JP2007511015A - Sonic touch detector - Google Patents

Abstract

Two groups of inclined lines (16, 20) included in the spurious wave scattering means are formed in the vicinity of the upper edge of the substrate (2) at opposite angles with respect to each other. The angles of these tilt lines are adapted to approach perpendicular to the central portion of the substrate and gradually decrease toward their edges. The other two groups of tilt lines (26, 30), also included in the spurious wave scattering means, are formed in a similar manner with progressively changing angles at opposite angles with respect to each other. The spurious waves that reach these regions are scattered by the tilt lines so that they are not transmitted to the converters (sensors) (12, 14). Further, three rectangular spurious wave scattering means (34, 36, 38) formed by inclined lines inclined at an angle other than 45 ° also function to diffuse and remove spurious waves propagating along the surface of the substrate. To do.

Description

  The present invention relates to a sonic contact detection device such as an ultrasonic touch panel.

  Ultrasonic contact detection devices are widely used. Examples of such applications include personal computer operation screens, railway station ticket machines, copy machines installed in convenience stores, ATMs in financial facilities, and the like. These sonic contact detection apparatuses use a transducer including a piezoelectric vibrator (piezoelectric element) provided on a substrate (touch panel) formed of glass or the like. These transducers function both as a generator for bulk waves and as a sensor for detecting sound waves scattered by a finger or the like that contacts the touch panel. The surface acoustic wave is scattered by a finger or the like. Scattering of the surface acoustic wave is detected by the detection means. The detected signal is collated with the clock signal of the controller to determine the position where the surface acoustic wave is scattered.

  The ultrasonic vibration is generated as a bulk wave, converted into a surface acoustic wave by the sound wave generating means, and transmitted along the substrate.

  When bulk waves are converted to surface acoustic waves by the sound wave generating means, not all bulk waves are converted. Spurious waves are generated including bulk waves that have not been converted, surface acoustic waves that have passed through the reflective array, and surface acoustic waves that have been reflected in directions other than a predetermined direction. When these spurious waves are reflected along the substrate and reach the sensor-side converter, they vibrate these converters and generate a voltage. These voltages are received as noise and upset the proper judgment by the controller.

  For this reason, the substrate is provided with a vibration blocking or vibration absorbing material that absorbs the generated spurious waves (for example, Patent Document 1 (second page, FIG. 1) and Patent Document 2 (page 11, 2). These vibration isolating and vibration absorbing materials are usually in the form of resin tape and are attached to the substrate by adhesion. The spurious wave that reaches the tape is absorbed and attenuated.

In the prior art, it is necessary to attach the vibration isolating or vibration absorbing member to the substrate. This is done manually by gluing, thus increasing the manufacturing process and reducing productivity. As a result, there is a problem that the manufacturing cost increases.
JP-A-6-324792 JP-A 61-239322

  The present invention was developed from the above viewpoint. An object of the present invention is to provide a sonic contact detection device that efficiently scatters and removes spurious waves, improves productivity, and reduces manufacturing costs.

The sonic contact detection device of the present invention includes:
A substrate having a surface along which sound waves propagate;
Sound wave generating means;
A reflective array for propagating the generated sound waves along the surface of the substrate;
A detector for detecting changes in the acoustic wave caused by an object in contact with the surface of the substrate; and
Controller for determining the geometric coordinates of the object;
With
Spurious wave scattering means for diffusing spurious waves generated accompanying the generation of sound waves is formed on the substrate.

  A configuration in which the spurious wave scattering means includes a reflective array formed of the same material as the substrate is employed.

  The sound wave generating means and the spurious wave scattering means can be formed by either printing or etching.

  In this case, the “sound wave” includes, in addition to the surface sound wave propagating on the surface of the substrate, an ultrasonic wave propagating along the surface in the thin substrate.

  The sound wave generating means can include a mode conversion element and an ultrasonic transducer.

  The detector can be a converter. This converter is an element that converts ultrasonic vibration into an electric signal or an element that converts electric signal into ultrasonic vibration.

  The spurious wave scattering means can be a diffusion grating.

  In the sonic contact detection device of the present invention, spurious wave scattering means for diffusing spurious waves generated accompanying the generation of sound waves is formed on the substrate. Therefore, the spurious wave can be effectively scattered by the spurious wave scattering means.

  A configuration in which the spurious wave scattering means includes a reflective array formed of the same material as the substrate can be employed. In that case, spurious waves can be effectively scattered.

