CN101371330A - Gas-filled shroud of electric arc tube - Google Patents

Abstract

A lamp is provided having an arctube having a light-transmitting envelope. The arctube is surrounded by a gaseous medium confined by a containment envelope such as a hermetic shroud. The gaseous medium is preferably He or H2 or Ne or another gas whose thermal conductivity is greater than that of N2 at 800 DEG C., or a mixture thereof, to help cool the arctube. The inside and/or outside of the shroud may be coated with a diffusion barrier. To help cool the hot spot of the arctube the gap between the shroud and the envelope can be made small, the portion of the shroud wall near the arc can be thickened, the arctube can be offset above the longitudinal axis of the shroud, and the return lead of the arctube can be located between the shroud and the arctube.

Description

The gas-filled shroud of electric arc tube

The application requires in the U.S. Provisional Patent Application No.60/717 of submission on September 14th, 2005, and 087 right is incorporated herein it in full as a reference.

Technical field

Present invention relates in general to discharge lamp, more specifically, relate to the have electric arc tube discharge lamp of (arctube), the refrigerating gas that this electric arc tube is closed in the containment vessel (containment envelope) surrounds.

Background technology

The optical efficiency of existing quartz discharge head lamp is relatively poor, and this is because must absorb a large amount of light that electric arc tube sends (about 30% or more than) in headlamp system, mainly to be avoided unwanted dazzle in the head lamp light beam.Because various influences, comprise the crooked of the light scattering that causes in liquid metals halide pond (liquid metal halide pool), electric arc and, make light source seem obviously greater than electric arc itself from the reflection on electric arc tube and guard shield surface.Head lamp for example auto bulb needs very little electric arc tube, and the apparent source of auto bulb is about 5mm or the following and about 2mm of diameter or following.In order to obtain the good optical performance, it is about 2-3mm or following that expectation makes the overall diameter of electric arc tube.Had the instruction of closing the minimum ceramic arc tube of inner and outer diameter, WO 2004/023517 A1 for example, but this electric arc tube has high internal temperature.When the overall diameter of the ceramic arc tube of working under about 35W is about 5mm for about 2mm and gap length (gaplength), the hot-zone temperature of ceramic arc tube upper inside surface (hot spottemperature) (T3) reaches and is higher than 1500K, be generally about 1700K, however one of long-life requirement of ceramic arc tube for T3 is lower than about 1500K.Need provide in the outside of ceramic arc tube the T3 temperature is reduced to heat of cooling environment below the 1500K.

Summary of the invention

A kind of lamp, it comprises electric arc tube, this electric arc tube has printing opacity shell and a pair of spaced electrode.The gas medium that electric arc tube is closed in its outside containment vessel surrounds.The 10mol% at least of gas medium is by He or H in the time of 25 ℃ ₂Or when Ne or 800 ℃ thermal conductivity greater than N ₂Other gas or their mixture provide.Containment vessel can be guard shield.Gap between printing opacity shell outer surface and the guard shield inner surface is preferably less than the overall diameter of printing opacity shell.The wall thickness of guard shield is preferably greater than 10% of guard shield interior diameter.Electric arc tube has the electric arc part.The wall thickness of the guard shield first of contiguous electric arc part can be greater than the wall thickness of the guard shield second portion of being separated by with described first.(a) wall thickness of guard shield or (b) thickness in gap or (c) wall thickness of guard shield and the thickness in gap can change the axial-temperature gradient effective and efficient manner of advantageously improving electric arc tube between electric arc tube and the guard shield.The electric arc tube longitudinal axis can be to azimuth temperature gradient (azimuthal temperature gradient) the effective and efficient manner vertical off setting guard shield longitudinal axis that advantageously improves electric arc tube.

Description of drawings

Fig. 1 diagram is according to lamp of the present invention; With

The lamp of Fig. 2 diagram alternate embodiment according to the present invention.

Fig. 3 diagram is according to lamp of the present invention, wherein only along the guard shield wall thickness in the electric arc tube zone of contiguous arc gap (arc gap).

The lamp of Fig. 4 diagram alternate embodiment according to the present invention is wherein only along the guard shield wall thickness in the electric arc tube zone of contiguous arc gap.

Fig. 5 diagram is according to lamp of the present invention, and wherein electric arc tube is installed in the position of departing from the guard shield center vertically upward.

Fig. 6 diagram wherein reduces along the electric arc tube zone electric arc tube outer surface of contiguous arc gap and the gap between the guard shield inner surface according to lamp of the present invention.

Fig. 7 diagram wherein is positioned at electric arc tube position vertically upward in the electricity of electric arc tube backflow lead-in wire (electrical returnlead) gap between electric arc tube outer surface and guard shield inner surface according to lamp of the present invention.

Fig. 8 is for containing N ₂The thermal conductivity curve chart of admixture of gas.

Fig. 9 a diagram is according to lamp of the present invention, and wherein electric arc tube coaxial (concentrically) is positioned in the asymmetric guard shield.

Fig. 9 b diagram is according to lamp of the present invention, and wherein the longitudinal axis of electric arc tube is positioned at asymmetric guard shield longitudinal axis position vertically upward.

Figure 10 shows the guard shield sectional view along Fig. 9 a line 10-10.

Figure 11 shows the alternate embodiment of guard shield shown in Figure 10.

Figure 12 shows the alternate embodiment (not showing section line) of guard shield shown in Figure 10.

Embodiment

In explanation subsequently,, be meant preferably to be at least 5 and preferably be not more than 25 individually and independently when given preferable range for example during 5 to 25 (or 5-25).

With reference to figure 1, show high-intensity discharge lamp 10 with electric arc tube 12, metal halide lamp for example, described electric arc tube 12 are contained in the seal protection shell for example in the sealed shield 14.Electric arc tube 12 comprises the discharge space 34 that holds conventional filler.Guard shield 14 holds gas medium or gas or the refrigerating gas or the refrigerating gas medium 38 of filling refrigerating gas space 60, comprises gap or spacing 62 between electric arc tube 12 or printing opacity shell 16 outer surfaces 66 and the guard shield inner surface 64 in the zone around the 60 preferred discharge spaces 34 between electrode 26,28 ends of described refrigerating gas space.Gap 62 is preferably the annular gap and can has even or uneven thickness.Electric arc tube 12 comprises and is preferably the printing opacity shell 16 (among Fig. 1 be shown pipe) of column or replaceability ground for prolate ellipsoid shape, spherical or other shape, this printing opacity shell hermetic seal and two ends are blocked at least in part by first column 18 and second column 20, described column is preferably column, but also can be constriction (pinched) solid of approximate rectangular or other shape in cross section.Column 18,20 can be quartz or pottery, but also can be other material, for example molybdenum or other high-temperature metal known in the art.Electric arc tube 12 and printing opacity shell 16 can be quartz or the transparent or semitransparent material of other high temperature, but preferably ceramic, and this is because pottery is lower and have high temperature extremes to the permeability of refrigerating gas 38, thereby can realize less electric arc tube 12.Lamp 10 also comprises the electric conductor 22,24 that is electrically connected with spaced electrode 26,28 respectively.Electric conductor 24 is fixed on the bending end part of down-lead bracket 30, and described down-lead bracket links to each other with pedestal 32 in a usual manner and for example quartz or earthenware 36 partly surround by electric insulating tube.Although show that down-lead bracket 30 is positioned at the outside of guard shield 14 and forms the both-end guard shield, in the structure of some lamps, down-lead bracket also can be positioned at the inside of guard shield 14 and form single-ended guard shield.In single-ended guard design, for example shown in Figure 7, electric conductor 22 and 24 both near the same end feedthrough guard shield 14 of pedestal 32.Except the application illustrated, above-mentioned lamp 10 and parts thereof are for conventional and be known in the art.

