Telemetering gas sensing system based on lensless collimation laser

Abstract

The invention discloses a telemetering gas sensing system based on a lensless collimation laser. The telemetering gas sensing system comprises a cylindrical photoelectric transceiving assembly, a convolute parabola concave receiving reflector, a cylindrical shell, a laser driving and signal data processing unit, a data storage unit and a wireless communication unit, the cylindrical photoelectric receiving and transmitting assembly is fixed on the central axis in the cylindrical shell, the cylindrical photoelectric receiving and transmitting assembly and the cylindrical shell are coaxial, the cylindrical photoelectric receiving and transmitting assembly comprises a reflection collimation TO-can laser and a TO-can detector without a focusing lens, and the light beam emitting end of the reflection collimation TO-can laser is consistent with the light beam receiving and transmitting end of the cylindrical shell in direction; the rotary parabola concave surface receiving reflector is arranged at the other end of the interior of the cylindrical shell, and the focus of the rotary parabola concave surface receiving reflector coincides with the photosensitive surface of the TO-can detector. The parabolic concave mirror is used for replacing a traditional collimating lens, and optical lenses are not adopted at the transmitting end and the receiving end, so that the complexity of the system is reduced, and the weight of the system is also reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of laser gas concentration detection, relates to a gas concentration remote sensing technology in laser gas sensing, and specifically relates to a remote sensing gas sensing technology based on a reflective collimated laser. Background Art

[0002] Tunable semiconductor laser absorption spectroscopy (TDLAS) is a trace gas detection technology based on spectroscopy. It has the advantages of being less affected by environmental factors, short response time, high sensitivity, good selectivity, and can be used for a variety of gas measurements. It is an ideal method for detecting and monitoring gas pollutants and is widely used in gas concentration detection applications. Remote sensing gas sensors usually use an open optical path gas detection method, which is suitable for a variety of applications. Especially in the field gas concentration detection and hazardous gas leak monitoring applications in the petroleum industry, since the detection personnel and the detection system are far away from the measured gas, the safety of personnel and equipment is effectively guaranteed.

[0003] From the application level, in the field detection of the petroleum industry, it is usually necessary to detect multiple gases at the same time, including the detection of flammable and explosive gases (methane, ethane, propane, butane, acetylene, ethylene), toxic gases (hydrogen sulfide, carbon monoxide) and other gases (oxygen, water). When using gas absorption spectrum detection, due to the different absorption wavelengths of different gases, the detection of different gases requires the use of lasers with different wavelengths and the use of different collimating lenses corresponding to these different wavelengths. This not only increases the complexity of the multi-gas detection system, but also increases the volume, weight and cost of the system.

[0004] From a technical perspective, when using tunable semiconductor laser absorption spectroscopy to detect gas, the laser wavelength needs to be modulated. Therefore, the interference noise generated by the reflected light on the surface of the collimating lens and the light beam of the laser resonant cavity will form background noise in the detector's detection signal. This interference noise changes with the ambient temperature. Therefore, detecting gas concentration at different ambient temperatures will result in different measurement results, which directly affects the measurement accuracy.

[0005] At the same time, from the perspective of scientific and technological development needs, with the widespread use of drone technology and robot technology, the gas concentration telemeter can be mounted on drones or robots to achieve remote telemetry in low-altitude areas or scenes where it is not suitable for staff to be present. This detection method can be widely used in gas concentration monitoring and inspection in scenes such as oil industry sites, various factory areas, various mining areas, urban residential areas, transportation hubs, gas pipelines, and natural environments. Due to the limited load of drones or robots, when it is necessary to integrate various high-precision telemetry gas sensors to complete high-precision atmospheric environment monitoring, conventional laser multi-gas detection equipment is limited by factors such as large size, heavy weight, high cost, and complex system.

[0006] Therefore, researching and developing small and lightweight telemetry gas sensors that are small in size, light in weight, have high detection accuracy, and are suitable for being carried by drones or robots has become a new technical challenge. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects in existing laser gas detection or trace gas concentration measurement technology, such as the detection sensitivity is affected by the interference noise caused by the reflection of the laser collimating lens surface, the cost of multiple gas remote sensing, monitoring or inspection is high, and the size and weight of the measuring instrument are not conducive to being carried by drones or robots. A remote sensing gas sensing system based on a lensless collimating laser is proposed.

