Mercuiy-free Xe flat discharge lamps were developed for the use of lighting equipment. The lamps have a simple structure with insulated electrodes and operated with an ac pulse voltage. By adopting 1 mm-wide electrodes, gas pressures of 10kPa or higher, and 50% duty pulse voltage drive, high luminance and high efficacy were achieved. Two types of mercury free Xe flat fluorescent lamps, a single discharge type and a multiple discharge type, were introduced. Luminance of 11,000cd/m
2, luminous flux of 860 lm, and efficacy of 30 lm/W were attained with the 444mm×27mm single discharge type lamp. Luminous flux is sufficient for lighting, although the efficacy is half that of the commercially available Hg fluorescent lamp. A protc-type of a table lamp that utilized a 175mm×110mm multiple discharge type was also made. Luminous flux and efficacy were 850 lm and 21 lm/W, respectively. Illuminance at the position 38cm under the lamp was 1,700 Ix, which is higher than that of a commercially available table lamp.
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