JP4411951B2 - Defect detection apparatus and defect detection method for hologram product - Google Patents

Description

  The present invention relates to an apparatus and method for detecting a defect in a hologram product, and more specifically, includes a hologram region formed by laminating a hologram on the reflecting surface side of a reflecting material, and a non-hologram region that is the other region. The present invention relates to an apparatus and a method for detecting the presence / absence of a defect in each of a hologram area and a non-hologram area in a hologram product.

  Usually, transfer holograms form a reflective material by depositing metal on the surface after transferring the diffraction grating pattern to the resin surface, for example by pressing a stamper with a relief diffraction grating recorded on the surface onto the resin surface. Has been manufactured by. Of course, various materials other than resin may be used.

  The holograms manufactured in this way have a wide variety of designs, and the diffraction directions are various and take arbitrary directions. In general, it is possible to reproduce a hologram image by irradiating light at an angle of reference light at the time of hologram recording. In this way, holograms can reproduce images of various patterns depending on the angle at which light is incident. Therefore, by applying them to IC cards or credit cards, they are applied to forgery prevention and security management. Yes. As described above, since the hologram is applied to forgery prevention, security management, and the like, it is required to surely manufacture the hologram.

  A hologram product using such a hologram is rarely produced as a single hologram and is often combined with an arbitrary pattern of a non-hologram. FIG. 12 is a diagram schematically showing a plane of the hologram product. FIG. 13 is a cross-sectional view taken along the line aa shown in FIG.

  That is, the hologram product 60 includes an adhesive and a lower base material layer 62 for maintaining strength, a reflective layer 64 for providing the reflective material 65, a hologram layer 66 for providing the hologram 67, and an upper portion for protecting the hologram. It has a layered structure in which a base material layer 68 is laminated. The structure of the lower base material layer 62 may change depending on the design and usage. For example, it may be a composite layer having a hue specific to the material or composed of a plurality of different materials. A reflective material 65 is provided on a part of the reflective layer 64. Note that the reflective material 65 does not need to be a solid print, and may be an arbitrary pattern designed like the hologram 67. As the reflecting material 65, for example, aluminum is used in order to maintain the diffraction intensity of the hologram. A hologram 67 is provided on a part of the hologram layer 66. The diffraction grating is engraved on the hologram 67, but it cannot be visually seen. As the upper base material layer 68, a material having a high transmittance is used.

  In this specification, a region in which the reflective material 65 is provided in the reflective layer 64 and a hologram 67 is provided in the hologram layer 66 is referred to as a hologram region 72, and the other region is referred to as a non-hologram region 74. A hologram is observed only in the hologram region 72. Even if the hologram 67 is provided in the hologram layer 66, the hologram is not observed unless the reflective material 65 is provided in the reflective layer 64, and the non-visible region 71, which is such a region, belongs to the non-hologram region 74. In addition, the hologram product 60 includes a reflective material region 76 in which the reflective material 65 is provided and a non-reflective material in which the reflective material 65 is not provided from the viewpoint of whether or not the reflective material 65 is provided in the reflective layer 64. The region 77 is classified. Further, a region where the reflective material 64 is provided on the reflective layer 64 but the hologram 67 is not provided on the hologram layer 66 is referred to as a reflective material non-hologram region 75.

  The hologram product 60 configured in this manner uses the hologram 67 having a very complicated diffraction grating pattern on the order of microns, and therefore, its manufacture is not easy, and sufficient attention must be paid in the manufacturing stage. There is.

  For example, if a foreign material such as dust adheres to the stamper and the hologram product 60 is manufactured with the foreign material still attached, the unevenness of the diffraction grating of the hologram 67 is crushed every time the stamper is pressed, and the correct diffraction grating is obtained. A pattern cannot be obtained.

  Alternatively, not only the defect of the hologram 67 itself, but also when there is a defect of the reflecting material 65 or the reflecting layer 64 itself, or a bonding deviation of the hologram 67 with respect to the reflecting layer 64, a correct diffraction grating pattern cannot be obtained similarly. .

Therefore, it is necessary to strictly inspect for defects even after manufacturing. If a defect is found as a result of the inspection, if it is possible to determine whether it is a defect in the hologram region 72 or a defect in the non-hologram region 74, more detailed information regarding the defect is acquired. This is also preferable from the viewpoint of preventing the recurrence of defects.
Japanese Patent Application No. 2003-31134

  A method for automatically inspecting the hologram region 72 of the hologram product 60 is proposed in Patent Document 1 described above. However, there is a case where the non-hologram area 74 is color-printed on the hologram product 60. In this method, it is necessary to consider the following.

  That is, for example, when the lower base material layer 62 has brightness due to color printing, it is necessary to distinguish between the diffracted light of the hologram 67 and the scattered light from the non-hologram region 74. In general, the diffracted light component in the hologram region 72 is sufficiently smaller than the scattered light component in the non-hologram region 74. For this reason, when the luminance is high such that the color of the lower base layer 62 is white, the dynamic range of the imaging system needs to be significantly increased.

  For the above reasons, it is not easy to simultaneously inspect the hologram area 72 and the non-hologram area 74 of the hologram product 60. For this reason, there is a problem that it is necessary to prepare a dedicated inspection apparatus for each inspection object such as the hologram area 72 and the non-hologram area 74.

  The present invention has been made in view of such circumstances, and in a hologram product including a hologram area and a non-hologram area, it is possible to simultaneously detect the presence or absence of defects in each of the hologram area and the non-hologram area. An object of the present invention is to provide a defect detection apparatus and a defect detection method for a hologram product.

  In order to achieve the above object, the present invention takes the following measures.

That is, the invention of claim 1 is an apparatus for detecting a defect in a hologram product comprising a hologram region formed by laminating holograms on the reflecting surface side of a reflecting material and a non-hologram region that is other than the hologram region, An inspection roller, an inspection light source, an imaging unit, a recognition unit, and first and second determination units are provided.

The inspection roller conveys a hologram product that is a subject. The inspection light source is disposed on the inner surface of the cylindrical container, and is a hologram product conveyed by the inspection roller from all directions substantially on the surface side excluding the normal direction to the surface of the hologram product on the reflection surface side of the reflecting material. Irradiate with inspection light. The imaging unit images each light traveling along the normal direction among the light emitted from the hologram product irradiated with the inspection light, and acquires two-dimensional image data. The recognizing means recognizes a reflecting material region corresponding to a region where the reflecting material exists in the two-dimensional image data based on the two-dimensional image data acquired in advance for the hologram product as a reference, and further Of these, the area corresponding to the hologram area is recognized. The first determination means includes two-dimensional image data of an area corresponding to the hologram area recognized by the recognition means, and two-dimensional image data of the hologram product that is the subject among the two-dimensional image data of the hologram product as a reference. Among them, the presence or absence of a defect in the hologram region of the hologram product as the subject is determined by comparing the two-dimensional image data of the region corresponding to the hologram region. The second determination means includes two-dimensional image data corresponding to a non-hologram area, which is an area that has not been recognized as a hologram area by the recognition means, and a hologram that is the subject of the two-dimensional image data of the hologram product as a reference. By comparing the two-dimensional image data of the product with the two-dimensional image data corresponding to the non-hologram area, the presence / absence of a defect in the non-hologram area of the hologram product as the object is determined.
Here, the substantially all directions on the surface side include a range from the minimum angle h _min to the maximum angle h _{max with} respect to the normal direction to the surface of the hologram product conveyed by the inspection roller , and the minimum angle h _min is the inspection angle. Of the light emitted from the hologram product irradiated with the light, it is smaller than the minimum value of the emission angle θ _{0 with} respect to the normal direction , the maximum angle h _max is 90 ° or more, and the height of the inspection light source in the cylinder direction A relationship of H ≧ r · tan (θ ₀ ) is established between H , the cylindrical radius r of the cylindrical container, and the emission angle θ ₀ .

  Therefore, in the hologram product defect detection apparatus according to the first aspect of the present invention, the presence or absence of defects in each of the hologram area and the non-hologram area can be detected simultaneously by taking the above-described means. As a result, it is not necessary to provide a detection device for each of the hologram region and the non-hologram region, and the configuration of the device can be simplified, so that the cost can be reduced. Further, since the defect detection of the hologram area and the non-hologram area can be performed at the same time, the detection time can be shortened, and the detection efficiency can be improved.

