JPH0458130A - Method and device for measuring eccentricity of lens surface - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and apparatus for measuring the eccentricity of an optical lens including a toroidal surface with different curvatures in the vertical and horizontal directions used in laser printers, etc. It is applicable to a lens alignment device, an inspection device, etc. during lens assembly.

[Prior Art] Conventionally, as a device for measuring the amount of lens eccentricity, (1) an index image by a collimator lens is projected onto the apparent center of curvature of each measurement surface of the lens to be measured, and the target image is projected around the measurement reference axis. The lens rotation method (
2) The amount of eccentricity can be measured in the same way as in (1) by fixing the lens to be measured, moving and adjusting the corner cube provided in the collimator system that projects the index, and changing the image position of the index.
This is an improvement on the Zeiss method and the lens rotation method in (1).
An image rotator system is known in which a rotatable image rotator is provided between a collimator system and a lens to be measured, and the amount of eccentricity can be measured by fixing the lens to be measured.

In the Zeiss method (2), the number of times of transmission and reflection through the beam splitter is large, and the amount of light is extremely reduced, so the method (2) or (3) is adopted in the field.

[Problems to be Solved by the Invention] In the known measurement of the amount of lens eccentricity, it is suitable when the lens surface of the lens to be measured is a spherical surface, and the lens to be measured includes a toroidal surface (toric surface) and a cylindrical surface. It is difficult to measure the amount of eccentricity of the lens surface when the target is .

An object of the present invention is to provide a method and apparatus suitable for measuring the amount of eccentricity of a lens surface with respect to a lens including a toroidal surface or a cylindrical surface, and to easily and accurately measure the amount of eccentricity. A method and apparatus are provided that allow automatic measurements.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention measures the position of the reflected light image of the lens surface in a lens to be measured including a toroidal surface, and calculates the amount of eccentricity of the lens surface. In the measurement method, the objective lens is placed on a stage that can be moved and adjusted in the X-axis direction, the lens to be measured is placed on a rotation stage, and the lens to be measured is rotated at an appropriate angle for each lens surface of the lens to be measured. The objective lens is moved to focus the index on the changing apparent center of curvature of the lens surface of the lens to be measured in one direction, and the reflected image is measured based on the coordinate position on the two-dimensional sensor. This method is characterized in that the amount of eccentricity of the lens surface of the lens to be measured is measured by a computer.

The present invention also provides a lens surface eccentricity measuring device that measures the position of a reflected light image on a lens surface including a toroidal surface and calculates the amount of eccentricity, in which an index is set at the apparent center of curvature of the lens to be measured. X to match the focus
An objective lens placed on a stage that can be adjusted to move in the axial direction, a rotary stage on which the lens to be measured is placed and can be rotated by a predetermined angle, and an image of the reflected image from the lens surface of the lens to be measured. It consists of a two-dimensional sensor that detects the position, and is characterized in that the amount of eccentricity of the lens surface of the lens to be measured is measured by a microcomputer.

[For production]

According to the configuration of the present invention, for a toroidal surface, the lens to be measured is rotated by 90 degrees using a rotation stage, and the index is imaged at the apparent center of curvature by adjusting the objective lens.
The reflected light image is formed on a two-dimensional sensor, and the eccentricity in the vertical and horizontal directions can be easily measured from the position of the reflected light image.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a configuration diagram of an embodiment of the present invention.

A half mirror 3 is arranged on the measurement axis XX, and the index 2 provided with the slit-shaped opening 2A shown in FIG. The collimator lens 4, objective lens 5, and mirror 6 on
, 73...

The lens to be measured 7 is placed on a rotating pulse stage 9, and when measuring the amount of eccentricity of a toroidal surface, etc.
It rotates 360 degrees in degree intervals, and in the case of a spherical surface, for example, 1
Measurement can be performed by rotating 360 degrees at 20 degree intervals.

The objective lens 5 includes an X-axis pulse stage 10 that can move the objective lens 5 in the measurement axis XX direction in order to focus the image of the index 2 on the apparent center of curvature of the measurement lens surface of the lens 7 to be measured. It is placed on.

At a position opposite to the half mirror 3 on the measurement axis X-x, a two-dimensional sensor 8 is arranged to detect an index image reflected from the measurement lens surface of the lens 7 to be measured.

The rotation pulse stage 9 and the X-axis pulse stage 10 are driven by a controller 13 connected to a microcomputer 12.

Furthermore, the two-dimensional sensor 8 is connected to a microcomputer 12 via an A/D converter 11.

By the way, a method for measuring the amount of eccentricity of the toroidal surface 71, which is the first surface of the lens 7 to be measured shown in FIG. 4, will be explained.

The rotating pulse stage 9 in FIG.
A lens to be measured 7 having a toroidal surface 7.I, 7□, 73... is supported. First, since the apparent centers of curvature in the vertical (vertical) direction and the horizontal (horizontal) direction are different,
The apparent center of curvature P of the toroidal surface 71 in the longitudinal (vertical) direction. The X-axis pulse stage IO moves the objective lens 5 by the microcomputer 12 and controller 13 so that the objective lens 5 is focused on

The focus of the objective lens 5 is adjusted, and a slit-shaped aperture 2A is formed.
Index 2 is the apparent center of curvature P in the vertical (vertical) direction. At the same time, the reflected light image from the toroidal surface 7□ returns from the mirror 6 through the objective lens 5 and the collimator lens 4, passes through the half mirror 3, and is sent to the two-dimensional sensor 8.
An optical image Pl+ is formed thereon.

