JPH02237359A - Parallel optical element and color original reader - Google Patents

Abstract

PURPOSE:To comparatively easily adjust image forming by using a parallel optical element of a constitution where 3 optical elements having a thin and long incoming plane and outgoing plane respectively are integrated while being in contact with the longitudinal directions. CONSTITUTION:An original 1 is scanned and exposed and its reflected light is formed simultaneously to each array of a line image sensor 43 having 3 arrays of photoelectric conversion elements 43a-43c for different colors through an image forming means and a color separation means to obtain picture information. In this case, a parallel optical element 8 with the constitution which 3 optical elements 8a-8c having thin and long incoming plane and outgoing plane and integrated while being in contact with the longitudinal directions as a part of the image forming means respectively is used. Thus, the necessity of the line memory to obtain color decomposition image information is eliminated and the adjustment of image forming onto the 3-line image sensor is facilitated.

Description

[Detailed description of the invention] [Industrial field in Icheon] The present invention relates to a parallel optical element for color separation and a color original reading device used in a color copying machine, etc.
A color used in conjunction with an imaging lens to image linear reflected light from a scanning-exposed document onto each row of a line image sensor that has three parallel rows of photoelectric conversion element rows for light of different colors. This invention relates to a parallel optical element for separation and a color document reading device using the same.

[Conventional technology]

As a color document reading device, Journal of
lmaging Technology 14;68-
72 (1988), four methods shown in FIGS. 7 to 10 are known.

In the method shown in FIG. 7, a document 1 is scanned and exposed with a white light source 2, and linear reflected light from the document 1 is transmitted through an imaging lens 3 to a line image sensor 41 having substantially one row of photoelectric conversion elements. Red (R), green (G), and blue (
This method obtains color separation image information of a color image by switching and inserting color separation filters 5a, 5b, 5c such as B).
Since this method requires a driving means for switching the color, and it is not possible to simultaneously obtain R, G, and B information in one scan, there is a problem in reproduction of black color, etc.

In the method shown in FIG. 8, the original 1 is scanned and exposed using color separation light sources 2 a , 2 b , 2 c such as R, G, B, etc., and the reflected light from the original 1 is exposed as in the method shown in FIG. 7. This method uses an imaging lens 3 to form an image on a line image sensor 41, and this method requires color separation light sources 2a, 2b2c and switching drive means, and, like the method shown in FIG. 7, it is difficult to reproduce black, etc. There is a problem.

In the method shown in FIG. 9, linear reflected light from a document 1 is scanned and exposed by a white light source 2, and after passing through an imaging lens 3, two types of guichroic mirrors 5a and f3b are used to convert R, G, B, etc. This method separates the separated lights into separate colors and focuses each separated light on a line image sensor 41 similar to that shown in FIGS. Three line image sensors 41 are required, and complicated and highly accurate adjustment is required to form an image for each line image sensor 41.

In the method shown in Fig. 1O, three parallel rows of color separation filters such as R, G, and B are provided in front of the image forming lens 3 to scan and expose the linear reflected light of the original 1 with a white light source 2. 3-line image sensor 43 having a photoelectric conversion element array
This is a method in which images are formed in each row of 3 line image sensors 41 as in the method shown in FIG. 9, which requires a switching driving means as in the method shown in FIGS. 7 and 8. No adjustment required.

However, in the method shown in FIG. This is the reflected light from linear positions in each row whose positions are shifted according to the parallel spacing of the element rows. Therefore, in order to obtain color separation image information of reflected light from the same linear position that improves black reproduction, etc., it is necessary to deviate in time by the scanning time corresponding to the deviation of the linear position for each column mentioned above. The output information of the three photoelectric conversion element arrays must be combined.

Therefore, the output information of the three photoelectric conversion element arrays must be stored for the above-mentioned time period, which requires a large number of line memories and increases cost. When magnification is changed by changing the scanning speed, the number of line memories required increases in accordance with the maximum magnification, and thus the layer cost i· increases.

