JP2009110248A - Touch panel, display device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch panel, a display device, and electronic equipment whose configurations are simple, and touch panel position detecting precision is high. <P>SOLUTION: This touch panel is provided with a touch panel substrate 42 having an input face 42A and a piezoelectric element 43 arranged on either an input face 42A or a back face 42B of the touch panel substrate 42, wherein the piezoelectric element 43 is arranged at least one by one at a portion of each side of the touch panel substrate 42, and a groove part 57 is formed at a position overlapped with at least the piezoelectric element 43 when it is flatly viewed on the face of the touch panel substrate 42 at the opposite side of the piezoelectric element 43. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a touch panel, a display device, and an electronic device.

  In recent years, with the spread of small information electronic devices such as personal digital assistants (PDAs) and personal computers, a display with a so-called touch panel function that performs an input operation by bringing an object such as a finger or a pen into contact with the display screen is added. The device is widely used.

Here, as a method for detecting the contact position of an object such as a finger or a pen, for example, a method using a resistance film or a piezoelectric element is known. In the resistive film method, a change in the resistance value of the resistive film caused by contact of the object with the resistive film is detected, and the contact position of the object is detected (for example, Patent Document 1). In the piezoelectric element method, the pressing position is detected based on a change in an output signal caused by an external force applied in the thickness direction of the piezoelectric element (for example, Patent Documents 2 and 3).
JP-A 61-000825 Japanese Patent Application Laid-Open No. 11-212725 JP-A-06-139018

  Each of the above methods has advantages and disadvantages, and uses and usage conditions are limited. For example, the resistance film method is not durable because the resistance film on the medium surface may be damaged during use. Furthermore, in the piezoelectric element method, since the piezoelectric element is used in the thickness mode, the position detection accuracy is extremely lowered when the medium is a hard material or a thick shape or when the pressing force is small. There's a problem. That is, if the pressing force is not large, the piezoelectric element is not deformed, so that there is a force in the input. In addition, since the position detection sensitivity is low, it takes time when the user inputs information. Further, in Patent Documents 2 and 3 described above, it is very difficult to accurately detect the pressed position when the area of the medium is large.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a touch panel, a display device, and an electronic apparatus with a simple configuration and high position detection accuracy.

  In order to solve the above problems, a touch panel according to the present invention includes a touch panel substrate having an input surface and a piezoelectric element disposed on either the input surface or the back surface of the touch panel substrate. At least one groove is disposed on a part of each side, and a groove is formed on the surface of the touch panel substrate opposite to the piezoelectric element at a position overlapping with at least the piezoelectric element in plan view.

According to the present invention, when the input surface of the touch panel substrate is pressed by the user, the portion where the groove is formed is locally bent, and the piezoelectric element is easily deformed. When the touch panel substrate is easily bent and deformed, the piezoelectric element is also bent and deformed simultaneously following the deformation of the touch panel substrate, and an electromotive force corresponding to the amount of deformation is generated. The position pressed by the user can be detected by the difference in electromotive force from each piezoelectric element arranged on each side of the touch panel substrate. In the present invention, since the piezoelectric element is used in the bending mode, the pressing position can be detected with higher accuracy than the method of detecting the pressing force in the thickness direction (thickness mode). In addition, the output signal from the piezoelectric element is increased by forming a groove on the touch panel substrate to facilitate bending, and the position detection accuracy is further improved.
In the present invention, since the electromotive force generated by the piezoelectric element is used, the pressed position can be accurately detected even if the current consumption is small and the pen is used other than the user's finger. it can.
Therefore, a highly sensitive touch panel with high position detection accuracy can be obtained with a simple configuration.

Moreover, it is preferable that a groove part is a frame shape which follows the edge of a touchscreen board | substrate.
According to such a configuration, the amount of deformation (curvature) of the touch panel substrate is improved, and the entire touch panel substrate is deformed in accordance with the pressing force of the user, so that the detection accuracy of the pressed position is improved.

Moreover, it is preferable that a plurality of piezoelectric elements are arranged on each side of the touch panel substrate.
According to such a configuration, the detection accuracy of the pressed position is improved.

Moreover, it is preferable that the depth of a groove part exists in the range of 20 to 70% with respect to the thickness of a touch panel substrate.
For example, when the depth of the groove is less than 20% of the thickness of the touch panel substrate, the touch panel substrate is hardly deformed, and the electromotive voltage output from each piezoelectric element is small. Therefore, there is a possibility that the pressed position cannot be accurately detected. In addition, when the depth of the groove exceeds 70% of the thickness of the touch panel substrate, the electromotive voltage from the piezoelectric element increases, but the thickness of the groove portion becomes thin, so the touch panel substrate may be damaged during use. Durability is poor. In addition, the entire position of the substrate is pushed in without being pressed and the position detection accuracy may be lowered.
Therefore, by making the depth of the groove part within 20 to 70% of the thickness of the touch panel substrate, the touch panel substrate is more easily deformed than before, and the accuracy of detecting the pressed position is improved and the durability is also secured. It becomes.

The piezoelectric element has a first electrode, a piezoelectric film and a second electrode laminated on the touch panel substrate, and the piezoelectric film is made of ZnO, AlN, PZT, LiNbO ₃ , LiTaO ₃ , KNbO _3. It is preferable that at least one of them is included.
According to such a configuration, it is possible to obtain a piezoelectric film that can stably obtain a piezoelectric effect that develops an electromotive force in proportion to a bending stress (deformation amount).

Moreover, it is preferable that a protective film is provided on the piezoelectric element, and the protective film is made of SiO ₂ or Al ₂ O ₃ .
According to such a configuration, deterioration of the piezoelectric element can be prevented for a long time.

