JPS60253366A - Color original reader - Google Patents

Abstract

PURPOSE:To attain the optional control of the color balance of a color original by revolving the 1st and 2nd dichroic mirrors and a compensator in the same direction and at the same angle within each face and at the same time revolving the 1st and 2nd solid state image sensors in the same direction and at an angle double as large as the rotary displacement angle. CONSTITUTION:The 1st dichroic mirror 2 set so as to secure an incident angle theta for the light on an optical axis OA within a radial face is revolved at an angle alpha toward the 1st solid state image sensor 10 within the radial face. Under such conditions, the sensor 10 is turned by 2alpha from its reference position of theta(=45 deg.). As a result, the reflected light given from the mirror 2 is made incident rectangularly on the sensor 10 to secure the correct image formation. In the same way, the 2nd dichroic mirror 14 is turned at an angle alpha toward the 2nd solid state image sensor 11 within a tangential face. Then the reflected light given from the mirror 14 is made incident rectangularly on the sensor 11 to secure the correct image formation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a color original reading device for use in fac/millimeter or digital/tall color copying machines.

(Prior art) In a color document reading device, a color document is separated into the three primary colors of blue, red, and green using a color separation system. /I can't read it.

As a color separation optical system, a direct separation method using prisms and rhythms, which is used in 3P color cameras for broadcasting, is known, but this method has difficulty in positioning the prisms and fixing them, and also has problems with processing accuracy. It is difficult and expensive, and it is still very difficult to adjust the position of the light receiving element. In addition, in a color separation optical system using a dichroic mirror, it is necessary to use a relay lens to remove astigmatism caused by the dichroic mirror, which makes the structure complex and increases the number of optical elements such as lenses and mirrors. Therefore, there is a large loss of light quantity, and care must be taken to avoid the occurrence of flare or ghosts.

JP-A-54-48258 discloses a color separation optical system using a dichroic mirror that eliminates astigmatism without using a relay lens.

As shown in FIGS. 9 and 10, the first dichroic mirror 2 formed on one side of the first parallel plane substrate 1 and the thickness A of the first parallel plane substrate 1 a second dichroic mirror 5 formed between second and third parallel plane substrates 3 and 4 respectively having
A second dichroic mirror 5, which is irradiated with the incident light that has passed through the dichroic mirror 2, is arranged in a position rotated by 90° with respect to the first dichroic mirror 2 around the optical axis OA of the incident light. be. The first and second dichroic mirrors 2 and 5 each have an optical axis O
It is tilted at the same angle of 45° with respect to A. For convenience of explanation, in FIG. 7, a plane parallel to the plane of paper is defined as a radial plane, and in FIG. 8, a plane parallel to the plane of paper, that is, perpendicular to the radial plane, is defined as a radial plane.

When a line scanning type document reading device is configured using such a color separation optical system, reflected light from the color document 8 illuminated by the light source 6 in a slit shape and sent over the document table glass 7 in the direction of the arrow. After passing through the condensing lens 9, the red component light is reflected by the first Gikroitz mirror 2 and enters the first solid-state image sensor 10, where the red component image is read by self-scanning. It will be done. The light transmitted through the first dichroic mirror 2 then enters the second dichroic mirror 5, and the green component light transmitted through the blue color 5 enters the third solid-state image sensor 12. The green component image is read and carried.

The light transmitted through the first Gikkreuzk mirror 2 is
Although astigmatism occurs due to the light passing through the parallel plane substrate 1, the parallel plane substrates 3 and 4 on both sides of the second dichroic mirror 5 are 3 and 4, the astigmatism generated in the first parallel plane substrate 1 is reversely corrected.

However, a problem with the document reading device having such a configuration is the ghost image appearing on the second solid-state image/sensor 11. A ghost image also appears on the first solid-state image sensor 10 due to reflection from the back surface of the first parallel plane substrate 1, but as shown in FIG. However, as shown in FIG. 12, the ghost image appearing on the second solid-state image/sensor 11 is a coast image 82' caused by surface reflection of the second parallel plane substrate 3 on the same line as the normal image S2. is shifted slightly to the left, and the ghost image s2 due to reflection from the back surface of the third parallel plane substrate 4 appears shifted slightly to the right, making it impossible to read only the correct signal.

