LED lamp

An LED lamp includes: a lamp shell; a passive heat dissipating element having a heat sink, and the heat sink including fins and a base and connecting to the lamp shell; a power source disposed in the lamp shell; and a light board connecting to the heat sink and including LED chips electrically connected to the power source. A chamber of the lamp shell is formed with a first heat dissipating channel. The first heat dissipating channel has a first air inlet at an end of the lamp shell. Another end of the lamp shell has a heat dissipating hole. A second heat dissipating channel is formed in the fins and base. The second heat dissipating channel has a second air inlet. Air flows into the second air inlet, passes through the second heat dissipating channel and flow out from spaces between every adjacent two of the fins.

CROSS-REFERENCE TO RELATED APPLICATIONS

FIELD OF THE INVENTION

The invention relates to lighting, particularly to high-power LED lamps.

BACKGROUND OF THE INVENTION

Because LED lamps possess advantages of energy saving, high efficiency, environmental protection and long life, they have been widely adopted in the lighting field. For LED lamps used as an energy-saving green light source, a problem of heat dissipation of high-power LED lamps becomes more and more important. Overheating will result in attenuation of lighting efficiency. If waste heat from working high-power LED lamps cannot be effectively dissipated, then the life of LED lamps will be directly negatively affected. As a result, in recent years, solution of the problem of heat dissipation of high-power LED lamps is an important issue for the industry.

In some applications, there may be a weight limit for a whole LED lamp. For example, when an LED lamp is provided with a lamp head with a specific specification and the LED lamp is used in a hanging manner, a maximum weight of the LED lamp is subject to a limited range. Accordingly, other than necessary components such as a power source, a lamp cover and a lamp shell, weight of a heat sink of an LED lamp is restricted to a limited range. For those high-power LED lamps (also known as LED high-bay lights), such as those using power of 150 W˜300 W, their luminous flux can reach about 20000 lumens˜45000 lumens. In this case, a heat sink must dissipate heat from an LED lamp with 20000˜45000 lumens under its weight limit.

Currently mainly available heat dissipating components for LED lamps are fans, heat pipes, heat sinks or their combination to dissipate heat of an LED lamp by thermal conduction, convection and/or radiation. Under a condition of merely adopting passive heat dissipation (without a fan), an overall effect of heat dissipation depends upon thermal conductivity and heat dissipation area of material of the heat sink. Under a condition of the same thermal conductivity, heat sinks merely rely on both convection and radiation to dissipate heat regardless of types thereof. Heat dissipating ability of these two types of heat sinks is in proportion to heat dissipating area thereof. Thus, under a precondition of a weight limit for a heat sink, how to improve efficiency of heat dissipation of a heat sink is an important way to enhance quality of LED lamps and reduce cost of LED lamps.

A currently available LED lamp generally includes a light source, a heat sink, a power source, a lamp shell and a lamp cover. The light source is fastened onto the heat sink. The power source is disposed in the lamp shell. The lamp shell connects to the heat sink. The lamp shell includes a head for connecting a lamp socket. Currently available LED lamps have the following drawbacks:

1. Concerns with designs of heat sinks:

Under a condition of merely adopting a manner of passive heat dissipation within the weight limit of a heat sink, a problem of heat dissipation of LEDs of some high-power LED lamps may exist so that heat from working LEDs cannot be dissipated timely. Life of these LEDs will be affected after long term use. As an example, a heat sink may include fins, but a relative positional relationship between the fins and LEDs may be arranged so as to make a heat conduction path of the heat from the LEDs to the fins too long to dissipate heat of LEDs fast enough.

Further, certain convection designs between fins of a heat sink may be impractical or ineffective. For example, Chinese patent No. 2047174890 teaches a fanless LED projection light. There is no convection from bottom to top between wing sheets of '489's heat sink so that heat in the air cannot be timely dissipated after heat in the wing sheets has been radiated to the air. As a result, the temperature of air around the wing sheets increases. An important factor of affecting thermal radiation of the wing sheets is a temperature difference between the wing sheets and air therearound. Accordingly, a raise in air temperature would affect thermal radiation of the wing sheets.

Moreover, certain structural designs of fins of a heat sink may be impractical or ineffective. For example, Chinese patent No. 107345628A teaches an LED lamp whose fins in a direction of a height of the LED lamp have the same width. For heat dissipation of an LED lamp, fins near LEDs in a direction of a height of the LED lamp are mainly used for conducting heat of the LEDs to the fins and the fins away from the LEDs are used for dissipating heat to air therearound by thermal convection and radiation. The fins away from the LEDs dissipate heat to air therearound by thermal convection and radiation, so no excessive heat dissipating area is required. However, the design of fins of the LED lamp disclosed by '628 would cause increase of overall weight of the LED lamp without proportioned increase of efficiency of heat dissipation.

In addition to the above issues, fins of a heat sink may still have some structural problems. For example, a high-power LED lamp with a larger size, whose width may be above 150 mm and height may be above 180 mm, should match fins with correspondingly larger length and width. If such fins lack sufficient support, they tend to be skewed in assembling. In addition, an unreasonable design of radial outlines of fins would reduce an effect of heat dissipation and may not properly match a lamp.

2. Concerns with arrangement of power sources:

For some high-power LED lamps, such as power of up to 150 W˜300 W, heat dissipation of their power sources is also important. If heat from a power source of a working LED lamp cannot be dissipated timely, then life of some electronic components will be affected and finally life of a whole lamp will be affected. Usually, there is no effective heat management between a heat sink and a power source in a currently existing LED lamp. This will result in mutual influence between heat of a heat sink and a power source. For example, Chinese patent No. 2031903640 teaches a heat dissipating structure with double-channeled air convection for a lamp. No effective thermal isolation is provided between its fins and a chamber (a part of the chamber is directly formed on the heat sink) receiving a power source or between its light source and the chamber receiving the power source. Heat from the fins and the light source may therefore directly enter the chamber through thermal conduction to affect the power source in the chamber.

Furthermore, certain layouts of electronic components of a power source may cause problems for heat dissipation. For example, laying out heat-generating components (such as resistors, inductors and transformers) together may be disadvantageous to forming of temperature gradients between the heat-generating components and air therearound so as to adversely affect efficiency of heat radiating from the heat-generating components to air. It is noted that when external air is thermally transferred to the power source and no particular design is provided, then bugs and dust tends to be attached on the power source to affect heat dissipation of the power source.

Besides the problem of heat dissipation, high-power LED lighting possesses relatively heavier weight and a higher working temperature, so a requirement of structure of high mechanic strength under a high temperature should be considered. A general high-power LED lighting is assembled by screwing components to connect. Considering a requirement of distance of insulated creepage, a lamp neck above a heat sink usually adopts a plastic material. The most common structure is that a casing of a plastic element is together with a lamp head thread, the lamp head is screwed to the casing and riveting pinholes are added to implement positioning connection. Connection using screws not only requires complicated process in manufacture, but also cost is higher. Thus, mechanic connection of high-power LED lighting is another important issue for these products.

When packing and shipping of LED lamps are involved, a lamp cover of an LED lamp protrudes from a light board. For example, in Chinese patent No. 107345628A, the lamp cover of the LED lamp may touch external objects to cause damage. Therefore, when packing and shipping, the lamp cover needs to be particularly protected to avoid damage resulting from collision. This will increase packing cost.

When considering light emission of LED lamps, usually, under an ideal condition, light from an LED lamp is expected to be projected onto a specific area under the LED lamp to guarantee intensity in this area. However, in fact, a considerably large part of light may be projected to a lateral area to cause waste of light and decrease of output efficiency of light. For example, Chinese patent No. 107345628A discloses a solid state lamp including a solid state light source on a circuit board. A part of the solid state light source is laterally disposed. A lamp is usually used with the light source. A solid state light source which is laterally disposed may use a lamp to reflect its light to project downward. In the process of reflection, there is typically light loss. Thus, efficiency of light emission will be adversely affected.

Furthermore, for circuits, a bias of conventional driving circuits is generated by acquiring voltage division on a mother line. In applications of HID-LED (High intensity Discharge-LED), however, large capacitors are usually used in conventional biasing circuits to avoid excessive power waste. This may cause a situation where the HID-LED cannot be lit up immediately. Typical starting time of general biasing is about 1 second. This can affect convenience of use.

OBJECT AND SUMMARY OF THE INVENTION

The LED lamp described in the present disclosure includes an LED (light emitting diode) lamp including a lamp shell, a passive heat dissipating element comprising a heat sink, the heat sink comprising fins and a base, and the heat sink connecting to the lamp shell; a power source disposed in the lamp shell; and a light board, connecting to the heat sink, and comprising LED chips electrically connected to the power source. A chamber of the lamp shell is formed with a first heat dissipating channel. The first heat dissipating channel has a first air inlet at an end of the lamp shell, another end of the lamp shell has a heat dissipating hole, a second heat dissipating channel is formed in the fins and base, the second heat dissipating channel has a second air inlet, and air flows into the second air inlet and passes through the second heat dissipating channel and finally flows out from spaces between every adjacent two of the fins.

The light board may be formed with an aperture communicating simultaneously with both the first heat dissipating channel and the second heat dissipating channel.

The aperture may be located in a central region of the light board, and the aperture may form an air intake of both the first heat dissipating channel and the second heat dissipating channel.

A weight of the heat sink may account for at least 50% of that of the LED lamp, and a volume of the heat sink may account for at least 20% of an overall volume of the LED lamp.

A volume of the heat sink may account for 20%˜60% of an overall volume of the LED lamp.

In certain embodiments, the heat sink comprises first fins and second fins, bottoms of both the first fins and the second fins in an axis of the LED lamp connected to the base, the first fins interlace with the second fins at regular intervals, and each of the second fins is of a Y-shape.

The LED lamp may further comprise a lamp cover with a light output surface and an end surface, wherein the end surface is formed with a vent, air flows into both the first heat dissipating channel and the second heat dissipating channel through the vent, the first air inlet is projected onto the end surface in an axis of the LED lamp to occupy an area on the end surface, which is defined as a first portion, another area on the end surface is defined as a second portion, and the vent in the first portion is greater than the vent in the second portion in area.

Various aspects of the disclosed embodiments may result in certain advantages, as described below.

1. Heat in the first heat dissipating channel from the working power source can be brought out. The second heat dissipating channel can enhance convection of the heat sink. Both the first and second heat dissipating channels can enhance efficiency of natural convection of the whole lamp so as to reduce required area of heat dissipation of the heat sink.

2. The aperture may simultaneously communicate with both the first heat dissipating channel and the second heat dissipating channel and the apertures may be located in a central region of the light board so that the aperture forms a common air intake of both the first heat dissipating channel and the second heat dissipating channel. As a result, area of the light board may be occupied as little as possible to prevent the region of the light board where LED chips are placed from being occupied by other air intakes.

3. Weight of the heat sink may account for above 50% of overall weight of the LED lamp, and volume of the heat sink may account for above 20% of overall volume of the LED lamp. Under a condition of the same thermal conductivity of the heat sink, the larger the heat sink accounting for a percentage of overall volume of the LED lamp is, the larger the available area of heat dissipation is. As a result, to a certain extent, when volume of the heat sink accounts for above 20% of overall volume of the LED lamp, there is more usable space in the heat sink to increase area of heat dissipation.

4. By using Y-shaped second fins, the heat sink can obtain more area of heat dissipation under the same volume.

5. The vent in the first portion may have greater area than the vent in the second portion, which may be advantageous to most air entering the first heat dissipating channel so as to improve heat dissipation to the power source and to prevent electronic components of the power source from aging rapidly due to being heated.

DETAILED DESCRIPTION OF THE EMBODIMENTS

To make the present invention understandable and readable, the following disclosure will now be described in the following embodiments with reference to the drawings. The following descriptions of various embodiments of this invention are presented herein for purpose of illustration and giving examples only. It is not intended to be exhaustive or to be limited to the precise form disclosed. These example embodiments are just examples and many implementations and variations are possible without the details provided herein. Some terms mentioned in the following description, such as “in an axis”, “above” or “under”, are used for clear structural relationship of elements, but not a limit to the present invention. In the present invention, the terms “perpendicular”, “horizontal” and “parallel” are defined in a range of ±10% based on a standard definition. For example, “perpendicular” (perpendicularity) means the relationship between two lines which meet at a right angle (90 degrees). However, in the present invention, “perpendicular” may encompass a range from 80 degrees to 100 degrees. In addition, “using condition” or “using status” mentioned in the present disclosure means a “head-up” hanging scenario. Exceptions will be particularly described.

FIG. 1is a structural schematic view of an embodiment of an LED lamp according to certain aspects of the invention.FIG. 2is a schematic cross-sectional view of the LED lamp ofFIG. 1.FIG. 3is an exploded view of the LED lamp ofFIG. 1. As shown in the figures, the LED lamp includes a heat sink1, a lamp shell2, a light board3, a lamp cover4and a power source5. In this embodiment, the light board3is connected to the heat sink1by attachment for rapidly transferring heat from the light board3to the heat sink1when the LED lamp is working. In some embodiments, the light board3is riveted to the heat sink1. In some embodiments, the light board3is screwed to the heat sink1. In some embodiments, the light board3is welded to the heat sink1. In some embodiments, the light board3is adhered to the heat sink1. In this embodiment, the lamp shell2is connected to the heat sink1, the lamp cover4covers the light board3to make light emitted from the light board3pass through the lamp cover to project out. The power source5is located in a chamber of the lamp shell2and the power source5is EC to the LED chips311for providing electricity.

FIG. 4is a schematic cross-sectional view of the LED lamp. As shown inFIGS. 2 and 4, the chamber of the lamp shell2of this embodiment is formed with a first heat dissipating channel7a. An end of the first heat dissipating channel is formed with a first air inlet2201. An opposite end of the lamp shell2is formed with a venting hole222(at an upper portion of the lamp neck22). Air flows into the first heat dissipating channel2201and flows out from the venting hole222for bringing out heat in the first heat dissipating channel7a(primarily, heat of the working power source5). As for the path of heat dissipation, heat generated from the heat-generating components of the working power source5is transferred to air (around the heat-generating components) in the first heat dissipating channel7aby thermal radiation first, and then external air enters the first heat dissipating channel7aby convection to bring out internal air to make heat dissipation. In this embodiment, the venting hole222at the lamp neck22can also make direct heat dissipation.

As shown inFIGS. 1, 2 and 4, a second heat dissipating channel7bis formed in the fins and the base13of the heat sink1. The second heat dissipating channel7bhas a second air inlet1301. In this embodiment, the first air inlet2201and the second air inlet1301share the same opening formed on the light board3. This will be described in more detail later. Air flows from outside of the LED lamp into the second air inlet1301, passes through the second heat dissipating channel7band finally flows out from spaces between the fins11so as to bring out heat of the fins11to enhance heat dissipation of the fins11. As for the path of heat dissipation, heat generated from the LED chips is conducted to the heat sink1, the fins11of the heat sink1radiate the heat to surrounding air, and convection is performed in the second heat dissipating channel7bto bring out heated air in the heat sink1to make heat dissipation.

As shown inFIGS. 1 and 4, the heat sink1is provided with a third heat dissipating channel7cformed between adjacent two of the fins11or in a space between two sheets extending from a single fin11. A radial outer portion between two fins11forms an intake of the third heat dissipating channel7c. Air flows into the third heat dissipating channel7cthrough the radial outer portion of the LED lamp to bring out heat radiated from the heat sink11to air.

FIG. 5is a perspective view of the LED lamp of an embodiment, which shows assembling of the heat sink1and the lamp cover4.FIG. 6is a structural schematic view ofFIG. 5without the light output surface43. As shown inFIGS. 5 and 6, in this embodiment, the lamp cover4includes a light output surface43and an end surface44with a vent41. Air flows into both the first heat dissipating channel7aand the second heat dissipating channel7bthrough the vent41. When the LED chips311(shown inFIG. 6) are illuminated, the light passes through the light output surface43to be projected from the lamp cover4. In this embodiment, the light output surface43may use currently available light-permeable material such as glass, PC, etc. The term “LED chip” mentioned in all embodiments of the invention means all light sources with one or more LEDs (light emitting diodes) as a main part, and includes but is not limited to an LED bead, an LED strip or an LED filament. Thus, the LED chip mentioned herein may be equivalent to an LED bead, an LED strip or an LED filament. As shown inFIG. 5, in this embodiment, the ratio of area of the light output surface43to area of the end surface44is 4˜7. Preferably, the ratio of area of the light output surface43(area of a single side of the light output surface43, i.e. area of surface of the side away from the LED chips311) to area of the end surface44(area of a single side of the end surface44, i.e. area of surface of the side away from the LED chips311, including area of the vent41) is 5˜6. More preferably, the ratio of area of the light output surface43to area of the end surface44is 5.5. The end surface44is used for allowing air to pass to enter both the first heat dissipating channel7aand the second heat dissipating channel7b. The light output surface43allows light from the light source to output. As a result, a balance can be accomplished between the light output and the heat dissipation. In this embodiment, to satisfy the requirement of air intake of both the first heat dissipating channel7aand the second heat dissipating channel7b, the ratio of area of the lamp cover4to area of the end surface44is 6˜7. As a result, a balance can be accomplished between the light output and air required by the heat dissipation.

In this embodiment, area of the light output surface43(area of a single side of the light output surface43, i.e. area of surface of the side away from the LED chips311) is above three times as large as area of light emitting surface of all the LED chips31but does not exceed ten times. Width of the light output region can be controlled when it is provided sufficiently.

As shown inFIGS. 5 and 6, in this embodiment, an inner reflecting surface4301is disposed inside the light output surface43of the lamp cover4. The inner reflecting surface4301is disposed in the inner circle of the array of LED chips311. In an embodiment, an outer reflecting surface4302is disposed in the outer circle of the array of LED chips311. The outer reflecting surface4302corresponds to the LED chips311on the light board3. The arrangement of both the inner reflecting surface4301and the outer reflecting surface4302is used for adjusting a light emitting range of the LED chip set31to make the light concentrated and to increase brightness in a local area. For example, under the condition of the same luminous flux, illuminance of the LED lamp can be increased. In one example, all the LED chips311in this embodiment are mounted on the bottom side of the light board3(in a using status). In this embodiment, the LED lamp of the present embodiment do not emit lateral light from the LED chips311. When working, the primary light emitting surfaces of the LED chips311are completely downward. At least 60% of the light from the LED chips311are emitted through the light output surface43without reflection. As a result, in comparison with those LED lamps with lateral light (the lateral light is reflected by a cover or a lampshade to be emitted downward, and in theory there must be part of light loss in the process of reflection.) The LED chips311in this embodiment possess better light emitting efficiency. In one example, under the condition of the same lumen value (luminous flux), the LED lamp in the present embodiment possesses higher illuminance. And the emitted light can be concentrated to increase illuminance in a local area by the arrangement of both the inner reflecting surface4301and the outer reflecting surface4302, for example, in an area under the LED lamp between 120 degrees and 130 degrees (a light emitting range under the LED lamp between 120 degrees and 130 degrees). When the LED lamp is installed at a relatively high position, in the same angular range of light emitting, the lit area of the LED lamp still satisfies the requirement and illuminance in this area can be higher.FIG. 7is a schematic view of light transmission of this embodiment andFIG. 8is a light pattern ofFIG. 7. As shown inFIGS. 5-8, in the aspect of the light emitting effect, in the projected area of the LED lamp, i.e. the projected area M under the LED lamp, there is a light concentrating area m within the projected area M, the LED lamp including the reflecting surface reflects at least part of light from the LED chips311onto the light concentrated area m to increase brightness of the light concentrated area m. The reflecting surface includes the inner reflecting surface4301and the outer reflecting surface4302. Both the inner reflecting surface4301and the outer reflecting surface4302reflect at least part of light from the LED chips311onto the light concentrated area m. Preferably, in this embodiment, at least 5% of luminous flux of the light source is reflected to pass through the light output surface43. In practice, total luminous flux of the light reflected by both the inner reflecting surface4301and the outer reflecting surface4302and emitted through the light output surface43is at least 1000 lm. Preferably, total luminous flux of the light reflected by both the inner reflecting surface4301and the outer reflecting surface4302and emitted through the light output surface43is at least 1500 lm. Total luminous flux of the light reflected by the outer reflecting surface4302is greater than that of the light reflected by the inner reflecting surface4301. This shows that, about the problem of glare resulting from an LED lamp with high lumen, disposing the outer reflecting area4302can reflect considerable part of lateral luminous flux. This can significantly reduce the glare. In this embodiment, the light concentrated area m is an annular region. In this embodiment, a center angle between an inner edge of the light concentrated area m and an axis of the LED lamp is 20 degrees, and a center angle between an outer edge of the light concentrated area m and an axis of the LED lamp is 50 degrees. In this embodiment, luminous flux of the light projected by the LED lamp onto the light concentrated area m accounts for 35%˜50% of the total luminous flux, so that the light concentrated area m possesses a better lighting effect. In addition, by the arrangement of both the inner reflecting surface4301and the outer reflecting surface4302, not only can the lateral light be reduced to prevent glare, but also at least part of light from the LED chips311can be reflected onto the projected area M to enhance illuminance in the projected area M.

The inner reflecting surface4301is used for reflecting part of light emitted from the innermost LED chips311of the LED chip set31. The outer reflecting surface4302is used for reflecting part of light emitted from the outermost LED chips of the LED chipset31. The outermost LED chips311are greater than the innermost LED chips311in number. The outer reflecting surface4302is greater than the inner reflecting surface4301in area. Because the outermost portion of the LED chip set31includes more LED chips than the innermost portion, larger reflecting area is beneficial to regulate light output.

In this embodiment, the inner reflecting surface4301and the outer reflecting surface4302have first area A1and second area A2, respectively. The LED chips311in the outermost portion of the LED chip set31and in the innermost portion of the LED chip set31are N1and N2in number, respectively. Their relationship is:
(A1/N1):(A2/N2)=0.4˜1

When the ratio of area of the inner reflecting surface4301corresponding to a single LED chip311in the innermost portion of the LED chip set31to area of the outer reflecting surface4302corresponding to a single LED chip311in the outermost portion of the LED chip set31falls in the above range, both the LED chips311in the innermost portion of the LED chip set31and the LED chips311in the outermost portion of the LED chip set31have a better effect of light output.

As shown inFIG. 6, an inner edge of the inner reflecting surface4301abuts against the light board3to prevent light from passing through gaps between the inner reflecting surface4301and the light board3to avoid loss of part of light. Identically, an inner edge of the outer reflecting surface4302abuts against the light board3to prevent light from passing through gaps between the outer reflecting surface4302and the light board3to avoid loss of part of light.

As shown inFIG. 2, in this embodiment, an angle a is formed between two extending lines of both the inner and outer reflecting surfaces4301,4302. The angle a is between 80 degrees and 150 degrees. Preferably, the angle a is between 90 degrees and 135 degrees. More preferably, the angle a is between 100 degrees and 120 degrees. A reflecting-cup-like structure is formed between the inner and outer reflecting surfaces4301,4302so as to control a light output range of the LED chips311or increase local intensity. In this embodiment, an angle between the outer reflecting surface4302and the light board2is 30 to 60 degrees. In some embodiments, the angle is 40 to 50 degrees.

As shown inFIG. 2, in this embodiment, the inner reflecting surface4301is lower than the outer reflecting surface4302in height. The height means a height of each of the both in an axis of the LED lamp. By the configuration of the inner reflecting surface4301being lower than the outer reflecting surface4302in height, decrease of a light distribution under the LED lamp can be avoided and a central portion of the light distribution region of the LED lamp can be prevented to be a dark part. In this embodiment, height of the outer reflecting surface4302in the axis of the LED lamp is not greater than 20 mm. Preferably, height of the outer reflecting surface4302in the axis of the LED lamp is not greater than 15 mm. On the other hand, to control overall height of the LED lamp, height of the outer reflecting surface4302accounts for not over 9% of overall height of the LED lamp. Preferably, height of the outer reflecting surface4302accounts for not over 6% of overall height of the LED lamp. As for functions of the outer reflecting surface4302, in some embodiments, height of the outer reflecting surface4302has to account for above 2% of overall height of the LED lamp. Preferably, in some embodiments height of the outer reflecting surface4302accounts for above 3% of overall height of the LED lamp. In one example, comprehensively considering control of height of the LED lamp and functions of reflection, light concentration, anti-glare, etc., it is necessary that height of the outer reflecting surface4302accounts for 2%˜9% of overall height of the LED lamp. Preferably, height of the outer reflecting surface4302accounts for 3%˜6% of overall height of the LED lamp.

In the LED lamps in some embodiments, both the inner and outer reflecting surfaces can be omitted, for example, a shading ring47may be disposed. As shown inFIG. 9, the shading ring47is disposed on a periphery of the lamp cover4to improve efficiency of light output of the lamp. A surface of the shading ring47possesses a reflecting effect (similar to the outer reflecting surface4302as mentioned in the previous embodiment). When the lamp cover4is attached on the heat sink1, the shading ring47nears a periphery of the light board3, for example, an outer diameter of the shading ring47is the same as or slightly greater than that of the light board3.

As show inFIGS. 5 and 6, in this embodiment, in order to prevent dust from covering on the LED chips311to reduce light efficiency of the LED chips or affect heat dissipation of the LED chips311, the LED chips311may be received in a sealed room. For example, a sealed chamber9is formed between the light output surface43, the inner reflecting surface4301, the outer reflecting surface4302and the light board3(this term “sealed” mentioned here may mean “without obvious pores”, not including unavoidable gaps in an assembling process). In some embodiments, when omitting both the inner and outer reflecting surfaces4301,4302, the sealed chamber9is formed between the light output surface43and the light board3or between the light output surface43, the heat sink1and the light board3.