  The sound wave generating means and the spurious wave scattering means can be formed by printing. In that case, in addition to enabling efficient spurious wave scattering, the automated printing enables efficient manufacturing, thereby improving productivity and lowering manufacturing costs. Instead, the sound wave generating means and the spurious wave scattering means may be formed by etching. Even in that case, in addition to enabling efficient spurious wave scattering, a single method can be used for both means, increasing productivity and lowering manufacturing costs. .

  A preferred embodiment of a sonic contact detection device (hereinafter simply referred to as “device”) will be described below with reference to the accompanying drawings.

  FIG. 1 is a front view of a touch panel 3 to be used in the device 1. As shown in FIG. 1, the touch panel 3 includes a substrate 2 formed by a rectangular glass plate; a flexible printed circuit 4 (FPC) mounted on the substrate 2; It includes a linked controller 6.

  The FPC 4 is branched into an FPC branch 4a and an FPC branch 4b. The FPC branch 4a extends along the horizontal direction of the substrate 2, that is, the X-axis direction indicated by the arrow X. The FPC branch 4b extends along the vertical direction orthogonal to the X axis of the substrate, that is, the Y axis direction indicated by the arrow Y. Converters (bulk wave generating means) 8 and 10 for generating ultrasonic waves are mounted on the FPC 4. In addition, converters (detectors) 12 and 14 functioning as sensors are mounted on the FPC 4.

  On the front surface of the substrate 2, a reflection array 18 including a large number of inclined lines 16 is formed in the vicinity of the side edge 44 along the Y axis. On the other side edge 44 of the substrate, a reflective array 22 including a large number of inclined lines 20 is formed so as to face the reflective array 18. In the vicinity of the upper edge 24 of the substrate 2, a reflection array 28 including a large number of inclined lines 26 is formed along the X axis. In the vicinity of the lower edge 45 of the substrate, a reflection array 32 including a large number of inclined lines 30 is formed to face the reflection array 28. The patterns of these reflective arrays 18, 22, 28, and 32 are those disclosed in Patent Document 2 and Japanese Patent Application Laid-Open No. 2001-14094. It should be noted here that the reflective arrays 18, 22, 28, and 32 are collectively referred to as the reflective array 33. The reflective array 33 reflects sound waves and propagates them along the front surface of the substrate 2.

  Converters 8, 10, 12, and 14 are attached to the back surface of substrate 2 by adhesion. On the front surface of the substrate 2, mode conversion elements 78, 80, 82, and 84 (lattice) are formed at positions corresponding to the converters 8, 10, 12, and 14, respectively. This configuration will be described with reference to FIG. 11 by taking the mode conversion element 80 as an example. FIG. 11 is a partially enlarged cross-sectional view of the substrate 2 as viewed from the direction of the arrow A. The mode conversion element 80 of FIG. 11 is formed by sintering glass paste on the substrate 2 and includes a plurality of parallel ridges 80a. The ridge 80a shown in FIG. 11 extends in a direction perpendicular to the drawing paper surface of this figure.

  The width of the ridge 80a is set to be 400 μm, and the height thereof is set to be 35 μm or more. The direction in which the bulk waves are reflected is changed by changing the spacing between the ridges 80a. In this embodiment, ridges 80a are formed at intervals that generate surface acoustic waves immediately adjacent to ridges 80a. The converter 10 is attached by adhesion on the substrate opposite to the mode conversion element 80, and is electrically connected to the FPC branch 4b by soldering.

  The remaining mode conversion elements 78, 82, and 84 have the same configuration. Among them, a mode conversion element (sound wave generating means) indicated by reference numerals 78 and 80 converts bulk waves generated by the transmission side converters 8 and 10 into surface sound waves. The mode conversion elements 82 and 84 convert surface acoustic waves (sound waves) propagating along the front surface of the substrate 2 into bulk waves.

  The converter 10 generates ultrasonic vibration (bulk wave) at a frequency of about 5.5 MHz. The ultrasonic vibration moves from the back surface of the substrate 2 through the inside thereof and reaches the mode conversion element 80. The mode conversion element 80 converts ultrasonic vibrations into surface acoustic waves, which are transmitted (reflected) toward the reflective array 32 perpendicular to the ridge 80a. The surface acoustic wave is reflected by the inclined line 30 inclined inward of the reflective array 32, propagates toward the reflective array 28, and reaches the inclined line 26 inclined inward along the front surface of the substrate 2.

