| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a thermal protection mechanism of an electronic endoscope having a simple mechanism. <P>SOLUTION: The thermal protection mechanism of the electronic endoscope is provided on the end surface 12a of the distal end portion 12 of an insertion portion of the electronic endoscope and is equipped with a water feed nozzle 14, a light irradiation port 15, and a metal connecting member 17 as metal members for detecting a temperature of the distal end portion 12, an LED light source provided on the distal end portion 12, a constant voltage source which applies a certain voltage to the LED light source and makes the LED light source emit light, and a PTC thermistor 31 which is connected to the constant voltage source and has an ohmic value changing in accordance with the temperature detected by the water feed nozzle 14, the light irradiation port 15, and the metal connecting member 17. The PTC thermistor 31 detects the temperature of the distal end portion 12, and the ohmic value changes in accordance with the detected temperature. When the ohmic value of the PTC thermistor 31 suddenly increases because of abnormal heating, a current flowing to the LED light source is reduced. Consequently, the abnormal heating of the distal end portion 12 is prevented by the reduction in the light amount of the LED light source and the reduction in the amount of heat generation. <P>COPYRIGHT: (C)2012,JPO&INPIT |
