A method for dynamic scanning and thermal coupling monitoring of high-energy light spot of vehicle light optics

Abstract

The present application relates to the technical field of optical testing and material performance analysis, and relates to a kind of car light optical high-energy light spot dynamic scanning and thermal coupling monitoring method.The present application first obtains the infrared absorption spectrum of the material to be measured car light, extracts the intrinsic infrared absorption peak wavelength of transmissivity at minimum value and constructs narrow-band filter detection channel, to realize the high signal-to-noise ratio capture of material-specific thermal radiation signal;Subsequently, a high-energy test beam is generated, which forms a dynamic high-energy light spot on the material surface through an acousto-optic modulator and a two-dimensional mechanical scanning galvanometer, and the target wavelength thermal radiation signal is collected and extracted using a coaxial reverse detection light path;At the same time, the galvanometer position identification acceleration and deceleration turning dead zone is monitored in real time, the acousto-optic modulator is controlled through hardware level closed loop to execute beam edge truncation and conduction, and the scanning start and stop position data distortion is eliminated;Finally, the signal under uniform speed scanning state is subjected to voltage peak extraction and Planck law temperature conversion, to generate the highest thermal coupling temperature of the material.

Description

Technical Field

[0001] This invention relates to the field of optical testing and material performance analysis technology, and to a method for dynamic scanning and thermal coupling monitoring of high-energy light spots in automotive lamps. Background Technology

[0002] As a critical safety and functional component of vehicles, the optical performance and long-term reliability of automotive lights are of paramount importance. With the application of new light source technologies such as laser headlights and high-power LEDs, the optical components inside automotive lights, especially lenses and lens housings made of polymer materials such as polycarbonate or polymethyl methacrylate, are subjected to increasingly high-intensity light and heat loads. Therefore, in the research and development and quality control stages, accurately testing the thermal coupling characteristics of these materials under high-energy light irradiation—that is, the material's ability and limit to absorb light energy and convert it into heat energy—is a key step in evaluating their performance and lifespan, falling under the scope of materials and structural testing and analysis.

[0003] In existing technologies, the thermal effect testing of such materials typically employs static irradiation. A common approach involves fixing the sample of the automotive lamp material under test and continuously irradiating its surface with a laser or simulated light source of fixed power, while simultaneously using a broad-spectrum infrared thermal imager to perform non-contact temperature measurements from the side or rear of the sample. The thermal response of the material is then evaluated by analyzing the temperature distribution and changes in the thermal image. Some approaches, to simulate dynamic operating conditions, utilize a mechanical translation stage to move the sample, achieving relative movement of the light spot on the material surface.

[0004] However, the aforementioned existing technical solutions have some inherent technical drawbacks. Using a broad-spectrum infrared thermal imager for temperature measurement receives all thermal radiation from the material across a wide infrared band, making the measurement results highly susceptible to interference from ambient background radiation and stray light reflection. Furthermore, the temperature measurement accuracy of the thermal imager is highly dependent on the accurate setting of the material's surface emissivity. However, the emissivity of polymer materials varies with temperature and wavelength, making precise calibration difficult and resulting in insufficient accuracy of the temperature measurement results. In addition, when simulating dynamic scanning by moving the sample, the start-stop process of the mechanical platform also involves acceleration and deceleration phases, making it difficult to precisely synchronize with the thermal imaging frame rate, leading to data distortion at the beginning and end positions of the scanning path. Summary of the Invention

[0005] In view of this, in order to solve the problems mentioned in the background technology, a method for dynamic scanning and thermal coupling monitoring of high-energy light spots of automotive lamps is proposed.

[0006] The objective of this invention can be achieved through the following technical solution: This invention provides a method for dynamic scanning and thermal coupling monitoring of high-energy light spots in automotive lamps, including: S1, acquiring the infrared absorption spectrum of the automotive lamp material to be tested, performing feature analysis on the infrared absorption spectrum to extract the intrinsic infrared absorption peak wavelength where the transmittance is at its minimum, and generating target filter wavelength parameters based on the intrinsic infrared absorption peak wavelength.

[0007] S2. Receive the target filtering wavelength parameters, configure the front-end filtering component of the single-point infrared detector according to the target filtering wavelength parameters, and construct a narrowband filtering detection channel.

[0008] S3. Generate a high-energy test beam. Input the high-energy test beam into a two-dimensional mechanical scanning galvanometer through an acousto-optic modulator. After being deflected by the two-dimensional mechanical scanning galvanometer, the beam is projected onto the surface of the vehicle lamp material under test, forming a dynamic high-energy light spot.

[0009] S4. Collect the transient thermal radiation signal excited by the dynamic high-energy light spot on the surface of the vehicle lamp material under test, and make the transient thermal radiation signal return to the two-dimensional mechanical scanning galvanometer along the incident optical path of the high-energy test beam to obtain the reverse coaxial radiation signal.

[0010] S5. Obtain the reverse coaxial radiation signal, use a dichroic beam splitter to separate the reverse coaxial radiation signal and extract the infrared beam, and guide the infrared beam into a narrowband filter detection channel to obtain the target wavelength thermal radiation signal.

[0011] S6. Extract the real-time physical position level signal of the two-dimensional mechanical scanning galvanometer, compare the real-time physical position level signal with the boundary threshold representing the dead zone of mechanical acceleration, deceleration and turning, and generate a scanning state determination command.

[0012] S7. Receive the scanning state determination command, and perform hardware-level closed-loop control of the acousto-optic modulator according to the scanning state determination command to execute the edge truncation and conduction operation of the high-energy test beam, and obtain the target wavelength thermal radiation signal under the uniform scanning state by combining the target wavelength thermal radiation signal.

[0013] S8. Acquire the target wavelength thermal radiation signal under uniform scanning state, extract the voltage peak value of the target wavelength thermal radiation signal under uniform scanning state to obtain the transient voltage peak value, perform temperature conversion on the transient voltage peak value to generate the highest thermal coupling temperature of the vehicle lamp material under test.

[0014] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: (1) The present invention pre-analyzes the intrinsic infrared absorption peak wavelength of the material to be tested for the vehicle lamp and constructs a narrowband filter detection channel based on this, so that the detection of thermal radiation signals has high material specificity. This method can accurately capture characteristic band signals directly related to the molecular structure of the material from complex full-band thermal radiation, effectively suppressing the interference of environmental background radiation and non-characteristic band thermal noise, thereby obtaining target wavelength thermal radiation signals with extremely high signal-to-noise ratio, laying a solid foundation for subsequent accurate temperature calculation.

[0015] (2) This invention employs a hardware-level closed-loop control strategy for edge truncation and conduction of the high-energy test beam. By monitoring the physical position of the two-dimensional mechanical scanning galvanometer in real time, it accurately identifies the mechanical acceleration / deceleration transition dead zones at both ends of the scanning path. In these regions of unstable speed, the system physically shuts off the high-energy test beam through an acousto-optic modulator, thereby preventing uneven heating caused by changes in the light spot dwell time and ensuring that all valid data are collected within the uniform scanning range. This proactive method of eliminating error sources guarantees the validity and reliability of the target wavelength thermal radiation signal data obtained under the uniform scanning state.

[0016] (3) This invention designs a specific coaxial scanning and reverse detection optical path, enabling transient thermal radiation signals to return along the incident path of the high-energy test beam. While scanning the outgoing beam, the two-dimensional mechanical scanning galvanometer also dynamically descans and compensates for the returning signal beam, stably converting the signal from the moving spot into a reverse coaxial radiation signal propagating along a fixed axis. This design not only achieves efficient signal collection from dynamic heat sources but also simplifies the structure of the back-end detection system, ensuring the stability and consistency of signal collection efficiency throughout the dynamic scanning process.

[0017] (4) This invention accurately locates the intrinsic infrared absorption peak by combining Fourier transform with valley search, ensuring the physical accuracy of the target filtering parameters; it improves energy utilization by using high transmittance angle and diffraction order acousto-optic modulation control corresponding to specific wavelengths; it introduces geometric collection efficiency calculation to correct optical errors caused by spatial divergence; it uses a drive motor encoder to extract real-time physical position level signals and compares them with boundary thresholds to determine the state, eliminating test artifacts caused by nonlinear acceleration and deceleration motion from the physical control layer; it substitutes the actual infrared radiative exitance into the integral formula combining Planck's law and Kirchhoff's law for iterative solution, cleverly reducing the complex and variable emissivity calibration under the wide spectrum to a constant level emissivity assignment under the narrow band, greatly improving the calculation accuracy of the highest thermal coupling temperature. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the system module structure connection of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 1 This invention provides a method for dynamic scanning and thermal coupling monitoring of high-energy light spots in automotive lamps, including: S1, acquiring the infrared absorption spectrum of the material to be tested, performing feature analysis on the infrared absorption spectrum to extract the intrinsic infrared absorption peak wavelength where the transmittance is at its minimum, and generating target filter wavelength parameters based on the intrinsic infrared absorption peak wavelength.

[0022] In a specific embodiment of the present invention, the infrared absorption spectrum of the vehicle lamp material to be tested is obtained, the intrinsic infrared absorption peak wavelength at which the transmittance is at a minimum is extracted by characteristic analysis of the infrared absorption spectrum, and the target filtering wavelength parameter is generated based on the intrinsic infrared absorption peak wavelength. This includes: obtaining the spectrometer interferogram data of the vehicle lamp material to be tested, generating broadband infrared transmission data by Fourier transform, and then performing logarithmic conversion of absorbance to generate the infrared absorption spectrum.

