WO2020037721A1

WO2020037721A1 - Quantum dot polarizer and manufacturing method therefor, liquid crystal panel, and electronic device

Info

Publication number: WO2020037721A1
Application number: PCT/CN2018/104488
Authority: WO
Inventors: 陈黎暄
Original assignee: 深圳市华星光电技术有限公司
Priority date: 2018-08-22
Filing date: 2018-09-07
Publication date: 2020-02-27
Also published as: CN108803129A

Abstract

A quantum dot polarizer, comprising a polarizing layer (3) and a compensation layer (4) adhered to one side of the polarizing layer (3) and comprising quantum dot nanorods (41) arranged directionally. A manufacturing method for a quantum dot polarizer, comprising: a material preparation step (S1), a coating step (S2), a pre-treatment step (S3), an inscription rubbing step (S4), and a curing step (S5). Also provided are a liquid crystal panel and an electronic device. The quantum dot nanorods are arranged directionally, and have strong polarity while the advantages of quantum dots are ensured, which significantly improves the optical efficiency.

Description

Quantum dot polarizer, preparation method thereof, liquid crystal panel and electronic device

Technical field

The present invention relates to the field of displays, and in particular, to a quantum dot polarizer, a preparation method thereof, a liquid crystal panel, and an electronic device.

Background technique

With the development of science and technology and the progress of society, people are increasingly relying on information exchange and transmission. As the main carrier and material basis for information exchange and transmission, display devices have become a hotspot and a high ground for many scientists engaged in information optoelectronics.

Quantum dots (QD) quasi-zero-dimensional nanomaterials, consisting of a small number of atoms, are extremely small inorganic nanocrystals that are invisible to the naked eye. Whenever stimulated by light or electricity, the quantum dots emit colored light. The color of the light is determined by the material and size of the quantum dots. Generally, the smaller the particle, the longer the wave, and the larger the particle, the shorter the wave. Quantum dots, which can absorb short-wave blue, excite a long-wavelength light color. This feature enables quantum dots to change the color of light emitted by a light source.

Quantum dot display technology has been comprehensively upgraded in various dimensions such as color gamut coverage, color control accuracy, red, green and blue color purity, and is regarded as the commanding height of global display technology. It is also regarded as a display technology revolution affecting the world. Revolutionary realization of full color gamut display, the most realistic reproduction of image color. Samsung, LG, Apple and other companies have stated that they are actively promoting the research and development of quantum dot display technology, while Amazon, Asus and other companies have also adopted quantum dot technology to improve the quality of their products. With the launch of TCL's first quantum dot television, the international quantum dot display camp has begun to take shape.

Quantum dots are made up of a limited number of atoms, all three dimensions are on the order of nanometers. Quantum dots are generally spherical or quasi-spherical, and are made of semiconductor materials (usually composed of II B ～ ⅥB or IIIB ～ VB elements) and have stable nanoparticles with a diameter of 2-20 nil2. Quantum dots are a collection of atoms and molecules on the nanometer scale, which can be composed of a semiconductor material, such as by II. Group VI elements (such as CdS, CdSe, CdTe, ZnSe, etc.) or III. Group V elements (such as InP, InAs, etc.) may also be composed of two or more semiconductor materials. As a novel semiconductor nanomaterial, quantum dots have many unique nano properties.

Due to the quantum confinement effect, the transport of electrons and holes inside it is restricted, so that the continuous band structure becomes a separate energy level structure. When the size of the quantum dots is different, the quantum confinement degree of electrons and holes is different, and the discrete energy level structures are different. After being excited by external energy, quantum dots of different sizes emit light of different wavelengths, that is, light of various colors.

The advantages of quantum dots are: by adjusting the size of the quantum dots, the emission wavelength range can cover the infrared and the entire visible light band, and the emission light band is narrow, and the color saturation is high; the quantum dot material has high quantum conversion efficiency; the material performance is stable; preparation The method is simple and diverse, and can be prepared from a solution with abundant resources.

However, after the light passes through the quantum dot, the emission direction is random. When the divergent light after passing through the quantum dot passes through the liquid crystal, it is no longer possible to control all the light at the corresponding pixel point, and the LCD will leak light. The LCD display device works by using the optical rotation and birefringence of the liquid crystal. The voltage is used to control the rotation of the liquid crystal, so that the linearly polarized light passing through the upper polarizer is rotated, and comes out from the lower polarizer (vertical to the upper polarizer). . Therefore, the polarizer and the liquid crystal cell function as an optical switch. Obviously, this kind of optical switch can not fully play the role of light emitted by quantum dots.

