WO2022134309A1

WO2022134309A1 - Display device, manufacturing method therefor and use thereof

Info

Publication number: WO2022134309A1
Application number: PCT/CN2021/078999
Authority: WO
Inventors: 张志宽; 高丹鹏; 杨丽敏; 徐冰; 孙小卫
Original assignee: 深圳扑浪创新科技有限公司
Priority date: 2020-12-21
Filing date: 2021-03-04
Publication date: 2022-06-30
Also published as: CN112505962A

Abstract

The present invention relates to a display device, a manufacturing method therefor and a use thereof. The display device comprises a blue light backlight, a first polarizer, a quantum dot light-emitting layer, a liquid crystal layer and a second polarizer which are stacked in sequence, wherein the quantum dot light-emitting layer comprises at least two display units, each display unit comprises a first light-emitting unit, a second light-emitting unit and a third light-emitting unit which are arranged side by side in sequence, the first light-emitting unit is composed of a first transparent conductive layer and a green light quantum dot deposition layer which are stacked, the second light-emitting unit is composed of a second transparent conductive layer and a red light quantum dot deposition layer which are stacked, the first transparent conductive layer and the second transparent conductive layer are close to the first polarizer, and the third light-emitting unit is a third transparent conductive layer.

Description

A display device and its preparation method and application

technical field

The present application relates to the field of liquid crystal display, and relates to a display device and a preparation method and application thereof.

Background technique

With the rapid development of display technology, it is crucial to develop liquid crystal display devices with high resolution and color gamut values. Due to the quantum confinement of electrons and holes in quantum dots, the continuous energy band structure becomes a discrete energy level structure, so the luminescence spectrum is very narrow (20-30nm), the chromaticity is high, and the display color gamut is wide, which can greatly exceed that of NTSC. Color gamut range (>100%); at the same time, the light absorption loss through the color filter is small, which can realize low power consumption display. Therefore, currently, quantum dot materials are widely used in liquid crystal display devices to improve the display performance of the devices.

CN108803130A discloses a quantum dot liquid crystal display panel and a manufacturing method. The disclosed quantum dot liquid crystal display panel includes a first polarizer, a liquid crystal cell panel, a quantum dot layer, a protective layer and a second polarizer. The disclosed quantum dot liquid crystal display panel The display panel arranges the protective layer under the quantum dot layer and forms a space wrapping the second polarizer and the quantum dot layer, and the array substrate is arranged between the second alignment layer and the second polarizer, which solves the problem of water vapor and oxygen. cause the problem of quantum dot failure and can drastically reduce manufacturing costs. However, in this invention, the use of optical filters is unavoidable, and the luminous efficiency is low.

CN207992648U discloses a quantum dot liquid crystal panel and a display device. The disclosed quantum dot liquid crystal panel includes a color filter substrate, a liquid crystal layer, and an array substrate. The liquid crystal layer is disposed between the color filter substrate and the array substrate. In the meantime, the color filter substrate includes a blue light absorber, a base substrate, a pixel unit layer, and an encapsulation layer that are stacked in layers, and the pixel unit layer includes a red sub-pixel unit, a green sub-pixel unit, and a blue sub-pixel unit. The blue light absorber covers the red sub-pixel unit and the green sub-pixel unit. This setting method can improve the color purity of the quantum dot liquid crystal display panel, emit purer red and green light, and improve color saturation, but this method has relatively many components, complicated preparation, and relatively poor process magnification.

Therefore, it is very important to develop a liquid crystal display device with simple process, low cost, good coating effect and high display light efficiency.

SUMMARY OF THE INVENTION

The purpose of the present application is to provide a display device, a preparation method and an application thereof, the display device has simple process, low cost, good coating effect and high display light efficiency.

For this purpose, the application adopts the following technical solutions:

In a first aspect, the present application provides a display device, the display device includes a blue light backlight, a first polarizer, a quantum dot light-emitting layer, a liquid crystal layer and a second polarizer that are stacked in sequence;

The quantum dot light-emitting layer includes at least two display units (for example, 3, 5, 10, etc.), and the display units include a first light-emitting unit, a second light-emitting unit and a third light-emitting unit arranged side by side in sequence;

The first light-emitting unit is composed of a stacked first transparent conductive layer and a green quantum dot deposition layer, and the first transparent conductive layer is close to the first polarizer;

The second light-emitting unit is composed of a stacked second transparent conductive layer and a red quantum dot deposition layer, and the second transparent conductive layer is close to the first polarizer;

The third light-emitting unit is a third transparent conductive layer.

Different from the traditional LCD liquid crystal display device that uses a white LED light source and a color filter to achieve full-color display of three primary colors, the display device described in this application uses a blue backlight to excite the patterned red and green quantum dot deposition layers, without the need for color filters. The waveband filtering of the light sheet can realize full-color display with high light efficiency and ultra-high color gamut.

Optionally, the liquid crystal layer includes two layers of glass substrates, a TFT array, scan electrodes, signal electrodes, pixel electrodes, and liquid crystal molecules sandwiched between the two layers of substrates.

Optionally, the blue light source includes LED chips.

Optionally, the LED chip is epitaxially formed of gallium nitride (GaN).

Optionally, the emission peak wavelength of the blue LED chip is 420-480 nm, such as 430 nm, 440 nm, 450 nm, 460 nm, 470 nm, 480 nm, and the like.

Optionally, the length and width of the LED chips are independently 1-50 μm, such as 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, and the like.

Optionally, the quantum dot deposition substrate includes a glass substrate.

Optionally, the red light quantum dot deposition layer includes a red light quantum dot material.

Optionally, the green light quantum dot deposition layer includes a green light quantum dot material.

