JP2010087005A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device reducing an effective size of a light source determined by an LED chip and a reflecting section. <P>SOLUTION: The light emitting device A includes: a rectangular plate-shaped LED chip 1; a rectangular plate-shaped mounting board 2 with the LED chip 1 mounted on one surface; and a reflecting section 3 arranged on the one surface of the mounting board 2 and having reflecting surfaces 31 that reflect light emitted sideward from the LED chip 1 to the side opposite to the mounting board 2 in the LED chip 1. The reflecting section 3 is formed such that the reflection surfaces 31 rise from respective four sides of an outer periphery of a projection region M of the LED chip 1 on the one surface of the mounting board 2. Here, the reflecting section 3 includes a plurality (four in this embodiment) of reflecting elements 30 separated in the circumferential direction of the outer periphery of the projection region M. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  Conventionally, as shown in FIGS. 10 and 11, a rectangular plate-shaped LED chip 1 ′, a rectangular plate-shaped mounting substrate 2 ′ on which the LED chip 1 ′ is mounted on one surface side, and a mounting substrate 2 ′ On the one surface side, a reflecting surface 31 ′ is disposed so as to surround the LED chip 1 ′ and reflects light emitted from the LED chip 1 ′ to the side opposite to the mounting substrate 2 ′ side of the LED chip 1 ′. There has been proposed a light emitting device A ′ including a reflective portion 3 ′ having the same (for example, see Patent Document 1).

  Here, the mounting substrate 2 ′ is provided with conductor patterns 22 ′ and 22 ′ for supplying power to the LED chip 1 ′ on one surface side of the insulating substrate 21 ′, and the LED on the center portion on the one surface side. An anode electrode (not shown) and a cathode electrode (not shown) of the chip 1 ′ are joined and electrically connected to the conductor patterns 22 ′ and 22 ′ via bumps (not shown), respectively. In short, the LED chip 1 'is flip-chip mounted on the mounting substrate 2'. In Patent Document 1, a mounting structure in which the anode electrode and the cathode electrode of the LED chip 1 ′ are electrically connected to the conductor patterns 22 ′ and 22 ′ via bonding wires may be employed. Are listed.

  Further, the reflecting portion 3 ′ has a circular frame-like shape, and the opening area gradually increases as the distance from the one surface of the mounting substrate 2 ′ increases. The reflecting portion 3 ′ is formed of resin, metal, or the like, and a metal film having a high reflectance with respect to light emitted from the LED chip 1 ′ is deposited on the inner side surface, and the surface of the metal film is the reflecting surface 31 ′. Is configured. Note that the outer peripheral shape of the reflecting portion 3 ′ is formed in a rectangular shape.

  Patent Document 1 also describes that a sealing portion made of a transparent resin that covers the LED chip 1 ′ is provided in a space surrounded by the mounting substrate 2 ′ and the reflection portion 3 ′. For example, the LED chip If a blue LED chip that emits blue light is adopted as 1 ′ and a phosphor that emits yellow light by being excited by the blue light emitted from the LED chip 1 ′ is dispersed in the sealing portion, White light can be obtained as mixed light with yellow light.

Even if the light distribution characteristic of the LED chip 1 ′ is, for example, diffusive light distribution, the light emitting device A ′ described above has the LED chip mounted on the one surface side of the mounting substrate 2 ′ by the reflection portion 3 ′. Since the light emitted from 1 ′ to the side is reflected by the reflecting surface 31 ′ of the reflecting portion 3 ′, the light distribution of the light emitted from the light emitting device A ′ is controlled and emitted from the light emitting device A ′. The directivity of light can be strengthened.
JP 2005-294292 A

  By the way, when the above-described light emitting device A ′ is used by being incorporated in, for example, a lighting fixture having a light distribution control member (for example, a lens, a reflector, etc.), the light use efficiency and the light distribution controllability by the light distribution control member In order to improve the above, it is required to reduce the effective light source size of the light emitting device A ′.

