Energy transmission

• US 4,240,692 A
• Filed: 12/17/1975
• Issued: 12/23/1980
• Est. Priority Date: 12/17/1975
• Status: Expired due to Term

• Current Assignee: University of Chicago
• Original Assignee: University of Chicago
• Inventors: Winston, Roland
• Primary Examiner(s): Levy, Stewart J.
• Application Number:
  US05/641,557
• Time in Patent Office: 1,833 Days
• Field of Search: 350/96 R, 350/293, 350/294, 350/258, 350/263-265, 126/270, 126/271, 126/438, 126/441, 136/89 PC, 136/206, 237/1 A
• US Class Current: 385/146
• CPC Class Codes: F21V 7/04 Optical design
• CPC Class Codes: F24S 2023/872 Assemblies of spaced reflective elements on common support, e.g. Fresnel reflectors
• CPC Class Codes: F24S 23/00 Arrangements for concentrating solar-rays for solar heat collectors
• CPC Class Codes: F24S 23/70 with reflectors
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0033 characterised by the use
• CPC Class Codes: G02B 19/0042 for use with direct solar radiation
• CPC Class Codes: G02B 2006/12169 Annealing
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• 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
• CPC Class Codes: G02B 6/262 Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements
• CPC Class Codes: G02B 6/42 Coupling light guides with opto-electronic elements
• CPC Class Codes: G02B 6/4203 Optical features
• CPC Class Codes: Y02E 10/44 Heat exchange systems

Abstract

Disclosed are radiant energy transmitting devices operative selectively in concentrative and emissive modes, having transmitting elements including radiant energy transmitting and guiding surfaces at the interface of media of differing indices of refraction for radiant energy. Surfaces generally are of a concavely sloping configuration consistent with reflecting, for example, extremal energy rays entering the element from within a defined field of acceptance at an energy inlet onto an energy trap or, in the alternative, extremal rays from an energy source through an energy outlet within a defined field of emission. The energy source or trap is preferably an energy transducer such as a photoelectric device.

Claims

1. Radiant energy transmission apparatus for use in an external radiant energy transmitting medium and operative in a concentrating mode, said apparatus comprising, transmission means including:

(a) substantially concavely sloping radiant energy reflective wall means for guiding radiant energy, said wall means comprising means defining an energy inlet,

(b) means, including said energy inlet, for defining a field of acceptance for radiant energy, and

(c) a radiant energy refractive internal medium, said reflective wall means comprising an interface between said refractive internal medium and said external radiant energy transmitting medium, and said internal medium having a higher index of refraction for radiant energy then said external medium;

and radiant energy trap means operatively associated with said reflective wall means for receiving radiant energy guided by said wall means;

said concavely sloping reflective wall means having a profile curve sloped to assume the maximum possible slope consistent with totally internally reflecting onto said energy trap means the extremal energy rays which enter said energy inlet within said field of acceptance.

2. Apparatus according to claim 1 wherein said refractive internal medium is of substantially uniform refractive index.

3. Apparatus according to claim 1 wherein the ratio of the refractive index of said internal medium to said external medium is at least the square root of two.

4. Apparatus according to claim 1 wherein said concavely sloping reflective wall means comprise a pair of opposing longitudinally extending, energy reflecting and guiding surface means.

5. Apparatus according to claim 4 wherein said transmission means has an optical axis;

said field of acceptance includes an angular acceptance;

termini of said reflective wall means at said inlet define a longitudinally extending energy inlet having lateral edges;

said energy trap means comprises a longitudinally extending energy outlet substantially co-planar with said energy inlet and having lateral edges;

the profile curve of each said reflecting and guiding surface means is parabolic, having as its parabolic focus an opposing lateral edge of said energy outlet and as its parabolic axis a line forming an angle with said optical axis quantitatively equal to said angular acceptance; and

the field of acceptance of said transmission means, when expressed in terms of optical direction cosines, is an ellipse of semi-minor axis equal to the sine of said angular acceptance and semi-major axis equal to one.

6. Apparatus according to claim 5 wherein the distance separating said energy inlet from said energy outlet is no more than one half the sum of the lateral dimensions of said inlet and outlet multiplied by the cotangent of said angular acceptance.

