JP2004087935A - Semiconductor light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor light-emitting device which can improve its generated color dots, when its plurality of color LED chips emit their lights simultaneously as to mix their colors with each other. <P>SOLUTION: LED chips 14a, 14b, 14c are mounted on a board 11. A reflection case 12 is stuck on the board 11. An inclined angle α1 for each first region 13a of reflecting surfaces 13 of the reflection case 12, which is made close to each LED chip 14, is set to a steeper angle (e.g., not smaller than 60°and not larger than 90°) than an inclined angle α2 (e.g., not smaller than 15° and not larger than 60°) of each second region 13b of the reflection surfaces 13. As a result, incidentlights are so projected on the first regions 13a as not to be reflected upward and the colors of the LED chips 14 present respectively at the shortest distances from the respective first regions 13a are weakened partly not to be mixed with each other and to give a uniform color tone. Therefore, by using the LED chips having respectively three primary colors of red, blue, and green, they can be also used as a bright white-color light source having less dots. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor light emitting device on which a plurality of LED (light emitting diode) chips having different emission colors are mounted.
[0002]
[Prior art]
In recent years, the demand for chip-type LEDs for backlights for display screens of mobile phones and for liquid crystal display devices has been growing because the size of packages is small and surface mounting is possible in light of the trend toward miniaturization of electronic products. I have. Also, by increasing the brightness and full color of the LED chip, it is possible to configure a white LED by combining three colors of red, blue and green, and as an alternative light source for an incandescent light bulb (filament light bulb), an amusement device (pachinko or Demand is expanding in all fields, such as pachislot, lighting equipment for vending machines, and traffic lights.
[0003]
FIG. 9 and FIG. 10 show a conventional reflective chip LED. FIG. 9 shows a multicolor chip LED. FIG. 10 shows a single-color chip LED. Each of the chip-type LEDs has a structure in which a resin-made reflection case is attached to a substrate on which an LED chip is mounted.
[0004]
In FIG. 9, FIG. 9A is a plan view. FIG. 9B is a cross-sectional view including one LED chip in FIG. 9A. A reflection case 2 having a conical through-hole with a small diameter on the bottom side and a large diameter on the front side is laminated on the substrate 1. The wall of the through-hole of the reflection case 2 is formed with the top surface of the substrate 1 as the bottom surface. A cup is formed as a wall. Then, three LED chips 4a, 4b, 4c are mounted on the bottom surface (the upper surface of the substrate 1) in the cup, and a sealing resin (epoxy resin) 5 is filled in the cup. Thus, the LED chips 4a, 4b, 4c are protected by the sealing resin 5. Each LED chip 4 is provided with an electric wiring (not shown). Further, the wall surface of the cup functions as the reflection surface 3.
[0005]
The multi-color type chip LED having the above configuration operates as follows. That is, a part of the light emitted from each of the LED chips 4a, 4b, 4c is directly radiated upward in the drawing. The other emitted light is reflected by the reflection surface 3 of the reflection case 2 and emitted upward.
[0006]
10A is a plan view, and FIG. 10B is a cross-sectional view including an LED chip. The single-color chip LED differs from the multi-color chip LED shown in FIG. 9 in that the number of LED chips is three, but the number of LED chips is one. Is the same. In the case of a monochromatic chip LED, a part of the light emitted from the LED chip 9 is directly radiated upward in the drawing. The other emitted light is reflected by the reflection surface 8 of the reflection case 7 and emitted upward. Incidentally, reference numeral 6 denotes a substrate, and reference numeral 10 denotes a sealing resin.
[0007]
[Problems to be solved by the invention]
However, the above-described conventional multi-color chip LED has the following problems. That is, when the three-color LED chips 4a, 4b, and 4c emit light at the same time, the color mixing state becomes an important problem. However, as shown in FIG. 9, in the reflection type chip type LED in which the LED chips 4a, 4b, 4c of three colors are arranged, the reflection surface 3 of the reflection surface 3 which is close to the respective LED chips 4a, 4b, 4c. Does not receive light from the plurality of LED chips 4a, 4b, 4c, and no color mixing occurs. Therefore, the color of the LED chip 4 located at the shortest comes out strongly. As a result, when the three-color LED chips 4a, 4b, and 4c emit light simultaneously, a target light emission color cannot be obtained, and color tone unevenness due to the separated colors occurs.
