| 摘要 |
PURPOSE:To make the performance of an image converting element high by using an interdigital electrode for an extracting electrode of the image converting element so as to decrease a DC resistance of a photoconductive thin film and decrease the propagation loss of a surface acoustic wave. CONSTITUTION:The interdigital electrodes 11, 12 are formed on the surface of a piezoelectric base plate 13 being a surface acoustic wave propagating medium and the photoconductive thin film 14 is formed to the surface acoustic wave propagating part on the base plate 13. The interdigital extracting electrodes 21, 22 are formed to the thin film 14 and the direction pointed out by the extracting electrodes 21, 22 is made in parallel with the direction of surface acoustic wave propagation. Further, the length of the electrode gap of the interdigital extracting electrodes 21, 22 is made shorter than the effective wavelength in use. Then, the DC resistance of the thin film 14 is decreased and the propagation loss of the surface acoustic wave is reduced, the S/N of an optical ray is improved and also the performance of the image converting element is made high. |
