JP3351103B2 - Semiconductor light emitting device - Google Patents

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 such as a semiconductor laser and a light emitting diode, and more particularly to a high power and high efficiency semiconductor light emitting device.

[0002]

2. Description of the Related Art In recent years, there has been a demand for high-power semiconductor light emitting devices such as semiconductor lasers and LEDs. The operation of the light-emitting element at a high output causes an increase in operation current and an increase in heat generation during the operation, which greatly affects the life and reliability of the light-emitting element.

FIG. 14 shows a cross section of a conventional semiconductor light emitting device 101. A conventional semiconductor light emitting device 101 has a copper block 10 on a stem 102 in order to improve heat radiation characteristics.
The semiconductor laser chip 104 is die-bonded face down to the copper block 103. Copper block 1
A method of mounting a semiconductor laser chip 104 on a submount (not shown) made of diamond or the like having good heat conduction properties is provided on the submount 03.

The semiconductor laser chip 104 has a wire 1
The light emitted from the semiconductor chip 104 is connected to the lead wire 106 through the opening 05 and is emitted to the outside from the opening 107 of the cap 108 provided with the glass plate 106. The inside of the cap 108 is filled with a gas 109 made of air or an inert gas.

[0005] Further, a wavelength conversion element for converting the wavelength of light emitted from such a conventional light emitting element is known. JP-A-63-128914 discloses a blue laser light source and an optical information recording device using a semiconductor laser and a wavelength conversion element. Japanese Patent Application Laid-Open Nos. 1-237887 and 1-63731 disclose a semiconductor laser, a lens for condensing semiconductor laser light, a wavelength conversion element, and an inert medium for preventing deterioration of the wavelength conversion element. A semiconductor device is shown.

[0006]

However, in the above-described semiconductor light emitting device according to the prior art, the heat generated by the operation is mainly dissipated only from the contact portion between the semiconductor laser chip 104 and the copper block 103, so that the heat radiation efficiency is low. Therefore, particularly when the semiconductor light emitting device 101 is operated at a high output, the temperature of the semiconductor laser chip is extremely increased due to low heat radiation efficiency, and the semiconductor light emitting device 101 is significantly deteriorated.

In the above-described semiconductor device having the semiconductor light emitting element and the wavelength conversion element, the light emitted from the semiconductor chip has a wide emission angle. It was difficult to lead to. As a result, the external emission efficiency has deteriorated.
Although it is possible to collect light emitted from the semiconductor chip by using a plurality of lenses, the structure of the device becomes complicated, which leads to an increase in manufacturing cost or difficulty in manufacturing a small device. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a semiconductor light emitting device having high output, high reliability, and high efficiency with a simple structure. It is in.

[0009]

A semiconductor light emitting device according to the present invention comprises a semiconductor light emitting chip having a light emitting surface, a cap enclosing the semiconductor light emitting chip, and an insulating non-conductive material filled so as to leave a space inside the cap. and an active liquid, the calibration
The top is provided with a surface provided with a concave portion having an opening at the bottom,
The semiconductor light-emitting element provided in the mouth transmits light emitted therefrom.
And a transparent plate made of a material such as
The entire surface of the transparent plate is filled with the insulating inert liquid.
As a result, the above object is achieved.

[0010]

[0011] The transparent plate may be an optical lens.
Further, the semiconductor light emitting device further includes a microcapsule sealed in the cap, and means for preventing the microcapsule from blocking light emitted from a light emitting surface, wherein the space is formed in the microcapsule. It may be included.

[0012]

[0013]

Wavelength conversion of light from a semiconductor light emitting chip
It is preferable to have a light wavelength conversion element. Preferably, the insulating inert liquid is a fluorine-based inert liquid.
Further, it is preferable that the insulating inert liquid is a fluorine-based inert liquid containing no chlorine.

In addition, the volume of the space and the insulating inertness
Preferably, the ratio to the volume of the liquid is about 1: 9.

[0016]

An inert liquid having a high refractive index is used in a semiconductor light emitting device as an optical medium having high thermal conductivity and capable of being optically connected to a light emitting surface of a light emitting body or a light emitting surface of the device.

