WO2014002731A1

WO2014002731A1 - Front-surface plate for tactile sensor

Info

Publication number: WO2014002731A1
Application number: PCT/JP2013/065812
Authority: WO
Inventors: 健輔藤井; 佐藤　浩二
Original assignee: 旭硝子株式会社
Priority date: 2012-06-25
Filing date: 2013-06-07
Publication date: 2014-01-03
Also published as: JP6076342B2; JPWO2014002731A1

Abstract

Provided is a front-surface plate for a tactile sensor with good sensor accuracy for perceiving by touch, in which any reduction in the external appearance due to an interference pattern is suppressed, light permeability is excellent, and readability is exceptional. A front-surface plate (1) for a tactile sensor comprising a high-resistance layer (3) and an electrically insulating insulation layer (4) layered on a transparent substrate (2) in the stated order from the transparent substrate (2) side, wherein the high-resistance layer (3) has a surface resistance value of 1-100 MΩ/□, a refraction index of 1.8-2.5, and a thickness of 5-50 nm; the insulation layer (4) has a refraction index of 1.3-1.6 and a thickness of 0.5-15 µm; and the transparent substrate (2) has a surface roughness Ra on the surface facing the high-resistance layer (3) of 0.05-0.5 µm. The surface roughness Ra of the surface of the front-surface plate (1) for the tactile sensor is no more than 0.05 µm.

Description

Tactile sensor front plate

The present invention relates to a front plate for a tactile sensor provided on the front surface of a touch panel display device equipped with a so-called tactile sensor that feeds back a tactile sensation to a user's fingertip.

In recent years, as an input device or an input / output device, a touch panel display device (interface device) including a touch panel display that performs an operation by directly touching the touch panel with a finger or the like is used.

A touch panel display device used as an input device or an input / output device can freely configure an input screen by software. Therefore, the touch panel display device has flexibility that cannot be obtained by an input device configured using a mechanical switch. Since it can be compactly configured and has many advantages such as low frequency of mechanical failure, it is now widely used from operation panels of various relatively large machines to very small portable device input / output devices. It's being used.

In many touch panel display devices, the fingertip of the user operating the touch panel touches only a flat and smooth surface to be touched. Therefore, the click feeling felt by the fingertip when operating an input device configured using a mechanical switch. As described above, there is no feedback to the user by touch, which makes the operation feeling of the device unreliable. In order to improve this point, a touch panel display device provided with a so-called tactile sensor that feeds back a tactile sensation to the fingertip of the user who operates it has been proposed (for example, see Patent Document 1). In this touch panel display device, a tactile sensation is generated by a user by vibrating the surface of the touch panel in contact with the fingertip of the user.

By controlling the charge of a protective film or the like (hereinafter referred to as the front plate) provided on the front surface of the touch panel, the tactile sensation is fed back to the user by an electrical sense. The technique to give is also known (for example, refer patent document 2). In Patent Document 2, a predetermined electrical input is applied from a voltage source to conductive electrodes each provided with an insulator to form an electrostatic force (capacitive coupling) in a region between the conductive electrode and the body part. And it generates an electrical sensation.
As such a structure, for example, Non-Patent Document 1 discloses a touch panel in which a transparent electrode laminated on a glass substrate is covered with an insulating layer.

In the apparatus described in Patent Document 2 or Non-Patent Document 1, specifically, as shown in FIG. 1, the voltage and frequency are controlled in a pattern that can reproduce the tactile sensation to be expressed, and the touch panel is touched from a control unit (not shown). It is configured to charge the front plate 101 by energizing a transparent electrode (not shown) of the main body 100 and accumulating charges induced on the front plate 101 side in the layer 103 formed on the transparent substrate 102. Yes. When the sensory receptor X such as a finger is brought into contact with the surface of the front plate 101 in such a charged state, the sensory receptor as a tactile sensation such as a concavo-convex sensation by a weak electrostatic force acting between the two via the insulating layer 104. It is configured to be detected by X.

As a front plate provided in such a touch panel display device equipped with a so-called tactile sensor, the state of charge based on the voltage and frequency sent from the control unit is accurately prevented without interfering with the operation of the transparent electrode provided on the touch panel body. There is a demand for a material that can express a desired tactile sensibility with high reproducibility, and the layer 103 for accumulating charges is required to precisely control the resistance value within a predetermined range. As a material that satisfies such electrical characteristics and has transparency, a layer containing a predetermined metal oxide as a main component, such as niobium oxide or titanium oxide, is used.

However, the layer 103 made of such a metal oxide generally has a refractive index of about 1.8 to 2.5, whereas the insulating layer 104 provided on the upper surface thereof has a refractive index of 1. Since it is about 3 to 1.6, a difference in refractive index tends to occur between them. Therefore, as shown in FIG. 2, reflected light L1 is generated at the interface between the layer 103 and the insulating layer 104, and this reflected light L1 interferes with the reflected light L2 on the surface of the front plate 101. A phenomenon called interference fringes exhibiting a rainbow hue may occur.
When interference fringes occur on the surface of the front plate 101, the appearance of the front plate 101 is deteriorated and the identification of the image displayed on the touch panel body is hindered, and the hue changes due to the shaking or tilt of the front plate 101 itself. Therefore, the visibility as a front plate is reduced.

On the other hand, since the front plate is provided on the front surface of the touch panel body on which an image is projected, from the viewpoint of ensuring visibility, it suppresses the occurrence of white clouding on the front plate surface and is high with respect to light in the visible light range. It is also required to have optical transparency.

JP 2003-288158 A JP 2009-087359 A

The present invention has been made in order to solve the above-described problems. The sensor accuracy sensed by tactile sensation is good, the deterioration of the appearance due to interference fringes is suppressed, the light transmittance is high, and the visibility is excellent. An object is to provide a front plate for a tactile sensor.

The front plate for a tactile sensor of the present invention is a front plate for a tactile sensor in which a high resistance layer and an insulating layer having electrical insulation are laminated in this order from the transparent substrate side on a transparent substrate, The high resistance layer has a surface resistance value of 1 to 100 MΩ / □, a refractive index of 1.8 to 2.5, and a thickness of 5 to 50 nm. The insulating layer has a refractive index of 1.3 to 1. 6. The thickness is 0.5 to 15 μm, the surface roughness Ra of the surface of the transparent substrate on the high resistance layer side is 0.05 to 0.5 μm, and the front surface plate for the tactile sensor is on the insulating layer side The surface roughness Ra of the surface is 0.05 μm or less.

The insulating layer is preferably composed of a layer mainly composed of an organic resin. Moreover, it is preferable that the said high resistance layer consists of a layer which has a metal oxide as a main component. Moreover, it is preferable that a barrier layer is interposed between the transparent substrate and the high resistance layer. Moreover, it is preferable that the said insulating layer is arrange | positioned by the upper surface by which the high resistance layer was contact-processed. Moreover, it is preferable that the front plate for touch sensors has a haze value of 1% or less.

According to the present invention, on the front plate for a tactile sensor in which a high resistance layer and an insulating layer are laminated in this order from the transparent substrate side on the transparent substrate, the sensor accuracy sensed by tactile sense is good, In addition, it is possible to provide a front plate for a tactile sensor that is suppressed in appearance deterioration due to interference fringes, has high light transmittance, and is excellent in visibility.

The schematic diagram which shows the state which the fingertip adjoined to the touchscreen surface provided with the front plate for touch sensors. FIG. 2 is a schematic cross-sectional view showing a state in which external light is incident on the tactile sensor front plate shown in FIG. The typical sectional view showing an example of the front board for touch sensors of the present invention. Sectional drawing which expands and shows a part of front plate for touch sensors shown in FIG. FIG. 4 is a schematic cross-sectional view showing a state in which the touch sensor front plate shown in FIG. 3 is stacked above the touch panel body. The typical sectional view showing another example of the front board for touch sensors of the present invention. The typical sectional view showing another example of the front board for touch sensors of the present invention. The figure which shows the spectral reflectance of the front plate for touch sensors of Example 1. FIG. The figure which shows the spectral reflectance of the front plate for touch sensors of Example 3. The figure which shows the spectral reflectance of the front plate for touch sensors of Example 6. FIG. The figure which shows the spectral transmittance | permeability of the front plate for touch sensors of Example 1. FIG. The figure which shows the spectral transmission factor of the front plate for touch sensors of Example 6. FIG.

Hereinafter, embodiments of a front plate for a touch sensor according to the present invention will be described with reference to the drawings. However, the front plate for a touch sensor of the present invention is not limited to this.
FIG. 3 is a schematic cross-sectional view showing an example of a front plate for a tactile sensor according to an embodiment of the present invention, FIG. 4 is a cross-sectional view showing a part thereof enlarged, and FIG. 5 is a front view for the tactile sensor. It is typical sectional drawing which shows the state which laminated | stacked the face plate on the upper side of the touch-panel main body. 6 and 7 are schematic cross-sectional views showing another example and still another example of the front plate for a tactile sensor according to the embodiment of the present invention, respectively.

In the touch sensor front plate 1 according to the embodiment of the present invention, a high resistance layer 3 and an insulating layer 4 are laminated in this order on a transparent substrate 2.

The front plate 1 for the tactile sensor has a surface resistance value of the high resistance layer 3 of 1 to 100 MΩ / □, a refractive index of 1.8 to 2.5, a thickness of 5 to 50 nm, and a refractive index of the insulating layer 4. 1.3 to 1.6, the thickness is 0.5 to 15 μm, the surface roughness Ra of the surface S1 on the high resistance layer 3 side of the transparent substrate 2 is 0.05 to 0.5 μm, and the front plate for a tactile sensor The surface roughness Ra of the surface on the insulating layer 4 side of 1 is 0.05 μm or less.

As used herein, “refractive index” refers to a refractive index measured using a light beam having a wavelength of 550 nm at 20 ° C. unless otherwise specified.
In the present specification, the “surface roughness Ra” is the arithmetic average roughness Ra, and the value of the arithmetic average roughness Ra is defined in JIS B0601 (1994) 3 “Definition of defined arithmetic average roughness. And display ".
The “thickness” of each layer in the present specification is a thickness obtained by measuring with a stylus type surface roughness measuring machine.

Further, in this specification, the “surface on the insulating layer 4 side of the front plate 1 for tactile sensor” refers to the surface of the outermost layer on the insulating layer side of the front plate for tactile sensor. For example, in FIG. It means the surface S2 including the insulating layer 4 of the front plate 1 for use. When the functional layer such as the water-repellent layer 6 is further provided on the insulating layer 4 as shown in FIG. 6, the surface on the insulating layer 4 side of the front panel 1 for the touch sensor is a functional layer constituting the outermost layer, for example, FIG. 6 is a surface S5 including the water repellent layer 6 of the front plate 1 for the touch sensor. In other words, the “surface on the insulating layer 4 side of the front plate 1 for tactile sensor” means the surface opposite to the surface S4 on the transparent substrate 2 side of the front plate 1 for tactile sensor, that is, the side on which the touch panel is provided. The surface opposite to the surface (see FIG. 5). In the present specification, the surface on the insulating layer side of the front plate for a touch sensor may be referred to as “the surface of the front plate for a touch sensor”.

According to the touch sensor front plate 1 of the embodiment of the present invention, the surface roughness Ra of the surface S1 on the high resistance layer 3 side of the transparent substrate 2 is set to 0.05 to 0.5 μm, for example, in FIG. The reflected light generated at the interface between the insulating layer 104 and the layer 103 and the reflected light generated on the surface of the front plate 101 interfere with each other and the reflected light exhibits a rainbow hue. Interference fringes can be suppressed.

Further, according to the front plate 1 for a tactile sensor of the embodiment of the present invention, the surface roughness Ra of the surface of the front plate 1 for the tactile sensor is set to 0.05 μm or less, thereby causing white clouding or the like on the surface of the front plate 1. A front plate for a tactile sensor that can suppress a decrease in light transmittance and has excellent visibility can be obtained.

The transparent substrate 2 is used without particular limitation as long as the surface roughness Ra of the surface S1 on the high resistance layer 3 side is 0.05 to 0.5 μm and can transmit light in the visible light region. be able to. For example, as shown in FIG. 4, the interface S3 on the insulating layer 4 side of the high resistance layer 3 laminated on the transparent substrate 2 usually reflects the shape of the surface S1 of the transparent substrate 2 on the high resistance layer 3 side. Has the shape.

By setting the surface roughness Ra of the surface S1 on the high resistance layer 3 side of the transparent substrate 2 to 0.05 μm or more, for example, as shown in FIG. 4, the light L3 incident from the surface S2 of the front plate 1 for tactile sensor is At the interface S3 between the insulating layer 4 and the high resistance layer 3 reflecting the shape of the surface S1 on the high resistance layer 3 side of the transparent substrate 2, the reflected light L4 is generated by being diffusely reflected. Since the reflected light L4 is diffusely reflected light that is reflected in various directions, the reflected light L4 hardly interferes with the reflected light L5 on the surface S2 of the front plate 1 for tactile sensors, and thus the generation of interference fringes is suppressed. The For this reason, it can be set as the tactile sensor front plate 1 having a good appearance without the reflected light exhibiting a rainbow hue.

On the other hand, when the surface roughness Ra of the surface S1 on the high resistance layer 3 side of the transparent substrate 2 exceeds 0.5 μm, the convex portion is insulated at the interface S3 on the insulating layer 4 side of the high resistance layer 3 reflecting the shape. For example, when the front panel 1 for a tactile sensor is used as shown in FIG. 5, a sense of approaching to the surface S2 of the front panel 1 for a tactile sensor is likely to occur. There is a possibility that a current based on the charge accumulated in the high resistance layer 3 directly flows into the receptor X. When the surface roughness Ra of the surface S1 of the transparent substrate 2 on the high resistance layer 3 side exceeds 0.5 μm, the transparent substrate 2 and the surface S1 of the transparent substrate 2 on the high resistance layer 3 side are directly laminated. In the example shown in FIG. 3, for example, the adhesion with the high resistance layer 3 is lowered, and the shape stability as the front plate for the tactile sensor may be lowered. The surface roughness Ra of the surface S1 on the high resistance layer 3 side of the transparent substrate 2 is preferably 0.07 to 0.2 μm, more preferably 0.08 to 0.15 μm.

