CN106296970B - Detection system and detection method of thin film - Google Patents

Detection system and detection method of thin film Download PDF

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Publication number
CN106296970B
CN106296970B CN201610657275.1A CN201610657275A CN106296970B CN 106296970 B CN106296970 B CN 106296970B CN 201610657275 A CN201610657275 A CN 201610657275A CN 106296970 B CN106296970 B CN 106296970B
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magnetic
thickness
detection
detection unit
unit
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CN106296970A (en
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戚务昌
林永辉
张凯
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Weihai Hualing Opto Electronics Co Ltd
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Weihai Hualing Opto Electronics Co Ltd
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    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
    • G07D7/12—Visible light, infrared or ultraviolet radiation
    • G07D7/128—Viewing devices
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/04—Testing magnetic properties of the materials thereof, e.g. by detection of magnetic imprint
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/16—Testing the dimensions
    • G07D7/164—Thickness

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  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Control Or Security For Electrophotography (AREA)
  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)

Abstract

The application provides a detection system and a detection method of a thin film. The detection system comprises a multifunctional sensor, an analog-to-digital conversion unit and a control unit, wherein the multifunctional sensor comprises three detection units, namely an optical detection unit, a magnetic detection unit and a thickness detection unit, and the three detection units are used for respectively carrying out optical detection, magnetic detection and thickness detection on each scanning point on a film to be detected; the input end of the analog-to-digital conversion unit is electrically connected with the output end of the optical detection unit, the output end of the magnetic detection unit and the output end of the thickness detection unit, and the analog-to-digital conversion unit is used for converting output signals of the three detection units into corresponding digital signals respectively; the control unit is electrically connected with the multifunctional sensor and the analog-to-digital conversion unit and is used for controlling the multifunctional sensor and the analog-to-digital conversion unit to work. The inspection system can simultaneously inspect three physical quantities of the film and enables the inspection system to produce images of different physical properties at the same resolution.

Description

Detection system and detection method of thin film
Technical Field
The application relates to the field of detection of thin films, in particular to a detection system and a detection method of a thin film.
Background
In the financial field, a currency detector, an ATM (automatic teller machine) and a sorter mainly identify and screen the authenticity of paper money in three modes, namely an optical mode, a magnetic mode and a thickness mode, the three modes correspond to the three modes, the paper money is separately detected by an optical image sensor, a magnetic detection device and a thickness detection device on the market at present, and due to the difference of physical quantities detected in the three modes and the difference of detection methods, output data types and formats obtained by the three modes are different, so that a processing device for the output data is relatively complex; in addition, the three physical quantities have different corresponding detection resolutions, so that the three detected physical quantity data have no corresponding relation, and subsequent identification and screening are not facilitated.
Therefore, there is a need for an inspection system and method that can simultaneously generate three inspection images of thin film with the same resolution.
Disclosure of Invention
The present disclosure provides a system and a method for detecting a thin film, so as to generate three thin film detection images with the same resolution.
In order to achieve the above object, according to one aspect of the present application, there is provided an inspection system of a thin film, the inspection system including: the multifunctional sensor comprises three detection units, namely an optical detection unit, a magnetic detection unit and a thickness detection unit, wherein the three detection units are used for respectively carrying out optical detection, magnetic detection and thickness detection on each scanning point on a film to be detected; the input end of the analog-to-digital conversion unit is electrically connected with the output end of the optical detection unit, the output end of the magnetic detection unit and the output end of the thickness detection unit, and the analog-to-digital conversion unit is used for converting the output signals of the three detection units into corresponding digital signals respectively; and the control unit is electrically connected with the multifunctional sensor and the analog-to-digital conversion unit and is used for controlling the multifunctional sensor and the analog-to-digital conversion unit to work.
Further, the above detection system further comprises: and the input end of the correction unit is electrically connected with the output end of the analog-to-digital conversion unit, the control end of the correction unit is electrically connected with the control unit, and the correction unit is used for correcting the digital signal output by the analog-to-digital conversion unit.
Further, the correction unit includes: a correction coefficient acquisition module electrically connected to an output end of the analog-to-digital conversion unit, the correction coefficient acquisition module being configured to acquire a correction coefficient of each detection unit corresponding to each scanning point; and the calculation module is electrically connected with the correction coefficient acquisition module, corrects each digital signal output by the analog-to-digital conversion unit by adopting each correction coefficient, and the correction coefficients correspond to the digital signals output by the analog-to-digital conversion unit when the film to be detected is detected one by one.
Further, the correction coefficient obtaining module includes: an initial data obtaining module, configured to obtain initial data of each scanning point of each detection unit, where the initial data includes first initial data and second initial data, and the first initial data of the optical detection unit is optical first initial data L1MNThe second initial data of the optical detection unit isOptical second initial data L2MNThe first initial data of the magnetism detection unit is magnetic first initial data M1MNThe second initial data of the magnetic detection unit is magnetic second initial data M2MNThe first initial data of the thickness detection unit is first initial thickness data T1MNThe second initial data of the thickness detection unit is second initial thickness data T2MNWherein M and N represent the row number and the column number of each scanning point, respectively, and when the light source of the optical detection unit does not emit light, the digital signal corresponding to the optical detection data of each scanning point output by the analog-to-digital conversion unit is the optical first initial data L1MNWhen the light source emits light, after scanning the optical sample film at the focal point of the optical detection unit, the digital signal corresponding to the optical detection data of each scanning point output by the analog-to-digital conversion unit is the optical second initial data L2MNThe optical sample film is a blank paper without characters and images, and after the magnetic detection unit scans the magnetic sample film, the minimum digital signal corresponding to the magnetic detection data at each scanning point output by the analog-to-digital conversion unit is the magnetic first initial data M1MNAfter the magnetic detection unit scans the magnetic sample thin film, the maximum digital signal corresponding to the magnetic detection data at each scanning point output by the analog-to-digital conversion unit is the magnetic second initial data M2MNThe surface of the magnetic sample film is provided with a plurality of rectangular magnetic strips at intervals, and when no film is placed on the multifunctional sensor, the digital signal corresponding to the thickness detection data output by the analog-to-digital conversion unit is the first initial thickness data T1MNAfter the thickness detection unit scans the thickness sample film, the digital signal corresponding to the thickness detection data of each scanning point output by the analog-to-digital conversion unit is the second initial data T of the thickness detection unit2MNThe thickness sample film is a film with uniform thickness; a correction coefficient calculation module using formula K1MNPredetermined gray value/(L)2MN-L1MN) Calculating to obtain the optical correction coefficientK1MNBy the formula K2MNPredetermined gray value/(M)2MN-M1MN) Calculating to obtain the magnetic correction coefficient K2MNBy the formula K3MNPredetermined gray value/(T)2MN-T1MN) Calculating to obtain thickness correction coefficient K3MN。
Further, the calculating module includes: optical computing module using formula (L)MN-L1MN)×K1MNFor the above LMNPerforming a correction, wherein L isMNAfter the optical detection unit scans the film to be detected, the analog-to-digital conversion unit outputs digital signals corresponding to the optical detection data of each scanning point; magnetic computing module, using formula (M)MN-M1MN)×K2MNFor the above MMNPerforming a correction, wherein M isMNAfter the magnetic detection unit scans the film to be detected, the analog-to-digital conversion unit outputs digital signals corresponding to the magnetic detection data of the scanning points; thickness calculation module using formula (T)MN-T1MN)×K3MNOr (T)MN-T1MN)+TSFor the above-mentioned TMNCorrecting, wherein T isMNAfter the film to be measured is scanned by the thickness detection unit, the digital signal corresponding to the thickness detection data of each scanning point output by the analog-to-digital conversion unit is TSAre offset gray scale values.
Further, the above detection system comprises: and a storage unit electrically connected to the correction unit and the control unit, for storing the correction coefficient and the initial data.
