JPH0221189B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color document reading device used in facsimiles and the like. 2. Description of the Related Art There is a desire to develop an apparatus that can distinguish the colors of a document and record the document in two or more colors in a facsimile machine or the like.

This type of device usually captures the original through a lens.
It is a method that forms an image on a solid-state sensor such as a CCD and reads it.In order to perform color discrimination, a color separation prism is placed in the imaging optical path, and a beam of light with a specific color component is incident on each of the multiple solid-state sensors. In this way, color discrimination is performed using a logic circuit based on the color component output from the . Alternatively, the imaging optical system may be configured to include separate lenses and color filters for each color component.

These conventional devices have the disadvantage that accurate color discrimination cannot be performed because the same lens is used as a common imaging lens, or when multiple lenses of the same type are used, the imaging magnification differs depending on each color component. It was hot.

In addition, if lenses of different shapes and materials are made for each color component and the imaging magnification is made to be uniform, there is a drawback that a plurality of types of lenses must be manufactured, which increases costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive color document reading device that eliminates the above-mentioned defects, has accurate color discrimination, and is inexpensive.

The color document reading device according to the present invention includes a plurality of sensors provided corresponding to the number of desired wavelength bands to be read, and an imaging optical system that forms an image of the document on these sensors. and filter means provided on the sensor between the original and the sensor in order to guide a luminous flux in a desired wavelength band out of the luminous flux from the original; A plurality of sensors may be used in common, or an optical system having the same imaging characteristics may be used for each of the plurality of sensors, and the element arrangement pattern of the plurality of sensors may correspond to each wavelength of the imaging optical system formed on the sensor. The size of the light receiving section of the sensor and the size between the light receiving sections are determined in proportion to the imaging magnification of the color components of the band. The present invention will be explained in detail below.

FIG. 1 is a diagram showing a first embodiment of the present invention. 1 is a document, and 2 is a fluorescent lamp for illuminating the document.
13 and 14 are reading lines on the original 1, and 15 is a lens array, which is integrally molded from plastic such as PMMA (polymethyl methacrylate). Alternatively, it is also possible to make individual lenses from glass or plastic and arrange them. 16 is an aperture plate. Reference numeral 17 denotes a light shielding plate, which separates the imaging light flux of each lens and prevents light passing through an adjacent lens and stray light from entering the solid-state sensor. 18 is a cyan component transmission filter, and 19 is a red component transmission filter. 20 is a solid-state sensor substrate, and 21 and 22 are solid-state sensor arrays such as CCDs and photodiode arrays.

The read line 13 is imaged onto the solid state sensor array 22 by the lens array 15 . The individual lenses of the lens array 15 produce an inverted image of a portion of the reading line 13 on the solid-state sensor, but the output from each photoelectric converter of the solid-state sensor array 22 is electrically corrected in the order of one line of the original document. Can be rearranged.

Since a red component transmission filter 19 is inserted in the imaging optical path of the reading line 13, the output from the solid-state sensor array 22 is information on the red component of the original 1.

On the other hand, the reading line 14 is also connected to the lens array 1.
5 onto the solid state sensor array 21.
Since the cyan component transmission filter 18 is inserted in the imaging optical path of the reading line 14, the output from the solid-state sensor array 21 is information on the cyan component of the document 1. The solid-state sensor arrays 21 and 22 are arranged in accordance with the image plane of the cyan component and the image plane of the red component, respectively, and are separate planes.

The cyan component output from the solid state sensor array 21 is
The document 1 is delayed by the time required to be conveyed the distance between the reading line 14 and the reading line 13, and is input to the color discrimination logic circuit together with the red component output from the solid-state sensor array 22, where the two colors of red and black are discriminated. Ru.

As the original 1 is conveyed, the entire surface of the original 1 is read, and the image of the cyan component generated on the solid-state sensor 21 and the image of the red component generated on the solid-state sensor 22 are different from each other due to the chromatic aberration of the lens array 15. Since the imaging magnification differs when the wavelength range is different, the size of the image differs.

FIG. 2 is a schematic diagram of a portion of a solid state sensor array. 30 is a 1-bit light-receiving section of the solid-state sensor array 22, and 31 is a 1-bit light-receiving section of the solid-state sensor array 21. In FIG. 2, the lens array 15
A solid state sensor element corresponding to one of the lenses is shown. Length of solid-state sensor element array for red component
Length of solid sensor element array for L _R and cyan component
They are different from _LC , and each corresponds to the difference in the size of the original image depending on the wavelength range of light. In other words, the original image of the cyan component is larger than the original image of the red component.Proportionally, the length of the light-receiving part of the solid-state sensor for cyan component is P _C , and the length of the light-shielding part between the light-receiving parts
G _C and the length of the element row L _C are larger than the length P _R of the light-receiving part of the red component solid-state sensor, the length G _R of the light-shielding part between the light-receiving parts, and the length L _R of the element row. There is. This makes it possible to correct the influence of the chromatic aberration of magnification described above, and to perform correct color discrimination.

In this way, the element arrangement patterns of the red component sensor and the cyan component sensor are different in the size of the light receiving sections in the sensor column direction and the size between the light receiving sections.