[0008]
In particular, when the sealing resin 5 is filled in the cup of the reflection case 2 and the surface of the sealing resin 5 is made convex to have a lens effect, the above-described phenomenon tends to appear significantly. .
[0009]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor light emitting device capable of improving uneven color tone at the time of mixing colors in which LED chips of a plurality of colors emit light simultaneously.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a semiconductor light emitting device according to the present invention includes a plurality of light emitting diode chips having different emission colors, and a reflecting surface for reflecting light emitted in one direction toward a plurality of light emitting diode chips close to each light emitting diode chip. It comprises a first region and a plurality of second regions other than the first region. The first region reflects light from the nearest light emitting diode chip in a direction other than the one direction.
[0011]
According to the configuration, when the plurality of LED chips emit light at the same time, the amount of reflected light in the one direction from the first region where color mixing does not occur is reduced, and the emission color of the LED chip at the shortest position is reduced. Can be weakened. Thus, a uniform color tone can be obtained.
[0012]
That is, by using three primary color LED chips of red, blue, and green as the above-described LED chips, white light that is bright and has less color tone unevenness can be obtained, and can be used as a white light source that is bright and has less color tone unevenness. Further, even when two LED chips or four or more LED chips are mounted, color tone unevenness due to color mixture is small, and a target emission color can be easily obtained.
[0013]
Further, in the semiconductor light emitting device of one embodiment, the same number of the first regions on the reflection surface as the number of the LED chips are provided at positions facing the LED chips.
[0014]
In this case, since only the light emitted from each LED chip is reflected, the amount of reflected light in one direction in the reflection region where color mixing does not occur is effectively reduced.
[0015]
In the semiconductor light emitting device of one embodiment, the inclination angle of the first region on the reflection surface is set to be smaller than the inclination angle of the second region that reflects light from the LED chip located closest to the one direction. Is also bigger.
[0016]
In this case, light from the LED chip located closest to the first region is reflected by the first region in a direction other than the one direction. Thus, the amount of reflected light from the first region where color mixing does not occur in one direction is reduced.
[0017]
In one embodiment, the inclination angle of the first region is set to be larger than 60 degrees and 90 degrees or less, and the inclination angle of the second region is set to 15 degrees or more and 60 degrees or less. ing.
[0018]
In this case, light from the LED chip closest to the first area is reflected by the first area in a direction other than the one direction. Further, light incident on the second region is reflected by the second region in the one direction.
[0019]
Further, in the semiconductor light emitting device of one embodiment, at least the first region on the reflection surface is roughened.
[0020]
In this case, the radiated light from the LED chip located closest to the first area is scattered by the rough first area. Thus, the amount of reflected light from the first region where color mixing does not occur in one direction is reduced.
[0021]
Further, in the semiconductor light emitting device of one embodiment, a concave portion is formed on the surface of the reflective case, the plurality of LED chips are mounted on the bottom surface of the concave portion, and the wall surface of the concave portion serves as the reflective surface. The recess is filled with a sealing resin.
[0022]
In this case, the LED chip mounted on the bottom surface of the recess is protected by the sealing resin.
[0023]
In the semiconductor light emitting device of one embodiment, a light scattering material is added to the transparent sealing resin filled in the recess.
[0024]
In this case, the light emitted from each of the LED chips is scattered in all directions by the light scattering material in the resin. In this way, there is no region where color mixing does not occur because only light from a specific LED chip is reflected in the one direction from the reflective surface. Therefore, a more uniform color tone can be obtained when the plurality of LED chips emit light simultaneously.
[0025]
Further, in the semiconductor light emitting device of one embodiment, the surface of the sealing resin has the same surface as the surface of the reflection case and is flat.
