Laser emitter with built-in reference light path and laser gas detection device
By integrating a reference optical path inside the laser emitter, the problem of optical path interference that cannot be solved by an external reference channel is solved. This enables the miniaturization of laser gas detection equipment and precise optical path anomaly positioning, thereby improving detection accuracy and reducing false alarm rate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HENAN HANWEI ELECTRONICS
- Filing Date
- 2025-04-09
- Publication Date
- 2026-05-29
AI Technical Summary
In existing laser gas detection equipment, external reference channels and standard gas chambers cannot solve the problem of interference from foreign objects in the optical path, and cannot distinguish the cause of photoelectric signal attenuation, resulting in false alarms and increased costs.
By integrating a reference optical path inside the laser emitter, and comparing the built-in reference optical path signal with the detection optical path signal through a reference photodetector and a beam splitter, the cause of light intensity attenuation can be determined, thus achieving miniaturization and precise location of the problem.
It achieves immunity to interference from foreign objects in the optical path, reduces false alarms, improves detection accuracy and equipment miniaturization, and reduces system analysis costs.
Smart Images
Figure CN224303539U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of semiconductor laser gas detection technology, specifically to a laser emitter with a built-in reference optical path and a laser gas detection device. Background Technology
[0002] Laser gas detection equipment based on TDLAS technology uses narrowband lasers as a light source and performs quantitative and qualitative analysis of gaseous components in the air according to Beer-Lambert's law. Due to its advantages such as high sensitivity, strong anti-interference capability, high detection accuracy, wide detection range, and long lifespan, related products are widely used in home, commercial, and industrial fields. However, during use, substances in the environment where the laser gas detection equipment operates, such as dust, oil fumes, and water vapor, may interfere with the optical path and light intensity, resulting in false alarms, inaccurate detection data, and other abnormalities.
[0003] To mitigate the negative impacts of environmental factors, various research and development units have developed gas detection solutions and equipment with features such as heating, reference channels, and standard gas chambers. However, both the reference channel and the reference gas chamber are located externally to the laser source. When foreign objects adhere to the laser source, causing light intensity attenuation, this existing solution cannot address the problem. Furthermore, external reference channels and standard gas chambers occupy a significant amount of space, failing to meet the demands for miniaturization, simplification, and high integration in product design.
[0004] Besides setting up reference channels and standard gas chambers, another approach is to establish a data model and set thresholds through extensive testing in the early stages. During use, if the signal received by the photodetector falls below the threshold, it is interpreted as dirt or obstruction of the optical path, resulting in an abnormal signal output or a warning signal. However, this approach also has drawbacks: the laser's emission power and intensity may decrease over time due to factors such as power supply noise. The control module cannot distinguish between a photodetector signal falling below the set threshold caused by this and one caused by obstruction, leading to an inability to accurately pinpoint the problem and increasing costs during the problem analysis phase.
[0005] To address these issues, people have been seeking a better technological solution. Summary of the Invention
[0006] To address the problems existing in the prior art, this utility model proposes a laser emitter with a built-in reference optical path, in which the reference optical path is integrated into the laser emitter. This utility model also proposes a laser gas detection device.
[0007] The technical solution adopted in this utility model is:
[0008] In a first aspect, the present invention provides a laser emitter with a built-in reference optical path, comprising: a housing, and a reference photodetector, a beam splitter and a laser source disposed inside the housing;
[0009] The upper part of the housing is provided with a light window for transmitting detection laser light;
[0010] The laser source is configured corresponding to the optical window and is used to emit a detection laser and transmit it through the optical window.
[0011] The beam splitting component is used to split the detection laser emitted from the laser source into a reference detection laser and irradiate it onto the reference photodetector.
[0012] The reference photodetector is configured corresponding to the beam splitter and is used to receive the reference detection laser and output a reference electrical signal.
[0013] Based on the above, the laser source is disposed at the bottom of the housing, and the reference photodetector is disposed on the side wall of the housing;
[0014] The beam splitter includes a beam splitter disposed in the detection laser optical path emitted from the laser source;
[0015] The detection laser emitted by the laser source is transmitted through the optical window, and the beam splitter separates the detection laser into a reference detection laser, which then illuminates the reference photodetector.
