Development and characterization of a liquid-crystal projection unit for adaptive structured illumination

We did a comprehensive characterization of liquid crystal displays. The aim was to select the most proper for the development of an adaptive light pattern projector for use in industrial profilometry. Super twisted nematic displays have been chosen for this application. Active matrix displays have proven to be superior to passive matrix displays in terms of contrast, spatial characteristics of transmission, transient behavior of the transmission, and dependence of the transmission curves upon temperature. The choice of a suitable liquid crystal display made it possible to define the project criteria for the development of the projector unit. The main features of this projector and its use with profilometry for automatic quality control in industrial framework are presented.