Moreover, it is preferable to have a convex portion that is disposed on the same plane in the vicinity of the piezoelectric element and has a height higher than that of the piezoelectric element on the wiring connected to the piezoelectric element.
According to such a configuration, a convex portion is interposed between the touch panel and the other member so that a space is formed between the piezoelectric element and the other member, and the piezoelectric element is moved to the other member by deformation of the touch panel substrate. Can be prevented from touching. Thereby, malfunction of a piezoelectric element can be prevented. In addition, the frame region of the touch panel substrate can be reduced by forming the convex portion on the wiring connected to the piezoelectric element, and as a result, the touch panel substrate can be reduced in size.

Moreover, it is preferable that the notch part fitted with the structural member of the apparatus with which the said touch panel is mounted | worn is formed in the touchscreen board | substrate outside the groove part of the input surface.
According to such a configuration, positioning to the panel case and the like are facilitated. In addition, it is easy to make the top surface of the panel case and the input surface of the touch panel substrate flush with each other so that there is no step on the input surface. In addition, since the touch panel can be positioned with respect to the above-described device simply by fitting the component of the device to which the touch panel is mounted into the notch, it is possible to easily and accurately align each other.

The touch panel of the present invention includes a touch panel substrate having an input surface and a piezoelectric element disposed on either the input surface or the back surface of the touch panel substrate, and at least one piezoelectric element is disposed on each side of the touch panel substrate. In the touch panel substrate, a cavity is formed at a position overlapping the piezoelectric element in plan view.
According to such a configuration, when the input surface of the touch panel substrate is pressed by the user, the touch panel substrate is easily deformed with the hollow portion provided in the substrate as a base point. Then, following the deformation of the touch panel substrate, the piezoelectric element is also deformed at the same time, and an electromotive force corresponding to the deformation amount is generated. The position pressed by the user can be detected with high accuracy by the difference in electromotive force between the piezoelectric elements arranged on each side of the touch panel substrate. In the present invention, since the electromotive force generated by the piezoelectric element is used, the pressed position can be detected with high accuracy even when the current consumption is reduced and a pen having no conductivity other than the user's finger is used. . Therefore, a touch panel with high position detection accuracy can be obtained with a simple configuration.

A display device of the present invention is a display device having the above touch panel and a display panel, and the display panel includes a pair of substrates and an electro-optical material sandwiched between the pair of substrates. And
According to the present invention, since the touch panel with high detection accuracy of the pressed position by the user is provided, it is possible to accurately detect the user information along the image displayed on the display panel, that is, the user's operation input.

Moreover, it is preferable that the touch panel and the display panel are disposed to face each other via a convex portion formed on the touch panel.
According to such a configuration, the piezoelectric element can be prevented from coming into contact with the display panel due to the deformation of the touch panel substrate, and the pressed position can be detected with high accuracy.

Moreover, it is preferable that the touch panel and the display panel are joined by an optical elastic adhesive film.
According to such a configuration, the touch panel and the display panel can be favorably bonded without hindering the deformation of the touch panel substrate or impairing the visibility of the image displayed on the display panel. In addition, since the adhesive has elasticity, the impact resistance is high.

An electronic apparatus according to the present invention includes the display device described above.
According to the present invention, since the display device having the touch panel with high detection accuracy of the pressed position is provided, an electronic device with good responsiveness can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

(First embodiment)
FIG. 1A is a cross-sectional view showing an overall configuration of a liquid crystal display device which is an example of a display device according to the present invention, where FIG. 1B is an enlarged view of a main part of the touch panel, and FIG. It is a top view which shows the input surface side, Comprising: (b) is a top view which shows the back surface side of a touchscreen board | substrate. FIG. 3 is a diagram showing an internal configuration of the touch panel.
In the following description, the surface on the liquid crystal layer side of the element substrate and the color filter substrate is referred to as an inner surface, and the surface opposite to the liquid crystal layer is referred to as an outer surface.

A liquid crystal display device (display device) 100 according to the present embodiment is roughly composed of a touch panel 40 and a liquid crystal display panel 30.
The touch panel 40 includes a touch panel substrate 42 having an input surface 42A and a position detection sensor that detects a pressing position of the input surface 42A by the user. The liquid crystal display panel 30 includes the element substrate 1 and the color filter substrate 2. And a liquid crystal layer 4 sandwiched therebetween. The touch panel 40 has the back surface 42B opposite to the input surface 42A of the touch panel substrate 42 facing the outer surface 2A of the color filter substrate 2 of the liquid crystal display panel 30 with the liquid crystal display panel 30 by the optical elastic adhesive film 58. It is joined.

[Touch panel]
First, the configuration of the touch panel will be described.
As illustrated in FIG. 1, the touch panel 40 includes a touch panel substrate 42 and a position detection sensor, and is disposed outside the liquid crystal display panel 30.
The touch panel substrate 42 has a predetermined thickness made of glass or highly transparent polycarbonate, polyethylene, acrylic, or the like, and an image displayed in the display area of the liquid crystal display device 100 is passed through the touch panel substrate 42. Can be provided to users. The touch panel substrate 42 is disposed with the back surface 42B side facing the color filter substrate 2 of the liquid crystal display panel 30, and has an input surface 42A on which the user actually performs input with a finger or the like on the surface opposite to the back surface 42B. is doing. That is, the outer surface side of the touch panel substrate 42 is a side on which the user inputs information while visually recognizing an image.

