Bistable liquid crystal device with optical writing or optical erasing function and preparation method thereof

A bistable liquid crystal and optical writing technology, which is applied in the fields of instruments, optics, nonlinear optics, etc., can solve problems such as difficult control and complicated process, and achieve the effects of simple processing, simple synthesis, and large-area production

Active Publication Date: 2020-07-03
PEKING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Through a simple process, a cholesteric liquid crystal device that can smoothly switch between the planar texture and the focal conic texture under the condition of remote non-contact light radiation is prepared, which overcomes the complicated and difficult process. Controlled Orientation Technical Disadvantages

Method used

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  • Bistable liquid crystal device with optical writing or optical erasing function and preparation method thereof
  • Bistable liquid crystal device with optical writing or optical erasing function and preparation method thereof
  • Bistable liquid crystal device with optical writing or optical erasing function and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] Example 1: Electrical writing, optical erasing

[0049] The composite system of chiral helicene compound (right-handed) / R811 (right-handed) / nematic liquid crystal SLC1717 is blended according to the ratio of 1.00 / 5.30 / 93.70 to prepare a photoresponsive cholesteric liquid crystal composite system. Such as image 3 As shown, under excitation light (365nm, 10.0mW / cm 2 ) irradiation, the pitch of the photoresponsive cholesteric liquid crystal changes from p 0 = 1.1 μm becomes p 1 =7.8μm; when the excitation light is turned off, the pitch starts from p 1 = 7.8 μm reverts to p 0 = 1.1 μm. First, the liquid crystal composite system is poured into a liquid crystal cell with a cell thickness of 20 μm. The liquid crystal is in a planar texture, showing a transparent selective reflection state, and the visible light transmittance is about 95% ( Pic 4-1 ). Apply an electric field to the circular area where information needs to be written, and the arrangement of the liquid c...

Embodiment 2

[0052] Example 2: Electrical writing, optical erasing

[0053] Chiral helicene compound (left-handed) / S811(left-handed) / nanoparticle NaYF 4 : The compound system of Yb, Er / nematic liquid crystal E7 is blended according to the ratio of 1.60 / 4.80 / 0.90 / 92.70 to prepare a photoresponsive cholesteric liquid crystal compound system. Under excitation light (975nm, 200.0W / cm 2 ) irradiation, nanoparticles NaYF 4 :Yb,Er will emit ultraviolet light excited in situ, and the pitch of the photoresponsive cholesteric liquid crystal changes from p 0 =0.7μm becomes p 1 =3.7μm; when the excitation light is turned off, the pitch starts from p 1 = 3.7 μm reverts to p 0 = 0.7 μm. First, the liquid crystal composite system is poured into a liquid crystal cell with a cell thickness of 70 μm. The liquid crystal is in a plane texture, showing a transparent selective reflection state, and the visible light transmittance is about 94%. When an electric field is applied to the circular area where ...

Embodiment 3

[0056] Example 3: Optical writing, electrical erasing

[0057] The composite system of chiral helicene compound (right-handed) / R811 (right-handed) / nematic liquid crystal SLC1717 is blended according to the ratio of 1.40 / 5.10 / 93.50 to prepare a photoresponsive cholesteric liquid crystal composite system. Under excitation light (400nm, 30.0mW / cm 2 ) irradiation, the pitch of the photoresponsive cholesteric liquid crystal changes from p 0 = 1.0 μm becomes p 1 =9.4μm; when the excitation light is turned off, the pitch starts from p 1 = 9.4 μm reverts to p 0 = 1.0 μm. First, the liquid crystal composite system is poured into a liquid crystal cell with a cell thickness of 2 μm, and then an electric field is applied to the liquid crystal cell to make the arrangement of the liquid crystal molecules into a focal conic state, showing a light scattering state, and the transmittance is about 12% ( Figure 6-1 ). Then using excitation light (400nm, 30.0mW / cm 2 ) to irradiate the tri...

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Abstract

The invention discloses a bistable liquid crystal device with an optical writing or optical erasing function and a preparation method thereof. The bistable liquid crystal device comprises a liquid crystal box or liquid crystal film with the thickness of 2-200 micrometers, and a photoresponsive cholesteric liquid crystal composite system is poured into the liquid crystal box or the liquid crystal film; the photoresponsive cholesteric liquid crystal composite system is prepared from, by mass, 60.0 wt%-97.0 wt% of main micro-molecular liquid crystal materials, 0.5 wt%-15.0 wt% of chiral helicene compounds and 0.2 wt%-30.0 wt% chiral compounds; the initial pitch of the photoresponsive cholesteric liquid crystal composite system is p0, and the pitch rises to p1 or decreases to p2 under the irradiation of excitation light. Through a simple process, the cholesteric liquid crystal device capable of stably switching between a planar texture state and a focal conic texture state under the condition of remote non-contact illumination radiation is prepared.

Description

technical field [0001] The invention belongs to the field of bistable liquid crystal materials and devices. Specifically, the invention provides a bistable liquid crystal device with optical writing or optical erasing function and a preparation method thereof. The prepared liquid crystal device can be remotely and non-contact Under the light irradiation conditions of the formula, the planar texture and the focal conic texture of the cholesteric liquid crystal can be regulated and switched, and the characteristics of optical writing or optical erasing in different display modes can be achieved. The liquid crystal device can be widely used in the research of liquid crystal display, information storage, electronic tablet, smart glass, adjustable grating and related fields. Background technique [0002] Since liquid crystal was discovered in 1888, it has developed vigorously in the past 20 years. From the popular electronic watch to the current electronic paper, electronic book...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02F1/1333G02F1/137G02F1/139
CPCG02F1/1333G02F1/13718G02F1/1391
Inventor 杨槐孙健兰若尘张兰英
Owner PEKING UNIV
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