Composite piezoelectric element and electronic device having the same

Abstract

Disclosed are a composite piezoelectric element and an electronic device having the composite piezoelectric element, wherein the composite piezoelectric element includes an insulating film and a piezoelectric body arranged alternately, wherein the piezoelectric body can be classified as a general piezoelectric body and a finger scan recognition piezoelectric body, the general piezoelectric body is used as at least one of a tactile actuator, a speaker actuator, and an earpiece actuator, and the finger scan recognition piezoelectric body is used for finger scan recognition.

Description

Technical Field

[0001] The present disclosure relates to a composite piezoelectric element implemented to perform various functions and an electronic device having the composite piezoelectric element. Background Art

[0002] Recently, with the development of high integration and advanced technology of electronic devices, various functions are built into the electronic devices.

[0003] For example, various functions such as display function, finger scan recognition function, tactile function and sound output function are built into portable electronic devices (e.g., cellular phones, etc.), and piezoelectric bodies can be used for the finger scan recognition function, tactile function and sound output function.

[0004] In the related art, since a device for performing each function is independently built into an electronic device, there are many difficulties in miniaturization and slimming of the electronic device.

[0005] In this regard, various studies have been conducted on integrated elements that are generally used in elements required to perform functions. For example, studies have been conducted on film-type piezoelectric bodies that are generally used to perform various functions. Summary of the Invention

[0006] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a film-type composite piezoelectric element that can perform various functions such as a tactile function, a speaker function, an earpiece function, and a finger scan recognition function.

[0007] Another object of the present invention is to provide an electronic device having a film-type composite piezoelectric element that can perform various functions to achieve miniaturization and slimming.

[0008] In addition to the objects of the present disclosure as described above, other objects and features of the present disclosure will be clearly understood by those skilled in the art from the following description of the present disclosure.

[0009] According to one aspect of the present disclosure, the above and other purposes can be achieved by providing a composite piezoelectric element, which includes: an insulating film and a piezoelectric body arranged alternately, wherein the piezoelectric body can be classified as a general piezoelectric body and a finger scan recognition piezoelectric body, the general piezoelectric body is used as at least one of a tactile actuator, a speaker actuator and a receiver actuator, and the finger scan recognition piezoelectric body is used for finger scan recognition.

[0010] All of the general piezoelectric bodies may be used as one of the haptic actuator, the speaker actuator, and the earpiece actuator.

[0011] The general piezoelectric bodies may be classified into a plurality of groups, and the general piezoelectric bodies included in the respective groups may be used as different actuators.

[0012] Some of the general piezoelectric bodies may be used as actuators for one function, while other general piezoelectric bodies may be used as actuators for complex functions.

[0013] The finger scan recognition piezoelectric body may include an ultrasonic oscillation piezoelectric body for oscillating ultrasonic waves for finger scan recognition; and an ultrasonic receiving piezoelectric body for receiving a reflection signal reflected by the ultrasonic waves oscillating from the ultrasonic oscillation piezoelectric body.

[0014] A first cavity may be formed in the ultrasonic oscillation piezoelectric body, and a second cavity may be formed in the ultrasonic reception piezoelectric body.

[0015] The first cavity may be formed at a depth at which the frequency of the ultrasonic wave oscillated by the ultrasonic oscillation piezoelectric body resonates, and the second cavity may be formed at a depth at which the frequency of the ultrasonic wave received by the ultrasonic reception piezoelectric body resonates.

[0016] The depth of the first cavity and the depth of the second cavity may be the same as or different from each other.

[0017] The depths of the first cavities formed in the ultrasonic oscillation piezoelectric body may be the same as or different from each other, and the depths of the second cavities formed in the ultrasonic reception piezoelectric body may be the same as or different from each other.

[0018] A polymer material may also be formed in at least one of the first cavity and the second cavity.

[0019] A height of the polymer material formed in the first cavity and a height of the polymer material formed in the second cavity may be the same as or different from each other.

[0020] The polymer material may be formed in all or some of the first cavities formed in the ultrasonic oscillation piezoelectric body, and the polymer material may be formed in all or some of the second cavities formed in the ultrasonic receiving piezoelectric body.

[0021] Respective heights of the polymer material formed in the first cavity may be the same as or different from each other, and respective heights of the polymer material formed in the second cavity may be the same as or different from each other.

[0022] The composite piezoelectric element may further include at least one of a metal film formed in the second cavity and a metal plate covering the second cavity.

[0023] According to another aspect of the present disclosure, the above and other purposes can be achieved by providing an electronic device, which includes: an ultrasonic sensor, which is used for finger scan recognition; and at least one or more actuators among a tactile actuator, a speaker actuator and an earpiece actuator, wherein the ultrasonic sensor and the at least one or more actuators can constitute a composite piezoelectric element.

[0024] An ultrasonic oscillating piezoelectric body and an ultrasonic receiving piezoelectric body constituting the ultrasonic sensor may be provided in the composite piezoelectric element, and a first cavity and a second cavity may be formed in the ultrasonic oscillating piezoelectric body and the ultrasonic receiving piezoelectric body, respectively.

