JP2008242758A - Pattern print transparent sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pattern print transparent sheet which is a member for providing a coordinate detection means which can be applied to a data input system of a direct handwriting type on the screen of a display device, and allows weight reduction, mass production, and cost reduction, and facilitates making a large area, and suppresses the shift of the reflected wavelength of invisible rays. <P>SOLUTION: The pattern print transparent sheet 1 is made by printing a transparent pattern 3 on the surface of a transparent substrate 2, and ink composing the transparent pattern 3 contains materials on which invisible rays of light are reflected, and the materials on which the invisible light rays are reflected are crystal liquid materials having a fixed cholesteric structure having wavelength selection reflexibility to the wavelength of infrared or ultrasonic region, and 60 mol% or more of the liquid crystal materials contained in the transparent pattern 3 is multi-functional liquid crystal materials having two or more functional groups. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pattern-printed transparent sheet that is installed on the front surface of a medium for displaying various image information and provides various information accompanying the image information. Especially, it is a member that provides coordinate detection means that can be suitably applied to a data input system for handwriting directly on the screen of a display device, and is particularly lightweight, mass-produced, inexpensive, and large in area. The present invention relates to a pattern-printed transparent sheet that is easy and can suppress the shift of the reflection wavelength of invisible light.

In recent years, there has been an increasing need to convert handwritten characters, pictures, symbols, and the like into electronic data that can be handled by an information processing device. In particular, handwritten information can be processed in real time without passing through a reading device such as a scanner. There is an increasing demand for a method for inputting data to, etc.
Correspondingly, for example, input means provided with a pen for writing by hand and a writing surface, input locus reading means for reading an input locus at the time of handwriting input by the input means, and the input locus information as electronic data An input trajectory conversion means, and an input trajectory data transmission means for transmitting data converted by the input trajectory conversion means to an information processing apparatus, wherein the input trajectory reading means comprises: The mark that provides position information (coordinates) formed on the writing surface is read by a sensor installed on the pen, and the writing surface absorbs infrared rays as a mark that provides position information. A special paper on which a special dot pattern is printed, and an infrared irradiating unit for the pen to irradiate the writing surface with an infrared ray, and an infrared ray reflected by the dot pattern Writing type input device has been proposed which is provided with an infrared sensor for detecting a turn.
In addition, a pressure-sensitive sensor, electrostatic sensor, optical sensor, etc. are installed on the writing panel to detect writing pressure, static electricity, and shadow when handwritten with a stylus pen or finger on the panel surface. Thus, a write-type input device of a type that acquires an input locus has also been proposed.

However, in the former device, the handwritten content (input locus) can be converted into electronic data, but the direct input object is a dedicated sheet, and a separate display device is required to display the input locus information converted into electronic data. Become. By using a nib with graphite or ink so that the trace can be recorded on the paper, the trace information can be visually confirmed on the paper, but anyway, for example, handwriting input to the chart displayed on the display It is not suitable for intuitive and interactive operation, and requires a wider work space for input. In addition, when a locus is recorded on paper, paper that has been handwritten once cannot be used. Therefore, input paper that is a consumable needs to be prepared, and is not particularly suitable for mobile applications.
On the other hand, in the latter device, the panel to be written is provided with a pressure-sensitive sensor, an electrostatic sensor, and the like, so that it is difficult to reduce the size and weight and thickness of the input device compared to the former device. . Also, it is expensive in terms of cost. In addition, pressure-sensitive sensors and electrostatic sensors may malfunction when touched by hands or cuffs, and touch the side of the little finger side of the palm as when writing on a normal notebook. It becomes unsuitable for the writing method. Such a device can be installed on the front of the display using a transparent material for the writing panel, or by giving the writing panel itself a display function, for example, handwriting input to a chart displayed on the display. Intuitive and interactive operation is possible, but this method is expensive, so it is difficult to enlarge the screen, and it is difficult to reduce the size and weight, so it is not suitable for mobile applications such as mobile phones.

