JP5964717B2 - Covering member - Google Patents

Description

  The present invention relates to a technique for imparting an authenticity determination function to a shrink film (also referred to as a shrink film) used for packaging a liquid container or the like.

  As an identification medium, a technique for performing hologram processing on a cholesteric liquid crystal is known (for example, see Patent Document 1). Moreover, the technique which provides a window in the shrink film which covers a drink bottle, and pastes a hologram from the inner side is known (for example, refer patent document 2).

Japanese Patent No. 4268336 Japanese Patent No. 5014405

  An identification medium using a cholesteric liquid crystal described in Patent Document 1 performs identification using an optical characteristic that selectively reflects circularly polarized light in a specific turning direction of the cholesteric liquid crystal. When applied to the shrink film, there arises a problem that the discrimination function using circularly polarized light in a specific turning direction is hindered. That is, in general, the shrink film is obtained by stretching a resin film under a specific temperature condition, and placing the stretched film in the environment of the previous specific temperature condition (or experimentally determined temperature condition) It utilizes the phenomenon of shrinking (shrinking) to return from the stretched state.

  By the way, when a resin film is stretched, birefringence (refractive index anisotropy) appears by stretching, but the stretched state does not completely return when shrunk, so the shrunk film in a shrunk state Indicates birefringence. For this reason, when the cholesteric liquid crystal is observed through the contracted film in the contracted state, the polarization state of right circularly polarized light or left circularly polarized light selectively reflected from the cholesteric liquid crystal is disturbed when transmitted through the contracted film. As a result, when switching between the right circular polarizing filter and the left circular polarizing filter and observing, the switching of the presence or absence of visual recognition of the reflected light becomes ambiguous, and the identification function is deteriorated. In other words, when there is no disturbance in the polarization state, an optical function is obtained in which the reflected light from the cholesteric liquid crystal can be seen by the right circular polarizing filter and not visible by the left circular polarizing filter (or vice versa). However, if the polarization state disturbance described above occurs, the reflected light from the cholesteric liquid crystal can be seen by the right circular polarization filter and also by the left circular polarization filter, and the discriminability is lowered.

  In such a background, the present invention selectively observes right-turning or left-turning circularly polarized light when an optical functional layer that selectively reflects circularly polarized light in a specific turning direction through a shrink film is observed. It aims at providing the technology that can do.

  The invention according to claim 1 is characterized in that at least a part of the film covering at least a part of the object by being contracted has a transparent film, and the at least part of the film is specified on the side in contact with the object. An optical functional layer that selectively reflects circularly polarized light in the swiveling direction of the film, and the film shrinks and covers the object, the optical characteristics that do not disturb the polarization state of transmitted light or (nλ / 2) A covering member characterized by having optical characteristics that function as a plate (n is an odd number).

  According to the present invention, the polarization state of the circularly polarized light transmitted through the film imparted with the contracting property is not disturbed, or the rotation direction of the circularly polarized light transmitted through the film is reversed, so that observation through the left and right circularly polarized filters is performed. The switching of whether or not the reflected light from the optical functional layer is visible can be clearly obtained.

  If the part in which the optical functional layer is provided is transparent in the film of the present invention, the other part may not be transparent (of course, the whole may be transparent). The term “transparent” means that there is a visible light transparency that allows the other side to be seen through. Therefore, the term “transparent” used in the present specification includes not only the case of being literally transparent but also the case of translucency in which the other side is transparent although it is colored or cloudy.

  In the present invention, the object to be coated is not limited, and examples thereof include a bottle containing a beverage. Here, the material of the bottle is not limited, and examples thereof include glass, resin, earthenware, metal, and wood. The coating may be at least a part of the object, and may be a part or all of the object. The covering may be in a state where the covering member does not move relative to the object by tightening the object, or in a state where the covering member can move relative to the object in the covered state.

  According to a second aspect of the present invention, in the first aspect of the present invention, the optical functional layer is a cholesteric liquid crystal layer. The cholesteric liquid crystal layer has a characteristic of selectively reflecting light having a specific center wavelength in a specific turning direction. For example, when the cholesteric liquid crystal layer is set to selectively reflect right circularly polarized light, the reflected light from the cholesteric liquid crystal layer appears when viewed through the right circularly polarized filter, but the left circularly polarized filter is used. The right circularly polarized light is blocked by the left circularly polarizing filter and cannot be seen. Authentication can be determined using this switching.

