WO2013097132A1

WO2013097132A1 - Light emitting diode lamp

Info

Publication number: WO2013097132A1
Application number: PCT/CN2011/084882
Authority: WO
Inventors: Jian Wang; Hong Zhao; Junhui Fei
Original assignee: GE Lighting Solutions, LLC
Priority date: 2011-12-29
Filing date: 2011-12-29
Publication date: 2013-07-04

Abstract

A lamp (400) comprises a light translucent body, a connector, a rectifier, and a plurality of light emitting diodes. The light emitting diodes are serially connected. The lamp(400) operates at greater than about 120 volts and at less than about 50mA. The light translucent body has a diameter of less than about 75mm.

Description

LIGHT EMITTING DIODE LAMP

BACKGROUND

[0001] The following relates to the illumination arts, lighting arts, electrical power arts, and related arts.

[0002] Light emitting diodes (LED or LEDs) are solid state devices that convert electric energy to light, and generally comprise one or more active layers of semiconductor material sandwiched between opposed doped layers. The terms LED, chip and die are used interchangeably throughout this disclosure. When a bias is applied across the doped layers, holes and electrons are injected into the active layer where they recombine to generate light.

[0003] FIG. 1 shows a conventional LED package 10. In the LED package 10, one or more LED chips 12 are mounted onto a carrier such as a printed circuit board (PCB), substrate or submount 13. A reflector 14 can be included on the submount 13 that surrounds the LED chip(s) 12 and reflects light emitted by the LED chips 12 away from the package 10. Different reflectors can be used such as metal reflectors, omni-directional reflectors (ODRs), and distributed Bragg reflectors (DBRs). One or more wirebond connections 17 are made between ohmic contacts on the LED chips 12 and electrical traces 15A, 15B on the submount 13. The mounted LED chips 12 are then covered with an encapsulant 16, which may provide environmental and mechanical protection to the chips while also acting as a lens. The metal reflector 14 is typically attached to the carrier by means of a solder or epoxy bond. Higher light output can be achieved by mounting several LED packages onto a single circuit board.

[0004] FIG. 2 shows a sectional view of an integrated LED package array 20 comprising two LED packages 22 mounted to a substrate/submount 24 to achieve higher luminous flux. Typical arrays include many LED packages, with FIG. 2 only showing two for ease of understanding and illustration.

[0005] Light emitting diode LED-based lamps are employed in diverse lighting and illumination systems, such as traffic lighting, overhead (e.g., post-mounted) lamps, billboard and other commercial illuminated signage, and so forth. These lighting or illumination systems are sometimes in the context of commercial or industrial applications, such as commercial signage, parking lot illumination for retail centers, malls, supermarkets, and the like, or so forth. In addition, LED lighting and illumination systems have recently become more popular in general illumination applications such as household lamps and down lighting, These systems are considered replacement options for traditional incandescent lamps (A19, for example) and reflector lamps (PAR, for example).

[0006] FIG. 3 represents a typical LED-based lamp design. The device 30 includes a light emitting device 32 that generates light generally along a longitudinal axis 34. The light emitting device 32 is a light emitting diode (which can comprise a plurality of LEDS) that is mounted to a substrate 33. The substrate 33 may be a circuit board that includes conductive traces or contacts that are electrically coupled with the light emitting device 32.

[0007] The device 30 includes an outer assembly 38 that extends from a base end 35 to a light emitting end 36 along the longitudinal axis 34. The base end 35 is disposed opposite the light emitting end 36. In the illustrated embodiment, the outer assembly 38 has a funnel shape. For example, a diameter of the outer assembly 38 may be the greatest at the light emitting end 36 and gradually decrease to a smaller diameter at or near the base end 31 .

[0008] The light generated by the light emitting device 32 emanates from the light emitting end 36 away from the base end 37. The base end 37 may include a mounting element 31 . In the illustrated embodiment, the mounting element 31 is a GU10-compatible post. The device may be configured to mate with a non-GU10 compatible socket as an alternative. For example, the mounting device 31 may be electrically coupled with wires, wire leads, and/or screw or wedge connector that supply power to the light emitting device 32.

[0009] In the illustrated embodiment, the outer assembly 38 is a heat sink. The outer assembly 38 conducts or communicates thermal energy created by the light emitting device 32 to the exterior surface of the outer assembly 38. For example, the light emitting device 32 generates thermal energy during the generation of light. The thermal energy is conducted from the light emitting device 32 to the outer assembly 38. The outer assembly 38 communicates the thermal energy to the exterior surfaces of the outer assembly 38 such that at least some of the thermal energy is dissipated into the surrounding atmosphere.

