CA2226596A1 - Lamp assembly, heater and base - Google Patents

Abstract

A lamp assembly is provided which includes a lamp, a lamp base attached to the lamp, and a lamp heater. One or more abutment regions of the lamp and the lamp base mate with one another to provide axial and rotational orientation of the lamp relative to the lamp base. The lamp heater conforms to the surface of the lamp and may be bonded thereto by an adhesive. The lamp heater may include a heater element and thermistor adjacent to a surface of the lamp. The lamp, lamp heater and thermistor are connected to a connector. A thermal breaker is connected to the heater. The thermal breaker provides a safety device to control maximum lamp temperature. The thermistor controls the operating temperature of the lamp. The lamp assembly may include a display device wherein the lamp is secured to the display device.

Description

.

EXPRESS MAIL NO.: TB862 878 566US
TITLE: ATTORNEY DOCKET NO.: 96-1-328 LAM:P ASSEMBLY, HEATER AND BASE
CROSS-REFERENCE TO RELATED APPLICATIONS
This application discloses information cl~im.-d in Attorney's Docket Nos. 96-1-319 and 96-2-102, filed concurrently herewith.

TECHNICAL FIELD

The present invention relates to a lamp assembly, and more particularly to a lamp assembly useful with a display device such as, for example, an automobile i~ clll cluster panel BACKGROUND ART

A Llmp assembly has various uses in various industries. For example, a lamp assembly may be provided which includes a display device.
Without limitation, an example of such a display device is an automobile il~Llumelll cluster panel. Such a panel typically contains 13 to 28 wedge base inc~n-lescPnt automotive lamps which serve as light sources for the panel. The bases of such lamps cause many problems. For example, typically such wedge base in~n-lesc~Pnt automotive lamps are made by one m~nnf~tllrer and the sockets into which such lamps are inserted are macle by another. When assembled, this can result in questionable reliability, varying coil robustness and lirnited life. In addition, there is a tendency for the contact wires of wedge base in~ntlescent automotive lamps to flatten when subjected to vibration such as that normally incurred, for example, in an automotive environment. This can lead to i-~t~ ...-ill~ .-1 or total lamp failure. In some automotive applications, such a wedge base lamp will actually inadvertently fall out of its socket and lay visible in the instrument cluster panel.

A filrther shortcoming is that such wedge base lamps operate at current levels of about 3.5 amps to 7.5 arnps (50 to 105 watts), at tc~ cldlllre EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 levels above 200~ C. and provide only 5 to 8 lumens per watt. Such levels limit the design of the lamp envelopes available and the materials used in the fabrication thereo~ Further, such hot lamps typically have a life c~l.e~ cy of only 500 to 2500 hours at best. Such a limited lamp life c~e~ cy is not consistent with present automotive warranties of 10 years/100,000 miles.

Tn~ntlescçnt lamps have been the primary light source for automotive lig]lting due to their ability to light in cold conditions. However, the use of a fluorescent lamp is known in the automotive art. For example, it is known to use a submini~tllre fluorescent U-shaped lamp as a light source in an automotive instrument cluster panel. A single insulative plastic base is used to house both ends of such U-shaped lamp as well as a he~lder-type electrical connector provided for ~tt~ ment to a controller circuit board. One disadvantage of such a base is that the electrical cormections between the lamp and the connector, and the electrical cormections between the connector and the circuit board, are typically effected by soldering. Such fluolescenl lamps are also difficult to operate in cold environments.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide an improved lamp asslembly.

It is another object of the present invention to provide a single,integrated lamp assembly of high reliability, improved efficiency and low opcl~ling t~ dl~lre.

- CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 It is a further object of the present invention to provide such a single, integrated fluorescent lamp assembly to replace the use of multiple inc~ndescent lamps.

Yet another object of the present invention is to provide such a single, integrated lamp assembly to replace the multiple in~n-lçscent lamps used in automotive applications.

Sti]ll another object of the present invention is to provide such a single, integrated lamp assembly in an automotive instrument cluster panel.

It is another object of the present invention to provide such a single integrated lamp assembly for use in an application wherein the lamp operates at a t~ln~ below about 100~ C., has a minimllm lamp life of about 8000 hours, has a minimum efficiency of about 25 lumens per waltt, has improved robustness relative to inc~nflesc~nt lamps, and can be produced in di~lellt colors and in varying lengths.

This invention achieves these and other objects by providing a lamp assembly which comprises a lamp having lamp conductors mechanically and~ electrically connected thereto. An insulative lamp base is attached to the lamp. A heater element is provided adjacent to the lamp. The heater element comprises heater conductors electrically and mechanically connected thereto. A thermistor is provided adj~r~nt the lamp. The thermistor has th.?rmi.~tor conductors electrically and mechanically connected thereto. A thermal breaker is electrically and mechanically connected to the heater element. A connector is electrically and mechanically connected to the lamp conductors, the heater conductors and the thermi~tor conductors. The lamp assembly may also comprise a display device wherein the lamp is secured to such lamp device.

