| 摘要 |
PURPOSE:To execute the optical measurement with high accuracy by controlling optimally a light emission time of a light emitting element of a prescribed output. CONSTITUTION:Each timing of a pickup optical system 3 is synchronized by a timing control part 7. That is, the timing of a turn-on time Tl and a turn-off time Td of a semiconductor laser 1 and the timing of an accumulation time Tc and a transfer time Tt of a line sensor 4 are executed simultaneously by the timing shown in the figure, respectively. In this turn-on time Tl, the side of the transfer time Tt and the side of the accumulation time Tc are set as a pre-light emission time Tp and an effective light emission time Te, respective ly. Also, the pre-light emission time Tp is determined so that the pre-light emission time becomes a longer time that the time when a temperature of a laser chip becomes stable after turn-on is started. Moreover, the effective light emission time Te can be varied between 0<Te<Tc, and the light quantity can be controlled effectively against a sensor 4. That is, the effective light emission time Te is controlled by a control part 7, by which the effective light quantity of a luminous flux which is made incident on the sensor 4 is set to an optimal value. |