[0016] Based on the above, both the laser source and the reference photodetector are disposed at the bottom of the housing;
[0017] The beam splitter includes a reflector and a beam splitter disposed in the detection laser optical path emitted from the laser source;
[0018] The detection laser emitted by the laser source is transmitted through the optical window, and the beam splitter splits the detection laser into a reference detection laser. The split reference detection laser is reflected by the mirror and then illuminates the reference photodetector.
[0019] Based on the above, the beam splitter is a semi-transparent and semi-reflective mirror.
[0020] Based on the above, the housing is designed as a sealed cavity and has an injection port, through which inert gas is injected into the sealed cavity.
[0021] Based on the above, the housing includes a cap and a base; the cap and the base are sealed together to form a sealed cavity, and the sealed cavity is filled with an inert gas; the base is provided with pins for electrical connection with an external circuit.
[0022] Based on the above, the housing adopts TO packaging.
[0023] Based on the above, the inner wall of the tube cap is designed with a slot or a raised step for placing the beam splitter.
[0024] Secondly, this utility model provides a laser gas detection device, including a laser emitter, a main detector, and a control circuit module. The laser emitter and the main detector are electrically connected to the control circuit module, wherein the laser emitter is a laser emitter with a built-in reference optical path.
[0025] The detection laser emitted by the laser emitter with the built-in reference optical path passes through the detection gas chamber and is received by the main detector and converted into a detection electrical signal; this detection electrical signal is transmitted to the control circuit module for analysis and processing to obtain the gas concentration;
[0026] The reference detection laser beam split by the beam splitting component is received by the reference photodetector and converted into a reference electrical signal. This reference electrical signal is then transmitted to the control circuit module for analysis and processing, and is used as a reference optical path signal for detecting optical path anomalies and system calibration.
[0027] Based on the above, the housing is equipped with a temperature sensor for collecting the internal temperature of the laser emitter and a temperature control chip for controlling the internal temperature of the laser emitter.
[0028] This utility model has substantial features and advancements compared to the prior art, specifically:
[0029] This invention relates to a laser emitter with a built-in reference optical path. By sealing a reference photodetector inside the laser emitter, the output reference signal is unaffected by external environmental influences and interference. Furthermore, the reference photodetector and the tunable light source are integrated within the laser emitter, eliminating the need for a separate reference signal cavity, saving space, and facilitating the high integration and miniaturization of gas detection solutions and equipment.
[0030] The detection beam and the reference beam of the laser emitter with the built-in reference optical path of this invention originate from the same beam of light emitted by the tunable light source. Therefore, the comparison result between the reference electrical signal and the detection signal does not include the light intensity attenuation error caused by the lifespan of the tunable light source.
[0031] The laser gas detection device of this invention can determine whether the light intensity attenuation is caused by foreign objects blocking the optical path or the power attenuation due to the lifespan of the laser transmitter by comparing the photoelectric signal collected by the reference optical path inside the laser transmitter with the photoelectric signal received by the main detector outside the laser transmitter through the control circuit module. This allows for timely and accurate location of the problem. Attached Figure Description
[0032] Figure 1 This is a schematic diagram of the laser emitter with a built-in reference optical path in Examples 1 and 2.
[0033] Figure 2 This is a schematic diagram of the laser emitter with a built-in reference optical path in Example 3.
[0034] Figure 3 This is a schematic diagram of the laser gas detection device in Example 3.
[0035] In the diagram: 1. Housing; 2. Reference photodetector; 3. Beam splitter; 31. Beam splitter; 32. Reflector; 4. Laser source; 41. Detection laser; 42. Reference detection laser; 5. Optical window; 6. Tube cap; 7. Base; 8. Tube foot; 9. Gas injection port. Detailed Implementation
[0036] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. Example 1
[0037] This embodiment provides a laser emitter with a built-in reference optical path, such as... Figure 1 As shown in the figure, the lines with arrows represent the optical path, including: housing 1, and reference photodetector 2, beam splitting component 3 and laser source 4 disposed inside the housing 1;
[0038] The upper part of the housing 1 is provided with a light window 5 for transmitting detection laser;
[0039] The laser source 4 is configured corresponding to the optical window 5 and is used to emit a detection laser 41 which is transmitted out through the optical window 5.
[0040] The beam splitting component 3 is used to split the detection laser 41 emitted from the laser source 4 into a reference detection laser 42 and irradiate it onto the reference photodetector 2.
