Abstract:
A photodetector control circuit in a photodetector for detecting light from a photodiode using a phototransistor and controls drive of the photodiode and detection of a current of the phototransistor has a received light amount detecting unit that detects a detection current, which flows through the phototransistor in accordance with a received light amount, by converting the detection current into a detection voltage, and compares the detection voltage with a reference voltage detected during reception of a reference light amount, to thereby detect a change in the received light amount, a diode current control unit for controlling a diode current that is caused to flow through the photodiode, and a control unit that detects a temperature based on a forward drop voltage of the photodiode and estimates a current change rate of the phototransistor based on the detected temperature.
Abstract:
PURPOSE: An apparatus for measuring afterglow of a fluorescent substance is provided to accurately measure afterglow time of the fluorescent substance under arbitrary condition. CONSTITUTION: An apparatus for measuring afterglow of a fluorescent substance includes a vacuum container(11) having a predetermined spacing part, a table(12) installed in the inside of the vacuum container and having a fluorescent sample solution mounting part in the upper plane, an exciting unit(20) installed in the upper part of the sample solution mounting part for generating ultraviolet rays to excite the fluorescent substance, a vacuum generating unit for making the vacuum container vacuous, an electric discharged gas injecting element for injecting electric discharged gas into the vacuum container, and a measuring unit for measuring the luminous state of the fluorescent substance excited by the exciting unit.
Abstract:
PROBLEM TO BE SOLVED: To provide a light beam detection circuit which is capable of accurately detecting a passage timing of a light beam and of reducing costs, and a light beam emission unit and an image forming apparatus which include the same.SOLUTION: A light beam detection circuit 3A includes: a detection signal generation unit which receives a light beam scanning a body 101A to be scanned, by one optical sensor 10 to generate a detection signal according to an amount of received light; a reference signal output unit 44 which outputs a reference signal proportional to a light amount control signal of a light emitting element LD1 emitting the light beam; and a synchronizing signal generation unit 35 which compares the detection signal generated by the detection signal generation unit with the reference signal outputted by the reference signal output unit 44 to generate a synchronizing signal for determining a position where scanning of the light beam on the body 101A to be scanned should be started.