JPH1032676A - Color separation filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the color separation filter made small in size in a color original reader used for an input device for a computer or the like. SOLUTION: A reflected light of an original emitted by a light source is reduced by a lens 17 and passes through a color separation filter 18, which is driven by a motor 19 to input the light to a line image sensor 16. In the color separation filter as above, the color separation filter 18 is placed just after the lens 17 to decrease the width of an optical path 20 passing through color filters 18R, 18G, 18B so as to make the color separation filter small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color separation filter device used in a color document reading device.

[0002]

2. Description of the Related Art Generally, when an image drawn on a document is input to various image reading devices, the image drawn on the document is decomposed into pixels having a structure of a predetermined size, and the density (or luminance) of the image is determined. 2. Description of the Related Art An image reading apparatus that photoelectrically converts an electric signal corresponding to the above-mentioned method into an electric signal and outputs the signal in a state where images are arranged in time series is used. In addition, a color document reading apparatus that reads an image drawn on a document including its color information has been put to practical use.

In such a color document reading apparatus,
Similar to a monochrome original reading apparatus, the original surface is illuminated by a light source, the reflected light is focused on a line image sensor via a lens, and an image signal is obtained from the line image sensor. Various mechanisms and circuits necessary for obtaining an image signal are added.

This color original reading apparatus has a fan-shaped 3
Filters of the type (R, G, B) are arranged on the circumference to form a single disk-shaped color separation filter, and the color separation filter is used for each line in the reading direction of a color original by using a DC motor or the like. Is rotated to switch between three types of color filters, and the reflected light from the original surface passes through each color filter to be decomposed into three primary color light signals, and the light signals are applied to the line image sensor for a certain period of time. As a result, a color original is read by obtaining image signals of three primary colors for each line.

Hereinafter, a conventional color separation filter device will be described. FIG. 5 is a principle diagram of a color document reading apparatus using a conventional color separation filter device, and FIG. 6 is a perspective view of the same color separation filter device. 5 and 6, reference numeral 1 denotes a document to be read, 2 denotes a light source for irradiating the document 1,
Reference numerals 4 and 5 denote reflecting mirrors for adjusting the direction of the reflected light of the original 1. Reference numeral 6 denotes a line image sensor for reading image information of the original 1.
Denotes a lens for reducing image information of the original 1 to a reading size of the line image sensor 6, and 8 denotes a color separation filter.
It is composed of three fan-shaped color filters 8R (red filter), 8G (green filter), and 8B (blue filter) having different spectral characteristics, and is disposed immediately before the line image sensor 6. Reference numeral 9 denotes a motor for rotating the color separation filter 8.

The operation of the conventional color separation filter device configured as described above will be described below with reference to the principle diagram of an image reading apparatus using the conventional color separation filter device shown in FIG. First, the reflected light of the light emitted from the light source 2 to the original 1 is guided to the lens 7 through the reflecting mirrors 3, 4, and 5, and the optical path 10 is formed so as to be received by the line image sensor 6 through the color separation filter 8. Is done. When the color separation filter 8 is rotated by the motor 9 when the optical path 10 passes through the color separation filter 8, the same pixel on the line image sensor 6 can receive the reflected light of the same portion on the document 1. The same part can be color-separated for each color without deteriorating the resolution.

[0007]

However, in the above-described conventional method and configuration, since the color separation filter 8 is disposed immediately before the line image sensor 6, the size of the optical path 10 passing through the color separation filter 8 is limited to a line. The reading width of the image sensor 6 is almost the same, and the shape of each color filter and the shape of the color separation filter are increased.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a color separation filter device capable of reducing the size of a color separation filter and consequently reducing the size of a color document reading device. And

[0009]

According to a first aspect of the present invention, there is provided a color separation filter in which a plurality of color filters having different spectral characteristics are arranged in a fan shape, and one of the read originals.
A driving means for rotating the color separation filter in the circumferential direction for each line to switch the color filters, and a driving means arranged on the back of the color separation filter and allowing the color filters to act one by one by the driving means, A color separation filter device comprising: a line image sensor that obtains each color image signal for a period; and a lens disposed in front of the color separation filter and configured to reduce a read original to a reading size of the line image sensor. A filter was placed immediately after the lens between the lens and the line image sensor.

[0010] According to a second aspect of the present invention, the driving means is disposed between the lens and the line image sensor.

According to a third aspect of the present invention, there is provided a color separation filter in which a plurality of color filters having different spectral characteristics are arranged in a fan shape, and the color separation filter is rotationally moved in a circumferential direction for each line of a read document. A driving means for switching the color filters, a line image sensor arranged on the back of the color separation filter, and sequentially operating each color filter one by one by the driving means to obtain each color image signal during the period; A color separation filter device comprising a lens disposed on a front surface of a filter and configured to reduce a read document to a reading size of the line image sensor, wherein an effective light beam passing through the color separation filter is disposed in a radial direction of the color separation filter. The color separation filter was arranged so as to pass in parallel to the color separation filter.

[0012]

According to the first aspect of the present invention, the shape of the color separation filter is reduced in size, whereby the effective light beam passing through the color separation filter can be reduced.

