CN111785852B - Display substrate, manufacturing method thereof, display panel and display device - Google Patents
Display substrate, manufacturing method thereof, display panel and display device Download PDFInfo
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- CN111785852B CN111785852B CN202010721807.XA CN202010721807A CN111785852B CN 111785852 B CN111785852 B CN 111785852B CN 202010721807 A CN202010721807 A CN 202010721807A CN 111785852 B CN111785852 B CN 111785852B
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/80—Constructional details
- H10K50/805—Electrodes
- H10K50/82—Cathodes
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/60—OLEDs integrated with inorganic light-sensitive elements, e.g. with inorganic solar cells or inorganic photodiodes
- H10K59/65—OLEDs integrated with inorganic image sensors
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
Abstract
The invention discloses a display substrate, a manufacturing method thereof, a display panel and a display device, wherein the thickness of a second cathode part positioned in a transmission area in a cathode is set to be smaller than that of a first cathode part positioned in a connection area in the cathode.
Description
Technical Field
The present invention relates to the field of display technologies, and in particular, to a display substrate, a manufacturing method thereof, a display panel, and a display device.
Background
Currently, a full-screen is a main direction of development of an Organic Light-Emitting Diode (OLED) display technology, and in the existing OLED technical scheme, the cathode (usually Mg: ag material) is patterned to improve the transmittance, so that the full-screen display and the under-screen camera shooting are achieved at the same time, and the full-screen display and under-screen camera shooting have extremely important roles. However, the patterned cathode has an increased resistance compared to the entire cathode, and the IR drop phenomenon is also remarkable, which requires an increased driving voltage to compensate for the brightness of the organic functional layer.
Disclosure of Invention
The embodiment of the invention provides a display substrate, a manufacturing method thereof, a display panel and a display device, which are used for improving the transmittance of a cathode on the basis of not increasing the resistance of the cathode.
Accordingly, an embodiment of the present invention provides a display substrate including:
a substrate including a plurality of sub-pixels;
a pixel defining layer on the substrate, the pixel defining layer including a plurality of pixel openings; wherein one of the subpixels comprises one of the pixel openings;
a cathode which is positioned on one side of the pixel defining layer, which is away from the substrate base plate; the orthographic projection of the cathode on the substrate covers the orthographic projection of the pixel opening on the substrate, and the orthographic projection of the cathode on the substrate overlaps the orthographic projection of the pixel defining layer on the substrate;
wherein the pixel defining layer has a connection region and a transmission region, and a portion of the cathode overlapping the pixel defining layer includes a first cathode portion and a second cathode portion; the first cathode part is positioned in the connecting area and has a first thickness; the second cathode part is positioned in the transmission area and has a second thickness; the second thickness is less than the first thickness.
Optionally, in the display substrate provided in the embodiment of the present invention, a portion of the cathode covering the pixel opening is a third cathode portion, and the third cathode portion has a third thickness, where the third thickness is smaller than the first thickness.
Optionally, in the display substrate provided by the embodiment of the present invention, the second thickness is not greater than the third thickness.
Optionally, in the display substrate provided in the embodiment of the present invention, the connection region is located between the pixel opening and the transmission region, or the transmission region is located between the pixel opening and the connection region.
Optionally, in the display substrate provided by the embodiment of the present invention, regions between the partially adjacent pixel openings are all the transmission regions, and regions between the partially adjacent pixel openings are all the connection regions.
Optionally, in the display substrate provided by the embodiment of the invention, the first thickness is 30nm-60nm, and the third thickness is 3nm-6nm.
Correspondingly, the embodiment of the invention also provides a display panel which comprises the display substrate provided by the embodiment of the invention.
Correspondingly, the embodiment of the invention also provides a display device which comprises the display panel provided by the embodiment of the invention.
Correspondingly, the embodiment of the invention also provides a manufacturing method of the display substrate, which comprises the following steps:
forming a pixel defining layer on a substrate having a plurality of sub-pixels; wherein the pixel defining layer includes a plurality of pixel openings, one of the sub-pixels including one of the pixel openings;
forming a cathode on one side of the pixel defining layer away from the substrate base plate; wherein the orthographic projection of the cathode on the substrate covers the orthographic projection of the pixel opening on the substrate, and the orthographic projection of the cathode on the substrate overlaps the orthographic projection of the pixel defining layer on the substrate, wherein the pixel defining layer has a connection region and a transmission region, and a portion of the cathode overlapping the pixel defining layer includes a first cathode portion and a second cathode portion; the first cathode part is positioned in the connecting area and has a first thickness; the second cathode part is positioned in the transmission area and has a second thickness; the second thickness is less than the first thickness.