[0023] By searching for valleys in the infrared absorption spectrum, the wavelength of the intrinsic infrared absorption peak where the transmittance is at its minimum is extracted from the spectral range with the lowest transmittance.

[0024] Extract the center wavelength and half-width of the intrinsic infrared absorption peak wavelength where the transmittance is at its minimum, and combine the center wavelength and half-width values ​​to generate the target filter wavelength parameters.

[0025] Specifically, this step aims to determine a suitable wavelength channel for subsequent thermal radiation signal detection by analyzing the optical properties of the material used in the test lamp. The entire process begins with acquiring spectroscopic interferogram data of the material, a dataset recording the percentage of infrared light that can penetrate the material over a wide range of infrared wavelengths. This data is typically obtained using a Fourier transform infrared spectrometer, which can quickly and accurately measure the material's transmittance across continuous wavelengths.

[0026] After acquiring the interferogram data from the spectrometer, it needs to be processed using a Fourier transform to convert the interferogram signal acquired by the instrument into easily analyzable broadband infrared transmission data (infrared transmission spectrum). Then, the logarithmic formula of the Lambert-Beer law is used for further conversion to finally generate the infrared absorption spectrum. The infrared absorption spectrum describes the material's ability to absorb infrared radiation, and it is numerically correlated with the transmission spectrum. Lower transmittance indicates stronger absorption. The relationship between transmittance and absorbance can be expressed by the following formula:

[0027] In the formula, Represents wavelength Absorption at that location This represents the transmittance at the same wavelength. Transmittance It is defined as the ratio of the light intensity passing through the material of the vehicle headlight being tested to the incident light intensity:

[0028] in, It is a wavelength of The intensity of infrared light after passing through the material of the vehicle headlight under test. This refers to the incident light intensity measured when the test headlight material is not placed.

[0029] Next, a valley search is performed on the generated infrared absorption spectrum. Here, "valley" specifically refers to the minimum point in the transmission spectrum, corresponding to the maximum point in the absorption spectrum. Through algorithms or manual analysis, the spectral range with the lowest transmittance is found across the entire spectrum. This range exists because the molecular structure of the material vibrates or rotates under specific wavelengths of infrared light, thus strongly absorbing the energy of that wavelength. These specific wavelengths constitute the material's "fingerprint" information. In these strong absorption regions, the material is almost opaque, and the transmittance reaches a minimum. The wavelength extracted from these regions is the intrinsic infrared absorption peak wavelength, representing the material's intrinsic and significant infrared absorption characteristics.

[0030] After locating the intrinsic infrared absorption peak wavelength, it needs to be quantitatively characterized. Specifically, this involves extracting the center wavelength and half-width at half-maximum (HWHM) of this absorption peak. The center wavelength is the precise wavelength corresponding to the point of strongest absorption and lowest transmission. The HWHM, usually referring to the full width at half maximum (FWHM), describes the width of the absorption peak and is the wavelength range corresponding to half the peak height. For a transmission valley, the HWHM is calculated as follows: Because the absorption characteristics of materials follow the logarithmic law of the Lambert-Beer calculation, directly calculating transmittance linearly will lead to severe half-width distortion. Therefore, it is necessary to first find the lowest transmittance at the valley level. and baseline transmittance far from the absorption peak region Converted into the corresponding maximum absorption rate and baseline absorbance Then, the absorbance threshold corresponding to the full width at half maximum (FWHM) is calculated on the absorbance curve: Finally, the absorbance threshold is mapped back to the transmittance domain to obtain its corresponding threshold transmittance. Find the transmittance equal to on the transmission spectrum. The wavelengths corresponding to the two points The absolute value of the difference between these two wavelengths This is the half-width value after precise correction.

[0031] Finally, the extracted center wavelength value and half-width value are combined to generate the target filtering wavelength parameter. This parameter is a data structure containing two values ​​that precisely defines a wavelength channel. The subsequent detection system will be configured based on this parameter to ensure that only thermal radiation signals from the material's strongest absorption band are received, thereby effectively improving the signal-to-noise ratio and accuracy of the detection. It can be represented as:

[0032] in, It is the center wavelength value. This refers to the half-width value. Both of these values ​​are in units of length, such as micrometers (µm). ), with consistent dimensions.

[0033] For example, using a common automotive lighting material, polycarbonate (PC), as the material to be tested, the implementation process of step S1 is illustrated.

[0034] First, a 2-millimeter-thick polycarbonate sample was placed in a Fourier transform infrared spectrometer and scanned within a wavelength range of 2.5 to 25 micrometers to obtain its broadband infrared transmission data. After Fourier transform processing by the instrument's built-in function, the infrared absorption spectrum of the test vehicle lamp material was obtained.

[0035] Analysis of the infrared absorption spectrum revealed absorption peaks at multiple locations. Based on statistical analysis of 200 sets of measured data from industrial sensors, we found a very strong and isolated absorption peak in the long-wave infrared region, suitable as a characteristic peak. Using a valley search algorithm, we located the spectral range with the lowest transmittance, and its data points are shown in the table below (partial data): | Wavelength ( |Transmittance|, |9.45|0.46|, |9.50|0.25|, |9.55|0.10|, |9.60|0.02|, |9.65|0.11|, |9.70|0.28|, |9.75|0.46|.

[0036] As can be seen from the data in the table above, the transmittance reaches a minimum of 0.02 at a wavelength of 9.60 micrometers. Therefore, the intrinsic infrared absorption peak wavelength at this location is extracted.

[0037] Next, the center wavelength and half-width at half-maximum (WHM) values ​​are extracted based on this absorption peak. Center wavelength value That is, the wavelength corresponding to the point of lowest transmittance, so Micrometers. To calculate the half-width at half-maximum (WWHM) value, the baseline transmittance needs to be determined. Assuming the average transmittance of the material (baseline transmittance) in a region far from this absorption peak... The lowest transmittance at the valley floor is 0.90. It is 0.02. Converting this to absorbance: Calculate the half-maximal absorbance: The corresponding transmittance threshold By searching the spectral data or through interpolation, the two wavelengths corresponding to a transmittance of 0.134 were found to be... micrometers and Micrometers. Calculate the half-width value: Micrometer.

[0038] Finally, by combining the center wavelength and half-width values, the target filter wavelength parameters are generated as {9.60 μm, 0.16 μm}. This parameter will be sent to subsequent steps to construct a narrowband filter detection channel centered at 9.60 μm and with a bandwidth of approximately 0.16 μm.

[0039] S2. Receive the target filtering wavelength parameters, configure the front-end filtering component of the single-point infrared detector according to the target filtering wavelength parameters, and construct a narrowband filtering detection channel.

[0040] In a specific embodiment of the present invention, receiving the target filtering wavelength parameters and configuring the front-end filtering component of the single-point infrared detector according to the target filtering wavelength parameters to construct a narrowband filtering detection channel includes: parsing the target filtering wavelength parameters and extracting the center wavelength value and half-width value of the limited infrared wavelength window.

[0041] Select or adjust the front-end filter component based on the center wavelength and half-width values, so that the center transmission wavelength of the front-end filter component is equal to the center wavelength value, and the full width at half maximum (FWHM) and half-width at half maximum (WHM) values ​​of its transmission characteristics are equal.

[0042] A front-end filter component with the required transmission characteristics is installed in front of the photosensitive front of a single-point infrared detector to filter out background thermal radiation and stray light interference outside a specific wavelength range, thereby constructing a narrowband filter detection channel targeting the material's characteristic absorption peaks.

[0043] Specifically, this step takes advantage of the unique optical fingerprint information of the test vehicle lamp material generated in the previous step and uses this information to construct a highly specific signal detection path. The entire process begins with receiving the target filter wavelength parameters transmitted from step S1. These parameters include the center wavelength value and the half-width value, which together define the infrared wavelength window.

[0044] After receiving the target filtering wavelength parameters, the core task is to configure the front-end filtering component of the single-point infrared detector based on these parameters. A single-point infrared detector is a sensor that converts incident infrared radiation energy into an electrical signal. It responds to a wide range of infrared light but cannot distinguish between radiation sources of different wavelengths. The front-end filtering component, on the other hand, is a precision optical element, typically a multilayer dielectric interference filter. Its function is to allow only light within a specific wavelength range to pass through, while reflecting or absorbing light of all other wavelengths. Combining the two allows for selective detection of signals at specific wavelengths.

[0045] The configuration process involves selecting or adjusting a front-end filter component for the single-point infrared detector to ensure its transmission spectral characteristics perfectly match the target filtering wavelength parameters. The center transmission wavelength of the selected front-end filter component must be equal to the center wavelength value in the target filtering wavelength parameters, and its transmission bandwidth, typically measured by full width at half maximum (FWHM), must also correspond to the FWHM value in the target filtering wavelength parameters. The transmission performance of the front-end filter component can be accurately described by its transmittance function. The transmittance function of a typical Gaussian bandpass filter can be expressed as:

[0046] In the formula, The front-end filtering component is at the wavelength The transmittance at that point is a dimensionless proportional value. This represents the peak transmittance of the component at the center wavelength. Its value is determined by the filter manufacturing process and is usually obtained from the product specification sheet. It is the wavelength of the incident light. It is the center wavelength of the front-end filter component, and its setting value is directly taken from the center wavelength value in the target filter wavelength parameter. This refers to the full width at half maximum (FWHM) of the front-end filter component, whose set value is directly taken from the FWHM value in the target filter wavelength parameter. The constants in the formula... It is a guarantee The coefficient that conforms to the definition of full width at half maximum (FWHM). In this formula, The dimensions of all terms are length, therefore the exponent is a dimensionless number, ensuring the dimensionality consistency of the entire formula.

