TWI678520B - Piezoelectric sensor - Google Patents

Abstract

A piezoelectric inductor includes a substrate, an electrode array, a plurality of flexible piezoelectric material layers, and at least a pair of spacers. The electrode array is disposed on the substrate. A plurality of flexible piezoelectric material layers are laminated on each other on the electrode array. The spacers are respectively disposed on opposite sides of the electrode array and between two adjacent flexible piezoelectric material layers.

Description

Piezoelectric Inductor

The present invention relates to a sensor, and in particular to a piezo-inductive sensor.

In recent years, with the increasing development of the technology industry, portable electronic devices that are convenient for users to carry, such as laptops, tablets, and smart phones, and even electronic products that can be worn directly on users Wearable electronic devices have frequently appeared in daily life.

The portable electronic device can be matched with different devices or sensors according to user needs to increase the functions of electronic products. For example, the portable electronic device can be configured with functions such as communication, audio and video playback, web browsing, heartbeat detection, blood pressure detection, etc., as required. However, under the circumstances that the size of the portable electronic device is limited, the physiological conditions of the user or the use environment are different, the performance of the electronic device will be unsatisfactory. For example, a heartbeat sensor mounted on a portable electronic device often causes insufficient signal-to-noise (S / N) due to low output signal strength.

The invention provides a piezo-inductor detector with a good signal-to-noise ratio.

The piezoelectric inductor of the present invention includes a substrate, an electrode array, a plurality of flexible piezoelectric material layers, and at least a pair of spacers. The electrode array is disposed on the substrate. The flexible piezoelectric material layers are laminated on each other on the electrode array. The spacers are respectively disposed on opposite sides of the electrode array and between two adjacent flexible piezoelectric material layers.

Based on the above, in the piezoelectric sensor of the embodiment of the present invention, the spacers are respectively disposed on opposite sides of the electrode array and between two adjacent flexible piezoelectric material layers, so that the two adjacent The number of vibrations between the flexible piezoelectric material layers increases to cause more deformation, thereby increasing the strength of the pressure output signal. On the other hand, multiple layers of flexible piezoelectric material are laminated on the electrode array, so that the total thickness of the piezoelectric material can be increased by stacking the layers of flexible piezoelectric material, thereby enhancing the strength of the output signal. Therefore, the piezoelectric inductor of the embodiment of the present invention can have a good signal-to-noise ratio.

In order to make the above features and advantages of the present invention more comprehensible, embodiments are hereinafter described in detail with reference to the accompanying drawings.

In the drawings, the thicknesses of layers, films, panels, regions, etc. are exaggerated for clarity. Throughout the description, the same reference numerals denote the same elements. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element, or Intermediate elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. As used herein, "connected" may refer to a physical and / or electrical connection. Furthermore, "electrically connected" or "coupled" can mean that there are other components between the two components.

As used herein, "about," "approximately," or "substantially" includes the stated value and an average value within an acceptable range of deviations from a particular value determined by one of ordinary skill in the art, taking into account the measurement in question And a specific number of measurement-related errors (ie, limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or within ± 30%, ± 20%, ± 10%, ± 5%. Furthermore, the terms "about", "approximately" or "substantially" used herein may select a more acceptable range of deviations or standard deviations based on optical properties, etching properties, or other properties, and all properties can be applied without one standard deviation. .

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted to have meanings consistent with their meanings in the context of the related art and the present invention, and will not be interpreted as idealized or excessive Formal meaning unless explicitly defined as such in this article.

FIG. 1 is a schematic cross-sectional view of a piezoelectric inductor according to an embodiment of the present invention. FIG. 2A is a schematic top view of a piezoelectric inductor according to an embodiment of the present invention. FIG. 2B is a schematic top view of a piezoelectric inductor according to another embodiment of the present invention. FIG. 2C is a schematic top view of a piezoelectric inductor according to another embodiment of the present invention. The flexible piezoelectric material layer and the analysis device shown in FIG. 1 are omitted from FIGS. 2A to 2C to clearly show the pattern of the spacer and the relative position between the spacer and the electrode array.

