JP5235105B2 - Light emitting device - Google Patents

Description

  The present invention relates to a light emitting device, for example, a light emitting device using a high output type light emitting diode.

  Light emitting diodes are used in various places because of their small size, long life, and ease of use. In recent years, with the improvement of luminous efficiency, many high-output type light emitting diodes for illumination have been commercialized. As a high output type light emitting diode, for example, a light emitting element whose light output is increased by using a plurality of relatively small light emitting elements of about 0.3 mm square, for example, a relatively large light emitting element of about 1.0 mm square. There are known ones that increase the light output by flowing a large current, or those that further increase the light output by using a plurality of relatively large light emitting elements.

  When the power consumption of the light emitting diode is increased by using a large number of light emitting elements or by passing a large current, the amount of heat generated increases accordingly. It is known that when the temperature of the light emitting diode rises due to heat generation, it adversely affects characteristics such as the lifetime and output efficiency of the light emitting diode. Specifically, as the temperature rises, the lifetime of the light-emitting element may be shortened, or the peripheral member such as a transparent silicon resin sealing the light-emitting element may be discolored, resulting in a decrease in transparency and a decrease in light output. is there. For this reason, the heat dissipation countermeasure accompanying the increase in power consumption becomes an important subject.

As a conventional heat dissipation measure, as shown in FIG. 10, a blue light-emitting element 1 sealed with a translucent resin body 2 is fixed on a heat-radiating block 3 having high thermal conductivity, and this blue light-emitting element is emitted. A light emitting diode 10 in which a circuit board 4 is disposed so as to surround the element 1 is known (see, for example, Patent Document 1). The light emitting element 1 is die-bonded to the heat dissipation block 3 with an adhesive or the like, and the element electrode portion is electrically connected to the wiring pattern of the circuit board 4 made of an insulating material such as glass epoxy resin or BT resin by the bonding wire 5. It is connected. Since the heat generated by the light emission of the light emitting element 1 is radiated through the heat radiating block 3, the heat radiating efficiency can be improved by contacting / disposing the heat radiating block 3 on the housing 6 of the electronic device.
JP 2006-005290 A

  When the light-emitting diode 10 described in Patent Document 1 is used as, for example, a lighting fixture, the wiring pattern 7 of the circuit board 4 is connected to the electrical conduction pattern 9 of the wiring board 8 with solder 11 as shown in FIG. Is done. The heat dissipation block 3 is attached to the housing 6 with a sheet 12 made of silicon gel or silicon rubber having high heat dissipation and cushioning properties interposed therebetween.

  The sheet 12 is interposed between the heat radiating block 3 and the housing 6 because the heat radiating block is caused by the distortion of the wiring board 8, the inclination of the light emitting diode 10 due to variations in the amount of solder applied, and the flatness of the housing 6. This is because the heat radiation effect through the housing 6 is difficult to obtain. Further, if the heat dissipating block 3 is directly attached to the housing 6, stress may act on the electronic components mounted on the wiring board 8 due to distortion, which may cause a failure.

  As such a sheet 12, a sheet having a thermal conductivity of about 1 W / m · K to 5 W / m · K is usually used. There is a sheet having a thermal conductivity of 5 W / m · K or more, but it is very expensive and is difficult to use for a normal product. Further, even a sheet having a high thermal conductivity is at most about several tens of W / m · K, so that the heat dissipation effect is not necessarily sufficient, and the heat generation of the light emitting diode 10 cannot be sufficiently suppressed.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a light-emitting device that can suppress heat generation of a light-emitting diode with a simple and inexpensive configuration.

To achieve the above object, the present invention includes a light emission element, a light emitting diode wherein the light emitting element is mounted comprises a heat sink block for dissipating heat generated from the light emitting element to the outside, the light emitting element A circuit board placed on the heat dissipation block so as to surround it, a wiring pattern having a heat dissipation pattern electrically connected to an electrode of the light emitting diode, and a heat dissipation pattern, the heat dissipation block, and the heat dissipation function A heat conduction part that connects at least one of a pattern and the electrical conduction pattern, and heat generated by the light emitting diode is dissipated from the wiring board through the heat conduction part. .