[0008] The technical solution proposed by the present invention is:

[0009] A remote sensing gas sensing system based on a lensless collimated laser comprises a cylindrical photoelectric transceiver assembly, a cycloid concave receiving reflector, a cylindrical shell with a bracket for fixing the cylindrical photoelectric transceiver assembly, a laser drive and signal data processing unit, a data storage unit and a wireless communication unit; one end of the cylindrical shell is a beam transceiver end, and a light-transmitting oblique window is arranged at the beam transceiver end of the cylindrical shell to isolate possible external pollution and protect various optical elements inside; the cylindrical photoelectric transceiver assembly is fixed on the central axis inside the cylindrical shell and the two are coaxial; the cylindrical photoelectric transceiver assembly comprises a reflective collimated TO-can laser and a TO-can detector without a focusing lens, and the beam emitting end of the reflective collimated TO-can laser is in the same direction as the beam transceiver end of the cylindrical shell; the cycloid concave receiving reflector is arranged at the other end inside the cylindrical shell, and the focus of the cycloid concave receiving reflector coincides with the photosensitive surface of the TO-can detector.

[0010] Specifically, the cylindrical optoelectronic transceiver assembly further includes a sleeve, and the reflective collimated TO-can laser and the TO-can detector are arranged at two ends of the sleeve in a back-to-back manner.

[0011] Furthermore, a PCB carrying the laser driving and signal data processing unit is installed in the middle of the sleeve, and the laser driving and signal data processing unit is respectively connected to the detection unit of the reflective collimated TO-can laser and the TO-can detector, and is used to tune and control the laser and process the signal detected by the detection unit.

[0012] Specifically, the reflective collimated TO-can laser includes a laser chip of at least one wavelength and at least one rotating parabolic concave collimating reflector, the light emitting point of the laser chip coincides with the focus of the rotating parabolic concave collimating reflector, and at the same time, the off-axis angle between the center line of the light cone emitted by the laser chip and the optical axis of the rotating parabolic concave collimating reflector is less than or equal to 90°; the light cone light beam emitted from the laser chip is reflected by the rotating parabolic concave collimating reflector to form a collimated laser beam; by adjusting the relative position of the light emitting point of the laser chip and the focus of the rotating parabolic concave collimating reflector, the collimated laser beam can form a slightly divergent light beam at the far end of the light beam, and a parallel light beam or a slightly divergent light beam can be selected for different application scenarios.

[0013] Furthermore, the reflective collimated TO-can laser is a single wavelength, or two wavelengths, three wavelengths, or four wavelengths; the reflective collimated TO-can laser is a laser chip of DFB, ICL, and / or QCL.

[0014] In a dual-wavelength reflective collimation TO-can laser, two laser COC chips with different wavelengths are arranged at the two ends of the upper part of the TEC in a back-to-back manner, and the two rotating parabolic concave collimating reflectors are respectively arranged at the two ends of the TEC, and the laser light outlets of the laser COC chip are respectively aligned and overlapped with the focal points of the corresponding two rotating parabolic concave collimating reflectors. At the same time, the off-axis angles of the center lines of the light cones emitted by the two laser COC chips and the optical axes of the corresponding rotating parabolic concave collimating reflectors are less than or equal to 90°; when the light beams emitted by the two laser COC chips with different wavelengths are respectively reflected by the two rotating parabolic concave collimating reflectors, two collimated light beams parallel to the optical axes of the rotating parabolic concave collimating reflectors will be formed respectively.

[0015] Among them, in a four-wavelength reflective collimation TO-can laser, a laser having four rotating parabolic concave collimating reflectors is arranged at the center of a special heat sink, and four COC laser chips with different wavelengths are arranged face to face around the four rotating parabolic concave collimating reflectors in a cross-shaped distribution, and the light outlets of the four COC laser chips with different wavelengths are respectively aligned and overlapped with the focal points of the corresponding four rotating parabolic concave collimating reflectors, and at the same time, the off-axis angles of the center lines of the light cones emitted by the four laser COC chips and the optical axes of the corresponding rotating parabolic concave collimating reflectors are less than or equal to 90°; when the light beams emitted by the four laser COC chips with different wavelengths are respectively reflected by the four rotating parabolic concave collimating reflectors, four collimated light beams parallel to the optical axes of the rotating parabolic concave collimating reflectors are respectively formed.

[0016] Furthermore, when a reflective collimated TO-can laser of multiple wavelengths is used, the detection unit of the corresponding TO-can detector is also composed of multiple photosensitive chips of corresponding wavelengths, so as to respectively complete the detection of different laser wavelengths.

[0017] Specifically, the spiral parabola concave receiving reflector is arranged in the cylindrical shell, and its optical axis coincides with the central axis of the cylindrical shell; the focus of the spiral parabola concave receiving reflector coincides with the photosensitive surface of the TO-can detector, so that except for the cross-section of the cylindrical optoelectronic transceiver assembly, all incident light entering the cylindrical shell and parallel to the central axis of the cylindrical shell can be reflected by the spiral parabola concave receiving reflector and converged on the photosensitive surface of the TO-can detector.