[0025] The polymer material may also be formed in at least one of the first cavity and the second cavity.

[0026] A metal film may also be formed in the second cavity, and a metal plate may also be formed to cover the second cavity.

[0027] A general piezoelectric body serving as at least one of the haptic actuator, the speaker actuator, and the earpiece actuator may be provided in the composite piezoelectric element.

[0028] Some of the general piezoelectric bodies may be used as actuators for one function, and other general piezoelectric bodies may be used as actuators for multiple functions.

[0029] Details of other implementations are included in the detailed description and accompanying drawings.

[0030] If the composite piezoelectric element according to the embodiment of the present disclosure is used, all of the various functions, such as a haptic function, a speaker function, an earpiece function, and a finger scan recognition function, can be implemented using one composite piezoelectric element.

[0031] Therefore, if an electronic device is implemented using the composite piezoelectric element according to an embodiment of the present disclosure, miniaturization and slimming of the electronic device can be achieved.

[0032] Furthermore, since the composite piezoelectric element according to the embodiment of the present disclosure is implemented in the form of a film, it is easy to change the position of the composite piezoelectric element.

[0033] Furthermore, since the composite piezoelectric element according to an embodiment of the present disclosure is implemented such that polymer insulating films and piezoelectric bodies are alternately arranged, a flexible composite piezoelectric element can be provided.

[0034] In addition to the effects of the present disclosure as described above, other advantages and features of the present disclosure will be clearly understood by those skilled in the art from the above description of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and other objects, features and other advantages of the present disclosure will be more clearly understood through the following detailed description taken in conjunction with the accompanying drawings, in which:

[0036] Figure 1 is a diagram showing a composite piezoelectric element according to a first embodiment of the present disclosure;

[0037] Figure 2 is shown along Figure 1 A cross-sectional view of the composite piezoelectric element taken along line AA';

[0038] Figure 3 is a cross-sectional view showing a composite piezoelectric element according to a second embodiment of the present invention;

[0039] Figure 4 is a cross-sectional view showing a composite piezoelectric element according to a third embodiment of the present invention;

[0040] Figure 5 is a graph showing a comparison curve of ultrasonic oscillation intensities in an ultrasonic oscillation piezoelectric body provided with a cavity and an ultrasonic oscillation piezoelectric body not provided with a cavity;

[0041] Figure 6 is a graph showing a comparison curve of ultrasound receiving sensitivities in an ultrasound receiving piezoelectric body provided with a cavity and an ultrasound receiving piezoelectric body not provided with a cavity;

[0042] Figure 7 is a block diagram illustrating an example of an electronic device provided with the composite piezoelectric element of the present disclosure; and

[0043] Figure 8 It shows Figure 7 A cross-sectional view of an example of a composite piezoelectric element is provided in FIG. DETAILED DESCRIPTION

[0044] The advantages and features of the present disclosure and their implementation methods will be illustrated by the following embodiments described with reference to the accompanying drawings. However, the present disclosure may be implemented in different forms and should not be construed as limited to the embodiments described herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete and will fully convey the scope of the present disclosure to those skilled in the art. Furthermore, the present disclosure is limited only by the scope of the claims.

[0045] The shapes, sizes, ratios, angles and quantities disclosed in the accompanying drawings for describing the embodiments of the present disclosure are merely examples, and therefore, the present disclosure is not limited to the details shown. Throughout the specification, the same reference numerals refer to the same elements. In the following description, when a detailed description of a related known function or configuration is determined to be unnecessarily obscuring the main points of the present disclosure, the detailed description will be omitted. Where "including", "having" and "comprising" described in this specification are used, another component may be added unless "only" is used. Unless otherwise stated, terms in the singular may include plural forms.

[0046] When explaining an element, even if there is no explicit description, the element should be interpreted as including a range of error.

[0047] When describing a positional relationship, for example, when the positional relationship is described as "~ above", "~ above", "~ below" and "next to", unless "only" or "directly" is used, one or more parts may be arranged between two other parts.

[0048] It should be understood that although the terms "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of this disclosure.

[0049] When describing the elements of the present disclosure, the terms "first," "second," etc. may be used. These terms are intended to distinguish the corresponding element from other elements, and the basis, order, or number of the corresponding elements are not limited by these terms. The expression that one element is "connected" or "coupled" to another element should be understood as meaning that the element can be directly connected or coupled to the other element, unless otherwise specified, or a third element can be inserted between the corresponding elements.

[0050] Therefore, in the present disclosure, a display device may include a display device itself, such as an LCM or OLED module, and may also include a complete set of devices as final consumer devices or an application product including the LCM or OLED module.

[0051] For example, if the display panel is an organic light emitting display module (OLED) display panel, the display panel may include a plurality of gate lines and data lines, and pixels formed in the intersection area of ​​the gate lines and the data lines. In addition, the display panel may include: an array substrate including a thin film transistor as an element for selectively applying a voltage to each pixel; an organic light emitting diode (OLED) layer located on the array substrate; and an encapsulation substrate arranged on the array substrate to cover the OLED layer.

