Lenses axial space ray tracing measurement.

In order to achieve the precise measurement of the lenses axial space, a new lenses axial space ray tracing measurement (ASRTM) is proposed based on the geometrical theory of optical image. For an assembled lenses with the given radius of curvature r(n) and refractive index nn of every lens, ASRTM uses the annular laser differential confocal chromatography focusing technique (ADCFT) to achieve the precise focusing at the vertex position P(n) of its inner-and-outer spherical surface Sn and obtain the coordinate z(n) corresponding to the axial movement position of ASRTM objective, and then, uses the ray tracing facet iterative algorithm to precisely determine the vertex position P(n) of every spherical surface by these coordinates z(n), refractive index n(n) and spherical radius r(n), and thereby obtaining the lenses inner axial space d(n). The preliminary experimental results indicate that ASRTM has a relative measurement error of less than 0.02%.