[0041] The reference photodetector 2 is configured corresponding to the beam splitter and is used to receive the reference detection laser and output a reference electrical signal.
[0042] Those skilled in the art will understand that the reference electrical signal output by the reference photodetector can be acquired by a microprocessor after being processed by a filtering and amplification circuit.
[0043] Those skilled in the art will understand that when the laser emitter with the built-in reference optical path of this embodiment is used in a gas detection device, the reference detection laser emitted from the laser emitter does not pass through the gas to be tested, so the reference electrical signal output by the reference photodetector remains at a stable value. The detection laser transmitted from the optical window passes through the gas to be tested and then enters the main detector of the gas detection device, generating a detection photoelectric signal. The control circuit module of the gas detection device will collect, amplify, and compare the detection photoelectric signal output by the main detector and the reference electrical signal output by the reference photodetector. The specific comparison and judgment logic between the detection photoelectric signal and the reference electrical signal is as follows:
[0044] The laser light source 4 emits a laser wavelength range that covers the gas absorption peak. Since its structure and optical path remain largely unchanged during use after being fixed, there is a fixed difference ΔV0 = V between the reference photoelectric signal and the detection photoelectric signal within the laser wavelength range. 参0 -V 检0 ;
[0045] When the optical path or window is clean and there is no gas to be measured in the air, the difference between the reference photoelectric signal and the detection photoelectric signal ΔV = V across the entire range of laser wavelength scanning. 参 -V 检 =ΔV0;
[0046] When the target gas is present in the detection optical path, the optical signal received by the main detector has an absorption pit compared to the optical signal received by the reference photodetector. The difference between the reference photoelectric signal and the detection photoelectric signal in the wavelength range outside the absorption pit is ΔV = V. 参 -V 检 =ΔV0, the size of the absorption pit has a linear relationship with the gas concentration. The control circuit module integrates the area of the absorption pit, amplifies it, and then outputs the concentration or alarm signal ΔV. 气体吸收 =ΔV-ΔV0=V 参 -V 检 -ΔV0;
[0047] When the optical path or window is blocked by a foreign object, causing light intensity attenuation, the difference between the reference photoelectric signal and the detection photoelectric signal ΔV=V across the entire range of laser wavelength scanning. 参 -V 检 >ΔV0, at this time the control circuit module can drive the audible and visual alarm module to perform abnormal prompts and maintenance;
[0048] Furthermore, when light intensity fluctuates due to factors such as temperature, light source control voltage, and lifespan, the reference photoelectric signal V... 参 <V 参0 And detect photoelectric signal V 检 <V 检0At this point, the control circuit module will calibrate and compensate the system. The specific methods for calibration and compensation can be determined by the system's preset calibration and compensation schemes, and are not within the scope of this solution.
[0049] In some exemplary embodiments, the laser source is selected as a tunable source, which emits laser light with excellent monochromaticity and outputs a narrow and adjustable laser wavelength range.
[0050] In some exemplary embodiments, to meet the requirements of miniaturization, the housing adopts a TO package, including a cap 6 and a base 7; the cap 6 and the base 7 are sealed together to form a sealed cavity, and the sealed cavity is filled with an inert gas; the base 7 is provided with pins 8 for electrical connection with external circuitry. A light window 5 is fixed to the top of the cap 6, covering all or part of the top space of the cap 6, and the connection point is sealed and airtight.
[0051] Furthermore, the inner wall of the cap 6 is preferably designed with a slot or raised step at the center to fix the beam splitting component 3. The position and angle must meet the optical path requirements of the detection laser 41 and the reference detection laser 42.
[0052] Furthermore, the sealing connection method between the cap 6 and the base 7 is preferably, but not limited to, welding, gluing, etc.
[0053] In some exemplary embodiments, the housing 1 is designed as a sealed cavity and filled with inert gas. The inert gas filling method involves injecting gas through a gas injection port 9 on the housing 1 and then sealing the port 9; wherein, when the housing 1 is TO-packaged, the gas injection port 9 can be located on the cap 6 or the base 7. Alternatively, the inert gas filling method can be performed by sealing the cap 6 and the base 7 in an environment filled with inert gas. Example 2
[0054] The difference between this embodiment and Embodiment 1 is that this embodiment provides a specific reference optical path.