[0052] The encapsulation substrate can protect the thin film transistor and OLED layer from external impact and prevent water or oxygen from penetrating into the OLED layer. The layers formed on the array substrate may include an inorganic light-emitting layer, such as a nano-sized material layer or quantum dots.

[0053] The features of the various embodiments of the present disclosure may be coupled or combined with each other in part or in whole, and may be variously interoperable and technically driven as those skilled in the art will fully appreciate. The embodiments of the present disclosure may be performed independently of each other, or may be performed together in a mutually dependent relationship.

[0054] Hereinafter, a composite piezoelectric element and an electronic device having the same according to preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings and examples.

[0055] Figure 1 FIG is a diagram showing a composite piezoelectric element according to a first embodiment of the present invention, Figure 2 is shown along Figure 1 A cross-sectional view of the composite piezoelectric element taken along line AA'.

[0056] Reference Figure 1 and 2 Composite piezoelectric element 100 according to the first embodiment of the present invention may be provided in the form of a film having a predetermined thickness, and may include insulating films 110 and piezoelectric bodies 130 that are alternately arranged.

[0057] In this embodiment, the insulating film 110 and the piezoelectric body 130 are arranged in one direction (the left-right direction based on the drawing), but the arrangement structure of the insulating film 110 and the piezoelectric body 130 may be changed in various ways.

[0058] Composite piezoelectric element 100 can be implemented for various applications, such as a haptic actuator, a speaker actuator, an earpiece actuator, a finger scan recognition actuator, etc., but composite piezoelectric element 100 is not limited to this embodiment.

[0059] In order to make the composite piezoelectric element 100 usable for various applications, the piezoelectric body 130 may be formed to have different properties depending on the intended use. For example, the piezoelectric body 130 may be formed to generate waves of different wavelengths.

[0060] For example, insulating film 110 may be formed in a plate shape having a predetermined thickness, and a soluble polymer material (eg, polymer matrix) may be used as insulating film 110. If insulating film 110 is formed of a soluble polymer material, flexible composite piezoelectric element 100 may be manufactured.

[0061] The length L1 , thickness T1 , and width W1 of insulating film 110 may be determined in various ways depending on the intended use of composite piezoelectric element 100 , the specifications and structure of electronic equipment to which composite piezoelectric element 100 is applied, and the like.

[0062] The piezoelectric body 130 may be formed of a rectangular plate having a predetermined thickness, such as piezoelectric ceramics. The piezoelectric body 130 may be formed of a piezoelectric material such as PZT (Pb, Zr, Ti), NKN (Na, K, Nb), and BNT (Bi, Na, Ti).

[0063] The piezoelectric body 30 may be formed of various piezoelectric materials and may include barium titanate, lead titanate, lead zirconate titanate, potassium niobate, lithium niobate, lithium tantalate, sodium tungstate, zinc oxide, sodium potassium niobate, bismuth ferrite, sodium niobate, bismuth titanate, etc. However, the piezoelectric body 30 may be formed of a fluoride polymer or a copolymer thereof.

[0064] The length L2, thickness T2, and width W2 of piezoelectric body 30 can be determined in various ways depending on the intended use of composite piezoelectric element 100, the specifications and structure of the electronic device to which composite piezoelectric element 100 is applied, and the like.

[0065] According to an embodiment, the length L2, thickness T2, and width W2 of the piezoelectric body 130 may be equal to the length L1, thickness T1, and width W1 of the insulating film 110, but may be different from at least one or more of the length L, thickness T, and width W.

[0066] Hereinafter, piezoelectric body 130 will be described by classifying piezoelectric body 130 into general piezoelectric body 131 and finger scan recognition piezoelectric bodies 133 and 135. The number, shape, and arrangement structure of general piezoelectric body 131 and finger scan recognition piezoelectric bodies 133 and 135 can be changed in various ways in consideration of details related to the type and purpose of use of electronic equipment to which composite piezoelectric element 100 is applied, the purpose of use of composite piezoelectric element 100, and the like.

[0067] Generally, the piezoelectric body 131 can be used as a haptic actuator, a speaker actuator, or an earpiece actuator.

[0068] According to the embodiment, the piezoelectric body 130 may be used as an actuator for one use purpose, or may be used as an actuator for two use purposes.

[0069] For example, one general piezoelectric body 131 may be used as any one of a haptic actuator, a speaker actuator, and an earpiece actuator.

[0070] Alternatively, one general piezoelectric body 131 may be used as two or more of a haptic actuator, a speaker actuator, and an earpiece actuator.

[0071] According to an embodiment, all of the general piezoelectric bodies 131 may be used for one use purpose, or may be used for different use purposes by being classified into some groups for different use purposes.

[0072] For example, all general piezoelectric bodies 131 constituting composite piezoelectric element 100 may be used as any of a haptic actuator, a speaker actuator, and an earpiece actuator.

[0073] Alternatively, the first group of general piezoelectric bodies 131 constituting the composite piezoelectric element 100 can be used as actuators for a first purpose (e.g., a tactile actuator), the second group can be used as actuators (e.g., a speaker actuator), and the third group can be used as actuators for a third purpose (e.g., an earpiece actuator).