[0017] Thus, since the heat dissipation of the semiconductor light emitting chip is performed not only from the copper block but also through the inert liquid, the entire chip can be cooled.
It is possible to improve not only the temperature characteristics of the semiconductor light emitting element but also the reliability.

Since a space is provided in the container for enclosing the inert liquid, the volume expansion of the inert liquid due to a temperature change can be absorbed. Also, the spread of the emission angle of the laser light emitted from the semiconductor laser or the optical wavelength conversion element is suppressed,
It is possible to efficiently make the light enter the condenser lens or the light wavelength conversion element. Therefore, the aperture diameter NA of an optical lens such as a condenser lens can be reduced, and the size and cost of the laser light source device can be reduced.

[0019]

The present invention will be described below with reference to examples.

(Embodiment 1) FIG. 1 is a sectional view of a semiconductor light emitting device 1 according to a first embodiment of the present invention. The semiconductor light emitting device 1 has a stem 2, a copper block 3 provided on the stem 2, and a semiconductor laser chip 4 die-bonded to a part of the copper block 3. The stem 2 is provided with a lead wire 5 and is connected to the semiconductor light emitting chip 4 via a wire 6. Semiconductor light emitting device 1
Has a cap 7 provided so as to enclose the semiconductor laser chip 4 and the copper block 3. Cap 7
Is provided with an opening 8, and the opening 8 is provided with a glass plate 9.
Is attached. Light emitted from the semiconductor light emitting chip 4 passes through the glass plate 9 and is emitted to the outside of the semiconductor element 1. The glass plate 9 is made of a material that transmits light emitted from the semiconductor laser chip 4. Cap 7
Are welded to the stem 2. To leave a space 11 in the space formed by the stem 2 and the cap 7,
An insulating inert liquid 10 is enclosed.

The insulating inert liquid 10 is electrically insulating.
Liquid that does not react with the material of the semiconductor light emitting chip 4
You need to be a body. Further, an insulating inert liquid 10
Does not absorb light emitted from the semiconductor light emitting chip 4
It is necessary. Specifically, ether, alcohol
, Polychlorinated biphenyl (PCB), ethylene glycol
And a fluorine inert liquid are suitable. In particular, fluorine
1 × 10 inert liquid ¹⁴Has a specific resistance of Ωcm or more,
In addition, the present invention does not absorb light having a wavelength of 1 μm or less.
Suitable as an insulating inert liquid to be used.

FIG. 2 shows a comparison of the thermal conductivity between air and a fluorine-based inert liquid due to natural convection. The fluorinated inert liquid has a thermal conductivity that is about one order of magnitude higher than that of air and nitrogen gas, and this value is almost equal to that of water. Therefore, the heat generated by the semiconductor laser chip 4 is not only radiated from the connection surface between the copper block 3 and the semiconductor laser chip 4 but also radiated from the entire surface of the semiconductor laser chip 4 to the insulating inert liquid 10. . Further, since the insulating inert liquid 10 is inactive with respect to the surface of the semiconductor laser chip 4, it is possible to prevent the light emitting end face of the semiconductor laser chip 4 made of a semiconductor containing aluminum from being oxidized and deteriorated. As the fluorine-based insulating inert liquid, for example, fluorine-based hydrocarbons such as Freon and trade name Florinert are suitable. In this embodiment, IL270 manufactured by Tokuyama Soda Co., Ltd. is used as the fluorine-based inert liquid, but it is easily understood that another kind of fluorine-based inert liquid may be used.

FIG. 3 shows the temperature dependence of the density of the fluorine inert liquid IL270. Between 0 ° C. and 50 ° C. the density decreases by about 10%. Therefore, it is understood that the space 11 needs to be provided so that the insulating inert liquid sealed in the cap 7 and the stem 2 undergoes thermal expansion with a rise in temperature and the shape of the package is not deformed or damaged. The storage temperature range of a semiconductor laser is usually -20
Since the temperature during assembly and mounting is about 25 ° C. from about 80 ° C. to about 80 ° C., an insulating inert liquid is used so that the volume of the space 11 remains about 10% or more of the total space formed by the cap 4 and the stem 2. Preferably, 10 is enclosed.