  In the light emitting device configured as described above, the heat dissipating block included in the light emitting diode is connected to the heat dissipating pattern or the electric conduction pattern of the wiring board through the heat conducting portion, and the heat of the light emitting diode is dissipated from the wiring board. Thus, heat generation of the light emitting diode can be suppressed with a simple and inexpensive configuration. As a result, discoloration of the peripheral members of the light emitting element can be prevented and a decrease in light output can be suppressed. Further, it is possible to prevent a decrease in output due to heat generation of the light emitting element.

  Further, the present invention is characterized in that at least a part of the electric conduction pattern and the heat radiation pattern are connected.

  In the light emitting device configured as described above, since at least a part of the electrical conduction pattern is connected to the heat radiation pattern, the heat radiation area is increased, and the heat of the light emitting diode is efficiently radiated from the wiring board. be able to.

  In the invention, it is preferable that the heat conducting unit includes a positioning mechanism that positions a position of the light emitting diode with respect to the wiring board.

  In the light emitting device configured as described above, the light emitting diode is positioned with respect to the wiring board by the positioning mechanism provided in the heat conducting unit, so that the positional deviation of the light emitting diode can be prevented. Therefore, the occurrence of uneven color on the irradiated surface can be suppressed.

  In the present invention, the positioning mechanism includes a locking portion provided in the heat conducting portion and an engagement portion formed on the wiring board, and the locking portion is engaged with the locking portion. Thus, the light emitting diode is positioned.

  In the light emitting device configured as described above, the positioning mechanism includes an engaging portion provided in the heat conducting portion and an engaging portion formed on the wiring board, and the engaging portion is engaged with the engaging portion. Thus, positioning of the light emitting diode is performed, so that the positional deviation of the light emitting diode can be reliably prevented by a simple mechanism.

The present invention further includes a lens member for condensing or diffusing the light emitted from the light emitting diode,
A part of the lens member is fitted into a hole or notch formed in the wiring board, and the relative position between the lens member and the wiring board is positioned.

  In the light emitting device configured as described above, a part of the lens member is fitted into a hole of the wiring board and the relative position between the lens member and the wiring board is determined. In combination with a positioning mechanism for positioning the lens member, the lens member and the light-emitting diode can be fixed at a predetermined correct position, and a positional shift between the two can be prevented, and loss such as reflection on the lens member can be reduced. A high-output light-emitting device can be obtained.

  Further, the present invention is characterized in that a black resist is provided on the surface of the wiring board.

  In the light emitting device configured as described above, since the black resist is provided on the surface of the wiring board, heat can be efficiently radiated from the wiring board into the air, and the heat generation of the light emitting diode can be more effectively suppressed. .

  According to the present invention, the heat dissipating block provided in the light emitting diode is connected to the heat dissipating pattern or the electric conduction pattern of the wiring board through the heat conducting portion, and the heat of the light emitting diode is dissipated from the wiring board. It is possible to suppress the heat generation of the light emitting diode with a simple and inexpensive configuration. As a result, discoloration of the peripheral members of the light emitting element can be prevented and a decrease in light output can be suppressed. In addition, it is possible to prevent an output decrease due to heat generation of the light emitting element.

  Hereinafter, a light emitting device according to each embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a perspective view of the light emitting device according to the first embodiment of the present invention as viewed from the back side, and FIG. 2 is a longitudinal sectional view of the light emitting device shown in FIG. Note that FIG. 2 is shown upside down.

  As shown in FIGS. 1 and 2, the light emitting device 100 according to the first embodiment includes a wiring board 21 and a light emitting diode 20 mounted on the wiring board 21. The light emitting diode 20 is fixed to a substantially central portion of a substantially rectangular parallelepiped heat radiation block 22 made of a material having high thermal conductivity by die bonding with an adhesive or the like. A circuit board 24 is placed on the heat dissipation block 22 so as to surround the light emitting element 23.

  The circuit board 24 is made of an insulating material such as glass epoxy resin or BT resin (Bismaleimide Triazine Resin). The heat dissipation block 22 is made of a metal material such as copper, copper alloy, aluminum, or aluminum alloy having a high thermal conductivity, or a non-metal material such as aluminum-based ceramics in order to enhance the heat dissipation effect.

  An element electrode portion (not shown) of the light emitting element 23 is electrically connected to a wiring pattern of the circuit board 24 by a bonding wire (none is shown). The light emitting element 23 is sealed with a resin 25 having translucency such as a transparent silicon resin.

