I||||||||||||||||||||||||||||||||l||1|||||l|l||||||||||||||||||||||||||||||
`
`USOU7679276B2
`
`(12) Ulllted States Patent
`Blondia et al.
`
`(10) Patent No.:
`(45; Date of Patent:
`
`US 7,679,276 B2
`Mar. 16, 2010
`
`(54) NIETAL BODYARC LAMP
`
`(75)
`
`Inventors: Rudi Blondia. l“rt:monl, (IA (US): John
`Kiss, San Jose. (‘A (US): Douglas A.
`D0ughty‘Gi1my.(.A(US)
`
`(73) Assignec: Perkinelmer Singapore Pte Ltd..
`Singapore (SG)
`
`( * } Notice:
`
`Subject to any disclainlcr, lht: tcrn1 oflhis
`patient
`is extended or adjusted under 35
`U.S.C. 154-(b) by 838 days.
`
`(21) App1.No.: ll!291,295
`
`(22)
`
`Filed:
`
`Dec. 1, 2005
`
`(65)
`
`Prior Publication Data
`
`US 2006r'Ol 75947 Al
`
`Aug. 10, 2006
`
`5.418.420 A
`5,5(1,338 A
`5‘6—;2.931 A
`5.121.465 A
`5.961.203 A
`
`5.51995 Rubens
`3135114
`1051996 R be .
`I.
`313.546
`9l,l997 K?“ igafll 3l3_l,.44
`l_
`‘
`‘
`_,
`2.098 Roberts
`313.-46
`1031999 Schuda ..................... .. 35215294
`
`5-034-457 A
`6.114.807 A
`6.179.446 Bl
`
`3-"2900 Rflbcfls
`952000 Kavanagh
`152001 Sarmadi
`
`3|-T45
`3I3-‘S70
`362.-"364
`
`(Co11tinued)
`
`FOREIGN PA'I'l3NT DOCUMENTS
`
`GB
`
`2 2913 132 A
`
`12-"1995
`
`Related U.S. Application Data
`
`lcumimmdi
`
`(60)
`
`Provisionzil application No. 6016.34.56] . filed on me.
`9? 2()[}4_
`
`-"’P’5"*‘fi'*'_l’ =’r3-wrv=r'r=er- -Viv Patel
`(74) Atrormsy. Agem, or Firm—M0rriso11 8:: Foerster LLP
`
`(2005.01)
`
`(51)
`
`(56)
`
`[nt_ (_‘1_
`IIMJ I/38
`3l3!252; 3131243
`(52) U.S. Cl.
`(58) Field of(?lassification Search ................. .. 313140.
`313144. 45, 113. 243, 252
`See ztppliczttion file for cornplctt: search l1is1o1'y.
`Refemmes Cited
`U,s, PATENT DOCUMENTS
`
`(57)
`
`ABS'l”RAC'l'
`
`A 51101" W9 lam]? C‘~‘mPl'i5*35 lmnl and back 5“b*'-'55‘-"'“hll*’5
`including mating weld rings. whereby the lamp can be
`assembled and scaled through welding of the weld rings.
`Each subassenibly includes a number oi selI—al1gmng com-
`ponents to facilitate assembly and iniprove alignnient accu-
`racy. The metal body of the lamp can have 2| cooling projec-
`tion portion. which can be receiveci by a heat sink to ren1ovt-.-
`heat from near the anode. A heat sinl< also can be fornied
`part ofthe metal body. The lamp rellector can be 21 drop-in
`reflector. or can he lornied as part oflhc metal body llirough
`:1 process so-::l1 as metal injcctiori rr1(1ldi11g.A single strut can
`housed to Ilt)si1ioi11l1t:ca1l1odC, which ca11lJCPar‘tofLhcslt:evc
`or received by {I portion ofthe sleeve. A trigger electrode can
`-
`-~
`,
`-
`be used to sinipltty the power supply lor the lamp.
`
`9 Claims, 22 Drawing Sheets
`
`500
`KM
`
`1
`1
`
`ASML 1117
`
`ASML 1117
`
`""""
`
`
`4,-1974 MGR“ e, a|_
`‘M1935 Robefls
`12.-' 1986 Roberts et al.
`4-"1937 R°be”S
`10.-‘I987 Rubens ...........
`[H1988 Robcns et al.
`4.51989 Roberts et al_
`7.-1990 Schtlda el :11.
