| 摘要 |
A low-pressure mercury vapor discharge lamp having a satisfactory color rendition (Ra>/=80), a color temperature of 2800 DEG K. or higher and a color point on or near the Planckian locus. The lamp is provided with a luminescent layer (4) which comprises a. a luminescent rare earth metal metaborate activated by Ce and Mn and having a fundamental lattice Ln(Mg,Zn,Cd)B5O10, where Ln represents the elements Y, La and/or Gd, which borate exhibits red Mn emission, b. a luminescent material activated by Tb3+ and having green Tb3+ emission, c. at least one luminescent halophosphate of the group which comprises the calcium halophosphates emitting white light, activated by Sb3+ and Mn2+ and having a color temperature of at least 2900 DEG K. and blue-luminescing calcium halophosphate activated by Sb3+. The lamps yield a satisfactory rendition of deep red colors (R9>/=60) and have a high luminous flux and a high maintenance of the luminous flux during the life.
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