JP2008221644A - Pattern printing transparent sheet - Google Patents

Abstract

A highly transparent pattern-printed transparent sheet in which the reflection wavelength peak position does not shift to the visible light region is provided.
A pattern-printed transparent sheet in which a transparent pattern having a non-visible light reflectivity is printed on the surface of a transparent substrate, and a transparent layer is laminated on the printing surface of the transparent pattern, the transparent layer being ( A pattern-printed transparent sheet comprising a meth) acrylate resin composition and having a glass transition point (Tg) of 100 ° C. or higher.
[Selection] Figure 1

Description

  The present invention can be applied to a data input system for inputting to a screen of a medium, and is a member that provides a coordinate detection means that is lightweight, inexpensive, easy to increase in area, and capable of mass production. The present invention relates to a highly pattern-patterned transparent sheet.

  In recent years, there is an increasing need to convert handwritten characters, pictures, and the like into electronic data that can be handled by an information processing apparatus. Correspondingly, for example, as position information for indicating the position of the input locus, it is conceivable to combine information printed with a pattern reflecting infrared rays or ultraviolet rays which are invisible rays.

By the way, conventionally, films that reflect invisible light are known.
For example, Patent Document 1 discloses a reflective color filter structure for a liquid crystal display device that reproduces colors by reflection. Here, in the red light reflection color filter, as a means for increasing only the reflectance of the red light in the oblique direction without increasing the reflectance of the red light in the vertical direction more than necessary, the red color in the vertical direction is used. A reflective filter structure is further disclosed that further includes a first region that reflects light and a second region that reflects infrared light (invisible light) in the vertical direction. In such a structure, the second region reflects infrared rays in the vertical direction, so that there is no increase in red light reflectance in the vertical direction. In addition, since the selective reflection wavelength is shortened with respect to the light incident in the oblique direction, the red light is reflected with respect to the oblique incident light, and this object is achieved. Patent Documents 2 and 3 disclose a diffraction grating using a liquid crystalline film, a circularly polarizing plate, an optical filter, a colored decorative material, and the like.
However, none of these demands a coordinate input application, nor does it suggest a pattern-printed transparent sheet that can be used for a coordinate input application.

JP-T-2004-519728 International Application Publication WO99 / 034242 Pamphlet JP 2006-154865 A

As a result of various studies to obtain a highly transparent non-visible light reflective pattern-printed transparent sheet suitable for applications such as coordinate input of an image display device, the present inventors have paid attention to the following phenomenon.
(1) First, a configuration in which a cholesteric liquid crystal that is transparent to visible light and selectively reflects non-visible light such as infrared rays is printed on a transparent substrate in a dot shape and solidified by a crosslinking reaction. Was invented (Japanese Patent Application No. 2006-269920). However, in such a sheet, although the printed pattern is substantially transparent in the visible region, the pattern printed on the transparent substrate is completely invisible due to the lens effect due to the difference in refractive index between the pattern and the air interface. However, when fine irregularities are generated on the pattern surface, light scattering occurs due to the difference in refractive index from the air interface, and the pattern on the transparent substrate may appear a little whitish.
(2) Therefore, a process of completely transparent the appearance was considered by coating and forming a transparent layer having a refractive index close to that of the constituent material of the pattern so as to fill the gap between the patterns (Japanese Patent Application 2006). -179302). However, depending on the type of the transparent layer, when the transparent layer is applied and formed, the material of the transparent layer in the liquid state (or a diluent thereof) penetrates into the cholesteric liquid crystal of the printed pattern, and the multilayer structure of the cholesteric liquid crystal Changes as the layer swells, and the distance between the multilayer films (Bragg reflecting surfaces) shifts (shifts), which shifts the selective reflection wavelength peak position to the visible light region, resulting in transparent pattern printing. A new problem has been found that the problem of coloring the sheet occurs. In addition, since the base of the reflection wavelength is in the visible region, the pattern appears to be tinted, and moire occurs when a film is attached to the front surface of the display. Furthermore, the shift of the wavelength selection wavelength also changes over time due to fluctuations in the distance between the multi-layer films due to movement of the material molecules entering the multi-layer films over time, volatilization and escape. Furthermore, it has been found that the degree of change varies depending on the atmospheric temperature during the change over time.
(3) Therefore, it is found that preventing the reflection wavelength peak position from shifting to the visible light region is an important issue in order to obtain a highly transparent pattern-printed transparent sheet formed by forming a transparent layer. It came to do.
That is, the problem to be solved by the present invention is to provide a highly transparent pattern printed transparent sheet in which the reflection wavelength peak position does not shift to the visible light region.

As a result of intensive research to solve the above problems, the present inventors have made the glass transition point (Tg) of the transparent layer laminated on the transparent pattern printing surface of the pattern printing transparent sheet a specific range. The present invention has been completed by finding that the above problem can be solved.
That is, the present invention is a pattern-printed transparent sheet in which a non-visible light reflective transparent pattern is printed on the surface of a transparent substrate, and a transparent layer is laminated on the transparent pattern printing surface, the transparent layer It comprises a (meth) acrylate resin composition and has a glass transition point (Tg) of 100 ° C. or higher.

  According to the present invention, it is possible to provide a highly transparent pattern printed transparent sheet in which the reflection wavelength peak position does not shift to the visible light region.

The pattern-printed transparent sheet of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing one embodiment of the pattern-printed transparent sheet of the present invention.
As shown in FIG. 1, the pattern-printed transparent sheet 1 (hereinafter also simply referred to as transparent sheet 1) of the present invention has a transparent pattern 3 (hereinafter also simply referred to as transparent pattern 3) having a non-visible light reflective property on the surface of a transparent substrate 2. And the transparent layer 4 is laminated on the printing surface of the transparent pattern 3.

In the present invention, the wavelength of invisible light may be outside the range of the visible light region, and is not particularly limited. The point is that the reflected light in the transparent pattern is colored and visually recognized and does not stand out. Usually, infrared rays or ultraviolet rays are used. Infrared rays are usually preferably used in the near infrared region of 800 to 2500 nm, and particularly preferably used in the ultraviolet ray, particularly in the near ultraviolet region of 200 to 380 nm.
The following description will be made with a focus on near infrared rays of 800 to 2500 nm and near ultraviolet rays of 200 to 380 nm. Incidentally, in this specification, visible light is a visible wavelength region, and is 380-780 nm. Transparent means that the transmittance in the visible light region is high, specifically, the transmittance in the visible light region is about 50% or more, more preferably 70% or more.

The transparent sheet 1 of the present invention is characterized in that the transparent layer 4 is made of a (meth) acrylate resin composition, and the glass transition point (Tg) is 100 ° C. or higher. As will be described later, the reflection wavelength peak position is shifted (shifted) to the visible light region by applying the transparent layer 4 and setting the glass transition point (Tg) as a coating film after curing to 100 ° C. or more. ) Can be prevented.
The transparent layer 4 is caused by refracting or reflecting light caused by a difference in refractive index between the transparent pattern 3 and air, so that the transparent pattern is visually observed or moire fringes are generated due to interference with the image of the image display device. It is a layer for eliminating problems that occur. Therefore, the refractive index of the transparent layer is preferably as close as possible to the refractive index of the transparent pattern. Preferably, the material of the transparent layer is selected so that the refractive index difference between them is 0.14 or less. In addition to this, the transparent layer is a surface protective layer of the transparent pattern 3 for giving strength that can withstand repeated contact with the input terminal, for example, when inputting by hand with an input terminal such as a pen type. Also works.
Therefore, for this purpose, the transparent layer 4 is preferably formed thicker than the transparent pattern 3 so as to cover the transparent pattern 3, and the printing thickness is usually about 3 to 30 μm, preferably about 5 to 25 μm. is there.

