CA2164711A1 - A phosphor coating arrangement for an electrodeless discharge lamp - Google Patents
A phosphor coating arrangement for an electrodeless discharge lampInfo
- Publication number
- CA2164711A1 CA2164711A1 CA 2164711 CA2164711A CA2164711A1 CA 2164711 A1 CA2164711 A1 CA 2164711A1 CA 2164711 CA2164711 CA 2164711 CA 2164711 A CA2164711 A CA 2164711A CA 2164711 A1 CA2164711 A1 CA 2164711A1
- Authority
- CA
- Canada
- Prior art keywords
- lamp
- lamp envelope
- envelope
- inner cavity
- phosphor coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/56—One or more circuit elements structurally associated with the lamp
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/38—Devices for influencing the colour or wavelength of the light
- H01J61/42—Devices for influencing the colour or wavelength of the light by transforming the wavelength of the light by luminescence
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J65/00—Lamps without any electrode inside the vessel; Lamps with at least one main electrode outside the vessel
- H01J65/04—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels
- H01J65/042—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels by an external electromagnetic field
- H01J65/048—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels by an external electromagnetic field the field being produced by using an excitation coil
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Discharge Lamps And Accessories Thereof (AREA)
Abstract
An electrodeless discharge lamp (10) having a lamp envelope (12) containing a fill of mercury and a rare gas is excitable to a discharge state by introduction of RF energy in close proximity thereto. A ballast circuit contained within the housing base portion (22) of the lamp is effective for generating the RF energy from conventional line power. The ballast circuit includes a core portion which extends within a re-entrant cavity (16) formed within the lamp envelope. During operation of the lamp, the re-entrant cavity portion is exposed to higher wall loading conditions than is the outer surface of the lamp envelope. These higher wall loading conditions require the use of comparatively more expensive rare earth phosphors (30) at the re-entrant cavity portion than are needed on the outer portion of the lamp envelope where it would be appropriate to utilize conventional halophosphate materials (32). In order to provide for two distinct phosphor coating materials in a single lamp envelope configuration and at a reasonable cost, such phosphor coating is done by coating the re-entrant cavity and the outer portion separately and then joining these components together to produce the finished lamp envelope.
The juncture point between the re-entrant portion and the outer envelope portion resides under an upper rim portion of the housing and is therefore not visible in the end lamp product.
The juncture point between the re-entrant portion and the outer envelope portion resides under an upper rim portion of the housing and is therefore not visible in the end lamp product.
Description
2`16 4 711 PCT/GB9S/00799 A PHOSPHOR COATING ARRANGEMENT FOR AN
ELECTRODELESS DISCHARGE LAMP
FIELD OF THE INVENTION
This invention relates to an arrange",e"l for providing ~ul,os,uhor 5 coati"y to a lamp envelope p."liol, of an electrodeless discl,afge lamp and more particularly, to such a ~I,osphor coating ar,d"ye"~ent as provides a more practical solution to the ~ e,~nces in wall loading ct ,ara~ tt:ri~lics that are ~.rese, ll in an elect, o-~elr-ss discl ,arye lamp.
BACKGROUND OF THE INVENTION
The electrodeless discharge lamp is projected as being a large co"lriL,utor in efforts to reduce elec1, icity demand thereby allowing electric utilities to forego the construction of costly power yelleralil)9 facilities.
The conl, ibution of the electrodeless ~l~scl ,arge lamp is eYrected to result from the increased energy e~i..;e)cy of such device as well as the 15 expected long life resulting from the cli. ";, ,clion of life inhibiting electrode elements. An example of an electrodeless discl ,arge lamp can be found in US Patent No. 4,010400 in which it is disclosed that an io"i~able medium can be disposed in a lamp envelope and excited to a discharge state by introduction of an RF signal in close ,~,roxi"~ily thereto such that 20 by use of a suit~ble phosphor visible light can be produced by such di;,cl,alye. ~n order to generate this RF signal the electrodeless iscl,arye lamp includes a ballast circuit arrangement dis~,osed in the lamp base such ballast circuit arrangement including a resonant tank circuit which utilizes a coil member extending into the lamp envelope to 25 inductively couple the RF signal to the jGI li~LlE medium.
