JP5155638B2 - Light emitting device - Google Patents

Description

  The present invention relates to a light emitting device using an LED chip (light emitting diode chip).

  Conventionally, a GaN LED chip that emits blue light or ultraviolet light, and a phosphor or light absorption as a wavelength conversion material that emits light of an emission color different from that of the LED chip when excited by light emitted from the LED chip. Research and development of light emitting devices that emit light of a color different from the emission color of the LED chip, including white, by combining with the body is performed in various places (for example, see Patent Document 1), and the light output of the light emitting device is increased. Along with this, application to lighting applications is progressing.

  Here, when this type of light emitting device is used for lighting applications, in order to suppress the decrease in light emission efficiency due to the temperature rise of the LED chip, the LED chip junction temperature should be put into the light emitting device so that it does not exceed the maximum junction temperature. Generally, the power is increased to obtain a desired light output. Further, when this type of light-emitting device is used for lighting, a long-term operation life is required, and therefore, it is required to use a highly durable material as a package material.

  By the way, as a light emitting device that improves the heat radiation efficiency by improving the heat dissipation from the LED chip 1, a light emitting device having the configuration shown in FIG. 8 has been proposed (not related to known literature).

  The light emitting device having the configuration shown in FIG. 8 includes an LED chip 1 ′, a mounting substrate 2 ′ on which the LED chip 1 ′ is mounted on one surface side, and an LED chip that is excited by light emitted from the LED chip 1 ′. A dome-shaped color conversion member that is formed of a fluorescent material that emits light of a color different from the light emission color of 1 ′ and a light-transmitting material and that is disposed between the mounting substrate 2 ′ and the LED chip 1 ′. 4 '. In this light emitting device, a GaN blue LED chip is used as the LED chip 1 ′, and a yellow phosphor is used as the phosphor of the color conversion member 4 ′, so that white light can be obtained.

  Here, the mounting substrate 2 ′ is electrically connected to one surface side of the insulating substrate 21 ′ made of a thin ceramic substrate and the respective electrodes of the LED chip 1 ′ via bonding wires 14 ′ and 14 ′. Two wiring patterns 22 'and 22' are formed. Here, the wiring patterns 22 ′ and 22 ′ extend to the external connection electrodes 22b ′ and 22b ′ formed across the side surface and the other surface (the lower surface in FIG. 8) of the insulating substrate 21. Connected.

  Further, in the light emitting device described above, a heat radiating conductor portion 27 ′ for radiating heat generated in the LED chip 1 ′ is formed in the central portion of the other surface of the insulating substrate 21 ′ in the mounting substrate 2 ′. Yes. The heat radiating conductor portion 27 ′ is formed of the same material as the wiring patterns 22 ′ and 22 ′ with the same thickness, and has a larger planar size than the LED chip 1 ′. 1 'is entered.

When the light emitting device described above is mounted on the wiring board 7 ′, the external connection electrodes 22b ′ and 22b ′ are connected to the conductor pattern (land part) of the wiring board 7 ′ via the joints 83 ′ and 83 ′ made of solder. 73 ', 73' are joined and electrically connected, and the heat dissipating conductor portion 27 'is joined to the conductor pattern (land portion) 74' of the wiring board 7 'via the joint portion 84' made of solder. By heat coupling, the heat generated in the LED chip 1 ′ is transferred from the one surface of the thin insulating substrate 21 ′ to the other surface side, and passes through the heat radiating conductor portion 27 ′ and the joint portion 84 ′. Since heat is radiated to the wiring board 7, the temperature rise of the LED chip 1 ′ can be suppressed. Here, in the above-described light emitting device, the thickness dimension of the insulating substrate 21 ′ is set to about 0.3 mm in order to improve heat dissipation. Further, in order to improve heat dissipation, the wiring board 7 ′ has an insulating layer 72 ′ formed on the Cu metal plate 71 ′ and conductor pattern patterns 73 ′, 73 ′, 74 ′ formed on the insulating layer 72 ′. The metal base substrate (metal base printed wiring board) is used.
JP 2007-250817 A

  Incidentally, in the light emitting device having the configuration shown in FIG. 8, since the insulating substrate 21 ′ in the mounting substrate 2 ′ is made of ceramic, it cannot be said that the thermal conductivity is good, and the heat generated in the LED chip 1 ′. However, as indicated by the alternate long and short dash line in FIG. 9, heat is transferred to the heat radiating conductor 27 ′ without spreading in the horizontal direction. Here, if the spread angle when the heat generated in the LED chip 1 ′ is conducted through the insulating substrate 21 ′ is 45 °, from the projection region of the LED chip 1 ′ in the heat radiating conductor portion 27 ′. Since heat is transferred only to a region spread by 0.3 mm, a sufficient heat dissipation effect cannot be obtained, and it has been difficult to increase the output in order to prevent a decrease in luminous efficiency.

