JP2006285420A - Touch panel and touch panel type coordinate input method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch panel using surface acoustic wave capable of avoiding deterioration in position detecting accuracy caused by the adhesion of a foreign matter to an operation surface, and a touch panel type coordinate input method for detecting a coordinate position using the touch panel. <P>SOLUTION: The touch panel 1 comprises a flexible transparent substrate 11 having a surface acoustic wave propagation surface 22 at a side opposed to a contacted member 2 located opposite to the operation surface 21 to be touch-operated. The position of the touch-operation is detected based on the change of surface acoustic wave propagating state which is caused when the propagation surface 22 of the transparent substrate distorted by the touch operation of the operation surface 21 contacts with the contacted member 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a touch panel using surface acoustic waves and a touch panel type coordinate input method for detecting a coordinate position using the touch panel.

  A touch panel using a surface acoustic wave (SAW) (hereinafter simply referred to as “SAW touch panel”) has a higher light transmittance than a resistive film type touch panel, so that a clearer image can be obtained. It is possible to display. Further, the vicinity of the screen area where the touch operation is performed is configured by a plurality of layers in a resistive film type touch panel. However, since the SAW touch panel can be configured by a single glass substrate, the touch panel can be easily downsized. (For example, refer to Patent Document 1).

  FIG. 8 is a sectional view showing a conventional example of a touch panel using surface acoustic waves, and FIG. 9 is a top view showing a conventional example of a touch panel using surface acoustic waves. FIG. 10 is an exploded perspective view showing a transducer for realizing the surface acoustic wave generating means and the surface acoustic wave detecting means.

  In the SAW touch panel 50, a transparent substrate 51 for propagating surface acoustic waves is provided above the display screen of the display device 2 such as an LCD. The transparent substrate 51 is made of a glass substrate. Of the four sides of the transparent substrate 51 having a substantially quadrangular operation surface, surface acoustic wave generating means 52 is provided on two opposing sides on the operation surface, and surface acoustic wave detecting means 52 is provided on the remaining two sides. Provided. The surface acoustic wave generating means 52 transmits the surface acoustic wave so as to propagate on the operation surface in a direction substantially parallel to the diagonal line of the operation surface (indicated by a dotted arrow in the figure). Generate elastic waves.

  The surface acoustic wave generating means 52 and the surface acoustic wave detecting means 53 can be realized by a transducer 60 having the same structure on the transparent substrate 2 as shown in FIG. The transducer 60 has an SPT (Single Phase Transducer) electrode structure in which a piezoelectric thin film 61 is sandwiched between a short-circuit electrode 62 and an array of unipolar comb-shaped electrodes 63.

  The piezoelectric thin film 61 has a property of causing electric polarization when stress is applied and generating distortion or stress when an electric field is applied. The SAW touch panel 50 uses this property to generate and detect surface acoustic waves (SAW). The comb electrode 63 is a chevron electrode having a dogleg shape. A plurality of comb-shaped electrodes 63 are continuously arranged, and each of them is connected via a bus electrode 64.

  As shown in FIG. 9, the surface acoustic wave generating means 52 always generates surface acoustic waves so that the surface acoustic waves propagate on the operation surface in a direction substantially parallel to the diagonal line of the operation surface. On the other hand, the surface acoustic wave detection means 53 always receives the surface acoustic waves sent from the surface acoustic wave generation means 52. At this time, when a touch operation is performed on the operation surface using, for example, a finger or a stylus pen, the propagation of the surface acoustic wave is blocked at the location where the touch operation is performed, and the propagation state of the surface acoustic wave is changed. The SAW touch panel 50 detects the change information of the propagation state of the surface acoustic wave, calculates the detection result, and detects the position of the touch operation.

  In addition, a touch panel using a piezoelectric ceramic as the piezoelectric member has already been proposed (see, for example, Patent Document 2).

