| 摘要 |
<p>PURPOSE:To obtain an optical detector capable of surely removing disturbance light and reacting only to the light intensity of light emitted from a light emitting element by driving the light emitting element by high frequency AC and removing a DC component on the light receiving element side. CONSTITUTION:An output from a current/voltage conversion part is a signal (d) and a signal waveform obtained by superposing the real output signal of an LED to the disturbance light level (t) of a DC component is formed, and when the output signal (d) is passed through the filter means 1, only the high frequency component shown in a signal (e) can be obtained. When the high frequency component is applied to a smoothing means 3, an output signal (f) depending upon only the light intensity of light emitted from the LED which is obtained by removing the DC component of the disturbance light can be obtained. The output signal (f) is converted into a digital signal by an A/D conversion part 6 and the digital signal is applied to an MPU. Thus, noise due to disturbance light is cut off by the DC component removal of a receiving signal. Consequently, an optical detector completely prevented from the reception of noise due to disturbance light can be obtained.</p> |