[0047] By having the above By mounting a front-end filter component with transmission characteristics in front of the photosensitive area of ​​a single-point infrared detector, a narrowband filtered detection channel was successfully constructed. This channel only allows wavelengths within the specified range. Nearby, width approximately The infrared radiation is focused into the detector, while background radiation and stray light of all other wavelengths are blocked. The advantage of this is that the subsequently detected thermal radiation signal will mainly originate from the thermal emission of the material under test at the intrinsic infrared absorption peak wavelength, effectively improving the signal-to-noise ratio and measurement accuracy.

[0048] For example, continuing from the example of polycarbonate automotive lamp material under test in step S1, the target filter wavelength parameter received by the system The values ​​are {9.60 micrometers, 0.30 micrometers}.

[0049] Based on the target filtering wavelength parameters, the system requires a front-end filtering component. In this embodiment, the detection system is equipped with a motorized filter wheel containing multiple interference filters of different specifications. After receiving the target filtering wavelength parameters, the control system queries the filter library and instructs the filter wheel to rotate, switching an optical filter with a center wavelength of 9.60 micrometers and a half-width at half-maximum (WWHM) of 0.30 micrometers into the optical path. This filter is precisely positioned directly in front of the incident window of a liquid nitrogen-cooled mercury cadmium telluride (MCT) single-point infrared detector.

[0050] The selected front-end filter component has a peak transmittance It has been calibrated to 0.85. According to the formula, its transmittance function... Specifically:

[0051] The effectiveness of this configuration can be verified through calculation. When the incident light wavelength... The transmittance reaches its maximum value at a wavelength of 9.60 micrometers. When the incident light wavelength deviates from the center to the edge of the half-width value, that is... At 1 micrometer or 9.45 micrometers, the transmittance is This is exactly half the peak transmittance, which perfectly matches the 0.30-micron half-width setting in the target filtering wavelength parameters. However, for background thermal radiation far from this band, such as an interference source with an emission peak at 10.5 microns, its transmittance... It will approach zero, thus being effectively filtered out.

[0052] Through the above operations, a narrowband filtered detection channel centered at 9.60 micrometers and with a bandwidth of 0.30 micrometers was constructed. This channel lays a solid foundation for subsequent accurate measurement of the characteristic wavelength thermal radiation signal of the automotive lamp material under test after being excited and heated.

[0053] S3. Generate a high-energy test beam. Input the high-energy test beam into a two-dimensional mechanical scanning galvanometer through an acousto-optic modulator. After being deflected by the two-dimensional mechanical scanning galvanometer, the beam is projected onto the surface of the vehicle lamp material under test, forming a dynamic high-energy light spot.

[0054] In a specific embodiment of the present invention, a high-energy test beam is generated, and the high-energy test beam is input to a two-dimensional mechanical scanning mirror through an acousto-optic modulator. After being deflected by the two-dimensional mechanical scanning mirror, the beam is projected onto the surface of the vehicle lamp material to be tested to form a dynamic high-energy light spot. This includes generating a high-energy test beam with a wavelength that matches the high transmittance characteristics of the vehicle lamp material to be tested, and guiding the high-energy test beam into the acousto-optic modulator.

[0055] A radio frequency electrical signal is applied to the acousto-optic modulator to generate an acoustic wave field inside it. The acoustic wave field is used to diffract the incident high-energy test beam. A beam of a specific diffraction order is extracted and the beam is transmitted to a two-dimensional mechanical scanning galvanometer after passing through a dichroic beam splitter preset on the main optical axis at an incident angle corresponding to the high transmittance of the wavelength.

[0056] An external control signal is input to the two-dimensional mechanical scanning galvanometer to drive its reflector surface to deflect in two dimensions. The deflected beam is then projected onto the surface of the vehicle lamp material under test through a flat-field focusing lens. The projection position is changed by combining the geometric mapping relationship between the deflection angle and the lens focal length, forming a dynamic high-energy light spot that moves on its surface according to the command.

[0057] Specifically, the core of this step lies in creating a controllable, mobile energy input source to rapidly heat a localized area of ​​the surface of the lamp material under test, preparing for subsequent thermal radiation signal acquisition. The entire process begins with the generation of a high-energy test beam, which is usually produced by a laser. The wavelength selection must match the characteristics of the lamp material under test, generally choosing a band with high material transmittance, such as the visible light band, to ensure that energy is mainly deposited on the material surface rather than absorbed in bulk.

[0058] Before entering the scanning system, the generated high-energy test beam passes through an acousto-optic modulator. An acousto-optic modulator is a device that uses the interaction of sound and light waves to control the intensity, frequency, or direction of a light beam. Here, it primarily acts as a high-frequency switch or intensity regulator, generating a traveling sound wave field within an internal crystal by applying a radio frequency (RF) signal. The incident high-energy test beam diffracts as it passes through this sound wave field. Only beams of a specific diffraction order (typically first-order diffraction) are allowed to enter the subsequent optical path, and their optical power is directly related to the power of the applied RF signal, providing the physical basis for rapid on / off control of the beam in subsequent steps.

[0059] The high-energy test beam, modulated by an acousto-optic modulator, first passes through a dichroic beam splitter embedded in the coaxial main optical path before being guided into the two-dimensional mechanical scanning mirror. The two-dimensional mechanical scanning mirror is a precision beam deflection system consisting of two independently controlled mirrors. One mirror deflects the beam in one dimension (e.g., the X-axis), while the other deflects it in the perpendicular dimension (Y-axis). A high-precision motor drives the mirrors to rapidly oscillate at minute angles, thereby achieving two-dimensional control of the high-energy test beam's exit direction within a predetermined scanning range in the two-dimensional plane.

[0060] The deflection angles of the two mirrors in the two-dimensional mechanical scanning galvanometer are determined by external control signals. The changes in these two angles over time determine the position of the high-energy test beam projected onto the surface of the vehicle headlight material under test. The relationship between the position coordinates of the light spot on the material surface and the galvanometer deflection angles can be described using geometric optics. Assume the scanning system includes a flat-field focusing lens with a focal length of... Then the coordinates of the light spot on the surface of the headlight material under test are... Real-time deflection angle of the two galvanometers The relationship is:

[0061]

[0062] When the deflection angle is very small, the above relationship can be simplified to a linear relationship:

[0063]

[0064] In the formula, It is a dynamic high-energy light spot in time The two-dimensional coordinates formed on the surface of the material of the vehicle headlight under test, in meters. It is the focal length of the scanning lens, measured in meters. It is the time of the two galvanometer reflecting mirrors The deflection angle relative to the centerline of the beam's incident direction is measured in radians. Since the deflection angle is a function of time, the position of the beam spot projected onto the material surface also changes over time, thus forming a dynamic high-energy beam spot that moves across the material surface. The movement speed, path, and residence time of this dynamic high-energy beam spot are entirely controlled by the driving signal applied to the two-dimensional mechanical scanning galvanometer.

[0065] For example, following the steps described above, it is now necessary to perform a heating test on the polycarbonate automotive lamp material to be tested.

[0066] The system uses a continuous-output solid-state laser with a wavelength of 532 nm to generate a high-energy test beam with a power of 10 watts. The 532 nm wavelength was chosen because polycarbonate material has high transmittance at this wavelength, allowing energy to reach the material surface without obstruction.

[0067] The generated high-energy test beam first passes through an acousto-optic modulator. In this step, the acousto-optic modulator temporarily operates in a fully open state to ensure that the 10-watt laser power can enter the subsequent system.

[0068] Subsequently, the high-energy test beam enters a two-dimensional mechanical scanning galvanometer system, which is equipped with a flat-field focusing lens with a focal length of [missing information]. The diameter is 160 mm. To form a linear scanning trajectory on the surface of the lamp material under test, the control system sends a constant signal to the Y-axis driver of the two-dimensional mechanical scanning mirror, keeping it at zero position. Simultaneously, a periodic triangular wave signal is sent to the X-axis driver, causing the X-axis galvanometer to deflect at an angle... exist 0.03 radians to It oscillates back and forth at a constant speed within a range of 0.03 radians.

[0069] According to the formula This allows for the calculation of the scanning range of the dynamic high-energy light spot on the surface of the vehicle headlight material under test. When In radians, Millimeters. When In radians, Millimeters. Therefore, a dynamic high-energy light spot scanning line with a total length of 9.6 millimeters was formed on the surface of the test vehicle headlight material. If the single-pass scanning time of the triangular wave is set to 9.6 milliseconds, then the scanning speed of the dynamic high-energy light spot is... mm / s.

[0070] Ultimately, a dynamic high-energy light spot with a power of 10 watts and moving in a straight line along the surface of the polycarbonate automotive lamp material under test at a speed of 1000 mm / s was successfully created, providing a precisely controlled energy source for exciting and collecting transient thermal radiation signals in subsequent steps.

