Abstract:
A lighting system has a power source and a light head including a high intensity discharge lamp. The lamp is supported by a support base on a sealed electronics container that includes walls defining a space within which an electronic ballast is enclosed in proximity to the lamp to insure reliable ignition. A cover surrounding the lamp and sealed to the support base includes a portion allowing light to project outwardly from the light head. Thermally conductive material surrounds and contacts the electronic ballast and also the interior of the walls of the container so that the container extracts heat away from the ballast to the walls of the container.

Description:
This continuation application claims the benefit under 35 U.S.C. §120 of non-provisional application Ser. No. 10/745,139 filed Dec. 23, 2003 (the &#39;139 application has been allowed and the issue fee paid) which claims the benefit under 35 U.S.C. §120 of non-provisional application Ser. No. 09/783,767 filed Feb. 15, 2001, now U.S. Pat. No. 6,679,619 (currently under inter partes reexamination—see Inter Partes Reexamination Control No. 95/000,060), which claims the benefit of provisional application Ser. No. 60/183,767, filed Feb. 18, 2000, the complete disclosures of which are incorporated by reference herein. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to lamps and lighting systems and, more particularly, to an HID lamp with integral ballast and lighting systems incorporating the same. While the present invention will be described with reference to underwater diving light systems for which it was originally developed, it is to be understood that it can be used for other lighting applications both in and out of water. 
   2. Brief Description of the Prior Art 
   Underwater exploration, or exploration in other low ambient light environments, is virtually impossible without the aid of some type of artificial lighting system. Even under broad daylight, when diving beyond a certain depth, the natural light from the sun is severely affected by the water. In addition to loss of light intensity, water produces spectral changes in the light to the extent that color is not readily recognizable and the view underwater appears to be only bluish black and white. Moreover, even at relatively shallow depths, artificial lighting is necessary to see objects in shadows or in crevices. Exploration of caves, shipwrecks, or comparable very dark or harsh environments, is impossible without bright artificial lighting systems. 
   The simplest lighting systems utilize ordinary incandescent lamps powered by rechargeable batteries. Ordinary incandescent lamps are inefficient and produce a limited spectrum which is unsuitable for photography, particularly under water. Halogen lamps provide a much higher intensity than ordinary incandescent lamps and also provide a balanced spectrum which can be used with certain types of film to capture colors accurately in difficult lighting conditions, such as underwater. For example, many halogen lamps are balanced to a color temperature of 3200° K, and some film emulsions are designed to be used with illumination within this spectrum. Filters are also available for use with daylight (6500° K) balanced emulsions and 3200° K light sources. 
   Although the halogen lamps are an improvement over ordinary incandescent lamps, they share some of the disadvantages of ordinary incandescent lamps and have some disadvantages of their own. Both incandescent and halogen lamps rely on the heating of a filament by an electric current passing through the filament. In order to produce more light output and a higher color temperature, more current must be provided to the filament and that requires either a larger battery or results in a shorter “burn life”. Since divers and explorers are burdened with enough equipment to begin with, a large battery pack is certainly undesirable. Filament lamps also have the disadvantage that the filament is easily damaged by thermal or mechanical shock. 
   A relatively new type of lamp referred to as a high intensity discharge (HID) lamp is disclosed in U.S. Pat. No. 5,144,201 (the complete disclosure of which is hereby incorporated by reference herein) and is commercially available, for example from Welch Allyn, Inc. (Skaneateles Falls, N.Y.). The HID lamp contains an anode and a cathode and a mixture of mercury, argon and other chemicals. The anode and the cathode are coupled to a ballast having a DC power input. When a DC voltage (typically 9-16 VDC) is applied to the power input of the ballast, the ballast begins a start up sequence. The ballast first produces a series of high voltage (such as 25 KV) high frequency (such as 33 KHZ) pulses that ionize the gases inside the lamp. During this sequence the ballast monitors the resistance of the lamp. When the gases have been sufficiently excited, an arc is struck across the anode and cathode. After the arc is struck, the ballast applies a reduced DC voltage to the anode and cathode of approximately 60 VDC. The ballast continuously monitors the resistance of the lamp and controls the current to the lamp in order to maintain the arc and prevent overdriving, see U.S. Pat. No. 5,381,076 (the complete disclosure of which is hereby incorporated by reference herein). The color of the light produced by the HID lamp is determined by the mix of material (compounds and/or gases) contained in the lamp and the extent to which they are excited by the continuing current. Typically, the desired color temperature is in the range of 4700° K-6500° K. 