Optionally, the red light quantum dot material and the green light quantum dot material independently include an A _x _My E _z system material, a coating layer material and a ligand material sequentially coated on the surface of the A _x _My E _z system material. , the x is 0.3-2.0, such as 0.5, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, etc., y is 0.5-3.0, such as 1.0, 1.5, 2.0, 2.5, etc., z is 0-4.0, such as 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, etc.;

Described A is any one in Ba, Ag, Na, Fe, In, Cd, Zn, Ga, Mg, Pb or Cs;

Described M is any one in S, Cl, O, As, N, P, Se, Te, Ti, Zr or Pb;

The E is any one of S, As, Se, O, Cl, Br or I.

Optionally, the A _x _{My E z} _system material includes any one or a combination of at least two of GaN, CdSe, InP or CsPbBr ₃ , wherein a typical but non-limiting combination includes: a combination of GaN and CdSe , a combination of CdSe, InP and CsPbBr ₃ , a combination of GaN, CdSe, InP and CsPbBr ₃ , etc.

Optionally, the A _x _My E _z system material in the blue light quantum dot material includes CdSe.

CdSe has high luminous efficiency and narrow half-wave width, which can further improve the color gamut of display devices and reduce device power consumption.

Optionally, the coating material includes an organic polymer solution and/or an inorganic compound.

Optionally, the organic polymer solution comprises any one or a combination of at least two of polyoctadecene, polypropylene glycol methyl ether acetate (PMA) or polyvinylidene fluoride (PVDF), wherein typical but not limited Generic combinations include the combination of octadecene and PMA, the combination of PMA and PVDF, the combination of octadecene, PMA and PVDF, and the like.

Optionally, the inorganic compound includes any one or at least two of silicon dioxide (SiO ₂ ), titanium dioxide (TiO ₂ ), zirconium dioxide (ZrO ₂ ), zinc oxide (ZnO) or zinc sulfide (ZnS). A combination of species, wherein typical but non-limiting combinations include: a combination of SiO ₂ and ZnS, a combination of TiO ₂ and ZrO ₂ , a combination of ZrO ₂ and ZnO, a combination of TiO ₂ , ZrO ₂ and ZnO, and the like.

Optionally, the ligand material includes an organic salt.

Optionally, the organic salt includes any one or a combination of at least two of sodium acetate, bipyridate, sodium ethoxide, tetrabutylammonium bromide, ammonium bromide, ammonium chloride or ammonium sulfate, Typical but non-limiting combinations include: a combination of sodium acetate and epyridate, a combination of sodium ethoxide, tetrabutylammonium bromide and ammonium bromide, tetrabutylammonium bromide, ammonium bromide, ammonium chloride Combination of Ammonium and Ammonium Sulfate, Epyridate, Sodium Ethylate, Tetrabutylammonium Bromide, Combination of Ammonium Bromide and Ammonium Chloride, Sodium Acetate, Epyridate, Sodium Ethylate, Tetrabutylammonium Bromide Salt, combination of ammonium bromide and ammonium chloride, sodium acetate, bipyridate, sodium ethoxide, tetrabutylammonium bromide, ammonium bromide, combination of ammonium chloride and ammonium sulfate, etc.

Optionally, the particle size of the red light quantum dot material is 7-12 nm, such as 8 nm, 9 nm, 10 nm, 11 nm, 12 nm and the like.

Optionally, the particle size of the green light quantum dot material is 3-7 nm, such as 4 nm, 5 nm, 6 nm, and the like.

Optionally, the emission peak wavelength of the red quantum dot material is 600-660 nm, for example, 610 nm, 620 nm, 630 nm, 640 nm, 650 nm, and the like.

Optionally, the emission peak wavelength of the green quantum dot material is 510-550 nm, such as 520 nm, 530 nm, 540 nm, and the like.

Optionally, the emission light half-peak width of the red light quantum dot material is less than 35 nm, for example, 30 nm, 25 nm, 20 nm, 15 nm, and the like.

Optionally, the emission light half-peak width of the green quantum dot material is <35 nm, for example, 30 nm, 25 nm, 20 nm, 15 nm, and the like.

Optionally, the display device further includes a screen glass attached to the surface of the second polarizer.

In a second aspect, the present application provides a preparation method of the display device according to the first aspect, the preparation method includes the following steps: firstly, coating a transparent conductive material on a quantum dot deposition substrate to form first transparent conductive materials arranged side by side in sequence The conductive layer, the second transparent conductive layer and the third transparent conductive layer, and then the green light quantum dot electrodeposition solution and the red light quantum dot electrodeposition solution are deposited on the first transparent conductive layer and the second transparent conductive layer respectively by the method of electrodeposition. , to obtain a quantum dot light-emitting layer, and finally, the first polarizer, the quantum dot light-emitting layer, the liquid crystal layer and the second polarizer are sequentially stacked and pasted on the blue light backlight source.

The present application adopts the electrodeposition method to prepare the quantum dot light-emitting layer. The method is simple and easy to operate, has low production cost, and can deposit the quantum dot material at a designated position as required, and realizes pixel-level coating at the same time, with high display resolution. , while canceling the use of filters, greatly improving the light efficiency of the display device.

Optionally, the preparation method comprises the steps:

(1) Synthesize the A _x _My E _z system material by solution method in the reaction solvent, and then sequentially add the coating material and the ligand material to continue the reaction to obtain a red light quantum dot electrodeposition solution or a green light quantum dot electrodeposition solution. ;

(2) coating the transparent conductive material on the glass substrate and etching to obtain the quantum dot deposition substrate;

(3) depositing the red light quantum dot electrodeposition solution and the green light quantum dot electrodeposition solution in the respective deposition regions on the quantum dot deposition substrate to obtain a quantum light-emitting layer;

(4) The first polarizer, the quantum light-emitting layer, the liquid crystal layer, the second polarizer and the screen glass are successively stacked and pasted on the blue light source to obtain the display device.