  As shown in FIG. 2A, the input surface 42A includes an input area X (an area corresponding to the display area of the liquid crystal display panel 30) and a wiring area Y (the non-display of the liquid crystal display panel 30) surrounding the input area X. Area corresponding to the area). A plurality of piezoelectric elements 43 are provided on each side 42 a, 42 b, 42 c, 42 d of the touch panel substrate 42 at the periphery of the touch panel substrate 42 in the wiring region Y. In the present embodiment, two piezoelectric elements 43 are arranged around each of the sides 42a to 42c around the input region X at a predetermined interval.

 As shown in FIG. 1B, the piezoelectric element 43 has a configuration in which a piezoelectric film 45 is sandwiched between an upper electrode 44a and a lower electrode 44b. The piezoelectric film 45 is, for example, a film produced by stretching and subjected to a poling process so as to generate a piezoelectric action. By arranging the electrodes 44a and 44b on both sides of the piezoelectric film 45, an electromotive force generated when the piezoelectric film 45 is deformed can be taken out.

  The lower electrode 44b is configured by sequentially stacking a Pt layer and an Ir layer, and has a thickness of about 100 to 1000 nm.

Further, the upper electrode 44a can employ a conductive material, such as platinum (Pt), iridium (Ir), aluminum (Al), etc. In this embodiment, iridium is used to make the thickness of about 100 to 1000 nm. It is formed in a film thickness.
In addition, the combination of the electrodes 44a and 44b is appropriately selected from Al, Au / Cr, Ni, Mo, Pt / Ti, and various combinations are conceivable.

The piezoelectric film 45 can employ ZnO (zinc oxide), AlN (aluminum nitride), PZT (lead zirconate titanate), LiNbO ₃ (lithium niobate), LiTaO ₃ (lithium tantalate), or the like. For example, when the touch panel substrate 42 is made of glass, one having a predetermined thickness made of ZnO, AlN, PZT, or the like is used. The piezoelectric film 45 generates an electromotive force according to bending deformation as described above. The piezoelectric film 45 is formed to have a predetermined thickness from the viewpoint of performance such as the magnitude of output.

  Such a piezoelectric element 43 is attached to the touch panel substrate 42 using an adhesive or the like, and deforms according to the deformation of the touch panel substrate 42. Here, the piezoelectric elements 43 are bonded so as not to be peeled off from the touch panel substrate 42 due to deformation.

  And among the plurality of piezoelectric elements 43, the upper electrodes 44a of the four piezoelectric elements 43 arranged along the adjacent sides 42a and 42b of the touch panel substrate 42 are connected by the connection wiring 47, and the sides 42a and 42b are connected. The upper electrodes 44 a of the four piezoelectric elements 43 arranged along the line are connected by the connection wiring 48. Each connection wiring 47, 48 is connected to the ground. A signal line 49 is drawn from the lower electrode 44b of each piezoelectric element 43. The signal line 49 is for transmitting the output signal of the electromotive force generated in the piezoelectric film 45 to the coordinate detection circuit 50 shown in FIG. Each signal line 49 is routed on the substrate and collected in one place, and is electrically connected to the coordinate detection circuit 50 via the wiring substrate 51.

  The coordinate detection circuit 50 includes an amplifier 52, an A / D converter 53, and a coordinate calculation unit 54. An output signal output from each piezoelectric element 43 is converted into an electric signal by the amplifier 52 and converted into a digital signal by the A / D converter 53. This digital signal is sent to the coordinate calculation unit 54. The coordinate calculation unit 54 stores the digital signal of each piezoelectric element 43 in a memory (not shown), and compares and calculates the output signal from each piezoelectric element 43. The user's pressing position in the input area X is detected from the calculation result by the coordinate detection circuit 50. That is, the magnitude of the output signal from each piezoelectric element 43 is compared, and the position of the input region X where the deformation of the touch panel substrate 42 occurs is calculated. Since the magnitude of the output signal of the piezoelectric element 43 is proportional to the curvature of the touch panel substrate 42 (piezoelectric element), it can be said that the bending deformation of the touch panel substrate 42 occurs near the piezoelectric element 43 having a large output signal. The position detection sensor of this embodiment is configured including the coordinate detection circuit 50 and the piezoelectric element 43.

Further, as shown in FIG. 1B, a protective film covering the exposed portions of the electrodes 44a and 44b and the piezoelectric film 45 is provided on the piezoelectric element 43 in order to maintain and improve mechanical protection and electrical insulation. 46 is formed. In the present embodiment, for example, (SiO ₂ ), alumina (Al ₂ O ₃ ) or the like is used, and the film thickness is set to about 0.2 μm. The protective film 46 prevents intrusion of reducing substances such as hydrogen (H ₂ ) and water (H ₂ O), thereby preventing the electrodes 44 a and 44 b and the piezoelectric film 45 from deteriorating.

Further, as shown in FIGS. 1A and 1B, the wiring area Y of the input surface 42 </ b> A has a substantially frame in plan view in the vicinity of the piezoelectric element 43 and on the inner side in the surface direction of the substrate than the piezoelectric element 43. Shaped spacers 55 (convex portions) are arranged. The spacer 55 is an interval forming member for forming an interval d between the liquid crystal display panel 30 and the touch panel 40, and is formed above the signal line 49 of the piezoelectric element 43. In FIG. 1, the number of signal lines 49 in the spacer 55 is reduced.
The height of the spacer 55 is higher than that of the piezoelectric element 43, and the upper surface thereof is further away from the input surface 42 </ b> A than the upper surface of the piezoelectric element 43. Thereby, the contact between the cover material 56 provided on the spacer 55 and the piezoelectric element 43 is prevented, and the piezoelectric element 43 can be protected. The cover material 56 is a part of a panel case that accommodates the touch panel 40 and the liquid crystal display panel 30, and is formed of a thin plate formed in a frame shape in plan view, and has a plate width that can cover the wiring region Y of the touch panel substrate 42. Have.

