Abstract:
A lighting unit is provided including at least one LED, a plug for connecting the unit to an appliance and a light emitting element. The lighting unit may include electronic components to condition power from the appliance. The light emitting element may comprise a reflector where the LED emits light into the reflector and the light is collimated by the reflector and emitted from the unit. The position of the LED may be adjustable so the LED moves closer or farther from the reflector. Light is emitted from the unit in a narrower or wider beam in response to moving the LED. Alternately, the light emitting element may be an optical waveguide with a receiving end proximate to the LED emitting face and an emitting face away from and opposite the receiving face. The optical waveguide may collimate the wide angle of light emitted by the LED to form a narrow, directed beam.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to light units using light emitting diodes (LEDs) as the light source, which may be used to replace halogen, incandescent or fluorescent bulbs. 
       BACKGROUND OF THE INVENTION 
       [0002]    New high intensity LEDs have adequate light intensity and illumination to replace existing lighting, such as fluorescent, halogen and incandescent bulbs, while decreasing package size and power consumed. New high brightness LEDs use a more powerful chip to generate a much brighter light. Manufacturers are producing high brightness LED packages in a variety of forms. Originally these LEDs were directly substituted for standard incandescent bulbs. LEDs emit light from a plane rather than radiating omnidirectionally from an incandescent filament. The included angle of the light from an LED is much narrower than an incandescent bulb, but it is still not sufficiently narrow to form a beam, and the intensity of the light diminishes quickly with distance. 
         [0003]    Halogen, fluorescent and incandescent bulbs have used parabolic reflectors to direct and shape the light beam, and lenses to focus the beam. The conditioning of the emitted light was less complicated with sources such as incandescent bulbs, because the light source could be placed at the focal point of the parabolic reflector to get a focused beam. It is more difficult to get the apparent emitted light to appear at the focal point with a planar light source. LED units have employed a number of methods in order to use reflecting surfaces and focus a beam. One method reflects the LED light from a second mirror at the focal point into the focusing mirror. Yet another method uses a cylindrical reflector that directs the beam. 
         [0004]    Typically in light bulbs with directed or shaped beams, the intensity of the light in the beam is not uniform across the beam. This results in lighter and darker areas in the illuminated field. Some bulbs may also create a beam with an irregular shape. 
         [0005]    The optimal LED unit emits virtually all of the light from the LED into an optimally sized area with a fairly narrow angle. By so doing, light intensity and illumination are not diminished with distance from the viewer. The light should also be relatively uniform across the illuminated area. Optionally, it should be possible to adjust the width of the beam to meet a range of lighting requirements. 
       SUMMARY OF THE INVENTION 
       [0006]    A light emitting diode lighting unit is provided with a configuration, physical dimensions and performance characteristics that allow it to replace existing bulbs using less efficient light generation technologies. The unit may be configured to replace halogen, incandescent, fluorescent or other bulbs. The plug or connector may be sized to plug into a socket with a G4, G6.35, G8, G10 or other form factor socket. 
         [0007]    A first embodiment of a light emitting diode (LED) unit includes a near end and a distal end spaced apart and a central axis passing through the near end and distal end. The unit is configured to separably connect to an appliance with a socket. The LED unit includes a lamp housing, a plug at the near end with a plurality of exposed terminals configured to mate with the appliance socket, a reflector, substantially transverse to the central axis, configured to emit light at the distal end. The unit also includes an LED assembly oriented with the central axis, that has an LED with a luminescent front portion and operably connected to the plurality of exposed terminals, and an LED mount supporting the LED and orienting the LED to emit light into the reflector. The unit has at least one support with a near end and a distal end. The support is connected to the lamp housing at the near end and the LED assembly at the distal end. 
         [0008]    In a similar configuration of the first embodiment, an LED lighting system comprises an appliance that includes a socket and a lighting unit. The lighting unit includes a housing, a slidable LED, a curved reflector disposed opposite the LED for collimating light from the LED, a plug for mating to the appliance socket including terminals and a power supply for modifying power from the appliance. 
         [0009]    A second embodiment of an LED unit is configured to separably connect to an appliance at a socket. An example of the unit includes a housing supporting at least one LED having a luminescent front portion, a plug with a plurality of terminals configured to mate to the appliance socket and an optical waveguide with a near end and a distal end. The near end of the waveguide is positioned immediately adjacent the front portion of the at least one LED to at least partially collimate and reemit the light at the distal end. 
         [0010]    A similar configuration is an LED lighting system which includes an appliance with a socket and a lighting unit. The lighting unit includes a housing, an LED, a transparent light guide for collimating light emitted by the LED, a plug for mating to the appliance socket including terminals and a power supply for modifying power from the appliance. 
