Illumination device

• US 20100027254A1
• Filed: 06/10/2009
• Published: 02/04/2010
• Est. Priority Date: 07/29/2008
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Nakayama, Takahiro
• Granted Patent: US 8,419,227 B2
• Time in Patent Office: Days
• US Class Current: 362/235
• 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 1/0285 in combination with at least one reflector which is in fixed relation to the light source
• CPC Class Codes: H04N 1/02865 using an array of light sources or a combination of such arrays, e.g. an LED bar
• CPC Class Codes: H04N 1/03 with photodetectors arranged in a substantially linear array
• CPC Class Codes: H04N 1/0303 with the scanned line and the photodetector array lying in non-parallel planes
• CPC Class Codes: H04N 1/0305 with multiple folds of the optical path
• CPC Class Codes: H04N 1/0311 using an array of elements to project the scanned image elements onto the photodetectors H04N1/0318 takes precedence
• CPC Class Codes: H04N 1/0312 using an array of optical fibres or rod-lenses

Abstract

To provide an illumination device in which a point light source and a reflective member based on a light weight, cheap resin material is used, the illumination device has high precision and is strong to environmental variations when in a state assembled as a unit and is easily moldable as a part, a plurality of point light sources (111) is arrayed, a first reflective member (112b, 112c, 112d) is disposed along an outgoing direction of light of the point light sources, a second reflective member (112e) is disposed in a surface opposed to a light emitting surface of the point light source in an orthogonal direction, the point light sources are moved integrally with a part or a whole of the first and the second reflective member, the illumination device irradiates an irradiation surface by light from the point light sources, rib shaped bodies (112a) are disposed in a light passageway side of the first reflective member, the rib shaped bodies includes a reflective surface and is situated at a position of an approximately equal distance from two adjacent point light sources, the rib shaped bodies are disposed to be approximately orthogonal against a straight line connecting the two adjacent point light sources.

Claims

1. An illumination device that irradiates an irradiation surface by light from a plurality of arrayed point light sources, comprising:

a first reflective member disposed along an outgoing direction of light from the plurality of arrayed point light sources,

a second reflective member disposed opposed to a light emitting surface of the point light sources in an orthogonal direction, wherein

the point light sources and a part or a whole of the first and the second reflective member are moved integrally,

rib shaped bodies including a reflective surface are disposed in a light passageway side of the first reflective member, and

the rib shaped bodies are situated at a position of an approximately equal distance from two adjacent point light sources and are disposed to be approximately orthogonal against a straight line connecting the two adjacent point light sources.

3. The illumination device according to claim 1, wherein

a shortest distance from one of the two adjacent light sources to the reflective surface of the rib shaped bodies is set to L1,

a shortest distance from another of the two adjacent light sources to the reflective surface of the rib shaped bodies is set to L2,

t is set as an average wall thickness of the rib shaped bodies, and

a formula of 0.7<

L1/L2<

1.4 and a formula of 0.05>

t/((L1+L2+t) are established between the L1, the L2 and the t.

5. The illumination device according to claim 1, wherein

the reflective surface of the rib shaped bodies are formed by any surface workings of coating, gold plating and vapor deposition.

6. The illumination device according to claim 1, wherein

an end surface approximately orthogonal to the reflective surface of the rib shaped bodies comes into contact with two or more of the reflective members.

7. The illumination device according to claim 6, wherein

a material that constitutes the rib shaped bodies is made from a plate, and

the plate is different to a part constituting the reflective member coming into contact thereof.

8. The illumination device according to claim 6, wherein

a material that constitutes the rib shaped bodies is made from a glass plate, and

the glass plate is different to a part constituting the reflective member coming into contact thereof.

9. An image reading apparatus in which the illumination device according to claim 1 is used.

2. An illumination device that irradiates an irradiation surface by light from a plurality of arrayed point light sources, comprising:

a third reflective member disposed along an outgoing direction of light from the plurality of arrayed point light sources, wherein

the point light sources and a part or a whole of the third reflective member are moved integrally,

rib shaped bodies including a reflective surface are disposed in a light passageway side of the third reflective member, and

the rib shaped bodies are situated at a position of an approximately equal distance from two adjacent point light sources and are disposed to be approximately orthogonal against a straight line connecting the two adjacent point light sources.

4. The illumination device according to claim 2, wherein

a shortest distance from one of the two adjacent light sources to the reflective surface of the rib shaped bodies is set to L1,

a shortest distance from another of the two adjacent light sources to the reflective surface of the rib shaped bodies is set to L2,

t is set as an average wall thickness of the rib shaped bodies, and

a formula of 0.7<

L1/L2<

1.4 and a formula of 0.05>

t/(L1+L2+t) are established between the L1, the L2 and the t.