| 摘要 |
PURPOSE:To prevent saturation at a high brightness contrast and to detect an object with a brightness contrast over a wide range by adding a simple circuit to a hill-climbing system focus detection circuit. CONSTITUTION:A resistor 3 (4) is inserted between a transistor(TR) 10 (11) of a current mirror circuit 1 and a power supply Vcc. Moreover, a variable resistor 6 to adjust the degree of a compression rate is inserted between a constant current circuit section of a detection circuit 7 and the power supply Vcc. Through the constitution above, since the compression rate of an integration current is increased for an object with a higher brightness contrast, no saturation takes place. |
