IMAGE SENSING APPARATUS

• US 20090147321A1
• Filed: 10/30/2008
• Published: 06/11/2009
• Est. Priority Date: 12/06/2007
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: MINOBE, Tadashi, Kawano, Hiroyuki, Mikami, Izumi, Endo, Takafumi
• Granted Patent: US 7,884,976 B2
• Time in Patent Office: Days
• US Class Current: 358/475
• 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 1/02835 in combination with a light guide, e.g. optical fibre, glass plate light-guides per se G02B6/00
• CPC Class Codes: H04N 1/0318 Integral pick-up heads, i.e. self-contained heads whose basic elements are a light-source, a lens array and a photodetector array which are supported by a single-piece frame
• CPC Class Codes: H04N 1/1017 the main-scanning components remaining positionally invariant with respect to one another in the sub-scanning direction
• CPC Class Codes: H04N 1/193 using electrically scanned linear arrays , e.g. linear CCD arrays
• CPC Class Codes: H04N 2201/03112 Light source
• CPC Class Codes: H04N 2201/03129 Transparent cover or transparent document support mounted on the head
• CPC Class Codes: H04N 2201/03137 Reflecting element downstream of the scanned picture elements
• CPC Class Codes: H04N 2201/03145 Photodetector

Abstract

An image sensing apparatus having a large depth of focus (DOF) and being compact in size is provided. The image sensing apparatus includes a plurality of light sources that shines light beams on an illumination portion of a document; a first mirror that receives incident light scattered by reflection from the document, to reflect the scattered light in the secondary scan direction; a plurality of first concaved aspheric mirrors that collimates light beams from the first mirror, to reflect therefrom the collimated light beams as substantially collimated light fluxes; an aperture mirror that reflects therefrom the light beams from the respective first aspheric mirrors, through apertures each having a light-shielded portion formed therearound and selectively passing the light beams therethrough; a plurality of second concaved aspheric mirrors that receives the light beams incident from the respective aperture mirror, to reflect the incident light beams as converging light beams; a second mirror that reflects the light beams in a direction perpendicular to the surface of the document, disposed on a path of the light beams to be converged by means of the second aspheric mirrors; a plurality of light receivers each having a light-receiving area that receives the light beams from the second mirrors, to form images according to the light beams from the respective apertures; and a casing where the first and second aspheric mirrors are disposed on a first side of the casing in the secondary scan direction, and the aperture mirror is disposed on a second side thereof in the secondary scan direction.

Claims

1. An image sensing apparatus, comprising:

a light source that shines light on an illumination portion of a document across the entire range in a primary scan direction;

a first mirror that receives incident light scattered by reflection from the document, to reflect the scattered light in a secondary scan direction;

a plurality of first concaved aspheric mirrors that collimates light beams from the first mirror, to reflect therefrom the collimated light beams as substantially collimated light fluxes;

an aperture mirror that reflects therefrom the light beams from the first aspheric mirrors, through apertures each having a light-shielded portion formed therearound and selectively passing the light beams therethrough;

a plurality of second concaved aspheric mirrors that receives light beams incident from the aperture mirror, to reflect the incident light beams as converging light beams;

a second mirror that reflects the light beams in a direction perpendicular to the surface of the document, disposed on a path of the light beams to be converged by means of the respective second aspheric mirrors;

a plurality of light receivers each having a light-receiving area where the light beams from the second mirrors are incident, and images are thereby formed according to the light beams from the respective apertures; and

a casing where at least the first and second aspheric mirrors are disposed on a first side of the casing in the secondary scan direction and the aperture mirror is disposed on a second side thereof in the secondary scan direction.

3. The image sensing apparatus of claim 1, wherein the aperture mirror is located at focal point of the respective first aspheric mirrors.

4. The image sensing apparatus of claim 1, wherein the aperture mirror is located at focal point of the respective second aspheric mirrors.

