| 摘要 |
639,253. Discharge lamps. BRITISH THOMSON-HOUSTON CO., Ltd. (General Electric Co.). Qct. 31, 1946, No. 32837. [Class 39 (i)] [Also in Group XL (b)] The distance of an object is measured by the time for reflection of visible or near visible light pulses having a duration which is a fraction of the time required for reflection of pulses from the object. Light pulses are produced by spark-discharge under pressure from high-voltage capacitors in a generator 10, described below. The pulses are focused by a mirror 11 into a narrow beam, and light pulses reflected from the object are focused by a mirror 13 on to a photo-electric cell 14 connected to an amplifier 30 to produce a vertical trace B on a cathode-ray indicator 18. The horizontal time-base is synchronized with the initial light-pulses by a photo-cell 20, whereby the position of the trace B along the horizontal trace A indicates .the distance of the object. The light-pulse generator 10 comprises a cylindrical metal container 60, Fig. 2, with a semispherical glass window 61 at one end covering aluminium discharge electrodes 91, 90 connected respectively to the container and a common terminal 80 of four banks of series connected capacitors 73. The case is filled with nitrogen or a rare gas such as neon at 10-100 lbs./sq. in. and the capacitors charged from an A.C. supply through resistors 97 to 10-20 kV, the spark-over voltage being determined by adjusting the electrode gap. By this construction the discharge circuit inductance is only 0.05 ÁH for an effective capacitance of 0.01 Áfd., whereby a steepfronted, short-duration light-pulse having an intensity up to 50 kW is produced.
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