FIG. 10is a perspective view of another embodiment of the LED lamp of the invention. It differs from the above embodiment by holes formed in the chamber9.FIG. 11is a schematic view ofFIG. 10without the light output surface43. As shown inFIGS. 10 and 11, in some embodiments, a chamber9is formed between the light cover4and the light board3. In detail, the chamber9is formed between the light output surface43, the inner reflecting surface4301, the outer reflecting surface4302and the light board3and the LED chips of the light board3are located in the chamber9. The chamber9has first apertures91and second apertures92. The first apertures91are configured to communicate with the outside, and the second apertures92are configured to communicate simultaneously with both the first heat dissipating channel7aand the second heat dissipating channel7b. In an aspect of heat dissipation, air convection is formed in the chamber9to bring out part of heat generated from the LED chips311, and outside air flows into the LED lamp through the chamber9so as to enhance convection in both the first heat dissipating channel7aand the second heat dissipating channel7b. In some embodiments, both the inner and outer reflecting surfaces4301,4302may be omitted. In one example, a chamber9is formed between the light output surface43and the light board3.

As shown inFIG. 10, in some embodiments, the light output surface43is provided with a hole to form the first apertures91. Preferably, the first apertures91are annularly located at a circumferential portion of the light output surface43to make it not affect the effect of light penetration of the light output surface43. In an aspect of structure, the light output surface43may be thermally deformed while the LED lamp is working. The first apertures91makes the light output surface43have a deformable space to prevent the light output surface43from being deformed to press the heat sink and cause damage of the light output surface43. In this embodiment, the first apertures91are annularly located at a circumferential portion of the light output surface43. As a result, air convection can be enhanced and structural strength of the light output surface43heated can also be reinforced.

As shown inFIG. 11, in some embodiments, the inner reflecting surface4301is provided with notches to form the second apertures92. In this embodiment, the second apertures92are annularly located at a circumferential portion of the inner reflecting surface4301. The ratio of the number of the second apertures92to that of the first apertures91is about 1:1˜2, preferably, 1:1.5. Thus, air intake and outtake can be balanced. In other embodiments, both the first apertures91and the second apertures92may also be formed at other portions of the lamp cover4such as the light board3or the base13of the heat sink1.

As shown inFIGS. 10 and 11, in some embodiments, a chamber9is formed between the light cover4and the light board3. In detail, the chamber9is formed between the light output surface43, the inner reflecting surface4301, the outer reflecting surface4302and the light board3and the LED chips311of the light board3are located in the chamber9. The chamber9has pressure release apertures to prevent temperature and pressure in the chamber from being raised by the working LED chips311. The pressure release aperture may be the first apertures91of the light output surface43, the second apertures92of the inner reflecting surface4301, or holes at the heat sink1or the light board3, which communicate with the chamber9.

As shown inFIG. 4, the distance between the light output surface43and the light board3is gradually outwardly larger and larger so as to make the light output surface43concave. Thus, in comparison with a flat surface, such a light output surface43can be structurally reinforced. In addition, the gradually smooth slant of the light output surface43does not has an angle so as to make thickness of the light output surface43even not to affect an effect of light output. Finally, in an aspect of use, the light board3generates heat from the light source while the LED lamp is working. If the light output surface43is a flat plane parallel to the horizon (the LED lamp is hung on a ceiling), then the heated light output surface43will horizontally thermally expand. As a result, the heat sink1may be damaged by being pressed. In this embodiment, when the light output surface43is of a concave shape, its expansion direction will be different from the above, for example, the expansion direction is divided into a horizontal portion and a downward vertical portion. This can reduce the thermal expansion in the horizontal direction to prevent the lamp cover4from being damaged by being pressed by the heat sink1.

As shown inFIG. 12, in some embodiments, the light output surface43may also be a flat plane, but a thermal expansion coefficient of the material of the light output surface43, a distance between the light output surface43and the heat sink1and resistance to deformation of the light output surface43should be seriously considered. For example, when the light output surface43is a flat plane, the distance between the light output surface43and the heat sink1should be large enough to guarantee expansion of the light output surface43not to be pressed by the heat sink1.

In some embodiments, the light output surface43is provided with an optical coating, for example, the light output surface43is coated with a diffusion film431through which light emitted from the LED chips311passes to penetrate the lamp cover4. In a few words, the diffusion film431diffuses light emitted from the LED chips311. The diffusion film431can be disposed in various manners, for example, the diffusion film may be coated or cover an inner surface of the light output surface43(as shown inFIG. 13a), or a diffusion coating coated on the LED chips311(as shown inFIG. 13b), or a cloak covering the LED chips311(as shown inFIG. 13c).

FIG. 14is a schematic view of the combination of the light board3and the lamp cover4. As shown, in some embodiments, a side of the light output surface43, which nears the LED chips311, i.e. an inner side of the light output surface43, is provided with an anti-reflection coating432to reduce reflection of light from the LED chips311to the light output surface43and increase light-permeability of the light output surface43. The refractive index of the anti-reflection coating432in this embodiment is between the reflectivity of air and glass. The anti-reflection coating432includes metal oxide which accounts 1%˜99% of overall weight of the anti-reflection coating432. The reflectivity of the anti-reflection coating432is less than 2%. Metal oxide in this embodiment may be zirconia, tin oxide, tin oxide, aluminum oxide, etc.

The diffusion film431(inFIG. 13) and the anti-reflection coating432may be used together or alternatively used. It can be selected according to actual requirements.

FIG. 15is a schematic view of an end surface44of the lamp cover4of an embodiment. As shown, the ratio of a total of cross-sectional area of the vent41to overall area of the end surface44(area of a single side of the end surface44, such as the side away from the LED chips311) is 0.01˜0.7. Preferably, the ratio of a total of cross-sectional area of the vent41to overall area of the end surface44is 0.3˜0.6. More preferably, the ratio of a total of cross-sectional area of the vent41to overall area of the end surface44is 0.4˜0.55. By limiting the ratio of a total of cross-sectional of the vent41to overall area of the end surface44to the above ranges, not only can air intake of the vent41be guaranteed, but also adjustment of area of the vent41is implemented under ensuring structural strength of the end surface44. When the ratio of area of the vent41to area of the end surface44is 0.4˜0.55, not only can air intake of the vent41be guaranteed to satisfy requirements of heat dissipation of the LED lamp, but also the vent41does not affect structural strength of the end surface44to prevent the end surface44with the vent41from being fragile due to collision or pressure.

FIG. 16is a schematic view of an end surface44of the lamp cover4of another embodiment. As shown inFIGS. 16 and 17, a periphery of the vent41has an enlarged thickness to form rib portions411. An air guide opening412in a direction of air intake of the vent41is formed between adjacent two of the rib portions411. A periphery of the vent41with an enlarged thickness can enhance structural strength of the end surface44to avoid reduction of overall structural strength due to the vent41. On the other hand, the air guide opening412has an effect of air guiding to make air flowing into the air guide opening412have a specific direction. In addition, when the end surface44is being formed, the rib portions411avoids reduction of overall structural strength of the end surface44. Thus, the end surface44is hard to be deformed because of the vent41to increase the yield rate of manufacture. In this embodiment, the rib portions411are formed on the side of the end surface44, which is adjacent to the light board.

As shown inFIG. 17, the thickness of periphery of the vent41is greater than that of other portions of the end surface44so as to improve strength of the parts around the vent41and the effect of air guiding.

As shown inFIG. 15, a diameter of a maximum inscribed circle of the vent41is less than 2 mm, preferably, 1.0˜1.9. mm. As a result, both bugs and most dust can be resisted, and venting efficiency of the vent41can be kept great enough. In one example, alternatively, the vent41defines both a length direction and a width direction, i.e. the vent has a length and a width, and the length is greater than the width. The largest width of inscribed circle of the vent41may be less than 2 mm. In an embodiment, the largest width is from 1 mm to 1.9 mm. In addition, the largest width of the vent41may be greater than 1 mm. If the width of the vent41is less than 1 mm, then more pressure is required to push air to enter the vent41, which is advanced for venting.

FIGS. 18a˜18gshow shapes of some embodiments of the vent41. As shown inFIGS. 18a-18g, the vent41may be circular, strip-shaped, arced, trapezoidal, diamond or their combination. As shown inFIG. 18a, when the vent41is configured to be circular, its diameter should be less than 2 mm to resist bugs and most dust and venting efficiency of the vent41can be kept great enough. As shown inFIGS. 18band 18c, when the vent41is configured to be strip-shaped or arced, its width should be less than 2 mm to accomplish the above effects. As shown inFIG. 18d, when the vent41is configured to be trapezoidal, its lower base should be less than 2 mm to accomplish the above effects. As shown inFIG. 18e, when the vent41is configured to be round-cornered rectangular, its width should be less than 2 mm to accomplish the above effects. As shown inFIGS. 18fand 18g, when the vent41is configured to be triangular or drop-shaped, a diameter of its maximum inscribed circle should be less than 2 mm.

In some embodiments, the vent41on the end surface44is multiple in number. For example, the vents41may be annularly arranged on the end surface44for even air intake. The vents41may also be radially arranged on the end surface44. The vents41may also be irregularly arranged.

In some embodiments, in an axial direction of the LED lamp, the vents may be inclined to an axis of the LED lamp. In one example, an angle is formed between an axis of the vent41and the axis of the LED lamp. As shown inFIG. 18h, axes of at least part of the vents41are inclined to the axis of the LED lamp, and the inclined directions of the part of vents41are toward the first air inlet2201of the first heat dissipating channel7a. Thus, after air passes the part of vents41, it will flow to the first air inlet2201of the first heat dissipating channel7ato perform convection for allowing more air to flow into the first heat dissipating channel7ato dissipate heat from the power source6therein. As shown inFIG. 18i, axes of at least part of the vents41are inclined to the axis of the LED lamp, and the inclined directions of the part of vents41are toward the second air inlet1301of the second heat dissipating channel7b. Thus, after air passes the part of vents41, it will flow to the second air inlet1301of the second heat dissipating channel7bto perform convection for allowing more air to flow into the second heat dissipating channel7bto dissipate heat from the heat sink1therein.

InFIG. 18a, there are two broken lines on the end surface44. The inner broken line represents a position the first air inlet2201(as shown inFIG. 2) is projected onto the end surface44. The region within the inner broken line is defined as a first portion (first opening region433). The region between the inner circle and the outer circle is defined as a second portion (second opening region434). In this embodiment, the first air inlet2201is projected onto the end surface in an axis of the LED lamp to occupy an area on the end surface44, it is the first portion (first opening region433). The other area on the end surface44is the second portion (second opening region434). The vent41in the first portion is greater than the vent41in the second portion in area. Such an arrangement is advantageous to making most air flow into the first heat dissipating channel7afor better effect of heat dissipation to the power source5and reduction of rapidly aging of electronic components of the power source5. These features are also available to the vent41in other embodiments.

In other embodiments, the first air inlet2201is projected onto the end surface44in an axis of the LED lamp to occupy an area on the end surface44, which may be a first portion (first opening region433). The other area on the end surface44may be a second portion (second opening region434). The vent41in the first portion is smaller than the vent41in the second portion in area. As a result, heat of the fins11can be better dissipated to perform better heat dissipation to the LED chips311and prevent a region around the LED chips311from forming high temperature. In detail, area of both the first portion and the second portion can be selected according to actual requirements.

In some applications, there may be a limit of overall weight of an LED lamp. For example, when an LED lamp adopts an E39 head, its maximum weight limit is 1.7 Kg. Thus, besides the fundamental elements such as a power source, a lamp cover and a lamp shell, in some embodiments, weight of a heat sink is limited within 1.2 Kg. For some high-power LED lamps, the power is about 150 W˜300 W, and their luminous flux can reach 20000 lumens to 45000 lumens. Under a limit of weight, a heat sink should dissipate heat from an LED lamp with 20000˜45000 lumens. Under a condition of heat dissipation of natural convection, usually power of 1 W needs area of heat dissipation of at least 35 square cm. The following embodiments intend to reduce area of heat dissipation for power of 1 W under guarantee of a receiving space of the power source5and effect of heat dissipation. Under a precondition of weight limit of the heat sink1and limit of the power source5, the best effect of heat dissipation can be accomplished.

As shown inFIGS. 1 and 2, in this embodiment, the LED lamp includes passive heat dissipating elements which adopt natural convection and radiation as a heat dissipating manner without any active heat dissipating elements such as a fan. The passive heat dissipating element in this embodiment includes a heat sink1composed of fins11and a base13. The fins11radially extend from and connect to the base13. When using the LED lamp, at least part of heat from the LED chips311is conducted to the heat sink1by thermal conduction. At least part of heat occurring from the heat sink1is transferred to external air by thermal convection and radiation. A diameter of a radial outline of the heat sink1, in a hanging status as shown in the figures, tapers off upward or is substantially in a taper shape for a better match with a lampshade. When the heat sink1in this embodiment is dissipating heat, at least part of heat is thermally radiated to air therearound to perform heat dissipation. An important factor of thermal radiation is emissivity. To improve emissivity of the heat sink1, surfaces of the heat sink in this embodiment are specially treated. For example, surfaces of the heat sink1are provided with radiation heat-dissipating paint or electrophoretic coating to increase efficiency of thermal radiation and to rapidly dissipate heat of the heat sink1. Another solution is forming a nanostructured porous alumina layer on the surfaces of the fins11by anodization in an electrolyte to form a layer of nanostructured porous alumina. As a result, ability of heat dissipation of the fins11can be enhanced without adding the number of the fins11. Alternatively, the surfaces of the fins11may be coated with an anti-thermal-radiation layer to reduce thermal radiation between the fins11. This can make more heat radiate to air. The anti-thermal-radiation layer may adopt paint or oxide coating, in which the paint may be normal paint or radiation heat dissipation paint. To further enhance heat dissipating effect of the heat sink1. Preferably, it further contains aluminum such as a small or micro amount of aluminum. Adopting both zinc and magnesium with the above percentages can form MgZn2with a reinforcement effect. This makes a heat treatment effect of the heat sink1far better than a one zinc binary alloy. Tensile strength can be significantly increased. Both resistance to stress corrosion and flaking corrosion resistance also increases. Performance of thermal conduction also increases. In sum, performance of heat dissipation of the heat sink1is better. In addition, the heat sink1may be made of a material with low thermal resistance/high thermal conductivity, such as an aluminum alloy. In some embodiments, the heat sink1can be made of an anodized 6061 T6 aluminum alloy with thermal conductivity k=167 W/m·k. and thermal emissivity e=0.7. In other embodiments, other materials are available, such as a 6063 T6 or 1050 aluminum alloy with thermal conductivity k=225 W/m·k. and thermal emissivity e=0.9. In other embodiments, other alloys are still available, such as AL 1100, etc. In some embodiments, a die casting alloy with thermal conductivity is available. In other embodiments, the heat sink1may include other metals such as copper.FIG. 19ais a cross-sectional view of the heat sink1of an embodiment. As shown, in some embodiments, the heat sink1is added with a heat dissipating pillar12. In detail, the heat sink1includes a heat dissipating pillar12, fins11and a base13. The heat dissipating pillar12connects to the base13. The fins11are radially disposed around the heat dissipating pillar12. A root portion of the fins11connects to the base13on a circle around the heat dissipating pillar12. The heat dissipating pillar12supports the fins11to prevent the fins11from being skewed in machining. When using the LED lamp, the heat dissipating pillar12or the base13transfers heat from the LED chips311to the fins11. The heat dissipating pillar12is a hollow body with two opening ends, for example, the heat dissipating pillar12may be a hollow cylinder. The heat dissipating pillar12may be made of a material which is the same as the heat sink1. This material possesses great thermal conductivity, such as an alloy, to implement light weight and low cost. In other embodiments, the heat dissipating pillar12may be made of copper to enhance thermal conductivity of the heat sink1and implement rapid heat transfer. In other embodiments, an inner wall of the heat dissipating pillar12may be provided with a heat conduction layer with a thickness of 0.1 mm˜0.5 mm to further improve an effect of heat dissipation. Specific surface area of the fins11is 4˜10 times of specific surface area of the heat dissipating pillar12, preferably, 6˜8 times.FIG. 19bis a top view of an LED lamp using the heat sink ofFIG. 19a. As shown, when the LED lamp is a high-power lighting device, an inner diameter r of the bottom of the heat dissipating pillar12may be 10˜15 mm. That is, a distance from the central axis XX of the heat dissipating pillar12to an inner surface of the heat dissipating pillar12may be 10˜15 mm. Because the fins11radially extend from the heat dissipating pillar12, a diameter R from the axis to an outer edges of the fins11may be greater than or equal to 15 mm and less than 20 mm. That is, a distance from the central axis of the heat sink1to an outer edges of the fins11may be greater than or equal to 15 mm and less than 20 mm. From the bottom to the top of the heat sink1, an inner diameter defined by the fins11may be identical or different. In one example, length (R−r) extending from each fin11to the central axis XX of the heat sink1may be constant along a height direction of the heat sink1or may vary along a height direction of the heat sink1. Length of each fin11extending from an inner surface of the heat sink1may be identical or different. That is, length of the fins11may be identical or different in length. Each fin11may extend from the inner surface of the heat sink1in a direction parallel to the central axis of the heat sink1or spirally extend from the inner surface of the heat sink1.

As shown inFIGS. 2, 4 and 5, the base13of the heat sink1has a lower end133located under the base13, i.e. both the lower end133and the light board3are located on the same side. In this embodiment, the lower end133protrudes from the light board3in an axis of the LED lamp. In a using (hanging) status of the light board3being downward, the lower end133is lower than the light board3in position. As a result, the position of the lower end133can protect the LED board3. When collision occurs, the lower end133will collide first to prevent the light board3from colliding. As shown inFIGS. 2 and 4, in another aspect, the base13has a recess132in which the light board3is placed. The recess132is of a cylindrical shape or a substantially cylindrical shape, or a cylindrical platform structure. When the recess132is of a cylindrical shape, a diameter of the cylinder is less than that of the base13. The recess132in the base13is advantageous to reducing a glare effect of the LED lamp and improve direct vision and comfort of users (inner walls of the recess132screen at least part of lateral light from the LED chips311to decrease glare). In some embodiments, the base13may have no recess. In some embodiments, to make both the light board3and the heat sink1have maximum contact area to guarantee a heat dissipation effect, a surface of the base13is a flat plane.

FIG. 20is a cross-sectional view of an LED lamp of an embodiment without the lamp cover4. As shown, in some embodiments, the lower end133is configured to be slanted (relative to the horizon when the LED lamp is being hung). When the slant is flat and straight in a radial direction, an angle between the slant and the horizon is 3˜4 degrees. In other embodiments, the angle is greater than 0 degrees but less than 6 degrees. In some embodiments, when the slant is arced in a radial direction, an angle between a tangent plane of the arced surface and the horizon is 3˜4 degrees. In other embodiments, the angle is greater than 0 degrees but less than 6 degrees. When the lower end133is inclined to a specific angle (e.g. an angle between the lower end133and the outer reflecting surface4302is 120˜180 degrees), it could serve as an extension of the outer reflecting surface4302to perform reflection.

FIG. 21is a perspective view of an LED lamp of an embodiment of the present invention. As shown inFIGS. 2 and 21, another side of the base13of the heat sink1, which is opposite to the lower end133, has a back side134. An end of each fin11extends to connect with the back side134. Thus, At least part of each fin11projects from the LED light board3in an axis. In one example, in an axial direction of the LED lamp, each of the fins11is formed with an extension portion1101between the back side134of the base13and the light board3. The extension portions1101can increase area of heat dissipation of the fins11and improve an effect of heat dissipation. In addition, the extension portion1101does not increase overall height of the LED lamp so as to be advantageous to controlling overall height of the LED lamp.

FIG. 22is a cross-sectional view of the LED lamp of this embodiment. As shown, in this embodiment, the back side134of the base13is slanted. For example, when the LED lamp is being hung, in an inward radial direction, the back side134is upwardly slanted. In another aspect, in a radial direction of the LED lamp toward an axis of the LED lamp, an axial distance from the back side134to the light board3is progressively increased. Such an arrangement is advantageous to convection air is introduced along the back side134to bring out heat of the back side134and prevents the back side134from obstructing air flowing into.

As shown inFIGS. 2 and 5, in a using status, the light board3is downwardly arranged, a position of the lower end133is lower than an end side44of the lamp cover4and the light output surface43. As a result, when packing, transporting or using the LED lamp, if collision occurs, then the lower end133will collide to prevent the lamp cover from colliding to damage the end side44or the light output surface43.

As shown inFIGS. 2 and 5, a receiving space (indent132) is encompassed by the lower ends133for receiving the lamp cover4. Height of the lamp cover4received in the receiving space does not project from the lower end133. Height of the LED lamp mainly includes height of the lamp shell2, height of the heat sink1and height of the lamp cover4. In this embodiment, the lamp cover4does not project from the lower end133, this can control overall height of the lamp and the lamp cover4does not increase overall height of the lamp. In another aspect, the heat sink1additionally increases heat dissipating portion (downward protruding part of the light board3corresponding to the lower end133). In other embodiments, a part of the lamp cover4may project from the lower end133.

As shown inFIGS. 2, 4 and 5, a gap is kept between the end side44and the light board3to form a room8. The room8communicates with both the first air inlet2201of the first heat dissipating channel7aand the second air inlet1301of the second heat dissipating channel7b. Air flows into the room8through the vent41of the end side44and then flows into both the first heat dissipating channel7aand the second heat dissipating channel7b. The room8allows air therein to mix and the mixed air is distributed according to negative pressure (resulting from temperature difference) of both the first and second heat dissipating channels7a,7bso as to make distribution of air more reasonable.

In this embodiment, when a passive heat dissipation manner (fanless) is adopted, the ratio of power (W) of the LED lamp to heat dissipating surface area (square cm) of the heat sink1is 1:20˜30. That is, each watt needs heat dissipating surface area of 20˜30 square cm for heat dissipation. Preferably, the ratio of power of the LED lamp to heat dissipating surface area of the heat sink1is 1:22˜26. More preferably, the ratio of power of the LED lamp to heat dissipating surface area of the heat sink1is 1:25. The first heat dissipating channel7ais formed in the lamp shell2, the first heat dissipating channel7ahas the first air inlet2201at an end of the lamp shell2, and another end of the lamp shell2has the venting hole222. Air flows into the first air inlet2201and flows out from the venting hole222to bring out heat in the first heat dissipating channel7a. The second heat dissipating channel7bis formed in the fins11and the base13and the second heat dissipating channel7bhas the second air inlet1301. Air flows into the second air inlet1301, passes the second heat dissipating channel7b, and finally flows out from the spaces between the fins11to bring out heat radiated from the fins11to air therearound and enhance heat dissipation of the fins11. By both the first and second heat dissipating channels7a,7b, efficiency of natural convection can be increased. This reduces required area of heat dissipation of the heat sink1so as to make the ratio of power of the LED lamp to heat dissipating area of the heat sink1be between 20 and 30. In this embodiment, overall weight of the LED lamp is less than 1.7 Kg. When the LED lamp is provided with power of about 200 W (below 300 W, preferably, below 250 W), the LED chips311are lit up and emit luminous flux of at least 25000 lumens.

As shown inFIG. 1, weight of the heat sink1in this embodiment accounts for above 50% of weight of the LED lamp. In some embodiments, weight of the heat sink1accounts for 55˜65% of weight of the LED lamp. Under this condition, volume of the heat sink1accounts for above 20% of volume of the overall LED lamp. Under a condition of the same thermal conductivity of the heat sink1(i.e. overall heat sink1uses a single material or two different materials with almost identical thermal conductivity), the larger the volume occupied by the heat sink1is, the larger the heat dissipating area which can be provided by the heat sink1is. As a result, when volume of the heat sink1accounts for above 20% of volume of the overall LED lamp, the heat sink1may have more usable space to increase its heat dissipating area. Considering the arrangement space of the power source5, the lamp cover4and the lamp shell2, preferably, volume of the heat sink1accounts for 20%˜60% of volume of the overall LED lamp. More preferably, volume of the heat sink1accounts for above 25˜50% of volume of the overall LED lamp. Accordingly, although the overall size of the LED lamp is limited and the space for receiving the power source5, the lamp cover4and the lamp shell2must be kept, volume of the heat sink1can still be maximized. This is advantageous to design of overall heat dissipation of the LED lamp.

FIG. 23is top view of the heat sink1of the LED lamp of an embodiment. As shown, the heat sink1suffers the above volume limit, so at least part of the fins11are extended outward in a radial direction of the LED lamp with at least two sheets at an interval. By such an arrangement, the fins11in a fixed space can have larger area of heat dissipation. In addition, the extended sheets form support to the fins11to make the fins firmly supported on the base13to prevent the fins11from deflecting.

