IMAGING SYSTEM WITH AN OPTICAL MIRROR ARRANGEMENT AND SELF RIGHTING HOUSING

• US 20100108885A1
• Filed: 03/18/2008
• Published: 05/06/2010
• Est. Priority Date: 03/27/2007
• Status: Active Grant

• Current Assignee: DSAM London LLP
• Original Assignee: DSAM London LLP
• Inventors: Samuelson, David W., Neil, Iain
• Granted Patent: US 8,503,074 B2
• Time in Patent Office: Days
• US Class Current: 250/338.100
• CPC Class Codes: G02B 13/06 Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
• CPC Class Codes: G02B 17/0808 on-axis systems with at least one of the mirrors having a central aperture
• CPC Class Codes: G02B 17/0896 with variable magnification or multiple imaging planes, including multispectral systems systems with only refractive elements G02B15/14

Abstract

A multi-wavelength band imaging system including a beam splitter is provided, allowing image capturing means adapted to specific wavelength bands to be used such as from visible to near infrared, intermediate infrared and far infrared. The system may have a field of view of substantially (360) degrees about an optical axis of the system and may fit into a golf ball sized housing. The imaging system includes a first convex mirror and a second concave mirror. Some embodiments for imaging single or close wavelength bands and not requiring a beam splitter are equally provided. Also provided is a self-righting housing for an imaging system, for example as described above, which self-rights under the action of gravity, thereby disposing the imaging system in an appropriate orientation.

Claims

1. A multi-wavelength band imaging system including

an objective system which is arranged to collect radiation emanating from an object space,

a beam splitter which is arranged to collect radiation from the objective system and to direct collected radiation to first and second image planes, and

first and second image sensors respectively arranged in the first and second image planes;

wherein, the objective system includes a convex reflective surface and a concave reflective surface mutually spaced along an optical axis through the beam splitter, the convex reflective surface being disposed to collect radiation from object space and to deliver the collected radiation to the concave reflective surface, and the concave reflective surface being disposed to transfer radiation collected from the convex reflective surface to the beam splitter past the convex reflective surface; and

wherein the first image sensor is adapted for imaging radiation in a first wavelength band, the second image sensor is adapted for imaging radiation in a second wavelength band, the first and second wavelength bands being either side of a wavelength of about 2.7 microns.

3. A system as claimed in claim 1 including, a positively powered refractive optical component having a useful spectral bandpass in the first and second wavelength bands and being optically between the concave reflective surface and the beam splitter.

4. A system as claimed in claim 1, in which the first wavelength band is from visible to near infrared and the second wavelength band is intermediate infrared, far infrared or both.

5. A system as claimed in claim 1 which has a field of view measured to one side from an optical axis of about 55 degrees.

6. A system as claimed in claim 1 in which the beam splitter comprises ZnS, ZnSe, MgO, sapphire or diamond.

7. A system as claimed in claim 6 in which the positively powered refractive optical component comprises ZnS, ZnSe, MgO, sapphire or diamond.

8. A system as claimed in claim 1, further including a window optically between the object space and the convex reflective surface in which the window has a useful spectral bandpass in the first and second wavelength bands and in which the window comprises ZnS, ZnSe MgO, sapphire or diamond.

12. A system as claimed in claim 1 in which the concave reflective surface is disposed to transfer radiation collected from the convex reflective surface to the beam splitter through an aperture in the convex reflective surface.

13. A system as claimed in claim 12 which has a field of view of about 140 degrees with a 30 degrees axial blindspot viewed along the optical axis.

14. A system as claimed in claim 12 which has a field of view of substantially 360 degrees about the optical axis.

15. A system as claimed in claim 12 in which the convex and concave reflective surfaces and the aperture are shaped and disposed relatively to each other as defined by surfaces 3, 4 and 5, respectively, of table 1 and the appended notes above.

16. A system as claimed in claim 3 and in which the convex and concave reflective surfaces and the aperture are shaped and disposed relatively to each other as defined by surfaces 3, 4 and 5, respectively, of table 1 and the appended notes above in which the positively powered refractive optical component is shaped and disposed relative to the aperture as defined by surfaces 6 and 7 of table 1 and the appended notes above.

17. A system as claimed in claim 16 in which the beam splitter is shaped and disposed relative to the positively powered refractive optical component as defined by surfaces 8,9,10 and 16 in table 1 and the appended notes above.

18. A system as claimed in claim 17 in which the first wavelength band is below about 2.7 micron, the first image plane is disposed within the objective system as defined by surface 15 in table 1 and the appended notes above and the objective system includes refractive optical components as defined by surfaces 11 to 14 in table 1 and the appended notes above between the beam splitter and the first image plane.

19. A system as claimed in claim 17 in which the second wavelength band is above about 2.7 micron, the second image plane is disposed within the objective system as defined by surface 19 in table 1 and the appended notes above and the objective system includes refractive optical components as defined by surfaces 17 and 18 in table 1 and the appended notes above between the beam splitter and the second image plane.

20. A system as claimed in claim 1 in accordance with an optical prescription as defined in table 1 and the appended notes above.

23. A multi wavelength band imaging system including two multi wavelength band imaging systems as claimed in any one of the preceding claims placed back to back to each other in which radiation in a waveband associated with a longer optical path is reflected by the beam splitter and radiation in a waveband associated with a shorter optical path is transmitted by the beam splitter.

31. A multi-wavelength band imaging system as claimed in claim 1 which is housed in a self-righting housing, which is weighted at a bottom end thereof, which defines an outer surface such that the housing rights itself into an upright orientation under the action of gravity and which includes a window to provide a substantially 360 degree field of view about an axis along the upright orientation, wherein the concave reflective surface is secured adjacent a top end opposite the bottom end and the remaining imaging system is secured adjacent the bottom end.

2. (canceled)

9-11. -11. (canceled)

21-22. -22. (canceled)

24-30. -30. (canceled)

32-40. -40. (canceled)

41. An imaging system including:

a first subsystem which includes a first objective system for directing radiation received from a first object space to a first image sensor;

a second subsystem which includes a second objective system for directing radiation from a second object space to a second image sensor;

the first and second optical systems each including a respective first mirror for receiving radiation from the respective object space and directing the radiation to a respective second mirror for directing the radiation to the respective image sensor;

the first and second subsystems being disposed on opposite sides of a plane such that the corresponding first and second object spaces lie on the corresponding side of the plane and each subsystem defining a part spherical field of view extending in directions substantially parallel to the plane.

42. An imaging system as claimed in claim 41 in which the part spherical fields of view combine to form a contiguous field of view without obscurations in the plane at a distance from the optical system of sufficiently low linear resolution.

43-53. -53. (canceled)