| 摘要 |
774,753. Discharge lamps. PHILIPS ELECTRICAL INDUSTRIES, Ltd. June 27, 1955 [June 30, 1954], No. 18499/55. Drawings to Specification. Class 39(1). [Also in Group XI] In a lighting fitting (see Group XI) the light source may be a low-pressure sodium vapour discharge lamp surrounded by an envelope containing nitrogen, the envelope being surrounded by an evacuated double-walled glass sheath, or it may be a fluorescent lamp comprising a tube having two superposed layers of fluorescent material, the inner layer extending only part way around the tube to provide a lengthwise strip covered by one layer only, this strip in operation being brighter than the remaining part of the tube. |
