| 摘要 |
A sensor for sensing electromagnetic radiation from a viewing area is described. The sensor incorporates a housing having an aperture for receiving electromagnetic radiation from the viewing area and a sensing region located within the housing where the sensing region sensitive to electromagnetic radiation and operable to provide an electrical signal once a predetermined threshold condition is met. The sensor also includes a focusing element forming part of the sensor to direct electromagnetic radiation from the viewing area onto the sensing region, wherein the focusing characteristics of the focusing element may be modified to modify the viewing area of the sensor. 110 126 211 310 212 131 120' Figure 2a 301A110 126 310 212 131 120' Figure 2b |
