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 n_n 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 S_n 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%.