LIGHT SOURCE UNIT AND IMAGE READING DEVICE

• US 20140332667A1
• Filed: 12/25/2012
• Published: 11/13/2014
• Est. Priority Date: 12/27/2011
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Hasegawa, Hiroshi, Shoji, Toshiaki, Aramaki, Tohru, Itoh, Atsushi
• Granted Patent: US 9,273,848 B2
• Time in Patent Office: Days
• US Class Current: 250/208.1
• CPC Class Codes: F21V 7/04 Optical design
• CPC Class Codes: G02B 6/0096 the lights guides being of the hollow type
• CPC Class Codes: H04N 1/02825 in combination with at least one reflector which is fixed in relation to the light source H04N1/02835 and H04N1/0284 take precedence
• 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 1/02895 Additional elements in the illumination means or cooperating with the illumination means, e.g. filters H04N1/02885 takes precedence; optical elements other than lenses per se G02B5/00

Abstract

The light source unit comprises a light source emitting visible light and light of a non-visible wavelength; a rod-like light guide at the end of which the light source is provided and within which incident light from the light source is propagated in the long axis direction; a reflector that is linear along the long axis direction and provided on the contour surface of the light guide; and a support member encompassing the reflector and light guide, having a given width in the direction perpendicular to the long axis direction, and provided with an opening extending along the long axis direction. The reflector and support member are formed by a reflecting material containing a substance reflecting the light of a non-visible light wavelength and reflecting the visible light and light of a non-visible light wavelength.

Claims

1. A light source unit, comprising:

a light source emitting visible light and light of a non-visible light wavelength;

a rod-like light guide at the end of which the light source is provided and in which incident light from the light source is propagated in the long axis direction;

a reflector that is linear along the long axis direction and provided on the contour surface of the light guide; and

a reflecting structure encompassing the reflector and the light guide, having a given width in the direction perpendicular to the long axis direction, and provided with an opening extending along the long axis direction,

wherein the reflector and reflecting structure are formed by a reflecting material containing a first reflecting substance that reflects visible light and light of a non-visible light wavelength, having a lower reflectivity for light of non- visible light wavelengths than reflectivity for visible light, and a second reflecting substance having a higher reflectivity for light of a non-visible light wavelength than the first substance.

2. The light source unit according to claim 1, wherein

the reflector is a reflecting layer formed on a part of the contour surface of the light guide.

3. The light source unit according to claim 1, wherein

the reflector is a reflecting prism provided on a part of the contour surface of the light guide.

4. The light source unit according to claim 1, wherein

the second reflecting substance reflects 24% or more of the light of a wavelength of 300 nm or 90% or more of the light of a wavelength of 900 nm.

5. The light source unit according to claim 1, wherein

the second reflecting substance reflects 73% or more of the light of a wavelength of 300 nm or 96% or more of the light of a wavelength of 900 nm.

6. The light source unit according to claim 1, wherein

the reflector is formed by applying the reflecting material or attaching a sheet containing the reflecting material, and

the reflecting structure is formed by applying the reflecting material or attaching a sheet containing the reflecting material.

7. The light source unit according to claim 1, wherein

the second reflecting substance contains at least a metal oxide.

8. The light source unit according to claim 1, wherein

the second reflecting substance contains at least a ceramic.

9. The light source unit according to claim 1, wherein

the light guide has a circular, elliptical, or rectangular cross-section in a place perpendicular to the long axis direction.

10. An image reading device, comprising:

the source unit according to claim 1;

a lens body converging the light emitted by the light source unit and reflected by an irradiated object;

a light receiver receiving the light converged by the lens body; and

an enclosure housing the light source unit, lens body, and light receiver.