WO2020186542A1

WO2020186542A1 - Manufacturing method of alignment film, and alignment film

Info

Publication number: WO2020186542A1
Application number: PCT/CN2019/079662
Authority: WO
Inventors: 赵永超
Original assignee: 深圳市华星光电半导体显示技术有限公司
Priority date: 2019-03-18
Filing date: 2019-03-26
Publication date: 2020-09-24
Also published as: CN109765730B; CN109765730A

Abstract

Provided are a manufacturing method of an alignment film, and an alignment film. The manufacturing method of an alignment film comprises: providing a substrate having a first region, a second region and a third region sequentially arranged in an outward direction; and when jetting an alignment film solution on the substrate, configuring the volume of a single drop of the alignment film solution jetted on the first region to be less than the volume of a single drop of the alignment film solution jetted on the second region, and configuring the volume of a single drop of the alignment film solution jetted on the first region to be greater than the volume of a single drop of the alignment film solution jetted on the third region, thereby forming, on the substrate, an alignment film having a smaller halo region and high thickness uniformity. The invention can solve the problem of nonuniform brightness at the periphery.

Description

Manufacturing method of alignment film and alignment film

Technical field

The present invention relates to the field of display technology, in particular to a manufacturing method of an alignment film and an alignment film.

Background technique

Liquid Crystal Display (LCD) has many advantages such as thin body, power saving, and no radiation, and has been widely used. However, as we all know, liquid crystal displays are passive light-emitting devices, and the liquid crystal material itself does not emit light. Therefore, most of the existing liquid crystal displays on the market are backlight liquid crystal displays, which include liquid crystal display panels and backlight modules (backlight module).

The working principle of the liquid crystal display panel is to place liquid crystal molecules between two parallel glass substrates. By applying a driving voltage on the two glass substrates, the liquid crystal molecules are controlled to change direction, and the light from the backlight module is refracted to produce images. Usually the LCD panel is made of color filter film (Color Filter, CF) substrate, thin film transistor (Thin Film Transistor, TFT) array substrate, liquid crystal (LC) sandwiched between the color filter film substrate and the thin film transistor array substrate, and a sealant frame (Sealant).

At present, in the middle-stage cell forming process of liquid crystal display panels, an alignment film (PI, namely polyimide) is usually first fabricated on a thin film transistor (TFT) array substrate and a color filter film (CF) substrate, and then Coat the sealing sealant on the thin film transistor array substrate and drop the liquid crystal, then bond the thin film transistor array substrate and the color filter film substrate in a vacuum state, and finally cure the seal sealant by ultraviolet irradiation to complete the thin film transistor array substrate And color filter film substrate packaging.

There are mainly two ways to make alignment films. One is to transfer the alignment film using a printing plate, the other is to make the alignment film by inkjet printing, and the alignment film is made by inkjet printing. No printing plate is required, the graphics are directly input into the computer, and the alignment film solution is sprayed onto the substrate through a set of nozzles. The equipment has a simple structure and greatly saves costs. 1, when the alignment film is made by inkjet printing, when the alignment film solution is inkjet printed to the area 110 of the substrate 100 where the alignment film is to be formed, the alignment film at different positions in the area 110 where the alignment film is to be formed The single drop volume of the solution is the same (generally 85ng). Please refer to Figure 2. After the alignment film solution is inkjet printed on the substrate 100, under the action of surface tension, the edge of the alignment film 200 will eventually form a thickness A uniform halo region 210, the halo region 220 includes a first part A and a second part B arranged in sequence along the edge away from the alignment film 200, wherein the upper surface of the first part A protrudes away from the substrate 100, the first part The thickness of the region A with the largest thickness is greater than the thickness of the alignment film 200 located outside the halo region 220, and the thickness of the second portion B is smaller than the thickness of the alignment film 200 located outside the halo region 220. Due to the existence of the halo zone, the topography of the alignment film surface is uneven, and the distribution of the liquid crystal on the surface of the alignment film is chaotic. The pretilt angle of the liquid crystal corresponding to the halo zone is different from other regions. At the same time, the different thickness of the alignment film will cause the alignment film There is a difference in the penetration rate of the halo area, and both factors will cause the brightness of the halo area to be inconsistent with other areas, resulting in uneven brightness (mura).

technical problem

The purpose of the present invention is to provide a method for manufacturing an alignment film, which can reduce the size of the halo region of the alignment film, improve the uniformity of the thickness of the alignment film, and help eliminate uneven brightness around the periphery.