Optionally, in the above manufacturing method provided by the embodiment of the present invention, forming a cathode on a side of the pixel defining layer facing away from the substrate specifically includes:
forming a sacrificial layer on one side of the pixel defining layer away from the substrate base plate;
forming a photoresist layer on one side of the sacrificial layer, which is away from the substrate;
exposing and developing the photoresist layer to remove the photoresist in the connecting area;
developing the sacrificial layer, and forming a T-shaped stripping column formed by the photoresist layer and the sacrificial layer at the pixel opening and in the transmission region;
evaporating a first cathode film layer on a substrate base plate with the T-shaped stripping column, wherein the first cathode film layer is broken at the T-shaped stripping column; wherein the thickness of the first cathode film layer is 30nm-60nm;
stripping the "T" shaped stripper column;
evaporating a second cathode film layer on the substrate with the stripped T-shaped stripping column, wherein the thickness of the second cathode film layer is 3-6 nm so as to form a third cathode part at the pixel opening, form a first cathode part at the connecting region and form a second cathode part at the transmitting region; wherein the first cathode portion, the second cathode portion, and the third cathode portion constitute the cathode.
Optionally, in the above manufacturing method provided by the embodiment of the present invention, forming a cathode on a side of the pixel defining layer facing away from the substrate specifically includes:
evaporating a first cathode film layer on one side of the pixel limiting layer, which is away from the substrate; the thickness of the first cathode film layer is 3nm-6nm;
forming a sacrificial layer on the substrate base plate with the first cathode film layer formed thereon;
forming a photoresist layer on one side of the sacrificial layer, which is away from the substrate;
exposing and developing the photoresist layer to remove the photoresist in the connecting area;
developing the sacrificial layer, and forming a T-shaped stripping column formed by the photoresist layer and the sacrificial layer at the pixel opening and in the transmission region;
evaporating a second cathode film layer on the substrate base plate with the T-shaped stripping column, wherein the second cathode film layer is broken at the T-shaped stripping column; wherein the thickness of the second cathode film layer is 30nm-60nm;
stripping the T-shaped stripping column to form a third cathode part at the pixel opening, a first cathode part at the connection region, and a second cathode part at the transmission region; wherein the first cathode portion, the second cathode portion, and the third cathode portion constitute the cathode.
Optionally, in the above manufacturing method provided by the embodiment of the present invention, forming a cathode on a side of the pixel defining layer facing away from the substrate specifically includes:
forming a first sacrificial layer on one side of the pixel defining layer away from the substrate base plate;
forming a first photoresist layer on one side of the first sacrificial layer, which is away from the substrate;
exposing and developing the first photoresist layer to remove the first photoresist in the connecting area;
developing the first sacrificial layer, and forming a first T-shaped stripping column formed by the first photoresist layer and the first sacrificial layer at the pixel opening and in the transmission region;
evaporating a first cathode film layer on a substrate base plate with the first T-shaped stripping column formed, wherein the first cathode film layer is disconnected at the first T-shaped stripping column; wherein the thickness of the first cathode film layer is 30nm-60nm;
stripping the first "T" shaped stripper column;
forming a second sacrificial layer on the substrate base plate from which the first T-shaped stripping column is stripped;
forming a second photoresist layer on one side of the second sacrificial layer away from the substrate base plate;
exposing and developing the second photoresist layer to remove the second photoresist at the connection region and the pixel opening;
developing the second sacrificial layer, and forming a second T-shaped stripping column formed by the second photoresist layer and the second sacrificial layer in the transmission region;
evaporating a second cathode film layer on the substrate base plate with the second T-shaped stripping column, wherein the second cathode film layer is disconnected at the second T-shaped stripping column; wherein the thickness of the second cathode film layer is 3nm-6nm;
stripping the second T-shaped stripping column to form a third cathode part at the pixel opening and a first cathode part at the connection region; the first cathode portion and the third cathode portion constitute the cathode.
The embodiment of the invention has the following beneficial effects:
according to the display substrate, the manufacturing method thereof, the display panel and the display device, the thickness of the second cathode part positioned in the transmission area in the cathode is set to be smaller than the thickness of the first cathode part positioned in the connection area in the cathode, compared with the scheme that the thicknesses of the cathodes at all positions in the related art are the same, the thickness of the second cathode part positioned in the transmission area in the cathode can be made to be thinner than the thickness of the cathode at the position of the transmission area in the related art, and the thickness of the first cathode part positioned in the connection area in the cathode can be made to be thicker than the thickness of the cathode at the position of the connection area in the related art, so that the scheme of the invention does not increase the cathode resistance in the whole, can improve the transmittance of the transmission area, and can improve the shooting performance under the OLED screen.
