Reflection-type linear scanning hyperspectral on-line measurement system and method based on scintillation light source

Abstract

The invention belongs to the related technical field of thin film optical online measurement, and discloses a reflective linear scanning hyperspectral online measurement system and method based on a flickering light source, the measurement system comprises a linear scanning adaptive control module, the linear scanning adaptive control module is used for carrying out linear scanning adaptive control on a to-be-measured sample, and the linear scanning adaptive control module is used for carrying out linear scanning adaptive control on the to-be-measured sample; the three-dimensional hyperspectral data of the whole breadth is obtained; the line scanning self-adaptive module comprises a line scanning sample speed detection unit and a line scanning control unit, and the line scanning sample speed detection unit is used for detecting the conveying speed of a to-be-detected sample in real time and sending the conveying speed information of the sample to the line scanning control unit; the line scanning control unit is used for receiving the transmission speed information of the sample to be detected in real time, and adaptively calculating the light source flicker period, the single flicker duration and the camera exposure time. The single measurement time of the measurement system is in a microsecond level, and accurate online detection and process control feedback of the thickness of a full-width film in roll-to-roll and sheet-to-sheet processes are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field related to on-line measurement of thin film optics, and more specifically, relates to a reflection type line-scanning hyperspectral on-line measurement system and method based on a scintillating light source. Background Art

[0002] Roll-to-Roll production technology is an efficient, low-cost and scalable manufacturing technology, which is widely used in flexible OLED display panels, flexible solar panels, flexible electronic circuit boards, etc. This technology unwinds the thin film material from one reel and processes it through continuous process steps, and finally winds it onto another reel again, with the advantages of high efficiency, low cost and high scalability. It allows for large-scale production. Since the entire thin film production process can be automated and a large number of thin film products can be continuously produced, the Roll-to-Roll production technology is suitable for the rapid large-scale production of thin films.

[0003] During the Roll-to-Roll thin film manufacturing process, the thin film material is first unwound from one reel and then processed through a series of process steps. These process steps include coating, printing, evaporation, deposition, lithography, stripping, cleaning, etc. Each process step can be carried out on a continuous substrate, enabling the entire manufacturing process to be carried out efficiently. Among all the performance indicators of the Roll-to-Roll thin film production process, the thickness of the thin film is the most important indicator to measure its quality. Controlling the thin film thickness uniformity within the production requirement range is an important prerequisite for ensuring other properties of the Roll-to-Roll thin film.

[0004] The existing on-line monitoring methods for thin film thickness are mainly optical measurement methods, including spectroscopic ellipsometer, spectroscopic reflectometer, color confocal technology, etc.; among them, according to the type of light spot, it is divided into single-point and imaging measurement.

[0005] The single-point spectroscopic reflectometer has the characteristics of fast and accurate measurement; the single-point spectroscopic ellipsometer has the characteristics of accurate measurement results and containing more thin film information other than the film thickness; the color confocal technology can realize the measurement of the thin film thickness and profile; the single-point optical measurement methods cannot meet the requirements of fast and full-width measurement during the Roll-to-Roll production process. The imaging ellipsometer can accurately measure the film thickness of the Roll-to-Roll thin film, but due to reasons such as the modulation of the beam polarization state and large-angle oblique incidence, there are disadvantages such as inconsistent light spot focusing, complex optical path, and large amount of data calculation.

[0006] In all of the above methods, since the measurement beam is continuously irradiated in the time dimension, the conveying speed of the roll-to-roll film production line is fast, and the measurement system takes a relatively long time, generally in the millisecond level, to receive the beam carrying the sample information. This will result in a relatively low spatial resolution in the sample conveying direction during roll-to-roll production, causing a film thickness aliasing effect and inaccurate measurement results of the film thickness information. Therefore, it is necessary to propose a full-width film online measurement system that uses a single measurement in an extremely short time to meet the technical requirements of rapid and large-width production of films during the roll-to-roll production process and achieve accurate online measurement of the film thickness during film production. Summary of the Invention

[0007] In view of the above defects or improvement requirements of the prior art, the present invention provides a reflection-type line-scanning hyperspectral online measurement system and method based on a flashing light source. The single measurement time of the system is in the microsecond level, realizing precise online detection and process control feedback of the full-width film thickness in roll-to-roll and sheet-to-sheet processes.

