阅读说明：本技术 片材制作装置以及片材制作方法 (Sheet manufacturing apparatus and sheet manufacturing method ) 是由 壁谷泰宏 本间航也 于 2021-05-19 设计创作，主要内容包括：本公开提供片材制作装置以及片材制作方法,片材制作装置(1)将涂覆材料涂覆到片材材料(11)来制作多层片材。片材制作装置(1)具备：放射光源,射出放射光；分割部,将放射光分割成入射到多层片材的测定光和照射到参照面的参照光；和光学部件,向多层片材射出测定光,并且入射由多层片材反射后的测定光。片材制作装置(1)还具备：干涉检测部,检测由多层片材反射后的测定光和由参照面反射后的参照光的干涉光；和厚度计算部(62),基于检测到的干涉光来计算多层片材的片材材料(11)以及涂覆材料的厚度。由此,能够缩短从多层片材的制作到厚度的计算的节拍时间。(The present disclosure provides a sheet manufacturing apparatus and a sheet manufacturing method, wherein the sheet manufacturing apparatus (1) applies a coating material to a sheet material (11) to manufacture a multilayer sheet. A sheet manufacturing device (1) is provided with: a radiation light source that emits radiation light; a dividing section that divides the radiated light into measurement light incident on the multilayer sheet and reference light irradiated to a reference surface; and an optical member that emits measurement light to the multilayer sheet and receives the measurement light reflected by the multilayer sheet. The sheet manufacturing device (1) further comprises: an interference detection unit that detects interference light of the measurement light reflected by the multilayer sheet and the reference light reflected by the reference surface; and a thickness calculation section (62) that calculates the thickness of the sheet material (11) and the coating material of the multilayer sheet based on the detected interference light. This can shorten the tact time from the production of the multilayer sheet to the calculation of the thickness.)

1. A sheet manufacturing apparatus that applies a coating material to a conveyed sheet material to manufacture a multilayer sheet, the sheet manufacturing apparatus comprising:

a radiation light source that emits radiation light;

a dividing section that divides the radiated light into measurement light incident on the multilayer sheet and reference light irradiated to a reference surface;

an optical member that emits the measurement light to the multilayer sheet and that receives the measurement light reflected by the multilayer sheet;

an interference detection unit that detects interference light obtained by interference between the measurement light reflected by the multilayer sheet and the reference light reflected by the reference surface; and

a thickness calculating section that calculates thicknesses of the sheet material and the coating material of the multilayer sheet based on the detected interference light.

2. The sheet producing apparatus according to claim 1,

further provided with: an inspection roller provided so as to be in contact with the multilayer sheet on a side opposite to the optical member with the multilayer sheet interposed therebetween,

the inspection roller is disposed such that a center axis of the inspection roller is parallel to a width direction of the multilayer sheet,

the optical member is configured to emit the measurement light toward an arc surface of the inspection roller that contacts the multilayer sheet.

3. The sheet producing apparatus according to claim 2,

the optical member is configured to make the measurement light perpendicularly incident on the arc surface.

4. The sheet producing apparatus according to claim 1,

further provided with:

an applicator that applies the coating material to the sheet material; and

a winding roller that winds the multilayer sheet,

the optical member is configured to emit the measurement light to the multilayer sheet positioned between the applicator and the winding roll.

5. The sheet producing apparatus according to any one of claims 1 to 4,

further provided with: a distribution acquisition section that acquires an intensity distribution of the interference light obtained by controlling the optical member to move an incident position of the measurement light in a width direction of the multilayer sheet at a given position in a length direction of the multilayer sheet,

the thickness calculation section calculates the thickness of the sheet material and the coating material based on the intensity distribution of the interference light.

6. The sheet producing apparatus according to claim 5,

the distribution acquisition section acquires intensity distributions of the interference light at a plurality of positions in a longitudinal direction of the multilayer sheet,

the thickness calculation section calculates the thickness of the sheet material and the coating material based on a result of averaging a plurality of the intensity distributions.

7. The sheet producing apparatus according to claim 6,

the distribution acquisition unit acquires an intensity distribution of the first interference light at a first position in a longitudinal direction of the multilayer sheet, and then acquires an intensity distribution of the second interference light at a second position ahead of the first position in a conveyance direction of the multilayer sheet.

8. The sheet producing apparatus according to claim 6,

the distribution acquisition unit acquires an intensity distribution of the first interference light at a first position in a longitudinal direction of the multilayer sheet, and then acquires an intensity distribution of the second interference light at a second position that is rearward in a conveyance direction of the multilayer sheet with respect to the first position.

9. The sheet producing apparatus according to claim 8,

the distance between the first position and the second position is the same as the distance over which the multilayer sheet is conveyed from the start of incidence of the measurement light to the first position to the start of incidence of the measurement light to the second position.

10. The sheet producing apparatus according to any one of claims 1 to 9,

further provided with: and a thickness adjustment unit that adjusts at least one of the thickness of the sheet material and the thickness of the coating material based on the thicknesses of the sheet material and the coating material.

11. The sheet producing apparatus according to any one of claims 1 to 10,

the emitted light is infrared light.

12. The sheet producing apparatus according to any one of claims 1 to 10,

the radiation light source emits radiation light with a wavelength within the range of 1550nm +/-100 nm and changing periodically.

13. The sheet producing apparatus according to any one of claims 1 to 10,

the radiation light source emits radiation light including light of a plurality of wavelengths in a range of 1550nm ± 100 nm.

14. The sheet producing apparatus according to any one of claims 1 to 13,

further provided with: and a determination unit that determines whether or not the multilayer sheet is acceptable based on the sheet material and the thickness of the coating material.

15. A sheet manufacturing method of applying a coating material to a conveyed sheet material to manufacture a multilayer sheet, the sheet manufacturing method comprising:

emitting radiant light from a radiant light source;

a step of dividing the radiated light into measurement light and reference light;

emitting the measurement light to the multilayer sheet through an optical member, and causing the measurement light reflected by the multilayer sheet to enter the optical member;

irradiating the reference light to a reference surface;

detecting interference light obtained by interference of the measurement light reflected by the multilayer sheet and the reference light reflected by the reference surface; and

a step of calculating the thickness of the sheet material and the coating material of the multilayer sheet based on the detected interference light.

Technical Field

The present disclosure relates to a sheet manufacturing apparatus and a sheet manufacturing method.

Background

In a belt-shaped laminated sheet including a plurality of layers, inspection of the thickness of the laminated sheet is important in terms of their characteristics. As an apparatus for inspecting the thickness of a laminated sheet, for example, japanese patent laying-open No. 5-185022 (hereinafter referred to as "patent document 1") discloses an apparatus as shown in fig. 10.

The device for inspecting the thickness of the laminated sheet described in patent document 1 includes a doctor blade 92 provided at a position closer to the conveyance target side of the metal plate 91 than the position where the resin 90 is applied, and controls the thickness of the applied resin 90. Further, the apparatus includes an X-ray thickness meter 93 provided at a position closer to the conveyance target side of the metal plate 91 than the position where the resin 90 is applied. Then, the apparatus of patent document 1 first measures the thickness of the metal plate 91 by the X-ray thickness meter 93. Then, the arithmetic unit 94 advances and retreats the scraper 92 with respect to the metal plate 91 in accordance with the measured deviation of the plate thickness of the metal plate 91. Thereby, the unevenness in the film thickness of the resin 90 applied to the metal plate 91 is reduced.

However, in the technique of patent document 1, the thickness of the laminated sheet after the resin 90 is applied is not checked. Thus, there is a fear that a laminated sheet of a desired thickness cannot be manufactured. Therefore, a configuration may be considered in which the X-ray thickness meter 93 is provided at a position closer to the conveyance target side of the metal plate 91 than the position where the resin 90 is applied, and the thickness of the laminated sheet is inspected using the X-ray thickness meter 93. However, in such a configuration, the laminated sheet needs to be sandwiched between the front and back surfaces by the X-ray irradiation unit and the detection unit of the X-ray thickness gauge 93. Further, the above device requires a cover for explosion prevention and the like. Therefore, the installation location of the X-ray thickness gauge 93 is limited. That is, the coating position and the inspection position of the resin are physically distant. As a result, the tact time from the application of the resin to the obtaining of the thickness of the laminated sheet may become long.

