Radiant energy transducing apparatus with constructive occlusion

• US 5,914,487 A
• Filed: 01/16/1998
• Issued: 06/22/1999
• Est. Priority Date: 01/22/1997
• Status: Expired due to Term

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Original Assignee: Advanced Optical Technologies, LLC
• Inventors: Ritter, Michael P., Epling, Bobby L., Watson, Harold E., Schmitt, Mark G., Rains, Jack C. Jr., Ramer, David P.
• Primary Examiner(s): ALLEN, STEPHONE B
• Application Number:
  US08/836,811
• Time in Patent Office: 522 Days
• Field of Search: 250/203.1, 250/203.3, 250/203.4, 250/203.6, 250/206.1, 250/216, 250/228, 250/237 G, 356/121, 356/236, 356/375
• US Class Current: 250/237.00R
• CPC Class Codes: G01J 1/04 Optical or mechanical part supplementary adjustable parts
• CPC Class Codes: G01J 1/0407 Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
• CPC Class Codes: G01J 1/0437 using masks, aperture plates, spatial light modulators, spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 1/06 Restricting the angle of incident light
• CPC Class Codes: G01J 1/4228 arrangements with two or more detectors, e.g. for sensitivity compensation
• CPC Class Codes: G01J 2001/0481 Preset integrating sphere or cavity

Abstract

A radiant energy transducer system includes a base. The base has a diffusely reflective surface and an optical area defining a horizon district with respect to the transducer system. A mask occludes a portion of the optical area so as to present a substantially constant portion of the optical area over a range of angles above the horizon district. An electromagnetic transducer converts between radiation associated with the optical area and corresponding signals. Examples of the transducing systems provide emission of radiant energy with a tailored intensity distribution over an area illuminated by the system. Other examples of the transducing systems detect radiant energy, and the position of the mask relative to the optical area of the detector system serves to tailor the sensitivity of the detector over a field of view. The emitters and detectors can be used together, for example in a system for tracking the position of an object.

Claims

1. A radiant energy transducing apparatus comprising:

a base having a diffusely reflective surface and an optical area defining a horizon district with respect to the transducing apparatus;

a mask spaced from the base and positioned to occlude a portion of the optical area so as to present a substantially constant portion of the optical area over a range of angles above the horizon district; and

an electromagnetic transducer transducing between radiation associated with the optical area and corresponding signals.

2. An apparatus as in claim 1, wherein the base comprises a diffusely reflective cavity, and the optical area is an aperture of the cavity.

3. An apparatus as in claim 2, wherein the cavity is substantially hemispherical.

4. An apparatus as in claim 2, wherein the cavity is substantially cylindrical.

5. An apparatus as in claim 1, further comprising a baffle dividing the region between the mask and the optical area into a plurality of sections, wherein the electromagnetic transducer comprises a plurality of electromagnetic sensors each responsive to radiation in the distinct one of the sections.

6. An apparatus as in claim 5, further comprising a second plurality of sensors each responsive to radiation in a distinct one of the sections, wherein each plurality of sensors is responsive to a different type of radiation.

7. An apparatus as in claim 6, wherein the different types of radiation differ in wavelength.

8. An apparatus as in claim 6, wherein the different types of radiation comprise radiation pulsing at different rates.

9. An apparatus as in claim 1, further comprising a baffle dividing the region between the mask and the optical area into a plurality of sections, wherein the electromagnetic transducer comprises a plurality emitters each emitting radiation through a distinct one of the sections.

10. An apparatus as in claim 9, further comprising a second plurality of emitters each emitting radiation through a distinct one of the sections, wherein each plurality of emitter emits a different type of radiation.

11. An apparatus as in claim 10, wherein the different types of radiation differ in wavelength.

12. An apparatus as in claim 10, wherein the different types of radiation comprise radiation pulsing at different rates.

13. An apparatus as in claim 1, further comprising a light deflector positioned between the mask and the optical area.

14. An apparatus as in claim 13, wherein the light deflector comprises a diffusely reflective cone.

15. An apparatus as in claim 13, wherein the light deflector comprises a baffle.

16. An apparatus as in claims 2, wherein the electromagnetic transducer emits light into the cavity.

17. An apparatus as in claim 16, wherein the electromagnetic transducer emits light into the cavity from a location on a surface of the mask facing the aperture of the cavity.

18. An apparatus as in claim 16, wherein the electromagnetic transducer emits light into the cavity from a point on a wall of the cavity.

19. An apparatus as in claim 2, wherein the electromagnetic transducer detects light in the cavity.

20. An apparatus as in claim 19, wherein the electromagnetic transducer detects light reflected from the cavity to a location on a surface of the mask facing the aperture of the cavity.

21. An apparatus as in claim 19, wherein the electromagnetic transducer detects light incident on a point on a wall of the cavity.

22. An apparatus as in claim 1, wherein a surface of the mask facing the optical area is diffusely reflective.

23. An apparatus as in claim 1, wherein:

the electromagnetic transducer comprises an optical emitter for radiating light in response to the electrical signals; and

the mask intercepts a portion of the light radiating from the emitter, such that the apparatus substantially uniformly illuminates a range of azimuths and elevations of a hemispherical region above the horizon district.

24. An apparatus as in claim 23, wherein a surface of the mask facing the optical area is diffusely reflective.

25. An apparatus as in claim 1, wherein:

the electromagnetic transducer comprises an optical sensor for generating the electrical signals in response to incident light detected by the optical sensor; and

the mask intercepts a portion of incident light from the optical area and the sensor, such that the apparatus has a substantially uniform sensitivity to light incident from a range of azimuths and elevations of a hemispherical region above the horizon district.

26. An apparatus as in claim 25, wherein a surface of the mask facing the optical area is diffusely reflective.