JPH09170964A - Lens decentering measuring equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable measurement of the decentering amount of a lens system, by installing a lens movement detector which detects the lens movement amount in a lens system to be inspected, and a luminous flux controller. SOLUTION: A luminous flux reflected from a lens system 5 to be inspected is converged on an optical image position detector 2 with an optical system 3, and the position is detected as an optical image, thereby measuring the decentering of the lens system 5. When the lens system 5 moves, it is necessary to change the convergency of the luminous flux outputted from the optical system 3 in accordance with the lens movement amount, so that the movement amount of the lens system 5 is detected with a lens movement detector 7, and the convergency of the optical system 3 is controlled on the basis of detected result, with a luminous flux controller 6 as a controlling means. The fluctuation of the optical image in accordance with the decentering amount of the lens system 5 is displayed with a display 1, and the decentering amount of the lens system 5 is measured by the fluctuation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens eccentricity measuring device for measuring the eccentricity of, for example, a zoom lens having a movable lens unit inside.

[0002]

2. Description of the Related Art A lens eccentricity measuring device of this type is known, for example, the one disclosed in Japanese Patent Application Laid-Open No. 4-289426, and the lens eccentricity measuring device of the publication will be outlined with reference to FIG.

This lens eccentricity measuring device is provided with a lens eccentricity measuring device 100 for measuring the eccentricity of the lens 105 to be measured. The lens eccentricity measuring device 100 includes a laser oscillator 101 that oscillates a randomly polarized laser, a beam splitter 102, a first imaging lens 103, a second imaging lens 104, a third imaging lens 108, and a two-dimensional lens. The point image position detection sensor 109 is provided.

The optical axis of the parallel beam laser light emitted from the laser oscillator 101 coincides with the reference axis 106 of the lens under test 105, and the beam splitter 102,
The first imaging lens 103 and the second imaging lens 104 are arranged on this optical axis. The laser light emitted from the laser oscillator 101 passes through the beam splitter 102,
It is converged by the first imaging lens 103 and becomes a point light source aiming light source 107. The light emitted from the aiming light source 107 is converged by the second imaging lens 104 and enters the lens under measurement 105.

In this way, the laser oscillator 101, the beam splitter 102, the first imaging lens 103 and the second
The imaging lens 104 constitutes a projection optical system that projects the light of the aiming light source 107 toward the lens under measurement 105.

The light reflected in the auto collimation state on the specific surface to be measured in the lens to be measured 105 is
It passes through the second imaging lens 104 and the first imaging lens 103, is reflected by the beam splitter 102, is converged by the third imaging lens 108, and is incident on the two-dimensional point image position detection sensor 109. As a result, the point image of the aiming light source 107 is formed on the two-dimensional point image position detection sensor 109.

The two-dimensional point image position detection sensor 109 is connected to a signal processing circuit (not shown), and this signal processing circuit outputs from the two-dimensional point image position detection sensor 109 according to the position of the point image of the aiming light source 107. The amount of eccentricity of the measured lens 105 is detected based on the signal obtained.

[0008]

However, in the above-mentioned prior art, since the projection light flux of the projection optical system is calculated and set in advance, a movable lens portion is provided inside such as a zoom lens. There is a problem that it is difficult to measure the amount of eccentricity of the lens.

It is an object of the present invention to solve the above problems and to provide a lens eccentricity measuring device capable of measuring the amount of eccentricity of the lens system having a moving lens portion inside. is there.

[0010]

According to the first aspect of the present invention,
A light source, an optical system capable of varying the degree of convergence of a light beam from the light source, a light image position detecting means for detecting a light image position of the light beam projected on the lens system to be inspected and reflected, and the light image position A lens eccentricity measuring device having display means for displaying the optical image position detected by the detecting means, wherein the lens movement detecting means detects the amount of lens movement in the lens system to be tested, and the output of the lens movement detecting means. And a control unit that changes the degree of convergence of the optical system.