         [0011]    The LED unit power supply electronics condition or convert the power supplied at the appliance socket to a voltage and waveform compatible with the LED. Power conditioning may include rectifying the voltage from alternating cycle to a half-wave or direct current cycle and/or changing the voltage magnitude. For some configurations, no power supply electronics are required. 
         [0012]    The light guide or waveguide is formed of solid, transparent material having a first end positioned immediately adjacent the front portion of the LED. A second end of the light guide is positioned remotely from the LED. The first end of the light guide receives light from the LED and the second end of the light guide emits light that passes through the light guide. 
         [0013]    In configurations with a reflector, the LED may be disposed in front of or opposite the reflector and emits light into the reflector. The reflected light that is emitted from the lighting unit travels in a reverse direction from the light emitted from the LED. A lens in front of the LED emitting face may partially focus the LED light to direct more light into the reflector. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0014]      FIG. 1  is a perspective view of an LED lighting unit replacing a conventional bulb in a lighting appliance. 
           [0015]      FIG. 2  is a side elevation sectional view of a first embodiment of the present invention including a reflector. 
           [0016]      FIG. 3  is a side exploded perspective view of an LED light unit of the embodiment of  FIG. 1 . 
           [0017]      FIG. 4  is a side elevation sectional view of a second embodiment of the present invention including a light guide. 
           [0018]      FIG. 5  is a perspective view of an LED including a substrate and an emitter face. 
           [0019]      FIG. 6  is a side elevation sectional view of the light guide of the embodiment of  FIG. 4 . 
           [0020]      FIG. 7  is a side exploded perspective view of the embodiment of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]      FIG. 1  shows the replacement of a bulb in an appliance generally identified by the number  2 . An appliance  4 , with a socket  6  for mounting a bulb is shown. A conventional bulb  8  is removed and is being replaced with an LED lamp or unit  10  to reduce power consumption and heat generation by the appliance. LED unit  10  generally includes a light emitter to collimate light from the LED light source. Appliance  4  may be an arm lamp, a puck light, track lighting or a similar lighting device that may use a halogen, incandescent, fluorescent or other bulb with less efficient lighting characteristics than LED lighting unit  10 . 
         [0022]    A first embodiment of LED unit  10  is shown best in  FIGS. 2 and 3 . Referring first to  FIG. 2 , a side cross section view of unit  10  in a first embodiment shows a lighting unit housing  12  which supports a light emitter in the form of reflector  14 , and a plug base  16  which retains connector pins  18  and an insulator  20 . 
         [0023]    Housing  12  also supports LED assembly  22  comprising LED base  24  which holds LED  26  including LED lens  28 , sheath  30 , screw knob  32 , screw  34 , collar  36  and assembly member  38 . LED assembly  22  is connected to unit housing  12  and is supported opposite reflector  14  by one or more leg  40 . Leg  40  is secured at a first end to LED assembly member  38  and at a second end to unit housing  12 . LED assembly  22  is supported by leg  40  so the emitting face of LED  26  in LED base  24  emits light into reflector  14 . LED base  24  with LED  26  is also slidably mounted in sheath  30  which is secured to assembly member  38 . LED unit  10  has a longitudinal axis L 1  and the components of LED assembly  22  are assembled generally along the longitudinal axis L 1 . 
         [0024]    LED base  24  holds LED  26  in a first end. At a second and opposite end of LED base  24  is a bore. Collar  36  is retained in the bore at an outside circumference of collar  36 . Collar  36  retains a first end of screw  34  at an inside circumference. Screw  34  can rotate in collar  36  freely, but has limited motion along the screw length. LED base  24  slides in sheath  30  in operative relation to screw  34 . At a second end of screw  34 , knob  32  is sized to manually turn the screw. Between the first and second ends, screw  34  passes through a threaded hole in assembly member  38 . 
         [0025]    LED  26  and base  24  slide longitudinally in sheath  30  as screw  34  rotates in the threaded hole of assembly member  38 . Screw  34  moves in and out of member  38  longitudinally. LED  26  also moves in relation to the focal point of reflector  14 . The beam emitted by LED unit  10  widens or narrows in response to sliding movement of LED  26  and base  24  in sheath  30 . 
         [0026]    This is an example for illustration purposes only and should not be considered a limitation. LED assembly  22  may have a different configuration than that shown. LED assembly member  38  and sheath  30  could be a single unit. Screw  34  could be linked to LED base  24  without collar  36  and still be within the scope of this disclosure. The position of LED  26  may be adjusted by other means than screw  34 . 
