JP2020179551A - Transmission latent image forming body - Google Patents

Abstract

To provide a forming body viewed as a transparent window under transmitted beam, and a latent image is viewed therefrom by changing an observation angle.SOLUTION: There is provided a transmission latent image forming body on which a latent image is formed by forming a plurality of linear cracks from the surface of a transparent or translucent substrate toward an internal direction. In the transmission latent image forming body, when observed at an angle at which a light source is incident to a thickness direction of the substrate, the latent image is not viewed, on the contrary, when observed at an angle at which a light source is incident on a cross section of the linear crack the latent image is viewed.SELECTED DRAWING: Figure 1

Description

INDUSTRIAL APPLICABILITY The present invention is not visible when observed under reflected light and is observed at a specific observation angle under transmitted light in identification cards such as passports and card products for which anti-counterfeiting technology is required. It relates to a transmitted latent image forming body in which a latent image is visually recognized only in the case.

Various identification cards, card products, etc. are required to have security, and are required to have properties that are difficult to forge or tamper with. As anti-counterfeiting measures for these card products and the like, for example, a technique of imparting a latent image by a lens effect formed by using the thickness of a base material such as a lenticular lens is known.

In addition, as a technique using a transparent base material, a light source that forms a 10,000-line pattern on the front and back surfaces of the base material with a specific pitch and a specific image width and is observed through the transparent base material is placed on the front and back surfaces. A technique is known in which a change in the amount of transmitted light causes a continuous difference in brightness when the substrate is tilted and observed due to the relationship of the formed all-wire pattern (see, for example, Patent Document 1).

The technique of Patent Document 1 is a configuration in which a universal pattern formed on either the front or back surface is formed in a different color, or a part of the universal pattern formed on either the front or back surface is formed by changing the pitch. It is a technique that can give a pattern with shading and color change.

On the other hand, the applicant has a uniform image or dot pattern divided into a message image portion and a background on the front surface side as a printed matter in which image lines or dot patterns are formed on the front and back surfaces of a light-transmitting base material. In the message image portion and the background image portion, slit patterns that cannot be visually recognized with the naked eye are formed along different directions, and image lines or dot patterns formed on the front surface side are formed on the front surface side. An application has been filed for a true / false discriminant printed matter using a minute slit image in which a latent image image appears when the printed matter is observed from directly above or tilted when it is formed at a position that matches or is different from the pattern (for example). , Patent Document 2).

Japanese Patent No. 2802484 JP-A-2002-254791

However, the techniques of Patent Document 1 and Patent Document 2 utilize that when a specific pattern is formed on the front and back surfaces of a transparent base material and the specific patterns on the front and back surfaces are observed overlapping under transmitted light. , The color change and the message image are visually recognized. These techniques have the problem of being inferior in designability because a specific meaningless reflected image is visually recognized when observed from the front and back surfaces of the base material under reflected light.

Further, in the techniques of Patent Document 1 and Patent Document 2, since the patterns formed on the front and back surfaces of the transparent base material interfere with each other to cause a latent image to appear, the image to be given or the color change is limited. There was a lot of room for improvement from the viewpoint of expressing the anti-counterfeiting effect.

The present invention aims to solve the above-mentioned problems, and in particular, by forming linear cracks inside the base material that match the original image of the latent image on a transparent or translucent base material, light We have devised a transmission latent image forming body in which a latent image is visually recognized at a specific observation angle below.

In the transmission latent image forming body of the present invention, a plurality of linear cracks are formed in at least a part of a transparent or translucent base material in the internal direction from one surface of the base material to the other surface. It has an image portion, and the latent image portion has a first latent image pattern in which a plurality of linear cracks are formed along the first direction, and the latent image portion is oriented in the depth direction of the linear cracks. On the other hand, it is a transmission latent image forming body characterized in that the first latent image pattern is visually recognized when observed from an oblique direction.

