| 摘要 |
PROBLEM TO BE SOLVED: To provide a lens meter of a simple constitution in which current value of a current passing through a green LED does not greatly vary even if an operating voltage of the green LED varies. SOLUTION: The lens meter comprises the green LED 13 for irradiating a test lens L with measuring luminous flux; a power supply circuit SC for supplying electric power for the green LED 13; a light receiving element (CCD11) for receiving the measuring luminous flux transmitted through the test lens L; and an arithmetic and control circuit 24 for computing refraction characteristics of the test lens L on the basis of output of the light receiving element (CCD11). The electric power has a first voltage value set greater than the operating voltage of the green LED 13. The power supply circuit SC has a resistor R for setting the first voltage value at a second voltage value, the operating voltage of the green LED 13. COPYRIGHT: (C)2006,JPO&NCIPI
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