WO2020039675A1

WO2020039675A1 - Display device

Info

Publication number: WO2020039675A1
Application number: PCT/JP2019/020194
Authority: WO
Inventors: 岳大野; 泰折田; 成一郎森; 中村　達也
Original assignee: 三菱電機株式会社
Priority date: 2018-08-22
Filing date: 2019-05-22
Publication date: 2020-02-27

Abstract

A cover panel (13) comprises a first surface (F1) to be subject to pointing by a pointing body (900), and a second surface (F2) which is opposite to the first surface (F1). A position detection layer (LD) above the second surface (F2) has a distance t from the first surface (F1). The position detection layer (LD) comprises first electrodes (21) and second electrodes (31). A display panel (2) comprises a pressure detection electrode (40) which faces the position detection layer (LD) with a gap (GP) therebetween. Given that a length s is defined as the maximum length of line segments which, in plan view, pass through arbitrary points in gaps between the first electrodes (21) and the second electrodes (31) and which join the first electrodes (21) and the second electrodes (31) at the shortest distances, an inequality t>s/2 is satisfied.

Description

Display device

The present invention relates to a display device, and more particularly to a display device capable of specifying a position pointed by a pointer.

Recently, display devices with a touch panel have been used. The touch panel is a device that specifies a position touched by an indicator such as a finger. A touch panel has attracted attention as one of excellent user interface (UI) means. Various types of touch panels such as a resistive type and a capacitive type have been commercialized.

As one of the capacitive touch panels, there is a projected capacitive touch panel (see, for example, JP-A-2012-103761 (Patent Document 1)). According to the projection capacitive method, touch detection is possible even when the front side of the sensor built in the touch panel is covered with a protective plate such as a glass plate having a thickness of about several mm. This method has the following advantages: the protection plate can be placed on the front surface, which makes it more robust, the touch detection is possible even when gloves are worn, and the life is longer because there are no moving parts. Have. According to WO 2000-044018 (Patent Document 2), a key matrix including an array of a plurality of driving / receiving electrode pairs is provided. The electric field between the electrodes changes depending on an object that contacts the substrate, such as a finger. A change in the coupling capacitance (mutual electrode capacitance) accompanying this is detected as a charge amount.

Recently, it has recently been proposed to add a pressure detection function to a projected capacitive touch panel. For example, International Patent Application Publication No. 2014-080924 (Patent Document 3) discloses a proximity / contact sensor. The first detecting means of the proximity / contact sensor has a sheet-like upper electrode layer and a sheet-like lower electrode layer. The upper electrode layer has a plurality of upper electrodes that conduct electricity in one direction. The lower electrode layer has a plurality of lower electrodes that are insulated from the upper electrode and are energized in another direction different from the current flow direction of the upper electrode, and are disposed to cross the upper electrode. An intermediate layer that is deformed in accordance with the contact or pressure of the object is provided below the first detection unit. Below the intermediate layer, a second detection means for detecting an electrical change according to the contact or pressing force of the object is provided. When the target approaches the first detection means, the approach of the target is determined based on an electrical change between the upper electrode and the lower electrode. At the same time, when the object touches or presses the first detecting means, based on the electrical change detected by the second detecting means, the position of the contact or pressing of the object and the pressure Values are specified. Switching is performed at predetermined intervals so that either one of the first detection means and the second detection means is connected to the ground.

JP 2012-103761 A International Publication No. 2000-0404018 International Publication No. 2014-080924

中 During use of the touch panel, conductive foreign matter such as water droplets may adhere to the touch surface. The adhesion of foreign matter can disturb the operation of pressure detection. In the technology described in WO-A-2014-92424, such a disturbance in the detection operation may be increased.

SUMMARY An advantage of some aspects of the invention is to provide a display device that can prevent pressure detection from being disturbed by a foreign substance on a touch surface. .

表示 The display device of the present invention can specify the position indicated by the indicator. The display device has a cover panel, a position detection layer, a display panel, a first charge detector, and an excitation signal source. The cover panel has a first surface to be indicated by the indicator and a second surface opposite to the first surface. The position detection layer is provided directly or indirectly on the second surface of the cover panel, and has a distance t from the first surface. The position detection layer includes a plurality of first electrodes, a plurality of second electrodes, and an interlayer insulating film. The plurality of first electrodes run in parallel with each other. The plurality of second electrodes run in parallel with each other and intersect with the plurality of first electrodes. The interlayer insulating film insulates between the plurality of first electrodes and the plurality of second electrodes in the thickness direction. The display panel has a pressure detection electrode facing the position detection layer via the gap in the thickness direction, and supports the cover panel so that the second surface of the cover panel can bend toward the gap. I have. The maximum length of a line connecting the first electrode and the second electrode at the shortest distance through an arbitrary point in the interval between the plurality of first electrodes and the plurality of second electrodes in plan view is represented by length s. When t is defined, t> s / 2 is satisfied.

According to the present invention, the inequality t> s / 2 is satisfied. Thereby, the space between the pressure detection electrode and the first surface of the cover panel, which is the touch surface indicated by the indicator, is sufficiently shielded by the first electrode and the second electrode of the position detection layer. Therefore, disturbance of the pressure detection by the foreign matter on the touch surface is prevented.

The objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

FIG. 2 is a partial cross-sectional view schematically illustrating a configuration of a display device according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view schematically illustrating a layer configuration on the front side of the display device of FIG. 1. FIG. 2 is a plan view schematically showing a configuration of a touch panel according to Embodiment 1 of the present invention. FIG. 2 is a partial plan view schematically showing a configuration of the touch panel according to Embodiment 1 of the present invention. FIG. 5 is a schematic partial sectional view taken along line VV in FIG. 4. FIG. 2 is a diagram schematically illustrating a state in which a pointer comes into contact with the display device of FIG. 1. FIG. 2 is a block diagram schematically showing a configuration of a display device according to Embodiment 1 of the present invention. FIG. 4 is a flowchart schematically showing a detection operation of the display device according to the first embodiment of the present invention. FIG. 7 is a graph showing a relationship between a length s shown in FIG. 4 and a calculated value of a capacitance ratio of the capacitance shown in FIG. 6. FIG. 7 is a schematic diagram showing a state in which a line of electric force from a pressure detection electrode approaches a pointer above a distance of a length s between a column electrode and a row electrode. FIG. 4 is a graph illustrating an example of a detection result of charges induced on a first electrode in a pressure detection operation when a pseudo finger as a pointer is pressed against a clean touch surface of the display device of FIG. 1. FIG. 3 is a graph illustrating an example of a detection result of charges induced on a second electrode in a pressure detection operation when a pseudo finger as a pointer is pressed against a clean touch surface of the display device of FIG. 1. FIG. 7 is a graph illustrating an example of a result of a mutual capacitance detection operation when a pseudo finger as a pointer is pressed against a clean touch surface of the display device of FIG. 1. FIG. 3 is a graph illustrating an example of a detection result of charges induced on a first electrode in a pressure detection operation when salt water adheres to a touch surface of the display device of FIG. 1. FIG. 7 is a graph illustrating an example of a detection result of charges induced on a second electrode in a pressure detection operation when salt water adheres to the touch surface of the display device of FIG. 1. FIG. 2 is a graph illustrating an example of a result of a mutual capacitance detection operation when salt water adheres to a touch surface of the display device of FIG. 1. FIG. 9 is a partial cross-sectional view schematically illustrating a configuration of a display device according to a second embodiment of the present invention. FIG. 18 is an exploded perspective view schematically illustrating a layer configuration on the front side of the display device in FIG. 17. FIG. 18 is a diagram schematically illustrating a state in which a pointer comes into contact with the display device in FIG. 17. FIG. 20 is a graph showing a relationship between a length s shown in FIG. 4 and a calculated value of a capacitance ratio of the capacitance shown in FIG. 19. FIG. 18 is a graph illustrating an example of a detection result of charges induced on the first electrode in a pressure detection operation when a pseudo finger as a pointer is pressed against a clean touch surface of the display device in FIG. 17. FIG. 18 is a graph illustrating an example of a detection result of charges induced on the second electrode in a pressure detection operation when a pseudo finger as a pointer is pressed against a clean touch surface of the display device in FIG. 17. FIG. 18 is a graph illustrating an example of a result of a mutual capacitance detection operation when a pseudo finger as a pointer is pressed against a clean touch surface of the display device of FIG. 17. FIG. 18 is a graph illustrating an example of a detection result of charges induced on the first electrode in a pressure detection operation when salt water adheres to the touch surface of the display device of FIG. 17. FIG. 18 is a graph illustrating an example of a detection result of charges induced on the second electrode in a pressure detection operation when salt water adheres to the touch surface of the display device of FIG. 17. FIG. 18 is a graph illustrating an example of a result of a mutual capacitance detection operation when salt water adheres to the touch surface of the display device of FIG. 17. FIG. 13 is a partial plan view schematically showing a planar layout of a first electrode and a second electrode of a touch panel according to Embodiment 3 of the present invention. FIG. 28 is a partial plan view schematically showing a configuration of a first metal mesh in a broken line portion MGa in FIG. 27. FIG. 29 is an enlarged view of a broken line portion MGb in FIG. 28. FIG. 28 is a partial plan view schematically showing a configuration of a second metal mesh in a broken line portion MGa in FIG. 27. FIG. 31 is an enlarged view of a broken line portion MGb in FIG. 30. FIG. 28 is a partial plan view schematically showing a configuration of first and second metal meshes in a broken line portion MGa in FIG. 27. FIG. 28 is a graph showing a relationship between a length s shown in FIG. 27 and a calculated value of a capacitance ratio of the capacitance shown in FIG. 6. FIG. 13 is a graph illustrating an example of a detection result of charges induced on a first electrode in a pressure detection operation when a pseudo finger as a pointer is pressed against a clean touch surface of a display device according to Embodiment 3 of the present invention. is there. FIG. 13 is a graph showing an example of a detection result of charges induced on the second electrode in a pressure detection operation when a pseudo finger as a pointer is pressed against a clean touch surface of the display device according to Embodiment 3 of the present invention. is there. FIG. 15 is a graph illustrating an example of a mutual capacitance detection operation result when a pseudo finger as a pointer is pressed against a clean touch surface of the display device according to Embodiment 3 of the present invention. FIG. 15 is a graph illustrating an example of a detection result of charges induced on a first electrode in a pressure detection operation when salt water adheres to a touch surface of a display device according to Embodiment 3 of the present invention. FIG. 15 is a graph illustrating an example of a detection result of charges induced on a second electrode in a pressure detection operation when salt water adheres to a touch surface of a display device according to Embodiment 3 of the present invention. FIG. 14 is a graph illustrating an example of a result of a mutual capacitance detection operation when salt water adheres to the touch surface of the display device according to Embodiment 3 of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.

<First Embodiment>
(Constitution)
FIG. 1 is a partial cross-sectional view schematically showing a configuration of a display device 101 according to the first embodiment. FIG. 2 is an exploded perspective view schematically showing a layer configuration on the front side of the display device 101 (FIG. 1). 3 and 4 are a plan view and a partial plan view schematically showing the configuration of touch panel 1 (FIG. 1). FIG. 5 is a schematic partial sectional view taken along line VV in FIG. FIG. 6 is a diagram schematically illustrating a state where the indicator 900 is in contact with the display device 101 (FIG. 1). FIG. 7 is a block diagram schematically showing a configuration of the display device according to the first embodiment. In FIG. 2, the planar shape of each member is simplified and drawn.

The display device 101 can identify the position pointed by the pointer 900 (FIG. 6). The display device 101 (FIG. 1) has a cover panel 13, a position detection layer LD, and a liquid crystal panel 2 (display panel). The cover panel 13 has a touch surface F1 (first surface) to be designated by the indicator 900, and an inner surface F2 (second surface) opposite to the touch surface F1.

In the present embodiment, the touch panel 1 is constituted by the position detection layer LD and the base substrate 10 supporting the position detection layer LD. The base substrate 10 is transparent and is made of, for example, glass or resin. The touch panel 1 is joined to the inner surface F2 of the cover panel 13 via the adhesive 14 so that the position detection layer LD is located between the cover panel 13 and the base substrate 10. Therefore, the position detection layer LD is provided indirectly on the inner surface F2 of the cover panel 13 via the adhesive 14. Note that the position detection layer LD may be protected by being covered with the protective film 12. The position detection layer LD has a distance t from the touch surface F1.

In order to realize position detection by the projection capacitance method, the position detection layer LD (FIG. 1) includes a plurality of column electrodes 21 (first electrodes), a plurality of row electrodes 31 (second electrodes), and an interlayer. And an insulating film 11 (FIG. 5). The interlayer insulating film 11 insulates between the column electrode 21 and the row electrode 31 in the thickness direction (the vertical direction in FIG. 5). In other words, in a portion where the column electrode 21 and the row electrode 31 overlap in plan view, the space between the column electrode 21 and the row electrode 31 is blocked by the interlayer insulating film 11. In the detection area 9 (FIG. 3), the plurality of column electrodes 21 run in parallel with each other, and the plurality of row electrodes 31 run in parallel with each other. As shown in FIG. 4, the plurality of row electrodes 31 intersect with the plurality of column electrodes 21. In other words, each of the row electrodes 31 crosses the plurality of column electrodes 21, and each of the column electrodes 21 crosses the plurality of row electrodes 31. The position detection layer LD has a configuration in which detection cells CL (FIG. 4) are periodically and repeatedly arranged.

(3) As shown in FIG. 3, specifically, electrodes X0 to X19 are provided as the plurality of column electrodes 21, and electrodes Y0 to Y51 are specifically provided as the plurality of row electrodes 31. In this case, 20 column electrodes and 52 row electrodes 31 are provided, but the numbers of the plurality of column electrodes 21 and row electrodes 31 are not particularly limited and are arbitrary. Each of the column electrodes 21 is connected to the column terminal 4. Each of the column terminals 4 is connected to an external terminal 8 via a lead wire 6. Each of the row electrodes 31 is connected to a row terminal 5. Each of the row terminals 5 is connected to an external terminal 8 via a lead wire 7.

In the present embodiment, the column electrode 21 and the row electrode 31 are made of a transparent conductor, for example, ITO (indium tin oxide). The interlayer insulating film 11 is preferably a transparent film, for example, a silicon nitride film, a silicon oxide film, or an organic film.

The liquid crystal panel 2 (FIG. 1) has the pressure detection electrode 40 facing the position detection layer LD via the gap GP in the thickness direction (vertical direction in the figure). The liquid crystal panel 2 supports the cover panel 13 so that the inner surface F2 of the cover panel 13 can bend toward the gap GP. In order to obtain such a support structure, for example, the liquid crystal panel 2 and the touch panel 1 are joined to each other by the double-sided tape 15 around the gap GP. The gap GP is made of an elastic body, and is preferably made of a gas such as air.

With reference to FIG. 4, the maximum length of a line connecting the column electrode 21 and the row electrode 31 at the shortest distance through an arbitrary point in the interval between the column electrode 21 and the row electrode 31 in plan view is shown. Defined as length s. In the illustrated example, when all points between the plurality of column electrodes 21 and the plurality of row electrodes 31 in plan view are considered, the column electrode 21 and the row electrode 31 pass through the point P1. The length S1 of the line segment connected at the shortest distance corresponds to the length s. In addition, for example, the length S2 of the line segment connecting the column electrode 21 and the row electrode 31 at the shortest distance through the point P2 is shorter than the length S1, and is not the maximum length, and thus corresponds to the length s. do not do. As a relationship between the length s thus defined and the distance t (FIG. 1), the inequality t> s / 2 is satisfied.