   The HID lamps sold by Welch Allyn and others are not particularly designed for underwater use. Many manufacturers of these lamps intend them to be used in automotive applications and in image projection applications such as projection television. For a variety of reasons, Welch Allyn recommends that the lamp and ballast be located apart from each other. In most applications, this does not present a problem. However, in an underwater lighting system, location of the ballast apart from the lamp can be problematic. The typical underwater lighting system includes a battery pack which is coupled by a cable to a lamp assembly which may be hand held in smaller sizes of lighting systems. If the ballast is not located adjacent to the lamp assembly, it must be located adjacent to the battery pack. The battery pack is typically strapped to the diver&#39;s torso, arm or leg. In order for the lamp assembly to be freely positionable, the cable connecting the lamp assembly to the battery pack must be sufficiently long. It has been discovered, however, that if the cable length from the ballast to the lamp assembly is more than approximately 18 inches, the lamp may not reliably start up. 
   SUMMARY OF THE INVENTION 
   In accordance with one aspect of the present invention, a high intensity discharge lamp assembly comprises a high intensity discharge lamp having a hermetically sealed glass envelope containing a mixture of ionizable elements and/or compounds and a sealed ballast container including a support base adapted to receive and support the lamp. An electronic ballast within the container has an input and an output. An anode disposed in the envelope is electrically coupled to one pole of the ballast output and a cathode disposed in the envelope is electrically coupled to another pole of the ballast output. Coupling means connect the input of the ballast to a DC power pack, the coupling means comprising wet mateable connectors for switching of DC power packs while underwater. Heat sink means including the ballast container extract heat from the ballast and transfer the extracted heat to an exterior of the ballast container. A waterproof protective cover covers the envelope, is sealed to the support base and has a portion for transmitting light from the lamp. 
   In accordance with another aspect of the present invention, a high intensity discharge lamp assembly comprises a high intensity discharge lamp having a hermetically sealed glass envelope containing a mixture of ionizable elements and/or compounds and a sealed ballast container mounted adjacent to the glass envelope. An electronic ballast having an input and an output is contained in the container. An anode disposed in the envelope is electrically coupled to one pole of the ballast output and a cathode disposed in the envelope is electrically coupled to another pole of the ballast output. Coupling means connects the input of the ballast to a DC power pack and includes wet mateable connectors for switching DC power packs while underwater. Heat sink means including the ballast container extract heat from the ballast and transfer the extracted heat to an exterior of the ballast container. A waterproof protective cover covers the lamp envelope, is sealingly coupled to the ballast container and has a portion for emission of light outside the lamp assembly. 
   In accordance with still another aspect of the present invention, a high intensity discharge lamp assembly comprises a high intensity discharge lamp having a hermetically sealed glass envelope containing a mixture of ionizable elements and/or compounds. A sealed ballast container is mounted adjacent to the lamp, is filled with a material and serves as heat sink means. An electronic ballast is contained in the container and has an input and an output with the heat sink means extracting heat from the ballast to an exterior of the ballast container. An anode disposed in the envelope is electrically coupled to one pole of the ballast output and a cathode disposed in the envelope is electrically coupled to another pole of the ballast output. Coupling means couple the input of the ballast to a DC power source and a waterproof protective cover covers the envelope and has a light transmitting portion. 
   In accordance with an additional aspect of the present invention, an underwater lighting system comprises a high intensity discharge lamp having a hermetically sealed glass envelope containing a mixture of ionizable elements and/or compounds and a sealed ballast container mounted adjacent to the glass envelope. An electronic ballast contained in the ballast container has an input and an output. The ballast container is substantially filled with a thermally conductive material to eliminate vacant spaces withing the container so that the ballast container extracts heat away from the ballast. An anode disposed in the envelope is electrically coupled to one pole of the ballast output and a cathode disposed in the envelope is electrically coupled to another pole of the ballast output. Coupling means couple the input of the ballast to a DC power source. A waterproof protective cover covers the lamp and has a portion for transmitting light from the lamp. 
   In accordance with yet another aspect of the invention, a lighting system comprises a light head and a power source, the light head including a high intensity discharge lamp having a sealed glass envelope containing a mixture of ionizable elements and/or compounds. A sealed electronics container comprises walls surrounding and enclosing a space and having a support base thereon supporting the lamp. A cover surrounds the lamp, is sealed to the support base and includes a portion allowing light to project outwardly from the light head. An electronic ballast enclosed within the space of the container is in proximity to the lamp to insure reliable ignition. A quantity of thermally conductive material surrounding and in contact with the electronic ballast and also an interior of the walls of the container so that the container extracts heat away from the ballast to the walls of the electronics container. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevation view of a first embodiment of a lamp and ballast assembly according to the invention; 
       FIG. 1   a  is an end view of the lamp and ballast assembly of  FIG. 1 ; 
       FIG. 1   b  is a schematic representation of the lamp and ballast assembly of  FIG. 1   a.    