Further, the plurality of linear cracks in the transmission latent image forming body are the transmission latent image forming bodies characterized by having a color different from that of the base material.

Further, the first latent image pattern in the transmitted latent image forming body is a transmitting latent image forming body characterized by being a continuous gradation image.

Further, the latent image portion in the transmitted latent image forming body has an nth latent image pattern in which a plurality of linear cracks are formed along an nth direction (n is a natural number of 2 or more) different from the first direction. The transmission latent image forming body is characterized in that the nth latent image pattern is visually recognized when observed from an oblique direction with respect to the depth direction of the linear crack in the nth latent image pattern. is there.

Further, the nth latent image pattern in the transmitted latent image forming body is formed by a pattern having the same shape as the first latent image pattern or a pattern in which a part of the shape continuously changes, and the first latent image pattern is formed. It is a transmission latent image forming body characterized in that the first direction to be formed and the nth direction forming the nth latent image pattern are continuously changed and arranged.

Further, the method for producing a transmitted latent image forming body of the present invention is a method of producing a transmitted latent image forming body in which a latent image is observed on at least a part of a transparent or translucent base material at a specific observation angle under transmitted light. In the manufacturing method, a coating step of applying a solvent and / or ink to one surface of a base material according to the shape of a latent image image and a stress on the base material to which the solvent and / or ink is applied by the coating step are applied. Is a method for producing a transmission latent image forming body, which comprises at least a stress application step of applying a stress to form a plurality of linear cracks from the surface of the base material toward the inside.

Further, it is a method for producing a transmission latent image forming body, which further includes a cleaning step of cleaning the solvent and / or ink applied to the surface of the base material after the stress application step.

Since the transmitted latent image forming body of the present invention forms a latent image by forming a plurality of linear cracks from one surface side of the transparent or translucent base material to the inside of the base material, it is reflected. Since the latent image is not visually recognized under light, the effect of the transparent window is obtained under transmitted light, and the latent image is visible only at a specific observation angle under transmitted light, the design under reflected light is improved. Can be secured.

Further, in the transmission latent image forming body of the present invention, the direction in which linear cracks are generated can be arbitrarily set. Therefore, by changing the angle of the light incident on the linear crack, it is possible to obtain the effect of changing the latent image and the dynamic latent image effect.

An example of a card product is shown as a transmission latent image forming body. An example of the cross-sectional structure of the transmission latent image forming body is shown. The latent image image visually recognized by the observation angle is shown. The block diagram of the fabrication system for producing a transmission latent image forming body is shown. A method for producing a transmission latent image forming body is shown. An example of the original image and the printing plate surface in the process of producing the transmission latent image forming body is shown. The process of generating a linear crack by applying stress is shown. An example of the transmission latent image forming body in the second embodiment is shown. The observation conditions and the visual image of the transmitted latent image forming body in the second embodiment are shown. A modification of the transmission latent image forming body in the second embodiment is shown. The observation conditions and the visual image of the transmitted latent image forming body in Example 2 are shown.

A mode for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments described below, and includes various other embodiments within the scope of the technical ideas described in the claims.

(First Embodiment)
The latent image forming body (1) (hereinafter, referred to as “forming body”) according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1A is an example of a card product as a formed body (1) of the present invention, and as shown in the enlarged view of FIG. 1B, a window portion (3) is formed on at least a part of the card product. Is formed, and the latent image portion (4) is formed in the window portion (3). Further, the base material (2) on which the window portion (3) is formed needs to be transparent or translucent, and the material is a general plastic material used for card products such as PET, PETG, and polycarbonate. It is not particularly limited as long as it is a resin material.

In the formed body (1) in the first embodiment, an example in which the window portion (3) is formed in a part of the card product will be described, but the configuration in which the entire surface of the card product is the formed body (1), paper, etc. A part of the product mainly made of a material other than plastic may be cut, and a base material (2) such as plastic may be applied to the part to form the formed body (1).

