JP2014241353A - Band selection transparent shield, manufacturing method of band selection transparent shield, display device using the same and display apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of a conventional transparent shield using a metal mesh, which has a high attenuation factor in a wide frequency band, attenuates not only electromagnetic noises in a low frequency band but also electromagnetic signals in a high frequency band such as wireless LAN.SOLUTION: A band selection transparent shield 103 includes: a transparent base material 104; a transparent conductive film 105 formed on the surface of the transparent base material 104, which contains metal nanowires 107; and a light absorption layer 106 containing pigment, which is formed on the transparent conductive film 105. The band selection transparent shield 103 has the sheet resistance of 5 Ω/square or more 200 Ω/square or less; the attenuation factor S2 in a frequency (F2) 10 times higher than the frequency (Fsmax) which represents a maximum attenuation factor (Smax) is smaller than the maximum attenuation factor (Smax) in a range of 10 dB or more 25 dB or less.

Description

  The present invention relates to a band-selective transparent shield, a method for manufacturing the band-selective transparent shield, a display device using the same, and a display device.

  In recent years, tablet terminals and the like are becoming widespread. Such a tablet terminal has a thin casing made of resin, metal, or the like, and a display portion with a touch panel attached to substantially the entire surface of one or more sides of the casing. As such a touch panel (sometimes called TTP), a resistive touch panel has been used.

  Since such a resistive touch panel has a problem that it is easily affected by static electricity, it has been proposed to use an electromagnetic shield using metal nanowires in order to reduce the influence of static electricity on the resistive touch panel. (Patent Document 1). This is because the position detection principle of the resistive touch panel is sensitive to the influence of static electricity, because the position detection is performed by using a plurality of electrodes that face each other in an insulated state to be energized by physical electrical contact. is there. As described above, the resistance touch panel has a problem that it is easily affected by static electricity, but is not affected by electromagnetic noise generated from a display portion (for example, a display portion such as a liquid crystal or an EL). This is because the resistive touch panel utilizes an electrical ON / OFF phenomenon. However, such a conventional resistive touch panel has a problem that it is difficult to simultaneously detect a plurality of positions (for example, multi-touch such as 2-point touch or 5-point touch).

  In order to solve the problem of the resistance type touch panel, a new type touch panel such as a capacitance type corresponding to multi-touch has been developed. The position detection principle of such a capacitive type touch panel is based on the application of a low AC voltage of, for example, several hundred KHz to the matrix-like transparent conductive film constituting the touch panel, so that the human body (or fingertip) made of a dielectric material is touched by the touch panel. A weak current flowing through the human body (or fingertip) is detected by touching and approaching. Thus, the capacitive touch panel needs to detect a weak current in a frequency band of several hundreds KHz, and has a problem that it is easily affected by external noise. In order to solve these problems, an ITO film (ITO is an oxide transparent conductor such as In-Sn oxide) between a display portion (for example, a display portion such as liquid crystal or EL) and a capacitive touch panel. It has been proposed that a conductive layer for shielding is provided (Patent Document 2). However, it is difficult to reduce the resistance of ITO, and it has a problem that it is curled when it is formed on a transparent resin film or the ITO film is easily broken.

  On the other hand, in order to obtain a high electromagnetic shielding effect, by using short metal nanowires having a long axis of 450 nm to 1500 nm, a short axis of 1 to 45 nm, and a fiber length of 1.5 μm or less, the surface resistance is 1.0 Ω / □. The following electromagnetic shielding filter has been proposed (Patent Document 3).

  Furthermore, a transparent shield using a metal mesh has been commercially available. FIG. 11 is a cross-sectional view showing an example of the structure of a conventional transparent shield 1. A conventional transparent shield 1 includes a transparent base part 2 made of a glass substrate or a film, and a thin film metal mesh part 4 formed on the transparent base part 2 via a blackening part 3 (Patent Document). 4).

  FIGS. 12A and 12B are characteristic diagrams showing an example of shield characteristics of the conventional electromagnetic shield shown in FIG. In FIG. 12A, the X-axis is the frequency (unit is MHz), and the Y-axis is the electric field attenuation factor (unit is dB). In FIG. 12B, the X axis is frequency (unit is MHz), and the Y axis is magnetic field attenuation rate (unit is dB).

  As shown in FIG. 12 (A), the conventional electromagnetic shield has an excellent electric field attenuation factor that can maintain an excellent electric field attenuation factor of about 50 dB in a frequency range of at least 1 MHz to 300 MHz. . Furthermore, in FIG. 12A, it can be seen that the conventional electromagnetic shield has an excellent electric field attenuation factor of about 60 dB at the maximum in the frequency range of 300 MHz to 1000 MHz.

  Also, as shown in FIG. 12B, the conventional electromagnetic shield has a magnetic attenuation factor gradually increasing from 0 dB to 30 dB in the frequency range of at least 0.1 MHz to 100 MHz, and a frequency of 100 MHz to 1000 MHz. In the region, it has an excellent magnetic field attenuation factor of about 35 dB.

  On the other hand, recent tablet terminals are required to improve the display image quality (high resolution, high vision, 2K4K, and higher display gradation bit) made of liquid crystal, EL, or the like. As a result, a part of the electromagnetic waves generated from the liquid crystal, EL, or the like may be a kind of noise that causes the touch panel to malfunction.

  Furthermore, the touch panel side responds to higher resolution, higher multi-touch at 10 or more locations, higher accuracy of touch position detection, shorter touch position detection, and high-speed change of touch position as display images become more functional. Etc., there is a demand for higher functionality.

  In order to reduce the thickness of the device, when the proximity of the display part such as liquid crystal or EL that is a noise generation source and the touch panel is required, the touch panel due to a part of electromagnetic noise generated from the display part is likely to malfunction. It becomes easy to generate the problem. Therefore, it is required to provide a transparent electromagnetic shield having high electromagnetic shielding properties between the touch panel and the display portion so that electromagnetic noise generated from the display portion does not propagate to the touch panel.

  On the other hand, in recent tablet terminals (notebook computers and the like are also a kind of tablet terminal), a wireless LAN or WiFi (registered trademark) (WiFi is used by the Wifi Alliance for signal exchange and power exchange with the outside. Interconnection using devices that use the IEEE 802.11 standard, which is an international standard), NFC (NFC is one of the international standards for wireless communication known as Near Field Communication), wireless power supply (wireless power supply is not One of the contact power transmission means) is widely used. In tablet terminals (or display devices used in tablet terminals or the like), wireless communication of 1000 MHz or more and 2 GHz or less is used for signal exchange and power exchange with the outside. In tablet terminals and display devices, an antenna unit and a transmitter / receiver unit provided for exchanging signals and electric power with the outside are built in the housing of the device. Therefore, in such a display device, it may be necessary to exchange signals and power with the outside via a display portion or a touch panel.

  For this reason, when an electromagnetic shield is provided between the display portion and the touch panel, as shown in FIGS. 12A and 12B and the like, an electromagnetic shield is expected at several hundred MHz that causes a malfunction of the touch panel. There is a possibility that signal exchange and power exchange with the outside in the above high frequency range will have an effect.

Special table 2010-507199 JP 2009-98834 A JP 2004-196923 A Japanese Patent Laid-Open No. 11-12604

  As described above, the conventional resistive touch panel is hardly affected by electromagnetic noise, but the recent capacitive touch panel capable of multi-touch has been easily affected by electromagnetic noise.

  In a touch panel that is susceptible to the influence of electromagnetic noise, such as a capacitive type, when a conventional electromagnetic shield is used, a high attenuation rate in a frequency range of 1000 MHz or more affects signal transmission / reception and power transmission / reception with the outside. It is conceivable that this problem occurs.

  The present invention solves such problems, and as a transparent shield provided between a touch panel that is susceptible to electromagnetic noise, such as a capacitance type, and a liquid crystal panel that generates electromagnetic noise, the frequency of the attenuation factor. It has a high selectivity in the low frequency band that has a dependency, that is, a capacitive touch panel, but has a low selectivity in a high frequency band such as 1000 MHz or more. An object is to provide a band-selective transparent shield, a display device with the band-selective transparent shield, and a display device.

  A band-selective transparent shield according to one embodiment of the present invention includes a transparent base material, a transparent conductive film containing metal nanowires on the surface of the transparent base material, and light having a dye formed on the transparent conductive film. A band-selective transparent shield including an absorption layer, having a sheet resistance of 5Ω / □ or more and 200Ω / □ or less, and attenuation at a frequency (F2) that is 10 times higher than a frequency (Fsmax) that exhibits a maximum attenuation rate (Smax). The rate S2 is a band-selective transparent shield that is smaller in the range of 10 dB to 25 dB than the maximum attenuation rate (Smax), and by giving the frequency dependency to the attenuation rate of the transparent shield, a liquid crystal panel for an electrostatic touch panel, etc. The electromagnetic shield noise is selectively cut and the attenuation factor of the transparent shield is reduced in the high frequency range of 100 MHz or higher or 1 GHz or higher. Thus, the high frequency communication characteristics between the outside in the high frequency range of 100 MHz or higher or 1 GHz or higher and the inside of the display device can be enhanced.

