Haptic actuator with enhanced durability

Abstract

The present invention relates to a haptic actuator. The haptic actuator is proposed in consideration of the problem of performance degradation or physical damage caused by repeated mechanical stress and high vibration frequency in conventional piezoelectric elements. The haptic actuator includes a strength-reinforcing layer, configured to improve strength, on a first surface of a piezoelectric element to which external pressure is applied.

Description

Durable haptic actuator

[0001] The present invention relates to a haptic actuator having a coating layer and a reinforcing plate formed on the surface of a piezoelectric element, and more specifically, to a haptic actuator having a reinforcing coating layer and a reinforcing plate formed on the surface of a piezoelectric element to enhance the durability of a piezoelectric element used in haptic functions such as electric vehicles and mobile phones.

[0002] Piezoelectric materials produce voltage (electric) when pressure (mechanical energy) is applied.

[0003] Mechanical energy is generated (piezoelectric effect), and conversely, when voltage (electrical energy) is applied, an increase or decrease in volume or length due to pressure changes within the piezoelectric material (inverse piezoelectric effect) occurs. In particular, the inverse piezoelectric effect can be applied to realize vibration devices or speakers (sound generation through vibration).

[0004] Recently, the application of haptic technology based on piezoelectric elements is rapidly expanding in the automotive and mobile phone industries.

[0005] Meanwhile, since the piezoelectric elements used in haptics are composed of ceramics, performance degradation or physical damage may occur due to repeated mechanical stress and high vibration frequency, so measures to improve this are required.

[0006] The matters described in the background technology above are intended to aid in understanding the background of the invention and may include matters that are not disclosed prior art.

[0007] The present invention is proposed in consideration of the aforementioned conventional circumstances, and aims to extend the lifespan of a haptic actuator by improving the strength of the piezoelectric element through coating the surface of the piezoelectric element or attaching a structure to the surface.

[0008] A haptic actuator may include a piezoelectric element having a first surface to which external pressure is applied, and a piezoelectric element strength reinforcing layer disposed on the first surface and configured to enhance the strength of the piezoelectric element.

[0009] The piezoelectric element strength reinforcing layer may be a piezoelectric element coating layer formed on the first surface of the piezoelectric element.

[0010] The thickness of the piezoelectric element coating layer may be 10 μm or more and 50 μm or less.

[0011] The haptic actuator can be improved by 15% to 25% compared to the strength of the piezoelectric element.

[0012] The piezoelectric element coating layer can be formed by at least one of the printing method, the spray method, and the dipping method.

[0013] The piezoelectric element strength reinforcing layer is a piezoelectric element reinforcing plate formed on the surface of the first surface of the piezoelectric element, and the area of ​​the lower surface of the piezoelectric element reinforcing plate facing the first surface may be the same as the area of ​​the first surface.

[0014] The piezoelectric element strength reinforcing layer is a piezoelectric element reinforcing plate formed on the surface of the first surface of the piezoelectric element, and the area of ​​the lower surface of the piezoelectric element reinforcing plate facing the first surface may be larger than the area of ​​the first surface.

[0015] A haptic actuator in which the width of the lower surface of the piezoelectric element reinforcing plate in the first direction is the same as the width of the first surface in the first direction, and the width of the lower surface of the piezoelectric element reinforcing plate in the second direction is larger than the width of the first surface in the second direction.

[0016] The lower surface of the piezoelectric element reinforcing plate can be formed with an area greater than 100% and less than or equal to 200% of the area of ​​the first surface.

[0017] The piezoelectric element reinforcing plate may be composed of at least one material among stainless steel, beryllium copper, and titanium.

[0018] An electrode is exposed on the first surface of the piezoelectric element, and a piezoelectric element strength reinforcing layer can be placed on the surface of the electrode.

[0019] According to the present invention, when the surface of a bimorph piezoelectric ceramic element applied to a component supporting haptic functions of an electric vehicle and a mobile phone is coated or a structure is attached to the surface, the strength of the ceramic element is improved, thereby preventing performance degradation or physical damage caused by repeated mechanical stress and high vibration frequency.