Therefore, in order to solve such a problem, it is possible to input directly handwritten content on the display surface of the display device to the information processing device, and the input device can be manufactured in a compact and inexpensive manner Was desired. In order to realize this, for example, in the former writing type input device, the paper on which the dot pattern as the writing means is printed is made transparent with respect to the light in the visible region, and the front of the display device or Install it on the front.
As a transparent sheet that satisfies such a requirement, for example, Patent Document 1 discloses a transparent sheet that is mounted on the front surface or the front of a display device, and indicates position information for indicating the position of an input locus by an input electronic pen or the like. Is printed using fluorescent ink that emits light that can be read by the input locus reading means when irradiated with light of a predetermined wavelength. However, Patent Document 1 does not describe the type of ink that embodies such a transparent sheet, merely describes the idea or desire of the transparent sheet, and is a specific example of a transparent sheet. There is no.
Further, Patent Document 2 discloses a coordinate input device using a transparent member printed with special ink that reflects an infrared region. However, Patent Document 2 also discloses a type of ink that embodies such a device. Are not described, only ideas or desires are described, and there is no specific example of the transparent sheet.

It is conceivable to use cholesteric liquid crystal as a material that reflects this infrared ray. Based on such an idea, the inventor of the present application previously described in Japanese Patent Application No. 2006-269220 by forming a dot pattern made of cholesteric liquid crystal on a transparent sheet and reflecting light from each dot with a sensor installed on the pen side. A method of reading and identifying as coordinates was proposed. At this time, the reading range of an infrared sensor is generally 800 to 900 nm, and it is said that the sensitivity of a practical infrared sensor is currently 850 nm. Therefore, the wavelength of the reflected light from the dot pattern is also required to be within this range, and the peak center position is preferably around 850 nm.
When various measures were taken for the transparent sheet for position information input having such a configuration, and examination and evaluation proceeded, a new problem was discovered. That is, when the sheet is stored in a high heat or humidity state, the cholesteric orientation changes with time due to secondary factors from the outside, and the selective reflection wavelength peak position is shifted to the visible light region or colored. There's a problem. 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 changes over time, most of the reflected light from the dots will be outside the sensor reading range. Therefore, accurate position information may not be recognized. In addition, there is a problem that a dot pattern that is originally configured to be transparent and invisible is colored and visually observed. From the above, the spectral shift is desired to be within 50 nm, preferably within 40 nm.
Japanese Patent Laid-Open No. 2003-256137 JP-A-2001-243006

  The present invention has been made to solve the above-described problems, and can be suitably used for providing additional information to an image display medium, for example, directly inputting data by handwriting on a display device. An object of the present invention is to provide a pattern-printed transparent sheet that is lightweight, can be mass-produced, is inexpensive, can be easily increased in area, and can suppress a shift in the reflection wavelength of invisible light.

As a result of intensive research to achieve the above object, the present inventors have used a liquid crystal material having a cholesteric structure in which 60 mol% or more is polyfunctional as a material that reflects invisible light rays typified by infrared rays. Thus, for example, when the heat resistance test is performed at 80 ° C., the present invention has been completed so that the shift amount of the reflected wavelength can be suppressed within 40 nm within the pen reading range.
That is, according to the present invention, a transparent pattern having a non-visible light reflection property is printed on the surface of a transparent substrate, and the ink constituting the transparent pattern includes a material that reflects the non-visible light, and reflects the non-visible light. The material is a liquid crystal material having a fixed cholesteric structure having wavelength selective reflectivity with respect to a wavelength in a non-visible light region, and 60 mol% or more of the liquid crystal material included in the transparent pattern is two or more. The present invention provides a pattern-printed transparent sheet that is a polyfunctional liquid crystal material having a functional group of:

  The pattern-printed transparent sheet of the present invention can be suitably used for providing additional information to an image display medium, for example, by handwriting directly on a display device and inputting the position coordinates of handwritten information. In addition to being able to reduce the work space without impeding the visibility of the medium, it is lightweight, can be mass-produced, inexpensive, easy to increase in area, and can suppress the shift of the reflection wavelength of invisible light.

  As shown in FIG. 1, the pattern-printed transparent sheet 1 of the present invention is formed by printing a transparent pattern 3 on the surface of a transparent substrate 2, and the ink constituting the transparent pattern 3 includes a material that reflects invisible light, The material that reflects invisible light is a liquid crystal material having a fixed cholesteric structure having wavelength selective reflectivity with respect to wavelengths in the invisible light wavelength region, typically infrared or ultraviolet region. 60 mol% or more of the liquid crystal material included in the transparent pattern 3 is a polyfunctional liquid crystal material having two or more functional groups.