[0018] Specifically, the wireless communication unit is connected to the data storage unit and the signal data processing unit at the same time, and is used to transmit the data information detected by the detection unit. The data storage unit and the wireless communication unit are respectively connected to the signal data processing unit, and are used to store and transmit the data information processed by the signal processing unit.

[0019] Furthermore, the remote sensing gas sensing system also includes a red light laser sight with a ranging function, which is arranged above the cylindrical shell. The red laser emitted by the red light laser sight is parallel to the gas detection collimated laser, and is used to indicate the direction and position of the laser emitted by the reflective collimated TO-can laser, and to measure the distance from the remote sensing gas sensing system to the reflecting point.

[0020] Furthermore, the remote sensing gas sensing system also includes a replaceable data storage unit and a wireless communication unit.

[0021] Furthermore, it also includes a display unit, which is arranged on the cylindrical shell and is used to display the data information detected and processed by the detection unit.

[0022] Furthermore, it also includes a handle, which is arranged on the cylindrical shell and is used for handheld operation of the device; the handle is provided with a handle fixing buckle, which is used to fix the remote sensing gas sensor system on the pan-tilt bracket for use; a rechargeable and replaceable mobile rechargeable battery is arranged in the handle, which is used to power the remote sensing gas sensor system.

[0023] Furthermore, the remote sensing gas sensing system also includes a beam reflection unit of a corner cone reflection prism composed of three mutually perpendicular right-angle internal reflection surfaces, and the reflection unit is placed at the far end of the optical path of the laser emitted by the reflective collimated TO-can laser. The characteristic of the reflection unit is that the incident light is reflected on the three right-angle internal reflection surfaces and returns along the original path. The corner cone is insensitive to the incident angle of the light, and the reflected light beam can return to the beam emission end in a path parallel to the incident light beam; in actual application scenarios, the reflection unit is placed at the far end of the optical path of the laser laser, and is used to reflect the laser emitted by the laser back to the laser gas sensing system.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] 1. The present invention adopts a reflective collimated laser as a light source. At the collimated light beam emitting end, a rotating parabolic concave collimating reflector is used in the reflective collimated laser to replace a traditional collimating lens, thereby effectively avoiding interference noise caused by reflection on the surface of the collimating lens, thereby significantly improving the measurement accuracy; at the sensing light beam receiving end, the focusing lens-free TO-can detector and the rotating parabolic concave receiving reflector are combined, and the reflected laser beam absorbed by the measured gas is converged by the rotating parabolic concave receiving reflector to the detection unit of the TO-can detector; since no optical lens is used at both the emitting end and the receiving end, not only the complexity of the system is reduced, but also the weight of the measurement system is reduced.

[0026] 2. Since the parabolic concave reflector can adapt to laser light sources of different wavelengths, this feature lays a physical foundation for full-spectrum gas detection.

[0027] 3. The parabolic concave reflector is small in size and has high collimation efficiency. Therefore, several lasers with different wavelengths can be set simultaneously in the same laser light source, which is conducive to the application in multi-gas detection, improves the detection efficiency, and enhances the versatility of the system.

[0028] 4. The reflective collimated TO-can laser and TO-can detector are designed back-to-back, so that the cylindrical optoelectronic transceiver assembly is compact and easy to install. This design can be applied to both single gas detection and multiple gas detection.

[0029] 5. Since the reflector surface does not absorb the beam energy and the concave design can effectively reflect the beam, the collimation structure is particularly suitable for the application of high-power and ultra-high-power lasers, avoiding the performance damage of traditional lenses due to thermal effects; the present invention can maintain stable optical performance and ensure the safe and efficient operation of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic structural diagram of the remote sensing gas sensing system based on lensless collimated laser of the present invention.

[0031] Figure 2 It is a side view and a three-dimensional schematic diagram of the cylindrical optoelectronic transceiver assembly of the present invention.

[0032] Figure 3 This is a schematic diagram of the principle of a collimated laser beam formed by a laser beam of Example 1 being reflected by a rotating parabolic concave collimating reflector.

[0033] Figure 4 This is a schematic diagram of setting a rotational parabolic concave collimating reflector and a special heat sink on a TO-can base in Example 1.

[0034] Figure 5 This is a schematic diagram of the principle of a collimated laser beam formed by two laser beams of Example 2 being reflected by a rotating parabolic concave collimating reflector.

[0035] Figure 6 This is a schematic diagram of Example 2 in which two rotational parabolic concave collimating mirrors are arranged on a TO-can base using a special heat sink.

[0036] Figure 7 This is a schematic diagram of the photosensitive chip corresponding to two different wavelengths in the TO-can of Example 2.

[0037] Figure 8 Schematic diagram of collimated laser beams formed by the four laser beams of Example 3 being reflected by four rotating parabolic concave collimating reflectors.

