JP5509186B2 - Touch panel and conductive sheet for touch panel - Google Patents

Description

  The present invention relates to a conductive sheet and a touch panel, for example, a conductive sheet and a touch panel used for a projected capacitive touch panel.

  As for the transparent conductive film using a thin metal wire, for example, as disclosed in Patent Documents 1 and 2, research continues.

  Recently, the touch panel has attracted attention. The touch panel is mainly applied to a small size such as a PDA (personal digital assistant) or a mobile phone, but it is considered that the touch panel will be increased in size by being applied to a display for a personal computer.

  In such a future trend, the conventional electrode uses ITO (indium tin oxide). ITO has a problem that the resistance increases and the transmission speed of the current between the electrodes decreases as the application size increases, and the response speed (the time from when the fingertip is touched until the position is detected) is delayed.

  Therefore, it is conceivable to reduce the surface resistance with an electrode formed of a thin metal wire. For example, Patent Documents 3 to 9 are known as touch panels using metal fine wires as electrodes.

US Patent Application Publication No. 2004/0229028 International Publication No. 2006/001461 Pamphlet JP-A-5-224818 US Pat. No. 5,130,041 International Publication No. 1995/27334 Pamphlet US Patent Application Publication No. 2004/0239650 US Pat. No. 7,202,859 International Publication No. 1997/18508 Pamphlet JP 2003-099185 A

  By the way, the sensing electrode of the touch panel includes an electrode pattern in which at least a touch region is formed of a thin metal wire, and an electrode terminal electrically connected to an end portion of the electrode pattern. The electrode terminal is a thick terminal (solid terminal) in order to have high conductivity. Therefore, when the display and the touch panel are operated in combination, in the sensing area (electrode pattern), since the electrode terminal blocks the light emitted from the display, a darkened portion appears in the vicinity of the electrode terminal in the sensing area, making it difficult to see the display. Sometimes.

  This invention is made | formed in view of such a subject, and it aims at providing the electrically conductive sheet and touch panel which do not impair visibility in the vicinity of the electrode terminal of a sensing area | region.

  The conductive sheet of the present invention is a conductive sheet having an electrode pattern composed of fine metal wires and electrode terminals electrically connected to the ends of the electrode patterns, and the electrode terminals are composed of fine metal wires. The mesh shape which consists of the lattice which was made is included.

  In the conductive sheet of the present invention, preferably, the electrode pattern has a mesh shape made of a lattice, and the mesh shape pitch made of the electrode terminal lattice is more than the mesh shape pitch made of the electrode pattern lattice. Is also dense. The mesh-shaped pitch formed of the electrode terminal lattice is more preferably 3/4 or less, further preferably 2/3 or less, and more preferably 1/2 of the mesh-shaped pitch formed of the electrode pattern lattice. The pitch of the mesh shape of a specific electrode terminal is 50 μm or more and 300 μm or less, and more preferably 50 μm or more and 250 μm or less.

  In the conductive sheet of the present invention, the electrode terminal is preferably provided with a mesh-shaped outer frame made of a lattice of the electrode terminals and a frame shape made of fine metal wires.

  The conductive sheet of the present invention preferably has a surface resistance value of the electrode terminal of 4 Ω / sq.

  The touch panel of the present invention includes an electrode pattern provided in a sensing area and configured by a thin metal wire, and an electrode terminal provided outside the sensing area and electrically connected to an end portion of the electrode pattern. In the touch panel having the conductive sheet, the electrode terminal includes a mesh shape made of a grid made of fine metal wires.

  According to the conductive sheet and the touch panel of the present invention, visibility can be prevented from being impaired in the vicinity of the electrode terminal in the sensing region.

The top view which shows an example of the electrode terminal of the electrically conductive sheet for touchscreens. The top view which shows another example of the electrode terminal of the electrically conductive sheet for touchscreens. The disassembled perspective view which abbreviate | omits and shows the electrically conductive sheet for touchscreens partially. FIG. 4A is a cross-sectional view showing an example of a conductive sheet for a touch panel with a part thereof omitted. FIG. 4B is a cross-sectional view illustrating another example of the conductive sheet for a touch panel with a part thereof omitted. FIG. 5A is a plan view showing an example of a first electrode pattern formed on the first conductive sheet. FIG. 5B is a plan view showing an example of a second electrode pattern formed on the second conductive sheet. The top view which abbreviate | omits and shows the example which made the conductive sheet for touchscreens combining the 1st conductive sheet and the 2nd conductive sheet.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The present invention will be described by the following preferred embodiments, but can be modified in many ways without departing from the scope of the present invention, and other embodiments than the present embodiment are utilized. be able to. Accordingly, all modifications within the scope of the present invention are included in the claims.

  Hereinafter, the conductive sheet and the touch panel according to the present embodiment will be described with reference to FIGS. In the present specification, “˜” indicating a numerical range is used as a meaning including numerical values described before and after the numerical value as a lower limit value and an upper limit value.

As shown in FIGS. 1 and 2, the conductive sheet 10 for a touch panel according to the present embodiment is electrically connected to an electrode pattern 16A (16B) composed of fine metal wires, and an end portion of the electrode pattern 16A (16B). and connected to the electrode terminals 60A (60B), an electrically electron over preparative 12A having (12B) and the electrode terminals 60A (60B) is to include a mesh shape 66 consisting of grating 68 made of a thin metal wire Configured.

  And the conductive sheet 10 for touchscreens concerning this Embodiment is comprised by laminating | stacking 1st conductive sheet 12A and 2nd conductive sheet 12B, as shown to FIG.3 and FIG.4 (a).

  As shown in FIGS. 3 and 5A, the first conductive sheet 12A has a first electrode pattern 16A formed on one main surface of the first transparent base 14A (see FIG. 4A). The first electrode pattern 16A is composed of a number of grids made of fine metal wires. Each of the first electrode patterns 16A extends in the first direction (x direction) and is arranged in a second direction (y direction) perpendicular to the first direction, and each of the two or more first conductive patterns 18A, A first non-conductive pattern 20A that electrically isolates the first conductive pattern 18A. In the first non-conductive pattern 20A, a plurality of disconnected portions 22A are formed in addition to the intersections of the fine metal wires. Each first conductive pattern 18A is electrically separated by the plurality of disconnected portions 22A.

