JP3965929B2 - LED lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an LED lighting device, and more particularly to an LED lighting device for a traffic light.
[0002]
[Prior art]
In recent years, light emitting diodes capable of emitting blue light have been developed, and since the luminance of the light emitting diodes has improved, signal lights and lighting equipment using the light emitting diodes have been manufactured.
FIG. 9 is a cross-sectional view showing a configuration of a conventional LED lighting device used as, for example, a signal lamp. In this conventional LED lighting device (hereinafter referred to as a first conventional example), a plurality of light emitting diodes 5 are arranged. The substrate 4 is attached to the bottom surface of the resin case 103 via the metal plate 101 and is further hermetically sealed by providing the transparent cover 7 on the front surface of the resin case 103.
In the conventional LED lighting device configured as described above, light output from the light emitting diode 5 is output through the transparent cover 7, and heat generated by the light emitting diode is transmitted to the bottom of the resin cover 103 by the metal plate 101. Further, heat is radiated from the outer surface of the bottom of the resin cover 103.
[0003]
Further, the following structure has been proposed as a structure with improved heat dissipation characteristics.
The LED illumination device of FIG. 10 is a conventional LED illumination device (hereinafter referred to as a second conventional example) with improved heat dissipation characteristics compared to the conventional example of FIG. 9, and as shown in FIG. The metal plate 101 a is provided not only on the bottom of the resin case 103 but along the entire inner surface of the resin case 103.
In the LED illuminating device of FIG. 10 configured as described above, heat can be released from the entire outer surface of the resin case 103, so that the heat dissipation characteristics can be improved compared to the conventional example of FIG.
In addition to the structure of FIG. 10, a structure (hereinafter, referred to as “heat dissipation characteristics”) is provided by providing a heat sink on the bottom surface of the resin case so that the back surface of the metal plate directly touches the outside air, and a heat sink on the surface touching the outside air. The third conventional example) has also been proposed.
[0004]
[Problems to be solved by the invention]
However, the LED lighting device of the first conventional example in FIG. 9 has a problem that it is not suitable for brighter illumination that requires a large current.
In addition, the LED lighting device of the second conventional example has good heat dissipation characteristics, but there is a problem that it cannot be lightened because the metal plate becomes large.
Further, the LED lighting device of the third conventional example has a problem that the sealing performance may be deteriorated because it is necessary to attach the heat radiation surface of the metal plate to the resin cover so as to be in contact with the outside air.
[0005]
Accordingly, an object of the present invention is to provide an LED lighting device that can maintain high sealing characteristics and has good heat dissipation characteristics.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an LED lighting apparatus according to the present invention includes a substrate on which a plurality of light emitting diodes are arranged on one surface, and a resin case having a bottom portion to which the substrate is attached. An LED lighting device that is attached to the bottom via a heat-dissipating fixing plate,
A convex portion is formed on the surface of the heat radiation fixing plate facing the surface on which the substrate is mounted so as to increase the contact area with the bottom of the resin case.
Since the LED lighting device configured as described above can increase the contact area between the heat radiation fixing plate and the bottom of the resin case, the heat generated by the light emitting diode is effectively applied to the resin case via the heat radiation fixing plate. Therefore, heat can be efficiently radiated from the surface of the resin case, and the heat radiation characteristics can be improved.
[0007]
In addition, the LED lighting device according to the present invention is configured to transmit heat generated by the light emitting diodes to the heat radiation fixing plate along one surface of the substrate, except for the light emitting portions of the light emitting diodes. It is preferable to further include a heat dissipation cover that covers one surface of the substrate, and the heat dissipation cover is fixed to the heat dissipation fixing plate so as to contact the surface around the substrate.
[0008]
In the LED lighting device according to the present invention, it is preferable that the heat dissipation fixing plate and the resin case are integrally formed.
[0009]
In the LED lighting device according to the present invention, in order to efficiently transfer heat to the resin case, the protrusions are preferably cooling fins that are formed long in one direction and parallel to each other.
[0010]
In the LED lighting device according to the present invention, in order to release heat more effectively from the surface of the resin case, the bottom of the resin case is formed with irregularities corresponding to the convex portions of the heat radiation fixing plate. More preferably.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments according to the present invention will be described below.
As shown in FIG. 1, the LED lighting device according to the present invention is provided with a substrate 4 on which a plurality of light emitting diodes 5 are arranged on the bottom of a resin case 3 via a heat radiation fixing plate 1, and on the front surface of the resin case 3. An LED lighting device used for a signal lamp configured by attaching a translucent cover 7 and has the following characteristics.