`3.-‘I995 Roberts
`
`3 13,1 13
`313.-"510
`313-'1 13
`-- 313-713
`445526
`313.-"'32
`3l3:_23] .61
`. 315-"24-6
`3|}.-"'46
`
`
`
`iv
`
`A
`
`3.g03_495
`4.599540
`4.633.128
`4:653-[79
`4.702.716
`4.785.216
`4.823.043
`4.940.922
`5.399.931
`
`>I'2I>>I£=-11'-I>>>>
`
`
`

`
`US 7,679,276 B2
`Page 2
`
`313346
`362.1263
`313,.-[[3
`352.-253
`3[3_.-[[3
`
`6.-'20G2 Manning el :11.
`532003 Kavanagh
`';,-2003 R0139,-l3,31a[_ __
`5.-2003 Kavanagh
`1032003 Manning
`
`
`
`6,400,067 B1
`6.561.675 B1
`5_59j.r‘gg7 B2
`20030090902 Al
`2003..-'0[93331 A1
`
`{-‘()R1:_7,](}N pA‘1‘1'_.;N'1‘1)()(f1JM]3N’]‘3
`
`RU
`W0
`W0
`
`519792
`W0 93-“Z6034
`W0 93131043
`
`7.-“I976
`1211993
`751993
`
`* cited by examiner
`
`US, PATENT DOCUMENTS
`
`1.1200] Roberts ..................... .. 313.146
`
`-- 315-935
`1-9001 Greenland
`31200] Rubens elal.
`3623263
`8.12001 Capobianco
`3133113
`9:200] Kissetal.
`313.-‘"634
`10.-‘"2001 Roberls
`313,631
`11.62001 Roberlselal.
`313.-113
`1]e’200l Kaas
`31556
`1.12002 Miyamolo eta].
`3139113
`212002 Roberts
`3133113
`«H2002 R(3!]1£i.l'Il:'(llk el al.
`3l5I85
`
`
`
`6.181.053 B1
`6-131-077 B1
`6,200,005 Bl
`6,274,970 131
`6.285.131 Bl‘
`6,297,591 B1
`6,316,867 B1
`6316.87? Bl
`6.339.279 B1
`6.351358 131
`6.376.993 Bl
`
`2
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet] of 22
`
`US 7,679,276 B2
`
`.5.25._.9".
`
`3
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 2 of 22
`
`US 7,679,276 B2
`
`300
`
`302
`
`4
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 3 of 22
`
`US 7,679,276 B2
`
`310
`
`300
`
`5
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 4 0f22
`
`US 7,679,276 B2
`
`400
`
`6
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 5 M22
`
`US 7,679,276 B2
`
`420
`
`7
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 6 of 22
`
`US 7,679,276 B2
`
`430
`
`310
`
`\\\\\_\II
`
`8
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 7 0f22
`
`US 7,679,276 B2
`
`500
`
`506
`
`9
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 8 of 22
`
`10
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 9 M22
`
`US 7,679,276 B2
`
`11
`11
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 10 of 22
`
`US 7,679,276 B2
`
`604
`
`600
`
`614
`
`Fig. 6(3)
`
`12
`12
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 11 of 22
`
`US 7,679,276 B2
`
`500
`
`614
`
`
`
`
`
`602
`
`
`
` L\Vn\\&\\V[‘ Tllllfi
`
`
`@h‘
`
`
`
`618
`
`612
`
`13
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 12 of 22
`
`US 7,679,276 B2
`
`700
`
`704
`
`714
`
`Fig. 7(a)
`
`14
`14
`
`

`
`U.S. Patent
`
`Mar. 16, 2010
`
`Sheet 13 of 22
`
`US 7,679,276 B2
`
`702
`
`15
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 14 of 22
`
`US 7,679,276 B2
`
`800
`
`16
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 15 of 22
`
`US 7,679,276 B2
`
`900
`
`Fig. 9
`
`17
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 16 of 22
`
`US 7,679,276 B2
`
`18
`
`

`
`Mar. 16, 2010
`
`Sheet 17 of22
`
`19
`
`

`
`2020
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 19 of 22
`
`US 7,679,276 B2
`
`1200
`M
`
`21
`21
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 20 of 22
`
`US 7,679,276 B2
`
`22
`22
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 21 of 22
`
`US 7,679,276 B2
`
`1300
`
`1322
`
`Fig. 13(b)
`
`23
`23
`
`

`
`U.S. Patent
`
`Mar. 16,2010
`
`Sheet 22 of 22
`
`US 7,679,276 B2
`
`Intensity Sensor
`
`L
`
`¢—-J
`
`Control Unit
`
`
`
`Power Supply
`
`1408
`
`1410
`
`1402
`
`Cooling Device
`
`1414
`
`Processor
`
`Signal Amplifier
`
`Temperature
`Sensor
`
`24
`24
`
`

`
`1
`METAL BODY ARC LAMP
`
`CLAIM OF PRIORITY
`
`US ?,6'i’9,276 B2
`
`2
`
`This application claims priority to US. Provisional Patent
`Application No. 6l)i’634.5(il, filed Dec. 9. 2004. which is
`hereby incorporated herein by reference.
