| 摘要 |
1497586 Monitoring surface resistivity SIERRACIN CORP 5 Dec 1975 49970/75 Heading G 1A A process for monitoring the production of a transparent metallized substrate, being prepared by vacuum depositing metal on a transparent film, comprises measuring the surface resistivity of the deposit by irradiating it with electromagnetic radiation in the wavelength range 1.5 to 3.0 microns and measuring the percentage transmission or reflection of radiation from the metallized substrate. Light from an incandescent source 30 having a brightness temperature greater than 800‹C is directed through the metallized substrate and an optical interference band-pass filter to a lead sulphide detector 31. The detector output passes via a filter and 2-pole narrow pass preamplifier 35 to a rectifying amplifier 32 where it is compared with a reference signal on line 34. The source 30 may comprise an optical chopper. |
