| 摘要 |
PURPOSE:To simplify an adjustment process and to improve picture quality by controlling a pulse width and a driving current by a detection light quantity. CONSTITUTION:A frequency/voltage conversion part(FVC) 103 outputs analog signals corresponding to the frequency of a CLK and an analog voltage FVC is compared with a reference voltage in a comparator inside a modulation switching part 102. Output from the FVC 103 or a fixed level is selected by externally set MODSEL. Since SSEL for which either PWM or luminance modulation is decided depending on the high and low of the fixed level is outputted, pin input can be performed as well so as to set the fixed level is an outside. A detection current IPD from a light quantity detection means 1052 is current/ voltage converted in an APC 104, subjected to sample-and-hold by signals SAM PLE from the outside and inputted to a signal modulation part 101 as the analog signals APCDATA or directly superimposed on phiA and a light beam driving current is corrected. Thus, the adjustment process is simplified and the picture quality is improved by an optimum modulation system. |