  The wiring board 21 is made of, for example, an insulating material such as glass epoxy resin or BT resin, and an electrical conduction pattern 26 and a heat dissipation pattern 27 are formed on the back surface (upper surface in FIG. 1). The electrical conduction pattern 26 of the wiring board 21 is electrically connected to the wiring pattern (not shown) of the light emitting diode 20 (circuit board 24) by soldering 28.

  The heat dissipating pattern 27 is connected to the heat dissipating block 22 by a conductive paste 30 which is a heat conducting part. That is, the conductive paste 30 is continuously applied to the heat dissipation pattern 27, the circuit board 24, and the heat dissipation block 22. Thereby, the heat of the heat dissipation block 22 is conducted to the heat dissipation pattern 27 through the conductive paste 30. The conductive paste 30 is a commercially available conductive paste, and is also a heat conductive member having a thermal conductivity of about 1 W / m · K to several tens of W / m · K.

  Such a light-emitting device 100 is attached to a housing 32 such as a lighting fixture via a sheet 31 made of silicon gel or silicon rubber having high thermal conductivity, low hardness, and high cushioning properties. By attaching to the casing 32 via the highly cushioning sheet 31, the distortion of the wiring board 21 and the inclination of the light emitting diode 20 due to variations in the amount of solder applied, the poor flatness of the casing 32, etc. are absorbed, and heat is dissipated. The block 22 and the housing 32 are substantially in close contact with each other. In addition, since distortion of the light emitting device 100 due to attachment to the housing 32 is prevented and stress applied to the mounted electronic component is reduced, the failure occurrence rate of the electronic component is reduced.

  According to the light emitting device 100 of the present embodiment, the heat generated with the light emission of the light emitting element 23 is conducted from the heat radiating block 22 to the housing 32 via the sheet 31 and is radiated from the surface of the housing 32. . Furthermore, it is also conducted to the heat radiation pattern 27 through the heat radiation block 22 and the conductive paste 30, and efficiently radiated from the heat radiation pattern 27 having a large area. Therefore, the heat generation of the light emitting diode 20 can be significantly suppressed by a simple and inexpensive mechanism.

  Naturally, a larger heat dissipation effect can be expected as the area of the heat dissipation pattern 27 increases. Also, solder can be used in place of the conductive paste 30. Further, it is also effective to cover the black resist in order to increase the heat radiation from the heat radiation pattern 27 to the air.

  By suppressing the heat generation of the light emitting diode 20, an adverse effect on the life of the light emitting element 23 due to heat is prevented, and a decrease in transparency due to discoloration of the peripheral member 25 such as a transparent silicon resin sealing the light emitting element 23. It is possible to prevent the decrease in light output. Moreover, since the light emission efficiency of the light emitting element 23 increases as the temperature decreases, the light output can be increased as a result.

  In addition, the conductive paste 30 generally contains a metal such as silver, carbon, and the like, and has high electrical conductivity. Therefore, even if static electricity is applied to the heat dissipation block 22 or the like, the heat dissipation pattern is passed through the conductive paste 30. 27 and the stress applied to the light emitting diode 20 (light emitting element 23) can be reduced.

(Second Embodiment)
FIG. 3 is a perspective view of the light emitting device according to the second embodiment of the present invention as seen from the back side. The light emitting device of the second embodiment is the same as the light emitting device of the first embodiment except that the pattern of the electrical conduction pattern and the pattern of heat dissipation of the wiring board are different. A description thereof will be omitted.

  As shown in FIG. 3, a part of the electrical conduction pattern 26 and the heat radiation pattern 27 of the wiring board 21 of the second embodiment are connected by a common pattern 29. As a result, a part (common pattern portion) of the electric conduction pattern 26 can be used as the heat radiation pattern 27, and the heat radiation area is increased. Therefore, the heat of the light emitting diode 20 is further effectively radiated to generate heat. Can be suppressed.

(Third embodiment)
4 is a perspective view of a light emitting device according to a third embodiment of the present invention, and FIG. 5 is a rear perspective view of the light emitting device shown in FIG. The light emitting device of the third embodiment is the same as the light emitting device of the first embodiment except that the heat dissipation pattern of the wiring board is also formed on the substrate surface. A description thereof will be omitted.

  As shown in FIG. 4, the wiring board 21 of the third embodiment is provided with a heat radiation pattern 27A in a wide range on the surface side. The wiring board 21 is provided with a large number (four in the embodiment shown in the figure) of through holes 33, and the heat radiation pattern 27 A on the front surface side is connected to the heat radiation pattern 27 on the back surface side through the through holes 33. ing.

