阅读说明：本技术 半导体激光装置以及分析装置 (Semiconductor laser device and analyzer ) 是由 松滨诚 粟根悠介 有本公彦 伊关博臣 桝田真太郎 于 2020-03-03 设计创作，主要内容包括：本发明提供半导体激光装置以及分析装置。一种半导体激光装置,用于光学分析,能够减小检测半导体激光元件的温度的温度检测元件的测定误差,高精度地进行半导体激光元件的温度控制,其中,具备：半导体激光元件(2)；温度检测元件(3),检测半导体激光元件(2)的温度；输出端子(T1、T2),将温度检测元件3的输出向外部输出；布线(L1、L2),将温度检测元件(2)与输出端子(T1、T2)电连接；以及热容量增大部(7),夹设在温度检测元件(3)与输出端子(T1、T2)之间,与布线(L1、L2)的至少一部分接触而增大布线(L1、L2)的热容量。(The invention provides a semiconductor laser device and an analysis device. A semiconductor laser device for optical analysis capable of reducing measurement errors of a temperature detection element for detecting the temperature of a semiconductor laser element and controlling the temperature of the semiconductor laser element with high accuracy, comprising: a semiconductor laser element (2); a temperature detection element (3) that detects the temperature of the semiconductor laser element (2); output terminals (T1, T2) for outputting the output of the temperature detection element 3 to the outside; wiring lines (L1, L2) for electrically connecting the temperature detection element (2) and the output terminals (T1, T2); and a heat capacity increasing unit (7) interposed between the temperature detection element (3) and the output terminals (T1, T2) and contacting at least a part of the wirings (L1, L2) to increase the heat capacity of the wirings (L1, L2).)

1. A semiconductor laser device for optical analysis, comprising:

a semiconductor laser element;

a temperature detection element that detects a temperature of the semiconductor laser element;

an output terminal for outputting an output of the temperature detection element to the outside;

a wiring electrically connecting the temperature detection element and the output terminal; and

and a heat capacity increasing section interposed between the temperature detection element and the output terminal, and contacting at least a part of the wiring to increase the heat capacity of the wiring.

2. The semiconductor laser device according to claim 1,

the semiconductor laser element is a quantum cascade laser.

3. The semiconductor laser device according to claim 1 or 2,

the semiconductor laser device further includes:

a cooling mechanism on which the semiconductor laser element is mounted, for cooling the semiconductor laser element; and

and a control unit that controls the cooling mechanism using the temperature detected by the temperature detection element.

4. The semiconductor laser device according to claim 1 or 2,

the semiconductor laser device further includes a substrate interposed between the cooling mechanism and the semiconductor laser element,

the heat capacity increasing portion is in contact with the substrate.

5. The semiconductor laser device according to claim 1 or 2,

the heat capacity increasing portion is formed of silicon.

6. The semiconductor laser device according to claim 4,

the wiring is embedded in the substrate and is formed on the substrate,

the substrate functions as the heat capacity increasing section.

7. The semiconductor laser device according to claim 4 or 6,

the substrate is a laminated ceramic substrate,

the wiring is formed using the wiring of the laminated ceramic substrate.

8. The semiconductor laser device according to claim 1 or 2,

the semiconductor laser device further includes a light shielding portion that faces an end surface opposite to the light emitting surface of the semiconductor laser element and shields light leaking from the end surface.

9. The semiconductor laser device according to claim 1 or 2,

the temperature detection element is provided to face an end surface of the semiconductor laser element opposite to the light emitting surface.

10. An analysis device for analyzing a component to be measured contained in a fluid, comprising:

a measurement unit into which the fluid is introduced;

the semiconductor laser device according to any one of claims 1 to 9, wherein the measurement unit is irradiated with laser light;

a photodetector for detecting the laser beam having passed through the measuring unit; and

and an analysis unit for analyzing the measurement target component using a detection signal of the photodetector.

Technical Field

The present invention relates to a semiconductor laser device and an analysis device for optical analysis.

Background

Conventionally, in a gas analyzer using a semiconductor laser element, for example, since a wavelength variation of laser light emitted from the semiconductor laser element affects analysis accuracy, the temperature of the semiconductor laser element, which is one of factors of the wavelength variation, is controlled to a desired temperature.

