Designs are presented of miniature indicators using either filament lamps or light emitting diodes of different colours showing at a common viewing window. Emphasis is placed on low thermal dissipation, efficiency of light output, long-range wide-angle visibility, compactness, longevity and the need for colour change indication.
A two-colour indicator module developed for the Hydrastep display is explained, and is extended to multi-colour module designs Outlines are given for some applications of such indicators to a variety of problems of display and information transfer.
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References
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HaslerE F, ‘Improvements in or relating to Multi-colour Indicators’. UK Patent Specification No 1202695.
2.
HaslerE F, ‘Multi-colour Indicators’. US Patent Specification No 3568177.
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HaslerE FMartinR E, ‘Hydrastep: A ‘Fail Operative’ Gauge System to replace Visual Boiler Water Level Gauges’Measurement and Control, Vol 4, No 12, December 1971.
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SmithW, ‘Lighted Switching Devices’. Electronics World, October 1967, pp. 40–43.