[0012]
(1) In the LED lighting device of the present embodiment, the heat radiation fixing plate 1 is made of, for example, metal, a plurality of heat radiation fins 1a are formed in parallel on the lower surface, and the fins 1a are resin on the bottom of the resin case 3. It is provided so that it may be embedded in.
In addition, the lower surface of the board | substrate 4 is provided in contact with the upper surface of the thermal radiation fixing plate 1. FIG.
(2) Further, a heat radiating cover 2 made of metal, for example, is provided so as to cover the upper surface of the substrate 4 except for the light emitting portion of the light emitting diode 5, and the heat radiating cover 2 is connected to the heat radiating fixing plate 1 around the substrate 4. It is fixed so that it contacts the surface.
The heat radiating cover 2 has a function of transmitting heat generated in the light emitting diode 5 to the heat radiating fixing plate 1, whereby heat generated in the light emitting die auto 5 is connected to the first path through the heat radiating cover 2 and the substrate. Therefore, the heat generated in the light emitting diode 5 can be more effectively transmitted to the heat radiation fixing plate 1.
In the present specification, the term “upper surface” or “lower surface” refers to a surface located on the light emitting side (front side) of the LED lighting device.
[0013]
With reference to FIG. 4, the LED lighting device of the present embodiment will be described in detail.
FIG. 4 shows an example in which a surface mount type light emitting diode 50 is used.
In the LED lighting device of the present embodiment, the heat radiation fixing plate 1 having the fins 1a formed on the lower surface is fixed to the bottom of the resin case 3 by integral molding.
Here, as shown in FIG. 3, the fin 1 a has a fin-like shape that is sufficiently long in one direction, and is formed on the lower surface of the heat radiation fixing plate 1 in parallel with each other.
Further, in the present embodiment, the heat radiation fixing plate 1 is integrally formed with the resin for molding the resin case so that the fins 1a are embedded in the bottom of the resin case 3 and cover the entire lower surface of the heat radiation fixing plate 1. .
[0014]
The substrate 4 on which the light emitting diodes 50 are arranged in a predetermined arrangement on the upper surface is fixed so that the lower surface of the substrate 4 is in contact with the upper surface of the heat radiation fixing plate 1.
Further, an insulating sheet 6 having through openings 6 a corresponding to the respective light emitting diodes 50 is provided on the upper surface of the substrate 4 so as to cover the upper surface of the substrate 4.
On the insulating sheet 6, the heat dissipation cover 2 in which the through openings 11 a are formed corresponding to the light emitting diodes 50 is provided so as to cover the substrate 4 with the insulating sheet 6 interposed therebetween.
Here, when the heat radiating cover 2 covers the substrate 4, the heat radiating cover 2 is bent along the side surface of the substrate 4 so as to come into surface contact with the heat radiating fixing plate 1, and heat is radiated at the bent brim portion. It is fixed to the fixed plate 1.
[0015]
In the LED lighting device according to the embodiment configured as described above, the heat generated in each light emitting diode 50 as shown by the arrows in the cross-sectional view of FIG. Simultaneously with the first path, the heat generated in each light emitting diode 50 is transmitted laterally through the heat dissipation cover 2 to be transmitted to the plate 1 (the first path), and the heat radiation fixing plate around the substrate 4 1 is transmitted to the heat radiating fixing plate 1 from the portion of the collar that is in surface contact with 1 (second path). In this way, the heat transmitted to the heat radiation fixing plate 1 by the first path and the second path is transmitted from the lower surface of the heat radiation fixing plate 1 and the fins 1a to the resin at the bottom of the resin case 3 so that the resin Heat is radiated from the surface.
[0016]
As described above, in the LED lighting device according to the present embodiment, the heat generated in the light emitting diode 5 can be transmitted to the heat radiation fixing plate 1 through the two paths of the first path and the second path. The heat generated by the die auto 5 can be effectively transmitted to the heat radiation fixing plate 1.
Further, since the heat dissipating fixing plate 1 has a plurality of fins 1a formed on the lower surface thereof, the contact area between the lower surface of the heat dissipating fixing plate 1 and the bottom surface of the resin case 3 can be increased, and heat can be efficiently transferred to the resin case 3. it can.