Among the above-described infrared rays, in particular, near infrared rays in the near infrared region of 800 to 2500 nm, the reading range of an infrared sensor is generally 800 to 900 nm, and the best sensitivity of the sensor is 850 nm. Accordingly, it is required from the dot-shaped reflective transparent pattern that the reflection peak is within this range, and the peak center position is more preferably 850 nm. Even if the initial peak center position is 850 nm, if the peak position is shifted to the visible region side by 50 nm or more due to the change over time, most of the reflected light from the dots falls outside the sensor reading range. Therefore, accurate position information cannot be recognized. From the above, the spectral shift is preferably within 50 nm, preferably within 40 nm.
Therefore, as a method of suppressing the reflection wavelength shift of the transparent pattern when the transparent layer is formed by coating or the like, the transparent layer 4 is difficult to penetrate between layers of the cholesteric structure of the transparent pattern 3 composed of cholesteric liquid crystal. It is preferable to select a resin composition having a high glass transition point (Tg) in the coating state. In particular, the glass transition point (Tg) is preferably 100 ° C. or higher, and is a transparent body of a material having a refractive index close to that of the transparent pattern 3 in order to reduce moire, and has a glass transition point (Tg). ) At 100 ° C. or higher, it is desirable to use a (meth) acrylate resin composition as the transparent layer 4.
In order to increase the refractive index, metal oxide fine particles having a high refractive index such as zirconium oxide, zinc oxide, titanium oxide, aluminum oxide, and tin oxide may be mixed in the transparent layer 4.
Note that “difficult to change over time” means, for example, that when subjected to an accelerated test of change over time at 80 ° C., the spectral shift after 500 hours is within 50 nm.

Examples of (meth) acrylates include polyfunctional (meth) acrylate monomers and / or polyfunctional (meth) acrylate oligomers. These are one or two or more monomers only, one or two or more oligomers, or one or two or more monomers and one or two or more monomer oligomers. The composition is constituted as a mixed system of Such a composition is typically used as a photocurable (meth) acrylate resin composition containing a photopolymerization initiator. Further, it may be an electron beam curable (meth) acrylate resin or (meth) acrylate resin composition that does not contain a photopolymerization initiator.
Here, (meth) acrylate refers to acrylate or methacrylate.

  Examples of the polyfunctional (meth) acrylate monomer include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,6-hexanediol diene. (Meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (Meth) acrylate, ethylene oxide-modified phosphoric acid di (meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylate , Ethylene oxide modified trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (Meth) acrylate, tris (acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, caprolactone modified dipenta Examples include erythritol hexa (meth) acrylate.

Examples of polyfunctional (meth) acrylate oligomers include epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, polyether (meth) acrylate oligomers, and silicon (meth) acrylates. Can be mentioned.
Examples of the photopolymerization initiator include bisacylphosphine oxide-based, α-aminoketone-based and α-hydroxyketone photopolymerization initiators. Specific examples of the bisacylphosphine oxide photopolymerization initiator include diphenyl- (2,4,6-trimethylbenzoyl) phosphine oxide and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide. It is done. Specific examples of α-aminoketone photopolymerization initiators include 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one. Specific examples of the α-hydroxy ketone photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1-phenylpropan-1-one.

It is preferable that the transparent pattern 3 used in the present invention selectively reflects one of the left circularly polarized light component and the right circularly polarized light component with respect to incident light. In particular, when a cholesteric liquid crystal material is used as a material having the wavelength selective reflectivity and the multilayer structure of the transparent pattern 3 is formed to have a fixed cholesteric structure, a levorotatory or dextrorotatory cholesteric liquid crystal material is obtained. By selecting, it is possible to selectively reflect a circularly polarized light component in a desired rotation direction (a circularly polarized light component whose electric field vector rotates in the same direction as the rotation direction of the helical axis of the cholesteric liquid crystal) with respect to incident light. preferable. This property is called circularly polarized light selective reflectivity.
In general, “liquid crystal” refers to a liquid state in a narrow sense, but in the specification of the present invention, a liquid crystal material having fluidity is held by liquid crystal by means of crosslinking, cooling, or the like. A liquid crystal that is solidified and maintained in a non-flowing state while maintaining desired performance such as optical characteristics, refractive index, and anisotropy is also referred to as “liquid crystal”.

  In the transparent sheet 1 of the present invention, as shown in FIG. 1, the transparent substrate 2 preferably has a base layer 22 laminated on the surface of a base material 21. And it is preferable that the non-visible light reflective transparent pattern 3 is formed on the surface of the base layer 22 by dot printing as a dot-shaped pattern arranged at a predetermined interval. In addition, when a cross section of the transparent pattern 3 cut along a plane orthogonal to the transparent substrate 2 is observed with a scanning electron microscope, the transparent pattern 3 has a multilayer structure (in particular, a constant repetition period) (multilayer structure). In order to ensure non-visible light reflectivity, it is also preferable to include a film structure (hereinafter also referred to as appropriate).

In the transparent sheet 1 of the present invention, the base layer 22 laminated as desired repels each droplet of ink during dot printing for forming the transparent pattern 3. These droplets rise as a result of being repelled and are greatly curved. These curves are fixed by drying and cross-linking of the droplets, and the transparent pattern 3 includes a multilayer structure having a curved portion. By forming the curved portion, it is possible to obtain a non-visible light reflective pattern-printed transparent sheet 1 having a wide reading angle.
The thickness of the base layer 22 is usually about 0.1 to 10 μm, and is preferably 0.1 to 5 μm from the viewpoint of being able to form a thin film and being inexpensive.

FIG. 2 is a photograph (a) of a dot-shaped cross section of a transparent pattern 3 (cross section cut along a plane orthogonal to the transparent substrate of the transparent pattern), which is one embodiment of the transparent sheet 1 of the present invention, and a cholesteric portion in the partial cross section. It is a scanning electron micrograph (b)-(d) which shows the repeated layer structure of a liquid crystal.
(A) shows that when the primer layer 22 repels the ink constituting the transparent pattern 3, the dot shape of the transparent pattern 3 rises and becomes a disk shape or an elliptical hemisphere. (B) is a partial cross-sectional photograph of the top of the dot shape of (a), and (c) and (d) are partial cross-sectional photographs of the left inclined portion and the right inclined portion of the dot shape of (a), respectively. . As described above, since the dot shape has a long inclined portion, a curved portion is formed in a multilayer film having a cholesteric structure, that is, a parallel plane group, in the entire dot shape, and is microscopically seen in the photographs (b) to (d). A wide reading angle can be realized by the principle described later in combination with a simple curve.
As described above, the curved portion included in the multilayer structure in the present invention includes not only a curved portion caused by the contour shape of each transparent pattern 3 but also a microscopic curved portion in each transparent pattern 3. Is.