In detail, as shown inFIG. 23, the fins include first fins111and second fins112. The bottoms of both the first fins111and the second fins112in an axis of the LED lamp connect to the base13. The first fins111interlace with the second fins112at regular intervals. Being projected from the axial direction of the LED lamp, each of the second fins112is to be seen as a Y-shape. Such Y-shaped second fins112can have more heat dissipating area under a condition of the heat sink1occupying the same volume. In this embodiment, both the first fins111and the second fins are evenly distributed on a circumference, respectively. Every adjacent two of the second fins112are symmetrical about one of the first fins111. In this embodiment, an interval between one of the first fins111and adjacent one of the second fins112is 8˜12 mm. In general, to make air flow in the heat sink1smooth and to make the heat sink perform a maximum effect of heat dissipation, intervals between the fins11should be as uniform as possible.

FIG. 27is a main view of an LED lamp of another embodiment. As shown, the fins11are divided into two portions in a radial direction of the LED lamp. The first portion111ais less than the second portion111bin curvature (where the curvature means curvature on an outline of the LED lamp). In other embodiment, the first portion111ais greater than or equal to the second portion111bin curvature.

FIG. 28is a main view of an LED lamp of another embodiment. As shown, two sides of each fin11are provided with heat dissipating bars16. Each of the heat dissipating bar16on a side is located between adjacent two of the heat dissipating bars on the other side. For example, the heat dissipating bars16on two opposite sides do not superpose each other in a projective direction. In this embodiment, a distance between every two of the heat dissipating bars on a side is the same as a distance between every two of the heat dissipating bars on the other side. Such heat dissipating bars16can increase overall surface area of the fins11to make the fins11have more heat dissipating area for heat dissipation for improving performance of heat dissipation of the heat sink1. In this embodiment, to increase surface area of the fins11, surfaces of the fins11may be configured to be of a waved shape.

As shown inFIGS. 11 and 23, at least one of the fins11is divided into two portions in a radial direction of the LED lamp. Thus, a gap between the two portions forms a passage to allow air to pass. In addition, the projecting area of the gap directly exactly corresponds to an area that the LED chips311are positioned on the LED board3to enhance convection and improve an effect of heat dissipation to the LED chips311. In an aspect of limited overall weight of the LED lamp, part of the fins11divided with a gap reduces the amount of the fins11, decreases overall weight of the heat sink1, and provides a surplus space to accommodate other elements. In this embodiment, as shown inFIG. 27, the fins11may have no above gap. That is, each of the fins11is a single piece in a radial direction.

FIG. 24is an enlarged view of portion E inFIG. 23. As shown inFIGS. 23 and 24, the fins11includes first fins111and second fins112. Each of the first fins11is divided into two portions in a radial direction of the LED lamp, i.e. a first portion111aand a second portion111b. The two portions are divided with a gap portion111c. The first portion111ais located inside the second portion111bin a radial direction. Each of the second fins112has a third portion112aand a fourth portion112bextending therefrom. The fourth portions112bare located radially outside the third portions112ato increase space utilization and make the fins have more heat dissipating are for heat dissipation. As shown inFIG. 24, the third portion112ais connected to the fourth portion112bthrough a transition portion113. The transition portion113has a buffer section113aand a guide section113b. At least one or both of the buffer section113aand the guide section113bare arced in shape. In other embodiment, both the buffer section113aand the guide section113bare formed into an S-shape or an inverted S-shape. The buffer section113ais configured to prevent air radially outward flowing along the second fins112from being obstructed to cause vortexes. Instead, the guide section113bis configured to be able to guide convection air to radially outward flow along the second fins112without interference (as shown idFIG. 25).

As shown inFIG. 24, one of the second fins112includes a third portion112aand two fourth portions112b. The two fourth portions112bare symmetrical about the third portion112a. In other embodiments, one of the second fins112may include a third portion112aand multiple fourth portions112bsuch as three or four fourth portions112b(not shown). The multiple fourth portions112bof the second fin112are located between two first fins111.

As shown inFIG. 24, a direction of any tangent of the guide section113bis separate from the gap portion111cto prevent convection air from flowing into the gap portion111cthrough the guide portion113b, such that the poor efficiency of heat dissipation caused by longer convection paths is able to be avoided as well. Preferably, a direction of any tangent of the guide section113bis located radially outside the gap portion111c. In other embodiments, a direction of any tangent of the guide section113bis located radially inside the gap portion111c.

As shown inFIG. 26, in another embodiment, a direction of any tangent of the guide section113bfalls in the gap portion111cto make convection more sufficient but convection paths will increase.

As shown inFIG. 21, at least partially of fin11has a protrusion1102projecting from a surface of the fin11. The protrusions1102extend along an axis of the LED lamp and are in contact with the base13. A surface of the protrusion1102may selectively adopt a cylindrical shape or a regular or an irregular polygonal cylinder. The protrusions1102increase surface area of the fins11to enhance efficiency of heat dissipation. In addition, the protrusions1102also form a support effect to the fins11to prevent the fins11from being inflected in manufacture. In some embodiments, a single fin11is divided into two portions in a radial direction of the LED lamp. Each portion is provided with at least one protrusion1102to support the two portions. In this embodiment, the protrusion1102is located at an end portion of each fin11in a radial direction of the LED lamp, for example, at end portions of the first portions111a,111b(the ends near the gap portion111c).

In some embodiments, when each fin11is a single piece without the gap portion, the protrusion1102may also be disposed on a surface of each fin11(not shown) to increase surface area of heat dissipation of the fins11and have a support effect to the fins11to prevent the fins11from being inflected in manufacture.

FIG. 29is a bottom view of the LED lamp ofFIG. 1without the lamp cover4.FIG. 30is an enlarged view of portion A inFIG. 29. As shown inFIGS. 29 and 30, the heat sink1is disposed outwardly of the sleeve21, and the power source5is disposed in the inner space of the sleeve21. A distance is kept between distal ends of the fins11and the sleeve21. Accordingly, the sleeve21which has been heated to be thermally expanded will not be pressed by the fins11to be damaged. Also, heat from the fins11will not be directly conducted to the sleeve21to adversely affect electronic components of the power source5in the sleeve21. Finally, air existing in the distance between the fins11and the sleeve21of the lamp shell2(as shown inFIG. 3) possesses an effect of thermal isolation so as to further prevent heat of the heat sink1from affecting the power source5in the sleeve21. In other embodiments, to make the fins11have radial support to the sleeve21, distal ends of the fins11may be in contact with an outer surface of the sleeve21and another part of the fins11are not in contact with the sleeve21. Such a design may be applied in the LED lamp shown inFIG. 29. As shown inFIG. 29, the light board3includes a third aperture32for exposing both the first air inlet2201of the first heat dissipating channel7aand the second air inlet1301of the second heat dissipating channel7b. In some embodiments, to rapidly dissipate heat from the power source5, the ratio of cross-sectional area of the first air inlet2201to cross-sectional area of the second air inlet1301is greater than 1 but less than or equal to 2. In some embodiments, to rapidly dissipate heat from the power source5, the ratio of cross-sectional area of the second air inlet1301to cross-sectional area of the first air inlet2201is greater than 1 but less than or equal to 1.5.

As shown inFIGS. 21 and 22, the innermost of the fins11in a radial direction of the LED lamp is located outside the venting hole222in a radial direction of the LED lamp. In one example, an interval is kept between the innermost of the fins11in a radial direction of the LED lamp and the venting hole222in a radial direction of the LED lamp. As a result, heat from the fins11flowing upward will not gather to the venting hole222to keep an interval with the venting hole222. This avoids heat making air around the venting hole222heat up to affect convection temperature speed of the first heat dissipating channel7a(the convection speed depends upon a temperature difference between two sides of the first heat dissipating channel7a, when air temperature near the venting hole222rises, the convection speed will correspondingly slow-down).

FIG. 31is a cross-sectional view of an LED lamp of an embodiment.FIG. 32is an enlarged view of the LED lamp of portion C inFIG. 31. As shown, the heat sink1includes the fins11and the base13. The base13has a projecting portion135which is downwardly formed in an axial direction of the LED lamp. The projecting portion135protrudes from the light board3in an axial direction of the LED lamp. The lowermost position of the projecting portion135(lower end133) is substantially flush with the light output surface43of the light cover4(in an axial direction of the LED lamp) or the lowermost position of the projecting portion135slightly protrudes from the light output surface43. For example, the lowermost position of the projecting portion135protrudes from the light output surface43by about 1˜10 mm to keep overall height of the heat sink1in the LED lamp unvarying or slightly increase volume for obtaining more heat dissipating area of both the fins11and the base13.

The projecting portion135in this embodiment is configured to be annular and a concave structure is defined by both the projecting portion135and the base13for receiving and protecting both the light source and the light cover4. Also, the concave structure can perform an effect of anti-flare (because the concave structure shades lateral light from the light source).

As shown inFIG. 32, the base13has a first inner surface136and the lamp cover4has a peripheral wall45. When the lamp cover4has been correctly installed to the LED lamp, the first inner surface136corresponds to the peripheral wall45(the outer wall of the lamp cover4). A gap is kept between the first inner surface136and the peripheral wall45to prevent the lamp cover4from thermally expanding and being pressed by the first inner surface136to be damaged. The gap between the first inner surface136and the peripheral wall45can reduce or avoid the abovementioned pressing. In other embodiments, a part of the peripheral wall45is in contact with the first inner surface136to radially support the lamp cover4by the first inner surface136. Gaps are still kept between the other parts of the peripheral wall45and the first inner surface136.

As shown inFIG. 32, the first inner surface136is configured to be a slant and an angle is formed between the first inner surface136and the light board3. The angle may be an obtuse angle. Thus, when the lamp cover4is thermally expanded and its peripheral wall45presses the slant, the pressure exerted from the first inner surface136to an outer portion of the lamp cover4is divided into a downward component and a horizontal component to reduce horizontal pressure to the lamp cover4(horizontal pressure is a main cause of damage). In other embodiments, the peripheral wall45may abut against the first inner surface136(not shown) so as to support or limit the lamp cover4. Also, because the first inner surface136is a slant, damage of the lamp cover4resulting from pressure of thermal expansion can be decreased. An end portion of the peripheral wall45may abut against the first inner surface136to decrease contact area between overall peripheral wall45and the base13and avoid excessive thermal conduction.

As shown inFIG. 32, the base further includes a second inner surface137and the lamp cover4has a peripheral wall45. A gap is kept between the peripheral wall45and the first inner surface136. An end portion of the peripheral wall45abuts against the second inner surface137. An angle between the first inner surface136and the light board3is less than an angle between the second inner surface137and the light board3. That is, the second inner surface137is flatter than the first inner surface136. As a result, when the peripheral wall45abuts against the second inner surface137and the lamp cover4is thermally expanded, the horizontal pressure from the second inner surface137to the lamp cover4becomes less. In this embodiment, the angle between the second inner surface137and the light board3is between 120 degrees and 150 degrees. If the angle is too big, then radial support to the lamp cover4in a radial direction of the LED lamp will not be sufficient enough. While if the angle is too small, not only can the horizontal pressure exerted to the lamp cover4which has been thermally expanded not be reduced, but also limiting and supporting the lamp cover4in an axial direction of the LED lamp cannot be obtained. When the angle falls in the above range, a great balance can be accomplished. In other embodiments, both the second inner surface137and the first inner surface136may be curved. A distance difference between the second inner surface137and the axis of the LED lamp and between the first inner surface136and the axis of the LED lamp downward progressively increases. However, in general, the second inner surface137is flatter than the first inner surface136.

As shown inFIG. 33, the end portion of the peripheral wall45is provided with protruding plates451upward extending from the peripheral wall45at regular intervals. The protruding plates451are the parts that the end portion of the peripheral wall45is in actual contact with the second inner surface137. The protruding plates451can reduce contact area between the peripheral wall45and the base13to prevent heat of the heat sink1from being conducted to the lamp cover4to make the lamp cover4overheat.

As shown inFIGS. 31 and 32, a gap is formed between the peripheral wall45and the base13and the base13is formed with a hole. A side of the hole communicates with the gap and the other side corresponds to the fins11. In one example, air may flow into the gap, passes the hole and reaches the fins11to enhance convection. The convection path as shown by the arrow inFIG. 32may form a fourth heat dissipating channel7dof the LED lamp in this embodiment. Because the protruding plates451are arranged on the peripheral wall45at regular intervals, air can pass through intervals between the protruding plates451(as shown inFIG. 33) to accomplish the abovementioned convection. As shown inFIGS. 34 and 35, in another embodiment, the fourth heat dissipating channel7dmay also be disposed at other positions as long as a region between a lower portion of the LED lamp and the fins11are communicated. For example, a through hole315is formed between adjacent two LED chip sets31. At this time, the lamp cover4may be configured to be separate, i.e. include multiple parts to separately cover different LED chip sets31. The through hole315is located between two parts of the lamp cover4to make the through hole315communicate with the lower portion of the LED lamp and communicate with the spaces between the fins11.

The heat sink1in this embodiment is an integrated structure so as to advantageous to reducing thermal resistance between the fins11and the base13. In other embodiments, in order to be convenient to be machined and formed, the fins11and the base13may also be configured to be detachable.

In this embodiment, different positions of the fins11have different temperature. For example, when the LED lamp is working, a portion near the LED chips311is around 80° C., but the temperature of the upper portion (the opposite portion to the portion near the LED chips311) of the fins11would slightly decrease. With different distribution of temperature inside the fins11, the heat dissipation efficiency of the fin11is defined as a percentage of the post-dissipation temperature to the average temperature of the fins11. The heat dissipation efficiency of the fins11can be calculated by thermal conductivity and size. The heat dissipation efficiency of the fins11is relative with thermal conductivity, thickness, width and height of the fins11.

In this embodiment, to improve heat dissipation efficiency of the fins11, thickness of each fin11is configured to be 0.8˜2 mm, preferably, 1˜1.5 mm. The ratio of thickness to length of the fin11is not less than 1:80. Preferably, the ratio of thickness to length of the fin11is not less than 1:70. More preferably, the ratio of thickness to length of the fin11is not less than 1:60˜80. According to the effect of heat dissipation of the fins11, a balance can be obtained between overall weight of the heat sink1and heat dissipating area to make the fins have better efficiency. The length of the fin11means height in an axial direction of the LED lamp. The ratio of width to length of the fin11in this embodiment is configured to be greater than 1:1.5, preferably, the ratio is greater than 1:1.3 to make thermal conductivity of the fins11better and improve efficiency of the fins11. The length of the fin11means height in an axial direction of the LED lamp, and the width means length of the fin11in a radial direction of the ELD lamp. When the fins11are in irregular directions, width of the fins11may use their average value or a sum of a half of the maximum value of width and a half of the minimum value of width, and length of the fins11may use their average value or a sum of a half of the maximum value of length and a half of the minimum value of length.

where H stands for thermal conductivity, its unit is W/(m2·° C.);

V stands for flowing speed of convection air; and

L stands for length of the fin in the convection direction.

It can be seen from the above formula that thermal conductivity is affected by arrangement of heat dissipating surface of the fins11much more than other factors when considering at least part of heat of the fins11which is dissipated by convection. In addition, when the fins11are transferring heat, their thickness (cross-sectional area) is an important factor, too. Temperature of downward flowing air would rise and its cooling ability correspondingly decreases. Thus, under the fins11with the same area, if the fins11are configured to have shorter length and longer width in the airflow direction, then the amount of heat dissipation would increase. Besides, under the same heat dissipating area, the above embodiment may control height of the fins11to make the fins11have more area near the LED chips311and enhance thermal conduction from the LED chips311to the fins11. Thickness of the fin11may also affect efficiency of the fins11. The larger the thickness of the fin11is, the higher the efficiency is, but a balance of weight and heat dissipating area should also be considered. In sum, the ratio of thickness to length of the fin11is configured to be not less than 1:80, and the ratio of width to length of the fin11is configured to be greater than 1:1.5.

FIGS. 36a˜36mare schematic views of some embodiments of the heat sink10, which can be applied in LED lamps to replace the heat sink1shown inFIG. 1.

As shown inFIG. 36a, which shows a first embodiment of the heat sink10. The heat sink10includes first fins101and second fins102. The heat sink10is defined with a first circumference R1and a second circumference R2, which are projected onto the base130. The first circumference R1is less than the second circumference R2. On the base130, the first fins101extend into a cylindrical room (the part for receiving the sleeve21, the cylindrical room mentioned in the following embodiments is the same as this) but do not exceed the second circumference R2. For example, the first fins101extend from the cylindrical room right to the first circumference R1. The second fins102extend to the first circumference R1but do not exceed the second circumference R2, e.g. just extend to the second circumference R2. In a radial direction, both the first fins101and the second fins102are interlacedly arranged. Each adjacent of the second fins102is symmetrically arranged about one of the first fins101. Intervals are formed between adjacent two of the first fins101and the second fins102for allowing air to pass and prolonging paths that air flows through the first and second fins101,102to increase the amount of heat exchange between the fins101,102and the airflow.

As shown inFIG. 36b, which shows a second embodiment of the heat sink10. The heat sink in this embodiment differs from the first embodiment by the heat sink10further including division fins108. The division fins108radially extend from an outer surface of the cylindrical room to the second circumference R2. The division fins108are interlacedly arranged with the first fins101within the first circumference R1and are interlacedly arranged with the second fins102between the first circumference R1and the second circumference R2. As a result, each of the division fins108is symmetrically between two of the first fins101and two of the second fins102.

As shown inFIG. 36c, which shows a third embodiment of the heat sink10. The heat sink in this embodiment differs from the second embodiment by the heat sink10further including third fins103. A third circumference R3is defined by being projected onto the base103of the heat sink10. And the third circumference R3is greater than the second circumference R2. On the base103, the first fins101extend from the cylindrical room to the first circumference R1, the second fins102extend from the first circumference R1to the second circumference R2, and the third fins103extend from the second circumference R2to the third circumference R3. In a radial direction, the second fins102and the third fins103are interlacedly arranged. Each two third fins103are symmetrically arranged about one of the second fins102.

The fins of the third embodiment may be further expanded to the nth fin, where n is an integer greater than two. For example, the first circumference R1through the nth circumference with gradually getting bigger are defined on the base130. The first fins101extend from the cylindrical room to the first circumference R1. The nth fin extends from the (n−1)th circumference to the nth circumference. In a radial direction, the (n−1)th fin and the nth fin are interlacedly arranged. Each two nth fins are symmetrically arranged about one of the (n−1)th fins. In addition, from first fin101to the nth fin, at least part thereof overlap with the light board3(a projection in an axial direction of the LED board3) to ensure a direct thermal conduction path existing between the LED light board3and the fins.

As shown inFIG. 36c, the nth fin and the (n−1)th fin are interlaced but do not overlap. An outer edge of the (n−1)th fin does not exceed the (n−1)th circumference. The nth fin extends from the (n−1)th circumference. For example, an outer edge of the second fin102does not exceed the second circumference R2, and the third fin103extends from the second circumference R2and does not exceed the third circumference R3.

As shown inFIG. 36d, in the fins of the third embodiment, the nth fin and the (n−1)th fin may interlacedly overlap. An outer edge of the (n−1)th fin exceeds the (n−1)th circumference but does not reach the nth circumference. The nth fin extends from the (n−1)th circumference. For example, an outer edge of the second fin12exceeds the second circumference but does not reach the third circumference R3. The third fin13extends from the second circumference R2.

In the embodiment shown inFIGS. 1 and 2, an outer edge of each fin11is arced. In other embodiments, an outer edge of the fin may be waved, straight or stepped.

As shown inFIG. 36e, which shows a fourth embodiment of the heat sink10. The fourth embodiment differs fromFIG. 1by the fins of the heat sink1. For example, an outer edge of the first fin101is perpendicular to the base130. Thus, observing the first fins101from a viewpoint in a direction perpendicular to the axis, the fins present rectangular or square instead of upward tapered curved outer edges. The rectangular first fins101, under the limit of the same height and width, can effectively increase area of the first fins101and enhance thermal exchange with airflow.

As shown inFIG. 36f, in a specific embodiment, the fins of the heat sink1include the first fin101through the nth fin. Each of the first fin through the nth fin has holes101apenetrating through two sides of the fin. For example, the first fin shown inFIG. 36fhas the holes101athrough two sides thereof. The holes101athrough two sides if the fin can promote air to flow to enhance heat dissipation and reduce weight of the heat sink1.

As shown inFIG. 36g, in a specific embodiment, the fins of the heat sink10include the first fin101through the nth fin. They are configured to have a two-stage step. The first stage1011extends from the base130and the second stage1012extends from the first stage1011. Length of the first stage1011in a radial direction of the LED lamp is greater than that of the second stage1012in a radial direction of the LED lamp. Height of the first stage1011in an axial direction of the LED lamp is lower than that of the second stage1012in an axial direction of the LED lamp. Thus, observing the first fins101from a viewpoint in a direction perpendicular to the axis, the fins present stepped. Such a shape guarantees fin area in the lower portion, which is sufficient to conduct heat from the working LED chips311. The upper portion uses both radiation and convection. As a result, fin area can be properly reduced to decrease weight.

As shown inFIG. 36h, which shows a fifth embodiment of the heat sink10. The heat sink10of the fifth embodiment is based on the fourth embodiment. It further includes second fins102. An outer edge of the second fin102is perpendicular to the base130to make the second fin present rectangular or square. In addition, height of the second fin102on the base130is less than height of the first fin101and the second fins102interlace with the first fins101. Thus, the second fins102can increase area of thermal exchange with airflow. However, because its height is short, thermal radiation exchange between the first fins101and the second fins102can be reduced. In this embodiment, if the total amount of both the first fins101and the second fins102is the same as the amount of the fins on the fourth embodiment (i.e. under the condition of the same amount), then this embodiment is more advantageous to overall weight reduction of the heat sink10and can decrease thermal radiation exchange between the first fins101and the second fins102.

As shown inFIG. 36i, which shows the sixth embodiment of the heat sink10. The heat sink10of the sixth embodiment is based on the above embodiment. It further includes an outer support wall106and an inner support wall105. The outer support wall106connects to an outer edge of the first fins101and the inner support wall105connects to an inner edge of the first fins101to prevent the first fins101from inflecting. As shown inFIG. 36i, observing the heat sink10from an upper viewpoint, both the outer support wall106and the inner support wall105present annular to make the first fin101radially connected. Both the outer support wall106and the inner support wall105may connect to the base130or perpendicularly extend from an upper surface of the base130. Both the outer support wall106and the inner support wall105may also merely connect to the first fins101and keep a distance with the outer surface of the base130. In an axial direction, height of both the outer support wall106and the inner support wall105is less than height of the first fins11to maintain smooth axial airflow. Either of the outer support wall106and the inner support wall105may be selected to be used. It is unnecessary to use both the outer support wall106and the inner support wall105. As shown inFIG. 36j, both the outer support wall106and the inner support wall105may be configured to be segmentalized, i.e. the outer support wall106as an example, it is divided into multiple arced segments1061at regular or irregular intervals on a single circumference. Each arced segment1061connects at least two first fins101to further reduce adverse influence to convection.

As shown inFIG. 36k, which shows a seventh embodiment of the heat sink10. The heat sink10of the seventh embodiment is based on the above embodiment to modify a shape of the first fins101. In the seventh embodiment, the first fins101includes a first portion101a, a second portion101band a connecting portion101c. Both the first portion101aand the second portion101bradially extend to connect to each other through the connecting portion101c. The first portion101aextends from an outer surface of the cylindrical room. The second portion101bconnects to the first portion101athrough the connecting portion101cto further extend outward. The connecting portion101cis not parallel to the radial direction. In one embodiment, the connecting portion101cextends approximately along a circumferential direction or a direction perpendicular to a radial direction to make the first portion101aand the second portion101bare interlaced arranged in a radial direction without being located on a radial extending line. The connecting portion101ccan increase area of the first fins11to improve thermal exchange amount between airflow and the first fins11. In addition, the connecting portion101calso prevent the first fins from being inflected.

As shown inFIGS. 36land 36m, which shows an eighth embodiment of the heat sink10. The heat sink10of the eighth embodiment is based on the above embodiment to modify a shape of the first fins101. In the eighth embodiment, multiple concentric circles are defined on the base130and the concentric circles perpendicularly extend from the base130.

InFIG. 36l, each of the first fins101on a corresponding one of the concentric circles is continuous, i.e. the first fins101present continuously annular. Each concentric circle is disposed with one first fin101.

InFIG. 36m, each of the first fins101on a corresponding one of the concentric circles is discontinuous, i.e. the first fins101present discontinuously annular. A gap is retained between two adjacent segments of the first fin101on the same concentric circle to allow air to flow radially.

In some embodiments, the heat sink has a central axis XX. A plane A-A with the central axis XX as a normal and the central axis XX intersect at an intersection91in the cylindrical room of the heat sink. In some embodiments, the distance from the central axis XX to edges of the fins11along the plane A-A is greater than zero as shown inFIGS. 37a-37d, InFIG. 37a, the intersection91serves as a center, distance D1as a radius, create a virtual circle on the plane A-A (the broken line shown inFIG. 37a). The heat sink1has at least one fin11. The virtual circle abuts against an edge of the fin11. When the heat sink1has a plurality if fins11, a constant distance D1exists from edges of the fins11to the central axis XX of the heat sink1. The virtual circle abuts against edges of all the fins11. In some embodiments, the heat sink1has multiple fins11. The distances D1and D2from edges of at least two of the fins11to the central axis XX of the heat sink1are different. Distance D1is less than distance D2. The intersection91serves as a center, the shorter distance D1as a radius, create a virtual circle on the plane A-A (the broken line shown inFIG. 37b). The virtual circle does not abut against edges of the fins11with the distance D2as shown inFIG. 37b.