  Bulk waves that have not been converted to surface acoustic waves by the mode conversion elements 78 and 80 are not radiated in a specific direction and propagate from the mode conversion elements 78 and 80 in all directions. If some of the unconverted bulk waves are transmitted towards the converters 12 and 14, they become spurious waves that interfere with the detection of the main signal. In addition, even if the mode conversion elements 78 and 80 are configured to generate surface acoustic waves in a direction perpendicular to their ridges, a slight surface acoustic wave can be generated in an unintended direction. Are known. These surface acoustic waves can also be spurious waves that interfere with the detection of the main signal. When these spurious waves reach converters 12 and 14, a noise signal is generated there.

  The surface acoustic wave that has reached the reflection array 28 is reflected and propagates toward the mode conversion element 84. The surface acoustic wave that reaches the mode conversion element 84 is thereby converted into a bulk wave. The converted bulk wave is transmitted to the converter 14 on the back surface of the substrate 2, which detects its vibration and converts it into an electrical signal.

  The ultrasonic vibration (bulk wave) generated by the converter 8 is also converted into a surface acoustic wave by the mode conversion element 78 in a similar manner. Thereafter, these surface acoustic waves reach the mode conversion element 82 via the reflective array 18 and the reflective array 22. These surface acoustic waves are converted into bulk waves by the mode conversion element 82 and transmitted to the converter 14 where they are detected and converted into electrical signals.

  In this way, surface acoustic waves propagate over all areas covered by the reflective arrays 18, 22, 28 and 32 on the front surface of the substrate 2. Therefore, when a finger (object) contacts (touches) the substrate 2 in this region, the surface acoustic wave is blocked by the finger and disappears or attenuates. Signal changes accompanying changes in the surface acoustic wave are transmitted from the converters 12 and 14 functioning as sensors to a timing circuit (not shown) of the controller 6 connected thereto. The controller 6 determines the geometric coordinates of the position touched by the finger.

  The surface acoustic wave is reflected by each of the inclined lines 16, 20, 26, and 30 of the reflection array 33. 0.5% to 1% of the surface acoustic wave reaching each tilt line is thereby reflected. The rest passes through and is transmitted to adjacent tilt lines, so that all tilt lines continuously reflect surface acoustic waves.

  Spurious wave scattering means for reducing noise by diffusion of spurious waves, that is, a diffusion grating (diffusion part) is formed on the front surface of the substrate 2 of the apparatus 1. The diffusion grating is along the rectangular portion indicated by reference numerals 34, 36 and 38 in FIG. 1, the diffusion grating 43 formed by the inclined lines 40 and 42 along the upper edge 24, and the side edges 44. A diffusion grating 49 formed by inclined lines 46 and 48 is included. The inclined lines 40, 42, 46, and 48 constitute a second reflective array that has a different function than the reflective arrays 18, 22, 28, and 32. A second reflective array is also provided in the diffusion gratings 34, 36, and 38 (see FIG. 7). Details of the diffusion gratings 34, 36, 38, 43, and 49 will be described later. It should be noted here that these diffusion gratings are collectively called a diffusion grating 50.

  Next, the FPC 4 attached to the substrate 2 by bonding will be described with reference to FIG. 2, FIG. 3, and FIG. FIG. 2 is a front view illustrating the FPC 4 attached to the substrate 2. The FPC 4 is attached to the back surface of the substrate 2 by adhesion, but for convenience, it is drawn using a solid line. It should be noted here that the reflection array 33 and the diffusion grating 50 are omitted in FIG. FIG. 3 is a schematic plan view showing the entire FPC 4. FIG. 4 is an enlarged view of the portion of FPC 4 indicated by B in FIG. These FPCs 4 shown in FIGS. 3 and 4 correspond to the state seen from the back surface of the substrate 2 in FIG.

  Electrodes 52 and 54 correspond to converters (sensors) 12 and 14, respectively, and are provided at one end of the FPC 4 as shown in FIGS. The electrodes 52 and 54 are connected to the converters 12 and 14 from above by soldering, a conductive adhesive such as silver paste, or an anisotropic conductive adhesive. In other words, converters 12 and 14 are arranged between FPC 4 and the back surface of substrate 2. The FPC 4 is constituted by the FPC branches 4 a and 4 b described above and the connection line 4 c for connecting to the controller 6.

  The connection line 4c and the FPC branch 4a have the same length and are integrally formed as a band (see FIG. 3). A perforation 56 is formed between the connection line 4c and the FPC branch 4a to allow separation between the two. An electrode 58 for connecting to the converter 8 is provided at the end of the FPC branch 4 a opposite to the end provided with the electrode 52. An electrode 60 for connecting to the controller 6 is provided at the end of the connection line 4 c close to the electrode 58. An electrode 62 for connecting to the converter 10 is provided at the end of the FPC branch 4b opposite to the end provided with the electrode 54 (see FIG. 3).