  Another example of the band-selective transparent shield that is one embodiment of the present invention is formed on a transparent base material, a transparent conductive film containing metal nanowires on the surface of the transparent base material, and the transparent conductive film. A band-selective transparent shield including a light-absorbing layer having a dye, having a sheet resistance of 5Ω / □ or more and 200Ω / □ or less, and a maximum attenuation rate (Smax) measured by the KEC method of 20 dB or more and 70 dB or less. The frequency (Fsmax) indicating the maximum attenuation rate (Smax) measured by the KEC method is a band-selective transparent shield that is in the band of 1 MHz to 30 MHz, and depends on the attenuation rate of the transparent shield. In addition to actively cutting electromagnetic noise leaking from the liquid crystal panel in the frequency band, which is a problem for electrostatic touch panels, By reducing the attenuation rate of the transparent shield above or in the high frequency range of 1 GHz or higher, the high frequency communication characteristics between the outside in the high frequency range of 100 MHz or higher or 1 GHz or higher and the inside of the display device can be enhanced.

  Another example of the band-selective transparent shield that is one embodiment of the present invention is formed on a transparent base material, a transparent conductive film containing metal nanowires on the surface of the transparent base material, and the transparent conductive film. A band-selective transparent shield comprising a light-absorbing layer having a dye, wherein the haze value measured from the light-absorbing layer side is smaller than the haze value measured from the transparent substrate side, and is a frequency of at least 100 MHz to 1000 MHz A band-selective transparent shield in which the attenuation rate decreases as the frequency increases within a range of 20 dB to 70 dB in a band, and the liquid crystal panel for an electrostatic touch panel has a frequency dependency on the attenuation rate of the transparent shield. Transparent shield in high frequency range of 100MHz or higher or 1GHz or higher. By reducing the attenuation factor, and the external at 100MHz or higher or 1GHz or high frequency range, it is possible to increase the RF communication characteristics of the internal display device.

  An example of a method for producing a band-selective transparent shield according to one aspect of the present invention is a preparation step of preparing a transparent base material, and applying and forming a transparent conductive film containing metal nanowires on the surface on one or more surfaces of the transparent base material The sheet resistance is 5 Ω / □, comprising: a transparent conductive film forming step, and a light absorbing layer forming step of coating and forming a light absorbing layer having a pigment on the transparent conductive film with a thickness of 0.5 μm to 300 μm. The attenuation rate S2 at a frequency (F2) which is 200Ω / □ or less and 10 times higher than the frequency (Fsmax) indicating the maximum attenuation rate (Smax) is smaller than the maximum attenuation rate (Smax) in the range of 10 dB to 25 dB. A band-selective transparent shield having a frequency dependence on the attenuation factor is obtained by using this manufacturing method. It can be produced at low cost by.

  An example of a display device according to an aspect of the present invention includes an image display panel unit or an electrostatic touch panel, and a band selection transparent shield provided on one or more surfaces of the image display panel unit or the electrostatic touch panel. The sheet resistance of the band-selective transparent shield is 5Ω / □ or more and 200Ω / □ or less, and the frequency (F2) is 10 times higher than the frequency (Fsmax) that exhibits the maximum attenuation rate (Smax). The attenuation rate S2 is a display device that is smaller than the maximum attenuation rate (Smax) in the range of 10 dB to 25 dB, actively cuts electromagnetic noise in the display device, and transparent shield in a high frequency range of 100 MHz or more or 1 GHz or more. By reducing the attenuation factor of 100 MHz or more or 1 GHz or more The high frequency communication characteristic between the outside in the high frequency region and the inside of the display device is enhanced.

  An example of a display device according to one embodiment of the present invention includes at least a housing, at least one of an antenna unit and a transceiver unit built in the housing, and an image display panel unit provided on one or more sides. A band-selective transparent shield formed on the image display panel unit, and an electromagnetic shield type touch panel unit formed on the band-selective transparent shield, the band-selective transparent The sheet resistance of the shield is 5Ω / □ or more and 200Ω / □ or less, and the attenuation rate S2 at a frequency (F2) 10 times higher than the frequency (Fsmax) indicating the maximum attenuation rate (Smax) is higher than the maximum attenuation rate (Smax). It is a small display device in the range of 10 dB or more and 25 dB or less, and the liquid crystal panel for the electrostatic touch panel is provided by giving the frequency dependency to the attenuation factor of the transparent shield. In addition to actively cutting electromagnetic noise from the antenna, etc., and reducing the attenuation factor of the transparent shield in the high frequency range of 100 MHz or higher or 1 GHz or higher, the outside in the high frequency range of 100 MHz or higher or 1 GHz or higher, This enhances the high-frequency communication characteristics.

  According to the present invention, the transparent shield actively cuts electromagnetic noise from a liquid crystal panel or the like for an electrostatic touch panel, and reduces the attenuation factor of the transparent shield in a high frequency range of 100 MHz or higher or 1 GHz or higher. High frequency communication characteristics between the outside in the high frequency range of 100 MHz or higher or 1 GHz or higher and the inside of the display device can be improved.

The characteristic view which shows an example of the shield characteristic of the band selection transparent shield of the present invention Sectional drawing explaining the function of the band selection transparent shield built in the equipment (A) (B) is sectional drawing explaining the irregular reflection of the light by metal nanowire both Sectional drawing explaining the scattered light in the metal nanowire surface by the external light in the transparent base material side of a band selection transparent shield Characteristic diagram showing an example of shield characteristics of the band-selective transparent shield produced by the inventors Sectional drawing which shows an example of a display apparatus using a band selection transparent shield Sectional drawing explaining the subject in the display apparatus using the conventional thin film metal mesh part instead of a band selection transparent shield Both (A) and (B) are schematic diagrams for explaining problems that occur when ITO is used as a transparent shield. (A) (B) is sectional drawing which shows an example of the display device which used both the band selection transparent shields. (A) (B) is sectional drawing which shows an example of the display device which used both the band selection transparent shields. Sectional view showing an example of the structure of a conventional transparent shield (A) and (B) are characteristic diagrams showing an example of shield characteristics of a conventional electromagnetic shield.

(Embodiment 1)
In the embodiment, the characteristics of the band selection transparent shield of the present invention will be described with reference to FIG. FIG. 1 is a characteristic diagram showing an example of the shield characteristic of the band selection transparent shield of the present invention. In FIG. 1, the X-axis is frequency (Frequency / MHz), and the Y-axis is attenuation rate (Shield property / dB). 101 is a curve (shield characteristic 101 of the invention) showing the shield characteristic of the band selective transparent shield of the present invention. Reference numeral 102 denotes a curve indicating the shield characteristics of a conventional transparent shield, which is a curve (conventional product shield characteristics 102) measured using the KEC method, and is, for example, the above-described FIG. As shown in FIG. 1, the shield characteristic 102 of the conventional product has a shield characteristic that does not depend on the frequency band and maintains a substantially constant attenuation rate at about 50 dB from near 1 MHz to near 1000 MHz. On the other hand, as shown in FIG. 1, the band selection transparent shield of the present invention has a maximum attenuation rate (Smax, about 53 dB in FIG. 1) between 1 MHz and 10 MHz. As shown in FIG. 1, the band-selective transparent shield has an attenuation rate at a frequency (F2, 80 MHz in FIG. 2) that is 10 times higher than the frequency (Fsmax, about 8 MHz in FIG. 1) indicating the maximum attenuation rate (Smax). S2 has a characteristic (shield characteristic 101 of the invention) that is smaller than the maximum attenuation rate (Smax) in the range of 10 dB to 25 dB (in FIG. 1, smaller by about 15 dB).

  Here, when a frequency 10 times higher than F1 (unit is MHz) is F2 (unit is MHz), that is, “F1 * 10 = F2”, the attenuation rate at frequency F1 (S1) and the attenuation rate at F2 (S2) It is useful as the shield characteristic 101 of the invention that the difference between the values and S1-S2 is 10 dB or more and 25 dB or less.

  Further, when a frequency 100 times higher than F1 (unit is MHz) is F3 (unit is MHz), that is, “F1 * 100 = F3”, the attenuation rate at frequency F3 (S3), the attenuation rate at F2 (S2), It is useful as the shield characteristic 101 of the invention that the difference between the two values, that is, the value of S2-S3 is 10 dB or more and 25 dB or less.

