Current sets of LEP requirements, though different for specific industrial or medical applications, have some common features:
Multiple wavelength protection. Due to cost and operational limitations, LEP device should protect against several laser threats at the required optical density (OD).
High integrated luminance transmittance (ILT).
Blocking of several spectral bands naturally leads to the distortion of color perception. Unlike the ODs, there is no common set of requirements for color balancing (CB) of the LEP filters. Neutral gray is the self-evident goal, but it rarely could be achieved without sacrificing much of the ILT. There is also no established merit function, which precludes us from using standard mathematical programming techniques (GAMS et al.) for optimization.
GENTEX has developed an interactive VB program to facilitate hybrid approach, combining manual add-ons of color balancing dyes, calculation of the parameters (Purity vs. ILT etc) and visual evaluation of color perception. It also allows enhancing display readability by customizing the color palette for use with a specific LEP device. It is a user-friendly tool, providing fast evaluation of multiple LEP/CB/ILT combinations for reflection and absorption LEP designs