As with any conven~ioual fluorescenl lamp the electrodeless discharge lamp requires a phosphor layer to convert the discharge from the ionized medium into visible light. ~t is the tvpical ,u, actice in fluorescent WO 95/27999 216 47~11 PCT/GB95/00799 ~ ' lamp manl Ihc~l Ire to use halophosphates and to obtain the required final color by blending phospl,ales together or by the ~ tio" of relatively small quar,Lilies of ,uhos,ul ,ale. Halophosphates are relatively inexpensive and are used e~le"sively because of their good efficacy, low cost and 5 wide range of ~ccepl~ble colors. In a co,n~.act fluoresce"l application wcr, wall loading cl ,a,d~ri~lics are typically of such a high value as to make the use of haa~,os,c~,ales i"appro,cridte hec~use of their tendency to .lele,iordle quickly under such high wall loading co"ditions.
In such cases, it is necessa~ to use co" ,paf~ ely more expensive rare 10 earth phos~Jl,o,~. In an electrodeless discharge lamp it has been found that the wall loading chara~eri~lics vary along ~ir~erenl pGIliolls of the lamp envelope bu~ that near the region of-the cavit~ sucrour~ding the coil me" Iber from which the RF signal is inductively coupled, the wall loading ~1 ,aracte, islic~ are surti. ;e~ y high as to preclude the use of 15 halopl~ospl~ales for such area. One way to alleviate the risk of using halo~Jhos~l ,ates and suffering degradation of the phosphor " ,alerial would be to coat the entire surface of the lamp envelope inner wall with the rare earth pl ,05~hale. Such a measure would allow for a long life light source I ,o~J_ver the cost of such a lamp will have been incfeased siy"irica"tly by 20 the use of the more expensive rare earth phos~hor. One other way to alleviate the problem is mask off certain portions of the inner wall of the lamp envelope and use a se,uaiale coalil ~y step for each of the .li~erel)l ,uhospllofs used. Such an ar,c"yelllent would also prove costly in that the manuf~ctllring operation needed to implement the masking and 25 multiple cGdling approach would be prohibitive.
Accordi.)gly, it would be advant~geo~s if a ,vl~ospl~or coati"y a" ange" ,enl could be provided for an electrodeless dis.:l ,arge lamp which was both cost effective as a result of using ~ e,t;"l ,C,1 105~JI ,0, ~ based onthe wall loading requirements and was easily implemented in a 30 manufacturing ,("ocess that did not include the ~1 Iditiol, of multiple steps WO 95/27999 2~i B 4 7 1 1 PCT/GB95/00799 such as masking and plural coating operations.
SUMMARY OF THE INVENTION
Based on the principles of the present invention there is provided in an electrodeiess ~ischarge lamp having a lamp envelope containing a 5 fill of mercury and a rare gas excitable to a discl,a,ye state upon the introrlllction of an RF signal ge"e,aled by a ballast circuit di~osed in a lamp base po, liOrl and wherein the lamp envelope is disposed in at least a partially surrounding relalior, to a coil member from which the RF signal is olJtp! ~t a ~hospl ,or coali"g ar, dl ~yel I ~e~ ll on the lamp envelope in a cost 10 effective manner and one which is easily implemented in a mass pror~(lction manuf~cturing process. An outer portion of the lamp envelope is ~isposed in a spaced apart relation to the coil member whereas an inner cavity ~.o,lio" e-~lendiny into the lamp envelope along the central axis thereof is sized to acco" " "od~te insertion of the coil member therein 15 and is in close ~.ro,ti",ity to the coil member thereby subjE_tiny the inner cavity ,~,o, lio" to higher wall loading values than that of the outer portion of the lamp envelope. A conl ,ectio" area of the lamp envelope is formed where the inner cavity ,uollioll is joined to the outer ~uo, lion of the lamp envelope, this connection area being disposed at the lower",osl portion 20 of the lamp envelope which is inserted into the lamp base for securing the lamp envelope to the lamp base. A rare earth ,cl,os~l,aLe co~ti"y is applied to the inner cavity ~o, lion whereas one of either a halophos,ol ,ale or fluorescenl pllospl,ale material is applied to the inner surface of the outer portion of the lamp envelope. The manufacturing operation of 25 joining the inner cavity ~Jolliol, to the outer portion of the lamp envelope is ,ue,~or"~ed after the phospl,ale co~linys are applied thereby obviating the need for masking procedures during the coating applications proce~Jure.
