JP2020016706A - Reversible deformation lens film - Google Patents

Abstract

To provide a reversible deformation lens film which exhibits a visual effect without needing a change in angle viewed by an observer and movement of a sheet itself.SOLUTION: A reversible deformation lens film 1 includes a sheet-like matrix 10, and a convex lens assembly 20 that is provided on a first surface 10a of the matrix 10 and in which a plurality of convex lenses 21 are formed, at least one of the matrix 10 and the convex lens assembly 20 is formed of a resin that adsorbs and desorbs moisture, and at least one of a distance between an apex of the convex lens 21 and a second surface 10b of the matrix 10, a height of the convex lens 21, a width of the convex lens 21, a pitch of the convex lens 21, a refractive index of the matrix 10, a refractive index of the convex lens 21 and a radius of curvature of the convex lens 21 varies depending on a change in volume in response to adsorption and desorption.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reversible deformable lens film, and more particularly, to a reversible deformable lens film that reversibly deforms with the adsorption and desorption of a liquid.

  A microlens array is an optical element in which a large number of microlenses are formed on the same plane, and is used in a wide range of fields such as medical care, communication, and security.

  As an article using a microlens array, there is a stereoscopic sheet that allows a three-dimensional image to be visually recognized without using special glasses or the like. For example, on a transparent substrate, a convex lens assembly and a three-dimensional moiré pattern on the focal plane of the convex lens are provided, and when the pattern is viewed through the convex lens assembly, ups and downs of the three-dimensional moiré pattern are observed. There is known a stereoscopic sheet in which the appearance of a three-dimensional moiré pattern is changed by changing the viewing angle by observing (see Patent Documents 1 to 3).

JP 2008-12870 A Japanese Patent No. 4885101 JP 2012-88584 A

  In the stereoscopic sheets described in Patent Literatures 1 to 3, the appearance of the three-dimensional moiré pattern changes by moving the stereoscopic sheet itself or changing the angle at which the observer views. For this reason, there is a problem that, when the observation is continued from the same angle without moving the sheet, the appearance of the moire pattern does not change and the visual effect is small.

  Furthermore, in these stereoscopic sheets, the size of the three-dimensional moiré pattern can be continuously changed by changing the viewing angle of the observer, but the film thickness, refractive index, and lens curvature of the stereoscopic sheet do not change. And the focal position for the three-dimensional moiré pattern does not change. Therefore, there is a limit to the visual effect, and it is difficult to produce a switching effect in which a three-dimensional moiré pattern is visible or invisible.

  In view of the above circumstances, an object of the present invention is to provide a reversible deformable lens film that exhibits a visual effect without requiring a change in the angle of view of an observer or movement of a sheet itself.

  The present invention is a reversible deformable lens film including a sheet-shaped matrix and a convex lens assembly provided on a first surface of the matrix and having a plurality of convex lenses formed thereon. In this reversibly deformable lens film, at least one of the matrix and the convex lens aggregate is formed of a resin that adsorbs and desorbs moisture, and changes in volume due to adsorption and desorption, from the top of the convex lens to the second surface of the matrix. , The height of the convex lens, the width of the convex lens, the pitch of the convex lens, the refractive index of the matrix, the refractive index of the convex lens, and the radius of curvature of the convex lens change.

  The reversibly deformable lens film of the present invention exerts a visual effect without requiring a change in the viewing angle of the observer or movement of the sheet itself.

It is a schematic cross section of a reversible deformation lens film concerning a first embodiment of the present invention. It is a figure which shows the definition of the dimension of each part of the reversible deformation lens film. It is a figure showing the state where the same reversible deformation lens film absorbed moisture. It is a schematic cross section which shows the modification of the same reversible deformation lens film. It is a figure which shows the state which adsorb | sucks moisture in the same modification. It is a schematic cross section which shows the 2nd modification of the same reversible deformation lens film. It is a figure which shows the state which adsorb | sucks moisture in the 2nd modification. It is a schematic cross section of a reversible deformation lens film concerning a second embodiment of the present invention. It is a figure showing the state where the same reversible deformation lens film absorbed moisture. It is a figure showing the state where the modification of the reversible deformation lens film adsorbed moisture. It is a figure for explaining the design concept of the reversible deformation lens film of the present invention.