In some embodiments, the heat sink1has multiple fins11. All distances D1, D2, D3. . . Dn (only D1-D3are shown inFIG. 37c) from edges of the fins11to the central axis XX are different. Distance D1is less than distance D2which is less than distance D3. The intersection91serves as a center, the shortest distance D1as a radius, create a virtual circle on the plane A-A (the broken line shown inFIG. 37c). The virtual circle does not abut against edges of the fins11which are greater than the shortest distance D1as shown inFIG. 37c.

In some embodiments, the heat sink1has multiple fins11. All distances D1, D2, D3from edges of the fins11to the central axis XX are different. Distance D1is less than distance D2which is less than distance D3. The intersection91serves as a center, distances D1, D2, D3as radiuses, create three virtual circles on the plane A-A (the broken line shown inFIG. 37d). Part of the virtual circles do not abut against parts of edges of the fins11. Part of the virtual circles pass through parts of the fins11as shown inFIG. 37d. The virtual circle created on the plane A-A with distance D1as a radius does not abut against the fins with distances greater than distance D1. The virtual circle created on the plane A-A with distance D2as a radius, the fins11with a passing distance less than D2do not abut against the fins with distances greater than D2.

FIGS. 38a˜38iare top views of some embodiments of the heat sink1, which replace the heat sink1inFIG. 1for detailed description. As shown inFIGS. 1 and 38a, the heat sink1includes heat dissipating units and a base13. Each heat dissipating unit extends from the base13along an axial direction of the LED lamp. A specific embodiment of the heat dissipating units are fins11. The heat dissipating units are radially arranged on the base13. A root of each heat dissipating unit is connected to the base13. A cylindrical room14is defined by inner edges of the heat dissipating units. The room14is used for receiving the sleeve21. When the LED lamp is working, heat from the light board3is conducted by the base13to the heat dissipating units and finally from the heat dissipating units to external air to enhance heat dissipation. The lamp shell1connects to the heat sink1and approximately connects to upper edges of the heat dissipating units. Portions at least near the axis of the LED lamp of upper edges of the heat dissipating units are flatly cut off along a radial direction to define a flat connecting plane. A corresponding fastener can be arranged between the lamp shell2and upper edges of the heat dissipating units to fasten a lower end of the lamp shell2to the connecting plane to connect the heat sink1.

As shown inFIGS. 1, 2 and 38a, a first cross-section A1is defined on the connecting plane along a radial direction of the LED lamp. A second cross-section A2is defined on a connecting surface between the heat sink1and the light board3along a radial direction of the LED lamp. In an embodiment, the amount of the heat dissipating units being projected onto the first cross-section A1in an axial direction of the LED lamp is less than the amount of the heat dissipating units being projected onto the second cross-section A2in an axial direction of the LED lamp. That is, in an axial direction, because air flows upward, the heat dissipating units should be prevented from being obstructed by the lamp shell2as much as possible. This makes upper edges of most heat dissipating units exposed to air to form heat dissipating channels which are not obstructed by the lamp shell2for improving convection effect of the heat dissipating units. In another aspect, by means of the amount of the heat dissipating units being projected onto the first cross-section A1in an axial direction of the LED lamp being less than the amount of the heat dissipating units being projected onto the second cross-section A2in an axial direction of the LED lamp can accomplish the above technical effect. In an aspect of area of axial projection of the heat dissipating units, by means of the amount of the heat dissipating units being projected onto the first cross-section A1in an axial direction of the LED lamp being less than the amount of the heat dissipating units being projected onto the outside of the first cross-section A1in an axial direction of the LED lamp can accomplish the above technical effect.

As shown inFIG. 38a, multiple annular zones are defined on the heat sink1. Each annular zone owns different amount of the heat dissipating units from the others'. For example, the amount of the heat dissipating units owned by an inner annular zone is less than the amount of the heat dissipating units owned by an outer annular zone. The amount or area of the annular zones overlapping with the projection of the first cross-section A1in an axial direction of the LED lamp is less than the amount or area of the annular zones overlapping with the projection of the second cross-section A2in an axial direction of the LED lamp.

In detail, as shown inFIG. 38b, the heat dissipating units may include multiple first heat dissipating units15and multiple second heat dissipating units16(where both the first heat dissipating units15and the second heat dissipating units16are different from both the first fins111and the second fins112inFIGS. 23 and 24in naming principle and category). InFIG. 38b, the first heat dissipating units15are radially inner fins and the second heat dissipating units16are radially outer fins. The first heat dissipating units15are mainly projected onto inner annular zones and the second heat dissipating units16are mainly projected onto outer annular zones. An outer edge of each first heat dissipating units15radially branches away into two second heat dissipating units16(the first heat dissipating units15and the second heat dissipating units16may be continued or discontinued, the latter means a radial gap is retained between the first heat dissipating units15and the second heat dissipating units16) to make the second heat dissipating units16is greater than the first heat dissipating units15in number. In addition, the first cross-section A1is projected onto inner annular zones and the second cross-section A2is projected onto outer annular zones, so the first heat dissipating units15is projected onto inner annular zones in an axial direction of the LED lamp and the second heat dissipating units16is projected onto outer annular zones in an axial direction of the LED lamp. As a result, the amount or area of the first heat dissipating units15being projected onto the first cross-section A1in an axial direction of the LED lamp is less than the amount or area of the second heat dissipating units16being projected onto the second cross-section A2in an axial direction of the LED lamp.

As shown inFIGS. 38cand 38d, when the first heat dissipating units15is greater than the second heat dissipating unit16in thickness, because of radial arrangement, a distance between adjacent two of the first heat dissipating units15near the axial axis of the LED lamp is less than a distance between adjacent two of the second heat dissipating units16away from the axial axis of the LED lamp. When thickness of the first and second heat dissipating unit15,16is properly configured, any circumferential perimeter (sum of ΔX1) of the first cross-section A1of the first heat dissipating unit15is equal to any circumferential perimeter (sum of ΔX2) of the second cross-section A2of the second heat dissipating unit16. The circumferential perimeter means a total length of arcs of any virtual circles with the axis of the LED lamp as a center cutting the first heat dissipating units15or the second heat dissipating units16.

In detail, both the first and second heat dissipating units15,16are fins which are radially distributed in the heat sink1. The heat sink1is outward divided into a first annular zone C1and a second annular zone C2. The heat sink1further includes a cylindrical room14inside the first annular zone C1. The cylindrical room14is mainly used for receiving part of the power source board and providing a heat dissipating channel. A virtual circle with the axis of the heat sink1as the center is created. When the sum of arcs which are formed by the virtual circle falling in the first annular zone C1to cut the fins is X1(sum of ΔX1), and the sum of arcs which are formed by the virtual circle falling in the second annular zone C2to cut the fins is X2(sum of ΔX2), then X1<X2. The ratio of the sum of arcs which are formed by the virtual circle to cut the fins to the circumferential perimeter of the virtual circle may be 06˜0.2. This makes the fins have sufficient cross-sectional area to perform thermal conduction and maintain distances between the fins to keep sufficient sizes of convection channels. Also, surface area of the fins is sufficient enough under the same weight.

Furthermore, if the fins in the first annular zone C1needs larger cross-sectional area to perform thermal conduction, for example, density of the LED chips311of the LED board3projected onto the first annular zone C1is greater than density of projection on the second annular zone C2(where the term “density” means the number of the LED chips311in unit area of the annular zone), and the ratios of X1and X2to the perimeter of the virtual circle are Ra1and Ra2, respectively, then it can be configured that Ra1>Ra2or X1>X2to make the fins in the first annular zone C1have larger cross-sectional area to perform thermal conduction and maintain distances between the fins to keep sufficient sizes of convection channels.

Contrarily, if the fins in the second annular zone C2needs larger cross-sectional area to perform thermal conduction, for example, density of the LED chips311of the LED board3projected onto the first annular zone C1is greater than density of projection on the second annular zone C2, and the ratios of X1and X2to the perimeter of the virtual circle are Ra1and Ra2, respectively, then it can be configured that Ra1<Ra2or X1<X2to make the fins in the second annular zone C2have larger cross-sectional area to perform thermal conduction and maintain distances between the fins in the first annular zone C1to keep sufficient sizes of convection channels.

If density of the LED chips311of the LED board3projected onto the first annular zone C1is equal to density of projection on the second annular zone C2, then it can be configured that Ra1=Ra2or X1=X2to make the fins in the first annular zone C1is similar to the second annular zone C2in efficiency of thermal conduction to avoid high temperature difference in the light board3.

As shown inFIG. 38e, in some embodiments, outer edges of merely some first heat dissipating units15radially branch away into two second heat dissipating units16or the first heat dissipating units15and the second heat dissipating units16are individually disposed with different distribution density. The heat sink1inFIG. 38f, the amount or area of the first heat dissipating units15being projected onto the first cross-section A1in an axial direction of the LED lamp is greater than the amount or area of the second heat dissipating units16being projected onto the second cross-section A2in an axial direction of the LED lamp. Identically, in a condition of multiple annular zones, the amount or area of the first heat dissipating units15being projected onto inner annular zones in an axial direction of the LED lamp would be greater than the amount or area of the second heat dissipating units16being projected onto outer annular zones in an axial direction of the LED lamp.

Identically, inFIG. 38f, when the first heat dissipating units15is less than the second heat dissipating units16in thickness, the interval between adjacent two of the first heat dissipating units15may be greater than the interval between adjacent two of the second heat dissipating units16. When thickness of the first and second heat dissipating units15,16is properly configured, any circumferential perimeter of the first cross-section A1of the first heat dissipating units15is equal to any circumferential perimeter of the second cross-section A2of the second heat dissipating units16.

As shown inFIG. 38f, in one embodiment, outer edges of merely some first heat dissipating units15radially branch away into two second heat dissipating units16or the first heat dissipating units15and the second heat dissipating units16are individually disposed with one-to-one correspondence in a single radial line to make the amount of the first heat dissipating units15being projected onto the first cross-section A1in an axial direction of the LED lamp be equal to the amount of the second heat dissipating units16being projected onto the second cross-section A2in an axial direction of the LED lamp. Identically, in a condition of two or more annular zones, the amount or area of the first heat dissipating units15being projected onto inner annular zones in an axial direction of the LED lamp would be equal to the amount or area of the second heat dissipating units16being projected onto outer annular zones in an axial direction of the LED lamp.

As shown inFIG. 38f, in one embodiment, when the first heat dissipating units15are equal to the second heat dissipating units16in thickness, and the interval between adjacent two of the first heat dissipating units15is equal to the interval between adjacent two of the second heat dissipating units16, any circumferential perimeter of the first cross-section A1of the first heat dissipating units15is equal to any circumferential perimeter of the second cross-section A2of the second heat dissipating units16.

As shown inFIGS. 38aand 38g, the amount of the annular zones may be more than two, for example, the heat sink1further includes a third annular zone C3outside the second annular zone C2. When the sum of arcs which are formed by the virtual circle falling in the third annular zone C3to cut the fins is X3(ΔX3), and X1<X2<X3. When the ratios of X1, X2and X3to the perimeter of the virtual circle are Ra1, Ra2and Ra3, respectively, then Ra1=0.06˜0.13, Ra2=0.1˜0.18, Ra3=0.12˜0.16, and all the values of Ra1, Ra2and Ra3fall in the range of 0.06˜0.2. This makes the fins have sufficient cross-sectional area to perform thermal conduction and maintain distances between the fins to keep sufficient sizes of convection channels. Also, surface area of the fins is sufficient enough under the same weight.

As shown inFIGS. 11, 38hand38i, a chip mounting zone is defined on the light board3(a zone on which the LED chips311are located). The LED chips311are mounted on the chip mounting zone. At least part of the chip mounting zone falls in a projection of the second annular zone C2or the third annular zone C3. In detail, the chip mounting zone overlaps the heat sink1in outer annular zones as much as possible so as to make the corresponding fins (the first heat dissipating units111or the second heat dissipating units112) located on an outer edge of the base13to obtain better cooling effect and be able to correspond to more heat dissipating units (outer heat dissipating units are greater than inner heat dissipating units in number). In an embodiment, at least 80% of the chip mounting zone falls in the projection(s) of the second annular zone C2and/or the third annular zone C3. Preferably, all the chip mounting zone falls in the projection(s) of the second annular zone C2and/or the third annular zone C3as shown inFIG. 38i.

When the fins are radially arranged on the heat sink1with even thickness, the number of the fins cut by the virtual circle falling in the first annular zone C1is N1, the number of the fins cut by the virtual circle falling in the second annular zone C2is N2, and N1<N2, X1<X2would be substantially implemented. Identically, the third annular zone C3is located outside the second annular zone C2, the number of the fins cut by the virtual circle falling in the third annular zone C3is N3, and N1<N2<N3, X1<X2<X3would be substantially implemented. Under such an arrangement, the chip mounting zone can still be arranged as shown inFIG. 38h.

FIG. 39is a top view of an embodiment of the heat sink1. As shown inFIG. 39, the heat sink1includes multiple first heat dissipating units15and multiple second heat dissipating units16(where both the first heat dissipating units15and the second heat dissipating units16are different from both the first fins111and the second fins112inFIGS. 23 and 24in naming principle and category). Both the first heat dissipating units15and the second heat dissipating units16are fins. Each first heat dissipating units15includes a first fin15aradially arranged on the heat sink1and a radial first channel15b. The first channel15bis a gap between two first heat dissipating units15a. Multiple annular zones are outward defined on the heat sink1, namely, the first annular zone C1, the second annular zone C2and the third annular zone C3. Parts of the first channel111b, which are located in different annular zones, have different widths. In the same annular zone, the first channel15bin an outer portion is greater than the first channel15bin an inner portion in width.

As shown inFIG. 39, the first heat dissipating units in different annular zones may adopt different configurations of density. The first fins of the first heat dissipating units15may extend in between at least two annular zones to make the first heat dissipating units interlacedly arranged and the first channel15bin different annular zones have different widths. Alternatively, the first fins extend in between at least two annular zones and are discontinuous at a junction of the two annular zones.

As shown inFIG. 39, each second heat dissipating units16includes two second fins16aand a second channel16bformed therebetween. An end of the second channel16b, which is toward the central axis of the heat sink1is discontinuously open or closed. The first heat dissipating units15and the second heat dissipating units16may be located in different annular zones, and the annular zone in which the second heat dissipating units16is located is outside the annular zone in which the first heat dissipating units15is located.

As shown inFIG. 39, when an end of the second channel16b, which is toward the central axis of the heat sink1is closed, two second fins16may extend to an outer edge of the first fin15. Both the closed end of the second fins16and an outer edge of the first fin are located on the same radial line but are discontinuous to form a gap as an additional channel.

LEDs generates heat while they are emitting. A key parameter in considering of thermal conduction of LEDs is thermal resistance. The smaller the thermal resistance is, the better the thermal conduction is. Primarily, factors of thermal resistance include length of conduction path, conduction area and thermal conductivity of a thermo-conductive material. It can be expressed by the following formula:
Thermal resistance=length of conduction pathL/(conduction areaS*thermal conductivity)

That is to say, the shorter the conduction path is and the larger the conduction area is, the lower the thermal conductivity is.

As shown inFIG. 29, in this embodiment, the light board3includes at least one LED chip set31having LED chips311.

As shown inFIG. 29, in this embodiment, the light board3is divided into three areas comprising an inner ring, a middle ring and an outer ring. All the LED chip sets31are located in the three areas. In one example, the inner ring, the middle ring and the outer ring are separately mounted by different amount of LED chip sets31. In another aspect, the light board3includes three LED chip set31. The three LED chip sets31are respectively located in the inner ring, the middle ring and the outer ring. Each of the LED chip sets31separately in the inner ring, the middle ring and the outer ring has at least one LED chip311.

Four hypothetical circle lines are defined on the light board3as shown inFIG. 29. The outer ring is defined by the area between the outermost two circle lines of the four, the inner ring is defined by the area between the innermost two circle lines of the four, and the middle ring is located between the two areas mentioned above. In another embodiment, the light board3is separated into two rings (areas), and the chip sets31are divided to be mounted on the two rings.

As shown inFIG. 29, several LED chips311in a circle or approximately in a circle compose an LED chip set. There are several LED chip sets31on the light board3. In a single LED chip set31, a center distance between two adjacent LED chips311is L2. A center distance between any LED chip311of any LED chip set31and the nearest LED chip311of an adjacent LED chip set31is L3. The ratio of L2to L3is 1:0.8˜2, preferably, L2:L3is 1:1˜1.5. This makes distribution of the LED chips311so even to accomplish an object of even light output.

FIG. 40is a schematic view of the combination of the fins11and the LED chips311of one embodiment. As shown inFIGS. 29 and 40, in this embodiment, when at least one fin11is projected onto the plane on which the LED chip sets31are located along the axial direction of the LED lamp, a projection of the fin11at least touches at least one LED chip311of the LED chip set31. In detail, when at least one fin11is projected onto a plane on which the LED chip set31is located along the axial direction of the LED lamp, a projection of the fin11at least touches at least one LED chip311of the LED chip set31in the inner ring, the middle ring or the outer ring. As shown inFIG. 40, the projection of the fin11touches an LED chip311. As indicated by the arrow in the figure, it is a heat dissipating path of the LED chip311and the fin11. As shown inFIG. 41, the projection of the fin41does not touch the LED chip311in the figure. As indicated by the arrow in the figure, it is a heat dissipating path of the LED chip311and the fin11. It can be seen that the heat dissipating path of the latter is longer than the former's. As a result, by means of a projection of a fin at least touching at least one LED chip311of the LED chip set31in the inner ring, the middle ring or the outer ring, a heat dissipating path of the LED chip311can be shortened. This can reduce thermal resistance to be advantageous to thermal conduction. Preferably, a fin11is projected onto a plane on which the LED chip set31is located along the axial direction of the LED lamp, a projection of any fin11(the first fin111or the second fin112) at least touches at least one LED chip311of the LED chip set31.

In this embodiment, the LED chip sets31in outer rings corresponding to the fins11are greater than the LED chip sets31in inner rings in number. Here the term “corresponding to” means projection relationship in the axial direction of the LED lamp, for example, when the LED chip sets31in outer rings are projected onto the fins11in the axial direction of the LED lamp, the fins11to which the LED chips31in outer rings correspond are located on a relatively outer portion of the heat sink1. Here the LED chip sets31in outer rings have more LED chips311in number, so they need more fins11(area) to implement heat dissipation.

As shown inFIGS. 1 and 29, the light board3has an inner border3002and an outer border3003. Both the inner border3002and the outer border3003separately upward extend along the axial direction of the LED lamp to form a region. An area of part of the fins11inside the region is greater than an area of part of the fins11outside the region. As a result, the most of the fins11can correspond to the light board3(a shorter heat dissipating path) to enhance heat dissipating efficiency of the fins11and increase effective area of heat conduction of the fins11to the LED chips311.

As shown inFIGS. 3, 5 and 29, a reflecting region3001is disposed in a region between the inner ring and an outer edge of the light board3to reflect the upward light to the light output surface43. This can reduce loss of light in an opposite direction of light output in the axial direction of the LED lamp to increase overall intensity of light output.

As shown inFIGS. 4 and 29, the light board3is formed with a third aperture32separately communicating with the first heat dissipating channel7aand the second heat dissipating channel7b. For example, the third aperture32communicates with spaces between the fins11and the chamber of the lamp shell2to form air convection paths between the spaces between the fins11and between the chamber of the lamp shell2and the outside of the Led lamp. The third aperture32is located inside the inner ring of the LED lamp. Thus, it would not occupy the space of the reflecting region3001to affect reflective efficiency. In detail, the third aperture32is located at a central region of the light board3and both the first air inlet2201and the second air inlet1301make air intake through the same aperture (the third aperture32). In one example, after convection air passes through the third aperture32, and then enters the first air inlet2201and the second air inlet1301. The third aperture32is located at a central region of the light board3, so both the first air inlet2201and the second air inlet1301can commonly use the same air intake. Thus, this can prevent occupying an excessive region of the light board3and prevent the usable regional area of the light board3for disposing the LED chips311from decreasing due to multiple air intakes. On the other hand, the sleeve21corresponds to the third aperture32, so convection air may have an effect of thermal isolation to prevent temperatures inside and outside the sleeve21from mutually affecting each other when air enters. In other embodiments, if both the first air inlet2201and the second air inlet1301are located at different positions, then the third aperture32may be multiple in number to correspond to both the first air inlet2201and the second air inlet1301. In detail, as shown inFIG. 42, the third aperture32may be located at a middle portion or outer portion or between the LED chips311to correspond to both the first air inlet2201and the second air inlet1301stopped

As shown inFIG. 29, in an embodiment, in the inner ring, both adjacent two of the LED chips311and the axis of the LED lamp form a center angle A; in the middle ring, both adjacent two of the LED chips311and the axis of the LED lamp form a center angle B. The center angle B is less than the center angle A in degree. In the outer ring, both adjacent two of the LED chips311and the axis of the LED lamp form a center angle C, and the center angle C is less than the center angle B in degree. For example, the LED chips311in the outer ring are more than those in the middle ring in number. Thus, a distance between adjacent two of the LED chips311in the outer ring is not much greater than a distance between adjacent two of the LED chips311in the middle ring, even, the two distances may be similar or identical. As a result, both distribution of the LED chips311and light output will be very even. In one example, the LED chip sets31are multiple in number and are annularly mounted on the light board3. A center angle formed by adjacent two of the LED chips311in an inner portion and the axis of the LED lamp is greater than a center angle formed by adjacent two of the LED chips311in an outer portion and the axis of the LED lamp. That is, The LED chips311of outer LED chip sets31are greater than the LED chips311of inner LED chip sets31in number such that a distance between adjacent two of the LED chips311of outer LED chip sets31is less than a distance between adjacent two of the LED chips311of inner LED chip sets31. As a result, both distribution of the LED chips311and light output will be very even.

As shown inFIG. 40, in one embodiment of the present invention, the light board3is provided with an insulative layer34with high reflectivity. The insulative layer34may adopt thermal grease. The insulative layer34is smeared on the light board3to an edge thereof. A distance between the LED chips311at the outermost position and an edge of the light board3is greater than 4 mm. Preferably, a distance between the LED chips311at the outermost position and an edge of the light board3is greater than 6.5 mm but less than 35 mm. In addition, a creepage distance between the outermost LED chips311and the heat sink1can be guaranteed to prevent arc occurring between the LED chips311and the heat sink. In addition, the insulative layer34may also have an effect of thermal isolation to prevent overheating and deformation of the lamp cover4.

FIG. 43is a schematic view of the light board3in this embodiment. As shown inFIG. 43, in this embodiment, the LED chip sets31are at least two in number. The at least two LED chip sets31are annularly arranged on the light board3in order. Each LED chip set31includes at least one LED chip311. Each LED chip311of one of the LED chip sets31on the light board3is radially interlacedly arranged with any one LED chip311of adjacent one of the LED chip sets31on the light board3. That is, the LED chips311of different LED chip sets31are located in different directions in a radial direction of the LED lamp. In one example, if any line starting with the axis of the LED lamp and extending toward a radial direction of the LED lamp cuts two or more of the LED chips311, then it will cut different positions of these two or more LED chips311and will not cut the same positions of these two or more LED chips311. As a result, if there is convection on the light board3and air radially flows on the light board3, the contact between air and the LED chips311will be more sufficient and a better effect of heat dissipation will be obtained because of the airflow paths. In addition, in the aspect of lighting effect, such distribution of the LED chips311is more advantageous to uniformity of light output.

In this embodiment, an open region312is formed between adjacent two of the same LED chip set31to allow air to flow between the LED chips311to bring out heat generated from the working LED chips311. The open region312between any two adjacent LED chips311of one of adjacent two of the chip sets31on the light board3interlaces to and communicates with the open region312between any two adjacent LED chips311of another one of the chip sets31on the light board3in a radial direction of the LED board3. As a result, if there is convection on the light board3and air radially flows on the light board3, the contact between air and the LED chips311will be more sufficient and a better effect of heat dissipation will be obtained because of the airflow paths. If both the open region312between any two adjacent LED chips311of one of adjacent two of the chip sets31on the light board3and the open region312between any two adjacent LED chips311of another one of the chip sets31on the light board3of the LED board3are in the same radial direction, then air will flow along radial directions of the light board3. The contact between air and the LED chips311will decrease to be disadvantageous to heat dissipation of the LED chips311because of the airflow paths.

For example, three LED chip sets31are annularly disposed along a radial direction of the light board3in order, any open regions312of the three LED chips31are not in the same direction in a radial direction. Thus, convection paths on the light board3can be optimized to increase efficiency of the heat dissipation.

In some applications, when LEDs are emitting, a light distribution region will be formed under the LED lamp. This means distribution of intensity of light source. The design of the LED lamp aims for concentrating the light distribution region to a specific zone to increase local intensity.

FIGS. 44a˜44fare schematic views of some embodiments of the light board3. As shown inFIGS. 44aand 44b, the light board3includes a first region35for installing the LED chip set31, a second region36inside the first region35and a third region37outside the first region35. The first region35restricts a range of installing the LED ship set31. The first, second and third regions35,36,37may be provided with insulative layers (not shown) with reflectivity on the surface.

As shown inFIGS. 44aand 44b, the third region37is located away from the first region35in a radial direction of the LED board3. The distance between the third region37and the first region35is gradually increase in the axial direction. Thus, a surface of the third region37is formed with an outer reflecting region371outside the LED chip set31so as to guide at least part of light from the LED chip set31to the light output surface. This can concentrate light to a specific area.

