JP2017020907A - Measurement device and measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To observe or non-destructively measures a process of infiltration of a material, such as a liquid applied to a sheet-like medium, such as a film and sheet, to the medium at various speeds of infiltration and high time resolution.SOLUTION: An optical interference tomographic measurement device 1 comprises: a light source 6; an observation optical system 2; a reference optical system 3; and a processing control part 20. Light from the light source 6 is divided into measurement light and reference light by a fiber coupler 7. The measurement light is used to irradiate a sheet-like measurement object 12 that is applied with an application material by a liquid application device 18 while being conveyed by a conveyance device 11. The processing control part 20 forms a tomographic image on the basis of interference light between light integrated by the fiber coupler 7 and returning from the measurement object 12 and light returning from the reference optical system 3. A processing part 22 determines a chronological change in the position of an infiltration boundary on the basis of a conveyance speed and the position of the infiltration boundary on the tomographic image.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a measuring apparatus and a measuring method for measuring a penetration process of a coating material into a medium being conveyed in a nondestructive manner.

  2. Description of the Related Art There are printers and printing machines that form a functional member such as a document, an image, or an electronic circuit by applying droplets such as ink on a sheet-like medium such as a film or coated paper. In such an apparatus, in order to optimize the image quality to be formed, the amount of applied droplets, and improve the reliability of the functional member, the state of penetration of the droplets in the thickness direction of the medium may be evaluated. An optical coherence tomography method is known as a method for evaluating the penetration state of a droplet.

  Patent Document 1 discloses a technique for obtaining a tomographic image of a state where a liquid permeates from the back surface of a medium using an optical coherence tomography method, and analyzing the obtained tomographic interface position, that is, a technique for quantifying a permeation speed. Is described. That is, the permeation process measuring device described in Patent Document 1 is provided in a light source unit, a light dividing unit that divides light from the light source unit into an optical path of reference light and an optical path of measurement light, and an optical path of the reference light. A reference optical system, a measurement optical system that is provided in the optical path of the measurement light and measures the measurement target medium, and a light combining unit that combines the reflected / scattered light of the measurement light by the measurement target medium and the reference light from the reference optical system A detection unit that detects the combined light combined by the light combining unit and outputs a photoelectric conversion signal, an image construction unit that images a cross-section of the measurement target medium using the photoelectric conversion signal, and an image construction unit A display unit that displays the cross-sectional image and an application unit that applies the permeable substance to the measurement target medium, and measures the penetration state while applying the permeable substance to the back surface of the measurement target medium.

  However, in the technique described in Patent Document 1, it is not easy to measure the permeation behavior that occurs in a time shorter than the time resolution. In optical coherence tomography, in order to grasp the behavior in a short time, generally use a photodetector that can detect the interferometric light at high speed, or replace the mechanical scanning of the measuring light with optical scanning. However, there is a problem that the measurable time is shortened, the measurement sensitivity is lowered, and the cost of the apparatus member is increased.

  The present invention has been made in view of the above problems, and its purpose is to measure the penetration state of a coating material penetrating into a medium at various speeds without destroying the medium with an arbitrary time resolution. An object of the present invention is to provide a measuring device that can be used.

  In order to solve the above problem, the invention according to claim 1 is directed to a light source unit, a light dividing unit that divides light from the light source unit into measurement light and reference light, and irradiating the reference mirror with the reference light. A reference optical system for acquiring return light from a reference mirror, an observation optical system for irradiating the measurement object with the measurement light and acquiring return light by reflected light or scattered light from the measurement object, and the reference mirror An optical coupling unit that couples the return light from the measurement object and the return light from the measurement object, a light detection unit that detects an interference signal of the light coupled by the optical coupling unit, and a detection result of the light detection unit A measurement device that measures the internal state of the measurement object by optical coherence tomography, and measures the internal state of the measurement object based on the interference signal. In the direction intersecting the irradiation direction of the measurement light Conveying means for, characterized in that it comprises a coating means for applying a coating material to the measurement object during transport.

  ADVANTAGE OF THE INVENTION According to this invention, the penetration | infiltration state of the coating material which osmose | permeates a medium at various speeds can be measured with arbitrary time resolution, without destroying a medium.