[0020] In addition, due to the wider structure compared to the piezoelectric element attached to the ceramic surface, the principle of leverage is applied, allowing stronger pressure to be transmitted with less force. Furthermore, because the haptic vibration effect also occurs over a wider range due to the wider structure, it can be manufactured in a smaller size than conventional piezoelectric elements, thereby reducing process costs.

[0021] FIG. 1 is a conceptual diagram of a piezoelectric element according to one embodiment of the present invention.

[0022] FIG. 2 is a conceptual diagram of a piezoelectric layer having an internal electrode formed (arranged) according to one embodiment of the present invention.

[0023] FIG. 3 is a conceptual diagram of an external electrode formed on the outside of a piezoelectric element according to one embodiment of the present invention.

[0024] FIG. 4 is a conceptual diagram of a haptic actuator according to one embodiment of the present invention.

[0025] FIG. 5 is a conceptual diagram of a haptic actuator according to one embodiment of the present invention.

[0026] Figure 6 is a conceptual diagram of the haptic actuator illustrated in Figure 5.

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0028] The embodiments are provided to more fully explain the invention to those skilled in the art, and the following embodiments may be modified in various different forms, and the scope of the invention is not limited to the following embodiments. Rather, these embodiments are provided to make the disclosure more faithful and complete and to fully convey the spirit of the invention.

[0029] The terms used herein are for describing specific embodiments and are not intended to limit the invention. Additionally, the singular form in this specification may include the plural form unless the context clearly indicates otherwise. Terms such as “comprising,” “having,” and “having” in this application are intended to specify the presence of features, numbers, steps, actions, components, parts, or combinations thereof of the invention, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0030] In the description of the embodiments, where each layer (film), region, pattern, or structure is described as being formed "on" or "under" the substrate, each layer (film), region, pad, or pattern, "on" and "under" include both being formed "directly" and "indirectly" through another layer. In addition, the reference for the top or bottom of each layer is, in principle, based on the drawings.

[0031] The drawings are intended solely to facilitate an understanding of the concept of the present invention and should not be interpreted as limiting the scope of the invention. Additionally, relative thicknesses, lengths, or sizes in the drawings may be exaggerated for convenience and clarity of explanation.

[0032] The piezoelectric element coating layer (140) and the piezoelectric element reinforcing plate (150) formed on the piezoelectric element (100) according to one embodiment of the present invention can be applied to piezoelectric haptic products for electric vehicles and mobile phones, and can be applied to piezoelectric elements in various fields such as mobile phone side key haptics, ultra-long distance ultrasonic sensors, actuators for 3D haptics, and directional speakers.

[0033] According to one embodiment of the present invention, the piezoelectric element coating layer (140) and the piezoelectric element reinforcing plate (150) are included in the piezoelectric element reinforcing layer.

[0034] The upper surface of the piezoelectric element (100) according to one embodiment of the present invention may be a first surface to which external pressure is applied.

[0035] A haptic actuator (10) according to one embodiment of the present invention includes a piezoelectric element (100) and a piezoelectric element coating layer (140), and the piezoelectric element coating layer (140) may be formed on the upper surface (or a first surface to which external pressure is applied) of the piezoelectric element (100) facing the haptic frame (160).

[0036] A haptic actuator (10-1) according to one embodiment of the present invention includes a piezoelectric element (100) and a piezoelectric element reinforcing plate (150), and the piezoelectric element reinforcing plate (150) may be formed on the upper surface (a first surface to which external pressure is applied) of the piezoelectric element (100) facing the haptic frame (160).

[0037] A piezoelectric element (100) can be formed on a substrate (200), and a haptic frame (160) can be connected to a device frame (300). The substrate (200) can be a substrate used in electric vehicles and mobile phones, such as a Flexible Printed Circuit (FPC) or a Printed Circuit Board (PCB).

