JP2001332766A - Side plane luminous semiconductor light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve luminous efficiency to a desired light emission direction. SOLUTION: A side plane luminous semiconductor light-emitting device 10 includes a substrate 12, and a case 14 that is formed by resin having opaque and reflecting properties is provided on the substrate 12. Also, a transparent resin 16 is filled between the substrate 12 and case 14. On the surface of the substrate 12, electrodes 18a and 18b are formed. On the electrode 18a, an LED- chip 20 is die-bonded by DB paste 24. Also, the electrode 18b is electrically connected to the LED chip 20 by a bonding wire 22. Concretely, the LED chip 20 is shifted to the side plane of a light emission surface 16a to the application position of the DB paste 24 for mounting, thus preventing a surface at the side plane of the light emission surface 16a of the LED chip 20 from being covered with the DB paste 24. More specifically, light that is outputted in a desired light emission direction P is not blocked by the DB paste 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side-emitting semiconductor light emitting device, and more particularly to a side-emitting semiconductor light emitting device in which, for example, an LED chip having a transparent base and a light emitting layer thereon is bonded to an electrode on a substrate.

[0002]

2. Description of the Related Art As shown in FIG. 8A, a conventional side-emitting semiconductor light-emitting device 1 of this type includes a substrate 2, and the substrate 2 is formed of an opaque and reflective resin. A reflector (case) 3 is provided. Further, a space between the substrate 2 and the case 3 is filled with a translucent resin 4 such as an epoxy resin. A lead (electrode) 2 is provided on the surface of the substrate 2.
a and 2b are formed, and a semiconductor light emitting element (LED chip) 5 is bonded to the electrodes 2a and 2b. Specifically, as shown in FIGS. 8A and 8B, the LED chip 5 is die-bonded to the electrode 2a with a bonding paste (DB paste) 6 such as a silver paste, and the electrode 2b is connected to the LED chip. 5 are electrically connected by a bonding wire 7 such as a gold wire. In FIG. 8A, the DB paste 6 is omitted for easy understanding. FIG.
As can be seen from FIG. 8A and FIG. 8B, the LED chip 5 is die-bonded almost to the center of the
The case 3 is provided so as to surround the D chip 5, and the LED chip 5 is sealed with the translucent resin 4. Therefore, in the side-emitting semiconductor light emitting device 1, light was output from the side surface provided perpendicular to the substrate 2. That is, the surface 4a, the surface 4b formed of the translucent resin 4, and the surface parallel to the surface 4b and continuous with the surface 4a were the light emitting surfaces.

[0003]

However, in this prior art, since the LED chip 5 is die-bonded on the electrode 2a with the DB paste 6, the lower part of the LED chip 5 is formed.
(Base) was covered with DB paste 6. For this reason, light output from the base portion of the LED chip 5 through the surface 4 a in a desired light emitting direction is transmitted to the DB paste 6.
Had been blocked by. That is, the luminous efficiency was poor.

[0004] Therefore, a main object of the present invention is to provide a side-emitting semiconductor light emitting device capable of improving the light emitting efficiency in a desired light emitting direction.

[0005]

SUMMARY OF THE INVENTION The present invention is a side-emitting semiconductor light-emitting device in which an LED chip having a transparent base and a light-emitting layer thereon is bonded to an electrode on a substrate,
This is a side-emitting semiconductor light emitting device in which the mounting position of the LED chip is shifted to the light emitting surface side with respect to the application position of the bonding paste.

[0006]

In the side-emitting semiconductor light emitting device of the present invention, a semiconductor light emitting element (LED chip) is bonded to an electrode formed on the surface of the substrate. In this LED chip, a light emitting layer is formed on a transparent base. Note that another electrode layer is formed over the light emitting layer. In this side-emitting semiconductor light emitting device, the LED chip is mounted so as to be shifted to the light emitting surface side with respect to the application position where the DB paste is applied. In other words, the LED chips are shifted in a desired light emitting direction. Therefore, it is possible to reduce the amount of DB paste covering the desired light emitting direction side of the LED chip. For this reason,
The light output from the LED chip in the desired light emitting direction is DB
It is not blocked by the paste.