[0074] Although the above description is based on classifying general piezoelectric bodies 131 into three groups, the number of general piezoelectric bodies 131 may be determined according to the purpose of use of composite piezoelectric element 100 .

[0075] According to an embodiment, some of the general piezoelectric bodies 131 constituting the composite piezoelectric element 100 may be used for one purpose, while other general piezoelectric bodies 131 may be used for multiple purposes.

[0076] For example, a first group of general piezoelectric bodies 131 constituting composite piezoelectric element 100 may be used as a speaker actuator, and a second group may be used as a haptic actuator and an earpiece actuator.

[0077] The finger scan recognition piezoelectric body may include an ultrasonic oscillation piezoelectric body 133 for oscillating ultrasonic waves (e.g., 10 MHz to 50 MHz) for finger scan recognition, and an ultrasonic receiving piezoelectric body 135 for receiving a reflected signal reflected by the ultrasonic waves oscillated from the ultrasonic oscillation piezoelectric body 133. Thus, the finger scan recognition piezoelectric body may function as an ultrasonic sensor.

[0078] According to an embodiment, if a voltage is applied to the ultrasonic oscillation piezoelectric body 133 under the control of a control device (not shown), the ultrasonic oscillation piezoelectric body 133 can be vibrated to produce an oscillating ultrasonic wave, and the ultrasonic receiving piezoelectric body 135 can be vibrated by the incident ultrasonic wave and can receive the ultrasonic signal through the voltage difference generated by the vibration.

[0079] In order to improve the ultrasonic oscillation intensity and receiving sensitivity by using the resonance principle, cavities 133a and 135a can be formed in the ultrasonic oscillation piezoelectric body 133 and the ultrasonic receiving piezoelectric body 135, respectively, and considering the unique frequencies, the cavities 133a and 135a can have such a depth that the unique frequency of the material of the piezoelectric bodies 133 and 135 and the unique frequency of the material in the cavities 133a and 135a resonate.

[0080] The cavity 133 a (first cavity) may be formed to enhance the ultrasonic oscillation intensity of the ultrasonic oscillation piezoelectric body 133 , and the cavity 135 a (second cavity) may be formed to improve the ultrasonic reception sensitivity of the ultrasonic reception piezoelectric body 135 .

[0081] According to an embodiment, based on the corresponding drawings, cavities 133a and 135a may be formed on the upper surface of the ultrasonic oscillation piezoelectric body 133 and the upper surface of the ultrasonic receiving piezoelectric body 135. That is, the cavity 133a may be formed on the surface that does not contact the insulating film 110 among the surfaces of the ultrasonic oscillation piezoelectric body 133, and the cavity 135a may be formed on the surface that does not contact the insulating film 110 among the surfaces of the ultrasonic receiving piezoelectric body 135.

[0082] According to an embodiment, the cavities 133a and 135a may be formed in, but not limited to, a rectangular cube having a predetermined depth, width, and length. For example, the cavities 133a and 135a may be formed as a cube having a curved bottom surface.

[0083] exist Figure 2 In the embodiment, the cavities 133a and 135a may be formed in pairs at predetermined intervals in each of the ultrasonic oscillation piezoelectric body 133 and the ultrasonic receiving piezoelectric body 135. However, the number of the cavities 133a and 135a formed in the ultrasonic oscillation piezoelectric body 133 and the ultrasonic receiving piezoelectric body 135 is not limited to Figure 2 .

[0084] According to an embodiment, the number of the cavities 133 a and 135 a formed in the ultrasonic oscillation piezoelectric body 133 and the ultrasonic receiving piezoelectric body 135 may be 1 or 3 or more.

[0085] exist Figure 2In the embodiment, the cavities 133a and 135a may be formed in each of the ultrasonic oscillation piezoelectric body 133 and the ultrasonic receiving piezoelectric body 135 to have the same number. However, according to an embodiment, the number of cavities 133a formed in the ultrasonic oscillation piezoelectric body 133 may be different from the number of cavities 235a formed in the ultrasonic receiving piezoelectric body 135.

[0086] The number of the cavities 133a and 135a may be determined in consideration of each width of the cavities 133a and 135a, each width of the ultrasonic oscillation piezoelectric body 133 and the ultrasonic receiving piezoelectric body 135, and the like to improve ultrasonic oscillation intensity and reception sensitivity.

[0087] exist Figure 2 In the figure, the cavity 133a formed in the ultrasonic oscillation piezoelectric body 133 and the cavity 135a formed in the ultrasonic receiving piezoelectric body 135 have the same width and depth, the widths and depths of the cavity 133a formed in the ultrasonic oscillation piezoelectric body 133 are the same as each other, and the widths and depths of the cavity 135a formed in the ultrasonic receiving piezoelectric body 135 are the same as each other.

[0088] According to an embodiment, at least one of each width and depth of the cavity 133 a formed in the ultrasonic oscillation piezoelectric body 133 and each width and depth of the cavity 135 a formed in the ultrasonic receiving piezoelectric body 135 may be different from the other widths and depths.

