A remote gas sensing system based on a lensless collimated laser

Abstract

This invention discloses a telemetry gas sensing system based on a lensless collimated laser, comprising a cylindrical optoelectronic transceiver assembly, a parabolic concave receiving mirror, a cylindrical shell, a laser driving and signal data processing unit, a data storage unit, and a wireless communication unit. The cylindrical optoelectronic transceiver assembly is fixed on the central axis inside 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. The beam emission end of the reflective collimated TO-can laser is aligned with the beam transmission end of the cylindrical shell. The parabolic concave receiving mirror is disposed at the other end inside the cylindrical shell, and the focal point of the parabolic concave receiving mirror coincides with the photosensitive surface of the TO-can detector. This invention utilizes a parabolic concave mirror instead of a traditional collimating lens. Since no optical lenses are used at either the transmitting or receiving end, it reduces both the complexity and weight of the system.

Description

Technical Field

[0001] This invention belongs to the field of laser gas concentration detection technology, and relates to gas concentration remote sensing technology in laser gas sensing, specifically to a remote gas sensing technology based on a reflection collimated laser. Background Technology

[0002] Tunable Semiconductor Laser Absorption Spectroscopy (TDLAS) is a trace gas detection technology based on spectrometry. It boasts advantages such as low susceptibility to environmental factors, short response time, high sensitivity, good selectivity, and applicability to various gases, making it an ideal method for detecting and monitoring gaseous pollutants. It is widely used in gas concentration detection applications. Remote gas sensors typically employ an open optical path gas detection method, suitable for various applications. Particularly in petroleum industry field gas concentration detection and hazardous gas leak monitoring applications, the safety of personnel and equipment is effectively ensured because both the detection personnel and the detection system are far from the gas being measured.

[0003] From an application perspective, field testing in the petroleum industry typically requires the simultaneous detection of multiple gases, including flammable and explosive gases (methane, ethane, propane, butane, acetylene, ethylene), toxic gases (hydrogen sulfide, carbon monoxide), and other gases (oxygen, water). However, when using gas absorption spectroscopy, different gases absorb at different wavelengths, necessitating the use of lasers with different wavelengths and corresponding collimating lenses. This not only increases the complexity of the multi-gas detection system but also increases its size, weight, and cost.

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

[0005] Meanwhile, from the perspective of technological development needs, with the widespread application of drone and robotic technologies, mounting gas concentration telemetry instruments on drones or robots can achieve remote telemetry in low-altitude areas or scenarios where it is not advisable for personnel to be present. This detection method can be widely applied to gas concentration monitoring and inspection in petroleum industrial sites, various factories, mining areas, urban residential areas, transportation hubs, gas pipelines, and natural environments. However, due to the limited payload of drones or robots, when integrating various high-precision remote gas sensors to complete high-precision atmospheric environmental monitoring, conventional laser multi-gas detection equipment is limited by factors such as large size, heavy weight, high cost, and system complexity.

[0006] Therefore, researching and developing small and lightweight telemetry gas sensors that are small in size, lightweight, have high detection accuracy, and are suitable for use on drones or robots has become a new technological challenge. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing laser gas detection or trace gas concentration measurement technologies, such as the influence of interference noise caused by reflection from the collimating lens surface of the laser on the detection sensitivity, high cost of remote sensing, monitoring or inspection of multiple gases, and the unfavorable size and weight of the measuring instruments for drones or robots. This invention proposes a remote gas sensing system based on a lensless collimating laser.

[0008] The technical solution proposed in this invention is:

[0009] A telemetry gas sensing system based on a lensless collimated laser includes a cylindrical photoelectric transceiver assembly, a gyroparabolic concave receiving mirror, a cylindrical shell with a bracket for fixing the cylindrical photoelectric transceiver assembly, a laser driving 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 provided at the beam transceiver end of the cylindrical shell to isolate possible external contamination and protect the various optical components 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 includes a reflective collimated TO-can laser and a TO-can detector without a focusing lens. The beam exit end of the reflective collimated TO-can laser is aligned with the beam transceiver end of the cylindrical shell. The gyroparabolic concave receiving mirror is located at the other end inside the cylindrical shell, and the focal point of the gyroparabolic concave receiving mirror 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 TO-can detector are arranged back-to-back at both ends inside the sleeve.

