JP2005167136A - Semiconductor light emitting device and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a package type semiconductor light emitting device which can make thin the structure of a backlight means for liquid crystal display screen. <P>SOLUTION: In the package type semiconductor light emitting device, a metal reflecting plate having an arcuate reflecting surface is joined on a printed circuit board, a light emitting element mounted on the board is packaged with a synthetic resin containing a material having a light conversion function, and the upper surface of the package is covered with a cover member made of resin having a reflecting function material incorporated therein. The light emitting device converts light emitted from the light emission surface of the light emitting element, and emits light reflected by the arcuate reflecting surface of the metal reflecting plate and the cover member from a light emission surface normal to the light emission surface of the light emitting element. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an improvement of a package type semiconductor light emitting device (LED) used as a backlight of a liquid crystal display screen of, for example, a mobile phone or a personal computer, and a manufacturing method thereof.

  In general, many package type light emitting devices used as a backlight in a liquid crystal display device are known. For example, as shown in FIG. 12 and FIG. 13, the package-type light emitting device known in the art has a light guide plate for the light emitting surface of the LED chip, that is, the light emitting element, as is clear from the description of Japanese Patent Application Laid-Open No. 2003-229603. It is comprised so that it may be opposed and used with respect to the end surface of this.

  In addition, in the side light emission type semiconductor light emitting device described in US design US D47887S, a plastic case having a reflection function is formed in advance on a metal lead frame, and the case opening is formed in a recess secured in the case. In order to mount the light emitting device in the horizontal direction with respect to the surface, it is necessary to provide an opening larger than the vertical and horizontal dimensions of the light emitting device, and ensure mechanical strength when forming the prescribed plastic case Therefore, the thickness of the case must be kept above a certain level, and it has been difficult to realize an ultra-thin package.

The conventionally known light emitting device will be described with reference to FIGS.
FIG. 12 shows a cross section of the double-sided light emitting LED package 1 disclosed in the above prior art publication, and the double-sided light emitting LED package 1 is of a type having a pair of LED chips 4 and 4. Reflective cups 5 and 5 for accommodating the LED chips 4 and 4 are formed in the center of the front and back surfaces of the circuit board 2 having an insulating property made of glass epoxy resin or the like having a substantially rectangular shape in plan view.

  The reflection cups 5 and 5 formed on the front and back surfaces of the circuit board 2 include bottom surfaces 5a and 5a and inclined surfaces 5b and 5b, and electrode patterns 7a and 7b are formed so as to divide the plane of the circuit board 2 into two. doing. The LED chips 4 and 4 are flip-chip mounted on the bottom surfaces 5a and 5a of the reflective cup 5 so as to straddle the electrode patterns 7a and 7b, and then the translucent resin as a package body in the mouth of the reflective cups 5 and 5 8 and 8 are filled to form the light emitting surface 9. Note that the bottom surface 5a and the inclined surface 5b of the reflective cup 5 are provided with an Ag or Au plating portion at the time of electrode formation. Moreover, it is also possible to realize a color tone conversion function by mixing a fluorescent agent or the like in the filled light emitting resin 8.

  FIG. 13 shows a partial cross section of the case body when the double-sided light emitting LED package 1 as shown in FIG. 12 is used as a backlight of a mobile phone. An LCD 11 is disposed in a part of the case body 10. A double-sided light emitting LED package is provided between the light guide plate 14 B for the LCD 11 and the light guide plate 14 A for the key switch unit, and the light emitting surface of the LED chip is the light emitting surface. The LCD light guide plate 14 </ b> B and the key switch portion light guide plate 14 </ b> A are provided so as to face each other.

  FIG. 14 is a cross-sectional view for explaining the relationship between an LED and a liquid crystal display portion when a general LED package as described above is used as a backlight for a liquid crystal display surface of a mobile phone or a personal computer, for example. . In the figure, a general liquid crystal display unit is provided with a reflection sheet 16 and a diffusion sheet 17 with a light guide plate 15 interposed therebetween, and a liquid crystal plate (not shown) is installed above the diffusion sheet 17. A prism sheet 18 is interposed between the diffusion sheet 17 and the light guide plate 15.