Therefore, as a color document reading device that solves the above-mentioned problems, a reading device as shown in Fig.
This is proposed by Publication No. 2. The reading device shown in FIG. 11 uses an imaging lens 3 to convert light on the optical axis of reflected light from positions on the same straight line scanned and exposed by a white light source 2 to a photoelectric sensor located at the center of a 3-line image sensor 43. Two mirrors 7a and 7b placed off the optical axis between the original l and the imaging lens 3 convert the off-axis portions of the reflected light into an image on the conversion element array. By focusing images on the photoelectric conversion element arrays on both sides of the central photoelectric conversion element array, the information simultaneously output by the three photoelectric conversion element arrays of the 3-line image sensor 43 is reflected from the same linear position. By providing color separation image information of light, there is no need to use a line memory. However, in this reading device, if the 3-line image sensor 43 is a 3-line COD in which three rows of photoelectric conversion elements are configured in one package, and the spacing between the three rows is narrow, the mirror 7a. It becomes difficult to arrange the mirrors 7b, making it difficult to put them into practical use.If the mirrors 7a, 7b are tilted, the image forming position of the reflected destination will be deflected at a rate twice the mirror's tilt. There is a problem in that it is very difficult to adjust the imaging position using the lens 7b.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned prior art, and uses a 3-line image sensor having three parallel rows of photoelectric conversion element rows for light of different colors to obtain color separation image information. This eliminates the need to use a color separation filter switching drive means, a color separation light source and its switching drive means, a dichroic mirror, and three line image sensors for each color, and allows for simultaneous scanning of originals scanned and exposed using a white light source. By separating the reflected light from a linear position without using a mirror and focusing it on each of the three photoelectric conversion element rows of the 3-line image sensor, the need for line memory to obtain color separation image information is eliminated. Our ultimate goal is to provide a color document reading device that can be relatively easily adjusted to form images on three rows of photoelectric conversion elements, and is used in the reading device together with an imaging lens to capture the same straight line of the document. A first object of the present invention is to provide an optical element that makes it possible to separate reflected light from different positions and form an image on each row of a three-line image sensor.

[Means to solve the problem]

The present invention has a configuration in which three optical elements each having a long and narrow entrance plane and an output plane are integrated with each other in contact with each other in the length direction, and the light from a linear image is transmitted in parallel to the three optical elements. A parallel optical element characterized in that it is used to make each light incident on each row of a line image sensor having three parallel rows of photoelectric conversion element rows for light of different colors, With this configuration, the first
achieve the purpose of

Further, the present invention scans and exposes a document, and passes the reflected light through an imaging means and a color separation means to each row of a line image sensor having three parallel rows of photoelectric conversion element rows for light of different colors. In a color document reading device that obtains image information by simultaneously forming images, three optical elements each having an elongated entrance plane and an elongated exit plane are integrated as part of the image forming means so that they are in contact with each other in the length direction. There is also a color document reading device characterized in that parallel optical elements having a configuration similar to the above are used, and this configuration achieves the above-mentioned final objective.

[Effect]

The parallel optical element of the present invention is used together with an imaging lens for a conventionally known line image sensor, and has three parallel rows of photoelectric conversion elements for light of different colors for obtaining color separation image information. In each row of a 3-line image sensor such as a line CCD, the same linear reflected light from a document scanned and exposed using a white light source can be separated and imaged, and the adjustment for this purpose is the same as that for a 3-line image sensor. Since three optical elements are integrated into one, by setting the distance between the optical axes of these optical elements corresponding to the distance between the rows of the 3-line image sensor, the parallel direction of the three optical elements can be adjusted. A comparison in which the parallel optical elements are moved in a direction parallel to the optical axis by making it perpendicular to the optical axis plane of the reflected light, and aligning the optical axis plane of the central optical element with the optical axis plane of the reflected light. It can be done in a very simple way.

