KR101817157B1 - LED lamp - Google Patents

Abstract

The disclosed LED lamp includes a circuit board provided with an LED light emitting element, a heat radiating member for emitting heat of the LED light emitting element, and a lamp cover. The heat dissipating member has a mounting surface on which the circuit board is mounted, a core extending downward from the mounting surface, and an outer peripheral portion at least a portion extending to the lower side of the mounting surface.

Description

LED lamp

The present invention relates to an LED (light emitting diode) lamp.

A light emitting diode (LED) refers to a semiconductor device that can emit light of various colors by forming a light emitting source through a PN junction of a compound semiconductor (compound semiconductor). The LED has a long lifetime, can be reduced in size and weight, has a strong directivity of light, and can be driven at a low voltage. In addition, the LED is resistant to impact and vibration, does not require preheating time and complicated driving, can be packaged in various forms, and can be applied to various applications.

In recent years, attempts have been made to replace conventional lighting lamps such as incandescent lamps, fluorescent lamps, and halogen lamps with LEDs.

In order to replace traditional incandescent lamps such as incandescent lamps, halogen lamps, and fluorescent lamps with LEDs, an omni-directional lamp having a similar distribution to that of conventional lighting is required.

It is an object of the present invention to provide an LED lamp which is developed to satisfy the above-mentioned need and which has improved afterglow characteristics.

According to an aspect of the present invention, there is provided an LED lamp, comprising: a circuit board having an LED light emitting element; A first heat dissipating member made of metal and having a mounting surface on which the circuit board is mounted and a core extending downward from the mounting surface; And a second radiation member having a light transmitting property for emitting heat of the LED light emitting device to the outside.

And at least a part of the second heat radiation member may extend down to the mounting surface.

The first heat radiation member may be in contact with the second heat radiation member.

The first heat-radiating member may be located inside the second heat-radiating member and may be surrounded by the second heat-radiating member as a whole.

The first heat dissipating member may include at least one first heat dissipating unit extending to the outside of the core and the second heat dissipating member may include at least one second heat dissipating unit extending downward from the mount surface. The first heat radiation member may include a plurality of the first heat radiation parts arranged in a radial direction and the second heat radiation member may include a plurality of the second heat radiation parts disposed between the plurality of first heat radiation parts.

The second radiation member may be formed of a thermally conductive transparent ceramic material. The transparent ceramic material may include at least one selected from the group consisting of alumina, PLZT, CaF ₂ , Y ₂ O ₃ , YAG and polycrystalline AlON and MgAl ₂ O ₄ .

The LED lamp may further include a lamp cover coupled to the second heat radiation member. The lamp cover may diffuse and diffuse and reflect the light emitted from the LED light emitting device. A region other than a region where the LED light emitting device is mounted on the upper surface of the circuit board can be subjected to reflection processing. The lamp cover may be formed of at least one material selected from the group consisting of alumina, PLZT, CaF ₂ , Y ₂ O ₃ , YAG and polycrystalline AlON and MgAl ₂ O ₄ . The lamp cover may include a cover made of a light-transmitting material, and one or more thermally conductive layers directly contacting the heat-radiating member and formed on the outer periphery of the cover. The lamp cover may be formed of a material in which a thermally conductive filler is dispersed in a light-transmitting base material.

According to an aspect of the present invention, there is provided an LED lamp, comprising: a circuit board having an LED light emitting element; And a heat dissipation member for emitting heat of the LED light emitting device, the heat dissipation member including a mounting surface on which the circuit board is mounted, a core extending downward from the mounting surface, and a peripheral portion having translucency extending at least partially down to the mounting surface absence; And a lamp cover coupled to the heat dissipating member.

The heat dissipating member may be formed of a thermally conductive transparent ceramic material. The transparent ceramic material may include at least one selected from the group consisting of alumina, PLZT, CaF ₂ , Y ₂ O ₃ , YAG and polycrystalline AlON and MgAl ₂ O ₄ .

Wherein the heat dissipation member includes a first heat dissipation member made of metal and having the mounting surface and the core;

And a second heat dissipation member in contact with the first heat dissipation member and provided with the outer circumferential portion. The first heat-radiating member may be located inside the second heat-radiating member and may be surrounded by the second heat-radiating member as a whole. The first heat radiation member may include at least one first heat radiation portion radially extending to the outside of the core and the second heat radiation member may include at least one second heat radiation portion extending downward from the mounting surface . The second radiation member may be formed of at least one material selected from the group consisting of alumina, PLZT, CaF ₂ , Y ₂ O ₃ , YAG and polycrystalline AlON and MgAl ₂ O ₄ .