The present invention can be used for head lamp and automobile discharge head lamp, but also can be used for all high-intensity discharge lamps and not too preferred incandescent lamp and LED lamp, and has any light source shell, as described in the present application, when the light source shell by the passive cooling of hermetic seal gas or fitted tightly the guard shield of light source shell or when having the guard shield of heavy wall or being had the passive cooling of combination of any described advantage, can make the light source shell littler and brighter.In automobile discharge head lamp is used, comprise shell or manage 16 electric arc tube 12 and preferably make by polycrystal alumina, polycrystalline YAG or other potteries known in the art.Spacing between the electrode tip or arc gap are preferably 1-7,2-6 or about 4mm, and lamp is preferably worked under 15-1000,15-500,15-100,20-60,30-40 or about 35W.

The interior diameter of shell 16 preferably less than 2.6,2,1.5,1.4,1.3,1.2,1.1,1,0.9,0.8,0.7mm, the wall thickness of pipe or shell 16 is preferably 0.2-1,0.3-0.8 or about 0.4mm.The pipe or the overall diameter of shell 16 are preferably less than 6,5,4,3,2.5,2.3,2.2,2.1,2,1.9,1.8,1.7,1.6,1.5,1.4 or 1.3mm.The ratio of spacing or gap 62 (guard shield 14 inboard 64 and manage between 16 outsides 66) and the overall diameter of shell 16 is preferably less than 2,1.5,1,0.8,0.7,0.6,0.5,0.4,0.3,0.2 or 0.1 (for He or other useful gas, needn't be the guard shield that fits tightly).If gap 62 is thickness uniform circular gap, then it is preferably less than 2,1.5,1,0.8,0.7,0.6,0.5,0.4,0.3,0.2 or 0.1mm.Guard shield 14 is preferably cylindric, and preferably have evenly or basic about 0.5-6 uniformly or 1-3mm or preferably about 2mm wall thickness and preferably have 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 150% or 200% wall thickness greater than the guard shield interior diameter, and preferably made by quartz, perhaps for example alumina silicate glass (for example GE 180 types) or sufficiently high other glass of temperature extremes are made by hard glass under the enough low situation of temperature.GE 180 type glass have following composition (%) usually: 60.3 SiO ₂, 14.3Al ₂O ₃, 6.5 CaO, 0.02MgO, 0.21 TiO ₂, 0.025 ZrO ₂,＜0.004 PbO, 0.02Na ₂O, 0.012K ₂O, 0.03 Fe ₂O ₃, 18.2 BaO, 0.001 Li ₂O, 0.25 SrO.Guard shield preferably has less than 10,8,6,5,4,3,2.8,2.6,2.5,2.4,2.2,2,1.9 or the interior diameter of 1.8mm and less than 20,15,12,10,8,7,6,5.5,5.3,5.2,5,4.8,4.6,4.4,4.2,4 or 3.8mm or greater than 20,15,12,10,8,7,6,5.5,5.3,5.2,5,4.8,4.6,4.4,4.2,4 or the overall diameter of 3.8mm.The interior diameter of guard shield 14 is preferably less than 5,4,3,2,1.5,1.2,1.1,1,0.8,0.6,0.5,0.4,0.3 or 0.2mm and greater than pipe 16 overall diameter.Difference between the interior diameter of the overall diameter of shell 16 and guard shield 14 is preferably less than 4,3,2,1,0.8,0.5 or 0.3 times of shell overall diameter.Electric arc tube 12 and pipe 16 can be guard shield 14 between two parties or can in guard shield 14, depart from or the off center.Electric arc tube 12 and/or guard shield 14 can be non-cylindric, and in this case, above-mentioned size is measured at the midplane place between two electrode ends.

Space gassy medium between guard shield 14 and the electric arc tube 12 or gas or refrigerating gas 38, described gas is preferably Ne, perhaps H more preferably ₂He or 800 ℃ of following thermal conductivitys greater than N ₂Other gas or their mixture, pressure is preferably 0.01-10 or 0.1-10 or 0.1-5 in the time of 25 ℃, 0.3-3 more preferably, 0.5-2 more preferably, more preferably about 0.6-1.5, more preferably about 0.8atm.Owing to have high thermal conductivity, described gas medium plays the work of cold gas in order to help cooling electric arc tube 12.Traditional filler in the hermetic seal guard shield is generally the N that pressure is 0.1-1.5atm ₂Gas.N ₂Molecule is lower than than lighter-than-air gas Ne (amu=20), He (amu=4) or H owing to molecular weight big (amu=28) has ₂(amu=2) thermal conductivity.Gas conduction rate (W/m-K) when 800 ℃ (representative temperature of gas 38) of most critical is N ₂=0.07, Ne=0.12, He=0.38 and H ₂=0.46.As shown in Figure 1, electric arc tube 12 be closed in its outside containment vessel for example the gas medium in the guard shield 14 38 surround.In the time of 25 ℃ (a) mole of at least 10 of preferred gas medium 38,20,30,40,50,60,70,80,90,95,97,99 or 99.9% and (b) pressure by Ne or He or H ₂Or 800 ℃ the time thermal conductivity greater than N ₂Other gas or their mixture provide, more preferably provide by He.Gas medium 38 parts of one of non-described cold gas are preferably N ₂

