JP7076280B2 - Measuring method and measuring device - Google Patents

Description

The present invention relates to a technique for acquiring an image from a sheet-shaped or plate-shaped object, and the acquired image is preferably used to acquire the characteristics of changes in the thickness and surface shape of the object. ..

Conventionally, a technique for continuously manufacturing a sheet-shaped or plate-shaped member has been known. For example, in the roll forming apparatus of Patent Document 1, the molten resin extruded from the die is continuously conveyed while being sandwiched between the rolls, and a sheet is formed.

On the other hand, various techniques for inspecting continuously manufactured sheets have also been proposed. For example, in the inspection method of Patent Document 2, a sheet-like film is arranged at an angle with respect to the screen between the light source and the screen, and the screen is photographed, resulting in gentle wavy irregularities on the film surface. The resulting uneven thickness of the film is inspected. In the defect state detection method of Patent Document 3, a straight tube fluorescent tube is arranged at an angle with respect to the width direction of the transparent adhesive sheet body, and a shadow of a streak defect portion along the length direction of the sheet is detected by a camera. Is disclosed.

Japanese Unexamined Patent Publication No. 2010-46798 Japanese Unexamined Patent Publication No. 2007-211092 Japanese Unexamined Patent Publication No. 5-180785

By the way, when a sheet or a plate is manufactured while being continuously conveyed, a change in the thickness or surface shape of a convex or concave shape extending in the width direction appears due to various factors. Changes in thickness or surface shape may be assessed as defects or as a level of product quality. In either case, by acquiring the characteristics of variation in light transmission or reflection, it is possible to investigate the cause of the change, adjust the device to reduce the change, and determine whether there is room to reduce the change. It is expected that the acquired characteristics will be useful.

The present invention has been made in view of the above problems, and an object of the present invention is mainly to obtain an image showing the characteristics of variation in light transmission or reflection in a sheet-shaped or plate-shaped object.

The invention according to claim 1 is a measuring method for obtaining a measured value indicating the characteristics of the object from a sheet-shaped or plate-shaped object manufactured while being continuously conveyed in the conveying direction, a). The surface of the object is perpendicular to a predetermined XY plane, the transport direction is parallel to the XY plane, and the angle formed by the normal line of the surface of the object and the X direction is The step of arranging the object so as to have a predetermined angle, b) the step of irradiating the object with light parallel to, converging or diverging in the Y direction from the X direction, and c) transmitting or transmitting the object. A step of acquiring an image by acquiring an image of reflected light projected on a screen, or by receiving light transmitted or reflected from the object, and d) the said in a direction corresponding to the transport direction. While maintaining the step of acquiring the maximum value of the brightness change of the image and e) the plane of the object being perpendicular to the XY plane and the transport direction being parallel to the XY plane. By repeating the steps b) to d) while changing the angle formed by the normal line of the surface of the object and the X direction, a plurality of images are acquired and the brightness of each of the plurality of images is obtained. It includes a step of acquiring the maximum value of change, and f) a step of acquiring the relationship between the angle formed by the normal line of the surface of the object and the X direction and the maximum value of the brightness change .

The invention according to claim 2 is the measuring method according to claim 1 , wherein in the step e ), the object is rotated about an axis perpendicular to the XY plane.

The invention according to claim 3 is the measuring method according to claim 1 or 2, wherein in the step e), the angle between the normal of the surface of the object and the X direction is 15 degrees or less. The steps b) to d) are repeated while changing only the angle of.

The invention according to claim 4 is a measuring device for acquiring a measured value indicating the characteristics of the object from a sheet-shaped or plate-shaped object manufactured while being continuously conveyed in the transport direction. While maintaining a state in which the surface of the object is perpendicular to the predetermined XY plane and the transport direction is parallel to the XY plane, the normal line of the surface of the object and the X direction are formed. A holding unit that holds the object so that the angle can be changed relatively, an illuminating unit that irradiates the object with light parallel to, converging, or diverging in the Y direction from the X direction, and transmitting the object. Alternatively, the image pickup unit that acquires an image by acquiring an image of the reflected light projected on the screen, or by receiving the light transmitted or reflected from the object, and the imager in a direction corresponding to the transport direction. It includes a calculation unit that acquires the maximum value of the change in brightness of an image, a control unit that controls the image pickup unit and the holding unit, and the holding unit controls the normal to the surface of the object by the control of the control unit. A plurality of images are acquired by the imaging unit repeatedly acquiring images while changing the angle between the image and the X direction, and the arithmetic unit acquires the maximum value of the brightness change of each of the plurality of images. Then, the relationship between the angle formed by the normal line of the surface of the object and the X direction and the maximum value of the change in brightness is acquired .

