JP6842331B2 - Piezoelectric laminate - Google Patents

Description

The present invention relates to a piezoelectric laminate.

Conventionally, it has been known to use a touch panel film using a piezoelectric material for an image display device having a touch panel function. Such a touch panel film enables not only detection of a position touched on the screen but also detection according to the strength of the touched pressure. Specifically, by lightly touching a predetermined part of the touch panel screen with a finger, recognition of the touched part (selection of a predetermined button, etc.) is executed, and then, by strongly touching that part with a finger, another method is performed. Command (decision, etc.) can be executed.

Patent Document 1 describes a piezoelectric layer containing a polyvinylidene fluoride-tetrafluoroethylene copolymer, a first electrode provided on one surface of the piezoelectric layer, and the other surface of the piezoelectric layer. A touch panel including a second electrode provided above is described. In the touch panel of Patent Document 1, as shown in FIG. 1, a plurality of first electrodes elongated in the X-axis direction and a plurality of second electrodes elongated in the Y-axis direction are formed on one surface of the piezoelectric layer and respectively. It is arranged on the other side.

Japanese Unexamined Patent Publication No. 2010-26938

By the way, in the touch panel of Patent Document 1, a voltage is generated in the piezoelectric layer portion corresponding to the touched portion, and a current flows through the first electrode and the second electrode corresponding to the piezoelectric layer portion, so that the current is measured. By doing so, the touch position is detected.

However, since the piezoelectric layer is composed of one sheet continuous in the plane direction, the voltage is transmitted to the portion other than the touched portion in the piezoelectric layer, and the current flows even in an unexpected portion. That is, the current is measured from electrodes at a plurality of locations or a wide range of locations. As a result, there is a problem that the touch position is erroneously detected.

The present invention is to provide a piezoelectric laminate capable of suppressing erroneous detection of a touch position.

The present invention [1] includes a piezoelectric layer, a first electrode layer arranged on one side in the thickness direction of the piezoelectric layer, and a second electrode layer arranged on the other side in the thickness direction of the piezoelectric layer. The first electrode layer has a plurality of independent first electrode portions, and the piezoelectric layer has a plurality of independent piezoelectric portions corresponding to the plurality of first electrode portions. Contains a laminate.

According to this piezoelectric laminate, a plurality of piezoelectric portions exist independently of the adjacent piezoelectric portions while corresponding to the plurality of first electrode portions. Therefore, the piezoelectric portion that detects the touch (pressing) does not affect the other independent piezoelectric portions, and no voltage is generated other than the piezoelectric portion that detects the touch. Therefore, it is possible to detect only the current generated from the piezoelectric portion that has detected the touch. As a result, erroneous detection of the touch position can be suppressed.

The present invention [2] further includes a base film arranged between the piezoelectric layer and the second electrode layer.

According to this piezoelectric laminate, the mechanical strength is increased because the base film is provided. Therefore, it has excellent durability.

According to the present invention [3], the second electrode layer has a plurality of independent second electrode portions corresponding to the plurality of first electrode portions, according to [1] or [2]. Contains a piezoelectric laminate.

According to this piezoelectric laminate, since the plurality of second electrode portions are provided corresponding to the plurality of first electrode portions, the first electrode portion and the second electrode portion correspond to each of the plurality of piezoelectric portions. The electrode part is arranged. Therefore, since the plurality of piezoelectric portions do not share the second electrode portion, the influence of the circuit formed by one piezoelectric portion on the circuit forming another adjacent piezoelectric portion can be suppressed. As a result, noise reduction can be reduced, and erroneous detection of the touch position can be suppressed more reliably.

In the present invention [4], the first electrode portion coincides with the piezoelectric portion when projected in the thickness direction, or is included in the piezoelectric portion, any one of [1] to [3]. Includes the piezoelectric laminates described in the section.

According to this piezoelectric laminate, when the first electrode portion is projected in the thickness direction, it is included in all of the piezoelectric portions, so that an electric charge is stored in the middle of the thickness direction between the first electrode portion and the second electrode portion. There is no easy-to-use air layer (space). Therefore, in the middle, the generation of unnecessary electric charges other than the piezoelectric layer can be suppressed, so that noise can be suppressed. Therefore, erroneous detection of the touch position can be suppressed more reliably.

The present invention [5] includes the piezoelectric laminate according to any one of [1] to [4], wherein the first electrode layer and the second electrode layer are transparent electrode layers.

According to this piezoelectric laminate, it is possible to suppress the visibility of the first electrode portion and the second electrode portion. Therefore, it can be suitably used for touch panel applications.

The present invention [6] includes the piezoelectric laminate according to any one of [1] to [5], wherein the piezoelectric layer is a resin layer.