  As described above, the shield property 101 of the invention has an attenuation factor of 10 to 25 dB, more preferably 20 to 50 dB in a high frequency range of 10 times or even 100 times the maximum attenuation rate (Smax). In addition to actively cutting electromagnetic noise from liquid crystal panels, etc. to electrostatic touch panels, and reducing the attenuation factor of the transparent shield in the high frequency range of 100 MHz or higher or 1 GHz or higher, by reducing the size within 100 MHz or higher Or the high frequency communication characteristic between the outside in the high frequency region of 1 GHz or more and the inside of the display device can be enhanced. When the attenuation factor at 10 times is less than 10 dB, or when the attenuation factor at 100 times is less than 20 dB, communication characteristics in the high frequency range may be affected. Alternatively, if the attenuation factor at 10 times is 25 dB or more, or if the attenuation factor at 100 times is 50 dB or more, it is necessary to perform special processing on the transparent shield side, which increases the cost and affects the transmittance. There is a case.

  As described above, when F1 * 10 = F2, or F1 * 100 = F3, and F2 * 10 = F3, S1-S2 = 10 dB to 25 dB, or S2-S3 = 10 dB to 25 dB, and S1-S3 It is desirable that the attenuation rate decreases as the frequency becomes higher, ie, 20 dB or more and 50 dB or less (or a downward-sloping graph in which the attenuation rate decreases in the high frequency region as shown in FIG. 1).

  The structure of the band-selective transparent shield having the characteristics shown in FIG. 1 will be described in the second and third embodiments, FIGS.

  As shown in FIG. 1, the maximum attenuation rate (Smax) of the band-selective transparent shield measured by the KEC method is in the range of 20 dB or more and 70 dB or less. When the maximum attenuation rate (Smax) is less than 20 dB, the shielding property may be affected. If it is higher than 70 dB, it is necessary to perform special processing on the transparent shield side, which may increase the cost or affect the transmittance. The frequency (Fsmax) indicating the maximum attenuation rate (Smax) measured by the KEC method is preferably 0.1 MHz to 30 MHz, more preferably 1 MHz to 20 MHz, and 2 MHz to 10 MHz. When the frequency is less than 0.1 MHz or higher than 30 MHz, the electromagnetic noise attenuation effect on the capacitive touch panel may be affected.

(Embodiment 2)
In the second embodiment, a state in which the band selection transparent shield of the present invention improves the performance of the device will be described with reference to FIG.

  FIG. 2 is a cross-sectional view for explaining the function of the band-selective transparent shield incorporated in the device. In FIG. 2, reference numeral 103 denotes a band selection transparent shield described in the first embodiment. The band selection transparent shield 103 includes at least a transparent substrate 104 made of a resin film such as glass or PET, a transparent conductive film 105, and a light absorption layer 106. The transparent conductive film 105 is formed of at least metal nanowires 107 and a transparent resin (not numbered) that serves as a binder for holding the metal nanowires 107. The light absorption layer 106 is formed of at least one of a light-absorbing dye, carbon, or a conductive polymer, and a transparent resin (not numbered) that serves as a binder for holding these. ing. Reference numeral 109 denotes a liquid crystal panel, for example, IPS, but the liquid crystal panel 109 may be a display panel such as an EL. Reference numeral 110 denotes a touch panel, and the touch panel may be a transparent touch panel having excellent multi-touch properties, and is a capacitive touch panel or the like.

  An arrow 108 a in FIG. 2 shows an example of electromagnetic noise radiated from the liquid crystal panel 109. As shown in the arrow 108a at several hundreds KHz to several MHz by improving the display quality of the liquid crystal, EL, etc. (high resolution, high vision, 2K4K, and high display gradation) Electromagnetic noise is generated. The electromagnetic noise indicated by the arrow 108a is greatly attenuated by the band selection transparent shield 103 as indicated by the arrow 108b. This is because the band selection transparent shield 103 has a frequency of several hundred KHz to several tens MHz as shown in FIG. This is because the region has a high attenuation rate. As a result, electromagnetic noise reaching the touch panel 110 is significantly reduced, and malfunction of the touch panel 110 is reduced.

  An arrow 108 c to an arrow 108 f in FIG. 2 both show a state in which electromagnetic waves of several hundred MHz to several GHz pass through the band selection transparent shield 103. An electromagnetic wave emitted from an antenna or the like (not shown) installed outside the device is shown as an arrow 108b, and an antenna or the like (not shown) installed inside the device via the band-selective transparent shield 103. In this case, even if it passes through the band selective transparent shield 103, the attenuation is small, but this is because the band selective transparent shield 103 has a frequency of several hundred MHz to several GHz as shown in FIG. This is because the attenuation rate is small in the region.

  An arrow 108f indicates that an electromagnetic wave emitted from an antenna or the like (not shown) installed inside the device is an antenna or the like (not shown) installed outside the device via the band selection transparent shield 103. Shows how to reach. As shown by the arrow 108f, even if it passes through the band selective transparent shield 103, the attenuation is small, but as shown in FIG. 1, the band selective transparent shield 103 is in the frequency range of several hundred MHz to several GHz. This is because the attenuation rate is small.

(Embodiment 3)
In the third embodiment, a state in which irregular reflection of light by metal nanowires included in the transparent conductive film 105 constituting the band selection transparent shield 103 is reduced will be described with reference to FIGS.

  3A and 3B are cross-sectional views for explaining irregular reflection of light by metal nanowires.

  FIG. 3A is a cross-sectional view showing a state in which external light is diffusely reflected on the surface of the metal nanowire. As shown in FIG. 3A, when a light absorption layer is not provided on the surface of the band selection transparent shield 103, external light indicated by an arrow 108a is diffusely reflected on the surface of the metal nanowire 107 as indicated by an arrow 108c. , Reduce optical properties such as haze.

  FIG. 3B is a cross-sectional view for explaining how the scattered light on the surface of the metal nanowire 107 is reduced by the light absorption layer 106 having light absorption provided on one surface of the band selection transparent shield 103. As shown in FIG. 3B, scattered light due to external light can be reduced by providing the light absorption layer 106 on the surface of the transparent conductive film 105 including the metal nanowires 107. This is because when external light obliquely crosses the light absorption layer 106 as indicated by an arrow 108a, the light is absorbed and further scattered at the surface of the metal nanowire 107, and the scattered light is absorbed as indicated by an arrow 108c. This is because it is absorbed when traversing the layers diagonally. In order to do this, it is desirable to provide the band selection transparent shield 103 on a side different from the transparent base material 104 side of the transparent conductive film 105. The intensity of the scattered light can be measured as a haze value using a commercially available haze meter or the like.

  In the band selective transparent shield 103, it is useful to make the haze value measured from the light absorption layer 106 side smaller than the haze value measured from the transparent substrate 104 side. Thus, by making the haze value measured from the light absorption layer 106 side smaller than the haze value measured from the transparent substrate 104 side, the thickness of the light absorption layer is reduced, or the light absorption rate of the light absorption layer is increased. Even if it is made low, scattered light can be reduced effectively.

  FIG. 4 is a cross-sectional view for explaining scattered light on the surface of the metal nanowire due to external light on the transparent substrate side of the band-selective transparent shield. As shown in FIG. 4, the external light obliquely traverses the transparent substrate 104 as shown by an arrow 108a and is scattered on the surface of the metal nanowire, and the scattered light passes through the transparent substrate 104 as shown by an arrow 108c. Although it crosses diagonally, it is hardly absorbed during this crossing. If necessary, it is possible to reduce the scattered light indicated by the arrow 108c by coloring the transparent base material 104 and newly providing a light absorption layer on the surface of the transparent base material. Although it is useful to make the haze value measured from the light absorption layer 106 side smaller than the haze value measured from the transparent substrate 104 side, the value from the outside of the display device is important for diffuse reflection or haze. Because.

  The shield characteristics of the band selection transparent shield produced by the inventors will be described in more detail using the third embodiment. FIG. 5 is a characteristic diagram showing an example of the shield characteristic of the band-selective transparent shield produced by the inventors.

  In FIG. 5, the shield characteristic 101a of the invention is the shield characteristic of the band-selective transparent shield (Sample A, sheet resistance is 150Ω / □) produced by the inventors. The shield characteristic 101b of the invention is a shield characteristic of a band-selective transparent shield (Sample B, sheet resistance is 40Ω / □) prepared by the inventors. Both shield characteristics were measured using the KEC method.

  As shown in FIG. 5, the maximum attenuation rate can be increased from about 46 dB to about 55 dB by reducing the sheet resistance from 150Ω / □ to 40Ω / □. Further, by reducing the sheet resistance from 150Ω / □ to 40Ω / □, the frequency indicating the maximum attenuation rate can be moved from F1 (A) to F1 (B).

