| 摘要 |
PURPOSE:To increase the emission power of a laser source and to stably read information by shifting off the optical axis of the laser source from the center of an aperture. CONSTITUTION:The optical axis of the laser diode 1 is shifted off the center of the aperture i.e. the diode 1 is inclined clockwise. When the laser diode 1 is thus inclined, the proportion of the quantity of the light that passes through the aperture 8 to the whole quantity of emitted light from the diode 1 is reduced. Accordingly, if the quantity of the incident light on a photodetector 7, that is, the output signal level of the detector 7 is constant, the emission quantity of the laser diode 1 can be increased. Thus the emission power of the diode 1 can be enhanced, and information can be read accurately. |