Specifically, each of the column electrodes 21 has a plurality of diamond-shaped portions along the extending direction (vertical direction in FIG. 4). In each of the column electrodes 21, adjacent ones of the plurality of diamond-shaped portions are connected to each other in a pattern thinner than the diamond shape. Similarly, each of the row electrodes 31 has a plurality of diamond-shaped portions along the extending direction (lateral direction in FIG. 4). In each of the row electrodes 31, adjacent ones of the plurality of diamond-shaped portions are connected to each other in a pattern thinner than the diamond shape. The diamond-shaped portion of the column electrode 21 and the diamond-shaped portion of the row electrode 31 are separated from each other in plan view. The side of the diamond-shaped portion of the column electrode 21 and the side of the diamond-shaped portion of the row electrode 31 are opposed to each other with an interval therebetween and extend in parallel with each other. Therefore, the position detection layer LD has a parallel region in which the column electrode 21 and the row electrode 31 face each other in parallel in a plan view with an interval therebetween. The distance between the column electrode 21 and the row electrode 31 in the parallel region corresponds to the length S1 = s.

The liquid crystal panel 2 (FIG. 1) has a TFT (Thin Film Transistor) substrate 60, an electrode structure described later, a liquid crystal layer 19, and a color filter substrate 18. The liquid crystal layer 19 is sealed between the TFT substrate 60 and the color filter substrate by using a spacer 61. The TFT substrate 60 is provided with a TFT for each pixel of the liquid crystal panel 2. A polarizing plate 17 is provided on each of the front surface and the rear surface (the upper surface and the lower surface in FIG. 1) of the liquid crystal panel 2. The pressure detection electrode 40 is disposed on the color filter substrate 18 and is separated from the liquid crystal layer 19 by the color filter substrate 18. The pressure detection electrode 40 is electrically connected to a wiring on the TFT substrate 60 via, for example, the silver paste 16. The liquid crystal layer 19 is disposed between the pressure detection electrode 40 and the above-mentioned electrode structure.

The electrode structure is for generating an electric field for controlling the orientation of the liquid crystal layer 19. In the present embodiment, the liquid crystal panel 2 has an electrode structure for generating a lateral electric field on the TFT substrate 60. As a method using the horizontal electric field, an IPS (In Plane Switching) (registered trademark) system may be used. In the example shown in FIG. 1, the case of the FFS system is particularly illustrated. Specifically, the electrode structure has a structure in which the pixel electrode 51, the insulating film 55, and the common electrode 50 are stacked. The pixel electrode 51 is provided in each of a plurality of pixels included in the liquid crystal panel 2 and has a relatively simple planar shape. The common electrode 50 has a comb shape. The orientation of the liquid crystal layer 19 is controlled by the fringe electric field between the common electrode 50 and the pixel electrode 51.

(4) In the horizontal electric field method, when a vertical electric field is generated due to charging of the liquid crystal panel 2, the alignment control of the liquid crystal layer 19 is likely to be adversely affected. Therefore, a structure for removing static electricity from the liquid crystal panel 2 is practically required. For this purpose, a structure capable of applying an external potential between the liquid crystal layer 19 and the gap GP is required. In the present embodiment, since the pressure detecting electrode 40 can be used as this structure, a dedicated structure for removing static electricity can be omitted. Therefore, as a structure to which an external potential can be applied between the liquid crystal layer 19 and the gap GP, only the pressure detection electrode 40 may be provided.

表示 Referring to FIG. 7, display device 101 has excitation signal source 80 and charge detector 82 (first charge detector). The excitation signal source 80 can individually apply an excitation signal to the plurality of column electrodes 21 (first electrodes). Further, the excitation signal source 80 can apply an excitation signal to the pressure detection electrode 40. Further, the excitation signal source 80 operates so that the timing of applying the excitation signal to the plurality of column electrodes 21 and the timing of applying the excitation signal to the pressure detection electrode 40 are different. In addition, when the excitation signal is individually applied to the plurality of column electrodes 21, the pressure detection electrode 40 has a constant potential. On the other hand, when the excitation signal is applied to the pressure detection electrode 40, the plurality of column electrodes 21 and the plurality of row electrodes are used. The excitation signal source 80 operates so that 31 becomes the same constant potential. This operation is realized by being controlled by the control unit 90, for example. The charge detector 82 can individually detect charges induced in the plurality of row electrodes 31 (second electrodes).

In the present embodiment, the display device 101 has a charge detector 81 (second charge detector) as shown in FIG. The charge detector 81 can individually detect charges induced in the plurality of column electrodes 21. When the excitation signal source 80 applies an excitation signal to the pressure detection electrode 40, the charge detector 81 and the charge detector 82 operate. This operation is realized by being controlled by the control unit 90, for example.

The

charge detectors

81 and 82 are, for example, detection integrators. The detection integrator outputs an electric charge charged to the capacitance under the influence of the application of the excitation signal as an analog voltage value (count). This count has a proportional relationship with the electrode capacitance change amount.

(motion)
The detection operation of the display device 101 will be described below mainly with reference to FIG.

圧力 In step S100, pressure is detected. Specifically, first, in step S110, an excitation signal is applied from the excitation signal source 80 to the pressure detection electrode 40. Then, in step S120, charges are detected. Specifically, in step S121, the charges induced in the plurality of column electrodes 21 (first electrodes) are individually detected by the charge detector 81. In step 122, the charges induced in the plurality of row electrodes 31 (second electrodes) are individually detected by the charge detector 82.

In step S200, based on the result of the above pressure detection, control unit 90 determines whether or not indicator 900 (FIG. 6) locally applies pressure on touch surface F1 (FIG. 6). I do. This determination can be made based on, for example, whether or not a peak having a certain intensity is detected, as shown in graphs of FIGS. 11 and 12 described later. The strength may be determined in advance. In that case, the display device 101 may include a storage unit (not shown) for storing the intensity. If the decision result in the step S200 is NO, the process returns to the step S100 again. On the other hand, when the result of the determination is YES, the process proceeds to step S300 described below.

にて In step S300, an operation of position detection by a normal projection-type capacitance system is performed. That is, the mutual capacitance between the column electrode 21 and the row electrode 31 is detected. Specifically, first, in step S310, an excitation signal is individually applied to the plurality of column electrodes 21 (first electrodes) by the excitation signal source 80 while applying a constant potential to the pressure detection electrode 40. Then, in step S320, the charges induced in the plurality of row electrodes 31 are individually detected by the charge detector 82.

Note that step S200 does not necessarily have to be performed. In particular, when it is necessary to detect the non-contact approach of the indicator 900, step S200 may be omitted. When step S200 is omitted, the order of step S100 and step S300 may be reversed.

In step S120, the charges induced on the column electrodes 21 are individually detected, and the charges induced on the row electrodes 31 are individually detected. Therefore, the position of the indicator 900 can be detected not only in step 300 but also in step S100. In step S120, the position need not always be detected. When the position is not detected, the charges induced in the column electrodes 21 do not necessarily need to be individually detected. Further, the charges induced in the row electrodes 31 do not necessarily need to be individually detected. For example, the charge detector 81 may collectively detect the total charges induced in the plurality of row electrodes 31.