  As shown in FIG. 4, the printed wiring 64 of the connection line 4c includes ten printed lines, namely 64a, 64b, 64c, 64d, 64e, 64f, 64g, 64h, 64i, and 64j. The signal line group is constituted by four printed lines (signal receiving lines) 64d, 64e, 64f, and 64g connected to the converters (sensors) 12 and 14. What is important here is that ground lines 64c and 64h are provided on either side of the signal line group.

  Signal lines 64b and 64i connected to transmission converters 8 and 10 are provided adjacent to ground lines 64c and 64h, respectively. Further, ground lines 64a and 64j are provided adjacent to the signal lines 64b and 64i, respectively, on the outside thereof. This configuration results in signal receiving lines 64d, 64e, 64f, and 64g being surrounded by ground lines 64c and 64h and signal transmitting lines 64b and 64i being surrounded by ground lines 64c and 64a and 64h and 64j, respectively. Shielding of all signal lines is provided. This relationship is similarly maintained in the FPC branch 4a and the FPC branch 4b. With this configuration, the signal line group including the printed lines 64b, 64d, 64e, 64f, 64g, and 64i is not easily affected by external electromagnetic waves. At the same time, an effect of making it difficult for electromagnetic waves to be emitted toward the outside can be obtained. The above configuration is particularly effective in improving the EMI prevention characteristics when the FPC 4 is extended over a long distance along the substrate 2.

  Note that the bend line of the FPC branch 4b is indicated by reference numerals 66 and 68 in FIG. The FPC branch 4b is bent along the bending line 66 in a direction toward the surface of the drawing paper surface of FIG. Thereafter, the FPC branch 4b is bent along the bending line 68 in a direction away from the surface of the drawing paper surface of FIG. 4, and as a result, the electrode 62 (see FIG. 3) faces the converter 10. In FIG. 2, the bent portion is indicated by reference numeral 69. In this way, the FPC branch 4 b is arranged along the side edge 44 of the substrate 2. It should be noted here that the FPC 4 is fixed to the substrate 2 by an adhesive (not shown) or the like.

  Next, the configuration of the reflective array 33 will be described with reference to FIG. FIG. 5 is a front view of the reflective array 33 corresponding to that shown in FIG. In FIG. 5, the diffusion gratings 34, 36, 38 for scattering spurious waves, and others are omitted. The inclined lines 16, 20, 26, and 30 of the reflective arrays 18, 22, 28, and 32 are each inclined at an angle of 45 °. The inclined lines 16, 20, 26, and 30 are configured to reflect surface acoustic waves toward a reflective array that they face across the substrate 2. The reflective array 33 is formed by printing fine particles of lead glass formed in a paste on the front surface of the substrate 2 by screen printing or the like and then sintering at about 500 ° C. It should be noted here that in FIG. 5, the corner of the substrate 2 is partially illustrated and is indicated by reference numeral 25. Instead of the above, a UV effect ink or an organic ink in which metal particles are added as a filler to improve the reflection characteristics may be used as the material of the reflection array.

  The spacing between the tilt lines 16, 20, 26, and 30 is gradually reduced, in other words, the tilt lines are configured such that the density of the tilt lines increases with distance from the transmitting converters 8 and 10. This is because the intensity of the surface acoustic wave is attenuated as it passes through the inclined lines 16, 20, 26 and 30. Therefore, it is necessary to employ the above-described configuration to compensate for this attenuation and to propagate the surface acoustic wave uniformly along the front surface of the substrate 2. Note that the reflective arrays 22 and 28 are provided slightly inward from the top edge 24 and side edges 44 (see FIG. 1) of the substrate, respectively. This is so that inclined lines 40, 42, 46, and 48 of the diffusion grating 50 described below are provided outside the reflective arrays 22 and 28.

  Next, the diffusion grating 50 functioning as spurious wave scattering means will be described with reference to FIG. FIG. 6 is a front view corresponding to FIG. 1 and shows the diffusion grating 50 with mode conversion elements 78, 80, 82, and 84. The inclined lines 40 and 42 constituting the second reflective array are formed at angles opposite to each other in the vicinity of the upper edge 24 of the substrate 2. The angles of these tilt lines approach perpendicular to the stop portion of the substrate 2 and gradually decrease toward their ends. The inclined lines 46 and 48 that make up the other second reflective array are also formed with progressively changing angles at angles that are opposite to each other in a similar manner. This is for spurious waves to be diffused without being reflected in the same direction.

