Light integrating column

• US 7,048,424 B2
• Filed: 08/14/2003
• Issued: 05/23/2006
• Est. Priority Date: 08/14/2002
• Status: Expired due to Fees

• Current Assignee: Cross Match Technologies Incorporated (Assa Abloy AB)
• Original Assignee: Cross Match Technologies Incorporated (Assa Abloy AB)
• Inventors: McClurg, George W, Carver, John F
• Primary Examiner(s): Ward, John Anthony
• Assistant Examiner(s): Tsidulko, Mark
• Application Number:
  US10/640,689
• Publication Number:
  US 20040130908A1
• Time in Patent Office: 1,013 Days
• Field of Search: 362/552, 362/84, 362/268, 362/296, 362/299, 362/302, 362/310, 362/800, 362/252, 356/71
• US Class Current: 362/552
• CPC Class Codes: G02B 5/021 the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
• CPC Class Codes: G02B 5/0284 used in reflection
• CPC Class Codes: G06V 10/145 Illumination specially adapted for pattern recognition, e.g. using gratings
• CPC Class Codes: G06V 40/13 Sensors therefor

Abstract

A light integrating column having an illumination column and windows that allow light to enter and exit the illumination column. The illumination column can be a solid rod or a hollow tube. In an embodiment, the windows are formed at an angle with respect to each other. Light from a light source enters through one of the windows. The light is internally reflected and diffused inside the illumination column. A diffused uniform light is transmitted out through another window. In an embodiment, a reflective coating is applied to a surface of the illumination column.

Claims

1. An apparatus for generating a linear diffused uniform light, comprising:

a solid illumination column comprising a light transmissive material;

a first window in said illumination column for receiving light; and

a second window in said illumination column for transmitting diffused uniform light out of said illumination column,

wherein said second window in said illumination column is placed at an angle with respect to said first window in said illumination column, and

wherein said illumination column internally reflects and diffuses the received light to generate the diffused uniform light, which is transmitted through said second window.

2. The apparatus of claim 1, wherein said linear diffused uniform light illuminates a platen surface in a biometric system.

3. The apparatus of claim 1, wherein said second window in said illumination column is formed at an approximately ninety degree angle with respect to said first window in said illumination column.

4. The apparatus of claim 1, wherein said illumination column is covered with a reflective material.

5. The apparatus of claim 4, wherein said first and second windows are portions of said illumination column that are not covered with said reflective material.

6. The apparatus of claim 1, wherein said first or second windows are areas on a surface of said solid illumination column that are convex relative to the surface of said solid illumination column.

7. The apparatus of claim 1, wherein said first or second windows are areas on a surface of said solid illumination column that are concave relative to the surface of said solid illumination column.

8. The apparatus of claim 1, wherein said first or second windows are areas on a surface of said solid illumination column that are flat relative to the surface of said solid illumination column.

9. The apparatus of claim 1, wherein said material capable of light transmission comprises at least one material of the group consisting of glass, fused silica, and plastic.

10. The apparatus of claim 1, further comprising:

a light source, proximate to said first window, that emits light.

11. The apparatus of claim 10, wherein said light source is aligned with said first window in said illumination column.

12. The apparatus of claim 11, wherein said light source comprises:

an array of light emitting diodes.

13. The apparatus of claim 11, wherein said light source comprises:

a linear light source.

14. A light integrating column for live scanning of a print image on a platen surface, comprising:

a solid illumination column having a first window and a second window; and

a reflective coating on a surface of said solid illumination column,

wherein said reflective coating comprises

a first opening aligned with said first window, and

a second opening aligned with said second window.

15. The diffuser of claim 14, wherein said solid illumination column comprises a light-transparent material.

16. A live scanner, comprising:

a platen surface that receives a print pattern including ridges and valleys; and

a solid light integrating column that generates a diffused, uniform light to illuminate the platen surface,

wherein said integrating column comprises an illumination column having first and second windows.