March 2000 © TOSHIBA TEC 5-15 DP120F/DP125F Mechanical DescriptionWhen a forward voltage is applied to this semiconductor laser, the holes and electronscombine at the junction area as in the case of the diode, and the energy discharged uponthe joining of the holes and electrons is discharged as light. The discharged light is en-closed in the junction area, and is reflected by the reflecting surfaces of both sides, beingreflected reciprocally within the junction area.Due to the consecutive joining holes and electrons as a result of the reciprocal move-ment, the light is correspondingly amplified. Then, when the light has become sufficientlyamplified, the semiconductor laser emits a laser beam through the reflecting surfaces.This is an invisible laser radiation, but it is a good monochromatic light beam with highluminance at a large-volume output. Consequently, the laser beam can be condensed bya lens to an extremely small focal point with high luminance, thereby permitting its use ina laser facsimile.(2) Laser driveThe Main PBA controls the laser beam drive signal (VIDATA) by the print data.The laser beam drive signal is sent to the laser driver in the LSU to control the currentflowing to the laser diode.The laser diode generates a laser beam when a current that equals or is greater than thestipulated value (I th) flows.Amount of laser lightI thLaser driving currentFig. 5-3-905-03-09