Drawings
FIG. 1 is a schematic cross-sectional view of a display substrate according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a cross-sectional structure of a display substrate according to an embodiment of the invention;
FIG. 3 is a schematic diagram of a third cross-sectional structure of a display substrate according to an embodiment of the present invention;
FIG. 4 is a flowchart of a method for manufacturing a display substrate according to an embodiment of the present invention;
FIGS. 5A to 5I are schematic cross-sectional structures of the display substrate shown in FIG. 1 after performing steps according to an embodiment of the present invention;
fig. 6A to 6G are schematic cross-sectional structures of the display substrate shown in fig. 2 after performing steps according to an embodiment of the present invention;
fig. 7A to 7F are schematic cross-sectional structures of the display substrate shown in fig. 3 after performing steps according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a display device according to an embodiment of the present invention.
Detailed Description
In order to make the technical solution and advantages of the present invention more clear, the following describes in detail specific embodiments of a display substrate, a manufacturing method thereof, a display panel and a display device provided in the embodiments of the present invention with reference to the accompanying drawings.
The thickness and shape of the films in the drawings do not reflect the true proportions of the display substrate, and are intended to illustrate the present invention only.
One common method of increasing the cathode transmittance in the related art is to pattern the cathode, i.e., selectively remove the cathode in the non-pixel area of the existing product. However, the patterned cathode has an increased resistance compared to the entire cathode, and the IR drop phenomenon is also remarkable, which requires an increased driving voltage to compensate for the brightness of the organic functional layer. One way to solve the above problem is to increase the thickness of the cathode, so that the cathode resistance after patterning is equivalent to the cathode resistance of the whole surface in the existing product, but the increase of the cathode thickness can seriously affect the light-emitting efficiency of the organic functional layer.
In view of this, an embodiment of the present invention provides a display substrate, as shown in fig. 1-3, including:
a substrate 1 including a plurality of sub-pixels, fig. 1 to 3 illustrate one sub-pixel as an example;
a pixel defining layer 2 on the substrate 1, the pixel defining layer 2 including a plurality of pixel openings 21; wherein one sub-pixel includes one pixel opening 21;
a cathode 3 located on a side of the pixel defining layer 2 facing away from the substrate 1; the front projection of the cathode 3 onto the substrate 1 covers the front projection of the pixel opening 21 onto the substrate 1, and the front projection of the cathode 3 onto the substrate 1 overlaps the front projection of the pixel defining layer 2 onto the substrate 1;
wherein the pixel defining layer 2 has a connection region 01 and a transmission region 02, and a portion of the cathode 3 overlapping the pixel defining layer 2 includes a first cathode portion 31 and a second cathode portion 32; the first cathode portion 31 is located in the connection region 01, and the first cathode portion 31 has a first thickness d1; the second cathode portion 32 is located in the transmission region 02, and the second cathode portion 32 has a second thickness d2; the second thickness d2 is smaller than the first thickness d1.
In the display substrate provided by the embodiment of the invention, by setting the thickness d2 of the second cathode portion 32 located in the transmission region 02 in the cathode 3 to be smaller than the thickness d1 of the first cathode portion 31 located in the connection region 01 in the cathode 3, compared with the scheme that the thicknesses of the cathodes at all positions in the related art are the same, the invention can make the thickness d2 of the second cathode portion 32 located in the transmission region 02 in the cathode 3 thinner than the cathode at the position of the transmission region in the related art, and make the thickness d1 of the first cathode portion 31 located in the connection region 01 in the cathode 3 thicker than the cathode at the position of the connection region in the related art, so that the scheme of the invention does not increase the cathode resistance as a whole, and can improve the transmittance of the transmission region, thereby improving the performance of the under-screen image capturing of the full-screen OLED.
The structures of fig. 1 and 2 are the same, and fig. 1 and 2 are different from each other in order to illustrate the method of manufacturing the cathode 3.
In a specific implementation, in the display substrate provided by the embodiment of the present invention, as shown in fig. 1 to fig. 3, the display substrate further includes: the thin film transistor between the substrate 1 and the pixel defining layer 2, the invention only illustrates the drain electrode 4 of the thin film transistor, the flat layer 5 on the side of the drain electrode 4 facing away from the substrate 1, the anode 6 on the side of the flat layer facing away from the substrate 1, the pixel defining layer 2 covering part of the anode 6 and exposing part of the anode 6, and the organic functional layer 7 between the anode 6 and the cathode 3; wherein the drain electrode 4 of the thin film transistor is electrically connected to the anode electrode 6 through a via hole penetrating the planarization layer 5.
It should be noted that fig. 1 to 3 are provided only for illustrating the structure of the cathode 3 according to the embodiment of the present invention, and of course, the display substrate further includes other functional layers known to those skilled in the art, which are not listed herein.