The invention according to claim 5 is the measuring device according to claim 4 , wherein the holding portion rotates the object around an axis perpendicular to the XY plane.

The invention according to claim 6 is the measuring device according to claim 4 or 5 , wherein the angle formed by the normal line of the surface of the object and the X direction is controlled by the control unit. The plurality of images are acquired while changing only the angle of 15 degrees or less .

According to the present invention, it is possible to obtain an image showing the characteristics of variation in light transmission or reflection of an object in the transport direction.

It is a front view of the measuring device. It is a top view of the image acquisition device. It is a schematic diagram which shows the state that the object is manufactured. It is a figure which shows the object. It is a figure which shows the flow of operation of a measuring device. It is a figure which shows an example of the acquired image. It is a figure which shows the image processing range enlarged. It is a figure which shows an example of the brightness change. It is a figure which exemplifies the relationship between the rotation position and the maximum change value of brightness. It is a top view which shows the other image acquisition apparatus.

FIG. 1 is a front view showing a measuring device 1 according to the first embodiment of the present invention. The measuring device 1 includes an image acquisition device 11, a computer 12, and a display 13. FIG. 2 is a plan view of the image acquisition device 11. In FIGS. 1 and 2, for convenience of explanation, the X direction, the Y direction, and the Z direction are shown. The X, Y and Z directions are perpendicular to each other. The object 9 to be measured is a sheet-shaped or plate-shaped member manufactured while being continuously transported in a predetermined transport direction. The object 9 is formed of, for example, a resin. The object 9 is preferably a plastic product that is a substitute for the glass for a touch panel, but the use of the object 9 is not limited to this. The object 9 may be molded from a material other than the resin. In the first embodiment, the object 9 is transparent, and both main surfaces of the object 9 are substantially flat.

As shown in FIGS. 1 and 2, the image acquisition device 11 controls the holding unit 21 that holds the object 9, the lighting unit 22 that irradiates the object 9 with light, the screen 23, and the image pickup unit 24. Including part 25. In FIG. 2, the control unit 25 is not shown. The holding portion 21 holds the object 9 so that the surface of the object 9 is perpendicular to the XY plane and the direction corresponding to the transport direction at the time of manufacture on the object 9 is parallel to the XY plane. Hold. The "face" of the object 9 is the largest surface of the object 9. The XY plane is a predetermined virtual plane parallel to the X and Y directions.

The holding unit 21 includes a frame 211 for holding the object 9 and a motor 212. The motor 212 rotates the frame 211 about the axis J1 parallel to the Z direction, that is, perpendicular to the XY plane. The holding portion 21 holds the object 9 so that the angle formed by the normal of the surface of the object 9 and the X direction can be relatively changed. In FIG. 2, a two-dot chain line shows how the frame 211 rotates.

The illumination unit 22 includes a light source 221, a light emission unit 222, and a lens 223. In FIG. 2, the light source 221 is not shown. The optical axis J2 of the illumination unit 22 is parallel to the X direction, that is, perpendicular to the YZ plane. In this embodiment, the light source 221 is an LED. Other light sources 221 may be used. The light generated by the light source 221 is guided to the light emitting unit 222 via the optical fiber. The light emitting unit 222 emits light from the pinhole. That is, the light emitting unit 222 is a point light source. The light source 221 and the light emitting unit 222 may be one unit. The light emitted from the light emitting unit 222 is converted into parallel light 71 by the lens 223. In FIGS. 1 and 2, the components that hold the light emitting unit 222 and the lens 223 are not shown.

