JP2013200369A - Vibration sensor for musical instrument, pickup saddle, and string musical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noises of a vibration sensor for a musical instrument.SOLUTION: A vibration sensor for a musical instrument includes a substrate having, on at least a surface layer, a lead absorber layer having a thickness of 1 μm or more, a first electrode film bonded to the lead absorber layer and having a plurality of detection areas separated from each other to correspond to detection objects different from each other, a piezoelectric film composed of PZT and bonded to the first electrode film and the lead absorber layer exposed between the detection areas, and a second electrode film overlapped on the first electrode film and the piezoelectric film and bonded to the piezoelectric film.

Description

  The present invention relates to a vibration sensor for a musical instrument, a pickup saddle, and a stringed musical instrument.

  Conventionally, a pickup saddle including a vibration sensor for converting vibration of a string such as a guitar into an electric signal is known (for example, Patent Document 1). By separating the electrodes for each string as described in Patent Document 1, vibration components other than the strings included in the output of the vibration sensor, that is, noise can be reduced.

JP 2008-304558 A

  However, even if the electrodes are separated for each string as described in Patent Document 1, the region of the piezoelectric film positioned between adjacent electrodes also undergoes polarization according to vibration. And the polarization of the area | region of the piezoelectric film located between adjacent electrodes appears in the output of a vibration sensor. Therefore, the effect of suppressing noise due to the separation of the electrodes for each string is limited.

  The present invention has been made in view of the above problems, and an object thereof is to reduce noise of a vibration sensor for musical instruments.

In order to solve the above-described problems, a vibration sensor for musical instrument according to the present invention includes a substrate including a lead absorption layer having a thickness of 1 μm or more on at least a surface layer and a lead absorption layer coupled to each other so as to correspond to different detection targets. A first electrode film having a plurality of detection regions, a piezoelectric film made of PZT bonded to the lead absorption layer and the first electrode film exposed between the plurality of detection regions, and the first A second electrode film overlapping the electrode film and the piezoelectric film and bonded to the piezoelectric film.
According to the present invention, the lead absorption layer absorbs lead from PZT between a plurality of detection regions, thereby reducing the piezoelectric effect of PZT between the plurality of detection regions. Thereby, since vibration components other than the detection target included in the potential difference between the first electrode film and the second electrode film are reduced, noise of the vibration sensor for musical instruments can be reduced.

  Since the thicker the lead absorbing layer, the more lead can be absorbed from the PZT, the entire substrate may constitute the lead absorbing layer.

  The lead absorbing layer may be zirconia. Zirconia maintains a sufficient strength even after annealing for crystallizing PZT.

FIG. 1A is a cross-sectional view according to one embodiment of the present invention. FIG. 1B is a plan view according to one embodiment of the present invention. FIG. 1C is a perspective view according to one embodiment of the present invention. FIG. 2A is a cross-sectional view according to one embodiment of the present invention. FIG. 2B is a plan view according to one embodiment of the present invention. It is sectional drawing concerning one Example of this invention. It is sectional drawing concerning one Example of this invention. It is sectional drawing concerning one Example of this invention.

  Hereinafter, embodiments of the present invention will be described in order with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the corresponding component in each figure, and the overlapping description is abbreviate | omitted.

1. First Embodiment FIG. 1C shows a guitar 1000 as an embodiment of a stringed instrument according to the present invention. The guitar 1000 includes a pickup saddle 10 with a built-in vibration sensor 1, and converts the vibrations of the strings 81, 82, 83, 84, 85, and 86 into electrical signals and outputs them.

  FIG. 1A shows the structure of the pickup saddle 10. The pickup saddle 10 includes a saddle body 80 that supports strings 81, 82, 83, 84, 85, and 86, and a vibration sensor 1 accommodated in the saddle body 80.

