WO2020191832A1

WO2020191832A1 - Liquid crystal display device and method for manufacturing same

Info

Publication number: WO2020191832A1
Application number: PCT/CN2019/083075
Authority: WO
Inventors: 韦宏权; 陈兴武
Original assignee: 深圳市华星光电技术有限公司
Priority date: 2019-03-26
Filing date: 2019-04-17
Publication date: 2020-10-01
Also published as: CN109917587A; CN109917587B

Abstract

A liquid crystal display device and a method for manufacturing same. The liquid crystal display device comprises a backlight module (1), a quantum dot layer (3) on the light emitting side of the backlight module (1), a photoluminescence conversion layer (4) provided on the side of the quantum dot layer (3) distant from the backlight module (1), a liquid crystal display panel (2) provided on the side of the photoluminescence conversion layer (4) distant from the quantum dot layer (3), and a polarizer (5) provided on the side of the liquid crystal display panel (2) distant from the photoluminescence conversion layer (4). The backlight module (1) is used for emitting backlight to excite the quantum dot layer (3) to emit light. The photoluminescence conversion layer (4) is used for converting the backlight passing through the quantum dot layer (3) into polarized light having a wavelength of 460 nm or greater. The conversion of low-wavelength backlight into polarized light having a wavelength of 460 nm or greater by the photoluminescence conversion layer (4) can save a lower polarizer commonly used at present, and improve the backlight utilization rate and the transmissivity of a display device.

Description

Liquid crystal display device and manufacturing method thereof

Technical field

The present invention relates to the field of display technology, in particular to a liquid crystal display device and a manufacturing method thereof.

Background technique

Thin Film Transistor-Liquid Crystal Display (TFT-LCD) has many advantages such as thin body, power saving, and no radiation, and has been widely used. Such as: LCD TV, mobile phone, personal digital assistant (PDA), digital camera, computer screen or notebook computer screen, etc., occupy a dominant position in the field of flat panel display. Most of the liquid crystal displays on the current market are backlit liquid crystal displays, which include liquid crystal panels and backlight modules (Backlight Module). The working principle of the liquid crystal panel is to apply a driving voltage on the Thin Film Transistor Array Substrate (TFT Array Substrate) and the Color Filter (CF) substrate to control the rotation direction of the liquid crystal molecules between the two substrates. The light from the backlight module is refracted to produce a picture.

Since the liquid crystal display panel itself does not emit light and needs to use the light source provided by the backlight module to display images normally, the backlight module has become one of the key components of the liquid crystal display. The existing backlight module has a low color gamut level. In order to further improve the color gamut level, Quantum Dot backlight module technology has emerged. Quantum dot luminescent materials comply with the quantum size effect, and their properties change with the size of the quantum dots. When stimulated by light or electricity, quantum dots emit colored light. The color of the light is related to its nature, so the light emitted by it can be controlled by changing its size. Quantum dot luminescent materials have the advantages of concentrated emission spectrum and high color purity. The use of quantum dot luminescent materials in the field of display technology can greatly increase the color gamut of traditional displays and enhance the color reproduction capability of the display. The quantum dot backlight module takes advantage of this feature of quantum dots, uses the backlight to irradiate the quantum dot layer to excite different colors of color light, and the same part of the color light that passes through the quantum dots is mixed to obtain white light, thereby improving the overall backlight module Luminous effect.

As shown in FIG. 1, an existing liquid crystal display device using a quantum dot backlight module includes a backlight module 10, a quantum dot layer 20, a cut-off layer 30, a lower polarizer 40, a liquid crystal display panel 50, and The upper polarizer 60 requires high-energy backlight lasers, such as ultraviolet light and blue light, to be excited by the quantum dot layer 20. These short-wavelength lights are more harmful to human eyes. In order to prevent low-wavelength light from penetrating into human eyes, A cut-off layer 30 is added to cut off low-wavelength light such as ultraviolet light and blue light to prevent leakage. However, the cut-off layer 30 also reduces the light utilization rate of the backlight and affects the transmittance of the display.

Summary of the invention

The object of the present invention is to provide a liquid crystal display device that can improve the utilization rate of the backlight and the transmittance of the display device.

The object of the present invention is also to provide a method for manufacturing a liquid crystal display device, which can improve the utilization rate of the backlight and the transmittance of the display device.