A reversible deformable lens film (hereinafter, may be simply referred to as a “lens film”) according to the first embodiment of the present invention will be described with reference to FIGS.
In the present specification, “water” may be any of a gas, a liquid, and a solid (gas phase, liquid phase, solid phase). For example, in the case of water, it may be any of water vapor, droplets, and ice. You may. Moisture may include other substances as well as alone. For example, another component (for example, a fragrance component) may be mixed with steam. Further, a substance having a hydroxyl group (OH group) in a water molecule, for example, alcohols is also included in the “water” in the present invention.

  FIG. 1 is a schematic sectional view showing a lens film 1 of the present embodiment. As shown in FIG. 1, the lens film 1 includes a matrix 10 in a sheet shape, and a convex lens assembly 20 formed on the matrix 10.

  The matrix 10 has a flat first surface 10a and a flat second surface 10b on both sides in the thickness direction. The convex lens assembly 20 is formed on the first surface 10a of the matrix 10.

  The matrix 10 is formed of a material that absorbs and desorbs moisture and changes its volume as it is absorbed and desorbed. Examples of such a material include a hydrophilic polymer-based material having a carboxyl group, an aldehyde group, a hydroxyl group, an amino group, an amide group, a sulfone group, or the like, which is a hydrophilic group. A plurality of hydrophilic polymer-based materials may be mixed.

  Examples of the hydrophilic polymer-based material include polyacrylic acid-based, polymaleic acid-based, polyvinyl alcohol-based, polyvinylpyrrolidone-based, polyvinylpyridine-based, polyacrylamide-based, polyethylene oxide-based, and polyvinyl sulfone-based materials. Further, a mixture composed of two or more of these material systems incorporated in a main chain or a side chain may be used. Specific examples include a copolymer of polyacrylic acid and polyvinyl alcohol, and a copolymer of polyacrylic acid and polymaleic acid.

  Alternatively, a gel material can be used. Specifically, a double network gel in which two types of hydrophilic polymer chains form an interpenetrating polymer network to increase strength, and a nanocomposite gel in which clay, a clay compound, acts as a physical crosslinking point Can be exemplified.

The various materials described above may include a curable resin material. By using a curable resin material, the above-described materials can be formed into various three-dimensional structures. Further, since the crosslinking density can be controlled by changing the curing conditions, the volume change rate of the formed structure due to the absorption and desorption of moisture can be controlled.
Examples of the curable resin material include ionizing radiation-curable organic monomers, oligomers, polymers, and thermosetting resins.

The ionizing radiation-curable organic monomers, oligomers and polymers are cured through a crosslinking reaction by irradiation with active energy rays such as ultraviolet rays and electron beams.
Ionizing radiation-curable monomers and oligomers applicable to the present invention include acrylamide, N-methylacrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminopropyl Acrylamide various quaternary salts, acryloylmorpholine, N, N-dimethylaminoethyl acrylate various quaternary salts, acrylic acid, various alkyl acrylates, methacrylic acid, various alkyl methacrylates, 2-hydroxyethyl methacrylate, glycerol monomethacrylate, N-vinyl pyrrolidone , Acrylonitrile, styrene, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, triacrylate Propylene glycol diacrylate, polypropylene glycol diacrylate, 2,2-bis [4- (acryloxydiethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, 2-hydroxy- 1-acryloxy-3-methacryloxypropane, 2,2-bis [4- (acryloxypolypropoxy) phenyl] propane, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1, 3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2-hydride Xy-1,3-dimethacryloxypropane, 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxyethoxydiethoxy) phenyl] propane, 2,2 -Bis [4- (methacryloxyethoxypolyethoxy) phenyl] propane, trimethylolpropane trimethacrylate, tetramethylolmethane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethane triacrylate, tetramethylolmethanetetraacrylate, dipentaerythritol hexa Examples include acrylate, N, N'-methylenebisacrylamide, N, N'-methylenebismethacrylamide, diethylene glycol diallyl ether, and divinylbenzene.