On the other hand, as shown in FIG. 1B and FIG. 2B, the touch panel substrate 42 has a back surface 42B side where a plurality of piezoelectric elements 43 arranged on the input surface 42A side overlap with each other in a plan view. A frame-shaped groove 57 along the edge of the substrate 42 is formed. The groove portion 57 is formed of a concave portion that is recessed from the back surface 42B in the plate thickness direction, the width w of the opening portion 57A is approximately 0.5 μm, and the depth t is within a range of 20 to 70% with respect to the plate thickness of the touch panel substrate 42. Is set.
For example, when the depth t of the groove 57 is less than 20% of the thickness of the touch panel substrate 42, the touch panel substrate 42 becomes difficult to be deformed, and a certain amount of strong pressing force (so that the user consciously presses with pressure) Is necessary). Further, when the depth t of the groove portion 57 exceeds 70% of the thickness of the touch panel substrate 42, the thickness of the groove portion 57 becomes thin, so that the touch panel substrate 42 may be damaged during use and the durability is poor. . Therefore, by setting the depth t of the groove portion 57 to be within 20 to 70% of the plate thickness of the touch panel substrate 42, the touch panel substrate 42 can be more easily deformed than the conventional one, and the durability is ensured.
Note that the width w and the depth t of the groove portion 57 can be appropriately changed according to the material and area of the touch panel substrate 42.

  In the present embodiment, the groove portion 57 is formed so as to overlap with the approximate center of the piezoelectric element 43 in plan view, but as shown in FIG. 4, the groove portion 57 is closer to the outer end portion 43 a of the piezoelectric element 43. May be formed. Thereby, since the amount of change (bending stress) of the piezoelectric element 43 that deforms following the touch panel substrate 42 increases, a larger electromotive force can be obtained even with the same pressing force, and the user inputs information. Responsiveness when doing is good.

[LCD panel]
Next, the configuration of the liquid crystal display panel will be described.
As shown in FIG. 1, in the liquid crystal display panel 30, a color filter substrate 2 and an element substrate 1 disposed to face the color filter substrate 2 are bonded together via a frame-shaped seal member 3. A liquid crystal is sealed between the color filter substrate 2 and the element substrate 1 surrounded by the seal member 3 to form a liquid crystal layer 4 (electro-optical material). The frame-shaped sealing member 3 is mixed with a plurality of conducting members 7 such as gold particles and silver particles.

  The color filter substrate 2 is made of glass or the like, and on the inner surface of the color filter substrate 2, a colored layer 6 made of any of R (red), G (green), and B (blue) is formed. A color filter is constituted by the colored layer 6. A light shielding layer BM is formed between the adjacent colored layers 6 to prevent light from entering.

  A protective layer 18 made of a transparent resin or the like is formed on the colored layer 6 and the light shielding layer BM. The protective layer 18 has a function of smoothing the level difference of the color filter between the respective colors, and also has a function of protecting the colored layer 6 from corrosion and contamination due to chemicals used during the manufacturing process of the liquid crystal display device 100. .

  On the surface of the protective layer 18, a transparent electrode 32 such as striped ITO (Indium Tin Oxide) is formed. One end of the transparent electrode 32 extends into the seal member 3 and is electrically connected to the above-described conducting member 7 in the seal member 3.

  On the other hand, the element substrate 1 is formed of glass or the like, and scanning lines 31 are formed on the inner surface of the element substrate 1 at a constant interval. On the inner surface of the element substrate 1, a TFD (Thin Film Diode) element 21 and a pixel electrode 10 that are switching elements are formed for each sub-pixel. The scanning line 31 is electrically connected to the pixel electrode 10 via the corresponding TFD element 21. The liquid crystal display panel 30 applies gradation between the pixel electrode 10 and the transparent electrode 32 to control the orientation of the liquid crystal in the liquid crystal layer 4, thereby changing the light transmittance and performing gradation display. Here, the switching element is not limited to the TFD element, and a TFT (Thin Film Transistor) element can also be used.

  On the outer surface side of the element substrate 1 (surface opposite to the liquid crystal layer 4), an illumination device 20 that functions as a backlight is disposed. The illuminating device 20 includes a light source, specifically, an LED (Light Emitting Diode) as a point light source, and a light guide that converts the point light emitted from the LED into a planar shape and emits the light. The light emitted from each LED is introduced into the light guide, and is emitted in the direction of the liquid crystal display panel 30 from the light emission surface of the light guide as planar light.

  The touch panel 40 of this embodiment is joined to the liquid crystal display panel 30 with an adhesive. Specifically, as shown in FIG. 1A, an optical elastic adhesive film disposed between the touch panel substrate 42 and the back surface 42B of the touch panel substrate 42 facing the outer surface 2A of the color filter substrate 2 of the liquid crystal display panel 30. 58 is bonded. The optical elastic adhesive film 58 is made of a transparent adhesive applied in a solid shape on the outer surface 2A of the color filter substrate 2. Here, the optical elastic adhesive film 58 may be formed on the back surface 42 </ b> B side of the touch panel substrate 42, but it is easier to deform when the adhesive material does not enter the groove portion 57, and the groove portion 57 is embedded with the adhesive material. Since the pressing force at the time of input can be made smaller than the case, it is preferably formed on the color filter substrate 2 side. However, in the case where the optical elastic adhesive film 58 is made of an adhesive tape, the groove 57 is not embedded with an adhesive material, so that the input pressure can be reduced.