Specific examples of the transparent substrate 2 include colorless and transparent soda lime silicate glass, aluminosilicate glass (SiO ₂ —Al ₂ O ₃ —Na ₂ O glass), lithium aluminosilicate glass, quartz glass, and alkali-free. Glass, transparent glass plate made of other various glasses, plastic film consisting of a single layer of plastic material selected from polyethylene terephthalate, polycarbonate, triacetyl cellulose, polyethersulfone, polymethyl methacrylate, cycloolefin polymer, etc. A plastic film such as a laminated film obtained by laminating two or more layers of plastic materials selected from the above can be used.

Surface treatment with a surface roughness Ra of 0.05 to 0.5 μm on one main surface of a glass plate or plastic film made of soda lime silicate glass or the like, for example, frost treatment on a glass plate By performing, the transparent base | substrate 2 which has the surface surface-treated in the range of the said surface roughness Ra as surface S1 by the side of the high resistance layer 3 can be obtained.

The frost treatment can be performed, for example, by immersing a glass plate, which is an object to be processed, in a mixed solution of hydrogen fluoride and ammonium fluoride and chemically treating the immersion surface.
In addition to such a chemical treatment method, for example, a so-called sand blasting method in which crystalline silicon dioxide powder, silicon carbide powder or the like is blown onto the glass plate surface with pressurized air, crystalline silicon dioxide powder, silicon carbide, etc. It is also possible to use a method based on physical treatment such as polishing with a brush moistened with water using a brush to which powder or the like is adhered.
In particular, the method of chemically surface-treating using a chemical solution such as hydrogen fluoride is preferable because microcracks are hardly generated on the surface of the object to be processed, and mechanical strength is not easily lowered.

As the transparent substrate 2, it is preferable to use a soda lime silicate glass plate from the viewpoint of adhesion with a layer directly provided on the surface S 1 on the high resistance layer 3 side. Further, from the viewpoint of the strength of the transparent substrate 2 itself, it is preferable to use a tempered glass plate (for example, “Dragon Trail (registered trademark)”) obtained by strengthening an aluminosilicate glass plate.

Considering the usage pattern of the front plate 1 for a tactile sensor, the transparent substrate 2 is required to have sufficient strength to withstand a certain amount of pressing force. From such a viewpoint, it is preferable to use as the transparent substrate 2 a tempered glass plate obtained by strengthening an aluminosilicate glass plate.

As a glass material constituting the aluminosilicate glass plate, for example, a glass material having the following composition is used. The composition expressed in mol% is SiO ₂ 50-50%, Al ₂ O ₃ 1-20%, Na ₂ O 6-20%, K ₂ O 0-11%, MgO 0-15%. , A glass material containing 0-6% CaO and 0-5% ZrO ₂ .

A compressive stress layer is formed on the surface of the tempered glass plate obtained by strengthening the aluminosilicate glass plate, and the thickness of the compressive stress layer is preferably 10 μm or more, more preferably 30 μm or more. Further, the surface compressive stress in the compressive stress layer is preferably 200 MPa or more, and more preferably 550 MPa or more.

As the strengthening treatment for the aluminosilicate glass plate, chemical strengthening treatment is preferable. As a method for performing chemical strengthening treatment, typically, a method in which an aluminosilicate glass plate is immersed in KNO ₃ molten salt, subjected to ion exchange treatment, and then cooled to around room temperature. The processing conditions such as the temperature and immersion time of the KNO ₃ molten salt may be set so that the surface compressive stress and the thickness of the compressive stress layer have desired values.

The thickness of the transparent substrate 2 is not particularly limited, but when the transparent substrate 2 is composed of the glass plate described above, it is preferably 0.1 to 2 mm, more preferably 0.3 to 1 mm. When the thickness of the transparent substrate 2 is 2 mm or less, the pressing force against the surface of the touch sensor front plate 1 is easily transmitted to the lower panel body, and the operability is good. When the transparent substrate 2 is composed of the above-described plastic film, the thickness is preferably 50 to 500 μm, more preferably 50 to 200 μm. The transparent substrate 2 may be composed of a single layer or may be composed of a plurality of layers.

As the transparent substrate 2, one having a haze value of 5 to 30% is preferably used, and one having a haze value of 10 to 27% is more preferably used.
By setting the haze value of the transparent substrate 2 to 30% or less, the front plate 1 for a tactile sensor is sufficiently secured to have light transmission as the front plate 1 for a tactile sensor and the occurrence of dielectric breakdown is suppressed. be able to. Further, by setting the haze value of the transparent substrate 2 to 5% or more, formation of interference fringes due to reflected light is suppressed, and the front panel 1 for a tactile sensor having a good appearance can be obtained.

Here, the haze value is an index of turbidity, and the ratio of the diffuse transmitted light to the total transmitted light, that is, the total transmittance T when the sample is irradiated with light from the light source, and scattered in the sample. The haze value H = S / T × 100 is obtained from the light transmittance S.

The high resistance layer 3 is a layer having a surface resistance value of 1 to 100 MΩ / □, a refractive index of 1.8 to 2.5, and a thickness of 5 to 50 nm. For example, as shown in FIG. 5, the touch sensor front plate 1 is used by being laminated with a touch panel body 5 including a transparent electrode 5a. Lamination is performed such that the surface S4 on the transparent substrate 2 side of the front plate 1 for touch sensor faces the transparent electrode 5a of the touch panel body 5. In this way, the high resistance layer 3 in the touch sensor front plate 1 used by being laminated with the touch panel body 5 is induced to the touch sensor front plate 1 side by energizing the transparent electrode 5 a of the touch panel body 5. It functions as a layer for accumulating the accumulated charges.

The configuration of the high resistance layer 3 is not particularly limited as long as it is a layer having a surface resistance value, a refractive index, and a thickness in the above ranges. The high resistance layer 3 is a layer provided directly (see FIG. 3) or via another functional layer such as the barrier layer 7 (see FIG. 7) on the surface S1 having the surface roughness Ra in the above range of the transparent substrate 2. It is. In any case, the surface S3 of the high resistance layer 3 opposite to the transparent substrate 2 is formed to have a shape that sufficiently reflects the surface shape of the surface S1 of the transparent substrate 2 on the high resistance layer 3 side. Is preferred. As the high resistance layer 3, a layer containing a metal oxide as a main component, for example, a layer containing tin oxide and titanium oxide as main components, or a layer containing niobium oxide and titanium oxide as main components can be suitably used.

The layer containing tin oxide and titanium oxide as a main component may contain a composite oxide of tin and titanium. In addition, the layer containing niobium oxide and titanium oxide as main components may contain a composite oxide of niobium and titanium.
In this specification, for example, “a layer containing a metal oxide as a main component” refers to a layer containing a metal oxide at a ratio of 95 mass% or more.

By setting the surface resistance value of the high-resistance layer 3 to 1 MΩ / □ or more, the high-resistance layer 3 and the transparent electrode 5a are electrically operated when the transparent electrode 5a of the touch panel body 5 is energized, and the touch panel body 5 It is possible to prevent the operation from being hindered. In addition, by setting the surface resistance value of the high resistance layer 3 to 100 MΩ / □ or less, the charged state based on the control voltage and the frequency is accurately expressed, and the desired tactile sensation is expressed in the sensory receptor X with high reproducibility. And excellent sensor accuracy by tactile sensation can be obtained. The surface resistance value of the high resistance layer 3 is preferably 5 to 60 MΩ / □.

As the high resistance layer 3, a layer containing tin oxide and titanium oxide as main components controls the surface resistance value within the above desired range while ensuring good luminous transmittance and low luminous reflectance. Since it is easy, it is used suitably.

The refractive index of the high resistance layer 3 is 1.8 to 2.5 as described above.
The constituent material of the high resistance layer 3 is required to have a desired resistance value and light transmittance. A constituent material that can satisfy these characteristics usually has a refractive index of 1.8 to 2.5. A more preferable constituent material satisfying the above characteristics is a material having a refractive index of 2.0 to 2.5.

On the other hand, for example, the viewpoint of suppressing the generation of interference fringes caused by the interference between the reflected light L4 at the interface S3 between the high resistance layer 3 and the insulating layer 4 shown in FIG. 4 and the reflected light L5 at the surface S2 of the front plate 1 for tactile sensors. Therefore, it is desirable that the refractive index of the high resistance layer 3 is close to the refractive index of the insulating layer 4. However, as described above, the refractive index of the constituent material that can be selected as the high resistance layer 3 from the viewpoint of the resistance value and the light transmittance is limited to the above range, and by adjusting the refractive index of the high resistance layer 3 itself. It is practically difficult to reduce the refractive index difference between the insulating layer 4 and the high resistance layer 3 to a level that can suppress the occurrence of interference fringes. Therefore, in the present invention, as described above, the surface roughness Ra of the surface S1 on the high resistance layer 3 side of the transparent substrate 2 is set to 0.05 to 0.5 μm so that this shape is insulated from the high resistance layer 3. Reflecting on the interface S3 with the layer 4, the generation of interference fringes is suppressed.

The layer containing tin oxide and titanium oxide as main components, or the layer containing niobium oxide and titanium oxide as main components contains tin oxide and titanium oxide or niobium oxide and titanium oxide as main components, and serves as the high resistance layer 3. Other elements such as Al, Si, Ga, and In may be included as long as the function is not impaired.

The high resistance layer 3 is a glass plate or plastic film that has been surface-treated so that the surface roughness Ra is in the above range by sputtering such as DC (direct current) sputtering, AC (alternating current) sputtering, and RF (high frequency) sputtering. It can form on the surface treatment surface of the transparent base | substrate 2 which consists of these. Among these, the sputtering method by DC magnetron sputtering is preferably used because the process is stable and film formation on a large area is easy.

Note that DC magnetron sputtering includes pulsed (applying voltage in the form of a pulse wave) DC magnetron sputtering. Pulsed DC magnetron sputtering is effective in preventing abnormal discharge.

The high resistance layer 3 includes two or more metal elements such as the above-described layer containing tin oxide and titanium oxide as a main component, and has the desired surface resistance value while having good light transmittance. It is suitable because it is easy to control within the range. For the formation of such a high resistance layer 3, so-called co-sputtering using a plurality of targets made of a single element can be used.

For example, when a layer containing tin oxide and titanium oxide as main components is formed by a co-sputtering method, a target containing tin as a main component and a target containing titanium as a main component are used.
As a metal target mainly composed of tin, a metal target composed solely of tin, or containing tin as a main component, and a known dopant such as a metal other than tin, for example, Al, Si, or the like, as long as the characteristics of the present invention are not impaired. Doped ones can be used.
As the metal target containing titanium as a main component, a target made of only titanium or a material containing titanium as a main component and doped with a known dopant other than titanium within a range not impairing the characteristics of the present invention can be used. .

For example, when a layer containing niobium oxide and titanium oxide as main components is formed by a co-sputtering method, a target containing niobium as a main component and a target containing titanium as a main component are preferably used.
As a metal target mainly composed of niobium, a metal target composed of niobium alone or a material containing niobium as a main component, and a known dopant such as a metal other than niobium, such as Al and Si, does not impair the characteristics of the present invention. Doped ones can be used.

Various reactive gases can be used as the sputtering gas. Specifically, for example, a mixed gas of oxygen gas and inert gas, a mixed gas of oxygen gas, nitrogen gas, and inert gas, or the like can be used.
Examples of the inert gas include rare gases such as helium, neon, argon, krypton, and xenon. Among these, argon is preferable from the viewpoint of economy and ease of discharge. These may be used alone or in admixture of two or more.
In addition to the nitrogen gas (N ₂ ), N ₂ O, NO, NO ₂ , NH ₃ or the like can be used as the sputtering gas as a gas containing nitrogen atoms.

The partial pressure of the gas containing oxygen gas, inert gas, and nitrogen atom in the sputtering gas, and the total pressure of the sputtering gas are not particularly limited, and may be any pressure at which glow discharge is stably performed.

When sputtering is performed, the power density is preferably 0.9 to 4 W / cm ^{2 and} more preferably 0.9 to 3 W / cm ² . The film formation time may be determined according to the film formation speed and the desired film thickness.

Note that co-sputtering is performed by discharging each target simultaneously, and a film having a desired composition can be formed by controlling the power density applied to each target and the partial pressure of the sputtering gas. .

The high resistance layer 3 is formed by using, for example, a physical vapor deposition method other than a sputtering method such as a vacuum vapor deposition method, an ion beam assisted vapor deposition method or an ion plate method, or a chemical vapor deposition method such as a plasma CVD method. Can also be done. Since it is easy to obtain a uniform film thickness with a large area, a sputtering method is preferably used.

When the high-resistance layer 3 is a layer containing tin oxide and titanium oxide as main components, the high-resistance layer 3 contains 1 to 30 atomic percent of Ti with respect to the total amount (100 atomic percent) of Sn and Ti. A layer containing 5 to 20 atom% is more preferable. In the case where the high resistance layer 3 is a layer containing niobium oxide and titanium oxide as main components, the high resistance layer 3 has a Ti content of 90 to 99 with respect to the total amount (100 atomic%) of Nb and Ti. A layer containing 0.9 atomic% is preferable, and a layer containing 95 to 99.9 atomic% is more preferable.
By setting the atomic ratio in the high resistance layer 3 within the above range, the surface resistance value in the desired range can be easily obtained in the high resistance layer 3, and the refractive index in the desired range can be obtained. it can.

The thickness of the high resistance layer 3 is 5 nm or more and 50 nm or less, more preferably 5 nm or more and 30 nm or less. By setting the thickness of the high resistance layer 3 to 5 nm or more, a sufficient charge holding function can be obtained. On the other hand, when the thickness of the high resistance layer 3 exceeds 50 nm, the shape of the surface S1 having the surface roughness Ra in the above range in the transparent substrate 2 is the surface opposite to the transparent substrate 2 side of the high resistance layer 3, that is, the insulation. It is not sufficiently reflected on the interface S3 with the layer 4, and the effect of diffusing the reflected light L4 generated at the interface S3 cannot be sufficiently obtained. By setting the thickness of the high-resistance layer 3 to 5 nm or more and 50 nm or less, the front plate 1 for a tactile sensor having a good external appearance with suppressed interference fringes while ensuring a sufficient charge holding function is obtained. Can do.

