Systems and methods for protecting against high-radiant-flux light based on time-of-flight

Patent metadata

Field	Value
Publication number	US-9948866-B2
Application number	US-201615011727-A
Country	US
Kind code	B2
Filing date	Feb 1, 2016
Priority date	Feb 1, 2016
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

Systems and methods for preventing high-radiant-flux light, such as laser light or a nuclear flash, from causing harm to imaging devices, such as a camera or telescope. In response to detection of high-radiant-flux light, the proposed systems have the feature in common that a shutter is closed sufficiently fast that light from the source will be blocked from reaching the image sensor of the imaging device. Some of the proposed systems include a folded optical path to increase the allowable reaction time to close the shutter.

First claim

The invention claimed is:

1. An imaging device comprising:
a laser sensor configured to output an activation signal in response to impingement thereon of light having a radiant flux greater than a specified threshold;
an image sensor comprising a multiplicity of elements that convert impinging light to electrical signals;
a first path-bending optical component disposed along an optical path that extends from a point in a vicinity of said laser sensor to said image sensor;
a first shutter disposed along a portion of said optical path that extends from said first path-bending optical component to said image sensor; and
a signal line connected to carry said activation signal from said laser sensor to said first shutter.

2. The imaging device as recited in claim 1 , wherein said laser sensor, said signal line and said first shutter are configured so that in response to first and second light beams, both having a radiant flux greater than said specified threshold, concurrently arriving at said laser sensor and a starting point of said optical path respectively, said first shutter will become opaque prior to said other light impinging thereon in response to receipt of said activation signal from said laser sensor via said signal line.

3. The imaging device as recited in claim 1 , wherein the optical path is configured to produce a time-of-flight delay for light traveling from the vicinity of said laser sensor to said first shutter, and said laser sensor, said signal line, and said first shutter are configured to produce a shutter delay from the time a high-radiant-flux arrives at said laser sensor to the time said first shutter becomes opaque, wherein the time-of-flight delay is greater than the shutter delay.

4. The imaging device as recited in claim 1 , wherein said first path-bending optical component comprises a first mirror.

5. The imaging device as recited in claim 4 , further comprising a second mirror disposed along said optical path, wherein light traveling along said optical path will be incident on a first portion of said first mirror, said second mirror, and a second portion of said first mirror in sequence, said first shutter being disposed along a portion of said optical path that extends from said second portion of said first mirror to said image sensor.

6. The imaging device as recited in claim 4 , further comprising a second mirror disposed along said optical path, wherein light traveling along said optical path will be incident on said first mirror and then said second mirror in sequence, said first shutter being intersected by a first portion of said optical path that extends from said first mirror to said second mirror and a second portion of said optical path that extends from said second mirror to said image sensor.

7. The imaging device as recited in claim 4 , further comprising a second mirror disposed along said optical path, wherein light traveling along said optical path will be incident on said first mirror and then said second mirror in sequence, said first shutter being disposed along a portion of said optical path that extends from said second mirror to said image sensor.

8. The imaging device as recited in claim 1 , wherein said image sensor comprises a focal plane array.

9. The imaging device as recited in claim 1 , further comprising a second shutter disposed along a portion of said optical path that extends from said first path-bending optical component to said first shutter.

10. The imaging device as recited in claim 9 , wherein said first shutter comprises an electro-optical shutter and said second shutter comprises a mechanical shutter.

11. An instrument comprising:
a laser sensor configured to output an activation signal in response to impingement thereon of light having a radiant flux greater than a specified threshold;
a first path-bending optical component disposed along an optical path that extends from a point in a vicinity of said laser sensor to a focal plane of the instrument;
a shutter disposed along a portion of said optical path that extends from said first path-bending optical component to said focal plane; and
a signal line connected to carry said activation signal from said laser sensor to said shutter.

12. The instrument as recited in claim 11 , wherein said laser sensor, said signal line and said shutter are configured so that in response to some light and other light, both having a radiant flux greater than said specified threshold, concurrently arriving at said laser sensor and a starting point of said optical path respectively, said shutter will become opaque prior to said other light impinging thereon in response to receipt of said activation signal from said laser sensor via said signal line.

13. The instrument as recited in claim 11 , wherein the optical path is configured to produce a time-of-flight delay for light traveling from the vicinity of said laser sensor to said shutter, and said laser sensor, said signal line, and said shutter are configured to produce a shutter delay from the time a high-radiant-flux light arrives at said laser sensor to the time said shutter becomes opaque, wherein the time-of-flight delay is greater than the shutter delay.

14. The instrument as recited in claim 11 , further comprising second, third and fourth path-bending optical components, wherein said second path-bending optical component is disposed along a portion of said optical path that extends from said first path-bending optical component to said focal plane, said third path-bending optical component is disposed along a portion of said optical path that extends from said second path-bending optical component to said focal plane, and said fourth path-bending optical component is disposed along a portion of said optical path that extends from said third path-bending optical component to said focal plane.

15. The instrument as recited in claim 14 , wherein each of said first through fourth path-bending optical components is one of a mirror and a facet of a prism.

16. The instrument as recited in claim 14 , further comprising an image sensor disposed at said focal plane.

17. An imaging device comprising:
a laser sensor configured to output an activation signal in response to impingement thereon of light having a radiant flux greater than a specified threshold;
an image sensor comprising a multiplicity of elements that convert impinging light to electrical signals;
means for increasing a time-of-flight of light along an optical path that extends from a point in a vicinity of said laser sensor to said image sensor;
a shutter disposed along a portion of said optical path that extends from said volume of substance having a high index of refraction to said image sensor; and
a signal line connected to carry said activation signal from said laser sensor to said first shutter.

18. The imaging device as recited in claim 17 , wherein said means for increasing a time-of-flight of light along an optical path comprise a volume of substance having a high index of refraction.

19. The imaging device as recited in claim 17 , wherein said means for increasing a time-of-flight of light along an optical path comprise one or more reflective surfaces.

20. The imaging device as recited in claim 17 , wherein said laser sensor, said signal line and said shutter are configured so that in response to some light and other light, both having a radiant flux greater than said specified threshold, concurrently arriving at said laser sensor and a starting point of said optical path respectively, said shutte

Assignees

• Boeing Co

Inventors

• Tillotson Brian J
• Neville Kathryn M

Classifications

• H04N23/73 Primary

  by influencing the exposure time · CPC title

• H04N23/55

  Optical parts specially adapted for electronic image sensors; Mounting thereof · CPC title

• G01S7/495

  Counter-measures or counter-counter-measures {using electronic or electro-optical means} · CPC title

• G02B26/04

  by periodically varying the intensity of light, e.g. using choppers (shutters, diaphragms for cameras G03B9/00; devices for eliminating or reducing the effect of flicker in projection systems G03B21/40) · CPC title

• G02B23/08

  Periscopes {(arrangements on floating structures of underwater viewing devices B63C11/49; arrangement of visual watch equipment on submarines B63G8/38)} · CPC title