JP2011040622A - Led package board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the heat radiation property of an LED package board using a lead frame in a p pole and an n pole without providing any LED package or heat sink. <P>SOLUTION: A portion of the end of a lead frame which is high in heat conductivity is structured so as to be extended to a position separated from an LED element so that it is possible to improve the effects of heat radiation from the section. Also, the extended section is projected to the outside of an LED illuminating device casing so that it is possible to increase the effects. Thus, it is possible to efficiently perform the heat radiation of heat generated from the LED element in a LED package board. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an LED package substrate.

LED light-emitting technology is progressing year by year, and the increase in voltage and the amount of light emission associated therewith are increasing at an accelerated pace. However, a countermeasure for heat generated by light emission has not been caught up, and a small LED device still has a problem with heat dissipation.

If the heat dissipation is not sufficient, there is an adverse effect that the light emitting efficiency of the LED element is lowered or the resin sealing member is deteriorated, which becomes a factor of greatly shortening the life.

The structure of the LED package currently most used is a system in which a circuit is printed by gold plating or the like on a substrate such as AlN (aluminum nitride) and the LED element is embedded in a predetermined portion provided on the circuit. In this method, an expensive sintered body of AlN is used and printing such as gold plating is required, so that it cannot be manufactured at a low cost.

Therefore, as shown in Patent Document 1, the present applicant uses a flip chip mounting method that is advantageous for heat dissipation using ceramics having excellent strength and weather resistance as a member to be used as copper as a basic frame. An improved LED package substrate was invented.

WO2009 / 051178 International Publication Patent This document describes a method of performing heat dissipation using a lead frame (basic frame), and when heat generation is large, a heat sink is used in the direction of the chip and the back side of the basic frame. A method is described.

As described above, when heat generation is large, using a heat sink as a countermeasure (refer to Cited Document 1 FIGS. 4 and 5) increases the cost of the package. Further, since the weight increases, it is necessary to slightly strengthen the overall structure of the LED package itself that supports it. This also affects the cost.

Heat dissipation is improved by using a flip chip mounting method that is advantageous for heat dissipation using ceramics with excellent strength and weather resistance as a member used to separate the p-pole and n-pole using copper or the like as a basic frame. An object of the present invention is to obtain a heat dissipation characteristic equivalent to or higher than that of an LED package substrate at low cost without using a heat sink even when heat generation is large in the LED package substrate.

  The present invention according to claim 1 is a substrate of an LED package having no heat sink on which an LED element is mounted, and an n electrode connected to the n pole of the LED element and a p connected to the p pole of the LED element. In an LED package in which a part or all of the narrowest part of the electrode is filled with ceramics, and the n electrode and the p electrode are formed by a lead frame, at least a part of the lead frame on which the lead frame element is mounted On the other hand, the LED package substrate extends toward a lower direction at a temperature different from the direction of the LED elements by at least 10 mm or more. The 10 mm base point is from the end of the reflector.

  First, as a feature of the present invention, the LED package does not have a heat sink which is disadvantageous in terms of cost. The portions corresponding to the p-pole and n-pole of the LED element are formed by a lead frame. In addition, the structure around the element is basically filled with insulating ceramics.

  In this structure, for the p-pole or n-pole lead frame, the shape of the part on which the element is mounted and the part away from the part can be freely set. Therefore, in the present invention, the end portion side of the lead frame is extended, and the length thereof is set to a minimum of 10 mm from the end portion of the reflector. Since this further extended portion is continuous in a state where the thermal conductivity from the LED element is kept high, it can be used as a portion for heat dissipation. The reason why the minimum value is 10 mm is that the heat dissipation effect is not sufficient below this value. Although there is no particular upper limit on the length, it goes without saying that the range is not in contact with or in close proximity so as to affect other parts. Further, the portion is not limited to a straight line, but may have various shapes such as a spiral shape or a meander-shaped cross section. The number of portions extending from the lead frame is not limited to one, and a plurality of portions can be provided.

Further, the portion extended by 10 mm or more needs to be extended in a direction different from the LED element. Since the said part aims at heat dissipation, it is necessary to extend in the direction where temperature is lower. Therefore, it is necessary to extend in a direction different from that of the LED that generates heat, specifically, a space corresponding to the back surface of the light emitting surface of the LED.

The present invention according to claim 2 is the LED package substrate according to claim 1, wherein the lead frame is made of copper or a copper compound having a thermal conductivity of 300 W / m · K or more. In the case of the product of the present invention that does not use a heat sink, the heat conduction of the lead frame greatly affects its heat dissipation. If the thermal conductivity of the lead frame is less than 300 W / m · K, it is difficult to sufficiently release the high heat generated from the LED element. The higher the thermal conductivity, the better.

  A third aspect of the present invention is the LED package substrate according to the first or second aspect, wherein an extended portion of the lead frame is fixed to an LED illuminator housing.