[0008] To achieve the above object, according to one aspect of the present invention, there is provided a reflection-type line-scanning hyperspectral online measurement system based on a flashing light source. The measurement system is for online film thickness detection in roll-to-roll and sheet-to-sheet processes, and includes a line-scanning adaptive control module. The line-scanning adaptive control module is used to perform line-scanning adaptive control on a sample to be measured to obtain full-width three-dimensional hyperspectral data;

[0009] The line-scanning adaptive module includes a line-scanning sample speed detection unit and a line-scanning control unit. The line-scanning sample speed detection unit is used to detect the conveying speed of the sample to be measured in real time and send the conveying speed information of the sample to the line-scanning control unit; the line-scanning control unit is used to receive the conveying speed information of the sample to be measured in real time, adaptively calculate the light source flashing period, the single flashing duration, and the camera exposure time that match the set line-scanning spatial frequency, and send a trigger signal to the flashing broadband light source and the high-resolution hyperspectral imaging camera.

[0010] Further, the trigger signal is used to control the pulse time window of the flashing power supply within the full-frame exposure time window of the high-resolution imaging camera, and is applicable to both global shutter and rolling shutter.

[0011] Further, the flashing broadband light source receives the trigger signal in real time and controls the light source flashing period and the single flashing duration; the high-resolution hyperspectral imaging camera synchronously receives the trigger signal and controls the camera exposure time window; the flashing broadband light source and the high-resolution hyperspectral imaging camera achieve synchronization of the flashing period and the exposure period.

[0012] Further, the measurement system further includes a high-speed flashing line illumination light source module, a high-resolution hyperspectral spectroscopic imaging module, and an on-line thin film data monitoring module; the high-speed flashing line illumination module includes linearly densely arranged optical fibers, which are used to generate a flashing linear light beam to irradiate the sample to be measured at a certain angle; the high-resolution hyperspectral spectroscopic imaging module is used to collect the linear interference light beam generated after the linear light beam irradiates the sample to be measured, and generate a high-resolution two-dimensional hyperspectral image with position dimension and spectral dimension; the on-line thin film data monitoring module is used to perform spectral frequency analysis or modeling curve fitting on the obtained three-dimensional hyperspectral data in real time, so as to obtain and display in real time the real-time on-line detection results of the full-frame mask thickness and film thickness non-uniformity at a set spatial resolution.

[0013] Further, the high-speed flashing line illumination light source module includes a high-speed flashing light source lamp box and a linear optical fiber light guide; the high-speed flashing lamp box is used to provide high-intensity spatial light with a specific band spectrum at the light outlet, and its flashing period and single flashing duration can both be set, and the single flashing duration is in the microsecond level; the linear optical fiber light guide realizes linear illumination through the dense arrangement of the optical fiber bundle and the focusing of the cylindrical lens.

[0014] Further, the high-speed flashing light source lamp box is internally provided with a flashing broadband light source and a filter; the flashing broadband light source is used to provide a high-intensity pulsed light source with continuous and stable spectrum; the filter is used to screen the spectrum of a predetermined band and provide high-intensity spatial light of the spectrum of the predetermined band at the light outlet of the high-speed flashing light source lamp box.

[0015] Further, the high-resolution hyperspectral spectroscopic imaging module includes an imaging objective lens, a hyperspectral spectroscopic module, and a high-resolution imaging camera; the hyperspectral spectroscopic module includes a slit, a converging lens, and a grating, which are used to spectroscopically split the line spot spectrum at the slit to form a two-dimensional hyperspectral light beam; the imaging objective lens is used to receive the linear interference light beam, modulate the linear interference light beam into a parallel light beam and project it onto the slit; the high-resolution imaging camera is used to image the two-dimensional hyperspectral light beam and output a two-dimensional hyperspectral image.

[0016] Further, the single acquisition time window of the high-resolution hyperspectral spectroscopic imaging module includes the single pulse time window of the high-speed flashing line illumination light source; the continuous acquisition period of the high-resolution hyperspectral spectroscopic imaging module is consistent with the flashing period of the high-speed flashing line illumination light source, and is used to continuously collect the interference light beam after irradiating the sample to be measured at each flashing moment.