WO95/27999 216~4~ ~1 PCT/GB95100799 BRIFF DESCRIPTION OF THE DRAWINGS
This invention will be described more fully with re~er~nce to the drawings in which:
Figure 1 is an elevational view in section of an electrodeless lamp 5 constructed in accordaoce with the present invention.
Figure 2 is an elevational view in se~ion of the lamp envelope ollioll of the lamp of Fig. 1 showing the phospl,or coating a,ld"yer,l6l,l of the ~ures6' It invention.
DEl AILED DESCRIPTION OF THE INVENTION
As seen in Fig. 1 a low pressure electrodeless fluorescent lamp 10 includes a lamp envelope 12 having an outer envelope portion 14 and an inner portion i~enli~ied as re-er,L,anl cavity 16. The re-e"l,anl cavity 16 is essentially cylindrical in shape and eklen~ls within the outer envel "~e po,lio" 14 along the central axis thereof. Extending through the central axis of the re-enl-~l,l cavity 16 is an exhaust tube 18 which is shown extending beyond the point at which the re-e"llcl ll cavity 16 and the outer envelope po, lio,1 14 join to complete the lamp envelope 12 such juncture being identified as refer~nce 20.
The outer envelope portion 14 is illustrated as essentially the same shape as a conver,lio"al incandescel1~ reflector lamp product. However other configuralions of the outer lamp envelope 14 can be utilized equally as well; for i,lsl~nce the outer envelope 14 can be configured in the shape of a conver,liol,al A-line lamp product or a decorative globe lamp product.
Regardless of the shape of the outer envelope portion 14 the lower regions 12b and 14b to each of the outer envelope and re-entrant cavity po, liol ,s of the lamp envelope 12 defined as juncture 20 will reside inside of the upper rim region of the base housing 22. As will be ~isc~ssed in her~ i. ,a~ler in further detail by location of the juncture 20 at this point the WO 95/27999 ` PCT/GB95/00799 - 216~711 precision of the coating process for the fluorescent material can be somewhat relaxed. Moreover it can be appreciated that by use of a lamp manuf~ctllring process whereby the outer envelope ~.oi lio" 14 is formed se~.a,atcly from the forming process for the re-e"lranL portion 16 the 5 c~ati"g application can be accomplished for each pollion sepalalely before such portions are joined in the final lamp manufacturing step. In this manner the present invention allows for the use of a se~arale phos~l,or material application to the outer envelope po,lion 14 than is used for the re-er,l,anl portion thereby avoiding the need for masking off 10 one ,~u~lion while the other is being coated with a dirrerel,t phos~l,or ",~terial.
As further seen in Fig. 1 the electrodeless discharge lamp 10 of the presenl invention generates a torroidally shaped discharge 23 within lamp en~elo~.e 12. Such discharge 23 is generated upon the introduction of 15 radio frequency (RF) energy to the fill contained within the lamp envelo~.e such fill being of the convel,lio"al type used in slandard fluoresce,lt lamps. The RF energy is produced by a reso"anl circuit portion of a ballast circuit 24 disposed within the housing base 22. The resG"anl circuit portion includes an excitalion coil 26 having a core portion 26a 20 and a winding 26b and a capacitor 28. The ballast circuit drives the rt:sollalll circuit portion with a conditioned signal developed from line power.
