JPH0541561A - Semiconductor light emitting device - Google Patents

Abstract

PURPOSE:To obtain a semiconductor light emitting device which can acquire information from the desired distance or range, while cutting unnecessary information. CONSTITUTION:A plurality of light emitting diodes LD 21, 22, 23 are arranged in the form of arrays on a substrate 1. In some cases, a light emitting region is further formed at the center LD21 of three arrays, or a light emitting region is further formed and its area is wide, or a wide light emitting region is formed. In any case, the center laser chip emits a laser beam intensified by two to three times that of the light emitting diodes LD22, and LD23 on both sides of the center chip.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device having a plurality of laser diodes.

[0002]

2. Description of the Related Art In a conventional semiconductor light emitting device in which a plurality of laser diodes (hereinafter abbreviated as LD) are formed on a substrate in an array type, characteristics such as a light output and a radiation pattern of each LD are determined. Under the same driving condition, it has been required to obtain the same and accurate. Therefore, a semiconductor light emitting device that meets the requirements has been designed and manufactured.

FIG. 4 (a) shows an example of how the semiconductor light emitting device is used. In FIG. 4 (b), three LDs 2 ₁ , 2 ₂ , 2 ₃ are arrayed on a substrate 1. A cross section of the device formed in FIG. These LD2 ₁ , 2 ₂ , 2
As described above, the characteristics of the _three LDs are designed to be equal under the same driving condition, so that the LDs have the same radiation pattern and the same light output.

[0004]

FIG. 4A is a diagram showing a radiation pattern when the above-described light emitting device of FIG. 4B is used in a laser radar for automobiles. In the figure (a), P ₁ , P ₂ and P ₃ are LD ₁ , LD ₂ and L in the forward direction.
The range of the optical power of D ₃ is shown. As shown,
The light power ranges P ₂ and P ₃ of the LDs _{2 2} and LD _{2 3} located at both ends of the three LDs arranged in an array form are reflected light information of a region outside the one lane and the center line of the road (in the figure). , The information from the shaded area) is unnecessary, so it is necessary to remove it by some processing.

Further, since the signal in the area shown by the dot in the figure cannot be obtained, when another vehicle overtakes,
There is a problem that this area becomes a blind spot of the laser radar device.

It is an object of the present invention to provide a semiconductor light emitting device that solves these problems.

[0007]

According to the present invention, in a semiconductor light emitting device having a plurality of laser diodes formed in an array on a substrate, at least one laser diode among the plurality of laser diodes is two. The above-mentioned light emitting portion is laminated, or at least one laser diode among a plurality of laser diodes is formed so that its light emitting area is different from other light emitting areas. In addition to the above characteristics, the optical waveguides of the plurality of laser diodes may be formed so as not to be parallel to each other.

[0008]

According to the present invention, a certain LD among a plurality of LDs arranged in an array is formed by laminating several light emitting portions, or by increasing the light emitting area thereof, the light output of the LD is increased. Can be made larger than other LDs.

[0009]

1 is a view showing an embodiment of a semiconductor light emitting device of the present invention. Here, a cross section of an apparatus in which three LDs are arranged in an array on the substrate 1 is shown.

[0010] FIG. (A), the three of LD2 ₁ central array consisting of LD, three light emitting portion 20A~2
0C is formed by stacking, and the left and right LDs _{2 2} and 2 ₃ are composed of only a single light emitting part.
Is a cross-sectional area of the light emitting portion 20A~20C of each layer constituting the LD2 ₁ central array of three LD, left and right L
It is wider than the light emitting portions of D2 ₂ and 2 ₃ . The same figure (c) shows LD2 _{1 at} the center of the array of three LDs.
In regard to the above, the area of the central light emitting portion is made larger than that of the left and right without forming the light emitting portions in layers.

With any of the structures, the sectional view of the light emitting portion of the central LD ₁ can be effectively made wider than the LDs 2 ₂ and 2 ₃ on both the left and right sides, so that a laser output of 2-3 times stronger than that of the central LD ₁ is obtained. Is emitted. Further, since the area of the light emitting portion of the central LD ₁ is increased, the left and right LD ₂ , LD ₃
The radiation pattern of LD _{1 at} the center is narrower than that of.

FIG. 2 is a diagram showing a radiation pattern when the above-mentioned light emitting device is used in a laser radar for automobiles. LD _{1 in} the center of the structure in which the light emitting part is laminated or widened
Optical power P ₄ from the light emitting portion of the right and left LD _2, LD ₃
Is greater than the optical powers P ₅ and P _{6 of} the traveling vehicle (for example, a truck) compared to the left and right in the traveling direction, information in front of the traveling direction from a long distance (reflected light information of laser light). ) Can be obtained. The optical powers P ₅ and P ₆ of the LDs _{2 2} and 2 ₃ located at both ends of the central LD ₁ are adjusted to appropriate powers so that the light beam does not reach the outside of the road or the opposite lane. It becomes possible to cut off unnecessary signals. Further, the optical power P ₄ of the central LD ₁ is strong, and the radiation pattern is narrow as described above. It is also possible to have a broad radiation pattern.

FIG. 3 is a diagram showing another embodiment of the semiconductor light emitting device of the present invention. As you can see from the figure, 3 L's
The optical waveguides of the LDs _{2 2} and 2 ₃ located at both ends of the array made of D were previously dry-etched in an ultrahigh vacuum.
It is formed obliquely with respect LD2 ₁ of the center. In this structure, to the laser light from LD2 _1, LD2 _{2, 2 3}
The laser light from is emitted obliquely. As a result, the reflection signal can be obtained from the area indicated by the dot in FIG. 4, that is, the area where the conventional apparatus cannot irradiate the laser beam and thus the reflection signal cannot be obtained.

In the embodiment described above, 3
Although the case of an array of LDs has been described, the present invention is not limited to this. Further, although the LD has a three-layer structure, it is not limited to this, and the same effect as that of the present embodiment can be obtained with a two-layer structure or a multi-layer structure of four or more layers.

[0015]

According to the present invention, LDs arranged in an array form
Since the characteristics such as the light output and the radiation pattern can be individually changed, by using this LD as a light source for a laser radar, a desired distance can be obtained in a far range in the front and a wide range in the side. Only information can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a semiconductor light emitting device according to an embodiment of the invention.

FIG. 2 is a diagram showing a light emission pattern when the semiconductor light emitting device of the present invention is used.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing a conventional semiconductor light emitting device.

[Explanation of symbols]

1 ... Substrate 2 ₁ , 2 ₂ , 2 ₃ ... LD (laser diode) 20A, 20B, 20C ... Light emitting part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Matsui 1 1126, Nomachi, Hamamatsu City, Shizuoka Prefecture 1126 Hamamatsu Photonics Co., Ltd. (72) Hirofumi Miyajima 1126, 1126 Ichinocho, Hamamatsu City, Shizuoka Prefecture Hamamatsu Photonics Within the corporation

Claims (3)

[Claims] 1. A semiconductor light emitting device having a plurality of laser diodes formed in an array on a substrate, wherein at least one laser diode among the plurality of laser diodes is formed by stacking a plurality of light emitting portions. A semiconductor light-emitting device characterized by being provided. 2. A semiconductor light emitting device having a plurality of laser diodes formed in an array on a substrate, wherein at least one laser diode among the plurality of laser diodes has another light emitting portion whose cross-sectional area is different. A semiconductor light emitting device characterized in that it is formed larger than a laser diode. 3. The semiconductor light emitting device according to claim 1, wherein the optical waveguides forming the light emitting portions of the plurality of laser diodes are formed so as not to be parallel to each other.