The package-type semiconductor light-emitting device 20 is provided with an insulating substrate 22 and a light-emitting element 24 at the bottom of a light-shielding synthetic resin case 21 and enclosed by a package body 25. The light-emitting surface 26 of the light-emitting device is the light guide plate. 15 are arranged opposite to the introduction surface 19. Therefore, in such a conventionally known package type semiconductor light emitting device 20, the light emitting surface of the light emitting element 24 and the light emitting surface 26 of the package body 25 are parallel, and the insulating substrate 22 is also parallel to the light introducing surface of the light guide plate 15. It is mounted opposite to.
JP 2003-229603 A JP 2003-258309 A

  In the conventionally known package type semiconductor light emitting device as described above, a semiconductor light emitting device is used to dispose the light emitting surface constituting the end face of the package body and the light introducing surface of the light guide plate for the backlight of the liquid crystal display surface. The light emitting surface of the insulating substrate and the light emitting element constituting the device is installed in parallel with the light emitting surface of the package body, and the width of the light emitting surface of the package body and the thickness of the light introduction surface of the light guide plate, that is, the light guide surface for the backlight. The thickness of the portion constituting the light means is defined by the width of the light emitting element (planar dimension of the semiconductor chip).

Therefore, for example, in a liquid crystal display screen for a mobile phone or a personal computer, it is difficult to make the backlight means thinner.
A first problem of the present invention is to provide a package type semiconductor light emitting device that can improve the above-mentioned problems of the prior art and can make the backlight means thinner. Provided is a package type semiconductor light emitting device in which a light emitting element is mounted in a vertical direction and a reflection wall portion on the upper surface of the package can be manufactured by a resin sealing process.
A second problem is to provide a method for manufacturing a package type semiconductor light emitting device of the above type in a large amount and at a low cost.

In the light emitting device according to the present invention, a metal reflector having an arc-shaped reflecting surface is bonded on a printed circuit board, and the light emitting element mounted on the board is packaged by a synthetic resin containing a light conversion functional material. The upper surface thereof is covered with a cover material made of a reflection functional material mixed resin, converts light emitted from the light emitting surface of the light emitting element, and the light reflected by the arc-shaped reflective surface of the metal reflector and the cover body A package type semiconductor light emitting device which emits light from a light emitting surface perpendicular to the light emitting surface of the light emitting element.
In addition, the metal reflector can have two continuous arc-shaped reflective surfaces, and light emitting elements are mounted at positions corresponding to each of them.
Furthermore, the metal reflector can be made of aluminum blocks.
The manufacturing method according to the present invention is a method for manufacturing a semiconductor light emitting device in which the light emitting surface of the light emitting element and the light emitting surface of the semiconductor light emitting device are orthogonal to each other, and a plurality of holes are formed on the printed circuit board. The plurality of holes constitute a light reflecting surface, and then a plurality of light emitting elements are mounted in the plurality of holes, and a light conversion function material is included thereon. A cover body is formed of a resin filled with a resin and further mixed with a reflective functional material, and then divided into a plurality of semiconductor light emitting devices by dividing at least the hole portion into two. It is a manufacturing method. And the hole drilled in the said metal reflecting disc body contains the manufacturing method characterized by being formed in the substantially bowl shape.

First, since the semiconductor light emitting device of the present invention has a structure capable of emitting light in the lateral direction with respect to the light emitting surface of the light emitting element, the thickness of the light emitting surface can be reduced. The backlight structure can be configured to be extremely thin.
Second, since a metal is used as the material of the reflecting plate that reflects light emitted from the light emitting element, heat generated from the light emitting element can be efficiently radiated to the outside. And because it has better reflection efficiency and better thermal conductivity than conventional plastic reflectors, it can efficiently dissipate the heat generated by the light-emitting element to the outside, and even with a smaller and thinner package structure than the conventional high output The semiconductor light emitting device can be obtained.
According to the method for manufacturing a semiconductor light-emitting device of the present invention, a semiconductor light-emitting device having a light emitting surface in a lateral direction with respect to a light-emitting element generation surface using a metal reflector and a reflective layer that directly covers the upper surface of the package Can be produced in large quantities by an extremely simple process.

Embodiments relating to the package type semiconductor light emitting device of the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view of a semiconductor light emitting device 30 according to the present invention, and FIGS. 2 to 5 are a top view, a front view, a back view, and a cross-sectional view taken along line AA of FIG. Show. As in the case of the conventional package type semiconductor light emitting device as described above, on the printed circuit board 32, for example, two LED packages 31, 31 are connected, and the light emitting elements 34, 34 which are two light emitting elements. Is installed continuously. And the metal electrodes 35a-35d are connected to this light emitting element 34,34 using the wire 40, respectively.