The illumination unit 22 irradiates the object 9 with the parallel light 71 from the X direction. The light transmitted through the object 9 is guided to the screen 23. As a result, the light transmitted through the object 9 is projected onto the screen 23. The image pickup unit 24 acquires the image projected on the screen 23. To be precise, the imaging unit 24 acquires data representing an image of the object 9 projected on the screen 23. The image pickup unit 24 images the screen 23 from a position that does not interfere with the frame 211 of the holding unit 21. Since the image pickup unit 24 captures the screen 23 from diagonally above, the acquired image is corrected so as to have the same shape as when the screen 23 is captured from the front. In FIGS. 1 and 2, the components supporting the screen 23 and the image pickup unit 24 are omitted. The control unit 25 controls the motor 212 and the image pickup unit 24 of the holding unit 21.

FIG. 3 is a schematic view showing how the object 9 is manufactured. FIG. 3 shows a state of being manufactured by the manufacturing method disclosed in Japanese Patent Application Laid-Open No. 2010-46798, but the manufacturing method of the object 9 is not limited to this method. The sheet-shaped molten resin extruded from the die 81 is first guided into the gap between the high-rigidity main roll 82 and the first metal elastic roll 83. The resin is formed by being sandwiched between the main roll 82 and the first metal elastic roll 83, and is conveyed on the main roll 82 by the rotation of the main roll 82. The resin is further guided into the gap between the main roll 82 and the second metal elastic roll 84, sandwiched between the main roll 82 and the second metal elastic roll 84, and further formed.

The resin is conveyed on the second metal elastic roll 84 by the rotation of the second metal elastic roll 84, becomes a continuous object 90, and is conveyed in the transfer direction indicated by reference numeral 91. A part of the object 90 is cut out to be the object 9 shown in FIGS. 1 and 2.

FIG. 4 is a diagram showing an object 9. A reference numeral 91 is attached to an arrow indicating a direction corresponding to the transport direction 91 in FIG. In the following description, the direction on the object 9 corresponding to the transport direction 91 is also referred to as “transport direction 91”. Further, the direction parallel to the surface of the object 9 and perpendicular to the transport direction 91 is called the width direction 92. In FIGS. 1 and 2, the width direction 92 is perpendicular to the XY plane.

FIG. 5 is a diagram showing an operation flow of the measuring device 1. First, the object 9 is attached to the frame 211 of the holding portion 21. As described above, the plane of the object 9 is perpendicular to the XY plane, and the transport direction 91 is parallel to the XY plane. The control unit 25 rotates the motor 212, and the object 9 is arranged at a predetermined initial rotation position. As a result, the object 9 is arranged so that the angle formed by the normal of the surface of the object 9 and the X direction is the initial first angle (step S11). The normal of the surface of the object 9 (to be exact, the normal direction) is not the normal in the exact sense of each position on the surface, but the approximate normal of the surface of the object 9 held by the frame 211. It points in a direction and is a fixed direction with respect to the rotation axis of the frame 211 or the motor 212.

The light generated by the light source 221 is emitted from the light emitting unit 222, and the parallel light 71 irradiates the object 9 from the X direction (step S12). Of course, the order of step S11 and step S12 may be interchanged. By irradiating the object 9 with light, the light transmitted through the object 9 is projected onto the screen 23 to form a projected image of the object 9. Under the control of the control unit 25, the image pickup unit 24 acquires an image of the projected image (step S13). The image data is stored in the storage unit of the computer 12 via the control unit 25.

The control unit 25 rotates the motor 212 to arrange the object 9 at the next rotation position. As a result, the object 9 is arranged so that the angle formed by the normal of the surface of the object 9 and the X direction is the second angle (steps S14 and S15). Since the object 9 rotates about the axis J1, the state in which the surface of the object 9 is perpendicular to the XY plane and the transport direction 91 is parallel to the XY plane is maintained. By executing the image acquisition by the image pickup unit 24 again, the data of the second image is stored in the storage unit of the computer 12 (step S13).

By the control of the control unit 25, the image pickup by the image pickup unit 24 is repeated while changing the second angle formed by the surface of the object 9 and the X direction (steps S13 to S15). As a result, a plurality of images are acquired and the data is stored in the computer 12. After that, the irradiation of the object 9 with the light by the lighting unit 22 is stopped (step S16).