  Thereby, the area of the heat radiation pattern 27 can be greatly increased, and the heat of the light emitting diode 20 conducted from the heat radiation block 22 to the heat radiation pattern 27 on the back surface side can be radiated on the front surface side through the through hole 33. The heat can be further effectively suppressed by conducting the heat to the pattern 27A and dissipating heat from both the backside and frontside heat dissipation patterns 27 and 27A. Here, as the number of the through holes 33 increases, the heat of the heat radiation pattern 27 on the back surface side can be uniformly conducted to the heat radiation pattern 27A on the front surface side, and the heat radiation efficiency increases.

(Fourth embodiment)
FIG. 6 is a longitudinal sectional view of a light emitting device according to a fourth embodiment of the present invention. In the light emitting device 100 according to the fourth embodiment, the housing 32 is attached to the heat dissipation block 22 via the sheet 31, and is further fixed by screws 34 in a state where the housing 32 is in contact with the heat dissipation pattern 27 of the wiring board 21. ing. Thereby, in addition to heat radiation from the housing 32 via the sheet 31, heat conducted from the heat radiation block 22 to the heat radiation pattern 27 is also radiated from the housing 32, and the heat radiation efficiency is further improved. Further, even if static electricity is applied to the heat dissipation block 22 or the like, it can be released to the heat dissipation pattern 27, and stress applied to the light emitting diode 20 (light emitting element 23) can be reduced.

(Fifth embodiment)
7 and 8 are longitudinal sectional views of a light emitting device according to a fifth embodiment of the present invention. The light-emitting device of the fifth embodiment is the same as the light-emitting device of the third embodiment except that a fixture having a positioning mechanism is used as a heat conducting unit. A description thereof will be omitted.

  The fixture 40 is made of a metal such as copper or aluminum having high thermal conductivity, and has a main body portion 42 provided with a square hole 41 fitted in the heat dissipation block 22 at a substantially central portion, and a substantially right angle from the main body portion 42. And a pair of arm portions 43 standing upright. A claw-shaped locking portion 44 that is a positioning mechanism for the light emitting diode 20 is formed at the tip of the arm portion 43. On the wiring substrate 21, a heat dissipation pattern 27 is formed on the back surface side together with the electrical conduction pattern 26, and a heat dissipation pattern 27 </ b> A connected to the heat dissipation pattern 27 by a through hole 33 is formed on the front surface side.

  In the fixture 40 in which the heat dissipation block 22 is fitted and fixed in the square hole 41, the pair of arm portions 43 are inserted into the through holes 33, and the engaging portions 44 are engaged with the through holes 33 which are also engaging portions. Then, the positioning of the light emitting diode 20 with respect to the wiring substrate 21 is performed, and the positional deviation of the light emitting diode 20 is prevented.

  At the same time, the heat radiating block 22 is connected to the heat radiating patterns 27 and 27A via the metal fixture 40, so that the heat conducted from the light emitting element 23 to the heat radiating block 22 passes through the fixture 40. The heat is efficiently radiated from the wiring board 21 through the heat radiation patterns 27 and 27A. Although not shown, it goes without saying that the wiring pattern formed on the circuit board 24 of the light emitting diode 20 is electrically connected to the electrical conduction pattern 26 of the wiring board 21.

  In the light emitting device 100 of the present embodiment, first, after applying the cream solder to the electric conduction pattern 26 and mounting the light emitting diode 20, the arm portion 43 of the fixture 40 is inserted into the through hole 33 to attach the light emitting diode 20. Fix to the wiring board 21. And it manufactures by passing through a reflow solder tank and soldering. At this time, since the light emitting diode 20 is positioned on the wiring board 21 by the fixture 40, the position does not shift.

  In addition, as shown in FIG. 8, if the latching | locking part 44 of the fixing tool 40 is soldered to the pattern 27A for heat dissipation with the solder 28, the heat dissipation effect will increase further. Further, even if static electricity is applied to the heat dissipation block 22 or the like, it can be released to the heat dissipation pattern 27 via the metal fixture 40, and stress applied to the light emitting diode 20 (light emitting element 23) can be reduced. .