According to a second aspect of the present invention, a light source, an optical system capable of varying the degree of convergence of a light beam from the light source, and an optical image position of the light beam reflected by projecting this light beam onto a lens system to be detected are detected. A lens eccentricity measuring device having an optical image position detecting means and a display means for displaying the optical image position detected by the optical image position detecting means, wherein the lens movement detection detects the amount of lens movement in a lens system to be inspected. Means, the lens movement amount of the lens system to be detected detected by the lens movement detection means, and the optical image position detected by the optical image position detection means, are displayed on the display means, and the lens movement detection is performed. And a control means for changing the degree of convergence of the optical system according to the output of the means.

FIG. 1 is a conceptual diagram for explaining a lens decentering measuring apparatus according to claim 1 of the present invention. In FIG. 1, the light flux emitted from the light source 4 is projected onto the lens system 5 to be inspected by the optical system 3, and the light flux reflected from the lens system 5 to be inspected is condensed on the optical image position detector 2 by the optical system 3. Then, the eccentricity of the lens system 5 to be measured is measured by forming an optical image and detecting the position thereof. When the lens system 5 to be inspected moves, for example, in the direction of the arrow in FIG.
Since it is necessary to change the degree of convergence of the light flux emitted from the optical system 3, the amount of movement of the lens system 5 to be detected is detected by the lens movement detector 7, and the optical system 3 is controlled by the light flux controller 6 which is the control means based on the detection result. Control the convergence degree of. Then, the shake of the optical image based on the amount of eccentricity of the lens system 5 to be inspected at this time is displayed on the display unit 1 which is a display means, and the amount of eccentricity of the lens system 5 to be inspected is measured by this shake.

In the lens eccentricity measuring device according to the second aspect,
By using the output of the lens movement detector 7 described above as the input of the display 1, the eccentricity amount corresponding to the movement amount of the lens system 5 to be tested can be displayed. Thereby, the movement of the eccentric amount due to the movement of the lens system 5 to be tested can be measured.

[0014]

Embodiments of the present invention will be described in detail below.

[First Embodiment] FIG. 2 shows a lens decentering measuring apparatus according to a first embodiment of the present invention. The lens eccentricity measuring device shown in FIG. 2 includes a laser diode 13 which is a light source,
The degree of convergence of the light beam incident from the laser diode 13 through the lens 12 is changed and projected on the lens system 5 to be inspected, and the degree of convergence of the reflected light beam from the lens system 5 to be inspected is varied. The optical system 30 configured as described above, the position sensor 20 that is an optical image position detecting unit that detects the optical image position of the light beam projected from the optical system 30 and reflected by the lens system to be inspected, and the position sensor 20. An oscilloscope 8 which is a display means for displaying the detected optical image position of the light flux, a motor driving device 17 and a motor 18 for moving the lens system 5 to be inspected, and a motor 18 which are connected to the motor 18 and respond to the rotation of the motor 18. It also has a rotary encoder 19 as a lens movement detecting means for detecting the movement amount of the lens system 5 to be tested.

The optical system 30 includes a beam splitter 10
And a lens 11 arranged on the side of the lens system 5 to be inspected with respect to the beam splitter 10 and a lens 9 arranged on the position sensor 20 side with respect to the beam splitter 10, and are connected to the lens 11 via a ball screw. By driving the stage 14 by the lens drive motor 15,
This lens 11 is moved in the direction of the arrow shown in FIG. 1 to change the degree of convergence of light of the optical system 30.

The lens 12, the beam splitter 10,
The lens 11 is arranged so as to project the light flux emitted from the laser diode 13, which is a light source, onto the lens system 5 to be tested. The lens 11 is arranged so as to face the lens system 5 to be tested. Further, the lens 9 is at a position where the reflected light from the lens system 5 to be inspected can be projected onto the position sensor 20, that is,
Usually, it is arranged between the position sensor 20 and the beam splitter 10. The position sensor 20 is a position sensor manufactured by a semiconductor process. Oscilloscope 8
Is composed of a storage-type oscilloscope having an internal memory and displays output data of the position sensor 20.

The lens system 5 to be inspected is a lens such as a camera lens having a movable lens inside. The motor 18 is connected to a moving mechanism (not shown) that moves the lens system 5 to be tested, and a rotary encoder 19 is arranged at one end of a driving shaft of the motor 18.

Further, the output from the rotary encoder 19 is inputted to a computer 16 as a control means and subjected to position calculation processing, and the motor 15 is driven according to the calculation processing result.