Further, the above detection system further comprises: and a digital-to-analog conversion unit electrically connected to the magnetic detection unit, the thickness detection unit, the storage unit, and the control unit, wherein the digital-to-analog conversion unit is configured to convert a digital signal corresponding to the corrected magnetic reference voltage into a voltage signal and input the voltage signal to the magnetic detection unit, and the digital-to-analog conversion unit is configured to convert a digital signal corresponding to the corrected thickness reference voltage into a voltage signal and input the voltage signal to the thickness detection unit, wherein the corrected magnetic reference voltage is used to correct a signal output when the magnetic detection unit detects the magnetic reference voltage, and the corrected thickness reference voltage is used to correct a signal output when the thickness detection unit detects the thickness reference voltage.
Further, the correction unit further includes: a magnetic reference voltage correction module using formula MRMMN＝MM+(MM-MMMN) Calculating the digital signal M corresponding to the corrected magnetic reference voltageRMMNWherein, M is as defined aboveMIs a magnetic reference voltage VMCorresponding digital signal, above MMMNThe magnetic detection voltage V of each scanning point is detected when no film is placedMMNA corresponding digital signal; thickness reference voltage correction module using formula TRTMN＝TT+(TT-T1MN) Calculating the corrected thickness reference voltage TRTMNWherein, T isTIs a thickness reference voltage VTCorresponding digital signal, said T1MNThe first initial data of thickness is the thickness detection voltage V of each scanning point when no film is placed on the multifunctional sensor1MNA corresponding digital signal.
According to another aspect of the present application, there is provided an inspection method of a thin film, the inspection method including: step S1, using three detecting units of the multifunctional sensor to respectively perform optical detection, magnetic detection and thickness detection on each scanning point on the film to be detected, wherein the three detecting units are respectively an optical detecting unit, a magnetic detecting unit and a thickness detecting unit; and step S2, converting the output signals of the three detection units into corresponding digital signals respectively.
Further, the detection method further comprises: in step S3, the digital signal obtained in step S2 is corrected.
Further, before the step S3, the detecting method further includes: step a is to acquire a correction coefficient for each detection unit corresponding to each scanning point, the correction coefficient being used to correct the digital signal acquired in step S2.
Further, the step a includes: step A1, obtaining the initial data of each detection unit, the initial data includes optical first initial data L1MNOptical second initial data L2MNMagnetic first initial data M1MNMagnetic second initial data M2MNFirst initial data T of thickness1MNSecond initial data T of thickness2MNWherein M and N represent the row number and the column number of the scanning point, respectively, and when the light source of the optical detection unit does not emit light, the digital signal obtained by performing analog-to-digital conversion on the optical detection data output by the optical detection unit is the optical first initial data L1MNWhen the light source emits light, after scanning the optical sample film at the focal point of the optical detection unit, the digital signal obtained by analog-to-digital converting the optical detection data at each scanning point is the optical second initial data L2MNAfter the magnetic detection unit scans the magnetic sample film, the minimum digital signal of the magnetic detection data at each scanning point after analog-to-digital conversion is the magnetic first initial data M1MNAfter the magnetic sample film is scanned by the magnetic detection unit, the maximum digital signal obtained by a/d conversion of the magnetic detection data at each scanning point is the magnetic second initial data M2MNWhen no film is placed on the multifunctional sensor, the digital signal of the thickness detection data output by the thickness detection unit after the analog-to-digital conversion is the first initial thickness data T1MNWhen the thickness detection unit scans the thickness sample film, the digital signal obtained by performing analog-to-digital conversion on the thickness detection data of each scanning point is the second initial data T of the thickness detection unit2MN(ii) a Step A2, calculating the correction coefficient by using the initial data, and using formula K1MNPredetermined gray value/(L)2MN-L1MN) Calculating to obtain the optical correction coefficient K1MNBy the formula K2MNPredetermined gray value/(M)2MN-M1MN) Calculating to obtain the magnetic correction coefficient K2MNBy the formula K3MNPredetermined gray value/(T)2MN-T1MN) Calculating to obtain thickness correction coefficient K3MN。
Further, the step S3 includes: using the formula (L)MN-L1MN)×K1MNFor the above LMNPerforming a correction, wherein L isMNAfter the optical detection unit scans the film to be detected, digital signals corresponding to the optical detection data of the scanning points are output after analog-to-digital conversion; using the formula (M)MN-M1MN)×K2MNFor the above MMNPerforming a correction, wherein M isMNAfter the magnetic detection unit scans the film to be detected, digital signals corresponding to the magnetic detection data of the scanning points are output after analog-to-digital conversion; using the formula (T)MN-T1MN)×K3MNOr (T)MN-T1MN)+TSFor the above-mentioned TMNCorrecting, wherein T isMNA digital signal corresponding to the thickness detection data of each scanning point is output after the thickness detection unit scans the film to be detected and performs analog-to-digital conversion, wherein T isSAre offset gray scale values.
Further, the detection method further comprises: and storing the correction coefficient and the initial data.
Further, before the step S1, the detection method further includes: correcting a magnetic reference voltage and inputting the corrected magnetic reference voltage into the magnetic detection unit, wherein the corrected magnetic reference voltage corrects a signal output when the magnetic detection unit detects the magnetic reference voltage; the thickness reference voltage is corrected and inputted to the thickness detection means, and the corrected thickness reference voltage corrects a signal outputted when the thickness detection means detects the thickness.
Further, the above-mentioned process of correcting the magnetic reference voltage includes: the magnetic reference voltage V is input to the magnetic detection unitM(ii) a When the multifunctional sensor is not provided with any film, the magnetic detection unit is started and outputs a plurality of magnetic detection voltages VMMN(ii) a The above V is mixedMAnd the above VMMNRespectively rotateConversion into digital signal MMAnd MMMNBy the formula MRMMN＝MM+(MM-MMMN) Calculating the digital signal M corresponding to the corrected magnetic reference voltageRMMN(ii) a Mixing the above MRMMNConverted into a voltage signal VRMMNThe process of correcting the thickness reference voltage includes: inputting the thickness reference voltage V to the thickness detection unitT(ii) a When the multifunctional sensor is not provided with any film, the thickness detection unit is started and outputs a plurality of thickness detection voltages V1MN(ii) a The above V is mixedTAnd the above V1MNRespectively converted into digital signals TTAnd T1MNBy the formula TRTMN＝TT+(TT-T1MN) Calculating the corrected digital signal T corresponding to the thickness reference voltageRTMN(ii) a Mixing the above TRTMNConverted into a voltage signal VRTMN。
By applying the technical scheme, the three detection units in the multifunctional sensor controlled by the control unit in the detection system can simultaneously detect three physical quantities of the film, the analog-to-digital conversion unit carries out similar data processing on the three physical quantities, the data processing hardware device is simplified, and the detection system can generate images with the same resolution and different physical characteristics.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application. In the drawings:
FIG. 1 illustrates a schematic structural diagram of a detection system provided in accordance with an exemplary embodiment of the present application;
FIG. 2 illustrates a schematic structural diagram of a detection system provided by an embodiment of the present application;
FIG. 3 is a schematic diagram illustrating a detection system according to yet another embodiment of the present application; and
fig. 4 shows a schematic structural diagram of a detection system provided in another embodiment of the present application.
Wherein the figures include the following reference numerals:
1. a multifunctional sensor; 2. an analog-to-digital conversion unit; 3. a correction unit; 4. a control unit; 5. a storage unit; 6. a digital-to-analog conversion unit.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
As described in the background art, three film images with the same resolution are obtained simultaneously, and the application provides a film detection system and a film detection method.