Referring to FIG. 1, the piezoelectric sensor 100 includes a substrate S, an electrode array EA, a plurality of flexible piezoelectric material layers FP, and at least a pair of spacers SP. In this embodiment, the piezoelectric inductive sensor 100 can be used as a sensor for measuring a pulse signal to obtain a user's pulse heart rate or pulse pattern.

The electrode array EA is disposed on the substrate S, and the flexible piezoelectric material layers FP are laminated on each other on the electrode array EA. In this way, when the flexible piezoelectric material layer FP is deformed due to vibration caused by an external force, the electrode array EA can detect the voltage generated by the flexible piezoelectric material layer FP due to the deformation, and the subsequent To the analysis device AD to quantify the data. For example, when the piezoelectric inductive sensor 100 is used as a sensor for measuring pulse signals, a user's wrist can be compared with the uppermost layer of the flexible piezoelectric material layer FP (ie, the most flexible piezoelectric material) in the piezoelectric inductive sensor 100. The flexible piezoelectric material layer FP) far from the substrate S is in contact. In this way, the electrode array EA can detect the voltage generated by the deformation of the flexible piezoelectric material layer FP caused by the undulation of the wrist pulse, so as to obtain the user's heart rate or pulse.

In this embodiment, the total thickness of the piezoelectric material in the piezoelectric sensor 100 can be increased by a plurality of flexible piezoelectric material layers FP laminated on the electrode array EA, so that the piezoelectricity can be reduced. The resistance generated by a capacitor, thereby increasing the strength of an output signal (such as a voltage). In this way, the piezoelectric inductive sensor 100 can have a good signal-to-noise ratio. In this embodiment, when the flexible piezoelectric material layer FP is not subjected to an external force, the flexible piezoelectric material layer FP may not be in contact with the electrode array EA. In this embodiment, an example is described in which four flexible piezoelectric material layers FP are stacked on the electrode array EA, but the present invention is not limited thereto.

The material of the electrode array EA may be a conductive material, such as a metal, a metal oxide, a metal nitride, a metal oxynitride, or a combination thereof. The substrate S may be a flexible substrate. For example, the material of the substrate S may include a flexible material such as polyimide (PI). The material of the flexible piezoelectric material layer FP may include polyvinylidene fluoride (PVDF), a copolymer of polyvinylidene fluoride, or a combination thereof. The copolymer of polyvinylidene fluoride may be, for example, polyvinylidenefluoride-co-trifluoroethylene (PVDF-TrFE), polyvinylidene fluoride-tetrafluoroethylene copolymer (poly (vinylidene fluoride) -co-tetrafluoroethylene)) or vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP).

Please refer to FIG. 1 and FIG. 2A at the same time. In this embodiment, the electrode array EA may include a plurality of first electrodes E1, and the first electrodes E1 are not electrically connected to each other. In this way, the array of multiple first electrodes E1 can be used to effectively measure the pulse signals at different positions of the wrist (such as the inch, off, and ruler mentioned in traditional Chinese medicine) to make a three-dimensional position and pulse signal strength. Schematic (for example, the xy plane represents the measurement position, and the z-axis represents the signal strength), so that the data can be quantified to determine the pulse of TCM corresponding to the pulse signal. The material of the first electrode E1 may be a conductive material, such as a metal, a metal oxide, a metal nitride, a metal oxynitride, or a combination thereof. In this embodiment, a material of the first electrode E1 may be indium tin oxide (ITO). The electrode array EA in FIG. 2A is described by using the first electrode E1 including nine squares as an example, but the present invention is not limited thereto. In other embodiments, the electrode array EA may include first electrodes E1 of different shapes or numbers.