[0089] According to an embodiment, at least one of each width and depth of the cavity 133a formed in the ultrasonic oscillation piezoelectric body 133 may be different from the other widths and depths, and at least one of each width and depth of the cavity 135a formed in the ultrasonic receiving piezoelectric body 135 may be different from the other widths and depths.

[0090] Each width and depth of the cavities 133 a and 135 a may be determined in consideration of each width and depth of the ultrasonic oscillation piezoelectric body 133 , the ultrasonic receiving piezoelectric body 135 , and the like to improve ultrasonic oscillation intensity and reception sensitivity.

[0091] exist Figure 2 In the embodiment, the cavities 133a and 135a are formed with the same length in one direction. However, the lengths of the cavities 133a and 135a may be different from each other, and the cavities 133a and 135a may be formed in different directions.

[0092] According to an embodiment, the length of the cavity 133 a of the ultrasonic oscillation piezoelectric body 133 and the length of the cavity 135 a of the ultrasonic receiving piezoelectric body 135 may be different from each other.

[0093] According to an embodiment, respective lengths of the cavities 133 a of the ultrasonic oscillation piezoelectric body 133 may be different from each other, and respective lengths of the cavities 135 a of the ultrasonic reception piezoelectric body 135 may be different from each other.

[0094] According to an embodiment, a length direction of the cavity 133 a of the ultrasonic oscillation piezoelectric body 133 and a length direction of the cavity 135 a of the ultrasonic receiving piezoelectric body 135 may be different from each other.

[0095] According to an embodiment, respective length directions of the cavity 133 a of the ultrasonic oscillation piezoelectric body 133 may be different from each other, and respective length directions of the cavity 135 a of the ultrasonic receiving piezoelectric body 135 may be different from each other.

[0096] Each length of the cavities 133 a and 135 a and each length direction of the cavities 133 a and 135 a may be determined to improve the ultrasonic oscillation intensity of the ultrasonic oscillation piezoelectric body 133 and the ultrasonic receiving sensitivity of the ultrasonic receiving piezoelectric body 135 .

[0097] Figure 3 is a cross-sectional view showing a composite piezoelectric element according to a second embodiment of the present disclosure.

[0098] Hereinafter, among the elements of the composite piezoelectric element 100' according to the second embodiment, the same elements as those of the composite piezoelectric element 100 according to the first embodiment will be omitted or described, if necessary, and the same figure marks will be given to the same elements as those of the composite piezoelectric element 100 according to the first embodiment.

[0099] The composite piezoelectric element 100 ′ according to the second embodiment differs from the composite piezoelectric element 100 according to the first embodiment in that polymer materials 151 and 153 are formed in the cavity 133 a of the ultrasonic oscillation piezoelectric body 133 and the cavity 135 a of the ultrasonic receiving piezoelectric body 135 .

[0100] exist Figure 3 In the embodiment, the polymer materials 151 and 153 are formed in the cavities 133a and 135a of the finger scan recognition piezoelectric bodies 133 and 135, but the present disclosure is not limited to Figure 3 .

[0101] According to an embodiment, the polymer material may be formed in only one of the cavity 133 a of the ultrasound oscillation piezoelectric body 133 and the cavity 135 a of the ultrasound reception piezoelectric body 135 .

[0102] That is, the polymer material may be formed only in the cavity 133 a of the ultrasonic oscillation piezoelectric body 133 , or the polymer material may be formed only in the cavity 135 a of the ultrasonic reception piezoelectric body 135 .

[0103] According to an embodiment, the polymer material may be formed only in some of the cavities 133 a of the ultrasound oscillation piezoelectric body 133 , or the polymer material may be formed only in some of the cavities 135 a of the ultrasound reception piezoelectric body 135 .

[0104] exist Figure 3 , the polymer materials 151 and 153 are formed at the same height as the cavities 133a and 135a of the finger scan recognition piezoelectric bodies 133 and 135. That is, although the polymer materials 151 and 153 may be formed to completely fill the cavities 133a and 135a, the present disclosure is not limited to this example.

[0105] According to an embodiment, the polymer material 151 may be formed in the cavity 133a of the ultrasound oscillation piezoelectric body 133 to completely fill the cavity 133a, and the polymer material 153 may be formed in the cavity 135a of the ultrasound reception piezoelectric body 135 to partially fill the cavity 135a.

[0106] According to an embodiment, the polymer material 151 may be formed in some cavities 133 a of the ultrasonic oscillation piezoelectric body 133 to completely fill the cavities 133 a , and may be formed in other cavities 133 a to partially fill the cavities 133 a .

[0107] According to an embodiment, the polymer material 153 may be formed in some cavities 135 a of the ultrasound receiving piezoelectric body 135 to completely fill the cavities 135 a , and may be formed in other cavities 135 a to partially fill the cavities 135 a .

[0108] Figure 4 is a cross-sectional view showing a composite piezoelectric element according to a third embodiment of the present invention.

[0109] Hereinafter, among the elements of the composite piezoelectric element 100 ″ according to the third embodiment, the same elements as those of the composite piezoelectric element 100 according to the first embodiment will be omitted or described, as necessary, and the same reference numerals will be given to the same elements as those of the composite piezoelectric element 100 according to the first embodiment.