(simulation)
FIG. 9 is a graph showing the relationship between the length S1 = s shown in FIG. 4 and the calculated value of the capacitance ratio C3 / (C1 + C2 + C3) between the capacitors C1 to C3 shown in FIG. The capacitance C1 is the capacitance between the pressure detection electrode 40 and the column electrode 21, the capacitance C2 is the capacitance between the pressure detection electrode 40 and the row electrode 31, and the capacitance C3 is the capacitance between the pressure detection electrode 40 and the row electrode 31. This is the capacitance between the pointer and the indicator 900.

In the simulation, the indicator 900 is a conductor having the same size as one detection cell CL. The pitch of the arrangement of the diamond-shaped portions in FIG. 4 is fixed at 5.6 mm. In other words, the size of one detection cell CL is fixed at 5.6 mm square. On the other hand, the thickness c (FIG. 1) of the cover panel 13 is 0.5 mm, 1.0 mm, 1.5 mm, or 2.0 mm. The thickness of the adhesive 14 (FIG. 1) is fixed at 0.2 mm, and the thickness of the protective film 12 (FIG. 1) is negligible, so that the distance t is 0.7 mm, 1.2 mm, 1.7 mm. , Or 2.2 mm. For each distance t, the relationship between the capacity ratio and the length s is calculated. From the result of the calculation shown in FIG. 9, it can be seen that the capacity ratio sharply increases when the length s exceeds the threshold value. This threshold is about twice the distance t. Therefore, when the inequality t> s / 2 is satisfied, the capacitance ratio is sufficiently suppressed.

FIG. 10 shows that when the pressure is detected, that is, when the column electrode 21 and the row electrode 31 are at the same constant potential and an excitation signal is applied to the pressure detection electrode 40, the lines of electric force from the pressure detection electrode 40 FIG. 7 is a schematic diagram showing a state in which the display approaches a pointer 900 above an interval of a length s between row electrodes 31. The above-described capacitance ratio corresponds to the degree of coupling between the pressure detection electrode 40 and the indicator 900 passing between the column electrode 21 and the row electrode 31. Therefore, that the capacitance ratio is sufficiently suppressed means that the electric field between the pressure detection electrode 40 and the indicator 900 is sufficiently shielded by the column electrode 21 and the row electrode 31. On the other hand, when t ≦ s / 2, the shielding is insufficient, and the fringe electric field generated from the pressure detection electrode 40 to the column electrode 21 or the row electrode 31 is preferentially given to the indicator 900 on the touch surface F1. (See arrow RD in the figure).

(4) When the gap GP is made of a solid, the dielectric constant of the gap GP is usually higher than when the gap GP is made of a gas such as air. Therefore, at the time of position detection, the electric field between the column electrode 21 and the row electrode 31 is easily coupled to the pressure detection electrode 40. As a result, the position detection sensitivity decreases. Although it is possible to suppress this decrease in sensitivity by increasing the distance between the column electrode 21 and the row electrode 31, it is necessary to reduce the area of the column electrode 21 or the row electrode 31. As a result of this area reduction, the parallel plate capacitance between the column electrode 21 or the row electrode 31 and the pressure detection electrode 40 decreases, and the ratio of the fringe capacitance component increases. The fringe capacitance has a smaller capacitance change with distance change than the parallel plate capacitance. This means that the change in the capacitance between the column electrode 21 or the row electrode 31 and the pressure detection electrode 40 becomes slow with respect to the change in the distance. That is, the pressure detection sensitivity is reduced. Therefore, it is desirable that the gap GP is made of a gas such as air rather than a solid.

(Operation experiment when the touch surface is clean)
The following describes experimental results on operations of pressure detection (corresponding to step S100 (FIG. 8)) and mutual capacitance detection (corresponding to step S300 (FIG. 8)) when the touch surface F1 is clean. The thickness c (FIG. 1) of the cover panel 13 was 1 mm, the thickness of the adhesive 14 (FIG. 1) was 0.2 mm, and the length s (FIG. 4) was 0.5 mm. As the indicator 900, a grounded pseudo finger was used with a load of 100 g weight.

FIG. 11 shows an example of the output count of each of the detection integrators of the electrodes X0 to X19 constituting the column electrode 21 (first electrode) in the pressure detection operation when the pseudo finger is pressed against the clean touch surface F1. FIG. FIG. 12 shows an example of the output count of the detection integrator of each of the electrodes Y0 to Y51 constituting the row electrode 31 (second electrode) in the pressure detection operation when the pseudo finger is pressed against the clean touch surface F1. FIG. A pulse as an excitation signal was input to the pressure detection electrode 40 (corresponding to step S110 (FIG. 8)). Then, the count of the detection integrator connected to each of the electrodes X0 to X19 constituting the column electrode 21 (first electrode) was detected (corresponding to step S121 (FIG. 8)). In addition, the count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31 (second electrode) is detected (step S122 (step S122 (FIG. 8)). A distinct peak in the count value was detected, the significant magnitude of the count indicates the presence of pressure, and the coordinates of the peak indicate the location of the pseudo finger.

FIG. 13 is a graph showing an example of a mutual capacitance detection operation result when a pseudo finger is pressed against a clean touch surface. Pulses as excitation signals were sequentially input to the electrodes X0 to X19 constituting the column electrode 21 (first electrode) (FIG. 8: step S310). The count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31 (second electrode) is detected in a time-division manner for each pulse (step S310 (FIG. 8)). As a result of the detection, a clear peak at a significant count value was detected. Since the count has a significant size, the approach or contact of the pseudo finger is known, and the position of the pseudo finger is known from the coordinates of the peak.

(Operation experiment when the touch surface is not clean)
The following describes experimental results on operations of pressure detection (corresponding to step S100 (FIG. 8)) and mutual capacitance detection (corresponding to step S300 (FIG. 8)) when the touch surface F1 is not clean. Unlike the above-described operation experiment in the case where the touch surface is clean, in this experiment, the pseudo finger did not touch the touch surface F1, and instead, salt water was attached to the touch surface F1. The other conditions are the same as those in the above-described operation experiment when the touch surface is clean.

FIG. 14 is a graph showing an example of output counts of the detection integrators of the electrodes X0 to X19 constituting the column electrode 21 (first electrode) in the pressure detection operation when salt water adheres to the touch surface F1. is there. FIG. 15 is a graph showing an example of the output count of each of the detection integrators of the electrodes Y0 to Y51 constituting the row electrode 31 (second electrode) in the pressure detection operation when salt water adheres to the touch surface F1. is there. A pulse as an excitation signal was input to the pressure detection electrode 40 (corresponding to step S110 (FIG. 8)). Then, the count of the detection integrator connected to each of the electrodes X0 to X19 constituting the column electrode 21 (first electrode) was detected (corresponding to step S121 (FIG. 8)). Further, the count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31 (second electrode) is detected (step S122 (step S122 (FIG. 8)). As a result of the detection, FIG. 12 and only the counts close to the noise level were detected, unlike the detection results of Fig. 12. Since the counts do not have a significant magnitude, it can be seen that there is no pressure from the indicator. Is suppressed on the detection result because the inequality t> s / 2 is satisfied and the electric field between the pressure detection electrode 40 and the indicator 900 is satisfied, as described in the above description of the simulation. Is sufficiently shielded by the column electrode 21 and the row electrode 31.

FIG. 16 is a graph showing an example of a mutual capacitance detection operation result when salt water adheres to the touch surface F1. Pulses as excitation signals were sequentially input to the electrodes X0 to X19 constituting the column electrode 21 (first electrode) (FIG. 8: step S310). The count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31 (second electrode) is detected in a time-division manner for each pulse (step S310 (FIG. 8)). As a result, a significant count larger than the noise level was detected. Since the count has a significant size, there is a possibility that the detection result may be mistaken for the approach or contact of the pseudo finger. When the execution of step S300 (FIG. 8) is restricted by step S200 (FIG. 8), such erroneous recognition can be avoided.