[0010] In the illustrated embodiment, the outer assembly 38 includes, several ribs and channels 39 along the exterior surface of the outer assembly 38. The rib channels are elongated and extend along the exterior surface of the outer assembly 38 from the light emitting end 36 toward the base end 35. The ribs channel are oriented approximately parallel to one another along the exterior surface of the outer assembly 38.

[0011] An optical lens 40 is disposed at or proximate to the light emitting end 36 of the outer assembly 38. The optical lens 40 is a unitary, light transmissive body that transmits light generated from the light emitting device 32 out of the device 30. The optical lens 40 includes or is formed from a light transmissive material that may refract the light generated by the light emitting device 32.

BRIEF SUMMARY

[0012] According to one embodiment, a lamp comprising a light translucent body, a base connector, a rectifier, and a plurality of light emitting diodes is provided. The light emitting diodes are serially connected. The light emitting diodes receive electrical power from the rectifier at equal to or greater than about 120 volts and at less than 50mA. The light translucent body has a diameter of less than about 75mm. [0013] A lamp comprised of a housing having one of a GU-10 or R50 lamp outline and including at least 72 light emitting diode chips connected serially, the lamp further including a base having a rectifier converting AC voltage to DC voltage, and an electrical connector selected from one of an Edison screw base, a bayonet connector base, a double constant bayonet base, a bipin base and a GU turn and lock base.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention may take form in various components and arrangements of components, and in various process operations and arrangements of process operations. The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the invention.

[0015] FIGURE 1 is a sectional view of a prior art LED package.

[0016] FIGURE 2 is a sectional view of a prior art LED package.

[0017] FIGURE 3 is a perspective view of a prior art LED package.

[0018] FIGURE 4 is a perspective view of a lamp of the present disclosure.

[0019] FIGURE 5 is a top plan view of an LED array of Figure 4.

[0020] FIGURE 6 is a schematic representation of the electronic circuit of the present disclosure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0021] In commercial and industrial settings, available electrical power can be three-phase AC power, such as 120/208 V as is typical in the United States, or 220/380 V three phase power, as is typical in China, or so forth. The three-phase power is typically high voltage (for example, over 100 volts per phase). [0022] LED-based lamps, on the other hand, are typically driven by DC power, since the diodes have polarity and do not operate under "negative" bias. Light emitting diodes also typically operate at relatively low voltage (a few volts across the pin junction) and at relatively high current (such as a few hundred milliamperes to a few amperes current flow through each diode). Thus, LED-based lamps are generally not well-matched to three-phase AC power. Accordingly, a power conversion system is typically included with LED-based lamps.

[0023] Moreover, the conventional method of building an LED lamp is to use multiple high current low voltage LEDs, such as 350mA, 3.5V LEDs. To make an LED lamp compatible with AC power supplies, a driver converter is necessary. The driver converter is used to create the high drive current and low forward voltage. The size of the driver converter is usually significant to handle these requirements. In the case of LED replacement lamps for certain incandescent applications, for example, A19 or PAR60 and larger lamps, it is possible to provide a suitable driver converter, even if it is economically challenging. However, in the case of LED replacement lamps for small incandescent platforms, such as GU10 and R50 lamps and smaller, there is no practical way to provide an inboard driver converter that accomplishes conversion of the magnitude discussed above. Moreover, large driver electronics are not suitable for use in a small outline bulb such as GU10 and R50.

[0024] There is an alternative existing technology called the "AC LED" which is a multichip LED technology that enables the LED to be operated directly on line voltage without an electronics driver. However, the AC LED suffers from a voltage fluctuation issue wherein a 10% input voltage variation will cause 25% light output variation.

[0025] According to the present disclosure, an LED lamp having a standard electrical connection or standard base is suitable for replacing an incandescent lamp having a standard electrical connection or standard base. LED lamps which replace standard incandescent lamps of the GU-10 and R50 size and smaller are of particular interest. These lamps therefore have a diameter less than about 75mm and a maximum length less than about 100mm. In this regard, the lamps are not sufficiently large to house an economical driver converter capable of converting high voltage AC to low voltage high current DC.

[0026] Referring now to Figure 4, an LED-based lamp 400 that operates at a high voltage and low current rather than the existing low voltage and high current configurations is displayed. Lamp 400 is a standard PAR lamp design outline having reflector cup 402 including an internal reflective surface 404. The reflective surface can be achieved by any methodology known in the art including silver or aluminum coatings or multi-layer thin films.