[0026]
In this case, as in the case where the surface of the sealing resin is made convex to have a lens effect, the emphasis on color unevenness due to the separated colors is suppressed. Therefore, a target emission color can be easily obtained.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
[0028]
・ First embodiment
FIG. 1 is a plan view (FIG. 1A) of the semiconductor light emitting device of the present embodiment and a cross-sectional view taken along the line AA ′ in the above plan view (FIG. 1B). This semiconductor light emitting device is a reflection type multi-color chip LED having a structure in which a resin reflection case is attached to a substrate on which an LED chip is mounted, as in FIG.
[0029]
In FIG. 1, a reflective case 12 having a through hole with a small diameter on the bottom surface and a large diameter on the surface side is laminated on a substrate 11, and the upper surface (front surface) of the substrate 11 serves as a bottom surface and the above-described through hole of the reflective case 12 is formed. A cup having the wall of the hole as a wall surface is formed. Then, three LED chips 14a, 14b, and 14c are mounted on the bottom surface of the cup (the upper surface of the substrate 11).
[0030]
Here, the reflection surface 13 formed by the wall surface of the cup is divided into three first regions 13a and other second regions 13b close to the respective LED chips 14a, 14b, 14c. Then, in each of the second regions 13b, light from all the LED chips 14a, 14b, and 14c is incident, and color mixing occurs. Therefore, the inclination angle α2 of each second region 13b with respect to the upper surface of the substrate 11 is an angle at which light from each of the LED chips 14a, 14b, and 14c can be reflected upward in the drawing (for example, 15 degrees) as in the conventional case. (Not less than 60 degrees).
[0031]
On the other hand, in each of the first regions 13a, light from all of the LED chips 14a, 14b, and 14c does not enter, and color mixing does not occur. Therefore, the inclination angle α1 of each first region 13a with respect to the upper surface of the substrate 11 is set to be steeper than the inclination angle α2 of the second region 13b (for example, greater than 60 degrees and equal to or less than 90 degrees) and is closest to each other. The light from the LED chip 14 (14b in FIG. 1B) is not reflected upward. By doing so, the emission color of the LED chip 14 located at the shortest position in the first region 13a is weakened. As a result, when the three color LED chips 14a, 14b, and 14c emit light simultaneously, a uniform color tone is obtained as a whole. Thus, a target emission color can be obtained.
[0032]
Thus, in the present embodiment, the inclination angle α1 of each first region 13a and the inclination angle α2 of each second region 13b are significantly different. Therefore, a step is formed at the boundary between the first area 13a and the second area 13b on the reflection surface 13.
[0033]
A metal wiring pattern 15 is formed on the surface of the substrate 11, and the tip is exposed in the cup, and a metal back pattern 16 is formed on the back. The metal wiring pattern 15 and the back pattern 16 are electrically connected by a metal wiring 17 penetrating the substrate 11. In each LED chip 14 (14b in FIG. 1B), one electrode (not shown) is bonded and fixed to the exposed portion of one metal wiring pattern 15a by Ag paste, and the other electrode (not shown). ) Is mechanically and electrically connected to the exposed portion of the other metal wiring pattern 15b by a gold wire 18.
[0034]
The cup is filled with a sealing resin (epoxy resin) 19. Thus, the LED chips 14a, 14b, 14c are protected by the sealing resin 19.
[0035]
The multi-color type chip LED having the above configuration operates as follows. That is, a part of the light from each of the LED chips 14a, 14b, 14c is directly radiated upward. Other light is reflected by the reflection surface 13 of the reflection case 12. At this time, light from all the LED chips 14a, 14b, and 14c is incident on each of the second regions 13b of the reflection surface 13, and color mixing occurs.
[0036]
On the other hand, in each of the first areas 13a of the reflection surface 13, light from all the LED chips 14a, 14b, and 14c does not enter, and color mixing does not occur. Therefore, the color of the LED chip 14 located at the shortest position (the LED chip 14b in FIG. 1B) becomes strong. However, the inclination angle α1 of each first region 13a is set to, for example, greater than 60 degrees and equal to or less than 90 degrees, and the light from the LED chip 14 (14b) that is closest is directed upward (that is, outside). No reflection). Therefore, the emission color of the LED chip 14 located at the shortest position in the first region 13a is weakened, and a uniform color tone is obtained as a whole.