For example, in patent document 1, a temperature control unit having a peltier element, a support substrate, and the like is mounted with a temperature detection unit such as a semiconductor laser element and a thermistor, and the temperature control unit is controlled based on the temperature obtained by the temperature detection unit. Thus, the temperature of the semiconductor laser element is controlled to a desired temperature, and wavelength fluctuation of the laser light is suppressed. In the semiconductor laser light source of patent document 1, a semiconductor laser element, a temperature detection unit, and a temperature control unit are provided in an internal space formed by a base member and a cover member. The plurality of pin terminals provided so as to penetrate the base member from the outside of the base member toward the internal space are electrically connected to the semiconductor laser element, the temperature detection unit, and the temperature control unit, respectively, via conductive leads.

However, as the ambient temperature of the semiconductor laser light source changes, the temperature of the pin terminal provided in the base member changes, and heat is transferred from the pin terminal to the temperature detection unit through the conductive wire. Then, the temperature of the temperature detection portion fluctuates due to heat from the conductive wire. As a result, a measurement error occurs in the temperature of the semiconductor laser device, and it is difficult to control the temperature of the semiconductor laser device with high accuracy.

Patent document 1: international publication No. 2013/084746

Disclosure of Invention

The present invention has been made to solve the above-described problems, and a main object of the present invention is to reduce a measurement error of a temperature detection element for detecting a temperature of a semiconductor laser element, and to control the temperature of the semiconductor laser element with high accuracy.

That is, the semiconductor laser device according to the present invention is used for optical analysis, and includes: a semiconductor laser element; a temperature detection element that detects a temperature of the semiconductor laser element; an output terminal for outputting an output of the temperature detection element to the outside; a wiring electrically connecting the temperature detection element and the output terminal; and a heat capacity increasing section interposed between the temperature detection element and the output terminal, and contacting at least a part of the wiring to increase a heat capacity of the wiring.

According to such a semiconductor laser device, since the heat capacity increasing section that increases the heat capacity of the wiring connecting the temperature detection element and the output terminal is provided, the amount of heat that is transferred to the wiring and flows into the temperature detection element can be reduced. As a result, the temperature of the semiconductor laser element can be detected with high accuracy by the temperature detection element, and the temperature of the semiconductor laser element can be controlled with high accuracy.

For example, in order to be applied to optical analysis such as infrared spectroscopic analysis, the semiconductor laser device is preferably a quantum cascade laser. Here, the quantum cascade laser consumes more power than a normal semiconductor laser by one order of magnitude or more, and is likely to cause a temperature change, and therefore is greatly affected by frequency fluctuation. According to the present invention, since the temperature of the quantum cascade laser can be controlled with high accuracy, frequency fluctuation due to temperature change can be suppressed, and optical analysis can be performed with high accuracy.

As a specific embodiment for adjusting the temperature of the semiconductor laser element, the semiconductor laser device preferably further includes: a cooling mechanism on which the semiconductor laser element is mounted, for cooling the semiconductor laser element; and a control unit that controls the cooling mechanism using the temperature detected by the temperature detection element.

When the cooling mechanism is directly mounted with the semiconductor laser element, there is a possibility that the difference between the thermal expansion coefficient of the cooling mechanism and the thermal expansion coefficient of the semiconductor laser element causes deformation of both of them or a gap is formed between both of them to inhibit heat transfer.

Therefore, it is considered that the semiconductor laser device further includes a substrate interposed between the cooling mechanism and the semiconductor laser element. The thermal expansion coefficient of the substrate is considered to be between that of the cooling mechanism and that of the semiconductor laser element. As a material of the substrate, ceramics such as aluminum nitride (AlN) and silicon carbide (SiC) can be used.

In order to increase the heat capacity of the wiring and positively make the temperature of the wiring equal to the temperature of the semiconductor laser element, the heat capacity increasing portion is preferably in contact with the substrate. In this case, by forming the heat capacity increasing portion so as to cover a part of the wiring, the volume of the heat capacity increasing portion can be made smaller than that of the entire wiring, temperature adjustment by heat transfer from the substrate becomes easy, and the time until the temperature of the wiring is stabilized (for example, warm-up time) can be shortened.

Preferably, the heat capacity increasing portion is formed of silicon, which is an insulating material. According to this configuration, the heat capacity can be increased without hindering the transmission of the electrical signal of the wiring. Further, since silicon has flexibility, it is difficult to break the wiring, and it also has a function of protecting the wiring.

In order to form the heat capacity increasing section using an existing structure, it is preferable that the wiring is embedded in the substrate, and the substrate functions as the heat capacity increasing section.

Here, the substrate is a laminated ceramic substrate, and the wiring is formed using the wiring of the laminated ceramic substrate.

Light may leak from an end surface opposite to the light emitting surface of the semiconductor laser element, and the leaked light may become stray light. Therefore, in order to reduce stray light, it is preferable that the semiconductor laser device further include a light shielding portion that faces an end surface opposite to the light emitting surface of the semiconductor laser element and shields light leaking from the end surface.