  The vibration sensor 1 is a sensor for detecting vibrations of the strings 81, 82, 83, 84, 85, 86, and is a laminated structure manufactured by applying thin film forming technology such as screen printing technology and semiconductor manufacturing technology. Is the body. Accordingly, the substrate 100, the first electrode film 11, and the piezoelectric film 12 constituting the vibration sensor 1 are integrated by direct bonding without using an adhesive or the like. The external dimensions of the vibration sensor 1 can be arbitrarily set according to the shape of the saddle body 80. For example, the thickness of the vibration sensor 1 for detecting six string vibrations may be 0.1 mm to 3 mm, the width of the vibration sensor 1 may be 1 mm to 8 mm, and the length of the vibration sensor 1 may be about 65 mm to 75 mm.

The substrate 100 is a plate-like member having a thickness of 0.2 mm, for example. The substrate 100 is required to have a property of absorbing lead, durability to withstand loads applied during musical instrument performance, and heat resistance to withstand thermal loads in manufacturing processes such as heat treatment of the piezoelectric film 12. For example, a material that absorbs lead, such as ceramics, glass, and glass ceramics, can be the material of the substrate 100. The material of the substrate 100 is particularly preferably zirconia (ZrO ₂ ), for example, partially stabilized zirconia containing yttria. Since zirconia has high heat resistance, it can sufficiently withstand heat treatment for crystallizing the piezoelectric film 12 made of PZT. Further, when the substrate 100 is formed of zirconia, the toughness of the substrate 100 is increased, so that the durability is enhanced and the vibration sensor 1 can be used in a bent state.

  The first electrode film 11 stacked on the upper surface of the substrate 100 is made of a metal such as platinum (Pt) having a thickness of 2 μm, for example. The first electrode film 11 is directly bonded to the upper surface of the substrate 100. The first electrode film 11 has detection regions 11b, 11c, 11d, 11e, 11f, and 11g that are separated from each other. The detection areas 11b, 11c, 11d, 11e, 11f, and 11g are located at positions corresponding to the strings 81, 82, 83, 84, 85, and 86 that are targets for detecting the respective vibrations. Specifically, the detection region 11b is located closest to the string 81, the detection region 11c is located closest to the string 82, the detection region 11d is located closest to the string 83, and is located closest to the string 84. There is a detection area 11e, a detection area 11f is located closest to the string 85, and a detection area 11g is located closest to the string 86. The substrate 100 is exposed between the detection areas 11b, 11c, 11d, 11e, 11f, and 11g. The detection regions 11b, 11c, 11d, 11e, 11f, and 11g are connected by a linear conducting wire portion 11x. The end portion of the conducting wire portion 11x is connected to the external electrode region 11a. That is, the detection regions 11b, 11c, 11d, 11e, 11f, and 11g are electrically connected to the external electrode region 11a by the conductive wire portion 11x.

  The piezoelectric film 12 superimposed on the upper surface of the first electrode film 11 is made of, for example, PZT (lead zirconate titanate) having a thickness of 35 μm. Since the substrate 100 is exposed from between the detection regions 11b, 11c, 11d, 11e, 11f, and 11g, the piezoelectric film 12 is directly coupled to the substrate 100 between the detection regions 11b, 11c, 11d, 11e, 11f, and 11g. doing. Therefore, in the annealing step for crystallizing the piezoelectric film 12, lead is absorbed from the piezoelectric film 12 to the substrate 100 between the detection regions 11b, 11c, 11d, 11e, 11f, and 11g. Therefore, the substrate 100 contains lead in the regions 100a, 100b, 100c, 100d, 100e, 100f, and 100g between the detection regions 11b, 11c, 11d, 11e, 11f, and 11g. On the other hand, the first electrode film 11 functions as a lead barrier layer. Therefore, the lead content of the piezoelectric film 12 is lower in the region between the detection regions 11b, 11c, 11d, 11e, 11f, and 11g than in the other regions.