In a specific implementation, in order to improve the light emitting efficiency of the sub-pixel, in the display substrate provided in the embodiment of the present invention, as shown in fig. 1 to 3, a portion of the cathode 3 covering the pixel opening 21 is a third cathode portion 33, where the third cathode portion 33 has a third thickness d3, and the third thickness d3 is smaller than the first thickness d1. Specifically, the thickness d3 of the third cathode portion 33 covering the pixel opening 21 in the cathode 3 can be made thinner than the cathode at the pixel opening position in the related art, so that the luminous efficiency of the organic functional layer in the sub-pixel can be improved, therefore, the embodiment of the invention can realize the distribution of the thickness difference of the cathode 3 in different areas by patterning the cathode 3 on the basis of not increasing the overall resistance of the cathode 3, and can simultaneously improve the transmittance of the transmission area 02 and the luminous efficiency of the organic functional layer in the sub-pixel, so as to improve the imaging performance under the whole screen and the coverage performance.
In a specific implementation, in the display substrate provided by the embodiment of the invention, the second thickness of the second cathode portion is not greater than the third thickness of the third cathode portion. Specifically, as shown in fig. 1 and 2, the second thickness d2 of the second cathode portion 32 and the third thickness d3 of the third cathode portion 33 may be the same; as shown in fig. 3, the second thickness d2 of the second cathode portion 32 may be 0, that is, the cathode material is not provided in the transmissive region 02, so that the transmittance of the transmissive region 02 may be increased, and the under-screen image capturing performance of the full-screen may be further improved.
It should be noted that, the protection content of the embodiment of the present invention is not limited to the structure of fig. 1-3, and compared with the cathode scheme in the prior art, the present invention is capable of achieving the distribution of the cathode thickness difference in different areas by patterning the cathode without increasing the overall resistance of the cathode, for example, the connection area and the transmission area may both have cathode materials, and the thicknesses are set to be different, which falls within the protection scope of the present invention.
In practical implementation, in the display substrate provided by the embodiment of the present invention, as shown in fig. 1 to 3, the connection region 01 is located between the pixel opening 21 and the transmission region 02; of course, in implementation, the transmissive region 02 may also be located between the pixel opening 21 and the connection region 01.
In a specific implementation, in the display substrate provided by the embodiment of the present invention, the regions between the partially adjacent pixel openings may be all set as the transmission regions, and the regions between the partially adjacent pixel openings may be all set as the connection regions. Thus, the transmittance of the transmission region and the luminous efficiency of the organic functional layer in the sub-pixel can be improved without increasing the resistance of the cathode as a whole.
In a specific implementation, in the display substrate provided by the embodiment of the present invention, as shown in fig. 1 to 3, the first thickness d1 of the first cathode portion 31 may be 30 to 60nm, and the third thickness d3 of the third cathode portion 33 may be 3 to 6nm. Thus, as shown in FIGS. 1 to 2, the second thickness d2 of the second cathode portion 32 is 3 to 6nm; as shown in fig. 3, the second thickness d2 of the second cathode portion 32 is 0nm, i.e., no cathode material is provided in the transmission region 02.
In summary, the structure of the cathode in the embodiment of the invention has the following advantages compared with the structure of the cathode in the related art:
(1) The transmittance of the cathode can be effectively improved by removing or thinning the cathode in the permeation area;
(2) By increasing the thickness of the cathode in the connecting region, the IR drop phenomenon generated by cathode patterning (resistance increase) can be effectively solved;
(3) By reducing the thickness of the cathode in the pixel opening area, the absorption of the cathode to the light emitted by the organic functional layer can be reduced, and the light emitting efficiency of the organic functional layer can be increased.
Based on the same inventive concept, the embodiment of the invention also provides a manufacturing method of the display substrate, as shown in fig. 4, including:
s401, forming a pixel limiting layer on a substrate base plate with a plurality of sub-pixels; wherein the pixel defining layer includes a plurality of pixel openings, and one sub-pixel includes one pixel opening;
s402, forming a cathode on one side of the pixel defining layer, which is away from the substrate; wherein the front projection of the cathode on the substrate covers the front projection of the pixel opening on the substrate, and the front projection of the cathode on the substrate overlaps the front projection of the pixel defining layer on the substrate, wherein the pixel defining layer has a connection region and a transmission region, and the part of the cathode overlapping the pixel defining layer comprises a first cathode part and a second cathode part; the first cathode part is positioned in the connecting area and has a first thickness; the second cathode part is positioned in the transmission area and has a second thickness; the second thickness is less than the first thickness.
According to the manufacturing method of the display substrate provided by the embodiment of the invention, the thickness of the second cathode part positioned in the transmission area in the cathode is set to be smaller than the thickness of the first cathode part positioned in the connection area in the cathode, compared with the scheme that the thicknesses of the cathodes at all positions in the related art are the same, the thickness of the second cathode part positioned in the transmission area in the cathode can be made thinner than the thickness of the cathode at the position of the transmission area in the related art, and the thickness of the first cathode part positioned in the connection area in the cathode is made thicker than the thickness of the cathode at the position of the connection area in the related art, so that the scheme of the invention does not increase the cathode resistance in the whole and can improve the transmittance of the transmission area, and therefore, the performance of the under-screen image capturing of the full-screen OLED can be improved.
