| 摘要 |
PURPOSE:To vary an angle of optical deflection over a wide range by fitting a piezoelectric transducer to one elastic material, and joining two kinds of elastic material which differ in the phase speed of an acoustic elastic wave in a plane which does not cross the propagation direction of the elastic wave at right angles. CONSTITUTION:The elastic materials 2a and 2b which differ in the phase speed of the acoustic elastic wave are joined together in a boundary surface 6 which is not parallel to the end surface to which the piezoelectric transducer 1 is fitted. When the acoustic elastic wave 3a excited by the transducer 1 reaches the boundary surface 6, it is diffracted because of the difference in phase speed between the materials 2a and 2b to obtain an acoustic elastic wave 3b which differs in propagation direction and wavelength. When the phase speed of the material 2a is larger than that of 2b, the wavelength of the elastic wave 3b is shorter than that of 3a and circuit diffraction intervals are small, so the angle of light diffraction is made large at a relatively low frequency. |