  The fine metal wires constituting the first electrode pattern 16A have a line width of 30 μm or less, preferably 15 μm or less, more preferably 10 μm or less, further preferably 9 μm or less, and further preferably 7 μm or less. The first conductive pattern 18A and the first non-conductive pattern 20A have substantially the same line width, but in order to clarify the first conductive pattern 18A and the first non-conductive pattern 20A in FIG. The line width of the first conductive pattern 18A is widened and the line width of the first non-conductive pattern 20A is narrowed and exaggerated. The line width of the first conductive pattern 18A and the line width of the first non-conductive pattern 20A may be the same or different. Preferably, both line widths are the same. The reason is that the visibility may deteriorate if the line width is different. The fine metal wires of the first electrode pattern 16A are made of a metal material such as gold, silver, or copper, or a conductive material such as a metal oxide.

  The first electrode pattern 16A includes a plurality of grids 24A made up of intersecting fine metal wires. The lattice 24A includes an opening region surrounded by fine metal wires. The grating 24A has a grating pitch Pa of 300 μm to 800 μm, preferably 400 μm to 600 μm. The grid 24A of the first conductive pattern 18A and the grid 24A of the first non-conductive pattern 20A have substantially the same size.

  The grid 24A of the first non-conductive pattern 20A has a disconnected portion 22A in addition to the intersecting portion of the fine metal wires. It is not necessary for all the grids 24A constituting the first non-conductive pattern 20A to have the disconnection portions 22A. It is only necessary that the first non-conductive pattern 20A can achieve electrical separation between the adjacent first conductive patterns 18A. The length of the disconnection portion 22A is preferably 60 μm or less. The lower limit of the length of the disconnection portion 22A is preferably 10 μm, more preferably 15 μm, and even more preferably 20 μm. The upper limit value of the length of the disconnected portion 22A is preferably 50 μm, more preferably 40 μm, and even more preferably 30 μm. A preferable range is 10 μm or more and 50 μm or less, and 15 μm or more and 30 μm or less. Further, the range in which the disconnection portion 22A is formed can be expressed by, for example, variation in linear density. Here, the variation in the line density is the variation in the total fine line length in the unit small lattice, and can be defined as ± (total line length maximum value−total line length minimum value) / total line length average value / 2 (%). . The range in which the disconnection portion 22A is formed is preferably ± 15%, more preferably ± 10%, due to variations in cotton density.

  In the conductive sheet 10 for a touch panel described above, the grid 24A has a substantially rhombus shape. Here, the substantially rhombus shape means a parallelogram whose diagonal lines are substantially orthogonal. However, other polygonal shapes may be used. Further, the shape of one side may be a curved shape or a circular arc shape in addition to a linear shape. In the case of an arc shape, for example, two opposing sides may be outwardly convex arc shapes, and the other two opposing sides may be inwardly convex arc shapes. The shape of each side may be a wavy shape in which an outwardly convex arc and an inwardly convex arc are continuous. Of course, the shape of each side may be a sine curve.

  Each first conductive pattern 18A is a so-called diamond pattern having wide portions and narrow portions alternately arranged along the first direction (x direction). Similarly, each first non-conductive pattern 20A includes wide portions and narrow portions that are alternately arranged along the first direction (x direction). The order of the wide portion and the narrow portion of the first conductive pattern 18A is opposite to the order of the wide portion and the narrow portion of the first non-conductive pattern 20A. Each first conductive pattern 18A is not limited to the diamond pattern, but may be a strip shape having a predetermined width (stripe shape), a zigzag shape having a predetermined width, or the like. Examples of the patterning include an electrode shape applied with an existing ITO transparent conductive film.

  One end of each first conductive pattern 18A is electrically connected to the first external wiring 62A via the first electrode terminal 60A. On the other hand, the other end of each first conductive pattern 18A is an open end. The other end portion of each first conductive pattern 18A may have a pattern shape or a shape having a terminal similar to the one end portion, except that it is not electrically connected to the external wiring.

  As shown in FIGS. 3 and 5B, the second conductive sheet 12B has a second electrode pattern 16B formed on one main surface of the second transparent substrate 14B (see FIG. 4A). The second electrode pattern 16B is composed of a number of grids made of fine metal wires. Each of the second electrode patterns 16B extends in the second direction (y direction) and is arranged in a first direction (x direction) orthogonal to the second direction. A second non-conductive pattern 20B that electrically isolates the second conductive pattern 18B. In the second non-conductive pattern 20B, a plurality of disconnected portions 22B are formed in addition to the intersections of the fine metal wires. The second conductive patterns 18B are electrically separated by the plurality of disconnected portions 22B.

  The fine metal wires constituting the second electrode pattern 16B have substantially the same line width as the fine metal wires constituting the first electrode pattern 16A. Note that the second conductive pattern 18B and the second non-conductive pattern 20B have substantially the same line width, but in order to clarify the second conductive pattern 18B and the second non-conductive pattern 20B in FIG. 5B. The line width of the second conductive pattern 18B is increased and the line width of the second non-conductive pattern 20B is reduced and exaggerated. The line width of the second conductive pattern 18B and the line width of the second non-conductive pattern 20B may be the same or different. Preferably, both line widths are the same. The reason is that the visibility may deteriorate if the line width is different. The fine metal wires of the first electrode pattern 16A are made of a metal material such as gold, silver, or copper, or a conductive material such as a metal oxide. The fine metal wires of the first electrode pattern 16A are made of an opaque conductive material.

  The second electrode pattern 16B includes a plurality of grids 24B made up of intersecting fine metal wires. The lattice 24B includes an opening region surrounded by fine metal wires. The grating 24B has a grating pitch Pb of 300 μm or more and 800 μm or less, preferably 400 μm or more and 600 μm or less. The grid 24B of the second conductive pattern 18B and the grid 24B of the second non-conductive pattern 20B have substantially the same size.

