GB190728561A - Improvements relating to Means for Recording and Reproducing Sounds. - Google Patents

Abstract

28,561. Holden, W. H., and Hansard, A. G. Dec. 28. Optical instruments.- In apparatus in which a photographic record is obtained of the variations in intensity of a beam of light in accordance with vibrations produced b y sound waves; the photographic impressions are made of variable opacity and constant in width. Positioning means are employed to cause the beam of light to move in a direction non-coincident with the movement of the sensitive record, so that practically the whole surface of the record may be utilized. The sound waves vibrate a shutter o, Fig. 1, either by a diaphragm n and lever m, or by a telephone transmitter and electro-magnets. The shutter o, Figs. 6 and 7, is normally held by a spring p over an aperture q' in a fixed diaphragm q. The rays of light pass through lenses j, Fig. 1, and the shutter o and fall on a film f ; a viewing-aperture j<1> is provided in the lens cell. The positioning- means comprise a disk a with equidistant radial slots b rotating before a camera front having a curved slit d ; the width of the record may be varied either by using a disk with more radial slots b and partly masking the slit d, or by moving the axis c of the disk a nearer the slit d and altering the curvature of the slit. A series of curved records h are thus formed, but the record may be made continuous by oscillating a disk having only one radial slot b in front of the slit d. By making the slit d straight in this latter case, a straight record is produced ; by traversing an endless band with transverse slots across a camera front having a slit lengthways of the band, a record with straight parallel bands is produced. A traversing or oscillating band or carrier having a slit of the required shape may be used without any intervening screen. In a modification, Fig. 9, lenses coincide with apertures b in the disk, and are moved in front of the slit d, and, instead of devices having apertures, material of a transparent nature may be utilized, with parts rendered opaque.