JP2008166081A - Lighting device, and lighting apparatus having lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a load accompanying lighting to a jointing portion of a semiconductor light-emitting element and a conductor to a bonding wire, and suppress deformation of a device board accompanying wire bonding. <P>SOLUTION: The lighting device 31 comprises a device board 1 of a rectangular shape, a plurality of semiconductor light-emitting elements 11, a plurality of conductors 8, a bonding wire 17, and a translucent sealing member 22. The device board 1 has a rear face 1b which serves as a heat radiating face. Stress relaxation grooves 1a which are open on the heat radiation face are installed extended in a direction crossing the longitudinal direction of the board 1. The light-emitting elements 11 are mounted on the board 1 corresponding to the stress relaxation grooves 1a and are arranged in longitudinal direction of the board 1. The conductors 8 are arranged alternately with each light-emitting element 11 on the board 1 corresponding to the stress relaxation grooves 1a to be in a row in longitudinal direction of the device board 1. The light-emitting elements 11 and the conductors 8 adjoining in longitudinal direction of the device board 1 are connected by the bonding wire. The bonding wire 17 and the light-emitting elements 11 are sealed by the sealing member 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an illuminating device that emits light by emitting light from a semiconductor light emitting element such as an LED (light emitting diode), and a luminaire including the illuminating device as a light source unit.

  Conventionally, in order to promote the heat radiation from the LED embedded in the translucent resin, stabilize the LED output and emission wavelength, improve the reliability as LED, and extend the life of the LED, A technique for providing a heat radiation groove on the back surface of a mounted substrate is known.

In this technology, a row of concave portions formed of a plurality of concave portions is formed in parallel on one surface of a substrate, and LEDs, which are light-emitting elements individually mounted on the concave portions, are provided on the other surface (back surface) of the substrate. Each of the LEDs is electrically connected to the wiring terminal through a through hole that reaches the back surface of the substrate from the bottom surface of the recess. On the back surface of the substrate, heat radiating grooves are formed in parallel with the recess rows, respectively, between the recess rows, and heat traps are fitted in these grooves. Thereby, the heat generated by the LED is released from the heat radiating groove to the heat pipe to obtain high heat radiating properties (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2006-19557 (paragraphs 0006, 0021-0048, FIGS. 1 to 7)

  Even if there is a device for promoting heat dissipation from the lit LED, the temperature of the substrate rises to some extent. Accordingly, the substrate may be warped so that the distance between the both ends in the longitudinal direction is convex toward the one surface side of the substrate. However, in Patent Document 1 that discloses a technique in which LEDs arranged in a direction orthogonal to the longitudinal direction of the substrate are electrically connected to each other on the back surface of the substrate, the substrate warps due to an increase in the substrate temperature. There is no disclosure as to how this warpage affects the electrical connection between LEDs.

  By the way, as a lighting device, in addition to the one described in Patent Document 1, a plurality of LEDs and conductors are alternately arranged in the longitudinal direction of the substrate, and these are electrically connected by a bonding wire extending in the longitudinal direction of the substrate. An illuminating device in which at least a bonding wire and an LED are sealed with a translucent resin has been proposed by the present inventors.

  In such an illuminating device, the free deformation of the bonding wire is hindered by the resin filling the wire. Therefore, when the LED is turned on and the substrate is warped as the substrate temperature rises, a load is easily applied to the bonding portion of the bonding wire to the LED and the conductor, which may cause a lighting failure of the LED. It is done.

  For wire bonding, the bonding tool is pressed against the electrodes and conductors of the LED with a certain amount of pressing force, and it is necessary to consider that the substrate does not deform with the pressing force. . However, such consideration is not known in the technology in which the LED and the conductor are electrically connected via a bonding wire. At the same time, the technique of Patent Document 1 that does not electrically connect adjacent LEDs using a bonding wire does not suggest the consideration.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a lighting device capable of reducing a load caused by lighting on a joint portion between a semiconductor light emitting element and a conductor and a bonding wire, and capable of suppressing deformation of a device substrate caused by wire bonding, and a lighting fixture including the lighting device. Is to provide.

  The illumination device of the invention according to claim 1 has a long rectangular shape, a back surface forming a heat radiating surface, and a plurality of stress relaxation grooves extending in a direction intersecting a longitudinal direction of the long rectangular shape. A device substrate provided open to the surface; a plurality of semiconductor light emitting elements mounted on the device substrate corresponding to the stress relaxation grooves and arranged in a longitudinal direction of the device substrate; and corresponding between the stress relaxation grooves A plurality of conductors alternately arranged on the device substrate and arranged in the longitudinal direction of the device substrate; and the semiconductor light emitting devices and the conductors adjacent to each other in the longitudinal direction of the device substrate. A bonding wire connected; and a translucent sealing member that seals the bonding wire and the semiconductor light emitting element.

