Self-alignment type laser drunk driving test device based on corner cube prism group

Abstract

The self-aligned laser-based drunk driving test device based on a pyramidal prism array provided by this invention relates to the field of optical gas detection technology. It includes: a laser emission-reception integrated unit, a signal processing and main control unit, and a pyramidal prism array retroreflective target unit integrated within a handheld main unit housing. The laser emission-reception integrated unit includes: a 3345nm DFB detection laser, a 1550nm DFB reference calibration laser, a beam combining and splitting optical module, a receiving and converging optical component, a 3345nm infrared detector, and a 1550nm infrared detector. The pyramidal prism array retroreflective target unit is formed by splicing multiple pyramidal prism units to form an array target surface. The retroreflective mechanism of the pyramidal prism array retroreflective target of this invention significantly shortens the detection time for a single vehicle, adapting to rapid screening at road checkpoints. The array expands the effective target surface, tolerates beam spot position shifts, and reduces the difficulty of on-site alignment operations.

Description

Technical Field

[0001] This invention relates to the field of optical gas detection technology, and in particular to a self-aligned laser-based drunk driving test device based on a cornerstone prism assembly. Background Technology

[0002] Driving under the influence of alcohol is a serious violation that endangers public road traffic safety. Alcohol impairs a driver's reaction time and judgment, and is one of the main causes of major traffic accidents. During roadside operations, management departments need to conduct alcohol screenings on motor vehicle drivers to quickly determine the presence of high concentrations of ethanol in the vehicle and identify vehicles suspected of being driven under the influence.

[0003] Currently, the mainstream alcohol testing methods in domestic traffic enforcement fall into two main categories: contact testing and non-contact testing. Contact devices are represented by breathalyzers, which rely on the person being tested to blow into a mouthpiece to collect an exhaled gas sample and complete the ethanol concentration test; electrochemical alcohol sensors and semiconductor gas sensors are also widely used in various simple alcohol testing devices.

[0004] However, breathalyzers are contact-based tests, requiring the test subject to actively blow air. In roadside checkpoints, vehicles need to stop one by one, and drivers need to get out to complete the sampling, which can easily cause traffic congestion during heavy traffic. Some test subjects may deliberately hold their breath or exhale in small sips, artificially interfering with the test results. In addition, the breath tube is reused by multiple people, posing a health and epidemic prevention risk. Secondly, electrochemical and semiconductor chemical gas sensors have cross-sensitivity defects. Volatile organic compounds in the vehicle environment, such as perfumes, cleaning agents, gasoline vapors, air fresheners, and disinfectant sprays, can all cause sensor malfunctions. Sensor components age and drift over time, requiring frequent calibration and maintenance. The long component response recovery time makes it impossible to achieve millisecond-level rapid measurement, which is not suitable for rapid screening scenarios in traffic flow. Summary of the Invention

[0005] The purpose of this invention is to provide a self-aligned laser drunk driving test device based on a pyramidal prism group, thereby solving the technical problems existing in the prior art.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0007] A self-aligned laser-based drunk driving test device based on a cornerstone prism array includes: a laser emission-reception integrated unit, a signal processing and main control unit, and a cornerstone prism array retroreflective target unit integrated within a handheld main unit housing; the handheld main unit housing is equipped with a human-machine interface module, and the main unit housing contains a power supply module; the laser emission-reception integrated unit includes: a 3345nm DFB detector laser and a 1550nm... The system includes a DFB reference calibration laser, a beam combining and splitting optical module, a receiving and converging optical component, a 3345nm infrared detector, and a 1550nm infrared detector. The retroreflective target unit, composed of multiple pyramidal prism units, forms an array target surface. The three reflective surfaces of each pyramidal prism unit are mutually perpendicular. A composite beam incident at any angle within the effective aperture range of the array target surface is reflected back along the antiparallel direction of incident light. The reflected dual-wavelength return beam passes through the car window glass and heat insulation film again before returning to the integrated laser transmitting and receiving unit. The signal processing and main control unit includes a signal acquisition module, a digital filtering module, a medium attenuation calibration module, an ethanol concentration calculation module, and an alarm output module. The medium attenuation calibration module calculates the overall round-trip light attenuation coefficient of the car window-film-reflective target based on the output light power of the 1550nm infrared detector. The ethanol concentration calculation module, based on the Lambert-Beer absorption law, uses the round-trip light attenuation coefficient to normalize and compensate for the attenuation of the 3345nm detection laser light power, calculating the ethanol gas concentration in the test area.

