Broadband antireflective and antistatic coating for CRT

摘要

The outer surface of the glass display panel of a cathode ray tube (CRT) is first coated with an antistatic conductive metal salt solution. A water or organic solvent soluble antireflective coating is then applied by conventional means such as spinning, spraying or dipping to the glass display panel over the first coating. The antireflective coating is comprised of either an organic or an inorganic salt, or a polymer. The coated display panel is then baked, followed by thorough washing with either water in the case of an organic or inorganic salt or water soluble polymer antireflective coating, or toluene in the case of a non-water soluble polymer antireflective coating. Washing the display panel partially dissolves the salt or polymer in the antireflective coating more on the outer surface of the coating than on the inner portion of the coat adjacent the glass facelate. Dissolution of a portion of the salt or polymer in the coating produces pores in the coating and variations in coating thickness, thus changing the light refractive index of the coating. A continuous decreasing dissolution rate determined by the extent of washing of the coated display panel provides the coating with a continuous decreasing light refractive index and broadband antireflection (400-700 nm) with a minimum reflectance of 1.0% in the range of 560-650 nm. Knowing the light refractive index of the glass substrate and that of air (typically 1.0), the refractive index of the salt or polymer coating may be established by the extent of dissolution of the coating during washing.