Photoelectric signal measuring device and method

Abstract

The invention discloses a photoelectric signal measuring device and method, and relates to the technical field of photoelectric signal measurement. The device comprises a chopper which modulates a target light beam through a chopper plate and outputs transmission light and reflection light; the first photomultiplier and the second photomultiplier are arranged on light paths of the transmission light and the reflection light respectively and used for conducting photoelectric conversion on the transmission light and the reflection light respectively, and the first photomultiplier is located at the end, away from the chopper, of the sample table where the test sample is placed; the motor drives the chopper plate to rotate and outputs a coded value through a motor encoder; the signal processing board collects electric signals corresponding to the transmission light and the reflection light, obtains first and second reference signals according to the coding value and the number of the chopping plates, and carries out frequency mixing on the two electric signals through the first and second reference signals. And calculating the transmissivity or the reflectivity of the test sample according to the first complex signal and the second complex signal which are obtained when the test sample is not placed and the test sample is placed and obtained through frequency mixing. Therefore, the photoelectric signal measurement precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectric signal measurement, and in particular to a photoelectric signal measurement device and method. Background Art

[0002] In related art, in order to achieve photoelectric signal measurement, a photoelectric switch is used to measure the frequency of the chopper. However, the light of the photoelectric switch itself will interfere with the measurement, resulting in low accuracy of the photoelectric signal measurement. Summary of the Invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one object of the present invention is to provide a photoelectric signal measuring device to achieve high-precision measurement.

[0004] The second object of the present invention is to provide a method for measuring photoelectric signals.

[0005] To achieve the above-mentioned purpose, the first embodiment of the present invention proposes a photoelectric signal measuring device, comprising: a chopper, configured to modulate a target light beam through a chopper plate, and output transmitted light and reflected light; a first photomultiplier tube, arranged in the optical path of the transmitted light and located at an end of a sample stage away from the chopper, configured to perform photoelectric conversion on the transmitted light, wherein the sample stage is used to place a test sample; a second photomultiplier tube, arranged in the optical path of the reflected light, and configured to perform photoelectric conversion on the reflected light; a motor, configured to drive the chopper plate to rotate, and output a coding value through a motor encoder; a signal A signal processing board is configured to collect electrical signals corresponding to the transmitted light and the reflected light, and obtain a first reference signal and a second reference signal according to the coding value and the number of the chopper blades, and use the first reference signal and the second reference signal to mix the two electrical signals respectively, perform low-pass filtering on the mixed signals to obtain a first complex signal and a second complex signal, and calculate the transmittance or reflectance of the test sample based on the two groups of complex signals, wherein the two groups of complex signals include the first complex signal and the second complex signal obtained when the test sample is not placed, and the first complex signal and the second complex signal obtained when the test sample is placed.

[0006] In addition, the photoelectric signal measuring device according to the embodiment of the present invention may also have the following additional technical features: In one embodiment of the present invention, the signal processing board includes: a first acquisition module, configured to acquire a first electrical signal corresponding to the transmitted light; a second acquisition module, configured to acquire a second electrical signal corresponding to the reflected light; a processing chip, configured to obtain the first reference signal and the second reference signal according to the coding value and the number of the chopper blades, and use the first reference signal and the second reference signal to mix the first electrical signal and the second electrical signal respectively, low-pass filter the mixed signals to obtain the first complex signal and the second complex signal, and calculate the transmittance or reflectance of the test sample based on the two sets of complex signals.

[0007] In one embodiment of the present invention, the first acquisition module and the second acquisition module have the same structure, and the first acquisition module includes: a cross-group amplifier configured to convert the electrical signal corresponding to the transmitted light from a current signal into a voltage signal; and an ADC acquisition circuit configured to acquire the voltage signal to obtain the first electrical signal.

[0008] In one embodiment of the present invention, the processing chip includes: a reference signal generating module, configured to generate the first reference signal and the second reference signal according to the coding value and the number of the chopper blades; a transmitted light processing module, configured to mix the first electrical signal using the first reference signal and the second reference signal to obtain the first complex signal, and perform amplitude calculation on the first complex signal to obtain the amplitude value of the first complex signal; a reflected light processing module, configured to mix the second electrical signal using the first reference signal and the second reference signal to obtain the second complex signal, and perform amplitude calculation on the second complex signal to obtain the amplitude value of the second complex signal; and a calculation module, used to calculate the transmittance or reflectance of the test sample based on the amplitude values ​​of the first complex signal and the amplitude values ​​of the second complex signal obtained when the test sample is not placed and when the test sample is placed.