  As the thermosetting resin, a resin containing an unsaturated polyester resin or an epoxy resin as a main component is preferable. For example, an unsaturated polyester resin, a reactive diluent having a hydroxyl group and a carbon-carbon double bond, a resin composition containing a polymerization initiator as an essential component, a liquid bisphenol-type epoxy resin, a hydroxyl group and a carbon-carbon Examples thereof include a resin composition containing a phenol resin curing agent having a double bond and a curing accelerator.

The hydrophilic polymer-based material or the gel material may contain a crosslinking agent, a filler, and the like.
As the crosslinking agent, a compound having two or more polymerizable functional groups can be used, and ethylene glycol, propylene glycol, trimethylolpropane, glycerin, polyoxyethylene glycol, polyoxypropylene glycol, polyglycerin, N, N ′ -Methylenebisacrylamide, N, N-methylene-bis-N-vinylacetamide, N, N-butylene-bis-N-vinylacetamide, tolylene diisocyanate, hexamethylene diisocyanate, allylated starch, allylated cellulose, diallyl phthalate, Examples thereof include tetraallyloxyethane, pentaerythritol triallyl ether, trimethylolpropane triallyl ether, diethylene glycol diallyl ether, and triallyl trimellitate.

The shape of the filler is not particularly limited, and examples thereof include a sphere, a particle, a needle, a fiber, a plate, a scale, a rod, and an irregular shape.
Fillers having a hydrophilic surface are preferred from the viewpoint of compatibility. Examples of the particulate filler having a hydrophilic surface include metal oxide fine particles, metal fine particles, zeolite, and polymer fine particles that have been subjected to a hydrophilic treatment. Examples of the plate-like filler having a hydrophilic surface include water-swellable layered clay compounds such as saponite, stevennite, hectorite, montmorillonite, lucentite, and somasif. Examples of the fibrous filler having a hydrophilic surface include cellulose nanofibers, hydrophilically treated carbon nanotubes, and glass fillers.

  For the hydrophilic polymer material or the gel material, a polymerization initiator can be appropriately selected depending on the polymerization mode. Specific examples of the polymerization initiator include hydrogen peroxide, persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate, and azo-based initiators such as 2,2′-azobis (2-amidinopropane). Dihydrochloride, 2,2'-azobis (N, N'-dimethyleneisobutylamidine) dihydrochloride, 2,2'-azobis {2-methyl-N- [1,1, -bis (hydroxymethyl)- 2-hydroxyethyl] propionamide {, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 4,4'-azobis (4-cyanovaleric acid), 2,2 '-Azobisisobutyronitrile, 2,2'-azobis (2,4'-dimethylvaleronitrile), benzophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy Cyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphonic oxide, 1- [4- (2-hydroxyethoxy) -phenyl] -2- Compounds which generate radicals by ultraviolet light such as hydroxy-2-methyl-1-propan-1-one, 2,4-diethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino -2-hydroxypropoxy) -3,4-dimethyl-9H-thioxanthone-9-one mesochloride, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropane-1, 2-benzyl-2- Dimethylamino-1- (4-morpholinophenyl) -butanone 1, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyr-1-yl) titanium, 1,3-di (t-butylperoxycarbonyl) benzene, 3,3 ′, 4, Compounds that generate radicals by light having a wavelength of 360 nm or more, such as a substance obtained by mixing a thiopyrylium salt, merocyanine, quinoline, and stilquinoline dye with a peroxyester such as 4'-tetra- (t-butylperoxycarbonyl) benzophenone Hydrogen peroxide or persulfate can be used as a redox initiator by combining a reducing substance such as sulfite or L-ascorbic acid or an amine salt.

