An optical glass plane angle measuring system with photoelectric autocollimator

Optical glass is the most widely used optical material.It is necessary to measure its geometric characteristic quickly and reliably to meet the quality of optical glass.A vision measuring system combining photoelectric autocollimation system with high-precision rotary stage is designed to measure the parallelismand angle of optical glass plane.A novel method is proposed to overcome the difficulty ofmeasuring parallelismof optical glass.The model of parallelism and angle measurement is established and the feasibility is analyzed.The image processing algorithm combining Steger algorithm with the least square method is selected.The uncertainty of angle measurement system for angle measurement is 3.0″.The system can solve the problem of measuring the angle of optical glass with high precision and has important significance for optical system.

Design of the Rotation Angle Measurement System for the Atmospheric Dispersion Corrector (ADC)

In order to measure the rotation angle error of the worm and gear mechanisms in the atmospheric dispersion corrector( ADC),a novel measurement system based on the autocollimator is designed in this paper.Based on the position relations between the shaft and spot converged by rays of autocollimator,the rotation angle can be calculated quickly and conveniently using a brief algorithm. An optical wedge is introduced to the measurement system for suppressing the awful measuring error caused by the axial wobbly error. The measurement system can measure the shaft rotation angle at any rotation position,which is the novel usage of the two-dimensional autocollimator. Its optical layout is very simple. Only an optical wedge and two plane mirrors are needed besides the autocollimator. The measurement accuracy of the proposed method is less than±0.5 arcmin. In the measurement of two worms and gears mechanisms in ADC,the rotation angle error are±0.05° and ±0.07° respectively,which all satisfies the design demand( ±0.1°). The proposed measurement system can be also suits for some engineering fields.

TEST METHOD FOR SINGLE INTERIOR RIGHT ANGLE IN A CORNER CUBE PRISM

A new test method for single interior right angle in a corner cube prism is presented. Some key points and parameters are analyzed and derived. The advantage of this method is concluded by comparing with some current conventional methods.

Feasible Resolution of Angular Displacement Measurement by an Optical Angle Sensor Based on Laser Autocollimation

The feasible resolution of angular displacement measurement by an optical angle sensor based on laser autocollimation is investigated.Improving the sensor sensitivity while maintaining the noise level of the sensor signal as low as possible is necessary to achieve high-resolution angular displacement measurement.In this paper,the contribution of each component,such as a photodiode,a trans-impedance amplifer,and an analog-to-digital converter in the optical angle sensor,to the noise level of the sensor signal is frst estimated on the basis of theoretical equations.The feasible sensitivity of the optical angle sensor is also estimated in numerical calculations.The sensitivity of a photodiode element at the edge of its photosensitive area is evaluated in experiments to realize the estimation of the angle sensor sensitivity.Experimental results are applied to the numerical calculations.The infuences of the measurement laser beam diameter,the spot diameter of the focused laser beam on the photosensitive area,and the focal length of the collimator objective of the optical angle sensor are also consid-ered in the numerical calculations.Finally,a prototype optical setup is developed.Experiments are performed to demonstrate that a compact optical angle sensor based on laser autocollimation with a collimator objective having a focal length shorter than 100 mm can achieve a resolution beyond 0.001 arc-second with a bandwidth of 1 kHz.This resolution is better than those achieved by commercial autocollimators employing an image sensor or a position-sensitive detector.The industrial contribution of this paper lies in the detailed breakdown of noise components in the readout signal of an angle sensor in a practical condition and the systematic estimation of its feasible resolution as well as its sensitivity.