[0011] Furthermore, 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 connected to the detection unit of the reflective collimated TO-can laser and the TO-can detector, respectively, for tuning and controlling the laser and processing the signals 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 paraboloid collimating mirror. The emission point of the laser chip coincides with the focal point of the paraboloid collimating mirror. Simultaneously, the off-axis angle between the center line of the light cone emitted by the laser chip and the optical axis of the paraboloid collimating mirror is less than or equal to 90°. The conical beam emitted from the laser chip is reflected by the paraboloid collimating mirror to form a collimated laser beam. By adjusting the relative position of the emission point of the laser chip and the focal point of the paraboloid collimating mirror, the collimated laser beam can be made to form a slightly divergent beam at its far end. Depending on the application scenario, a parallel beam or a slightly divergent beam can be selected.

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

[0014] In a dual-wavelength reflective collimated TO-can laser, two laser COC chips of different wavelengths are arranged back-to-back at both ends of the upper part of the TEC. Two parabolic collimating mirrors are respectively arranged at both ends of the TEC. The laser emission ports of the laser COC chips are aligned with the focal points of the corresponding two parabolic collimating mirrors. At the same time, the off-axis angle between the center lines of the light cones emitted by the two laser COC chips and the optical axes of the corresponding parabolic collimating mirrors is less than or equal to 90°. When the light beams emitted by the two laser COC chips of different wavelengths are reflected by the two parabolic collimating mirrors, they will form two collimated beams parallel to the optical axes of the parabolic collimating mirrors.

[0015] In a four-wavelength reflective collimated TO-can laser, a collimating mirror with four paraboloids is positioned at the center of a specially designed heat sink. Four COC laser chips of different wavelengths are arranged in a cross shape around the four paraboloids in a face-to-face configuration. The output ports of the four COC laser chips are aligned with the focal points of the corresponding four paraboloids. Simultaneously, the off-axis angle between the center line of the light cone emitted by the four laser COC chips and the optical axis of the corresponding paraboloid is less than or equal to 90°. When the light beams emitted by the four different wavelength laser COC chips are reflected by the four paraboloids, four collimated beams parallel to the optical axes of the paraboloids are formed.

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

[0017] Specifically, the cycloidal concave receiving mirror is disposed inside the cylindrical shell, and its optical axis coincides with the central axis of the cylindrical shell; the focal point of the cycloidal concave receiving mirror coincides with the photosensitive surface of the TO-can detector, so that, except for the cross-section of the cylindrical photoelectric transceiver component, all incident light entering the cylindrical shell and parallel to the central axis of the cylindrical shell can be reflected by the cycloidal concave receiving mirror and converged on the photosensitive surface of the TO-can detector.

[0018] Specifically, the wireless communication unit is connected to both the data storage unit and the signal data processing unit, and is used to transmit 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 data information processed by the signal processing unit.

[0019] Furthermore, the telemetry gas sensing system also includes a red laser sight with ranging function. The red laser sight is disposed 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 detection reflection collimated TO-can laser, as well as to measure the distance from the telemetry gas sensing system to the reflective point.

[0020] Furthermore, the telemetry 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 disposed on the cylindrical outer shell, for displaying the data information detected and processed by the detection unit.

[0022] Furthermore, it also includes a handle, which is mounted on the cylindrical outer shell for handheld operation of the device; the handle is provided with a handle fixing buckle for fixing the telemetry gas sensing system to the gimbal bracket for use; the handle is provided with a rechargeable and replaceable portable rechargeable battery for powering the telemetry gas sensing system.

[0023] Furthermore, the telemetry gas sensing system also includes a beam reflecting unit of a pyramidal reflecting prism composed of three mutually perpendicular right-angled internal reflecting surfaces. This reflecting unit is placed at the far end of the optical path emitted by the collimated TO-can laser. The characteristic of this reflecting unit is that the incident light is reflected on the three right-angled internal reflecting surfaces and returns along the original path. The pyramidal shape is insensitive to the incident angle of the light, allowing the reflected beam to return to the beam emitter along a path parallel to the incident beam. In practical applications, the reflecting unit is placed at the far end of the laser's optical path to reflect the emitted laser back into the laser gas sensing system.