[0071] S4. Collect the transient thermal radiation signal excited by the dynamic high-energy light spot on the surface of the vehicle lamp material under test, and make the transient thermal radiation signal return to the two-dimensional mechanical scanning galvanometer along the incident optical path of the high-energy test beam to obtain the reverse coaxial radiation signal.

[0072] In a specific embodiment of the present invention, the transient thermal radiation signal excited by the dynamic high-energy light spot on the surface of the vehicle lamp material under test is collected, and the transient thermal radiation signal is reversed along the incident optical path of the high-energy test beam and returned to the two-dimensional mechanical scanning galvanometer to obtain the reverse coaxial radiation signal. This includes: capturing the full-band thermal radiation energy generated when the dynamic high-energy light spot moves on the surface of the vehicle lamp material under test, and collecting the transient thermal radiation signal by spatial angular constraint of the full-band thermal radiation energy.

[0073] The transient thermal radiation signal is guided into the emitting lens group of the high-energy test beam, so that the transmission trajectory of the transient thermal radiation signal completely coincides with the transmission trajectory of the high-energy test beam to achieve reverse transmission.

[0074] The reverse-transmitted transient thermal radiation signal is projected onto the reflective surface of a two-dimensional mechanical scanning galvanometer, and the reverse coaxial radiation signal is obtained by dynamically compensating for the spot displacement through the reflective surface.

[0075] Specifically, this step follows immediately after the high-energy test beam excites the material. Its core task is to efficiently and accurately capture the weak thermal signal generated by localized heating and convert it into a stable and easily analyzable beam. When the dynamic high-energy beam formed in step S3 moves across the surface of the material being tested, the material temperature at the point where the beam hits increases instantaneously, and according to the basic laws of thermal radiation in physics, it emits electromagnetic radiation outward. This radiation signal generated by the temperature rise is the transient thermal radiation signal.

[0076] The entire collection process begins with capturing the full-band thermal radiation energy generated as a dynamic high-energy light spot moves across the surface of the lamp material under test. Any object with a temperature emits thermal radiation, the intensity and spectral distribution of which are directly related to temperature. Since the heating effect of the dynamic high-energy light spot is instantaneous, the generated thermal radiation is also transient and covers a broad band from near-infrared to far-infrared, hence the term "full-band thermal radiation energy." However, this energy is diffused in all directions; to utilize it effectively, spatial angular constraints must be applied to collect the transient thermal radiation signal. This spatial angular constraint is naturally achieved by the emitting lens group of the high-energy test beam, i.e., the lens used to focus the beam in step S3. This lens can only collect light emitted from its focal position within its effective aperture angle range. Based on Lambert's law of thermal radiation, the heated spot on a material surface can be considered a diffuse radiation source. Its geometric collection efficiency within a specific solid angle is not simply a matter of the solid angle's spatial proportion, but is modulated by cosine radiation characteristics and directly determined by the square of the sine of the lens's half-angle of collection. Geometric collection efficiency This can be calculated using the lens parameters:

[0077] in, It is the collection half-angle of the lens, which is related to the effective aperture diameter of the lens. and focal length Related, relationship is . In the formula, The units are all lengths, which makes The dimensionless radius is radians. The unit is steradian, which is a dimensionless geometric collection efficiency ratio, and the formula has consistent dimensions.

[0078] The collected transient thermal radiation signal is then guided into the emitting lens group of the high-energy test beam. Based on the principle of optical path reversibility, the light ray emitted from the focal point propagates in reverse along its original path and exits parallel to the principal optical axis again. Therefore, the transmission trajectory of the transient thermal radiation signal completely coincides with the transmission trajectory of the high-energy test beam, achieving reverse transmission. At this point, between the lens and the two-dimensional mechanical scanning galvanometer, the transient thermal radiation signal and the high-energy test beam propagate along the same spatial path, but in opposite directions.

[0079] Next, the reverse-transmitted transient thermal radiation signal is projected onto the reflector of a two-dimensional mechanical scanning galvanometer. Since the reflector is still rapidly deflecting according to a preset program to drive a dynamic high-energy light spot across the material surface, the transient thermal radiation signals returning from different positions will be incident on the reflector at different angles. The principle is that by dynamically compensating for the light spot displacement through the reflector, a reverse coaxial radiation signal can be obtained. Specifically, the scanning mirror deflects the beam at an angle upon exiting the beam. This allows the light spot to reach the desired position. When from location When the thermal radiation signal returns, it is at an angle (Relative to the central axis) Incident on the scanning mirror, after the same deflection After specular reflection, its exit angle is compensated to zero. This process, called "de-scanning," converts a signal from a moving point into a beam of light with a fixed direction that always propagates along the optical axis of the system's center—a counter-coaxial radiation signal.

[0080] For example, continuing from the example of step S3 above, a dynamic high-energy light spot with a power of 10 watts is moving at a speed of 1000 mm / s on the surface of the polycarbonate test vehicle lamp material.

[0081] When a dynamic high-energy light spot sweeps across a point on the material surface, the temperature at that point rises sharply, emitting full-frequency thermal radiation energy. This energy is absorbed by a beam located directly above the beam, at a focal length of [missing information]. With an effective aperture diameter of 160 mm. Captured by a 25mm emission lens group. According to the formula, the collection half-angle of this lens... Radius. Corresponding geometric collection efficiency. This means that of the total infrared thermal radiation power emitted from the surface of the material micro-element into the hemispherical space, about 0.607% can fall within this spatial angle and be effectively collected, forming a transient thermal radiation signal.

[0082] Suppose at a certain moment The dynamic high-energy light spot is located on the scanning path. At a distance of millimeters. The transient thermal radiation signal emitted from this point is collected by the lens, enters the emitting lens group of the high-energy test beam, and propagates in reverse along the optical path of the high-energy test beam to that point. At this time, the propagation trajectory of the transient thermal radiation signal completely coincides with the propagation trajectory of the high-energy test beam.

[0083] The reverse-transmitted transient thermal radiation signal is incident on the X-axis reflecting mirror of the two-dimensional mechanical scanning galvanometer at a specific angle. This angle is precisely the angle previously used to guide the beam. The negative value of the deflection angle set at the millimeter position. At what moment, the deflection angle of the X-axis reflecting mirror radians (according to) (Calculated). When the tilted thermal radiation beam carrying positional information is reflected by this deflecting mirror, its angle is dynamically compensated, and the direction of the reflected beam becomes completely parallel to the system's principal optical axis. Regardless of where the dynamic high-energy spot is on the material surface, the returned transient thermal radiation signal, after passing through the reflecting mirror of the two-dimensional mechanical scanning galvanometer, will be corrected into a beam propagating along the same fixed path. This dynamically compensated, direction-fixed beam is the final obtained reverse coaxial radiation signal, ready to be sent to the subsequent analysis system.

[0084] S5. Obtain the reverse coaxial radiation signal, use a dichroic beam splitter to separate the reverse coaxial radiation signal and extract the infrared beam, and guide the infrared beam into a narrowband filter detection channel to obtain the target wavelength thermal radiation signal.

[0085] In a specific embodiment of the present invention, the process of obtaining a reverse coaxial radiation signal, using a dichroic beam splitter to separate the reverse coaxial radiation signal and extract an infrared beam, and then guiding the infrared beam into a narrowband filter detection channel to obtain a target wavelength thermal radiation signal includes: receiving the reverse coaxial radiation signal, projecting the reverse coaxial radiation signal onto the surface of the dielectric film of the dichroic beam splitter, and using the wavelength selectivity of the dielectric film to separate the beam.

[0086] A high-energy test beam in the visible light band is transmitted through the infrared band radiation energy, and the reflected radiation energy is extracted as the infrared band beam.

[0087] The infrared beam is focused and directed into a narrowband filter detection channel. The background radiation interference other than the target filter wavelength parameter is filtered out by the front-end filter component to obtain the target wavelength thermal radiation signal.

[0088] Specifically, this step aims to precisely separate and purify the core thermal radiation information required for the study from the highly mixed optical signal obtained in the previous step. The entire process begins with acquiring the reverse coaxial radiation signal returned from the two-dimensional mechanical scanning galvanometer. Although this signal is uniform in its spatial path, it is complex in its spectral composition. It contains both the full-band transient thermal radiation signal emitted from the surface of the lamp material under test and may also contain some high-energy test beams reflected back from the material surface.

[0089] To achieve spectral separation, the system receives the reverse coaxial radiation signal and projects it onto the dielectric film surface of a dichroic beam splitter. A dichroic beam splitter is a special optical element whose surface is coated with multiple layers of precisely controlled dielectric films. Utilizing the principle of thin-film interference, it exhibits distinctly different reflection and transmission characteristics for different wavelengths of light; this is the wavelength selectivity of the dielectric film. By carefully designing the film structure, high reflection for a specific wavelength band and high transmission for another can be achieved.

