JP2011039851A - Touch panel, display device with touch detection function, adapter for touch panel and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch panel which prevents scratches on a surface thereof, ensures strength, and allows soft touch, and to provide a display device with a touch detection function, an adapter for touch panels and electronic equipment. <P>SOLUTION: The touch panel includes a first substrate (array substrate 11) and a second substrate (color filter substrate 12) each of which has electrodes formed on one surface thereof and are spaced from each other so that the surfaces having electrodes formed thereon face each other, and a tabular elastic sheet 16 spaced from the second substrate on the side opposite to the surface having the electrode formed thereon of the second substrate and has elasticity. An external force can be concentrated on a small contact area when being transmitted from the elastic sheet 16 to the color filter substrate 12, and a pressure P applied to a surface (the color filter substrate 12) of a touch panel is increased, thereby enabling touch detection with a weaker external force F than when no gap 15 is formed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a touch panel that allows a user to input information by touching with a finger or the like, and in particular, a touch panel that detects a touch based on bending caused by the contact, a display device with a touch detection function, an adapter for touch panel, and an electronic device About.

  In recent years, a touch detection device called a touch panel is mounted on a display device such as a liquid crystal display device, and various button images are displayed on the display device, thereby enabling information input in place of a normal mechanical button. Display devices are attracting attention. Since a display device having a touch panel does not require an input device such as a keyboard, a mouse, or a keypad, the use of the display device tends to increase in a portable information terminal such as a mobile phone as well as a computer.

  There are various types of touch panel methods, and one of them is a method of detecting the deflection of the touch panel caused by contact (external force) of a finger or the like. For example, a resistive film type, an electrode contact type, a capacitance type, etc. belong to this type. Resistive film type is obtained by obtaining the resistance voltage division ratio resulting from the resistance components of the two resistive films when the electrodes of the two opposing resistive films that make up the touch panel come into contact with each other by external force. For example, it is attached on a display device. The electrode contact type detects the position of the touch when the electrodes on the two opposing substrates come into contact with each other by an external force, and is often built in, for example, a display device (for example, Patent Documents 1 and 2). 3). The capacitive type is, for example, built in a display device and detects the position of a touch when electrodes on two substrates facing each other due to an external force come close to each other.

JP 2001-75074 A JP 2007-52369 A JP 2007-95044 A

  This type of touch panel is required to have a cover made of glass or acrylic disposed on the surface for the purpose of preventing scratches on the surface and ensuring strength. In that case, it is conceivable to arrange the cover in close contact with the surface thereof. However, since this cover functions to disperse the external force applied by contact with a finger or the like, the pressure actually applied to the surface of the touch panel is reduced. This means that a stronger external force is required to recognize a touch than when there is no cover. In other words, the touch becomes heavy. Therefore, when inputting information using a stylus, for example, when touching over a wider area such as the belly of a finger, it is necessary to touch with a strong force, which makes it difficult to use.

  The present invention has been made in view of such problems, and an object thereof is to provide a touch panel, a display device with a touch detection function, an adapter for a touch panel, and an electronic device that can realize a light touch while having a surface cover. There is.

  The touch panel of the present invention includes a first substrate, a second substrate, and an elastic sheet. Here, the first substrate and the second substrate have electrodes formed on one surface, respectively, and are arranged apart from each other so that the electrode forming surfaces face each other. The elastic sheet originally functions as a cover member that covers the touch panel body, and is disposed on the side opposite to the electrode formation surface (operation surface side) of the second substrate and spaced from the second substrate. ing.

  The display device with a touch detection function of the present invention is a display device including the touch panel of the present invention. In this case, a display device using liquid crystal or an organic EL device can be used.

  The adapter for a touch panel of the present invention is used by being externally attached to an existing touch panel, and includes an elastic sheet and a stopper. Here, the elastic sheet is disposed away from the operation surface of the touch panel, and is fixed to the touch panel by a stopper.

  An electronic apparatus according to the present invention includes the touch panel according to the present invention. For example, an information terminal device such as a mobile phone, a PDA (Personal Data Assistance) and a mobile personal computer, a television receiver, a digital camera, and a digital movie. Applicable to video equipment.

  In the touch panel, the display device with a touch detection function, and the electronic device of the present invention, when a finger or the like touches (touches) the surface of the elastic sheet, the elastic sheet bends to the second substrate according to the local pressure. By touching and pressing this, the second substrate bends (dents), and the electrodes of the first substrate and the second substrate are locally approached or contacted to detect the touch. At this time, when the external force is transmitted to the second substrate via the elastic sheet, the force can be concentrated in a narrower contact area. For this reason, the pressure applied to the surface of the second substrate increases. As a result, it becomes possible to realize touch detection with a weaker external force than when there is no gap between the elastic sheet and the second substrate.

  The elastic sheet is preferably supported outside the touch detection area (touch operation area), and the support is preferably performed by a plurality of dot-like projections. The gap between the elastic sheet and the second substrate is preferably filled with air. In addition, a protrusion may be formed in the touch detection region on the surfaces of the elastic sheet and the second substrate facing each other.