[0009] In one embodiment of the present invention, the reference signal generating module includes: a square wave signal generating unit, configured to generate a square wave signal according to the coding value; a frequency measuring unit, configured to measure the frequency of the square wave signal; and a numerically controlled oscillator, configured to generate the first reference signal and the second reference signal according to the frequency of the square wave signal.

[0010] In one embodiment of the present invention, the transmitted light processing module has the same structure as the reflected light processing module, and the transmitted light processing module includes: a bandpass filter, configured to filter out interference signals and noise other than the fundamental frequency in the first electrical signal; a mixer, configured to mix the signal output by the bandpass filter using the first reference signal and the second reference signal; a low-pass filter, configured to filter out high-frequency components in the signal output by the mixer to obtain the first complex signal; and an amplitude calculation unit, configured to perform amplitude calculation on the first complex signal to obtain the amplitude value of the first complex signal.

[0011] To achieve the above-mentioned purpose, the second embodiment of the present invention proposes a photoelectric signal measurement method, which is used for the above-mentioned photoelectric signal measurement device, and the method includes: when no test sample is placed on the sample stage, collecting the electrical signals corresponding to the transmitted light and the reflected light output by the chopper, and obtaining a first reference signal and a second reference signal according to the encoding value output by the motor encoder and the number of the chopper blades, using the first reference signal and the second reference signal to mix the two electrical signals respectively to obtain a first complex signal and a second complex signal; according to the two sets of complex signals, calculating the transmittance or reflectance of the test sample, wherein the two sets of complex signals include the first complex signal and the second complex signal obtained when the test sample is not placed, and the first complex signal and the second complex signal obtained when the test sample is placed.

[0012] In addition, the photoelectric signal measurement method according to the embodiment of the present invention may also have the following additional technical features: In one embodiment of the present invention, the first reference signal and the second reference signal are expressed by the following formula: X=cos(2×π×F2×t) Y=sin(2×π×F2×t) Wherein, X is the first reference signal, Y is the second reference signal, t is the sampling period, F2 is the frequency of the first reference signal, F2=m×F1, m is the number of the chopper blades, and F1 is the frequency of the square wave signal generated according to the encoding value.

[0013] In one embodiment of the present invention, the transmittance or the reflectance is obtained by the following formula: , Wherein, η is the transmittance or the reflectivity, R_test1 and R_test2 are the amplitude values ​​of the first complex signal when the test sample is not placed and when the test sample is placed, respectively; R_ref1 and R_ref2 are the amplitude values ​​of the second complex signal when the test sample is not placed and when the test sample is placed, respectively.

[0014] In one embodiment of the present invention, the method further includes: calculating the amplitude values ​​of multiple first complex signals, and calculating the average of the amplitude values ​​of the multiple first complex signals as the final amplitude value of the transmitted light path signal; calculating the amplitude values ​​of multiple second complex signals, and calculating the average of the amplitude values ​​of the multiple second complex signals as the final amplitude value of the reflected light path; and calculating the transmittance or reflectance of the test sample based on the final amplitude values ​​of the transmitted light path signal and the final amplitude values ​​of the reflected light path obtained when the test sample is not placed and when the test sample is placed.

[0015] According to an embodiment of the present invention, a photoelectric signal measurement device and method include: a chopper configured to modulate a target light beam through a chopper blade to output transmitted light and reflected light; a first photomultiplier tube disposed in an optical path of the transmitted light and at an end of a sample stage away from the chopper, configured to perform photoelectric conversion on the transmitted light, wherein the sample stage is used to place a test sample; a second photomultiplier tube disposed in an optical path of the reflected light and configured to perform photoelectric conversion on the reflected light; a motor configured to drive the chopper blade to rotate and output an encoding value through a motor encoder; a signal processing board configured to collect electrical signals corresponding to the transmitted light and the reflected light, and obtain a first reference signal and a second reference signal based on the encoding value and the number of chopper blades; and mixing the two electrical signals using the first reference signal and the second reference signal, respectively, performing low-pass filtering on the mixed signals to obtain a first complex signal and a second complex signal. The transmittance or reflectance of the test sample is calculated based on the two sets of complex signals, wherein the two sets of complex signals include the first complex signal and the second complex signal obtained when no test sample is placed, and the first complex signal and the second complex signal obtained when the test sample is placed. Therefore, photoelectric signal measurement can be performed without using a photoelectric switch, thereby achieving high-precision photoelectric signal measurement.

