JP2011210975A - Method of manufacturing substrate for lighting device and substrate for lighting device - Google Patents

Abstract

An LED is a light-emitting element that generates heat, and the drive current of the LED cannot be increased without releasing this heat. For this purpose, a metal substrate made of a metal material is employed to suppress the temperature rise of the LED. However, cracks occur in the brazing material due to the difference in thermal expansion coefficient between the metal substrate and the LED package.
SOLUTION: On an elongated metal substrate 21 made of Al, n LED packages 22 are arranged along a long side, and the anode electrode 23a (or cathode electrode) and the cathode electrode 23b (or anode electrode) are arranged. Correspondingly, a slit ST is provided penetrating from the back surface of the metal substrate 21 to the front surface, and cracking of the brazing material is prevented by the distortion of the slit ST.
[Selection] Figure 2

Description

  The present invention relates to a lighting device in which light emitting diodes (hereinafter referred to as LEDs) are provided in a row, and further relates to a method for manufacturing the mounting substrate.

  In recent years, prevention of global warming has been screamed, and various countermeasures have been taken around the world. In particular, each company has been developing technologies to suppress the generation of carbon dioxide, such as so-called energy generation such as solar cells and wind power generation, energy storage such as fuel cells, and high-efficiency energy saving such as inverters. Yes.

  And as one of this energy saving, LED attracts attention. In other words, this light-emitting diode can be driven with considerably less power than that of incandescent bulbs and fluorescent lamps. Therefore, it is used as a backlight of a large-sized liquid crystal TV, used for home lighting, and further used as a headlight of a car.

  However, this LED has a troublesome temperature characteristic. For example, it is discussed in FIG. 5 of Japanese Patent Laid-Open No. 2001-203395.

  According to the explanation, as shown in FIG. 9, when the surface temperature of the LED chip (the temperature of the operation region) exceeds about 80 to 95 degrees C, the light quantity of the LED is increased even if the drive current is increased. Does not increase, but conversely decreases.

The curve plotted with x at the bottom is the current vs. surface temperature curve of the Al substrate, the curve plotted with the middle triangle is the current vs. surface temperature curve of the PCB substrate, and the curve with the upper peak is the current Therefore, if the temperature of the LED is lowered as much as possible and the amount of light is not increased with respect to the drive current, no further increase in the amount of light can be expected. For example, when a printed circuit board is used as an LED mounting board, the surface temperature rises as much as 230 degrees because the thermal conductivity is small, and the amount of light does not increase even when a large amount of current is passed. However, since the metal substrate has a high thermal conductivity, the surface temperature of the LED can be maintained at about 85 degrees. This effectively works as a heat sink and as a heat sink, and the metal substrate works effectively, lowers the surface temperature of the LED, so that the drive current can be increased correspondingly, and the amount of light can be increased accordingly. As described above, in order to realize a reduction in the surface temperature of the LED, it is necessary to dissipate heat generated in the light emitting diode to the outside as much as possible.

  Candidates for mounting substrates with excellent heat dissipation include metals such as Al and Cu, alloys, ceramics such as alumina and AlN, etc., but from the recent ecological thinking, light weight Al is attracting attention. . Compared to Cu, the thermal conductivity is slightly inferior, but the most important point is that the cost is low and the weight is light.

JP 2001-203395 A

  However, this metal substrate has a difficult point. It is a coefficient of thermal expansion. Specific numerical values are listed below.

Al: 23-25 ppm / degree C
Semiconductor element: 3.5 ppm / degree C
Chip resistance: 7.0 ppm / degree C
Chip capacitor: 10.0 ppm / degree C
Solder: 23 ppm / degree C
In other words, it is possible to mount the LED and release the heat generated from the LED, but as can be seen from this figure, the weakest is when the thermal expansion coefficient of the LED, which is the mounting substrate, is significantly different from that of the mounting substrate. A large load is applied to the part.

  For example, FIG. 8 shows the principle, and the arrows indicate the thermal expansion coefficient, that is, the expansion / contraction with respect to temperature. Naturally, since the elongation of the metal substrate is large, a load is applied to the solder. In particular, as the angle between the portion indicated by a circle, that is, the solder extended surface and the back surface of the element is an acute angle, the load applied thereto increases.