The pitch of the rotation angle of the object 9 in step S15 is preferably 15 degrees or less. Further, the pitch of the rotation direction and the rotation angle can be changed in various ways, but preferably, the pitch of the rotation direction and the rotation angle is constant. In the above description, the first angle formed by the normal of the surface of the object 9 and the X direction is referred to as a "first angle", and the second and subsequent angles are referred to as a "second angle". , These are expressions for convenience of explanation and do not necessarily have to be distinguished. The same applies to the following other embodiments.

FIG. 6 is a diagram showing an image 60 which is an example of the acquired image. The lateral direction 61 in FIG. 6 is a direction corresponding to the transport direction 91 on the object 9. The vertical direction 62 is a direction corresponding to the width direction 92 of the object 9. In FIG. 6, the appearance of a large number of streaks extending in the vertical direction 62 in the image 60 is represented by a large number of broken lines extending in the vertical direction 62. These streaks are caused by changes in the thickness or surface shape of the object 9 in the transport direction 91. Since the streaks extend in the width direction 92 of the object 9, they are hereinafter referred to as "horizontal streaks".

The rectangle indicated by reference numeral 63 indicates an area of the image 60 to be processed by the arithmetic unit 121 of the computer 12. Hereinafter, this area 63 is referred to as an “image processing range”. FIG. 7 is an enlarged view showing the image processing range 63. The image processing range 63 is divided into a large number of elongated unit regions 64 extending in the vertical direction 62. A large number of unit regions 64 are arranged in the horizontal direction 61. The width of one unit area 64 in the horizontal direction 61 is one pixel or more, and in the present embodiment, four pixels are arranged in the horizontal direction 61 in each unit area 64.

The calculation unit 121 obtains the average of the pixel values of each unit area 64 as the brightness of the unit area 64. In reality, corrections are made to eliminate the non-uniformity of the intensity of the illumination light and the influence of the optical system. Specifically, the image pickup unit 24 acquires an image of the screen 23 in advance in a state where the object 9 does not exist. The calculation unit 121 obtains the brightness of each unit area 64 in the image as the reference brightness. Then, the brightness of each unit region 64 in the image acquired in the presence of the object 9 is divided by the reference brightness. This gives the corrected brightness. The corrected brightness indicates the transmittance of the region on the object 9 corresponding to the unit region 64. In the following description, the corrected brightness is simply referred to as "brightness".

The calculation unit 121 performs the above calculation on a plurality of images acquired by repeating step S13. As a result, the change in brightness in the lateral direction 61 of each image, that is, the direction corresponding to the transport direction 91 is acquired (step S17). FIG. 8 is a diagram showing an example of a change in brightness. The horizontal axis indicates the number of the unit area 64, and the vertical axis indicates the brightness. From FIG. 8, it can be seen that the brightness has changed for some reason. It can also be seen that the change in brightness has a certain degree of periodicity.

The calculation unit 121 obtains the maximum value of the change in brightness in each image. Various changes in lightness can be used, but in the present embodiment, the difference in lightness between the unit regions 64 adjacent to each other, that is, the absolute value of the value obtained by subtracting the lightness of one from the lightness of the other is the absolute value. Obtained as a change in brightness. Then, the maximum value of the change in brightness is acquired from each image. Hereinafter, the maximum value of the change in brightness is referred to as "contrast". Since each image corresponds to each rotation position, the relationship between the rotation position and the contrast can be obtained by obtaining the contrast of each image acquired from one sample of the object 9.

FIG. 9 is a diagram illustrating the relationship between the rotation position of the object 9 and the contrast. The information shown in FIG. 9 is displayed on the display 13 of FIG. 1 (step S18). Reference numerals 901, 902, and 903 indicate measurement results for different objects 9. However, FIG. 9 does not accurately represent the actually obtained measurement result, and draws a typical relationship of contrast with respect to the rotation position based on the actual measurement result. Since the rotation position indicates the angle formed by the normal line of the surface of the object 9 and the X direction, the rotation position is also hereinafter referred to as an “incident angle”. The incident angle of 0 degrees is a state in which the parallel light 71 is vertically incident on the object 9.

