JP2006173392A - Light emitting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting apparatus various characteristics such as the reliability and the color mixing property of which are improved wherein a plurality of light emitting elements can be arranged at a narrow pitch, even when a plurality of the light emitting elements are employed for the apparatus so as to be capable of realizing downsizing. <P>SOLUTION: A composite LED chip 2 is formed by mounting a plurality of LED elements 12A to 12C of a flip-chip type on one intermediate board 11 at the narrow pitch in the arrangement of them. The composite LED chip 2 is mounted onto a conductor pattern on a reflect case 10 through metallic bonding. Since the LED elements 12A to 12C are mounted on the intermediate board 11 resulting in that the LED elements 12A to 12C can mutually be arranged at the narrow pitch, the downsizing and the enhancement of the color mixing property or the like can be attained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light-emitting device having a plurality of light-emitting elements such as LEDs and LDs, and in particular, even when a plurality of light-emitting elements are used, a narrow pitch can be achieved, miniaturization can be realized, and various characteristics such as reliability and color mixing properties The present invention relates to a light-emitting device with improved brightness.

  LEDs (Light Emitting Diodes) have features such as power saving, long life, and maintenance-free, so they can be used for lamps of electronic devices and other equipment, signal transmission, traffic lights, advertising towers, etc. It is also used in outdoor equipment, automotive lamps, backlights for liquid crystal display devices, and the like.

  Conventionally, the emission color of the LED has been a single color, but with the practical use of blue light emitting diodes, LEDs of a plurality of emission colors, for example, three colors of red (R), green (G), and blue (B) Light emitting devices that obtain white light by combining the above are put into practical use.

  FIG. 8 shows a configuration of a conventional light emitting device. The light emitting device 100 includes a reflective case 101 having a rectangular outer shape and a circular recess 101a at the center of the upper surface thereof, and a plurality of LED elements 102A, 102B, and 102C mounted on the bottom 101b of the recess 101a. Prepare.

  The reflective case 101 is made, for example, by molding a resin material or the like. A reflective layer 101c is formed on the inner wall surface of the recess 101a by aluminum vapor deposition, silver paint, or the like, and the LED elements 102A to 102C are further provided inside. A conductive pattern (not shown) for connecting the electrode portion to an external power supply device or the like is formed.

  The LED element 102A has a blue emission color, and the LED element 102C has a green emission color. Each LED element 102C has a pair of electrodes (not shown) on the upper surface thereof, and a conductive pattern (not shown) on the bottom 101b and a plurality of bonding wires 103. Each is connected. The LED element 102B has a red light emission color, has a vertical structure, connects an electrode (not shown) on the bottom surface and a conductive pattern on the bottom portion 101b, and connects to a conductive pattern on the bottom portion 101b by a bonding wire 103 from an electrode (not shown) on the top surface. Has been.

  In the light emitting device 100, when power is supplied to the LED elements 102 </ b> A to 102 </ b> C from an external power supply device, the LED elements 102 </ b> A to 102 </ b> C are simultaneously turned on and emitted light is emitted from the upper surface provided with the plurality of bonding wires 103. The light emission colors of the LED elements 102A to 102C are mixed and become, for example, white light, which is emitted above the recess 101a. Further, part of the emitted light is reflected by the reflective layer 101c and emitted to the outside.

  However, in the light emitting device having the configuration of FIG. 8, it is necessary to connect the electrodes of the LED elements 102 </ b> A to 102 </ b> C and the conductive patterns on the bottom 101 b with bonding wires 103 after mounting the LED elements 102 </ b> A to 102 </ b> C on the bottom 101 b of the reflect case 101. And it is difficult to narrow the interval between the LED elements 102A to 102C.

  As an LED that does not require a bonding wire to be connected to the LED element, for example, there is one disclosed in Patent Document 1.

