Display device

Abstract

A display device is provided. The display device includes: a display panel; a main vibrator disposed on the display panel and configured to generate a main vibration wave; and a plurality of sub-vibrators disposed on the display panel and separated from the main vibrator, and the plurality of sub-vibrators are configured to generate sub-vibration waves respectively, wherein the plurality of sub-vibrators include: a first sub-vibrator disposed at a first distance from the main vibrator in a plan view, the first sub-vibrator being configured to generate a first sub-vibration wave; and a second sub-vibrator disposed at a second distance from the main vibrator in a plan view, the second sub-vibrator being configured to generate a second sub-vibration wave having a different phase from the first sub-vibration wave, wherein the second distance is different from the first distance.

Description

[0001] This application claims the priority and benefit of Korean Patent Application No. 10-2019-0097421, filed on Aug. 9, 2019, which is incorporated herein by reference for all purposes as if fully set forth herein. Technical Field

[0002] Exemplary embodiments of the invention generally relate to a display device, and more particularly, to a display device having precise vibration control. Background Art

[0003] Electronic devices that provide images to users, such as smart phones, tablet PCs, digital cameras, laptop computers, vehicle navigation devices, and smart TVs, include display devices for displaying images. The display device includes a display panel for generating and displaying an image and various input devices.

[0004] Display devices have been developed to provide various physical user interfaces (UIs), such as visual interfaces, auditory interfaces, and tactile interfaces, as feedback in response to a touch. Among them, haptic feedback, as a haptic feedback method, is a method of outputting a physical force to a user based on events or interactions occurring in various graphic environments. When a touch is detected by the display device, vibration is applied to the user to convey a tactile sensation.

[0005] The display device may include a vibrator to provide haptic feedback. However, it is difficult to provide precise haptic feedback when the vibration of the vibrator is insufficient or when the vibration occurs in an area other than the touch area.

[0006] The above information disclosed in this background art section is only for understanding the background art of the inventive concept, and thus, it may include information that does not constitute the prior art. Summary of the Invention

[0007] An apparatus constructed according to an exemplary embodiment of the invention provides a display device capable of performing precise vibration control.

[0008] Additional features of the inventive concept will be set forth in the description below, and the additional features of the inventive concept will become partially apparent from the description or may be learned by practicing the inventive concept.

[0009] According to one or more embodiments of the invention, a display device includes a display panel; a main vibrator disposed on the display panel and configured to generate a main vibration wave; and a plurality of sub-vibrators disposed on the display panel and separated from the main vibrator, and the plurality of sub-vibrators are configured to generate sub-vibration waves respectively, wherein the plurality of sub-vibrators include a first sub-vibrator disposed at a first distance from the main vibrator in a plan view, the first sub-vibrator is configured to generate a first sub-vibration wave; and a second sub-vibrator disposed at a second distance from the main vibrator in a plan view, the second sub-vibrator is configured to generate a second sub-vibration wave having a phase different from that of the first sub-vibration wave, wherein the second distance is different from the first distance.

[0010] The phase of the main vibration wave may be different from the phases of the first sub-vibration wave and the second sub-vibration wave.

[0011] The main vibration wave, the first sub-vibration wave, and the second sub-vibration wave may have the same wavelength.

[0012] The difference (Δθ 1 ) between the phase of the first sub-vibration wave and the phase of the main vibration wave may satisfy the following Equation 1: Δθ 1 = 180°×n - (360°×d1) / λ, and the difference (Δθ 2 ) between the phase of the second sub-vibration wave and the phase of the main vibration wave may satisfy the following Equation 2: Δθ 2 = 180°×n - (360°×d2) / λ, where n is an integer, d1 is the first distance between the main vibrator and the first sub-vibrator, d2 is the second distance between the main vibrator and the second sub-vibrator, and λ is the wavelength of the main vibration wave, the first sub-vibration wave, and the second sub-vibration wave.

[0013] Each of the first distance and the second distance may be smaller than half of the wavelength.

[0014] The difference between the phase of the first sub-vibration wave and the phase of the main vibration wave may be greater than 0° and less than 180°, and the difference between the phase of the second sub-vibration wave and the phase of the main vibration wave may be greater than 0° and less than 180°.

[0015] The first sub-vibration wave and the second sub-vibration wave may be configured to destructively interfere with the main vibration wave.

[0016] The display device may further include: a phase controller configured to control the phases of the AC voltages supplied to each of the first sub-vibrator and the second sub-vibrator and the main vibrator.

[0017] The maximum amplitude of the first main vibrator may be greater than the maximum amplitude of the first sub-vibrator or the maximum amplitude of the second sub-vibrator.

[0018] A plurality of sub-vibrators can at least partially surround the main vibrator.

[0019] The main vibrator can be disposed in a central region of the display panel in a plan view, and the plurality of sub-vibrators can be disposed along an edge of the display panel in the plan view.

[0020] The display device can further include a cover panel stacked with the display panel. The display panel can include a display surface and an opposite surface opposite to the display surface. The cover panel can be disposed on the opposite surface of the display panel, and the main vibrator and the sub-vibrators can be attached to the cover panel.

