Method and apparatus for determining light absorption rate of light-transmissive flat member

Abstract

The present invention relates to the field of optical measurement, and provides a method and device for determining the light absorption rate of a transparent flat part for measuring the light absorption rate. The method includes: obtaining spectral data of the reflected light of the transparent flat part collected by a spectral confocal measurement system; determining the upper surface focusing peak wavelength, the upper surface focusing peak of the transparent flat part, the lower surface focusing peak wavelength, and the lower surface focusing peak of the transparent flat part according to the spectral data; determining the upper surface reflectivity corresponding to the upper surface focusing peak wavelength and the lower surface reflectivity corresponding to the lower surface focusing peak wavelength; and determining the light absorption rate of the transparent flat part according to the upper surface focusing peak, the lower surface focusing peak, the upper surface reflectivity, and the lower surface reflectivity.

Description

Technical Field

[0001] The present invention relates to the field of optical measurement, and particularly to a method and device for determining the light absorption rate of a light-transmitting flat part. Background Art

[0002] In academic research or industrial applications, it is necessary to evaluate the optical properties of materials. The light absorption rate directly reflects the absorption efficiency of materials for light energy. Existing characterization methods are limited by the indirectness of measurement methods. According to the law of conservation of light energy, the light absorption rate A = 1 - T - R. A spectrophotometer usually only directly measures the transmittance T, and the reflectance R needs to be measured by additional devices such as an integrating sphere or an ellipsometer, which increases the complexity and cost of the experiment. Especially for high-reflection materials (with metal film layers or semi-transparent materials), the error is large. For the transmission optical path of a traditional spectrophotometer for rough surfaces or strongly scattering surfaces, the transmittance will be very low. The single Lambert-Beer law only holds under the conditions of uniformity, no scattering, and low absorption. For high-absorption materials such as thick-layer silicon carbide and non-uniform porous structures, the low signal-to-noise ratio of measurement leads to calculation errors.

[0003] By characterizing the light absorption rate, the light utilization efficiency of materials and the actual light energy absorption ratio can be evaluated, and it can be used to evaluate the transparency of materials in non-contact measurement and detection.

[0004] Existing light absorption rate measurement devices are costly, large in size, relatively complex to operate, and require professional technical personnel to use. They are not suitable for rapid detection under the conditions of the processing site of light-transmitting flat parts, and it is difficult to integrate with the processing equipment of the light-transmitting flat parts to be measured. Therefore, it is impossible to detect the light absorption rate online during the processing process and is usually used for off-line detection. Summary of the Invention

[0005] In view of this, the present invention provides a method for determining the light absorption rate of a light-transmitting flat part, including:

[0006] Obtaining spectral data of the reflected light of the light-transmitting flat part collected by a spectral confocal measurement system;

[0007] Determining the upper surface focusing peak wavelength , the upper surface focusing peak and the lower surface focusing peak wavelength , the lower surface focusing peak of the light-transmitting flat part;

[0008] Determining the upper surface reflectance corresponding to the upper surface focusing peak wavelength , the lower surface reflectance corresponding to the lower surface focusing peak wavelength ;

[0009] According to the upper surface focusing peak , bottom surface focusing peak , upper surface reflectivity and the lower surface reflectivity Determining the absorbance of light-transmitting flat parts .

[0010] Optionally, determine the wavelength corresponding to the upper surface focusing peak The reflectivity of the upper surface , corresponding to the peak wavelength of the bottom surface focus The reflectivity of the lower surface ,include:

[0011] The material of the light-transmitting flat piece determines the peak wavelength corresponding to the upper surface focus. Refractive index , corresponding to the peak wavelength of the bottom surface focus Refractive index ;

[0012] Using refractive index Determine the reflectivity of the upper surface , using the refractive index Determine the reflectivity of the lower surface .

[0013] Optionally,

[0014] ;

[0015] ;

[0016] in is the refractive index of the ambient medium in the measurement environment where the optically transparent flat piece is located.

