Capacitance type touch screen

A capacitance type touch screen includes a cover lens and a film sensor. The film sensor includes a base film, first transparent electrodes arranged side by side extending in an A direction, second transparent electrodes insulated from the first electrodes and arranged side by side extending in B direction while crossing the first electrodes, a plurality of first lead wirings connected to the first electrodes and drawn to connection terminals, and a plurality of second lead wirings connected to the second electrodes and drawn to connection terminals. The first and second wirings are hidden by the cover lens decorated area. The film sensor includes a top-plate-corresponding-portion facing the cover lens top plate rear surface, and rising portions facing a rear surface of at least one of the first and second side plates. All or most of the second wirings is positioned in the rising portions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. National stage application claims priority under 35 U.S.C. §119(a) to Japanese Patent Application No. 2011-080810, filed in Japan on Mar. 31, 2011, the entire contents of Japanese Patent Application No. 2011-080810 are hereby incorporated herein by reference.

BACKGROUND

1. Field of the Invention

The present invention relates to a capacitance type touch screen exercising touch input function with a film sensor adhered to a rear surface of the cover.

2. Background Information

Conventionally, in personal digital assistants such as PDA and handy terminals, OA equipment such as copy machines, facsimiles, electronic devices such as smartphones, cellular phones, portable game devices, electronic dictionaries, car navigation systems, small PCs, and various household electrical appliances, a cover lens is provided in front of the liquid crystal display (LCD), in order to protect the surface of the liquid crystal display from the damage or contamination. In addition, recently, in order to improve convenience for input operation with signals, after assembling a laminated layer of a plate-like cover lens and a film sensor, the assembly is provided for use in front of the liquid crystal display of the electronic devices.

Specifically, there is a capacitance type touch screen including the following cover lens and film sensor. The cover lens is plate-like, and includes a see-through area and a decorated area other than the see-through area. The film sensor is adhered to a rear surface of the cover lens. The film sensor includes a base film, a plurality of first transparent electrodes, a plurality of second transparent electrodes, a plurality of first lead wirings, and a plurality of second lead wirings. The plurality of first transparent electrodes are provided side by side on the base film. The plurality of second transparent electrodes are insulated from the first transparent electrodes and are arranged side by side crossing the first transparent electrodes. The plurality of first lead wirings are connected to the first transparent electrodes and drawn to connection terminals. The plurality of second lead wirings are connected to the second transparent electrodes and drawn to connection terminals. In an overlapped portion of the cover lens and the film sensor, the first lead wirings and the second lead wirings are hidden by the decorated area.

Furthermore, there is a capacitance type touch screen disclosed in the Unexamined Patent Publication 2008-302600, which includes the following cover lens and the film sensor. The cover lens has a casing structure composed of a rectangular top plate, a first side plate connected to one side of the top plate, and a second side plate connected to another side of the top plate opposite to the first side plate. The film sensor is provided only on the rear surface of the top plate of the cover lens.

SUMMARY

However, as shown in Unexamined Patent Publication 2008-302600, since a configuration is employed in which the film sensor103is provided only on the rear surface of the top plate121of the cover lens102, it is necessary to form a part of the top plate121of the cover lens102which covers the first lead wirings107and the second lead wirings108of the film sensor103as the decorated area102B, not as the see-through area102A, as shown inFIG. 18. Accordingly, a frame portion is defined in the peripheries of the top plate121. Although the market has been demanding a further narrowing of the frame, the extent achievable by narrowing a pitch between lead wirings arranged side by side is limited.

In order to solve the problem, it is an object of the present invention to provide a capacitance type touch screen that makes it possible to achieve a non-conventional frame narrowing of the touch screen or that makes the touch screen frameless.

Hereinafter, a plurality of aspects as means for solving problems will be explained. The aspects can be combined with each other as necessary.

A capacitance type touch screen according to one aspect of the present invention includes a cover lens and a film sensor. The cover lens includes a top plate, and a first side plate and a second side plate connected to two sides of the top plate along a second direction perpendicular to a first direction of the top plate, the cover lens having a see-through area and a decorated area other than the see-through area.

The film sensor is adhered to a rear surface of the cover lens.

