted here that when the light-emitting layer16has a whole-layer structure, the pixel defining layer20, the light-emitting layer16and the cathode17are stacked in the groove14; and when the light-emitting layer16is a plurality of light-emitting sub-layers arranged at intervals, all the light-emitting layer16, a part of the light-emitting layer16, or none of the light-emitting layer16may be provided in the groove14.

According to the embodiment of the present disclosure, the cathode17may have a whole-layer structure, thus, the display effect is not affected, and the preparation is convenient. The material of the cathode17may be metal, alloy or transparent conductive oxide. Specifically, when the display substrate is used in a bottom emission display device, there is no requirement for the transmittance of the cathode17, and a metal or alloy with better conductivity can be selected. When the display substrate is used in a top emission display device, the transmittance of the cathode17is required to be high, and transparent conductive oxide materials (such as AZO, IZO, etc.) and thinner metal materials selected from at least one of Mg, Ag, Ca, Sm, Al and Ba (e.g. composite materials such as Mg/Ag, Ca/Ag, Sm/Ag, Al/Ag, Ba/Ag) are needed.

According to an embodiment of the present disclosure, referring toFIGS.1to3, in the thickness direction of the display substrate, that is, in the direction perpendicular to the first substrate11, the orthographic projection of the recess30on the first substrate11at least partially overlaps with the orthographic projection of the thin film transistor in the circuit structure layer12on the first substrate11. In this way, the recess30is disposed in the non-aperture area of the display substrate, and will not affect the light emission of the light-emitting element, which can effectively improve the aperture ratio and light emission efficiency, which is beneficial to improve the resolution and display quality. It should be noted that the “non-open area of the display substrate” refers to the area in the display substrate through which the light emitted by the light-emitting element cannot transmit, for example, the position where the thin film transistors and storage capacitors are located, the “open area of the display substrate” refers to the area in the display substrate through which the light emitted by the light-emitting element can effectively transmit. The ratio of the effective light-transmitting area to the total area of the display substrate is the aperture ratio of the display substrate.

According to an embodiment of the present disclosure, the number of the recesses30may be multiple, and the multiple recesses30are substantially uniformly distributed on the display substrate. In some embodiments, one to eight (specifically, one, two, three, four, five, six, seven, or eight) sub-pixel openings21are correspondingly provided with one recess30. In other words, one recess30is arranged between every 1 to 8 sub-pixel openings21. Therefore, when the display substrate and the color filter substrate are pressed together, the display substrate can be better matched with the spacer. The substantially uniform distribution of the recesses30can make the stress uniformly distributed, which is beneficial to improve the stability and use effect of the display device.

According to another aspect of the present disclosure, a display device is provided. Referring toFIG.4, the display device400comprises: the display substrate100,2000,300described in any of the previous embodiments (FIG.4takes the display substrate100as an example); and a color filter substrate200opposite to the display substrate100. The color filter substrate200comprises at least one spacer204protruding toward the display substrate100, the at least one spacer204corresponds to the at least one recess30in a one-to-one correspondence, and at least a part of each spacer204is received in a corresponding recess30. By receiving the protruding spacers204in the recesses30, the distance between the display substrate100and the color filter substrate200can be reduced, thereby helping to reduce the thickness of the display device400, thereby reducing the distance between the light-emitting layer106and the light-emitting surface of the display device400, shortening the light-emitting path of the light-emitting layer106, improving the light-emitting efficiency, and prolonging the lifetime.

According to an embodiment of the present disclosure, referring to the display device500illustrated inFIG.5, in some embodiments, an auxiliary electrode205is provided between the protruding end206of the spacer204and the recess30. The auxiliary electrode205is electrically connected to the cathode17of the display substrate100. As a result, the resistance of the cathode17can be greatly reduced. Especially when the display device500is a top emission display device, the cathode17is generally formed of a transparent conductive oxide and has a relatively high resistance in order to ensure the light transmission effect. In this case, the arrangement of the auxiliary electrode205can greatly reduce the resistance of the cathode17and improve the use effect of the display device500.

Continuing to refer toFIG.5, the distance between the auxiliary electrode205and the first substrate101is a first distance S1, and the distance between the portion of the light-emitting layer16of the display substrate100located in the sub-pixel openings21and the first substrate11is a second distance S2. The first distance S1is smaller than the second distance S2, that is, the auxiliary electrode205is disposed under the portion of the light-emitting layer16located in the sub-pixel openings21. As a result, the light emitted from the light-emitting layer16is prevented from being reflected by the auxiliary electrode205, and the pixel light leakage and the TFT being irradiated by the internal reflected light of the display device500are avoided, and the stability of the display device500can be effectively improved.

According to an embodiment of the present disclosure, the material of the auxiliary electrode205may comprise at least one of Mo, Al, Ti, Au, Cu, Hf, Ta, Nd, and alloys thereof. Specifically, the alloy may be AlNd, MoNb, and the like. Further, the auxiliary electrode205may have a single-layer structure or a multilayer structure, and specifically may be a multilayer metal, such as MoNb/Cu/MoNb, AlNd/Mo/AlNd, and the like.

According to an embodiment of the present disclosure, referring toFIG.5, the color filter substrate200may further include: a second substrate201; a filter layer202which is provided on the second substrate201and comprises a color filter2021and a black matrix2022; a second flat layer203which is provided on a side of the filter layer202away from the second substrate201. The spacer204is located on a side of the second flat layer203away from the second substrate201and is integrally formed with the second flat layer203. In other words, the spacer204and the second flat layer203can be formed at the same time by patterning the same film layer. Therefore, the display device500is easy to prepare, the spacer204does not fall off, and the stability of the display device500is better.