Next, the operation of the lens eccentricity measuring device described above will be described. The light beam emitted from the laser diode 13 enters the lens 12, the light beam is expanded, and then enters the beam splitter 10. The beam splitter 10 has a function of separating the incident light flux and a reflected light flux from a lens system 5 to be tested, which will be described later, and a laser diode 13
The light flux from is reflected by the beam splitter 10 and enters the lens 11. Then, the light flux converged by the lens 11 enters the measurement surface 5a of the lens system 5 to be tested.

At this time, the lens 11 is moved to the moving motor 1
5. By moving the stage 14 so that the light beam is incident perpendicularly to the measurement surface 5a of the lens system 5 to be tested,
It is possible to establish an autocollimation relationship in which the reflected light from the measurement surface 5a goes backward in the optical path at the time of incidence.

The light beam that has gone backwards through the optical system 30 is reflected by the lens 11
Then, the light passes through the beam splitter 10, is condensed by the lens 9, is received by the position sensor 2, and becomes an optical image. The position sensor 20 has a function of detecting the position of the optical image,
When the measurement surface 5a of the lens system 5 to be inspected is decentered from the optical axis, the position of the optical image is obtained and the deviation of the lens system 5 to be inspected from the optical axis is detected. When measuring the test lens system 5 having a lens moving part such as a camera lens, the measurement surface 5a of the test lens system 5 moves on the optical axis, so that the lens 11 also moves along with the movement of the measurement surface 5a. Move to maintain the autocollimation relationship.

Therefore, the motor 18 is rotated by the motor driving device 17 and at the same time the rotary encoder 19 is driven.
The number of rotations of the motor 18 is detected (counted) by the
While measuring the moving distance of a, the computer 16 performs geometric ray tracing based on the measurement result, calculates the moving value of the measurement surface 5a so as to be in the above-described autocollimation state, and drives the motor 15, The position of the lens 11 is controlled via the stage 14. With the movement of the measurement surface 5a, the oscilloscope 8 moves the lens system 5 under test.
The amount of eccentricity due to the movement error of the movable part of is displayed.

According to the first embodiment, by using the position sensor 20, the amount of eccentricity of the lens system 5 to be tested can be detected in real time, and the amount of eccentricity accompanying the movement of the lens system 5 to be tested can be accurately measured. it can.

[Second Embodiment] FIG. 3 shows a lens decentering measuring apparatus according to a second embodiment of the present invention. In the lens eccentricity measuring device of the second embodiment, elements having the same functions as those of the lens eccentricity measuring device of the first embodiment are designated by the same reference numerals.

The lens eccentricity measuring device according to the second embodiment is C
The image pickup camera 21 which is a light image position detecting means composed of a CD camera or the like is arranged at the image forming position of the lens 9 of the optical system 30, and the computer 22 is a CR which is a displaying means.
Connected to the T display 23, and further connected to the imaging camera 21
The feature is that the image pickup signal of 1 is taken into the computer 22 via the frame memory 24. The other components are the same as those in the first embodiment, and thus the description thereof will be omitted.

As in the case of the first embodiment, the light beam emitted from the laser diode 13 is projected onto the lens system 5 to be inspected through the lens 12, the beam splitter 10 and the lens 11, and the reflected light beam is an image pickup camera. It is condensed on 21 and becomes an optical image.

In order to detect the position of the optical image on the image pickup camera 21, the computer 22 temporarily converts the video signal into a digital signal in the frame memory 24 and stores it as an image signal. The computer 22 performs a binarization process from the image signal stored in the frame memory 24 to determine the focus position, and then obtains the center of gravity of the focused light image.
Further, as in the case of the first embodiment, the computer 22 takes in the movement distance signal of the lens system 5 to be inspected, which is the output of the rotary encoder 19, controls the motor 15, and at the same time, the focus position obtained from the center of gravity. On the vertical axis and the moving distance signal on the horizontal axis.
Display on screen 3. Other operations are the same as in the case of the first embodiment.

Since the eccentricity amount of the optical image and the moving distance of the moving lens portion of the lens system 5 to be tested can be displayed in correspondence with the display 23, the eccentric movement due to the moving accuracy of the moving lens portion can be accurately measured.

