Proximity fuse optical radiation receiver having wedge-shaped damping filter positioned adjacent photocell

• US 4,896,031 A
• Filed: 06/10/1988
• Issued: 01/23/1990
• Est. Priority Date: 12/11/1986
• Status: Expired due to Term

• Current Assignee: Aktiebolaget Bofors
• Original Assignee: Bofors Defence AB (BAE Systems Plc)
• Inventors: Pettersson, Erland, Knutz, Ola, Witt, Bengt
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Oen, William L.
• Application Number:
  US07/205,255
• Time in Patent Office: 592 Days
• Field of Search: 250/203 R, 250/561, 250/203 S, 250/201 AF, 356/1, 356/4, 356/141, 356/152
• US Class Current: 250/237.00R
• CPC Class Codes: F42C 13/023 using active distance measurement
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: G01S 7/4817 relating to scanning

Abstract

A receiver for receiving optical radiation includes detectors which, on reception, emit an electric signal. The detectors are operative to emit an electric signal of a level which is substantially independent of the angle of incidence of the optical radiation on the receiver.

Claims

1. In a proximity fuse for a launchable unit, an apparatus including a transmitter which transmits optical radiation reflectable against a target surface and a receiver provided with a detector device for generating an electric signal on receipt of the radiation reflected from the target surface and impinging upon the receiver/detector at different angles of incidence depending upon the distance of the target surface from the unit, wherein the receiver comprises:

a fixed mechanical/optical arrangement including a radiation damping filter, collimator lens, mirror and gap for distributing the received radiation to the surface of the detector device to render the sensitivity of the apparatus to depend upon angles of incidence in such a manner that the electric signal emitted by the detector device will be substantially independent of said distance within the entire scanning region of the proximity fuse.

2. The apparatus as claimed in claim 1, wherein a radiation damping filter is cuneiform in its vertical section and is disposed above the surface of the detector device, such that the value of the electric signal substantially independent of the angles of incidence will be realized by conveyance of the optical radiation to different parts of the surface of the detector device.

3. The apparatus as claimed in claim 1 wherein the optical radiation received within the total incidence angle sector passes the collimator lens;

and

wherein the surface of the detector device is obliquely inclined such that the focal point of the optical radiation will fall in, under or above the surface of the detector in response to the angle of incidence of the optical radiation.

4. The apparatus as claimed in claim 1 wherein the surface of the detector device receives the optical radiation after the same is reflected from a mirror, the optical radiation disposing at the surface of the detector device in a first incidence angle sector.

5. The apparatus as claimed in claim 1, wherein the surface of the detector device is directly exposable, via a gap, to optical radiation which impinges on the surface within a second incidence angle sector.

6. The apparatus as claimed in claim 5, wherein the mirror comprises a diffuse mirror.

7. The apparatus as claimed in claim 1, wherein the surface of the detector device receives the optical radiation through the collimator lens and reflection from a diffuse mirror in a third incidence angle sector.

8. The apparatus as claimed in claim 1, wherein the surface of the detector device receives the optical radiation through the collimator lens in a fourth incidence angle sector.

9. The apparatus as claimed in claim 1, wherein the surface of the detector device is placed substantially parallel along a longitudinal axis of the unit which is provided with the receiver, a diffuse mirror being obliquely inclined above the surface of the detector device, the collimator lens being disposed substantially at right angles in relation to the mirror and at the upper edge thereof, and the gap being obliquely inclined in relation to the detector surface such that imaginary extensions of the gap and the mirror effect an acute angle.

10. The apparatus as claimed in claim 2 wherein the optical radiation received within the total incidence angle sector passes the collimator lens;

and

wherein the surface of the detector device is obliquely inclined such that the focal point of the optical radiation will fall in, under or above the surface of the detector in response to the angle of the incidence of the optical radiation.

11. The apparatus as claimed in claim 2 wherein the surface of the detector device receives the optical radiation after the same is reflected from a mirror, the optical radiation disposing at the surface of the detector device in a first incidence angle sector.

12. The apparatus as claimed in claim 2, wherein the surface of the detector device is directly exposable, via a gap, to optical radiation which impinges on the surface within a second incidence angle sector.

13. The apparatus as claimed in claim 4, wherein the surface of the detector device is directly exposable, via a gap, to optical radiation which impinges on the surface within a second incidence angle sector.

14. The apparatus as claimed in claim 2, wherein the surface of the detector device receives the optical radiation through the collimator lens and reflection from diffuse mirror in a third incidence angle sector.

15. The apparatus as claimed in claim 3, wherein the surface of the detector device receives the optical radiation through the collimator lens and reflection from a diffuse mirror in a third incidence angle sector.

16. The apparatus as claimed in claim 4, wherein the surface of the detector device receives the optical radiation through the collimator lens and reflection from a diffuse mirror in a third incidence angle sector.

17. The apparatus as claimed in claim 5, wherein the surface of the detector device receives the optical radiation through the collimator lens and reflection from a diffuse mirror in a third incidence angle sector.

18. The apparatus as claimed in claim 6, wherein the surface of the detector device receives the optical radiation through a the collimator lens and reflection from the diffuse mirror in a third incidence angle sector.

19. The apparatus as claimed in claim 2, wherein the surface of the detector device receives the optical radiation through the collimator lens in a fourth incidence angle sector.

20. The apparatus as claimed in claim 3, wherein the surface of the detector device receives the optical radiation through the collimator lens in a fourth incidence angle sector.

21. The apparatus as claimed in claim 4, wherein the surface of the detector device receives the optical radiation through the collimator lens in a fourth incidence angle sector.

22. The apparatus as claimed in claim 5, wherein the surface of the detector device receives the optical radiation through the collimator lens in a fourth incidence angle sector.

23. The apparatus as claimed in claim 6, wherein the surface of the detector device receives the optical radiation through the collimator lens in a fourth incidence angle sector.

24. The apparatus as claimed in claim 7, wherein the surface of the detector device receives the opticl radiation through the collimator lens in a fourth incidence angle sector.