JPH01181377A - Picture reader - Google Patents

Abstract

PURPOSE:To improve the lighting efficiency by providing a light distribution means distributing the illumination light from a lighting light source to each read element optically in a conjugation position. CONSTITUTION:A lamp unit 9 is provided with a reflection shade 14 as a light distribution means reflecting and distributing the light from a light source lamp 8 toward nearly conjugation positions optically with respect to CCD 1-3, that is, 1st-3rd read points R1-R3 provided with the 1st-3rd reflection faces 14a-14c. Since the illumination light lighting the face of an original 5 is distributed to nearly conjugation locations optically with respect to the plural CCD 1-3 by the distribution means 14, the luminous quantity of picture light incident to the CCD 1-3 is increased. Thus, the picture reader lighted efficiently is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image reading device used in, for example, a color copying machine, a facsimile machine, or an input device for a computer, and particularly relates to the structure of an illumination system for illuminating a document image.

(Prior Art) Conventionally, as this type of image reading device, there is one shown in FIG. 7, for example. That is, 100 is placed behind the imaging lens 101, and converts the image light of the original 102 into R(
red), G (green).

It is a prism that separates the wavelength into three colors of B (blue), and three reading elements 103, 104, 105 such as COD are arranged at positions corresponding to the separated image lights of each color to read the image of a color original. However, in the case of color separation using such a prism lOO, the prism 10
0 is expensive. In addition, three reading elements 103, 1
04° 105 had to be aligned separately, and furthermore, the alignment had to be done between the prism 100, the lens 101, and each of the reading elements 103, 104, and 105, making the adjustment work very difficult.

In order to solve these problems, a reading means 109 is used in which three lines of reading elements 106 and 107°1'08 are placed close to each other and monolithically assembled as one body, as shown in FIG. There is.

That is, each reading element 106 , 107 , 108 reads different color information, and the original image light illuminated by the illumination light source 110 is transmitted to the reading element 106 , 108 through the imaging lens 101 .
Images are formed on 107 and 108 to read the color information of the original image. Therefore, the prism 100 for separating image light as in the first example shown in FIG. 7 is not required, and the positioning of the reading means 109 becomes easy.

(Problem to be Solved by the Invention) However, in the case of such a prior art, the reading elements 106, 107°lO8, which are seven-dimensionally configured, are located close to each other but are located apart from each other, and the Reading position R by each reading element 106°107.108
,',R2'.

R3' are positions separated from each other in the reading scanning direction of the original 102. However, the illumination light L' from the illumination light source 110 is
It is configured to focus light on one point P using a reflective shade, etc., and the reading element 1 is arranged with this light focusing position P in the center.
07, the document surface at the reading positions R1' and R:l' on both sides will become dark. Therefore, each reading element 106, 107, 10
There was a problem that variations occurred in the information read by No. 8, resulting in inaccurate reading.

The present invention has been made in order to solve the problems of the prior art described above, and its purpose is to solve the problems of the prior art described above. An object of the present invention is to provide an image reading device that can efficiently illuminate an upper reading position.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a reading means in which a plurality of line-shaped reading elements for reading different color information are arranged close to each other, and the reading means is provided with a reading means in which a plurality of linear reading elements for reading different color information are arranged close to each other, and the reading means is illuminated by an illumination light source. In an image reading device, the image light of the original image is imaged on a reading means via an imaging optical system, and each reading element reads different color information in the original image.

The present invention is characterized in that a light distribution means is provided for distributing light to optically substantially conjugate positions with respect to the plurality of reading elements via the imaging optical system.

(Function) Since the illumination light that illuminates the document surface is distributed by the light distribution means to a position that is optically approximately conjugate to the plurality of reading elements, the amount of image light incident on each reading element can be controlled. can be increased.

(Example) The present invention will be explained below based on the illustrated example. 1st
In FIG. 1 and FIG. 2, 1, 2, and 3 are red (R) and green (G), respectively, in FIG.

