Touch panel

Abstract

The present invention aims to provide a flexible touch panel. Alternatively, it aims to achieve both thinning of the touch panel and high detection sensitivity. A touch panel is provided comprising a first substrate having flexibility, a first insulating layer on the first substrate, a transistor and a light-emitting element on the first insulating layer, a color filter on the light-emitting element, a pair of sensor electrodes on the color filter, a second insulating layer on the pair of sensor electrodes, a second substrate having flexibility on the second insulating layer, and a protective layer on the second substrate. Additionally, the touch panel includes a first adhesive layer between the light-emitting element and the color filter, wherein the thickness of the first substrate and the second substrate is each 1 μm or more and 200 μm or less, and the thickness of the first adhesive layer is 50 nm or more and 10 μm or less, and there is a region in which the thickness of the first adhesive layer is 50 nm or more and 10 μm or less.

Description

Technology Field

[0001] One embodiment of the present invention relates to a display device. In particular, it relates to a display device that is flexible and can be bent. Additionally, one embodiment of the present invention relates to a touch panel. In particular, it relates to a touch panel that is flexible and can be bent.

[0002] Furthermore, one embodiment of the present invention is not limited to the technical field described above. The technical field of one embodiment of the invention disclosed in this specification, etc., relates to an object, a method, or a method of manufacturing. Alternatively, one embodiment of the present invention relates to a process, a machine, a product, or a composition of matter. Therefore, more specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification may include a semiconductor device, a display device, a light-emitting device, a capacitor device, a memory device, and methods for driving the same or methods for manufacturing the same. Background Technology

[0003] In recent years, display devices are expected to be applied to a wide range of uses, and diversification is required. For example, as portable information terminals, smartphones and tablet-type devices equipped with touch panels are becoming thinner, more high-performance, and more multifunctional.

[0004] In addition, Patent Document 1 discloses a flexible active matrix type light-emitting device having a switching element, such as a transistor or an organic EL element, on a film substrate. Prior art literature

[0005] Japanese Patent Publication No. 2003-174153 The problem to be solved

[0006] There is a demand for a touch panel that adds the function of inputting by touching the screen with a finger, etc., as a user interface to a display device that has been made thin enough to be flexible.

[0007] One embodiment of the present invention has as its objective to provide a flexible touch panel. Alternatively, it has as its objective to achieve both thinning of the touch panel and high detection sensitivity.

[0008] Alternatively, providing a new display device is one of the tasks. Alternatively, providing a new touch sensor is one of the tasks. Alternatively, providing a new touch panel is one of the tasks.

[0009] Furthermore, the description of the aforementioned problem does not prevent the existence of other problems. One embodiment of the present invention is not required to solve all of the aforementioned problems. In addition, problems other than those described above become naturally apparent from the description in the specification, etc., and problems other than those described above can be derived from the description in the specification, etc. means of solving the problem

[0010] One embodiment of the present invention is a touch panel comprising a first substrate having flexibility, a first insulating layer on the first substrate, a transistor and a light-emitting element on the first insulating layer, a color filter on the light-emitting element, a pair of sensor electrodes on the color filter, a second insulating layer on the pair of sensor electrodes, a second substrate having flexibility on the second insulating layer, and a protective layer on the second substrate. Additionally, it includes a first adhesive layer between the light-emitting element and the color filter, wherein the thickness of the first substrate and the second substrate is each 1 μm or more and 200 μm or less, and the thickness of the first adhesive layer is 50 nm or more and 10 μm or less, and there is a region having a thickness of 50 nm or more and 10 μm or less.

[0011] In addition, a first conductive film is provided on the first insulating layer, and it is preferable that one of a pair of sensor electrodes and the first conductive film are electrically connected through a conductive connector.

[0012] In addition, another embodiment of the present invention is a touch panel comprising a first substrate having flexibility, a pair of sensor electrodes on the first substrate, a first insulating layer on the pair of sensor electrodes, a transistor and a light-emitting element on the first insulating layer, a color filter below the light-emitting element, a second insulating layer above the light-emitting element, a second substrate having flexibility on the second insulating layer, and a protective layer below the first substrate. In addition, it includes a first adhesive layer between the light-emitting element and the second insulating layer, wherein the thickness of the first substrate and the second substrate is each 1 μm or more and 200 μm or less, and the thickness of the first adhesive layer is 50 nm or more and 10 μm or less, and there is a region having a thickness of the first adhesive layer.

[0013] In addition, it is preferable to use an oxide semiconductor in the semiconductor layer where the channel of the above-mentioned transistor is formed.

[0014] In addition, polycrystalline silicon may be used in the semiconductor layer where the channel of the above-mentioned transistor is formed.

[0015] In addition, it is preferable that the protective layer comprises aluminum oxide or yttrium oxide.

[0016] In addition, it is preferable to include a second adhesive layer between the first insulating layer and the first substrate, wherein the thickness of the second adhesive layer is 50 nm or more and 10 μm or less.

[0017] In addition, it is preferable to include a third adhesive layer between the second insulating layer and the second substrate, wherein the thickness of the third adhesive layer is 50 nm or more and 10 μm or less. Effects of the invention

[0018] According to one embodiment of the present invention, a flexible touch panel can be provided. Alternatively, thinning of the touch panel and high detection sensitivity can be achieved simultaneously.

[0019] Alternatively, a novel display device, touch sensor, or touch panel may be provided. Furthermore, the description of the effects described above does not preclude the existence of other effects. Additionally, one embodiment of the present invention is not required to exhibit all of the effects described above. Furthermore, effects other than those described above become naturally apparent from the description in the specification, drawings, claims, etc., and effects other than those described above can be derived from the description in the specification, drawings, claims, etc. Brief explanation of the drawing

[0020] FIG. 1 is a drawing illustrating an example of the configuration of a touch panel. FIG. 2 is a drawing illustrating an example of the configuration of a touch panel. FIG. 3 is a drawing illustrating an example of the configuration of a touch panel. FIG. 4 is a drawing illustrating an example of the configuration of a touch panel. FIG. 5 is a drawing illustrating an example of the configuration of a touch panel. FIG. 6 is a drawing illustrating an example of the configuration of a touch panel. FIG. 7 is a drawing illustrating an example of the configuration of a touch panel. Figure 8 is a block diagram and timing chart of a touch sensor. Figure 9 is a circuit diagram of a touch sensor. FIG. 10 is a block diagram and timing chart of the display device. FIG. 11 is a diagram illustrating the operation of a display device and a touch sensor. FIG. 12 is a diagram illustrating the operation of a display device and a touch sensor. Fig. 13 is a block diagram of a touch panel. Figure 14 is a circuit diagram of a pixel. FIG. 15 is a timing chart for explaining the operation of a display device. FIG. 16 is a cross-sectional view of the device and a perspective view of the nozzle. FIG. 17 is a drawing illustrating an example of the configuration of an electronic device. FIG. 18 is a drawing illustrating an example of the configuration of an electronic device. Fig. 19 shows a Cs-corrected high-resolution TEM image of a cross-section of CAAC-OS and a schematic cross-sectional view of CAAC-OS. Fig. 20 is a Cs-corrected high-resolution TEM image in the plane of CAAC-OS. Figure 21 is a diagram illustrating the structural analysis of CAAC-OS and single-crystal oxide semiconductors by XRD. Figure 22 shows the electron diffraction pattern of CAAC-OS. Figure 23 is a graph showing the change in the crystal portion of In-Ga-Zn oxide due to electron irradiation. Specific details for implementing the invention

[0021] Embodiments are described in detail using the drawings. However, the present invention is not limited to the description below, and those skilled in the art will readily understand that various changes to its form and details can be made without departing from the spirit and scope of the invention. Accordingly, the present invention is not to be interpreted as being limited to the contents of the embodiments described below.

[0022] Furthermore, in describing the composition of the invention below, the same reference numerals are commonly used across different drawings for identical parts or parts having the same function, and their repeated description is omitted. Additionally, when referring to parts having the same function, the hatch pattern may be identical, and a specific reference numeral may not be assigned.

[0023] Additionally, in each drawing described herein, the size, layer thickness, or area of ​​each component may be exaggerated for clarity. Accordingly, embodiments of the present invention are not necessarily limited to that scale.

[0024] In addition, ordinal numbers such as 'first', 'second', etc. in this specification are intended to avoid confusion of components and are not numerically limited.

[0025] (Embodiment 1)

[0026] In this embodiment, an example of the configuration of a touch panel according to one form of the present invention will be described with reference to the drawings.

[0027] [Example of touch panel configuration]

[0028] Figure 1 (A) is a schematic perspective view of a touch panel (100) exemplified below.

[0029] The touch panel (100) includes at least a display device (110) and a touch sensor (120) between a flexible substrate (101) and a flexible substrate (102).

[0030] FIG. 1 (B) is a perspective schematic diagram showing the touch sensor (120) in FIG. 1 (A), and FIG. 1 (C) is a perspective schematic diagram showing the configuration including the display device (110), wiring (131), wiring (132), and wiring (144) in FIG. 1 (A).

[0031] For example, a capacitive touch sensor can be applied as the touch sensor (120). Capacitive methods include surface capacitive methods and projected capacitive methods. Additionally, projected capacitive methods mainly include magnetic capacitance methods and mutual capacitance methods depending on the driving method. Using a mutual capacitance method is desirable because it enables multi-point simultaneous detection.

[0032] The following describes the case where a projected capacitive touch sensor is applied.

[0033] In addition, various sensors capable of detecting proximity or contact of a detection target, such as a finger (e.g., optical sensors using photoelectric conversion elements, pressure-sensitive sensors using pressure-sensitive elements), may also be applied.

[0034] The touch sensor (120) has a plurality of electrodes (121) and a plurality of electrodes (122). The electrode (121) is electrically connected to any of the plurality of wires (131), and the electrode (122) is electrically connected to any of the plurality of wires (132). An FPC (142) is electrically connected to the wire (131). Additionally, an FPC (143) is electrically connected to the wire (132).

[0035] The electrode (121) extends in one direction. Additionally, the electrode (122) extends in a direction intersecting the electrode (121). Furthermore, a dielectric layer is provided between the electrode (121) and the electrode (122), and a capacitance is formed at the intersection of them. The touch sensor (120) has a configuration in which a plurality of capacitance elements formed by a plurality of electrodes (121), a plurality of electrodes (122), and a dielectric layer between them are arranged in a matrix form.

[0036] Additionally, it is desirable that the electrode (121) and the electrode (122) have light transmittance. Here, as shown in (B) of FIG. 1, it is desirable that the electrode (121) and the electrode (122) be arranged so that there is as little gap as possible. Additionally, a dummy electrode containing a conductive film identical to that of the electrode (121) or the electrode (122) may be provided between these electrodes. In this way, by minimizing the gap between the electrode (121) and the electrode (122), non-uniformity of transmittance can be reduced. As a result, non-uniformity of brightness of light transmitted through the touch sensor (120) can be reduced.

[0037] The display device (110) includes at least a display unit (111) including a plurality of pixels and wiring (144) for supplying a signal or power to the display unit (111). The pixels included in the display unit (111) preferably have transistors and display elements. As a display element, an organic EL element can be used as a representative example.

[0038] Additionally, FIG. 1 illustrates a configuration in which a display device (110) has a display unit (111) as well as a driving circuit (112). As the driving circuit (112), a circuit that functions as, for example, a scan line driving circuit, a signal line driving circuit, etc. can be used.

[0039] An FPC (141) is electrically connected to the wiring (144). Signals or power to drive the display device (110) can be supplied from the FPC (141) through the wiring (144).

[0040] Additionally, FIG. 1 illustrates an example in which an IC (114) is mounted on an FPC (141) in a COF manner. As for the IC (114), an IC that functions as a scan line driving circuit or a signal line driving circuit, for example, can be applied. Furthermore, in cases where the display device (110) has a circuit that functions as a scan line driving circuit and a signal line driving circuit, or where a circuit that functions as a scan line driving circuit or a signal line driving circuit is provided externally and a signal to drive the display device (110) is input through the FPC (141), the IC (114) may not be provided.

[0041] FIG. 1 illustrates an example in which a display device (110), wiring (131), and wiring (132) are provided on the side of the first substrate (101), and a touch sensor (120) is provided on the side of the second substrate (102).

[0042] [Example of cross-sectional composition]

[0043] Figure 2 (A) illustrates an example of a cross-sectional configuration obtained by cutting Figure 1 (A) along lines A1-A2, B1-B2, C1-C2, and D1-D2. Figure 2 (A) illustrates a cross-section of one pixel included in the display unit (111) as an example of the display unit (111).

[0044] The first substrate (101) and the second substrate (102) are bonded together by a first adhesive layer (151). The first adhesive layer (151) may also be provided between the light-emitting element (180) and the color filter (184).

[0045] The thickness of the first substrate (101) and the second substrate (102) having flexibility is preferably, for example, 1 μm or more and 200 μm or less, preferably 3 μm or more and 100 μm or less, more preferably 5 μm or more and 50 μm or less, and typically about 20 μm. If the thickness is less than 1 μm, the mechanical strength of the touch panel (100) is insufficient and becomes a cause of breakage. In addition, if the thickness is thicker than 200 μm, not only is flexibility reduced, but the bending stress generated when bent increases, and there is a risk that the substrate itself or wiring or components provided on the substrate may be damaged.

[0046] Additionally, it is preferable that the thicknesses of the first substrate (101) and the second substrate (102) be the same or substantially the same. By making the thicknesses of the first substrate (101) and the second substrate (102) the same, the display device (110) and touch sensor (120) provided thereon can be placed in the center of the touch panel. As a result, since the effect of bending stress generated when the touch panel is bent on the display device (110) or touch sensor (120) is suppressed, a highly reliable touch panel (100) with suppressed defects such as damage due to bending can be realized. For example, it is preferable that the thickness of the thinner side among the first substrate (101) and the second substrate (102) be 80% or more, preferably 90% or more, and more preferably 95% or more of the thickness of the thicker side.

[0047] In addition, it is preferable that the materials used for the first substrate (101) and the second substrate (102) have the same or substantially the same linear thermal expansion coefficient. By making their linear thermal expansion coefficients the same, the touch panel (100) can be suppressed from unintended bending even when the heat applied during the manufacturing process or the temperature during use changes. In addition, the temperature range in which stable operation of the touch panel is guaranteed can be expanded. It is preferable that the difference between the linear thermal expansion coefficient of the material used for the first substrate (101) and the linear thermal expansion coefficient of the material used for the second substrate (102) is, for example, 10 ppm / K or less, preferably 5 ppm / K or less, and more preferably 2 ppm / K or less in the range of 0°C to 200°C.

[0048] Figure 2 (A) illustrates transistors (161) and (162) included in a driving circuit (112), and transistors (163) and (164) included in a pixel of a display unit (111). Each transistor is provided on a first insulating layer (171).