(Sixth embodiment)
FIG. 9 is a longitudinal sectional view of a light emitting device according to a sixth embodiment of the present invention. Since the light emitting device of the sixth embodiment is the same as the light emitting device of the fifth embodiment except that it includes a lens member, the same parts are denoted by the same or corresponding reference numerals, and description thereof is omitted.

  The lens member 50 includes a lens 51 that condenses or diffuses light emitted from the light emitting diode 20 and a pair of legs 52 that extend in the optical axis direction of the lens 51. A positioning pin 53 formed at the tip of the pair of leg portions 52 is fitted into a hole 54 formed in the wiring board 21 so that the relative position between the lens member 50 and the wiring board 21 is fixed.

  Thus, by fixing the lens member 50 to the wiring board 21, the lens member 50 can be positioned at a predetermined position with respect to the wiring board 21, and the positioning of the light emitting diode 20 described in the fifth embodiment can be performed. When used together with the fixture 40 to be used, it is possible to accurately position the light emitting diode 20 and the lens member 50 while preventing relative displacement. As a result, the lens performance can be sufficiently exhibited to prevent the occurrence of uneven color on the irradiated surface.

  The light emitting device of the present invention is not limited to the above-described embodiments, and appropriate modifications and improvements can be made.

  In addition, the circuit board, the heat radiation block, the light emitting diode, the electrical conduction pattern, the heat radiation pattern, the wiring board, the heat conduction unit, the light emitting device, the positioning mechanism, the locking unit, the engagement unit, and the lens exemplified in each of the above-described embodiments. The material, shape, dimension, form, number, location, etc. of the member, hole, notch, black resist, etc. are arbitrary and not limited as long as the present invention can be achieved.

The perspective view which looked at the light-emitting device which concerns on 1st Embodiment of this invention from the back surface. 1 is a longitudinal sectional view taken along line AB of the light emitting device shown in FIG. The perspective view which looked at the light-emitting device which concerns on 2nd Embodiment of this invention from the back surface. The perspective view of the light-emitting device which concerns on 3rd Embodiment of this invention. 4 is a rear perspective view of the light emitting device shown in FIG. Longitudinal sectional view of a light emitting device according to a fourth embodiment of the present invention. A longitudinal sectional view of a light emitting device according to a fifth embodiment of the present invention. FIG. 7 is a longitudinal sectional view of a light emitting device in which the fixture shown in FIG. 7 is soldered to a wiring board. Longitudinal sectional view of a light emitting device according to a sixth embodiment of the present invention Vertical section of a conventional light emitting device The longitudinal cross-sectional view of the conventional light-emitting device attached to the housing | casing through the sheet | seat.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Light emitting diode 21 Wiring board 22 Heat radiation block 23 Light emitting element 24 Circuit board 26 Electric conduction pattern 27 Heat radiation pattern 27A Heat radiation pattern 30 Conductive paste (heat conduction part)
33 Through hole (engagement part)
40 Fixing device (heat conduction part)
44 Locking part (positioning mechanism)
50 Lens member 54 Hole in wiring board 100 Light emitting device

Claims (6)

A light emitting diode comprising a light emitting element, and a heat dissipation block for dissipating heat generated from the light emitting element to which the light emitting element is mounted;
A circuit board placed on the heat dissipation block so as to surround the light emitting element;
An electrical conduction pattern electrically connected to the electrode of the light emitting diode, and a wiring board having a heat dissipation pattern;
A heat conducting part for connecting the heat dissipating block and at least one of the heat dissipating pattern and the electric conducting pattern;
With
The heat generated in the light emitting diode is dissipated from the wiring board through the heat conducting portion.   The light emitting device according to claim 1, wherein at least a part of the electric conduction pattern and the heat radiation pattern are connected.   The light emitting device according to claim 1, wherein the heat conducting unit includes a positioning mechanism that positions the light emitting diode with respect to the wiring board.   The positioning mechanism includes a locking portion provided on the heat conducting portion and an engagement portion formed on the wiring board, and the locking portion is engaged with the locking portion to 4. The light emitting device according to claim 3, wherein positioning is performed. A lens member for condensing or diffusing the light emitted from the light emitting diode;
5. The relative position between the lens member and the wiring board is determined by fitting a part of the lens member into a hole or notch formed in the wiring board. Light emitting device.   The light emitting device according to claim 1, wherein a black resist is provided on a surface of the wiring board.

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