[0037]
At this time, the surface of the sealing resin 19 is flat, and forms the same plane as the surface of the reflection case 12. Therefore, it is possible to suppress the color tone unevenness due to the separated colors from being emphasized as in the case where the surface of the sealing resin 19 is made convex to have a lens effect. Therefore, a target emission color can be easily obtained.
[0038]
The multi-color chip LED having the above configuration is formed as follows. That is, in FIG. 2, the metal wiring pattern 15 and the back surface pattern 16 (both shown in FIG. 1) are formed on the front and back of the substrate 11, and the metal wiring 17 formed in the through hole (see FIG. 1). Are electrically connected by Each of the LED chips 14 is arranged in a matrix in units of three (represented by one in FIG. 2), and as described above, the Ag paste (not shown) and the gold wire 18 (FIG. 1) Connection). On the other hand, the cups 21 are formed on the resin-made reflecting plate 20 in a matrix so as to correspond to the mounting positions of the LED chips 14.
[0039]
Then, the reflection plate 20 is laminated on the substrate 11 and bonded with an adhesive, and after the adhesive is cured, it is cut by a dicing cutter along the lines a1 to a6 and the lines b1 to b4 including the through holes. Thus, one semiconductor light emitting device having the structure as shown in FIG. 1 is obtained.
[0040]
As described above, in the present embodiment, the reflection surface 13 of the reflection case 12 bonded to the substrate 11 on which the LED chip 14 is mounted has three positions near the LED chips 14a, 14b, and 14c. A first region 13a is provided. The inclination angle α1 of the first region 13a is set to be steeper (for example, greater than 60 degrees and less than 90 degrees) than the inclination angle α2 of the other second regions 13b (for example, 15 degrees or more and 60 degrees or less). ing. Therefore, the light that has entered the first region 13a from the LED chip 14 that is closest to the LED chip 14 does not reflect upward.
[0041]
As a result, the amount of light reflected upward from the first region 13a where color mixing does not occur is reduced, the emission color of the LED chip 14 at the shortest position is weakened, and a uniform color tone is obtained. Therefore, by configuring an LED display using a large number of chip-type LEDs in the present embodiment, it is possible to provide a screen with a uniform color tone. Further, as a light source alternative to the conventional incandescent light bulb (filament light bulb), a light source having a long life (10 times or more) and being resistant to mechanical vibration stress can be provided.
[0042]
Further, by using three primary color LED chips of red, blue and green light as the respective LED chips 14a, 14b and 14c, it is possible to obtain white light which is bright and has little color unevenness, and is a white light source which is bright and has little color unevenness. It can be used as By using this light source as a backlight light source for a liquid crystal display, it is possible to provide a light source that is resistant to vibration and has a long life of 50,000 hours with respect to a cold cathode tube having a life of 2,000 hours. Further, by securing the three primary colors of light, it is possible to realize a liquid crystal display closer to a natural color that is more vivid than the cold cathode tube.
[0043]
In the above-described embodiment, a multi-color type chip LED having three LED chips is described as an example. However, two LEDs such as red and blue, blue and green, and red and green are used. A chip or four or more LED chips may be mounted. Even in that case, the target emission color can be obtained with less color tone unevenness due to color mixture.
[0044]
As described above, in the present embodiment, the various effects described above can be obtained by preventing the light reflected by the first region 13a on the reflection surface 13 from being emitted upward to the substrate 11. . The configuration for preventing the light reflected by the first region 13a from being emitted upward is not limited to the change in the inclination angle α1. Hereinafter, another modified example in which the reflected light from the first region 13a is not emitted upward will be described.
[0045]
3 and 4 are simplified representations of a cross-sectional view corresponding to FIG. In FIG. 3, a reflection case 26 made of resin and having a conical through hole with a small diameter on the bottom side and a large diameter on the front side is laminated on the substrate 25, and the reflection case is formed with the top surface of the substrate 25 as the bottom surface. A cup having the wall of the through hole 26 as a wall is formed. Then, the reflection surface 27 formed by the wall surface of the cup is roughened so that the light incident on the reflection surface 27 is scattered in all directions so that the light is not emitted upward in the drawing. This makes it possible to weaken the emission color of the LED chip 28 in a region of the reflection surface 27 close to each LED chip 28, and to obtain a uniform color tone as a whole. In addition, 29 is a sealing resin.