In a typical embodiment of the present application, a film detection system is provided, as shown in fig. 1, the film detection system includes a multifunctional sensor 1, an analog-to-digital conversion unit 2, and a control unit 4, wherein the multifunctional sensor includes three detection units, namely an optical detection unit, a magnetic detection unit, and a thickness detection unit, and the three detection units are used for respectively performing optical detection, magnetic detection, and thickness detection on each scanning point on a film to be detected; the input end of the analog-to-digital conversion unit 2 is electrically connected with the output end of the optical detection unit, the output end of the magnetic detection unit and the output end of the thickness detection unit, and the analog-to-digital conversion unit 2 is used for converting the output signals of the three detection units into corresponding digital signals respectively; the control unit 4 is electrically connected to the multifunctional sensor 1 and the analog-to-digital conversion unit 2, and is configured to control the multifunctional sensor 1 and the analog-to-digital conversion unit 2 to operate.
The three detection units in the multifunctional sensor controlled by the control unit in the detection system enable the three detection units to detect three physical quantities of the film simultaneously, the analog-to-digital conversion unit performs similar data processing on the three physical quantities, a data processing hardware device is simplified, and the detection system can generate images with the same resolution and different physical characteristics.
The multifunctional sensor comprises an optical detection unit, a magnetic detection unit and a thickness detection unit which are arranged on the same substrate.
The optical detection unit comprises an optical lens, a light source on the side surface of the optical lens, a transparent plate arranged above the optical lens, a circuit board arranged below the optical lens and at least one row of photoelectric conversion chips, wherein the photoelectric conversion chips are arranged on the circuit board and positioned right below the optical lens, a row of light sensing windows are arranged on the surface of each photoelectric conversion chip, and the photoelectric conversion chips are used for sensing light by the light sensing windows and converting optical signals into electric signals.
The magnetism detecting unit comprises a permanent magnet arranged in a common frame body, a circuit substrate, a signal processing chip and at least one row of magnetism sensing chips arranged on the upper surface of the circuit substrate, wherein the circuit substrate, the signal processing chip and the at least one row of magnetism sensing chips are arranged above the permanent magnet, the signal processing chip comprises a shift logic transmission function and a differential amplification function, and nonmagnetic protective plates are arranged above the magnetism sensing chips on the upper surface of the circuit substrate and the signal processing chip. When the magnetic original passes through the magnetic sensing chip, the magnetoresistance of the magnetic sensing chip changes, so that the voltage output of the magnetic sensing chip changes.
The thickness detection unit comprises a circuit substrate, at least one row of induction charge chips arranged on the circuit substrate and a common electrode arranged on the circuit substrate, wherein the circuit substrate, the at least one row of induction charge chips and the common electrode are arranged in a common frame body. The length of the common electrode corresponds to the total length of at least one row of induction charge chips, and protection plates are arranged above the common electrode and the row of induction charge chips. When the original passes over the induction charge chip, the dielectric constant between the induction charge chip and the common electrode changes, the quantity of charges induced by the induction charge chip changes, and therefore the voltage output of the induction charge chip changes.
The number of photoelectric conversion chips in the optical detection unit, the number of magnetic induction chips in the magnetic detection unit and the number of induced charge chips in the thickness detection unit in the multifunctional sensor are all the same, and the interval between adjacent photoelectric conversion chips, the interval between magnetic induction chips in adjacent magnetic detection units and the interval between adjacent induced charge chips are all the same, i.e. the photoelectric conversion chips, the magnetic induction chips and the photoelectric conversion chips are in one-to-one correspondence, so that the resolutions of the three detection units are the same, and the outputs of the three detection units are all voltages and the output formats are the same.
The analog-to-digital conversion unit in the present application may include one analog-to-digital converter, or may include a plurality of analog-to-digital converters, where each analog-to-digital converter may be a parallel analog-to-digital converter, or may be a serial analog-to-digital converter. A person skilled in the art can select a suitable analog-to-digital converter according to the specific situation.
The resolution of each analog-to-digital converter is at least 8 bits, so that the detected analog electrical signal can be converted into a total of 256 discrete values from at least 0 to 255. The skilled person can select an analog-to-digital converter with a suitable resolution according to the actual situation.
In order to make the data obtained by the detection system and the finally obtained image more real and accurate, as shown in fig. 2, the detection system preferably further includes a correction unit 3, an input end of the correction unit 3 is electrically connected to an output end of the analog-to-digital conversion unit, a control end of the correction unit is electrically connected to the control unit, and the correction unit is configured to correct the digital signal output by the analog-to-digital conversion unit.
The correction unit may be any processor in the prior art, such as an ARM, DSP or FPGA. The person skilled in the art can select a suitable processor as the correction unit according to the actual situation.
In another embodiment of the present application, the correction unit includes a correction coefficient obtaining module and a calculating module, wherein the correction coefficient obtaining module is electrically connected to an output end of the analog-to-digital converting unit, and the correction coefficient obtaining module is configured to obtain a correction coefficient of each of the detecting units corresponding to each of the scanning points; the calculation module is electrically connected with the correction coefficient acquisition module, corrects each digital signal output by the analog-to-digital conversion unit by using each correction coefficient, and the correction coefficients correspond to the digital signals output by the analog-to-digital conversion unit when the film to be detected is detected one by one.
In yet another embodiment of the present application, the correction coefficient obtaining module includes an initial data obtaining module and a correction coefficient calculating module, wherein the initial data obtaining module is configured to obtain initial data of each scanning point of each of the detecting units, the initial data includes first initial data and second initial data, and the first initial data of the optical detecting unit is optical first initial data L1MNThe second initial data of the optical detection unit is optical second initial data L2MNThe first initial data of the magnetism detection unit is magnetic first initial data M1MNThe second initial data of the magnetic detection unit is magnetic second initial data M2MNThe first initial data of the thickness detection unit is first initial thickness data T1MNThe second initial data of the thickness detection unit is second initial thickness data T2MNWherein, M and N represent the row number and the column number of each scanning point respectively.
The correction coefficient calculation module adopts a formula K1MNPredetermined gray value/(L)2MN-L1MN) Calculating to obtain the optical correction coefficient K1MNBy the formula K2MNPredetermined gray value/(M)2MN-M1MN) Calculating to obtain the magnetic correction coefficient K2MNBy the formula K3MNPredetermined gray value/(T)2MN-T1MN) Calculating to obtain thickness correction coefficient K3MN。
The skilled person can select a suitable predetermined gray value according to the actual situation.
In a preferred embodiment of the present application, when the resolution of the analog-to-digital converter is 8 bits, the predetermined gray scale value is any number between 50 and 255.
Wherein, when the light source of the optical detection unit does not emit light, after the optical detection unit is started, the digital signal corresponding to the optical detection data of each scanning point output by the analog-to-digital conversion unit is the optical first initial data L1MNWhen the light source emits light, after the optical detection unit scans the optical sample film at the focal point, the digital signal corresponding to the optical detection data of each scanning point output by the analog-to-digital conversion unit is the optical second initial data L2MN. The optical sample film is white paper without characters and images.
After the magnetic detection unit scans the magnetic sample film, the minimum digital signal corresponding to the magnetic detection data of each scanning point output by the analog-to-digital conversion unit is the magnetic first initial data M1MNAfter the magnetic detection unit scans the magnetic sample thin film, the maximum digital signal corresponding to the magnetic detection data at each scanning point output by the analog-to-digital conversion unit is the magnetic second initial data M2MN. The surface of the magnetic sample film is provided with a plurality of rectangular magnetic strips at intervals.
When the multifunctional sensor is not provided with any film, the thickness detection unit is started to scan, and the digital signal which is output by the analog-to-digital conversion unit and corresponds to the thickness detection data of each scanning point is the first initial thickness data T1MNAfter the thickness detection unit scans the thickness sample film, the digital signal corresponding to the thickness detection data of each scanning point output by the analog-to-digital conversion unit is the second initial data T of the thickness detection unit2MNThe thickness sample film is a film having a uniform thickness.