Disclosure of Invention

The present disclosure provides a sheet manufacturing apparatus and a sheet manufacturing method capable of shortening the tact time from the start of manufacturing a multilayer sheet to the end of calculating the thickness.

The sheet manufacturing apparatus of the present disclosure is a sheet manufacturing apparatus that applies a coating material to a conveyed sheet material to manufacture a multilayer sheet. The sheet manufacturing device is provided with: a radiation light source that emits radiation light; a dividing section that divides the radiated light into measurement light incident on the multilayer sheet and reference light irradiated to a reference surface; and an optical member that emits measurement light to the multilayer sheet and receives the measurement light reflected by the multilayer sheet. Further, the sheet manufacturing apparatus includes: an interference detection unit that detects interference light obtained by interference between the measurement light reflected by the multilayer sheet and the reference light reflected by the reference surface; and a thickness calculating section for calculating the thickness of the sheet material and the coating material of the multilayer sheet based on the detected interference light.

Further, the sheet production method of the present disclosure is a sheet production method of producing a multilayer sheet by applying a coating material to a conveyed sheet material. The sheet manufacturing method comprises the following steps: emitting radiant light from a radiant light source; a step of dividing the emitted light into measurement light and reference light; and a step of emitting measurement light to the multilayer sheet through the optical member, and causing the measurement light reflected by the multilayer sheet to enter the optical member. Further, the sheet manufacturing method includes: irradiating the reference surface with reference light; detecting interference light obtained by interference of the measurement light reflected by the multilayer sheet and the reference light reflected by the reference surface; and a step of calculating the thickness of the sheet material and the coating material of the multilayer sheet based on the detected interference light.

According to the present disclosure, it is possible to provide a sheet manufacturing apparatus and a sheet manufacturing method capable of shortening the tact time from the start of manufacturing a multilayer sheet to the end of calculating the thickness of the multilayer sheet.

Drawings

Fig. 1 is a schematic diagram illustrating a schematic configuration of a sheet manufacturing apparatus in embodiment 1 of the present disclosure.

Fig. 2 is a schematic diagram showing the structure of the SS-OCT apparatus in embodiment 1 and embodiment 2 of the present disclosure.

Fig. 3 is a flowchart illustrating a sheet manufacturing method in embodiment 1.

Fig. 4A is a YZ plan view illustrating a positional relationship between the objective lens and the multilayer sheet of the SS-OCT apparatuses in embodiment 1 and embodiment 2.

Fig. 4B is an XY plan view showing a positional relationship between the inspection roller and the multilayer sheet of the SS-OCT apparatuses in embodiment 1 and embodiment 2.

Fig. 5A is a schematic diagram illustrating a positional relationship between the measurement light and the multilayer sheet in the case where B-scanning is performed at the same B-scanning position on the multilayer sheet, but different on the inspection roller in embodiment 1 and embodiment 2.

Fig. 5B is a schematic diagram illustrating a positional relationship between the measurement light and the multilayer sheet in the case where B-scanning is performed at a B-scanning position that is different on the inspection roller and also different on the multilayer sheet in embodiment 1 and embodiment 2.

Fig. 5C is a schematic view showing a positional relationship between the measurement light and the multilayer sheet in the case where B-scanning is performed at the same B-scanning position on the inspection roller and at different B-scanning positions on the multilayer sheet in the state where the conveyance speed of the multilayer sheet is lowered in embodiment 1 and embodiment 2.

Fig. 6A is a cross-sectional view of a YZ plane illustrating a periodic configuration of sheet materials in the multilayer sheet in embodiment 1 and embodiment 2.

Fig. 6B is an XY plan view showing a positional relationship between the inspection roller and the multilayer sheet of the SS-OCT apparatuses in embodiment 1 and embodiment 2.

Fig. 6C is an XY plan view showing a periodic structure of the sheet material in the multilayered sheet in embodiment 1 and embodiment 2.

Fig. 7A is a schematic view showing the refractive state of measurement light in the multilayered sheets in embodiment 1 and embodiment 2.

Fig. 7B is an explanatory diagram of a method of calculating the thickness of the multilayered sheet in embodiment 1 and embodiment 2.

Fig. 8 is a schematic diagram showing a schematic configuration of a sheet manufacturing apparatus in embodiment 2.

Fig. 9 is a flowchart illustrating a sheet manufacturing method in embodiment 2.

Fig. 10 is an explanatory diagram of the conventional technique described in patent document 1.

Detailed Description

Embodiments of the present disclosure will be described with reference to the drawings.

(embodiment mode 1)

Hereinafter, a sheet manufacturing apparatus according to embodiment 1 of the present disclosure will be described in sections.

< schematic configuration of sheet Forming apparatus >

First, a schematic configuration of a sheet forming apparatus 1 according to embodiment 1 of the present disclosure will be described with reference to fig. 1.

Fig. 1 is a schematic view of a sheet manufacturing apparatus 1 in embodiment 1 of the present disclosure. In the following, directions will be described with reference to XYZ axes shown in fig. 1. Specifically, the Y-axis corresponds to the longitudinal direction or the conveying direction of the sheet material 11 or the multilayer sheet 10. The X axis corresponds to a direction orthogonal to the width direction or the conveying direction of the sheet material 11 or the multilayer sheet 10.

The sheet production apparatus 1 is an apparatus for producing a multilayer sheet 10 in which a sheet material 11 is coated with a coating material 12 (see fig. 6A) and inspecting the multilayer sheet 10.

Specifically, as shown in fig. 1, the sheet forming apparatus 1 according to embodiment 1 includes a sheet supply reel 20, a coating section 30, a winding roll 40, an SS-OCT apparatus 50, a sheet generation control section 60, and the like. In addition, the above SS-OCT is an abbreviation of Swept-Source Optical Coherence Tomography (wavelength scanning type Optical Coherence Tomography).

The rotation axis of the sheet supply reel 20 is provided parallel to the X axis. The sheet material 11 wound in a roll shape is attached to the sheet supply reel 20. The sheet supply reel 20 supplies the sheet material 11 to the coating section 30. The sheet material 11 is a base material of the multilayer sheet 10, and is, for example, a sheet made of resin such as cellophane resin or polyimide resin, or a cloth or nonwoven fabric woven from cotton, resin fibers, or glass fibers.

The coating section 30 includes a coating roller 31, a coating feeder 32, a coating applicator 33, and the like.

The coating roller 31 is disposed on the sheet material 11 conveyance direction side (-Y direction side) of the sheet supply reel 20, and has a rotation axis parallel to the X axis.

The coating feeder 32 feeds the coating material 12 to the coating applicator 33. The coating material 12 is, for example, an adhesive made of a resin such as epoxy or acrylic, or a filler coated for the purpose of reinforcing the mechanical strength of the fiber and improving the weather resistance.

The applicator 33 is disposed above the application roller 31 (the (-Z direction side). The applicator 33 applies the coating material 12 fed from the coating feeder 32 to the sheet material 11 conveyed on the coating roller 31. Thus, the coating material 12 is laminated on the sheet material 11 to form the multilayer sheet 10. The multilayer sheet 10 is an example of an object to be measured. Specifically, the multilayered sheet 10 is, for example, an adhesive tape.

In addition, the method of applying the coating material 12 to the sheet material 11 is not limited to the method using the applicator 33. For example, the coating material 12 may be applied to the sheet material 11 by passing the sheet material 11 through a tank filled with the coating material 12. Further, the coating material 12 may also be applied to the sheet material 11 by bringing another roller coated with the coating material 12 into contact with the sheet material 11. Further, the coating material 12 may be applied to both surfaces of the sheet material 11.

In the above description, the multilayer sheet 10 has been described by taking a structure including 2 layers of the base material and the resin layer as an example, but is not limited thereto. For example, the multilayer sheet 10 may be configured by a multilayer structure formed of a plurality of coating layers and a plurality of base materials. In forming the multilayer sheet 10, a drying step of the coating material 12 by a heater, hot air, or the like may be provided after the coating of the coating material 12 on the sheet material 11 described later.

