JPS6347720A - Image reader - Google Patents

Abstract

PURPOSE:To improve resolution and to obtain a sharp image by forming the incident light ends of optical fibers constituting optical fiber flux like concaves and forming outgoing ends of the fibers like convexes. CONSTITUTION:Since the incident light ends 2a of the optical fibers 2 are formed like concaves, light is transmitted to the outside through the outer peripheral walls of the optical fibers by the concave lens effect, so that disturbance due to oblique image light can be reduced. On the other hand, the outgoing ends 2b of the optical fibers 2 are formed like convexes, so that image light beams A, A' transmitted from the incident light ends 2a are converged by the convex lens effect and easily allowed to correspond to respective optical sensors 4a of an optical sensor array 4 and each beam is prevented from being made incident upon the adjacent optical sensor due to diffusion. Thereby, the resolution of an output image can be improved and a sharp image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image reading device installed in equipment such as electronic whiteboards, facsimile machines, and copying machines.

[Prior art]

Conventionally, an optical fiber bundle consisting of a large number of optical fibers is used as an image reading device for electronic whiteboards, etc., and one light input end is made the image reading side, and the other light output end is made to correspond to the optical sensor, so that the image of a microcomputer, etc. can be read. Some are designed to be connected to a processing unit.

However, on the image reading side of this optical fiber bundle, that is, the light input end, not only light from images facing each other enters each optical fiber, but also light from images facing each other into adjacent optical fibers. There is a phenomenon in which light enters the area after being diffused. The image light of such oblique rays is different from the directly facing image and therefore causes disturbance, causing the output image from the light output end of the optical fiber to be blurred and the resolution to be reduced.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading device that uses an optical fiber bundle to improve the resolution and obtain sharp images.

[Structure of the invention]

In order to achieve the above object, an image reading device according to the present invention has a light input end of an optical fiber bundle on the image reading side,
The image reading device is provided with a light sensor element facing the light output end, characterized in that the light input end of the optical fibers constituting the optical fiber bundle is formed into a concave surface, and the light output end is formed into a convex surface.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to embodiments shown in the drawings.

FIG. 2 schematically shows an example of an electronic blackboard using the image reading device of the present invention, and FIG. 1 shows an enlarged view of the main parts of the image reading device.

1 is an optical fiber bundle forming an image reading section, which includes a large number of optical fibers 2.・Constructed by aligning -22. This optical fiber bundle 1 has one end 1
A faces the blackboard 3 to form an image reading side. At its end 1a, there are a number of optical fibers 2. -・、2
The light incident ends 2a, -, -12a are arranged linearly,
The image is read by scanning the blackboard surface. Also, the other end 1b of the optical fiber bundle 1
A photosensor array 4 faces each other. A large number of optical sensors 4a arranged in this optical sensor array 4,
-・-+4a are the light emitting ends 2b, - of a large number of optical fibers 2, -, 2 arranged at the end 1b of the optical fiber.
・.

2b, so that there is a one-to-one correspondence. Further, the light input end 2a of such an optical fiber is formed into a concave surface, and the light output end 2b is formed into a convex surface.

Each optical sensor 4a in the optical sensor array 4 receives light from the light input end 2a of the optical fiber 2, and receives light from the light output end 2b.
It receives the image light emitted from the sensor and converts it into an amount of electricity. The amount of electricity is converted into a digital amount by an A/D converter 5, data processed by a microcomputer 7 via an interface board 6, and outputted from a printer 8 as an output image.

According to the image reading device described above, the image I on the blackboard 3
The image light A that is emitted perpendicularly from the image light A and the image light A'' at an angle close to perpendicular to the light input end 2 of the optical fiber 2 that faces it.
a, and exits from the fiber end 2b while reflecting the outer peripheral surface of the fiber.
transmitted to. However, the image light B diagonally diffused from the image I enters the light input end 2a of the adjacent optical fiber 2.

In this case, in a conventional image reading device, the oblique image light B enters the end face of the adjacent optical fiber 2 and is transmitted to the light output end 2b, but in the device of the present invention, Since the light incident end 2a of 2 is a concave surface, light passes through the outer peripheral wall of the optical fiber 2 and is transmitted to the outside due to the concave lens effect. Therefore, disturbance caused by oblique image light can be reduced.
4. On the other hand, since the light output end 2b of the optical fiber 2 is formed into a convex surface, the image lights A and A' transmitted from the light input end 2a are focused by a convex lens effect, and the optical sensor.
It facilitates correspondence with the individual photosensors 4a of the array 4 and prevents them from entering adjacent photosensors due to diffusion.

Therefore, the image reading device according to the present invention can increase the resolution of an output image and obtain a sharp image.

〔Effect of the invention〕

As described above, according to the present invention, the light input end of the optical fiber constituting the optical fiber bundle is formed into a concave surface, and the light output end is formed into a convex surface, so that a concave lens effect is produced on the image reading side, and a convex lens effect is produced on the image output side. This effect prevents image light from spreading to adjacent optical fibers and optical sensors, resulting in sharper images.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view showing the main parts of an image reading device according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing an example of an electronic whiteboard equipped with the same image reading device. 1... Optical fiber bundle, la, lb... end, 2
...Optical fiber, 2a...Light entrance end, 2b...
- Light output end, 4... Optical sensor array, 4a
...light sensor.

Claims (1)

[Claims] In an image reading device in which an optical fiber bundle is provided with a light input end facing the image reading side and a light sensor element facing the light output end, the light input end of the optical fibers constituting the optical fiber bundle is formed into a concave surface, and the light output end is formed into a convex surface. An image reading device characterized in that it is formed in.