  In the first aspect of the present invention, a synthetic resin substrate, a metal-based substrate, or the like can be used as the device substrate. An example of the synthetic resin substrate is a glass epoxy substrate. The metal-based substrate is a substrate obtained by laminating an insulating layer made of a synthetic resin on one surface of a metal base made of Cu (copper), Al (aluminum), an alloy thereof, or the like. The insulating layer forming the surface of the metal-based substrate and the surface of the synthetic resin substrate should have high light reflection performance and exhibit white color in order to suppress the absorption of light inserted from the semiconductor issuing element and increase the light extraction efficiency. It is preferable.

  In the invention of claim 1, the shape of the cross section of the stress relaxation groove may be any shape such as a semicircular shape, a U shape, a V shape, and a trapezoidal shape. Further, the stress relaxation grooves intersecting with the longitudinal direction of the device substrate may be provided so as to intersect with the longitudinal direction of the device substrate at an angle as close as possible to this angle including the intersection angle of 90 degrees at the maximum. Furthermore, the stress relaxation grooves extending across the longitudinal direction of the device substrate are not limited to being continuously extended, and may be discontinuous.

  In the invention of claim 1, for example, a blue LED that emits blue light, an ultraviolet LED that emits ultraviolet light, or the like can be suitably used as the semiconductor light emitting element, but at least two of blue LEDs, red LEDs, and green LEDs can be used. It is also possible to use various types of LEDs in combination. And, for example, in the case of an illumination device that emits white light using a blue LED as a light source, a sealing member mixed with a phosphor that absorbs blue light and emits yellow light may be used. Alternatively, a phosphor that absorbs ultraviolet light and emits red light, a phosphor that absorbs ultraviolet light and emits green light, and a phosphor that absorbs ultraviolet light and emits yellow light are mixed. A sealing member may be used.

  In the invention of claim 1, a translucent sealing member that blocks the semiconductor light emitting element from the outside air and moisture to prevent the lifetime of the element from being reduced includes a translucent synthetic resin such as an epoxy resin, a silicone resin, and urethane. Resin or the like can be used, and transparent low melting point glass can also be used.

  The lighting device according to the first aspect of the present invention emits light from the semiconductor light-emitting element by energizing the semiconductor light-emitting element through the conductor and the bonding wire, transmits the light through the sealing member, and takes it out to the outside. Illuminate. With this lighting, the temperature of the device substrate rises, but the expansion of the inter-groove substrate portion located between adjacent stress relaxation grooves is absorbed by the stress relaxation groove, so that the device substrate is prevented from warping due to the thermal expansion. it can. For this reason, it is possible to reduce the load applied to the joint portion between the conductor and the semiconductor light emitting element and the bonding wire in accordance with the thermal expansion of the device substrate.

  Further, the substrate portion where the stress relaxation groove of the device substrate is formed becomes thin and its strength is reduced, but the other substrate portion between the grooves has a sufficient thickness and the strength is not lowered. Since the bonding wire is bonded to the conductor provided corresponding to the inter-groove substrate portion where the strength is maintained by wire bonding, the device substrate is deformed due to the stress relaxation groove along with the wire bonding to the conductor. There is no fear of doing. Further, since the thickness of the semiconductor light emitting element mounted on the substrate portion thinned by the stress relaxation groove is taken into account, the device substrate is deformed due to the stress relaxation groove along with the wire bonding to the semiconductor light emitting element. There is no fear.

  The illuminating device of the invention of claim 2 is characterized in that the stress relaxation groove is obliquely intersected with the longitudinal direction of the device substrate.

  In this invention, each stress relaxation groove is obliquely intersected with the longitudinal direction of the device substrate, and the inter-groove substrate portion where the strength between adjacent stress relaxation grooves does not decrease is interrupted by the stress relaxation groove in the longitudinal direction of the device substrate. Since the stress relaxation grooves are provided orthogonal to the longitudinal direction of the device substrate, the device substrate can be more effectively suppressed from being warped with lighting.

  The lighting apparatus of the invention of claim 3 comprises the lighting device according to claim 1 or 2 forming a light source part: a heat exhausting member disposed so as to overlap with a heat radiating surface of a device substrate provided in the lighting device; And a heat transfer member that fills each stress relaxation groove of the device substrate and carries out heat transfer between the device substrate and the exhaust heat member.

  Since this invention is provided with the illuminating device of Claim 1 or 2, while reducing the load accompanying the lighting with respect to the junction part of a semiconductor light emitting element and a conductor, and a bonding wire, the deformation | transformation of the board | substrate accompanying wire bonding can be reduced. Can be suppressed. In addition, the heat generated by the semiconductor light emitting element during lighting is released to the heat exhausting member from the stress relaxation groove at a position corresponding to the element, but the stress relaxation groove does not become a heat insulating space, and the heat transmitted through the groove is filled. Since heat can be smoothly conducted to the exhaust heat member through the heat member and released, temperature rise of the semiconductor light emitting element and the device substrate can be effectively suppressed.

