Improved compact reflector lamp unit construction

Abstract

 An improved compact reflector lamp unit (10) is disclosed having a construction enabling the length of the reflector bottom portion (20) to be reduced in order to avoid light escape thereat when the lamp unit is installed in existing socket fixtures. An electrically non-conductive hollow sleeve (22) physically connects the bottom portion of the reflector member to a hollow metal base (14) for this purpose. Various lamp embodiments employing such modified structural configurations are also described.

Description

[0001] This invention relates generally to construction of a reflector lamp unit, and more particularly to structural modification for compact reflector lamp units to enable installation in already existing socket fixtures.

[0002] Parabolic aluminized reflector (PAR) lamps, and less efficient lamps as regards quality of beam control, as represented by reflector (R) lamps, are already known for general spot or floodlighting applications. The originally designed PAR and some R lamps had relatively large physical dimensions when compared to common incandescent lamps. The requirement for installation of said lamps into relatively large socket fixtures limited their application particularly for indoor installation. Accordingly, subsequent PAR and R lamp designs has reduced overall dimensions while still main­taining the precise efficient beam control so as to increase their utilization for indoor applications.

[0003] In order to promote a still greater utilization of such more compact reflector lamp constructions, it becomes equally desirable that lamps be installed in existing socket fixtures of the customer. For example, installation of a compact PAR 30 lamp commonly requires such lamp to meet the spatial requirements for the US "R30ANSI Box" standard, which dictates both maximum and minimum lamp space to the fixture manufacturer. Compliance by the lamp manufacturer with such requirements for the reflector lamp unit being installed is understandably desirable so that neither customers nor fixture manufacturers are required to adjust their practices. While simply increas­ing the manufactured length of the lamp member for such lamp unit can satisfy the aforementioned installation requirements, such procedure proves impractical for a number of important considerations including increased lamp cost and specialized manufacturing equipment while still further requiring a pro­liferation of lamp parts. Moreover, lengthening the bottom neck portion of a reflector lamp member for compact PAR 30 lamp units now being manufactured gives rise to a further serious problem. Specifically, the aluminized reflecting surface being deposited in the extended neck portion of the lamp member is frequently non uniform to the extent of enabl­ing light escape thereat. Such light loss understandably proves unsightly when the installed lamp is being operated. Extending the overall length of a reflector lamp unit during manufacture by other means thereby proves desirable. It becomes further desirable to do so in a manner not requiring a structural modification of the lamp parts already being used or that the manufacturing procedure now being employed to assemble these lamp parts together be substantially altered. A known means whereby the reflector member in a reflector lamp unit is physically joined to a metal screw base with an interposed plastic skirt is disclosed in our U.S. Patent No. 4,658,178. While the over­all length of a reflector lamp unit can apparently be increas­ed in such manner, the disclosed means for doing so requires that the lamp parts being joined together have a modified con­struction while still further requiring modification in the customary manufacturing procedure. In the former regard, joinder between the plastic skirt and reflector member employs a complimentary engagement of finger elements provided in the skirt construction with dimples formed on the reflector mem­ber Joinder of the plastic skirt to the disclosed metal screw base includes a similar locking-type engagement between dim­ples formed in the metal base shell and indents provided the skirt member. The procedure disclosed for assembling such modified lamp parts together also departs significantly from conventional practice wherein the metal base shell is affixed to a reflector member with adhesive cement. As there­in disclosed, the plastic skirt is required to be screwed in­to the metal base shell thereby risking some deformation or mechanical failure of the lamp parts being joined together in such manner.

[0004] It is an object of the present invention, therefore, to provide an improved reflector lamp unit for installation in existing socket fixtures.

