IMAGING OPTICS AND OPTICAL DEVICE FOR MAPPING A CURVED IMAGE FIELD

• US 20130234009A1
• Filed: 07/19/2011
• Published: 09/12/2013
• Est. Priority Date: 07/19/2010
• Status: Active Grant

• Current Assignee: European Space Agency
• Original Assignee: European Space Agency
• Inventors: Guldimann, Benedikt
• Granted Patent: US 9,448,104 B2
• Time in Patent Office: Days
• US Class Current: 250/227.2
• CPC Class Codes: G01J 1/0425 using optical fibers
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0216 using light concentrators or collectors or condensers
• CPC Class Codes: G01J 3/0262 Constructional arrangements for removing stray light
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 6/08 with fibre bundle in form of plate
• CPC Class Codes: G02B 6/10 of the optical waveguide type G02B6/02, G02B6/24 take precedence; devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means G02F1/00; transferring the modulation of modulated light G02F2/00; optical logic elements G02F3/00; optical analogue/digital converters G02F7/00

Abstract

The present invention relates to optical devices for imaging and spectroscopic applications where optical field curvature is a predominant characteristic. In particular, the invention relates to imaging optics and an optical device for mapping a curved image field. The optical device for mapping a curved image field comprises a focal plane array 20 having a plurality of light processing elements 21 and a focal plane adapter 110 mounted in front of the focal plane array 20 configured to transmit the curved image field to the light processing elements 21 of the focal plane array 20. The focal plane adapter 110 comprises a plurality of waveguides 111 wherein first ends of the waveguides 111 facing the incident curved image field are arranged on a curved surface 12, the curved surface 12 being adapted to a profile of an optical field curvature of the curved image field so that the plurality of waveguides 111 divide the curved image field along a curved focal plane of the image field into a plurality of image segments. The second ends of the waveguides 111 are allocated to the light processing elements 21 to map the plurality of image segments onto the allocated light processing elements 21.

Claims

1. An optical device for mapping a curved image field, comprising

a focal plane array (20) having a plurality of light processing elements (21);

and

a focal plane adapter (110;

310;

410) mounted in front of the focal plane array (20) configured to transmit the curved image field to the light processing elements (21) of the focal plane array (20);

characterized in that

the focal plane adapter (110;

310;

410) comprises a plurality of waveguides (111;

311;

411),

wherein first ends of the waveguides (111;

311;

411) facing the incident curved image field are arranged on a curved surface (12), the curved surface (12) being adapted to a profile of an optical field curvature of the curved image field so that the plurality of waveguides (111;

311;

411) divide the curved image field along a curved focal plane of the image field into a plurality of image segments; and

wherein second ends of the waveguides (111;

311;

411) are allocated to light processing elements (21) to map the plurality of image segments onto the allocated light processing elements (21).

2. An optical device according to claim 1, wherein the curved focal surface (12) is an elliptical paraboloid.

3. An optical device according to claim 1, wherein the image segments of the non-planar/curved image plane are mapped onto the allocated light processing elements (21) using specular reflection.

4. An optical device according to at least of one of the claims 1-3, the focal plane adapter being a hollow waveguide array (110).

5. An optical device according to claim 1, the focal plane adapter being an optical waveguide array working on the principle of total internal reflection (310).

6. An optical device according to claims 1 and 5, the optical waveguides (311) being embedded in a substantially transparent material or air/vacuum with a refractive index lower than the refractive index of the waveguides (311) of the focal plane adapter (310), the focal plane adapter (310) having a curved front surface, and wherein the length of the optical waveguides (311) is varying from the inner to the outer portions of the front surface.

7. An optical device according to any of claim 1, 2, 5 or 6 the focal plane adapter (310) being an optical waveguide array working on the principle of total internal reflection, wherein the distance between adjacent waveguides (311) is at least two wavelengths and wherein a front or/and back side of the waveguides comprises an anti-reflective coating.

8. An optical device according to at least one of the preceding claims 1 to 3, the plurality of waveguides (111) having a depth in the range of hundreds of micrometers and comprising walls (14) with a light reflective coating and a thickness of a few micrometers.

9. An optical device according to at least one of the preceding claims, the focal plane array (20) being a planar focal plane array.

10. An optical device according to at least one of the preceding claims, the focal plane array (20) comprising a photo-detector array, or a microlens array, or a liquid crystal array.

11. An optical device according to at least one of the preceding claims, further comprising an isolation layer or gap being arranged between the focal plane adapter (110;

310;

410) and the focal plane array (20).

12. An optical device according to at least one of the preceding claims, the image processing elements (21) of the focal plane array (20) and the plurality of waveguides (111;

311) of the focal plane adapter (110;

310) being arranged in a two-dimensional array.

13. An optical device according to at least one of the preceding claims, the image processing elements (21) of the focal plane array (20) and the plurality of waveguides (411) of the focal plane adapter(410) being arranged in an one-dimensional array.

14. An imaging spectrometer comprising one or several devices according to claim 12 or 13.

15. A spectrometer comprising one or several devices according to claim 12 or 13.

16. A wide field camera comprising one or several devices according to any of the preceding claims 1-13.

17. A telescope comprising one or several devices according to any of the preceding claims 1-13.