In order to correct the detection data output by the three detection units of the multifunctional sensor more accurately, the calculation module comprises: the device comprises an optical calculation module, a magnetic calculation module and a thickness calculation module.
The optical computing module adopts a formula (L)MN-L1MN)×K1MNFor the above LMNPerforming a correction, wherein L isMNAfter the optical detection unit scans the film to be detected, the analog-to-digital conversion unit outputs digital signals corresponding to optical detection data of the scanning points.
The magnetic calculation module adopts a formula (M)MN-M1MN)×K2MNFor the above MMNPerforming a correction, wherein M isMNAfter the film to be measured is scanned by the magnetic detection unit, the analog-to-digital conversion unit outputs a digital signal corresponding to the magnetic detection data of each scanning point.
The thickness calculation module adopts a formula (T)MN-T1MN)×K3MNOr (T)MN-T1MN)+TSFor the above-mentioned TMNCorrecting, wherein T isMNAnd after the film to be detected is scanned by the thickness detection unit, the analog-to-digital conversion unit outputs a digital signal corresponding to the thickness detection data of each scanning point. Due to TMN-T1MNThe result may be negative, which is difficult to display in the image, and therefore, in order to more accurately display the test result, the offset gray value T is usedSThe calculation result is increased so that the calculation result is greater than 0.
One is that when the multifunctional sensor is not provided with any film to be detected, the voltage output by the thickness detection unit is about 0V, and at this time, the thickness calculation module adopts (T)MN-T1MN)×K3MNFor the above-mentioned TMNCorrecting, when the multifunctional sensor is not placed with any film to be detected, the voltage output by the thickness detection unit is about VDD/2, and the thickness calculation module adopts a formula (T)MN-T1MN)+TSFor the above-mentioned TMNCorrecting the above TSIs a shift of the gray value, which is related to the thickness characteristic of the test film, andand the value is set according to actual needs and is used for improving the calculation result.
General TSBetween 50 and 200. Those skilled in the art can set the appropriate T according to the actual situationSThe value is obtained.
In another embodiment of the present application, as shown in fig. 3, the detection system includes a storage unit 5, and the storage unit 5 is electrically connected to the correction unit 3 and the control unit 4, and is used for storing the correction coefficient and the initial data. When the detection data after analog-to-digital conversion needs to be corrected by the correction coefficient and the initial data, the storage unit 5 inputs the stored initial data and correction coefficient to the correction unit 3.
The above-mentioned storage unit may be any one of the memories in the prior art that can implement the storage function of the present application, and those skilled in the art can select a suitable memory as the storage unit according to practical situations, for example, an EEPROM memory or a FLASH memory can be selected.
In order to make the reference voltages of the magnetic detection unit and the thickness detection unit correct, even when each scanning point of the magnetic detection unit does not have any thin film placed on the multifunction sensor, the outputs of the respective magnetic-sensitive chips of the magnetic detection unit are made equal to the same voltage value, while the outputs of the respective induced charge chips of the thickness detection unit are made equal to the same voltage value. As shown in fig. 4, it is preferable that the detection system further includes a digital-to-analog conversion unit 6, the digital-to-analog conversion unit 6 is electrically connected to the magnetic detection unit, the thickness detection unit, and the control unit 4, the digital-to-analog conversion unit 6 is configured to convert a digital signal corresponding to the corrected magnetic reference voltage into a voltage signal and input the voltage signal to the magnetic detection unit, and the digital-to-analog conversion unit 6 is configured to convert a digital signal corresponding to the corrected thickness reference voltage into a voltage signal and input the voltage signal to the thickness detection unit, wherein the corrected magnetic reference voltage is used to correct a signal output when the magnetic detection unit detects the magnetic signal, and the corrected thickness reference voltage is used to correct a signal output when the thickness detection unit detects the thickness signal.
The digital-to-analog conversion unit in the present application may include one digital-to-analog converter, or may include a plurality of digital-to-analog converters, and each digital-to-analog converter may be a parallel digital-to-analog converter, or may be a serial digital-to-analog converter. One skilled in the art can select an appropriate digital-to-analog converter depending on the particular situation.
The resolution of each digital-to-analog converter is at least 8 bits, so that the detected analog electrical signal can be converted into a total of 256 discrete values from at least 0 to 255. The skilled person can select a suitable digital-to-analog converter according to the actual situation.
In another embodiment of the present application, the correction unit further includes a magnetic reference voltage correction module and a thickness reference voltage correction module.
Wherein the magnetic reference voltage correction module adopts a formula MRMMN＝MM+(MM-MMMN) Calculating the digital signal M corresponding to the corrected magnetic reference voltageRMMNWherein, M is as defined aboveMIs a magnetic reference voltage VMCorresponding digital signal, above MMMNThe magnetic detection voltage V of each scanning point is detected when no film is placedMMNA corresponding digital signal.
The thickness reference voltage correction module adopts a formula TRMN＝TT+(TT-T1MN) Calculating the corrected thickness reference voltage TRTMNWherein, T isTIs a thickness reference voltage VTCorresponding digital signal, said T1MNIs first initial data of thickness, the first initial data T of thickness1MNThe thickness of each scanning point is detected by voltage V when no film is placed1MNA corresponding digital signal.
The thickness reference voltage correction module is suitable for outputting a voltage V corresponding to first initial data1MNA thickness detection unit at about VDD/2.
In another exemplary embodiment of the present application, a method for inspecting a thin film is provided, the method including: step S1, using three detecting units of the multifunctional sensor to respectively perform optical detection, magnetic detection and thickness detection on each scanning point on the film to be detected, wherein the three detecting units are respectively an optical detecting unit, a magnetic detecting unit and a thickness detecting unit; and step S2, converting the output signals of the three detection units into corresponding digital signals respectively.
The detection method can simultaneously detect three physical quantities of the film, and the analog-to-digital conversion unit performs similar data processing on the three physical quantities, so that a data processing hardware device is simplified, and the detection system can generate images with the same resolution and different physical characteristics.
In order to obtain a more accurate detection image, the detection method preferably further includes: in step S3, the digital signal obtained in step S2 is corrected.
In another embodiment of the present application, before the step S3, the detecting method further includes: step a, obtaining a correction coefficient of each detection unit corresponding to each scanning point, where the correction coefficient is used to correct the digital signal obtained in step S2, and each optical detection data of each scanning point of the film to be detected corresponds to one correction coefficient, each magnetic detection data corresponds to one correction coefficient, and each thickness detection data corresponds to one correction coefficient, that is, each scanning point corresponds to three correction coefficients. The correction coefficient of the optical detection unit corrects detection data obtained by scanning the corresponding scanning point by the optical detection unit, the correction coefficient of the magnetic detection unit corrects detection data obtained by scanning the corresponding scanning point by the magnetic detection unit, and the correction coefficient of the thickness detection unit corrects detection data obtained by scanning the corresponding scanning point by the thickness detection unit.
In order to correct the detected data more efficiently, in an embodiment of the present application, the step a includes: step A1, obtaining initial data of each detection unit, wherein the initial data comprises optical first initial data L1MNOptical second initial data L2MNMagnetic first initial data M1MNMagnetic second initial data M2MNFirst initial data T of thickness1MNSecond initial data T of thickness2MNWherein, M and N represent the row ordinal number and the column ordinal number of the scanning point respectively; step A2, calculating the correction coefficient by using the initial data, and using formula K1MNPredetermined gray value/(L)2MN-L1MN) Calculating to obtain the optical correction coefficient K1MNBy the formula K2MNPredetermined gray value/(M)2MN-M1MN) Calculating to obtain the magnetic correction coefficient K2MNBy the formula K3MNPredetermined gray value/(T)2MN-T1MN) Calculating to obtain thickness correction coefficient K3MN。
The predetermined gray scale value may take any number between 0 and 255. The skilled person can select a suitable predetermined gray value according to the actual situation.