Japanese Patent No. 3010669 JP-A-10-55246

  In a conventional SAW touch panel, an operation surface on which surface acoustic waves are propagated is touch-operated using a finger or a stylus pen, and the propagation state of surface acoustic waves at the touch-operated portion generated at this time is based on a change. Thus, the position of the touch operation is detected. For this reason, the propagation state of the surface acoustic wave also changes when foreign matter such as water droplets or dust adheres to the operation surface of the transparent substrate. This leads to a decrease in position detection accuracy. Although there is a method of compensating for such a decrease in position detection accuracy by arithmetic processing, a sufficient effect has not been obtained and the processing contents are complicated.

  Accordingly, an object of the present invention is to provide a touch panel using surface acoustic waves and a touch panel type coordinate input method for detecting a coordinate position using the touch panel, which avoids a decrease in position detection accuracy due to foreign matters adhering to the operation surface in view of the above problems. Is to provide.

  In order to achieve the above object, in the present invention, the transparent substrate is formed of a flexible member. Then, the surface acoustic wave is propagated to the surface opposite to the operation surface on which the touch operation is performed on the transparent substrate. That is, the surface opposite to the operation surface is a propagation surface on which surface acoustic waves propagate. Further, the contacted member is installed so as to face the propagation surface of the transparent substrate so as to have a predetermined interval with respect to the propagation surface.

  In other words, according to the present invention, the surface elastic wave whose propagation surface is the surface facing the contacted member located on the opposite side of the operation surface of the flexible transparent substrate has a transparent surface that is deflected by touch operation of the operation surface. The position of the touch operation is detected based on a change in the propagation state that occurs when the propagation surface of the substrate contacts the contacted member. The contacted member is, for example, a display screen.

  According to the present invention, surface acoustic waves are not propagated to the operation surface of the transparent substrate of the SAW touch panel, and the surface opposite to the operation surface is used as the surface acoustic wave propagation surface. Even if a foreign matter such as a foreign substance adheres, the position detection accuracy does not decrease. In the first place, since the surface of the surface acoustic wave propagation faces the contacted member so as to have a predetermined interval, it is difficult for foreign matter to adhere to the propagation surface.

  Further, in the conventional SAW touch panel, it was impossible to stick a film on the operation surface because surface acoustic waves had to be propagated on the operation surface. However, in the SAW touch panel according to the present invention, Since the surface acoustic wave is not propagated in the case, a cover film can be separately attached to the operation surface. In other words, for example, a film having various functions such as a film that prevents scattering of fragments due to the cracking of the transparent substrate, an antiglare film, or a film having a polarizing function can be attached. Easy to expand functions.

  Furthermore, conventional SAW touch panels absorb surface acoustic waves such as fingers or rubber when touched with a material that does not absorb surface acoustic waves such as the tip of a fingertip, metal pen, or plastic pen. When the touch operation is performed with an easy-to-use material, the input load on the operation surface during the touch operation is different, so the feeling of use is different. In particular, when a touch operation was performed with a material that hardly absorbs surface acoustic waves, the sensitivity was low and the usability was poor. On the other hand, in the present invention, the propagation surface of the transparent substrate bent by the touch operation of the operation surface is caused by contact with the contacted member, that is, the propagation of the surface acoustic wave is always blocked. Because the member comes into contact with the propagation surface, it can be applied with almost the same input load regardless of whether it is made of a material that hardly absorbs or absorbs surface acoustic waves. Since the touch operation can be performed, variation in feeling of use can be suppressed.

  FIG. 1 is a top view of a SAW touch panel according to an embodiment of the present invention. 2 is a cross-sectional view of the SAW touch panel according to the embodiment of the present invention, taken along line AA in FIG.

  A SAW touch panel 1 according to an embodiment of the present invention includes a transparent substrate 11 having flexibility. In the transparent substrate 11, a surface facing the contacted member 2 located on the side opposite to the operation surface 21 to be touched is defined as a surface acoustic wave propagation surface 22. On the side of the transparent substrate 11 facing the propagation surface 22, the contacted member 2 is installed so as to have a predetermined distance from the propagation surface 22. The contacted member 2 is a display screen of a display device such as a CRT, LCD, EL, or PDP.

