JP2007116129A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a stress applied to an LED chip due to difference in linear expansion coefficient. <P>SOLUTION: The light emitting device 1 comprises: an LED chip 10; and a mounting substrate 20 on which the LED chip 10 is mounted. The mounting substrate 20 comprises: a metal plate 21 for mounting the LED chip 10; and a wiring board 22 consisting of an insulating substrate 22a laminated on the part of the metal plate 21 not mounting the LED chip 10 and provided, on the surface opposite to the metal plate 21, with a lead pattern 23 connected electrically with the electrode of the LED chip 10. At the part of the metal plate 21 for mounting the LED chip 10, a submount member 30 formed of an insulating material having a linear expansion coefficient substantially identical to that of the material of the LED chip 10 is provided. The LED chip 10 is mounted on the metal plate 21 through the submount member 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  With the recent increase in output of LED chips, development of light-emitting devices that use LED chips for lighting purposes is underway (see, for example, Patent Document 1).

The light emitting device disclosed in the above-mentioned patent document is composed of a base material formed in a box shape with one surface opening by an inorganic material such as metal, and an airtight container forming material that is made of transparent glass or ceramic and closes the base material opening. A plurality of LED chips are distributed and mounted on the bottom wall of the base material, and light emitted from the LED chips is irradiated outside the hermetic container through the hermetic container forming material. .
JP 2004-119634 A

  In the light emitting device having the above configuration, since the LED chip is directly mounted on the bottom wall of the base material made of an inorganic material such as metal, it is caused by the difference in linear expansion coefficient between the LED chip material and the base material. There was a risk of stress being applied to the LED chip.

  The present invention has been made in view of the above problems, and an object thereof is to provide a light emitting device in which stress applied to an LED chip due to a difference in linear expansion coefficient is reduced.

  In order to achieve the above object, the invention of claim 1 is an LED chip, a mounting substrate on which the LED chip is mounted, and a light-transmitting material that is electrically connected to the LED chip and the electrode of the LED chip. A sealing portion for sealing the bonded wire, an optical member for controlling the light distribution of the emitted light from the LED chip that has passed through the sealing portion, and a material including at least a light-transmitting material. The LED chip is provided with a protective cover disposed on the mounting substrate so as to cover one of the anode electrode and the cathode electrode on one surface of the mounting substrate side, and the anode electrode or the cathode electrode on the other surface. The mounting substrate is made of a heat conductive material and is mounted on the heat transfer plate on which the LED chip is mounted and the LED chip non-mounting portion on the heat transfer plate. A lead pattern electrically connected to the electrode of the LED chip via a bonding wire and an insulating substrate formed on the surface opposite to the heat transfer plate, and the LED chip mounting portion on the heat transfer plate The LED chip is mounted on the heat transfer plate via the submount member, and the material of the submount member is either a conductor or a semiconductor and linearly expands with the LED chip material. The material is substantially the same rate, and one electrode of the LED chip is electrically connected to the submount member, and the submount member and the lead pattern are electrically connected via the bonding wire. To do.

  According to the present invention, the submount member formed of a material whose linear expansion coefficient is substantially the same as that of the LED chip material is disposed between the heat transfer plate and the LED chip. As a result, the stress applied to the LED chip can be reduced. Furthermore, since one electrode is formed on the surface of the LED chip on the mounting substrate side and the submount member is formed of either a conductor or a semiconductor, one electrode of the LED chip is connected to the submount member, By electrically connecting the submount member and the lead pattern via a bonding wire, the LED chip and the lead pattern can be electrically connected, and the submount member itself is part of the electric circuit. Therefore, it is not necessary to form an electrode pattern on the surface of the submount member, and the cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
Hereinafter, the light-emitting device of this embodiment will be described with reference to FIGS.

  The light emitting device 1 of the present embodiment includes an LED chip 10, a mounting substrate 20 on which the LED chip 10 is mounted, a frame body 40 that surrounds the LED chip 10 on the mounting surface side of the LED chip 10 on the mounting substrate 20, and a frame body The LED 40 and the bonding wires 14 and 14 connected to the LED chip 10 are formed by filling a transparent resin material on the inside of the LED 40 and have an elastic sealing part 50; The optical member 60 that controls the light distribution of the emitted light from the LED chip 10 that has passed through the lens-and-sealing portion 50 disposed in an overlapping manner, and the emission color of the LED chip 10 that is excited by the light emitted from the LED chip 10. A molded product obtained by molding a phosphor that emits light of a color different from that of the transparent material together with the transparent material, covering the optical member 60 on the light emitting surface 60b side of the optical member 60, and the light emitting surface 6 And a dome-shaped protective cover 70 disposed in the form of an air layer 80 is formed between the b and the frame body 40.

  The light emitting device 1 is used, for example, as a light source of a lighting fixture. For example, a resin sheet containing a filler made of a filler such as silica or alumina and having a low viscosity when heated (for example, an epoxy resin highly filled with fused silica) The LED chip 10 can be mounted on an instrument body 100 by mounting it on an instrument body 100 made of metal (for example, a metal having high thermal conductivity such as Al or Cu) through an insulating layer 90 formed of an organic green sheet such as a sheet. The heat resistance to the main body 100 is reduced, and the heat dissipation is improved. Therefore, since the temperature rise of the junction temperature of the LED chip 10 can be suppressed and the input power can be increased, the light output can be increased.