  In the touch panel adapter of the present invention, when a finger or the like touches (touches) the surface of the elastic sheet, the elastic sheet bends (dents) and contacts the touch panel according to the local pressure. Detect touch.

  According to the touch panel, the display device with a touch detection function, the touch panel adapter, and the electronic device of the present invention, the gap is provided between the elastic sheet as the cover member disposed on the surface and the second substrate. While having a cover, detection with a lighter touch can be realized.

1A and 1B are a plan view and a cross-sectional view illustrating a configuration example of a display device with a touch detection function according to a first embodiment of the invention. FIG. 2 is a more detailed cross-sectional view of the display device with a touch detection function shown in FIG. 1. FIG. 3 is a schematic diagram illustrating an operation principle of the display device with a touch detection function illustrated in FIG. 2. FIG. 3 is a plot diagram illustrating an experimental example (contact area) of the display device with a touch detection function illustrated in FIG. 2. It is a table | surface showing the optical characteristic of the main member of the display apparatus with a touch detection function shown in FIG. FIG. 3 is a plot diagram and a table illustrating an example (operation characteristics) of the display device with a touch detection function illustrated in FIG. 2. FIG. 3 is a plot diagram and a table showing an example (another operation characteristic) of the display device with a touch detection function shown in FIG. 2. It is the top view and sectional drawing showing the modification in 1st Embodiment. It is sectional drawing showing the other modification in 1st Embodiment. It is sectional drawing showing the further another modification in 1st Embodiment. It is the top view and sectional drawing showing the example of 1 structure (display apparatus which attached the adapter for touchscreens externally) of the display apparatus with a touch detection function which concerns on the 2nd Embodiment of this invention. It is a perspective view showing the external appearance structure of the application example 1 among the display apparatuses with a touch detection function to which each said embodiment is applied. 12 is a perspective view illustrating an appearance configuration of an application example 2. FIG. 12 is a perspective view illustrating an appearance configuration of an application example 3. FIG. 14 is a perspective view illustrating an appearance configuration of an application example 4. FIG. FIG. 10 is a front view, a side view, a top view, and a bottom view illustrating an appearance configuration of an application example 5.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description will be given in the following order.
1. First embodiment (display device with touch detection function and touch panel)
2. Second embodiment (touch panel adapter)
3. Application examples

<1. First Embodiment>
[Configuration example]
(Overall configuration example)
FIG. 1 shows a configuration example of a display device with a touch detection function according to the first embodiment of the present invention, and FIG. 1 (A) shows a plan view of the display device 1 with a touch detection function, and FIG. Indicates a schematic cross-sectional structure in the direction of arrows I-I of the display device 1 with a touch detection function. The display device with a touch detection function 1 includes a display panel structure using a liquid crystal display element and a touch detection structure that detects bending caused by an external force. These display panel structure and touch detection structure are integrally formed. That is, this display device with a touch detection function is a so-called in-cell type device.

  The display device 1 with a touch detection function includes a liquid crystal display panel 10 including an array substrate 11 and a color filter substrate 12 facing each other, a backlight unit 14 that accommodates the liquid crystal display panel 10, and a front side of the liquid crystal display panel 10 (see FIG. , An elastic sheet 16 provided on the upper side). The backlight unit 14 is disposed inside the housing 18 via the buffer member 19.

  The array substrate 11 is a substrate in which a TFT (thin film transistor) for driving a liquid crystal element, a transparent pixel electrode, and the like (described later) are formed on a transparent substrate. The color filter substrate 12 is a substrate formed by forming a color filter, a transparent common electrode, and the like (described later) on a transparent substrate. A liquid crystal layer (not shown) is provided between the array substrate 11 and the color filter substrate 12. As will be described later, a touch sensor structure is formed on the surfaces of the array substrate 11 and the color filter substrate 12 facing each other.

  A COG (Chip On Glass) 13 is disposed on the array substrate 11. The COG 13 is a chip in which a circuit for driving a pixel electrode, a common electrode, a TFT, or the like is formed. In addition, the COG 13 may include a detection circuit for a touch sensor. The backlight unit 14 includes a backlight (not shown) disposed under the array substrate 11 and emits light toward the array substrate 11. When this light is modulated by the liquid crystal layer, an image is displayed and functions as a liquid crystal display device.

  The elastic sheet 16 is a transparent sheet member that is spaced apart from the color filter substrate 12 and is made of a material resistant to impact, such as glass, acrylic, or polycarbonate. A gap 15 is provided between the color filter substrate 12 and the elastic sheet 16 and is filled with air. A gap width D (see FIG. 2) of the gap 15 is secured by the outer frame portion 141 of the backlight unit 14. The outer frame portion 141 is erected from the bottom of the outer periphery of the backlight unit 14 toward the elastic sheet 16, and the upper end of the outer frame portion 141 contacts the elastic sheet 16 to maintain the gap width of the gap 15 at a predetermined value. It functions as a spacer.

  In addition, only the area | region corresponding to the effective display area S of the liquid crystal display panel 10 among the elastic sheets 16 may be made transparent, and other areas may be subjected to opaque processing. Further, the elastic sheet 16 may be composed of a multilayer material in order to improve strength or add functions, and may have, for example, a film layer for preventing reflection or preventing scratches on the surface.

