Liquid-crystal sunglasses indicating overexposure to UV-radiation

摘要

Liquid crystal sunglasses indicating overexposure to UV-radiation comprising a pair of liquid-crystal lenses (12 and 14) a rim (10), a bridge portion (14) which support the lenses, and a pair of temples (18 and 20) which supported by the rim. The rim (10) supports a pair of solar cells (28 and 30) and a dual-photodetector sensor (26) which can separately measure an incident UV-A radiation and a UV-B radiation and convert these radiations into electric signals. The sunglasses's rim also incorporates a microcontroller (36). The lenses have a laminated structure composed of a color mask (43), an input polarizing plate (44), a liquid crystal cell (50) sandwiched between a pair of voltage-controlled active matrices, and an output polarizing plate (46). Each active matrix consists of a plurality of sets of pixels which control the transmission of light through the respective color cells of a mosaic mask. The microcontroller also incorporates a frequency generator (104) and a memory unit. The memory stores an algorithm for calculating thresholds of UV radiation. When these thresholds are exceeded the lenses give to the wearer a warning signal either changing the color of the lenses or causing blinking.