[0110] The composite piezoelectric element 100 ″ according to the third embodiment differs from the composite piezoelectric element 100 according to the first embodiment in that a metal film 171 is formed in the cavity 135 a of the ultrasound receiving piezoelectric body 135 , and a metal plate 173 covering the cavity 135 a is formed above the ultrasound receiving piezoelectric body 135 .

[0111] At this time, the metal film 171 and the metal plate 173 may be made of a material that can improve ultrasonic receiving efficiency, such as a metal having high acoustic impedance.

[0112] In this way, if the metal film 171 is formed in the cavity 135a of the ultrasonic receiving piezoelectric body 135, and the metal plate 173 is formed to cover the cavity 135a provided with the metal film 171, the ultrasonic wave entering the cavity 135a can be reflected / re-reflected by the metal film 171 and the metal plate 173 in the cavity 135a, and thus maintained in the cavity 135a for a certain period of time, thereby improving the ultrasonic receiving efficiency.

[0113] exist Figure 4 In the embodiment, the metal film 171 is formed in all the cavities 135a of the ultrasound receiving piezoelectric body 35. However, the metal film 171 may be formed only in some of the cavities 135a.

[0114] According to an embodiment, if an element that may serve as the metal plate 173 is disposed above the cavity 135 a of the ultrasound receiving piezoelectric body 135 , the metal plate 173 may be omitted.

[0115] exist Figure 4 In the embodiment, the metal film 171 is formed in all the cavities 135a of the ultrasound receiving piezoelectric body 135. However, the metal film 171 may be formed only in some of the cavities 135a.

[0116] exist Figure 4 In the embodiment, the metal films 171 respectively formed in the cavities 135a of the ultrasound receiving piezoelectric body 135 have the same thickness. However, the metal films 171 respectively formed in the cavities 135a of the ultrasound receiving piezoelectric body 135 may have different thicknesses.

[0117] exist Figure 4 In the embodiment, one metal plate 173 is formed to cover all the cavities 135a. However, a plurality of metal plates 173 may be formed to individually cover the cavities 135a.

[0118] According to an embodiment, the metal film 171 and the metal plate 173 may be formed to correspond to each other. That is, the metal plate 173 may be formed to cover the cavity 135 a where the metal film 171 is provided.

[0119] Figure 5 : is a graph showing a comparison curve of ultrasonic oscillation intensity in an ultrasonic oscillation piezoelectric body provided with a cavity and an ultrasonic oscillation piezoelectric body not provided with a cavity.

[0120] Figure 5 The curve shows the ultrasonic oscillation intensity in an embodiment of an ultrasonic oscillation piezoelectric body provided with a cavity to increase the oscillation intensity of a 10 MHz signal, wherein various frequencies for increasing the oscillation intensity can be determined by structural changes in the cavity formed in the ultrasonic oscillation piezoelectric body.

[0121] For the purpose of experiment, ultrasonic oscillation piezoelectric bodies having the same properties can be used as the ultrasonic oscillation piezoelectric body of the embodiment and the ultrasonic oscillation piezoelectric body of the comparative example, wherein two cavities with a depth of 113 μm are formed in the ultrasonic oscillation piezoelectric body of the embodiment, while no cavity is formed in the ultrasonic oscillation piezoelectric body of the comparative example.

[0122] like Figure 5 As shown, the oscillation intensity of the ultrasonic wave oscillated from the ultrasonic oscillation piezoelectric body provided with the cavity is stronger than the oscillation intensity of the ultrasonic wave oscillated from the ultrasonic oscillation piezoelectric body not provided with the cavity.

[0123] In this way, a cavity can be formed in the ultrasonic oscillation piezoelectric body to enhance the oscillation intensity of the ultrasonic wave oscillated by the ultrasonic oscillation piezoelectric body.

[0124] Figure 6 : is a graph showing a comparison curve of ultrasound receiving sensitivity in an ultrasound receiving piezoelectric body provided with a cavity and an ultrasound receiving piezoelectric body not provided with a cavity.

[0125] Figure 6 The curve shows the ultrasonic receiving sensitivity in an embodiment of an ultrasonic receiving piezoelectric body provided with a cavity to improve the receiving sensitivity of a 10 MHz signal, wherein various frequencies for improving the receiving sensitivity can be determined by structural changes of the cavity formed in the ultrasonic receiving piezoelectric body.

[0126] For experiments, ultrasound receiving piezoelectric bodies having the same properties as the ultrasound receiving piezoelectric body of the embodiment and the ultrasound receiving piezoelectric body of the comparative example may be used, wherein two cavities having a depth of 9 μm are formed in the ultrasound receiving piezoelectric body of the embodiment, while no cavity is formed in the ultrasound receiving piezoelectric body of the comparative example.

[0127] like Figure 6 As shown, the receiving sensitivity of ultrasonic waves received by the ultrasonic receiving piezoelectric body provided with a cavity is higher than the receiving sensitivity of ultrasonic waves received by the ultrasonic receiving piezoelectric body not provided with a cavity.