In addition, the thickness of the high resistance layer 3 can be appropriately adjusted depending on the film forming speed and the substantial film forming time when performing sputtering.

The insulating layer 4 is a layer provided on the upper surface of the high-resistance layer 3 or another layer on the high-resistance layer 3, for example, when used as shown in FIG. 5 for a tactile sensor It has a function of preventing a current based on charges accumulated in the high resistance layer 3 from directly flowing into the sensory receptor X such as a fingertip that touches the surface S2 of the front plate 1.

In this specification, the insulating layer 4 refers to a layer having a volume resistance value of 10 ¹⁰ Ω · cm or more. Here, the volume resistance value is a value measured according to JIS C2318 (1975).

The insulating layer 4 has a refractive index of 1.3 to 1.6, and a more preferable constituent material that can be applied to the insulating layer 4 has a refractive index of 1.4 to 1.6. The insulating layer 4 has a refractive index of 1.3 to 1.6 when a constituent material is selected in consideration of electrical insulation, light transmittance, ease of formation of the insulating layer 4, and the like. The thickness of the insulating layer 4 is in the range of 0.5 to 15 μm.

The insulating layer 4 is not particularly limited as long as it has the above-described refractive index and has a light transmitting property and an electrical insulating property when the layer is formed with a thickness in the above range. As the insulating layer 4, for example, (I) a composition for forming an insulating layer (i) containing an ultraviolet curable component and adjusted to satisfy the characteristics of the insulating layer 4 when the layer is formed from the obtained cured product (i) ) Was cured with ultraviolet rays, or (II) containing a thermosetting component, and (I) was adjusted so as to satisfy the characteristics of the insulating layer 4 when a layer was formed from the obtained cured product. A layer made of a cured product obtained by curing the insulating layer forming composition (ii) with heat can be used.

Here, the insulating layer forming compositions (i) and (ii) may contain a volatile component such as an organic solvent which volatilizes when forming the layer. In the insulating layer forming compositions (i) and (ii), the component that actually forms the insulating layer other than the volatile component is referred to as solid content. The solid content may contain a non-curable component in addition to the curable component. Therefore, the “cured product” obtained by curing the insulating layer forming compositions (i) and (ii) is a cured product of a curable component and a non-cured product formed from a solid content contained in the composition. The thing which consists of a sclerosing | hardenable component.

The insulating layer 4 is preferably a layer containing an organic resin as a main component. That is, when the insulating layer 4 is made of a cured body as described above, the cured body preferably contains an organic resin as a main component. In this specification, “a layer containing an organic resin as a main component” refers to a layer containing an organic resin at a ratio of 95% by mass or more.

The organic resin is preferably one or more selected from acrylic resins, epoxy resins, silicone resins and the like. Among these, acrylic resins are particularly preferable. Examples of the acrylic resin include acrylic resin, urethane acrylate resin, epoxy acrylate resin, polyester acrylate, and polyether acrylate.

The organic resin used for the insulating layer 4 may be a cured product of an ultraviolet curable component or a cured product of a thermosetting component. The organic resin is preferably a cured product of an ultraviolet curable component. Therefore, the ultraviolet curable component contained in the insulating layer forming composition (i) is preferably a component that is cured to become an organic resin, particularly an acrylic resin.
Further, the thermosetting component contained in the insulating layer forming composition (ii) may be a component that is cured to become an organic resin, and has a main skeleton due to a siloxane bond by curing such as organosilane. It may be a component that gives a cured product.

Hereinafter, the components in the insulating layer forming composition (i) and the insulating layer forming composition (ii) and the method for forming the insulating layer 4 using the composition will be described. In the following, for the insulating layer forming composition (i), the insulating layer forming composition (ii) is cured by curing, using as an example a component containing an organic resin, particularly an acrylic resin. Although an example including a component that gives a cured product having a main skeleton by a siloxane bond will be described, the present invention is not limited to this.

[Insulating layer forming composition (i)]
Examples of the insulating layer forming composition (i) include the following ultraviolet curable polymerizable compound (A) (hereinafter referred to as “polymerizable compound (A)”), ultraviolet absorber (B) and light. What contains a polymerization initiator (C) can be used.

Here, the polymerizable compound (A) may be a monomer or a (co) oligomer or pre (co) polymer in which one or more of them are polymerized as long as they have ultraviolet curing properties. Good.

At least a part of the polymerizable compound (A) is a polyfunctional polymerizable compound (a-1) having two or more acryloyl groups or methacryloyl groups in one molecule (hereinafter referred to as polymerizable compound (a-1)). .). Hereinafter, a (meth) acrylol group is used as a term meaning both polymerizable functional groups of an acryloyl group and a methacryloyl group. The same applies to terms such as (meth) acrylate and (meth) acrylic acid.

As the polymerizable functional group, an acryloyl group is preferred because of its high polymerizability, particularly high polymerizability by ultraviolet rays. Accordingly, preferred compounds having the (meth) acryloyl group are compounds having an acryloyl group. Similarly, in (meth) acrylate, (meth) acrylic acid and the like, a compound having an acryloyl group is preferable. In one molecule of a compound having two or more (meth) acryloyl groups, the polymerizable functional group may be different, that is, it may contain one or more acryloyl groups and one or more methacryloyl groups. Are those in which all polymerizable functional groups are acryloyl groups.

Examples of the polymerizable compound (A) other than the polymerizable compound (a-1) include a monofunctional polymerizable compound having one (meth) acryloyl group in one molecule (hereinafter referred to as “polymerizable compound (a-2)”). And a polymerizable compound having one or more ultraviolet curable polymerizable functional groups other than (meth) acryloyl groups.

When the UV-curable polymerizable functional group is a (meth) acryloyl group, the UV-curing property is sufficient and it is easily available, so that a polymerizable compound other than the polymerizable compound (a-1) (A ) Is preferably a polymerizable compound (a-2). Accordingly, the polymerizable compound (A) is preferably composed of at least one compound having a (meth) acryloyl group substantially including the polymerizable compound (a-1). Hereinafter, all the polymerizable compounds (A) including the polymerizable compound (a-1) are described as compounds having a (meth) acryloyl group, that is, an organic resin obtained by curing is an acrylic resin. To do.

The polymerizable compound (A) may be a compound having various functional groups and bonds in addition to the (meth) acryloyl group. For example, it may have a hydroxyl group, a carboxyl group, a halogen atom, a urethane bond, an ether bond, an ester bond, a thioether bond, an amide bond, or the like. In particular, a (meth) acryloyl group-containing compound having a urethane bond (hereinafter referred to as “acrylic urethane”) and a (meth) acrylic acid ester compound having no urethane bond are preferable.

The polymerizable compound (a-2) is usually a compound having no urethane bond, but the polymerizable compound (a-2) is not limited to a compound having no urethane bond. On the other hand, the polymerizable compound (a-1) may or may not have a urethane bond. The average number of (meth) acryloyl groups per molecule of the polymerizable compound (a-1) is not particularly limited, but is preferably 2 to 50, and more preferably 2 to 30.

Acrylic urethane is a reaction between a compound having a (meth) acryloyl group and a hydroxyl group and a compound having an isocyanate group, a compound having a (meth) acryloyl group and an isocyanate group and a (meth) acryloyl group and having two or more hydroxyl groups Or a compound having a (meth) acryloyl group and a hydroxyl group and a compound having two or more isocyanate groups (hereinafter referred to as “polyisocyanate”). And a hydroxyl group-containing compound.

Two or more (meth) acryloyl groups, hydroxyl groups and isocyanate groups may be present in each molecule in each of the above-mentioned compounds which are raw materials for acrylic urethane. In the acrylic urethane obtained by these reactions, a hydroxyl group may be present but an isocyanate group is preferably absent.

In addition, as a hydroxyl-containing compound, a high molecular weight polyol, a hydroxyl-containing vinyl polymer, etc. are mentioned compared with a polyhydric alcohol or a polyhydric alcohol. These hydroxyl group-containing compounds may be used alone or in combination of two or more.

A preferred acrylic urethane as the polymerizable compound (a-1) is preferably a reaction product of a hydroxyl group-containing (poly) pentaerythritol poly (meth) acrylate and a polyisocyanate.
The (poly) pentaerythritol in the above (poly) pentaerythritol poly (meth) acrylate means a pentaerythritol multimer such as pentaerythritol or dipentaerythritol, or a mixture containing them as a main component. The degree is preferably about 1 to 4, particularly about 1.5 to 3. The poly (meth) acrylate in the (poly) pentaerythritol poly (meth) acrylate is an ester having two or more (meth) acryloyl groups, and an average of about 3 to 6 (meth) acryloyl per molecule. Compounds having a group are preferred. The (poly) pentaerythritol poly (meth) acrylate used for producing the acrylic urethane has an average of about 1 or more hydroxyl groups per molecule.
In addition, the average number of (meth) acryloyl groups per molecule in the acrylic urethane which is a reaction product of the hydroxyl group-containing (poly) pentaerythritol poly (meth) acrylate and polyisocyanate is 4 or more, particularly 8 to 20 preferable.

The polymerizable compound (a-1) containing no urethane bond is preferably a (meth) acrylate of a hydroxyl group-containing compound or a (meth) acrylic acid adduct of a polyepoxide. Examples of the hydroxyl group-containing compound include polyhydric alcohols and high molecular weight polyols as described above. Specific examples of the polymerizable compound (a-1) not containing a urethane bond include the following compounds.

(Meth) acrylates of the following aliphatic polyhydric alcohols. 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, di (meth) acrylate of long chain aliphatic diol having 14 to 15 carbon atoms 1,3-butanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, triglycerol di (meth) acrylate, Trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol Sa (meth) acrylate, dipentaerythritol penta (meth) acrylate, di (meth) acrylate of a diol comprising a condensate of neopentyl glycol and trimethylol propane.

(Meth) acrylate of polyhydric alcohol or polyhydric phenol having the following aromatic nucleus or triazine ring. Bis (2- (meth) acryloyloxyethyl) bisphenol A, bis (2- (meth) acryloyloxyethyl) bisphenol S, bis (2- (meth) acryloyloxyethyl) bisphenol F, tris (2- (meth) acryloyl) Oxyethyl) isocyanurate, bisphenol A di (meth) acrylate.

(Meth) acrylate of the following hydroxyl group-containing compound-alkylene oxide adduct, (meth) acrylate of the hydroxyl group-containing compound-caprolactone adduct, and (meth) acrylate of polyoxyalkylene polyol. In the following, EO represents ethylene oxide, PO represents propylene oxide, and [] represents the molecular weight of the polyoxyalkylene polyol. Trimethylolpropane-EO adduct tri (meth) acrylate, trimethylolpropane-PO adduct tri (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (Meth) acrylate, dipentaerythritol-caprolactone adduct hexa (meth) acrylate, tris (2-hydroxyethyl) isocyanurate-caprolactone adduct tri (meth) acrylate, polyethylene glycol [200-1000] di (meth) Acrylate, polypropylene glycol [200-1000] di (meth) acrylate.

Carboxylic acid ester and phosphoric acid ester having the following (meth) acryloyl group. Bis (acryloyloxyneopentyl glycol) adipate, di (meth) acrylate of hydroxypivalic acid neopentyl glycol ester, di (meth) acrylate of hydroxypivalic acid neopentyl glycol ester-caprolactone adduct, bis (2- (meth) acryloyl) Oxyethyl) phosphate, tris (2- (meth) acryloyloxyethyl) phosphate.

(Meth) acrylic acid adducts of the following polyepoxides (with one molecule of (meth) acrylic acid added per one epoxy group of the polyepoxide), and glycidyl (meth) acrylate and a polyhydric alcohol or polycarboxylic acid The reaction product of the above (however, two or more molecules of glycidyl (meth) acrylate reacted per molecule such as polyhydric alcohol). (Meth) acrylic acid adduct of bisphenol A-diglycidyl ether, vinylcyclohexene dioxide- (meth) acrylic acid adduct, dicyclopentadiene dioxide- (meth) acrylic acid adduct, glycidyl (meth) acrylate and ethylene glycol Reaction product of glycidyl (meth) acrylate and propylene glycol, reaction product of glycidyl (meth) acrylate and diethylene glycol, reaction product of glycidyl (meth) acrylate and 1,6-hexanediol, glycidyl (meta ) Reaction product of acrylate and glycerol, reaction product of glycidyl (meth) acrylate and trimethylolpropane, reaction product of glycidyl (meth) acrylate and phthalic acid.

Alkyl-modified dipentaerythritol penta (meth) acrylate, alkyl-modified dipentaerythritol tetra (meth) acrylate, which is an alkyl etherified product of the above-mentioned (meth) acrylates and having an unreacted hydroxyl group, Alkyl-modified dipentaerythritol tri (meth) acrylate. The following compounds are similarly applied to the term “modification” in the alkenyl etherified product, carboxylic acid esterified product and the like of the above (meth) acrylates and compounds having an unreacted hydroxyl group. Allyl etherified product of vinylcyclohexene dioxide- (meth) acrylic acid adduct, methyl etherified product of vinylcyclohexene dioxide- (meth) acrylic acid adduct, stearic acid-modified pentaerythritol di (meth) acrylate.

A preferable example of the polymerizable compound (a-1) which is a polyester having no urethane bond and having two or more (meth) acryloyl groups is (poly) pentaerythritol poly (meth) acrylate as described above. In this case, (poly) pentaerythritol poly (meth) acrylate is a compound having an average of two or more (meth) acryloyl groups per molecule, and may or may not have a hydroxyl group. The degree of multimerization of the (poly) pentaerythritol moiety is preferably about 1 to 4, and more preferably 1.5 to 3. Further preferred (poly) pentaerythritol poly (meth) acrylate is (poly) pentaerythritol poly (meth) acrylate in which substantially all hydroxyl groups of (poly) pentaerythritol are converted to (meth) acryloyloxy groups.

The monofunctional polymerizable compound having one (meth) acryloyl group per molecule as the polymerizable compound (a-2) may have a functional group such as a hydroxyl group or an epoxy group. A preferred polymerizable compound (a-2) is (meth) acrylic acid ester, that is, (meth) acrylate.