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

[0025] 1. This invention employs a reflective collimated laser as the light source. At the collimated beam emitting end, a gyroparabolic concave collimating mirror is used in the reflective collimated laser instead of a traditional collimating lens, effectively avoiding interference noise caused by reflection from the collimating lens surface, thereby significantly improving measurement accuracy. At the sensing beam receiving end, the focusing-free TO-can detector and the gyroparabolic concave receiving mirror are combined to focus the reflected laser beam absorbed by the gas being measured onto the detection unit of the TO-can detector. Since no optical lenses are used at either the emitting or receiving end, the complexity of the system is reduced, and the weight of the measurement system is also lightened.

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

[0027] 3. Parabolic concave reflectors are small in size and have high collimation efficiency. Therefore, several lasers of different wavelengths can be set in the same laser source at the same time, which is beneficial for multi-gas detection, improves detection efficiency, and enhances the versatility of the system.

[0028] 4. The reflected collimated TO-can laser and TO-can detector are designed back to back, making the cylindrical optoelectronic transceiver assembly compact and easy to install. This design can be applied to the detection of one gas or multiple gases.

[0029] 5. Since the surface of the reflector does not absorb the energy of the light beam, and the concave design can effectively reflect the light beam, this collimation structure is particularly suitable for high-power and ultra-high-power laser applications, avoiding the performance damage caused by thermal effects of traditional lenses; this invention can maintain stable optical performance and ensure the safe and efficient operation of the laser. Attached Figure Description

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

[0031] Figure 2 This 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 illustrating the principle of a collimated laser beam formed by reflecting a laser beam through a parabolic concave collimating mirror, as shown in Example 1.

[0033] Figure 4 This is a schematic diagram of Example 1, showing a parabolic collimating mirror and a specially designed heat sink mounted on a TO-can base.

[0034] Figure 5 This is a schematic diagram illustrating the principle of collimated laser beams formed by the reflection of two laser beams through a parabolic concave collimating mirror, as shown in Example 2.

[0035] Figure 6 This is a schematic diagram of Example 2, showing two parabolic collimating mirrors mounted on a TO-can base using a special heat sink.

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

[0037] Figure 8 This is a schematic diagram of the collimated laser beam formed by the reflection of four laser beams through four parabolic concave collimating mirrors in Example 3.

[0038] Figure 9 This is a top view of Example 3, showing the placement of four parabolic collimating mirrors on the TO-can base.

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

[0040] In the diagram: 10-Cylindrical photoelectric transceiver assembly, 11-Sleeve, 20-Gyrocopter concave receiving mirror, 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 laser sight, 80 Display screen;

[0041] 13 - Reflective collimating TO-can laser; 1311 / 1321 / 1331 - Rotary parabolic concave collimating mirror; 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 output port;

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

[0043] To facilitate understanding of the present invention, the technical solutions and advantages of the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Any mechanisms or methods not elaborated in this invention can be referred to in the prior art. The specific structures and features of the present invention are illustrated below by way of example and should not be construed as limiting the present invention in any way. Furthermore, any of the technical features mentioned below (including implicit or disclosed features), as well as any technical features directly shown or implied in the figures, can be arbitrarily combined or deleted among these technical features to form more other embodiments that may not be directly or indirectly mentioned in this invention. The accompanying drawings show preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0044] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0045] like Figure 1 and 2As shown, the telemetry gas sensing system based on a lensless collimated laser of the present invention includes a cylindrical optoelectronic transceiver assembly 10, a parabolic concave receiving mirror 20, a laser driving 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 laser sight 70, and a display screen 80. The cylindrical optoelectronic transceiver assembly 10, the parabolic concave receiving mirror 20, the laser driving and signal data processing unit 30, the data storage unit, and the wireless communication unit 40 are disposed within the cavity of the cylindrical shell 50, while the handle 60, the red laser sight 70, and the display screen 80 are disposed outside the cylindrical shell 50.

