| 摘要 |
<p>This invention provides a low pressure mercury vapor electric discharge lamp composed of a glass bulb whose inner surface is coated with a fluorescent material film, the fluorescent material film contains a fluorescent material, pyrophosphate having an average grain size of 3.0 mu m or less and preferably 1.0 mu m or less, at least one of alkaline earth metal salt and nitrate, and a boric acid compound. According to the above arrangement, there can be obtained a low pressure mercury vapor electric discharge lamp having an improved fluorescent material film adhering strength, an improved total beam of light, a high beam of light maintaining ratio and a less amount of blacking. <IMAGE></p> |