Specific examples of the polymerizable compound (a-2) include the following compounds. Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) Acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, 1,4- (Meth) acrylic acid adducts of butylene glycol mono (meth) acrylate, ethoxyethyl (meth) acrylate, and phenylglycidyl ether.

In many cases, it is preferable to use two or more polymerizable compounds (a-1). Among them, one or more polymerizable compounds (a-1) are compounds having 2 to 3 (meth) acryloyl groups, and the other one or more are compounds having a large number of (meth) acryloyl groups. Preferably there is. The former polymerizable compound (a-1) is preferably a compound having two (meth) acryloyl groups.

The total ratio of the polymerizable compound (a-1) in the polymerizable compound (A) is preferably 20 to 100% by mass, particularly preferably 50 to 100% by mass, and further preferably 70 to 100% by mass. When the ratio of the polymerizable compound (a-1) is within this range, the scratch resistance is sufficient.

Part or all of the ultraviolet absorber (B) is composed of a polymerizable ultraviolet absorber (b-1). When the amount of the ultraviolet absorber (B) is small, the entire amount is usually composed of the polymerizable ultraviolet absorber (b-1). In the insulating layer forming composition (i), the ratio of the polymerizable ultraviolet absorber (b-1) to 100 parts by mass of the polymerizable compound (A) is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more. . The upper limit is preferably 50 parts by mass, and more preferably 30 parts by mass.

By using this polymerizable ultraviolet absorber (b-1), even if a relatively large amount of the ultraviolet absorber (B) is blended in the insulating layer forming composition (i), the ultraviolet absorber (B) The effect of not significantly reducing the bleeding or scratch resistance on the surface is exhibited.

As the polymerizable ultraviolet absorber (b-1), one or more selected from the following polymerizable benzophenone compounds and polymerizable benzotriazole compounds can be used.

Although an ultraviolet absorber other than the polymerizable ultraviolet absorber (b-1) can be used in combination as the ultraviolet absorber (B), it is not preferable to use a large amount.
Examples of ultraviolet absorbers other than the polymerizable ultraviolet absorber (b-1) include non-polymerizable ultraviolet absorbers (hereinafter referred to as “ultraviolet absorber (b-2)”).

The ratio of the UV absorber other than the polymerizable UV absorber (b-1) in the UV absorber (B) is not particularly limited, but is preferably 0 to 80% by mass, particularly 0 to 0% in the total UV absorber (B). 50 mass% is preferable. The content of the ultraviolet absorber other than the polymerizable ultraviolet absorber (b-1) in the insulating layer forming composition (i) is preferably 20 parts by mass or less with respect to 100 parts by mass of the polymerizable compound (A). 10 parts by mass or less is more preferable.

In the insulating layer forming composition (i), the total content of the ultraviolet absorber (B) is preferably 0.1 to 50 parts by mass, more preferably 1 to 100 parts by mass of the polymerizable compound (A). To 30 parts by mass. Although it varies depending on the thickness of the resulting cured body, that is, the insulating layer, if it is 0.1 parts by mass or more, the weather resistance of the insulating layer itself is good, and if it is 50 parts by mass or less, the entire amount is polymerized. Even if it consists only of the photosensitive ultraviolet absorber (b-1), the curability of the coating film is good and the physical properties are excellent.

The polymerizable benzophenone compound is a compound having at least one organic group having a (meth) acryloyl group (hereinafter referred to as “(meth) acryloyl-containing group”) and at least one benzophenone skeleton. The polymerizable benzophenone compound preferably has one or more hydroxyl groups on at least one of the two benzene rings of the benzophenone skeleton in addition to the (meth) acryloyl-containing group. This hydroxyl group may exist in the benzene ring to which the (meth) acryloyl-containing group is bonded, or may exist in another benzene ring. This hydroxyl group is preferably present at the 2-position of the benzophenone skeleton.

In the polymerizable benzophenone compound, there is usually one (meth) acryloyl-containing group. However, two or more (meth) acryloyl-containing groups may be present, in which case they may be present only in one of the two benzene rings or may be present in both benzene rings. The hydroxyl group is preferably present in the benzene ring in which the (meth) acryloyl-containing group is present. In addition to the (meth) acryloyl-containing group and the hydroxyl group, one or more other substituents may be present on the two benzene rings. Examples of the substituent include hydrocarbon groups such as alkyl groups, alkoxy groups, halogens. Atoms are preferred. The number of carbon atoms of the hydrocarbon group or alkoxy group is preferably 6 or less.

The (meth) acryloyl-containing group is preferably a (meth) acryloyloxy group or an organic group represented by the following formula (1).

^{^{^{-X 1 -R 1 -X 2 -CO-}}} CR = CH 2 ... (1)
In the formula (1), R represents a hydrogen atom or a methyl group, X ¹ represents an oxygen atom, —OCONH—, —OCH ₂ CH (OH) — or a single bond, and R ¹ represents a divalent hydrocarbon group. X ² represents an oxygen atom, —O — (— COCH ₂ CH ₂ O—) _k — (k is an integer of 1 or more), —NH—, or —CH (OH) CH ₂ O—. Preferably, R is a hydrogen atom, X ¹ is an oxygen atom or a single bond, R ¹ is an alkylene group having 1 to 6 carbon atoms, and X ² is an oxygen atom.

Preferred (meth) acryloyl-containing groups are (meth) acryloyloxy groups, (meth) acryloyloxyalkyl groups, ((meth) acryloyloxy) alkoxy groups, and carbons other than the latter two (meth) acryloyloxy groups. The number is preferably 2-4.

Preferred polymerizable benzophenone compounds are 2-hydroxybenzophenones having a (meth) acryloyl-containing group in the hydroxyphenyl group. This compound is represented by the following formula (2). In the following formula (2), A represents the (meth) acryloyl-containing group as described above, and R ² and R ³ represent substituents other than the (meth) acryloyl-containing group as described above.

Examples of specific polymerizable benzophenone compounds include the following compounds. 2-hydroxy-4- (meth) acryloyloxybenzophenone, 2-hydroxy-4- (2- (meth) acryloyloxyethoxy) benzophenone, 2-hydroxy-4- (2-acryloyloxypropoxy) benzophenone, 2,2 ′ -Dihydroxy-4- (meth) acryloyloxybenzophenone, 2,2'-dihydroxy-4- (2- (meth) acryloyloxyethoxy) benzophenone.

The polymerizable benzotriazole-based compound is preferably a compound having one or more (meth) acryloyl-containing groups and one or more benzotriazole rings. Usually, a benzotriazole compound having ultraviolet absorbing ability has a skeleton in which one benzene ring is bonded to the 2-position of the benzotriazole ring, that is, 2-phenylbenzotriazole as a skeleton, and further a hydroxyl group at the 2-position of the phenyl group. Have

Among the polymerizable benzotriazole compounds, those having such 2-phenylbenzotriazole as a skeleton and a hydroxyl group at the 2-position of the phenyl group are preferable. The (meth) acryloyl-containing group may be present in the 4 to 8 position of the benzotriazole ring, and is preferably present in the 3 to 6 position of the phenyl group. Two or more (meth) acryloyl-containing groups may be present, and preferably one is present.

One or more substituents may be present at positions where the (meth) acryloyl-containing group at positions 4 to 8 of the benzotriazole ring and positions 3 to 6 of the phenyl group is not present. Of these, a hydrocarbon group, a hydroxyl group, an alkoxy group, a halogen atom and the like are preferable. The number of carbon atoms of the hydrocarbon group or alkoxy group is preferably 6 or less.

The (meth) acryloyl-containing group is preferably a (meth) acryloyloxy group or an organic group represented by the above formula (1). More preferable (meth) acryloyl-containing groups are the (meth) acryloyloxy group, (meth) acryloyloxyalkyl group, ((meth) acryloyloxy) alkoxy group, and the latter two (meth) acryloyl groups as described above. The number of carbon atoms other than the oxy group is preferably 2-4.

Preferred polymerizable benzotriazole compounds are 2- (2-hydroxyphenyl) benzotriazoles having a (meth) acryloyl-containing group in the 2-hydroxyphenyl group. This compound is represented by the following formula (3). In the following formula (3), A represents the (meth) acryloyl-containing group as described above, and R ⁴ and R ⁵ represent substituents other than the (meth) acryloyl-containing group as described above.

Specific examples of polymerizable benzotriazole compounds include the following compounds. 2- {2-hydroxy-5-((meth) acryloyloxy) phenyl} benzotriazole, 2- {2-hydroxy-3-methyl-5-((meth) acryloyloxy) phenyl} benzotriazole, 2- {2 -Hydroxy-3-t-butyl-5-((meth) acryloyloxy) phenyl} benzotriazole, 2- {2-hydroxy-5- (2- (meth) acryloyloxyethyl) phenyl} benzotriazole, 2- { 2-hydroxy-5- (3- (meth) acryloyloxypropyl) phenyl} benzotriazole, 2- {2-hydroxy-3-tert-butyl-5- (2- (meth) acryloyloxyethyl) phenyl} benzotriazole .

2- {2-hydroxy-3-t-butyl-5- (3- (meth) acryloyloxypropyl) phenyl} benzotriazole, 2- {2-hydroxy-3-methyl-5- (2- (meth) acryloyl) Oxyethyl) phenyl} benzotriazole, 2- {2-hydroxy-3-methyl-5- (3- (meth) acryloyloxypropyl) phenyl} benzotriazole, 2- {2-hydroxy-5- (2- (meta ) Acryloyloxyethyl) phenyl} -5-chlorobenzotriazole, 2- {2-hydroxy-5- (2- (meth) acryloyloxyethyl) phenyl} -5-methylbenzotriazole, 2- {2-hydroxy-5 -(2- (2- (meth) acryloyloxyethoxycarbonyl) ethyl) phenyl} benzotriazo Le 2- {2-hydroxy-5- (2- (meth) acryloyloxy ethoxy) phenyl} benzotriazole, 2- {2-hydroxy-5- (2- (meth) acryloyloxy) phenyl} benzotriazole.

As the ultraviolet absorber (b-2), a known or known ultraviolet absorber that is commercially available can be used. Examples of such UV absorbers include benzotriazole UV absorbers, benzophenone UV absorbers, salicylic acid UV absorbers, and phenyltriazine UV absorbers. Specific examples include the following compounds.

Octyl 3- {3- (2H-benzotriazol-2-yl) -5-t-butyl-4-hydroxyphenyl} propionate, 2- (3,5-di-t-pentyl-2-hydroxyphenyl) benzotriazole, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-3-tert-butyl-5) -Methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) -5-chlorobenzotriazole, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy Benzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, pt-butylphenyl salicylate Door.

As the photopolymerization initiator (C), aryl ketone photopolymerization initiators (for example, acetophenones, benzophenones, alkylaminobenzophenones, benzyls, benzoins, benzoin ethers, benzyldimethylketals, benzoylbenzoates, α-acyloxime esters), sulfur-containing photopolymerization initiators (eg, sulfides, thioxanthones, etc.), acylphosphine oxides (eg, acyldiarylphosphine oxides), and other photopolymerization initiators. A photoinitiator may be used independently and may use 2 or more types together. The photopolymerization initiator can be used in combination with a photosensitizer such as amines. Specific photopolymerization initiators include the following compounds.

4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 4-t-butyl-trichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4- Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-methylpropan-1-one, 1- {4- (2-hydroxyethoxy) phenyl} -2 -Hydroxy-2-methyl-propan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- {4- (methylthio) phenyl} -2-morpholinopropan-1-one.

Benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 3, 3 '-Dimethyl-4-methoxybenzophenone, 3,3', 4,4'-tetrakis (t-butylperoxycarbonyl) benzophenone, 9,10-phenanthrenequinone, camphorquinone, dibenzosuberone, 2-ethylanthraquinone, 4 ', 4 "-diethylisophthalophenone, α-acyloxime ester, methylphenylglyoxylate.

4-benzoyl-4′-methyldiphenyl sulfide, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4 -Diisopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

The content of the photopolymerization initiator (C) in the insulating layer forming composition (i) is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable compound (A).
The composition for forming an insulating layer (i) may contain an appropriate amount of a polymerization inhibitor such as hydroquinone monomethyl ether for the purpose of adjusting the degree of polymerization of the polymerizable component by ultraviolet irradiation.

In the insulating layer forming composition (i), if necessary, a high molecular weight compound such as an acrylic (co) polymer, an antioxidant, a light stabilizer, a stabilizer such as a thermal polymerization inhibitor, a leveling agent, Defoamers, thickeners, anti-settling agents, pigment dispersants, antifogging agents and other surfactants, near infrared absorbers, and the like may be appropriately blended and used.

By, for example, blending an acrylic (co) polymer such as polymethyl methacrylate with the composition for forming an insulating layer (i), the adhesion of the insulating layer made of the resulting cured product can be increased, Leveling can be improved. The content of the high molecular weight compound such as an acrylic (co) polymer in the insulating layer forming composition (i) is preferably 20 parts by mass or less with respect to 100 parts by mass of the polymerizable compound (A).

In the insulating layer forming composition (i), colloidal silica (D) may be further blended for the purpose of further improving the scratch resistance of the insulating layer made of the cured product. Colloidal silica (D) is an ultrafine particle of silicic acid colloid dispersed in a dispersion medium composed of water, methanol or the like, and the average particle size of colloidal silica (D) is usually about 1 to 1000 nm, preferably Has an average particle size of 1 to 200 nm, particularly preferably an average particle size of 1 to 50 nm.

The colloidal silica (D) has a particle surface modified with a hydrolyzate of a hydrolyzable silane compound in order to improve dispersion stability, that is, a part or all of the silanol groups on the surface of the colloidal silica particle. In addition, it is also possible to use a silane compound hydrolyzate that is bonded and retained by a condensation reaction and whose surface characteristics are modified.

When the colloidal silica (D) is blended in the insulating layer forming composition (i), the blending amount (solid content) is 500 parts by mass or less, particularly 300 parts by mass or less, based on 100 parts by mass of the polymerizable compound (A). preferable. When mix | blending colloidal silica (D), the compounded effect is exhibited by mix | blending 0.1 mass part or more with respect to 100 mass parts of polymeric compounds (A).