[0046] The cylindrical outer shell 50 has two ends along its central axis, one of which is a beam transceiver. A light-transmitting oblique window 51 is provided at the beam transceiver of the cylindrical outer shell 50 to isolate possible external contamination and protect the internal optical components. Inside the cylindrical outer shell 50, there is a bracket 52 for fixing the cylindrical optoelectronic transceiver assembly 10. The cylindrical optoelectronic transceiver assembly 10 is fixed on the central axis inside the cylindrical outer shell 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 back-to-back at both ends of the sleeve 11. The beam emission end of the reflective collimated TO-can laser 13 is aligned with the beam transmission and reception end of the cylindrical shell 50. The photosensitive surface of the TO-can detector 15 corresponds to the other end of the cylindrical shell 50. A PCB carrying a laser driver 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 driver 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 gyroparabolic concave receiving mirror 20 is located at the other end inside the cylindrical shell 50, and the focal point of the gyroparabolic concave receiving mirror 20 coincides with the photosensitive surface of the TO-can detector 15.

[0049] The data storage unit and wireless communication unit 40 are positioned behind the concave parabolic receiving mirror 20 to avoid interfering with light reception. The wireless communication unit is connected to both the data storage unit and the signal data processing unit 30, and is used to transmit data information detected by the detection unit.

[0050] The display screen 80 is located on the outer side of the beam transceiver end opposite to the cylindrical outer shell 50. The display screen 80 is equipped with a display unit for displaying the data information detected and processed by the detection unit.

[0051] The red laser sight 70 has a rangefinding function. The red laser sight 70 is located above the cylindrical shell 50. The red laser emitted by the red laser sight 70 is parallel to the gas detection collimated laser. It is used to indicate the direction and position of the laser emitted by the detection reflection collimated TO-can laser 13, as well as to measure the distance from the telemetry gas sensing system to the reflective point.

[0052] A handle 60 is mounted on the cylindrical outer shell 50 for handheld operation of the device. The handle 60 has a handle fixing buckle 61 for securing the telemetry gas sensing system to the gimbal bracket. A rechargeable and replaceable portable rechargeable battery 62 is housed within the handle 60 to power the telemetry gas sensing system.

[0053] When the remote gas sensing system of the present invention is working, a driving current with a sawtooth wave superimposed on a rectangular pulse wave drives a collimated TO-can laser 13. The laser emits a collimated laser beam that passes through the light-transmitting oblique window 51 and is directed towards the area to be detected. When the collimated laser beam passes through the space being detected and is reflected back by the reflecting unit or other reflecting surface, the energy of the laser beam at the spectral absorption peak of the gas changes accordingly due to the influence of the concentration of the gas being measured. The reflected laser beam absorbed by the gas being measured is converged by a parabolic concave receiving mirror 20 located inside the cylindrical shell 50 onto the detection unit of the TO-can detector 15. The detection unit converts the received laser signal into a corresponding electrical signal. A red laser aiming device 70 with a ranging function measures the distance between the reflection point and the remote gas sensing system of the present invention. After processing the wavelength tuning signal of the sawtooth wave, the average concentration of the gas being measured in the measurement optical path can be retrieved and displayed on the display screen 80. 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 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 The diagram illustrates the principle and setup method of a single-wavelength reflective collimated TO-can laser in Example 1.

[0057] Figure 3 This is a schematic diagram illustrating the working principle of a single-wavelength reflection-collimated laser. The reflection-collimated TO-can laser is a collimated laser beam 1312 formed by reflecting the diverging beam of the laser through a parabolic concave collimating mirror 1311. In the laser, the COC chip 1313 is mounted on the TEC 1314. The light output port 1317 of the laser COC chip 1313 is aligned with the focal point of the paraboloid collimating mirror 1311. At the same time, the off-axis angle between the center line of the light cone and the optical axis of the paraboloid collimating mirror 1311 is less than or equal to 90°. According to the principle of geometric optics, the diverging beam at the focal point of the concave mirror is reflected by the paraboloid collimating mirror 1311 to form a collimated beam 1312 parallel to the optical axis of the paraboloid collimating mirror 1311. Furthermore, by adjusting the relative position between the tip of the light cone emitted by the laser COC chip 1313 and the focal point of the paraboloid collimating mirror 1311, the collimated beam 1312 can be made to form a slightly divergent beam at the far end of the beam. For different application scenarios, a parallel beam or a beam with slight divergence can be selected.

[0058] Figure 4 The diagram shows a structure in which a parabolic collimating mirror 1311 and a special heat sink 1315 are mounted on a TO-can base 1316. A laser COC chip 1313 and a parabolic collimating mirror 1311 are mounted on a special heat sink 1315, which is mounted on a TEC 1314, which in turn is mounted on the TO-can base 1316. When the laser output port 1317 coincides with the focal point of the parabolic collimating mirror 1311, the beam emitted by the laser COC chip 1313 is reflected by the parabolic collimating mirror 1311 to form a reflected collimated beam 1312.

