CN-122012119-A - Cholesterol type liquid crystal composition, reflective liquid crystal display panel, preparation method of reflective liquid crystal display panel and reflective liquid crystal display device

CN122012119ACN 122012119 ACN122012119 ACN 122012119ACN-122012119-A

Abstract

The application relates to the technical field of liquid crystal display devices, in particular to a cholesterol type liquid crystal composition, a reflective liquid crystal display panel, a preparation method of the reflective liquid crystal display panel and a reflective liquid crystal display device. The raw material components of the cholesteric liquid crystal composition comprise nematic liquid crystal, a first chiral compound and a second chiral compound, the optical rotation of the first chiral compound and the optical rotation of the second chiral compound are opposite, and the surface tension of the first chiral compound is smaller than the surface tension of the second chiral compound. The structure effect similar to the function of double-layer left-right-handed cholesterol liquid crystal is achieved, the limitation that the theoretical reflectivity of the traditional single-rotation cholesterol liquid crystal is not more than 50% is overcome, and the overall reflectivity and the display brightness are improved. Because the two chiral components with different optical rotation are vertically layered in the same liquid crystal continuous phase, and an independent double-layer structure is formed by external lamination, no obvious independent mechanical interface exists between the layers, the light scattering loss can be reduced, and the optical coupling efficiency is improved.

Inventors

BI JINGZE
LI MINGXU
DONG JUNJIE
XIA JUNWEI
ZHENG LIBIN
LIN XIQIAN
LI JIEWEI

Assignees

惠科股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260409

Claims (12)

1. A cholesteric liquid crystal composition characterized in that a raw material component of the cholesteric liquid crystal composition comprises a nematic liquid crystal, a first chiral compound and a second chiral compound, the optical rotations of the first chiral compound and the second chiral compound are opposite, and the surface tension of the first chiral compound is smaller than the surface tension of the second chiral compound.
2. The cholesteric liquid crystal composition of claim 1 wherein the first chiral compound has a surface tension of less than 30mN/m and the second chiral compound has a surface tension of greater than 30mN/m.
3. The cholesteric liquid crystal composition according to claim 1, wherein the first chiral compound is selected from the group consisting of perfluoroalkyl-containing modifications R811, perfluoroalkyl-containing modifications S811, perfluoroalkyl-containing modifications R1011, perfluoroalkyl-containing modifications S1011, perfluoroalkyl-containing modifications CB15 (R), and perfluoroalkyl-containing modifications CB15 (S).
4. The cholesteric liquid crystal composition of claim 1, wherein the second chiral compound is selected from the group consisting of R811, S811, ZLI811, R811-OH, S811-OH, R1011-OH, and S1011-OH.
5. The cholesteric liquid crystal composition of any one of claims 1-4, wherein the starting components of the cholesteric liquid crystal composition further comprise a low surface tension aid.
6. The cholesteric liquid crystal composition of claim 5, wherein the low surface tension aid is a fluorochemical, a silane compound, or a siloxane compound.
7. The cholesteric liquid crystal composition of claim 6, wherein the fluorine-containing compound comprises perfluorohexyl ethyl acrylate, perfluoropolyether diacrylate, or fluorine-modified polysiloxane, the silane compound comprises methyltrimethoxysilane oligomer, and the siloxane compound comprises hydroxy-terminated polydimethylsiloxane or fluorine-modified polysiloxane.
8. The cholesteric liquid crystal composition of claim 5, wherein the raw material components of the cholesteric liquid crystal composition further comprise a photoinitiator and a polymerization monomer, the photoinitiator being configured to initiate polymerization of the polymerization monomer upon exposure to light.
9. The cholesteric liquid crystal composition of claim 8, wherein the photoinitiator is selected from the group consisting of TPO, DMAP, photoinitiator 907, and photoinitiator 184, and the polymerized monomer is selected from the group consisting of 2-EHA, TMPTA, PEGMEA and HEMA.
10. A reflective liquid crystal display panel, comprising: A first substrate; The second substrate is arranged on one side of the first substrate; A liquid crystal layer disposed between the first substrate and the second substrate, the liquid crystal layer comprising a liquid crystal film made of the cholesteric liquid crystal composition of any one of claims 1 to 9.
11. A method for manufacturing a reflective liquid crystal display panel according to claim 10, comprising: Providing a first substrate and a second substrate respectively, and forming a rubber frame on the second substrate; Mixing the raw material components of the cholesterol type liquid crystal composition to obtain a uniform and stable liquid crystal composition mixed system; Coating the liquid crystal composition mixed solution on the surface of a second substrate to form a liquid crystal film structure; after the layered structure of the liquid crystal film is stable, the first substrate is covered on the second substrate, so that the first substrate and the second substrate are connected through the rubber frame.
12. A reflective liquid crystal display device comprising the reflective liquid crystal display panel of claim 10.