[0046]
In that case, the roughening of the reflection surface 27 may be performed over the entire circumference, or may be performed only in a region close to each LED chip 28. As a method for roughening the reflection surface 27, (1) resin etching is performed on the reflection surface 27. (2) The reflecting surface portion of the resin molding die is roughened to form the reflecting surface 27 with resin. (3) A white resin is applied to the reflection surface 27, and irregularities are formed on the surface of the white resin. And so on.
[0047]
In FIG. 4, a reflection case 32 made of resin and having a conical through hole with a small diameter on the bottom surface and a large diameter on the surface side is laminated on the substrate 31, and the upper surface of the substrate 31 is used as the bottom surface. A cup having the wall of the through hole of the reflection case 32 as a wall surface is formed. A plurality of LED chips 33 (represented by one) are mounted on a bottom surface in the cup, and a sealing resin 34 is filled in the cup.
[0048]
A scattering material (not shown) such as silica that scatters light is mixed in the sealing resin 34. Therefore, the light emitted from each LED chip 33 is scattered in all directions by the scattering material in the sealing resin 34 and is not emitted upward. Therefore, the light emission color of the LED chip 33 in the region near each LED chip 33 on the reflection surface 35 formed by the wall surface of the cup can be reduced, and a uniform color tone can be obtained as a whole.
[0049]
・ Second embodiment
FIG. 5 is a plan view (FIG. 5A) of the semiconductor light emitting device of the present embodiment, and a cross-sectional view taken along the line BB ′ (FIG. 5B) in the plan view. This semiconductor light emitting device is a reflective multicolor type chip LED in which a lead on which an LED chip is mounted is fixed by a reflective case.
[0050]
On the front side of the resin-made reflection case 41, a hole having a small diameter on the inner side and a large diameter on the front side is formed, and the hole forms a cup. Two leads 42 are inserted into the two side surfaces facing each other, and one end of each lead 42 is exposed on the bottom surface of the cup. The intermediate portion of each lead 42 is bent along the side wall of the reflective case 41, and the other end extends along the back surface of the reflective case 41. That is, the lead 42 is J-formed for surface mounting. One of three LED chips 43a, 43b, 43c is mounted on one end of each lead 42 exposed in the cup.
[0051]
Here, as in the case of FIG. 1 in the first embodiment, the reflection surface 44 formed by the wall surface of the cup has three first regions 44 a close to each LED chip 43 and another second region 44 b. And is divided into: The angle of inclination α2 of each second region 44b where color mixing occurs is set to an angle (for example, 15 degrees or more and 60 degrees or less) at which light from each LED chip 43 can be reflected upward in the figure. . On the other hand, the inclination angle α1 of each first region 44a where color mixing does not occur is an angle at which light from the LED chip 43 (43b in FIG. 5B) which is closest to the first region 44a is not reflected upward (for example, (Greater than 60 degrees and less than 90 degrees).
[0052]
In each LED chip 43 (43b in FIG. 5B), one electrode (not shown) is bonded and fixed to the one end of one lead 42a by the Ag paste, and the other electrode (not shown). (Not shown) is connected to the one end of the other lead 42b by a gold wire 45, and is mechanically and electrically connected. Further, a sealing resin (epoxy resin) 46 is filled in the cup. Thus, the LED chip 43 is protected by the sealing resin 46.
[0053]
At this time, the surface of the sealing resin 46 is flat and forms the same plane as the surface of the reflection case 41. Therefore, it is possible to suppress the emphasis of the color unevenness due to the separated colors as in the case where the surface of the sealing resin 46 is made convex to have a lens effect. Therefore, a target emission color can be easily obtained.