The lamp cover diffuses and diffuses and reflects light emitted from the LED light emitting device, and a region other than the area on which the LED light emitting device is mounted may be subjected to reflection treatment on the upper surface of the circuit board.

According to the above-described LED lamp of the present invention, an LED lamp having improved afterglow characteristics can be realized by adopting a heat dissipating member having at least a part extending down to a mounting surface of a circuit board provided with a light emitting device. Further, the heat radiation characteristic can be formed by utilizing the lamp cover as an effective heat radiation area.

1 is an exploded perspective view of an LED lamp according to an embodiment of the present invention;
FIG. 2 is a side view of an LED lamp according to an embodiment of the present invention shown in FIG. 1; FIG.
FIG. 3 is a cross-sectional view of an example of a coupling structure of a lamp cover and a second heat radiation member in an LED lamp according to an embodiment of the present invention shown in FIG. 1;
FIG. 4 is a graph showing the afterglow characteristics. FIG.
5 is a view showing an LED lamp in which light emitting elements are three-dimensionally arranged.
6 is an exploded perspective view showing a circuit board subjected to reflection processing;
7 is a side view of an LED lamp according to another embodiment of the present invention;
8 is a cross-sectional view taken along line XX ' Cross-section.
9 is a cross-sectional view showing an example of a lamp cover having a thermally conductive layer.
10 is a side view of an LED lamp according to another embodiment of the present invention;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements, and the size and thickness of each element may be exaggerated for clarity of explanation.

1 and 2 are an exploded perspective view and a side view, respectively, of an embodiment of an LED lamp according to the present invention. The LED lamp shown in Figs. 1 and 2 is an example of an incandescent lamp replacement LED lamp.

Referring to Figs. 1 and 2, the LED light emitting element 10 is mounted on the circuit board 20. Fig. The LED light emitting device 10 is a circuit in which an LED chip is packaged in the form of an LED package that is packaged by a preformed method using a lead frame, a mold frame, a fluorescent material, And can be mounted on the substrate 20. In addition, the LED light emitting device 10 may be mounted on the circuit board 20 by a wire bonding method in the form of an LED chip coated with a phosphor. In addition, the LED light emitting device 10 may be mounted on the circuit board 20 by a flip-chip bonding method in the form of an LED chip coated with a phosphor. The circuit board 20 may be a circuit board having a metal substrate or a metal core for improving heat dissipation characteristics.

The circuit board 20 on which the LED light emitting element 10 is mounted is mounted on the heat dissipating member 100. The heat dissipating member 100 of this embodiment includes a first heat dissipating member 30 provided with a mounting surface 31 on which the circuit board 20 is mounted and a second heat dissipating member 40 contacting with the first heat dissipating member 30. [ .

The power circuit section 50 electrically connects the socket section 70, which meets the specifications of, for example, incandescent lamps, to the circuit board 20. The power circuit unit 50 is provided with a driving circuit (not shown) for driving the LED light emitting element 10 using electric energy supplied through the socket unit 70. The insulating member 60 surrounds the power circuit portion 50 and insulates the heat radiating member 100 from the socket portion 60.

The lamp cover 80 is an open dome-shaped translucent cover inside and is coupled to the heat radiation member 100 to cover the light emitting portion including the LED light emitting element 10 and the circuit board 20. The lamp cover 80 has a bulb shape holding function, a function of protecting the LED light emitting element 10, and the like. Further, the lamp cover 80 may be a diffusion cover for diffusing reflection and diffusing light.

Referring to FIG. 3, the upper end of the second heat radiation member 40 may be provided with a coupling groove 44 to which the lamp cover 80 is coupled. 3, a spiral protrusion 82 is provided on the lower open edge 81 of the lamp cover 80, and the engaging groove 44 is formed in a shape complementary to the spiral protrusion 82 Shape. The method of joining the lamp cover 80 and the second heat radiation member 40 is not limited thereto, and various methods such as a snap-fit coupling method may be applied.

The heat generated in the process of driving the LED light emitting device 10 is transmitted to the first heat dissipation member 30 through the circuit board 20. The heat is conducted to the second heat radiation member 40 and is discharged to the atmosphere through the outer peripheral portion 41 of the second heat radiation member 40 exposed to the atmosphere.