  In addition, by arranging the optical elastic adhesive film 58 having a refractive index substantially equal between the touch panel substrate 42 and the color filter substrate 2, Newton's ring can be prevented from occurring.

  The integrated touch panel 40 and the liquid crystal display panel 30 are accommodated in a panel case having the cover material 56. In this way, the liquid crystal display device 100 having a touch panel function is configured.

Fig.5 (a) is a schematic diagram which shows a mode that a user presses the touch panel 40 with a finger | toe, FIG.5 (b) is a schematic diagram which shows the deformation | transformation state of a piezoelectric element and a groove part at the time of a press. In the following description, FIG. 3 will be referred to as appropriate.
As shown in FIG. 5A, when the user presses a place with a certain characteristic on the input surface 42A with, for example, a finger, the touch panel substrate 42 bends toward the liquid crystal display panel 30 around the pressed position, and the optical elastic adhesive film 58 is deformed so as to change its film thickness along with the deformation of the touch panel substrate 42. At this time, the impact at the time of pressing is relieved by the optical elastic adhesive film 58.

  When the touch panel substrate 42 is pressed, as shown in FIG. 5B, the width direction of the opening 57A in the groove 57 is compressed, and the deformation of the touch panel substrate 42 is allowed by narrowing the opening width. The presence of the groove 57 facilitates the deformation of the touch panel substrate 42.

  On the other hand, as shown in FIG. 5 (b), the plurality of piezoelectric elements 43 provided on the touch panel substrate 42 are each bent along with the change in the curvature of the touch panel substrate 42 simultaneously with the deformation of the touch panel substrate 42. Although the curvature of the touch panel substrate 42 varies depending on the pressing means, the pressing position, the pressing force, and the like, the piezoelectric element 43 can be deformed following the deformation of the touch panel substrate 42.

  Due to the deformation, the piezoelectric element 43 generates an electromotive force (bending force) corresponding to the deformation amount. The piezoelectric film 45 in the piezoelectric element 43 reacts well when a tensile force is applied, and generates a large electromotive force when pulled in the stretching direction at the time of manufacture. Electric power will be generated. Therefore, each piezoelectric element 43 located at a predetermined location on the touch panel substrate 42 generates an electromotive force in a bending mode according to the pressing position and pressing force by the user. Here, it is preferable that the piezoelectric elements 43 are arranged so that the extending direction at the time of manufacturing the piezoelectric film 45 is orthogonal to the corresponding sides of the touch panel substrate 42.

  Based on output signals from the piezoelectric elements 43, the coordinate detection circuit 50 shown in FIG. 3 detects the pressing position of the input surface 42A by the user. Specifically, by comparing the magnitudes of the output signals of the four piezoelectric elements 43 arranged in the x direction of the touch panel substrate 42, the x coordinate of the pressed location is specified and arranged in the y direction of the touch panel substrate 42. By comparing the magnitudes of the output signals of the four piezoelectric elements 43, the y-coordinate of the pressed location is specified. Thus, the coordinate detection circuit 50 can calculate the x coordinate and the y coordinate of the position pressed by the user based on the magnitude of the output signal from each piezoelectric element 43.

  Since the gap d is provided by the spacer 55 between the piezoelectric element 43 and the cover material 56, the piezoelectric element 43 and the cover material 56 are prevented from coming into contact with each other due to deformation, and the output of the piezoelectric element 43 is prevented. Will not be affected.

  According to the present embodiment, when the input surface 42A of the touch panel substrate 42 is pressed by the user, even if the pressing force is small (when lightly touched), the touch panel substrate 42 can be easily used with the groove portion 57 as a base point. Transforms into That is, when the opening side of the groove portion 57 is compressed by the pressing, the opening portion 57A is reduced and deformed, and the touch panel substrate 42 is allowed to be deformed. Unlike the conventional configuration in which the entire substrate is uniformly deformed at the time of pressing, in this embodiment, the curvature of the touch panel substrate 42 at the pressing portion can be greatly changed. When the touch panel substrate 42 is deformed, the piezoelectric element 43 is simultaneously deformed following the deformation, and an electromotive force is generated according to the deformation amount. Therefore, the pressing position of the user on the input surface 42A (input area X) is detected by comparing the magnitudes of the output signals from the respective piezoelectric elements 43 arranged on the sides 42a to 42d of the touch panel substrate 42. Can do.

  In addition, since the electromotive force generated by the piezoelectric element 43 is used as a means for detecting the pressed position, the current consumption can be reduced, and the pressed position can be accurately detected even when a pen other than the user's finger is used. It can be detected well. Moreover, since it is only necessary to attach the piezoelectric element 43 to the touch panel substrate 42, installation work is easy.

Further, since the impact at the time of pressing is relieved by the optical elastic adhesive film 58, the impact resistance of the touch panel substrate 42 is improved and the durability becomes high.
Furthermore, since the spacer 55 is formed on the connection wirings 47 and 48 and disposed inside the piezoelectric element 43, the frame width of the touch panel 40 can be reduced, and the touch panel substrate 42 can be downsized. .
Therefore, according to this embodiment described above, the liquid crystal display device 100 including the touch panel 40 with a simple configuration and high detection accuracy of the pressed position can be obtained.

  In the present embodiment, the upper electrode 44a is a common electrode and the lower electrode 44b is an individual electrode. However, there is no problem even if it is reversed for reasons of configuration. The upper electrodes 44a of all the piezoelectric elements 43 arranged on the touch panel substrate 42 may be used as a common electrode. This simplifies the configuration and facilitates formation. Further, as the piezoelectric element 43, a piezoelectric film coated with a commercially available metal powder film-containing paint can be used.