  According to the first to third aspects of the present invention, it is possible to reduce a load associated with lighting of a semiconductor light emitting element and a joint between a conductor and a bonding wire, and to suppress deformation of the device substrate associated with wire bonding, and the illumination device Can be provided.

  A first embodiment of the present invention will be described with reference to FIGS.

  Reference numeral 30 in FIGS. 1 and 2 denotes an illumination device that forms an LED package. The lighting device 30 is used as a light source unit of a lighting fixture 31 (see FIG. 2). The illuminating device 30 is built in a fixture main body (not shown) provided in the luminaire 31 so as to face the irradiation opening, and illuminates the illumination target through the irradiation opening when turned on. The luminaire 31 includes a heat exhaust member 32 shown by a two-dot chain line in FIG. The heat exhausting member 32 receives heat released from the lighting device 30 and is composed of, for example, a heat sink.

  The illumination device 30 includes the device substrate 1, a plurality of conductors 8, a plurality of chip LEDs, for example, semiconductor light emitting elements 11, bonding wires 17 and 18, a reflector 20, and a sealing member 22. ing.

  The device substrate 1 has a long rectangular shape with a predetermined size in order to obtain a light emitting area required for the lighting device 30. The device substrate 1 is composed of a metal-based substrate in which an insulating layer 5 is laminated on one surface of a metal base 2. The metal base 2 is made of Cu.

  The thickness of the substrate main portion 2a other than the element mounting portion 3 described later of the metal base 2 is, for example, 0.25 mm. The back surface 1 b of the device substrate 1 made of the back surface of the metal base 2, that is, the surface on which a semiconductor light emitting element 11 described later is not mounted is used as a heat transfer surface that is in surface contact with the heat exhaust member 32.

  A plurality of stress relaxation grooves 1a are provided in the device substrate 1 so as to open on the back surface 1b. As shown in FIG. 4, the stress relaxation grooves 1 a are parallel to each other and extend, for example, in a direction orthogonal to the longitudinal direction of the device substrate 1. The arrangement pitch of the stress relaxation grooves 1a is equal to the arrangement pitch of the semiconductor light emitting elements 11 mounted side by side in the longitudinal direction of the device substrate 1. As representatively shown in FIG. 2, each stress relaxation groove 1 a has a cross-section in a direction perpendicular to the extending direction thereof, which is gradually opened toward the back surface 1 b of the device substrate 1, for example, a V shape. It is provided so as to cover the back side portion of the element mounting portion 3 to be operated. The opening width of the stress relaxation groove 1a is smaller than the diameter of the tip surface 3a of the element mounting portion 3 described later.

  Between the back surface 1b of the apparatus substrate 1 and the exhaust heat member 32 disposed in contact therewith, a heat transfer member 33 (see FIG. 2) responsible for heat transfer therebetween is provided. The heat transfer member 33 is mainly composed of, for example, a silicone resin, and is filled in the stress relaxation groove 1a.

  The metal base 2 has, for example, the same number of element mounting portions 3 formed by convex portions integrated with the metal base 2 as the number of semiconductor light emitting elements 11. These element mounting portions 3 are positioned directly above each stress relaxation groove 1a (in FIGS. 2 and 3) and project from the surface (one surface) of the substrate main portion 2a. As representatively shown in FIG. 2, the tip surface 3a of the element mounting portion 3 forms a flat surface parallel to the one surface, and the semiconductor light emitting element 11 is mounted on the tip surface 3a. Accordingly, the respective semiconductor light emitting elements 11 are mounted on the surface side of the device substrate 1 corresponding to the positions where the stress relaxation grooves 1 a are formed, and are arranged at intervals in the longitudinal direction of the device substrate 1.

  The present invention is not limited to mounting one semiconductor light emitting element 11 on the element mounting portion 3, and a plurality of semiconductor light emitting elements 11 can be mounted side by side on one element mounting portion 3. . In that case, it may be a plurality of semiconductor light emitting elements 11 that emit the same color or a plurality of semiconductor light emitting elements 11 that emit different colors. When attaching to the two element attaching portions 3, three semiconductor light emitting elements 11 emitting red, yellow, and blue light can be attached side by side. In the configuration in which a plurality of semiconductor light emitting elements 11 are mounted side by side on one element mounting portion 3, the total luminous flux of the lighting device 30 can be improved.