It is the schematic which shows the optical system and control system of the optical coherence tomography measuring apparatus which concern on embodiment of this invention. It is the schematic which shows the positional relationship of the observation optical system periphery of the optical coherence tomography measuring apparatus. It is the schematic which shows the difference of the acquired tomographic image with respect to the measurement object medium conveyance speed acquired with the same optical coherence tomography measuring apparatus. It is the schematic which shows the time calendar of the permeable interface position judged in each conveyance speed setting acquired with the same optical coherence tomography measuring apparatus.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
The present invention has the following configuration in order to measure the penetration state of a coating material that penetrates a medium at various speeds without destroying the medium with an arbitrary time resolution.
That is, the measurement apparatus of the present invention is a measurement apparatus for measuring the internal state of a measurement object using an optical coherence tomography method, and includes a light source unit that generates light and light from the light source as reference light. A dividing unit that divides the light into measurement light, a detection unit that detects a combined light of reflected light or scattered light from the measurement object and the reference light, and a process that displays after processing the signal detected by the detection unit A measuring device comprising: an application unit that applies a material to the measurement object; and a conveying unit that conveys the measurement object, and the material is measured by the measurement device. The internal state of the measurement object being conveyed is measured by the conveying means while being continuously applied to the object.
By providing the above configuration, it is possible to measure the penetration state of the coating material penetrating into the medium at various speeds without destroying the medium with an arbitrary time resolution.

First, the technical background and outline of the present invention will be described.
When a liquid is applied as an application to one side of a measurement object that is a sheet-like medium that absorbs the liquid, the liquid penetrates from the application surface in the depth direction of the measurement object with time. At this time, the time required until the liquid permeation is completed, that is, until the liquid permeation interface reaches the side opposite to the liquid application surface or the movement of the liquid permeation interface is completed, Depending on the combination, it can vary from milliseconds to several hours.
In optical coherence tomography, the reflected or scattered light of the light irradiated on the surface or inside of the measurement object is detected using light interference, and the detected interference signal is converted into an electrical signal. Is converted into a luminance value based on the signal intensity. Thereby, the internal structure and internal state of the measurement object can be known as a tomographic image.

  When a tomographic image is acquired in a state where the liquid has permeated a part of the measurement object, the image intensity of the region in which the liquid has permeated is changed as compared with the tomographic image acquired in a state where the liquid is not permeated. The penetration of the liquid into the measurement object proceeds as the minute voids inside the measurement object are gradually filled with the liquid. When light is applied to the interface of the air gap inside the measurement object, there is a difference in refractive index between the air and the measurement object, so the light is divided at a certain ratio between reflected light and transmitted light based on the Fresnel relational expression. Is done.

  However, when light is applied to the interface of a gap that is infiltrated and filled with liquid, the difference in refractive index between the liquid and the measurement object is generally different compared to the difference in refractive index between air and the measurement object. The ratio at which light is divided into reflected light and transmitted light also changes. Therefore, in order to know the region where the liquid penetration has progressed based on the tomographic image, the tomographic image in a state where the liquid has penetrated (when the liquid is applied) and a state where the liquid has not penetrated (when the liquid is not applied) It is only necessary to generate a differential tomographic image compared with the tomographic image in FIG.

  In the present invention, liquid is continuously applied to a sheet-like medium that is conveyed at a constant speed, and an imaging surface that is a surface that does not include an axis orthogonal to the conveyance direction on the liquid application surface of the measurement object is acquired as a tomographic image. To do. As a result, one of the axes (representing the distance) including the transport direction component on the differential tomographic image is divided by the axial direction component of the medium transport speed to convert to the time axis. In addition, by projecting the axis (representing the distance) perpendicular to the conveyance direction axis on the differential tomographic image to the thickness (depth) direction axis of the measurement object, the penetration depth of the liquid with respect to the elapsed time after liquid application Changes, i.e. permeation rate characteristics, can be measured.

  Further, according to the present invention, it is possible to control the time region in which the penetration rate characteristic can be measured by adjusting the conveyance speed of the measurement object or adjusting the positional relationship of the imaging surface with respect to the measurement object. For this reason, even in a combination of a liquid and a measurement object having different penetration speeds, the penetration speed characteristics can be measured with high temporal resolution without changing the tomographic image acquisition speed of the optical coherence tomography measurement.

<Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. . FIG. 1 is a schematic diagram showing an optical system and a control system of an optical coherence tomography measuring apparatus according to an embodiment of the present invention. An optical coherence tomography measuring apparatus 1 which is a measuring apparatus according to an embodiment of the present invention includes an observation optical system 2, a reference optical system 3, an interferometer unit 4, a transport apparatus 11, a liquid coating apparatus 18, and a process control. Part 20.