Optionally, the reaction solvent includes any one or a combination of at least two of oleylamine, oleic acid or long-chain phosphonic acid, wherein typical but non-limiting combinations include: a combination of oleylamine and oleic acid, oleylamine and long-chain phosphonic acid, oleylamine, oleic acid and long-chain phosphonic acid, etc.

Optionally, the step (1) specifically includes:

a. Synthesize the A _x _My E _z system material by solution method in the reaction solvent, drop the coating material to obtain the core-shell structure red light quantum dot material, after purification, place the core-shell structure red light quantum dot material in the In the solvent, a ligand material is added to generate a bonding reaction to obtain a charged core-shell type red quantum dot electrodeposition solution;

b. Synthesize the A _x _My E _z system material by the solution method in the reaction solvent, drop the coating material to obtain the green quantum dot material with the core-shell structure, and then place the core-shell structure green quantum dot material in the solution after purification. In the solvent, a ligand material is added to generate a bonding reaction to obtain a charged core-shell type green quantum dot electrodeposition solution.

Optionally, the pH of the bonding reaction in the step (1) is 5.5-11, such as 6, 7, 8, 9, 10 and the like.

Optionally, the temperature of the bonding reaction in the step (1) is 120-320°C, such as 150°C, 200°C, 250°C, 300°C, and the like.

Optionally, the time for the bonding reaction in the step (1) is 0.5-35 min, such as 5 min, 10 min, 15 min, 20 min, 25 min, and the like.

Optionally, the transparent conductive material comprises aluminum-doped zinc oxide (AZO), tin-doped indium trioxide (ITO), fluorine-doped tin dioxide (FTO) or graphene-deposited polyethylene terephthalate Any one or a combination of at least two of the alcohol ester PET.

The transparent conductive material of the present application can be selected from ITO or graphene-deposited PET, because ITO or graphene-deposited PET has high light transmittance and low resistivity.

Optionally, the step (2) specifically includes:

c. Coating the transparent conductive material on the glass substrate and curing to obtain the coated glass substrate;

d. Coating an anti-etching material on the first light-emitting unit area, the second light-emitting unit area and the third light-emitting unit area, and performing etching outside the light-emitting unit area;

e. Strip and clean the anti-etching material on the etched glass substrate;

f. Install a circuit on the glass substrate obtained in step e to connect the first light emitting unit regions to each other to achieve electrical conduction, and to connect the second light emitting unit regions to each other to achieve electrical conduction to obtain a quantum dot deposition substrate.

Optionally, the coating method includes any one of magnetron sputtering, vacuum evaporation or sol-gel spin coating.

Optionally, the etching includes chemical etching or physical etching.

Optionally, the cleaning includes any one or a combination of at least two of organic solution cleaning, water cleaning or plasma cleaning (Plasma), wherein typical but non-limiting combinations include: organic solution cleaning and water cleaning Combination, combination of water cleaning and Plasma cleaning, organic solution cleaning, combination of water cleaning and Plasma cleaning, etc.

Optionally, the step (3) specifically includes:

g. placing the quantum dot deposition substrate in a green quantum dot electrodeposition solution;

H. connect the first light-emitting unit region and electrode with the DC power supply, and energize, under the action of the electric field, the green light quantum dot material is self-deposited in the corresponding region to obtain the quantum dot deposition substrate containing the green light quantum dot deposition layer;

i. placing the quantum dot deposition substrate obtained in step h in the red light quantum dot electrodeposition solution;

j. Connect the second light-emitting unit region and electrode to the DC power supply electrode, and energize. Under the action of the electric field, the red light quantum dot material is self-deposited in the corresponding region, and the deposited quantum dot deposition substrate is taken out, dried, sprayed and packaged. Glue and solidify to obtain a quantum dot light-emitting layer.

Optionally, the anti-etching material includes any one or a combination of at least two of a metal coating, an oxide coating or an organic masking layer, wherein a typical but non-limiting combination includes: a combination of a metal coating and an oxide coating , combination of oxide coating and organic masking layer, metal coating, combination of oxide coating and organic masking layer, etc.

Optionally, the encapsulation glue includes any one or a combination of at least two of epoxy resin, silicone resin or polyurethane, wherein a typical but non-limiting combination is: a combination of silicone resin and epoxy resin, silicone resin Combination of resin and polyurethane, silicone resin, combination of epoxy resin and polyurethane, etc.

Optionally, the step (4) specifically includes: sequentially stacking the first polarizer, the quantum dot light-emitting layer, the liquid crystal layer, the second polarizer and the screen glass on the blue light source to obtain a display device.

As an optional technical solution, the preparation method comprises the following steps:

(1) Preparation of quantum dot electrodeposition solution

a. Synthesize the A _x _My E _z system material by solution method in the reaction solvent, drop the coating material to obtain the core-shell structure red light quantum dot material, after purification, place the core-shell structure red light quantum dot material in the In the solvent, the ligand material is added, the pH is adjusted to 5.5-11, the temperature is 120-320 ° C, and the bonding reaction is carried out for 0.5-35 min to obtain a charged core-shell type red quantum dot electrodeposition solution;

b. Synthesize the A _x _My E _z system material by the solution method in the reaction solvent, drop the coating material to obtain the green quantum dot material with the core-shell structure, and then place the core-shell structure green quantum dot material in the solution after purification. In the solvent, the ligand material is added, the pH is adjusted to 5.5-11, the temperature is 120-320 ° C, and the bonding reaction is carried out for 0.5-35 min to obtain a charged core-shell type green light quantum dot electrodeposition solution;