The convex lens assembly 20 has a plurality of convex lenses 21 having the same shape and the same size, which are regularly arranged at predetermined intervals. The convex lens assembly is formed of a resin that does not absorb or desorb moisture, or a resin that absorbs or desorbs moisture but does not substantially change the volume due to absorption and desorption (non-deformable resin). .
Examples of the non-deformable resin include polyethylene terephthalate (PET) and polycarbonate (PC).

The manufacturing procedure of the lens film 1 will be described.
First, the matrix 10 is formed. The matrix 10 can be formed by a solution casting method. The solution casting method includes bar coating, dip coating, spin coating, flow coating, spray coating, roll coating, gravure roll coating, air doctor coating, plaid coating, wire doctor coating, Examples include knife coating, reverse coating, transfer roll coating, microgravure coating, kiss coating, cast coating, slot orifice coating, calendar coating, and die coating.

A solvent is added as necessary to a material appropriately selected from the above-mentioned hydrophilic polymer-based materials and gel materials to prepare a coating liquid for forming a matrix.
Next, the prepared coating liquid for forming a matrix is applied on a transparent substrate. As the transparent substrate, a film made of polyethylene terephthalate (PET) or polycarbonate (PC) can be used. The transparent substrate is not particularly limited as long as it is not deformed in a step such as a heat treatment step and an ionizing radiation irradiation step performed after the application of the coating liquid. Further, as for the transparent substrate, a substrate that can easily peel the formed matrix is preferable.

Subsequently, the applied coating liquid is dried by heat treatment to remove the solvent in the coating liquid and form a coating film. For the heat treatment, known drying means can be appropriately employed. For example, heating, blowing, hot air, or the like can be used as the drying means.
The matrix 10 is formed by the above procedure.

  Next, the convex lens assembly 20 is formed on the matrix 10 using a non-deformable resin. The convex lens assembly 20 can be formed by a known method. For example, the convex lens assembly 20 may be formed by pressing a nanoimprint or a roll-shaped lens mold against the matrix 10.

When the matrix 10 or the convex lens assembly 20 is formed of an ionizing radiation curable resin, ionizing radiation is applied as necessary.
As the ionizing radiation, ultraviolet rays, electron beams and the like can be used. In the case of ultraviolet curing, light sources such as a high-pressure mercury lamp, a low-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a carbon arc, and a xenon arc can be used. As irradiation conditions of the ultraviolet rays, irradiation intensity of 100 to 500 mW / cm ² is suitable, and irradiation amount is preferably 200 mJ / cm ² or more from the viewpoint of obtaining sufficient intensity.
In the case of electron beam curing, use electron beams emitted from various electron beam accelerators such as Cockloft-Wald type, Bande graph type, Resonant transformer type, Insulated core transformer type, Linear type, Dynamitron type, High frequency type Can be. The electron beam preferably has an energy of about 50 KeV to about 1000 KeV, and more preferably an electron beam having an energy of about 100 KeV to about 300 KeV.
Finally, when the transparent substrate is removed from the matrix 10, the lens film 1 of the present embodiment is completed.

The operation when using the lens film 1 will be described.
In the lens film 1, various parameters such as a lens height a, a lens width b, a lens pitch c, a maximum thickness d, and a radius of curvature e shown in FIG. Is set to the value of
The convex lens in the present invention may not be a perfect sphere before or after moisture adsorption, but in this case, a value of a radius of curvature calculated by approximating a sphere having approximately the same size is adopted.

