| 摘要 |
A shutter for a light source is described, the shutter being switchable between a substantially opaque condition and a substantially transparent condition. In one embodiment the shutter comprises a layer (26) of a liquid crystal material located between polarised elements (22, 24), a control system (30) being provided to control the orientation of the crystals of the of the layer (26). A shuttered light source incorporating the shutter is also described. |