(2) Preparation of quantum dot deposition substrate

c. Coating a transparent conductive material on a glass substrate by magnetron sputtering, vacuum evaporation or sol-gel spin coating, and curing to obtain a coated glass substrate;

e. Strip and clean the anti-etching material on the etched glass substrate;

f. installing a circuit on the glass substrate obtained in step e to connect the first light-emitting unit regions to each other to achieve electrical conduction, and to connect the second light-emitting unit regions to each other to achieve electrical conduction to obtain a quantum dot deposition substrate;

(3) Preparation of quantum dot light-emitting layer

h. The first light-emitting unit region and electrode are connected to the DC power supply electrode, and the power is turned on. Under the action of the electric field, the green light quantum dot material is self-deposited in the corresponding region to obtain a quantum dot deposition substrate containing a green light quantum dot deposition layer;

j. The second light-emitting unit area and electrode are connected to the DC power supply electrode and electrified. Under the action of the electric field, the red light quantum dot material is self-deposited in the corresponding area, and the deposited quantum dot deposition substrate is taken out, dried, and sprayed with encapsulation glue. , solidified to obtain a quantum dot light-emitting layer;

(4) Preparation of display devices

k. Laminate the first polarizer, the quantum dot light-emitting layer, the liquid crystal layer, the second polarizer and the screen glass sequentially on the blue light backlight to obtain a display device.

In a third aspect, the present application provides an application of the display device according to the first aspect in an LCD display device.

Compared with the prior art, the present application has the following beneficial effects:

Compared with the traditional LCD liquid crystal display device, the display device described in the present application uses the blue light source to excite the red light and green light quantum dot deposition layers, and realizes ultra-high color gamut display by compounding. The light conversion efficiency of the display device obtained in the present application is over 86%, the lifetime of the optical layer L70 is over 24,500 hours, the color gamut value of the display device is over 118%, and has excellent features of high reliability and durability.

Description of drawings

1 is a schematic structural diagram of a display device provided in Embodiment 1 of the present application;

2 is a structural diagram of a quantum dot deposition substrate provided in Example 1;

3 is a schematic diagram of the quantum dot light-emitting layer provided in Example 1;

4 is a schematic diagram of the electrodeposition process of quantum dots provided in Example 1;

5 is a schematic diagram of the working process of the display device provided in Embodiment 1;

Among them, 1-first light-emitting unit, 2-second light-emitting unit, 3-third light-emitting unit, 10-blue light source, 20-first polarizer, 30-quantum dot light-emitting layer, 40-liquid crystal layer, 50- Second polarizer, 60-screen glass, 301-quantum dot deposition glass substrate, 302-transparent conductive layer, 303-red quantum dot deposition layer, 304-green quantum dot deposition layer, 305-first transparent conductive layer, 306- The second transparent conductive layer, 701 - blue light emitted by a blue light backlight, 702 - red light converted by the red light quantum dot deposition layer, 703 - green light converted by the green light quantum dot deposition layer.

Detailed ways

In order to facilitate the understanding of the present application, the present application lists the following examples. It should be understood by those skilled in the art that the embodiments are only for helping the understanding of the present application, and should not be regarded as a specific limitation of the present application.

Example 1

This embodiment provides a display device, as shown in FIG. 1 , the display device includes a blue light backlight 10 , a first polarizer 20 , a quantum dot light-emitting layer 30 , a liquid crystal layer 40 , and a second polarizer 50 and screen glass 60;

The quantum dot light-emitting layer includes at least two display units, and the display units include a first light-emitting unit 1, a second light-emitting unit 2, and a third light-emitting unit 3 (as shown in FIG. 5) arranged side by side;

The first light-emitting unit is composed of a stacked first transparent conductive layer 305 and a green quantum dot deposition layer 303 (thickness is 75 μm);

The second light-emitting unit is composed of a stacked second transparent conductive layer 306 and a red quantum dot deposition layer 304 (thickness is 35 μm);

The third light-emitting unit is a third transparent conductive layer.

This embodiment also provides a preparation method of the above-mentioned display device, and the preparation method includes the following steps:

(1) Preparation of quantum dot electrodeposition solution

a. Synthesize InP by solution method in oleylamine, add ZnO dropwise to obtain a core-shell structure red light quantum dot material (particle size is 10nm, luminescence peak wavelength is 630nm), after purification, the core-shell structure red light quantum dot material Put it in n-hexane, add sodium ethoxide, adjust the pH to 6, the temperature is 220 ° C, and carry out the bonding reaction for 20 min to obtain a charged core-shell red quantum dot electrodeposition solution;

b. Synthesize CsPbBr ₃ by solution method in oleylamine, add ZnO dropwise to obtain green quantum dot material with core-shell structure (particle size is 5nm, luminescence peak wavelength is 530nm), after purification, core-shell structure green quantum dots are obtained The material was placed in n-hexane, sodium ethoxide was added, the pH was adjusted to 6, the temperature was 220 °C, and the bonding reaction was carried out for 20 min to obtain a charged core-shell green quantum dot electrodeposition solution;

(2) Preparation of quantum dot deposition substrate

c. Coating ITO on the glass substrate by the method of magnetron sputtering, curing, forming the transparent conductive layer 302, and obtaining the coated glass substrate;

d. Coating the metal plating layer (Ni) on the first light-emitting unit area, the second light-emitting unit area and the third light-emitting unit area, and performing strong alkali solution etching outside the light-emitting unit area;

e. The metal coating (Ni) on the etched glass substrate is peeled off and washed with water;

f. a circuit is installed on the glass substrate obtained in step e, so that the first light-emitting unit regions are connected to each other to achieve electrical conduction, and the second light-emitting unit regions are connected to each other to achieve electrical conduction to obtain a quantum dot deposition substrate 301 (as shown in FIG. 2 ). Show);