The winding roller 40 of the sheet forming apparatus 1 is disposed on the feeding direction side (-Y direction side) of the sheet material 11 with respect to the applicator 33, and the rotation axis is parallel to the X axis. The winding roller 40 is driven by a motor or the like to rotate, thereby winding the multilayer sheet 10. In the above description, the example of the step of winding the multilayer sheet 10 by the winding roll 40 is described, but the invention is not limited thereto. For example, a sheet-like cutting step of cutting the sheet into a predetermined length may be provided without the step of winding. Further, the multilayer sheet 10 may be continuously connected in a subsequent step without providing a winding step.

The SS-OCT apparatus 50 of the sheet forming apparatus 1 outputs various information used for calculating the thicknesses of the sheet material 11 and the coating material 12 constituting the multilayer sheet 10 to the sheet generation control unit 60. In addition, the detailed structure of the SS-OCT apparatus 50 is described later.

The sheet generation control unit 60 includes an operation control unit 61, a thickness calculation unit 62, a determination unit 63, a storage unit 64, a display unit 65, and the like, and controls the operation of the entire sheet forming apparatus 1.

The operation control section 61 controls the operation of producing the multilayer sheet 10.

The thickness calculation section 62 calculates the thickness of the sheet material 11 and the coating material 12 based on the information from the SS-OCT apparatus 50.

The determination unit 63 determines whether the multilayer sheet 10 is acceptable (OK or NG) based on the calculation result of the thickness calculated by the thickness calculation unit 62.

The storage unit 64 stores the NG-quality multilayer sheet 10 in association with a manufacturing number or the like given to the multilayer sheet 10.

The display unit 65 displays whether the multilayer sheet 10 is OK or NG based on the determination result of the determination unit 63.

< for SS-OCT apparatus >

Next, the structure of the SS-OCT apparatus 50 will be described with reference to fig. 2. Fig. 2 is a schematic diagram showing the structure of the SS-OCT apparatus.

In addition, the SS-OCT apparatus 50 is an example of an inspection apparatus. The SS-OCT apparatus 50 is an Optical interference signal measuring apparatus using wavelength scanning Optical Coherence Tomography (SS-OCT: Swept Source-Optical Coherence Tomography).

Further, OCT (Optical Coherence Tomography) is a measurement method using interference of light. Specifically, the OCT splits the radiation light from the light source into the reference light and the measurement light L, and causes the reference light to enter the reference surface and the measurement light L to enter the measurement object. Then, the reference light reflected by the reference surface and the measurement light L reflected by the measurement object are interfered with each other to detect an interference signal. Then, the OCT detects the position of the measurement target based on the detected interference signal.

In OCT, there are 2 kinds of Time Domain OCT (TD-OCT: Time Domain Optical Coherence Tomography) requiring scanning of a reference surface and frequency Domain OCT (FD-OCT: Fourier Domain Optical Coherence Tomography) not requiring scanning of a reference surface. Further, among FD-OCT, there are 2 types of a spectroscope type and a wavelength scanning type. In particular, the wavelength-scanning type FD-OCT is referred to as the above-mentioned SS-OCT. The SS-OCT detects interference light while changing the frequency of light emitted from a light source with time.

The SS-OCT apparatus 50 includes an inspection roller 51, a measurement head 52, a fiber interferometer 53, and the like.

The inspection roller 51 is disposed between the coating roller 31 and the winding roller 40 with the rotation axis parallel to the X-axis. The inspection roller 51 is disposed to hold the multilayered sheet 10 in contact at the angle α. Therefore, the surface of the inspection roller 51 in contact with the multilayer sheet 10 is an arc surface 511.

The measuring head 52 functions as an example of an optical member. The measurement head 52 includes an irradiation collimator lens 521, a galvanometer mirror pair 522, an objective lens 523, a driving unit 524, and the like. The galvanometer mirror pair means a pair of galvanometers, and the same applies hereinafter.

The irradiation collimator lens 521 is connected to a second circulator 536 of the fiber interferometer 53 described later. The irradiation collimator lens 521 collimates the measurement light L incident from the second circulator 536. The parallel light is emitted to the galvanometer mirror pair 522.

The pair of galvano mirrors 522 is disposed above the inspection roller 51. The galvanometer mirror pair 522 includes a first mirror having a rotation axis parallel to the X axis and a second mirror having a rotation axis parallel to the Y axis. The galvanometer mirror pair 522 reflects the parallel light incident from the irradiation collimator lens 521 and emits the reflected parallel light to the objective lens 523.

The objective lens 523 is disposed between the galvanometer mirror pair 522 and the inspection roller 51. The objective lens 523 condenses the parallel light incident from the galvanometer mirror pair 522 and irradiates the multilayer sheet 10. Here, the objective lens 523 is provided to constitute a telecentric optical system by combination with the galvanometer mirror pair 522. Therefore, although the incident position of the measurement light L changes in the XY plane (horizontal plane) due to the movement of the first mirror and the second mirror of the galvanometer mirror pair 522, the incident angle degree to the incident position of the measurement light L does not change.

The driving unit 524 moves the first mirror and the second mirror of the galvanometer mirror pair 522 to adjust the incident position of the measurement light L with respect to the multilayer sheet 10.

With the configuration of the measurement head 52 as described above, the measurement light L enters the irradiation collimator lens 521 from the second circulator 536. The incident measurement light L is condensed by the objective lens 523 via the galvanometer mirror pair 522 as described above, and enters the surface of the multilayer sheet 10. The measurement light L incident on the surface of the multilayer sheet 10 is reflected (or backscattered) at the surface, inside, and back surfaces of the multilayer sheet 10 and the inspection roller 51. The reflected measurement light L is emitted to the second circulator 536 via the objective lens 523, the galvanometer mirror pair 522, and the irradiation collimator lens 521.

The fiber interferometer 53 functions as an example of a light source unit. The fiber interferometer 53 includes a radiation light source 531, a first coupler 532, a first circulator 533, a reference collimator lens 534, a reference surface 535, a second circulator 536, a second coupler 537, a differential amplifier 538, an OCT arithmetic processing unit 539, and the like.

The radiation light source 531 emits radiation light. The radiation light source 531 is configured to be able to change the wavelength of the radiation light. A light emitting port of the radiation light source 531 is connected to a light receiving port of the first coupler 532.

The first coupler 532 functions as an example of a dividing section that divides the light incident from the radiation light source 531 by 2 at a fixed ratio of 50: 50, for example. The first coupler 532 has a first optical transmission port and a second optical transmission port, not shown. The first optical sending-out port is connected to the first circulator 533. The second light transmitting port is connected to the second circulator 536. With this configuration, the radiant light incident on the first coupler 532 from the radiant light source 531 is split into the reference light and the measurement light L. The reference light is emitted to the first circulator 533, and the measurement light L is emitted to the second circulator 536.

The first circulator 533 is connected to the light-receiving port of the second coupler 537. The first circulator 533 emits the reference light incident from the first coupler 532 to the reference collimating lens 534. The reference light incident on the reference collimator lens 534 is reflected by the reference surface 535, and is emitted to the first circulator 533 via the reference collimator lens 534. The first circulator 533 emits the reference light reflected by the reference surface 535 to the second coupler 537.

The second circulator 536 is connected to a light-receiving port of the second coupler 537 and a light-receiving port of the measuring head 52 that irradiates the collimator lens 521. Thus, the second circulator 536 emits the measurement light L incident from the first coupler 532 to the measurement head 52, and emits the measurement light L from the measurement head 52 to the second coupler 537.

The second coupler 537 is connected to the differential amplifier 538. The second coupler 537 forms interference light based on the reference light from the first circulator 533 and the measurement light L from the second circulator 536. That is, the second coupler 537 functions as an example of a multiplexing unit of the reference light and the measurement light L.

The differential amplifier 538 differentially transmits the optical pickup signal of the interference light formed by the second coupler 537 to the OCT arithmetic processing unit 539. At this time, the frequency of the radiant light emitted from the radiant light source 531 changes with time. Therefore, a frequency difference corresponding to the time delay amount is generated between the reference light and the measurement light L that interfere with each other in the second coupler 537. This frequency difference becomes an optical beat signal of the interference light.

The OCT processing unit 539 includes an analog/digital conversion circuit 539A (analog/digital conversion unit), a fourier conversion circuit (fourier conversion unit) 539B, an operation unit 539C, and the like. The fourier transform circuit 539B functions as an interference detection unit, and the arithmetic unit 539C functions as a distribution acquisition unit.