The film sensor includes a base film, a plurality of first transparent electrodes arranged on the base film side by side, extending in the first direction, a plurality of second transparent electrodes arranged side by side so as to extend in the second direction and cross the first transparent electrodes, while being insulated from the plurality of first transparent electrodes, a plurality of first lead wirings connected the first transparent electrodes and drawn to connection terminals, and a plurality of second lead wirings connected to the second transparent electrodes and led out to connection terminals.

The first lead wirings and the second lead wirings are hidden by the decorated area of the cover lens.

The film sensor includes a top plate corresponding portion opposite to the rear surface of the top plate of the cover lens, and a rising portion facing at least one of the rear surfaces of the first side plate and the second side plate.

All or most of the second lead wirings are positioned in the rising portion.

It is acceptable that an inside R size of a bent portion of the film sensor is 1 to 4 mm.

It is acceptable that a part of the second transparent electrodes is positioned in the rising portion.

In this case, the transparent electrodes positioned in the rising portion are formed as a conductive patterned layer including a binder resin and silver nanofiber or carbon nanotube in the binder resin.

The capacitance type touch screen may further comprise a flexible display disposed on the rear surface of the film sensor. In this case, the flexible display has a second rising portion corresponding to the rising portion of the film sensor. The see-through area of the cover lens extends from the top plate to the side plate, facing the rising portion of the film sensor.

It is acceptable that the film sensor has been molded so as to have the rising portion before the film sensor is adhered to the cover lens.

It is acceptable that the film sensor has been molded so as to extend along the first side plate and the second side plate of the cover lens.

It is acceptable that a lower end of the rising portion of the film sensor is positioned lower than a lower end of the corresponding side plate of the cover lens corresponding to the rising portion.

It is acceptable that the film sensor includes a first base film supporting the first transparent electrodes and the first lead wirings, and a second base film supporting the second transparent electrodes and the second lead wirings. The second base film is different from the first base film in size. In this case, the first base film corresponds to only the rear surface of the top plate, and the second base film includes a first portion corresponding to the rear surface of the top plate, and a second portion and a third portion respectively corresponding to the rear surfaces of the first side plate and the second side plate.

Since the capacitance type touch screen is configured as described above, the position where the lead line wirings are formed is not limited to within the top plate of the cover lens, so that the inner edge of the decorated area hiding the lead line wirings can be formed very close to the outer periphery of the top plate, thereby achieving non-conventional frame narrowing of the decorated area in the top plate, or making the decorated area frameless.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment will be explained with reference to drawings.

First Embodiment

A touch screen1shown inFIG. 1andFIG. 2includes a cover lens2, and a film sensor3adhered to a rear surface of the cover lens2.

The cover lens2protects a display provided on a rear side of the cover lens2from external impact or the like. The cover lens2employs a casing structure composed of a rectangular top plate21, a first side plate22of a thin rectangle connected to one side of the top plate21, and a second side plate23of a thin rectangle connected to another side of the top plate21opposite to the first side plate22. In this embodiment, the top plate21extends in A direction (first direction) in the figure, and the first side plate22and the second side plate23are connected to two sides of the top plate21along B direction (second direction), which is perpendicular to A direction. It should be noted that the top plate does not have to be rectangular, and the side plates do not have to be thin rectangles.

The top plate21of the cover lens2is preferably planar, typically. The reason is that if the top plate21were a curved surface, air or air bubbles might enter between the cover lens2and the film sensor3when the film sensor3is adhered along the rear surface of the top plate21, thereby deteriorating the touch input function and the appearance of the touch input screen.

The material for the cover lens2has to have a high transparency and impact resistance, and may be a glass plate, a resin plate or the like. The material for the glass plate is preferably a chemically strengthened glass, and the material for the resin plate is preferably acrylic resin, polycarbonate resin or the like.

The thickness of the cover lens2is preferably 0.5 to 2 mm. If the thickness is beyond 2 mm, problems are likely to occur, such as extreme decrease in the light transmittance, blurring of the image on the display provided on the rear side of the cover lens2, and darkening of the image color. In contrast, if the thickness is below 0.5 mm, the cover lens2cannot withstand various external impacts when in use, and cannot protect the display provided on the rear side of the cover lens2.