Since the extended portion is elastic, it may be in contact with other parts and adversely affected. For this purpose, fixing with an insulating part with high thermal conductivity such as an aluminum nitride washer provided inside the housing of the LED illuminator also improves heat dissipation, and p-pole and n-pole insulation can be taken from there. it can.

  According to the fourth aspect of the present invention, a part of the extended portion of the lead frame protrudes outside the housing of the LED lighting device or is fixed in a state of being in contact with a heat sink attached to the outside of the housing. The LED package substrate according to claim 1, wherein the LED package substrate is characterized in that

  The heat sink shown in the cited document 1 and the like releases heat to the inside of the LED illuminator, whereas the present invention releases heat to the outside. If the heat is released from the inside, the temperature of the whole inside may rise. Therefore, the temperature inside the LED illuminator can be kept low by mainly performing this to the outside.

As a method for releasing heat to the outside, firstly, the extended portion of the lead frame protruding to the outside is preferably provided with a length of 3 mm or more, and the other is connected to a heat sink provided outside. That is.

  The present invention achieves at least one of the following effects.

  Since a heat sink is not used for the LED package substrate, the cost can be reduced. Moreover, the weight of the package can be reduced.

  In addition, since the extended portion of the lead frame can be extended to the outside of the LED housing or to the heat sink provided outside the housing, unlike the case where the heat sink is provided in the vicinity of the LED element as in the cited reference 1, the LED Heat can be released outside the illuminator.

Also, insulation can be taken at the portion of the lead frame where heat is dissipated.

The invention according to claim 1 of the present invention will be described with reference to FIG. 1 and FIG. 7 showing the prior art (cited document 1) (a diagram based on FIG. 4B of the cited document).

As shown in FIG. 7, the structure of the cited document has the heat sinks shown in 108b and 108c directly under the lead frames 101 and 102 having the p-pole and the n-pole. Using this heat sink, the heat of the LED element mounted on the upper surface toward 101 and 102,

LED element (not shown, part A)-lead frame (101, 102)-heat sink (108b, 108c)-air below it

Dissipate heat through the path.

The lead frames (108b and 108c) are illustrated so as to cover the side surfaces with the reflector 107. However, it is not necessary to cover all of the side surfaces, and the lead frames (108b and 108c) extend to the outside of the reflector 107 as shown by 200 in FIG. be able to.

The description of FIG. 1 of the present invention will now be given.
The LED package substrate of the present invention is obtained by further extending a lead frame part 200 additionally shown in FIG. 4 by 10 mm or more in a direction different from the element as shown (201). This LED package substrate is not provided with a heat sink. The extending direction is different from the direction in which the element is present (in this case, the lower side of the drawing). The extended portion generates heat from the device, extending as part of the lead frame to a place where the temperature is relatively lower than the periphery of the device, and radiates heat.

According to a second aspect of the present invention, the lead frame is made of copper and a copper alloy, and is made of a high thermal conductivity member having a thermal conductivity of 300 W / m · K or more. In the present invention, since the point is how to conduct heat from a portion close to the element having high heat, naturally, it is better that the heat conduction is high.

  The invention according to claim 3 will be described with reference to FIG.

  The extended portion 201 of the lead frame obtained in the description of claim 1 is fixed by a receiver 210 whose tip is an insulating member and is fixed to the casing. If not fixed, especially copper and copper alloys as shown in claim 2 are soft and elastically deformed, so impact and thermal adverse effects will be caused by approaching and contacting other parts. There is. Therefore, this problem can be solved by fixing with the receptacle 210.

The reason why the member of the receiver 210 is an insulating member is that it can also serve to insulate the p-pole and the n-pole from there. Furthermore, further heat radiation can be expected by making the receiver 210 made of, for example, aluminum nitride having high thermal conductivity.

  The present invention according to claim 4 will be described with reference to FIG. In this figure, a general structure of an LED illuminator having a hole in a part of a housing is shown for explanation. The LED package substrate is 300, the lead frame extending from the LED package substrate is 201, and the hole provided in the LED lighting device is 301. Note that there may be a heat sink 302 provided outside the housing of the LED illuminator as shown in FIG.

  FIG. 5A shows a schematic diagram in which a part of the extended portion of the lead frame protrudes outside the LED package. As described above, since heat is not accumulated inside the LED illuminator housing, the internal temperature can be kept low.

  FIG. 5B shows an example in which the leading end of the lead frame is connected to a heat sink 302 provided outside the housing of the LED illuminator.

By using these methods, it is difficult for heat to accumulate in the housing of the LED illuminator, and because the heat dissipation part and the lead frame on which the LED is mounted are connected by a high thermal conductive material, The effect is higher.

Hereinafter, the present invention will be described in more detail by way of examples.

Example 1
As Example 1, as shown in FIG. 2A, the n-electrode and the p-electrode are formed by a lead frame without a heat sink on which the LED element is mounted, and a part of the lead frame is an LED element. An LED package substrate having a portion 200 extending in a direction opposite to a different LED element and having a length of 50 mm was manufactured.