  In the present invention, the curved shape of the multilayer film structure over the entire dot shape is such that each film surface constituting the parallel surface group (or a line corresponding to the cut surface of the film surface) is a curved surface as shown in FIG. In addition to a curved line at the corresponding cut surface, it may be a crossingly connected refraction plane (a broken line at the corresponding cut surface) line, or a combination of a curved surface and a refraction plane. When each film surface is a curved surface, each film surface is a continuous curved surface (continuous curve for the corresponding cut surface), as well as a discontinuous curved surface including a fault, cusp, etc. (discontinuous curve for the corresponding cut surface). It may be. Further, in the case where each film surface is a curved surface, each film surface always has a curved surface group that is convex in one direction like a hemispherical surface (a group of curved lines that are convex in one direction in the corresponding cut surface), or a concave surface. It may be any of a curved surface (a group of sinusoidal corrugated curves in the corresponding cut surface) in which the convex surface repeats alternately. Further, the degree of distribution of the tangential angle of the film surface due to the curvature of each film surface is appropriately set according to the application and the design request, but is usually about 10 to 30 °.

In the liquid crystal having the above-described cholesteric (chiral nematic) structure, the axis of each liquid crystal molecule exists in each layer surface of the multilayer structure and is uniformly aligned in a specific direction in the layer surface. In addition, the alignment direction of the liquid crystal molecular axes changes sequentially as a function of the layer thickness direction, and as the direction of rotation proceeds toward the thickness direction of the cholesteric structure, the rotation axis faces the thickness direction of the multilayer film. It has a spiral structure (cholesteric structure) with a constant period rotating in a specific direction in the layer surface of the film. A characteristic of the cholesteric structure is that it is a circularly polarized component in which the direction of rotation of the helix coincides with the direction of rotation of the electric field and reflects circularly polarized light having a wavelength corresponding to the helical pitch. Called sex). The selective reflection wavelength λ (nm) is generally given by the following equation.
λ = p · n · cos θ
p: helical pitch of cholesteric liquid crystal (nm)
n: average refractive index of liquid crystal θ: incident angle of light (angle from surface normal)
One pitch of the cholesteric structure is the direction of the axis of the spiral axis required to draw a spiral and rotate 360 ° as the axis direction of the elongated liquid crystal molecules proceeds in the layer thickness direction (spiral axis, separate from the liquid crystal molecule axis) However, when the section of the transparent pattern cut in a plane perpendicular to the transparent substrate is observed, the liquid crystal molecular axis is aligned in the same plane every time the liquid crystal molecular axis is rotated 180 °. Since it becomes the direction, a repeated layer structure can be seen in the layer thickness direction (see FIGS. 2 to 3). Therefore, the apparent interlayer pitch seen when observing the cross section is ½ of the helical pitch of the liquid crystal. Therefore, if the apparent interlayer pitch seen when the cross section is observed is 250 nm, the pitch of the liquid crystal is 500 nm.

  When circularly polarized light is incident, the rotation direction of the circularly polarized component of the light reflected from the surface of the transparent substrate made of a normal material such as resin or glass is reversed. On the other hand, on the surface of the cholesteric liquid crystal, the circularly polarized component of the light reflected from the surface remains unchanged with the rotation direction unchanged. Therefore, if this property is used, the SN ratio of the reflected light from the non-visible light reflective transparent pattern 3 and the background light (reflected light from other than the pattern portion) can be improved by combining with a circular polarizing filter or the like. Is possible.

  In the case of reflection with a cholesteric structure, the reflection intensity generally increases as the printing thickness (film thickness) increases, but if it is too thick, the liquid crystal orientation is unnecessarily disturbed, the transparency is lowered, and the drying load is increased. The printed thickness of the pattern 3 is usually about 1 to 20 μm, preferably about 3 to 15 μm. In terms of the number of helical pitches of the cholesteric liquid crystal structure, the reflectance is said to be saturated at about 10 to 20 pitches. However, if the liquid crystal composition and the solidification conditions are determined, the film in which the reflection intensity is saturated in actual production. The thickness may be experimentally determined to optimize the reflectivity. Even if the film thickness is more than the above (or the number of pitches), it can be said only from the point of reflectivity. However, if the film thickness becomes thicker than necessary, the printed pattern is likely to be worn and damaged, and the manufacturing cost is unnecessarily high. In order to increase the thickness, it is preferable to set the film thickness to the minimum necessary level.

As the invisible light reflecting material constituting the transparent pattern 3 used in the present invention, a liquid crystal material exhibiting a cholesteric liquid crystal phase having cholesteric regularity is preferable as described above, and a polymerizable chiral agent is mixed with a polymerizable nematic liquid crystal. The polymerizable chiral nematic liquid crystal material (polymerizable monomer or polymerizable oligomer) or polymer cholesteric liquid crystal material can be used. The polymerizable chiral nematic liquid crystal material is polymerized and solidified (cured) by causing a crosslinking reaction or the like by a known method such as irradiation with ionizing radiation such as ultraviolet rays or electron beams, or heating.
In the present invention, among the polymerizable liquid crystal materials, it is preferable to use a crosslinkable polymerizable monomer or polymerizable oligomer having a crosslinkable functional group in the molecule, and having an acrylate structure as the polymerizable functional group. More preferably.

  The liquid crystal material exhibiting (expressing) the cholesteric structure has a high reflectivity (usually 5 to 50% with respect to non-polarized light) in at least a part of wavelengths in a non-visible light (infrared ray or ultraviolet ray) region. In general, high transmittance is not necessarily required at wavelengths in the visible light region. Even if the liquid crystal material exhibiting the cholesteric structure is completely opaque, if the area of the non-formation part (margin part) of the liquid crystal material is appropriately increased and the transmitted light therefrom is used, the transparent pattern This is because, as a whole, it is possible to obtain desired transparency. However, it is needless to say that the liquid crystal material itself has a higher visible light transmittance. In general, when the liquid crystal material having such a cholesteric structure brings a high reflection wavelength region to the infrared or ultraviolet region, the visible light region transmits visible light of about 70% or more with a thickness of about several μm. Get rate. On the other hand, in the non-visible light region, it is common to obtain a high reflectance of about 5 to 50% with respect to non-polarized light. Further, the temperature range in which the polymerizable liquid crystal material exhibits a cholesteric phase is not particularly limited as long as it can be fixed by crosslinking in the state of the cholesteric phase. It is preferable because the drying process during pattern printing and the phase transition of the liquid crystal can be performed simultaneously.

If it is the above materials, liquid crystal molecules can be optically fixed in the state of cholesteric liquid crystal, and a pattern that is easy to handle as the transparent sheet 1 and stable at room temperature can be formed. .
Alternatively, a liquid crystal polymer (polymer cholesteric liquid crystal) that has a high glass transition point and can be solidified into a glass state at room temperature by cooling after heating can be used. Similarly, these materials can also fix liquid crystal molecules optically in the state of liquid crystal having cholesteric regularity, and form a stable pattern at room temperature that is easy to handle as an optical sheet. Because it can.