  The invention described in claim 3 is the invention described in claim 2, wherein the cholesteric liquid crystal layer is subjected to hologram processing. According to the second aspect of the present invention, in the observation with the left and right circular polarization filters being switched, it is possible to perform the discrimination based on the presence or absence of the observation of the hologram image, and high discrimination can be obtained.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein perforations are formed in the film and the optical function layer. According to invention of Claim 4, when it tries to remove the said film from a target object, a fracture | rupture arises in a perforation and the trace remains clearly. In particular, by forming a perforation in the optical functional layer, the optical functional layer also breaks at the same time, and the trace can be clearly recognized. For this reason, the effect which prevents the unauthorized reuse of the said covering member increases.

  The invention according to claim 5 is characterized in that, in the invention according to any one of claims 1 to 4, the film is stretched in a direction perpendicular to the shrinking direction. The shrink film utilizes the property of being stretched in a heated state and shrinking along this stretching direction when reheated. On the other hand, birefringence appears by stretching a resin film. The present invention is characterized in that a (nλ / 2) plate (n is an odd number) is formed by eliminating or controlling the birefringence generated by stretching for obtaining the shrinkage characteristics. According to the invention described in claim 5, apart from stretching for shrinkage, birefringence effect by stretching for shrinkage is performed by stretching at normal temperature in which shrinkage does not occur in a direction orthogonal to the stretching direction. The refractive index anisotropy is controlled so as to cancel or to intentionally form an (nλ / 2) plate. That is, in the invention described in claim 5, in addition to stretching for causing shrinkage, stretching in a direction perpendicular to the stretching is performed so that there is no refractive index anisotropy or the intended refractive index anisotropy. The state with is realized.

  According to the present invention, there is provided a technique capable of selectively observing right-turning or left-turning circularly polarized light when an optical functional layer that selectively reflects circularly polarized light in a specific turning direction through a shrink film is observed. Provided.

It is a perspective view of an embodiment. FIG. 2 is a partial cross-sectional view of FIG. 1.

(Construction)
1. First Embodiment FIG. 1 shows a shrink film 100. The shrink film 100 is made of a polystyrene film having a thickness of 50 μm that transmits visible light. Although the thickness of the shrink film 100 is not specifically limited, For example, it can select from the range of about 10 micrometers-200 micrometers. Here, although the example which comprises the shrink film 100 with a polystyrene film is demonstrated, as a constituent material of a shrink film, resin materials which permeate | transmit visible light, for example, PET (polyethylene terephthalate), PP (polypropylene), PVC (polyvinyl chloride) ), Composite materials thereof, and the like can be used. The shrink film 100 is formed into a cylindrical shape as shown by connecting film-like ones by thermocompression bonding or solvent bonding at a welding portion (not shown).

  The shrink film 100 is constituted by a film that is mechanically stretched in the circumferential direction in the cylindrical shape in the figure in a temperature environment of about 80 ° C. to 100 ° C. When the shrink film 100 is put on a lid portion such as a PET bottle or a glass bottle and heated to the above temperature, the stretched product shrinks (shrinks) to return to its original state, and the PET bottle is in a state along the shape of the lid. Then, the shrink film 100 comes into close contact with the glass bottle and functions as a cap seal. Note that the above temperature condition is an example, and the details thereof vary depending on the manufacturing conditions, material, thickness, and the like of the film material constituting the shrink film 100, and therefore experimentally obtained values are used.

  Here, in the contracted state, the shrink film 100 is adjusted to optical characteristics that do not disturb the polarization state of transmitted visible light. Note that it is possible to adjust the optical characteristics so as not to disturb the polarization state of transmitted visible light before the contraction. In this case, when contracted, the refractive index in the contracted direction slightly changes, and a slight birefringence appears. Although the effect is slight, it can be used practically. Of course, it is more preferable to adjust the optical characteristics so as not to disturb the polarization state of visible light transmitted in the final contracted state.

  FIG. 2 shows a cross-sectional view of a portion 103 in FIG. As shown in FIGS. 1 and 2, a printed layer 101 is formed on the surface of the shrink film 100. The print layer may be provided on the back surface of 100. The print layer 101 is printed with ordinary ink, and a pattern such as a color for decoration, characters and figures is formed by this printing. A rectangular window 102 is provided in a part of the printing layer 101. The identification medium 200 is fixed to the back side of the window 102, that is, the side of the window 102 that is in contact with the object to be coated of the shrink film 100. The surface of the shrink film 100 is exposed in the portion of the window 102, and the identification medium 200 on the back surface side can be observed from there through the shrink film 100.