  FIG. 9 shows a conventional light-emitting device configured using the LED elements disclosed in Patent Document 1. The light emitting device 100 has a rectangular outer shape, and is mounted on a reflective case 101 having a circular concave portion 101a at the center of the upper surface thereof, and submounts 104A to 104C as intermediate substrates on a bottom portion 101b of the concave portion 101a. And a plurality of LED elements 102A, 102B, 102C.

  The LED elements 102A to 102C are overlapped so that the central axis thereof coincides with the central axis of the submounts 104A to 104C, and the LED elements 102A to 102C are arranged on the submounts 104A to 104C around the central axis. On the other hand, it is installed by rotating approximately 45 degrees. A pair of extraction electrodes for the LED elements 102A to 102C is formed at the corners of the submounts 104A to 104C. Then, the LED elements 102A to 102C are mounted on the submounts 104A to 104C with gold bumps or the like to form an LED portion, which is mounted on the bottom 101b of the reflective case 101, and further the conductive on the submounts 104A to 104C. A predetermined portion of the pattern and a predetermined portion of the conductive pattern on the bottom 101 b are connected by a bonding wire 103.

  Therefore, in the light emitting device 100 of FIG. 9, one LED element is mounted on one submount, such that the LED element 102A is mounted on one submount 104A. The submounts 104A to 104C are mounted on the reflect case 101, respectively.

In addition, submount 104A-104C can be used as a place which mounts the element for protection of LED element 102A-102C. Further, since the LED elements 102A to 102C are rotated and installed with respect to the submounts 104A to 104C, the light emitted by the LED elements can be uniformly emitted in the vertical and horizontal directions.
JP 2000-286457 A ([0030] to [0034], FIG. 2)

  However, according to the light emitting device shown in Patent Document 1, since the LED elements 102A to 102C are individually mounted on the submounts 104A to 104C, there is a limit to the mounting pitch when mounting a plurality of LED elements 102A to 102C. Therefore, the size reduction cannot be realized, and various characteristics such as reliability and color mixing are inferior.

  An object of the present invention is to provide a light-emitting device which can achieve a narrow pitch even if a plurality of light-emitting elements are used, can be downsized, and has improved various characteristics such as reliability and color mixing.

  In order to achieve the above object, the present invention provides a light-emitting device comprising a plurality of flip-chip light-emitting elements and an intermediate substrate on which the plurality of light-emitting elements are flip-chip mounted.

  According to this configuration, since the plurality of light emitting elements are mounted on the intermediate substrate, the pitch between the light emitting elements can be reduced as compared with the case where the individual light emitting elements are mounted on the individual intermediate substrate.

  In order to achieve the above object, the present invention provides a plurality of flip-chip light emitting elements, an intermediate substrate on which the plurality of light emitting elements are flip-chip mounted, the plurality of light emitting elements and the intermediate substrate. Provided is a light emitting device including a package portion to be stopped.

  According to this configuration, the pitch between the light emitting elements can be narrowed by mounting the plurality of light emitting elements on the intermediate substrate as compared to mounting the individual light emitting elements on the individual intermediate substrate.

  The plurality of light emitting elements preferably include red, green, and blue light emission colors. The light emitting element may emit two-color or single-color emitted light. Further, it is preferable that the plurality of light emitting elements have a parallel circuit configuration and have a protective function. Further, it is preferable that the plurality of light emitting elements are mounted at an arbitrary angle according to a mounting space or the like. Further, as the light emitting element, for example, the LED element is a flip chip type element made of a GaN-based semiconductor compound, or a flip chip type element made of a four-element AlInGaP, and emits red light. Output, high brightness, and high heat dissipation can be expected, and when used in a light-emitting device, high output, high brightness, and high heat dissipation are provided.

  Preferably, the package unit includes a concave reflective case on which the intermediate substrate is mounted and which reflects light emitted from the plurality of light emitting elements in a predetermined direction.