[0090] In this application, the dichroic beam splitter is designed to transmit high-energy test beams in the visible light band and reflect infrared radiation energy. The wavelength of the high-energy test beam is typically in the visible light range, while the thermal radiation energy generated by the material is mainly concentrated in the infrared band. When a counter-coaxial radiation signal is incident on the dichroic beam splitter, its visible light component penetrates the beam splitter, while the infrared component is reflected. The system extracts the reflected radiation energy as an infrared beam, thus completing the initial separation of the excitation light and the thermal radiation signal. This separation process can be described by the reflectivity function of the beam splitter. and transmittance function To describe, among which (Ignoring absorption). Spectral power distribution of the incident reverse coaxial radiation signal. The spectral power of the separated infrared beam for:

[0091] In the formula, The units are all watts per micrometer (W / m²). ), representing the wavelength Power density at that location. It is a dichroic beam splitter at wavelength The reflectivity at a given point is a dimensionless value.

[0092] After obtaining the infrared beam, further signal purification is required. The infrared beam is focused by a focusing lens and directed into the narrowband filtered detection channel constructed in step S2. Within this channel, a front-end filtering component performs secondary filtering on the infrared beam. The transmission characteristics of the front-end filtering component are described. It is precisely set according to the target filtering wavelength parameters determined in step S1. It filters out background radiation interference beyond the target filtering wavelength parameters; this interference may originate from the environment or from non-characteristic thermal radiation of materials in other wavelength bands. Ultimately, only the radiation energy in an extremely narrow band that conforms to the target filtering wavelength parameters can reach the photosensitive surface of the single-point infrared detector. The detector converts this into an electrical signal, which is the final acquired target wavelength thermal radiation signal. The optical power reaching the detector... It can be represented as:

[0093] In the formula, The unit is watt ( ), representing the total optical power received by the detector. This is the transmittance function of the front-end filter component, and is a dimensionless value. The integration operation covers all wavelengths, but because... The bandpass characteristic of the filter is that the integral value is not zero only in a very narrow range near the target filter wavelength parameter.

[0094] For example, following the aforementioned steps, the system acquires the reverse coaxial radiation signal reflected from the surface of the polycarbonate automotive lamp material under test. This signal includes reflected laser light with a wavelength of 532 nanometers and infrared thermal radiation emitted from the material surface, covering a range of 2.5 micrometers to 25 micrometers.

[0095] The system projects this reverse coaxial radiation signal at a 45-degree angle onto the surface of the dielectric film of a dichroic beam splitter. This dichroic beam splitter is specially designed, and the wavelength selectivity of its dielectric film is as follows: for light with wavelengths less than 700 nanometers, the transmittance exceeds 95%; for light with wavelengths greater than 2 micrometers, the reflectance exceeds 98%.

[0096] Therefore, when a counter-coaxial radiation signal is incident, the majority of the 532-nanometer visible light component passes through the dichroic beam splitter and is absorbed by an optical trap. The infrared radiation energy, containing all thermal radiation information from 2.5 micrometers to 25 micrometers, is reflected with an efficiency exceeding 98%, and the reflected beam forms a 90-degree angle with the incident beam. The system extracts this reflected radiation energy, which constitutes the infrared beam with an initially improved signal-to-noise ratio.

[0097] Subsequently, a zinc selenide lens transparent to infrared light is used to focus the infrared beam and guide it into a previously constructed narrowband filtered detection channel. At the channel entrance is a front-end filter assembly configured according to the target filtering wavelength parameters {9.60 μm, 0.30 μm}. When the broadband infrared beam passes through this assembly, only light with wavelengths centered at 9.60 μm and within a 0.30 μm bandwidth can pass through; background radiation interference at all other wavelengths, such as the weak thermal radiation from the material at 8 μm or 11 μm, is effectively filtered out.

[0098] Finally, the light beam passing through the front-end filter assembly illuminates the mercury cadmium telluride single-point infrared detector, which converts the received optical power into a voltage signal that varies over time. The intensity of this voltage signal is only related to the thermal radiation intensity of the material under test in the 9.60-micron characteristic absorption band, which is the target wavelength thermal radiation signal finally obtained in this step.

[0099] S6. Extract the real-time physical position level signal of the two-dimensional mechanical scanning galvanometer, compare the real-time physical position level signal with the boundary threshold representing the dead zone of mechanical acceleration, deceleration and turning, and generate a scanning state determination command.

[0100] In a specific embodiment of the present invention, the real-time physical position level signal of the two-dimensional mechanical scanning galvanometer is extracted, and the real-time physical position level signal is compared with the boundary threshold characterizing the dead zone of mechanical acceleration, deceleration and turning, to generate a scanning state determination command, including: the encoder of the drive motor connected to the two-dimensional mechanical scanning galvanometer, and the extraction of the real-time physical position level signal from the encoder of the drive motor.

[0101] The current deflection angle of the two-dimensional mechanical scanning galvanometer is obtained by analyzing the real-time physical position level signal, and then compared with the boundary threshold that characterizes the dead zone of mechanical acceleration, deceleration and turning.

[0102] Determine whether the current deflection angle is within the uniform scanning range defined by the boundary threshold, and generate a scanning status determination command based on the determination result.

[0103] Specifically, the purpose of this step is to monitor the motion state of the two-dimensional mechanical scanning galvanometer in real time to distinguish between valid and invalid measurement intervals, providing crucial control commands for subsequent data purification. When the two-dimensional mechanical scanning galvanometer performs reciprocating scans, its turning points at both ends inevitably undergo a process of deceleration, stopping, and then accelerating again; this region is called the mechanical acceleration / deceleration turning dead zone. Within this region, the moving speed of the dynamic high-energy light spot is not constant, leading to uneven heating of the material and thus distorting the acquired thermal radiation signal. Therefore, these regions must be accurately identified and marked.

[0104] The entire process is initiated by a drive motor encoder connected to a two-dimensional mechanical scanning galvanometer. The drive motor encoder is a precision sensor that monitors the position of the motor shaft as the reflector of the drive galvanometer deflects in real time and converts it into a continuously changing electrical signal, which is the real-time physical position level signal.

[0105] After acquiring the real-time physical position level signal, it needs to be analyzed to obtain the current deflection angle with clear physical meaning. To meet the requirements of microsecond-level hardware synchronization and avoid software interruption delays in the operating system, this embodiment relies on a hardware main control board with low-level microsecond response capabilities, such as a Field Programmable Gate Array (FPGA) or Digital Signal Processor (DSP), to perform the following analysis and comparison operations. The real-time physical position level signal is usually a voltage or digital pulse count, which has a definite linear correspondence with the actual deflection angle of the galvanometer reflector. This relationship can be obtained through calibration or by consulting the equipment specifications and can be expressed by the following formula:

[0106] In the formula, It is in time The current deflection angle, in radians. It is the real-time physical position level signal output by the encoder of the drive motor, and the unit is volts. It is the encoder's conversion factor, measured in radians per volt. Its value is set based on the calibration results of 200 sets of industrial sensor measured data to ensure conversion accuracy. It is the angular offset, used to correct the zero point position, and the unit is radians.

[0107] After determining the current deflection angle, it is compared with a set of preset boundary thresholds. These boundary thresholds are two specific angle values ​​that together define the range of the dead zone during mechanical acceleration / deceleration. One of these thresholds is a lower limit. and an upper limit A central region is defined, within which the movement of the galvanometer is considered to be uniform; this region is the uniform scanning interval.

[0108] In a specific embodiment of the present invention, the typical value of the boundary threshold is usually set as a deflection angle accounting for 10% to 20% of the total reciprocating scanning angular distance at both ends, preferably 15% at each end, that is, defining the 70% area of ​​the global center as the stable uniform speed scanning interval. The underlying physical basis for setting this boundary threshold range is that, due to the inherent mechanical inertia of the reflector of the two-dimensional mechanical scanning galvanometer and the rotor of the drive motor, it will inevitably experience an insurmountable deceleration, zero-speed crossing, and reverse acceleration nonlinear motion process at the turning point of the reciprocating trajectory; in addition, the tracking phase delay of the servo closed-loop PID algorithm inside the driver causes the dwell time of the dynamic spot in this interval to be unnaturally lengthened. If no threshold is set to eliminate it, the abnormal accumulation of beam energy will cause the polymer transparent material to exhibit a thermal ablation artifact under unrealistic working conditions.

[0109] The final step is to determine the current deflection angle. Whether it is within the uniform scanning range defined by the boundary threshold. This judgment is a simple logical comparison operation: if If so, it is determined that the galvanometer is in a uniform scanning state.

[0110] if If so, it is determined that the galvanometer is in the dead zone of mechanical acceleration / deceleration transition.

[0111] Based on this judgment, the system will generate a binary scan state determination command. For example, a high-level signal is generated when the system is in a uniform scanning range; a low-level signal is generated when the system is in a mechanical acceleration / deceleration transition dead zone. This command will serve as the real-time basis for controlling the on / off state of the high-energy test beam in subsequent steps.

[0112] For example, following the aforementioned steps, the X-axis reflector of the two-dimensional mechanical scanning galvanometer is performing reciprocating scanning within the range of -0.03 radians to +0.03 radians.

[0113] The FPGA hardware main control board within the system connects to the encoder of the X-axis drive motor via a hardware interface, extracting the real-time physical position level signal output from the encoder. This encoder outputs a voltage signal... The range is from -5 volts to +5 volts, linearly corresponding to the deflection angle.

[0114] The conversion factor of the encoder was determined by consulting the equipment manual and performing calibration. 0.006 radians / volt, zero offset The value is 0. Therefore, the current deflection angle is 0. The analytical formula is: .