[0128] In this way, a cavity can be formed in the ultrasound receiving piezoelectric body to improve the reception sensitivity of ultrasonic waves received by the ultrasound receiving piezoelectric body.

[0129] Figure 7 is a block diagram showing an example of an electronic device provided with the composite piezoelectric element of the present disclosure, Figure 8 It shows the settings Figure 7 A cross-sectional view of an example of a composite piezoelectric element.

[0130] The electronic device 700 according to an embodiment of the present disclosure may be, for example, but not limited to, a smartphone, a tablet PC, a mobile phone, a video phone, an e-reader, a desktop PC, a laptop PC, a network computer, a medical device, a camera, or a wearable device.

[0131] Reference Figure 7 and Figure 8 , Figure 7 The electronic device 700 may include a processor 710, a memory 720, a display 730, a touch panel 740, an ultrasonic sensor 750, and a tactile actuator 760, but is not limited thereto. The elements of the electronic device 700 are not limited thereto. Figure 7 embodiments, and at least one of these elements may be omitted or other elements may be additionally provided.

[0132] The processor 710 may include one or more of a central processing unit, an application processor, and a communication processor. For example, the processor 710 may perform calculations or data processing to control at least one other element of the electronic device 700 and / or communicate with at least one other element of the electronic device 700.

[0133] The memory 720 may include volatile and / or nonvolatile memory. For example, the memory 720 may store software and / or programs for executing commands and / or data, operations or functions related to at least one other element of the electronic device 700.

[0134] The display 730 can display various contents (e.g., text, images, videos, icons and / or symbols, etc.), and can be formed by, for example, any one of a liquid crystal display (LCD), a light emitting diode (LED) display, an organic light emitting diode (OLED) display, a microelectromechanical system (MEMS) display, and an electronic paper display, but is not limited thereto.

[0135] The touch panel 740 can identify the touched contact point based on the user's touch input signal (e.g., touch or proximity) and measure the position value of the touch input. The touch panel 740 can be implemented as an add-on type provided on the display 730, or as an on-box type or in-box type inserted into the display 730. The touch panel 740 can be implemented as a resistive type, a capacitive type, an electromagnetic induction type, an optical type, etc.

[0136] The ultrasonic sensor 750 may include an ultrasonic oscillating piezoelectric body and an ultrasonic receiving piezoelectric body. If a voltage is applied to the ultrasonic oscillating piezoelectric body under the control of the processor 710, the ultrasonic oscillating piezoelectric body is used to oscillate ultrasonic waves, and the ultrasonic receiving piezoelectric body is used to receive reflected waves returned from an external object (for example, a user's hand or finger) reflected from the upper surface of the touch display 730, convert the reflected waves into electrical signals and transmit body information corresponding to the external object (for example, finger scan data) to the processor.

[0137] The ultrasonic oscillating piezoelectric body and the ultrasonic receiving piezoelectric body can be reference Figures 1 to 4The ultrasonic oscillating piezoelectric body 133 and the ultrasonic receiving piezoelectric body 135 are described. The ultrasonic sensor 750 can be formed in a specific area (area C) of the composite piezoelectric element 800, such as Figure 8 shown.

[0138] The tactile actuator 760 may be configured to provide tactile feedback (e.g., vibration) to the user according to a signal applied under the control of the processor 710, and the tactile actuator 760 may be formed in a specific region (region B) of the composite piezoelectric element 800, as shown in FIG. Figure 8 shown.

[0139] The speaker actuator 770 may be configured to generate sound according to a signal applied under the control of the processor 710, and may be formed in a specific region (region A) of the composite piezoelectric element 800, such as Figure 8 shown.

[0140] The earpiece actuator 780 may be configured to receive a call according to a signal applied under the control of the processor 710, and may be formed in a specific region (region D) of the composite piezoelectric element 800, as shown in FIG. Figure 8 shown.

[0141] In this way, the ultrasonic sensor 750 , the haptic actuator 760 , the speaker actuator 770 , and the earpiece actuator 780 may be formed in the composite piezoelectric element 800 , whereby one composite piezoelectric element 800 may operate as an actuator for various functions.

[0142] although Figure 8 The composite piezoelectric element 800 is shown to be divided into a plurality of regions (region A, region B, region C, and region D), and each of the ultrasonic sensor 750, the tactile actuator 760, the speaker actuator 770, and the earpiece actuator 780 is formed in one region, but one actuator can be used as shown in FIG. Figures 1 to 4 The various functions described.

[0143] Despite Figure 7 and Figure 8 Although not shown in the figure, membrane-type thin films for protecting and supporting composite piezoelectric element 800 may be arranged on the upper and lower parts of composite piezoelectric element 800 .

[0144] It is obvious to those skilled in the art that the present disclosure is not limited to the above-described embodiments and drawings, and that various substitutions, modifications, and variations may be made to the present disclosure without departing from the spirit or scope of the present disclosure. Therefore, the scope of the present disclosure is defined by the appended claims, and all variations or modifications derived from the meaning, scope, and equivalents of the claims are intended to fall within the scope of the present disclosure.