(3) Preparation of quantum dot light-emitting layer

j. The second light-emitting unit area and electrode are connected to the DC power supply electrode, and the power is turned on. Under the action of the electric field, the red light quantum dot material is self-deposited in the corresponding area, and the deposited quantum dot deposition substrate is taken out, dried, and sprayed with methyl The phenyl silicone resin is cured to obtain a quantum dot light-emitting layer (the quantum dot light-emitting layer is shown in Figure 3, and the quantum dot electrodeposition process is shown in Figure 4);

(4) Preparation of display devices

k. Laminate the first polarizer, the quantum dot light-emitting layer, the liquid crystal layer, the second polarizer and the screen glass on the blue light source in turn to obtain a display device (the schematic diagram of the working process of the display device is shown in Figure 5, and the blue light is turned on) The backlight source emits blue light 701 through the first polarizer, and passes through the quantum dot light-emitting layer to obtain red light 702 converted by the red quantum dot deposition layer and green light 703 converted by the green quantum dot deposition layer to achieve full color. show).

Example 2

This embodiment provides a display device, the display device includes a blue light backlight, a first polarizer, a quantum dot light-emitting layer, a liquid crystal layer, a second polarizer, and a screen glass;

The quantum dot light-emitting layer includes at least two display units, the display units include a first light-emitting unit, a second light-emitting unit and a third light-emitting unit arranged side by side;

The first light-emitting unit is composed of a stacked first transparent conductive layer and a green quantum dot deposition layer (with a thickness of 150 μm);

The second light-emitting unit is composed of a stacked second transparent conductive layer and a red light quantum dot deposition layer (70 μm in thickness);

The third light-emitting unit is a third transparent conductive layer.

(1) Preparation of quantum dot electrodeposition solution

a. Synthesize CdSe by solution method in long-chain phosphonic acid, add PVDF dropwise to obtain core-shell structure red quantum dot material (particle size is 7nm, luminescence peak wavelength is 600nm), after purification, core-shell structure red light quantum dot material is obtained The dot material was placed in n-octane, sodium acetate was added, the pH was adjusted to 11, the temperature was 320°C, and the bonding reaction was carried out for 0.5 min to obtain a charged core-shell red quantum dot electrodeposition solution;

b. Synthesize GaN by solution method in long-chain phosphonic acid, add ZnS dropwise to obtain green light quantum dot material with core-shell structure (particle size is 3nm, luminescence peak wavelength is 510nm), after purification, the core-shell structure green light quantum dot material is obtained The dot material was placed in n-octane, sodium acetate was added, the pH was adjusted to 11, the temperature was 320 °C, and the bonding reaction was carried out for 0.5 min to obtain a charged core-shell green quantum dot electrodeposition solution;

(2) Preparation of quantum dot deposition substrate

c. Coating graphene to deposit PET on a glass substrate by sol-gel spin coating, and curing to obtain a coated glass substrate;

d. Coating an oxide plating layer (Cr ₂ O ₃ ) on the first light-emitting unit area, the second light-emitting unit area and the third light-emitting unit area, and performing chemical etching outside the light-emitting unit area;

e. peel off and clean the oxide coating (Cr ₂ O ₃ ) on the etched glass substrate;

(3) Preparation of quantum dot light-emitting layer

j. The second light-emitting unit area and electrode are connected to the DC power supply electrode, and the power is turned on. Under the action of the electric field, the red light quantum dot material is self-deposited in the corresponding area, and the deposited quantum dot deposition substrate is taken out, dried, and sprayed with polyurethane. curing to obtain a quantum dot light-emitting layer;

(4) Preparation of display devices

k. Laminate the first polarizer, the quantum dot light-emitting layer, the liquid crystal layer, the second polarizer and the screen glass sequentially on the blue light source to obtain a display device.

Example 3

The first light-emitting unit is composed of a stacked first transparent conductive layer and a green quantum dot deposition layer (with a thickness of 2 μm);

The second light-emitting unit is composed of a stacked second transparent conductive layer and a red light quantum dot deposition layer (thickness is 1 μm);

The third light-emitting unit is a third transparent conductive layer.

(1) Preparation of quantum dot electrodeposition solution

a. Dissolve CdSe in oleylamine by solution method, add PVDF dropwise to obtain core-shell structure red quantum dot material (particle size is 12nm, luminescence peak wavelength is 660nm), after purification, core-shell structure red light quantum dots are obtained The material was placed in toluene, tetrabutylammonium bromide was added, the pH was adjusted to 5.5, the temperature was 120 °C, and the bonding reaction was carried out for 35 minutes to obtain a charged core-shell red quantum dot electrodeposition solution;

b. Synthesize GaN by solution method in oleic acid, add ZnS dropwise to obtain green quantum dot material with core-shell structure (particle size is 3 nm, luminescence peak wavelength is 550 nm), after purification, the core-shell structure green light quantum dot material is obtained Place in chloroform, add ammonium sulfate, adjust pH to 8, temperature to 120°C, and carry out bonding reaction for 35min to obtain charged core-shell type green quantum dot electrodeposition solution;

(2) Preparation of quantum dot deposition substrate

c. Coating AZO on the glass substrate by vacuum evaporation, and curing to obtain the coated glass substrate;

d. Coat the organic masking layer (paraffin) on the first light-emitting unit area, the second light-emitting unit area and the third light-emitting unit area, and perform HF strong acid etching outside the light-emitting unit area;

e. The organic masking layer (paraffin) on the etched glass substrate is peeled off, and the organic solution is cleaned;

(3) Preparation of quantum dot light-emitting layer

(4) Preparation of display devices

Example 4

The first light-emitting unit is composed of a stacked first transparent conductive layer and a green quantum dot deposition layer (thickness is 40 μm);

The second light-emitting unit is composed of a stacked second transparent conductive layer and a red light quantum dot deposition layer (with a thickness of 20 μm);

The third light-emitting unit is a third transparent conductive layer.

