JP3312869B2 - Light emitting diode element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode device.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional so-called discrete type light emitting diode 20. A light emitting diode chip (light emitting diode) having a light emitting junction (PN junction) as shown in FIG. Element 21 is joined, the tip of the other lead 23 and the electrode 21a provided on the surface of the P layer are connected by a bonding wire 24, and the light emitting diode chip 21 and each lead 2 are connected.
The tip portions 2 and 23 are sealed with a transparent resin 25 such as an epoxy resin in a shell shape.

The light emitting diode 20 emits monochromatic light. For example, as shown in FIG. 8, when a plurality of light emitting diodes are mounted on a circuit board 26 and energized, the light emitting diode 20 is used as an indicator or the like with a specific light emitting color. . As described above, the light emitting diode is conventionally used exclusively as a display element. However, in recent years, a light emitting diode having a high light emission luminance has been provided. Utilization of is being studied. In other words, a planar light source is formed by arranging a plurality of high-brightness light emitting diodes side by side. Since the light emitting diodes have a longer life than fluorescent lamps or incandescent lamps, they are almost semi-permanently replaced or maintained. This is unnecessary, and there is an advantage that a lighting device or a traffic light at a high place can be used instead of a fluorescent lamp or an incandescent lamp. In addition, among light emitting diodes having high energy efficiency, some light emitting diodes that exceed the energy efficiency of light bulbs are provided, and expectations for energy saving are increasing.

In order to increase the amount of light emission by flowing a large current, the size of the light emitting diode element is increased because the current capacity of the light emitting diode element is proportional to the area of the light emitting junction (PN junction). That is, if the cutting size when cutting from the wafer is increased, the current capacity of the light emitting diode element is increased, and the light emission amount can be increased.

[0005]

However, even if the light emitting diode element is enlarged, current concentration occurs in the element depending on the wiring pattern of the circuit on which the element is mounted, and the light emission luminance may be biased, or the light emitting luminance may be partially reduced. A problem occurs in which the current is saturated and the element generates heat, leading to a decrease in luminous efficiency. For example, as shown in FIG.
If 0 is a size having an area four times as large as a normal size (see FIG. 7), the electrode (bonding pad) 31 formed on the non-mounting surface has a size of 4 in consideration of current capacity and current dispersion in the element. It is divided into pieces.

On the other hand, with the increase in the element size, as shown in FIG. 6, the light emitting diode element 30 is provided not on the tip of the lead 22 but on a wiring portion (wiring pattern) 32 made of metal foil conductor or metal plate etching of the circuit board. Is placed and connected to it. As shown in FIG. 10, a large amount of current flows between the wiring portion 32 and the electrode 31 nearer to the routing pattern 33 of the wiring portion 32 (the current density increases). (See the dotted arrow in FIG. 10). Therefore, as the light emitting diode element, the brightness near the wiring pattern 33 increases, and the brightness far from the wiring pattern 33 decreases. Further, when the supplied current is near the limit of the element size, the current is saturated in the portion where the current density is high, the amount of heat generation increases, and the luminous efficiency at a high temperature decreases as is well known.

SUMMARY OF THE INVENTION An object of the present invention is to provide a light emitting diode device which increases a light emission amount by flowing a large current and suppresses a decrease in light emission efficiency due to partial current saturation and heat generation. What you want to do.

[0008]

According to a first aspect of the present invention, there is provided a light emitting device having a light emitting junction and a mounting surface and a non-mounting surface.
A light emitting diode element having a respective electrode on the mounting surface, to counter the electrodes of the mounting surface and the non-mounting surface, respectively
Divided into a plurality in so that arrangement, the collector of the non-mounting surface
Exposing at least the light emitting junction in the area where no pole is formed
And an exposed groove on the mounting surface.
A diffusion portion having low resistance is formed at a position opposed to the groove, so that the current flowing through the electrode can be distributed substantially uniformly in the light emitting diode element, and even when the element size is increased, a partial current is generated. A light-emitting diode element that can suppress the decrease in luminous efficiency due to current saturation and heat generation, increase the amount of light emission by increasing the current capacity , and improve the luminous efficiency by applying a large amount of current to the exposed part of the light-emitting junction. Can be provided.