As described above, in the LED lighting device of the present embodiment, the heat generated in the light emitting diode 50 is efficiently transmitted to the resin case 3 and can be discharged from the outer surface of the resin case 3, so that it is compared with the conventional example. Good heat dissipation characteristics.
[0017]
Furthermore, in the LED lighting device of the present embodiment, the heat radiation fixing plate 1 is integrally formed with the resin case molding resin so that the fins 1a are embedded in the bottom of the resin case 3, so that the heat radiation fixing plate is caused by the anchor effect. 1 can be firmly fixed to the bottom surface of the resin case 3.
Further, in the LED lighting device of the present embodiment, the heat radiation fixing plate 1 and the heat radiation cover 2 are fixed so as to sandwich the substrate on which the light emitting diode is mounted, so that displacement and dropout of the substrate due to vibration can be prevented, Vibration resistance can be improved.
Thus, for example, high reliability can be obtained even when used in an application such as a signal lamp that is always installed in a place exposed to vibration.
[0018]
Further, in the LED lighting device of the present embodiment, even when the substrate on which the light emitting diode is mounted includes a power supply circuit by using, for example, metal having a shielding effect as the heat radiation fixing plate 1 and the heat radiation cover 2, respectively. The noise generated by the power supply circuit can be blocked, and malfunction of other electronic devices due to the noise of the LED lighting device can be prevented. Thereby, it can apply to various uses, such as various lighting equipment in an office, and the reading light of an aircraft.
Further, in the LED lighting device of the present embodiment, since it is integrally formed with the resin for molding the resin case so as to cover the entire lower surface of the heat-dissipating fixing plate 1, the airtightness can be improved and used for outdoor use. Even long life is obtained.
[0019]
In the example shown in FIG. 4 described above, the LED lighting device configured by using the surface-mount type light emitting diode 50 has been described. However, even if the light emitting diode 5 having the pin lead is used, the LED lighting device can be configured similarly. The following effects can be obtained.
That is, in the LED lighting device configured using the light-emitting diode 5, as shown in FIG. 6, instead of the insulating sheet 6 formed on the upper surface of the substrate 4 in FIG. Except for the provision of 60, the configuration is the same as the case of using the surface-mount type light emitting diode 50.
Here, FIG. 6 is an enlarged cross-sectional view of a part of the LED illumination device shown in FIG. 1 (configured using the light-emitting diode 5 having pin leads).
[0020]
Hereinafter, modifications according to the present invention will be described.
Modification 1
FIG. 7 is a partial cross-sectional view of the LED lighting device of Modification 1 according to the present invention.
The LED lighting device according to the first modification is characterized in that recesses 3 a are formed correspondingly between adjacent fins 1 a at the bottom of the resin case 3, whereby the outer surface of the bottom of the resin case 3 is formed. Can increase the surface area and efficiently release heat from the outer surface.
That is, in the first modification, the bottom of the resin case 3 (outer surface) is formed with irregularities so as to correspond to the irregularities of the heat-dissipating fixing plate 1, and the resin case 3, which is the main part for releasing heat to the outside air. The surface area of the outer surface of the bottom is increased to further improve the heat release effect.
[0021]
Modification 2
FIG. 8 is a partial cross-sectional view of the LED lighting device of Modification 2 according to the present invention.
The LED illuminating device of Modification 2 is configured in the same manner as in FIG. 1 except that the LED illuminating device in FIG. 1 is configured using a heat radiating fixing plate 10 instead of the heat radiating fixing plate 1.
In FIG. 8, the resin case has a shape different from that of the resin case of FIG.
That is, the heat radiation fixing plate 10 used in the LED lighting device according to the modified example 2 is provided along the bottom and inner peripheral side surfaces of the resin case 30, and the fin 10 b is formed on the entire portion in contact with the resin case 30.
The LED lighting device of Modification 2 configured as described above can transmit heat generated by the light emitting diode 5 to the bottom surface of the resin case 30 and the outer peripheral side surface of the resin case 30 via the heat radiation fixing plate 10. The heat can be released from the entire outer surface.
Thereby, compared with the LED lighting device of embodiment, heat can be emitted more efficiently.
[0022]
Modification 3
In the LED lighting device according to the embodiment, the insulating sheet 6 or the insulating sheet 60 is used. However, instead of the insulating sheet, grease or the like excellent in insulating properties and thermal conductivity may be used.