One-dimensional C as a reading element that reads blue (B) color information
At OD, a document 5 placed on a document table 4 made of a transparent glass plate or the like and illuminated by a light source lamp 8 is transferred to an imaging optical system 6.
The image is scanned through the CCDI and focused on each CCDI, 2.3. Each C0DI, 2.3 is monolithically assembled on one substrate Ao to constitute the reading means A. The light-receiving surfaces of each CCDI, 2.3, are arranged so as to coincide with the imaging surface S of the optical system 6, and are arranged vertically symmetrically with respect to the optical axis 0 of the imaging lens 7, with a slight gap between them. are located close together.

The imaging optical system 6 includes a lamp unit 9 in which a light source lamp 8 as an illumination light source that approximately illuminates the document surface is assembled, a movable mirror unit 10 that moves at a slow speed with respect to the lamp unit 9, and It is composed of an image lens 7. The lamp unit 9 includes a first mirror 11 that reflects the original image illuminated by the light source lamp 8 toward the movable mirror unit 10, and a second mirror 11 provided on the movable mirror unit 10. Each CCDI of the reading means A turns the light beam of the image light toward the imaging lens 7 by the third mirror 12-13.

The image is formed on 2.3.

The reading information of the manuscript read in C0DI, 2.3 above is as follows:
The first CGDI, 2.3, which is located at a substantially conjugate position optically via the imaging lens 7, is located on the document in the scanning direction of the document by the distance that each C0DI, 2.3 is vertically apart. ．． Second. The image is the third reading point 1'R1+R2+R3.

On the other hand, the lamp unit 9 receives the illumination light from the light source lamp 8 via the imaging lens 7,
, 2.3, that is, the first to third reading points R] * R2l The first . Second. third reflective surface 14a,
14b.

A reflective shade 14 as a light distribution means is provided.

The first reflective surface 14a is arranged on the back side of the light source lamp 8 with respect to the scanning direction, and is a concave surface forming a part of a first ellipse Bl having two focal points approximately at the light source lamp 8 and the first reading point (R+). ing. Further, the second reflective surface 14b is a light source lamp 8.
It has a concave surface forming a part of a second ellipse B2, which has two focal points approximately at the second reading point R2 and the light source lamp 8. On the other hand, the third reflective surface 14c is disposed facing the light source lamp 8 in the scanning direction, and
It is a concave surface that forms a part of a third ellipse B3 having substantially two focal points at R3 and the third reading point).

It is desirable that the shape of each of these reflecting surfaces 14a, 14b, and 14c is not completely elliptical with two focal points.

That is, if the illumination width on the document surface becomes too narrow when the elliptical shape has completely two focal points, there is a tendency that the precision requirements for raising the document 5 or assembling the document 5 become too strict. If the elliptical shape does not have two focal points, the illumination width can be expanded, which is advantageous.

Also, 1st. second and third reflective surfaces 14a;

Instead of curved surfaces 14b and 14c, polygonal reflective surfaces 14a' and 14b' approximate an ellipse as shown in FIG.
, 14c. If the reflective shade 14' is formed into a polygonal shape like this, it becomes easy to manufacture the reflective shade 14'.

In the image reading apparatus configured as described above, the original 5 on the transparent original table 4 is illuminated by illumination light from the light source lamp 8 disposed below the original table 4.

The illumination light directed toward the back side from the light source lamp 8 is reflected by the first reflective surface 14a of the reflective shade 14, and is mainly distributed around the first reading point (R+) located near the approximate focal point of the first ellipse Bl. be done.

On the other hand, the light distributed below the light source lamp 8 is reflected by the reflective shade 1.
The light is reflected upward by the second reflecting surface 14b of No. 4 and distributed mainly around the second reading point R2, thereby amplifying the illuminance around the second reading point R2. Further, the light directed forward from the light source lamp 8 is distributed near the third reading point R3 of the original 5 by the third reflective surface 14c, increasing the illuminance near the third reading point R3.

In this way, the first reflection shade 14. Second. Third reflective surface 14
a, 14b, and 14c emit light from the illumination lamp 8 in a direction other than the document 5. Second. Light is distributed to the third reading point R1r R2*R3, and each reading point R1, R2.

The amount of light on the document surface of R3 increases. Therefore, the first. Second. The first . Second. The image light incident on the third CCDI, 2.3, can be increased and one image can be read accurately.

Here, since the sensitivity of the COD is usually low at the front B, it is preferable to arrange the first reading point R1 closest to the light source lamp 8 in the figure and the blue reading COD at a conjugate position.