[0049] (A) of FIGS. 1 and 2 illustrates the configuration of a driver-integrated display device in which a driving circuit (112) is formed on a first insulating layer (171) on which a display portion (111) is formed, but one or both of a circuit functioning as a scan line driving circuit and a circuit functioning as a signal line driving circuit may be provided on a surface different from the insulating surface on which the display portion (111) is formed. For example, an IC for the driving circuit may be mounted in the COG method, or a flexible printed circuit (FPC) on which an IC for the driving circuit is mounted in the COF method may be mounted.

[0050] Figure 2 (A) shows a bottom-gate type transistor as an example of a transistor provided to a driving circuit (112) and a display unit (111).

[0051] Here, it is preferable to apply an oxide semiconductor to the semiconductor layer in which a channel is formed as a transistor used in the pixel or driving circuit (112) of the display unit (111) provided to the display device (110). In particular, it is preferable to apply an oxide semiconductor with a wider band gap than silicon. It is preferable to use a semiconductor material with a wider band gap and lower carrier density than silicon, as this allows for a reduction in current when the transistor is in the off state.

[0052] For example, it is preferable that the semiconductor layer comprises at least indium (In) or zinc (Zn) as the oxide semiconductor. Furthermore, it is more preferable that the oxide semiconductor comprises an oxide denoted as an In-M-Zn-based oxide (where M represents a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0053] In particular, as a semiconductor layer, it is preferable to use an oxide semiconductor film having a plurality of crystal portions, wherein the c-axis of the crystal portions is oriented perpendicularly to the surface to be formed of the semiconductor layer or the upper surface of the semiconductor layer, and there are no grain boundaries between adjacent crystal portions.

[0054] Since such oxide semiconductors do not have crystal grain boundaries, cracks in the oxide semiconductor film are suppressed due to stress when the display panel is bent. Therefore, such oxide semiconductors can be preferably used in display panels that are flexible and can be bent.

[0055] By using such a material in the semiconductor layer, fluctuations in electrical characteristics are suppressed, enabling the realization of a highly reliable transistor.

[0056] Furthermore, transistors using oxide semiconductors in the semiconductor layer exhibit low leakage current (off-current) between the source and drain during the off state, allowing the charge accumulated in the capacitive element through the transistor to be retained for an extended period. By applying such transistors to pixels, it becomes possible to stop the driving circuit while maintaining the gradation of the image displayed in each display area. As a result, electronic devices with reduced power consumption can be realized.

[0057] In addition, a preferred form of an oxide semiconductor that can be applied to a semiconductor layer and a method of forming the same will be explained in detail in subsequent embodiments.

[0058] In addition, the operation of the touch sensor (120) during the period when the operation of the pixel is stopped is not affected by noise generated by the operation of the pixel, so the detection sensitivity of the touch sensor (120) is increased, which is desirable. Also, since the effect of noise can be eliminated in this way, the distance between the touch sensor and the display unit (111) or the driving circuit (112) can be made very short. Specifically, the gap between the first substrate (101) and the second substrate (102) can be narrowed to the extent that an area is created in which the thickness of the adhesive layer (151) is 50 nm or more and 10 μm or less, preferably 50 nm or more and 5 μm or less, and more preferably 100 nm or more and 3 μm or less, in the area where the light-emitting element (180) and the color filter (184) overlap.

[0059] In addition, examples of driving methods for the touch sensor (120) and the display device (110) will be described in subsequent embodiments.

[0060] Alternatively, a transistor using silicon in the semiconductor layer where the channel is formed may be used as a pixel or a transistor used in each driving circuit provided in each display area of ​​the display device (110). Amorphous silicon may be used as silicon, but it is particularly preferable to use silicon having crystallinity. For example, it is preferable to use microcrystalline silicon, polycrystalline silicon, or single-crystal silicon. In particular, polycrystalline silicon can be formed at a lower temperature than single-crystal silicon, and has higher field-effect mobility and reliability than amorphous silicon. By applying such a polycrystalline semiconductor to the pixel, the aperture ratio of the pixel can be improved. In addition, even when pixels are arranged at a very high density, the gate driving circuit and the source driving circuit can be formed on the same substrate as the pixel, thereby reducing the number of components constituting the electronic device.

[0061] Additionally, transistors (161) and (162) may have a second gate as shown in (A) of FIG. 2. For example, the second gate of transistor (161) may be electrically connected to the gate of transistor (161), and different potentials may be supplied to these gates. Additionally, if necessary, a second gate may also be provided to transistor (163) or transistor (164). Additionally, if not necessary, a second gate may not be provided to transistors (161) and transistor (162).

[0062] For the gate, source, and drain of a transistor, or for various wiring and electrodes constituting a touch panel, a single metal composed of aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or an alloy having any of these as a main component, can be used in a single-layer or multilayer structure. In addition, there are single-layer structures of an aluminum film containing silicon, two-layer structures in which an aluminum film is laminated on a titanium film, two-layer structures in which an aluminum film is laminated on a tungsten film, two-layer structures in which a copper film is laminated on a copper-magnesium-aluminum alloy film, two-layer structures in which a copper film is laminated on a titanium film, two-layer structures in which a copper film is laminated on a tungsten film, three-layer structures in which an aluminum film or a copper film is laminated on a titanium film or a titanium nitride film and a titanium film or titanium nitride film is formed thereon, and three-layer structures in which an aluminum film or a copper film is laminated on a molybdenum film or a molybdenum nitride film and a molybdenum film or molybdenum nitride film is formed thereon. Furthermore, transparent conductive materials containing indium oxide, tin oxide, or zinc oxide may also be used. Additionally, using copper containing manganese is preferable because it increases the controllability of formation by etching.

[0063] A pixel within the display unit (111) includes a switching transistor (163), a current control transistor (164), and a first electrode (181) electrically connected to one electrode (source electrode or drain electrode) of the transistor (164) and provided on an insulating layer (176). Additionally, an insulating layer (175) covering the end of the first electrode (181) is provided.

[0064] Here, the structure of the transistors having the display unit (111), driving circuit (112), etc. is not limited to those described above. For example, it may be a staggered type transistor or a reverse staggered type transistor. In addition, it may be a top gate type transistor or a bottom gate type transistor.

[0065] FIG. 3 illustrates a case in which a transistor with a channel-protected bottom gate structure is provided as transistor (161), transistor (162), transistor (163), and transistor (164). A protective layer is provided covering the upper surface of the semiconductor layer of the transistor, and the semiconductor layer and the source electrode or drain electrode are electrically connected through an opening formed in the protective layer. By configuring it in this way, the semiconductor layer can be suppressed from becoming thin during etching to form the source electrode and drain electrode.

[0066] Additionally, FIG. 4 illustrates a case where a top-gate structure transistor is provided as transistor (161), transistor (162), transistor (163), and transistor (164).

[0067] When using an oxide semiconductor in the semiconductor layer of a transistor, it is preferable to use a bottom gate structure. Since oxide semiconductors, which have higher mobility than amorphous silicon, can be formed at a low temperature, the heat resistance of the gate electrode located below the semiconductor layer is not a concern. Therefore, the range of material choices for the gate electrode is widened. In addition, by using a bottom gate structure, the fabrication process is simplified compared to the case of a top gate structure, thereby reducing manufacturing costs.

[0068] In particular, by using the CAAC-OS described below as an oxide semiconductor, the resistance of the oxide semiconductor to etching for forming source and drain electrodes can be increased. Therefore, it is desirable to use CAAC-OS, especially in the semiconductor layer, as it allows for the application of a channel-etched structure and further simplifies the fabrication process.

[0069] In addition, when using polycrystalline silicon or single-crystal silicon formed by transferring onto an insulating layer for the semiconductor layer of the transistor, it is preferable to use a top-gate structure. By using a top-gate structure transistor, materials with low heat resistance can be used for the wiring or electrodes on the semiconductor layer, thereby expanding the range of material selection. Furthermore, when using materials with high heat resistance for the gate electrode or when forming polycrystalline silicon at a very low temperature (e.g., less than 450°C), using the aforementioned bottom-gate structure is preferable because it can reduce the manufacturing process.

[0070] The light-emitting element (180) includes a first electrode (181), a second electrode (183), and an EL layer (182) between them. The light-emitting element (180) will be described below.

[0071] The electrode provided on the side where light is emitted from the light-emitting element (180) uses a material that is transparent to light emission from the EL layer (182).

[0072] As a transparent material, in addition to the aforementioned conductive oxides or graphene, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, or alloy materials containing these metallic materials may be used. Alternatively, nitrides of the aforementioned metallic materials (e.g., titanium nitride) may be used. Furthermore, when using metallic materials or alloy materials (or their nitrides), it is preferable to make them thin enough to be transparent. Additionally, a laminated film of the aforementioned materials may be used as a conductive layer. For example, using a laminated film of an alloy of silver and magnesium and indium tin oxide is preferable because it can increase conductivity.

[0073] Such electrodes are formed by deposition or sputtering methods. In addition, they can be formed by extrusion methods such as inkjet printing, printing methods such as screen printing, or plating methods.

[0074] In addition, when the above-described conductive oxide having light transmittance is formed by a sputtering method, the light transmittance can be improved by forming the conductive oxide under an atmosphere containing argon and oxygen.

[0075] In addition, when forming a conductive oxide film on the EL layer (182), it is preferable to form the conductive oxide film as a laminate of a first conductive oxide film formed in an atmosphere containing argon and reduced oxygen concentration, and a second conductive oxide film formed in an atmosphere containing argon and oxygen, so that film damage to the EL layer (182) can be reduced. In particular, it is preferable that the purity of the argon gas used when forming the first conductive oxide film is high, and for example, it is preferable to use an argon gas with a dew point of -70°C or lower, preferably -100°C or lower.

[0076] For the electrode provided on the side opposite to the side where light is emitted, a material having reflectivity to the light is used.

[0077] As a material having light reflectivity, metal materials such as aluminum, gold, platinum, silver, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or alloy materials containing these metal materials may be used. In addition, lanthanum, neodymium, germanium, etc., may be added to such metal materials or alloy materials. Examples of alloy materials include aluminum-containing alloys (aluminum alloys), such as aluminum-titanium alloys, aluminum-nickel alloys, or aluminum-neodymium alloys, and silver-containing alloys, such as silver-copper alloys, silver-palladium-copper alloys, or silver-magnesium alloys. Alloys containing silver and copper are preferred because they have high heat resistance. In addition, oxidation of the aluminum-containing film can be suppressed by laminating a metal film or a metal oxide film in contact with the aluminum-containing film. Examples of metal materials or metal oxide materials provided in contact with a film containing aluminum include titanium and titanium oxide. Additionally, a film made of the above-mentioned transparent material and a film made of the metal material may be laminated. For example, a laminated film of silver and indium tin oxide, a laminated film of an alloy of silver and magnesium and indium tin oxide, etc. may be used.

[0078] Such electrodes are formed by deposition or sputtering methods. In addition, they can be formed by extrusion methods such as inkjet printing, printing methods such as screen printing, or plating methods.

[0079] The EL layer (182) may include at least a layer containing a luminescent organic compound (hereinafter also referred to as a luminescent layer), and may be composed of a single layer or may be composed of multiple layers stacked. As an example of a configuration in which multiple layers are stacked, a configuration in which a hole injection layer, a hole transport layer, a luminescent layer, an electron transport layer, and an electron injection layer are stacked from the anode side may be provided. In addition, it is not necessary to provide all of these layers, excluding the luminescent layer, within the EL layer (182). In addition, these layers may be provided in overlap. Specifically, multiple luminescent layers may be provided in overlap within the EL layer (182). In addition, other configurations, such as a charge generation region, may be appropriately added. In addition, for example, it may be configured to stack multiple luminescent layers that exhibit different luminescent colors. For example, white luminescence can be obtained by stacking two or more luminescent layers that exhibit luminescent colors in a complementary relationship.

[0080] The EL layer (182) can be formed using vacuum deposition, or an extrusion method such as inkjet or dispenser method, a coating method such as spin coat method, or a printing method.

[0081] In this embodiment, a reflective material is used for the first electrode (181), and a transparent material is used for the second electrode (183). Accordingly, the light-emitting element (180) is a top-emission light-emitting element, and light is emitted toward the second substrate (102).

[0082] The above description is an explanation of the light-emitting element (180).

[0083] A second electrode (122) constituting the touch sensor (120) is formed by contacting the second insulating layer (172). Additionally, a dielectric layer (123) is provided covering the second insulating layer (172), and a first electrode (121) is provided interposed with the second electrode (122) through the dielectric layer (123).

[0084] The first electrode (121) and the second electrode (122) may use a conductive material having the light-transmitting properties described above.

[0085] A first electrode (121) and a second electrode (122) can be formed by depositing a transparent conductive material onto an insulating layer (172) by sputtering, and then removing unnecessary parts using various patterning techniques such as photolithography. Graphene may be formed by CVD, or by applying a solution in which graphene oxide is dispersed and then reducing it.

[0086] As for the material of the dielectric layer (123), in addition to resins such as acrylic and epoxy and resins having siloxane bonds, inorganic insulating materials such as silicon oxide, silicon nitride oxide, and aluminum oxide may also be used.

[0087] Additionally, an insulating layer (125) is provided to cover the first electrode (121), dielectric layer (123), and second electrode (122) constituting the touch sensor (120). The insulating layer (125) functions as a flattening layer to cover the step difference of the touch sensor (120) and to make the thickness of the color filter (184) uniform.

[0088] In addition, the insulating layer (125) also has the function of mitigating parasitic capacitance formed between the wiring or electrode constituting the touch sensor (120) and the wiring or electrode included in the display device (110). It is preferable to use an organic material with a low dielectric constant for the insulating layer (125). In addition, it is preferable to make the thickness of the insulating layer (125) for example 1 μm or more and 20 μm or less, preferably 1 μm or more and 10 μm or less, so that the thinning of the touch panel (100) and the mitigation of parasitic capacitance can be realized simultaneously.

[0089] A color filter (184) is formed in the region overlapping with the light-emitting element (180) on the insulating layer (125).

[0090] A color filter (184) is provided for the purpose of increasing color purity by adjusting the color of the light emitted from the pixel. For example, if a white light-emitting element is provided as the light-emitting element (180), full color display is possible by using multiple pixels provided with different color filters. In this case, three color filters of red (R), green (G), and blue (B) may be used, or four colors may be used by adding yellow (Y). In addition, four colors (or five colors) may be made by using a white (W) pixel in addition to R, G, B (and Y).

[0091] Additionally, a black matrix (185) is provided between adjacent color filters (184). The black matrix (185) blocks light entering between adjacent pixels to suppress color mixing between adjacent pixels. The black matrix (185) may be placed only between adjacent pixels with different light emission colors and may not be provided between pixels with the same light emission color. Here, light leakage can be suppressed by providing the ends of the color filters (184) to overlap with the black matrix (185). The black matrix (185) may use a light-blocking material and may be formed using a metal material or a resin material containing a pigment. Furthermore, as shown in (A) of FIG. 2, it is preferable to provide the black matrix (185) in an area other than the display unit (111), such as the driving circuit (112), so that unintended light leakage caused by waveguide light can be suppressed.