[0023]
As described above, the LED lighting device according to the embodiment and the modification includes (1) providing the heat dissipation cover 2 to transmit heat generated in each light emitting diode to the heat dissipation fixing plate 1 mainly through two heat transfer paths, (2) The structure of increasing the contact area between the heat radiation fixing plate 1 and the resin case, and (3) increasing the area of the outer surface of the portion where the heat transferred in the resin case 3 is large (related to Modification 1). As a result, the heat dissipation characteristics are improved as a whole of the LED lighting device.
As mentioned above, although the favorable heat dissipation characteristic resulting from the characteristic structure in this invention was mainly demonstrated, in order to exhibit the favorable heat dissipation characteristic resulting from these characteristic structures more effectively, with respect to each component It is preferable to apply the following materials.
[0024]
That is, in the LED lighting device of the present invention, it is preferable to use, for example, a metal with good thermal conductivity such as aluminum or copper or a ceramic with good thermal conductivity as the heat radiation fixing plate 1. Or it can produce by cutting. Moreover, when using ceramic, it can produce by baking after shape | molding to a defined shape.
Moreover, in order to improve the thermal radiation amount of the heat-dissipating fixing plate 1, the surface may be painted using black alumite treatment or black paint.
[0025]
Further, as the resin for the resin case 3, it is preferable to use a resin having relatively high thermal conductivity such as ABS resin or polycarbonate. In order to improve thermal conductivity, alumina, aluminum nitride ( More preferably, AlN) or beryllium oxide (BeO) is added.
[0026]
【The invention's effect】
As described above in detail, in the LED lighting device according to the present invention, the substrate on which the plurality of light emitting diodes are arranged on one surface is formed with a convex portion so as to increase the contact area with the bottom of the resin case. Since it is attached via the heat radiation fixing plate, the heat generated by the light emitting diode can be effectively transferred to the resin case via the heat radiation fixing plate, and efficiently radiated from the surface of the resin case, Good heat dissipation characteristics. Thereby, according to the LED lighting device according to the present invention, since the heat radiation characteristics can be improved without directly exposing the heat radiation fixing plate to the outside air, it is possible to maintain the high sealing characteristics and the LED radiation devices with good heat radiation characteristics. Can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of an LED illumination device (an example using a light emitting diode having a pin lead) according to an embodiment of the present invention.
2 is a plan view of a bottom surface of a resin case 3 to which a substrate 4 is attached as viewed from the front in the LED lighting device of FIG. 1;
FIG. 3 is a plan view of the lower surface of the heat radiation fixing plate 1 according to the embodiment.
FIG. 4 is an exploded perspective view of the LED lighting device according to the embodiment (an example using a surface-mount type light emitting diode).
FIG. 5 is a cross-sectional view of the LED lighting device according to the embodiment (an example using a surface-mount type light emitting diode).
6 is a partial cross-sectional view of the LED lighting device of FIG. 1;
FIG. 7 is a partial cross-sectional view of an LED lighting device according to Modification 1 of the present invention.
FIG. 8 is a partial cross-sectional view of an LED illumination device of a second modification according to the present invention.
FIG. 9 is a cross-sectional view of a first conventional LED lighting device.
FIG. 10 is a cross-sectional view of a second conventional LED lighting device.
[Explanation of symbols]
1, 10 ... heat radiation fixing plate,
1a, 10b ... fins for heat dissipation,
2 ... Heat dissipation cover,
3, 30 ... resin case,
4 ... substrate
5, 50 ... Light emitting diode,
6, 60 ... insulating sheet,
7 ... Translucent cover.

Claims (5)

An LED lighting device comprising a substrate on which a plurality of light emitting diodes are arranged on one surface and a resin case having a bottom portion to which the substrate is attached, the substrate being attached to the bottom portion via a heat radiation fixing plate. And
An LED lighting device, wherein a convex portion is formed on a surface of the heat radiation fixing plate facing a surface on which the substrate is attached so as to increase a contact area with a bottom portion of the resin case. Except for the light emitting portion of each of the light emitting diodes, it further includes a heat radiating cover that covers one surface of the substrate, and the heat radiating cover is fixed so as to be in contact with the heat radiating fixing plate around the substrate. The LED lighting device according to claim 1. The LED lighting device according to claim 1, wherein the heat radiation fixing plate and the resin case are integrally formed. The LED illumination device according to any one of claims 1 to 3, wherein the protrusions are cooling fins that are long in one direction and formed in parallel to each other. The LED lighting device according to any one of claims 1 to 3, wherein the bottom of the resin case is provided with irregularities corresponding to the convex portions of the heat radiation fixing plate.

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