| 摘要 |
<p>PURPOSE:To rapidly alarm illegal invasion to a vehicle caused by breaking window glass by emitting an ultrasonic wave toward the window glass, and receiving a reflected wave. CONSTITUTION:An ultrasonic wave unit 2 is attached to the room side of the roof 1 of the vehicle. The ultrasonic wave emitted from the wave transmission part of the ultrasonic wave unit 2 is reflected on window glass 4, front glass 5, and window glass 6, and is received at the wave reception part of the ultrasonic wave unit 2. When the window glass 4 and 6 or the front glass 5 are broken and the state change of the ultrasonic wave is detected at the wave reception part, an alarm is issued.</p> |