According to this piezoelectric laminate, the flexibility and film-forming property of the piezoelectric layer are good, so that the piezoelectric laminate can be easily manufactured by roll-to-roll or the like. Therefore, it is excellent in productivity.

The present invention [7] includes the piezoelectric laminate according to [6], wherein the resin layer contains a fluororesin.

According to this piezoelectric laminate, it is excellent in durability and heat resistance.

The present invention [8] includes the piezoelectric laminate according to [7], wherein the fluororesin is a vinylidene fluoride resin.

According to this piezoelectric laminate, it is excellent in transparency, piezoelectric performance and film forming property. Therefore, it can be suitably used for touch panel applications.

In the present invention [9], the vinylidene fluoride-based resin is polyvinylidene fluoride, or a copolymer of vinylidene fluoride with at least one of trifluoroethylene and chlorotrifluoroethylene. , [8] includes the piezoelectric laminate.

According to this piezoelectric laminate, the haze value of the piezoelectric layer is small and the total light transmittance is high, so that the transparency of the piezoelectric laminate is excellent.

In the present invention [10], the vinylidene fluoride-based resin is a vinylidene fluoride-trifluoroethylene copolymer, and the molar ratio of vinylidene fluoride to trifluoroethylene is 100 as a whole (50 to 85). ): Includes the piezoelectric laminate according to [9], which is (50 to 15).

According to this piezoelectric laminate, the haze value of the piezoelectric layer is small and the total light transmittance is high, so that the transparency of the piezoelectric laminate is excellent.

In the present invention [10], the vinylidene fluoride resin is a vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene copolymer, and the molar ratio of vinylidene fluoride to trifluoroethylene to chlorotrifluoroethylene is high. , The piezoelectric laminate according to [9], which is (63 to 65) :( 27 to 29) :( 6 to 10), with the whole being 100.

According to this piezoelectric laminate, the haze value of the piezoelectric layer is small and the total light transmittance is high, so that the transparency of the piezoelectric laminate is excellent.

According to the piezoelectric laminated body of the present invention, erroneous detection of the touch position can be suppressed.

1A to 1B show an embodiment of the piezoelectric laminate of the present invention, FIG. 1A is a cross-sectional view (AA cross-sectional view of FIG. 1B), and FIG. 1B is a plan view. FIG. 2 shows a schematic configuration diagram of a pressure sensor including the piezoelectric laminate shown in FIG. 3A to 3B show a modification of the piezoelectric laminate of the present invention. FIG. 3A shows a form in which the first electrode portion is included in the piezoelectric portion in a plan view. FIG. 3B shows a configuration in which the piezoelectric portion is included in a planar view. , The form included in the first electrode portion is shown. FIG. 4 shows a modified example of the piezoelectric laminate of the present invention (a form in which the second electrode layer includes only one second electrode portion). FIG. 5 shows a modified example of the piezoelectric laminate of the present invention (a form without a base film). FIG. 6 shows a modified example of the piezoelectric laminate of the present invention (a form in which the second electrode layer includes only one second electrode portion and the piezoelectric laminate does not include a base film).

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1A, the vertical direction of the paper surface is the vertical direction (thickness direction, first direction), the upper side of the paper surface is the upper side (one side in the thickness direction, one side in the first direction), and the lower side of the paper surface is the lower side (thickness direction). The other side, the other side in the first direction). Further, in FIG. 1A, the left-right direction of the paper surface is the left-right direction (the second direction orthogonal to the first direction), the left side of the paper surface is the left side (one side of the second direction), and the right side of the paper surface is the right side (the other side of the second direction). Is. Further, in FIG. 1A, the paper thickness direction is the front-rear direction (the third direction orthogonal to the first direction and the second direction), the front side of the paper surface is the front side (one side of the third direction), and the back side of the paper surface is the rear side (third direction). The other side in three directions). Specifically, it conforms to the direction arrows in each figure.

<One Embodiment>
1A-1B show an embodiment of the piezoelectric laminate of the present invention. The piezoelectric laminate 1 shown in FIGS. 1A to 1B has a base film 2, a piezoelectric layer 3 arranged on the upper side (one side in the thickness direction) of the base film 2, and a second piezoelectric layer arranged on the upper side of the piezoelectric layer 3. It includes one electrode layer 4 and a second electrode layer 5 arranged on the lower side (the other side in the thickness direction) of the base film 2. Specifically, the piezoelectric laminate 1 includes a second electrode layer 5, a base film 2, a piezoelectric layer 3, and a first electrode layer 4 in this order. Preferably, the piezoelectric laminate 1 is composed of only the second electrode layer 5, the base film 2, the piezoelectric layer 3, and the first electrode layer 4. Hereinafter, each layer will be described in detail.