[0008] Furthermore, the beam combining and splitting optical module includes a first dichroic beam splitter, which combines the 3345nm probe laser beam and the 1550nm reference calibration laser beam to output a coaxial and unidirectional dual-wavelength composite beam; the dual-wavelength composite beam penetrates the window glass and heat insulation film of the vehicle under test and enters the test gas area inside the vehicle and illuminates the retroreflective target unit of the cornerstone prism array.

[0009] Furthermore, the effective aperture of the array target surface of the cornerstone prism array retroreflective target unit is larger than the maximum spot offset range of the dual-wavelength composite beam after refraction through the car window; the cornerstone prism array retroreflective target unit is equipped with a fixing clamp, which is used to clamp and fix it to the edge of the car window glass.

[0010] Furthermore, the receiving converging optical component includes a parabolic reflector condenser and a spherical lens; the parabolic reflector condenser performs primary convergence of the returning diverging beam, and the spherical lens compresses the spot size and projects the beam onto the corresponding detector photosensitive surface; the beam combining and splitting optical module also includes an auxiliary beam splitter and a planar deflector, which are used to steer the optical path to adapt to the internal space of the housing.

[0011] Furthermore, the spectral characteristics of the coating of the first dichroic beam splitter are set to have high transmission for one laser band and high reflection for the other laser band; the returned dual-wavelength beams guide the different wavelength beams to independent receiving optical paths.

[0012] Furthermore, the output wavelength of the 3345nm DFB detector laser is locked to the 3345nm characteristic absorption line of ethanol molecules, and the output wavelength is stabilized by a matching TEC temperature control circuit; the output wavelength of the 1550nm DFB reference calibration laser is selected from the spectral range where ethanol molecules have no molecular absorption.

[0013] Furthermore, the digital filtering module integrates a moving average filter and an adaptive bandpass filter unit to suppress ambient stray light noise and high-frequency circuit noise; the ethanol concentration calculation module has a built-in ethanol molecule absorption cross-section database, which corrects the absorption cross-section parameters in real time according to the ambient temperature and atmospheric pressure.

[0014] Furthermore, the handheld main unit housing is provided with an optical output window, and the lens of the optical output window is coated with a dual-band anti-reflection coating that is compatible with both 3345nm and 1550nm wavelengths; the main unit housing is provided with an anti-slip grip structure; the main unit housing integrates a data storage unit and an external communication interface, the communication interface being used to export detection time, ethanol concentration values, and alarm records.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (i) The retroreflection mechanism of the cornerstone prism array retroreflective target of the present invention ensures that no matter how large the incident angle is due to the refraction of the incident beam by the car window, as long as the beam falls within the aperture range of the array target, the beam will strictly return to the host receiving system along the original path in the opposite direction of incident, completely overcoming the defect of ordinary plane mirrors losing the return light when encountering the refraction of the beam by the tilted car window; the host can be handheld outside the vehicle and aligned with the car window, which greatly shortens the detection time of a single vehicle and is suitable for rapid screening at road checkpoints; the array expands the effective target surface, tolerates the position displacement of the beam spot, and reduces the difficulty of on-site alignment operation;

[0017] (II) This invention utilizes the fact that 1550nm has no absorption at ethanol molecules. The entire loss of the 1550nm laser round trip comes only from the car window glass, heat insulation film, and dirt on the surface of the reflective target. Based on this, the round trip medium attenuation coefficient is calculated. Then, the 3345nm detection light signal is normalized and corrected to eliminate all light attenuation introduced by the solid medium, and only the light power change caused by the absorption of ethanol molecules is retained. This eliminates the measurement false high caused by the car window film from the mechanism level, greatly reduces the probability of false positive alarms on site, and improves the actual law enforcement usability of the equipment.