[0016] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a structural block diagram of a photoelectric signal measuring device according to an embodiment of the present invention; Figure 2 is a schematic diagram of the operation of a photoelectric signal measuring device according to a specific embodiment of the present invention; Figure 3 is a flow chart of a photoelectric signal measurement method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0019] The following describes a photoelectric signal measuring device and method according to embodiments of the present invention with reference to the accompanying drawings.

[0020] Figure 1 4 is a structural block diagram of a photoelectric signal measuring device according to an embodiment of the present invention.

[0021] like Figure 1 As shown, the photoelectric signal measuring device 100 includes: a chopper 101, configured to modulate the target light beam through a chopper plate to output transmitted light and reflected light; a first photomultiplier tube 105, arranged in the optical path of the transmitted light and located at an end of a sample stage away from the chopper 101, configured to perform photoelectric conversion on the transmitted light, wherein the sample stage is used to place a test sample; a second photomultiplier tube 106, arranged in the optical path of the reflected light, configured to perform photoelectric conversion on the reflected light; a motor 102, configured to drive the chopper plate to rotate and output an encoding value through a motor encoder; The signal processing board 127 is configured to collect electrical signals corresponding to the transmitted light and the reflected light, and obtain a first reference signal and a second reference signal based on the coding value and the number of chopper blades, and use the first reference signal and the second reference signal to mix the two electrical signals respectively, perform low-pass filtering on the mixed signals to obtain a first complex signal and a second complex signal, and calculate the transmittance or reflectance of the test sample based on the two sets of complex signals, wherein the two sets of complex signals include the first complex signal and the second complex signal obtained when the test sample is not placed, and the first complex signal and the second complex signal obtained when the test sample is placed.

[0022] Specifically, in order to achieve accurate photoelectric signal measurement, a photoelectric signal measuring device 100 is proposed. The photoelectric signal measuring device 100 includes a chopper 101 , a sample stage, a first photomultiplier tube 105 , a second photomultiplier tube 106 , a click, and a signal processing board 127 .

[0023] When photoelectric signal measurement is required, a target light beam is first emitted to the chopper 101 . The target light beam is the light beam used when measuring the test sample.

[0024] The target light beam will be directed toward the chopper 101, which includes a chopper blade. The chopper blade is integrated with the motor 102. For example, the motor 102 and the chopper blade can be set to rotate coaxially, that is, the rotating shaft of the chopper blade is fixedly connected to the rotating shaft of the motor 102, so that the rotation speed of the chopper blade is consistent with the rotation speed of the motor 102.

[0025] As the chopper blades rotate, they alternately cross the optical path of the target beam. When the blades are in the target beam's path, the target beam is reflected by the blades, and the chopper collects the reflected beam as reflected light. When the blades are not in the target beam's path, the target beam passes directly through the chopper blades, resulting in transmitted light.

[0026] After obtaining the reflected light and the transmitted light, the chopper 101 transmits the transmitted light to the first photomultiplier tube 105 and transmits the reflected light to the second photomultiplier tube 106. Because the sample stage is located in the optical path of the transmitted light, when a test sample is placed on the sample stage, the transmitted light contains information about the test sample. When no test sample is placed on the sample stage, the transmitted light does not contain information about the test sample.

[0027] The first photomultiplier tube 105 can perform photoelectric conversion on the received transmitted light to obtain an electrical signal corresponding to the transmitted light, and the second photomultiplier tube 106 can perform photoelectric conversion on the received reflected light to obtain an electrical signal corresponding to the reflected light.

[0028] Moreover, the motor 102 is configured to include a motor encoder, which can obtain the rotation speed of the motor 102 , obtain a coding value according to the rotation speed of the motor 102 , and send the coding value to the signal processing board 127 .

[0029] After obtaining the electrical signals corresponding to the transmitted and reflected light, as well as the encoding value, the signal processing board 127 calculates the transmittance or reflectance of the test sample based on the two sets of complex signals. Whether transmittance or reflectance is calculated is determined by the specific placement of the detectors, including the photomultiplier tubes, and is unrelated to the operation of the photoelectric signal measurement device 100.