(Base film)
The base film 2 is a base material that secures the mechanical strength of the piezoelectric laminate 1. The base film 2 supports the piezoelectric layer 3, the first electrode layer 4, and the second electrode layer 5.

The base film 2 has a film shape and has the outer shape of the piezoelectric laminate 1 in a plan view. The base film 2 is composed of a single film continuous in the surface direction (front-back direction and left-right direction).

The base film 2 is preferably a transparent polymer film. Examples of the material of the polymer film include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate and polyethylene naphthalate, and (meth) acrylic resins such as polymethacrylate (acrylic resin and / or methacrylic resin), for example. , Polyethylene, polypropylene, cycloolefin polymer (COP) and other olefin resins, such as polycarbonate resin, polyether sulfone resin, polyallylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, polystyrene resin, norbornene resin and the like. Be done. The polymer film can be used alone or in combination of two or more.

From the viewpoint of transparency, heat resistance, mechanical strength and the like, a polyester resin is preferable, and PET is more preferable.

The thickness of the base film 2 is, for example, 2 μm or more, preferably 20 μm or more, and for example, 300 μm or less, from the viewpoints of mechanical strength, scratch resistance, and spotting characteristics when used as a touch panel film. It is preferably 150 μm or less.

If necessary, an adhesive layer or the like may be provided on the upper surface and / or the lower surface of the base film 2.

(Piezoelectric layer)
The piezoelectric layer 3 is a layer for generating a voltage when a pressure is applied to the piezoelectric laminated body 1.

The piezoelectric layer 3 has a film shape and is arranged on the upper side of the base film 2 so as to be in contact with the upper surface of the base film 2. More specifically, the piezoelectric layer 3 is arranged between the base film 2 and the first electrode layer 4 so as to be in contact with the upper surface of the base film 2 and the lower surface of the first electrode layer 4. ..

The piezoelectric layer 3 includes a plurality of piezoelectric portions 6 and a plurality of wiring lower portions 11.

The plurality of piezoelectric portions 6 are independent of each other, and are arranged in a substantially central portion in a plan view so as to be spaced apart from each other in the front-rear direction and the left-right direction. The plurality of piezoelectric portions 6 are arranged so as to correspond to the first electrode portion 7 described later. Specifically, the plurality of piezoelectric portions 6 are arranged so as to have a one-to-one correspondence with the plurality of first electrode portions 7. That is, the number of the piezoelectric portions 6 is the same as the number of the first electrode portions 7, and each piezoelectric portion 6 is arranged below each first electrode portion 7.

Each of the piezoelectric portions 6 has a substantially rectangular shape (square shape) in a plan view, and is formed so as to have the same pattern (shape and size in a plan view). The pattern of the piezoelectric portion 6 is the same as the pattern of the first electrode portion 7. That is, when projected in the thickness direction, the piezoelectric portion 6 coincides with the first electrode portion 7.

The plurality of wiring lower portions 11 are arranged corresponding to the plurality of first wiring portions 12 in order to support the plurality of first wiring portions 12 described later. One end of the wiring lower portion 11 is connected to the end edge of the piezoelectric portion 6, the middle portion is located at the side end portion (left end portion or right end portion) of the base film 2, and the other end is located at the front end edge of the base film 2. It is arranged so that it does. The pattern of the wiring lower portion 11 is the same pattern as that of the first wiring portion 12.

Examples of the material forming the piezoelectric layer 3 include an organic piezoelectric material and an inorganic piezoelectric material. These materials can be used alone or in combination of two or more.

Examples of the organic piezoelectric material include fluororesin, polylactic acid, polyurea, and the like, and from the viewpoint of heat resistance and durability, fluororesin is preferable.

Examples of the fluororesin include vinylidene fluoride-based resins from the viewpoints of transparency, piezoelectric performance, and film-forming property.

The vinylidene fluoride-based resin is a polymer of a monomer containing vinylidene fluoride, specifically, a homopolymer of vinylidene fluoride (polyvinylidene fluoride), or a copolymer of vinylidene fluoride and another monomer. Can be mentioned.

Examples of other monomers include trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, hexafluoropropylene oxide, perfluoropropyl vinyl ether and the like. Other monomers can be used alone or in combination of two or more. Preferably, at least one of trifluoroethylene and chlorotrifluoroethylene is mentioned.

Specific examples of the copolymer include vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, and vinylidene fluoride-hexa. Examples thereof include fluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene oxide copolymer, vinylidene fluoride-perfluoropropyl vinyl ether copolymer, vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene copolymer and the like.