  The mounting substrate 20 includes a metal plate 21 (heat transfer plate) on which the LED chip 10 is mounted, and an insulating base material 22a such as a glass epoxy substrate stacked on a portion of the metal plate 21 where the LED chip 10 is not mounted. And a wiring board 22. A pair of lead patterns 23 that are electrically connected to both electrodes (anode electrode and cathode electrode) (not shown) of the LED chip 10 are formed on the surface of the insulating substrate 22a opposite to the metal plate 21. Further, a window hole 24 is provided in a portion corresponding to the LED chip 10 in the insulating base material 22a, and the LED chip 10 is mounted on the surface of the metal plate 21 exposed from the window hole 24 via a submount member 30 described later. Therefore, the heat generated in the LED chip 10 can be transferred to the metal plate 21 without passing through the insulating base material 22a. Here, although CuW is adopted as the material of the metal plate 21, any metal material having a relatively high thermal conductivity may be used, and not only CuW but also Al or the like may be adopted. The metal plate 21 and the insulating base material 22a are fixed by a fixing material 25 made of a sheet-like adhesive film having insulating properties. Each lead pattern 23 is formed of a laminated film of a Ni film and an Au film, and the portions inside the frame body 40 in the plan view become inner lead portions (bonding electrodes) 23 a and 23 a, and the protective cover 70. The portions not covered with the outer lead portions (connecting electrodes) 23b, 23b.

  The LED chip 10 is a GaN-based blue LED chip that emits blue light, and is a conductive substrate composed of an n-type SiC substrate having a lattice constant and a crystal structure close to GaN as a crystal growth substrate and having conductivity compared to a sapphire substrate. The light-emitting portion 12 is formed of a GaN-based compound semiconductor material on the main surface side of the conductive substrate 11 and formed of a laminated structure portion having a double hetero structure, for example, by an epitaxial growth method (for example, MOVPE method or the like). ), A cathode electrode (n electrode) which is a cathode side electrode (not shown) is formed on the back surface of the conductive substrate 11, and is shown on the surface of the light emitting unit 12 (the outermost surface on the main surface side of the conductive substrate 11). An anode electrode (p electrode) which is an electrode on the anode side that is not to be formed is formed. In short, the LED chip 10 has an anode electrode formed on one surface side and a cathode electrode formed on the other surface side. The cathode electrode and the anode electrode are composed of a laminated film of a Ni film and an Au film, but the material of the cathode electrode and the anode electrode is not particularly limited, and a material capable of obtaining good ohmic characteristics For example, Al or the like may be employed. In the present embodiment, the light emitting unit 12 of the LED chip 10 is mounted on the metal plate 21 so as to be on the side farther from the metal plate 21 than the conductive substrate 11. The conductive plate 11 may be mounted on the metal plate 21 so as to be closer to the metal plate 21 than the conductive substrate 11. In consideration of the light extraction efficiency, it is desirable to arrange the light emitting unit 12 on the side away from the metal plate 21, but in this embodiment, the conductive substrate 11 and the light emitting unit 12 have the same refractive index. Therefore, even if the light emitting unit 12 is disposed on the side close to the metal plate 21, the light extraction loss does not become too large.

The LED chip 10 is formed in a rectangular plate shape larger than the chip size of the LED chip 10, and the stress acting on the LED chip 10 due to the difference in linear expansion coefficient between the LED chip 10 and the metal plate 21 is applied. It is mounted on the metal plate 21 via a submount member 30 that relaxes. The submount member 30 has not only a function of relieving the stress, but also a heat conduction function of transferring heat generated in the LED chip 10 to a range wider than the chip size of the LED chip 10 on the metal plate 21. . The material of the submount member 30 is either a conductor or a semiconductor, and a material having a linear expansion coefficient substantially the same as that of the LED chip 10 and a relatively high thermal conductivity. Here, the linear expansion coefficient being substantially the same means a case where the linear expansion coefficient of the LED chip 10 is within a range of ± 3 × 10 ⁻⁶ / K when the linear expansion coefficient is the central value. Si (linear expansion coefficient 2.6 × 10 ⁻⁶ / K, thermal conductivity) having a linear expansion coefficient relatively close to that of SiC (linear expansion coefficient 4.2 × 10 ⁻⁶ / K), which is a material of 168 W / m · K).

  The material of the submount member 30 is not intended to be limited to a semiconductor material such as Si, but a conductor material or a semiconductor material having a linear expansion coefficient relatively close to that of the LED chip 10 and a relatively high thermal conductivity. Should be selected. In this embodiment, since the LED chip 10 is mounted on the submount member 30 with the conductive substrate 11 facing down (submount member 30 side), the material of the submount member 30 is the conductive substrate 11. A material substantially the same as the linear expansion coefficient of SiC, which is the material, is used. However, when the LED chip 10 is mounted on the submount member 30 with the light emitting portion 12 on the lower side (submount member 30 side), As the material of the mount member 30, a material having substantially the same linear expansion coefficient as that of the light emitting unit 12 may be used.