[0005] The present invention enables a still further size reduction of a compact reflector member to ameliorate the difficulties above pointed out in connection with conventional reflector lamp units of this type. As a structural modification it uses an electrically non-conduc­tive hollow sleeve adhesively bonded at one end to the bottom portion of the reflector member while being adhesively bonded at the opposite end to a hollow metal screw base of the reflector lamp unit. Generally, a reflector lamp unit having said modified construction includes: (a) a reflector having an internal electrically conductive reflective surface and a longitudinally extending bottom portion, (b) a tungsten-halo­gen lamp being positioned approximately at the optical focal point of the reflector which comprises an elongated sealed envelope of light transmissive material containing an inert gas fill and a halogen substance together with a tungsten filament being suspended therein by at least one pair of electrical conductors sealed at one end of the lamp envelope in a pinch seal region and protruding from the sealed envelope, (c) a hollow metal screw base affixed to the bottom portion of the reflector with an interposed electrically non-­conductive sleeve member having a hollow internal cavity and being provided at one end with an interior contour sized and shaped to accommodate insertion and physical support of the bottom reflector portion inserted thereinto while being pro­vided at the opposite end with an external contour sized to accommodate insertion of said opposite end into the hollow screw base, the sleeve member further being adhesively bonded to both bottom reflector portion and hollow screw base, (d) means for electrically connecting both protruding elec­trical conductors to the screw base, and (e) the hollow sleeve enabling the length of the reflector bottom portion to accommodate installation in existing socket fixtures, said accommodation avoiding any significant light escape thereat that might otherwise occur for a longer bottom portion of said reflector. A reflector lamp unit of this type generally further includes a lens element affixed at the top portion of the reflector. Various mounting structures to physically support the tungsten-halogen lamp being employ­ed in said improved reflector lamp unit are contemplated along with various structural modifications for such light source itself. For example, physical support of the tungsten-­halogen lamp can be provided entirely by the above defined protruding electrical conductors. A known lamp mount of this type connects opposite ends of the lamp filament to a first pair of refractory metal electrical conductors with the opposite ends of said refractory metal electrical conductors being further joined to a second pair of larger diameter electrical conductors exhibiting greater thermal expansion characteristics in the pinch seal region of the lamp envelope. Alternative lamp mount constructions employing but a single pair of refractory metal electrical conductors being connect­ed to the lamp filament are also known. It has previously been proposed, for instance in US application No. 331154, a copy of the specification and drawings of which is filed herewith for reference, that such latter type mount construction further include auxiliary clamp means provided in the pinch seal region of the lamp envelope to better withstand mechanical shocks and vibrations being experienced by the installed lamp. Suitable tungsten-halogen lamp constructions further include filament alignment being substantially along the central or longitudinal lamp unit axis as well as being substantially transverse thereto. In a still further contemplated modification of the present reflector lamp unit, the longitudinally extending bottom portion of the reflector terminates in at least one pair of openings extending therethrough and a pair of electrically conductive post members extending through said openings for connection to the pair of protruding electrical conductors. For said lamp embodiment, the outermost end of both post members can terminate within the internal cavity of the hollow sleeve so as to be electrically connected thereat to additional electrical conductors emerging from opposite end locations of the hollow sleeve which are electrically con­nected to the screw base.

[0006] In one preferred embodiment, the present reflector lamp unit comprises: (a) a pressed glass concave reflector having a parabolic shaped internal electrically conductive reflective surface and a longitudinally extending conical shaped bottom portion, the bottom portion further terminating in at least one pair of openings extending therethrough, (b) a tungsten-halogen lamp which includes a coiled tungsten filament being positioned approximately at the optical focal point of the reflector, the tungsten-halogen lamp further including an elongated sealed aluminosilicate glass envelope which contains a fill at superatmospheric pressure of at least one rare gas and a vaporizable halogen compound, and the tungsten filament coil being suspended at opposite ends from at least one pair of electrical conductors sealed at one end of the glass envelope in a pinch seal region and pro­truding from the sealed envelope, (c) an electrically non-­conductive sleeve member having a hollow cavity and physically securing the reflector bottom portion to a hollow metal screw base, the sleeve member having an interior contour at one end sized and shaped to accommodate insertion and physical sup­port of the reflector bottom portion inserted thereinto while having an external contour at the opposite end sized to accommodate insertion of the opposite end into the hollow screw base, the sleeve member further being adhesively bonded to both bottom reflector portion and hollow screw base, (d) means for electrically connecting both protruding elec­ trical conductors to the screw base, such means including one pair of electrically conductive post members extending through the reflector openings and connected to said pair of electrical conductors, (e) means for securing the post mem­bers in said openings with an electrically non-conductive adhesive together with barrier means preventing the adhesive from entering the internal reflector cavity, and (f) the hollow sleeve enabling the length of the reflector bottom portion to accommodate installation in existing socket fixtures, said accommodation avoiding any significant light loss thereat that might otherwise occur for a longer bottom portion of said reflector. Both openings for the post mem­bers in the lamp embodiment can be provided with an elec­trically non-conductive wafer that is joined to the reflector bottom portion at its terminal end with a ceramic cement. Conductor means for electrically connecting the protruding electrical conductors in said embodiment can further include a fuse element while the hollow sleeve in said lamp embodi­ment can have channel means accommodating one of the protrud­ing electrical conductors. Modification of the parabolic reflector cavity to provide a concave elliptical contour is also contemplated.