[0038] The device frame (300) may be a frame of a mobile phone device.

[0039] As illustrated in FIGS. 4 and 5, the haptic frame (160) is shown in a protruding form, but it can be formed in a smooth form similar to the device frame (300), or conversely, in a recessed form. Accordingly, the configurations of the haptic actuators (10, 10-1) can be positioned or sized to correspond to the corresponding positions.

[0040] A haptic frame (160) may be placed on the outside of a piezoelectric element (100). The haptic frame (160) may be a frame connected to the frame of a vehicle and a mobile phone. The haptic frame (160) may include a configuration such as a physical button used in a vehicle and a mobile phone.

[0041] The piezoelectric element coating layer (140) and the piezoelectric element reinforcing plate (150) are placed on the upper surface of the piezoelectric element (100) and can serve to improve the strength of the piezoelectric element (100).

[0042] A piezoelectric element coating layer (140) and a piezoelectric element reinforcing plate (150) formed on a piezoelectric element (100) according to one embodiment of the present invention may be formed by overlapping. For example, a piezoelectric element coating layer (140) may be formed on the upper surface of the piezoelectric element (100), and a piezoelectric element reinforcing plate (150) may be formed on the upper surface of the piezoelectric element coating layer (140).

[0043] A piezoelectric element (100) according to one embodiment of the present invention may be a piezoelectric element including a piezoelectric haptic function.

[0044] A piezoelectric element (100) according to one embodiment of the present invention may be formed in a multilayer structure, and various types of piezoelectric elements such as bimorph and unimorph may be applied. For example, it may be formed in an 11+11 layer bimorph structure.

[0045] A piezoelectric element (100) according to one embodiment of the present invention may include piezoelectric ceramic powder.

[0046] The piezoelectric ceramic powder may include at least one of PMN-based ceramics, PNN-based ceramics, PNN-PZT-based ceramics, and PMN-PNN-PZT ceramics, but the composition is not limited to the said ceramics.

[0047] In all drawings except Fig. 3, the shapes of the external electrodes (121, 122, 123, 124) are omitted.

[0048] FIG. 1 is a conceptual diagram of a piezoelectric element according to one embodiment of the present invention. FIG. 2 is a conceptual diagram of a piezoelectric layer having an internal electrode formed (arranged) according to one embodiment of the present invention. FIG. 3 is a conceptual diagram of an external electrode formed on the outside of a piezoelectric element according to one embodiment of the present invention.

[0049] Referring to FIGS. 1 to 3, the piezoelectric element (100) may be composed of an internal electrode, an external electrode, and a piezoelectric layer (130).

[0050] The internal electrode may be composed of a first internal electrode (111), a second internal electrode (112), a third internal electrode (113), and a fourth internal electrode (114).

[0051] The external electrode may be composed of a first external electrode (121), a second external electrode (122), a third external electrode (123), and a fourth external electrode (124).

[0052] The piezoelectric layer (130) may be composed of a first piezoelectric layer (131) and a second piezoelectric layer (132).

[0053] Internal electrodes are formed on one or both sides of the piezoelectric layer (130).

[0054] For example, a first internal electrode (111) and a second internal electrode (112) are formed on one or both sides of the first piezoelectric layer (131).

[0055] A third internal electrode (113) and a fourth internal electrode (114) are formed on one or both sides of the second piezoelectric layer (132).

[0056] The internal electrode and the external electrode can be composed of various printing electrodes containing conductors such as Ag, Au, Pt, Pd, Cu, Ni, etc.

[0057] The first internal electrode (111) extends in the opposite direction to the second internal electrode (112). The third internal electrode (113) extends in the opposite direction to the fourth internal electrode (114).

[0058] The external electrode can be electrically connected to the internal electrode in the form of a termination. Additionally, vias of a predetermined diameter can be formed in the piezoelectric element (100) or the piezoelectric layer (130), and a conductive material can be filled inside the vias. As a result, the internal and external electrodes (110, 120) can be electrically connected to each other.

