| 摘要 |
1,186,207. Optical recording. NORTON RESEARCH CORP. 20 Oct., 1967 [1 Nov., 1966; 22 Dec., 1966], No. 47760/67. Heading G5R. Sound or other data (e.g. television signals) is recorded on photographic film 10 by an electroluminescent junction diode 14 formed by a base crystal and a layer of opposite-type impurities, the diode emitting light 28 over an area at least 0.001 inch wide, measured in the direction of relative movement, and being spaced less than 0À004 inch from the film, the light striking the film having a peaked transmission (exposure) curve of width less than 0.003 inch at 80% maximum intensity and more than 0.002 inch at 50% maximum intensity. The diode is preferably of SiC with a P-type layer on an N-type base and the light-emitting edge polished. The diode current from unit 26 is such that maximum light corresponding to maximum signal intensity is still on the linear part of the exposure v. diode current curve. The gain of the amplifier stage may be linear but preferably increases with frequency to extend the upper frequency limit, e.g. to 7 kHz. |
