LIGHT GUIDE, LIGHT SOURCE DEVICE, AND IMAGE READING DEVICE

• US 20180203178A1
• Filed: 03/14/2018
• Published: 07/19/2018
• Est. Priority Date: 12/20/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: FUJIUCHI, Akiko, ARIMOTO, Hironobu, MATSUZAWA, Taku
• Granted Patent: US 10,162,096 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 19/0047 for use with a light source G02B19/009, G02B19/0095 take precedence; details of lighting devices in general F21V; non-semiconductor lasers having optical devices external to the laser cavity H01S3/005
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G02B 3/02 with non-spherical faces G02B3/10 takes precedence
• CPC Class Codes: G02B 6/0045 by shaping at least a portion of the light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G03B 15/03 Combinations of cameras with lighting apparatus; Flash units
• 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 1/0284 in combination with a light integrating, concentrating or diffusing cavity
• CPC Class Codes: H04N 2201/0081 Image reader H04N2201/0091 - H04N2201/0094 take precedence

Abstract

A light guide includes a first exit portion emitting first exiting light, a second exit portion emitting second exiting light in a different direction than the first exiting light, and a reflecting portion reflecting light entering the light guide to each of the first and second exit portions. The first and second exit portions respectively have first and second curved surfaces each having a convex cross section perpendicular to the long axis direction. The second exit portion is connected to the first exit portion in the direction perpendicular to the long axis direction. The reflecting portion is provided, in a plane facing the first exit portion and the second exit portion, at a position shifted in the direction perpendicular to the long axis direction from a position where a normal to the plane passes through a connection portion between the first and second exit portions.

Claims

1. (canceled)

2. An image reading device comprising two light guide assemblies, a first unit and a second unit, each including (i) a light guide extending in a long axis direction and having an end in the long axis direction from which light enters the light guide and (ii) a housing retaining the light guide, the first unit and the second unit being on opposing sides of an object to be irradiated with the light from the light guide,

wherein

the light guide comprises:

a first exit portion having a first curved surface having a convex cross section perpendicular to the long axis direction, and emitting first exiting light;

a second exit portion having a second curved surface having a convex cross section perpendicular to the long axis direction, being connected to the first exit portion in a direction perpendicular to the long axis direction, and emitting second exiting light in a direction different from a direction of the first exiting light;

a first reflecting portion disposed in a plane portion facing the first exit portion; and

a second reflecting portion disposed in a plane portion facing the second exit portion, the second reflecting portion having an area smaller than an area of the first reflecting portion,

the second exiting light irradiates an area different from an area of the object to be irradiated with the first exiting light,

the housing retains imaging optical system to focus scattered light, the scattered light being the second exiting light, from the light guide, that is reflected on the object to be irradiated, and

the first exiting light emitted from the first unit enters the imaging optical system of the second unit, and the first exiting light emitted from the second unit enters the imaging optical system of the first unit.

3. The image reading device according to claim 2, wherein an optical axis of the first exiting light and an optical axis of the second exiting light intersect with each other.

4. The image reading device according to claim 2, wherein the first curved surface and the second curved surface have a same curvature.

5. The image reading device according to claim 2, wherein the first curved surface and the second curved surface form a continuous surface.

6. The image reading device according to claim 2, wherein

the first curved surface and the second curved surface form a continuous surface, and

the light guide forms, in a cross section perpendicular to the long axis direction, a shape obtained by connecting straight lines to the first curved surface and the second curved surface.

7. The image reading device according to claim 2, wherein the plane portion facing the first exit portion and the plane portion facing the second exit portion form, in a cross section perpendicular to the long axis direction, a shape obtained by connecting straight lines.

8. The image reading device according to claim 2, the plane portion facing the first exit portion and the plane portion facing the second exit portion have normals pointing in different directions.

9. The image reading device according to claim 2, further comprising a second light guide being retained in the housing, extending in the long axis direction and having an end in the long axis direction from which light enters the second light guide,

wherein

the second light guide comprises a third exit portion emitting third exiting light, and a third reflecting portion disposed in a plane portion facing the third exit portion,

the second exiting light and the third exiting light irradiate an area different from an area of the object to be irradiated with the first exiting light,

the imaging optical system is disposed between the light guide and the second light guide, and

the housing retains the imaging optical system to focus scattered light, the scattered light being (i) the second exiting light, from the light guide, that is reflected on the object to be irradiated and (ii) the third exiting light, from the second light guide, that is reflected on the object to be irradiated.

10. An image reading device comprising two light guide assemblies, a first unit and a second unit, each including (i) a light guide extending in a long axis direction and having an end in the long axis direction from which light enters the light guide and (ii) a housing retaining the light guide, the first unit and the second unit being on opposing sides of an object to be irradiated with the light from the light guide,

wherein

the light guide comprises:

a first exit portion having a first curved surface having a convex cross section perpendicular to the long axis direction, and emitting first exiting light;

a second exit portion having a second curved surface having a convex cross section perpendicular to the long axis direction, being connected to the first exit portion in a direction perpendicular to the long axis direction, and emitting second exiting light in a direction different from a direction of the first exiting light;

a first reflecting portion disposed in a plane portion facing the first exit portion; and

a second reflecting portion disposed in a plane portion facing the second exit portion,

the second exiting light irradiates an area different from an area of the object to be irradiated with the first exiting light,

the housing retains imaging optical system to focus scattered light, the scattered light being the second exiting light, from the light guide, that is reflected on the object to be irradiated, and

the first exiting light emitted from the first unit enters the imaging optical system of the second unit, and the first exiting light emitted from the second unit enters the imaging optical system of the first unit.

11. The image reading device according to claim 10, wherein

the plane portion facing the first exit portion and the plane portion facing the second exit portion have normals pointing in different directions, and

the plane portion facing the first exit portion and the plane portion facing the second exit portion form, in a cross section perpendicular to the long axis direction, a shape obtained by connecting straight lines.