  However, in the above-described light emitting device A ′, since the outer peripheral shape of the LED chip 1 ′ is rectangular, the opening shape of the reflecting portion 3 ′ is circular, so that the effective is determined by the LED chip 1 ′ and the reflecting portion 3 ′. The light source size (here, the opening size of the reflecting portion 3 ′ becomes an effective light source size) becomes too large than the chip size of the LED chip.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a light-emitting device capable of reducing the effective light source size determined by the LED chip and the reflection portion.

  The invention of claim 1 includes a rectangular plate-shaped LED chip, a mounting substrate on which the LED chip is mounted on one surface side, and light emitted from the LED chip to the side opposite to the mounting substrate side in the LED chip. And a reflecting portion having a reflecting surface that reflects toward the surface, the reflecting surface of the reflecting portion being formed so as to rise from each of the four sides of the outer peripheral line of the projection area of the LED chip on the one surface of the mounting substrate. And

  According to the present invention, the reflecting surface of the reflecting portion is formed so as to rise from each of the four sides of the outer peripheral line of the projection area of the LED chip on one surface of the mounting substrate, so that the effective that is determined by the LED chip and the reflecting portion. The light source size can be reduced.

  According to a second aspect of the present invention, in the first aspect of the invention, the reflective portion is configured by a plurality of reflective elements spaced apart in the circumferential direction of the outer peripheral line, and the mounting substrate is formed on the LED chip on the one surface side. An electrically connected conductor pattern is provided between the reflective elements adjacent in the circumferential direction.

  According to the present invention, it is possible to reduce the effective light source size while providing a conductor pattern electrically connected to the LED chip on the one surface side of the mounting substrate.

  A third aspect of the invention is characterized in that, in the first aspect of the invention, the mounting substrate is formed with a feed through-hole wiring electrically connected to the LED chip.

  According to the present invention, for example, there is an advantage that a wire bonding step is not required when mounted on a circuit board housed in a fixture body such as a lighting fixture. Further, if through-hole wiring is formed outside the projection area of the LED chip in the mounting board, the entire projection area of the LED chip on the other surface side of the mounting board is bonded to a circuit board or the like by soldering or the like. It is possible to improve heat dissipation.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the reflection portion is formed integrally with the mounting substrate.

  According to the present invention, the cost can be reduced by simplifying the manufacturing process as compared with the case where the reflecting portion and the mounting substrate are separate members and both need to be fixed.

  According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the reflecting portion and the mounting substrate are formed using a silicon substrate.

  According to the present invention, the reflective portion can be formed by crystal anisotropic etching of the silicon substrate, and the reproducibility of the rising angle of the reflective surface can be improved.

  According to the first aspect of the present invention, there is an effect that an effective light source size determined by the LED chip and the reflection portion can be reduced.

(Embodiment 1)
As shown in FIG. 1, the light emitting device A of the present embodiment includes a rectangular plate-shaped LED chip 1, a rectangular plate-shaped mounting substrate 2 on which the LED chip 1 is mounted on one surface side, and the above-described mounting substrate 2. Light that is arranged on one surface side and emitted sideways from the LED chip 1 (light emitted from the side surface of the LED chip 1 or the surface opposite to the mounting substrate 2 side of the LED chip 1 is low relative to the surface. And a reflecting portion 3 having a reflecting surface 31 that reflects light emitted in an oblique direction of the angle to the side opposite to the mounting substrate 2 side in the LED chip 1.

  The LED chip 1 is a GaN-based blue LED chip that emits blue light, and an anode electrode (not shown) and a cathode electrode (not shown) are formed on one surface side in the thickness direction. 2 is flip-chip mounted. The LED chip 1 is not limited to the blue LED chip, and may be, for example, an ultraviolet LED chip, a red LED chip, a green LED chip, or the like.

  Further, the mounting substrate 2 is formed using a silicon substrate 20, and a pair of conductor patterns 22 and 22 for supplying power to the LED chip 1 are formed on the one surface side, and in the central portion on the one surface side. The anode electrode and the cathode electrode of the LED chip 1 are joined and electrically connected to the conductor patterns 22 and 22 via the bumps 4 and 4, respectively. Here, an insulating film 23 made of a silicon oxide film that electrically insulates both the conductor patterns 22 and 22 and the silicon substrate 20 is formed on the one surface side of the mounting substrate 2. In short, the two conductor patterns 22 and 22 are formed on the insulating film 23. The conductor patterns 22 and 22 are composed of a laminated film of an adhesion improving film made of a Ti film and an Au film. The bumps 4 are composed of Au bumps.