Here, in this embodiment, a blue LED chip whose emission color is blue is adopted as the LED chip 10 and a SiC substrate is adopted as the conductive substrate 11, but a GaN substrate may be used instead of the SiC substrate, When a SiC substrate or a GaN substrate is used, the crystal growth substrate has a higher thermal conductivity and a lower thermal resistance than the crystal growth substrate compared to the case where a sapphire substrate is used as the crystal growth substrate. it can. The light emission color of the LED chip 10 is not limited to blue, and may be red or green, for example. That is, the material of the light-emitting portion 12 of the LED chip 10 is not limited to the GaN-based compound semiconductor material, and a GaAs-based compound semiconductor material, a GaP-based compound semiconductor material, or the like may be employed according to the emission color of the LED chip 10. Further, the conductive substrate 11 is not limited to the SiC substrate, and may be appropriately selected from, for example, a GaAs substrate and a GsP substrate according to the material of the light emitting unit 12. Here, when GaN (linear expansion coefficient 5.59 × 10 ⁻⁶ / K) or GaAs (linear expansion coefficient 5.9 × 10 ⁻⁶ / K) is used as the material of the LED chip 10 (that is, the conductive substrate 11). In this case, CuW (linear expansion coefficient 6.4 × 10 ⁻⁶ / K, thermal conductivity 168 W / m · K) having a linear expansion coefficient relatively close to the linear expansion coefficient of these materials is used as the material of the submount member 30. When GaP (linear expansion coefficient 4.65 × 10 ⁻⁶ / K) is used as the material of the LED chip 10, the linear expansion coefficient is relatively close to W (linear expansion coefficient 4.5 × 10 ⁻⁶ / K, thermal conductivity 178 W / m · K) may be used as the material of the submount member 30.

  Further, the LED chip 10 is mounted on the surface of the submount member 30 (the surface opposite to the metal plate 21), and a metal thin wire (for example, a gold thin wire) is formed on the surface of the submount member 30 where the LED chip 10 is not mounted. And the other end of the bonding wire 14 is connected to one lead pattern 23 so that the cathode electrode of the LED chip 10 is connected to the submount member 30 and the bonding wire. 14 is electrically connected to one of the lead patterns 23. The anode electrode of the LED chip 10 is electrically connected to the other lead pattern 23 through the bonding wire 14. The LED chip 10 and the submount member 30 may be bonded using, for example, solder such as SnPb, AuSn, SnAgCu, or silver paste, but may be bonded using lead-free solder such as AuSn, SnAgCu. It is preferable. A reflective film (for example, a laminated film of a Ni film and an Ag film) that reflects light emitted from the LED chip 10 may be formed on the surface of the submount member 30 on the LED chip 10 side.

  Although the silicone resin is used as the transparent resin material of the sealing portion 50 described above, not only the silicone resin but also an acrylic resin may be used.

  On the other hand, the frame 40 has a cylindrical shape and is formed of a light-transmitting material such as silicone. In short, in the present embodiment, the frame body 40 is formed of a translucent material having a linear expansion coefficient equivalent to that of the sealing resin that is the material of the sealing portion 50. Here, in this embodiment, after the frame body 40 is fixed to the mounting substrate 20, the sealing resin 50 is filled (potted) inside the frame body 40 and thermally cured to form the sealing portion 50. is there. In the case where an acrylic resin is used as the sealing resin for the sealing portion 50 instead of the silicone resin, it is desirable to employ an acrylic resin as the translucent material for the frame body 40.

  The optical member 60 is composed of a biconvex lens in which each of the light incident surface 60a and the light emitting surface 60b on the sealing portion 50 side is formed in a convex curved surface shape. Here, the optical member 60 is formed of a molded product of silicone resin, and the refractive index is the same as that of the sealing portion 50. However, the optical member 60 is not limited to a molded product of silicone. You may comprise by the molded article of resin.

  By the way, the optical member 60 has a light exit surface 60b formed in a convex curved surface shape that does not totally reflect the light incident from the light incident surface 60a at the boundary between the light exit surface 60b and the air layer 80 described above. Here, the optical member 60 is disposed so that the optical axis of the optical member 60 is positioned on the center line of the light emitting unit 12 along the thickness direction of the LED chip 10. The light emitted from the side surface of the LED chip 10 propagates through the sealing portion 50 and the air layer 80 to reach the protective cover 70 and does not excite the phosphor of the protective cover 70 or collide with the phosphor. Or passing through the protective cover 70.

  The protective cover 70 is composed of a molded product of a mixture of a transparent material such as silicone and a particulate yellow phosphor that emits broad yellow light when excited by the blue light emitted from the LED chip 10. (That is, the protective cover 70 is formed of a translucent material and a phosphor). Therefore, in the light emitting device of this embodiment, the blue light emitted from the LED chip 10 and the light emitted from the yellow phosphor are emitted through the outer surface 70b of the protective cover 70, and white light can be obtained. . Note that the transparent material used as the material of the protective cover 70 is not limited to silicone, for example, an acrylic resin, epoxy resin, glass, an organic / inorganic hybrid material in which an organic component and an inorganic component are mixed and bonded at the nm level or molecular level, and the like. It may be adopted. The phosphor mixed with the transparent material used as the material of the protective cover 70 is not limited to the yellow phosphor. For example, white light can be obtained by mixing a red phosphor and a green phosphor. The protective cover 70 of this embodiment has a function for protecting the light emitting portion and a color conversion function. However, the protective cover 70 does not necessarily have a color conversion function, and is used only for the purpose of protection. Also good. In this case, the phosphor is unnecessary, and the protective cover 70 is formed only from the light-transmitting material.

  Here, the inner surface 70 a of the protective cover 70 is formed in a shape along the light emitting surface 60 b of the optical member 60. Therefore, the distance between the light emitting surface 60b and the inner surface 70a of the protective cover 70 in the normal direction is a substantially constant value regardless of the position of the light emitting surface 60b of the optical member 60. In addition, the protective cover 70 is shape | molded so that the thickness along a normal line direction may become uniform irrespective of a position. The protective cover 70 may be bonded to the mounting substrate 20 at the edge on the mounting substrate 20 side (periphery of the opening) using, for example, an adhesive (for example, silicone resin, epoxy resin). In addition, an air layer 80 is formed between the protective cover 70 and the optical member 60, and this air layer 80 functions as a heat insulating layer, so that heat generated in the phosphor of the protective cover 70 is transferred to the LED chip 10. Can be suppressed.