In general, the contrast increases as the angle of incidence increases. This is because as the angle of incidence of the illumination light on the object 9 increases, the difference in brightness between the adjacent unit regions 64 increases. However, when the length of one cycle of the brightness change is short, if the incident angle of the illumination light becomes too large, the length of one cycle is included in one unit region 64, and the change in brightness is conversely reduced. do. As a result, the contrast is reduced.

In the case of the example of FIG. 9, in the line with reference numeral 901, the incident angle is 60 degrees and the contrast is maximized. In the line with reference numeral 902, the incident angle is 70 degrees and the contrast is maximized. In the line with reference numeral 903, the contrast monotonically increases from 0 degrees to 80 degrees of the incident angle. Since the change in brightness indicates a change in the thickness or surface shape of the object 9 in the transport direction 91, in the case of reference numeral 901, the object 9 has a periodic thickness or a change in surface shape with a short periodic length. In the case of reference numeral 902, the object 9 has a longer periodic thickness than in the case of reference numeral 901, and there is a periodic thickness or surface shape change. In the case of reference numeral 903, the periodic object 9 has a longer periodic length than in the case of reference numeral 902. It can be said that there is a long periodic change in thickness or surface shape. The measured values, which are the information shown in FIG. 9, indicate the periodic characteristics of changes in the thickness or surface shape of the object 9 in the transport direction 91, that is, the characteristics of the horizontal streaks on the object 9. More precisely, it shows the characteristics of the variation in light transmission or reflection by the horizontal streaks. The position where the contrast changes from increasing to decreasing is affected by the width of the unit region 64 in the lateral direction 61. That is, the position where the contrast changes from increasing to decreasing depends on the size of the pixels of the imaging unit 24 and the number of pixels in the lateral direction 61 of the unit region 64.

In the measuring device 1, by rotating the object 9, the characteristics of the horizontal streaks can be easily quantified and graphed in a two-dimensional space.

The information obtained as described above can be used for various purposes. For example, in FIG. 9, when the contrast is large on the right side, it can be said that a horizontal streak extending in the width direction 92 and having a long period in the transport direction 91 is generated on the object 9. When the contrast is large on the left side, it can be said that a horizontal streak extending in the width direction 92 and having a short cycle in the transport direction 91 is generated on the object 9. Therefore, when the contrast line is present in the upper left, it can be said that the object 9 has a short-period, conspicuous horizontal streak. As a result, for example, when the incident angle is 70 degrees or less shown by the broken line 911 and the contrast is 0.2 or more shown by the broken line 912, it is determined that the manufactured member does not satisfy the quality standard. Can be done. Since the quality can be evaluated using two parameters, the incident angle of the illumination light and the contrast, for example, when the object 9 is a transparent plate for a touch panel, whether or not the horizontal streaks are inconspicuous at the required viewing angle. It can be evaluated quantitatively with reference to the graph.

Further, the information in FIG. 9 can also be used for adjustment at the time of starting up the manufacturing apparatus. The angle of incidence that maximizes the contrast is determined by the misaligned location of the manufacturing equipment. Misadjustment of the device is, for example, improper adjustment of the position of the gears that mesh with each other, improper temperature of the molten resin, improper speed difference between rolls, improper adjustment of the distance between the die and the roll gap, and the like. .. Horizontal streaks having a peculiar periodicity may appear on the object 9 due to improper adjustment of these molding conditions. Therefore, by acquiring the information shown in FIG. 9, it is possible to quickly grasp the cause of the misalignment of the device. For example, from the characteristics of the horizontal streaks, it is possible to identify which gear the horizontal streaks appear as a gear mark, and it is possible to quickly identify the portion requiring adjustment.

The information in FIG. 9 can also be used for the operator to evaluate the operating ability of the manufacturing apparatus. If there are horizontal streaks that are not misaligned as described above, there is room to further improve the capabilities of the current operator by obtaining information when an expert operates the device when manufacturing with the same material. It is possible to judge whether or not there is. It also helps determine which parts of the device need to be further learned.

