# US 7,746,430 B2 · Reflective liquid crystal display device of lamination type wherein the difference in orientation regulating force results whether or not the orientation film is present

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- Number: US 7,746,430 B2
- Document ID: US7746430B2
- Status: Granted
- Kind: B2
- Application number: 11/964,429
- Filed: 2007-12-26
- Published: 2008-06-12
- Granted: 2010-06-29
- Earliest claimed: 2005-07-08
- Assignees: Fujitsu Limited
- Inventors: Yoshihisa Kurosaki; Toshiaki Yoshihara; Junji Tomita; Masaki Nose
- Web page: https://patentgrep.com/patent/US7746430B2

## CPC

- G02F 1/13718: {based on a change of the texture state of a cholesteric liquid crystal}
- G02F 1/13378: {by treatment of the surface, e.g. embossing, rubbing or light irradiation (G02F1/133711, G02F1/133734, G02F1/133753 take precedence)}
- G02F 1/1347: Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
- G02F 1/133773: {the alignment material or treatment being different for the two opposite substrates}
- G02F 1/13478: {based on selective reflection}
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

A high-contrast reflective liquid crystal display device of a lamination type in which scattering in the focal conic state of cholesteric liquid crystal has been reduced is described. The reflective liquid crystal display device has two or more laminated liquid crystal panels respectively having a liquid crystal layer of the cholesteric liquid crystal having different selective reflection wavelengths and the liquid crystal panel having a liquid crystal layer into which the liquid crystal having a longer selective reflection wavelength has been implanted has a smaller orientation regulating force of the liquid crystal layer applied to the panel.

## Claims

### Claim 1

A reflective liquid crystal display device of lamination type comprising:
two or more laminated liquid crystal panels respectively having a liquid crystal layer having different selective reflection wavelengths and exhibiting a cholesteric phase,
wherein the liquid crystal panel having a liquid crystal layer to which liquid crystal having a longer selective reflection wavelength has been implanted has a smaller orientation regulating force of the liquid crystal layer applied to the panel,
wherein each liquid crystal panel comprises the liquid crystal layer and two substrates that sandwich and hold the liquid crystal layer,
wherein at least one of the substrates of at least part of the liquid crystal panel comprises a transparent electrode formed on the surface and an orientation film formed on the transparent electrode, and
wherein the difference in the orientation regulating force results from whether or not the orientation film is present.

### Claim 2 (depends on 1)

The reflective liquid crystal display device of lamination type as set forth in claim 1,
wherein the liquid crystal layer of the liquid crystal panel arranged closer to the display surface side has a shorter selective reflection wavelength, and
wherein the liquid crystal panel arranged closer to the display surface side has a larger orientation regulating force of the liquid crystal layer applied to the panel.

### Claim 3 (depends on 1)

The reflective liquid crystal display device of lamination type as set forth in claim 1,
wherein the difference in the orientation regulating force results from whether or not the rubbing process has been performed on the orientation film and its density.

### Claim 4 (depends on 1)

The reflective liquid crystal display device of lamination type as set forth in claim 1,
wherein the orientation film is a light orientation film and the difference in the orientation regulating force results from whether or not the light orientation film has been irradiated with ultraviolet beams and its strength.

### Claim 5 (depends on 1)

The reflective liquid crystal display device of lamination type as set forth in claim 1,
wherein the substrate on the opposite side of the display surface of each liquid crystal panel comprises a lower transparent electrode formed on the surface and the orientation film formed on the lower transparent electrode, and
wherein the substrate on the display surface side of each liquid crystal panel comprises an upper transparent electrode formed on the surface but does not have an orientation film.

### Claim 6 (depends on 1)

The reflective liquid crystal display device of lamination type as set forth in claim 1,
wherein the rubbing process has been performed in a plurality of directions on the orientation film surface of the orientation film of at least part of the liquid crystal panel.

### Claim 7 (depends on 1)

The reflective liquid crystal display device of lamination type as set forth in claim 1,
wherein the substrate on the opposite side of the display surface of each liquid crystal panel comprises a lower transparent electrode formed on the surface and a light orientation film formed on the lower transparent electrode and a light orientation film formed on the lower transparent electrode, and
wherein the substrate on the display surface side of each liquid crystal panel comprises an upper transparent electrode formed on the surface but does not have an orientation film.

### Claim 8 (depends on 1)

The reflective liquid crystal display device of lamination type as set forth in claim 1,
wherein the ultraviolet beam irradiation process has been performed in a plurality of directions on the orientation film surface of the orientation film of at least part of the liquid crystal panel.