[0021] The display device can further include a touch member disposed on the display surface of the display panel.

[0022] Each of the main vibrator and the sub-vibrators can include at least one of a piezoelectric element and an actuator.

[0023] The main vibrator can include a first main vibrator and a second main vibrator separated from each other in a plan view.

[0024] The plurality of sub-vibrators can surround the first main vibrator and the second main vibrator in a plan view.

[0025] In the plan view, the sub-vibrators can not be disposed between the first main vibrator and the second main vibrator.

[0026] The first main vibrator can be configured to generate a first main vibration wave during a first driving mode, and the second main vibrator can be configured to generate a vibration wave to cancel the first main vibration wave during the first driving mode.

[0027] The first main vibrator can be configured to generate a first main vibration wave during a second driving mode, and the second main vibrator can be configured to generate a second main vibration wave that undergoes constructive interference with the first main vibration wave during the second driving mode.

[0028] According to one or more embodiments of the invention, a display device includes: a display panel; a first vibrator disposed on the display panel; and a second vibrator disposed on the display panel and separated from the first vibrator. A difference (Δθ) between a phase of a vibration wave of the second vibrator and a phase of a vibration wave of the first vibrator satisfies the following equation: Δθ = 180°×n - (360°×d) / λ, where n is an integer, d is a distance between the first vibrator and the second vibrator, and λ is a wavelength of the vibration wave of the first vibrator and the vibration wave of the second vibrator.

[0029] According to a display device according to an exemplary embodiment, vibration waves generated by each vibrator effectively interfere according to the spacing distances of the plurality of vibrators, so that precise vibration control can be performed. Accordingly, precise haptic operations or sound control can be performed by using the plurality of vibrators.

[0030] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the claimed invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the invention and, together with the description, serve to explain the inventive concept.

[0032] Figure 1 is a perspective view of a display device according to an exemplary embodiment.

[0033] Figure 2 is Figure 1 a cross-sectional view of the display device.

[0034] Figure 3 is a layout diagram of a cover panel and vibrators according to an exemplary embodiment.

[0035] Figure 4 is a cross-sectional view of a piezoelectric element according to an exemplary embodiment.

[0036] Figure 5 is a conceptual diagram for explaining the operating characteristics of the piezoelectric element.

[0037] Figure 6 is an exploded perspective view of an actuator according to an exemplary embodiment.

[0038] Figure 7 is a perspective view of an actuator according to another exemplary embodiment.

[0039] Figure 8 is a graph showing the relationship between the amplitude of the vibration wave of one vibrator and the distance.

[0040] Figure 9 is a graph showing the vibration waveform in a medium at a certain distance over time when the vibrator operates.

[0041] Figure 10 and Figure 11 is a graph showing the superimposed waveform of the vibration waves of two vibrators according to the phase difference.

[0042] Figure 12 is a schematic diagram showing the arrangement of a main vibrator and a sub-vibrator according to an exemplary embodiment and their vibration waves.

[0043] Figure 13 It is a graph showing the vibration intensity (or displacement) of a vibration wave according to distance.

[0044] Figure 14 It is a graph showing the relationship between the gravitational equivalence (G) value and the phase difference.

[0045] Figure 15 It is a graph showing the relationship between the log(G) value and the phase difference.

[0046] Figure 16 It is a graph showing the relationship between the decibel level and the phase difference.

[0047] Figure 17 It is a layout diagram of a cover panel and a vibrator according to another exemplary embodiment.

[0048] Figure 18 It is a layout diagram of a cover panel and a vibrator according to yet another exemplary embodiment.

[0049] Figure 19 It is a layout diagram of a cover panel and a vibrator according to yet another exemplary embodiment.

[0050] Figure 20 It is a layout diagram of a cover panel and a vibrator according to yet another exemplary embodiment.

[0051] Figure 21 It is a layout diagram of a cover panel and a vibrator according to yet another exemplary embodiment.

[0052] Figure 22 It is a layout diagram of a cover panel and a vibrator according to yet another exemplary embodiment.

[0053] Figure 23 It is a table showing a method for providing a haptic interface of a display device according to an exemplary embodiment.

[0054] Figure 24 It shows a Figure 23 graph of an application execution screen of a display device provided with a haptic interface. Detailed Description

[0055] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the various exemplary embodiments or implementations of the invention. As used herein, "embodiment" and "implementation" are interchangeable terms that are non-limiting examples of a device or method that employs one or more of the inventive concepts disclosed herein. However, it is apparent that the various exemplary embodiments may be practiced without these specific details or with one or more equivalent arrangements. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the various exemplary embodiments. Additionally, the various exemplary embodiments may be different, but not necessarily exclusive. For example, without departing from the inventive concept, the specific shapes, configurations, and characteristics of an exemplary embodiment may be used or implemented in another exemplary embodiment.