[0059] The first internal electrode (111) can be electrically connected to the first external electrode (121), the second internal electrode (112) can be electrically connected to the second external electrode (122), the third internal electrode (113) can be connected to the third external electrode (123), and the fourth internal electrode (114) can be electrically connected to the fourth external electrode (124).

[0060] The piezoelectric layer (130) can be formed into a thin single-layer film by performing a polishing process on a thick-film type piezoelectric ceramic.

[0061] The piezoelectric layer (130) includes a form in which the first piezoelectric layer (131) and the second piezoelectric layer (132) are sequentially stacked.

[0062] The piezoelectric layer (130) may include piezoelectric ceramic powder (133), such as PNN-PZT ceramic, PMN ceramic, PNN ceramic, and PMN-PNN-PZT ceramic.

[0063] Additionally, the piezoelectric layer (130) may include not only polycrystalline ceramics such as PZT, but also single-crystal piezoelectric materials such as PMN-PT, PZN-PT, PIN-PT, and PYN-PT, flexible piezoelectric polymer materials such as PVDF and PVDF-TrFE, and lead-free piezoelectric novel materials such as BNT (BaNiTiO3) and BZT-BCT.

[0064] Meanwhile, FIG. 2 according to one embodiment of the present invention is a drawing in which the shape of the electrodes (111, 112, 113, 114) formed in FIG. 1 is omitted, in the form of the electrodes (111, 112, 113, 114) formed by extending from the side to the center of the piezoelectric layer (130) and intersecting as in FIG. 1.

[0065] The external electrodes (121, 122, 123, 124) shown in FIG. 3 are a form for representing the external electrodes and can be formed with almost no thickness, unlike as shown.

[0066] Although not shown, a piezoelectric element reinforcing layer may be formed on the upper surface of the piezoelectric element (100) of FIGS. 1 to 3.

[0067] FIG. 4 is a conceptual diagram of a haptic actuator (10) according to one embodiment of the present invention.

[0068] Referring to FIG. 4, a haptic actuator (10) according to one embodiment of the present invention may be composed of a piezoelectric element (100), a piezoelectric element coating layer (140), and a haptic frame (160).

[0069] A haptic actuator (10) according to one embodiment of the present invention includes a piezoelectric element (100) disposed inside the haptic actuator (10) and a haptic frame (160) disposed outside the piezoelectric element (100), and a piezoelectric element coating layer (140) may be formed on the upper surface of the piezoelectric element (100) facing the haptic frame (160).

[0070] The piezoelectric element coating layer (140) serves to cushion the impact received by the ceramic of the piezoelectric element (100) from continuous or strong external pressure (e.g., pressure from the device frame 160), and is a coating layer to prevent cracks or malfunctions from occurring in the piezoelectric element (100).

[0071] A haptic actuator (10) according to one embodiment of the present invention may have a space formed between the piezoelectric element (100), the piezoelectric element coating layer (140), and the haptic frame (160) as shown in FIG. 4, or may have almost no space between them or be formed in a form that is in close contact with each other.

[0072] A piezoelectric element (100) can be formed on a substrate (200), and a haptic frame (160) can be connected to a device frame (300). The substrate (200) can be a substrate used in electric vehicles and mobile phones, such as a Flexible Printed Circuit (FPC) or a Printed Circuit Board (PCB).

[0073] The piezoelectric element coating layer (140) may be formed on the upper surface of the piezoelectric element (100) facing the haptic frame (160). Additionally, when the piezoelectric element coating layer (140) is formed on the upper surface, it directly protects the piezoelectric element (100), thereby making the cushioning action more effective.

[0074] However, the piezoelectric element coating layer (140) may be formed on the lower surface of the haptic frame (160) facing the piezoelectric element (100) according to the manufacturer's intention. If the piezoelectric element coating layer (140) is formed on the lower surface, only the piezoelectric element (100) needs to be replaced in the event of a failure of the piezoelectric element (100), thus reducing costs.