(1) Preparation of quantum dot electrodeposition solution

a. Synthesize CdSe by solution method in oleylamine, add PVDF dropwise to obtain the core-shell structure red quantum dot material (particle size is 8nm, luminescence peak wavelength is 620nm), after purification, the core-shell structure red light quantum dot material Place in toluene, add ammonium bromide, adjust pH to 5.5, temperature to 280°C, and carry out bonding reaction for 15min to obtain charged core-shell red quantum dot electrodeposition solution;

b. Synthesize GaN by solution method in oleic acid, add ZnS dropwise to obtain a green quantum dot material with a core-shell structure (particle size is 6 nm, luminescence peak wavelength is 530 nm), and after purification, the green quantum dot material with a core-shell structure is obtained Place in chloroform, add sodium acetate, adjust pH to 8, temperature to 280°C, carry out bonding reaction for 15min, and obtain charged core-shell type green quantum dot electrodeposition solution;

(2) Preparation of quantum dot deposition substrate

c. Coating the FTO dispersed in the photoresist on the glass substrate by the method of vacuum evaporation, and curing to obtain the coated glass substrate;

d. Coat the organic masking layer (triarylmethane solution) on the first light-emitting unit area, the second light-emitting unit area and the third light-emitting unit area, and perform ultraviolet lithography outside the light-emitting unit area;

e. peeling off the organic masking layer (triarylmethane solution) on the etched glass substrate and cleaning with the organic solution;

(3) Preparation of quantum dot light-emitting layer

(4) Preparation of display devices

Example 5

The first light-emitting unit is composed of a stacked first transparent conductive layer and a green quantum dot deposition layer (with a thickness of 120 μm);

The second light-emitting unit is composed of a stacked second transparent conductive layer and a red light quantum dot deposition layer (with a thickness of 60 μm);

The third light-emitting unit is a third transparent conductive layer.

(1) Preparation of quantum dot electrodeposition solution

a. Synthesize CdSe by solution method in oleylamine, add PMA dropwise to obtain a core-shell structure red quantum dot material (particle size is 9nm, luminescence peak wavelength is 640nm), after purification, the core-shell structure red light quantum dot material Put it in toluene, add sodium ethoxide, adjust the pH to 6.5, the temperature is 200°C, and carry out the bonding reaction for 25min to obtain a charged core-shell type red quantum dot electrodeposition solution;

b. Synthesize GaN by solution method in oleic acid, add ZnS dropwise to obtain a green quantum dot material with a core-shell structure (particle size is 4 nm, luminescence peak wavelength is 540 nm), and after purification, the green quantum dot material with a core-shell structure is obtained. Place in chloroform, add ammonium chloride, adjust pH to 8, temperature to 200°C, and carry out bonding reaction for 25min to obtain charged core-shell type green quantum dot electrodeposition solution;

(2) Preparation of quantum dot deposition substrate

c. Coating the ITO dispersed in the photoresist on the glass substrate by the method of vacuum evaporation, and curing to obtain the coated glass substrate;

d. applying an organic masking layer (quinacridone solution) to the first light-emitting unit area, the second light-emitting unit area and the third light-emitting unit area, and performing ultraviolet lithography outside the light-emitting unit area;

e. peeling off the organic masking layer (quinacridone solution) on the etched glass substrate and cleaning with the organic solution;

(3) Preparation of quantum dot light-emitting layer

(4) Preparation of display devices

Comparative Example 1

The difference between this comparative example and Example 1 is that this comparative example adopts conventional means to prepare the quantum dot optical layer, and the obtained display device further includes a filter.

The preparation method of the display device of this comparative example comprises the following steps:

(1) Mix the red and green quantum dot materials into the acrylic glue and stir evenly;

(2) the obtained red and green quantum dot mixed glue is coated between two layers of PET films, and is attached;

(3) the obtained PET film coated with quantum dot glue is placed in an ultraviolet curing box, and the acrylic glue is cured under 385nm ultraviolet light;

(4) Cut the diaphragm according to the size of the display screen to obtain the quantum dot light-emitting layer;

(5) Preparation of display devices

The light guide plate, the quantum dot light-emitting layer, the first polarizer, the liquid crystal layer, the second polarizer, the filter and the screen glass are laminated and pasted on the light source in sequence to obtain a quantum dot display device.

Performance Testing

Performance test of quantum dot optical film:

(1) Test of light conversion efficiency: light conversion efficiency=emission light power of quantum dot film/excitation light power of blue light backlight×100%.

(2) Life of the optical film L70: that is, the working time until the luminous intensity decays to 70% of the initial value under normal temperature lighting (25°C), and the brightness parameter nit of the display device is used.

Display device performance test:

(3) Display device color gamut value: according to the NTSC standard.

The above test results are shown in Table 1:

Table 1

	光转化效率/％Light Conversion Efficiency/%	发光层L70寿命/小时Light-emitting layer L70 life/hour	显示器件色域值/％Display device color gamut value/%
实施例1Example 1	8888	2450024500	119119
实施例2Example 2	9090	2620026200	121121
实施例3Example 3	8787	3100031000	123123
实施例4Example 4	8686	2830028300	120120
实施例5Example 5	8888	2750027500	118118
对比例1Comparative Example 1	3131	1450014500	104104

The display device described in the present application does not need to rely on a filter when used, which is beneficial to improve the light transmission rate and display light efficiency, and the overall power consumption of the display device is low. From the data in Table 1, the light conversion efficiency is above 86%, the life of the optical layer L70 is above 24,500 hours, and the color gamut value of the display device is above 118%, with excellent features of high reliability and durability.