This polyfunctional liquid crystal material is preferably 75 mol% or more of the liquid crystal material contained in the transparent pattern.
When the polyfunctional liquid crystal material is 60 mol% or more, the cholesteric structure is less likely to change due to changes over time or external disturbances such as heating, so that a stronger liquid crystal structure can be formed. Is suppressed.
The invisible light is preferably infrared or ultraviolet. Infrared rays are preferably light in the near infrared region having a wavelength of 800 to 2500 nm, and infrared rays having a selective reflection peak wavelength at 800 to 950 nm are preferred. In particular, among the near infrared rays in the near infrared region of 800 to 2500 nm, the reading range of the infrared sensor is generally 800 to 900 nm, and the best sensitivity of the sensor is 850 nm. Accordingly, the reflection peak from the dot-shaped reflective transparent pattern is also required to be within this range, and the peak center position is more preferably 850 nm. Even if the initial peak center position is 850 nm, when the peak position is shifted to the visible region side by 50 nm or more due to changes over time, most of the reflected light from the dots falls outside the sensor reading range. Therefore, accurate position information cannot be recognized. And a transparent pattern will color and will be visually observed. From the above, the spectral shift is preferably within 50 nm, and preferably within 40 nm. Further, the ultraviolet light is preferably ultraviolet light having a selective reflection peak wavelength at 200 to 400 nm. Similarly, it is preferable to select a wavelength selective reflection band that is separated from the short wavelength side of the visible region by a short wavelength side by an amount equal to or more than the retention wavelength shift amount.

The ink constituting the invisible light reflective transparent pattern (hereinafter also referred to simply as the transparent pattern) used in the present invention has a fixed cholesteric structure and has a function of reflecting invisible light. Although the component is not specifically limited, the liquid crystal material which expresses the cholesteric structure applicable to the transparent sheet of this invention is demonstrated below.
The liquid crystal molecules contained in the transparent ink used in the present invention is a liquid crystal material exhibiting a cholesteric liquid crystal phase, and is not particularly limited as long as it has cholesteric regularity. In order to suppress fluctuations in the cholesteric structure (especially the distance between Bragg reflection surfaces) due to external disturbance factors such as heat, a polyfunctional liquid crystal material having two or more polymerizable functional groups in the molecule is added to 60 mol% of the total liquid crystal material. More preferably, it is selected to contain 75 mol% or more. Here, typical examples of the functional group include a (meth) acryloyl group, a (meth) acryloyloxy group, and an epoxy group. The number of functional groups in one molecule of the polyfunctional liquid crystal material occupying 60 mol% or more in the liquid crystal molecules is typically 2 (bifunctional), but the other 3 ( (Trifunctional), 4 (4 functional), 5 or more (5 functional or more) can also be used. As a specific composition, a polymerizable chiral nematic liquid crystal material (polymerizable monomer or polymerizable oligomer) obtained by mixing a polymerizable chiral agent with a polymerizable nematic liquid crystal, or a polymer cholesteric liquid crystal material can be used. .
In the present invention, among the polymerizable liquid crystal materials, it is preferable to use a polymerizable monomer or polymerizable oligomer having an acrylate structure as a polymerizable functional group.
The liquid crystal means, in a narrow sense, a fluid liquid substance having optical anisotropy. However, in the present invention, in addition to the liquid crystal, in addition to this, the liquid narrowly defined liquid crystal is polymerized, cooled, or the like. In addition, the term also includes a solidified product while maintaining optical anisotropy.
The liquid crystal material exhibiting (expressing) the cholesteric structure is essentially a visible light region as long as it exhibits a high reflectance (usually about 5 to 50%) at at least a part of wavelengths in the non-visible light region. High transmittance is not always required at the wavelength of. Even if the liquid crystal material having the cholesteric structure is completely opaque, if the area of the non-formation part (margin part) of the liquid crystal material is appropriately large and the transmitted light from there is used, the transparent pattern It is because it is possible to obtain desired transparency as a whole. However, it is needless to say that the liquid crystal material itself has a higher visible light transmittance. In general, when a liquid crystal material having such a cholesteric structure takes a high reflection wavelength region to a non-visible light region, the visible light region has a thickness of about several μm and a visible light of about 70% or more. Obtain light transmittance. On the other hand, in the non-visible light region, it is common to obtain a high reflectance of about 5 to 50% in the selective reflection wavelength region. The temperature range in which the polymerizable liquid crystal material exhibits a cholesteric phase is not particularly limited as long as the polymerizable liquid crystal material can be fixed in a cholesteric phase state. This is preferable because the drying process during printing and the phase transition of the liquid crystal can be performed simultaneously.