Preferred are polyvinylidene fluoride, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, and more preferably vinylidene fluoride-trifluoroethylene copolymer and vinylidene fluoride. -Trifluoroethylene copolymer can be mentioned. By using these vinylidene fluoride resins, the haze value of the piezoelectric layer 3 can be reduced and the total light transmittance can be increased, so that the transparency of the piezoelectric laminate 1 is excellent.

Specifically, when the vinylidene fluoride resin is a copolymer, the molar ratio of vinylidene fluoride contained is, for example, 40 mol% or more, preferably 50% mol or more, and for example, 95. It is mol% or less, preferably 85 mol% or less.

When the vinylidene fluoride-based resin is a vinylidene fluoride-trifluoroethylene copolymer, the molar ratio of vinylidene fluoride to trifluoroethylene is set to 100 as a whole, for example, (40 to 95) :( 60). ~ 5), preferably (50 to 85) :( 50 to 15).

When the vinylidene fluoride-based resin is a vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene copolymer, the molar ratio of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene is set to 100 as a whole, for example. , (50-80) :( 15-35) :( 1-15), preferably (63-65) :( 27-29) :( 6-10).

Examples of the inorganic piezoelectric material include barium titanate, lead zirconate titanate (PZT), zinc oxide, potassium niobate, bismuth ferrite, and quartz.

Preferably, the piezoelectric layer 3 is a resin layer made of an organic piezoelectric material. By using the piezoelectric layer 3 as a resin layer, the piezoelectric layer 3 can be easily and surely formed on the base film 2 by a coating method using a coating liquid containing an organic piezoelectric material or the like. Become. Further, since the piezoelectric layer 3 is a resin layer, it is excellent in flexibility. Therefore, it becomes easy to manufacture the piezoelectric layer 3 (and thus the piezoelectric laminate 1) by an industrially advantageous method such as roll-to-roll, and the productivity is excellent.

The thickness of the piezoelectric layer 3 is, for example, 0.5 μm or more, preferably 1 μm or more, and for example, 100 μm or less, preferably 20 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less. .. By setting the thickness of the piezoelectric layer 3 in the above range, the optical characteristics (haze value, total light transmittance) and the piezoelectric performance can be improved.

(First electrode layer)
The first electrode layer 4 is a layer for extracting an electric current from the piezoelectric layer 3 in which a voltage is generated.

The first electrode layer 4 is the uppermost layer of the piezoelectric laminate 1 and has a film shape. Specifically, the first electrode layer 4 is arranged on the upper side of the piezoelectric layer 3 so as to be in contact with the upper surface of the piezoelectric layer 3.

The first electrode layer 4 includes a plurality of first electrode portions 7 and a plurality of first wiring portions 12.

The plurality of first electrode portions 7 are independent of each other, and are aligned with each other in the front-rear direction and the left-right direction at a substantially central portion in a plan view. As described above, the plurality of first electrode portions 7 are arranged so as to correspond to the plurality of piezoelectric portions 6. Each of the first electrode portions 7 has a substantially rectangular shape (square shape) in a plan view, and is formed so as to have the same pattern as each other. The pattern of the first electrode portion 7 is the same as the pattern of the piezoelectric portion 6.

One end of the plurality of first wiring portions 12 is connected to the edge of the first electrode portion 7, the middle portion is located at the side end portion (left end portion or right end portion) of the base film 2, and the other end is the base film. It is arranged so as to be located at the front edge of 2.

The material constituting the first electrode layer 4 may be conductive, and examples thereof include metal materials such as copper, silver, gold, and nickel, for example, transparent conductive materials.

From the viewpoint of touch panel applications and the like, a transparent conductive material is preferable. Examples of the transparent conductive material include a conductive inorganic oxide and a conductive polymer.

Examples of the conductive inorganic oxide include indium-containing oxides such as indium-tin composite oxide (ITO), indium zinc composite oxide (IZO), and indium gallium zinc composite oxide (IGZO), for example, antimony tin. Examples thereof include antimony-containing oxides such as composite oxides (ATO).

Examples of the conductive polymer include polyethylene dioxythiophene, polypyrrole, polyaniline and the like.

Preferred are conductive inorganic oxides, more preferably indium-containing oxides, and even more preferably ITO. As a result, the first electrode layer 4 can be used as a transparent electrode layer, and its transparency, conductivity, and durability are excellent.

When ITO is used as the material of the first electrode layer 4, the tin oxide (SnO ₂ ) content is, for example, 0.5% by mass or more with respect to the total amount of tin oxide and indium oxide (In ₂ O _3). It is preferably 3% by mass or more, and for example, 15% by mass or less, preferably 13% by mass or less.