[0056] Unless otherwise stated, the exemplary embodiments shown are to be understood as providing exemplary features of variations in some ways in which the inventive concept may be actually implemented. Thus, unless otherwise stated, the features, components, modules, layers, films, panels, regions, and / or aspects, etc. (hereinafter individually or collectively referred to as "elements" or "a plurality of elements") of each embodiment may be additionally combined, separated, interchanged, and / or rearranged without departing from the inventive concept.

[0057] The use of cross-hatching and / or shading is generally provided in the drawings to clarify the boundaries between adjacent elements. Thus, unless stated otherwise, the presence or absence of cross-hatching or shading does not express or imply any preference or requirement regarding the specific materials, material properties, dimensions, proportions, commonality between the elements shown, and / or any other characteristics, attributes, properties, etc. of the elements. Additionally, in the drawings, for clarity and / or descriptive purposes, the sizes and relative sizes of the elements may be exaggerated. When the exemplary embodiments may be implemented differently, the specific process orders may be performed in a different order than that described. For example, two consecutively described processes may be performed substantially simultaneously or in an order opposite to that described. Additionally, the same reference numerals denote the same elements.

[0058] When an element or layer is referred to as being "on", "connected to", or "coupled to" another element or layer, it can be directly on, directly connected to, or directly coupled to the other element or layer, or intervening elements or layers may be present. However, when an element or layer is referred to as being "directly on", "directly connected to", or "directly coupled to" another element or layer, no intervening elements or layers are present. For this reason, the term "connected" can refer to physical, electrical, and / or fluid connections with or without intervening elements. Additionally, the D1 axis, D2 axis, and D3 axis are not limited to the three axes such as the x-axis, y-axis, and z-axis of a rectangular coordinate system and can be interpreted in a broader sense. For example, the D1 axis, D2 axis, and D3 axis can be perpendicular to each other or can represent different directions that are not perpendicular to each other. For the purposes of this disclosure, "at least one of X, Y, and Z" and "at least one selected from the group consisting of X, Y, and Z" can be interpreted as only X, only Y, only Z, or any combination of two or more of X, Y, and Z, such as by way of example XYZ, XYY, YZ, and ZZ. As used herein, the term "and / or" includes any combination and all combinations of one or more of the associated listed items.

[0059] Although terms such as "first", "second", etc. may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. Thus, a first element discussed below may be referred to as a second element without departing from the teachings of the disclosure.

[0060] For descriptive purposes, spatial terms such as "beneath", "below", "under", "lower", "above", "upper", "on top of", "higher", and "side" (e.g., as in "sidewall") may be used herein to describe the relationship of one element to another as shown in the figures. In addition to the orientation depicted in the figures, the spatial relative terms are intended to include different orientations of the device in use, operation, and / or manufacture. For example, if the device in the figures is flipped over, an element described as "beneath" or "below" another element or feature will then be positioned "above" the other element or feature. Thus, the exemplary term "beneath" can include both an above and a below orientation. Additionally, the device may be otherwise positioned (e.g., rotated 90 degrees or at other orientations), and accordingly, the spatial relative descriptors used herein are to be interpreted accordingly.

[0061] The terms used herein are for the purpose of describing particular embodiments and are not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular forms "a," "an," and "the" are also intended to include the plural forms. In addition, when the terms "comprises," "comprising," and / or their variants are used in this specification, it is specified that there are the stated features, integers, steps, operations, elements, components, and / or groups thereof, but it does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should also be noted that, as used herein, the terms "substantially," "about," and other similar terms are used as approximate terms and not as terms of degree, so they are used to explain the inherent deviations of measured values, calculated values, and / or provided values that would be recognized by those of ordinary skill in the art.

[0062] 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 disclosure pertains. Terms (such as those defined in a general dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and should not be interpreted in an ideal or overly formal sense unless expressly so defined herein.

[0063] Figure 1 is a perspective view of a display device according to an exemplary embodiment.

[0064] Referring to Figure 1 , the display device 1 displays a moving image or a still image. Examples of the display device 1 may include a mobile phone, a smart phone, a tablet personal computer (PC), an electronic watch, a smart watch, a watch phone, a mobile communication terminal, an electronic notebook, an e-book, a portable multimedia player (PMP), a vehicle navigation device, a game console, a digital camera, a television, a laptop computer, a monitor, a billboard, and an Internet of Things device, etc., which provide a display screen.

[0065] The display device 1 includes an active area AAR and a non-active area NAR. The active area AAR is an area where the main functions of the display device 1 are implemented and may include a display area for displaying a screen. The active area AAR may also include a touch area for sensing a touch input. The display area may include a plurality of pixels, and the touch area may include a plurality of touch sensing units. The display area and the touch area may be stacked on top of each other in the thickness direction. The active area AAR may have a rectangular shape, a square shape, other polygonal shapes, a circular shape, an oval shape, etc., but the exemplary embodiments of the present disclosure are not limited thereto. The active area AAR may also include two or more planes. For example, the display device 1 may be bent, folded, or curled such that the active area AAR is disposed on multiple planes.

