JP2013109129A - Display body for forgery prevention, affixation label thereof, transfer foil and authenticity determination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a latent image formation body which makes it difficult to forge a latent image using polarization technology.SOLUTION: An angle formed between a third slow axis of a third region or a third polarized latent image part and a first straight line is mutually equal to an angle formed between a fourth slow axis of a fourth region or a fourth polarized latent image part or an axis orthogonally intersecting the fourth slow axis and the first straight line, with respect to the first straight line bisecting an angle formed between a first slow axis of a first region or a first polarized latent image part and a second slow axis of a second region or a second polarized latent image part, and an angle formed between the second slow axis of the second region or the second polarized latent image part and a second straight line is mutually equal to an angle formed between the third slow axis of the third region or the third polarized latent image part or an axis orthogonally intersecting the third slow axis and the second straight line, with respect to the second straight line bisecting an angle formed between the first slow axis of the first region or the first polarized latent image part and the first slow axis of the fourth region or the fourth polarized latent image part.

Description

  The present invention relates to an anti-counterfeit medium using a latent image for the purpose of displaying a hidden character or a hidden pattern for performing forgery prevention and authenticity determination of an article by using a filter.

  Conventionally, securities such as banknotes, gift certificates, passports, and authentication media have been pasted with a medium that is difficult to forge as a countermeasure against forgery. In this case, authenticity determination is performed by visual determination (overt function) or determination using a verifier (covert function).

  However, an anti-counterfeit medium that can be visually determined for authenticity is easily forged. Therefore, in recent years, a latent image technique using a polarization technique has been proposed, and in many cases, a latent image appears by overlapping a polarizing film and authenticity is determined.

  However, in this case, a dedicated verifier such as a polarizing film is required for authenticating the latent image device. Normally, a retailer or a service provider can prepare a verifier for authenticity determination and perform authenticity determination on the assumption of a nearby prefecture or ticket received from a consumer. However, it is unlikely that a general consumer has obtained a verifier in advance assuming these situations, and authentication cannot be made.

  Therefore, in order to solve this problem, Patent Document 1 proposes a display body that can visualize a plurality of latent images recorded so as to overlap each other with an excellent contrast ratio. The above prior art patents are shown below.

JP 2009-258151

  However, even a latent image forming body in which a latent image is formed by using a polarization technique may be forged with the passage of time or technological advancement, which is a problem.

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to devise the image itself, such as making a latent image using polarization technology into a complex image instead of a simple image. It is an object of the present invention to provide a latent image forming body that is hardened and difficult to counterfeit.

  According to the first aspect of the present invention, there is provided a retardation layer that includes first to fourth regions that are adjacent to each other in the in-plane direction and have different slow axis directions in the in-plane direction. Any two or more regions have a polarization latent image portion and a polarization background portion, the polarization latent image portion is composed of halftone dots, and has a halftone dot background portion and a halftone dot latent image portion, The halftone dot constituting the halftone dot latent image portion and the halftone dot constituting the halftone dot background portion have a region characterized in that at least one of halftone dot angle, pitch, and halftone dot phase is different. , With respect to the first straight line that bisects the angle formed by the first slow axis of the first region or the first polarization latent image portion and the second slow axis of the second region or the second polarization latent image portion. An angle formed between the third slow axis of the third region or the third polarization latent image portion and the first straight line, and a fourth delay time of the fourth region or the fourth polarization latent image portion. An angle formed by an axis or an axis perpendicular thereto and the first straight line is equal to each other, and the first slow axis of the first region or first polarization latent image portion and the fourth region or fourth polarization latent image portion. An angle formed between the second straight line of the second region or the second polarization latent image portion and the second straight line with respect to a second straight line that bisects the angle formed by the first slow axis of Provided is a display body characterized in that an angle formed between the third slow axis of the third region or the third polarization latent image portion or an axis perpendicular thereto and the second straight line is equal to each other.

  According to a second aspect of the present invention, there is provided a retardation layer including first to fourth regions that are adjacent to each other in an in-plane direction and have different slow axis directions in the in-plane direction. Any two or more regions have a polarization latent image portion and a polarization background portion, and the polarization latent image portion is composed of a line and has a line background portion and a line latent image portion, There is a region characterized in that at least one of the line angle, the pitch, and the line phase is different between the line constituting the line latent image part and the line constituting the line background part. , With respect to the first straight line that bisects the angle formed by the first slow axis of the first region or the first polarization latent image portion and the second slow axis of the second region or the second polarization latent image portion. An angle formed between the third slow axis of the third region or the third polarization latent image portion and the first straight line, and a fourth delay time of the fourth region or the fourth polarization latent image portion. An angle formed by an axis or an axis perpendicular thereto and the first straight line is equal to each other, and the first slow axis of the first region or first polarization latent image portion and the fourth region or fourth polarization latent image portion. An angle formed between the second straight line of the second region or the second polarization latent image portion and the second straight line with respect to a second straight line that bisects the angle formed by the first slow axis of Provided is a display body characterized in that an angle formed between the third slow axis of the third region or the third polarization latent image portion or an axis perpendicular thereto and the second straight line is equal to each other.