  Here, the conductor patterns 22 and 22 are formed with connection portions 22a and 22a to which the LED chip 1 is joined and electrically connected in the projection region M of the LED chip 1 on the one surface of the mounting substrate 2, respectively. Since the planar size of the anode electrode of the LED chip 1 is larger than the planar size of the cathode electrode, the connection portion corresponding to the anode electrode (hereinafter referred to as the first connection) of the pair of connection portions 22a and 22a. The planar size of a connecting portion 22a corresponding to the cathode electrode (hereinafter referred to as a second connecting portion) 22a is larger, and the first connecting portion 22 is the first connecting portion 22a. Compared to the two connection portions 22, the bumps 4 are joined to each other. In the present embodiment, the LED chip 1 having a chip size of 1 mm □ is used, and the first connection portion 22 is joined to the anode electrode via the 25 bumps 4 to form the second connection portion. Although 22 is joined to the cathode electrode through one bump 23, the chip size of the LED chip and the number of bumps 4 are not particularly limited.

  In the light emitting device A of the present embodiment, the LED chip 1 is flip-chip mounted on the mounting substrate 2, and the anode electrode and the cathode electrode of the LED chip 1 are electrically connected to the conductor patterns 22 and 22 via bonding wires. A mounting structure that connects to may be adopted. The LED chip 1 has the anode electrode and the cathode electrode formed on the one surface side in the thickness direction. The anode electrode is formed on the one surface side in the thickness direction, and the cathode electrode is formed on the other surface side. An electrode in which an electrode is formed may be used. In this case, one of the two electrodes of the anode electrode and the cathode electrode is connected to one conductor pattern 22 by, for example, conductive bonding made of an AuSn layer. What is necessary is just to electrically connect through a layer and to electrically connect the other electrode to the other conductor pattern 22 through a bonding wire.

  In addition, the reflecting portion 3 is formed such that the reflecting surface 31 rises from each of the four sides of the outer peripheral line of the projection area M of the LED chip 1 on the one surface of the mounting substrate 2. In addition, the projection area | region M of LED chip 1 is square shape.

  Here, the reflecting portion 3 is configured by a plurality of (four in the present embodiment) reflecting elements 30 that are spaced apart in the circumferential direction of the outer peripheral line of the projection region M, and the mounting substrate 2 includes the conductor patterns 22 and 22. Parts other than the connecting portions 22a and 22a are disposed between the reflecting elements 30 adjacent in the circumferential direction, and the end portions of the conductor patterns 22 and 22 opposite to the connecting portions 22a and 22a are for external connection. The electrodes 22b and 22b are configured. In the reflection part 3 described above, the four reflection elements 30 are formed independently for each of the four sides of the outer peripheral line of the projection area M of the LED chip 1 on the one surface of the mounting substrate 2, and in the circumferential direction. The lengths of the reflective elements 30 are all set to the same value. In the light emitting device A of the present embodiment, the reflection surface 31 of the reflection unit 3 is parallel to the side of the LED chip 1 in plan view.

  By the way, the reflection part 3 is formed using the above-mentioned silicon substrate 20. In short, a structure composed of the reflective portion 3 and the mounting substrate 2 is formed using one silicon substrate 20, and the reflective portion 3 is formed integrally with the mounting substrate 2. Thus, the cost can be reduced by simplifying the manufacturing process as compared with the case where the reflecting portion 3 and the mounting substrate 2 are separate members and both need to be fixed. Here, as the silicon substrate 20, a single crystal silicon substrate having a main surface of (100) plane is used.

  Here, the reflecting portion 3 is formed by crystal anisotropic etching of the silicon substrate 20, and the reproducibility of the rising angle of the reflecting surface 31 can be improved. In the present embodiment, the mask for the crystal anisotropic etching is designed so that the rising angle of the reflecting surface 31 is 54.7 °.