[0092] As shown in (A) of FIG. 2, it is preferable to have a configuration in which a first electrode (121) and a second electrode (122) constituting a touch sensor (120) are placed on the side of the second substrate (102), and a color filter (184) is placed on the side closer to the light-emitting element (180). In this configuration, the sensitivity of the touch sensor (120) is improved because the distance between the touch sensor (120) and the touch surface is close. In addition, by making the distance between the color filter (184) and the light-emitting element (180) close, the light from the light-emitting element (180) can be suppressed from passing through the color filter (184) of an adjacent pixel.

[0093] It is preferable to use a material that inhibits the diffusion of impurities from the outside in the insulating layer (171) and the insulating layer (172). For example, it is preferable to use an inorganic insulating material such as a semiconductor oxide, nitride, silicon nitride, silicon nitride, or silicon nitride, or a metal oxide, metal nitride, or metal nitride, such as aluminum oxide, aluminum nitride, or aluminum nitride. Alternatively, a laminate of such inorganic insulating material, or a laminate of an inorganic insulating material and an organic insulating material may be used.

[0094] A wiring (132) is provided on the insulating layer (171). An insulating layer (176) and a conductive layer (166) are provided on the wiring (132). The conductive layer (166) is electrically connected to the wiring (132) through an opening formed in the insulating layer (176). Here, Figure 2 (A) illustrates an example in which the wiring (132) is formed by processing a conductive film identical to the source electrode and drain electrode of a transistor, and the conductive layer (166) is formed by processing a conductive film identical to the first electrode (181) of a light-emitting element (180). Additionally, it is preferable that the wiring (131) in Figure 1 also have the same configuration as the wiring (132).

[0095] Additionally, on the side of the second substrate (102), the electrode (121) of the touch sensor (120) is provided extending to an area overlapping with the conductive layer (166), and the upper surface (the surface facing the conductive layer (166)) includes a portion where no structure other than the adhesive layer is provided. Also, although not shown in the drawing, the same applies to the electrode (122).

[0096] The electrode (121) of the touch sensor (120) and the conductive layer (166) are electrically connected through conductive particles (165). The conductive particles (165) are provided to be dispersed within the adhesive layer (151). Thus, the electrode (121) and the wiring (132) are electrically connected through the conductive particles (165) and the conductive layer (166). In addition, the electrode (122) and the wiring (131) in FIG. 1 are also electrically connected through the conductive particles (165).

[0097] As for the conductive particles (165), it is preferable to use particles whose surface, such as organic resin or silica, is coated with a conductive material such as a metal material or an alloy material. It is preferable to use nickel or gold as the metal material because it can reduce contact resistance. In addition, it is preferable to use particles coated in layers of two or more types of metal materials, such as nickel being coated with gold. Alternatively, particles of a conductive material may be used as the conductive particles (165).

[0098] It is preferable that the conductive particle (165) provided between the electrode (121) and the conductive layer (166) be deformed into a compressed shape by pressure applied from the vertical direction. With such a configuration, the contact area between the conductive particle (165) and the electrode (121) (or electrode (122)) or the conductive layer (166) is increased, thereby reducing the electrical resistance in their connection. Additionally, in the schematic cross-sectional view shown in FIG. 2 (A), for convenience, the cross-sectional shape of the conductive particle (165) is depicted as an ellipse with a major axis in a direction perpendicular to the substrate; however, in reality, in many cases, the cross-sectional shape is circular or an ellipse with a major axis component in a direction parallel to the substrate. FIG. 2 (B) illustrates an example where the cross-section of the conductive particle (165) is an ellipse with a major axis component in a direction parallel to the substrate.

[0099] A portion of the wiring (132) at the outer edge of the substrate (101) forms a connection terminal (156). Figure 2 (A) illustrates a case where the connection terminal (156) is formed as a stacked structure of a conductive layer obtained by processing a portion of the wiring (132) and a conductive film identical to the gate electrode of a transistor. By forming the connection terminal (156) as a stacked structure consisting of multiple layers in this way, the mechanical strength when compressing the FPC (143) can be increased. The connection terminal (156) and the FPC (143) are electrically connected through a connection layer (157). An anisotropic conductive film (ACF) or anisotropic conductive paste (ACP) can be used as the connection layer (157).

[0100] Additionally, wiring (144) electrically connected to the display unit (111) or the driving circuit (112) extends to another outer periphery of the substrate (101). Furthermore, a portion of the wiring (144) at the outer periphery of the substrate (101) forms a portion of the connection terminal (155). The connection terminal (155) can be configured in the same way as the connection terminal (156) described above. The connection terminal (155) is electrically connected to the FPC (141) through the connection layer (158).

[0101] Here, the first substrate (101) and the insulating layer (171) are bonded together by an adhesive layer (152). Additionally, the second substrate (102) and the insulating layer (172) are bonded together by an adhesive layer (153).

[0102] The adhesive layer (152) and the adhesive layer (153) may use the same material as the adhesive layer (151). For each adhesive layer, a curable resin such as a thermosetting resin, a photosetting resin, or a two-component type curable resin may be used. For example, a resin such as an acrylic resin, a urethane resin, an epoxy resin, or a resin having siloxane bonds may be used.

[0103] Here, it is preferable to use the same material for at least two, preferably all, of the adhesive layer (151), adhesive layer (152), and adhesive layer (153). By using the same material for these adhesive layers, the coefficient of linear thermal expansion can be made the same, thereby preventing the touch panel (100) from unintentionally bending even when the heat applied during the manufacturing process or the temperature during use changes. In addition, the temperature range in which stable operation of the touch panel is guaranteed can be expanded.

[0104] In addition, it is preferable that at least two of the adhesive layer (151), adhesive layer (152), and adhesive layer (153), preferably all of them, have substantially the same thickness. For example, it is preferable that the thickness of the thinner of the two adhesive layers be at least 50%, preferably at least 80%, and more preferably at least 90% of the thickness of the thicker of the two adhesive layers.

[0105] The adhesive layer (152) and the adhesive layer (153), like the adhesive layer (151), are preferably thin enough to have a thickness of 50 nm or more and 10 μm or less, preferably 50 nm or more and 5 μm or less, and more preferably 100 nm or more and 3 μm or less. By making the thickness of these three adhesive layers thin, the touch panel (100) can be made thin, thereby enabling the realization of a touch panel with excellent flexibility.

[0106] Here, it is not necessary to provide either one or both of the adhesive layer (152) and the adhesive layer (153). FIG. 5 illustrates a case where neither the adhesive layer (152) nor the adhesive layer (153) is provided. In FIG. 5, an insulating layer (171) is provided to contact the upper surface of a first substrate (101) having flexibility, and an insulating layer (172) is provided to contact the upper surface of a second substrate (102). Furthermore, although a configuration without the adhesive layer (152) and the adhesive layer (153) is shown here, unlike the configuration shown in FIG. 2 (A), FIG. 3, FIG. 4, etc., it is also possible to have a configuration where neither one or both of the adhesive layer (152) and the adhesive layer (153) are provided.

[0107] It is preferable that a protective layer (178) be provided on the surface of the substrate (102). The protective layer (178) may be called a ceramic coat and has the function of protecting the surface of the substrate (102) when the touch panel (100) is operated with a finger or a stylus. For example, inorganic insulating materials such as silicon oxide, aluminum oxide, yttrium oxide, and yttria-stabilized zirconia (YSZ) may be used for the protective layer (178). The protective layer (178) can be formed by a sputtering method or a sol-gel method. In particular, it is preferable to form the protective layer (178) by the aerosol deposition method described later, as this allows for the formation of a film with high density and increases mechanical strength.

[0108] Here, we explain how to manufacture a flexible touch panel.

[0109] For convenience, a configuration including pixels or driving circuits, a configuration including optical components such as color filters, or a configuration including touch sensors will be referred to as a device layer. The device layer may, for example, include a display element, and in addition to the display element, may also include wiring electrically connected to the display element, and components such as transistors used in pixels or circuits.

[0110] In addition, the support having an insulating surface on which the device layer is formed is referred to as the base material.

[0111] As a method for forming a device layer on a substrate having a flexible insulating surface, there is a method of directly forming the device layer on the substrate, and a method of forming the device layer on a rigid supporting substrate used separately from the substrate, and then peeling off the device layer and the supporting substrate to transfer the device layer to the substrate.

[0112] If the material constituting the substrate has heat resistance to the heat applied during the device layer formation process, it is desirable to form the device layer directly on the substrate, as this simplifies the process. In this case, it is also desirable to form the device layer while the substrate is fixed to a support substrate, as this facilitates transport within and between devices.

[0113] In addition, when using a method of forming a device layer on a support substrate and then transferring it to a substrate, a release layer and an insulating layer are first laminated on the support substrate, and a device layer is formed on the insulating layer. Subsequently, the support substrate and the device layer are peeled off and transferred to a substrate. At this time, it is preferable to select a material in which peeling occurs at the interface between the support substrate and the release layer, at the interface between the release layer and the insulating layer, or within the release layer.

[0114] For example, it is preferable to laminate a layer containing a high-melting-point metal material such as tungsten as a release layer and a layer containing an oxide of said metal material, and to use a layer in which a silicon nitride layer or a silicon oxynitride layer is laminated multiple times as an insulating layer on top of the release layer. Using a high-melting-point metal material is preferable because it increases the degree of freedom in the process of forming the device layer.

[0115] Delamination may be performed by applying mechanical force, etching the delamination layer, or dropping liquid onto a part of the delamination interface to penetrate the liquid into the entire delamination interface. Alternatively, delamination may be performed by applying heat to the delamination interface and utilizing the difference in the coefficient of thermal expansion.

[0116] In addition, if peeling is possible at the interface between the support substrate and the insulating layer, a release layer may not be provided. For example, glass may be used as the support substrate and an organic resin such as polyimide may be used as the insulating layer, and a peeling initiation point may be formed by locally heating a portion of the organic resin with laser light or the like, thereby performing peeling at the interface between the glass and the insulating layer. Alternatively, a metal layer may be provided between the support substrate and the insulating layer made of an organic resin, and peeling may be performed at the interface between the metal layer and the insulating layer by heating the metal layer by passing an electric current through it. In this case, the insulating layer made of an organic resin may be used as the substrate.

[0117] Examples of flexible substrates include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin, cycloolefin resin, polystyrene resin, polyimide resin, and polyvinyl chloride resin. In particular, it is desirable to use a material with a low linear thermal expansion coefficient, and for example, polyimide resin, polyimide resin, PET, etc., with a linear thermal expansion coefficient of 30 ppm / K or less can be preferably used. In addition, a substrate (also called prepreg) in which a resin is impregnated into a fiber body, or a substrate in which an inorganic filler is mixed with an organic resin to lower the linear thermal expansion coefficient, may also be used.

[0118] When using a material containing fibers, the fibers are high-strength fibers made of organic or inorganic compounds. Specifically, high-strength fibers refer to fibers with a high tensile modulus of elasticity or Young's modulus; representative examples include polyvinyl alcohol fibers, polyester fibers, polyamide fibers, polyethylene fibers, aramid fibers, polyparaphenylenebenzobisoxazole fibers, glass fibers, or carbon fibers. Examples of glass fibers include E-glass, S-glass, D-glass, Q-glass, etc. These may be used in a woven or non-woven state, and a structure formed by impregnating the fibers with resin and curing the resin may be used as a flexible substrate. Using a structure composed of fibers and resin as a flexible substrate is desirable because it improves reliability against breakage caused by bending or localized pressure.

[0119] A touch panel (100) according to one embodiment of the present invention is configured to include a display device (110) and a touch sensor (120) between a pair of flexible substrates. Accordingly, the display device (110) and the touch sensor (120) can be placed in the center of the thickness direction of the touch panel (100). As a result, since the effect of bending stress generated when the touch panel (100) is bent on the display device (110) or the touch sensor (120) is suppressed, a highly reliable touch panel (100) can be realized in which defects such as damage due to bending are suppressed.

[0120] In addition, a touch panel (100) according to one embodiment of the present invention is configured such that a terminal connecting the wiring of a touch sensor (120) and an FPC is placed on the side of a substrate where a display device (110) is provided. Furthermore, by placing the terminal in an area different from the area where the driving circuit of the display device (110) is provided at the outer edge of the touch panel, the degree of freedom in the placement position of the FPC can be increased.

[0121] Additionally, the positions of the FPC (141), FPC (142), and FPC (143) are not limited to the configuration shown in FIG. 1, and may be appropriately changed according to the shape or specifications of the housing of an electronic device, such as one that carries the touch panel (100). For example, as shown in FIG. 6 (A), the FPC (142), which is electrically connected to the wiring (131), may be placed on the side where the FPC (143) is provided. Also, although FIG. 6 (A) is configured to provide the FPC (142) and FPC (143) individually, they may be replaced with a single FPC (140), as shown in FIG. 6 (B), for example. Additionally, although not shown in the drawings, the FPC (142) and FPC (143) may be placed on the side where the FPC (141) is provided on the first substrate (101).

[0122] In addition, a display device according to one embodiment of the present invention may be an active matrix method having active elements in the pixels or a passive matrix method not having active elements in the pixels.

[0123] In the active matrix method, various active devices (active devices, non-linear devices) other than transistors can be used as active components. For example, metal insulator metal (MIM) or thin film diode (TFD) may be used. Since these devices involve fewer manufacturing processes, they can reduce manufacturing costs or improve yield. Furthermore, because these devices are small, they can improve the aperture ratio, enabling lower power consumption or higher brightness.

[0124] In addition to the active matrix method, a passive matrix method that does not use active components (active components, non-linear components) may also be adopted. Since the passive matrix method does not use active components, the manufacturing process is simplified, which allows for reduced manufacturing costs or improved yield. Furthermore, because active components are not used, the aperture ratio can be improved, enabling lower power consumption or higher brightness.

[0125] [Variation Example]

[0126] The following describes a touch panel configuration that differs in some respects from the configuration described above. Additionally, explanations of parts that overlap with the above will be omitted, and only the main differences will be described.

[0127] Figure 7 (A) is a schematic cross-sectional view of a touch panel described below.

[0128] The configuration shown in (A) of FIG. 7 differs from the configuration shown in (A) of FIG. 2 in that it mainly has a bottom-emission light-emitting element and the position of the touch sensor is different.

[0129] An insulating layer (172) is provided on the first substrate (101) via an adhesive layer (192), and an electrode (121), an electrode (122), and a dielectric layer (123), etc., constituting a touch sensor (120) are provided on the insulating layer (172). Additionally, the electrode (121), the electrode (122), and the dielectric layer (123), etc., are provided below the insulating layer (171) via an adhesive layer (191). In other words, the touch panel illustrated in (A) of FIG. 7 is configured such that a touch sensor (120) is provided between a display device (110) and the first substrate (101).

[0130] Additionally, a back-emitting type light-emitting element is applied as the light-emitting element (180) shown in FIG. 7 (A). That is, light from the light-emitting element (180) is extracted toward the first substrate (101). A color filter (184) is positioned toward the first substrate (101) rather than the light-emitting element (180). FIG. 7 (A) illustrates a case where a color filter (184) is positioned between an inorganic insulating layer covering a transistor and an insulating layer (176). Additionally, a black matrix may be provided by covering the transistor or wiring.

