In normal conditions, the Critical Flicker Frequency is usually 60Hz. But in some special conditions, such as low spatial frequency and high contrast between frames, these special conditions have high probability to occur in some TPVMbased applications. So it’s extremely important to verify if a visual signal with a combination of temporal and spatial frequency can be recognize by human eyes. Based on the research in the last paper ’ ’Window of Visibility’ inspired security lighting system’, this paper introduces the measuring method of WoV of human eyes. In this paper we will measure critical flicker frequency in low spatial frequency and high contrast conditions, and we can witness a different conclusion from the normal conditions.

This study investigated the relationship between the parameters of the DLP manufacturing process and the structure of photopolymerizable acrylic resins. Four different process parameters were established to produce different thin-walled acrylic sample series: exposure time, layer thickness, area offset, and number of transition layers. The structure and the surface of the obtained samples were examined with the use of the FTIR–ATR method and an optical microscope, respectively. It was proved that extension of the exposure time increases the density of crosslinking and sample thickness. A decreasing crosslinking density due to rising layer thickness is observed. The area offset affects only the dimensions of the sample, predictably reducing the dimensions of the sample as the compensation increases. The absence of transition layers proved unfavorable in many respects, both structurally and geometrically.