Asphere measurement method and apparatus

Abstract

Disclosed is an asphere measurement method capable of measuring the surface deviations and the surface tilts with high accuracy even when an asphere to be measured does not have the wedge-shaped flat portion. An optical interferometer using a first interferometer (1A) and a second interferometer (1B) acquires shape data of the center portions of a first lens surface (91) and a second lens surface 92 of an aspheric lens (9). From the respective shape data, respective position data of a first umbilical point P 1 , a first center of curvature, and a first axis of the first lens surface (91) are acquired in a first measurement coordinate system. Simultaneously, respective position data of a second umbilical point P 2 , a second center of curvature, and a second axis of the second lens surface (92) are acquired in a second measurement coordinate system. On the basis of these position data and the relative position relation between the first measurement coordinate system and the second measurement coordinate system, surface deviations and surface tilts of the aspheric lens (9) are acquired.

Description

technical field [0001] The present invention relates to an aspherical device for measuring the relative deviation (surface deviation and surface deflection) of the front and back surfaces of an aspherical body such as an aspheric lens used in various optical devices such as digital cameras and optical sensors. Spherical measurement method and device. Background technique [0002] In the case of manufacturing an aspherical lens by mold molding, due to the relative positional deviation of the molding dies, the surface deviation of the aspheric lens formed (the distance between the rotation axes of the two lens surfaces constituting the aspheric lens) Relative positional deviation) or surface skew (relative inclination deviation of the rotation axes of the two lens surfaces) may exist. It is difficult to completely eliminate such surface deviation or surface deviation in the mechanism of the mold, and it becomes the rotational asymmetry of the aberration (especially coma aberr...

AI Technical Summary

Problems solved by technology

[0006] The conventional method described in the aforementioned Patent Document 1 can be applied to the measurement of surface deviation or surface deflection, but it is difficult to perform high-precision measurement that can meet the level required in recent years.

In addition, this conventional method has the problem that it cannot be applied to the measurement of an aspheric lens that does not have a collar-shaped flat portion.

[0007] Such a problem also occurs in the measurement of surface deviation or surface deflection of other aspheric bodies such as an aspheric mirror having two mirror surfaces composed of a rotationally symmetric aspheric surface.

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