In order to avoid the phenomenon of light polarization cancellation when the quantum dots are placed in a liquid crystal cell, a solution has been previously proposed, that is, a quantum dot polarizer (QD POL) is provided, in which the quantum dots are placed in the polarizer. It is well known that a polarizer is a combination of multilayer films. One type of polarizers has improved backlight brightness utilization. Its basic structure includes: PVA (polyvinyl alcohol) in the middle, two layers of TAC (triacetate cellulose), PSA film (pressure-sensitive adhesive), and release film. Film) and Protective film, and other functional film structures. QD POL is to prepare quantum dots into a film and insert it between the polarizer functional layer positions. This layer not only improves the light energy utilization of the backlight, but also improves the color gamut of the panel, enhances the role of polarizers, and simplifies molding preparation Craft. However, there is a disadvantage in doing so. The light type emitted by the LCD backlight depends on the specific shape of the light source and the backlight structure. The brightness of different angles is different. For example, a typical Lambert type backlight, L (θ) = L (0 ) * cos (θ), the ratio of the brightness in the squint direction to the brightness in the front direction is the cosine of the included angle.

In general, the stimulated light emitted by quantum dots is non-polarized, which causes quantum dots to lose at least half their brightness after POL. When the quantum dots emit light with a certain degree of polarization, the light intensity transmitted through the polarizer can be greatly increased. The industry has researched this and found that quantum dot nanorods (QD When the rods are aligned, the light of the stimulated radiation has a certain polarization. In the existing research of quantum dot polarizers, quantum dot polarizers have been prepared using this property, but it is not clear how the nanorods are aligned when discotic liquid crystals are blended. The actual effect of disorderly arranged nanorods is similar to that of quantum dots, and it cannot achieve the effect of improving transmission. At the same time, the quantum dots are difficult to disperse in the discotic liquid crystal compensation layer.

technical problem

In the prior art, there are technical problems such as the loss of half of the brightness after the light passes through the quantum dot polarizer caused by the disorderly arrangement of the quantum dots, resulting in low light efficiency and waste of materials.

Technical solutions

The invention provides a quantum dot polarizer, comprising: a polarizing layer; and a compensation layer attached to one side of the polarizing layer. The compensation layer includes aligned quantum dot nanorods. Wherein, the side of the compensation layer remote from the polarizing layer is overprinted with two or more strip-shaped imprint structures, and the arrangement direction of the quantum dot nanorods is consistent with the strip-shaped direction of the imprint structure.

Further, the quantum dot polarizer further includes: a protective layer attached to a side of the polarizing layer away from the compensation layer; and a surface protective film attached to the protective layer away from the polarizing layer. The side.

Further, the quantum dot polarizer further includes: an adhesive layer attached to a side of the compensation layer away from the polarizing layer; and a peeling protective film attached to the adhesive layer away from the compensation layer. The side.

Further, in the quantum dot polarizer, the thickness of the adhesive layer is smaller than the height of the imprint structure, or the thickness of the adhesive layer is greater than or equal to the height of the imprint structure.

To achieve the above object, the present invention further provides a liquid crystal panel including the quantum dot polarizer.

To achieve the above object, the present invention further provides an electronic device including the liquid crystal panel.

To achieve the above object, the present invention also provides a method for preparing a quantum dot polarizer, including the following steps: S1 material preparation step, preparing a quantum dot nanorod material, the quantum dot nanorod material comprising a colloidal material and dispersed in Quantum dot nanorods in the colloidal material; S2 coating step, coating the quantum dot nanorod materials on one side of a polarizing layer to obtain a quantum dot layer; S3 pre-processing step, for the quantum dot layer Pre-processing is performed to obtain a semi-liquid and semi-solid quantum dot layer; S4 overprinting step, the semi-liquid and semi-solid quantum dot layer is mechanically overprinted; and S5 curing step is performed on the semi-liquid half The solid state quantum dot layer is cured to obtain a compensation layer, so that the quantum dot nanorods are aligned in the compensation layer, and the arrangement direction of the quantum dot nanorods is in the direction of the strip shape of the imprint structure. be consistent.

Further, in the overprinting step, the semi-liquid and semi-solid state quantum dot layer is mechanically overprinted by using a patterned roller or a brush.