[0017] Alternatively, the absorbance of the light-transmitting flat piece can be determined as follows: :

[0018] ;

[0019] ;

[0020] ;

[0021] in Based on the peak focus on the upper surface and the lower surface focusing peak Determine the focus peak ratio, Based on the reflectivity of the upper surface and the lower surface reflectivity The influence factors of the focusing wavelength of the upper and lower surfaces on the absorbance are determined.

[0022] Optionally, in the step of determining the light absorption rate of the light-transmissive flat member further includes correcting the upper surface focusing peak and the lower surface focusing peak using the light source spectrum.

[0023] Optionally, correcting the upper surface focusing peak and the lower surface focusing peak using the light source spectrum includes:

[0024] Determining the light source intensity corresponding to the upper surface focusing peak wavelength , the light source intensity corresponding to the lower surface focusing peak wavelength in the light source spectrum;

[0025] Correcting the upper surface focusing peak using the light source intensity , and correcting the lower surface focusing peak using the light source intensity .

[0026] Optionally, the light absorption rate of the light-transmissive flat member is determined as follows :

[0027] ;

[0028] ;

[0029] ;

[0030] where is the focusing peak ratio determined according to the corrected upper surface focusing peak and the corrected lower surface focusing peak , is the influence factor of the upper and lower surface focusing wavelengths on the light absorption rate determined according to the upper surface reflectivity and the lower surface reflectivity ;

[0031] represents the result of correcting the lower surface focusing peak using the light source intensity , represents the result of correcting the upper surface focusing peak using the light source intensity .

[0032] Furthermore, after determining the light absorption rate it further includes determining the light transmittance as follows :

[0033] ;

[0034] wherein is the reflectivity pre-measured for the light-transmissive flat part.

[0035] Optionally, the spectral data is wavelength-intensity correspondence data, or pixel-intensity correspondence data, wherein the pixels correspond one-to-one with the wavelengths, and the intensity is any one of spectral illuminance, luminance, grayscale value, and light intensity.

[0036] Correspondingly, the present invention further provides an absorptance determination device for a light-transmissive flat part, including: a processor and a memory connected to the processor; wherein, the memory stores instructions executable by the processor, and the instructions are executed by the processor to enable the processor to execute the above-mentioned absorptance determination method for the light-transmissive flat part.

[0037] The technical solution provided by this application is based on the reflected light spectral data collected by a spectral confocal measurement system for a light-transmissive flat part, extracts the upper and lower surface focusing peak wavelengths, and the upper and lower surface focusing peaks, and then analyzes the absorptance of the light-transmissive flat part according to the reflectivities of the upper and lower surfaces. . The spectral confocal measurement system adopts a non-contact measurement method, can realize in-situ collection of reflected light spectral data in a wafer processing environment, and obtain the absorptance, thereby improving the flexibility of absorptance measurement, overcoming the limitations of traditional spectrophotometers in large-scale production and in-situ measurement; and the reflected light spectral data has high resolution, can provide the accuracy of the absorptance measurement result, can also meet the requirements of real-time monitoring in a modern production environment, realize rapid response, and give a certain reference to the optical properties of materials before and after processing.

[0038] The solution provided by this application does not require constructing other projection systems and optical paths. The spectral confocal measurement system can be integrated into wafer processing equipment (such as thinning machines, chemical mechanical polishing equipment, etc.), and can quickly respond and in-situ measure the absorptance of wafers in a processing environment. Measuring the absorbance by using the method provided by this application does not require the use of common transmittance measuring devices such as spectrophotometers or infrared spectrometers. The spectral confocal measurement system has a simple structure and high integration, is easier to be integrated with processing equipment, is conducive to realizing online measurement or multi-sample measurement, is not limited by the size of the sample, can reduce costs, and can realize rapid detection of material properties such as absorptance and transmittance.