[0066] The non-active area NAR may be disposed around the active area AAR. The non-active area NAR may be a border area. The screen may not be displayed in the non-active area NAR. That is, the non-active area NAR may include the non-display area of the display device 1. The non-active area NAR may not include a touch area (i.e., be a non-touch area), but the exemplary embodiments of the present disclosure are not limited thereto. A touch unit or a pressure sensor may be disposed on at least a part of the non-active area NAR to detect an input signal according to a touch or a pressure. In the non-active area NAR, signal lines or driving circuits for applying signals to the active area AAR (display area or touch area) may be disposed.

[0067] The non-active area NAR may be disposed to surround the active area AAR. When the active area AAR has a rectangular shape, the non-active area NAR may have a rectangular frame shape surrounding the rectangle. When the active area AAR has a circular shape, the non-active area NAR may have an annular shape surrounding the circle. However, the exemplary embodiments of the present disclosure are not limited thereto. As in the borderless display device 1, the entire surface of the display device 1 may be formed only by the active area AAR in the thickness direction such that there is no non-active area NAR. Alternatively, the non-active area NAR may be disposed only on a part of the side surface of the active area AAR, and the active area AAR itself may form the edge of the display device 1 on the other parts of the side surface without the non-active area NAR.

[0068] Figure 2 is Figure 1 a cross-sectional view of the display device. Referring to Figure 2 , the display device 1 may include a display panel 10, a touch member 20 disposed on one surface (the upper side in the figure) of the display panel 10, and a vibration member (also referred to as a vibrator) VBR disposed on the other surface (the lower side in the figure) of the display panel 10.

[0069] The display panel 10 is used to provide a display screen. The display panel 10 includes a plurality of pixels that are basic units of the screen. Examples of the display panel 10 may include an organic light-emitting display panel, a micro LED display panel, a nano LED display panel, a quantum dot light-emitting display panel, a plasma display panel, a field emission display panel, an electro-wetting display panel, a liquid crystal display panel, and an electrophoretic display panel, etc.

[0070] When the display panel 10 is a light-emitting panel such as an organic light-emitting display panel, the display panel 10 may include a first electrode (e.g., an anode), a second electrode (e.g., a cathode), and a light-emitting layer interposed between the first electrode and the second electrode. When the light-emitting panel is an active type, the display panel 10 may include a driving circuit (such as a thin-film transistor, etc.) for driving each pixel. The first electrode may be a pixel electrode provided for each pixel, and the second electrode may be a common electrode provided over a plurality of pixels. The light-emitting layer may be an organic light-emitting layer, a micro LED (micro light-emitting diode), a nano LED (nano light-emitting diode), a quantum dot layer, or a fluorescent layer, etc.

[0071] When the display panel 10 is a light-receiving panel such as a liquid crystal display panel 10, the display device 1 further includes a light-providing member such as a backlight unit. The display panel 10 may include a first electrode and a second electrode for generating an electric field and a light transmittance control member. The behavior of the light transmittance control member can be controlled by the electric field generated by the first electrode and the second electrode. When the light-receiving panel is an active type, the display panel 10 may include a driving circuit (such as a thin-film transistor) for driving each pixel. The first electrode may be a pixel electrode provided for each pixel, and the second electrode may be a common electrode provided over a plurality of pixels. The light transmittance control member may be a liquid crystal layer or light-blocking electrophoretic particles, etc.

[0072] The display panel 10 can be rigid or flexible. The rigid display panel 10 can use a rigid substrate (such as a glass substrate) as the base substrate. The flexible display panel 10 can be bent, folded, or curled. In the case of the flexible display panel 10, a flexible plastic that can be bent (such as polyimide or ultra-thin glass) can be used as the material of the base substrate.

[0073] The touch member 20 may be disposed on one surface of the display panel 10. One surface of the display panel 10 may be a surface (or display surface) in the display direction. The touch member 20 includes a plurality of touch units. Each touch unit may be defined by one or more touch electrodes. The size of the touch unit of the touch member 20 may be larger than the size of a pixel. The touch unit may have, for example, a rhombus shape or a square shape with one side being about 4 mm, but the exemplary embodiments of the present disclosure are not limited thereto. The touch member 20 may identify whether a touch gesture occurs by a self-capacitance method or a mutual-capacitance method, but the exemplary embodiments of the present disclosure are not limited thereto.

[0074] The touch member 20 may be disposed in the form of a panel or a film. The touch member 20 may be attached to one surface of the display panel 10 through a first transparent bonding layer 61 (such as an optically clear adhesive (OCA) or an optically clear resin (OCR)). In another embodiment, the touch member 20 may be integrally disposed inside the display panel 10. For example, touch electrodes may be formed on the electrodes of the light-emitting elements constituting the display panel 10 to serve as the touch member 20. Optionally, at least one of the electrodes constituting the light-emitting element (for example, the second electrode serving as the cathode electrode of an organic light-emitting display panel) may be used together as a touch electrode to serve as the touch member 20.