In addition, by providing the temperature detection element so as to face the end surface on the opposite side of the light emitting surface of the semiconductor laser element, stray light can be reduced by the temperature detection element.

An analysis device according to the present invention analyzes a component to be measured contained in a fluid, and includes: a measurement unit into which the fluid is introduced; the semiconductor laser device irradiating the measurement unit with laser light; a photodetector for detecting the laser beam having passed through the measuring unit; and an analysis unit that analyzes the measurement target component using a detection signal of the photodetector.

According to such an analysis device, since the temperature of the semiconductor laser element can be controlled with high accuracy, the component to be measured contained in the fluid can be analyzed with high accuracy.

According to the present invention thus constituted, measurement errors of the temperature detection element for detecting the temperature of the semiconductor laser element can be reduced, and temperature control of the semiconductor laser element can be performed with high accuracy.

Drawings

Fig. 1 is a schematic view showing an entire exhaust gas analyzer using a semiconductor laser device according to the present embodiment.

Fig. 2 is a plan view schematically showing the entire structure of the semiconductor laser device according to this embodiment.

Fig. 3 is a cross-sectional view schematically showing the entire structure of the semiconductor laser device according to this embodiment.

Fig. 4 is a plan view schematically showing the entire structure of the semiconductor laser device according to the modified embodiment.

Fig. 5 is a cross-sectional view schematically showing the entire structure of the semiconductor laser device according to the modified embodiment.

Fig. 6 is a plan view schematically showing the entire structure of the semiconductor laser device according to the modified embodiment.

Fig. 7 is a cross-sectional view schematically showing the entire structure of the semiconductor laser device according to the modified embodiment.

Description of reference numerals:

100: a semiconductor laser device; 2: a semiconductor laser element; 3: a temperature detection element; t1, T2: an output terminal; l1, L2: wiring; 7: an increased heat capacity section; 4: a cooling mechanism; COM: a control unit; 5: a substrate; 5a, 5 b: the wiring of the ceramic substrate is laminated.

Detailed Description

An embodiment of a semiconductor laser device according to the present invention will be described below with reference to the drawings.

As shown in fig. 1, a semiconductor laser device 100 according to the present embodiment is used, for example, for measuring a component to be measured (for example, CO) in an exhaust gas discharged from an internal combustion engine₂、H₂O、NO、NO₂、N₂O、NH₃Hydrocarbon components such as HC, oxygen-containing hydrocarbon components such as HCHO). Here, the exhaust gas analyzer 10 includes a multiple reflection type measurement cell 11 into which the exhaust gas is introduced, a semiconductor laser device 100 that irradiates the measurement cell 11 with the laser beam X, a photodetector 12 that detects the laser beam X after passing through the measurement cell 11, and an analysis unit 13 that analyzes the measurement target component using a detection signal of the photodetector 12. The measurement unit 11 is not limited to the multiple reflection type, and may be a single reflection type or a single path type not using reflection.

Specifically, the semiconductor laser device 100 emits laser light X having an oscillation wavelength including an absorption wavelength of a component to be measured, and as shown in fig. 2 and 3, includes: a semiconductor laser element 2; a temperature detection element 3 for detecting the temperature of the semiconductor laser element 2; a cooling mechanism 4 on which the semiconductor laser element 2 and the temperature detection element 3 are mounted, for cooling the semiconductor laser element 2; a substrate (submount)5 provided between the semiconductor laser element 2 and the temperature detection element 3 and the cooling mechanism 4; and an airtight container 6 for storing them.

The semiconductor Laser element 2 is, for example, a Distributed Feedback Laser (DFB Laser) that emits Laser light X having an infrared wavelength, and in particular, in the present embodiment, is a quantum cascade Laser in which a plurality of well layers are connected in multiple stages and light is emitted by optical transition between sub-bands formed in the quantum wells.

The temperature detection element 3 detects the temperature of the semiconductor laser element 2 by detecting the temperature of the substrate 5 on which the semiconductor laser element 2 is mounted. The temperature detection element 3 of the present embodiment is a thermistor and is provided in the vicinity of the semiconductor laser element 2 in order to reduce the temperature difference with the semiconductor laser element 2. The temperature detection element 3 in fig. 2 is provided on the side of the semiconductor laser element 2, but may be provided at another position. Further, by disposing the temperature detection element 3 to face the rear end surface opposite to the light emitting surface of the semiconductor laser element 2, light leaking from the rear end surface of the semiconductor laser element 2 can be blocked and stray light can be reduced.