7. Apparatus according to claim 1 wherein said wall means are substantially conically shaped and define a substantially circular energy inlet and said energy trap means comprises a substantially circular energy outlet which is substantially co-planar with said energy inlet.

8. Apparatus according to claim 7 wherein said transmission means has an optical axis;

said field of acceptance has an angular acceptance;

the profile curve of said reflective wall means is parabolic, having as a parabolic focus an opposing edge of said outlet and having as a parabolic axis a line forming an angle with said optical axis equal to said angular acceptance; and

the field of acceptance of said transmission means, expressed in optical direction cosines is a right circular cone.

9. Apparatus according to claim 1 wherein said energy trap means is external to said transmission means.

10. Apparatus according to claim 1 wherein said energy trap means comprises means for converting radiant energy into electrical energy.

11. Apparatus according to claim 1 further comprising a plurality of said transmission means.

12. Apparatus according to claim 1 wherein said energy inlet is optically coupled with a medium of refractive index identical to the medium external to said transmission means and comprising said reflective wall means.

13. Radiant energy transmission apparatus for use in an external radiant energy transmitting medium and operative in an emitting mode, said apparatus comprising:

transmission means including,

(a) substantially concavely sloping radiant energy reflective wall means for guiding radiant energy, said wall means comprising means defining an energy outlet,

(b) means, including said energy outlet, for defining a field of emission for radiant energy, and

(c) radiant energy refractive internal medium, said reflective wall means comprising an interface between said refractive internal medium and said external radiant energy transmitting medium, and said internal medium having a higher index of refraction for radiant energy than said external medium;

and radiant energy source means operatively associated with said reflective wall means for emitting radiant energy guided by said wall means,

said concavely sloping, reflective wall means including reflective means having a profile curve sloped to assume the maximum possible slope consistent with totally internally reflecting all energy rays from said energy source means through said energy outlet within said field of emission.

14. Apparatus according to claim 13 wherein said refractive internal medium is of substantially uniform refractive index.

15. Apparatus according to claim 13 wherein the ratio of the refractive index of said internal medium to said external medium is at least the square root of two.

16. Apparatus according to claim 13 wherein said concavely sloping reflective wall means comprise a pair of opposing longitudinally extending, energy reflecting and guiding surface means.

17. Apparatus according to claim 16 wherein said transmission means has an optical axis;

said field of emission includes an angular emission;

termini of said reflective wall means at said outlet define a longitudinally extending energy outlet having lateral edges;

said energy source means comprises a longitudinally extending energy source substantially co-planar with said energy outlet and having lateral edges;

the profile curve of each said reflecting and guiding surface means is parabolic, having as its parabolic focus an opposing lateral edge of aid energy inlet and as its parabolic axis a line forming an angle with said optical axis quantitatively equal to said angular emission; and

the field of emission of said transmission means, when expressed in terms of optical direction cosines, is an ellipse of semi-minor axis equal to the sine of said angular emission and semi-major axis equal to one.

18. Apparatus according to claim 17 wherein the distance separating said energy inlet from said energy outlet is no more than one half the sum of the lateral dimensions of said inlet and outlet multiplied by the cotangent of said angular acceptance.

19. Apparatus according to claim 13 wherein said wall means are substantially conically shaped and define a substantially circular energy outlet and wherein said energy trap means comprises a substantially circular energy inlet which is substantially co-planar with said energy outlet.

20. Apparatus according to claim 19 wherein said transmission means has an optical axis;

said field of emission has an angular emission;

the profile curve of said reflective wall means is parabolic, having as a parabolic focus an opposing edge of said inlet and having as a parabolic axis a line forming an angle with said optical axis equal to said angular emission; and

the field of emission of said transmission means, expressed in optical direction cosines is a right circular cone.

21. Apparatus according to claim 13 wherein said energy source means is external to said transmission means.

22. Apparatus according to claim 13 wherein said energy source means comprises means for converting electrical energy into radiant energy.

23. Apparatus according to claim 13 further comprising a plurality of said transmission means.

24. Apparatus according to claim 13 wherein said energy outlet is optically coupled with a medium of refractive index identical to the medium external to said transmission means and comprising said reflective wall means.