[0030] The two groups of complex signals mentioned above include one group comprising the first complex signal and the second complex signal obtained when no test sample is placed, and the other group comprising the first complex signal and the second complex signal obtained when the test sample is placed.

[0031] Therefore, photoelectric signal measurement can be achieved without using a photoelectric switch, thereby achieving high-precision photoelectric signal measurement.

[0032] In some embodiments of the present invention, the signal processing board 127 includes: a first acquisition module, configured to acquire a first electrical signal corresponding to the transmitted light; a second acquisition module, configured to acquire a second electrical signal corresponding to the reflected light; a processing chip, configured to obtain a first reference signal and a second reference signal based on the coding value and the number of chopper blades, and to use the first reference signal and the second reference signal to mix the first electrical signal and the second electrical signal respectively, perform low-pass filtering on the mixed signals to obtain a first complex signal and a second complex signal, and calculate the transmittance or reflectance of the test sample based on the two sets of complex signals.

[0033] In some embodiments of the present invention, the first acquisition module has the same structure as the second acquisition module, and the first acquisition module includes: a cross-group amplifier, configured to convert the electrical signal corresponding to the transmitted light from a current signal into a voltage signal; an ADC acquisition circuit, configured to acquire the voltage signal to obtain a first electrical signal.

[0034] Therefore, by setting up cross-group amplifiers and converting the current to voltage through the transimpedance amplifier, various bandpass and low-pass filtering algorithms, signal demodulation amplitude calculations, and mean filtering can be flexibly implemented within a processing chip, with strong anti-interference capabilities, higher integration, and more flexible design.

[0035] In some embodiments of the present invention, the processing chip includes: a reference signal generating module, configured to generate a first reference signal and a second reference signal according to a coding value and the number of chopper blades; a transmitted light processing module, configured to mix a first electrical signal using the first reference signal and the second reference signal to obtain a first complex signal, and perform amplitude calculation on the first complex signal to obtain an amplitude value of the first complex signal; a reflected light processing module, configured to mix a second electrical signal using the first reference signal and the second reference signal to obtain a second complex signal, and perform amplitude calculation on the second complex signal to obtain an amplitude value of the second complex signal; and a calculation module, used to calculate the transmittance or reflectance of the test sample based on the amplitude values ​​of the first complex signal and the amplitude values ​​of the second complex signal obtained when no test sample is placed and when the test sample is placed.

[0036] In some embodiments of the present invention, the reference signal generating module includes: a square wave signal generating unit, configured to generate a square wave signal according to a coding value; a frequency measuring unit, configured to measure the frequency of the square wave signal; and a digitally controlled oscillator, configured to generate a first reference signal and a second reference signal according to the frequency of the square wave signal.

[0037] In some embodiments of the present invention, the structure of the transmitted light processing module is the same as that of the reflected light processing module. The transmitted light processing module includes: a bandpass filter configured to filter out interference signals and noise other than the fundamental frequency in the first electrical signal; a mixer configured to mix the signal output by the bandpass filter using the first reference signal and the second reference signal; a low-pass filter configured to filter out high-frequency components in the signal output by the mixer to obtain a first complex signal; and an amplitude calculation unit configured to perform amplitude calculation on the first complex signal to obtain the amplitude value of the first complex signal. The signal output by the mixer is the mixed signal.

[0038] The following combination Figure 2 The specific embodiment shown is used for description.

[0039] exist Figure 2 In the specific embodiment shown, 101 is a chopper, 104 is a sample stage, 105 is a first photomultiplier tube, 106 is a second photomultiplier tube, 107 is a cross-group amplifier, 109 is an ADC acquisition circuit, 111 is a bandpass filter, 113 is a mixer, 115 is a low-pass filter, 117 is an amplitude calculation unit, 119 is an accumulation average processing unit, 120 is a ratio calculation unit, 121 is a network port, 122 is a motor encoder, 123 is a square wave signal generating unit, 124 is a frequency measurement unit, 125 is a digitally controlled oscillator, 126 is a processing chip, and 127 is a signal processing board.

[0040] Specifically, a motor 102 with an encoder output is used. The motor 102 and the chopper blade rotate coaxially, and the motor 102 and the chopper blade rotate at a set frequency F0, that is, the motor 102 rotates F0 revolutions per second.