  In the above light emitting device, alumina is generally used as the ceramic of the insulating substrate 21 ′. However, even if the thickness of the insulating substrate 21 ′ is set to 0.3 mm, the thermal resistance is 10 ° C. / W, which is a factor that hinders heat dissipation.

  In the light emitting device described above, the external connection electrodes 22b ′ and 22b ′ on the mounting substrate 2 ′ are formed across the side surface of the insulating substrate 21 ′ and the other surface. , 22b ′ and the conductor fillets 73 ′, 73 ′ of the wiring board 7 ′ are visually checked for solder fillets at the joints 83 ′, 83 ′, so that the external connection electrodes 22b ′, 22b ′ and the conductor patterns 73 ′, It is possible to easily confirm the electrical connection state with 73 ′, but the joint 84 ′ between the heat radiating conductor 27 ′ and the conductor pattern 74 ′ of the wiring board 7 ′ is within the projection plane of the mounting board 2 ′. Therefore, it is impossible to visually check the bonding state of the bonding portion 84 ′ after mounting on the wiring board 7 ′, and the bonding state of the bonding portion 84 ′ is necessary unless a large-scale facility such as an X-ray apparatus is used. Can be confirmed No because, could not be easily confirm the bonding condition of the joint 84 '. Further, in the above-described light emitting device, flux decomposition that occurs in the melting process of the solder that forms the basis of the joint 84 ′ at the joint 84 ′ between the heat radiating conductor 27 ′ and the conductor pattern 74 ′ of the wiring board 7 ′. Gases such as components tend to remain as voids 90 ′ and remain in the joint 84 ′. When the voids 90 ′ are generated, the thermal conductivity is reduced, and furthermore, the joint is caused by a temperature cycle caused by turning on and off. Due to the stress generated at 84 ′, cracks are likely to occur with the void 90 ′ as a base point.

  The present invention has been made in view of the above-mentioned reasons, and the object thereof is high heat dissipation and easily confirms the joining state of the joint portion for thermal coupling with the wiring board after mounting on the wiring board. An object of the present invention is to provide a light emitting device capable of performing the above.

The invention of claim 1 is provided with LED chips, and the L ED mounting substrate chip is mounted, the implementation substrate, the L ED chip electrically connected to the wiring pattern is formed on one surface side other surface and an insulating substrate where the external connection electrodes are formed across the side surface, the outer peripheral line of the embedded in the other surface side peripheral line in the projection view of the insulation substrate is the L ED chip together are and a metal plate positioned on the outer side than the result provided notch exposing a side surface of the main barrel plate portion of the side surface of the insulation substrate is said LED chip and said metal plate There is a thin portion of the insulating substrate between them.

According to the present invention, the other surface side of the insulating substrate in which the wiring pattern electrically connected to the LED chip is formed on one surface side and the external connection electrode is formed across the other surface and the side surface. since peripheral line of buried projected view to have a metal plate positioned outside the peripheral line of the L ED chip, it is possible to enhance the heat radiation, moreover, the side surface of the insulation substrate that put on a mounting board by notch exposing a side surface of the main barrel plate in a part of the is provided, in the case of using and mounted on the wiring board, the wiring and the main barrel plate after mounting to the wiring substrate It becomes possible to easily confirm visually the joining state of the joint for thermal coupling with the substrate . According to the present invention, since there is a thin portion of the insulating substrate between the LED chip and the metal plate, heat generated in the LED chip passes through the thin portion of the insulating substrate. Heat is transferred to the metal plate wider than the chip and dissipated.

