JPH0448863A - Close contact type image sensor - Google Patents

Abstract

PURPOSE:To reduce the deterioration in the resolution even when a gap between a transparent protection layer and an original face by providing a guide path leading a light incident from a light guide window between a sensor glass base and the transparent protection layer to the original face and leading a reflected light from the original face to a photoelectric conversion element to each photoelectric conversion element. CONSTITUTION:A light radiating from a light source 14 radiates an original 19 through a light guide window 13 and a core 20 for each picture element, its reflected light is led to a photoelectric conversion element 11 to obtain electric picture information. In this case, the light radiating the face of the original 19 passes through the core of the guide path, then the dispersion to an adjacent picture element is reduced. Moreover, an incident quantity of a stray light made incident at a larger angle than an aperture angle of the guide path as to the reflected light from the face of the original is reduced by providing a coloring material provided between the guide paths. As a result, crosstalk to an adjacent photoelectric conversion element is reduced and the resolution of the image sensor is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fully contact type image sensor that is an image input device used in facsimile machines, copying machines, image scanners, and the like.

Conventional technology In recent years, linear image sensors used in facsimile machines, copying machines, image scanners, etc. have been divided into three types: a close-contact type that uses a SELFOC lens array as an optical system, a reduction optical type that uses mirrors and lenses, and a reduction optical type that uses no optical system. There are completely contact types, etc. Among these, the demand for fully contact type sensors, which is the most cost-effective method, is increasing mainly in facsimiles.

An example of the conventional complete contact type image sensor mentioned above will be described below with reference to the drawings.

In FIG. 3, 1 is a photoelectric conversion element, 2 is a glass substrate,
3 is a light guide window, 4 is a light source, 5 is a common electrode film, 6 is a-8t
7 is a metal film, 8 is a transparent protective layer, and 9 is an original.

In the contact type image sensor, a transparent protective layer 8 comes into contact with the surface of a document 9 during image reading, and light is irradiated onto the document 9 through a light guide window 3 from a light source 4 provided on the back surface of the sensor. A plurality of light sources 4 are arranged on the center line of the photoelectric conversion element 1 in the main scanning direction, and the light emitted from the light sources 4 is applied to the original 9
By being reflected by the surface and incident on the photoelectric conversion element l, information on the document surface is read.

Problems to be Solved by the Invention However, in a completely contact type image sensor configured as described above, if the gap between the transparent protective layer and the document surface becomes large, the reflected light from the document surface may be transmitted to an adjacent photoelectric conversion element. The problem was that the resolution of the image sensor deteriorated.

In view of the above-mentioned problems, the present invention provides a complete contact type image sensor in which resolution decreases little even when the gap between the transparent protective layer and the document surface becomes large.

Means for Solving the Problems In order to solve the above problems, the present invention provides a glass substrate with a plurality of photoelectric conversion elements provided in the main scanning direction, a light guiding window provided for each photoelectric conversion element, Complete contact type, equipped with a light source that enters illumination light into each light guide window and a transparent protective layer in contact with the document.The light source illuminates the document surface through the light guide window, and the reflected light is read by each photoelectric conversion element. In the image sensor, between the glass substrate and the transparent protective layer,
A core part of the waveguide is provided for each photoelectric conversion element to guide the light incident on the light guide window to the document surface and to guide the reflected light from the document surface to the photoelectric conversion element, and a cladding layer is provided around the core part. The space between the glass substrate and the transparent protective layer other than the waveguide is filled with a colored material.

Effect of the Invention With the above-described configuration, the present invention allows scattering of light emitted from the light guide window toward the document surface to pass through the core portion of the waveguide when the gap between the transparent protective layer and the document surface is large. can be reduced by Furthermore, by providing a colored material in a space other than the waveguide, it is possible to reduce the amount of stray light that is reflected from the document surface and that attempts to enter the waveguide at an angle larger than the aperture angle of the waveguide.

Thereby, the resolution of the image sensor can be improved.

Embodiment A complete contact type image sensor according to an embodiment of the present invention will be described below with reference to one drawing.