The interferometer unit 4 includes a light source 6 that is a light source unit, a fiber coupler 7 that serves as a light splitting unit and an optical coupling unit, and a light detection unit 14. The light source 6 generates broadband light whose center wavelength belongs to the near infrared wavelength region. For example, the light generated by the light source 6 is broadband light having a center wavelength in the near-infrared wavelength region of 0.7 μm to 2.0 μm and a coherence distance of 20 μm or less.
The fiber coupler 7 functions as an optical dividing unit and an optical coupling unit. The fiber coupler 7 includes a light guide fiber 7a, a measurement optical fiber 7b, a reference optical fiber 7c, a measurement fiber 7d, and an optical division coupling unit 7e. The light from the light source 6 enters the light guide fiber 7a, is divided into measurement light and reference light by the light splitting and coupling unit 7e, and the measurement light is emitted from the measurement optical fiber 7b and the reference light is emitted from the reference optical fiber 7c. Is done. Light from the measurement optical fiber 7 b is incident on the observation optical system 2, and light from the reference optical fiber 7 c is incident on the reference optical system 3.
The return light from the observation optical system 2 reaches the light splitting / coupling unit 7e via the measurement optical fiber 7b, and the return light from the reference optical system 3 reaches the light splitting / coupling unit 7e via the reference optical fiber 7c. These lights are coupled by the light splitting and coupling unit 7e and emitted from the measurement fiber 7d. The emitted light is incident on the light detection unit 14, and the light detection unit 14 detects the interference state of the combined light from the measurement fiber 7d. The light detection unit 14 includes a photoelectric conversion element.

The observation optical system 2 includes a lens L2, a galvano scanner 8, and a scanning lens 10. The measurement light from the measurement optical fiber 7b is scanned by the galvano scanner 8 through the lens L2. The galvano scanner 8 includes two galvanometer mirrors 8a and 8b. The galvanometer mirrors 8 a and 8 b are driven and controlled by the control unit 21.
In this example, the galvanometer mirrors 8a and 8b are both driven to reciprocate. By driving the galvanometer mirrors 8a and 8b as described above, two-dimensional and three-dimensional cross-sectional image data can be acquired.

  The lens L2 converts the light emitted from the measurement optical fiber 7b into a parallel light beam. The parallel light beam enters the scanning lens 10 as measurement light. The scanning lens 10 has a role of always making the parallel light beam from the galvano scanner 8 incident on the measurement object 12 from the vertical direction to form spot light. Thus, a cross-sectional image can be accurately acquired by forming an image by allowing a parallel light beam to enter the measurement object 12 from the vertical direction. The return light from the measurement object 12 enters the measurement optical fiber 7b from the lens L2 via the scanning lens 10 and the galvano scanner 8.

  The reference optical system 3 includes a lens L3, a lens L4, and a reference mirror 13. The reference light from the reference optical fiber 7c is irradiated to the reference mirror 13 through the lenses L3 and L4, is totally reflected by the reference mirror 13, and returns to the reference optical fiber 7c through the lenses L4 and L3.

  The conveyance device 11 conveys the measurement object 12 in a predetermined conveyance direction that intersects the irradiation direction of the measurement light emitted to the measurement object 12. The measurement object 12 is a film-like or plate-like object or a print medium. When measuring the internal state of the measurement object 12, the liquid application device 18 applies the liquid to the surface opposite to the scanning lens 10 that is the measurement light irradiation side with the measurement object 12 interposed therebetween.

The processing control unit 20 includes a control unit 21, a processing unit 22, a storage unit 23, and a display unit 24 that are control means. The control unit 21 is configured as a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. In the control unit 21, the CPU reads out a predetermined program stored in the ROM or the storage unit 23, develops it in the RAM, and executes it, thereby realizing the functions of the respective units.
The processing unit 22 processes the signal acquired by the light detection unit 14 with a program based on the optical coherence tomography. The storage unit 23 stores signal data and tomographic images acquired by measurement. The display unit 24 displays signal data and tomographic images acquired by measurement.

