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A method for controlling the orientation of cholesteric liquid crystal gratings

A cholesteric liquid crystal, photo-alignment technology, applied in optics, nonlinear optics, instruments, etc., can solve the problems of dust pollution, scratches, product yield decline, etc., to expand applications, increase flexibility and diversification. Effect

Active Publication Date: 2018-09-21
XIAMEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The rubbing alignment method can provide a strong alignment ability of liquid crystal molecules, but during the rubbing process, due to the contact friction of the flannelette, static electricity, scratches, and dust pollution will be generated, and these pollutions often directly cause damage to the liquid crystal elements, resulting in Product yield drops

Method used

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  • A method for controlling the orientation of cholesteric liquid crystal gratings
  • A method for controlling the orientation of cholesteric liquid crystal gratings
  • A method for controlling the orientation of cholesteric liquid crystal gratings

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] This embodiment realizes the optical alignment of liquid crystals by surface dielectric light induction and proximity mask method.

[0052] Cut an ITO glass with a size of 25mm×20mm, and ultrasonically clean it with a mixed solution of ITO cleaning agent and deionized water (3:97) for 40 minutes, and then ultrasonically clean it with absolute ethanol for 20 minutes. After 30 minutes in an oven at 120 °C, UVO cleaning was performed for 30 minutes to increase wettability and adhesion. The organic solvent DMF (N, N-Dimethylformamide, N, N dimethylformamide) solution is spin-coated on the surface of the ITO glass conductive layer, wherein the DMF solution is doped with an azo photo-alignment material SD1 (molecular formula such as image 3 shown). Spin-coating parameters are as follows: low-speed spin-coating for 5 seconds with a rotation speed of 800 n / min, high-speed spin-coating for 40 seconds with a rotation speed of 3000 n / min. After finishing, put it in the oven and...

Embodiment 2

[0057] As in Example 1, the ITO glass of the same size was cut, and after cleaning and drying, the DMF solution doped with SD2 was spin-coated on the ITO glass conductive layer. Put it in the oven again and dry it at 120°C. then. Spray evenly space powder with a diameter of 5 μm on one of the glass sheets, and then glue the two glass sheets to form a liquid crystal cell.

[0058] Put the cholesteric liquid crystal (the mixture of 5CB and R811, the ratio is 98:2) and the liquid crystal box into the oven and heat to 40°C (clearing point 36°C), and pour the liquid crystal. After the liquid crystal is full of the liquid crystal box, close the heating box and let it cool down naturally.

[0059] Place the filled liquid crystal cell as Figure 8 on the optical path. The laser 7 (405nm) emits laser light and passes through the polarizer 8 to become linearly polarized light. The beam expander and collimator mirror 9 expands the laser beam and enters the dynamic mask system 15 (whi...

Embodiment 3

[0062] This embodiment realizes liquid crystal grating orientation for surface medium light orientation and projection method

[0063] Same as Example 1, after cleaning and drying the ITO glass, spin coating doped with SDA1 (azo dye monomer, molecular formula such as Figure 9 Shown) and the DMF solution of initiator V-65. After spin coating, two pieces of ITO glass 10 were placed on the Figure 4 In the light path, the initial exposure (exposure dose is 5J / cm 2 ). Then place the ITO glass 10 on such as Figure 10 In the light path, carry out re-exposure (exposure dose is 5J / cm 2 ). Figure 10 and Figure 6 The difference is in Figure 6 A condensing lens group 18 and a projection objective lens group 20 are added before and after the template 11 to form a projection lithography system 21 .

[0064] After the exposure, the two glass slides were placed in an oven at 150°C for 1 hour to allow thermal polymerization of SDA1 and remove excess components.

[0065] Same as ...

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Abstract

The invention discloses a method of controlling the orientation of a cholesteric liquid crystal raster. The method comprises the following steps: (1) coating photo-alignment materials on the surfaces of conductive layers of conductive substrates; (2) illuminating the surfaces, coated with the photo-alignment materials, of the conductive layers of the conductive substrates through a mask system by linear polarized light, so as to expose; (3) repeating the step (2) for multiple times in different areas of the conductive substrates after different polarization angles are rotated; (4) heating a liquid crystal box made by two exposed conductive substrates in an alignment way to above a clearing point, and then filling a mixture of a nematic phase liquid crystal, a chiral material, a polymeric monomer and an initiator which are heated to above the clearing point, and naturally cooling to enable liquid crystal molecules to re-orientate; (5) adding AC (Alternating Current) voltage to the cooled liquid crystal box to form the raster. According to the method provided by the invention, the control and preparation of any graph and any direction of orientation can be realized without mechanical alignment, and the flexibility and diversity of the production of the liquid crystal raster can be greatly improved.

Description

technical field [0001] The invention belongs to the technical field of liquid crystal gratings, and in particular relates to a method for controlling the orientation of cholesteric liquid crystal gratings. Background technique [0002] In the research or application of liquid crystals, how to arrange the liquid crystal molecules in an orderly manner is a very important key step, which is generally called liquid crystal alignment. The most common liquid crystal alignment method is to form a film formed by coating the alignment material on the surface of the substrate, and then use friction to make the long-bond molecules of the alignment film produce a directional arrangement. The force produces an ordered arrangement of liquid crystal molecules. Finally, the effect of liquid crystal alignment is achieved. The rubbing alignment method can provide a strong alignment ability of liquid crystal molecules, but during the rubbing process, due to the contact friction of the flanne...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02F1/1337
CPCG02F1/1337G02F1/133788G02F1/133796
Inventor 陈鹭剑李森森罗斌李文松杨璨
Owner XIAMEN UNIV