The analog/digital conversion circuit 539A is connected to the differential amplifier 538. The analog-to-digital conversion circuit 539A converts the time waveform of the optical pickup signal of the interference light formed by the differential amplifier 538 from analog to digital.

The fourier transform circuit 539B is connected to the analog/digital transform circuit 539A. The fourier transform circuit 539B detects a light beat signal of the interference light from the analog/digital transform circuit 539A. The fourier transform circuit 539B performs fourier transform on the detected optical beat signal, and performs frequency resolution. Thereby, the fourier transform circuit 539B obtains an SS-OCT signal representing the intensity distribution of the interference light.

An input unit of the arithmetic unit 539C is connected to the fourier transform circuit 539B. The arithmetic unit 539C calculates a reflected signal intensity distribution that is an intensity distribution (Profile) of the interference light at the incident position of the measurement light L based on the information (SS-OCT signal) input from the fourier transform circuit 539B. Hereinafter, a process of acquiring a 1-dimensional reflected signal intensity distribution in the incident direction at the 1-point position where the measurement light L is incident will be described as "a-scan".

The output unit of the computing unit 539C is connected to the radiation light source 531, the driving unit 524 such as the galvanometer mirror pair 522 of the measurement head 52, and the sheet generation control unit 60 (see fig. 1). The computing unit 539C controls the driving unit 524 to operate the galvanometer mirror pair 522. Specifically, the calculation unit 539C performs the above-described a-scan while changing the incident position of the measurement light L. Thus, the calculation unit 539C acquires the reflected signal intensity distribution at the incident position of the linearly changing measurement light L, and forms a 2-dimensional image thereof. Hereinafter, a process of acquiring the reflected signal intensity distribution at the incident position of the plurality of measurement lights imaged in 2-dimension will be described as "B-scan", and the obtained 2-dimensional image will be described as "B-scan image", to be explained.

The sheet generation control unit 60 shown in fig. 1 performs a predetermined operation such as calculation of the thickness of the multilayer sheet 10 based on information obtained by the a scan or the B scan based on the control of the calculation unit 539C.

In addition, the TD-OCT described above may be employed in the above embodiment 1 and the later-described embodiment 2. However, in the case of TD-OCT, SS-OCT or SD-OCT that can be performed at 10kHz or more, for example, is preferable as the above-described 1-dimensional scan called A-scan. This can increase the speed of measuring the thickness of the multilayer sheet 10.

< installation position and scanning direction of measuring head >

Next, the installation position and the scanning direction of the measurement head 52 will be described with reference to fig. 2.

As described above, the multilayer sheet 10 contacts the outer peripheral surface of the inspection roller 51 at the holding angle α. The measuring head 52 is provided such that: within the operating range of the pair of galvanometer mirrors 522, the measurement light L can enter perpendicularly to the arcuate surface 511 of the multilayer sheet 10 in contact with the inspection roller 51. With this structure, the refraction of the measurement light L between the air and the multilayer sheet 10 can be suppressed. Therefore, the thickness of the multilayer sheet 10 can be measured more accurately.

The rotation axis of the second mirror of galvanometer mirror pair 522 is arranged parallel to the Y axis. With this configuration, the position at which the measurement light L is incident can be moved in the X-axis direction, which is the axial direction of the inspection roller 51, to perform the B-scan.

< method for producing sheet >

Next, a sheet forming method performed by the sheet forming apparatus 1 will be described with reference to fig. 3, with reference to fig. 1 and 2. Fig. 3 is a flowchart illustrating a sheet manufacturing method.

First, as shown in fig. 3, for example, the winding end portion of the sheet material 11 wound around the sheet supply reel 20 shown in fig. 1 is extended and set to the winding roller 40 (step S1). Step S1 may be performed by the operator, or may be performed automatically by providing a gripping portion for gripping the sheet material 11. As a method of setting the sheet material 11 to the winding roller 40, for example, a method of setting an openable and closable slit in the winding roller 40 and holding the sheet material 11 in the slit can be exemplified.

Next, the multilayer sheet 10 is generated (step S2). Specifically, the operation control section 61 of the sheet generation control section 60 rotates the winding roller 40 in the counterclockwise direction. At this time, the operation control section 61 feeds the coating material 12 from the coating feeder 32 to the coating applicator 33 while conveying the sheet material 11. As a method for feeding the coating material 12, for example, a pressure feed using compressed air or the like or a pump such as a diaphragm pump may be used. Thereby, the surface of the sheet material 11 is coated with the coating material 12, and the multilayer sheet 10 is produced. The resulting multilayered sheet 10 is continuously wound on a winding roll 40.

Next, the SS-OCT apparatus 50 performs the SS-OCT measurement on the multilayer sheet 10 while conveying the multilayer sheet 10 (step S3).

Here, details of the SS-OCT apparatus 50 will be specifically described.

First, the SS-OCT apparatus 50 measures the thickness of the multilayer sheet 10 while changing the wavelength of the radiant light emitted from the radiant light source 531. In this case, the range of the wavelength to be changed is, for example, 1550 nm. + -.100 nm. If the amount is within this range, the transmittance of the radiant light with respect to the sheet material 11 and the coating material 12 can be improved. The operation of the radiation light source 531 is controlled by the arithmetic unit 539C. The radiant light from the radiant light source 531 is incident on the surface of the multilayer sheet 10 from the-Z direction.

The wavelength of the radiant light emitted from the radiant light source 531 may be set to a wavelength outside the range of 1550nm ± 100 nm. This makes it possible to obtain an effect that the resolution is high when the center wavelength is shortened, and scattering from the measurement object is not easily received when the center wavelength is lengthened. In addition, the radiation light source 531 may emit radiation light including light having a plurality of wavelengths in the range of 1550nm ± 100 nm. In this case, the emission light including light of a plurality of wavelengths may be emitted by 1 light source, or a plurality of light sources capable of emitting light of mutually different wavelengths may be used. This makes it possible to easily select a wavelength to be used.

The measurement light L incident on the multilayer sheet 10 is reflected (or backscattered) by the inspection roll 51 on the front surface, inside, and back surface of the multilayer sheet 10. The measurement light L reflected by the multilayer sheet 10 proceeds toward the second coupler 537. Then, in the second coupler 537, the measurement light L reflected by the multilayer sheet 10 and the reference light reflected by the reference surface 535 interfere with each other, thereby forming interference light. The formed optical beat signal of the interference light is detected by the fourier transform circuit 539B of the OCT arithmetic processing unit 539 via the differential amplifier 538.

The arithmetic unit 539C of the OCT arithmetic processing unit 539 frequency-analyzes the optical pickup signal of the interference light detected by the fourier transform circuit 539B to acquire an SS-OCT signal. Then, the arithmetic unit 539C calculates the B-scan image based on the acquired SS-OCT signal. The calculated B-scan image is the 2-dimensional imaged reflected signal intensity distribution as described above.

Then, the B-scan image calculated by the calculation unit 539C is output to the sheet generation control unit 60 together with information on the incident position of the measurement light L. At this time, as described above, the incident position of the measurement light L in the multilayer sheet 10 is in contact with the inspection roller 51. Therefore, the incident position of the measurement light L is stabilized against vibration and the like. As a result, the multilayer sheet 10 can be inspected (measured) with high accuracy, for example, in terms of thickness.

In the OCT apparatus, when infrared light having a wavelength of 1550nm ± 100nm is used as the measurement light L (radiation light) as described above, the measurement light L can pass through the resin. When the measurement light L passes through the resin, scattered light is generated inside the resin due to additives such as fillers inside the resin and unevenness in refractive index inside the resin. Moreover, the generated scattered lights are intensified with each other, generating a random speckle pattern. This speckle pattern is not preferable because it affects the calculation of the thickness Δ Zs and the thickness Δ Zt in step S4 described later.

Therefore, in the processing of step S3, the thickness calculation unit 62 of the sheet generation control unit 60 emits the measurement light L from at least a plurality of angles with respect to the multilayer sheet 10 and performs B-scanning. Then, the thickness calculation unit 62 acquires a plurality of B-scan images having different speckle generation patterns, and averages the B-scan images. Thereby, an averaged image from which the spots are removed is obtained. In addition, the averaging process is described later.

