| 摘要 |
<p>PURPOSE: To provide an infrared sensor, which can exhibit the proper detecting function all the time in a broad detecting area. CONSTITUTION: This sensor comprises a cover 12 which has a visible-light cutting function, an optical unit 13 which condenses the light that is cast through the cover 12 at the specified position, and a pyroelectric element which receives the light condensed by the optical unit 13, and forms the detected signal. The thickness of the cove 12 is changed in accordance with the distance of a detecting area in the direction of an optical axis. The optical unit 13 is movably constituted with respect to the cover 12 so that the distance of the detecting area in the direction of the optical axis is changed. The thickness of the cover 12 changes in accordance with the movement of the optical unit 13. The proper sensitivity is obtained with respect to the broad detecting area by setting the thickness of the cover 12 based on the relation to the distance of the detecting area affecting the sensitivity of the sensor.</p> |