  In the present embodiment, the reflecting portion 3 is constituted by four reflecting elements 30. However, as shown in FIG. 2, the reflecting portion 3 is formed in a rectangular frame shape along the outer peripheral line of the projection region M. Alternatively, as shown in FIG. 3, it may be constituted by two reflecting elements 30 having an L shape in plan view along two adjacent sides of the outer peripheral line of the projection region M. In addition, as shown in FIG. 4, the reflection portion 3 may be formed separately from the mounting substrate 2 using a silicon substrate 30 a different from the silicon substrate 20 and fixed to the mounting substrate 20. Further, the rising angle of the reflecting surface 31 of the reflecting portion 3 is not limited to 54.7 °, and may be approximately 45 ° as shown in FIG. 5, for example. Further, the material of the mounting substrate 2 and the reflective portion 3 is not limited to Si, and for example, ceramics or the like may be used. For the reflective portion 3, a metal material (for example, Al) or a high heat resistant resin (for example, PBT) Etc.) may be adopted.

  In the light emitting device A of the present embodiment described above, the reflecting surface 31 of the reflecting portion 3 is formed so as to rise from each of the four sides of the outer peripheral line of the projection region M of the LED chip 1 on the one surface of the mounting substrate 2. Therefore, the effective light source size determined by the LED chip 1 and the reflecting portion 3 can be reduced. Therefore, when the light-emitting device A of the present embodiment is used by being incorporated in a lighting fixture having a light distribution control member (for example, a lens, a reflector, etc.), for example, the light use efficiency and the light distribution by the light distribution control member Controllability can be improved.

  Here, as shown in FIG. 6, as the structural parameters of the light emitting device A, the distance W from the outer peripheral line of the projection area M of the LED chip 1 on the mounting substrate 2 to the reflecting portion 3, the height H of the reflecting portion 3, and the reflecting portion 3. Comparison of Example 1 in which the rising angle φ of the reflective surface 31 is set to W = 0 μm, H = 250 μm, φ = 54.7 °, and W = 150 μm, H = 250 μm, φ = 54.7 ° On Example 1, Example 2 in which W = 0 μm, H = 250 μm, φ = 45 °, and Comparative Example 2 in which W = 150 μm, H = 250 μm, φ = 45 °, A light receiver (not shown) is arranged so that the center of the light receiving surface is positioned, the light receiving angle 2θ of the light receiver is set to 128 °, and the reflecting surface 31 rising from each of the four sides of the outer peripheral line of the projection region M is arranged. When the circumferential length is changed variously, The light flux ratio detected by the light receiving device relative to the total flux from A (light flux ratio of the chip directly upward) shown in FIG. Here, in FIG. 7, “A” represents the luminous flux ratio in the direction directly above the chip of Example 1, “B” represents the luminous flux ratio in the direction immediately above the chip of Comparative Example 1, and “C” represents the direction directly above the chip of Example 2. “D” indicates the light flux ratio in the direction directly above the chip of Comparative Example 1. From the comparison between Example 1 and Comparative Example 1 in FIG. 7 and the comparison between Example 2 and Comparative Example 2, the reflective surface 31 of the reflective portion 3 stands from the outer peripheral line of the projection region M of the LED chip 1 on the mounting substrate 2. It can be seen that the directivity can be strengthened by raising it (that is, by setting W = 0). In addition, the length of each of the four sides of the LED chip 1 in plan view is 1 mm (1000 μm). From FIG. 7, the length of the reflecting surface 31 is about 80% of each side of the LED chip 1 (that is, about 800 μm). It can be seen that a great effect can be obtained.

  Further, in the light emitting device A of the present embodiment, the reflecting portion 3 is configured by a plurality of reflecting elements 30 that are separated in the circumferential direction of the outer peripheral line of the projection region M, and the mounting substrate 2 is an LED chip on the one surface side. Since the conductive patterns 22 and 22 electrically connected to 1 are disposed between the reflective elements 30 adjacent in the circumferential direction, the conductive patterns 22 and 22 are electrically connected to the LED chip 1 on the one surface side of the mounting substrate 2. The effective light source size can be reduced while the conductor patterns 22 and 22 are provided.

