| 摘要 |
PURPOSE:To securely detect a fire without any malfunction by detecting the wavelength of light in the infrared-ray range which is transmitted through a liquid crystal display element. CONSTITUTION:The liquid crystal display element 1 for fire detection is provided with a polarizing plate 4 which has spectral characteristics only in the infrared- ray range outside an upper substrate 2 and a lower substrate 3, and a switch 5 is turned on to apply a constant voltage between the upper substrate 2 and lower substrate 3. Further, a sensor 6 is arranged on the back surface side of the element 1. For the purpose, the switch 5 is turned on to apply the voltage to the element 1, which is used in this state. If a fire takes place, the wavelength of light in the infrared-ray range which is emitted by the flames is transmitted through the elements 1, so the sensor 6 detects the occurrence of the fire. Thus, the element 1 transmits only the light with the wavelength in the infrared-ray range, so it does not senses normal light and also securely detects the fiber without malfunctioning. |