By e~(cil~l;on and ",ai,lle"ance of the discharge 23 within the lamp envelope 12, it has been observed that the re-entrant portion 16 of lamp 25 envelope 12 experiences higher wall loading values (measured as Watts/cm2) than does the outer envelope portion 14. In order to provide a ~I,os~Jhor coating on the re-el,lra"l cavity 16 that will not deterio,dle over the life of the lamp 10 particularly given the expected long life of such an electro~eless discharge lamp 10, it is necessa~ to utilize a tri-30 pl,os,cl,or coating ~l~aterial on this region. As seen in Fig. 2 a tri-ph oslJI ,or coating " ,~lerial 30 is applied to the lamp envelope in the regioncovering the re-enlrai,l cavity 16 facing the interior space of lamp envelope 12. The tri-phosphor material 30 can be that malerial which is typically utilized on convenLio"al cor"~ æt fluorescenl lamps such " ,alerial 5 being readily available in the markelplace.
Unlike the wall loading co"dilions experie"ced by the re-e"tra,)l cavity 16 the outer envelope po,lio,l 14 of lamp envelope 12 are significantly lower and can acco" " "odate the use of the lesser ex,c,ensive halophosp h~td malerial, such ")alerial being the same p hos~ l ,or " ,~ rial 10 as can be utilized in larger conventional fluo,t:scent lamps such as 2 and 4 foot versions of such lamps. As seen in Fig. 2 the dirrefenl phosphor material 32 is illustrated as having a ~irrere, ll grain size as that " ,alerial 30 used on the re-e"l,~"t cavity. As further seen in Fig. 2 the illustrated lamp 10 is a rerle~or lamp and as such includes a reflective coating 34 15 disposed on the re-e,lt,~,lt cavity 16 and a portion of the outer envel~,e extending to a~,uro~i~, lately the equatorial region of the lamp envelope the dividing line being desiynaled as leferel,ce line A-A.
The coating ~.rocess utilized for coating each of the re-el,l,~"l and outer envelope portions 14 16 of lamp envelope 12 does not require a 20 precision operation inasmuch as the portion of the lamp envelope 12 at which the re-enl~anl cavity 16 and outer envelope 14 join juncture 20 is not visible in the end product but is covered by the upper rim of housing base 22. Further" ,ore in the manufacturing ope~iu" utilized for produced finished coated lamp envelopes 12 which are assembled with 25 the housing and ballast po, lions 22, 24 it can be appreciated that such manufacturing operation is facilitated by the fact that each of the lamp envelope portions 14 16 can be separately coated without the need for a masking process to accol ",oodate the separ~le coating malerials. After such se~ardle coating process the lamp envelope pG,lions 14 16 are 30 joined to form the finished lamp envelope thereby achieving a more cost WO 95127999 ~ ~ ~ 71 ¦ PCT/GB95100799 effective component in that the expensive tri-phosphor ",alerial is only used on the area where the wall-loading characteristics require the use of such expensive maLe,ial.
Although the above described embodiment co,~s~ tes the 5 pr~r,ed embodiment it should be ~nder~lood that n,o-liric~lions can be made lheft:lo without ~epa,~ from the scope of the invention as set forth in the appended claims.
ELECTRODELESS DISCHARGE LAMP
FIELD OF THE INVENTION
This invention relates to an arrange",e"l for providing ~ul,os,uhor 5 coati"y to a lamp envelope p."liol, of an electrodeless discl,afge lamp and more particularly, to such a ~I,osphor coating ar,d"ye"~ent as provides a more practical solution to the ~ e,~nces in wall loading ct ,ara~ tt:ri~lics that are ~.rese, ll in an elect, o-~elr-ss discl ,arye lamp.
BACKGROUND OF THE INVENTION
The electrodeless discharge lamp is projected as being a large co"lriL,utor in efforts to reduce elec1, icity demand thereby allowing electric utilities to forego the construction of costly power yelleralil)9 facilities.
The conl, ibution of the electrodeless ~l~scl ,arge lamp is eYrected to result from the increased energy e~i..;e)cy of such device as well as the 15 expected long life resulting from the cli. ";, ,clion of life inhibiting electrode elements. An example of an electrodeless discl ,arge lamp can be found in US Patent No. 4,010400 in which it is disclosed that an io"i~able medium can be disposed in a lamp envelope and excited to a discharge state by introduction of an RF signal in close ,~,roxi"~ily thereto such that 20 by use of a suit~ble phosphor visible light can be produced by such di;,cl,alye. ~n order to generate this RF signal the electrodeless iscl,arye lamp includes a ballast circuit arrangement dis~,osed in the lamp base such ballast circuit arrangement including a resonant tank circuit which utilizes a coil member extending into the lamp envelope to 25 inductively couple the RF signal to the jGI li~LlE medium.