Another invention of the present application includes an LED chip and a mounting substrate on which the LED chip is mounted, and the mounting substrate has a wiring pattern electrically connected to the LED chip on one surface side. An insulating substrate on which external connection electrodes are formed across the other surface and the side surface, and an outer peripheral line embedded in the other surface side of the insulating substrate and positioned outside the outer peripheral line of the LED chip. to and a metal plate, wherein it said cutouts exposing a side surface of the metal plate is provided in a part of the side surface of the insulating substrate, prior Symbol metal plate, on the one surface of the insulating substrate An exposed mount portion is protruded, and the LED chip is mounted on the mount portion.

According to the another invention described above, the other of the insulating substrate in which the wiring pattern electrically connected to the LED chip is formed on one surface side and the external connection electrode is formed across the other surface and the side surface. Since the outer peripheral line in the projection view has a metal plate that is located outside the outer peripheral line of the LED chip, the heat dissipation can be enhanced, and the side surface of the insulating substrate in the mounting substrate can be improved. In the case where the metal plate and the wiring board are mounted on the wiring board, the metal plate and the wiring board are joined for thermal coupling after being mounted on the wiring board. It becomes possible to easily confirm the joining state of the parts visually. Furthermore, according to the further inventions, the so LED chips heat generated in is directly heat transfer to the metal plate without going through the insulation substrate, improved heat dissipation, thereby improving the light output At the same time, the life and reliability can be improved.

Another invention of the present application is characterized in that , in the above-mentioned another invention, the mount portion protrudes from a plane including the one surface of the insulating substrate.

According to the other invention, the light emitted from the LED chip can be reduced in components incident on and absorbed by the one surface of the insulating substrate, and the light extraction efficiency as a whole of the light emitting device can be reduced. Can be improved.

Still another invention of the present application is characterized in that , in the above-mentioned another invention or the above-mentioned other invention, the mounting portion is formed with a bonding material reservoir groove around the LED chip mounting region.

According to still another aspect of the invention, when the LED chip is joined to the mounting area of the mount portion by solder (including brazing using a gold-tin alloy or the like), excess solder overflowing from immediately below the LED chip is present. Since it accumulates in the bonding material reservoir groove, it is possible to prevent a short circuit or wire bonding failure caused by excess solder flowing out onto the wiring pattern on the one surface side of the insulating substrate.

According to a second aspect of the present invention, in the first aspect of the invention, the mounting substrate is such that the metal plate protrudes from a plane including the surface of the external connection electrode on the other surface side of the insulating substrate. Features.

According to the present invention, the can to increase the thickness of the joint portion between the external connection electrode and the conductive pattern of the wiring substrate, and the insulating substrate when the applied temperature cycle according to OFF of energization the stress caused by the wiring substrate and the linear expansion coefficient difference to the junction between the conductive material pattern of the wiring substrate and the external connection electrodes is reduced, occurrence of cracks in the joint Can be suppressed.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the metal plate has a groove that becomes wider from the center toward the outer side on the same surface side as the other surface side of the insulating substrate. It is formed.

According to the present invention, when used and mounted on the wiring substrate, when bonding by solder said main barrel plate on the wiring substrate, the gas and air bubbles, such as flux caused in the process of curing the solder melting easily escape to the outside along the grooves, the inside of the joining portion made of solder after curing can be suppressed from voids occur, consequently, the thermal resistance between the wiring substrate and the LED chip it is possible to reduce variations in, is the high resistance of the junction of the heat coupling to stress changes caused by difference in linear expansion coefficient between the insulating substrate and the wiring substrate when the temperature cycle is applied Reliability is improved.

  According to the first aspect of the present invention, there is an effect that the heat dissipation is high and it is possible to easily confirm the bonding state of the bonding portion for thermal coupling with the wiring board after mounting on the wiring board.

(Embodiment 1)
As shown in FIG. 1, the light emitting device of the present embodiment is an LED chip 1 that is excited by light emitted from the LED chip 1, a mounting substrate 2 on which the LED chip 1 is mounted on one surface side, and the LED chip 1. The LED chip 1 is formed on the one surface side of the mounting substrate 2 so as to surround the LED chip 1 between the mounting substrate 2 and formed of a translucent material containing a phosphor that emits light of a color different from the emission color of 1. The dome-shaped color conversion member 4 and the translucent seal in which the bonding wires 14 and 14 made of the LED chip 1 and the fine gold wires are sealed in a space surrounded by the color conversion member 4 and the mounting substrate 2. And a sealing portion (not shown) made of a stopper (eg, silicone resin, glass, etc.). In the present embodiment, the space surrounded by the mounting substrate 2 and the color conversion member 4 is enriched by the sealing portion that seals the LED chip 1. However, the space is filled with an air atmosphere, an inert gas atmosphere, A vacuum atmosphere may be used.