Further, the formed body (1) of the present invention forms a latent image portion (4) by generating a plurality of linear cracks (5) in the above-mentioned base material (2), and the method thereof is as follows. , An organic solvent or the like is applied to an arbitrary part of the base material (2), and stress is applied to the base material (2), or the base material (2) is bent to form a plurality of lines on the base material (2). The shape crack (5) is generated to form the latent image portion (4). When applying this organic solvent or the like, it is organic along the first direction (S1 direction in the figure) that reflects the light source when observing the latent image according to the shape of the original image that is the basis of the latent image. By applying a solvent or the like, a latent image portion (4) formed by a plurality of linear cracks (5) matching the shape of the latent image image can be formed. The phenomenon in which this linear crack (5) occurs is generally called a "solvent crack", and by forming this linear crack (5) in the window portion (3), it is latent depending on the observation angle. It is possible to obtain a formed body (1) in which the image portion (4) is visually recognized.

Next, the configuration of the formed body (1) will be described with reference to FIG. FIG. 2A shows an enlarged view of the formed body (1), and a star-shaped latent image portion (4) is formed in the window portion (3). FIG. 2B shows a cross-sectional view of AA'in the enlarged view of FIG. 2A, and the region where the latent image portion (4) is formed is along the first direction. A plurality of linear cracks (5) formed linearly and substantially perpendicular to the thickness direction of the base material (2) are formed.

The latent image image that can be given to the formed body (1) of the present invention can be formed in any shape such as characters, logo marks, and face images, and an organic solvent or the like is applied according to the latent image image. However, any image can be given by changing the length and density of the linear crack (5). The granting method will be described later.

Next, the principle that the latent image image is visually recognized by the linear crack (5) formed in the formed body (1) of the present invention will be described with reference to FIG. FIG. 3A was observed at a position where the light source (7) was incident in the depth direction of the linear crack (5) formed in the internal direction of the base material (2) with the formed body (1) sandwiched between them. It shows the state, and when the light source (7) is incident along the thickness direction of the base material (2), the light is not scattered by the linear crack (5), so that the linear crack There is no difference in the amount of transmitted light between the region where (5) is formed and the region where (5) is not formed. Therefore, since the latent image portion (4) cannot be visually recognized separately, it is visually recognized as a mere transparent window.

On the other hand, FIG. 3B shows that the light incident on the formed body (1) is incident on the cross section of the linear crack (5) with respect to the depth direction of the linear crack (5). It shows an image observed from an oblique direction, and when light is incident on the base material (2) from the upper direction to the lower direction, the light source (7) is incident on the cross section of the linear crack (5). As a result, light scattering occurs, and a difference occurs in the amount of transmitted light between the region where the linear crack (5) is formed and the region where the linear crack (5) is not formed. As a result, the star-shaped latent image portion (4) is visually recognized. In the present invention, as a state of observing the linear crack (5) from an oblique direction with respect to the depth direction, the light source (7) is directed from the upper direction to the lower direction with respect to the cross section of the linear crack (5). As described in the case of the incident, the base material (2) is tilted and observed so that the light source (7) is incident on the linear crack (5) cross section, and the light is transmitted by the linear crack (5) cross section. If the angle is such that scattering occurs, there is a difference in the amount of transmitted light between the region where the linear crack (5) is formed and the region where the linear crack (5) is not formed, and the latent image can be visually recognized.

FIG. 4 is a block diagram showing a manufacturing system (S) for manufacturing the formed body (1). The manufacturing system (S) includes at least an input unit (101), a processing unit (102), an output unit (103), and a processing unit (104).

The input unit (101) is a means for inputting data necessary for producing the formed body (1) in the first embodiment and giving input information to the processing unit (102). The processing unit (102) is a means for performing arithmetic processing and image processing necessary for producing the formed body (1) and giving the obtained result to the output unit (103). The output unit (103) is a means for outputting the data given by the processing unit (102) by an external, for example, a printing machine (not shown). Further, the processing unit (104) is a means for applying stress to the base material printed or the like by the output unit (103). The processing unit (102) may further have a storage unit (105) for recording the given data and the produced data.