If the touch surface F1 is not clean, as shown in FIG. 16, the count due to the indicator, that is, noise increases, so that position detection based on mutual capacitance detection may be difficult. In such a case, position detection (see FIGS. 11 and 12) accompanying pressure detection may be performed without depending on mutual capacitance detection. In this case, detection of multi-touch is difficult, but detection of single touch is possible. Further, as shown in FIGS. 11 and 12, by detecting the counts of the electrodes X0 to X19 and the electrodes Y0 to Y51, the position coordinates of the pointer can be detected.

(effect)
According to the present embodiment, as described in the description of the simulation, since the inequality t> s / 2 is satisfied, the gap between the column electrode 21 and the row electrode between the pressure detection electrode 40 and the touch surface F1 is satisfied. 31 are sufficiently shielded. Therefore, it is possible to prevent the pressure detection from being disturbed by the foreign matter on the touch surface F1.

The length s satisfying the inequality t> s / 2 is equal to the length of the column electrode 21 in the parallel region (the region where the side of the column electrode 21 and the side of the row electrode 31 face in parallel in FIG. 4 via the dimension s). The distance from the row electrode 31 may be used. Accordingly, the column electrode 21 and the row electrode 31 sufficiently shield the space between the pressure detection electrode 40 and the touch surface F1 over the entire parallel region. Therefore, it is more sufficiently prevented that the pressure detection is disturbed by the foreign matter on the touch surface F1.

(4) When the liquid crystal panel 2 is a horizontal electric field type liquid crystal panel, the orientation of the liquid crystal layer 19 controlled by the horizontal electric field is easily disturbed by a vertical electric field generated due to charging of the liquid crystal panel 2. Therefore, a structure for removing static electricity from the liquid crystal panel 2 is required. For this purpose, a structure capable of applying an external potential between the liquid crystal layer 19 and the gap GP is required. According to the present embodiment, by using the pressure detection electrode 40 as this structure, a dedicated structure for removing static electricity can be omitted. Thereby, the configuration of the liquid crystal panel 2 can be simplified.

In the pressure detection operation (FIG. 8: step S100), not the charge of the pressure detection electrode 40 provided on the liquid crystal panel 2 but the charge of the column electrode 21 and the row electrode 31 which are arranged relatively far from the liquid crystal panel 2. Is detected. Thereby, the influence of the electromagnetic noise generated from the liquid crystal panel 2 on the detection can be suppressed. When it is not necessary to consider this effect, an excitation signal may be applied to the column electrode 21 and the row electrode 31 to detect the charge of the pressure detection electrode 40.

(4) When the excitation signal source 80 applies an excitation signal to the pressure detection electrode 40, the charge detector 81 and the charge detector 82 may operate. With this operation, the position indicated by the indicator 900 can be specified. Specifying the position by this method is not easily disturbed by a foreign substance on the touch surface F1. Therefore, position detection can be performed even in a state in which foreign matter has adhered to the touch surface F1.

<Embodiment 2>
(Constitution)
FIG. 17 is a partial cross-sectional view schematically showing a configuration of a display device 102 according to the second embodiment. FIG. 18 is an exploded perspective view schematically showing a layer configuration on the front side of display device 102 (FIG. 17). FIG. 19 is a diagram schematically illustrating a state in which the indicator 900 is in contact with the display device 102 (FIG. 17).

The structure of the touch panel 1 included in the display device 102 is simplified by omitting the base substrate 10 and the adhesive 14 (FIG. 1: Embodiment 1). To achieve this, the position detection layer LD is provided directly on the inner surface F2 of the cover panel 13. The remaining configuration is substantially the same as the configuration of the above-described first embodiment. Therefore, the same or corresponding elements are denoted by the same reference characters, and description thereof will not be repeated.

(simulation)
FIG. 20 is a graph showing the relationship between the length S1 = s shown in FIG. 4 and the calculated value of the capacitance ratio C3 / (C1 + C2 + C3) between the capacitors C1 to C3 shown in FIG. As in the first embodiment, the capacitance C1 is the capacitance between the pressure detection electrode 40 and the column electrode 21, and the capacitance C2 is the capacitance between the pressure detection electrode 40 and the row electrode 31. C3 is the capacitance between the pressure detection electrode 40 and the indicator 900. In this simulation, the indicator 900 is a conductor having the same size as one detection cell CL. The pitch of the arrangement of the diamond-shaped portions in FIG. 4 is fixed at 5.6 mm. In other words, the size of one detection cell CL is fixed at 5.6 mm square. On the other hand, the thickness c (FIG. 17) of the cover panel 13 is 0.5 mm, 1.0 mm, 1.5 mm, or 2.0 mm. In the present embodiment, the thickness c corresponds to the distance t. For each distance t, the relationship between the capacity ratio and the length s is calculated. From the result of the calculation shown in FIG. 20, it can be seen that the capacity ratio sharply increases when the length s exceeds the threshold. This threshold is about twice the distance t. Therefore, as in the first embodiment, when the inequality t> s / 2 is satisfied, the capacitance ratio is sufficiently suppressed. When the capacitance ratio is sufficiently suppressed, it means that the electric field between the pressure detection electrode 40 and the indicator 900 is sufficiently shielded by the column electrode 21 and the row electrode 31.

(Operation experiment when the touch surface is clean)
The following describes experimental results on operations of pressure detection (corresponding to step S100 (FIG. 8)) and mutual capacitance detection (corresponding to step S300 (FIG. 8)) when the touch surface F1 is clean. The thickness c (FIG. 17) of the cover panel 13 was 1 mm, and the length s (FIG. 4) was 0.5 mm. As the indicator 900, a grounded pseudo finger was used with a load of 100 g weight.

FIG. 21 shows an example of the output count of the detection integrator of each of the electrodes X0 to X19 constituting the column electrode 21 (first electrode) in the pressure detection operation when the pseudo finger is pressed against the clean touch surface F1. FIG. FIG. 22 shows an example of an output count of each of the detection integrators of the electrodes Y0 to Y51 constituting the row electrode 31 (second electrode) in the pressure detection operation when the pseudo finger is pressed against the clean touch surface F1. FIG. A pulse as an excitation signal was input to the pressure detection electrode 40 (corresponding to step S110 (FIG. 8)). Then, the count of the detection integrator connected to each of the electrodes X0 to X19 constituting the column electrode 21 (first electrode) was detected (corresponding to step S121 (FIG. 8)). In addition, the count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31 (second electrode) is detected (step S122 (step S122 (FIG. 8)). A distinct peak in the count value was detected, the significant magnitude of the count indicates the presence of pressure, and the coordinates of the peak indicate the location of the pseudo finger.

FIG. 23 is a graph showing an example of the result of the mutual capacitance detection operation when a pseudo finger is pressed against a clean touch surface. Pulses as excitation signals were sequentially input to the electrodes X0 to X19 constituting the column electrode 21 (first electrode) (FIG. 8: step S310). The count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31 (second electrode) is detected in a time-division manner for each pulse (step S310 (FIG. 8)). As a result of the detection, a clear peak at a significant count value was detected. Since the count has a significant size, the approach or contact of the pseudo finger is known, and the position of the pseudo finger is known from the coordinates of the peak.