[0027] An LED array 406 is disposed within reflector cup 402. As depicted, LED array 406 includes four individual arrays 406A, 406B, 406C and 406D.

[0028] With reference to Figure 5, each array includes 28 serially connected die (see Figure 6). A typical lamp in accordance with this disclosure will have at least 72, or at least 1 12 LED die. The number of die and arrays can be selected to provide a forward voltage of at least about 90 VDC. Exemplary arrays are available from Seoul Semi (A4) and LumiLeds (Luxeon H). More particularly, the die 408 are disposed on a printed circuit board and serially interconnected via conductive tracing 410 (only selective representative tracings are numbered). Each array 406A-D is similarly serially interconnected by wirebands 412.

[0029] Referring again to Figure 4, lamp 400 includes a base element 414 which house an AC to DC rectifier, designed to convert high voltage AC to high voltage DC. The high voltage and low current operation is functional because the multiple LEDs are connected in series.

[0030] The number of die can be tailored or customized to meet the available voltage level or the voltage level can be tailored to meet the number of junctions presented by the die. The LED chip operating voltage can be tailored for the end application by selecting the appropriate number and size of LEDs. [0031] For example, using U.S. grid power of approximately 150 volts (peak to valley), LEDs can be serially connected to achieve LEDs at about 3 volts per junction. In this example, three arrays of 28 LED chips each could be employed. For European grid power of over approximately 350 volts (peak to valley) the monolithic chip can comprise over 100 serially connected LEDs. A high voltage and low current lamp design allows for the use of more efficient and small sized driver converter.

[0032] The term "standard electrical connection" is understood herein to mean an electrical connection that is commonly used for illuminants and in particular for incandescent lamps, and a "standard base" is correlatively understood to mean a base that is commonly used for illuminants and in particular for incandescent lamps. For example, the standard base can be an Edison base, a bayonet base, a plug-in base or a base with connecting cables. An Edison base has an Edison thread, for example E14, E26 or E27, as its standard electrical connection and is commonly used, for example, in general lighting or for signal lights. A bayonet base comprises a bayonet lock. It is commonly used, for example, in motor vehicle lighting, for example having the type designation BAU15s, and in general lighting, e.g. under the type designations B15d and GU10, particularly for halogen incandescent lamps. A plug-in base, for instance a G9, GU5.3 or GY6 base, comprises in one configuration electrical connection pins as its standard electrical connection.

[0033] The preferred embodiments have been illustrated and described. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

We claim:

1. A lamp comprising a light translucent body, a base connector, a rectifier, and a plurality of light emitting diodes (LEDs), said light emitting diodes being serially connected and receiving electrical power from said rectifier at equal to or greater than about 120 volts and at less than 50mA, wherein said light translucent body has a diameter of less than about 75mm.

2. The lamp of claim 1 wherein said base connector is one of an Edison screw base, a bayonet connector base, a double constant bayonet connector base, a bipin base, and a GU turn and lock connector base.

3. The lamp of claim 1 having a maximum length of less than 100mm.

4. The lamp of claim 1 including at least 25 LEDs.

5. The lamp of claim 4 including at least 64 LEDs.

6. The lamp of claim 1 wherein said LEDs reside on at least two arrays, said arrays being interconnected serially.

7. The lamp of claim 1 , said lamp provides a forward voltage of at least about 90 VDC.

8. The lamp of claim 1 wherein said LEDs reside on a printed circuit board.

9. The lamp of claim 1 wherein said rectifier converts an alternating current power supply having a voltage greater than 120 volts to a direct current power supply having a voltage greater than about 120 volts.

10. The lamp of claim 1 wherein said LEDs receive electrical power at a voltage greater than 250 volts.

1 1 . The lamp of claim 1 having the outline of a GU-10 lamp.

12. The lamp of claim 1 having the outline of an R50 lamp.

13. The lamp of claim 1 which a driver converter is not associated with the lamp.

14. The lamp of claim 1 including at least 1 12 LED die.

15. A lamp comprised of a housing having one of a GU-10 or R50 lamp outline and including at least 72 light emitting diode chips connected serially, the lamp further including a base having a rectifier converting AC voltage to DC voltage, and an electrical connector selected from one of an Edison screw base, a bayonet connector base, a double constant bayonet base, a bipin base and a GU turn and lock base.