The metal reflector 36, which is one characteristic structure of the present invention, is a metal reflector such as aluminum. In this embodiment, the metal reflector 36 is formed in a block having two arc-shaped reflecting surfaces 36a and 36b. The block-shaped reflector 36 is bonded onto the surface of the printed circuit board 32, and the light emitting elements 34 are arranged on substantially the center of the pair of arc-shaped reflecting surfaces.
2 and 3, the electrodes 35a to 35d formed in advance on the printed circuit board 32 and the electrodes of the light emitting elements 34 and 34 are connected by wires 40 to 40, respectively.

  In the space formed by the upper surface of the printed circuit board 32 on which the light emitting elements 34 and 34 are arranged and the reflection surfaces 36a and 36b of the metal reflector 36, for example, two light emitting elements 34 and 34 arranged are arranged. A package 37 made of a resin mixed with a light conversion functional material is applied so as to be included. The reflection layer 38 covering the upper surface of the package 37 is formed so as to cover the upper surface of the package 37 with a resin mixed with a material having a reflection function.

  In the present invention, a blue light-emitting diode such as InGaN can be used as a light-emitting element, and a phosphor material that can convert yellow or yellow-green + red as a light-conversion functional material can be used. Furthermore, by using a highly reflective material such as titanium oxide as the reflective functional material, a semiconductor light emitting device capable of emitting light in the lateral direction as described later can be obtained.

  FIG. 6 shows the relationship between the semiconductor light emitting device and the backlight mechanism when the semiconductor light emitting device of the present invention is used as a backlight for a liquid crystal display surface of a mobile phone or the like, for example, as shown in FIG. It is a figure demonstrated in contrast with. As in FIG. 14, as the backlight mechanism, a reflection sheet 16 and a diffusion sheet 17 are provided with a light guide plate 15 interposed therebetween, and a prism sheet 18 is provided between the diffusion sheet and the light guide plate 15. Similarly, a light introducing surface 19 is formed in the light introducing portion of the light guide plate 15.

  As described above, the semiconductor light emitting device 30 includes the printed circuit board 32 which is a basic configuration constituting the LED package 31 and the light emitting element 34 mounted on the board. Further, a metal reflector 36 is provided at the rear part of the printed circuit board 32, and the upper surface of the package 37 is covered with a reflection functional material mixed resin 38. Therefore, the light emitted from the upper surface of the light emitting element is converted into, for example, white light by the light conversion functional material constituting the package 37, and at the same time, reflected from, for example, the two arcuate reflecting surfaces 36a, 36b of the metal reflector 36. Almost all the light is emitted from the light emitting surface 39 in the right direction of the package 37 toward the light introducing surface 19 by the functional material mixed resin 38.

  As is apparent from the structure of the semiconductor light emitting device of the present invention, the thickness dimension of the light emitting surface 39 of the package 37 is not limited by the width dimension of the conventional light emitting element, but is determined by the height dimension thereof. The Rukoto. Accordingly, when the comparison between the conventional example and the present invention is examined with reference to FIGS. 6 and 14 with respect to the light guide plate disposed opposite to the light emitting surface, the present light guide plate is more than the thickness T1 of the light guide plate 15 of the conventional example. It can be seen that the thickness T2 of the light guide plate 15 of the invention can be made much thinner.

A method for manufacturing a semiconductor light emitting device according to the present invention will be described with reference to FIGS.
FIG. 7 shows an electrode group formed on the printed circuit board and a plate-like body for a reflector made of, for example, aluminum fixed on the printed circuit board. That is, an aluminum plate 41 described later is bonded onto a printed circuit board 32 having a large number of metal electrodes 34a to 34c for mounting a light emitting element by a generally known method.

  The disc-like body 41 is generally the same as the original size (size before cutting) of the printed circuit board 32, and has a large number of holes, and the holes are recessed in a later process. As well as a package area and a reflective surface. The recesses 42 to 42 are formed by forming a number of substantially bowl-shaped holes in the aluminum plate-like body 41 and bonding them to the printed circuit board 32. Further, in order to mount four light emitting elements 34 to 34 in each one of the recesses 42 to 42, a large number of metal electrodes 34a to 34c are printed at the corresponding positions. The groove indicated by reference numeral 43 in the figure is cut at this position in a later step.

  FIG. 8 shows a state in which the light emitting elements 34 to 34 are mounted at corresponding positions of the recesses 42 to 42 and connected to the corresponding electrodes 34 a to 34 c by wires 44 to 44 following the base state shown in FIG. Show.

  FIG. 9 shows a state where sealing with the conversion function material mixed resin is completed. After mounting the light emitting elements 34 to 34 shown in FIG. 42 is sealed. As described above, the conversion mechanism material mixed resin is, for example, a mixture of materials that convert blue light into yellow or yellow-green + red light, depending on the type of the light-emitting element itself, or to obtain a necessary light color. Are arbitrarily selected.