The invention of claim 2 achieves the above object.
In order to achieve this, light-emitting
A light emitting diode element comprising:
Multiple electrodes are arranged so that each electrode on the non-mounting surface faces each other
Divided it by the includes a wiring portion connected to each electrode of the mounting surface, a portion which is branched to the connecting portion between the electrodes of the wiring portion, the resistance value of each branch portion becomes substantially equal to the width It is characterized in that it is formed in dimensions, and the current flowing through the electrodes is
It can be distributed almost uniformly within the iodine element,
Even if the size is increased, the current is averaged and partially
To reduce the luminous efficiency due to excessive current saturation and heat generation.
Light-emitting diode element that can increase the amount of light emission by increasing the amount
Child can provide. The invention of claim 3 achieves the above object.
In order to have a light emitting junction,
A light-emitting diode element with electrodes
And the electrodes on the non-mounting surface face each other.
Divided into a plurality and the electrodes on the non-mounting surface are formed
Exposed grooves that expose at least the light-emitting junction
And divide it into multiple blocks, and
And the current density around the block is approximately at the center of the block.
Characterized in that a recess for increasing the the electrode
Current flowing through the light-emitting diode
Even if the element size is increased.
Suppress decrease in luminous efficiency due to partial current saturation and heat generation
It is possible to increase the amount of light emission by increasing the current capacity.
When a large amount of current is applied to the exposed part of the light emitting junction,
A light emitting diode element capable of improving the efficiency can be provided.

According to a fourth aspect of the present invention, in the first aspect of the present invention, a portion of the non-mounting surface where the electrode is not formed.
Provide at least an exposure groove for exposing the light emitting junction
While dividing into blocks,
To increase the current density around the block almost in the center of the lock
Recesses are formed to expose the light-emitting junction.
A large amount of current can be passed through the site , and the luminous efficiency can be improved. According to a fifth aspect of the present invention, in the first or second or third aspect of the present invention, a groove is provided on a mounting surface .
Further, the current can be averaged.

[0011]

(Embodiment 1) An exploded perspective view of Embodiment 1 of the present invention is shown in FIG. N by semiconductor process
A wafer having a P-type layer formed on a mold substrate is cut into an appropriate size, and an electrode 2 made of a metal such as Au is formed on the surface (non-mounting surface) of the P layer 1a and the back surface (mounting surface) of the N layer 1b. Are provided in plurality (four in this embodiment) to form the light emitting diode element 1. However, each electrode 2 on the front and back surfaces is a P layer 1a.
It is desirable to arrange them so as to face each other with the N layer 1b interposed therebetween.

An electrode (not shown) on the back surface is connected to the connection portion 11 of the wiring portion 10 formed on the circuit board by die bonding, and the electrode 2 on the front surface is connected to a wiring pattern (not shown) by wire bonding. Thus, the light emitting diode element 1 is assembled. here,
In the conventional light emitting diode element 21 shown in FIG. 7, the vertical and horizontal dimensions of the front and back surfaces are set to about 0.2 to 0.3 [mm].
A current of about 20 [mA] to 10-20 [mc
d) is obtained. If the viewing angle is reduced by using the sealing resin 25 for the lens as shown in FIG.
A degree of brightness can be obtained. In this embodiment,
In order to quadruple the area of the front surface (and the back surface) of the conventional example, the wafer is cut at twice the pitch of the conventional example.

In this embodiment, since the electrodes 2 provided on the front surface and the rear surface are divided into a plurality of parts, the distribution of the current flowing in the inside is substantially reduced despite the increase in the element area as compared with the conventional example. It can be uniform. That is, by increasing the area of the light emitting diode element 1, the current capacity can be increased and the light emission amount can be increased, and the distribution of the current flowing inside the light emitting diode element 1 is substantially uniform. As a result, the light-emitting diode element 1 with high luminous efficiency can be realized without partial current saturation, and the heat generated by energization is generated substantially uniformly, without bias, and the occurrence of uneven brightness can be prevented. It should be noted that, compared to mounting a large number of small light emitting diode elements 21 as in the conventional example to increase the amount of light, a light emitting diode element having a large size, allowing a large current to flow, and emitting a large amount of light as in the present embodiment. The use of 1 has the advantage that the number of light emitting diode elements 1 required to obtain a desired light amount can be reduced, and the number of steps required for mounting can be reduced.

