INTERNALLY ILLUMINATED DISPLAY DEVICE AND PLANAR LIGHT SOURCE DEVICE

摘要

PROBLEM TO BE SOLVED: To constitute an internally illuminated display device which vividly displays an indication mark even in an environment having a limited visibility range independently of the cause of the limitation and which is quickly repaired or has a fluorescent lamp quickly replaced in the case of operation abnormality.

SOLUTION: The internally illuminated display device has a light-transmitting display plate illuminated from the inside by a planar light source device provided with a plurality of fluorescent lamps. The lamps that have various color rendering functions are installed in the same enclosure so that a variety of color rendering properties are demonstrated. The display device is provided with a life monitor means which detects an operation abnormality shown by at least one fluorescent lamp which has reached the last stage of its rated lifetime to output a signal as life information.

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