96328~W0RD/APPLN

EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 BRIEF DESCRIPTION OF THE DRAWINGS

This invention may be clearly understood by reference to the ~ hP~l dra~wings in which like r~r~lence numerals designate like parts and in which:

FIG. 1 is a p~l~el;live view of one embodiment of a lamp assembly of the present invention;

FI(J. 2 is a perspective view of the lamp of FIG. l;

FI(}. 3 is aLn exploded view of one embodiment of an insulative lamp bas,e of the present invention;

FIG. 4 is a plan view of one embodiment of a lamp heater of the presentinvention;

FIG. S is a diagrammatic rep.ese~ lion of one embodiment of a heating element of the present invention;

FIG. 6 is a pel~l)e~ e view of one lamp base half of the insulative lamp base of FIG. 3;

FIG. 7 is a plan view of the lamp base half of FIG. 6;

FIC.. 8 is a plan view of one embodiment of one lamp base half of the present invention having (a) one end of a lamp (in phantom lines); (b) a the]mal breaker; and (c) a lamp conductor (in phantom lines), shown mounted therein;

CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 ~ PAGE60F25 FIG. 9 is a plan view of a lamp base half of the type depicted in FIG. 8 ha~ting (a) an opposite end of a lamp (in phantom lines) and (b) a plurality of conductors (phantom lines), shown mounted therein; and FIG. 10 is a plan view of another embodiment of a lamp assembly of the present invention.

BEST MODE FOR CARRYING OUT THE rNVENTION

For a better underst~n-ling of the present invention, together with other ancl further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims taken in conjunction with the above-described drawings.

Re~erring now to the drawings with greater particularity, FIG. 1 depicts a larnp assembly compri~ing lamp 12, insulative lamp bases 14 ~ rhed to the lamp, heater element 16 and thPrmietor 18 ~dj~c~nt the lamp, thermal breaker 20 electrically and mPrll~nically connected to the heater element, ancl connector 22 electrically and mech~nically conn~cted to the lamp, hea.ter element and thrrmi.~or by conductors 24 illustrated as a wire h~rnes.c Without limitation, the lamp assembly of FIG. 1 is a submini~t..re lamp assembly for use in automotive applications. It will be readily unclerstood by those skilled in the art that the present invention is applicable to other types of lamp assemblies for use in other applications, and. that the lamp of the present invention is not limited to any particular con~iguration or ~limen.cions discussed herein.

In l~e embodiment depicted in FIGS. 1 and 2, and without limitation, lamp 12 is an arc discharge lamp such as a conventional cold cathode 96328~W0RD1APPLN

CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 submini~h-re mercury arc discharge fluorescent lamp. Lamp 12 is elongated and hubular and extends in the direction 26 of a longihudinal axis 28 from a first end 30 to an opposite second end 32. Typically, a submini~h-re fluorescent lamp such as lamp 12 will include a glass hube 34 a phosphor coating 36 on the inside of the tube wall, a cathode end 38. and one or more lead wires 40, 42 ~ nlling from each hube end.
Thermal breaker 20 is positioned in close proximity to lamp cathode end 38.

The submini~h-re fluorescent lamp 12 may be of the type which opeldles under 100~C. and provides at least about 25 lurnens per watt co~llpaled to 5 to 8 lumens per watt provided by conventional in-~n-lescent lamps.
Such lamp 12 typically will provide at least 8000 hours of lamp life and have a color telll~ re of about 5300~K.. Lamp 12 is more robust than conventional in~n~lesc~nt lamps, larnp 12 having c~thocles rather than coils. Lamp 12 is also very adaptable, such lamp being available in dirl~clll colors and in di~.ellt lengths. Without limitation, a typical lamp 12 will be about 300mm in length and have a ~ nnPt~r of about 7mm.

In lhe embodiment of FIG. 2, the ends 30 and 32 of lamp 12 include lc~ccli~e flat press seals 44 and 46 through which respective lead wires 40 and 42 extend in a conventional manner. The lamp of the present invention may be provided with one or more abuhment regions. For example, in the embodiment of FIG. 2, press seal 44 of lamp 12 includes two abutment regions in the form of recesses 48 and 50 which extend inta, opposite surfaces at opposite edges of press seal 44. Similarly, press seal 46 includes two abutment regions in the form of lccesses 52 and 54 which extend into opposite surfaces at opposite edges of press seal 46.
Alternatively, recesses 48, 50, 52 and 54 may be in the form of CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 protuberances which extend from respective press seals 44 and 46. The ful1ction of such abutment regions will be described hereinafter.