Next, the method of producing the formed body (1) in the first embodiment will be described with reference to FIGS. 5 and 6. As shown in FIG. 5, the method for producing the formed body (1) of the present invention includes an original image setting step (STEP1), a solvent application step (STEP2), a stress application step (STEP3), and a cleaning step (STEP4). Is. However, as essential steps for producing the formed body (1) of the present invention, a solvent coating step (STEP2) of applying an organic solvent or the like according to the shape of the latent image image and a group coated with the organic solvent or the like are performed. This is a stress application step (STEP 3) in which a stress is applied to the material (2), and if at least these are present, a latent image image due to linear cracks (5) can be formed.

First, in the original image setting step of STEP 1, the original image data that is the basis of the latent image is acquired from the input unit (101), or the image data registered in advance in the storage unit (105) is acquired and the original image is acquired. Set the image (8). In the present embodiment, an example in which the star-shaped original image (8) shown in FIG. 6A is set will be described, but the original image (8) is not particularly limited in terms of characters, patterns, patterns, and the like. It can be any image. Further, an image created by another system different from the system (S) shown in FIG. 4, an image processing software, or the like may be used.

Next, the solvent coating step of STEP 2 will be described. In the solvent coating step, an organic solvent or the like is coated on the base material (2) as shown in FIG. 7 (a) based on the original image (8) created in the original image setting step. In the solvent coating process, when ink or the like is directly applied by a method using digital data such as inkjet printing, it is possible to form variable information using different data for each sheet as the original image (8). Is. If it is desired to continuously form the same original image (8), a printing plate surface (9) for forming the original image (8) created in the original image setting step is prepared, and offset printing, letterpress printing, or the like is performed. An organic solvent or the like may be applied as shown in FIG. 6C by a known printing method. This method is suitable for producing a large number of formed bodies (1) by continuous printing.

Further, when a continuous gradation image having shading is used for the original image (8), a printing plate produced by a method similar to the gradation expression by halftone dots widely used as existing printing can also be used. In this case, the gradation of the pattern at the time of observation can be expressed by the density of the linear cracks (5). However, in consideration of the original image (8) that can be observed in the formed body (1), it is necessary to prepare the plate surface used for printing based on the negative / positive inverted data.

Next, as a stress application step of STEP3, as shown in FIG. 6D, stress is applied to the base material (2) coated with 4 organic solvents or the like in the solvent coating step of STEP2. For example, the base material is bent. In the example of FIG. 6D, a sheet-like base material (2) having a smooth surface is used, and the stress is applied by bending in the vertical direction, but the stress is partially changed and applied. It is also possible to change the density of the linear cracks (5) formed inside the base material (2) by using the method of, in which case, the density of the linear cracks (5) causes the floor. Can express the key.

Next, the principle of generating linear cracks (5) inward from the surface of the base material (2) will be described with reference to the cross-sectional view of FIG. 7. As shown in FIG. 7 (a), the base material (2) in a state where an organic solvent or the like is applied to the surface is bent and stressed as shown in FIG. 7 (b). As shown in FIG. 7 (c), a linear crack (5) is generated in a direction substantially perpendicular to the stress application direction. In this way, linear cracks (5) are generated along the region on the surface of the base material (2) to which the organic solvent is applied. Therefore, as shown in the example of FIG. 6 (d), a star-shaped original is formed. In the image (8), a plurality of linear cracks (5) extending in the lateral direction are formed.

Since the length and sparseness of the linear cracks (5) formed on the base material (2) vary depending on the material of the base material (2), the type of solvent, and the degree of stress applied, the formed body ( It may be set appropriately in consideration of the visual state at the time of observation in 1). In accordance with this design, the region to be observed deeply causes more cracks (5), and the region to be observed lightly causes a small amount of cracks (5) to achieve continuous gradation like a photographic image. It is possible to form a latent image (not shown) having.