In a preferred embodiment of the present application, when the resolution of the analog-to-digital converter is 8 bits, the predetermined gray scale value is any number between 50 and 255.
When the light source of the optical detection unit does not emit light, the optical detection unit is started to perform blank scanning to obtain optical detection data, each photoelectric conversion chip detects one optical detection data, the optical detection data are subjected to analog-to-digital conversion to obtain corresponding digital signals, and the digital signals are the optical first initial data L1MNThe optical second initial data L2MNWhen the light source emits light, after scanning the optical sample film at the focal point of the optical detection unit, the optical detection data (i.e., the optical detection data detected by each photoelectric conversion chip) at each scanning point is converted into a digital signal by analog-to-digital conversion.
After the magnetic detection unit scans the magnetic sample film, the minimum digital signal of the magnetic detection data at each scanning point after analog-to-digital conversion is the magnetic first initial data M1MN(ii) a After the magnetic detection unit scans the magnetic sample film, each magnetic sensing chip of the magnetic detection unit outputs magnetic detection data, and the maximum digital signal of the magnetic detection data of each scanning point after analog-to-digital conversion is the magnetic second initial numberAccording to M2MN。
When the multifunctional sensor is not placed in the detection film, the thickness detection unit is started, each induction charge chip outputs thickness detection data, and the digital signal of the thickness detection data of each scanning point after analog-to-digital conversion is the first initial thickness data T1MNWhen the thickness detection unit scans the thickness sample film, the digital signal obtained by performing analog-to-digital conversion on the thickness detection data corresponding to each scanning point obtained by each induced charge chip is the second initial data T of the thickness detection unit2MN。
The step S3 includes: using the formula (L)MN-L1MN)×K1MNFor the above LMNCorrecting, wherein after the optical detection unit scans the film to be detected, each photoelectric conversion chip outputs an optical detection data corresponding to each detection electrode, and the optical detection data are subjected to analog-to-digital conversion and then output corresponding digital signals as LMN(ii) a Using the formula (M)MN-M1MN)×K2MNFor the above MMNCorrecting, wherein after the magnetic detection unit scans the film to be detected, each magnetic sensing chip outputs a magnetic detection data corresponding to each detection electrode, and the magnetic detection data are subjected to analog-to-digital conversion to output corresponding digital signals as the MMN(ii) a Using the formula (T)MN-T1MN)×K3MNOr (T)MN-T1MN)+TSFor the above-mentioned TMNCorrecting, wherein after the thickness detection unit scans the film to be detected, each inductive charge chip outputs thickness detection data corresponding to each scanning point, and a digital signal obtained by performing analog-to-digital conversion on the thickness detection data is recorded as TMN. T aboveSAre offset gray scale values.
In order to more efficiently correct the detection data, the present application preferably further includes: and storing the correction coefficient and the initial data. The stored data can be accessed at any time.
In another embodiment of the present application, before the step S1, the detecting method further includes: correcting a magnetic reference voltage and inputting the corrected magnetic reference voltage into the magnetic detection unit, wherein the corrected magnetic reference voltage corrects a signal output when the magnetic detection unit detects the magnetic reference voltage; the thickness reference voltage is corrected and inputted to the thickness detection means, and the corrected thickness reference voltage corrects a signal outputted when the thickness detection means detects the thickness.
The magnetic reference voltage is a desired voltage set according to actual needs when no object is detected, and is usually half of the power supply voltage.
The thickness reference voltage is a desired voltage set according to actual needs when no object is detected, and is usually half of the power supply voltage, or slightly higher than 0V.
In another embodiment of the present application, the step of correcting the magnetic reference voltage includes: the magnetic reference voltage V is input to the magnetic detection unitM(ii) a When the multifunctional sensor is not provided with any detection film, the magnetic detection unit is started and outputs a plurality of magnetic detection voltages VMMN(ii) a The above V is mixedMAnd the above VMMNRespectively converted into digital signals MMAnd MMMNUsing formula MRMMN＝MM+(MM-MMMN) Calculating the digital signal M corresponding to the corrected magnetic reference voltageRMMN(ii) a Mixing the above MRMMNConverted into a voltage signal VRMMN。
The process of correcting the thickness reference voltage includes: inputting the thickness reference voltage V to the thickness detecting unitT(ii) a When the multifunctional sensor is not provided with any film, the thickness detection unit is started and outputs a plurality of thickness detection voltages V1MN(ii) a The above V is mixedTAnd the above V1MNRespectively converted into digital signals TTAnd T1MNBy the formula TRTMN＝TT+(TT-T1MN) Calculating the corrected digital signal T corresponding to the thickness reference voltageRMN。
In order to make the technical solutions of the present application more clearly understood by those skilled in the art, the solutions of the present application will be described below with reference to specific embodiments.
Example 1
Fig. 3 is a block diagram showing a configuration of a detection system in which the multifunction sensor 1 includes an optical detection unit, a magnetic detection unit, and a thickness detection unit. The resolution of each of the three detection units is 100DPI, each of the three detection units has only one row of detection chips (the detection chip in the optical detection unit is a photoelectric conversion chip, the detection chip in the magnetic detection unit is a magnetic sensing chip, and the detection chip in the thickness detection unit is an induced charge chip), and the number of the detection chips in one row of the three detection units is 720.
The control unit 4 controls the three detection units to have the same clock frequency, wherein the light source of the optical detection unit is monochromatic. The analog-to-digital conversion unit 2 is a three-input end 8-bit parallel analog-to-digital converter, the three input ends are respectively and electrically connected with the output ends of the optical detection unit, the magnetic detection unit and the thickness detection unit, and the analog-to-digital converter is used for simultaneously converting output signals of the three detection units into digital signals.
The correction unit 3 is implemented by an FPGA and includes a correction coefficient acquisition module and a calculation module, the correction coefficient acquisition module is used for calculating a correction coefficient, and the calculation module is used for calculating corrected detection data. The correction coefficient acquisition module comprises an initial data acquisition module and a correction coefficient calculation module. The calculation module comprises an optical calculation module, a magnetic calculation module and a thickness calculation module. The storage unit is realized by an EEPROM and is used for storing correction data and correction coefficients of each detection chip of the three detection units. The control unit is also realized by FPGA and is used for controlling all units to work cooperatively.
The working flow of the detection system of the film is as follows:
firstly, an initial data acquisition module and a calculation module in a correction unit are used for acquiring a correction coefficient.
For the optical detection unit, the control unit 4 controls the optical detection unit of the multi-function sensor 1 to perform optical detection with the light source thereof turned offThe measuring unit scans a line to obtain a line of data, and the line of data is converted into an 8-bit digital signal by the analog-to-digital conversion unit 2, wherein the digital signal is optical first initial data L11N(L1MNM in (1) is thus L11NWhere N is 1,2, … …, 720), the initial data acquisition module acquires the optical first initial data L11N。
A white reference original (optical sample film) is placed at the focal point of the optical detection unit, the control unit 4 controls the light source to be turned on and then scans a line to obtain the optical detection data of the scanning point, and then the optical detection data is subjected to analog-to-digital conversion into a digital signal, wherein the digital signal is the optical second initial data L21N(L2MNM in (1) is thus L21NWhere N is 1,2, … …, 720), the initial data acquisition module acquires optical second initial data L21N。
The correction unit 3 adopts a formula K11N＝217/(L21N-L11N) Calculating the optical correction coefficient K corresponding to each detection chip of the optical detection unit11NIs a reaction of K11NAnd L11NIs stored in the storage unit 5.
