Patent ID: 7622867

Claim:
A cold cathode fluorescent lamp, comprising: a working gas; a transparent tube receiving the working gas therein, the transparent tube having an inner surface and an outer surface; a fluorescent layer formed on the inner surface of the transparent tube; a cold cathode disposed at one end of the transparent tube; an anode disposed at the other end of the transparent tube; and a filter film formed on the outer surface of the transparent tube, wherein the filter film is a UV-IR light cut filter film having a stack structure following a formula of 0.5(0.5HL0.5H) 2 ×1.666(0.5LH0.5L)×1.4(0.5LH0.5L) 6 ×1.6(0.5LH0.5L)×1.8(0.5LH0.5L) 8 , wherein H represents a base thickness of a high refractive index layer which is equal to one fourth of a central wavelength associated with the filter film, L represents a base thickness of a low refractive index layer which is equal to one fourth of a central wavelength associated with the filter film, the expression of 0.5HL0.5H represents a first filter cavity consisting of two high refractive index layers and a low refractive index layer sandwiched between the high refractive index layers, the expression of 0.5LH0.5L represents a second filter cavity consisting of two low refractive index layers and a high refractive index layer sandwiched between the low refractive index layers, the superscripts represent the numbers of repetition of the filter cavities, and the numbers before the parentheses represent thickness times for the respective filter cavities.