| 摘要 |
PURPOSE:To make it possible to easily adjust a detecting area, by arranging a freely extensible infrared ray shield plate in front of a reflective mirror. CONSTITUTION:A pair of infrared ray shield plates 8, 8' each of which has a freely extensible bellow like shape are arranged in front of a reflection mirror 2 gathering infrared rays B emitted from the human body 1 to a piezoelectric sensor 3 and extended and contracted along guide grooves 10, 10' to change the size of an opening 9 to make it possible to vary a detecting area E enabling the incidence of infrared rays emitted from the human body 1 to the reflection mirror 2. Only by extending and contracting the infrared ray shield plates 8, 8' to the direction shown by an arrow A, the detecting area E can be easily regulated. In addition, because the infrared ray shield plates 8, 8' may be only formed into the bellow like shape, the titled apparatus becomes inexpensive. |