[0017] Further, the online film thickness data monitoring module includes a line-scan spectral data processing unit and a thin film detection online interaction unit; the line-scan spectral data processing unit is used to perform spectral frequency analysis or modeling curve fitting on the full-frame three-dimensional hyperspectral data obtained by the measurement system in real time, so as to calculate and obtain the online detection results of the full-frame film thickness and film thickness non-uniformity at a set spatial resolution; the thin film detection online interaction unit is used to display in real time the online detection results of the full-frame film thickness and film thickness non-uniformity at a set spatial resolution calculated by the line-scan spectral data processing unit.

[0018] The present invention also provides a reflection type line-scan hyperspectral online measurement method based on a flashing light source. The measurement method measures the film thickness by using the reflection type line-scan hyperspectral online measurement system as described above.

[0019] Generally speaking, compared with the prior art through the above technical solutions conceived by the present invention, the reflection type line-scan hyperspectral online measurement system and method provided by the present invention mainly have the following beneficial effects:

[0020] 1. Aiming at the characteristics of fast film transfer speed in the roll-to-roll process, the line-scan adaptive control module of the present invention detects the film transfer speed in real time, and adaptively sets the flashing period and single-flash duration of the high-speed flashing line illumination light source in real time according to the film line-scan spatial resolution set by the online film data monitoring module, so as to enable the high-resolution hyperspectral spectroscopic imaging module to complete the single acquisition of the line beam within the time of microseconds, thereby improving the film spatial resolution in the line-scan direction, and at the same time improving the signal-to-noise ratio of the reflected spectral signal and enhancing the accuracy of the film thickness information.

[0021] 2. Aiming at the characteristics of real-time online production in the film roll-to-roll process, the online scan adaptive control module of the present invention detects the conveying speed of the line-scan sample in real time through the line-scan sample speed monitoring unit, and feeds back the conveying speed information to the line-scan control unit. The line-scan control unit receives the conveying speed information in real time and calculates, and adaptively feedback-controls the flashing period and single-flash duration of the flashing wide-spectrum light source, so as to realize the online measurement with line-scan speed adaptability, and feed back the process production line of the film process in real time to adjust the film process online, ensuring the continuity of the film roll-to-roll production and the practicality of the operation.

[0022] 3. For the characteristic of large film width in the film roll-to-roll manufacturing process, the high-speed flashing line illumination light source module of the present invention is composed of a high-speed flashing light source lamp box and a linear optical fiber light guide. The linear optical fiber light guide realizes high-intensity and spatially continuous and uniform linear illumination through the linear dense arrangement of optical fiber bundles and the focusing of a cylindrical lens, which can better cover the full width of the roll-to-roll film to be measured, thereby increasing the amount of film thickness data in the full width in the transverse direction and improving the scientific nature of the on-line monitoring of roll-to-roll films.

[0023] 4. For the characteristics of continuous and large-scale production in the film roll-to-roll manufacturing process, the flashing wide-spectrum light source of the present invention can provide a high-intensity flashing light source with continuous and stable spectrum, including but not limited to a flashing xenon lamp. Its lifespan is determined by the number of flashes, rather than the continuous lighting time as in the case of traditional continuous illumination light sources. Therefore, the system of the present invention can adjust the flashing frequency of the flashing wide-spectrum light source by setting the on-line film line scan spatial resolution, under the condition of meeting the production requirements of the actual film roll-to-roll process, thereby increasing the service life of the light source and further reducing the usage cost of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of a reflection type line scan hyperspectral on-line measurement system based on a flashing light source provided by the present invention;

[0025] Figure 2 is Figure 1 a schematic diagram of the measurement system in

[0026] Figure 3 is Figure 1 a diagram of adjustable parameters of the flashing wide-spectrum light source of the measurement system in

[0027] Figure 4 is Figure 1 a synchronous timing diagram of the measurement system in

[0028] Figure 5 is Figure 1 a synchronous timing diagram of the measurement system in

[0029] Figure 6 is Figure 1 a flowchart of line scan adaptive synchronous control of the measurement system in

[0030] Figure 7 In Figure 1 schematic diagrams of measurement spots of the measurement system in

[0031] Figure 8 InFigure 1 Schematic diagram of the continuous light source large spot film thickness aliasing film involved in the measurement system in

[0032] Figure 9 is Figure 1 Schematic diagram of the reflectivity of the continuous light source large spot film thickness aliasing film involved in the measurement system in

[0033] Figure 10 In (a) and (b) are respectively the comparison schematic diagrams of the pulsed light source small spot and the continuous light source large spot films;

[0034] Figure 11 is the comparison schematic diagram of the reflectivities of the pulsed light source small spot and the continuous light source large spot films;

[0035] Figure 12 is the module schematic diagram of the reflection type line scan hyperspectral online measurement system based on the scintillating light source provided by the present invention.