  The transparent substrate 11 is a transparent glass substrate, for example. However, the present invention is not limited to this, and a member having a certain degree of light transmittance and capable of transmitting a weak surface energy wave and having a hardness that causes a certain degree of bending when touched. Any substrate may be used. For example, a substrate made of a member such as acrylic or polycarbonate is also applicable.

  In the present embodiment, the operation surface 21 and the propagation surface 22 of the transparent substrate 11 have a substantially rectangular shape. Moreover, the thickness of the transparent substrate 11 should just be a thing which can contact the to-be-contacted member 2 installed with the said predetermined | prescribed space | interval, when the operation surface 21 of the transparent substrate 11 is touch-operated. . For example, the thickness of the transparent substrate 11 may be about one hundredth to several hundredths of the diagonal length of the operation surface 21 of the transparent substrate. For example, the thickness of the transparent substrate 11 having the operation surface 21 having a diagonal length of 10 cm is about 0.3 to 0.5 mm, and the predetermined interval in this case is, for example, 50 μm.

  The SAW touch panel 1 includes a surface acoustic wave generation unit 12 that generates a surface acoustic wave so as to propagate through the propagation surface 22 of the transparent substrate 11, and a surface acoustic wave detection that detects the surface acoustic wave generated by the surface acoustic wave generation unit 11. Means 13. Of the four sides of the propagation surface 22 of the transparent substrate 11, the surface acoustic wave generating means 12 is provided on the two opposite sides, and the surface acoustic wave detecting means 13 is provided on the remaining two sides. That is, in the present invention, since the propagation surface 22 of the transparent substrate 11 is on the opposite side of the operation surface 21, the surface acoustic wave generation means 12 and the surface acoustic wave detection means 13 are provided on the operation surface as in the conventional example. Instead, it is provided on the propagation surface 22 opposite to the operation surface 21. The surface acoustic wave generating means 12 generates a surface acoustic wave to propagate in a direction substantially parallel to the diagonal line of the propagation surface 22 (indicated by a dotted arrow in FIG. 1).

  In the present invention, when the operation surface 21 of the transparent substrate 11 is touch-operated and the transparent substrate 11 is bent and the propagation surface 22 comes into contact with the contacted member 2, the propagation state of the surface acoustic wave propagating through the propagation surface 22 is The position of the touch operation is detected based on this change. That is, the surface acoustic wave detection means 13 detects the change information of the propagation state of the surface acoustic wave, calculates the detection result, and detects the position of the touch operation.

  FIG. 3 is a cross-sectional view of a transducer in a SAW touch panel according to an embodiment of the present invention.

  Each of the surface acoustic wave generation means 12 and the surface acoustic wave detection means 13 has a transducer structure having an SPT (Single Phase Transducer) electrode structure in which the piezoelectric thin film 61 is sandwiched between the short-circuit electrode 62 and the array of unipolar comb-shaped electrodes 63. As described with reference to FIG.

  A sound absorbing material 31 is provided on the propagation surface 22 of the transparent substrate 11 on the side opposite to the side where the surface acoustic wave generating means 12 and the surface acoustic wave detecting means 13 (that is, the transducer 60) face each other. The bus electrode 64 and the routing wiring 32 are provided on the side opposite to the side where the transducers 60 face each other. The sound absorbing material 31 is provided so as to cover at least a part of the bus electrode 64 and the routing wiring 32. It is done. The sound absorbing material 31 is made of an insulator, and is made of, for example, a material to which a rubber packing material is attached or a material formed of a printing resist.

  The surface acoustic wave detection unit 13 directly receives the surface acoustic wave generated by the surface acoustic wave generation unit 12 and propagated through the propagation surface 22 (a surface layer portion of, for example, about 0.1 mm from the surface of the transparent substrate 11). However, the surface acoustic wave generated by the surface acoustic wave generation means 12 is likely to be reflected near the end of the propagation surface 22 of the transparent substrate 11, and if the surface acoustic wave detection means 13 receives this reflected wave as well. The position detection accuracy will be affected. The sound absorbing material 31 is for preventing this. In the present embodiment, the sound absorbing material 31 also has a function of a support member that supports the transparent substrate 11 on the contacted member 2.