[0131] The first substrate (101) is provided with a connection terminal (156) for connecting the electrode (121) of the touch sensor (120) and the FPC (143) (or the electrode (122) and the FPC (142)). Unlike the driving circuit (112) or the display unit (111), the connection terminal (156) does not include an adhesive layer (191) and a structure thereon, and at least a portion of the upper surface of the connection terminal (156) is exposed. As shown in FIG. 7 (A), it is preferable that the first substrate (101) extends outwardly from the second substrate (102) in the direction in which the connection terminal (156) is provided.

[0132] Additionally, it is preferable to provide an insulating layer (173) on the lower surface of the second substrate (102) (the surface on the side of the light-emitting element (180)). It is preferable to use an inorganic insulating material such as an insulating layer (171) or an insulating layer (172) for the insulating layer (173).

[0133] Since the first substrate (101) side becomes the display surface and operation surface, it is preferable to provide a protective layer (178) on the surface of the first substrate (101).

[0134] In addition, as shown in (B) of FIG. 7, the insulating layer (172) may be formed directly on the upper surface of the first substrate (101) without providing an adhesive layer (192) between the first substrate (101) and the insulating layer (172).

[0135] The adhesive layer (191) and the adhesive layer (192) may have the same composition as the adhesive layer (152) or the adhesive layer (153) described above.

[0136] In addition, the transistor or its surrounding configuration is not limited to that shown in FIG. 7, and the transistor configuration shown in FIG. 2 to FIG. 4, or a stacked structure such as the transistor structure and the insulating layer around it described above may be adopted.

[0137] The above is an explanation of the variations.

[0138] This embodiment may be implemented by appropriately combining at least a part thereof with other embodiments described in this specification.

[0139] (Embodiment 2)

[0140] In this embodiment, an example of a method for driving a touch panel according to one form of the present invention will be described with reference to the drawings.

[0141] [Example of sensor detection method]

[0142] FIG. 8 (A) is a block diagram illustrating the configuration of a mutual capacitance type touch sensor. FIG. 8 (A) illustrates a pulse voltage output circuit (501) and a current detection circuit (502). FIG. 8 (A) also illustrates an electrode (121) to which a pulse voltage is applied and an electrode (122) that detects a change in current as six wires, X1 to X6 and Y1 to Y6, respectively. FIG. 8 (A) also illustrates a capacitance element (503) formed by the superposition of the electrode (121) and the electrode (122). Additionally, the functions of the electrode (121) and the electrode (122) may be interchanged.

[0143] The pulse voltage output circuit (501) is a circuit for sequentially applying pulse voltage to the wiring (X1 to X6). When pulse voltage is applied to the wiring (X1 to X6), an electric field is generated between the electrode (121) and the electrode (122) that form the capacitance element (503). By utilizing the change in the mutual capacitance in the capacitance element (503) due to the shielding of the electric field between these electrodes, proximity or contact of the object to be tested can be detected.

[0144] The current detection circuit (502) is a circuit for detecting a change in current in the wiring (Y1~Y6) due to a change in mutual capacitance in the capacitance element (503). In the wiring (Y1~Y6), if there is no proximity or contact with the object to be tested, there is no change in the detected current value; however, if the mutual capacitance decreases due to proximity or contact with the object to be tested, the reduced current value is detected. Additionally, it is preferable to detect the current using an integration circuit or the like.

[0145] In addition, either or both of the pulse voltage output circuit (501) and the current detection circuit (502) described above in Embodiment 1 may be formed on the first substrate (101). For example, it is preferable to form the display unit (111) and the driving circuit (112) simultaneously, as this simplifies the process and reduces the number of components of the electronic device equipped with the touch panel (100). In addition, either or both of the pulse voltage output circuit (501) and the current detection circuit (502) may be mounted in a COF manner on an FPC (FPC (142) and FPC (143) (or FPC (140))) that is electrically connected to the touch sensor (120).

[0146] In particular, if crystalline silicon, such as polycrystalline silicon or single-crystal silicon, is used in the semiconductor layer where the channel is formed as a transistor formed on the first substrate (101), the driving capability of circuits such as pulse voltage output circuit (501) or current detection circuit (502) is improved, so the sensitivity of the touch sensor can be improved.

[0147] FIG. 8 (B) is a timing chart of the input / output waveforms of the mutual capacitance type touch sensor shown in FIG. 8 (A). In FIG. 8 (B), detection of the object to be detected in each matrix is ​​performed during one frame period. In addition, FIG. 8 (B) shows two cases: when the object to be detected is not detected (non-touch) and when the object to be detected is detected (touch). Also, for the wiring (Y1~Y6), the waveform of the voltage value corresponding to the detected current value is shown.

[0148] Pulse voltages are applied sequentially to the wirings (X1 to X6), and the waveforms in the wirings (Y1 to Y6) change according to these pulse voltages. When there is no proximity or contact with the object to be tested, the waveforms in the wirings (Y1 to Y6) change according to the change in voltage of the wirings (X1 to X6). On the other hand, at locations where the object to be tested is in proximity or contact, the current value decreases, so the waveform of the corresponding voltage value also changes.

[0149] In this way, proximity or contact of the subject to test can be detected by detecting changes in mutual capacity.

[0150] Additionally, (A) of FIG. 8 illustrates a passive matrix touch sensor that provides only a capacitive element (503) at the intersection of the wiring as a touch sensor, but an active matrix touch sensor having a transistor and a capacitive element may also be used. FIG. 9 illustrates an example of a sensor circuit included in an active matrix touch sensor.

[0151] The sensor circuit has a capacitance element (503), a transistor (511), a transistor (512), and a transistor (513). A signal (G2) is supplied to the gate of the transistor (513), and a voltage (VRES) is applied to one of the source and drain, while the other is electrically connected to one electrode of the capacitance element (503) and the gate of the transistor (511). One of the source and drain of the transistor (511) is electrically connected to one of the source and drain of the transistor (512), and a voltage (VSS) is applied to the other. A signal (G1) is supplied to the gate of the transistor (512), and the other of the source and drain is electrically connected to the wiring (ML). A voltage (VSS) is applied to the other electrode of the capacitance element (503).

[0152] Next, the operation of the sensor circuit is described. First, a potential that turns the transistor (513) on is supplied as a signal (G2), and a potential corresponding to the voltage (VRES) is supplied to the node (n) to which the gate of the transistor (511) is connected. Next, a potential that turns the transistor (513) off is supplied as a signal (G2), and the potential of the node (n) is maintained.

[0153] Next, as the mutual capacitance of the capacitance element (503) changes due to proximity or contact with the test body such as a finger, the potential of the node (n) changes from VRES.

[0154] During the reading operation, a potential is supplied to the signal (G1) to turn on the transistor (512). Depending on the potential of the node (n), the current flowing through the transistor (511), that is, the current flowing through the wiring (ML), changes. By detecting this current, proximity or contact of the object to be detected can be detected.

[0155] For the transistors (511), (512), and (513), it is preferable to use transistors in which an oxide semiconductor is applied to the semiconductor layer where the channel is formed. In particular, if an oxide semiconductor is applied to the semiconductor layer where the channel of the transistor (513) is formed, the potential of the node (n) can be maintained for a long period of time, thereby reducing the frequency of the operation (refresh operation) of supplying VRES to the node (n) again.

[0156] [Example of a method for driving a display device]

[0157] FIG. 10 (A) is a block diagram illustrating an example of the configuration of a display device. FIG. 10 (A) shows a gate driving circuit (GD), a source driving circuit (SD), and a pixel (pix). In FIG. 10 (A), the pixels (pix) are each assigned the symbols (1,1) to (n,m) to correspond to the gate lines (x_1 to x_m (m is a natural number)) electrically connected to the gate driving circuit (GD) and the source lines (y_1 to y_n (n is a natural number)) electrically connected to the source driving circuit (SD).

[0158] Figure 10 (B) is a timing chart of the signals supplied to the gate line and source line in the display device shown in Figure 10 (A). Figure 10 (B) is illustrated in two cases: one where the data signal is rewritten every frame period, and another where the data signal is not rewritten. Additionally, Figure 10 (B) does not take into account periods such as the retrace period.

[0159] When rewriting data signals at 1 frame intervals, scan signals are supplied sequentially to gate lines (x_1~x_m). During the horizontal scan period 1H, which is the period when the scan signal is at the H level, data signals (D) are supplied to source lines (y_1~y_n) of each column.

[0160] If the data signal is not rewritten every frame period, the supply of the scan signal to the gate lines (x_1~x_m) is stopped. Also, during the horizontal scan period 1H, the supply of the data signal to the source lines (y_1~y_n) of each column is stopped.

[0161] A driving method that does not rewrite data signals every frame period is particularly effective when an oxide semiconductor is applied to the semiconductor layer where the channel of a transistor included in a pixel is formed. A transistor with an oxide semiconductor has a very small off-current compared to a transistor with a semiconductor such as silicon. Therefore, since the data signal recorded in the previous period can be maintained without rewriting data signals every frame period, the grayscale of the pixel can be maintained for, for example, for more than 1 second, preferably more than 5 seconds.

[0162] In addition, when polycrystalline silicon is applied to the semiconductor layer where the channel of the transistor included in the pixel is formed, it is desirable to increase the retention capacity of the pixel in advance. The larger the retention capacity, the longer the pixel's gradation can be maintained. The size of the retention capacity can be set according to the leakage current of the transistor or display element electrically connected to the retention capacity, but for example, if the retention capacity per pixel is set to 5fF or more and 5pF or less, preferably 10fF or more and 5pF or less, and more preferably 20fF or more and 1pF or less, the data signal recorded in the previous period can be maintained without rewriting the data signal every frame period, so the pixel's gradation can be maintained for, for example, a period of several frames or tens of frames.

[0163] [Example of driving method for display device and touch sensor]

[0164] FIGS. 11 (A) to (D) is a diagram illustrating, as an example, the operation during a continuous frame period when the touch sensor described using FIGS. 8 (A) and (B) and the display device described using FIGS. 10 (A) and (B) are driven for 1 sec. (1 second). FIGS. 11 (A) also shows a case where the frame period of the display device is 16.7 ms (frame frequency: 60 Hz) and the frame period of the touch sensor is 16.7 ms (frame frequency: 60 Hz).

[0165] In the touch panel of the present embodiment, since the display device and the touch sensor operate independently of each other, the display period and the touch detection period can be parallel. Accordingly, as shown in (A) of FIG. 11, the frame period of both the display device and the touch sensor can be set to 16.7ms (frame frequency: 60Hz). The frame frequencies of the touch sensor and the display device may be different. For example, as shown in (B) of FIG. 11, the frame period of the display device may be set to 8.3ms (frame frequency: 120Hz) and the frame period of the touch sensor may be set to 16.7ms (frame frequency: 60Hz). Additionally, although not shown in the drawings, the frame frequency of the display device may be set to 33.3ms (frame frequency: 30Hz).

[0166] In addition, the power consumption of the display device can be suppressed by making the frame frequency of the display device switchable so that the frame frequency is high (e.g., 60Hz or higher or 120Hz or higher) when displaying video and low (e.g., 60Hz or lower, 30Hz or lower, or 1Hz or lower) when displaying still images. In addition, the frame frequency of the touch sensor can be switchable so that the frame frequency is different in standby mode and when touch is detected.

[0167] In addition, in the touch panel of the present embodiment, the data signal that was rewritten in the previous period is retained even without rewriting the data signal in the display device, so the frame period of the display device can be made longer than 16.7ms. Therefore, as shown in (C) of FIG. 11, the frame period of the display device can be set to 1 sec. (frame frequency: 1Hz), and the frame period of the touch sensor can be set to 16.7ms (frame frequency: 60Hz).

[0168] In addition, when the touch panel in the present embodiment is driven as shown in (C) of FIG. 11, the touch sensor can be continuously driven. Therefore, as shown in (D) of FIG. 11, the data signal of the display device may be re-recorded at the point when the touch sensor detects proximity or contact of the object being detected.

[0169] If the display device rewrites the data signal during the touch sensor's sensing period, noise generated when driving the display device may be transmitted to the touch sensor, potentially degrading its sensitivity. Therefore, it is particularly desirable to operate the device so that the display device's data signal rewriting and the touch sensor's sensing are performed at different times.

[0170] Figure 12 (A) illustrates an example in which the data signal of the display device is rewritten and the touch sensor is sensed alternately. Additionally, Figure 12 (B) illustrates an example in which the touch sensor senses once every two rewriting operations of the data signal of the display device. Furthermore, the configuration may be configured such that the touch sensor senses once every three or more rewriting operations, without being limited to this.

[0171] In addition, by applying an oxide semiconductor to the semiconductor layer where the channel of a transistor included in a pixel of a display device is formed, the off-current can be reduced, thereby sufficiently reducing the frequency of data signal rewriting. Specifically, a sufficiently long rest period can be set between rewriting a data signal and rewriting the next data signal. The rest period can be, for example, 0.5 seconds or more, 1 second or more, or 5 seconds or more. The upper limit of the rest period is limited by the leakage current of the capacitive element or display element connected to the transistor, but can be, for example, 1 minute or less, 10 minutes or less, 1 hour or less, or 1 day or less.

[0172] Figure 12 (C) illustrates an example of rewriting the data signal of a display device at a frequency of once every 5 seconds. In Figure 12 (C), a rest period is set during which operation is suspended between rewriting the data signal of the display device and rewriting the data signal next. During the rest period, the touch sensor can be driven at a frame frequency of i Hz (where i is greater than or equal to the frame frequency of the display device, specifically 0.2 Hz or higher). Furthermore, as shown in Figure 12 (C), it is desirable to perform sensing by the touch sensor during the rest period and not during the rewriting period of the data signal of the display device, as this can improve the sensitivity of the touch sensor. Additionally, as shown in Figure 12 (D), rewriting the data signal of the display device and sensing by the touch sensor simultaneously can simplify the signal for driving.

[0173] In addition, during the idle period when the data signal rewrite operation of the display device is not performed, it is sufficient to stop only the supply of the signal to the driving circuit, and further reduce power consumption by also stopping the supply of the power potential.

[0174] As described in Embodiment 1, a touch panel according to one embodiment of the present invention has a configuration in which a display device and a touch sensor are provided between two flexible substrates, and the distance between the display device and the touch sensor can be made very short. In this case, noise during the operation of the display device is likely to spread to the touch sensor, and there is a risk that the sensitivity of the touch sensor may be reduced, but by applying the driving method described as an example in this embodiment, a touch panel that achieves both thinness and high detection sensitivity can be realized.

[0175] (Embodiment 3)

[0176] In this embodiment, an example of the configuration of a touch panel and a driving method according to one form of the present invention will be described with reference to the drawings.

[0177] [Composition of the touch panel]

[0178] FIG. 13 is a block diagram illustrating an example configuration of a touch panel described below. As shown in FIG. 13, the touch panel (80) includes a display device (800), a control circuit (810), a counter circuit (820), and a touch sensor (850).