  In the light emitting device of the present embodiment, a GaN blue LED chip that emits blue light is used as the LED chip 1, and the phosphor of the color conversion member 4 is excited by the blue light emitted from the LED chip 1. A particulate yellow phosphor that emits broad yellow light is used, blue light emitted from the LED chip 1 and transmitted through the color conversion member 4, and yellow emitted from the yellow phosphor of the color conversion member 4. The light is emitted as a light distribution diffused from the light exit surface of the color conversion member 4, and white light can be obtained.

  Each LED (not shown) is formed on one surface side (the upper surface side in FIG. 1B) of the LED chip 1 described above, and the mounting substrate 2 is a thin ceramic substrate (for example, an alumina substrate or the like). The two wiring patterns 22 and 22 and the LED chip 1 that are electrically connected to the respective electrodes of the LED chip 1 via the bonding wires 14 and 14 are soldered to one surface side of the insulating substrate 21 made of , AuSn solder, etc.) are formed. Here, each of the wiring patterns 22 and 22 extends to the external connection electrodes 22b and 22b formed across the side surface of the insulating substrate 21 and the other surface (the lower surface in FIG. 1B). It is connected to the. The material of the insulating substrate 21 is not limited to ceramics such as alumina, but may be a heat-resistant resin such as a highly insulating glass epoxy resin or liquid crystal polymer. In this embodiment, the chip size of the LED chip 1 is set to 0.3 mm □, and the thickness of the insulating substrate 21 is set to 0.3 mm. However, these values are not particularly limited.

  Further, the mounting substrate 2 has a Cu metal plate 25 to which heat generated by the LED chip 1 is transferred on the other surface side of the insulating substrate 21, and the outer peripheral line of the metal plate 25 in a projected view. Is located outside the outer peripheral line of the LED chip 1. In short, the LED chip 1 is arranged in the projection area of the metal plate 25. Therefore, since the heat generated in the LED chip 1 is transferred to the metal plate 25 wider than the LED chip 1 through the thin portion of the insulating substrate 21 and radiated, the temperature rise of the LED chip 1 is suppressed and the light output is reduced. It is possible to improve the service life and reliability. Here, the mounting substrate 2 is provided with an embedding hole 24a in which the metal plate 25 is embedded in the central portion of the other surface of the insulating substrate 21, and the inner bottom surface of the embedding hole 24a (joined portion with the metal plate 25). ) Is plated, and the metal plate 25 is joined by brazing or the like. Here, in the present embodiment, the other surface of the insulating substrate 21 and the surface on the other surface side of the insulating substrate 21 in the metal plate 25 are substantially flush. The material of the metal plate 25 is not limited to Cu, and may be CuW, for example.

  In addition, the mounting substrate 2 is provided with a notch 21 a that exposes the side surface of the metal plate 25 at a part of the side surface of the insulating substrate 21.

  As described above, the mounting substrate 2 has the external connection electrodes 22b and 22b formed across the side surface of the insulating substrate 21 and the other surface, and the metal plate 25 on the other surface side of the insulating substrate 21. Since the conductor patterns 73 and 73 corresponding to the external connection electrodes 22b and 22b and the conductor pattern 74 corresponding to the metal plate 25 are mounted on the wiring board 7, the external connection electrodes 22b and 22b are embedded. 22b is joined to and electrically connected to the conductor patterns 73 and 73 of the wiring board 7 through the joints 83 and 83 made of solder, and the metal plate 25 is connected to the conductor pattern 73 and 73 of the wiring board 7 through the joints 84 made of solder. By joining and thermally coupling to the conductor pattern 75, the heat generated in the LED chip 1 is between the one surface of the insulating substrate 2 and the inner bottom surface of the embedded hole 24a. Heat is transferred to the metal plate 25 through the wall portion is heat transfer to the circuit board 7 with diffuse a metal plate 25 is radiated to the outside. Here, the wiring board 7 is constituted by a metal base board (metal base printed wiring board) in which an insulating layer 72 is formed on a Cu metal plate 71 and wiring patterns 73 and 75 are formed on the insulating layer 72. ing. The material of the metal plate 71 is not limited to Cu, but may be Al, for example. Further, in the light emitting device of this embodiment, heat generated in the LED chip 1 is transferred to the metal plate 25 through the thin portion between the one surface of the mounting substrate 2 and the inner bottom surface of the embedded hole 24a. From the viewpoint of reducing the resistance, it is desirable that the thickness of the thin portion is thin.