  FIG. 10 is a view in which after the package state as shown in FIG. 9, the surface of the package made of the conversion functional material mixed resin is sealed with the reflective functional material mixed resin. In other words, the reflective layer 38 is made of a resin mixed with a reflective functional material made of, for example, titanium oxide, and covers the surface of the above-described package 37, and thereby, cooperates with the above-described reflector 36 to produce a light emitting element. The light from 34 can be emitted almost completely to the side.

11 shows a state in which the completed semiconductor light emitting devices 30 to 30 are cut and separated from the disc-shaped product shown in FIG. 10, and the disc-shaped product shown in FIG. It is completed by cutting along.
Therefore, as apparent from FIGS. 7 to 10, two light emitting elements are simultaneously mounted in the numerous recesses 42 to 42 formed in the disc-like body 41, and at the same time the recesses 42 to 42 are mounted. Each wall surface 42 constitutes a reflecting surface 36a, 36b.

  Each of the light emitting devices 30 to 30 cut and separated in this way has the structure shown in FIG. 1. However, such a new side light emitting type semiconductor light emitting device can be produced in a large amount by a simple process. I was able to manufacture it.

1 is a perspective view of a semiconductor light emitting device according to the present invention. FIG. 2 is a top view of the semiconductor light emitting device shown in FIG. 1. It is a front view of the semiconductor light-emitting device shown in FIG. FIG. 2 is a rear view of the semiconductor light emitting device shown in FIG. 1. It is AA sectional drawing of FIG. It is explanatory drawing of the backlight mechanism using the semiconductor light-emitting device of FIG. It is process explanatory drawing of the manufacturing method of the semiconductor light-emitting device based on this invention. It is process explanatory drawing of the manufacturing method of the semiconductor light-emitting device based on this invention. It is process explanatory drawing of the manufacturing method of the semiconductor light-emitting device based on this invention. It is process explanatory drawing of the manufacturing method of the semiconductor light-emitting device based on this invention. It is process explanatory drawing of the manufacturing method of the semiconductor light-emitting device based on this invention. It is sectional drawing of a conventionally well-known semiconductor light-emitting device. It is a partial cross section figure of the backlight mechanism using the semiconductor light-emitting device of FIG. It is explanatory drawing of the backlight mechanism using the conventional semiconductor light-emitting device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 15 Light guide plate 16 Reflective sheet 17 Diffusion sheet 18 Prism sheet 19 Light introduction surface 30 Semiconductor light-emitting device 31 LED package 32 Printed circuit board 34 Light emitting element 35a-35d Metal electrode 36 Metal reflector 36a, 36b Reflective surface 37 Package 38 Reflective layer 39 Light emission Surface 40 wire 41 plate-like body 42 recess

Claims (6)

A metal reflector having an arc-shaped reflecting surface is joined on a printed circuit board, and the light emitting element mounted on the substrate is packaged with a synthetic resin containing a light conversion functional material, and the upper surface is made of a reflective functional material mixed resin. Covered by the cover body, the light emitted from the light emitting surface of the light emitting element is converted, and the light reflected by the arc-shaped reflective surface of the metal reflector and the cover body emits light in a direction perpendicular to the light emitting surface of the light emitting element. A package type semiconductor light emitting device characterized by being emitted from a surface. 2. The package type semiconductor light emitting device according to claim 1, wherein the metal reflecting plate has two continuous arc-shaped reflecting surfaces. 3. The package type semiconductor light emitting device according to claim 2, wherein a light emitting element is mounted at a position corresponding to each of the two continuous arcuate reflecting surfaces. 3. The package type semiconductor light emitting device according to claim 1, wherein the metal reflector has a block shape made of aluminum. A method for manufacturing a semiconductor light emitting device in which a light emitting surface of a light emitting element and a light emitting surface of a semiconductor light emitting device are orthogonal to each other, wherein a metal reflector having a large number of holes formed on a printed circuit board is bonded, These holes constitute a light reflecting surface. Next, a plurality of light emitting elements are mounted in each of the plurality of holes, and a resin containing a light conversion functional material is filled thereon, and further, a reflection is formed thereon. A manufacturing method comprising: forming a cover body with a resin mixed with a functional material, and then cutting and dividing into at least a plurality of semiconductor light emitting devices by dividing the hole portion into two. 5. The method of manufacturing a semiconductor light emitting device according to claim 4, wherein the hole formed in the metal reflector plate is formed in a substantially bowl shape.

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