As shown inFIG. 44b, the second region36is located close to the center in a radial direction of the LED board3. The distance between the second region36and the first region35is gradually increase in the axial direction. Thus, a surface of the second region36is formed with an inner reflecting region361inside the LED chip set31so as to guide at least part of light from the LED chip set31to the light output surface43. This can concentrate light to a specific area.

In the above embodiments, both the inner reflecting region361and the outer reflecting region371of the light board3and both the inner reflecting surface4301and the outer reflecting surface4302of the lamp cover4may be arbitrarily combined and arranged to implement various optical effects. For example, only both the inner reflecting region361and the inner reflecting surface4301are disposed, only both the outer reflecting surface4302and the outer reflecting region371are disposed, or both either of the inner reflecting region361and the inner reflecting surface4301and either of the outer reflecting surface4302and the outer reflecting region371are disposed.

As shown inFIGS. 44aand 44b, the inner reflecting region361or the outer reflecting region371is a flat plane and inclines to the first region35to form an angle or is a curved surface.

In some embodiments, a direction of light output of the LED chips311can be adjusted by changing a mounting direction thereof. In detail, adjusting a structure of the light board3can make the LED chips311have various effects of light output. For example, as shown inFIG. 44c, in some embodiments, the light board3includes a first region35for installing the LED chip set31, a second region36inside the first region35and a third region37outside the first region35. There are several LED chip sets31on the light board3. The LED chip sets31are annularly arranged on the light board3. In this embodiment, at least one LED chip set31is located in the third region37which inclines to the first region36to form an angle. At least one LED chip set31located in the third region37can change an angle of light output to present a different effect of light output. This can change distribution of intensity.

Identically, at least one LED chip set31is located in the second region36which inclines to the first region36to form an angle. At least one LED chip set31located in the second region36can change an angle of light output to present a different effect of light output. This can change distribution of intensity.

The light board3shown inFIG. 44cas an example, the LED chip sets31are three in number and the outermost LED chip set31is located in the third region37. The LED chip set31in a middle position among the three LED ship sets31is located in the first region35, and the LED chip set in an innermost position is located in the second region36.

In the above embodiment, both the second and third regions36,37are used for installing the LED chips311. Each LED chip311corresponds to one second region36or third region37. Both the second and third regions36,37may also be an integrated region on which the LED chips311of the same LED chip set31are mounted.

As shown inFIG. 44d, in some embodiments, to enhance lighting efficiency of the LED chips311, surfaces of the LED chips311are separately disposed with silicone layers313. Each LED chip311is disposed with an individually silicone layer313. An out surface of the silicone layer313is a convex surface to form a lens which is capable of focusing light from the LED chips311. This makes an effect of light output better and is advantageous to increase of illuminance. In addition, the silicone layer313can also improve efficiency of thermal radiation (increase its radiating area) to be advantageous to heat dissipation of the LED chips311.

As shown inFIG. 44e, in some embodiments, the light source includes the light board3, the LED chips311and the silicone layers313. The silicone layer313includes a first silicone layer3131on a surface of the light board3and a second silicone layer3132on a surface of the LED chip311. The first silicone layer3131cloaks and isolates the light board3to make the light board insulated. The second silicone layer3132has a convex surface to form a lens which focuses light from the LED chips311. This makes an effect of light output better and is advantageous to increase of illuminance. Also, considering the manufacturing process of the first silicone layer3131and the second silicone layer3132, the thickness of the first silicone layer3131is approximately the same as that of the LED chip311, such that the first silicone layer3131will not cause any effect in the emitting of the LED chip311.

Both the first silicone layer3131and the second silicone layer3132are integratedly formed to be the silicone layer313for resisting dust. At this time, the lamp cover4may be omitted to increase lighting efficiency (unavoidably, the lamp cover4obstructs part of light to cause light loss). As shown inFIG. 44f, in some embodiments, silicone in LED chip packing may be omitted. The silicone layer313is directly disposed outside the fluorescent powder314. That is, the fluorescent powder314is disposed outside the chip3111and the silicone layer313is disposed outside the fluorescent powder314. In addition, the silicone layer313can also improve efficiency of thermal radiation (increase its radiating area) to be advantageous to heat dissipation of the LED chips311.

FIGS. 45a˜45gare top views of some embodiments of the light board3mwhich show different distribution of the LED chips311. InFIG. 45a, the LED chips311of a single LED chip set31are directly mounted on the bae board33at regular intervals. That is, a distance between any adjacent two of the LED chips311is identical to make the whole light board3capable of even lighting. InFIGS. 45b, and 45c, the LED chips311of a single LED chip set31are arranged in array. The array may be a matrix as shown inFIG. 45bor a triangular array as shown inFIG. 45c. Of course, the LED chips31may be arranged in a concentric annular shape as abovementioned. Such an array can concentrate the LED chips311to a local area on the base board33to generate a concentrated lighting effect with even light output in the local area.

FIG. 45dshows an embodiment of multiple LED chip sets31independently forming respective arrays, in which each LED chip set31contains LED chips311. A triangular dotted box encompasses an LED chip set31. A distance is kept between two adjacent arrays, which is greater than a distance between adjacent two of the LED chips311. Thus, an airflow channel is formed between two adjacent arrays to promote air convection on the light board3.

As shown inFIG. 45e, in some embodiments, each LED chip311of the LED chip set31is of a rectangular shape with a long side and a short side. As shown inFIG. 45e, the LED chips311are arranged along a circle and the long sides are arranged along radial directions of the LED light board3to make the LED chips311present a radial arrangement. Thus, more LED chips311can be arranged on this circle and concentrated in a small area. Meanwhile, the long sides provide longer convection paths in radial directions to increase thermal exchange between airflow and the LED chips311. In addition, the LED chips311are arranged along a circle and the short sides are arranged along radial directions of the LED light board3to make the LED chips311distributed on a large area and to shorten a distance between two adjacent LED chips311. Such an arrangement makes the LED chips311look like a lighting ring. The abovementioned two arrangements may be jointly or alternatively implemented.

FIGS. 45f˜45gare local schematic views of some diverse embodiments of the light board3. As shown inFIGS. 45fand 45g, in some embodiments, the base board33of the light board3is provided with one or more reflecting cups334. Opening s of the reflecting cups334are toward an opposite direction of the base board33. The inside bottom of each reflecting cup334is disposed with an LED chip311. An inner side of the reflecting cup334is formed with a material with high reflectivity. Available solutions are to coat or electroplate the inner side of the reflecting cup334with a coating with high reflectivity or directly make the reflecting cup334with a material with high reflectivity and polish the inner side. The inner side of the reflecting cup334can reflect lateral light output of the LED chip311to make the light from the LED chip311focused a direction to which the LED chip311is directed.FIG. 45gis a variation ofFIG. 45f. There are multiple LED chips311mounted on the inside bottom of each reflecting cup334. In one example, each reflecting cup334is disposed with at least one LED chip311.

FIGS. 46a˜46care perspective views of the power source5of one embodiment at different viewpoints.FIG. 46dis a main view of the power source5of one embodiment. The power source5is electrically connected to the LED chips311to power the LED chips311. As shown inFIGS. 46a˜46c, the power source5includes a power board51and a plurality of electronic components mounted thereon.

As shown inFIG. 46c, a transformer54in the electronic components includes a core541and coils542. The core541has a room in which the coils542is received. The room has an opening in the axial direction of the LED lamp so as to make heat generated from the coils542and the core541move upward. Also, the heat dissipating direction of the transformer54is consistent with the convection path of the first heat dissipating channel7a(as mentioned in the description ofFIG. 4) for being advantageous to heat dissipation.

As shown inFIGS. 46band 46c, the room is provided with two openings at two ends in the axial direction of the LED lamp to increase heat dissipating effect to the coils542. In addition, after the coils542are installed in the room of the core541, a gap is kept between the coils542and the room to allow air to flow. This can further increase heat dissipating effect to the coils542.

As shown inFIG. 46b, the transformer54has a first side5401and a second side5402, both of which are perpendicular to the power board. The first side5401is perpendicular to the axial direction of the lamp. The first side5401is less than the second side5402in area. Thus, such an arrangement of the small side can reduce resistance to convection of the first heat dissipating channel7a.

As shown inFIG. 46c, the electronic components include at least one inductor755including an annular core551. A coil is wound around the annular core551(not shown). An axis of the annular core551is parallel to the axis of the LED lamp to make the coil have larger area to be in contact with convection air. This can further increase heat dissipating effect to the inductor55. In addition, a shape of the annular core551corresponds to the convection path of the first heat dissipating channel7a. Thus, convection air can pass through the inside of the annular core551to further increase heat dissipating effect to the inductor55.

As shown inFIGS. 46aand 46b, heat-generating elements in the electronic components include integrated circuits (ICs)56, diodes, transistors, the transformer54, the inductor55and resistors. These heat-generating elements are separately mounted on the power board51to distribute heat-generating sources and prevent local high temperature. In addition, the heat-generating elements may be mounted on different surfaces of the power board51to perform heat dissipation. At this time, the heat-generating elements are in contact with corresponding heat dissipating elements.

As shown inFIGS. 46aand 46b, at least one IC56is arranged to be mounted on different surface as other heat-generating elements are arranged of the power board51. As a result, the heat-generating sources can be separated to avoid local high temperature and influence to the IC56from the other heat-generating elements.

As shown inFIGS. 46aand 46b, in a direction perpendicular to the power board51(i.e. projection relationship in a direction perpendicular to the power board51), the IC56does not overlap any heat-generating elements to avoid heat accumulation.

As shown inFIG. 22, the power board51is parallel to the axis of the LED lamp. Thus, in the axial direction of the LED lamp, the power board51is divided into an upper portion and a lower portion. Arranging spaces of both the upper portion and the lower portion are identical or approximately identical to form better layout of the electronic components. Besides, if the power board51inclines toward the axis of the LED lamp, then air flow may be obstructed and it is disadvantageous to heat dissipation of the power source5.

As shown inFIGS. 1 and 22, the power board51divides the lamp shell2into a first portion201and a second portion202. Area of the venting hole222corresponding to the first portion201is greater than area of the venting hole222corresponding to the second portion202. Thus, when implementing layout of electronic components, most or all of electronic components or some thereof which generate a large amount of heat such as inductors, resistors, transformers, rectifiers or transistors may be disposed in the first portion201.

As shown inFIG. 22, the power board51divides an inner chamber of the lamp shell2into a first portion201and a second portion202. The first portion201is greater than the second portion202in volume. When implementing layout of electronic components, most or all of electronic components or some thereof which generate a large amount of heat such as inductors, resistors, transformers, rectifiers or transistors may be disposed in the first portion201.

Please simultaneously refer toFIGS. 22 and 29, further, area of first air inlet2201corresponding to the first portion201is greater than area of the second air inlet2202corresponding to the second portion202. Thus, more air can flow into the first portion201to perform heat dissipation to the electronic components. Here, the specific description of the air inlet is that the first air inlet2201is divided into two portions by the power board51, one of the two portions corresponds to the first portion201and the other one of the two portions corresponds to the second portion202so as to make more air flow into the first air inlet2201and enter the first portion201.

As shown inFIG. 22, the electronic components501include heat-generating elements501. At least one of the heat-generating elements501is adjacent to the lamp head23through which heat is dissipated without occupying resource of heat dissipation of the first heat dissipating channel7a. The at least one heat-generating element501abovementioned is an inductor, a resistor, a rectifier or a control circuit.

As shown inFIG. 22, heat of the at least one heat-generating element is transferred to the lamp head23through thermal conduction or radiation and dissipated to air through the lamp head23.

As shown inFIG. 22, the at least one heat-generating element501is in thermal contact with the lamp head23. In detail, the at least one heat-generating element501is located in the lamp head23. The heat-generating element501is in contact with the lamp head23through a thermal conductor53and the heat-generating element501is fastened to the lamp head23through the thermal conductor53. Therefore, the thermal conductor not only performs an effect of heat transfer but also fixes the heat-generating element501to avoid loosening of the heat-generating element501. The phrase “the heat-generating element501is located in the lamp head23” means both the lamp head23and the heat-generating element501have an overlapping area in a projection perpendicular to the axis of the LED lamp.

As shown inFIG. 22, the thermal conductor53is disposed in the lamp head23through filling to implement connection between the lamp head23and the heat-generating element501. The thermal conductor53only cloaks an end portion of the power source5and is higher than the venting222in position to prevent overweight resulting from the thermal conductor53. Additionally, the thermal conductor53adopts an insulative material to guarantee safety and prevent the electronic components and metal portion231of the lamp head23from being in contact. In other embodiments, the thermal conductor53may also be a wire connecting the power source5to the lamp head23(not shown).

As shown inFIG. 22, the lamp head23includes the metal portion231, which is in thermal contact with the thermal conductor53. That is, at least part of an inner side of the metal portion231constitutes a wall of the inner chamber of the lamp shell2to make the thermal conductor directly connect with the metal portion231and perform heat dissipation by the metal portion231. Part of the metal portion231would perform heat dissipation through air, and another part of the metal portion would perform heat dissipation through a lamp socket connecting to the metal portion231.

As shown inFIGS. 2 and 46a, in this embodiment, at least one of the electronic components of the power source5, which is the most adjacent to the first air inlet2201of the first heat dissipating channel7ais a heat intolerance component, such as a capacitor, especially for an electrolytic capacitor. This arrangement can avoid overheating of the heat intolerance component to affect its performance.

In addition, to reduce influence of an electrolytic capacitor502suffering heat from the heat-generating elements, a surface of the electrolytic capacitor can be provided with an anti-radiation layer or a thermo-isolation layer (not shown). The thermos-isolation layer may adopt existing plastic material, and the anti-radiation layer may adopt existing paint, silver plate layer, aluminum foil or other anti-radiation materials.

As shown inFIG. 46a, in this embodiment, at least part of at least one of the electrolytic capacitors502is not located within the power board51, i.e. at least part of the electrolytic capacitor exceeds the power board51in the axial direction of the LED lamp. Under a condition of the same number of the electronic components, length and material cost of the power board51. In addition, this can make the electrolytic capacitor further adjacent to the first air inlet2201to ensure the electrolytic capacitor to be located in a relatively low temperature area.

As shown inFIG. 22, a position of at least one of the heat-generating elements501in the axial direction of the LED lamp is higher than a position of the venting hole222. Most heat of the heat-generating element501higher than the venting hole222is dissipated through the lamp head23or other paths. Thus, most heat therefrom is not dissipated through the venting hole222, and convection speed of the first heat dissipating channel7awould not be affected. The heat-generating element is an IC, a transistor, a transformer, an inductor, a rectifier or a resistor.

As shown inFIG. 22, the power board51is divided into an upper part and a lower part in the axial direction of the LED lamp. Heat-generating elements are arranged in both the upper part and the lower part. At least one of the heat-generating elements in the upper part is located above the venting hole222to lower the temperature of the upper part near the venting hole222. This can increase an air temperature difference between two venting holes222in the upper part and the lower part to enhance convection.

As shown inFIGS. 2, 3 and 46a, when the power board51is assembled in the lamp shell2, it has a first portion in the lamp neck22and a second portion in the sleeve21. The second portion more adjacent to the first air inlet2201of the first heat dissipating channel7athan the first portion. Because of such an arrangement, convention air will reach the second portion first. That is, the second portion is better than the first portion in an effect of heat dissipation. Thus, at least part of heat intolerance elements (e.g. electrolytic capacitors or other elements which is sensitive to high temperature) should be disposed in the second portion. Preferably, all electrolytic capacitors are disposed in the second portion. The power board51of the second portion is greater than the first portion in area, so the power board51of the second portion has more space for accommodating electronic components to be advantageous to more heat intolerance elements being disposed in the second portion. In this embodiment, heat intolerance elements/thermo-sensitive elements may be separately mounted on two opposite sides of the second portion. In other embodiments, hotter electronic components may be disposed in the second portion (e.g. transformers, inductors, resistors, ICs or transistors) for better heat dissipation.

FIG. 51is a schematic of an embodiment of the power source5. As shown inFIG. 51, the power board51has a thermo-isolation plate513. The power board51is divided into two zones by the thermos-isolation plate513. One of the two zones is used to be mounted by heat-generating elements (e.g. transformers, inductors, resistors, etc.), and the other zone is used to be mounted by heat intolerance/thermos-sensitive elements (e.g. electrolytic capacitors). That is, the thermos-isolation plate513partitions heat-generating elements and heat intolerance/thermo-sensitive elements to prevent the latter from being affected by thermal radiation from the former. In other embodiments, heat-generating elements are disposed in both zones. That is, the thermo-isolation plate513partitions two heat-generating elements to prevent mutual thermal radiation which causes thermal accumulation. In another aspect, temperature is an important factor of thermal radiation, so avoiding mutual thermal radiation between heat-generating elements can rise a temperature difference between a heat-generating element and air therearound so as to improve efficiency of thermal radiation. Preferably, the thermo-isolation plate513is arranged along the axis of the LED lamp or the convection direction of the first heat dissipating channel7ato make heat in two sides would not make convection in a width direction of the power board51to prevent heat gathering when convection is processing. The thermo-isolation plate is extendedly arranged along the convection direction of the first heat dissipating channel7a. That is, the thermo-isolation plate513is extendedly arranged along the axis of the LED lamp, so obstruction to convection air would not occur. In other embodiments, the thermo-isolation plate513may be slant to form a guiding effect to air.

Furthermore, the thermo-isolation plate513may be a circuit board, so the thermo-isolation plate513may be disposed with electronic components to increase area for mounting electronic components.

The function of the thermo-isolation plate513may be replaced with electronic components. As shown inFIG. 46d, there are three electronic components503,504,505on the power board51. At least parts of projections of the three electronic components503,504,505in a radial direction of the LED lamp (or a width direction of the power board51) overlap with another one. The one504of the three electronic components503,504,505is located between the other two503,505to avoid mutual thermal radiation between the two electronic components503,505. This is advantageous to forming a greater temperature difference between the heat-generating elements and air therearound and radiating heat from the heat-generating elements to air. The abovementioned two electronic components503,505are respective a heat-generating element (such as a transformer, a resistor or a transistor) and a heat intolerance elements/thermo-sensitive element (such as an electrolytic capacitor), so at least part of heat from the heat-generating elements (one of the electronic components503and505) would be thermally radiated to the in-between electronic component504to reduce thermally radiative influence to the heat intolerance elements/thermo-sensitive element from the heat-generating elements.

In the other embodiment of the present invention, the three electronic components503,504,505on the power board51positioned as mentioned above, both electronic components503,505are a heat-generating element (such as a transformer, a resistor or a transistor), so at least part of heat generated from the heat-generating elements (electronic components503and505) would be thermally radiated to the in-between electronic component504. Under these circumstances the electronic component504plays a role for preventing the heat generated from the two heat-generating elements being superposed to effect the working quality of the LED lamp due to overheated temperature occurred in the power board51area.

Preferably, the in-between electronic component504adopts non-heating or heat-resistant electronic component such as a temperature sensor or a capacitor.

As shown inFIG. 46d, in other embodiments, there are three electronic components506,507,508on the power board51. At least parts of projections of the three electronic components506,507,508in the axial direction of the LED lamp (or in a width direction of the power board51, i.e. along a convection direction of the first heat dissipating channel7a) overlap with another one. The one507of the three electronic components506,507,508is located between the other two506,508to avoid mutual thermal radiation between the two electronic components506,508. This is advantageous to forming a greater temperature difference between the heat-generating elements and air therearound and radiating heat from the heat-generating elements to air. The abovementioned two electronic components506,508are heat-generating elements (such as transformers, resistors, inductors or transistors), so at least part of heat from the heat-generating elements506,508would be thermally radiated to the in-between electronic component507to reduce thermally radiative influence to the heat intolerance elements/thermo-sensitive element from the heat-generating elements and to avoid heat accumulation. In this embodiment, by such an arrangement of the electronic component507, it will obstruct upward convection air flow. For example, after heat from the lower electronic component506is brought out by convection air, the convection air must bypass the in-between electronic component507to avoid direct contact with the upper electronic component508. In this embodiment, the in-between electronic components507is a non-heat-generating element (such as a capacitor). In other embodiments, the other two electronic components506,508are a heat-generating element (such as transformers, resistors or inductors) and a heat intolerance element (such as a capacitor).

FIG. 52is a schematic view of an embodiment of the power source5. In some embodiments, to improve radiative efficiency of the heat-generating elements of the power source5, a radiating layer509may be provided on surfaces of the heat-generating elements. Heat from working heat-generating elements can be thermally conducted to the radiating layer509, and then the radiating layer509radiates the heat to surrounding air to bring out hot air when convection is processing in the first heat dissipating channel7a. The radiating layer509is greater than the heat-generating elements in radiative efficiency so as to significantly improve efficiency of heat dissipation of the heat-generating elements with the radiating layer509. In this embodiment, the radiating layer509may adopt existing black glue to increase an effect of radiating to air. The black glue covers a surface of the power source5and may be in thermal contact with the lamp head23. That is, part of heat from the heat-generating elements of the power source5is radiated to surrounding air and another part thereof is thermally conducted to the lamp head23through the black glue (not shown). The lamp head23is metal, so the heat can be further dissipated to the outside through the lamp head23. In this embodiment, the black glue is of a thin layer attached on a surface of a heat-generating element without obstructing convection in the first heat dissipating channel7a. The black glue with light weight would not add substantial weight. In other embodiments, the black glue may be selectively disposed, for example, the black glue is disposed on heat-generating elements with high heat such as transformers, inductors or transistors.

In addition, in the above embodiment, to further increase radiative efficiency of the radiating layer509, the radiating layer509can be configured to be a rough surface to increase surface area.

FIG. 47is a schematic view of an embodiment of the power source5, which can be applied to the power source5of the LED lamp shown inFIG. 4. As shown inFIG. 47, in some embodiments, the power board51is divided into a first mounting zone511and a second mounting zone512by an axis X. The axis X is between the first mounting zone511and the second mounting zone512as a border. Total weight of the electronic components on the second mounting zone512is greater than total weight of the electronic components on the first mounting zone51. The first mounting zone511is provided with a counterweight52to balance the two zones511,512of the power board51in weight. This can prevent unbalanced weight of the two zones511,512of the power board51and prevent the hung LED lamp from tilting because of unbalanced weight.

FIG. 48is a main view of the counterweight52ofFIG. 47.FIG. 49is a side view ofFIG. 48. As shown inFIGS. 48 and 49, in some embodiments, the counterweight52is a heat dissipating element with heat dissipating function and is disposed on the power board51. In some embodiments, the heat dissipating assembly has fins521for increasing heat dissipating area. The counterweight52is made of metal with high thermo-conductivity such as aluminum or copper. In this embodiment, the fins521are extendedly arranged along the axial direction of the LED lamp. A channel is formed between two adjacent fins521as an air passage. Such an arrangement can increase heat dissipating area of the counterweight52. In one embodiment, the counterweight52includes a long side and a short side. The channels are parallel with the long side and the long side is configured to be parallel with the axis of the LED lamp or substantially parallel with the direction of airflow to make the air flow smoothly.

As shown inFIG. 47, the electronic components include heat-generating elements which generate heat when working. At least one heat-generating element is adjacent to a heat dissipating assembly to dissipate part of heat through the heat dissipating assembly. Preferably, transformers, inductors, resistors, diodes, transistors or ICs of the heat-generating elements are adjacent to the heat dissipating assembly. More preferably, transformers, inductors, resistors, diodes, transistors or ICs of the heat-generating elements are in direct contact with the heat dissipating assembly.

In one embodiment of the present invention, two opposite sides of the circuit board all comprise the counterweight52, such that the heat dissipating efficiency of the circuit board51and the weight balance between two sides of the circuit board51can be improved simultaneously.

As shown inFIG. 47, in some embodiments, the power board51is divided into a first mounting zone511and a second mounting zone512by an axis X. The axis X is between the first mounting zone511and the second mounting zone512as a border. The second mounting zone512is greater than the first mounting zone511in number of electronic components to make airflow of the first mounting zone511smooth and to reduce obstruction of the electronic components. In this embodiment, both the first mounting zone511and the second mounting zone512have heat-generating elements to distribute heat sources.

As shown inFIGS. 4, 47 and 50, in some embodiments, the first heat dissipating channel7aincludes an inner channel7a1and an outer channel7a2. The outer channel7a2is formed between the electronic components on an edge of the power board51and an inner wall of the inner chamber of the lamp shell2. The inner channel7a1is formed in gaps between the electronic components. This arrangement can enhance an effect of heat dissipation of the power source5. In detail, the power board51inFIG. 47is divided into two portions (a left portion and a right portion, not necessarily symmetrical), namely, a first portion and a second portion. Both the first portion and the second portion have electronic components. The outer channel7a2is formed between the electronic components on both the first portion and the second portion and the inner wall of the lamp shell2. The inner channel7a1is formed between the electronic components separately on the first portion and the second portion. In this embodiment, a transformer54of the electronic components includes a core541and coils542. The core541has a chamber in which the coils542are disposed. An opening is formed at a side of the chamber in a radial direction to expose the coils542. The opening corresponds to the inner channel7a1or the outer channel7a2to make heat from the coils542is rapidly ejected through convection in the inner channel7a1or the outer channel7a2. Preferably, two openings are separately formed at two sides of the chamber in a radial direction. One of the two openings corresponds to the inner channel7a1and the other one thereof corresponds to the outer channel7a2to further enhance heat dissipation of the transformer.