  As described above, in the light emitting device 1 of the present embodiment, the portion of the metal plate 21 where the LED chip 10 is mounted is either a conductor material or a semiconductor material, and the linear expansion coefficient is substantially the same as the material of the LED chip 10. A submount member 30 made of a material is provided. That is, since the submount member 30 formed of a material whose linear expansion coefficient is substantially the same as the material of the LED chip 10 is disposed between the metal plate 21 and the LED chip 10, the difference is caused by the difference in thermal expansion coefficient. The stress applied to the LED chip 10 can be reduced. Moreover, since the material with favorable heat conductivity is used as a material of the submount member 30, the heat dissipation of the LED chip 10 can be improved. Furthermore, one of the anode electrode and the cathode electrode is formed on the surface of the LED chip 10 on the mounting substrate 20 side, and the submount member 30 is formed of either a conductor or a semiconductor. The electrodes are electrically connected to the submount member 30, and the submount member 30 and the lead pattern 23 are electrically connected via the bonding wires 14, whereby the LED chip 10 and the lead pattern 23 are connected. Since the submount member 30 itself can be used as a part of the electric circuit, it is not necessary to form an electrode pattern on the surface of the submount member 30 and the cost can be reduced. Moreover, since the thickness of the submount member 30 is formed thicker than the insulating base material 22a, the LED chip 10 mounted on the submount member 30 is positioned above the surface of the insulating base material 22a. In other words, there is an advantage that light emitted from the LED chip 10 to the side can be prevented from being blocked by the insulating base material 22a and vignetting can be generated, and the light extraction efficiency can be improved.

  In each of the embodiments, only one LED chip 10 is mounted on the submount member 30, but each of the anode electrode or the cathode electrode on one surface of the mounting substrate 20 side (submount member 30 side). A plurality of LED chips, one of which is formed and the other of the anode electrode or the cathode electrode formed on the other surface, are mounted on the submount member 30, and the submount member 30 is lead via the bonding wire 14. By electrically connecting to the pattern 23, one electrode is electrically connected to the lead pattern 23 via the submount member 30 and the bonding wire 14, and the electrode formed on the other surface of each LED chip 10 is connected to the pattern 23. By electrically connecting directly to the lead pattern 23 via the bonding wire 14, one The sub-mount member 30 may be mounted a plurality of LED chips 10. Further, when mounting a plurality of LED chips 10 on the submount member 30, if a plurality of types of LED chips 10 that respectively irradiate light of different wavelengths are mounted, the irradiation light from the plurality of types of LED chips 10 can be mixed. Thus, a desired emission color can be obtained. In this case, the protective cover 70 does not need to have a color conversion function, and the protective cover 70 may be formed of only a translucent material, and the protective cover 70 may be used only for the purpose of protection.

(Embodiment 2)
Hereinafter, the light-emitting device 1 of this embodiment is demonstrated based on FIGS.

  The basic configuration of the light emitting device 1 of the present embodiment is substantially the same as that of the first embodiment, and as shown in FIGS. 4 and 5, the optical member 60 and the frame body 40 are the same translucent material (for example, silicone). Are different in that they are integrally molded. In addition, the same code | symbol is attached | subjected to the component which is common in Embodiment 1, and the description is abbreviate | omitted.

  The insulating base material 22a in the present embodiment is made of a white resin that covers the lead patterns 23 and 23 and the portions where the lead patterns 23 and 23 are not formed on the surface opposite to the metal plate 21 side. A resist layer 26 (see FIGS. 4 and 6) is laminated. Therefore, since the light emitted from the side surface of the LED chip 10 and incident on the surface of the resist layer 26 is reflected by the surface of the resist layer 26, the light emitted from the LED chip 10 is reflected on the metal plate 21 in the insulating substrate 22a. Can be prevented from being absorbed through the surface opposite to the upper surface (the upper surface in FIG. 4), and the light extraction efficiency to the outside can be improved to improve the light output.

  The resist layer 26 is formed with a circular opening 26a that exposes the inner lead portions 23a, 23a of the lead patterns 23, 23 in the vicinity of the window hole 24 of the insulating base material 22a, and has an insulating property. Circular openings 26b and 26b that expose the outer lead portions 23b and 23b of the lead patterns 23 and 23, respectively, are formed in the peripheral portion of the base material 22a.

  Further, the optical member 60 in the present embodiment has a light incident surface 60a on the sealing portion 50 side formed in a planar shape, and a light emitting surface 60b formed in a convex curved surface, and is formed in a plano-convex lens shape. Yes.

  Here, the optical member 60 and the frame body 40 are integrally formed of the same translucent material (for example, silicone) as described above (in other words, the optical member 60 and the frame body 40 are integrally formed integrally. The refractive index and the linear expansion coefficient are substantially the same as those of the sealing portion 50. In addition, it is preferable to use the material which has a linear expansion coefficient equivalent to the sealing material of the sealing part 50 as the translucent material of the optical member 60 and the frame 40. The optical member 60 and the frame body 40 may be integrally formed of a light-transmitting material that does not fall below the refractive index and elastic modulus of the sealing material of the sealing portion 50. For example, the sealing resin of the sealing portion 50 is acrylic. In the case of resin, the optical member 60 and the frame body 40 may be integrally formed of acrylic resin.