[Third Embodiment] In the configuration of the third embodiment of the present invention, although not shown, the rotary encoder 19 in the second embodiment is deleted, and the position of the image pickup camera 21 is set to the position where the light image is condensed. It is arranged at the focused position. Other configurations are similar to those of the third embodiment.

As a function of the third embodiment, in order to correspond to the lens movement of the lens system 5 to be inspected, the computer 22 image-processes the degree of focusing on the image pickup camera 21, and the lens 11 is always brought into the autocollimation relation. Is to control.

The degree of light condensing on the image pickup camera 21 changes as the measurement surface 5a of the lens system 5 to be moved moves and the autocollimation relationship collapses. The detection of the degree of focusing can be obtained by taking in the image signal from the imaging camera 21 by the frame memory 24, binarizing the image signal, and measuring the diameter or the perimeter of the optical image data in the image signal.

Further, when the image pickup camera 21 is placed at the normal focusing position, it is not known in which direction the movable part of the lens system 5 to be moved has been moved. Therefore, the image pickup camera 21 is defocused back and forth to some extent. To place.

The computer 22 feedback-controls the movement of the lens 11 so that the spot diameter of the optical image always becomes a predetermined value, so that the image pickup camera 21 can be moved even if the measurement surface 5a of the lens system 5 to be inspected moves. The spot diameter is always constant, so that the autocollimation relationship can be maintained. Other actions are similar to those of the second embodiment.

According to the third embodiment, since the rotary encoder 19 is not used, it is possible to measure the amount of eccentricity due to the lens movement with the optical system 30 attached to the main body of the image pickup camera 21.

[0036]

According to the first aspect of the present invention, it is possible to provide a lens eccentricity measuring device capable of measuring the amount of lens eccentricity even in a lens system to be tested whose convergence can be varied.

According to the second aspect of the present invention, the amount of lens eccentricity is displayed by associating and displaying the amount of movement of the lens system under test and the amount of eccentricity associated with the change in the degree of convergence due to the movement of the lens system under test. It is possible to provide a lens eccentricity measuring device that can perform accurate measurement.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration of a lens eccentricity measuring device of the present invention.

FIG. 2 is an optical layout diagram showing the configuration of Embodiment 1 of the lens decentering measuring apparatus of the present invention.

FIG. 3 is an optical layout diagram showing a configuration of Embodiment 2 of the lens decentering measuring apparatus of the present invention.

FIG. 4 is an optical layout diagram showing a conventional lens eccentricity measuring device.

[Explanation of symbols]

 1 Display Device 2 Optical Image Position Detector 3 Optical System 4 Light Source 5 Test Lens System 6 Optical Controller 7 Lens 8 Otssiroscope 9 Lens 10 Beam Splitter 11 Lens 12 Lens 13 Laser Diode 14 Stage 15 Motor 16 Computer 17 Motor Drive Device 18 Motor 19 Rotary encoder 24 Frame memory

Claims (2)

[Claims] 1. A light source, an optical system capable of varying the degree of convergence of a light beam from the light source, and an optical image position detecting means for detecting the optical image position of the light beam projected onto the lens system to be inspected and reflected. A lens eccentricity measuring device having a display means for displaying the optical image position detected by the optical image position detecting means, the lens movement detecting means for detecting a lens movement amount in a lens system to be tested, and the lens movement detecting means. A lens eccentricity measuring device comprising: a control unit that changes the degree of convergence of the optical system according to the output of the detection unit. 2. A light source, an optical system capable of varying the degree of convergence of a light beam from this light source, and an optical image position detecting means for detecting the optical image position of the light beam projected onto this lens system under test and reflected. A lens eccentricity measuring device having a display means for displaying the optical image position detected by the optical image position detecting means, the lens movement detecting means for detecting a lens movement amount in a lens system to be inspected, and the lens movement The lens movement amount of the lens system to be detected detected by the detection means and the optical image position detected by the optical image position detection means are captured and displayed on the display means, and the optical movement is performed by the output of the lens movement detection means. A lens eccentricity measuring device comprising: a control unit that changes the degree of convergence of the system.