If it is the above materials, a liquid crystal molecule can be optically fixed with the state of a cholesteric liquid crystal, and the pattern stable at normal temperature which can be easily handled as a transparent sheet 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 form liquid crystal molecules that are optically fixed in the form of liquid crystals having cholesteric regularity, and form a stable pattern at room temperature that is easy to handle as an optical sheet. Because you can.
A method for forming a cholesteric liquid crystal is also described in JP-A 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). ]

  Examples of the liquid crystal polymer include 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). ]

  The property of reflecting the invisible light of the transparent pattern in the present invention utilizes the wavelength selective reflectivity (similar principle as Bragg reflection in X-ray diffraction) of a liquid crystal material having a cholesteric structure. The reflection peak wavelength (wavelength satisfying the Bragg reflection condition) is determined by the pitch length of the cholesteric structure contained in the pattern. When nematic liquid crystal and a chiral agent are used as the liquid crystal material, the addition amount of the chiral agent is adjusted. By doing so, the pitch length can be controlled. In order to obtain the target selective reflection peak wavelength in the non-visible light region, the amount of chiral agent added 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) are used. When used, a cholesteric phase having a reflection peak in the infrared region is formed by adding about 3 parts by weight of the chiral agent to 100 parts by weight of the liquid crystal, and an ultraviolet light by adding about 5 parts by weight of the chiral agent to 100 parts by weight of the liquid crystal. A cholesteric liquid crystal having a reflection peak in the 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. .
In the present invention, when a transparent pattern 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.
In the transparent sheet of the present invention, the printing method of the transparent pattern 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. .

As one embodiment of the pattern printing transparent sheet of the present invention, as shown in FIG. 2, the transparent substrate 2 comprises a base material 21 and a base layer 22 laminated on the transparent pattern 3 printing side surface of the base material 21, Preferably, the underlying layer 22 repels ink that forms the transparent pattern 3.
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 (also referred to as a multilayer film structure, which is referred to as a multilayer film structure). In order to ensure non-visible light reflectivity, it is preferable to include them.

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 this curved portion, a non-visible light reflective pattern-printed transparent sheet having a wide reading angle can be obtained.
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. 3 is a photograph (a) of a dot-shaped cross section of a transparent pattern (cross section cut along a plane perpendicular to the transparent substrate of the transparent pattern), and a partial cross section of the cholesteric liquid crystal in one embodiment of the transparent sheet of the present invention. It is a scanning electron micrograph (b)-(d) which shows a repeated layer structure.
(A) shows that the dot shape of the transparent pattern 3 rises by repelling the ink which comprises a transparent pattern in a base layer, 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 but also a microscopic curved portion in each transparent pattern. is there.

  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 curved as shown in FIG. In addition to a curved line at the corresponding cut surface, it may be a crossed and 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 light component in which the direction of rotation of the spiral coincides with the direction of rotation of the electric field and reflects circularly polarized light having a wavelength corresponding to the helical pitch (selective reflectivity). 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 °. Because of the direction, a repeated layer structure can be seen in the layer thickness direction (see FIG. 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.

  Further, as a material used for the base composition for forming the base layer 22, 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 adding the above-mentioned leveling agent (liquid repellent material), the base layer 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 50 μm to 5 mm. 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 base layer, if necessary, for example, in the range of not impeding the non-visible light reflection function, moire prevention effect, and transparency of the transparent pattern in the present invention, for example, a coating liquid or ink Various known additives 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 undercoat layer can be formed from a (meth) acrylate resin composition obtained as described above or an ink of the undercoat composition 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 printing surface of the transparent pattern 3, or the base composition ink is applied to the base material, using 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.
The base material 21 in the transparent sheet 1 of FIG. 2 is not particularly limited as long as it is a material that transmits visible light, and the same material as the transparent substrate described below can be used.