In addition to the ultraviolet absorber (B), a light stabilizer is preferably added to the insulating layer forming composition (i) in order to improve the stability to light. The light stabilizer is preferably a hindered amine light stabilizer, particularly a hindered amine light stabilizer having a 2,2,6,6-tetramethylpiperidine residue. Specifically, for example, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate,

methyl

1,2, 2,6,6-pentamethyl-4-piperidyl) sebacate, 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6 6-pentamethyl-4-piperidyl) and the like.

When the light stabilizer is blended in the insulating layer forming composition (i), the blending amount is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less with respect to 100 parts by mass of the polymerizable compound (A).

Further, in order to impart water repellency to the insulating layer 4, the fluorine-containing polymerizable compound (e-1) represented by the following formula (4) is added to the water repellent polymerizable compound (i) in the insulating layer forming composition (i). You may mix | blend as E).

_{^{CH 2 = C (R 6)}} COOX 3 R f ... (4)
(In the formula (4), R ⁶ represents a hydrogen atom, a methyl group or a trifluoromethyl group, X ³ represents a divalent organic group having 1 to 6 carbon atoms, and R ^f represents a paroxy group having 4 to 6 carbon atoms. Represents a fluoroalkyl group.)

Examples of the fluorine-containing polymerizable compound (e-1) represented by the above formula (4) include the following.

_{^{CH 2 = C (R 6)}} COOR 7 R f
_{^{^{CH 2 = C (R 6)}}} COOR 7 NR 8 SO 2 R f
CH ₂ = C (R ⁶ ) COOR ⁷ NR ⁸ COR ^f
_{^{_{CH 2 = C (R 6)}}} COOCH 2 CH (OH) R 9 R f
Here, R ⁷ represents an alkylene group having 1 to 6 carbon atoms, R ⁸ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁹ represents a single bond or an alkylene group having 1 to 4 carbon atoms.

In the above formula (4), X ³ is preferably an alkylene group having 2 to 4 carbon atoms from the viewpoint of availability.

Specific examples of the fluorine-containing polymerizable compound (e-1) represented by the above formula (4) include perfluorohexylethyl (meth) acrylate and perfluorobutylethyl (meth) acrylate.
The polymerizable compound represented by the above formula (4) may be used alone or in combination of two or more.

When R ^f is a perfluoroalkyl group having 4 to 6 carbon atoms, the fluorine-containing polymerizable compound (e-1) has good compatibility with other components such as the polymerizable compound (A), When the coating film of the insulating layer forming composition (i) is cured, the polymers do not aggregate. Therefore, the appearance of the insulating layer 4 as a cured body is good without being clouded, and the adhesion between the insulating layer 4 and its lower layer (for example, the high resistance layer 3) is increased. When R ^f is a perfluoroalkyl group having 4 or more carbon atoms, the water repellency of the insulating layer 4 is good. On the other hand, when R ^f is a perfluoroalkyl group having 6 or less carbon atoms, when the coating film is cured, the insulating layer 4 which is a cured body does not become cloudy, and the insulating layer 4 and its lower layer (for example, the high resistance layer 3) ).

Further, the insulating layer forming composition (i) may be blended with an organic solvent for the purpose of improving the coating property of the coating film and the adhesion to the lower layer such as the high resistance layer 3. The organic solvent is not particularly limited as long as there is no problem in the solubility of the polymerizable compound (A), the ultraviolet absorber (B), the photopolymerization initiator (C), and other additives, and satisfies the above performance. Anything is acceptable. Moreover, you may use individually and may use 2 or more types of organic solvents together. The content of the organic solvent in the insulating layer forming composition (i) is suitably 100 times or less, particularly 50 times or less, of the polymerizable compound (A).

Examples of the organic solvent include organic solvents such as lower alcohols, ketones, ethers, cellosolves and the like. In addition, esters such as n-butyl acetate and diethylene glycol monoacetate, halogenated hydrocarbons, hydrocarbons and the like can be used.

The insulating layer 4 made of a cured product of the insulating layer forming composition (i) is a surface on the high resistance layer 3 side of the laminate having the high resistance layer 3 on the transparent substrate 2, for example, for the tactile sensor shown in FIG. In the case of the front plate 1, the insulating layer forming composition (i) containing each of the above components is applied to the upper surface S 3 of the high resistance layer 3 by spin coating, dip coating, flow coating, spray coating, bar coating. In the case of a composition containing an organic solvent, it is formed by drying and then irradiating it with ultraviolet rays and curing it by a method such as a coating method, a gravure coating method, a roll coating method, a blade coating method or an air knife coating method. be able to.

For example, when the insulating layer forming composition (i) is applied by applying a spin coating method, an insulating layer is formed on the surface of the laminate having the high resistance layer 3 on the transparent substrate 2 on the high resistance layer 3 side. After dropping the composition (i), the stage for mounting and fixing the laminate is rotated at a predetermined number of rotations, so that the composition for forming an insulating layer ( The uniform coating film of i) can be formed. As for the film thickness of the coating film, the dropping amount of the composition for forming an insulating layer (i) and the rotation speed of the stage are appropriately selected so that the insulating layer obtained after curing has a film thickness within the range of the present invention. It will be adjusted.

Specifically, for example, when the amount of the insulating layer forming composition (i) dropped onto the coated surface of the laminate having the high resistance layer 3 on the transparent substrate 2 is about 1 cm ³ , the laminate It is preferable to rotate the stage on which is mounted at an initial rotational speed of about 200 to 2000 rpm for about 10 to 15 seconds, and then at a maximum rotational speed of about 2000 to 3000 rpm for about 0.1 to 1 second.
In the case where the insulating layer forming composition (i) contains an organic solvent, the organic solvent can be removed by holding the laminated body after the coating film is formed, for example, at a temperature range of 100 to 150 ° C. for about 10 minutes. preferable.

Examples of ultraviolet sources used for ultraviolet irradiation include xenon lamps, low-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, metal halide lamps, carbon arc lamps and tungsten lamps.

The irradiation time and irradiation intensity of ultraviolet irradiation are appropriately changed according to the conditions such as the type of the polymerizable compound (A), the type of the ultraviolet absorber (B), the type of the photopolymerization initiator (C), the film thickness, and the ultraviolet ray source. Can be done. Usually, the object is achieved by irradiation for about 1 to 60 seconds. Further, for the purpose of completing the curing reaction, heat treatment can be performed after the irradiation with ultraviolet rays.

The irradiation time and irradiation intensity of ultraviolet irradiation are appropriately adjusted so that, for example, the energy integrated value of irradiation light is about 500 to 2000 mJ / cm ² and the peak value of irradiation intensity is 100 to 500 mW / cm ^2. Is preferred.

In the case where the insulating layer 4 is formed by applying and curing the insulating layer forming composition (i) as described above on the upper surface S3 of the high-resistance layer 3 made of a layer containing, for example, a metal oxide as a main component. Is a surface treatment (hereinafter referred to as adhesion treatment) for improving the adhesion with the insulating layer 4 on the upper surface S3 of the high resistance layer 3 in order to enhance the adhesion between the high resistance layer 3 and the insulating layer 4. It is preferable to apply the insulating layer forming composition (i) after applying.

For the surface treatment for improving adhesion, for example, the following silane coupling agents can be used.

For example, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxy Silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, and 3- (meta ) Acryloxypropyltrimethoxysilane is mentioned as a silane coupling agent used for surface treatment.

For the adhesion treatment, a composition obtained by mixing the above silane coupling agent with an organic solvent such as lower alcohols, ketones, ethers, cellosolves, etc., is applied to the upper surface S3 of the high resistance layer 3 by spin coating or dipping. It can be performed by applying and drying by a coating method, a flow coating method, a spray coating method, a bar coating method, a gravure coating method, a roll coating method, a blade coating method, an air knife coating method or the like.

For example, in the case of performing the adhesion treatment of the upper surface S3 of the high resistance layer 3 by applying the spin coating method, a laminate having the high resistance layer 3 is prepared on the transparent substrate 2, and the upper surface S3 of the high resistance layer 3 is prepared. After dropping the composition containing the silane coupling agent described above, the stage on which the laminate is placed and fixed is rotated at a predetermined number of revolutions, so that the upper surface S3 of the high resistance layer 3 of the laminate is provided. A thin film of a composition containing a silane coupling agent can be formed and an adhesion treatment can be performed.

Specifically, for example, when the dropping amount of the composition containing the silane coupling agent to the upper surface S3 of the high resistance layer 3 is about 1 cm ³ , the rotation of the stage on which the stacked body is placed, It is preferable that the initial rotation speed is 500 rpm to 1500 rpm for about 5 to 15 seconds, and then the maximum rotation speed is 1500 rpm to 2500 rpm for 0.1 to 1 second.
When the composition used for the adhesion treatment contains an organic solvent, it is preferable to remove the organic solvent by holding the laminate after the adhesion treatment at 100 to 150 ° C. for about 30 minutes.

[Insulating layer forming composition (ii)]
The insulating layer forming composition (ii) is not particularly limited as long as it can obtain a light-transmitting cured product after heat curing. For example, colloidal silica (f-1) and the following formula (5) Those comprising an aqueous / organic solvent dispersion (F) containing a solid component comprising a partial condensate (f-2) of an organoalkoxysilane represented by the formula (1) can be suitably used. The aqueous / organic solvent dispersion refers to an embodiment in which solid components are dispersed in an aqueous medium and / or an organic solvent.

As the organoalkoxysilane, for example, one represented by the following formula (5) can be used.

(R ¹⁰ ) _a Si (OR ¹¹ ) _4-a (5)
(In the formula (5), R ¹⁰ is a monovalent hydrocarbon group having 1 to 6 carbon atoms, R ¹¹ is a monovalent hydrocarbon group or hydrogen group having 1 to 6 carbon atoms, and a is an integer of 0 to 2) is there.)
R ¹⁰ and R ¹¹ are preferably alkyl groups having 1 to 4 carbon atoms.

The organoalkoxysilane included within the scope of the above formula (5) is preferably methyltrimethoxysilane, methyltrihydroxysilane, or a mixture thereof, which can form a partial condensate (f-2). Is. Other than the above, examples of the organotrialkoxysilane included in the range of the formula (5) include tetraethoxysilane, ethyltriethoxysilane, diethyldiethoxysilane, tetramethoxysilane, methyltrimethoxysilane, and dimethyldimethoxy. Examples include silane.

As the aqueous / organic solvent dispersion (F), for example, those shown in US Pat. No. 3,986,997 of Clark can be used.

As the aqueous / organic solvent dispersion (F), in addition to those described above, for example, U.S. Pat. Nos. 3,986,997, 4,624,870, 4,680,232, and Those shown in US Pat. No. 4,914,143 can be used.

Specifically, the aqueous / organic solvent dispersion (F) can be produced by adding a trialkoxysilane such as methyltrimethoxysilane to the aqueous / organic solvent dispersion of colloidal silica. Examples of such an aqueous / organic solvent dispersion of colloidal silica include “Ludox HS” (manufactured by DuPont) and “Nalco” 1034A (manufactured by Nalco Chemical Co.). “OSCAL” (trade name, manufactured by Catalyst Kasei Kogyo Co., Ltd.), “organosilica sol” (trade name, manufactured by Nissan Chemical Industries, Ltd.) and the like.

As the aqueous / organic solvent dispersion of colloidal silica (f-1), for example, those shown in Ubersax US Pat. No. 4,177,315 can be used.

The organoalkoxysilane partial condensate (f-2) is preferably composed of a mixture of various organoalkoxysilane partial condensates.

The aqueous / organic solvent dispersion (F) itself (that is, the combination of colloidal silica (f-1) and organoalkoxysilane partial condensate (f-2)) usually has a solid content of about 10% to 50% by mass. %, Preferably about 15% to 25% by weight of the solid content.

The composition for forming an insulating layer (ii) is generally used to improve the adhesion to the coated surface, for example, the surface S3 of the high resistance layer 3 on the side opposite to the transparent substrate 2, so that the organoalkoxysilane, colloidal silica ( It is preferable to mix the adhesion promoter (G) with the aqueous / organic solvent dispersion (F) containing f-1) and a sufficient amount of alcohol.

As the adhesion promoter (G), for example, (meth) acrylate esters described in US Pat. No. 5,411,807 can be used. Specifically, as the (meth) acrylate ester, for example, a commercially available Tone monomer from Union Carbide Coating Resins may be used as the adhesion promoter (G). .

As the (meth) acrylate ester, for example, caprolactone (meth) acrylate can be suitably used as the adhesion promoter (G).

(Meth) acrylate ester is usually used in an amount of about 1 to 20 parts by mass based on 100 parts by mass of resin solids. The (meth) acrylate ester is preferably used in an amount of about 3 to 8 parts by mass based on 100 parts by mass of the resin solid content.

As the adhesion promoter (G), polyester polyol can be used as other than the above. As the polyester polyol, for example, a caprolactone-based polyester polyol described in US Pat. No. 5,349,002 can be used.

Many of the caprolactone-based polyester polyols are difunctional or trifunctional, and for example, those commercially available as Tone polyols from Union Carbide can be used. Specifically, for example, “Tone 0200 diol” (trade name, manufactured by Union Carbide), “Tone 0301 Triol” (trade name, manufactured by Union Carbide), “Tone 0310 Triol” (trade name, Union Carbide) Carbide) and the like can be used.
In addition, what is marketed as Tone polyol, and various things from which said molecular weight, a hydroxy value, melting | fusing point, a viscosity etc. differ from said thing can also be used as an adhesion promoter (G).

As the polyester polyol other than the caprolactone-based polyester polyol, urethane-modified polyester polyol or silicone-modified polyester polyol can be used.

The polyester polyol can be usually used in an amount of about 1 to 10 parts by mass based on 100 parts by mass of the resin solid content.

As the adhesion promoter (G), acrylic urethane can be used as other than the above. As the acrylic urethane, for example, those described in US Pat. No. 5,503,935 can be used. Acrylic urethanes typically have a molecular weight in the range of about 400-1500, generally have semi-solid or viscous properties, and can be added directly to the aqueous / organic solvent dispersion (F).

Specific examples of the acrylic urethane include, for example, “Actylane CB-32” (trade name, manufactured by SNPE® Chimie (France)) and “Ebecryl 8804” (trade name, Radcure Specialties). (Radcure Specialties) ４０sha (Louisville, Kent.), Etc., such as “M-407” (trade name, Echo Resins & Laboratory) etc. it can. “M-407” is an adduct of isophorone diisocyanate and 2-hydroxyethyl methacrylate and has a molecular weight of about 482.