5. The image sensing apparatus of claim 1, wherein the first aspheric mirrors are integral with the second aspheric mirrors, and the first ones are located to the side of the illumination portion and the second ones to the side of the light receiver.

6. The image sensing apparatus of claim 1, wherein a plurality of light shields that each prevents leak light incident on any one of the second aspheric mirrors arranged in an array from its neighboring mirrors is provided in boundary regions of the mirrors.

7. The image sensing apparatus of claim 6, wherein each of the light shields has an uneven surface.

8. The image sensing apparatus of claim 1, wherein the first and second mirrors are disposed in a plane normal to a carriage plane of an illuminated object.

2. An image sensing apparatus, comprising:

a light source that shines light on an illumination portion of a document across the entire range in a primary scan direction;

a first mirror that receives incident light scattered by reflection from the document, to reflect the scattered light in a secondary scan direction;

a plurality of first concaved aspheric mirrors that collimates the light beams from the first mirror, to reflect therefrom the collimated light beams as substantially collimated light fluxes;

an aperture mirror that reflects therefrom the light beams from the first aspheric mirrors, through apertures each having a light-shielded portion formed therearound and selectively passing the light beams therethrough;

a plurality of second concaved aspheric mirrors that receives the light beams incident from the aperture mirror, to reflect the incident light beams as converging light beams;

a second mirror that reflects the light beams in a direction perpendicular to the surface of the document, disposed on a path of the light beams to be converged by means of the respective second aspheric mirrors;

a plurality of light receivers each having a light-receiving area where the light beams from the second mirrors are incident and images are thereby formed according to the light beams from the respective apertures; and

a casing where at least the first and second aspheric mirrors are arranged in respective arrays on a first side of the casing in the secondary scan direction, along the primary scan direction and the apertures and the aperture mirror is arranged in respective arrays on a second side thereof in the secondary scan direction, therealong.

9. An image sensing apparatus, comprising:

an RGB light source that shines light on an illumination portion of a document across the entire range in a primary scan direction;

a first mirror that receives incident light scattered by reflection from the document, to reflect the scattered light in a secondary scan direction;

a plurality of first concaved aspheric mirrors that collimates light beams from the first mirror, to reflect therefrom the collimated light beams as substantially collimated light fluxes;

an aperture mirror that reflects therefrom the light beams from the first aspheric mirrors, through apertures each having a light-shielded portion formed therearound and selectively passing the light beams therethrough;

a plurality of second concaved aspheric mirrors that receives light beams incident from the aperture mirror, to reflect the incident light beams as converging light beams;

a second mirror that reflects the light beams in a direction perpendicular to the surface of the document, disposed on a path of the light beams to be converged by means of the respective second aspheric mirrors;

a plurality of light receivers each having RGB filters corresponding to the respective optical wavelengths of the RGB light beams in a light-receiving area where the light beams from the second mirrors are incident and images are thereby formed according to the light beams from the respective apertures; and

a casing where at least the first and second aspheric mirrors are disposed on a first side of the casing in the secondary scan direction and the aperture mirror is disposed on a second side thereof in the secondary scan direction;

10. An image sensing apparatus, comprising:

an RGB light source that shines light on an illumination portion of a document across the entire range in a primary scan direction;

a first mirror that receives incident light scattered by reflection from the document, to reflect the scattered light in a secondary scan direction;

a plurality of first concaved aspheric mirrors that collimates light beams from the first mirror, to reflect therefrom the collimated light beams as substantially collimated light fluxes;

an aperture mirror that reflects therefrom the light beams from the first aspheric mirrors, through apertures each having a light-shielded portion formed therearound and selectively passing the light beams therethrough;

a plurality of second concaved aspheric mirrors that receives light beams incident from the aperture mirror, to reflect the incident light beams as converging light beams;

a second mirror that reflects the light beams in a direction perpendicular to the surface of the document, disposed on a path of the light beams to be converged by means of the respective second aspheric mirrors;

a plurality of light receivers each having RGB filters corresponding to the respective optical wavelengths of the RGB light beams in a light-receiving area where the light beams from the second mirrors are incident and images are thereby formed according to the light beams from the respective apertures; and

a casing where at least the first and second aspheric mirrors are arranged in respective arrays on a first side of the casing in the secondary scan direction, along the primary scan direction and the apertures and the aperture mirror are arranged in an array on a second side thereof in the secondary scan direction, therealong.

