Liquid crystalline film

• US 6,627,270 B1
• Filed: 10/23/2000
• Issued: 09/30/2003
• Est. Priority Date: 04/23/1998
• Status: Expired due to Term

• Current Assignee: Nippon Mitsubishi Oil Corporation (ENEOS Holdings, Inc.)
• Original Assignee: Nippon Mitsubishi Oil Corporation (ENEOS Holdings, Inc.)
• Inventors: Nishimura, Suzushi
• Primary Examiner(s): WU, SHEAN CHIU
• Application Number:
  US09/673,902
• Time in Patent Office: 1,072 Days
• Field of Search: 428/1.1, 428/1.2, 428/1.3, 252/299.01, 349/201
• US Class Current: 428/1.3
• CPC Class Codes: B42D 25/355 Security threads
• CPC Class Codes: B42D 25/364 Liquid crystals
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
• CPC Class Codes: C09K 2323/03 Viewing layer characterised by chemical composition
• CPC Class Codes: G02B 5/3016 involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528
• CPC Class Codes: G02F 1/1335 Structural association of cells with optical devices, e.g. polarisers or reflectors

Abstract

A liquid crystalline film which functions suitably as a polarization rotating lattice is provided. The liquid crystalline film is characterized in that a cholesteric orientation or a chiral smectic C orientation, in which helical axis is not uniformly parallel in the thickness direction of the film nor is helix pitch of helices uniformly equal in the film thickness direction, is formed in a certain region of the film.

Claims

1. A liquid crystalline film in which a cholesteric orientation or a chiral smectic C orientation, in which the helical axis is not uniformly parallel in the film thickness direction nor is the helix pitch uniformly equal in the film thickness direction, is formed in a certain region of the film.

2. The liquid crystalline film of claim 1, wherein said cholesteric orientation or chiral smectic C orientation is formed in a surface region of the film and/or an interior region of the film.

3. A process for fabricating the liquid crystalline film described in claim 1, wherein a diffraction pattern is transferred to a liquid crystal layer to obtain the liquid crystalline film.

4. The process of claim 3, wherein the liquid crystal layer is a liquid crystalline polymer layer.

5. The process of claim 4, wherein the diffraction pattern is transferred to said liquid crystalline polymer layer in a temperature range of above a glass transition point of the liquid crystal and below an isotropic phase transition temperature of the liquid crystal and in a pressure range of 0.3 to 500 kgf/cm².

6. An optical element characterized in that the liquid crystalline film described in claim 1 is laminated to an optical member through an adhesive free of any difference in refractive index.

7. An optical element obtained by transferring a diffraction pattern to a surface of a liquid crystal layer in the liquid crystalline film described in claim 1 to make said surface uneven in accordance with the diffraction pattern and by subsequently leveling the uneven surface with use of an adhesive free of any difference in refractive index.