AC biased and resonated liquid crystal display

• US 3,991,416 A
• Filed: 09/18/1975
• Issued: 11/09/1976
• Est. Priority Date: 09/18/1975
• Status: Expired due to Term

• Current Assignee: Hughes Aircraft Company (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Little, Michael J., Ernstoff, Michael N., Byles, William R., Jensen, John E.
• Primary Examiner(s): Curtis, Marshall M.
• Application Number:
  US05/614,463
• Time in Patent Office: 418 Days
• Field of Search: 58/23 R, 58/23 BA, 350/160 LC, 340/324 M, 340/324 R, 340/336
• US Class Current: 345/87
• CPC Class Codes: G02F 1/13306 Circuit arrangements or driving methods for the control of single liquid crystal cells G02F1/132, G02F1/133382 take precedence

Abstract

A liquid crystal device biased by an alternating current having a predetermined frequency higher than the dispersion frequency of the liquid crystal material. The liquid crystal device exhibits inherent capacitance across its input terminals which is resonated by an inductor to result in a higher bias current and reduction of image smear of images displayed by such device.

Claims

1. A liquid crystal cell having electrodes and liquid crystal material therebetween, biased by an alternating current source at a predetermined alternating current frequency during operative mode of said cell, said cell exhibiting capacitance across said electrodes, the improvement comprising:

an inductor electrically connected to at least one of said electrodes and to said source, forming a resonant circuit with said capacitance at the predetermined frequency.

2. The invention as stated in claim 1, wherein the predetermined frequency is higher than the dispersion frequency of the liquid crystal material.

3. The invention as stated in claim 1, wherein the inductor is serially connected between the electrodes and source.

4. The invention as stated in claim 1, wherein the inductor is connected in parallel with the electrodes and the source.

5. A method for increasing performance of a liquid crystal cell biased at a predetermined frequency, comprising the steps of:

biasing the cell with an alternating current having a frequency greater than dispersion frequency of the liquid crystal material in said cell during operative mode of the cell; and

resonating the inherent capacitance of the liquid crystal cell with an inductor, connected to the cell and the source, at the predetermined bias frequency.

6. The method as in claim 5, wherein the inductor forms a series resonant circuit with the inherent capacitance of the cell.

7. The method as in claim 5, wherein the inductor forms a parallel resonant circuit with the inherent capacitance of the cell.