Acrylic urethane can be usually used in an amount of about 1 to 15 parts by mass based on 100 parts by mass of resin solids.

As the adhesion promoter (G), an acrylic copolymer (g-1) having a reactive site or an interactive site and having a number average molecular weight of about 1000 to about 10,000 can be used as a material other than the above. As the acrylic copolymer (g-1) (usually thermosetting), for example, those described in US Pat. No. 5,503,935 can be used, and these are aqueous / organic solvent dispersions. It can be added directly to (F).

A preferred acrylic copolymer (g-1) has a hydroxyl group as a reactive site or interaction site, a hydroxy value in the range of about 30 to 160, an acid value of less than about 4, and about It has a number average molecular weight of 1000 to 10,000.
Examples of the acrylic copolymer (g-1) are those described in Mark et al., “Encyclopedia of Polymer Science and Engineering, Vol. 4 (published by John Wiley & Sons, 1986)”, pages 374-375. These can be synthesized by radical polymerization of various comonomers.

The acrylic copolymer (g-1) is K.K. J. et al. As described in “Organic Polymer Chemistry” (issued by Chapman Hall (London), 1973) by Saunders, the copolymer has a combination of suitable properties by using a plurality of types of monomers. can do.

For example, when a monomer such as acrylonitrile or methyl methacrylate is used, generally, the acrylic copolymer (g-1) is given hardness, and a single amount such as ethyl acrylate or 2-ethylhexyl acrylate. When the body is used, the acrylic copolymer (g-1) is given flexibility. Further, by using a monomer such as dimethylaminoethyl methacrylate or acrylic acid, a reactive site suitable for polymerization is usually provided.

The acrylic copolymer (g-1) as the adhesion promoter (G) may contain an amino group, a carboxyl group, an amide bond, an epoxy group, a hydroxyl group, or an acyloxy group.

Specific examples of the acrylic copolymer (g-1) include, for example, an acrylic polyol “Joncry (trademark)” (trade name, manufactured by BASF), an acryloid acrylic resin (Rohm and Haas ( Rohm and Haas Company) can be used as the adhesion promoter (G).

As described in US Pat. No. 5,503,935, the acrylic copolymer (g-1) is preferably a hydroxyalkyl acrylate copolymer because it has a reactive site or interaction site with a silanol group. . The acrylic copolymer (g-1) can be obtained, for example, by using the method described in the paper “Journal of Coating Technology, Vol. 59, No. 746 (March, 1987)” by Kamath et al. What was manufactured can be used as a suitable thing of an adhesion promoter (G).

The acrylic copolymer (g-1) can usually be used in an amount of about 1 to 15 parts by mass based on 100 parts by mass of the resin solid content.

For the preparation of the aqueous / organic solvent dispersion (F), for example, alcohols having 1 to 4 carbon atoms such as methanol, ethanol, propanol, isopropanol, butanol; organic solvents such as glycols and glycol ethers such as propylene glycol methyl ether, and These mixtures can be used suitably.

When the insulating layer forming composition (ii) comprises the aqueous / organic solvent dispersion (F) as described above, the insulating layer forming composition (ii) is made of colloidal silica (f-1 ) In an amount of 10 to 50% by weight and a solid content of 10 to 70% by weight and a partial condensate of organoalkoxysilane represented by the formula (5) (f-2) 30 to 90% by weight It is preferable to contain 1 to 10 parts by mass of an adhesion promoter (G) made of an acrylic polyol with respect to 100 parts of the solvent dispersion (F).

As the ultraviolet absorber (J) to be blended in the insulating layer forming composition (ii), those which react with the organoalkoxysilane and hardly volatilize during the heat curing step are suitable. Examples of the ultraviolet absorber (J) include 2-hydroxy-4- (3- (trimethoxysilyl) propoxy) benzophenone, (2-hydroxy-4- (3- (triethoxysilyl) propoxy) benzophenone, and their The ultraviolet absorber (J) can be blended at a concentration of 0.1 to 20% by mass with respect to the insulating layer forming composition (ii).

The insulating layer forming composition (ii) contains free radical initiators, sterically hindered amine light stabilizers, antioxidants, dyes, flow improvers and other additives such as leveling agents or surface lubricants. It can also be blended.

Insulating layer forming composition (ii) has a catalyst such as tetrabutylammonium carboxylate such as tetra-n-butylammonium acetate (TBAA) or tetra-n-butylammonium formate to shorten the curing time. A catalyst or an acid such as acetic acid can also be blended.

The insulating layer 4 made of a cured product of the insulating layer forming composition (ii) is a surface on the high resistance layer 3 side of the laminate having the high resistance layer 3 on the transparent substrate 2, for example, for the tactile sensor shown in FIG. In the case of the front plate 1, the insulating layer forming composition (ii) containing each of the above components is applied to the upper surface S 3 of the high resistance layer 3 by spin coating, dip coating, flow coating, spray coating, bar coating. After applying by a known arbitrary coating method such as a coating method, a gravure coating method, a roll coating method, a blade coating method, an air knife coating method, etc., and then heating at 100 to 150 ° C. for about 30 to 90 minutes, It can be formed by heating and curing using microwave energy.

For example, when the insulating layer forming composition (ii) is applied by applying a spin coating method, an insulating layer is formed on the surface of the laminate having the high resistance layer 3 on the transparent substrate 2 on the high resistance layer 3 side. After the composition (ii) is dropped, the stage for mounting and fixing the laminate is rotated at a predetermined number of rotations, so that the composition for forming an insulating layer ( The uniform coating film of ii) can be formed. As for the film thickness of the coating film, the dropping amount of the composition for forming an insulating layer (ii) and the rotational speed of the stage are appropriately selected so that the insulating layer obtained after curing has a film thickness within the range of the present invention. It will be adjusted.

Specifically, the rotation of the stage for mounting and fixing the laminate is, for example, the amount of the insulating layer forming composition (ii) dropped onto the application surface of the laminate having the high resistance layer 3 on the transparent substrate 2. Is about 1 cm ³ , it is preferable that the initial rotation speed is 100 to 300 rpm for about 10 to 15 seconds, and then the maximum rotation speed is about 1500 to 2500 rpm and the rotation time is 0.1 to 1 second.

By forming the insulating layer 4 as a layer obtained by curing the insulating layer forming composition (ii) as described above, the formation speed of the insulating layer 4 is increased as compared with the case of using a technique such as sputtering. Thus, the manufacturing efficiency of the touch sensor front plate 1 can be increased.

The thickness of the insulating layer 4 is 0.5 μm or more and 15 μm or less, preferably 0.5 μm or more and 10 μm or less, more preferably 1 μm or more and 10 μm or less, and further preferably 1 μm or more and 8 μm or less.
When the thickness of the insulating layer 4 is less than 0.5 μm, the surface shape of the interface S3 of the high resistance layer 3 with the insulating layer 4 is changed to the surface S2 of the insulating layer 4 opposite to the high resistance layer 3 side. The surface of the insulating layer 4 on the side opposite to the high resistance layer 3 side, for example, because the convex portion of the interface S3 between the high resistance layer 3 and the insulating layer 4 partially protrudes from the insulating layer 4 or the like. The shape is affected, and the surface roughness Ra is excessively high on the surface of the front plate 1 for the tactile sensor, and the visibility may be deteriorated due to white clouding or the like.

By setting the thickness of the insulating layer 4 to 0.5 μm or more, white clouding on the surface of the touch sensor front plate 1 can be suppressed, and excellent visibility can be obtained, and sufficient wear resistance and weather resistance can be obtained. Sex can be obtained. On the other hand, by setting the thickness of the insulating layer 4 to 15 μm or less, the curing sufficiently proceeds even in the deep part of the insulating layer 4 and excellent light transmission can be obtained. Bending strength can be obtained.

In the touch sensor front plate 1 shown in FIG. 3, when the insulating layer 4 does not contain a component imparting water repellency such as the fluorine-containing polymerizable compound (e-1), this insulating layer 4 is the surface opposite to the high resistance layer 3 side, that is, the water in contact with the surface S2 of the tactile sensor front plate 1 is easily diffused and adhered to the surface S2, and the high resistance layer 3 in which charges are accumulated Since the electrostatic attractive force (Coulomb force) acting between the sensory receptor X such as a fingertip adjacent to the surface layer of the insulating layer 4 is shielded, there is a possibility that the function as a tactile sensor cannot be sufficiently obtained. Therefore, a water repellent layer 6 can be further formed on the surface S2 of the insulating layer 4 that does not contain a sufficient amount of a component imparting water repellency, as shown in FIG. In this case, the surface of the touch sensor front plate 1 is a surface S5 of the water repellent layer 6 opposite to the insulating layer 4 side.

Specifically, for example, the insulating layer 4 is a layer formed of a cured product of the insulating layer forming composition (i) that does not contain a component imparting water repellency such as the above-described fluorine-containing polymerizable compound (e-1). In this case, it is preferable to form the water repellent layer 6 on the upper surface S2 of the insulating layer 4.

By adopting such a configuration, moisture does not contact the surface S2 of the insulating layer 4, and therefore, the static force acting between the high-resistance layer 3 and the sensory receptor X that is likely to occur when the water-repellent layer 6 is not provided. The shielding of the electric attractive force (Coulomb force) can be suppressed and the function as a tactile sensor can be sufficiently obtained in the front plate 1 for tactile sensor.

The water repellent layer 6 can be formed of a layer made of a cured product of a water repellent layer-forming composition containing a fluorine-containing compound or a silicon-containing compound (hereinafter referred to as a water repellent (H)).

Examples of the fluorine-containing compound or silicon-containing compound constituting the water repellent (H) include silane coupling agents. As silane coupling agents, fluorine-containing silane coupling agents, silane coupling agents having amino groups, silane coupling agents having (meth) acryloyl groups, silane coupling agents having thiol groups, silane cups having isocyanate groups Examples thereof include a ring agent and a silane coupling agent having an oxiranyl group. Commercial products such as FS-10 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be employed.

As the silane coupling agent, a fluorine-containing silane coupling agent is preferable from the viewpoint of water repellency and the like, and a silane coupling agent having a fluoroalkyl group is particularly preferable. Examples of the fluoroalkyl group include a perfluoroalkyl group; a fluoroalkyl group containing a perfluoro (polyoxyalkylene) chain, and the like.

Commercially available silane coupling agents having a fluoroalkyl group include AQUAPHOBE (registered trademark) CF manufactured by Gelest, Novec (registered trademark) EGC-1720 manufactured by MIM, and OPTOOL (registered trademark) DSX manufactured by Daikin. (Silane coupling agent having a perfluoro (polyoxyalkylene) chain) and the like.
Examples of the silane coupling agent having an amino group include aminopropyltriethoxysilane, aminopropylmethyldiethoxysilane, aminoethyl-aminopropyltrimethoxysilane, aminoethyl-aminopropylmethyldimethoxysilane, and the like.

The water repellent layer 6 is an insulating material for a laminate in which the water repellent layer-containing composition containing the above-described water repellent is laminated in the order of, for example, the transparent substrate 2, the high resistance layer 3, and the insulating layer 4 shown in FIG. A method of applying heat treatment after coating on the surface S2 opposite to the high resistance layer 3 side of the layer 4, or a heat treatment after vapor-depositing a water repellent on the surface S2 of the insulating layer 4 in the laminate. It can form by the method to do.

When the water repellent layer 6 is formed by application of the water repellent layer forming composition, examples of the application method include spin coating, dip coating, casting, slit coating, and spray coating. The temperature for the heat treatment is preferably 20 to 150 ° C., and particularly preferably 70 to 140 ° C. from the viewpoint of productivity. In order to increase the reactivity of the water repellent, the humidity may be controlled during the heat treatment.

In the case of forming the water repellent layer 6 by vapor deposition of the water repellent layer forming composition, for example, after removing the solvent from the water repellent layer forming composition described above, it is heated to 250 to 300 ° C. in a vacuum state, In an atmosphere in which the water repellent (H) is in a gas phase state, for example, a laminated body in which the transparent substrate 2, the high resistance layer 3, and the insulating layer 4 shown in FIG. Then, gas molecules of the water repellent (H) are attached to the surface S2 of the insulating layer 4 opposite to the high resistance layer 3 side to form a uniform thin film of the water repellent (H). be able to.

The front plate 1 for a tactile sensor is not limited to the configuration shown in FIG. 3 or FIG. 6, but has a configuration in which a barrier layer 7 is interposed between the transparent substrate 2 and the high resistance layer 3 as shown in FIG. It is also preferable to do.

By interposing the barrier layer 7 between the transparent substrate 2 and the high resistance layer 3, it is possible to suppress the components contained in the transparent substrate 2 from diffusing into the high resistance layer 3, and the surface resistance value of the high resistance layer 3. Variations in characteristics such as can be suppressed. Moreover, the influence which the surface shape of the transparent base | substrates 2, such as a glass plate, has on the front plate 1 for tactile sensors can be suppressed, and shape stabilization as a whole can be achieved.
The front plate for the tactile sensor having the barrier layer 7 is not necessarily limited to the one having the configuration shown in FIG. 7. For example, the barrier layer 7 is interposed between the transparent substrate 2 and the high resistance layer 3. A structure in which the water repellent layer 6 is laminated on the upper surface of the insulating layer 4 may be used.

Examples of the barrier layer 7 include a layer mainly composed of silicon oxide and a layer mainly composed of a layer mainly composed of silicon oxide and indium oxide. Among these, a layer containing a silicon oxide as a main component is preferable because good light transmittance is easily secured. In addition, among the layers containing silicon oxide as a main component, a layer containing nitrogen, for example, a layer containing silicon oxynitride (SiON) can obtain excellent light transmittance and can be used as the front plate 1 for a tactile sensor. This is preferable because an effect of reducing the luminous reflectance can be obtained.

Similar to the formation of the high-resistance layer 3 described above, the barrier layer 7 is formed on the transparent substrate 2 by sputtering such as DC (direct current) sputtering such as DC (direct current) magnetron sputtering, AC (alternating current) sputtering, or RF (high frequency) sputtering. It can be formed on the surface S1 having the surface roughness Ra.