[0018] (iii) This invention has dynamic real-time compensation capability, resists environmental disturbances, and improves the stability of measurements in complex outdoor environments;

[0019] (iv) This invention does not require sampling tubes or active exhalation by the subject. The laser penetrates the car window to directly detect the ethanol concentration in the air inside the car, without contact with personnel, thus avoiding health risks. The vehicle does not need to be turned off, and the personnel do not need to get out of the car, thus not blocking traffic flow, making it suitable for rapid initial screening at checkpoints. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating an application scenario of the self-aligned laser drunk driving test device based on a pyramidal prism group disclosed in this invention.

[0021] Figure 2 This is a schematic diagram of the overall structure of the self-aligning laser drunk driving test device based on a pyramidal prism group disclosed in this invention.

[0022] Figure 3 This is a schematic diagram of the internal optical path of the laser emission-receiver integrated unit of the self-aligned laser drunk driving test device based on a pyramidal prism group disclosed in this invention.

[0023] Figure 4 This is a schematic diagram of the original path return principle of the retroreflective target unit of the cornerstone array of the self-aligned laser drunk driving test device based on a cornerstone prism group disclosed in this invention.

[0024] Figure 5 This is a flowchart of the measurement process of the self-aligned laser drunk driving test device based on a pyramidal prism group disclosed in this invention. Detailed Implementation

[0025] To make the content of this invention easier to understand, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Identical components are represented by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, while the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0026] like Figure 1-5 As shown, this embodiment provides a self-aligning laser drunk driving test device based on a cornerstone prism array, including: a laser emission-reception integrated unit, a signal processing and main control unit, and a cornerstone prism array retroreflective target unit integrated in the handheld host housing;

[0027] The handheld main unit housing is equipped with a human-machine interface module, and the main unit housing contains a power module. The handheld main unit housing is provided with an optical output window, and the lens of the optical output window is coated with a dual-band anti-reflection film that is compatible with both 3345nm and 1550nm wavelengths to reduce the light loss introduced by the lens itself. The window is provided with a removable dustproof protective cover to protect the internal optical components from dust contamination when not in use. The main unit housing is provided with a non-slip grip structure for easy handling by the operator. The main unit housing integrates a data storage unit and an external communication interface, which is used to export detection time, ethanol concentration values, and alarm records.

[0028] The integrated laser transmitting and receiving unit includes: a 3345nm DFB detector laser, a 1550nm DFB reference calibration laser, a beam combining and splitting optical module, a receiving and converging optical component, a 3345nm infrared detector, and a 1550nm infrared detector. In this embodiment, the 3345nm DFB detector laser is a mid-infrared DFB distributed feedback laser, with its output center wavelength precisely locked at 3345nm, corresponding to the strong absorption spectrum of ethanol molecules. The 1550nm DFB reference calibration laser is a communication band DFB laser, with its output wavelength set to 1550nm, at which wavelength ethanol molecules exhibit almost no infrared vibrational absorption. The beam combining and splitting optical module includes a first dichroic beam splitter, which combines the 3345nm detector laser beam and the 1550nm reference calibration laser beam to output a coaxial, unidirectional dual-wavelength composite beam. The dual-wavelength composite beam penetrates the vehicle window glass and heat insulation film, enters the test gas area inside the vehicle, and illuminates the retroreflective target unit of the cornerstone prism array. The first dichroic beam splitter... The mirror coating spectral characteristics are set to high transmission for one laser band and high reflection for the other laser band; the returned dual-wavelength beams guide the different wavelength beams to independent receiving optical paths; specifically, when the composite beam is incident on the array target surface at any angle, as long as the light spot falls within the array aperture, the corner cube prism unit will strictly reflect the incident beam back along the antiparallel direction of the incident path; the returned dual-wavelength composite beam passes through the car window glass and heat insulation film again, and returns to the optical output window of the handheld host housing; the returned dual-wavelength composite beam enters the host and is incident on the first dichroic beam splitter; according to the wavelength split, the 3345nm return probe beam is transmitted, and the 1550nm return reference beam is reflected by the mirror surface; the two beams are separated into two independent receiving optical paths.

