JP7141120B2 - Thickness measuring device - Google Patents

Description

The present invention relates to a thickness measuring device. More specifically, the present invention relates to a thickness measuring device that measures the thickness of an object to be measured using spectral interference.

2. Description of the Related Art Conventionally, a measurement method using spectral interference is known as one of techniques for measuring the thickness of a transparent, homogeneous and flat object to be measured such as films and coatings. In this measurement, the spectral reflectance of the object to be measured is measured by utilizing the fact that the interference phenomenon of the reflected light from the front surface and the back surface of the object to be measured has a correlation with the film thickness, and this spectral reflectance is analyzed. A film thickness is calculated (Patent Document 1).

In addition, in order to deal with the increase in the size of the object to be measured and the increase in measurement speed, there has been proposed a measurement apparatus that uses spectral interference and performs measurement for each line (Patent Document 2).

JP 2006-220525 A JP 2012-189406 A

However, in the above document, the object to be measured by the measuring apparatus using spectral interference has a relatively small area such as a wafer or liquid crystal glass. If this measuring device were to be used to measure large-area films, etc., the total thickness data would be too large, with some films being 10 meters or more in width and several thousand meters or more in length. There's a problem. That is, when the thickness data becomes enormous, the display speed of the display unit of the measuring device becomes slow, and the device for storing the data becomes enormous, resulting in the problem that the system of the measuring device becomes too large.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide a thickness measuring apparatus capable of efficiently displaying the data even if the thickness data of the device to be measured becomes enormous.

A thickness measuring device according to a first aspect of the present invention comprises a device main body including a linear light source and an imaging device that receives measurement light emitted from the light source via an object to be measured, and , a control device that calculates the thickness of the object to be measured by analyzing the spectral characteristics of the measurement light, and a display device that displays the thickness calculated by the control device, wherein the imaging device comprises the It has a grating element that disperses measurement light into wavelengths, and the control device controls the grating according to the operation of either the device main body or the object to be measured in a direction perpendicular to the linear direction of the light source. Thickness data, which is the thickness of the object to be measured, is obtained by calculating from the spectral characteristics of the measurement light dispersed by the element, and the thickness data is compressed for each predetermined section of the object to be measured to form compressed data. and displaying the thickness of the object to be measured on a display device based on the compressed data.
A thickness measuring device according to a second invention is characterized in that, in the first invention, the control device calculates an average value for each predetermined section from the thickness data, and uses the average value as the compressed data. .
A thickness measuring apparatus of a third invention is the thickness measuring apparatus according to the first invention or the second invention, wherein when there is unmeasurable data determined to be unmeasurable in the section, the thickness measuring apparatus removes the unmeasurable data. It is characterized by compressing data.
A fourth aspect of the invention is a thickness measuring device according to any one of the first aspect to the third aspect, wherein the control device detects the position of the end of the line-shaped direction of the object to be measured by the imaging device. It is characterized in that it is determined based on the amount of received light.
A thickness measuring device according to a fifth aspect of the invention is the thickness measuring device according to any one of the first to fourth aspects, wherein the control device calculates the position of the end of the object to be measured in the linear direction. It is characterized in that it is determined based on the thickness of the object to be measured.
A sixth aspect of the invention is a thickness measuring device according to any one of the first aspect to the fifth aspect, wherein when the thickness data is abnormal thickness data that does not fall within a predetermined thickness range, the thickness measuring device measures the abnormal thickness The thickness and position of the data and the thickness and position around the abnormal thickness data are displayed with finer resolution than the compressed data.

According to the first invention, when the thickness is measured using the spectral characteristics, the thickness data is compressed for each predetermined section of the object to be measured to obtain compressed data, and the thickness is displayed by the compressed data. As a result, even if the measurement target has a large area, such as a film, the thickness of the entire measurement target can be displayed at high speed.
According to the second invention, by using the average value for each section as the compressed data, the thickness accuracy in the section is improved compared to the case where the median value or the mode value is used as the compressed data.
According to the third aspect of the invention, by removing the non-measurable data determined to be non-measurable and compressing the thickness data, the thickness accuracy in the section is further improved.
According to the fourth invention, the control device determines the position of the end portion of the object to be measured in the width direction based on the amount of received light. becomes clear.
According to the fifth invention, the control device determines the position of the end portion of the object to be measured in the width direction based on the thickness. Or, for any meandering of the coating, which is the object to be measured, the range to be measured of the object to be measured becomes clear.
According to the sixth invention, when abnormal thickness data appears, the control device displays the surrounding data with fine resolution. is displayed at high speed, it is possible to grasp the details of the abnormal portion.