[0007] For example, the electrode formed on the upper surface of the substrate includes an application area for applying the DB paste. Since the application area has a center shifted in the direction opposite to the light emitting surface with respect to the mounting position, the DB paste covering the desired light emitting direction side of the LED chip can be reduced.

The electrode includes a coating region and an auxiliary region formed on the light emitting surface side with respect to the coating region.
The two regions are connected to each other by a connecting portion formed narrow. As described above, the application area is an area where the DB paste is applied, and the auxiliary area is an area for securely connecting the LED chip to the electrode. In addition, since the connecting portion is formed to be narrow, it is possible to suppress the DB paste from spreading from the application region to the auxiliary region in a large amount. Therefore, LE
It is possible to reduce the amount of DB paste covering the desired light emitting direction side of the D chip.

Further, since the center of the application area is shifted from the center of the substrate in the direction opposite to the light emitting surface, if the LED chip is mounted on the center of the substrate after the DB paste is applied to the application area, the desired emission direction side can be obtained. Can be reduced. That is, if the shape of the electrode and the application position of the DB paste are changed, the conventional manufacturing method can be used.
A side-emitting semiconductor light emitting device can be manufactured.

[0010]

According to the present invention, light output in a desired light emitting direction is not blocked by the DB paste.
The luminous efficiency of light output from the LED chip can be increased.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a side-emitting semiconductor light emitting device (hereinafter simply referred to as "light emitting device") 10 of this embodiment.
Includes an insulating substrate (hereinafter simply referred to as “substrate”) 12 formed of, for example, glass epoxy. Substrate 1
On the reflector 2, a reflector (case) 14 made of a resin having a light-transmitting property and a reflective property is provided. Further, a space between the substrate 12 and the case 14 is filled with a translucent resin 16 such as an epoxy resin. That is, L
The ED chip 20 is sealed.

A lead (electrode) 18a is provided on the substrate 12.
As shown in FIG. 2A, which is a cross-sectional view taken along the line IIA-IIA of FIG. 1, a semiconductor light emitting element (LED chip) 20 is formed on the electrode 18a by a D like silver paste.
Die bonding is performed with B paste 24. Also,
As can be seen from FIG. 2B, which is a cross-sectional view taken along the line IIB-IIB in FIG. 1, the electrode 18b and the LED chip 20 are electrically connected by a bonding wire 22 such as a gold wire. Specifically, the bonding wire 22 is wire-bonded substantially parallel to the width direction A of the light emitting device 10. The electrode 18a is also formed continuously from the front surface to the rear surface of the substrate 14 through a through hole 12a provided on the side surface of the substrate 12, and can be directly mounted on a printed circuit board (not shown) to be electrically connected. It has become. Although not shown, the electrode 18b is similarly configured.

In FIGS. 1 and 2, the electrodes 18a and 18b are shown as having a certain thickness, but are actually formed in a thin film shape. In FIG. 2, the DB paste 24 is hatched for easy understanding of the DB paste 24, but the cross section is not shown. Further, as shown in FIG. 1, the electrode 18a is left so that the front surface side of the substrate 12 covers the through hole 12a, and when the translucent resin 16 is molded, The resin 16 is prevented from flowing. Although not shown, the electrode 18b side is similarly configured.

In this light emitting device 10, a desired light emitting direction P
The light output to is output through the light emitting surface 16 a formed of the translucent resin 16. To be precise, light is also output from the surface 16b formed of the translucent resin 16 and a surface parallel to the surface 16b and continuous with the surface 16a.