  According to a second aspect of the present invention, in the hologram product defect detection apparatus according to the first aspect of the invention, the recognition means has a predetermined threshold value equal to or lower than a predetermined first threshold in the two-dimensional image data acquired in advance for the reference hologram product. An area where light of luminance is imaged is recognized as a reflective material area where a reflective material is present, and an area where light of luminance higher than a predetermined second threshold is imaged among the reflective material areas is a hologram area. Recognize. Further, the first determination means includes the luminance of the light imaged in the region corresponding to the hologram region in the two-dimensional image data of the hologram product as a reference, and the hologram in the two-dimensional image data of the hologram product as the subject. If the difference between the brightness of the light imaged in the region corresponding to the region is equal to or greater than a predetermined third threshold value, it is determined that the hologram region of the hologram product as the subject is defective, and the third If it is less than the threshold, it is determined that there is no defect. Further, the second determination means is configured such that in the two-dimensional image data of the hologram product as a reference, the luminance of the light imaged in the region corresponding to the non-hologram region and the two-dimensional image data of the hologram product that is the subject If the difference between the brightness of the light imaged in the region corresponding to the hologram region is equal to or greater than a predetermined fourth threshold value, it is determined that the non-hologram region of the hologram product as the subject has a defect, If it is less than the threshold value of 4, it is determined that there is no defect.

  Therefore, in the hologram product defect detection apparatus according to the second aspect of the invention, it is possible to improve the defect recognition accuracy in addition to the operational effects achieved by the first aspect of the invention by taking the above-described means. It becomes.

The invention according to claim 3, a hologram region formed by laminating a hologram on the reflective surface of the reflector, an apparatus for detecting defects of the hologram product comprising a non-hologram area that is in other areas, the subject The inspection roller that conveys the hologram product, and the inspection roller that is disposed on the inner surface of the cylindrical container and from substantially all directions on the surface side excluding the normal direction to the surface of the hologram product that is the reflection surface side of the reflector . An inspection light source for irradiating inspection light onto the conveyed hologram product is provided. Furthermore, it has an imaging means for imaging each light traveling along the normal direction out of the light emitted from the hologram product irradiated with the inspection light and acquiring two-dimensional image data. Further, the hologram as the subject is compared by comparing the two-dimensional image data of the hologram product as a reference in which the hologram region and the non-hologram region are identified in advance with the two-dimensional image data of the hologram product as the subject. Judgment means for judging the presence or absence of defects in the hologram area and non-hologram area of the product is provided.
Here, the substantially all directions on the surface side include a range from the minimum angle h _min to the maximum angle h _{max with} respect to the normal direction to the surface of the hologram product conveyed by the inspection roller , and the minimum angle h _min is the inspection angle. Of the light emitted from the hologram product irradiated with the light, it is smaller than the minimum value of the emission angle θ _{0 with} respect to the normal direction , the maximum angle h _max is 90 ° or more, and the height of the inspection light source in the cylinder direction A relationship of H ≧ r · tan (θ ₀ ) is established between H , the cylindrical radius r of the cylindrical container, and the emission angle θ ₀ .

  Therefore, in the hologram product defect detection apparatus according to the third aspect of the present invention, the presence / absence of a defect in each of the hologram area and the non-hologram area can be detected simultaneously by taking the above-described means. As a result, it is not necessary to provide a detection device for each of the hologram region and the non-hologram region, and the configuration of the device can be simplified, so that the cost can be reduced. Further, since the defect detection of the hologram area and the non-hologram area can be performed at the same time, the detection time can be shortened, and the detection efficiency can be improved.

  According to a fourth aspect of the present invention, in the hologram product defect detection device according to any one of the first to third aspects of the present invention, the imaging means is emitted from the hologram product irradiated with the inspection light, along the normal direction. Of each traveling light, the signal intensity due to the light from the reflecting material area corresponding to the area where the reflecting material exists is greater than the signal intensity due to the light from the non-reflecting material area that is an area other than the reflecting material area in the hologram product. Images are taken after amplification at a high amplification factor.

  Therefore, the hologram product defect detection apparatus according to the fourth aspect of the present invention can be applied to a hologram product having a signal intensity greatly different depending on a region by taking the above-described means.

  According to a fifth aspect of the present invention, in the hologram product defect detecting apparatus according to the fourth aspect of the invention, the imaging means includes a non-linear amplifying means that amplifies a signal having a higher intensity with a lower amplification factor, and the non-linear amplifying means The signal intensity by the light from the material region is amplified at a higher amplification factor than the signal intensity by the light from the non-reflective material region.

  Therefore, the hologram product defect detection apparatus according to the fifth aspect of the invention can be applied to a hologram product having a signal intensity greatly different depending on a region by providing the nonlinear amplification means.

The invention of claim 6 is a method of detecting a defect of a hologram product comprising a hologram region formed by laminating holograms on the reflecting surface side of a reflecting material and a non-hologram region that is a region other than the hologram region, The hologram product that is the subject is transported by the inspection roller, and the hologram that is transported by the inspection roller from all directions on the surface side excluding the normal direction to the surface that is the reflective surface of the reflective material of the reference hologram product The product is irradiated with inspection light using an inspection light source disposed on the inner surface of the cylindrical container . Then, among the light emitted from the hologram product as a reference, each light traveling along the normal direction is imaged by an imaging means to obtain two-dimensional image data, and based on the two-dimensional image data, two-dimensional In the image data, a reflective material region corresponding to the region where the reflective material exists is recognized, and further, a region corresponding to the hologram region in the reflective material region is recognized.

  Next, from all directions on the surface side excluding the normal direction to the surface of the hologram product that is the subject, the hologram product is irradiated with inspection light, and among the light emitted from the hologram product that is the subject, Each light traveling along the normal direction is imaged by an imaging means to acquire two-dimensional image data, and by comparing the two-dimensional image data with the reference image data, a hologram area in the two-dimensional image data is obtained. The corresponding part and the part corresponding to the non-hologram area are recognized.

  Furthermore, among the two-dimensional image data of the hologram product as a reference, the two-dimensional image data of the region corresponding to the recognized hologram region and the two-dimensional image data of the hologram product as the subject correspond to the hologram region. The presence / absence of a defect in the hologram region of the hologram product as the subject is determined by comparing the two-dimensional image data of the region.

Similarly, of the two-dimensional image data of the hologram product as a reference, two-dimensional image data corresponding to a non-hologram region that is a region that has not been recognized as a hologram region, and two-dimensional image data of the hologram product that is the subject Among these, by comparing with the two-dimensional image data corresponding to the non-hologram area, the presence / absence of a defect in the non-hologram area of the hologram product as the subject is determined.
Here, the substantially all directions on the surface side include a range from the minimum angle h _min to the maximum angle h _{max with} respect to the normal direction to the surface of the hologram product conveyed by the inspection roller , and the minimum angle h _min is the inspection angle. Of the light emitted from the hologram product irradiated with the light, it is smaller than the minimum value of the emission angle θ _{0 with} respect to the normal direction , the maximum angle h _max is 90 ° or more, and the height of the inspection light source in the cylinder direction A relationship of H ≧ r · tan (θ ₀ ) is established between H , the cylindrical radius r of the cylindrical container, and the emission angle θ ₀ .

  Therefore, in the hologram product defect detection method according to the sixth aspect of the present invention, the presence / absence of defects in each of the hologram region and the non-hologram region can be detected simultaneously by taking the above-described means. As a result, it is not necessary to provide a detection device for each of the hologram region and the non-hologram region, and the configuration of the device can be simplified, so that the cost can be reduced. Further, since the defect detection of the hologram area and the non-hologram area can be performed at the same time, the detection time can be shortened, and the detection efficiency can be improved.