FIG. 4 is an explanatory diagram of a compression method performed by the thickness measuring device according to the first embodiment of the present invention; (A) is an explanatory diagram of the object to be measured that is not divided into intervals, (B) is an explanatory diagram of the object to be measured that is divided into equal intervals, and (C) is an explanation of the object to be measured that is divided into arbitrary intervals FIG. (D) is an explanatory diagram of the object to be measured when there is abnormal thickness data in a part of the section. 1 is a plan view of a thickness measuring device according to a first embodiment of the present invention; FIG. FIG. 3 is a side view of the thickness measuring device of FIG. 2; 3 is a configuration diagram of an imaging device that constitutes the thickness measuring device of FIG. 2. FIG. FIG. 3 is a control block diagram of the thickness measuring device of FIG. 2; It is a side view of the thickness measuring device which concerns on 2nd Embodiment of this invention. 3 is a first operation flow chart of the thickness measuring device of FIG. 2; FIG. 3 is a second operation flow diagram of the thickness measuring device of FIG. 2. FIG. 3 is a third operation flowchart of the thickness measuring device of FIG. 2; FIG. 3 is a fourth operation flow diagram of the thickness measuring device of FIG. 2. FIG. FIG. 5 is a fifth operation flowchart of the thickness measuring device of FIG. 2;

Next, embodiments of the present invention will be described based on the drawings. However, the embodiment shown below is an example of a thickness measuring device for embodying the technical idea of the present invention, and the present invention does not specify the thickness measuring device as follows. Note that the sizes, positional relationships, etc. of members shown in each drawing may be exaggerated for clarity of explanation. In addition, the description "perpendicular" in this specification does not have to be strictly vertical, and in the part where this word is used, it is vertical to the extent that the function of the part can be fully satisfied, that is, "substantially It is meant to include a range that is "perpendicular to the surface".

(Configuration of thickness measuring device 10 of first embodiment)
FIG. 2 shows a plan view of the thickness measuring device 10 according to the first embodiment of the present invention, and FIG. 3 shows a side view thereof. In order to facilitate understanding, only main members of the thickness measuring device 10 are shown in FIGS. A thickness measuring apparatus 10 according to the present invention is a measuring apparatus capable of measuring the thickness of an object to be measured by analyzing the spectral characteristics of measurement light that has passed through the object to be measured. In addition to receiving reflected light reflected from the surface of the object to be measured, the thickness measuring apparatus 10 according to the present invention receives light transmitted through the object to be measured when the object to be measured is transparent. Although there may be cases, the case of receiving reflected light will be described as the first embodiment. In addition, the expression "via the object to be measured" in the claims is used as a broader concept of the expression "transmitting through the object to be measured" or "reflecting from the object to be measured".

An object to be measured by the thickness measuring device 10 according to the present invention is, for example, a resin film 40 having a smooth surface. In FIGS. 2 and 3, a resin film 40 (indicated by a chain double-dashed line in FIG. 2 because it overlaps with other members) is shown as an object to be measured. Note that the object to be measured is not limited to the resin film 40 as long as the spectral characteristics can be analyzed. Examples include glass, a coating formed on the resin film 40, a coating formed on glass, an oxide film or resist on a silicon wafer, and the like.

In this embodiment, as shown in FIG. 3, the resin film 40 is unwound from a supply roller 41 located on the right side of the paper surface of FIG. 3 and wound up by a winding roller 42 located on the left side. In FIG. 3 , the depth direction corresponds to the width direction of the resin film 40 and is the linear direction of the light source 11 . The resin film 40 moves from the right side to the left side as indicated by the arrow at the portion where the thickness is measured by the thickness measuring device 10. In the present embodiment, the supply roller 41 and the take-up roller 42 move the operating device. Configure. That is, in this embodiment, the thickness data of the object to be measured is acquired in accordance with the movement of the resin film 40 to be measured in the direction perpendicular to the linear direction of the light source 11 .

A thickness measuring device 10 according to this embodiment has a device main body. The device main body includes a linear light source 11 and an imaging device 20 that receives the measurement light emitted from the light source 11 via the object to be measured. The line-shaped light source 11 has a line-shaped direction in the horizontal direction in FIG. 2 and in the depth direction in FIG.