  As shown in FIG. 5, in the band-selective transparent shield, the frequency is 1 MHz or more, further 10 MHz or more, further 20 MHz or more and 1000 MHz or less, regardless of the change in sheet resistance (range of 150Ω / □ to 40Ω / □). In this frequency band, the tendency that the attenuation rate decreases as the frequency increases within the range of 20 dB to 70 dB does not change. The band-selective shielding effect having such a tendency is manifested in a sheet resistance range of 5Ω / □ or more and 200Ω / □ or less that the inventors have experimented.

  In addition, when the inventors conducted various experiments, when the sheet resistance was reduced to 10Ω / □ or less, further 5Ω / □ or less, and 2.5Ω / □ or less using metal nanowires, the sheet resistance was 10 MHz or more. In some cases, it becomes difficult for band selectivity to occur such that the attenuation rate decreases to the right, or the shield characteristics approach those shown in FIGS. 12A and 12B.

  This is presumably because the sheet resistance is lowered to 5 Ω / □ or less to approach the conventional transparent shield shown in FIGS. 11 and 12.

  The inventors used metal nanowires 107 used for the band-selective transparent shield 103 having an average length of 2 μm or more, more preferably 3 μm or more, 5 μm or more, and 10 μm or more. This is because it is easier to form a sheet resistance region (for example, 5 Ω / □ or more and 200 Ω / □ or less) having band selectivity required by the inventors by using the metal nanowire 107 having the thickness.

  For example, when the average length of the metal nanowire 107 is as short as less than 5 μm or less than 2 μm, it is easy to realize a low sheet resistance of 10Ω / □ or less, 5Ω / □ or less, and the band required by the inventors It may be difficult to form a sheet resistance region having selectivity (for example, 5Ω / □ or more and 200Ω / □ or less). This is because, when the length of the metal nanowire 107 is as short as less than 2 μm, the contact probability between the metal nanowires decreases, and it becomes difficult to stably realize a resistance region of 5Ω / □ or more and 200Ω / □ or less. There is a case. For example, in a transparent conductive film using metal nanowires having an average length of less than 2 μm, in order to obtain conduction by contact between the metal nanowires 107, the basis weight of the metal nanowires (basis weight is JIS P8124 paper and paperboard-tsubo Need to be increased).

  Here, the transparent conductive film produced using the metal nanowire 107 having an average length of less than 2 μm is equivalent to “paper” for example, and the strength as paper can be increased by increasing the thickness. However, when the thickness is reduced, high strength and high yield strength as in Japanese paper cannot be obtained. On the other hand, the transparent conductive film 105 produced using the metal nanowire 107 having an average length of 5 μm or more and 10 μm or more as in the present invention is equivalent to “Japanese paper”, for example, and has excellent curling resistance. (The curl resistance will be described in Table 2 below).

  Thus, it is useful that the transparent conductive film 105 including the metal nanowires 107 used for the band-selective transparent shield 103 of the present invention corresponds to “Japanese paper”. For that purpose, the fiber length is long and the basis weight is low. It is useful to make it easy to obtain conduction due to entanglement between fibers. The band-selective transparent shield 103 thus obtained is durable and has a curl resistance that the sheet resistance does not change even when bent. And the transparent conductive film 105 containing the metal nanowire 107 used for the band selection transparent shield 103 of the present invention increases the contact probability between fibers at a small basis weight, thereby enabling a sheet resistance range of 5Ω / □ or more and 200Ω / □ or less. Can be realized stably without variation.

  Thus, when trying to obtain a sheet resistance range of 5Ω / □ or more and 200Ω / □ or less, which is useful for noise reduction of the touch panel 110, compared to the case of using a short metal nanowire 107 having an average fiber length of 2 μm or less. By using the long metal nanowire 107 having an average fiber length of 5 μm or more, the basis weight can be reduced, which is advantageous in terms of cost. Further, the flexibility (for example, handling property and winding property when continuously coated on a long film) and curling resistance of the transparent conductive film 105 thus obtained are more advantageous as the fiber length is longer.

  As described above, the band-selective transparent shield 103 of the present invention has flexibility such as “Japanese paper”, or proof strength, as well as crack resistance and curl resistance. Even when an inorganic material is used or a flexible transparent organic sheet such as a PET film is used, problems such as cracks and curls do not occur regardless of the coefficient of thermal expansion and flexibility.

(Embodiment 4)
In Embodiment 4, an example of a display device using the band selection transparent shield 103 will be described with reference to FIG.

  FIG. 6 is a cross-sectional view illustrating an example of a display device using the band selection transparent shield described in the first embodiment. In FIG. 6, reference numeral 111 denotes a display device, which is a display device having a display unit such as a smartphone, an electronic tablet, a hospital electronic medical record, an electronic notebook, an electronic book, an electronic blackboard, or a notebook computer.

  The display device 111 includes a housing 112 having a large opening (not assigned a number) in one direction, a liquid crystal panel 109 provided so as to close the opening of the housing 112, a band selection transparent shield 103, A touch panel 110 and the like are included.

  Electromagnetic noise of around several hundred MHz generated from the liquid crystal panel 109 or the like indicated by the arrow 108a in FIG. 6 is attenuated by the band selection transparent shield 103, and thus causes a malfunction of the capacitive touch panel 110. Must not. Note that the touch panel 110 used for the display device 111 may be a capacitance type touch panel or a hover type (non-contact type) touch panel. As shown in FIG. 6, by using the band-selective transparent shield 103 of the present invention, the electrostatic noise or the hover type touch panel that is easily affected by the electromagnetic noise generated from the liquid crystal panel 109 is used. This is because the influence can be prevented.

  In FIG. 6, reference numeral 113 denotes an internal antenna unit. The internal antenna unit 113 is installed in the housing 112 and is used for wireless LAN, WiFi (registered trademark), NFC, and wireless communication that uses a high frequency such as 1 GHz or higher. It is a high-frequency antenna used. Reference numeral 114 denotes an external antenna unit, which is an external antenna unit for wireless LAN, WiFi (registered trademark), NFC, or wireless communication installed outside the housing 112, such as indoors or on the premises. As indicated by arrows 108 d and 108 e in FIG. 6, the electromagnetic wave emitted from the external antenna unit 114 reaches the internal antenna unit 113 with almost no absorption by the band selection transparent shield 103.

  In FIG. 6, reference numeral 115 denotes an internal transmission / reception unit installed inside the housing 112, which is a component used for wireless LAN, WiFi (registered trademark), NFC, and wireless communication using a high frequency such as 1 GHz or higher. . Reference numeral 116 denotes an external transmission / reception unit, which is a wireless LAN, WiFi (registered trademark), NFC, or wireless communication device installed outside the housing 112, such as indoors or on the premises. As indicated by arrows 108 f and 108 g in FIG. 6, a high frequency wave of 1 GHz or more emitted from the internal transmission / reception unit 115 reaches the external transmission / reception unit 116 with almost no absorption by the band selection transparent shield 103.

  FIG. 7 is a cross-sectional view for explaining a problem in a display device using a conventional thin film metal mesh portion instead of the band-selective transparent shield. As shown in FIG. 7, when the conventional thin film metal mesh portion 4 (for example, the one described in FIG. 11 described above) is provided between the liquid crystal panel 109 and the touch panel 110, the conventional thin film metal mesh portion 4 is provided. However, at the same time as removing the electromagnetic noise generated from the liquid crystal panel 109, communication between the internal antenna unit 113 and the external antenna unit 114 indicated by the arrow 108a, or between the internal transmission / reception unit 115 and the external transmission / reception unit 116 indicated by the arrow 108b. Communication may be greatly hindered. As shown in FIG. 12 described above, in the case of a transparent shield using a conventional metal mesh or a special metal nanowire having a low resistance of about 1 Ω / □, high electromagnetic attenuation is achieved even at 100 MHz or higher, and even in the vicinity of 1000 MHz. It is because it has a rate.

(Embodiment 5)
A problem that occurs when a transparent conductive film using conventional ITO is used as the transparent shield will be described using the fifth embodiment.

  FIGS. 8A and 8B are schematic diagrams for explaining a problem that occurs when ITO is used as a transparent shield. 117a and 117b are both ITO films. 118 is a crack or the like.

  When producing a transparent shield using ITO using a roll-shaped resin film, as shown in FIG. 8A, the transparent shield made of the film with ITO 117a is curled, and cracks 118 and the like are generated on the surface. In some cases, this is because the coefficient of thermal expansion differs greatly between the film made of organic matter and the ITO made of oxide. Problems such as curl and crack 118 are likely to occur when the ITO film thickness is increased or heat treatment is performed in order to realize a low resistance of the ITO thin film of 300Ω / □ or less.

  FIG. 8B is a perspective view for explaining an example of a problem in the transparent shield of the ITO single wafer. As shown in FIG. 8B, even in the case of a single wafer, the transparent shield made of the ITO-attached film 117b is likely to generate cracks 118 and the like, but the film made of organic matter and the oxide made of ITO Such a curl (not shown), a crack 118, or the like may occur due to a large difference in thermal expansion coefficient. Such a problem is likely to occur when the ITO film thickness is increased or the heat treatment is performed at 100 ° C. or higher in order to realize a low resistance of the ITO thin film of 150Ω / □ or less.

