| 摘要 |
<p>PURPOSE:To prevent the generation of an erroneous work by providing sewn material detecting sensors composed of CdS of the same property and a luminous intensity detecting sensor of the external light separately, and comparing the output of a device to add a bias voltage to the output of the sensor B, and the output of the sensor A. CONSTITUTION:The second sensor 2 to detect the luminous intensity of the external light having the same property with the first sewn material detecting sensor 1 is disposed near the first sensor 1 not to be covered by the sewn material. A specific bias voltage is added to the output of the sensor 2 by a light- electricity converting and bias circuit 5. Furthermore, in a comparison circuit 6, the output of the sensor 1 and the output of the circuit 5 are compared to detect the presence of a sewn material. As a result, no erroneous operation is generated even though there is a power failure, a bulb cutting of a bias light source, a cutting of the sensor, a removal of a connector or the like. Moreover, the regulation of the sensitivity of device responding to the variation of the luminous intensity, the quality, the color of the cloth and the like becomes unnecessary.</p> |
