Electro-optical digital display

• US 3,955,190 A
• Filed: 09/11/1973
• Issued: 05/04/1976
• Est. Priority Date: 09/11/1972
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Suwa Seikosha
• Original Assignee: Kabushiki Kaisha Suwa Seikosha
• Inventors: Teraishi, Katsuhiro
• Primary Examiner(s): Curtis, Marshall M.
• Application Number:
  US05/396,341
• Time in Patent Office: 966 Days
• Field of Search: 350/150, 350/157, 350/160 LC, 350/160 P, 340/324 M, 340/324 R, 340/336, 58/50, 58/23
• US Class Current: 345/32
• CPC Class Codes: G02F 1/055 the active material being a ceramic G02F1/035 takes precedence
• CPC Class Codes: G04G 9/0023 by light valves in general G04G9/06, G04G9/12 takes precedence; electro-, magneto- or acousto-optic devices in general G02F1/00
• CPC Class Codes: G04G 9/12 using light valves, e.g. liquid crystals

Abstract

An electro-optical digital display particularly suited for use in an electronic wristwatch is provided. The display includes a transparent ceramic material formed as a plate having a pair of opposed major surfaces. Circuitry selectively applying an electric field to the ceramic material, the circuitry including a first transparent electrode engaging a first major surface of the plate and a second reflective electrode adapted to reflect light incident thereon provided from the second major surface of the plate. The first transparent electrode is segmented to define selected regions of application of an electric field to the selective regions of a ceramic plate. A polarization device for circular polarization is disposed adjacent the transparent electrode in the path of incident light upon the transparent electrode, incident light being reflected at selected regions by the reflective electrode in response to the selective energization of the segmented and reflective electrodes, the plate appearing opaque to incident light in the absence of such selective energization.

Claims

1. An electro-optical digital display assembly comprising a transparent ceramic material formed as a plate having a pair of opposed major surfaces, a first major surface of said plate including a first transparent electrode affixed thereto, a second major surface of said plate including a second light reflective electrode affixed thereto, said first transparent electrode being segmented to define selected regions of said ceramic plate therebetween, circular polarization means including a polarization plate overlying said transparent electrode, and circuit means respectively coupled to said first transparent electrode and said second reflective electrode, said circuit means being adapted to selectively apply an electric field to said selective regions defined thereby so that light incident upon said ceramic plate having passed through said polarizing means and through selecting region of said plate is reflected by said reflective electrode in response to the selected application of an electric field to said segmented reflective electrodes at said selected regions, said selected regions remaining opaque to incident light in the absence of electric fields selectively applied thereto.

2. An electro-optical digital display as in claim 1, wherein at least said segmented electrode is formed so that selective energization of groups of segments thereof can selectively define a character to be viewed, and said selective energization means including complementary MOS transistors adapted to apply selective energization signals having a fixed period to said electrode.

3. An electro-optical digital display as recited in claim 1, wherein said polarization means further includes a polarizing plate of a 1/4 wavelength.

4. An electro-optical display as recited in claim 1 wherein said plate is formed on at least one surface thereof with a plurality of parallel grooves to define a projection therebetween, said segmented electrodes on said surface including a pair of lineally extending strips positioned on opposed sides of said projection.

5. An electro-optical display as recited in claim 1 including a further transparent electrode segment strip extending along the top surface of each of said projections intermediate said first-mentiond strip segments.

6. An electro-optical digital display as claimed in claim 1, wherein said ceramic plate is bent in the plane of said major surfaces to apply a mechanical stress thereto, said bending of said plate effecting a pulling stress to the region of said first surface.

7. An electro-optical digital display assembly as claimed in claim 1, wherein said ceramic plate is formed of a substantially optically isotropic PLTZ material.