Illumination device and image reading device using said illumination device

Patent metadata

Field	Value
Publication number	US-9357095-B2
Application number	US-201314438509-A
Country	US
Kind code	B2
Filing date	Oct 29, 2013
Priority date	Oct 30, 2012
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

Provided are: an illumination device having a configuration in which a temperature rise of a radiation member is suppressed in a limited volume to thereby maintain a temperature of an LED at a predetermined value or less and an image reading device provided with the illumination device. In order to release heat generated by the LED from a substrate on which the LED is mounted, a first heat radiation plate ( 43 ) and a second heat radiation plate ( 47 ) are provided on both sides of the LED-mounted substrate; the second heat radiation plate ( 47 ), the LED-mounted substrate, and the first heat radiation plate ( 43 ) are installed in this order on a second frame ( 40 ) that supports the LED-mounted substrate, first and second heat radiation plates ( 43 ) and ( 47 ); a fan is disposed on the first heat radiation plate ( 43 ) side; when viewing the second frame ( 40 ) in a direction perpendicular to a longitudinal direction thereof, a cross-sectional profile of the second heat radiation plate ( 47 ) has an area protruding with respect to a cross-sectional profile of the first heat radiation plate ( 43 ); and the configuration is such that wind from the fan is aggressively blown against the first and second heat radiation plates ( 43 ) and ( 47 ).

First claim

The invention claimed is:

1. A linear illumination device comprising:
at least one LED used as a light source;
an elongated light guide member that receives light emitted from the light source at an end portion thereof in a longitudinal direction and diffuses the light in a main scan direction;
a frame made of resin;
a fan for suppressing a temperature rise of the LED;
an LED substrate on which the LED is mounted;
a first heat radiation plate that releases heat generated from the LED from a surface of the LED substrate opposite to a surface on which the LED is mounted; and
a second heat radiation plate that releases heat generated from the LED from the surface of the LED substrate on which the LED is mounted, wherein
the second heat radiation plate, the LED substrate, and the first heat radiation plate arc installed in this order on the frame having a support portion supporting the light guide, the LED substrate, the first and second heat radiation plates,
the fan is disposed on a side of the first heat radiation plate opposite to the LED substrate,
the second heat radiation plate has a cross-sectional profile having an area protruding with respect to a cross-sectional profile of the first heat radiation plate when viewing the frame from a direction perpendicular to a longitudinal direction thereof, and
wind from the fan is blown against the first and second heat radiation plates.

2. The linear illumination device according to claim 1 , wherein
the second heat radiation plate is formed into a plate-like shape, and
the protruding area has a shape obtained by bending the plate in a direction toward the first heat radiation plate at a position outside a cross-sectional profile of the LED substrate.

3. The linear illumination device according to claim 2 , wherein
the first heat radiation plate has, on a surface thereof contacting the LED substrate, a plurality of plate-like heat radiation fins extending perpendicular to the surface contacting the LED substrate, and
a leading end of the bent plate of the second heat radiation plate is located at a position exceeding leading ends of the heat radiation fins of the first heat radiation plate.

4. The linear illumination device according to claim 1 , wherein
the fan is a fan and has a duct on a discharge port side of the fan so as to aggressively blow wind generated by the fan against the first and second heat radiation plates.

5. The linear illumination device according to claim 4 , wherein
the second heat radiation plate has a portion obtained by bending the plate in a direction toward the first heat radiation plate at a position outside a cross-sectional profile of the LED substrate, and
a leading end of the bent plate extends in a direction toward the fan beyond a leading end of the duct on the discharge port side.

6. The linear illumination device according to claim 1 , wherein
a plate thickness of the second heat radiation plate is smaller than a plate thickness of the first heat radiation plate that contacts a surface of the LED substrate.

7. The linear illumination device according to claim 1 , further comprising an insulation member between a surface of the LED substrate where the LED is mounted and the second heat radiation plate, and
when viewing the frame from the direction perpendicular to the longitudinal direction thereof, the insulation member has a profile having a size at least equal to or smaller than the cross-sectional profile of the first heat radiation plate.

8. The linear illumination device according to claim 1 , further comprising a heat conductive member that transmits heat generated by the LED from an opposite side of the surface of the LED substrate where the LED is mounted to the first heat radiation plate, and
when viewing the frame from the direction perpendicular to the longitudinal direction thereof, the heat conductive member has a profile having a size at least equal to or smaller than the cross-sectional profile of the first heat radiation plate.

9. An image reading device comprising:
the linear illumination device as claimed in claim 1 ;
a plurality of mirrors that leads light reflected from a document to a predetermined direction for document reading;
a lens that converges the reflected light led by the plurality of mirrors; and
a CCD that photoelectric-converts the light converged by the lens.

Assignees

• Enomoto Shinnosuke
• Nishizawa Seiji
• Hamada Masataka
• Nisca Corp

Inventors

• Enomoto Shinnosuke
• Nishizawa Seiji
• Hamada Masataka

Classifications

• H04N1/02895

  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) · CPC title

• H04N1/00989 Primary

  by natural convection, e.g. using fins without a fan · CPC title

• H04N1/02855 Primary

  in combination with a light guide, e.g. optical fibre, glass plate (light-guides per se G02B6/00) · CPC title

• H04N1/02835

  in combination with a light guide, e.g. optical fibre, glass plate (light-guides per se G02B6/00) · CPC title