  The buffer member 19 is located between the casing 18 and the backlight unit 14, the upper part of the backlight unit 14 is brought into close contact with the elastic sheet 16, and this portion functions as the spacer 141 described above. .

  Here, the array substrate 11 corresponds to a specific example of “first substrate” in the present invention, and the color filter substrate 12 corresponds to a specific example of “second substrate” in the present invention.

(Cross sectional structure of the main part of the display device 1 with a touch detection function)
FIG. 2A shows the cross-sectional structure of the main part of the display device 1 with a touch detection function in more detail. As shown in this figure, the array substrate 11 and the color filter substrate 12 are kept at a fixed distance by a spacer 25, and the liquid crystal layer 20 is sealed here.

  The array substrate 11 includes a TFT substrate 21, an adjustment layer 22, a plurality of pixel electrodes 23, and a polarizing plate 24. The adjustment layer 22 is a columnar layer that adjusts the height of the pixel electrode 23. The pixel electrodes 23 are arranged in a matrix on the surface of the TFT substrate 21 facing the liquid crystal layer 20. A part of each pixel electrode 23 is formed extending from the upper surface to the side surface so as to cover the adjustment layer 22. Although not shown, the array substrate 11 is provided with TFTs for driving the pixel electrodes 23, source lines for supplying image signals to the pixel electrodes 23, gate lines for driving the TFTs, and the like. ing.

  The color filter substrate 12 includes a counter substrate 26, a color filter 27, a common electrode 28, and a polarizing plate 29. A color filter 27 and a common electrode 28 are sequentially formed on the surface of the counter substrate 26 facing the liquid crystal layer 20. The color filter 27 is configured by periodically arranging, for example, three color filter layers of red (R), green (G), and blue (B). For each display pixel (pixel electrode 23), R, The three colors G and B are associated as one set. A phase difference plate (not shown) may be attached.

  In the array substrate 11 and the color filter substrate 12, polarizing plates 24 and 29 are disposed on each surface opposite to the side facing the liquid crystal layer 20, respectively. The polarizing plates 24 and 29 are configured to transmit or absorb a specific polarization component.

  The liquid crystal layer 20 includes a liquid crystal 30. The liquid crystal 30 modulates light passing therethrough according to the state of an electric field formed by a drive signal applied to the pixel electrode 23 and the common electrode 28. For example, TN (twisted nematic), VA (vertical) Liquid crystal of various modes such as orientation) and ECB (electric field control birefringence) are used.

  The spacer 25 has a columnar shape formed between the array substrate 11 and the color filter substrate 12, and functions as described above to keep the thickness of the liquid crystal layer 20, that is, the cell thickness constant. As the spacer 25, a material having a desired elastic deformation rate such as an acrylic material or a styrene material can be used. The spacer 25 itself is deformed together when the color filter substrate 12 is bent by an external force (contact force) applied to the surface of the elastic sheet 16. Note that the height of the spacer 25 when there is no external force is set to be higher than that of the adjustment layer 22, thereby preventing the pixel electrode 23 and the common electrode 28 from contacting each other.

  The elastic sheet 16 is spaced apart from the color filter substrate 12 via the gap 15 (with a gap width D). When an external contact object such as a finger comes into contact with the surface of the elastic sheet 16, the elastic sheet 16 is bent by the contact force to contact the upper surface of the color filter substrate 12, and the color filter substrate 12 is further bent. This bending is detected as a change in resistance or capacitance between the pixel electrode 23 formed on the array substrate 11 and the common electrode 28 formed on the color filter substrate 12. That is, the pixel electrode 23 and the common electrode 28 are used as electrodes for applying a drive signal of the liquid crystal display device, and are also used as electrodes for detecting a signal resulting from the touch of the touch sensor.

[Operation and Action]
Next, the operation and action of the display device with a touch detection function configured as described above will be described.
First, the overall operation of the display device with a touch detection function 1 according to the present embodiment will be described.

  The backlight unit 14 emits white light toward the array substrate 11. The polarizing plate 24 transmits only light in a specific polarization direction among the white light. The pixel electrode 23 and the common electrode 28 form an electric field between the electrodes based on the drive signal supplied from the COG 13. The liquid crystal 30 modulates the polarization direction of the light transmitted through the polarizing plate 24 according to the state of the electric field. The color filter 27 transmits light having wavelengths corresponding to R, G, and B, respectively. The polarizing plate 29 transmits only light of a specific polarization direction among the light. That is, the amount of light supplied from the backlight unit 14 is modulated by the liquid crystal 28 and the polarizing plates 24 and 29 and emitted as an image on the surface of the elastic sheet 16.