[0039] According to the Lambert-Beer law, the thickness of the medium through which light passes is proportional to the light absorption rate. While measuring the thickness of the transparent flat part, its corresponding light absorption rate can be determined. By measuring the thickness and light absorption rate of transparent flat parts with different thicknesses, a corresponding relationship model between the light absorption rate and the thickness can be established. Description of the Drawings

[0040] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Figure 1 It is a flowchart of the method for determining the light absorption rate of the transparent flat part in the embodiment of the present application;

[0042] Figure 2 It is the spectral data of the reflected light collected by the spectral confocal measurement system in the embodiment of the present application;

[0043] Figure 3 It is the light source spectral data of the spectral confocal measurement system in the embodiment of the present application;

[0044] Figure 4 It is the spectral data of the demodulated reflected light in the embodiment of the present application;

[0045] Figure 5 It is the optical path schematic diagram of the transparent flat part in the embodiment of the present application. Detailed Embodiments

[0046] The following will clearly and completely describe the technical solutions of the present invention with reference to the drawings. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0047] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] The embodiment of the present invention provides a method for determining the light absorption rate of a transparent flat part. This method can be executed by an electronic device such as a computer or a server, as Figure 1 shown, this method includes the following operations:

[0049] S1. Obtain the spectral data of the reflected light of the transparent flat part collected by the spectral confocal measurement system. According to the principle of spectral confocal, for a transparent (transparent or translucent) flat part (which can be a solid or a liquid), the focusing positions are different for different wavelengths, and the focusing wavelengths are formed on both the upper and lower surfaces of the flat part. Detectors such as spectrometers receive and detect the spectral data of the reflected light of the focusing wavelengths. Figure 2 The spectral data collected at multiple different positions (the distance between the reflected light detector probe and the wafer) is shown, where the abscissa represents the wavelength of the reflected light, and the ordinate represents the light intensity. The spectral data in this solution is the light intensity corresponding to different wavelengths.

[0050] S2. Determine the upper surface focusing peak wavelength λ top 、the upper surface focusing peak I TOP (λ top ) and the lower surface focusing peak wavelength λ unter 、the lower surface focusing peak I UNTER (λ unter ) of the transparent flat part.

[0051] In some embodiments, the spectrum output by the spectrometer is data on the correspondence between wavelength and intensity, and the intensity can be any one of spectral illuminance, brightness, gray value, and light intensity. Figure 2 The curves Counts[a.u]2, Counts[a.u]3, Counts[a.u]4, and Counts[a.u]5 of four spectral data are shown, and there are two obvious peaks (characteristic peaks) in each curve. The abscissa of the first peak point in any curve is the upper surface focusing peak wavelength 、the ordinate of the first peak point is the upper surface focusing peak ; the abscissa of the second peak point is the lower surface focusing peak wavelength 、the ordinate of the second peak point is the lower surface focusing peak . For such spectra, the intensity peak and its corresponding focusing peak wavelength can be directly obtained. The intensity peak in this embodiment is specifically the peak of the light intensity.

[0052] In some embodiments, the spectrum output by the spectrometer is data on the correspondence between pixel and intensity, and the intensity can be any one of spectral illuminance, brightness, gray value, and light intensity. For such spectra, what is directly obtained is the intensity peak and its corresponding pixel. Since there is a one-to-one correspondence between the pixel and the wavelength, the corresponding wavelength can be obtained according to this correspondence. The correspondence between the pixel and the wavelength is determined through instrument calibration and calibration. For example, after factory calibration or calibration using a standard light source, the physical position of each pixel will be associated with a specific wavelength value.

[0053] S3. Determine the upper surface reflectivity R(λ top ) corresponding to the upper surface focusing peak wavelength λ top , and the lower surface reflectivity R(λ unter ) corresponding to the lower surface focusing peak wavelength λ unter .

[0054] Ideally, the material surface reflectivity can be calculated according to the formula

[0055] ;

[0056] represents the refractive index of the environmental medium where the material is located, and represents the refractive index of the material.