[0075] In addition, the upper and lower surfaces may be formed simultaneously, in which case the buffering action on the piezoelectric element (100) can be performed more stably.

[0076] A haptic actuator (10) according to one embodiment of the present invention may have a space formed between the piezoelectric element (100), the piezoelectric element coating layer (140), and the haptic frame (160) as shown in FIG. 4, or may have almost no space between them or be formed in a form that is in close contact with each other.

[0077] The piezoelectric element coating layer (140) can be formed with a thickness of 10 μm or more and 50 μm or less. The piezoelectric element (100) having the piezoelectric element coating layer (140) formed thereon can be formed with a thickness of 0.7 T (thickness 0.7 mm) or less. (1 T = 1 mm thickness)

[0078] The piezoelectric element coating layer (140) can be formed from a liquid-type material. The piezoelectric element coating layer (140) can be formed from an epoxy material.

[0079] When the surface of the piezoelectric element is coated with a piezoelectric element coating layer (140), the strength of the piezoelectric element (100) can be improved by 15% to 25%.

[0080] The coating method of the piezoelectric element coating layer (140) may include at least one of a printing method, a spray method, and a dipping method.

[0081] The piezoelectric element coating layer (140) can be formed on the top of the piezoelectric element (100) instead of the ceramic layer. As a result, the piezoelectric element coating layer (140) can simultaneously serve as both the ceramic layer and the protective layer. Furthermore, there is no need to reduce the thickness of the piezoelectric element (100) to secure space for the piezoelectric element coating layer (140), so there is no significant impact on the performance degradation of the haptic actuator (10), and there is an advantage of being able to reduce costs.

[0082] In addition, by positioning the piezoelectric element coating layer (140) on the upper surface, discoloration caused by oxidation of the exposed metal electrode (internal electrode of the piezoelectric element) can be prevented without separately forming a ceramic layer at the top. The internal electrode of the piezoelectric element (100) can be formed of Ag metal material.

[0083] For example, the thickness of the top ceramic layer can be formed to be 0.05T to 0.15T, 0.1T to 0.2T, 0.05T to 0.2T, and 0.05T or less. Additionally, the thickness of the top ceramic layer can be formed to be thinner than the thickness of the piezoelectric element coating layer (140). This allows the strength to be improved without increasing the thickness of the existing piezoelectric element (100).

[0084] Meanwhile, the piezoelectric element coating layer (140) can be composed of multiple layers. If the coating layer is composed of a liquid material such as a paste material or an epoxy material, it has the advantage of being easily laminated, allowing for fine height adjustment.

[0085] In addition, the cushioning effect and strength can be enhanced by applying coating layers of different materials. For example, when composed of three layers, if a coating layer of high strength is placed on the first and third layers and a coating layer of high cushioning effect is placed on the second layer, there is an advantage of obtaining both strength and cushioning effect. For example, epoxy, polyurethane, polyimide, and ceramic coating agents can be used as high-strength coating agents, while silicone, rubber-based materials, and polyurethane can be used as coating agents with high cushioning effect.

[0086] FIG. 5 is a conceptual diagram of a haptic actuator (10-1) according to one embodiment of the present invention.

[0087] Referring to FIG. 5, a haptic actuator (10-1) according to one embodiment of the present invention may be composed of a piezoelectric element (100), a piezoelectric element reinforcing plate (150), and a haptic frame (160).

[0088] A haptic actuator (10-1) includes a piezoelectric element (100) disposed inside the haptic actuator (10-1) and a haptic frame (160) disposed outside the piezoelectric element (100), and a piezoelectric element reinforcing plate (150) may be formed on the upper surface of the piezoelectric element (100) facing the haptic frame (160). Since the piezoelectric element reinforcing plate (150) is formed on the upper surface and directly protects the piezoelectric element (100), it can provide an effective cushioning action.