When the barrier layer 7 is a layer mainly composed of silicon oxide, a target mainly composed of silicon is used as a target used for forming the barrier layer 7. As a target having silicon as a main component, a target composed solely of silicon, or a dopant containing silicon as a main component and a known dopant such as boron or phosphorus other than silicon, as long as the characteristics of the present invention are not impaired. Things.

The formation of the barrier layer 7 by sputtering can be performed by appropriately adjusting conditions such as the pressure of the sputtering gas and the film forming speed in the same manner as the sputtering in the high resistance layer 3 described above.

In the case where the barrier layer 7 is formed of a silicon oxide as a main component and a layer containing nitrogen, for example, a layer containing silicon oxynitride (SiON), for example, oxygen gas and inert gas are used as sputtering gases. Further, nitrogen gas or a mixed gas in which a gas containing nitrogen atoms such as N ₂ O, NO, NO ₂ , NH ₃ or the like is mixed can be used.

The formation of the barrier layer 7 made of an inorganic oxide such as silicon oxide is not limited to the sputtering method as described above. For example, sputtering such as a vacuum vapor deposition method, an ion beam assisted vapor deposition method, and an ion plate method is used. A physical vapor deposition method other than the method, a chemical vapor deposition method such as a plasma CVD method, or the like can be used.

The thickness of the barrier layer 7 is preferably 100 nm or less, more preferably 50 nm or less, and further preferably 30 nm or less. If the thickness of the barrier layer 7 exceeds 100 nm, the surface shape on the surface S1 having the surface roughness Ra of the transparent substrate 2 is not sufficiently reflected in the high resistance layer 3, so the high resistance layer 3 and the insulating layer 4 There is a possibility that the effect of diffusing the reflected light generated at the interface S3 may not be sufficiently obtained. By making the thickness of the barrier layer 7 100 nm or less, the appearance of interference fringes is suppressed and the front plate 1 for the tactile sensor has an appropriate bending strength and sufficient light. It can have transparency.

In the front plate 1 for tactile sensor, the refractive index of the barrier layer 7 is preferably 1.4 to 2.2 from the viewpoint of obtaining excellent visible light transmittance and visible light reflectance.

The surface roughness Ra of the surface of the touch sensor front plate 1 is 0.05 μm or less. By making the surface roughness Ra of the surface of the touch sensor front plate 1 0.05 μm or less, a decrease in light transmittance due to white clouding or the like in the touch sensor front plate 1 is suppressed, and the surface has excellent visibility. can do. The surface roughness Ra of the surface of the touch sensor front plate 1 is more preferably 0.01 to 0.03 μm.

The haze value of the touch sensor front plate 1 is preferably 1% or less, more preferably 0.8% or less, and still more preferably 0.5% or less. By setting the haze value to 1% or less, sufficient light transmittance can be obtained in the front plate 1 for a tactile sensor, and the visibility can be improved.

The luminous transmittance of the front plate 1 for touch sensor is 85% or more. Sufficient visibility can be obtained by having a luminous transmittance of 85% or more. The luminous transmittance of the touch sensor front plate 1 is more preferably 88% or more.
In addition, the luminous reflectance on the surface of the touch sensor front plate 1 is preferably 14% or less, and more preferably 10% or less.
In this specification, the luminous transmittance and luminous reflectance refer to luminous transmittance and luminous reflectance by daylight measured according to JIS R3106 (1998).

The static friction coefficient on the surface of the touch sensor front plate 1 is preferably 0.2 or less, and more preferably 0.15 or less.
The coefficient of dynamic friction on the surface of the front plate 1 for touch sensor is preferably 0.2 or less, and more preferably 0.15 or less.

The tactile sensor front plate 1 has an indentation elastic modulus of 2.5 GPa or more, more preferably 3.0 GPa or more, evaluated on the surface using a micro hardness measurement test.
Here, the “micro hardness measurement test” is a test method for calculating the hardness from the penetration depth, whereby the indentation elastic modulus (GPa) corresponding to the indentation hardness can be known. This hardness serves as a guide indicating the “hardness” of the front plate 1 for a tactile sensor, that is, a mechanical strength such as scratch resistance.

The contact angle with water on the surface of the front plate 1 for touch sensor is preferably 80 degrees or more, and more preferably 90 degrees or more. The contact angle with respect to water is measured using a contact angle meter.

Such a tactile sensor front plate 1 is provided on the front surface of the touch panel body 5 as shown in FIG. 5, for example, and is not shown in a voltage and frequency controlled in a pattern capable of reproducing the tactile sensation to be expressed. By energizing the transparent electrode 5a of the touch panel main body 5 from the control unit and accumulating charges induced on the tactile sensor front plate 1 side in the high resistance layer 3, the front plate 1 for tactile sensor is charged. It is configured. When the sensory receptor X such as a finger is brought into contact with the surface of the front plate 1 for a tactile sensor in such a charged state, a tactile sensation such as an uneven feeling is caused by a weak electrostatic force acting between the two via the insulating layer 4. Sensory receptor X senses it.

In addition, instead of providing the transparent electrode 5 a on the touch panel body 5, a transparent electrode may be provided on the touch sensor front plate 1. That is, the transparent electrode may be disposed on the surface S4 on the opposite side of the tactile sensor front plate 1 where the high resistance layer 3 of the transparent substrate 2 is disposed. Such a configuration is preferable because the structure of the entire touch panel can be simplified and the distance between the transparent electrode and the high-resistance layer 3 becomes short, so that the drive voltage can be suppressed low.

Examples of the material constituting the transparent electrode include tin-doped indium oxide (ITO), indium / gallium-doped zinc oxide (IGZO), and gallium-doped zinc oxide (GZO). Of these, ITO is preferable because of its good permeability, resistance stability and durability. The thickness of the transparent electrode is preferably 50 to 500 nm, and more preferably 100 to 300 nm. A thickness of 50 nm or more is preferable because a sufficient resistance value can be obtained and the stability of the resistance value can be secured. A thickness of 500 nm or less is preferable because sufficient transmittance can be secured.

When a transparent electrode is disposed on the front plate 1 for the tactile sensor, the transparent electrode is formed by first forming a film of a material for forming the transparent electrode by sputtering, vapor deposition or the like, and disposing the high resistance layer 3 of the transparent substrate 2. It is formed on the surface S4 opposite to the surface. Then, the transparent electrode is formed by patterning the film into a desired shape by a photolithography method, a laser patterning method or the like.

According to the touch sensor front plate 1 of the embodiment of the present invention, the surface resistance value of the high resistance layer 3 is 1 to 100 MΩ / □, and the high resistance layer 3 and the touch panel body 5 or the touch sensor are used in use. The desired tactile sensation can be expressed with good reproducibility without causing an electrical action with the transparent electrode of the front plate 1 itself, and the surface of the transparent substrate 2 on the high resistance layer 3 side can be obtained. The surface roughness Ra of S1 is 0.05 to 0.5 μm, and the surface roughness Ra of the surface of the front plate 1 for tactile sensor is 0.05 μm or less, so that a good appearance with suppressed generation of interference fringes is achieved. And having high light transmittance and excellent visibility.

As described above, the embodiments of the front plate for a touch sensor of the present invention have been described with reference to the examples shown in FIGS. 3 to 7, but the front plate for a touch sensor of the present invention is not limited thereto. As long as it does not contradict the spirit of the present invention, the configuration can be changed as necessary.

Hereinafter, specific description will be given with reference to examples. In addition, the following description does not limit this invention, The modification | change in the form along the meaning of this invention is possible. Examples 1 to 5 are examples, and examples 6 to 7 are comparative examples.
<Preparation of insulating layer forming composition b1>
In a 300 mL four-necked flask equipped with a stirrer, 163 g of butyl acetate first grade (manufactured by Junsei Chemical Co., Ltd.) and 41 g of 2-propanol were placed, and a polymerizable benzotriazole ultraviolet absorber (manufactured by Otsuka Chemical Co., Ltd., 2 g of trade name: R-UVA93), 1 g of light stabilizer (manufactured by BASF, trade name: TINUVIN292), 0.65 g of leveling agent (trade name: BYK306, manufactured by Big Chemie), photopolymerization initiator (BASF) Product, product name: IRGACURE907) and 0.1 g of hydroquinone monomethyl ether (manufactured by Junsei Kagaku) as a polymerization inhibitor were added and dissolved to obtain a solution.

Next, 40 g of polyfunctional acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: U15HA), 60 g of polyfunctional acrylate (manufactured by Toagosei Co., Ltd., trade name: M325), and methyl methacrylate are mainly contained in this solution. Add 33 g of high molecular weight (Mitsubishi Rayon Co., Ltd., trade name: LR248, molecular weight of about 150,000, solid content concentration of 30% by mass), stir at room temperature until uniform, dissolve and dissolve, UV curable insulating layer An insulating layer forming composition b1 corresponding to the forming composition (i) was obtained.

[Example 1]
A high resistance layer forming surface of a glass substrate (manufactured by Asahi Glass Co., Ltd., soda lime glass, length 100 mm × width 100 mm × thickness 1 mm) was frosted by HF etching to obtain a glass substrate Q1. The surface roughness Ra of the frosted surface of the glass substrate Q1 after the frosting was 0.093 μm, and the haze value was 15.2%.

The surface roughness Ra of the glass substrate Q1 is determined by measuring the surface shape of the glass substrate Q1 with a laser microscope (manufactured by Keyence Corporation, product name “VK-9700”) at a magnification of 50 times, according to JIS B0601. Calculated. The haze value of the glass substrate Q1 was measured using a haze meter (product name “HZ-1” manufactured by Suga Test Instruments Co., Ltd.).

This glass substrate Q1 was put into a vacuum chamber and evacuated until the pressure in the chamber became 1 × 10 ⁻⁴ Pa. Thereafter, a film forming process was performed on the frosted surface of the glass substrate Q1 by a magnetron sputtering method under the following conditions to form a barrier layer C1 and a high resistance layer A1.

First, conditions of pressure 0.3 Pa, frequency 20 kHz, power density 3.8 W / cm ² , and inversion pulse width 5 μsec using a Si target while introducing a mixed gas obtained by mixing 40 vol% oxygen gas into argon gas. Then, a 20 nm thick barrier layer C1 made of silicon oxide (refractive index: 1.46) was formed on the frosted surface of the glass substrate Q1.

Next, a tin oxide target (manufactured by AGC Ceramics, trade name: GIT target) and a titanium oxide target (manufactured by AGC Ceramics, trade name: TXO) were introduced while introducing a mixed gas in which 2% by volume of oxygen gas was mixed with argon gas. Co-sputtering was performed by a magnetron sputtering method at a pressure of 0.1 Pa.
The GIT target performs pulse sputtering under the conditions of a frequency of 20 kHz, a power density of 3.8 W / cm ² , and an inversion pulse width of 5 μsec. The TXO target is pulsed under the conditions of a frequency of 20 kHz, power density of 4 W / cm ² , and an inversion pulse width of 5 μsec. Sputtering was performed. As a result, a high resistance layer A1 made of tin oxide-titanium oxide and having a thickness of 20 nm was formed on the surface of the glass substrate Q1.

When the atomic composition of the high resistance layer A1 was analyzed by ESCA (Physical® Electronics, device name: Quantera® SXM), the atomic ratio was Sn: Ti = 9: 1. Further, the refractive index of the high resistance layer A1 was calculated from the spectral transmittance and the reflectance, and was 2.1 at a wavelength of 550 nm.

Further, a measuring device (manufactured by Mitsubishi Chemical Analytech Co., Ltd., device name: Hiresta UP (MCP-HT450 type)) is used for the laminate obtained by laminating the glass substrate Q1, the barrier layer C1, and the high resistance layer A1 obtained in the above order. The surface resistance value of the high resistance layer A1 was measured. When the probe was placed at the center of the surface of the high resistance layer A1 of the 10 cm □ laminate and energized at 10V for 10 seconds, the surface resistance value was 50 MΩ / □.

Next, an adhesion treatment was performed on the high resistance layer A1 by the following method.
First, 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM503) was diluted to 0.1% by mass with ethanol, and this diluted solution was dropped about 1 cm ^{3 on} the surface of the high resistance layer A1. After that, the coating was performed with a spin coater while rotating at 1000 rpm for 10 seconds and then at 2000 rpm for 0.5 seconds. Then, it put into the thermostat and hold | maintained for 30 minutes at 120 degreeC. Thus, an adhesion treatment was performed on the high resistance layer A1.

Next, the insulating layer B1 was formed by the following method.
First, about 1 cm ^{3 of the} composition for forming an insulating layer b1 obtained above is dropped on the adhesion-treated surface of the high-resistance layer A1 that has been subjected to the adhesion treatment, and the spin coater is used for 10 seconds at a rotation speed of 200 rpm, and then at 2000 rpm. The coating film was formed by rotating for 0.5 seconds. Then, it put into the thermostat and hold | maintained at 120 degreeC for 10 minute (s), and dried the coating film.

Next, with respect to the laminate on which the dried coating film was formed, using a UV irradiation device with a conveyor (manufactured by USHIO INC., Device name: UVC-02516S1), the integrated value of UV irradiation was 1000 mJ / cm ² , the peak value Is irradiated with UV while adjusting the conveyance speed and the UV intensity so as to be 375 mW / cm ² , the dried coating film is cured, and the insulating layer B1 made of a cured body of the insulating layer forming composition b1 is formed. Formed. The thickness of the insulating layer B1 was 10 μm. Further, the refractive index of the insulating layer B1 was calculated from the spectral transmittance and the reflectance, and was 1.55 at a wavelength of 550 nm.
In this way, a front panel 1 for a tactile sensor in which the barrier layer C1, the high resistance layer A1, and the insulating layer B1 were laminated on the frosted surface of the glass substrate Q1 was obtained.

[Example 2]
First, a high resistance layer A2 was formed on the frosted surface of the glass substrate Q1 that had been frosted in the same manner as in Example 1 under the following conditions.