The following describes in detail a method for manufacturing the display substrate shown in fig. 1 to 3 according to an embodiment of the present invention through specific embodiments.
The detailed process of fabricating the display substrate shown in fig. 1 is as follows:
(1) A thin film transistor (only a drain electrode 4 is illustrated), a planarization layer 5, an anode electrode 6, and a pixel defining layer 2 are sequentially formed on a substrate 1, as shown in fig. 5A; wherein the pixel defining layer 2 has a plurality of pixel openings 21 exposing the anode electrode 6;
(2) An organic functional layer 7 is manufactured by adopting an evaporation mode on the basis of the step (1), as shown in fig. 5B; wherein the organic functional layer 7 may include a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and the like;
(3) Coating a layer of sacrificial layer material with the thickness of 0.5-1.5 mu m on the side, away from the substrate 1, of the pixel defining layer 2 by adopting a gluing process on the basis of the step (2), and then forming a sacrificial layer 10 by adopting a pre-baking process (the post-baking temperature is less than or equal to 90 ℃), as shown in fig. 5C;
(4) Coating a layer of negative photoresist material with the thickness of 1.5-2.5 mu m on the side, away from the substrate 1, of the sacrificial layer 10 by adopting a gluing process on the basis of the step (3), and then forming a photoresist layer 20 by adopting a pre-baking process (the post-baking temperature is less than or equal to 90 ℃), as shown in fig. 5D;
(5) On the basis of step (4), exposing the photoresist layer 20, wherein the exposure area comprises the pixel opening 21 and the transmission area 02, then developing the photoresist layer 20, and since the photoresist is negative, the exposed photoresist layer 20 is left on the substrate after development to remove the photoresist of the connection area 01, as shown in fig. 5E;
(6) On the basis of the step (5), developing the sacrificial layer 10, wherein the sacrificial layer 10 is transversely retracted during the developing process, and a T-shaped stripping column formed by the photoresist layer 20 (the residual part after developing) and the sacrificial layer 10 (the residual part after developing) is formed at the pixel opening 21 and the transmission region 02, as shown in fig. 5F;
it should be noted that, since the external water vapor may erode the organic functional layer 7 to cause the performance failure, the performance of the organic functional layer 7 may be improved more advantageously when the steps (3) - (6) are performed in a nitrogen box.
(7) Placing the structure obtained in the step (6) in an evaporation chamber, evaporating a first cathode film layer 30 on the substrate 1 with the T-shaped stripping column formed thereon, and breaking the first cathode film layer 30 at the T-shaped stripping column, as shown in FIG. 5G; the thickness of the first cathode film layer 30 may be 30nm-60nm to reduce the resistance of the cathode in the connection region 02;
(8) Taking out the structure obtained in the step (7) from the evaporation chamber, transferring to a nitrogen tank, placing the structure obtained in the step (7) in stripping liquid, dissolving the sacrificial layer 10 in the T-shaped stripping column in the stripping liquid, and stripping from the substrate 1, and simultaneously, stripping the cathode material on the T-shaped stripping column from the substrate 1 together, as shown in fig. 5H, so that the pixel opening 21 and the cathode material of the transmission region 02 are stripped, as shown in fig. 5I;
(9) Placing the structure obtained in step (8) in an evaporation chamber, evaporating a second cathode film layer 40 on the substrate 1 from which the T-shaped stripping column is stripped, wherein the thickness of the second cathode film layer 40 can be 3nm-6nm, so as to form a third cathode part 33 at the pixel opening 21, form a first cathode part 31 at the connection region 01, and form a second cathode part 32 at the transmission region 02; wherein the first cathode part 31, the second cathode part 32 and the third cathode part 33 constitute a cathode 3 as shown in fig. 1.
