REFLECTION TYPE DISPLAY APPARATUS

• US 20090021822A1
• Filed: 07/07/2008
• Published: 01/22/2009
• Est. Priority Date: 07/18/2007
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Ikeda, Hajime
• Granted Patent: US 7,889,414 B2
• Time in Patent Office: Days
• US Class Current: 359/267
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: 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
• CPC Class Codes: G02F 1/153 Constructional details

Abstract

An object of the present invention is to provide a reflection type display apparatus that has reduced unwanted reflection when black is displayed, has a high reflectance when white is displayed and can provide color display. For that object, a reflection type display apparatus according to the present invention includes: a first light modulating layer 101 for controlling electrically and externally a light absorbing state and a light transmitting state; a second light modulating layer 102 for controlling electrically and externally a light reflecting state and the light transmitting state; and a reflector 9 for reflecting light in a particular wavelength band, wherein the first light modulating layer 101, the second light modulating layer 102 and the reflector 9 are arranged in this order from a light incidence side.

Claims

1. A reflection type display apparatus comprising:

a first light modulating layer for controlling electrically and externally a light absorbing state and a light transmitting state;

a second light modulating layer for controlling electrically and externally a light reflecting state and the light transmitting state;

a reflector for reflecting light of a particular wavelength band, wherein

the first and second light modulating layers and the reflector are arranged in this order from a light incidence side.

2. The reflection type display apparatus according to claim 1, wherein an absorption ratio A₁ of the first light modulating layer, and a reflection ratio R₂ of the second light modulating layer are controlled such that, under a condition that an intensity of an incident light is normalized as being 1 and a reflection ratio of the reflector is set as being R_c, an intensity I of a reflected light meets a relation:

I=(1−

A₁)²·

R₂+(1−

A₁)²·

(1−

R₂)²·

R_c.

3. The reflection type display apparatus according to claim 1, comprises a plurality of pixels arranged in a matrix, wherein each of the pixels comprises the first and second light modulating layers and the reflector.

4. The reflection type display apparatus according to claim 1, further comprising

a light scattering layer arranged nearer to the light incidence side rather than the second light modulating layer.

5. The reflection type display apparatus according to claim 1, wherein

the reflector comprises a first reflector for reflecting a red light, a second reflector for reflecting a green light and a third reflector for reflecting a blue light.

6. The reflection type display apparatus according to claim 1, wherein

the reflector comprises a multilayered dielectric film for reflecting light of the particular wavelength band.

7. The reflection type display apparatus according to claim 1, wherein

the reflector comprises a paper colored in a particular color.

8. The reflection type display apparatus according to claim 1, wherein

the first light modulating layer comprises a first electrode of a light transmitting property arranged at the light incidence side, and a first counter electrode disposed in opposition to the first electrode sandwiching a first electrolytic solution containing a first metal ion between the first electrode and the first counter electrode, for controlling the light absorbing state and the light transmitting state according to depositing of the first metal ion onto the first electrode and according to dissolving of the first metal ion into the first electrolytic solution, and

the second light modulating layer comprises a second electrode of a light transmitting property arranged at the light incidence side, and a second counter electrode disposed in opposition to the second electrode sandwiching a second electrolytic solution containing a second metal ion between the second electrode and the second counter electrode, for controlling the light reflection state and the light transmitting state according to depositing of the second metal ion onto the second electrode and according to dissolving of the second metal ion into the second electrolytic solution.

9. The reflection type display apparatus according to claim 8, wherein

the second electrode of the second light modulating layer has concave and convex shape for scattering light.