`
`TECHNICAL FIELD OF THE INVENTION
`
`The present invention relates generally to light sources and
`particularly to are lamps and methods ofmanufactttring such
`lamps.
`
`BACKGROUND
`
`Short arc lat11ps provide intense point sources of light for
`applications such as medical endoscopes. instrumentation.
`and video projection. Short arc lamps also are used in indus-
`trial endoscopes, such as in the inspection ofjet engine inte-
`riors. More recent applications have included dental curing
`systems. as well as color television receiver and movie theater
`projection systems. such as is described in pending US.
`Provisional Patent Application No. 60t'634.'r'29_. entitled
`“SI-IORT ARC LAMP I_.lGI IT ENGINE FOR VIDEO PRO-
`JECTION," filed Dec. 9. 2004. hereby incorporated herein by
`reference. A typical short are lamp comprises an anode and a
`sharp-tipped cathode positioned along the longitudinal axis
`of a cylindrical, sealed concave chamber in a ceramic reflec-
`tor body that contains xenon gas pressurized to several atmo-
`spheres. Descriptions of such are lamps can be found. for
`example. in US. Pat. Nos. 5.721.465. 6.181.053. and 6,3l6,
`867. each of which is hereby incorporated herein by refer-
`ence. The manufacture of high power xenon arc lamps
`involves the use ofexpensive and exotic materials. as well as
`sophisticated fabrication. welding. and brazing procedures.
`Reduction in parts cotutt. assembly steps and tooling require-
`ments provides cost savings and improved product reliability
`and quality.
`Exemplary prior art are lamps are shown in FIGS. 1 and 2.
`The first lamp 100 comprises an optical coating 102 on a
`sapphire window 104. a window shell flange 106. a body
`sleeve 108. a pair of tlanges I10 and 112. a three piece strut
`support assembly 114. a cathode 116. an alumina-ceramic
`elliptical reliector body 118. a metal shell or sleeve 120. a
`copper anode base 122. a base weld ring 124. a tungsten
`anode 126. a gas tabulation .128. and a charge of xenon gas
`130. The second lamp 200 comprises a tilted hot mirror
`assembly 201 including. a retaining ring 202, a tilted collar
`204, a color filter 206. a hot-mirror 208, and a ring housing
`21 0. A tilted land 212 inside the ring housing 21 I} matches the
`orientation of the tilted collar 204. The lamp further includes
`a sapphire window 214 set in a ring frame 216. A single bar
`strut 218 attaches at opposite points on the bottom of the ring
`frame 216. A cathode 220 has a slotted end opposite to the
`pointed arodischarge end. A body sleeve 222 has a xenon—fill
`tttbulation 224 made of copper tubing. A xenon gas charge
`226 is injected into the lamp 200 after final assembly. The
`lamp also includes a ceramic rellector 228. an anode flange
`230. and a tungsten anode 232.
`Problems with are lamps such as these include the rela-
`tively large number ofparts needed to manufacture the lamps.
`which increases manufacture time and cost. Also, it can be
`difiicult to achieve the precision aligmnent needed for the arc
`gap dimensions to assure consistent lamp operation in these
`are lamps. Additional tooling typically is used for alignment.
`
`which increases the time necessary for manufacture and
`increases the probability of damaging a lamp during manu-
`facture.
`
`Various attempts have been made to reduce the number of
`parts and improve the lifetimes and efliciencies of these
`lamps. Attempts were made to reduce the number of welds.