  When the humidity around the lens film 1 becomes high or when the lens film 1 is sprayed with water to make it wet, the matrix 10 absorbs the surrounding moisture. As a result, the matrix 10 expands isotropically and increases in volume, as shown in FIG. On the other hand, since the convex lens assembly 20 is formed of a non-deformable resin, it maintains a state in which it is not substantially deformed.

Due to the increase in the volume of the matrix 10, the lens pitch c and the maximum thickness d of the lens film 1 are changed from the normal values. Depending on the material of the matrix 10, the refractive index of the matrix 10 also changes. As a result, the image forming position of each convex lens 21 of the convex lens assembly 20 changes in the thickness direction and / or the surface direction of the lens film 1, and the appearance of what is located on the second surface 10 b side of the matrix 10 changes the moire effect. It changes with.
That is, in the lens film 1, a visual effect is generated by the matrix 10 absorbing moisture. This visual effect may be approximately in two stages, that is, at the time of adsorbing moisture and at the time of non-adsorbing, or may change continuously as the amount of adsorbed moisture changes.

  When the humidity around the lens film 1 decreases or the temperature rises, the matrix 10 releases the adsorbed moisture and decreases in volume. Eventually, the matrix 10 will have normal dimensions and volumes, and the various parameters will also return to their normal values.

  As described above, according to the lens film 1 of the present embodiment, since the matrix 10 absorbs and desorbs moisture to produce a visual effect, the observer can change the viewing angle or move the lens film 1. The visual effect can be exhibited without doing so.

In the above description, an example in which only the matrix changes in volume has been described, but the lens film of the present embodiment is not limited to this.
The lens film 1A of the modification shown in FIG. 4 is an example of a configuration in which only the convex lens assembly changes in volume. The convex lens assembly 20A is formed of the same material as the matrix 10, and the matrix 10A is formed of a non-deformable resin.
FIG. 5 shows a state in which the lens film 1A has absorbed moisture. The convex lens aggregate 20A expands by adsorbing moisture, but the bottom surface of the convex lens aggregate 20A joined to the matrix 10A is restricted by the matrix 10A, so that the value of the lens width b substantially changes. do not do. As a result, the convex lens assembly expands upward as shown in FIG. 5, and the lens height a and the maximum thickness d change.

The lens film 1B of the second modification shown in FIG. 6 is an example of a configuration in which both the convex lens assembly and the matrix change in volume. The lens film 1B includes a matrix 10 and a convex lens assembly 20A.
FIG. 7 shows a state in which the lens film 1B has absorbed moisture. In the lens film 1B, since the matrix 10 and the convex lens aggregate 20A expand by absorbing moisture, when the convex lens aggregate 20A expands, the lens width b also increases. As a result, in the lens film 1B, all of the lens height a, the lens width b, the lens pitch c, and the maximum thickness d change as compared with the normal state. However, the degree of change may not be completely parallel.

The manner of expansion of the matrix and the convex lens assembly during moisture adsorption can be controlled by various methods. Therefore, the expansion mode can be appropriately adjusted depending on the application, the desired visual effect mode, and the like.
For example, when the addition rate of the crosslinking agent is increased, the crosslinking density of the matrix and the convex lens assembly increases, and the volume change rate (expansion rate) decreases. Further, by increasing the amount of the resin or monomer component having high hydrophilicity, the water absorption of the matrix and the convex lens assembly increases, and the volume change rate increases.

  In addition, it is also possible to control the expansion mode by changing the degree of curing or the degree of polymerization. For example, there is a method of changing the activation rate of the initiator at the time of curing the coating liquid. When the activation rate of the initiator decreases, the points of occurrence of the polymerization reaction and the cross-linking reaction decrease, so that the cross-link density, the degree of curing and the degree of polymerization decrease. As a result, a portion having a high volume deformation rate and a portion having a low volume deformation rate are generated inside the matrix or the convex lens assembly, and an anisotropic volume change can be induced. As a method of changing the initiator activation rate, for example, when using an ultraviolet curable resin, using an ultraviolet shielding mask, a method of providing a distribution in the coating film with respect to the amount and illuminance of ultraviolet irradiation, and a method of irradiating ultraviolet light There is a method of giving a distribution to the activation rate of the initiator by utilizing the decay of the ultraviolet intensity inside the coating film at the time.