As shown in FIG. 3, the LED chip 20
It includes a p-type electrode (bonding pad) 20a connected to the bonding wire 22. Further, it includes an n-type electrode 20e connected to the electrode 18a. This n-type electrode 20e is also formed to a thin film thickness, similarly to the electrodes 18a and 18b. The LED chip 20 also includes a p-layer 20b, a light-emitting layer 20c, and an n-layer 20d, and the n-layer 20d, the light-emitting layer 20c, and the p-layer 20b are sequentially stacked on the n-type electrode 20e. The p-layer 20b and the n-layer 20d are each formed of a transparent semiconductor GaAs. Also, the n-type electrode 2
0e is formed of a reflective copper thin film or the like. Therefore, the light emitted from the light emitting layer 20c is output to the outside of the LED chip 20 via the p layer 20b and the n layer 20d. The light emitted below the light emitting layer 20c is n
Reflected on the surface of the mold electrode 20e, and
It is output to the outside of the ED chip 20.

Therefore, when the LED chip 20 is die-bonded to the electrode 18a with the DB paste 24, the n-layer 20d and the n-type electrode 20 are bonded with the DB paste 24.
e (the base 20f) is covered, and all the light output through the n-layer 20d is blocked by the DB paste 24. In order to avoid this, in this embodiment, FIGS.
As shown in (D), the LED chip 20 is die-bonded to maximize the light in the light emitting direction P.

That is, as shown in FIG. 4A, the LED chip 20 of this embodiment is shifted toward the light emitting surface 16a (desired light emitting direction P) with respect to the DB paste 24 so that the electrode 18 is shifted.
a is die-bonded. Therefore, when the LED chip 20 is viewed from the light emitting surface 16a side, the portion covered by the DB paste 24 on the light emitting direction P side of the LED chip 20 is reduced as shown in FIG. 4B. Further, when the LED chip 20 is viewed from the side parallel to the surface 16b and continuous with the light emitting surface 16a, as shown in FIG. It can be seen that the amount of the DB paste 24 continuously decreases. Further, the LED chip 20
When viewed from the side facing the light emitting surface 16a, FIG.
As shown in FIG. 3, in the direction opposite to the light emitting direction P of the LED chip 20, the amount of the DB paste 24 increases because the distance is close to the center of the application position of the DB paste 24, and the base of the LED chip 20 as shown in FIG. It can be seen that the platform 20f is covered. 4 (A) to 4 (D), the DB paste 24 is hatched for easy understanding,
Not a cross section.

As described above, the DB paste 24
In order to mount the ED chip 20 shifted to the light emitting surface 16a side, for example, the electrode 1 as shown in FIG.
8a may be formed. That is, the electrode 18a includes the application region 26a for applying the DB paste 24 and the auxiliary region 26b. The application area 26a has a substantially circular shape, and has a center Y shifted from the center X of the substrate 12 in the opposite direction to the light emitting surface 16a. The auxiliary region 26b is a vertically long rectangle, and is formed on the light emitting direction P (light emitting surface 16a) side with respect to the application region 26a. Further, the application region 26a and the auxiliary region 26b are connected to each other by a connecting portion 26c formed narrow.

The DB paste 24 is applied from the center Y of the application area 26a and spreads in a substantially circular shape. And FIG.
As shown in (B), the LED chip 20 is mounted at the center X of the substrate 12. 5 (A) and FIG.
In (B), in order to explain the electrode 18a easily,
The B paste 24 is omitted. Thus, the electrode 18
By forming a, the application position of the DB paste 24 is uniquely determined, and the LED chip 20 can be mounted on the DB paste 24 so as to be shifted toward the light emitting surface 16a.

Therefore, the light emitting surface 16 of the LED chip 20
The surface on the a side is not covered with the DB paste 24. That is, the light output in the light emitting direction P is not blocked by the DB paste 24.

By providing the auxiliary region 26b, the LED chip 20 can be reliably connected to the electrode 18a.