  Inclined lines 40, 42, 46, and 48 are positioned in the area where the tape or the like is bonded in a conventional touch panel. In other words, the inclined lines 40, 42, 46, and 48 are formed to replace the conventional touch panel tape. Spurious waves reaching these areas are diffusely reflected by the inclined lines 40, 42, 46 and 48 so that they are not transmitted to the converters (sensors) 12 and 14. The attenuation rate of ultrasonic vibration energy varies depending on the ultrasonic frequency, vibration mode, and glass type. The intensity of the 5.5 MHz surface acoustic wave is attenuated to 1/10 of the original intensity after 40 cm of propagation along a typical substrate 2 made of soda lime glass. Thus, the diffusely attenuated spurious waves are rapidly attenuated and disappear when they are reflected across the substrate 2.

  A plurality of independent ridges, ie inclined lines inclined at an angle other than 45 ° or −45 °, are formed in the rectangular diffusion gratings 34, 36, and 38. The shape of these ridges will be described with reference to FIGS. FIG. 7 is a partially enlarged view of the diffusion grating 36 and the reflection array 33. FIG. 8 is a partially enlarged view of the diffusion grating 38 and the reflection array 33. FIG. 7 clearly shows that the tilted line 36a of the diffusing grating 36 is oriented at a different angle than the reflective arrays 18 and 32. FIG. Similarly, FIG. 8 clearly shows the diffusion grating 38 constituted by a more inclined slope line 38a.

  The diffusion gratings 36 and 38 function to diffusely reflect spurious waves propagating along the front surface of the substrate 2 toward the outside at an angle other than 45 ° or −45 °. Although details are not illustrated, the diffusion grating 34 also has a similar structure and function. The inclined lines 36a and 38a can have parallel or progressively changing angles within the respective diffusion grating 36 and diffusion grating 38. Further, the diffusion grating 34 and the diffusion grating 38 block the path of the surface acoustic wave propagating in a direction other than the predetermined direction, so that they do not reach the converters (sensors) 12 and 14.

  The diffusion grating 50 is printed on the substrate 2 in the same manner as the reflective array 33 by the fine particles of lead glass formed in the paste. Therefore, the diffusion grating 50 can be printed simultaneously with the formation of the reflective array 33. This increases productivity and lowers manufacturing costs.

  The inclined lines 36a and 38a of the diffusion gratings 36 and 38 are formed as a plurality of ridges. However, the diffusion grating is not limited to being formed by ridges, and various modifications are possible. An alternative configuration of the diffusion grating (diffusion part) is shown in FIG. FIG. 9 is an enlarged view showing an alternative form of the diffusion grating (diffusion part). The diffusion portion 51 is constituted by a large number of protrusions 51a having a diamond shape in a plan view. Spurious waves that reach the diffused portion 51 are attenuated while being repeatedly reflected in the region formed by the projections 51a in the region. The shape of the protrusion is not limited to a rhombus, and may be any desired shape such as a rectangle, a triangle, another polygon, or an ellipse.

  FIG. 10 is a front view illustrating the relative positions of the diffusion grating 50 and the reflection array 33 formed on the front surface of the substrate 2. FIG. 10 clearly illustrates that the inclined lines 40 and 42 are positioned outside the reflective array 28 and the inclined lines 46 and 48 are positioned outside the reflective array 22. The diffusion gratings 34, 36, and 38 are positioned so that sound waves (surface sound waves) that have passed through the reflection array 33 without being reflected are reflected in a direction different from the direction in which the reflection array 33 reflects them. .

  More specifically, for example, surface acoustic waves generated by converter 8 and mode conversion element 78 are reflected by them toward reflection array 22 while passing through reflection array 18. The surface acoustic wave that has not been reflected by the reflection array 18 reaches the diffusion grating 36. As shown in FIG. 7, the diffusion grating 36 reflects the surface acoustic wave toward the outside of the substrate 2. In other words, the diffusion grating 36 reflects surface acoustic waves in a direction opposite to the main direction, and as a result, ultrasonic vibration that generates noise does not reach the converter (sensor) 12.

  Inclined lines 40, 42, 46 and 48 formed along the edge of the substrate 2 diffusely reflect and attenuate bulk waves propagating along the front surface of the substrate 2. Normally, bulk waves are converted to surface acoustic waves by mode conversion elements 78 and 80. However, the converted bulk wave is not 100% and propagates in a direction different from the predetermined direction. Thus, the tilt lines 40, 42, 46, and 48 are used to attenuate those spurious bulk waves.