  A second embodiment of the present invention will be described with reference to FIGS. In the following description, the same components as those already described are denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 8 is a schematic sectional view showing the lens film 51 of the present embodiment. In the lens film 51, the matrix 10 and the convex lens assembly 20 are the same as in the first embodiment. In the lens film 51, the constraining layer 52 is disposed on the second surface 10b opposite to the first surface 10a in the matrix 10. The constraining layer 52 is joined to the matrix 10.

The constraining layer 52 is formed of a material that does not adsorb moisture or a material that does not substantially change in volume even when adsorbing moisture. Examples of the material of the constraining layer 52 include transparent materials such as the non-deformable resin and glass described above, and examples of the opaque material include various metals and wood, paper, and ceramics whose moisture absorption is suppressed by surface treatment. it can.
Whether the constraining layer is made transparent or opaque can be appropriately determined in consideration of the use and the like. When a predetermined pattern has a visual effect, if a predetermined printing pattern is provided between the constraining layer and the matrix, the constraining layer may be opaque. When the lens film is attached to an arbitrary article to produce a visual effect on an object below the lens film, the constraining layer may be made transparent. In this case, the constraining layer may be colorless or colored.

  Since the lens film 51 of the present embodiment includes the constraining layer 52, when the matrix 10 expands by adsorbing moisture, the increase in dimension in the plane direction is constrained by the constraining layer 52. As a result, the matrix 10 expands substantially only in the thickness direction as shown in FIG. 9, and only the maximum thickness d changes while the lens pitch c remains unchanged.

Also in the lens film 51 of the present embodiment, as in the first embodiment, a visual effect can be exerted without changing the viewing angle of the observer or moving the lens film 1.
Further, the deformation behavior of the matrix 10 is controlled by the constraining layer 52, so that a desired visual effect can be easily realized.

The structure of the present embodiment may be applied to the lens film 1A of the above-described modified example and the lens film 1B of the second modified example.
When the constraining layer 52 is combined with the lens film 1A, the expansion mode of the lens film 1A hardly changes. However, by appropriately setting the thickness of the constraining layer 52, it is easy to adjust the focal length between normal time and expansion time. Become.

FIG. 10 shows an expanded shape when the constraining layer 52 is combined with the lens film 1B. Since the constraining layer 52 suppresses an increase in the dimensions of the matrix 10 and the convex lens assembly 20A in the plane direction, the convex lens assembly 20A strongly expands upward.
As described above, by appropriately combining the constraining layers 52, the shapes of the matrix and the convex lens assembly at the time of adsorbing moisture can be variously and easily changed.

  The present invention will be further described with reference to examples. The present invention is not limited at all by the contents of the examples.

(Example 1)
Hydrophilic UV-curable resin UA-W2A (Shin-Nakamura Chemical Co., Ltd., 6 parts by mass), hydrophilic UV-curable monomer HEAA (KJ Chemicals, 41 parts by mass), water-swellable layered clay mineral LAPONITE RDS (BYK Co., Ltd., 3 parts by mass), a photopolymerization initiator Irgacure 2959 (manufactured by BASF, 0.1 part by weight, external addition) and pure water (50 parts by mass) as a solvent were mixed to prepare a coating solution.

This coating liquid was applied on a substrate. Polyethylene terephthalate (PET) (Lumilar T60, thickness 75 μm, manufactured by Toray Industries, Inc.) was selected as the substrate. The application of the coating liquid was performed so that the dry film thickness was 26 μm.
The coated substrate was heat-treated and the coating liquid was dried to form a coating film on the substrate. The heat treatment was performed at 105 ° C. for 1 minute.

