GB258690A - Improvements in or relating to apparatus suitable for use with sound transmitting orrecording apparatus - Google Patents

Abstract

258,690. Graham, E. A. July 2, 1925. Message projected optically on screen adjacent to microphone.-The sound-receiving element of a broadcasting or public address apparatus is provided with a screen on which an image of the matter to be broadcast or amplified is projected by an optical system, thereby enabling a person to read from the image whilst directing his voice towards the sound-receiving element. As shown in Fig. 2, a microphone 3 is mounted in a case 13 on which is placed a lantern 5 for projecting an image on the screen 1. The lantern may be carried by the performer and may project the image on a screen placed directly in front of the microphone, the screen being of silk gauze or the like to enable the sounds to pass. In another modification, the lantern and screen are at one side of the casing 13. Fig. 4 shows one arrangement of the optical projecting system, in which a source of light 1<a> is placed between a reflector 11 and a condenser 12. The light passes through the film 16 to an achromatic objective lens 12a. and thence through an erecting prism 14 to the screen 1. The reading or singing matter is recorded on the film 16 which passes through a guide 15 and is adjusted by a roller 18 and handle 19. Another form of optical system shown in Fig. 5 comprises three plane mirrors 20, 21, 22 arranged with the lantern 5<a> in a casing above the microphone casing 13, and reflecting the light downwards on to a screen 1 in front of the microphone. For making sound records, a trumpet and recording-instrument replace the microphone 3. The Provisional Specification states that the microphone may be of the kind described in Specification 257,309.