  It is preferable that the intermediate substrate is mounted on the package portion by bonding via a conductive bonding member on the lower surface thereof. For example, bonding by solder, bonding by a bump such as a gold bump or solder bump, or bonding by an adhesive such as a conductive adhesive is used. By using the conductive coupling member, the heat generated from the LED is efficiently radiated to the reflect case 101 and the like, thereby preventing the LED from reaching a high temperature.

  According to the light emitting device of the present invention, the pitch can be reduced even when a plurality of light emitting elements are used, and various characteristics such as downsizing, reliability, and color mixing can be improved.

[First Embodiment]
(Configuration of light emitting device)
FIG. 1 shows a light emitting device according to a first embodiment of the present invention. The light emitting device 1 is mounted on a reflector case 10 as a package part having a rectangular outer shape and having a circular recess 10a at the center of the upper surface, an intermediate substrate 11 made of silicon, and the intermediate substrate 11. The composite LED chip 2 includes a plurality of LED elements 12A, 12B, and 12C as light emitting elements, and is mounted on the bottom 10b of the recess 10a.

  The reflect case 10 is made, for example, by molding a resin or the like, and a concave portion 10a having an inclined inner wall surface is formed at the center, and a reflective layer 10c is formed on the inclined inner wall surface by vapor deposition of aluminum or the like. Further, a conductive pattern (not shown) for connecting the electrode portions of the LED elements 12A to 12C and the outside is formed on the bottom portion 10b. In addition, the package part is not limited to the shape of the illustrated reflective case 10, and can have any shape.

  The intermediate substrate 11 has a conductive pattern (not shown) for connecting the electrode portions of the LED elements 12 </ b> A to 12 </ b> C and an external power supply device or the like inside. The conductive pattern on the intermediate substrate 11 and the conductive pattern in the recess 10 a are connected by a plurality of bonding wires 13.

  The LED elements 12A to 12C are flip chip type elements, and those having different emission colors such as red (R), green (G), and blue (B) are used, but three of them have the same emission color. Alternatively, the three may be divided into two colors. The LED elements 12A to 12C are mounted on the intermediate substrate 11 in a state of being close to each other, that is, with a minimum pitch.

  FIG. 2 shows a cross section taken along line AA of the light emitting device of FIG. A conductive pattern 14 is formed on the bottom 10b of the recess 10a of the reflect case 10, and the intermediate substrate 11 is mounted on the conductive pattern 14 via, for example, a bonding layer 15 bonded with an adhesive. Here, as the adhesive, a conductive adhesive, a high thermal conductive adhesive, or the like can be used.

  A conductive pattern 16 is formed on the intermediate substrate 11, and LED elements 12 </ b> A to 12 </ b> C are mounted on the conductive pattern 16 via bumps 17 made of Au. Note that a p-side electrode 18A and an n-side electrode 18B are provided on the lower surfaces of the LED elements 12A to 12C, and the bumps 17 are connected to these electrodes 18A and 18B. Further, after the LED elements 12A to 12C are mounted in the recess 10a, for example, a sealing member 19 made of a transparent resin is filled. The sealing member 19 may be a transparent resin mixed with a light diffusing agent, a coloring material, or a phosphor.

(Detailed configuration of LED element)
FIG. 3 shows a detailed configuration of the LED element 12A. The LED element 12A is, for example, a flip chip type using a GaN-based semiconductor compound and emits blue light. The LED element 12A includes a p-type GaN layer 20 formed on the p-side electrode 18A, a light-emitting layer 21 that is formed on the p-type GaN layer 20 and emits light when current is injected, and an n-side An n-type GaN layer 22 provided on the electrode 18B and the light emitting layer 21 and an element substrate 23 formed of Al ₂ O ₃ (sapphire) and formed on the n-type GaN layer 22 are provided.

  The LED element 12B is, for example, a flip chip type using a GaN-based semiconductor compound and emits green light. The LED element 12C is a flip chip type using, for example, a four-element AlInGAP compound semiconductor instead of the GaN semiconductor compound, and emits red light.

