Projection display device

• US 4,249,796 A
• Filed: 06/21/1979
• Issued: 02/10/1981
• Est. Priority Date: 06/21/1979
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Gordon, Joseph G. II, Sincerbox, Glenn T.
• Primary Examiner(s): Rosenberger, Richard A.
• Application Number:
  US06/050,590
• Time in Patent Office: 600 Days
• Field of Search: 350/147, 350/150, 350/355, 350/356, 350/357, 350/285, 350/347 V, 356/369
• US Class Current: 359/241
• CPC Class Codes: G02F 1/195 by using frustrated reflection digital reflection using controlled total internal reflection G02F1/315

Abstract

A projection display device is provided in which variation in the index of refraction is used to modulate attenuated total reflection.

Claims

1. A projection display device comprising:

(a) a prism having a base;

(b) a thin film of material having a negative dielectric constant and having one side in optical contact with the base of said prism, and a second side;

(c) a medium of variable refractive index in contact with said second side of said film;

(d) means to pass a beam of light which is plane polarized in the plane of incidence onto the base of said prism at an angle to excite a surface electromagnetic wave at the interface between said medium and said film; and

(e) means to vary the refractive index of said medium.

2. A device as claimed in claim 1 wherein the refractive index of the medium is varied by means of an electrochemical reaction.

3. A device as claimed in claim 1 wherein the refractive index of the medium is varied by means of a photochromic reaction.

4. A device as claimed in claim 1 wherein the refractive index of the medium is varied by means of electrochromism.

5. A device as claimed in claim 1 wherein the refractive index of the medium is varied by means of electrophoresis.

6. A device as claimed in claim 1 wherein the refractive index of the medium is varied by means of molecular reorientation.

7. A device as claimed in claim 1 wherein said surface electromagnetic wave is a surface plasmon.

8. A device as claimed in claim 1 wherein said surface electromagnetic wave is a surface polariton.