  FIG. 2B illustrates a cross-sectional structure of a main part of the display device with a touch detection function 1 in a state where there is an external contact object. The elastic sheet 16 is bent by an external force by an external contact object such as a finger, and the gap 15 is thereby narrowed and comes into contact with the color filter substrate 12. At this time, since the gap 15 exists, the contact area between the elastic sheet 16 and the color filter substrate 12 is smaller than the contact area between the external contact object and the elastic sheet 16 as described later. By this contact, the color filter substrate 12 is also bent, and the pixel electrode 23 of the color filter substrate 12 and the common electrode 28 of the array substrate 11 approach or come into contact with each other. This change in state causes a change in resistance or capacitance between the pixel electrode 23 and the common electrode 28. By detecting the presence / absence of this change and the position on the touch detection area using, for example, a detection circuit mounted on the COG 23, the presence and position of the external contact object can be detected.

  Next, portions related to the gap 15 and the elastic sheet 16 will be described in detail.

  The external force by the external contact object is transmitted to the elastic sheet 16 through the contact surface between the external contact object and the elastic sheet 16. The force is further transmitted to the touch sensor as pressure P through the contact surface between the elastic sheet 16 and the detection surface (color filter substrate 12) of the touch sensor.

The pressure P is expressed as follows.
P = F2 / A (1)
F = F1 + F2 + F3 (2)
Here, F is an external force due to an external contact object, and A is an effective area (external force transmission area) when the external force F is transmitted from the surface substrate 16 to the touch sensor surface (color filter substrate 12). The external force F has three components F1, F2, and F3. F1 is a force necessary for the elastic sheet 16 to bend and come into contact with the color filter substrate 12, F2 is a force applied to the touch sensor, and F3 is another force. For example, deformation other than the bending of the elastic sheet 16 And a dissipative force to the filling material in the gap 15 to be described later.

  In the present embodiment, touch recognition with a weak external force (F) is realized by providing the gap 15. As described later, this is based on the fact that the pressure P can be increased by reducing the external force transmission area A without increasing the force F2 in the equation (1). At this time, the gap 15 acts in a direction to reduce the external force transmission area A, as will be described later. Hereinafter, the functions of the gap 15 and the elastic sheet 16 will be described with reference to equations (1) and (2) and the drawings.

  First, the function of the gap 15 will be described. Here, in order to simplify the explanation, it is assumed that the external force F is directly transmitted to the touch sensor (F = F2).

  3A and 3B show the function of the gap 15. FIG. 3A shows a state without the gap 15 (comparative example), and FIG. 3B shows a state with the gap 15 (this embodiment).

  When there is no gap 15 and the elastic sheet 16 and the color filter substrate 12 are in close contact, the external force F is dispersed by the elastic sheet as shown in FIG. An area (external force transmission area) A in which an external force is transmitted to the substrate 12 is larger than a contact area B between the external contact object and the elastic sheet 16. Thereby, for example, the pressure P on the detection surface of the touch sensor is reduced compared to the case where the elastic sheet 16 is not provided and the external contact object is in direct contact with the color filter substrate 12, so that the external force is stronger because the touch is recognized. Is required.

  On the other hand, when the gap 15 is provided, as shown in FIG. 3B, the external force transmission area A is smaller than the external force transmission area A when there is no gap 15 (see FIG. 3A). That is, when the external force is transmitted from the surface substrate 16 to the color filter substrate 12, the pressure P applied to the surface of the touch sensor (color filter substrate 12) increases because it concentrates in a narrower contact area. Therefore, it is possible to realize touch recognition with a weak external force F compared to when there is no gap 15. Thus, in order to realize a light touch, for example, if the size is about the size of a liquid crystal display device of a mobile phone, the gap width D may be about 10 μm to 110 μm, and particularly preferably about 50 μm to 90 μm. .

  4A and 4B show an experimental example of the touch contact area in the display device 1 with a touch detection function, where FIG. 4A shows a state without the gap 15 (comparative example), and FIG. 4B shows the gap 15 (gap width). 50 um) is shown (this embodiment). In this experiment, a 10 mm diameter planar indenter made of human skin (registered trademark) gel (Asker C hardness 5) was used as an external contact object, and when there was no gap 15 and when touched with the same force. The map of the reaction point in the detection area | region of a touch sensor is shown. As shown in FIG. 4B, it can be confirmed that the external force is concentrated by providing the gap 15. As a result, as described above, a light touch is realized.

  Furthermore, the concentration of the external force improves the touch position recognition accuracy and linearity of the touch sensor. The touch position is recognized by, for example, calculating the barycentric coordinates using the map data of the reaction points in the surface of the touch sensor as shown in FIG. In particular, in the case of a touch sensor built in a liquid crystal display device as in the present embodiment, manufacturing variations in the distance between the pixel electrode 23 and the common electrode 28 (height of the adjustment layer 22), the spacer 25, and the pixel electrode 23 and the common electrode 28 may cause variations in the sensitivity of each sensor element. In this case, when the user touches a wide area such as a finger, as shown in FIG. 4A, the density of reaction points due to variations in element sensitivity occurs. Therefore, even if the barycentric coordinates are calculated, there is a possibility that sufficient touch position recognition accuracy and linearity cannot be ensured. On the other hand, when the gap 15 is provided, as shown in FIG. 4B, the reaction points of the touch sensor are concentrated in a narrow range, so that the touch position recognition accuracy and linearity are improved.

  Next, the function of the elastic sheet 16 will be described.