A method for manufacturing the semiconductor light emitting device 1 will be described with reference to FIG. After the stem 2, the lead wire 5, the copper block 3, and the semiconductor laser chip 4 are connected to each other by a conventional method such as die bonding, the lead wire 5 and the semiconductor laser chip 4 are connected by wires 6. A cap 7 having a glass plate 9 attached to the opening 8 is prepared.
Is held at the bottom, and the cap 7 is filled with about 90% of the fluorine-based inert liquid 10 with respect to the capacity of the cap 7.

The stem 2 having the semiconductor laser chip 4 is aligned with the opening of the cap 7, and the cap 7 and the stem 4 are welded and sealed.

Alternatively, the following method may be used. First, the stem 2 having the semiconductor laser chip 4 and the cap 7 are welded without injecting the fluorine-based inert liquid 10 therein.
At this time, the stem 2 and the cap 7 are not completely welded, and an unwelded portion enough to exhaust the air in the cap 7 remains. Next, the cap 7 to which the stem 2 is attached is placed in a vacuum container (not shown), and the vacuum container is evacuated to 1 Torr or less. With this, the cap 7
The inside air is exhausted, and the inside of the cap 7 is reduced in pressure.
Thereafter, the cap 7 with the stem 2 attached is immersed in a fluorine-based inert liquid. Since the inert liquid flows from the unwelded portion between the cap 7 and the stem 2, the flow of the appropriate amount of the fluorine-based inert liquid into the cap 7 is prevented by the glass plate 9.
After the cap 7 is filled with a predetermined amount of the inert liquid while observing through, the cap 7 with the stem 2 attached is pulled up from the fluorine-based inert liquid. afterwards,
After leaving the inside of the cap 7 completely returned to the atmospheric pressure, the unwelded portion is welded.

Hereinafter, the present invention will be described more specifically by showing an example in which the present invention is applied to an optical fiber coupling module.

FIG. 4 shows a schematic cross section of the optical fiber coupling module 21. Optical fiber coupling module 21
Has a stem 22, a copper block 23 provided on one surface of the stem 22, and a semiconductor laser chip 24 die-bonded to a part of the copper block 23. The stem 22 is provided with a lead wire 25 and is connected to the semiconductor light emitting chip 24 via a wire 26. The optical fiber coupling module 21 has a cap 28 provided so as to surround the semiconductor light emitting chip 24 and the copper block 23. The cap 28 has an opening 27 into which the optical fiber 35 is inserted. The optical fiber 35 includes a ferrule 36 and a ferrule receiver 37.
With this, it is fixed to the cap 27. Cap 2
7 and the stem 23, the space 31
, The insulating inert liquid 30 is sealed.

FIG. 5 is a graph showing operating characteristics of an optical fiber coupling module 21 using a semiconductor laser having a strained multiple quantum well type stripe structure as the semiconductor light emitting chip 24. The semiconductor light emitting chip 24 is made of InGaP / AlG
Active layer having multiple quantum well structure composed of aInP and AlGa
And a cladding layer made of InP.
It emits red light having a wavelength of 0 nm. The curve shown by the solid line indicates the operating characteristics of the optical fiber coupling module 21. The curve shown by the broken line shows the operating characteristics of the optical fiber coupling module manufactured without sealing the insulating inert liquid for comparison. As is clear from the figure, high power is achieved by enclosing the insulating inert liquid. Specifically, when a current of 800 mA flows through the optical fiber coupling module, an output of 200 mW is obtained in the module not filled with the insulating inert liquid, but an output of 270 mW is obtained in the optical fiber coupling module 21. Such output improvement is explained for the following reasons.

First, since the entire semiconductor laser chip 28 is efficiently cooled by the insulating inert liquid 30, the temperature of the semiconductor laser chip 28 is prevented from rising. Thereby, the COD level (Catastrophic Opti
cal Damage) and deterioration of the end face of the semiconductor laser chip 28 can be prevented. Further, since the recombination efficiency is improved, the slope efficiency (the slope of the illustrated graph) is improved.

Further, since the end face of the semiconductor laser chip 28 is in contact with the insulating inert liquid, the reflectivity at the end face is improved. This reduces the threshold current. Specifically, the threshold current has been reduced from 450 mA to 400 mA.