The measuring device 1 may perform processing other than the above calculation. By acquiring a plurality of images formed by the light transmitted through the object 9 from a plurality of angles by the image acquisition device 11, the thickness and surface shape of the object 9 in the transport direction 91 are determined based on these images. It is possible to grasp the characteristics of changes and make various judgments.

FIG. 10 is a plan view showing an image acquisition device 11 of the measuring device according to the second embodiment of the present invention. The parts of the measuring device other than the image acquisition device 11 are the same as those in FIG. In FIG. 10, the light source 221 of the lighting unit 22 and the control unit 25 are not shown. In the following description, the components having the same function as that of the first embodiment are designated by the same reference numerals. The image pickup unit 24 of the image acquisition device 11 receives the reflected light from the object 9. The object 9 may or may not be transparent. The surface of the object 9 irradiated with the illumination light is substantially flat.

The structures of the holding portion 21 and the illuminating portion 22 are the same as those in FIGS. 1 and 2. Also in FIG. 10, the direction of the optical axis of the illumination unit 22 is defined as the X direction, the surface of the object 9 is perpendicular to the XY plane, and the transport direction 91 on the object 9 is parallel to the XY plane. be.

The image pickup unit 24 includes a lens 241, a sensor unit 242, and a support unit 243. The lens 241 and the sensor unit 242 are fixed to the support unit 243. Although not shown, as shown by the alternate long and short dash line, a rotation mechanism for rotating the image pickup unit 24 around the axis J1 of the holding unit 21 is further provided. As a result, the image pickup unit 24 moves so that the reflected light is incident on the image pickup unit 24 when the object 9 rotates about the axis J1. The reflected light incident on the image pickup unit 24 is guided to the sensor unit 242 via the lens 241 and the image data is stored in the storage unit of the computer 12 via the control unit 25.

The operation of the measuring device 1 is the same as that of the first embodiment. As shown in FIG. 5, first, the object 9 is arranged so that the angle formed by the normal of the surface of the object 9 and the X direction is the initial first angle (step S11). The parallel light 71 irradiates the object 9 from the X direction (step S12), and the image pickup unit 24 receives the light reflected by the object 9 to acquire an image (step S13). The image data is stored in the storage unit of the computer 12 via the control unit 25.

The control unit 25 rotates the motor 212 to arrange the object 9 at the next rotation position. As a result, the object 9 is arranged so that the angle formed by the normal of the surface of the object 9 and the X direction is the second angle (steps S14 and S15). The image pickup unit 24 also moves so that the reflected light is incident. By executing the image acquisition by the image pickup unit 24 again, the data of the second image is stored in the storage unit of the computer 12 (step S13).

By the control of the control unit 25, the image pickup by the image pickup unit 24 is repeated while changing the second angle formed by the surface of the object 9 and the X direction and the position of the image pickup unit 24 (steps S13 to S15). As a result, a plurality of images are acquired and the data is stored in the computer 12. After that, the irradiation of the object 9 with the light by the lighting unit 22 is stopped (step S16).

The acquired image acquires the brightness of each unit region 64 (more accurately, the corrected brightness) by the same processing as in the first embodiment. The reference brightness used for correcting the brightness is obtained from an image obtained by holding a flat reflector on the holding portion 21. The calculation unit 121 performs the above calculation on a plurality of images. As a result, the change in brightness in the lateral direction 61 of each image, that is, the direction corresponding to the transport direction 91 is acquired (step S17). The change in lightness has periodicity. The calculation unit 121 obtains the contrast, which is the maximum value of the change in brightness in each image, by the same processing as in the first embodiment.

When the image pickup unit 24 receives the reflected light, the change in brightness indicates the change in the shape of the surface of the object 9 in the transport direction 91. By acquiring the contrast from each image, a measured value which is information according to FIG. 9 can be obtained. That is, the relationship between the incident angle and the contrast can be obtained. The relationship between the incident angle and the contrast is displayed on the display 13 (step S18). The measured value indicates the periodic characteristic of the change in the surface shape of the object 9 in the transport direction 91, that is, the characteristic of the horizontal streaks on the object 9. More precisely, it shows the characteristics of the variation in light reflection by the horizontal streaks. Further, in the measuring device, by rotating the object 9, the characteristics of the horizontal streaks can be easily quantified and graphed in a two-dimensional space.