  Specifically, LED packages in which LEDs are sealed with a ceramic package and LED packages that are mounted on a lead frame and resin-sealed are mounted via solder from the viewpoint of mountability, but because the thermal expansion coefficient of the Al substrate is large A large load is applied to the solder. As time elapses, solder cracks occur, the circuit becomes open, and the LED does not emit light. In the lead frame, there is relaxation of stress due to the flexibility of the lead, but when sealed with a ceramic substrate, it is generally provided on the back surface of the electrode because it employs a structure in which the electrode is attached to the back surface of the ceramic substrate. A load is directly applied to the solder and the occurrence of solder cracks is significant.

The present invention, first,
Prepare a metal substrate where the surface is covered with an inorganic insulating film or the metal material is exposed,
At least a mounting substrate is an LED package made of a ceramic substrate, and a slit is formed in the metal substrate corresponding to an anode electrode (or cathode electrode) and a cathode electrode (or anode electrode) of the LED package,
A Cu foil is attached to the surface of the metal substrate via a resin layer,
This is solved by patterning the Cu foil corresponding to the anode electrode (or cathode electrode) and the cathode electrode (anode electrode).

Furthermore, a ceramic substrate, an LED chip mounted on the ceramic substrate, an anode electrode (or a cathode electrode) and a cathode electrode (which are electrically connected to the LED chip and provided on the back surface of the ceramic substrate) Or n LED packages having at least an anode electrode),
A metal substrate mainly composed of slender Al capable of arranging and arranging the n LED packages;
A slit provided correspondingly between the anode electrode (or cathode electrode) and the cathode electrode (or anode electrode) and penetrating from the back surface to the surface of the metal substrate;
An insulating layer made of a resin provided on the entire surface of the metal substrate including the opening of the slit;
A first electrode and a second electrode provided on the surface of the insulating layer, corresponding to the anode electrode (or cathode electrode) and the cathode electrode (or anode electrode);
The first electrode and the anode electrode (or cathode electrode), the second electrode and the cathode electrode (or anode electrode) are fixed by a brazing material, and the n pieces are disposed along the long side of the metal substrate. This is solved by mounting the LED package.

  In the present invention, first, in the LED package containing the LED chip, an electrode for heat dissipation is provided in addition to the electrode, so that heat generated from the LED is positively transmitted to the mounting substrate. The back surface of the LED chip is connected to the electrode of the ceramic substrate and adopts a structure that is transmitted to the heat dissipation electrode on the back surface of the ceramic substrate through a thermal via.

  In addition, a slit is formed in the mounting substrate on which the LED is mounted to relieve the stress applied to the solder. However, the slit is solved by inserting the slit at a stage before coating the insulating resin.

  Further, the crack can be further prevented by coating the mounting substrate having the slit with a resin coating so as to surround the solder. In particular, an epoxy resin or an epoxy resin containing a filler is preferable instead of a relatively flexible resin such as silicon. This is because a compressive stress always acts on the portion of the solder to which the stress is applied.

  In particular, in consideration of the temperature of the mounting substrate, a thermal via structure LED package and a mounting substrate with a slit, a thermal via structure LED package and a solder-coated portion disposed on the mounting substrate, or a thermal via structure The LED package is placed on a mounting substrate with a slit and coated with a resin to reduce solder stress as much as possible.

It is a figure explaining the illuminating device of this invention. It is a figure explaining the illuminating device of this invention. It is a figure explaining the manufacturing method of the illuminating device of this invention. It is a figure which shows the manufacturing method of the illuminating device of this invention. It is a figure which shows the manufacturing method of the illuminating device of this invention. It is a figure which shows the manufacturing method of the illuminating device of this invention. It is a figure which shows the manufacturing method of the illuminating device of this invention. It is a figure explaining the conventional illuminating device. It is a figure explaining the surface temperature of light quantity with respect to current when LED is mounted on an Al substrate and a printed circuit board. It is a figure explaining the illuminating device of this invention.

  As shown in FIG. 1A, the present invention is a technique related to an LED module 3 in which an LED package 1 which is a package in which an LED chip is sealed is mounted on a metal substrate 2, and is particularly a solder that represents solder. It relates to exhaustion and deterioration of materials.

  In particular, the metal substrate 2 may be composed of Cu or Al as a main component or a metal alloy. However, considering mounting on a vehicle or LCD TV, etc., the description will be made with Al or Al as the main material because of its light weight. The Al substrate 2 has a thickness of approximately 1.0 mm to 2.0 mm (for example, 1.5 mm), and both main surfaces are covered with an inorganic insulating film (alumite film) 4 mainly composed of an aluminum oxide film. . Further, the upper surface of the substrate 2 is entirely covered with an insulating layer 5 made of a resin filled with a filler, and a conductive pattern 6 made of Cu is formed on the upper surface of the insulating layer. Note that the inorganic insulating film may be omitted. As a matter of course, the insulating layer 5 itself has a large thermal resistance, but the thermal resistance can be reduced by the filling amount of the filler.