Therefore, the applicant of the present application previously proposed a document reading device in Japanese Patent Application No. 177486/1986 to prevent signal reading errors caused by such ghost images on the second solid-state image sensor. As shown in FIG. 13 and FIG.
and the configuration up to the first solid-state image/sensor 10 is the ninth
Although the structure is the same as that shown in FIG. 1 and FIG. The optical axis OA is formed on the surface of the lens and placed in a position where the optical axis OA is rotated 900 degrees. Further, between the second dichroic mirror 14 and the second solid image/sensor 11, there is provided a compensator 15 which is a parallel plane plate made of the same material and of the same thickness as the first and second parallel plane substrates 1 and 13. is arranged parallel to the second dichroic mirror 14. Each of the parallel plane substrates 1 and 13 and the compensator 15 are arranged at an angle with respect to the optical axis OA so that the incident angles on the optical axis OA are the same θ in the radial plane and in the tandiene/kill plane, respectively. The first dichroic mirror 2 is a red reflective mirror, but it can also be a blue reflective mirror. In this case, the second dichroic mirror 14 is a red reflective mirror.

The light beam including astigmatism that has passed through the first parallel plane substrate 1 is
A part of it is reflected by the second dichroic mirror 14,
By passing through the compensator 15 rotated by 90 degrees around the optical axis OA with respect to the first parallel plane substrate 1,
It is corrected by producing astigmatism of equal amount and opposite sign, and enters the second homogeneous image/sensor 11. The light beam that has passed through the second dichroic mirror 14 similarly passes through the second parallel plane substrate 13 to have its astigmatism corrected, and then enters the third solid-state image sensor 12 . Second solid image 7/s1 by reflection from the back surface of the second parallel plane substrate 13
The incidence of ghost images on the second dichroic mirror 14 is prevented by providing the compensator 15 with a spectral characteristic that allows only the reflected light from the second dichroic mirror 14 to pass therethrough.

(Object of the invention) The object of the invention is to solve the following problems based on the prior invention:
An object of the present invention is to provide an improved color document reading device capable of reading a color document while adjusting the color balance arbitrarily.

(Structure of the Invention) The color document reading device according to the present invention rotates and displaces the first and second clock mirrors in the same direction and at the same angle within the plane of each of the first and second clock mirrors and the compensator hole. It includes a configuration for rotationally displacing the solid-state image/sensor in the same direction at an angle twice the rotational displacement angle. By rotating and displacing the first and second dichroic mirrors, the spectral characteristics can be changed, so that the color balance of a color original can be changed as desired when reading.

As shown in FIG. 1, a first dichroic mirror 2 is arranged so that the incident angle of light on the optical axis OA is θ within a radial plane, and a first solid-state image sensor 1 is positioned within a radial plane.
When the first solid-state image sensor 10 is rotated by 4 angles toward the 0 side, if the first solid-state image sensor 10 is rotated by 2α from its reference position of θ-45° in the same direction, the reflected light from the first dichroic mirror 2 is , can be incident on the first solid-state image sensor 10 at a right angle to perform correct imaging.

Similarly, when the second solid-state image sensor 11 is rotated by an angle α in the Tangier/7-plane plane as shown in FIG. If we make a rotational displacement in the same direction by 2α from
The reflected light from the dichroic mirror 14 can be incident on the second solid-state image/sensor 11'2 at right angles to form a correct image.

In this way, the first and second dichroic mirrors 2',
If the incident angle of 14 is changed, its spectral characteristics will change. For example, if the first dichroic mirror 2 reflects blue light, as shown in FIG. 3, if it is gradually rotated from an incident angle of 0°, the spectral characteristics will be It shifts to the wavelength side by about 60y++μ. Furthermore, if the second dichroic mirror 14 reflects red light, if the incident angle is changed from 0° to 60°, as shown in FIG.
Shift to/from the shorter wavelength side by μ. Therefore, by rotating and displacing the first and second dichroic mirrors 2 and 14 in the same direction and at the same angle, their spectral characteristics can be changed to the same degree, which improves the color balance of color originals. It can be changed arbitrarily. For example, if you want to reproduce a reddish color original in a standard tone, move the first and second dichroic mirrors 2.14 in a direction where the angle of incidence θ increases from 45° at the reference position t1t. The spectral characteristics may be shifted to the shorter wavelength side by rotationally displacing the light. On the other hand, if you want to reproduce a color original with a slight bluish tinge in a standard color tone - 1 Rotate the first and second dichroic mirrors 2.14 from their standard positions of 45° in a direction that reduces the incident angle θ. What is necessary is to shift the spectral characteristics to the longer wavelength side.

