An LED lamp including a lamp housing, an LED light source, a heat sink and a control circuit. The lamp housing has an accommodating space, a plurality of air inlets and a plurality of air outlets, wherein the accommodating space joins an environment through the air inlets and the air outlets. The LED light source and the heat sink are disposed in the accommodating space and the heat sink is connected with the LED light source. The heat sink includes a pedestal and a plurality of heat dissipation fins connected to the pedestal. An air convection channel is located between any two adjacent heat dissipation fins. Air from the environment flows into the accommodating space, passes through the air convection channel, and leaves the accommodating space via the air outlets sequentially. The control circuit is disposed in the accommodating space and connected to the LED light source.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Chinese application serial no. 2007101411631, filed on Aug. 13, 2007. All disclosure of the Chinese application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light-emitting diode lamp (LED lamp), more particularly, relates to an LED lamp with good heat dissipation performance.

2. Description of the Related Art

LEDs are semiconductor devices. The light emitting chips are mainly made of a compound semiconductor material containing III-V group chemical elements, for example, GaP, GaAs, and the like, and function on the principle of converting electric energy to light. That is to say, the compound semiconductor is powered to release excessive energy through the combination of electrons and holes, so as to emit photon (light). The LED can emit light without being heated or does not discharge to emit light. Therefore, the lifespan of the LED is up to 100,000 hours, and an idling time is not required. In addition, the LED has advantages of quick response speed (approximately 10−9seconds), small volume, power-saving, low pollution, high reliability, and ease mass production. Thus, the LEDs have been intensively used in many fields, for example, light source and illumination device in large-scale bulletin boards, traffic lights, cellular phones, scanners, fax machines, etc.

Currently, the light emitting brightness and efficiency of the LEDs are continuously improved, and meanwhile the white LEDs with high brightness are successfully put into mass production, so the white LEDs have been gradually used in illumination devices such as indoor illumination and outdoor street lamp. Generally, heat dissipation performance is important to high power LEDs. If LEDs operates under high temperature, the brightness that the LED light can provide may be reduced and the life span thereof is reduced. Therefore, how to enhance heat dissipation performance of LEDs is an important topic for research and development people.

SUMMARY OF THE INVENTION

The present invention provided an LED with good heat dissipation performance and long life span.

The present invention provides an LED including a lamp housing, an LED light source, a heat sink and a control circuit. The lamp housing has an accommodating space, a plurality of air inlets and a plurality of air outlets, and the accommodating space joins an environment through the air inlets and air outlets. The LED light source and the heat sink are disposed in the accommodating space, and the heat sink is connected to the LED light source, wherein the heat sink includes a pedestal and a plurality of heat dissipation fins connected to the pedestal. There is an air convection channel between any two adjacent heat dissipation fins. An air convection channel is located between any two adjacent heat dissipation fins, wherein air from the environment is suitable for flowing into the accommodating space via the air inlets, passing through the air convection channels, and leaving the accommodating space via the air outlets. The control circuit is disposed in the lamp housing and is electrically connected to the LED light source.

In an embodiment of the present invention, the lamp housing includes a first cap, a lampshade, a second cap and a conductive plug for accommodating the heat sink. The lampshade is connected to the first cap, and the LED light source is disposed in the lampshade. The second cap is connected to the first cap, so that the first cap is disposed between the lampshade and the second cap. The plug is connected to the second cap, so that the second cap is disposed between the conductive plug and the first cap.

In an embodiment of the present invention, the material of the first cap includes insulation material, such as insulation material with doped zinc oxide.

In an embodiment of the present invention, the material of the second cap includes insulation material, such as insulation material with doped zinc oxide.

In an embodiment of the present invention, the first cap has air inlets, and the second cap has air outlets, wherein each of the air inlets may be an opening with or without barricade, while each of the air outlets may be an opening with or without barricade.

In an embodiment of the present invention, each of the air inlets is a slot-shaped air inlet, and the slot-shaped air inlets are arranged in grating. In addition, each of the slot-shaped air inlets is corresponding to one of the air convection channels of the heat sink, respectively.

In an embodiment of the present invention, the first cap has air outlets, and the second cap has air inlets, wherein each of the air inlets may be an opening with or without barricade, while each of the air outlets may be an opening with or without barricade.

In an embodiment of the present invention, each of the air outlets is a slot-shaped air inlet, and the slot-shaped air outlets are arranged in grating. In addition, each of the slot-shaped air outlets is corresponding to one of the air convection channels of the heat sink, respectively.

In an embodiment of the present invention, the LED light source is an LED package or other types of LED light sources.

In an embodiment of the present invention, the materials of the pedestal and heat dissipation fins are same or different from each other.

In an embodiment of the present invention, the control circuit is a circuit board.

In an embodiment of the present invention, the above circuit board has at least a through hole allowing air to flow within the accommodating space.