  According to a seventh aspect of the present invention, in the hologram product defect detection method of the sixth aspect of the invention, when a region corresponding to the hologram region is recognized, the two-dimensional image data of the reference hologram product has a predetermined first An area in which light having a luminance less than or equal to a threshold is imaged is recognized as a reflective material area in which a reflective material is present, and among the reflective material areas, an area in which light having a luminance greater than or equal to a predetermined second threshold is imaged Is recognized as a hologram region. Further, when determining whether or not there is a defect in the hologram area, in the two-dimensional image data of the hologram product as a reference, the luminance of the light imaged in the area corresponding to the hologram area and the hologram product that is the subject In the two-dimensional image data, if the difference between the brightness of the light imaged in the region corresponding to the hologram region is equal to or greater than a predetermined third threshold value, a defect is present in the hologram region of the hologram product that is the subject. It is determined that there is a defect, and if it is less than the third threshold, it is determined that there is no defect. Similarly, when determining whether or not there is a defect in the non-hologram area, in the two-dimensional image data of the hologram product as a reference, the luminance of the light imaged in the area corresponding to the non-hologram area, and the subject In the two-dimensional image data of a certain hologram product, when the difference from the brightness of the light imaged in the region corresponding to the non-hologram region is equal to or greater than a predetermined fourth threshold, the non-hologram of the subject hologram product It is determined that there is a defect in the hologram area, and if it is less than the fourth threshold, it is determined that there is no defect.

  Therefore, in the hologram product defect detection apparatus according to the seventh aspect of the invention, by taking the above-described means, it is possible to increase the defect recognition accuracy in addition to the function and effect achieved by the sixth aspect of the invention. It becomes.

The invention of claim 8 is a method of detecting the hologram area formed by laminating a hologram on the reflective surface of the reflector, defects hologram product comprising a non-hologram area that is in other areas, the subject The hologram product is conveyed by an inspection roller, and the hologram product conveyed by the inspection roller is moved from the substantially normal direction to the surface that is the reflection surface side of the reflective material from all directions on the surface side of the cylindrical container. The inspection light source is used to irradiate inspection light on the inner surface, and the light emitted from the hologram product irradiated with the inspection light is imaged by the imaging means to travel along the normal direction. Two-dimensional image data is acquired. Then, by comparing the two-dimensional image data of the reference hologram product in which the hologram region and the non-hologram region are identified in advance with the two-dimensional image data acquired by the imaging unit, the hologram product as the subject The presence / absence of defects in the hologram area and the non-hologram area is determined.
Here, the substantially all directions on the surface side include a range from the minimum angle h _min to the maximum angle h _{max with} respect to the normal direction to the surface of the hologram product conveyed by the inspection roller , and the minimum angle h _min is the inspection angle. Of the light emitted from the hologram product irradiated with the light, it is smaller than the minimum value of the emission angle θ _{0 with} respect to the normal direction , the maximum angle h _max is 90 ° or more, and the height of the inspection light source in the cylinder direction A relationship of H ≧ r · tan (θ ₀ ) is established between H , the cylindrical radius r of the cylindrical container, and the emission angle θ ₀ .

  Therefore, in the hologram product defect detection method according to the eighth aspect of the present invention, the presence or absence of defects in the hologram area and the non-hologram area can be simultaneously detected by taking the above-described means. As a result, it is not necessary to provide a detection device for each of the hologram region and the non-hologram region, and the configuration of the device can be simplified, so that the cost can be reduced. Further, since the defect detection of the hologram area and the non-hologram area can be performed at the same time, the detection time can be shortened, and the detection efficiency can be improved.

  The invention according to claim 9 is the hologram product defect detection method according to any one of claims 6 to 8, wherein the imaging means is emitted from the hologram product irradiated with the inspection light along the normal direction. Of each traveling light, the signal intensity due to the light from the reflecting material area corresponding to the area where the reflecting material exists is greater than the signal intensity due to the light from the non-reflecting material area that is an area other than the reflecting material area in the hologram product. Images are taken after amplification at a high amplification factor.

  Therefore, the hologram product defect detection method according to the ninth aspect of the invention can be applied to a hologram product whose signal intensity varies greatly depending on the region by taking the above-described means.

  According to the defect detection apparatus and the defect detection method of the hologram product of the present invention, it is possible to simultaneously detect the presence or absence of defects in each of the hologram region and the non-hologram region in the hologram product including the hologram region and the non-hologram region. It becomes.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  In addition, the code | symbol in the figure used for description of each following form attaches | subjects and shows the same code | symbol about the same part as FIG. 12 and FIG.

  An embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a functional configuration diagram illustrating an example of a hologram product defect detection apparatus to which a hologram product defect detection method according to an embodiment of the present invention is applied.

  That is, the hologram product defect detection apparatus to which the hologram product defect detection method according to the embodiment is applied is an apparatus for detecting defects on the surface of the thin hologram product 60 that is the subject, and the light irradiation unit 10. And an image data processing unit 12 and a defect display unit 14.

  The light irradiation unit 10 is a cylindrical illumination that includes an inspection roller 11 that continuously conveys a hologram product 60 that is a subject, and a light source that irradiates the product 60 conveyed by the inspection roller 11 with inspection light from the surroundings. And an imaging unit 18 that is provided immediately above the surface of the hologram product 60 and images light generated in the normal direction to the surface from the hologram product 60 irradiated with the inspection light.

  The light source used in the illumination unit 15 may be a light source that is repeatedly lit, such as a fluorescent tube, but a light source that can be dc-lit, such as halogen or xenon, and has sufficient intensity is more preferable. Although not shown, the light source is composed of a light emitting part and a transparent or semi-turbid member that guides it. Further, an illumination light source unit 16 that supplies power or light flux to the light source is provided on the upper side inside the light irradiation unit 10.

By sufficiently taking the height H of the illumination unit 15, the surface of the hologram product 60 can be irradiated with the inspection light h (from the minimum angle inspection light h _min to the maximum angle inspection light h _max ) from substantially all directions. I am doing so.

  As described above, when the inspection light h is irradiated from all directions on the surface side of the hologram product 60, if there is no defect in the hologram 67 in the hologram region 72 of the hologram product 60, each location on the surface of the hologram 67 is obtained. Among the diffracted lights diffracted in step (b), there is always diffracted light k that is diffracted in the direction perpendicular to the surface of the hologram product 60.

  The reason is as follows. That is, as shown in FIG. 2A, in a certain small area on the surface of the hologram 67, when the inspection light h focused from the vertical direction is irradiated on the area, the entire celestial sphere (hemisphere) centered on the area is irradiated. ) Diffracted light (primary) k is always generated in some direction of 21. As shown in FIG. 2B, conversely, when the inspection light h is irradiated onto the region of the hologram 67 from the direction in which the diffracted light k is generated, the diffracted light k is generated in a direction perpendicular to the region. It can also be said. Although the diffracted light has components of ± 1, ± 2,..., ± Nth order diffracted light, it is irrelevant to the diffraction order, so only the first order diffracted light will be described below.

  If this is utilized, the inspection light h is irradiated from the omnidirectional (hemispheric) direction, so that the diffracted light is always perpendicular to the surface of the hologram 67 from a very small area on the hologram 67 having an arbitrary diffraction angle. k can be generated. Here, by arranging the imaging unit 18 in the vertical direction, the diffracted light k generated from all the minute regions is imaged. The imaging unit 18 includes a lens 22, an imaging element 24, and a nonlinear conversion circuit 26.

  The lens 22 is provided between the image sensor 24 and the hologram product 60, and guides only the diffracted light k traveling straight along the normal direction to the image sensor 24. A telecentric lens is suitable as such a lens. Hereinafter, a case where a telecentric lens is used as the lens 22 will be described.

  As shown in FIG. 3A, the telecentric lens is composed of two lenses 22 (#a) and 22 (#b) and a pinhole P, and is irradiated with the inspection light h. This is suitable for capturing an image of the surface of the hologram 67 viewed from directly above. That is, as shown in FIG. 3 (a), the telecentric lens forms an image using only the light traveling straight, so that the light entering obliquely as shown by the symbol b in FIG. 3 (a). Does not image. For this reason, for example, when the cylindrical body 25 is viewed from directly above, as shown in FIG. 3B, an image consisting only of the body portion 25 (#a) and the hollow portion 25 (#b) can be obtained. .