In the lamp assembly of the present invention, an insulative lamp base may be provided to which the lamp is att~rh~rl For example, in the errlbodiment of FIG. 1, there are two plastic insulative lamp bases 14 in the form of a first lamp base housing 56 and a second lamp base housing 58.

Lamp base housing 56 is mechanically ~tt~l~h~cl to end 30 of lamp 12 and lamp base housing 58 is mPch~nically ~tt~rhPd to end 32. In a p~erell~d err~bodiment, lamp base housings 56 and 58 are identical, each including identical base halves 56', 56" and 58', 58", r~ye~ ely. Without limitation, lamp base halves 56',56" and 58',58" may be fabricated using conventional procedures. For exarnple, such lamp base halves may be molded from a plastic m~teri~l such as, without limitation, nylon or polypropylene. In a ylcfell~d embodiment, such plastic material is glass-filled, high telll~.dlul~ PPA (polyphth~l~mide) which will be effective at tenlyc;ldlul~s of about -40~C. to 165~C..

In fhe embodiment of FIG. 3, one example of such a lamp base housing is illustrated. For purposes of illustration, lamp base housing 58 is depicted in FIG. 3, it being understood that lamp base housing 56 is identical thereto. Referring to FIG. 3, lamp base housing 58 extends in a direction 60 of a longitudinal axis 62 from a first end 64 to a second end 66. Lamp base housing 58 comprises a plurality of openings each of which extends in direction 60 from end 64 to end 66. One such opening 68, formed by connecting the two m~çh~nically connecting base halves 58', 58" of lamp base housing 58, is configured to mate with end 32 of larnp 12 and comprises one or more surfaces having one or mor abutment regions configured to mate with a respective abutment region 9632B~WORD/APPLN

CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 of the lamp 12. For example, the portion of opening 68 of base half 58"
depicted in FIG. 3 comprises a first surface 70 which comprises an abutment region which is configured to mate with a respective abutment re~;ion of press seal 46 as described hereinafter. B~ half 58' comprises an identical abutment region (not shown). In those instances where the abutment regions of press seal 46 of lamp 12 are in the form of recesses 52, 54, the mating abutment regions of lamp base halves 58',58" will be in the form of mating protuberances 72, one such protuberance 72 of base half 58" being illustrated in FIG. 3. In those instances where protuberances are substituted for recesses 52, 54 of lamp 12, mating recesses will be substituted for protube,ances 72 of lamp base halves 58',58". End 30 of lamp 12 will be inserted into and mate with an identical lamp base housing 56 in the same manner, protuberances 72 of lamp base halves 56',56" mating with respective recesses 48,50 of press seal 44. When using lamp base housings 56, 58 of the type depicted in FIG. 3, the ends 30, 32 of lamp 12 are inserted into respective openings 68 of ~ e~;live lamp base housings 56, 58, the mating al~ullllen~ regions providing axial and rotational orientation of the lamp relative to the lamp b~ housing. To this end, lamp ends 30, 32 are inserted into respective openings 68 of lamp base housings 56 and 58 such that each protuberance 72 of lamp base halves 56',56" mates with a respective recess 48, 50 of lamp 12, and each protuberance 72 of lamp base halves 58',58" mates with a respective recess 52, 54.

In the embodiment of FIG. 1, heater elçm~nt 16 is positioned a~ c~nt lamp 12 and has heater conductors electrically and mechanically connected thereto. Without limitation, heater element 16 may be in the forrn of a resistive foil heater which comprises one or more foil traces as described in more detail hereinafter. The thermistor 18 is also positioned adjacent lamp 12 and has thermistor conductors electrically and CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 mP~h~nically connected thereto. Thermal breaker 20 is electrically and mPçh~nically connPctecl to heater element 16.