The cover lens2includes a see-through area2A through which image on the display provided on the rear side thereof is seen, and an opaque decorated area2B other than the see-through area2A. The decorated area2B serves as a part for hiding wirings which connect the transparent electrodes of the film sensor3to a control circuit.

An optically transparent adhesive (Optical Clear Adhesive: OCA)10is used to adhere the film sensor3to the cover lens2. According to the present embodiment, the optically transparent adhesive10is provided on at least the rear surface of the top plate21of the cover lens2. As shown inFIG. 1, since the optically transparent adhesive10is provided only on the rear surface of the top plate21, it is easy to adhere the film sensor3to the cover lens2. In contrast, if the optically transparent adhesive10were provided on the rear surfaces of the first side plate22and second side plate23as well as the rear surface of the top plate21, the film sensor3can be reliably adhered to the cover lens2.

The optically transparent adhesive10can be made of acrylic adhesive and rubber adhesive, and the acrylic adhesive is preferable in light of transparency. Such adhesive may contain, other than tacky polymer component, plasticizer, adhesiveness applying component, or the like, but additives that may deteriorate transparency are not preferable. As the tacky polymer that is the main component of the acrylic adhesive, copolymer of a mixture of monomers may be preferably used, and may include, as a main component, (meta) acrylic ester in which carbon number of alkyl group is 1 to 10 such as ester 2-ethylhexyl acrylate, butyl acrylate, isooctyl acrylate, butyl methacrylate, and propyl methacrylate, and unsaturated monomer with functional groups such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, hydroxyethyl acrylate, hydroxyethyl methacrylate. In addition, as the tacky polymer that is the main component of the rubber adhesive, stylene/butadiene random copolymer, stylene/isoprene block copolymer, and natural rubber may be preferably used.

The film sensor3includes, as a basic structure, a base film4, a plurality of first transparent electrodes5, a plurality of second transparent electrodes6, a plurality of first lead wirings7, and a plurality of second lead wirings8. The plurality of first transparent electrodes5are provided side by side on the base film4. The plurality of second transparent electrodes6are insulated from the first transparent electrodes5, and are provided side by side crossing the first transparent electrodes5. The plurality of first lead wirings7are connected to the first transparent electrodes5, and are drawn to the connection terminals. The plurality of second lead wirings8are connected to the second transparent electrodes6, and are drawn to the connection terminals. In the overlapped portion of the cover lens2and the film sensor3, the first lead wirings7and the second lead wirings8are hidden by the decorated area2B.

The first transparent electrodes5extend in A direction in the figure, and the second transparent electrodes6extend in B direction in the figure.

The film sensor3includes a top-plate-corresponding-portion31opposite to the rear surface of the top plate21A of the cover lens2, and rising portions32,33facing respectively the rear surfaces of the first side plate22A and the second side plate22B of the cover lens2.

The second lead wirings8includes a first portion8acorresponding to the rising portions32,33, and a second portion8bcorresponding to the top-plate-corresponding-portion31. More specifically, the first portion8aincludes a portion extending from the second transparent electrodes6in the width direction of the rising portions32,33, a portion extending in the length direction of the rising portions32,33(A direction in the figure), and a portion extending from the second portion8bin the width direction of the rising portions32,33. According to the present embodiment, there is a larger amount of the first portion8ain the second lead wirings8than that of the first portion8a. The second portion8bpreferably occupies 70% or more of the entire second lead wirings8, more preferably 80% or more, further preferably 90% or more.

While the film sensor3has the above-described basic structure, there are several kinds of film sensor3which have different configuration or use from each other in minor aspects. Examples (1) to (7) are shown hereinbelow.

Referring toFIG. 7, the film sensor3includes a base film4, a plurality of first transparent electrodes5, a plurality of second transparent electrodes6, intermediate insulation layers9, a plurality of first lead wirings7, and a plurality of second lead wirings8. The plurality of first transparent electrodes5are provided side by side on the base film4. The plurality of second transparent electrodes6are provided on a surface of the base film4on which the first transparent electrodes5are formed, and are arranged side by side crossing the first transparent electrodes5. The intermediate insulation layers9are provided between the crossing portions of the first transparent electrodes5and the second transparent electrodes6. The plurality of first lead wirings7are connected to the first transparent electrodes5, and are drawn to connection terminals. The plurality of second lead wiring8are connected to the second transparent electrodes6, and are drawn to connection terminals. A side of the film sensor3corresponding to the base film4faces the cover lens2.

