无焦系统在“空间直线度”测量中的应用

The Application of Afocal System in Measurements of "Spatial Straightness"

在机械制造业中,常有一系列孔的中心组成的直线,称之为“空间直线”。多用内调焦式测微望远镜对其进行检测。但是对于远、近测试点不能有相同的成象质量和测量精度。本文试图解决这种“空间直线度”测量中对远、近测试点具有相近的测量精度和成象质量问题,即对远测试点和近测试点具有相同的倍率、孔径角,同时有相同的理论分辨率和象面照度,消除调焦误差,具有合格的成象质量。文中以一个无焦系统作为物镜,构成“等精度测量系统”,并研制成功仪器作为例子,说明无焦系统的应用。

'Spatial Straightness' is usually measured with an internal focusing alignment telescope. But it cannot ensure the same accuracy for both far and near test points. This paper intends to solve the problem of similar measuring accuracy and imaging quality for both test points. That is, to provide similar magnification, aperture angle, theoretical resolution and illumination in image plane, and to eliminate focusing errors and attain required imaging quality. In this paper an afocal system serves as the objective lens in the 'Equi-accurate test system'. For illustration, a prototype instrument is developed.