  The grid 24B of the second non-conductive pattern 20B has a disconnected portion 22B in addition to the intersecting portion of the fine metal wires. It is not necessary for all the lattices 24B constituting the second non-conductive pattern 20B to have the disconnected portion 22B. It is only necessary that the second non-conductive pattern 20B can achieve electrical separation between the adjacent second conductive patterns 18B. The length of the disconnected portion 22B is preferably 60 μm or less. The lower limit of the length of the disconnection portion 22A is preferably 10 μm, more preferably 15 μm, and even more preferably 20 μm. The upper limit value of the length of the disconnected portion 22A is preferably 50 μm, more preferably 40 μm, and even more preferably 30 μm. A preferable range is 10 μm or more and 50 μm or less, and 15 μm or more and 30 μm or less. Further, the range in which the disconnection portion 22B is formed can be expressed by, for example, variation in linear density. Here, the variation in the line density is the variation in the total fine line length in the unit small lattice, and can be defined as ± (total line length maximum value−total line length minimum value) / total line length average value / 2 (%). . The range in which the disconnection portion 22B is formed is preferably ± 15%, more preferably ± 10%, due to variations in cotton density.

  In the touch panel conductive sheet 10 described above, the lattice 24B has a substantially rhombus shape. Here, the substantially rhombus shape means a parallelogram whose diagonal lines are substantially orthogonal. However, other polygonal shapes may be used. Further, the shape of one side may be a curved shape or a circular arc shape in addition to a linear shape. In the case of an arc shape, for example, two opposing sides may be outwardly convex arc shapes, and the other two opposing sides may be inwardly convex arc shapes. The shape of each side may be a wavy shape in which an outwardly convex arc and an inwardly convex arc are continuous. Of course, the shape of each side may be a sine curve.

  Each of the second conductive patterns 18B includes wide portions and narrow portions that are alternately arranged along the second direction (y direction). Similarly, each second non-conductive pattern 20B includes wide portions and narrow portions that are alternately arranged along the second direction (y direction). The order of the wide portion and the narrow portion of the second conductive pattern 18B is opposite to the order of the wide portion and the narrow portion of the second non-conductive pattern 20B.

  One end of each second conductive pattern 18B is electrically connected to the second external wiring 62B via the second electrode terminal 60B. On the other hand, the other end of each second conductive pattern 18B is an open end.

  For example, when the first conductive sheet 12A is laminated on the second conductive sheet 12B to form the touch panel conductive sheet 10, the first electrode pattern 16A and the second electrode pattern 16B overlap as shown in FIG. Not arranged. At this time, the narrow portion of the first conductive pattern 18A and the narrow portion of the second conductive pattern 18B face each other, and the narrow portion of the first conductive pattern 18A and the second conductive pattern 18B intersect. The first electrode pattern 16A and the second electrode pattern 16B are disposed. As a result, the combination pattern 70 is formed by the first electrode pattern 16A and the second electrode pattern 16B. Note that the line widths of the first electrode pattern 16A and the second electrode pattern 16B are substantially the same. In addition, the sizes of the lattice 24A and the lattice 24B are substantially the same. However, in FIG. 6, in order to clarify the positional relationship between the first electrode pattern 16A and the second electrode pattern 16B, the line width of the first electrode pattern 16A is displayed wider than the line width of the second electrode pattern 16B. .

In combination pattern 70, in a top view, the small lattice is formed by the grating 24A and the grating 24B. That is, the intersection of the grating 24A is arranged in the opening area of the grating 24B. Incidentally, the small lattice, the lattice pitch Pa of the grating 24A and the grating 24B, less than half of 150μm or 400μm of Pb, preferably a 300μm following the grating pitch Ps than 200 [mu] m.

  The disconnected portion 22A of the first non-conductive pattern 20A is formed at a portion other than the intersection of the lattice 24A, and the disconnected portion 22B of the second non-conductive pattern 20B is formed at a portion other than the intersection of the lattice 24B. As a result, in the combination pattern 70, it is possible to prevent the deterioration of visibility due to the disconnection portion 22A and the disconnection portion 22B.

  In particular, the fine metal wire of the second conductive pattern 18B is disposed at a position facing the disconnection portion 22A. In addition, a fine metal wire of the first conductive pattern 18A is disposed at a position facing the disconnection portion 22B. The fine metal wire of the second conductive pattern 18B masks the disconnection portion 22A, and the fine metal wire of the first conductive pattern 18A masks the disconnection portion 22B. Therefore, in the combination pattern 70, the disconnection portion 22A and the disconnection portion 22B are hardly visually recognized in a top view, and thus visibility can be improved. Considering the improvement in visibility, it is preferable that the length of the disconnected portion 22A and the line width of the thin metal wire of the second conductive pattern 18B satisfy the relational expression of line width × 1 <disconnected portion <line width × 10. Similarly, it is preferable that the length of the disconnection portion 22B and the line width of the thin metal wire of the first conductive pattern 18A satisfy the relational expression of line width × 1 <disconnection portion <line width × 10.

  And when using this conductive sheet 10 for touch panels as a touch panel, a protective layer (not shown) is formed on the first conductive sheet 12A. The first external wiring 62A derived from a large number of first conductive patterns 18A of the first conductive sheet 12A and the second external wiring 62B derived from a large number of second conductive patterns 18B of the second conductive sheet 12B include, for example, It is connected to an IC circuit that controls scanning.

  In the conductive sheet 10 for the touch panel, each connection portion between the first conductive pattern 18A and the first external wiring 62A is preferably linear so that the area of the outer peripheral region that is removed from the display screen of the liquid crystal display device is minimized. The connecting portions between the second conductive pattern 18B and the second external wiring 62B are arranged in a straight line.

  By bringing the fingertip into contact with the protective layer, the capacitance between the first conductive pattern 18A and the second conductive pattern 18B facing the fingertip changes. The IC circuit detects the amount of change and calculates the position of the fingertip based on the amount of change. This calculation is performed between the first conductive pattern 18A and the second conductive pattern 18B. Therefore, it is possible to detect the position of each fingertip even if two or more fingertips are brought into contact with each other at the same time.