Finally, as a cleaning step of STEP 4, the solvent applied to the surface of the base material (2) is naturally dried or wiped off with a waste cloth or the like to clean the surface of the base material (2), as shown in FIG. 7 (d). As shown, a formed body (1) in which linear cracks (5) are generated from the surface of the base material (2) to the other surface can be produced.

As shown in FIG. 3A, the formed body (1) produced by these methods has a light source (1) in the depth direction of the linear crack (5) generated in the thickness direction inside the base material (2). When observed at the position where 7) is incident, the star-shaped latent image portion (4), which is the original image (8), is almost invisible, but as shown in FIG. 3 (b), it is linear. When observed at an angle at which the light source (7) is incident on the cross section of the crack (5), the light incident on the cross section of the linear crack (5) is scattered, so that the region where the linear crack (5) is formed is formed. In the region where the light is not formed, a difference occurs in the amount of transmitted light, and the star-shaped latent image portion (4) is visually recognized.

(Second Embodiment)
The formed body (1') in the second embodiment of the present invention will be described. The second embodiment has a configuration in which a plurality of latent image images due to the linear cracks (5) formed in the first embodiment are provided. Since the method and principle for forming the linear crack (5) on the base material (2) are the same as those in the first embodiment, the description thereof will be omitted.

The formed body (1') in the second embodiment is formed by a first linear crack (5') formed along the first direction (S1 in the figure) as shown in FIG. A second latent image portion (4 ″) formed by a first latent image portion (4 ″) formed and a second linear crack (5 ″) formed along a second direction. ) Are superimposed and formed. In the second embodiment, the star-shaped first latent image portion (4') is formed by the first linear crack (5'), and the second linear crack (5'') forms the star-shaped first latent image portion (4'). It forms a crescent-shaped second latent image (4 ″).

The effect of the formed body (1) in the second embodiment will be described with reference to FIG. As shown in FIG. 9A, the formed body (1') in the second embodiment was observed toward the linear crack (5) formed in the internal direction of the base material (2). In this case, the first latent image portion (4') formed as a star-shaped image and the second latent image portion (4'') formed as a crescent-shaped image can hardly be visually recognized, but FIG. 9 ( As shown in b), when the base material (2) is tilted at an angle at which the light source (7) is incident on the cross section of the first linear crack (5') of the formed body (1'), the first is observed. Since light is scattered in the cross section of the linear crack (5) of 1, there is a difference in the amount of transmitted light between the region formed by the first linear crack (5') and the region not formed. , Only the star-shaped first latent image portion (4') is visually recognized. Further, as shown in FIG. 9 (c), when the base material (2) is tilted at an angle at which the light source (7) is incident on the cross section of the second linear crack (5 ″), the second is observed. Since light is scattered in the cross section of the linear crack (5 ″), there is a difference in the amount of transmitted light between the region where the second linear crack (5 ″) is formed and the region where the second linear crack (5 ″) is not formed. Is generated, and only the crescent-shaped second linear crack (5 ″) is visible.

In the second embodiment, a configuration is described in which a plurality of latent image images can be formed by forming patterns by linear cracks (5) along different directions based on the two original images. However, as shown in FIG. 10, two or more same original images are used to form latent images due to linear cracks (5, 5', 5', 5',') at different angles, and the light source is used. When observing while changing the angle incident on the cross section of the linear crack (5) (visualizing by rotating the forming body (1) in the direction of the arrow in the figure), the latent image image is visually recognized as rotating. The effect can be obtained. In FIG. 10, as an example of being visually recognized when the forming body (1) is rotated, in the state shown in FIG. 10A, a light source is incident on the cross section of the first linear crack (5). Since the observation is performed at an angle, the star-shaped latent image formed by other linear cracks (5', 5', 5',') is not visible, but as shown in FIG. 10 (b). In addition, when the forming body (1) is rotated in the direction of the arrow, light is scattered by the cross section of the second linear crack (5'), and when it is further rotated, the third linear crack (5') is generated. A dynamic effect is obtained in which the observed image gradually changes into a star-shaped latent image formed by cracks (5 ″).