[0036] In all the drawings, the same reference numerals are used to represent the same elements or structures, where: 1 - high-speed scintillating line illumination light source module, 2 - high-resolution hyperspectral spectroscopic imaging module, 3 - line scan adaptive control module, 4 - online film data monitoring module. Detailed implementation manners

[0037] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various implementation manners of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] The present invention provides a reflection type line scan hyperspectral online measurement system based on a scintillating light source. The measurement system is for online film thickness detection in roll-to-roll and sheet-to-sheet processes. The single measurement time reaches the microsecond level, realizing accurate online detection of the film thickness of the entire width film in roll-to-roll and sheet-to-sheet processes and process control feedback.

[0039] The measurement system includes a high-speed scintillating line illumination light source module, a high-resolution hyperspectral spectroscopic imaging module, a line scan adaptive control module, and an online film data monitoring module. Among them, the high-speed scintillating line illumination module includes linearly closely arranged optical fibers, which are used to generate a high-speed scintillating linear light beam and irradiate the sample to be measured at a certain angle.

[0040] The high-resolution hyperspectral spectroscopic imaging module is used to collect the linear interference light beam generated after the linear light beam irradiates the sample to be measured, and generate a high-resolution two-dimensional hyperspectral image with position dimension and spectral dimension.

[0041] The line-scanning adaptive control module is used to perform line-scanning adaptive control on the sample to be measured, so as to obtain full-frame three-dimensional hyperspectral data. The on-line thin-film data monitoring module is used to perform spectral frequency analysis or modeling curve fitting on the obtained three-dimensional hyperspectral data in real time, so as to obtain and display in real time the on-line detection results of the full-frame film thickness and film thickness non-uniformity at the set spatial resolution.

[0042] The measurement system is for on-line thin-film thickness detection in roll-to-roll and sheet-to-sheet processes. The single measurement time reaches the microsecond level, realizing accurate on-line monitoring of the full-frame film thickness and process control feedback in roll-to-roll and sheet-to-sheet processes.

[0043] The high-speed flashing line illumination light source module includes a high-speed flashing light source lamp box and a linear optical fiber light guide. The high-speed flashing lamp box is used to provide high-intensity spatial light with a specific band spectrum at the light output port, and its flashing period and single-flash duration can be set, and the single-flash duration is at the microsecond level. The linear optical fiber light guide realizes high-intensity and spatially continuous and uniform linear illumination through the dense arrangement of the optical fiber bundles and the focusing of the cylindrical lens.

[0044] The high-speed flashing light source lamp box is internally provided with a flashing broadband light source and a filter. The flashing broadband light source is used to provide a high-intensity pulsed light source with a continuous and stable spectrum, including but not limited to a flashing xenon lamp; the pulse period and pulse width of the flashing broadband light source are adjustable. The filter is used to screen a specific band spectrum and provide high-intensity spatial light with a specific band spectrum at the light output port of the high-speed flashing light source lamp box.

[0045] The high-resolution hyperspectral spectroscopic imaging module includes an imaging objective lens, a hyperspectral spectroscopic module and a high-resolution imaging camera. The hyperspectral spectroscopic module includes a slit, a converging lens and a grating, which is used to spectroscopically analyze the line spot spectrum at the slit to form a two-dimensional hyperspectral light beam. The imaging objective lens is used to receive the linear interference light beam, modulate the linear interference light beam into a parallel light beam and project it onto the slit. The high-resolution imaging camera is used to image the two-dimensional hyperspectral light beam and output a two-dimensional hyperspectral image. The imaging sensor of the high-resolution imaging camera includes but is not limited to a charge-coupled device (CCD) and a complementary metal-oxide-semiconductor (CMOS), etc., and its shutter modes include global shutter and rolling shutter, etc.

[0046] The single acquisition time window of the high-resolution hyperspectral spectroscopic imaging module includes the single pulse time window of the high-speed flashing line illumination light source. The continuous acquisition period of the high-resolution hyperspectral spectroscopic imaging module is consistent with the flashing period of the high-speed flashing line illumination light source, and is used to continuously acquire the interference light beams after irradiating the sample to be measured at each flashing moment.