As with any conven~ioual fluorescenl lamp the electrodeless discharge lamp requires a phosphor layer to convert the discharge from the ionized medium into visible light. ~t is the tvpical ,u, actice in fluorescent WO 95/27999 216 47~11 PCT/GB95/00799 ~ ' lamp manl Ihc~l Ire to use halophosphates and to obtain the required final color by blending phospl,ales together or by the ~ tio" of relatively small quar,Lilies of ,uhos,ul ,ale. Halophosphates are relatively inexpensive and are used e~le"sively because of their good efficacy, low cost and 5 wide range of ~ccepl~ble colors. In a co,n~.act fluoresce"l application wcr, wall loading cl ,a,d~ri~lics are typically of such a high value as to make the use of haa~,os,c~,ales i"appro,cridte hec~use of their tendency to .lele,iordle quickly under such high wall loading co"ditions.
In such cases, it is necessa~ to use co" ,paf~ ely more expensive rare 10 earth phos~Jl,o,~. In an electrodeless discharge lamp it has been found that the wall loading chara~eri~lics vary along ~ir~erenl pGIliolls of the lamp envelope bu~ that near the region of-the cavit~ sucrour~ding the coil me" Iber from which the RF signal is inductively coupled, the wall loading ~1 ,aracte, islic~ are surti. ;e~ y high as to preclude the use of 15 halopl~ospl~ales for such area. One way to alleviate the risk of using halo~Jhos~l ,ates and suffering degradation of the phosphor " ,alerial would be to coat the entire surface of the lamp envelope inner wall with the rare earth pl ,05~hale. Such a measure would allow for a long life light source I ,o~J_ver the cost of such a lamp will have been incfeased siy"irica"tly by 20 the use of the more expensive rare earth phos~hor. One other way to alleviate the problem is mask off certain portions of the inner wall of the lamp envelope and use a se,uaiale coalil ~y step for each of the .li~erel)l ,uhospllofs used. Such an ar,c"yelllent would also prove costly in that the manuf~ctllring operation needed to implement the masking and 25 multiple cGdling approach would be prohibitive.
Accordi.)gly, it would be advant~geo~s if a ,vl~ospl~or coati"y a" ange" ,enl could be provided for an electrodeless dis.:l ,arge lamp which was both cost effective as a result of using ~ e,t;"l ,C,1 105~JI ,0, ~ based onthe wall loading requirements and was easily implemented in a 30 manufacturing ,("ocess that did not include the ~1 Iditiol, of multiple steps WO 95/27999 2~i B 4 7 1 1 PCT/GB95/00799 such as masking and plural coating operations.
SUMMARY OF THE INVENTION
Based on the principles of the present invention there is provided in an electrodeiess ~ischarge lamp having a lamp envelope containing a 5 fill of mercury and a rare gas excitable to a discl,a,ye state upon the introrlllction of an RF signal ge"e,aled by a ballast circuit di~osed in a lamp base po, liOrl and wherein the lamp envelope is disposed in at least a partially surrounding relalior, to a coil member from which the RF signal is olJtp! ~t a ~hospl ,or coali"g ar, dl ~yel I ~e~ ll on the lamp envelope in a cost 10 effective manner and one which is easily implemented in a mass pror~(lction manuf~cturing process. An outer portion of the lamp envelope is ~isposed in a spaced apart relation to the coil member whereas an inner cavity ~.o,lio" e-~lendiny into the lamp envelope along the central axis thereof is sized to acco" " "od~te insertion of the coil member therein 15 and is in close ~.ro,ti",ity to the coil member thereby subjE_tiny the inner cavity ,~,o, lio" to higher wall loading values than that of the outer portion of the lamp envelope. A conl ,ectio" area of the lamp envelope is formed where the inner cavity ,uollioll is joined to the outer ~uo, lion of the lamp envelope, this connection area being disposed at the lower",osl portion 20 of the lamp envelope which is inserted into the lamp base for securing the lamp envelope to the lamp base. A rare earth ,cl,os~l,aLe co~ti"y is applied to the inner cavity ~o, lion whereas one of either a halophos,ol ,ale or fluorescenl pllospl,ale material is applied to the inner surface of the outer portion of the lamp envelope. The manufacturing operation of 25 joining the inner cavity ~Jolliol, to the outer portion of the lamp envelope is ,ue,~or"~ed after the phospl,ale co~linys are applied thereby obviating the need for masking procedures during the coating applications proce~Jure.