The size of the application area 26a is determined by the application amount and the viscosity of the DB paste 24. When the size of the application area 26a is determined, LE is applied.
The amount of shift in the direction opposite to the light emitting surface 16a is determined based on the mounting position of the D chip 20 (the center X of the upper surface of the substrate 12). In addition, since the application region 26a and the auxiliary region 26b are connected (connected) by the connecting portion 26c formed to be narrow, it is possible to suppress the DB paste 24 from spreading to the auxiliary region 26b in a large amount. That is, the DB paste 24 on the light emitting surface 16a side can be reduced. Further, the shape of the electrode 18a is not limited to the shape as shown in FIG. 5, but may be any shape as long as at least the application position of the DB paste 24 can be uniquely determined. Furthermore, electrode 1
If the light emitting device 8a is formed as shown in FIG. 5A and the application position of the DB paste 24 is changed, the light emitting device 10 of this embodiment can be manufactured using a conventional manufacturing device.

For example, when manufacturing (forming) such a light emitting device 10, the substrate 1 as shown in FIG.
The continuous substrate 30 and the case 14 in which a plurality of 2 are continuously formed.
And a continuous case 32 in which a plurality of are continuously formed.

Although not shown, the continuous substrate 30 has the number of light emitting devices 10 to be formed (1000 in this embodiment).
Electrodes 18a and 18b are formed continuously, and LED chips 20 corresponding to the number of light emitting devices 10 to be formed are bonded.

When attention is paid to one light emitting device 10, the electrodes 18a and 18b are formed in a shape as shown in FIG.
After being applied from the center Y of a, the LED chip 20 is mounted substantially at the center X of the substrate 12. Therefore, LE
The D chip 20 is die-bonded to the electrode 18a.
Subsequently, the LED chip 20 and the electrode 18b are electrically connected by the bonding wire 22. FIG.
In FIGS. 7A and 7B and FIGS. 7A to 7D, for simplicity, the electrode on which a plurality of electrodes 18a and 18b are continuously formed and the DB paste 24 are omitted.

The continuous substrate 30 to which the plurality of LED chips 20 are bonded and the continuous case 32 are bonded as shown in FIG. VIIA-VIIA in FIG. 6 (B)
As can be seen from FIG. 7A, which is a cross-sectional view, the cross section of the member 32a included in the continuous case 32 is formed in a T-shape.
A plurality of members 32a are formed in the horizontal direction at predetermined intervals. The member 32a is also continuous in a direction perpendicular to the plane of FIG. That is, the member 32a has a T-shaped cross section and is formed in a rod shape.

As can be seen from FIG. 6A, the ends of the members 32a are connected to each other to form one continuous case 32. The continuous case 32 is adhered to the continuous substrate 30 at a portion corresponding to the bottom of the T-shaped vertical bar.

As can be seen from FIG. 7A, the openings 34 formed by bonding the continuous substrate 30 and the continuous case 32 face each other. This opposing part 3
Light-transmissive resin 16 is injected into 8.

More specifically, a flat mold 36 as shown in FIG. 7B is pressed against the upper surface of the continuous case 32. Subsequently, as shown in FIG. 7C, the translucent resin 16 is injected into the facing portion 38.
When the injection of the translucent resin 16 is completed, the translucent resin 16 is cured, and the mold 36 is removed from the continuous case 32. Then, dicing is performed by a dicer (not shown) at a position indicated by a dotted line in FIG. Further, as can be seen from FIG. 7D corresponding to the sectional view taken along the line VIID-VIID in FIG.
Dicing is also performed for each width of the (light emitting device 10). Therefore, a plurality of light emitting devices 10 as shown in FIG. 1 are formed.

As described above, since the dicing is performed by the dicer, the light emitting surface 16a of the light emitting device 10 is formed by the dicing surface. That is, fine unevenness is formed on the light emitting surface 16a due to the roughness of the dicer blade, so that light output from the LED chip 20 is scattered on the light emitting surface 16a.
Therefore, the light emitting area can be enlarged as compared with the case where the light emitting surface 16a of the LED chip 20 is mirror-finished. In addition, the surface 16b and the surface parallel to the surface 16b and continuous with the light emitting surface 16a are similarly formed as dicing surfaces.