Description

Cholesterol type liquid crystal composition, reflective liquid crystal display panel, preparation method of reflective liquid crystal display panel and reflective liquid crystal display device Technical Field The application relates to the technical field of liquid crystal display devices, in particular to a cholesterol type liquid crystal composition, a reflective liquid crystal display panel, a preparation method of the reflective liquid crystal display panel and a reflective liquid crystal display device. Background Although the conventional display panel (such as a liquid crystal display panel) has the characteristics of light weight, durability, energy saving, environmental protection and low power consumption, the backlight source is required to be matched for use, so that the overall thickness of the module is increased, and the production and application costs are increased. In this context, electronic paper reflective displays are new display schemes that meet the needs of the public. The display can realize image display by means of external natural or environmental light sources without relying on backlight sources like a liquid crystal display, so that a user can clearly read information on electronic paper even in a scene with strong outdoor sunlight, and the problem of limited viewing angle does not exist. The current mainstream electronic paper display technology routes are various, and common technologies include an E-Ink microcapsule technology (microcapsule electronic Ink technology), a SiPix microcup technology (microcup type electrophoretic display technology), a Bridgestone electronic liquid powder technology, a cholesterol type liquid crystal display technology (Cholesteric Liquid CRYSTAL DISPLAY, abbreviated as CLCD) and an electrowetting (Electrowetting) technology. Among these, the cholesteric liquid crystal display technology has a core advantage in that its bistable property is embodied in two stable states of a planar state and a focal conic state, because the cholesteric liquid crystal therein has a specific pitch, and when the pitch is close to the wavelength of incident light, a specific optical rotation in a specific wavelength can be selectively reflected. When a voltage is applied thereto, the alignment state of the cholesteric liquid crystal molecules can be regulated so that it switches between these two stable states. In contrast, when the cholesteric liquid crystal is in a focal conic state, the light can directly penetrate. Based on this characteristic, the cholesteric liquid crystal can be controlled to take a state of "allowing light to pass through" or "reflecting light of a specific wavelength" by applying a voltage thereto. This process allows the display content to be maintained without the need for continuous power, greatly reducing power consumption. The characteristics enable the electronic book to be widely applied to the product fields of electronic books, electronic papers, electronic whiteboards, outdoor billboards and the like which have requirements on low power consumption. However, the existing single-color cholesterol type liquid crystal display technology has a core bottleneck which is difficult to break through. The traditional single-layer structure is limited by the principle of single-rotation reflection of the liquid crystal layer, and the theoretical reflectivity cannot break through 50%, so that the display brightness is insufficient, and the visibility under outdoor strong light is poor. In the related art, there are two-layer structure schemes attempting to break the reflectivity limit, namely, a physical stacking process is generally adopted to prepare a left-handed liquid crystal layer and a right-handed liquid crystal layer respectively, and then physical lamination or secondary coating is carried out, so that the step-by-step manufacturing process has the remarkable defects that on one hand, the production cost and time are increased by two independent coating or printing procedures, the yield is reduced, on the other hand, the two-layer liquid crystal layer structure lacks sufficient mechanical support, interlayer slippage or uneven thickness is easy to occur when external pressure or bending is carried out, so that color spots and performance decline are displayed, and on the other hand, physical spacing layers or air are inevitably present among materials of the multi-layer liquid crystal layer, so that the reflectivity improvement is limited. Disclosure of Invention The application aims to solve the technical problems that the single-layer structure cholesterol type liquid crystal layer has insufficient reflectivity, and the cholesterol type liquid crystal layer adopting the double-layer physical lamination structure has complex process, high cost and poor mechanical stability, and the reflectivity is limited to be improved due to the existence of a physical spacing layer or air between layers. In order to solve the technical problem