Photometric simulation and uniformity optimization of a novel Ganzfeld-design

Abstract

A stimulator is essential to generate electroretinographic (ERG) signals, and the widely used stimulator is the Ganzfeld which is supposed to provide uniform luminance full-field visual stimuli. Our purpose was to design an improved Ganzfeld to be used for both human and animal research and study the effect of geometrical parameters on the luminance uniformity. The designed model was simulated with the optical software ASAP, and the Monte Carlo method was used for raytracing. An experiment design method, which is two-level Fractional Interaction Design (2FI) method, was applied to reduce the computation time and to study the main effects and interaction effects of designed geometric parameters on illuminance and luminance uniformity in the Ganzfeld and to optimize the parameters. We found that not all geometric parameters of the illumination affect the uniformity of the Ganzfeld the same way. The angle of the tube containing the light source and its length have significant effect on both illuminance and luminance uniformity. In contrast, its height and width do not affect uniformity significantly while the interactions of the Ganzfeld sphere and the attached illumination tube do. As a result of the simulations, an optimized new Ganzfeld design with the improved illuminance and luminance uniformity of 94.9% and 83.3%, respectively, was achieved.