The detailed process of fabricating the display substrate shown in fig. 2 is as follows:
(1) A thin film transistor (only a drain electrode 4 is illustrated), a planarization layer 5, an anode electrode 6, and a pixel defining layer 2 are sequentially formed on a substrate 1, as shown in fig. 5A; wherein the pixel defining layer 2 has a plurality of pixel openings 21 exposing the anode electrode 6;
(2) An organic functional layer 7 is manufactured by adopting an evaporation mode on the basis of the step (1), as shown in fig. 5B; wherein the organic functional layer 7 may include a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and the like;
(3) In the evaporation chamber, a first cathode film layer 30 is evaporated on the side of the pixel defining layer 2 away from the substrate 1, as shown in fig. 6A; wherein, the thickness of the first cathode film layer 30 can be as thin as possible, taking 3nm-6nm as an example, and the normal power-on of the organic functional layer 7 at the pixel opening 21 can be ensured;
(4) Taking out the structure obtained in the step (3) from the evaporation chamber, transferring to a nitrogen box, coating a layer of sacrificial layer material with the thickness of 0.5-1.5 mu m on the substrate 1 with the first cathode film layer 30 formed by adopting a gluing process, and then forming a sacrificial layer 10 by adopting a pre-baking process (the post-baking temperature is less than or equal to 90 ℃), as shown in fig. 6B;
(5) Coating a layer of negative photoresist material with the thickness of 1.5-2.5 mu m on the side, away from the substrate 1, of the sacrificial layer 10 by adopting a gluing process on the basis of the step (4), and then forming a photoresist layer 20 by adopting a pre-baking process (the post-baking temperature is less than or equal to 90 ℃), as shown in fig. 6C;
(6) On the basis of step (5), exposing the photoresist layer 20, wherein the exposed area comprises the pixel opening 21 and the transmission region 02, then developing the photoresist layer 20, and since the photoresist is negative, the exposed photoresist layer 20 is left on the substrate after development to remove the photoresist of the connection region 01, as shown in fig. 6D;
(7) On the basis of step (5), developing the sacrificial layer 10, wherein the sacrificial layer 10 is transversely retracted during the development process, and a T-shaped stripping column formed by the photoresist layer 20 (the part remaining after development) and the sacrificial layer 10 (the part remaining after development) is formed at the pixel opening 21 and in the transmission region 02, as shown in FIG. 6E;
(8) Placing the structure obtained in the step (7) in an evaporation chamber, evaporating a second cathode film layer 40 on the substrate 1 with the T-shaped stripping column formed thereon, and breaking the second cathode film layer 40 at the T-shaped stripping column, as shown in FIG. 6F; the thickness of the second cathode film layer 40 can be 30nm-60nm to reduce the resistance of the cathode in the connection region 02;
(9) Taking out the structure obtained in step (8) from the evaporation chamber, transferring to a nitrogen tank, placing the structure obtained in step (8) in a stripping liquid, dissolving the sacrificial layer 10 in the "T" shaped stripping column in the stripping liquid, and stripping from the substrate base plate 1, and simultaneously, stripping the cathode material on the "T" shaped stripping column from the substrate base plate 1 together, as shown in FIG. 6G, so that the pixel opening 21 and the cathode material of the permeation region 02 are stripped to form a third cathode part 33 at the pixel 21, a first cathode part 31 at the connection region 01, and a second cathode part 32 at the permeation region 02; wherein the first cathode portion 31, the second cathode portion 32 and the third cathode portion 33 constitute a cathode as shown in fig. 2.
The detailed process of fabricating the display substrate shown in fig. 3 is as follows:
first, (1) the structure shown in fig. 5I is obtained by using the same steps as those of steps (1) to (8) in manufacturing the display substrate shown in fig. 1;
next, (2) a sacrificial layer material with a thickness of 0.5 μm to 1.5 μm is coated on the substrate base plate 1 from which the first "T" type lift-off column (the "T" type lift-off column in fig. 5H) is peeled off on the basis of fig. 5I by a glue coating process, and then a second sacrificial layer 50 is formed by a pre-baking process (post-baking temperature is less than or equal to 90 ℃), as shown in fig. 7A;
(3) Coating a layer of negative photoresist material with the thickness of 1.5-2.5 mu m on the side, away from the substrate 1, of the second sacrificial layer 50 by adopting a gluing process on the basis of the step (2), and then forming a second photoresist layer 60 by adopting a pre-baking process (the post-baking temperature is less than or equal to 90 ℃), as shown in fig. 7B;
(4) Exposing the second photoresist layer 60 on the basis of step (3), wherein the exposure area comprises a transmission area 02, and then performing image development on the second photoresist layer 60 to remove the second photoresist at the connection area 01 and the pixel opening 21, as shown in fig. 7C;
(5) Developing the second sacrificial layer 50 on the basis of the step (4), wherein the second sacrificial layer 50 is transversely retracted during the development process, and a second T-shaped stripping column formed by the second photoresist layer 60 (the residual part after development) and the second sacrificial layer 50 (the residual part after development) is formed in the transmission region 02, as shown in FIG. 7D;
(6) Placing the structure obtained in the step (5) in an evaporation chamber, evaporating a second cathode film layer 40 on the substrate 1 formed with the second T-shaped stripping column, wherein the second cathode film layer 40 is broken at the second T-shaped stripping column, as shown in FIG. 7E; wherein, the thickness of the second cathode film layer 40 may be 3nm-6nm;
(7) Taking out the structure obtained in step (6) from the evaporation chamber, transferring to a nitrogen tank, placing the structure obtained in step (6) in a stripping liquid, dissolving the second sacrificial layer 50 in the second "T" type stripping column in the stripping liquid, and stripping from the substrate base plate 1, and simultaneously, stripping the cathode material on the second "T" type stripping column from the substrate base plate 1 together, as shown in fig. 7F, so that the cathode material of the transmission region 02 is stripped to form a third cathode portion 33 at the pixel opening 21, and forming a first cathode portion 31 at the connection region 01; the first cathode portion 31 and the third cathode portion 33 constitute a cathode 3 as shown in fig. 3.