According to the third aspect of the present invention, in the in-plane direction of the retardation layer, an angle formed by the first slow axis with respect to a third straight line parallel to the main surface of the retardation layer is a first angle θ. ₁ , the angle formed by the second slow axis is the second angle θ ₂ , the angle formed by the third slow axis is the third angle θ _3, and the angle formed by the fourth slow axis is the fourth angle When the angle θ ₄ is set, the first angle θ ₁ , the second angle θ ₂ , the third angle θ ₃ , the fourth angle θ _4, and the integers L, M, and N are expressed by the relation θ ₂ = θ ₁ + 22.5 ° + 90 ° × L,
θ ₃ = θ ₁ + 45 ° + 90 ° × M and θ ₄ = θ ₁ + 67.5 ° + 90 ° × N
The display body according to claim 1 is provided.

  According to a fourth aspect of the present invention, there is provided the display body according to any one of claims 1 to 3, further comprising a reflective layer facing the retardation layer.

  According to a fifth aspect of the present invention, there is provided the display body according to any one of claims 1 to 3, further comprising a polarizing layer facing the retardation layer.

  According to a sixth aspect of the present invention, there is provided the display body according to claim 5, further comprising an absorption layer facing the polarizing layer.

  According to a seventh aspect of the present invention, there is provided an adhesive label comprising the display body according to any one of claims 1 to 6 and an adhesive layer provided on the display body. .

  According to an eighth aspect of the present invention, there is provided a transfer foil comprising the display body according to any one of claims 1 to 6 and a support layer that releasably supports the display body. provide.

  According to a ninth aspect of the present invention, a display is characterized in that a polarizing sheet is superimposed on the display body according to any one of claims 1 to 8, and authenticity is determined based on the presence or absence of the appearance of a polarization latent image. A method for determining the authenticity of a body is provided.

  According to the tenth aspect of the present invention, a visualization sheet formed by forming a visualization pattern consisting of halftone dots or line patterns is further overlapped to determine whether a halftone dot image or a line latent image appears. The authenticity determination method for a display body according to claim 9, wherein the authenticity determination is performed.

  According to an eleventh aspect of the present invention, a verification device is superimposed on the display body according to any one of claims 1 to 9 to check whether a polarization latent image and a halftone dot latent image or a line latent image appear. There is provided a method for determining authenticity of a display body, characterized in that authenticity determination is performed.

  According to the present invention, a plurality of latent images recorded so as to overlap each other can be visualized with an excellent contrast ratio, and the visualized polarized latent image portion includes a halftone dot latent image portion and a halftone dot. Since it has a background part, a line latent image part, and a line background part, a halftone dot latent image or a line latent image is visualized by overlaying a visualization sheet on which a visualization pattern is formed. Further, it is possible to realize a display body that is difficult to forge and is difficult to notice all the latent images applied.

It is sectional drawing of the display body which concerns on embodiment of this invention. FIG. 6 is a cross-sectional view of a display body according to an embodiment of the invention corresponding to claim 4. FIG. 6 is a cross-sectional view of a display body according to an embodiment of the invention corresponding to claim 5. It is a top view which shows schematically the display body shown in FIG. It is a top view which shows roughly the latent image currently recorded on the display body shown in FIG. It is a top view which shows roughly the latent image currently recorded on the display body shown in FIG. FIG. 5 is an enlarged schematic diagram illustrating an example of an embodiment of a polarization latent image portion of the latent image shown in FIG. The image part is shown. It is a figure for demonstrating the angle of the halftone dot used by this invention, a pitch, and a phase. It is a top view which shows the image displayed when a display body is pinched | interposed between a pair of polarizing filters and this is observed. It is a top view which shows the image displayed when a display body is pinched | interposed between a pair of polarizing filters and this is observed. It is a top view which shows the image displayed when a display body is pinched | interposed between a pair of polarizing filters and this is observed. It is a top view which shows the image displayed when a display body is pinched | interposed between a pair of polarizing filters and this is observed. It is sectional drawing of the verification filter in this invention. 12 is an example of a latent image when a display body is verified using the verification filter illustrated in FIG. 11. It is sectional drawing of the verification filter in this invention. It is an example of a latent image when a display body is verified using the verification filter shown in FIG. It is sectional drawing of the verification filter of an example in this invention. FIG. 16 is an example of a latent image when the display body is verified using the verification filter illustrated in FIG. 15. FIG. (A)-(d) is a figure which shows schematically an example of the mask used for this invention.