Another object of the present invention is to provide an alignment film whose halo area has a small size and a high thickness uniformity, which helps to eliminate the unevenness of peripheral brightness.

Technical solutions

In order to achieve the above objective, the present invention first provides a method for manufacturing an alignment film, which includes the following steps:

Step S1, providing a substrate;

The substrate includes a first area, a second area located outside the first area, and a third area located outside the second area;

Step S2. Inkjet printing the alignment film solution onto the substrate, and the single drop volume of the alignment film solution inkjet printing to the first area is smaller than the single drop volume inkjet printing the alignment film solution to the second area, and inkjet printing to the first area The amount of a single drop of the printing alignment film solution is greater than the amount of a single drop of the inkjet printing alignment film solution to the third area, thereby forming an alignment film on the substrate.

The alignment film includes a central area and a halo area located outside the central area. The halo area includes a first part and a second part arranged in a direction away from the central area; the thickness of the first part is less than the thickness of the central area, so The upper surface of the first part is recessed in the direction close to the substrate; the upper surface of the second part protrudes in the direction away from the substrate; the second part is located on the third area of the substrate, and the first part is located on the second area of the substrate. Regionally, the vertical projection of the boundary between the halo area and the central area is located in the second area.

In the step S2, the alignment film solution is ink-jet printed to the first area, the second area, and the third area sequentially.

In the step S2, the single drop volume of the alignment film solution for inkjet printing to the first area is 45-85ng; the single drop volume of the alignment film solution for inkjet printing to the second area is 85-125ng; The amount of a single drop of the inkjet printing alignment film solution in the third area is 30-60ng.

In the step S2, the single drop volume of the alignment film solution for inkjet printing to the first area is 85ng; the single drop volume of the alignment film solution for inkjet printing to the second area is 124ng; The single drop volume of the inkjet printing alignment film solution is 60ng.

The distance between the first area and the third area away from the edge of the first area is 1-3 mm.

The distance between the second area and the third area away from the edge of the first area is 0.1-0.3 mm.

The substrate is a thin film transistor array substrate or a color filter substrate.

The alignment film solution is a polyimide solution.

The present invention also provides an alignment film, which is made by using the above-mentioned manufacturing method of the alignment film; the alignment film includes a central area and a halo area located outside the central area, and the halo area includes a central area away from the central area. The first part and the second part; the thickness of the first part is less than the thickness of the central area, the upper surface of the first part is recessed in the direction close to the substrate; the upper surface of the second part protrudes in the direction away from the substrate; The second part is located on the third area of the substrate, the first part is located on the second area of the substrate, and the vertical projection of the boundary between the halo area and the central area is located in the second area.

Beneficial effect

The beneficial effects of the present invention: The method for manufacturing the alignment film provided by the present invention provides a substrate with a first area, a second area, and a third area sequentially arranged from the inside to the outside. When inkjet printing the alignment film solution onto the substrate, The single drop volume of the alignment film solution for inkjet printing in one area is smaller than the single drop volume of the alignment film solution for inkjet printing to the second area, and the single drop volume of the alignment film solution for inkjet printing to the first area is greater than that for the third area The amount of a single drop of the alignment film solution can form an alignment film with a smaller halo area and a higher thickness uniformity on the substrate, which helps to eliminate uneven brightness around the periphery. The halo region of the alignment film of the present invention has a small size and a high thickness uniformity, which helps to eliminate the unevenness of peripheral brightness.