[0038] Fig. 9 This is a top view schematic diagram of setting four rotational parabolic concave collimating reflectors on the TO-can base in Example 3.

[0039] Fig.10 This is a schematic diagram of the photosensitive chips corresponding to four different wavelengths in the TO-can of Example 3.

[0040] In the figure: 10-cylindrical photoelectric transceiver assembly, 11-sleeve, 20-cycloidal parabola concave receiving reflector, 30-laser drive and signal data processing unit, 40-data storage unit and wireless communication unit, 50-cylindrical shell, 51-light-transmitting oblique window, 52-bracket, 60-handle, 61-handle fixing buckle 62-mobile rechargeable battery, 70-red light laser sight, 80 display screen;

[0041] 13-reflective collimated TO-can laser, 1311 / 1321 / 1331-rotating parabolic concave collimating reflector, 1312 / 1322 / 1332-collimated beam, 1313 / 1323 / 1333-laser COC chip, 1314 / 1324 / 1334-TEC, 1315 / 1325 / 1335-special heat sink, 1316 / 1326 / 1336-TO-can base, 1317 / 1327 / 1337-laser light outlet;

[0042] 15-TO-can detector, 1521 / 1522 / 1531 / 1532 / 1533 / 1534-photosensitive chip, 1525 / 1535-gasket, 1526 / 1536-TO-can base. DETAILED DESCRIPTION

[0043] In order to facilitate the understanding of the present invention, the technical solutions and advantages of the invention are further described in detail below in conjunction with the accompanying drawings and embodiments. The mechanisms or methods not described in the present invention can refer to the prior art. The specific structure and characteristics of the present invention are described below by way of example, which should not constitute any limitation to the present invention. At the same time, any of the technical features mentioned below (including implicit or disclosed), as well as any technical features directly displayed or implied in the figure, can continue to be arbitrarily combined or deleted between these technical features, so as to form more other embodiments that may not be directly or indirectly mentioned in the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly and comprehensively understood.

[0044] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0045] like Figure 1 and 2As shown, the telemetry gas sensing system based on lensless collimated laser of the present invention comprises a cylindrical photoelectric transceiver assembly 10, a cycloid parabola concave receiving reflector 20, a laser drive and signal data processing unit 30, a data storage unit and a wireless communication unit 40, a cylindrical shell 50, a handle 60, a red light laser sight 70 and a display screen 80. The cylindrical photoelectric transceiver assembly 10, the cycloid parabola concave receiving reflector 20, the laser drive and signal data processing unit 30, the data storage unit and the wireless communication unit 40 are arranged in the cavity of the cylindrical shell 50, and the handle 60, the red light laser sight 70 and the display screen 80 are arranged outside the cylindrical shell 50.

[0046] The cylindrical housing 50 has two ends in the direction of the central axis, one of which is a beam transceiver end. A light-transmitting oblique window 51 is provided at the beam transceiver end of the cylindrical housing 50 to isolate possible external pollution and protect various optical components inside. A bracket 52 for fixing the cylindrical optoelectronic transceiver assembly 10 is provided inside the cylindrical housing 50. The cylindrical optoelectronic transceiver assembly 10 is fixed on the central axis inside the cylindrical housing 50 and the two are coaxial.

[0047] The cylindrical optoelectronic transceiver assembly 10 includes a sleeve 11, a reflective collimated TO-can laser 13 and a TO-can detector 15 without a focusing lens. The reflective collimated TO-can laser 13 and the TO-can detector 15 are arranged at both ends of the sleeve 11 in a back-to-back manner. The beam emitting end of the reflective collimated TO-can laser 13 is in the same direction as the beam transceiver end of the cylindrical shell 50, and the photosensitive surface of the TO-can detector 15 corresponds to the other end of the cylindrical shell 50. The PCB carrying the laser driving and signal data processing unit 30 is installed in the middle of the sleeve 11, located between the reflective collimated TO-can laser 13 and the TO-can detector 15. The laser driving and signal data processing unit 30 is connected to the detection units of the reflective collimated TO-can laser 13 and the TO-can detector 15, respectively, for tuning and controlling the laser and processing the signals detected by the detection units.

[0048] The parabolic concave receiving reflector 20 is arranged at the other end inside the cylindrical shell 50 , and the focus of the parabolic concave receiving reflector 20 coincides with the photosensitive surface of the TO-can detector 15 .

[0049] The data storage unit and the wireless communication unit 40 are arranged behind the parabola concave receiving reflector 20 to avoid affecting the reception of light. The wireless communication unit is connected to the data storage unit and the signal data processing unit 30 at the same time to transmit the data information detected by the detection unit.