Further, as an application example of the configuration described with reference to FIG. 10, in addition to visually recognizing a dynamic latent image by observing the formed body (1) while rotating it, the shape of the original image (8) is gradually changed. By changing it, it is possible to have a configuration that changes to a different image. In the configuration in which these latent image images are deformed, various configurations such as scaling and rotation of the image are possible, and all configurations that can be formed by the linear crack (5) described in the claims. Is, of course, within the scope of the present invention.

Further, the latent image image of the present invention can be a continuous gradation image such as a photographic image, and an inkjet printer ink or the like is used as an organic solvent or the like to be applied to the base material (2). It is also possible to form a color latent image. As a production method, the original image (8) is used as a gradation image using the method described in the first embodiment, and a linear crack (5) is formed on the base material (2) using an inkjet printer. It can be produced by.

Examples of the formed body of the present invention will be described below, but the present invention is not limited to this example.

(Example 1)
FIG. 1 shows the formed body (1) in the first embodiment, in which a window portion (3) is formed on a part of a card-shaped base material (2), and the window portion (3) of the present invention is formed. The form (1) is added. As shown in FIG. 6A, the formed body (1) in this example formed a latent image portion (4) by linear cracks (5) using a star-shaped original image (8).

As the base material (2), a polycarbonate base material (2) (ECG101S manufactured by Sumitomo Bakelite) having a thickness of 0.5 mm is used, and a printed image of a tint block pattern, personal information, etc. Was formed.

FIG. 6 shows a latent image image of the formed body (1) in this embodiment. As the star-shaped original image (8) shown in FIG. 6 (a), an image selected from a database registered in advance was used. Further, in this embodiment, it is assumed that a large number of card products to which a star-shaped latent image image selected from the database is attached is produced, and the printing plate surface shown in FIG. 6B is used in the solvent coating step.

Next, using the printing plate surface (9) shown in FIG. 6 (b), a colorless solvent ink is printed on the window portion (3) of the base material (2) by a letterpress printing machine, and a star-shaped latent image image is obtained. Was formed. Regarding the stress application step of applying stress to the base material (2) coated with the solvent ink, as shown in FIG. 6 (d), a plurality of stresses are applied by applying stress so as to bend the base material (2). A linear crack (5) was generated.

Regarding the stress application step of bending the base material (2), both ends of the base material (2) in which the original image (8) which is the base of the latent image is applied on the base material (2) by the solvent ink. Is fixed, a cylindrical roll is pressed from the back surface side of the base material (2), stress is applied by bending the base material (2), and a linear crack (5) is applied to the surface of the base material (2). Was generated. The density of the linear cracks (5) varies depending on the material, thickness and solvent of the base material (2) to be selected, but it is based on setting the diameter of the cylindrical roll pressed against the base material (2) to be small. The force for bending the material (2) is increased, and finer linear cracks (5) can be densely imparted. Further, by forming by partially changing the stress applied to the base material (2), it is possible to partially change the density of fine cracks, and the photographic gradation image is the same as the original image (8). You can also do it.

Finally, stress was applied to wipe off the solvent ink adhering to the surface of the base material (2) in which linear cracks (5) were formed on the surface, and the surface was naturally dried.

As shown in FIG. 3A, the latent image image of the formed body (1) produced by the above step is obtained with respect to the cross section of the linear crack (5) formed inside the base material (2). When observed at an angle at which the light source (7) is vertically incident, it was almost impossible to visually recognize the star-shaped latent image which is the original image (8), but as shown in FIG. 3 (b), When the light source (7) was observed at an angle of incidence on the cross section of the linear crack (5) of the formed body (1), the star-shaped latent image image which was the original image (8) was visually recognized.