In this embodiment, a portion 12 of the wiring portion 10 formed on the circuit board is branched into each connection portion 11.
Are formed in a width dimension such that the resistance value of each branch portion 12 is substantially the same. Therefore, the current flowing through the wiring portion 10 and the current flowing through the light emitting diode element 1 can be averaged. As shown in FIG. 2, if grooves 3 for dividing the electrodes into blocks are provided in the N layer 1b from the back surface (mounting surface) side, the current flowing in the light emitting diode element 1 can be separated and averaged. It can be carried out. The groove 3 can be easily formed by processing the back surface of the light emitting diode element 1 by etching, dicing blade machining, or the like.

Embodiment 2 FIG. 3 shows a side view of Embodiment 2 of the present invention. In this embodiment, the light emitting diode element 1
The surface (non-mounting surface) is provided with an exposure groove 4 for exposing the light emitting junction, and a diffusion portion (P ⁺ layer) 5 having low resistance is formed near the periphery on the back surface (mounting surface) side. In addition, the configuration other than the P layer 1a on the back side and the N layer 1b on the front side is common to the first embodiment.

Conventionally, in order to improve the luminous efficiency, as shown in FIG. 4, an exposed groove 4 'reaching the light emitting junction from the surface of the light emitting diode element 1' is provided so that the light emitting junction is exposed from the exposed groove 4 '. (Japanese Unexamined Patent Publication No.
0-105286). Thus, in the present embodiment, the current distribution can be made substantially uniform by flowing a current from each electrode 2 for each block divided by the exposure groove 4, and the vicinity of the periphery on the back surface (mounting surface) side (Exposed groove 4
By lowering the resistance value at the diffusion portion 5 provided at (a position facing), the current density near the exposed groove 4 is increased, the current amount near the light emitting junction is increased, and the luminous efficiency can be increased. The diffusion portion 5 may be formed by diffusing a high-concentration P ⁺ material from the back surface side of the light emitting diode element 1.

As shown in FIG. 5, if the concave portion 6 is formed at an approximate center of the back surface (mounting surface) of each block divided by the exposure groove 4 by an appropriate method such as etching, the peripheral portion of each block is similarly formed. By increasing the current density (in the vicinity of the exposed groove 4), the amount of current near the light emitting junction can be increased, and the luminous efficiency can be increased.

[0018]

Effect of the Invention of Claim 1 invention, the real has an emission junction
A light emitting diode element having a respective electrode to Somen and non-mounting surface, it the electrodes of the mounting surface and the non-mounting surface
Divided into multiple parts so that they face each other, and
At least in a portion where the electrode is not formed.
Provide an exposed groove to expose the
A diffusion portion having low resistance at a position facing the exposed groove.
As a result, the current flowing through the electrodes can be distributed almost uniformly in the light emitting diode element, and even when the element size is increased, the reduction in luminous efficiency due to partial current saturation and heat generation is suppressed, and the current capacity is increased. It is possible to increase the amount of luminescence , and moreover,
The present invention has the effect of providing a light emitting diode element capable of improving the luminous efficiency by passing the current .

According to a second aspect of the present invention, there is provided a light emitting device having a light emitting junction.
Light-emitting diode element having electrodes on both the surface and the non-mounting surface
And the electrodes on the mounting surface and the non-mounting surface are respectively
It is divided into a plurality of parts so as to face each other, and has a wiring part connected to each electrode on the mounting surface, and a part branched to a connection part of each wiring part with each electrode is a resistance of each branch part. since the value is a width dimension of the substantially the same, the flow through the electrode
Current can be distributed almost uniformly in the light emitting diode element.
Even when the element size is increased, the current is flattened.
Reduction of luminous efficiency due to partial current saturation and heat generation
To increase the amount of light emission by increasing current capacity
There is an effect that a photodiode element can be provided . The invention according to claim 3 has a light emitting junction and has a light emitting junction on a mounting surface and a non-mounting surface.
Light-emitting diode elements with electrodes
Arrange the electrodes on the surface and the non-mounting surface so that they face each other.
And the electrodes are formed on the non-mounting surface.
Exposed groove that exposes at least the light emitting junction in the part that is not
To divide into multiple blocks,
And the current around the block is located approximately at the center of the block.
Since a recess for increasing the density through the electrode
Distribute the flowing current almost uniformly in the light emitting diode element
Even if the element size is increased.
To reduce the luminous efficiency due to excessive current saturation and heat generation.
The amount of light emission can be increased by increasing the amount,
A large amount of current is applied to the exposed part of the junction to improve luminous efficiency.
There is an effect that a light emitting diode element which can be provided can be provided .