The focal length of each lens of lens array 15 is
10mm, each with a reduction magnification of 4mm width of original 1
We created a device that forms an image on a solid-state sensor at 0.8x magnification.
As shown in FIG. 2, good results were obtained by changing the sensor element arrangement patterns of the solid state sensor 21 and the solid state sensor 22. The solid-state sensor used is a sensor made of amorphous silicon film, and the sensor pitch can be changed by changing the patterning by changing the mask that has the sensor element arrangement pattern for exposing the photoresist during the sensor manufacturing process. This was easily accomplished. The dimensions of the created sensor are P _R = 40 μm, G _R = 10 μm, L _R = 3.2 mm, P _C = 40.4 μm, G _C = 10.1 μm, L _C = 3.232 mm, and it can read documents with high resolution and correctly distinguish colors. We were able to. When the imaging lens system is a lens array as in this example, it is preferable that each lens be a convex single lens for the reason of ease of manufacturing. Although difficult, a method of changing the element arrangement pattern of the sensor for each color component is extremely effective.

FIG. 3 is a diagram showing a second embodiment of the present invention. 41, 42 are reading lines on the original 1, 43,
Reference numeral 44 indicates the same lens array, which is arranged with steps. 45 is a diaphragm plate, and 46 is a light shielding plate for separating the imaging light beams of each lens. 47 is a red component transmission filter, and 48 is a cyan component transmission filter. 49 is a solid-state sensor substrate, 50,5
1 is an array of solid-state sensors such as CCDs and photodiode arrays.

The read line 41 is imaged onto the solid state sensor array 50 by a lens array 43. The individual lenses of the lens array 43 produce an inverted image of a portion of the reading line 41 on the solid-state sensor, and the outputs from each photoelectric conversion section of the solid-state sensor array 50 are rearranged by electrical means into the correct order of one line of the original. It will be done.

Since a red component transmission filter 47 is inserted in the imaging optical path of the reading line 41, the output from the solid state sensor array 50 is information on the red component of the original 1.

On the other hand, the reading line 42 is also connected to the lens array 44.
The image is formed on the solid-state sensor array 51 by . Since a cyan component transmission filter 48 is inserted in the imaging optical path of the reading line 42, the output from the solid state sensor array 51 is information on the cyan component of the document 1. The cyan component output from the solid-state sensor array 51 is delayed by the time required for the document 1 to be conveyed the distance between the reading lines 42 and 41, and is input to the color discrimination logic circuit together with the red component output from the solid-state sensor array 50 to distinguish between red and black. Two colors are distinguished.

The lens arrays 43 and 44 are arranged at different distances from the original 1 so that the image planes of the original 1 for red and cyan components coincide with each other. Therefore, the solid sensor arrays 50 and 51 can be placed on the same plane, making it easy to manufacture and adjust the solid sensors. Although the image planes of the red and cyan components are the same, their respective imaging magnifications are generally different;
As described in the description of the embodiment, changing the sensor element arrangement pattern of the solid-state sensor for reading red and cyan components is effective in eliminating color shift.

Lens arrays 43, 44 and solid sensor array 5
0, 51, etc. can be arranged so that the same line of the original 1 is read. In this case, there is no need to delay one of the signals, and the signal processing circuit becomes simpler. This line can be read as an off-axis image of the lens arrays 43 and 44, and the lens array 4
3 and 44 can be tilted and read as an off-axis image.

In the embodiments described above, a two-color document reading device has been described, but the present invention can also be applied to a color document reading device that uses three or more colors. For example, in a full-color document reading device, color discrimination can be performed by installing solid-state sensors to read the red, green, and blue components of the document, but each sensor's element arrangement pattern is determined by the color component in charge. It is sufficient to change it according to the imaging magnification of the wavelength range.

Further, the document reading method is not limited to a method using a lens array. The present invention can be implemented in the same manner even with a configuration including one lens.

As described above, according to the present invention, it is sufficient to use a common lens or to use several lenses of the same type to read each color component in order to discriminate the color of a document, resulting in a low-cost color document reading device. Moreover, since the sensor element arrangement pattern of the solid-state sensor for each color component is changed according to the imaging magnification of each wavelength range of light, accurate color discrimination can be performed.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a first embodiment of the device according to the present invention, FIG. 2 is a schematic diagram showing a part of a solid-state sensor array applied to the device according to the present invention, and FIG. 3 is a perspective view showing a first embodiment of the device according to the present invention. FIG. 3 is a perspective view showing a second embodiment of the device. 1... Original, 15... Lens array, 18...
Cyan component transmission filter, 19...Red component transmission filter, 21, 22...Solid sensor row, 3
0: 1-bit light-receiving section of the solid-state sensor array for reading the red component, 31: 1-bit light-receiving section of the solid-state sensor for reading the cyan component.

Claims (1)

[Scope of Claims] 1. A plurality of sensors provided corresponding to the number of desired wavelength bands to be read, an imaging optical system for forming an image of a document on these sensors, and a plurality of sensors provided on the sensors. In the color document reading device, the imaging optical system includes a filter means provided between the document and the sensor to guide a light beam in a desired wavelength band out of the light beam from the document. The plurality of sensors are used in common or an optical system having the same imaging characteristics is used for each of the plurality of sensors, and the element arrangement pattern of the plurality of sensors is the same as the imaging optical system formed on the sensor. 1. A color original reading device, wherein the size of a light-receiving portion of the sensor and the size between the light-receiving portions are determined in proportion to the imaging magnification of color components in each wavelength band. 2 The element arrangement pattern of the plurality of sensors is:
For each sensor provided for each of the plurality of different wavelength bands, the size of the light receiving part in the sensor row direction,
A color document reading device according to claim 1, wherein the light receiving portions have different sizes.