In this embodiment, the linear light sources 11 are LEDs. Since the linear light source 11 is an LED, it becomes easy to increase the size of the light source 11, increase the amount of light, and reduce the manufacturing cost. However, the linear light source 11 is not limited to this. For example, a fluorescent lamp, a halogen light source, or a metal halide lamp can be used as long as they are linear. When the linear light source 11 is a halogen light source, it is suitable for thickness measurement because the wavelength of the emitted measurement light is wide and the intensity is constant. It is preferable to use a cylindrical lens or a rod lens at the tip of the linear light source 11 . This is because the amount of light received by the imaging device 20 is increased. Further, it is preferable to irradiate uniform light by installing a plate material having light diffusing property such as a diffuser or a diffusion plate between the light source 11 and the resin film. This is because it is possible to obtain stable measurement results by irradiating light uniformly. Here, in FIG. 2, the dashed-dotted line drawn from the light source 11 to the imaging device 20 represents the measurement light received by the imaging device 20 among the measurement light emitted from the light source 11. , the measurement light emitted from the light source 11 extends to the outside of these solid lines.

FIG. 4 shows a configuration diagram of the imaging device 20 according to this embodiment. FIG. 4 is a cross-sectional view of the imaging device 20 viewed from the side. In FIG. 4, the measuring light is indicated by a one-dot chain line. The imaging device 20 receives measurement light emitted from the linear light source 11 via the object to be measured. Light reception is performed by splitting the measurement light. As shown in FIG. 4, the imaging device 20 includes a first lens 21 that collects the measurement light that has passed through the object to be measured, and an unnecessary portion of the collected measurement light that is cut to improve spectral accuracy. a slit 22, a second lens 23 for correcting the orientation of the measurement light passing through the slit 22 so that it is incident on the grating element 24, a grating element 24 for separating the measurement light into wavelengths, A housing 27 is provided with a third lens 25 for condensing measurement light onto a two-dimensional sensor 26 and a two-dimensional sensor 26 for receiving the divided measurement light.

The two-dimensional sensor 26 has a predetermined length in the left-right direction and the depth direction in FIG. 4, and CMOS is used as the element in this embodiment. However, the elements are not limited to CMOS. For example, CCD, InGaAs, InSb, MCT, QWIP, etc. can be used. When a CCD or CMOS is used as the element of the two-dimensional sensor 26, cooling of the two-dimensional sensor 26 becomes unnecessary, and the manufacturing cost of the thickness measuring device 10 can be suppressed. Especially when CMOS is used, it is possible to perform ROI (Region Of Interest) in both the left, right, and depth directions.

The first lens 21, the second lens 23, and the third lens 25 used in the imaging device 20 do not matter as long as they can condense and manipulate the measurement light. It is also possible to use curved mirrors instead of these lenses. The use of a curved mirror increases the degree of freedom in design, making it possible to downsize the imaging device 20 .

In this embodiment, the grating element 24 is transmissive. However, the present invention is not limited to this, and it is also possible to employ a reflective grating element. Employment of the reflective grating element increases the degree of freedom in design, and makes it possible to reduce the size of the imaging device 20 .

In this embodiment, the housing 27 of the imaging device 20 is made of aluminum. Since the housing 27 is made of aluminum, good heat dissipation and workability can be obtained. Also, it is possible to reduce costs. However, it is not limited to this, and it is also possible to use resin, stainless steel, or the like.

FIG. 5 shows a control block diagram of the thickness measuring device 10 according to this embodiment. The thickness measuring device 10 of this embodiment has a control device 12 . The control device 12 is composed of a CPU and the like. The control device 12 is electrically connected to the light source 11 , imaging device 20 , display device 13 , data storage device 14 and input device 15 . The control device 12 can calculate the thickness of the object to be measured by analyzing the spectral characteristics of the measurement light measured by the two-dimensional sensor 26 of the imaging device 20 .

In this embodiment, the display device 13 is a liquid crystal display, and can display the thickness data of the object to be measured two-dimensionally or three-dimensionally according to a signal from the control device 12 . However, the display device 13 is not limited to a liquid crystal display. For example, an organic EL display etc. correspond.

In this embodiment, the data storage device 14 is a hard disk, and can store compressed data of the thickness data of the object to be measured calculated by the control device 12 . However, the data storage device 14 is not limited to a hard disk. For example, Blu-ray disc drives, SSDs (Solid State Drives), and the like are applicable.

