| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect the presence or absence and the position of even a still human body over a wide range by detecting the presence or absence of a human body from the output signal of a signal-processing circuit for filtering and amplifying a signal from an infrared sensor. SOLUTION: A multiple Fresnel lens 2 consists of a double Fresnel lenses, and an outer Fresnel lens focuses infrared rays on each lens surface of the inner Fresnel lens. Further, the inner Fresnel lens focuses infrared rays to a charging type infrared sensor 3. A signal-processing means 4 consists of an LPF circuit for eliminating a power supply noise, an amplification circuit for amplifying the small signal of the charging type infrared sensor 3, and an ADC for converting the amplified signal to a digital signal. The signal-processing means 4 inputs infrared rays that are discharged from the human body to a microcomputer as a digital signal whose noise is reduced. A human body detection means 5 detects a human body from a time-series digital signal sent from the charging type infrared sensor that passes through the signal-processing means 4.</p> |