  The element mounting portion 3 is gradually formed thicker from the tip end surface 3a to one surface of the metal base 2. In other words, the element mounting portion 3 is formed in a truncated cone shape whose cross-sectional area perpendicular to the height direction gradually increases from the tip surface 3 a to the surface of the metal base 2. For this reason, the peripheral surface of the base portion forming the maximum diameter of the element mounting portion 3 forms an arc shape without forming a corner with the substrate main portion 2a and continues to the surface of the substrate main portion 2a. The light reflecting layer 4 is attached to the front end surface 3 a of the surface element mounting portion 3. The light reflecting layer 4 is made of an Ag thin film and has a thickness of 0.003 mm to 0.005 mm. At the same time, the reflectance of the Ag light reflecting layer 4 is 90% or more.

  If the height of the element mounting portion 3 including the light reflection layer 4 satisfies that the height position of the upper surface of the semiconductor light emitting element 11 in FIG. 2 is equal to or higher than the height position of the conductor 8 described later, the substrate main portion 2a. However, the height is preferably equal to or higher than the thickness of the substrate main portion 2a. In this embodiment, the thickness is higher than the total thickness of the insulating layer 5 and the conductor 8.

  For example, a white glass epoxy substrate is used for the insulating layer 5 in order to obtain light reflection performance. The thickness of the insulating layer 5 may be 0.060 mm at the minimum, and is set to, for example, 0.25 mm in this embodiment. The insulating layer 5 has an escape hole 6 through which the element mounting portion 3 passes, as representatively shown in FIGS. 2 and 3. The escape hole 6 is circular, for example, and the diameter thereof is larger than the diameter of the root portion forming the maximum diameter of the element mounting portion 3. The same number of escape holes 6 as the element mounting portions 3 are provided.

  The insulating layer 5 is laminated on the metal base 2 by being bonded to the surface (one surface) of the substrate main portion 2a using an adhesive 7. The adhesive 7 is insulative and is provided with a film thickness of, for example, 0.005 mm or less between the insulating layer 5 and the substrate main portion 2a. In adhesion of the insulating layer 5, each escape hole 6 of the insulating layer 5 is fitted into each element mounting portion 3, so that the insulating layer 5 is laminated on the metal base 2 except for the element mounting portion 3, thereby The attachment portion 3 is exposed in the escape hole 6.

  Since the insulating layer 5 does not hit the element mounting portion 3 by the fitting, the insulating layer 5 does not float with respect to the metal base 2 and is properly overlapped, and the insulating layer 5 is positioned with respect to the metal base 2. Is done. In other words, when the insulating layer 5 is bonded to the metal base 2 by the escape hole 6 of the insulating layer 5 through which the element mounting portion 3 made of a convex portion passes, the insulating layer 5 is prevented from hitting the element mounting portion 3. The insulating layer 5 can be appropriately laminated on the metal base 2.

And when the application amount of the adhesive 7 is large in the bonding, a part of the surplus 7a (see FIGS. 2 and 3) flows into the escape hole 6, and more precisely, the element mounting Due to the shape of the portion 3, the surplus portion 7 a flows into the annular gap inevitably formed between the peripheral surface of the element mounting portion 3 and the escape hole 6, and is accumulated and solidified there. The As a result, the insulating layer 5 is also bonded to the peripheral surface of the element mounting portion 3, so that the lamination strength is increased. Moreover, since the surplus portion 7a functions as an insulating layer having a volume resistivity of 10 ⁻² to 10 ⁻¹⁵ Ω · m, the insulating layer 5 on which the conductor 8 is mounted and the peripheral surface of the element mounting portion 3 as described later Withstand voltage between the two can be improved.

  The plurality of conductors 8 are provided to connect the semiconductor light emitting elements 11 in series as current-carrying elements to the semiconductor light emitting elements 11, and are opposite to the back surface bonded to the substrate main portion 2a of the insulating layer 5. It is formed by an etching process or the like. These conductors 8 are made of Cu, and are provided before the insulating layer 5 is bonded to the substrate main portion 2a.

  As shown in FIG. 1 and FIG. 3, each conductor 8 is disposed corresponding to a position deviated from the stress relaxation groove 1a when the device substrate 1 is viewed in plan, that is, between the stress relaxation grooves 1a. Two rows are formed at predetermined intervals in the longitudinal direction of the substrate 1. The plurality of conductors 8 in each row are alternately arranged with the escape holes 6 at a pitch of 4 mm, for example. An electric wire connecting portion 9 is integrally and continuously formed on the conductor 8 located on one end side of the row. Each of these electric wire connecting portions 9 is individually soldered with electric wires leading to a power source (not shown).

  As representatively shown in FIGS. 2 and 3, each conductor 8 does not reach the edge of the escape hole 6 but is separated from the edge of the escape hole 6 by a predetermined distance. Thereby, a part of the white insulating layer 5 is exposed between the end 8a of the conductor 8 and the edge of the escape hole 6 closest to the end 8a. Note that the exposed surface is indicated by reference numeral 5a. Therefore, an insulation distance larger than the annular gap can be secured between the end 8a of the conductor 8 and the element mounting portion 3, and light incident thereon can be reflected in the light extraction direction even on the exposed surface 5a.

