Optical modulator

• US 4,701,021 A
• Filed: 10/18/1984
• Issued: 10/20/1987
• Est. Priority Date: 10/21/1983
• Status: Expired due to Fees

• Current Assignee: Thomson-CSF (Thales SA)
• Original Assignee: Thomson-CSF (Thales SA)
• Inventors: Mourey, Bruno, Le Pesant, Jean-Pierre, Hareng, Michel, Perbet, Jean-Noel
• Primary Examiner(s): Arnold, Bruce Y.
• Application Number:
  US06/662,156
• Time in Patent Office: 1,097 Days
• Field of Search: 350/267, 350/269, 350/355-357
• US Class Current: 359/228
• CPC Class Codes: G02B 26/005 based on electrowetting
• CPC Class Codes: G02B 5/24 Liquid filters G02B5/23 takes precedence

Abstract

Optical modulator of a light beam comprising cells employing the displacement of an absorbent liquid and arranged in series on the path of the beam with a liquid displacement cell permitting a reflection of the beam.

Claims

1. An optical modulator of a light beam comprising:

a plurality of cells each of which comprise;

two transparent plates separated one from the other;

spacing means for holding said transparent plates apart;

capillary space between said two transparent plates;

reservoir means located between said two transparent plates for containing at least one fluid;

electrical field producing means for applying an electrical field between said transparent plates for controlling the displacement of the fluid contained in said reservoir means between said reservoir means and said capillary space, wherein said fluid will be located in said reservoir means in response to the presence of said electrical field;

measuring means for measuring the intensity of a light beam and for outputting a signal indicative of the measured light;

control means coupled to said measuring means and the electrical field producing means of each of said cells for providing control information for activation of said electrical field producing means in response to said signal indications of said measured light;

wherein at least one of said cells is positioned in such a manner such that the capillary space is perpendicular to the direction of said light beam.

2. An optical modulator according to claim 1 comprising:

at least one cell as defined in claim 1;

a second cell as defined in claim 1 whose transparent plates are placed in said optical modulator so as to be obliquely positioned in the direction of said light beam, with the capillary space of said second cell being positioned in the section of the beam; and

the fluid of said second cell being transparent wherein, when said fluid is in the capillary space, the light beam is transmitted without deflection and, when the fluid is in the reservoir, the beam is deflected, and further, wherein said control means selectively controls at least one of said cells.

3. An optical modulator according to claim 2, comprising:

two triangular prisms with one face of each of them inclined to the direction of the light beam, with a cell being placed between the two aforementioned inclined faces, in such a way

wherein when the fluid is present in the capillary space said cell - prism assembly transmits the light without deflecting it, and further when the fluid in the capillary is absent, the inner walls of the transparent plates of the cell deflect the light.

4. An optical modulator according to claim 2, wherein the distance between the plates at the reservoir means is the same as the distance between the plates at the capillary space.

5. An optical modulator according to claim 2, wherein the reservoir means of cells which are positioned perpendicular to said light beam are placed on either side of the capillary space and;

wherein said reservoir means are positioned parallel to the direction of the light beam.

6. An optical modulator according to claim 1, comprising:

several cells having their transparent plates aligned perpendicular to the path of the light beam, wherein said control means controls the electrical field producing means of each of said cells such that different degrees of modulation of the light beam occur.

7. An optical modulator according to claim 1, wherein the fluid in cells which are aligned perpendicular to said light beam consists of a liquid mixture which absorbs a given range of wavelengths.

8. An optical modulator according to claim 1 wherein, within a cell, the spacing between the two plates defining a reservoir exceeds the spacing of the two plates defining the capillary space of the same cell.

9. An optical modulator according to claim 1, wherein the capillary space of cells are positioned perpendicular to said light beam and a single reservoir is placed at one end of the capillary space.

10. An optical modulator according to claim 1, wherein a plurality of cells as defined in claim 1 forming a first group of cells are juxtaposed in a first plane perpendicular to the direction of the light beam, with a plurality of cells as defined in claim 1 forming a second group of cells are juxtaposed in a second plane perpendicular to the direction of the light beam, so as to form a modulator system.

11. An optical modulator according to claim 10, further comprising:

absorbent screens parallel to the direction of the light beam and separating said second group of cells.

12. An optical modulator according to claim 10, wherein the capillary space of the cells of the second group are arranged perpendicular to the capillary space of the cells of the first group.

13. An optical modulator according to claim 1, wherein said control means controls, as a function of the signal from said measuring means all the cells that are in a common plane.