GB912863A - New or improved means for animating optically projected images - Google Patents

Abstract

912,863. Polarizing image-animating devices. TECHNICAL ANIMATIONS Inc. April 13, 1960 [July 28, 1959], No. 13241/60. Class 97 (1). For giving an impression of movement in part of a projected image (or a directly viewed transparency) a laminated assembly comprising a polarizing lamina and a lamina made up of bi-refractive elements, the two laminµ being stuck together, is applied to the corresponding part of the image-bearing transparency. The image-carrying beam is then directed through a rotating polarizer. As shown in section in Fig. 3 the assembly comprises transparent supporting sheets 8, 10, between which is a polarizer 9, a layer 7 containing the bi-refringent elements and a protective backing layer 12 for an adhesive layer 11. The layers are held together by transparent adhesive layers 13. A second polarizing element is rotatably mounted in the projecting apparatus. As shown in Fig. 4 the bi-refringent elements are in the form of strips, preferably of a molecularly-oriented resin, the molecules in each strip having their optic axes parallel and at a small angle to those in an adjacent strip as indicated by the hatched lines. An interference colour produced by phase retardation in the first strip in conjunction with a particular angular setting of the polarizing axis of the rotatable polarizer will be duplicated at successive strips on rotation of the polarizer as this angular relationship between the polarizer axis and the optic axis of each successive strip becomes satisfied. The interference colour will thus appear to move across the strips. Adjacent sector-shaped strips may be arranged to form a circle whereby an apparent rotary motion is produced in the projected image. Concentric annular strips produce radial movement. A random arrangement of small elements will produce a " sparkling " effect. If a diagonal half of a rectangular array of linear strips as in Fig. 4 is covered with a quarter-wave plate, the motions produced by the two diagonal halves will be in opposite directions. Specification 912,864 is referred to.