The crosslinkable polymerizable monomer is disclosed in JP-A-7-258638, JP-A-11-513019, JP-A-9-506088 and JP-A-10-5088822. In addition, a mixture of a liquid crystalline monomer and a chiral compound can be used. For example, a chiral nematic liquid crystal (cholesteric liquid crystal) can be obtained by adding a chiral agent to a liquid crystalline monomer exhibiting a nematic liquid crystal phase. At this time, it is preferable that the nematic liquid crystal and the chiral agent each have a functional group capable of crosslinking, and the cholesteric structure is fixed by crosslinking them.
A method for forming a cholesteric liquid crystal is also described in Japanese Patent Application Laid-Open Nos. 2001-5684 and 2001-110045.

  Examples of nematic liquid crystal molecules (liquid crystalline monomers) that can be used in the present invention include compounds represented by the following formulas (1) to (11). The compounds exemplified here have an acrylate structure and can be polymerized by ultraviolet irradiation or the like.

［化合物（１１）において、Ｘ¹は２〜５(整数）である。］

[In the compound (11), X ¹ is 2 to 5 (integer). ]

Moreover, as the crosslinkable polymerizable oligomer, a cyclic organopolysiloxane compound having a cholesteric phase as disclosed in JP-A-57-165480 can be used.
Further, the liquid crystal polymer includes a polymer in which a mesogenic group exhibiting liquid crystal is introduced into the main chain, a side chain, or both positions of the main chain and the side chain, a polymer cholesteric liquid crystal in which a cholesteryl group is introduced into the side chain, A liquid crystalline polymer as disclosed in Kaihei 9-133810, a liquid crystalline polymer as disclosed in JP-A-11-293252, or the like can be used.

  The chiral agent contained in the transparent ink used in the present invention is a material that has an asymmetric carbon atom and forms a chiral nematic phase by mixing with a nematic liquid crystal, and is not particularly limited as long as it has polymerizability. However, a material having an acrylate structure as exemplified in Formula (12) is preferable because it can be polymerized by ultraviolet irradiation.

［Ｘは２〜５（整数）である。］

[X is 2 to 5 (integer). ]

  In the present invention, the transparent pattern 3 reflects infrared rays or ultraviolet rays, as described above, utilizing the wavelength selective reflectivity (the same principle as Bragg reflection in X-ray diffraction) of a liquid crystal material having a cholesteric structure. Preferably, the selective reflection peak wavelength (wavelength satisfying the Bragg reflection condition) is determined by the pitch length of the cholesteric structure included in the pattern. When nematic liquid crystal and a chiral agent are used as the liquid crystal material, the chiral agent The helical pitch length can be controlled by adjusting the amount of addition. The amount of chiral agent added to obtain the target selective reflection peak wavelength in the infrared or ultraviolet region varies depending on the type of liquid crystal used and the type of chiral agent. For example, the liquid crystal of formula (11) and the chiral agent of formula (12) Is used, a cholesteric phase having a reflection peak in the infrared region is formed by adding about 3 parts by mass of the chiral agent to 100 parts by mass of the liquid crystal, and by adding about 9 parts by mass of the chiral agent to 100 parts by mass of the liquid crystal. A cholesteric phase having a reflection peak in the ultraviolet region is formed. When polymer cholesteric liquid crystal is used as the liquid crystal material, a polymer material having a target pitch length may be selected.

The polymer of nematic liquid crystal molecules and a chiral agent in the present invention can be obtained, for example, by adding a known photopolymerization initiator or the like to a polymerizable nematic liquid crystal and a polymerizable chiral agent and irradiating with ultraviolet rays to cause radical polymerization. .
As the photopolymerization initiator, the above-mentioned photopolymerization initiator used in the photocurable (meth) acrylate resin composition for forming the transparent layer 4 is similarly used.

In the present invention, when the transparent pattern 3 is printed, it is preferable to use a coating solution in which a polymerizable monomer, a polymerizable oligomer, or a chiral agent is dissolved in a solvent.
The solvent is not particularly limited as long as it has sufficient solubility in the material, and a known one may be used. For example, anone (cyclohexanone), cyclopentanone, toluene, acetone, MEK (methyl ethyl ketone), MIBK (methyl) Common solvents such as isobutyl ketone), DMF (N, N-dimethylformamide), DMA (N, N-dimethylacetamide), methyl acetate, ethyl acetate, n-butyl acetate, 3-methoxybutyl acetate, A mixed solvent is mentioned.

The base material 21 of the transparent substrate 2 used for the transparent sheet 1 of the present invention is not particularly limited as long as it is a material that transmits visible light, but is preferably formed of a material with few optical defects. A so-called film, sheet, or plate is appropriately used. In addition to a flat surface, a curved surface shape may be used so as to match the curved surface of the display surface. Specifically, as the material of the base material 21, resins such as glass, TAC (triacetyl cellulose), PET (polyethylene terephthalate), polycarbonate, polyvinyl chloride, acrylic, and polyolefin are preferably used. Further, the thickness is appropriately selected from the range of about 20 to 5000 μm, preferably from the range of 100 to 5000 μm from the viewpoint of anti-curl property, according to the material, required performance, and usage form.
In the case of using a material that easily dissolves or swells in a solvent such as a polymer film such as a TAC film as the base material 21, the substrate is not attacked by the solvent in the coating liquid used for printing the transparent pattern 3. A barrier layer may be provided on the substrate 21. For example, a water-soluble substance such as PVA (polyvinyl alcohol) or HEC (hydroxyethyl cellulose) may be used as the barrier layer.

  As a material used for the base composition for forming the base layer 22 of the transparent substrate 2 according to the present invention, a substance having a property of repelling ink droplets forming a transparent pattern is selected. In addition, a transparent resin using an organic resin, an inorganic resin, or the like is particularly preferable in that a layer can be formed by coating. The resin used for the base composition is not particularly limited, and examples thereof include thermoplastic resins, thermosetting resins, and ionizing radiation curable resins. Among these, from the viewpoint of obtaining durability, solvent resistance, and a wide reading angle, a resin of a type that is cured by crosslinking is preferable, and further, it can be crosslinked in a short time by ionizing radiation such as ultraviolet rays and electron beams. An ionizing radiation curable resin is more preferable. If these resins themselves do not have sufficient liquid repellency for the transparent pattern forming ink, a liquid repellency leveling agent is further added.

Examples of the thermoplastic resin include acrylic resins, polyester resins, thermoplastic urethane resins, vinyl acetate resins, cellulose resins, and the like, and the transparent substrate 2 is made of cellulose such as TAC (triacetyl cellulose). In the case of a resin, as the thermoplastic resin, for example, a cellulose-based resin such as nitrocellulose, acetylcellulose, cellulose acetate propionate, and ethylhydroxyethylcellulose is preferable.
Examples of the thermosetting resin include phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, urethane resin, epoxy resin, aminoalkyd resin, melamine-urea cocondensation resin, silicon resin. , Polysiloxane resin, curable acrylic resin, and the like. When a thermosetting resin is used, a curing agent such as a crosslinking agent and a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier and the like can be further added as necessary.