A side of the film sensor3opposite to the base film4faces the cover lens2, and the rest of the structure is the same as that in the above (1).

The film sensor3includes, as shown inFIG. 8, a base film4, a plurality of first transparent electrodes5, a plurality of second transparent electrodes6, a plurality of first lead wirings7, and a plurality of second lead wirings8. The plurality of first transparent electrodes5are arranged side by side on the base film4. The plurality of second transparent electrodes6are arranged side by side on a surface of the base film4opposite to the surface on which the first transparent electrodes5are formed, crossing the first transparent electrodes5. The plurality of first lead wirings7are connected to the first transparent electrodes5, and are drawn to the connection terminals. The plurality of second lead wirings8are connected to the second transparent electrodes6, and are drawn to the connection terminals.

Unlike the above (1) through (3), the film sensor3includes an additional base film. The film sensor3includes, as shown inFIG. 9, a first base film4A, a plurality of first transparent electrodes5, a plurality of first lead wirings7, a second base film4B, a plurality of second transparent electrodes6, and a plurality of second lead wirings8. The plurality of first transparent electrodes5are arranged side by side on the first base film4A. The plurality of first lead wirings7are connected to the first transparent electrodes5, and are drawn to the connection terminals. The second base film4B is adhered to and covers the first transparent electrodes5and the first lead wirings7except the connection terminals. The plurality of second transparent electrodes6are arranged side by side on the second base film4B, crossing the first transparent electrodes5. The plurality of second lead wirings8are, on the second base film4B, connected to the second transparent electrodes6, and are drawn to the connection terminals. The first base film4A faces the cover lens2.

The second base film4B faces the cover lens2, and the rest of the structure is the same as that of the above (4).

Unlike the above (1) through (3), the film sensor3includes an additional base film. The film sensor3includes, as shown inFIG. 10, a first base film4A, a plurality of first transparent electrodes5, a second base film4B, a plurality of second transparent electrodes6, a plurality of first lead wirings7, and a plurality of second lead wiring8. The plurality of first transparent electrodes5are arranged on the first base film4A. The second base film4B is adhered to a surface of the first base film4A opposite to the surface on which the first transparent electrodes5are formed. The plurality of second transparent electrodes6are arranged side by side on the surface of the second base film4B opposite to the surface on which the first base film4A is adhered, crossing the first transparent electrodes5. The plurality of first lead wirings7are connected to the first transparent electrodes5, and are drawn to the connection terminals. The plurality of second lead wirings8are connected to the second transparent electrodes6, and are drawn to the connection terminals.

(7) Having a Shield Layer

In addition to the configuration of the above (1) through (6), a shield film (not shown) is adhered to a backend surface of the film sensor3.

Regarding the typical thickness of the base films4,4A,4B, in general, the thickness of the individual film is 20 μm or more, and the total thickness of the films used in the film sensor3is 500 μm or less. If the thickness of the individual film is below 20 μm, it becomes difficult to handle the film during manufacturing, and if the total thickness is beyond 500 μm, the translucency is deteriorated.

In the case of the film sensor3in the above (4) through (6) of the double base layer type, a base film, which supports the lead wirings which are not disposed on a portion corresponding to the first side plate22and the second side plate23, can be designed to a size such that the base film is disposed only on a side close to the rear surface of the top plate21of the cover lens2.

For example, as shown inFIG. 16, the film sensor3, adhered to the rear surface of the cover lens2, includes a first base film4A, a plurality of first transparent electrodes5, a second base film4B, a plurality of second transparent electrodes6, a plurality of first lead line wirings7, and a plurality of second lead line wirings8. The plurality of first transparent electrodes5are arranged side by side on the first base film4A. The second base film4B is different from the first base film4A in size. The second transparent electrodes6are insulated from the first transparent electrodes5, and are arranged on the second base film4B, crossing the first transparent electrodes5. The plurality of first lead wirings7are connected to the first transparent electrodes5, and are drawn to the connection terminals. The plurality of second lead wirings8are connected to the second transparent electrodes6, and are drawn to the connection terminals. In an overlapped portion of the cover lens2and the film sensor3, the first lead wirings7and the second lead wiring8are hidden by a decorated area2B.