[0057] The refractive index is a function of the wavelength. Taking the SIC wafer as an example, its refractive index is:

[0058] ;

[0059] When the wavelength , .

[0060] Therefore, the reflectivity and the reflectivity in this embodiment are functions of the wavelength. The reflectivities for different wavelengths are different, and the values of the reflectivities are also related to the material of the transparent flat part. The specific values can be calculated using a mathematical model or queried in a database.

[0061] S4. Determine the light absorption rate ω of the transparent flat part according to the upper surface focusing peak I TOP (λ top ), the lower surface focusing peak I UNTER (λ unter ), the upper surface reflectivity R(λ top ) and the lower surface reflectivity R(λ unter ).

[0062] Furthermore, after determining the light absorption rate, the light transmittance T can be further calculated:

[0063] ;

[0064] where is the reflectivity pre-measured for the transparent flat part. For example, a single-wavelength light beam with a specific wavelength can be irradiated onto its surface, and the value of the reflectivity can be determined according to the reflected light.

[0065] Figure 5Shows the optical path schematic diagram of a transparent and light-transmitting flat part. The incident light is refracted and then reflected after reaching the lower surface of the light-transmitting flat part, and then reaches the upper surface without considering refraction loss and is detected by the spectrometer. In the optical path schematic diagram represents the incident light, represents the light reflected by the upper surface, represents the outgoing light (ignoring the further reflection on the upper surface) that returns to the detector without considering loss, represents the light refracted by the upper surface, represents the light reaching the lower surface, represents the light reflected by the lower surface;

[0066] represents the reflectivity of the upper surface of the transparent and light-transmitting flat part, represents the reflectivity of the lower surface of the transparent and light-transmitting flat part;

[0067] represents the amount of incident light absorbed by the transparent and light-transmitting flat part, represents the amount of light reflected by the lower surface absorbed by the transparent and light-transmitting flat part, represents the light absorption rate, represents the light transmittance.

[0068] According to this optical path, it can be known that:

[0069] ;

[0070] ;

[0071] where , , refer to the light intensity corresponding to in the spectrum.

[0072] Thus, the light absorption rate can be determined by using the signal intensity ratio of the focusing wavelengths on the upper and lower surfaces detected by the spectral confocal detector. The intensity ratio of the focusing wavelengths on the upper and lower surfaces is

[0073] Denote the ratio of the two peak light intensities as C

[0074] ;

[0075] Because is the upper surface focusing peak (peak light intensity) corresponding to the upper surface focusing wavelength , is the upper surface focusing peak (peak light intensity) corresponding to the lower surface focusing wavelength , so should be substituted when performing optical path analysis and calculation, and the corresponding reflectivities , , without considering internal reflection, , then

[0076] ;

[0077] From this, it can be obtained that:

[0078] ;

[0079] where

[0080] ;

[0081] ;

[0082] can be defined as the focusing peak ratio, and the influence factor of the focusing wavelengths of the upper and lower surfaces on the light absorption rate. Then, the light absorption rate can be calculated based on the focusing peak ratio and the influence factor

[0083] As a preferred embodiment, considering that the focusing wavelength peak light intensity is the characteristic reflection spectrum light intensity after being modulated by the light source spectrum, the influence of the light source spectrum needs to be removed from the upper and lower surface wavelength peak light intensity ratio, that is, the original spectrum needs to be demodulated, and the collected data spectrum can be divided by the light source spectrum. In step S4, the light source spectrum can be used to correct the upper surface focusing peak and the lower surface focusing peak .

[0084] Furthermore, using the light source spectrum to correct the upper surface focusing peak and the lower surface focusing peak includes:

[0085] Determine the light source intensity corresponding to the upper surface focusing peak wavelength and the light source intensity corresponding to the lower surface focusing peak wavelength in the light source spectrum;

[0086] Use the light source intensity to correct the upper surface focusing peak and use the light source intensity to correct the lower surface focusing peak .