  The identification medium 200 has a structure in which a base film 201, a cholesteric liquid crystal layer 202, and a transparent adhesive layer 204 are laminated. The base film 201 is a base material that supports the cholesteric liquid crystal layer 202, and for example, a resin film such as a PET film or a TAC (triacetyl cellulose) film is used.

  The cholesteric liquid crystal layer 202 is an example of an optical function layer. The cholesteric liquid crystal layer 200 is set to have a characteristic of selectively reflecting red right circularly polarized light. The turning direction of the circularly polarized light selectively reflected by the cholesteric liquid crystal layer 202 may be left circularly polarized light. The wavelength selectively reflected by the cholesteric liquid crystal layer 202 is not limited to the wavelength corresponding to red, and may be other wavelengths such as green as long as the wavelength is visible.

  The cholesteric liquid crystal layer 202 is subjected to hologram processing 203 in which an emboss pattern is formed by pressing a mold. A hologram pattern for identification is formed by the hologram processing 203. The hologram design is such that characters, figures, etc. can be identified. The transparent adhesive layer 204 is made of an adhesive material that transmits visible light. The identification medium 200 is affixed to the portion of the shrink film 100 that contacts the back side of the window 102 by the transparent adhesive layer 204.

  The shrink film 100 is provided with perforations 103a and 103b. The perforations 103 a and 103 b are also formed so as to cover the identification medium 200. The perforations 103a and 103b are formed on the shrink film 100 and the identification medium 200 using a processing device for forming perforations when the identification medium 200 is fixed to the shrink film 100 and the state shown in FIG. 2 is obtained. The Further, a knob 104 is provided on an extension line of the elongated region sandwiched between the perforations 103a and 103b. The knob 104 is a part for pinching with a finger protruding outward in the axial direction from the shrink film 100 processed into a cylindrical shape. When removing the shrink film 100 from an object (for example, a bottle for drinking water), the perforations 103a and 103b are broken by picking the knob 104 with a finger and pulling it upward in FIG.

(Manufacturing method of shrink film)
An example of the manufacturing method of the shrink film 100 shown in FIGS. 1 and 2 will be described. Here, an example will be described in which a product having characteristics that do not disturb the state of polarization of transmitted visible light in a contracted state is manufactured.

(1) First, a transparent resin film (for example, a polystyrene film) is prepared. This is stretched in an environment of normal temperature (for example, 18 ° C. to 25 ° C.) to give a predetermined birefringence (refractive index anisotropy). (2) The resin film obtained in (1) is stretched under a predetermined temperature environment (for example, 80 ° C. to 100 ° C.), and imparts the property of shrinking when reheated. At this time, the film is stretched in a direction different from that of (1) by 90 degrees. (3) The resin film cooled after the treatment of (2) is reheated (for example, 80 ° C. to 100 ° C.) to shrink the resin film. (4) The birefringence in the final contracted state is measured.

In (4), when birefringence remains, the conditions of (1) are changed, and the operations of (1) to (4) are repeated for another sample. And if the state in which the birefringence of the said resin film is not observed by the measurement in (4) is obtained (or it becomes below an acceptable level), the conditions of (1) in that case will be employ | adopted, and the shrink film 100 may be used. To manufacture. In addition, when manufacturing the thing of the characteristic which does not disturb the polarization | polarized-light state of visible light permeate | transmitted in the step before shrinking, the process of (3) is skipped and the same operation | work is performed.

(Identification function)
Here, a description will be given for a state in which the portion including the vicinity of the lid of the beverage bottle is covered with the shrink film of FIG. 1 by being shrunk by heating. When the window 102 is directly observed in this state, red reflected light from the cholesteric liquid crystal layer 202 is observed, and a red hologram image resulting from the hologram processing 203 is observed.

  When the window 102 is observed through the right circular polarization filter that selectively transmits the right circular polarization, the reflected light of the red right circular polarization from the cholesteric liquid crystal layer 202 is transmitted through the right circular polarization filter. It can be selectively visually recognized, and can be observed more clearly than when the red hologram image caused by the hologram processing 203 is directly viewed.

  Further, when the window 102 is observed through the left circular polarization filter that selectively transmits the left circular polarization, the reflected light of the red right circular polarization from the cholesteric liquid crystal layer 202 is blocked by the left circular polarization filter. The red hologram image resulting from the process 203 becomes invisible. Here, if the back of the cholesteric liquid crystal layer 202 is colored, the window 102 is visible in that color. For example, if the back of the cholesteric liquid crystal layer 202 is dark, the window 102 looks similar dark.