In practical implementation, after the display substrate of fig. 1-3 provided by the present invention is manufactured, a light extraction layer and a subsequent encapsulation film layer are also manufactured, which will not be described in detail herein.
It should be noted that, in the above manufacturing method provided by the embodiment of the present invention, the manufacturing process for manufacturing each film layer may include only a photolithography process, or may include a photolithography process and an etching step, and may also include other processes for forming a predetermined pattern, such as printing, ink-jet, and the like; the photolithography process refers to a process of forming a pattern using photoresist, a mask plate, an exposure machine, etc., including processes of film formation, exposure, development, etc. In particular implementations, the corresponding patterning process may be selected in accordance with the structures formed in the present invention.
Based on the same inventive concept, the embodiment of the invention also provides a display panel, which comprises the display substrate provided by the embodiment of the invention. Other essential components of the display panel are those of ordinary skill in the art, and will not be described in detail herein, nor should they be construed as limiting the invention. The principle of the display panel for solving the problems is similar to that of the display substrate, so that the implementation of the display panel can be referred to the implementation of the display substrate, and the repetition is omitted herein.
Based on the same inventive concept, the embodiment of the invention also provides a display device, which comprises the display panel provided by the embodiment of the invention. The principle of the display device for solving the problems is similar to that of the display substrate, so that the implementation of the display device can be referred to the implementation of the display substrate, and the repetition is omitted herein.
In a specific implementation, the display device provided in the embodiment of the present invention may be a full-screen mobile phone as shown in fig. 8. Of course, the display device may be: tablet computers, televisions, displays, notebook computers, digital photo frames, navigator and any other products or components with display functions. Other essential components of the display device will be understood by those skilled in the art, and are not described herein in detail, nor should they be considered as limiting the invention.
According to the display substrate, the manufacturing method thereof, the display panel and the display device, the thickness of the second cathode part positioned in the transmission area in the cathode is set to be smaller than the thickness of the first cathode part positioned in the connection area in the cathode, compared with the scheme that the thicknesses of the cathodes at all positions in the related art are the same, the thickness of the second cathode part positioned in the transmission area in the cathode can be made to be thinner than the thickness of the cathode at the position of the transmission area in the related art, and the thickness of the first cathode part positioned in the connection area in the cathode can be made to be thicker than the thickness of the cathode at the position of the connection area in the related art, so that the scheme of the invention does not increase the cathode resistance in the whole, can improve the transmittance of the transmission area, and can improve the shooting performance under the OLED screen.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (11)
1. A display substrate, comprising:
a substrate including a plurality of sub-pixels;
a pixel defining layer on the substrate, the pixel defining layer including a plurality of pixel openings; wherein one of the subpixels comprises one of the pixel openings;
a cathode which is positioned on one side of the pixel defining layer, which is away from the substrate base plate; the orthographic projection of the cathode on the substrate covers the orthographic projection of the pixel opening on the substrate, and the orthographic projection of the cathode on the substrate overlaps the orthographic projection of the pixel defining layer on the substrate;
wherein the pixel defining layer has a connection region and a transmission region, and a portion of the cathode overlapping the pixel defining layer includes a first cathode portion and a second cathode portion; the first cathode part is positioned in the connecting area and has a first thickness; the second cathode part is positioned in the transmission area and has a second thickness; the second thickness is smaller than the first thickness, the portion of the cathode covering the pixel opening is a third cathode portion, the third cathode portion has a third thickness, and the third thickness is smaller than the first thickness.
2. The display substrate of claim 1, wherein the second thickness is not greater than the third thickness.
3. The display substrate of claim 1, wherein the connection region is located between the pixel opening and the transmission region or the transmission region is located between the pixel opening and the connection region.
4. The display substrate of claim 1, wherein regions between partially adjacent pixel openings are all the transmissive regions, and regions between partially adjacent pixel openings are all the connection regions.
