Some of our clients have commented on a ‘milkiness’ they see in some Switchable Privacy Glass when viewed from certain angles in its ‘on’ state. This is referred to as the ‘haze factor’. In order to address this concern our Research Department recently carried out a series of comparative tests with four other leading PDLC films.
Each PDLC film was fitted with a busbar and laid up between 2 x 300mm pieces of our 6mm Saint-Gobain glass with a 1.52mm Solutia PVB film interlayer. The panels were labelled accordingly before being processed through our lamination plant. The results were interesting and affirming. When inspected with our light transparency meter, in their ‘on’ state, all of the competitors’ films proved to have less light transmission than ours, ranging from 68% to 71%. Switchglass’ showed a clear 73%.
Switchable Privacy Smart Glass in its ‘on’ state displays optimum clarity under normal lighting conditions. Factors such as reflected electrical illumination or natural light cast upon the glass do not favor its visible light transmission and should be taken into consideration when installing it. When viewed from acute or oblique angles, too, the ‘haze’ effect can appear to increase but is not considered a problem. Because of these concerns, Switchglass has completed further tests on its Switchable Privacy Glass: this time incorporating Low Iron Glass. Also known as Starfire Glass, Low Iron Glass has a reduced iron content which greatly increases light transmission.
The results were quite marked, with visible light transmission increased to 79%. In spite of the fact that it would add approximately 10% to the cost of the product, the conclusion is that this is clearly the way to go.
Switchglass applies rigorous methodology in its manufacturing process. Time, pressure, temperature – all these factors are minutely monitored in the lamination process. Also, as Switchable Privacy Glass is an electrical product, every single finished piece is checked at four points around the panel for constant conductivity.