In an embodiment of the present invention, the LED lamp may further includes a fan disposed in the accommodating space, wherein the air from the environment is driven by the fan to flow into the accommodating space via the air inlets, pass through the air convection channels, and leave the accommodating space via the air outlets in sequence.

In an embodiment of the present invention, the fan is disposed on the pedestal, and the fan is surrounded by the heat dissipation fins.

In an embodiment of the present invention, the fan and the LED light source are disposed on two opposite sides of the pedestal, respectively.

Since heat generated from the LED lamp of the present invention is capable of removing by the built-in heat sink and the air convection such that the operation temperature of the LED lamp can be maintained within an acceptable range. In other words, the LED lamp of the present invention is not damaged due to over-heating.

DESCRIPTION OF EMBODIMENTS

The First Embodiment

FIG. 1is a diagram of an LED lamp of the first embodiment of the present invention. With reference toFIG. 1, the LED lamp100of the present embodiment includes a lamp housing110, an LED light source120, a heat sink130and a control circuit140. The lamp housing110has an accommodating space110a, a plurality of air inlets110band a plurality of air outlets110c, and the accommodating space110ajoins the environment through the air inlets110band air outlets110c. The LED light source120and the heat sink130are both disposed in the accommodating space110a, and the heat sink130is connected to the LED light source120, wherein the heat sink130has a pedestal132and a plurality of heat dissipation fins134connected to the pedestal132. As shown inFIG. 1, an air convection channel136is formed between any two adjacent heat dissipation fins134, and air from the environment is suitable for flowing into the accommodating space110avia the air inlets110b, passing through the air convection channel136, and leaving the accommodating space110avia the air outlets110csequentially. In addition, the control circuit140is disposed in the accommodating space110aof the lamp housing110and is electrically connected to the LED light source120.

The structure of the lamp housing110, the LED light source120, the heat sink130and the control circuit140may have many varieties, and the structural design schematically shown inFIG. 1is only illustrated as an example for one skilled in the art to implement the present invention, rather than limiting the scope of the present invention.

As shown inFIG. 1, the LED lamp100of the present embodiment is an LED light bulb, and the LED lamp may be a light bulb with E27 plug, a light bulb with E26 plug, a light bulb with E14 plug, or light bulbs of other specifications. Specifically, the lamp housing110of the present embodiment includes a first cap112, a lampshade114, a second cap116and a conductive plug118. The lampshade114is connected to the first cap112, and the LED light source120is disposed in the lampshade114. The second cap116is connected to the first cap112, so that the first cap112is disposed between the lampshade114and the second cap116. In addition, the conductive plug118is connected to the second cap116, so that the second cap116is disposed between the conductive plug118and the first cap112. The conductive plug118of the present embodiment is an E27 plug, an E26 plug, an E14 plug, or plugs of other specifications, for example.

Generally, the first cap112and the second cap116are usually fabricated with insulation material (such as plastic) to ensure safety of users. However, the present invention does not limit that the first cap112and the second cap116have to be fabricated with the same insulation material. The first cap112and the second cap116may also be fabricated with conductive material according to different design requirements.

In an embodiment of the present invention, the material of the first cap112and the second cap116may be insulation material with doped zinc oxide. Since the insulation material with doped zinc oxide has function of Electro-Magnetic Interference shielding (EMI shielding), the first cap112and the second cap116with doped zinc oxide are capable of shielding the electromagnetic wave generated from the LED lamp100, such that harm resulted from the electromagnetic wave can be reduced. In addition, the first cap112and the second cap116may be fabricated by injection molding, and deformation of the first cap112and the second cap116made by the insulation material with doped zinc oxide can be effectively controlled after the first cap112and the second cap116are released from mold. Therefore, the yield rate of the first cap112and the second cap116can be increased.

As shown inFIG. 1, the LED light source120is an LED package fabricated by packaging process, and the package may be a SMD type package or other type of package. In the present embodiment, the LED light source120may be bonded with the heat sink130with solder material, so that the heat generated by the LED light source120can be effectively conducted to the heat sink130. Additionally, the present embodiment may also use thermal paste together with screw to perform the bonding between the LED light source120and the heat sink130.

In the present embodiment, the heat sink130may be fabricated with single material or a plurality of materials. In other words, the pedestal132and the heat dissipation fins134of the heat sink130may be fabricate with the same or different materials. Generally, the material of the heat sink130may be copper, aluminum, alloy, or other material with high thermal conductivity.

In the present embodiment, the control circuit140is a circuit board independent from the LED light source120. The circuit board may be a circuit board with single circuit layer or a circuit board with a plurality of circuit layers. In order to facilitate the air convection in the accommodating space110a, at least one through hole142may be fabricated on the circuit board. In an alternative embodiment of the present invention, the control circuit140may be a chip. When the control circuit140is a chip, the control circuit140may be integrated into the LED light source120to reduce the overall volume occupied by the LED lamp. Moreover, when the control circuit140is a chip, the control circuit140may also be integrated into the circuit board in the LED light source120.