  According to the embodiment of the present invention described above, the surface acoustic wave is not propagated to the operation surface 21 of the transparent substrate 11 of the SAW touch panel 1, and the surface opposite to the operation surface 21 is used as the surface acoustic wave propagation surface 22. Therefore, even if foreign matter such as water droplets or dust adheres to the operation surface 21 side, the position detection accuracy does not decrease. In addition, since the surface acoustic wave propagation surface 22 faces the contacted member 2 so as to have a predetermined interval, it is difficult for foreign matter to adhere to the propagation surface 22.

  Next, a modification of the embodiment of the present invention will be described.

  FIG. 4 is a cross-sectional view showing a first modification of the SAW touch panel according to the embodiment of the present invention.

  The SAW touch panel 1 according to the first modification is obtained by attaching a cover film 14 such as a plastic film on the operation surface 21. The cover film 14 preferably has a sufficiently high light transmittance.

  For example, the cover film 14 may be a film for preventing scattering of fragments due to the transparent substrate 11 being broken. Accordingly, it can also be used as a touch panel for devices that require impact resistance, such as mobile devices such as PDAs, mobile phones, and notebook computers, and in-vehicle devices such as car navigation systems and car audio.

  For example, the cover film 14 may be an antiglare-treated film. Anti-glare treatment is a treatment that causes irregular reflection on the surface portion so that light is irregularly reflected, and is applied to devices that do not like the phenomenon of direct reflection of light, such as the display of a car navigation system. . In a conventional SAW touch panel, surface acoustic waves propagate on the operation surface, so it is not preferable to perform anti-glare treatment on the operation surface, and it is necessary to etch a transparent substrate (for example, a glass substrate) even if anti-glare treatment is performed. Manufacturing was troublesome. However, in the present invention, the cover film 14 can be stuck on the operation surface 21 of the transparent substrate 11. Therefore, if the cover film 14 is an anti-glare film, the effect of the anti-glare process can be easily enjoyed. be able to. For example, a commercially available antiglare-treated film may be used.

  For example, the cover film 14 may be a film having a polarization function. In particular, when the member to be contacted is an LCD, a film having a polarizing function is required, but by sticking this to the operation surface, an inner touch panel can be obtained.

  Furthermore, a film having functions other than those described above may be used as the cover film 14. Alternatively, several films having various functions as described above may be laminated to form the cover film 14. Alternatively, a single film having a plurality of various functions at the same time may be used as the cover film 14.

  According to the first modification described above, films having various functions can be stuck on the operation surface 21 of the transparent substrate 11, so that the functions of the SAW touch panel 1 can be easily expanded.

  FIG. 5 is a perspective view showing a second modification of the SAW touch panel according to the embodiment of the present invention. In the second modification, support members 15 that support the transparent substrate 11 on the contacted member 2 are further provided at the four corners on the propagation surface side having a substantially rectangular shape of the transparent substrate 11. For example, in the transparent substrate 11 having an operation surface with a diagonal length of 10 cm, the height of the support member may be about 0.1 mm.

  FIG. 6 is a perspective view showing a third modification of the SAW touch panel according to the embodiment of the present invention. FIG. 7 is a cross-sectional view taken along line AA showing a third modification of the SAW touch panel according to the embodiment of the present invention.

