Metal halide lamp with enhanced red emission
OwnerTimothy Lee Kellyinventor
Life of this patent
Estimating the term…
Abstract
A metal halide lamp with red emission equivalent to or exceeding that of a blackbody source of equal correlated color temperature. A metal halide chemistry containing CaI2 plus a complexing metal halide of AlI3 or GaI3 is used to substantially increase red emission of a metal halide lamp. The inclusion of TlI in the fill chemistry is also important in influencing Ca to preferentially emit atomic and molecular red radiation of the visible spectrum while suppressing blue radiation. Optionally, a shroud of neodymium doped glass is also used to significantly filter transmission of yellow light, thereby further improving the proportion of red emission while maintaining a sufficiently white color and good general color rendering.
Claims13
A metal halide lamp having superior red rendering characteristics, said lamp comprising:
- an arc tube formed of a material transmissive to visible radiation;
- and
- a fill of metal halides in said vessel, said fill comprising at least one member selected from the group consisting of CaI2, CaBr2 plus at least one member selected from the group consisting of AlI31 AlBr3, GaI3, GaBr3 plus at least one member selected from the group consisting of TlI and TlBr;
- and
- discharge electrodes disposed at opposite ends within said arc tube.
A metal halide lamp having superior red rendering characteristics, said lamp comprising:
- an arc tube formed of a material transmissive to visible radiation, said material being either polycrystalline alumina, sapphire or quartz;
- and
- a fill of metal halides in said vessel, said fill comprising at least one member selected from the group consisting of CaI2, CaBr2 plus at least one member selected from the group consisting of AlI3, AlBr3, GaI3, GaBr3 plus at least one member selected from the group consisting of TlI and TlBr;
- and
- said fill further comprising mercury and either Ar or Xe;
- and
- wherein the CaI2 or CaBr2 or both are in a molar quantity between about 10 and 75% of the total molar quantity of the total halides;
- and
- wherein the AlI3 or AlBr3 or both are in a molar quantity between about 2 and 50% of the total molar quantity of the total halides;
- and
- wherein the TlI of TlBr or both are in a molar quantity between about 5 and 50% of the total molar quantity of the total halides;
- and
- wherein said fill further comprises at least one of the elements of Dy, Ho, Tm, Na, Li, Cs;
- and
- discharge electrodes disposed at opposite ends within said arc tube.
Dependencies are inferred from the claim text.