  Thus, in the conductive sheet 10 for a touch panel, when the conductive sheet 10 for a touch panel is applied to, for example, a projected capacitive touch panel, the response speed can be increased because the surface resistance is small. The touch panel can be increased in size.

  However, in the touch panel using a conventional thin metal wire as the electrode, the electrode terminals 60A and 60B are thick terminals (solid terminals) because they have high conductivity. In the sensing region (electrode pattern), since the electrode terminal blocks the light emitted from the display, a darkened portion appears in the vicinity of the electrode terminal in the sensing region, and the display at that portion may be difficult to see.

  Accordingly, in the present invention, the base 14A is provided with an electrode pattern 16A (16B) composed of a fine metal wire and an electrode terminal 60A (60B) electrically connected to the end of the electrode pattern 16A (16B). In the conductive sheet 12A (12B), the electrode terminal 60A (60B) includes a mesh shape 66 composed of a lattice 68 made of fine metal wires.

  FIG. 1 shows that the electrode terminal 60A (60B) has a mesh shape 66 composed of a lattice 68 made of fine metal wires.

  Here, the pitch of the mesh shape 66 of the electrode terminal 60A (60B) is preferably denser than the pitch of the electrode pattern 16A (16B), more preferably 3/4 or less of the pitch of the electrode pattern 16A (16B). 2/3 or less is more preferable, and 1/2 is more preferable. By making the pitch of the mesh shape of the electrode terminals smaller than the electrode pattern, the electrical characteristics of the electrode terminals can be improved, and the stability of signal detection can be maintained. The pitch of the mesh shape 66 of the specific electrode terminal 60A (60B) is 50 μm or more and 300 μm or less, and more preferably 50 μm or more and 250 μm or less. Note that the pitch of the electrode patterns 16A (16B) is substantially equal to the length of one side of the lattice 24A (24B).

As shown in FIG. 1, the electrode terminal 60A (60B) is changed to a mesh shape 66 made of a lattice 68 in which the electrode terminal 60A (60B) is made of a thin metal wire, thereby making the touch panel different from a conventional thick terminal (solid terminal) In the sensing region (electrode pattern), since the electrode terminal is difficult to block the light emitted from the display, a darkened portion does not appear near the electrode terminal in the sensing region. Therefore, the visibility is not impaired near the electrode terminals in the sensing region.

  FIG. 2 shows that the electrode terminal 60A (60B) in FIG. 1 has a mesh shape 66 made of a grid 68 made of fine metal wires, an outer frame of the mesh shape 66 made of a grid 68 of electrode terminals, and a metal A frame shape 64 composed of thin lines is provided. That is, the electrode terminal 60A (60B) is shown to have a frame shape 64 made of fine metal wires and a mesh shape 66 made of a lattice 68 made of fine metal wires.

  Here, when the line width of the thin line of the electrode pattern 16A (16B) is A (μm), the line width B (μm) of the frame shape 64 of the electrode terminal 60A (60B) is B ≧ 2A or B ≧ It is preferable to satisfy A + 5 (μm).

  As shown in FIG. 2, the electrode terminal 60A (60B) is composed of a frame shape 64 made up of fine metal wires and a mesh shape 66 made up of a grid 68 made up of fine metal wires. Unlike the terminal), in the sensing region (electrode pattern) of the touch panel, it is possible to prevent light from being diffusely reflected by the electrode terminal, and thus it is possible to prevent a dark portion from appearing in the vicinity of the electrode terminal in the sensing region.

  In the mesh shape 66 of FIGS. 1 and 2, the lattice 68 has a substantially rhombus shape. Here, the substantially rhombus shape means a parallelogram whose diagonal lines are substantially orthogonal.

  In the electrode terminal 60A (60B) according to the present invention, the resistance between the portion electrically connected to the electrode pattern and the external wiring 62A (62B) is preferably in the range of 1 to 100Ω. In addition, in the electrode terminal 60A (60B) as shown in FIGS. 1 and 2, the surface resistance value of the electrode terminal 60A (60B) is preferably in the range of 4Ω / sq. To 80Ω / sq. More preferably, it is in the range of 40Ω / sq.

  In the present invention, when the transmittance of the electrode pattern 16A (16B) is 83% or more and the transmittance of the electrode pattern 16A (16B) is expressed as a%, the transmittance of the electrode terminal 60A (60B) is ( It is preferable that they are a-20)% or more and (a-3)% or less.

  Furthermore, in the present invention, when the aperture ratio of the electrode pattern 16A (16B) is 90% or more and the aperture ratio of the electrode pattern 16A (16B) is expressed as b%, the aperture ratio of the electrode terminal 60A (60B) is It is preferable that it is (b-20)% or more and (b-0.1)% or less. Here, the aperture ratio is the ratio of the translucent portion of the electrode terminal 60A (60B) excluding the thin metal wires to the whole. For example, the aperture ratio of the square lattice 68 having a line width of 15 μm and a pitch of 300 μm is 90%.

  As described above, according to the present invention, it is possible to prevent a darkened portion from appearing in the vicinity of the electrode terminal in the sensing region. However, as another effect, the conductive sheet 12A (12B) is manufactured by a method by exposure described below. In this case, there is an effect that it is possible to prevent the metal thin wire near the electrode terminal in the sensing region from becoming thicker than the intended line width.

  Since the conventional electrode terminal is a thick terminal (solid terminal) in order to have high conductivity, a large amount of light is irradiated to the portion that becomes the electrode terminal by exposure. There is a problem that the line width of the electrode pattern is very small and is transmitted to the portion that becomes the electrode pattern in the vicinity of the electrode terminal, and the fine metal wire in the vicinity of the electrode terminal becomes thicker than the intended line width.

  That is, by setting the transmittance or aperture ratio of the electrode terminal 60A (60B) as in the present invention, a portion that becomes the electrode terminal by exposure is not irradiated with a large amount of light, and in the vicinity of the electrode terminal in the sensing region. It is possible to prevent the metal fine wire from becoming thicker than the intended line width.