The heater element 16 and thermal breaker 20 may be electrically and mechanically conn~cted together to form a lamp heater useful in practicing the present invention. Although useful in various applications, the lamp heater of the present invention is particularly useful in heating a submini~tllre fluorescent lamp useful, for example, in automotive applications. In such applications, the lamp heater of the present invention facilitates operation of a highly reliable and efficient low power (about 1.5 amps starting current, 0.6 amps op~ g current) integral single lamp assembly, such as the lamp assembly depicted in FI(i. l, in cold weather requirements. In a plcr~.lcd embodiment, the heater element 16, th~rmi~tor 18, thermal breaker 20, and connector 22 are connected together to form one embodiment of an integral lamp heater of the present invention. Thermal breaker 20 provides a high tempel~ e safety device, and th~rmi~tor 18 controls the degree of heat.
An example of such a lamp heater is depicted in FIG. 4. In particular, a lan~p heater 74 is provided which comprises a heating element 16 which comprises a backing material 76, a layer of bonding material 78 and lengths of foil traces 80 and 82 bonded to the bonding material. In a plefe.led emb~ m~nt foil traces 80 and 82 have a somewhat st.~cnllille pattern to increase the length and therefore the effective heating area of the traces. When used with a submini~tl-re fluorescent lamp which is about 300mm in length and about 7mm in ~ nnçt~r a pl~fc,~l~d length of a serpentine heater element 16 will be about 257mm to 258mm from end to end. In a preferred embodiment, backing material 76 is a flexible polyamide film sold by E. I. du Pont under its tradem~rk KAPTON~, and bonding material 78 is a silicon pres~ulc-sensitive adhesive sold by FLE,Xcon Company, Inc. of Spencer, Massachusetts under its tr~clçm~rk DENSIL~. In a preferred embodiment, the KAPTON~ polyamide film EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-t-328 is purchased with the DENSIL~) bonding material coated thereon, and the foil traces 80,82 are adhered to such coated substrate which may then be adhered directly to lamp surface 84. The flexible KAPTON~
substrate is conformable to the rounded surface 84 of the tubular lamp 12. The DENSIL~ adhesive is particularly useful at elevated lamp tempcld~ ,s. A pl~r~ d form of the DENSIL~ adhesive is flame retardant and thPrm~lly conductive. The rç~ict~nce heater element 16 described herein operates at an input of about 13.5 volts D.C., with an op~,ldling range of about 9.0 to 16.0 volts D.C. M~Lil11U111 optldlii~g current is about 2 amps and rç~i~t~n~e is about 17.69 Ohms + 10% (10.3 watts reference). Such a lamp element 16 has an ambient op~,ldlillg telllpcldl lre of about -40~C. to 159~C. and a storage telll~ldlulc; of about -40~C. to 165~C.. The life of such lamp is about 10,000 hours, and it has a high W rating.

In ~m alternative embodiment diagrammatically depicted in FIG. 5, the heating element 16 is illustrated as compri~ing a backing material 86, and layers of bonding m~teri~l~ 88 and 90 with lengths of foil traces therebetween. Only one foil trace 92 is depicted in FIG. 5. Foil trace 92 has a first surface 94 a second surface 96. Bonding m~tÇri~l 88 is in contact with an inner surface 98 of the backing material 86. Surface 94 of J'oil trace 92 is in contact with bonding material 88 and is thereby adhered to the inner surface 98 of the backing m~tçri~l 86. In addition, surfàce 96 of foil trace 92 is in contact with bonding m~tÇri~l 90 which serves to bond the heating element 16 to the lamp 12 such that the heating element is ~ub~ lly contiguous with a portion of surface 84 of the lamp. With reference to FIG. 4, the thermal breaker 20 is electrically and mechanically connected in series to the length of foil traces 80 and 82. To this end, foil traces 80 and 82 include respective tabular end segments 100 and 102 which are soldered or welded to respective leads 104 and 106 of the thermal breaker 20. Thermal breaker EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 20 is placed in close proximity to the high heat source lamp cathode end 38. Thermal breaker 20 controls the maximum temperature of lamp 12, and in a plcr~,led embodiment includes a resettable safety switch. In this manner, a safety device is provided to the extent that if the lamp telll~Jcldlule rises above a norrnal opcldlil1g temperature, the thermal breaker opens thereby breaking heater continuity until such temperature drops below the opcldling lel"pe,dlllre at which time the thermal breaker closes again to allow the resumption of heater collLilluily. A thermal breaker sold by Texas Instrurnents, Inc. of Attleboro, ~ s~rhll-eett~
under catalogue no. 6MM01AA has been found to be particularly useful in the lamp heater of the present invention. The input of such thermal breaker is about 13.5 volts, and the current is about 4 amps (m~ximllm inrush) and about 2 arnps (maximum op~.dlillg). The lelllpeldllre ratings are about 75~C. ~ 10~C. (switch te"~pe.dlllre), 40~C. to 105~C.
(operating le~pc~dlllre3 and 40~C. to 165~C. (storage tc",peldlulc). The p,cre"cd style is 6mm without nickel strips. Such thermal breaker measures about 3mm x 6mm x 18.5mm and fits nicely within the lamp base housing 56 as described herein.

Connector 22is electrically and mech~nically conn~cted to the length offoil traces 80 and 82 and to the therrnistor 18. To this end, foil traces 80 and 82 include ,c;s~cli~re tabular end segm~nts 106 and 108 which are soldered or welded to one end of respective conductors 110 and 112.
The other end of conductors 110 and 112 are electrically and mechanically connected to connector 22 in a conventional manner.

Thermistor 18 comprises thermistor conductors 114 and 116 which are also electrically and mechanically connected to the connector 22 in a conventional manner.