  On the other hand, as shown in FIG. 4A, a general photographic lens that is not a telecentric lens is composed of a set of two lenses 27 (#a) and 27 (#b). As indicated by the symbol c in a), the light entering from an angle is also imaged. For this reason, even when the cylindrical body 25 is viewed from directly above, as shown in FIG. 4B, the inner side surface 25 is interposed between the body portion 25 (#a) and the hollow portion 25 (#b). The image is formed so that (#c) exists.

 The telecentric lens can be either a single-side telecentric lens or a double-sided telecentric lens, but it is desirable that the magnification satisfy the relationship between the size of the image sensor 24 and the imaging field size.

  The image sensor 24 is preferably a line sensor, but an area sensor may be used. Then, the light guided by the lens 22 is imaged, converted from the intensity of the light into an analog electric signal, and this electric signal is output to the non-linear conversion circuit 26.

  As will be described later, since the quality of the hologram 67 is usually evaluated in the visible light region (wavelength λ = 380 to 780 nm), inspection in the visible light region will be described.

  Although it is ideal that there is no blind spot in the irradiation angle range of the inspection light h with respect to the hologram 67, since the imaging unit 18 occupies a predetermined physical space, it is difficult to completely eliminate the blind spot as the physical space. However, by utilizing the various characteristics of the hologram 67, even if the imaging unit 18 is arranged inside the light irradiation unit 10 as shown in FIG. Can be eliminated. The reason is as follows.

  That is, in general, as factors determining the diffracted light characteristics of the hologram 67, the diffraction grating pitch d, the direction of the diffraction grating diffraction direction in the surface direction of the hologram 67, and the incident angle θi and the outgoing angle θo formed with the normal direction of the hologram surface, There is a wavelength λ of the inspection light h.

These have the relationship of the following formula (1).
λ = d (sin θi + sin θo) (1)
Here, in order to simplify the explanation, when θi = 0 (when the inspection light h is irradiated from the normal direction of the hologram 67), the following equation (2) is obtained.
λ = d × sin θo (2)
Here, when the wavelength λ of the inspection light h is visible light, since λ = 380 to 780 nm, the angles that θo can take are as shown in the following equations (3) and (3 ′). In the present embodiment, the light source provided in the illumination unit 15 is bilaterally symmetric, so only a diffraction angle within 90 ° may be targeted.
arcsin (380 / dmax) ≦ θo ≦ arcsin (780 / dmin)
However, when 780 / dmin <1 (3)
arcsin (380 / dmax) ≦ θo ≦ 90 °
However, when 780 / dmin ≧ 1, (3 ')
The diffraction grating pitch d depends on the type of hologram 67, manufacturing conditions, etc., and thus cannot be determined unconditionally, but it is considered to be about 500 nm to 2500 nm. In this case, the emission angle θo, that is, the diffraction range of the inspection light h is expressed by the following equation (4).
10.95 ° ≦ θo ≦ 90 ° (4)
That is, the range where the emission angle θo <10.95 ° is a blind angle, and in this range, the diffracted light k with respect to the hologram 67 does not exist. Therefore, the emission range of the diffracted light k from the hologram 67 is an area indicated by hatching in FIG. 5, and an area not indicated by hatching is the blind spot area J. That is, even if the inspection light h is irradiated from the blind spot area J shown in FIG. 5 toward the hologram 67, the diffracted light k from the hologram 67 does not exist.

  In this embodiment, the imaging unit 18 is arranged in this blind spot area J. This prevents the imaging unit 18 from affecting the imaging of the diffracted light k as described above.

Further, the irradiation angle of the minimum angle inspection light h _min only needs to be smaller than the minimum value of the emission angle θo. In the case of the cylindrical illumination unit 15, the height H satisfying such a condition is defined as r being the cylindrical inner diameter. According to the above equation (4) and the following equation (5),
H ≧ r / tan (θo) (5)
H ≧ 230 mm in the lower limit direction (10.95 ° ≦ θo) (when r = 35 mm). By taking this height H, no blind spots are generated.

  On the other hand, in the upper limit direction (θo ≦ 90 °), since the inspection light h is incident on the hologram 67 from the side, the inspection light h is incident on the central area of the flat hologram product 60. This is often difficult for reasons of device configuration such as being difficult, or workability in the vicinity of the illumination unit 15 and the hologram 67 is deteriorated. Therefore, as illustrated in FIG. 6, the hologram product 60 is supplied to the inspection area 30 by the inspection roller 11 in a convexly curved state when viewed from the illumination unit 15 side.

  By irradiating the inspection light h from the illumination unit 15 in a state where the hologram product 60 is curved by the inspection roller 11 and arranged in the inspection area 30, even a flat hologram 67 is usually placed at any place on the surface. In contrast, the inspection light h can be irradiated from an angle of 90 ° or more.

With the configuration as described above, the irradiation angle range of the inspection light h can cover a range including the upper limit direction inspection light h _max (90 °) from the lower limit direction inspection light h _min (10.95 °).

  By the way, the hologram layer 66 and the reflective layer 64 are made of a material having a high glossiness due to the nature of the substrate. For this reason, the specularly reflected light is almost specularly reflected, and its reflection angle is equal to the incident angle. In the imaging unit 18, since there is no inspection light h in the normal direction with respect to the surface of the hologram product 60, the regular reflection light component is not imaged on the imaging element 24. Therefore, the reflected light from the reflective layer 64 does not enter the image sensor 24.

  Further, when the hologram product 60 is irradiated with the inspection light h, scattered light is generated depending on the material of the lower base material layer 62. For example, the component of the scattered light becomes stronger as the material of the lower base material layer 62 is white and the surface is the diffusion surface, and this component is imaged on the image sensor 24.

  In general, when the lower base material layer 62 is white and has a scattering surface, the luminance from this part is often nearly an order of magnitude higher than the intensity of diffracted light generated by the diffraction grating of the hologram 67. Therefore, when the sensitivity range of the image sensor 24 is adjusted to the scattered light intensity, the entire luminance range can be captured as a matter of course, but the contrast with respect to the presence or absence of diffracted light is relatively lowered. On the contrary, when the sensitivity range is matched with the diffracted light intensity, the scattered light from the lower base material layer 62 is saturated, and when the image pickup device 24 picks up an image, an undesired phenomenon such as halation is caused.

  One proposal for solving this is to increase the dynamic range of the image sensor 24. However, this is not easy to achieve due to circumstances such as time consuming and costly. As an alternative, non-linear processing as shown in FIG. 7 is applied to the electrical signal from the image sensor 24 to emphasize the dark luminance part (the side with the lower input intensity signal) and the bright luminance part (input). The higher intensity signal) is compressed so that two objects with a large luminance difference can be imaged simultaneously.

  That is, the nonlinear conversion circuit 26 has input / output characteristics as shown in FIG. Due to such input / output characteristics, among the electric signals output from the image sensor 24, the signal from the dark luminance part having a low intensity is substantially proportionally amplified, and the signal from the bright luminance part having a high intensity is obtained. Signal processing that does not amplify so much is performed. Then, after performing such signal processing, two-dimensional image data is generated by converting it into a digital signal. Then, the generated two-dimensional image data is output to the image data processing unit 12. Note that an analog electrical signal may be output to the image data processing unit 12, and the image data processing unit 12 may digitally convert the analog electrical signal to generate image data.

  The image data processing unit 12 includes an image capturing unit 32, a subject image acquisition unit 34, a reference image storage unit 36, a recognition unit 38, and a defect determination unit 40.

  The image capturing unit 32 acquires two-dimensional image data that is a digital electrical signal output from the imaging unit 18. When the two-dimensional image data output from the imaging unit 18 is a non-defective product and the reference hologram product 60, the reference two-dimensional image data that is the two-dimensional image data is used as the reference image. Store in the storage unit 36. On the other hand, when the two-dimensional image data output from the imaging unit 18 is that of the hologram product 60 that is the subject, the subject two-dimensional image data that is the two-dimensional image data is used as the subject image acquisition unit. 34. The hologram product defect detection apparatus according to the present embodiment determines the presence or absence of a defect by comparing the subject two-dimensional image data with the reference two-dimensional image data. For this reason, the reference two-dimensional image data must be acquired and stored in the reference image storage unit 36 without fail. Therefore, once the reference two-dimensional image data is stored in the reference image storage unit 36, the two-dimensional image data output from the imaging unit 18 is used for the subject thereafter except when new reference two-dimensional image data is stored. What is necessary is just to output to the subject image acquisition part 34 as two-dimensional image data.

