Abstract: A fluorescent lamp includes a tubular glass bulb, an internal electrode provided substantially along the central axis of the tubular glass bulb, a fluorescent layer provided on the inner surface of the tubular glass bulb, and an external electrode provided on the outer surface of the tubular glass bulb, wherein the internal electrode, having a coiled shape, is laid in the tubular glass bulb with an appropriate tension. According to the present invention, it is possible to prevent a sag in the internal electrode from occurring due to a difference in coefficient of thermal expansion between the tubular glass bulb and a metallic member forming the internal electrode, and to prevent either the tubular glass bulb or the internal electrode from being broken because of an excessive stress, thereby overcoming the problem concerning such type of fluorescent lamp.

Abstract: Since the internal electrode of a fluorescent lamp comprises a base portion made from a transparent glass member having substantially the same thermal expansion coefficient as that of a tubular glass bulb and shaped like a pipe or rod and a conductive and transparent film formed on the surface of the base portion, the thermal expansion coefficient of the internal electrode is made equal to that of the tubular glass bulb to prevent damage caused by temperature variations, and the entire internal electrode 4 is transparent so that all the beams from the fluorescent film can be radiated to the outside without being shaded.

Abstract: An apparatus for correcting the quantity of light from an optical printer arranged a plural number of luminous elements therein, which comprises a producing circuit for producing a plural number of timing signals of different pulse widths and output timing, and a combining circuit for combining the timing signals according to the correcting data, thereby driving the respective luminous elements based on a correcting signal obtained by combination thereof.

Abstract: The present invention concerning the Optical Identification Card System is provided with an individual card which emits infrared light modulated by the individual code and a detector which receives this infrared modulated light and detects the individual code. When a request signal is radiated from this detector as infrared light from the above within the prescribed light-emitting area, the said infrared modulated light is radiated from the individual card within the light-emitting area and thus the individual code is detected by the detector. Then the detected individual code is identified by the identifier, and on the basis of this identification result, the terminal equipment related to the holder of the individual card is actuated, thereby automatically locking and unlocking the door.

Abstract: An epitaxial wafer of a compound semiconductor comprising a single crystalline semiconductor substrate consisting of GaP and an active layer consisting of GaAs.sub.1-x P.sub.x, having a mixed crystal ratio (x) in the range of from 0.5 to 1 is used for an LED. According to the present invention, between the single crystalline semiconductor substrate and the active layer, a light-absorbing layer consisting of GaAs.sub.1-x P.sub.x having the mixed crystal ratio (x) smaller than that of the active layer, is formed to suppress the reflection of light from the surface of the substrate.