Display device including an optical modulator

Patent metadata

Field	Value
Publication number	US-9983437-B2
Application number	US-201615371569-A
Country	US
Kind code	B2
Filing date	Dec 7, 2016
Priority date	Dec 7, 2015
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

According to one embodiment, a display device includes a display panel including a display surface, which displays an image by selectively reflecting light entering the display surface, and an illuminating device including an optical modulator provided on a display surface side of the display panel and including a plurality of portions in a major surface thereof and a light source provided on a side surface of the optical modulator, and the illuminating device illuminates the display panel at a predetermined brightness specific for each respective portion with the light entering the optical modulator from the light source.

First claim

What is claimed is:

1. A display device comprising:
a display panel including a display surface, which displays an image by selectively reflecting light entering the display surface; and
an illuminating device comprising an optical modulator provided on a display surface side of the display panel and including a plurality of portions in a major surface thereof and a light source provided on a side surface of the optical modulator, the illuminating device illuminating the display panel at a predetermined brightness specific for each respective portion with the light entering the optical modulator from the light source,
the optical modulator comprising a first transparent substrate provided on a side close to the display panel; a second transparent substrate provided on a side away from the display panel; an optical modulation layer located between the first and second transparent substrates; and first and second electrodes applying an electric field to the optical modulation layer, and
the optical modulation layer exhibiting scattering property or transparency entirely or partially to the light from the light source according to an intensity and a direction of the electric field produced with the first and second electrodes.

2. The display device of claim 1 , wherein
at least one of the first and second electrodes includes partial electrodes located respectively in the plurality of portions.

3. The display device of claim 2 , wherein
the partial electrodes are arranged along a first direction, and
the light source comprises a plurality of dot-like light emitters arranged along a second direction intersecting the first direction.

4. The display device of claim 1 , wherein
the display panel comprises a polarizer provided on a side close to the illuminating device, and
the light scattered in the optical modulation layer is polarized in a direction parallel to a transmission axis of the polarizer.

5. The display device of claim 1 , wherein
the second electrode comprises a reflective layer located between the second transparent substrate and the optical modulation layer, and an optical absorption layer located between the second transparent substrate and the reflective layer, which absorbs visible light.

6. The display device of claim 1 , wherein
the optical modulation layer includes first and second region having optical anisotropy and different response speeds to an electric field,
the first region mainly contains a liquid crystal material, and
the second region mainly contains a polymeric material.

7. The display device of claim 6 , wherein
the display panel comprises a polarizer provided on a side close to the illuminating device,
the second region contains the polymeric material of a fibrous structure which has a longitudinal axis in a direction parallel to a transmission axis of the polarizer.

8. The display device of claim 6 , wherein
the first and second regions include respective optical axes which become parallel to each other when voltage is not applied to between the first and second electrodes.

9. The display device of claim 8 , wherein
the optical axis of the second region is parallel to a surface of the optical modulator, which the light from the light source enters.

10. The display device of claim 9 , wherein
the optical modulator includes horizontal alignment films between each of the first and second electrodes and the optical modulation layer, respectively.

11. The display device of claim 10 , wherein
the optical modulation layer has anisotropic scattering property in which scattering in a thickness direction of the optical modulation layer, which is perpendicular to the major surface thereof, is greater than scattering in a direction parallel to the major surface of the optical modulation layer.

12. The display device of claim 6 , wherein
the first and second regions have ordinary light refractive indexes equal to each other and extraordinary light refractive indexes equal to each other.

13. The display device of claim 6 , wherein
the optical modulation layer further includes a third region formed of a resin material having an optical transmittance higher than that of the first or second region.

14. A display device comprising:
a display panel including a display surface, which displays an image by selectively reflecting light entering the display surface; and
an illuminating device comprising an optical modulator provided on a display surface side of the display panel and a light source provided on a side surface of the optical modulator, the illuminating device illuminating the display panel with the light entering the optical modulator from the light source,
the optical modulator further comprising:
a first transparent substrate provided on a side close to the display panel;
a second transparent substrate provided on a side away from the display panel;
an optical modulation layer located between the first and second transparent substrates; and
first and second electrodes which apply an electric field to the optical modulation layer, and
the optical modulation layer exhibiting scattering property or transparency entirely or partially to the light from the light source according to an intensity and a direction of the electric field produced with the first and second electrodes.

15. The display device of claim 14 , wherein
the second electrode comprises a reflective layer located between the second transparent substrate and the optical modulation layer, and an optical absorption layer located between the second transparent substrate and the reflective layer, which absorbs visible light.

16. The display device of claim 14 , wherein
the optical modulation layer includes first and second region having optical anisotropy and different response speeds to an electric field,
the first region mainly contains a liquid crystal material, and
the second region mainly contains a polymeric material.

17. The display device of claim 16 , wherein
the display panel comprises a polarizer provided on a side close to the illuminating device,
the second region contains the polymeric material of a fibrous structure which has a longitudinal axis in a direction parallel to a transmission axis of the polarizer.

18. The display device of claim 16 , wherein
the first and second regions include respective optical axes which become parallel to each other when voltage is not applied to between the first and second electrodes.

19. The display device of claim 18 , wherein
the optical axis of the second region is parallel to a surface of the optical modulator, which the light from the light source enters.

20. The display device of claim 19 , wherein
the optical modulator includes horizontal alignment films between each of the first and second electrodes and the optical modulation layer, respectively.

21. The display device of claim 20 , wherein
the optical modulation layer has anisotropic scattering property in which scattering in a thickness direction of the optical modulation layer, which is perpendicular to the major surface thereof, is greater than scattering in a direction parallel to the major surface of the optical modulation layer.

22. The display device of claim 16 , wherein
the first and second regions have ordinary light refractive indexes equal to each other and extraordinary light refractive indexes equal to each other.

23. The display device of claim 16 , wherein
the optical modulation l

Assignees

• Japan Display Inc

Inventors

• Okuyama Kentaro

Classifications

• G02F1/137

  characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering · CPC title

• G02F1/133553

  Reflecting elements (associated to illuminating devices G02F1/133605) · CPC title

• G02F1/1337

  Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers · CPC title

• G02F1/134309

  characterised by their geometrical arrangement · CPC title

• G02F1/1334 Primary

  based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals · CPC title