  In addition, after the conversion by the mode conversion elements 78 and 80, the surface acoustic wave propagates in a direction different from the predetermined direction. The inclined lines 40, 42, 46, and 48 also provide a diffuse reflection of their stray surface acoustic waves so that they are scattered in various directions. The risk of spurious ultrasonic vibrations reaching the converters (sensors) 12 and 14 and creating noise is reduced by this diffusive reflection.

  A dolphin pattern 82 is printed between the inclined lines 40 and 42 and between the inclined lines 46 and 48 in FIG. The pattern 82 is also effective in reducing noise. These patterns 82 have a curved outline. Bulk waves or stray surface acoustic waves that reach the contour of the picture 82 are reflected and attenuated in various directions. As long as the outline is formed from a curved line or has an angle that diffusely reflects spurious waves in various directions, an arbitrary pattern can be adopted. Alternatively, a pattern may be printed on these portions of the substrate 2.

  The embodiments of the present invention have been described in detail above. However, the invention is not limited to the embodiments described herein. For example, the diffusion grating 50 may be formed by etching using hydrofluoric acid. The diffusion grating 50 can also be formed by a chemical or physical removal process employing laser, sandblasting, or cutting. In other words, the diffusion grating 50 can be formed by grooves instead of protrusions.

  In this embodiment, a case where so-called “grid type” surface acoustic wave generating means having mode conversion elements 78, 80, 82 and 84 is employed is described. However, the present invention is not limited to an apparatus that employs this type of surface acoustic wave generating means. For example, the present invention can be applied to a sonic contact detection device that generates surface acoustic waves by a wedge-type converter (not shown) using an acrylic prism (not shown). The present invention can also be applied to a sonic contact detection device that employs a pair of comb-shaped electrodes formed on an ultrasonic transducer without a lattice or wedge.

  The FPC 4 used in the present invention can be adhered and attached to the substrate 2 using any desired adhesive. However, the piezoelectric vibrator is preferably attached and attached using an ultraviolet curable adhesive. This allows adjustment of the position of the converters 8, 10, 12, and 14 with respect to the mode conversion elements 78, 80, 82, and 84 prior to irradiation with ultraviolet light that provides adhesion to ensure optimal generation of surface acoustic waves. Because.

  The spurious wave scattering means may be of the type that produces diffusive reflection and attenuation, as described herein. It should be noted here that in the embodiment described above, two converters (sensors) 12 and 14 are provided in close proximity to each other. However, these converters (sensors) 12 and 14 may exchange places with the transmitting converters 8 and 10, so that their positions are separated from each other. In this case, when the surface acoustic wave leaks from either the converter 12 or 14, the other converter 14 or 12 is not close to them, so that noise picked up by the other converter is suppressed. In addition, the electrical path from the controller 6 to the transmit converters 8 and 10 is shortened. Accordingly, spurious radiation, that is, radiation of electromagnetic waves from the electrical path can be suppressed.

  Next, another embodiment of the spurious wave scattering means for attenuating and removing spurious waves in the same manner as described above will be described. It should be noted that, in the following description, a case in which spurious wave scattering means is formed by printing glass particles formed in a paste at the same time as the reflection array will be described. However, chemical or physical removal processing for forming grooves such as etching using hydrofluoric acid, laser, sand blasting, or a process employing cutting may be employed.

  FIG. 12 is a front view of a substrate on which spurious wave scattering means of the second embodiment for randomly scattering and removing spurious waves is formed. FIG. 13 is a partially enlarged view of a region where spurious wave scattering means is formed on the substrate of FIG. FIG. 14 is a front view of a substrate with a third embodiment of spurious wave scattering means. FIG. 15 is a front view of a substrate on which spurious wave scattering means of a fourth embodiment similar to FIG. 14 is formed. 12, 13, 14, and 15 exemplify a variation of the (touch panel) device shown in FIG. 1, with diffusion gratings 34, 36, and 38 being second, Note that it is replaced by the spurious wave scattering means of the third and fourth embodiments. Other structures are common throughout these three embodiments, so the same structures are indicated by the same reference numerals and will not be described. In addition, it should be noted that only important portions are illustrated in FIGS. 12 to 15 and other portions are omitted.

1. Removal of Spurious Waves by Random Scattering As an example, a case will be described in which fine protrusions are randomly distributed on the substrate (by the above-described printing method) to form spurious wave scattering means. It should be noted here that, as described above, the concave portions may be formed by chemical or physical grooving (holling) instead of these fine protrusions.

