Miniature gas sensor

Abstract

The utility model discloses a miniature gas sensor, relates to the technical field of sensors, and solves the problem that the wavelength of a laser cannot be calibrated in real time in the prior art. The laser comprises a shell, a temperature control assembly is arranged in the shell, and a laser chip is arranged on the temperature control assembly; a main path detector chip assembly and a reference detector chip assembly are arranged in the shell, and the laser chip is located between the main path detector chip assembly and the reference detector chip assembly or on the same side of the main path detector chip assembly and the reference detector chip assembly; and a reference gas chamber is arranged between the reference detector chip assembly and the laser chip and is used for accommodating a standard target gas with a certain concentration. According to the utility model, the laser chip, the main path detector chip assembly, the reference detector chip assembly and the reference gas chamber are coupled in the shell to form the miniature gas sensor by utilizing a micromachining and manufacturing process; real-time calibration of wavelength and gas concentration detection are realized by combining irradiation of the semiconductor laser chip with harmonic information of the reference gas chamber and the reference detector chip assembly, the size is small, the process is simple, and large-scale production is facilitated.

Description

TECHNICAL FIELD

[0001] The utility model relates to sensor technical field especially refers to a micro gas sensor. BACKGROUND

[0002] Tunable diode laser absorption spectroscopy technology is a commonly used gas analysis method, mainly using the tunable and narrow linewidth characteristics of semiconductor laser, by selecting a specific absorption spectral line of the measured gas for measurement, the interference of other gas spectrum can be excluded, and the rapid online detection of the measured gas concentration is realized. Because it has the advantages of high selectivity, high resolution, high sensitivity and not easy to be disturbed by other gases, it has been widely used in industrial process control, environmental detection, safety detection and other fields. Generally composed of laser, main road gas chamber for measurement, main road detector and peripheral signal processing circuit, etc., the separation device is more, and the volume is large. At present, the gas sensor is developing towards miniaturization and low cost, and it has important practical significance to design a micro gas sensor combined with micro processing manufacturing process.

[0003] The Chinese invention patent with publication number CN106290249A discloses a laser gas detection assembly, in particular to an integrated small laser gas detection assembly, and belongs to the technical field of detection. From top to bottom, a metal plate, a semiconductor cooler and a heat sink are sequentially connected, the metal plate is fixed with a wiring terminal as an electrical connection port, a thermistor, a semiconductor laser, a spherical quartz lens, a photodetector and a plane mirror are arranged above the metal plate; the laser emitted by the semiconductor laser is aligned with the plane mirror through the spherical quartz lens and is reflected by the plane mirror and received by the photodetector; the semiconductor laser, the semiconductor cooler, the photodetector and the thermistor are connected with the wiring terminal respectively. In the scheme, the components are packaged on the same metal substrate through the high integration TDLAS system design, so that the whole detection assembly forms an independent working laser gas sensor device.

[0004] The scheme can identify and determine the corresponding gas by emitting laser of a set wavelength through the semiconductor laser to the photodetector to convert into an electric signal. However, the scheme cannot realize real-time calibration of the wavelength of the laser emitted by the semiconductor laser according to the standard measurement parameter of the corresponding target gas to be measured, so there are problems of inaccurate detection and unstable detection. UTILITY MODEL CONTENTS

[0005] In view of the deficiencies in the above background art, the utility model provides a micro gas sensor, which solves the problem that the wavelength of the laser cannot be calibrated in real time in the prior art.

[0006] The utility model discloses a technical scheme is realized as follows: A micro gas sensor, including the casing, be equipped with temperature control assembly in the casing, be equipped with laser chip on temperature control assembly, be equipped with main road detector chip assembly and reference detector chip assembly in the casing, and laser chip is located between main road detector chip assembly and reference detector chip assembly or same side, realizes two kinds of structure layout. Reference gas chamber is equipped between reference detector chip assembly and laser chip, and the reference gas chamber is used to accommodate certain concentration standard target gas.

[0007] Preferably, the temperature control assembly includes a semiconductor refrigerating sheet fixed on the casing, a laser chip heat sink is arranged on the semiconductor refrigerating sheet, the laser chip is fixed on the laser chip heat sink, and a temperature sensor is arranged on the laser chip heat sink. Further, the temperature sensor is a thermistor.

[0008] Preferably, the main road detector chip assembly includes a main road detector chip heat sink fixed on the casing, and a main road detector chip is arranged on the main road detector chip heat sink.