  It is desirable that the external force F given by the contact of the external contact object is almost directly transmitted to the touch sensor (F = F2). As is clear from Expression (2), F1 and F3 prevent the external force F from being transmitted to the touch sensor. Therefore, it is desirable to make F1 and F3 sufficiently smaller than the external force F. If F1 and F3 are not negligible compared to the external force F, only a part of the external force F is transmitted to the touch sensor. However, as shown in the equation (1), even in that case, from the elastic sheet 16 Since the area (external force transmission area) A in which force is transmitted to the color filter substrate 12 can be reduced, it is possible to prevent the pressure P from being lowered and to recognize touch with a weak external force.

In order to make F1 small, that is, to make the elastic sheet 16 bend easily, the material and thickness of the elastic sheet 16 may be adjusted. The bending of the elastic sheet 16 can be expressed as the following equation.
δ = αWa ⁴ / (Et ³ ) (3)
Here, δ is a deflection amount, W is a load, a is a distance between two opposing sides that support the elastic sheet 16, E is a Young's modulus, and t is a plate thickness of the elastic sheet 16. . Α is a coefficient that depends on the support method of the elastic sheet 16, and has a different value depending on, for example, the case where the elastic sheet 16 is supported on four sides (FIG. 1B) or the case where the elastic sheet 16 is supported on four points. .

  Since F1 is a force necessary for the elastic sheet 16 to bend by the gap width D of the gap 15 and contact the color filter substrate 12, the amount of deflection δ of the elastic sheet 16 is equal to the gap 15 in Equation (3). This corresponds to the load W when the gap width D becomes equal.

In order to reduce F1, for example, a material having a small Young's modulus E may be used as the material of the elastic sheet 16, the thickness t of the elastic sheet 16 may be reduced, or the gap width D may be reduced. On the other hand, reducing the Young's modulus E and the thickness t of the elastic sheet 16 means that it is easy to bend, and it is difficult to ensure the strength that is the original purpose of the elastic sheet. Therefore, it is necessary to consider both F1 and strength. Here, β is defined as a parameter of the elastic sheet 16.
β = 1 / (Et ³ ) (4)
This equation is obtained by extracting the terms of Young's modulus E and the thickness t of the elastic sheet 16 from the equation (3). In order to reduce F1, β increases, but in order to ensure strength, β should be small. In particular, in a portable information terminal such as a mobile phone, the β value is preferably about 4 or less, and preferably about 1 to 4.

  As another method of reducing F1, the distance a between two opposing sides that support the elastic sheet 16 may be increased. In FIG. 1, the elastic sheet 16 is supported by the outer frame portion 141 of the backlight unit 14, but may be supported by other portions. For example, the elastic sheet 16 may be supported by a part further away from the effective display area S, such as a housing or an outermost cover of an electronic device to which the display device with a touch detection function 1 is applied. 16 may be integrated with the housing. This makes it possible to realize touch recognition with a weak external force F, particularly in a region close to a portion where the display substrate 16 is supported, such as an edge of the effective display region S.

  In order to reduce F3, for example, a substance having a low viscosity and a high fluidity may be used as the material filling the gap 15. For example, an inert gas such as nitrogen gas or a gas such as air is preferable. . In particular, air is desirable in view of ease of manufacture and cost. However, as described later, when importance is attached to the optical characteristics of the display panel, a liquid or gel-like substance may be used.

  For example, when the touch sensor is built in the liquid crystal display device as in the present embodiment, the influence of the elastic sheet 16 and the gap 15 on the optical characteristics (display characteristics) of the display panel is also important. This is because the visibility depends on the difference in refractive index between the color filter substrate 12, the gap 15 and the elastic sheet 16 and the light transmittance of the gap 15 and the elastic sheet 16.

  As a material of the elastic sheet 16, for example, glass, acrylic, polycarbonate, or the like can be used. The refractive index is 1.51 for glass, 1.49 for acrylic, and 1.59 for polycarbonate. Other materials may be used as long as the refractive index is 1.8 or less. As a material for filling the gap 15, a material close to the refractive index of the elastic sheet 16 is preferable, and a material having a refractive index of 1 to 1.7 is desirable. For example, air (refractive index 1.0), ethanol (1.36) and glycerin (1.47) can be used.

  On the other hand, the light transmittance of the elastic sheet 16 is 92% (thickness: 0.2 mm) for glass, 92% (0.5 mm) for acrylic, and 90% (0.5 mm) for polycarbonate. .

  FIG. 5 is an experimental example showing the light transmittance when the elastic sheet 16, the gap 15, and the color filter substrate 12 are combined. A transmittance of 90% or more can be realized at a gap width of 100 μm. When the gap 15 is filled with a material (for example, a liquid or a gel material) having a refractive index close to that of the elastic sheet 16 or the color filter substrate 12, light transmittance can be improved. The combination is not limited to these, and a combination that is equal to or higher than the transmittance of 85% in the conventional resistive film type touch panel is desirable.

  As described above, the display device with a touch detection function of the present embodiment has a very simple configuration in which the gap 15 is provided between the touch panel body and the elastic sheet 16, and necessary members are also included. Few. In addition, since there is no fine structure in the manufacturing process, there is no need for additional lithography and printing processes, and precise alignment is not necessary. Therefore, it is excellent in terms of cost, productivity, and quality. Further, for example, when the elastic sheet 16 is integrated with the housing as described above, the design of the electronic device is further improved.