  When the ITO film thickness is increased, the transparent shield itself using ITO is colored (for example, yellow or metallic metallic luster, etc.), which causes a problem of lowering the light transmittance itself. Therefore, when ITO is used, it is difficult to realize a low resistance of 150Ω / □ or less and 100Ω / □ or less, but this is not only the problem that the crack 118 described above is likely to occur (or easily curl), This is because a coloring problem caused by ITO occurs.

(Embodiment 6)
An example of a display device using a band-selective transparent shield will be described using Embodiment 6 with reference to FIGS.

  9A and 9B are cross-sectional views showing an example of a display device using a band-selective transparent shield. For example, the display device 119 includes a band selection transparent shield 103 provided on one surface of the capacitive touch panel 110. Here, the display device 119 may be a device related to display, and the touch panel is also a form of the display device. 9A and 9B, 119 is a display device, and 120 is an adhesive layer.

  As shown in FIG. 9A, the display device 119 has at least one band-selective transparent shield 103 having a transparent base material 104, a transparent conductive film 105, a light absorbing layer 106, and an adhesive layer 120 on at least one surface thereof. ing. Then, the band-selective transparent shield 103 having the adhesive layer 120 or the like is attached to one surface of the touch panel 110 as indicated by an arrow 108, whereby the display device 119 is obtained. The adhesive layer 120 only needs to have adhesion to the touch panel 110 or the like, and may be a transparent optical material such as a gel.

  FIG. 9B is a cross-sectional view illustrating an example of a display device 119 provided with a band selection transparent shield 103 having band selectivity on one surface. By using the display device 119 as shown in FIG. 9B, a display device 119 having a touch panel function that is hardly affected by external electromagnetic waves and has few malfunctions can be realized.

  FIGS. 10A and 10B are cross-sectional views showing an example of a display device using a band-selective transparent shield. For example, the display device includes a band-selective transparent shield 103 provided on one surface of a liquid crystal panel.

  As shown in FIG. 10A, the display device 119 can be manufactured. For example, as shown in FIG. 10A, a band-selective transparent shield 103 having at least a transparent base material 104, a transparent conductive film 105, a light absorption layer 106, and an adhesive layer 120 is prepared. The display device 119 is attached to one surface of the liquid crystal panel 109.

  FIG. 10B is a cross-sectional view illustrating an example of a display device in which a band selection transparent shield having band selectivity is provided on one surface. With the display device 119 as shown in FIG. 10B, the display device 119 having a display function with less electromagnetic noise emission to other electronic devices can be realized.

(Embodiment 7)
The metal nanowire used for this invention is demonstrated using Embodiment 7. FIG. As the metal nanowire 107 used in the present invention, the one proposed by the inventors in Japanese Patent Application No. 2009-174594 can be used.

  Here, the manufacturing method of the metal nanowire 107 is not particularly limited, and for example, a known method such as a liquid phase method or a gas phase method can be used. There is no restriction | limiting in particular also in a specific manufacturing method, A well-known manufacturing method can be used. For example, as a method for producing Ag nanowires, Adv. Mater. 2002, 14, P833-837, Chem. Mater. 2002, 14, P4736-4745, the above cited reference 2 and the like, as a method for producing Au nanowire, JP 2006-233252A and the like, as a method for producing Cu nanowire, JP 2002-266007 A and the like, As a method for producing Co nanowires, JP-A No. 2004-148771 can be cited. In particular, the above Adv. Mater. And Chem. Mater. The method for producing Ag nanowires reported in 1) can produce Ag nanowires easily and in large quantities in an aqueous system, and since the conductivity of silver is the largest among metals, production of metal nanowires used in the present invention It can be preferably applied as a method.

  In the present invention, the average diameter of the metal nanowires 107 is preferably 200 nm or less from the viewpoint of transparency, and preferably 10 nm or more from the viewpoint of conductivity. It is preferable that the average diameter is 200 nm or less because a decrease in light transmittance can be suppressed. On the other hand, if the average diameter is 10 nm or more, the function as a conductor can be expressed significantly, and a larger average diameter is preferable because conductivity is improved. Therefore, the average diameter is more preferably 20 to 150 nm, and further preferably 40 to 150 nm. The average length of the metal nanowires 107 is preferably 1 μm or more from the viewpoint of conductivity, and preferably 100 μm or less from the viewpoint of the effect on the transparency due to aggregation. More preferably, it is 1-50 micrometers, and it is still more preferable that it is 3-50 micrometers. The average diameter and average length of the metal nanowires 107 can be obtained from the arithmetic average of the measured values of individual metal nanowire images by taking electron micrographs of a sufficient number of nanowires using SEM or TEM. The length of the metal nanowires should be obtained in a state where the metal nanowires are originally stretched in a straight line. However, in reality, the lengths of the metal nanowires are often bent. The projected area is calculated and calculated assuming a cylindrical body (length = projected area / projected diameter). The number of metal nanowires to be measured is preferably at least 100 or more, and more preferably 300 or more metal nanowires.

  The metal nanowire 107 is used by being dispersed in a resin solution. As a resin component for forming a film of the resin solution, a resin component that forms a matrix by polymerization of monomers or oligomers is used. .

  When using a resin that undergoes a photopolymerization reaction or a thermal polymerization reaction as the above resin component, a monomer that undergoes a polymerization reaction directly or under the action of an initiator by irradiation with visible light, ionizing radiation such as ultraviolet rays or electron beams Or an oligomer can be used and the monomer or oligomer which has an acryl group or a methacryl group is suitable. Among them, a polyfunctional binder component is preferable in order to increase the scratch resistance and hardness by crosslinking.

  As one having one functional group in one molecule, specifically, for example, isoamyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxy-diethylene glycol (meta ) Acrylate, methoxy-triethylene glycol (meth) acrylate, methoxy-polyethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxy-polyethylene glycol ( (Meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, (meth) acrylic acid, 2- (meth) acryloyloxyethyl-succinic acid, 2- (meth) acryloyloxyethyl Phthalic acid, isooctyl (meth) acrylate, isomyristyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate Cyclohexyl methacrylate, benzyl (meth) acrylate, (meth) acryloylmorpholine, and the like.

  As those having two or more functional groups, specifically, for example, polyethylene glycol diacrylate, glycerin triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, diester Examples thereof include pentaerythritol hexaacrylate, alkyl-modified dipentaerythritol hexaacrylate, and the compounds having a benzene ring include ethylene oxide-modified bisphenol A diacrylate, modified bisphenol A diacrylate, ethylene glycol diacrylate, and ethylene oxide propylene oxide modified. Bisphenol A diacrylate, propylene oxide tetramethylene oxa De-modified bisphenol A diacrylate, bisphenol A- diepoxy - acrylic acid adduct, ethylene oxide-modified bisphenol F diacrylate, and polyfunctional acrylates or methacrylates such as polyester acrylates.

  1,2-bis (meth) acryloylthioethane, 1,3-bis (meth) acryloylthiopropane, 1,4-bis (meth) acryloylthiobutane, 1,2-bis (meth) acryloylmethylthiobenzene, The use of sulfur-containing (meth) acrylates such as 1,3-bis (meth) acryloylmethylthiobenzene is also effective for increasing the refractive index.

  Further, a light or thermal polymerization initiator may be blended in order to promote curing by ultraviolet rays or heat.

  Although what is generally marketed may be used as a photoinitiator, when it illustrates especially, benzophenone, 2, 2- dimethoxy- 1, 2- diphenyl ethane- 1-one (Ciba Specialty Chemicals Co., Ltd. product " Irgacure 651 "), 1-hydroxy-cyclohexyl-phenyl-ketone (" Irgacure 184 "manufactured by Ciba Specialty Chemicals), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Ciba Specialty Chemicals "Darocur 1173", Lamberti "Esacure KL200"), Oligo (2-hydroxy-2-methyl-1-phenyl-propan-1-one) (Lamberti "Esacure KIP150" "), 2-hydroxyethyl-phenyl-2-hydride Xyl-2-methyl-1-propan-1-one (“Irgacure 2959” manufactured by Ciba Specialty Chemicals Co., Ltd.), 2-methyl-1 (4- (methylthio) phenyl) -2-morpholinopropane-1 -ON ("Irgacure 907" manufactured by Ciba Specialty Chemicals Co., Ltd.), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (Ciba Specialty Chemicals Co., Ltd. " Irgacure 369 "), bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (" Irgacure 819 "manufactured by Ciba Specialty Chemicals Co., Ltd.), bis (2,6-dimethoxybenzoyl) -2,4 , 4-Trimethyl-pentylphosphine oxide (Ciba Specialty Chemical) "CGI403" manufactured by KK Thioxanthone or a derivative thereof, and the like can be used, and one or a mixture of two or more of these can be used.