In the optical coherence tomography measuring apparatus 1, the light output from the light source 6 is guided to the end of the light guide fiber 7a of the fiber coupler 7 through the lens L1. This light is split in the light splitting and coupling unit 7e and travels to the observation optical system 2 through the measurement optical fiber 7b and to the reference optical system 3 through the reference optical fiber 7c. The light traveling toward the observation optical system 2 is converted into a parallel beam through the lens L <b> 2, and then irradiated onto the measurement object 12 by the galvano scanner 8 and scanned along the surface of the measurement object 12.
Here, the operation of the galvano scanner 8 will be described. In FIG. 1, it is assumed that the left-right direction (the direction along the conveyance direction of the measurement object 12) is the x-axis direction, the direction perpendicular to the paper surface of FIG. 1 is the y-axis direction, and the vertical direction in FIG. The galvano scanner 8 includes two galvanometer mirrors 8a and 8b. One galvanometer mirror 8a reciprocally swings about the z axis (around the z axis), and scans the measurement light in a direction intersecting the transport direction in the xy plane. The other galvanometer mirror 8b reciprocally swings around the y axis (around the y axis), and scans the measurement light in the transport direction within the xy plane. By this operation, the galvano scanner 8 can acquire three-dimensional cross-sectional image data obtained by scanning the measurement object 12 with measurement light at least in the transport direction. Note that the swing directions of the two galvanometer mirrors may be interchanged.
In the optical coherence tomography measuring apparatus 1, at least one galvanometer mirror, for example, the galvanometer mirror 8b, is swung around the y-axis to scan the measurement light in the transport direction of the measurement object 12, thereby obtaining two-dimensional or more cross-sectional image data. To get. The scanning direction of the measurement light may be a direction that is not orthogonal to the transport direction at least in the plane of the measurement object 12 (in the xy plane). That is, when the direction orthogonal to the transport direction (y-axis direction) is the first direction, the measurement light may be scanned in the second direction that intersects the first direction. Thereby, cross-sectional image data including at least a conveyance direction component can be obtained.
The galvano scanner 8 is driven and controlled by the control unit 21. The measurement object 12 is conveyed in a certain direction (right direction in FIG. 1) by the conveying device 11. Part of the light irradiated to the measurement object 12 returns to the fiber coupler 7 through the observation optical system 2 due to reflection and scattering on the surface and inside of the measurement object 12. On the other hand, the light traveling toward the reference optical system 3 is irradiated and reflected on the reference mirror 13 through the lens L3 and the lens L4, and returns to the fiber coupler 7 through the reference optical system 3.

  The return light from each of the observation optical system 2 and the reference optical system 3 interferes in the optical division coupling unit 7e of the fiber coupler 7, and is input to the light detection unit 14 through the lens L5 and the lens L6. The interference signal detected by the light detection unit 14 is converted into an electric signal, taken into the processing control unit 20, and then formed into a tomographic image by signal processing of the processing unit 22. The data is stored in the storage unit 23 and displayed. It is displayed on the part 24 as appropriate.

  With such a configuration, the optical coherence tomography measuring apparatus 1 drives the galvano scanner 8, the transport apparatus 11 as the transport means, and the liquid coating apparatus 18 as the coating means by the control unit 21 to apply the liquid to the measurement target 12. It is possible to measure the state in which the liquid has permeated the measurement object 12 or the process of permeation while being applied from the apparatus 18. Note that the transport device 11 can freely change the transport speed of the measurement object 12. The control of the conveyance speed is executed by the control unit 21.

FIG. 2 is a schematic diagram showing the positional relationship around the observation optical system of the optical coherence tomography measuring apparatus according to the present embodiment. This figure shows a state in which a part of the observation optical system 2 is viewed from a direction orthogonal to the optical axis of the measurement light.
The measurement light is applied to the measurement object 12 through the scanning lens 10. The measurement object 12 is transported in one direction by the transport device 11 at a speed v. For this reason, the liquid permeates while being conveyed through the measurement object 12. Since the velocity v is kept constant during the acquisition of the tomographic image, the tomographic image having the shape of the permeation region 32 that looks similar to the tomographic image is obtained with time regardless of the acquisition timing of the tomographic image and the number of acquired tomographic images per unit time. You can get it. In FIG. 2, the droplets 30 ejected from the liquid coating device 18 are applied as a coating material 31 to the measurement object 12 transported by the transport device 11. Then, the coating 31 penetrates into the base 33 of the measurement object 12, and a permeation region 32 is formed in the base 33.
Here, the liquid application device 18 applies the liquid linearly along the direction intersecting the transport direction to the measurement object 12 so that the liquid spreads in a planar shape on the application surface of the measurement object 12. To. This facilitates adjustment of the scanning position by the galvano scanner 8.