In FIGS. 1 and 2, 11 is a photoelectric conversion element;
2 is a glass substrate, 13 is a light guiding window, 14 is a light source, 15 is a common electrode film, 16 is an a-5i film, 17 is a metal film, 18 is a transparent protective layer, 19 is a document, and 20 is a core part of a guiding waveguide. , 21
2 is a curved portion of the waveguide, and 22 is a colored material. A plurality of photoelectric conversion elements 11, light guide windows 13, and core portions 20 are formed in the main scanning direction.

Next, the operation will be explained.

The light emitted from the light source 14 passes through the light guide window 13 and the core section 20 for each pixel and illuminates the surface of the document 19, and the reflected light is guided to the photoelectric conversion element 11, so that electrical image information can be obtained. can. At this time, the light irradiated on the 19th side of the original is
Since the light passes through the core of the waveguide, dispersion to adjacent pixels is reduced. Furthermore, regarding light reflected from the document surface, the amount of stray light that enters at an angle larger than the aperture angle of the waveguide can be reduced by the colored material provided between the waveguides. As a result, crosstalk to adjacent photoelectric conversion elements is reduced, and the resolution of the image sensor is improved. Further, even when the distance between the outer surface of the transparent protective film 18 and the document surface becomes large (approximately 300 μm), good resolution can be maintained.

Note that it is also possible to use a Cd5-CdSe-based thin film as the photoelectric conversion element 11. Further, the transparent protective film 18 can be made of hard coated resin or microsheet glass. It is desirable that the colored material used here has an adhesive function. Also,
The smaller the light transmittance, the better the characteristics.

As described above, according to this embodiment, the sensor glass substrate 12
and the transparent protective layer 18, a core portion of a waveguide that guides light incident from the light guide window 13 to the surface of the original 19 and guides reflected light from the surface of the original 19 to the light source conversion element 11 is provided for each photoelectric conversion element. A cladding layer is provided on the outer periphery of the core portion, and a colored material is provided in the space other than the waveguide between the sensor glass substrate 12 and the transparent protective layer 18, so that the transparent protective film 18
Good resolution can be maintained even if the distance between the outer surface and the surface of the document 19 increases.

Effects of the Invention As described above, the present invention provides a waveguide that guides light incident from a light guide window between a sensor glass substrate and a transparent protective layer to a document surface, and guides reflected light from the document surface to a photoelectric conversion element. is provided for each photoelectric conversion element, it is possible to reduce the scattering of the emitted light, and it is possible to maintain good resolution even if the distance between the outer surface of the transparent protective film and the document surface is large ( can do.

[Brief explanation of the drawing]

FIG. 1 is a sectional view in the sub-scanning direction of a contact type image sensor according to an embodiment of the present invention, FIG. 2 is a sectional view in the main scanning direction, and FIG. 3 is a sectional view of a conventional contact type image sensor. 11...Photoelectric conversion element, 12...Glass substrate, 13...Light guiding window, 14...Light source, 18...Transparent protection Layer, 19... Original, 20... Core part of waveguide, 21...
- Cladding part of waveguide, 22... colored material. Name of agent: Patent attorney Shigetaka Awano

Claims (4)

[Claims] (1) A plurality of photoelectric conversion elements provided in the main scanning direction on a glass substrate, a light guide window provided for each photoelectric conversion element, a light source that supplies illumination light to each light guide window, and a light source that supplies illumination light to each light guide window. In a close-contact image sensor, which is equipped with a transparent protective film layer in contact with the glass substrate, a light source illuminates the document surface through a light guide window, and each photoelectric conversion element reads the reflected light. A waveguide core is provided for each photoelectric conversion element to guide illumination light incident on the light guide window to the document surface and guide light reflected from the document surface to the photoelectric conversion element, and a cladding layer is provided around the outer periphery of the core. A contact image sensor characterized in that a space other than a waveguide between a glass substrate and a transparent protective layer is filled with a colored material. (2) The contact image sensor according to claim 1, wherein microsheet glass is used as the transparent protective layer. (3) The contact image sensor according to claim 1, wherein vapor-deposited glass is used as the transparent protective layer. (4) The contact image sensor according to claim 1, wherein a hard coat resin and a hard coat treated resin sheet are used as the transparent protective layer.