  The substrate 100, the first electrode film 11 and the piezoelectric film 12 are covered with the second electrode film 15. The second electrode film 15 is made of nickel-based conductive paint, conductive rubber, or the like. The second electrode film 15 can be formed by a method such as brushing, spraying or dipping. Since the second electrode film 15 overlaps the first electrode film 11 and the piezoelectric film 12, the first electrode film 11, the piezoelectric film 12, and the second electrode film 15 constitute a piezoelectric element. By grounding the second electrode film 15, the S / N of the vibration sensor 1 can be further increased by causing the second electrode film 15 to function as an electromagnetic wave shield.

  The vibration sensor 1 is connected to an external circuit by a coaxial cable 7. The coaxial cable 7 includes a first conducting wire 73, a second conducting wire 71, and an insulating layer 72. The first conductive wire 73 of the coaxial cable 7 is joined to the external electrode region 11 a of the first electrode film 11 by the conductive adhesive 13. The second conducting wire 71 of the coaxial cable 7 is directly joined to the second electrode film 15. In order to insulate the external electrode region 11a, the conductive adhesive 13 and the first conductor 73 from the second electrode film 15, the periphery of the external electrode region 11a of the first electrode film 11 is insulated by an insulating heat shrink tube 14. Covered. The heat-shrinkable tube 14 is also fixed so that the coaxial cable 7 is less likely to come off from the vibration sensor 1. If there is an effect of fixing the cable and the periphery of the sensor, the heat-shrinkable tube 14 is covered with tape or surrounded by an adhesive. May be covered. Thus, the vibration sensor 1 connected to the coaxial cable 7 is accommodated in the recess of the saddle body 80, and the gap of the recess is filled with a filler.

  According to the present embodiment, the lead content of the piezoelectric film 12 is lowered between the detection regions 11b, 11c, 11d, 11e, 11f, and 11g of the first electrode film 11, so that the detection regions 11b, The piezoelectric effect of the piezoelectric film 12 becomes low between 11c, 11d, 11e, 11f, and 11g. Therefore, the component corresponding to the polarization of the piezoelectric film 12 between the detection regions 11b, 11c, 11d, 11e, 11f, and 11g in the output of the vibration sensor 1 is reduced. That is, the sensitivity of the piezoelectric film 12 itself is high immediately above the detection regions 11b, 11c, 11d, 11e, 11f, and 11g, and is low between the detection regions 11b, 11c, 11d, 11e, 11f, and 11g. On the other hand, of the pressure applied to the local region of the piezoelectric film 12, the component accompanying the vibration of the strings 81, 82, 83, 84, 85, 86 is higher in the region closer to the strings 81, 82, 83, 84, 85, 86. Become. That is, when the polarization phenomenon of the piezoelectric film 12 is viewed locally, the region closer to the strings 81, 82, 83, 84, 85, 86 is polarized by the string vibration, and the strings 81, 82, 83, 84 , 85, 86, the region farther away from the string vibration (for example, vibration of the sound board 87 of the guitar 1000) causes polarization. In the vibration sensor 1, the region where the sensitivity of the piezoelectric film 12 is high is arranged close to the strings 81, 82, 83, 84, 85, 86 and is far from the strings 81, 82, 83, 84, 85, 86 of the piezoelectric film 12. Since the sensitivity of the piezoelectric film 12 is lowered in the region, vibrations of the strings 81, 82, 83, 84, 85, 86 can be detected with high S / N.

2. Second Embodiment FIG. 2A shows a cross-sectional structure of a vibration sensor 2 as a second embodiment of the present invention. FIG. 2B shows the internal structure of the vibration sensor 2.
As shown in FIG. 2B, the second electrode film 16 is formed in a region that is the same as the upper surface of the piezoelectric film 12 or narrower than the upper surface of the piezoelectric film 12, and overlaps the first electrode film 11 and the piezoelectric film 12. A conductive wire 75 is joined to the end portion of the second electrode film 16 by the conductive adhesive 13. The second electrode film 16 is made of a metal such as gold (Au) or aluminum (Al). The second electrode film 16 is directly bonded to the upper surface of the piezoelectric film 12.