One of function of gas 38 in the guard shield 14 is the gas electrical breakdown between electric arc tube 12 external electric go between when suppressing ballast (ballast) and applying high pressure (the highest about 25kV) firing pulse.Because He has very high ionization potential, thereby He gas can fully suppress to puncture.In some structures of lead-in wire 22 and 24,, except that cold gas 38, may also need to comprise N in order to suppress the electrical breakdown between the lead-in wire in the lamp ignition process ₂The gas dividing potential drop.In this case, should be with respect to cold gas 38 (preferred Ne, H ₂Or He) N ₂Dividing potential drop is restricted to and suppresses to puncture required minimum N ₂Amount, thus the maximum that obtains refrigerating gas is cooled off benefit.Be desirably in the overall thermal conductance maximization of gas in the zone between the electric arc tube outside and the guard shield inboard, wherein by document (Thermal Conductivity of Gases and Liquids, N.V.Tsederberg, The M.I.T.Press, 1965, pp.144-165) overall thermal conductance of admixture of gas has several different evaluation methods as can be known, and great majority have following form:

$\mathrm{\λ}=\frac{{\mathrm{\λ}}_1}{1+A_{12}\frac{x_1}{x_2}}+\frac{{\mathrm{\λ}}_2}{1+A_{21}\frac{x_1}{x_2}}$ (equation 1)

λ wherein ₁And λ ₁Be thermal conductivity, x ₁And x ₂For each forms the percentage by volume of gas; A ₁₂And A ₂₁For can be with the quality of forming and the coefficient of diameter and variations in temperature.On 146 pages of Tsederberg, provide following A ₁₂Typical expression formula (A ₂₁Have complementary form):

$A_{12}=\frac{1}{\sqrt{2}}\left(\frac{d_1+d_2}{2d_1}\right)\sqrt{\frac{m_1+m_2}{m_2}}$

Can utilize equation 1 to draw as shown in Figure 8 admixture of gas thermal conductivity curve, in Fig. 8, compare thermal conductivity and traditional N of admixture of gas ₂The thermal conductivity of gas.Each admixture of gas among Fig. 8 is by the N of certain percentage (0-100%) ₂Gas and as Ne, He or the H of remainder ₂Any mixture is formed in the gas.The thermal conductivity of admixture of gas should exceed N ₂The thermal conductivity of gas self (800 ℃ time be 0.072W/m-K) at least 20%, more preferably 50%, 100%, 200%, 300%, most preferably 400%, make that the thermal conductivity of admixture of gas 38 should be at least 0.086 800 ℃ the time, more preferably 0.108,0.144,0.216,0.288, most preferably be at least 0.359W/m-K.Thereby, pure as can be known He or H ₂Be the refrigerating gas of excellence, Ne is good refrigerating gas in addition.In addition, as shown in Figure 8, to He or H ₂The middle N that adds ₂Even, N ₂Percentage is up to 80% or 90%, and it (is that thermal conductivity obviously surpasses N that refrigerating gas still can be provided ₂The thermal conductivity of self).N in the mixture ₂The percentage of gas should be chosen as and suppress the required minimum percentage of high-voltage breakdown between the described lead-in wire 22 and 24, applies the required ignition voltage of lamp starting between lead-in wire 22 and 24.Thereby provide the maximum cooling advantage of gas.

Although based on thermal conductivity H ₂With He be optimal gas, but the consideration of other design aspect that changes for concrete application with lamp, for example refrigerating gas is enclosed in the guard shield, perhaps prevents the high-voltage breakdown of refrigerating gas in cold gas intrusion electric arc tube or the lamp ignition process, they may be disadvantageous.Think that thermal conductivity is greater than N 800 ℃ the time ₂Any other gas can be used as cold gas.ChemicalProperties Handbook, 1999 have provided the thermal conductivity (function of gas temperature) of 297 kinds of modal inorganic gas and 1296 kinds of organic gass.Following when listing 800 ℃ thermal conductivity surpass N ₂41 kinds of inorganic gas of (800 ℃ time k=0.072W/m-K):

Thermal conductivity during 800 ℃ of molecular formula material titles

H ₂Hydrogen 0.457

He helium-3 0.400

He helium-4 0.378

D ₂O deuterium oxide 0.368

D ₂Deuterium 0.338

H ₃N ammonia 0.200

FH hydrogen fluoride 0.189

B ₂H ₆Diborane 0.179

CH ₄N ₂Ammonium cyanide 0.153

D ₃The heavy ammonia 0.145 of N

B ₄H ₁₀Borine 0.137

B ₂D ₆Deuterium diborane (deuterodiborane) 0.132

CH ₂BO carbonyl monoborane (borine carbonyl) 0.125

H ₄Si silane 0.125

B ₅H ₉Pentaborane 0.125

B ₅H ₁₁Hydrogen pentaborane 0.120

Ne neon 0.117

N ₂O ₄Dinitrogen tetroxide 0.115

H ₂O water 0.108

H ₃NO azanol 0.108

H ₆Si ₂Disilane 0.098

FH ₃Si one silicon fluoride 0.093

B ₃H ₆N ₃Triamine monoborane (borine triamine) 0.087

FNO nitrosyl fluoride 0.086

H ₃P hydrogen phosphide 0.083

F ₃N Nitrogen trifluoride 0.082

CDN cyaniding deuterium 0.082

O ₂Oxygen 0.078

H ₆OSi ₂Disiloxane 0.078

H ₂O ₂ Hydrogen peroxidase 10 .077

CH ₄N ₂O urea 0.077

ClH ₄P phosphonium chloride 0.077

F ₂Fluorine 0.077

N ₂O nitrous oxide 0.077

H ₄N ₂Hydrazine 0.076

NO nitrogen oxide 0.076

F ₂H ₂Si two silicon fluorides 0.076

CHN hydrogen cyanide 0.075

F ₂O fluorine oxide 0.074

NO ₂Nitrogen dioxide 0.074

HNO ₃Nitric acid 0.073

Following thermal conductivity when listing 800 ℃ is at least N ₂31 kinds of organic gass of the twice of (800 ℃ time k=0.072W/m-k):

During 800 ℃ of molecular formula material title minimum temperature maximum temperatures