[0050] The display screen 80 is arranged on the outer side of the other end of the cylindrical housing 50 relative to the light beam transmitting and receiving end. The display screen 80 is provided with a display unit for displaying data information detected and processed by the detection unit.

[0051] The red light laser sight 70 has a ranging function and is disposed above the cylindrical housing 50. The red laser emitted by the red light laser sight 70 is parallel to the gas detection collimated laser and is used to indicate the direction and position of the laser emitted by the reflected collimated TO-can laser 13 and to measure the distance from the remote sensing gas sensing system to the reflecting point.

[0052] The handle 60 is arranged on the cylindrical shell 50 for handheld operation of the device. The handle 60 is provided with a handle fixing buckle 61 for fixing the remote gas sensing system on the pan / tilt bracket for use. A rechargeable and replaceable mobile rechargeable battery 62 is arranged in the handle 60 for powering the remote gas sensing system.

[0053] When the remote gas sensing system of the present invention is working, the driving current of the sawtooth wave superimposed on the rectangular pulse wave drives the reflective collimated TO-can laser 13, and the laser emits a collimated laser beam through the light-transmitting oblique window 51 to the area to be detected. When the collimated laser beam passes through the detected space and is reflected back by the reflection unit or other reflection surface, the laser beam is affected by the concentration of the gas to be measured, so that the energy of the laser beam at the spectral absorption peak of the gas changes accordingly. The reflected laser beam absorbed by the gas to be measured is converged to the detection unit of the TO-can detector 15 by the cyclotron parabola concave receiving reflector 20 arranged inside the cylindrical shell 50, and the detection unit converts the received laser signal into a corresponding electrical signal. The red laser sight 70 with a distance measurement function measures the distance between the reflection point position and the remote gas sensing system of the present invention, and then processes the wavelength tuning signal of the sawtooth wave to invert the average concentration of the gas to be measured in the measuring optical path and display it on the display screen 80, and the measured data is stored and transmitted through the data storage unit and the wireless communication unit 40.

[0054] Example 1

[0055] Based on the above structure and working principle, Example 1 is a remote sensing gas sensing system for detecting the concentration of a single gas. The following focuses on the structure and working principle of the cylindrical optoelectronic transceiver assembly 10 of Example 1, especially the structure and working principle of the reflective collimated TO-can laser 13 and the TO-can detector 15 without a focusing lens.

[0056] like Figure 3 and 4 As shown, the principle and setting method of the single wavelength reflective collimated TO-can laser in Example 1.

[0057] Figure 3 The working principle diagram of a single wavelength reflective collimated laser is shown in FIG. The reflective collimated TO-can laser is a collimated laser beam 1312 formed by reflecting the divergent beam of the laser through a rotating parabolic concave collimating reflector 1311 . In the laser, the COC chip 1313 is arranged on the TEC 1314, and the light outlet 1317 of the laser COC chip 1313 is aligned with the focus of the rotating parabolic concave collimating reflector 1311. At the same time, the off-axis angle between the center line of the light cone and the optical axis of the rotating parabolic concave collimating reflector 1311 is less than or equal to 90°; according to the principle of geometric optics, the divergent light beam at the focus of the concave reflector is reflected by the rotating parabolic concave collimating reflector 1311 to form a collimated light beam 1312 parallel to the optical axis of the rotating parabolic concave collimating reflector 1311. In addition, by adjusting the relative position of the top of the light cone emitted by the laser COC chip 1313 and the focus of the rotating parabolic concave collimating reflector 1311, the collimated light beam 1312 can be made to form a slightly divergent light beam at the far end of the light beam. For different application scenarios, a parallel light beam or a light beam with slight divergence can be selected.

[0058] Figure 4 The structure of a rotating parabolic concave collimating reflector 1311 and a special heat sink 1315 is shown. A laser COC chip 1313 and a rotating parabolic concave collimating reflector 1311 are arranged on a special heat sink 1315, and the special heat sink 1315 is arranged on a TEC 1314, and the TEC 1314 is arranged on the TO-can base 1316; when the laser light outlet 1317 coincides with the focus of the rotating parabolic concave collimating reflector 1311, the light beam emitted by the laser COC chip 1313 is reflected by the rotating parabolic concave collimating reflector 1311 to form a reflected collimated light beam 1312.

[0059] Corresponding to the laser light source of the collimated light beam of a single wavelength, a conventional detector of the corresponding wavelength can be used to convert the reflected light into an electrical signal to realize the detection of a single gas concentration.

[0060] Example 2

[0061] The structures and working principles of Example 2 and Example 1 are basically the same, the difference is that the structure of the cylindrical optoelectronic transceiver assembly of Example 2 is different, specifically, the structure of the reflective collimated TO-can laser and the TO-can detector without focusing lens is different.