As shown inFIG. 16, the first base film4A, supporting the first transparent electrodes5and the first lead wirings7, is disposed only on a side close to the rear surface of the top plate21, and the second base film4B, supporting the second transparent electrodes6and the second lead wirings8, is disposed at portions that also include those corresponding to the rear surfaces of the first side plate22and the second side plate23. More specifically, the second base film4B includes a first portion4C corresponding to the rear surface of the top plate, a second portion4D and a third portion4E respectively corresponding to the rear surfaces of the first side plate22and the second side plate23.

In this case, it is substantially necessary to face only one of the two base films to the side plates. Accordingly, it is easy to bend the film sensor3and adhere the film sensor3.

The pattern of the first transparent electrodes5and the second transparent electrodes6will be explained with reference toFIG. 14.

The first transparent electrodes5include rhombic electrodes51, which look rhombic when viewed in a planar manner, and connection wirings52penetrating the rhombic electrodes51in a vertical direction in the figure (Y direction). The plurality of rhombic electrode51and the connection wirings52are electrically connected with each other. The connection wirings52and the plurality of rhombic electrode51penetrated by the connection wirings52are defined as one set, and the one set is repeatedly arranged in a lateral direction (X direction). On the other hand, the second transparent electrodes6include a plurality of rhombic electrodes61, and connection wirings62penetrating the rhombic electrodes61. In this case, the extending direction of the connection wirings62is a lateral direction (X direction) in the figure, unlike that of the connection wirings52. Accordingly, a set of the connection wirings62and plurality of rhombic electrodes61penetrated by the connection wiring62is repeatedly arranged in the vertical direction in the figure (Y direction).

As apparent fromFIG. 14, the rhombic electrodes51and the rhombic electrodes61are arranged to be complementary with each other. In other words, the plurality of rhombic electrodes61are arranged so as to fill rhombic gaps defined when the rhombic electrodes51are arranged in a matrix. InFIG. 14, triangle electrodes are provided at the ends of the groups of the rhombic electrodes51,61aligned in one line. The triangle electrodes are provided in order to form a rectangular sensor effective area corresponding to the rectangular see-through area2A, and to avoid what is called skeletal structure of the electrodes in which the transmittance becomes uneven. The triangle electrodes can be omitted.

Since the X-direction electrodes and Y-direction electrodes are arranged so as to form a lattice in a plane view, if a finger of the user or the like touches any position on the lattice via the cover lens2covering the film sensor3(position indicated by a circle FR of the dashed line), a capacitor is formed between the finger or the like and the X-direction electrode touched by the finger, and a capacitor is formed between the finger or the like and the Y-direction electrode touched by the finger. The formation of the capacitor increases the capacitance of the X-direction electrode and the Y-direction electrode touched by the finger. A position detecting unit in an outside circuit detects the amount of change in capacitance occurring in this case, or detects the X-direction electrode and Y-direction electrode having the largest capacitance. Accordingly, it is possible to obtain a location where the finger touches in the see-through area2A as a set of X-coordinate value and Y-coordinate value having a particular value

The materials of the first transparent electrodes5and the second transparent electrodes6preferably extert a light transmittance (translucency) of 80% or more and a surface resistance value (conductivity) of a few mΩ to a few hundred Ω. The electrodes can be formed by a metallic oxide such as indium oxide, tin oxide, indium tin oxide (ITO), and tin antimonite, or a metal such as gold, silver, copper, platinum, palladium, aluminum, and rhodium. As methods of forming the first transparent electrodes5and the second transparent electrodes6made of the above-described materials, there exist methods such as forming a transparent conductive film with a method such as PVD methods such as a sputtering method, a vacuum deposition method, and an ion plating method, a CVD method, or a coating method and then patterning is performed through etching, and a printing method.

The first lead wirings7and the second lead wirings8are typically formed by screen printing, but the forming method is not particularly limited. The material for the first lead wirings7and the second lead wirings8is generally a silver paste, a copper paste, or a paste of silver and carbon, but other materials can be selected as long as the material keeps a constant volume resistance and is stable.