[0075] A window member 30 may be further disposed on the touch member 20. The window member 30 may cover and protect the display panel 10. The window member 30 may be attached to one surface of the touch member 20 through a second transparent bonding layer 62 (such as an optically clear adhesive (OCA) or an optically clear resin (OCR)). The window member 30 may be larger than the display panel 10, and the edge of the window member 30 may protrude from the edge of the display panel 10.

[0076] The window member 30 may include a window substrate 31 and a printed layer 32.

[0077] The window substrate 31 may be made of a transparent material. The window substrate 31 may be formed to include, for example, glass or plastic. When the window substrate 31 includes plastic, the window substrate 31 may have a flexible property.

[0078] The printed layer 32 may be disposed on the window substrate 31. The printed layer 32 may be disposed on one surface and / or the other surface of the window substrate 31. The printed layer 32 may be disposed on the edge portion of the window substrate 31 and may be disposed on the non-effective area NAR. The printed layer 32 may be a decorative layer and / or an outermost black matrix layer that imparts aesthetic appeal.

[0079] The vibration member VBR may be disposed on the other surface of the display panel 10. The other surface of the display panel 10 may be the opposite surface of the surface of the display panel 10 that serves as the display surface. The vibration member VBR may be disposed in contact with the other surface (rear surface) of the display panel 10. Here, the fact that the vibration member VBR is disposed on the other surface of the display panel 10 includes not only the case where the vibration member VBR is directly disposed on the other surface of the display panel 10, but also the case where the vibration member VBR is disposed on the other surface of the display panel 10 and another layer or panel is interposed therebetween. In addition, the fact that the vibration member VBR is in contact with the other surface of the display panel 10 can be interpreted to include not only the case where the vibration member VBR is in direct contact with the other surface of the display panel 10, but also the case where the vibration member VBR is in contact with the other surface of the display panel 10 through other members (such as a bonding layer).

[0080] In one exemplary embodiment, the display device 1 may further include a cover panel 40 disposed on the other surface of the display panel 10. The cover panel 40 may be attached to the other surface of the display panel 10 through a bonding layer 63 (including an adhesive, etc.) between the panels. The bonding layer 63 may be disposed on one surface of the cover panel 40. When the display device 1 includes the cover panel 40, the vibration member VBR may be disposed on the other surface of the cover panel 40 facing away from the bonding layer 63 or attached to the other surface of the cover panel 40 facing away from the bonding layer 63. Hereinafter, as an example, the case where the vibration member VBR is attached to the cover panel 40 disposed to overlay the other surface of the display panel 10 will be described, but the exemplary embodiments of the present disclosure are not limited thereto. In the absence of the cover panel 40, the vibration member VBR is directly attached to the other surface of the display panel 10. Alternatively, the vibration member VBR may be disposed in the periphery of the cover panel 40 or in an area exposed by a hole and may be directly attached to the other surface of the display panel 10. In addition, the vibration member VBR may be disposed between the display panel 10 and the cover panel 40 or inside the cover panel 40.

[0081] The cover panel 40 may include at least one functional layer. The functional layer may be a layer that performs a heat dissipation function, an electromagnetic shielding function, a grounding function, a buffering function, a rigidity enhancing function, a support function, a bonding function, a pressure sensing function, and / or a digitizing function, etc. The functional layer may be a sheet layer, a film layer, a thin film layer, a coating, a panel, or a plate, etc. One functional layer may be composed of a single layer or a stack of multiple thin films or coatings. The functional layer may be, for example, a support substrate, a heat dissipation layer, an electromagnetic shielding layer, a shock absorption layer, a bonding layer, a pressure sensor, or a digitizer, etc.

[0082] The vibration member VBR may include a plurality of vibrators VBR that are separated from each other. Each vibrator VBR may be arranged to be individually attached to or in contact with the other surface of the display panel 10 or the cover panel 40, but the vibrator VBR may be arranged to be in contact with (or attached to) the other surface of the display panel 10 or the cover panel 40 in an array state on a member (such as a plate, film, or sheet) having a predetermined area.

[0083] The vibration member VBR may be operated by a driving signal. The vibration member VBR may generate vibration waves and provide the vibration waves to the display panel 10. The vibration waves may propagate through the display panel 10 in the thickness direction and / or the plane direction. The vibration waves generated by the vibration member VBR may provide a tactile sensation or sound to the display device 1.

[0084] Figure 3 is a layout diagram of a cover panel and a vibrator according to an exemplary embodiment.

[0085] As Figure 3 shown, a plurality of vibrators VBR may be arranged on the other surface of the cover panel 40. The vibrators VBR may be separated from each other. Each vibrator VBR may perform a vibration operation and generate vibration waves. The vibration waves generated by the vibrators VBR may be amplified or canceled while cooperating (overlapping) with each other. The interaction of the waves may be used to amplify or attenuate the vibration to perform precise tactile operations or generate sound.