The air inlets110band the air outlets110cformed on the lamp housing110are defined according to the convection direction of the air in the accommodating space110a. When the air in the accommodating space110aflows towards the second cap120from the first cap110, the openings on the first cap112are defined as the air inlets110b(as shown inFIG. 2AandFIG. 2B), and the openings on the second cap120are defined as the air outlets110c(as shown inFIG. 3AandFIG. 3B). On the contrary, when the air in the accommodating space110aflows towards the first cap110from the second cap120, the openings on the first cap112are defined as the air outlets110c(as shown inFIG. 2AandFIG. 2B), and the openings on the second cap120are defined as the air inlets110b(as shown inFIG. 3AandFIG. 3B).

With reference toFIG. 1,FIG. 2AandFIG. 2B, the openings on the first cap112(the air inlets110bor the air outlets110c) may be slot-shaped openings (slot-shaped air inlets or slot-shaped air outlets). In the present embodiment, the slot-shaped openings may be arranged in grating. Additionally, each of the slot-shaped openings is corresponding to one of the air convection channels136of the heat sink. Such design facilitates heat dissipation performance of the LED lamp100.

FIG. 2Ais a diagram of the first cap body having air inlets without barricade or air outlets without barricade, andFIG. 2Bis a diagram of the first cap body having air inlets with barricade or air outlets with barricade. With reference toFIG. 2AandFIG. 2B, if user can directly observe the situations in the first cap112through the air inlets110bor the air outlets110c, the air inlets110bor the air outlets110care so-called open type air inlets110bor open type air outlets110c(as shown inFIG. 2A); if user can't directly observe the inside of the first cap112through the air inlets110bor the air outlets110c, the air inlets110bor the air outlets110care so-called semi-open type air inlets110bor semi-open type air outlets110c(as shown inFIG. 2B).

FIG. 3Ais a diagram of the second cap body having air inlets without barricade or air outlets without barricade, andFIG. 3Bis a diagram of the second cap body having air inlets with barricade or air outlets with barricade With reference toFIG. 3AandFIG. 3B, similarly, if user can directly observe the inside of the second cap116through the air inlets110bor the air outlets110c, the air inlets110bor air outlets110care so-called open type air inlets110bor open type air outlets110c(as shown inFIG. 3A); if user can't directly observe the inside of the second cap116through the air inlets110bor the air outlets110c, the air inlets110bor air outlets110care so-called semi-open type air inlets110bor semi-open type air outlets110c(as shown inFIG. 3B).

The Second Embodiment

FIG. 4is a diagram of an LED lamp of the second embodiment of the present invention. With reference toFIG. 2, the LED lamp100′ of the present embodiment is similar to the LED lamp100illustrated in the first embodiment except that the LED lamp100′ of the present embodiment further includes a fan150disposed in the accommodating space110a, wherein the air from the environment is driven by the fan150to flow into the accommodating space110avia the air inlets110b, pass through the air convection channels136, and leave the accommodating space110avia the air outlets110cin sequence. As shown inFIG. 4, the fan150is disposed on the pedestal132, and the fan150is surrounded by the heat dissipation fins134. When the fan150is turned on, the air convection in the accommodating space110ais boosted, so that the LED lamp100′ can operate under a lower temperature. It is noted that, in the present embodiment, the fan150and the LED light source120are disposed on two opposite sides of the pedestal132, respectively.

The Third Embodiment

FIG. 5A˜FIG.5B are diagrams of relative locations of the fan, the control circuit, the heat sink and the LED light source of the third embodiment of the present invention. With reference toFIG. 5AandFIG. 5B, the present embodiment is similar to the second embodiment. In the present embodiment, the heat sink130has a first trench130aon one side to accommodate the LED light source120. The control circuit140(e.g. circuit board) is disposed on another side of the heat sink130. In addition, As shown inFIG. 5AandFIG. 5B, the control circuit140is disposed between the fan150and the heat sink130. In the present embodiment, the LED light source120may be bonded on the heat sink130with solder material, so that the heat generated by the LED light source120can be effectively conducted to the heat sink130. Additionally, the present embodiment may also use thermal paste together with screw to perform the bonding between the LED light source120and the heat sink130.

It is noted that the heat sink130used in the present embodiment may have an second trench130b(as shown inFIG. 5B) to accommodate the control circuit140. As shown inFIG. 5B, the second trench130bcan not only reduce the overall volume, but also allows the fan150to be closer to the heat sink130, so as to have a better heat dissipation performance.

As described above, the arrangement of the components of the LED lamp in the present invention may change in accordance with different design requirements. The above embodiment of the present invention is not used to limit the arrangement of components.

To sum up, the present invention uses the heat sink built in the LED lamp to dissipate heat generated therefrom, such that the operation temperature of LED lamp can be effectively maintained within an acceptable range. Therefore, the life span of LED lamp is prolonged.