FIG. 6 shows the results of a life test of the optical fiber coupling module 21. For comparison, the broken line shows the test result of the module without filling the insulating inert liquid. As is clear from the figure, in the optical fiber coupling module 21 of the present invention, the output does not decrease even after 100 hours. In addition, since the COD level is improved, it can be seen that a higher output is obtained as compared with a module in which the insulating inert liquid is not filled. On the other hand, conventional modules
It can be seen that a high output cannot be obtained and the speed of deterioration is high.

(Embodiment 2) FIG. 7 shows a cross section of a semiconductor light emitting device 41 according to a second embodiment of the present invention. In the semiconductor light emitting device 41, the structure of the cap 42 is different from that of the semiconductor light emitting device 1 of the first embodiment. A concave portion 46 is provided on the upper surface 43 of the cap 42, and a glass plate 44 is provided in an opening 49 of the concave portion 46. Cap 42
The position of the upper surface 43 is higher than the position of the glass plate 44 by a distance 45, and the surface of the insulating inert liquid 10 is
It is higher than 4. The glass plate 44 has a surface 48 on the semiconductor light emitting chip 4 side, and the entire surface 48 is in contact with the insulating inert liquid 10. As a result, the insulating inert liquid 10 optically continuously connects the entire surface of the light emitting end face 47 of the semiconductor laser chip 3 and the entire surface 48 of the glass plate 44. Since the space 12 is provided at a position higher than the window 44, even if the semiconductor light emitting element 41 is slightly inclined, the space 12 is formed between the light emitting end face 47 and the window 44 due to the movement of the liquid surface of the insulating inert liquid 10. Will not move.

The semiconductor light emitting device 4 having such a structure
1 is that the light emitted from the semiconductor laser chip 4 directly passes through the insulating inert liquid 10 and reaches the glass plate 44, so that the light is refracted at the interface between the space 12 and the insulating inert liquid 10. No dripping or scattering. In particular, even when the semiconductor light emitting element 41 vibrates during operation and the liquid surface of the insulating inert liquid 10 is disturbed, light is stably emitted without being affected by light scattering due to the disturbance of the liquid surface. be able to.

Such a structure can improve the light-collecting efficiency especially in a laser module having a semiconductor laser and an optical lens. FIG. 8 shows a cross section of a semiconductor light emitting device 51 having an optical lens 52. Semiconductor light emitting element 51
Is a glass window 44 of the semiconductor light emitting device 41 shown in FIG.
Has an optical lens 52 instead.

In the semiconductor light emitting device 51, the cap 4
A concave portion 46 is provided on the upper surface 43 of the
Is provided with an optical lens 52 in the lower part of the lens. Cap 4
The position of the upper surface 43 is higher than the position of the optical lens by a distance 45, and the liquid surface of the insulating inert liquid 10 is higher than the optical lens 52. The optical lens 52 is
It has a surface 53 on the semiconductor light emitting chip 4 side, and the entire surface 53 is in contact with the insulating inert liquid 10. as a result,
The insulating inert liquid 10 optically continuously connects the entire surface of the light emitting end face 47 of the semiconductor laser chip 3 and the entire surface 53 of the optical lens 52. Insulating inert liquid 10
Is optically and continuously connected between the entire surface of the light emitting end face 47 of the semiconductor laser chip 3 and the optical lens 52.

When the semiconductor laser chip 4 emits light of 780 nm at an angle of 30 degrees in the vertical direction and 10 degrees in the horizontal direction, 95% of the so-called emitted laser light amount when the laser light intensity becomes 1 / e ² is calculated. The NA of the optical lens 52 that can be received was obtained. The calculation formula used is NA = 2 sin (θ / 2), where θ is the emission angle.

The calculation results are shown in Table 1 below.

[0039]

[Table 1]

The refractive index of the insulating inert liquid 10 is 1.24.
It can be seen that 95% of the light emitted from the semiconductor laser chip 4 is collected when the NA of the lens is 0.42 and 0.36 at the time of 1.4 and 1.4, respectively. On the other hand, when filled with air instead of the insulating inert liquid 10, the refractive index becomes 1, which indicates that an optical lens having an NA of 0.52 is required. This is because the semiconductor constituting the semiconductor laser chip 4 comes into contact with the insulating inert liquid 10 having a higher refractive index than that of air.
This is because the substantial exit angle from the light beam becomes small.