[0086] The plurality of vibrators VBR may include piezoelectric elements or exciters. The exciter may include a voice coil. The exciter may be a linear resonant actuator (LRA) that generates a magnetic force by using the voice coil to vibrate the cover panel 40 and the display panel 10 in the vertical (perpendicular) direction, but the exemplary embodiments of the present disclosure are not limited thereto. Hereinafter, the piezoelectric elements and the exciters will be described in detail.

[0087] Figure 4 is a cross-sectional view of a piezoelectric element according to an exemplary embodiment. Figure 5 is a conceptual diagram for explaining the operating characteristics of the piezoelectric element.

[0088] Referring to Figure 4 and Figure 5 , the piezoelectric element 400 may include a first electrode 410, a second electrode 420 facing the first electrode 410, and a vibration material layer 430 interposed between the first electrode 410 and the second electrode 420. The piezoelectric element 400 may be attached to the cover panel 40 through an element bonding layer 65.

[0089] The first electrode 410 and the second electrode 420 may be made of a conductive material. For example, the first electrode 410 and the second electrode 420 may include a transparent conductor (such as indium tin oxide (ITO) or indium zinc oxide (IZO)), an opaque metal, a conductive polymer, or carbon nanotubes (CNTs), etc.

[0090] The vibration material layer 430 may include a piezoelectric material that vibrates in response to an electric field. For example, the vibration material layer 430 may include at least one of a piezoelectric body (such as lead zirconate titanate (PZT)), a piezoelectric film (such as a polyvinylidene fluoride (PVDF) film), and an electroactive polymer.

[0091] The vibration material layer 430 may be compressed or relaxed according to the polarity of the voltage. For example, as Figure 5 shown, when a positive voltage is applied to the first electrode 410 and a negative voltage is applied to the second electrode 420, a compressive force F1 may appear in the vibration material layer 430 and the vibration material layer 430 may be compressed in the thickness direction. On the other hand, when a negative voltage is applied to the first electrode 410 and a positive voltage is applied to the second electrode 420, a relaxation force F2 may appear in the vibration material layer 430 and the vibration material layer 430 may expand in the thickness direction. Therefore, when an alternating voltage having an alternating polarity is applied to the first electrode 410 and the second electrode 420, the vibration material layer 430 may repeatedly contract and expand. Due to this phenomenon, vibrations may occur in the cover panel 40 and the display panel 10 adjacent to each other. The vibrations generated by the piezoelectric element 400 may propagate along the display panel 10.

[0092] Figure 6 is an exploded perspective view of an actuator according to an exemplary embodiment.

[0093] Referring to Figure 6 , an actuator 500 according to an exemplary embodiment may include a lower chassis 521, a flexible circuit board 522, a voice coil 523, a magnet 524, a spring 525, and an upper chassis 526. The lower chassis 521 and the upper chassis 526 may be formed of a metallic material. The flexible circuit board 522 is disposed on one surface of the lower chassis 521 facing the upper chassis 526 and is connected to a first signal line WL1 and a second signal line WL2. The voice coil 523 may be connected to one surface of the flexible circuit board 522 facing the upper chassis 526. Accordingly, one end of the voice coil 523 may be electrically connected to the first signal line WL1 (or the first sound line), and the other end of the voice coil 523 may be electrically connected to the second signal line WL2 (or the second sound line). The magnet 524 is a permanent magnet, and a voice coil groove 524a in which the voice coil 523 is received may be formed on one surface of the magnet 524 facing the voice coil 523. The spring 525 is disposed between the magnet 524 and the upper chassis 526.

[0094] The direction of the current flowing through the voice coil 523 can be controlled based on the first driving voltage applied to the first signal line WL1 and the second driving voltage applied to the second signal line WL2. Based on the current flowing through the voice coil 523, a magnetic field can be generated around the voice coil 523. According to the AC driving of the first driving voltage and the second driving voltage, attractive and repulsive forces can act alternately between the magnet 524 and the voice coil 523. Therefore, the magnet 524 can reciprocate between the voice coil 523 and the upper chassis 526 through the spring 525, which can cause the vibrating surface provided on the upper chassis 526 to vibrate.

[0095] Figure 7 is a perspective view of an actuator according to another exemplary embodiment.

[0096] Referring to Figure 7 , the actuator 501 may include a magnet MG, a bobbin BB, a voice coil VC, and a damper DP.

[0097] The magnet MG is a permanent magnet, and a sintered magnet of barium ferrite may be used as the magnet MG. The magnet MG may be made of iron oxide (Fe 2 O 3 ), barium carbonate (BaCO 3 ), a neodymium magnet, a strontium ferrite with improved magnetic properties, an alloy cast magnet of cobalt (Co), nickel (Ni), or aluminum (Al), but the exemplary embodiments of the present disclosure are not limited thereto. For example, the neodymium magnet may be neodymium-iron-boron (Nd-Fe-B).

[0098] The magnet MG may be formed in a cylindrical shape. The magnet MG may include a central protrusion CPP protruding from the center of the plate and a side wall portion SW protruding from the edge of the plate. The central protrusion CPP and the side wall portion SW may be separated from each other at a predetermined interval, and thus, a predetermined space may be formed between the central protrusion CPP and the side wall portion SW. That is, a circular space may be provided on the bottom of the cylindrical magnet MG.