[0041] It should be noted that in this embodiment, since the output signal of the motor encoder 122 is incremental, it can be determined that the motor 102 and the chopper blade rotate one revolution for every increase in the encoder value N. The encoder value output by the motor encoder 122 can be set to increment by one every time the motor 102 rotates 360 / N degrees, and after the motor 102 rotates 360 degrees, the motor encoder 122 resets the output encoder value to zero and restarts counting.

[0042] The motor encoder 122 outputs an encoding value, which is input to the signal processing board 127 .

[0043] In this specific embodiment, the signal processing board 127 includes a ZYNQ chip, which is the processing chip 126 .

[0044] After the code value enters the ZYNQ chip, it first passes through square wave signal generation unit 123 within the ZYNQ chip. If the code value is less than or equal to N / 2, the square wave signal is high; otherwise, it is low. Square wave signal generation unit 123 inputs the square wave signal into frequency measurement unit 124, which measures the square wave's frequency as F1.

[0045] In this specific embodiment, the number m of chopper blades in the chopper 101 is 4, and the frequency F2 = m × F1 = 4F1 is used as the reference frequency. Based on the reference frequency F2, the IP core of the digitally controlled oscillator 125 in the ZYNQ chip generates a first reference signal X and a second reference signal Y with a frequency F2. The details are as follows: X=cos(2×π×F2×t), Y=sin(2×π×F2×t), Wherein t is a sampling period, and the sampling period t is a sampling period of the ADC acquisition circuit 109 .

[0046] When the target light beam is emitted toward the chopper 101, the target light beam passes through the chopper 101 to obtain two beams of light, namely, reflected light and transmitted light. In this specific embodiment, the target light beam is ultraviolet light.

[0047] The following description will be made by taking the transmitted light when there is a test sample on the sample stage 104 as an example.

[0048] First, the transmitted light passes through the sample stage 104 and enters the first photomultiplier tube 105, where the optical signal is converted into an electrical signal to obtain a first electrical signal. The first electrical signal is converted into a voltage signal by the cross-group amplifier 107 on the signal processing board 127, and the ADC acquisition circuit 109 is used to collect this voltage signal to obtain the first electrical signal, which is then transmitted to the ZYNQ chip.

[0049] A bandpass filter 111 is used within the ZYNQ chip. The center frequency of the passband of bandpass filter 111 is F2, which filters out interference signals and noise other than the fundamental frequency of the first electrical signal, thereby improving the signal-to-noise ratio. The signal generated by bandpass filter 111 filtering the voltage signal corresponding to the first electrical signal is signal_t.

[0050] The above signal signal_t ​​can be expressed as follows: , Among them, A is the electrical signal amplitude of signal signal_t, is the phase deviation.

[0051] The mixer 113 mixes the first reference signal X and the second reference signal Y with the signal signal_t, and then passes through the low-pass filter 115 to filter out high-frequency components to obtain signals X1 and Y1. The filtered high-frequency components include high-frequency signals twice F2 and above.

[0052] The signals X1 and Y1 obtained by low-pass filtering the mixed signals can be expressed as follows:

[0053] After obtaining signals X1 and Y1, the first complex signal Z = X1 + iY1 when the test sample is placed can be obtained based on signals X1 and Y1. The amplitude value of the complex signal is calculated as follows:

[0054] Wherein, R is the amplitude value of the complex signal. When the test sample is placed on the sample stage 104 , if the complex signal is the first complex signal Z, then R is the amplitude value R_test1 of the first complex signal Z. If the complex signal is the second complex signal, then R is the amplitude value R_ref1 of the second complex signal.

[0055] After obtaining the first complex signal Z when the test sample is placed, the amplitude calculation unit 117 can be used to calculate the amplitude value R_test1 of the first complex signal Z when the test sample is placed, that is, the amplitude value R_test1 of the first complex signal when the test sample is placed.

[0056] Because the first acquisition module and the second acquisition module have the same structure, and the transmitted light processing module and the reflected light processing module have the same structure, the processing of reflected light when the test sample is placed on the sample stage 104 can be referred to the processing of transmitted light described above, the only difference being that reflected light, rather than transmitted light, is processed, and that the second photomultiplier tube 106 is used. In this case, the amplitude value R_ref1 of the second complex signal when the test sample is placed can be obtained.