(K) (K) thermal conductivity

C ₂F ₆Perfluoroethane 195 700 0.272

C ₆H ₁₅N triethylamine 273 1,000 0.266

C ₃H ₇N allylamine 326 1,000 0.214

C ₄H ₆1,3-butadiene 250 850 0.193

C ₃H ₈O methyl ethyl ether 273 1,000 0.191

C ₄H ₈O ethyl vinyl ether 309 1,000 0.185

C ₃H ₁₀N ₂1,2-propane diamine 392 1,000 0.181

CH ₄Methane 97 1,400 0.179

C ₄H ₈Cyclobutane 286 1,000 0.178

C ₄H ₁₀O methyl isopropyl ether 304 1,000 0.175

C ₆H ₁₂Methyl cyclopentane 345 1,000 0.174

C ₄H ₆O divinyl ether 301 1,000 0.166

C ₃H ₆Cyclopropane 240 1,000 0.162

C ₅H ₁₂O methyl isobutyl ether 332 1,000 0.162

C ₄H ₉N pyrrolidines 360 1,000 0.160

C ₄H ₄O furans 305 995 0.156

C ₆H ₁₀O cyclohexanone 400 1,000 0.154

C ₄H ₈O oxolane 338 998 0.154

C ₈H ₁₈O di-secondary butyl ether 394 1,000 0.151

C ₇H ₁₄O diisopropyl ketone 398 1,000 0.151

C ₂H ₄O ₂Methyl formate 300 1,000 0.151

C ₃H ₇N propyleneimine 334 1,000 0.149

C ₅H ₁₀O methyl isopropyl Ketone 368 1,000 0.148

C ₆H ₁₄O normal-butyl ether 365 1,000 0.148

C ₂H ₇N dimethylamine 273 990 0.147

C ₆H ₁₂O ethyl nezukone 387 1,000 0.147

C ₄H ₉NO morpholine 401 1,000 0.146

C ₃H ₄O ₂Vinyl formate 320 1,000 0.146

C ₆H ₁₂O butyl vinyl ether 367 1,000 0.145

C ₃H ₆Propylene 250 1,000 0.145

C ₃H ₆O ₃Trioxane 388 998 0.144

Owing to may on the electric arc tube outside, causing photoresistance and overheated by the deposition simple substance carbon, so organic gas is not preferred usually.

From above-mentioned inorganic gas, get rid of high those of toxicity in the described inorganic gas, for lamp with too expensive those and thermal conductivity not than N ₂Greatly at least 20% (for respect to N ₂Have remarkable advantages) those, be reduced to following gas:

Thermal conductivity during 800 ℃ of molecular formula material titles

H ₂Hydrogen 0.457

He helium-4 0.378

H ₃N ammonia 0.200

B ₂H ₆Diborane 0.179

B ₄H ₁₀Tetraborane 0.137

CH ₂BO carbonyl monoborane 0.125

H ₄Si silane 0.125

B ₅H ₉Pentaborane 0.125

B ₅H ₁₁Tetrahydrochysene pentaborane 0.120

Ne neon 0.117

N ₂O ₄Dinitrogen tetroxide 0.115

H ₂O water 0.108

H ₃NO azanol 0.108

H ₆Si ₂Disilane 0.098

FH ₃Si one silicon fluoride 0.093

B ₃H ₆N ₃Triamine monoborane 0.087

FNO nitrosyl fluoride 0.086

In addition, several favourable alternative gas in this tabulation is difficult to control, for example hydrogen, ammonia etc. in preparation.He and Ne safety, inexpensive, no chemism and be easy to charge in the lamp.He is highly beneficial, and when being preferred refrigerating gas with guard design He when comprising He in the whole useful life at lamp.

N in the time of 25 ℃ ₂The molal quantity and the dividing potential drop of gas (and/or other the high pressure resistant gas except that the cold gas of the present invention's instruction) preferably are not more than 5,10,15,20,25,30,35,40,45,50,60,70,80 or 90% of gas medium 38 total mole numbers or total pressure.The 0.1-90 of preferred gas medium 38 molal quantitys and pressure or 0.1-80 or 0.1-50 or 0.1-30 or 1-20 or 1-15 or 1-5% are by N in the time of 25 ℃ ₂Provide.

Under the working temperature that guard shield 14 is high in the typical case of lamp uses (being generally 400-1000 ℃, more typically about 500-700 ℃), some have the preferred refrigerating gas (H of high thermal conductivity ₂, thermal conductivity is higher than N when He, Ne or other 800 ℃ ₂Gas) minor diameter atom and molecule be easy to diffusion usually and see through quartzy guard shield.Compare with heavier and more disadvantageous gas, less and more favourable cold gas spreads quickly and sees through quartz usually.Usually, in less than 100 hours, the He above 99% loses from the quartzy guard shield with representative temperature (for example 600 ℃) and typical quartz wall thickness (for example 1mm).Since the typical life of lamp be 1000 hours or more than, this He extent of damage is underproof.See through the H of typical guard shield material (quartz and glass) ₂Loss speed is usually lost quite or more deterioration of speed with He, and the loss of Ne and heavier gas is better than He usually but is more disadvantageous refrigerating gas.Several minimizings are refrigerating gas (particularly He and/or H more preferably ₂) method that sees through the divergence loss of guard shield 14 includes but not limited to: the coating that diffusion impervious layer is provided on the inner surface of guard shield 14 and/or outer surface; Perhaps have coating or do not having in mutually nested one or more guard shields of coating, utilizing cold gas is had the quartz material that replaces guard shield 14 than the combination of the doping quartz of hypotonicity or glass or doped-glass or glass and quartz combination thing.Suitable coating compounds comprises film, and perhaps the high temperature film of for example transparent or substantially transparent of dip-coating or sol-gel is effective as diffusion impervious layer to avoid or to avoid substantially or to suppress or reduce substantially the divergence loss of gas medium 38.Fig. 1 shows film 40 on guard shield 14 inboards and the film 42 on the outside.Film 40 and film 42 can be the signal layer coating of the thick tantalum oxide of about 1 μ m or titanium dioxide or aluminium oxide or hafnium oxide or other high temperature transparent material or their combination, perhaps be titanium dioxide or tantalum oxide or aluminium oxide or other high index of refraction high temperature optical thin film layer in conjunction with the multilayer known in the art of replaceability silica or other low-refraction high temperature optical thin film layer (preferred 2-100 layer altogether, more preferably 3-50 layer altogether, more preferably 5-20 layer altogether) interference coatings (interference coating) (tantalum oxide-silica for example known in the art or titanium dioxide-silica interference coatings), described multi-layer interference coating are simultaneously as the diffusion impervious layer of gas 38 with improve antireflection or the wavelength selectivity or the directional selectivity coating of the optical property of lamp.Because the high temperature capabilities of tantalum oxide, in superhigh temperature is used (for example greater than 600 ℃), tantalum oxide is preferable over titanium dioxide, but guard shield 14 can be designed to particularly be enough on its outer surface use the cooling condition operation down of coating of titanium dioxide usually.Can apply multilayer or signal layer coating by CVD or sputter or evaporation or other method known in the art, and can apply signal layer coating by better simply dipping known in the art or method of spray plating.Many glass are usually to He and H ₂More preferably the permeability of refrigerating gas is lower than quartz, and described glass includes but not limited to: soda-lime glass, borosilicate glass, alumina silicate glass and lead glass.Consider in lamp preferred no lead composition and need high temp glass in many application of lamp, alumina silicate glass for example GE 180 type glass is preferred guard shield material.180 ANNEALING OF GLASS temperature are 785 ℃, and this temperature is usually above the maximum temperature (being generally about 500-700 ℃) of guard shield 14 inboards.In the design of lamp, also use aluminosilicate 180 glass usually, and can realize good hermetic seal between the typical molybdenum lead-in wire 22,24 in 180 glass and the design of many electric arc tubes.Thereby the preferred embodiment of holding the He guard shield is the quartzy guard shield through applying, perhaps glass shield more preferably, the glass shield through applying more preferably, or the alumina silicate glass guard shield through applying more preferably.Perhaps; the containment vessel that holds cold gas can be the head lamp reflection shield together with lens and suitable seal; perhaps be enough big and cold guard shield (for example; similar with guard shield 14; the inner surface of different is this guard shield and the outer surface of pipe 16 be separated by at least 0.2,0.4,0.6,0.8,1,2,3,4,5,6,8 or 10mm); the guard shield material can be glass known in the art or metal rather than quartz, and this is because known glass and metal are to be better than quartzy He and H ₂Diffusion barrier.For example; with reference to figure 2; show lamp 44 with electric arc tube 46; electric arc tube 46 is contained in reflector 48 and the lens 50 and be reflected mirror 48 and lens 50 surround, and it is hermetic closed or be contained in it that speculum 48 and lens 50 form containment vessels and gas medium that will be identical with gas medium or gas 38 or gas 52.The interior gas medium 52 of containment vessel that electric arc tube 46 is closed in speculum 48 and lens 50 formation surrounds and cooling.Electric arc tube 46 comprise two ends by first column 56 and second column 58 to small part the printing opacity shell 54 on stifled.Electric arc tube 46 as known in the art also can be similar or identical with electric arc tube 12.By make substrate and/or face coat and/or applying coating (for example coating that the application mentioned) by metal or glass, preferably make speculum 48 and lens 50 anti-gas 52 divergence losses or 52 divergence losses of anti-gas.