[0099] The central protrusion CPP of the magnet MG may have an N polarity, and the plate and the side wall portion SW of the magnet MG may have an S polarity. Therefore, an external magnetic field may be formed between the plate and the central protrusion CPP and between the central protrusion CPP and the side wall portion SW of the magnet MG.

[0100] The bobbin BB can be formed into a cylindrical shape. The central protrusion CPP of the magnet MG can be disposed in the bobbin BB. That is, the bobbin BB can be arranged to surround the central protrusion CPP of the magnet MG. In addition, the side wall portion SW of the magnet MG can also be disposed outside the bobbin BB. That is, the side wall portion SW of the magnet MG can also be arranged to surround the bobbin BB. A space can be formed between the bobbin BB and the central protrusion CPP of the magnet MG and between the bobbin BB and the side wall portion SW of the magnet MG.

[0101] The bobbin BB can be formed of a material processed from pulp or paper, aluminum or magnesium, or their alloys, synthetic resins (such as polypropylene), or polyamide fibers.

[0102] The voice coil VC is wound around the outer circumferential surface of the bobbin BB. One end of the voice coil VC adjacent to one end of the bobbin BB can be connected to the first signal line WL1 (or the first sound line), and the other end of the voice coil VC adjacent to the other end of the bobbin BB can be connected to the second signal line WL2 (or the second sound line). Thus, current can flow in the voice coil VC according to the first driving voltage applied to the first signal line WL1 and the second driving voltage applied to the second signal line WL2. According to the current flowing through the voice coil VC, a magnetic field can be formed around the voice coil VC. According to the AC driving of the first driving voltage and the second driving voltage, the N polarity and S polarity of the applied magnetic field formed around the voice coil VC change. Therefore, the attractive force and the repulsive force can alternately act between the magnet MG and the voice coil VC. Accordingly, the bobbin BB around which the voice coil VC is wound can reciprocate in the thickness direction (or the vertical direction), thereby vibrating the cover panel 40 and the display panel 10.

[0103] The damper DP can be disposed between a part of the upper side of the bobbin BB and the side wall portion SW of the magnet MG. The damper DP adjusts the vertical vibration of the bobbin BB while contracting and relaxing according to the vertical movement of the bobbin BB. Since the damper DP is connected to the bobbin BB and the side wall portion SW of the magnet MG, the vertical movement of the bobbin BB can be restricted by the restoring force of the damper DP. For example, when the bobbin BB vibrates at a predetermined height or greater or at a predetermined height or less, the bobbin BB can return to its initial position by the restoring force of the damper DP.

[0104] Referring again to Figure 3 , the plurality of vibrators VBR can include a main vibrator VBR_M and a sub-vibrator VBR_S. In one exemplary embodiment, both the main vibrator VBR_M and the sub-vibrator VBR_S can include a piezoelectric element ( Figure 4 400 in Figure 6 ), or can include an actuator ( Figure 7in <501>. As another example, the main vibrator VBR_M may include the piezoelectric element 400 and any one of the exciters <500> and <501>, and the sub-vibrator VBR_S may include the other one. When the main vibrator VBR_M or the sub-vibrator VBR_S is provided in plurality, the vibrators VBR constituting the plurality of main vibrators VBR_M or the plurality of sub-vibrators VBR_S may have the same type, but may also have different types. For example, some sub-vibrators VBR_S may include the piezoelectric element 400, and some sub-vibrators VBR_S may include the exciter <500>.

[0105] The main vibrator VBR_M may provide a main vibration wave to the display panel <10>. The sub-vibrator VBR_S generates a sub-vibration wave. The sub-vibration wave may be an interference vibration wave that meets (or overlaps) with the main vibration wave and undergoes constructive or destructive interference with the main vibration wave to control the waveform, amplitude, etc. of the vibration wave transmitted to the display panel <10>.

[0106] In one exemplary embodiment, the main vibrator VBR_M and the sub-vibrator VBR_S may be distinguished by the maximum amplitude of the vibration wave. For example, the main vibration wave generated by the main vibrator VBR_M may have a first maximum amplitude in the region where the main vibrator VBR_M is located, and the sub-vibration wave generated by the sub-vibrator VBR_S may have a second maximum amplitude in the region where the sub-vibrator VBR_S is located. In this case, the first maximum amplitude may be larger than the second maximum amplitude. However, the exemplary embodiments of the present disclosure are not limited thereto. The main vibration wave and the sub-vibration wave may have the same maximum amplitude. Optionally, the vibrator VBR that forms a vibration wave having a maximum amplitude larger than that of the main vibration wave may be used as the sub-vibrator VBR_S.

[0107] In an exemplary embodiment, each of the main vibrator VBR_M and the sub-vibrator VBR_S may have a shape extending in one direction. The sub-vibrator VBR_S may be arranged such that its extending direction is parallel to the adjacent edge. The length of the main vibrator VBR_M may be larger than the length of the sub-vibrator VBR_S; however, the exemplary embodiments of the present disclosure are not limited thereto.