  As already described, in the present invention, the transparent substrate 11 is a substrate made of a member having a hardness that causes a certain degree of bending when a touch operation is performed, for example, a glass substrate. When the operation surface 21 of the transparent substrate 11 is touched, the transparent substrate 11 bends, and the propagation surface 22 of the transparent substrate 11 must come into contact with the contacted member 2 installed with a predetermined interval. Therefore, in the third modified example, in order to make the bending more reliable, the transparent substrate 11 having the propagation surface 22 having a substantially square shape has the thickness of the portion serving as the operation surface 21 set to the propagation surface 22. While maintaining a uniform plane, the transparent substrate 11 has a structure that is thinner than the vicinity of at least one side. In the illustrated example, the thickness of the portion that becomes the operation surface 21 is thinner than the vicinity of the four sides of the transparent substrate 11. The cover film 14 is stuck on the operation surface 21 of the thinned portion. The cover film 14 is preferably provided on the operation surface 21 so as to have a thickness such that the operation surface 21 is a uniform plane throughout.

  An example of a method for manufacturing the SAW touch panel 1 according to the third modified example described above is as follows. First, a transducer serving as a surface acoustic wave generation unit and a surface acoustic wave detection unit is formed on a transparent substrate having a uniform thickness. Next, of the operation surface opposite to the surface on which the transducer is formed (that is, the propagation surface), a portion corresponding to the actual operable region is etched to thin the portion. And a cover film is stuck on this thinned part.

  According to the present invention, it is possible to realize a SAW touch panel in which the position detection accuracy does not deteriorate even when foreign matter such as water droplets or dust adheres to the operation surface side. In addition, since the surface of the surface acoustic wave propagation faces the contacted member so as to have a predetermined interval, it is difficult for foreign matter to adhere to the propagation surface. Since the SAW touch panel has a smaller number of components and a simple structure compared to other types of touch panels such as a resistive film type, a very thin input / output device can be easily realized.

  Moreover, since the cover film can be attached to the operation surface side as compared with the conventional SAW touch panel, the function can be easily expanded. For example, by sticking a cover film, even if a transparent substrate breaks, it is possible to prevent scattering of broken pieces. The present invention is also optimal as a touch panel for devices that require impact resistance, such as mobile devices such as PDAs, mobile phones, and notebook computers, and in-vehicle devices such as car navigation systems and car audio. For example, when used as a touch panel of a vehicle-mounted device, an anti-glare film or a film having a polarization function may be attached.

  Further, in the present invention, the propagation surface of the transparent substrate bent by the touch operation of the operation surface is due to the contact with the contacted member, that is, the propagation of the surface acoustic wave is always blocked by the contacted member. Touch operation with almost the same input load regardless of whether the material is difficult to absorb or absorbs surface acoustic waves because it is due to contact with the propagation surface Therefore, variations in the feeling of use can be suppressed. For example, the same feeling of use can be obtained when a touch operation is performed with a finger and when a touch operation is performed with a metal pen. In general, the lower the input load, the better the feeling of use. However, if the input load is extremely low, it may cause an erroneous input, so it is desirable to set an appropriate input load.

  Further, according to the present invention, a transparent substrate having flexibility, wherein the surface facing the contacted member located on the opposite side to the operation surface to be touched is a surface acoustic wave propagation surface. As long as it is provided, the SAW touch panel type coordinate input device can be easily realized regardless of the contacted member. If the function as the image output device is not particularly required, the contacted member may be, for example, a simple plate material instead of the display screen of the display device. In this case, the transparent substrate is not necessarily transparent. Since the SAW touch panel according to the present invention is thin and does not deteriorate the position detection accuracy due to foreign matter, it can be applied as a highly versatile touch panel type input device that can be used in various environments.

1 is a top view of a SAW touch panel according to an embodiment of the present invention. It is AA sectional drawing in FIG. 1 of the SAW touchscreen by the Example of this invention. 2 is a cross-sectional view of a transducer in a SAW touch panel according to an embodiment of the present invention. FIG. It is sectional drawing which shows the 1st modification of the SAW touchscreen by the Example of this invention. It is a perspective view which shows the 2nd modification of the SAW touchscreen by the Example of this invention. It is a perspective view which shows the 3rd modification of the SAW touchscreen by the Example of this invention. It is AA sectional drawing which shows the 3rd modification of the SAW touchscreen by the Example of this invention. It is sectional drawing which shows the prior art example of the touchscreen using a surface acoustic wave. It is a top view which shows the prior art example of the touchscreen using a surface acoustic wave. It is a disassembled perspective view which shows the transducer which implement | achieves a surface acoustic wave production | generation means and a surface acoustic wave detection means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 SAW touch panel 11 Transparent substrate 12 Surface acoustic wave production | generation means 13 Surface acoustic wave detection means 14 Cover film 15 Support member 21 Operation surface 22 Propagation surface 31 Sound absorption material 32 Leading wiring 60 Transducer 61 Piezoelectric thin film 62 Short-circuit electrode 63 Comb-shaped electrode 64 Bus electrode