(Connection status of LED elements)
4 shows the connection of the LED elements 12A to 12C of the light emitting device 1. In FIG. 4, (a) is a connection diagram of only the LED elements 12A to 12C, and (b) is a Zener diode 30A to the LED elements 12A to 12C. It is the connection diagram which connected 30C.

  As shown in FIG. 4A, each of the LED elements 12A to 12C is not connected to the other LED elements but is connected independently. This state is connected to an external connection terminal (not shown) of the reflect case 10. It remains unchanged. Therefore, a circuit configuration desired by the user can be freely constructed. For example, three LED elements 12A to 12C can be connected in parallel to correspond to an anode common circuit, a cathode common circuit, or the like. In addition, the connection configuration of the light emitting elements can be freely selected such that two of the three LED elements 12A to 12C are connected in parallel and one is connected independently.

  FIG. 4B is a diagram in which Zener diodes 30A to 30C are connected in parallel to each LED element 12A to 12C so as to have reverse polarity, and when an excessive voltage is applied to the LED elements 12A to 12C. The excess is absorbed by the Zener diodes 30A to 30C, and the LED elements 12A to 12C can be protected. The Zener diodes 30 </ b> A to 30 </ b> C are mounted on the intermediate substrate 11.

(Operation of light emitting device)
For example, the light emitting device 1 is connected to an external terminal or electrode provided in the reflector case 10 in a state where LED elements 12A to 12C emitting red (R), green (G), and blue (B) are connected in parallel. When power is supplied from the power supply device, a current flows to the LED elements 12A to 12C through the intermediate substrate 11, and the LED elements 12A to 12C are turned on simultaneously. In this case, the emission color of the LED elements 12A to 12C becomes white light due to the mixed color, part of which is emitted directly above the recess 10a, and the other part is reflected by the reflective layer 10c and emitted to the outside. Note that the LED elements 12A to 12C may be turned on simultaneously as described above or individually.

(Method for manufacturing light emitting device)
Next, a method for manufacturing the light emitting device 1 will be described. First, the composite LED chip 2 is fabricated by mounting the LED elements 12A to 12C at predetermined positions on the intermediate substrate 11. Next, the composite LED chip 2 is mounted on the conductive pattern 14 in the recess 10a of the reflect case 10 by bonding with an adhesive. Next, a predetermined portion of the conductive pattern 16 and a predetermined portion on the conductive pattern 14 are connected by the bonding wire 13. Finally, the recess 10a is filled with, for example, a transparent resin, and the sealing member 19 is formed. Thereby, the light-emitting device 1 is completed.

(Effects of the first embodiment)
According to this embodiment, the following effects can be obtained.
(A) Since the LED elements 12A to 12C are mounted on the single intermediate substrate 11, the pitch between the LED elements 12A to 12C can be narrowed, and the light emitting device 1 can be downsized and improved in color mixing. Can be achieved.
(B) Since the connection of the LED elements 12A to 12C is made element-by-element, a plurality of LED elements can be freely connected in parallel, in series, connected in series and parallel, etc., and the restrictions on circuit design and use by the user are reduced. can do.
(C) The LED elements 12A to 12C can be protected by connecting the Zener diodes 30A to 30C to the LED elements 12A to 12C.
(D) By using the flip-chip type LED elements 12A to 12C, it is possible to obtain the light emitting device 1 having high output, high luminance, and high heat dissipation.
(E) The LED elements 12A to 12C can be made wireless, and the reliability can be improved.
(F) When the LED elements 12A to 12C are made of three colors of red, green and blue, since a white emission color is obtained, it can be applied to various backlight light sources, in-vehicle light sources, and the like. When a mixed color is emitted, there is an application as a light source for amusement or illumination. Therefore, the light emitting device 1 that can be used in many fields can be provided.