In Example 2, the other parts of Sample 1 were the same, and the extended part 200 of the lead frame was 202 processed into a meander shape as shown in FIG. The total length of this extended portion is 200 mm.

Furthermore, as Example 3, the other part was the same as that of Sample 1, and the part 200 where the lead frame was extended was closely fixed to the washer 210 which is an insulating receiver made of aluminum nitride (see FIG. 3). .

Furthermore, as Example 4, a sample in which an extended portion 201 of a lead frame as shown in FIG. 5A protrudes 50 mm inside the LED illuminator housing and 10 mm outside through a hole 301 communicating with the outside. Using.

Finally, as Example 5, as shown in FIG. 5 (b), the extended portion 201 of the lead frame is the same as in Example 4, and the heat sink provided outside the LED illuminator casing at the end thereof. A sample connected to 302 was used.

  As Comparative Example 1, a sample using the heat sink shown in the cited document 1 as shown in FIG. 7 was prepared.

Further, as Comparative Example 2, as shown in FIG. 8, the same part as Comparative Example 1 was used, and a sample from which only the heat sinks 108b and 108c were removed was used.

  10 LED elements mounted using the samples of these Examples and Comparative Examples were energized with a voltage of 5 V DC and a current of 0.3 A, and the surface temperature of the elements was measured continuously from the time of lighting by thermography. .

In addition, in order to measure temperature correctly, the sealing material which normally seals an LED element is not used.

As a result, the result shown in FIG. 6 was obtained.

  Comparative Example 1 is a conventional technique and is data of a sample using a heat sink. The temperature is stable at about 50 ° C.

  Compared to this, the temperature at which Example 1 was stabilized was slightly higher than that of Comparative Example 1, but it was a practically sufficient value (about 60 ° C.).

  Further, Examples 2 and 3 remained at a slightly lower temperature than Comparative Example 1, and the heat dissipation effect due to the extended portion of the lead frame was confirmed.

  In addition, Comparative Example 2 is a comparative example in which the LED package does not have a heat sink or an extended portion of the lead frame, but the temperature is extremely high compared to other examples and comparative examples, and is in a range where it cannot be used. .

In addition, it was found from comparison between Examples 1 and 2 that the portion 200 where the lead frame was extended had a longer total extension, and the effect was enhanced as the area increased.

  Furthermore, it was found from the comparison between Example 1 and Example 3 that the heat radiation is further increased when the receiver 210 is provided. In the embodiment 3, since the extended portion 200 of the lead frame is fixed, it is advantageous in terms of impact and movement from the outside, and insulation can be reliably obtained.

In the samples of Examples 4 and 5, since the tip of heat dissipation was outside the housing, the temperature was clearly kept lower than the sample of Comparative Example 1, and superiority was observed. In particular, Sample 5 was able to obtain the lowest temperature in this experiment.

It is the schematic diagram which extended a part of lead frame of the present invention unexpectedly in the direction with an element. (A) It is the schematic diagram which extended a part of lead frame of this invention unexpectedly in the direction with an element. (B) It is the schematic diagram which made the extended part of a lead frame meander shape. FIG. 4 is a schematic view in which a part of the lead frame of the present invention is fixed by a receiver fixed to a housing. It is a schematic diagram of the LED package board | substrate of a prior art. Schematic diagram of a part of the lead frame that has a hole leading to the outside in the case of the LED lighting device (a) a part of the lead frame (b) fixed to a heat sink outside the case It is. It is a temperature change of an LED element at the time of using the Example and comparative example of this invention. It is a schematic diagram of the LED package of a prior art. It is the schematic diagram which removed the heat sink from the LED package of a prior art.

A LED element mounting portion 101, 102 p-pole and n-pole by lead frame 103 ceramic 107 reflector 108 (a), (b) heat sink 150 housing 151 of LED illuminator printed circuit board 152 reflector 153 lens 154 electronic component 155 printed circuit board Fixed part 200 of the case Part 201 and 202 of the lead frame 210 Extended part of the lead frame 210 The receiver 300 fixed to the case LED package 301 The case and the external communication part 302 The heat sink outside the case

Claims (4)

A substrate of an LED package having an LED element mounted thereon and having no heat sink, a part of the narrowest part of an n electrode connected to the n pole of the LED element and a p electrode connected to the p pole of the LED element Alternatively, in the LED package substrate that is entirely filled with ceramics and in which the n electrode and the p electrode are formed by a lead frame,
An LED package substrate in which at least a part of the lead frame of the previous period extends toward a lower temperature at a temperature different from the direction of the LED elements by at least 10 mm with respect to the surface on which the elements of the lead frame are mounted. The LED package substrate according to claim 1, wherein the lead frame is made of copper or a copper compound having a thermal conductivity of 300 W / m · K or more. The LED package substrate according to claim 1, wherein an extended portion of the lead frame is fixed to an LED illuminator housing. The part of the extended part of the lead frame protrudes outside the housing of the LED lighting device or is fixed in contact with a heat sink attached to the outside of the housing. Item 3. The LED package substrate according to Item 2.

Images