  The color conversion member 4 is formed in a dome shape using a mixed material in which a particulate yellow phosphor that is excited by blue light emitted from the LED chip 1 and emits yellow light is dispersed in a translucent material made of silicone resin. Is formed. The translucent material used as the material of the color conversion member 4 is not limited to a silicone resin. For example, an organic / inorganic hybrid in which an acrylic resin, glass, an organic component and an inorganic component are mixed and combined at the nm level or the molecular level. Materials etc. may be adopted. Further, the phosphor to be contained in the translucent material used as the material of the color conversion member 4 is not limited to the yellow phosphor, and a plurality of types of phosphors may be used for the purpose of improving color adjustment and color rendering. White light with high color rendering properties can be obtained by using a red phosphor and a green phosphor. Here, when a plurality of types of phosphors are used, the phosphor is not necessarily a combination of phosphors having different emission colors, and for example, a plurality of types of phosphors having an emission color of yellow and different emission spectra may be combined.

  By the way, the color conversion member 4 is formed in a dome shape in which the one surface side of the mounting substrate 2 is opened and each of the light incident surface and the light emitting surface is a part of a spherical surface, and is formed on the one surface side of the mounting substrate 2. Bonded by an adhesive such as silicone resin. In the present embodiment, the outer peripheral shape of the mounting substrate 2 is a rectangular shape, but is not limited to a rectangular shape, and may be a circular shape or a polygonal shape.

  The light emitting device of the present embodiment described above includes the metal plate 25 that is embedded on the other surface side of the insulating substrate 21 in the mounting substrate 2 and whose outer peripheral line in projection view is located outside the outer peripheral line of the LED chip 1. Since the metal plate 25 has higher thermal conductivity than the insulating substrate 21, the heat transferred to the metal plate 25 spreads quickly in the lateral direction, and the entire metal plate 25 reaches substantially the same temperature. When the heat dissipation can be improved and the cutout portion 21a that exposes the side surface of the metal plate 25 is provided on a part of the side surface of the insulating substrate 21, it is used when mounted on the wiring substrate 7. After mounting on the wiring board 7, it is possible to easily visually confirm the joining state of the joint portion 84 for thermal coupling between the metal plate 25 and the conductor pattern 74 of the wiring board 7.Here, in the light emitting device of the present embodiment, the surface facing the conductor pattern 74 and the exposed surface on the side surface of the metal plate 25 are bonded to the conductor pattern 74 via the bonding portion 84, and thus mounted on the wiring board 7. In the state, the joining state can be confirmed by visually confirming whether or not a fillet is formed in the joining portion 84 from the side through the notch portion 21a. Moreover, also about each external connection electrode 22b, 22b of the mounting board | substrate 2, a joining condition can be confirmed by confirming whether the fillet is formed in the junction part 83, 83 from the side. .

(Embodiment 2)
The basic configuration of the light emitting device of the present embodiment is substantially the same as that of the first embodiment, and a GaN-based blue LED chip having electrodes provided on both sides in the thickness direction is used as the LED chip 1, as shown in FIG. In addition, one of the two wiring patterns 22, 22 also serves as a die bonding part on which the LED chip 1 is mounted, and an electrode (cathode electrode) on the back side of the LED chip 1 serves as the die bonding part. The wiring pattern 22 is bonded to the wiring pattern 22 by solder (for example, AuSn solder), and the electrode (anode electrode) on the surface side of the LED chip 1 is electrically connected to the other wiring pattern 22 through the bonding wire 14. Is different. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  Further, in the light emitting device of the present embodiment, the through hole wiring 26 that electrically connects the wiring pattern 22 also serving as the die bonding portion and the metal plate 25 is formed in the thin portion of the insulating substrate 21 in the mounting substrate 2. The metal plate 25 also serves as one external connection electrode.