As shown in FIG. 4, the pattern-printed transparent sheet 1 of the present invention reads the reflection pattern of the transparent sheet 1 by using an input terminal 6 that can irradiate and detect non-visible light, and thus on the transparent sheet 1. Information about the position of the input terminal (position coordinates) can be provided.
The pattern-printed transparent sheet 1 of the present invention is preferably mounted on a display device 5 capable of displaying an image, and is preferably mounted facing the front surface of the display device.
Note that mounting attached to the front face includes both a form in which the display apparatus is attached in close contact with the front face of the display apparatus and a form in which the display apparatus is mounted in an isolated state through the gap.
In the pattern-printed transparent sheet of the present invention, the pattern 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. .
Such patterns are also exemplified in Patent Documents 1 and 2. For example, a plurality of dot shapes are set, and a combination of these plural-shaped dots arranged within a predetermined range in a plane is used. Something like a pattern, some where the thickness of the ruled lines arranged vertically and horizontally is changed, and the combination of the sizes of the overlapping parts of the ruled lines within a predetermined range is patterned. In particular, a simple and suitable one is to set reference points that are evenly spaced in the vertical and horizontal directions, and to place dots that are displaced vertically and horizontally with respect to this reference point. In addition, a method using the relative positional relationship of these dots from the reference point can be used. This method is advantageous in increasing the resolution of the input device because the dot size can be made small and constant.
In the present invention, the shape of the transparent pattern in plan view is appropriately selected according to the application. A dot (dot) shape, a line segment (striped) shape such as a barcode, and the like are typical. In particular, when position information (coordinates) is input, the transparent pattern is preferably a dot pattern.

In the pattern-printed transparent sheet of the present invention, in order to detect a reflection pattern by a non-visible light sensor provided in the input terminal, it is preferable that the non-visible light reflectance at the selective reflection peak wavelength is large. Usually, the reflectivity is about 5 to 50% at the selective reflection peak wavelength, and preferably 20% or more. The reflection by the cholesteric structure has a property of reflecting only circularly polarized light in the same direction as the cholesteric spiral, and therefore reaches only about 50% at the maximum.
In the case of reflection by a cholesteric structure, the reflection intensity is generally larger when the printing thickness is thick, but if it is too thick, the orientation of the liquid crystal is disturbed, the transparency is lowered, and the drying load is increased. The printing thickness is usually about 1 to 20 μm, preferably about 3 to 10 μm.
When the print pattern is a dot pattern, the dot shape is not particularly limited as long as it can be easily distinguished from adjacent dots, and usually, the shape in plan view is a circle, an ellipse, a polygon, or the like. The three-dimensional shape of the dot is not particularly limited and is usually a disc shape, but may be a hemispherical shape or a concave shape.

The transparent substrate used in the pattern-printed transparent sheet 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. Specifically, as the material for the transparent substrate, glass, TAC (triacetyl cellulose), PET (polyethylene terephthalate), polycarbonate, polyvinyl chloride, acrylic, polyolefin, or the like is preferably used. Moreover, thickness is suitably selected from the range of about 20-5000 micrometers according to material, required performance, and a usage form.
In the case where a material that is easily dissolved or swelled in a solvent such as a polymer film such as a TAC film is used as the transparent substrate, a barrier is provided on the substrate so that the substrate is not attacked by the solvent in the coating solution used at the time of transparent pattern printing. For example, a water-soluble substance such as PVA (polyvinyl alcohol) or HEC (hydroxyethyl cellulose) may be used as the barrier layer.

In addition, in the pattern-printed transparent sheet of the present invention, when handwriting input with an input terminal such as a pen type, in order to give strength that can withstand repeated input terminals or to make the appearance completely transparent, A transparent layer (or a hard coat layer (a surface protective layer made of a hard coating) may be provided to cover the gap between the patterns with a transparent material having a refractive index close to that of the pattern material. The transparent layer may be added with functions such as wear resistance, antireflection, anti-slip, antistatic, antifouling, antiglare, etc. The material of the transparent layer is not particularly limited and is usually Those used in the field of transparent sheets and lenses can be used, for example, acrylic resin, silicon-based resin and the like which are crosslinked and cured by ultraviolet rays, electron beams, heat, etc., and have a glass transition temperature of 100. ℃ or more There acrylic resin is preferred.
Furthermore, in order to ensure the visibility of the display device behind the pattern-printed transparent sheet of the present invention, an antireflection film or the like may be provided on the surface or inside of the sheet. The material of the antireflection film is not particularly limited, and those used in the field of normal display transparent sheets 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.

The image display medium on which the pattern-printed transparent sheet of the present invention is mounted is an object that displays various types of 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 display devices such as CRT (cathode ray tube), LCD (liquid crystal display device), PDP (plasma display), EL (electroluminescence) display device, or paper or resin film on which an image is printed. It is. 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.
Information processing devices that handle handwritten input or other information input by other methods include various mobile terminals such as mobile phones and PDAs, personal computers, video phones, televisions with intercommunication functions, Internet terminals, etc. Can be illustrated. Or a book, a brochure, a catalog, a form, an instruction manual, etc. can be illustrated. In the following, a description will be made focusing on a typical usage form, which is installed opposite to the front surface of the screen of the display device and inputs handwritten information on the screen.

