| 摘要 |
<p>1,104,856. Piezoelectric elements. CARL ZEISS JENA VEB. 20 May, 1965, No. 21349/65. Heading H1E. [Also in Division G2] A tubular body of electrostrictive material is provided with inner and outer electrodes, either or both of these electrodes being of non- uniform extent in the axial direction whereby the tube may be expanded non-uniformly upon application of a voltage. The ends of the tube may be used to support the transverse semitransparent mirrors of a Fabry-Perot interferometer and the tube used to adjust the distance between the mirrors and their relative angular disposition. A typical distribution of one of the electrodes (either inner or outer) is depicted in the Figure which shows the developed cylindrical surface. The opposite surface (outer or inner) carries a uniform electrode layer. The non-uniform electrode in this instance has three portions, the portion 40 being of uniform extent in the axial direction and serving for uniform expansion and contraction of the tube. The other two layers 41, 42 have sinusoidal distributions mutually displaced circumferentially by 90 degrees, the adjacent sinusoids 36, 37 and 38, 39 being insulated from one another. Thus, opposite voltages applied to areas 36, 37 will cause the mirrors to tilt about an axis parallel to a radius of angle 90 degrees. Voltages applied to areas 38, 39 cause tilt about an axis at right angles to this. The Specification describes several other forms of electrode distribution suitable for providing tilt about a selected axis, e.g. about one of three axes distributed at 120 degree intervals (Fig. 8, not shown). The displacement of the axis of tilt from the centre of the cylinder depends upon the relative magnitudes of the expansions and contractions. These may be regulated by the areas of the sinusoids which do not necessarily have the equal maxima shown in the Figure. Further, the staggering between the sinusoidal portions may be such as to allow overlap (e.g. as in Fig. 12, not shown). In a modification, the non-uniform electrode layers are superimposed and insulated from each other by interposed dielectric layers. The electrostrictive material may be a ceramic.</p> |
