| 摘要 |
304,848. Mittell, B. E. G., Whitaker, A., and Gramophone Co., Ltd. Oct. 31, 1927. Optical records and apparatus.-Sound is recorded on transparent material such as celluloid by impressing by a smooth pointed stylus without removing any material, and such record is reproduced or duplicated by optical-electric means. If the blank is supported on a rigid support, an upstanding ridge is formed on each side of the sound groove, but if supported on a yielding support, the stylus depresses the blank below the trace into the support to form a bulge. Figs. 3 and 8 show means for reproducing a record 4 formed by depressing the trace into the support so as to form a bulge 6 on the back of the blank. The face of the blank is flooded with celluloid solution to fil up the trace, and the record if of disc form is rotated and traversed so that a parallel beam of light is 'directed through the bufge 6 and is focussed thereby on to, and transversely of, a slit 7 in a plate 8. The focussed beam which moves lengthwise of the slit 7 in accordance with the formation of the bulge 6 passes through a neutral tinted wedge 9, preferablv associated with a plain wedge 11 and falls with varying effect due. to the wedge, 9 on a photoelectric cell 10 which operates a sound emitter or an electromagnetic recorder for making a record. In reproducing a record with upstanding ridges on each side of the trace us produced by recording on a blank on a rigid support, the beam which is spread by the concave form of the trace is directed through a lens to focus it on the slit, and polarizers may be arranged in the path of the beam in front of and behind the slotted plate. Black lines may be produced on the record on each side of the trace by applying ink: this will not Bow into the polished indented trace, and a groove may be depressed between successive traces to limit the flow of the black lines in the other direction. A matt surface record facilitates the application of the black lines. |