WO95/27999 216~4~ ~1 PCT/GB95100799 BRIFF DESCRIPTION OF THE DRAWINGS
This invention will be described more fully with re~er~nce to the drawings in which:
Figure 1 is an elevational view in section of an electrodeless lamp 5 constructed in accordaoce with the present invention.
Figure 2 is an elevational view in se~ion of the lamp envelope ollioll of the lamp of Fig. 1 showing the phospl,or coating a,ld"yer,l6l,l of the ~ures6' It invention.
DEl AILED DESCRIPTION OF THE INVENTION
As seen in Fig. 1 a low pressure electrodeless fluorescent lamp 10 includes a lamp envelope 12 having an outer envelope portion 14 and an inner portion i~enli~ied as re-er,L,anl cavity 16. The re-e"l,anl cavity 16 is essentially cylindrical in shape and eklen~ls within the outer envel "~e po,lio" 14 along the central axis thereof. Extending through the central axis of the re-enl-~l,l cavity 16 is an exhaust tube 18 which is shown extending beyond the point at which the re-e"llcl ll cavity 16 and the outer envelope po, lio,1 14 join to complete the lamp envelope 12 such juncture being identified as refer~nce 20.
The outer envelope portion 14 is illustrated as essentially the same shape as a conver,lio"al incandescel1~ reflector lamp product. However other configuralions of the outer lamp envelope 14 can be utilized equally as well; for i,lsl~nce the outer envelope 14 can be configured in the shape of a conver,liol,al A-line lamp product or a decorative globe lamp product.
Regardless of the shape of the outer envelope portion 14 the lower regions 12b and 14b to each of the outer envelope and re-entrant cavity po, liol ,s of the lamp envelope 12 defined as juncture 20 will reside inside of the upper rim region of the base housing 22. As will be ~isc~ssed in her~ i. ,a~ler in further detail by location of the juncture 20 at this point the WO 95/27999 ` PCT/GB95/00799 - 216~711 precision of the coating process for the fluorescent material can be somewhat relaxed. Moreover it can be appreciated that by use of a lamp manuf~ctllring process whereby the outer envelope ~.oi lio" 14 is formed se~.a,atcly from the forming process for the re-e"lranL portion 16 the 5 c~ati"g application can be accomplished for each pollion sepalalely before such portions are joined in the final lamp manufacturing step. In this manner the present invention allows for the use of a se~arale phos~l,or material application to the outer envelope po,lion 14 than is used for the re-er,l,anl portion thereby avoiding the need for masking off 10 one ,~u~lion while the other is being coated with a dirrerel,t phos~l,or ",~terial.
As further seen in Fig. 1 the electrodeless discharge lamp 10 of the presenl invention generates a torroidally shaped discharge 23 within lamp en~elo~.e 12. Such discharge 23 is generated upon the introduction of 15 radio frequency (RF) energy to the fill contained within the lamp envelo~.e such fill being of the convel,lio"al type used in slandard fluoresce,lt lamps. The RF energy is produced by a reso"anl circuit portion of a ballast circuit 24 disposed within the housing base 22. The resG"anl circuit portion includes an excitalion coil 26 having a core portion 26a 20 and a winding 26b and a capacitor 28. The ballast circuit drives the rt:sollalll circuit portion with a conditioned signal developed from line power.