From the analysis of Comparative Example 1 and Example 1, it can be found that the light conversion efficiency of Comparative Example 1 is 31%, the life of the optical layer L70 is only 14500 hours, and the color gamut value of the display device is 104%, and the parameters are all worse than Example 1, It is proved that the quantum dot light-emitting layer obtained by the preparation method of the quantum dot optical layer described in the present application has excellent performance.

To sum up, the display device described in the present application does not need to rely on optical filters when used, which is beneficial to improve the light transmission rate and display light efficiency. Therefore, the overall power consumption of the display device is low, and the display device has both high reliability and durability. Excellent features.

The applicant declares that the present application illustrates the detailed method of the present application through the above-mentioned embodiments, but the present application is not limited to the above-mentioned detailed method, which does not mean that the present application must rely on the above-mentioned detailed method for implementation.

Claims

A display device, comprising a blue light backlight, a first polarizer, a quantum dot light-emitting layer, a liquid crystal layer and a second polarizer, which are stacked in sequence;

The quantum dot light-emitting layer includes at least two display units, and the display units include a first light-emitting unit, a second light-emitting unit and a third light-emitting unit arranged side by side in sequence;

The first light-emitting unit is composed of a stacked first transparent conductive layer and a green quantum dot deposition layer, and the first transparent conductive layer is close to the first polarizer;

The second light-emitting unit is composed of a stacked second transparent conductive layer and a red quantum dot deposition layer, and the second transparent conductive layer is close to the first polarizer;

The third light-emitting unit is a third transparent conductive layer.
The display device of claim 1, wherein the blue light source comprises an LED chip.
The display device of claim 2, wherein the LED chip is epitaxially formed of gallium nitride.
The display device according to claim 2 or 3, wherein the length and width of the LED chip are each independently 1-50 μm;

Optionally, the light emission peak wavelength of the LED chip is 420-480 nm.
The display device of any one of claims 1-4, wherein the quantum dot deposition substrate comprises a glass substrate.
The display device according to any one of claims 1-5, wherein the red light quantum dot deposition layer comprises a red light quantum dot material;

Optionally, the green light quantum dot deposition layer includes a green light quantum dot material;

Optionally, the red light quantum dot material and the green light quantum dot material independently include an A x My E z system material, a coating layer material and a ligand material sequentially coated on the surface of the A x My E z system material. , the x is 0.3-2.0, y is 0.5-3.0, and z is 0-4.0;

Described A is any one in Ba, Ag, Na, Fe, In, Cd, Zn, Ga, Mg, Pb or Cs;

Described M is any one in S, Cl, O, As, N, P, Se, Te, Ti, Zr or Pb;

Described E is any one in S, As, Se, O, Cl, Br or I;

Optionally, the A x My E z system material includes any one or a combination of at least two of GaN, CdSe, InP or CsPbBr ;

Optionally, the coating material includes an organic polymer solution and/or an inorganic compound;

Optionally, the ligand material includes an organic salt;

Optionally, the organic salt includes any one or a combination of at least two of sodium acetate, pyridoxate, sodium ethoxide, tetrabutylammonium bromide, ammonium bromide, ammonium chloride or ammonium sulfate.
The display device according to claim 6, wherein the particle size of the red quantum dot material is 7-12 nm;

Optionally, the particle size of the green quantum dot material is 3-7nm;

Optionally, the luminescence peak wavelength of the red quantum dot material is 600-660 nm;

Optionally, the luminescence peak wavelength of the green quantum dot material is 510-550 nm;

Optionally, the emission light half-peak width of the red light quantum dot material is less than 35 nm;

Optionally, the emission light half-peak width of the green quantum dot material is less than 35 nm.
The display device according to any one of claims 1-7, wherein the display device further comprises a screen glass attached to the surface of the second polarizer.
A method for preparing a display device according to any one of claims 1-8, comprising the steps of:

First, the transparent conductive material is coated on the quantum dot deposition substrate to form the first transparent conductive layer, the second transparent conductive layer and the third transparent conductive layer arranged side by side, and then the green light quantum dot electrodeposition solution and the red light quantum dot electrodeposition are electrodeposited The solution is deposited on the first transparent conductive layer and the second transparent conductive layer respectively by the method of electrodeposition to obtain the quantum dot light-emitting layer, and finally the first polarizer, the quantum dot light-emitting layer, the liquid crystal layer and the second polarizer are stacked and pasted in sequence overlaid on the blue light source.
The preparation method of a display device according to claim 9, wherein the preparation method comprises the steps of:

(1) Synthesize the A x My E z system material by solution method in the reaction solvent, and then sequentially add the coating material and the ligand material to continue the reaction to obtain a red light quantum dot electrodeposition solution or a green light quantum dot electrodeposition solution. ;

(2) coating the transparent conductive material on the glass substrate and etching to obtain the quantum dot deposition substrate;

(3) depositing the red light quantum dot electrodeposition solution and the green light quantum dot electrodeposition solution in the respective deposition regions on the quantum dot deposition substrate to obtain a quantum light-emitting layer;

(4) laminating the first polarizer, the quantum light-emitting layer, the liquid crystal layer, the second polarizer and the screen glass on the blue light source in turn to obtain the display device;

Optionally, the reaction solvent comprises any one or a combination of at least two of oleylamine, oleic acid or long-chain phosphonic acid;