The input terminal 6 that can be used in the present invention is not particularly limited as long as it can emit invisible light 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 that does not include ink, graphite, or the like, disclosed in JP 2003-256137 A, an invisible light irradiation unit And a camera incorporating a communication interface such as a wireless transceiver using a CMOS camera, processor, memory, Bluetooth technology, etc., and a battery.
As the operation of the pen-type input terminal 6, when the pen-tip is drawn so that the pen-tip is brought into contact with the front surface of the transparent sheet 1 printed with the dot pattern as shown in FIG. And the CMOS camera is activated to irradiate a predetermined range in the vicinity of the pen tip with invisible light of a predetermined wavelength emitted from the non-visible light irradiation unit, and to image a pattern (pattern imaging) 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 processor, a memory, a wireless transceiver using Bluetooth technology, 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 the code 8 or may transmit the read data wirelessly using radio waves, invisible light, or the like.
In addition, the input terminal 6 may be a reader as described in JP-A-2001-243006.

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.
Further, the read data processing device 7 may be built in the input terminal 6 as disclosed in JP 2003-256137 A, or may be built in an information processing device including a display device. Further, the read data processing device 7 may transmit the position information wirelessly to an information processing device provided with a display device, or may transmit it by a wired connection connected by a code or the like.
The information processing apparatus connected to the display device 5 sequentially updates the images displayed on the display device 5 based on the locus information transmitted from the read data processing device 7, thereby obtaining the locus input by handwriting on the input terminal 6. It can be displayed on the display device as if it were written with a pen on paper.

As described above, the pattern-printed transparent sheet of the present invention can be mounted on an existing display device as it is, and is easier to manufacture than the electrostatic or pressure-sensitive position input device of the type incorporated in the display device. And cost can be reduced. In addition, even if the function of providing location information is reduced because the pattern that can provide printed location information becomes thin or scratched, it is only necessary to replace the transparent sheet, It is easy for the user to handle.
The pattern-printed transparent sheet of the present invention can be used as a liquid crystal protective sheet when mounted on a liquid crystal display. In addition, the pattern-printed transparent sheet of the present invention may be used in a manner other than being placed on the front surface of the display device, such as when used on paper such as an inspection request table (see JP 2004-341831).

The pattern-printed transparent sheet of the present invention can be detachably mounted so as to face the front surface of the display device. In this way, not only one display device but also another display device can be attached. Further, it is preferable that the transparent sheet itself is provided with a mounting means for the display device so that the transparent sheet can be mounted on the display device side without performing processing for mounting. The mounting means may be provided integrally with the transparent sheet or may be provided separately.
Examples of such mounting means include a device that hooks a buckle-shaped object on the corner of the display device, and a device that sandwiches an end of the display device. In the case of mounting on the front surface of the display device, there is a sticking tool that is provided on the contact surface side that comes into contact with the display device and has adhesiveness or adhesiveness for sticking to the display device. Further, examples of the sticking tool include those having adhesiveness or tackiness integrally attached to the transparent sheet, and those including an adhesive or pressure sensitive adhesive directly applied to the contact surface.
Note that, 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 radiation irradiation, heating, etc., and can be peeled again after bonding, is particularly sticky. 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. .