In the present embodiment, the input device 15 is a touch panel, and the user of the thickness measuring device 10 gives commands through the input device 15, so that the control device 12 controls the light source 11, the imaging device 20, and the operating device. . However, the input device 15 is not limited to a touch panel. For example, keyboard and mouse.

(Operation flow of the thickness measuring device 10 of the first embodiment)
FIG. 7 shows a first operation flowchart of the thickness measuring device 10 according to this embodiment. This first operation flow diagram is a flow in which the control device 12 that has received the measurement data from the two-dimensional sensor 26 of the imaging device 20 deletes the non-measurable data from the measurement data when there is non-measurable data.

From step 101 (hereinafter described as S101), the control device 12 starts the operation flow. The i-th data is the i-th data from the end in the width direction of the object to be measured in one line in the longitudinal direction of the object to be measured. That is, i=1 means the first data from the end in the width direction.

In S102, the control device 12 acquires this i-th spectral characteristic. Since it is a spectral characteristic, the control device 12 acquires the characteristic for each wavelength of the i-th point on one line of the object to be measured.

In S103, the control device 12 calculates, from the i-th spectral characteristic, the peak intensity and the thickness of the object to be measured, which are indicators of the accuracy of the thickness calculation result. The peak intensity and the thickness of the object to be measured are obtained by calculating the reflectance obtained from the i-th spectral characteristic. The reflectance of the i-th positioned point is calculated based on the reference data. That is, the reflectance is obtained by dividing the measured data obtained from the object to be measured by the measured data from the reference material such as aluminum, glass, diffusion plate, plastic, or the like. By performing FFT analysis of this reflectance, the peak intensity and the thickness of the object to be measured are calculated.

In the present embodiment, unmeasurable data that is determined to be unmeasurable includes data in which the peak intensity is equal to or less than the threshold and the thickness of the object to be measured is outside the range input by the user from the input device 15. means data. In S104, the control device 12 determines whether the peak intensity of the measurement light is greater than or equal to the threshold. If the peak intensity is greater than or equal to the threshold, the controller 12 advances the operation flow to S105. If the peak intensity is smaller than the threshold, the controller 12 advances the operation flow to S107.

In S105, the control device 12 determines whether the thickness of the object to be measured is within a predetermined range. For example, the user of the thickness measuring device 10 inputs the numerical values within the predetermined range from the input device 15 in advance. If the thickness of the object to be measured is within the predetermined range, the control device 12 advances the operation flow to S106. If the thickness of the object to be measured is not within the predetermined range, the control device 12 advances the operation flow to S107.

In S106, the controller 12 sets the calculated thickness as thickness data Thick(i). In S107, the controller 12 treats the calculated thickness as an error.

At S108, the controller 12 determines whether the i-th located point is located at the highest numbered portion, ie, the end, of a line of the object under test. If the controller 12 determines that the i-th located point is at the edge, the controller 12 terminates this operational flow. When the control device 12 determines that the i-th point has not reached the end, the operation flow proceeds to S109, the i+1-th point is set as the i-th point, and the operation flow is repeated. Run.

By removing the non-measurable data determined to be non-measurable as described above and compressing the thickness data, the thickness accuracy in the section is further improved.

FIG. 8 shows a second operation flowchart of the thickness measuring device 10 according to this embodiment. This second operation flow diagram is an operation flow for compressing the thickness data for each predetermined section of the object to be measured using the thickness data after the first operation flow, for example, to obtain compressed data. As shown in FIGS. 1(A) and 1(B), the thickness measuring apparatus 10 according to the present embodiment measures an object to be measured, which is not divided into sections as shown in FIG. 1(A), as shown in FIG. Then, the thickness data in each section is compressed, and the compressed data is used as the thickness of the entire section. As for the size of the sections, there are cases where the sections are divided evenly as shown in FIG. 1B, and sections which are divided into an arbitrary size as shown in FIG. The case of dividing into an arbitrary size corresponds to the case of wanting to see finely only the peripheral area where the film thickness variation is large, or the case of setting according to the interval when cutting is performed in a post-process. Here, the "predetermined section" may be initially set by the user of the thickness measuring device 10, or may be determined by the control device 12 from the position of the end of the object to be measured, which will be described later. The former has the advantage that the linear absolute position of the object to be measured can be known, and the latter has the advantage that the section can be set with the object to be measured as a reference.

The ratio of the compressed data to the thickness data, ie, the compression ratio, is preferably half or less of the original data, more preferably 1/100 or less, and particularly preferably 1/10000 or less.