“ITO” may be a composite oxide containing at least indium (In) and tin (Sn), and may contain additional components other than these. Examples of the additional component include metal elements other than In and Sn, and specifically, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W and Fe. , Pb, Ni, Nb, Cr, Ga and the like.

The first electrode layer 4 may be either crystalline or amorphous. The first electrode layer 4 is preferably made of crystalline material, and more specifically, it is a crystalline ITO layer. As a result, the transparency and conductivity of the first electrode layer 4 can be further improved.

The fact that the material of the first electrode layer 4 is crystalline means that, for example, when the first electrode layer 4 is an ITO layer, it is immersed in hydrochloric acid (concentration 5% by mass) at 20 ° C. for 15 minutes, then washed with water and dried. However, it can be determined by measuring the resistance between terminals between about 15 mm. Specifically, when the resistance between terminals for 15 mm is 10 kΩ or less after immersion in hydrochloric acid (20 ° C., concentration: 5% by mass), washing with water, and drying, the ITO layer is assumed to be crystalline.

The thickness of the first electrode layer 4 is, for example, 10 nm or more, preferably 15 nm or more, and for example, 100 nm or less, preferably 50 nm or less.

(Second electrode layer)
The second electrode layer 5 is a layer that is paired with the first electrode layer 4 and is for extracting a current from the piezoelectric layer 3 in which a voltage is generated.

The second electrode layer 5 is the lowest layer of the piezoelectric laminate 1 and has a film shape. Specifically, the second electrode layer 5 is arranged on the lower side of the base film 2 so as to be in contact with the lower surface of the base film 2.

The second electrode layer 5 includes a plurality of second electrode portions 8 and a plurality of second wiring portions 13.

The plurality of second electrode portions 8 are independent of each other, and are aligned and arranged in the front-rear direction and the left-right direction at a distance from each other in the substantially central portion of the bottom surface. The plurality of second electrode portions 8 are arranged so as to correspond to the plurality of piezoelectric portions 6. Specifically, the plurality of second electrode portions 8 are arranged so as to have a one-to-one correspondence with the plurality of piezoelectric portions 6. That is, the number of the plurality of second electrode portions 8 is the same as the number of the piezoelectric portions 6, and each of the second electrode portions 8 is arranged under each piezoelectric portion 6 via the base film 2. There is.

Each of the second electrode portions 8 has a substantially rectangular shape (square shape) in a plan view, and is formed so as to have the same pattern as each other. The pattern of the second electrode portion 8 is the same as the pattern of the piezoelectric portion 6 and the first electrode portion 7. That is, when projected in the thickness direction, the second electrode portion 8 coincides with the piezoelectric portion 6 and the first electrode portion 7.

One end of the plurality of second wiring portions 13 is connected to the edge of the second electrode portion 8, the middle portion is located at the side end portion (left end portion or right end portion) of the base film 2, and the other end is the base film. It is arranged so as to be located at the front edge of 2.

Examples of the material constituting the second electrode layer 5 include the same materials as those of the first electrode layer 4. A transparent conductive material is preferable, a conductive inorganic oxide is more preferable, ITO is more preferable, and crystalline ITO is most preferable. As a result, the second electrode layer 5 can be used as a transparent electrode layer, and its transparency, conductivity, and durability are excellent.

The thickness of the second electrode layer 5 is, for example, 10 nm or more, preferably 15 nm or more, and for example, 100 nm or less, preferably 50 nm or less.

2. Method for manufacturing the piezoelectric laminate 1 The method for manufacturing the piezoelectric laminate 1 includes, for example, a preparation step of preparing a non-patterned laminate including a second electrode layer 5, a base film 2, a piezoelectric layer 3, and a first electrode layer 4. It includes a patterning step of patterning the first electrode layer 4, the piezoelectric layer 3, and the second electrode layer 5.

In the preparation process, a non-pattern laminated body is prepared.

First, the base film 2 is prepared, and the piezoelectric layer 3 is formed on the entire upper surface of the base film 2.

Examples of the method for forming the piezoelectric layer 3 include a wet method such as a coating method and a transfer method, and a dry method such as a vacuum vapor deposition method, a sputtering method, and an ion plating method. Preferably, the wet method is mentioned from the viewpoint of production efficiency, production equipment and the like.

In the coating method, for example, a coating liquid containing a piezoelectric material and a solvent is applied to the upper surface of the base film 2, and then the coating liquid is dried.

In the transfer method, for example, a known or commercially available piezoelectric sheet made of a piezoelectric material is attached to the upper surface of the base film 2 via an adhesive or the like.

Next, the first electrode layer 4 is formed on the upper surface of the piezoelectric layer 3 and the second electrode layer 5 is formed on the lower surface of the base film 2 by a dry method.