Y0~ 1W~K~JAPPLN

EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 In the embodiment of FIG. 1 the thermistor 18 is attached directly on the lamp 12 by tape 120. Tape 120 may be high telllpeldlul~ and optically clear so as not to interfere with the illumination of lamp 12. Thprmictor 18 controls the O~ld~ g telllpcldlul~ of lamp 12 in a conventional manner to stabilize lamp telllpeldlllre at its o~ldlillg telllpeldlul~. A
thermistor sold by Inter-Technical Group, Inc. of Elmsford, New York under catalogue no. Uppermost #NA1036KlB-160(03) (Type NTC) has been found to be particularly useful in the lamp heater of the present invention. The resistance of such th~rmictor is about lOK W + 10% at 25~C. and about 3K W + 10% at 55~C. The telll~ldl~lre coefficient of resict~.lce at 25~C. is about -44%/~C., and the thermal time co~ t is above 25 seconds maximum. The o~ldlillg tellllxldl~e is about -40~C.
to l05~C. and the storage telll~ldlul~ is about -40~C. to 165~C. The lead wire is 24-28 gage with about 1.25mm maximum insulation. When used with a cllbmini~tnre fluorescent lamp 12 having a length of about 300mm and a width of about 7mm, such a th~rmi.ctor is positioned about lOOmm from the distal end of end 32 of the lamp.

The embodiment of the lamp heater of the present invention described herein and depicted in FIGS. 4 and 5 allows a submini~tnre mercury arc discharge fluorescent lamp to be readily heated up to and stabilized at its O~ldlillg tem~ldlule, even in automotive applications which may be subjected to cold telll~ldlules. Such a heater ~sembly provides a simplified, compact ~sembly with a minimllm number of wire connections. It must be emph~ci7Pcl that the lamp heater of the present invention is not limited to use with the lamp type, size or configuration described herein. Regardless of the application, a ~ro m~int~n~ e, long life lamp assembly is provided in accordance with the present invention.

CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 In the lamp assembly depicted in the drawings, each lamp base housing 56 and 58 comprises an opening 122 and an opening 124 as depicted with respect to lamp base hou ing 56 in FIG. 1. As depicted in more detail in FIG. 3, openings 122 and 124 each extend in direction 60 from end 64 to end 66, and opening 68 is positioned between openings 122 and 124.

In the embodiment of FIG. 2, lead wires 42 and 40 of lamp 12 are electrically and mPçh~nically connected to lamp conductors 126 and 128, respectively, in a conventional manner. For example, lead wires 42 and 40 are spliced to lamp conductors 126 and 128 at 130 and 132, e~ ely. Lamp conductor 128 may be f~ctPnPd to lamp 12 by tape 120 as depicted in FIG. 1. Lamp conductors 126, 128, heater conductors 110,112 and thPrmietor conductors 114,116 are electrically and mechanically connPcted to connector 22 in a conventional manner.

In the lamp assembly of the present invention, the thermal breaker extends into and is held in place by an insulative base housing. For example, in the embodiment of FIG. 1, the thermal breaker 20 extends into opening 124 and is held in place by the lamp base housing 56 as described in more detail hereinafter.

In the lamp assembly of the present invention, the various conductors extend through one or more of the lamp base housings. For example, in the embodiment of FIG. 1, heater conductors 110,112, thPrrnietor conductors 114,116 and lamp conductors 126,128 extend through the lamp base housing 58 to the connector 22. Lamp conductor 128 also extends through lamp base housing 56. The orientation of such conductors will be described in more detail hereinafter.

CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 FIG. 6 is an enlargement of lamp base half 58" of FIG. 3, viewed from end 66. FIG. 7 is a plan view of FIG. 6. Lamp base halves 58', 56' and 56" are identical to lamp base half 58". Lamp base half 58", and lamp base half 58', each comprise a portion of opening 68, a portion of opening 122 and a portion of opening 124. When lamp base halves 58',58" are connected together, rc~e~ e portions form respective openings 68, 122 and 124. The portion of the opening 68 of each lamp base half 58" comprises a first recess 134 which extends from end 64 towards end 66 and a second recess 136 which extends from end 66 towards end 64 and opens into recess 134. The surface 70 is adjac~nt recess 136. It will be a~parellt from FIG. 3 that each recess 134,136 of lamp base half 58" will be aligned with a respective recess 134,136 of lamp base half 58' when lamp base halves 58' and 58" are connected together to form opening 68.