Although FIG. 1 shows the thickness data of the object to be measured, the film thickness distribution may be displayed on the entire screen of the display device 13 (see FIG. 5), or may be displayed on a part of the screen. It's okay to be. In addition, the film thickness can be displayed by a display method in which the film thickness and the color or shade are associated with each other. Compared to the case of displaying all the film thickness distributions measured before compression shown in FIG. 1A, the number of data for display in FIG. be done.

In the following description of the second operation flow in FIG. 8, the case where the thickness data after the first operation flow is used will be described, but the present invention is not particularly limited to this. For example, although non-measurable data is removed in the first operation flow, there may be cases where non-measurable data is not removed. It is also possible to use thickness data after the third operation flow or the fourth operation flow, which will be described later, has been performed.

In S201, the control device 12 starts the second operation flow. First, the control device 12 reads thickness data Thick(k) in the target section.

In S202, the controller 12 sets k=0. The k-th data is data numbered in a predetermined section of the object to be measured. The numbers are from 1 to kmax.

In S203, the control device 12 sets the k+1th data as the kth data. Then, in S204, the control device 12 determines whether the k-th data is kmax+1, which is the highest numbered kmax in the target section plus 1. When the control device 12 determines that the k-th data is kmax+1, the control device 12 advances the operation flow to s207. If the control device 12 determines that the k-th data is not kmax+1, the control device 12 advances the operation flow to S205.

In S205, when the control device 12 determines that Thick(k) of the thickness data is error, the control device 12 returns the operation flow to S203 and performs the operation flow from S203 again. When the control device 12 determines that Thick(k) of the thickness data is not an error, it adds Thick(k) to the total value SumThick of the thickness data and adds 1 to Num, which is the number of thickness data.

In S204, when the control device 12 advances the operation flow to S207, the control device 12 compresses the thickness data of this section to obtain compressed data. In this embodiment, the compression method calculates the average value Ave and uses it as compressed data.

Note that the thickness data compression method is not limited to the method of taking the average value. For example, median, mode, maximum, and minimum values can be used as compressed data. It is also possible to select one that has undergone filtering.

By using the average value for each section as compressed data, the thickness accuracy in the section is improved compared to the case where the median value or the most frequent value is used as compressed data.

FIG. 9 shows a third operation flowchart according to this embodiment. The third operational flow is an operational flow for determining the end of the section in the object to be measured. Thickness data is compressed using the end of the section determined by this operation flow. For example, when the object to be measured meanders, the positions of the ends of the object to be measured in the width direction change. In the third operation flow, even if the object to be measured meanders, the end of the object to be measured is identified, and the end of the section is determined accordingly.

The third operation flow is performed based on the amount of received measurement light. When the measurement light is received by reflection from the object to be measured, it is determined that the object to be measured exists in a place where the amount of received light is high. It becomes possible to determine at which position the measurement target exists.

From S301, the control device 12 starts the operation flow. The i-th data is the i-th data from the end position where the imaging device 20 can receive light in the width direction of the object to be measured in one line in the longitudinal direction of the object to be measured. That is, i=1 means the 1st data from the position of the most receivable edge in the width direction. Since S301 is the beginning of the operation flow, the i-th is the 0th in S301.

In S302, the control device 12 sets the i+1-th data as the i-th data. Then, in S<b>303 , the control device 12 acquires the i-th received light amount from the two-dimensional sensor 26 .

In S304, the control device 12 determines whether or not the acquired amount of received light is greater than or equal to the threshold. If the amount of received light is greater than or equal to the threshold, the control device 12 advances the operation flow to S305. If the received light amount is not equal to or greater than the threshold, the control device 12 advances the operation flow to S309. The threshold in S304 can be input in advance from the input device 15 by the user of the thickness measuring device 10 . The i-th data is the i-th data from the end position where the imaging device 20 can receive light in the width direction of the object to be measured in one line in the longitudinal direction of the object to be measured. If the amount of received light is not equal to or greater than the threshold, it is determined that the data is not the edge of the object to be measured, and the control device 12 advances the operation flow to S309.

In S309, the control device 12 determines whether i is imax, that is, the maximum possible value of i. If i is not imax, the controller 12 returns the operation flow to S302. If i is imax, the controller 12 advances the operational flow to S312.

In S305, the control device 12 determines that the amount of light received by the i-th data exceeds the threshold for the first time, and assumes that the position of the end of the line-shaped direction of the object to be measured, that is, the EdgeFront is the i-th position. .