[0055] like Figure 1 As shown, the laser source 4 is disposed at the bottom of the housing 1, and the reference photodetector 2 is disposed on the side wall of the housing 1;
[0056] The beam splitter 3 includes a beam splitter 31 disposed in the detection laser optical path emitted from the laser source;
[0057] The detection laser 41 emitted by the laser source 4 is transmitted through the optical window 5, and the beam splitter 31 splits the detection laser into a reference detection laser 42, which then illuminates the reference photodetector 2. Example 3
[0058] The difference between this embodiment and Embodiment 1 is that this embodiment provides a reference optical path that can reduce the space occupied to a certain extent.
[0059] like Figure 2 As shown, both the laser light source 4 and the reference photodetector 2 are disposed at the bottom of the housing 1;
[0060] The beam splitter 3 includes a reflector 32 and a beam splitter 31 disposed in the optical path of the detection laser 41 emitted from the laser source 4;
[0061] The detection laser 41 emitted by the laser source 4 is transmitted through the optical window 5. The beam splitter 31 splits the detection laser 41 into a reference detection laser 42. The split reference detection laser 42 is reflected by the reflector 32 and then illuminates the reference photodetector 2.
[0062] In some exemplary embodiments, the transmission and reflectivity range of the beam splitter 31 can be customized as needed, and a semi-transparent and semi-reflective mirror with a specific reflective film deposited on the optical glass can be selected, preferably with a 1:1 ratio of transmitted light energy to reflected light energy.
[0063] In some exemplary embodiments, the reflector is preferably a total reflection lens. Example 4
[0064] This embodiment provides a laser gas detection device, such as... Figure 3 As shown, it includes a laser emitter, a main detector, and a control circuit module. The laser emitter and the main detector are electrically connected to the control circuit module. The laser emitter is the laser emitter with a built-in reference optical path as described in any one of Embodiments 1-3.
[0065] The detection laser emitted by the laser emitter with the built-in reference optical path passes through the detection gas chamber and is received by the main detector and converted into a detection electrical signal; this detection electrical signal is transmitted to the control circuit module for analysis and processing to obtain the gas concentration;
[0066] The reference detection laser beam split by the beam splitting component is received by the reference photodetector and converted into a reference electrical signal. This reference electrical signal is transmitted to the control circuit module for analysis and processing, and then used as a reference optical path signal to detect optical path anomalies (foreign objects blocking the optical path or window) and for system calibration.
[0067] In some exemplary embodiments, the laser gas detection device further includes an audible and visual alarm module for providing audible and visual alarm prompts when an optical path abnormality is detected or when system calibration is required.
[0068] It should be noted that those skilled in the art should understand how the reference optical path signal is used to achieve optical path anomaly detection and system calibration. For example, if the reference detection laser emitted from the laser emitter does not pass through the gas to be tested, the reference electrical signal output by the reference photodetector remains at a stable value. The detection laser transmitted from the optical window passes through the gas to be tested and then enters the main detector of the gas detection device, generating a detection photoelectric signal. The control circuit module will collect, amplify, and compare the detection photoelectric signal output by the main detector and the reference electrical signal output by the reference photodetector. The specific comparison and judgment logic between the detection photoelectric signal and the reference electrical signal is as follows:
[0069] The laser light source 4 emits a laser wavelength range that covers the gas absorption peak. Since its structure and optical path remain largely unchanged during use after being fixed, there is a fixed difference ΔV0 = V between the reference photoelectric signal and the detection photoelectric signal within the laser wavelength range. 参0 -V 检0 ;
[0070] When the optical path or window is clean and there is no gas to be measured in the air, the difference between the reference photoelectric signal and the detection photoelectric signal ΔV = V across the entire range of laser wavelength scanning. 参 -V 检 =ΔV0;
[0071] When the target gas is present in the detection optical path, the optical signal received by the main detector has an absorption pit compared to the optical signal received by the reference photodetector. The difference between the reference photoelectric signal and the detection photoelectric signal in the wavelength range outside the absorption pit is ΔV = V. 参 -V 检 =ΔV0, the size of the absorption pit has a linear relationship with the gas concentration. The control circuit module integrates the area of the absorption pit, amplifies it, and then outputs the concentration or alarm signal ΔV. 气体吸收 =ΔV-ΔV0=V 参 -V 检 -ΔV0;
[0072] When the optical path or window is blocked by a foreign object, causing light intensity attenuation, the difference between the reference photoelectric signal and the detection photoelectric signal ΔV=V across the entire range of laser wavelength scanning. 参 -V 检 >ΔV0, at this time the control circuit module can drive the audible and visual alarm module to perform abnormal prompts and maintenance;
[0073] Furthermore, when light intensity fluctuates due to factors such as temperature, light source control voltage, and lifespan, the reference photoelectric signal V... 参 <V 参0 And detect photoelectric signal V 检 <V 检0At this point, the control circuit module will calibrate and compensate the system. The specific methods for calibration and compensation can be determined by the system's preset calibration and compensation schemes, and are not within the scope of this solution.
