Color image reading apparatus with volume hologram

• US 5,329,384 A
• Filed: 04/05/1993
• Issued: 07/12/1994
• Est. Priority Date: 10/26/1990
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Taniguchi, Naosato, Setani, Michitaka
• Primary Examiner(s): BRINICH, STEPHEN M
• Application Number:
  US08/043,582
• Time in Patent Office: 463 Days
• Field of Search: 358/55, 358/494, 358/513-514, 359/15, 359/30, 359/558, 359/866
• US Class Current: 358/514
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: H04N 1/488 using beam-splitters
• CPC Class Codes: H04N 23/16 Optical arrangements associated therewith, e.g. for beam-splitting or for colour correction

Abstract

A color image reading apparatus includes a plurality of line sensors formed by arranging a plurality of one-dimensional sensor arrays on a single substrate, a focusing optical system for focusing an object on the sensors, and a volume hologram, arranged in the optical path between the focusing optical system and the sensors, for color-separating light from the object into a plurality of color components and guiding the plurality of color components to the corresponding one-dimensional sensor arrays.

Claims

1. A color image reading apparatus comprising:

a plurality of line sensors formed by arranging a plurality of one-dimensional sensor arrays on a single substrate;

a focusing optical system for focusing an object on said sensors; and

a volume hologram, arranged in an optical path between said focusing optical system and said sensors, for color-separating light from the object into a plurality of color components and guiding the plurality of color components to corresponding ones of said one-dimensional sensor arrays.

2. An apparatus according to claim 1, wherein said volume hologram color-separates an incident light beam into a red light component, a green light component, and a blue light component, the green and blue light components having principal wavelengths satisfying a Bragg diffraction condition.

3. An apparatus according to claim 1, wherein the volume hologram is formed by multiple exposures.

4. An apparatus according to claim 1, wherein the volume hologram color-separates an incident light beam into a red light component, a green light component, and a blue light component, at least two of the color light components having principal wavelengths satisfying a Bragg diffraction condition.

5. An apparatus according to claim 1, wherein the focusing optical system is an exit type telecentric system.

6. An apparatus according to claim 1, wherein the volume hologram is a reflection type.

7. An apparatus according to claim 1, wherein the plurality of line sensors are arranged at an equal distance between the respective sensor arrays.

8. A color image reading apparatus comprising:

a plurality of line sensors formed by arranging a plurality of one-dimensional sensor arrays;

a focusing optical system for focusing an object on the sensors; and

a volume hologram arranged in an optical path between the focusing optical system and the sensors, for color separating light from the object into a plurality of color components corresponding to ones of the one-dimensional sensor arrays.

9. An apparatus according to claim 8, wherein the volume hologram color-separates an incident light beam into a red light component, a green light component, and a blue light component, the green and blue light components having principal wavelengths satisfying a Bragg diffraction condition.

10. An apparatus according to claim 8, wherein the volume hologram is formed by multiple exposures.

11. An apparatus according to claim 8, wherein the volume hologram color-separates an incident light beam into a red light component, a green light component, and a blue light component, at least two of the color light components having principal wavelengths satisfying a Bragg diffraction condition.

12. An apparatus according to claim 8, wherein the focusing optical system is an exit type telecentric system.

13. An apparatus according to claim 8, wherein the volume hologram is a reflection type.

14. An apparatus according to claim 8, wherein the plurality of line sensors are arranged at an equal distance between the respective sensor arrays.