FIG. 24 is a graph showing an example of the output count of the detection integrator of each of the electrodes X0 to X19 constituting the column electrode 21 (first electrode) in the pressure detection operation when salt water adheres to the touch surface F1. is there. FIG. 25 is a graph showing an example of an output count of each of the detection integrators of the electrodes Y0 to Y51 constituting the row electrode 31 (second electrode) in the pressure detection operation when salt water adheres to the touch surface F1. is there. A pulse as an excitation signal was input to the pressure detection electrode 40 (corresponding to step S110 (FIG. 8)). Then, the count of the detection integrator connected to each of the electrodes X0 to X19 constituting the column electrode 21 (first electrode) was detected (corresponding to step S121 (FIG. 8)). Further, the count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31 (second electrode) is detected (step S122 (step S122 (FIG. 8)). As a result of the detection, FIG. 22 and only the count close to the noise level was detected, unlike the detection result of Fig. 22. Since the count does not have a significant size, it can be seen that there is no pressure from the indicator. Is suppressed on the detection result because the inequality t> s / 2 is satisfied and the electric field between the pressure detection electrode 40 and the indicator 900 is satisfied, as described in the above description of the simulation. Is sufficiently shielded by the column electrode 21 and the row electrode 31.

FIG. 26 is a graph showing an example of the result of the mutual capacitance detection operation when salt water adheres to the touch surface F1. Pulses as excitation signals were sequentially input to the electrodes X0 to X19 constituting the column electrode 21 (first electrode) (FIG. 8: step S310). The count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31 (second electrode) is detected in a time-division manner for each pulse (step S310 (FIG. 8)). As a result, a significant count larger than the noise level was detected. Since the count has a significant size, there is a possibility that the detection result may be mistaken for the approach or contact of the pseudo finger. When the execution of step S300 (FIG. 8) is restricted by step S200 (FIG. 8), such erroneous recognition can be avoided.

When the touch surface F1 is not clean, as shown in FIG. 26, the count not caused by the pointer, that is, the noise increases, so that the position detection based on the mutual capacitance detection may be difficult. In such a case, position detection accompanying the pressure detection (see FIGS. 21 and 22) may be performed without depending on the mutual capacitance detection. In this case, detection of multi-touch is difficult, but detection of single touch is possible. Further, as shown in FIG. 21 and FIG. 22, it is possible to detect the position coordinates of the pointer by detecting the count of each of the electrodes X0 to X19 and the electrodes Y0 to Y51.

<Embodiment 3>
In the display device of the present embodiment, a column electrode and a row electrode made of a metal mesh are used instead of the column electrode 21 and the row electrode 31 made of a transparent conductor (FIG. 4: Embodiment 1). Other configurations are almost the same as the configuration of the first embodiment described above, and therefore, the configuration of the column wiring and the row wiring will be mainly described below.

FIG. 27 is a partial plan view schematically showing a planar layout of column electrodes 21M (first electrodes) and row electrodes 31M (second electrodes) of touch panel 1 in the third embodiment. In FIG. 27, the outer edges of each of the column electrode 21M and the row electrode 31M are shown, and the fine structure of each of the column electrode 21M and the row electrode 31M, specifically, a mesh pattern (FIGS. 28 to 32) ) Are not shown.

In the present embodiment, column electrode 21M and row electrode 31M are provided instead of column electrode 21 and row electrode 31 (FIG. 4: Embodiment 1). In the planar layout, an isolation region RS insulated from both the column electrode 21M and the row electrode 31M is provided between the column electrode 21M and the row electrode 31M. Similar to the case of the first embodiment (FIG. 4), any point in the interval (corresponding to the isolation region RS) between the plurality of column electrodes 21M and the plurality of row electrodes 31M in plan view (FIG. 27). The maximum length of a line segment connecting the column electrode 21M and the row electrode 31M at the shortest distance through is defined as the length s. In the illustrated example, when all points between the plurality of column electrodes 21M and the plurality of row electrodes 31M in plan view are considered, the length S1 corresponds to the length s. Note that the length S2 is shorter than the length S1, and is not the maximum length, and thus does not correspond to the length s. As a relationship between the length s thus defined and the distance t (FIG. 1), the inequality t> s / 2 is satisfied.

In the present embodiment, the position detection layer LD (FIG. 1) has a parallel region in which the column electrode 21M and the row electrode 31M face each other in parallel in a plan view with an interval therebetween (for example, in FIG. 27). (See the area indicated by the broken line MGa). The distance between the column electrode 21M and the row electrode 31M in the parallel region corresponds to the length S1 = s.

In the present embodiment, the position detection layer LD (FIG. 1) includes a first metal mesh 20 (described later with reference to FIG. 28) and a second A metal mesh 30 (described later with reference to FIG. 30). These metal meshes are members having a mesh pattern made of a metal such as aluminum. By having a mesh pattern, a member having a light-transmitting property when viewed macroscopically can be formed using a metal material having no light-transmitting property. Hereinafter, the configuration of these metal meshes will be described.

FIG. 28 is a partial plan view schematically showing the configuration of the first metal mesh 20 in the broken line portion MGa in FIG. FIG. 29 is an enlarged view of a broken line portion MGb in FIG. Note that the difference in the thickness of the solid line in each of FIG. 28 and FIG. 29 is for making the figure easier to see, and does not mean the difference in the thickness of the mesh pattern. The mesh pattern preferably has a uniform thickness. The small circles indicated by broken lines in FIG. 29 are drawn for explanation, and do not represent the configuration. In FIG. 29, the second metal mesh 30 is shown by a two-dot chain line for reference.

The first metal mesh 20 has a first mesh pattern. The first mesh pattern has a two-dimensional periodic structure (first periodic structure) in plan view. In the example shown in FIG. 28, the first mesh pattern has a period P1 and a period P2 along the vertical direction and the horizontal direction, respectively. The period P1 and the period P2 may be different from each other, or may be the same as each other. The first mesh pattern has a locally broken portion. The “disconnection portion” is a portion where the fine line structure of the mesh pattern is locally divided. Specifically, a disconnection portion 21c (first disconnection portion), a disconnection portion 22c, and a disconnection portion 23c are provided.

The first metal mesh 20 includes a plurality of column electrodes 21M, a plurality of first dummy electrodes 22, and a plurality of first floating electrodes 23. The first dummy electrode 22 overlaps with the row electrode 31M (described later with reference to FIG. 30) in plan view. However, the first dummy electrode 22 is not provided in a region where the row electrode 31M and the column electrode 21M overlap in plan view. The first floating electrode 23 is arranged between the column electrode 21M and the first dummy electrode 22.

The disconnection portion 21c insulates the first dummy electrode 22 and the first floating electrode 23 from the column electrode 21M. In other words, the disconnection portion 21c insulates the first metal mesh 20 from the column electrode 21M and a portion other than the column electrode 21M. The disconnection portion 22c insulates the first floating electrode 23 from the first dummy electrode 22. The disconnection portion 23c divides each of the first floating electrodes 23 into a plurality of portions that are insulated from each other.

Note that, as shown in FIG. 29, a minute pattern (a pattern shown in a small circle in the figure) apart from the first mesh pattern may be provided at a broken portion of the first mesh pattern. . This minute pattern may be formed from the same material as the material of the first metal mesh 20. This fine pattern is preferably a linear pattern extending in a direction different from the original direction of the first mesh pattern, and the linear pattern may be a direction orthogonal to the original direction of the first mesh pattern. preferable. Further, it is preferable that the length of the linear pattern is equal to the length at which the first mesh pattern is divided by the disconnection portion.

FIG. 30 is a partial plan view schematically showing the configuration of the second metal mesh 30 in the broken line portion MGa in FIG. FIG. 31 is an enlarged view of a broken line portion MGb in FIG. Note that the difference in thickness between the solid lines in each of FIGS. 30 and 31 is for facilitating viewing of the drawing, and does not mean the difference in thickness between the mesh patterns. The mesh pattern preferably has a uniform thickness. Also, the broken small circles in FIG. 31 are drawn for explanation, and do not represent the configuration. In FIG. 31, the first metal mesh 20 is shown by a two-dot chain line for reference.