[0054]
The multi-color chip LED having the above configuration is formed as follows. That is, a metal plate is stamped out with a mold to form a lead frame 47 having a shape as shown in FIG. The lead frame 47 has a shape in which four leads 42 extending in opposite directions from positions facing each other are connected by tie bars 48 and arranged in a matrix as shown in FIG. ing. Then, as described above, the LED chip 43 (see FIG. 5) is attached to the tips of the four leads 42 extending in opposite directions from the positions facing each other by the Ag paste and the gold wire 45 (see FIG. 5). Connection is fixed. Further, the reflection case 41 is formed of resin so that the periphery of the LED chip 43 is surrounded by the cup 49. After that, all the leads 42 are cut off from the connection portions to the tie bars 48 and separated into individual semiconductor light emitting elements, and the portions of the leads 42 exposed from the reflection case 41 are bent as shown in FIG. 5B. . Thus, one semiconductor light emitting device having the structure as shown in FIG. 5 is obtained.
[0055]
As described above, in the present embodiment, the cup is formed on the front side of the reflective case 41, and one end of the lead 42 inserted two by two from two opposing side surfaces is attached to the bottom surface of the cup. It is exposed. One of the three LED chips 43a, 43b, and 43c is mounted on one end of each lead 42, and the reflecting surface 44, which is a wall surface of the cup, is provided with the LED chip 43a of the first embodiment. Similarly to the case, the first region 44a where the inclination angle α1 is set to be greater than 60 degrees and equal to or less than 90 degrees and no color mixture occurs, and the color mixture where the inclination angle α2 is set to be equal to or more than 15 degrees and equal to or less than 60 degrees, for example. And a second region 44b where the occurrence occurs.
[0056]
As a result, the amount of light reflected upward from the first region 44a where color mixing does not occur is reduced, the emission color of the LED chip 43 at the shortest position is weakened, and a uniform color tone is obtained. Therefore, by configuring an LED display using a large number of chip-type LEDs in the present embodiment, it is possible to provide a screen with a uniform color tone. Furthermore, as an alternative light source to a conventional incandescent light bulb (filament light bulb), a light source having a long life (10 times or more) and being resistant to mechanical vibration stress can be provided.
[0057]
By using LED chips of three primary colors of red, blue, and green as the LED chips 43a, 43b, and 43c, bright white light with less color tone unevenness can be obtained. That is, the three-color red, blue, and green chip-type LED according to the present embodiment can be used as a white light source that is bright and has less color tone unevenness.
[0058]
Also in the case of the present embodiment, as another configuration for reducing the amount of reflected light upward from the first region 44a to weaken the emission color of the LED chip 43 at the shortest position and obtaining a uniform color tone, the reflection surface A light scattering material can be applied to the surface roughening and sealing resin. Here, the roughening of the reflection surface includes resin etching, resin molding using a mold having a roughened reflection surface portion, and formation of irregularities on the applied white resin surface. The roughening of the reflection surface may be performed over the entire circumference, or may be performed only on a region close to each LED chip 43.
[0059]
・ Third embodiment
FIG. 7 is a plan view (FIG. 7A) of the semiconductor light emitting device of the present embodiment and a cross-sectional view taken along the line CC ′ in the plan view (FIG. 7B). This semiconductor light emitting device is a reflective multicolor type chip LED having a structure generally called an MID (injection molded circuit component).
[0060]
The resin reflection case 51 has a hole with a small diameter on the inner side and a large diameter on the front side, and the hole forms a cup. The metal wiring pattern 52 is formed on the surface of the reflection case 51 including the reflection surface 53 formed by the wall surface of the cup by resin plating or the like, and the metal wiring pattern 54 is also formed on the back surface of the reflection case 51. The two metal wiring patterns 52 and 54 are electrically connected by a metal wiring 55 formed in a through hole 51a (1/4 is shown) provided in advance when the reflection case 51 is molded with resin. I have.
[0061]
The LED chip 56a is mounted on the metal wiring pattern 52a on the bottom surface of the cup in the reflection case 51, the LED chip 56b is mounted on the metal wiring pattern 52b, and the LED chip 56c is mounted on the metal wiring pattern 52c. Each of the LED chips 56 (56b in FIG. 7B) has one electrode (not shown) bonded and fixed to one metal wiring pattern 52b with an Ag paste, and the other electrode (not shown). Are mechanically and electrically connected to another metal wiring pattern 52d by a gold wire 57.