  Also in the light emitting device of the present embodiment, as in the first embodiment, it is visually confirmed whether or not a fillet is formed at the joint portion 84 from the side through the cutout portion 21a when mounted on the wiring board 7. Thus, the joining state can be confirmed.

(Embodiment 3)
The basic configuration of the light emitting device of the present embodiment is substantially the same as that of the second embodiment, and as shown in FIG. 3, the mount exposed from the center of one surface of the metal plate 25 to the one surface side of the insulating substrate 21. The part 25b is protruded continuously and integrally, and the LED chip 1 is different in that it is mounted on the mount part 25b. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 2, and description is abbreviate | omitted.

  The mounting substrate 2 in the present embodiment is provided with a through hole 24b into which the mount portion 25b is inserted between the one surface of the insulating substrate 21 and the inner bottom surface of the embedded hole 24a. The surface of the insulating substrate 21 and the surface of the insulating substrate 21 are substantially flush with each other.

  The LED chip 1 in the present embodiment has electrodes (not shown) formed on both surfaces in the thickness direction as in the second embodiment, and the electrode on the mounting substrate 2 side is joined to the mount portion 25 via solder, The electrode on the side opposite to the mounting substrate 2 side is electrically connected to the wiring pattern 22 via the bonding wire 14 made of a fine gold wire.

  Thus, in the light emitting device of the present embodiment, the mounting portion 25b is protruded from the metal plate 25, and the LED chip 1 is mounted on the mounting portion 25b. Therefore, the heat generated in the LED chip 1 is Embodiment 1. , 2, heat is directly transferred to the metal plate 25 without passing through the thin portion of the insulating substrate 21, so that heat dissipation is improved, light output can be improved, and life and reliability can be improved.

  The LED chip 1 may be mounted on the mount portion 25b via a submount member that relieves stress acting on the LED chip 1 due to a difference in linear expansion coefficient between the LED chip 1 and the metal plate 25. Good. The submount member in this case has not only the function of relieving the stress, but also heat conduction that transfers heat generated in the LED chip 1 to a wider range than the chip size of the LED chip 1 in the mount portion 25b of the metal plate 25. It is preferable to use a material having a larger planar size than the LED chip 1 so as to have a function, and to use a material having high thermal conductivity.

(Embodiment 4)
The basic configuration of the light emitting device of the present embodiment is substantially the same as that of the third embodiment. As shown in FIG. 4, the mount 25 b protrudes from the plane including the one surface of the insulating substrate 21. The only difference is that an annular positioning frame 28 for positioning the color conversion member 4 is provided on the one surface side of the substrate 21 (the dashed line arrow in FIG. The direction of travel of the emitted light is schematically shown). Here, the projecting dimension of the mount portion 25 from the plane is set to be larger than the total thickness of the wiring pattern 21 and the positioning frame 28. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 3, and description is abbreviate | omitted.

  Therefore, in the light emitting device of the present embodiment, the mount portion 25b protrudes from a plane including the one surface of the insulating substrate 21, so that the one surface of the insulating substrate 21 out of the light emitted from the LED chip 1 is used. The component that is incident on and absorbed can be reduced, and the protruding dimension of the mount portion 25 from the plane is set to be larger than the total thickness of the wiring pattern 21 and the positioning frame 28. Therefore, since the light emitted from the LED chip 1 in the horizontal direction is emitted to the outside without being blocked by the positioning frame 28, the light extraction efficiency to the outside as the entire light emitting device can be improved. Further, in the light emitting device of the present embodiment, since the mount portion 25 protrudes from the plane, even if there is a gap in the adhesion portion between the color conversion member 4 and the mounting substrate 2 when the positioning frame 28 is not used. The blue light from the LED chip 1 can be prevented from leaking.

(Embodiment 5)
The basic configuration of the light emitting device of the present embodiment is substantially the same as that of the third embodiment. As shown in FIG. 5, the metal plate 25 has a predetermined length from the plane including the other surface of the insulating substrate 21 (for example, The difference is that it protrudes by 0.1 mm). In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 3, and description is abbreviate | omitted.