According to this embodiment, since the mounting position of the LED chip is shifted to the light emitting surface side with respect to the application position of the DB paste, the surface on the light emitting surface side of the LED chip is not covered with the DB paste. In other words, the light output in the desired light emitting direction is not blocked by the DB paste,
Luminous efficiency can be increased. That is, luminous efficiency can be improved.

In this embodiment, after the continuous case is bonded to the continuous substrate, the translucent resin is injected as it is. However, the continuous case is irradiated with ultraviolet rays for a predetermined time (for example, 3 minutes). If the translucent resin is injected after cleaning the surface of the continuous case, the adhesive strength between the translucent resin and the continuous case can be increased. That is, it is possible to prevent the case from coming off the substrate due to physical impact such as dicing.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing one embodiment of the present invention;

FIG. 2 is a sectional view of the light emitting device shown in FIG.

FIG. 3 is an illustrative view showing the LED chip shown in FIG. 2;

4A is an illustrative view of the LED chip and the DB paste bonded to the electrodes shown in FIG. 1 from above, and FIG. 4B is an illustrative view showing the LED bonded to the electrodes shown in FIG. FIG. 2 is an illustrative view of the chip and the DB paste as viewed from the light emitting surface side, FIG. 2C is an illustrative view of the LED chip and the DB paste bonded to the electrode shown in FIG. LED chip and DB bonded to electrode shown in FIG. 1 embodiment
FIG. 3 is an illustrative view of the paste as viewed from a side opposite to a light emitting surface.

5A is an illustrative view showing one example of an electrode for mounting an LED chip shifted from a DB paste application position to a light emitting surface side, and FIG. 5B is an illustrative view showing one example of an electrode shown in FIG. 5A; FIG. 4 is an illustrative view showing a state where an LED chip is mounted;

FIG. 6A is an illustrative view showing a continuous substrate and a continuous case when the light emitting device shown in FIG. 1 is manufactured;
FIG. 7B is an illustrative view showing a state where the continuous substrate and the continuous case shown in FIG.

7A is a cross-sectional view of the continuous substrate and the case shown in FIG. 6B, and FIG. 7B is a diagram illustrating a continuous case bonded to the continuous substrate of FIG. 7A and pressed against the continuous case. It is sectional drawing which shows a metal mold | die, (C) is sectional drawing which shows the state which pressed the metal mold | die against the continuous case, and injected | transduced the translucent resin, and (D) is a dicing process for every width | variety of a light emitting device. FIG.

8A is an illustrative view showing one example of a conventional side emission semiconductor light emitting device, and FIG. 8B is a sectional view of the side emission semiconductor light emitting device shown in FIG. 8A.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Light emitting device 12 ... Substrate 14 ... Case 16 ... Translucent resin 20 ... LED chip 22 ... Bonding wire 24 ... DB paste 26a ... Application area 30 ... Continuous substrate 32 ... Continuous case 34 ... Opening 36 ... Die 38 ... Opposite part

Claims (4)

[Claims] An LE having a transparent base and a light-emitting layer thereon
A side-emitting semiconductor light-emitting device in which a D chip is bonded to an electrode on a substrate, wherein a mounting position of the LED chip is shifted to a light-emitting surface side with respect to a bonding paste application position. 2. The side-emitting semiconductor light emitting device according to claim 1, wherein said electrode includes a coating region having a center shifted in a direction opposite to said light emitting surface with respect to said mounting position. 3. The electrode according to claim 1, wherein the electrode includes an application region, an auxiliary region formed on the light emitting surface side with respect to the application region, and a narrow connecting portion connecting the application region and the auxiliary region. The side-emitting semiconductor light-emitting device according to claim 2, comprising: 4. A side-emitting semiconductor light emitting device according to claim 2, wherein said center of said coating region is shifted from said center of said substrate in said opposite direction.