[0047] The line scan adaptive module includes a line scan sample speed detection unit and a line scan control unit. The line scan sample speed detection unit is used to detect the transmission speed of the line scan sample in real time and send the transmission speed information of the sample to the line scan control unit. The line scan control unit is used to receive the transmission speed information of the line scan sample in real time, adaptively calculate the light source flashing period, the single flashing duration, and the camera exposure time that match the set line scan spatial frequency, and send a trigger signal to the flashing broadband light source and the high-resolution hyperspectral imaging camera.

[0048] The trigger signal is used to control the pulse time window of the flashing power supply within the full-frame exposure time window of the high-resolution imaging camera, and is applicable to both global shutter and rolling shutter.

[0049] The flashing broadband light source receives the trigger signal in real time and controls the light source flashing period and the single flashing duration. The high-resolution hyperspectral imaging camera synchronously receives the trigger signal and controls the camera exposure time window. The flashing broadband light source and the high-resolution hyperspectral imaging camera achieve synchronization of the flashing period and the exposure period, the flashing pulse is included in the full-frame exposure time window, and the measurement system realizes synchronous acquisition of the linear interference light beam.

[0050] For the synchronous acquisition of the measurement system, the online film thickness detection using a pulsed light source has a higher spatial resolution in the line scan direction compared to the online film thickness detection using a continuous light source. The spot in the line scan direction for a single measurement is extremely small, greatly reducing the effect of poor signal-to-noise ratio of reflectivity caused by the film thickness aliasing effect of the continuous light source.

[0051] The information acquired by the measurement system in a single acquisition is the film thickness information in the length direction of the linear interference light beam, and the spot in the line scan direction is regarded as a single point. For the online detection using a continuous light source, the spot acquired by the measurement system in a single acquisition is larger in the line scan direction, and there is a high possibility that the film thickness is uneven in the spot area in the line scan direction, resulting in the film thickness aliasing effect. The film thickness aliasing effect will superimpose the reflectivity signals caused by different film thicknesses at multiple positions, reducing the signal intensity of the reflectivity and affecting the signal-to-noise ratio of the measurement system.

[0052] The line-scanning sample speed detection unit is used to detect the transmission speed of the sample, including but not limited to the linear transmission speed of the sample, the rotational transmission speed of the sample, etc. The on-line film thickness data monitoring module includes a line-scanning spectral data processing unit and a thin film detection on-line interaction unit. The line-scanning spectral data processing unit is used to perform spectral frequency analysis or modeling curve fitting on the full-frame three-dimensional hyperspectral data obtained by the measurement system in real time, so as to calculate and obtain the on-line detection results of the full-frame film thickness and film thickness non-uniformity at a set spatial resolution. The thin film detection on-line interaction unit is used to display in real time the on-line detection results of the full-frame film thickness and film thickness non-uniformity at the set spatial resolution calculated by the line-scanning spectral data processing unit.

[0053] The thin film detection on-line interaction unit is used to receive parameters such as the type of thin film and the spatial resolution for on-line thin film detection set by the user, and transmit the user-set parameters to the line-scanning spectral data processing unit. The line-scanning spectral data processing unit is used to transmit the detection results of the full-frame film thickness and film thickness non-uniformity at the set spatial resolution calculated in real time to the thin film detection on-line interaction unit, and feedback to the thin film manufacturing process production line in real time to adjust the thin film manufacturing process on-line.

[0054] The present invention will be further described in detail below in conjunction with embodiments and the accompanying drawings.

[0055] As Figure 1 shown, a reflection-type line-scanning hyperspectral on-line measurement system based on a flashing light source includes a high-speed flashing line illumination light source module 1, a high-resolution hyperspectral spectroscopic imaging module 2, a line-scanning adaptive control module 3, and an on-line thin film data monitoring module 4.

[0056] As Figure 2 shown, the on-line measurement system of the present invention is applicable to on-line detection of large-width roll-to-roll production films; the high-speed flashing line illumination light source module uses linearly densely arranged optical fibers to generate a high-speed flashing linear light beam, which irradiates the sample to be measured at a certain angle; the high-resolution hyperspectral spectroscopic imaging module is used to collect the linear interference light beam after the linear light beam generated by the flashing line illumination light source module irradiates the sample to be measured, and generate a high-resolution two-dimensional hyperspectral image with position dimension and spectral dimension.