Therefore, a lens having a small aperture can be used by reducing the emission angle, and the semiconductor light emitting element 51 can be downsized. Also, N
A lens with a large A is generally expensive, but according to the present invention, an inexpensive lens with a small NA can be used, so that a semiconductor light emitting device can be manufactured at low cost.

As described above, one of the features of the semiconductor light emitting device shown in this embodiment is that the space between the window formed in the cap and the semiconductor laser chip is continuously filled with the insulating inert liquid. . Such features of the present embodiment can be realized by another structure as described below.

FIG. 9A shows a cross section of the semiconductor light emitting device 61. FIG. 9B shows a cross section in a direction perpendicular to FIG. 9A. The semiconductor light emitting element 61 includes the cap 7
Has an inner cylinder 62 inside. The inner cylinder 62 has an inner space that does not block light emitted from the semiconductor laser chip 4. The space between the cap 7 and the inner cylinder 62 is filled with a microcapsule 64. Cap 7 and stem 2
Is completely filled with the insulating inert liquid 63.

The microcapsules 64 have shrinkage to external force. Specifically, it is made of a balloon containing air or an inert gas inside, or a foamable resin having micropores. When the insulating inert liquid 63 expands, the volume of the microcapsules 64 itself decreases, Cap 7
Is prevented from exploding due to expansion of the insulating inert liquid 63. In consideration of the expansion rate of the insulating inert liquid 63, the microcapsules 64 are sealed in the cap 7 so as to be able to contract at least 10% of the space enclosed by the cap 7 and the stem 2. Also, as shown in FIG.
Has a hole 65 smaller than the diameter of the microcapsule 64 so that the insulating inert liquid 63 can move between the inner space and the outer space, but the microcapsule 64 cannot move to the inner space. . Practically, microcapsules 64
Preferably has a diameter of about 1-2 mm,
The hole 65 may be smaller than that. Alternatively, hole 65
Instead, a plurality of slits 66 having a width smaller than the diameter of the microcapsules 64 may be provided.

According to the above-described structure, since there is no space in the cap 7, no insulation is always provided between the emission surface 12 of the semiconductor laser chip 4 and the window 7 no matter how violently the semiconductor light emitting element 61 is vibrated. Filled with active liquid 63. Therefore,
The semiconductor light emitting element 61 can stably emit light without being affected by light scattering or the like due to disorder of the liquid level of the insulating inert liquid 63. Particularly, when the semiconductor light emitting element 61 is used in a state of high vibration, Are suitable.

FIG. 10 shows a cross section of still another semiconductor light emitting device 71. The semiconductor light emitting device 71 has a cap 72 having an inlet 73 and an outlet 74. Entrance 7
3 and outlet 74 are connected to pump 75
Are connected to the discharge port and the suction port. The inside of the cap 72 and the tube 76 is filled with an insulating inert liquid 77. A cooler 78 for keeping the insulating inert liquid 77 flowing in the pipe 76 at a constant temperature is inserted in the middle of the pipe 76. The pump 7 and the cooler 78 allow the cap 7
The insulating inert liquid 77 in 2 is circulated at a constant flow rate while maintaining a predetermined temperature. The flow rate is determined so that the semiconductor laser chip 4 is sufficiently cooled and no cavity is formed in the insulating inert liquid 77. In the semiconductor light emitting element 71, the semiconductor laser chip 4 is always in contact with the insulating inert liquid 77 kept at a constant temperature, and heat generated by emitting light is radiated by the insulating inert liquid 77. Therefore, the semiconductor laser chip 4 is always kept at a constant temperature during operation. Insulating inert liquid 77
Is kept at a constant temperature and does not thermally expand, so there is no need to provide a space in the cap 72.

According to such a structure, there is obtained an advantage that the emission wavelength and the output are very stable during the operation of the semiconductor light emitting device 71. In particular, this structure is suitable for a high output semiconductor light emitting device having an output of 1 W or more.