  The end 8a of the conductor 8 is located at a distance of 0.25 mm to 6.0 mm from an electrode 14 or 15 described later of the semiconductor light emitting element 11. This is because, in the wire bonding described later, the end 8a of the conductor 8 is recognized by the bonding machine, and the bonding wire is bonded to a position separated by a predetermined distance E with reference to the end 8a. This is a consideration for suppressing the residual stress at the joint as much as possible.

  An Ag light reflecting layer 10 is deposited on the surface of each conductor 8. The light reflecting layer 10 is made of an Ag thin film having a reflectance of 90% or more, and has a thickness of 0.003 mm to 0.005 mm. The thickness of the conductor 8 including the light reflection layer 10 is 0.012 mm to 0.018 mm. Both the light reflecting layer 10 on each conductor 8 and the light reflecting layer 4 of each element mounting portion 3 can be provided at a time by, for example, plating. In this case, since the conductor 8 and the element mounting portion 3 are made of Cu, the light reflecting layers 10 and 4 can be provided by plating without plating them.

  Each semiconductor light emitting element 11 is made of, for example, a blue LED having a chip shape. The blue LED is a double wire type using, for example, a nitride semiconductor, and is formed by laminating a semiconductor light emitting layer 13 on one surface of a light-transmitting element substrate 12 as shown in FIG. The element substrate 12 is made of, for example, a sapphire substrate. The semiconductor light emitting layer 13 is formed by sequentially stacking a buffer layer, an n-type semiconductor layer, a light emitting layer, a p-type cladding layer, and a p-type semiconductor layer on the back surface of the element substrate 12. The light emitting layer has a quantum well structure in which barrier layers and well layers are alternately stacked. An n-side electrode 14 is provided on the n-type semiconductor layer, and a p-side electrode 15 is provided on the p-type semiconductor layer. The semiconductor light emitting layer 13 does not have a reflective film, and can emit light in both the thickness direction of the semiconductor light emitting element 11 and can also emit light from the side surface of the element substrate 12 to the side.

  These semiconductor light emitting elements 11 are die-bonded to the front end surface 3a of each element mounting portion 3 on the other surface parallel to the one surface of the element substrate 12 using a die bond material 16 made of an adhesive such as a translucent silicone resin. Yes. Accordingly, the respective semiconductor light emitting elements 11 are arranged alternately with these conductors 8 at a pitch of 4 mm, for example, like the respective conductors 8.

  The thickness of the die bond material 16 is 0.10 mm or less. The die bond material 16 serves as a resistance member for heat transfer from the semiconductor light emitting element 11 to the element mounting portion 3. However, since the die bond material 16 is extremely thin as described above, the thermal resistance of the die bond material 16 is substantially negligible. Therefore, it is desirable that the thickness of the die bond material 16 be as thin as possible without losing the bonding performance.

  The withstand voltage between the semiconductor light emitting layer 13 of the semiconductor light emitting element 11 and the element mounting portion 3 is secured not only by the die bond material 16 but also by the element substrate 12 made of sapphire much thicker than the die bond material 16. The thickness of the semiconductor light emitting element 11 including the die bond material 16 is, for example, 0.09 mm. By using such a semiconductor light emitting element 11, the height position of the semiconductor light emitting layer 13 is positioned higher than the light reflecting layer 10 on the surface of the conductor 8, and in the present embodiment, the entire semiconductor light emitting element 11 is on the surface of the conductor 8. It is positioned higher than the light reflecting layer 10.

  Due to the difference in height, in wire bonding described later, one end of the bonding wire is bonded to the electrodes 14 and 15 of the semiconductor light emitting layer 13 by ball bonding in a bonding machine, and the other end of the bonding wire is bonded to the conductor 8. At this time, the insulating layer 5 does not easily interfere with the movement of the bonding tool of the bonding machine, and the bonding wire is not forcibly pulled downward, so that wire bonding is easy.

  Furthermore, in a preferred configuration in which the entire semiconductor light emitting element 11 is disposed at a position higher than the surface of the insulating layer 5 as in the present embodiment, light emitted from the semiconductor light emitting element 11 to the periphery thereof is applied to the insulating layer 5. It is easy to insert into the periphery of the escape hole 6 without being obstructed. Thereby, the light can be extracted by reflecting the light around the semiconductor light emitting element 11, which is advantageous in that the light extraction efficiency can be increased.

  The conductors 8 and the semiconductor light emitting elements 11 arranged alternately in the longitudinal direction of the metal base 2 are connected by bonding wires 17 provided by wire bonding. As shown in FIG. 1, the bonding wires 17 are arranged extending in the longitudinal direction of the device substrate 1 when the device substrate 1 is viewed from the front. Further, the conductors 8 positioned on the other end side of the two conductor rows are connected by an end bonding wire 18 provided by wire bonding as shown in FIG. Accordingly, in the present embodiment, the semiconductor light emitting elements 11 are electrically connected in series.