[0009] Preferably, the reference detector chip assembly includes a reference detector chip heat sink fixed on the casing, and a reference detector chip is arranged on the reference detector chip heat sink. The main road detector chip, the reference detector chip and the laser chip are located in the same horizontal plane.

[0010] Preferably, the reference gas chamber is a transparent casing, a fixing seat is arranged on the casing, and the reference gas chamber is fixed on the fixing seat. The casing is arranged on a circuit control board, and an air inlet structure is arranged on the casing.

[0011] Preferably, the casing includes a casing seat fixedly connected with the circuit control board, a boss for bearing the temperature control assembly, the main road detector chip assembly and the reference detector chip assembly is arranged on the casing seat, and an upper cover is arranged on the casing seat.

[0012] Preferably, the air inlet structure includes a plurality of air holes arranged on the upper cover, and a waterproof air permeable film is arranged on the upper cover to cover the air holes.

[0013] The utility model discloses the beneficial effect:

[0014] By setting the shell to provide support for other components, setting the temperature control assembly, the temperature of the laser chip can be accurately controlled. Further by setting the reference gas chamber, the standard target gas of specified concentration can be contained, the laser emitted by the laser chip is used to irradiate the measured gas and the data is acquired by the main road detector chip assembly, the detection of the measured gas is realized; at the same time, the generated laser is irradiated on the reference detector chip assembly through the reference gas chamber to acquire the standard reference data, and the wavelength of the laser chip is calibrated in real time by using the standard reference data.

[0015] At the same time, the utility model discloses a micro - machining manufacturing process couples laser chip, main road detector chip assembly, reference detector chip assembly, reference gas chamber in a shell inside composition miniature gas sensor, utilizes the harmonic information of the combination reference gas chamber and reference detector chip assembly of semiconductor laser chip irradiation to realize the real -time calibration of wavelength and gas concentration detection, and the volume is small, and the process is simple, and it is beneficial to scale production. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the embodiment of the utility model, the drawings needed in the embodiment description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can also be obtained according to these drawings without creative labor for ordinary skilled in the art.

[0017] Figure 1 It is the cross-sectional structure schematic diagram of the state of the laser chip of the utility model between main road detector chip assembly and reference detector chip assembly.

[0018] Figure 2 It is the upper cover expansion structure schematic diagram of the utility model.

[0019] Figure 3 It is the structure schematic diagram of the state of the laser chip of the utility model on the same side of main road detector chip assembly and reference detector chip assembly.

[0020] In the drawing: 1: shell, 2: temperature control assembly, 3: laser chip, 4: main road detector chip assembly, 5: reference detector chip assembly, 6: reference gas chamber, 21: semiconductor refrigerating sheet, 22: laser chip heat sink, 23: temperature sensor, 41: main road detector chip heat sink, 42: main road detector chip, 51: reference detector chip heat sink, 52: reference detector chip, 61: fixed seat, 7: circuit control board, 8: air inlet structure, 11: shell seat, 12: boss, 13: upper cover, 14: air hole, 15: waterproof air permeable membrane. DETAILED DESCRIPTION

[0021] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0022] As shown in Figure 1 , 3 Embodiment 1, a miniature gas sensor, comprising a shell 1, which can provide support and installation base for other components. A temperature control assembly 2 is arranged in the shell 1, and a laser chip 3 is arranged on the temperature control assembly 2. The temperature control assembly can accurately control the temperature of the laser chip. A main path detector chip assembly 4 and a reference detector chip assembly 5 are arranged in the shell 1, and the laser chip 3 is located between or on the same side of the main path detector chip assembly 4 and the reference detector chip assembly 5, realizing two different structural layouts. A reference gas chamber 6 is arranged between the reference detector chip assembly 5 and the laser chip 3, and the reference gas chamber 6 is used to contain a certain concentration of standard target gas. When the laser chip is located on the same side of the main path detector chip assembly and the reference detector chip assembly, the light emitted by the laser chip directly irradiates onto the two assemblies. When the laser chip is located between the main path detector chip assembly and the reference detector chip assembly, the light emitted by the laser chip directly irradiates onto the main path detector chip, and the backlight of the laser chip irradiates onto the reference detector chip after passing through the reference gas chamber. By arranging the reference gas chamber, the specified concentration of standard target gas can be contained. The laser emitted by the laser chip irradiates the measured gas and the data is acquired by the main path detector chip assembly, realizing the detection of the measured gas. At the same time, the generated laser irradiates onto the reference detector chip assembly through the reference gas chamber to acquire standard reference data, and the wavelength of the laser chip is calibrated in real time by using the standard reference data.