The thermal conductivity of gas medium 38 and the pressure independent of gas are as long as gas medium is continuous state or fluid attitude rather than molecular state.The transformation of free molecular flow attitude to continuous state takes place when Knudsen number＜＜1.Knudsen number is the dimensionless fluid parameter, and its mean free path that equals gas collisions is divided by the typical space size in the gas cell-shell (being the gap 62 between the electric arc tube outside and the guard shield inboard in this case).Be Kn＜0.01 of He refrigerating gas in the guard shield of 1.0mm o'clock in the gap 62 that is separated by with the electric arc tube outside, the pressure of He must be greater than 200Torr.Thereby (1bar, dosage 760Torr) are enough to keep few to 30% of initial He amount so in the whole useful life of lamp if charge into about 1 atmospheric pressure at first in guard shield in system lamp process.Under the situation of the cooling effect that suitably weakens He, and/or under the situation of the gap between guard shield and the electric arc tube greater than 1.0mm, necessity reservation amount of He can be significantly less than 30% in the whole useful life of lamp.If in the whole useful life of lamp, there is sizable He loss, and if be that the N of certain percentage has been added in realization high-voltage breakdown insulation ₂, the He amount that must keep in the whole useful life of lamp so should be approximately greater than N ₂Initial percentage, to keep the important function of He to the cooling electric arc tube.

By using the refrigerating gas 38 of enclosing electric arc pipe, the T3 temperature in the electric arc tube preferably is lower than 1700,1600,1500,1475,1450,1425,1400,1375 or 1350K, so that the useful life of lamp is longer.