As the material used for the base composition, ionizing radiation curable resin is preferable as described above, and various reactive monomers and / or reactive oligomers are preferably used. For example, examples of the reactive monomer include the above-mentioned polyfunctional (meth) acrylate monomer. Examples of the reactive oligomer include an oligomer having a radical polymerizable unsaturated group in the molecule, for example, the above-mentioned polyfunctional (meth) acrylate oligomer.
Moreover, as a polymerization initiator of a reactive monomer or a reactive oligomer, the above-mentioned bisacylphosphine oxide-based or α-aminoketone-based photopolymerization initiator may be mentioned.

  As the liquid repellent leveling agent used in the base composition according to the present invention, any liquid repellent leveling agent may be used as long as it repels ink that forms the transparent pattern 3. As the type of the leveling agent, various compounds such as silicone, fluorine, polyether, acrylic acid copolymer and titanate can be used. In order to repel ink of a liquid crystal material forming a fixed cholesteric structure, an acrylic acid copolymer leveling agent (for example, trade name “BYK361” manufactured by BYK Chemie) is particularly preferable. The addition amount may be appropriately adjusted according to a desired reading angle. When the resin itself selected as the material for the base composition already has sufficient liquid repellency for the transparent pattern forming ink, the addition of the liquid repellency leveling agent can be omitted. Examples of the resin having high liquid repellency include silicon resin and fluorine resin.

From the viewpoint of obtaining a wide reading angle, in addition to the above-mentioned leveling agent (liquid repellent material), the base layer 22 is further added with fine particles to form a cholesteric liquid crystal formed thereon. Concavities and convexities may be formed on the Bragg reflecting surface of the structure.
As the fine particles, those usually used can be added in an appropriate amount without any particular restriction. For example, inorganic particles include transparent particles such as α-alumina, silica, kaolinite, glass, calcium carbonate, diamond, silicon carbide and the like. Examples of the particle shape include a sphere, a spheroid, a polyhedron, a truncated polyhedron, and a scaly shape, and are not particularly limited, but a spherical shape is preferable. Organic materials include synthetic resin beads such as cross-linked acrylic resin and polycarbonate resin. Among these, α-alumina and silica are preferable and spherical ones are particularly preferable because they are highly transparent and easily obtain spherical particles. The particle diameter of the fine particles is about 0.01 to 20 μm. Alternatively, the surface of the transparent pattern 3 may be curved to an upwardly convex curved surface (for example, a curved surface such as a hemispherical surface), or fine irregularities may be formed on the transparent pattern surface by embossing.

  Further, in the underlayer 22, if necessary, for example, in the range that does not hinder the invisible light reflection function, the moire prevention effect, and the transparency of the transparent pattern 3 in the present invention, Various known additives in the ink may be added as appropriate. Examples of the additive include a light stabilizer such as an ultraviolet absorber, an antistatic agent, a heat stabilizer, a lubricant, a surfactant, and a dispersion stabilizer.

  The transparent layer 4 or the underlayer 22 can be formed of a (meth) acrylate resin composition or an ink of the underlayer composition obtained as described above by a known layer forming method such as a coating method or a printing method. . Specifically, the (meth) acrylate resin composition ink is applied to the printed surface of the transparent pattern 3, or the base composition ink is applied to the base material 21, and a coating method such as roll coating, comma coating, or die coating, or a screen. What is necessary is just to form by printing methods, such as printing and gravure printing.

In the transparent sheet 1 of the present invention, the printing method of the transparent pattern 3 is not particularly limited, and a known method can be used. Examples thereof include a flexographic printing method, a gravure printing method, a stencil printing method, and an ink jet printing method. Can be mentioned.
The transparent pattern 3 obtained as described above preferably has a selective reflection peak wavelength at 800 nm to 950 nm or 200 nm to 400 nm from the viewpoint of improving reading accuracy.
As the ultraviolet reflective pigment, a known material can be used as long as it exhibits a desired reflectance at a target wavelength. For example, an oxide such as titanium, zirconium, zinc, indium, or tin, or a sulfide of zinc Or nitrides such as silicon and boron are preferably used.

In the transparent sheet 1 of the present invention, the transparent pattern 3 is obtained by reading a reflection pattern of invisible light with an input terminal capable of irradiating and detecting invisible light, and obtaining position information (position coordinates) of the input terminal on the transparent sheet. This is a pattern that can be provided, and is set so that position information of the input terminal on the sheet surface can be derived from a partial pattern read by an input terminal equipped with a sensor.
FIG. 3 is an enlarged plan view of an essential part showing an example in which dot-shaped reflective transparent patterns are irregularly arranged in the transparent sheet 1 of the present invention. In the example of FIG. 3, reference points arranged at equal intervals in the vertical and horizontal directions are set, dots that are displaced vertically and horizontally with respect to the reference points are arranged, and the relative positional relationship of these dots from the reference points is used. This method is particularly preferable because it can be easily produced. This method is advantageous in increasing the resolution of the input device because the dot size can be made small and constant.
In addition, by setting a plurality of dot shapes, in the plane, a pattern that is a combination of these multiple-shaped dots arranged within a predetermined range, changing the thickness of the ruled lines arranged vertically and horizontally, Examples include a combination of sizes of overlapping portions of the ruled lines within a predetermined range, and a combination of x and y coordinate values directly with vertical and horizontal sizes of dots.
When the transparent pattern 3 according to the present invention is formed by dot printing in which a combination of dots is patterned, the printing thickness (film thickness) can be suitably increased.

  In the transparent sheet 1 of the present invention, in order to detect a reflection pattern by an infrared sensor or an ultraviolet sensor provided in the input terminal, it is preferable that the invisible light reflectance at the selective reflection peak wavelength is large. Usually, the reflectivity is about 5% or more at the selective reflection peak wavelength, and preferably 20% or more. The reflection by the cholesteric structure has the property of selectively reflecting circularly polarized light in the same direction as the cholesteric helix. Therefore, when non-polarized light (including equal amounts of both right and left polarized components) is incident, the maximum is 50%. Reach only to the extent. Therefore, if light that contains only circularly polarized light in the same direction as the direction of the spiral of the cholesteric structure is incident from the beginning, the reflection is 100% theoretically (if the loss due to absorption, scattering, etc. is ignored). Rate is also possible.

  When the printed pattern is a dot-shaped reflective transparent pattern, the dot shape is not particularly limited as long as it can be easily distinguished from the adjacent dots. Usually, the shape in plan view is a circle, an ellipse, a triangle, a quadrangle, a 5 A shape such as a polygon such as a square, a hexagon, and an octagon (positive or unequal side) is used. The size in plan view of each dot is not particularly limited as long as it is appropriately determined depending on the application, but is usually the size of the pass (the diameter in the case of a circle, the average value of the short radius and the long radius in the case of an ellipse, In the case of a polygon, the average diagonal length or circumscribed circle diameter) is about 1 to 200 μm. These dots may be of the same shape and the same size over the front surface, or two or more types having different one or both of the shape and size may be mixed. The three-dimensional shape of the dots is preferably a disk shape or an elliptical hemisphere that is raised upward. The dimension in the thickness direction of the dot corresponds to the printing thickness.