[0179] A video signal, which is digital data, and a synchronization signal (SYNC) for controlling the rewriting of the screen of the display device (800) are input to the touch panel (80). Examples of synchronization signals include a horizontal synchronization signal (Hsync), a vertical synchronization signal (Vsync), and a reference clock signal (CLK).

[0180] The display device (800) has a display unit (801), a gate driver (802), and a source driver (803). The display unit (801) has a plurality of pixels (PIX). Pixels (PIX) in the same row are connected to the gate driver (802) by a common gate line (L_X), and pixels (PIX) in the same column are connected to the source driver (803) by a common source line (L_Y).

[0181] High level potential (VH), low level potential (VL), and high power potential (VDD) and low power potential (VSS) are supplied to the display device (800). The high level potential (VH) is supplied to each pixel (PIX) of the display unit (801) through wiring (L_H). Additionally, the low level potential (VL) is supplied to each pixel (PIX) of the display unit (801) through wiring (L_L).

[0182] The source driver (803) processes the input image signal to generate a data signal and outputs the data signal to the source line (L_Y). The gate driver (802) outputs a scan signal to the gate line (L_X) for selecting the pixel (PIX) where the data signal is recorded.

[0183] The pixel (PIX) has a switching element whose electrical connection with the source line (L_Y) is controlled by a scan signal. When the switching element is turned on, a data signal is written to the pixel (PIX) through the source line (L_Y).

[0184] The control circuit (810) is a circuit that controls the entire touch panel (80) and has a circuit that generates control signals for the circuits constituting the touch panel (80).

[0185] The control circuit (810) has a control signal generating circuit that generates control signals for the gate driver (802) and the source driver (803) based on a synchronization signal (SYNC). As control signals for the gate driver (802), there are a start pulse (GSP), a clock signal (GCLK), etc., and as control signals for the source driver (803), there are a start pulse (SSP), a clock signal (SCLK), etc. For example, the control circuit (810) generates multiple clock signals with the same period and a phase shifted as clock signals (GCLK, SCLK).

[0186] Additionally, the control circuit (810) controls the output of a video signal input from outside the touch panel (80) to the source driver (803).

[0187] Additionally, a sensor signal (S_touch) from a touch sensor (850) is input to the control circuit (810). The control circuit (810) corrects the image signal according to the sensor signal. Although the correction of the image signal varies depending on the sensor signal, image processing based on the touch is performed.

[0188] The source driver (803) has a digital / analog conversion circuit (804) (hereinafter referred to as the DA conversion circuit (804)). The DA conversion circuit (804) converts an image signal into an analog signal to generate a data signal.

[0189] In addition, if the image signal input to the touch panel (80) is an analog signal, the control circuit (810) converts it into a digital signal and outputs it to the display device (800).

[0190] The image signal is image data of each frame. The control circuit (810) has the function of processing the image data and controlling the output of the image signal to the source driver (803) based on the information obtained from the processing. Accordingly, the control circuit (810) has a motion detection unit (811) that processes the image data and detects motion from the image data of each frame. In addition, when a sensor signal is input, the image signal according to the image data is corrected according to the sensor signal.

[0191] When the motion detection unit (811) determines that there is movement, the control circuit (810) continues to output the image signal to the source driver (803). Conversely, when it determines that there is no movement, the control circuit (810) stops outputting the image signal to the source driver (803). Additionally, when it determines that there is movement again, it resumes outputting the image signal.

[0192] The control circuit (810) can control the display of the display unit (801) by switching between a first mode for displaying an image with motion (video display) and a second mode for displaying an image without motion (still image display) based on the determination of the motion detection unit (811). The first mode is, for example, a mode in which the frame frequency becomes 60Hz or higher when the vertical synchronization signal (Vsync) is 60Hz. Additionally, the second mode is, for example, a mode in which the frame frequency becomes less than 60Hz when the vertical synchronization signal (Vsync) is 60Hz.

[0193] In the second mode, it is preferable to pre-set the frame frequency according to the voltage maintenance characteristics of the pixel. For example, when the motion detection unit (811) determines that there is no movement for a certain period and stops the output of the image signal to the source driver (803), the voltage corresponding to the gradation of the image signal recorded in the pixel (PIX) decreases. Therefore, it is preferable to record (also called refresh) the voltage corresponding to the gradation of the image signal of the same image at each cycle of the frame frequency. As for the timing of this refresh (also called the refresh rate), it is preferable to configure it to be performed at regular intervals based on the signal obtained by counting the H level of the vertical synchronization signal (Vsync) in the counter circuit (820).

[0194] In the case where the refresh rate in the counter circuit (820) is set to once every second, if the frequency of the vertical synchronization signal (Vsync) is 60Hz, it is preferable to perform the refresh based on the count signal (Count) obtained by counting the H level of the vertical synchronization signal (Vsync) 60 times. In the case where the refresh rate is set to once every 5 seconds, if the frequency of the vertical synchronization signal (Vsync) is 60Hz, it is preferable to perform the refresh based on the count signal (Count) obtained by counting the H level of the vertical synchronization signal (Vsync) 300 times. Additionally, the counter circuit (820) may be configured to forcibly switch from the second mode to the first mode according to the sensor signal when a sensor signal is input from the touch sensor (850).

[0195] In addition, there are no special restrictions on image processing for motion detection in the motion detection unit (811). For example, as a motion detection method, there is a method of obtaining difference data from image data between two consecutive frames. It is possible to determine whether there is motion from the obtained difference data. There is also a method of detecting a motion vector.

[0196] The touch sensor (850) may have the operation and structure described in the above-described embodiment applied to it.

[0197] In this embodiment, since the display device and the touch sensor (850) can operate independently of each other, a touch detection period can be set in parallel with the display period. Therefore, even in the case of a configuration where the control circuit (810) switches to a first mode or a second mode, the operation of the touch sensor can be controlled independently. In addition, by synchronizing the operation of the display device (800) and the touch sensor (850) so that the data signal rewriting operation of the display device (800) and the sensing operation of the touch sensor (850) are performed at different times, the sensing sensitivity can be increased.

[0198] [Example of pixel composition]

[0199] Figure 14 (A) is a circuit diagram illustrating an example configuration of a pixel (PIX). The pixel (PIX) has a transistor (TR1), a transistor (TR2), a light-emitting element (EL), and a capacitance element (CAP).

[0200] The transistor (TR1) functions as a switching element that controls the electrical connection between the source line (L_Y) and the gate of the transistor (TR2), and its on and off states are controlled by a scan signal input to the gate of the transistor (TR1). The transistor (TR2) functions as a switching element for controlling the current flowing through the light-emitting element (EL).

[0201] In addition, it is preferable to apply an oxide semiconductor or polycrystalline silicon to the semiconductor layer where the channels of the transistor (TR1) and transistor (TR2) are formed.

[0202] The light-emitting element (EL) includes an EL layer containing a light-emitting organic compound between two electrodes. The luminous brightness of the light-emitting element changes according to the current flowing between the two electrodes. A low-level potential is applied to one electrode of the light-emitting element from wiring (L_L), and a high-level potential is applied to the other electrode from wiring (L_H) through a transistor (TR2).

[0203] The capacitance element (CAP) has the function of maintaining the potential of the gate of the transistor (TR2).

[0204] Figure 14 (B) illustrates an example of a pixel (PIX) including a liquid crystal element. The pixel (PIX) has a transistor (TR), a liquid crystal element (LC), and a capacitance element (CAP).

[0205] A transistor (TR) is a switching element that controls the electrical connection between one electrode of a liquid crystal element (LC) and a source line (L_Y), and its on and off states are controlled by a scan signal input from a gate.

[0206] In addition, it is desirable to apply an oxide semiconductor or polycrystalline silicon to the semiconductor layer where the channel of the transistor (TR) is formed.

[0207] A liquid crystal element (LC) has two electrodes and a liquid crystal. The orientation of the liquid crystal changes due to the action of an electric field between the two electrodes. Among the two electrodes of the liquid crystal element (LC), the electrode connected to the source line (L_Y) through a transistor (TR) corresponds to the pixel electrode, and the electrode connected to the common line (L_com) to which Vcom is applied corresponds to the common electrode.

[0208] A capacitance element (CAP) is connected in parallel with a liquid crystal element (LC). In this case, one electrode of the capacitance element is connected to the source or drain of a transistor (TR), and the other electrode of the capacitance element is connected to a capacitance line (L_cap) to which a capacitance line voltage is applied.

[0209] In addition, although the present invention has been described with examples of cases where a liquid crystal element (LC) or a light-emitting element (EL) is used as a display element, the present invention is not limited thereto.

[0210] For example, in the present specification, a display element, a display device including a display element, a light-emitting element, and a light-emitting device including a light-emitting element may be of various forms or may include various elements. Examples of display elements, display devices, light-emitting elements, or light-emitting devices include EL (electroluminescence) elements (EL elements including organic and inorganic materials, organic EL elements, inorganic EL elements), LEDs (white LEDs, red LEDs, green LEDs, blue LEDs, etc.), transistors (transistors that emit light according to current), electron emission elements, liquid crystal elements, electronic ink, electrophoretic elements, diffraction light valves (GLVs), plasma displays (PDPs), display elements using MEMS (micro electro mechanical systems), digital micro mirror devices (DMDs), digital micro shutters (DMS), MIRASOL (registered trademark), interferometric modulator (IMOD) elements, shutter-type MEMS display elements, optical interference-type MEMS display elements, electrowetting elements, piezoelectric ceramic displays, carbon nanotubes, etc., and display media in which contrast, brightness, reflectance, transmittance, etc. change due to electromagnetic action. Examples of display devices using EL elements include EL displays. Examples of display devices using electron emission elements include field emission displays (FEDs) or surface-conduction electron-emitter (SED) flat displays. Examples of display devices using liquid crystal elements include liquid crystal displays (transmissive liquid crystal displays, transflective liquid crystal displays, reflective liquid crystal displays, direct-view liquid crystal displays, and projection liquid crystal displays). Examples of display devices using electronic ink or electrophoretic elements include electronic paper.In addition, when implementing a transflective liquid crystal display or a reflective liquid crystal display, it is preferable that some or all of the pixel electrodes function as reflective electrodes. For example, it is preferable that some or all of the pixel electrodes include aluminum, silver, etc. In addition, in this case, it is also possible to provide a memory circuit such as SRAM under the reflective electrodes. By doing so, power consumption can be further reduced.

[0211] [Example of touch panel operation method]

[0212] Hereinafter, the operation of a touch panel (80) that displays a video in a first mode and a still image in a second mode using the timing chart shown in FIG. 15 will be described. FIG. 15 shows the signal waveform of a vertical synchronization signal (Vsync) and a data signal (Vdata) output to a source line (L_Y) from a source driver (803).

[0213] FIG. 15 is a timing chart of a touch panel (80) in the case of displaying a video, followed by a still image, and then displaying a video again as an example. Here, the image data is assumed to have movement from the 1st frame to the k-th frame. The image data is assumed to have no movement from the (k+1)th frame to the (k+3)th frame. The image data from the (k+4)th frame onwards is assumed to have movement. Also, k is an integer greater than or equal to 2.

[0214] During the initial video display period, the motion detection unit (811) determines that there is motion in the image data of each frame. Accordingly, the touch panel (80) operates in the first mode. The control circuit (810) outputs the image signal (Video) to the source driver (803) at a frame frequency greater than or equal to the frequency of the vertical synchronization signal, in this case, the frame frequency f1. Then, the source driver (803) continuously outputs the data signal (Vdata) to the source line (L_Y). In addition, the length of one frame period during the video display period is indicated as 1 / f1 (second).

[0215] Subsequently, during the still image display period, the motion detection unit (811) performs image processing for motion detection and determines that there is no motion in the image data of the k+1th frame. Accordingly, the touch panel (80) operates in the second mode. The control circuit (810) outputs the image signal (Video) to the source driver (803) with a frame frequency less than the frequency of the vertical synchronization signal, in this case, the frame frequency f2. The source driver (803) then intermittently outputs the data signal (Vdata) to the source line (L_Y). Additionally, the length of one frame period during the still image display period is indicated as 1 / f2 (second).

[0216] Since the source driver (803) can intermittently output a data signal (Vdata), it is desirable to likewise intermittently supply control signals (start pulse signal, clock signal, etc.) to the gate driver (802) and the source driver (803), thereby allowing the gate driver (802) and the source driver (803) to be stopped periodically.

[0217] The intermittent output of the data signal (Vdata) to the source line (L_Y) in the second mode is described in detail. For example, as shown in FIG. 15, in the (k+1)th frame, the control circuit (810) outputs a control signal to the gate driver (802) and the source driver (803), and outputs an image signal (Video) to the source driver (803) at a frame frequency f2. The source driver (803) outputs the data signal recorded in the previous period, that is, the data signal (k_data) output to the source line (L_Y) in the kth frame, to the source line (L_Y). In this way, during the still image display period, the data signal (k_data) recorded in the previous period is repeatedly recorded on the source line (L_Y) every period 1 / f2 (second). Therefore, the voltage corresponding to the gradation of the image signal of the same image can be refreshed. By regularly refreshing, flicker caused by gradation discrepancies resulting from voltage drop can be reduced, and the touch panel can be made with improved display quality.

[0218] And the control circuit (810) operates in a second mode until a determination result or sensor signal input is obtained from the motion detection unit (811) that there is movement in the image data.

[0219] Then, when the motion detection unit (811) determines that there is motion in the image data after the (k+4)th frame, the touch panel (80) operates again in the first mode. The control circuit (810) outputs the image signal (Video) to the source driver (803) with a frame frequency greater than or equal to the frequency of the vertical synchronization signal, in this case, frame frequency f1. Then, the source driver (803) continuously outputs the data signal (Vdata) to the source line (L_Y).

[0220] As described in Embodiment 1, a touch panel according to one embodiment of the present invention has a configuration in which a display device and a touch sensor are provided between two flexible substrates, and the distance between the display device and the touch sensor can be made very short. In this case, noise during the operation of the display device is likely to spread to the touch sensor, and there is a risk that the sensitivity of the touch sensor may be reduced, but by applying the driving method described as an example in this embodiment, a touch panel that achieves both thinness and high detection sensitivity can be realized.

[0221] This embodiment may be implemented by appropriately combining at least a part thereof with other embodiments described in this specification.

[0222] (Embodiment 4)

[0223] In this embodiment, an example is described of a case in which a protective film, etc., is formed on the surface of a member such as the above-described touch panel using an aerosol deposition method.

[0224] Aerosol deposition (AD) is a method of forming a film without heating the substrate. An aerosol refers to fine particles dispersed in a gas.

[0225] Figure 16 (A) illustrates an example of the cross-sectional structure of a film-forming device for forming a film by the aerosol deposition method.

[0226] The film forming device has at least a chamber (53), a stage (59) that supports a film-forming material (e.g., a substrate (60)) installed in the chamber (53), an exhaust device (55) such as a pump (mechanical booster pump, rotary pump, etc.) that vacuums the inside of the chamber (53), an ejection means (nozzle (56), etc.), a raw material container (63) connected to the ejection means through a supply line, a gas line for introducing a carrier gas, and a gas tank (51).