[0089] The piezoelectric element reinforcing plate (150) serves to cushion the impact received by the ceramic of the piezoelectric element (100) from continuous or strong external pressure (e.g., pressure from the device frame 160), and is a reinforcing plate to prevent cracks or malfunctions in the piezoelectric element (100).

[0090] The piezoelectric element reinforcing plate (150) can be formed into a plate-like structure.

[0091] A piezoelectric element (100) can be formed on a substrate (200), and a haptic frame (160) can be connected to a device frame (300). The substrate (200) can be a substrate used in electric vehicles and mobile phones, such as a Flexible Printed Circuit (FPC) or a Printed Circuit Board (PCB).

[0092] In one embodiment of the present invention, a haptic actuator (10-1) may have a space formed between the piezoelectric element (100), the piezoelectric element reinforcing plate (150), and the haptic frame (160) as shown in FIG. 5, or the space may be almost non-existent or formed in a form that is in close contact with each other.

[0093] In addition, since the piezoelectric element reinforcing plate (150) is formed to be wider than the piezoelectric element (100), when pressure is applied to the side portion of the haptic frame (160), the principle of leverage acts on the piezoelectric element reinforcing plate (150), so there is an advantage that stronger pressure can be applied to the piezoelectric element (100) with less force.

[0094] In addition, since the width of the piezoelectric element reinforcing plate (150) is widened, there is an advantage that the haptic vibration of the piezoelectric element (100) is transmitted over a wider range.

[0095] Meanwhile, the piezoelectric element reinforcing plate (150) may be formed to have an area equal to the upper surface area of ​​the piezoelectric element (100), or to have an area or width of 100% to 200% or 100% to 300% of the upper surface area or width, and preferably to have an area or width of 100% to 150%. However, the description of the present invention is not limited to the above range and may deviate from such range as necessary, and the scope of protection is determined by the claims. (The width of the piezoelectric element reinforcing plate 150 may be formed based on the area where the haptic frame 160 and the piezoelectric element 100 come into contact.)

[0096] The piezoelectric element reinforcing plate (150) can be placed on the top of the piezoelectric element (100) instead of the ceramic layer (i.e., the internal electrode of the piezoelectric element is exposed to the outside and placed on the surface). As a result, the piezoelectric element reinforcing plate (150) can simultaneously serve as both the ceramic layer and the protective layer. Furthermore, there is no need to reduce the thickness of the piezoelectric element (100) to secure space for the piezoelectric element reinforcing plate (150), so it does not significantly affect the performance degradation of the haptic actuator (10-1) and has the advantage of reducing costs.

[0097] In addition, the top ceramic layer can be formed as thin as possible, and a piezoelectric element reinforcing plate can be placed on the upper surface of the top ceramic layer. This allows for cost reduction.

[0098] For example, when the top ceramic layer is formed, the thickness of the top ceramic layer can be formed to be 0.05T to 0.15T, 0.1T to 0.2T, 0.05T to 0.2T, and 0.05T or less. Additionally, the thickness of the top ceramic layer can be formed to be thinner than the thickness of the piezoelectric element reinforcing plate (150). This allows for the strength to be improved without increasing the thickness of the existing piezoelectric element (100), and the internal electrode can be configured so that it is not exposed.

[0099] In addition, by positioning the piezoelectric element reinforcing plate (150) on the upper surface of the piezoelectric element instead of the uppermost ceramic layer, discoloration caused by oxidation of the exposed metal electrode (internal electrode of the piezoelectric element) can be prevented without separately forming the ceramic layer at the top. The internal electrode of the piezoelectric element (100) can be formed of Ag metal material.

[0100] Meanwhile, depending on the manufacturer's intent, an adhesive film may be added between the piezoelectric element reinforcing plate (150) and the metal electrode, thereby improving the fixing force of the piezoelectric element reinforcing plate (150).

[0101] The piezoelectric element reinforcing plate (150) may be formed from at least one material among metals, films, and polymer structures. For example, metals may include SUS (Steel Use Stainless), beryllium copper, titanium, etc. Films may include PET, PI, PC, etc., but are not limited to these, and preferably may be formed from beryllium or titanium.