`such as by brazing pieces together. but the materials and
`brazing techniques available often did not provide the neces-
`sary strength for pressurized operation. The types ofmaterials
`being used and processes for manufacturing components
`were varied. but often resulted in designs that could not meet
`the cost target of the intended applications. due to the high
`costs ofmaterials such as ceramics. l’ urther, components such
`as a heat conductive mounting that were fabricated from a
`ceramic material to facilitate high temperature operation had
`poor heat conduction properties and did not facilitate heat
`transfer from the enclosed atmosphere. This limit on the
`operating temperature placed a constraint on the power at
`which the lamps could be operated.
`There also were many attempts to redesign the reflector in
`order to keep the reflector cool. A conventional reflector is
`electroformed. with a heat conductive mounting that is built
`up by electroplating. then machined to the proper size. Alter-
`natively. the reflector can be brazed to a metal heat conductive
`mounting then machined. These steps require a significant
`amount of additional machitting and cost. Another approach
`was to machine the reflector directly irtto the heat conductive
`mounting. using a machine such as a precision diamond tool
`lathe. The reflector then is coated with a material such as
`
`silver. This still required a significant amount of machining,
`and the lathe-produced reflector typically had grooves or
`surface roughness that did not produce an optical reflector.
`Due to the increasingly large numbers of xenon are lamps
`being produced and marketed. opportunities to save money
`on the materials. manufacturing, ar1d.«’or assembly procedures
`are constantly being sought. Being the low—cost producer in a
`market typically translates into a strategic competitive advan-
`tage.
`
`BRIEF DIi'.SCRIP'I'ION OF THE DRAWINGS
`
`FIG, 1 is a diagram ofa first short are lamp assembly ofthe
`prior art.
`FIG. 2 is a diagram of a second short arc lamp assembly of
`the prior art.
`FIG. 3 is (a) a perspective view diagram and (b) a cross-
`section diagram of a back assembly of an arc lamp in accor-
`dance wilh one embodiment of the present invention.
`FIG. 4(a) is a diagram ofa back assembly having a drop-in
`reflector in accordance with one embodiment of the present
`invention.
`
`FIG. 4(b) is a diagram of another back assembly with
`grooved sides that can be used in accordance with one
`embodiment of the present invention.
`FIG. 4(c) is a cross-section ofa back assembly with a flat
`back.
`in accordance with one embodiment of the present
`invention.
`
`1U
`
`3U
`
`4U
`
`45
`
`50
`
`55
`
`60
`
`FIGS. 5(a)-5(f] show difT:rent views of back assemblies
`having an integrated heat sink in accordance with one
`embodintent of the present invention.
`FIG. 6(a) is an exploded view diagram ofa front assembly
`of an arc lamp in accordance with one embodiment of the
`present invention.
`FIG. 6(b) is a cross—section diagram of a front assembly of
`an arc lamp ir1 accordance with one embodiment of the
`present invention.
`25
`25
`
`65
`
`

`
`3
`
`4
`
`US ?,6'i’9,276 B2
`
`FIG. '7 is (a) an exploded view diagram artd (b) a cross-
`section diagram of another front assembly of an arc lamp itt
`accordance witlt one embodiment of the present invention.
`FIG. 8 is a diagrattt ofa sleeve having a single strut slot irt
`accordance with one embodiment of the present invention.
`FIG. 9 is a diagrant of a single strut piece in accordance
`with one embodiment of the present invention.
`FIG. 10 is a diagram of another sleeve in accordance with
`one embodiment of the present invention.
`FIGS. 1l(a}-(b) are diagrams of strut ring assemblies that
`can mate with the sleeve ofFIG. 10.
`
`FIG. 12 is a diagram of a sleeve with an integrated strut in
`accordance with one embodintent of the present invention.
`FIG. 13{a) is a cross—seetion diagram showing assembled
`front and back assemblies in accordance witlt one embodi-
`rttent of the present invention.
`FIG. 13(5) is a cross-section diagram showing assembled
`front and back assemblies including from artd rear heat sinks
`in accordance with one embodiment ofthc present invention.
`FIG. 14 is a schetnatic diagram which illustrates art
`approach wlterein the temperature of the lantp can be moni-
`tored and controlled based itt part on operating voltage.
`
`lJl_7.TAll..l'-El) DEESC RIPTION
`
`Systems and methods in accordance with various embodi-
`ments of tlte present invention can overcome these and other
`deficiencies in existing short are lamp assemblies. Arc larttps
`itt accordance with these embodiments can have fewer parts,
`use less expensive materials. utilize simpler tooling. and
`require fewer assembly steps tltan existing short are lamps.