(Second Embodiment)
FIG. 6A is a cross-sectional view showing the overall configuration of the liquid crystal display device according to the second embodiment, and FIG. 6B is an enlarged cross-sectional view showing the configuration of the notch. Fig.7 (a) is a top view which shows the back surface side of a touchscreen board | substrate, FIG.7 (b) is a schematic diagram which shows the deformation | transformation state of a piezoelectric element and a groove part at the time of a press.
This embodiment is different from the above embodiment in that the touch panel and the liquid crystal display substrate are joined via a spacer. The other basic configuration of the liquid crystal display device is the same as that of the above embodiment, and common constituent elements are denoted by the same reference numerals and detailed description thereof is omitted.

As shown in FIG. 6A, in the liquid crystal display device 200 (display device), the touch panel 40 and the liquid crystal display panel 30 are joined via a spacer 55. In the present embodiment, the groove portion 57 is formed on the input surface 42A side, and the piezoelectric element 43 is disposed on the back surface 42B side. The piezoelectric element 43 is inside the spacer 55 and is interposed between the spacer 55 and the optical elastic adhesive film 58. A space d is provided by the spacer 55 between the piezoelectric element 43 and the color filter substrate 2.
In addition, by setting the height of the spacer 55 to be equal to or higher than the height of the piezoelectric element 43 and providing a predetermined interval between the touch panel 40 and the liquid crystal display panel 30, the occurrence of Newton rings can be prevented.

  The optical elastic adhesive film 58 is formed in a range that covers at least the display area of the liquid crystal display panel 30 (input area X of the touch panel), and a plurality of piezoelectric elements 43 around the touch panel substrate 42 as in the above embodiment. Two are arranged for each side. Also in this embodiment, the spacer 55 may be formed so as to include a plurality of signal lines 49 drawn from the piezoelectric element 43 as shown in FIG. Furthermore, the signal lines 49 of the present embodiment are routed around the periphery of the touch panel substrate 42 and collected on one side of the side 42c, and are connected to the coordinate detection circuit via the wiring substrate.

  As shown in FIG. 6A, the frame-shaped groove portion 57 is formed at a position overlapping with each piezoelectric element 43 in plan view. In the present embodiment, since the groove portion 57 is opened outward, dust or the like easily enters the groove portion 57. In order to prevent this, a blocking member (not shown) that closes the opening 57 </ b> A may be provided on the groove 57. The closing member is made of a material that expands and contracts following the deformation of the groove portion 57.

  Further, a notch 63 for fitting with a panel case (not shown) is formed on the outer periphery of the groove 57 and on the periphery of the touch panel 40. As shown in FIG. 6B, the notch 63 has a bottom surface 63a having a height different from the input surface 42A in the thickness direction, and a wall surface 63b that forms a step between the input surface 42A and the bottom surface 63a. It consists of and. By incorporating the cover material 56 into the notch 63, the integrated touch panel 40 and the liquid crystal display panel 30 are accommodated in the panel case. After the accommodation, the input surface 42A of the touch panel 40 and the upper surface of the cover material 56 are flush with each other. At the time of accommodation, the position in the width direction of the touch panel 40 with respect to the panel case is regulated by bringing the side surface 56c of the cover material 56 into contact with the wall surface 63b of the notch 63. Further, by bringing the back surface 56b of the cover material 56 into contact with the bottom surface 63a of the notch 63, the position of the touch panel 40 in the depth direction with respect to the panel case is regulated. The notch 63 of the present embodiment has a function of positioning the touch panel 40 and the liquid crystal display panel 30 with respect to the panel case.

  Further, when the input surface 42A of the touch panel 40 of the present embodiment is pressed by the user, the touch panel substrate 42 is bent toward the liquid crystal display panel 30 around the pressed position. At this time, the input surface of the touch panel 40 Since a tensile force is applied to the 42A side, the opening 57A of the groove 57 expands. The expansion of the opening 57A allows the touch panel substrate 42 to be deformed, and the curvature of the pressed portion changes greatly. Therefore, also in the present embodiment, the pressed position can be detected with high accuracy as in the above-described embodiment.

  According to the present embodiment, the input surface 42A of the touch panel substrate 42 and the outer surface of the panel case are flush with each other, and the apparent area of the input region X increases. Furthermore, since there is no level difference on the touch panel 40, the design is improved and dust and the like are not easily collected and cleaning is facilitated. In addition, since the touch panel can be made thin, the entire apparatus can be downsized. Furthermore, since the touch panel 40 and the liquid crystal display panel 30 are positioned with respect to the panel case simply by incorporating the cover material 56 into the notch 63, the touch panel 40 and the liquid crystal display panel 30 are easily and accurately aligned with respect to the panel case. be able to.

[Example]
8 and 9 and Table 1 show the relationship between the pressed position and the electromotive force of each piezoelectric element. FIG. 8 is a plan view showing the touch position of the user in the input area X of the touch panel substrate. (A) to (c) of FIG. 9 are graphs showing the value of the electromotive force of each piezoelectric element for each pressed position. Further, Table 1 is a table in which output results from each piezoelectric element are summarized for each pressing position.
Hereinafter, description will be made with reference to FIGS.

  The pressing positions P1 and P2 are corners of the input region X and are very close to the two piezoelectric elements A and E, and the deformation of the touch panel substrate is most reflected in these piezoelectric elements A and E, and is caused by bending. The amount of deformation is larger than that of other piezoelectric elements. In FIG. 9A and Table 1, since the outputs of the piezoelectric elements A and E are significantly larger than those of the other piezoelectric elements, it is clear that an electromotive force is generated according to the bending deformation amount of each piezoelectric element. It is.