In order to achieve the above objective, the present invention provides a liquid crystal display device, which includes a backlight module, a quantum dot layer arranged on the light-emitting side of the backlight module, and a light-induced A luminescence conversion layer, a liquid crystal display panel disposed on the side of the photoluminescence conversion layer away from the quantum dot layer, and a polarizer disposed on the side of the liquid crystal display panel away from the photoluminescence conversion layer;

The backlight module is used to emit a backlight to excite the quantum dot layer to emit light;

The photoluminescence conversion layer is used to convert the backlight passing through the quantum dot layer into polarized light with a wavelength greater than 460 nm.

The backlight emitted by the backlight module is blue or ultraviolet light.

The material of the photoluminescence conversion layer includes a first compound obtained by introducing a photoluminescence group into the side chain of a dichroic dye.

The dichroic dye is an azo compound, and the photoluminescent group is one or a combination of polyfluorene, polythiophene, polypyrrole or polyaniline.

The present invention provides a method for manufacturing a liquid crystal display device, which includes the following steps:

Step S1: Provide a backlight module, and form a quantum dot layer on the light exit side of the backlight module, and the backlight module can emit a backlight to stimulate the quantum dot layer to emit light;

Step S2, forming a photoluminescence conversion layer on the side of the quantum dot layer away from the backlight module, the photoluminescence conversion layer being able to convert the backlight passing through the quantum dot layer into polarized light with a wavelength greater than 460nm;

Step S3, disposing a liquid crystal display panel on the side of the photoluminescence conversion layer away from the quantum dot layer, and disposing a polarizer on the side of the liquid crystal display panel away from the photoluminescence conversion layer.

The backlight emitted by the backlight module is blue or ultraviolet light.

The step S2 specifically includes:

Step S21: Provide a solution, the solution comprising a first compound, a small molecule polymerizable monomer, a solvent and additives, the first compound is obtained by introducing a photoluminescent group into the side chain of the dichroic dye;

Step S22, coating the solution and aligning it to form a photoluminescence conversion layer.

The step S22 includes:

An alignment layer is formed first, the solution is coated on the alignment layer, and the solution is heated to cure the solution into a film to form the photoluminescence conversion layer.

In the step 21, the dichroic dye is an azo compound;

The step S22 includes: coating the solution, heating the solution to cure the solution into a film, and irradiating the film layer cured by the solution with linearly polarized ultraviolet light in the same direction to align the film layer to form the Photoluminescence conversion layer.

In the step 21, the dichroic dye is an azo compound, and the photoluminescent group is one or a combination of polyfluorene, polythiophene, polypyrrole or polyaniline.

The beneficial effects of the present invention: the present invention provides a liquid crystal display device, which includes a backlight module, a quantum dot layer arranged on the light-emitting side of the backlight module, and a light arranged on the side of the quantum dot layer away from the backlight module. An electroluminescence conversion layer, a liquid crystal display panel disposed on the side of the photoluminescence conversion layer away from the quantum dot layer, and a polarizer disposed on the side of the liquid crystal display panel away from the photoluminescence conversion layer; The backlight module is used to emit backlight to excite the quantum dot layer to emit light; the photoluminescence conversion layer is used to convert the backlight passing through the quantum dot layer into polarized light with a wavelength greater than 460nm, and the photoluminescence conversion layer The low-wavelength backlight is converted into polarized light with a wavelength greater than 460nm, which can save the existing commonly used lower polarizer and improve the utilization rate of the backlight and the transmittance of the display device. The present invention also provides a method for manufacturing a liquid crystal display device, which can omit the lower polarizer and improve the utilization rate of the backlight and the transmittance of the display device.

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,

FIG. 1 is a schematic diagram of a conventional liquid crystal display device;

2 is a schematic diagram of the liquid crystal display device of the present invention;

3 is a schematic diagram of step S2 of the first embodiment of the manufacturing method of the liquid crystal display device of the present invention;

4 is a schematic diagram of step S2 of the second embodiment of the manufacturing method of the liquid crystal display device of the present invention;

FIG. 5 is a flowchart of a method of manufacturing the liquid crystal display device of the present invention.

detailed description

In order to further illustrate 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. 2, the present invention provides a liquid crystal display device including a backlight module 1, a quantum dot layer 3 arranged on the light-emitting side of the backlight module 1, and a quantum dot layer 3 arranged on the quantum dot layer 3 away from the backlight module 1 The photoluminescence conversion layer 4 on the side, the liquid crystal display panel 2 disposed on the side of the photoluminescence conversion layer 4 away from the quantum dot layer 3, and the liquid crystal display panel 2 disposed away from the photoluminescence conversion layer Polarizer 5 on one side of 4;

The backlight module 1 is used to emit a backlight to excite the quantum dot layer 3 to emit light;

The photoluminescence conversion layer 4 is used for converting light incident on the photoluminescence conversion layer 4 into polarized light with a wavelength greater than 460 nm.