[0057] Furthermore, the transmitted light when no test sample is placed on the sample stage 104 is obtained. The processing of the transmitted light when no test sample is placed on the sample stage 104 is consistent with the processing flow of the transmitted light when a test sample is placed on the above-mentioned sample stage 104. At this time, the amplitude value R_test2 of the first complex signal when no test sample is placed can be obtained.

[0058] The processing of the reflected light when no test sample is placed on the sample stage 104 is consistent with the processing flow of the reflected light when a test sample is placed on the sample stage 104 . In this case, the amplitude value R_ref2 of the second complex signal when no test sample is placed can be obtained.

[0059] After obtaining R_test1, R_ref1, R_test2, and R_ref2, the ratio calculation unit 120 can obtain the transmittance or reflectance of the test sample according to the following formula: : .

[0060] The transmittance or reflectance is calculated by the ratio calculation unit 120 After that, the calculated transmittance or reflectance can be sent to the network port 121. Upload to the host computer.

[0061] Optionally, after obtaining R_test1, R_ref1, R_test2, and R_ref2, the cumulative averaging processing unit 119 may be started to perform cumulative averaging processing on R_test1, R_ref1, R_test2, and R_ref2 to further reduce the measurement error. Then, the cumulative averaging result is: , , , , in, is the cumulative average of the amplitude values ​​of the first complex signal when the test sample is placed, is the cumulative average of the amplitude values ​​of the second complex signal when the test sample is placed, is the cumulative average of the amplitude values ​​of the first complex signal when no test sample is placed, is the cumulative average of the amplitude values ​​of the second complex signal when no test sample is placed, M is the number of accumulation points, that is, M measurements are performed, and after M amplitude values ​​are obtained, the cumulative average is performed. is the amplitude value of the first complex signal when the test sample is placed obtained in the i-th measurement, is the amplitude value of the second complex signal when the test sample is placed, obtained by the i-th measurement, is the amplitude value of the first complex signal obtained in the i-th measurement when no test sample is placed, is the amplitude value of the second complex signal obtained in the i-th measurement when no test sample is placed.

[0062] That is to say, after obtaining M R_test1, the M R_test1 can be cumulatively averaged according to the above formula to obtain , and after obtaining M R_ref1, perform cumulative averaging on the M R_ref1 according to the above, and obtain After obtaining M R_test1, the M R_test2 are accumulated and averaged according to the above formula to obtain , and after obtaining M R_ref2, perform cumulative averaging on the M R_ref2 according to the above, and obtain .

[0063] above That is the final amplitude value of the transmitted light path signal when the test sample is placed. This is the final amplitude value of the reflected light path when the test sample is placed. That is the final amplitude value of the transmitted light path signal when no test sample is placed. This is the final amplitude value of the reflected light path when no test sample is placed.

[0064] At this time, the transmittance or reflectance of the test sample calculated by the ratio calculation unit 120 is for: .

[0065] In summary, the photoelectric signal measuring device of an embodiment of the present invention includes: a chopper configured to modulate a target light beam through a chopper blade to output transmitted light and reflected light; a first photomultiplier tube disposed in the optical path of the transmitted light and located at an end of a sample stage away from the chopper, configured to perform photoelectric conversion on the transmitted light, wherein the sample stage is used to place a test sample; a second photomultiplier tube disposed in the optical path of the reflected light and configured to perform photoelectric conversion on the reflected light; a motor configured to drive the chopper blade to rotate and output a coding value through a motor encoder; a signal processing board configured to collect electrical signals corresponding to the transmitted light and the reflected light, and obtain a first reference signal and a second reference signal based on the coding value and the number of chopper blades, and use the first reference signal and the second reference signal to mix the two electrical signals respectively, perform low-pass filtering on the mixed signals to obtain a first complex signal and a second complex signal, and calculate the transmittance or reflectance of the test sample based on the two sets of complex signals, wherein the two sets of complex signals include the first complex signal and the second complex signal obtained when no test sample is placed, and the first complex signal and the second complex signal obtained when the test sample is placed. Therefore, photoelectric signal measurement can be performed without using a photoelectric switch, thereby achieving high-precision photoelectric signal measurement.

[0066] Furthermore, the present invention provides a photoelectric signal measurement method.

[0067] Figure 3 is a flow chart of a photoelectric signal measurement method according to an embodiment of the present invention.

[0068] In an embodiment of the present invention, the photoelectric signal measurement method is used in the photoelectric signal measurement device of the above embodiment.