For the magnetic detection unit, the control unit 4 controls the magnetic detection unit of the multifunctional sensor 1 to dynamically scan the magnetic sample film (on which a certain width of magnetic ink is printed) to obtain magnetic detection data, and converts the magnetic detection data into digital signals by using the analog-to-digital conversion unit, and the correction unit 3 calculates the maximum digital signal and the minimum digital signal of each detection chip in the scanning process, wherein the minimum digital signal is the magnetic first initial data M11NThe maximum digital signal is magnetic second initial data M21N。
Using the formula K2MN＝217/(M21N-M11N) Calculating to obtain the magnetic correction coefficient K21NIs a reaction of K21NAnd M11NIs stored in the storage unit 5.
For the thickness detection unit, when the detection film does not exist, the control unit 4 controls the thickness detection unit to scan a line of data to obtain thickness detection data, and the thickness detection data is converted into thickness detection data by adopting the analog-to-digital conversion unitDigital signals as first initial data T of thickness11N。
Placing a thickness sample film on a detection system, scanning the film to obtain a line of thickness detection data, and converting the thickness detection data into digital signals, wherein the digital signals are called thickness second initial data T21N。
The correction coefficient calculation module adopts a formula K31N＝217/(T21N-T11N) Calculating to obtain a thickness correction coefficient K31NAfter the calculation is finished, the first initial data T is used11NAnd K31NTo be stored in the storage unit 5.
And secondly, performing thickness detection, optical detection and magnetic detection on the film to be detected by adopting three detection units in the multifunctional sensor.
The object to be detected is placed in the detection system, the control unit 4 controls the three detection units of the multifunctional sensor to scan the object to be detected simultaneously, and the three detection units sequentially output 720 data of respective lines under the driving of clock signals. Taking the detection data of the first detection chip of each detection unit as an example, the optical detection data (corresponding to the optical detection data of one scanning point) of the first detection chip of the optical detection unit, the magnetic detection data of the first detection chip of the magnetic detection unit, and the thickness detection data of the first detection chip of the thickness detection unit are simultaneously output to the analog-to-digital conversion unit 2 under the driving of one clock, the analog-to-digital conversion unit 2 converts the three data into digital signals, and the digital signal corresponding to the optical detection data of the first detection chip of the optical detection unit is marked as L11And the digital signal corresponding to the magnetic detection data of the first detection chip in the magnetic detection unit is recorded as M11And the digital signal corresponding to the thickness detection data of the first detection chip of the thickness detection unit is recorded as T11。
And finally, a correction unit is adopted to correct the digital signal output by the analog-digital conversion unit.
The digital signals corresponding to the three kinds of detection data are transmitted to the correction unit, and each time the computer is started (the power supply of the system is turned on), the correction unit 3 reads out the three detection units from the storage unit 5The first initial data and correction coefficient corresponding to each detection chip are expressed by formula (L)11-L111)×K111For the above L11The correction is performed by using the formula (M)11-M131)×K211For the above M11The correction is performed by using the formula (T)11-T131)×K311For the above-mentioned T11And (6) correcting.
The above-mentioned process is repeated until the 720 th clock, the correction unit 3 completes the calculation of the corrected data corresponding to each of the three detection units, i.e. the corrected data of the optical detection unit is (L)MN-L1MN)×K1MNCorrected data (M) of the magnetic detecting unitMN-M1MN)×K2MNThe corrected data of the thickness detection unit is (T)MN-T1MN)×K3MNThus, a plurality of rows are scanned continuously, and a luminance image representing three physical quantities can be generated, wherein M is the row number of the scanning point, and N is the column number of the scanning point.
Example 2
The difference from embodiment 1 is that the number of light sources of the optical detection unit is 5, which are red light, green light, blue light, infrared light and ultraviolet light, respectively, and the clock frequency of the optical detection unit is 5 times that of the magnetic detection unit. The clock frequencies of the magnetic detection unit and the thickness detection unit are the same.
Due to different clock frequencies, the analog-to-digital conversion unit consists of two analog-to-digital converters, the input end of the one-way analog-to-digital converter is electrically connected with the output end of the optical detection unit, and the two input ends of the two-way analog-to-digital converter are respectively electrically connected with the output ends of the magnetic detection unit and the thickness detection unit. Here, the light source of the optical detection unit is 5, that is, 5 lights are respectively turned on for the same scanning point for 5 times of scanning, and since the clock frequency of the optical detection unit is 5 times of that of the thickness detection unit, that is, the time required for the optical detection unit to sequentially scan one line by 5 lights is the same as the time required for the thickness detection unit to scan one line. The data processing method of the magnetic detection unit and the thickness detection unit in this embodiment is the same as that in embodiment 1, and is not described herein again.
The following mainly describes lightAnd (5) data processing flow of the optical detection unit. When the optical detection unit is compensated, the control unit 4 controls the light source of the optical detection unit of the multifunctional sensor 1 to be not on, the optical detection unit scans a line in an idle mode to obtain a line of data, the line of data is converted into an 8-bit digital signal by the analog-to-digital conversion unit 2, and the digital signal is optical first initial data L11N(L1MNM in (1) is thus L11NWhere N is 1,2, … …, 720), the initial data acquisition module acquires the optical first initial data L11N。
Then, a white reference original (optical sample film) is placed at the focal point of the optical detection unit, the control unit 4 controls the light source to light red light and scan one line to obtain optical detection data of a scanning point, and the optical detection data is subjected to analog-to-digital conversion into a digital signal, wherein the digital signal is red light optical second initial data L21NR(L2MNRM in (1) is thus L21NRWhere N is 1,2, … …, 720, and the last letter in the subscript represents a different light source, in this process, since the light source is red light, denoted by "R"), the initial data acquisition module acquires red-light optical secondary initial data L21NR。
Using the formula K11NR＝217/(L21NR-L11N) Calculating the optical correction coefficient K of red light11NR。
The above-mentioned process is repeated until the 720 th clock, and the correction unit 3 completes the calculation of the corrected data corresponding to each of the three detection units.
Placing a white reference manuscript (optical sample film) at the focal position of the optical detection unit, controlling the light source to light the green light by the control unit 4, scanning a line to obtain the optical detection data of the scanning point, and performing analog-to-digital conversion on the optical detection data to obtain a digital signal, wherein the digital signal is the green light optical second initial data L21NR(L2MNGM in (1) is thus L21NGWhere N is 1,2, … …, 720, and the last letter in the subscript represents a different light source, in this process, since the light source is green light, denoted by "G"), the initial data acquisition module acquires green optical secondary initial data L21NG. Using the formula K11NG＝217/(L21NG-L11N) And (4) calculating.
The blue light optical correction coefficient K is obtained by the same method11NBInfrared optical correction coefficient K11NIRAnd ultraviolet light optical correction coefficient K11NP. All the correction coefficients and the first initial data are stored in a storage unit.
When the film to be detected is scanned, the control unit controls the magnetic detection unit and the thickness detection unit in the multifunctional sensor simultaneously, and independently controls the optical detection unit, the analog-to-digital conversion unit corresponding to the optical detection unit and the subsequent processing circuit, so that the optical detection unit and the analog-to-digital conversion unit can work under a faster clock reference. The magnetic detection unit or the thickness detection unit scans a line of data, the corresponding optical detection unit scans a line of data respectively for red light, green light, blue light, infrared light and ultraviolet light, and the data converted by the digital conversion unit are respectively a digital signal to L corresponding to the red light optical detection data of the scanning pointMNRDigital signal L corresponding to green light optical detection dataMNGDigital signal L corresponding to infrared optical detection dataMNIRDigital signal L corresponding to blue light optical detection dataMNBAnd digital signal corresponding to ultraviolet optical detection data to LMNP. Using the formula (L)MNR-L1MN)×K1MNRTo LMNIRThe correction is performed by using the formula (L)MNG-L1MN)×K1MNGTo L is paired withMNIGThe correction is performed by using the formula (L)MNB-L1MN)×K1MNBTo LMNIBThe correction is performed by using the formula (L)MNIR-L1MN)×K1MNIRTo LMNIIRThe correction is performed by using the formula (L)MNP-L1MN)×K1MNPTo LMNIPAnd (6) correcting.