The piezoelectric inductive sensor 100 may include an analysis device AD. The analysis device AD can be coupled to the electrode array EA, thereby quantifying the output signal of the flexible piezoelectric material layer FP. In some embodiments, the piezoelectric inductive sensor 100 may include a plurality of analysis devices AD, so that the flexible piezoelectric material layer FP can be obtained by respectively coupling the first electrode E1 to the corresponding analysis device AD. Output signals at different locations. In other words, the number of the analysis devices AD may correspond to the number of the first electrodes E1, but the invention is not limited thereto. In other embodiments, the piezoelectric sensor 100 may optionally include a multiplexer (not shown), so that the first electrodes E1 in the electrode array EA may be respectively coupled to the analysis by the multiplexer. The device AD is such that the number of the analysis devices AD does not need to correspond to the number of the first electrodes E1. In this embodiment, the analysis device AD may include an amplification circuit to enhance the strength of the output signal.

Please refer to FIG. 1 and FIG. 2A at the same time. The spacers SP are respectively disposed on opposite sides of the electrode array EA and between two adjacent flexible piezoelectric material layers FP. There is enough space between the piezoelectric material layers FP to perform more vibrations (such as d ₃₁ piezoelectric vibration mode and d ₃₃ piezoelectric vibration mode), thereby causing more deformation, thereby increasing the strength of the output signal. The d ₃₃ piezoelectric vibration mode mentioned above indicates that the electric field direction is parallel to the strain direction; and the d ₃₁ piezoelectric vibration mode indicates that the electric field direction is perpendicular to the strain direction.

The material of the spacer SP may include a dielectric material, such as an organic dielectric material, an inorganic dielectric material, or a combination thereof. The organic dielectric material may be a photoresist, a polyimide-based resin, an epoxy-based resin, an acrylic resin, other suitable organic dielectric materials, or a combination of at least two of the foregoing. Polymer materials such as polyimide resins, epoxy resins, and acrylic resins. The inorganic dielectric material may be silicon oxide, silicon nitride, silicon oxynitride, other suitable inorganic dielectric materials, or a combination of at least two of the foregoing.

In this embodiment, at least one pair of spacers SP may be spaced apart from each other and disposed on opposite sides of the electrode array EA, respectively, so that the flexible piezoelectric material layer FP is in the d ₃₁ piezoelectric vibration mode and d ₃₃ Good vibration amplitude in piezoelectric vibration mode. In this embodiment, the spacer SP may be in contact with two adjacent flexible piezoelectric material layers FP. In this embodiment, the spacers SP may be respectively disposed on opposite sides of the electrode array EA without overlapping with the adjacent first electrode E1, but the present invention is not limited thereto. In other embodiments, the spacers SP may be respectively disposed on opposite sides of the electrode array EA and partially overlap the adjacent first electrodes E1.

In this embodiment, as shown in FIG. 2A, the at least one spacer SP may be strip-shaped bumps spaced apart from each other and respectively disposed on opposite sides of the electrode array EA, but the present invention does not take this as The shape, size, number, and arrangement of the spacers SP can be adjusted according to design. For example, in some embodiments, as shown in FIG. 2B, each of the at least one pair of spacers SP may include a plurality of bumps BP, and the plurality of bumps BP in at least one pair of spacers SP may be spaced apart from each other And surround the electrode array EA. The pair of spacers SP in FIG. 2B is described by using an example including 40 square bumps BP, but the present invention is not limited thereto. In other embodiments, the spacers SP may also include bumps BP of different shapes or numbers. In other embodiments, as shown in FIG. 2C, at least one pair of spacers SP may contact each other to form a spacer pattern SPP that surrounds the electrode array EA.

FIG. 3 is a schematic cross-sectional view of a piezoelectric inductor according to still another embodiment of the present invention. The piezoelectric inductive sensor 100 is similar to the piezoelectric inductive sensor 200. The difference is that the piezoelectric inductive sensor 200 further includes a second electrode E2. Therefore, the same or similar components use the same or similar reference numerals, and the connection relationship of the remaining components , Materials and processes have been described in detail in the previous article, so they will not be repeated hereafter.