[0029] The receiving and converging optical assembly includes a parabolic reflector and a spherical lens. The parabolic reflector initially converges the returning diverging beam, and the spherical lens compresses the spot size, projecting the beam onto the photosensitive surface of the corresponding detector. The 3345nm returning detector beam, after convergence, is incident on the photosensitive surface of the 3345nm infrared detector. The 1550nm returning reference beam is deflected and converged by a planar deflector and is incident on the photosensitive surface of the 1550nm infrared detector. In this embodiment, the 3345nm infrared detector is an InSb infrared photodetector, adapted to the 3345nm mid-infrared band; the 1550nm infrared detector is an InGaAs photodetector, adapted to the 1550nm near-infrared band. Both detectors output analog voltage signals, which are transmitted to the signal processing and main control unit. The beam combining and splitting optical module also includes an auxiliary beam splitter and a planar deflector, which are used for optical path deflection to adapt to the internal space of the housing.

[0030] The 3345nm DFB detector laser outputs wavelengths that lock onto the 3345nm characteristic absorption line of ethanol molecules, and is equipped with a TEC temperature control circuit to stabilize the output wavelength; the 1550nm DFB reference calibration laser outputs wavelengths in the spectral range where ethanol molecules have no molecular absorption.

[0031] The retroreflective target unit of the pyramidal prism array is formed by splicing multiple pyramidal prism units to form an array target surface. In this embodiment, the pyramidal prism array consists of 9 pyramidal prism units arranged in a 3x3 matrix. Each pyramidal prism unit is made of fused silica material, and the three reflective surfaces are strictly perpendicular to each other. Each prism has an effective light-transmitting aperture of 12mm. The overall effective target surface size of the array is 40mm x 40mm. The effective light-transmitting aperture of the array target surface of the pyramidal prism array retroreflective target unit is larger than the maximum spot offset range of the dual-wavelength composite beam after refraction through the car window. The three reflective surfaces of the pyramidal prism unit are perpendicular to each other. The perpendicularity deviation between adjacent reflective surfaces is ≤2°, ensuring the consistency of the retroreflection angle from a processing precision perspective. A composite beam incident at any angle within the effective aperture range of the array target is reflected back along the antiparallel direction of incident light. The reflected dual-wavelength return beam passes through the window glass and heat insulation film again before returning to the integrated laser emission and reception unit. When the tilt angle of the vehicle window is within the normal range of 20°–45° and the measurement optical path from the outer edge of the window to the retroreflection target is 0.5–1.2 m, the maximum lateral spot offset generated by the laser beam obliquely penetrating the window glass is ≤15 mm. This offset is further calculated by adding the spot diameter formed by the beam's own divergence. The effective aperture of the array is still significantly larger than the maximum spot offset range after refraction, ensuring that the refracted beam always falls completely into the effective light-receiving area of ​​the target surface, avoiding interruption of the return signal and measurement failure due to the spot deviating from the prism boundary; the retroreflective target unit of the cornerstone prism array is equipped with a fixing clamp, which is used to clamp and fix it to the edge of the car window glass. The inner anti-slip silicone pad can avoid scratching the glass surface and the car window film, while increasing the clamping friction to prevent the target from slipping; the self-aligning retroreflective mechanism of the cornerstone prism array retroreflective target unit is: incident on any cornerstone prism unit within its effective aperture The dual-wavelength composite beam will undergo total internal reflection sequentially on three mutually perpendicular internal reflection surfaces. After three reflections, the propagation vector of the outgoing beam is strictly antiparallel to the incident beam vector. Regardless of the angle at which the incident beam enters the target surface, as long as the beam spot covers the effective light-passing area of ​​a single prism, the returning beam can be refracted back along the original incident light path and accurately return to the receiving aperture of the laser emission and reception integrated unit. No angle calibration of the reflecting target is required. From an optical principle perspective, the influence of beam deflection caused by the refraction of the car window glass on the receiving light path is completely eliminated. It is naturally adapted to car windows of different tilt angles and achieves self-alignment of the light path without adjustment.

