JPH0468856A - Magnification correcting mechanism for optical device - Google Patents

Abstract

PURPOSE:To easily correct magnification error caused by the focal distance error of an image formation lens while saving labor by forming a mirror to be bent and bending the mirror to change the magnification of an image to be formed in a photodetecting means. CONSTITUTION:A second mirror 11 is formed so as to be bent for displacing a central part 11B to both ends 11A in the lengthwise direction. On the face of the image formation lens side at the both ends 11A of the mirror 11, an abutting means 13 is installed a case 12, and at the part of the case 12 facing to the central part 11B in the lengthwise direction of the mirror 11, a block 14 is installed. Then, an adjusting screw 15 to be abutted to the center of the mirror 11 in the lengthwise and height-wise directions is screwed to the block 14. Next, in order to correct the magnification error caused by the focal distance error of an image formation lens 7, the adjusting screw 15 is operated and the central part 11B of the mirror 11 is displaced and bent in the direction of the image formation lens so as to change the curvature of the mirror 11.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an optical device used in facsimiles, scanners, etc. The present invention relates to a magnification correction mechanism.

(Prior Art) For example, an image reading section of a facsimile uses an optical device that guides a light beam corresponding to one piece of image information to a light receiving means.

FIG. 4 shows a schematic side view of an optical device in an image reading section of a facsimile.

1 is a glass plate on which the original 2 is placed; 3 is a reading light source such as a halogen lamp placed on the bottom side of the glass plate 1; 4 is placed opposite the irradiation position of the light source 3 on the original 2; A second mirror 5 is installed in the reflection direction of the first mirror 4 to change the direction of the reading light in the horizontal direction.

Further, an imaging lens 7 is disposed on the reflection optical path of the second mirror 5, and a light receiving means (CCD) 8 is disposed at the location where the image is formed by the imaging lens 7.

Then, the light receiving means 8 converts the reading light into electrical image information for each line of the original, and by converting into image information for each line and transporting the original, or by moving the entire optical device, one sheet is processed. The entire document is read and output.

On the other hand, the imaging lens 7 has a focal length error within a certain range, and when assembled into an optical device, the magnification error due to the focal path H error of the imaging lens 7 is corrected to eliminate errors in the reading width, etc. There is a need to.

For example, if the focal length of the imaging lens 7 is slightly longer than the designed value due to a focal length error, it is necessary to shorten the distance between the imaging lens 7 and the light receiving element 8. However, if this distance is shortened, the focus will be on the light receiving means 8, but the magnification will be reduced.

Conventionally, the magnification has been corrected by moving the second mirror 5 and changing the optical path length from the imaging lens 7 to the document 2.

A support structure for the second mirror 5 for changing the optical path length will be explained with reference to FIGS. 5 and 6.

As shown in FIG. 5, two adjustment screws 9A and 9B are provided on the back side of one end 5A of the second mirror 5.

Further, on the back side of the other end 5B, as shown in FIG. 5, one adjustment screw 9C is arranged, and furthermore, on the front side of the second mirror 5, there is a spring 9D that biases the second mirror 5 to the back side. The second mirror 5 is supported by these three adjusting screws 9A, 9B, 9C and a spring 9D.

Then, use the adjusting screws 9A, 9B, and 9C to adjust the imaging lens 7.
The magnification error caused by the focal length error of the imaging lens 7 is corrected by moving the second mirror 5 in a direction toward and away from the original 2 and changing the optical path length between the original 2 and the imaging lens 7.

(Problem to be Solved by the Invention) However, the work using the adjustment screws 9A, 9E, and 9C involves operating the three screws individually, changing the angle of the second mirror 5, and moving the entire second mirror 5 to the imaging lens. 7, the adjustment work is extremely troublesome and time-consuming.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a correction mechanism that can easily correct magnification errors due to focal length errors of an imaging lens without requiring much time and effort. It is about providing.

(To solve the problem 1) In order to achieve the above object, the present invention forms a mirror so that it can be curved, and includes a curving means for curving the mirror so as to change the magnification of the image formed on the light receiving means. It is characterized by having been provided.

(Function) By curving the mirror, the light beam is focused or diffused by the mirror, thereby correcting the magnification error due to the focal length error of the imaging lens.