  Embodiments of a forgery prevention medium and a method of manufacturing the forgery prevention medium according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view of a display body according to an embodiment of the present invention. A display body 10 shown in FIG. 1 includes a retardation layer 11 laminated on a support 12. A display body 10 according to another embodiment shown in FIG. 2 includes a reflective layer 13 and a retardation layer 11 that are sequentially stacked on a support 12. A display body 10 according to still another embodiment shown in FIG. 3 includes a polarizing layer 14 and a retardation layer 11 that are sequentially stacked on a support 12. On these display bodies 10, at least two images, that is, the first image P1 and the second image P2 are recorded as latent images.

  As shown in FIG. 4, the retardation layer 11 includes at least four regions A1 to A4 that are adjacent to each other in the in-plane direction. Here, the first area A1 is an area corresponding to a portion of the second image P2 shown in FIG. 6 that does not overlap with the first image P1 shown in FIG. The second area A2 is an area corresponding to a portion where neither the first image P1 nor the second image P2 is recorded. The third area A3 is an area corresponding to a portion of the first image P1 that does not overlap with the second image P2. The fourth area A4 is an area corresponding to a portion where the first image P1 and the second image P2 overlap.

  Although details will be described later, the regions A1 to A4 may have a polarization latent image portion and a polarization background portion as shown in FIG. Further, the polarization latent image portion in the present invention may be composed of fine halftone dots or lines.

  In the regions A1 to A4, the directions of the slow axes in the in-plane direction are different from each other. In this aspect, the angle formed between the third slow axis and the first straight line L1 with respect to the first straight line L1 that bisects the angle formed between the first slow axis and the second slow axis, The angle formed by the slow axis or an axis perpendicular thereto and the first straight line L1 is equal to each other. In addition, with respect to the second straight line L2 that bisects the angle formed by the first slow axis and the fourth slow axis, the angle formed by the second slow axis and the second straight line L2, and the third slow phase The angles formed by the axis or the axis orthogonal thereto and the second straight line L2 are equal to each other.

  Here, “equal” for two angles includes not only the case where they are exactly equal, but also the case where both have a relationship that brings about an optical effect that can be identified with human vision. And For example, the two angles need only coincide within an error range of about -5 ° to about 5 °.

  The retardation value of the retardation layer 11 is preferably about a half wavelength with respect to a predetermined design wavelength. The design wavelength is, for example, a wavelength that can be recognized or detected with the highest sensitivity by an observer or a reader. For example, when the display body is observed with the naked eye, a wavelength corresponding to green light having the highest visibility among visible light may be set as the design wavelength. Alternatively, in order to make it difficult to recognize the existence of the latent image, a wavelength with lower visibility may be set as the design wavelength.

  When the retardation value of the retardation layer 11 is about ½ wavelength, when linearly polarized light is incident on the retardation layer, the polarization axis of the linearly polarized light is inverted with respect to the slow axis of the retardation layer. That is, if the angle between the polarization axis of the incident light and the slow axis of the retardation layer is θ, the angle between the polarization axis of the incident light and the polarization axis of the transmitted light is 2θ.

At this time, the case where the display body 10 is observed under parallel Nicols is considered. Here, assuming that the intensity of incident light of the retardation layer is 100 and using the theoretical limit transmittance of 50% of the polarizing filter as an analyzer, the transmittance T of the display body 10 is given by the following equation.

  As described above, in this embodiment, the regions A1 to A4 included in the retardation layer have different slow axis directions in the in-plane direction. Therefore, when linearly polarized light is incident on the retardation layer and observed through the polarizing filter, the transmittances of the regions A1 to A4 can be different from each other according to the above equation. That is, a visible image can be displayed on the display body based on the difference in transmittance between the regions A1 to A4. In addition, when the display body is observed without passing through the polarizing filter, a visible image is not displayed on the display body.

  The image displayed by the display body changes as described below, for example, by rotating the direction of the polarization axis of the polarizing filter in the in-plane direction.

  The angle that the first slow axis makes with the X axis is the first angle θ1, the angle that the second slow axis makes with the X axis is the second angle θ2, and the angle that the third slow axis makes with the X axis is the third angle. The angle θ3 is assumed, and the angle formed by the fourth slow axis and the X axis is the fourth angle θ4.

Here, as an example, the angles θ1 to θ4 are expressed by the relational expression θ2 = θ1 + 22.5 ° + 90 ° × L,
θ3 = θ1 + 45 ° + 90 ° × M and θ4 = θ1 + 67.5 ° + 90 ° × N
Is satisfied. Note that L, M, and N are arbitrary integers.

  In the following, in the above equation, when θ1 = 0 °, L = 0, M = −1 and N = 0, that is, θ1 = 0 °, θ2 = 22.5 °, θ3 = −45 ° and θ4 = A case where the angle is 67.5 ° will be described as an example.

  Hereinafter, an angle formed between the polarization axis of a pair of polarizing filters arranged in a parallel Nicol state and the X axis, that is, an angle formed between the polarization axis of linearly polarized light to be incident and output and the X axis is defined as θP. The transmittances in the regions A1 to A4 are T1 to T4, respectively.