As exemplary embodiment, the present invention can realize in the described device of WO 2004/023517A1 (being hereby incorporated by).The N that has 1.5atm (25 ℃ time) in the WO 2004/023517A1 instruction guard shield ₂According to the result of 3 dimension finite element thermal models, if replace N with the He of 1.5atm (25 ℃ time) ₂, the guard shield wall of quartzy guard shield be that 2mm is thick and guard shield is inboard and the electric arc tube outside between the annular gap be under the situation of 0.5mm, with the described similar ceramic arc tube inner top central thermal zone temperature T 3 of WO 2004/023517A1 with decline 240K.He and N ₂The electric arc tube temperature that causes of the cooling effect size and the temperature that reduce with electric arc tube and guard shield change, but cooling effect is usually in about 100-350K scope.He is better than N ₂Hot advantage can be used for lamp behaviour other improve, for example reduce the size of electric arc tube and/or guard shield.For example, with reference to WO 2004/023517 A1, (the interior diameter ID=1.2mm if the size of electric arc tube remains unchanged, overall diameter OD=2mm) and the guard shield interior diameter keep ID=3mm, for realizing identical T3 temperature, can make guard shield overall diameter OD little when using He so, and use N to 5.2mm ₂The time can make the guard shield overall diameter little to 7mm.Less and thin guard shield makes aspect the optical property of lamp or can have remarkable advantages aspect the manufacturing process of lamp.Obviously the reducing of size also comes from electric arc tube 12 and the interior diameter ID of pipe 16 and reducing of overall diameter OD.For example, T3 temperature decline 240K allows electric arc tube overall diameter OD to be decreased to about 1.5mm from about 2.0mm, and the interior diameter of electric arc tube is also corresponding to be reduced.Because the reducing of interior diameter ID, under the situation of wall stable arc (be the arc gap〉〉 ID), arc diameter (arc diameter) reduces, and makes electric arc brightness become positive example with arc diameter usually.Usually, with refrigerating gas for example He replace N ₂Can make electric arc tube interior diameter ID reduce about 20-30%, thereby make brightness improve about 20-30%, for example auto bulb, projecting apparatus provide tangible performance advantage with the light source in lamp or the optical fiber etc. can to use (beam-forming application) thus to pack.In addition, by refrigerating gas the electric arc tube interior diameter ID that the cooling effect of electric arc tube realizes is reduced to make that the temperature difference between electric arc tube top and the bottom is less, this is because convection current and the ID of gases at high pressure in electric arc tube ^-3Being approximated to positive example obviously descends.Thereby for example electric arc tube interior diameter ID reduces about 25% and causes temperature difference to reduce about twice.Temperature difference reduce and the less pressure-driven circumference stress that causes of interior diameter ID (pressure-driven hoop stress) reduces to make the stress in the electric arc tube shell obviously to reduce, thereby provide possibility with the life-span for long lamp.In addition, refrigerating gas can make electric arc tube and/or arc gap shorten identical size to the cooling effect of electric arc tube, thus the brightness that has also improved light source.Refrigerating gas 38 for example He hot advantage also can with cooling advantage combination, described cooling advantage comes from the gap that reduces between the electric arc tube outside and the guard shield inboard, and increases the overall diameter (or ground of equal value increases the wall thickness of guard shield) of guard shield in addition.As described below, the advantage that two other advantage of the shielding structure of cooling electric arc tube and refrigerating gas produce is suitable.The hot path that is dissipated in the heat on the arctube walls has four fundamentals, comprises thermal conductivity, the thermal conductivity by gas medium 38, the thermal conductivity of passing through guard shield 14 walls and the last heat transmission to ambient air outside that realizes by convection current and radiation usually by electric arc tube 12 walls.Analysis (the thermal conductivity representative value that comprises electric arc tube 12, gas medium 38 and guard shield 14 to the heat transfer equation of cylindrical geometry body, and guard shield 14 inside are to the thermal transmission coefficient in the external world) show the heat transmission that the major limitation that whole heat is transmitted and finally cool off electric arc tube inside is the thermal resistance and the guard shield lateral ambient air outside of gas medium 38, however big unlike other two hot key elements by the thermal conductivity of electric arc tube 12 walls and guard shield 14 walls to the electric arc tube Temperature Influence.The first restriction element i.e. thickness in the gap 62 between the thermal resistance by gas medium 38 and the electric arc tube outside and the guard shield inboard is approximated to ratio, and with the thermal conductivity of gas medium be inverse relation.Thereby, if by replacing N with He gas ₂The thermal conductivity of gas medium is brought up to be about typical N ₂Four times of conductance heating rate value, the typical sizes for the discharge head lamp can be by being reduced to the suitable hot advantage of about 0.5mm acquisition with gap 62 from about 2mm so.In fact, thermal model confirms, by gap 62 is reduced to about 0.5mm from about 2mm, makes T3 descend 100-200 ℃ at least, thereby can realize cooling and/or less electric arc tube uniformly.System is difficult to during lamp gap 62 obviously is reduced to 0.5 or below the 0.25mm usually.Usually,, or be more preferably less than 0.25 times electric arc tube overall diameter, or most preferably less than 0.1 times electric arc tube overall diameter, then little gap 62 hot with the obvious advantage if the gap, is more preferably less than 0.5 times electric arc tube overall diameter less than the overall diameter of electric arc tube.In addition,, then can further strengthen cooling effect, thereby can realize cooling and/or less electric arc tube uniformly electric arc tube if can increase the heat transmission of guard shield lateral surrounding air.Usually proportional by the heat transmission from guard shield lateral surrounding air of convection current and radiation realization external surface area common and guard shield, if the geometry of guard shield is cylindrical or closely cylindrical, overall diameter OD common and guard shield is proportional for described external surface area.Thereby for example the overall diameter of guard shield increases about 20-50% or manyly can obviously reduce the temperature of electric arc tube and/or realize less electric arc tube.The interior diameter of supposing guard shield depends on the overall diameter of electric arc tube and the gap 62 between the electric arc tube outside and the guard shield inboard, and the external surface area that improves guard shield so requires thicker guard shield wall or guard shield to have texture or ripple outer surface.For example, be generally the discharge head lamp typical sizes of 1mm for the guard shield interior diameter for about 5-10mm and guard shield wall thickness, the guard shield wall thickness doubles as 2mm and the guard shield overall diameter will be increased and makes the about 40%-20% of heat transmission increase from the guard shield outer surface.The hot advantage of thicker guard shield constantly increases with the increase of guard shield wall thickness, reaches the thickness that is called critical radius up to the thickness of guard shield wall.For the discharge size of head lamp of the typical case with quartz or glass oversheath, critical radius is about 160mm.Although it is obviously very difficult above the lamp of about 1-3mm to make guard shield thickness, if quartz or glass shield can be made significantly thicker the thickness limit until about 160mm, then the hot advantage of cooling and/or small arc pipe will constantly be improved.In fact, as shown in Figure 3 and Figure 4,, then can obtain hot advantage to hot-zone (common on the electric arc between the electrode) in the electric arc tube if guard shield is a heavy wall along the electric arc tube zone of contiguous arc gap only.Along the guard shield wall can be obviously thinner in the shield region of electric arc tube column and in the sealing area beyond the electric arc tube column, make the guard shield wall that in the sealing area beyond the column, approaches to simplify the hermetic seal of guard shield.In addition, for the same reason, only needing in the zone of contiguous arc gap is little gap 62 between the electric arc tube outside and guard shield inboard.Guard shield makes that near electric arc tube the hottest part of electric arc tube is obviously cooled off in this zone in arc zone, and guard shield need not too near electric arc tube in colder usually column zone.This situation as shown in Figure 1.Usually, if the thickness of guard shield wall greater than 10% of guard shield interior diameter, more preferably greater than 20%, 30%, 50% or 75% of guard shield interior diameter, or more preferably greater than 100% of guard shield interior diameter, then thicker guard shield wall has tangible hot advantage.Capable of being combined by cold gas, gap 62 and the cooling of guard shield overall diameter generation and/or the advantage of small arc pipe, make the combination of any two kinds of advantages or the combination of whole three kinds of advantages act on independent advantage greater than any one.

The cooling effect of considering guard shield reduces and/or the increase of guard shield wall thickness and obviously strengthening with gap 62, thereby size that can be by changing gap 62 and/or design Temperature Distribution in the electric arc tube along the guard shield wall thickness of electric arc tube length range.Particularly, wish to reduce the temperature of the hot-zone (in horizontal ignition arc pipe, being usually located at above the electric arc middle part) of electric arc tube, improve in the electric arc tube temperature of cold-zone (liquid metals halide pond produces the position of the required high vapour pressure of photic gas in the electric arc tube, and this position is usually located in the electric arc tube below the electrode and/or the bottom corner of electrode back) simultaneously.Thereby, wish to reduce the electric arc top usually near the electric arc tube temperature in the zone at electric arc middle part, improve the electric arc below simultaneously and be arranged in below the electrode and the electric arc tube temperature in the zone of back.These temperature difference are owing to the cold-zone temperature may be crossed the low performance that is unfavorable for lamp, and the intensity that under the overheated situation in hot-zone, also is unfavorable for electric arc tube, temperature gradient itself also particularly produces stress in the ceramic arc tube at electric arc tube, may be because cracking or gas leakage cause electric arc tube to lose efficacy ahead of time.In horizontal ignition arc pipe, azimuth temperature gradient (promptly by the top to the bottom, particularly in the electric arc central region) and axial-temperature gradient (promptly from the electric arc middle part to post end, particularly in the zone near electrode) cause the stress that merits attention especially.Interior diameter ID by reducing electric arc tube (cooling effect by shielding structure (comprise refrigerating gas 38 and the gap 62 that reduces and the guard shield wall thickness that increases) realizes) or by gap 62 thickness between the design electric arc tube outside and the guard shield inboard and/or according to along electric arc tube axially and/or the thickness of azimuth position design guard shield wall, can realize by improving the performance that the cold-zone temperature improves electric arc tube with respect to the hot-zone, perhaps, perhaps prolong the life-span of lamp by the stress in the reduction electric arc tube by reducing the intensity that the hot-zone temperature improves electric arc tube.For example, in order to reduce the hot-zone temperature, as shown in Figure 3 and Figure 4, can make the guard shield wall thicker along the arc zone of electric arc tube, and/or electric arc tube can be installed in the position that the guard shield axis normal makes progress as shown in Figure 5, makes gap between the electric arc tube outside and the guard shield inboard little above the electric arc tube than below electric arc tube.By electric arc tube being installed in guard shield axis top, also will reduce the stress that the azimuth temperature gradient causes.