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

[0060] Example 2

[0061] The structures and working principles of Embodiment 2 and Embodiment 1 are basically the same. The difference lies in the structure of the cylindrical optoelectronic transceiver component in Embodiment 2, specifically the structure of the reflective collimated TO-can laser and the TO-can detector without a focusing lens are different.

[0062] like Figure 5-7 The above describes the principle and setup method of the dual-wavelength reflection collimated TO-can laser in this embodiment 2.

[0063] Figure 5 This is a schematic diagram illustrating the working principle of two collimated laser beams 1322 formed by the reflection of two laser beams by a rotating parabolic concave mirror 1321. In a dual-wavelength reflective collimated TO-can laser, two laser COC chips 1323 of different wavelengths are arranged back-to-back at both ends of the upper part of a TEC 1324. Two paraboloid collimating mirrors 1321 are respectively arranged at both ends of the TEC 1324. The laser output ports of the laser COC chips 1323 are aligned with the focal points of the corresponding two paraboloid collimating mirrors 1321. At the same time, the off-axis angle between the center line of the light cone emitted by the two laser COC chips 1323 and the optical axis of the corresponding paraboloid collimating mirror 1321 is less than or equal to 90°. After the diverging beams at the focal points of the two concave mirrors are reflected by the two paraboloid collimating mirrors 1321, two collimated beams 1322 parallel to the optical axis of the paraboloid collimating mirrors 1321 are formed. Furthermore, by adjusting the relative position of the tip of the light cone emitted by the laser COC chip 1323 and the focal point of the parabolic collimating mirror 1321, the collimated beam 1322 can be made to form a slightly divergent beam at the far end of the beam. For different application scenarios, a parallel beam or a beam with slight divergence can be selected.

[0064] Figure 6 This diagram illustrates the placement of two parabolic collimating mirrors 1321 on a TO-can base 1326 using a special heat sink 1325. Two laser COC chips 1323 are positioned back-to-back at both ends of the upper part of the special heat sink 1325. The two parabolic collimating mirrors 1321 are positioned at both ends of the lower part of the special heat sink 1325. The special heat sink 1325 is mounted on a TEC 1324, which in turn is mounted on the TO-can base 1326. When the output ports 1327 of the two lasers coincide with the focal points of their respective parabolic collimating mirrors 1321, the beams emitted by the two laser COC chips 1323 are reflected by the parabolic collimating mirrors 1321 to form two collimated beams 1322.

[0065] For a laser source corresponding to two collimated beams, detectors corresponding to two different wavelengths can be used.

[0066] Figure 7 This is a schematic diagram of photosensitive chips corresponding to two different wavelengths in a TO-can, as shown below. 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 a pad 1523, which is mounted on the TO-can base 1526. When the reflected laser beam absorbed by the gas being measured is converged onto the two photosensitive chips 1521 and 1522 by a parabolic concave receiving mirror 20 located inside the cylindrical shell 50, the two photosensitive chips 1521 and 1522 can convert the two different reflected lights into two sets of electrical signals respectively. It should be noted that the spectral response ranges of the two photosensitive chips 1521 and 1522 do not overlap, such as 1.653 μm for detecting methane and 4.6 μm for detecting carbon monoxide. Otherwise, a corresponding narrowband filter is required to separate the two wavelength signals.

[0067] Therefore, the telemetry gas sensing system of Example 2 can detect two different gases simultaneously, thus improving gas detection efficiency.

[0068] Example 3

[0069] The structure and working principle of Example 3 are basically the same as those of Example 1. The difference lies in the structure of the cylindrical optoelectronic transceiver component in Example 3, specifically the structure of the reflective collimated TO-can laser and the TO-can detector without a focusing lens are different.

[0070] like Figure 8-10 The diagram illustrates the principle and setup method of the four wavelengths of reflective collimated TO-can lasers in Example 3.