  The planar light source of the lighting device 30 is formed by the device substrate 1 having the light reflecting layer 4, the conductor 8 having the light reflecting layer 10, the semiconductor light emitting element 11, the bonding wire 17, and the end bonding wire 18. Has been.

  The reflector 20 is not individually provided for each one or several semiconductor light emitting elements 11, but is a single one surrounding all the semiconductor light emitting elements 11 on the insulating layer 5. As shown in FIG. 2, it is formed of a rectangular frame. The reflector 20 is bonded to the insulating layer 5. A part of the wire connecting portion 9 is located outside the reflector 20 in order to connect the wire. The inner peripheral surface of the reflector 20 is a light reflecting surface. Therefore, for example, white powder such as aluminum oxide is mixed in a synthetic resin that is a molding material of the reflector 20. The reflector 20 can use the light extracted in the light extraction direction as an attachment portion of a light distribution control member (not shown) such as a lens that controls the projection target.

  The sealing member 22 seals the semiconductor light emitting element 11, the pair of bonding wires 17 connected thereto, and the ends of the conductors 8 connected to the bonding wires 17. The sealing member 22 is supplied by dropping (potting) in an uncured state from a dispenser (not shown), and is cured by exhibiting a shape that rises in a substantially hemispherical shape after dropping. Providing the sealing member 22 by potting as described above is preferable in that the amount of the sealing member 22 used can be reduced, and the reflector 20 may be omitted in the configuration in which the sealing member 22 is provided as described above. . However, the sealing member 22 can be provided by filling most of the portions located in the reflector 20 by being injected into the reflector 20 and solidified.

  The sealing member 22 is made of a translucent material such as a transparent silicone resin, and a phosphor is mixed therein if necessary. In the present embodiment, since the semiconductor light emitting element 11 emits blue light, phosphors (not shown) that absorb this light and emit yellow light are preferably mixed in a substantially uniformly dispersed state.

  By this combination, a part of blue light emitted from the semiconductor light emitting layer 13 by lighting of the lighting device 30 passes through the sealing member 22 without hitting the phosphor, while the phosphor hit by the blue light is The blue light is absorbed to emit yellow light, and the yellow light passes through the sealing member 22. Therefore, the white light of the illumination device 30 can be irradiated by mixing these two colors having a complementary color relationship. Since the reflector 20 has a frame shape, most of the light extracted from the illumination device 30 is transmitted through the sealing member 22 without being reflected by the reflector 20, so that the loss of light due to reflection is small. It is also effective in improving the light extraction efficiency.

  The illuminating device 30 having the above configuration performs illumination by extracting light in the direction of the arrow in FIG. 2 by energizing each semiconductor light emitting element 11 and causing the semiconductor light emitting elements 11 to emit light. As each semiconductor light emitting element 11 generates heat during lighting, the temperature of the device substrate 1 rises and the device substrate 1 expands accordingly.

  However, since the device substrate 1 is formed with a plurality of stress relaxation grooves 1a that extend across the longitudinal direction of the device substrate 1 and open on the back surface 1b of the device substrate 1, the device substrate 1 is optically coupled with the thermal expansion. It can suppress warping so that it may become convex on the outgoing side. That is, since the inter-groove substrate part between the adjacent stress relaxation grooves 1a is configured to be divided by the stress relaxation groove 1a, the thermal expansion of each of the inter-groove substrate parts is caused between the adjacent grooves. It can be absorbed by the stress relaxation groove 1a to spread to the substrate portion. Such stress absorption suppresses warpage of the device substrate 1 due to thermal expansion. Therefore, since the load given to the bonding portion of the conductor 8 and the semiconductor light emitting element 11 and the bonding wire 17 arranged in a line in the longitudinal direction of the device substrate 1 due to the thermal expansion of the device substrate 1 is reduced, the bonding failure Thus, it is possible to prevent the semiconductor light emitting element 11 from being turned on.

  In the illuminating device 30 having the above-described configuration, the portion of the device substrate 1 where the stress relaxation groove 1a is formed is thinned and the strength is lowered, but the other substrate portion between the grooves is sufficiently thick and the strength is lowered. Absent. And the conductor 8 is provided corresponding to the board | substrate part between groove | channels in which this intensity | strength was maintained, and the bonding wire 17 is joined to this conductor 8 by wire bonding. For this reason, there is no fear that the apparatus substrate 1 is deformed due to the stress relaxation groove 1 a at a position corresponding to the conductor 8 along with the wire bonding to the conductor 8.