By e~(cil~l;on and ",ai,lle"ance of the discharge 23 within the lamp envelope 12, it has been observed that the re-entrant portion 16 of lamp 25 envelope 12 experiences higher wall loading values (measured as Watts/cm2) than does the outer envelope portion 14. In order to provide a ~I,os~Jhor coating on the re-el,lra"l cavity 16 that will not deterio,dle over the life of the lamp 10 particularly given the expected long life of such an electro~eless discharge lamp 10, it is necessa~ to utilize a tri-30 pl,os,cl,or coating ~l~aterial on this region. As seen in Fig. 2 a tri-ph oslJI ,or coating " ,~lerial 30 is applied to the lamp envelope in the regioncovering the re-enlrai,l cavity 16 facing the interior space of lamp envelope 12. The tri-phosphor material 30 can be that malerial which is typically utilized on convenLio"al cor"~ æt fluorescenl lamps such " ,alerial 5 being readily available in the markelplace.
Unlike the wall loading co"dilions experie"ced by the re-e"tra,)l cavity 16 the outer envelope po,lio,l 14 of lamp envelope 12 are significantly lower and can acco" " "odate the use of the lesser ex,c,ensive halophosp h~td malerial, such ")alerial being the same p hos~ l ,or " ,~ rial 10 as can be utilized in larger conventional fluo,t:scent lamps such as 2 and 4 foot versions of such lamps. As seen in Fig. 2 the dirrefenl phosphor material 32 is illustrated as having a ~irrere, ll grain size as that " ,alerial 30 used on the re-e"l,~"t cavity. As further seen in Fig. 2 the illustrated lamp 10 is a rerle~or lamp and as such includes a reflective coating 34 15 disposed on the re-e,lt,~,lt cavity 16 and a portion of the outer envel~,e extending to a~,uro~i~, lately the equatorial region of the lamp envelope the dividing line being desiynaled as leferel,ce line A-A.
The coating ~.rocess utilized for coating each of the re-el,l,~"l and outer envelope portions 14 16 of lamp envelope 12 does not require a 20 precision operation inasmuch as the portion of the lamp envelope 12 at which the re-enl~anl cavity 16 and outer envelope 14 join juncture 20 is not visible in the end product but is covered by the upper rim of housing base 22. Further" ,ore in the manufacturing ope~iu" utilized for produced finished coated lamp envelopes 12 which are assembled with 25 the housing and ballast po, lions 22, 24 it can be appreciated that such manufacturing operation is facilitated by the fact that each of the lamp envelope portions 14 16 can be separately coated without the need for a masking process to accol ",oodate the separ~le coating malerials. After such se~ardle coating process the lamp envelope pG,lions 14 16 are 30 joined to form the finished lamp envelope thereby achieving a more cost WO 95127999 ~ ~ ~ 71 ¦ PCT/GB95100799 effective component in that the expensive tri-phosphor ",alerial is only used on the area where the wall-loading characteristics require the use of such expensive maLe,ial.
Although the above described embodiment co,~s~ tes the 5 pr~r,ed embodiment it should be ~nder~lood that n,o-liric~lions can be made lheft:lo without ~epa,~ from the scope of the invention as set forth in the appended claims.
Claims (3)
1. In an electrodeless discharge lamp having a lamp envelope containing a fill of mercury and a rare gas excitable to a discharge state upon the introduction of an RF signal generated by a ballast circuit disposed in a base portion of the discharge lamp, and wherein the lamp envelope is disposed in at least a partially surrounding relation to a coil member from which the RF signal is output a phosphor coating arrangement on said lamp envelope comprising:
an outer portion of said lamp envelope disposed in a spaced apart relation to said coil member;
an inner cavity portion extending into said lamp envelope along the central axis thereof and being sized to accommodate insertion of said coil member therein, wherein said inner cavity portion is subjected to higher wall loading values than those to which said outer portion of said lamp envelope is subjected;
a connection area of said lamp envelope connecting said inner cavity portion with said outer portion of said lamp envelope;
wherein a rare-earth phosphor coating is applied to said inner cavity portion of said lamp envelope; and wherein at least one of a halophosphate and a fluorescent phosphate material is applied to the inner surface of said outer portion of said lamp envelope.
an outer portion of said lamp envelope disposed in a spaced apart relation to said coil member;
an inner cavity portion extending into said lamp envelope along the central axis thereof and being sized to accommodate insertion of said coil member therein, wherein said inner cavity portion is subjected to higher wall loading values than those to which said outer portion of said lamp envelope is subjected;
a connection area of said lamp envelope connecting said inner cavity portion with said outer portion of said lamp envelope;
wherein a rare-earth phosphor coating is applied to said inner cavity portion of said lamp envelope; and wherein at least one of a halophosphate and a fluorescent phosphate material is applied to the inner surface of said outer portion of said lamp envelope.