  Next, the LED package 1 will be described. The bare LED chip 7 is mounted on a ceramic substrate 8. The ceramic substrate 8 is provided with conductive patterns 9a to 9c on the front surface for the bare chip mounting, and correspondingly conductive patterns 10a to 10c on the back surface. Here, 9a and 10a are anode (or cathode) electrodes (hereinafter referred to as A electrodes) of LEDs, and 9b and 10b are cathode (or anode) electrodes (hereinafter referred to as C electrodes), each of which is a through hole. It is electrically connected via via. Further, the island 9c thermally coupled to the back surface of the bare chip is thermally coupled to a heat radiation electrode (hereinafter referred to as Rd electrode) 10c provided on the back surface of the ceramic substrate 8 through a thermal via 11. Yes. The thermal via 11 is obtained by firing a metal paste having a high thermal conductivity, and in particular, Ag or Cu is adopted. Furthermore, considering simplification of the manufacturing method, the same material as the through hole via may be used. The electrodes 10a and 10b extend upward from the back surface of the ceramic substrate 8 along the side surfaces. In the cross-sectional view, the L-shape is horizontal.

  Subsequently, a frame body 12 serving as four side surfaces of the LED package 1 is provided around the ceramic substrate 8, and an inner side of the frame body 12 serves as a cavity 13 for mounting the bare chip 7. Further, considering the sealing of the cavity 13 and the transmission of LED light, the light-transmitting lid 14 is fixed to the frame head with an adhesive.

  In the present invention, the heat generated from the bare chip 7 of the LED is released to the metal substrate 2 via the thermal via 11, so that the temperature rise of the bare chip 7 can be suppressed, and the drive current of the LED can be supplied accordingly. Furthermore, as shown in FIG. 2, a plurality of LED packages 1 and several dozen or more LED packages 1 are mounted on the LED bar, so the temperature of the entire LED module 3 inevitably rises. However, since the metal substrate 2 is employed, it can function as a heat sink or a heat sink, and defects due to temperature rise can be suppressed.

  Furthermore, the present invention employs a structure in which the solder of the Rd electrode 10c is sacrificed for the patterns of the back electrodes 10a and 10b and the Rd electrode 10c. That is, the electrodes 6a and 6b are conductive patterns attached to the metal substrate 2, and correspondingly, the anode electrode and the cathode electrodes 10a and 10b on the LED package 1 side are fixed via the brazing material. Similarly, the electrode 6c is a conductive pattern adhered to a metal substrate, and is fixed to the Rd electrode 10c provided on the back side of the ceramic substrate 8 via a brazing material. The structure is such that cracks are generated in the solder of the heat radiation electrode 10c. As a result, the stress applied to the solder of the electrodes 10a and 10b at both ends is relaxed to suppress cracks.

  Specifically, the angle between the solder extended surface and the back surface of the metal substrate 2 will be described below. First, some definitions will be made with reference to FIG.

  The surface where the solder is melted generally draws a curved curve. For example, FIG. 1B schematically shows the solder state of the heat radiation electrode 10c in FIG. 1A and the electrode 6c on the metal substrate side. The line L1 is the bottom surface of the ceramic substrate 8, and the line L2 indicates the surface on the metal substrate 2 side. An Rd electrode 10c is provided on the ceramic substrate 8 side, and an electrode 6c is provided on the metal substrate 2 side. The solder is wet between the two and is electrically connected.

  Originally, the angle between the extended surface of the solder and the ceramic substrate is discussed, but here it is as follows. That is, the solder starts from the point B ′ of the heat radiation electrode 10c and ends at the point A of the electrode 6c of the metal substrate. And draw a curve between the end point A and get wet. The former solder surface is regarded as a straight line A-B ', and the latter solder surface is regarded as a straight line AB. Since the solder draws a curve at any position between the two extended surfaces, the angle between the two straight lines and the horizontal line is collectively defined as α3. This point is also described in FIG. 1A, and α3 shown on both sides of the heat dissipation electrode 10c is substantially the same as α3. In the same manner, the solder extending surface inside the anode electrode and the cathode electrode was set to α1. On the other hand, α2 is a generic term for the angle between the line L3 parallel to the side wall and the straight line AB or straight line A-B ′.