Examples of the dry method include a vacuum deposition method, a sputtering method, an ion plating method and the like. Preferably, a sputtering method is used. By this method, a thin transparent electrode layer can be reliably formed.

Next, when the material constituting the first electrode layer 4 and the second electrode layer 5 is an amorphous material such as ITO, a heating step is carried out if necessary. As a result, the amorphous body can be crystallized.

In this way, a non-patterned laminate including the second electrode layer 5, the base film 2, the piezoelectric layer 3, and the first electrode layer 4 can be obtained. Each layer in this non-patterned laminate is not patterned. That is, each layer is composed of one continuous sheet.

In the patterning step, the non-patterned laminate is patterned.

For example, the top and bottom surfaces of the non-patterned laminate are coated with a mask of the desired pattern, followed by etching the top and bottom surfaces exposed from the mask, respectively. The etching may be either dry etching or wet etching.

As a result, the second electrode layer 5 is patterned to form a plurality of second electrode portions 8 and a plurality of second wiring portions 13. The first electrode layer 4 is patterned to form a plurality of first electrode portions 7 and a plurality of first wiring portions 12. The piezoelectric layer 3 is patterned to form a plurality of piezoelectric portions 6 and a plurality of wiring lower portions 11.

At this time, the piezoelectric layer 3 and the first electrode layer 4 may be etched together on the upper surface of the non-patterned laminate, or the piezoelectric layer 3 may be etched after the first electrode layer 4 is etched.

Further, in this manufacturing method, each layer can be provided on the base film 2 by, for example, a roll-to-roll method, or a part or all of these layers are provided by a batch method (single-leaf method). You can also do it.

The thickness of the piezoelectric laminate 1 is, for example, 3 μm or more, preferably 20 μm or more, and for example, 500 μm or less, preferably 300 μm or less.

The piezoelectric laminate 1 can be suitably used as a component of the pressure sensor 10.

As shown in FIG. 2, the pressure sensor 10 includes a piezoelectric laminate 1, a plurality of voltmeters 14, and an integrated circuit (not shown).

The plurality of voltmeters 14 are provided in the middle of the first wiring portion 12 or the second wiring portion 13 corresponding to the plurality of piezoelectric portions 6. In the pressure sensor 10, the second wiring portion 13 is grounded.

The pressure sensor 10 provided with the piezoelectric laminate 1 can be suitably used as, for example, a film for a touch panel.

<Effect>
The piezoelectric laminate 1 includes a piezoelectric layer 3, a first electrode layer 4 arranged on the upper side of the piezoelectric layer 3, and a second electrode layer 5 arranged on the lower side of the piezoelectric layer 3. Further, the first electrode layer 4 has a plurality of independent first electrode portions 7, and the piezoelectric layer 3 has a plurality of independent piezoelectric portions 6 corresponding to the plurality of first electrode portions 7. doing.

That is, since the plurality of piezoelectric portions 6 correspond to the plurality of first electrode portions 7 and exist independently of the adjacent piezoelectric portions 6, the voltage generated in one piezoelectric portion 6 is generated by the other adjacent piezoelectric portions 6. Does not conduct to the independent piezoelectric portion 6. Therefore, the piezoelectric unit 6 that detects the touch does not affect the generation of the voltage with respect to the other independent piezoelectric unit 6, and no voltage is generated other than the piezoelectric unit 6 that detects the touch. Therefore, only the current generated from the piezoelectric portion 6 that has detected the touch can be detected through the first electrode portion 7 arranged on the upper surface thereof. As a result, erroneous touch detection can be suppressed.

Further, the piezoelectric laminate 1 further includes a base film 2 arranged between the piezoelectric layer 3 and the second electrode layer 5.

Therefore, the mechanical strength of the piezoelectric laminate 1 is increased, and the durability is excellent.

Further, in the piezoelectric laminate 1, the second electrode layer 5 has a plurality of independent second electrode portions 8 corresponding to the plurality of independent first electrode portions 7.

Therefore, the piezoelectric laminate 1 includes a first electrode portion 7 and a second electrode portion 8 for each piezoelectric portion 6, respectively. Therefore, since one independent circuit can be formed corresponding to each piezoelectric portion 6, the influence on the adjacent piezoelectric portion 6 can be suppressed. Therefore, noise reduction can be reduced, and erroneous detection of the touch position can be suppressed more reliably.

Further, in the piezoelectric laminate 1, the first electrode portion 7 coincides with the piezoelectric portion 6 when projected in the thickness direction.