Description of the drawings

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and accompanying drawings of the present invention. However, the accompanying drawings are only provided for reference and illustration and are not used to limit the present invention.

In the attached picture,

1 and 2 are schematic diagrams of forming an alignment film by inkjet printing in the prior art;

3 is a flowchart of the manufacturing method of the alignment film of the present invention;

4 is a schematic diagram of step S1 of the manufacturing method of the alignment film of the present invention;

5 is a schematic diagram of step S2 of the manufacturing method of the alignment film of the present invention.

Embodiments of the invention

In order to further explain the technical means adopted by the present invention and its effects, the following describes in detail the preferred embodiments of the present invention and the accompanying drawings.

Referring to FIG. 3, the present invention provides a manufacturing method of an alignment film, which includes the following steps:

Step S1, please refer to FIG. 4 to provide a substrate 10.

The substrate 10 includes a first area 11, a second area 12 located outside the first area 11, and a third area 13 located outside the second area 12.

Specifically, the substrate 10 may be a thin film transistor array substrate or a color filter substrate, that is, the present invention can be used to make an alignment film on the side of a thin film transistor array substrate or can be used to make an alignment film on the side of a color filter substrate.

Step S2. Inkjet printing the alignment film solution onto the substrate 10, and the single drop volume of the alignment film solution inkjet printing on the first area 11 is smaller than the single drop volume of the alignment film solution inkjet printing on the second area 12, The amount of a single drop of the inkjet printing alignment film solution in the area 11 is greater than the amount of a single drop of the inkjet printing alignment film solution to the third area 13, so referring to FIG. 5, the alignment film 20 is formed on the substrate 10.

Specifically, referring to FIG. 5, the alignment film 20 includes a central area 21 and a halo area 22 located outside the central area 21. The halo area 22 includes a first portion 221 and a second portion arranged in a direction away from the central area 21. 222. The thickness of the first portion 221 is smaller than the thickness of the central region 21, the upper surface of the first portion 221 is recessed in a direction close to the substrate 10, and the upper surface of the second portion 222 protrudes in a direction away from the substrate 10, so The second portion 222 is located on the third area 13, the first portion 221 is located on the second area 12, and the vertical projection of the boundary between the halo area 22 and the central area 21 is located in the second area 12.

Specifically, in the step S2, the single drop volume of the alignment film solution for inkjet printing to the first area 11 is 45-85 ng, and the single drop volume of the alignment film solution for inkjet printing to the second area 12 is 85 ng. -125ng, the single drop volume of the alignment film solution for inkjet printing to the third area 13 is 30-60ng.

Preferably, in the step S2, the single drop of the alignment film solution for inkjet printing to the first area 11 is 85 ng, and the single drop of the alignment film solution for inkjet printing to the second area 12 is 124 ng. The single drop of the inkjet printing alignment film solution in the third area 13 is 60 ng.

Specifically, in the step S2, the alignment film solution is ink-jet printed to the first area 11, the second area 12, and the third area 13 in sequence.

Preferably, the distance between the edges of the first area 11 and the third area 13 away from the first area 11 is 1-3 mm. The distance between the second area 12 and the third area 13 away from the edge of the first area 11 is 0.1-0.3 mm.

Specifically, the alignment film solution is a polyimide solution.