In S306, the control device 12 sets the i+1-th data as the i-th data. Then, in S307, the control device 12 determines whether or not the acquired amount of received light is equal to or less than the threshold. If the received light amount is equal to or less than the threshold, the control device 12 advances the operation flow to S308. If the received light amount is not equal to or less than the threshold, the control device 12 advances the operation flow to S310. The threshold in S307 can be input in advance from the input device 15 by the user of the thickness measuring device 10, as in S304.

In S310, the controller 12 determines whether i is imax, i.e., the maximum possible value of i. If i is not imax, the controller 12 returns the operation flow to S306. If i is imax, the controller 12 advances the operation flow to S311.

In S308, the control device 12 determines that the amount of light received by the i-th data, which had been above the threshold until then, has become below the threshold, and the position of the end of the linear direction of the object to be measured, that is Let EdgeEnd be the ith position.

In S311 and S312, the control device 12 assumes that EdgeFront and EdgeEnd are error, assuming that the edge of the object to be measured does not exist within the position where the imaging device 20 can receive light in the width direction of the object to be measured.

After this third operation flow is finished, the above-described second operation flow can be executed.

By determining the position of the end portion in the width direction of the object to be measured based on the amount of received light, the range to be measured of the object to be measured becomes clear even when the object to be measured meanders.

In addition to the simple threshold determination of the amount of received light as described above, the determination of the position of the end portion using the amount of received light can be performed by performing threshold determination after processing using a filter, or by determining the threshold using values of multiple frames. A process of making a determination after averaging is applicable.

FIG. 10 shows a fourth operation flowchart according to this embodiment. A fourth operation flow is an operation flow for determining the end of the section in the object to be measured. Thickness data is compressed using the end of the section determined by this operation flow. For example, if the object to be measured is a coating, the edge of the object to be measured is determined for either the meandering of the object itself or the meandering of the coating, which is the object to be measured. is determined.

More specifically, when a base material such as a film is coated, the coating is rarely applied to the edges of the base material, and there are usually uncoated sections at the edges of the base material. In the judgment in the third operation flow described above, it is possible to distinguish the presence or absence of the base material, but it is difficult to distinguish the presence or absence of the coating on it. It is not possible to know the exact location of the ends of the directions.

Therefore, it is possible to accurately obtain the position of the coating in the width direction by determining the position of the end portion in the width direction of the object to be measured from the film thickness result. For example, if the position of the end portion in the width direction of the object to be measured is determined based on the film thickness of the object coating being equal to or greater than a threshold value, the position of the coating can be used as a reference.

From S401, the control device 12 starts the operation flow. The i-th data is the i-th data from the end position where the imaging device 20 can receive light in the width direction of the object to be measured in one line in the longitudinal direction of the object to be measured. That is, i=1 means the 1st data from the position of the most receivable edge in the width direction. Since S401 is the beginning of the operation flow, the i-th becomes the 0th in S401.

In S402, the control device 12 sets the i+1-th data as the i-th data. Then, in S403, the control device 12 acquires the i-th spectral characteristic from the two-dimensional sensor 26, and the control device 12 calculates the thickness at the i-th position based on the obtained spectral characteristic.

In S404, the control device 12 determines whether the calculated thickness is equal to or greater than the threshold. If the thickness is equal to or greater than the threshold, the control device 12 advances the operation flow to S405. If the thickness is not equal to or greater than the threshold, the control device 12 advances the operation flow to S409. The user of the thickness measuring device 10 can input the threshold in S404 from the input device 15 in advance. The i-th data is the i-th data from the end position where the imaging device 20 can receive light in the width direction of the object to be measured in one line in the longitudinal direction of the object to be measured. If the thickness is not equal to or greater than the threshold, it is determined that the data is not the edge of the object to be measured, and the control device 12 advances the operation flow to S409.

In S409, the control device 12 determines whether or not i is imax, that is, the maximum possible value of i. If i is not imax, the controller 12 returns the operation flow to S402. If i is imax, the controller 12 advances the operational flow to S412.

In S405, the control device 12 determines that the thickness at the i-th position is equal to or greater than the threshold for the first time, and assumes that the position of the edge of the line-shaped object to be measured, that is, the EdgeFront is the i-th position.