  As shown in FIGS. 12 and 13, diffusion portions 100 and 102 are formed on the side edge 44, the lower edge 45, and the corners of the substrate 2a as spurious wave scattering means. The diffusion portion 100 is rectangular in shape and extends along the side edge 44 and the lower edge 45. The diffusion portion 102 is formed in an L shape at the corner. These diffusing portions 100, 100 and 102 are all located outside the reflective arrays 106 and 108. A large number of diffusion protrusions 104 are randomly arranged in the diffusion portions 100, 100, and 102, that is, without regularity. The shape of the diffusion protrusion 104 is rectangular in the plan view. However, the diffusion protrusion 104 is not limited to a rectangular shape, and may have any desired shape such as a circle, an ellipse, or a polygon. The diffusion protrusions 104 may have the same size, or each diffusion protrusion 104 may have a different size and shape. Here, the distribution of the diffusion protrusions 104 is set so that spurious waves (for example, parasitic echoes) are sufficiently scattered and removed (as a result, they are not detected as noise by the sensor).

  The manner in which the diffusing portions 100, 100, and 102, which are a group of diffusing protrusions 104, scatter and remove spurious waves propagating along the surface of the substrate 2a is the same as that in the above-described embodiment. Therefore, the description is omitted for details. FIG. 12 shows paths 130, 132, 134, 136 that travel until the spurious waves are removed.

2. Removal of spurious waves by coherent scattering In a method in which spurious wave scattering means and a reflective array are simultaneously formed on a substrate by printing paste-like glass particles, the spurious wave scattering means and the inclined line ridge of the reflective array are formed. The heights need to be substantially matched (for example at a height of 5 μm to 10 μm). Furthermore, attenuation and removal of spurious waves in a limited area is desired. In this case, attenuation and removal of spurious waves can be performed more effectively by forming a diffusion grating that creates a coherent scattering effect.

  The frequency and wavelength of spurious waves radiated from the converter and propagating through the substrate are known and are 5.5 MHz and about 570 μm, respectively (for soda glass substrates). Take advantage of these facts.

  As shown in FIG. 14, the diffusion gratings 110a and 110b are formed along the side edge 44 of the substrate 2b. The diffusion gratings 110c and 110d are formed along the lower edge 45 of the substrate 2b. It should be noted here that the diffusion gratings 110a, 110b, 110c, and 110d are collectively referred to as the diffusion grating 110. The diffusion grating 110 is provided in the vicinity of the edge of the substrate 2 b opposite to the mode conversion elements 78, 80, 82, and 84. The diffusion grating 110 includes an outwardly inclined inclined line 112 similar to the diffusion gratings 43 and 49. The inclined lines 112 are provided in parallel with each other, and their inclination angles are smaller than the inclination angles of the diffusion gratings 43 and 49. Due to the configuration of the inclined line 112, the diffusion grating 110 functions to scatter and remove spurious waves by coherent scattering of Rayleigh waves (surface acoustic waves). In other words, Rayleigh waves are scattered and removed while interfering with each other.

3. Removal of spurious waves by converting Rayleigh waves into bulk waves by coherent scattering The removal of spurious waves by coherent scattering described in the above section 2 is different in the form of Rayleigh waves (surface acoustic waves) that have become spurious waves. Do not convert to Rayleigh wave. However, a method is also effective in which Rayleigh waves (surface acoustic waves) are converted into bulk waves, from which components that vibrate perpendicular to the surface of the substrate are removed.

In other words, the propagation direction of the spurious wave is changed or scattered and converted into a bulk wave that propagates while bouncing between the front surface and the back surface of the substrate. Unlike surface acoustic waves, bulk waves do not move at high speed along a horizontal surface, nor do they travel long distances. Therefore, spurious waves can be attenuated and removed more quickly. The conversion of the surface acoustic wave into the bulk wave is called “merging of the Rayleigh wave with respect to the Lamb mode” in the field of acoustics. As shown in FIG. 15, the diffusion grating 120 (120a, 120a, 120b, 120c, and 120d) are similar to the diffusion grating 110 (see FIG. 14) for removing spurious waves by coherent scattering described in the second section above. However, the intervals between the inclined lines constituting the diffusion grating and the widths of the inclined lines are different from those. In addition, the direction (angle) of the inclined line can be the same as or different from the inclined line 112.

  As described above, various configurations can be applied as spurious wave scattering means for scattering and removing spurious waves.