In order to replace conventional lamps such as incandescent lamps, halogen lamps, and fluorescent lamps with LEDs, it is necessary to complement the downstream optical characteristics. 4, line A shows the light distribution characteristics in the LED package state. In the state of the LED package, the light emitted from the LED is almost directed forward, and it can be seen that there is almost no light directed toward the rear side of the line connecting 90 ° and -90 °. A method of adjusting the diffusion transmittance and the diffuse reflectance of the lamp cover 80 may be considered in order to realize the following optical characteristics.

The line B shows the result of simulating the light distribution characteristic when the diffuse reflectance of 50% and the diffuse transmittance of 50% are applied to the lamp cover 80. It can be confirmed that the light proceeds from the line B at an angle of 90 degrees or more. However, still more than 5% of the afterglow at an angle of 135 DEG or more is still present. In order to replace conventional lighting, the posterior light needs to be 5% or more at an angle of 135 ° or more.

In order to improve the afterglow characteristics, a method of three-dimensionally arranging a plurality of LED light emitting elements 10 by employing a single metal heat dissipating member 300 as shown in FIG. 5 may be considered. However, in this case, a plurality of circuit boards 20 are required, the path for supplying electricity to the circuit board 20 is complicated, and the shape of the heat radiation member 300 is also complicated. Therefore, the assembling process is complicated, and the mass production of the assembly may be deteriorated, and the process cost may increase. In order to realize the high efficiency and long life characteristics of the LED lamp, sufficient heat dissipation performance must be secured, and the higher the output, the more it is. 5, when the position of the upper mounting surface 301 is the same as the position of the mounting surface 31 shown in FIG. 2, the area of the outer circumferential portion 302 of the heat dissipating member 300 exposed to the outside is reduced, Can be lowered.

According to the LED lamp of this embodiment, the heat dissipating member 100 is divided into a first heat dissipating member 30 having a high thermal conductivity and a second heat dissipating member 40 having a light transmitting property. The circuit board 20 on which the LED light emitting element 10 is mounted is mounted directly on the first heat dissipating member 30. The first heat-radiating member 30 is formed of a metal material such as aluminum having a high thermal conductivity in order to discharge the heat generated from the LED light-emitting element 20 to the outside. The second radiation member 40 is formed of a translucent material having thermal conductivity. According to the embodiment of Figs. 1 and 2, the first heat-radiating member 30 can be disposed inside the second heat-radiating member 40. That is, the second heat-radiating member 40 may have a shape that entirely covers the first heat-radiating member 30. The second radiation member 40 is disposed outside the first radiation member 30 and is in contact with the first radiation member 30 to receive heat from the first radiation member 30 by conduction. The first radiating member 30 may include a core 32 extending downward from the mounting surface 31 and a plurality of radiating fins 33 extending outwardly from the core 32. [ The plurality of radiating fins (33) can be brought into contact with the second radiating member (40). Although not shown in the drawings, the first heat radiating member 30 and the second heat radiating member 40 may be coupled to each other by, for example, a fastening member such as a screw.

As the translucent material having thermal conductivity, a ceramic material can be utilized. For example, a molded product of alumina (Al ₂ O ₃ ) is a transparent material and has thermal conductivity. The thermal conductivity of AL ₂ O ₃ is about 33 W / m · K ^-1 at 25 ° C. The translucent material having thermal conductivity is not limited to alumina. For example, PLZT, which is used as an optical communication material using optoelectronic properties, and CaF ₂ , Y ₂ O ₃ , YAG and polycrystalline AlON, MgAl ₂ O ₄ having high cubic crystal, which are high quality transparent ceramic materials, Can be used as the material of the heat radiation member (40). AlON is produced by controlling the composition ratio of Al ₂ O ₃ and AlN and the amount of Y ₂ O _{3 ,} BN, CaO, MgO, etc. used as a sintering agent. Materials having high light transmittance and thermal conductivity depending on the composition ratio and amount . A AlON developed Surmet used is the composition ratio is _{AL 23 -1/3 x O 27 + x} N 5 -x (0.49 <x <2) thermal conductivity at 75 ℃ 9.7 W / m · K a ^- and ^1, MgAl ₂ O ₄ at 25 ° C 25 W / m · K ^-1 Transparency is about 76% of 650 nm wavelength light at 4 mm thickness.

According to such a configuration, the second radiation member 40 having a light transmitting property and a heat radiation property is extended to the lower side of the mounting surface 31. The light emitted from the LED light emitting element 10 may be emitted to the outside through the second heat dissipating member 40 directly as indicated by L 1 in FIG. The light emitted from the LED light emitting element 10 may be reflected from the inner surface of the lamp cover 80 and emitted to the outside through the second heat radiation member 40 as indicated by L2 in FIG. In addition, the light emitted from the LED light emitting element 10 may propagate through the interior of the lamp cover 80, as indicated by L3 in FIG. 2, and may be emitted to the outside through the second heat dissipating member 40.

