LENS DESIGN FOR THE NEAR IR ... CORRECTION OF PRIMARY CHROMATIC ABERRATION

The dispersion characteristic of conventional optical glass types will vary as a function of the wavelength region being considered. In the 1.0 to 1.5 mu m region, the dispersion of traditional crown and flint glass types is found to be nearly the same. This results in a unique c ondition when attempting a lens design solution for this spectral regi on. A typical example is described here that will be helpful in unders tanding this phenomenon.