[0115] Next, it is necessary to set boundary thresholds to characterize the dead zone of mechanical acceleration / deceleration transitions. Based on tests of the dynamic performance of this model of galvanometer, it was found that the nonlinearity of the scanning speed exceeded the acceptable range in the 15% regions at both ends of the scanning range. The total scanning angular path is... In radians, 15% of the angular range is Radius. Therefore, the uniform scanning interval is set within the central 70% range. Lower boundary threshold. Set as Radius. Upper boundary threshold. Set as radian.

[0116] During the scanning process, the system continuously analyzes... And compare them. For example, at a certain moment, if the real-time physical position level signal output by the encoder is -4.0 volts, then the current deflection angle is... Radius. Due to The system determines that the current deflection angle is within the dead zone of mechanical acceleration / deceleration, and accordingly generates a low-level (e.g., 0 volt) scan state determination command. At another moment, if the signal is +2.5 volts, then the current deflection angle is... Radius. Due to If the system determines that the current deflection angle is within the uniform scanning range, it generates a high-level (e.g., +5 volts) scanning state determination command. This real-time generated command stream provides the basis for precise control in the next step.

[0117] S7. Receive the scanning state determination command, and perform hardware-level closed-loop control of the acousto-optic modulator according to the scanning state determination command to execute the edge truncation and conduction operation of the high-energy test beam, and obtain the target wavelength thermal radiation signal under the uniform scanning state by combining the target wavelength thermal radiation signal.

[0118] In a specific embodiment of the present invention, receiving a scanning state determination command, performing hardware-level closed-loop control on the acousto-optic modulator according to the scanning state determination command to execute the edge truncation and conduction operation of the high-energy test beam, and obtaining the target wavelength thermal radiation signal under uniform scanning state by combining the target wavelength thermal radiation signal, includes: parsing the scanning state determination command to obtain the motion state identifier of the current deflection angle, and converting the motion state identifier into a trigger level signal.

[0119] The trigger level signal is transmitted to the radio frequency drive source of the acousto-optic modulator. The radio frequency drive source changes the diffraction efficiency of the acousto-optic crystal to perform edge truncation and conduction operations on the high-energy test beam.

[0120] During the edge truncation and conduction operations, the target wavelength thermal radiation signal is recorded simultaneously, invalid signals during the edge truncation period are removed, and the target wavelength thermal radiation signal under uniform scanning state is obtained.

[0121] Specifically, this step is a crucial purification step in the entire measurement process. Its core lies in using the real-time motion state information generated in the previous step to precisely synchronize and control the energy input source, thereby physically eliminating the measurement errors introduced by the non-ideal motion of the scanning system. The entire process begins with receiving the scanning state determination command generated in step S6. This command, in the form of an electrical signal, indicates in real time whether the two-dimensional mechanical scanning galvanometer is in the uniform scanning range or the mechanical acceleration / deceleration transition dead zone.

[0122] Upon receiving the scan status determination command, the system first parses it to obtain the motion status identifier of the current deflection angle, and then converts this identifier into a trigger level signal that can directly control subsequent hardware. This step ensures the compatibility and stability of the control signal.

[0123] Next, the trigger level signal is transmitted to the radio frequency (RF) driver of the acousto-optic modulator. The acousto-optic modulator acts as a high-frequency switch in the high-energy test beam path, and its switching state is determined by the RF power provided by the RF driver. Upon receiving the trigger level signal, the RF driver changes its power output accordingly, thereby altering the intensity of the acoustic field inside the acousto-optic crystal and ultimately adjusting the beam's diffraction efficiency. This allows for the edge-truncation and conduction of the high-energy test beam. The diffraction efficiency describes the proportion of incident light energy deflected to the principal diffraction order (i.e., the beam entering subsequent optical paths), and its relationship with the RF driver power can be described by the following formula:

[0124] In the formula, It is the first-order diffraction efficiency, a dimensionless proportional value. It is the radio frequency power applied to the acousto-optic crystal, measured in watts. It is the quality factor of the acousto-optic modulator, measured in units of 1. This parameter, provided by the equipment manufacturer or obtained through experimental calibration, comprehensively reflects factors such as crystal material and transducer efficiency. It is controlled by... This allows for precise control of the optical power passing through the system. ,in It is the power of the incident high-energy test beam.

[0125] The specific control logic is as follows: When the system recognizes the trigger level signal as a low-level signal indicating the entry into the mechanical acceleration / deceleration transition dead zone, it will immediately shut off the RF power output of the RF drive source, that is, it will... By shutting off the radio frequency power output, the acousto-optic crystal loses its acoustic field. At this point, according to the formula, the diffraction efficiency... This causes the diffraction power of the high-energy test beam to drop to zero, thus performing an edge-truncation operation and physically preventing laser energy from heating the material in regions with unstable scanning speeds. Conversely, when the trigger level signal is identified as a high-level signal representing the recovery of the uniform scanning range, the system restores the RF power output of the RF drive source to a preset value, reconstructs the acoustic field of the acousto-optic crystal, restores the diffraction efficiency to its maximum value, performs a conduction operation, and allows the high-energy test beam to heat the material in regions with stable scanning speeds.

[0126] Throughout the entire process of performing the aforementioned edge truncation and conduction operations, the data acquisition system synchronously records the target wavelength thermal radiation signal output by the narrowband filtered detection channel. Because the high-energy test beam is precisely trunculated in the time domain, the portion of the original thermal radiation signal stream corresponding to the mechanical acceleration / deceleration transition dead zone will naturally decrease in signal intensity to background levels. Finally, by removing these invalid signals generated during the edge truncation period, the target wavelength thermal radiation signal under uniform scanning conditions, containing only valid data within the uniform scanning interval, can be obtained.

[0127] For example, following the aforementioned steps, the control system continues to receive scan status determination instructions from step S6, which are sequences of 0 volts (low level) or +5 volts (high level).

[0128] The system directly uses this scan status determination command as the trigger level signal. When the command is 0 volts, it is interpreted as the motion status indicator "dead zone"; when the command is +5 volts, it is interpreted as the motion status indicator "uniform speed".

[0129] The trigger level signal is sent to the radio frequency (RF) driver of the acousto-optic modulator. This driver is a TTL-level modulation type, capable of recognizing a 0-volt input as a shutdown command and a +5-volt input as a turn-on command. Upon receiving a 0-volt trigger level signal, it indicates that the two-dimensional mechanical scanning galvanometer has entered the mechanical acceleration / deceleration transition dead zone. The RF driver immediately reduces its RF power output from the preset 2 watts to 0 watts. Due to the shutdown of the RF power output, the acoustic field within the acousto-optic crystal disappears, the 10-watt high-energy test beam no longer diffracts, and its diffracted light power drops to zero, completing the edge truncation operation.

[0130] When the two-dimensional mechanical scanning galvanometer resumes its motion to the uniform scanning range, the scanning state determination command changes to +5 volts. Upon receiving this high-level signal, the RF driver immediately restores its 2-watt RF power output, reconstructs a stable acoustic wave field in the acousto-optic crystal, and performs a conduction operation, allowing the 10-watt high-energy test beam to pass through the system again.

[0131] Simultaneously, a high-speed data acquisition card, sampling at 1 MHz, synchronously records the target wavelength thermal radiation signal (a voltage signal) from the mercury cadmium telluride detector, along with the +5 volt / 0 volt scan state determination command as a timestamp. During the data processing phase, the software iterates through the acquired data, identifying and discarding any target wavelength thermal radiation signal data points recorded within the time period corresponding to a 0 volt scan state determination command. After this data cleaning, the final data sequence represents the target wavelength thermal radiation signal under uniform scanning conditions, accurately reflecting the material's response under uniform heating.

[0132] S8. Acquire the target wavelength thermal radiation signal under uniform scanning state, extract the voltage peak value of the target wavelength thermal radiation signal under uniform scanning state to obtain the transient voltage peak value, perform temperature conversion on the transient voltage peak value to generate the highest thermal coupling temperature of the vehicle lamp material under test.

[0133] In a specific embodiment of the present invention, the target wavelength thermal radiation signal under uniform scanning state is acquired, the voltage peak value of the target wavelength thermal radiation signal under uniform scanning state is extracted to obtain the transient voltage peak value, and the transient voltage peak value is converted to a temperature to generate the highest thermal coupling temperature of the vehicle lamp material under test. This includes: high-frequency sampling of the target wavelength thermal radiation signal under uniform scanning state to construct a voltage amplitude sequence that varies with time.

[0134] An extreme value search is performed on the voltage amplitude sequence to extract the maximum voltage value in the voltage amplitude sequence as the transient voltage peak.

[0135] Obtain the photoelectric conversion coefficient and system optical transmittance of a single-point infrared detector under the target filtering wavelength parameters, and construct the system transfer function by combining the photoelectric conversion coefficient and system optical transmittance.

[0136] By using the system transfer function to derive the transient voltage peak value, the actual infrared emissivity of the surface of the lamp material under test can be calculated.

[0137] The actual infrared radiant exitance is substituted into the blackbody radiation integral formula based on Planck's law for iterative solution to achieve temperature conversion and generate the highest thermal coupling temperature of the vehicle lamp material under test.