       FIG. 2  is a side elevation view of a second embodiment of a lamp and ballast assembly according to the invention; 
       FIG. 2   a  is an end view of the lamp and ballast assembly of  FIG. 2 ; 
       FIG. 3  is a side elevation view of a third embodiment of a lamp and ballast assembly according to the invention; 
       FIG. 3   a  is an end view of the lamp and ballast assembly of  FIG. 3 ; 
       FIG. 4  is a side elevation view of a fourth embodiment of a lamp and ballast assembly according to the invention; 
       FIG. 4   a  is an end view of the lamp and ballast assembly of  FIG. 4 ; 
       FIG. 5  is a side elevation view of a fifth embodiment of a lamp and ballast assembly according to the invention; 
       FIG. 5   a  is an end view of the lamp and ballast assembly of  FIG. 5 ; 
       FIG. 6  is a side elevation view of a sixth embodiment of a lamp and ballast assembly according to the invention; 
       FIG. 6   a  is an end view of the lamp and ballast assembly of  FIG. 6 ; 
       FIG. 7  is a side elevation view of a first embodiment of a cable connector; 
       FIG. 8  is a side elevation view of a second embodiment of a cable connector; 
       FIG. 9  is a side elevation view of a socket for use with the cable connector of  FIG. 8 ; 
       FIG. 9   a  is an end view of the socket of  FIG. 9 ; 
       FIG. 10  is a perspective view of a lighting system according to the invention; 
       FIG. 11  is a side elevation view of a seventh embodiment of the invention showing a hand-held unit composed of a lamp ballast and battery; 
       FIG. 11   a  is an end view of the invention shown in  FIG. 11 ; 
       FIG. 12  is a side elevation view of an eighth embodiment of the invention in the form of a head-mount or hand-held unit composed of a lamp and ballast; and 
       FIG. 12   a  is an end view of the unit shown in  FIG. 12 . 
   

   DETAILED DESCRIPTION 
   Turning now to  FIGS. 1 ,  1   a  and  1   b , a lamp and ballast assembly  10  according to the invention includes a lamp L having an hermetically sealed quartz glass envelope  12  containing an anode  14 , a cathode  16 , and a mixture of ionizable elements and/or compounds (not shown) such as disclosed in referenced U.S. Pat. No. 5,144,201. A sealed, thermally conductive ballast container  18  located adjacent to the glass envelope  12  of the lamp L includes a lamp support base or lamp support  11  adapted to receive and support the lamp L. As shown in  FIG. 1   b , an electronic ballast  13  (schematically illustrated) having an input  20  and an output  15 , is located in the sealed container  18 . The output  15  is electrically coupled to the anode  14  and cathode  16  via separate high voltage output poles  17 ,  19 , respectively, through a lamp holder defined by the lamp support  11  which incorporates the high voltage output poles  17 ,  19 . A glass outer tubular waterproof protective cover  11   a  surrounds the quartz glass envelope  12  and extends around the end of the lamp support  11 . A portion of the cover  11   a  can serve as a transparent window for transmitting light from the lamp outside the lamp and ballast assembly  10 . The waterproof protective cover  11   a  is held in place by O-ring seals  11   b  which also seal the cover  11   a  to the support  11 . The ballast container  18 , made of metal, plastic or any combination of metal and plastic, is located in close proximity to the quartz envelope  12  of the lamp L and is waterproof and pressure proof so that the ballast container  18  in cooperation with the cover  11   a  provide a waterproof exterior for the lamp and ballast assembly  10 . 
   The container  18  can have mechanically pressure resistant walls, or preferably, is filled and sealed tightly by being filled or potted with a thermally conductive (electrically-non conductive) insulator material. This material, such as an epoxy insulator  21 , extends at least from the juncture of the lamp support  11  and the container  18  (see  FIG. 1   b ) and fills the interior of the container  18  around the ballast  13  and any related electronics to eliminate vacant spaces within the container  18 . This material also serves to extract heat away from the ballast  13  so that the ballast container and the material serve as heat sink means. The ballast container  18  can be in the nature of a mold which, once the potting epoxy has solidified, may optionally be removed. The potted, thermally conductive, electrically non-conductive insulator mass  21  surrounds, or substantially surrounds, the ballast  13  and any related electronic components and extends rearward, e.g., to the right in  FIG. 1 , from the lamp support  11  and along the ballast input  20 . 
   The ballast input  20  is preferably coupled to a standard type of connector (see  FIG. 7  and  FIG. 8  described below) so that the lamp and ballast assembly  10  may be retro-fitted to an existing lighting system or a DC power source  901  via coupling means or cable  902  (see  FIG. 10 ). As shown in  FIG. 1 , a portion of the connector (otherwise not shown) includes a strain relief  22 . As shown in  FIGS. 1   a  and  1   b , the ballast container  18  is rectangular in configuration and surrounds the ballast  13  with a layer of the thermally conductive potting material  21 . According to this embodiment, the lamp and ballast assembly  10  is a 10-30 watt lamp, has an overall length of about 8 3/16 inches, and a maximum width of about 2 3/16 inches. 