  FIG. 3 is a schematic diagram illustrating a difference in acquired tomographic images with respect to a measurement target medium conveyance speed acquired by the optical coherence tomography measuring apparatus according to the present embodiment. Time elapses in the order of FIGS. 3A, 3B, and 3C. In each figure, an image of the applied application itself (an image of the application that does not penetrate the measurement object) is omitted. It can be seen that the permeation region 32 expands to the deep portion of the base body 33 of the measurement target 12 as the conveyance proceeds with respect to the liquid application position. In the differential tomographic image, a differential component derived from the non-uniformity of the measurement object may appear as image noise. In order to reduce this influence, it is possible to newly treat a differential tomographic image obtained by averaging differential tomographic images acquired at different times under the same transport conditions and application conditions as a differential tomographic image.

  Here, when the conveyance speed of the measurement object 12 is changed to v0, v1, and v2 (provided that v0> v1> v2), the shape of the permeation interface position changes. The distance from the liquid application position on the tomographic image is the product of the elapsed time after liquid application and the conveyance speed. Therefore, if the conveyance speed v is constant and known, the shape of the penetration interface position can be converted into a graph representing the relationship of the penetration depth of the liquid with respect to the elapsed time after the liquid application.

When measuring the permeation speed of the liquid that permeates the measurement object 12 at a certain speed, for example, it is assumed that a tomographic image as shown in FIG. 3B is acquired at the conveyance speed v1 of the measurement object 12. When it is desired to grasp the permeation behavior for a longer time after the application of the liquid, the tomographic image as shown in FIG. 3C is acquired by reducing the conveyance speed of the measurement object 12 to v2. (Elapsed time after liquid application) = (distance from liquid application position on tomographic image) / (conveying speed) By reducing the speed, it is possible to take longer time for evaluating the penetration depth. it can.
On the other hand, when it is desired to grasp the permeation behavior in a shorter time after applying the liquid, the tomographic image as shown in FIG. (Elapsed time after liquid application) = (Distance from liquid application position on tomographic image) / (Conveyance speed) By increasing the conveyance speed, the time during which the penetration depth can be evaluated is shortened. Can do.
That is, because the tomographic image width and pixel pitch are fixed, or by making the tomographic image width and pixel pitch known for each measurement, it is faster to measure penetration behavior in a shorter time. Thus, in order to measure the permeation behavior for a longer time, the time resolution of the permeation rate determination can be freely changed by conveying the measurement object 12 at a lower speed.

  Graphs representing the relationship of the penetration depth of the liquid with respect to the elapsed time after the liquid application obtained based on the tomographic images acquired at different conveyance speed settings can be superimposed. FIG. 4 is a schematic diagram showing the time calendar of the permeation interface position determined in each conveyance speed setting acquired by the optical coherence tomography measurement apparatus. In FIG. 4, the graph A is quantified based on the tomographic image acquired at the transport speed v0, the graph B is at the transport speed v1, and the graph C is at the transport speed v2 (v0> v1> v2). For example, when acquiring penetration depth data for each fixed pixel pitch on the tomographic images of FIGS. 3A to 3C, the number of data per unit time increases as the conveyance speed increases. It can be seen that the time range in which data can be acquired is narrow. In FIG. 4, the permeation rate of the liquid appears as the slope of the graph.

  When it is desired to know in detail the penetration characteristics after an arbitrary time has elapsed since the liquid application, not immediately after the liquid application, the position of the tomographic image acquired from the measurement object 12 is set in the transport direction of the measurement object 12 (separated from the liquid application position). (In the direction to do). That is, the tomographic image may be acquired by irradiating the measurement light to a predetermined range including a point where an arbitrary time has elapsed from the application of the liquid in the measurement object 12. In order to acquire such a tomographic image, the optical coherence tomography measurement apparatus 1 according to the present embodiment drives a motor or the like that moves the liquid application apparatus 18 or the observation optical system 2 forward and backward along the conveyance direction of the measurement object 12. The control unit 21 can be configured to drive and control the drive means. When the acquisition position of the tomographic image is changed, for example, data such as graph D can be acquired.

  In any case, the penetration speed of the liquid is measured by measuring the distance in the transport direction from the reference position (eg, liquid application position or penetration measurement start position) in the time axis direction on the tomographic image to a specific position (eg, penetration measurement end position). Conversion to a time axis based on the conveyance speed of the object 12 and calculation based on the penetration depth at the reference position and the specific position can be made.