  Originally, as described in the conventional example, the angles α1 to α3 are preferably obtuse angles. However, in the present invention, the electrode 6c is made slightly larger than the heat radiation electrode 10c, and provided so that the heat radiation electrode 10c enters the electrode 6C in plan view, α3 is an acute angle.

  The LED module 3 is constantly subjected to a temperature cycle, and the solder is exhausted with time. Eventually, there is a difference in time, but finally, a solder crack occurs. Therefore, at that time, the stress applied to the portions α1 and α2 is relieved by intentionally generating a crack in this portion α3.

  Although the present embodiment has been described with a ceramic package, it can be applied to a resin package as long as it has the same structure.

  Subsequently, a second embodiment will be described with reference to FIGS. This embodiment is based on the LED bar 20 that is attached to the side of the LCDTV and forms one configuration of a backlight. The metal substrate 21 and the LED package 22 may have the same configuration as the previous embodiment. good. In the previous example, the angle with the solder surface was discussed, but the future point is the slit.

  First, the substrate here uses Al or a metal substrate 21 whose main material is Al as a metal material, has a thickness of about 1.0 mm to about 2.0 mm, and a planar size of about 0.5 cm in width. The length is about 50 cm. This length varies depending on the size of the TV, but as a rule, it has an elongated shape as shown in FIG. Further, the width of the LED is essentially the same as the thickness of the light guide plate attached to the LCDTV, and since the thickness of the LCDTV has recently been reduced, this width tends to be narrower from 0.5 mm.

  The elongated metal substrate 21 is provided with LED packages 22 arranged in a line as shown in FIG. In particular, the LED packages are generally connected in series as shown in the equivalent circuit of FIG. Moreover, in order to disperse the elongation resulting from the thermal expansion coefficient as much as possible, several LED bars may be used and connected in parallel. This is because the voltage applied to both ends can be lowered, and if any LED chip malfunctions, it can be easily replaced.

  Therefore, electrodes and wirings are formed on the metal substrate 21 corresponding to the equivalent circuit. In particular, the LED package 22 is provided with the A electrode, the C electrode, and the Rd electrode as described with reference to FIG. 1A. In FIG. 2C, reference numerals 23a, 23b, and 23c correspond to the LED package 22, Itself is indicated by a dotted line.

  FIG. 2B is an enlarged view of a portion indicated by a circle in FIG. 2A, and shows a conductive pattern provided in a mounting region of one LED package. 2C is a cross-sectional view taken along the line YY, and FIG. 2D is a cross-sectional view taken along the line XX. The greatest point of the present embodiment is that a slit ST is provided between the electrodes, and FIG. 2 (E) schematically shows the effect. Although it can be easily inferred from the arrow in FIG. (E), the drawing shows that the stress generated by the expansion of the metal substrate 21 is reduced by the slit.

  Returning to FIG. 2B, the lower end of the paper has a conductive pattern 23a serving as a terminal and A electrode, and the upper end includes a conductive pattern 23b serving as a C electrode. A pattern 23c is provided. The A electrode and the C electrode are electrically connected to the electrodes of another LED package located above through wiring, but the Rd electrode 23C is used for heat dissipation, so it is floating, Express. In addition, the said wiring is extended along a side as shown with a dotted line.

  A feature of the present invention is that slits ST are provided between the A electrode 23a and the Rd electrode 23c, between the C electrode 23b and the Rd electrode 23c, or both.

Here, when the Rd electrode 23c is omitted, a slit ST may be provided between the A electrode and the C electrode.
However, since this slit ST is formed by punching, it has the following problems. That is, the LED package 22 itself is small, and the formation area of the slit ST is very narrow. Specifically, the slit ST having a width of about 0.3 cm, a length of about 1 mm, and a slit ST must be provided. Furthermore, as described with reference to FIG. 1, an inorganic insulating film made of alumite is provided on the surface of the metal substrate, and the insulating layer 5 contains a filler such as silica or alumina and is hard. There is. In particular, since the opening area of the slit ST is elongated as shown in the figure, the die (blade) of the punch is also elongated, so that the mold is heavily worn. In order to solve this problem, the present invention employs the method from FIG.

