FLUORESCENT LAMP

PURPOSE:To obtain a light source for measuring the color of an object emitting fluorescence by the ultraviolet radiation by providing a single-layer fluorescent screen coated with a mixture of the specific first-third phosphors on the inner face of a glass tube with the specific density. CONSTITUTION:A phosphor with the peak wavelength of the emission spectrum of 350-380nm and the half-value width of 50-90nm is made the first phosphor, a bivalent Eu-activated alkaline earth metal halophosphate phosphor with the peak wavelength of the emission spectrum of 470-500nm and expressed by the formula is made the second phosphor, a phosphor with the peak wavelength of the emission spectrum of 620-640nm and the half-value width of 120-150nm is made the third phosphor, a mixture of the three phosphors is coated on the inner face of a glass tube with the density of 3.4-4.6mg/cm to form a single-layer fluorescent screen. The mixing ratios of the phosphors are set within the range of the first phosphor 10-33wt.%, the second phosphor 30-50wt.%, and the third phosphor 60-17wt.%.