Optical protection apparatus for use with night vision devices

• US 5,751,380 A
• Filed: 10/02/1995
• Issued: 05/12/1998
• Est. Priority Date: 10/02/1995
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Hanssen, Jeffrey Scott
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Dudek, James A.
• Application Number:
  US08/537,344
• Time in Patent Office: 953 Days
• Field of Search: 250/214 LA, 250/214 VT, 359/409, 349/1, 349/2, 349/13, 349/14
• US Class Current: 349/1
• CPC Class Codes: G02B 23/12 with means for image conversion or intensification
• CPC Class Codes: H04N 23/75 by influencing optical camera components

Abstract

An optical protection apparatus for preventing the degradation by bright ht of the performance of night vision devices which includes a first lens for focusing bright light from a light source onto a charge coupled device sensing array at its focal plane. Simultaneously, light from the source is imaged onto a liquid crystal television display which is positioned in front of the optical image sensing element for the night vision goggles. Raster scan and data processing circuit a first stream of digital data which represents the bright light image focused onto the charge coupled device sensing array. A video contrast enhancer generates a second stream of digital data which represents a negative image of the bright light image. This second stream of digital data is supplied to an electronics control module which generates alternating current drive signals for forming an opaque image on the liquid crystal television display at the position on the liquid crystal television display upon which the bright light image is incident. This opaque image prevents the bright light image from passing through the liquid crystal television display to the optical image sensing element for the night vision device.

Claims

1. An optical protection apparatus for protecting an optical image sensing element of a night vision device from a light source, said optical protection apparatus comprising:

first and second lens means spatially disposed from said light source along an optical path from said light source, said first and second lens means collecting and focusing light energy from said light source;

a sensing array spatially disposed from said first lens means at a focal plane of said first lens means along a first optical axis;

said first lens means collecting and focusing said light energy from said light source onto said sensing array means forming a spot of light energy on said sensing array means;

said sensing array generating a first stream of digital data representative of the spot of light energy formed on said sensing array means;

image inverting means coupled to said sensing array for receiving said first stream of digital data, said image inverting means processing said first stream of digital data to form a negative image of said spot of light energy, said image inverting means generating a second stream of digital data representative of the negative image of said first light spot;

an optical display spatially disposed from said second lens means at a focal plane of said second lens means along a second optical axis, said optical display being positioned directly in front of said optical image sensing element;

said second lens means collecting and focusing said light energy from said light source onto said optical display;

control circuit means coupled to said image inverting means and said optical display for receiving said second stream of digital data from said image inverting means, said control circuit means, responsive to said second stream of digital data, providing electrical drive signals to said optical display to form an opaque image on said optical display;

said opaque image being formed on said optical display at a location on said optical display to prevent said light energy from passing through said optical display to said optical image sensing element of said night vision device.

2. The optical protection apparatus of claim 1 wherein said first and second lens means each comprise a 16 millimeter, f/1.4 lens wherein f is the focal length of said lens.

3. The optical protection apparatus of claim 1 wherein said sensing array comprises:

a charge coupled device sensing array spatially disposed from said first lens means at said focal plane of said first lens means along said first optical axis; and

a raster scan and data processing circuit coupled to said charge coupled device sensing array.

4. The optical protection apparatus of claim 1 wherein said image inverting means comprises a video contrast enhancer.

5. The optical protection apparatus of claim 1 wherein said image inverting means comprises a dual channel time base corrector.

6. The optical protection apparatus of claim 1 wherein said optical display comprises a liquid crystal television display.

7. An optical protection apparatus for protecting an optical image sensing element of a night vision device from a light source, said optical protection apparatus comprising:

first and second lens spatially disposed from said light source along an optical path from said light source;

a charge coupled device sensing array spatially disposed from said first lens at a focal plane of said first lens along a first optical axis;

said first lens collecting and focusing light energy from said light source onto said charge coupled device sensing array forming a spot of light energy on said charge coupled device sensing array;

a raster scan and data processing circuit coupled to said charge coupled device sensing array for generating a first stream of digital data representative of the spot of light energy formed on said charge coupled device sensing array;

a video contrast enhancer coupled to said raster scan and data processing circuit to receive said first stream of digital data;

said video contrast enhancer processing said first stream of digital data to form a negative image of said spot of light energy, said video contrast enhancer generating a second stream of digital data representative of the negative image of said first light spot;

a liquid crystal television display spatially disposed from said second lens at a focal plane of said second lens along a second optical axis, said liquid crystal television display being positioned directly in front of said optical image sensing element;

said second lens collecting and focusing said light energy from said light source onto said liquid crystal television display; and

an electronics control module coupled to said video contrast enhancer and said liquid crystal television display for receiving said second stream of digital data from said video contrast enhancer, said electronics control module, responsive to said second stream of digital data, providing electrical drive signals to said liquid crystal television display to form an opaque image on said liquid crystal television display;

said opaque image being formed on said liquid crystal television display at a location on said liquid crystal television display to prevent said light energy from passing through said liquid crystal television display to said optical image sensing element of said night vision device.

8. The optical protection apparatus of claim 7 wherein said first and second lens means each comprise a 16 millimeter, f/1.4 lens wherein f is the focal length of said lens.

9. The optical protection apparatus of claim 7 wherein said video contrast enhancer comprises a dual channel time base corrector.