The first lead wirings7and the second lead wirings8can be constituted with a dual layer structure including a transparent conductive layer made of the same material as that of the first transparent electrodes5and the second transparent electrodes6, and a metallic layer laminated on the transparent conductive layer. The material for the metallic layer may be aluminum, nickel, copper, silver, tin, and so on, for example. As methods of forming the first lead wirings7and the second lead wirings8, there exists a method in which the transparent conductive film and the metallic film are laminated with a PVD method such as a sputtering method, a vacuum deposition method, and an ion plating method, a CVD method, or a coating method, and then patterning is performed through etching.

The materials for the intermediate insulation layer9in the examples (1) and (2) may be thermosetting resin such as polyester resin, and ultraviolet curable resin such as acrylic resin.

The shield film in the example (7) may be formed by forming a transparent conductive film, made of the same material as that of the first transparent electrodes5and the second transparent electrodes6, onto an entire surface of a resin film made of the same material as that of the base film4.

For the adhesion when using a plurality of films in the examples (4) through (7), the optically transparent adhesive10is used for adhering the film sensor3to the cover lens2(in the figures, the optically transparent adhesive10is omitted.).

The feature of the present embodiment includes using a molded film sensor3. In the first embodiment, the film sensor3includes, as shown inFIG. 1, the rising portions32,33so as to face the rear surfaces of the top plate21, the first side plate22and the second side plate23of the cover lens2. Most of the lead line wirings8, connected to the plurality of second transparent electrodes6that have an axis extending in a direction perpendicular to the rising portion32,33, are disposed in a portion of the rising portions corresponding to the first side plate22and the second side plate23.

Since this configuration makes it possible for the lead line wirings to be formed at positions that are not only within the top plate21of the cover lens2, the inner edge of the decorated area2B that hides the lead line wirings can be formed very close to the outer periphery of the top plate21, so that frame narrowing of the decorated area2B is achieved in the top plate21. In the ideal situation, the top plate21can be frameless.

Among the film sensors3exemplified in the above (1) to (7), in the film sensors3in the examples (1), (3), (4) and (6), as shown inFIG. 1andFIG. 2, the molded film sensor3extends off from one of the two sides21A where the first side plate22and the second side plate23are not formed, one end22A (which is either the right end or the left end) of the first side plate22near the side21A of the top plate21, and one end23A (which is either the right end or the left end) of the second side plate23near the side21A of the top plate21, such that the connection terminals11of the first lead wirings7and the second lead wirings8are not covered by the cover lens2.

This configuration makes it possible for the FPC (not shown) connected at the connection terminals11not to be positioned between the cover lens2and the film sensor3, so that it is easier to adhere the film sensor3to the cover lens2and the FPC does not go off after getting stuck with the end surface of the cover lens2.

It is preferable that the film sensor3is risen to have an inside R size of 1 to 4 mm. Due to the roundness of the inside R size of 1 mm or more, and not being a right angle, at parts of the film sensor3that correspond to the first side plate and the second side plate, it is possible to prevent the lead line wirings from being destroyed and broken. It should be noted that, if the inner R size is beyond 4 mm, the frame narrowing effect is reduced.

Although the film sensor3is positioned so as to correspond to the rear surfaces of the top plate21, first side plate22and second side plate23of the cover lens2, the front surface shape of the film sensor3according to the present embodiment does not have to correspond to the rear surface shape of the cover lens2completely. In other words, it includes the shape of the front surface of the film sensor3that is similar to the shape of the rear surface of the cover lens2, e.g., there may be a wider distance between the outer R portion of the film sensor3and the cover lens2.

In addition, according to the present embodiment, the size of the film sensor3is designed so as to satisfy the following conditions. The lower end of the molded film sensor3is positioned at the same level with or higher than the lower ends of the first side plate22and second side plate23of the cover lens2. This configuration makes it possible to reduce the height of the electronic devices incorporating the touch screen1.

Second Embodiment

The touch screen1according to the present embodiment is different from one according to the first embodiment in that the size of the film sensor3is designed such that the lower end of the molded film sensor3is positioned lower than the lower ends of the first side plate22and second side plate23of the cover lens2(Refer toFIG. 3andFIG. 4).

This configuration allows users to grab a portion sticking out from the cover lens2when the film sensor3is to be adhered to the cover lens2, thereby improving the handling of the film sensor3.

