Liquid crystal display cell having a diffusely-reflective counter electrode

• US 4,904,060 A
• Filed: 11/22/1988
• Issued: 02/27/1990
• Est. Priority Date: 11/23/1987
• Status: Expired due to Fees

• Current Assignee: Asulab SA A Swiss Ccorp
• Original Assignee: Asulab SA (The Swatch Group AG)
• Inventors: Grupp, Joachim
• Primary Examiner(s): Miller, Stanley D.
• Assistant Examiner(s): Gallivan, Richard
• Application Number:
  US07/274,551
• Time in Patent Office: 462 Days
• Field of Search: 350/336, 350/338, 350/339 D
• US Class Current: 349/162
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 2201/121 common or background
• CPC Class Codes: G02F 2203/02 reflective

Abstract

In a reflector-diffuser type liquid crystal display cell, the control electrodes, which are transparent, electronic components and tracks connecting the components to the cell terminals are disposed between the cell front plate and the liquid crystal layer. The counter electrode is disposed on the other side of the liquid crystal layer and has a frosted rough light reflecting and diffusing face over its entire surface situated in the display area and thus itself functions as the cell reflector-diffuser.

Claims

1. A liquid crystal display cell of the type having a reflector-diffuser and at most one polarizer, comprising

a first transparent plate,

a second plate,

a liquid crystal layer disposed between said first and second plates,

a plurality of transparent control electrodes disposed between said first transparent plate and said liquid crystal layer in a display area,

a plurality of electronic components connected each to one of said control electrodes, and

a counter electrode situated between said second plate and said liquid crystal layer, said counter electrode being of light-reflecting material and having irregularities over its entire surface situated in said display area so as to reflect and diffuse impinging light, whereby said counter electrode is also said reflector-diffuser.

2. A display cell according to claim 1, wherein said counter electrode contacts the face of said second plate oriented towards said liquid crystal layer.

3. A display cell according to claim 2, wherein said face of the second plate oriented towards the liquid crystal layer is frosted over its entire surface and said counter electrode presents substantially the same irregularities as said frosted face of said second plate.

4. A display cell according to claim 2, wherein the face of said counter electrode located adjacent to said liquid crystal layer is frosted over its entire surface situated in said display area.

5. A display cell according to claim 3, wherein said first plate is disposed in front of said cell, said control electrodes are disposed on said first plate, and said electronic components are disposed on said first plate between the latter and said liquid crystal layer.

6. A display cell according to claim 5, wherein said control electrodes are disposed in rows and columns, wherein a first and a second plurality of conductive tracks are disposed on said first plate between the latter and said liquid crystal layer and electrically isolated from each other, each track of said first plurality of tracks being disposed between two adjacent rows of said control electrodes and each track of said second plurality of tracks being disposed between two adjacent columns of said control electrodes, and wherein each of said electronic components is further connected to one track of said first plurality of tracks and to one track of said second plurality of tracks.

7. A display cell according to claim 1, wherein said first plate is disposed at the front of said cell, said control electrodes are disposed on said first plate, and said electronic components are disposed on said first plate between the latter and said liquid crystal layer.

8. A display cell according to claim 7, wherein said control electrodes are disposed in rows and columns, wherein a first and a second plurality of conductive tracks are disposed on said first plate between the latter and said liquid crystal layer and electrically isolated from each other, each track of said first plurality of tracks being disposed between two adjacent rows of said control electrodes and each track of said second plurality of tracks being disposed between two adjacent columns of said control electrodes, and wherein each of said electronic components is further connected to one track of said first plurality of tracks and to one track of said second plurality of tracks.

9. A liquid crystal display cell having a reflector-diffuser and at most one polarizer, comprising a layer of liquid crystal situated between a first transparent plate and a second plate, a plurality of control electrodes disposed in a display area between one of said plates and said liquid crystal layer, a counter electrode disposed between the other of said plates and said liquid crystal layer and a plurality of electronic components each linked to one of said control electrodes, wherein said control electrodes are transparent and disposed between said first plate and said liquid crystal layer, wherein said counter electrode is disposed between said second plate and said liquid crystal layer and is of a light reflecting material, and wherein the face of said counter electrode located adjacent to said liquid crystal layer is frosted over its entire surface situated in said display area, said counter electrode thus constituting said reflector-diffuser.

10. A display cell according to claim 9, wherein said first plate is disposed at the front of said cell, said control electrodes are disposed on said first plate, and said electronic components are disposed on said first plate between the latter and said liquid crystal layer.

11. A display cell according to claim 10, wherein said control electrodes are disposed in rows and columns, wherein a first and a second plurality of conductive tracks are disposed on said first plate between the latter and said liquid crystal layer and electrically isolated from each other, each track of said first plurality of tracks being disposed between two adjacent rows of said control electrodes and each track of said second plurality of tracks being disposed between two adjacent columns of said control electrodes, and wherein each of said electronic components is further connected to one track of said first plurality of tracks and to one track of said second plurality of tracks.

12. A display cell according to claim 9, wherein said counter electrode contacts the face of said second plate oriented towards said liquid crystal layer.