The second metal mesh 30 faces the first metal mesh 20 via the interlayer insulating film 11 (see FIG. 2) in the thickness direction. In the present embodiment, the interlayer insulating film 11 may be provided over the entire detection area 9 (FIG. 3). The second metal mesh 30 has a second mesh pattern. The second mesh pattern has a two-dimensional periodic structure (second periodic structure) in plan view. In the example shown in FIG. 30, the second mesh pattern has a period P1 and a period P2 along the vertical direction and the horizontal direction, respectively. That is, the second mesh pattern has the same two periods as the first mesh pattern. However, as described later, there is a phase shift between the arrangement of the first mesh pattern and the arrangement of the second mesh pattern. The second mesh pattern has a locally broken portion. Specifically, a disconnection portion 31c (second disconnection portion), a disconnection portion 32c, and a disconnection portion 33c are provided.

The second metal mesh 30 includes a plurality of row electrodes 31M, a plurality of second dummy electrodes 32, and a plurality of second floating electrodes 33. The second dummy electrode 32 overlaps the column electrode 21M (FIG. 28) in plan view. However, the second dummy electrode 32 is not provided in a region where the column electrode 21M and the row electrode 31M overlap in plan view. The second floating electrode 33 is disposed between the row electrode 31M and the second dummy electrode 32.

The disconnection part 31c insulates the second dummy electrode 32 and the second floating electrode 33 from the row electrode 31M. In other words, the disconnection portion 31c insulates the second metal mesh 30 from the row electrode 31M and a portion other than the row electrode 31M. The disconnection part 32 c insulates the second floating electrode 33 from the second dummy electrode 32. The disconnection portion 33c divides each of the second floating electrodes 33 into a plurality of portions that are insulated from each other.

In addition, as shown in FIG. 31, a minute pattern (a pattern shown in a small circle in the figure) apart from the second mesh pattern may be provided in the broken portion of the second mesh pattern. . This minute pattern may be formed from the same material as the material of the second metal mesh 30. This fine pattern is preferably a linear pattern extending in a direction different from the original direction of the second mesh pattern, and the linear pattern is preferably a direction orthogonal to the original direction of the second mesh pattern. preferable. Further, it is preferable that the length of the linear pattern is equal to the length at which the second mesh pattern is divided by the disconnection portion.

FIG. 32 is a partial plan view schematically showing the configuration of the first metal mesh 20 and the second metal mesh 30 in the broken line portion MGa in FIG. The first metal mesh 20 is represented by a relatively thick line, and the second metal mesh 30 is represented by a relatively thin line, for easy understanding of the drawing. In other words, the periodic structure of the first mesh pattern of the first metal mesh 20, that is, the first periodic structure, corresponds to the thick line in the drawing, and the period of the second mesh pattern of the second metal mesh 30. The structure, that is, the second periodic structure corresponds to the thin line in the figure. As shown in FIG. 32, the second periodic structure is complementary to the first periodic structure. In other words, a phase shift is provided between the first periodic structure and the second periodic structure. This phase shift is preferably about a half cycle as shown.

として As an example of the present embodiment, the width of the fine metal wire constituting the first and second mesh patterns is 3 μm. The break interval between the break portions of the first and second mesh patterns is 10 μm. The width of the first floating electrode 23 (the horizontal dimension in FIG. 28) is 800 μm. Each of the periods P1 and P2 (FIGS. 28, 30 and 32) is 400 μm. The thickness of the base substrate 10 (FIG. 1) is 0.9 mm.

(simulation)
FIG. 33 is a graph showing the relationship between the length s shown in FIG. 27 and the calculated value of the capacitance ratio of the capacitance similar to the capacitance shown in FIG. In this simulation, the capacitance C1 is the capacitance between the pressure detection electrode 40 and the column electrode 21M, the capacitance C2 is the capacitance between the pressure detection electrode 40 and the row electrode 31M, and the capacitance C3 is The capacitance between the pressure detection electrode 40 and the indicator 900. The thickness c (FIG. 1) of the cover panel 13 is 0.5 mm, 1.0 mm, 1.5 mm, or 2.0 mm. The thickness of the adhesive 14 (FIG. 1) is fixed at 0.2 mm, and the thickness of the protective film 12 (FIG. 1) is negligible, so that the distance t is 0.7 mm, 1.2 mm, 1.7 mm. , Or 2.2 mm. For each distance t, the relationship between the capacity ratio and the length s is calculated. From the result of the calculation shown in FIG. 33, it can be seen that the capacity ratio sharply increases when the length s exceeds the threshold value. This threshold is about twice the distance t. Therefore, when the inequality t> s / 2 is satisfied, the capacitance ratio is sufficiently suppressed. That the capacitance ratio is sufficiently suppressed means that the electric field between the pressure detection electrode 40 and the indicator 900 is sufficiently shielded by the column electrode 21M and the row electrode 31M.

(Operation experiment when the touch surface is clean)
The following describes experimental results on operations of pressure detection (corresponding to step S100 (FIG. 8)) and mutual capacitance detection (corresponding to step S300 (FIG. 8)) when the touch surface F1 is clean. The thickness c (FIG. 1) of the cover panel 13 was 1 mm, the thickness of the adhesive 14 (FIG. 1) was 0.2 mm, and the length s (FIG. 27) was 0.5 mm. As the indicator 900, a grounded pseudo finger was used with a load of 100 g weight.

FIG. 34 shows an example of the output count of each of the detection integrators of the electrodes X0 to X19 constituting the column electrode 21M (first electrode) in the pressure detection operation when the pseudo finger is pressed against the clean touch surface F1. FIG. FIG. 35 shows an example of the output count of each detection integrator of the electrodes Y0 to Y51 constituting the row electrode 31M (second electrode) in the pressure detection operation when the pseudo finger is pressed against the clean touch surface F1. FIG. A pulse as an excitation signal was input to the pressure detection electrode 40 (corresponding to step S110 (FIG. 8)). Then, the count of the detection integrator connected to each of the electrodes X0 to X19 constituting the column electrode 21M (first electrode) was detected (corresponding to step S121 (FIG. 8)). Further, the count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31M (second electrode) was detected (step S122 (step S122 (FIG. 8)). A distinct peak in the count value was detected, the significant magnitude of the count indicates the presence of pressure, and the coordinates of the peak indicate the position of the pseudo finger.

FIG. 36 is a graph showing an example of the result of the mutual capacitance detection operation when a pseudo finger is pressed against a clean touch surface. Pulses as excitation signals were sequentially input to the electrodes X0 to X19 constituting the column electrode 21M (first electrode) (FIG. 8: step S310). The count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31M (second electrode) is detected in a time-division manner for each pulse (step S310 (FIG. 8)). As a result of the detection, a clear peak at a significant count value was detected. Since the count has a significant size, the approach or contact of the pseudo finger is known, and the position of the pseudo finger is known from the coordinates of the peak.

FIG. 37 is a graph showing an example of output counts of the detection integrators of the electrodes X0 to X19 constituting the column electrode 21M (first electrode) in the pressure detection operation when salt water adheres to the touch surface F1. is there. FIG. 38 is a graph showing an example of the output count of each of the detection integrators of the electrodes Y0 to Y51 constituting the row electrode 31M (second electrode) in the pressure detection operation when salt water adheres to the touch surface F1. is there. A pulse as an excitation signal was input to the pressure detection electrode 40 (corresponding to step S110 (FIG. 8)). Then, the count of the detection integrator connected to each of the electrodes X0 to X19 constituting the column electrode 21M (first electrode) was detected (corresponding to step S121 (FIG. 8)). Further, the count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31M (second electrode) is detected (step S122 (step S122 (FIG. 8)). As a result of the detection, FIG. 35, only counts close to the noise level were detected, indicating that there was no pressure from the indicator since the counts did not have a significant magnitude. Is suppressed on the detection result because the inequality t> s / 2 is satisfied and the electric field between the pressure detection electrode 40 and the indicator 900 is satisfied, as described in the above description of the simulation. Is sufficiently shielded by the column electrodes 21M and the row electrodes 31M.