  That is, the problem is solved by forming the slit ST before the formation of the insulating layer 5. That is, wear of the mold generated by the filler of the insulating layer is prevented. There are two types of metal substrates 2 made of Al. As shown in FIG. 3, there are a type in which the inorganic insulating film 4 is formed on both surfaces of the Al substrate and a type in which the inorganic insulating film 4 is not generated. is there. In the type that is not generated, the back surface of the metal substrate 2 is easily scratched, and if it is generated, it is difficult to be scratched.

  Then, it demonstrates concretely. First, as shown in FIG. 3, a large metal substrate 2 is prepared. As described above, the front and back surfaces of the substrate 2 are of a type in which Al is exposed on the entire surface, or a type in which the inorganic insulating film 4 is formed on the front and back surfaces. In either case, punching is applied to the area of the slit ST in this state, and the metal substrate 2 is punched from the front side to the back side. A portion indicated by a dotted line 30a is a formation area of the LED package 22, and is finally a portion that is divided along this line. And here, the said formation area is integrally formed along with 30a-30d. The small squares shown in the formation areas 30a to 30d are portions where the slits ST are formed.

  In addition, as shown in FIG.3 (C), you may give twice. That is, in an area that is slightly larger than the area corresponding to the slit ST of the metal substrate 2, when a light and shallow press is performed from the front, a shallow groove GV is formed, and then corresponds to the slit ST so as to penetrate from the back to the front. Form by punching the part. By doing so, no metal burrs are generated on the back surface, and the back surface can be brought into contact with the housing or the radiation fin without any gap. Further, although burrs are generated on the front side, they are hidden in a shallow groove and do not pierce into the insulating layer 5. Therefore, there is no wiring short circuit due to burrs.

  Subsequently, as shown in FIG. 4, the insulating layer 5 containing filler and the Cu foil 31 are bonded to the surface of the metal substrate 2. Here, the sheet | seat in which the insulating layer 5 mentioned above was provided in the back surface of Cu foil 31 of a large sized substrate is prepared, and this is bonded together by thermocompression bonding. Since the size of the slit ST is small and there is not much fluidity even if the insulating layer 5 is melted, it remains on the surface of the slit ST.

  Subsequently, as shown in FIG. 5, the Cu foil 31 is patterned. In this method, a photoresist is applied on the Cu foil, portions other than the conductive pattern are removed, and the exposed Cu is etched with an etchant such as ferric chloride. The completed conductive pattern has at least an A electrode 23a, a C electrode 23b, and an Rd electrode 23c, and wirings, terminals, and the like are formed as necessary. In this state, the Cu foil is removed from the portion corresponding to the slit ST, but it is covered with the insulating layer 5.

  As shown in FIG. 6B, the insulating layer 5 corresponding to the slit ST may be removed. In FIG. Depending on the material of the insulating layer, the type of filler, and the mixing ratio, it may be brittle. In that case, it may be removed positively. In addition, when removing, it is removed by etching or laser, but as shown in the figure, it is removed with a size one size larger than the size of the slit ST. If it is a laser, only the insulating layer containing the filler can be removed by the ablation effect. By removing, microscopic warping of the slit ST is likely to occur, leading to stress relaxation. Furthermore, it is possible to remove burrs through the removal region 32. Burrs can be removed by washing with water or etching.

  In FIG. 6B, the surface of Al formed by punching is exposed from the removal region, which may cause a short circuit. However, if the insulation layer is left without forming the removal region, such a problem does not occur. .

  Finally, as shown in FIG. 7, there is a process of mounting the LED package and separating it into the LED bar 20. There are two main ways.

  That is, as shown in FIGS. 7A and 7B, the LED package 20 is mounted on the large metal substrate as it is and then separated as the LED bar 20, and as shown in FIGS. 7D and 7E. In this method, the metal substrate for the LED bar is separated along the dotted line in advance, and then the LED package 22 is mounted.

  In FIG. 7C, when the slit ST2 is provided at the boundary of the LED bar 20 and the surrounding frame body 33 is held by the thin coupling body 34, it can be easily separated even after mounting.

  Finally, the type of the electrode on the back surface of the LED chip will be described with reference to FIG. This is a type in which an anode (or cathode) electrode is provided on the front surface of the LED chip and a cathode (or anode) electrode is provided on the back surface. Although simple, the structure is shown in the LED package of FIG.

  In this case, an anode (or cathode) electrode and a cathode (or anode) electrode are provided on the front and back of the ceramic substrate corresponding to the above-described electrodes. In particular, in a thermal via for heat dissipation, a through hole via provided in a cathode (or anode) electrode becomes a thermal via. In the hollow part of the package, since the back surface of the chip functions as an electrode, a single thin metal wire can be realized.