Fig. 3 shows the lamp that has guard shield 14b and have the electric arc tube 12b of printing opacity shell 16b.Guard shield 14b has reinforcement 70, and this reinforcement 70 has homogeneous thickness along the guard shield waist.As shown in the figure, reinforcement 70 is preferably than guard shield remainder or guard shield neighbouring part thick basically at least 10,20,25,30,40,50,70,90,100,120,150,200,250,300,400 or 500%.The position at contiguous electric arc tube middle part is extended or is positioned at reinforcement 70 preferred contiguous electric arc tube middle parts, mid point shown in preferably being centrally placed between the electrode tip, the part (the electric arc part of electric arc tube) between preferably contiguous whole discharge space 34b (spaces of shell 16b and two column 18b, 20b qualifications) extension or contiguous as shown in Figure 3 two electrode tips extend or contiguous (a) discharge space 34b or (b) space between two electrode tips or partly at least 10,20,30,40,50,60,70,80,90 or 95% extension of (the electric arc part of electric arc tube).Fig. 4 shows and the essentially identical lamp of lamp shown in Figure 3 that this light fixture has guard shield 14c and has the electric arc tube 12c of printing opacity shell 16c.Guard shield 14c has the reinforcement 70c of similar reinforcement 70, and different is that reinforcement 70c is in the guard shield outside rather than guard shield inboard.Perhaps, described reinforcement can partly be in the guard shield inboard and partly be in the guard shield outside.

As shown in Figure 5, the longitudinal axis of electric arc tube 12d can be positioned at or be fixed on guard shield 14d longitudinal axis the top (top be meant lamp between the operating period above), preferred at least 0.1,0.2,0.5,1,2,3,4,5,6,7,8,10,13,15,20,25,30,35,40,45,48% (comparing) more than the guard shield longitudinal axis with the guard shield interior diameter.Fig. 5 example is effectively constructed the azimuth temperature gradient of advantageously improving electric arc tube.

Fig. 6 shows the lamp that has guard shield 14e and have the electric arc tube 12e of printing opacity shell 16e.Fig. 6 and Fig. 3 are similar, and different is that this part 70e has narrower or less inner and outer diameter but thickness is constant by the reinforcement 70 among guard shield part 70e replacement Fig. 3.As the above-mentioned discussion to part 70, the position at contiguous electric arc tube middle part is extended or is positioned at the same preferred contiguous electric arc tube of this part 70e middle part.The interior diameter of part 70e is preferably little by at least 1 than the interior diameter of adjacent guard shield 14e part, 2,3,5,8,10,15,20,25,30,40,50,60,70 or 80%.A kind of gap 62 thickness that change of Fig. 6 example are advantageously to improve the method for axial-temperature gradient.

Fig. 7 shows the lamp that has guard shield 14f and have the electric arc tube 12f of printing opacity shell 16f.Electric conductor 24f and loop lead-in wire or down-lead bracket 30f are electrically connected, extend in electric arc tube position vertically upward in described loop lead-in wire or the gap of down-lead bracket 30f between electric arc tube 12f (and shell 16f) outer surface and guard shield 14f inner surface or are positioned at electric arc tube position (upwards be meant at lamp and make progress between the operating period) vertically upward.The part of insulating case 72 jacket down-lead bracket 30f is to prevent arc discharge.By this structure, can conduct and scatter and disappear by metal lead wire support 30f from the part heat of electric arc tube top (position that need cool off).62 regional intermediate gaps 62 and down-lead bracket 30f diameter ratio are more preferably less than 3:1,2:1 or 1.5:1 preferably less than 5:1 in the gap.

Shown in Fig. 9 a and 9b, in another kind of embodiment, can increase the guard shield wall thickness of electric arc tube top with respect to the guard shield wall thickness of electric arc tube below.With reference to figure 9a, show the lamp that has guard shield 14a and have the electric arc tube 12a of printing opacity shell 16a.Fig. 9 b shows the lamp that similarly has guard shield 14v and have the electric arc tube 12b of printing opacity shell 16b.As shown in the figure, guard shield 14a and 14b have reinforcement 68,69 respectively, and described reinforcement is preferably basically than guard shield remainder or adjacent guard shield part thick at least 10,20,25,30,40,50,70,90,100,120,150,200,250,300,400 or 500%.Reinforcement 68,79 can similar Fig. 3 and the reinforcement of Fig. 4 extend axially, and part 68,69 is for the top of guard shield or top and can be top 180 degree, 150 degree, 120 degree, 90 degree, 60 degree or other angles (seeing Figure 10 and 12), and reinforcement 68,69 can have homogeneous thickness (seeing Figure 10 and 12), or can convergent, the thickening (seeing Figure 11) during near the top with convenient wall.The shielding structure purpose of Fig. 9 a and 9b is to reduce the hoop temperature gradient.Compare with the guard shield wall thickness of electric arc tube bottom center portion, above electric arc tube, thicker guard shield 14a, the 14b of wall causes the inhomogeneous cooling of electric arc tube above particularly in the middle part of the electric arc tube directly over electric arc or the discharge space, comparing to the top with the bottom provides more cooling, thus the stress that has obviously reduced the hoop temperature gradient in the electric arc tube and caused.(in aforementioned discussion, the top of electric arc tube is meant the top of electric arc tube in the use, this be because heat rises and for various reasons the electric arc tube top in the use be tending towards than the bottom of the electric arc tube in use heat.) uneven guard shield wall thickness also can be in conjunction with resembling the advantage of electric arc tube being installed Fig. 5, promptly, make electric arc tube longitudinal axis vertical off setting and vertically be higher than the guard shield longitudinal axis or be arranged in guard shield longitudinal axis top (use) (shown in Fig. 9 b), thereby have the effect that reduces vertical and hoop temperature gradient in the electric arc tube and the effect of the stress that reduces to be caused.As shown in Figure 6, in another kind of embodiment, the gap 62 between the electric arc tube outside and the guard shield inboard can change vertically with the axial variation of electric arc tube overall diameter and/or guard shield interior diameter.Gap 62 is more little, and guard shield is big more to the cooling effect of electric arc tube local temperature, makes diameter advantageously reduce the hot-zone temperature of electric arc tube with respect to the cold-zone of electric arc tube near near the guard shield little arc zone than the electric arc tube electrode zone.Thereby in use electric arc tube has axial-temperature gradient.For example, can effectively reduce the mode at hot-zone temperature (for example above electric arc tube arc chamber or electric arc shell middle part), thereby, (a) change guard shield wall thickness or (b) change the thickness in gap between electric arc shell and the guard shield or (c) change both simultaneously advantageously to improve the mode of axial-temperature gradient.Similarly, if the electric arc tube diameter is big and less near electrode near the electric arc, and the guard shield interior diameter be constant in above-mentioned zone, and guard shield also will advantageously reduce the hot-zone temperature with respect to the cold-zone near outside the electric arc tube near electric arc so.For example under the situation of nearly ellipsoid (being the prolate spheroid) shape electric arc tube and cylindric guard shield, can realize this situation.Nearly elliposoidal electric arc tube can be designed to have better isothermal usually and distribute in electric arc and electrode zone, in conjunction with the cylindric guard shield with constant inner diameter, the ellipsoid electric arc tube will plant work at better isothermal branch.In addition, the cooling effect of guard shield big more (be that gap 62 is more little, and/or the guard shield wall is thick more, and/or refrigerating gas He for example) waits temp effect good more in conjunction with the cylindric guard shield of ellipsoid electric arc tube.