Further, the color document reading device of the present invention uses a combination of the above-described parallel optical element and 3-line image sensor, and also performs color separation by providing either the parallel optical element or the 3-line image sensor with a color separation filter. This eliminates the need for color separation filters, switching drive means for color separation light sources, dichroic mirrors, and three color-specific line image sensors, and eliminates the need for line memory to obtain color separation image information. This makes it possible to use a 3-line image sensor configured in one package, such as a 3-line CCD, and to relatively easily adjust the image formation on the 3-line image sensor.

〔Example〕

Hereinafter, the present invention will be described by way of examples with reference to FIGS. 1 to 6.

Fig. 1 is a principle diagram of the parallel optical element of the present invention, Fig. 2 is a partial perspective view of the parallel optical element of Fig. 1, and Fig. 3 is a 3-line COD.
FIGS. 4 and 5 are side views and partial perspective views showing other examples of the parallel optical element of the invention, and FIG. 6 is a schematic configuration diagram showing an example of the color original reading apparatus of the invention.

In Figs. 1 to 6, the same reference numerals as in Figs. 7 to 11 indicate the same functional members, and numeral 8 denotes three optical elements 8a, 8b, 8c each having an elongated entrance plane and an elongated exit plane. This is a parallel optical element consisting of an integrated configuration. If this parallel optical element 8 is not used, the 10th
Similarly to the figure, in FIG.
The position of the first surface of the document where the image is formed at c is a linear position 1b perpendicular to the paper plane at the starting point of the overall central optical path, and a linear position perpendicular to the paper plane at the starting point of the optical path indicated by the two-dot chain line above and below. There are three positions such as positions 1b and lc, but by using these positions, the photoelectric elements 8a and 8c respectively refract the optical paths shown by the two-dot chain lines as shown by the solid lines, and the starting points of those optical paths can be changed. This is to match the starting point of the central optical path. Coincidence can be easily achieved by moving the parallel optical element 8 back and forth in the optical axis direction.

That is, by using the parallel optical element 8, the same linear reflected light from the original 1 is transmitted through the imaging lens 3 to the three photoelectric conversion element arrays 43a, 43 of the three-line image sensor 43.
It is possible to focus the images on b and 43c. I want to, 3
What type of color separation filter should be used in the line image sensor 43 in front of each photoelectric conversion element array 43a, 43b, 43c, or should a color separation 7 filter be used in the parallel optical element 8 and each optical element 8a, 81], 8c. By using one on one or both of the incident plane or the output plane of the image sensor, the color separation image information can be read by the three-line image sensor 43 without requiring a line memory.

In addition, the parallel optical element 8 of FIG. 1 whose perspective view is shown in FIG.
Although it is preferable that the central optical element 8b is an optical element that does not refract an optical path in which the incident plane and the yaw incidence plane are parallel, the parallel optical element 8 of the present invention is not limited to this. The element 81) may be one that refracts the optical path. Further, as a preferable parallel optical element 8 in which the central optical element 8b does not refract the optical path, those shown in FIGS. 4 and 5 are also more preferable from the viewpoint of ease of manufacture. Further, if the color separation filter is provided for at least two of the three rows of the three-line image sensor 43 and two of the optical elements 8a, 8b, and 8C of the parallel optical element 8, the color separation image information can be transmitted. Obtainable.

The 3-line image sensor 43 shown in FIG. 3 has three photoelectric conversion element rows 43a, 43b, and 43c having color separation filters on the front and outputs color separation image information, and the pitch between the rows is This is a 3-line CCD constructed in one package with approximately Oi7nu++, and is actually available. The parallel optical element 8 as shown in FIGS. 1.2 and 3.4 is a photoelectric conversion element row 43a of a 3-line image sensor 43 in which the pitch of each optical element 8a, 8b, 3c is as described above. , 43b. It is possible to easily make one corresponding to the inter-row pitch of 43c.