  Further, a tertiary amine such as triethanolamine, ethyl-4-dimethylaminobenzoate, isopentylmethylaminobenzoate or the like may be added for the purpose of photosensitization.

  As a polymerization initiator by heat, a peroxide such as benzoyl peroxide (= BPO) or an azo compound such as azobisisobutylnitrile (= AIBN) is mainly used.

  The blending amount of the photopolymerization initiator and the thermal polymerization initiator is usually preferably about 0.1 to 10 parts by mass with respect to 100 parts by mass of the composition (resin component + metal nanowire).

  Moreover, you may use the monomer or oligomer which has cationic polymerizable functional groups, such as an epoxy group, a thioepoxy group, and an oxetanyl group. Further, if necessary, a photocationic initiator or the like can be used in combination. These are likewise preferably polyfunctional.

  Moreover, about resin to thermally polymerize, generally sol-gel type material is mentioned, Sol-gel type materials, such as alkoxysilane and alkoxytitanium, are preferable. Of these, alkoxysilane is preferred. The sol-gel material forms a polysiloxane structure. Specifically, the alkoxysilane includes tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, Methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3 -Glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyl Trialkoxysilanes such as reethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, 3,4-epoxycyclohexylethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane , Diethyldimethoxysilane, diethyldiethoxysilane and the like. These alkoxysilanes can be used as a partial condensate thereof. Among these, tetraalkoxysilanes or partial condensates thereof are preferable. In particular, tetramethoxysilane, tetraethoxysilane or a partial condensate thereof is preferable.

  Furthermore, a conductive polymer can also be used as a resin component that forms the matrix of the resin solution. Examples of the conductive polymer include polyaniline, polypyrrole, polythiophene, polytriphenylamine and the like.

  Moreover, as a resin component which forms the matrix of a resin solution, you may use together two or more types selected from the above-mentioned photopolymerizable resin, thermopolymerizable resin, and conductive polymer.

  The compounding amount of the metal nanowires 107 in the resin solution is such that when the transparent conductive film is formed as described later, the metal nanowires 107 are contained in an amount of 0.01 to 90% by mass in the transparent conductive film. It is preferable to adjust and set the compounding quantity with respect to the resin component. As for content of metal nanowire, 0.1-30 mass parts is more preferable, More preferably, it is 0.5-10 mass%.

  Here, it is essential that the resin solution contains a solvent for dissolving or dispersing solid components such as resin solids and metal nanowires 107, but the type of the solvent is not particularly limited. For example, alcohols such as methanol, ethanol and isopropyl alcohol; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; halogenated hydrocarbons; aromatic hydrocarbons such as toluene and xylene Or mixtures thereof can be used. Among these, it is preferable to use a ketone-based organic solvent. When a resin solution is prepared using a ketone-based solvent, it can be easily and uniformly applied to the surface of the transparent substrate, and the solvent after coating. Since the evaporation rate is moderate and it is difficult to cause uneven drying, a transparent conductive film having a uniform area and a large area can be easily obtained. In addition to the above organic solvent, water may be used as the solvent, or an organic solvent and water may be used in combination. The amount of the solvent can uniformly dissolve and disperse each of the above solid components so that the concentration does not cause aggregation during storage after preparing the resin solution and is not too dilute during coating. Adjust as appropriate. Prepare a high-concentration resin solution by reducing the amount of solvent used within the range that satisfies this condition, store it in a state that does not take up the volume, take out the necessary amount at the time of use, and adjust the solvent to a concentration suitable for coating work. It is preferable to dilute with. When the total amount of the solid content and the solvent is 100 parts by mass, the amount of the solvent is preferably set to 50 to 99.9 parts by mass with respect to 0.1 to 50 parts by mass of the total solids, and more preferably By using 70 to 99.5 parts by mass of the solvent with respect to 0.5 to 30 parts by weight of the total solid content, a resin solution that is particularly excellent in dispersion stability and suitable for long-term storage can be obtained. . The combination of the resin and the solvent to be used is not particularly defined, but it is preferable to use a solvent in which the compounded resin is easily dissolved. Further, depending on the transparent substrate to be coated, dissolution may occur depending on the solvent used. Therefore, it is desirable to design an appropriate solvent composition after confirming the solubility in the transparent substrate in advance.

  On the other hand, in the transparent base material 104 used by this invention, there is no restriction | limiting in particular about the shape, a structure, a magnitude | size, etc., According to the objective, it can select suitably. Examples of the shape of the transparent substrate include a flat plate shape, a sheet shape, and a film shape, and the structure may be, for example, a single layer structure or a laminated structure, and may be appropriately selected. Can do. There is no restriction | limiting in particular also about the material of a transparent base material, Any of an inorganic material and an organic material can be used suitably. Examples of the inorganic material forming the transparent substrate include glass, quartz, and silicon. Examples of organic materials include acetate resins such as triacetyl cellulose (TAC); polyester resins such as polyethylene terephthalate (PET); polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, and polyimides. Resin, polyolefin resin, acrylic resin, polynorbornene resin, cellulose resin, polyarylate resin, polystyrene resin, polyvinyl alcohol resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyacrylic resin Etc. These may be used individually by 1 type and may use 2 or more types together.

  In the present invention, the transparent substrate 104 may be a single substrate as described above, but may be one in which one or more hard coat layers are formed on the surface of the substrate. . Thus, when a transparent base material is provided with a hard-coat layer, a transparent conductive film is formed on a hard-coat layer.

  The hard coat layer may be formed of a resin obtained by polymerizing a monomer, and particles or the like may be included in the resin. The resin is not particularly limited, but the same resin as the matrix-forming resin for forming the transparent conductive film can be used, and the particles have a lower refractive index or higher refractive index than the resin. Those having various functions such as those having higher hardness than resin, those having higher heat resistance, and the like can be used.

  Then, a transparent conductive film 105 as shown in FIG. 4 or the like can be formed by applying a resin solution containing the above-mentioned metal nanowires to the surface of the transparent substrate 104 and drying and curing the resin solution. In the transparent conductive film 105 thus formed, the metal nanowires 107 are contained in a uniformly dispersed state. Examples of the resin solution coating method include spin coating, casting, roll coating, flow coating, printing, dip coating, casting film formation, bar coating, and gravure printing. The thickness of the transparent conductive film 105 is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably in the range of about 0.01 to 100 μm, more preferably in the range of 0.05 to 10 μm. Is in the range of 0.1 to 3 μm.

  Thus, after forming the transparent conductive film 105 on the surface of the transparent base material 104, the light absorption layer 106 is laminated | stacked and formed on the surface of this transparent conductive film 105.

  The light absorption layer 106 can be formed by dissolving or dispersing a light absorber in a resin solution, applying the resin solution containing the light absorber on the surface of the transparent conductive film 105, and drying and curing.

  As the matrix resin and the solvent constituting the resin solution, the same resin solution as that described above for forming the transparent conductive film 105 can be used.

  As the light absorber, carbon, a dye, a conductive polymer, or the like can be used. Since these light absorbers have high light absorption efficiency, the light absorption layer 106 can be formed thin with a small amount of use. Therefore, the light absorption layer 106 can suppress a decrease in surface resistance and light transmittance of the transparent conductive film.

  Examples of the dye include monoazo pigment, quinacridone, iron oxide yellow, disazo pigment, phthalocyanine green, phthalocyanine blue, cyanine blue, flavanthrone yellow, dianthraquinolyl red, indanthrone blue, thioindigo bordeaux, and perinone. Orange, perylene scarlet, perylene red 178, perylene maroon, dioxazine violet, isoindolinone yellow, quinophthalone yellow, isoindoline yellow, nickel nitroso yellow, madder lake, copper azomethine yellow, aniline black, alkali blue, petite, chromium oxide, Iron black, titanium yellow, cobalt blue, cerulean blue, cobalt green, viridian, cadmium yellow, cadmium red, vermilion Organic and inorganic pigments such as yellow lead, molybdate orange, zinc chromate, ultramarine, manganese violet, cobalt violet, emerald green, carbon black, azo dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes And methine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, naphthalimide dyes, and verinone dyes.

  The conductive polymer may be a dye. Examples of conductive polymers as colored or organic colored resins include polymer chains conjugated with π electrons derived from benzene rings and five-membered rings, specifically polythiophene-based, polypyrrole-based, polyaniline-based, etc. However, these π-electron conjugated systems are not limited to those listed here.

  The light absorbers exemplified above can be used alone or in combination of two or more.

  It is preferable to set the compounding quantity with respect to the resin solution of a light absorber in the range of 0.01-20 mass% with respect to the resin component, More preferably, it is 0.1-10 mass%.