FIGS. 53a˜53care schematic view of various embodiments of the power source board51. As shown inFIG. 53a, the power board51includes multiple sub-boards512which electrically connect to each other. As shown inFIG. 53a, the sub-boards512are connected by one or more wires513. When multiple wires are used, they can be combined to be a flexible flat cable. Relative positions of the sub-boards512can be changed by bending the wire513, for example, two sub-boards512are kept parallel at an interval and are separately mounted by different groups of electronic components. As shown inFIG. 53b, the sub-boards512are connected by one or more electric connectors514by which the sub-boards512can be firmly combined in a parallel or coplanar manner. For example, two sub-boards512are kept parallel at an interval and are separately mounted by different groups of electronic components. As shown inFIG. 53c, the power board51includes a first zone51aand a second zone51b. The second zone is greater than the first zone in width for accommodating more heat intolerance electronic components. The second zone51bis adjacent to an intake172of the base17and the first zone51ais adjacent to the venting hole222of the lamp neck22.

FIG. 54is a cross-sectional view of the LED lamp of one embodiment. As shown inFIG. 54, the power board51divides the heat dissipating channel (here it means the first heat dissipating channel7a) into a first channel S1and a second channel S2along the axis of the heat dissipating channel. The power board51includes a first side and a second side. The first side corresponds to the first channel S1and the second side corresponds to the second channel S2.

When an electronic component has large volume, the heat dissipating channel it is located has to need correspondingly large volume. As a result, a sufficient channel space can be kept after the volume of the heat dissipating channel minus the total volume of the electronic component. Thus, when the first channel S1is less than the second channel S2in volume, volume of the electronic components on the first side (a total volume of all electronic components on the first side) must be less than volume of the electronic components on the second side (a total volume of all electronic components on the second side). The ratio of volume of the first heat dissipating channel S1to the second channel S2is defined as R1, and R1is between 0.3 and 0.5. The ratio of volume of the electronic components on the first side to volume of the electronic components on the second side is defined as R2, and R2is between 0.05 and 0.2. In the aspect of the ratio relationship, the ratio R1of volume of the first channel S1to volume of the second channel must be less than the ratio R2of volume of the electronic components on the first side to volume of the electronic components on the second side. If weight of the electronic components on the first side is less than weight of the electronic components on the second side, then a counterweight (not shown) may be added on the first side to balance weight on two sides.

FIG. 55is a cross-sectional view of the LED lamp of one embodiment. As shown inFIG. 55, if further divide upper and lower relationship, on the same side (either the first side or the second side), heat dissipating channel must be considered (here the heat dissipating channel means the first heat dissipating channel7a), i.e. relationship of air flow zones (not cover electronic components). The second side as an example, a first quadrant Q1, a second quadrant Q2, a third quadrant Q3and a fourth quadrant Q4are defined on the second side by an X-axis and a Y-axis. The first quadrant Q1, the second quadrant Q2, the third quadrant Q3and the fourth quadrant Q4communicate with each other. Both the first quadrant Q1and the second quadrant Q2correspond to the lamp shell2, and both the third quadrant Q3and the fourth quadrant Q4correspond to the heat sink1. The first quadrant Q1abuts against the third quadrant Q3, and the second quadrant Q2abuts against the fourth quadrant Q4. The X-axis is located on an upper edge of the heat sink1, and the Y-axis is the central axis shown in the figure.

As shown inFIG. 55, an ideal manner is to place all electronic components on a single side (one side of Y-axis), for example, gathering in both the second quadrant Q2and the fourth quadrant Q4, and lower electronic components are less than upper electronic components in number and high heat or heat intolerance electronic components (such as transformers or electrolytic capacitors) are located in the lower portion. As shown, volume of the electronic components in the second quadrant Q2is less than volume of the electronic components in the first quadrant Q1to make an air flow zone (not cover electronic components) shown in the second quadrant Q2is greater than the first quadrant Q1to keep a zone allowing air to rapidly flow. Thus, the second side as an example, the ratio of volume of the first channel S1in the second quadrant Q2to volume of the electronic components in the second quadrant Q2is greater than 3 to make air flow zone in the second quadrant Q2have a sufficient size. Of course, a contrary arrangement is also available, i.e. the ratio of volume of the first channel S1in the first quadrant Q1to volume of the electronic components in the second quadrant Q2is greater than 3.

As abovementioned, volume of the electronic components in the second quadrant Q2is less than volume of the electronic components in the first quadrant Q1. In an aspect of proportional relationship, a ratio of volume of the electronic components in the second quadrant Q2is less than a ratio of volume of the electronic components in the first quadrant Q1.

As for the arrangement of the lower portion, volume of the electronic components in the fourth quadrant Q4is less than volume of the electronic components in the third quadrant Q3, so a sufficient air channel can be kept from the fourth quadrant Q4to the first quadrant Q1. In an aspect of proportional relationship, a ratio of volume of the electronic components in the fourth quadrant Q4to volume of the first channel S1in the fourth quadrant Q4is less than a ratio of volume of the electronic components in the third quadrant Q3to volume of the first channel S1in the third quadrant Q3.

If multiple electronic components are categorized to heat-generating elements, an ideal position of the heat-generating elements is the upper portion, i.e. both the first quadrant Q1and the second quadrant Q2. Thus, the heat-generating elements are arranged in both the first quadrant Q1and the second quadrant Q2. That is, the heat-generating elements may be in contact with cooling airflow at a distal end of the heat dissipating channel to prevent the cooling airflow from being heated first not to affect cooling of other electronic components. The ratio of the number of the heat-generating elements in the first quadrant Q1corresponding to the heat-generating elements in the second quadrant Q2to the number of the heat-generating elements in the second quadrant Q2is between 0 and 0.5 to reduce the number of the heat-generating elements on the same cross-section. This is advantageous to enlarging temperature gradient on the same cross-section and radiating heat from the heat-generating elements to surrounding air. In detail, heat from the heat-generating elements must be radiated to air through thermal radiation, and a temperature difference is one of the key factors. Thus, interference between heat-generating elements must be as less as possible to guarantee the temperature difference between heat-generating elements and air to ensure thermally radiative efficiency.

In the aspect of upward and downward flow of cooling air, volume of the first channel in both the third quadrant Q3and the fourth quadrant Q4is greater than volume of the first channel in the first quadrant Q1and the second quadrant Q2to prevent the cooling airflow from meeting high flow resistance at a starting end not to affect flowing of the cooling airflow.

In general, preferably, the ratio of a cross-sectional area of the electronic components in a radial direction to a cross-sectional area of the heat dissipating channel in a radial direction is between 0 and 0.4, where the ratio 0 means no electronic component on the cross-section, and the ratio 0.4 means avoiding cross-sectional area of the electronic components in a radial direction exceeding half of the heat dissipating channel.

On a single side, such as the first side, the ratio of a cross-sectional area of the electronic components in the first channel S1in a radial direction to a cross-sectional area of the first channel S1in a radial direction is between 0 and 0.3. Contrarily, on the second side, the ratio of a cross-sectional area of the electronic components in the second channel S2in a radial direction to a cross-sectional area of the second channel S2in a radial direction is between 0 and 0.6. In one example, the electronic components on the first side and the second side adopt different proportion of distribution to make one side have better flowing of airflow.

As shown inFIG. 54, the abovementioned proportion may be arranged by biasing the power board51from the axis. A biasing distance G is formed between the power board51and the axis of the heat dissipating channel. The ratio of the biasing distance G to a radius of the heat dissipating channel is between 0.15 and 0.4. Such a biasing distance can adjust the center of gravity to make the equivalent center of gravity falls on the axis of the heat dissipating channel.

FIG. 56is a schematic view of the combination of the power source5and the sleeve21of an embodiment. As shown inFIG. 56, the power board51is configured to incline to the axis of the LED lamp. The side with high flow resistance, such as the side on which more electronic components are mounted, may be arranged to be the upward side of the inclined power board51. The side with low flow resistance, such as the side on which less electronic components are mounted, may be arranged to be the downward side of the inclined power board51. As a result, the side with high flow resistance still have sufficient airflow to pass. The counterweight52may be mounted on the downward side of the power board51according to a tilting status to balance weight on the Y-axis and make the center of gravity of the LED lamp keep on the Y-axis.

As shown inFIGS. 1, 2, 3 and 4, the lamp shell2includes the lamp head23, the lamp neck22and the sleeve21. The lamp head23connects to the lamp neck22which connects to the sleeve21. The sleeve21is located in the heat sink1(in the axial direction of the LED lamp, all or most of the sleeve21, for example, at least 80% of height of the sleeve21, does not exceed the heat sink1). The lamp neck22projects from the heat sink1. Both the sleeve21and the lamp neck22can provide sufficient space to receive the power source5and perform heat dissipation, especially for the power source5of a high power LED lamp (in comparison with a low power LED lamp, a power source of a high power LED lamp has more complicated composition and larger size). The power source5is received in both the lamp neck22and lamp head23. Total height of the lamp neck22and the lamp head23is greater than height of the heat sink1so as to provide more space for receiving the power source5. The heat sink1is separate from both the lamp neck22and the lamp head23(not overlap in the axial direction, the sleeve21is received in the heat sink1). Thus, the power source5in both the lamp neck22and the lamp head23is affected by the heat sink1slightly (heat of the heat sink1would not be conducted to the lamp neck22and the lamp head23along a radial direction). In addition, the configuration of height of the lamp neck22is advantageous to the chimney effect of the first heat dissipating channel7ato guarantee convection efficiency of the first heat dissipating channel7a. In other embodiments, height of the lamp neck22is at least 80% of height of the heat sink1to accomplish the above function. The sleeve21is made of a thermo-isolated material to prevent mutual influence of heat from the fins and the power source.

As shown inFIG. 2, the second air inlet1301is located in a lower portion of the heat sink1and radially corresponds to an inner side or the inside of the heat sink1, i.e. the second air inlet1301radially corresponds to the inner side or the inside of the fins11. The inner side or the inside of the fins11corresponds to an outer wall (a radially inner side of the fins11, which nears or abuts against the sleeve21) of the sleeve21of the lamp shell2. Thus, after convection air flows into the second air inlet1301, it flows upward along the outer wall of the sleeve21to perform convection and radially dissipates heat in the inner side or the inside of the fins11and the outer wall of the sleeve21to implement an effect of thermal isolation. That is, this can prevent heat of the heat sink1is conducted from the outer wall of the sleeve21to the inside of the sleeve21not to affect the power source5. From the above, the second heat dissipating channel7bcan not only enhance heat dissipation of the fins11, but also implement an effect of thermal isolation. Make a positional comparison between the second air inlet1301and the LED chips311, the second air inlet1301is located radially inside all of the LED chips311.

FIG. 57is an enlarged view of portion B inFIG. 2. As shown inFIG. 57, the lamp head23includes a metal portion231and an insulative portion232. Wires of the power source5penetrates through the insulative portion232to connect with an external power supply. The metal portion231connects to the lamp neck22. In detail, as shown inFIG. 58, an inner surface of the metal portion231is provided with a thread through which the lamp neck22can be screwed on with the metal portion231. While the metal portion231is dissipating heat generated from the power source5in the lamp shell2(as described in the above embodiment, at least part of the inner wall of the metal portion231forms a wall of the inner chamber of the lamp shell2, so the thermal conductor directly connects with the metal portion231and the metal portion231can be used for heat dissipation), an outer surface of the metal portion231is formed with a projecting structure2311as shown inFIG. 58to add surface area of the outer surface of the metal portion231and enlarge heat dissipating area of the metal portion231to increase efficiency of heat dissipation. As for the power source5, at least part of the power source5is located in the lamp head23, and at least part of heat generated from the power source5can be dissipated through the lamp head23. The inner wall of the metal portion231may also be formed with a projecting structure to add surface area of the inner chamber of the lamp shell2. In this embodiment, the projecting structure can be implemented by forming a thread on the inner surface of the metal portion231.

Next, please refer toFIGS. 59a˜59candFIG. 60.FIG. 59ais a perspective views of the lamp neck22of one embodiment, andFIG. 59bis another perspective view of the lamp neck22of this embodiment.FIG. 60is a perspective view of the sleeve21of this embodiment. As shown inFIGS. 2, 59a,59band60, the lamp neck22is connected to the sleeve21by engagement. In detail, the sleeve21has a first positioning unit211and the lamp neck22has a second positioning unit221. The sleeve21can be connected with the lamp neck22by engaging the first positioning unit211and the second positioning unit221.

In this embodiment, the first positioning unit211is an engaging portion on the sleeve21, and the second positioning unit221is a latch on the lamp neck22. The engaging portion can fasten with the latch. In other embodiments, alternatively, the first positioning unit211is a latch on the sleeve21, and the second positioning unit221is an engaging portion on the lamp neck22. The engaging portion can fasten with the latch.

In this embodiment, the sleeve21has a connecting portion212. The connecting portion212includes at least two sheet-shaped bodies2121on a circumferential portion of the LED lamp. The first positioning unit211is formed on the sheet-shaped bodies2121. When the lamp neck22engages with the sleeve21, the second positioning unit221is embedded into the first positioning unit211. When embedding, the second positioning unit221exerts radial pressure to the sheet-shaped bodies2121. When the sheet-shaped bodies2121are more than two in number, their radially structural strength would be weakened to make the engagement easier, and the connecting portion212would have a larger amount of radial deformation. In this embodiment, the engaging portion212is a trough or a through hole formed in the sheet-shaped bodies2121.

In this embodiment, two gaps are formed between the two sheet-shaped bodies2121and the gaps constitute a positioning trough213. The lamp neck22has a third positioning unit (plates223and225) corresponding to the positioning trough213. When the sleeve21engages with the lamp neck22, the third positioning unit (plates223and225) is inserted into the positioning trough213to limit the sleeve21to be un-rotatable.

In this embodiment, the connecting portion212is coaxially put in the lamp neck22. By the coaxial connection, both the connecting portion212and the lamp neck22have mutual guiding and supporting effects to make the connection easy, simple and stable.

In this embodiment, both the lamp neck22and the sleeve is an integrated structure (not shown) to simplify a structure of the lamp shell2.

As shown inFIG. 59b, the lamp neck22has a slot224formed between plate223and plate225. In detail, the slot224allows the power board51to be inserted for fixture. In this embodiment, two sets of plates223and225are disposed along the axial direction of the LED lamp to make the LED lamp keep in the axial direction and a gap is kept between the two sets of plates223and225. When the power board51has been inserted into the slot224, convection can be performed between two sides of the power board51through the gap. In this embodiment, when two sets of plates223and225are disposed in the axial direction of the LED lamp, the ratio of length L1of the lower set of plates223and225in the axial direction of the lamp neck22to length L2of the power board51is 1:14˜22. When the ratio falls within this range and the power board51is inserted into the lower slot224, two sides of the power board51are limited by the plates223and225, so the power board51would not tilt to be advantageous to make the power board51easy to align with the other slot224. This can reduce difficulty in assembling.

In this embodiment, the two plates223and225are formed by two parallel ribs. A set of ribs is disposed on an inner wall of the lamp neck22and extends along the axial direction of the lamp neck22. After the power board51has been inserted into the slot224, the ribs are parallel to the power board51.

In this embodiment, the third positioning unit formed by two plates223and225, two opposite sides of the positioning trough213have effects of positioning and guiding.

FIG. 59cis a perspective view of the lamp neck22on an embodiment. As shown inFIG. 59c, in some embodiments, the plates225are of a single set along the axial direction of the LED lamp and with longer length. Such a long slot224formed the plates225can fix the power board51more firmly. In this embodiment, length of the plate225is 15%˜45% of length of the power board51to make the power board51held by the slot224.

In other embodiments, the slot224may also be a trough on an inner wall of the lamp neck22(not shown). Thus, no plate is required for structural simplification.

As shown inFIGS. 59band31, in this embodiment, a first stopping portion226is provided in the lamp neck22to correspond to the power board51. When the power board51is inserted, it will be stopped by the first stopping portion226to prevent the power board51from being excessively pressed and being damaged. On the other hand, the first stopping portion226can keep a gap between the power board51and an end portion of the lamp head23to guarantee convection in the gap.

As shown inFIG. 31, the sleeve21has a second stopping portion215corresponding to the power board51for limiting downward movement of the power board51in the axial direction. Both the first stopping portion226and the second stopping portion215limit two sides of the power board51in the axial direction to fasten the power board51in the axial direction.

As shown inFIGS. 1 and 31, the lamp shell2has an airflow limiting surface214which extends radially outwardly and is located away from the venting hole222. The airflow limiting surface214cloaks at least part of the fins11. When the fins are dissipating heat, hot airflow heated by the part of fins111cloaked by the airflow limiting surface214rises but is blocked by the airflow stopping surface214to change its direction (outward along the airflow stopping surface214). Thus, rising hot airflow is forced to go away from the venting hole222. This can prevent hot air from both gathering around the venting hole222and affecting convection speed of the first heat dissipating channel7a. Also, this arrangement can prevent rising hot air from both being in contact with the metal portion231of the lamp head23and affecting heat dissipation of the metal portion231. Even hot air directly passing the metal portion231to conduct into the inner chamber of the lamp shell2can also be avoided. The airflow stopping surface214may be formed on the sleeve21. As shown inFIG. 12, in another embodiment of the present invention, the airflow stopping surface214may also be formed on the lamp neck22.

As shown inFIG. 31, in this embodiment, upper portions of at least part of the fins11in the axial direction of the LED lamp correspond to the airflow stopping surface214. When the lamp shell2is inserted into the heat sink1, the airflow stopping surface214will have a limiting effect to the lamp shell2. In this embodiment, the fins abut against the airflow stopping surface214.

As shown inFIG. 31, in this embodiment, the sleeve21is made of a material whose thermal conductivity is less than that of the material of which the lamp neck22is made. The airflow stopping surface214is formed on the sleeve21. Height of the heat sink1in the axial direction does not exceed the airflow stopping surface214to reduce contact area between the heat sink1and the lamp neck22. As for the sleeve21, the lower its thermal conductivity is, the less the heat conducted from the heat sink1to the inside of the sleeve21is, and the less the influence to the power source5is. As for the lamp neck22, the less the contact area between the lamp neck22and the heat sink1is, the lower the thermal conductivity is. The lamp neck22has better thermal conductivity than that of the sleeve21. The lamp neck22can dissipate at least part of heat from the power source5. In other embodiments, both the sleeve21and the lamp neck22may adopt the same material, a material with relatively low thermal conductivity, such as plastic.

As shown inFIG. 31, in this embodiment, both a wall of the sleeve21and a wall of the lamp neck22jointly constitute a wall of the inner chamber of the lamp shell2. Height of the heat sink1in the axial direction does not exceed height of the sleeve21to make the heat sink1corresponds to the sleeve21in a radial direction of the LED lamp. That is, the sleeve21has an effect of thermal isolation to prevent heat of the heat sink1from being conducted to the sleeve21, so that electronic components of the power source5world not be affected. All the lamp neck22is higher than a position of the heat sink1. That is, in a radial direction of the LED lamp, the heat sink1does not overlap the lamp neck22. This can make thermal conduction between the heat sink1and the lamp neck22, and prevent heat from the heat sink1to conduct to the inside of the lamp neck22, so that the electronic components therein would not be affected. As a result, in this embodiment, heat conducting efficiency of the wall of the sleeve21is configured to be lower than heat conducting efficiency of the wall of the lamp neck22. Advantages of such configuration are as follows: (1) because heat conducting efficiency of the sleeve21is relatively low, thermal conduction from the heat sink1to the sleeve21can be reduced to prevent electronic components in the sleeve21form being affected by the heat sink1; and (2) because thermal conducting from the heat sink1to the lamp neck22does not need to be considered, heat conducting efficiency of the lamp neck22can be increased to be advantageous to dissipating heat from the electronic components of the power source5through the lamp neck22. This can avoid life shortening of the power source5due to overheating. In this embodiment, in order to make heat conducting efficiency of the wall of the sleeve21be lower than heat conducting efficiency of the wall of the lamp neck22, the sleeve21is made of a material with low thermal conductivity and the lamp neck22is made of a material with relatively high thermal conductivity. To increase thermal conductivity of the lamp neck22, the lamp neck22may be provided with a venting hole222or a heat conducting portion (not shown) such as metal or other materials with high thermal conductivity.

As shown inFIG. 31, the lamp neck22has an upper portion and a lower portion. The venting hole222is located in the upper portion. Cross-sectional area of the upper portion is less than cross-sectional area of the lower portion. Airflow speed in the upper portion is faster than that in the lower portion, so that initial speed of air ejected from the venting hole222can be increased to prevent hot air from gathering around the venting hole222. In this embodiment, cross-sectional area of the lamp neck22upward tapers off in the axial direction to avoid obstruction to air flowing. In this embodiment, cross-sectional area of an inlet of the lower portion of the sleeve21is greater than that of the upper portion of the lamp neck22.

As shown inFIG. 1, the venting hole222of the lamp neck22is of a strip shape and extends along the axial direction of the LED lamp. Because of gravity of the LED lamp itself, the lamp neck22would suffer an axial pulling force. The venting hole222are configured to be of a strip shape extending the axial direction of the LED lamp, so stress concentration caused by the venting hole222in the lamp neck22can be prevented. A maximum diameter of an inscribed circle of the venting hole222is less than 2 mm, preferably, between 1 mm and 1.9 mm. As a result, the venting hole222can prevent bugs from entering and prevent most dust from passing. On the other hand, the vent41can keep better efficiency of air flowing. On the other hand, if the venting hole222is configured to annular extending along an circumferential portion of the lamp neck22, then the lamp neck22may be deformed by weight of the heat sink1to make the venting hole222become larger. This would cause that a maximum diameter of an inscribed circle of the venting hole222is greater than 2 mm, this cannot satisfy the requirement.

As shown inFIG. 21, the venting hole222is outside an outer surface of the metal portion231in radial directions. This can reduce influence to the metal portion231because of rising air ejected from the venting hole222and prevent heat from being conducted back to the lamp shell2.

FIG. 61is a cross-sectional view of the LED lamp of another embodiment.FIG. 62is a schematic view of arrangement of the convection channels in the LED lamp. As shown inFIGS. 61 and 62, in some embodiments, a fundamental structure of the LED lamp is identical to the LED lamp shown inFIG. 1. In some embodiments, the sleeve21has an upper portion and a lower portion. The upper portion is connected to the lower portion through an air guiding surface216. A diameter of cross-section of the air guiding surface216downward tapers off along the axis of the LED lamp (along the convection direction of the first heat dissipating channel7a). That is, the air guiding surface216can guide air in the second heat dissipating channel7btoward the radial outside of the heat sink1so as to make air be in contact with more area of the fins11to bring out more heat of the fins11. The sleeve21includes a first portion and a second portion in the axial direction. The second portion is a part of the sleeve21below the air guiding surface216(including the air guiding surface216). The first portion is the other part of the sleeve21above the air guiding surface216(but not including the air guiding surface216). Electronic components of the power source5, which are located in the second portion of the sleeve21, include heat intolerance elements such as capacitors, especially electrolytic capacitors so as to make the heat intolerance elements work in low temperature environment (near the first air inlet2201). In other embodiments, high heat-generating elements may be disposed in the second portion of the sleeve21, such as resistors, inductors and transformers. As for the second heat dissipating channel7b, when convection air flows into the second heat dissipating channel7band reaches the lower portion of the sleeve21, the convection air would lean against the outer wall of the sleeve21to rise. This can generate an effect of thermal isolation, i.e. heat of the fins11is prevented from being conducted to the inside of the sleeve21so that the heat intolerance elements therein would not be affected. When the convection air continues to rise, the convection air will flow outward along radial directions of the fins11under the guide of the air guiding surface216so as to make the convection air be in contact with more area of the fins11to enhance an effect of heat dissipation of the fins11. In this embodiment, the inner chamber of the sleeve21is of a wide-upper-side-and-narrow-lower-side channel structure. This significantly enhances the chimney effect and promotes air flowing in the sleeve21. In addition, the venting hole222can be designed on the lamp neck22away from the vent to further improve the chimney effect.

FIG. 63is a main view of an embodiment of the LED lamp without the heat sink1.FIG. 64is an exploded view ofFIG. 63. Features mentioned in this embodiment may be applied to the LED lamp ofFIG. 1. As shown inFIG. 63, in some embodiments, an outer wall of the sleeve21is provided with a passage219to make part of convection air pass through the passage219to reach the heat sink1. In this embodiment, the passage219may be a slot at the lower portion of the outer wall of the sleeve21or a hole at the lower portion of the outer wall of the sleeve21. The passage219may be multiple in number. The multiple passages219are radially distributed on the sleeve21. At this time, positions of the blocks217are correspondingly adjusted.

As shown inFIG. 64, the sleeve21is provided with a wire pressing portion210downward projecting from a bottom edge of the sleeve21. The wire pressing portion210is formed with a wire pressing trench2101for allowing the wire connecting the power source5and the light board3to be embedded into the wire pressing trench2101to fix the wire.