That is, while introducing a mixed gas obtained by mixing 2% by volume of oxygen gas into argon gas, a titanium oxide target (manufactured by AGC Ceramics, trade name: TXO target) and a niobium oxide target (manufactured by AGC Ceramics, trade name: NBO) Co-sputtering was performed by a magnetron sputtering method at a pressure of 0.1 Pa. The TXO target performs pulse sputtering under the conditions of a frequency of 20 kHz, a power density of 3.8 W / cm ² and an inversion pulse width of 5 μsec, and the NBO target is pulsed under the conditions of a frequency of 20 kHz, power density of 1 W / cm ² and inversion pulse width of 5 μsec. Sputtering was performed. As a result, a high resistance layer A2 made of titanium oxide-niobium oxide and having a thickness of 20 nm was formed on the frosted surface of the glass substrate Q1.

When the atomic composition of the high resistance layer A2 was analyzed by ESCA (manufactured by Physical Electronics, device name: Quantera SXM), the atomic ratio was Ti: Nb = 33: 1. Further, the refractive index of the high resistance layer A2 was calculated from the spectral transmittance and the reflectance, and found to be 2.4 at a wavelength of 550 nm. Furthermore, the surface resistance value of the high resistance layer A2 measured in the same manner as in Example 1 was 30 MΩ / □.

Next, an adhesion treatment was performed on the high resistance layer A2 in the same manner as in Example 1, and then an insulating layer B1 having a thickness of 10 μm was formed in the same manner as in Example 1. Thus, the touch sensor front plate 2 in which the high resistance layer A2 and the insulating layer B1 were laminated on the frosted surface of the glass substrate Q1 was obtained.

[Example 3]
A high resistance layer forming surface of a glass substrate (manufactured by Asahi Glass Co., Ltd., trade name: Dragon Trail, length 100 mm × width 100 mm × thickness 1 mm) was frosted by HF etching to obtain a glass substrate Q2. When the surface roughness Ra and haze value of the frosted surface of the glass substrate Q2 after the frost treatment were measured in the same manner as in Example 1, the surface roughness Ra was 0.103 μm and the haze value was 17.8%. . A tactile sensor front plate 3 was obtained in the same manner as in Example 1 except that this glass substrate Q2 was used in place of the glass substrate Q1.

[Example 4]
A glass substrate (manufactured by Asahi Glass Co., Ltd., soda lime glass, length 100 mm × width 100 mm × thickness 1 mm) is subjected to a frost treatment under conditions where the high resistance layer forming surface is etched deeper than in Example 1 by HF etching. A substrate Q3 was obtained. When the surface roughness Ra and haze value of the frosted surface of the glass substrate Q3 after the frost treatment were measured in the same manner as in Example 1, the surface roughness Ra was 0.133 μm and the haze value was 25.8%. . A tactile sensor front plate 4 was obtained in the same manner as in Example 1 except that this glass substrate Q3 was used in place of the glass substrate Q1.

[Example 5]
First, the barrier layer C1 and the high resistance layer A1 were formed in the same manner as in Example 1 on the frosted surface of the glass substrate Q1 that had been frosted in the same manner as in Example 1. Thereafter, an adhesion treatment was performed on the high resistance layer A1 in the same manner as in Example 1.

Next, about 1 cm ^{3 of the} composition for forming an insulating layer b1 obtained above is dropped on the adhesion-treated surface of the high-resistance layer A1 that has been subjected to the adhesion treatment, and is applied with a spin coater for 10 seconds at a rotation speed of 1000 rpm and then 2000 rpm. Was rotated for 0.5 seconds to form a coating film. Then, it put into the thermostat and hold | maintained at 120 degreeC for 10 minute (s), and dried the coating film.

Next, the laminate on which the dried coating film was formed was irradiated with UV while adjusting the conveyance speed and UV intensity in the same manner as in Example 1 to cure the dried coating film, thereby forming an insulating layer forming composition. An insulating layer B1 made of a cured product of the object b1 was formed. The thickness of the insulating layer B1 was 3 μm.
Thus, the touch sensor front plate 5 in which the barrier layer C1, the high resistance layer A1, and the insulating layer B1 were laminated on the frosted surface of the glass substrate Q1 was obtained.

[Example 6]
Instead of the glass substrate Q1, a glass substrate Q4 made of a glass substrate that is not subjected to frost treatment (manufactured by Asahi Glass Co., Ltd., soda lime glass, vertical 100 mm × horizontal 100 mm × thickness 1 mm) was used in the same manner as in Example 1. Thus, the front plate 6 for tactile sensor was obtained. When the surface roughness Ra and haze value of the high resistance layer forming surface of the glass substrate Q4 used were measured in the same manner as in Example 1, the surface roughness Ra was 0 μm and the haze value was 0%. This means that all are below the measurement limit, that is, the surface roughness Ra is 0.01 μm or less, and the haze value is 0.1% or less.

[Example 7]
First, the barrier layer C1 and the high resistance layer A1 were formed in the same manner as in Example 1 on the frosted surface of the glass substrate Q1 that had been frosted in the same manner as in Example 1. Thereafter, an adhesion treatment was performed on the high resistance layer A1 in the same manner as in Example 1.

Next, about 1 cm ^{3 of the} composition b1 for insulating layer formation obtained above is dropped on the adhesion-treated surface of the high resistance layer A1 that has been subjected to the adhesion treatment, and the spin coater is used for 10 seconds at a rotational speed of 2000 rpm, and then 3000 rpm. Was rotated for 0.5 seconds to form a coating film. Then, it put into the thermostat and hold | maintained at 120 degreeC for 10 minute (s), and dried the coating film.

Next, the laminate on which the dried coating film was formed was irradiated with UV while adjusting the conveyance speed and UV intensity in the same manner as in Example 1 to cure the dried coating film, thereby forming an insulating layer. An insulating layer B1 made of a cured product of the composition b1 was formed. The thickness of the insulating layer B1 was 0.4 μm.
In this way, a front panel 7 for a touch sensor was obtained in which the barrier layer C1, the high resistance layer A1, and the insulating layer B1 were laminated on the frosted surface of the glass substrate Q1.

[Evaluation of front plate for tactile sensor]
For the tactile sensor front plates 1 to 7 obtained in Examples 1 to 7, the luminous reflectance, luminous transmittance, surface roughness Ra, angle dependency of the reflection color, haze value, and sensitivity of the tactile sensor were measured. Each was measured by the following method. Table 1 shows the configuration and characteristics of each layer of the front plates 1 to 7 for the tactile sensor, and Table 2 shows the measurement results of the above characteristics for the front plate for the tactile sensor.
In Table 1, for the type and configuration of each layer, only the abbreviations are described, for example, “Q1” for “glass substrate Q1”.

(Luminous reflectance)
Using a spectrophotometer (manufactured by Shimadzu Corporation, device name: SolidSpec3700), the spectral reflectance at the surface on the insulating layer side of the front plate for each tactile sensor is measured, and the luminous reflectance is measured from the reflectance according to JIS R3106. (%) Was calculated.
Among these, the measurement results of the reflectance in the wavelength region of 300 to 850 nm for the front plates for the tactile sensor of Examples 1, 3 and 6 are shown in FIGS. 8, 9 and 10, respectively.

(Visibility transmittance)
Using a spectrophotometer (manufactured by Shimadzu Corporation, apparatus name: SolidSpec3700), the spectral transmittance of each tactile sensor front plate was measured. And luminous transmittance (%) was calculated | required according to JISR3106.
Among these, the measurement results of the transmittance in the wavelength region of 300 to 850 nm for the front plates for the tactile sensor of Examples 1 and 6 are shown in FIGS. 11 and 12, respectively.

(Surface roughness Ra)
Using a laser microscope (manufactured by Keyence Co., Ltd., product name “VK-9700”), setting the magnification to 50 times, measuring the surface shape of the surface on the insulating layer side of the front plate for each tactile sensor, JIS Calculated according to B0601.

(Angle dependence of reflection color)
Before each tactile sensor front plate 1-7, the surface on the glass substrate side (the surface opposite to the surface on which the high resistance layer is formed on the glass substrate) is painted black to cancel back reflection. The face plate was placed on a desk with the insulating layer side facing up. Further, a stand of daylight direct fluorescent lamp (manufactured by NEC Corporation, three-wavelength daylight white) was arranged at a height of 40 cm from the desk.
Under the irradiation light from the fluorescent lamp, the surface (insulating layer surface) of the front plate for the tactile sensor was visually observed from various angles, and the change in the color tone of the reflected light depending on the viewing angle was evaluated.

Even if the color tone of the front surface of the tactile sensor front plate is a single color (mainly blue, etc.) or when the visual angle is changed more than 10 degrees, the color tone of the tactile sensor front plate is visually observed from any angle. When the change was gradual, “◯” was assigned, and when the visual angle was changed within a range of 10 degrees or less, the change in the color tone of the surface of the front plate for the tactile sensor was assigned “X”.

(Haze value)
The haze value of each tactile sensor front plate was measured using a haze meter (product name “HZ-1” manufactured by Suga Test Instruments Co., Ltd.).

(Sensitivity of tactile sensor)
In each of the front plates 1 to 7 for the tactile sensor, a copper conductive tape (a tape in which a polyethylene terephthalate film (thickness 10 μm) is attached to a copper foil) is attached to the four sides of the surface on the glass substrate side, and the frequency is around 400 Hz. A voltage of 2 kV was applied.
The surface of the energized tactile sensor front plates 1 to 7 (the surface on the insulating layer side) was traced with the fingertip, and the tactile sensor sensitivity was evaluated in four stages according to the size of the tactile sensed by the fingertip.
In Table 2, 0 to 4 indicate the states of “0: I don't feel at all”, “1: I feel faint but weak”, “2: I feel”, and “3: I feel enough”, respectively.

The applied voltage (2 kV) for sensitivity evaluation was determined as follows.
When the supply voltage from the conductive tape provided on the surface of the front plate for the tactile sensor on the glass substrate side was adjusted between the applied voltage of 750 V and 100 kV, the tactile sensation was exhibited at about 2 kV. Based on this, sensor sensitivity was evaluated.

As is clear from Tables 1 and 2, in the tactile sensor front plates of Examples 1 to 5, the high resistance layer had a surface resistance value of 1 to 100 MΩ / □, and good sensor sensitivity was obtained. . In Examples 1 to 5, the surface of each glass substrate (transparent substrate) on the high resistance layer side has a surface roughness Ra of 0.05 to 0.5 μm, and the surface of the front plate for the tactile sensor is 0. It has a surface roughness Ra of 05 μm or less, has little variation in reflection color, has a good appearance without interference fringes, has a low haze value of 1% or less, and a luminous transmittance of 85%. As described above, it had excellent visibility.

On the other hand, in Example 6, the surface roughness Ra of the surface on the high resistance layer side of the glass substrate (transparent substrate) was less than 0.05 μm, the variation in the reflection color due to the interference fringes was large, and the appearance was inferior. . Further, in Example 7, the surface roughness of the front plate for the tactile sensor exceeds 0.05 μm, the haze value is as high as more than 1%, and the reflection color changes, resulting in visibility and appearance. Both were inferior.

Further, as shown in FIGS. 8 and 9, in the front plate for the tactile sensor of Example 1 and Example 3 in which the surface roughness Ra of the surface on the high resistance layer side of the glass substrate is 0.05 to 0.5 μm, It was confirmed that the change in the reflectance with the change in the wavelength of the irradiation light was suppressed, and the appearance was hardly deteriorated by the interference fringes. On the other hand, as shown in FIG. 10, in the front plate for the tactile sensor of Example 6 in which the surface roughness Ra of the surface on the high resistance layer side of the glass substrate is less than 0.05 μm, the wavelength of the irradiated light changes. The accompanying change in reflectance was large, and the appearance was liable to deteriorate due to diffraction fringes.

Further, as shown in FIG. 11, in the front plate for the tactile sensor of Example 1 in which the surface roughness Ra of the surface on the high resistance layer side of the glass substrate is 0.05 to 0.5 μm, the wavelength change of the irradiation light is changed. 12 is suppressed, whereas the surface roughness Ra of the surface of the glass substrate on the high resistance layer side is less than 0.05 μm, as shown in FIG. The front plate for use had a large variation in light transmittance accompanying a change in the wavelength of irradiation light, and the light transmission stability was poor.

DESCRIPTION OF SYMBOLS 1 ... Front plate for tactile sensors, 2,102 ... Transparent substrate, 3 ... High resistance layer, 4,104 ... Insulating layer, 5,100 ... Touch panel body, 5a ... Transparent electrode, 6 ... Water-repellent layer, 7 ... Barrier layer , 101 ... front plate, 103 ... layer formed on the transparent substrate 102, S1 ... surface of the transparent substrate 2 on the high resistance layer 3 side, S2 ... surface of the insulating layer 4 opposite to the high resistance layer 3 side, S3 ... The interface between the insulating layer 4 and the high-resistance layer 3, S4: the surface on the transparent substrate 2 side of the front plate 1 for tactile sensor, S5: the surface opposite to the insulating layer 4 side of the water repellent layer 6, L1, L2, L4 , L5: reflected light, L3: incident light, X: sensory receptor.

Claims

On the transparent substrate, a high resistance layer and an electrically insulating insulating layer are laminated in this order from the transparent substrate side, a touch sensor front plate,
The high resistance layer has a surface resistance value of 1 to 100 MΩ / □, a refractive index of 1.8 to 2.5, and a thickness of 5 to 50 nm.
The insulating layer has a refractive index of 1.3 to 1.6 and a thickness of 0.5 to 15 μm.
The surface roughness Ra of the surface of the transparent substrate on the high resistance layer side is 0.05 to 0.5 μm,
A front plate for a tactile sensor, wherein the surface roughness Ra of the surface on the insulating layer side of the front plate for a tactile sensor is 0.05 μm or less.
The front plate for a tactile sensor according to claim 1, wherein the insulating layer is a layer mainly composed of an organic resin.
The front plate for a tactile sensor according to claim 1 or 2, wherein the high resistance layer is a layer mainly composed of a metal oxide.
4. The front plate for a tactile sensor according to claim 1, wherein a barrier layer is interposed between the transparent substrate and the high resistance layer.
The front plate for a tactile sensor according to any one of claims 1 to 4, wherein the insulating layer is disposed on an upper surface of the high-resistance layer that has been subjected to an adhesion treatment.
The front plate for a tactile sensor according to any one of claims 1 to 5, wherein the haze value is 1% or less.