(Example) Hereinafter, an example in which an example of the present invention is applied to the second mirror 5 shown in FIG. 4 will be described.

Fig. 1 is a perspective view of the correction mechanism according to the present invention, and Fig. 2 is a perspective view of the correction mechanism according to the present invention.
A side view is shown.

Reference numeral 11 denotes a second mirror, and the second mirror 11 is formed so as to be curved so that its central portion 11B is displaced with respect to both ends 11A in the longitudinal direction.

As the second mirror 11, a mirror made of metal, glass, or the like can be used.

Abutment members 13 are provided upright from the case 12 on the surfaces of the seven imaging lenses at both ends 11A of the second mirror 11, and the second
Case 12 facing central part 11B of mirror 11 in the longitudinal direction
A block 14 is erected at the portion, and an adjustment screw 15 that abuts the center of the second mirror 11 in the longitudinal direction and the height direction is screwed into the block 14.

The angle and position of the second mirror 11 are fixed by the two contact members 13 at both ends 11A and the adjustment screw 15 at the center, and the adjustment screw 15 moves the center of the second mirror toward the imaging lens 7 side. The second mirror is configured so that the angle of the second mirror does not change even if the second mirror is displaced and curved.

In this embodiment, the design value of the focal length error of the imaging lens 7 is predetermined so as to be within a positive range.

In the above configuration, in order to correct the magnification error due to the focal length error of the imaging lens 7, as shown by the virtual line in FIG.
1B is displaced in the direction of the imaging lens 7 and curved.

Due to the curvature of the second mirror II, both sides of the reading light incident on the second mirror 11 expand in the longitudinal direction of the second mirror 11, as shown by the virtual line A in FIG. The formed image is reduced compared to when the second mirror 11 is a straight line.

Therefore, by curving the second mirror 11, the reading light is focused by the second mirror 11, in other words, the curvature of the second mirror 11 is changed, thereby correcting the magnification error due to the focal length error of the imaging lens 7. be done.

According to this embodiment, since the reading light is focused by the second mirror 11 without changing the optical path length, the imaging lens 7 can be adjusted efficiently by a simple operation of rotating the - adjustment screw I5. The magnification error due to the focal length error can be corrected steplessly, and since the angle of the second mirror 11 in the height direction is determined by the abutment member 13, there is no reading deviation due to optical axis deviation. It is also possible to correct distortion of the imaging lens 7 by curving the second mirror 11.

In the embodiment, a case has been described in which the second mirror 11 is curved convexly with respect to the imaging lens 7, but if the focal length error of the imaging lens 7 is within a negative range, the second mirror 11 If the focal length error of the imaging lens 7 is in a plus and minus range, the second mirror 11 may be curved in both a convex and a concave shape.

Furthermore, the present invention is applicable not only to facsimile machines but also to various optical snowmaking systems used in copying machines, scanners, and the like.

(Effects of the Invention) As explained above, according to the magnification correction mechanism according to the present invention,
Since the optical path length between the original and the imaging lens is not changed and the light beam is focused or diffused by a mirror, magnification errors due to focal length errors of the imaging lens can be easily corrected with a simple configuration. be able to.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of the present invention, Fig. 2 is a side view thereof, Fig. 3 is a plan view thereof, Fig. 4 is a schematic side view of the image reading section of a facsimile, Figs. FIG. 6 is a side view of the support structure for the second mirror. In the figure, 2 is a document, 3 is a light source, 4 is a first mirror 5, 11 is a second mirror, 7 is an imaging lens, 8 is a light receiving means, 13 is a contact member, 14 is a block, and 15 is an adjustment screw. be. Patent applicant Agent: Asahi Optical Industries Co., Ltd.
Patent Attorney No 1) Shigeru Figure 2 Figure O Figure B

Claims (1)

[Scope of Claims] An optical device in which the direction of a light beam corresponding to image information is changed by a mirror, and the image is formed on a light receiving means by an imaging lens, wherein the mirror is formed to be bendable, and the image is formed on the light receiving means. A magnification correction mechanism in an optical device, comprising: a curving means for curving the mirror so as to change the magnification of an image.