Irradiation device and image-reading device

Patent metadata

Field	Value
Publication number	US-9329333-B2
Application number	US-201214371079-A
Country	US
Kind code	B2
Filing date	Dec 3, 2012
Priority date	Jan 30, 2012
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

An irradiation device increasing the lighting depth and facilitating the assembling is provided. A transparent bar-shaped light guide having LEDs disposed near ends thereof includes a first prism group and a first reflector, and, a second prism group and a reflector which are provided so as to extend in a lengthwise direction and which diffuse and reflect light. The light guide includes a first light outgoing area emitting reflected light as primary light Lm, and a second light outgoing area emitting reflected light as secondary light Ls. The first light outgoing area includes a plane portion forming a flat surface. A plane mirror reflects the secondary light Ls in a direction overlapping the primary light Lm in a read area.

First claim

The invention claimed is:

1. An irradiation device comprising:
a light source that emits light;
a transparent bar-shaped light guide having a circular cross section with radius R and the light source disposed near an end of the light guide;
a first diffusion/reflection portion which is provided so as to extend in a lengthwise direction of the light guide, and which diffuses and reflects light propagating in an interior of the light guide;
a first light outgoing area which is a portion of an outer surface of the light guide extending in the lengthwise direction and located in a reflection direction of the first diffusion/reflection portion, and which emits, as primary light, light reflected by the first diffusion/reflection portion;
a second diffusion/reflection portion which is provided so as to extend in the lengthwise direction of the light guide, and which diffuses and reflects light propagating in the interior of the light guide;
a second light outgoing area which is a portion of the outer surface of the light guide extending in the lengthwise direction and located in a reflection direction of the second diffusion/reflection portion, and which emits, as secondary light, light reflected by the second diffusion/reflection portion;
a plane mirror that reflects the secondary light in a direction overlapping the primary light in a predetermined area;
the second light outgoing area having a curvature of 1/R as viewed in the lengthwise direction of the light guide;
the first light outgoing area that at least partially includes a curved portion having a curvature that is less than 1/R as viewed in the lengthwise direction; and
the primary light having a wider divergence angle than that of the secondary light.

2. The irradiation device according to claim 1 , wherein either one of or both of the first diffusion/reflection portion and the second diffusion/reflection portion comprise a prism group provided in an area extending in the lengthwise direction of the light guide.

3. The irradiation device according to claim 2 , wherein:
both of the first diffusion/reflection portion and the second diffusion/reflection portion comprise the respective prism groups; and
a number of prisms included in the prism group of the second diffusion/reflection portion is larger than a number of prisms included in the prism group of the first diffusion/reflection portion.

4. The irradiation device according to claim 2 , wherein either one of or both of the first diffusion/reflection portion and the second diffusion/reflection portion comprising the prism group further comprise a reflector that covers the prism group.

5. The irradiation device according to claim 4 , wherein:
both of the first diffusion/reflection portion and the second diffusion/reflection portion comprise the respective reflectors; and
the reflectors are integral and cover both prism groups.

6. The irradiation device according to claim 2 , wherein either one of or both of the first diffusion/reflection portion and the second diffusion/reflection portion comprising the prism group further comprise a reflection/scattering substance layer containing reflection/scattering substances on an outer surface of the prism group.

7. The irradiation device according to claim 6 , wherein:
both of the first diffusion/reflection portion and the second diffusion/reflection portion comprise the respective reflection/scattering substance layers; and
an amount of reflection/scattering substances contained in the reflection/scattering substance layer of the second diffusion/reflection portion is larger than an amount of reflection/scattering substances contained in the reflection/scattering substance layer of the first diffusion/reflection portion.

8. The irradiation device according to claim 1 , wherein the first diffusion/reflection portion and the second diffusion/reflection portion are each a reflection/scattering substance layer which is provided in an area in the outer surface of the light guide extending in the lengthwise direction and which contains a reflection/scattering substance.

9. The irradiation device according to claim 8 , wherein an amount of reflection/scattering substances forming the second diffusion/reflection portion is larger than an amount of reflection/scattering substances forming the first diffusion/reflection portion.

10. An image-reading device comprising:
irradiation device according to claim 1 ; and
a reader device that receives light reflected from an object irradiated with light from the irradiation device to output image data.

11. The irradiation device according to claim 1 , wherein the first light outgoing area includes a plane.

12. The irradiation device according to claim 11 , wherein the curved portion includes a first circumference portion arranged at a first edge of the plane and a second circumference portion arranged at a second edge of the plane.

13. An irradiation device comprising:
a light source that emits light;
a transparent bar-shape light guide having the light source disposed near an end of the light guide;
a first diffusion/reflection portion which is provided so as to extend in a lengthwise direction of the light guide, and which diffuses and reflects light propagating in an interior of the light guide;
a first light outgoing area which is a portion of an outer surface of the light guide extending in the lengthwise direction and located in a reflection direction of the first diffusion/reflection portion, and which emits, as primary light, light reflected by the first diffusion/reflection portion;
a second diffusion/reflection portion which is provided so as to extend in the lengthwise direction of the light guide, and which diffuses and reflects light propagating in the interior of the light guide;
a second light outgoing area which is a portion of the outer surface of the light guide extending in the lengthwise direction and located in a reflection direction of the second diffusion/reflection portion, and which emits, as secondary light, light reflected by the second diffusion/reflection portion:
a plane minor that reflects the secondary light in a direction overlapping the primary light in a predetermined area,
wherein:
the second light outgoing area has a curvature as viewed in the lengthwise direction of the light guide;
the first light outgoing area at least partially includes a plane or a curved face having a smaller curvature than the second light outgoing area as viewed in the lengthwise direction;
the primary light has a wider divergence angle than that of the secondary light,
the light guide comprises a notch which is formed at a portion of the outer surface other than the first light outgoing area and which includes a plane extending in the lengthwise direction;
the irradiation device further comprises a holder that holds the light source and the light guide; and
the holder comprises:
a light-source attachment to which the light source is attached;
an engagement portion which is in communication with a light-source space through which light emitted by the light source passes, and which includes a hole into which an end of the light guide in the lengthwise direction is fitted, thereby being engaged with the end of the light guide;
a first abut portion which is a surface formed on the engagement portion and which abuts the first light outgoing area;
a second abut portion which is a flat surface formed on the engagement portion and which abuts the notch; and
a pushing portion which pushes the end of the light guide in a direction in which, when the end of the light guide is engaged with the engagement portion, the first light outgo

Assignees

• Fujiuchi Akiko
• Shoji Toshiaki
• Kobayashi Nobutaka
• Masuda Akio
• Mitsubishi Electric Corp

Inventors

• Fujiuchi Akiko
• Shoji Toshiaki
• Kobayashi Nobutaka
• Masuda Akio

Classifications

• G02B6/001

  the light being emitted along at least a portion of the lateral surface of the fibre · CPC title

• G02B6/4298

  coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers · CPC title

• G02B6/0085

  Means for removing heat created by the light source from the package · CPC title

• F21Y2115/10

  Light-emitting diodes [LED] · CPC title

• H04N1/02835

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