Regarding the information obtained from the second embodiment, which is a reflection type measuring device, as in the first embodiment, the quality of the product, the misadjustment of the device, the judgment of the skill level of the operator, etc. It can be used for various purposes.

The measuring device may perform processing other than the above calculation. By acquiring a plurality of images formed by the light reflected on the object 9 at a plurality of angles, the characteristics of the change in the surface shape of the object 9 in the transport direction 91 can be grasped based on these images. And can make various judgments.

In the above embodiment, a large number of images are acquired, but only two images may be acquired. That is, the iterative process in step S14 may be performed once. Even if only two images are acquired, it is possible to grasp the characteristics of changes in the thickness and surface shape of the object 9 in the transport direction 91. Of course, as described above, it is preferable to repeatedly acquire the image while changing the angle formed by the normal of the surface of the object 9 and the X direction by an angle of 15 degrees or less. This makes it possible to more accurately grasp the characteristics of changes in the thickness or surface shape of the object 9 in the transport direction 91. When the image acquisition time is taken into consideration, the angle to be changed is practically one degree or more.

The image acquisition device 11 and the measurement device 1 according to the above embodiment can be changed in various ways.

In the first embodiment, the image pickup unit 24 acquires the image of the object 9 projected on the screen 23, but as in the second embodiment, the image pickup unit 24 directly receives the light transmitted through the object 9. An image may be acquired by receiving light light. Similarly, in the second embodiment, the light reflected by the object 9 may be guided to the screen, and the image pickup unit 24 may acquire the image projected on the screen. As described above, the image acquisition device 11 may acquire an image derived from the object 9 by various methods.

When the image pickup unit 24 directly receives the light from the object 9, as shown in FIG. 10, when the light receiving surface of the sensor unit 242 is smaller than the cross section of the light flux from the object 9, the light is condensed. Lens 241 is required. However, if the light receiving surface of the sensor unit 242 is larger than the cross section of the light flux from the object 9, the lens 241 can be omitted.

The light emitted to the object 9 is not limited to parallel light. Scattering may occur in the Z direction as long as it is parallel or converges or diverges in the Y direction. Convergence or divergence in the Y direction means that the width of the luminous flux in the Y direction gradually narrows or gradually widens according to the distance from the light source. Of course, the illumination light may be light that converges or diverges in the Z direction. When the illumination light converges or diverges in the Y direction, if the position of the transport direction 91 on the object 9 is different, the distance between the position and the screen 23 or the image pickup unit 24 is different, so that the image is imaged according to the distance. The process of enlarging or reducing each part of the above is performed. These processes can be easily performed from the geometrical positional relationship between the illumination unit 22, the object 9, and the screen 23 or the image pickup unit 24.

In the second embodiment of FIG. 10, the image pickup unit 24 rotates in synchronization with the rotation of the object 9, but the orientation of the object 9 is fixed and the illumination unit 22 and the image pickup unit 24 are centered on the axis J1. You may rotate it. In the examples of FIGS. 2 and 10, the angle of incidence of the illumination light on the object 9 can be easily changed by rotating the object 9 about an axis perpendicular to the XY plane.

In the first embodiment of FIG. 2, the object 9 is not limited to transparency. For example, when the image pickup unit 24 is an infrared camera, the object 9 may be transparent as long as it transmits infrared rays. The object 9 may be transparent to the illumination light.

In the above embodiment, one set of the illumination unit 22 and the image pickup unit 24 are used for multiple times of imaging, but even if the plurality of sets of the illumination unit 22 and the image pickup unit 24 are provided in the measuring device 1. good. In this case, it is possible to simultaneously acquire a plurality of images having different incident angles of the illumination light. By providing a plurality of sets of the lighting unit 22 and the image pickup unit 24 in the measuring device 1, it is possible to provide the measuring device 1 in-line in the manufacturing device for manufacturing the object 9. This enables real-time product inspection and quality evaluation.

