| 摘要 |
PURPOSE:To eliminate the need for a feeder cable to a needle by shielding light to an image sensor array from a light source by a sensor yoke mounted on the needle side. CONSTITUTION:A light-shielding detecting section composed of an LED 12, a condenser lens 13 and the chip 11 of an image sensor is installed on the stator side, a sensor yoke 7 set up to a needle is passed between the LED 12 and the condenser lens 13, and light to the chip 11 of the image sensor is shielded in response to the position of the needle. A light-shielded section is detected by an output from the image sensor, thus determining the location of the needle. There is only the sensor yoke 7 on the needle side, thus eliminating the need for a wiring. |
