Eye safe laser imaging system

• US 5,383,200 A
• Filed: 12/20/1993
• Issued: 01/17/1995
• Est. Priority Date: 12/20/1993
• Status: Expired due to Term

• Current Assignee: Alliedsignal Inc.
• Original Assignee: Alliedsignal Inc.
• Inventors: Yee, Joseph, Rapoport, William R., Barrett, Joseph J.
• Primary Examiner(s): Epps, Georgia Y.
• Application Number:
  US08/169,289
• Time in Patent Office: 393 Days
• Field of Search: 372/30, 372/29, 372/25, 250/214 VT, 250/227.2, 356/318, 342/54
• US Class Current: 372/25
• CPC Class Codes: G02B 23/12 with means for image conversion or intensification
• CPC Class Codes: H01S 3/16 Solid materials
• CPC Class Codes: H01S 3/161 holmium
• CPC Class Codes: H01S 3/1616 thulium

Abstract

An active night vision system capable of viewing a target over long distances utilizes laser illumination in eye-safe, invisible wavelength regions of about 1.52-1.76 μm or about 2.03 μm-2.34 μm for illuminating a target; and electronically receives, intensifies and displays or stores the reflected image.

Claims

1. An active night vision system capable of viewing a target over long distances comprising, in combination,

(a) laser means for emitting a beam of coherent radiation having wavelength of from about 1.52 μ

m to about 1.76 μ

m or of from about 2.03 μ

m to about 2.34 μ

m for illuminating a target;

(b) receiving means for receiving an image of the reflected radiation from said target and for transforming the optical image into an electronic signal; and

(c) means for electronically storing and/or displaying the image received by said receiving means.

2. The active night vision system of claim 1 wherein the laser means is adapted to emit a beam of coherent radiation having wavelength of from about 1.52 μ

m to about 1.76 μ

m, at an intensity of up to about 1.0 Joules/cm².

3. The active night vision system of claim 1 wherein the laser means is adapted to emit a beam of coherent radiation having wavelength of from about 2.03 μ

m to about 2.34 μ

m, at an intensity of up to about 0.1 Joules/cm².

4. The active night vision system of claims 1, 2 or 3 wherein the laser means is adapted for pulsed operation.

5. The method of viewing a target which comprises the steps of

(a) illuminating the target with coherent radiation having wavelength of from about 1.52 μ

m to about 1.76 μ

m or of from about 2.03 μ

m to about 2.34 μ

m;

(b) sensing the radiation reflected from the illuminated target in said wavelength ranges of from about 1.52 μ

m to about 1.76 μ

m or of from about 2.03 μ

m to about 2.34 μ

m;

(c) intensifying said sensed reflected radiation; and

(d) displaying said intensified, sensed reflected radiation.

6. The method of claim 5 wherein said target is illuminated with coherent radiation having wavelength of from about 1.52 μ

m to about 1.76 μ

m at an intensity not exceeding about 1.0 Joules/cm².

7. The method of claim 5 wherein said target is illuminated with coherent radiation having wavelength of from about 2.03 μ

m to about 2.34 μ

m at an intensity not exceeding about 0.1 Joules/cm².

8. The method of claims 5, 6 or 7 wherein said target is illuminated by pulsed coherent radiation.

9. The method of claims 5, 6 or 7 wherein said target is illuminated by coherent radiation pulsed at a rate of from about 1 to about 30 pulses pulses per second.

10. The method of claims 5, 6 or 7 wherein said target is illuminated by pulsed coherent radiation which generates a single complete image of the target per pulse.

11. The method of claims 5, 6 or 7 wherein said target is illuminated by coherent radiation pulsed at a rate of from about 1 to about 30 pulses pulses per second, and wherein each pulse generates a single complete image of the target.