(Function as an opening seal)
When the lid of the PET bottle or glass bottle is covered with the shrink film 100, when the lid is opened, at least one of the perforations 103a and 103b breaks, the shrink film 100 breaks, and the identification medium 200 also breaks. . Since the identification medium 200 that has been broken can be clearly confirmed, the trace of opening the lid remains clearly. That is, the shrink film 100 can function as an opening seal in which the fact of opening remains clearly as a trace.

  In addition, when opening a lid | cover from the state which shrink | contracted the shrink film 100 and coat | covers lid | covers, such as a bottle, the knob | pick part 104 is first picked up with a finger | toe and it pulls up in FIG. At this time, the perforations 103a and 103b are broken, and the shrink film 100 covering a lid such as a bottle can be removed.

(Reuse prevention function)
When the shrink film 100 is shrunk and the cover such as a bottle is covered, when the shrink film 100 is peeled off, at least one of the perforations 103a and 103b breaks, and the shrink film 100 breaks. The identification medium 200 is also broken. For this reason, reuse of the identification medium 200 is prevented.

(Superiority)
In observation using the left and right circular polarization filters, switching between the right circular polarization filter and the left circular polarization filter switches the presence / absence of observation of the hologram image, thereby making it possible to determine authenticity. At this time, since the optical characteristics of the shrink film 100 are adjusted so as not to disturb the polarization characteristics of the transmitted light, the switching of the hologram image is clearly observed, and a high identification function is obtained.

  If the optical properties of the shrink film 100 are not adjusted as described above, circularly polarized light changes to elliptically polarized light when transmitted through the shrink film 100 due to the birefringence effect. As a result, the switching of the visible state of the hologram image due to the switching of the left and right circularly polarizing filters is not clear, and the identification function is low. In addition, when the shrink film 100 has birefringence functioning as an (nλ / 2) plate as in the case of Embodiment 2 described later, since the turning direction of the circularly polarized light that is transmitted is only reversed, Switching of the visual state of the hologram image by switching of the circular polarization filter can be clearly obtained.

  When the shrink film 100 is shrunk and the bottle or the like is covered, if the shrink film 100 is forcibly peeled off, the perforations 103a and 103b are broken, and the identification medium 200 is broken. For this reason, unauthorized reuse of the identification medium 200 is prevented.

  For example, when the shrink film 100 is used as a cap seal of a bottle, it is possible to determine the authenticity of the bottle and its contents by the cap seal, and the function as an opening seal can prevent refilling of the contents.

2. Second Embodiment In this embodiment, in the first embodiment, in a state before the shrink film 100 is shrunk or in a shrunk state, it has birefringence that functions as an (nλ / 2) plate (n is an odd number). Set as follows. That is, the shrink film 100 is set so as to have an optical anisotropy in which the phase difference in the biaxial directions perpendicular to the transmitted light is shifted by (nλ / 2) in a state before shrinkage or in a shrinkage state. Others are the same as the first embodiment. In the present embodiment, the condition (1) in the first embodiment is adjusted so that the shrink film 100 has birefringence that functions as an (nλ / 2) plate in a state before shrinkage or in a shrinkage state. . In the following description, n in the description of (nλ / 2) plate is an odd number. Generally, n = 1 is selected as n, but other values (for example, n = 3 and n = 5) can be selected as long as it is an odd number.

(Identification function)
Here, a state where the shrinkable film of FIG. 1 is shrunk onto the beverage bottle and covered will be described. When the window 102 is directly observed in this state, red reflected light from the cholesteric liquid crystal layer 202 is observed, and a red hologram image resulting from the hologram processing 203 is observed.

  Here, the cholesteric liquid crystal layer 202 selectively reflects red right circularly polarized light, but this right circularly polarized light is transmitted through the shrink film 100 functioning as an (nλ / 2) plate, so that the turning direction is reversed, Left circularly polarized light. Therefore, when the window 102 is observed through the right circular polarization filter, the reflected light from the cholesteric liquid crystal layer 202 emitted from the window 102 is left circularly polarized light. Therefore, the reflected light is blocked by the right circular polarizing filter, and the hologram processing 203 is performed. The red hologram image due to the above cannot be seen. In this case, if the back of the cholesteric liquid crystal layer 202 is colored, the window 102 can be seen in that color. For example, if the back of the cholesteric liquid crystal layer 202 is dark, the window 102 looks similar dark.