[0227] First, the moisture inside the raw material container (63) is removed by heating the raw material powder inside the raw material container (63) by applying vibration (ultrasonic waves, etc.) by means of a vibrator (62), and the moisture is exhausted to the exhaust device (54) through the exhaust line.

[0228] Next, a carrier gas is introduced into the raw material container (63) through a gas line to aerosolize the raw material powder. Dry air, oxygen, and an inert gas (nitrogen, helium gas, argon gas, etc.) are used as the carrier gas, and the flow rate of the carrier gas can be controlled by a flow meter (52).

[0229] In a chamber (53) depressurized by an exhaust device (55), an aerosol containing microparticles of an inorganic material (50 nm or more and 500 nm or less) is ejected from a nozzle (56) and solidified by colliding the microparticles with a substrate (60). A film formation method capable of forming an inorganic material layer on the surface of a substrate (60) is called the AD method. The positions of the film-forming object (e.g., substrate (60)) and the nozzle (56) are appropriately determined so that the aerosol ejected from the nozzle (56) collides with the film-forming object (e.g., substrate (60)) at a predetermined angle of incidence θ (θ = 0˚ or more and 90˚ or less). The larger the angle of incidence, the greater the impact force when the microparticles collide with the surface of the substrate (60). On the other hand, the smaller the angle of incidence, the smaller the mechanical action, including the impact force when the microparticles collide with the surface of the substrate (60). When spraying an aerosol onto a film (e.g., a substrate (60)), the optimal angle of incidence θ may vary depending on the material of the microparticle used, so it is important to set this angle of incidence θ appropriately.

[0230] Figure 16 (A) illustrates an example of a device in which the angle of incidence θ is fixed by an angle adjustment means (61), but is not limited thereto. It may be a device in which the nozzle is fixed and the angle of the stage (59) can be appropriately changed.

[0231] Additionally, an enlarged perspective view of the end portion of the nozzle (56) is shown in (B) of FIG. 16. Here, a nozzle having a wide nozzle inlet (57) is shown, but it is not limited to this and a nozzle having multiple nozzle inlets may be used.

[0232] Additionally, a mask having an opening between the nozzle (56) and the substrate (60) may be provided to selectively form a film. Furthermore, the substrate (60) may be moved in the X or Y direction by a driving device (58) that moves the stage (59) in the X or Y direction to form a film over a large area.

[0233] Inorganic materials such as aluminum oxide, yttrium oxide, aluminum nitride, silicon carbide, silicon nitride, and titanium oxide can be used as materials for the fine particles in the AD method.

[0234] Films can be formed on the surface of resin substrates or organic material layers at low temperatures, such as room temperature, by the aerosol deposition (AD) method. In the AD method, fine particles collide with the substrate surface, undergoing plastic deformation or, in some cases, shattering and adhering to the substrate. As this phenomenon is repeated, the film grows.

[0235] In this embodiment, for example, a film formed by an aerosol deposition method can be used as a protective layer (178) applied to the surface of a substrate on the touch sensor side of a touch panel (100). For example, an aluminum oxide film with a film thickness of 100 nm or more and 200 nm or less is formed on an aramid film by an aerosol deposition method to serve as the protective layer (178). Since the film formed by the aerosol deposition method is dense and fine irregularities are formed on the film surface at the same time, it can become a protective film with strong adhesion.

[0236] (Embodiment 5)

[0237] In this embodiment, an electronic device that can be manufactured by applying a touch panel according to one form of the present invention is described using FIGS. 17 and 18.

[0238] Examples of electronic devices include television units (also called television or television receivers), monitors for computers, digital cameras, digital video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices), portable game consoles, portable information terminals, audio players, and large game machines such as pachinko machines.

[0239] In addition, since the device according to one embodiment of the present invention is flexible, it can be installed along the curved surface of the inner or outer wall of a house or building, or the interior or exterior of a car.

[0240] FIG. 17 (A) illustrates an example of a mobile phone. The mobile phone (7400) has, in addition to a display unit (7402) provided in a housing (7401), an operation button (7403), an external connection port (7404), a speaker (7405), a microphone (7406), etc. Furthermore, the mobile phone (7400) is manufactured by using a display device manufactured by applying one embodiment of the present invention in the display unit (7402). By one embodiment of the present invention, a highly reliable mobile phone having a curved display unit can be provided with a high yield.

[0241] The mobile phone (7400) illustrated in (A) of FIG. 17 can input information by touching a finger or the like to the display unit (7402). Additionally, various operations such as making a phone call or entering text can be performed by touching a finger or the like to the display unit (7402).

[0242] In addition, the power ON / OFF operation can be performed by operating the control button (7403) or the type of image displayed on the display unit (7402) can be switched. For example, the email composition screen can be switched to the main menu screen.

[0243] Figure 17 (B) illustrates an example of a wristwatch-type portable information terminal. The portable information terminal (7100) has a housing (7101), a display unit (7102), a band (7103), a buckle (7104), an operation button (7105), and an input / output terminal (7106), etc.

[0244] The portable information terminal (7100) can run various applications such as mobile phone, email, reading and writing text, music playback, internet communication, and computer games.

[0245] The display unit (7102) has a curved display surface and can display along the curved display surface. Additionally, the display unit (7102) has a touch sensor and can be operated by touching a finger or stylus to the screen. For example, an application can be launched by touching an icon (7107) displayed on the display unit (7102).

[0246] In addition to time setting, various functions can be added to the operation button (7105), such as power ON / OFF operation, wireless communication ON / OFF operation, activation and deactivation of silent mode, and activation and deactivation of power saving mode. For example, the functions of the operation button (7105) can be freely set by an operating system installed on the portable information terminal (7100).

[0247] In addition, the portable information terminal (7100) can perform short-range wireless communication according to communication standards. For example, hands-free calling is also possible through mutual communication with a headset capable of wireless communication.

[0248] Additionally, the portable information terminal (7100) has an input / output terminal (7106) and can directly exchange data with another information terminal through a connector. It can also be charged through the input / output terminal (7106). Additionally, the charging operation may be performed by wireless power supply without using the input / output terminal (7106).

[0249] A light-emitting device manufactured by applying one embodiment of the present invention is provided in the display portion (7102) of the portable information terminal (7100). By one embodiment of the present invention, a highly reliable portable information terminal having a curved display portion can be provided with a high yield.

[0250] (C) of FIG. 17 illustrates an example of a portable display device. The display device (7300) has a housing (7301), a display portion (7302), an operating button (7303), a handle (7304) for pulling out the display portion (display portion pull), and a control portion (7305).

[0251] The display device (7300) has a flexible display part (7302) rolled into a scroll shape within a cylindrical housing (7301).

[0252] Additionally, the display device (7300) can receive a video signal via the control unit (7305) and display the received video on the display unit (7302). Additionally, the control unit (7305) has a battery. Furthermore, the control unit (7305) may be configured to receive video signals or power directly from the outside through wiring by providing a terminal unit for connecting a connector.

[0253] In addition, power ON / OFF operation or switching of the displayed image can be performed by means of the operation button (7303).

[0254] Fig. 17 (D) illustrates a display device (7300) with the display unit (7302) pulled out by the handle (7304). In this state, an image can be displayed on the display unit (7302). Additionally, it can be easily operated with one hand by means of an operation button (7303) placed on the surface of the housing (7301). Furthermore, as shown in Fig. 17 (C), it can be easily operated with one hand by placing the operation button (7303) on one side rather than in the center of the housing (7301).

[0255] Additionally, a reinforcing frame may be provided on the side of the display part (7302) to flatten the display surface of the display part (7302) when the display part (7302) is taken out.

[0256] In addition, this configuration may be configured to additionally provide a speaker in the housing to output sound based on an audio signal received along with the video signal.

[0257] A foldable portable information terminal (310) is illustrated in FIG. 18 (A) to (C). FIG. 18 (A) is the portable information terminal (310) in an unfolded state. FIG. 18 (B) is the portable information terminal (310) in a state of transition from one side to the other, either unfolded or folded. FIG. 18 (C) is the portable information terminal (310) in a folded state. When the portable information terminal (310) is folded, it is easy to carry, and when unfolded, the visibility of the display is excellent due to the large, seamless display area.

[0258] The display panel (312) is supported by three housings (315) connected by a hinge (313). The portable information terminal (310) can be reversibly deformed from an unfolded state to a folded state by bending it between two housings (315) using the hinge (313). A display device manufactured by applying one embodiment of the present invention can be used in the display panel (312). For example, a display device that bends with a radius of curvature of 1 mm or more and 150 mm or less can be applied.

[0259] A foldable portable information terminal (320) is illustrated in (D) and (E) of FIG. 18. FIG. 18 (D) illustrates a portable information terminal (320) in a folded state such that the display portion (322) is on the outside. FIG. 18 (E) illustrates a portable information terminal (320) in a folded state such that the display portion (322) is on the inside. When the portable information terminal (320) is not in use, folding it so that the non-display portion (325) is on the outside can prevent the display portion (322) from getting dirty or cracked. A display device manufactured by applying one embodiment of the present invention can be used in the display portion (322).

[0260] Figure 18 (F) is a perspective view for explaining the external appearance of a portable information terminal (330). Figure 18 (G) is a top view of the portable information terminal (330). Figure 18 (H) is a perspective view for explaining the external appearance of a portable information terminal (340).

[0261] The portable information terminal (330, 340) functions as one or more selected from, for example, a telephone, a notebook, or an information viewing device. Specifically, each can be used as a smartphone.

[0262] The portable information terminal (330, 340) may display text or image information on its multiple surfaces. For example, three operation buttons (339) may be displayed on one surface (see (F) and (H) of FIG. 18). Additionally, information (337) (rectangles drawn with dashed lines in the drawings) may be displayed on other surfaces (see (G) and (H) of FIG. 18). Examples of information (337) include notifications such as email, social networking service (SNS), or incoming calls, the subject of email or SNS notifications, the sender's name, date, time, battery level, signal strength, etc. Alternatively, operation buttons (339), icons, etc. may be displayed instead of information (337) at the location where the information (337) is displayed. Also, FIG. 18 (F) and (G) illustrate an example where information (337) is displayed on the top surface, but the present invention is not limited thereto. For example, it may be displayed on the side, such as the portable information terminal (340) shown in (H) of FIG. 18.

[0263] For example, a user of a portable information terminal (330) can check the display (information (337) here) while the portable information terminal (330) is placed in the chest pocket of the clothing.

[0264] Specifically, the caller's phone number or name of the incoming call is displayed in a location visible from above the mobile information terminal (330). The user can decide whether to answer the call by checking the display without taking the mobile information terminal (330) out of their pocket.

[0265] A display device manufactured by applying one embodiment of the present invention can be used in the display portion (333) that the housing (335) of the portable information terminal (330) and the housing (336) of the portable information terminal (340) each have. By one embodiment of the present invention, a highly reliable display device having a curved display portion can be provided with a high yield.

[0266] In addition, information may be displayed on three or more surfaces, such as the portable information terminal (345) shown in (I) of FIG. 18. Here, an example is shown in which information (355), information (356), and information (357) are displayed on different surfaces.

[0267] A display device manufactured by applying one embodiment of the present invention can be used in the display portion (358) of the housing (351) of the portable information terminal (345). By one embodiment of the present invention, a highly reliable display device having a curved display portion can be provided with a high yield.

[0268] A touch panel according to one embodiment of the present invention can be applied to the display portion of the electronic device described above. Accordingly, an electronic device can be made that achieves high detection sensitivity along with thinness, lightness, and multi-functionality.

[0269] This embodiment may be implemented by appropriately combining at least a part thereof with other embodiments described in this specification.

[0270] (Embodiment 6)

[0271] In this embodiment, an oxide semiconductor that can be preferably used in the semiconductor layer of a semiconductor device applicable to a display panel according to one embodiment of the present invention is described.

[0272] Oxide semiconductors have an energy gap of 3.0 eV or more, and if an oxide semiconductor film obtained by sufficiently reducing the carrier density by processing the oxide semiconductor under appropriate conditions is applied to a transistor, the off-current can be made very low compared to a conventional transistor using silicon.

[0273] It is preferable that the applicable oxide semiconductor includes at least indium (In) or zinc (Zn). It is particularly preferable that it includes both indium and zinc. In addition, as a stabilizer for reducing deviations in the electrical characteristics of a transistor using the oxide semiconductor, it is preferable to include one or more types selected from gallium (Ga), tin (Sn), hafnium (Hf), zirconium (Zr), titanium (Ti), scandium (Sc), yttrium (Y), and lanthanides (e.g., cerium (Ce), neodymium (Nd), gadolinium (Gd)), in addition to these.

[0274] As oxide semiconductors, for example, indium oxide, tin oxide, zinc oxide, In-Zn oxide, Sn-Zn oxide, Al-Zn oxide, Zn-Mg oxide, Sn-Mg oxide, In-Mg oxide, In-Ga oxide, In-Ga-Zn oxide (also denoted as IGZO), In-Al-Zn oxide, In-Sn-Zn oxide, Sn-Ga-Zn oxide, Al-Ga-Zn oxide, Sn-Al-Zn oxide, In-Hf-Zn oxide, In-Zr-Zn oxide, In-Ti-Zn oxide, In-Sc-Zn oxide, In-Y-Zn oxide, In-La-Zn oxide, In-Ce-Zn oxide, In-Pr-Zn oxide, In-Nd-Zn oxide, In-Sm-Zn oxide, In-Eu-Zn oxide, In-Gd-Zn oxide, In-Tb-Zn oxide, In-Dy-Zn oxide, In-Ho-Zn oxide, In-Er-Zn oxide, In-Tm-Zn oxide, In-Yb-Zn oxide, In-Lu-Zn ​​oxide, In-Sn-Ga-Zn oxide, In-Hf-Ga-Zn oxide, In-Al-Ga-Zn oxide, In-Sn-Al-Zn oxide, In-Sn-Hf-Zn oxide, and In-Hf-Al-Zn oxide can be used.

[0275] Here, In-Ga-Zn oxide refers to an oxide containing In, Ga, and Zn as main components, regardless of the ratio of In, Ga, and Zn. Additionally, it may contain metal elements other than In, Ga, and Zn.

[0276] In addition, InMO3(ZnO) as an oxide semiconductor m A material denoted as (m>0, and m is not an integer) may also be used. Additionally, M represents one or more metal elements selected from Ga, Fe, Mn, and Co, or an element functioning as the stabilizer described above. Additionally, In2SnO5(ZnO) as an oxide semiconductor n You may use materials denoted as (n>0, and n is an integer).

[0277] For example, it is preferable to use an In-Ga-Zn oxide or an oxide having a composition near that of In:Ga:Zn=1:1:1, In:Ga:Zn=1:3:2, In:Ga:Zn=1:3:4, In:Ga:Zn=1:3:6, In:Ga:Zn=3:1:2, or In:Ga:Zn=2:1:3.

[0278] When an oxide semiconductor film contains a large amount of hydrogen, it combines with the oxide semiconductor, causing some of the hydrogen to become donors and generate electrons, which act as carriers. Consequently, the threshold voltage of the transistor shifts in the negative direction. Therefore, it is desirable to achieve high purity by performing a dehydration treatment after forming the oxide semiconductor film to remove hydrogen or moisture, thereby ensuring that impurities are contained as little as possible.