[0069] like Figure 3 As shown, the photoelectric signal measurement method includes: S11, when no test sample is placed on the sample stage, collect the electrical signals corresponding to the transmitted light and the reflected light output by the chopper, and obtain a first reference signal and a second reference signal according to the encoding value output by the motor encoder and the number of chopper blades, and use the first reference signal and the second reference signal to mix the two electrical signals respectively to obtain a first complex signal and a second complex signal.

[0070] S12, calculating the transmittance or reflectance of the test sample based on the two sets of complex signals, wherein the two sets of complex signals include the first complex signal and the second complex signal obtained when the test sample is not placed and the first complex signal and the second complex signal obtained when the test sample is placed.

[0071] In some embodiments of the present invention, the first reference signal and the second reference signal are expressed by the following formula: X=cos(2×π×F2×t), Y=sin(2×π×F2×t), Wherein, X is the first reference signal, Y is the second reference signal, t is the sampling period, F2 is the frequency of the first reference signal, F2 = m × F1, m is the number of chopper blades, and F1 is the frequency of the square wave signal generated according to the code value.

[0072] In some embodiments of the present invention, the transmittance or reflectance is obtained by the following formula: , Wherein, η is the transmittance or reflectance, R_test1 and R_test2 are the amplitude values ​​of the first complex signal when the test sample is not placed and when the test sample is placed, respectively; R_ref1 and R_ref2 are the amplitude values ​​of the second complex signal when the test sample is not placed and when the test sample is placed, respectively.

[0073] In some embodiments of the present invention, the photoelectric signal measurement method also includes: calculating the amplitude values ​​of multiple first complex signals, and calculating the average of the amplitude values ​​of the multiple first complex signals as the final amplitude value of the transmitted light path signal; calculating the amplitude values ​​of multiple second complex signals, and calculating the average of the amplitude values ​​of the multiple second complex signals as the final amplitude value of the reflected light path; calculating the transmittance or reflectance of the test sample based on the final amplitude value of the transmitted light path signal and the final amplitude value of the reflected light path obtained when the test sample is not placed and when the test sample is placed.

[0074] It should be noted that for other specific implementations of the photoelectric signal measurement method according to the embodiment of the present invention, reference may be made to the photoelectric signal measurement device according to the above embodiment.

[0075] The photoelectric signal measurement method of the embodiment of the present invention can realize photoelectric signal measurement without using a photoelectric switch, thereby achieving high-precision photoelectric signal measurement.

[0076] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0077] It should be understood that various components of the present invention may be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods may be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof may be used: a discrete logic circuit having logic gate circuits for implementing logic functions on data signals, an application-specific integrated circuit having suitable combinational logic gate circuits, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc.

[0078] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0079] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0081] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0082] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0083] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A photoelectric signal measuring device, characterized in that: include: a chopper configured to modulate the target light beam through a chopper plate and output transmitted light and reflected light; a first photomultiplier tube, disposed in the optical path of the transmitted light and located at an end of a sample stage away from the chopper, configured to perform photoelectric conversion on the transmitted light, wherein the sample stage is used to place a test sample; a second photomultiplier tube, disposed on an optical path of the reflected light and configured to perform photoelectric conversion on the reflected light; a motor configured to drive the chopper blade to rotate and output a code value through a motor encoder; A signal processing board is configured to collect electrical signals corresponding to the transmitted light and the reflected light, and obtain a first reference signal and a second reference signal based on the coding value and the number of the chopper blades, and use the first reference signal and the second reference signal to mix the two electrical signals respectively, perform low-pass filtering on the mixed signals to obtain a first complex signal and a second complex signal, and calculate the transmittance or reflectance of the test sample based on the two sets of complex signals, wherein the two sets of complex signals include the first complex signal and the second complex signal obtained when the test sample is not placed, and the first complex signal and the second complex signal obtained when the test sample is placed.

2. The photoelectric signal measuring device according to claim 1, characterized in that: The signal processing board includes: a first acquisition module, configured to acquire a first electrical signal corresponding to the transmitted light; a second acquisition module, configured to acquire a second electrical signal corresponding to the reflected light; The processing chip is configured to obtain the first reference signal and the second reference signal according to the coding value and the number of the chopper blades, and use the first reference signal and the second reference signal to mix the first electrical signal and the second electrical signal respectively, perform low-pass filtering on the mixed signals to obtain the first complex signal and the second complex signal, and calculate the transmittance or reflectance of the test sample based on the two sets of complex signals.