  Further, in the light emitting device 1 of the present embodiment, the LED chip 10 is disposed at a position separated from the plane including the outermost surface of the mounting substrate 20 (the surface of the resist layer 26) in the normal direction of the plane. In the lens block composed of the optical member 60 and the frame body 40, the space surrounded by the optical member 60 and the frame body 40 constitutes a housing recess for housing the LED chip 10 (see FIG. 4).

  By the way, as a manufacturing method of the light emitting device 1 of the present embodiment, as shown in FIG. 7, the LED chip 10 and the bonding wires 14 and 14 are electrically connected and then surrounded by the optical member 60 and the frame body 40. A transparent liquid sealing resin material (for example, silicone resin) 50c to be the sealing portion 50 is injected into the space (that is, the above-described storage recess), and the LED is placed in the storage recess with the frame body 40 side. A method of forming the sealing portion 50 by arranging the optical member 60 and the frame body 40 on the mounting substrate 20 so as to accommodate the chip 10 and curing the sealing resin material 50c is conceivable. However, in such a manufacturing method, voids may be generated in the sealing portion 50 during the manufacturing process. Therefore, it is preferable to manufacture by the following manufacturing method.

  That is, in manufacturing the light emitting device 1, after the LED chip 10 is mounted on the mounting substrate 20 and the LED chip 10 and the bonding wires 14 and 14 are electrically connected as shown in FIG. A space (housing recess) surrounded by the optical member 60 and the frame body 40 while covering the wires 14 and 14 with a transparent liquid first sealing resin material (for example, silicone resin) 50a which becomes a part of the sealing portion 50 ) Is injected with a second sealing resin material (for example, silicone resin) 50b, which is made of the same transparent liquid material as the first sealing resin material 50a, and is the other part of the sealing portion 50. The optical member 60 and the frame body 40 are arranged on the mounting substrate 20 so that the LED chip 10 is accommodated in the accommodating recess with the body 40 facing the mounting substrate 20, and the first and second sealings Fat material 50a, is brought into contact with 50b, it is to form the sealing portion 50 by curing Ryofutome resin material 50a, a 50b. According to such a manufacturing method, it is difficult to generate a void in the sealing portion 50 during the manufacturing process, and it is possible to provide the light emitting device 1 with high reliability and high light output.

  Here, if the first sealing resin material 50a is cured before the second sealing resin material 50b is injected into the housing recess, the viscosity of the first sealing resin material 50a is reduced and There is an advantage that voids (bubbles) confined in the storage recess are easily removed. In the present embodiment, the inner diameter of the circular opening 26 a formed in the resist layer 26 of the mounting substrate 20 is slightly larger than the outer diameter of the opening of the protective cover 70 (the edge contacting the mounting substrate 20). The protective cover 70 and the mounting substrate 20 are joined to the first sealing resin material 50a that has been set and flows into the vicinity of the inner peripheral surface of the opening 26a when the first sealing resin material 50a is potted. It is used as an adhesive.

  As described above, in the light emitting device 1 of the present embodiment, the optical member 60 and the frame body 40 are integrally formed of the same light-transmitting material, and thus the optical member 60 and the frame body 40 are configured as separate parts. The number of parts can be reduced as compared with the case where the optical member 60 is used, and the optical member 60 and the LED chip 10 can be easily aligned. Therefore, the light output caused by the deviation of the optical axis between the LED chip 10 and the optical member 60 can be reduced. The decrease can be suppressed.

(Embodiment 3)
Hereinafter, the light emitting device of this embodiment will be described with reference to FIGS. 9 and 10.

  The basic configuration of the light emitting device 1 of the present embodiment is substantially the same as that of the second embodiment. As shown in FIG. 9, the inner diameter of the opening 26a provided in the resist layer 26 is set to the opening of the protective cover 70 (the mounting substrate 20). The inner edge of the protective cover 70 and the peripheral edge of the opening 26a in the resist layer 26 over the entire circumference. The point which has joined by the junction part 75 which consists of differs. In addition, the same code | symbol is attached | subjected to the component which is common in Embodiment 2, and the description is abbreviate | omitted.

  In manufacturing the light emitting device 1, as in the second embodiment, after the LED chip 10 is mounted on the mounting substrate 20 and the LED chip 10 and the bonding wires 14 and 14 are electrically connected as shown in FIG. The LED chip 10 and the bonding wires 14, 14 are covered with a transparent liquid first sealing resin material (for example, silicone resin) 50 a that is a part of the sealing portion 50 and surrounded by the optical member 60 and the frame body 40. The second sealing resin material (for example, silicone resin) 50b made of the same transparent liquid material as that of the first sealing resin material 50a and the other part of the sealing portion 50 is placed in the space (housing recess). The optical member 60 and the frame body 40 are arranged on the mounting substrate 20 in such a manner that the LED chip 10 is stored in the storage recess with the frame body 40 facing the mounting substrate 20, 2 the sealing resin material 50a, is brought into contact with 50b, it is to form the sealing portion 50 by curing Ryofutome resin material 50a, a 50b. According to such a manufacturing method, as described in the second embodiment, a void is hardly generated in the sealing portion 50 during the manufacturing process, and the light emitting device 1 having high reliability and high light output is provided. be able to.

