OSLO - Ray Trace

This section shows how to trace a single ray through a lens system.

Procedure

  1. Select File - Open and find the lens data file corresponding to the lens to be traced. In this example, we trace a ray through the doublet lens defined earlier.

  2. Select Calculate - Trace ray, which brings up the following dialog:

    For this example the object point is on the optic axis at infinity. Specify the ray height at the first reference surface (entrance pupil) in fractional coordinates. The reference height is 7.5 mm. If we want the ray to intersect at a height of 5 mm, we would enter 5.5/7.5 for FY, as shown.

    We have chosen to list direction cosines and to generate information for all surfaces.

  3. Click Ok when you have finished selecting parameters. The results appear in the text window. They may then be saved to a text file using the File - Save Text As menu choice.

Example Output

Example output is shown below: 

*TRACE RAY - LOCAL COORDINATES
 SRF        Y/L         X/K         Z/M      YANG/IANG   XANG/RANG      D/OPL
  1       5.000000      --        0.424190   -3.321783      --        0.424190
         -0.057944      --        0.998320    9.698502    6.376720    0.424190
  2       4.845716      --       -0.517631   -1.844329      --        2.662652
         -0.032184      --        0.999482   15.516482   14.039028    4.462902
  3       4.769901      --       -0.163170   -5.750525      --        2.355681
         -0.100197      --        0.994968    5.762786    9.668983    8.403244

  4       4.753469      --          --       -5.750525      --        0.163996
         -0.100197      --        0.994968    5.750525    5.750525    8.567239
 PUPIL      FY          FX                                              OPD
          0.666667      --                                         -404.465670

The standard output from the trace_ray command gives the (X, Y, Z) coordinates of the ray on each surface, the ray angles YANG and XANG (in degrees), and the distance D along the ray from the previous surface to the current surface. The full output shows, in addition, the direction cosines (K, L, M), the angles of incidence and refraction IANG and RANG (in degrees), and the optical path length from the entrance sphere up to the current surface.

Maintained by John Loomis, last updated 23 Sept 1998