Further, the method for preparing the quantum dot polarizer may further include the following steps: a S6 protective layer bonding step, a protective layer is bonded to a side of the polarizing layer away from the compensation layer; and S7 surface protection In the film bonding step, a surface protective film is bonded to a side of the protective layer away from the polarizing layer.

Further, the method for preparing the quantum dot polarizer may further include the following steps: an S8 adhesive layer attaching step, an adhesive layer is attached to a side of the compensation layer away from the polarizing layer; and S9 peeling protective film In the bonding step, a peeling protection film is bonded to a side of the adhesive layer away from the compensation layer.

Further, in the overprinting step, the semi-liquid and semi-solid state quantum dot layer is mechanically overprinted by using a patterned roller or a brush; and / or, in the adhesive layer bonding step, When the quantum dot layer in the semi-liquid and semi-solid state is not completely cured, the adhesive layer is adhered to the compensation layer.

Beneficial effect

The technical effect of the present invention is to provide a polarizer, in which the quantum dot nanorods in the compensation layer can be aligned, while ensuring the advantages of the quantum dot, it also has a strong polarization property, which greatly improves the efficiency of outgoing light; The arrangement direction of the quantum dot nanorods is consistent with the overprinting direction, so that when the polarizers are bonded, the transmission axis of the polarizer is guaranteed to be consistent with the overprinting direction, which greatly improves the optical efficiency of the optical quantum dot polarizer when paired with the liquid crystal display.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic cross-sectional structure diagram of a quantum dot polarizer according to an embodiment of the present invention;

2 is a flowchart of a method for manufacturing a quantum dot polarizer according to an embodiment of the present invention;

3 is a schematic structural diagram of the compensation layer before an overprinting step according to an embodiment of the present invention;

4 is a side view of the imprint structure according to the embodiment of the present invention;

FIG. 5 is a top view of a stamp structure according to an embodiment of the present invention; FIG.

6 is a schematic structural diagram of the compensation layer and the adhesive layer before the step of bonding the adhesive layer according to the embodiment of the present invention;

FIG. 7 is another schematic structural diagram of the compensation layer and the adhesive layer before the step of bonding the adhesive layer according to the embodiment of the present invention.

Some components are identified as follows:

1. Surface protective film;

2. Protective layer;

3. Polarizing layer;

4. Compensation layer; 41. Quantum dot nanorods; 42. Imprint structure;

5. Adhesive layer;

6. Peel off the protective film.

Best Mode of the Invention

The following describes the preferred embodiments of the present invention in detail with reference to the accompanying drawings in order to completely introduce the technical content of the present invention to those skilled in the art, to exemplify that the present invention can be implemented, to make the disclosed technical content of the present invention clearer, and to Those skilled in the art will more readily understand how to implement the invention. However, the present invention can be embodied in many different forms of embodiments. The protection scope of the present invention is not limited to the embodiments mentioned in the text, and the description of the following embodiments is not intended to limit the scope of the present invention.

The research on quantum dot polarizers in the prior art has been very common, mainly focusing on adding quantum dots to the adhesive layer, compensation layer or separate layered composite PVA of the polarizer. In the embodiment provided by the present invention, the quantum dots It is also within the scope of the present invention to add dots to the compensation layer, to the adhesive layer of the polarizer or to form a separate layer in accordance with PVA.

As shown in FIG. 1, this embodiment provides a quantum dot polarizer, which includes a surface protective film 1, a protective layer 2, a polarizing layer 3, a compensation layer 4, an adhesive layer 5, and a peeling protective film 6 in order from top to bottom. The material of the protective layer 2 includes cellulose triacetate (TAC), and the material of the polarizing layer 3 includes polyvinyl alcohol (PVA). The protective layer 2 is used to protect and support the polarizing layer 3. The material of the adhesive layer 5 includes a pressure-sensitive adhesive (PSA) and is used as an adhesive. The peeling protective film 6 is peeled off during the use of the quantum dot polarizer, and the adhesive layer 5 is attached to a substrate for use.

The compensation layer 4 contains quantum dot nanorods 41. The quantum dot nanorods 41 are dispersed in a photo-curable resin or a thermo-curable resin or a photo-thermo-curable resin, or are dispersed in a transparent thermo-curable colloid system (such as a pressure-sensitive adhesive). The mass percentage of the quantum dot nanorods 41 in the compensation layer 4 is less than 10%. The quantum dot nanorods 41 are aligned. The aligned quantum dot nanorods 41 have strong polarization, which can improve light transmittance and optical efficiency when matched with a liquid crystal display (LCD). Randomly arranged quantum dots The technical effects of nanorods and quantum dots are the same, and light transmission is poor.