  When the touch panel using the conductive sheet according to the present invention is operated by touching with a finger, the response speed is fast and the detection sensitivity is excellent. In addition, even if two or more points are touched and operated, good results can be obtained in the same manner, and multi-touch can be handled.

  Next, a method for manufacturing the first conductive sheet 12A and the second conductive sheet 12B will be described.

  When manufacturing the first conductive sheet 12A and the second conductive sheet 12B, for example, a photosensitive material having an emulsion layer containing a photosensitive silver halide salt on the first transparent substrate 14A and the second transparent substrate 14B is exposed. By performing the development process, the first electrode pattern 16A and the second electrode pattern 16B are formed by forming a metal silver portion (metal fine line) and a light transmissive portion (opening region) in the exposed portion and the unexposed portion, respectively. You may do it. In addition, you may make it carry | support a conductive metal to a metal silver part by giving a physical development and / or a plating process to a metal silver part further.

  Alternatively, the photoresist film on the copper foil formed on the first transparent substrate 14A and the second transparent substrate 14B is exposed and developed to form a resist pattern, and the copper foil exposed from the resist pattern is etched. The first electrode pattern 16A and the second electrode pattern 16B may be formed.

  Alternatively, the first electrode pattern 16A and the second electrode pattern 16B are formed by printing a paste containing metal fine particles on the first transparent substrate 14A and the second transparent substrate 14B and performing metal plating on the paste. Also good.

  When the first electrode pattern 16A and the second electrode pattern 16B are formed by the above-described two exposure methods, the present invention prevents the metal thin wire near the electrode terminal in the sensing region from becoming thicker than the intended line width. There is also an effect of being able to.

  The first electrode pattern 16A and the second electrode pattern 16B may be printed and formed on the first transparent substrate 14A and the second transparent substrate 14B by a screen printing plate or a gravure printing plate. Alternatively, the first electrode pattern 16A and the second electrode pattern 16B may be formed by inkjet on the first transparent substrate 14A and the second transparent substrate 14B.

  When the first electrode pattern 16A is formed on one main surface of the first transparent base 14A and the second electrode pattern 16B is formed on the other main surface of the first transparent base 14A, as shown in FIG. In accordance with the manufacturing method, if the method of exposing one principal surface first and then exposing the other principal surface is adopted, the first electrode pattern 16A and the second electrode pattern 16B having a desired pattern cannot be obtained. There is a case.

  Therefore, the following manufacturing method can be preferably employed.

  That is, the photosensitive silver halide emulsion layer formed on both surfaces of the first transparent substrate 14A is collectively exposed to form the first electrode pattern 16A on one main surface of the first transparent substrate 14A. A second electrode pattern 16B is formed on the other main surface of the transparent substrate 14A.

  A specific example of this manufacturing method will be described.

  First, a long photosensitive material is prepared. The photosensitive material includes a first transparent substrate 14A, a photosensitive silver halide emulsion layer (hereinafter referred to as a first photosensitive layer) formed on one main surface of the first transparent substrate 14A, and the other of the first transparent substrate 14A. A light-sensitive silver halide emulsion layer (hereinafter referred to as a second photosensitive layer) formed on the main surface.

  Next, the photosensitive material is exposed. In this exposure process, the first photosensitive layer is irradiated with light toward the first transparent substrate 14A to expose the first photosensitive layer along the first exposure pattern, and the second photosensitive layer is exposed. On the other hand, a second exposure process is performed in which light is irradiated toward the first transparent substrate 14A to expose the second photosensitive layer along the second exposure pattern (double-sided simultaneous exposure).

  For example, while conveying a long photosensitive material in one direction, the first photosensitive layer is irradiated with the first light (parallel light) through the first photomask, and the second photosensitive layer is irradiated with the second light (parallel light). ) Through the second photomask. The first light is obtained by converting the light emitted from the first light source into parallel light by the first collimator lens in the middle, and the second light is obtained by converting the light emitted from the second light source in the middle of the first light. It is obtained by being converted into parallel light by a two-collimator lens.

  In the above description, the case where two light sources (the first light source and the second light source) are used is shown, but the light emitted from one light source is divided through the optical system, and the first light and the second light are divided. The first photosensitive layer and the second photosensitive layer may be irradiated as light.

  Next, the exposed photosensitive material is developed to produce a conductive sheet 10 for a touch panel, for example, as shown in FIG. 4B. The touch panel conductive sheet 10 includes a first transparent substrate 14A, a first electrode pattern 16A along a first exposure pattern formed on one main surface of the first transparent substrate 14A, and the other of the first transparent substrate 14A. And a second electrode pattern 16B along the second exposure pattern formed on the main surface. In addition, since the exposure time and development time of the first photosensitive layer and the second photosensitive layer vary depending on the types of the first light source and the second light source, the type of the developer, and the like, the preferable numerical range should be determined unambiguously. However, the exposure time and the development time are adjusted so that the development rate becomes 100%.

  In the manufacturing method according to the present embodiment, the first exposure process includes, for example, arranging a first photomask on the first photosensitive layer in close contact with the first light source arranged opposite to the first photomask. The first photosensitive layer is exposed by irradiating the first light toward one photomask. The first photomask is composed of a glass substrate formed of transparent soda glass and a mask pattern (first exposure pattern) formed on the glass substrate. Accordingly, the first exposure process exposes a portion of the first photosensitive layer along the first exposure pattern formed on the first photomask. A gap of about 2 μm or more and 10 μm or less may be provided between the first photosensitive layer and the first photomask 146a.

  Similarly, in the second exposure process, for example, a second photomask is disposed in close contact with the second photosensitive layer, and the second light source disposed opposite to the second photomask is secondly directed toward the second photomask. The second photosensitive layer is exposed by irradiating light. Similar to the first photomask, the second photomask is composed of a glass substrate made of transparent soda glass and a mask pattern (second exposure pattern) formed on the glass substrate. Therefore, the second exposure process exposes a portion of the second photosensitive layer along the second exposure pattern formed on the second photomask. In this case, a gap of about 2 μm or more and 10 μm or less may be provided between the second photosensitive layer and the second photomask.