  In the light emitting device of this embodiment, as described above, the metal plate 25 protrudes by 0.1 mm from the plane including the other surface of the insulating substrate 21, and the thickness of the portion immediately below the metal plate 25 in the joint portion 84. Is about 20 μm, and the thickness of the portion directly below the external connection electrode 22b in the joint 83 is about 120 μm.

  Here, when the material of the metal plate 25 is Cu and the material of the metal plate 71 of the wiring board 7 is Al, the linear expansion coefficient of Cu is 17 ppm / ° C., and the linear expansion coefficient of Al is 23 ppm / ° C. 25 and the metal plate 71 have a small difference in linear expansion coefficient, so that even if the portion immediately below the metal plate 25 in the joint 84 is thin, cracks are unlikely to occur.

  On the other hand, regarding the portion immediately below the external connection electrode 22b in the joint 83, when the material of the insulating substrate 21 is alumina, the linear expansion coefficient of alumina is 7.5 ppm / ° C., so the insulating substrate 21 and the metal plate 71 has a large difference in linear expansion coefficient, and stress is generated in the joint 83 due to the difference in linear expansion coefficient between the metal plate 71 of the wiring substrate 7 and the insulating substrate 21 when a temperature cycle is applied due to energization on / off. As a result, cracks may occur in the joint 83.

  However, in the light emitting device of the present embodiment, the metal plate 25 protrudes by 0.1 mm from the plane including the other surface of the insulating substrate 21, and the thickness of the portion immediately below the external connection electrode 22 b in the joint 83. Is as thick as 120 μm, the stress generated in the joint 83 due to the difference in linear expansion coefficient between the metal plate 71 of the wiring board 7 and the insulating substrate 21 when the temperature cycle is applied by turning on / off the current is reduced (bonding). The stress strain per unit thickness of the portion 83 is alleviated), the occurrence of cracks can be suppressed, and the reliability with respect to the temperature cycle (the durability of the joint portion 83) is improved.

  In the light emitting device according to the present embodiment, as in the light emitting device according to the fourth embodiment shown in FIG. 4, the mount portion 25 protrudes from the plane including the one surface of the insulating substrate 21 or the positioning frame 28. May be provided.

(Embodiment 6)
The basic configuration of the light emitting device of the present embodiment is substantially the same as that of the fifth embodiment. As shown in FIGS. 6 and 7, the other surface side of the metal plate 25 (that is, the other surface side of the insulating substrate 21). On the same surface side, a plurality of grooves 25d that increase in width from the center toward the outside are formed radially, and the mounting region is arranged around the mounting region of the LED chip 1 in the mounting portion 25b of the metal plate 25. The difference is that a bonding material reservoir groove 25c is formed so as to surround it. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 5, and description is abbreviate | omitted.

  Here, each groove 25d has a width dimension gradually increasing from the center of the other surface of the metal plate 25 to the outside, and a depth dimension gradually increasing.

  By the way, in the configuration in which the metal plate 25 of the mounting board 2 is joined to the conductor pattern 74 of the wiring board 7 by the joining portion 84 made of solder as in each of the first to fifth embodiments, the other surface of the metal plate 25 is flat. Since the area is considerably larger than that of the external connection electrode 22b, there is a possibility that voids are generated in the joint portion 84 due to flux or bubbles generated in the process of melting and hardening of the solder. If there is, a crack occurs in the joint 84 due to a change in the stress caused by the difference in linear expansion coefficient between the mounting board 2 and the wiring board 7 when the temperature cycle is applied. There are things to do.

  On the other hand, in the light emitting device according to the present embodiment, since the groove 25d that is wider from the center toward the outside is formed on the other surface side of the metal plate 25, the light emitting device is mounted on the wiring board 7. 7B, when the metal plate 25 is joined to the conductor pattern 74 of the wiring board 7 by the solder 84a as shown in FIG. 7B, a gas such as a flux generated in the process of melting from the solder 84a (FIG. 7B). (Not shown) and bubbles 86 can easily escape to the outside along the groove 25d, and it is possible to suppress the formation of voids in the joint portion 84 made of the cured solder 84a and to obtain a good thermal coupling state. As a result, variation in thermal resistance between the LED chip 1 and the wiring board 7 can be reduced, and when the temperature cycle is applied, the mounting board 2 and the wiring board can be reduced. Resistance of the joint portion 84 to stress changes caused by the difference in linear expansion coefficient between the 7 becomes to be improved reliably.

