Opto-electronic device for detecting and locating a radiant source

• US 4,946,277 A
• Filed: 09/27/1988
• Issued: 08/07/1990
• Est. Priority Date: 10/02/1987
• Status: Expired due to Fees

• Current Assignee: Thomson-CSF
• Original Assignee: Thomson-CSF
• Inventors: Lemaire, Jean-Marc, Marquet, Patrice, Dunouvion, Philippe
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/249,894
• Time in Patent Office: 679 Days
• Field of Search: 356/141, 356/152, 250/237 R, 250/203 R
• US Class Current: 356/141.5
• CPC Class Codes: G01S 3/783 using amplitude comparison of signals derived from static detectors or detector systems

Abstract

The device permits a wide field of detection with high sensitivity and high locating precision. To this end, the device has a four-quadrant detector associated with a diaphragm formed by the central transparent zone of an opaque mask. The diaphragm preferably has a circular shape and no focusing lens. These elements are in parallel planes so that the line joining the centers of the diaphragm and the detector is perpendicular to these planes. The set is placed in a housing and is shielded by a transparent window. With a deviation measurement circuit that processes the detected signals, the assembly enables the computation of the angular offset of a pinpoint radiant source. With two elementary sensors of this type, it is possible to compute the spatial location of the source, for example a laser.

Claims

1. An opto-electronic device for detecting and locating radiant sources comprising:

--a plane, four-quadrant detector for producing four signals, one for each quadrant,

--an optical receiver preceding said detector and including a plane diaphragm parallel to the detector, formed by a transparent central zone of an opaque mask, so as to enable said detecting and locating of sources in a wide field of observation greater than ±

45°

in elevation and in azimuth, and

--circuits for processing and deviation measurement of the four signals detected by the quadrant detector to locate a direction of the source with respect to a reference optical direction of the device, formed by an axis of said field passing through a center of the detector and a center of the diaphragm wherein the central zone of said diaphragm is circular, and wherein the four-quadrant detector has a circular shape, and a diameter of the diaphragm is being equal to a radius of the four-quadrant detector.

2. A device according to claim 1 wherein the diaphragm is preceded by a transparent shielding window forming the front face of a housing within which are arranged the diaphragm and the detector.

3. A device according to claim 2 comprising an optic filter.

4. A device according to claim 3 wherein the optic filter is made by deposition on the face of the window inside the housing.

5. A device according to claim 1 comprising an optic filter.

6. An opto-electronic device for detecting and locating radiant sources comprising;

--a plane, four-quadrant detector for producing four signals, one for each quadrant,

--an optical receiver preceding said detector and including a plane diaphragm parallel to the detector, formed by a transparent central zone of an opaque mask, so as to enable said detecting and locating of sources in a wide field of observation greater than ±

45°

in elevation and in azimuth, and

--circuits for processing and deviation measurement of the four signals detected by the quadrant detector to locate a direction of the source with respect to a reference optical direction of the device, formed by an axis of said field passing through a center of the detector and a center of the diaphragm, wherein the central zone of said diaphragm is circular, and wherein the diaphragm can be adjusted to modify a diameter of the central zone and can also be shifted to modify its distance from the plane detector so as to modify its distance from the plane detector so as to modify the angular aperture of the field of observation.

7. A device according to claim 6 wherein the diaphragm is preceded by a transparent shielding window forming the front face of a housing within which are arranged the diaphragm and the detector.

8. A device according to claim 6 comprising an optic filter which is formed by deposition on the front face of the window inside the housing.

9. An opto-electronic device for detecting and locating radiant sources in a wide field of observation comprising:

--an optical receiver receiving unfocussed radiant energy from said radiant sources, comprising a plane diaphragm having a specified aperture with a center O'"'"', said plane diaphragm formed by a transparent central zone of an opaque mask;

--a plane detector located to receive unfocussed radiant energy from said optical receiver, having four quadrants which are bounded by two orthogonal axis OX, OY, where O is a center of said plane detector, for respectively detecting four signals, one indicative of radiant energy on each said quadrant, when a radiant source is in the field of observation, said diaphragm and said detector being parallel, and orthogonal to an axis OO'"'"' between said center O and said center O'"'"' which axis is a reference optical direction for the device, and

--means for processing and deviation measurement, receiving the for signals, and determining a direction of said source in relation to said reference optical direction for a deviation measurement curve determined according to a distance D between a plane in which said diaphragm is located and a plane in which said detector is located and to a shape and dimension of the aperture of said diaphragm.

10. A device according to claim 9 further comprising a housing having a transparent shielding window forming a front face of a housing, within which the diaphragm and the detector are placed.

11. A device according to claim 10 further comprising an optical filter made by deposition on the face of the window inside the housing.

12. A device according to claim 11 wherein the diaphragm can be adjusted to modify a diameter of the aperture and can also be shifted to modify its distance from the plane detector so as to modify an angular aperture of the field of observation.

13. A device according to claim 9, wherein the aperture of said diaphragm and said detector have circular shapes.

14. A device according to claim 13, wherein a diameter of the aperture of said diaphragm is equal to a radius of the detector.

15. A device as in claim 13 wherein said processing means calculates EX and EY from a center O according to the equations:

##EQU2## where V1-V4 are signals from a first quadrant through a fourth quadrant respectively.

16. An opto-electronic device for detecting and locating radiant sources in a wide field of observation comprising:

a light receiver assembly which has no focusing device consisting essentially of;

(a) an optical receiver comprising a plane diaphragm having a specified aperture with a center O'"'"', said plane diaphragm formed by a transparent central cone of an opaque mask; and

(b) a plane detector having four quadrants which are bounded by two orthogonal axis oX, OY where O is a center of said plane detector, for respectively detecting four signals, one indicative of radiant energy on each said quadrant, when a radiant source is in the field of observation, said diaphragm and said detector being parallel, and orthogonal to an axis OO'"'"' between which is a reference optical direction for the device, and

--means for processing and deviation measurement, receiving the four signals, and determining a direction of said source in relation to said reference optical direction from a deviation measurement curve determined according to a distance D between a plane of said diaphragm and a plane of said detector and to a shape and dimension of the aperture of said diaphragm.

17. A device according to claim 16 further comprising a housing having a transparent shielding window forming a front face of a housing within which said light receiver assembly is placed.

18. A device according to claim 17 further comprising an optical filter made by deposition on the face of the window inside the housing.