  The pressing position P3 is substantially in the center of the input area X and slightly from the piezoelectric element E. As shown in FIG. 9B, the output of each piezoelectric element at the pressing position P3 is the largest, and the outputs of the piezoelectric elements F, G, and H arranged in the longitudinal direction of the input region X are as follows. The output is less than half of the output of the piezoelectric element E, but all three outputs are almost equal. Further, the outputs of the piezoelectric elements A, B, C, and D arranged in the short direction of the input region X are substantially equal, and are approximately half or less than the outputs of the piezoelectric elements F, G, and H.

  That is, when the input area X (touch panel substrate) has a rectangular shape, the longitudinal direction is easily bent when the input area X is pressed. Therefore, the output of the piezoelectric elements E, F, G, and H arranged along the longitudinal direction of the input region X is more than the output of the piezoelectric elements A, B, C, and D arranged along the short direction. Also grows. Further, since the output of the piezoelectric element E is the largest, it can be seen that the pressing position is shifted from the center of the input region X to the piezoelectric element E side.

FIG. 10 shows a simulation result representing the deformation of the touch panel substrate when the user presses the pressing position P4.
As shown in FIG. 10, the darker the color, the greater the curvature of deformation. The change in curvature differs depending on the distance from each side of the input area X (touch panel substrate) to the pressing position P4. The smaller the distance between the pressing position P4 and the side, the larger the change in curvature, and the difference between the pressing position P4 and the side. It can be seen that the greater the distance, the smaller the curvature change and the gentle deformation. Further, the change in the curvature of the touch panel substrate is also related to the longitudinal direction and the short direction of the input screen as described above. In Example 4, the output difference for each piezoelectric element is clear and represents a complicated deformation state of the touch panel substrate.

  Thus, the output from each piezoelectric element differs depending on the pressing position. Comparing the outputs from these piezoelectric elements, it can be seen that the touch panel substrate is bent and deformed at the position of the piezoelectric element that outputs the largest piezoelectric signal. That is, it can be estimated that the location where the curvature deformation of the touch panel substrate is the largest is the pressed position. In this way, it is possible to detect the pressed position by the user.

  In the above embodiment, two piezoelectric elements 43 are arranged on each side of the touch panel substrate 42. However, the present invention is not limited to this. One piezoelectric element 43 may be arranged on each side, or two or more piezoelectric elements 43 may be arranged on each side. May be. Further, the number of piezoelectric elements 43 may be different for each side. The number and position of the piezoelectric elements 43 are appropriately set depending on the area and shape of the touch panel substrate 42.

In the above embodiment, the frame-shaped groove portion 57 is used. However, the groove portion 57 may be divided in the middle (for example, in the vicinity of the corner portion), and may be composed of a plurality of groove portions 67 as shown in FIG. . Further, a plurality of groove portions may be provided side by side in the surface direction of the substrate. For example, as shown in FIG. 11 (b), frame-shaped grooves 69a and 69b having different sizes may have a double structure with a predetermined interval therebetween. Thereby, since the deformation amount of the touch panel substrate 42 increases, the electromotive force from the piezoelectric element can be increased, and the stress load on the grooves 69a and 69b due to the deformation is dispersed, so that the durability of the touch panel substrate 42 is improved.
Moreover, the corner | angular part of a groove part may be round frame shape, and the shape in planar view may be elliptical.

  Furthermore, the spacer is not limited to the above embodiment, and may be divided into a plurality of parts. In that case, a spacer is arranged at least in the vicinity of each piezoelectric element.

  Moreover, although the cross section of the groove part 57 of the said embodiment was substantially square shape, as shown to Fig.12 (a)-(d), the shape in a cross sectional view is the groove part 57a of a wedge shape, and an opening end is a wide mouth. A trapezoidal groove 57b, a trapezoidal groove 57c having a narrow opening end, a U-shaped groove 57d, or the like may be used. Moreover, as shown in FIG.12 (e), you may make it provide the cavity part 70 in a touchscreen board | substrate instead of a groove part. Further, the shape of the cavity 70 is not particularly limited.

[Electronics]
Next, an example of the electronic device of the present invention will be described.
FIG. 13 is a perspective view showing a mobile phone (electronic device) including the liquid crystal display device 100 having the touch panel function described above.
As shown in FIG. 13, the mobile phone 600 includes a first body 106 a and a second body 106 b that can be folded around a hinge 122. The first body 106a is provided with a liquid crystal display device 601, a plurality of operation buttons 127, an earpiece 124, and an antenna 126. The second body 106b is provided with a mouthpiece 128.
According to the electronic apparatus according to the present embodiment, since the liquid crystal display device 100 in which malfunction is prevented and scattering of the glass (touch panel substrate, first touch panel substrate) of the touch panel is prevented is provided, high performance and high reliability are achieved. A mobile phone 600 can be provided.

  Note that the liquid crystal display device 100 having the touch panel function described above can be applied to various electronic devices other than the mobile phone. For example, LCD projectors, multimedia-compatible personal computers (PCs) and engineering workstations (EWS), pagers, word processors, TVs, viewfinder type or monitor direct view type video tape recorders, electronic notebooks, electronic desk calculators, car navigation systems The present invention can be applied to electronic devices such as a device, a POS terminal, and a device provided with a touch panel.