[0057] The line-scanning adaptive control module is used to perform line-scanning adaptive control on the sample to be measured to obtain full-frame three-dimensional hyperspectral data; the on-line thin film data monitoring module is used to perform spectral frequency analysis or modeling curve fitting on the full-frame three-dimensional hyperspectral data obtained by the measurement system in real time, and obtain and display in real time the real-time on-line detection results of the full-frame film thickness and film thickness non-uniformity at a set spatial resolution.

[0058] The measurement system is for on-line thin film thickness detection in roll-to-roll and sheet-to-sheet processes. The single measurement time reaches the microsecond level, realizing accurate on-line monitoring of the full-width film thickness and process control feedback in roll-to-roll and sheet-to-sheet processes.

[0059] The high-speed flashing line illumination light source module is composed of a high-speed flashing light source lamp box and a linear optical fiber light guide. The high-speed flashing light source lamp box is used to provide high-intensity spatial light with a specific band spectrum at the light output port, and its flashing period and single flashing duration can be set. The single flashing duration is at the microsecond level. The linear optical fiber light guide realizes high-intensity and spatially continuous and uniform linear illumination through the linear dense arrangement of optical fiber bundles and the focusing of a cylindrical lens.

[0060] The lamp box is internally provided with a flashing wide-spectrum light source and a filter. The flashing wide-spectrum light source is used to provide a high-intensity pulsed light source with a continuous and stable spectrum, including but not limited to a flashing xenon lamp.

[0061] As Figure 3 shown, the pulse period and pulse width of the flashing wide-spectrum light source are adjustable. The filter is used to screen a specific band spectrum and provide high-intensity spatial light with a specific band spectrum at the light output port of the lamp box.

[0062] The high-resolution hyperspectral spectroscopic imaging module is composed of an imaging objective lens, a hyperspectral spectroscopic module, and a high-resolution imaging camera. The hyperspectral spectroscopic module is composed of a slit, a converging lens, a grating, etc., and is used to spectroscopically analyze the line spot spectrum at the slit to form a two-dimensional hyperspectral light beam.

[0063] The imaging objective lens is used to receive the linear interference light beam and modulate the linear interference light beam into a parallel light beam and project it onto the slit. The high-resolution imaging camera is used for imaging the two-dimensional hyperspectral light beam and outputting a two-dimensional hyperspectral image. Its imaging sensor includes but not limited to a charge-coupled device (CCD) and a complementary metal-oxide-semiconductor (CMOS), etc. Its shutter modes include a global shutter and a rolling shutter, etc.

[0064] The single acquisition time window of the high-resolution hyperspectral spectroscopic imaging module includes the single pulse time window of the high-speed flashing line illumination light source. The continuous acquisition period of the high-resolution hyperspectral spectroscopic imaging module is consistent with the flashing period of the high-speed flashing line illumination light source, and is used to continuously acquire the interference light beam after irradiating the sample to be measured at each flashing moment.

[0065] The line scan adaptive control module consists of a line scan sample speed detection unit and a line scan control unit; the line scan sample speed detection unit is used to detect the transmission speed of the line scan sample in real time and send the sample transmission speed information to the line scan control unit; the line scan control unit is used to receive the line scan sample transmission speed information in real time, adaptively calculate the light source flashing period, the single flash duration, and the camera exposure time that match the set line scan spatial resolution, and send a trigger signal to the flashing broadband light source and the high-resolution hyperspectral imaging camera.

[0066] As Figure 4 and Figure 5 shown, the trigger signal is used to control the pulse time window of the flashing light source within the full-frame exposure time window of the high-resolution imaging camera, and is applicable to both global shutter and rolling shutter.

[0067] As Figure 6 shown, the flashing broadband light source receives the trigger signal in real time and controls the light source flashing period and the single flash duration; the high-resolution hyperspectral imaging camera synchronously receives the trigger signal and controls the exposure time window of the camera; the flashing broadband light source and the high-resolution hyperspectral imaging camera achieve synchronization of the flashing period and the exposure period, the flashing pulse is included in the full-frame exposure time window, and the measurement system realizes synchronous acquisition of the linear interference light beam.

