| 摘要 |
<p>PURPOSE:To prolong the life of a control light emitting element and to attain a low power consumption by transmitting always a constant quantity of light to the control light emitting element for controlling a rotary drum mounting circuit and controlling the rotary drum mounting circuit accordingly. CONSTITUTION:LEDs 18a-18n constituting a recording control LED array or a reproducing control LED array are directly connected, and are driven by a common LED driving circuit 28. Light from one of these LEDs 18a-18n, for instance, the LED 18a is received and converted into an electric signal by a light emitting quantity monitoring photodetector 26, and the signal is transmitted, as light emitting quantity information, to a light emitting quantity control circuit 27. The LED driving circuit 28 is controlled so as to make a light emitting quantity of the LED 18a constant by the circuit 27 based on the light emitting quantity information. By the LED light emitting quantity control system, light emitting quantities of other LEDs 18b-18n are also controlled to be constant.</p> |