[0062] like Figure 5-7 The above is the principle and setting method of the dual-wavelength reflective collimated TO-can laser of this embodiment 2.

[0063] Figure 5 Schematic diagram of the working principle of two collimated laser beams 1322 formed by two laser beams reflected by the rotating parabolic concave reflector 1321. In the dual-wavelength reflective collimated TO-can laser, two laser COC chips 1323 of different wavelengths are arranged at the two ends of the upper part of TEC 1324 in a "back-to-back" manner, and two rotating parabolic concave collimating reflectors 1321 are respectively arranged at the two ends of TEC 1324, and the laser light outlets of the laser COC chip 1323 are respectively aligned and overlapped with the focal points of the corresponding two rotating parabolic concave collimating reflectors 1321. At the same time, the off-axis angles of the center lines of the light cones emitted by the two laser COC chips 1323 and the optical axes of the corresponding rotating parabolic concave collimating reflectors 1321 are less than or equal to 90°; the divergent light beams at the focal points of the two concave reflectors are respectively reflected by the two rotating parabolic concave collimating reflectors 1321, and two collimated light beams 1322 parallel to the optical axes of the rotating parabolic concave collimating reflectors 1321 are respectively formed. In addition, by adjusting the relative position of the top of the light cone emitted by the laser COC chip 1323 and the focus of the rotating parabolic concave collimating reflector 1321, the collimated light beam 1322 can be made to form a slightly divergent light beam at the far end of the light beam. For different application scenarios, a parallel light beam or a slightly divergent light beam can be selected.

[0064] Figure 6 The schematic diagram is a diagram of setting two rotating parabolic concave collimating reflectors 1321 on a TO-can base 1326 using a special heat sink 1325. Two laser COC chips 1323 are respectively set at the two ends of the upper part of a special heat sink 1325 in a "back-to-back" manner, and two rotating parabolic concave collimating reflectors 1321 are respectively set at the two ends of the lower part of the special heat sink 1325. The special heat sink 1325 is set on a TEC 1324, and the TEC 1324 is set on the TO-can base 1326; when the light outlets 1327 of the two lasers coincide with the focal points of the corresponding rotating parabolic concave collimating reflectors 1321, the light beams emitted by the two laser COC chips 1323 are reflected by the rotating parabolic concave collimating reflectors 1321 to form two collimated light beams 1322.

[0065] Corresponding to the laser light source with two collimated light beams, detectors corresponding to two different wavelengths can be used.

[0066] Figure 7 The schematic diagram of the photosensitive chip corresponding to two different wavelengths in the TO-can is shown in FIG. Figure 7As shown, in the TO-can detector, two photosensitive chips 1521 and 1522 of different wavelengths are arranged side by side in the middle of the gasket 1523, and the gasket 1523 is arranged on the TO-can base 1526; when the reflected laser light beam absorbed by the measured gas is converged on the two photosensitive chips 1521 and 1522 by the spiral parabola concave receiving reflector 20 arranged in the cylindrical shell 50, the two photosensitive chips 1521 and 1522 can convert the two different reflected lights into two groups of electrical signals respectively. It should be noted that the spectral response ranges of the two photosensitive chips 1521 and 1522 do not overlap with each other, such as 1.653μm for detecting methane and 4.6μm for detecting carbon monoxide, otherwise it is necessary to use corresponding narrow-band filters to separate the two wavelength signals.

[0067] Therefore, the remote sensing gas sensing system of Example 2 can detect two different gases at the same time, thereby improving the gas detection efficiency.

[0068] Example 3

[0069] The structures and working principles of Example 3 and Example 1 are basically the same, the difference is that the structure of the cylindrical optoelectronic transceiver assembly of Example 3 is different, specifically, the structure of the reflective collimated TO-can laser and the TO-can detector without focusing lens is different.

[0070] like Figure 8-10 As shown, the principle and setting method of the reflective collimated TO-can laser of four wavelengths in Example 3.

[0071] Figure 8The schematic diagram is a collimated laser beam 1332 formed by four laser beams reflected by four rotating parabolic concave collimating reflectors 1331. In a laser capable of emitting four wavelengths, four rotating parabolic concave collimating reflectors 1331 are arranged at the center of a special heat sink 1325, and four laser COC chips 1333 of different wavelengths are arranged "face to face" around the four rotating parabolic concave collimating reflectors 1331, forming a "cross" shape. The laser light outlets 1337 of the four laser COC chips 1333 of different wavelengths are aligned and overlapped with the focal points of the corresponding four rotating parabolic concave collimating reflectors 1331. At the same time, the off-axis angles of the center lines of the light cones emitted by the four laser COC chips 1333 and the optical axes of the corresponding rotating parabolic concave collimating reflectors 1331 are less than or equal to 90°; the divergent light beams at the focal points of the four concave reflectors are respectively reflected by the four rotating parabolic concave collimating reflectors 1331, and four collimated light beams 1332 parallel to the optical axes of the rotating parabolic concave collimating reflectors 1331 are formed. In addition, by adjusting the relative position of the top of the light cone emitted by the laser COC chip 1333 and the focal point of the rotating parabolic concave collimating reflector 1331, the collimated light beam 1332 can be made to form a slightly divergent light beam at the far end of the light beam. For different application scenarios, a parallel light beam or a light beam with slight divergence can be selected.

