An experimental study of light modulator using magnetic fluid

초록

A type of light modulator using light-absorbing magnetic fluid has been studied experimentally. The basic operation principle and design of the modulator are addressed. It is shown that the luminance of the device can be modulated by applying a moderate level of electric current to a light-reflecting metal electrode. A high contrast ratio comparable to that of printed material was obtained using a kerosene-base magnetite magnetic fluid with a saturation magnetization of 196 G and a thickness of around 20 mu m. Doubling of the luminance from a minimum level takes about 200 ms for a driving current of 80 mA. The operation speed of the cell was found to increase almost exponentially with driving current, suggesting the possibility of motion picture applications. (C) 1999 American Institute of Physics. [S0021-8979(99)43408-5].