  The conducting wire portion 11 x of the first electrode film 11 protrudes outside the piezoelectric film 12. A conductive wire 75 having a ground potential is bonded to the external electrode region 11 a of the first electrode film 11 by the conductive adhesive 13. Since the conducting wire portion 11x does not overlap the piezoelectric film 12 and the second electrode film 16, the conducting wire portion 11x itself and the piezoelectric film 12 do not transfer charges. Therefore, the vibration sensor 2 can detect the vibrations of the strings 81, 82, 83, 84, 85, 86 with a higher S / N than the vibration sensor 1 of the first embodiment.

  The insulating film 17 superimposed on the upper surface of the second electrode film 16 covers the entire upper surface excluding the end of the second electrode film 16. The insulating film 17 is made of an insulating material such as polyimide having a thickness of 40 μm, for example. The insulating film 17 is directly bonded to the upper surface of the second electrode film 16.

  The shield film 18 overlaid on the upper surface of the insulating film 17 is made of a conductive material such as aluminum having a thickness of 2 μm, for example. The shield film 18 covers most of the upper surface of the insulating film 17 and is coupled to the shield film connection region 11h of the first electrode film 11 to be grounded. For this reason, the shield film 18 functions as an electromagnetic shield. The shield film 18 is directly coupled to the insulating film 17, the piezoelectric film 12, and the first electrode film 11.

3. Third Embodiment FIG. 3 shows a sectional structure of a vibration sensor 3 as a third embodiment of the present invention. The substrate 99 of the vibration sensor 3 includes a lead absorbing layer 98 on the surface layer. The lead absorption layer 98 may be any material that absorbs lead, such as ceramics, glass, glass ceramics, in addition to zirconia. Portions other than the lead absorbing layer 98 of the substrate 99 can be made of a material that does not absorb lead. In order to effectively reduce the sensitivity of the piezoelectric film 12 between the detection regions 11b, 11c, 11d, 11e, 11f, and 11g, the thickness of the lead absorbing layer 98 must be 1 μm or more, and 10 μm or more. It is preferable to do.

4). Manufacturing Method Next, a manufacturing method of the vibration sensor 2 will be described with reference to FIG.
First, as shown in FIG. 4A, the first electrode film 11 is formed on the surface of the substrate 100. The first electrode film 11 is formed by a thin film forming technique such as a screen printing method or a sputtering method. Hereinafter, when a patterning method is required, a known technique is used as needed.

  Next, as shown in FIG. 4B, the piezoelectric film 12 is formed on the first electrode film 11. The piezoelectric film 12 is formed using a thin film forming technique such as a sol-gel method, a sputtering method, a CVD method, or a screen printing method. Thereafter, an annealing step for crystallizing the piezoelectric film 12 is performed under a temperature condition of about 1200 ° C. In the annealing process, lead is absorbed from the piezoelectric film 12 into the substrate 100. When annealing at 1200 ° C. is performed, lead diffuses into the substrate 100 made of zirconia from the interface with the piezoelectric film 12 to a depth of 10 μm. When the annealing process for crystallizing the piezoelectric film 12 made of PZT is thus performed, the lead absorbing layer takes in lead to a depth of 10 μm from the interface with the piezoelectric film 12. Therefore, it is preferable that the thickness of the lead absorption layer capable of absorbing lead from PZT is 10 μm or more. By forming the piezoelectric film 12 by a screen printing method, the end face of the piezoelectric film 12 can be inclined. When the end face of the piezoelectric film 12 is tilted using the screen printing method, the step coverage of the layer formed using the end face of the piezoelectric film 12 and the upper surface of the first electrode film 11 or the substrate 100 as a base surface is improved, and the adhesion strength is increased. Will increase.

  Next, as shown in FIG. 4C, a second electrode film 16 is formed on the piezoelectric film 12. The second electrode film 16 is formed by a thin film forming technique such as a screen printing method or a sputtering method.