The cooling mechanism 4 is formed using a peltier element, and its upper surface is a heat absorbing surface. The substrate 5 is disposed in contact with the heat absorbing surface. The cooling mechanism 4 is controlled by a control unit COM that obtains the temperature detected by the temperature detection element 3. Specifically, the control unit COM controls the power supplied to the peltier element using the temperature detected by the temperature detection element 3 so that the temperature detected by the temperature detection element 3 becomes a desired temperature.

The substrate 5 is a ceramic substrate such as aluminum nitride (AlN) or silicon carbide (SiC). A semiconductor laser element 2 and a temperature detection element 3 are provided on the upper surface of the substrate 5. Metal layers 51, 52, and 53 electrically connected to the elements 2 and 3 are formed on the upper surface of the substrate 5.

The hermetic container 6 forms a hermetic space such as a butterfly package, for example, and a light guide portion 61 for guiding the laser light X to the outside is formed on a side wall facing the light emitting surface of the semiconductor laser element 2. The light guide-out portion 61 is provided with an optical window member 62, and the optical window member 62 is inclined slightly (for example, by 2 degrees) so as not to return the laser light X reflected by the optical window member 62 to the semiconductor laser element 2 again.

The airtight container 6 is provided with output terminals T1 and T2 for outputting the output of the temperature detection element 3 to the outside, and power supply terminals T3 and T4 for supplying power to the semiconductor laser element 2. These output terminals T1 and T2 and the power supply terminals T3 and T4 are arbitrarily determined depending on which of the temperature detection element 3 and the semiconductor laser element 2 is connected. The airtight container 6 is also provided with power supply terminals T5 and T6 for supplying power to the peltier elements of the cooling mechanism 4.

The output terminals T1 and T2 are connected to temperature detection wires L1 and L2 electrically connected to the temperature detection element 3. Two output terminals T1 and T2 are provided, one output terminal T1 is connected to a wiring L1 connected to the metal layer 51, the metal layer 51 is electrically connected to one electrode of the temperature detection element 3, the other output terminal T2 is connected to a wiring L2, and the wiring L2 is electrically connected to the other electrode of the temperature detection element 3. These wirings L1 and L2 are gold wires, for example.

The power supply terminals T3 and T4 of the semiconductor laser element 2 are connected to wirings L3 and L4 for the semiconductor laser element 2, which are electrically connected to the semiconductor laser element 2. There are 2 power supply terminals T3 and T4, and a wiring L3 connected to the metal layer 52 is connected to one power supply terminal T3, the metal layer 52 is electrically connected to one electrode of the semiconductor laser element 2, and a wiring L4 is connected to the other power supply terminal T4, and the wiring L4 is electrically connected to the other electrode of the semiconductor laser element 2 via the metal layer 53. Similarly, wirings L5 and L6 for the peltier element, which are electrically connected to the peltier element, are connected to the power supply terminals T5 and T6 of the peltier element.

However, the semiconductor laser device 100 according to the present embodiment further includes a heat capacity increasing unit 7, and the heat capacity increasing unit 7 is interposed between the temperature detection element 3 and the output terminals T1 and T2, and contacts at least a part of the wirings L1 and L2 for temperature detection to increase the heat capacity of the wirings L1 and L2.

The increased heat capacity section 7 is provided in contact with a part of the wiring L2 directly connecting the output terminal T2 and the temperature detection element 3. The heat capacity increasing section 7 reduces heat transfer from the output terminal T2 while maintaining electrical conduction of the wiring L2. Specifically, the heat capacity increasing section 7 is made of an insulating material, and preferably a flexible material, for example, a flexible resin such as silicon, since it covers the wiring L2. The heat capacity increasing unit 7 is provided so as to cover a part of the temperature detection wiring L2. Further, the heat capacity increasing portion 7 is also provided in contact with the substrate 5.

The increased heat capacity section 7 may be provided so as to cover at least a part of the temperature detection wiring L2 and at least a part of the temperature detection element 3. Here, when silicon is used for the increased heat capacity section 7, there is a possibility that a siloxane gas may be generated, and the siloxane gas may cause a trouble of an electronic device such as a contact failure, and therefore, the increased heat capacity section 7 made of silicon is preferable to reduce the volume thereof.