[0062]
The entire surface of the reflection surface 53 of the reflection case 51 or only the region close to each LED chip 56 is etched to roughen the surface. Therefore, the metal wiring pattern 52 formed by plating on the reflection surface 53 is also roughened, and in each region where color mixing does not occur in the vicinity of each LED chip 56, the LED chip 56 closest to the LED chip 56 Is not reflected upward in the figure. Therefore, the emission color of the LED chip 56 located at the shortest position in the above-described region is weakened, and a uniform color tone is obtained as a whole.
[0063]
Further, a sealing resin (epoxy resin) 58 is filled in the cup. Thus, the LED chip 56 is protected by the sealing resin 58. Note that the surface of the sealing resin 58 may be recessed or the same as the surface of the reflection case 51. If it is made convex, the directivity is improved by the action of the convex lens, but it is not preferable because the color tone unevenness due to the separated colors is emphasized and the phenomenon that the target emission color cannot be obtained becomes remarkable. In addition, if the shape is concave, the reflection surface 53 may be exposed, which is not preferable. Therefore, in order to improve color mixing, it is most preferable that the surface of the sealing resin 58 be flush with the surface of the reflection case 51.
[0064]
FIG. 8 is a diagram showing the shape of the MID substrate to be put into the manufacturing process of the reflective multicolor chip LED shown in FIG. Also in this case, a plurality of chip type LEDs are arranged in a matrix.
[0065]
As described above, in the present embodiment, the cup is formed on the front side of the reflection case 51, and the reflection surface 53, which is a wall surface of the cup, is roughened by etching. A metal wiring pattern 52 is formed on the surface of the reflection case 51 including the surface of the reflection surface 53 by plating, and one of the three LED chips 56 is mounted on each metal wiring pattern 52. .
[0066]
Therefore, the surface of the metal wiring pattern 52 is roughened on the reflection surface 53, and the amount of light reflected upward from a region where color mixing does not occur is reduced, so that the emission color of the LED chip 56 at the shortest position is weakened. Thus, a uniform color tone can be obtained. As a result, a screen having a uniform color tone can be provided by configuring an LED display using a large number of chip-type LEDs in the present embodiment. Furthermore, as an alternative light source to a conventional incandescent light bulb (filament light bulb), a light source having a long life (10 times or more) and being resistant to mechanical vibration stress can be provided.
[0067]
In addition, by using LED chips of three primary colors of red, blue, and green as the LED chips 56a, 56b, and 56c, bright white light with less color tone unevenness can be obtained. That is, the three-color red, blue, and green chip-type LED according to the present embodiment can be used as a white light source that is bright and has less color tone unevenness.
[0068]
The roughening of the reflection surface 53 in the present embodiment is not limited to the etching. For example, irregularities may be formed on the surface of the white resin applied to the reflection surface 53.
[0069]
Also in the case of the present embodiment, as another configuration for reducing the amount of reflected light upward from the first region to weaken the emission color of the LED chip 56 at the shortest position and obtaining a uniform color tone, the sealing resin 58 May be mixed with a light scattering material. In that case, fused silica or calcium carbide is suitable as the scattering material to be mixed. In particular, those having a particle size of about 1.5 μm are suitable. Thus, if the scattering material is filled in the sealing resin 58, the color mixing property can be further improved.
[0070]
【The invention's effect】
As is clear from the above, the semiconductor light emitting device of the present invention has a plurality of reflective surfaces that reflect light emitted from a plurality of LED chips having different emission colors in one direction, and a plurality of reflective surfaces close to the respective LED chips. Since the first region reflects light from the LED chip located at the shortest position in a direction other than the one direction, reflection from the first region in the one direction in which color mixing does not occur during simultaneous light emission. The amount of light can be reduced. Therefore, the emission color of the LED chip located at the shortest position in the first region can be reduced, and a uniform color tone can be obtained.
[0071]
That is, according to the present invention, by using three primary color LED chips of red, blue, and green as the respective LED chips, it is possible to obtain white light which is bright and has less color tone unevenness, and is used as a white light source which is bright and has less color tone unevenness. Can be used. Furthermore, even when two LED chips or four or more LED chips are mounted, a target emission color can be easily obtained by reducing color tone unevenness due to color mixture.