Specifically, the backlight emitted by the backlight module 1 is blue light or ultraviolet light.

Specifically, the material of the photoluminescence conversion layer 4 includes a first compound obtained by introducing a photoluminescence group into the side chain of a dichroic dye, and the structure of the first compound is as follows:

Wherein, A is a dichroic dye, B is a photoluminescent group, preferably, the dichroic dye is an azo compound, and the photoluminescent group can be selected from polyfluorene, polythiophene, polypyrrole and It can be selected from polyaniline, and the photoluminescent group introduced can be one or a combination of the above-mentioned polyfluorene, polythiophene, polypyrrole, and polyaniline.

Preferably, the photoluminescent group can be excited by light from 200 nm to 460 nm to emit light with a wavelength greater than 460 nm.

It should be noted that the dichroic dye in the photoluminescence conversion layer 4 of the present invention has been aligned to have a uniform alignment direction, and the photoluminescent groups introduced into the side chain of the dichroic dye also have a uniform alignment direction. Therefore, the light emitted by the photoluminescence group is excited to have the same exit direction, that is, the light emitted by the photoluminescence conversion layer 4 is polarized light, so that the photoluminescence conversion layer 4 can simultaneously replace the existing technology. The cut-off layer and the lower polarizer can not only prevent short-wavelength light from being emitted to human eyes, but also realize the conversion of polarized light, which can effectively improve the utilization rate of the backlight and the transmittance of the display device.

Further, through alignment, the photoluminescence conversion layer 4 has a polarization axis perpendicular to the polarization axis of the polarizer 5.

Referring to FIG. 5, the present invention also provides a manufacturing method of a liquid crystal display device, including the following steps:

Step S1, a backlight module 1 is provided, and a quantum dot layer 3 is formed on the light exit side of the backlight module 1, and the backlight module 1 can emit a backlight to excite the quantum dot layer 3 to emit light.

Step S2. A photoluminescence conversion layer 4 is formed on the side of the quantum dot layer 3 away from the backlight module 1. The photoluminescence conversion layer 4 can convert the backlight passing through the quantum dot layer 3 to a wavelength greater than 460nm Polarized light.

Specifically, the step S2 specifically includes:

Step S21: Provide a solution, the solution including a first compound, a small molecule polymerizable monomer, a solvent and additives, and the first compound is obtained by introducing a photoluminescent group into the side chain of the dichroic dye.

The structure of the first compound is as follows:

Further, in the solution, the mass ratio of the first compound is 1% to 30%, the mass ratio of the small molecule polymerizable monomer is 10% to 30%, and the mass ratio of the solvent is 50% to 80%. , The mass ratio of additives is 0.1% to 0.5%.

Preferably, the small-molecule polymerizable monomer is a small-molecule polymerizable monomer containing polymerizable chain groups such as double bonds, acrylic ester groups, and methacrylic ester groups, and the solvent is acetone, toluene, propylene glycol, and dichloromethane. One or more of methane and chloroform, and the additives include photoinitiators and dispersants.

Step S22, coating the solution and aligning it to form the photoluminescence conversion layer 4.

Specifically, the alignment method in step S22 includes two methods: physical alignment and optical alignment.

Further, as shown in FIG. 3, in the physical alignment method, the step S22 includes:

Firstly, an alignment layer 101 is formed, and the solution is coated on the alignment layer 101, and heated to cure the solution into a film to form the photoluminescence conversion layer 4.

Specifically, the material of the alignment layer 101 can be selected from polyimide (PI), the alignment layer 101 is aligned to have a uniform alignment pattern, the solution is coated on the alignment layer 101 and heated so that The solution is cured into a film, and the film layer generates a corresponding pattern along with the alignment pattern on the alignment layer 101, thereby completing the alignment of the film layer, and forming the photoluminescence conversion layer 4.

Specifically, the solvent is volatilized by heating and the small-molecule polymerizable monomer is promoted to polymerize, so that the solution is cured into a film.

Further, in the step 21, when the dichroic dye is an azo compound, optical alignment can also be used.