It should be noted that, in the method for manufacturing the alignment film provided by the present invention, when the alignment film solution is inkjet printed on the substrate 10, the single drop volume of the alignment film solution inkjet printing to the first area 11 is controlled to be smaller than that of the second area. 12 Inkjet printing the single drop volume of the alignment film solution, and control the single drop volume of the inkjet printing alignment film solution to the first area 11 to be larger than the single drop volume of the inkjet printing alignment film solution to the third area 13 11 The single drop volume of the inkjet printing alignment film solution can be consistent with the uniform single drop volume set during the inkjet printing of the alignment film solution in the prior art, and the single drop of the inkjet printing alignment film solution to the first area is controlled. The amount is smaller than the amount of a single drop of the alignment film solution for inkjet printing to the second area 12, so that the amount of the alignment film solution in the second area 12 is greater than the amount of the alignment film solution in the first area 11, which can increase the halo in the prior art. The thickness of the thinner part of the film in the region makes the size of the halo region 22 of the alignment film 20 finally formed smaller than that of the prior art, and makes the amount of single drop of the alignment film solution inkjet printed to the first region 11 larger than that of the alignment film. The third area 13 inkjet prints the single drop of the alignment film solution, which can reduce the thickness of the second portion 222 in the halo area 22 so that the thickness of the area where the thickness of the second portion 222 is the largest is equal to the thickness of the alignment film 20 outside the halo area 22 Therefore, the thickness difference of the alignment film 20 is effectively reduced, and the uniformity of the thickness of the alignment film 20 is improved, thereby eliminating the uneven distribution of the pretilt angle caused by the uneven thickness of the alignment film 20. , And can eliminate the difference in transmittance caused by the uneven thickness of the alignment film 20, reduce the brightness difference through the above two points, thereby effectively improving the peripheral brightness unevenness of the liquid crystal display panel made by the alignment film, and improving the quality of the product .

Please refer to FIG. 5, based on the same inventive concept, the present invention also provides an alignment film manufactured by the above-mentioned manufacturing method of the alignment film. The alignment film 20 includes a central area 21 and a halo area 22 located outside the central area 21. The halo area 22 includes a first portion 221 and a second portion 222 arranged in order along a direction away from the central area 21. The thickness of the first portion 221 is smaller than the thickness of the central area 21, and the upper surface of the first portion 221 is closer to the substrate 10. The upper surface of the second portion 222 protrudes away from the substrate 10, the second portion 222 is located on the third area 13 of the substrate 10, and the first portion 221 is located on the second area 12 of the substrate The vertical projection of the boundary between the halo area 22 and the central area 21 is located in the second area 12.

It should be noted that the alignment film of the present invention is prepared by using the above-mentioned manufacturing method of the alignment film, by controlling the amount of a single drop of the alignment film solution for inkjet printing to the first area 11 when the alignment film solution is inkjet printed on the substrate 10 It is smaller than the single drop volume of the alignment film solution for inkjet printing to the second area 12, and the single drop volume of the alignment film solution for inkjet printing to the first area 11 is controlled to be greater than the single drop volume of the alignment film solution for inkjet printing to the third area 13 , The single drop volume of the inkjet printing alignment film solution to the first area 11 can be consistent with the uniform single drop volume set during the inkjet printing of the alignment film solution in the prior art, and the inkjet printing alignment to the first area 11 is controlled The amount of a single drop of the membrane solution is smaller than the amount of a single drop of the alignment membrane solution for inkjet printing to the second area 12, so that the amount of the alignment film solution in the second area 12 is greater than the amount of the alignment film solution in the first area 11, which can increase The thickness of the thinner part of the halo region in the prior art makes the size of the halo region 22 of the finally formed alignment film 20 smaller than that in the prior art, so that the inkjet printing of the alignment film solution to the first region 11 The single drop volume is larger than the single drop volume of the inkjet printing alignment film solution to the third area 13, which can reduce the thickness of the second portion 222 in the halo area 22 so that the thickness of the area with the largest thickness of the second portion 222 is aligned with the outside of the halo area 22 The thickness of the film 20 tends to be uniform, thereby effectively reducing the difference in film thickness of the alignment film 20 and improving the uniformity of the thickness of the alignment film 20, thereby eliminating the uneven distribution of liquid crystal caused by the uneven thickness of the alignment film 20 The pretilt angle distribution is not uniform, and the difference in transmittance caused by the uneven thickness of the alignment film 20 can be eliminated, and the brightness difference is reduced through the above two points, thereby effectively improving the peripheral brightness unevenness of the liquid crystal display panel made of the alignment film , Improve the quality of products.