As described above, by adopting the translucent second radiation member 40 extending down to the mounting surface 31, the following optical characteristics of the LED lamp can be realized. Referring to FIG. 4, the line C shows the result of simulating the light distribution characteristic when the second radiation member 40 is employed. It can be seen from this that the afterglow at 135 ° or more is increased compared with the case (line B) where the transparent second radiation member 40 is not used.

If the diffuse reflectance of the lamp cover 80 is increased, the post-exposure light can be further increased. That is, in FIG. 2, the amount of light traveling to the path of L2 can be increased. 6, the region 22 excluding the region 21 on which the LED light emitting device 10 is mounted is formed on the upper surface of the circuit board 20, as shown in FIG. 6, It can be a treated reflecting surface. The reflective surface can be implemented by, for example, attaching a reflective sheet to the area 22. The reflective surface can be realized by covering the region 22 with a metal material having a high reflectance by a method such as coating, plating, vapor deposition or the like and performing reflection processing. Thus, the light reflected by the diffused and reflected light on the circuit board 20 is reflected with a high efficiency, thereby making it possible to compensate the lowering of the light efficiency.

In the above-described embodiment, the second radiation member 40 surrounds the first radiation member 30 as a whole, but the scope of the present invention is not limited thereto. The second heat-radiating member 40 may be at least partially formed to extend under the mounting surface 31 of the first heat-radiating member 30. That is, a part of the first heat-radiating member 30 may be in contact with the outside air.

For example, referring to FIG. 8, which is a sectional view taken along the line X-X 'in FIGS. 7 and 7, the first heat radiation member 30a may include a plurality of first heat radiation units 36, 37, and 38. The plurality of first heat-radiating portions 36, 37, and 38 are arranged in the circumferential direction of the core 32 on which the mounting surface (31 in FIGS. 1 and 2) is formed. The second heat-radiating member 40a may include a plurality of second heat-radiating portions 46, 47, 48 divided in the circumferential direction. The plurality of second heat-radiating portions (46, 47, 48) extends under the mounting surface (31 in Figs. 1 and 2). The plurality of first heat dissipation units 36, 37, 38 and the plurality of second heat dissipation units 46, 47, 48 may be arranged alternately in the circumferential direction. The plurality of first and second heat dissipating units 36, 37, and 38 (46, 47, and 48) are at least partially in contact with each other for mutual thermal conduction.

The first radiation member 30a made of a metal generally has a higher thermal conductivity than the second radiation member 40a made of a translucent material. Therefore, the heat radiation characteristic can be improved by exposing the first heat radiation member 30a to the outside air.

7 and 8, a plurality of first heat dissipation units and a plurality of second heat dissipation units are provided. However, the scope of the present invention is not limited thereto. Although not shown in the drawing, it is also possible to provide a configuration in which one first heat-radiating portion and one second heat-radiating portion are provided.

LED lamps need to satisfy sufficient heat dissipation characteristics while maintaining the size and shape of traditional lighting. For this purpose, it is necessary to expand the heat radiation area in contact with the outside air. The lamp cover 80 which is in contact with the outside air in consideration of the fact that the lamp cover 80 is fastened to the first heat radiation member 30 or 30a or the second heat radiation member 40 or 40a, It is possible to consider the use of the outer surface of the heat sink as an effective heat radiation area. Generally, transparent materials such as glass, polycarbonate, and PMMA used as a material of the lamp cover 80 have a thermal conductivity of 0.3 to 3 W / m · K ^{- 1} is not suitable for heat dissipation material. The translucent material used as the material of the second heat radiation member 40 or 40a has a thermal conductivity ranging from several times to several tens of times higher than that of glass, polycarbonate (PC) resin or PMMA (polymethylmethacrylate) resin. Therefore, by employing the translucent material used for the second radiation member 40, 40a as the lamp cover 80, the lamp cover 80 can be utilized as an effective radiation area to improve the radiation performance.