  In the first exposure process and the second exposure process, the emission timing of the first light from the first light source and the emission timing of the second light from the second light source may be performed simultaneously or differently. At the same time, the first photosensitive layer and the second photosensitive layer can be exposed simultaneously by one exposure process, and the processing time can be shortened.

  Next, in the first conductive sheet 12A and the second conductive sheet 12B according to the present embodiment, a method using a silver halide photographic light-sensitive material that is a particularly preferable aspect will be mainly described.

  The manufacturing method of the first conductive sheet 12A and the second conductive sheet 12B according to the present embodiment includes the following three modes depending on the mode of the photosensitive material and the development process.

  (1) A mode in which a photosensitive silver halide black-and-white photosensitive material not containing physical development nuclei is chemically developed or thermally developed to form a metallic silver portion on the photosensitive material.

  (2) An embodiment in which a photosensitive silver halide black-and-white photosensitive material containing physical development nuclei in a silver halide emulsion layer is dissolved and physically developed to form a metallic silver portion on the photosensitive material.

  (3) A photosensitive silver halide black-and-white photosensitive material containing no physical development nuclei and an image receiving sheet having a non-photosensitive layer containing physical development nuclei are overlapped and developed by diffusion transfer, and the metallic silver portion is non-photosensitive image-receiving sheet. Form formed on top.

  The aspect (1) is an integrated black-and-white development type, and a light-transmitting conductive film such as a light-transmitting conductive film is formed on the photosensitive material. The obtained developed silver is chemically developed silver or heat developed silver, and is highly active in the subsequent plating or physical development process in that it is a filament with a high specific surface.

  In the above aspect (2), the light-transmitting conductive film such as a light-transmitting conductive film is formed on the photosensitive material by dissolving silver halide grains close to the physical development nucleus and depositing on the development nucleus in the exposed portion. A characteristic film is formed. This is also an integrated black-and-white development type. Although the development action is precipitation on the physical development nuclei, it is highly active, but developed silver is a sphere with a small specific surface.

  In the above aspect (3), the silver halide grains are dissolved and diffused in the unexposed area and deposited on the development nuclei on the image receiving sheet, whereby a light transmitting conductive film or the like is formed on the image receiving sheet. A conductive film is formed. This is a so-called separate type in which the image receiving sheet is peeled off from the photosensitive material.

  In either embodiment, either negative development processing or reversal development processing can be selected (in the case of the diffusion transfer method, negative development processing is possible by using an auto-positive type photosensitive material as the photosensitive material). .

Here, the configuration of each layer of the first conductive sheet 12A and the second conductive sheet 12B according to the present embodiment will be described in detail below.

[First Transparent Base 14A, Second Transparent Base 14B]
Examples of the first transparent substrate 14A and the second transparent substrate 14B include a plastic film, a plastic plate, and a glass plate. In particular, PET is preferable from the viewpoints of light transmittance and processability.

[Silver salt emulsion layer]
The silver salt emulsion layer that becomes the first electrode pattern 16A of the first conductive sheet 12A and the second electrode pattern 16B of the second conductive sheet 12B contains additives such as a solvent and a dye in addition to the silver salt and the binder.

  Examples of the silver salt used in the present embodiment include inorganic silver salts such as silver halide and organic silver salts such as silver acetate. In the present embodiment, it is preferable to use silver halide having excellent characteristics as an optical sensor.

Silver coating amount of silver salt emulsion layer (silver salt coating amount) is preferably from 1 g / ^{m 2} or more 30 g / ^{m 2} or less in terms of silver, 1 g / ^m, more preferably ² or more 25 g / ^{m 2} or less, 5g / M ² or more and 20 g / m ² or less is more preferable. By setting the amount of coated silver in the above range, a desired surface resistance can be obtained when the conductive sheet 10 for a touch panel is used.

Examples of the binder used in this embodiment include gelatin, polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), starch and other polysaccharides, cellulose and derivatives thereof, polyethylene oxide, polyvinyl amine, chitosan, polylysine, and polyacryl. Examples include acid, polyalginic acid, polyhyaluronic acid, carboxycellulose and the like.
These have neutral, anionic, and cationic properties depending on the ionicity of the functional group.

  The content of the binder contained in the silver salt emulsion layer of the present embodiment is not particularly limited, and can be appropriately determined as long as dispersibility and adhesion can be exhibited. The binder content in the silver salt emulsion layer is preferably ¼ or more, more preferably ½ or more in terms of the silver / binder volume ratio. The silver / binder volume ratio is preferably 100/1 or less, and more preferably 50/1 or less. Further, the silver / binder volume ratio is more preferably 1/1 or more and 4/1 or less. Most preferably, it is 1/1 to 3/1. By setting the silver / binder volume ratio in the silver salt emulsion layer within this range, even when the amount of coated silver is adjusted, variation in resistance value can be suppressed, and a conductive sheet for touch panel having uniform surface resistance can be obtained. . The silver / binder volume ratio is converted from the amount of silver halide / binder amount (weight ratio) of the raw material to the amount of silver / binder amount (weight ratio), and the amount of silver / binder amount (weight ratio) is further converted to the silver amount. / It can obtain | require by converting into binder amount (volume ratio).

<Solvent>
The solvent used for forming the silver salt emulsion layer is not particularly limited. For example, water, organic solvents (for example, alcohols such as methanol, ketones such as acetone, amides such as formamide, dimethyl sulfoxide, etc. Sulphoxides such as, esters such as ethyl acetate, ethers, etc.), ionic liquids, and mixed solvents thereof.

  The content of the solvent used in the silver salt emulsion layer of the present embodiment is in the range of 30 to 90% by mass with respect to the total mass of the silver salt and binder contained in the silver salt emulsion layer, and 50 to 80 It is preferably in the range of mass%.

<Other additives>
The various additives used in the present embodiment are not particularly limited, and known ones can be preferably used.