[0087] Figure 3 shows the light source spectrum, where the abscissa represents the wavelength of the light source and the ordinate represents the light source intensity. The upper surface focusing peak wavelength and the lower surface focusing peak wavelength After that, the corresponding light source intensity can be obtained according to the light source spectrum. and the light source intensity .

[0088] Specifically, the peak light intensity of the focused wavelength is the characteristic reflection spectrum light intensity after being modulated by the light source spectrum. Therefore, the influence of the light source spectrum needs to be removed from the ratio of the peak light intensities of the upper and lower surfaces, that is, the original spectrum needs to be demodulated, and the collected data spectrum can be divided by the light source spectrum.

[0089] ;

[0090] represents the actually measured reflected light spectrum, represents the light source spectrum.

[0091] For the original spectrum data without removal, for the same thickness sample, there is a deviation in the ratio of the light intensities of the upper and lower surfaces, resulting in a deviation in the calculation of the absorbance.

[0092] Therefore, it is necessary to restore the unmodulated light intensity:

[0093] ;

[0094] ;

[0095] The data after correction without considering the light source spectrum characteristics, and the corrected peak light intensity ratio is

[0096] ;

[0097] Figure 4 shows the reflected light spectra after correction / demodulation for the four spectra shown in Figure 2 , that is, the curves A, B, C, and D corresponding to the spectra, where the abscissa represents the wavelength of the reflected light and the ordinate represents the light intensity. The corrected / demodulated lower surface focused peak is , and the corrected / demodulated upper surface focused peak is .

[0098] Thus, the corrected focused peak ratio can be calculated in the following way :

[0099] ;

[0100] Then

[0101] ;

[0102] where the influence factor of the focused wavelengths of the upper and lower surfaces on the absorbance :

[0103] ;

[0104] Then

[0105] ;

[0106] In one embodiment, in step S3, determining the upper surface reflectance corresponding to the upper surface focusing peak wavelength and the lower surface reflectance corresponding to the lower surface focusing peak wavelength , includes:

[0107] Determining the refractive index corresponding to the upper surface focusing peak wavelength and the refractive index corresponding to the lower surface focusing peak wavelength through the material of the transparent flat member;

[0108] Using the refractive index to determine the upper surface reflectance and using the refractive index to determine the lower surface reflectance .

[0109] According to the calculation formula of reflectance

[0110]

[0111] ;

[0112]

[0113]

[0114] where is the refractive index of the environmental medium in the measurement environment where the transparent flat member is located.

[0115] Taking a wafer as an example, the same wafer (with constant thickness) is measured, and the spectral confocal probe is used to measure the same position (the measurement point remains unchanged, and the distance from the probe changes), and the actual data obtained is processed.

[0116]

[0117] ;

[0118] Among them, the four lines of data represent the data measured and calculated at four distances. From the above data, it can be seen that at different measurement distances in the full range, for the same sample (with constant thickness), the calculation results of the absorbance remain at the same level, and the error source is related to the upper surface focusing peak​​​​​​​​​​​​​​​​​​​​​​​​ and the reading error of the lower surface focusing peak , the upper surface focusing peak wavelength and the lower surface focusing peak wavelength extraction error, and for passive devices such as dispersive lenses, the absorption of different wavelengths by each glass material causes different losses, resulting in different light intensities for each wavelength component, which in turn affects the accuracy of the focusing peak ratio value accuracy.

[0119] As a comparative example, the transmittance T = 0.137 of the wafer was measured using an existing L950 spectrophotometer, and the reflectance was 0.20. According to , the absorbance = 0.663 can be calculated, which is basically consistent with the absorbance value calculated by the method provided in this application .

[0120] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0121] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing device generate means for implementing the specified functions in Figure 1 one or more of these processes or multiple processes and / or blocks Figure 1 one or more of these blocks or multiple blocks.

[0122] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the specified functions in Figure 1 one or more of these processes or multiple processes and / or blocks Figure 1 one or more of these blocks or multiple blocks.