2. A phosphor coating arrangement for a lamp envelope as set forth in claim 1 wherein during manufacture of said electrodeless discharge lamp said rare-earth phosphor coating is applied to said inner cavity portion and said at least one of a halophosphate and a fluorescent phosphor material is applied to said outer portion of said lamp envelope prior to said inner cavity portion being joined to said outer portion of said lamp envelope at said connecting area thereby avoiding a masking operation of any area of said lamp envelope during application of said phosphor materials on any other surface area.
3. A phosphor coating arrangement for a lamp envelope as set forth in claim 2 wherein said connection area between said inner cavity portion is joined to said outer portion of said lamp envelope resulting in a juncture point therebetween, and wherein said juncture point is disposed within said lamp base so as to be covered by an upper rim portion of said lamp base.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9407128A GB9407128D0 (en) | 1994-04-11 | 1994-04-11 | A phosphor coating arrangement for an electrodeless discharge lamp |
| GB9407128.9 | 1994-04-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2164711A1 true CA2164711A1 (en) | 1995-10-19 |
Family
ID=10753339
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2164711 Abandoned CA2164711A1 (en) | 1994-04-11 | 1995-04-06 | A phosphor coating arrangement for an electrodeless discharge lamp |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0702846B1 (en) |
| JP (2) | JPH08511652A (en) |
| CA (1) | CA2164711A1 (en) |
| DE (1) | DE69512166T2 (en) |
| GB (1) | GB9407128D0 (en) |
| WO (1) | WO1995027999A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| HU217752B (en) * | 1994-04-18 | 2000-04-28 | General Electric Co. | Electrodeless fluorescent reflectorlamp |
| DE102009025667A1 (en) * | 2009-06-17 | 2010-12-23 | Heraeus Noblelight Gmbh | lamp unit |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3928786A (en) * | 1973-07-02 | 1975-12-23 | Gen Electric | Fluorescent lamp having partitioned vapor discharge |
| US4010400A (en) * | 1975-08-13 | 1977-03-01 | Hollister Donald D | Light generation by an electrodeless fluorescent lamp |
| DE3019605A1 (en) * | 1980-05-22 | 1981-11-26 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH, 8000 München | LOW PRESSURE DISCHARGE LAMP |
| DE3139732A1 (en) * | 1981-10-06 | 1983-04-21 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH, 8000 München | LOW PRESSURE DISCHARGE LAMP BASED ON ONE SIDE AND METHOD FOR PRODUCING THE SAME |
-
1994
- 1994-04-11 GB GB9407128A patent/GB9407128D0/en active Pending
-
1995
- 1995-04-06 WO PCT/GB1995/000799 patent/WO1995027999A1/en active IP Right Grant
- 1995-04-06 CA CA 2164711 patent/CA2164711A1/en not_active Abandoned
- 1995-04-06 JP JP7526169A patent/JPH08511652A/en active Pending
- 1995-04-06 DE DE69512166T patent/DE69512166T2/en not_active Expired - Fee Related
- 1995-04-06 EP EP95914458A patent/EP0702846B1/en not_active Expired - Lifetime
-
2005
- 2005-09-21 JP JP2005274109A patent/JP2006059819A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JP2006059819A (en) | 2006-03-02 |
| EP0702846A1 (en) | 1996-03-27 |
| GB9407128D0 (en) | 1994-06-01 |
| DE69512166T2 (en) | 2000-05-31 |
| JPH08511652A (en) | 1996-12-03 |
| DE69512166D1 (en) | 1999-10-21 |
| EP0702846B1 (en) | 1999-09-15 |
| WO1995027999A1 (en) | 1995-10-19 |
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| EEER | Examination request | ||
| FZDE | Dead |