[0071] Figure 8This diagram illustrates a collimated laser beam 1332 formed by reflecting four laser beams through four parabolic concave collimating mirrors 1331. In a laser capable of emitting four wavelengths, the four parabolic concave collimating mirrors 1331 are positioned at the center of a specially designed heat sink 1325, and four different wavelength laser COC chips 1333 are arranged in a cross shape around the four parabolic concave collimating mirrors 1331 in a face-to-face configuration. The laser output ports 1337 of four different wavelength laser COC chips 1333 are aligned with the focal points of four corresponding paraboloid collimating mirrors 1331. Simultaneously, the off-axis angle between the center line of the light cone emitted by the four laser COC chips 1333 and the optical axis of the corresponding paraboloid collimating mirror 1331 is less than or equal to 90°. After the diverging beams at the focal points of the four concave mirrors are reflected by the four paraboloid collimating mirrors 1331, four collimated beams 1332 are formed, each parallel to the optical axis of the paraboloid collimating mirror 1331. Furthermore, by adjusting the relative position of the tip of the light cone emitted by the laser COC chip 1333 and the focal point of the paraboloid collimating mirror 1331, the collimated beams 1332 can be made to form slightly divergent beams at their far ends. Depending on the application scenario, either a parallel beam or a beam with slight divergence can be selected.

[0072] Figure 9 This is a top view of four paraboloid collimating mirrors 1331 mounted on a TO-can base 1336. The four paraboloid collimating mirrors 1331 are positioned at the center of a special heat sink 1335. Four laser COC chips 1333 of different wavelengths are arranged in pairs, facing each other, around the four paraboloid collimating mirrors 1331 in a symmetrical "+" shape. The special heat sink 1335 is mounted on a TEC 1334, which in turn is mounted on the TO-can base 1336. When the light output ports 1337 of the four different wavelength laser COC chips 1333 are aligned with the focal points of the four paraboloid collimating mirrors 1331, the beams emitted by the four laser COC chips 1333 are reflected by their respective paraboloid collimating mirrors 1331, forming four collimated beams 1332.

[0073] For a laser source corresponding to four collimated beams, conventional detectors corresponding to four different wavelengths can be used. For example... Figure 10As shown, in the TO-can, photosensitive chips 1531, 1532, 1533, and 1534, corresponding to four different wavelengths, are arranged side-by-side in the middle of a spacer 1535, which is mounted on the TO-can base 1536. When the reflected laser beam absorbed by the gas being measured is converged by a parabolic concave receiving mirror 20 located inside the cylindrical outer shell 50 onto the four photosensitive chips 1531, 1532, 1533, and 1534, the four photosensitive chips 1531, 1532, 1533, and 1534 can convert the reflected light of the four different wavelengths into four sets of electrical signals respectively. It should be noted that the spectral response ranges of the four photosensitive chips 1531, 1532, 1533, and 1534 need to be non-overlapping; otherwise, a corresponding narrowband filter is required to separate the four wavelength signals.

[0074] Therefore, the telemetry gas sensing system of Example 3 can simultaneously detect four different gases, further improving gas detection efficiency.

[0075] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, it will 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 appended claims and their equivalents.

Claims

1. A remote gas sensing system based on a lensless collimated laser, characterized in that, The device includes a cylindrical optoelectronic transceiver assembly, a parabolic concave receiving mirror, a cylindrical housing with a bracket for fixing the cylindrical optoelectronic transceiver assembly, a laser driving and signal data processing unit, a data storage unit, and a wireless communication unit; one end of the cylindrical housing is a beam transceiver end, and a light-transmitting oblique window is provided at the beam transceiver end of the cylindrical housing; the cylindrical optoelectronic transceiver assembly is fixed on the central axis inside the cylindrical housing, 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. The beam emission end of the reflective collimated TO-can laser is aligned with the beam transmission end of the cylindrical shell. The gyroparabolic concave receiving mirror is disposed at the other end inside the cylindrical shell, and the focal point of the gyroparabolic concave receiving mirror coincides with the photosensitive surface of the TO-can detector. The cylindrical optoelectronic transceiver assembly also includes a sleeve, and the reflective collimated TO-can laser and TO-can detector are arranged back-to-back at both ends inside the sleeve. The reflected collimated TO-can laser includes a laser chip of at least one wavelength and at least one paraboloid collimating mirror. The emission point of the laser chip coincides with the focal point of the paraboloid collimating mirror. Simultaneously, the off-axis angle between the center line of the light cone emitted by the laser chip and the optical axis of the paraboloid collimating mirror is less than or equal to 90°. The conical light beam emitted from the laser chip is reflected by the paraboloid collimating mirror to form a collimated laser beam. By adjusting the relative position of the emission point of the laser chip and the focal point of the paraboloid collimating mirror, the collimated laser beam can be made to form a slightly divergent beam at its far end. Depending on the application scenario, either a parallel beam or a beam with slight divergence can be selected. The reflected collimated TO-can laser has a single wavelength, or two, three, or four wavelengths; the chip of the reflected collimated TO-can laser is a COC, DFB, ICL, and / or QCL laser chip. The parabolic concave receiving mirror is disposed inside the cylindrical shell, and its optical axis coincides with the central axis of the cylindrical shell; and / or, the wireless communication unit is simultaneously connected to the data storage unit and the signal data processing unit for transmitting 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 data information processed by the signal processing unit.