[Second Embodiment]
FIG. 5 shows a light-emitting device according to the second embodiment of the present invention. The light emitting device 1 is obtained by mounting the LED element 12B on the intermediate substrate 11 at a predetermined angle, for example, 45 degrees with respect to the LED elements 12A and 12C in the first embodiment. The configuration is the same as in the first embodiment. In addition, in FIG. 5, although only the LED element 12B was rotated, you may rotate two or all. Further, the rotation angles may be individually different, or all may be the same angle.

(Effect of the second embodiment)
According to this embodiment, since the LED elements 12A to 12C can be mounted at an arbitrary angle according to the mounting space or the like, the size can be reduced, and the degree of freedom in design and mounting is improved. be able to.

[Third Embodiment]
FIG. 6 shows a light-emitting device according to the third embodiment of the present invention. Moreover, FIG. 7 shows the cross section of the BB line of FIG. In the light emitting device 1, in the first embodiment, a conductive pattern 24 is formed on the lower surface of the intermediate substrate 11, and the intermediate substrate 11 is mounted on the conductive pattern 14 via bumps 25 made of solder. And the conductive pattern 14 are connected, and the other configuration is the same as that of the first embodiment.

(Effect of the third embodiment)
According to this embodiment, since the mounting is performed by the bumps 25 made of solder instead of the formation of the bonding layer 15 to be bonded through the adhesive, the first is used depending on the use or the specification of the production line. One of the embodiments and the present embodiment can be selected. Further, gold bumps may be used in place of the bumps 25 made of solder. Other effects are the same as those of the first embodiment.

[Other embodiments]
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, the combination of the constituent elements between the embodiments can be arbitrarily performed without changing the gist thereof. Further, by mounting the laser diode on the intermediate substrate, the semiconductor laser can be reduced in size, and high output, high reliability, and high heat dissipation can be improved.

1 is a perspective view of a light emitting device according to a first embodiment of the present invention. It is sectional drawing of the AA line of the light-emitting device of FIG. It is sectional drawing which shows the detailed structure of an LED element. The connection of the LED element of the light-emitting device which concerns on the 1st Embodiment of this invention is shown, (a) is a connection diagram of only an LED element, (b) is the connection diagram which connected the Zener diode to the LED element. It is a perspective view which shows the light-emitting device which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the light-emitting device which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the BB line of the light-emitting device of FIG. It is a perspective view which shows the structure of the conventional light-emitting device. It is a perspective view which shows the structure of the other conventional light-emitting device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Composite LED chip 10 Reflection case 10a Recess 10b Bottom 10c Reflective layer 11 Intermediate board 12A, 12B, 12C LED element 13 Bonding wire 14 Conductive pattern 15 Bonding layer 16 Conductive pattern 17 Bump 18A P side electrode 18B N side electrode 19 Sealing member 20 P-type GaN layer 21 Light-emitting layer 22 n-type GaN layer 23 Substrate 24 Conductive pattern 25 Bumps 30A, 30B, 30C Zener diode 100 Light-emitting device 101 Reflective case 101a Recesses 102A, 102B, 102C LED element 103 Bonding wire 104A, 104B, 104C Submount

Claims (6)

A plurality of flip-chip light emitting elements;
A light emitting device comprising: an intermediate substrate on which the plurality of light emitting elements are flip-chip mounted. A plurality of flip-chip light emitting elements;
An intermediate substrate on which the plurality of light emitting elements are flip-chip mounted;
A light-emitting device comprising: a plurality of light-emitting elements and a package unit that accommodates and seals the intermediate substrate.   The light emitting device according to claim 2, wherein the plurality of light emitting elements include red, green, and blue light emission colors.   The light emitting device according to claim 2, wherein the package unit includes a concave reflective case on which the intermediate substrate is mounted and which reflects light emitted from the plurality of light emitting elements in a predetermined direction.   3. The light emitting device according to claim 2, wherein the intermediate substrate is mounted on the package part by bonding via a conductive bonding member on a lower surface thereof.   The light emitting device according to claim 5, wherein the coupling member is a bump.