3. The photoelectric signal measuring device according to claim 2, characterized in that: The first acquisition module has the same structure as the second acquisition module, and the first acquisition module includes: a cross-group amplifier configured to convert the electrical signal corresponding to the transmitted light from a current signal to a voltage signal; The ADC acquisition circuit is configured to acquire the voltage signal to obtain the first electrical signal.

4. The photoelectric signal measuring device according to claim 2, characterized in that: The processing chip includes: a reference signal generating module, configured to generate the first reference signal and the second reference signal according to the code value and the number of the chopper blades; a transmitted light processing module, configured to mix the first electrical signal using the first reference signal and the second reference signal to obtain the first complex signal, and perform amplitude calculation on the first complex signal to obtain an amplitude value of the first complex signal; a reflected light processing module, configured to mix the second electrical signal using the first reference signal and the second reference signal to obtain the second complex signal, and perform amplitude calculation on the second complex signal to obtain an amplitude value of the second complex signal; The calculation module is used to calculate the transmittance or reflectance of the test sample according to the amplitude value of the first complex signal and the amplitude value of the second complex signal obtained when the test sample is not placed and when the test sample is placed.

5. The photoelectric signal measuring device according to claim 4, characterized in that: The reference signal generating module includes: a square wave signal generating unit, configured to generate a square wave signal according to the code value; a frequency measuring unit, configured to measure the frequency of the square wave signal; The digitally controlled oscillator is configured to generate the first reference signal and the second reference signal according to the frequency of the square wave signal.

6. The photoelectric signal measuring device according to claim 4, characterized in that: The structure of the transmitted light processing module is the same as that of the reflected light processing module, and the transmitted light processing module includes: a bandpass filter configured to filter out interference signals and noise other than a fundamental frequency in the first electrical signal; a mixer configured to mix the signal output by the bandpass filter using the first reference signal and the second reference signal; a low-pass filter configured to filter out high-frequency components in the signal output by the mixer to obtain the first complex signal; The amplitude calculation unit is configured to perform amplitude calculation on the first complex signal to obtain an amplitude value of the first complex signal.

7. A photoelectric signal measurement method, characterized in that: For use in a photoelectric signal measuring device according to any one of claims 1 to 6, the method comprising: When no test sample is placed on the sample stage, respectively, electrical signals corresponding to the transmitted light and the reflected light output by the chopper are collected, and a first reference signal and a second reference signal are obtained according to a code value output by the motor encoder and the number of the chopper blades, and the first reference signal and the second reference signal are used to mix the two electrical signals to obtain a first complex signal and a second complex signal; The transmittance or reflectance of the test sample is calculated based on two sets of complex signals, wherein the two sets of complex signals include a first complex signal and a second complex signal obtained when the test sample is not placed, and a first complex signal and a second complex signal obtained when the test sample is placed.

8. The photoelectric signal measurement method according to claim 7, characterized in that: The first reference signal and the second reference signal are expressed by the following formula: X=cos(2×π×F2×t) Y=sin(2×π×F2×t) Wherein, X is the first reference signal, Y is the second reference signal, t is the sampling period, F2 is the frequency of the first reference signal, F2=m×F1, m is the number of the chopper blades, and F1 is the frequency of the square wave signal generated according to the encoding value.

9. The photoelectric signal measurement method according to claim 7, characterized in that: The transmittance or the reflectance is obtained by the following formula: ， Wherein, η is the transmittance or the reflectivity, R_test1 and R_test2 are the amplitude values ​​of the first complex signal when the test sample is not placed and when the test sample is placed, respectively; R_ref1 and R_ref2 are the amplitude values ​​of the second complex signal when the test sample is not placed and when the test sample is placed, respectively.

10. The photoelectric signal measurement method according to claim 7, characterized in that: The method further comprises: Calculating amplitude values ​​of a plurality of first complex signals, and calculating an average value of the amplitude values ​​of the plurality of first complex signals as a final amplitude value of the transmitted light path signal; Calculating amplitude values ​​of a plurality of second complex signals, and calculating an average value of the amplitude values ​​of the plurality of second complex signals as a final amplitude value of the reflected light path; The transmittance or reflectance of the test sample is calculated according to the final amplitude value of the transmission light path signal and the final amplitude value of the reflection light path obtained when the test sample is not placed and when the test sample is placed.

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