  The preferred embodiments according to the present invention have been described above with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to such examples, and the above embodiments may be combined. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  For example, the touch panel according to the first embodiment and the touch panel according to the second embodiment can be attached not only to the liquid crystal display device described above but also to other display devices such as an organic EL display device. Needless to say.

(A) is sectional drawing which shows the whole structure of the liquid crystal display device which is an example of the display apparatus which concerns on this invention, (b) is a principal part enlarged view of a touch panel. (A) is a top view which shows the input surface side of a touchscreen board | substrate, (b) is a top view which shows the back surface side of a touchscreen board | substrate. The figure which shows the internal structure of a touchscreen. The figure which shows the other example of the arrangement position in a groove part. (A) is a schematic diagram which shows a mode that a user presses a touch panel with a finger, (b) is a schematic diagram which shows the deformation | transformation state of a piezoelectric element and a groove part at the time of a press. (A) Sectional drawing which shows the whole structure of the liquid crystal display device in 2nd Embodiment, (b) is a principal part enlarged view of (a). (A) is a top view which shows the back surface side of a touchscreen board | substrate, (b) is a schematic diagram which shows the deformation | transformation state of a piezoelectric element and a groove part at the time of a press. The figure which shows the press position in an input area. (A)-(c) is a graph which shows the value of the electromotive force of each piezoelectric element for every pressing position. The figure which shows the simulation result when a user presses the press position P4. The top view which shows other embodiment of a groove part. Sectional drawing which shows other embodiment of a groove part. 1 is a schematic configuration diagram of a projector that is an example of an electronic apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Liquid crystal display device, 1 ... Element substrate, 2 ... Substrate, 2A ... Outer surface, 3 ... Member, 4 ... Liquid crystal layer, 6 ... Colored layer, 7 ... Conductive member, AG ... Piezoelectric element, d ... Space | interval, w Opening width, 10 ... Pixel electrode, 18 ... Protective layer, 20 ... Illumination device, 21 ... Element, 30 ... Liquid crystal display panel, 31 ... Scanning line, 32 ... Transparent electrode, 40 ... Touch panel, 42 ... Substrate, 42A ... Input Surface, 42B ... Back surface, 42a, 42b, 42c, 42d ... Side, 43 ... Piezoelectric element, 43a ... End, 44a ... Upper electrode, 44b ... Lower electrode, 45 ... Piezoelectric film, 46 ... Protective film, 47, 48 ... connection wiring, 49 ... signal line, 50 ... coordinate detection circuit, 51 ... wiring board, 52 ... amplifier, 53 ... converter, 54 ... coordinate calculation part, 55 ... spacer (convex part), 56 ... cover material, 56b ... Back surface, 56c ... side surface, 57 ... groove, 57A ... opening, 5 DESCRIPTION OF SYMBOLS Optical elastic adhesive film 63 ... Notch part 63a ... Bottom surface, 63b ... Wall surface, 70 ... Hollow part, BM ... Light-shielding layer, 100 ... Liquid crystal display device (display device), 106a ... Body, 106b ... Body, 122 ... Hinge , 124 ... Earpiece, 126 ... Antenna, 127 ... Button, 128 ... Mouthpiece, 200 ... Liquid crystal display device (display device), 600 ... Mobile phone (electronic device), 601 ... Liquid crystal display device

Claims (13)

A touch panel substrate having an input surface;
A piezoelectric element disposed on either the input surface or the back surface of the touch panel substrate,
The piezoelectric element is disposed at least one part on each side of the touch panel substrate,
A touch panel, wherein a groove portion is formed on a surface of the touch panel substrate opposite to the piezoelectric element at least at a position overlapping the piezoelectric element in plan view.   The touch panel according to claim 1, wherein the groove has a frame shape along an edge of the touch panel substrate.   The touch panel according to claim 1, wherein a plurality of the piezoelectric elements are arranged on each side of the touch panel substrate.   The depth of the said groove part exists in the range of 20 to 70% with respect to the thickness of the said touch panel substrate, The touch panel as described in any one of Claims 1 thru | or 3 characterized by the above-mentioned. The piezoelectric element has a first electrode, a piezoelectric film and a second electrode laminated on the touch panel substrate,
The touch panel according to claim 1, wherein the piezoelectric film includes at least one of ZnO, AlN, PZT, LiNbO ₃ , LiTaO ₃ , and KNbO ₃ . A protective film is provided on the piezoelectric element,
The touch panel according to claim 1, wherein the protective film is made of SiO ₂ or Al ₂ O ₃ .   The convex part which is arrange | positioned on the same surface and the vicinity of the said piezoelectric element, and has a height higher than the said piezoelectric element on the wiring connected to the said piezoelectric element is characterized by the above-mentioned. The touch panel according to item.   8. The touch panel substrate according to claim 1, further comprising a cutout portion formed on the outside of the groove on the input surface, the cutout portion being fitted with another component member to which the touch panel is mounted. The touch panel as described in any one. A touch panel substrate having an input surface;
A piezoelectric element disposed on either the input surface or the back surface of the touch panel substrate,
The piezoelectric elements are arranged at least one on each side of the touch panel substrate,
In the touch panel substrate, a hollow portion is formed at a position overlapping the piezoelectric element in plan view. A display device comprising the touch panel according to any one of claims 1 to 9 and a display panel,
The display panel includes: a pair of substrates; and an electro-optical material sandwiched between the pair of substrates.   The display device according to claim 10, wherein the touch panel and the display panel are arranged to face each other via a convex portion formed on the touch panel.   The display device according to claim 10, wherein the touch panel and the display panel are joined by an optical elastic adhesive film.   An electronic apparatus comprising the display device according to any one of claims 10 to 12.

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