11. The image sensing apparatus of claim 10, wherein a plurality of light shields that each prevents leak light incident on any one of the second aspheric mirrors arranged in an array from its neighboring mirrors is provided in boundary regions of the mirrors.

12. The image sensing apparatus of claim 11, wherein each of the light shields has an uneven surface.

13. An image sensing apparatus, comprising:

a fluorescent light source that shines fluorescent light on an illumination portion of a document across the entire range in a primary scan direction;

a first mirror that receives incident light scattered by reflection from the document, to reflect the scattered light in a secondary scan direction;

a plurality of first concaved aspheric mirrors that collimates light beams from the first mirror, to reflect therefrom the collimated light beams as substantially collimated light fluxes;

an aperture mirror that reflects therefrom the light beams from the first aspheric mirrors, through apertures each having a light-shielded portion formed therearound and selectively passing the light beams therethrough;

a plurality of second concaved aspheric mirrors that receives the light beams incident from the aperture mirror, to reflect the incident light beams as converging light beams;

a second mirror that reflects the light beams in a direction perpendicular to the surface of the document, disposed on a path of the light beams to be converged by means of the respective second aspheric mirrors;

a plurality of light receivers that includes filters of a plurality of different light colors each having a wavelength longer than that of the blue light, in a light-receiving area where the light beams from the second mirrors are incident and images are thereby formed according to the light beams from the respective apertures;

a casing where at least the first and second aspheric mirrors are disposed on a first side of the casing in the secondary scan direction and the aperture mirror is disposed on a second side thereof in the secondary scan direction; and

a low-cut filter that cuts off light of wavelengths shorter than that of blue light, provided in the path of the light passing from the fluorescent light source to the document.

14. An image sensing apparatus, comprising:

a fluorescent light source that shines fluorescent light on an illumination portion of a document across the entire range in a primary scan direction;

a first mirror that receives incident light scattered by reflection from the document, to reflect the scattered light in a secondary scan direction;

a plurality of first concaved aspheric mirrors that collimates light beams from the first mirror, to reflect therefrom the collimated light beams as substantially collimated light fluxes;

an aperture mirror that reflects therefrom the light beams from the first aspheric mirrors, through apertures each having a light-shielded portion formed therearound and selectively passing the light beams therethrough;

a plurality of second concaved aspheric mirrors that receives the light beams incident from the aperture mirror, to reflect the incident the light beams as converging light beams;

a second mirror that reflects the light beams in a direction perpendicular to the surface of the document, disposed on a path of the light beams to be converged by means of the respective second aspheric mirrors;

a plurality of light receivers that includes filters of a plurality of different light colors each having a wavelength longer than that of the blue light, in a light-receiving area where the light beams from the second mirrors are incident, and images are thereby formed according to the light beams from the respective apertures;

a casing where at least the first and second aspheric mirrors are arranged in respective arrays on a first side of the casing in the secondary scan direction, along the primary scan direction and the apertures and the aperture mirror are arranged in respective arrays on a second side thereof in the secondary scan direction, therealong; and

a low-cut filter that cuts off light of wavelengths shorter than that of blue light, provided in the path of the light passing from the fluorescent light source to the document.

15. The image sensing apparatus of claim 14, wherein a plurality of light shields that each prevents leak light incident on any one of the second aspheric mirrors arranged in an array from its neighboring mirrors is provided in boundary regions of the mirrors.

16. The image sensing apparatus of claim 15, wherein each of the light shields has an uneven surface.