[0007] In the accompanying drawings:

FIG. 1 is a side view illustrating one embodiment of a compact parabolic aluminized reflector (PAR) type lamp unit according to the present invention.

FIG. 2(a) is a side view depicting one embodiment for the hollow cylindrical sleeve member employed in the reflector lamp of FIG. 1.

FIG. 2(b) is a top view of the sleeve member depicted in FIC. 2(a).

[0008] Referring to the drawings, there is depicted in FlG. 1 an improved reflector lamp unit 10 having a PAR 30 size configuration in accordance with one embodiment of the present invention. The lamp unit 10 includes a reflector 12 secured to a screw base 14 in the manner hereinafter defined and a tungsten-halogen lamp 16. The reflector 12 has an internal reflective parabolic surface 18 which may be typi­cally a silver, aluminum or dichroic type and a bottom por­tion 20 having a longitudinally extending conical configura­tion as shown. Bottom 20 of the reflector 12 is secured to the top end of a hollow non-conductive sleeve 22 which has a cylindrical shape while the bottom end of said sleeve 22 is similarly secured to screw base 14. As can also be seen in the drawing, bottom portion 20 of reflector 12 further in­cludes a pair of openings 24 and 26 provided with elec­trically non-conductive refractory type closure mean 28 which are secured to a central opening 29 terminating the lower end of said bottom portion 20. Reflector cavity 30 is fur­thur closed at its top end with a conventional lens element 32. Physical joinder of reflector 12 to base 14 by adhesive bonding to intervening sleeve 22 enables the reflector bottom portion 20 to be materially shortened in length while essen­tially preserving the overall lamp unit length for mounting in existing R30 socket fixtures. For example a one-half-­inch (12.7 mm) shorter reflector bottom portion can now be employed for the particular lamp unit being described.

[0009] Tungsten-halogen lamp 16 includes an axially aligned tungsten coil filament 31 hermetically sealed within an elongated lamp envelope 33 so as to have the center of the tungsten coil reside approximately at the optical focal point of reflector 12. Filament coil 31 is physically suspended within lamp envelope 33 by a composite assembly of "lead wire" type electrical conductors 34, 36, 30 and 40. More particularly, such cooperating lead wire construction employs a first pair of electrical conductors 34 and 36 con­nected at one end to the lamp filament coil 31 while being individually connected at the opposite ends to larger dia­ meter electrical conductors 38 and 40 in the stem press region 42 of the lamp envelope 33. For the particular size lamp embodiment being illustrated, suitable inner elec­trical conductors 34 and 36 can be formed with approximately 12-30 mils diameter molybdenum alloy, whereas suitable pro­truding electrical conductors 38 and 40 can be formed with an electrically conductive metal having greater thermal expansion characteristics, such as nickel plated iron or nickel iron alloy, at approximately 35-60 mils diameter. In other lamp embodiments, a single pair of molybdenum alloy electrical conductors having a diameter up to about 25 mils can provide suitable suspension of the lamp envelope when utilized in combination with the external clamp support means disclosed in the referenced U.S. No. 331 154 application. The depicted lamp envelope 33 further includes a gaseous fill (not shown) which includes at least one rare gas and a vaporizable halogen substance such as an alkyl halide.

