UV-screening substance, useful in gas discharge lamp and lighting device, comprises a fine zinc oxide particle and indium that is doped into the fine zinc oxide particle

摘要

UV-screening substance (A) comprises a fine zinc oxide particle as a main component, which is composed of a stable solution with a wurtzite crystal structure, and indium, which is doped into the fine zinc oxide particle, where the half-width of the diffraction peak of the (110)-plane at a diffraction angle of 2theta is 0.4-0.1[deg], if (A) is subjected to X-ray diffraction analysis. Independent claims are included for: (1) a gas discharge lamp comprising: either a light-transmitting flask, a light-emitting unit that is contained in the light-transmitting flask, and an UV-screening filter that is formed on the light-transmitting surface of the substrate by using (A), or an UV-screening filter exhibiting an UV-screening film that is formed by applying (A) on the surface of the light-transmitting substrate, where (A) is predominantly composed of fine zinc oxide particle doped with indium, and the UV-screening filter exhibits a screening ratio of = 90% for screening the light with a wavelength of 390 nm at the UV-screening filter comprising a light-transmitting substrate and exhibiting a transmittance of = 85% for the entire visible light with a wavelength of = 500 nm to pass through, where the wavelength of light with a transmittance of 50% at the end of the short wavelength range of the light absorption is 405-425 nm, and the gas discharge lamp comprises a light-emitting tube, whose outer circumferential surface is covered by the UV-screening filter; and (2) a lighting device comprising: either a device body, a light source that is attached to the device body, a light-transmitting cover that is attached to the device body in such a manner that it conceals the light source, and an UV-screening filter that is formed on the light-transmitting surface of the substrate by using (A), or a device body and a gas discharge lamp that is attached to the device body, or a device body, a light source that is attached to the device body, a light-transmitting glass cover that is attached to the device body such that it conceals the light source, and an UV-screening filter exhibiting an UV-screening film, which is formed as a light-transmitting glass substrate by applying (A) on the surface of the light-transmitting glass cover, where (A) is predominantly composed of fine zinc oxide particles that are doped with indium and the UV-screening filter exhibits a screening ratio of = 90% for screening the light with a wavelength of 390 nm at the UV-screening filter comprising the light-transmitting glass substrate and exhibiting a transmittance of = 85% for the entire visible light with a wavelength of = 500 nm to pass through, where the wavelength of the light with 50% transmittance, at the end of the short wavelength range of the light absorption, is 405-425 nm.