  First, consider the case of θP = 11.25 °. At this time, the polarization axis of the polarizing filter is parallel to the bisector of the angle between the first slow axis (θ1 = 0 °) and the second slow axis (θ2 = 22.5 °). The angle formed between the polarization axis of the polarizing filter and the third slow axis (θ3 = −45 °) is the angle formed between the polarization axis of the polarizing filter and the fourth slow axis (θ4 = 67.5 °). equal.

  In this case, the angle formed by the polarization axis of the polarizing filter and the first slow axis is | θP−θ1 | = 11.25 °. The angle formed by the polarization axis of the polarizing filter and the second slow axis is | θP−θ2 | = 11.25 °. Therefore, the transmittance in the first region A1 and the second region A2 is T1 = T2 = 47.2% from the above equation.

  On the other hand, the angle formed by the polarization axis of the polarizing filter and the third slow axis is | θP−θ3 | = 56.25 °. The angle formed by the polarization axis of the polarizing filter and the fourth slow axis is | θP−θ4 | = 56.25 °. Therefore, the transmittance in the third region A3 and the fourth region A4 is T3 = T4 = 7.3%.

  Therefore, in the transmissive display, the regions A1 and A2 are observed as negative images, and the regions A3 and A4 are observed as positive images. That is, the display body 10 displays the first image P1 as a positive image as shown in FIG.

  Next, consider the case of θP = 33.75 °. At this time, the polarization axis of the polarizing filter is parallel to the bisector of the angle between the first slow axis (θ1 = 0 °) and the fourth slow axis (θ4 = 67.5 °). The angle formed between the polarization axis of the polarizing filter and the second slow axis (θ2 = 22.5 °) is the axis orthogonal to the polarizing axis of the polarizing filter and the third slow axis (θ3 + 90 ° = 45 °). Is equal to the angle formed by

  In this case, the angle formed by the polarization axis of the polarizing filter and the first slow axis is | θP−θ1 | = 33.75 °. The angle formed by the polarization axis of the polarizing filter and the fourth slow axis is | θP−θ4 | = 33.75 °. Therefore, the transmittance in the first area A1 and the fourth area A4 is T1 = T4 = 7.3%.

  On the other hand, the angle formed by the polarization axis of the polarizing filter and the second slow axis is | θP−θ2 | = 11.25 °. The angle formed by the polarization axis of the polarizing filter and the third slow axis is | θP−θ3 | = 78.75 °. Therefore, the transmittance in the second region A2 and the third region A3 is T2 = T3 = 47.2%.

  Therefore, in the transmissive display, the regions A1 and A4 are observed as positive images, and the regions A2 and A3 are observed as negative images. That is, the display body 10 displays the second image P2 as a positive image as shown in FIG.

  Next, consider the case of θP = 56.25 °. In this case, the angle formed between the polarization axis of the polarizing filter and the first slow axis is | θP−θ1 | = 56.25 °. The angle formed by the polarization axis of the polarizing filter and the second slow axis is | θP−θ2 | = 33.75 °. Therefore, the transmittance in the first region A1 and the second region A2 is T1 = T2 = 7.3%.

  On the other hand, the angle formed by the polarization axis of the polarizing filter and the third slow axis is | θP−θ3 | = 78.75 °. The angle formed by the polarization axis of the polarizing filter and the fourth slow axis is | θP−θ4 | = 11.25 °. Therefore, the transmittance in the third region A3 and the fourth region A4 is T3 = T4 = 47.2%.

  Therefore, in the transmissive display, the regions A1 and A2 are observed as positive images, and the regions A3 and A4 are observed as negative images. That is, the display body 10 displays the first image P1 as a negative image as shown in FIG.

  Finally, consider the case of θP = 78.75 °. In this case, the angle formed by the polarization axis of the polarizing filter and the first slow axis is | θP−θ1 | = 78.75 °. The angle formed by the polarization axis of the polarizing filter and the fourth slow axis is | θP−θ4 | = 11.25 °. Therefore, the transmittance in the first region A1 and the fourth region A4 is T1 = T4 = 47.2%.

  On the other hand, the angle formed by the polarization axis of the polarizing filter and the second slow axis is | θP−θ2 | = 56.25 °. The angle formed by the polarization axis of the polarizing filter and the third slow axis is | θP−θ3 | = 56.25 °. Therefore, the transmittance in the second region A2 and the third region A3 is T2 = T3 = 7.3%.

  Therefore, in the transmissive display, the regions A1 and A4 are observed as positive images, and the regions A2 and A3 are observed as negative images. That is, the display body 10 displays the second image P2 as a negative image as shown in FIG.

  Thus, the display body changes the angle θP of the polarization axis of the polarizing filter used for observation, thereby changing the positive image of the first image P1, the positive image of the second image P2, the negative image of the first image P1, and the first image P1. A negative image of two images P2 can be displayed.

