JPH03171006A - Image reader - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device, and particularly to an image reading device using an optical waveguide array as a propagation means and a two-dimensional light receiving element as a light receiving means.

[Conventional technology]

Conventionally, an optical fiber array formed from a large number of optical fibers has been used as such an image reading device. Furthermore, a one-dimensional light receiving element has been used as the light receiving means.

That is, to explain with reference to FIG. 5(a), a linear light source 101 is arranged below the original image 102,
01, the original image 102 is irradiated.

The reflected light enters the entrance port 105 of the optical fiber 103, propagates through the optical fiber array 104, and exits from the exit port 107 of the optical fiber array 104. and,
The light is received by the one-dimensional light receiving element 106.

[Problem to be solved by the invention]

However, it is extremely difficult to configure an extremely large number of optical fibers 103 with high precision and at low cost.
Furthermore, in the one-dimensional light-receiving element 106, the number of effective pixels is currently about 10,000 at most, so the reading density is extremely low, making it extremely difficult to read images with high resolution. There is a problem.

For example, 400DPI (dot pe
To obtain r inch) → 乎“×21ξ330
0 pixels are required, and if a higher resolution is required, or a similar resolution is required for a younger or wider object, this is not possible with the conventional one-dimensional light receiving element 106.

The present invention was developed in view of the above problems, and uses an optical waveguide array that has optical waveguide properties equivalent to optical fibers, solves the operational difficulties of bundling optical fibers, and is easier to manufacture. The purpose is to provide an inexpensive and high-density image reading device.

[Means to solve the problem]

The present invention having the above-mentioned object includes a light propagation means comprising a light source that irradiates a document, an optical waveguide array into which light reflected from the document is incident on one end, and an electric signal that receives light emitted from the other end of the propagation means. The optical waveguide array has a one-dimensional array on the document side and a two-dimensional array on the light-receiving means side.

[Effect]

In the image reading device of the present invention having the above configuration, the light reflected from the original by the light source that irradiates the original is incident from the linearly arranged entrance opening of the optical waveguide array serving as the propagation means, and is propagated within the waveguide. The light is emitted from the output ports of the optical waveguide array, which are arranged in a two-dimensional array, and is received by the two-dimensional light-receiving element, which is the light-receiving means, and converted into an electrical signal to read image information. will be held.

〔Example〕

Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. A linear light source 1 is placed below the original image 6. An optical waveguide array 2 is arranged below the original image 6, and the optical waveguide array 2 has the following configuration. Like conventional optical fibers, the optical waveguide array 2 is made of two types of materials with different refractive indexes, and has a cladding 2a with a refractive index n1 and a core 2b with a refractive index n2, and is configured as follows. The relationship is <n2.

Therefore, due to this refractive index relationship, the light beam undergoes almost total reflection at the interface between the core 2b and the cladding, propagates within the core 2b, and exits in a two-dimensional arrangement similar to the linear arrangement of the optical waveguide array 2. 5 emits a light beam. Therefore,
Due to this refractive index relationship, the light beam is almost totally reflected at the interface between the core 2b and the cladding 2a, propagates within the core 2b, and is emitted from the exit port 5 forming a two-dimensional array of optical waveguide arrays 2. . The emitted light beam is a two-dimensional CCD
3, and one line of image information is received. Further, the entrance port 4 slides in the scanning direction A and reading is repeated, thereby reading the entire image.

Here, the configuration of the optical waveguide array 2 will be explained using FIG. 3. This figure shows an example of a method for manufacturing the optical waveguide array 2, which is roughly divided into the following four processes.

(a) (b) (C) Preparation of base film 9: Using methyl acrylate, which is a photosensitizer, with a refractive index n2 = 1.48 as a doping monomer, the refractive index nl = 1.59.
A sheet having a thickness of 50 to 100 μm is formed by melt extrusion (also called casting).

Selective photopolymerization by mask exposure: A mask IO with a pattern such that the portion desired to be an optical waveguide blocks light is placed on the sheet and exposed to ultraviolet rays.

As a result, the methyl acrylate is photopolymerized only in the exposed areas, and the pattern of the mask 10 is transferred.

Removal of unreacted monomer: When the remaining monomer in the unexposed area is removed by vacuum drying, this area becomes
Only the base material is polycarbonate, and the refractive index is 1.5.
This becomes the core portion 2b of No. 9. On the other hand, since the refractive index of the exposed part decreases due to the photopolymerization reaction, this part becomes the cladding part 2.
It becomes a.

(d) Surface cladding: A low refractive index acrylic resin is coated as the cladding layer 2C in the vertical direction of the sheet.

Through the above manufacturing process, an optical waveguide array 2 having a width and a height of approximately several tens of microns is formed.

The characteristics of the leading wavepath are that it is transparent to visible light up to infrared light with a wavelength of around 1.6 μm, and can propagate a multimode light beam with a propagation loss of 0.2 db/aI1. Further, similar effects can be expected for optical waveguide arrays that are not manufactured using such a manufacturing method.

Next, an example of the configuration of the optical waveguide array will be explained with reference to FIG. 4(a) on the side of the output port 5 of the optical waveguide array 2.
Make a cut like this. Then, as shown in FIG. 4(b), by overlapping them sequentially from the end, a linearly arranged one-dimensional entrance port 4 and a two-dimensionally arranged two-dimensional exit port 5 are formed. The two-dimensional configuration of the exit port 5 is not limited to the above example, and may be configured using other methods.

〔Effect of the invention〕

As is clear from the detailed description above, according to the present invention, the propagation means, which was conventionally constructed by bundling a large number of optical fibers, can be constructed with an optical waveguide array, thereby achieving mass production at low cost. Can be done.

In addition, by using a two-dimensional light-receiving element, which has several tens of times as many effective pixels, as the light-receiving means instead of the conventional one-dimensional light-receiving element arranged in a straight line, we have developed a high-performance sensor that enables high-density image reading. A density image reading device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an image reading device of the present invention, FIG. 2 is a schematic configuration diagram showing a cross section of the image reading device, and FIG.
FIG. 3(a) is an explanatory diagram showing a method for manufacturing an optical waveguide array, FIG. 3(a) is an explanatory diagram showing a method for producing a base film, and FIG. 3(b) is an explanatory diagram showing selective photopolymerization by mask exposure. , FIG. 3(C) is an explanatory diagram showing the removal of unreacted monomers, FIG. 3(d) is an explanatory diagram showing the formation of cladding on the surface, and FIG. 4 is an explanatory diagram showing the production of the optical waveguide array of the present invention. An explanatory diagram showing the method, FIG. 5 is a perspective view of a conventional image reading device, FIG. 5(a) is a perspective view of the image reading device, and FIG. 5(b) is a side view of the image reading device. It is a diagram. 1... Light source 2... Optical waveguide array 3... Two-dimensional light receiving element 4... Inlet port 5... Output port 6... Original image

Claims (1)

[Claims] A light propagation means consisting of a light source that illuminates the original, an optical waveguide array into which light reflected from the original enters at one end, and a two-dimensional light receiving element that receives light emitted from the other end of the propagation means and converts it into an electrical signal. What is claimed is: 1. An image reading device comprising a light receiving means, wherein the optical waveguide array is arranged in a one-dimensional arrangement on the document side and arranged in a two-dimensional arrangement on the light receiving means side.