2. The telemetry gas sensing system based on a lensless collimated laser as described in claim 1, 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 connected to the detection unit of the reflective collimated TO-can laser and the TO-can detector, respectively, for tuning and controlling the laser and processing the signals detected by the detection unit.

3. The telemetry gas sensing system based on a lensless collimated laser as described in claim 1, characterized in that, In a dual-wavelength reflective collimated TO-can laser, two laser COC chips of different wavelengths are arranged back-to-back at both ends of the upper part of the TEC. Two paraboloid collimating mirrors are respectively arranged at both ends of the TEC. The laser emission ports of the laser COC chips are aligned with the focal points of the corresponding two paraboloid collimating mirrors. At the same time, the off-axis angle between the center lines of the light cones emitted by the two laser COC chips and the optical axes of the corresponding paraboloid collimating mirrors is less than or equal to 90°. When the light beams emitted by the two laser COC chips of different wavelengths are reflected by the two paraboloid collimating mirrors, they will form two collimated beams parallel to the optical axes of the paraboloid collimating mirrors.

4. The telemetry gas sensing system based on a lensless collimated laser as described in claim 1, characterized in that, In a four-wavelength reflective collimated TO-CAN laser, four parabolic collimating mirrors are positioned at the center of a specially designed heat sink. Four laser COC chips of different wavelengths are arranged in a cross shape around the four parabolic collimating mirrors, facing each other. The emission ports of the four laser COC chips are aligned with the focal points of the corresponding four parabolic collimating mirrors. Simultaneously, the off-axis angle between the center lines of the light cones emitted by the four laser COC chips and the optical axes of the corresponding parabolic collimating mirrors is less than or equal to 90°. When the light beams emitted by the four laser COC chips are reflected by the four parabolic collimating mirrors, four collimated beams parallel to the optical axes of the parabolic collimating mirrors are formed.

5. The telemetry gas sensing system based on a lensless collimated laser as described in claim 4, characterized in that, When using TO-can lasers with multiple wavelengths of reflection collimation, the detection unit of the corresponding TO-can detector is also composed of multiple photosensitive chips of corresponding wavelengths, so as to complete the detection of different laser wavelengths respectively.

6. The telemetry gas sensing system based on a lensless collimated laser as described in any one of claims 1-5, characterized in that, It also includes a red laser sight with ranging function, which is disposed above the cylindrical outer shell. The red laser emitted by the red laser sight is parallel to the gas detection collimated laser, used to indicate the direction and position of the laser emitted by the detection collimated TO-can laser, and to measure the distance from the telemetry gas sensing system to the reflective point; and / or, It also includes a replaceable data storage unit and a wireless communication unit; and / or, It also includes a handle, which is mounted on the cylindrical outer shell for handheld operation of the device; the handle has a handle fixing buckle for fixing the telemetry gas sensing system to the gimbal bracket; the handle contains a rechargeable and replaceable portable rechargeable battery for powering the telemetry gas sensing system; and / or, It also includes a beam reflecting unit consisting of a pyramidal reflecting prism composed of three mutually perpendicular right-angled inner reflecting surfaces. This reflecting unit is placed at the far end of the optical path emitted by the collimated TO-can laser, and is used to reflect the laser emitted by the collimated TO-can laser back into the telemetry gas sensing system; and / or, It also includes a display unit, which is disposed on the cylindrical outer shell, for displaying the data information detected and processed by the detection unit.

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