[0032] The signal processing and main control unit includes: a signal acquisition module, a digital filtering module, a medium attenuation calibration module, an ethanol concentration calculation module, and an alarm output module;

[0033] The digital filtering module integrates moving average filtering and adaptive bandpass filtering units; it adopts a multi-channel synchronous ADC to synchronously acquire the analog signals output by two detectors, ensuring that the two optical power signals are time-aligned and eliminating errors caused by sampling time differences; it integrates moving average filtering and adaptive bandpass filtering algorithms to filter out stray light in the outdoor environment and high-frequency noise from the laser driving circuit, thereby improving the signal-to-noise ratio.

[0034] The dielectric attenuation calibration module calculates the overall round-trip optical attenuation coefficient of the window-film-reflective target based on the output optical power of the 1550nm infrared detector. Its working principle is as follows: the 1550nm wavelength corresponds to the non-absorption window of the ethanol molecule spectrum. Ethanol gas inside the vehicle does not cause characteristic absorption attenuation of this wavelength of laser light. Therefore, all power loss of the 1550nm laser in the round-trip optical path originates from non-gaseous factors such as interface reflection and bulk absorption of the window glass, absorption and scattering by the heat insulation film, decreased reflection efficiency of the cornerstone prism array retroreflective target, and dust contamination on the optical end face. This module can comprehensively characterize the attenuation effect of the solid medium and optical interface on light transmission. During calibration calculation, the module reads... The real-time return optical power of the current 1550nm channel is used to call the pre-stored dielectric reference optical power of the device, that is, the 1550nm reference return optical power corresponding to the retroreflective target at standard distance without vehicle window obstruction. The round-trip optical attenuation coefficient is obtained by ratio calculation. The module supports two working modes: static calibration and dynamic tracking. In static calibration mode, the calibration calculation is performed once for each vehicle under test, and the calibration result is cached in memory for use throughout the measurement. In dynamic tracking mode, the module continuously updates the attenuation coefficient with the sampling cycle, which can compensate for the loss fluctuation caused by dynamic changes such as vehicle vibration, target micro-movement, and condensation on the vehicle window in real time, further improving the stability of long-term continuous monitoring.

[0035] The ethanol concentration calculation module has a built-in ethanol molecule absorption cross section database. It corrects the absorption cross section parameters in real time according to the ambient temperature and atmospheric pressure, eliminating the influence of temperature and pressure fluctuations on gas absorption intensity and improving the environmental adaptability of concentration calculation.

