| 摘要 |
<p>PURPOSE:To eliminate malfunction due to external turbulence and provide possibility of sensing of a stationary object by using polarized infrared rays to a source for infrared rays to be projected, and sensing the difference between reflected polarized infrared rays and a natural infrared beam when any object exists. CONSTITUTION:Infrared ray polarizing pieces 3, 5 and other ones 9, 7 transmit polarized infrared rays in respective identical polarization planes, while the polarizing pieces 3, 9 and the ones 5, 7 transmit polarized infrared rays whose polarization planes are different in 90 deg. Infrared projecting elements 2, 8 make light emission alternately with an oscillator 11 and inverter 12, and polarized infrared rays which the polarizing pieces 3, 9 have transmitted are reflected by an object to be sensed 1, and the resultant beam is sensed by either of the infrared sensing elements 4, 6 solely which thereupon give output signals alternately. If there is no object and a natural infrared beam is incident, sensing takes place with both elements 4. 6, which however are in such a connection that their outputs set off one another and do not emit any output signals. The reflected beam from the object 1, on the other hand, is emitted as a signal having an amplitude twice as large as the output of each element 4, 6. The output signal therefrom is wave detected 17 to form a signal corresponding to the object 1. Accordingly there is no malfunction due to external turbulence any more.</p> |