[0279] In addition, oxygen in the oxide semiconductor film may also be reduced simultaneously due to the dehydration treatment (dehydrogenation treatment) of the oxide semiconductor film. Therefore, it is desirable to perform a treatment to add oxygen to the oxide semiconductor film in order to compensate for the increased oxygen deficit caused by the dehydration treatment (dehydrogenation treatment) of the oxide semiconductor film. In this specification and other documents, the act of supplying oxygen to the oxide semiconductor film may be described as an oxygenation treatment. Alternatively, the act of making the oxygen contained in the oxide semiconductor film greater than the stoichiometric composition may be described as an over-oxygenation treatment.

[0280] In this way, the oxide semiconductor film can become a Type i (intrinsic) or substantially Type i (intrinsic) oxide semiconductor film infinitely close to Type i by removing hydrogen or moisture through dehydration treatment and preserving oxygen vacancies through oxygenation treatment. Furthermore, substantially intrinsic means that the carrier density of the oxide semiconductor layer is 1×10⁻⁶ 17 / cm 3 Less than, preferably 1×10 15 / cm 3 Less than, more preferably, 1×10 13 / cm 3 Less than, more preferably 8×10 11 / cm 3 Less than, more preferably 1×10 11 / cm 3 Less than, more preferably 1×10 10 / cm 3 Less than and 1×10 -9 / cm 3 It speaks of something more than that.

[0281] Furthermore, transistors using such type i or substantially type i oxide semiconductor films can have excellent off-current characteristics. For example, the drain current in the off state of a transistor using an oxide semiconductor film is 1×10⁻⁶ at room temperature (approximately 25°C). -18 A or less, preferably 1×10 -21A or less, more preferably 1×10 -24 A or less, or 1×10⁻⁶ at 85℃ -15 A or less, preferably 1×10 -18 A or less, more preferably 1×10 -21 It can be less than or equal to A. In addition, the transistor being in the off state refers to a state in which, for an n-channel transistor, the gate voltage is sufficiently smaller than the threshold voltage. Specifically, if the gate voltage is 1V or more, 2V or more, or 3V or more less than the threshold voltage, the transistor is in the off state.

[0282] The structure of the oxide semiconductor film is described below.

[0283] In addition, in this specification, "parallel" refers to a state in which two straight lines are arranged at an angle of -10° or greater and 10° or less. Accordingly, cases ranging from -5° to 5° or less are also included in this category. In addition, "substantially parallel" refers to a state in which two straight lines are arranged at an angle of -30° or greater and 30° or less. In addition, "perpendicular" refers to a state in which two straight lines are arranged at an angle of 80° or greater and 100° or less. Accordingly, cases ranging from 85° to 95° or less are also included in this category. In addition, "substantially perpendicular" refers to a state in which two straight lines are arranged at an angle of 60° or greater and 120° or less.

[0284] Additionally, in this specification, trigonal and rhombohedral crystal systems are included in the hexagonal crystal system.

[0285] Oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Non-single-crystal oxide semiconductors include CAAC-OS (C-Axis Aligned Crystalline Oxide Semiconductor), polycrystalline oxide semiconductors, microcrystalline oxide semiconductors, and amorphous oxide semiconductors.

[0286] Furthermore, from another perspective, oxide semiconductors are divided into amorphous oxide semiconductors and other crystalline oxide semiconductors. Crystalline oxide semiconductors include single-crystal oxide semiconductors, CAAC-OS, polycrystalline oxide semiconductors, and microcrystalline oxide semiconductors.

[0287] First, let's explain CAAC-OS. CAAC-OS can also be referred to as an oxide semiconductor containing CANC (C-Axis Aligned nanocrystals).

[0288] CAAC-OS is an oxide semiconductor comprising multiple c-axis oriented crystal portions (also called pellets).

[0289] When observing the combined image of the bright-field image and diffraction pattern of CAAC-OS (also called a high-resolution TEM image) using a transmission electron microscope (TEM), multiple pellets are identified. However, even when observing the high-resolution TEM image, the boundaries of the pellets, i.e., the grain boundaries, are not clearly identified. Therefore, it can be said that the degradation of electron mobility caused by grain boundaries is unlikely to occur in CAAC-OS.

[0290] The following describes a CAAC-OS observed by TEM. Figure 19 (A) is a high-resolution TEM image of a cross-section of the CAAC-OS observed from a direction substantially parallel to the sample surface. A spherical aberration corrector function was used for observing the high-resolution TEM image. In particular, a high-resolution TEM image using the spherical aberration corrector function is referred to as a Cs-corrected high-resolution TEM image. A Cs-corrected high-resolution TEM image can be obtained, for example, by an atomic resolution analysis electron microscope (JEM-ARM200F, manufactured by JEOL Ltd.).

[0291] Figure 19 (B) is a Cs-corrected high-resolution TEM image of region (1) in Figure 19 (A). Looking at Figure 19 (B), it is confirmed that metal atoms are arranged in layers in the pellet. Each layer of metal atoms has an arrangement that reflects the irregularities of the surface on which the CAAC-OS film is formed (also called the surface to be formed) or the upper surface of the CAAC-OS, and is parallel to the surface to be formed or the upper surface of the CAAC-OS.

[0292] As shown in Fig. 19 (B), CAAC-OS has a characteristic atomic arrangement. In Fig. 19 (C), the characteristic atomic arrangement is indicated by auxiliary lines. From Fig. 19 (B) and (C), it can be seen that the size of a single pellet is approximately 1 nm or more and 3 nm or less, and the size of the gap created by the slope between the pellets is approximately 0.8 nm. Therefore, the pellets can be referred to as nanocrystals (nc).

[0293] Here, when the arrangement of the CAAC-OS pellets (5100) on the substrate (5120) is schematically illustrated according to the Cs-corrected high-resolution TEM image, it becomes a structure like stacked bricks or blocks (see (D) of FIG. 19). The slope between the pellets observed in (C) of FIG. 19 corresponds to region (5161) in (D) of FIG. 19.

[0294] Additionally, FIG. 20 (A) is a Cs-corrected high-resolution TEM image of the plane of the CAAC-OS observed from a direction substantially perpendicular to the sample surface. FIG. 20 (B), FIG. 20 (C), and FIG. 20 (D) are Cs-corrected high-resolution TEM images, respectively, of enlarged regions (1), (2), and (3) of FIG. 20 (A). From FIG. 20 (B) to (D), it is confirmed that the pellets have metal atoms arranged in triangles, squares, or hexagons. However, no regularity is observed in the arrangement of metal atoms among the different pellets.

[0295] Next, the CAAC-OS analyzed by X-ray diffraction (XRD) will be described. For example, when the structure of a CAAC-OS containing an InGaZnO4 crystal is analyzed by the out-of-plane method, a peak may appear when the diffraction angle (2θ) is around 31°, as shown in (A) of FIG. 21. Since this peak is attributed to the (009) plane of the InGaZnO4 crystal, it can be confirmed that the CAAC-OS crystal has c-axis orientation and is oriented in a direction in which the c-axis is substantially perpendicular to the surface or upper surface of the CAAC-OS.

[0296] In addition, when structural analysis of CAAC-OS is performed using the out-of-plane method, there are cases where a peak appears near 2θ = 36° in addition to the peak that appears near 2θ = 31°. The peak appearing near 2θ = 36° indicates that some parts of the CAAC-OS contain crystals that do not possess c-axis orientation. A more desirable CAAC-OS is one in which, when structural analysis is performed using the out-of-plane method, a peak appears near 2θ = 31° and no peak appears near 2θ = 36°.

[0297] Meanwhile, when structural analysis of CAAC-OS is performed using the in-plane method, in which X-rays are incident from a direction substantially perpendicular to the c-axis, a peak appears when 2θ is near 56°. This peak is attributed to the (110) plane of the InGaZnO4 crystal. In the case of CAAC-OS, even when 2θ is fixed near 56° and analysis (φ scan) is performed while rotating the sample with the normal vector of the sample plane as the axis (φ-axis), no clear peak appears as shown in (B) of Fig. 21. On the other hand, in the case of the single-crystal oxide semiconductor of InGaZnO4, when 2θ is fixed near 56° and a φ scan is performed, six peaks are observed that are attributed to a crystal plane equivalent to the (110) plane, as shown in (C) of Fig. 21. Therefore, from structural analysis using XRD, it is confirmed that the orientation of CAAC-OS along the a-axis and b-axis is irregular.

[0298] Next, the CAAC-OS analyzed by electron diffraction will be described. For example, regarding a CAAC-OS containing an InGaZnO4 crystal, if an electron beam with a probe diameter of 300 nm is incident parallel to the sample surface, a diffraction pattern such as (A) in FIG. 22 (referred to as a limited-field transmission electron diffraction pattern) may appear. This diffraction pattern includes spots attributed to the (009) plane of the InGaZnO4 crystal. Therefore, through electron diffraction, it can be seen that the pellet contained in the CAAC-OS has c-axis orientation and is oriented in a direction in which the c-axis is substantially perpendicular to the surface to be formed or the upper surface of the CAAC-OS. Meanwhile, FIG. 22 (B) is the diffraction pattern when an electron beam with a probe diameter of 300 nm is incident perpendicularly to the sample surface for the same sample. As can be seen from FIG. 22 (B), a ring-shaped diffraction pattern is confirmed. Therefore, it can be seen by electron diffraction that the a-axis and b-axis of the pellet included in CAAC-OS do not have orientation. In addition, the first ring in (B) of FIG. 22 is thought to be due to the (010) plane and (100) plane, etc. of the crystal of InGaZnO4. In addition, the second ring in (B) of FIG. 22 is thought to be due to the (110) plane, etc.

[0299] Furthermore, CAAC-OS is an oxide semiconductor with a low defect level density. Defects in oxide semiconductors include, for example, defects caused by impurities or oxygen vacancies. Therefore, CAAC-OS can be described as an oxide semiconductor with a low impurity concentration. Additionally, CAAC-OS can be described as an oxide semiconductor with low oxygen vacancies.

[0300] Impurities contained in oxide semiconductors may become carrier traps or carrier sources. Additionally, oxygen vacancies within oxide semiconductors may become carrier traps or carrier sources by capturing hydrogen.

[0301] Impurities are elements other than the main components of oxide semiconductors, including hydrogen, carbon, silicon, and transition metal elements. Elements with a stronger bonding affinity for oxygen than the metal elements constituting the oxide semiconductor (e.g., silicon) disrupt the atomic arrangement of the oxide semiconductor by depriving it of oxygen, thereby becoming a factor that degrades crystallinity. Additionally, heavy metals such as iron and nickel, as well as argon and carbon dioxide, have large atomic radii (or molecular radii), which disrupts the atomic arrangement of the oxide semiconductor and thus reduces crystallinity.

[0302] Furthermore, oxide semiconductors with low defect level density (low oxygen vacancies) can achieve low carrier density. Such oxide semiconductors are referred to as high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors. CAAC-OS has low impurity concentration and low defect level density. In other words, it is prone to becoming a high-purity intrinsic or substantially high-purity intrinsic oxide semiconductor. Consequently, the electrical characteristics of transistors using CAAC-OS rarely exhibit a negative threshold voltage (also known as a normaly-on). Additionally, carrier traps are minimal in high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors. Charges trapped in the carrier traps of oxide semiconductors take a long time to be released, sometimes behaving as if they were fixed charges. Therefore, transistors using oxide semiconductors with high impurity concentration and high defect level density may exhibit unstable electrical characteristics. On the other hand, transistors using CAAC-OS exhibit small fluctuations in electrical characteristics and become highly reliable transistors.

[0303] Furthermore, because CAAC-OS has a low defect level density, carriers generated by light irradiation are rarely trapped in defect levels. Consequently, transistors using CAAC-OS exhibit small variations in electrical characteristics caused by irradiation with visible or ultraviolet light.

[0304] Next, microcrystalline oxide semiconductors will be explained.

[0305] Microcrystalline oxide semiconductors have regions where crystal regions are identified in high-resolution TEM images and regions where crystal regions are not clearly identified. The size of the crystal regions included in microcrystalline oxide semiconductors is often between 1 nm and 100 nm, or between 1 nm and 10 nm. In particular, oxide semiconductors containing nanocrystals that are microcrystalline, ranging from 1 nm to 10 nm or between 1 nm and 3 nm, are referred to as nc-OS (nanocrystalline oxide semiconductor). In nc-OS, for example, crystal grain boundaries may not be clearly identified in high-resolution TEM images. Additionally, nanocrystals may have the same origin as the pellets included in nc-OS. Therefore, the crystal regions of nc-OS may be referred to as pellets below.

[0306] nc-OS exhibits periodicity in atomic arrangement in minute regions (e.g., regions from 1 nm to 10 nm, particularly from 1 nm to 3 nm). Furthermore, nc-OS does not show regularity in crystal orientation between different pellets. Consequently, orientation is not confirmed throughout the entire film. Therefore, depending on the analysis method, it may be impossible to distinguish between nc-OS and amorphous oxide semiconductors. For example, when structural analysis of nc-OS is performed using the out-of-plane method with an XRD device utilizing X-rays with a diameter larger than that of the pellet, peaks representing crystal planes are not detected. Additionally, diffraction patterns such as halo patterns are observed in the electron diffraction pattern (also called limited-field electron diffraction pattern) of nc-OS when observed using an electron beam with a probe diameter larger than that of the pellet (e.g., 50 nm or more). On the other hand, spots are observed in the nanobeam electron diffraction pattern of nc-OS when observed using an electron beam with a probe diameter close to or smaller than that of the pellet. In addition, in the nanobeam electron diffraction pattern of nc-OS, a ring-shaped region with high brightness is observed. Also, multiple spots are observed in the ring-shaped region.

[0307] As such, since no regularity in crystal orientation is observed among the pellets (nanocrystals), nc-OS may also be referred to as an oxide semiconductor containing RANC (Random Aligned nanocrystals) or an oxide semiconductor containing NANC (Non-Aligned nanocrystals).

[0308] nc-OS is an oxide semiconductor with higher regularity than amorphous oxide semiconductors. Therefore, nc-OS has a lower defect level density than amorphous oxide semiconductors. However, nc-OS does not exhibit regularity in crystal orientation between different pellets. Consequently, nc-OS has a higher defect level density compared to CAAC-OS.

[0309] Next, amorphous oxide semiconductors will be explained.

[0310] Amorphous oxide semiconductors are oxide semiconductors in which the atomic arrangement within the film is irregular and does not contain crystalline regions. An example is an oxide semiconductor having an amorphous state, such as quartz.

[0311] In amorphous oxide semiconductors, crystalline regions are not identified in high-resolution TEM images.

[0312] When structural analysis of an amorphous oxide semiconductor is performed using the out-of-plane method with an XRD device, peaks representing crystal planes are not detected. Additionally, a halo pattern is observed in the electron diffraction pattern of the amorphous oxide semiconductor. Furthermore, in the nanobeam electron diffraction pattern of the amorphous oxide semiconductor, no spots are observed, and only a halo pattern is observed.