   Turning now to  FIGS. 2 and 2   a , a lamp and ballast assembly  110  according to the invention is similar to the lamp and ballast assembly  10  described above with similar reference numerals referring to similar features. According to this embodiment, the lamp and ballast assembly  110  includes a 10-30 watt lamp, has an overall length of about 6 1/16 inches and a maximum width of about 3 3/16 inches. 
   Turning now to  FIGS. 3 and 3   a , a lamp and ballast assembly  210  according to the invention is similar to the lamp and ballast assembly  10  described above with similar reference numerals referring to similar features. According to this embodiment, the glass envelope  212  is contained within a cylindrical protector  224  having a transparent or otherwise light transmitting portion illustrated as a window  226  and the ballast container  218  is also cylindrical. The lamp and ballast assembly  210  includes a 10-30 watt lamp, has an overall length of about 5 inches and a maximum diameter of about 2⅜ inches. 
   Turning now to  FIGS. 4 and 4   a , a lamp and ballast assembly  310  according to the invention is similar to the lamp and ballast assembly  210  described above with similar reference numerals referring to similar features. According to this embodiment, the ballast container  318  is rectangular. The lamp and ballast assembly  310  includes a 10-30 watt lamp, has an overall length of about 5 inches and a maximum width of about 3 3/16 inches. 
     FIGS. 5 and 5   a  illustrate a lamp and ballast assembly  410  which is housed in a monolithic cylinder  418  having a transparent window  426  at one end and a strain reliever  422  at its opposite end. The lamp and ballast assembly  410  includes a 10-30 watt lamp, has an overall length of about 5 5/18 inches and a maximum diameter of about 2½ inches. The monolithic cylinder is preferably hermetically sealed and waterproof to a predetermined depth. 
     FIGS. 6 and 6   a  illustrate a lamp and ballast assembly  510  which is similar to the lamp and ballast assemblies  10  and  110  described above. The lamp and ballast assembly  510  includes a 50-90 watt lamp, has an overall length of about 7.25 inches and a maximum width of about 5.187 inches. 
   Turning now to  FIG. 7 , a connector  600  according to the invention includes a cable  602  having free ends  604 ,  606  for relatively permanent coupling to a battery pack (not shown). The other end of the connector  600  has a strain relief  622  which is similar to the strain reliefs describe above. 
     FIG. 8  illustrates an alternate connector  700 , which includes a cable  702  having a male/female connector  703  with a male contact  704  and a female contact  706  at one end thereof and a strain relief  722  at the other end thereof. The connector  700  is designed to be temporarily connected to a battery pack and swappable to another battery pack while under water (“wet pluggable” or “wet mateable”) using a mating connector from the battery/power pack (not shown). 
     FIGS. 9 &amp; 9A  illustrate an alternate connection  800  which includes a male contact  804  and a female contact  806 . The connector  800  is designed to be temporarily connected to a battery pack and swappable to another battery pack while under water (“wet pluggable” or “wetmateable”) using a mating connector from the battery/power pack. 
     FIG. 10  illustrates a lighting system  900  according to the invention. The system  900  includes a battery pack  901  and a lamp and ballast assembly  910 . The ballast in the lamp and ballast assembly  910  is coupled by a cable  902 , having a connector  903  and a strain relief  922 , to the battery pack  901 . The assembly  910  is hermetically sealed and waterproof to a predetermined depth. 
     FIGS. 11 and 11   a  illustrate a hand-held lamp and ballast assembly  810  which is similar to lamp and ballast assemblies  10 ,  110 ,  510  described above. The lamp and ballast assembly  810  is composed of a 10-20 Watt HID lamp and reflector assembly  812  which is coupled to a ballast and battery pack contained in housing  814  which is provided with a handle grip  816 . The assembly has an overall length of 5″ to 12″ and a width or diameter from 2″ to 6″. Both dimensions will be dependent on the battery chemistry and size used. 
     FIGS. 12 and 12   a  illustrate a mini lamp and ballast assembly  911  which is similar to lamp and ballast assemblies  10 ,  110 , and  510  described above. The lamp and ballast assembly  911  is composed of a 10-20 watt HID lamp and reflector assembly  912  which is coupled to a ballast contained in ballast housing  914  which, in turn, is provided with a connector  916  and a strain relief  918  to permit coupling to a remote battery pack (not shown). The lamp and ballast assembly  911  has an overall length of about 3¼″. The lamp and ballast assembly  911  is provided with a recessed center section  915  to allow the same to be releasably attached to a head clamp (not shown). Alternatively, it could be hand held. 
   There have been described and illustrated herein several embodiments of a high intensity discharge (HID) lamp with integral ballast used in underwater lighting systems incorporating the same. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as so claimed.