  Examples of a method for applying a resin solution containing a light absorber on the surface of the transparent conductive film 105 include spin coating, casting, roll coating, flow coating, printing, dip coating, and cast film formation. Method, bar coating method, gravure printing method and the like. The thickness of the light absorption layer 106 is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably in the range of about 0.01 to 5 μm, and more preferably in the range of 0.1 to 1 μm.

  The transparent conductive film 105 formed as shown in FIG. 2 and FIG. 3B in this way exhibits high conductivity due to the metal nanowires 107 contained in the transparent conductive film 105. In addition, since the light absorption layer 106 is formed on the surface of the transparent conductive film 105, most of the light incident on the transparent conductive film 105 can be absorbed by the light absorption layer 106, and the metal nanowires in the transparent conductive film 105 can be absorbed. The amount of light reaching 107 can be reduced, and haze caused by the light being dispersed by the metal nanowire 107 can be reduced.

  Further, if a part of the metal nanowire 107 is exposed on the surface of the transparent conductive film 105, the surface smoothness of the transparent conductive film 105 may be hindered by the metal nanowire 107. For example, a device such as a touch panel requires a contact function on the surface, and a transparent conductive film such as an organic EL requires a surface bonding function for receiving charges on the surface. Smoothness is often important. However, in the present invention, since the surface of the transparent conductive film 105 is covered with the light absorbing layer 106, the surface can be smoothed with the light absorbing layer 106 to obtain high surface smoothness. The combined function can be improved.

  The use of the substrate with a transparent conductive film according to the present invention obtained as described above is not particularly limited, but is applicable to organic EL elements, transparent wiring, photoelectric conversion elements, electromagnetic wave shields, touch panels, electronic papers, and the like. Is something that can be done.

  Next, the silver nanowire used in the present invention will be specifically described with reference to examples.

Example 1
Photocurable acrylic resin (“A-DPH” manufactured by Shin-Nakamura Chemical Co., Ltd.) 18.1 parts by weight, methyl ethyl ketone 8.1 parts by weight and methyl isobutyl ketone 21.8 parts by weight, and a mixture in which the acrylic resin is dissolved A was prepared. Silver nanowires were used as metal nanowires. This silver nanowire was prepared according to a well-known paper “Materials Chemistry and Physics vol. 114 p333-338“ Preparation of Ag nanorods with high yield by polyol process ”” and has an average diameter of 150 nm and an average length of 5 μm. . A mixture B in which 12.0 parts by mass of this metal nanowire was dispersed in 40.0 parts by mass of methyl ethyl ketone was prepared. Then, after thoroughly mixing the mixture A and the mixture B, 0.1 parts by mass of a photopolymerization initiator (“Irgacure 184” manufactured by Ciba Geigy Co., Ltd.) is added and mixed well, and further stirred for 1 hour in a constant temperature atmosphere at 25 ° C. By mixing, the coating material composition which consists of a resin solution containing a metal nanowire was obtained.

Then, using a PET film as the transparent substrate 104, the above coating material composition was applied to the surface of the transparent substrate 104 with a wire bar coater # 10, dried at 120 ° C. for 2 minutes, and then a UV integrated amount of 400 mJ / cm ^2. The transparent conductive film 105 having a film thickness of 0.2 μm was formed by irradiating with UV. In order to lower the drying temperature to 120 ° C. or lower, and further to 100 ° C. or lower, it is useful to increase the drying time to 2 minutes or longer.

  On the other hand, 20.0 parts by mass of a curable acrylic resin (“A-DPH” manufactured by Shin-Nakamura Chemical Co., Ltd.), 19.9 parts by mass of methyl ethyl ketone and 39.5 parts by weight of methyl isobutyl ketone were mixed to dissolve the acrylic resin. Mixture A was prepared. Also, black carbon nanoparticles (“Carbon Black # 2650” manufactured by Mitsubishi Chemical Co., Ltd .: average particle size 13 nm) were used as the light absorber, and 1.0 part by weight of this light absorber was dispersed in 20.0 parts by weight of methyl ethyl ketone. B was prepared. Then, after thoroughly mixing the mixture A and the mixture B, 0.1 parts by mass of a photopolymerization initiator (“Irgacure 184” manufactured by Ciba Geigy Co., Ltd.) is added and mixed well, and further stirred for 1 hour in a constant temperature atmosphere at 25 ° C. By mixing, the light absorption layer coating material composition which consists of a resin solution containing a light absorber was obtained.

Then, the light absorbing layer coating material composition is applied to the surface of the transparent conductive film 105 formed as described above with a wire bar coater # 6, dried at 120 ° C. for 2 minutes, and then UV is applied at a UV integrated amount of 400 mJ / cm ² . Was applied to form a light-absorbing layer 106 having a thickness of 0.1 μm, and a band-selective transparent shield 103 as Example 1 as shown in FIG. 2 and the like was obtained.

(Comparative Example 1)
Comparative Example 1 was obtained in the same manner as in Example 1, except that the transparent conductive film 105 was formed and the light absorption layer 106 was not formed.

  For the band-selective transparent shield obtained in Example 1 and Comparative Example 1, first, as optical evaluation, haze measurement, total light transmittance measurement, surface resistance value measurement, and surface smoothness measurement were performed. The haze and total light transmittance are measured using a haze meter (“NDH2000” manufactured by Nippon Denshoku Industries Co., Ltd.), and the surface resistance is measured by a surface resistance meter (“HirestaIP (MCP-HT260) manufactured by Mitsubishi Chemical Corporation). ) "). The surface smoothness was measured using a needle surface roughness meter (“SURFCOM 130A” manufactured by Tokyo Seimitsu Co., Ltd.). The results are shown in [Table 1].

  As shown in [Table 1], in Example 1, the light absorption layer was formed on the surface of the transparent conductive film, and thus the total light transmittance was reduced by about 0.6%. It was about 0.6 lower and the surface smoothness was improved, confirming the effect of the present invention. Moreover, the change of the surface resistance value by forming a light absorption layer was not seen. Further, the surface smoothness of Example 1 was also improved.

(Embodiment 8)
In the eighth embodiment, the results of investigation by the inventors on the further improvement of the characteristics based on the sample of [Table 1] will be shown. [Table 2] is a table showing an example of the results examined by the inventors, and is an example of a result of evaluating both the optical evaluation and the electromagnetic shielding effect. In [Table 2], both comparative products 1 and 2 were evaluated on a commercially available transparent film with ITO. As shown in comparative products 1 and 2, in the transparent film with ITO, it is difficult to increase the transmittance when the resistance is lowered, and problems such as cracks and curls occur as the resistance is lowered. As described above, since the transparent film with ITO has low curl resistance, a problem may occur in handleability.

  In [Table 2], Inventions 1 and 2 are Sample A (AgNW-No1, sheet resistance is 150Ω / □, Invention 1) prepared by the inventors shown in FIG. 5, Sample B (Ag-NW-) No. 2, sheet resistance is 40Ω / □, invention 2) is the result of measuring haze, total light transmittance, etc.

  From [Table 2], Invention 1 and Invention 2 had excellent shielding effects of having the band selectivity shown in FIG. 1 and FIG. Inventive product 1 and inventive product 2 both had an excellent shielding effect in the frequency band emitted from a liquid crystal panel or the like, and thus could exhibit an excellent TTP malfunction prevention function (TTP means transparent touch panel). . Inventive product 1 and inventive product 2 both have an excellent wireless LAN malfunction prevention function because the shielding effect (or attenuation factor) is reduced in the high frequency range represented by wireless LAN and the like.

  Thus, by using the inventive products 1 and 2, a high shielding effect and a low shielding effect can be obtained in each frequency band. Therefore, both the TTP malfunction comprehensive evaluation and the wireless LAN malfunction prevention can be performed with both (Good, Good).

  As described above, by using the inventive products 1 and 2, in the display device with a touch function such as A7 size to A4 size, further B4 size, newspaper size, etc., the display portion has high quality (for example, high definition, 2K). Even when 4K) is performed, malfunctions at the touch panel portion can be greatly reduced.

  On the other hand, as shown in comparative products 3 and 4, when the light absorption layer 106 is not provided on the metal nanowires (AgNW-No1, AgNW-No2), the haze value is increased and the image recognizability is affected. You can see that

  The results of [Table 2] will be further described. What used ITO for a transparent conductive film is the comparative product 1 and the comparative product 2, and the difference between the comparative product 1 and the comparative product 2 is the presence or absence of a light absorption layer. From the results of [Table 2], it was difficult to reduce the resistance of the transparent conductive film using ITO to 100Ω / □ or less, and further to 50Ω / □ or less. This is because the ITO film is colored (for example, yellow or metallic gloss) as the resistance of ITO is lowered.

  In addition, the various evaluation results in [Table 2] are results in consideration of the handleability of each sample. Here, handleability refers to the effect of bending during handling of samples during or after manufacture in addition to curling resistance.

