ELECTRIC FIELD DEVICE

• US 3,627,408 A
• Filed: 06/29/1965
• Issued: 12/14/1971
• Est. Priority Date: 06/29/1965
• Status: Expired due to Term

• Current Assignee: James L. Fergason
• Original Assignee: James L. Fergason
• Inventors: Fergason, James L.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Bauer, Edward S.
• Application Number:
  US04/467,852
• Time in Patent Office: 2,359 Days
• Field of Search: 23/253 350/160,161,16P,150 250/213 324/86 178/5.2 353/84
• US Class Current: 353/84
• 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 1/135 Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied G02F1/133348 takes precedence
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells
• CPC Class Codes: H04N 9/22 using the same beam for more than one primary colour information H04N9/27 takes precedence

Abstract

An electric field sensitive device for providing a visual indication in response to an electric field incorporating liquid crystalline materials of the type exhibiting the cholesteric phase.

Claims

1. A method of detecting an unknown electric field comprising the steps of providing a cholesteric liquid crystalline material, subjecting said cholesteric liquid crystalline material to said unknown electric field and observing a change in the optical properties of said cholesteric liquid crystalline material in response to the presence of said unknown electric field.

2. A method of detecting an electric field comprising the steps of providing a thin film of cholesteric liquid crystalline material exhibiting the property of different values of selective scattering of light in response to different values of electric field, subjecting said thin film to said electric field, illuminating said thin film with white light to provide a color indication for different values of electric field.

3. A method of detecting an electric field comprising the steps of providing a thin film of a cholesteric liquid crystalline material exhibiting the property of change in optical properties in response to an electric field, subjecting said thin film to said electric field, illuminating said thin film with electromagnetic radiations to provide means for detecting the optical properties of said thin film in response to said electric field.

4. A method of detecting an unknown electric field comprising the steps of providing a thin film of a material having a cholesteric liquid crystalline phase, impressing said unknown electric field across said thin film and observing color change of said thin film in response to the presence of said unknown electric field.

5. A method of detecting an unknown electric potential comprising the steps of providing a thin film of a material having a cholesteric liquid crystalline phase, impressing said unknown electric potential across thin film and to modify the selective scattering properties of said thin film to visually indicate a color change.

6. A method of modulating a light source comprising the steps of providing a thin film of a material having a cholesteric liquid crystalline phase, directing the radiation from said light source onto said thin film, impressing an electric quantity across said thin film to vary the optical properties of said thin film and modulate the light directed onto said thin film from said light source.

7. In combination, a layer of cholesteric liquid crystalline material exhibiting the property of change in the optical properties in response to an electric field, a first and second electrically conductive member for impressing a field across said layer of cholesteric liquid crystalline material, said first electrically conductive member transmissive to input radiations and means for directing said input radiations through said first electrically conductive member onto said thin film of cholesteric liquid crystalline material.

8. In combination, a thin film of cholesteric liquid crystalline material exhibiting different optical properties to different electric fields, a first and second electrical conductive member for impressing a field across said thin film of cholesteric liquid crystalline material, said first electrically conductive member being transmissive to light and means for input radiations directed through said first electrically conductive member onto said thin film of cholesteric liquid crystalline material to provide a visual indication of the optical property of said thin film.

9. In combination, a thin film of cholesteric liquid crystalline material exhibiting the property of selective scattering of light and of a first wavelength region in response to a first electric field and a second wavelength region in response to a second electric field, a first and second electrical conductive member for impressing a field across said thin film of cholesteric liquid crystalline material, said first electrically conductive member being transmissive to input radiations within said first and second wavelength regions, and means directing input radiations including said first and second wavelength regions through said transmissive member onto said thin film of cholesteric liquid crystalline material.

10. An article for detecting an electric field comprising a thin film of cholesteric liquid crystalline material and means for impressing said electric field there across.

11. An optical apparatus for controlling light within a discrete range of wavelengths of the light spectrum comprising a layer of cholesteric liquid crystalline material and means responsive to an electrical signal for impressing an electrical field across said layer.

12. A light-controlling device responsive to an electric field impressed thereacross comprising a thin film of a cholesteric liquid crystalline material that exhibits the property of selective scattering of radiations directed thereon, means for subjecting said thin film to an electric field to modify the dominant wavelength of the radiation scattering properties of said thin film and means for directing radiations from a source onto said thin film to provide scattering of selective wavelengths of radiations with the spectrum of said source.

13. An optiCal apparatus for controlling radiations within a selected range of wavelengths of the spectrum comprising a layer of cholesteric liquid crystalline material, said layer including 15 to 50 percent by weight of at least one material selected from the group consisting of cholesterol, cholesteryl chloride, cholesteryl bromide, cholesteryl iodide, cholestanol, cholestanyl chloride, cholestanyl bromide, cholestanyl iodide, sitosterol, sitosteryl chloride, sitosteryl bromine and sitosteryl iodide and electrically conductive means to impress a field across said layer.

14. An optical apparatus for controlling light within a selected range of wavelengths of the spectrum comprising a layer of cholesteric liquid crystalline material, said layer comprising 15 to 50 percent by weight of at least one material selected from the group consisting of cholesterol, cholesteryl chloride, cholesteryl iodide, cholesteryl bromide, cholestanol, cholestanyl chloride, cholestanyl bromide, cholestanyl iodide, sitosterol, sitosteryl chloride, sitosteryl bromide, sitosteryl iodine, and the balance including sterol derivatives and up to 20 percent of fatty acids and compounds thereof, and means for impressing an electric field across said layer for varying the optical properties of said layer.

15. An optical apparatus for controlling radiations comprising a layer of liquid crystalline material of the cholesteric phase including at least one material selected from the group consisting of cholesterol, cholestanol, sitosterol, cholesteryl halide, cholestanyl halide and sitosteryl halide and electrically conductive means for impressing an electric field across said layer.

16. A color television system comprising a thin film of a material having a cholesteric liquid crystalline phase, said film exhibiting the optical property of having a different dominant wave of selected scattering in the red, blue and green portions of the spectrum in response to different values of electric field applied thereto.

17. A projection system comprising a thin film of a material having a cholesteric liquid crystalline phase and exhibiting the property of different values of selective transmission of light in response to an electric field supplied thereacross, means for directing light from a source onto said liquid crystalline film, means for impressing different values of electric field across said liquid crystalline film for varying the transmission properties thereof and a screen member onto which a light image is projected through said liquid crystalline film from said source.

18. A method of detecting an electric field comprising the steps of providing a thin film of material containing a cholesteric liquid crystalline material, subjecting said film of material to said electric field and illuminating said film of material with light to provide a color indication for different values of electric field.

19. In combination, a layer of material containing a material in the cholesteric liquid crystalline phase exhibiting the property of changing optical properties in response to an electric field, a first and second electrically conductive member for impressing a field across said layer of material, said first electrically conductive member transmissive to input radiations and means for directing said input radiations through said first electrically conductive member onto said film of material.

20. An optical apparatus for controlling light within a discreet range of wavelengths of the light spectrum comprising a layer of material containing cholesterol nonanoate and means responsive to an electrical signal for impressing an electrical field across said layer.