As shown inFIG. 64, the sleeve21has a fourth positioning unit2102, and the lamp cover4has a fifth positioning unit46. The fifth positioning unit46corresponds to the fourth positioning unit2102to limit rotation of the sleeve21against the lamp cover4. In detail, the fourth positioning unit2102and the fifth positioning unit46are a positioning hole and a positioning bar, respectively. The positioning bar is inserted into the positioning hole for engagement. It is noted that the positioning bar is not arranged in the axial direction of the sleeve21. Preferably, both the positioning bar and hole are multiple in number. In other embodiments, the fourth positioning unit2102and the fifth positioning unit46are a positioning bar and a positioning hole, respectively. The positioning bar is inserted into the positioning hole for engagement.

Next, please refer toFIG. 1, which shows an outline of the LED lamp of one embodiment. Create a Cartesian coordinate system with the axis of the LED lamp as the y-axis, a radial of the LED lamp as the x-axis and the center of the LED lamp as the origin. A lateral outline of the LED lamp detours around the axis of the LED lamp 360 degrees to turn around to form an contour of the LED lamp (not including the lamp head23). Any point on the outline (usually, the lamp head23is a standard one, thus, here does not include the lamp head23; in detail, the outline is composed of the heat sink1and the lamp head22) meets a formula as follows:
y=−ax3+bx2−cx+K

where K is a constant, range of K is 360˜450, range of a is 0.001˜0.01, range of b is 0.05˜0.3, range of c is 5˜20, preferably, 10˜18, more preferably, 12˜16.

Hereinafter, as an example, values of a, b and c are supposed as follows:
y=−0.0012x3+0.2235x2−14.608x+K

where range of K is 360˜450.

The above formula can be interpreted as any point on the outline falling within a range between two lines of y=−0.0012x3+0.2235x2−14.608x+360 and y=−0.0012x3+0.2235x2−14.608x+450.

In sum, comprehensively considering various factors of an effect of heat dissipation, principles of thermodynamics and fluid mechanics, satisfying this formula can obtain a great effect of heat dissipation.

In detail, in one aspect, when any point on the outline satisfy the above formula, a better match between the LED lamp and a lampshade (especially a conic lampshade) as shown inFIG. 67can be made. In another aspect, when any point on the outline satisfy the above formula, the LED lamp axially tapers off from its bottom to top to make overall width of the LED lamp approximately progressively decreases. For the heat sink1, heat from the LED chips311can be rapidly conducted to the lower portion of the heat sink1to perform heat dissipation. The upper portion of the heat sink1mainly relies upon both radiation and convection to perform heat dissipation. Thus, the lower portion of the heat sink1is configured to have more area to perform thermal conduction (the lower portion of the heat sink1has large width and heat dissipating area). For the lamp neck22, the lamp neck22has a large lower portion and a small upper portion. That is, Cross-sectional area of the lamp neck22axially upward tapers off. When the lamp neck22dissipate heat from the power source5through convection and the venting hole222is located in the upper portion of the lamp neck22, the rising convection airflow would speed up because of tapered cross-sectional area of the lamp neck22. This makes the convection air ejected from the venting hole222have faster initial speed, so ejected air would rapidly leave away from the venting hole222to prevent hot air from gathering near the venting hole222.

In this embodiment, the outline is a continuous line. In other embodiments, the outline may be a multiple sectional line (as shown inFIG. 68)

In this embodiment, the outline is a smooth or approximately smooth curve to avoid forming angles with possibility of cutting hands. On the other hand, this makes convection air flowing along the outside of the LED lamp smoother. In this embodiment, the outline of the LED lamp is a substantially S-shaped curve including a curve on the lamp neck22and a curve on the heat sink1. It is noted that a junction of the lamp neck22and the heat sink1may form an angle which destroys smoothness of the curve. However, in general, overall outline still presents smooth. In addition, LED lamps with the same width, whose outlines are curves, in comparison with a straight line, have more area of an outline surface to provide more area for thermal radiation.

As shown inFIG. 66, which shows an outline of the LED lamp of one embodiment. Create a Cartesian coordinate system with the axis of the LED lamp as the y-axis, a radial of the LED lamp as the x-axis and the center of the LED lamp as the origin. A lateral outline of the LED lamp detours around the axis of the LED lamp 360 degrees to turn around to form a contour of the LED lamp (not including the lamp head23). The outline includes an outline of the LED neck22and an outline of the heat sink1.

The lamp neck22is used for receiving the power source5and primarily adopts convection to implement heat dissipation to the power source5. The outline of the lamp neck22has a slope a which is a constant. As shown inFIG. 66, when the outline of the lamp neck22is a curve, a straight line may represent an approximate slope of the outline of the lamp neck22. For example, a line L1between the top point and the bottom point of the outline of the lamp neck22can be used to represent an outline of the lamp neck22or a line L2between the center of the top and the bottom point of the outline of the lamp neck22can be used to represent an outline of the lamp neck22. In this embodiment, Line L1between the top point and the bottom point of the outline of the lamp neck22is used to represent an outline of the lamp neck22for description.

The heat sink1primarily adopts conduction to implement heat dissipation to the LED chips311. The outline of the heat sink1has a slope b which is a constant. As shown inFIG. 66, when the outline of the heat sink1is a curve, a straight line may represent an approximate slope of the outline of the heat sink1. For example, a line L3between the top point and the bottom point of the outline of the heat sink1can be used to represent an outline of the heat sink1or a line L4between the center of the top and the bottom point of the outline of the heat sink1can be used to represent an outline of the heat sink1. In this embodiment, Line L3between the top point and the bottom point of the outline of the heat sink1is used to represent an outline of the heat sink1for description.

In this embodiment, slope a is greater than slope b or an absolute value of slope a is greater than an absolute value of slope b. Thus, in general, the outline of the lamp neck22is steeper than that of the heat sink1. For the lamp neck22, under a condition of the same space required for installing the power source5, in order to guarantee the chimney effect of convection in the lamp neck22, a certain height of the lamp neck22must be kept. If a slope of the outline of the lamp neck22is gentle (small slope), to keep the same height, internal volume of the lamp neck22would increase. However, it is actually unhelpful to an installing space of the power source5. For the heat sink1, an overall height of the lamp is controlled to guarantee an effect of heat dissipation. Thus, the heat sink1needs to be configured to be gentle (small slope) to control its overall height. In addition, when the heat sink1is gentle (small slope), under a condition of the same area of heat dissipation, the lower portion of the heat sink1would have more area for thermal conduction to the LED chips311.

In this embodiment, slope a is greater than 2, preferably, 2.5˜5, more preferably, 3˜4, the most preferably, 3.2˜3.8, to make the chimney effect of convection in the lamp neck22better.

In this embodiment, slope b is smaller than 3, preferably, 1˜2.5, more preferably, 1.4˜2, the most preferably, 1.5˜1.9, to make the lower portion of the heat sink1have more area for conduction.

In this embodiment, the outline of the Led lamp is a continuous line, i.e. the bottom of the outline of the lamp neck22is connected to the top of the outline of the heat sink1. In other embodiments, the outline may be multiple sectional lines (as shown inFIG. 68). For example, a gap is formed between the bottom of the outline of the lamp neck22and the top of the outlie of the heat sink1. Thus, the overall outline is discontinuous.

In this embodiment, the outline of the lamp neck22is a concave curve. In one example, if a straight line is connected between the top and the bottom of the outline of the lamp neck22, then all of the outline of the lamp neck22is inside the straight line (i.e. the side near the axis of the LED lamp). The outline of the heat sink1is a convex curve. In one example, if a straight line is connected between the top and the bottom of the outline of the heat sink1, then all of the outline of the heat sink1is outside the straight line (i.e. the side away from the axis of the LED lamp). The outline is a smooth or approximately smooth curve to avoid forming angles with possibility of cutting hands. On the other hand, this makes convection air flowing along the outside of the LED lamp smoother. In this embodiment, the outline of the LED lamp is a substantially S-shaped or an inverted S-shaped including a curve on the lamp neck22and a curve on the heat sink1. Both a curve on the lamp neck22and a curve on the heat sink1jointly constitute an S-shaped or an inverted S-shaped curve. It is noted that a junction of the lamp neck22and the heat sink1may form an angle which destroys smoothness of the curve. However, in general, overall outline still presents smooth. In addition, the LED neck22may be separate from the heat sink1(for example, a certain gap is kept between the lamp neck22and the heat sink1). That is, a curve on the lamp neck22and a curve on the heat sink1are discontinuous. However, in general, overall outline still presents smooth. The outline of the lamp neck22is a concave curve, so in the downward section, an enlarging extent of the lamp neck22increases in size to make the final bottom of the lamp neck22have a larger size to connect with the heat sink1. In one example, an initial position of the upper portion of the heat sink1may obtain a larger size. The outline of the heat sink1is a convex curve, so in the upward section, a reducing extent of the heat sink1increases in size to make the size reduction of the lower portion of the heat sink1become gentler and gentler. Thus, the lower portion have larger area of the heat sink1for heat dissipation. In other embodiments, the outline of the lamp neck22may be a straight line and the outline of the heat sink1is a curve. In addition, the straight line may be parallel to the LED lamp. In other embodiments, both the outline of the lamp neck22and the outline of the heat sink1are straight lines or multiple sectional lines.

In this embodiment, any point on the outline of the lamp neck22must meet a formula as follows:
y=−ax+k1+h,

where k1is a constant and h is height of the heat sink1.

any point on the outline of the heat sink1must meet a formula as follows:
y=−bx+k2,

where k2is a constant.

In this embodiment, when overall width of the LED lamp is configured to be between 100 mm and 220 mm, k1is 100˜200 and k2is 100˜200. For example, when maximum overall width of the LED lamp is 200 mm, k1is 140˜150 and k2is 170˜200.

In this embodiment, height of the lamp neck22is greater than 80% of height of the heat sink1. Because the lamp neck22is axially separate from the heat sink1without overlapping, the power source5in the lamp neck22is less affected by the heat sink1. Thus, when height of the lamp neck22is greater than 80% of height of the heat sink1, more space for installing the power source5can be obtained and the power source5is less affected by the heat sink1. In addition, when heat of the power source5in the lamp shell2is dissipated by convection, configuration of height of the lamp neck22can guarantee height of the lamp shell2to guarantee the chimney effect of convection of heat dissipation.

As shown inFIG. 69, which shows the outline of the LED lamp. Create a Cartesian coordinate system with the axis of the LED lamp as the y-axis, a radial of the LED lamp as the x-axis and the center of the LED lamp as the origin. A lateral outline of the LED lamp detours around the axis of the LED lamp 360 degrees to turn around to form a contour of the LED lamp (not including the lamp head23). The outline includes an outline of the lamp neck22and an outline of the heat sink1. As shown inFIG. 69, in this embodiment, the outline of the LED lamp includes a first curved surface and a second curved surface. Both the first curved surface and the second curved surface jointly constitute a curved surface of the outline of the LED lamp. The first curved surface includes the curved surface of the outline of the lamp neck22or the curved surface of both the outline of the lamp neck22and the outline of part of the heat sink1. The second curved surface include the curved surface of the outline of the heat sink1or the curved surface of the outline of part of the heat sink1.

In this embodiment, the outline of the lamp neck22is a smooth or approximately smooth curve and the outline of the heat sink1is a smooth or approximately smooth curve to avoid forming angles with possibility of cutting hands. On the other hand, this makes convection air flowing along the outside of the LED lamp smoother. In this embodiment, the radius of curvature of the outline of the lamp neck22is greater than the radius of curvature of the outline of the heat sink1. It is noted that the phrase “the radius of curvature of the outline of the lamp neck22is greater than the radius of curvature of the outline of the heat sink1” means that the radius of curvature of 60% of the outline of the lamp neck22being greater than the radius of curvature of 60% of the outline of the heat sink1can be deemed as the radius of curvature of the outline of the lamp neck22being greater than the radius of curvature of the outline of the heat sink1.

As shown inFIG. 69, in this embodiment, a radius of curvature of the outline of the lamp neck22is 120 mm˜3000 mm, preferably, 150 mm˜200 mm, more preferably, 160 mm˜190 mm, and the most preferably, 170 mm˜185 mm. A radius of curvature of the outline of the heat sink1is 30 mm˜150 mm, preferably, 70 mm˜130 mm, more preferably, 80 mm˜120 mm, and the most preferably, 90 mm˜110 mm. Based on the abovementioned, if at least 60% of the radius of curvature falls in the range or curvature of a curve which is the most consistent with the outline can be deemed as the radius of curvature of the outline of the lamp neck22and the heat sink1. For example, if a radius of curvature of at least 60% of the outline of the lamp neck22is 180 mm, then the radius of curvature of the lamp neck22can deemed as 180 mm. Based on the abovementioned, it can also be interpreted that a curve similar to an outline can represent curvature of the outline. That is, an outline itself may not be a curve. In some embodiments, considering overall width of the LED lamp, the outline of the lamp neck22and the outline of the heat sink1are separately related to overall width of the LED lamp. If width of the LED lamp (a size of the widest portion of the LED lamp) is L, then the radius of curvature of the outline of the lamp neck22is 0.6 L˜15 L, preferably, 0.75 L˜L, more preferably, 0.8 L˜0.95 L, and the most preferably, 0.85 L˜0.925 L; and the radius of curvature of the outline of the heat sink1is 0.15 L˜0.75 L, preferably, 0.35 L˜0.65 L, more preferably, 0.4 L˜0.6 L, and the most preferably, 0.45 L˜0.55 L. That is, both curvature of the outline of the lamp neck22and curvature of the outline of the heat sink1vary with change of overall width of the LED lamp. In some embodiments, if an outer diameter of the largest portion of the lamp neck22is R, then curvature of the outline of the heat sink1must be greater than L/2-R/2 to guarantee both the heat sink1having sufficient height and the chimney effect of the second heat dissipating channel7b.

In this embodiment, a center angle c occupied by the outline of the lamp neck22is 10˜50 degrees, preferably, 20˜35 degrees, and more preferably, 25˜30 degrees, to guarantee both the lamp neck22having sufficient height and the chimney effect of convection in the lamp neck22.

In this embodiment, a center angle d occupied by the outline of the heat sink1is 40˜120 degrees, preferably, 55˜90 degrees, more preferably, 65˜80 degrees, and the most preferably, 70˜75 degrees, to control overall height of the heat sink1.

As shown inFIG. 70a, which is a schematic view of the combination of the LED lamp and a lampshade of one embodiment. In this embodiment, the lampshade6has a receiving room61in which the LED lamp is accommodated. A lower portion of the receiving room61is open to allow the LED lamp to be installed into the receiving room61from the lower portion of the lampshade6. After heat from the LED lamp is diffused to the receiving room61, and then dissipated outward through the opening by air convection. In this embodiment, when heat of the LED lamp is being dissipated, part of heat is directly delivered to the lampshade6by thermal radiation and the lampshade6further delivers the heat to the outside. Another part of heat is delivered to air between the lampshade6and the LED lamp by conduction and convection, and then delivered to the outside of the lampshade6by convection, conduction or radiation.

As shown inFIG. 70b, which is a schematic view of the combination of the LED lamp and an embodiment of a lampshade6, in this embodiment, the lampshade6is formed with a convection hole62located at an upper portion thereof, such that when heat from the LED lamp is delivered to air in the receiving room61, the air would flow upward to pass through the convection hole62to bring out the hot air.

As shown inFIG. 70c, which is a schematic view of the combination of the LED lamp and an embodiment of a lampshade6, in this embodiment, the lampshade6has a closed receiving room61. After the LED lamp has been installed in the receiving room61, because of isolation with the outside, it would have a dust-proof effect to prevent dust from accumulating inside or outside the LED lamp. After heat from the LED lamp is delivered to air in the receiving room61, the air circles round in the receiving room61, then is delivered to the lampshade6, and finally delivered to the outside through the lampshade6.

In this embodiment, the lampshade6may be made of a metal or plastic material. The former is advantageous to heat dissipation, and the latter would make weight and cost become light and low, respectively. Also, a plastic lampshade may be configured to be light-permeable. When the lampshade6is closed, for a better effect of heat dissipation, a metal material is preferred.

FIG. 65ais an exploded view of the lamp shell of the LED lamp of another embodiment with a different lamp shell20.FIG. 65bis a schematic assembling view ofFIG. 65a.FIG. 65c˜65dare exploded views of the LED lamp.FIG. 65eis a cross-sectional view of the LED lamp ofFIG. 65a. As shown inFIGS. 65a, 65band 65c, in some embodiments, the lamp shell20includes a lamp head230, a lamp neck220and a sleeve210. The lamp head230is screwed with the lamp neck220. The lamp neck220connects to the sleeve210. The sleeve210connects to the heat sink10. In detail, a circumferential edge of the lamp neck220is formed with a breach2230. A protruding bar2110on the sleeve210corresponds to the breach2230. The sleeve210is pushed toward the lamp neck220and then rotate the lamp neck220to fasten with the sleeve210. The heat sink10is formed with a positioning trench1210located on an inner wall of a heat dissipating post120. An engaging trough2140is formed on an inner wall of the sleeve210. The power board510is embedded into the engaging trough2140to be secured. The number of the engaging trough2140depends on shapes of the power board510. For example, when the power board510is of a two-dimensional shape, the number of the engaging trough2140is two. In addition, in another embodiment of the present invention, the engaging trough2140may be configured to be rib-like. Two parallel or perpendicular ribs formed on an edge of an inner wall of the sleeve210can fix the power board510in the sleeve210, but limited to this. The power source50may further include other electronic components such as transformers, capacitors, resistors, inductors, fuses, MOSFETs, etc. When the power board510is inserted into the sleeve210, the power source50would heat up. When heat-generating elements such as transformers, capacitors or MOSFETs are located near the bottom end of the sleeve in layout, i.e. in comparison with other electronic components, these heat-generating elements are relatively adjacent to the inlet of airflow channel of the heat sink10. Because when these heat-generating elements are relatively adjacent to the bottom end of the heat sink10, the path through which cool air flows to these heat-generating elements is the shortest, heat dissipation to the heat-generating elements can be effectively implemented to reduce temperature in the chamber of the lamp shell20and to improve working stability of the LED lamp. The sleeve210is disposed with a positioning bar2120corresponding to the positioning trench1210of the heat sink10. The positioning bar2120is inserted into the positioning trench1210, and the sleeve210is pushed toward the heat sink10to fasten the sleeve210to the heat sink10.

As shown inFIGS. 65a˜65e, when assembling the LED lamp, the lamp head231is screwed up with the lamp neck220first, then the power board510is inserted into the engaging trough2140, the lamp neck220connects to the sleeve210, the positioning bar2120is inserted into the positioning trench1210of the heat sink10to make the sleeve210pushed to the bottom of the central chamber of the heat sink1, and finally, the light board3is fixed on the heat sink1by riveting to fasten the lamp cover40to the heat sink10. When assembling, the invention adopts detachable engagement to simplify assembling and disassembling with guaranteeing connective strength, no part will be damaged when assembling and disassembling, all parts can be repeatedly used to solve the drawbacks of conventional screwing connection, including time consuming, high labor cost and high damage rate in assembling and disassembling parts.

As shown inFIG. 65c, the fins include first fins1110and second fins1120. The first fins1110interlace with the second fins1120at regular intervals. Each second fin1120has a connecting notch150correspondingly engaging with a connecting bar2130of sleeve210to enhance connective strength between the sleeve210and the heat sink10.

As shown inFIGS. 65cand 65b, the sleeve210is of a substantially hollow cylindrical shape. The inner chamber of the sleeve210is a channel formed by a wide upper portion and narrow lower portion (the lower portion of the sleeve210is less than the upper portion thereof in cross-sectional area). The ratio of height to width of the whole sleeve210is greater than 2.5 to make the chimney effect more effective, preferably, the ratio is 2.5˜10. According to the standards of the most common A19, A20 and A67 bulb lamps, overall height H of the sleeve210may be 40˜80 mm. Such a wide-lower-portion-and-narrow-upper-portion structure can enhance the chimney effect to promote air convection in the sleeve210. A top end of the sleeve210is connected to a top flowing passage of the lamp neck220. When heat in the sleeve210gathers to the top thereof, the heat would flow to the venting hole2220of the lamp neck220through the top flowing passage, and then be ejected from the lamp shell20to accomplish heat dissipation. The abovementioned specification of the sleeve210is merely an exemplar embodiment and cannot be limited to this.

The heat dissipating method of the LED lamp:

In this embodiment, the heat dissipating method of the LED lamp includes heat dissipation to both the LED chips311and the power source.

As shown inFIGS. 1, 4 and 6, the heat dissipating method for the LED chips311(heat from the working LED chips311) includes the following steps:

S101: providing a light board3on which the LED chips311are mounted for conducting at least part of heat from the LED chips311to the light board3by thermal conduction; and

S102: providing a heat sink1on which the light board3is mounted for conducting at least part of heat from the LED chips311to the heat sink1through the light board3by thermal conduction and radiating the heated air from the heat sink1to the outside by convection;

The step S102further includes:

a) The heat sink1is provided with fins11. The heat sink1includes a second heat dissipating channel7bwith a second air inlet1301. Convection air flows into the second air inlet1301to enter spaces between the fins11to bring out heat radiated from the fins11to air. The second air inlet1301is located in the lower portion of the heat sink1.

b) The heat sink1is provided with a third heat dissipating channel7cformed between adjacent two of the fins11or between two sheets extending from a single fin22. A radially outer portion between two fins11forms an intake of the third heat dissipating channel7c. Air flows into the third heat dissipating channel7cthrough the radially outer portion of the LED lamp to bring out heat radiated from the fins11to air.

As shown inFIG. 21, in this embodiment, at least one fin11is divided into two portions in a radial direction of the LED lamp, and the two portions are arranged at an interval in a radial direction of the LED lamp so as to form a passage. When the LED lamp is working, convection air may perform thermal convection in the interval to improve efficiency of convection.

When heat dissipation is performed to the LED chips311, preferably, 20˜30 square mm of heat dissipating area of the heat sink per watt of the LED lamp is configured to obtain a balance between an effect of heat dissipation to the LED chips311and both volume and weight of the heat sink1. This can control both volume and weight of the heat sink1under guaranteeing an effect of heat dissipation. In this embodiment, to make the lampshade have more area for heat dissipation, weight of the heat sink1is set to occupy above 50% of overall weight of the LED lamp, preferably, 55%˜65%; and volume of the heat sink1is set to occupy above 20% of overall volume of the LED lamp, preferably, 25%˜50%.

As shown inFIG. 40, when heat from the LED chips311is being dissipated, a projection (projected onto the plane on which the LED chips311are mounted) of at least part of fins11in the height direction (axial direction) is in contact with at least one LED chip311. That is, in the height direction (axial direction), a projection of at least part of the fins11is superposed or overlapped with at least one LED chip311. Thus, a heat conducting path of the LED chips311can be shortened to reduce thermal resistance and to be advantageous to thermal conduction. Preferably, a projection (projected onto the plane on which the LED chips311are mounted) of any fin11in the height direction (axial direction) is in contact with at least one LED chip311.

As shown inFIGS. 1 and 29, when heat from the LED chips311is being dissipated, the light board3has an inner border3002and an outer border3003. Both the inner border3002and the outer border3003extend upward along the axial direction of the LED lamp to form a region. Area of part of the fins11inside the region is greater than area of another part of the fins11outside the region. As a result, most of the fins11correspond to the light board3to enhance utilization rate of the fins11and increase effective heat conducting area of the fins11for the LED chips311.

As shown inFIG. 4, the method for dissipating heat of the working power source includes the following steps:

S201: providing a lamp shell2having a first heat dissipating channel7ain which the power source5is disposed, wherein the first heat dissipating channel7ahas a first air inlet2201and a venting hole222; and

S202: convection air flowing into the first heat dissipating channel7athrough the first air inlet2201, wherein heat from the power source5is radiated to surrounding air, and heated air is ejected from the venting hole222by convection to prevent the power source5from working in high temperature environment.

As shown inFIG. 22, at least one heat-generating element501(a resistor, an inductor, a transformer or a rectifier) is arranged at a position in the first heat dissipating channel7anear the lamp head23. In a projection of in a direction perpendicular to the axis of the LED lamp, heat from at least one heat-generating element501is delivered to the lamp head23by thermal conduction or thermal radiation and the heat of the lamp head23is dissipated to air or the socket connected thereto.

In other embodiments, at least one heat-generating element501is in thermal contact with the lamp head23, at least one heat-generating element501is located in the lamp head23, the heat-generating element501is in contact with the lamp head23through a thermal conductor53, and the heat-generating element501is fastened to the lamp head23through the thermal conductor53. As a result, the thermal conductor53can not only conduct heat to the lamp head23, but also fasten the heat-generating element to prevent the heat-generating element from loosening.

As for design of heat dissipation of the power source5, a position of at least one heat-generating element in the axial direction of the LED lamp is higher than a position of the venting hole222. Most heat from the heat-generating element501higher than the venting hole222is dissipated through the lamp head or other ways.

In addition, at least one heat-generating element and other heat-generating elements are mounted on different sides of the power board51so as to make convection air bring out heat from the heat-generating elements to surrounding air along these two sides.

The assembling method of the LED lamp is described as follows.

As shown inFIG. 2, in an embodiment, the method includes the following steps:

S301: providing a light board3on which the LED chips311are mounted;

S302: providing the heat sink1;

S303: providing the power source5;

S304: providing the lamp shell2;

S305: installing the power source5in the lamp shell2;

S306: installing the lamp shell2on the heat sink1and electrically connecting the power source5with the light board3; and

S307: providing a lamp cover4and fastening the lamp cover4on the heat sink4to cover the light board3.

The order of the above steps can be adjusted according to actual requirements. After the step S304, the light board3is attached on the heat sink1to form an integrated body.