[0145] The various embodiments described above can be combined to provide additional embodiments. All U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications, and non-patent publications cited in this specification and / or listed in the application data sheet are incorporated herein by reference in their entirety. If necessary, various aspects of the embodiments can be modified to adopt the concepts of the various patents, applications, and publications to provide additional embodiments.

[0146] These and other changes can be made to the embodiments in light of the above detailed description. Generally, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments and the full scope of equivalents of these claims. Therefore, the claims are not limited by this disclosure.

[0147] CROSS-REFERENCE TO RELATED APPLICATIONS

[0148] This application claims the benefit of Korean Patent Application No. 10-2019-0162932, filed on December 9, 2019, which is hereby incorporated by reference as if fully set forth herein.

Claims

1. A composite piezoelectric element, comprising: Insulating films and piezoelectric bodies are arranged alternately. The piezoelectric body is classified into a general piezoelectric body and a finger scan recognition piezoelectric body. The general piezoelectric body is used as at least one of a tactile actuator, a speaker actuator, and an earpiece actuator. The finger scan recognition piezoelectric body is used for finger scan recognition. Wherein, the finger scanning recognition piezoelectric body includes: an ultrasonic oscillation piezoelectric body configured to oscillate ultrasonic waves and having a first cavity; and an ultrasonic receiving piezoelectric body for receiving a reflected signal reflected by the ultrasonic wave oscillating from the ultrasonic oscillation piezoelectric body, the ultrasonic receiving piezoelectric body having a second cavity different from the first cavity, wherein the first cavity is formed in the ultrasonic oscillation piezoelectric body, and the second cavity is formed in the ultrasonic receiving piezoelectric body, wherein the first cavity is formed at a depth at which the frequency of the ultrasonic wave oscillated by the ultrasonic oscillating piezoelectric body resonates, and the second cavity is formed at a depth at which the frequency of the ultrasonic wave received by the ultrasonic receiving piezoelectric body resonates, and The composite piezoelectric element further includes a metal film formed in the second cavity and a metal plate covering the second cavity.

2. The composite piezoelectric element according to claim 1, wherein All of the general piezoelectric bodies are used as one of the haptic actuator, the speaker actuator, and the earpiece actuator.

3. The composite piezoelectric element according to claim 1, wherein: The general piezoelectric bodies are classified into a plurality of groups, and the general piezoelectric bodies included in the respective groups are used as different actuators.

4. The composite piezoelectric element according to claim 1, wherein: Some of the general piezoelectric bodies are used as actuators with one function, while other general piezoelectric bodies are used as actuators with multiple functions.

5. The composite piezoelectric element according to claim 1, wherein The depth of the first cavity and the depth of the second cavity may be the same as or different from each other. The composite piezoelectric element according to claim 1 , wherein: The depths of the first cavities formed in the ultrasonic oscillation piezoelectric body are the same as or different from each other, and the depths of the second cavities formed in the ultrasonic reception piezoelectric body are the same as or different from each other.

7. The composite piezoelectric element according to claim 1, wherein: A polymer material is also formed in at least one of the first cavity and the second cavity.

8. The composite piezoelectric element according to claim 7, wherein: A height of the polymer material formed in the first cavity and a height of the polymer material formed in the second cavity are the same as or different from each other.

9. The composite piezoelectric element according to claim 1, wherein A polymer material is formed in all or some of the first cavities formed in the ultrasonic oscillation piezoelectric body, and a polymer material is formed in all or some of the second cavities formed in the ultrasonic receiving piezoelectric body.

10. The composite piezoelectric element according to claim 9, wherein: Respective heights of the polymer material formed in the first cavity are the same as or different from each other, and respective heights of the polymer material formed in the second cavity are the same as or different from each other.

11. An electronic device, comprising: An ultrasonic sensor, wherein the ultrasonic sensor is used for finger scanning and recognition; as well as at least one or more of a haptic actuator, a speaker actuator, and an earpiece actuator, wherein the ultrasonic sensor and the at least one or more actuators constitute a composite piezoelectric element, The ultrasonic oscillation piezoelectric body and the ultrasonic receiving piezoelectric body constituting the ultrasonic sensor are arranged in the composite piezoelectric element, and a first cavity and a second cavity are formed in the ultrasonic oscillation piezoelectric body and the ultrasonic receiving piezoelectric body respectively. wherein the first cavity is formed at a depth at which the frequency of the ultrasonic wave oscillated by the ultrasonic oscillating piezoelectric body resonates, and the second cavity is formed at a depth at which the frequency of the ultrasonic wave received by the ultrasonic receiving piezoelectric body resonates, and A metal film is further formed in the second cavity, and a metal plate is further formed to cover the second cavity.

12. The electronic device according to claim 11, wherein A polymer material is also formed in at least one of the first cavity and the second cavity.

13. The electronic device according to claim 11, wherein A general piezoelectric body serving as at least one of the haptic actuator, the speaker actuator, and the earpiece actuator is provided in the composite piezoelectric element.

14. The electronic device according to claim 13, wherein: Some of the general piezoelectric bodies are used as actuators with one function, and other general piezoelectric bodies are used as actuators with multiple functions.

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