FIG. 6 shows an illumination system of an image reading device according to a second embodiment of the present invention, in which red (R), red (R),
In the second embodiment, an image is read using a monolithic 3-line CCD array 1°2.3 reading means A that reads color information of the three colors green (G) and blue (B). Each C
CDI, 2°3, and three first . Second. A cylindrical lens group 15 is arranged as a light distribution means for distributing light to the third reading point R+*R2#R3. The cylindrical lens group 15 is disposed between the light source lamp 8 and the document 5, and is arranged between the first and second cylindrical lenses. Second. Lens parts 15a, 15b, 15c that focus the illumination light from the light source lamp 8 onto the third reading point R1*R2*R3
It is constructed by assembling them together. If such a cylindrical lens group 15 is manufactured monolithically by plastic molding or the like, an inexpensive and lightweight illumination system can be obtained. In this case as well, since the first reading point (R1) closest to the light source lamp 8 has the highest illumination efficiency, the CO
It is desirable to arrange D at a conjugate position, and each reading point RI+R2, R3 and cylindrical lens group 1
Regarding the arrangement of the parts 5 and 5, it is preferable not to have a perfect optical conjugate relationship, but to deviate the parts a little from each other in order to increase the tolerance for mounting accuracy and the like.

In each of the above embodiments, a reading means is described in which a monolithic 3-line CCD array is used to read the three colors of blue, red, and green. Needless to say, the present invention can be similarly applied to a device using a reading means having the above CCD array. Also, reading color information by each CGDI, 2.3 is as follows:
Although not shown, for example, CCD1. Glue the filters of each color to the cover glass covering...
D1. This is carried out by placing a filter in the optical path of the image light incident on the image light of a predetermined color. Of course, it is also possible to use other photoelectric conversion elements that can themselves recognize colors of specific wavelengths without providing a filter.

(Effects of the Invention) The present invention consists of the above-described configuration and operation, and includes a prism for dividing one image light by using a monolithic reading means in which a plurality of reading elements that read different color information are arranged close to each other. etc. are not necessary, and one position adjustment becomes easy. Also, lighting 11Ai! , is provided to distribute the illumination light from the illumination light source to a position optically conjugate to each reading element. The reduction in illuminance due to the diffusion of light is eliminated, and lighting efficiency can be increased.
Various effects such as the ability to read color images more accurately can be obtained.

[Brief explanation of the drawing]

1 and 2 show an image reading device according to a first embodiment of the present invention, in which FIG. 1 is a schematic configuration diagram of the vicinity of the light source lamp, FIG. 2 is a schematic front view showing the overall configuration of the device, 3 is a schematic plan view of the reading means of the device shown in FIG. 1, and FIG.
FIG. 5 is a schematic configuration diagram showing another aspect of the reflective shade shown in FIG. 1, and FIG. 6 is a longitudinal sectional view of the reading means in the figure. Schematic configuration diagrams FIGS. 7 and 8 are front views showing the schematic configuration of a conventional image reading device. Explanation of symbols 1.2.3... 1st. Second. 3rd COD (reading element) 5... Original 6... Imaging optical system 8...
- Illumination lamp (illumination light source) 14... Reflective shade (light distribution means) 14a, 14b, 14cm -- 1st. Second. Third reflective surface 15...Cylindrical lens group (light distribution means) 15a
, 15b, 15c・-L/7's part Fig. 2・5 Yellow part Fig. 5

Claims (4)

[Claims] (1) A reading means is provided with a plurality of line-shaped reading elements arranged close to each other to read different color information, and the image light of the original image illuminated by the illumination light source is imaged on the reading means via an imaging optical system. , an image reading device that reads different color information in a document image by each reading element, wherein illumination light from the illumination light source is directed to a position optically approximately conjugate to the plurality of reading elements via the imaging optical system. 1. An image reading device comprising: a light distribution means for distributing light. (2) The image reading device according to claim 1, wherein the light distribution means is a reflecting member formed of an elliptical group having substantially two focal points at a conjugate position with respect to each reading element and the illumination light source. . (3) The image reading device according to claim 2, wherein the elliptical shape of the reflecting member is an approximate polygonal shape. (4) The image reading device according to claim 1, wherein the light distribution means is a cylinder lens group.