Next, as shown in fig. 3, the thickness calculation section 62 of the sheet generation control section 60 calculates the thickness Δ Zs of the sheet material 11 and the thickness Δ Zt of the coating material 12 based on the averaged image obtained as described above (step S4). Further, specific explanation of the calculation of the thickness Δ Zs and the thickness Δ Zt will be described later.

Next, the determination unit 63 determines whether or not the thickness Δ Zs and the thickness Δ Zt calculated in step S4 are within the OK range (step S5). The OK range is a range in which a product can be regarded as a non-defective product. Specifically, the OK range is a range of the thickness Δ Zs and the thickness Δ Zt that have no problem in quality. The OK range is stored in the storage unit 64 in advance. In addition, details of the OK range stored in advance are described later.

At this time, when the determination unit 63 determines that the thicknesses Δ Zs and Δ Zt are not within the OK range (outside the OK range) (no in step S5), an NG signal is output to the display unit 65 (step S6). Then, the display section 65 displays that the formed multilayer sheet 10 is NG based on the NG signal (step S7). Further, the determination unit 63 establishes a product relationship between the manufacturing number and the like indicated on the multilayered sheet 10 and information indicating NG, and stores the information in the storage unit 64 (step S8). This makes it possible to more reliably discard NG products by collating the information stored in the storage unit 64 and the manufacturing number of the multilayer sheet 10 with each other in the subsequent step.

On the other hand, when the determination unit 63 determines that the thicknesses Δ Zs and Δ Zt are within the OK range (yes in step S5), the operation control unit 61 determines whether or not the multilayer sheet 10 is completed (step S9). In this case, the operation control section 61 determines whether or not the multilayer sheet 10 is completed based on information from an encoder or the like connected to the winding roller 40. Specifically, for example, the operation control section 61 first determines the number of rotations of the winding roller 40 based on information from the encoder. Then, it is determined whether or not the obtained number of rotations reaches the number previously stored in the storage unit 64. The number of times stored in advance is, for example, 10 times.

At this time, if the operation control section 61 determines that the multilayer sheet 10 is not completed (for example, less than 10 times) (no in step S9), the operation control section returns to step S3 without completing the production of the multilayer sheet 10, and performs the SS-OCT measurement again.

On the other hand, when it is determined that the multilayer sheet 10 is completed (yes in step S9) or when the process of step S8 is performed, the operation control section 61 ends the coating operation of the coating device 33. Then, the sheet material 11 is cut by a cutting unit (not shown) from the sheet supply reel 20 to the coating roller 31 (step S10), and the sheet forming operation of the multilayer sheet 10 is terminated.

When steps S7 and S8 are performed, step S10 may be performed simultaneously. This can minimize the NG range of the multilayer sheet.

Further, the above-described steps S3 to S5 are one example of the checking step. That is, in embodiment 1, the inspection step is performed simultaneously with the production of the multilayer sheet 10. This can shorten the time required from the start of production of the multilayer sheet 10 to the end of the inspection.

< position of measurement light in Y direction in averaging processing of a plurality of B-scan images >

Next, the position of the measurement light in the Y direction in the averaging process of the plurality of B-scan images in step S3 shown in fig. 3 will be described with reference to fig. 4A to 5C.

Fig. 4A is a YZ top view illustrating a positional relationship of the objective lens 523 of the SS-OCT apparatus 50 and the multilayer sheet 10. Fig. 4B is an XY plan view showing the positional relationship of the inspection roller 51 of the SS-OCT apparatus 50 and the multilayer sheet 10. Fig. 5A is a schematic diagram illustrating the positional relationship of the measurement light L and the multilayer sheet 10 in the case where B-scanning is performed at the same B-scanning position on the multilayer sheet 10, but different on the inspection roller 51. Fig. 5B is a schematic diagram illustrating the positional relationship between the measurement light L and the multilayer sheet 10 in the case where B-scanning is performed at a B-scanning position that is different on the inspection roller 51 and also different on the multilayer sheet 10. Fig. 5C is a schematic diagram showing the positional relationship between the measurement light L and the multilayer sheet 10 when B-scanning is performed at the same B-scanning position on the inspection roller 51 and at different B-scanning positions on the multilayer sheet 10 in a state where the conveyance speed of the multilayer sheet 10 is lowered.

Here, if there is a variation in thickness in the surface of the multilayer sheet 10 when averaging a plurality of B-scan images, the more different the position of the B-scan corresponding to the B-scan image, the more different the speckle generation pattern. In this case, different from the above-described averaging of the same region, B-scan images of different regions are averaged with each other. Therefore, the calculation accuracy of the thickness Δ Zs and the thickness Δ Zt performed in step S4 becomes low.

The positional relationship between the measurement light L and the multilayer sheet 10 in fig. 5A to 5C will be specifically described below in the section (A, B, C).

(A: averaging of B-scan images obtained by B-scanning at B-scan positions different on the inspection roller and the same on the multi-layered sheet (surface))

In embodiment 1 and embodiment 2 described later, as shown in fig. 5A, the B-scan position on the inspection roller 51 is shifted by a predetermined shift amount in parallel with the Y-direction, which is the conveyance direction of the multilayer sheet 10. Further, B-scan is performed under the same conditions with respect to the same B-scan position of the surface of the multilayered sheet 10 as viewed from the multilayered sheet 10, thereby acquiring a B-scan image. The shift amount is determined by the thickness calculation unit 62 of the sheet generation control unit 60 based on the conveyance speed of the multilayer sheet 10.

Here, as shown in fig. 4A and 4B, the radius of the inspection roller 51 is defined as r, and a line passing through the center of the inspection roller 51 and extending in the gravity direction is defined as a center line C. Further, an angle formed by a line connecting a position on the inspection roller 51 where the measurement light L is incident and the center of the inspection roller 51 at the time of the first B scan and a gravity direction (center line C) parallel to the Z axis is θ 1, and a distance along the horizontal direction (Y direction) from the first B scan position 51A as the first interference light at the first position to the center line C is X1. In addition, hereinafter, the position is sometimes described as "first B scanning position 51A".

In this case, the radius r, the angle θ 1, and the distance X1 satisfy the following formula (1).

X1＝r×cosθ1 (1)

At this time, if the positional relationship between the inspection roller 51 and the measurement head 52 is fixed, the distance X1 is a known value, and thus the angle θ 1 is also a known value.

Further, let Δ θ be the rotation angle of the inspection roller at the time interval of the B-scan, and let X2 be the distance along the horizontal direction (Y direction) from the position on the inspection roller 51 where the measurement light L is incident at the time of the second B-scan to the center line C. In addition, hereinafter, the above-described position is sometimes described as "second B scanning position 51B" as the second interference light at the second position.

In this case, the radius r, the angle θ 1, the angle Δ θ, and the distance X2 satisfy the following expression (2).

X2＝r×coS(θ1+Δθ) (2)

Therefore, the thickness calculation unit 62 controls the drive unit 524 to operate the galvanometer mirror pair 522 so that the first B scanning position 51A is a position satisfying the expression (1) and the second B scanning position 51B is a position satisfying the expression (2).

In this case, the 2B-scan images obtained by the first B-scan and the second B-scan are images indicating different B-scan positions on the inspection roller 51.

That is, as shown in fig. 5A, when viewed from the multilayer sheet 10, the measurement light L on the multilayer sheet 10 (front surface) is an image having the same incident position and different incident angles. Further, due to the effect of the multilayer sheet 10 being bent along the arc surface 511 of the inspection roller 51, the incident angle of the measurement light L1 in the first B-scan becomes θ 1, and the incident angle of the measurement light L2 in the second B-scan becomes θ 2. Thus, the generation pattern of the spots of the 2B-scan images is different. Thus, different 2B-scan images are averaged. This enables removal of spots. Further, since the same measurement position is maintained in the multilayer sheet 10, the calculation accuracy of the thickness Δ Zs and the thickness Δ Zt performed in step S4 shown in fig. 3 is not degraded.

On the other hand, if the first and second B-scans are performed under the same conditions as described above for a portion of the multilayer sheet 10 that is conveyed linearly without curving along the inspection roller 51 (for example, a portion located between the inspection roller 51 and the application roller 31), the incident angles of the measurement light in the 2B-scan images are equal to each other. Thus, the resulting pattern of spots is also equal. As a result, even if the obtained 2B-scan images are averaged, the spots cannot be removed. That is, a structure in which a B-scan image is obtained at the portion of the multilayer sheet 10 described above is not preferable.