`These are lantps can provide for a better yield. with lower
`labor costs and optimized automation.
`For discussion purposes. are lamps in accordance with
`various embodiments of the present invention can be divided
`into a pair of sub~assemblies. which will be referred to herein
`as a “l’ront“ assembly and 3 “back" assembly. These lamps
`then cart be constructed byjoining the front and back assem-
`blies. In one such are lantp. an arc is struck between an anode
`oftlte back assembly and a cathode ofthe front assembly in an
`enclosed atmosphere. typically containing xenon
`In
`other embodiments. the anode can be placed in the front
`assembly and the cathode irt the back assembly. It should be
`understood when the electrodes are discussed herein that the
`anode and cathode electrodes could be reversed in different
`
`embodiments. attd that the descriptions given are only meant
`to be exemplary. Ways of configuring electrodes in order to
`determine the flow of electrons across the arc gap are well
`known in the art artd will not be discussed in detail herein. The
`
`latttp includes a window or other transmissive element for
`emitting the light generated therein. and typically uses a
`reflector opposite the window for retlecting light‘ toward the
`window. A DC power supply can be used to apply a voltage
`across the gap between the anode and cathode as known iii the
`art.
`
`Art exemplary back assembly 300 is shown in FIGS. 3(a)
`attd 3(5). The back assembly has a base 304 that can be made
`of an appropriate metal, sttch as copper or a copper alloy.
`which cart be easier to shape and machine thana cerarttic. and
`can allow the lamp to run at :3 lower temperature by imp roving
`heat transfer and removal. This lower operating temperature
`can prolong the lifetime of the lamp. The metal body can be
`made using any appropriate fabrication method. such as by
`machining or milling the body front a metal cylirtder or block.
`The metal body 304 catt have a reflector cavity 306 fornted irt
`a first ertd. The cavity cart ltave a shape similar to that of the
`desired reflector, such as a spherical, parabolic, or elliptical
`
`shape. The surface finish of tire cavity cart be determined in
`part by the reflector to be used. For example. the cavity 306
`can be formed with a sufficient finish that the metal cavity acts
`as the reflector. wherein the metal reflector cavity also can be
`coated with an appropriate reflecting material. An advantage
`of a metal rellcctor over a cerantic reflector is that the metal
`does not have to be glazed before being coated. Appropriate
`coating materials capable ofwithstandittg the heat at which
`the arc lantp operates are known in the art. and cart include
`reflecting materials such as silver attd dichroic materials.
`including thin layers of metallic oxides. such as titanium
`oxide and silicon oxide. A dichroic coating can improve the
`performance it fthe reflector by absorbing unwanted or unmi-
`lized radiation. such as radiation irt the infrared andfor ultra-
`
`violet bands. whereby the reflected ligltt does rtot contain as
`much heat. In order to obtain the appropriate surface finish.
`the cavity 306 of the metal body 304 can be diamond turned.
`[it another approach, the metal body can be fornted by a MIM
`(metal injection molding) process using a fine particle size
`that does not require subsequent machining. Metal injection
`molding typically utilizes metal particles mixed into a birtder.
`This mixture then can be forced into a mold having the
`approximate dimensions of the desired part. The molded
`material then can be removed front the mold, and can be fired
`at high temperature irt order to sirtter the metal particles
`together and remove arty residual binder material. This pro-
`cess allows for the economical incorporation of complex
`features in a part. as separate macltining steps are not required
`to fonn these features.
`The metal body 304 can have a projection portion 316, or
`cooling cylinder, at an end opposite the first end. The cooling
`cylinder in one embodiment has a length of abottt 035 inches
`and a diameter of about 0.5 inches. the diameter being about
`twice the diameter of the anode 302. The diameter of the
`cooling cylinder cart be at least 33% of the diameter of the
`metal body. but less than the diameter ofthe metal body. such
`as a diartteterthat is less than 679% ofthe diameter oftlte metal
`body. The cooling cylinder 316 cart include a blind hole 308
`for receiving the anode 302. The blind hole can serve as a stop
`and allow for an easy but precise placement‘ of the anode
`relative to a central axis of the reflector 306. and can help to
`position the anode at a proper depth relative to the position of
`the cathode upon assembly. This cart help to minimize the
`amount of tooling needed to seat the anode. For example. in
`one embodiment the blind hole has a depth of 0.3 inches.
