Method and device for measuring free-form surface based on reference plane comparative measurement

Abstract

The invention discloses a method and a device for measuring a free-form surface based on reference plane comparative measurement, and belongs to the technical field of optical precision detection. Themethod uses the high-precision plane flat crystal as a reference plane of an X-Y surface, utilizes the high-precision height measurement sensor and the free-form surface measurement sensor which arecoaxially installed to detect the high-precision plane flat crystal and the surface height information of the measured free-form surface respectively, utilizes the high-precision height measurement sensor to acquire the surface height information of the high-precision plane flat crystal to monitor and compensate the straightness error of an X-direction air-floatation guide rail and a Y-direction air-floatation guide rail, performs dimension reduction error separation on the surface appearance of the free-form surface, and realizes the nanometer precision detection of the appearance of the free-form surface. The method and the device for measuring the free-form surface based on reference plane comparative measurement can realize the detection of the free-form surface, provide high-precisionthree-dimensional linear positioning and scanning measurement, inhibit the influence of the straightness error of the movement of the X-direction guide rail and the Y-direction guide rail on the measurement of the free-form surface, reduce the influence of the Abbe error of the Z axis on the measurement, and realize the large-range and nanometer precision measurement of the free-form surface.

Description

technical field The invention belongs to the technical field of optical precision detection, and relates to a high-precision detection method and device for free-form surfaces, which can be used for nano-precision detection of free-form surfaces in precision optical systems. technical background The free-form surface element has the largest degree of freedom in surface morphology, and it is easy to eliminate aberrations in the imaging system. advantages such as sex. Using a free-form surface optical system to replace the previous optical system composed of a plane, a spherical mirror, and a coaxial quadratic mirror to improve imaging quality, reduce system volume and weight, and solve imaging accuracy, portability, and reliability issues has already been achieved. It has become an important trend in the development of optical systems. However, while the freeform surface increases the design freedom, it puts forward higher requirements for optical design, processing and in...

AI Technical Summary

Problems solved by technology

To sum up, the measurement accuracy of the existing measurement methods is greatly affected by the differences in the characteristics of the sample surface such as roughness, undulation, and inclination angle, which is the main technical bottleneck for improving the measurement accuracy of the free-form surface profile.

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