  Next, as shown in FIG. 4D, an insulating film 17 is formed on the second electrode film 16. The insulating film 17 is formed by a thin film forming technique such as a screen printing method, a spin coating method, a laminating method, a CVD method, a sputtering method, a vapor deposition method, or a vapor deposition polymerization method.

  Next, as shown in FIG. 4E, a shield film 18 is formed on the insulating film 17. The shield film 18 is formed by a thin film forming technique such as sputtering, CVD, screen printing, or plating.

  Thereafter, when the substrate 100 is divided by a dicer, the vibration sensor 2 is completed. The manufacturing method of the vibration sensor 2 and the vibration sensor 1 is the same up to the step of forming the piezoelectric film 12. Further, when manufacturing the vibration sensor 3, a step of forming a lead absorption layer on the substrate may be added before the first electrode film 11 is formed on the substrate.

5. Other Embodiments The technical scope of the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

  For example, like the vibration sensor 4 shown in FIG. 5, the conductive film 61, 62 is formed on the surface of the piezoelectric film 12 and the back surface of the substrate 100 of the vibration sensor of the first embodiment and grounded, thereby providing an electromagnetic shielding effect. May be raised.

  For example, the detection region of the first conductive film may be rectangular, circular, or any shape. Further, when forming the first conductive film, an alignment mark may be formed by the first conductive film in order to facilitate alignment between the detection region and the detection target. By exposing such an alignment mark to the outside of the vibration sensor, it is easy to align the detection target such as a string and the detection region of the first conductive film.

  In addition, the present invention can be applied to pick-up saddles used for other stringed instruments such as violins and cellos, and can also be applied to vibration sensors such as wind instruments, percussion instruments, and keyboard instruments. The dimensions of the vibration sensor can be arbitrarily set according to the dimensions of the pickup saddle and the instrument body. Furthermore, according to the number of detection objects, such as a string, and the space | interval at which they are arrange | positioned, the number of the detection areas in a vibration sensor and its space | interval can be set arbitrarily.

DESCRIPTION OF SYMBOLS 1 ... Vibration sensor, 2 ... Vibration sensor, 3 ... Vibration sensor, 4 ... Vibration sensor, 7 ... Coaxial cable, 10 ... Pick-up saddle, 11 ... First electrode film, 11a ... External electrode area | region, 11b, 11c, 11d, 11e , 11f, 11g ... detection region, 11x ... conductive wire part, 12 ... piezoelectric film, 13 ... conductive adhesive, 14 ... heat shrinkable tube, 15 ... second electrode film, 16 ... second electrode film, 17 ... insulating film, DESCRIPTION OF SYMBOLS 18 ... Shield film | membrane, 61 ... Conductive film, 71 ... 2nd conducting wire, 72 ... Insulating layer, 73 ... 1st conducting wire, 75 ... Conducting wire, 80 ... Saddle main body, 81, 82, 83, 84, 85, 86 ... String 87 ... sound board, 98 ... lead absorption layer, 99 ... substrate, 100 ... substrate, 1000 ... guitar

Claims (5)

A substrate including a lead absorbing layer having a thickness of 1 μm or more on at least a surface layer;
A first electrode film having a plurality of detection regions coupled to the lead absorbing layer and corresponding to different detection targets and spaced apart from each other;
A piezoelectric film made of PZT bonded to the lead absorbing layer and the first electrode film exposed between the plurality of detection regions;
A second electrode film overlapping the first electrode film and the piezoelectric film and bonded to the piezoelectric film;
A vibration sensor for musical instruments. All of the substrate constitutes the lead absorbing layer;
The vibration sensor for musical instruments according to claim 1. The lead absorbing layer is made of zirconia,
The vibration sensor for musical instruments according to claim 1 or 2. A saddle supporting a string as the detection target;
The instrument vibration sensor according to any one of claims 1 to 3, which is fixed to the saddle,
Pickup saddle with A string as the detection target;
A pickup saddle according to claim 4;
A stringed instrument.

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