| 摘要 |
PURPOSE:To realize highly precise follow-up ability by generating a previously set reference voltage by an input signal containing an external factor, and generating automatically a variation corresponding to this factor. CONSTITUTION:A reference voltage generation circuit used for exposure position correction in an exposing process, i.e., one of the manufacturing process of an optical disk, is constituted of an operational amplification circuit consisting of operational amplifiers OP2-OP3, a variable resistor VR3 and resistors R8-R15. At that time, the resistance values between both ends of the resistors R8-R15 and the variable resistor VR3 are set at the equal value, and the resistance values of the resistors R12-R15 are set at the different equal value. Besides, the input signal Vin passes through the OP2, and generates signal voltages VA, VB through the resistors R8-R11 and the variable resistor VR3, and comes to be the reference voltage Vref by the differential amplifier OP3. Thus, even if the input voltage Vin varies, the correction following this variation is performed automatically, because the reference voltage Vref is determined unconditionally by the input voltage Vin. |