As shown in FIG. 3, one or more elongated imprinted structures 42 are printed on one side of the compensation layer 4 away from the polarizing layer 3. The arrangement direction of the quantum dot nanorods 41 is consistent with the elongated direction of the imprinted structure 42. That is, the alignment direction of the quantum dot nanorods 41.

The thickness of the adhesive layer 5 is less than or equal to the height of the imprint structure 42. When the thickness of the adhesive layer 5 is smaller than the height of the imprint structure 42, an air layer exists between the imprint structure 42 and the adhesive layer 5, which facilitates the refraction of the optical path and converges in the central transmission direction, thereby improving optical efficiency. When the thickness is greater than or equal to the height of the imprint structure 42, the air layer gradually approaches 0, and the light emission direction is more divergent.

As shown in FIG. 2, this embodiment also provides a method for preparing a quantum dot polarizer, which specifically includes steps S1 to S9.

S1 Material preparation step, a quantum dot nanorod material is prepared. The quantum dot nanorod material includes a colloidal material and a quantum dot nanorod 41 dispersed in the colloidal material. The colloidal material includes a photo-curable resin or a thermal curing material. Resin or photothermosetting resin, or transparent thermosetting colloid system, such as pressure sensitive adhesive.

In the S2 coating step, the quantum dot nanorod material is coated on one side of a polarizing layer 4 to obtain a quantum dot layer.

In step S3, the quantum dot layer is pretreated to obtain a quantum dot layer in a semi-liquid and semi-solid state.

S4 Overprinting step, using a patterned roller or brush to mechanically overprint the semi-liquid and semi-solid quantum dot layer, so that two sides of the compensation layer 4 away from the polarizing layer 3 are overprinted. The above strip-shaped imprint structure 42.

In step S5, a curing process is performed on the semi-liquid and semi-solid quantum dot layer to obtain a compensation layer 4, so that the quantum dot nanorods 41 are aligned in the compensation layer 4. At this time, the main polarization direction of the stimulated emission light of the quantum dot nanorod 41 is also consistent with the strip direction of the imprint structure 42. During the bonding process of the polarizing layer 3 and the compensation layer 4, the transmission of the quantum dot polarizer The axis is also consistent with the elongated direction of the imprint structure 42, and finally the light transmittance can be greatly improved, and the optical efficiency can be further improved.

In step S6, the protective layer is laminated. A protective layer 2 is attached to a side of the polarizing layer 3 away from the compensation layer 4.

S7. The step of laminating the surface protective film, a surface protective film 1 is attached to a side of the protective layer 2 away from the polarizing layer 3.

In step S8 of bonding the adhesive layer, an adhesive layer 5 is applied to a side of the compensation layer 4 away from the polarizing layer 3, and the main material of the adhesive layer 5 is a pressure-sensitive adhesive.

As shown in FIG. 6, the adhesive layer 5 is bonded to the fully cured compensation layer 4, and the thickness of the adhesive layer 5 is smaller than the height of the imprint structure 42, so that an air layer exists between the imprint structure 42 and the adhesive layer 5, which is beneficial to The refraction of the optical path converges toward the central transmission direction, thereby improving the optical efficiency.

As shown in FIG. 7, the thickness of the adhesive layer 5 is greater than or equal to the height of the imprint structure 42. When the thickness of the adhesive layer 5 increases, the air layer gradually approaches 0, and the light emission direction is more divergent, which is beneficial to improve the light emission rate.

When the compensation layer 4 is not completely cured, the adhesive layer 5 can be attached to the compensation layer 4. At this time, the compensation layer 4 that has not been completely cured can be used to disperse the colloid of the quantum dot nanorod 41, so that the colloid is used as an adhesive at the same time, saving a process, saving man-hours, saving materials, and improving efficiency.

S9 Laminating protective film bonding step. A peeling protective film 6 is attached to the side of the adhesive layer 5 away from the compensation layer 4. After the peeling protective film 6 is peeled off, the adhesive layer 5 can be quickly and easily adhered to a substrate to be Used in subsequent processes.

In the above steps, steps S6 to S7 and steps S8 to S9 are two independent processes, and there is no order of execution.

As shown in FIGS. 4 and 5, the imprinted structure 42 of the quantum dot nanorods 41 in the compensation layer 4 has an elongated shape, and the arrangement direction of the quantum dot nanorods 41 in the compensation layer 4 is maintained with the elongated direction of the imprinted structure 42. It is consistent to ensure the alignment of the quantum dot nanorods 41.