  By the way, if the power supply through-hole wiring electrically connected to the LED chip 1 is formed in the projection area of the LED chip 1 in the mounting substrate 2, the LED chip 1 as in the configuration shown in FIG. Therefore, it is not necessary to provide the conductive patterns 22 and 22 for supplying power to the side of the LED chip 1, and the light emitted from the LED chip 1 can be efficiently extracted to the outside. Further, if the through-hole wiring is formed in the mounter plate 2, there is an advantage that a wire bonding step is not required when mounted on a circuit board housed in a fixture body such as a lighting fixture. Further, if the through-hole wiring is formed outside the projection area M of the LED chip 1 in the mounting substrate 2, the entire projection area of the LED chip 1 on the other surface side of the mounting substrate 2 is used as a fixture such as a lighting fixture. It becomes possible to bond to a conductive pattern for heat dissipation of a circuit board housed in the main body or the like by solder or the like, and heat dissipation can be improved.

(Embodiment 2)
The basic configuration of the light emitting device A of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 8, the mounting substrate 2 is emitted from the LED chip 1 and the unit substrate 5 mounted on one surface side. LED chip formed of a translucent material containing a phosphor that emits light having a wavelength longer than that of LED chip 1 (ie, light having a color different from that emitted from LED chip 1) when excited by the reflected light. The difference is that a dome-shaped color conversion member (wavelength conversion member) 6 disposed on the one surface side of the unit substrate 5 is provided so as to surround 1 with the unit substrate 5. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  In the light emitting device A of the present embodiment, a GaN-based blue LED chip that emits blue light is used as the LED chip 1, and the phosphor of the color conversion member 6 is excited and broadened by the blue light emitted from the LED chip 1. The yellow light emitted from the LED chip 1 and transmitted through the color conversion member 6 and the yellow light emitted from the yellow phosphor of the color conversion member 6 are used. Is emitted from the light exit surface of the color conversion member 6 and white light can be obtained (note that the arrow in FIG. 8 schematically shows the traveling path of the light emitted from the LED chip 1). ing).

  The unit substrate 5 includes a heat transfer plate 51 made of a heat conductive material (for example, Cu) and the conductor patterns 22 and 22 described in the first embodiment on one surface side of the insulating base (see FIG. 1). A wiring pattern that is electrically connected via a bonding wire is formed, and a window hole 53 in which the mounting substrate 2 is spaced apart from the inside is formed in the thickness direction so as to be fixed to the heat transfer plate 51. The heat generated in the LED chip 1 can be dissipated through the mounting substrate 2 and the heat transfer plate 51.

  Moreover, the color conversion member 6 uses the mixed material which disperse | distributed the particulate yellow fluorescent substance which is excited by the blue light radiated | emitted from LED chip 1 in the translucent material which consists of silicone resin, and radiates | emits yellow light. It is formed in a dome shape. The translucent material used as the material of the color conversion member 6 is not limited to a silicone resin. For example, an organic / inorganic hybrid in which an acrylic resin, glass, an organic component and an inorganic component are mixed and combined at the nm level or the molecular level. Materials etc. may be adopted. Further, the phosphor contained in the translucent material used as the material of the color conversion member 6 is not limited to the yellow phosphor, and a plurality of types of phosphors may be used for the purpose of improving color adjustment and color rendering. White light with high color rendering properties can be obtained by using a red phosphor and a green phosphor. Here, when a plurality of types of phosphors are used, the phosphor is not necessarily a combination of phosphors having different emission colors, and for example, a plurality of types of phosphors having an emission color of yellow and different emission spectra may be combined.

  Also in the light emitting device A of the present embodiment described above, as in the first embodiment, each of the four sides of the outer peripheral line of the projection region M of the LED chip 1 on the one surface of the mounting substrate 2 is the reflecting surface 31 of the reflecting portion 3. Therefore, the effective light source size determined by the LED chip 1 and the reflecting portion 3 can be reduced.