[0074] In some exemplary embodiments, since the tunable light source is easily affected by temperature, a temperature sensor for collecting the internal temperature of the laser emitter and a temperature control chip for controlling the internal temperature of the laser emitter can also be designed in the spare position outside the tunable light source 4 and the reference photodetector 2 as needed. These are connected to the control circuit module through pins on the outside of the base.
[0075] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.
Claims
1. A laser emitter with a built-in reference optical path, characterized in that, Includes: a housing, and a reference photodetector, a beam splitter, and a laser source disposed inside the housing; The upper part of the housing is provided with a light window for transmitting detection laser light; The laser source is configured corresponding to the optical window and is used to emit a detection laser and transmit it through the optical window. The beam splitting component is used to split the detection laser emitted from the laser source into a reference detection laser and irradiate it onto the reference photodetector. The reference photodetector is configured corresponding to the beam splitter and is used to receive the reference detection laser and output a reference electrical signal.
2. The laser emitter with a built-in reference optical path according to claim 1, characterized in that: The laser source is disposed at the bottom of the housing, and the reference photodetector is disposed on the side wall of the housing; The beam splitter includes a beam splitter disposed in the detection laser optical path emitted from the laser source; The detection laser emitted by the laser source is transmitted through the optical window, and the beam splitter separates the detection laser into a reference detection laser, which then illuminates the reference photodetector.
3. The laser emitter with a built-in reference optical path according to claim 1, characterized in that: Both the laser source and the reference photodetector are located at the bottom of the housing. The beam splitter includes a reflector and a beam splitter disposed in the detection laser optical path emitted from the laser source; The detection laser emitted by the laser source is transmitted through the optical window, and the beam splitter splits the detection laser into a reference detection laser. The split reference detection laser is reflected by the mirror and then illuminates the reference photodetector.
4. The laser emitter with a built-in reference optical path according to claim 2 or 3, characterized in that: The beam splitter is a semi-transparent, semi-reflective mirror.
5. The laser emitter with a built-in reference optical path according to any one of claims 1-3, characterized in that: The housing is designed as a sealed cavity and has an injection port, through which inert gas is injected into the sealed cavity.
6. The laser emitter with a built-in reference optical path according to any one of claims 1-3, characterized in that: The housing includes a cap and a base; the cap and the base are sealed together to form a sealed cavity, which is filled with an inert gas; the base is provided with pins for electrical connection with an external circuit.
7. The laser emitter with a built-in reference optical path according to claim 6, characterized in that: The housing is TO packaged.
8. The laser emitter with a built-in reference optical path according to claim 6, characterized in that: The inner wall of the cap is designed with slots or raised steps for placing the beam splitter.
9. A laser gas detection device, comprising a laser emitter, a main detector, and a control circuit module, wherein the laser emitter and the main detector are electrically connected to the control circuit module, characterized in that: The laser emitter is the laser emitter with a built-in reference optical path as described in any one of claims 1-8; The detection laser emitted by the laser emitter with the built-in reference optical path passes through the detection gas chamber and is received by the main detector and converted into a detection electrical signal; this detection electrical signal is transmitted to the control circuit module for analysis and processing to obtain the gas concentration; The reference detection laser beam split by the beam splitter is received by the reference photodetector and converted into a reference electrical signal. This reference electrical signal is then transmitted to the control circuit module for analysis and processing, and is used as a reference optical path signal for detecting optical path anomalies and system calibration.
10. The laser gas detection device according to claim 9, characterized in that: The housing contains a temperature sensor for collecting the internal temperature of the laser emitter and a temperature control chip for controlling the internal temperature of the laser emitter.