Further, this embodiment may further provide a liquid crystal panel including the quantum dot polarizer. The quantum dot polarizer is a component of the liquid crystal panel and can be used as an upper polarizer or a lower polarizer. Since the quantum dots have light emitting characteristics and can increase the color gamut coverage, the quantum dot polarizer is more suitable for use as an upper polarizer of the liquid crystal panel.

Further, this embodiment may also provide an electronic device. The liquid crystal panel is a component of the electronic device. The electronic device may be used to display data such as text, pictures, and images, and may be used as an electronic device to communicate with users. Interface.

The technical effect of the present invention is to provide a quantum dot polarizer, in which the quantum dot nanorods are aligned in the compensation layer, while ensuring the advantages of the quantum dot, it also has a strong polarization property, which greatly improves the light emission efficiency. ; The arrangement direction of the quantum dot nanorods is consistent with the overprint direction, so that when the quantum dot polarizers are bonded, the transmission axis of the quantum dot polarizer is consistent with the overprint direction, which greatly improves the matching of the optical quantum dot polarizers with the liquid crystal display Optical efficiency.

The above is only a preferred embodiment of the present invention. It should be noted that, for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches can be made. These improvements and retouches should also be viewed as It is the protection scope of the present invention.

Claims

A quantum dot polarizer includes:

A polarizing layer; and

A compensation layer adhered to one side of the polarizing layer, the compensation layer comprising aligned quantum dot nanorods;

Wherein, the side of the compensation layer remote from the polarizing layer is overprinted with two or more strip-shaped imprint structures, and the arrangement direction of the quantum dot nanorods is consistent with the strip-shaped direction of the imprint structure.
The quantum dot polarizer according to claim 1, further comprising:

A protective layer attached to a side of the polarizing layer away from the compensation layer; and

A surface protective film is attached to a side of the protective layer away from the polarizing layer.
The quantum dot polarizer according to claim 1, further comprising:

An adhesive layer attached to a side of the compensation layer away from the polarizing layer; and

A peeling protective film is attached to a side of the adhesive layer away from the compensation layer.
The quantum dot polarizer of claim 3, further comprising:

The thickness of the adhesive layer is smaller than the height of the imprint structure, or

The thickness of the adhesive layer is greater than or equal to the height of the imprint structure.
A liquid crystal panel includes the quantum dot polarizer according to any one of claims 1-4.
An electronic device includes the liquid crystal panel according to claim 5.
A method for preparing a quantum dot polarizer includes the following steps:

S1 material preparation step, a quantum dot nanorod material is prepared, the quantum dot nanorod material comprises a colloidal material and quantum dot nanorods dispersed in the colloidal material;

S2 coating step, coating the quantum dot nanorod material on one side of a polarizing layer to obtain a quantum dot layer;

S3 a pre-processing step, pre-processing the quantum dot layer to obtain a quantum dot layer in a semi-liquid and semi-solid state;

S4 an imprinting step, performing mechanical imprinting processing on the semi-liquid and semi-solid state quantum dot layer; and

S5 curing step, curing the quantum dot layer in a semi-liquid and semi-solid state to obtain a compensation layer, so that the quantum dot nanorods are aligned in the compensation layer, and the quantum dot nanorods are aligned It is consistent with the strip-shaped direction of the imprint structure.
The method for preparing a quantum dot polarizer according to claim 7, further comprising the following steps:

S6: a protective layer bonding step, a protective layer is bonded to a side of the polarizing layer away from the compensation layer; and

In step S7, a surface protection film is attached, and a surface protection film is attached to a side of the protection layer away from the polarizing layer.
The method for preparing a quantum dot polarizer according to claim 7, further comprising the following steps:

S8: an adhesive layer attaching step, an adhesive layer is attached to a side of the compensation layer away from the polarizing layer; and

S9: A step of laminating the protective film, a peeling protective film is attached to a side of the adhesive layer away from the compensation layer.
The method for preparing a quantum dot polarizer according to claim 7, wherein:

In the printing step,

Mechanically imprinting the quantum dot layer in a semi-liquid and semi-solid state by using a patterned roller or a brush; and / or,

In the step of bonding the adhesive layer,

When the quantum dot layer in the semi-liquid and semi-solid state is not completely cured, the adhesive layer is bonded to the compensation layer.