In the optical coherence tomography measuring apparatus 1, a two-dimensional tomographic image is acquired when only one of the two galvanometer mirrors 8a and 8b of the galvano scanner 8 is driven, and a two-dimensional or three-dimensional tomographic image is acquired when both scanners are driven. it can.
When acquiring a two-dimensional cross-sectional image, the galvano scanner 8 scans in a direction in which a temporal change in permeation behavior is recorded on any axis of a tomographic image from which measurement light is acquired. That is, one galvanometer mirror of the galvano scanner 8 is appropriately driven to scan in a direction including at least the conveyance direction component of the measurement object 12, that is, a direction not perpendicular to the conveyance direction. In other words, when the direction perpendicular to the conveyance direction of the measurement object 12 (the direction perpendicular to the paper surface in FIG. 3) is defined as the first direction in the application surface of the application object with respect to the measurement object 12, the galvano scanner 8 Scans the measurement object 12 in a second direction intersecting the first direction. Then, the processing unit 22 acquires a tomographic image in which the horizontal axis represents the direction scanned by the galvano scanner 8 and the vertical axis represents the thickness direction. In this case, the tomographic image can be acquired so as to form an angle with respect to the transport direction. This is done when it is desired to improve the time resolution of the penetration rate measurement.
On the other hand, when acquiring a three-dimensional cross-sectional image, the measurement light is scanned in an arbitrary direction. It is possible to obtain a two-dimensional tomographic image corresponding to a tomographic image obtained by scanning the measurement object 12 along the transport direction from the acquired three-dimensional tomographic image. In this case, for example, the direction along the conveyance direction of the measurement object 12 is the horizontal axis, the direction along the thickness direction of the measurement object 12 is the vertical axis, and a three-dimensional tomographic image is formed on a plane defined by both axes. Let the image obtained by projecting be a two-dimensional tomographic image. The two-dimensional tomographic image obtained in this way can be handled as a tomographic image obtained by scanning the measurement light in the conveyance direction of the measurement object.

  In the present embodiment, the case where one axis of the two-dimensional tomographic image is the conveyance direction of the measurement object 12 and the other axis is the medium thickness direction has been described, but one axis of the two-dimensional tomographic image is the measurement object. A direction that forms an angle with the transport direction of 12 (provided that this direction is a direction that is not orthogonal to the transport direction), and a direction that forms an angle with the thickness direction of the object to be measured (however, this direction) In this case, the permeation characteristics can be quantified by correction based on the geometric relationship of tomographic images if the respective angles are known. . In the three-dimensional tomographic image, for example, the permeation characteristics of the measurement target 12 can be quantified as a direction distribution perpendicular to the transport direction within the plane of the measurement target by the same procedure as the two-dimensional tomographic image.

  As described above, the optical coherence tomography measurement apparatus according to the present embodiment includes the observation optical system, the reference optical system, the interferometer unit, and the processing control unit, and is further irradiated with the measurement light from the observation optical system. A transport unit configured to transport a measurement object; and a liquid application device installed so as to apply a liquid to a surface opposite to the measurement light irradiation side of the measurement object being transported by the transport unit. . Thereby, the process of infiltrating after applying the liquid to the measurement object being transported can be recorded as a tomographic image without being affected by the optical effect of the liquid by measurement from the side opposite to the application surface. Since the transport means for transporting the measurement object can control the transport speed, the time information recorded in the tomographic image can be changed.

In addition, the storage unit records a tomographic image of the process of liquid permeating into the measurement object and the corresponding conveyance speed information, and the processing unit reads these and performs comparison processing with the tomographic image at the time of non-penetration. And the time calendar of the liquid permeation interface position is determined based on the processing result. That is, the liquid permeation rate can be calculated with free time resolution.
In the above-described embodiment, the optical coherence tomography measuring apparatus 1 is described as being used alone and measuring the penetration state of a liquid into the medium. However, the optical coherence tomography measuring apparatus 1 is incorporated in an ink jet printer, Measurement can be performed while printing. In addition, it is also possible to incorporate a liquid medicine or a coating material into a device or system for coating a sheet material.

<Configuration, operation and effect of exemplary embodiment of the present invention>
<First aspect>
In this embodiment, the return light from the reference mirror 13 by irradiating the reference mirror 13 by irradiating the reference light with the light source 6, the fiber coupler 7 that is a light splitting unit that splits the light from the light source 6 into measurement light and reference light. The reference optical system 3 for acquiring the measurement light, the observation optical system 2 for irradiating the measurement object 12 with the measurement light and acquiring the return light by the reflected light or the scattered light by the measurement object, the return light from the reference mirror 13 and the above-mentioned A fiber coupler 7 that is an optical coupling unit that couples return light from the measurement object, a light detection unit 14 that detects an interference signal of light coupled by the fiber coupler 7, and a detection result of the light detection unit 14 is processed. And a processing unit 22 that measures the internal state of the measurement object by optical coherence tomography, and measures the internal state of the measurement object 12 based on the interference signal. Intersects the direction of measurement light irradiation A conveying device 11 for conveying the that direction, and the liquid coating apparatus 18 for applying a coating material to the measurement object 12 being conveyed, characterized in that it comprises a.
According to this aspect, optical tomography measurement is performed while applying the coating material from the liquid coating device 18 to the measurement object 12 being transported by the transport device 11. Thereby, the penetration state of the coating material penetrating the measurement object 12 at various speeds can be measured with an arbitrary time resolution without destroying the measurement object 12.