As noted, lamp base half 58" compn~es a portion of openings 122 and 124. In particular, the portion of openings 124 and 122 of each lamp base half 58" comprises r~e~ e recesses 138 and 140 which extend from end 64 to end 66. It will be a~arcnl from FIG. 3 that each recess 138 and 140 of lamp base half 58" will be aligned with a respective recess 140 and 138 of lamp base half 58' when lamp base halves 58" and 58' are connected together to form openings 122 and 124 as described hereinafter. Each recess 138,140 col.lpllses a lcspe~ e base 142,144 and arespective protuberance 146,148 e~t~n-iing th~,cfiom. In the embodiment of FIG. 6, protuberances 146,148 are in the form of posts.
Recess 136 extends between surface 70 and an opposite surface 150 such that surface 70 is ~ r.çnt recesses 136 and 140, and surface 150 is adjacent recesses 136 and 138. Since lamp base halves 58' and 58" are identical, it will be al)p~cllt from FIG. 3 that when they are connected together, protuberance 72 of lamp base half 58" will face surface 150 of larnp base half 58', and protuberance 72 of lamp base half 58' will face 96328~W0R~/APPLN

CA 02226~96 1998-01-12 EXPRESS MAIL NO.:TB862878566US
ATTORNEY DOCKET NO.:96-1-328 surface 150 of lamp base half 58". In this manner, when assembled as depicted in FIG. 1, a protuberance 70 of lamp base halves 56',56" and 58',58" will extend into a respective recess 48,50,52 and 54 of lamp 12.
In the embodiment depicted in the drawings, surfaces 70 and 150 of lamp base halves 56', 56" and 58', 58" are configured to engage a c~e~live surface of a ~i,~e~;live press seal 44,46 of lamp 12 depicted in FIG. 2. In addition, each recess 134 is configured to sllbst~nti~lly conform to, engage and thereby support a respective tubular lamp end portion ~ cent press seals 44,46. In the embodiment of FIGS. 3, 6 and 7, recess 138 compli~es a protuberance 152 and recess 140 comprises a protub~ ce 154extentlingfrom~ e~ ebases 142and 144.

As best depicted in FIG. 7, the recess 138 comprises a region 156 whichextends from end 64 tow~.ds end 66 and a region 158 which extends from end 66 tow~ds end 64 and opens into region 156. Region 158 has a width 160 which is greater than a width 162 of region 156, the protuberance 146 being positioned in region 158 and the protuberance 152 being positioned in region 156. Similarly, recess 140 comprises a region 164 which extends from end 64 towards end 66 and a region 166 which extends from end 66 towards end 64 and opens into region 164.
Region 166 has a width 168 which is greater than a width 170 of region 164, the protuberance 148 being positioned in region 166 and the protuberance 154 being positioned in the region 164. Region 156 comprises opposing wall segments 172, 174 which extend vertically from base 142, and region 158 comprises opposing wall segment~
176,178 which extend vertically from base 142. The protuberance 146 is subst~nti~lly centered between wall segment~ 176,178, and the plolul~l~lce 152 is positioned against wall segment 172. Similarly, region 164 comprises opposing wall segments 180, 182 which extend vertically from base 144, and region 166 comprises opposing wall segment~ 184,186 which extend vertically from base 144. The 963Z8~WORD/APPLN

CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 protuberance 148 is subst~nti~lly centered between wall segmPnt.c 184,186, and the protuberance 154 is positioned against wall segm~nt 180. Wall segments 174 and 182 comprise a length 188,190, respectively, which protrude towards respective wall segments 172,180.
Protuberances 192,194 extend from re~,ccli~e wall segmPnt.~ 174,182 towards a protuberance 152,154, r~ccli~ely. Protuberances 196,198 extend from rc~cli~e wall segm~nt~ 178,176 towards protuberance 146, and protuberances 200,202 extend from respective wall segments 186,184 towards protuberance 148.

In considering assembling the lamp assembly depicted in the drawings, the lamp heater is att~r~l~ d to lamp 12 by adhesively bonding the heater element 16, and taping the thermistor 18, to surface 84 of the lamp, as described herein. With lcÇ~ ce to FIG. 8, the end 30 of the lamp 12 is then inserted into a lamp base half 56", which is identical to lamp b~e half 58", such that recess 134 supports a tubular end portion of the lamp and the protuberance 72 of lamp b~e half 56" protrudes into recess 50 of the lamp. To this extent, such mating protuberance 72/recess 50 serves to plo~.ly locate the end 30 of lamp 12 relative to the lamp b~e half 56". The lead wire 40 and lamp conductor 128 spliced thereto at 132 are wrapped around a protuberance such as, for example, protuberance 146, and the lamp conductor 128 is ext~n-led through the recess 138 such that the lamp conductor 128 is wedged between, and held in place by, facing surfaces of protul~.cu.ces 152 and 192. All ofthe conductors depicted in FIGS. 8 and 9 are illustrated ~ single pl~llo,l, lines for clarity of the drawings. However, it will be understood by those skilled in the art that such conductors will have a ~ mettqr. In the embodiment of FIG. 8, conductor 128 may have a diameter slightly greater than the rli.~t~n~ e between plolubc,~ulces 152 and 192 allowing such wedging to be effected. Subsequently, the thermal breaker 20 is inserted into recess 138 by inserting the thermal breaker between wall segm~nt 172 and wall 96328A~0RD/APPLN

CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 length 188 until the thermal breaker rests upon the protuberance 152.
When lamp 12, lamp conductor 128 and thermal breaker 20 are in place within lamp base half 56", an identical mating lamp base half 56' is fastened in place relative to lamp base half 56", as depicted in FIG. 3, to thereby enclose (a) the end 30 of lamp 12 within opening 68 and (b) the lengths of lamp conductor 128 and thermal breaker 20 within opening 124. When lamp halves 56', 56" are conn~cte~l together, protuberance 72 of lamp base half 56' will extend into lamp recess 48. In addihon, a portion of the thermal breaker 20, which will be- ext~n~ing out of the lamp base half 56", will extend into recess 140 of lamp base half 56' between wall segrn~nt 180 and wall length 190, and engage protuberance 154. Protuberances 152 and 192 provide strain relief for lamp conductor 128, and ~lolu~ ce 146 provides a guide for lead wire 40 and lamp conductor 128 welded thereto.

With lcrelcnce to FIG. 9, the end 32 of lamp 12 is inserted into a lampbase half 58" such that recess 134 supports a tubular end portion of the lamp and the protuberance 72 of lamp base 58" protrudes into recess 54 of lamp 12. To this end, such mating protuberance 72/recess 54 serves to propc,ly locate the end 32 of lamp 12 relative to the lamp base half 58". The lead wire 42 and lamp conductor 126 spliced thereto at 130 are wrapped around a protul~ lce such as, for cx~"~ , protuberance 148, and the lamp conductor 126 is extended through a portion of the recess 140 such that the lamp conductor 126 is wedged between, and held in place by, protuberances 148 and 202 by providing a conductor having a mPter slightly greater than the (li~t~nce between p~olulc~lce 148 and 202. Subsequently, lamp conductor 128, which extends from end 30 of lamp 12, and heater conductors 110,112 are inserted into recess 140 and wedged between protub~ ces 148 and 200. Although FIG. 9 depicts conductors 110,112 and 128 side by side for clarity of the drawing, in the preferred embodiment such conductors will be stacked upon each other CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 so that each such conductor may be similarly wedged between protuberances148and200. Th~rmietorconductors114,116willthenbe inserted into recess 138 such that conductor 114 is similarly wedged between protu~,d-lces 146 and 196, and conductor 116 is similarly wedged between protuberances 146 and 198. Conductors 110,112 and 128 will also be wedged between protuberances 154,194 and conductors 114,116 will also be wedged between protuberances 152,192.

When the conductors 110, 112, 114, 116, 126 and 128 are in place withinlamp base half 58", a mating lamp base half 58' is f~et~n~c~ in place relative to lamp base half 58", to thereby enclose (a) the end 32 of lamp 12 within opening 68, (b) the lengths of conductors 110, 112, 126 and 128 within opening 122, and (c) the lengths of conductors 114 and 116 within opening 124. In addition, when lamp base halves 58'58" are coupled together, protuberance 72 of lamp base 58' will extend into lamp recess 52. Protub~,~lces 146 and 148 provide guides for ~ iLi~e conductors as depicted in FIG. 9. Further, as depicted in FIG. 9, strain relief is provided by protu~,dllces 146, 196 for conductor 114; by protub~ ces 146, 198 for conductor 116; by prolu~ ces 152, 192 for conductors 114, 116; by protuberances 148, 202 for conductor 126; and by pl~lub~ ces 148, 200 and 154, 194 for conductors 110, 112 and 128.

In order to connect the lamp base halves together, each lamp base half comprises a clip member and a mating clip member which are connectable together. For e~ ple, with reference to FIG. 3, lamp base half 58" comprises a flexible conventional clip member 208 having a locking edge 210 which snaps into place relative to a latch locking ledge 212 of a mating clip member 214 of lamp base half 58'. Lamp base half 58' comprises a similar flexible clip member 208, only partially seen in FIG. 3, and lamp base half 58" comprises a similar mating clip member CA 02226~96 1998-01-12 EXPRESS MAIL NO.: TB862 878 566US
ATTORNEY DOCKET NO.: 96-1-328 214. Self-~lignmPnt tabs 216 are provided to facilitate ~lignm~nt of each clip member 208 with a respective mating clip member 214. Guide arms 218 are provided for facilitating positioning each lamp base housing 56,58 relative to a support surface. Conductors 110, 112, 114, 116, 126 and 128 extend from lamp base housing 58 to connecter 22 which provides a common connector head for such conductors.

