When evaluating PDLC film performance in its transparent state, haze and transparency are the two key specifications determining film clarity. Haze is a measurement of light diffused or scattered more than 2.5° from the specular direction when passing through a transparent material. Transparency is the percentage of incident light that is allowed to pass through the film. Gauzy automotive grade PDLC films have an on-axis haze of ~ 2.5% and transmittance of ~ 80% providing excellent clarity when in the transparent state.

On-axis haze is defined as the haze level when viewing the film at an angle of incidence of zero (normal to the surface) and off axis haze is the haze level when viewing the film at an angle of incidence > 0°. Due to the structure of PDLC, there is an inherent off-axis haze that is higher than the on-axis haze and can impact overall transmittance and therefore clarity. Having the lowest overall haze is critical to ensuring a good viewing experience.

When evaluating PDLC film performance in its translucent or “off” state, T-min and T-total are the key specifications that describe a film’s performance. T-min is the percent of incident light normal to the surface of the film when in the translucent state that is transmitted maintaining its angle of incidence ±2.5°. So, T-min is the percent of parallel light incident on the film that is passed through with minimal change in its angular orientation (see Figure 2-4). T-total is the total of all diffused, parallel, and scattered light that passes through a film in the translucent state (see Figure 2-5)

Figure 2-4 T-min is the Amount of Specular Transmission of Incident Light When in the Translucent State

Figure 2-5 T-total is Total Amount of Light (specular, diffused, and scattered) Transmitted When in the Translucent State

Gauzy’s PDLC films have a T-min of ~4% and a T-total of ~ 60%. When a low T-min and a high T-total are combined, the result is a high-quality image with a wide viewing angle and low visual disturbance of the surrounding environment as all elements behind the translucent glass are hidden. Table 2-1 summarizes the key transparent and translucent specs.