Thus, 5 images corresponding to 5 kinds of light of the optical detection unit, 1 image of the magnetic detection unit and 1 image of the thickness detection unit can be obtained by continuously scanning a plurality of lines.
Example 3
The difference from embodiment 2 is that the clock frequency of the optical detection unit in the multifunctional sensor is the same as that of the magnetic detection unit and the thickness detection unit, but the optical detection unit outputs five paths, and one five-path analog-to-digital converter corresponds to the optical detection unit. The optical detection unit outputs 5 paths of color light, so that the time required for scanning 5 color light is the same as the time required for scanning one line by the magnetic detection unit and the thickness detection unit, and the five paths of analog-to-digital converters output the conversion data to the correction unit 3 at a higher speed for correction, and the respective correction and data processing modes are the same as those of embodiment 2, which is not described herein again.
Example 4
The structural block diagram of the detection system is shown in fig. 4, and the difference from embodiment 3 is that a digital-to-analog conversion unit 6 is added, and the main function is to correct the reference voltage of each scanning point of the magnetic detection unit and the thickness detection unit in the multifunctional sensor, and reduce the deviation caused by the discreteness between the scanning points. The correction unit further comprises a magnetic reference voltage correction module and a thickness voltage correction module.
The digital-to-analog conversion unit is provided with two 8-bit digital-to-analog converters, one digital-to-analog converter is electrically connected with the magnetic detection unit, and the other digital-to-analog converter is electrically connected with the thickness detection unit. The correction process of the reference voltage of each scanning point of the magnetic detection unit and the thickness detection unit is as follows.
Setting the output standard of each scanning point as V when the magnetic detection unit does not detect the film to be detectedMThe output standard of each scanning point is V when the thickness detection unit does not detect the film to be detectedTThe control unit 4 controls the digital-to-analog converter to output a fixed voltage VMFor the magnetism detection unit, controlling the D/A converter to output a fixed voltage VTA thickness detection unit is provided, a magnetic detection unit and the thickness detection unit are started simultaneously, when the multifunctional sensor is not placed and used for detecting any film, a line of data is scanned and converted into a digital signal through a corresponding analog-to-digital converter, and a line of data of the magnetic detection unit is marked as VM1NAnd one line of data of the thickness detection unit is recorded as V11N。
The magnetic reference voltage correction module adopts a formula MRM1N＝MM+(MM-MM1N) (i.e., formula M)RMMN＝MM+(MM-MMMN) Taking M as 1Formula for time correspondence) to calculate the digital signal M corresponding to the corrected magnetic reference voltageRM1NThe thickness reference voltage correction module adopts a formula TRT1N＝TT+(TT-T11N) (i.e., formula T)RTMN＝TT+(TT-T1MN) The formula corresponding to the case where M is 1) is taken, the corrected thickness reference voltage T is calculatedRT1NDigital signal M corresponding to the corrected magnetic reference voltageRM1NAnd the corrected thickness reference voltage TRT1NIs stored in the storage unit.
In the subsequent detection process, the control unit 4 controls the digital-to-analog converter to output the magnetic reference voltage signal V corresponding to each magnetic detection point while the magnetic detection unit and the thickness detection unit sequentially output the data of each scanning pointRM1NTo the magnetic detection unit, the control unit 4 controls the digital-to-analog converter to output a thickness reference voltage signal V corresponding to each thickness detection pointRT1NIn the thickness detection unit, the outputs of all the magnetism detection units and the thickness detection unit are corrected.
The subsequent detection process and data processing process of the magnetic detection unit and the thickness detection unit are the same as those of embodiment 1, and are not described herein again.
From the above description, it can be seen that the above-described embodiments of the present application achieve the following technical effects:
1) the three detection units in the multifunctional sensor controlled by the control unit in the detection system can simultaneously detect three physical quantities of the film, the analog-to-digital conversion unit performs similar data processing on the three physical quantities, a data processing hardware device is simplified, and the detection system can generate images with the same resolution and different physical characteristics.
2) The detection method can detect three physical quantities of the film at the same time, and the analog-to-digital conversion unit performs similar data processing on the three physical quantities, so that a data processing hardware device is simplified, and the detection system can generate images with the same resolution and different physical characteristics.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (8)

1. A system for inspecting thin films, the system comprising:
the multifunctional sensor comprises three detection units, namely an optical detection unit, a magnetic detection unit and a thickness detection unit, wherein the three detection units are used for respectively carrying out optical detection, magnetic detection and thickness detection on each scanning point on a film to be detected;
the input end of the analog-to-digital conversion unit is electrically connected with the output end of the optical detection unit, the output end of the magnetic detection unit and the output end of the thickness detection unit, and the analog-to-digital conversion unit is used for converting the output signals of the three detection units into corresponding digital signals respectively; and
the control unit is electrically connected with the multifunctional sensor and the analog-to-digital conversion unit and is used for controlling the multifunctional sensor and the analog-to-digital conversion unit to work;
the detection system further comprises:
the input end of the correction unit is electrically connected with the output end of the analog-to-digital conversion unit, the control end of the correction unit is electrically connected with the control unit, and the correction unit is used for correcting the digital signal output by the analog-to-digital conversion unit;
the correction unit includes:
the correction coefficient acquisition module is electrically connected with the output end of the analog-to-digital conversion unit and is used for acquiring the correction coefficient of each detection unit corresponding to each scanning point; and
the calculation module is electrically connected with the correction coefficient acquisition module, corrects each digital signal output by the analog-to-digital conversion unit by adopting each correction coefficient, and the correction coefficients correspond to the digital signals output by the analog-to-digital conversion unit when the film to be detected is detected one by one;
the correction coefficient acquisition module includes:
an initial data obtaining module, configured to obtain initial data of each scanning point of each detection unit, where the initial data includes first initial data and second initial data, and the first initial data of the optical detection unit is optical first initial data L1MNThe second initial data of the optical detection unit is optical second initial data L2MNThe first initial data of the magnetic detection unit is magnetic first initial data M1MNThe second initial data of the magnetic detection unit is magnetic second initial data M2MNThe first initial data of the thickness detection unit is first initial thickness data T1MNThe second initial data of the thickness detection unit is second initial thickness data T2MNWherein M and N represent the row number and the column number of each scanning point respectively,
when the light source of the optical detection unit does not emit light, the digital signal corresponding to the optical detection data of each scanning point output by the analog-to-digital conversion unit is the optical first initial data L1MNWhen the light source emits light, after scanning the optical sample film at the focal point of the optical detection unit, the digital signal corresponding to the optical detection data of each scanning point output by the analog-to-digital conversion unit is the optical second initial data L2MNThe optical sample film is white paper without characters and images,
after the magnetic detection unit scans the magnetic sample film, the minimum digital signal corresponding to the magnetic detection data of each scanning point output by the analog-to-digital conversion unit is the magnetic first initial data M1MNAfter the magnetic detection unit scans the magnetic sample thin film, the maximum digital signal corresponding to the magnetic detection data of each scanning point output by the analog-to-digital conversion unit is the magnetic second initial data M2MNThe surface of the magnetic sample film is provided with a plurality of spaced rectangular magnetic strips，
When no film is placed on the multifunctional sensor, the digital signal corresponding to the thickness detection data output by the analog-to-digital conversion unit is the first initial thickness data T1MNAfter the thickness detection unit scans the thickness sample film, the digital signal output by the analog-to-digital conversion unit and corresponding to the thickness detection data of each scanning point is second initial data T of the thickness detection unit2MNThe thickness sample film is a film with uniform thickness; and
correction coefficient calculation module using formula K1MN= predetermined gray value/(L)2MN -L1MN) Calculating to obtain the optical correction coefficient K1MNBy the formula K2MN= predetermined gray value/(M)2MN -M1MN) Calculating to obtain the magnetic correction coefficient K2MNBy the formula K3MN= predetermined gray value/(T)2MN -T1MN) Calculating to obtain thickness correction coefficient K3MN;
The calculation module comprises:
optical computing module using formula (L)MN -L1MN)×K1MNFor the LMNPerforming a correction, wherein L isMNAfter the optical detection unit scans the film to be detected, the analog-to-digital conversion unit outputs digital signals corresponding to the optical detection data of each scanning point;
magnetic computing module, using formula (M)MN -M1MN)×K2MNFor the MMNPerforming a correction, wherein M isMNAfter the magnetic detection unit scans the film to be detected, the analog-to-digital conversion unit outputs digital signals corresponding to the magnetic detection data of each scanning point; and
thickness calculation module using formula (T)MN -T1MN)×K3MNOr (T)MN -T1MN)+TSFor the TMNPerforming a correction, wherein T isMNAfter the film to be detected is scanned by the thickness detection unit, the digital signal which is output by the analog-to-digital conversion unit and corresponds to the thickness detection data of each scanning pointNumber, said TSIs an offset gray value;
the detection system comprises:
and the storage unit is electrically connected with the correction unit and the control unit and is used for storing the correction coefficient and the initial data.