         [0027]    Unit housing  12  may support power supply electronics  42 . LED  26  may require a different power than the power supplied by appliance  4  connected to unit  10 . Power supply  42 , where required, conditions the power supplied by appliance  4  to make it compatible with LED  26 . For example, power supply  42  may change the voltage from 120 volts to 12 volts. Power supply  42  may change alternating current to direct current. Electrical power is supplied to LED  26  through leg  40 . 
         [0028]    Reflector  14  has an outward facing concave surface when assembled into unit housing  12 . The concave surface has a highly polished or reflective face. The concave face may form a parabolic curve and is configured to collimate light from LED  26  and emit it as a narrow beam. 
         [0029]      FIG. 3  is an exploded view of LED unit  10  of  FIG. 2 . LED unit  10  again includes unit housing  12  which supports reflector  14 , and plug base  16  which retains connector pins  18  and insulator  20 , LED assembly  22  which includes LED base  24 , LED  26 , sheath  30 , knob  32 , screw  34 , threaded collar  36  and assembly member  38  and one or more legs  40 . 
         [0030]    Pins  18  and insulator  20  assemble in plug base  16  which is assembled to unit housing  12 . Power supply electronics  42  are assembled into unit housing  12 , and are operably connected to pins  18 , which supply power to electronics  42 . Reflector  14  is assembled to unit housing  12 , covering and enclosing power supply  42 . 
         [0031]    LED  26  with LED lens  28  and collar  36  are assembled to LED base  24 . Collar  36  in base  24  also retains a first end of screw  34 . Assembled LED base  24  slides into sheath  30 , which is assembled to assembly member  38 . Screw  34  is screwed into the threaded hole on the longitudinal axis L 1  of assembly member  38 . Knob  32  is fixed to, or formed in the second end of screw  34 . A first end of leg  40  is attached to LED assembly member  38  and a second end of leg  40  is attached to unit housing  12  to support LED assembly  22  above reflector  14 . Leg  40  may comprise more than one member. 
         [0032]    Plug base  16  may have terminals configured to connect to other socket form factors than those with pins. Plug base  16  may be configured with a first terminal with threads and a second terminal acting as a pressure contact. This plug base is similar to a screw in light bulb and may be sized to existing standards. 
         [0033]    In an alternate configuration of the first embodiment, LED assembly  22  may support a plurality of LEDs in LED base  24 . In another alternate configuration, LED  26  may not be movable in LED assembly  22  and may be fixed in place. 
       Embodiment of FIGS.  4 - 7   
       [0034]      FIG. 4  is a cross section side view of a second embodiment of an LED unit shown generally as  50 . In this embodiment, the light emitter is a substantially conical light guide made from a translucent plastic or other light permeable material. The phrase “substantially conical” is intended to cover a perfectly conical shape as well as one that is somewhat rounded as shown in  FIG. 4 . 
         [0035]    For clarity, similar numbering may be used in this and later figures as was used in previous figures. LED unit  50  again includes a unit housing  12 , a plug base  16  retaining plug pins  18  and insulator  20 , an LED  26  operably connected to plug pins  18 . LED unit  50  may further include a power supply  42  and a support frame  52  configured to align and support internal components, a light guide  54  and a front cover  56 . LED  26  may be mounted on and supported by power supply  42 . 
         [0036]    As depicted in  FIG. 4 , power supply electronics  42 , support frame  52 , LED  26  and elongated, substantially conical light guide  54  assemble into unit housing  12 . Front cover  56  may form an annular ring. Front cover  56  assembles to unit housing  12  and may include a stepped hole or a retaining lip  58  on the inside circumference to retain the light guide. The unit housing is normally internally threaded to receive front cover  56 . 
         [0037]      FIG. 5  is a side view of LED  26 . LED  26  typically comprises LED emitter  62  on a substrate  64  which extends laterally beyond LED emitter  62 . 
         [0038]      FIG. 6  is a side cross section view of light guide  54 . Light guide  54  may be manufactured from a single piece of material formed in the desired shape. Light guide  54  may be formed of a transparent, rigid material, with a high index of refraction such as glass, Plexiglas or other polymer. As depicted in the same figure, light guide  54  generally includes an admitter face  70 , a first emitter face  72 , a hole  74  in emitter face  72 , and a side wall  76  and a second emitter face  78  forming the bottom of hole  74 . Side wall  76  extends between first emitter face  72  and second emitter face  78 . 
         [0039]    Admitter face  70  typically includes three faces. The first face, which shall be referred to as an annular base  80 , is in the general configuration of an annular ring. In the depicted embodiment, annular base  80  contacts LED substrate  64  when annular base  80  is assembled into unit housing  12 . The second face shall be referred to as a protrusion  82  facing LED emitter  62 . The third face shall be referred to as an interior face  84 . Interior face  84  extends from annular base  80  to protrusion  82 . 