[0068] Please refer to Figure 7 , for the synchronous acquisition of the measurement system, the online film thickness detection using a pulsed light source has a higher spatial resolution in the line scan direction compared to the online film thickness detection using a continuous light source. The spot in the line scan direction for a single measurement is extremely small, greatly reducing the effect of poor signal-to-noise ratio of reflectivity caused by the film thickness aliasing effect of the continuous light source.

[0069] The information collected by the measurement system for a single time is the film thickness information in the length direction of the linear interference light beam, and the spot in the line scan direction is regarded as a single point. As Figure 8 shown, for the online detection using a continuous light source, the spot collected by the measurement system for a single time is relatively large in the line scan direction, and there is a high possibility that the film thickness in the spot area in the line scan direction is uneven, resulting in the film thickness aliasing effect.

[0070] As Figure 9 shown, the film thickness aliasing effect will superimpose the reflectivity signals caused by different film thicknesses at multiple positions, reducing the intensity of the reflectivity signal and affecting the signal-to-noise ratio of the measurement system.

[0071] As Figure 10 shown, for the online detection using a pulsed light source, the spot collected by the measurement system for a single time is extremely small in the line scan direction, and the film thickness difference in the spot area in the line scan direction is not large, making it not easy to cause the film thickness aliasing effect.

[0072] As Figure 11 shown, for the extremely small spot collected in a single acquisition of the on-line detection of the pulsed light source, compared with the large spot collected in a single acquisition of the on-line detection of the continuous light source, the reflectivity signal of the measurement system is stronger and the signal-to-noise ratio of the system is larger.

[0073] The line-scanning sample speed detection unit is used to detect the transmission speed of the sample, including but not limited to the linear transmission speed of the sample and the rotational transmission speed of the sample, etc. The on-line thin film data monitoring module is composed of a line-scanning spectral data processing unit and an on-line interaction unit for thin film detection.

[0074] The line-scanning spectral data processing unit is used to perform spectral frequency analysis or modeling curve fitting on the full-frame three-dimensional hyperspectral data obtained by the measurement system in real time, so as to calculate and obtain the on-line detection results of the full-frame film thickness and film thickness non-uniformity at a set spatial resolution.

[0075] The on-line interaction unit for thin film detection is used to display in real time the on-line detection results of the full-frame film thickness and film thickness non-uniformity at a set spatial resolution calculated by the line-scanning spectral data processing unit. As Figure 12 shown, the on-line interaction unit for thin film detection is used to receive parameters such as the type of thin film and spatial resolution of the on-line thin film detection set by the user, and transmit the user-set parameters to the line-scanning spectral data processing unit.

[0076] The line-scanning spectral data processing unit transmits the detection results of the full-frame film thickness and film thickness non-uniformity at a set spatial resolution calculated in real time to the on-line interaction unit for thin film detection, and feeds back to the thin film manufacturing process production line in real time to adjust the thin film manufacturing process on-line.

[0077] The present invention also provides a reflection type line-scanning hyperspectral on-line measurement method based on a scintillation light source. The measurement method measures the film thickness by using the reflection type line-scanning hyperspectral on-line measurement system as described above.

[0078] It is easy for those skilled in the art to understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A reflection type line-scanning hyperspectral on-line measurement system based on a flashing light source, characterized in that: The measurement system is for on-line film thickness detection in roll-to-roll and sheet-to-sheet processes, and includes a line-scanning adaptive control module, which is used for performing line-scanning adaptive control on a sample to be measured to obtain full-frame three-dimensional hyperspectral data; The line-scanning adaptive module includes a line-scanning sample speed detection unit and a line-scanning control unit. The line-scanning sample speed detection unit is used for detecting the conveying speed of the sample to be measured in real time and sending the conveying speed information of the sample to the line-scanning control unit; the line-scanning control unit is used for receiving the conveying speed information of the sample to be measured in real time, adaptively calculating the light source flashing period, the single-flash duration and the camera exposure time that match the set line-scanning spatial frequency, and sending a trigger signal to the flashing broadband light source and the high-resolution hyperspectral imaging camera.

2. The reflective line-scanning hyperspectral online measurement system based on a flashing light source according to claim 1, wherein: The trigger signal is used for controlling the pulse time window of the flashing power supply within the full-frame exposure time window of the high-resolution imaging camera, and is applicable to both global shutter and rolling shutter.