  The reference image storage unit 36 stores the reference two-dimensional image data output from the image capturing unit 32 in a state where it can be provided to the recognition unit 38. On the other hand, the subject image acquisition unit 34 outputs the subject two-dimensional image data output from the image capturing unit 32 to the defect determination unit 40.

  Based on the reference two-dimensional image data from the reference image storage unit 36, the recognition unit 38 recognizes a reflection material region 76 corresponding to a region where the reflection material 65 exists in the two-dimensional image data, and further reflects the reflection material region. The hologram area 72 of 76 is recognized. Further, the non-hologram area 74 is recognized. This recognition method will be specifically described with reference to FIG.

  FIG. 8C is an elevational sectional view along an imaging line of one unit of the hologram product 60 conveyed to the inspection area 30 by the inspection roller 11. Note that one unit means that a plurality of hologram products 60 are normally manufactured continuously on a tape, and thus are one of them. The hologram product 60 includes areas A, B, C, D, and E along the conveyance direction of the inspection roller 11.

  Region A is a non-hologram region 74 in which neither the reflector 65 nor the hologram 67 is provided. At the same time, it is a non-reflecting material region 77. Region B is a hologram region 72 in which both the reflector 65 and the hologram 67 are provided. At the same time, it is also a reflector region 76. The region C is a non-hologram region 75 of the reflecting material in which the reflecting material 65 is provided but the hologram 67 is not provided. At the same time, it is also a reflector region 76 and a non-hologram region 74. The region D is a non-hologram region 74 as with the region A. It is also a non-reflecting material region 77. The region E is a non-reflective material region 77 and a non-visible hologram region 71 because the hologram 67 is provided but the reflective material 65 is not provided.

  In the case of region A, region D, and region E, when the hologram product 60 is irradiated with the inspection light h, the light scattered by the lower base material layer 62 is imaged. As described above, since the scattered light from the lower base material layer 62 is bright, it is captured as a white image as shown in FIG. 8B, and in the high luminance range X as shown in FIG. Belongs.

  On the other hand, in the region B, when the inspection light h is irradiated onto the hologram product 60, the diffracted light from the hologram 67 is imaged. As described above, the intensity of this diffracted light is one order of magnitude smaller than the scattered light from the regions A and D. Therefore, as shown in FIG. 8 (b), the image is captured as a dark image, and as shown in FIG. 8 (a), the diffraction is about one digit smaller than the luminance of the scattered light from the regions A and D. It belongs to the light luminance range Y.

  Furthermore, in the area C, the hologram 67 does not exist and the reflector 65 exists. When the inspection light h is directly applied to the reflecting material 65, the inspection light h is totally reflected on the surface of the reflecting material 65, so that no light is collected by the lens 22. Therefore, as shown in FIG. 8B, the image is picked up as a black image, and as shown in FIG. 8A, in the low luminance range Z, which is a luminance smaller than the luminance of the diffracted light from the region B. Belongs. The thresholds t1 and t2 of the high luminance range X and the diffracted light luminance range Y and the diffracted light luminance range Y and the low luminance range Z are set in advance so that the areas A to E coincide with the luminance ranges to which they belong. Set it up.

  Based on the reference two-dimensional image data obtained by combining image data along a certain imaging line, the recognition unit 38 has a reflective material 65 in an area where light having a luminance equal to or lower than the threshold t1 is captured. The reflection material region 76 is recognized, and the region of the reflection material region 76 in which light having a luminance equal to or higher than the threshold value t <b> 2 is captured is recognized as the hologram region 72, and the recognition result is output to the defect determination unit 40.

  The defect determination unit 40 compares the recognition result from the recognition unit 38 with the two-dimensional image data of the subject from the subject image acquisition unit 34 to thereby detect the hologram region 72 and the non-hologram of the hologram product 60 that is the subject. It is determined whether or not the area 74 has a defect.

  Specifically, the luminance distribution of the reference two-dimensional image data as shown in FIG. 8A is compared with the luminance distribution of the subject two-dimensional image data as shown in FIG. 9A, for example. If the luminance range to which the reference two-dimensional image data in each of the regions A to E recognized by the recognition unit 38 and the luminance range to which the subject two-dimensional image data corresponding to the region belong is different, the region If it is the same, it is determined that there is no defect.

  In the hologram product 60 (#a) shown in FIG. 9C, the diffraction grating is defective at two locations of the hologram 67. That is, there are diffraction grating defects 42 (#a) and 42 (#b). Further, there are also two missing portions in the reflecting material 65, that is, reflecting material missing portions 44 (#a) and 44 (#b). Further, the lower base material layer 62 also has three places, that is, the lower base parts 46 (#a), 46 (#b), and 46 (#c).

  The image of the hologram product 60 (#a) having such a defect looks as shown in FIG. 9B, and the diffraction grating defects 42 (#a) and 42 (#b) and the reflector missing 44 (#a). , 44 (#b) and the region corresponding to the lower base material removal 46 (#b), 46 (#c) are different from those shown in FIG. The lower base material removal 46 (#a) is the same as that shown in FIG. 8B because there is no interaction between the inspection light h and the lower base material layer 62 in any case. Accordingly, the luminance distribution is as shown by the dotted line in FIG. 9A, and is different from the luminance distribution by the reference image data shown by the solid line in FIG. 9A.

  The peak portions N1 to N6 shown in FIG. 9A are the diffraction grating defect 42 (#a), the reflector missing 44 (#a), the diffraction grating defect 42 (#b), and the reflector missing 44 (#b), respectively. The lower base material missing 46 (#b) and the lower base material missing 46 (#c) occurred. Since the luminance in the region B, which is the hologram region 72, is originally in the low luminance range Z, which must be in the diffracted light luminance range Y, it is determined that there is a defect at a position corresponding to the peak portion N1. In this way, in the positions corresponding to the peak portions N1 to N3 of the region B which is the hologram region 72, in the regions A and C to E other than the hologram region 72, the defects are respectively present in the positions corresponding to the peak portions N4 to N6. Judge that there is.

  In the above description, an example is described in which a defect is determined when it belongs to a luminance range different from the luminance range to which the reference image data belongs. However, separately from such a determination method, for the luminance of the reference image data, When the luminance of the subject image data deviates by a predetermined threshold value or more, it may be determined that there is a defect at the corresponding position. In this case, in the recognition unit 38, the threshold value is the same even if different values are used for the hologram region 72 (diffracted light luminance range Y) and the other regions (high luminance range X, low luminance range Z). A value may be used.

  Next, the operation of the hologram product defect detection apparatus to which the hologram product defect detection method according to the embodiment of the present invention configured as described above is applied will be described.

  That is, using the hologram product defect detection apparatus to which the hologram product defect detection method according to the embodiment is applied, the presence / absence of defects in the hologram region 72 and the non-hologram region 74 in the hologram product 60 that is the subject is determined, respectively. In order to do this, first, it is necessary to obtain reference two-dimensional image data which is a non-defective product and is a two-dimensional image data of the hologram product 60 serving as a reference. This operation will be described with reference to the flowchart shown in FIG.

In this case, first, the reference hologram product 60 is placed in the inspection area 30 by the inspection roller 11 (S1). When the hologram product 60 serving as the reference is arranged in the inspection area 30 in this way, next, the inspection light h that is visible light is irradiated from the illumination unit 15 toward the surface side of the hologram product 60 (S2). . In order to diffract the inspection light h on the surface of the hologram 67 and obtain the diffracted light k from the entire area of the hologram 67 in the normal direction, when visible light is used as the inspection light h, The irradiation angle range must be able to cover the range from the lower limit direction inspection light h _min (10.95 °) to the upper limit direction inspection light h _max (90 °).

  On the other hand, since the illumination unit 15 has a sufficient height H, the hologram product 60 is irradiated with the inspection light h from substantially all directions on the surface side. As a result, the diffracted light k traveling in the direction normal to the surface of the hologram product 60 is emitted from the hologram region 72. In addition to the diffracted light k traveling along the normal direction, high-order diffracted light is emitted from the hologram region 72 in various directions. In addition, diffracted light k traveling in the normal direction is also emitted from the non-visible region 71, but this is not visible light and is not detected by the imaging unit 18.