FIG. 4 is a schematic view of the entire system using the transparent sheet 1 of the present invention.
In the present invention, the transparent pattern 3 can provide the position information of the input terminal 6 on the transparent sheet 1 by reading the reflection pattern of the infrared or ultraviolet light by the input terminal 6 capable of irradiating and detecting infrared or ultraviolet light. Accordingly, the input terminal 6 that can be used is not particularly limited as long as it can emit infrared rays or ultraviolet rays i and can detect the reflected light r of the pattern, as shown in FIG. For example, as an example in which the pen-type input terminal 6 also includes the read data processing device 7, a pen tip, an infrared ray or an ultraviolet ray irradiation unit that is not provided with ink, graphite, or the like disclosed in Japanese Patent Application Laid-Open No. 2003-256137 is provided. Examples include a built-in CMOS camera, a processor, a memory, a communication interface such as a wireless transceiver using a Bluetooth technology, a battery, and the like.

  As an operation of the pen-type input terminal 6, when the pen tip is drawn so as to be brought into contact with the front surface of the transparent sheet 1 printed with a dot-shaped reflective transparent pattern as shown in FIG. The terminal 6 detects the pen pressure applied to the pen tip, and the CMOS camera operates to irradiate a predetermined range in the vicinity of the pen tip with infrared rays or ultraviolet rays having a predetermined wavelength emitted from the infrared ray or ultraviolet ray irradiation unit, and to capture a pattern. (Pattern imaging is performed, for example, several tens to 100 times per second). When the pen-type input terminal 6 includes the read data processing device 7, the input trace associated with the movement of the pen tip during handwriting is digitized and converted into data by analyzing the captured pattern with a processor. The input trajectory data is generated and transmitted to the information processing apparatus.

Note that a communication interface such as a wireless transceiver using a processor, memory, Bluetooth technology, and the like, and a member such as a battery are provided outside the pen-type input terminal 6 as a read data processing device 7 as shown in FIG. May be. In this case, the pen-type input terminal 6 may be connected to the read data processing device 7 with an electric wire or an electric wire 8 or may transmit read data wirelessly using radio waves, infrared rays, ultraviolet rays, or the like.
In addition, the input terminal 6 may be a reader as described in JP-A-2001-243006.

The medium 5 on which the transparent sheet 1 of the present invention is mounted displays various image information. The image information to be displayed may be in the form of either a still image or a moving image. The types of information include encryption codes such as letters, numbers, figures, barcodes, and photographic images (landscapes, people, paintings, and other various types). And so on. Specific examples of the medium 5 include a CRT (cathode ray tube), an LCD (liquid crystal display device), a PDP (plasma display), an EL (electroluminescence) display device, and the like, or paper on which an image is printed, a resin film, and the like. Examples of the usage or specification form include various types described later (such as a mobile phone). It may be connected to an information processing apparatus that processes handwritten input data, or may be independent. The former is preferable because the locus at the time of handwriting input can be displayed on the screen and intuitive input is possible, but the present invention is not limited to handwriting input, and any input method may be used.
Here, examples of information processing apparatuses that handle input information by handwriting or other methods include various portable terminals such as mobile phones and PDAs, personal computers, videophones, televisions having an intercommunication function, Internet terminals, and the like. it can. Or a book, a brochure, a catalog, a form, an instruction manual, etc. can be illustrated.

  Furthermore, in order to ensure the visibility of the medium 5 behind the transparent sheet 1 of the present invention, an antireflection film or the like for preventing reflection of visible light may be provided on the sheet surface or inside. The material of the antireflection film is not particularly limited, and those used in the field of a normal transparent sheet for display 1 and lenses can be used. For example, a dielectric in which a thin film of a low refractive index material such as magnesium fluoride or fluorine resin and a thin film of a high refractive index material such as zirconium oxide or titanium oxide are laminated so that the low refractive index thin film is the outermost surface A multilayer film or the like is a typical one. Needless to say, the antireflection film is provided so as not to prevent reflection of infrared or ultraviolet light for detecting position information reflected from the transparent pattern (selection of material or provision of the transparent pattern 3 is not covered). Etc.) Necessary.

The read data processing device 7 applicable in the present invention has a function of calculating position information from continuous imaging data read by the input terminal 6, combining it with time information, and providing it as input trajectory data that can be handled by the information processing device. If it has, it will not specifically limit, What is necessary is just to comprise members, such as a processor, memory, a communication interface, and a battery.
The read data processing device 7 may be built in the input terminal 6 as disclosed in Japanese Patent Laid-Open No. 2003-256137, or may be built in an information processing device including the medium 5. Further, the read data processing device 7 may transmit the position information wirelessly to the information processing device provided with the medium 5, or may be transmitted by a wired connection connected by an electric wire or an electric wire 8.
The information processing apparatus connected to the medium 5 sequentially updates the images displayed on the medium 5 based on the trajectory information transmitted from the read data processing apparatus 7, thereby converting the trajectory input by handwriting on the input terminal 6 into paper. The image can be displayed on the medium 5 in real time (or with an appropriate time delay if necessary) as if it were written with a pen. Of course, it is arbitrarily possible to display the handwriting input trajectory and the display image in a superimposed manner or separately.

The pattern-printed transparent sheet 1 of the present invention can be detachably mounted so as to face the front surface of the medium 5. Here, “attached facing the front surface” means, for example, a case where the transparent sheet 1 is disposed in direct contact with the surface of the medium 5 or an adhesive layer or adhesive layer. In this case, the concept further includes a case where the medium 5 is disposed in front of the medium 5 in a non-contact state through a gap. In this way, not only one medium but also another medium can be loaded. In addition, it is preferable that the transparent sheet 1 itself includes a mounting means for the medium 5 so that the transparent sheet 1 can be mounted without performing processing for mounting on the medium side. The mounting means may be provided integrally with the transparent sheet 1 or may be provided separately.
Examples of such mounting means include a device that hooks a buckle-shaped object on the corner portion of the medium 5 and a device that sandwiches an end portion of the medium 5. In the case of attaching to the front surface of the medium 5, a sticking tool that is provided on the contact surface side that comes into contact with the medium 5 and has adhesiveness or adhesiveness for sticking to the medium 5 can be mentioned. Moreover, as a sticking tool, what has the adhesiveness or adhesiveness integrally attached to the transparent sheet 1, and the thing containing the adhesive agent, adhesive agent, etc. which were directly applied to the contact surface are mentioned. In addition, among adhesives, in particular, an adhesive form that can be bonded only by pressing without being subjected to chemical reaction or energy supply such as irradiation of radiation, heating, etc., and can be peeled again after bonding. It is called sex. Further, among adhesives, a form in which the adhesiveness is particularly sticky is referred to as an adhesive.
In the present invention, the medium 5 to be mounted is not limited to a display device or means for displaying an image, and may be any medium. For example, paper, plastic, glass, etc. may be used. Further, the reflection pattern printed transparent sheet 1 may be mounted on the medium 5 instead of being adhered, and may be placed (arranged) on the medium, or may be disposed in a non-contact state as described above. .

