Field sensitive optical displays, generation of fields therefor and scanning thereof

• US 4,493,531 A
• Filed: 04/01/1983
• Issued: 01/15/1985
• Est. Priority Date: 07/03/1980
• Status: Expired due to Fees

• Current Assignee: Control Interface Company Limited
• Original Assignee: Control Interface Company Limited
• Inventors: Bohmer, William, Betancourt, Walter J., Hoffman, Louis S.
• Primary Examiner(s): Corbin, John K.
• Application Number:
  US06/479,349
• Time in Patent Office: 655 Days
• Field of Search: 350/330, 350/331 R, 350/332-341, 350/347 D, 350/347 E, 350/352, 340/785, 313/463, 315/169.3
• US Class Current: 349/143
• CPC Class Codes: G02F 1/133 Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements arrangements or circuits for control of liquid crystal elements in a matrix, not structurally associated with these elements G09G3/36
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/134336 Matrix
• CPC Class Codes: G02F 1/1345 Conductors connecting electrodes to cell terminals
• 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

Abstract

Disclosed are field sensitive optical displays, and arrangements and methods for inducing fields in the displays and for scanning the displays. In the disclosed embodiments, liquid crystal, optoceramic and electroluminescent materials are utilized. Methods and arrangements for improving the response time of twisted nematic liquid crystal material and for generating color displays are also disclosed. Methods and arrangements are also disclosed for superimposing varying and a dc fields in field sensitive material. Various display patterns such as a movable dot, intersecting lines and a pivoting line can be obtained.

Claims

1. A field sensitive display device for forming a display when subjected to visible light comprising a field sensitive material, spaced electrodes for inducing a field, means for containing the field sensitive material with the spaced electrodes and the field sensitive material being relatively disposed so that a field induced by the spaced electrodes is capable of affecting the field sensitive material, a first of the spaced electrodes including an impedance portion and a plurality of conductive, substantially low impedance portions connected to different electrical locations of the impedance portion and extending therefrom, first terminal means connected to the impedance portion for applying an electrical signal thereto, a first capacitance electrically coupled with each of the conductive substantially low impedance portions, a second of the spaced electrodes including a conductive substantially low impedance portion, second terminal means connected to the second electrode for applying an electrical signal thereto, a second capacitance electrically coupled with the conductive substantially low impedance portion of the second electrode, and additional terminal means connected to the first and second capacitances for applying at least one electrical signal thereto.

2. A device according to claim 1, wherein the containing means comprise spaced plates, the field sensitive material being disposed between the plates and the electrodes.

3. A device according to claim 2, wherein the plates are transparent.

4. A device according to claim 2, wherein one of the plates is transparent and the other is reflective.

5. A device according to claim 1, wherein the impedance portion of the first electrode is a linearly-extending resistance which is disposed parallel to one side of a first plate and the conductive, substantially low impedance portions are conductive, substantially non-resistive strips extending transversely from the linearly-extending resistance.

6. A device according to claim 5, wherein the conductive, substantially low impedance portion of the second electrode extends uniformly parallel to and substantially coextensive with a second plate opposed to the conductive, substantially low impedance portions of the first electrode.

7. A device according to claim 5, wherein the second electrode comprises a linearly-extending resistive portion disposed adjacent one side of a second plate and a plurality of conductive, substantially non-resistive strips electrically connected to different resistive locations of the resistive portion and extending parallel to the second plate and transversely to the resistive portion, the conductive strips of the two electrodes extending transversely to one another generally in a grid pattern with the field sensitive material being disposed between the conductive strips of the electrodes.

8. A device according to claim 5, wherein the second electrode comprises a linearly-extending resistive portion disposed adjacent one side of a second plate and a plurality of conductive, substantially non-resistive strips electrically connected to different resistive locations of the resistive portion and extending parallel to the second plate and transversely to the resistive portion, the conductive strips of the two electrodes extending parallel to and coextensively with one another with the field sensitive material being disposed between the conductive strips of the electrodes.

9. A device according to claim 15, wherein the second electrode comprises a linearly-extending resistive portion and a plurality of conductive, substantially non-resistive strips electrically connected to different resistive locations of the resistive portion and extending transversely from the resistive portion, the first and second electrodes being disposed substantially coplanar, the resistive portions of the first and second electrode being spaced and the conductive strips being interleaved with the conductive strips of the first electrode extending towards the resistive portion of the second electrode and the conductive strips of the second electrode extending towards the resistive portion of the first electrode.

10. A device according to claim 1, wherein the first and second capacitances comprise an insulating layer contacting the low impedance portions of each of the electrodes and a conductive, substantially low impedance layer contacting and superposed on the insulating layer, the additional terminal means comprising a respective terminal connected to each of the low impedance layers.

11. A device according to claim 1, wherein the first and second capacitances are strip-like, the first strip-like capacitance extending transversely to the low impedance portions of the first electrode.

12. A device according to claim 1, wherein the first and second capacitances extend substantially coextensively with the low impedance portions of the first and second electrodes.

13. A device according to claim 1, wherein the field sensitive material comprises a liquid crystal material.

14. A device according to claim 13, wherein the liquid crystal material is a nematic liquid crystal material.

15. A device according to claim 14, wherein the nematic liquid crystal material is a dynamic scattering material.

16. A device according to claim 14, wherein the nematic liquid crystal material is a quiescent scattering material.

17. A device according to claim 14, wherein the nematic liquid crystal material is a twisted material and further comprising means for aligning the twisted material to cause rotation of the plane of polarization of plane polarized light passing through the material in the absence of a field.

18. A device according to claim 12, wherein the liquid crystal material comprises a mixture of a nematic liquid crystal material and a cholesteric liquid crystal material.

19. A device according to claim 11, wherein the field sensitive material comprises an optoceramic material.

20. A device according to claim 19, wherein the optoceramic material is in the form of a wafer, the device including a means disposed between the plates for supporting the wafer.

21. A device according to claim 1, wherein the field sensitive material comprises a field-excited material.

22. A device according to claim 21, wherein the field-excited material is an electroluminescent material.

23. A device according to claim 1, wherein the low impedance portions of the first electrode have a predetermined width and are spaced apart to define intervals of predetermined width between adjacent low impedance portions, and wherein the field sensitive material comprises a twisted nematic liquid crystal material, the device including means for aligning the material to cause rotation of the plane of polarization plane polarized light passing through the material in the absence of a field.

24. A device according to claim 23, wherein the width of the low impedance portions and the width of the intervals are approximately equal.

25. The device according to claim 1, wherein the field sensitive material is a liquid crystal material, and further comprising another said field sensitive display device in which the field sensitive material is a twisted nematic liquid crystal material and two plane polarizer means for passing light polarized in one predetermined plane and blocking light polarized a plane disposed at an angle to the predetermined plane, said other device being disposed between said plane polarizer means which are arranged to pass light polarized in planes disposed at an angle to one another, said other device selectively producing colored light when light is applied thereto and being aligned with said device to selectively transmit colored light therethrough.