The position of this optical image Pl+ on the two-dimensional sensor 8 is
The A/D converter tA device 11 and microcomputer 12 display the coordinate position a1.

Next, the lens 7 to be measured is controlled by the microcomputer 12 and the controller 13, and the rotating pulse stage 9 is
The toroidal surface 7I of the lens 7 to be measured is set from the vertical direction to the horizontal direction.

Then, as in the case described above, the X-axis pulse stage 10 is controlled by the microcomputer 12 and the controller 13 so that the objective lens 5 is focused on the apparent center of curvature PO2 in the lateral (horizontal) direction of the toroidal surface 71. The lens 5 is moved, and the reflected light image forms a light image P1□ on the two-dimensional sensor 8. The position of this optical image PI2 is represented on the two-dimensional sensor 8 by a coordinate position a2.

Furthermore, the lens 7 to be measured is rotated 90 degrees and rotated from the horizontal direction to the vertical direction, and then rotated 180 degrees from the initial position in the vertical (vertical) direction of the toroidal surface 7 degrees, so that the index 2 continues (vertical). ) apparent center of curvature P in the direction. 3 and formed on the two-dimensional sensor 8, coordinate values Ha of the light image P,
get.

Finally, the lens 7 to be measured is rotated 90 degrees again and rotated from the vertical direction to the horizontal direction, and the toroidal surface 7. Next to (
Rotate 180 degrees from the horizontal (horizontal) position and move index 2 horizontally (
apparent center of curvature P in the horizontal) direction. From the optical image P14 formed on the two-dimensional sensor 8, the coordinate position a4 of the optical image PI4 is obtained.

The coordinate values obtained in relation to the apparent center of curvature in the vertical (vertical) direction as described above? i23+, a, and t*
Coordinate positions a2 and a4 obtained in relation to the apparent center of curvature in the <horizontal) direction, the radius of curvature Ry1 in the vertical direction of the toroidal surface 7I, and the radius of curvature Rz in the horizontal direction,
From this, the first surface, the toroidal surface 7. Eccentricity αy1
, az1 are as follows.

cry+ = (at-83)/(2xRy+) αZ
+ = (az-34)/(2XRz+) Toroidal surface and other lens surfaces 7 after the second surface of the lens 7 to be measured
Regarding □, 73, etc., the amount of eccentricity of each lens surface can be measured in the same manner.

The amount of eccentricity of the lens surfaces after the second surface is calculated by excluding the amount of eccentricity of the lens surface located in front of it. for example,
In the case of the third lens surface, the amount of eccentricity between the first and second surfaces is removed.

[Effects] With the configuration of the present invention, the amount of eccentricity can be automatically measured separately in the vertical (vertical) direction and the horizontal (horizontal) direction on the lens surface of the lens to be measured. This has the effect of easily and accurately measuring the eccentricity of a toroidal surface that has different radii of curvature in each direction.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the measurement of eccentricity of the lens surface according to the present invention, Fig. 2 is an enlarged view of the index used in the present invention, and Fig. 3 is a diagram showing the relationship between each optical image and the coordinate position on the two-dimensional sensor. FIG. 4 is a perspective view showing an example of a lens to be measured. DESCRIPTION OF SYMBOLS 1...Lamp, 2...Indicator, 2 people...Slit-shaped opening, 3...Half mirror 14...Collimator lens, 5...Objective lens, 6...Mirror, 7...・・・
Lens to be measured, 7I, 7□, 7. ...lens surface,
8... Two-dimensional sensor, 9... Rotating stage, 10...
・・X-axis stage, 11・・A/D converter, 12・
...Microcomputer, 13...Controller,
14...Display.

Claims (2)

[Claims] (1) In the lens surface eccentricity measurement method, which measures the position of the reflected light image on the lens surface including a toroidal surface and calculates the eccentricity amount, the objective lens is placed on a stage that can be moved and adjusted in the X-axis direction. The lens to be measured is placed on a rotation stage, and the lens to be measured is rotated by an appropriate angle for each lens surface of the lens to be measured, and the apparent curvature of the lens surface of the lens to be measured changes in one direction. In the center position,
A lens surface characterized by moving an objective lens so as to focus on an index, and measuring the eccentricity of a lens surface of a lens to be measured using a microcomputer based on the coordinate position of the reflected image on a two-dimensional sensor. How to measure eccentricity. (2) In a lens surface eccentricity measurement device that measures the position of the reflected light image on the lens surface including a toroidal surface and calculates the amount of eccentricity, the index is focused on the apparent center of curvature of the lens to be measured. An objective lens placed on a stage that can be moved and adjusted in the X-axis direction so as to match, a rotary stage on which the lens to be measured is placed and can be rotated by an appropriate angle, and the lens of the lens to be measured. 1. A lens surface eccentricity measuring device comprising a two-dimensional sensor that detects the position of a reflected image from a surface, and measuring the amount of eccentricity of the lens surface of a lens to be measured using a microcomputer.