         [0040]    Protrusion  82  and emitter face  78  may be curved as shown to form hemispheres, but may have other shapes to form faces of different configurations. Side wall  86  may form a generally parabolic surface as shown in the preferred embodiment of  FIG. 6 . Side walls  86  may have straight sides to form a generally cylindrical or a generally conical shape (not shown). 
         [0041]    Light guide  54  may not include hole  74  in emitter face  72 . Emitter face  72  may be a smooth and continuous surface. 
         [0042]    A well known property of light guide  54  is that the light exiting the light guide at emitter faces  72  and  78 , where the light guide is sufficient in length, will be relatively uniform in brightness. This relatively uniform brightness is due to the mixing within light guide  54  due to multiple reflections within the light guide. 
         [0043]    Referring again to  FIG. 4 , light guide  54 , when assembled, is operatively coupled to LED  26 . Light guide  54  is designed to admit all of the light from LED  26 , and emit the light as a substantially collimated beam from emitter faces  72  and  78  with relatively uniform brightness. Light guide  54  may include a protruding key (not shown) on sidewall  86  which may align light guide  54  to unit housing  12  or front cover  56 . 
         [0044]      FIG. 7  is a side perspective exploded view of LED unit  50  of  FIG. 4 . LED unit  50  again includes unit housing  12 , plug base  16  which supports connector pins  18  and insulator  20 , LED  26 , power supply  42 , support frame  52 , light guide  54 , and front cover  56 . Pins  18  and insulator  20  assemble in plug base  16  and are assembled to unit housing  12 . Power supply electronics  42  and support frame  52  are assembled into unit housing  12  and are operably connected to pins  18  which supply power to electronics  42 . LED  26  is assembled to power supply electronics  42 . 
         [0045]    Admitter face  70  of light guide  54  is assembled over LED  26  so annular base  80  contacts substrate  64 . Front cover  56  is assembled to unit housing  12 . Primary emitter face  72  seats on retaining lip  58 . Light guide  54  is held between lip  58  and LED substrate  64 . In an alternate configuration (not shown), annular base  80  has an inside diameter larger than the LED substrate  64 . In this configuration, annular base  80  abuts a flat surface of power supply electronics  42 , and LED  26 , including substrate  64 , is seated into admitter face  70 . 
         [0046]    Again referring to  FIG. 6 , as an example only, emitter face  72  of light guide  54  is 25 mm in diameter. Admitter face  70  is 9 mm in diameter at the outside of annular base  80 , and 5.6 mm at the inside of the annular base. Protrusion  82  may be a hemisphere, with a base that is 4 mm in diameter. The distance from the plane through the rim of emitter face  72  to annular base  80  is 19.3 mm. The diameter of LED emitter face  62  is 5.5 mm. In this depicted embodiment, the top of LED emitter face  62  is 4.6 mm above LED substrate  64 , with the top of hemispheric protrusion  82  being 14.6 mm below annular base  80 . When assembled, this provides a 0.1 mm clearance between the hemispheric protrusion  82  and LED emitter  28 . Hole  74  may be 11.2 mm deep and 5 mm in diameter. Light guide wall  86  forms a generally parabolic curve. 
         [0047]    Light guide  54  may be configured to accommodate a plurality of LEDs  26 . Annular base  80  may be wide enough to encompass multiple LEDs in admitter face  70 . Alternately, light guide  54  may have multiple admitter faces  70  in one light guide  54  such that each of multiple LEDs  26  has an annular base  80  and a protrusion  82  to admit light to the light guide. 
         [0048]    Lighting unit structural components such as unit housing  12 , plug  16 , LED assembly  22  and front cover  56  may be made from a metal such as aluminum or steel or a plastic such as ABS. Component materials may be selected to be compatible with lighting unit operation in harsh environments such as very high or very low ambient temperatures. 
         [0049]    Although the invention has been described in detail for the purpose of illustration, it is to be understood that such detail is solely for that purpose, and variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention, except as it may be limited by the claims. 
         [0050]    Applicants regard the subject matter of their invention to include all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties disclosed herein. No single feature, function, element or property of the disclosed examples is essential to all examples. The following claims define certain combinations and subcombinations which are regarded as novel and non-obvious. Other combinations and subcombinations of features, functions, elements and/or properties may be claimed through amendment of the present claims or presentation of new claims in this or a related application. Such claims, whether they are different, broader, narrower or equal in scope to the original claims, are also regarded as included within the subject matter of applicants&#39; invention.