[0123] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions for implementing the functions specified in one process or a plurality of processes and / or blocks Figure 1 one process or a plurality of processes and / or blocks Figure 1 steps of the functions specified in one block or a plurality of blocks.

[0124] Obviously, the above embodiments are only examples for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom still fall within the protection scope of the present invention.

Claims

1. A method for determining the light absorption rate of a light-transmissive flat part, characterized in that, Comprising: Obtaining spectral data of the reflected light of a light-transmissive flat part collected by a spectral confocal measurement system; Determine the upper surface focusing peak wavelength of the transparent flat part according to the spectral data , the upper surface focusing peak and the lower surface focusing peak wavelength of the transparent flat part , the lower surface focusing peak ; Determine the upper surface reflectance corresponding to the upper surface focusing peak wavelength , the lower surface reflectance corresponding to the lower surface focusing peak wavelength ; , ; Based on the upper surface focusing peak , the lower surface focusing peak , the upper surface reflectivity and the lower surface reflectivity Determine the light absorption rate of the light-transmitting flat part : , , , in Based on the peak focus on the upper surface and the lower surface focusing peak Determine the focus peak ratio, Based on the reflectivity of the upper surface and the lower surface reflectivity The influence factors of the focusing wavelength of the upper and lower surfaces on the absorbance are determined.

2. The method according to claim 1, characterized in that Determine the upper surface reflectance corresponding to the upper surface focusing peak wavelength and the lower surface reflectance corresponding to the lower surface focusing peak wavelength including: and the lower surface reflectance corresponding to the lower surface focusing peak wavelength including: Determine the refractive index corresponding to the focusing peak wavelength of the upper surface through the material of the light-transmitting flat part and the refractive index corresponding to the focusing peak wavelength of the lower surface ; and the refractive index corresponding to the focusing peak wavelength of the lower surface ; Using the refractive index to determine the upper surface reflectance and using the refractive index to determine the lower surface reflectance .

3. The method according to claim 2, wherein: , , wherein is the refractive index of the environmental medium in the measurement environment where the light-transmissive flat member is located.

4. The method according to claim 1, wherein In the step of determining the light absorption rate of the light-transmitting flat member further includes using the light source spectrum to correct the upper surface focusing peak and the lower surface focusing peak for correction.

5. The method according to claim 4, wherein Using the light source spectrum to correct the upper surface focusing peak and the lower surface focusing peak for correction, including: Determine the light source intensity corresponding to the upper surface focusing peak wavelength in the light source spectrum ; Determine the light source intensity corresponding to the lower surface focusing peak wavelength ; ; Using the light source intensity Correct the focusing peak of the upper surface Perform correction, using the light source intensity Correct the focusing peak of the lower surface Perform correction.

6. The method according to claim 5, characterized in that, Determine the light absorption rate of the light-transmissive flat part in the following manner : , , , wherein is the focusing peak ratio determined according to the corrected upper surface focusing peak and the corrected lower surface focusing peak ; and is the influence factor of the focusing wavelength of the upper and lower surfaces on the light absorption rate determined according to the upper surface reflectivity and the lower surface reflectivity . Indicates the result of correcting the peak focusing on the lower surface using the light source intensity . Indicates the result of correcting the peak focusing on the upper surface using the light source intensity .

7. The method according to claim 1, wherein After determining the absorbance it further includes determining the transmittance in the following manner : , wherein is the reflectance pre-measured for the transparent and light-transmissive flat member 8. The method according to any one of claims 1-7, characterized in that, The spectral data is wavelength-intensity correspondence data, or pixel-intensity correspondence data, wherein the pixels correspond one-to-one with wavelengths, and the intensity is any one of spectral illuminance, brightness, gray value, and light intensity.

9. An absorbance determination device for a light-transmissive flat member, characterized in that, Comprising: A processor and a memory connected to the processor; wherein, the memory stores instructions executable by the processor, and the instructions are executed by the processor to enable the processor to execute the method for determining the light absorption rate of the light-transmissive flat part according to any one of claims 1-8.

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