`which allows a 0. 75-inch long anode to extend approximately
`0.45 inches into the gaseous atmosphere. In this example.
`approximately 40% of the anode is in contact with the blind
`ltole for heat transfer. and about 60% ofthe anode is exposed
`to the plasma in the arc lamp. The amount of anode Contact
`with the blind ltole in this embodiment cart ltelp to ensure that
`electromagnetic interference generated by the lamp is not
`present at nominal operating powers. The use ofa blind ltolc
`instead ofa through hole eliminates an evacuation path from
`the gas interior to the outside environment. such that it is not
`necessary to seal the hole. The cooling cylinder 316 can have
`a smaller diameter than the bulk of the metal body 304,
`allowing a heat sink (not shown) to be attached directly to the
`rttetal body near the anode 302. The diameter of the cooling
`cylinder 316 can be larger than projecting features found in
`existing lamps. in order to provide a surface area capable of
`sulftciently conducting heat away front the lamp. The projec-
`tion also can lessen the distance between the exterior of the
`
`1U
`
`3o
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`metal body 304 artd the anode 302. which improves the
`removal of lteat front the anode. This can be important. as
`most of the heat generated by the arc can be conducted away
`by the anode during operation.
`26
`26
`
`

`
`5
`
`6
`
`US ?,6'i’9,276 B2
`
`Due to the high operating temperatures. tungsten often is
`ttsed for the anode and cathode electrodes. Tungsten can still
`erode at high power operation. however. and does not provide
`the amount of thermal conductivity ofother materials such as
`copper. As such. it can be desirable to utilize electrodes that
`are not made of a single material, but might have regions of
`diflerent materials. In one embodiment, a tungsten pill is used
`in a copper anode. The copper provides beneficial thennal
`conduction for cooling. and the tungsten provides the desired
`heat resistance. It can be desirable to form the blind hole 308
`
`5
`
`1D
`
`tor to be selllaligniitg, and maintains the precise position of
`the reflector relative to the anode and cathode. The alignment
`can be important. as a slight misaligmnent of the reflector of
`even 5;’: 0.00:)" can cause overheating dtte to a reduced amount
`of heat transfer. In one embodiment. the drop-in reflector has
`approximate dimensions of 1.2 inches in diameter (tapering
`to 0.6 inches in diameter) and 0,7 inches in length, with a
`circumferential ridge on the large diameter and a central
`aperture ofapproximately 0.3 inches in diameter. The cavity
`of the metal body can be fonned to l1ave substantially no
`spacing between the cavity and the drop-in reflector 414. in
`order to provide good thermal contact. An advantage to such
`a configuration is that the rellector does not need to be brazed
`into the metal body, but can be held in place by the self-
`aligning features and the front assembly as described below.
`In some embodiments utilizing a drop in reflector, the reflec-
`tor can be brazed to the metal body to allow for better thermal
`contact, as well as to allow for inverted handling of the sub-
`assembly. In one embodiment. the weld ring 410 has an inner
`lip feature (not shown) that can hold the reflector 414 against
`the metal body when the weld ring is brazed in place.
`The metal body component of the back subassemblies.
`such as component 304 in 1-’1G. 3 and component" 404 in I-‘IG.
`4(a), can have additional features incorporated to improve
`manufacturability andtor performance. FIG. 4(5) shows an
`altemate embodiment of such a metal body cotuponcnt 420.
`wherein grooves 422 are added to the exterior ofthe metal
`body. The inclusion of these grooves can reduce the overall
`weight of the component. as well as the amount of material
`required when manufactured using a MIM process, such that
`the cost of the component can be reduced. The grooves 422
`also function to increase the surface area of the component
`420, thereby improving the dissipation of heat generated by
`the are.