Referring to FIG. 3, the piezoelectric sensor 200 may further include a second electrode E2, wherein the second electrode E2 may be disposed on the flexible piezoelectric material layer of the flexible piezoelectric material layers FP farthest from the substrate S. FP. In this way, when the wrist is in contact with the uppermost flexible piezoelectric material layer FP, the second electrode E2 can reduce the interface resistance between the wrist and the flexible piezoelectric material layer FP to further enhance the output signal. The material of the second electrode E2 may be a conductive material, such as a metal, a metal oxide, a metal nitride, a metal oxynitride, or a combination thereof. The second electrode E2 may be a transparent conductive material or a non-transparent conductive material.

In summary, in the piezoelectric sensor of the above embodiment, the spacers are respectively disposed on opposite sides of the electrode array and between two adjacent flexible piezoelectric material layers, so that the two adjacent The number of vibrations between the flexible piezoelectric material layers increases to cause more deformation, thereby increasing the strength of the pressure output signal. On the other hand, a plurality of flexible piezoelectric material layers are laminated on each other on the electrode array. In this way, the total thickness of the piezoelectric material can be increased by stacking the flexible piezoelectric material layers to enhance the strength of the output signal. Therefore, the piezoelectric inductor of the above embodiment can have a good signal-to-noise ratio.

Although the present invention has been disclosed as above with the examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some modifications and retouching without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be determined by the scope of the attached patent application.

100, 200‧‧‧ Piezoelectric Inductor

S‧‧‧ substrate

EA‧‧‧electrode array

FP‧‧‧ Flexible Piezoelectric Material Layer

SP‧‧‧ spacer

E1‧‧‧First electrode

E2‧‧‧Second electrode

AD‧‧‧analytical device

BP‧‧‧ bump

SPP‧‧‧spacer pattern

FIG. 1 is a schematic cross-sectional view of a piezoelectric inductor according to an embodiment of the present invention.
FIG. 2A is a schematic top view of a piezoelectric inductor according to an embodiment of the present invention.
FIG. 2B is a schematic top view of a piezoelectric inductor according to another embodiment of the present invention.
FIG. 2C is a schematic top view of a piezoelectric inductor according to another embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view of a piezoelectric inductor according to still another embodiment of the present invention.

Claims (11)

A piezoelectric inductor includes: a substrate; an electrode array disposed on the substrate; a plurality of flexible piezoelectric material layers laminated on the electrode array; and at least a pair of spacers respectively provided Between two opposite sides of the electrode array and two adjacent flexible piezoelectric material layers. The piezoelectric inductive device according to item 1 of the patent application scope, wherein the at least one pair of spacers are spaced apart from each other. The piezoelectric inductive device as described in claim 1, wherein the at least one pair of spacers each include a plurality of bumps, and the bumps in the at least one pair of spacers are spaced apart from each other and surround the Electrode array. The piezoelectric sensor according to item 1 of the patent application scope, wherein the at least one pair of spacers are in contact with each other to form a spacer pattern surrounding the electrode array. The piezoelectric sensor according to item 1 of the patent application scope, wherein the electrode array includes a plurality of first electrodes, and the first electrodes are not electrically connected to each other. The piezoelectric inductive device according to item 1 of the patent application scope, wherein the at least one pair of spacers are in contact with two adjacent layers of flexible piezoelectric material. The piezoelectric inductive device according to item 1 of the patent application scope further includes: an analysis device coupled to the electrode array, and the analysis device includes an amplification circuit. The piezoelectric inductive device according to item 1 of the patent application scope further includes: a second electrode disposed on the flexible piezoelectric material layer of the flexible piezoelectric material layers farthest from the substrate. The piezoelectric inductive device as described in claim 1, wherein a material of the at least one pair of spacers includes a dielectric material. The piezoelectric inductive device according to item 1 of the patent application scope, wherein the flexible piezoelectric material layers include polyvinylidene fluoride (PVDF), a copolymer of polyvinylidene fluoride, or a combination thereof. The piezoelectric inductive device according to item 1 of the scope of patent application, wherein the flexible piezoelectric material layer farthest from the substrate among the plurality of flexible piezoelectric material layers is measured by a user's desire. Site contact.