In the above embodiment, the semiconductor light emitting devices 61 and 71 having the glass plate 9 provided in the opening 8 have been described. However, an optical lens may be provided instead of the glass plate 9. Further, although the semiconductor light emitting device having the semiconductor laser chip has been described in the above embodiment, it is understood that the present invention can be applied to a light emitting diode.

(Embodiment 3) FIG. 11 shows a schematic cross section of a semiconductor light emitting device 81 according to a third embodiment of the present invention. The semiconductor light emitting element 81 includes a semiconductor laser chip 83,
It has a light wavelength conversion element 84 and an optical lens 85. A housing 86 covers a stem 82 having a semiconductor laser chip 83 and a light wavelength conversion element 84. An opening 92 is provided on a side surface of the housing 86, and an optical lens 85 is provided. The housing 86 is filled with an insulating inert liquid 87 except for a space 88. Semiconductor light emitting chip 83
Outgoing end face 88, the incoming end face 89 of the light wavelength converting element 84, the outgoing end face 90 of the light wavelength converting element, and the surface 91 of the optical lens.
Are continuously filled with an insulating inert liquid 87. The space 86 functions to prevent the housing 86 from bursting when the insulating inert liquid 87 thermally expands, as described in the first embodiment. The optical wavelength conversion element 84 is specifically a second-harmonic generation element, and the semiconductor laser chip 8
The light emitted from 3 is converted by a light wavelength conversion element 84 into light having a half wavelength. Such an optical wavelength conversion element is known, for example, Japanese Patent Application Publication No.
No. 167,531 and U.S. Pat. No. 5,205,904.

FIG. 12 is a perspective view of a known optical wavelength conversion element 84 used in this embodiment. This light wavelength conversion element 84 is formed in a substrate 93 made of LiTaO ₃ . An optical waveguide 94 is formed in the substrate 93. Further, a domain-inverted layer 95 and a non-domain-inverted layer 96 are periodically provided in the substrate 93 in order to perform pseudo phase matching in a direction perpendicular to the optical waveguide 94. The optical waveguide 94 is formed by immersing the substrate 93 in phosphoric acid and performing proton exchange. The fundamental wave P1 incident from the end face 97 of the optical waveguide 94 is converted into a harmonic P2 in the domain-inverted layer 95 and amplified in the non-localized pole-inverted layer 96. According to the optical wavelength conversion element 84,
A fundamental wave P1 having a wavelength of 0.84 μm is output at 40 mW and the end face 9
7, a harmonic P2 having a wavelength of 0.42 μm is obtained from the end face 98 with an output of 2 mW. End faces 97 and 98 are rectangles of 1.4 μm × 2 μm.

When the light wavelength conversion element 84 is used, it is possible to obtain blue light which is difficult to emit light, but the conversion efficiency is about 5%. Therefore, it is necessary to make the laser light emitted from the semiconductor laser chip 83 incident on the light wavelength conversion element 84 as efficiently as possible. According to the semiconductor light emitting device 81 of the present invention, the light from the semiconductor laser chip 83 can be efficiently guided to the wavelength conversion device 84 and further condensed by the optical lens 85 as described below.

The light emitted from the semiconductor laser chip 83 has an emission angle α as described in the second embodiment, and spreads and travels. This is the semiconductor laser chip 8
This is because light emitted based on Snell's law is refracted at the end face 88 because 3 is in contact with air having a smaller refractive index than the semiconductor. Therefore, in order to make the light from the semiconductor laser chip 83 incident on the light wavelength conversion element 84 as much as possible, the exit end face 88 of the semiconductor laser chip 83 and the incidence end face 89 of the light wavelength conversion element 84 should be as close as possible. preferable.

FIG. 13 shows that the amount of light (coupling efficiency) at which the laser beam from the semiconductor laser chip 83 enters the end face 97 of the waveguide provided on the incidence face 89 of the light wavelength conversion element 84 is 50%.
At this time, the relationship between the distance x between the end face 88 of the semiconductor laser chip 10 and the incident end face 89 of the light wavelength conversion element 84 and the emission angle α of the semiconductor laser is shown. As shown in FIG.
It can be seen that if the emission angle α is small, a coupling efficiency of 50% can be obtained even if the distance x increases.