`In either ofthe embodiments shown in FIGS. 3{a)—(b) and
`4(a)—(b}. the cooling cylinder ofthe metal body can be shaped
`to receive a heat sink for removing heat from the lamp assem-
`bly. While short are lamps can be designed to operate at high
`power. sufficient heat removal can be needed to compensate
`for the increased power level operation. An arc lamp operat-
`ing with a xenon atmosphere can reach temperatures on the
`order of 200° Celsius. such that a sufilcient amount of heat
`must be removed to prevent premature erosion of the elec-
`trodes andfor failure of the braze seals. Ifa heat sink is not
`used. or if the lamp is to be brought into contact with a
`separate heat sink ofntechanism for heat removal. the cooling
`cylinder may not exist or can be of approximately the same
`dimension as the metal body. such as is shown in the embodi-
`n1ent of FIG. 4(c]. In this ernbodiment the back of the metal
`body 430 can be substantially fiat. with an exemplary body
`having dimensions of about 1.6 inches in diameter. This
`design allows the heat sink to be part of the device into which
`the lamp is placed, such as a projector, and would not require
`a heat sink to be attached to the lamp itself. This approach
`allows for easier replacement of the lamp and lowers the cost
`ofeach lamp. In addition. a standard heat sink can be attached
`to this cylindrical body. In this case the diameter ofthe hole in
`the heat sink can be designed to accept the full diameter ofthe
`body 430. rather then the smaller diameter of the cooling
`cylinder 316.
`FIGS. 5(a)-(e) show differing views ofa back assembly
`500 in accordance with another embodiment. wherein a heat
`sink 504 is integrated with the metal body 502. This configu-
`ration eliminates the thermal barrier that exists at the interface
`
`of a diameter that is large enough to allow the anode 302 to
`easily be positioned into the blind hole. but small enough that
`heat can be transferred from the anode irlto the sides of the
`blind hole 308. The anode can be brazed into the blind hole
`
`with the braze material filli11g the voids between the body and
`tl1c electrode, thus ensuring, adequate thermal contact ther-
`ebetwcen.
`
`In order to facilitate the assembly of the front and back
`suhassemblics. a weld ring 310 can be attached to the first end
`of the metal body 304. The weld ring can be attached to the
`metal body by any appropriate attachment process. such as by
`brazing. Brazing is a process well known in the art and will
`not be discussed in detail herein. In order to facilitate assem-
`
`bly and to ensure the proper placement of the weld ring 310
`relative to the metal body 304. the weld ring can be made to be
`self-jigging. Particularly. the weld ring 310 can have a lip
`region 314 that is formed to mate with a recess region 312 of
`the metal body 304. The weld ring can have a knife edge 318
`on one end to facilitate welding of the ring to a mating weld
`ring as discussed below. The weld ring can l1avc approximate
`dimensions in one embodiment of 1.7 inches in diameter by
`0.2 inches in length. The weld ring can be made of any
`appropriate material, such as a nickel alloy.
`FIG. 3 (in) also shows an access hole 320 extending from the
`back of the metal body (here from the back of the cooling
`cylinder 316] to the side ofthe blind hole 308. The access hole
`320 can be used for filling ofthe lamp assembly with gas. such
`as through the use of a copper tube (not shown) that is brazed
`or otherwise connected into a recess 322 at the back of the
`
`body. The access hole 320 can extend up to a circular gap
`region 324 around the anode 3 02, where the blind hole 308 is
`not in direct contact with the anode. The gas passageway
`through the access hole can extend into the circular gap region
`324 so that the interior of the lamp is accessible for pumping
`and filling. in this way, the lan1p can be filled without having
`to extend the access hole 320 through to the reflector. thus
`preserving the reflector surface from a hole that could reduce
`the light collection capability of the reflector.
`A back assembly 400 in accordance with another embodi-
`ment is shown ir1 FIG. 4(a). In this assembly. an anode 402
`again can be brazed into a blind hole contained in a cooling
`cylinder 408 ofa metal body 404. Once the anode is attached.
`a drop-in reflector 414 can be maneuvered into the reflector
`cavity 406 ofthe metal body. The drop-in reflector can be any
`appropriate reflector. such as a reflector Consisting ofa sub-
`strate such as electrofomted nickel. aluminum. ceramic.
`quartz, or glass, and a reflective film coating such as silver or
`a dichroic multilayer fihn. The reflector 414 can be formed
`using any appropriate mechanism known in the art. such as
`machining or molding. The drop-in reflector 414 can have a
`central opening or aperture (not shown) that is slightly larger
`than the ci rcumfercnce ofthe anode 402, such that the anode
`can help to position the reflector 414 as the reflector is being
`moved into the cavity 406. The drop-in refiector also can have
`a circumferential ridge 418 that is shaped to mate with a
`reflector step 416 formed in the first end of the metal body
`408. The circumferential ridge 418 allows the drop-in retice-
`
`3o
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`between separate metal body and heat sink assemblies, thus
`providing more efficient cooling. The position ofthe heat sink
`about the metal body allows for heat transfer from the metal
`27
`27
`
`

`
`7
`
`8
`
`US 7,679,276 B2
`
`body. As the anode typically is the hot spot in the latnp and
`requires sulllcient thennal transfer, the anode can be mounted
`directly to the tnetal body to act as a heat-conductive rnount-
`ing. The fins 506 of the heat sink 504 also can be a part ofthe
`metal body of the back assembly. Methods for forming a heat
`sink are well known and will not be discussed in detail herein.
