Switchable Glazing and Smart Glass
Switchable glazing is automotive glass whose optical state can be changed electrically; smart glass and dimmable glass are common umbrella terms.
Main forms
- Suspended-particle device (SPD) film changes tint when voltage controls the alignment of particles within the glazing. It normally preserves a view while varying transmitted light, but the available range and unpowered state are product-specific. AGC Automotive: Smart Glazing Digital Curtain
- Polymer-dispersed liquid crystal (PDLC) material changes how light is scattered. It commonly switches between clearer and frosted or milky states, so it behaves more like a translucent curtain than a dark tint. AGC Automotive: Smart Glazing Digital Curtain
- Electrochromic glazing changes optical properties under an electric field or current flow. Its switching speed, color, power requirements, and darkest state differ from SPD and PDLC implementations. Continental: Switchable automotive-glass technologies
How the terms differ
Switchable describes a function, not one construction or performance standard. Product terms such as opaque, privacy, dimmed, and clear are not interchangeable: a frosted state can still admit diffuse light, while a tinted state can preserve a view. Solar heat control also depends on coatings and the complete glazing stack, so a darker appearance does not by itself establish lower cabin heat. AGC Automotive: Smart Glazing Digital Curtain
For the wider vehicle-window context, see Vehicle Windows: Safety, Solar Control, Noise, Wipers, and Smart Glass. Roof layouts, heat control, shading, and ownership trade-offs are covered in Glass Roofs: Design, Heat Control, Safety, and Smart Glass.