  Further, when the window 102 is observed through the left circular polarizing filter, the reflected light from the cholesteric liquid crystal layer 202 that has been left circularly polarized by transmitting through the shrink film 100 is transmitted through the left circular polarizing filter. The red hologram image due to the image looks clearer than when directly viewed. That is, contrary to the case of the first embodiment, a switching characteristic is obtained in which the hologram image cannot be seen in the observation through the right circular polarization filter and the hologram image can be preferentially seen in the observation through the left circular polarization filter. .

  If the contracted film 100 in the contracted state is not in a state of functioning as an (nλ / 2) plate, and is not in a state that does not disturb the polarization state of transmitted light (that is, the state of the first embodiment). The red right circularly polarized light reflected from the cholesteric liquid crystal layer 202 passes through the shrink film 100 to become elliptically polarized light and can be observed with the left and right circularly polarized filters. In this case, the clear switching effect mentioned above cannot be observed, and the discriminability is lowered.

(Function as an opening seal)
This is the same as in the first embodiment.

(Reuse prevention function)
This is the same as in the first embodiment.

(Superiority)
This is the same as in the first embodiment.

3. Third Embodiment It is also possible to make the shrink film 100 function as an (nλ / 2) plate only by stretching for causing shrinkage. In this case, the stretching conditions are adjusted so that the refractive index anisotropy generated in the shrink film 100 is that of the (nλ / 2) plate in the stretching step while heating to cause shrinkage.

4). Others A printed pattern of ink may be formed so as to overlap with the hologram formed in the cholesteric liquid crystal layer. This printed pattern can be formed on a shrink film or a substrate film. The number of perforations is not limited to two and may be one or three or more. The part which covers a bottle etc. with a shrink film is not limited to the part of lids, such as a bottle, The part of the main body may be sufficient. Moreover, the object covered by the shrink film is not limited to a container filled with a liquid for beverages, and may be various foods and articles, various packages, and the like. The area of the printing layer 101 is not limited to that illustrated, and there may be a transparent portion other than the window 102. Further, a structure in which the printing layer 101 is not provided, the whole is transparent, and the identification medium 200 is attached to a part thereof is also possible. Moreover, it is also possible to comprise the shrink film 100 with the colored material in the range which can visually recognize the identification medium 200. Alternatively, an adhesive layer may be provided on the surface of the shrink film 100 that contacts the bottle, and the shrink film 100 may be fixed to the object by the function of the adhesive layer.

  In the embodiment, an example in which the shrink film shrinks in one direction has been shown. However, by stretching in multiple directions in the step of stretching while heating, the property of shrinking two-dimensionally at the time of reheating is imparted. It is also possible. In this case, the conditions of the step (1) described above are adjusted so as to obtain a characteristic or a (nλ / 2) plate that does not disturb the polarization state of transmitted light in a contracted state. In addition to the step (1), in addition to the step (1), the step (2) (or the step (2) is used as a characteristic or a (nλ / 2) plate that does not disturb the polarization state of transmitted light in a contracted state. Only) is also possible.

  As the optical functional layer, besides using a cholesteric liquid crystal layer, a structure in which a circularly polarizing filter and a light reflecting layer are stacked to selectively reflect circularly polarized light in a specific turning direction can be employed. It is also possible to dispose a reflective layer, a circularly polarizing filter layer, a multilayer thin film in which light-transmitting films having different refractive indexes are laminated in multiple layers, etc. below the cholesteric liquid crystal layer (non-observation surface side).

  The present invention can be used in a technique for determining authenticity.

DESCRIPTION OF SYMBOLS 100 ... Shrink film 101 ... Print layer 102 ... Window 103a ... Perforation 103b ... Perforation 104 ... Pick part 200 ... Identification medium 201 ... Base film 202 ... Cholesteric liquid crystal layer 203 ... Hologram processing 204 ... Transparent adhesive layer.

Claims (5)

At least a portion that covers at least a portion of the object by contraction has a transparent film,
An optical functional layer that selectively reflects circularly polarized light in a specific turning direction on the side of the at least part of the film that contacts the object;
The film has an optical characteristic that does not disturb a polarization state of transmitted light or an optical characteristic that functions as an (nλ / 2) plate (n is an odd number) in a state in which the film contracts and covers the object. Element.   The covering member according to claim 1, wherein the optical functional layer is a cholesteric liquid crystal layer.   The covering member according to claim 2, wherein the cholesteric liquid crystal layer is subjected to hologram processing.   The covering member according to claim 1, wherein perforations are formed in the film and the optical functional layer. The said film is extended | stretched in the direction orthogonal to the said direction to shrink | contract, The covering member as described in any one of Claims 1-4 characterized by the above-mentioned.

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