  Further, in the light emitting device of this embodiment, as described above, the bonding material reservoir groove 25c is formed around the mounting region of the LED chip 1 in the mount portion 25b of the metal plate 25, so that FIG. , (C), when the LED chip 1 is bonded to the mounting region of the mount portion 25b by the bonding portion 12 made of solder (for example, solder having a high melting point such as AuSn), the LED chip 1 overflows from directly below the LED chip 1. Since the excess solder 12c accumulates in the bonding material reservoir groove 25c, it is possible to prevent a short circuit due to the excess solder 12c flowing out onto the wiring pattern 21 on the one surface side of the insulating substrate 21, and wire bonding. It is possible to prevent wire bonding defects that cannot be performed.

  In the light emitting device according to the present embodiment, as in the light emitting device according to the fourth embodiment shown in FIG. 4, the mount portion 25 protrudes from the plane including the one surface of the insulating substrate 21 or the positioning frame 28. May be provided. In other embodiments 1 to 5, a plurality of grooves 25d described in the present embodiment may be formed on the other surface of the metal plate 25. In other embodiments 3 to 5, the bonding material reservoir groove 25c described in the present embodiment may be provided around the mounting area of the LED chip 1 in the mount portion 25b.

  By the way, in each of the above-described first to sixth embodiments, a blue LED chip that emits blue light is adopted as the LED chip 1, but the LED chip 1 is not limited to one that emits blue light, for example, ultraviolet light. The emission color of the phosphor in the color conversion member 4 is not particularly limited.

The state which mounted the light-emitting device of Embodiment 1 on the wiring board is shown, (a) is a schematic plan view, (b) is AB schematic sectional drawing of (a). The state which mounted the light-emitting device of Embodiment 2 on the wiring board is shown, (a) is a schematic plan view, (b) is A-A 'schematic sectional drawing of (a). The state which mounted the light-emitting device of Embodiment 3 on the wiring board is shown, (a) is a schematic plan view, (b) is A-A 'schematic sectional drawing of (a). The state which mounted the light-emitting device of Embodiment 4 on the wiring board is shown, (a) is a schematic plan view, (b) is A-A 'schematic sectional drawing of (a). The state which mounted the light-emitting device of Embodiment 5 in the wiring board is shown, (a) is a schematic plan view, (b) is A-A 'schematic sectional drawing of (a). The light-emitting device of Embodiment 6 is shown, (a) is a schematic sectional drawing of the state mounted in the wiring board, (b) is a principal part schematic plan view, (c) is a principal part schematic sectional drawing. The same as above, (a) is a schematic bottom view of a metal plate, (b) is an explanatory view of the main part. It is a schematic sectional drawing of the state which mounted the light-emitting device of the prior art example on the wiring board. It is explanatory drawing same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LED chip 2 Mounting board 4 Color conversion member 7 Wiring board 21 Insulating board 21a Notch part 22 Wiring pattern 22b Electrode for external connection 25 Metal plate 25b Mount part 25c Groove for joining material reservoir 25d Groove 73 Conductive pattern 74 Conductive pattern 83 Joining Part 84 Joint

Claims (3)

An LED chip, wherein L ED chip provided with and a mounted board mounted, the implementation substrate, the other surface side with the L ED chip electrically connected to the wiring pattern on one surface side is formed an insulating substrate where the external connection electrodes are formed across the bets, metal wherein embedded in the other surface side peripheral line in the projection view of the insulation substrate is positioned outside the peripheral line of the L ED chip and a plate, the insulation resistance becomes the part of the side surface of the substrate cutout portion for exposing the side surface of the main barrel plate is provided between the LED chip and the metal plate, the insulating A light emitting device having a thin portion of a substrate . The mounting board, the light emitting device according to claim 1, characterized in that protrudes from the plane containing the metal plate before Symbol other surface side of the surface of the external connection electrodes of the insulating substrate. The metal plate is the same side as the other surface side of the insulating substrate, from the center of claim 1 or claim 2, wherein the composed is formed becomes wider groove width toward the outside Light emitting device .

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