[0072] Fig. 9 The schematic diagram of the top view of the four rotating parabolic concave collimating reflectors 1331 is set on the TO-can base 1336. The four rotating parabolic concave collimating reflectors 1331 are set at the center of the special heat sink 1335, and the four laser COC chips 1333 of different wavelengths are respectively set in the form of "face to face" around the four rotating parabolic concave collimating reflectors 1331, and are symmetrically distributed in a "cross" shape. The special heat sink 1335 is set on the TEC 1334, and the TEC 1334 is set on the TO-can base 1336; when the light outlets 1337 of the four laser COC chips 1333 of different wavelengths are respectively overlapped with the focus of the four rotating parabolic concave collimating reflectors 1331, the light beams emitted by the four laser COC chips 1333 are respectively reflected by the corresponding rotating parabolic concave collimating reflectors 1331 to form four collimated light beams 1332.

[0073] For a laser light source with four collimated beams, a conventional detector corresponding to four different wavelengths can be used. Fig.10As shown, in the TO-can, the photosensitive chips 1531, 1532, 1533 and 1534 corresponding to four different wavelengths are arranged side by side in the middle of the gasket 1535, and the gasket 1535 is arranged on the TO-can base 1536. When the reflected laser light beam absorbed by the measured gas is converged on the four photosensitive chips 1531, 1532, 1533 and 1534 by the cycloidal parabola concave receiving reflector 20 arranged in the cylindrical shell 50, the four photosensitive chips 1531, 1532, 1533 and 1534 can convert the reflected light of four different wavelengths into four groups of electrical signals respectively. It should be noted that the spectral response ranges of the four photosensitive chips 1531, 1532, 1533 and 1534 need not overlap each other, otherwise the corresponding narrow-band filters need to be used to separate the four wavelength signals.

[0074] Therefore, the remote sensing gas sensing system of Example 3 can detect four different gases at the same time, further improving the gas detection efficiency.

[0075] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. For ordinary technicians in this field, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A remote gas sensing system based on a lensless collimated laser, characterized in that: It comprises a cylindrical photoelectric transceiver assembly, a cycloidal parabola concave receiving reflector, a cylindrical shell with a bracket for fixing the cylindrical photoelectric transceiver assembly, a laser drive and signal data processing unit, a data storage unit and a wireless communication unit; one end of the cylindrical shell is a beam transceiver end, and a light-transmitting oblique window is arranged at the beam transceiver end of the cylindrical shell; the cylindrical photoelectric transceiver assembly is fixed on the central axis in the cylindrical shell and the two are coaxial; The cylindrical optoelectronic transceiver assembly includes a reflective collimated TO-can laser and a TO-can detector without a focusing lens, and the beam emitting end of the reflective collimated TO-can laser is in the same direction as the beam transmitting and receiving end of the cylindrical shell; the spiral parabola concave receiving reflector is arranged at the other end inside the cylindrical shell, and the focus of the spiral parabola concave receiving reflector coincides with the photosensitive surface of the TO-can detector.

2. The remote sensing gas sensing system based on lensless collimated laser as claimed in claim 1, characterized in that: The cylindrical optoelectronic transceiver assembly also includes a sleeve, and the reflective collimated TO-can laser and the TO-can detector are arranged at two ends of the sleeve in a back-to-back manner.

3. The remote sensing gas sensing system based on lensless collimated laser as claimed in claim 2, characterized in that: The PCB carrying the laser driving and signal data processing unit is installed in the middle of the sleeve. The laser driving and signal data processing unit is respectively connected to the detection unit of the reflective collimated TO-can laser and the TO-can detector, and is used to tune and control the laser and process the signal detected by the detection unit.

4. The remote sensing gas sensing system based on lensless collimated laser as claimed in claim 1, characterized in that: The reflective collimating TO-can laser comprises a laser chip of at least one wavelength and at least one rotating parabolic concave collimating reflector, the light emitting point of the laser chip coincides with the focus of the rotating parabolic concave collimating reflector, and at the same time, the off-axis angle between the center line of the light cone emitted by the laser chip and the optical axis of the rotating parabolic concave collimating reflector is less than or equal to 90°; the light cone-shaped light beam emitted from the laser chip is reflected by the rotating parabolic concave collimating reflector to form a collimated laser beam; by adjusting the relative position of the light emitting point of the laser chip and the focus of the rotating parabolic concave collimating reflector, the collimated laser beam can form a slightly divergent light beam at the far end of the light beam, and a parallel light beam or a slightly divergent light beam can be selected for different application scenarios.

