Detector and lock controller using same
First Claim
1. A detector for detecting a target object approaching and retreating, said detector comprising:
- an oscillator device for generating a transmission wave;
a branching device for branching said transmission wave generated by said oscillator device;
a transmission device for transmitting said transmission wave into space as electromagnetic waves;
a reception device for receiving the transmission wave transmitted by said transmission device and reflected by said target object;
a mixer for mixing a reception signal received by said reception device and a branched signal branched by said branching device to output a mixed signal;
a judging device for switching on a detection output indicating said object approaching and retreating based on an increase and a decrease of said mixed signal outputted from said mixer;
wherein a detection distance is set within ¼
wavelength of frequency effective for the detection.
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Abstract
A lock controller has main apparatus provided to a lockable door and a detector for detecting an approaching or retreating target object. The detector includes an oscillator device for generating a transmission wave, a branching device for branching the transmission wave, a transmission device for transmitting the transmission wave into space as electromagnetic waves, a reception device for receiving the transmission wave reflected by the target object, a mixer for mixing a reception signal received by the reception device and a branched signal branched by the branching device to output a mixed signal, and a judging device for switching on a detection output indicating the target object approaching and retreating based on an increase and a decrease of the mixed signal outputted from the mixer. A detection distance is set within ¼ wavelength of frequency effective for the detection. The main apparatus sends by wireless transmission a specified request signal to a portable device carried by the user, and if an answer signal is received from the portable device in response, causes the lockable part to be unlocked after ascertaining that the received answer signal is a correct signal.
18 Citations
3 Claims
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1. A detector for detecting a target object approaching and retreating, said detector comprising:
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an oscillator device for generating a transmission wave;
a branching device for branching said transmission wave generated by said oscillator device;
a transmission device for transmitting said transmission wave into space as electromagnetic waves;
a reception device for receiving the transmission wave transmitted by said transmission device and reflected by said target object;
a mixer for mixing a reception signal received by said reception device and a branched signal branched by said branching device to output a mixed signal;
a judging device for switching on a detection output indicating said object approaching and retreating based on an increase and a decrease of said mixed signal outputted from said mixer;
wherein a detection distance is set within ¼
wavelength of frequency effective for the detection. - View Dependent Claims (2)
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3. A lock controller comprising a detector according to claim 3 and a main apparatus which is provided to a structure with a lockable part having a handle and being adapted to open and close, wherein said main apparatus is adapted to send by wireless transmission a specified request signal to a portable device carried by said user, to receive an answer signal from said portable device in response to said request signal, and to cause said lockable part, if locked, to be unlocked after ascertaining that said received answer signal is a correct signal.
Specification