In S406, the control device 12 sets the i+1th data as the ith data. Then, in S407, the control device 12 determines whether the calculated thickness is equal to or less than the threshold. If the thickness is equal to or less than the threshold, the control device 12 advances the operation flow to S408. If the thickness is not equal to or less than the threshold, the control device 12 advances the operation flow to S410. The threshold in S407 can be input in advance from the input device 15 by the user of the thickness measuring device 10, as in S404.

In S410, the control device 12 determines whether i is imax, that is, the maximum possible value of i. If i is not imax, the controller 12 returns the operation flow to S406. If i is imax, the controller 12 advances the operation flow to S411.

In S408, the control device 12 determines that the thickness in the i-th data, which was the threshold value or more until then, has become the threshold value or less, and determines the position of the end of the line-shaped direction of the object to be measured, that is, EdgeEnd be the i-th position.

In S411 and S412, the control device 12 assumes that EdgeFront and EdgeEnd are error, assuming that the edge of the object to be measured does not exist within the position where the imaging device 20 can receive light in the width direction of the object to be measured.

After this fourth operation flow is finished, the above-described second operation flow can be executed.

When the object to be measured is a coating, the range to be measured of the object to be measured becomes clear for both the meandering of the object itself and the meandering of the coating that is the object to be measured.

Note that the determination of the position of the end portion using the thickness of the object to be measured can be performed by performing threshold value determination after processing using a filter, in addition to the simple threshold value determination of the thickness of the object to be measured as described above. , or a process of averaging the values of a plurality of frames before making a determination, or the like can be applied. Moreover, when the object to be measured has a plurality of layers, it is also possible to perform the above determination processing on any layer or the total of all layers.

FIG. 11 shows a fifth operation flowchart of the thickness measuring device 10 according to this embodiment. In this fifth operation flow chart, when the controller 12 receives the measurement data from the two-dimensional sensor 26 of the imaging device 20 and the abnormal thickness data does not fall within a predetermined range, the position and This is an operation flow for leaving the peripheral thickness data without compression. This operational flow can be executed, for example, before the second operational flow, or between the first operational flow and the second operational flow, or in parallel therewith. For example, FIG. 1(D) shows an object to be measured with abnormal thickness data.

In S501, the control device 12 reads thickness data in the target section.

At S502, controller 12 filters the thickness data. This filter can be, for example, a dilation filter, an erosion filter, an averaging filter, a median filter, a Sobel filter, a Prewitt filter, a Laplacian filter, a Gaussian filter, a bilateral filter, an unsharp masking filter, or any other spatial filter depending on the object. It is possible.

In S503, the control device 12 binarizes the thickness data using the predetermined thickness range as a threshold value. Then, in S504, the control device 12 acquires the position where it is determined that there is abnormal thickness data. Then, from the thickness and position of the abnormal thickness data, the length, width, area, etc. of the abnormal portion are calculated.

In S505, the control device 12 determines the length, width, etc. of the binarized thickness data to determine whether or not it is abnormal thickness data. If the control device 12 does not determine that the thickness data is abnormal, the fifth operation flow ends. When the control device 12 determines that the thickness data is abnormal, the control device 12 advances the operation flow to S506.

In S<b>506 , the control device 12 accumulates the thickness and position of the abnormal thickness data and the thickness and position around the abnormal thickness data in the data accumulation device 14 . Here, "periphery of the abnormal thickness data" means the vicinity of the position of the abnormal thickness data, and may be determined for each section or "periphery of the abnormal thickness data" regardless of the section. For example, it corresponds to a few centimeters around the position of the abnormal thickness data. Also, the thickness and position of the abnormal thickness data and the thickness and position around the abnormal thickness data are stored with finer resolution than the compressed data.

In the fifth operation flow described above, from the measurement result of the thickness data of the object to be measured, the location where the thickness abnormality occurs is determined, and the film thickness distribution around the location is stored. Then, the data is stored with finer resolution than the compressed data. As a result, the shape, size, thickness, etc. of the abnormal portion can be understood in detail, and the cause of the abnormality can be easily identified.

Further, by excluding the abnormal thickness data determined to be abnormal here from the compressed data, it is possible to prevent the accuracy of the result of the compression processing from being lowered due to the abnormal thickness data.

Although the first operation flow to the fifth operation flow have been described, these can be executed singly or in combination with the thickness measuring device 10 of the present embodiment. For example, the thickness measuring device 10 performs the third operation flow alone, the thickness measuring device 10 performs the fourth operation flow alone, the first operation flow is performed, the third operation flow is performed, and then the second operation flow is performed. can also be a thickness measuring device 10 that performs Then, the control device 12 compresses the thickness data into compressed data, and displays the thickness of the object to be measured on the display device 13 based on this compressed data. It is also possible to process them in parallel.