Optionally, the step (1) specifically includes:

a. Synthesize the A x My E z system material by solution method in the reaction solvent, drop the coating material to obtain the core-shell structure red light quantum dot material, after purification, place the core-shell structure red light quantum dot material in the In the solvent, a ligand material is added to generate a bonding reaction to obtain a charged core-shell type red quantum dot electrodeposition solution;

b. Synthesize the A x My E z system material by the solution method in the reaction solvent, drop the coating material to obtain the green quantum dot material with the core-shell structure, and then place the core-shell structure green quantum dot material in the solution after purification. In the solvent, a ligand material is added to generate a bonding reaction to obtain a charged core-shell type green quantum dot electrodeposition solution;

Optionally, the pH of the step (1) bonding reaction is 5.5-11;

Optionally, the temperature of the step (1) bonding reaction is 120-320°C;

Optionally, the time of the step (1) bonding reaction is 0.5-35min;

Optionally, the transparent conductive material includes any one or at least one of aluminum-doped zinc oxide, tin-doped indium trioxide, fluorine-doped tin dioxide, or graphene-deposited polyethylene terephthalate. a combination of the two;

Optionally, the step (2) specifically includes:

c. Coating the transparent conductive material on the glass substrate and curing to obtain the coated glass substrate;

d. Coating an anti-etching material on the first light-emitting unit area, the second light-emitting unit area and the third light-emitting unit area, and performing etching outside the light-emitting unit area;

e. Strip and clean the anti-etching material on the etched glass substrate;

f. installing a circuit on the glass substrate obtained in step e, so that the first light-emitting unit regions are connected to each other to achieve electrical conduction, and the second light-emitting unit regions are connected to each other to achieve electrical conduction to obtain a quantum dot deposition substrate;

Optionally, the coating method includes any one of magnetron sputtering, vacuum evaporation or sol-gel spin coating;

Optionally, the etching includes chemical etching or physical etching;

Optionally, the cleaning includes any one or a combination of at least two of organic solution cleaning, water cleaning or plasma cleaning;

Optionally, the step (3) specifically includes:

g. placing the quantum dot deposition substrate in a green quantum dot electrodeposition solution;

h. Connect the first light-emitting unit region and the electrode to the DC power supply, and energize, under the action of the electric field, the green light quantum dot material is self-deposited in the corresponding region to obtain a quantum dot deposition substrate containing a green light quantum dot deposition layer;

i. placing the quantum dot deposition substrate obtained in step h in the red light quantum dot electrodeposition solution;

j. Connect the second light-emitting unit area and electrode to the DC power supply electrode, and energize. Under the action of the electric field, the red light quantum dot material is self-deposited in the corresponding area, and the deposited quantum dot deposition substrate is taken out, dried, sprayed and packaged. Glue, solidify to obtain quantum dot light-emitting layer;

Optionally, the anti-etching material includes any one or a combination of at least two of a metal coating, an oxide coating or an organic masking layer;

Optionally, the encapsulation glue includes any one or a combination of at least two of epoxy resin, silicone resin or polyurethane;

Optionally, the step (4) specifically includes: sequentially stacking the first polarizer, the quantum dot light-emitting layer, the liquid crystal layer, the second polarizer and the screen glass on the blue light source to obtain a display device.
The preparation method of a display device according to claim 9 or 10, wherein the preparation method comprises the steps of:

(1) Preparation of quantum dot electrodeposition solution

a. Synthesize the A x My E z system material by solution method in the reaction solvent, drop the coating material to obtain the core-shell structure red light quantum dot material, after purification, place the core-shell structure red light quantum dot material in the In the solvent, the ligand material is added, the pH is adjusted to 5.5-11, the temperature is 120-320 ° C, and the bonding reaction is carried out for 0.5-35 min to obtain a charged core-shell type red quantum dot electrodeposition solution;

b. Synthesize the A x My E z system material by the solution method in the reaction solvent, drop the coating material to obtain the green quantum dot material with the core-shell structure, and then place the core-shell structure green quantum dot material in the solution after purification. In the solvent, the ligand material is added, the pH is adjusted to 5.5-11, the temperature is 120-320 ° C, and the bonding reaction is carried out for 0.5-35 min to obtain a charged core-shell type green light quantum dot electrodeposition solution;

(2) Preparation of quantum dot deposition substrate

c. Coating a transparent conductive material on a glass substrate by magnetron sputtering, vacuum evaporation or sol-gel spin coating, and curing to obtain a coated glass substrate;

d. Coating an anti-etching material on the first light-emitting unit area, the second light-emitting unit area and the third light-emitting unit area, and performing etching outside the light-emitting unit area;

e. Strip and clean the anti-etching material on the etched glass substrate;

f. installing a circuit on the glass substrate obtained in step e to connect the first light-emitting unit regions to each other to achieve electrical conduction, and to connect the second light-emitting unit regions to each other to achieve electrical conduction to obtain a quantum dot deposition substrate;

(3) Preparation of quantum dot light-emitting layer

g. placing the quantum dot deposition substrate in a green quantum dot electrodeposition solution;

h. The first light-emitting unit area and the electrode are connected to the DC power supply electrode, and the electricity is turned on. Under the action of the electric field, the green quantum dot material is self-deposited in the corresponding area, and the quantum dot deposition substrate containing the green quantum dot deposition layer is obtained;

i. placing the quantum dot deposition substrate obtained in step h in the red light quantum dot electrodeposition solution;

j. The second light-emitting unit area and electrode are connected to the DC power supply electrode and electrified. Under the action of the electric field, the red light quantum dot material is self-deposited in the corresponding area, and the deposited quantum dot deposition substrate is taken out, dried, and sprayed with encapsulation glue. , solidified to obtain a quantum dot light-emitting layer;

(4) Preparation of display devices

k. Laminate the first polarizer, the quantum dot light-emitting layer, the liquid crystal layer, the second polarizer and the screen glass sequentially on the blue light source to obtain a display device.
An application of the display device according to any one of claims 1-8 in an LCD display device.