The movement of the B-scan position can be performed by changing the angle of the galvanometer mirror pair 522, but is not limited thereto. Instead of using the galvanometer mirror pair 522, for example, a mechanism such as a stepping motor may be provided to move the measurement head 52 itself. This can provide the same effect without using an expensive galvanometer mirror.

(B: averaging of B-scan images obtained by B-scanning at B-scan positions which are different on the inspection roller and also different on the multi-layer sheet (surface))

In addition, when there is no variation in the in-plane thickness of the multilayer sheet 10, the incidence positions of the measurement light in the plurality of B scans may be largely different. In this case, the incident position of the measurement light is more preferably shifted by not less than the spot size of the measurement light. This can improve the effect of removing speckles.

At this time, as shown in fig. 5B, the incident position (corresponding to the first position) of the measurement light L1 of the first B-scan in the multilayer sheet 10 is set to be located rearward in the conveyance direction of the multilayer sheet 10 with respect to the incident position (corresponding to the second position) of the measurement light L2 of the second B-scan. This can suppress the amount of change in the angle of the galvanometer mirror pair 522 and generate a large difference in the position of the measurement light. Further, the incidence of the measurement light L1 and the incidence of the measurement light L2 on the same site can be reliably avoided. This is more preferable because a large difference can be created in the generation pattern of the spots.

Further, the incident position (corresponding to the second position) of the measurement light L2 of the second B-scan may be positioned forward in the conveyance direction of the multilayer sheet 10 with respect to the incident position (corresponding to the first position) of the measurement light L1 of the first B-scan. With this configuration, the same portion of the multilayer sheet 10 can be measured using the measurement light incident from different angles.

Preferably, the distance between the incident position of the measurement light L1 of the first B-scan and the incident position of the measurement light L2 of the second B-scan is the same as the distance over which the multilayer sheet 10 is conveyed from the start of the incidence of the measurement light L1 of the first B-scan to the start of the incidence of the measurement light L2 of the second B-scan. With this configuration, the measurement light can be incident on the same portion during conveyance of the multilayer sheet 10, and the positions of the B-scans can be made the same. This makes it possible to average the B-scan images of the same region. As a result, the accuracy of calculating the thickness Δ Zs and the thickness Δ Zt in step S4 shown in fig. 3 can be suppressed from decreasing.

As described above, when the first B-scan and the second B-scan are performed, in the case shown in fig. 5A, the incidence angles of the measurement light are different but the incidence positions are the same in the multilayer sheet 10. On the other hand, in the case shown in fig. 5B, the incidence angle (the incidence angle θ 1 ≠ of the measurement light L1 in the first B-scan) and the incidence position of the measurement light L2 in the second B-scan) are different from each other.

(C: averaging of B-scan images obtained by B-scanning at the same B-scan position on the inspection roller and different B-scan positions on the multi-layer sheet (surface))

In general, even when there is no variation in the in-plane thickness of the multilayer sheet 10, B-scanning is continued at the same position in the inspection roller 51, and spots may not be sufficiently removed due to the following situation or the like, which is not preferable.

For example, the multilayer sheet 10 may be momentarily stopped during conveyance or the conveyance speed may be reduced due to slack of the multilayer sheet 10 caused by disturbance or tension variation. In this case, the incident positions of the measurement lights may be the same or extremely close to each other. Therefore, the possibility arises that spots cannot be sufficiently removed, and this is not preferable.

In the case of the above situation, as shown in fig. 5C, the incident angle of the measurement light L1 of the first B-scan and the incident angle of the measurement light L2 of the second B-scan in the multilayered sheet 10 become the same. Therefore, the difference between the incident positions of the measurement light L1 and the measurement light L2 is a length obtained by multiplying the time interval of each B scan by the transport speed. That is, if the conveyance speed is in the vicinity of 0 (zero) due to a variation in tension or the like, the same speckle pattern is generated in the first B-scan and the second B-scan, which is not preferable in the averaging process of the B-scan image.

Note that A, B, C described above is an example of averaging 2B-scan images, but is not limited to this. For example, a plurality of B-scan images of 2 or more may be averaged. This increases the measurement tact time, but enables stronger removal of the speckle pattern.

< position of measurement light in Y direction in averaging processing of a plurality of B-scan images of a multilayer sheet having a structure that is not uniform in X direction >

Next, description is made using fig. 6A to 6C: in the averaging process of the plurality of B-scan images in step S3 shown in fig. 3, the position in the Y direction of the measurement light in the averaging process of the B-scan images of the multilayer sheet 10 having a structure that is not uniform in the X direction (web direction).

Fig. 6A is a cross-sectional view of the YZ plane illustrating the periodic configuration of the sheet material 11 in the multilayer sheet 10. Fig. 6B is an XY plan view showing the positional relationship of the inspection roller 51 of the SS-OCT apparatus 50 and the multilayer sheet 10. Fig. 6C is an XY plan view showing the periodic configuration of the sheet material 11 in the multilayer sheet 10.

That is, even if the Y-direction position in the multilayer sheet 10 is the same, different B-scan images may be obtained depending on the X-direction position.

Therefore, as shown in fig. 6A, a case where a periodic uneven structure is provided along the X direction on the surface of the sheet material 11 is considered below in order to improve the adhesion with the coating material 12.

Specifically, as shown in fig. 6B, a case is considered in which B-scan images at a first B-scan position 51C and a second B-scan position 51D along a line parallel to the X direction and at different positions in the Y direction are obtained. In this case, if the phase of the periodic structure in the X direction of the sheet material 11 is always constant regardless of the position in the Y direction, the periodic structure in the X direction in the B-scan image is also constant regardless of the measurement position (the first B-scan position 51C and the second B-scan position 51D).

However, generally, as for the conveying direction of the sheet material 11, as long as a device such as EPC (edge position controller) is not used, a specific phase portion of the periodic structure (for example, a peak portion of the periodic structure) does not exist as if it exists along the conveying direction. That is, as shown in fig. 6C, the specific phase portion P of the periodic structure may be inclined in the θ z direction by an angle θ s with respect to the conveying direction.

In this case, even if the averaging process is performed by directly using the B-scan images at the first B-scan position 51C and the second B-scan position 51D, the spots can be removed because the incidence positions of the measurement light are different. However, since the periodic configuration of the sheet material 11 in the 2B-scan images is different, the image obtained by the averaging process becomes unclear. Therefore, the calculation accuracy of the thickness Δ Zs and the thickness Δ Zt is lowered.

Therefore, the Y-direction correction is performed based on the conveyance distance of the sheet material 11 and the angle θ s. Specifically, the second B-scan position 51D is shifted in the Y direction by a distance M satisfying the following expression (3) with respect to the first B-scan position 51C based on the conveyance distance D and the angle θ s of the sheet material 11 between 2B-scans, thereby enabling measurement of the same position. This can eliminate the phase shift of the periodic structure in the 2B-scan images.

M＝D×tanθs (3)

The angle θ s may be obtained based on the phase difference in the X direction of the 2B-scan images. Further, the angle θ s may be obtained based on a result of detecting the position of the X-direction edge of the sheet material 11 by a displacement meter (not shown).

In the above description, the case where the phase in the surface structure of the sheet material 11 is taken into consideration is described as an example, but the present invention is not limited to this. For example, the first B-scan position 51C and the second B-scan position 51D may be adjusted in consideration of the phase of the fiber structure of the sheet material 11 itself. Even when the surface of the sheet material 11 has a non-periodic structure instead of a periodic structure, the first B-scan position 51C and the second B-scan position 51D can be adjusted as described above. Further, the averaging process may be performed by combining the adjustment of the measurement light in the plurality of B-scans described with reference to fig. 4A to 4B and fig. 5A to 5B and the adjustment of the measurement light in the plurality of B-scans described with reference to fig. 6A to 6C. This can provide an effect of removing speckles and suppressing image blurring.

< correction of B-scan image based on height of B-scan position >

Next, the correction of the B-scan image based on the height of the B-scan position will be described with reference to fig. 4A and 4B.