When measuring the thickness using the spectral characteristics, the thickness data is compressed for each predetermined section of the object to be measured to obtain compressed data. Even if the target to be measured has a large area, the film thickness of the entire target to be measured can be displayed at high speed.

When abnormal thickness data appears, the surrounding data is displayed with fine resolution. can grasp the details.

(Configuration of thickness measuring device 10 of second embodiment)
FIG. 6 shows a schematic side view of the thickness measuring device 10 according to the second embodiment of the present invention. In the first embodiment, the imaging device 20 receives the measurement light reflected from the object to be measured, whereas in the second embodiment, the imaging device 20 receives the measurement light transmitted through the object to be measured. is. As shown in FIG. 6, the thickness measuring apparatus 10 according to the second embodiment has a light source 11 for irradiating the object to be measured with measurement light and the measurement light from the object to be measured. An imaging device 20 for receiving light and a control device 12 for calculating the thickness based on a signal from the imaging device 20 are provided. In this embodiment, the line connecting the light source 11 and the imaging device 20 intersects the object to be measured perpendicularly.

(others)
When a portion with abnormal thickness data is specified by executing the fifth operation flow, it is also possible to display the portion with abnormal thickness data like a marker on the film thickness distribution display after compression. be. Furthermore, it is possible to have a function of displaying thickness data around the abnormal thickness data by clicking on the display. In addition, it is also possible to directly display the portion of the abnormal thickness data on the film thickness distribution display after compression, and to display the details by enlarging it. It is also possible to list and display only the film thickness distribution around the abnormal thickness data.

A plurality of imaging devices 20 may be installed such that the long axis direction of the measurement range is perpendicular to the transport direction, that is, the longitudinal direction of the object to be measured. It should be noted that there is no problem even if the imaging devices 20 are shifted in the width direction and the transport direction when a plurality of imaging devices 20 are installed. In this case, it is possible to measure a wide object to be measured even if the length of the LED is limited.

The operation flow of the thickness measuring device 10 can be realized by software or by hardware. When implemented in hardware, image display processing and the like can be performed at high speed.

Moreover, in the measurement with the thickness measuring device 10, the case where the object to be measured moves has been described, but the present invention is not limited to this. For example, it is possible to operate the device main body by a motion device comprising a ball screw and a linear guide.

REFERENCE SIGNS LIST 10 thickness measuring device 11 light source 12 control device 13 display device 20 imaging device

Claims (6)

a device main body composed of a linear light source and an imaging device that receives measurement light emitted from the light source via an object to be measured;
a control device that calculates the thickness of the object to be measured by analyzing the spectral characteristics of the measurement light obtained from the imaging device;
and a display device that displays the thickness calculated by the control device,
The imaging device has a grating element that disperses the measurement light by wavelength,
The control device controls the measurement target from the spectral characteristics of the measurement light dispersed by the grating element in accordance with the operation of either the device main body or the measurement target in a direction perpendicular to the linear direction of the light source. Calculate and acquire thickness data, which is the thickness of the object,
compressing the thickness data for each predetermined section of the object to be measured to obtain compressed data;
Displaying the thickness of the object to be measured on a display device based on the compressed data;
A thickness measuring device characterized by: The control device calculates an average value for each predetermined section from the thickness data, and uses the average value as compressed data.
The thickness measuring device according to claim 1, characterized in that: When there is unmeasurable data determined to be unmeasurable in the section, the control device
compressing the thickness data, excluding the non-measurable data;
The thickness measuring device according to claim 1 or 2, characterized in that: The control device is
The position of the end of the line-shaped direction of the object to be measured is
determined based on the amount of light received by the imaging device;
The thickness measuring device according to any one of claims 1 to 3, characterized in that: The control device is
The position of the end of the line-shaped direction of the object to be measured is
determined based on the thickness of the object to be measured calculated by the control device;
The thickness measuring device according to any one of claims 1 to 4, characterized in that: The control device is
When the thickness data is abnormal thickness data that is not within a predetermined thickness range,
displaying the thickness and position of the abnormal thickness data and the thickness and position around the abnormal thickness data with finer resolution than the compressed data;
The thickness measuring device according to any one of claims 1 to 5, characterized in that:

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