  Further, as shown in FIG. 7, the two or three regions A1 to A4 have a polarization latent image portion and a polarization background portion, and the polarization latent image portion is composed of halftone dots or lines. And it is preferable to have a halftone dot or line background part and a halftone dot or line latent image part.

  In addition, as a combination of areas where the image is composed of halftone dots or lines, the combination of the area A1 and the area A4 constituting the second image P2 or the area A3 constituting the first image P1. And the region A4 or a combination of the region A1, the region A3, and the region A4 constituting the first image P1 and the second image P2.

  A halftone dot or a line forming a halftone dot or a line latent image part and a halftone dot or a line forming a halftone dot or a line background part are the size of the dot, the thickness of the line, the angle, Any one or more of pitch and phase are different. Note that the halftone dots or lines forming the polarization latent image portion are fine dots that do not hinder the design, so even if they are visualized as a polarization latent image, they are visually It cannot be confirmed as a dot or line pattern.

  Examples of the shape of the halftone dot include a square dot shape, a round dot shape, a halftone dot shape, a lattice dot shape, or a dot shape formed by a combination thereof.

  Here, the angle, pitch, and phase will be described taking a halftone dot as an example. The angle of halftone dots in the present invention indicates φ in FIG. 8A and represents the inclination of halftone dots that are regularly arranged. The pitch of halftone dots refers to D in FIG. 8A and represents the distance from one halftone dot to the adjacent nearest halftone dot. Further, the ratio between the halftone dot portion and the non-halftone dot portion within the pitch D is called a halftone dot ratio.

  On the other hand, the phase of halftone dots refers to k in FIG. 8B and represents the period of regularly arranged halftone dots. In FIG. 8B, the halftone dots A and B show a state in which the phases are shifted by g.

  The size of the halftone dots and the thickness of the lines are too small or too large, and it is difficult to visually recognize the halftone dot latent images when the visualization sheets are overlaid. Therefore, the range of 10 to 1000 μm, preferably It is desirable to set to 10-500 micrometers. Further, the halftone dot ratio (= halftone dot portion / (halftone dot portion + non-halftone dot portion)) and the line ratio (= 10,000 line portions / (manual line portion + non-halftone dot portion)) may be arbitrarily set. Although it is good, in the range of 1/10 to 9/10, it is preferable to set to 1/3 to 2/3. More preferably, the ratio is 1/2. Therefore, the pitch is preferably set in the range of 20 to 2000 μm, preferably 20 to 1000 μm.

  In order to visualize the halftone dot or line latent image by overlapping and rotating the visualization sheet, the halftone dot size is divided between the halftone dot or line background part and the halftone dot or line latent image part. In addition, halftone dots or line patterns that differ in at least one of the thickness, angle, pitch, and phase of the line may be used. However, if they are too close to each other, it will be difficult to see halftone dots or line latent images.

  FIG. 7 shows a polarization latent image portion composed of halftone dots. However, in FIG. 7, the halftone dots are increased and the pitch is increased for the sake of explanation. FIG. 7A shows a polarization latent image portion in which a halftone dot latent image portion and a halftone dot background portion are combined. FIG. 7B shows only the halftone dot background portion, and FIG. It is a figure which cuts out and shows only a latent-image part.

  In the polarization latent image portion shown in FIG. 7, the halftone dots forming the halftone dot latent image portion and the halftone dot background portion are provided at the same pitch and the same halftone dot ratio and at different angles. The halftone dot angles of the halftone dot latent image portion and the halftone dot background portion are 0 ° and 30 ° with respect to the X axis. Therefore, when a visualization sheet is used, a negative image of a halftone dot latent image appears in the 0 ° direction, and a positive image of a halftone dot latent image appears in the 30 ° direction.

  Next, for example, the second image P2, that is, the area A1 and the area A4 are composed of a polarization latent image portion and a polarization background portion, and the polarization latent image portion is composed of halftone dots having a halftone angle difference of 30 ° as described above. The case will be described.

  As described above, the display body 10 according to the present invention has a polarizing filter on the display body 10 and the angles with respect to the X axis are θP = 11.25 °, 33.75 °, 56.25 °, 78.75 °. When the order is changed, the positive image of the first image P1, the positive image of the polarization latent image portion of the second image P2, the negative image of the first image P1, and the negative image of the polarization latent image portion of the second image P2 are sequentially arranged. Appear.

  Further, when the polarizing filter angle is fixed at θP = 33.75 °, and the polarization latent image portion of the second image P2 is observed as a positive image, and further using a visualization sheet, the 0 ° direction Thus, a negative image of a halftone dot latent image can be visualized in a 30 ° direction and a positive image of a halftone dot latent image can be visualized.

  As shown in FIG. 13, when a verification filter is produced by combining a polarizing filter 22 having an angle with the X axis of θP = 33.75 ° and a visualization sheet 21 having an angle with the X axis of 30 °, An image that could not be observed with the filter alone can be visualized as shown in FIG.