  Here, in manufacturing the light emitting device 1 of the present embodiment, the resist layer 26 prevents the first sealing resin material 50a from flowing into the joint portion of the protective cover 70. Since the edge on the 20 side and the mounting substrate 20 are bonded by an adhesive, the thickness of the bonding portion 75 interposed between the protective cover 70 and the mounting substrate 20 can be easily controlled, and the protective cover 70 The reliability of bonding with the mounting substrate 20 is improved. In addition, it is desirable to use the same material as that of the protective cover 70 as the adhesive constituting the joining portion 75.

(Embodiment 4)
Hereinafter, although the light-emitting device of this embodiment is demonstrated based on FIGS. 11-14, the same code | symbol is attached | subjected to the component similar to Embodiment 2, and the description is abbreviate | omitted.

  The light emitting device 1 of the present embodiment does not include the frame body 40 described in the second embodiment as shown in FIG. 11, and the optical member 60 that controls the light distribution of the light emitted from the LED chip 10 is a dome shape. It is formed in a hemispherical shape, and is disposed on one surface side of the mounting substrate 20 so as to house the LED chip 10 between the mounting substrate 20 and the mounting substrate 20. The sealing portion 50 that seals the LED chip 10 and the bonding wires 14 and 14 is made of a sealing resin material (for example, silicone resin) having translucency in a space surrounded by the optical member 60 and the mounting substrate 20. The protective cover 70 covers the optical member 60 on the one surface side of the mounting substrate 20 so that the air layer 80 is formed between the light emitting surface 60b of the optical member 60 and the protective cover 70. Arranged.

  In this embodiment, a flexible printed wiring board in which a pair of lead patterns 23 and 23 for feeding is formed on one surface side of an insulating base material 22a made of a polyimide film is used as the wiring board 22 in the mounting board 20. ing.

  Here, as shown in FIG. 12, each lead pattern 23, 23 is formed in an outer peripheral shape slightly smaller than half of the outer peripheral shape of the insulating base material 22a. Further, the resist layer 26 is exposed in a rectangular shape at each lead pattern 23, 23 in the vicinity of the window hole 24 of the wiring substrate 22, and at one location of each lead pattern 23, 23 at the periphery of the wiring substrate 22. The lead pattern 23 is patterned so as to be exposed, and in each lead pattern 23, a rectangular portion exposed in the vicinity of the window hole 24 (substantially central portions of two opposite sides of the window hole 24) is connected to the bonding wire 14. The inner lead portion 23 a is formed, and the circular portion exposed in the peripheral portion of the wiring board 22 is the outer lead portion 23 b.

  In this embodiment, as the LED chip 10, a cathode electrode (n electrode) which is a cathode side electrode (not shown) is formed on one surface of the mounting substrate 20 side (that is, the submount member 30 side), and an anode (not shown) is formed on the other surface. An anode electrode (p electrode) formed on the side electrode is used, and the cathode electrode is electrically connected to a submount member 30 made of a conductor or a semiconductor. Then, the anode electrode of the LED chip 10 and the inner lead portion 23a of one lead pattern 23 are electrically connected via the bonding wire 14, and the submount member 30 and the inner lead portion 23a of the other lead pattern 23 are bonded. It is electrically connected via a wire 14. Here, out of the two outer lead portions 23b and 23b, the outer lead portion 23b (the outer lead portion 23b on the right side in FIG. 13) that is electrically connected to the anode electrode of the LED chip 10 has a display of “+”. Since the outer lead 23b (the outer lead 23b on the left side in FIG. 13) that is formed and electrically connected to the cathode electrode is formed with a sign “−”, both outer leads 23b in the light emitting device 1 are formed. , 23b can be visually discriminated and erroneous connection can be prevented.

  By the way, in this embodiment, the window hole 24 provided in the wiring board 22 is rectangular, and as shown in FIG. 12, the inner lead part 23a is provided in the vicinity of the center part of two opposite sides of the rectangular window hole 24. However, the inner lead portion 23a may be provided in the vicinity of the ends of the two opposite sides of the window hole 24, and the length of the bonding wire 14 is increased, so that the bonding wire 14 is expanded and contracted due to the expansion and contraction of the sealing portion 50. The disconnection is less likely to occur and the reliability is improved.

  The LED chip 10 used in the present embodiment is a blue LED chip using a 6H—SiC substrate as a crystal growth substrate. As in the first embodiment, a semiconductor material such as Si is used as the material of the submount member 30. Although being used, the material of the submount member 30 may be a conductive material or a semiconductor material having a linear expansion coefficient relatively close to that of the LED chip 10 and a relatively high thermal conductivity.

  In the light emitting device 1 according to the present embodiment, the thickness of the submount member 30 is formed such that the surface of the submount member 30 is farther from the metal plate 21 than the surface of the resist layer 26 of the wiring board 22. In addition, light emitted from the LED chip 10 to the side can be prevented from being absorbed by the wiring board 22 through the inner peripheral surface of the window hole 24 of the wiring board 22. A reflective film that reflects light emitted from the LED chip 10 may be formed on the periphery of the bonding portion of the LED chip 10 on the surface of the submount member 30 on the side to which the LED chip 10 is bonded. The light emitted from the chip 10 to the side can be prevented from being absorbed by the submount member 30, and the light extraction efficiency to the outside can be further improved.