(Example 2)
Next, the formed body (1) of Example 2 will be described. In the formed body (1) of the second embodiment, a color latent image is formed by forming a plurality of hues inside the linear crack (5). In the second embodiment, an image of cherry blossom petals is used as the original image (8), digital data of an image in which the color of the petals is changed in gradation toward the center of the image is created, and an inkjet printer (EP-880AW manufactured by Epson) is created. ) Was used to print directly on the substrate (2).

As the base material (2), the base material (2) made of polycarbonate used in Example 1 was used, and a latent image was given to the plastic base material (2) whose entire surface was transparent.

In the production of the formed body (1) of Example 2, a color original image (8) is printed on the surface of the base material (2) using an inkjet printer, and both ends of the printed base material (2) are printed. A cylindrical roll is pressed from the back surface side of the base material (2) from the back surface side in a fixed state, and stress is applied by bending the base material (2) to apply a linear shape to the front surface of the base material (2). Crack (5) was generated (not shown).

Then, the excess inkjet ink adhering to the surface of the base material (2) was wiped off, and the inkjet ink that had entered the inside of the linear crack (5) was naturally dried.

As shown in FIG. 11A, the latent image of the formed body (1) of Example 2 is obtained with respect to the cross section of the linear crack (5) formed in the thickness direction inside the base material (2). When observed at a position where the light source (7) is incident in the vertical direction, the image (4) of the cherry blossom petals formed by the gradation, which is the original image (8), is almost invisible, but FIG. As shown in b), when observed at an angle at which the light source (7) is incident on the cross section of the linear crack (5) of the forming body (1), the cherry blossoms formed by the gradation which is the original image (8). The image of the petals (4) was visually recognized.

1, 1 ′, 1 ″ transmission latent image forming body 2 base material 3 window portion 4, 4 ′, 4 ″ latent image portion 5, 5 ″, 5 ″, 5 ″ ″ linear crack 6 viewpoint 7 Light source 8 Original image 9 Printing plate surface 10 Solvent 11 Ink layer

Claims (7)

At least a part of the transparent or translucent base material has a latent image portion in which a plurality of linear cracks are formed in the internal direction from one surface of the base material to the other surface.
The latent image portion has a first latent image pattern in which a plurality of the linear cracks are formed along the first direction, and the latent image portion is arranged with respect to the depth direction of the linear cracks. A transmission latent image forming body, characterized in that the first latent image pattern is visually recognized when observed from an oblique direction. The transmitted latent image forming body according to claim 1, wherein the linear crack has a color different from that of the base material. The transmission latent image forming body according to claim 1 or 2, wherein the first latent image pattern is a continuous gradation image. The latent image portion has an n-th latent image pattern in which a plurality of linear cracks are formed along an nth direction (n is a natural number of 2 or more) different from the first direction. When observed from an oblique direction with respect to the depth direction of the linear crack in the nth latent image pattern,
The transmitted latent image forming body according to any one of claims 1 to 3, wherein the nth latent image pattern is visually recognized. The first latent image pattern has the same shape as the first latent image pattern, or is formed by a pattern in which a part of the shape continuously changes to form the first latent image pattern. The transmitted latent image forming body according to claim 4, wherein the direction of the nth and the nth direction forming the nth latent image pattern are continuously changed and arranged. A method for producing a transmitted latent image forming body in which a latent image is observed at a specific observation angle under transmitted light on at least a part of a transparent or translucent substrate.
A coating step of applying a solvent and / or ink to one surface of the base material according to the shape of the latent image.
At least having a stress application step of applying stress to the base material to which the solvent and / or the ink is applied by the coating step to form a plurality of linear cracks from the surface of the base material to the inside. A method for producing a transmission latent image forming body. The method for producing a transmitted latent image-forming body according to claim 6, further comprising a cleaning step of cleaning the solvent and / or the ink applied to the surface of the base material after the stress application step.

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