2. The detection system of claim 1, further comprising:
a digital-to-analog conversion unit electrically connected with the magnetic detection unit, the thickness detection unit, the storage unit and the control unit,
the digital-to-analog conversion unit is used for converting a digital signal corresponding to the corrected magnetic reference voltage into a voltage signal and inputting the voltage signal into the magnetic detection unit, and the digital-to-analog conversion unit is used for converting a digital signal corresponding to the corrected thickness reference voltage into a voltage signal and inputting the voltage signal into the thickness detection unit, wherein the corrected magnetic reference voltage is used for correcting a signal output when the magnetic detection unit detects the signal, and the corrected thickness reference voltage is used for correcting a signal output when the thickness detection unit detects the signal.
3. The detection system according to claim 2, wherein the correction unit further comprises:
a magnetic reference voltage correction module adopting formula MRMMN=MM+（MM-MMMN) Calculating the digital signal M corresponding to the corrected magnetic reference voltageRMMNWherein, the MMIs a magnetic reference voltage VMCorresponding digital signal, said MMMNA magnetic detection voltage V of each scanning point when no film is placedMMNA corresponding digital signal;
thickness reference voltage correction module using formula TRTMN=TT+（TT-T1MN) Calculating the corrected thickness reference voltage TRTMNWherein, the T isTFor thickness referencePressure VTCorresponding digital signal, said T1MNIs thickness first initial data, which is thickness detection voltage V of each scanning point when the multifunctional sensor is not placed with any film1MNA corresponding digital signal.
4. A method of inspecting a thin film, the method comprising:
step S1, using three detection units of the multifunctional sensor to respectively perform optical detection, magnetic detection and thickness detection on each scanning point on the film to be detected, wherein the three detection units are respectively an optical detection unit, a magnetic detection unit and a thickness detection unit; and
step S2, converting the output signals of the three detection units into corresponding digital signals respectively;
the detection method further comprises the following steps:
a step S3 of correcting the digital signal obtained in the step S2;
before the step S1, the detection method further includes:
correcting a magnetic reference voltage and inputting the magnetic reference voltage into the magnetic detection unit, wherein the corrected magnetic reference voltage corrects a signal output when the magnetic detection unit detects the magnetic reference voltage; and
correcting a thickness reference voltage and inputting the thickness reference voltage into the thickness detection unit, wherein the corrected thickness reference voltage corrects a signal output when the thickness detection unit detects the thickness;
the process of correcting the magnetic reference voltage includes:
inputting the magnetic reference voltage V to the magnetic detection unitM；
When the multifunctional sensor is not provided with any film, the magnetic detection unit is started and outputs a plurality of magnetic detection voltages VMMN；
The V is put intoMAnd said VMMNRespectively converted into digital signals MMAnd MMMNBy the formulaMRMMN=MM+（MM-MMMN) Calculating the digital signal M corresponding to the corrected magnetic reference voltageRMMN；
The M is addedRMMNConverted into a voltage signal VRMMN，
The process of correcting the thickness reference voltage includes:
inputting the thickness reference voltage V to the thickness detecting unitT；
When the multifunctional sensor is not provided with any film, the thickness detection unit is started and outputs a plurality of thickness detection voltages V1MN；
The V is put intoTAnd said V1MNRespectively converted into digital signals TTAnd T1MNBy the formula TRTMN=TT+（TT-T1MN) Calculating a digital signal T corresponding to the corrected thickness reference voltageRTMN；
Will be the TRTMNConverted into a voltage signal VRTMN。
5. The detection method according to claim 4, wherein before the step S3, the detection method further comprises:
step a, acquiring a correction coefficient of each detection unit corresponding to each scanning point, where the correction coefficient is used to correct the digital signal acquired in step S2.
6. The detection method according to claim 5, wherein the step A comprises:
step A1, obtaining initial data of each detection unit, wherein the initial data comprises optical first initial data L1MNOptical second initial data L2MNMagnetic first initial data M1MNMagnetic second initial data M2MNFirst initial data T of thickness1MNSecond initial data T of thickness2MNWherein M and N represent the row number and the column number of the scanning point respectively,
when the light source of the optical detection unit does not emit light, a digital signal obtained by performing analog-to-digital conversion on optical detection data output by the optical detection unit is the optical first initial data L1MNWhen the light source emits light, after scanning the optical sample film at the focal point of the optical detection unit, the digital signal obtained by performing analog-to-digital conversion on the optical detection data at each scanning point is the optical second initial data L2MN，
After the magnetic detection unit scans the magnetic sample film, the minimum digital signal of the magnetic detection data of each scanning point after analog-to-digital conversion is the magnetic first initial data M1MNAfter the magnetic detection unit scans the magnetic sample film, the maximum digital signal of the magnetic detection data of each scanning point after analog-to-digital conversion is the magnetic second initial data M2MN，
When no film is placed on the multifunctional sensor, the digital signal of the thickness detection data output by the thickness detection unit after the analog-to-digital conversion is the first initial thickness data T1MNWhen the thickness detection unit scans the thickness sample film, the digital signal of the thickness detection data of each scanning point after analog-to-digital conversion is the second initial data T of the thickness detection unit2MN(ii) a And
step A2, calculating the correction coefficient by using the initial data, and adopting formula K1MN= predetermined gradation value/(L)2MN -L1MN) Calculating to obtain the optical correction coefficient K1MNBy the formula K2MN= predetermined gray value/(M)2MN -M1MN) Calculating to obtain the magnetic correction coefficient K2MN，Using the formula KMN= predetermined gray value/(T)2MN-T1MN) Calculating to obtain thickness correction coefficient KMN。
7. The detection method according to claim 6, wherein the step S3 includes:
using the formula (L)MN -L1MN)×K1MNFor the LMNMake correctionsWherein, said LMNAfter the optical detection unit scans the film to be detected, digital signals corresponding to optical detection data of each scanning point are output after analog-to-digital conversion;
using the formula (M)MN -M1MN)×K2MNFor the MMNPerforming a correction, wherein M isMNAfter the magnetic detection unit scans the film to be detected, digital signals corresponding to the magnetic detection data of each scanning point are output after analog-to-digital conversion; and
using the formula (T)MN -T1MN)×K3MNOr (T)MN -T1MN)+TSFor the TMNPerforming a correction, wherein T isMNAfter the film to be detected is scanned by the thickness detection unit, the digital signal corresponding to the thickness detection data of each scanning point is output after analog-to-digital conversion, and T isSAre offset gray scale values.
8. The detection method according to claim 6, further comprising:
and storing the correction coefficient and the initial data.
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