[0036] The ethanol concentration calculation module is based on the Lambert-Beer absorption law and uses a round-trip light attenuation coefficient to normalize and compensate for the attenuation of the 3345nm detection laser light power to calculate the ethanol gas concentration in the test area. The specific steps are as follows: During the concentration calculation, the round-trip light attenuation coefficient output by the medium attenuation calibration module is first called to normalize and compensate for the return light power of the 3345nm channel, eliminating the light power loss introduced by solid media such as car window glass, heat insulation film, and target surface dirt, obtaining the effective attenuation light power caused only by ethanol gas absorption; then, based on the Lambert-Beer absorption law, the corrected effective light power, the pre-calibrated 3345nm reference light power, the effective absorption optical path inside the vehicle, and the temperature and pressure corrected absorption cross-section parameters are substituted into the absorption law inversion formula to obtain the average volume concentration of ethanol gas in the test area; this module has a built-in unit conversion subroutine that can automatically convert the volume concentration to the mass concentration unit mg / L commonly used in traffic management enforcement, and can output an equivalent breath alcohol concentration reference value according to the breath alcohol concentration conversion model, directly matching the threshold standards for drunk driving and driving under the influence of alcohol.

[0037] The alarm output module has a built-in configurable concentration threshold register, which supports setting multiple alarm thresholds according to law enforcement needs, corresponding to the drunk driving screening threshold and the drunk driving determination threshold respectively. This module reads the ethanol concentration calculation result in real time and compares it with the preset threshold: when the ethanol concentration to be measured exceeds the first-level screening threshold, an audible and visual alarm signal is output, driving the buzzer to emit a prompt sound and the red alarm indicator light to illuminate; when the concentration exceeds the second-level threshold, the alarm prompt intensity is increased, and the alarm status is automatically marked according to the current measurement data, and stored in the local storage unit along with the timestamp for subsequent law enforcement tracing.

[0038] This invention also provides a non-contact vehicle-mounted laser detection method for drunk driving using a self-aligned pyramidal prism array, comprising the following steps:

[0039] S1: Arrange the retroreflective target unit of the pyramidal prism array on the other side of the window to be tested; turn on only the 1550nm DFB reference calibration laser and collect the return optical power output by the 1550nm infrared detector; combine the pre-stored dielectric reference optical power to calculate the round-trip dielectric attenuation coefficient that includes the combined effects of the window glass, heat insulation film and the retroreflective target unit of the pyramidal prism array.

[0040] S2: Turn on the 3345nm DFB detector laser, keep the 1550nm DFB reference calibration laser working synchronously, output a coaxial composite beam, the beam penetrates the car window and enters the car, is reflected back through the cornerstone prism array retroreflective target unit, and penetrates the car window again to return to the host; synchronously collect the detection light power returned by the 3345nm infrared detector and the 1550nm return light power.

[0041] S3: Using the round-trip dielectric attenuation coefficient, the 3345nm probe light power is normalized and corrected to obtain the corrected effective light power;

[0042] S4: Based on the Lambert-Beer infrared absorption law, substitute the corrected effective optical power, combine the reference optical power, optical path length, and ethanol molecule absorption cross section, and introduce environmental temperature and atmospheric pressure compensation to calculate the ethanol gas concentration in the test path inside the vehicle. S5: Output the ethanol concentration to the human-machine interaction module for display and store the detection record; compare the ethanol concentration with the preset drunk driving screening threshold. If the concentration exceeds the threshold, trigger an audible and visual alarm. At this time, the buzzer sounds and the red alarm LED lights up to complete the alarm prompt; the operator reads the result.