[0072]
As described above, according to the semiconductor light emitting device of the present invention, a uniform color tone can be obtained during simultaneous light emission. Therefore, a screen having a uniform color tone can be provided by configuring an LED display by using a large number of the semiconductor light emitting devices. Furthermore, as an alternative light source to a conventional incandescent light bulb (filament light bulb), a light source having a long life (10 times or more) and being resistant to mechanical vibration stress can be provided. Furthermore, a bright white light source with a long life resistant to vibration (50,000 hours compared to the current 2000 hours life of a cold cathode fluorescent lamp) and less color tone unevenness can be provided as a backlight light source for a liquid crystal display. In that case, by securing the three primary colors of light, it is possible to provide a liquid crystal display closer to a natural color that is more vivid than a cold-cathode tube.
[Brief description of the drawings]
FIG. 1 is a plan view and a cross-sectional view of a semiconductor light emitting device of the present invention.
FIG. 2 is an explanatory diagram of a method for forming the semiconductor light emitting device shown in FIG.
FIG. 3 is an explanatory view of a modification of the semiconductor light emitting device shown in FIG.
FIG. 4 is an explanatory diagram of a modified example different from FIG.
FIG. 5 is a plan view and a cross-sectional view of a semiconductor light emitting device different from FIG.
FIG. 6 is an explanatory diagram of a method for forming the semiconductor light emitting device shown in FIG.
FIG. 7 is a plan view and a cross-sectional view of a semiconductor light emitting device different from FIGS. 1 and 5;
8 is an explanatory diagram of a method for forming the semiconductor light emitting device shown in FIG.
FIG. 9 is a plan view and a cross-sectional view of a conventional multicolor chip LED.
FIG. 10 is a plan view and a cross-sectional view of a conventional single-color type chip LED.
[Explanation of symbols]
11, 25, 31 ... substrate,
12, 26, 32, 41, 51 ... reflective case,
13, 27, 35, 44, 53 ... reflective surface,
13a, 44a ... first area,
13b, 44b ... second area,
14, 28, 33, 43, 56 ... LED chip,
15, 52, 54 ... metal wiring pattern,
16 ... Backside pattern,
17, 55 ... metal wiring,
18, 45, 57 ... gold wire,
19, 29, 34, 46, 58 ... sealing resin,
20 ... Reflector,
21,49… cup,
42 ... lead,
47 Lead frame.

Claims (8)

In a semiconductor light emitting device having a reflecting surface that reflects light emitted from a plurality of light emitting diode chips having different emission colors in one direction,
The reflection surface includes a plurality of first regions adjacent to each light emitting diode chip, and a plurality of second regions other than the first regions,
The semiconductor light emitting device according to claim 1, wherein the first region on the reflection surface reflects light from the nearest light emitting diode chip in a direction other than the one direction. The semiconductor light emitting device according to claim 1,
The semiconductor light emitting device according to claim 1, wherein the first region on the reflection surface is provided at a position facing the light emitting diode chip by the same number as the number of the light emitting diode chips. The semiconductor light emitting device according to claim 1,
The semiconductor light emitting device according to claim 1, wherein an inclination angle of the first region with respect to the mounting surface of the light emitting diode chip in the reflection surface is larger than an inclination angle of the second region with respect to the mounting surface. The semiconductor light emitting device according to claim 3,
An inclination angle of the first region is greater than 60 degrees and equal to or less than 90 degrees;
The semiconductor light emitting device according to claim 1, wherein an inclination angle of the second region is not less than 15 degrees and not more than 60 degrees. The semiconductor light emitting device according to claim 1,
A semiconductor light emitting device, wherein at least a first region in the reflection surface is roughened. The semiconductor light emitting device according to claim 1,
A reflective case having a concave portion having a bottom surface on which the light emitting diode chip is mounted and a wall surface formed of the reflective surface,
A semiconductor light emitting device, wherein the recess is filled with a transparent sealing resin and the light emitting diode chip is sealed with a resin. The semiconductor light emitting device according to claim 6,
A semiconductor light emitting device, wherein a light scattering material is added to the sealing resin. The semiconductor light emitting device according to claim 6,
A semiconductor light-emitting device, wherein a surface of the sealing resin forms the same plane as a surface of the reflection case and is flat.

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