According to the second aspect of the present invention, the distance between the center of the driving means and the center of the optical path can be reduced. According to the third aspect of the present invention, the shape of the color separation filter can be reduced in size, whereby the effective light flux passing through the color separation filter can be reduced.

Hereinafter, embodiments of the present invention will be described. FIG. 1 is a principle diagram of a color document reading apparatus using a color separation filter device according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view of the same color separation filter device.

In FIGS. 1 and 2, reference numeral 11 denotes a document to be read, 12 denotes a light source for irradiating the document 11, 13, 14,.
15 is a reflecting mirror for adjusting the direction of the reflected light of the original 11, 16
Is a line image sensor for reading the image information of the document 11, 17 is a lens for reducing the image information of the document 11 to the reading size of the line image sensor 16, 18 is a color separation filter, and three fan-shaped color filters having different spectral characteristics. 18R (red filter), 18G (green filter), 1
8B (blue filter), which is disposed immediately after the lens 17. Reference numeral 19 denotes a motor for rotating the color separation filter 18.

The operation of the above-configured color separation filter device will be described below with reference to FIG. First, the reflected light of the light emitted from the light source 12 to the document 11 is
An optical path 20 is formed so as to be guided to the lens 17 via the reflecting mirrors 13, 14, 15, and received by the line image sensor 16 via the color separation filter 18. By rotating the color separation filter 18 with the motor 19 when the optical path 20 passes through the color separation filter 18, the same pixel on the line image sensor 16 can receive the reflected light of the same portion on the document 11. The same part can be color-separated for each color without deteriorating the resolution.

According to this configuration, since the color separation filter 18 is located immediately after the lens 17, the line image sensor 1
The width of the optical path 20 passing through the color separation filter 18 is smaller than that in the case immediately before 6, and the size of the color separation filter 18 can be reduced.

Next, a second embodiment of the present invention will be described in detail with reference to the drawings. FIG. 3 is a perspective view of a color separation filter device according to Embodiment 2 of the present invention. FIG. 4 is an external view of a color separation filter of the same color separation filter device. FIG. 3 differs from FIG. 2 in that the positional relationship between the color separation filter and the line image sensor is different. That is, in FIG. 2, the optical path 20 passes through the color separation filter 18 in a form orthogonal to the radial direction of the color separation filter 18. However, in FIG. 3, the optical path 20 passes parallel to the radial direction of the color separation filter 18.

According to this configuration, the time required for the optical path 20 to pass through the color separation filter 18 can be extended as shown in FIG. 4A, so that the optical path 20 can be separated as shown in FIG. The size of the color separation filter 18 can be reduced as compared with the case where the light passes through the color separation filter 18 in a form orthogonal to the radial direction of the filter 18. As described above, in the second embodiment, the optical path 20 corresponds to the color separation filter 18.
The color separation filter 18 can be reduced in size by arranging it so as to pass in parallel to the radial direction.

[0020]

As described above, according to the present invention, a color separation filter is arranged immediately after a lens or an optical path is arranged so as to pass parallel to the radial direction of the color separation filter. Can be reduced in size.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a color document reading apparatus using a color separation filter device according to a first embodiment of the present invention;

FIG. 2 is a perspective view of a color separation filter device according to Embodiment 1 of the present invention.

FIG. 3 is a perspective view of a color separation filter device according to a second embodiment of the present invention.

FIG. 4 is an external view of a color separation filter of a color separation filter device according to a second embodiment of the present invention.

FIG. 5 is a principle diagram of a color document reading apparatus using a conventional color separation filter device.

FIG. 6 is a perspective view of a conventional color separation filter device.

[Explanation of symbols]

 11 Document 12 Light source 13, 14, 15 Reflector 16 Line image sensor 17 Lens 18 Color separation filter 18R Red filter 18G Green filter 18B Blue filter 19 Motor 20 Optical path

Claims (3)

[Claims] 1. A color separation filter in which a plurality of color filters having different spectral characteristics are arranged in a fan shape, and a drive for switching the color filters by rotating the color separation filter in a circumferential direction for each line of a read document. Means, a line image sensor arranged on the back of the color separation filter, and sequentially operating each color filter one by one by the driving means, and obtaining a color image signal during the period, and a line image sensor arranged on the front of the color separation filter, What is claimed is: 1. A color separation filter device comprising a lens for reducing a read document to a reading size of the line image sensor, wherein the color separation filter is disposed immediately after the lens between the lens and the line image sensor. Characteristic color separation filter device. 2. The color separation filter device according to claim 1, wherein said driving means is disposed between said lens and said line image sensor to reduce the size of said color separation filter. 3. A color separation filter in which a plurality of color filters having different spectral characteristics are arranged in a fan shape, and a drive for switching the color filters by rotating the color separation filter in a circumferential direction for each line of a read document. Means, a line image sensor arranged on the back of the color separation filter, and sequentially operating each color filter one by one by the driving means, and obtaining a color image signal during the period, and a line image sensor arranged on the front of the color separation filter, What is claimed is: 1. A color separation filter device comprising a lens for reducing a read document to a read size of said line image sensor, wherein an effective light beam passing through said color separation filter passes parallel to a radial direction of said color separation filter. A color separation filter device comprising the color separation filter.