[Example]
Based on the present embodiment, a display device with a touch detection function was prototyped. The touch panel type of the display device with a touch detection function is an electrode contact type, and the size of the touch detection area is 37.44 mm × 49.92 mm. The elastic sheet is supported by four sides as in the case shown in FIG. 1, and the distances a between the two opposing sides are 55.10 mm and 42.56 mm, respectively. The gap width is in the range of 105 μm or less, and the gap is filled with air.

  FIGS. 6A and 6B show the relationship between β and the operation start pressure when the material and thickness of the elastic sheet are changed. Here, the operation start pressure is a minimum external force necessary for the touch sensor to detect a touch when an external force is applied to the elastic sheet. The external force was applied to the center of the detection region of the touch sensor using a flat indenter having a diameter of 10 mm made of human skin (registered trademark) gel (Asker C hardness 5). A scale was placed under the display device 1 with a touch detection function, and an operation start pressure was obtained based on the value of the scale when an external force was applied and the touch sensor detected a touch.

  As shown in FIG. 6A, the operation start pressure decreases as β increases. As described above, in order to lighten the touch (lower the operation start pressure), F1 needs to be reduced, but at this time, β increases. The operation starting pressure when there is no elastic sheet is 67 gf (reference line).

  The operation start pressure is desirably lower than that when no cover is provided. Therefore, it is desirable to design the material and thickness of the cover material so that β is 1 to 4.

  7A and 7B show the relationship between the gap width of the gap 15 and the operation start pressure. Here, 0.2 mm thick glass (Asahi Glass low expansion glass, AN100) was used as the elastic sheet.

  As shown in FIG. 7A, when there is no gap and the elastic sheet and the color filter are in close contact (gap width: 0 μm), the operation start pressure is a high value of 114 gf, and the gap width is As it spreads, the operation start pressure decreases to about 40 gf. This is because, as shown in FIG. 3, the external force transmission area A is narrowed by increasing the gap width, and the pressure P on the touch sensor surface (color filter substrate 12) is increased. On the other hand, when the gap width is further expanded, the operation start pressure slightly increases. This is because, as described above, when the gap width is further increased, the elastic sheet needs to be greatly bent in order to recognize the touch, and F1 in Expression (2) increases. That is, the external force F given by the contact of the external contact object is not easily transmitted to the touch sensor.

  As described above, in order to reduce the operation start pressure and realize a light touch, the gap width may be about 10 μm to 110 μm. Thereby, the operation start pressure can be made lower than the operation start pressure (67 gf) when there is no elastic sheet.

  As described above, in the present embodiment, since the elastic sheet is provided on the surface, it is possible to prevent the surface from being scratched and ensure the strength. In addition, since a gap is provided between the elastic sheet and the color filter substrate, when an external force is transmitted to the color filter substrate 12 via the elastic sheet 16, the force can be concentrated in a narrower contact area. it can. For this reason, the pressure P applied to the surface of the touch sensor (color filter substrate 12) increases, and touch detection with a weak external force F can be realized compared to when there is no gap 15.

[Modification of First Embodiment]
(Modification 1-1)
In the above embodiment, as shown in FIG. 1, the elastic sheet 16 is supported by the upper four sides of the outer frame portion 141 of the backlight unit 14, but is not limited thereto. For example, the support may be performed by a plurality of points, or may be performed at other portions outside the effective display area S. FIG. 8A shows a plan view of the display device 1B with a touch detection function, and FIG. 8B shows a schematic cross-sectional structure of the display device 1B with a touch detection function in the direction of arrows VIII-VIII. The elastic sheet 16 is supported by eight spacers 17 formed on the color filter so as to surround the effective display area S. For example, a double-sided tape can be used as the spacer 17.

(Modification 1-2)
In the above embodiment, a plurality of protrusions may be formed on the surfaces of the color filter substrate 12 and the elastic sheet 16 that face each other. 9A and 9B show a cross-sectional structure of a main part of the display device with a touch detection function 1C. FIG. 9A shows a case where protrusions are formed on the color filter substrate 12, and FIG. The case where it formed is shown, (C) shows the case where protrusion is alternately formed on both the color filter substrate 12 and the elastic sheet 16. In this example, the protrusion 90 has a hemispherical shape and is formed so as to correspond to each touch sensor element. Thereby, an external force is applied to the surface of the elastic sheet 16 due to the contact of the external contact object, and when the elastic sheet 16 is bent, the elastic sheet 16 and the color filter substrate 12 come into contact with each other through the protrusion 90. That is, since the contact area is small, the pressure applied to the touch sensor element increases, and a touch can be detected with a weaker external force. Note that the formation of the protrusions is not limited to that shown in FIG. 9, but may be other protrusion patterns or protrusion shapes that concentrate external force. For example, in FIG. 9C, one protrusion is alternately formed on both the color filter substrate 12 and the elastic sheet 16, but two protrusions may be alternately formed. Further, the protrusion shape may be a columnar shape.