[0010] Protruding electrical conductors 38 and 40 in the depicted lamp unit embodiment can be seen to extend through openings 24 and 26, respectively, provided with electrically non-conductive refractory closure means 28. As depicted in the drawing, suitable refractory closure means 28 includes a glass or ceramic wafer 35 adhesively bonded to the terminal reflector opening 29 with an electrically non-conductive refractory cement 37. Said conductors are also secured in the wafer openings with said thermally resistant electrically non-conductive cement while further refractory barrier means 43 prevent said adhesive material from entering the internal reflector cavity. Means are provided to electrically connect the protruding lower ends of said electrical conductors to the conventional type screw base 14 within the central cavity of hollow sleeve 22. More particularly, such electrical interconnection of protruding conductor 38 to the side of metal base 14 is provided with a conductor 44 whereas remain­ing protruding conductor 40 is interconnected to a center eyelet 46 of said metal base shell with a conductor 47. The desired interconnection can be provided by conventional metal fastening means such as soldering, welding or staking, and it is contemplated that the parameters selected for conduc­tor 47 can serve as a fuse element. While not shown in the depicted lamp unit embodiment, it becomes further possible to modify the compact reflector lamp unit disclosed in the above referenced U.S. No. 331 154 application so as to employ a structural configuration according to the present invention. It can be appreciated that such a modification simply entails interposition and physical joinder, such as with an adhesive cement, of the sleeve member 22 between the reflector and screw base members therein employed. It will also be apparent that such a lamp unit modification would also now employ a pair of post elements which extend upward­ly through the openings provided in the bottom section of the reflector member and with said post members being con­nected to the pair of electrical conductors protruding from one end of the suspended tungsten-halogen lamp.

[0011] As can further be noted in the drawing for a typical lamp unit according to the present invention after final assembly, sleeve member 22 has a particular structural configuration (to be more fully explained in connection with related FIGS. 2(a) and 2(b)) which enhances automated assembly of the lamp parts. More particularly, an upper tapered portion 48 of the hollow sleeve member enables reflector bottom por­tion 20 to be fitted thereinto for joinder together with con­ventional adhesive means whereas a cylindrical lower portion 50 of said sleeve enables its insertion into the hollow screw base 14 for similar joinder thereto. Additional surface relief features are further provided enabling these lamp components to cooperate when being joined together. A ledge or shoulder 52 located at the midsection of sleeve 22 enables seating of said member in the hollow base shell during the assembly procedure. A groove or channel 54 is further pro­ vided on the outer surface of said sleeve member for insertion of conductor 44 thereinto. A still further protuberance or rib element 56 is located on the interior surface of said sleeve member for alignment and retention of said member to the reflector bottom portion when being assembled together. In doing so, said rib element physically interfaces with a suitable located groove or depression 21 on the exterior surface of the reflector bottom portion.

[0012] FIG. 2(a) is a side view of the hollow cylindrical sleeve member 22 employed in the FIG. 1 reflector lamp unit whereas FIG. 2(b) is a top view of the same sleeve member. Such sleeve member can readily be formed with a thermally resistant synthetic organic polymer material, such as poly­phenylene sulfide or liquid crystal polymer, in order to resist wall temperatures of 200°C and higher when the depicted lamp unit is being operated. As previously described, a sleeve member formed in said manner provides an upper tapered portion 48 (as shown in FIG. 2(a) joined to lower cylindrical portion 50 at a midsection shoulder or ledge 52. The interior contour of the upper tapered portion 48 is sized to accommodate insertion of the bottom reflector portion 20 thereinto for joinder together and which is further enhanced with an inner projection 53 being provided to physically support the inserted reflector member. The external contour of lower cylindrical portion 50 is sized to accommodate its insertion into the hollow cavity provided in the metal base shell 14 with the outwardly protruding shoulder 52 extending therefrom structurally supporting the assembled configuration. A central opening or cavity 55 extends the entire length of the depicted sleeve member to enable passage of the conductor means being selected to electrically interconnect the tungsten-­halogen lamp in the reflector unit to the metal base shell. The channel or groove 54 (as shown in FIG. 2(b)) further provided on the exterior contour of lower cylindrical portion 50 enables one conductor 44 selected for this purpose to be inserted thereinto for terminal connection to the side of the metal base shell. The rib element 56 of FIG. 2(b) protruding from the inner contour of upper tapered 48 is pro­vided to register with a mating surface relief feature pro­vided on the exterior surface of the reflector bottom por­tion and thereby help to align and retain said lamp parts together during the assembly procedure.

