Electrochromic devices for transmissive and reflective light control

Abstract Fundamental properties of a transmissive electrochromic device are described. The device consists of a semisolid electrolyte and a WO3 film sandwiched by a pair of transparent conductive glass sheets. The transmittance of the device can be arbitrarily controlled within the range from 80% to 10%. The response time was found to be greatly dependent on the device size. The lifetime for repetitive operations is more than 105 cycles. Reasonably good durability has been determined. This device is capable of controlling the reflectance of a mirror, with the reflective layer coated on the either surface of the outer glass sheet. Details of this reflective device are also described. The reflectance of the mirror of the size of 25 cm × 6.5 cm can be changed from 72% to 20% within 4 s at 1.5 VDC. This device is suitable as an antidazzling mirror for motor cars.