According to the piezoelectric laminate 1, since the entire first electrode portion 7 is arranged on the upper side of the entire piezoelectric portion 6, an electric charge is formed in the vertical direction between the first electrode portion 7 and the base film 2. There is no air layer (see reference numeral 15 in FIG. 3B described later) in which the electric charge is easily stored. Therefore, it is possible to suppress the generation of unnecessary charges in the middle, that is, it is possible to eliminate unnecessary charges generated in areas other than the piezoelectric portion 6, and thus noise can be suppressed. Therefore, erroneous detection of the touch position can be suppressed more reliably.

<Modification example>
Next, a modified example of one embodiment is shown. In each of the following drawings, the same members as described above are designated by the same reference numerals, and the description thereof will be omitted.

(1) In the embodiment shown in FIG. 1A, the first electrode portion 7 coincides with the piezoelectric portion 6 when projected in the thickness direction. However, for example, as shown in FIG. 3A, the first electrode portion 7 May be included in the piezoelectric portion 6 when projected in the thickness direction.

In other words, the pattern of the first electrode portion 7 is smaller than the pattern of the piezoelectric portion 6 and the second electrode portion 8. Specifically, the peripheral edge of the first electrode portion 7 is located inside the peripheral edge of the piezoelectric portion 6.

The embodiment shown in FIG. 3A also has the same effect as that of the embodiment shown in FIG. 1A.

(2) In the embodiment shown in FIG. 1A, the first electrode portion 7 coincides with the piezoelectric portion 6 when projected in the thickness direction. For example, as shown in FIG. 3B, the piezoelectric portion 6 has a piezoelectric portion 6. It may be included in the first electrode portion 7 when projected in the thickness direction.

In other words, the pattern of the piezoelectric portion 6 is smaller than the pattern of the first electrode portion 7 and the second electrode portion 8. Specifically, the peripheral edge of the piezoelectric portion 6 is located inside the peripheral edge of the first electrode portion 7.

Preferably, from the viewpoint of noise suppression, the embodiments shown in FIGS. 1A and 3A can be mentioned.

(3) In the embodiment shown in FIG. 1A, the second electrode layer 5 has a plurality of second electrode portions 8 corresponding to the plurality of first electrode portions 7, but is shown in FIG. 4, for example. As described above, the second electrode layer 5 may be composed of one second electrode portion 8.

The second electrode portion 8 shown in FIG. 4 includes all the piezoelectric portions 6 and all the first electrode portions 7 when projected in the thickness direction. That is, the pattern of the second electrode portion 8 is larger than the patterns of all the piezoelectric portions 6 and the first electrode portion 7, and the peripheral edge of the second electrode portion 8 is the outer edge of the piezoelectric portion 6 located on the outside. It is located outside the outer edge of the first electrode portion 7 located outside the outer edge of the first electrode portion 7.

In this case, each piezoelectric portion 6 and the corresponding first electrode portion 7 share one second electrode portion 8.

From the viewpoint of suppressing the influence on the piezoelectric portions 6 adjacent to each other and more reliably suppressing the generation of noise, the embodiment shown in FIG. 1A is preferable.

Further, in the embodiment shown in FIG. 4, the first electrode portion 7 coincides with the piezoelectric portion 6 when projected in the thickness direction, but for example, although not shown, the first electrode portion 7 is in the thickness direction. It may be included in the piezoelectric portion 6 when projected onto. Further, for example, although not shown, the piezoelectric portion 6 may be included in the first electrode portion 7 when projected in the thickness direction.

Preferably, from the viewpoint of noise suppression, the first electrode portion 7 coincides with the piezoelectric portion 6 or is included in the piezoelectric portion 6.

(4) In the embodiment shown in FIG. 1A, the piezoelectric laminate 1 includes the base film 2, but for example, as shown in FIG. 5, the piezoelectric laminate 1 does not include the base film 2. May be good.

That is, the piezoelectric laminate 1 includes a piezoelectric layer 3, a first electrode layer 4 arranged on the upper side of the piezoelectric layer 3, and a second electrode layer 5 arranged on the lower side of the piezoelectric layer 3. Specifically, the piezoelectric laminate 1 includes a second electrode layer 5, a piezoelectric layer 3, and a first electrode layer 4 in this order.

In the embodiment shown in FIG. 6, the second electrode layer 5 is arranged below the piezoelectric layer 3 so as to be in contact with the lower surface of the piezoelectric layer 3.

Preferably, from the viewpoint of mechanical strength, the embodiment shown in FIG. 1A can be mentioned.

Further, in the embodiment shown in FIG. 5, the first electrode portion 7 coincides with the piezoelectric portion 6 when projected in the thickness direction. For example, although not shown, the first electrode portion 7 is in the thickness direction. It may be included in the piezoelectric portion 6 when projected onto. Further, for example, although not shown, the piezoelectric portion 6 may be included in the first electrode portion 7 when projected in the thickness direction.