  In the non-hologram area 74, in the reflector non-hologram area 75, since the inspection light h is totally reflected, there is no light traveling along the normal direction. Further, in the non-hologram area 74, there is light traveling along the normal direction among the light scattered by the lower base material layer 62 from areas other than the reflector non-hologram area 75.

  In this way, when the inspection hologram h is irradiated onto the reference hologram product 60, light traveling in various directions is emitted from the hologram product 60 (S3). Among them, the light traveling along the normal direction with respect to the surface of the hologram product 60 is extracted by, for example, the lens 22 using a telecentric lens and guided to the image sensor 24 (S4).

  As described above, the imaging unit 18 is disposed inside the light irradiation unit 10, but is disposed in a region that does not correspond to the irradiation angle range of the inspection light h emitted from the illumination unit 15. Irradiation of the hologram product 60 of h is not hindered.

  The light guided in step S4 is picked up by the image pickup device 24 using a line type sensor or an area type sensor, converted from an intensity of light into an analog electric signal, and then output to the nonlinear conversion circuit 26. . As described above, the intensity of the scattered light from the area other than the reflection area 75 of the non-hologram area 74 in the light guided to the image sensor 24 is large, and the intensity of the diffracted light from the hologram 67 is about an order of magnitude higher than that. small. In order to cope with this, the non-linear conversion circuit 26 has input / output characteristics as shown in FIG. 7, and among the electric signals output from the image sensor 24, the signal for the diffracted light having a low intensity is almost the same. While amplified proportionally, signals from scattered light with high intensity are not so much amplified. As a result, signal processing is performed such that diffracted light having dark luminance is emphasized and scattered light having bright luminance is compressed (S5), and thereafter converted into a digital signal to generate reference two-dimensional image data. (S6). As a result, two objects having a large luminance difference are imaged by the common imaging unit 18 without providing the imaging units for diffracted light and scattered light. The reference two-dimensional image data generated in this way is output from the nonlinear conversion circuit 26 to the image capturing unit 32 of the image data processing unit 12. Note that an analog electrical signal may be output to the image data processing unit 12, and the image data processing unit 12 may digitally convert the analog electrical signal to generate image data.

  The reference two-dimensional image data output to the image capturing unit 32 is output from the image capturing unit 32 to the reference image storage unit 36 and stored therein (S7).

  Next, using the hologram product defect detection apparatus to which the hologram product defect detection method according to the embodiment is applied, a defect in the visible hologram region 72 and other regions in the hologram product 60 that is the subject is detected respectively. Will be described with reference to the flowchart shown in FIG.

  In step S7, when the reference two-dimensional image data is stored in the reference image storage unit 36, preparations for detecting defects in the hologram region 72 and the non-hologram region 74 in the hologram product 60 that is the subject are ready. First, as in step S1, the hologram product 60 as the subject is placed in the inspection area 30 by the inspection roller 11 (S11). Then, in the same manner as in step S2, the inspection light h which is visible light is irradiated from the illumination unit 15 toward the surface side of the hologram product 60 (S12). In this way, when the inspection light h is irradiated onto the hologram product 60 that is the subject, light traveling in various directions is emitted from the hologram product 60 (S13). Of these, the light traveling along the normal direction with respect to the surface of the hologram product 60 is extracted by the lens 22 using, for example, a telecentric lens and guided to the image sensor 24 (S14). Then, similarly to step S5, signal processing is performed such that the diffracted light having dark luminance is enhanced and the scattered light having bright luminance is compressed (S15). Two-dimensional image data is generated (S16).

  As a result, two objects having a large luminance difference are imaged by the common imaging unit 18 without providing the imaging units for diffracted light and scattered light. The subject two-dimensional image data generated in this manner is output from the nonlinear conversion circuit 26 to the image capturing unit 32 of the image data processing unit 12. Note that an analog electrical signal may be output to the image data processing unit 12, and the image data processing unit 12 may digitally convert the analog electrical signal to generate image data. The subject two-dimensional image data output to the image capturing unit 32 is output from the image capturing unit 32 to the subject image acquiring unit 34. When the subject two-dimensional image data is output to the subject image acquisition unit 34 in this way, the subject two-dimensional image data is further output to the defect determination unit 40 (S17). Further, the reference two-dimensional image data is output from the reference image storage unit 36 to the recognition unit 38 (S18).

  Based on the reference two-dimensional image data from the reference image storage unit 36, the recognition unit 38 recognizes a reflection material region 76 corresponding to a region where the reflection material 65 is present in the two-dimensional image data, and further reflects the reflection material. Of the region 76, the hologram region 72 is recognized. Further, the other area is recognized as the non-hologram area 74 (S19). For example, in the case where the hologram product 60 whose vertical section is shown in FIG. 8C is the subject, when the inspection light h is irradiated onto the region A, the region D, and the region E, the lower base material layer 62 The scattered light is imaged. As described above, since the scattered light from the lower base material layer 62 is bright, it is captured as a white image as shown in FIG. 8B, and in the high luminance range X as shown in FIG. Belongs. On the other hand, in the region B, when the inspection light h is irradiated onto the hologram product 60, the diffracted light from the hologram 67 is imaged. As described above, the intensity of this diffracted light is one order of magnitude smaller than the scattered light from the regions A and D. Therefore, as shown in FIG. 8 (b), the image is captured as a dark image, and as shown in FIG. 8 (a), the diffraction is about one digit smaller than the luminance of the scattered light from the regions A and D. It belongs to the light luminance range Y. Furthermore, in the area C, the hologram 67 does not exist and the reflector 65 exists. When the inspection light h is directly applied to the reflecting material 65, the inspection light h is totally reflected on the surface of the reflecting material 65, so that no light is collected by the lens 22. Therefore, as shown in FIG. 8B, the image is picked up as a black image, and as shown in FIG. 8A, in the low luminance range Z, which is a luminance smaller than the luminance of the diffracted light from the region B. Belongs. The thresholds t1 and t2 of the high luminance range X and the diffracted light luminance range Y and the diffracted light luminance range Y and the low luminance range Z are set in advance so that the areas A to E coincide with the luminance ranges to which they belong. It has been established. In the recognition unit 38, based on the reference two-dimensional image data, the region in which light having a luminance equal to or lower than the threshold value t1 is imaged is recognized as the reflective material region 76 where the reflective material 65 is present. Of the material region 76, a region where light having a luminance equal to or higher than the threshold value t <b> 2 is captured is recognized as the hologram region 72. The other area is recognized as a non-hologram area 74. These recognition results are output to the defect determination unit 40.

  In the defect determination unit 40, the recognition result output from the recognition unit 38 in step S19 is compared with the subject two-dimensional image data output from the subject image acquisition unit 34 in step S17. Then, whether or not there is a defect in the hologram area 72 and the non-hologram area 74 of the hologram product 60 that is the subject is determined (S20). That is, if the luminance range to which the reference two-dimensional image data in each of the regions A to E recognized in step S19 belongs and the luminance range to which the subject two-dimensional image data corresponding to the region belongs are different from each other. It is determined that there is a defect, and in the same case, it is determined that there is no defect. For example, in the subject hologram product 60 (#a) shown in FIG. 9C, the diffraction grating is defective at two locations of the hologram 67, and the diffraction grating defects 42 (#a) and 42 (#b) exist. The reflective material 65 also has two reflective material missing portions 44 (#a) and 44 (#b). Further, the lower base material layer 62 also has three lower base material openings 46 (#a), 46 (#b), and 46 (#c). Thus, an image obtained along an imaging line with a defective hologram product 60 (#a) looks as shown in FIG. 9B, and diffraction grating defects 42 (#a), 42 (#b), The regions corresponding to the reflector missing 44 (#a), 44 (#b) and the lower base missing 46 (#b), 46 (#c) are different from those shown in FIG. The lower base member 46 (#a) is the same as that shown in FIG. 8B if there is no interaction between the inspection light h and the lower base layer 62 anyway. Accordingly, the corresponding luminance distribution is as shown by the dotted line in FIG. 9A, and is different from the luminance distribution by the reference image shown by the solid line in FIG. 9A. Since the luminance in the region B, which is the hologram region 72, is originally in the diffracted light luminance range Y but in the low luminance range Z, it is determined that there is a defect at the position corresponding to the peak portion N1. In this way, at the positions corresponding to the peak portions N1 to N3 of the region B which is the hologram region 72, at the positions corresponding to the peak portions N4 to N6 in the regions A and C to E which are the non-hologram regions 74, respectively. It is determined that there is a defect.