[0313] There are various views regarding amorphous structures. For example, a structure in which there is no order in the arrangement of atoms is sometimes referred to as a completely amorphous structure. Additionally, a structure that possesses order up to the nearest atomic distance or the second nearest atomic distance but lacks long-range order is sometimes referred to as an amorphous structure. Therefore, according to the strictest definition, an oxide semiconductor that possesses even slight order in the arrangement of atoms cannot be called an amorphous oxide semiconductor. Furthermore, an oxide semiconductor that possesses at least long-range order cannot be called an amorphous oxide semiconductor. Consequently, for example, CAAC-OS and nc-OS cannot be called amorphous oxide semiconductors or completely amorphous oxide semiconductors because they contain crystalline regions.

[0314] In addition, oxide semiconductors may have a structure intermediate between nc-OS and amorphous oxide semiconductors. Oxide semiconductors having such a structure are specifically called a-like OS (amorphous-like Oxide Semiconductor).

[0315] In high-resolution TEM images of a-like OS, voids (also called cavities) may be observed. Additionally, when observing high-resolution TEM images, there are regions where the crystallization is clearly visible and regions where the crystallization is not visible.

[0316] a-like OS is an unstable structure because it has cavities. Below, to demonstrate that a-like OS is an unstable structure compared to CAAC-OS and nc-OS, changes in structure caused by electron irradiation are explained.

[0317] a-like OS (designated as Sample A), nc-OS (designated as Sample B), and CAAC-OS (designated as Sample C) are prepared as samples for electron irradiation. In-Ga-Zn oxide is used for all of these samples.

[0318] First, high-resolution cross-sectional TEM images of each sample are acquired. Looking at the high-resolution cross-sectional TEM images, it can be seen that all of these samples have crystalline regions.

[0319] In addition, the determination of which part is considered as a single crystal region can be performed as follows. For example, it is known that the unit cell of the InGaZnO4 crystal has a structure in which a total of 9 layers, consisting of 3 In-O layers and 6 Ga-Zn-O layers, are layered and superimposed in the c-axis direction. The spacing between these adjacent layers is approximately equal to the lattice plane spacing (also called the d value) of the (009) plane, and this value is calculated to be 0.29 nm from the analysis of the crystal structure. Therefore, a region in which the spacing of the lattice fringe is 0.28 nm or greater and 0.30 nm or less can be considered as a crystal region of InGaZnO4. The lattice fringe corresponds to the ab plane of the InGaZnO4 crystal.

[0320] FIG. 23 shows the average size of the crystallized regions (22 to 45 locations) of each sample. However, the length of the lattice stripes described above is considered as the size of the crystallized regions. From FIG. 23, it can be seen that the crystallized regions of the a-like OS grow larger with increasing cumulative electron irradiation dose. Specifically, as indicated by (1) in FIG. 23, the crystallized region (also called the initial nucleus), which had a size of about 1.2 nm at the beginning of observation by TEM, when the cumulative electron irradiation dose was 4.2 × 10⁻⁶ 8 e - / nm 2 It can be seen that it grows to a size of approximately 2.6 nm. Meanwhile, for nc-OS and CAAC-OS, the cumulative electron irradiation dose from the start of electron irradiation is 4.2 × 10⁻⁶ 8 e - / nm 2 It can be seen that the size of the crystal portion does not change within the range up to [value]. Specifically, as indicated by (2) and (3) in FIG. 23, it can be seen that the size of the crystal portion of nc-OS and CAAC-OS is approximately 1.4 nm and 2.1 nm, respectively, regardless of the cumulative electron irradiation amount.

[0321] As such, in a-like OS, growth of crystal regions due to electron irradiation is sometimes observed. On the other hand, it can be seen that growth of crystal regions due to electron irradiation is hardly observed in nc-OS and CAAC-OS. In other words, it can be seen that a-like OS has an unstable structure compared to nc-OS and CAAC-OS.

[0322] Furthermore, since a-like OS contains cavities, it has a structure with lower density compared to nc-OS and CAAC-OS. Specifically, the density of a-like OS is 78.6% or more and less than 92.3% of the density of a single-crystal oxide semiconductor with the same composition. Additionally, the densities of nc-OS and CAAC-OS are 92.3% or more and less than 100% of the density of a single-crystal oxide semiconductor with the same composition. For oxide semiconductors with a density of less than 78% of the single-crystal oxide semiconductor density, film deposition itself is difficult.

[0323] For example, in an oxide semiconductor satisfying In:Ga:Zn = 1:1:1 [atomic ratio], the density of a single-crystal InGaZnO4 having a rhombohedral structure is 6.357 g / cm³ 3 .... Therefore, for example, in an oxide semiconductor satisfying In:Ga:Zn = 1:1:1 [atomic ratio], the density of the a-like OS is 5.0 g / cm³ 3 Above 5.9 g / cm² 3 It is less than. In addition, for example, in an oxide semiconductor satisfying In:Ga:Zn = 1:1:1 [atomic ratio], the density of nc-OS and the density of CAAC-OS are 5.9 g / cm³ 3 Above 6.3g / cm² 3 It is less than.

[0324] Furthermore, there are cases where single-crystal oxide semiconductors with the same composition do not exist. In such cases, a density equivalent to that of a single-crystal oxide semiconductor with a desired composition can be estimated by combining single-crystal oxide semiconductors with different compositions in arbitrary proportions. The density equivalent to that of a single-crystal oxide semiconductor with a desired composition can be estimated by using a weighted average of the ratios in which single-crystal oxide semiconductors with different compositions are combined. However, when estimating the density, it is desirable to combine as few types of single-crystal oxide semiconductors as possible.

[0325] As such, oxide semiconductors have various structures, and each has various characteristics. In addition, the oxide semiconductor may be a stacked film having two or more types among, for example, amorphous oxide semiconductor, a-like OS, microcrystalline oxide semiconductor, and CAAC-OS.

[0326] The CAAC-OS membrane can be formed, for example, in the following way.

[0327] The CAAC-OS film is formed by the sputtering method using, for example, a target for polycrystalline oxide semiconductor sputtering.

[0328] By increasing the substrate temperature during film deposition, migration of sputtering particles occurs after they reach the substrate. Specifically, the film is deposited by setting the substrate temperature to 100°C or higher and 740°C or lower, preferably 200°C or higher and 500°C or lower. By increasing the substrate temperature during film deposition, migration occurs on the substrate when the sputtering particles reach the substrate, and the flat surface of the sputtering particles adheres to the substrate. At this time, since the sputtering particles are positively charged and repel each other while adhering to the substrate, the sputtering particles do not overlap unevenly, and a CAAC-OS film with a uniform thickness can be deposited.

[0329] By reducing the incorporation of impurities during film formation, the collapse of the crystal state caused by impurities can be suppressed. For example, it is desirable to reduce the concentration of impurities (hydrogen, water, carbon dioxide, nitrogen, etc.) present in the film formation chamber. Additionally, it is desirable to reduce the concentration of impurities in the film formation gas. Specifically, a film formation gas having a dew point of -80°C or lower, preferably -100°C or lower, is used.

[0330] In addition, it is desirable to reduce plasma damage during film deposition by increasing the oxygen ratio in the film deposition gas and optimizing the power. The oxygen ratio in the film deposition gas is 30 vol% or more, preferably 100 vol%.

[0331] Alternatively, a CAAC-OS membrane is formed in the following manner.

[0332] First, a first oxide semiconductor film is formed with a thickness of 1 nm or more and less than 10 nm. The first oxide semiconductor film is formed by a sputtering method. Specifically, the substrate temperature is set to 100°C or higher and 500°C or lower, preferably 150°C or higher and 450°C or lower, and the oxygen ratio in the forming gas is set to 30 vol% or higher, preferably 100 vol%, and the film is formed.

[0333] Next, a heat treatment is performed to convert the first oxide semiconductor film into a first CAAC-OS film with high crystallinity. The temperature of the heat treatment is set to 350°C or higher and 740°C or lower, preferably 450°C or higher and 650°C or lower. In addition, the time of the heat treatment is set to 1 minute or higher and 24 hours or lower, preferably 6 minutes or higher and 4 hours or lower. Furthermore, the heat treatment may be performed in an inert atmosphere or an oxidizing atmosphere. Preferably, the heat treatment is performed in an inert atmosphere first, followed by the heat treatment in an oxidizing atmosphere. By performing the heat treatment in an inert atmosphere, the impurity concentration of the first oxide semiconductor film can be reduced in a short period of time. On the other hand, oxygen vacancies may be generated in the first oxide semiconductor film when the heat treatment is performed in an inert atmosphere. In this case, the oxygen vacancies can be reduced by performing the heat treatment in an oxidizing atmosphere. Additionally, the heat treatment may be performed under reduced pressure of 1000 Pa or lower, 100 Pa or lower, 10 Pa or lower, or 1 Pa or lower. Under reduced pressure, the impurity concentration of the first oxide semiconductor film can be reduced in a shorter time.

[0334] If the thickness of the first oxide semiconductor film is 1 nm or more and less than 10 nm, crystallization by heat treatment becomes easier compared to the case where the thickness is 10 nm or more.

[0335] Next, a second oxide semiconductor film having the same composition as the first oxide semiconductor film is deposited with a thickness of 10 nm or more and 50 nm or less. The second oxide semiconductor film is deposited by a sputtering method. Specifically, the substrate temperature is set to 100°C or more and 500°C or less, preferably 150°C or more and 450°C or less, and the oxygen ratio in the deposition gas is set to 30 vol% or more, preferably 100 vol%, and the film is deposited.

[0336] Next, a heat treatment is performed to grow a second oxide semiconductor film in a solid state from the first CAAC-OS film, thereby forming a second CAAC-OS film with high crystallinity. The temperature of the heat treatment is set to 350°C or higher and 740°C or lower, preferably 450°C or higher and 650°C or lower. In addition, the time of the heat treatment is set to 1 minute or higher and 24 hours or lower, preferably 6 minutes or higher and 4 hours or lower. Furthermore, the heat treatment may be performed in an inert atmosphere or an oxidizing atmosphere. Preferably, the heat treatment is performed in an inert atmosphere first, followed by the heat treatment in an oxidizing atmosphere. By performing the heat treatment in an inert atmosphere, the impurity concentration of the second oxide semiconductor film can be reduced in a short period of time. On the other hand, oxygen vacancies may be generated in the second oxide semiconductor film when the heat treatment is performed in an inert atmosphere. In this case, the oxygen vacancies can be reduced by performing the heat treatment in an oxidizing atmosphere. In addition, the heat treatment may be performed under reduced pressure of 1000 Pa or less, 100 Pa or less, 10 Pa or less, or 1 Pa or less. Under reduced pressure, the impurity concentration of the second oxide semiconductor film can be reduced in a shorter time.

[0337] As described above, a CAAC-OS film with a total thickness of 10 nm or more can be formed.

[0338] This embodiment may be implemented by appropriately combining at least a part thereof with other embodiments described in this specification. Explanation of the symbols

[0339] 51: Gas tank 52: Flow meter 53: Chamber 54: Exhaust system 55: Exhaust system 56: Nozzle 57: Nozzle inlet 58: Driving device 59: Stage 60: Substrate 61: Angle adjustment means 62: Vibrator 63: Raw material container 80: Touch panel 100: Touch panel 101: Board 102: Substrate 110: Display device 111: Display unit 112: Driving circuit 114: IC 120: Touch sensor 121: Electrode 122: Electrode 123: Dielectric layer 125: Insulating layer 131: Wiring 132: Wiring 140: FPC 141: FPC 142: FPC 143: FPC 144: Wiring 151: Adhesive layer 152: Adhesive layer 153: Adhesive layer 155: Connection terminal 156: Connection terminal 157: Connection layer 158: Connection layer 161: Transistor 162: Transistor 163: Transistor 164: Transistor 165: Conductive particles 166: Challenge Floor 171: Insulating layer 172: Insulating layer 173: Insulating layer 175: Insulating layer 176: Insulating layer 178: Protection Layer 180: Light-emitting element 181: Electrode 182: EL layer 183: Electrode 184: Color Filter 185: Black Matrix 191: Adhesive layer 192: Adhesive layer 310: Portable Information Terminal 312: Display panel 313: Hinge 315: Housing 320: Portable Information Terminal 322: Display unit 325: Non-display section 330: Portable Information Terminal 333: Display unit 335: Housing 336: Housing 337: Information 339: Operation button 340: Portable Information Terminal 345: Portable Information Terminal 351: Housing 355: Information 356: Information 357: Information 358: Display unit 501: Pulse voltage output circuit 502: Current detection circuit 503: Capacity 511: Transistor 512: Transistor 513: Transistor 800: Display device 801: Display unit 802: Gate Driver 803: Source driver 804: DA conversion circuit 810: Control circuit 811: Detector 820: Counter circuit 850: Touch sensor 5100: Pellet 5120: Board 5161: Area 7100: Portable Information Terminal 7101: Housing 7102: Display unit 7103: Band 7104: Buckle 7105: Operation button 7106: Input / Output Terminal 7107: Icon 7300: Display device 7301: Housing 7302: Display unit 7303: Operation button 7304: Handle 7305: Control unit 7400: Mobile phone 7401: Housing 7402: Display unit 7403: Operation button 7404: External access port 7405: Speaker 7406: Microphone

Claims

Claim 1 delete Claim 2 A display device comprising: a substrate; a first insulating layer; a transistor; a second insulating layer; a resin layer; and a conductive material, wherein the first insulating layer comprises an upper region of the substrate, the transistor comprises an upper region of the first insulating layer, the second insulating layer comprises an upper region of the first insulating layer, the resin layer comprises an upper region of the first insulating layer, the resin layer comprises an upper region of the second insulating layer, the resin layer comprises an upper region of the conductive material, the conductive material comprises a region between the transistor and the end of the substrate when viewed in a planar view, the resin layer comprises a region that overlaps with a channel forming region of the transistor, and the resin layer comprises a region between the second insulating layer and the conductive material. Claim 3 A display device comprising: a substrate; a first insulating layer; a transistor; a second insulating layer; a resin layer; and a conductive material, wherein the first insulating layer comprises an upper region of the substrate, the transistor comprises an upper region of the first insulating layer, the second insulating layer comprises an upper region of the first insulating layer, the resin layer comprises an upper region of the first insulating layer, the resin layer comprises an upper region of the second insulating layer, the resin layer comprises an upper region of the conductive material, the conductive material comprises a region between the transistor and the end of the substrate when viewed in a planar view, the resin layer comprises a region that overlaps with the channel forming region of the transistor, the resin layer comprises a region between the second insulating layer and the conductive material, and the end of the resin layer comprises a region that overlaps with the upper region of the second insulating layer. Claim 4 A display device according to claim 2 or 3, further comprising an adhesive layer, wherein the substrate is flexible, and the adhesive layer comprises a region between the substrate and the first insulating layer. Claim 5 A display device according to claim 2 or 3, wherein the resin layer includes an area overlapping with a touch sensor.

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