< Effect of the present embodiment >

In the semiconductor laser device 100, since the heat capacity increasing unit 7 that is in contact with the wiring L2 connecting the temperature detection element 3 and the output terminal T2 to increase the heat capacity of the wiring L2 is provided, the amount of heat that is transferred to the wiring L2 and flows into the temperature detection element 3 can be reduced. As a result, the temperature of the semiconductor laser element 2 can be detected with high accuracy by the temperature detection element 3, and the temperature of the semiconductor laser element 2 can be controlled with high accuracy. That is, the difference between the temperature detected by the temperature detection element 3 and the temperature of the semiconductor laser element 2 can be reduced, and the temperature of the semiconductor laser element 2 can be controlled with high accuracy. In the gas analyzer 10 using such a semiconductor laser device 100, it is possible to suppress fluctuations in the oscillation wavelength of the semiconductor laser element 2 and to accurately analyze the component to be measured contained in the gas.

< other embodiments >

The present invention is not limited to the above embodiments.

For example, although the output terminals T1 and T2 and the temperature detection element 3 are connected to each other through the wires L1 and L2 above the substrate 5 in the above-described embodiment, the temperature detection wires L1 and L2 may be embedded in the substrate 5 as shown in fig. 4 and 5. The substrate 5 shown in fig. 4 and 5 is a laminated ceramic substrate. In this configuration, the temperature detection wires L1 and L2 are partially constituted by the wires 5a and 5b of the laminated ceramic substrate.

Specifically, one electrode of the temperature detection element 3 is electrically connected to the wiring 5a, and the wiring 5a is electrically connected to the metal layer 54. The metal layer 54 is electrically connected to the output terminal T1 through a lead line L11 such as a gold wire. The other electrode of the temperature detection element 3 is electrically connected to a metal layer 55 formed in the vicinity of the temperature detection element 3, and the metal layer 55 is electrically connected to the wiring 5 b. The wiring 5b is electrically connected to the metal layer 56, and the metal layer 56 is electrically connected to the output terminal T2 through a lead L21 made of gold wire or the like.

By embedding a part of the wires L1 and L2 for temperature detection (particularly, the wire L2 connected to the other electrode of the temperature detection element 3) in the substrate 5 in this manner, the substrate 5 itself functions as the heat capacity increasing unit 7, and heat flowing into the temperature detection element 3 can be transferred to the wire L2.

One electrode of the semiconductor laser element 2 is electrically connected to the wiring 5c of the laminated ceramic substrate, and the wiring 5c is electrically connected to the metal layer 57. The metal layer 57 is electrically connected to the power supply terminal T3 by a lead line L31 such as a gold wire. The other electrode of the semiconductor laser element 2 is electrically connected to the power supply terminal T4 via the metal layer 58 by a wiring L4 such as a gold wire. The wirings L3 and L4 for the semiconductor laser element 2 may not be embedded in the substrate.

As a structure for embedding the wirings L1 and L2 in the substrate 5, in addition to the structure using the wirings 5a and 5b of the laminated ceramic substrate as described above, a groove may be formed in the substrate 5, and the wirings L1 and L2 may be accommodated in the groove and sealed with a resin or the like. The wirings L1 and L2 may be allowed to climb so as to contact the surface of the substrate 5.

As shown in fig. 6 and 7, a concave portion M1 for housing the semiconductor laser element 2 and a concave portion M2 for housing the temperature detection element 3 may be formed on the substrate 5. At this time, the inner surface of the recess M1 faces the rear end face of the semiconductor laser element, and functions as a light shielding portion that shields light leaking from the rear end face and reduces stray light. Here, the light-shielding surface of the light-shielding portion is slightly (for example, 2 degrees) inclined so as not to return the reflected light to the semiconductor laser element 2 again. In fig. 6 and 7, the substrate 5 is formed of a laminated ceramic substrate, but may be formed of a simple ceramic substrate.

Further, a stepped portion may be formed to face the rear end face of the semiconductor laser element 2. The height of the step is preferably higher than the height of the semiconductor laser element 2, and is preferably 2mm or more, for example.

In the above-described embodiments, the semiconductor laser device including the quantum cascade laser element has been described, but may include another semiconductor laser element (for example, a distributed reflection laser (DBR laser)).

The semiconductor laser element 2 may be driven by a Continuous Wave (CW) system, a pseudo continuous wave (pseudo CW) system, or a pulse oscillation system.

In the above embodiment, the example in which the semiconductor laser device is applied to the gas analyzer is described, but the semiconductor laser device may be applied to other optical analyzers.

The analyzer using the semiconductor laser device according to the above-described embodiment can be used, for example, for analyzing exhaust gas of automobiles, and can also analyze components (e.g., CO and CO) to be measured of various gases (e.g., ambient gas) such as the atmosphere₂、H₂O、NO、NO₂、N₂O、NH₃Hydrocarbon components such as HC, oxygen-containing hydrocarbon components such as HCHO), and liquids can also be analyzed.

The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the scope of the invention.