That is, there may be a shift in height in the Z direction between the first B scanning position 51A and the second B scanning position 51B. This is because the shape along the Y direction of the multilayer sheet 10 is not a straight line. If the B-scan images obtained at the first and second B-scan positions 51A, 51B different in height are averaged, the calculation accuracy of the thickness Δ Zs and the thickness Δ Zt performed in step S4 shown in fig. 3 is degraded.

Therefore, averaging is performed after the B-scan image is corrected. This can improve the calculation accuracy of the thickness Δ Zs and the thickness Δ Zt.

Specifically, in the case shown in fig. 4A, the difference H between the height of the first B scanning position 51A and the height of the second B scanning position 51B can be obtained based on the following expression (4). Therefore, the B-scan image at the second B-scan position 51B is shifted in the Z-direction by the amount corresponding to the found difference H.

H＝r×{sinθ1-sin(θ1+Δθ)} (4)

Here, for example, it is assumed that, among images having a height direction (Z direction) of 100 pixels, in the first B-scan image, the multilayer sheet 10 is photographed at the 50 th pixel in height, and in the second B-scan image, the multilayer sheet 10 is photographed at the 55 th pixel in height by being deviated in the Z direction by an amount corresponding to the difference H in height.

In this case, as the offset, the pixels in the Z direction of the second B-scan image are reduced by 5 pixels. This enables the heights of the multilayer sheet 10 in the first B-scan image and the second B-scan image to be matched. As a result, the calculation accuracy of the thickness Δ Zs and the thickness Δ Zt can be improved.

In addition to the above method, the first B-scan image may be given a margin of 5 pixels in the height direction, and the heights of the multilayer sheet 10 in the first B-scan image and the second B-scan image may be made uniform. This can provide the same effects as described above.

< correction of B-scan image based on incident angle of measurement light >

Next, correction of the B-scan image based on the incident angle of the measurement light will be described with reference to fig. 7A. Fig. 7A is a schematic view illustrating a refraction state of the measurement light L in the multilayer sheet 10.

That is, in the case where the incident angle of the measurement light with respect to the multilayer sheet 10 is not perpendicular, and in the case where the refractive index of the multilayer sheet 10 with respect to air is high, the case where refraction occurs in the measurement light L is corrected. Specifically, the refractive indices of the coating material 12 and the sheet material 11 in the multilayer sheet 10 are slightly different, but much smaller than the difference between the refractive indices of air and the resin material.

For the sake of simplicity, the multilayer sheet 10 has the same refractive index n, and will be described below.

For example, as shown in fig. 7A, the measurement light L incident at an angle θ 3 from the vertical direction, which is the thickness direction of the multilayer sheet 10, is incident into the multilayer sheet 10 at an angle θ 4 by refraction in the multilayer sheet 10. The optical path length of the refracted light is D4.

In this case, the angle θ 3 and the angle θ 4 have the relationship of the following expression (5).

sinθ3＝n×sinθ4 (5)

In equation (5), as shown in fig. 7A, the relationship of the angle θ 3 with the position of the inspection roller 51 through the B scan position is known. In addition, the refractive index n is also known. Thus, the angle θ 4 can be obtained by equation (5).

Therefore, the refractive index n and the angle θ 4 are used to multiply the Z-axis of the B-scan image measured by the SS-OCT by the coefficient β shown below. This enables the thickness of the multilayer sheet 10 to be converted into the true thickness T.

That is, the actual thickness T of the multilayer sheet 10 can be obtained based on the following formula (6) with respect to the obtained optical path length D4. At this time, the coefficient β is a value obtained by the following formula (7).

T＝(D4/n)×cosθ4 (6)

β＝1/n×cosθ4 (7)

In the above description, the height of the B-scan position and the correction amount of the B-scan image based on the incident angle of the measurement light are calculated on the assumption that the inspection roller 51 is cylindrical, but the present invention is not limited thereto. The actual measurement values, for example, the pixel values in the depth direction using the front surface position and the back surface position of the multilayer sheet 10 at each B-scan position, may be held in advance as a table. Further, the correction amount may be calculated based on a table held. Thereby, even if the shape of the inspection roller 51 is unknown, the same effect can be obtained.

< method for calculating thickness Z >

Next, a method of calculating the thickness of the multilayer sheet will be described with reference to fig. 7B. Fig. 7B is an explanatory diagram of a method of calculating the thickness of the multilayer sheet 10.

The thickness calculation section 62 of the sheet generation control section 60 measures an interface position Z1, an interface position Z2, and an interface position Z3 shown in the left diagram of fig. 7B based on the obtained B-scan image. In addition, the interface position Z1 is the interface position of air with the coating material 12. The interface position Z2 is the interface position of the coating material 12 and the sheet material 11. The interface position Z3 is an interface position of the sheet material 11 with the back air or with the inspection roller 51.

The measurement of the interface positions Z1, Z2, and Z3 may be performed by using, for example, the peak position of the signal intensity in the Z direction, or may be performed by using another signal processing method such as edge detection for the SS-OCT signal. In this case, filters such as integration may be applied in the X direction and the Y direction, for example, to improve the accuracy of measurement of the interface position.

In embodiment 1 and embodiment 2, the thickness Δ Zs and the thickness Δ Zt may be calculated, and therefore the interface position Z1, the interface position Z2, and the interface position Z3 may be distinguished. Thus, for example, it is not necessary to distinguish which SS-OCT signal corresponding between interface position Z2 and interface position Z3 is the SS-OCT signal from which of sheet material 11 or coating material 12. However, the sheet material 11 and the coating material 12 may be distinguished from each other by the difference in intensity of the scattered light with respect to the measurement light.

Specifically, in the case where the inside of the sheet material 11 is uniform and the inside of the coating material 12 contains the mixture, scattering of the measurement light in the inside of the coating material 12 is large. In this case, as shown in the right diagram of fig. 7B, the signal intensity from the interface position Z1 to the interface position Z2 is stronger than the signal intensity from the interface position Z2 to the interface position Z3. Therefore, it is also possible to distinguish between the sheet material 11 and the coating material 12 by using the difference between the obtained signal intensities.

Further, according to the obtained interface positions Z1, Z2, Z3, (Z2-Z1) becomes an optical thickness including the refractive index of the coating material 12. Further, (Z3-Z2) becomes an optical thickness including the refractive index of the sheet material 11. Therefore, these optical thicknesses are divided by the known refractive indices of the sheet material 11 and the coating material 12. Thereby, each physical thickness Δ Zs and physical thickness Δ Zt are obtained. The physical thickness Δ Zs and the physical thickness Δ Zt herein are average thicknesses in the X direction obtained by 2B scans. For example, the minimum and maximum thicknesses may be defined for each part in the X direction of the B scan. Thus, the minimum value and the maximum value of the thickness within the above range can be adopted as the "physical thickness" without adopting a simple average in the X direction.

The sheet generation control unit 60 drives the applicator 33 while rotating the winding roll 40, and continues the measurement while changing the rotation angle θ of the winding roll 40. Thus, the thickness Δ Zs and the thickness Δ Zt at all rotation angles θ until the end of the production of the multilayer sheet 10 were measured.

From the above, the thickness Δ Zs and the thickness Δ Zt of the multilayer sheet 10 can be calculated.

< determination regarding acceptability of multilayer sheet >

Next, the determination of whether or not the produced multilayer sheet 10 is acceptable will be described.

First, when the multilayer sheet 10 is an adhesive sheet, if the thickness Δ Zt and the thickness Δ Zs are not equal to or larger than a certain value, the multilayer sheet may not function as a multilayer sheet. Specifically, for example, if the thickness Δ Zs of the sheet material 11 is thin, the strength is insufficient. On the other hand, if the thickness Δ Zt of the coating material 12 as an adhesive is thin, the adhesive force may be insufficient.

Therefore, in embodiment 1 and embodiment 2, as the threshold value having a constant size, the first threshold value is used to determine whether or not the multilayer sheet is acceptable. Specifically, the determination unit 63 compares the first threshold value with the thickness Δ Zs and the thickness Δ Zt, and determines whether or not the multilayer sheet is acceptable. At this time, the first threshold is set to 50 μm, for example.