In one embodiment of the lamp assembly of the present invention a display device is provided. Without limitation, such a lamp assembly is particularly useful when such display device is in the form of an automobile cluster panel. For ex~lll,le, in the embodiment illustrated in FIG. 10, a display device 220 is provided having a lamp 12 secured thereto. To this end, the lamp base housings 56,58 are secured to the display device to hold lamp 12 in place relative to the display device. In particular, the display device 220 comprises a display device housing 222, having an opening 224, and a clear plastic display panel 226 hPd to the display device housing. Lamp 12 is positioned between the display device housing 222 and the display panel 226. In particular, the first and second lamp base housings 56 and 58 are sandwiched between the display device housing 222 and display panel 226, and screws 228 secure the package together. In the embodiment of FIG. 10, lamp 12 is positioned ~dj~Pnt an edge 230 of the display panel 226, and the display panel may be mounted to the dashboard of a vehicle at mounts 232 in a conventional manner.

The embotlimPnt~ which have been described herein are but some of several which utili~ this invention and are set forth here by way of illustration but not of limitation. It is a~patent that many other embo.liment~ which will be readily ~p~lll to those skilled in the art may be made without departing materially from the spirit and scope of this invention.

96328~N0RD/APPLN

Claims (26)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS.

1. A lamp assembly, comprising:

a lamp;

an insulative lamp base attached to said lamp; and a lamp heater adjacent to a surface of said lamp.

2. The lamp assembly of claim 1 further comprising a display device, said lamp being secured to said display device.

3. A lamp assembly, comprising:

a lamp having lamp conductors mechanically and electrically connected thereto;

an insulative lamp base attached to said lamp;

a heater element adjacent to said lamp, said heater element having heater conductors electrically and mechanically connected thereto;

a thermistor adjacent said lamp, said thermistor having thermistor conductors electrically and mechanically connected thereto;

a thermal breaker electrically and mechanically connected to said heater element; and a connector electrically and mechanically connected to said lamp conductors, said heater conductors and said thermistor conductors.

4. The lamp assembly of claim 3 wherein said lamp is an elongated tubular lamp which extends in the direction of a longitudinal axis from a first end to an opposite second end, and further wherein said insulative lamp base comprises a first lamp base housing mechanically attached to said first end and a second lamp base housing mechanically attached to said second end.

5. The lamp assembly of claim 4 wherein said thermal breaker extends into and is held in place by said first insulative base housing.

6. The lamp assembly of claim 4 wherein one end of said lamp comprises a cathode, and further wherein said thermal breaker is adjacent said cathode.

7. The lamp assembly of claim 4 wherein said heater element and said thermistor are each attached to an outer surface of said lamp.

8. The lamp assembly of claim 7 wherein said heater element is attached to said lamp by an adhesive.

9. The lamp assembly of claim 4 wherein said lamp conductors, said heater conductors and said thermistor conductors extend from said elongated lamp, said heater element and said thermistor, respectively, through at least a portion of said second base and to said connector.

10. The lamp assembly of claim 9 wherein a lamp conductor extends through said first base.

11. The lamp of claim 10 wherein said thermal breaker extends into and is held in place by said first insulative base housing.

12. The lamp assembly of claim 11 wherein one end of said lamp comprises a cathode, and further wherein said thermal breaker is adjacent said cathode.

13. The lamp assembly of claim 11 wherein said heater element and said thermistor are each attached to an outer surface of said lamp.

14. The lamp assembly of claim 13 wherein said heater element is attached to said lamp by an adhesive.

15. The lamp assembly of claim 4 further comprising a display device, said lamp being secured to said display device.

16. The lamp assembly of claim 15 wherein said first lamp base housing and said second lamp base housing are secured to said display device.

17. The lamp assembly of claim 16 wherein said display device comprises a display device housing and a display panel attached to said display device housing, said lamp being positioned between said display device housing and said display panel.

18. The lamp assembly of claim 17 wherein said lamp is positioned adjacent an edge of said display panel.

19. The lamp assembly of claim 18 wherein said display device comprises an automobile instrument cluster panel.

20. The lamp assembly of claim 19 wherein said lamp conductors, said heater conductors and said thermistor conductors extend from said elongated lamp, said heater element and said thermistor, respectively, through at least a portion of said second base and to said connector.

21. The lamp assembly of claim 20 wherein a lamp conductor extends through said first base.

22. The lamp assembly of claim 21 wherein said thermal breaker extends into and is held in place by said first insulative base housing.

23. The lamp assembly of claim 22 wherein one end of said lamp comprises a cathode, and further wherein said thermal breaker is adjacent said cathode.

24. The lamp assembly of claim 22 wherein said heater element and said thermistor are each attached to an outer surface of said lamp.

25. The lamp assembly of claim 24 wherein said heater element is attached to said lamp by an adhesive.

26. The lamp assembly of claim 3 further comprising a display device, said lamp being secured to said display device.