When the medium in contact with the end face 88 of the semiconductor laser chip 83 is air (refractive index 1) and insulating inert liquid (refractive indexes 1.24 and 1.4), the distance to the emission angle α of about 20 degrees Table 2 below shows the relationship of x.

[0055]

[Table 2]

It can be seen that by using an insulating inert liquid having a high refractive index, the distance x can be 1.6 to 2 times longer than when the semiconductor laser chip 83 is in contact with air. Conventionally, it has been difficult to arrange the semiconductor laser chip 83 and the optical wavelength conversion element 84 at an interval of 10 μm or less. However, the arrangement interval can be lengthened by using an insulating inert liquid.
And the optical wavelength conversion element 84 can be efficiently arranged.

The alignment between the semiconductor laser chip 83 and the light wavelength conversion element 84 is performed by setting the inside of the housing 86 to the insulating inert liquid 8.
It is easier to do without filling with 7. First, when the casing 86 is filled with the insulating inert liquid 87, the arrangement relationship to be filled by the semiconductor laser chips 83 is calculated by calculation. Next, the insulating inert liquid 8
If the housing 86 is not filled at 7, the optical coupling efficiency obtained at that position is determined. The semiconductor laser chip 83 and the semiconductor laser chip 83 are actually arranged so that the inside of the housing 86 is not filled with the insulating inert liquid 87 and the calculated optical coupling efficiency is obtained. Finally, the inside of the housing 86 is filled with the insulating inert liquid 87.

According to the semiconductor light emitting device 81 of this embodiment,
As described in the second embodiment, the emission angle θ of the light incident on the optical lens 85 can also be reduced.

The half-value angle at which 50% of the intensity of the light emitted from the light wavelength conversion element 84 in the central axis direction is obtained is θ 1
When the effective angle at which 95% of the light emitted from the emission end face 90 of the light wavelength conversion element 84 is taken into the optical lens 85 is θ2, the necessary calculation result of the aperture diameter NA of the optical lens 85 is as follows. Is shown in Table 3.

[0060]

[Table 3]

Since the conversion efficiency of the light wavelength conversion element 84 is low and all the light from the output end face 90 needs to be incident on the optical lens 85 in practical use, the value obtained when 95% of the light emitted from the output end face 90 is captured. Is shown.

When the space between the light wavelength conversion element 89 and the optical lens 85 is filled with air (refractive index n = 1),
An optical lens having an NA of 0.65 is required. Such an optical lens is very expensive because mass production is difficult. On the other hand, according to the present invention, a relatively inexpensive optical lens having an NA of about 0.4 to 0.5 can be used, so that an optical semiconductor element that emits blue light at low cost can be manufactured. Further, the optical wavelength conversion element 84 can be accurately and easily arranged on the semiconductor laser chip 83.

As described in the first embodiment, in the semiconductor light emitting element 81, the semiconductor light emitting chip 83 and the light wavelength conversion element 84 are covered with the insulating inert liquid 87, so that the semiconductor light emitting chip 83 operates. The heat generated therein is efficiently dissipated to the insulating inert liquid 87. Further, since the insulating inert liquid 87 also functions as a protective film, it is possible to prevent the surfaces of the semiconductor light emitting chip 83 and the optical wavelength conversion element 84 from being oxidized and the characteristics from being deteriorated.

[0064]

According to the present invention, by encapsulating an insulating inert liquid, for example, a fluorine-based inert liquid, in a cap in a package, it becomes possible to cool the entire semiconductor light emitting element chip, When the light output of the light emitting element increases, a stable operation with high output is realized, and the reliability of the element is improved. In particular, in the conventional high power semiconductor laser, the chip is mounted face down, but in the present invention, face up mounting is also possible.

Since the space is provided in the cap of the package even if the insulating inert liquid expands due to a change in ambient temperature, there is no possibility that the cap will burst. Therefore, the semiconductor light emitting device of the present invention can be used in a wide temperature range.

By providing a concave portion in a part of the cap and providing a glass plate or an optical lens at the bottom of the concave portion, the gap between the glass plate or the optical lens and the semiconductor light emitting element chip is always filled with the insulating inert liquid. Therefore, the spread of the light emitted from the semiconductor light emitting element chip is suppressed,
Light can be emitted out of the package with high efficiency.