Third Embodiment

In the touch screen1according to the present embodiment, at least one of the first transparent electrodes5and the second transparent electrodes6may be present in the rising portions32,33of the film sensor3. In the present embodiment, both ends of the second transparent electrodes6extend to the rising portions32,33(refer toFIG. 17), which is different from the first embodiment.

This configuration allows the sensing area to be formed beyond the outer periphery of the top plate21, so that it becomes further ensured that the frame of the decorated area2B in the top plate21is narrowed or that the decorated area2B is frameless. In addition, the portion of the decorated area2B that covers the first side plate22and the second side plate23can be utilized for inputting.

In the case where the transparent electrodes are also formed in the rising portions of the film sensor, it is preferable that the transparent electrodes are formed as a conductive patterned layer including silver nanofiber or carbon nanotube in the binder resin. Since the conductive patterned layer including silver nanofiber or carbon nanotube (CNT) has an excellent flexibility and formability, the transparent electrodes made of either of them is not damaged due to the bending of the film sensor3. In addition, according to the present embodiment, it is preferable that the optically transparent adhesive10used for adhering the film sensor3to the cover lens2is provided not only on the rear surface of the top plate21of the cover lens2, but also on the rear surfaces of the first side plate22and the second side plate23.

The material for the transparent electrodes may also preferably be polyethylenedioxythiophene (PEDOT).

Fourth Embodiment

In the touch screen according to the present embodiment, the flexible display12is disposed on the rear surface of the film sensor3formed with the rising portions32,33. More specifically, the flexible display12includes a main surface portion12aand a rising portion12b. The see-through area2A of the cover lens2extends not only to the top plate21but also to the first side plate22and the second side plate23(refer toFIG. 6), which is different from the third embodiment.

This configuration allows users to input instructions by touching the first side plate22and the second side plate23of the cover lens2too, while seeing through the display screen. It is possible to use, as the flexible display12, a publicly known flexible display as well as organic light emitting diode (OLED), and electronic papers. It is acceptable that the flexible display12and the film sensor3are bonded to each other.

Fifth Embodiment

In the touch screen according to the present embodiment, the film sensor3has been molded so as to have rising portions before the film sensor3is adhered to the cover lens2, which is different from the first embodiment.

Since this configuration allows the film sensor3to be adhered to the cover lens2without bending the film sensor3along the rear surface of the cover lens2, it becomes easy for the film sensor3to be adhered to the cover lens2, and it becomes possible to reliably bend the film sensor3to a certain shape.

Preferably, the film sensor3is molded with a R bending process (Refer toFIG. 11). The R bending process is a process of rounding the corner portions, so as to form not a right angle. One of the methods of the R bending process is, for example, to place a portion of the film sensor3to be bent along a center line of a heater (pipe heater)13protected by a stainless pipe or the like, to heat and soften the portion of the film sensor3in contact with the pipe heater13, and to bend it to a target angle quickly after it is sufficiently softened. The inside R size of the R bending process is 1 to 4 mm in the above-mentioned film sensor3. It should be noted that methods other than the above-described method can also be employed as a method of the R bending.

Function and Effects of the Embodiment

The capacitance type touch screen1(one example of the touch screen) includes a cover lens2(one example of the cover lens) and the film sensor3(one example of the film sensor).

The cover lens2includes the top plate21(one example of the top plate) and the first side plate22and the second side plate23that are connected to two sides of the top plate21in B direction (one example of the second direction) that is perpendicular to A direction (one example of the first direction) of the top plate21. The cover lens2includes a see-through area2A (one example of the see-through area), and a decorated area2B (one example of the decorated area) other than the see-through area2A. The film sensor3is adhered to the rear surface of the cover lens2.

The film sensor3includes the base film4(one example of the base film), the plurality of first transparent electrodes5(one example of the first transparent electrodes), the plurality of second transparent electrodes6(one example of the second transparent electrodes), the plurality of first lead wirings7(one example of the first lead wirings), and the plurality of second lead wirings8(one example of the second lead wirings). The plurality of first transparent electrodes5are arranged side by side on the base film4and extending in A direction. The plurality of second transparent electrodes6are insulated from the first transparent electrodes5, and extend in B direction while being arranged side by side, crossing the first transparent electrodes5. The plurality of first lead wirings7are connected to the first transparent electrodes5, and drawn to connection terminals. The plurality of second lead wirings8are connected to the second transparent electrodes6, and are drawn to connection terminals.