  Further, since the thickness of the semiconductor light emitting element 11 mounted on the portion of the device substrate 1 thinned by the stress relaxation groove 1a is taken into account, the semiconductor light emitting element 11 is accompanied by wire bonding to the semiconductor light emitting element 11. There is no possibility that the apparatus substrate 1 is deformed due to the stress relaxation groove 1a at a position corresponding to the above. Moreover, in the present embodiment, the portion where the semiconductor light emitting element 11 is attached by the convex element attaching portion 3 is thicker than the other portions, and the strength thereof does not decrease. Due to the stress relaxation groove 1a at the position, there is no possibility that the device substrate 1 is deformed along with the wire bonding.

  In the illumination device 30 having the configuration, the conductor 8 for guiding power to the semiconductor light emitting element 11 and the metal base 2 are electrically insulated by an insulating layer 5 provided therebetween. The insulating layer 5 is made of metal. While not interposed between the base 2 and the semiconductor light emitting element 11, the semiconductor light emitting element 11 is directly die-bonded to the element mounting portion 3 of the metal base 2.

  Therefore, the heat generated by each semiconductor light emitting element 11 is directly conducted to the metal base 2 without being disturbed by the insulating layer 5. More specifically, the heat of the semiconductor light-emitting element 11 passes through the die bonding material 16 that is so thin that it does not substantially become thermal resistance, and then is transmitted to the element mounting portion 3 of the metal base 2 through the Ag light reflecting layer 4. It is done. In addition, the element mounting portion 3 of the metal base 2 gradually becomes thicker from the tip surface 3a to which the semiconductor light emitting element 11 is die-bonded to the substrate main portion 2a of the metal base 2, in other words, the cross-sectional area of the element mounting portion 3 is the substrate. Since it becomes so large that it approaches the main part 2a, the heat conduction from the semiconductor light emitting element 11 toward the back surface 1b of the apparatus substrate 1 becomes easier. The heat of the metal base 2 is released to the outside from the back surface 1b.

  In this heat dissipation to the outside, each stress relaxation groove 1a is filled with a heat transfer member 33 responsible for heat transfer between the back surface 1b of the device substrate 1 and the exhaust heat member 32 disposed in contact therewith, Since the stress relaxation groove 1a does not become a heat insulating space, heat can be smoothly conducted to the heat exhausting member 32 through the heat transfer member 33 having high thermal conductivity to dissipate heat. Thereby, as the temperature rise of the semiconductor light emitting element 11 and the device substrate is effectively suppressed, deformation due to thermal expansion of the device substrate 1 can be more effectively suppressed.

  In this way, the heat of the semiconductor light emitting element 11 is released to the outside through the metal base 2 with high efficiency, so that the temperature rise of each semiconductor light emitting element 11 is effectively suppressed, and the temperature of each semiconductor light emitting element 11 is set as designed. Can be maintained. Therefore, a decrease in the light emission efficiency of each semiconductor light emitting element 11 and a variation in the amount of light emitted from each semiconductor light emitting element 11 are suppressed, and as a result, color unevenness of light extracted from each semiconductor light emitting element can be suppressed.

  Each of the semiconductor light emitting elements 11 having the above-described structure emits light in all directions, and in particular, the back direction, that is, the metal base 2 rather than the light emitted in the front direction, that is, the light extraction direction opposite to the metal base 2. The light emitted toward is stronger.

  Then, most of the light emitted in the reverse direction passes through the translucent die-bonding material 16 and enters the light reflecting layer 4 made of an Ag plating layer having a light reflectance of 90% or more, and this light reflecting layer. 4 is reflected in the light extraction direction. Such high-efficiency reflection directly under the semiconductor light emitting element 11 can further improve the light extraction efficiency. Incidentally, as for the light having a wavelength of 460 nm, it is clear from the measurement results that the intensity of the extracted light (relative light emission intensity) increases as the reflectance directly below the semiconductor light emitting element 11 increases. It was confirmed that the direct reflectance was 91.35%.

  In addition, a part of the light emitted in the reverse direction and a part of the light emitted from the phosphor in the sealing member 22 enter the white insulating layer 5, and light is extracted by the insulating layer 5. Reflected in the direction. In addition, part of the light traveling in the back direction is incident on the light reflecting layer 10 made of an Ag plating layer covering the conductor 8 and reflected by the insulating layer 5 in the light extraction direction. Furthermore, the periphery of the escape hole 6 of the insulating layer 5 is not partially covered with the conductor 8, and has an exposed surface 5 a between the conductor 8 and the escape hole 6. In other words, since the periphery of the escape hole 6 can be regarded as a continuous white reflecting surface without interruption along the circumferential direction, the light incident thereon can be reflected in the light extraction direction. Incidentally, it becomes clear as a result of the measurement that the intensity (relative emission intensity) of the extracted light increases as the average reflectance of light having a wavelength of 400 nm to 740 nm increases, and the reflectance around the semiconductor light emitting element 11 is 93. It was confirmed to be 7%.