FIG. 5 shows an example of a mechanism for performing such rotational displacement. 2nd dichroic mirror 1
4 has its rotating shaft 17 so as to be rotationally driven by the second step motor 16 around the reflection point on its optical axis.
It is fixed to via a receiving member 18. A first gear 19 is fixed to the motor rotation shaft 17, and a second gear 21 fixed to another rotation shaft 20 meshes with this gear 19. A third gear 22 is fixed to this other rotating shaft 20, and a motor rotating shaft 17 is fixed to this third gear 22.
A fourth gear 24, which is fixed to a bearing 23 rotatably attached to the shaft, is engaged with the fourth gear 24. The fourth gear 24 has
The base of the arm 25 is fixed to the bearing 23 as a common rotational axis, and the arm 25 has a rotational axis 26 and a receiving member 27 in the middle thereof so that the compensator 15 can rotate around the reflection point on its optical axis. is attached to. The tip of the arm 25 has a second angle on the straight line between the centers of the motor rotation shaft 17 and the compensator rotation shaft 26.
A solid state image/sensor 11 is secured via a support 28. The receiving member 18 of the second dichroic mirror 14 and the receiving member 2 of the compensator 15
When the second dichroic mirror 14 and compensator 15 are in parallel, one side end of 7 is connected to the center distance between the motor rotation shaft 7 and the copy/setter rotation shaft 26 by means of a device. It is rotatably connected to the piece 29.

Since the tooth ratio of the first gear 19 and the fourth gear 24 is set to 21, when the second dichroic mirror 14 is rotated by a certain angle around the motor rotation shaft 17, the second solid degree image is generated. /sensor 11 (bow 1, also motor rotation shaft 17
Rotate around the center by twice that angle. The motor rotation shaft 17, the lower rotation shaft 26 and the support 2
8 are located on the same straight line, and the second dichroic mirror 1
4 and the compensator 15, together with the arm 25 and the connecting piece 29, constitute a parallel link mechanism, so that the optical axes can move in parallel to each other without shifting, and the incident angles on the respective optical axes can be kept the same. I can do it.

Note that the mechanism for rotationally displacing the first dichroic mirror 2 and the first solid-state image sensor 10 is the same as the one in FIG. 3 with the compensator 15 and its associated components removed, and is synchronously driven by another motor or the same motor. be done.

FIG. 6 shows a block diagram of an example of a control circuit for driving and controlling such a rotational displacement mechanism.

The first solid-state image processor 10 receives the reflected blue light and outputs a signal with a level corresponding to the amount of the incident light. The second solid-state image/sensor 11 receives the red reflected light and similarly outputs a signal at a level corresponding to the incident scene. The signals from these sensors 10 and 11 are input to window comparators 30 and 31, respectively, and are set to reference values ref 1 and 2.
When the input signal is larger than the reference value V1 or ■3, the high-level output becomes +hl", and the reference value V
When the input signal is smaller than 2 or V4, the low level output becomes d"'. Also, if V+ > input signal > V2, both the high level output and the low level output +tO"
becomes.

In this way, the level of the output signal from each solid-state image/sensor 10.11 can be determined by comparing it with the reference value Vrefl, 2 in each window comparator 30, 3'1. The output of each level dog or level small is sent to each AND cable 1-33 along with the pulse signal from the oscillator 32.
, 34, 35, and 36, and the first step motor 39 and the second step motor 4° are rotated clockwise or counterclockwise depending on the Shinzuki level through motors and drive circuits 37 and 38, respectively. Adjust the white balance.