The first lead wirings7and the second lead wirings8are hidden by the decorated area2B of the cover lens2.

The film sensor3includes a top plate-corresponding portion31(one example of the top plate corresponding portion) opposite to the rear surface of the top plate2A of the cover lens2, and rising portions32,33(one example of the rising portion) facing at least one of the rear surfaces of the first side plate22and the second side plate23.

All or most of the second lead wirings8is positioned in the rising portions32,33.

Since the capacitance type touch screen1is configured as described above, the position where the second lead wirings8are formed is not limited to within the top plate21A of the cover lens2, and the inner edge of the decorated area2B hiding the second lead wirings8can be formed very close to the outer periphery of the top plate21A, thereby achieving non-conventional frame narrowing of the decorated area of the top plate, or a frameless top plate.

Variations

Although one embodiment according to the present invention was explained above, the present invention is not limited to the above-described embodiment. The embodiment can be altered in various ways without departing from the scope of the present invention. Particularly, a plurality of embodiments and variations can be arbitrarily combined with each other as necessary.

(a) A casing structure can be employed in which the cover lens2includes a third side surface plate24of a thin rectangle formed along a side opposite to the side21A near the connection terminals11, where the first side plate22and the second side plate23of the top plate21are not formed. In this structure, right and left ends of the third side surface plate24are continuously connected respectively with the first side plate22and the second side plate23(refer toFIG. 12).

(b) In the description of the first embodiment, it is mentioned that the top plate21of the cover lens2is typically preferably planar. However, as shown inFIG. 13, a curved surface can be used as the cover lens2having a shape in which the surface is evenly rising as it approaches the center line from the first side plate22and the second side plate23. Such a curved surface can be used because it does not exert any bonding difficulty, similar to the case of a planar surface.

In the above-described embodiments and the variations, boundaries between the top plate and the side surface plates are clear and the side surface plates are flat plates. However, the present invention can be applied to a shape in which the top plate and the side plates are continuous with each other, with curvature, so that the boundaries between the top plate and the side plates are not necessarily clear (not shown).

(c) Although in the above-described embodiments, the transparent electrodes5,6are arranged so as to have the rhombic electrodes51and the rhombic electrodes61spread out (self capacitance), the transparent electrodes5,6of the film sensor3are not limited to this embodiment. For example, as shown inFIG. 15, the transparent electrode5,6may be band electrodes arranged in a matrix (mutual capacitance).

(d) According to the above-described embodiments, although the film sensor3includes rising portions to face the rear surfaces of the top plate21, the first side plate22, and the second side plate23of the cover lens2, the film sensor3is not limited to this example. For example, the film sensor3may have a rising portion to face the rear surface of the top plate21and one of the first side plate22and the second side plate23of the cover lens2.

In the example shown inFIG. 5, the film sensor3has a rising portion32facing the first side plate22. Accordingly, the second lead wirings8has only a first portion8acorresponding to the rising portion32,33. More specifically, the first portion8aincludes a portion extending from the second transparent electrodes6in the width direction of the rising portions32,33, and a portion extending in the length direction of the rising portions32,33(A direction in the figure).

(e) As shown inFIG. 1,FIG. 3andFIG. 5, in a case where the optically transparent adhesive10is disposed only on the rear surface of the top plate21, it is acceptable that the lead line wirings of the film sensor3disposed on a portion corresponding to the first side plate and the second side plate are protected by an insulation layer. The configuration prevents the lead line wirings from being rubbed and damaged by the rear surfaces of the first side plate and the second side plate (not shown).

(f) The first side plate22, the second side plate23, and the third side surface plate24of the cover lens2may be formed with cutout portions at the lower end or right and left ends for headphone terminals or the like, or with claw portions for engaging the cover lens2or the like (not shown).

The present invention relates to a capacitance type touch screen incorporated into a part of a casing of the personal digital assistants such as PDAs and handy terminals, OA equipment such as copy machines and facsimiles, and various home appliances such as smartphones, cellular phones, portable game devices, electronic dictionaries, car navigation systems, and small PCs.