Although describe the present invention with reference to preferred embodiment, one skilled in the art will appreciate that without departing from the present invention, can make various variations and can replace key element of the present invention by equivalent feature.In addition, under the situation that does not break away from essential scope of the present invention, can make various changes so that concrete condition or material adapt to instruction of the present invention.Thereby, the invention is not restricted to expect the specific embodiments of conduct enforcement best mode of the present invention fall into all interior embodiments of claims scope but the present invention includes.

Claims (22)

1. a lamp comprises the electric arc tube with printing opacity shell and a pair of spaced electrode, and the gas medium that described electric arc tube is closed in its outside containment vessel surrounds, in the time of 25 ℃ at least the described gas medium of 10mol% by He or H ₂Or when Ne or 800 ℃ thermal conductivity greater than N ₂Other gas or their mixture provide.

2. the lamp of claim 1, wherein 25 ℃ the time at least the described gas medium of 80mol% provide by He.

3. the lamp of claim 1, wherein the pressure of described gas medium is 0.1-10atm 25 ℃ the time.

4. the lamp of claim 1, wherein the 0.1-90mol% of described gas medium is N 25 ℃ the time ₂

5. the lamp of claim 1, wherein said containment vessel is a guard shield, described guard shield has inner surface and interior diameter and outer surface and overall diameter.

6. the lamp of claim 5, the coated abundant covering of the inner surface of wherein said guard shield or outer surface, described coating is effective as the diffusion impervious layer that suppresses described gas medium divergence loss.

7. the lamp of claim 6, wherein said coating comprises tantalum oxide or titanium dioxide or aluminium oxide or hafnium oxide or other high temperature transparent material or their combination.

8. the lamp of claim 5, wherein said printing opacity shell has overall diameter, and the difference between the overall diameter of described printing opacity shell and the interior diameter of described guard shield is less than the twice of described printing opacity shell overall diameter.

9. the lamp of claim 5, the difference between the overall diameter of wherein said guard shield and the interior diameter of described guard shield is greater than 20% of described guard shield interior diameter.

10. the lamp of claim 1, wherein said printing opacity shell is the pipe of overall diameter less than 4mm.

11. the lamp of claim 5, the overall diameter of wherein said guard shield is less than 8mm.

12. lamp; comprise electric arc tube with printing opacity shell and a pair of spaced electrode; the gas medium that described electric arc tube is closed in its outside containment vessel surrounds; described printing opacity shell has outer surface and overall diameter; described containment vessel is the guard shield with inner surface and interior diameter; have the gap between the outer surface of described printing opacity shell and the inner surface of described guard shield, described gap is less than the overall diameter of described printing opacity shell.

13. the lamp of claim 12, wherein said gap is less than half of described printing opacity shell overall diameter.

14. lamp; comprise electric arc tube with printing opacity shell and a pair of spaced electrode; the gas medium that described electric arc tube is closed in its outside containment vessel surrounds; described printing opacity shell has outer surface and overall diameter; described containment vessel is the guard shield with inner surface and interior diameter and outer surface and overall diameter; described guard shield has wall thickness between described outer surface and inner surface, the described wall thickness of described guard shield is greater than 10% of described guard shield interior diameter.

15. the lamp of claim 9, the difference between the overall diameter of wherein said guard shield and the interior diameter of described guard shield is greater than 100% of described guard shield interior diameter.

16. the lamp of claim 8, the difference between the overall diameter of wherein said guard shield and the interior diameter of described guard shield is greater than 20% of described guard shield interior diameter.

17. lamp, comprise electric arc tube with printing opacity shell and a pair of spaced electrode, the gas medium that described electric arc tube is closed in its outside guard shield surrounds, described electric arc tube has the electric arc part, and the wall thickness of the guard shield first of contiguous electric arc part is greater than the wall thickness of the guard shield second portion of being separated by with described first.

18. lamp, comprise electric arc tube with printing opacity shell and a pair of spaced electrode, the gas medium that described electric arc tube is closed in its outside guard shield surrounds, described electric arc tube has axial-temperature gradient in the course of the work, described guard shield has wall thickness, described electric arc tube has outer surface, described guard shield has inner surface, have the gap between the outer surface of described electric arc tube and the inner surface of described guard shield, wherein the wall thickness of (a) guard shield or (b) gap thickness or (c) thickness in the wall thickness of guard shield and gap to change to advantageously improving described axial-temperature gradient effective and efficient manner.

19. lamp, comprise electric arc tube with printing opacity shell and a pair of spaced electrode, the gas medium that described electric arc tube is closed in its outside guard shield surrounds, described guard shield has longitudinal axis, described electric arc tube has longitudinal axis, and described electric arc tube longitudinal axis is with to advantageously improving the described guard shield longitudinal axis of azimuth temperature gradient effective and efficient manner vertical off setting of described electric arc tube.

20. the lamp of claim 5, wherein said printing opacity shell has outer surface, and described lamp comprises the down-lead bracket that is electrically connected with one of described electrode, and described down-lead bracket extends between the outer surface of the inner surface of described guard shield and described printing opacity shell.

21. the lamp of claim 17, wherein the wall thickness of the guard shield part of electric arc part top is greater than the wall thickness of the guard shield part of electric arc part below.

22. the lamp of claim 12, wherein said guard shield has longitudinal axis, and described electric arc tube has longitudinal axis, the described guard shield longitudinal axis of described electric arc tube longitudinal axis vertical off setting.

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