5. The remote sensing gas sensing system based on lensless collimated laser as claimed in claim 4, characterized in that: The reflective collimated TO-can laser has a single wavelength, or has two wavelengths, three wavelengths, or four wavelengths; the reflective collimated TO-can laser is a laser chip of COC, DFB, ICL, and / or QCL.

6. The remote sensing gas sensing system based on lensless collimated laser as claimed in claim 4, characterized in that: In a dual-wavelength reflective collimation TO-can laser, two laser COC chips with different wavelengths are arranged at the two ends of the upper part of the TEC in a back-to-back manner, and the two rotating parabolic concave collimating reflectors are respectively arranged at the two ends of the TEC. The laser light outlets of the laser COC chip are respectively aligned and overlapped with the focal points of the corresponding two rotating parabolic concave collimating reflectors. At the same time, the off-axis angles of the center lines of the light cones emitted by the two laser COC chips and the optical axes of the corresponding rotating parabolic concave collimating reflectors are less than or equal to 90°; when the light beams emitted by the two laser COC chips with different wavelengths are respectively reflected by the two rotating parabolic concave collimating reflectors, two collimated light beams parallel to the optical axes of the rotating parabolic concave collimating reflectors will be formed respectively.

7. The remote sensing gas sensing system based on lensless collimated laser as claimed in claim 4, characterized in that: In a four-wavelength reflective collimating TO-can laser, a laser having four rotating parabolic concave collimating reflectors is arranged at the center of a special heat sink, and four COC laser chips of different wavelengths are arranged face to face around the four rotating parabolic concave collimating reflectors in a cross-shaped distribution. The light outlets of the four COC laser chips of different wavelengths are respectively aligned and overlapped with the focal points of the corresponding four rotating parabolic concave collimating reflectors. At the same time, the off-axis angles of the center lines of the light cones emitted by the four laser COC chips and the optical axes of the corresponding rotating parabolic concave collimating reflectors are less than or equal to 90°; when the light beams emitted by the four laser COC chips of different wavelengths are respectively reflected by the four rotating parabolic concave collimating reflectors, four collimated light beams parallel to the optical axes of the rotating parabolic concave collimating reflectors are formed.

8. The remote sensing gas sensing system based on lensless collimated laser as claimed in claim 4, characterized in that: When a reflective collimated TO-can laser of multiple wavelengths is used, the detection unit of the corresponding TO-can detector is also composed of multiple photosensitive chips of corresponding wavelengths, so as to respectively complete the detection of different laser wavelengths.

9. The remote sensing gas sensing system based on lensless collimated laser according to any one of claims 1 to 8, characterized in that: The parabolic concave receiving reflector is arranged in the cylindrical shell, and its optical axis coincides with the central axis of the cylindrical shell; and / or the wireless communication unit is connected to the data storage unit and the signal data processing unit at the same time, for transmitting the data information detected by the detection unit; the data storage unit and the wireless communication unit are respectively connected to the signal data processing unit, for storing and transmitting the data information processed by the signal processing unit.

10. The remote sensing gas sensing system based on lensless collimated laser according to any one of claims 1 to 8, characterized in that: It also includes a red laser sight with a distance measurement function, which is arranged above the cylindrical shell. The red laser emitted by the red laser sight is parallel to the gas detection collimated laser, and is used to indicate the direction and position of the laser emitted by the reflective collimated TO-can laser, and to measure the distance from the remote sensing gas sensing system to the reflective point; and / or, Also includes a replaceable data storage unit and a wireless communication unit; and / or, It also includes a handle, which is arranged on the cylindrical shell and is used for handheld operation of the device; the handle is provided with a handle fixing buckle, which is used to fix the remote gas sensing system on the pan / tilt bracket for use; a rechargeable and replaceable mobile rechargeable battery is arranged in the handle, which is used to power the remote gas sensing system; and / or, It also includes a light beam reflection unit of a corner cone reflection prism composed of three mutually perpendicular right-angle internal reflection surfaces, the reflection unit is placed at the far end of the light path of the laser emitted by the reflective collimated TO-can laser, and is used to reflect the laser emitted by the reflective collimated TO-can laser back to the remote sensing gas sensing system; and / or, It also includes a display unit, which is arranged on the cylindrical shell and is used to display the data information detected and processed by the detection unit.

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