[0138] Specifically, this step is the endpoint of the entire measurement process. Its purpose is to interpret the purified electrical signal obtained in the previous steps into a key physical quantity—temperature—reached by the surface of the vehicle headlight material under test, through a rigorous physical model. The entire process begins with acquiring the target wavelength thermal radiation signal under uniform scanning conditions after purification in step S7.

[0139] First, the target wavelength thermal radiation signal under uniform scanning conditions is sampled at high frequency. This is a process of discretizing a continuous analog voltage signal into a digital sequence. By measuring at a rate much higher than the signal change frequency, a voltage amplitude sequence that can accurately reflect the instantaneous changes of the signal is constructed.

[0140] Subsequently, an extreme value search is performed on this voltage amplitude sequence. Since the heating and movement of the dynamic high-energy light spot is a dynamic process, the temperature of the material surface undergoes a rapid rise and fall, and the corresponding thermal radiation signal intensity also changes accordingly. By searching for and extracting the maximum voltage value in the voltage amplitude sequence, the transient voltage peak value can be obtained. This peak value represents the moment of most intense thermal radiation generated by the material surface due to heating during the uniform scanning process, which corresponds to the highest temperature point that can be reached.

[0141] Finally, this transient voltage peak is substituted into a temperature response model based on Planck's law for temperature transformation to generate the highest thermal coupling temperature of the tested automotive lamp material. This transformation process is not a simple linear mapping, but involves a series of rigorous physical calculations.

[0142] Obtain the photoelectric conversion coefficient of a single-point infrared detector under the target filtering wavelength parameters. unit: This coefficient is actually the product of the inherent current responsivity (A / W) of the detector's core sensing element and the signal gain (V / A) of the transimpedance amplifier (TIA) inside the detector. It represents the system-level voltage response scale of the complete detection hardware link and simultaneously obtains the system's optical transmittance. To establish the method for inferring the surface radiative exitance (unit: W / m) of the test material from the probe voltage. 2 To obtain the complete radiometric dimension chain, it is also necessary to obtain the effective radiation area formed by the high-energy test beam focusing on the material surface in step S3. (unit: Given that high-energy test beams typically exhibit a Gaussian intensity distribution, to ensure test reproducibility, the effective radiation area in this invention is uniformly reduced outwards according to the light intensity decreasing to the central peak intensity. (The boundary of the light spot cross-section at approximately 13.5% was rigorously defined and calculated), and the geometric collection efficiency calculated in step S4 was combined with this. The four components together construct the system transfer function. .

[0143] Using the constructed system transfer function, the peak transient voltage is derived in reverse to calculate the actual infrared radiant exitance of the material surface of the vehicle lamp under test. Actual infrared radiant exitance is a physical quantity representing the total energy radiated per unit time from a unit area of ​​the material within the wavelength band defined by the target filter wavelength parameters. This inverse derivation process can be expressed by the following relationship:

[0144] In the formula, It is the actual infrared emissivity of the surface of the material of the vehicle headlight under test, in watts per square meter (W / m²). ). It is the extracted transient voltage peak value, and the unit is volts (V). ). It is the system transfer function, which integrates the photoelectric conversion coefficient, the system optical transmittance, and the geometric factor of signal collection. This geometric factor is the geometric collection efficiency calculated based on Lambert's law of thermal radiation in step S4. This expresses the spatial interception ratio of radiant energy by the transmission mirror group, and its unit is volts per square meter (watts per square meter). )).

[0145] After calculating the actual infrared radiative exitance, the final step is to substitute it into the blackbody radiation integral formula based on Planck's law, and then iteratively solve for the temperature conversion. The thermal radiation of any object at a specific temperature follows Planck's law. For a real non-blackbody material, the relationship between its radiative exitance and temperature in a specific wavelength band is as follows:

[0146] In this formula, This is the absolute temperature to be determined, in Kelvin (K). ). The material of the vehicle headlight under test is at the wavelength The emissivity at that point is dimensionless. According to Kirchhoff's law of thermal radiation, the emissivity of a material in thermal equilibrium is equal to its absorptivity. Because in step S1 of this invention, the material transmittance has been specifically selected and locked to be close to zero. The intrinsic infrared absorption peak band, combined with the law of conservation of energy ,in The infrared reflectivity of the material surface in this wavelength band is typically a very small, stable constant, from which the following can be derived. This physical mechanism successfully transforms the complex and variable emissivity calibration problem across a wide spectrum into a constant-level emissivity assignment within a specific narrow band. Therefore, it is related to the material's absorption characteristics, and its value approaches 1 at the intrinsic infrared absorption peak wavelength, exhibiting excellent physical stability. In the formula... It is the radiative exitance of a blackbody at a given temperature and wavelength, as described by Planck's law of blackbody radiation. It is Planck's constant ( ), It is the speed of light ( ), It is the Boltzmann constant ( ). This is the transmittance function of the front-end filter component determined in step S2. It should be noted that, to ensure dimensional consistency, when substituting parameters such as wavelength into the above integral formula for calculation, they must be uniformly converted to the international standard unit "meter" (m). Because the equation cannot be directly solved analytically to obtain the temperature. Therefore, a numerical iteration method is adopted to continuously try different methods. Substitute the values ​​into the right side of the formula and perform integration until the result matches the previously obtained value. Matching, at this time The value represents the highest thermal coupling temperature of the final generated automotive lamp material.

[0147] For example, following the aforementioned steps, the system acquires the target wavelength thermal radiation signal of the polycarbonate vehicle lamp material under uniform scanning conditions.

[0148] The system samples the signal at a high frequency of 1 MHz, constructing a time-varying voltage amplitude sequence. By performing an extremum search on this sequence, the maximum voltage value extracted is 1.25 volts, which is the transient voltage peak value. .

[0149] Next, temperature conversion is performed. First, the system transfer function is constructed. After calibration, the overall photoelectric conversion coefficient of the used mercury cadmium telluride single-point infrared detector in the 9.60 micrometer band is... Volts / Watt. The overall system optical transmittance, taking into account the efficiency of all optical components, was determined to be 0.87. Combined with the signal collection geometry factor of approximately 0.00607, and the measurement of the high-energy test beam on the excitation surface according to... The effective radiation area calculated by boundary is The system transfer function is calculated based on the square meters. The value is .

[0150] By inversely deriving the transient voltage peak value using the system transfer function, the actual infrared emissivity of the surface material of the vehicle lamp under test can be calculated. .

[0151] Finally, this actual infrared radiative exitance is substituted into Planck's law integral formula for iterative solution. The emissivity of polycarbonate material at 9.60 micrometers is then calculated. The value was set to 0.95. This was calculated based on Kirchhoff's laws and the inherent stable infrared reflectance spectrum of approximately 5% on the polycarbonate surface, ensuring the objective accuracy of the temperature measurement results. The transmittance function of the front-end filter component... The Gaussian function is centered at 9.60 micrometers and has a half-width of 0.30 micrometers. Substituting these parameters into the integral equation:

[0152] The temperature is continuously adjusted through a numerical iterative solution algorithm. The value is calculated until the above integral result equals... The calculation results show that when the temperature The equation holds true at a temperature of 512 Kelvin. Therefore, the highest thermal coupling temperature of the final generated test vehicle lamp material is 512 Kelvin.

[0153] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined by the present invention, and all such modifications and additions should fall within the protection scope of the present invention.

Claims

1. A method for dynamic scanning and thermal coupling monitoring of high-energy light spots in automotive headlights, characterized in that, include: S1. Obtain the infrared absorption spectrum of the vehicle lamp material to be tested, perform feature analysis on the infrared absorption spectrum to extract the intrinsic infrared absorption peak wavelength where the transmittance is at a minimum, and generate the target filter wavelength parameter based on the intrinsic infrared absorption peak wavelength. S2. Receive the target filtering wavelength parameters, configure the front-end filtering component of the single-point infrared detector according to the target filtering wavelength parameters, and construct a narrowband filtering detection channel. S3. Generate a high-energy test beam. Input the high-energy test beam into a two-dimensional mechanical scanning mirror through an acousto-optic modulator. After being deflected by the two-dimensional mechanical scanning mirror, the beam is projected onto the surface of the vehicle lamp material under test to form a dynamic high-energy light spot. S4. Collect the transient thermal radiation signal excited by the dynamic high-energy light spot on the surface of the vehicle lamp material under test, and make the transient thermal radiation signal return to the two-dimensional mechanical scanning galvanometer along the incident optical path of the high-energy test beam to obtain the reverse coaxial radiation signal. S5. Obtain the reverse coaxial radiation signal, use a dichroic beam splitter to separate the reverse coaxial radiation signal and extract the infrared beam, and guide the infrared beam into the narrowband filter detection channel to obtain the target wavelength thermal radiation signal. S6. Extract the real-time physical position level signal of the two-dimensional mechanical scanning galvanometer, compare the real-time physical position level signal with the boundary threshold that characterizes the mechanical acceleration, deceleration and turning dead zone, and generate a scanning state determination command. S7. Receive scanning state determination command, perform hardware-level closed-loop control of acousto-optic modulator according to scanning state determination command to execute edge truncation and conduction operation of high-energy test beam, and obtain target wavelength thermal radiation signal under uniform scanning state by combining target wavelength thermal radiation signal. S8. Acquire the target wavelength thermal radiation signal under uniform scanning state, extract the voltage peak value of the target wavelength thermal radiation signal under uniform scanning state to obtain the transient voltage peak value, perform temperature conversion on the transient voltage peak value to generate the highest thermal coupling temperature of the vehicle lamp material under test.