(Modification 1-3)
In the above embodiment, the liquid crystal display device is used as the display device, but the present invention is not limited to this. For example, an organic EL display device may be used as the display device. FIG. 10 illustrates a cross-sectional structure of a main part of a display device with a touch detection function 1C using an organic EL display device. The display device with a touch detection function 1 </ b> C includes an array substrate 11 </ b> B, a sensor substrate 12 </ b> B, an organic EL layer 39, a spacer 25, a gap 15, and an elastic sheet 16. Here, the array substrate 11B corresponds to a specific example of “first substrate” in the present invention, and the sensor substrate 12B corresponds to a specific example of “second substrate” in the present invention.

  The array substrate 11B includes a TFT substrate 21, an adjustment layer 22, a sensor pixel electrode 31, and a pixel electrode 32. The adjustment layer 22 is a columnar layer that adjusts the height of the sensor pixel electrode 31. A plurality of sensor pixel electrodes 31 and pixel electrodes 32 are formed on the surface of the TFT substrate 21 facing the organic EL layer 39 so as to be arranged in a matrix. The portion extends to the upper surface so as to cover the adjustment layer 22. The sensor substrate 12 </ b> B has a counter substrate 26 and a sensor electrode 33. As a material to be filled between the array substrate 11B and the sensor substrate 12B, a material having as low a viscosity as possible and having high fluidity may be used, and a material that does not deteriorate an organic EL layer described later is desirable. For example, an inert gas such as nitrogen gas or a gas such as air is preferable. In particular, air is desirable in view of ease of manufacture and cost. However, when importance is attached to the optical characteristics of the display panel, for example, a liquid such as ethanol or glycerin or a highly fluid resin may be used in order to reduce interface reflection and the like. The organic EL layer 39 is a layer composed of a plurality of organic EL elements 40. The organic EL element 40 has a hole transport layer, a light emitting layer, and an electron transport layer formed between the sensor pixel electrode 31 and the pixel electrode 32, and the light emitting layer is formed based on a drive signal applied to these electrodes. For example, light of three colors of red, blue, and green is emitted using the state transition of the light emitting material (from the excited state to the ground state). When an external contact object is present on the elastic sheet 16, the display substrate 16 bends due to the external force of the contact as in the above embodiment, thereby narrowing the gap 15 and bringing the elastic sheet 16 and the sensor substrate 12B into contact. This change in state is detected as a change in resistance or capacitance between the sensor pixel electrode 31 and the sensor electrode 33, and a touch is detected.

(Modification 1-4)
In the above embodiment, the touch sensor is built in the liquid crystal display device, but may not be built in. In this case, for example, by externally installing a touch panel having a touch sensor on the display surface of a display device such as a liquid crystal display device, the same operations and effects as in the present embodiment can be realized.

<2. Second Embodiment>
Next, a touch panel adapter according to a second embodiment of the present invention will be described. Note that substantially the same components as those of the display device with a touch detection function according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[Configuration example]
(Overall configuration example)
FIG. 11 shows a configuration example of a display device with a touch detection function to which the touch panel adapter according to the second embodiment of the present invention is attached. FIG. 11A is a plan view thereof, and FIG. 11 shows a schematic cross-sectional structure in the direction of arrows XI-XI in FIG. This display device 3 with a touch detection function is configured such that a touch panel adapter 2 is externally installed on the surface of an in-cell type liquid crystal display device in which a touch sensor for detecting a bend caused by an external force is incorporated.

  The display device 3 with a touch detection function includes a stopper 51 in an outer region of the display surface. The stopper 51 is a member for externally fixing the elastic sheet 16 to the housing 18, so that the elastic sheet 16 is disposed apart from the color filter substrate 12. Other configurations are the same as those of the first embodiment (FIGS. 1 and 2).

[Operation and Action]
The operation and action of the display device with a touch detection function 3 using the touch panel adapter 2 of the present embodiment are exactly the same as those described in the first embodiment. That is, when an external contact object comes into contact with the surface of the elastic sheet 16, the elastic sheet 16 bends due to the external force of the contact, thereby narrowing the gap 15 and contacting the color filter substrate 12. In this case, the gap 15 functions so that the contact area between the elastic sheet 16 and the color filter substrate 12 (the surface of the touch sensor) is smaller than the contact area between the external contact object and the elastic sheet 16. As a result, the pressure P on the surface of the touch sensor increases, so that touch detection is possible even with a weak external force.

  The touch panel adapter 2 of the present embodiment can be externally attached to the surface of an existing touch panel or a display device with a touch detection function, thereby enabling touch detection with a weak external force. As the applicable touch panel and display device with a touch detection function, any touch sensor that detects an external force by touch may be used.

  As described above, in the present embodiment, since it can be externally attached to the surface of an existing touch panel or a display device with a touch detection function, it is possible to prevent scratches on the surface and to ensure the strength of those devices. The operability of the device can be improved so that touch detection is possible even with a weaker external force. Other effects are the same as in the case of the first embodiment.