According to a fourth aspect of the present invention, the non-mounting surface is
Exposing at least the light emitting junction to the area where no electrode is formed
It is divided into multiple blocks by providing an exposed groove
In the mounting surface, a block is provided substantially at the center of the block.
Since a concave part was formed to increase the current density in the peripheral part ,
There is an effect that a large amount of current can flow through the exposed portion of the light emitting junction, thereby improving the luminous efficiency. Claim 5
Is characterized in that a groove is provided on the surface to be mounted.
This has the effect that the current can be averaged .

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a first embodiment.

FIG. 2 is a perspective view showing another configuration of the above.

FIG. 3 is a side view showing the second embodiment.

FIG. 4 is an explanatory diagram for explaining the above.

FIG. 5 is a side view showing another configuration of the above.

FIG. 6 is a side view showing a conventional discrete light emitting diode.

FIG. 7 is a perspective view showing the light emitting diode element of the above.

FIG. 8 is a perspective view showing an indicator using the light emitting diode of the above.

FIG. 9 is a perspective view showing another conventional example.

FIG. 10 is an explanatory diagram for explaining the above function.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting diode element 2 Electrode 10 Wiring part 11 Connection part

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobuyuki Asahi 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. Inventor Yasushi Akiba 1048 Kadoma Kadoma, Kadoma City, Osaka Pref. (72) Inventor Koji Tanaka 1048 Kadoma Kadoma, Kadoma, Osaka Pref. No. 1048 Matsushita Electric Works Co., Ltd. references Patent flat 1-280368 (JP, a) (58 ) investigated the field (Int.Cl. ^7, DB name) H01L 33/00 JICST off Yl (JOIS)

Claims (5)

(57) [Claims] 1. A light emitting diode element having a respective electrode on the mounted surface and the non-mounting surface has a light-emitting junction, the mounted
Arrange the electrodes on the surface and the non-mounting surface so that they face each other.
And the electrodes are formed on the non-mounting surface.
Exposed groove that exposes at least the light emitting junction in the part that is not
And facing the exposed groove on the mounting surface.
A light-emitting diode element, wherein a diffusion portion having low resistance is formed at a position where the light-emitting diode is formed . 2. A light emitting junction having a light emitting junction on a surface to be mounted and a non-mounting surface.
Light-emitting diode elements with electrodes
Arrange the electrodes on the surface and the non-mounting surface so that they face each other.
It is divided plurality in location, includes a wiring portion connected to each electrode of the mounting surface, a portion which is branched to the connecting portion between the electrodes of the wiring portion, substantially the same resistance value of each branch portion to that light-emitting diodes device characterized in that it is formed to the width of the. 3. A light emitting junction having a light emitting junction on a surface to be mounted and a non-mounting surface.
Light-emitting diode elements with electrodes
Arrange the electrodes on the surface and the non-mounting surface so that they face each other.
And the electrodes are formed on the non-mounting surface.
Exposed groove that exposes at least the light emitting junction in the part that is not
To divide into multiple blocks,
And the current around the block is located approximately at the center of the block.
Emitting <br/> photodiode element you characterized in that a recess for increasing the density. 4. The method according to claim 1, wherein the electrode is formed on a non-mounting surface.
Exposed grooves that expose at least the light-emitting junction
And divide it into multiple blocks, and
And the current density around the block is approximately at the center of the block.
Wherein a recess for raising the height is formed.
1 Symbol mounting of the light emitting diode element. 5. A groove is provided on a mounting surface.
The light-emitting diode device according to claim 1 .