FIG. 39 is a graph illustrating an example of a result of the mutual capacitance detection operation when salt water adheres to the touch surface F1. Pulses as excitation signals were sequentially input to the electrodes X0 to X19 constituting the column electrode 21M (first electrode) (FIG. 8: step S310). The count of the detection integrator connected to each of the electrodes Y0 to Y51 as the row electrode 31M (second electrode) is detected in a time-division manner for each pulse (step S310 (FIG. 8)). As a result, a significant count larger than the noise level was detected. Since the count has a significant size, there is a possibility that the detection result may be mistaken for the approach or contact of the pseudo finger. When the execution of step S300 (FIG. 8) is restricted by step S200 (FIG. 8), such erroneous recognition can be avoided.

If the touch surface F1 is not clean, as shown in FIG. 39, the count that is not caused by the indicator, that is, the noise increases, so that position detection based on mutual capacitance detection may be difficult. In such a case, position detection accompanying the pressure detection (see FIGS. 34 and 35) may be performed without depending on the mutual capacitance detection. In this case, detection of multi-touch is difficult, but detection of single touch is possible. Further, as shown in FIGS. 34 and 35, the position coordinates of the pointer can be detected by detecting the count of each of the electrodes X0 to X19 and the electrodes Y0 to Y51.

(effect)
According to the present embodiment, substantially the same effects as in the first embodiment can be obtained. Note that the position detection layer LD having the first metal mesh 20 and the second metal mesh 30 of the present embodiment may be applied to the second embodiment instead of the first embodiment. Almost the same effects as those of No. 2 can be obtained.

According to the present embodiment, a metal material is used as a material for the row electrode and the column electrode, instead of a transparent conductive material. Thereby, the electric resistance of the electrode can be reduced. Therefore, the speed of the detection operation can be increased. In order to confirm this, the inventor conducted an experiment in which each of Step S100 and Step S300 shown in FIG. 8 was performed once. As a result, the operation time in the third embodiment was reduced to about 1/3 of the operation time in the first embodiment.

The periodic structure of the second mesh pattern of the second metal mesh 30, that is, the second periodic structure is complementary to the periodic structure of the first mesh pattern of the first metal mesh 20, that is, the first periodic structure. It is a target. Thereby, the reflectance in the detection area 9 (FIG. 3) is made uniform. Therefore, it is possible to make the first metal mesh 20 and the second metal mesh 30 less visible.

Preferably, as shown in FIGS. 29 and 31, a minute pattern is provided at a disconnection portion of the first and second mesh patterns. Accordingly, it is possible to prevent the translucency of the touch panel 1 from locally increasing in the disconnection portion. Therefore, the disconnection portion can be made hard to be visually recognized.

In the present invention, it is possible to freely combine the embodiments or appropriately modify or omit the embodiments within the scope of the invention. Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that innumerable modifications that are not illustrated can be assumed without departing from the scope of the present invention.

CL detection cell, F1 touch surface (first surface), F2 inner surface (second surface), GP gap, LD position detection layer, RS separation region, X0 to X19, Y0 to Y51 electrodes, 1 touch panel, 2 liquid crystal panel (display) Panel), 9 detection area, 10 base substrate, 11 interlayer insulating film, 12 protective film, 13 cover panel, 14 adhesive, 15 double-sided tape, 16 silver paste, 17 polarizing plate, 18 color filter substrate, 19 liquid crystal layer, 20 First metal mesh, 21, 21M {column electrode (first electrode), 21c} disconnection part (first disconnection part), 22c, 23c {disconnection part, 31c} disconnection part (second disconnection part), 32c, 33c {disconnection part, 22} th 1 dummy electrode, 23 {first floating electrode, 30 {second metal mesh, 31, 31M} row electrode (second electrode), 2 second dummy electrode, 33 second floating electrode, 40 pressure sensing electrode, 50 common electrode, 51 pixel electrode, 55 insulating film, 60 TFT substrate, 80 excitation signal source, 81, 82 charge detector, 90 control section, 101 , 102 ° display device, 900 ° indicator.

Claims

A display device capable of specifying a position pointed by a pointer,
A cover panel having a first surface to be indicated by the indicator, and a second surface opposite to the first surface;
A position detection layer provided directly or indirectly on the second surface of the cover panel and having a distance t from the first surface;
Comprising, the position detection layer,
A plurality of first electrodes running side by side with each other;
A plurality of second electrodes running parallel to each other and intersecting with the plurality of first electrodes;
An interlayer insulating film insulating between the plurality of first electrodes and the plurality of second electrodes in a thickness direction;
The display device further includes a pressure detection electrode facing the position detection layer via a gap in a thickness direction, so that the second surface of the cover panel can bend toward the gap. A display panel supporting the cover panel;
With
The maximum length of a line connecting the first electrode and the second electrode at the shortest distance through an arbitrary point in the interval between the plurality of first electrodes and the plurality of second electrodes in plan view is set to be long. When defined as s
t> s / 2
Is satisfied, the display device.
The position detection layer has a parallel region in which the plurality of first electrodes and the plurality of second electrodes face in parallel with an interval in plan view,
The display device according to claim 1, wherein the length s is a distance between the plurality of first electrodes and the plurality of second electrodes in the parallel region.
The display panel includes an electrode structure that generates a lateral electric field, and a liquid crystal layer provided between the electrode structure and the pressure detection electrode,
Between the liquid crystal layer and the gap, as a structure to which an external potential can be applied, only the pressure detection electrode is provided,
The display device according to claim 1.
A first charge detector capable of individually detecting charges induced in the plurality of second electrodes;
An excitation signal can be individually applied to the plurality of first electrodes, an excitation signal can be applied to the pressure detection electrode, and a timing of applying the excitation signal to the plurality of first electrodes and the pressure detection electrode An excitation signal source that operates so that the timing of applying the excitation signal to the
The display device according to any one of claims 1 to 3, further comprising:
At the timing of individually applying an excitation signal to the plurality of first electrodes, the pressure detection electrode becomes a constant potential, and at the timing of applying an excitation signal to the pressure detection electrode, the plurality of first electrodes and the plurality of second electrodes are applied. The display device according to claim 4, wherein the excitation signal source operates so that the constant potentials are equal to each other.
A second charge detector that can individually detect charges induced in the plurality of first electrodes,
When the excitation signal source applies an excitation signal to the pressure detection electrode, the first charge detector and the second charge detector operate.
The display device according to claim 4.
The position detection layer,
A first metal mesh having a first mesh pattern;
A second metal mesh facing the first metal mesh via the interlayer insulating film in a thickness direction and having a second mesh pattern;
Including
The first mesh pattern has a first periodic structure in a plan view, and locally has a first disconnection portion,
The second mesh pattern has a second periodic structure in a plan view and locally has a second disconnection portion, and the second periodic structure is different from the first periodic structure. And complementary,
The first metal mesh,
The plurality of first electrodes;
A plurality of first dummy electrodes overlapping with the plurality of second electrodes in plan view and insulated from the plurality of first electrodes by the first disconnection portion;
A plurality of first floating electrodes disposed between the plurality of first electrodes and the plurality of first dummy electrodes and insulated from the plurality of first electrodes by the first disconnection;
Including
The second metal mesh,
The plurality of second electrodes;
A plurality of second dummy electrodes overlapping with the plurality of first electrodes in plan view and insulated from the plurality of second electrodes by the second disconnection portion;
A plurality of second floating electrodes disposed between the plurality of second electrodes and the plurality of second dummy electrodes and insulated from the second electrodes by the second disconnection;
including,
The display device according to claim 1.