Optical throughput condenser

• US 7,192,173 B2
• Filed: 07/18/2003
• Issued: 03/20/2007
• Est. Priority Date: 07/18/2002
• Status: Expired due to Fees

• Current Assignee: Rudolph Technologies Incorporated (Onto Innovation Inc.)
• Original Assignee: Rudolph Technologies Incorporated (Onto Innovation Inc.)
• Inventors: Vaughnn, David
• Primary Examiner(s): Ward; John Anthony
• Application Number:
  US10/622,847
• Publication Number:
  US 20040057135A1
• Time in Patent Office: 1,341 Days
• Field of Search: 362/556, 362/554, 362/558, 359/858
• US Class Current: 362/558
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G02B 5/10 with curved faces

Abstract

An optical throughput condenser re-concentrates light thereby causing light which otherwise would be wasted outside of the useful AΩ product, also known as optical throughput, of an illuminating system to be redirected back into the useful AΩ product. The optical throughput condenser includes a thin film having an angle gate such that light striking the surface with a range of incident angles such that the angle of incident is less than or equal to the gate angle (Θ_GATE) transmits through the thin film. Light striking the surface with a range of incident angles such that the angle of incident is grater than the gate angle. reflects back from the thin film. An integrating sphere is positioned such that light reflecting back from the thin film is directed towards the integrating sphere so that the light is redirected towards the angle gate.

Claims

1. An optical illumination system comprising:

an illuminating source capable of providing light transmissions having a range of angles;

a transmissive substrate positioned in proximity to the illuminating source;

a thin film coating positioned on a surface of the transmissive substrate, the thin film coating having a design property of a distinct cutoff between striking reflected and transmitted light transmissions at a gate angle (Θ

_GATE) such that light transmissions striking the thin film coating at an angle of incidence less than or equal to the gate angle (Θ

_GATE) transmits through the thin film, while light transmissions striking the thin film coating at an angle of incidence greater than the gate angle (Θ

_GATE) reflects back from the thin film; and

an integrating sphere encompassing the thin film coating such that light transmissions reflecting back from the thin film are directed within the integrating sphere and subsequently redirected towards the thin film coating.

2. The optical illumination system of claim 1, wherein a final product of light is generated equaling the combination of all light transmission transmitted through the thin film.

3. The optical illumination system of claim 1, and further comprising:

a plurality of micro retro reflectors positioned on a portion of an inner surface of the integrating sphere.

4. The optical illumination system of claim 3, wherein the plurality of micro retro reflectors are positioned on the portion of the integrating sphere to substantially reverse an incident ray direction of the portion of light transmission reflected back from the thin film.

5. The optical illumination system of claim 1, wherein the illuminating source is positioned within the integrating sphere.

6. The optical illumination system of claim 1, wherein the illuminating source is positioned outside of the integrating sphere and further comprising:

at least one additional illuminating source positioned within the integrating sphere.

7. A method of re-concentrating light within an optical illumination system, comprising:

transmitting a series of light transmission from an illuminating source;

directing the series of light transmission towards a thin film positioned on a surface of a transmissive substrate and having a distinct cutoff between striking reflected and transmitted light transmissions at a gate angle (Θ

_GATE), such that a first portion of the series of light transmissions striking the thin film at an angle of incidence less than or equal to the gate angle (Θ

_GATE) of the thin film transmits through the thin film and the transmissive substrate, And a second portion of the series of light transmissions striking the thin film at an angle of incidence greater than the gate angle (Θ

_GATE) of the thin film reflects back from the thin film;

redirecting the second portion of the series of light transmissions towards the thin film; and

generating a final product of light transmissions equaling all light portions transmitted through the thin film.

8. An apparatus comprising:

an optical source for producing divergent beams;

an integrating sphere for receiving the divergent beams and producing randomly reflected beams; and

a thin film coating coupled to a portion of the integrating sphere for receiving a portion of the randomly reflected beams;

wherein the thin film filter is transmissive for beams having incident angles less than a gate angle of the thin film filter and reflective for beams having incident angles greater than the gate angle of the thin film filter.

9. The apparatus of claim 8, wherein the optical source is located outside the integrating sphere.

10. The apparatus of claim 8, wherein the optical source is located inside the integrating sphere.

11. The apparatus of claim 8, wherein the integrating sphere has a highly randomly reflective interior that includes micro retro reflectors.

12. The apparatus of claim 8, wherein the thin film coating is formed from dielectric materials.

13. The apparatus of claim 8,

wherein an emergent solid angle Ω

is defined as 2π

×

(1-cos [the gate angle]);

wherein an emergent area A is defined as an area of the thin film filter; and

wherein an emergent etendue is defined as A×

Ω

.

14. The apparatus of claim 13,

wherein the optical source has a source etendue;

and

wherein the emergent etendue is less than the source etendue.

15. An apparatus, comprising:

an integrating sphere having a randomly reflective wall surrounding an interior space;

an optical source for introducing light beams into the interior space of the integrating sphere; and

a thin film coating disposed in an aperture of the wall, the thin film filter being transmissive of light beams having an incident angle less than a gate angle of the thin film filter and being reflected of light beams having incident angles greater than the gate angle of the thin film filter.

16. The apparatus of claim 15, wherein the optical source is located outside the integrating sphere.

17. The apparatus of claim 15, wherein the optical source is located inside the integrating sphere.

18. The apparatus of claim 15, wherein the integrating sphere has a highly randomly reflective interior that includes micro retro reflectors.

19. The apparatus of claim 15, wherein the thin film coating is formed from dielectric materials.

20. The apparatus of claim 15,

wherein an emergent solid angle Ω

is defined as 2π

×

(1−

cos [the gate angle]);

wherein an emergent area A is defined as an area of the thin film filter; and

wherein an emergent etendue is defined as A×

Ω

.

21. The apparatus of claim 20,

wherein the optical source has a source etendue;

and

wherein the emergent etendue is less than the source etendue.

22. An apparatus comprising:

an integrating sphere having a highly randomly reflecting interior surface and an output port;

an optical source for introducing light onto the interior surface of the integrating sphere;

a transmissive substrate disposed at the output port of the integrating sphere, having an incident side facing inside of the integrating sphere and an exiting side facing outside the integrating sphere; and

a thin film dielectric coating disposed on the incident side of the transmissive substrate;

wherein the thin film dielectric coating is transmissive for light incident upon the thin film dielectric coating at angles less than a gate angle and reflective for light incident upon the thin film dielectric coating for incident angles greater than the gate angle;

wherein an emergent solid angle Ω

is defined as 2π

×

(1−

cos [the gate angle]);

wherein the transmissive substrate has an emergent area A;

wherein an emergent etendue is defined as A×

Ω

);

wherein the optical source has a source etendue; and

wherein the emergent etendue is less than the source etendue.