The lamp cover 80 may be formed of a material in which a thermally conductive filler is dispersed in a light-transmitting base material. The translucent base material may be, for example, a glass, a polycarbonate (PC) resin, or a PMMA (polymethylmethacrylate) resin. The filler is preferably a transparent material, but not necessarily. For example, as the filler, particles such as carbon nanotube, graphene and the like may be employed. As the filler, particles of titanium oxide, zinc oxide, zirconium oxide, aluminum nitride, aluminum oxide and the like may be employed. The lamp cover 80 can be manufactured by a molding method such as injection molding or blow molding using a material in which at least one of the above-mentioned particles is dispersed in the light-transmitting base material. The thermally conductive filler may form a thermally conductive network within the translucent base material to improve the thermal conductivity of the lamp cover 80. Accordingly, the heat radiation performance of the LED lamp can be formed by utilizing the surface area of the lamp cover 80 as an effective heat radiation area.

9, the lamp cover 80 may include a transparent cover 84 and a thermally conductive layer 85 formed on the outer surface of the transparent cover 84. [ The translucent cover 84 may be formed of, for example, glass, polycarbonate (PC), or PMMA (polymethylmethacrylate) resin. As the material for forming the thermally conductive layer 85, for example, ITO (Indium Tin Oxide), SnO ₂ , ZnO, IZO (Indium Zinc Oxide), carbon nanotubes, and graphene may be employed. ITO, SnO ₂ , ZnO, and IZO are materials that are excellent in electrical conductivity and thermal conductivity enough to be used as electrode materials for flat panel display devices. Carbon nanotubes and graphene are also excellent thermally conductive materials. The thermally conductive layer 85 can be formed by coating the above materials on the surface of the transparent cover 84 by a method such as sputtering or vapor deposition. According to such a configuration, the heat radiation performance can be improved by utilizing the lamp cover 80 as an effective heat radiation area.

The heat dissipating member 100 has the first heat dissipating members 30 and 30a made of metal and the first heat dissipating members 30 and 30a having the mounting surface 31 on which the LED light emitting element 10 is mounted, Transmissive second radiation members 40 and 40a which are in contact with each other and extend at least partially below the mounting surface 31. However, the scope of the present invention is not limited thereto. As shown in Fig. 10, the heat dissipation member 100a may be a structure formed entirely of the above-mentioned light-transmitting and heat-conductive material and extending downward from the mount surface 31. [ That is, the heat radiating member 100a has a mounting surface 31 on which the circuit board 10 is mounted, a core 32 extending downward from the mounting surface 31, and an outer peripheral portion 101 exposed to the outside air And a part of the outer circumferential portion 101 may extend to the lower side of the mounting surface 31. The outer peripheral portion 101 and the core 32 may be connected to each other by the radiating fin 33.

The above-described embodiments are merely illustrative, and various modifications and equivalent other embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of protection of the present invention should be determined by the technical idea of the invention described in the following claims.

10 ... LED light emitting element 20 ...... circuit board
30, 30a ... First heat radiating member 31 ... Mounting surface
32 ... core 33 ... heat sink fin
36, 37, 38 ... first heat-radiating portions 40, 40a ... second heat-
44 ... coupling grooves 46, 47, 48 ... second heat-
50 ... power circuit portion 60 ... insulating member
70 ... Socket section 80 ... Lamp cover
85 ... thermally conductive layer 100, 100a ... heat-

Claims (22)

A circuit board provided with an LED light emitting element;
A first heat dissipating member made of metal and having a mounting surface on which the circuit board is mounted and a core extending downward from the mounting surface;
And a second heat dissipating member having a light transmitting property for emitting heat of the LED light emitting device to the outside,
Wherein the first heat radiation member has at least one first heat radiation portion extending to the outside of the core,
The second radiation member includes at least one second radiation member extending downward from the mounting surface,
And the first heat-radiating portion and the second heat-radiating portion are exposed to the outside. delete The method according to claim 1,
And the first heat radiation member is in contact with the second heat radiation member. delete delete The method according to claim 1,
Wherein the first heat radiation member has a plurality of the first heat radiation parts arranged in a radial direction,
And the second heat radiation member includes a plurality of the second heat radiation parts disposed between the plurality of first heat radiation parts. delete delete The method according to any one of claims 1, 3, and 6,
And a lamp cover coupled to the second heat radiation member. 10. The method of claim 9,
The lamp cover diffuses and diffuses and reflects light emitted from the LED light emitting device. 11. The method of claim 10,
Wherein an area of the upper surface of the circuit board other than a region on which the LED light emitting device is mounted is subjected to reflection processing. delete 10. The method of claim 9,
Wherein the lamp cover includes a cover made of a translucent material and one or more thermally conductive layers that are in contact with the second heat radiation member and formed on the outer periphery of the cover. delete delete delete delete delete delete delete delete delete

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