[0013] Fully automated manufacture of the above illus­trated reflector lamp unit can be carried out with conven­tional lamp assembly equipment. In doing so, the tungsten-­halogen lamp 16 and reflector member 12 are first assembled together in the customary manner. Conductors 44 and 46 are next secured to the protruding lamp conductors 38 and 40 by such conventional means as soldering or welding. Sleeve 22 is then joined to the bottom portion 20 of the reflector member such as with a suitable epoxy cement. Screw base 14 is next joined to the opposite end of sleeve 22 in the same or similar manner and final electrical connection of conduc­tors 44 and 46 is made to said base member again in the con­ventional manner. Such lamp unit can now be installed in existing socket fixtures.

[0014] It will be apparent from the foregoing description that a generally improved compact reflector lamp unit has been provided which can be installed without further modifi­cation in existing socket fixtures and permits relatively convenient installation as well as removal of the unit by the user. The described construction, which lessens the chance of light projection other than in the forward direction, can be assembled on existing automated manufacturing equipment without requiring significant equipment modification.

[0015] It is contemplated that modifications can be made in the lamp embodiments herein illustrated without departing from the scope of the present invention. For example, while the invention has been described, in an important application thereof, in the context of reflector lamp units incorporating tungsten-halogen lamps, it may also find application in such units incorporating other light sources capable of being similarly mounted with the reflector. Furthermore the sleeve member construction can employ other electrically non-conductive materials including glass and ceramics. Likewise, the parabolic reflecting surface of the reflector member herein illustrated can be provided with other already known contours while the reflective surface can be provided with stippling or a diffuse reflective coating as well as other known multi-faceted reflective configurations. Similarly, the present tungsten-halogen lamp construction can include various tungsten filaments, sized and shaped for the particular wattage and voltage requirements of the intended lamp unit applications. Moreover, already known thermal shield means can also be included in the present lamp construction.

Claims

1. A reflector lamp unit comprising:

(a) a reflector having an internal electrically conductive reflective surface and a longitudinally extending bottom portion,

(b) a light source positioned approximately at the optical focal point of the reflector and having at least one pair of electric conductors protruding from said source,

(c) a sleeve member having a hollow internal cavity and being provided with an interior contour at one end sized and shaped to accommodate insertion and physical support of the bottom reflector portion inserted thereinto while being provided at the opposite end with an external contour sized to accommodate insertion of said opposite end into a hollow screw base, the sleeve member further being adhesively bonded to both bottom reflector portion and hollow screw base,

(d) means for electrically connecting both pro­truding electrical conductors to the screw base, and

(e) the sleeve member enabling the length of the reflector bottom portion to accommodate installation in existing socket fixtures, said accommodation avoiding any significant light escape that might otherwise occur for a longer bottom portion of said reflector.

2. A reflector lamp unit according to claim 1 wherein physical support of the light source is provided entirely by the protruding electrical conductors.

3. A reflector lamp unit according to claim 1 or 2 wherein the longitudinally extending bottom portion of the reflector terminates in at least one pair of openings extending therethrough and a pair of electrically conductive post members extending through the openings for connection to the pair of electrical conductors.

4. A reflector lamp unit according to claim 3 wherein the outermost end of both post members terminate within the internal cavity of the hollow sleeve and are electrically connected thereat to additional electrical conductors emerging at opposite end locations of the hollow sleeve for electrical connection to the screw base.

5. A reflector lamp unit according to claim 3 or 4 wherein the top portion of the post openings is devoid of an electrically conductive reflective surface.

6. A reflector lamp unit according to claim 3, 4 or 5 wherein the post members are secured in the openings with an electrically non-conductive adhesive material and barrier means are provided to prevent the adhesive from entering the internal reflector cavity.

7. A reflector lamp unit according to any of claims 1 - 6 where the bottom portion of the reflector and hollow sleeve are provided with cooperating surface relief means to help in being affixed and aligned together.

8. A reflector lamp unit according to any of claims 1 - 7 wherein the sleeve member is formed with a thermally resistant synthetic organic polymer material.