The processing in the calculation unit 121 of the computer 12 is not limited to the one described in the above embodiment, and various calculations for obtaining a value indicating the characteristics of the horizontal streaks of the object 9 may be performed. For example, in each of the obtained plurality of images, the average value of the values of the pixels arranged in the vertical direction corresponding to the width direction 92 of the object 9 is obtained, and the change of the average value in the direction corresponding to the transport direction 91 is Fouriered. The characteristics of the horizontal streaks may be obtained by conversion. The characteristics of the horizontal streaks may be grasped by visually confirming a plurality of images by a person. A plurality of images obtained from the light transmitted or reflected through the object 9 at a plurality of angles show the characteristics of the variation in the transmission or reflection of the light due to the horizontal stripes. However, the characteristics of the horizontal streaks can be easily grasped.

The configurations in the above embodiments and the modifications may be appropriately combined as long as they do not conflict with each other.

9 Object 11 Image acquisition device 21 Holding unit 22 Lighting unit 24 Imaging unit 25 Control unit 23 Screen 60 Image 91 Transport direction S11 to S18 Steps

Claims (6)

It is a measuring method for acquiring a measured value indicating the characteristics of the object from a sheet-shaped or plate-shaped object manufactured while being continuously transported in the transport direction.
a) The surface of the object is perpendicular to a predetermined XY plane, the transport direction is parallel to the XY plane, and the normal of the surface of the object is in the X direction. The process of arranging the object so that the angle becomes a predetermined angle, and
b) A step of irradiating the object with light parallel to, converging or diverging in the Y direction from the X direction.
c) A step of acquiring an image by acquiring an image in which light transmitted or reflected by the object is projected on a screen, or by receiving light transmitted or reflected by the object.
d) A step of acquiring the maximum value of the change in brightness of the image in the direction corresponding to the transport direction, and
e) The normal of the surface of the object and the X direction while maintaining a state in which the surface of the object is perpendicular to the XY plane and the transport direction is parallel to the XY plane. By repeating the steps b) to d) while changing the angle between the two, a plurality of images are acquired and the maximum value of the brightness change of each of the plurality of images is acquired.
f) A step of acquiring the relationship between the angle formed by the normal of the surface of the object and the X direction and the maximum value of the change in brightness.
A measurement method characterized by comprising. The measurement method according to claim 1.
A measuring method , characterized in that, in the step e ), the object is rotated about an axis perpendicular to the XY plane. The measuring method according to claim 1 or 2.
In the step e), the measurement method is characterized in that the steps b) to d) are repeated while changing the angle formed by the normal of the surface of the object and the X direction by an angle of 15 degrees or less. .. A measuring device that acquires measured values indicating the characteristics of the object from a sheet-shaped or plate-shaped object manufactured while being continuously conveyed in the transport direction.
While maintaining a state in which the surface of the object is perpendicular to the predetermined XY plane and the transport direction is parallel to the XY plane, the normal and the X direction of the surface of the object A holding unit that holds the object so that the angle formed by the object can be changed relatively.
An illuminating unit that irradiates the object with light parallel to, converging, or diverging in the Y direction from the X direction.
An image pickup unit that acquires an image by acquiring an image in which light transmitted or reflected by the object is projected on a screen, or by receiving light transmitted or reflected by the object.
An arithmetic unit that acquires the maximum value of the change in brightness of the image in the direction corresponding to the transport direction, and
A control unit that controls the image pickup unit and the holding unit,
Equipped with
Under the control of the control unit, a plurality of images are acquired by the imaging unit repeatedly acquiring images while changing the angle formed by the holding unit between the normal of the surface of the object and the X direction.
The calculation unit acquires the maximum value of the brightness change of each of the plurality of images, and the relationship between the angle formed by the normal of the surface of the object and the X direction and the maximum value of the brightness change. A measuring device characterized by acquiring . The measuring device according to claim 4 .
A measuring device in which the holding portion rotates the object around an axis perpendicular to the XY plane. The measuring device according to claim 4 or 5 .
A measurement characterized in that a plurality of images are acquired while changing the angle formed by the normal of the surface of the object and the X direction by an angle of 15 degrees or less by the control of the control unit. Equipment .

Images