As shown in FIG. 4, during optical alignment, the step S22 includes: coating the solution on the carrier 100, heating to cure the solution into a film, and irradiating the solution with linearly polarized ultraviolet light in the same direction to cure The obtained film layer utilizes azo molecules to respond to ultraviolet polarized light, undergo isomerization, complete the alignment of the film layer, and form the photoluminescence conversion layer 4.

In summary, the present invention provides a liquid crystal display device, which includes a backlight module, a quantum dot layer arranged on the light-emitting side of the backlight module, and a light-induced light emitting diode layer arranged on the side of the quantum dot layer away from the backlight module. A luminescence conversion layer, a liquid crystal display panel disposed on the side of the photoluminescence conversion layer away from the quantum dot layer, and a polarizer disposed on the side of the liquid crystal display panel away from the photoluminescence conversion layer; the backlight The module is used to emit a backlight to excite the quantum dot layer to emit light; the photoluminescence conversion layer is used to convert the backlight passing through the quantum dot layer into polarized light with a wavelength greater than 460nm, and the photoluminescence conversion layer reduces The wavelength of the backlight is converted into polarized light with a wavelength greater than 460nm, which can save the conventional lower polarizer and improve the utilization rate of the backlight and the transmittance of the display device. The present invention also provides a method for manufacturing a liquid crystal display device, which can omit the lower polarizer and improve the utilization rate of the backlight and the transmittance of the display device.

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 liquid crystal display device, comprising a backlight module, a quantum dot layer arranged on the light emitting side of the backlight module, a photoluminescence conversion layer arranged on the side of the quantum dot layer away from the backlight module, and A liquid crystal display panel on a side of the electroluminescence conversion layer away from the quantum dot layer and a polarizer provided on a side of the liquid crystal display panel away from the photoluminescence conversion layer;

The backlight module is used to emit a backlight to excite the quantum dot layer to emit light;

The photoluminescence conversion layer is used to convert light incident on the photoluminescence conversion layer into polarized light with a wavelength greater than 460nm.
8. The liquid crystal display device of claim 1, wherein the backlight emitted by the backlight module is blue light or ultraviolet light.
8. The liquid crystal display device of claim 1, wherein the material of the photoluminescence conversion layer includes a first compound obtained by introducing a photoluminescence group into a side chain of a dichroic dye.
The liquid crystal display device of claim 3, wherein the dichroic dye is an azo compound, and the photoluminescent group is one or more of polyfluorene, polythiophene, polypyrrole or polyaniline Kind of combination.
A method for manufacturing a liquid crystal display device includes the following steps:

Step S1: Provide a backlight module, and form a quantum dot layer on the light exit side of the backlight module, and the backlight module can emit a backlight to stimulate the quantum dot layer to emit light;

Step S2. A photoluminescence conversion layer is formed on the side of the quantum dot layer away from the backlight module. The photoluminescence conversion layer can convert light incident on the photoluminescence conversion layer into polarized light with a wavelength greater than 460nm. ；

Step S3, disposing a liquid crystal display panel on the side of the photoluminescence conversion layer away from the quantum dot layer, and disposing a polarizer on the side of the liquid crystal display panel away from the photoluminescence conversion layer.
7. The method for manufacturing a liquid crystal display device according to claim 5, wherein the backlight emitted by the backlight module is blue light or ultraviolet light.
7. The method of manufacturing a liquid crystal display device according to claim 5, wherein said step S2 specifically comprises:

Step S21: Provide a solution, the solution comprising a first compound, a small molecule polymerizable monomer, a solvent and additives, the first compound is obtained by introducing a photoluminescent group into the side chain of the dichroic dye;

Step S22, coating the solution and aligning it to form a photoluminescence conversion layer.
8. The method of manufacturing a liquid crystal display device according to claim 7, wherein said step S22 comprises:

First, an alignment layer is formed, the solution is coated on the alignment layer, and the solution is heated to cure the solution into a film to form the photoluminescence conversion layer.
8. The method for manufacturing a liquid crystal display device according to claim 7, wherein in the step 21, the dichroic dye is an azo compound;

The step S22 includes: coating the solution, heating the solution to cure the solution into a film, and irradiating the film layer cured by the solution with linearly polarized ultraviolet light in the same direction to align the film layer to form the Photoluminescence conversion layer.
7. The method for manufacturing a liquid crystal display device according to claim 7, wherein in the step 21, the dichroic dye is an azo compound, and the photoluminescent group is polyfluorene, polythiophene, polypyrrole Or a combination of one or more of polyaniline.