| 摘要 |
PURPOSE:To improve measurement precision over the entire visual field region by uniforming and sufficiently reducing an error in digital quantization by adding correcting photodetecting elements which has the same size and are out of phase with a photodetecting element for the least significant digit of a digital code. CONSTITUTION:Correcting photodetecting element are arrayed having the same size and out of phase with a photodiode photodetecting element for the least significant digit among photodetecting elements arrayed in accordance with a prescribed digital code between an element on a start line and that on an end line. The slit width of slit light is equal to the length of the least-significant digit element, and the slit length is equal to the length between the center line of the start-line element and that of the end-line element. Then, waveforms are combined only where the output voltage of, for example, photodetecting elements 231 and 239 have excellent linearity, thus securing the entire measurement visual- field angle region. |