  On the other hand, the optical member 60 is formed of a translucent material (for example, silicone) as in the second embodiment, but in the second embodiment, the optical member 60 is formed in a plano-convex lens shape. In, it is formed in a dome shape (hemisphere). Here, in the optical member 60, the light emitting surface 60b is formed in a convex curved surface so that the light incident from the light incident surface 60a is not totally reflected at the interface between the light emitting surface 60b and the air layer 80, and the LED chip. 10 and the optical axis coincide with each other. Therefore, the light emitted from the LED chip 10 and incident on the light incident surface 60a of the optical member 60 can easily reach the protective cover 70 without being totally reflected at the interface between the light emitting surface 60b and the air layer 80, The total luminous flux can be increased. The light emitted from the side surface of the LED chip 10 propagates through the sealing portion 50, the optical member 60, and the air layer 80 to reach the protective cover 70 to excite the phosphor of the protective cover 70 or It passes through the protective cover 70 without colliding. The optical member 60 is formed to have a uniform thickness along the normal direction regardless of the position. In the present embodiment, a silicone resin is used as the material of the sealing portion 50, and the optical member 60 is formed of a silicone molded product. Therefore, the refractive index difference between the optical member 60 and the sealing portion 50 and Although the linear expansion coefficient difference can be reduced, when the material of the sealing portion 50 is an acrylic resin, the optical member 60 is also preferably formed of the acrylic resin.

  Further, the protective cover 70 has an inner surface 70 a formed along the light emitting surface 60 b of the optical member 60, and the light emitting surface 60 b and the protective cover 70 are in the normal direction regardless of the position of the light emitting surface 60 b. The distance from the inner surface 70a is a substantially constant value.

  In manufacturing such a light emitting device 1, for example, between the anode electrode of the LED chip 10 and one lead pattern 23 and between the submount member 30 and the other lead pattern 23 via bonding wires 14 and 14, respectively. After the electrical connection, the submount member 30 and the wiring are arranged so that the tip of the nozzle 401 of the dispenser 400 is aligned with the resin injection hole 28 continuously formed in the window hole 24 of the wiring board 22 as shown in FIG. A transparent liquid sealing resin (for example, silicone resin) that becomes a part of the sealing portion 50 is injected into the gap with the substrate 22 and then cured. Thereafter, a transparent liquid sealing resin (for example, silicone resin) that becomes the remaining portion of the sealing portion 50 is injected into the inside of the dome-shaped optical member 60, and then the optical member 60 is disposed at a predetermined position on the mounting substrate 20. Then, by hardening the sealing resin, the optical member 60 is fixed to the mounting substrate 20 at the same time as the sealing portion 50 is formed, and then the protective cover 70 is fixed to the mounting substrate 20. According to such a manufacturing method, air bubbles (voids) are less likely to be generated in the sealing portion 50 during the manufacturing process, and stress concentration on the bonding wire 14 due to the voids can be suppressed and reliability can be improved. .

  Even when the above manufacturing method is employed, bubbles may be generated in the sealing portion 50 during the manufacturing process, so that a large amount of liquid sealing resin is injected into the optical member 60. Is preferred.

  However, if a large amount of sealing resin is injected into the optical member 60, a part of the liquid sealing resin injected into the optical member 60 is part of the optical member 60 when the optical member 60 is disposed at a predetermined position on the mounting substrate 20. From the space surrounded by the mounting substrate 20 to the outside and spread to the surface of the resist layer 26, and light is absorbed by unnecessary portions formed by curing the overflowing sealing resin, There is a possibility that light is diffusely reflected by the unevenness and the light extraction efficiency of the light emitting device 1 as a whole is lowered.

  Therefore, in the light emitting device 1 of the present embodiment, as shown in FIGS. 11 and 13, a ring-shaped portion overlapping the edge of the opening of the optical member 60 on the one surface of the mounting substrate 20 and the opening of the protective cover 70. A plurality of resin reservoir holes 27 for storing sealing resin overflowing from the space surrounded by the optical member 60 and the mounting substrate 20 are provided between the ring-shaped portion overlapping the edge of the portion and the outer peripheral direction of the optical member 60. Are spaced apart from each other. Therefore, even if a part of the liquid sealing resin injected into the optical member 60 overflows outside from the space surrounded by the optical member 60 and the mounting substrate 20, the overflowing sealing resin is removed from the resin reservoir hole. 27, the sealing resin overflowing to a portion between the optical member 60 and the protective cover 70 on one surface of the mounting substrate 20 is not cured and an unnecessary portion is not formed. As a result, it is possible to suppress the light extraction efficiency from being reduced due to the absorption of light and the irregular reflection of light due to the unevenness of the unnecessary portion, and the light output can be increased.

  Here, each resin reservoir hole 27 includes a through hole 27a formed in the wiring board 22 and a recess 27b formed in a portion corresponding to the through hole 27a in the metal plate 21 (see FIG. 11). Even if the thickness of the wiring board 22 (that is, the insulating base material 22a) is reduced, the depth dimension of the resin reservoir hole 27 can be increased by sufficiently increasing the thickness of the metal plate 21, and as a result, the resin reservoir hole. 27 can increase the amount of the sealing resin that can be stored in 27. In addition, the sealing resin cured in the resin reservoir hole 27 functions as a heat insulating portion that prevents heat transfer from the LED chip 10 to the protective cover 70, and the temperature of the protective cover 70 accompanying the heat generation of the LED chip 10. The rise can be suppressed, and a decrease in the luminous efficiency of the phosphor due to the heat generation of the LED chip 10 can be suppressed.