2. The method for dynamic scanning and thermal coupling monitoring of high-energy light spots in automotive lamps according to claim 1, characterized in that: The process of acquiring the infrared absorption spectrum of the vehicle headlight material under test, performing feature analysis on the infrared absorption spectrum to extract the intrinsic infrared absorption peak wavelength where the transmittance is at its minimum, and generating target filtering wavelength parameters based on the intrinsic infrared absorption peak wavelength includes: The spectrometer interferogram data of the material to be tested for the vehicle lamp is obtained, and then a broadband infrared transmission data is generated by Fourier transform. Finally, the absorbance is logarithmically transformed to generate an infrared absorption spectrum. Valley search is performed on the infrared absorption spectrum to locate the spectral range with the lowest transmittance and extract the intrinsic infrared absorption peak wavelength where the transmittance is at its minimum. Extract the center wavelength and half-width of the intrinsic infrared absorption peak wavelength where the transmittance is at its minimum, and combine the center wavelength and half-width values ​​to generate the target filter wavelength parameters.

3. The method for dynamic scanning and thermal coupling monitoring of high-energy light spots in automotive headlights according to claim 1, characterized in that: The receiving of target filtering wavelength parameters, configuring the front-end filtering component of the single-point infrared detector according to the target filtering wavelength parameters, and constructing a narrowband filtering detection channel includes: Analyze the target filter wavelength parameters and extract the center wavelength and half-width values ​​of the limited infrared wavelength window; Select or adjust the front-end filter component based on the center wavelength and half-width values ​​so that the center transmission wavelength of the front-end filter component is equal to the center wavelength value, and the full width at half maximum (FWHM) of its transmission characteristics is equal to the half-width at half maximum (FWHM) value. A front-end filter component with the required transmission characteristics is installed in front of the photosensitive front of a single-point infrared detector to filter out background thermal radiation and stray light interference outside a specific wavelength range, thereby constructing a narrowband filter detection channel targeting the material's characteristic absorption peaks.

4. The method for dynamic scanning and thermal coupling monitoring of high-energy light spots in automotive lamps according to claim 1, characterized in that: The generation of the high-energy test beam involves inputting the high-energy test beam into a two-dimensional mechanical scanning mirror via an acousto-optic modulator. After being deflected by the two-dimensional mechanical scanning mirror, the beam is projected onto the surface of the vehicle headlight material under test, forming a dynamic high-energy light spot, including: A high-energy test beam with a wavelength matching the high transmittance characteristics of the automotive lamp material under test is generated and then introduced into an acousto-optic modulator. A radio frequency electrical signal is applied to the acousto-optic modulator to generate an acoustic wave field inside it. The acoustic wave field is used to diffract the incident high-energy test beam. A beam of a specific diffraction order is extracted and the beam is transmitted to a two-dimensional mechanical scanning galvanometer after passing through a dichroic beam splitter preset on the main optical axis at an incident angle corresponding to the high transmittance of the wavelength. An external control signal is input to the two-dimensional mechanical scanning galvanometer to drive its reflector surface to deflect in two dimensions. The deflected beam is then projected onto the surface of the vehicle lamp material under test through a flat-field focusing lens. The projection position is changed by combining the geometric mapping relationship between the deflection angle and the lens focal length, forming a dynamic high-energy light spot that moves on its surface according to the command.

5. The method for dynamic scanning and thermal coupling monitoring of high-energy light spots in automotive lamps according to claim 1, characterized in that: The transient thermal radiation signal excited by the dynamic high-energy light spot on the surface of the vehicle lamp material under test is collected, and the transient thermal radiation signal is reversed along the incident optical path of the high-energy test beam and returned to the two-dimensional mechanical scanning galvanometer to obtain the reverse coaxial radiation signal, including: Capture the full-band thermal radiation energy generated when a dynamic high-energy light spot moves on the surface of the automotive lamp material under test, and collect transient thermal radiation signals by spatially constraining the full-band thermal radiation energy. The transient thermal radiation signal is guided into the emitting lens group of the high-energy test beam, so that the transmission trajectory of the transient thermal radiation signal completely coincides with the transmission trajectory of the high-energy test beam to achieve reverse transmission. The reverse-transmitted transient thermal radiation signal is projected onto the reflective surface of a two-dimensional mechanical scanning galvanometer, and the reverse coaxial radiation signal is obtained by dynamically compensating for the spot displacement through the reflective surface.

6. The method for dynamic scanning and thermal coupling monitoring of high-energy light spots in automotive lamps according to claim 1, characterized in that: The process of acquiring the reverse coaxial radiation signal, using a dichroic beam splitter to separate the reverse coaxial radiation signal and extract the infrared beam, and then guiding the infrared beam into a narrowband filtered detection channel to acquire the target wavelength thermal radiation signal includes: The reverse coaxial radiation signal is received and projected onto the dielectric film surface of the dichroic beam splitter, and the wavelength selectivity of the dielectric film is used to separate the beam. The high-energy test beam in the visible light band is transmitted and the radiation energy in the infrared band is reflected. The reflected radiation energy is then extracted as the infrared band beam. The infrared beam is focused and directed into a narrowband filter detection channel. The background radiation interference other than the target filter wavelength parameter is filtered out by the front-end filter component to obtain the target wavelength thermal radiation signal.

7. The method for dynamic scanning and thermal coupling monitoring of high-energy beam spots in automotive headlights according to claim 1, characterized in that: The step involves extracting the real-time physical position level signal of the two-dimensional mechanical scanning galvanometer, comparing the real-time physical position level signal with the boundary threshold characterizing the dead zone of mechanical acceleration / deceleration, and generating a scanning state determination command, including: The drive motor encoder is connected to the two-dimensional mechanical scanning galvanometer, and the real-time physical position level signal is extracted from the drive motor encoder; The current deflection angle of the two-dimensional mechanical scanning galvanometer is obtained by analyzing the real-time physical position level signal, and the current deflection angle is compared with the boundary threshold that characterizes the dead zone of mechanical acceleration, deceleration and turning. Determine whether the current deflection angle is within the uniform scanning range defined by the boundary threshold, and generate a scanning status determination command based on the determination result.

8. The method for dynamic scanning and thermal coupling monitoring of high-energy light spots in automotive lamps according to claim 1, characterized in that: The receiving of the scanning state determination command, and the hardware-level closed-loop control of the acousto-optic modulator according to the scanning state determination command to perform edge truncation and conduction operations of the high-energy test beam, and the acquisition of the target wavelength thermal radiation signal under uniform scanning state by combining the target wavelength thermal radiation signal, including: The scanning state determination command is parsed to obtain the motion state identifier of the current deflection angle, and the motion state identifier is converted into a trigger level signal. The trigger level signal is transmitted to the radio frequency drive source of the acousto-optic modulator. The radio frequency drive source changes the diffraction efficiency of the acousto-optic crystal to perform edge truncation and conduction operations on the high-energy test beam. During the edge truncation and conduction operations, the target wavelength thermal radiation signal is recorded simultaneously, invalid signals during the edge truncation period are removed, and the target wavelength thermal radiation signal under uniform scanning state is obtained.

9. The method for dynamic scanning and thermal coupling monitoring of high-energy light spots in automotive lamps according to claim 1, characterized in that: The process of acquiring the target wavelength thermal radiation signal under uniform scanning conditions, extracting the transient voltage peak from the target wavelength thermal radiation signal under uniform scanning conditions, and performing temperature conversion on the transient voltage peak to generate the highest thermal coupling temperature of the vehicle lamp material under test includes: High-frequency sampling is performed on the target wavelength thermal radiation signal under uniform scanning conditions to construct a voltage amplitude sequence that varies with time. An extreme value search is performed on the voltage amplitude sequence to extract the maximum voltage value in the voltage amplitude sequence as the transient voltage peak value; Obtain the photoelectric conversion coefficient and system optical transmittance of a single-point infrared detector under the target filtering wavelength parameters, and construct the system transfer function by combining the photoelectric conversion coefficient and system optical transmittance. The transient voltage peak value is derived in reverse using the system transfer function, and the actual infrared emissivity of the surface of the lamp material under test is calculated. The actual infrared radiant exitance is substituted into the blackbody radiation integral formula based on Planck's law for iterative solution to achieve temperature conversion and generate the highest thermal coupling temperature of the vehicle lamp material under test.

10. The method for dynamic scanning and thermal coupling monitoring of high-energy beam spots in automotive headlights according to claim 8, characterized in that: The radio frequency (RF) drive source that transmits the trigger level signal to the acousto-optic modulator, and performs edge truncation and conduction operations on the high-energy test beam by changing the diffraction efficiency of the acousto-optic crystal through the RF drive source, includes: When the trigger level signal is identified as a low-level signal representing the transition dead zone of mechanical acceleration / deceleration, the RF power output of the RF drive source is turned off. By turning off the radio frequency power output, the acousto-optic crystal loses its acoustic field, and the diffraction power of the high-energy test beam is reduced to zero to perform an edge truncation operation. When the trigger level signal is identified as a high-level signal representing the recovery of the uniform scanning interval, the RF power output of the RF drive source is restored, and the acoustic wave field of the acousto-optic crystal is reconstructed to perform the conduction operation.

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