In the step S304, providing the lamp shell2, the lamp head23and the lamp neck22are provided with corresponding threads to allow the lamp head23to screw with the lamp neck22to implement connection.

In the step S307, the sleeve21of the lamp shell2is detachably engaged with the heat sink1. Here, after the lamp shell2has been assembled, the sleeve21with the lamp shell2as a whole connects to the heat sink1. In an embodiment of the present invention, the sleeve21is connected to the heat sink1first, and then the other elements of the lamp shell2are fixed to the sleeve21, i.e. the lamp neck22is connected to the sleeve21.

As shown inFIGS. 31 and 60, the heat sink1has a center hole and the sleeve is formed with a block217on a surface thereof. The block217has a first limiting side2171disposed and corresponding to an edge of outer surface of the sleeve21. A distance between two fins11in a radially inner portion is greater than a width of the block217. When the sleeve21in inserted into the center hole of the heat sink1, the block217aligns with an interval between two fins11to be inserted into the heat sink1until the first limiting side2171exceeds the bottom of the fins11in the axial direction of the LED lamp. At this time, rotate the sleeve21to make the first limiting side2171abut against the bottom of the fins11. In addition, the sleeve21may have a second limiting side218. When the first limiting side2171abuts against the bottom of the fins11, the second limiting side218abuts against the top of the fins11. As a result, the sleeve21is connected to the heat sink1without any other external elements such as screws. When disassembling, reverse the above steps.

Preferably, the sleeve21is provided with a third limiting side2172at a side of the block217in a circumferential direction for limiting rotation of the fins11. When the sleeve21is installed to the heat sink1, the block217aligns with an interval between two fins11to be inserted into the heat sink1until the first limiting side2171exceeds the bottom of the fins11in the axial direction of the LED lamp. At this time, rotate the sleeve21to make the first limiting side2171abut against the bottom of the fins11and keep rotating until a lateral side of the fins11abuts against the third limiting side2172to avoid over-rotation which causes dislocation between the first limiting side2171and the fins11.

As shown inFIGS. 59a˜59band60, the sleeve21has a first positioning unit211and the lamp neck22has a second positioning unit221. The first positioning unit211engages with the second positioning unit221. In detail, the first positioning unit211is an engaging portion on the sleeve21and the second positioning unit221is a latch on the lamp neck22.

As shown inFIGS. 31˜33, in the step S308, the lamp cover4is provided with a latch46and the heat sink1is provided with a hole corresponding thereto. The lamp cover4is fastened to a back134of the base13of heat sink1by inserting the latch46into the hole.

FIG. 71is a layout diagram of the LED module of an embodiment.FIG. 72is an enlarged view of portion D inFIG. 71.FIG. 73is an enlarged view of the LED module of another embodiment. The LED modules shown in bothFIGS. 71 and 72may be applied to the LED lamp ofFIG. 1. As shown inFIGS. 71˜73, the LED module70includes at least one LED unit710. The LED units710are two or more in number and electrically connected in parallel. Each LED unit710includes at least one LED711. When an LED unit710includes multiple LEDs711, the LEDs711in the same LED unit710are electrically connected in series. A positive terminal of the first LED711is coupled to a positive terminal of the LED unit710. A negative terminal of the first LED711is coupled to next or a second LED711. A positive terminal of the last LED711is coupled to a negative terminal of a former LED711. A negative terminal of the last LED711is coupled to a negative terminal of the LED unit710.

As shown inFIG. 71, in some embodiments, the LED module70includes five LED units710. As shown in the figure, the LED module70are distributed on two circumferences, i.e. an inner circumference and an outer circumference. The inner circumference is disposed with two complete LED units710, and the outer circumference is disposed with two complete LED units710, too. As for the fifth LED unit710, most LEDs611thereof are located on the outer circumference and a few thereof are located on the inner circumference. That is, the LEDs711of the fifth LED unit710on the inner circumference is less than the LEDs711on the outer circumference.

As shown inFIG. 73, in some embodiments, the LED module70includes ten LED units710. In the shown embodiment as an example, the LED module70is distributed on three circles, i.e. an inner circle, a middle circle and an outer circle. There are two, four and three complete LED units710on the inner circle, the outer circle and the middle circle, respectively. Most of the tenth LED unit710is mounted on the inner circle, and a few of the tenth LED unit710is mounted on the outer circle. That is, the LEDs711of the tenth LED unit710on the inner circle are greater than the LEDs711of the tenth LED unit710on the outer circle in number.

Preferably, the number of the LEDs711of the LED unit710is 10˜20, more preferably, 12˜16.

As shown inFIGS. 71, 72 and 73, the LEDs711are mounted on the light board3along a circumferential direction of the light board3. When the LEDs711of the same LED unit710are on the same circle, all LEDs711are connected by a first wire712. That is, connecting in series of the LEDs711on the same circle is implemented by the first wire712. If the LEDs711of the same LED unit710are divided into two groups, one group is located on a circle and the other group is located on another circle, then the LEDs711of the same LED unit710on the same circle are connected by the first wire712, and the LEDs711of the same LED unit710on another circle are connected by a second wire713. The second wire713is less than the first wire in width to provide a better layout for the LEDs711. If width of the second wire713is excessively wide, then pitch of the LEDs711on the corresponding circle would be affected to become larger than the others.

As shown inFIGS. 71, 72 and 73, width of the first wire712is at least greater than width of the LEDs711(LED chips311). The first wire712adopts a metal material with great thermal conductivity to be advantageous to heat dissipation of the LEDs711(LED chips311). Because width of the first wire712is at least greater than width of the LEDs711(LED chips311), it is more advantageous to installation of the LEDs711and forming electrical connection with the first wire.

As shown inFIGS. 71, 72 and 73, the LEDs711are distributed on different circles on the light board. That is, there are at least two circles for mounting LEDs711. The two circles are approximately concentric. The LEDs711on the innermost or the outermost circle are connected in series by the first wire712. At least part of the first wire712connecting the LEDs711on the innermost or the outermost circle is greater than the other part thereof in width. Because no LED711is mounted outside the outermost circle or inside the innermost circle, width of the first wire712connecting the LEDs711on the innermost or the outermost circle has no limit. Thus, the first wire712connecting the LEDs711on the innermost or the outermost circle may be provided with an extension portion7121on a radial outside or inside to increase its width and area. This is advantageous to be heat dissipation.FIG. 73as an example, it has three circles for mounting the LEDs711, wherein width of the first wire712on the innermost or outermost circle is greater than width of the first wire712on the middle circle.

As shown inFIGS. 71 and 72, the light board3is provided with fixing holes301. The light board3is fastened onto the base13by inserting screws or rivets into the fixing holes301. The fixing holes occupy some area, so parts of the first wire712corresponding to the fixing holes712must detour around the fixing holes301. And width of these detouring parts of the first wire712is less than width of the first wire712with the extension portion7121so as to reduce extent of detour of the first wire712.

As shown inFIGS. 71 and 72, in a direction perpendicular to the light board3, area of a single LED711is M1, and area of part of the first wire712encompassed by a projection of a single LED711projected onto the light board3is M2, which satisfies the following relationship: M2:M1=1:(0.85˜0.96), preferably, M2:M1=1:(0.9˜0.96), so as to make the LEDs711be able to correspond to more area of the first wire711for heat dissipation.

As shown inFIGS. 71 and 72, different LED units710are coupled by a third wire714. The third wire714connects positive electrodes of the first LEDs711of two different LED units710or the third wire714connects negative electrodes of the last LEDs711of two different LED units710. The third wire714is less than the first wire712in width.

As shown inFIGS. 71 and 72, the LED module70includes two electrode terminals such as the positive terminal701and the negative terminal702. Both the positive terminal701and the negative terminal702are located radially inside all of the LEDs711, the first wire712, the second wire713and the third wire714. In other embodiments, alternatively, both the positive terminal701and the negative terminal702are located radially outside all of the LEDs711, the first wire712, the second wire713and the third wire714. Both the positive terminal701and the negative terminal702are used to connect with the power source5. In addition, both the positive terminal701and the negative terminal702have different shapes for distinction.

As shown inFIGS. 74 to 82, the present disclosure provides a power supply module for LED lamp. The power supply module includes input ends (ACN, ACL) for receiving AC driving signal; a first rectifying circuit100for converting the AC driving signal into rectified signal; a filtering200for converting the rectified signal into filtered signal; a power converter400for converting the filtered signals into power signal which is capable of lighting up an LED light source500; and a bias generating circuit600electrically connected to the input ends (ACN, ACL) and the power converter400for performing buck-conversion to the AC driving signal to generate a working voltage of the power converter400.

In the power supply module of certain embodiments, the bias generating circuit600performs buck-conversion to the AC driving signal and converts the AC driving signal into a working voltage of the power converter400. The working voltage is provided to the power converter400so that the power converter400can drive the LED light source500to emit light. It can be seen that, by utilizing the bias generating circuit600to perform active power conversion to externally input AC driving signal, to the working voltage can be generated rapidly generate the so as to effectively improve starting speed of an LED lamp.

When using the power supply module as shown inFIGS. 75 to 82, starting speed of HID-LED can be reduced to be about 60 ms, which possesses a very high value of application and very great experience of using.

The power supply module can be applied to high power LED lamps. Output power of the power converter400may be above 30 W. As shown inFIG. 2, the input ends (ACN, ACL) may be two ends of the power supply module: a first end ACL and a second end ACN. The AC driving signal is input through the two ends. The AC driving signal may be AC signal of 220V or any other voltage values. Of course, the input ends (ACN, ACL) may have more than two ends, for example, four ends. It is not limited as long as AC power can be input.

In this embodiment, the first rectifying circuit100may be a bridge rectifier. As shown inFIG. 76, which is a circuit diagram of a rectifying circuit and a filtering circuit of an embodiment of the invention, the first rectifying circuit100includes diodes D7, D8, D9and D10. The first rectifying circuit100performs full wave rectification to the AC driving signal to generate DC driving signal (DC power).

In detail, as shown inFIG. 76, anodes of diodes D7, D9are electrically connected to a first end of the filtering circuit200, cathodes of diodes D7, D9are electrically connected to anodes of diodes D8, D10, and cathodes of diodes D8, D10are electrically connected to a second end of the filtering circuit200. Contacts of diodes D7and D8are electrically connected to the first end ACL. A cathode of diode D8is electrically connected to a cathode of diode D10. Contacts of diodes D9and D10are electrically connected to the second end ACN.

In addition, the first rectifying circuit100may also be any other types of full wave rectifier or half wave rectifier, which can also accomplish the desired function.

In this embodiment, the filtering circuit200includes capacitors C1, C2and an inductor L1. Frist ends of both capacitor C1and inductor L1serve as the second end of the filtering circuit200to electrically connect with cathodes of diodes D8and D10. The second end of inductor L1is electrically connected to the first end of capacitor C1. The second ends of capacitors C1and C2serve as the first end of the filtering circuit200to electrically connect with anodes of diodes D7and D9. The filtering circuit200receives the DC power (the rectified signal) rectified by the first rectifying circuit100and filters high frequency components of the DC power. The DC power filtered by the filtering circuit200is a relatively flat DC waveform. The filtered signal is sent to a post-stage circuit through connecting ends30land302.

In some embodiments, the filtering circuit200may include only capacitor C1to implement filtration without affecting the desired function of the invention.

An electro-magnetic interference (EMI) reduction circuit900may be disposed between the input ends (ACN, ACL) and the rectifying circuit100. The EMI reduction circuit900can reduce influence to the driving signal from an interference magnetic field. In the EMI reduction circuit900, a power line (including a main line and/or a branch of the main line) electrically connected to two ends of the input ends ACN, ACL is electrically connected with an excitation coil LF2connecting a resistor branch (e.g. a branch at which resistor R1is located) and capacitor branches (e.g. branches at which capacitors CX1, CX2, CX3are located), and separately electrically connecting inductor Li1, Li2at two branches.

Of course, the EMI reduction circuit900may adopt an EMI filter having multiple filtering elements. In detail, the EMI filter has differential mode capacitors, common mode inductors, and common mode capacitors.

In this embodiment, the power converter400converts the filtered signal into an electrical signal which is capable of lighting up the LED light source500. The power converter400may change voltage level of the filtered signal to generate DC driving signal with target voltage value. The power converter400has an output end for outputting DC driving signal with target voltage values.

In addition, the branch electrically connected to the input ends ACN, ACL may further be connected with a fuse F1in series. The fuse F1may be a current fuse or a temperature fuse.

FIG. 78is a circuit diagram of a power converter of an embodiment of the invention. As shown inFIGS. 74 and 78, the power converter400receives signal from a pre-stage circuit through the connecting end401,402, and the power signal are provided to a post-stage through the connecting ends5001,5002. The power converter400may adopt a PWM (Pulse Width Modulation) circuit, which controls pulse width to output target signal. In detail, the power converter400includes a controller U2, a power switch Q2, a transformer T2and a diode D10. Controller U2, power switch Q2, diode D10and an energy storage coil (a coil of the transformer T2, which is electrically connected between the power switch Q2and the connecting end5002) cooperate to output power signal (DC driving signal) with required voltage and/or current. The controller U2is activated by a working voltage VCC provided by the bias generating circuit600to output PWM control signal to control switching of the power switch Q2, so that the energy storage coil repeatedly charge and discharge in response to the switching state of power switch and the continuity of the current can be maintained through diode D4(which is operated as a flyback diode), and thus generate the required power signal between the connecting ends5001,5002.

Power switch Q2may be a MOSFET. A first end (power end) of controller U2electrically connects to an output end of the bias generating circuit600. A second end of controller U2electrically connects to an end of transformer T2. An end of the energy storage coil of transformer T2electrically connects to a negative end (i.e. connecting end5002) of the DC output ends and the other end thereof electrically connects to an anode of diode D4. An anode of diode D4electrically connects to a positive end (i.e. the connecting end5001) of the DC output ends. An end of the induction coil of transformer T2electrically connects to a second end of controller U2and the other end of the induction coil is grounded. A third end of controller U2electrically connects to a control end of power switch Q2through resistor R9. A first end of power switch Q2electrically connects to a connecting point between diode D4and transformer T2, and a second end of power switch Q2connects to a fourth end of controller U2. Power converter400may be further provided with a sampling circuit to sample its working status and serve as a reference of output signal of the controller U2.

For example, the sampling circuit includes resistors R8, R10, capacitor C6and an induction coil of the transformer T2. The controller U2may sample voltage of the main line from resistor R8and capacitor C6through its first end, sample output current from the induction coil through its second end and sample current flowing through the power switch Q2from an end of resistor R10through its fourth end. Configuration of the sampling circuit is related to the control manner of the controller U2, the invention is not limited to this embodiment.

In this embodiment, at least one end of the switch controller U3electrically connects to a branch at which inductor L2is located. A filtering element and/or current stabilizer may be added between the switch controller and the inductor. The present invention is not limited thereto.

To reduce both influence resulting from harmonic to circuit properties and conversion loss, a power factor correction (PFC) circuit300may be disposed between the power converter400and filtering circuit200. The PFC circuit300can increase power factors of the filtered signal by adjusting signal properties (e.g. phase, level or frequency) of the filtered signal. PFC circuit300electrically connects to an output end of bias generating circuit600. In detail, PFC circuit300may be an active PFC circuit.

FIG. 77is a circuit diagram of a PFC circuit of an embodiment of the invention. As shown inFIG. 77, PFC circuit300receives signal from the filtering circuit300through the connecting ends301,302and sends corrected signal to the post-stage power converter400through connecting ends401,402. PFC circuit300includes a controller U1, a power switch Q1electrically connected to controller U1, a transformer T1and a diode D3. Power switch Q1may be a MOSFET. A first end (power end) of the controller U1electrically connects to an output end607of bias generating circuit600. A second end of controller U1electrically connects to an end of transformer T1. A coil of transformer T1electrically connects to a main branch in series. The other end of the coil electrically connected to a second end of controller U1is grounded. A positive end (also called connecting end5001) of the DC output ends electrically connects to the main branch. Diode D3is electrically connected in the branch in series. An anode of diode D3electrically connects to both an end of transformer T1and the filtering circuit200, and a cathode thereof electrically connects to connecting end401for electrically connecting to both power converter400and connecting end5001. A third end of controller U1electrically connects to power switch Q1. An end of power switch Q1electrically connects to a fifth electrically connecting point between diode D3and transformer T1. Controller U1may further electrically connects to a sampling circuit (a connecting point between resistor R2and capacitor C3electrically connects to the controller U1, and capacitor C3electrically connects to resistor R3in parallel) and other circuits as shown inFIG. 77.

It should be noted that, the PFC circuit may have various implementation manners or circuit configurations, all which can be applied to the invention, so they would not be described here.

FIG. 79is a circuit diagram of a bias generating circuit of the first embodiment of the invention. As shown inFIGS. 75 and 79, bias generating circuit600amay include an electricity obtainer610, a switch controller U3and an energy storage flyback unit630. Electricity obtainer610electrically connects to both the input ends (ACN, ACL) and switch controller U3. Switch controller U3electrically connects to energy storage unit630having an output end607for outputting a working voltage (VCC). Output end607electrically connects to power converter400to provide the working voltage (VCC) to the power converter400.

Switch controller U3controls switching frequency of the energy storage unit630according to an electricity obtaining signal from the electricity obtainer610to generate the working voltage of the power converter400and uses the output end607to output the working voltage to the power converter400. The switch controller U3is activated by responding to the electricity obtaining signal from the electricity obtainer610and repeatedly switches on and off to periodically charge and discharge by controlling conducting time of the energy storage unit630. And diode D5is used to keep flyback. Thus, the working voltage of the power converter400is formed and is output to the power converter400through the output end607.

In an embodiment, the electricity obtainer610can convert AC driving signal into DC electricity obtaining signal which are equal to the AC driving signal. As shown inFIGS. 75 and 79, electricity obtainer610can be implemented by a second rectifying circuit (hereinafter “second rectifying circuit610”). Second rectifying circuit610includes a first diode D1and a second diode D2, which are electrically connected in series with opposite polarity (i.e. cathodes of diodes D1and D2are electrically connected together). Second rectifying circuit610has an electricity obtaining end601between diodes D1and D2. The electricity obtaining end601electrically connects to the switch controller U3. By the opposite polarity, the two diodes D1and D2rectify the AC driving signal to output DC driving signal at the electricity obtaining end601.

In detail, the electricity obtaining end601further electrically connects to an end of first capacitor C9, and the other end thereof electrically connects to the ground end GND. Switch controller U3electrically connects to an end of inductor L2, and the other end thereof connects to the output end607. Inductor L2can perform both energy storage and release and maintain the current continuity when switch controller U3is switching.

In this embodiment, energy storage flyback unit630may include an inductor L2, a third diode D5and a second capacitor C11. A cathode of the third diode D5connects to a connecting end603disposed between the switch controller U3and inductor L2. An anode of third diode D5connects to ground end GND. An end of second capacitor C11electrically connects to a second connecting end604disposed between inductor L2and the output end607. The other end of second capacitor C11electrically connects to the ground end GND. an end of a load resistor electrically connects to a third connecting end (not shown inFIG. 75) disposed between the second connecting end604and the output end607. The other end of the load resistor electrically connects to ground end GND.

Further, switch controller U3may be a MOSFET switch or an IC ship integrated with a MOSFET switch. Of course, in some embodiments, switch controller U3may be a BJT switch. Switch controller U3has multiple connecting ends (also called connecting port). An electricity obtaining branch is formed between the electricity obtaining end601and the ground end GND. The first capacitor C9is connected in the electricity obtaining branch in series. At least one connecting end of switch controller U3electrically connects to the electricity obtaining end601through the electricity obtaining branch. A branch at which both the electricity obtaining branch and capacitor C9are located electrically connects to the electricity obtaining end601through the fourth connecting end602. The ground end GND electrically connected to a grounding line640. All of the third diode D5, the second capacitor C11and the load resistor electrically connect to the grounding line640.

The bias generating circuit600may be further provided with a sampling circuit to sample its working status and to be a reference of output signal of the switch controller. In addition, in the practical application, switch controller U3may be a chip or IC integrated with at least a control circuit and a power switch, but the present invention is not limited thereto.

For example, the sampling circuit may include a first sampling circuit650and a second sampling circuit620. First sampling circuit650electrically connects to both the electricity obtaining end601(forming a connecting point605inFIG. 79) and switch controller U3. The second sampling circuit620electrically connects to both the output end607and switch controller U3. Switch controller U3outputs a stable working voltage according to sampling signal from both the first sampling circuit650and second sampling circuit620. Configuration of the sampling circuit is related to the control manner of switch controller U3, the invention is not limited to this.FIG. 79is a circuit diagram of the bias generating circuit of the first embodiment of the invention.

In other embodiments, the bias generating circuit may also be used for providing a working voltage to a temperature sensing circuit700.FIG. 80is a circuit diagram of the bias generating circuit of the second embodiment of the invention.FIG. 81is a circuit diagram of a temperature sensing circuit of an embodiment of the invention. As shown inFIGS. 80 and 81, the temperature sensing circuit700electrically connects to power converter400for sending temperature detecting signal to power converter400. The temperature sensing circuit700has a temperature sensor electrically connecting to bias generating circuit600bto make bias generating circuit600bprovide a working voltage to temperature sensing circuit600b.

In this embodiment, in comparison with the embodiment shown inFIG. 79, the bias generating circuit600bof this embodiment further includes a transistor Q3, a diode D6, a resistor R12and a capacitor C10. Transistor Q3may be a BJT as an example (hereinafter refer as BJT Q3). The temperature detector700electrically connects to BJT Q3of the bias generating circuit600b. The collector of BJT Q3electrically connects to output end607. The base of BJT Q3electrically connects to the grounding line with the ground end GND.

The temperature sensing circuit700is activated by responding to the working voltage provided by the bias generating circuit600bthrough the connecting ends701and702and feeds temperature data (Vtemp) back to the controller U2of the power converter400. When a temperature exceeds a threshold value (indicating a situation of overheating), the controller U2of the power converter400would reduce output power to decrease temperature and guarantee the safety during operation.

Moreover, as shown inFIG. 82, the temperature sensing circuit700further electrically connects to a temperature compensator800.FIG. 82is circuit diagram of a temperature compensator of an embodiment of the invention. Temperature sensing circuit700electrically connects between temperature compensator800and bias generating circuit600b. Temperature compensator800electrically connects to power converter400.

Temperature compensator800makes a reference temperature of a free end of the temperature sensing circuit more reasonable. The temperature compensator800in this embodiment can be implemented by a comparator CP (but not limited to this). An input end of comparator CP receives a voltage, indicating a temperature information, through connecting end801and compares the voltage indicating the temperature information with a reference voltage Vref of another input end of comparator CP, such that whether the temperature sensed by the temperature sensing circuit700exceeds a threshold value can be determined and a temperature sensing result signal Vtemp indicating whether the sensed temperature exceeds a threshold value is generated at an output end of the comparator CP. The output end of the temperature compensator800electrically connects to the controller U2of the power converter400to make the temperature sensing result signal Vtemp fed back to controller U2of power converter400, so that controller U2can adjust the output power depending on the system environment temperature.

In another embodiment, the temperature compensator800may have a regulator diode and a thermistor. After the thermistor, the temperature compensator800electrically connects to an amplifier through an adjustable potentiometer. A negative end of the amplifier electrically connects to an output end of the temperature compensator800.

In detail, a circuit diagram of the temperature compensator800may be as shown inFIG. 82. It should be noted that, the temperature compensator800can be implemented by various manners. The invention is not limited to the circuit shown inFIG. 82.

The invention further provides a high power LED lamp including an LED light source500and a power supply module as abovementioned connecting with the LED light source500. In some embodiments, the high power LED lamp means all types of LED lamps whose output power exceeds 30 w, LED lamps which are equivalent to xenon lamps with output power of at least 30 W or LED lamps using high power lamp beads (e.g. lamp beads with rated current above 20 mA).

All digital values mentioned in the description include all values between an upper limit and a lower limit with upper or lower values of increment or decrement by one unit, an interval of at least two units between any lower value and its higher value is available. For example, if a value of a recited quantity of an element or a process variable (e.g. temperature, pressure, time, etc.) is between 1 and 90, preferably, between 20 and 80, more preferably, between 30 and 70, it means inclusion of between 15 and 85, between 22 and 68, between 43 and 51, between 30 and 32, etc. For a value less than 1, one unit may be properly deemed as 0.0001, 0.001, 0.01 and 0.1. This merely intents to clearly express exemplary values. That is, all values and their combinations between the lowest value and the highest value are included in ranges described in the specification.

Unless otherwise defined, all ranges used herein include two end points and all numbers therebetween. The terms “approximately”, “about” or “similar” associated with the ranges are suitable for the two endpoints of the range. Thus, “about 20 to 30” intents to cover “about 20 to about 30”, and at least includes the two endpoints indicated.

Multiple elements, compositions, parts or steps can be provided by a single integrated element, composition, part or step. Contrarily, a single integrated element, composition, part or step can be divided into multiple separate elements, compositions, parts or steps. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be understood that the above description is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. Although the present disclosure is illustrated and described with reference to specific embodiments, those skilled in the art will understand that many variations and modifications are readily attainable without departing from the spirit and scope thereof as defined by the appended claims and their legal equivalents.

The above depiction has been described with reference to the accompanying drawings, in which exemplary embodiments of the disclosure are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.