Preferably, from the viewpoint of noise suppression, the first electrode portion 7 coincides with the piezoelectric portion 6 or is included in the piezoelectric portion 6.

(5) In the embodiment shown in FIG. 1A, the second electrode layer 5 has a plurality of second electrode portions 8 corresponding to the plurality of first electrode portions 7, and includes a base film 2. However, for example, as shown in FIG. 6, the second electrode layer 5 is composed of one second electrode portion 8, and the piezoelectric laminate 1 does not have to include the base film 2.

The specific configuration is the same as that of the embodiments described in (3) and (4) above.

Preferably, the embodiment shown in FIG. 1A is mentioned from the viewpoint of suppressing the influence on the piezoelectric portions 6 adjacent to each other and more reliably suppressing the erroneous detection of the touch position and improving the mechanical strength.

Further, in the embodiment shown in FIG. 6, the first electrode portion 7 coincides with the piezoelectric portion 6 when projected in the thickness direction. For example, although not shown, the first electrode portion 7 is in the thickness direction. It may be included in the piezoelectric portion 6 when projected onto. Further, for example, although not shown, the piezoelectric portion 6 may be included in the first electrode portion 7 when projected in the thickness direction.

Preferably, from the viewpoint of noise suppression, the first electrode portion 7 coincides with the piezoelectric portion 6 or is included in the piezoelectric portion 6.

(6) In the embodiment shown in FIG. 1A, the piezoelectric portion 6, the first electrode portion 7, and the second electrode portion 8 are each formed in a substantially rectangular shape in a plan view, but their shapes are limited. However, for example, although not shown, it may be formed in a hexagonal shape, a diamond shape, a circular shape, or the like.

Further, the sizes of the plurality of piezoelectric portions 6 are the same as each other, but for example, although not shown, they may be different sizes. Specifically, the size of the piezoelectric portion 6 in the central portion is increased to increase the outer edge. The size of the piezoelectric portion 6 of the portion may be reduced. The same applies to the first electrode portion 7 and the second electrode portion 8.

1 Piezoelectric laminate 2 Base film 3 Piezoelectric layer 4 First electrode layer 5 Second electrode layer 6 Piezoelectric part 7 First electrode part 8 Second electrode part

Claims (11)

Piezoelectric layer and
The first electrode layer arranged on one side in the thickness direction of the piezoelectric layer and
A second electrode layer arranged on the other side of the piezoelectric layer in the thickness direction ,
A base film provided between the piezoelectric layer and the second electrode layer is provided.
The first electrode layer has a plurality of independent first electrode portions arranged at intervals from each other.
A piezoelectric laminate, wherein the piezoelectric layer has a plurality of independent piezoelectric portions arranged at intervals from each other corresponding to the plurality of first electrode portions. The first electrode layer further has a plurality of first wiring portions, and one first wiring portion is connected to each of the first electrode portions.
The piezoelectric layer further and optionally wherein Rukoto has a plurality of wiring lower supporting said plurality of first wiring portion, a piezoelectric laminate according to claim 1. The piezoelectric laminate according to claim 1 or 2, wherein the second electrode layer has a plurality of independent second electrode portions corresponding to the plurality of first electrode portions. The first electrode portion according to any one of claims 1 to 3, wherein the first electrode portion coincides with the piezoelectric portion or is included in the piezoelectric portion when projected in the thickness direction. Piezoelectric laminate. The piezoelectric laminate according to any one of claims 1 to 4, wherein the first electrode layer and the second electrode layer are transparent electrode layers. The piezoelectric laminate according to any one of claims 1 to 5, wherein the piezoelectric layer is a resin layer. The piezoelectric laminate according to claim 6, wherein the resin layer contains a fluororesin. The piezoelectric laminate according to claim 7, wherein the fluororesin is a vinylidene fluoride-based resin. The vinylidene fluoride-based resin is polyvinylidene fluoride, or
The piezoelectric laminate according to claim 8, wherein the piezoelectric laminate is a copolymer of vinylidene fluoride and at least one of trifluoroethylene and chlorotrifluoroethylene. The vinylidene fluoride-based resin is a vinylidene fluoride-trifluoroethylene copolymer, and the molar ratio of vinylidene fluoride to trifluoroethylene is 100 as a whole, (50 to 85) :( 50 to 15). The piezoelectric laminate according to claim 9, wherein the piezoelectric laminate is characterized by the above. The vinylidene fluoride-based resin is a vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene copolymer, and the molar ratio of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene is 100 as a whole. 63 to 65) :( 27 to 29): (6 to 10). The piezoelectric laminate according to claim 9.

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