On the other hand, too large values of the thickness Δ Zs and the thickness Δ Zt may cause a problem. Therefore, the thickness Δ Zs and the thickness Δ Zt need to be equal to or smaller than a certain value. Therefore, as the threshold value of a certain size, the second threshold value is used to further determine whether or not the multilayer sheet is acceptable. At this time, the second threshold is set to 100 μm, for example.

That is, the OK range of the multilayer sheet is set to be equal to or higher than the first threshold value and equal to or lower than the second threshold value, and is stored in the storage unit 64 in advance. Then, the determination unit 63 determines whether or not the multilayer sheet 10 is acceptable based on the stored OK range.

< effects of embodiment 1 >

According to embodiment 1, the SS-OCT apparatus 50 using interference light is used to measure the thickness Δ Zs of the sheet material 11 and the thickness Δ Zt of the coating material 12. Therefore, it is not necessary to provide a cover for explosion prevention such as the X-ray thickness meter 93 of patent document 1 on the measurement head 52 constituting the SS-OCT apparatus 50. That is, the installation position of the measuring head 52 can be set in the vicinity of the position where the coating material 12 is applied to the sheet material 11. Thus, the sheet forming apparatus 1 can inspect the thickness of the multilayer sheet 10 that has been formed immediately before, while forming the multilayer sheet 10. Therefore, the tact time from the start of production of the multilayer sheet 10 to the end of inspection of the thickness of the multilayer sheet 10 can be shortened.

(embodiment mode 2)

The sheet forming apparatus 1A according to embodiment 2 of the present disclosure will be described below in sections.

< schematic configuration of sheet Forming apparatus >

First, a schematic configuration of a sheet forming apparatus 1A according to embodiment 2 of the present disclosure will be described with reference to fig. 8.

Fig. 8 is a schematic diagram of a sheet manufacturing apparatus 1A in embodiment 2 of the present disclosure. Note that the same components as those in embodiment 1 are denoted by the same reference numerals and the same names, and description thereof may be omitted.

As shown in fig. 8, the sheet forming apparatus 1A according to embodiment 2 is different from the sheet forming apparatus 1 according to embodiment 1 in that a thickness adjusting unit 70A is further provided, and a sheet generation control unit 60A is provided instead of the sheet generation control unit 60.

The thickness adjusting unit 70A of the sheet forming apparatus 1A includes a pair of rollers 71A that sandwich the multilayer sheet 10, a moving device 72A that changes the thickness of the multilayer sheet 10 by controlling the positions of the pair of rollers 71A, and the like.

The pair of rollers 71A is provided to sandwich the multilayer sheet 10 between the coating roller 31 and the winding roller 40. The moving device 72A is driven to change the gap between the pair of rollers 71A. This structure is configured to change the thickness of the multilayer sheet 10.

The sheet generation control unit 60A is different from the sheet generation control unit 60 according to embodiment 1 in that a feedback control unit 66A is further provided.

Specifically, the feedback control section 66A feeds back the control amount based on the thickness Δ Zs and the thickness Δ Zt obtained using the SS-OCT apparatus 50 to the moving device 72A of the thickness adjustment section 70A. The thickness Δ Zs and the relationship between the thickness Δ Zt and the control amount are stored in the storage unit 64 as a relational expression or a table in advance.

That is, the feedback control unit 66A determines the control amount using a relational expression or a table stored in advance, and feeds back the control amount to the mobile device 72A.

< method for producing sheet >

Next, a sheet forming method performed by the sheet forming apparatus 1A will be described with reference to fig. 9 while referring to fig. 8. Fig. 9 is a flowchart illustrating a sheet manufacturing method. The same steps as those in embodiment 1 are denoted by the same reference numerals, and description thereof may be omitted.

First, as shown in fig. 9, the processing of step S1 to step S9 of embodiment 1 shown in fig. 3 is performed.

Then, in step 9, the operation control section 61 determines whether or not the multilayer sheet 10 is completed. At this time, when the operation control section 61 determines that the multilayer sheet 10 is completed (yes at step S9), the process of step S10 is performed.

On the other hand, when the operation control portion 61 determines that the multilayer sheet 10 is not completed (no in step S9), the feedback control portion 66A calculates the control amount (feedback amount) of the pair of rollers 71A based on the calculation results of the thickness Δ Zs and the thickness Δ Zt in step S4 (step S21).

Then, the feedback control unit 66A performs feedback to the mobile device 72A (step S22).

Next, the moving device 72A adjusts the gap of the pair of rollers 71A based on the feedback amount.

Thereafter, the process returns to step S3, and the SS-OCT measurement by the SS-OCT apparatus 50 is performed again.

Next, as in embodiment 1, the sheet material 11 is cut by a cutting unit (not shown) from the sheet supply reel 20 to the application roller 31 (step S10), and the sheet forming operation of the multilayered sheet 10 is terminated.

(modification example)

The present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present disclosure.

For example, the following configuration can be applied to embodiment 1 and embodiment 2.

Specifically, in the criterion of the determination of whether or not the multilayer sheet 10 is acceptable, the threshold values of the upper limit and the lower limit may be set for the sheet material 11 and the coating material 12, respectively. Thus, for example, when the thickness of the sheet material 11 varies as the material characteristic, the threshold value of the coating material 12 is set strictly in comparison with the upper and lower threshold values of the sheet material 11, thereby obtaining an effect of maintaining the thickness accuracy of the coating material.

In the above description, the actual thickness Δ Zs and the actual thickness Δ Zt are obtained by dividing the optical thickness by the refractive index. For example, the obtained optical thickness may be used as it is as each of the thickness Δ Zs and the thickness Δ Zt, and a threshold value may be set according to the thickness Δ Zs and the thickness Δ Zt. This enables maintaining accuracy even when the refractive index of the object is unknown.

Further, the thickness Δ Zs and the thickness Δ Zt may be calculated based on the result of 1B scan (1B scan image), or the thickness Δ Zs and the thickness Δ Zt may be calculated based on the result of at least 1a scan. Further, the measurement light may be made incident on both surfaces of the multilayer sheet 10, in other words, the sheet material 11 side and the coating material 12 side, and the thickness Δ Zs and the thickness Δ Zt may be measured by the measurement light. At this time, the above-described structure can also be realized by using 2 SS-OCT apparatuses 50. Thus, even when the permeability is insufficient, a good image can be obtained on the back surface side of the sheet material 11.

In the above description, the configuration in which the sheet supply reel 20, the application roller 31, and the inspection roller 51 are not separately provided with the drive sources for rotating the respective components has been described as an example, but the rotation drive devices such as motors may be separately provided. This makes it easier to control the traveling speed than when the vehicle is driven by a single motor.

In embodiment 2, a structure in which a mechanism for adjusting the gap between the pair of rollers 71A is adopted as the thickness adjusting portion 70A has been described as an example, but the invention is not limited thereto. Other mechanisms having a function of adjusting and regulating the thickness of the multilayer sheet 10 in the Z-axis direction, for example, a mechanism of adjusting the thickness of the multilayer sheet 10 by heating, may be used. Further, for example, a mechanism may be employed in which only the thickness of the coating material 12 is adjusted by a peeling action such as a doctor blade. Thereby, an effect of enabling thickness adjustment can be obtained regardless of the physical properties of the coating material.

In embodiment 2, the thickness adjustment portion 70A has been described by taking as an example a configuration in which the thickness of the multilayer sheet 10 is changed by sandwiching the multilayer sheet 10, but the present invention is not limited thereto. For example, the thickness of the sheet material 11 may be changed by holding only the sheet material 11 therebetween. Further, only the coating thickness by the coater 33 may be changed. In this case, the thickness of both the sheet material 11 and the coating material 12 may be changed at the same time.

In addition, any of the above-described embodiments and modifications may be appropriately combined. This can achieve the respective effects.

In embodiment 1 and embodiment 2, speckles occur when infrared light as measurement light passes through the resin, and the accuracy of the detected thickness is lowered. Thus, as described above, it is more desirable to measure the thicknesses of the sheet material 11 and the coating material 12 in the inspection roller 51 in the process of manufacturing the multilayer sheet, but not limited thereto. For example, the thickness can also be determined using SS-OCT measurements after the completion of the multiwall sheet 10. This enables measurement to be performed in a stable environment as compared with the inspection roller 51.