| 摘要 |
An emergency exit sign has a housing in which a pair of LED units are disposed. Each LED unit has two rows of diodes, the rows connected in reverse polarity to an A.C. source so that said rows are illuminated alternatingly. A diffuser plate disposed between the LED units and a stencil plate is formed of a translucent plastic material having a light transmittance frequency to the peak wavelength of light emitted from the diodes. The diodes are exposed to the diffuser plate so that the diffuser plate receives both direct and indirect light therefrom.
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