In the color document reading device shown in FIG. 6, a document 1 is placed on a document table glass 9 and is illuminated by a white light source 2 of a halogen lamp attached to a scanning member 10 that slides in the horizontal direction. The scanning member 10 is provided with the above-mentioned parallel optical element 8 and mirror I1 at an angle of 45 degrees. By configuring the illumination system and the parallel optical element 8 integrally in this way, the relationship between the illumination distribution state on the document 1 by the illumination system and the imaging position can be easily maintained, and the illumination distribution can be adjusted when replacing the light source, etc. becomes easier. Movable mirror unit
Mirrors l3 and 14 are mounted on 12 at an angle of 90° and also slide horizontally at 1/2 the speed of the scanning member 10. After the reflected light from the original 1 passes through the parallel optical element 8, it passes through the mirrors 11, 13, 14.
The image information of line A on the document l is sent to the imaging lens 3 by the combination of Images are formed on 43a, 43b, and 43c.

Therefore, color separation image information with excellent black reproducibility can be read by the three-line image sensor 43 without requiring a line memory.

〔Effect of the invention〕

The parallel optical element of the present invention is used together with an imaging lens for a conventionally known line image sensor, so that each row of a 3-line image sensor such as a 3-line CCD is scanned and exposed using a white light source, and the same straight line is scanned from the original. This has the effect that the reflected light can be separated and imaged, and adjustment for this purpose can be easily performed.

Furthermore, the color document reading device of the present invention eliminates the need for a color separation filter, a switching drive means for a color separation light source, a dichroic mirror, and three line image sensors for each color, and is capable of obtaining color separation image information. This eliminates the need for a line memory, makes it possible to use a 3-line image sensor configured in one package, such as a 3-line CCD, and makes it easy to adjust the image formation on the 3-line image sensor. It has the desired effect.

[Brief explanation of drawings]

Fig. 1 is a principle diagram of the parallel optical element of the present invention, Fig. 2 is a partial perspective view of the parallel optical element of Fig. 1, and Fig. 3 is a 3-line CCD.
FIGS. 4 and 5 are side views and partial perspective views showing other examples of the parallel optical element of the invention, FIG. 6 is a schematic configuration diagram showing an example of the color document reading device of the invention, and FIG. 1 to 11 are schematic configuration diagrams each showing an example of a conventional color document reading device. 1... Original 2... White light source 2a, 2
b, 2c... Color separation light source 3... Imaging lens 4l... Line image sensor 43... 3 line image sensors 43a, 43b, 43c = optical conversion element rows 5a, 5b
, 5c... Color separation filters 6a, 6b... Dichroic mirrors 7a, 7b... Mirror 8... Parallel optical element 8
a, 8b, 8c - optical element

Claims (5)

[Claims] (1) It consists of a structure in which three optical elements, each having a long and narrow entrance plane and an output plane, are integrated so that they are in contact with each other in the length direction, and light from a linear image is transmitted in parallel to the three optical elements. A parallel optical element characterized in that it is used to make each light incident on each row of a line image sensor having three parallel rows of photoelectric conversion element rows for light of different colors. (2) The parallel optical element according to claim 1, wherein the entrance plane and exit plane of one central optical element among the three optical elements are parallel. (3) The original is scanned and exposed, and the reflected light is passed through an imaging means and a color separation means to form an image simultaneously on each row of a line image sensor having three parallel rows of photoelectric conversion element rows for light of different colors. In a color document reading device that obtains image information by scanning, a parallel optical element is constructed in which three optical elements, each having an elongated entrance plane and an exit plane, are integrated so as to be in contact with each other in the length direction as part of the imaging means. A color document reading device characterized by using an optical element. (4) The color document reading device according to claim 3, wherein the color separation means comprises a filter provided in front of a photoelectric conversion element array of a line image sensor. (5) The color document reading device according to claim 3, wherein the decomposition means comprises a filter provided on at least one surface of an incident plane or an exit plane of the optical element of the parallel optical element.