In particular, since an optical lens having a small NA can be used, a compact and low-cost light emitting element can be obtained. In addition, stable emission can be obtained without disturbing the emitted light even in a use state with a lot of vibration.

Further, when the light wavelength conversion element is provided between the semiconductor light emitting element and the optical lens, alignment mounting of optical coupling between the semiconductor laser chip and the light wavelength conversion element becomes easy, and the NA of the condenser lens is reduced. A smaller optical output can be obtained at a lower cost than conventional ones by improving the optical coupling efficiency.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of a semiconductor light emitting device according to a first embodiment of Example 1.

FIG. 2 is a diagram showing the thermal conductivity of a fluorine-based inert liquid and nitrogen gas / air due to natural convection.

FIG. 3 is a diagram showing the relationship between the density and temperature of the fluorine-based inert liquid used in the first embodiment.

FIG. 4 is a diagram showing a cross section of the optical fiber coupling module according to the first embodiment;

FIG. 5 is a diagram showing operation characteristics of the optical fiber coupling module.

FIG. 6 is a diagram showing a life test result of the optical fiber coupling module.

FIG. 7 is a view showing a cross section of the semiconductor light emitting device according to the second embodiment of Example 1;

FIG. 8 is a view showing a cross section of the semiconductor light emitting device according to the third embodiment of Example 1;

FIG. 9 is an explanatory diagram of a semiconductor light emitting device.

FIG. 10 is a diagram showing a cross section of the semiconductor light emitting device according to the second embodiment of Example 2.

FIG. 11 is a diagram showing a surface of a semiconductor light emitting device according to a third embodiment.

FIG. 12 is a perspective view showing an optical wavelength conversion element used for the semiconductor light emitting element shown in FIG.

FIG. 13 is a diagram showing a relationship between an angle of light emitted from the semiconductor light emitting chip and a distance required for the light wavelength conversion element to receive light at a predetermined intensity from the semiconductor light emitting chip.

FIG. 14 is a diagram showing a cross section of a conventional semiconductor light emitting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor light emitting element 2 Stem 3 Copper block 4 Semiconductor laser chip 5 Lead wire 6 Wire wire 7 Cap 8 Opening 9 Glass plate 10 Insulating inert liquid 11 Space

Continuation of the front page (72) Inventor Seiji Onaka 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-1-179483 (JP, A) JP-A-2-67782 (JP) JP-A-57-141986 (JP, A) JP-A-58-201387 (JP, A) JP-A-2-187016 (JP, A) JP-A-4-312962 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01S 5/00-5/50 G02F 1/37 H01L 33/00

Claims (7)

(57) [Claims] 1. A semiconductor light emitting chip having a light emitting surface, a cap enclosing the semiconductor light emitting chip, and an insulating inert liquid filled so as to leave a space inside the cap , wherein the cap has Has a recess with an opening at the bottom
And a transparent plate provided in the opening and made of a material that transmits light emitted by the semiconductor light emitting element. The insulating property is provided between the entire surface of the light emitting surface and the entire surface of the transparent plate.
A semiconductor light emitting device that is filled with an inert liquid . 2. The semiconductor light emitting device according to claim 1, wherein the transparent plate is an optical lens. Includes a semiconductor light emitting chip having a 3. A light-emitting surface, the cap enclosing the semiconductor light-emitting chips, an insulating inert liquid filled so as to leave a space in the interior of the cap, the said semiconductor light emitting The device was further encapsulated in the cap
A microcapsule and the microcapsule from the light emitting surface
Means for preventing the emitted light from being blocked.
And a semiconductor light emitting device , wherein the space is included in a microcapsule . 4. The wavelength conversion of light from a semiconductor light emitting chip.
4. The method according to claim 1, further comprising an optical wavelength conversion element.
A semiconductor light emitting device according to any one of the above . 5. The semiconductor light emitting device according to claim 1, wherein said insulating inert liquid is a fluorine-based inert liquid. 6. The semiconductor light emitting device according to claim 5, wherein said insulating inert liquid is a fluorine-based inert liquid containing no chlorine. 7. The semiconductor light emitting device according to claim 1, wherein a ratio of a volume of the space to a volume of the insulating inert liquid is about 1: 9.