| 摘要 |
PCT No. PCT/GB94/00931 Sec. 371 Date Nov. 13, 1995 Sec. 102(e) Date Nov. 13, 1995 PCT Filed Apr. 29, 1994 PCT Pub. No. WO94/25895 PCT Pub. Date Nov. 10, 1994An electrically-controllable liquid crystal filter device comprises two partially-reflecting substrate structures mounted substantially parallel to each other with a space therebetween to form a Fabry-Perot filter. A layer of ferroelectric liquid crystal material is disposed in the space, the liquid crystal material being switchable, by application of an electric field, between different refractive index values whereby the device is switchable between transmissive and reflective states for light of a particular narrow wavelength band. The spacing of the substrate structures is selected in relation to the wavelength of light to be transmitted, such that the Fabry-Perot filter operates in a low order state, which may be the first order.
|