  It should be noted here that in the embodiments described so far, a flexible printed circuit (FPC) is used as the wiring of the electric circuit mounted on the substrate. However, instead of this, a flexible flat cable (FFC) may be employed as the wiring.

It is a front view of a touch panel to be used in the sonic contact detection device of the present invention. It is the front view which illustrated the flexible printed circuit (FPC) attached to a board | substrate. It is a schematic top view which shows the whole FPC. FIG. 4 is an enlarged view of a portion of the FPC indicated by B in FIG. 3. It is a front view of the reflective array corresponding to what was shown in FIG. It is a front view of the mode conversion element and diffusion grating corresponding to what was shown in FIG. It is the elements on larger scale of a reflective array and a diffusion grating. It is another partial enlarged view of a reflective array and a diffusion grating. It is an enlarged view of the alternative form of a diffusion grating. It is the front view which illustrated the relative position of the diffusion grating and the reflective array. FIG. 2 is a schematic partial enlarged view of the substrate of FIG. 1 viewed from the direction of arrow A. It is a front view of the board | substrate with which the spurious wave scattering means for scattering and removing a spurious wave at random is formed. It is the elements on larger scale of the area | region in which the spurious wave scattering means formed on the board | substrate of FIG. 12 was formed. It is a front view of the board | substrate with another embodiment of a spurious wave scattering means. It is a front view of the board | substrate with which the spurious wave scattering means similar to FIG. 14 was formed.

Explanation of symbols

1 Device 2, 2a, 2b, 3c Substrate 3 Touch panel 4 Flexible printed circuit; FPC
4a, 4b FPC branch 4c Connection line 6 Controller 8, 10 Converter 12, 14 Converter; Converter (sensor)
16, 20, 26, 30, 36a, 38a, 40, 42, 46, 48, 112 Inclined line 18, 22, 28, 32, 33, 106, 108 Reflective array 24 Upper edge 25 Corners 34, 36, 38 Rectangular portion Diffusion grating 43, 49, 50, 110, 110a, 110b, 110c, 110d, 120 diffusion grating 44 side edge 45 lower edge 51, 100, 102 diffusion part 51a protrusion 52, 54, 58, 60, 62 electrode 56 perforation 64; Printed wiring 64a, 64c, 64h, 64j Ground line 64b, 64i Signal line 64d, 64e, 64f, 64g Signal receiving line 66, 68 Bending line 69 Bending portion 78, 80, 84 Mode conversion element 80a Parallel ridge; Ridge 82 Mode conversion Element; Design 104 Diffusion protrusion 130, 32,134,136 route

Claims (10)

A substrate having a surface, through which sound waves propagate along the surface,
Sound wave generating means,
A reflective array for propagating the generated sound waves along the surface of the substrate;
A detector for detecting a change in the sound wave caused by an object in contact with the surface of the substrate; and
A controller for determining geometric coordinates of the object;
With
2. A sonic contact detecting device according to claim 1, wherein spurious wave scattering means for diffusing spurious waves generated accompanying the generation of the sonic wave is formed on the substrate.   2. The acoustic contact detection apparatus according to claim 1, wherein the spurious wave scattering means includes a reflective array formed of the same material as the substrate.   The sonic contact detection apparatus according to claim 1, wherein the sound wave generation unit and the spurious wave scattering unit are formed by printing or etching.   3. The sonic contact detection apparatus according to claim 2, wherein the sound wave generating means and the spurious wave scattering means are formed by printing or etching. A substrate having a surface, through which sound waves propagate along the surface,
Mode conversion element,
A reflective array for propagating the generated sound waves along the surface of the substrate;
A detector for detecting a change in the sound wave caused by an object in contact with the surface of the substrate; and
A controller for determining geometric coordinates of the object;
With
A sonic contact detection device, wherein a diffusing portion for diffusing spurious waves generated accompanying the generation of the sonic wave is formed on the substrate.   6. The sonic contact detection device according to claim 5, wherein the diffusing portion includes a group of diffusing protrusions randomly distributed.   6. The diffusion portion includes a plurality of substantially parallel inclined lines that are densely distributed in the vicinity of an edge of the substrate opposite to an edge provided with the mode conversion element. Sonic contact detection device.   The sonic contact detection device according to claim 5, wherein the diffusing portion includes a reflective array formed of the same material as the substrate.   The sonic contact detection device according to claim 5, wherein the mode conversion element and the diffusion portion are formed by printing or etching.   9. The sonic contact detection device according to claim 8, wherein the mode conversion element and the diffusion portion are formed by printing or etching.

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