Next, the silicone plate with the convex lens shape was pressed against the coating film to support the coating film between the substrate and the silicone plate.
In this state, the coating film was irradiated with ultraviolet rays to cure the coating film. Irradiation with ultraviolet rays was performed at an exposure amount of 420 mJ / cm ² using a conveyor type ultraviolet curing device. The silicone plate was peeled off, and a convex lens assembly was formed on the first surface of the matrix, and the lens film of Example 1 including the constraining layer on the second surface was produced. The lens film of Example 1 is configured so that both the matrix and the convex lens assembly can adsorb moisture.
That is, the matrix and the convex lens assembly in the example correspond to the matrix 10 and the convex lens assembly 20A, respectively, and the base material (PET) corresponds to the constraining layer 25.

(Example 2)
A lens film of Example 2 was produced in the same procedure as in Example 1, except that the composition of the coating solution was changed as follows.
UA-W2A 18 parts by mass,
HEAA 29 parts by weight LAPONITE RDS 3 parts by weight Pure water 50 parts by weight Irgacure 2959 0.1 parts by weight, externally added

(Example 3)
A lens film of Example 3 was produced in the same procedure as in Example 1, except that the composition of the coating solution was changed as follows.
UA-W2A 30 parts by mass,
HEAA 17 parts by weight LAPONITE RDS 3 parts by weight Pure water 50 parts by weight Irgacure 2959 0.1 parts by weight, external addition

(Example 4)
A lens film of Example 4 was produced in the same procedure as in Example 1, except that the composition of the coating solution was changed as follows.
UA-W2A 42 parts by mass,
HEAA 5 parts by weight LAPONITE RDS 3 parts by weight Pure water 50 parts by weight Irgacure 2959 0.1 parts by weight, external addition

  Table 1 shows the dimensions of each part of the lens film of each example during normal operation and when adsorbing moisture. Normal conditions are room temperature of 22.7 ° C. and relative humidity of 27%. Water adsorption was performed by dropping water directly on the lens film and wiping off excess water after 3 minutes.

  In each of the examples, the lens height was greatly increased at the time of adsorbing moisture, and the rate of increase was changed depending on the composition of the coating liquid. On the other hand, the change in the lens width was slight, and the lens pitch was almost unchanged. When the moisture-absorbed lens film was dried, the dimensions of the respective parts returned to the same values as in normal times, and it was confirmed that the deformation due to the moisture adsorption was reversible.

  Table 2 shows the change over time in the refractive index of the matrix after moisture adsorption in the lens films of the examples. Although the refractive index decreased in any of the examples due to moisture adsorption, the refractive index gradually increased with the passage of time, and returned to almost the normal value in 150 seconds.

Table 3 shows the refractive index before and after moisture adsorption, the radius of curvature of the convex lens, the focal length of the convex lens, and the focal distance before and after wetting in the lens films of the examples. The focal length f was calculated based on the radius of curvature R and the refractive index n using the formula f = R / (n-1) for the focal length of the plano-convex lens.
In each of the examples, the radius of curvature of the convex lens was reduced after moisture adsorption, and the focal length was reduced accordingly. The focal distance before and after the adsorption of moisture changed depending on the composition of the coating liquid. In particular, in Examples 1 and 2, a switching visual effect was realized in which the print pattern adhered to the second surface became visible due to moisture adsorption from a state where it was not normally visible. Each parameter of the convex lens assembly returned to the normal value by drying, and reproducible results were obtained even when moisture was adsorbed again.