In order to improve the convenience of manufacturing the pattern-printed transparent sheet of the present invention, it is preferable that the transparent sheet is separable. Specific examples include those that can be separated with a cutting tool such as a scissors or a dedicated cutting tool, and those that can be separated by hand by inserting perforations. If this is the case, the user can cut according to the size of the display device owned by each user, so the manufacturer has set several predetermined sizes. This is because a sheet may be manufactured. Further, a perforation may be made in the standard size of a general-purpose display device.
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 an adjacent display device, continuity can be given to input data. Further, by using a plurality of transparent sheets having different coordinate ranges for one input device, different meanings can be given to the respective transparent sheets.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
(1) Preparation of coating solution for infrared reflective transparent pattern Polymerizable acryloyl group at both ends, mesogenic structure at the center, spacer between the acryloyl group and nematic-isotropic transition temperature of 110 ° C Liquid crystal monomer in the vicinity (having two functional groups in the molecule and having the molecular structure represented by the compound (11)) [component (A)] and 100 parts by weight of polymerizable acryloyl group at both ends A methyl isobutyl ketone solution was prepared by dissolving 3 parts by weight of a chiral agent (having two functional groups in the molecule and having a molecular structure represented by the chemical formula (12)) in methyl isobutyl ketone. In this methyl isobutyl ketone solution, 4 parts by weight of a photopolymerization initiator (trade name Lucilin TPO, manufactured by BASF Japan Ltd.) and 0.0054 parts by weight of a leveling agent (trade name BYK361, manufactured by BYK Chemie Corporation) 0.02 part by weight of a polymerization inhibitor (manufactured by Kanto Chemical Co., Inc., trade name BHT) was added to prepare an infrared reflective transparent pattern coating solution.
(2) Preparation of coating solution for ink repellent base 100 parts by weight of pentaerythritol triacrylate (PETA, Nippon Kayaku Co., Ltd., trade name KAYARAD PET-30) and 0.06 parts by weight of leveling agent (BYK361), polymerization 4 parts by weight of an initiator (manufactured by Ciba Specialty Chemicals Co., Ltd., Irgacure 184) was added and mixed, and methyl ethyl ketone was added and adjusted so that the resin content was 50% by mass to prepare an ink repellent base coating solution. .
(3) Preparation of pattern-printed transparent sheet (2) The ink-repellent primer coating solution was applied to a polyethylene terephthalate (PET) substrate with a bar coater to a thickness of 1 μm and cured by ultraviolet irradiation. did. Next, on the substrate, the infrared reflective transparent pattern coating liquid (1) is applied by a gravure printing method with a thickness of 6 to 8 μm and a circular dot pattern having a diameter of 100 μm in plan view. Cured by UV irradiation. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position to the visible light side of 15 nm after 500 hours.

Example 2
(1) Preparation of coating solution for infrared reflective transparent pattern Polymerizable acryloyl group at both ends, mesogenic structure at the center, spacer between the acryloyl group and nematic-isotropic transition temperature of 110 ° C A liquid crystal monomer containing 75 mol% of a liquid crystal monomer (having two functional groups in the molecule and having a molecular structure represented by the compound (11)) [component (A)]; Liquid crystal monomer having an acryloyl group polymerizable only in [a component (B) having one functional group in the molecule] and a liquid crystal monomer having no polymerizable acryloyl group [no functional group in the molecule (C) 100 parts by weight of a liquid crystal compound containing 25 mol% of a component] and a chiral agent having an acryloyl group polymerizable at both ends (the above chemistry having two functional groups in the molecule) A methyl isobryl ketone solution in which 3.1 parts by weight of a compound having a molecular structure represented by the formula (12) was dissolved in methyl isobutyl ketone was prepared. In this methyl isobutyl ketone solution, 4 parts by weight of a photopolymerization initiator (manufactured by BASF Japan Ltd., Lucillin TPO), 0.0054 parts by weight of a leveling agent (BYK361), 0.02 parts by weight of a polymerization inhibitor ( BHT) was added to prepare an infrared reflective transparent pattern coating solution.
(2) Production of pattern-printed transparent sheet A pattern-printed transparent sheet was produced in the same manner as in (1) of Example 1 except that this infrared reflective transparent pattern coating solution was used. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position to the visible light side of 18 nm after 500 hours.

Example 3
(1) Preparation of Infrared Reflective Transparent Pattern Coating Liquid In Example 2 (1), a liquid crystal monomer containing 75 mol% [component (A) having two functional groups in the molecule] and [molecule Instead of 100 parts by weight of a liquid crystal compound containing 25 mol% of (B) component having one functional group in it and [(C) component having no functional group in the molecule], [(A) component] The coating liquid for infrared reflective transparent pattern was similarly used except that the liquid crystal monomer containing 60 mol% and 100 parts by weight of the liquid crystalline compound containing 40 mol% of [Component (B)] and [Component (C)] were used. Was prepared.
(2) Production of pattern-printed transparent sheet A pattern-printed transparent sheet was produced in the same manner as in (1) of Example 1 except that this infrared reflective transparent pattern coating solution was used. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position to the visible light side of 25 nm after 500 hours.

Comparative Example 1
(1) Preparation of Infrared Reflective Transparent Pattern Coating Liquid In Example 2 (1), a liquid crystal monomer containing 75 mol% of [(A) component], [(B) component] and [(C) component In addition to 100 parts by weight of a liquid crystal compound containing 25 mol%, a liquid crystal monomer containing 50 mol% of [Component (A) having two functional groups in the molecule] and [one functional group in the molecule] And (B) component] and [component (C) having no functional group in the molecule] in the same manner except that 100 parts by weight of a liquid crystalline compound containing 50 mol% is used. Was prepared.
(2) Production of pattern-printed transparent sheet A pattern-printed transparent sheet was produced in the same manner as in (1) of Example 1 except that this infrared reflective transparent pattern coating solution was used. When this sheet was stored at 80 ° C., the reflection wavelength peak of the cholesteric liquid crystal shifted from the initial position to the visible light side of 60 nm after 500 hours.