  Further, as shown in FIG. 15, the verification filter 23 whose angle between the X axis and the transmission axis of the polarizing filter is 11.25 °, and the polarization whose angle between the X axis and the transmission axis of the polarizing filter is 33.75 °. If a verification machine in which the filter 22 is integrated is used, the positive image of the first image P1 and the positive image of the second image P2 can be observed simultaneously as shown in FIG.

  Further, as shown in FIG. 17, the angle between the X axis and the transmission axis of the polarizing filter is 11.25 °, and the angle between the X axis and the transmission axis of the polarizing filter is 33.75 °. When a verification machine in which a verification filter Q2 in which a visualization sheet tilted by 30 ° is combined with a polarizing filter is used, a positive image of the first image P1 and a halftone dot latent image of the second image P2 as shown in FIG. Positive images can be observed simultaneously, and a halftone dot latent image that cannot be obtained by using only a polarizing filter as shown in FIG. 15 can be observed simultaneously.

  A material having birefringence can be used for the retardation layer 11 composed of the regions A1 and A4. For example, a liquid crystal material can be used. Birefringence refers to the fact that the refractive index of a substance varies depending on the optical axis direction.For this reason, the speed of light passing through the substance varies. Only a phase difference occurs.

  In addition, the phase difference layer 11 has an optical axis arranged in a pattern in the four-axis direction. As a method of arranging the optical axis in a pattern, an aligned liquid crystal can be obtained by performing an alignment treatment on the alignment film and applying a liquid crystal thereon. For the alignment treatment of the alignment film for aligning the liquid crystal material, for example, a rubbing alignment method or a photo alignment method can be used.

  The rubbing alignment method is a method of rubbing an alignment film produced by applying a polymer solution on a substrate with a rubbing cloth. The property of the alignment film surface changes in the rubbing direction, and liquid crystal molecules are aligned in this direction. It uses properties. For the alignment film, polyimide, PVA, or the like is used.

  In the case of aligning the optical axis of the retardation layer in the four-axis direction, it is manufactured by sequentially placing the mask on the alignment film and rubbing with a cloth using a mask as shown in FIG. In this case, the rubbing direction may be changed for each mask. As a result, four regions having different orientation directions are obtained.

  In addition, the photo-alignment method irradiates the alignment film with anisotropy such as polarized light or non-polarized light from an oblique direction to induce rearrangement of molecules in the alignment film or anisotropic chemical reaction. This method utilizes the fact that liquid crystal molecules are aligned by imparting anisotropy to the alignment film. Examples of the photo-alignment mechanism include photoisotropy of azobenzene derivatives, photodimerization and crosslinking of derivatives such as cinnamic acid ester, coumarin, chalcone and benzophenone, and photolysis of polyimide and the like.

  Also in the photo-alignment method, a photomask as shown in FIG. 19 can be used. While sequentially switching the photomasks of FIGS. 19A to 19D, polarized light having different polarization directions, typically linearly polarized light or elliptically polarized light, is sequentially irradiated. Thereby, four regions which are adjacent to each other in the in-plane direction and have different alignment directions can be formed in the alignment film.

  Instead of these photomasks, a phase difference filter can also be used. For example, by irradiating polarized light, typically linearly polarized light or elliptically polarized light, through a phase difference filter having three or four regions adjacent to each other in the in-plane direction and having different slow axis directions, Three or four regions adjacent to each other in the in-plane direction and having different orientation directions can be formed by one exposure.

  As a method for forming these alignment films, known methods such as a gravure coating method and a micro gravure coating method can be used.

  Liquid crystal materials include photocurable liquid crystal monomers with acrylates at both ends of the mesogenic group, polymer liquid crystals cured with EB or UV, polymer liquid crystals with mesogenic groups in the polymer main chain, and the molecular main chain itself. A liquid crystalline polymer can be used. The orientation of these liquid crystals can be promoted by heat treatment at a temperature slightly below the NI point at which phase transition occurs after coating.

  As the support 12, an unstretched film produced by extrusion or casting, a stretched film produced by stretching, or the like can be used. The stretched film includes a uniaxially stretched film and a biaxially stretched film depending on how to stretch, and both can be used.

  These unstretched films and stretched film materials include cellophane, polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyolefin (PO), ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVA), polychlorinated. Examples thereof include vinyl, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), nylon, acrylic resin, and triacetyl cellulose (TAC) film. In particular, an unstretched film is preferable because it does not disturb the retardation value of the retardation layer provided on the support substrate.

  Examples of the material of the reflective layer 13 include a simple metal material such as Al, Sn, Cr, Ni, Cu, Au, and Ag, or a compound thereof.