<3. Application example>
Next, with reference to FIGS. 12 to 16, application examples of the display device with a touch detection function described in the above embodiment and the modified examples will be described. The display device with a touch detection function according to the above-described embodiments can be applied to electronic devices in various fields such as a television device, a digital camera, a notebook personal computer, a mobile terminal device such as a mobile phone, or a video camera. is there. In other words, the display device with a touch detection function according to the above-described embodiment can be applied to electronic devices in various fields that display an externally input video signal or an internally generated video signal as an image or video. It is.

(Application example 1)
FIG. 12 illustrates an appearance of a television device to which the display device with a touch detection function according to the above-described embodiment or the like is applied. The television apparatus has, for example, a video display screen unit 510 including a front panel 511 and a filter glass 512. The video display screen unit 510 is obtained by the display device with a touch detection function according to the above-described embodiment and the like. It is configured.

(Application example 2)
FIG. 13 illustrates an appearance of a digital camera to which the display device with a touch detection function according to the above-described embodiment or the like is applied. The digital camera includes, for example, a flash light emitting unit 521, a display unit 522, a menu switch 523, and a shutter button 524, and the display unit 522 is a display device with a touch detection function according to the above-described embodiment and the like. It is comprised by.

(Application example 3)
FIG. 14 illustrates an appearance of a notebook personal computer to which the display device with a touch detection function according to the above-described embodiment or the like is applied. The notebook personal computer includes, for example, a main body 531, a keyboard 532 for inputting characters and the like, and a display unit 533 for displaying an image. The display unit 533 is a touch according to the above-described embodiment and the like. It is comprised by the display apparatus with a detection function.

(Application example 4)
FIG. 15 illustrates an appearance of a video camera to which the display device with a touch detection function according to the above-described embodiment or the like is applied. This video camera has, for example, a main body 541, a subject shooting lens 542 provided on the front side surface of the main body 541, a start / stop switch 543 at the time of shooting, and a display 544. The display unit 544 includes a display device with a touch detection function according to the above-described embodiment and the like.

(Application example 5)
FIG. 16 illustrates an appearance of a mobile phone to which the display device with a touch detection function according to the above-described embodiment or the like is applied. For example, this mobile phone is obtained by connecting an upper housing 710 and a lower housing 720 with a connecting portion (hinge portion) 730, and includes a display 740, a sub-display 750, a picture light 760, and a camera 770. Yes. The display 740 or the sub-display 750 is configured by a display device with a touch detection function according to the above-described embodiment or the like.

DESCRIPTION OF SYMBOLS 1, 1B, 1C, 1D, 3 ... Display device with a touch detection function, 2 ... Adapter for touch panel, 10 ... Liquid crystal display panel, 11, 11B ... Array substrate, 12 ... Color filter substrate, 12B ... Sensor substrate, 13 ... COG , 14 ... Backlight unit, 15 ... Gap, 16 ... Elastic sheet, 18 ... Housing, 19 ... Buffer member, 20 ... Liquid crystal layer, 21 ... TFT substrate, 22 ... Adjustment layer, 23 ... Pixel electrode, 24, 29 ... Polarizing plate, 17, 25 ... spacer, 26 ... counter substrate, 27 ... color filter, 28 ... common electrode, 30 ... liquid crystal, sensor pixel electrode 31, pixel electrode ... 32, sensor electrode 33, 39 ... organic EL layer, 40 ... Organic EL element 51 ... Stopper, 90 ... Protrusion, 141 ... Outer frame part, A ... External force transmission area, B ... Contact area, D ... Gap width, E ... Young's modulus, S ... Effective display area, t ... Elastic sheet The thickness of.

Claims (10)

An electrode is formed on each of the surfaces, and a first substrate and a second substrate that are spaced apart from each other so that the electrode forming surfaces face each other;
A touch panel comprising: an elastic sheet disposed on the opposite side of the second substrate from the electrode formation surface and spaced from the second substrate. The touch panel according to claim 1, wherein air is filled between the second substrate and the elastic sheet. The touch panel according to claim 1, wherein the elastic sheet is supported outside the touch detection area. The touch panel according to claim 1, wherein the elastic sheet is supported by a plurality of dot-like projections. The touch panel as set forth in claim 1, wherein a protrusion is formed in a touch detection region on a surface of the second substrate and the elastic sheet facing each other. An electrode is formed on each of the surfaces, and a first substrate and a second substrate that are spaced apart from each other so that the electrode forming surfaces face each other;
A display layer disposed between the first substrate and the second substrate;
A display device with a touch detection function, comprising: an elastic sheet disposed on the opposite side of the second substrate from the electrode formation surface and spaced from the second substrate. The display device with a touch detection function according to claim 6, wherein the display layer is a liquid crystal layer. The display device with a touch detection function according to claim 6, wherein the display layer is an organic EL layer. An elastic sheet disposed away from the detection area surface of the touch panel;
A touch panel adapter comprising: a stopper for fixing the plate-like cover member to the touch panel. An electrode is formed on each of the surfaces, and a first substrate and a second substrate that are spaced apart from each other so that the electrode forming surfaces face each other;
An electronic device comprising: a touch panel having an elastic sheet disposed on a side opposite to the electrode formation surface of the second substrate and spaced from the second substrate.

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