Claims (17)

A transparent substrate having flexibility and a surface facing a contacted member located on the opposite side to the operation surface to be touched, and having a surface acoustic wave propagation surface;
The position of the touch operation is detected based on a change in the propagation state of the surface acoustic wave that occurs when the propagation surface of the transparent substrate that is bent by the touch operation of the operation surface comes into contact with the contacted member. A touch panel characterized by that. Surface acoustic wave generating means for generating the surface acoustic wave so as to propagate on the propagation surface of the transparent substrate;
Surface acoustic wave detection means for detecting the surface acoustic wave generated by the surface acoustic wave generation means;
The touch panel according to claim 1, further comprising:   The touch panel according to claim 1, wherein the contacted member is a display screen.   The touch panel according to claim 1, further comprising a cover film provided on the operation surface of the transparent substrate.   The touch panel according to claim 4, wherein the cover film is made of an antiglare-treated member.   The touch panel according to claim 4, wherein the cover film is made of a polarizing member. Of the four sides on the transparent substrate having a substantially quadrangular propagation surface, the surface acoustic wave generating means is provided on the two opposite sides and the surface acoustic wave detecting means is provided on the remaining two sides.
The touch panel as set forth in claim 2, wherein the surface acoustic wave generating means generates the surface acoustic wave so as to propagate in a direction substantially parallel to a diagonal line of the propagation surface.   The touch panel as set forth in claim 7, further comprising a sound absorbing material provided on the propagation surface of the transparent substrate on a side opposite to a side where the surface acoustic wave generation unit and the surface acoustic wave detection unit face each other.   The touch panel as set forth in claim 7, wherein each of the surface acoustic wave generation means and the surface acoustic wave detection means comprises a transducer having a structure in which a piezoelectric thin film is sandwiched between a short-circuit electrode and an array of unipolar comb electrodes.   The touch panel as set forth in claim 9, further comprising a sound absorbing material made of an insulator provided so as to cover at least a part of the bus electrode and the routing wiring provided on the opposite side to the side on which the transducers face each other.   The touch panel according to claim 8 or 10, wherein the transparent substrate is supported on the contacted member by the sound absorbing material.   The touch panel according to claim 1, further comprising support members that support the transparent substrate on the contacted member at four corners of the propagation surface having a substantially quadrangular shape.   The transparent substrate having a substantially quadrangular propagation surface has a structure in which the thickness of the portion serving as the operation surface is made thinner than at least one side of the transparent substrate while maintaining the propagation surface in a uniform plane. The touch panel according to claim 1.   The touch panel as set forth in claim 13, wherein a thickness of a portion to be the operation surface is formed to be thinner than at least one side of the transparent substrate by an etching process.   A cover film provided on the operation surface of the thinned portion, further comprising a cover film having a thickness such that the operation surface becomes a uniform flat surface as a whole by being provided on the operation surface. 13. The touch panel according to 13.   The surface acoustic wave having a surface facing a contacted member located on the opposite side of the operation surface of the transparent substrate having flexibility as a propagation surface, and the operation surface of the transparent substrate is bent by the touch operation. A touch panel type coordinate input method, wherein the position of the touch operation is detected based on a change in a propagation state that occurs when a propagation surface comes into contact with the contacted member.   The touch-panel type coordinate input method according to claim 16, wherein the contacted member is a display screen.

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