  In the evaluation of [Table 2], the curl resistance refers to the curl when the sample is repeatedly bent (when the curl is positively generated) in addition to the evaluation of whether the sample itself is curled or not. It is evaluated whether or not a problem to be generated occurs. From the results of [Table 2], curl was likely to occur in the samples using ITO shown in comparative products 1 and 2. In addition, when the curled sample is subjected to physical curl correction, or when the non-curled sample is repeatedly rounded or straightened, fine cracks occur in the ITO film, resulting in sheet resistance. There was a case to change. On the other hand, in the comparative products 3 and 4 and the inventive products 1 and 2, no curling occurs. Even if the sample without the curling is repeatedly rolled or straightened, no crack or the like occurs and the sheet resistance is also reduced. It did not change.

  The evaluation of TTP operation stability and wireless LAN communication stability in [Table 2] is performed after evaluating the curl resistance of the prepared sheet with a transparent conductive film for evaluation that is repeatedly bent or stretched using a jig. This was done using a sample. As shown in [Table 2], in the comparison products 1 and 2, the TTP malfunction prevention function and the wireless LAN malfunction prevention function gave a (triggered) background. The ITO film generated in the evaluation of curl resistance The effects of cracks and the like can be considered. On the other hand, in the inventive products 1 and 2, excellent evaluation results of ○ (Good) were obtained in both TTP operation stability and wireless LAN communication stability. It is thought that it was resistant. From this background, it can be seen that the excellent band-selective shield characteristics of the band-selective transparent shields using Inventions 1 and 2 are not affected by the handling conditions during production or processing. As described above, the band-selective transparent shield using the products 1 and 2 of the present invention can be applied to the surface of the display device using a roll laminator or the like, or even when partially bent for incorporation into various display devices. It can be seen that its excellent shielding properties are not affected. Thus, in the case of invention products 1 and 2 which are one form of the band selective transparent shield of the present invention, a roll laminator or the like is provided on the surface of a display such as a liquid crystal or EL serving as a display device, or a capacitive transparent touch panel. Excellent TTP operation stability and excellent wireless LAN communication stability even when a part of the band-selective transparent shield is partially folded when it is pasted using a display or when incorporated in various display devices Is obtained. As described above, by using the band-selective transparent shield of the present invention, excellent TTP operation stability and excellent wireless LAN communication stability can be obtained even in a foldable display device and a flexible display device. Also, satisfying both excellent TTP operation stability and excellent wireless LAN communication stability at the same time by using the band-selective transparent shield of the present invention for general display devices and display devices that do not require flexibility. Needless to say, you can.

  On the other hand, in the case of a transparent shield using ITO (Comparative products 1 and 2), when pasted on the surface of a display device using a roll laminator, etc., or when partially folded when incorporated into various display devices, TTP operation Stability and wireless LAN communication stability may be reduced.

  According to the experiments by the inventors, the sheet resistance is appropriately 5Ω / □ or more and 200Ω / □ or less at least in the tablet size of the sample size of about smartphone size to A4 size. Therefore, in the case of a larger panel (for example, 1 tatami mat to 2 tatami mats), if the high performance of a smartphone or tablet terminal is not required, the sheet resistance range should be 2Ω / □ or more and 400Ω / □ or less. You can spread it.

  In addition, it is useful to adjust the color tone of the light absorption layer 106 in accordance with the display color tone of liquid crystal or EL. That is, when the color tone (or white balance) of the liquid crystal panel 109 (or EL panel) is shifted to the red side, the color tone of the light absorption layer 106 is cyan (or a complementary color, or a color positioned in the opposite direction in the hue circle, The white balance can be adjusted by setting the color tone such as extra color, contrast color, opposite color and hue.

  For example, when the ITO shown in the comparative product 1 shown in [Table 2] is used, the optical characteristics (transmission chromaticity) are L * = 93.01, a * = 0.31, b * = 3. It is found that the color difference defined by JIS Z 8729 becomes large and the problem of an increase in color difference due to the coloration of ITO itself occurs.

  On the other hand, as shown in [Table 2], the optical characteristics (transmission chromaticity) of Invention Product 1 (40Ω / □) are L * = 95.14, a * = − 0.36, b * = 0. 43. The optical properties (transmission chromaticity) of Invention Product 2 (150Ω / □) were L * = 95.48, a * = − 0.10, and b * = − 0.15. As described above, in the present invention, by adjusting the color tone and density of the light absorption layer 106 according to the liquid crystal panel or the light source for the liquid crystal panel, an excellent characteristic that the color difference defined in JIS Z 8729 can be suppressed is obtained. Have.

  Needless to say, the optical characteristics of the band selection transparent shield 103 can be further improved by adding a low bending layer, a high bending layer, or the like to the band selection transparent shield 103 as necessary.

  According to the present invention, it is possible to improve the performance of touch panels and the like as well as improving the quality of display portions such as portable terminals and small display pads (for example, high definition, 2K, and 4K).

DESCRIPTION OF SYMBOLS 101 Shield characteristic of invention product 102 Shield characteristic of conventional product 103 Band selection transparent shield 104 Transparent base material 105 Transparent conductive film 106 Light absorption layer 107 Metal nanowire 108a-108g Arrow 109 Liquid crystal panel 110 Touch panel 111 Display apparatus 112 Case 113 Internal antenna Part 114 External antenna part 115 Internal transmission / reception part 116 External transmission / reception part 117 Film with ITO 118 Crack 119 Display device 120 Adhesive layer

Claims (7)

A band-selective transparent shield comprising a transparent substrate, a transparent conductive film containing metal nanowires on the surface of the transparent substrate, and a light-absorbing layer having a pigment formed on the transparent conductive film. ,
Sheet resistance is 5Ω / □ or more and 200Ω / □ or less,
A band-selective transparent shield in which the attenuation rate S2 at a frequency (F2) 10 times higher than the frequency (Fsmax) indicating the maximum attenuation rate (Smax) is smaller in the range of 10 dB to 25 dB than the maximum attenuation rate (Smax). A band-selective transparent shield comprising a transparent substrate, a transparent conductive film containing metal nanowires on the surface of the transparent substrate, and a light-absorbing layer having a pigment formed on the transparent conductive film. ,
Sheet resistance is 5Ω / □ or more and 200Ω / □ or less,
The maximum attenuation rate (Smax) measured by the KEC method is in the range of 20 dB to 70 dB,
The frequency (Fsmax) indicating the maximum attenuation rate (Smax) measured by the KEC method is a band selective transparent shield that is in a band of 0.1 MHz to 30 MHz. A band-selective transparent shield comprising a transparent substrate, a transparent conductive film containing metal nanowires on the surface of the transparent substrate, and a light-absorbing layer having a pigment formed on the transparent conductive film. ,
The haze value measured from the light absorption layer side is smaller than the haze value measured from the transparent substrate side,
A band-selective transparent shield in which the attenuation factor decreases as the frequency increases within a frequency band of 20 dB to 70 dB in at least a frequency band of 10 MHz to 1000 MHz. The band-selective transparent shield according to any one of claims 1 to 3, wherein the light absorption layer further includes at least one of a different dye, carbon, or a conductive polymer. A preparation step of preparing a transparent substrate;
A transparent conductive film forming step of applying and forming a transparent conductive film containing metal nanowires on the surface on one or more surfaces of the transparent substrate;
A light absorption layer forming step of coating and forming a light absorption layer having a pigment on the transparent conductive film with a thickness of 0.5 μm to 300 μm,
The sheet resistance is 5Ω / □ or more and 200Ω / □ or less, and the attenuation rate S2 at a frequency (F2) 10 times higher than the frequency (Fsmax) indicating the maximum attenuation rate (Smax) is 10 dB or more and 25 dB above the maximum attenuation rate (Smax). A method for producing a band-selective transparent shield, characterized by being small in the following range. A display device having an image display panel unit or an electrostatic touch panel, and a band selection transparent shield,
The sheet resistance of the band-selective transparent shield is 5Ω / □ or more and 200Ω / □ or less,
A display device in which the attenuation rate S2 at a frequency (F2) 10 times higher than the frequency (Fsmax) indicating the maximum attenuation rate (Smax) is smaller in the range of 10 dB to 25 dB than the maximum attenuation rate (Smax). At least one of the housing and the antenna unit or the transceiver unit built in the housing,
An image display panel unit provided on one or more sides, a band selection transparent shield provided on the image display panel unit, and a capacitive touch panel unit provided on the band selection transparent shield A display device,
The sheet resistance of the band-selective transparent shield is 5Ω / □ or more and 200Ω / □ or less,
The attenuation rate S2 at a frequency (F2) that is ten times higher than the frequency (Fsmax) indicating the maximum attenuation rate (Smax) is a display device that is smaller in the range of 10 dB to 25 dB than the maximum attenuation rate (Smax).

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