Patent GB-1084624-A (GB)
Title: Apparatus for selectively deforming a surface of a deformable medium
IPC: G11C13/04
Filed: 1966-02-07
Abstract: 1,084,624. Modulating light. HAZELTINE CORPORATION. Feb. 7, 1966 [March 2, 1965], No. 5297/66. Heading H4F. [Also in Division H1] A reflective or transmissive optical modulating cell comprises a deformable electrically polarizable medium which is deformed in accordance with a charge distribution which is produced adjacent i.e. in close proximity to but not touching, a surface of the medium, so that a corresponding non-uniform electric field is established through the medium to effect electrical polarization thereof. In a first embodiment, Fig. 1b, the deformable medium 10 e.g. a high-voltage transformer oil, is contained as a thin layer in a substrate container 11, e.g. a glass container, and an electrical charge pattern is deposited on the underside of the substrate 11 by means of a stylus electrode 12 which is drawn over the underside. Substrate 11 serves as a charge storage means and the charge distribution establishes a corresponding non-uniform electric field at least a portion of which passes through medium 10, thereby effecting a correspondingly non-uniform electrical polarization of the medium and resulting deformation of a surface thereof. Medium 10 may be of polar or non-polar material. To concentrate the electric field so that it passes only through medium 10 a conductive surface (15) applied to a support (16), Fig. 3, not shown, may be disposed adjacent the upper surface of medium 10 and coupled to a source of given potential. In a further embodiment, Fig. 5, a conductive coating 15 is interposed between deformable medium 10 and substrate 11<SP>1</SP> so as to be contiguous with the lower surface of medium 10, i.e. in direct contact or insulated from direct contact with medium 10 by a thin protective coating of plastic, glass or varnish. Substrate 11<SP>1</SP> does not serve as charge storage means in this embodiment, instead a separate surface 17 adjacent the upper surface of medium 10 performs this function. This embodiment is particularly useful as a reflective type light modulator. In a further embodiment, Fig. 6, a positive charge distribution is produced on the underside of the substrate 11<SP>11</SP> by means of the phenomenon of secondary electron emission using electron gun 18, and the support 16 with its conductive surface 15 rests directly on the lip of substrate 11<SP>11</SP> and may be hermetically sealed thereto. Thus the atmospheric environment surrounding the electron gun 18 may be separated from that which exists in the space between the upper surface of medium 10 and conductive surface 15. If substrate 11<SP>11</SP> is non-conductive the positive charge distribution is stored until erased by impinging electrons, or if it is slightly conductive the charge distribution leaks away. A complete information display system, Fig. 7, comprises a cathode-ray tube 20 having two separate compartments hermetically sealed from one another. A first compartment is formed by substrate 11<SP>11</SP> and the face of the tube 20 and contains deformable medium 10 and conductive surface 15. The second compartment comprises electron gun 18, aperture mirror 21 and a set of Schlieren bars 22 which co-operate with light source 23, 24 and 25, mirrors 21 and 28, bars 27 and screen 29 to form a Schlieren projection system. Instead of a Schlieren system a phasecontrast system may be employed. Instead of a transmissive-type modulator a reflective-type modulator may be employed in the information display system, Fig. 8, not shown.