(Embodiment 3)
The basic configuration of the light emitting device A of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 9, each of the conductor patterns 22 and 22 (see FIG. 1) described in the first embodiment is mounted on the mounting substrate 2. Through-hole wirings 22c and 22c that are electrically connected and penetrated in the thickness direction of the silicon substrate 20 are formed, and a metal material that is electrically connected to each of the through-hole wirings 22c and 22c on the other surface side of the mounting substrate 2 ( The difference is that lead terminals 7 and 8 made of, for example, Cu are fixed. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  Here, each through-hole wiring 22c, 22c is electrically insulated from the silicon substrate 20 by an insulating film (not shown). The lead terminals 7 and 8 are formed by using a lead frame, and are electrically insulated from the silicon substrate 20 by an insulating layer (not shown).

  Also in the light emitting device A of the present embodiment described above, as in the first embodiment, each of the four sides of the outer peripheral line of the projection region M of the LED chip 1 on the one surface of the mounting substrate 2 is the reflecting surface 31 of the reflecting portion 3. Therefore, the effective light source size determined by the LED chip 1 and the reflecting portion 3 can be reduced. In the light emitting device A of the present embodiment, the through-hole wirings 22c and 22c are formed outside the projection area M of the LED chip 1 in the mounting substrate 2, so that the LED chip 1 on the other surface side of the mounting substrate 2 A part of one of the lead terminals 7 can be disposed on the entire surface of the projection region, and the lead terminal 7 can be joined to a circuit board or the like housed in a fixture body such as a lighting fixture by soldering or the like. Can be improved.

  In the first to third embodiments, the reflecting surface 31 of the reflecting portion 3 is formed so as to rise from each of the four sides of the outer peripheral line of the projection region M of the LED chip 1 on the one surface of the mounting substrate 2. However, in consideration of the installation tolerance of the LED chip 1 and the like, the reflecting surface 31 may rise from a slightly outside of the outer peripheral line.

The light-emitting device of Embodiment 1 is shown, (a) is a schematic perspective view, (b) is a schematic sectional drawing, (c) is a principal part schematic plan view. It is a principal part schematic perspective view which shows the other structural example same as the above. It is a principal part schematic perspective view which shows the other structural example same as the above. It is a principal part disassembled perspective view of the other structural example same as the above. It is a principal part schematic perspective view which shows the other structural example same as the above. It is explanatory drawing of the structural parameter of a light-emitting device same as the above. It is characteristic explanatory drawing of a light-emitting device same as the above. 6 is a schematic cross-sectional view showing a light emitting device of Embodiment 2. FIG. 6 is a schematic cross-sectional view showing a light emitting device according to Embodiment 3. FIG. It is a general | schematic disassembled perspective view of the light-emitting device of a prior art example. The same as the above, (a) is a schematic plan view, and (b) is a schematic cross-sectional view along B-B 'of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LED chip 2 Mounting board 3 Reflection part 20 Silicon substrate 30 Reflective element 31 Reflective surface A Light-emitting device M Projection area

Claims (5)

  A rectangular plate-shaped LED chip, a mounting substrate on which the LED chip is mounted on one surface side, and a reflection surface that reflects light emitted from the LED chip to the side toward the side opposite to the mounting substrate side of the LED chip A light emitting device comprising: a reflection portion, wherein the reflection surface of the reflection portion is formed so as to rise from each of the four sides of the outer peripheral line of the projection area of the LED chip on the one surface of the mounting substrate.   The reflective portion is configured by a plurality of reflective elements spaced apart in the circumferential direction of the outer circumferential line, and the mounting substrate has a conductor pattern electrically connected to the LED chip on the one surface side in the circumferential direction. The light emitting device according to claim 1, wherein the light emitting device is disposed between adjacent reflecting elements.   The light-emitting device according to claim 1, wherein the mounting substrate is formed with a power supply through-hole wiring electrically connected to the LED chip.   4. The light emitting device according to claim 1, wherein the reflecting portion is formed integrally with the mounting substrate.   5. The light emitting device according to claim 1, wherein the reflection portion and the mounting substrate are formed using a silicon substrate.

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