Loading patent…
AssigneeUshiodenki Kabushiki Kaisha
InventorsTatsushi Igarashi, Osamu Mizuno, Kazuo Nakamura, Shoichi Mayama
Estimating the term…
A discharge lamp in which ultraviolet radiation of short wavelengths can be advantageously cut and in which the amount of emitted light (i-line) of 365 nm wavelength can be increased is achieved according to the invention by providing a quartz glass arc tube that is coated with a plurality of coating layers which include a layer which has Ta.sub.2 O.sub.5 as the main component, and at least one additional coating layer which has a refraction coefficient which differs from the refraction coefficient of the coating layer having the Ta.sub.2 O.sub.5 main component. These layers act to prevent the reflection of light with a wavelength of 365 nm which is incident on the coatings on the arc tube and to cut at least 50% of the ultraviolet radiation having wavelengths of 230 nm or less. According to the invention, the coating layers can be provided on the outer side of the arc tube, on the inner side of the arc tube, or on both on the inner and outer sides of the arc tube.
A discharge lamp comprising an arc tube made of quartz glass on which a plurality of coating layers are provided as a means for preventing reflection of light with a wavelength of 365 nm which is incident on the arc tube and for cutting at least 50% of ultraviolet radiation having wavelengths of 230 nm and below from light emitted from the arc tube;
Discharge lamp comprising an arc tube made of quartz glass on which a plurality of coating layers are provided as a means for preventing reflection of light with a wavelength of 365 nm which is incident on the arc tube and for cutting at least 50% of ultraviolet radiation having wavelengths of 230 nm and below from light emitted from the arc tube;
Dependencies are inferred from the claim text.