A transparent reflective layer that is substantially transparent to light perpendicular to the film surface but exhibits reflection characteristics according to the refractive index with respect to oblique light can be used as a single layer or multiple layers. Examples of materials that can be used as the transparent reflective layer are listed below. The numerical value in parentheses following the chemical formula or compound name shown below indicates the refractive index n. Ceramics include Fe ₂ O ₃ (2.7), TiO ₂ (2.6), CdS (2.6), CeO ₂ (2.3), ZnS (2.3), PbCl ₂ (2.3 ), CdO (2.2), WO ₃ (5), SiO (5), Si ₂ O ₃ (2.5), In ₂ O ₃ (2.0), PbO (2.6), Ta ₂ O ₃ (2.4), ZnO (2.1), ZrO ₂ (5), MgO (1), SiO ₂ (1.45), MgF ₂ (4), CeF ₃ (1), CaF ₂ (1. 3-1.4), AlF ₃ (1), Al ₂ O ₃ (1), GaO (2) and the like. Examples of the organic polymer include polyethylene (1.51), polypropylene (1.49), polytetrafluoroethylene (1.35), polymethyl methacrylate (1.49), and polystyrene (1.60). Not limited.

  As a method for forming the reflective layer 13, a known method such as a vacuum deposition method, a sputtering method, or a CVD method can be used as appropriate. Moreover, the method of providing the ink etc. which have a light reflection effect with a well-known printing method may be sufficient.

  Further, the reflective layer 13 may be provided along the diffractive structure. As a method of providing the reflective layer 13 along the diffractive structure, a diffractive structure forming layer is provided in advance, and a relief type press plate comprising a relief hologram utilizing light interference or a fine uneven pattern forming a diffraction grating is used. After the fine concavo-convex pattern is replicated by heating and pressurizing, the reflective layer can be provided along the diffraction structure by forming the reflective layer using a known method such as the vacuum deposition method.

  The diffractive structure forming layer is preferably made of a material that has good moldability by heat, is less likely to cause press unevenness, and can provide a bright reproduced image. For example, thermoplastic resins such as acrylic resins, epoxy resins, cellulose resins, vinyl resins, acrylic resins having reactive hydroxyl groups, polyester polyols, etc. added polyisocyanates as crosslinking agents, crosslinked urethane resins, Thermosetting resins such as melamine resins and phenol resins, and ultraviolet or electron beam curable resins such as epoxy (meth) acryl and urethane (meth) acrylate can be used alone or in combination. Moreover, even if it is resin other than the above, if a diffraction structure pattern can be formed, it can be used suitably.

  The polarizing layer 14 is an absorption polarizer obtained by, for example, impregnating PVA (polyvinyl alcohol) with iodine or a dichroic dye and stretching and orienting the dichroic dye on an alignment film. A reflective circular polarizer in which cholesteric liquid crystal is aligned on a substrate, a reflective polarizer formed by laminating a birefringent multilayer film, a prism polarizer formed in a lenticular lens shape with a Brewster angle, and a birefringent material A birefringent diffractive polarizer formed in a diffraction grating shape or a diffractive polarizer in which grooves of a diffractive structure are formed deeply can be used. Other than these, any element that can separate or extract a polarized light component in a specific direction with respect to reflected light or transmitted light can be used.

  Examples of the present invention will be described below. A 38 μm thick PET film was prepared as the support 12. A diffractive structure forming layer made of urethane resin was coated on the support 12 with a thickness of 1 μm. This coating was performed by a gravure coating method.

  Next, the diffraction structure image was embossed on the surface of the diffraction structure forming layer. Thereafter, a reflective layer 13 made of aluminum was formed on the diffractive structure forming layer. The reflective layer 13 was formed using a vacuum deposition method so that the thickness was 500 mm.

  Thereafter, an alignment film was formed on the reflective layer 13 by coating the alignment film solution with a thickness of 0.1 μm by a microgravure coating method. Thereafter, a mask as shown in FIG. 19 (a) is set and rubbed with a rubbing cloth at an angle of θ1 = 0 ° with respect to the X axis, and then a mask as shown in FIG. 19 (b). Is rubbed with a rubbing cloth at an angle of θ2 = 22.5 ° with respect to the X axis, and then a mask as shown in FIG. Rub using a rubbing cloth at an angle of −45 °, and then install a mask as shown in FIG. 19 (d), at an angle of θ4 = 67.5 ° with respect to the X axis. Rubbing with a rubbing cloth. At this time, when each mask was installed, each area was installed so as not to overlap, and a rubbing process was performed.

  The second image P2 included in the display body, that is, the areas A1 and A4, is a polarized latent image portion in which the halftone dot angle between the halftone dot background portion and the halftone dot latent image portion is 30 ° as shown in FIG. An image is formed.

  Thereafter, UV curable liquid crystal UCL-008 manufactured by DIC Corporation is applied with a micro gravure so as to have a phase difference value of λ / 4, UV-cured in an oxygen atmosphere, and the optical axis direction on the four axes. A retardation layer 11 having the same structure was obtained.

  When a verification filter as shown in FIG. 17 was prepared for the display body as described above and observed, different images were observed on the left and right as shown in FIG. Since it is formed by dots, a halftone dot latent image was observed in the second image P2.