  Furthermore, in the present embodiment, between the ring-shaped portion that overlaps the edge of the opening of the optical member 60 and the ring-shaped portion that overlaps the edge of the opening of the protective cover 70 on the one surface of the mounting substrate 20. And a ring-shaped light absorption preventing substrate 140 covering each resin reservoir hole 27 (see FIGS. 11 and 14). The light absorption preventing substrate 140 has a white resist layer that reflects light from the LED chip 10 and the protective cover 70 on the surface opposite to the mounting substrate 20 side. It is possible to prevent the light from being absorbed by the resin portion made of the sealing resin that has accumulated in the hole 27 and is cured. The light absorption preventing substrate 140 is filled with the sealing resin overflowing when the optical member 60 is arranged at a predetermined position of the mounting substrate 20 in each resin reservoir hole 27, and then the above-mentioned of the mounting substrate 20. What is necessary is just to mount on one surface side, and when hardening sealing resin after that, it will adhere to the mounting board | substrate 20 with sealing resin. Here, as shown in FIGS. 12 and 14, the ring-shaped light absorption preventing substrate 140 is formed with a plurality of notches 142 for exposing minute regions of the resin reservoir holes 27. When the sealing resin in the service hole 27 is cured, air can easily escape and generation of voids can be suppressed.

  Here, in the light emitting device 1 according to the present embodiment, since the plurality of resin reservoir holes 27 are provided apart from each other in the outer peripheral direction of the optical member 60, the end of the optical member 60 is formed on the one surface of the mounting substrate 20. While the distance between the portion overlapping the edge and the portion overlapping the edge of the protective cover 70 is shortened, the formation of an unnecessary portion made of the sealing resin on the one surface of the mounting substrate 20 is suppressed. In addition, since the lead patterns 23 and 23 can be prevented from being separated by the resin reservoir hole 27, the resistance of the power supply path to the LED chip 10 can be reduced.

  In each of the above-described embodiments, a blue LED chip whose emission color is blue is adopted as the LED chip 10 and a SiC substrate is adopted as the conductive substrate 11 which is a substrate for crystal growth, but instead of the SiC substrate. A GaN substrate may be used, and when a SiC substrate or a GaN substrate is used, the thermal conductivity of the crystal growth substrate is higher than when a sapphire substrate as an insulator is used as the crystal growth substrate. The thermal resistance of the crystal growth substrate can be reduced. The light emission color of the LED chip 10 is not limited to blue, and may be red or green, for example. That is, the material of the light emitting portion 12 of the LED chip 10 is not limited to the GaN-based compound semiconductor material, and a GaAs-based compound semiconductor material, a GaP-based compound semiconductor material, or the like may be employed according to the emission color of the LED chip 10. The material for the crystal growth substrate may be appropriately selected according to the material of the portion 12.

  In each embodiment described above, only one LED chip 10 is mounted on the submount member 30, but a plurality of LED chips 10 may be mounted on the submount member 30. When a plurality of LED chips 10 are mounted on the submount member 30, if a plurality of types of LED chips 10 that irradiate light of different wavelengths are mounted, the light emitted from the plurality of types of LED chips 10 is mixed. A desired luminescent color can be obtained. In this case, the protective cover 70 does not need to have a color conversion function, and the protective cover 70 may be formed of only a translucent material, and the protective cover 70 may be used only for the purpose of protection.

  It should be noted that a wide variety of different embodiments can be configured without departing from the spirit and scope of the present invention, and the present invention is not limited to a specific embodiment.

It is a schematic sectional drawing which shows embodiment. It is a general | schematic disassembled perspective view which showed the same and partially fractured | ruptured. It is a principal part schematic plan view which shows the same as the above. FIG. 6 is a schematic cross-sectional view showing a second embodiment. It is a general | schematic disassembled perspective view which showed the same and partially fractured | ruptured. It is a schematic plan view of the wiring board in the same as the above. It is a schematic sectional drawing explaining the manufacturing method same as the above. It is a schematic sectional drawing explaining the other manufacturing method same as the above. FIG. 6 is a schematic cross-sectional view showing a third embodiment. It is a schematic sectional drawing explaining the manufacturing method same as the above. FIG. 6 is a schematic cross-sectional view showing a fourth embodiment. It is a general | schematic disassembled perspective view fractured | ruptured partially same as the above. It is explanatory drawing of a manufacturing method same as the above. It is a schematic exploded perspective view same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting device 10 LED chip 14 Bonding wire 20 Mounting board 21 Metal plate (heat-transfer plate)
22 Wiring Board 22a Insulating Base Material 23 Lead Pattern 30 Submount Member 50 Sealing Portion 60 Optical Member 70 Protective Cover

Claims (1)

  An LED chip, a mounting substrate on which the LED chip is mounted, a sealing portion that seals the LED chip and a bonding wire that is electrically connected to the electrode of the LED chip formed of a translucent material, and sealing An optical member that controls the light distribution of the emitted light from the LED chip that has passed through the portion, and a protective cover that is formed of a material containing at least a light-transmitting material and is disposed on the mounting substrate so as to cover the optical member In the LED chip, one of the anode electrode and the cathode electrode is formed on one surface of the mounting substrate side, and the other of the anode electrode and the cathode electrode is formed on the other surface. A heat transfer plate made of a thermally conductive material on which the LED chip is mounted, and laminated on the LED chip non-mounting portion of the heat transfer plate and bonded to the LED chip electrode The lead pattern that is electrically connected through the ear is made of an insulating base formed on the surface opposite to the heat transfer plate, and a submount member is arranged on the mounting portion of the LED chip on the heat transfer plate, The LED chip is mounted on the heat transfer plate via the submount member, and the material of the submount member is either a conductor or a semiconductor and has a linear expansion coefficient substantially the same as the material of the LED chip. A light-emitting device, wherein one electrode of an LED chip is electrically connected to a mount member, and the sub-mount member and the lead pattern are electrically connected via the bonding wire.

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