[Other layer structure]
A protective layer (not shown) may be provided on the silver salt emulsion layer. In the present embodiment, the “protective layer” means a layer made of a binder such as gelatin or a high molecular polymer, and is formed on a silver salt emulsion layer having photosensitivity in order to exhibit an effect of preventing scratches and improving mechanical properties. It is formed. The thickness is preferably 0.5 μm or less. The coating method and forming method of the protective layer are not particularly limited, and a known coating method and forming method can be appropriately selected. An undercoat layer, for example, can be provided below the silver salt emulsion layer.

  Next, each step of the manufacturing method of the first conductive sheet 12A and the second conductive sheet 12B will be described.

[exposure]
This embodiment includes the case where the first electrode pattern 16A and the second electrode pattern 16B are applied by a printing method, but the first electrode pattern 16A and the second electrode pattern 16B are formed by exposure and development, etc., except for the printing method. To do. That is, exposure is performed on a photosensitive material having a silver salt-containing layer provided on the first transparent substrate 14A and the second transparent substrate 14B or a photosensitive material coated with a photolithography photopolymer. The exposure can be performed using electromagnetic waves. Examples of the electromagnetic wave include light such as visible light and ultraviolet light, and radiation such as X-rays.
Furthermore, a light source having a wavelength distribution may be used for exposure, or a light source having a specific wavelength may be used.

  Regarding the exposure method, a method through a glass mask or a pattern exposure method by laser drawing is preferable.

[Development processing]
In this embodiment, after the emulsion layer is exposed, development processing is further performed. The development processing can be performed by a normal development processing technique used for silver salt photographic film, photographic paper, printing plate-making film, photomask emulsion mask, and the like.

  The development process in the present embodiment can include a fixing process performed for the purpose of removing and stabilizing the silver salt in the unexposed part. For the fixing process in the present invention, a fixing process technique used for silver salt photographic film, photographic paper, film for printing plate making, emulsion mask for photomask, and the like can be used.

  The light-sensitive material that has undergone development and fixing is preferably subjected to a film hardening process, a water washing process, and a stabilization process.

  The mass of the metallic silver contained in the exposed portion after the development treatment is preferably a content of 50% by mass or more, and 80% by mass or more with respect to the mass of silver contained in the exposed portion before exposure. More preferably. If the mass of silver contained in the exposed portion is 50% by mass or more based on the mass of silver contained in the exposed portion before exposure, it is preferable because high conductivity can be obtained.

  Although the conductive sheet is obtained through the above steps, the surface resistance of the obtained conductive sheet is 100 ohm / sq. The following is preferable, and 80 ohm / sq. The following is more preferable, and 60 ohm / sq. The following is more preferable, and 40 ohm / sq. The following is even more preferable. The lower limit of the surface resistance is preferably as low as possible, but is generally 0.01 ohm / sq. Is sufficient, 0.1 ohm / sq. And 1 ohm / sq. However, it can be used depending on the application.

  By adjusting the surface resistance within such a range, position detection can be performed even with a large touch panel having an area of 10 cm × 10 cm or more. Further, the conductive sheet after the development process may be further subjected to a conductivity improving process such as a calendar process or a steam process, and the desired surface resistance can be adjusted by the calendar process.

[Physical development and plating]
In the present embodiment, for the purpose of improving the conductivity of the metallic silver portion formed by the exposure and development processing, physical development and / or plating treatment for supporting the conductive metal particles on the metallic silver portion is performed. May be. In the present invention, the conductive metal particles may be supported on the metallic silver portion by only one of physical development and plating treatment, or the conductive metal particles are supported on the metallic silver portion by combining physical development and plating treatment. May be. In addition, the thing which performed the physical development and / or the plating process to the metal silver part is called "conductive metal part".

[Oxidation treatment]
In the present embodiment, it is preferable to subject the metallic silver portion after the development treatment and the conductive metal portion formed by physical development and / or plating treatment to oxidation treatment. By performing the oxidation treatment, for example, when a metal is slightly deposited on the light transmissive portion, the metal can be removed and the light transmissive portion can be made almost 100% transparent.

[Electrode pattern]
The line width of the fine metal wires of the first electrode pattern 16A and the second electrode pattern 16B of the present embodiment can be selected from 30 μm or less. However, in the case of use as a touch panel material, the lower limit of the thin metal wire width The value is preferably 0.7 μm, more preferably 1 μm, still more preferably 2 μm. The upper limit of the line width of the fine metal wire is preferably 15 μm, more preferably 9 μm, and even more preferably 7 μm.

  A conventional electrode terminal is a thick terminal (solid terminal) in order to have high conductivity, and a large amount of light is irradiated to a portion that becomes an electrode terminal by exposure. The line width of the electrode pattern is very small as described above, and may be affected by the large amount of light. In particular, when the line width is 9 μm or less, further 7 μm or less, the influence becomes remarkable, and there is a problem that the metal thin wire near the electrode terminal becomes thicker than the intended line width.

  The line spacing (lattice pitch) is preferably 100 μm or more and 400 μm or less, and more preferably 200 μm or more and 300 μm or less. Further, the thin metal wire may have a portion wider than 200 μm for the purpose of ground connection or the like.

[Light transmissive part]
The “light transmissive part” in the present embodiment means a part having translucency other than the first electrode pattern 16A and the second electrode pattern 16B in the first conductive sheet 12A and the second conductive sheet 12B. As described above, the transmittance in the light transmissive portion is the transmission indicated by the minimum value of the transmittance in the wavelength region of 380 to 780 nm excluding contributions of light absorption and reflection of the first transparent substrate 14A and the second transparent substrate 14B. The rate is 83% or more, preferably 85% or more, more preferably 90% or more, still more preferably 93% or more, and most preferably 99% or more.

[First conductive sheet 12A and second conductive sheet 12B]
The thickness of the first transparent substrate 14A and the second transparent substrate 14B in the first conductive sheet 12A and the second conductive sheet 12B according to the present embodiment is preferably 5 μm or more and 350 μm or less, and is 30 μm or more and 150 μm or less. More preferably. If it is in the range of 5 μm or more and 350 μm or less, a desired visible light transmittance can be obtained and handling is easy.