The pattern printed transparent sheet 1 of the present invention is preferably separated from the transparent sheet 1 in order to improve the manufacturing convenience. Specifically, a cutting tool such as a scissors or a special cutting tool, a perforation, a half cut (cutting a cut with a depth less than the full thickness in the thickness direction. Packaging material. Etc.), which can be separated by hand by putting in, etc. If it is such, since it becomes possible to cut | disconnect according to the magnitude | size of the medium 5 which each user owns on the user side, the manufacturer side sets to several kinds of predetermined sizes. This is because a manufactured sheet may be manufactured. Further, a perforation may be made in the standard size of the general-purpose medium 5.
Also, if such usage is possible, it is possible to divide one sheet on which a pattern providing position information is printed, and to indicate different coordinate ranges for each sheet. When such a sheet is used, for example, if a sheet indicating continuous coordinates is applied to adjacent media, continuity can be given to input data. Moreover, a different meaning can be given to each transparent sheet 1 by switching and using a plurality of transparent sheets 1 having different coordinate ranges for one input device.

Since the transparent sheet 1 of the present invention can be detected at a wide reading angle, the detection capability of the printed position information is remarkably improved.
In addition, the transparent sheet 1 of the present invention can be mounted on an existing medium as it is, and can be manufactured more easily than an electrostatic or pressure-sensitive position input device incorporated in the medium. Thus, weight reduction, cost reduction, and enlargement can be easily achieved. Further, even if the function of providing position information is reduced because the pattern capable of providing printed position information becomes thin or scratched, only the transparent sheet 1 needs to be replaced. It becomes easy to handle for the user.
The transparent sheet 1 of the present invention can be used as a liquid crystal protective sheet when it is mounted on a liquid crystal display.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Example 1
(1) Preparation of coating liquid for infrared reflective transparent pattern Polymerizable acrylate structure (acrylate group) at both ends, mesogenic structure at the center, spacer between the acrylate, nematic-isotropic transition temperature 100 parts by mass of a monomer (having a molecular structure represented by the chemical formula (9)) having a temperature of about 110 ° C. and a chiral agent having a polymerizable acrylate group at both ends (the molecular structure represented by the chemical formula (12)) A cyclohexanone (hereinafter abbreviated as anone) solution having 3 parts by mass dissolved in cyclohexanone was prepared. In addition, 4 mass parts photopolymerization initiator diphenyl- (2,4,6-trimethylbenzoyl) phosphine oxide (trade name “Lucirin TPO” manufactured by BASF) was added to this anone solution.
(2) Preparation of Coating Solution for Ink Repellent Underlayer 100 parts by mass of pentaerythritol triacrylate (PETA, Nippon Kayaku Co., Ltd., trade name “KAYARAD PET-30”) and an acrylic acid copolymer leveling agent ( 0.06 parts by mass of a trade name “BYK361N” manufactured by Big Chemie Co., Ltd. and 4 parts by mass of a photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, manufactured by Ciba Specialty Chemicals Co., Ltd., trade name “Irgacure 184”) were added and mixed. Furthermore, an ink-repellent undercoat layer coating solution was prepared by adding and adapting methyl ethyl ketone so that the resin content was 50% by mass.
(3) Preparation of coating solution for clearing layer Trifunctional acrylate monomer (having three acrylate groups) (manufactured by Nippon Kayaku Co., Ltd., trade name “KAYARAD PET-30”, cured coating film The photopolymerization initiator (trade name “Irgacure 184” manufactured by Ciba Specialty Chemicals Co., Ltd.) 4 parts by mass and the leveling agent (manufactured by Dainippon Ink Co., Ltd. 350SF ") 0.02 part by mass was added and mixed, and methyl ethyl ketone was further added and mixed so that the resin content was 50% by mass to prepare a coating solution for a transparent layer.
First, the coating solution for the ink-repellent underlayer (2) was applied on a polyethylene terephthalate (PET) substrate (thickness 100 μm) with a bar coater so that the thickness after curing would be 1 μm. Cured by ultraviolet irradiation. Next, the transparent liquid in the form of (1) is coated on the underlayer by applying a dot-shaped transparent pattern so that the thickness after curing is 6-8 μm by the gravure printing method. Cured. The printing surface of the transparent sheet on which the dot-shaped reflective transparent pattern is printed is coated with the coating solution for the transparent layer (3) by a bar coater, dried, and then irradiated with ultraviolet rays and cured. Thus, a transparent layer having a thickness of 15 μm was formed so as to cover the dot-shaped reflective transparent pattern, thereby producing a transparent sheet. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position (850 nm) to the 30 nm short wavelength side after 500 hours.

Example 2
60 parts by mass of a polyfunctional acrylate oligomer (trade name “Beamset 371”, manufactured by Arakawa Chemical Co., Ltd., Tg of cured coating film: 250 ° C. or higher) and 40 parts by mass of the trifunctional acrylate monomer shown in Example 1 4 parts by mass of a photopolymerization initiator (trade name “Irgacure 184” manufactured by Ciba Specialty Chemicals Co., Ltd.) and a leveling agent (trade name “MCF-350SF” manufactured by Dainippon Ink Co., Ltd.) with respect to 100 parts by mass of the polymerizable compound contained. ) 0.02 part by mass was added and mixed, and methyl ethyl ketone was further added and mixed so that the resin content was 50% by mass to prepare a transparent layer coating solution. It coated on the printing surface of the transparent sheet on which the dot-shaped reflective transparent pattern was printed like Example 1 except having used this coating solution for transparentization layers. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position (850 nm) to the 30 nm short wavelength side after 500 hours.

Example 3
A photopolymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd.) with respect to 100 parts by mass of a bifunctional acrylate monomer (trade name “M215” manufactured by Toa Gosei Co., Ltd., Tg of coating film after curing: 166 ° C.) (Trade name “Irgacure 184”) 4 parts by mass and leveling agent (trade name “MCF-350SF”, manufactured by Dainippon Ink Co., Ltd.) 0.02 parts by mass are added and mixed, and methyl ethyl ketone has a resin content of 50% by mass. Thus, a transparent layer coating solution was prepared by adding and mixing as described above. It coated on the printing surface of the transparent sheet on which the dot-shaped reflective transparent pattern was printed like Example 1 except having used this coating solution for transparentization layers. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position (850 nm) to the 30 nm short wavelength side after 500 hours.

Example 4
A photopolymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd.) with respect to 100 parts by mass of a trifunctional acrylate monomer (trade name “M310” manufactured by Toa Gosei Co., Ltd., Tg of cured coating film: 120 ° C.) (Trade name “Irgacure 184”) 4 parts by mass and leveling agent (trade name “MCF-350SF”, manufactured by Dainippon Ink Co., Ltd.) 0.02 parts by mass are added and mixed, and methyl ethyl ketone has a resin content of 50% by mass. Thus, a transparent layer coating solution was prepared by adding and mixing as described above. It coated on the printing surface of the transparent sheet on which the dot-shaped reflective transparent pattern was printed like Example 1 except having used this coating solution for transparentization layers. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position (850 nm) to the 40 nm short wavelength side after 500 hours.