<Second aspect>
In this aspect, the measurement object 12 is a film-like or plate-like object or a print medium, and the application object applied by the application means is a liquid.
According to this aspect, it is possible to measure the state of penetration of liquid into a film or plate-like object or a printing medium in a printer or a printing press.

<Third aspect>
In this embodiment, the liquid application device 18 is provided on the side opposite to the measurement light irradiation side with the measurement object 12 interposed therebetween.
According to this aspect, the application is applied to the measurement object 12 from the opposite side of the measurement light. Thereby, it is possible to perform measurement without receiving the optical influence of the liquid.

<4th aspect>
In this embodiment, the liquid application device 18 is characterized in that the application material is applied linearly along a direction intersecting the transport direction.
For example, when obtaining a two-dimensional tomographic image, the measurement light is scanned along the conveyance direction. However, when the spread of the coating material in the direction intersecting the conveyance direction is small, it is necessary to strictly adjust the scanning position of the measurement light. is there. In this aspect, the application is applied linearly in the direction intersecting the conveyance direction with respect to the measurement object. Since the measurement object is conveyed in the conveyance direction, the application object spreads in a planar shape on the application surface of the measurement object. As a result, it becomes easy to adjust the irradiation position of the measurement light, and it becomes easy to measure the state where the coating material penetrates as a tomographic image.

<5th aspect>
In this aspect, when the direction orthogonal to the transport direction in the liquid application surface of the measurement object 12 is the first direction, the processing unit 22 is configured to measure the measurement object 12 in the second direction that intersects the first direction. A tomographic image is generated.
Since the second direction is a direction that is not orthogonal to the transport direction, a temporal change due to transport of the measurement object 12 is recorded in the tomographic image. Therefore, according to this aspect, the penetration state of the coated material can be measured in detail.

<Sixth aspect>
In this aspect, the processing unit 22 generates a differential tomographic image that is a difference between a tomographic image when the coating material is applied and a tomographic image when the coating material is not applied.
The processing unit 22 has a tomographic image in a state in which the coating material has penetrated the measurement object and a state in which the coating material has not penetrated the measurement object in order to know a region where the coating material has penetrated on the tomographic image. A differential tomographic image is generated by comparing with a tomographic image at. In the differential tomographic image, a portion where a difference of a certain value or more is generated in the luminance value is a region where the penetration of the coating material has progressed. The processing unit 22 can measure the penetration state of the coating in detail by generating a differential tomographic image.

<Seventh aspect>
In this aspect, the processing unit 22 is configured such that the conveyance speed of the measurement object 12, the distance in the conveyance direction from the application position to the specific position, which is the reference position obtained from the tomographic image, and the penetration depth of the application object at the reference position. Then, based on the penetration depth of the coating material at the specific position, the penetration speed of the coating material is calculated.
In this aspect, the conveyance direction distance from the reference position to the specific position is converted into a time axis according to the conveyance speed of the measurement object 12. Therefore, if the penetration depths of the coating material at the reference position and the specific position are known, the penetration speed of the coating material can be calculated.

<Eighth aspect>
In this aspect, the transport device 11 is characterized in that the transport speed of the measurement object 12 can be changed.
According to this aspect, it is possible to perform measurement while conveying the measurement object 12 at various speeds. Thereby, the osmosis | permeation rate of a coating material can be measured with arbitrary time resolution.

<Ninth aspect>
This aspect is characterized in that the light output from the light source 6 is broadband light whose central wavelength belongs to the near-infrared wavelength region.
According to this aspect, the light source 6 outputs the broadband light belonging to the wavelength range of the near-infrared wavelength of the measurement object 12. Thereby, it is possible to perform observation up to a deep region of the measurement object 12.