9. A reflector lamp unit according to any of claims 1 - 8 wherein the sleeve member includes a groove accommodating passage of the means for electrically connecting the protruding electrical conductors to the screw base.

10. A reflector lamp unit according to any of claims 1 -9 wherein said light source is a tungsten-halogen lamp which comprises an elongated sealed envelope of light transmissive material containing an inert gas fill and a halogen substance together with a tungsten filament being suspended therein from said at least one pair of electrical conductors sealed at one end of the lamp envelope in a pinch seal region and protruding from the sealed envelope.

11. A reflector lamp unit according to claim 10 wherein the tungsten filament is connected at opposite ends to a single pair of refractory metal electrical conductors hermetically sealed at tne pinch seal region of the lamp envelope.

12. A reflector lamp unit according to claim 10 wherein the tungsten filament is connected at opposite ends to a first pair of refractory metal electrical conductors with the opposite end of the refractory metal electrical conductors being further joined to a second pair of larger diameter electrical conductors exhibiting greater thermal expansion characteristics.

13. A reflector lamp unit according to claim 10, 11 or 12 wherein the tungsten filament is axially aligned substantially along the central lamp unit axis.

14. A reflector lamp unit comprising:

(a) a reflector being pressed glass and having a parabolic shaped internal electrically conductive reflective surface which terminates in a longitudinally extending conically shaped bottom portion having a pair of openings extending therethrough,

(c) an electrically non-conductive sleeve member having a hollow internal cavity and being provided with an interior contour at one end sized and shaped to accommodate insertion and physical support of the bottom reflector por­tion inserted thereinto while being provided at the opposite end with an external contour sized to accommodate insertion of said opposite end into a hollow screw base, the sleeve member further being adhesively bonded to both bottom reflec­tor portion and hollow screw base,

(d) means for electrically connecting both protrud­ing electrical conductors to the screw base being located within the internal cavity of the hollow sleeve, such means including at least one pair of electrically conductive post members extending through the reflector openings and con­nected to said pair of electrical conductors,

(e) means for securing the post members in said openings with an electrically non-conductive adhesive together with barrier means preventing the adhesive from entering the internal reflector cavity, and

(f) the hollow sleeve enabling the length of the reflector bottom portion to accommodate installation in existing socket fixtures, such accommodation avoiding any significant light loss thereat that might otherwise occur for a longer bottom portion of said reflector.

15. A reflector lamp unit according to claim 14 wherein physical support of the light source is provided entirely by the protruding electrical conductors.

16. A reflector lamp unit according to claim 14 or 15 wherein the openings for the post members are provided with an electrically non-conductive wafer that is sealed to the reflector bottom portion at its terminal end.

17. A reflector lamp unit according to claim 14, 15 or 16 where the means for electrically connecting the protruding electrical conductors further includes a fuse element.

18. A reflector lamp unit according to any of claims 14 - 17 wherein the hollow sleeve further includes an external surface channel accommodating one of the protruding electrical conductors.

19. A reflector lamp according to any of claims 14 - 18 wherein said light source is a tungsten-­halogen lamp which includes a coiled tungsten filament being positioned approximately at the optical focal point of the reflector, the tungsten-halogen lamp further including an elongated sealed aluminosilicate glass envelope which contains a fill at superatmospheric pressure of at least one rare gas and a vaporizable halogen compound, and the tungsten filament coil being suspended at opposite ends from said at least one pair of electrical conductors sealed at one end of the glass envelope in a pinch seal region and protruding from the sealed envelope.

20. A reflector lamp unit according to claim 19 wherein the tungsten filament is axially aligned substan­tially along the central lamp unit axis and connected at opposite ends to a single pair of refractory metal electrical conductors hermetically sealed at the pinch seal region of the glass envelope.

21. A reflector lamp unit according to claim 19 wherein the tungsten filament is axially aligned substan­tially along the central lamp unit axis and connected at opposite ends to a first pair of refractory metal electrical conductors with the opposite end of the refractory metal electrical conductor being further joined to a second pair of larger diameter electrical conductors exhibiting greater thermal expansion characteristics.

22. A reflector lamp unit according to any preceding claim further including a lens element affixed to the top portion of the reflector.

Drawing