In summary, the manufacturing method of the alignment film provided by the present invention provides a substrate with a first area, a second area, and a third area sequentially arranged from the inside to the outside. When inkjet printing the alignment film solution onto the substrate, the first area The single drop volume of the alignment film solution for area inkjet printing is smaller than the single drop volume of the alignment film solution for inkjet printing to the second area, and the single drop volume of the alignment film solution for inkjet printing to the first area is greater than that for the third area The amount of a single drop of the film solution can form an alignment film with a smaller halo zone size and a higher thickness uniformity on the substrate, which helps to eliminate the unevenness of the peripheral brightness. The halo region of the alignment film of the present invention has a small size and a high thickness uniformity, which helps to eliminate the unevenness of peripheral brightness.

As mentioned above, for those of ordinary skill in the art, various other corresponding changes and modifications can be made according to the technical solutions and technical ideas of the present invention, and all these changes and modifications shall fall within the protection scope of the claims of the present invention. .

Claims

A manufacturing method of an alignment film includes the following steps:

Step S1, providing a substrate;

The substrate includes a first area, a second area located outside the first area, and a third area located outside the second area;

Step S2. Inkjet printing the alignment film solution onto the substrate, and the single drop volume of the alignment film solution inkjet printing to the first area is smaller than the single drop volume inkjet printing the alignment film solution to the second area, and inkjet printing to the first area The amount of a single drop of the printing alignment film solution is greater than the amount of a single drop of the inkjet printing alignment film solution to the third area, thereby forming an alignment film on the substrate.
The method of manufacturing an alignment film according to claim 1, wherein the alignment film includes a central area and a halo area located outside the central area, and the halo area includes a first part and a second part arranged in a direction away from the central area. The thickness of the first part is less than the thickness of the central area, the upper surface of the first part is recessed toward the direction close to the substrate; the upper surface of the second part protrudes away from the substrate; the second part is located on the substrate On the third area of the substrate, the first part is located on the second area of the substrate, and the vertical projection of the boundary between the halo area and the central area is located in the second area.
8. The method for manufacturing an alignment film according to claim 1, wherein in step S2, the alignment film solution is ink-jet printed to the first area, the second area, and the third area sequentially.
The method for manufacturing an alignment film according to claim 1, wherein, in the step S2, the amount of a single drop of the alignment film solution for inkjet printing to the first area is 45-85ng; The single drop volume of the printing alignment film solution is 85-125ng; the single drop volume of the inkjet printing alignment film solution to the third area is 30-60ng.
4. The method for manufacturing an alignment film according to claim 4, wherein, in the step S2, the amount of a single drop of the inkjet printing alignment film solution to the first area is 85 ng; and the inkjet printing alignment to the second area The single drop of the membrane solution is 124ng; the single drop of the inkjet printing alignment membrane solution to the third area is 60ng.
8. The manufacturing method of the alignment film according to claim 1, wherein the distance between the edge of the first area and the third area away from the first area is 1-3 mm.
7. The manufacturing method of the alignment film according to claim 6, wherein the distance between the edge of the second area and the third area away from the first area is 0.1-0.3 mm.
8. The manufacturing method of the alignment film according to claim 1, wherein the substrate is a thin film transistor array substrate or a color filter substrate.
8. The method for manufacturing an alignment film according to claim 1, wherein the alignment film solution is a polyimide solution.
An alignment film, manufactured by the method for manufacturing an alignment film according to claim 1; the alignment film includes a central area and a halo area located outside the central area, and the halo area includes sequential arrangement along a direction away from the central area The first part and the second part; the thickness of the first part is smaller than the thickness of the central area, the upper surface of the first part is recessed toward the direction close to the substrate; the upper surface of the second part protrudes away from the substrate; The second portion is located on the third area of the substrate, the first portion is located on the second area of the substrate, and the vertical projection of the boundary between the halo area and the central area is located in the second area.

To