In this case, on the metal substrate side of Al, the first electrode and the second electrode are provided corresponding to the anode (or cathode) electrode and the cathode (or anode) electrode of the LED package. The slit is formed between the first electrode and the second electrode.

  Here, only the LED package has a different structure, and the embodiment described above can be applied to the structure on the metal substrate side. The only difference is that the cathode electrode also serves as a heat dissipation electrode, the number of electrodes is reduced by one, and as a result, slits are formed in the first electrode and the second electrode of the metal substrate. .

1: LED package 2: Metal substrate 3: LED module 4: Inorganic insulating film 5: Insulating layer 6: Conductive pattern 7: LED bare chip 8: Ceramic substrate 9a, 10a: A electrode 9b, 10b: B electrode 9c, 10c : Rd electrode 11: Thermal via
12: Frame 13: Hollow part 14: Lid

Claims (10)

Prepare a metal substrate where the surface is covered with an inorganic insulating film or the metal material is exposed,
At least a mounting substrate is an LED package made of a ceramic substrate, and a slit is formed in the metal substrate corresponding to an anode electrode (or cathode electrode) and a cathode electrode (or anode electrode) of the LED package,
A Cu foil is attached to the surface of the metal substrate via a resin layer,
A method for manufacturing a substrate for a lighting device, wherein the Cu foil corresponding to the anode electrode (or cathode electrode) and the cathode electrode (anode electrode) is patterned. The LED package has a heat dissipation electrode between the anode electrode (or cathode electrode) and the cathode electrode (or anode electrode),
The slit is formed in the metal substrate corresponding to the gap between the anode electrode (or cathode electrode) and the heat dissipation electrode or between the cathode electrode (or anode electrode) and the heat dissipation electrode when forming the slit. The manufacturing method of the board | substrate for illuminating devices of 1. The said cathode electrode (or anode electrode) is a manufacturing method of the board | substrate for illuminating devices of Claim 1 which also serves as a thermal radiation electrode. A groove having a size slightly larger than the slit is formed on the surface of the metal substrate corresponding to the slit, and the slit is punched from the back surface of the metal substrate corresponding to the groove to the surface of the metal substrate. The manufacturing method of the board | substrate for illuminating devices of Claim 2 or Claim 3 which was said. The said metal substrate is a manufacturing method of the board | substrate for illuminating devices of Claim 2 or Claim 3 with which the said LED package is arranged in multiple numbers and is a vertically long shape in the direction of the said arrangement | sequence. 6. The method for manufacturing a substrate for a lighting device according to claim 5, wherein the metal substrate is a large substrate in which a plurality of the vertically long shapes are arranged in a direction intersecting the arrangement direction. A ceramic substrate, an LED chip mounted on the ceramic substrate, and an anode electrode (or cathode electrode) and a cathode electrode (or anode electrode) electrically connected to the LED chip and provided on the back surface of the ceramic substrate N LED packages having at least
A metal substrate mainly composed of slender Al capable of arranging and arranging the n LED packages;
A slit provided correspondingly between the anode electrode (or cathode electrode) and the cathode electrode (or anode electrode) and penetrating from the back surface to the surface of the metal substrate;
An insulating layer made of a resin provided on the entire surface of the metal substrate including the opening of the slit;
A first electrode and a second electrode provided on the surface of the insulating layer, corresponding to the anode electrode (or cathode electrode) and the cathode electrode (or anode electrode);
The first electrode and the anode electrode (or cathode electrode), the second electrode and the cathode electrode (or anode electrode) are fixed by a brazing material, and the n pieces are disposed along the long side of the metal substrate. A lighting device characterized in that the LED package is mounted. The wiring board is provided on the metal substrate in addition to the first electrode and the second electrode, and the n LED packages are connected in series along a long side of the metal substrate. The lighting device described. Between the anode electrode (or cathode electrode) and the cathode electrode (or anode electrode) on the back surface of the ceramic substrate, a heat dissipation electrode for releasing the heat of the LED chip is provided,
The lighting device according to claim 7 or 8, wherein the slit is provided between the anode electrode (or cathode electrode) and the heat dissipation electrode, or between the cathode electrode (or anode electrode) and the heat dissipation electrode. The lighting device according to claim 7 or 8, wherein the cathode electrode (or anode electrode) also serves as a heat dissipation electrode of the LED chip, and the via in the ceramic substrate also serves as a thermal via and a through hole via.

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