FIG. 7 shows an example of a control block diagram when the color level is adjusted manually rather than automatically. In this case, you will need to check the tone of the reproduced color image before making the adjustment, but since the reproduced color image is based on the signals from each solid-state image processor, such manual adjustments are not necessary. In the end, it depends on the signal level of the solid-state imager/sugar. The pulse signal from the oscillator 41 is input to the control circuit 42 while the clockwise switch 43 or counterclockwise switch 44 connected to the control circuit 42 is kept on, and the motor drive circuit 45 is activated according to the number of pulses. The first step motor 39 and the second step motor 40 are driven synchronously, and the rotational displacement angle thereof is displayed on the angle display device 46. For example, if one clock signal corresponds to a rotational displacement angle of 1°, as shown in FIG. As the step motor 40 rotates 8 degrees clockwise from the reference position of 45 degrees, the angle display device 46 visually displays 8 degrees. Next, when the counterclockwise switch 44 is kept on and 10 pulse signals are output, the first step motor 39 and the second step motor 40 are moved 8 degrees from the previous displacement.
It is displaced 10° counterclockwise from the position 2, and 12° is displayed on the display device 46. In this way, manual color level adjustment is performed.

(Effects of the Invention) As described above, the color document reading robe according to the present invention has the following features:
The first and second solid-state image sensors are rotated at the same angle in the same direction in the plane of C, and the first and second solid-state image sensors are rotated at an angle twice as large as the rotational displacement angle. Since it is rotationally displaced in the direction, it is possible to read the correct signal by correcting the astigmatism and coast image caused by the dichroic mirror, and it is also possible to read the document at any color level by changing the spectral characteristics of the dichroic mirror. be able to.

[Brief explanation of the drawing]

First, Figures 2 and 2 are layout diagrams of the main optical systems in the vertical plane of a color document reading device showing an embodiment of the present invention.
Figure 1 shows the layout of the main optical system in the tangent plane perpendicular to Figure 1. Figure 3 shows the spectral characteristics of the blue-reflecting dichroic mirror at different angles of incidence. Figure 4 shows the red-reflecting dichroic mirror. 5 is a schematic configuration diagram showing an example of the rotational displacement mechanism of the present invention; FIG. 6 is a block diagram showing an example of the control method of the present invention; FIG. 7 is a spectral characteristic diagram at different incident angles of the mirror; , a block diagram showing another example of the control method according to the present invention, FIG. 8 is a timing diagram of the control method shown in FIG. FIG. 10 is an optical system layout diagram in a radial plane showing an example of
Figure 9 shows the arrangement of the optical system in the Tangien/Gill plane of the device.
FIG. 11 is a diagram showing the state of image formation on the first solid-state image sensor in the apparatus shown in FIGS. 9 and 10;
Figure 2 shows the second stage in the apparatus shown in Figures 9 and 10.
FIG. 13 is a diagram showing the state of image formation on a solid-state image sensor. FIG. 13 is a diagram showing the arrangement of light and optical systems in the radial plane in the prior invention. FIG. FIG. 3 is an optical system layout diagram. 9. Imaging lens 2. First dichroic mirror 10.
First solid-state image sensor 11 ・Second solid-state image sensor 12...Third solid-state image sensor 14 Second
Dikroitsuku Mirror 15. Compensator Ryo 6 z Fortune 4 Father Rokuryu (□yt!, ll)

Claims (1)

[Claims] An apparatus for reading a color original by color-separating the color original into three primary colors through an imaging lens and a color separation optical system and forming images on first, second, and third solid-state image sensors, respectively, the apparatus comprising: A color separation optical system includes a first surface reflection dichroic mirror arranged so that the incident angle on the optical axis is θ in a radial plane, and a first dichroic mirror with a surface reflection arranged so that the incident angle on the optical axis is θ in a radial plane, and an incident angle on the optical axis in a tangential plane perpendicular to the radial plane. Same angle θ
a second dichroic mirror with a surface reflection arranged so that a compensator disposed parallel to the second dichroic mirror between the solid-state image sensor and a second solid-state image sensor that receives reflected light therefrom; the first dichroic mirror, the second dichroic mirror, and the compensator; are rotationally displaced in the same direction and at the same angle within their respective planes, and the first solid-state image sensor that receives the reflected light from the first dichroic mirror and the second solid-state image sensor are and means for rotationally displacing in the same direction at twice the angle.