In some embodiments, the material of the second flat layer203and the spacer204may comprise at least one of resin, spin on glass (SOG), and benzocyclobutene (BCB).

According to another aspect of the present disclosure, there is provided a method of preparing the display device described in any of the foregoing embodiments. The method can comprise the following steps:

S10: forming a display substrate comprising at least one recess.

Specifically, in this step, referring toFIG.6, forming a display substrate may comprise: (a) sequentially forming a circuit structure layer12and an insulating material layer18on the first substrate11; (b) patterning the insulating material layer18to form an insulating layer13comprising at least one groove14, the insulating layer13comprising a passivation layer131and a first flat layer132; (c) sequentially forming an anode15and a pixel defining layer20on a side of the insulating layer13away from the first substrate11; (d) sequentially forming a light-emitting layer16and a cathode17on a side of the pixel defining layer20away from the first substrate11. In some embodiments, a part of the pixel defining layer20and a part of the cathode17are stacked on the inner wall of the groove14to form the recess30. In an alternative embodiment, a part of the pixel defining layer20, a part of the light-emitting layer16and a part of the cathode17are stacked on the inner wall of the groove14to form the recess30.

Specifically, the specific formation method of each layer structure in the circuit structure layer12is not particularly limited, and it can be specifically selected according to needs. For example, the entire insulating layer13, the light-emitting layer16, and the cathode17can be directly formed by vapor deposition (specifically, physical vapor deposition (vacuum evaporation, magnetron sputtering, etc.), chemical vapor deposition, etc.). The patterned active layer, gate electrode, gate insulating layer, source and drain electrodes, anode, and pixel defining layer can be first formed into a whole layer structure by vapor deposition method, and then patterned by etching with a mask.

S20: forming a color filter substrate comprising at least one spacer, the at least one spacer corresponding to the at least one recess in a one-to-one correspondence.

Specifically, in this step, referring toFIG.7, forming a color filter substrate may comprise: (e) forming a filter layer202on the second substrate201; (f) applying a flat layer on a side of the filter layer202away from the second substrate201, and patterning the flat layer to form a second flat layer203and the spacer204at the same time.

Specifically, forming the filter layer202may comprise the steps of forming a color filter2021and a black matrix2022. Specifically, the black matrix2022and the color filter2021can be successively deposited on the second substrate201. When the color filter2021is prepared, red, green, and blue filters are successively deposited, and the color filter2021covers a part of the black matrix2022.

In some embodiments, referring toFIG.7, forming the color filter substrate202may further comprise: (g) forming an auxiliary electrode205at a protruding end206on a side of the spacer204away from the second substrate201. Specifically, a metal layer can be deposited and patterned to form the auxiliary electrode205.

S30: assembling the display substrate and the color filter substrate so as to make at least a part of each spacer204to be received in a corresponding recess30.

In this step, the specific assembling process can be performed with reference to conventional techniques, and the spacer204and the recess30can be aligned during positioning and alignment.

In a specific embodiment, the display device can be prepared by the following steps:(1) cleaning the second substrate201, and successively depositing the black matrix2022and the color filter layer2021on the second substrate201. When the color filter layer2021is prepared, the red, green and blue filters are successively deposited, and the color filter2021covers a part of the black matrix2022;(2) integrally forming the second flat layer203and the spacer204. Specifically, an entire layer structure can be deposited and then patterned to form the second flat layer203and the spacer204;(3) depositing a metal layer on a side of the spacer204away from the second substrate201, and patterning the metal layer to form the auxiliary electrode205, as illustrated inFIG.7(g);(4) forming an active layer pattern on the first substrate101after initial cleaning of the first substrate101;(5) successively depositing a gate insulating layer and a gate layer, and using a mask to form the gate electrode123and the gate insulating layer122by dry etching using a self-aligned process, and when the gate insulating layer122is dry-etched, performing over-etching to realize the conductorization of the active layer;(6) depositing the interlayer insulating layer and forming via holes;(7) depositing and patterning source and drain metals;(8) depositing and patterning a passivation layer and a first flat layer, and forming a groove14in the first flat layer132;(9) depositing and patterning the anode, and depositing and patterning the pixel defining layer;(10) evaporating the light-emitting layer and cathode;(11) assembling the display substrate and the color filter substrate.

The method is simple to operate, easy to control, high compatibility with existing equipment. The resulted display device has a thinner thickness, hence the distance between the light-emitting element and the light-emitting surface of the display device is short, and hence the light-emitting element has a short light-emitting distance, an improved light-emitting efficiency, and a long lifetime.

In the description of the embodiments of the present disclosure, it should be understood that the terms “first” and “second” are only used for descriptive purposes, which cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined with “first” and “second” may explicitly or implicitly include one or more of these features. In the description of the embodiments of the present disclosure, the term “a plurality of” means two or more than two, unless otherwise specifically defined.

In the description of this specification, descriptions with reference to the terms “one embodiment”, “some embodiments”, “examples”, “specific examples”, or “some examples” etc. mean specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine different embodiments or examples and the features of different embodiments or examples described in this specification without contradicting each other.

Although the embodiments of the present disclosure have been illustrated and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above-mentioned embodiments within the scope of the present disclosure, and these changes, modifications, substitutions and variations should all be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.