[0102] The thickness of the piezoelectric element reinforcing plate (150) can be formed to be 0.05T to 0.15T, 0.1T to 0.2T, or 0.05T to 0.2T, and preferably can be formed to a thickness of 0.1T. (1T = 1mm thickness)

[0103] Figure 6 is a conceptual diagram of the haptic actuator illustrated in Figure 5.

[0104] Referring to FIG. 6, FIG. 6 is a conceptual diagram of a piezoelectric element (100) in which a haptic actuator (10-1) shown in FIG. 5, i.e., a piezoelectric element reinforcing plate (150) is placed, viewed from the lower surface of the piezoelectric element (the surface opposite to the first surface of the piezoelectric element).

[0105] The first and second directions disclosed in the claim are, based on FIG. 6, that the first direction is the vertical direction and the second direction is the horizontal direction.

[0106] Referring to FIG. 6, the width of the piezoelectric element reinforcing plate (150) is shown to be larger than that of the piezoelectric element (100) based on the drawing. This is intended to show that the width of the piezoelectric element reinforcing plate (150) is formed wider than that of the piezoelectric element (100), and is not limited to the shape shown in the drawing.

[0107] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to explain, not limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention.

[0108] Although various embodiments have been described above, it should be understood that various modifications are possible. For example, suitable results may be achieved even if the described techniques are performed in a different order, and / or the elements of the described system, structure, device, circuit, etc. are combined in a different way, or are replaced or supplemented by other elements or equivalents. Accordingly, other embodiments fall within the scope of the claims set forth below.

Claims

1. A piezoelectric element having a first surface to which external pressure is applied; and A piezoelectric element strength reinforcing layer disposed on the first surface and configured to improve the strength of the piezoelectric element; comprising Haptic actuator.

2. In Paragraph 1, The above piezoelectric element strength reinforcing layer is, A piezoelectric element coating layer formed on the first surface of the above piezoelectric element, Haptic actuator.

3. In Paragraph 2, The thickness of the piezoelectric element coating layer is 10 μm or more and 50 μm or less, Haptic actuator.

4. In Paragraph 2, The above haptic actuator improves the intensity of the piezoelectric element by 15% to 25%. Haptic actuator.

5. In Paragraph 2, The above piezoelectric element coating layer is, Formed by at least one of a printing method, a spray method, and a dipping method, Haptic actuator.

6. In Paragraph 1, The above piezoelectric element strength reinforcing layer is a piezoelectric element reinforcing plate formed on the surface of the first surface of the above piezoelectric element, and The area of ​​the lower surface of the piezoelectric element reinforcing plate facing the first surface is the same as the area of ​​the first surface. Haptic actuator.

7. In Paragraph 1, The above piezoelectric element strength reinforcing layer is a piezoelectric element reinforcing plate formed on the surface of the first surface of the above piezoelectric element, and The area of ​​the lower surface of the piezoelectric element reinforcing plate facing the first surface is larger than the area of ​​the first surface. Haptic actuator.

8. In Paragraph 7, The width of the first direction of the lower surface of the above-mentioned piezoelectric element reinforcing plate is the same as the width of the first direction of the above-mentioned first surface, and A haptic actuator in which the second direction width of the lower surface of the piezoelectric element reinforcing plate is larger than the second direction width of the first surface.

9. In Paragraph 8, The lower surface of the above-mentioned piezoelectric element reinforcing plate is formed with an area greater than 100% and less than or equal to 200% of the area of ​​the above-mentioned first surface, Haptic actuator.

10. In Paragraph 6, The above piezoelectric element reinforcing plate is composed of at least one material selected from stainless steel, beryllium copper, and titanium. Haptic actuator.

11. In Paragraph 1, An electrode is exposed on the first surface of the above-mentioned piezoelectric element, and The strength reinforcing layer of the piezoelectric element is disposed on the surface of the electrode. Haptic actuator.

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