DESCRIPTION OF SYMBOLS 10 ... Display body 11 ... Phase difference layer 12 ... Support body 13 ... Reflective layer 14 ... Polarizing layer A1 ... 1st area | region A2 ... 2nd area | region A3 ... 1st 3 area A4 ... 4th area P1 ... 1st image P2 ... 2nd image 21 ... Visualization sheet 22 angle inclined with respect to X axis 30 ... Angle with X axis Polarizing filter 23 with θp = 33.75 °. Polarizing filter Q1 with angle θp = 11.25 ° with respect to the X axis. Verification filter Q2.

Claims (11)

A retardation layer including first to fourth regions adjacent to each other in the in-plane direction and having different slow axis directions in the in-plane direction,
Any two or more of the regions have a polarization latent image portion and a polarization background portion,
The polarization latent image portion is composed of halftone dots and has a halftone dot background portion and a halftone dot latent image portion,
A halftone dot constituting the halftone dot latent image portion and a halftone dot constituting the halftone dot background portion are different in that at least one of halftone dot angle, pitch, and halftone dot phase is different. Yes,
With respect to a first straight line that bisects the angle formed by the first slow axis of the first region or the first polarization latent image portion and the second slow axis of the second region or the second polarization latent image portion. ,
The angle formed by the third slow axis of the third region or the third polarization latent image portion and the first straight line is orthogonal to the fourth slow axis of the fourth region or the fourth polarization latent image portion. The angles formed by the axis and the first straight line are equal to each other,
With respect to a second straight line that bisects the angle formed by the first slow axis of the first region or first polarization latent image portion and the first slow axis of the fourth region or fourth polarization latent image portion. ,
The angle formed between the second slow axis of the second region or the second polarization latent image portion and the second straight line is orthogonal to the third slow axis of the third region or the third polarization latent image portion. A display body characterized in that an angle formed by an axis and the second straight line is equal to each other. A retardation layer including first to fourth regions adjacent to each other in the in-plane direction and having different slow axis directions in the in-plane direction,
Any two or more of the regions have a polarization latent image portion and a polarization background portion,
The polarization latent image portion is composed of lines, and has a line background portion and a line latent image portion,
The line that constitutes the line latent image part and the line that constitutes the line background part have different one or more of line angle, pitch, and line phase, Yes,
With respect to a first straight line that bisects the angle formed by the first slow axis of the first region or the first polarization latent image portion and the second slow axis of the second region or the second polarization latent image portion. ,
The angle formed by the third slow axis of the third region or the third polarization latent image portion and the first straight line is orthogonal to the fourth slow axis of the fourth region or the fourth polarization latent image portion. The angles formed by the axis and the first straight line are equal to each other,
With respect to a second straight line that bisects the angle formed by the first slow axis of the first region or first polarization latent image portion and the first slow axis of the fourth region or fourth polarization latent image portion. ,
The angle formed between the second slow axis of the second region or the second polarization latent image portion and the second straight line is orthogonal to the third slow axis of the third region or the third polarization latent image portion. A display body characterized in that an angle formed by an axis and the second straight line is equal to each other. In the in-plane direction of the retardation layer, an angle formed by the first slow axis with respect to a third straight line parallel to the main surface of the retardation layer is a first angle θ _1, and the second slow axis The second angle θ ₂ is the angle formed by the third slow axis, the third angle θ ₃ is the angle formed by the third slow axis, and the fourth angle θ ₄ is the angle formed by the fourth slow axis. The first angle θ ₁ , the second angle θ ₂ , the third angle θ ₃ , the fourth angle θ _4, and the integers L, M, and N are expressed by the relational expression θ ₂ = θ ₁ + 22.5 ° + 90 ° × L,
θ ₃ = θ ₁ + 45 ° + 90 ° × M and θ ₄ = θ ₁ + 67.5 ° + 90 ° × N
The display body according to claim 1, wherein:   The display body according to any one of claims 1 to 3, further comprising a reflective layer facing the retardation layer.   The display body according to any one of claims 1 to 3, further comprising a polarizing layer facing the retardation layer.   The display body according to claim 5, further comprising an absorption layer facing the polarizing layer.   An adhesive label comprising the display body according to any one of claims 1 to 6 and an adhesive layer provided on the display body.   A transfer foil comprising: the display body according to claim 1; and a support layer that releasably supports the display body.   A method for determining the authenticity of a display body, comprising: superimposing a polarizing sheet on the display body according to any one of claims 1 to 8 and performing authenticity determination based on the presence or absence of the appearance of a polarized latent image.   Furthermore, it is characterized by overlapping the visualization sheet formed with the visualization pattern consisting of halftone dots or line patterns, and performing true / false judgment based on the presence or absence of the appearance of halftone dots or line latent images The authenticity determination method for a display body according to claim 9.   A verification device is superimposed on the display body according to any one of claims 1 to 9, and true / false judgment is performed based on the presence or absence of the appearance of a polarization latent image and a halftone latent image or a line latent image. Authenticating method of the display object

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