Optical member and image display device including optical member

Patent metadata

Field	Value
Publication number	US-10222525-B2
Application number	US-201715496622-A
Country	US
Kind code	B2
Filing date	Apr 25, 2017
Priority date	Oct 31, 2014
Publication date	Mar 5, 2019
Grant date	Mar 5, 2019

Abstract

The optical member of the present invention includes: a substrate; and a dot that is in contact with a surface of the substrate, in which the dot has wavelength selective reflecting properties, the dot is formed of a liquid crystal material having a cholesteric structure, the cholesteric structure has a stripe pattern including bright portions and dark portions in a cross-sectional view of the dot when observed with a scanning electron microscope, the dot includes a portion having a height which continuously increases to a maximum height in a direction moving from an end portion of the dot to the center of the dot, in the portion, an angle between a normal line perpendicular to a line, which is firmed using a first dark portion from a surface of the dot, and the surface is in a range of 70° to 90°, and the liquid crystal material includes a surfactant.

First claim

What is claimed is:

1. An optical member comprising:
a substrate; and
a dot that is in contact with a surface of the substrate,
wherein the dot has wavelength selective reflecting properties,
the dot is formed of a liquid crystal material having a cholesteric structure,
the cholesteric structure has a stripe pattern including bright portions and dark portions in a cross-sectional view of the dot when observed with a scanning electron microscope,
the dot includes a portion having a height which continuously increases to a maximum height in a direction moving from an end portion of the dot to the center of the dot,
regarding all the points of an inclined portion or a curved portion from said end portion of the dot, an angle between a normal line perpendicular to a line, which is formed using a first dark portion from a surface of the dot, and the surface of the dot is in a range of 70° to 90°, and
the liquid crystal material includes a surfactant.

2. The optical member according to claim 1 ,
wherein a plurality of the dots are provided in a pattern shape on the surface of the substrate.

3. The optical member according to claim 1 ,
wherein a diameter of the dot is 20 to 200 μm.

4. The optical member according to claim 1 ,
wherein a diameter of the dot is 30 to 120 μm.

5. The optical member according to claim 1 ,
wherein a value obtained by dividing the maximum height by the diameter of the dot is 0.13 to 0.30.

6. The optical member according to claim 1 ,
wherein in the end portion of the dot, an angle between the surface of the dot and the substrate is 27° to 62°.

7. The optical member according to claim 1 ,
wherein the surfactant is a fluorine surfactant.

8. The optical member according to claim 1 ,
wherein the liquid crystal material is a material obtained by curing a liquid crystal composition including a liquid crystal compound, a chiral agent, and the surfactant.

9. The optical member according to claim 1 ,
wherein the dot has wavelength selective reflecting properties in which a center wavelength is present in an infrared range.

10. The optical member according to claim 9 ,
wherein the dot has wavelength selective reflecting properties in which a center wavelength is present at a wavelength of 800 to 950 nm.

11. The optical member according to claim 1 which is transparent in a visible range.

12. An image display device comprising the optical member according to claim 11 .

13. The optical member according to claim 7 ,
wherein the surfactant comprises a compound represented by the following Formula (I):
(Hb 11 -Sp 11 -L 11 -Sp 12 -L 12 ) m11 -A 11 -L 13 -T 11 -L 14 -A 12 -(L 15 -Sp 13 -L 16 -Sp 14 -Hb 11 ) n11   Formula (I)

wherein L 11 , L 12 , L 13 , L 14 , L 15 , and L 16 each independently represent a single bond, —O—, —S—, —CO—, —COO—, —OCO—, —COS—, —SCO—, —NRCO—, or —CONR— (in Formula (I), R represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms),
Sp 11 , Sp 12 , Sp 13 , and Sp 14 each independently represent a single bond or an alkylene group having 1 to 10 carbon atoms,
A 11 and A 12 represent a monovalent to tetravalent aromatic hydrocarbon group, T 11 represents a divalent group or a divalent aromatic heterocyclic group represented by any one of the following formulae (X in T 11 represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group, a halogen atom, a cyano group, or an ester group, Ya, Yb, Yc, and Yd each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and
o and p each independently represent an integer of 0 to 4),

Hb 11 represents a perfluoroalkyl group having 2 to 30 carbon atoms,
m11 and n11 each independently represent 0 to 3 and m11+n11≥1.

14. The optical member according to claim 7 ,
wherein Hb 11 -Sp 11 -L 11 -Sp 12 -L 12 and -L 15 -Sp 13 -L 16 -Sp 14 -Hb 11 present at the terminal of Formula (I) are a group represented by any one of the following formulae:
(C a F 2a+1 )—(C b H 2b )—O—;

(C a F 2a+1 )—(C b H 2b )—COO—;

(C a F 2a+1 )—(C b H 2b )—O—(C r H 2r )—O—;

(C a F 2a+1 )—(C b H 2b )—COO—(C r H 2r )—COO—; and

(C a F 2a+1 )—(C b H 2b )—OCO—(C r H 2r )—COO—,

wherein a represents an integer of 2 to 30, b represents an integer of 0 to 20, a+b represents 3 to 30, and r represents an integer of 1 to 10.

15. The optical member according to claim 7 ,
wherein the surfactant comprises the following compound

16. The optical member according to claim 8 ,
wherein the addition amount of the surfactant in the liquid crystal composition is 0.01 mass % to 10 mass %.

17. The optical member according to claim 15 ,
wherein the liquid crystal material is a material obtained by curing a liquid crystal composition including a liquid crystal compound, a chiral agent, and the surfactant.

18. The optical member according to claim 17 ,
wherein the addition amount of the surfactant in the liquid crystal composition is 0.01 mass % to 10 mass %.

19. The optical member according to claim 8 ,
wherein the liquid crystal compound is a combination of the following compounds:

20. The optical member according to claim 19 ,
wherein the surfactant comprises the following compound:

Assignees

• Fujifilm Corp

Inventors

• Nagai Michio
• Ito Yoji
• Kashiwagi Daisuke
• Yamamoto Akira
• Ichihara Nobuhiko
• Nakamura Hideyuki

Classifications

• G02B5/26 Primary

  Reflecting filters (G02B5/28 takes precedence) · CPC title

• G06F3/0321

  by optically sensing the absolute position with respect to a regularly patterned surface forming a passive digitiser, e.g. pen optically detecting position indicative tags printed on a paper sheet (constructional details of pen-shaped pointing devices G06F3/03545, G06F3/03542, G06F3/037) · CPC title

• G06F3/0421

  by interrupting or reflecting a light beam, e.g. optical touch-screen · CPC title

• G06F3/03545

  Pens or stylus · CPC title