Compound curved concentrator based illuminator

• US 20060227393A1
• Filed: 03/31/2005
• Published: 10/12/2006
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Herloski, Robert
• Granted Patent: US 7,593,143 B2
• Time in Patent Office: Days
• US Class Current: 358/509
• CPC Class Codes: H04N 1/02815 Means for illuminating the original, not specific to a particular type of pick-up head
• CPC Class Codes: H04N 1/0284 in combination with a light integrating, concentrating or diffusing cavity
• CPC Class Codes: H04N 1/40056 Circuits for driving or energising particular reading heads or original illumination means H04N1/401, H04N1/407 take precedence

Abstract

A document illuminator comprising a light-transmissive element having nonlinear walls. The walls are shaped in the form of a compound parabolic concentrator with an optically inverted configuration. A diffusive optical source receives light from a side emitting LED embedded therein and redirects it to an aperture along with other light rays that go through total internal reflection from the nonlinear walls. The reflected light rays that are collected at the aperture are in turn transmitted at high power and uniform luminescence to illuminate a document for scanning.

Claims

1. An apparatus comprising

a light-transmissive element having at least one surface;

a cavity formed within said light-transmissive element configured to be capable of retaining a light source;

an aperture formed in said light-transmissive element positioned to receive light emitted from a light source retained in said cavity.

2. An apparatus in accordance with claim 1, wherein said nonlinear surface of said light-transmissive element comprises a parabolic shape.

3. An apparatus in accordance with claim 1, wherein said nonlinear surface of said light-transmissive element terminates at a bottom portion and a top portion.

4. An apparatus in accordance with claim 3, wherein said bottom portion forms an input optical source.

5. An apparatus in accordance with claim 3, wherein said top portion forms an output aperture.

6. An apparatus in accordance with claim 1, wherein said light-transmissive element has a refractive index η

_LTE from about 1.4 to about 1.7.

7. An apparatus in accordance with claim 1, wherein said cavity has a circular cross-section.

8. An apparatus in accordance with claim 1, wherein said light source comprises a side-emitting diode.

9. An apparatus in accordance with claim 1, wherein said light-transmissive element provides total internal reflection of light rays.

10. An apparatus in accordance with claim 1, wherein said light-transmissive element comprises a diffusive surface.

11. An apparatus in accordance with claim 1, wherein light transmitted from the light-transmissive element images a document positioned on a platen.

12. An apparatus in accordance with claim 1, wherein said nonlinear surface of said light-transmissive element envelopes a portion of said light-transmissive element.

13. An apparatus comprising

a platen configured to hold an image and to receive light onto said image;

a compound curved concentrator based light-transmissive element having an aperture, a cavity in said light-transmissive element, a light source embedded in said cavity of said light-transmissive element, a reflector positioned in said light-transmissive-element, wherein light emitted from said light source is internally reflected from said reflector and within said light-transmissive element; and

a photosensitive device positioned and configured with respect to said platen to detect reflected light from said image.

14. An apparatus in accordance with claim 13, wherein said light-transmissive element has a length from about 100 mm to about 400 mm.

15. An apparatus in accordance with claim 13, wherein said light-transmissive element has a height from about 10 mm to about 40 mm.

16. An apparatus in accordance with claim 13, wherein said light-transmissive element has a reflector width about 0.5 mm to about 3 mm, and an aperture width ranging from about 3 mm to about 10 mm.

17. An apparatus in accordance with claim 13, wherein said compound curved concentrator-based light-transmissive element is parabolic, at least at one end.

18. An apparatus in accordance with claim 13, wherein said image is on paper.

19. An apparatus in accordance with claim 13, wherein said photosensitive device comprises charge coupled devices.

20. An apparatus in accordance with claim 13, wherein said apparatus comprises a xerographic device.