  In this way, the determination of the presence / absence of a defect in a certain subject hologram product 60 is completed. If the defect detection determination is subsequently performed for the next subject, the processing from step S11 to step S20 is repeated (S21: Yes). Thereby, the defect detection of the subject hologram product 60 can be continuously performed. When detecting a defect of the hologram product 60 having different specifications, first, the corresponding reference two-dimensional image data is stored in the reference image storage unit 36 by performing the processing shown in the flowchart of FIG. Perform the process shown. Further, even when the hologram product 60 has the same specification, when performing defect determination using different reference two-dimensional image data, first, new reference two-dimensional image data is obtained by performing the processing shown in the flowchart of FIG. Can be dealt with by performing the processing shown in the flowchart of FIG.

  As described above, in the hologram product defect detection apparatus to which the hologram product defect detection method according to the embodiment of the present invention is applied, in each of the hologram region 72 and the non-hologram region 74 due to the above-described action. The presence or absence of defects can be detected simultaneously.

  As a result, it is not necessary to provide a detection device for each of the hologram region 72 and the non-hologram region 74, and the device configuration can be simplified, so that the cost can be reduced.

  Further, since the defect detection of the hologram area 72 and the non-hologram area 74 can be performed at the same time, the detection time can be shortened and the detection efficiency can be improved.

  The best mode for carrying out the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such a configuration. Within the scope of the invented technical idea of the scope of claims, a person skilled in the art can conceive of various changes and modifications. The technical scope of the present invention is also applicable to these changes and modifications. It is understood that it belongs to.

The functional block diagram which shows an example of the hologram product defect detection apparatus to which the defect detection method of the hologram product which concerns on embodiment of this invention is applied. The figure for demonstrating the diffraction direction of the diffracted light by a hologram. The schematic diagram for demonstrating the principle of a telecentric lens. The schematic diagram for demonstrating the principle of a non-telecentric lens. The figure which shows the space which arrange | positions an imaging part in the hologram product defect detection apparatus to which the defect detection method of the hologram product which concerns on embodiment of this invention is applied. Detailed view showing an example of a hologram arranged in the inspection area. The characteristic view which shows an example of the relationship between the input signal strength and output signal strength of a non-linear conversion circuit. The figure which shows an example of luminance distribution along the imaging line with a reference | standard hologram product, the appearance as an image, and an elevation sectional view. The figure which shows an example of luminance distribution along the imaging line with a subject hologram product, the appearance as an image, and an elevation sectional view. 6 is a flowchart showing an operation at the time of acquiring reference two-dimensional image data by the hologram product defect detection apparatus to which the hologram product defect detection method according to the embodiment is applied. The flowchart which shows the operation | movement at the time of the defect detection by the hologram product defect detection apparatus to which the defect detection method of the hologram product which concerns on the embodiment is applied. The top view which shows a general hologram product typically. Sectional drawing along the AA line shown in FIG.

Explanation of symbols

A to E ... area, H ... illumination part height, J ... blind spot area, N1 to N12 ... peak part, P ... pinhole, X ... high luminance range, Y ... diffracted light luminance range, Z ... low luminance range, d ... diffraction grating pitch, h ... inspection light, h _min ... lower limit direction inspection light, h _max ... upper limit direction inspection light, k ... diffraction light, t1, t2 ... threshold, θi ... incident angle, θo ... emission angle, λ ... wavelength DESCRIPTION OF SYMBOLS 10 ... Light irradiation part, 11 ... Inspection roller, 12 ... Image data processing part, 14 ... Defect display part, 15 ... Illumination part, 16 ... Illumination light source part, 18 ... Imaging part, 21 ... Omnisphere, 22, 22 ... Lens, 24 ... Image sensor, 25 ... Cylindrical body, 25 (#a) ... Body, 25 (#b) ... Hollow part, 25 (#c) ... Inner side, 26 ... Nonlinear conversion circuit, 27 ... General lens 30 ... Examination area 32 ... Image capture unit 34 ... Subject image acquisition unit 36 ... Reference image storage unit 38 ... Recognition , 40 ... Defect determination part, 42 ... Diffraction grating defect, 44 ... Reflector missing, 46 ... Lower substrate missing, 48 ... Misaligned part, 60 ... Hologram product, 62 ... Lower substrate layer, 64 ... Reflecting layer, 65 ... Reflective material, 66 ... Hologram layer, 67 ... Hologram, 68 ... Upper base material layer, 71 ... Non-visible region, 72 ... Hologram region, 74 ... Non-hologram region, 75 ... Reflective material non-hologram region, 76 ... Reflective material region , 77 ... Non-reflective material region

Claims (9)