5. The display substrate of claim 1, wherein the first thickness is 30nm-60nm and the third thickness is 3nm-6nm.
6. A display panel comprising a display substrate according to any one of claims 1-5.
7. A display device comprising the display panel according to claim 6.
8. A method for manufacturing a display substrate, comprising:
forming a pixel defining layer on a substrate having a plurality of sub-pixels; wherein the pixel defining layer includes a plurality of pixel openings, one of the sub-pixels including one of the pixel openings;
forming a cathode on one side of the pixel defining layer away from the substrate base plate; wherein the orthographic projection of the cathode on the substrate covers the orthographic projection of the pixel opening on the substrate, and the orthographic projection of the cathode on the substrate overlaps the orthographic projection of the pixel defining layer on the substrate, wherein the pixel defining layer has a connection region and a transmission region, and a portion of the cathode overlapping the pixel defining layer includes a first cathode portion and a second cathode portion; the first cathode part is positioned in the connecting area and has a first thickness; the second cathode part is positioned in the transmission area and has a second thickness; the second thickness is less than the first thickness; the portion of the cathode covering the pixel opening is a third cathode portion having a third thickness that is less than the first thickness.
9. The method of claim 8, wherein forming a cathode on a side of the pixel defining layer facing away from the substrate, specifically comprises:
forming a sacrificial layer on one side of the pixel defining layer away from the substrate base plate;
forming a photoresist layer on one side of the sacrificial layer, which is away from the substrate;
exposing and developing the photoresist layer to remove the photoresist in the connecting area;
developing the sacrificial layer, and forming a T-shaped stripping column formed by the photoresist layer and the sacrificial layer at the pixel opening and in the transmission region;
evaporating a first cathode film layer on a substrate base plate with the T-shaped stripping column, wherein the first cathode film layer is broken at the T-shaped stripping column; wherein the thickness of the first cathode film layer is 30nm-60nm;
stripping the "T" shaped stripper column;
evaporating a second cathode film layer on the substrate with the stripped T-shaped stripping column, wherein the thickness of the second cathode film layer is 3-6 nm so as to form a third cathode part at the pixel opening, form a first cathode part at the connecting region and form a second cathode part at the transmitting region; wherein the first cathode portion, the second cathode portion, and the third cathode portion constitute the cathode.
10. The method of claim 8, wherein forming a cathode on a side of the pixel defining layer facing away from the substrate, specifically comprises:
evaporating a first cathode film layer on one side of the pixel limiting layer, which is away from the substrate; the thickness of the first cathode film layer is 3nm-6nm;
forming a sacrificial layer on the substrate base plate with the first cathode film layer formed thereon;
forming a photoresist layer on one side of the sacrificial layer, which is away from the substrate;
exposing and developing the photoresist layer to remove the photoresist in the connecting area;
developing the sacrificial layer, and forming a T-shaped stripping column formed by the photoresist layer and the sacrificial layer at the pixel opening and in the transmission region;
evaporating a second cathode film layer on the substrate base plate with the T-shaped stripping column, wherein the second cathode film layer is broken at the T-shaped stripping column; wherein the thickness of the second cathode film layer is 30nm-60nm;
stripping the T-shaped stripping column to form a third cathode part at the pixel opening, a first cathode part at the connection region, and a second cathode part at the transmission region; wherein the first cathode portion, the second cathode portion, and the third cathode portion constitute the cathode.
11. The method of claim 8, wherein forming a cathode on a side of the pixel defining layer facing away from the substrate, specifically comprises:
forming a first sacrificial layer on one side of the pixel defining layer away from the substrate base plate;
forming a first photoresist layer on one side of the first sacrificial layer, which is away from the substrate;
exposing and developing the first photoresist layer to remove the first photoresist in the connecting area;
developing the first sacrificial layer, and forming a first T-shaped stripping column formed by the first photoresist layer and the first sacrificial layer at the pixel opening and in the transmission region;
evaporating a first cathode film layer on a substrate base plate with the first T-shaped stripping column formed, wherein the first cathode film layer is disconnected at the first T-shaped stripping column; wherein the thickness of the first cathode film layer is 30nm-60nm;
stripping the first "T" shaped stripper column;
forming a second sacrificial layer on the substrate base plate from which the first T-shaped stripping column is stripped;
forming a second photoresist layer on one side of the second sacrificial layer away from the substrate base plate;
exposing and developing the second photoresist layer to remove the second photoresist at the connection region and the pixel opening;
developing the second sacrificial layer, and forming a second T-shaped stripping column formed by the second photoresist layer and the second sacrificial layer in the transmission region;
evaporating a second cathode film layer on the substrate base plate with the second T-shaped stripping column, wherein the second cathode film layer is disconnected at the second T-shaped stripping column; wherein the thickness of the second cathode film layer is 3nm-6nm;
stripping the second T-shaped stripping column to form a third cathode part at the pixel opening and a first cathode part at the connection region; the first cathode portion and the third cathode portion constitute the cathode.
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