  As described above in detail, the pattern-printed transparent sheet of the present invention can be applied to an application in which various information associated with image information is provided by being installed on the front surface of a medium that displays various image information. In particular, it is suitable as a member for providing coordinate detection means to a data input system of a type that is directly handwritten on the screen of the display device, and in addition to being able to reduce the work space, it is lightweight, mass-produced, and inexpensive. It is easy to increase the area, it is difficult to visually recognize, and the shift of the reflection wavelength of invisible light can be suppressed. For this reason, it can be used easily and has high practical performance. Various information processing such as mobile terminals such as mobile phones and PDAs, personal computers, videophones, televisions equipped with an intercommunication function, Internet terminals, etc. Can be used in equipment.

It is sectional drawing which shows one embodiment of the pattern printing transparent sheet of this invention. It is sectional drawing which shows another 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 the schematic of the whole system using the pattern printing transparent sheet of this invention. 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.

Explanation of symbols

1: Pattern printing transparent sheet (transparent sheet)
2: Transparent substrate 3: Transparent pattern 5: Display device 6: Input terminal (pen type)
7: Reading data processing device 8: Code 21: Base material 22: Underlayer i: Invisible light (incident light)
r: reflected light

Claims (17)

A transparent pattern having a non-visible light reflecting property is printed on the surface of the transparent substrate, and the ink constituting the transparent pattern includes a material that reflects the non-visible light,
The material that reflects invisible light is a liquid crystal material having a fixed cholesteric structure having wavelength selective reflectivity with respect to wavelengths in the invisible light region, and 60 of the liquid crystal materials included in the transparent pattern. A pattern-printed transparent sheet, which is a polyfunctional liquid crystal material in which mol% or more has two or more functional groups.   The pattern-printed transparent sheet according to claim 1, wherein the liquid crystal material having a cholesteric structure is a chiral nematic liquid crystal material obtained by mixing a nematic liquid crystal with a chiral agent.   The pattern-printed transparent sheet according to claim 1, wherein the liquid crystal material having a cholesteric structure is a polymer cholesteric liquid crystal material.   The pattern-printed transparent sheet according to claim 2, wherein the nematic liquid crystal and / or the chiral agent is a compound having an acrylate structure.   The said transparent substrate consists of a base material and the base layer laminated | stacked on the said transparent pattern printing side surface of this base material, and this base layer repels the ink which forms the said transparent pattern. Pattern printing transparent sheet.   The pattern-printed transparent sheet according to claim 1, wherein the transparent pattern is a dot pattern.   The pattern-printing transparent sheet according to claim 1, wherein the transparent pattern has a printing thickness of 1 to 20 μm.   The pattern printing transparent sheet in any one of Claims 1-7 which have a transparentization layer on the said transparent pattern.   The pattern-printed transparent sheet according to claim 1, wherein the invisible light is infrared light or ultraviolet light.   The pattern-printed transparent sheet according to claim 1, wherein the transparent pattern has a selective reflection peak wavelength at 800 to 950 nm.   The pattern-printed transparent sheet according to any one of claims 1 to 9, wherein the transparent pattern has a selective reflection peak wavelength at 200 to 400 nm.   The pattern-printed transparent sheet can provide information on the position of the input terminal on the transparent sheet by reading the reflection pattern of the transparent sheet using an input terminal capable of irradiating and detecting invisible light. Item 12. The pattern-printed transparent sheet according to any one of Items 1 to 11.   The pattern-printed transparent sheet according to claim 12, wherein the pattern-printed transparent sheet is a transparent sheet attached to a display device capable of displaying an image.   The pattern-printed transparent sheet according to claim 13, which is mounted to face the front surface of the display device.   The pattern-printing transparent sheet according to claim 13, further comprising mounting means for mounting on the display device.   The pattern-printed transparent sheet according to claim 15, wherein the attachment means is an attachment tool that is provided on a contact surface side that comes into contact with the display device and has adhesiveness or adhesiveness for attachment to the display device.   The pattern-printed transparent sheet according to claim 1, which is separable.

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