3. The reflection type line-scanning hyperspectral on-line measurement system based on a flashing light source according to claim 2, characterized in that: The flashing broadband light source receives the trigger signal in real time and controls the light source flashing period and the single-flash duration; The high-resolution hyperspectral imaging camera synchronously receives the trigger signal and controls the camera exposure time window; the flashing broadband light source and the high-resolution hyperspectral imaging camera achieve synchronization of the flashing period and the exposure period.

4. The reflection-type line-scanning hyperspectral online measurement system based on a flashing light source according to claim 1, wherein: The measurement system further includes a high-speed flashing line illumination light source module, a high-resolution hyperspectral spectroscopy imaging module and an on-line film data monitoring module; the high-speed flashing line illumination module includes linearly densely arranged optical fibers, which are used for generating a flashing linear light beam to irradiate the sample to be measured at a certain angle; the high-resolution hyperspectral spectroscopy imaging module is used for collecting the linear interference light beam generated after the linear light beam irradiates the sample to be measured and generating a high-resolution two-dimensional hyperspectral image with position dimension and spectral dimension; The on-line film data monitoring module is used for performing spectral frequency analysis or modeling curve fitting on the obtained three-dimensional hyperspectral data in real time to obtain and display in real time the on-line detection results of the full-frame film thickness and film thickness non-uniformity at a set spatial resolution.

5. The reflective line-scanning hyperspectral online measurement system based on a flashing light source according to claim 4, wherein: The high-speed flashing line illumination light source module includes a high-speed flashing light source lamp box and a linear optical fiber light guide; the high-speed flashing lamp box is used for providing high-intensity spatial light with a specific band spectrum at the light outlet, and both its flashing period and single-flash duration can be set, and the single-flash duration is at the microsecond level; the linear optical fiber light guide realizes linear illumination through densely arranged optical fiber bundles and condensing by a cylindrical lens.

6. The reflective line-scanning hyperspectral on-line measurement system based on a flashing light source according to claim 5, wherein: The high-speed flashing light source lamp box is internally provided with a flashing broadband light source and a filter. The flashing broadband light source is used for providing a high-intensity pulsed light source with continuous and stable spectrum; the filter is used for screening the spectrum of a predetermined band and providing high-intensity spatial light of the spectrum of the predetermined band at the light outlet of the high-speed flashing light source lamp box.

7. The reflection type line-scanning hyperspectral online measurement system based on a flashing light source according to claim 5, characterized in that: The high-resolution hyperspectral spectroscopic imaging module includes an imaging objective lens, a hyperspectral spectroscopic module, and a high-resolution imaging camera; the hyperspectral spectroscopic module includes a slit, a converging lens, and a grating, which are used to spectroscopically analyze the spectral line spot at the slit to form a two-dimensional hyperspectral light beam; the imaging objective lens is used to receive the linear interference light beam, modulate the linear interference light beam into a parallel light beam, and project it onto the slit; the high-resolution imaging camera is used to image the two-dimensional hyperspectral light beam and output a two-dimensional hyperspectral image.

8. The reflection-type line-scanning hyperspectral on-line measurement system based on a flashing light source according to claim 7, wherein: The single acquisition time window of the high-resolution hyperspectral spectroscopic imaging module includes the single pulse time window of the high-speed flashing line illumination light source; the continuous acquisition period of the high-resolution hyperspectral spectroscopic imaging module is consistent with the flashing period of the high-speed flashing line illumination light source, and is used to continuously acquire the interference light beam after irradiating the sample to be measured at each flashing moment.

9. The reflection type line-scanning hyperspectral online measurement system based on a flashing light source according to claim 5, characterized in that: The on-line film thickness data monitoring module includes a line-scan spectral data processing unit and a thin film detection on-line interaction unit; the line-scan spectral data processing unit is used to perform spectral frequency analysis or modeling curve fitting on the full-frame three-dimensional hyperspectral data obtained by the measurement system in real time, so as to calculate and obtain the on-line detection results of the full-frame film thickness and film thickness non-uniformity at a set spatial resolution; the thin film detection on-line interaction unit is used to display the on-line detection results of the full-frame film thickness and film thickness non-uniformity at a set spatial resolution calculated by the line-scan spectral data processing unit in real time.

10. A reflection-type line-scanning hyperspectral on-line measurement method based on a flashing light source, characterized in that: The measurement method measures the film thickness by using the reflection type line-scan hyperspectral on-line measurement system based on a flashing light source described in any one of claims 1-9.

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