An apparatus for detecting a defect in a hologram product comprising a hologram area formed by laminating holograms on the reflecting surface side of a reflecting material and a non-hologram area that is an area other than the hologram area,
An inspection roller for conveying a hologram product as a subject;
Inspection light is directed to the hologram product conveyed by the inspection roller from all directions substantially on the surface side excluding the normal direction to the surface of the hologram product, which is disposed on the inner surface of the cylindrical container and is on the reflection surface side of the reflector. A light source for inspection light that irradiates
Imaging means for imaging each light traveling along the normal direction out of the light emitted from the hologram product irradiated with the inspection light, and acquiring two-dimensional image data;
Based on the two-dimensional image data acquired in advance for a hologram product as a reference, a reflecting material region corresponding to a region where the reflecting material exists in the two-dimensional image data is recognized, and further, the reflecting material region A recognition means for recognizing an area corresponding to the hologram area,
Of the two-dimensional image data of the hologram product as the reference, the hologram of the two-dimensional image data of the region corresponding to the hologram region recognized by the recognition means and the two-dimensional image data of the hologram product as the subject First determination means for determining the presence / absence of a defect in the hologram region of the hologram product as the object by comparing the two-dimensional image data of the region corresponding to the region;
Of the two-dimensional image data of the reference hologram product, two-dimensional image data corresponding to the non-hologram region, which is a region that has not been recognized as a hologram region by the recognition means, and 2 of the hologram product that is the subject. A second determination means for determining the presence or absence of a defect in the non-hologram region of the hologram product as the subject by comparing the two-dimensional image data corresponding to the non-hologram region in the two-dimensional image data ;
The substantially entire surface side direction includes a range from a minimum angle h _min to a maximum angle h _{max with} respect to a normal direction to the surface of the hologram product conveyed by the inspection roller , and the minimum angle h _min is Of the light emitted from the hologram product irradiated with the inspection light, the output angle θ ₀ is smaller than the minimum value with respect to the normal direction , the maximum angle h _max is 90 ° or more, and the inspection light source A hologram product defect detection device in which a relationship of H ≧ r · tan (θ ₀ ) is established among a height H in the cylinder direction, a cylinder radius r of the cylindrical container, and the emission angle θ ₀ . The hologram product defect detection apparatus according to claim 1,
In the two-dimensional image data acquired in advance for the reference hologram product, the recognizing unit has an area where light having a luminance equal to or lower than a predetermined first threshold is imaged. Recognizing as a reflective material region, further, among the reflective material region, a region in which light having a luminance of a predetermined second threshold or higher is imaged is recognized as the hologram region,
In the two-dimensional image data of the hologram product as the reference, the first determination means includes the luminance of light imaged in a region corresponding to the hologram region and the two-dimensional image data of the hologram product that is the subject. If the difference between the brightness of the light imaged in the area corresponding to the hologram area is equal to or greater than a predetermined third threshold, it is determined that the hologram area of the hologram product as the subject is defective. If it is less than the third threshold, it is determined that there is no defect,
In the two-dimensional image data of the hologram product as the reference, the second determination means includes the luminance of light imaged in a region corresponding to the non-hologram region and the two-dimensional image data of the hologram product as the subject. If the difference between the brightness of the light imaged in the region corresponding to the non-hologram region is equal to or greater than a predetermined fourth threshold value, the non-hologram region of the hologram product as the subject is defective. The hologram product defect detection device is configured to determine that there is no defect when it is less than the fourth threshold value. An apparatus for detecting a defect in a hologram product comprising a hologram area formed by laminating holograms on the reflecting surface side of a reflecting material and a non-hologram area that is an area other than the hologram area,
An inspection roller for conveying a hologram product as a subject;
Inspection light is directed to the hologram product conveyed by the inspection roller from all directions substantially on the surface side excluding the normal direction to the surface of the hologram product, which is disposed on the inner surface of the cylindrical container and is on the reflection surface side of the reflector. A light source for inspection light that irradiates
Imaging means for imaging each light traveling along the normal direction out of the light emitted from the hologram product irradiated with the inspection light, and acquiring two-dimensional image data;
The subject is obtained by comparing the two-dimensional image data of the hologram product as a reference, in which the hologram region and the non-hologram region are identified in advance, and the two-dimensional image data of the hologram product as the subject. Determination means for determining the presence or absence of defects in the hologram area and non-hologram area of the hologram product ,
The substantially entire surface side direction includes a range from a minimum angle h _min to a maximum angle h _{max with} respect to a normal direction to the surface of the hologram product conveyed by the inspection roller , and the minimum angle h _min is Of the light emitted from the hologram product irradiated with the inspection light, the output angle θ ₀ is smaller than the minimum value with respect to the normal direction , the maximum angle h _max is 90 ° or more, and the inspection light source A hologram product defect detection device in which a relationship of H ≧ r · tan (θ ₀ ) is established among a height H in the cylinder direction, a cylinder radius r of the cylindrical container, and the emission angle θ ₀ . In the hologram product defect detection device according to any one of claims 1 to 3,
The image pickup means emits light from the hologram product irradiated with the inspection light, and out of each light traveling along the normal direction, signal intensity due to light from a reflective material region corresponding to a region where the reflective material exists A hologram product defect detection device that picks up an image of the hologram product after amplification at a higher amplification factor than the signal intensity of light from a non-reflective material region other than the reflective material region in the hologram product. In the hologram product defect detection device according to claim 4,
The imaging means includes a non-linear amplifying means that amplifies a signal having a higher intensity at a lower amplification factor. By the non-linear amplifying means, the signal intensity due to the light from the reflecting material region is changed to the light from the non-reflecting material region. A hologram product defect detection apparatus that amplifies at a higher amplification factor than the signal intensity of the signal. A method for detecting a defect in a hologram product comprising a hologram area formed by laminating holograms on the reflecting surface side of a reflecting material and a non-hologram area that is an area other than the hologram area,
The hologram product that is the subject is transported by the inspection roller,
It is arranged on the inner surface of the cylindrical container on the hologram product conveyed by the inspection roller from substantially all directions on the surface side excluding the normal direction to the surface that is the reflecting surface side of the reflecting material of the reflecting material of the reference hologram product. Irradiate the inspection light with the inspection light source ,
Of the light emitted from the hologram product as the reference, each light traveling along the normal direction is imaged by an imaging means to obtain two-dimensional image data,
Based on the two-dimensional image data, a reflecting material region corresponding to a region where the reflecting material exists in the two-dimensional image data is recognized, and further, a region corresponding to the hologram region in the reflecting material region is recognized. ,
Irradiate this hologram product with inspection light from substantially all directions on the surface side excluding the normal direction to the surface of the hologram product that is the subject,
Of the light emitted from the hologram product that is the subject, each light traveling along the normal direction is imaged by an imaging means to obtain two-dimensional image data,
By comparing the two-dimensional image data and the reference image data, a portion corresponding to the hologram region and a portion corresponding to the non-hologram region in the two-dimensional image data are recognized,
Of the two-dimensional image data of the hologram product as a reference, the two-dimensional image data of the region corresponding to the recognized hologram region and the two-dimensional image data of the hologram product as the subject are included in the hologram region. By comparing with the two-dimensional image data of the corresponding region, determine the presence or absence of defects in the hologram region of the hologram product that is the subject,
Of the two-dimensional image data of the hologram product as a reference, two-dimensional image data corresponding to the non-hologram region that is a region not recognized as the hologram region, and two-dimensional image data of the hologram product that is the subject Among these, by comparing with the two-dimensional image data corresponding to the non-hologram area, the presence or absence of defects in the non-hologram area of the hologram product as the subject is determined ,
The substantially entire surface side direction includes a range from a minimum angle h _min to a maximum angle h _{max with} respect to a normal direction to the surface of the hologram product conveyed by the inspection roller , and the minimum angle h _min is Of the light emitted from the hologram product irradiated with the inspection light, the output angle θ ₀ is smaller than the minimum value with respect to the normal direction , the maximum angle h _max is 90 ° or more, and the inspection light source A hologram product defect detection method in which a relationship of H ≧ r · tan (θ ₀ ) is established among the height H in the cylinder direction, the cylinder radius r of the cylindrical container, and the emission angle θ ₀ . The hologram product defect detection method according to claim 6,
When recognizing an area corresponding to the hologram area, in the two-dimensional image data of the reference hologram product, an area where light having a luminance equal to or lower than a predetermined first threshold is captured by the reflector Recognizing as an existing reflective material region, further recognizing the region of the reflective material region where light having a luminance of a predetermined second threshold or more is captured as the hologram region,
When determining whether or not the hologram area has a defect, in the two-dimensional image data of the reference hologram product, the luminance of light imaged in the area corresponding to the hologram area and the subject In the two-dimensional image data of the hologram product, when the difference from the luminance of the light imaged in the region corresponding to the hologram region is equal to or greater than a predetermined third threshold, the hologram of the hologram product as the subject If the area is determined to be defective, and if it is less than the third threshold, it is determined that there is no defect,
When determining whether or not the non-hologram area has a defect, in the two-dimensional image data of the reference hologram product, the luminance of light imaged in the area corresponding to the non-hologram area, and the subject In the two-dimensional image data of the hologram product, the hologram that is the subject when the difference from the luminance of the light imaged in the region corresponding to the non-hologram region is equal to or greater than a predetermined fourth threshold value A hologram product defect detection method in which it is determined that there is a defect in a non-hologram area of a product, and if it is less than the fourth threshold value, it is determined that there is no defect. A method for detecting a defect in a hologram product comprising a hologram area formed by laminating holograms on the reflecting surface side of a reflecting material and a non-hologram area that is an area other than the hologram area,
The hologram product that is the subject is transported by the inspection roller,
A light source for inspection disposed on the inner surface of the cylindrical container from all directions substantially on the surface side excluding the normal direction to the surface on the reflecting surface side of the reflecting material with respect to the hologram product conveyed by the inspection roller Irradiate the inspection light with
Of the light emitted from the hologram product irradiated with the inspection light, each light traveling along the normal direction is imaged by an imaging means to obtain two-dimensional image data,
The object is obtained by comparing the two-dimensional image data of the hologram product as a reference in which the hologram area and the non-hologram area are identified in advance with the two-dimensional image data acquired by the imaging unit. Determine the presence or absence of defects in the hologram area and non-hologram area of the hologram product ,
The substantially entire surface side direction includes a range from a minimum angle h _min to a maximum angle h _{max with} respect to a normal direction to the surface of the hologram product conveyed by the inspection roller , and the minimum angle h _min is Of the light emitted from the hologram product irradiated with the inspection light, the output angle θ ₀ is smaller than the minimum value with respect to the normal direction , the maximum angle h _max is 90 ° or more, and the inspection light source A hologram product defect detection method in which a relationship of H ≧ r · tan (θ ₀ ) is established among the height H in the cylinder direction, the cylinder radius r of the cylindrical container, and the emission angle θ ₀ . In the hologram product defect detection method according to any one of claims 6 to 8,
The image pickup means emits light from the hologram product irradiated with the inspection light, and out of each light traveling along the normal direction, signal intensity due to light from a reflective material region corresponding to a region where the reflective material exists A hologram product defect detection method in which image is picked up after amplification at a higher amplification factor than the signal intensity of light from a non-reflective material region other than the reflective material region in the hologram product.

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