PURPOSE: To secure such a fluorescent lamp as being ease of control for a light color and color redering properties, etc., yet high in lamping efficiency as well as excellent in the color rendering properties, by covering an inner wall of a glass tube with a mixed phosphor made up of mixing two types of phosphors specified each.
CONSTITUTION: As shown in a general expression (Sr2-xEuxO2).mMgO.n(Al2-y ByO3) and those of x, y, m and n in the expression satisfies each of expressions 0.01≤x≤ 0.2, 0.001≤y≥0.03, and 0.5≤m<2.04≤n<6, a first phosphor composed of alkaline earth metal borate aluminate activated by bivalent europium having a light emitting peak in a wave length range of 480W520nm and a half-value range of 150W120nm and a second phosphor such as, for example, a tin-activated orthophosphoric acid strontium magnesium phosphor having the light emitting peak of the wave length of 620W640nm and the half-value range of 120W160nm are mixed, and this mixed phosphor is applied to an inner wall of a glass tube for coating.
YAMAMOTO TAKASHI
SHIBATA HARUO