<10th aspect>
In this embodiment, the light source 6, the fiber coupler 7 that is a light splitting unit that splits the light from the light source unit into measurement light and reference light, and the reference mirror 13 are irradiated with the reference light to return from the reference mirror 13. Reference optical system 3 that acquires light, observation optical system 2 that irradiates the measurement object 12 with measurement light and acquires return light by reflected light or scattered light from the measurement object 12, and return light from the reference mirror 13 And a fiber coupler 7 that is an optical coupling unit that couples the return light from the measurement object 12, a light detection unit 14 that detects an interference signal of light coupled by the optical coupling unit, and a detection result of the light detection unit A measurement unit that measures the internal state of the measurement object by an optical coherence tomography method, the measurement being carried in a direction that intersects with the measurement light irradiation direction. While applying the coating to the object, And performing measurement of the internal state of the measurement object based on the interference signal.
According to this aspect, optical tomography measurement is performed while applying the coating material from the liquid coating device 18 to the measurement object 12 being transported by the transport device 11. Thereby, the penetration state of the coating material penetrating the measurement object 12 at various speeds can be measured with an arbitrary time resolution without destroying the measurement object 12.

  DESCRIPTION OF SYMBOLS 1 ... Optical coherence tomography measuring device, 2 ... Observation optical system, 3 ... Reference optical system, 4 ... Interferometer part, 6 ... Light source, 7 ... Fiber coupler, 8 ... Galvano scanner, 11 ... Conveyance apparatus (conveyance means), 12 ... Measurement object, 14 ... light detection unit, 18 ... liquid coating device (application unit), 20 ... processing control unit, 21 ... control unit, 22 ... processing unit

JP2015-004632A

Claims (10)

A light source unit;
A light splitting unit for splitting light from the light source unit into measurement light and reference light;
A reference optical system for irradiating a reference mirror with the reference light to obtain return light from the reference mirror;
An observation optical system that irradiates the measurement object with the measurement light and obtains return light by reflected light or scattered light from the measurement object;
An optical coupling unit that couples the return light from the reference mirror and the return light from the measurement object;
A light detection unit for detecting an interference signal of light coupled by the light coupling unit;
A processing unit for processing a detection result of the light detection unit;
A measuring device for measuring the internal state of the measurement object by optical coherence tomography,
Transport means for transporting the measurement object in a direction intersecting the irradiation direction of the measurement light when measuring the internal state of the measurement object based on the interference signal;
An application means for applying an application to the measurement object being conveyed;
A measuring device comprising:   The measurement apparatus according to claim 1, wherein the measurement object is a film-like or plate-like object or a print medium, and the application object applied by the application unit is a liquid.   The measurement apparatus according to claim 1, wherein the application unit is provided on a side opposite to the measurement light irradiation side with the measurement object interposed therebetween.   The measuring apparatus according to claim 1, wherein the application unit applies the application material linearly along a direction intersecting the transport direction.   When the first direction is a direction orthogonal to the transport direction in the application surface of the application object with respect to the measurement object, the processing unit is configured to measure the measurement object in a second direction that intersects the first direction. The measurement apparatus according to claim 1, wherein a tomographic image is generated.   6. The measurement according to claim 5, wherein the processing unit generates a differential tomographic image that is a difference between the tomographic image at the time of applying the coating material and the tomographic image at the time of non-coating of the coating material. apparatus.   The processing unit includes a conveyance speed of the measurement object, a conveyance direction distance from a reference position obtained from the tomographic image to a specific position, a penetration depth of the application object at the reference position, and the application at the specific position. The measuring apparatus according to claim 5, wherein a penetration speed of the coated material is calculated based on a penetration depth of the material.   The measurement apparatus according to claim 1, wherein the conveyance unit is capable of changing a conveyance speed of the measurement object.   9. The measuring apparatus according to claim 1, wherein the light output from the light source unit is broadband light whose central wavelength belongs to a near-infrared wavelength region. A light source unit;
A light splitting unit for splitting light from the light source unit into measurement light and reference light;
A reference optical system for irradiating a reference mirror with the reference light to obtain return light from the reference mirror;
An observation optical system that irradiates the measurement object with the measurement light and obtains return light by reflected light or scattered light from the measurement object;
An optical coupling unit that couples the return light from the reference mirror and the return light from the measurement object;
A light detection unit for detecting an interference signal of light coupled by the light coupling unit;
A processing unit for processing a detection result of the light detection unit;
A measuring method in a measuring apparatus for measuring the internal state of the measurement object by optical coherence tomography,
A measurement method comprising: measuring an internal state of the measurement object based on the interference signal while applying an application to the measurement object being transported in a direction crossing the irradiation direction of the measurement light. .

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