[0023] In this embodiment, the laser chip, the main path detector chip assembly, the reference detector chip assembly and the reference gas chamber are coupled in a shell to form a miniature gas sensor by using microfabrication process. The wavelength is calibrated in real time and the gas concentration is detected by using the harmonic information of the semiconductor laser chip irradiation combined with the reference gas chamber and the reference detector chip assembly. The volume is small, the process is simple, and it is beneficial to large-scale production.

[0024] As a further specific embodiment, the reference gas chamber 6 is a transparent shell, and a fixing seat 61 is arranged on the shell 1, and the reference gas chamber 6 is fixedly arranged on the fixing seat 61. The transparent shell can be made of glass material to enable the light emitted by the laser chip to penetrate the reference gas chamber.

[0025] In this embodiment, the fixed seat is used to provide support and fixed base for the reference gas chamber, and the reference gas chamber is as close as possible to the laser chip and the reference detector chip assembly on both sides to reduce the influence of the target gas entering between the laser chip and the reference detector chip assembly.

[0026] In embodiment 2, on the basis of embodiment 1, the shell 1 is arranged on the circuit control panel 7, and the air inlet structure 8 is arranged on the shell 1. In this embodiment, the air inlet structure can diffuse the external target gas into the area between the laser chip and the main path detection chip assembly in the shell, and the corresponding parameters are obtained by the main path detection chip assembly under the irradiation of the laser of the specified wavelength emitted by the laser chip.

[0027] Specifically, the shell 1 includes a shell seat 11 fixedly connected with the circuit control panel 7, the shell seat 11 is provided with three bosses 12 for carrying the temperature control assembly 2, the main path detector chip assembly 4 and the reference detector chip assembly 5 respectively, and the shell seat 11 is provided with an upper cover 13. In this embodiment, the three bosses 12 are arranged, and the upper cover is fixed on the shell seat by bolts or adhesion, so as to encapsulate and protect the internal parts.

[0028] As a further optional implementation, a sealing ring is arranged between the upper cover and the shell seat to avoid water vapor leakage.

[0029] As a further real-time implementation, as shown in Figure 2 The air inlet structure 8 includes a plurality of air holes 14 opened in the upper cover 13, which facilitates the gas to enter and exit, and the upper cover 13 is provided with a waterproof and breathable film 15 for covering the air holes 14, so as to prevent dust and water vapor from entering the inside of the shell, affect the dry and clean environment of the internal parts, and avoid affecting the measurement accuracy for a long time.

[0030] In embodiment 3, on the basis of embodiment 2, the temperature control assembly 2 includes a semiconductor refrigeration piece 21 fixedly arranged on the shell 1, the semiconductor refrigeration piece 21 is provided with a laser chip heat sink 22, the laser chip 3 is fixedly arranged on the laser chip heat sink 22, and the laser chip heat sink 22 is provided with a temperature sensor 23. Specifically, in this embodiment, the laser chip heat sink 22 is used to transfer and diffuse the heat generated by the laser chip, and the temperature sensor 23 is a thermistor, which can sense the temperature of the laser chip heat sink in real time, so as to feedback and adjust the refrigeration capacity of the semiconductor refrigeration piece.

[0031] In the embodiment, the main path detector chip assembly 4 comprises a main path detector chip heat sink 41 fixed on the shell 1, and the main path detector chip 42 is arranged on the main path detector chip heat sink 41. The reference detector chip assembly 5 comprises a reference detector chip heat sink 51 fixed on the shell 1, and the reference detector chip 52 is arranged on the reference detector chip heat sink 51. The main path detector chip 42 and the reference detector chip are photoelectric sensing chips, and specifically, InGaAs photoelectric sensing chips can be adopted. The main path detector chip heat sink 41 and the reference detector chip heat sink 51 are respectively used for absorbing and diffusing the heat generated by the main path detector chip 42 and the reference detector chip 52, so as to avoid high temperature.

[0032] In addition, in the embodiment, in order to maintain that the laser emitted by the laser chip can better irradiate on the main path detector chip and the reference detector chip, the main path detector chip 42, the reference detector chip 52 and the laser chip 3 are located in the same horizontal plane.