Example 5
Photopolymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd., trade name “Irgacure 184”, leveling agent (Dainippon Ink Co., Ltd.) with respect to 100 parts by mass of polyfunctional epoxy acrylate (coating film Tg: 100 ° C. after curing) 0.02 parts by mass of a trade name “MCF-350SF” manufactured by the company was added and mixed, and methyl ethyl ketone was further added and mixed so that the resin content was 50% by mass to prepare a transparent layer coating solution. Except for using the chemical layer coating solution, it was coated on the printing surface of a transparent sheet on which a dot-shaped reflective transparent pattern was printed in the same manner as in Example 1. When this sheet was stored at 80 ° C., it was 500. After a time, the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position (850 nm) to the 40 nm short wavelength side.

Comparative Example 1
A film-like pressure-sensitive adhesive mainly composed of acrylic (Tg of the coated film after curing: −10 ° C.) was bonded to the printing surface of the transparent sheet on which the dot-shaped reflective transparent pattern was printed. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position (850 nm) to the 300 nm short wavelength side after 500 hours.

Comparative Example 2
For 100 parts by mass of a polyfunctional urethane acrylate polymer (Tg of coated film after curing: 30 ° C.), 4 parts by mass of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd., trade name “Irgacure 184”), leveling agent ( Dainippon Ink Co., Ltd., trade name “MCF-350SF”) 0.02 part by mass is added and mixed, and methyl ethyl ketone is further added and mixed so that the resin content is 50% by mass to obtain a coating solution for a transparent layer. Prepared. It coated on the printing surface of the transparent sheet on which the dot-shaped reflective transparent pattern was printed like Example 1 except having used this coating solution for transparentization layers. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position (850 nm) to the short wavelength side of 80 nm after 500 hours.

Comparative Example 3
Photopolymerization initiator (trade name, manufactured by Ciba Specialty Chemicals Co., Ltd.) with respect to 100 parts by mass of bifunctional polyethylene glycol diacrylate (trade name “M240” manufactured by Toagosei Co., Ltd., Tg of cured coating film: 50 ° C.) (Name "Irgacure 184") 4 parts by weight and leveling agent (trade name "MCF-350SF" manufactured by Dainippon Ink Co., Ltd.) 0.02 parts by weight are added and mixed, and methyl ethyl ketone is added so that the resin content becomes 50% by weight. A clearing layer coating solution was prepared by adding to and mixing. It coated on the printing surface of the transparent sheet on which the dot-shaped reflective transparent pattern was printed like Example 1 except having used this coating solution for transparentization layers. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position (850 nm) to the 60 nm short wavelength side after 500 hours.

Comparative Example 4
For 100 parts by mass of bifunctional bisphenol A (trade name “M208” manufactured by Toa Gosei Co., Ltd., Tg of cured coating film: 75 ° C.), a photopolymerization initiator (trade name “Ciba Specialty Chemicals Co., Ltd. "Irgacure 184") 4 parts by mass, 0.02 parts by mass of a leveling agent (trade name "MCF-350SF" manufactured by Dainippon Ink Co., Ltd.) are added and mixed, and methyl ethyl ketone is added so that the resin content is 50% by mass. The mixture was mixed to prepare a clearing layer coating solution. It coated on the printing surface of the transparent sheet on which the dot-shaped reflective transparent pattern was printed like Example 1 except having used this coating solution for transparentization layers. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position (850 nm) to the 60 nm short wavelength side after 500 hours.

Comparative Example 5
For 100 parts by mass of trifunctional acrylate monomer (trade name “M220”, manufactured by Toa Gosei Co., Ltd., Tg of cured coating film: 90 ° C.), photopolymerization initiator (manufactured by Ciba Specialty Chemicals, (Trade name “Irgacure 184”) 4 parts by mass and leveling agent (trade name “MCF-350SF”, manufactured by Dainippon Ink Co., Ltd.) 0.02 parts by mass are added and mixed, and methyl ethyl ketone has a resin content of 50% by mass. Thus, a transparent layer coating solution was prepared by adding and mixing as described above. It coated on the printing surface of the transparent sheet on which the dot-shaped reflective transparent pattern was printed like Example 1 except having used this coating solution for transparentization layers. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position (850 nm) to the 60 nm short wavelength side after 500 hours.

  As described above in detail, the non-visible light reflective pattern-printed transparent sheet of the present invention provides a coordinate detection means that can be applied to a data input system for inputting directly by hand on a medium screen or other means. It is a member that is highly transparent and has high practical performance. Various types of information such as various portable terminals such as mobile phones and PDAs, personal computers, videophones, televisions equipped with an intercommunication function, Internet terminals, etc. It can be used in a processing apparatus.

It is sectional drawing which shows one embodiment of the pattern printing transparent sheet of this invention. The transparent pattern dot-shaped cross section (cross section cut along a plane orthogonal to the transparent substrate of the transparent pattern) which is an embodiment of the transparent sheet of the present invention (a), and the cholesteric liquid crystal repetitive layer structure in the partial cross section It is a scanning electron micrograph (b)-(d) which shows. It is a principal part enlarged plan view which shows the example in which the dot-shaped reflective transparent pattern was irregularly arranged in the pattern printing transparent sheet of this invention. It is the schematic of the whole system using the pattern printing transparent sheet of this invention.

Explanation of symbols

1: Pattern printing transparent sheet (transparent sheet)
2: Transparent substrate 21: Base material 22: Underlayer 3: Transparent pattern 4: Transparent layer 5: Medium 6: Input terminal (pen type)
7: Reading data processing device 8: Code i: Infrared ray or ultraviolet ray r: Reflected light

Claims (11)

  A pattern-printed transparent sheet, in which a transparent pattern having a non-visible light reflectivity is printed on the surface of a transparent substrate, and a transparent layer is laminated on the printing surface of the transparent pattern, the transparent layer being a (meth) acrylate resin A pattern-printed transparent sheet comprising the composition and having a glass transition point (Tg) of 100 ° C. or higher.   The pattern-printed transparent sheet according to claim 1, wherein the transparent pattern reflects one of a left circularly polarized component and a right circularly polarized component with respect to incident light.   The pattern-printed transparent sheet according to claim 1, wherein the transparent pattern has a dot shape.   The said transparent pattern contains the multilayer structure which consists of a fixed repetition period when the cross section cut | disconnected by the surface orthogonal to the said transparent substrate is observed with a scanning electron microscope. Pattern printing transparent sheet.   The pattern-printed transparent sheet according to claim 1, wherein the transparent pattern has a selective reflection peak wavelength at 800 nm to 950 nm.   The pattern-printed transparent sheet according to claim 1, wherein the transparent pattern has a selective reflection peak wavelength at 200 nm to 400 nm.   The said transparent pattern is a pattern which can provide the positional information of the input terminal on a transparent sheet by reading the reflection pattern of a non-visible light with the input terminal which can irradiate and detect a non-visible light. The pattern printing transparent sheet in any one.   The pattern-printed transparent sheet according to claim 1, wherein the transparent sheet is a transparent sheet that is mounted to face the front surface of a medium capable of displaying an image.   The pattern-printed transparent sheet according to claim 8, further comprising mounting means for mounting on the medium.   The pattern-printed transparent sheet according to claim 9, wherein the attachment means is an attachment tool that is provided on a contact surface side that comes into contact with the medium and has adhesiveness or adhesiveness to be attached to the medium.   The pattern-printed transparent sheet according to claim 1, which is separable.

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