Next, an example of parameter setting in the present invention will be described using an embodiment.
For example, in order to obtain a switching effect in the lens film of the present invention, parameters are set such that the focal point of the convex lens coincides with the print pattern in one of the normal state and the time of moisture adsorption, and the focal point of the convex lens is largely apart from the print pattern in the other. do it. FIG. 11 shows an example in which the focal point F of the convex lens 21A is far away from the print pattern (pattern) 60 in a normal state, and the focal point of the convex lens 21A coincides with the print pattern 60 during moisture adsorption. In this case, the print pattern 60 can be visually recognized only when the lens film adsorbs moisture. If this relationship is reversed, the print pattern 60 can be eliminated when the lens film absorbs moisture. FIG. 11 shows only one lens for convenience of explanation.
Hereinafter, in the fifth embodiment, a design example for realizing the switching effect as shown in FIG. 11 will be described.

(Example 5)
A coating film having a thickness of 96 μm was formed on a PET substrate having a thickness of 50 μm using the coating liquid of Example 2. Using the silicone plate of Example 1 on this coating film, a matrix and a convex lens assembly having the same dimensions as Examples 1 to 4 were formed. A printing pattern was formed on the surface (lower surface) of the PET substrate opposite to the surface on which the matrix and the convex lens assembly were formed.

With respect to the lens film of Example 5, the distance from the top of the convex lens to the print pattern on the lower surface side of the constraining layer was measured using a contact type film thickness meter Digimicro MC-101 manufactured by Nikon Corporation. At the time of moisture adsorption.
The behavior of the convex lens was the same as in Example 2, and the focal length during normal operation was 462 μm, and the focal length during moisture adsorption was 332 μm.
The difference between the focal length and the distance from the vertex of the convex lens to the printing pattern was 316 μm at normal time and 44 μm at moisture adsorption.

When the lens film of Example 5 was viewed from the convex lens assembly side, the printed pattern could not be visually recognized in a normal state, but the printed pattern appeared visually after the wet treatment. When the lens film dried, the printed pattern disappeared.
Thus, in the lens film of the present invention, it was confirmed that various visual effects including a switching effect can be produced by appropriately setting the parameters of the convex lens assembly and the matrix.

  As described above, each embodiment and example of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and a change in the configuration without departing from the gist of the present invention, Combinations are also included.

  For example, when a printing pattern is provided on the lens film, one may be provided on the second surface of the matrix, the other on the lower surface of the constraining layer, and so on at two different places in the thickness direction. In this case, by designing the convex lens focal point at the normal time and the convex lens focal point at the time of moisture adsorption to be located in the vicinity of the respective print patterns, different patterns between the normal time and the time of moisture adsorption can be visually recognized. Visual effects can be realized.

Further, the convex lens assembly may include a plurality of types of convex lenses having different parameters.
The pattern to be subjected to the visual effect may be provided by a method other than printing.

1, 1A, 1B, 51 Reversible deformable lens film 10, 10A Matrix 10a First surface 10b Second surface 20, 20A Convex lens assembly 21, 21A Convex lens 52 Restriction layer 60 Printing pattern (pattern)

Claims (5)

A sheet matrix,
A convex lens assembly provided on the first surface of the matrix and having a plurality of convex lenses formed thereon,
With
At least one of the matrix and the convex lens assembly is formed of a resin that adsorbs and desorbs moisture, and a distance from a vertex of the convex lens to a second surface of the matrix due to a volume change caused by the adsorption and desorption. At least one of the height of the convex lens, the width of the convex lens, the pitch of the convex lens, the refractive index of the matrix, the refractive index of the convex lens, and the radius of curvature of the convex lens changes.
Reversible deformation lens film. The resin is a polymer or copolymer of a curable resin material,
The reversibly deformable lens film according to claim 1. The curable resin material has ionizing radiation curable or thermosetting,
The reversibly deformable lens film according to claim 2. Further comprising a pattern disposed on the second surface of the matrix,
Moiré effect occurs in the pattern due to the volume change,
The reversible deformable lens film according to claim 1.   2. The reversibly deformable lens film according to claim 1, further comprising a constraining layer disposed in close contact with the second surface of the matrix and constraining deformation of the matrix due to the volume change. 3.

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