`The heat sink can be made of any appropriate material and of
`any appropriate design providing sullicient heat removal.
`FIG. 5{,f) shows a view of a lamp body 550 with a back
`assembly having a plurality of integrated heat sinks in accor-
`dance with another etnbodirnent.
`to
`For each back subassernbly described with respect
`1" IGS. 3-5. it is necessary to provide a complimentary front
`subassembly. One such front assembly 600 is shown in the
`embodiment of FIG. 6(a). In this assembly, a sleeve member
`604 is used to seal the lamp interior including a mount for a
`liglit-transmitting window 602. The sleeve can be made of
`any appropriate material_. such as a tungsten-copper compos-
`ite or I<Zovar®. and can be formed from any appropriate pro-
`cess such as a MIM. machining. or drawing process. Kova1'®.
`a registered trademark ofWestinghouse Electric Corporation.
`is a nickel—iron—cobalt controlled—expansion alloy containing
`29% nickel. The coefficient of expansion of such an alloy.
`which decreases with rising temperature to the inflection
`point. cart match the expansion rate of materials such as
`ceramics. These alloys often are used for glass-lo-metal seals
`in applications requiring high reliability or resistance to ther-
`mal
`shock. Examples
`include high-power
`transtnitting
`valves. transistor leads and headers. integrated circuit lead
`frames. and photography flash bulbs.
`The dimensions of an exemplary sleeve are on the order of
`about 1.6 inc hes in diameter (tap eri rig to about 0.8 inches} and
`about 0.25 inches in length. As discussed above. the window
`can be made o fany appropriate material capable oftrar1smit-
`ting light and surviving at the high operating temperatures.
`such as sapphire, which also is capable of beingjoined to the
`sleeve material by a process such as brazing. A sapphire
`window can be coated, such as with a dichroic coating to
`reflect andfor absorb certain bandwidths of light. The sleeve
`on the front assembly also can provide support and position-
`ing for a cathode 606 of the lzunp. The cathode can be any
`appropriate material. such as is described with respect to the
`anode above. The positioning ofthe cathode can be controlled
`through use of a single strut 608. The strut 608 can have a
`shape at a receiving end for at least partially surrounding an
`end of the cathode 606. The cathode can be attached to the
`
`strut by any appropriate mechanisrn. such as by brazing. The
`single strut 608 can be received by a slot 61 0 in the sleeve 604.
`such that a precise positioning of the strut and cathode can be
`obtained. The strut 608 can be made with a stop or a notch to
`control the axial position of the cathode 606 with respect to
`the anode of the back assembly, in order to ensure a pro per arc
`gap distance between the electrodes. The sleeve also can have
`an additional number of struts extending to support the cath-
`ode. Each of the struts can extend to approximately a central
`axis of the sleeve in one embodiment. fortning a half-bar stntt
`that only connects to the sleeve at a singe location.
`The sleeve 604 can have a circumferential lip 620 that cart
`self-align the sleeve with respect to an insulating spacer 612.
`An insulating spacer typically is used to electrically isolate
`the anode and the cathode as known in the art. and can be
`formed from a ceramic material such as aluminum oxide. The
`insulating spacer can have a cylindrical step. or an outer
`diameter, that is designed to be received by the circumferen-
`tial lip 620 of the sleeve 604, such that the insulating spacer
`and sleeve are maintained in a desired orientation with respect
`to each other. An exemplary spacer can be about 2.2 inches in
`
`diameter. The spacer and sleeve can bejoined by any appro-
`priate means, such as by brazing the cylindrical step of the
`spacer 612 to the circuniferential lip 620 of tl1e sleeve 604, or
`by face brazing the Hat region 622 of the sleeve 604 to a
`mating flat region (not shown) on the spacer. The insulating
`spacer 612 also can have another cylindrical step 616 posi-
`tioned on the side opposite the sleeve 604. This step 616 can
`be shaped to receive a weld ring 614. such as a nickel-iron-
`cobalt control led-expansion alloy weld ring described with
`respect to FIGS. 3-5