| 摘要 |
<p>PURPOSE:To reduce a source voltage by using the same compsn. to form the insulating layer provided on one side face of a single crystal plate having an electrooptic effect and optical transmission effect and the insulating layer of an optical image element provided with transparent electrodes for applying an electric field to said insulating layer and the single crystal plate. CONSTITUTION:Bi12SiO20 or Bi12GeO20 added with an impurity is used as the insulating layers 2, 2'. Any of Ga, Al, or In or Ga and Ca, Al and Ca or In and Ca is used as the impurity to be added. The specified voltage distribution determined by the thicknesses of the single crystal plate 1 and the insulating layers 2, 2' and the dielectric constans thereof is generated in an optical image element if a voltage V is impressed by a power supply 4 connected to the transparent electrodes 3, 3' to the single crystal plate 1 and the insulating layers 2, 2', but since the insulating layers 2, 2' consisting of inorg. insulating materials are large in the dielectric constant, the source voltage can be set low. The voltage to be impressed to the single crystal plate 1 is, therefore, increased in the case of using the element with the same source voltage value. The control ratio of the output of the optical image element is improved.</p> |