[0033] As a further specific optional implementation manner, the circuit control board 7 is fixed on the back of the shell seat 11, and the circuit control board 7 mainly comprises input and output circuits, a laser driving circuit, a laser temperature control circuit, a microprocessor, and a transimpedance amplification filter circuit for the reference detector chip and the main path detector chip.

[0034] In actual use, the microprocessor of the circuit control board 7 controls the semiconductor refrigeration piece 21 to work through the laser temperature control circuit, so as to accurately control the temperature of the laser chip 3. At the same time, the laser chip 3 emits light containing the wavelength of the gas "fingerprint" absorption peak through the laser driving circuit, the light is irradiated on the main path detector chip 41 after being absorbed by the target gas entering the shell through the waterproof and air-permeable film 15 and the air-permeable hole 14 on the shell 1, and is converted into an electric signal through the transimpedance amplification filter circuit of the main path detector chip. The microprocessor extracts harmonic information through the lock-in amplification technology and calculates the gas concentration. The laser emitted by the semiconductor laser chip is irradiated on the reference detector chip through the reference gas chamber sealed with a certain concentration of target gas, and is converted into an electric signal through the transimpedance amplification filter circuit of the reference detector chip. The microprocessor extracts the harmonic information of the target gas in the reference gas chamber through the lock-in amplification technology to realize the wavelength calibration of the laser chip.

[0035] The microprocessor judges whether the position of the harmonic information is out of the set position range. If the position of the harmonic information is out of the set position range, the semiconductor refrigeration piece is controlled through the PID algorithm through the laser temperature control circuit, so as to adjust the temperature of the laser, so that the position of the harmonic information meets the requirement of the set position range, realizes the real-time calibration of the wavelength of the laser, and further improves the stability of the system.

[0036] The above merely describes preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A miniature gas sensor, characterized in that: The invention comprises a shell (1), wherein a temperature control component (2) is provided in the shell (1), and a laser chip (3) is provided on the temperature control component (2); a main detector chip component (4) and a reference detector chip component (5) are provided in the shell (1), and the laser chip (3) is located between the main detector chip component (4) and the reference detector chip component (5) or on the same side; and a reference gas chamber (6) is provided between the reference detector chip component (5) and the laser chip (3), and the reference gas chamber (6) is used to accommodate a standard target gas of a certain concentration.

2. The micro gas sensor according to claim 1, characterized in that: The temperature control component (2) comprises a semiconductor refrigeration plate (21) fixedly mounted on the housing (1), a laser chip heat sink (22) being provided on the semiconductor refrigeration plate (21), a laser chip (3) being fixedly mounted on the laser chip heat sink (22), and a temperature sensor (23) being provided on the laser chip heat sink (22).

3. The micro gas sensor according to claim 2, characterized in that: The temperature sensor (23) is a thermistor.

4. The micro gas sensor according to any one of claims 1 to 3, characterized in that: The main path detector chip assembly (4) comprises a main path detector chip heat sink (41) fixedly arranged on the housing (1), and a main path detector chip (42) is arranged on the main path detector chip heat sink (41).

5. The micro gas sensor according to claim 4, characterized in that: The reference detector chip assembly (5) comprises a reference detector chip heat sink (51) fixedly arranged on the housing (1), and a reference detector chip (52) is arranged on the reference detector chip heat sink (51).

6. The micro gas sensor according to claim 5, characterized in that: The main detector chip (42), the reference detector chip (52) and the laser chip (3) are located in the same horizontal plane.

7. The micro gas sensor according to claim 6, characterized in that: The reference air chamber (6) is a transparent shell, a fixing seat (61) is provided on the shell (1), and the reference air chamber (6) is fixed on the fixing seat (61).

8. The micro gas sensor according to any one of claims 1 to 3 and 5 to 7, characterized in that: The housing (1) is arranged on the circuit control board (7), and an air intake structure (8) is provided on the housing (1).

9. The micro gas sensor according to claim 8, characterized in that: The housing (1) comprises a housing base (11) fixedly connected to the circuit control board (7); the housing base (11) is provided with bosses (12) for respectively carrying the temperature control component (2), the main detector chip component (4), and the reference detector chip component (5); and the housing base (11) is provided with an upper cover (13).

10. The micro gas sensor according to claim 9, characterized in that: The air intake structure (8) comprises a plurality of air holes (14) provided on the upper cover (13), and a waterproof and breathable membrane (15) for covering the air holes (14) is provided on the upper cover (13).

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