  The thickness of the metallic silver portion provided on the first transparent substrate 14A and the second transparent substrate 14B depends on the coating thickness of the silver salt-containing layer coating applied on the first transparent substrate 14A and the second transparent substrate 14B. Can be determined as appropriate. The thickness of the metallic silver portion can be selected from 0.001 mm to 0.2 mm, preferably 30 μm or less, more preferably 20 μm or less, and 0.01 μm to 9 μm. More preferably, it is 0.05 μm or more and 5 μm or less. Moreover, it is preferable that a metal silver part is pattern shape. The metallic silver part may be a single layer or a multilayer structure of two or more layers. When the metallic silver portion is patterned and has a multilayer structure of two or more layers, different color sensitivities can be imparted so as to be sensitive to different wavelengths. Thereby, when the exposure wavelength is changed and exposed, a different pattern can be formed in each layer.

  As the thickness of the conductive metal part, the thinner the display panel, the wider the viewing angle of the display panel, and the thinner the display is required for improving the visibility. From such a viewpoint, the thickness of the layer made of the conductive metal carried on the conductive metal part is preferably less than 9 μm, more preferably 0.1 μm or more and less than 5 μm, and more preferably 0.1 μm or more. More preferably, it is less than 3 μm.

  In the present embodiment, the thickness of the layer made of conductive metal particles is formed by controlling the coating thickness of the silver salt-containing layer described above to form a metallic silver portion having a desired thickness, and further by physical development and / or plating treatment. Therefore, even the first conductive sheet 12A and the second conductive sheet 12B having a thickness of less than 5 μm, preferably less than 3 μm can be easily formed.

  Of course, the conductive sheet and the touch panel according to the present invention are not limited to the above-described embodiments, and can adopt various configurations without departing from the gist of the present invention. Further, it can be used in appropriate combination with the techniques disclosed in JP2011-113149, JP2011-129501, JP2011-129112, JP2011-134311, JP2011-175628, and the like.

  10 (for touch panel), 12A (first) conductive sheet, 12B (second) conductive sheet, 14A (first) transparent substrate, 14B (second) transparent substrate, 16A (first) ) Electrode pattern, 16B (second) electrode pattern, 18A ... (first) conductive pattern, 18B ... (second) conductive pattern, 20A ... (first) non-conductive pattern, 20B ... (second) non-conductive pattern 22A ... disconnected portion, 22B ... disconnected portion, 24A ... lattice, 24B ... lattice, 60A ... (first) electrode terminal, 60B ... (second) electrode terminal, 62A ... (first) external wiring, 62B ... (first 2) External wiring, 64 ... frame shape, 66 ... mesh shape, 68 ... lattice, 70 ... combination pattern

Claims (16)

An electrode pattern formed of a thin metal wire having a line width of 0.7 to 9 μm provided in the sensing region, and an electrode terminal provided outside the sensing region and electrically connected to an end of the electrode pattern; , A touch panel having a conductive sheet provided with,
The electrode terminal is a touch panel including a mesh shape made of a lattice made of fine metal wires. The touch panel according to claim 1, wherein a line width of a thin metal wire constituting the electrode pattern is 1 to 7 μm . The electrode pattern, together with a mesh shape made of the grating, the pitch of the mesh shape composed of grid electrode terminal, the electrode dense than the pitch of the mesh shape made of lattice is claim 1 or claim pattern 2 Touch panel as described in 1. The touch panel according to claim 3 , wherein a pitch of the mesh shape made of the grid of the electrode terminals is 3/4 or less of a pitch of the mesh shape made of the grid of the electrode pattern. The touch panel according to claim 3, wherein a pitch of the mesh shape formed of the grid of the electrode terminals is 2/3 or less of a pitch of the mesh shape formed of the grid of the electrode pattern. The touch panel according to claim 3, wherein a pitch of the mesh shape formed of the grid of the electrode terminals is ½ or less of a pitch of the mesh shape formed of the grid of the electrode pattern. The touch panel according to any one of claims 1 to 6, wherein the other end portion to which the electrode terminal is not connected is an open end with respect to the end portion of the electrode pattern. 7. The device according to claim 1, further comprising an additional electrode terminal at the other end where the electrode terminal is not connected to the end of the electrode pattern, wherein the additional electrode terminal has a mesh shape made of a lattice. The touch panel according to claim 1. The pitch of the mesh shape composed of grid electrode terminal includes a touch panel according to any one of claims 3 to 8 is 50μm or more 300μm or less. Wherein the electrode terminal, the outer frame of the mesh shape made from the lattice of the electrode terminal, further, the touch panel according to any one of claims 1 to 9, frame shape made of a thin metal wire is provided. When the line width of the fine metal wire constituting the electrode pattern is A μm and the thin metal wire constituting the frame shape is B μm, the following equation (1) is satisfied between A and B: The touch panel according to claim 10.
B ≧ 2A Formula (1) When the line width of the fine metal wire constituting the electrode pattern is A μm and the fine wire wire constituting the frame shape is B μm, the following equation (2) is satisfied between A and B: The touch panel according to claim 10.
B ≧ A + 5 Expression (2) The touch panel according to any one of the electrode surface resistivity 4ohm / sq terminals. Above 80 [Omega / sq. Or less is claims 1 to 12. A conductive sheet for a touch panel comprising a thin metal wire having a line width of 0.7 to 9 μm and having an electrode pattern provided in a sensing region and an electrode terminal electrically connected to an end of the electrode pattern. And
The said electrode terminal is a conductive sheet for touchscreens containing the mesh shape which consists of a grid | lattice comprised by the metal fine wire. The conductive sheet for a touch panel according to claim 14, wherein the fine metal wires constituting the electrode pattern have a line width of 1 to 7 μm. The electrode pattern, together with a mesh shape made of the grating, the pitch of the mesh shape made from the lattice of the electrode terminals, according to claim 14 also 15 is denser than the pitch of the mesh shape made from the lattice of the electrode pattern Conductive sheet for touch panel .

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