Metal halide lamp
AssigneeKoninklijke Philips Electronics N.V.
InventorsPeter Jozef Vrugt, Changlong Ning
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Abstract
The invention provides a metal halide lamp 1 wherein the concentration of the filling components fulfill a condition according to claim 1. Such a lamp is found to be a good alternative to existing high-pressure discharge lamps (Ceramic Discharge Metal halide lamps) based on rare earth fillings or other metal halide fillings. In addition, such a lamp can be dimmed without a substantial shift of the color point. Such a lamp can also have photometric properties that are substantially independent of the arrangement of the lamp and/or the external temperature.
Claims13
A metal halide lamp (1) comprising a ceramic discharge vessel (3), which discharge vessel (3) encloses a discharge volume (11), comprises two electrodes (4, 5), and contains an ionizable gas filling, the ionizable gas filling comprising one or more components selected from the group consisting of LiI, NaI, KI, RbI, CsI, MgI2, CaI2, SrI2, BaI2, ScI3, YI3, LaI3, CeI3, PrI3, NdI3, SmI2, EuI2, GdI3, TbI3, DyI3, HoI3, ErI3, TmI3, YbI2, LuI3, InI, TlI, SnI2 and ZnI2, wherein the concentration h of the respective components in the discharge vessel (3) in μg/cm3 fulfill the equation:
- log h=A/Tcs2+B/Tcs+C+log z,
- wherein Tcs is the coldest spot temperature of discharge vessel (3) in Kelvin during nominal operation of the lamp (1), wherein A, B and C are defined as follows:
- Component
- A*10−6
- B*10−3
- C
- LiI
- −0.51
- −5.88
- 7.16
- NaI
- −1.30
- −5.82
- 6.99
- KI
- −2.51
- −3.48
- 5.66
- RbI
- −2.04
- −4.95
- 6.48
- CsI
- −1.40
- −5.72
- 7.13
- MgI2
- −1.92
- −4.40
- 8.20
- CaI2
- −3.45
- −5.99
- 6.83
- SrI2
- −1.99
- −9.33
- 8.05
- BaI2
- −2.15
- −10.00
- 8.47
- ScI3
- −17.70
- 18.76
- 0.16
- YI3
- −7.96
- 0.43
- 6.41
- LaI3
- −4.24
- −4.66
- 6.98
- CeI3
- −3.15
- −7.37
- 9.36
- PrI3
- −1.98
- −7.86
- 8.43
- NdI3
- −4.29
- −4.42
- 6.58
- SmI2
- −1.62
- −11.20
- 9.71
- EuI2
- −1.95
- −10.50
- 8.95
- GdI3
- −9.69
- 4.26
- 3.62
- TbI3
- −9.41
- 4.09
- 3.59
- DyI3
- −11.90
- 6.42
- 4.68
- HoI3
- −9.48
- 3.15
- 5.61
- ErI3
- −12.10
- 6.54
- 5.46
- TmI3
- −3.12
- −5.25
- 7.64
- YbI2
- −1.33
- −10.10
- 8.45
- LuI3
- −9.00
- 3.37
- 5.38
- InI
- −1.30
- −2.02
- 6.11
- TlI
- −1.36
- −2.92
- 7.01
- SnI2
- −1.99
- −1.14
- 6.39
- ZnI2
- −2.58
- 0.65
- 5.23
- and wherein Tcs is at least 1200 K and z is between 0.001 and 2.
Dependencies are inferred from the claim text.