  The lower the reflectance is, the lower the luminous efficiency. In other words, the higher the reflectance is, the higher the luminous efficiency is. Therefore, the high reflection characteristics of the light reflecting layers 4 and 10 made of an Ag plating layer and the white insulating layer 5 The luminous efficiency (light extraction efficiency) of the lighting device 30 could be improved. Incidentally, as a result of the experiment, it was confirmed that when the power consumption of the illumination device 30 is 0.06 W, illumination can be performed with a luminous flux of 7.4 lm and a light emission efficiency of 125 lm / W.

  Therefore, the illumination device 30 having the above-described configuration has a high reflection characteristic of light emitted to the back side of each semiconductor light emitting element 11 while suppressing a decrease in light emission efficiency due to a temperature increase of each semiconductor light emitting element 11 due to high heat conduction. The light extraction efficiency can be improved.

  Further, since the die bonding material 16 obtained by die bonding the semiconductor light emitting element 11 to the element mounting portion 3 of the metal base 2 is a transparent silicone resin, the possibility that the die bonding material is deteriorated with discoloration is extremely small. Therefore, the extraction efficiency of the light reflected and extracted by the light reflecting layer 4 can be maintained over a long period of time.

  FIG. 5 shows a second embodiment of the present invention. Since the second embodiment is the same as the first embodiment except for the matters described below, including the matters not shown, the same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  In the second embodiment, the stress relaxation grooves 1 a are provided so as to cross obliquely rather than intersecting at right angles to the longitudinal direction of the device substrate 1. The configuration other than this point is the same as that of the first embodiment.

  Therefore, also in the illumination device 30 of the second embodiment, for the reason described in the first embodiment, the semiconductor light emitting elements 11 and the conductors 8 and the bonding wires 17 that are alternately arranged in a row in the longitudinal direction of the device substrate 1. It is possible to provide a lighting device 30 that can reduce the load caused by lighting on the joint portion of the device and can suppress the deformation of the device substrate 1 caused by wire bonding.

  In addition, since the stress relaxation grooves 1 a are obliquely intersected with the longitudinal direction of the device substrate 1, the inter-groove substrate portion where the strength between the adjacent stress relaxation grooves 1 a does not decrease is stress relaxation with respect to the longitudinal direction of the device substrate 1. It can be prevented from being interrupted by the groove 1a. Therefore, it is excellent in that the device substrate 1 can be more effectively suppressed from being warped with lighting than in the case where the stress relaxation groove 1a is provided perpendicular to the longitudinal direction of the device substrate 1 as in the first embodiment. ing.

The front view which abbreviate | omits and shows a part of sealing member which this apparatus has for the illuminating device which concerns on 1st Embodiment of this invention. Sectional drawing which expands and shows a part of illuminating device of FIG. The front view which shows the part shown by FIG. 2 in the state from which the sealing member was removed. The front view which shows the positional relationship of the stress relaxation groove with respect to arrangement | positioning of the semiconductor light-emitting element and conductor in the illuminating device of FIG. The front view which shows the positional relationship with the stress relaxation groove | channel with respect to arrangement | positioning of the semiconductor light-emitting element and conductor in the illuminating device which concerns on 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Device substrate, 1a ... Stress relaxation groove, 1b ... Back surface of device substrate, 8 ... Conductor, 11 ... Semiconductor light emitting element, 17 ... Bonding wire, 22 ... Sealing member, 30 ... Lighting fixture, 31 ... Lighting device, 32 ... Heat exhaust member, 33 ... Heat transfer member

Claims (3)

A device substrate having a long rectangular shape and having a back surface forming a heat dissipation surface, and a plurality of stress relaxation grooves extending in a direction intersecting a longitudinal direction of the long square shape and opened to the heat dissipation surface; ;
A plurality of semiconductor light emitting elements mounted on the device substrate corresponding to the stress relaxation grooves and arranged in the longitudinal direction of the device substrate;
A plurality of conductors arranged alternately with the semiconductor light emitting elements on the device substrate corresponding to the stress relaxation grooves and arranged in the longitudinal direction of the device substrate;
A bonding wire connecting the semiconductor light emitting element adjacent to the longitudinal direction of the device substrate and the conductor;
A translucent sealing member that seals the bonding wire and the semiconductor light emitting element;
An illumination device comprising:   The lighting device according to claim 1, wherein the stress relaxation grooves are crossed obliquely with respect to a longitudinal direction of the device substrate. The illumination device according to claim 1 or 2, which forms a light source unit:
An exhaust heat member disposed on the heat dissipation surface of the device substrate provided in the lighting device;
A heat transfer member that fills each stress relaxation groove of the device substrate to transfer heat between the device substrate and the exhaust heat member;
The lighting fixture characterized by comprising.

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