[0043] It should be noted that this device can cycle through S2-S5 to achieve continuous measurement and continuous monitoring.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A self-aligning laser-based drunk driving test device based on a pyramidal prism assembly, characterized in that: include: The laser emission-receiver unit, signal processing and main control unit, and cornerstone prism array retroreflective target unit are integrated into the handheld main unit housing; The handheld host housing is equipped with a human-computer interaction module, and the host housing contains a power module. The laser transmitting-receiving integrated unit includes: a 3345nm DFB detector laser, a 1550nm DFB reference calibration laser, a beam combining and splitting optical module, a receiving and converging optical component, a 3345nm infrared detector, and a 1550nm infrared detector. The retroreflective target unit of the cornerstone prism array is formed by splicing multiple cornerstone prism units to form an array target surface; the three reflective surfaces of the cornerstone prism unit are perpendicular to each other, and the composite beam incident on the array target surface at any angle within the effective aperture range is reflected back along the incident antiparallel direction; the reflected dual-wavelength return beam passes through the car window glass and heat insulation film again and returns to the laser emission and reception integrated unit. The signal processing and main control unit includes: a signal acquisition module, a digital filtering module, a medium attenuation calibration module, an ethanol concentration calculation module, and an alarm output module; the medium attenuation calibration module calculates the overall round-trip light attenuation coefficient of the window-film-retroreflective target based on the output light power of the 1550nm infrared detector; the ethanol concentration calculation module calculates the ethanol gas concentration in the area to be measured by normalizing the attenuation of the 3345nm detection laser light power using the round-trip light attenuation coefficient based on the Lambert-Beer absorption law.

2. The self-aligned laser-based drunk driving test device based on a pyramidal prism group according to claim 1, characterized in that: The beam combining and splitting optical module includes a first dichroic beam splitter, which combines the 3345nm probe laser beam and the 1550nm reference calibration laser beam to output a coaxial and unidirectional dual-wavelength composite beam. The dual-wavelength composite beam penetrates the window glass and heat insulation film of the vehicle under test, enters the test gas area inside the vehicle, and illuminates the retroreflective target unit of the cornerstone prism array.

3. The self-aligned laser-based drunk driving test device based on a cornerstone prism group according to claim 2, characterized in that: The effective aperture of the array target surface of the cornerstone prism array retroreflective target unit is greater than the maximum spot offset range of the dual-wavelength composite beam after refraction through the car window; the cornerstone prism array retroreflective target unit is equipped with a fixing clamp, which is used to clamp and fix it to the edge of the car window glass.

4. The self-aligning laser-based drunk driving test device based on a cornerstone prism group according to claim 3, characterized in that: The receiving and converging optical component includes a parabolic reflector and a spherical lens; the parabolic reflector performs primary convergence of the returning diverging beam, and the spherical lens compresses the spot size and projects the beam onto the corresponding detector photosensitive surface; the beam combining and splitting optical module also includes an auxiliary beam splitter and a planar deflector, which are used to steer the optical path to adapt to the internal space of the housing.

5. The self-aligned laser-based drunk driving test device based on a cornerstone prism group according to claim 1, characterized in that: The first dichroic beam splitter is coated with a spectral characteristic set to have high transmission for one laser band and high reflection for the other laser band; the returned dual-wavelength beams guide the different wavelength beams to independent receiving optical paths.

6. The self-aligning laser-based drunk driving test device based on a cornerstone prism group according to claim 1, characterized in that: The 3345nm DFB detector laser outputs wavelengths that lock onto the 3345nm characteristic absorption line of ethanol molecules, and is equipped with a TEC temperature control circuit to stabilize the output wavelength; the 1550nm DFB reference calibration laser outputs wavelengths in the spectral range where ethanol molecules have no molecular absorption.

7. The self-aligned laser-based drunk driving test device based on a cornerstone prism group according to claim 1, characterized in that: The digital filtering module integrates a moving average filter and an adaptive bandpass filter unit to suppress ambient stray light noise and high-frequency circuit noise; the ethanol concentration calculation module has a built-in ethanol molecule absorption cross-section database and corrects the absorption cross-section parameters in real time according to the ambient temperature and atmospheric pressure.

8. The self-aligned laser-based drunk driving test device based on a cornerstone prism group according to claim 1, characterized in that: The handheld main unit housing is provided with an optical output window, and the lens of the optical output window is coated with a dual-band anti-reflection coating that is compatible with 3345nm and 1550nm. The main unit housing is provided with an anti-slip grip structure. The main unit housing integrates a data storage unit and an external communication interface, which is used to export detection time, ethanol concentration value, and alarm records.

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