[0108] The sub-vibrator VBR_S can be disposed around the main vibrator VBR_M. A plurality of sub-vibrators VBR_S can be provided. In one exemplary embodiment, the plurality of sub-vibrators VBR_S can at least partially surround one main vibrator VBR_M. The main vibrator VBR_M can be located in the central region of the display device 1 or the display panel 10, and the plurality of sub-vibrators VBR_S can be disposed along the edge of the display device 1 or the display panel 10. The main vibrator VBR_M and the sub-vibrators VBR_S can be separated from each other in the horizontal direction, and the sub-vibrators VBR_S can be separated from each other. The spacing distance between the main vibrator VBR_M and the sub-vibrators VBR_S disposed around the main vibrator VBR_M can be uniform, but can be different as shown in the figure. The spacing distance between the sub-vibrators VBR_S can be uniform, but the exemplary embodiments of the present disclosure are not limited thereto.

[0109] The relative positions of the sub-vibrator VBR_S and the main vibrator VBR_M are not limited by Figure 3 the examples shown therein. For example, in another embodiment, the sub-vibrator VBR_S can be disposed in the central region, and the main vibrator VBR_M can be disposed around the sub-vibrator VBR_S. In some cases, a vibrator VBR can be used as the main vibrator or the sub-vibrator according to the mode. For example, in the first mode (e.g., the sound mode), the vibrator VBR located in the central region can be used as the main vibrator, and the vibrators VBR located around it can be used as sub-vibrators to amplify or cancel the main vibration wave of the main vibrator. In the second mode (e.g., the haptic mode), the vibrator VBR located in the central region can be used as the sub-vibrator to amplify or cancel the main vibration wave of the main vibrator, and the vibrators VBR located around it can be used as the main vibrator. Hereinafter, the case where the sub-vibrator VBR_S is disposed around the main vibrator VBR_M will be mainly described as an example. However, unless described based on a specific position, the same description applies to the embodiments with opposite positions.

[0110] The phase of the main vibration wave generated by the main vibrator VBR_M and the phase of the sub-vibration wave generated by the sub-vibrator VBR_S can be different. In addition, the phases of the sub-vibration waves generated by the sub-vibrators VBR_S can be different from each other. Each sub-vibrator VBR_S can generate sub-vibration waves with different phases according to the spacing distance from the main vibrator VBR_M. A detailed description thereof will be given later.

[0111] Figure 8 is a graph showing the relationship between the amplitude of the vibration wave of a vibrator and the distance. Figure 9 is a diagram showing the vibration waveform in a medium at a certain distance over time when the vibrator operates.

[0112] As shown Figure 8 in, vibration waves are generated in the region where the vibrator VBR is located, and the vibration waves propagate to the surroundings. The amplitude (or displacement) of the vibration waves depends on the distance from the region where the vibrator VBR is located. Generally, the amplitude of the vibration waves can decrease as the vibration waves move away from the position of the vibrator VBR. When a vibrator VBR vibrates uniformly, as shown Figure 9 in, the amplitude of the vibration waves at a specific position can be uniformly maintained. As described above, when driving the vibrator VBR, the vibrator VBR repeats contraction and expansion, and the vibration period T of the vibration waves can be defined by the period of the contraction / expansion of the vibrator VBR. The vibration period T of the vibration waves can be the same regardless of the position, but the exemplary embodiments of the present disclosure are not limited thereto.

[0113] Vibration waves are a type of wave, and when multiple waves are mixed, constructive interference or destructive interference can occur. Here, constructive interference refers to the situation where the vibration waves are superimposed and the amplitude at a specific position becomes larger, and destructive interference refers to the situation where the vibration waves are superimposed and the amplitude at a specific position becomes smaller. Constructive interference has the maximum amplitude increase effect when the superimposed vibration waves have the same phase, and destructive interference has the maximum amplitude decrease effect when the phases of the superimposed vibration waves are opposite (i.e., differ by 180°). However, the constructive interference and destructive interference of the exemplary embodiments of the present disclosure are not limited to the above phase relationships. Even if there is a slight difference from the phase relationship, when the amplitude becomes larger than the amplitude of a single vibration wave, it is also called constructive interference, and when the amplitude becomes smaller than the amplitude of a single vibration wave, it is also called destructive interference.

[0114] Figure 10 and Figure 11 are graphs showing the superimposed waveform of the vibration waves of two vibrators according to the phase difference.

[0115] Figure 10 is a graph when the first vibration wave WV1 generated by the first vibrator VBR1 and the second vibration wave WV2 generated by the second vibrator VBR2 have the same phase at the same time at a specific position. As shown Figure 10 in, when the first vibration wave WV1 and the second vibration wave WV2 have the same phase at a specific position, constructive interference occurs while their waveforms overlap with each other. That is, the first vibration wave WV1 and the second vibration wave WV2 are added together, and their amplitude becomes larger. The amplitude of the vibration wave WV_OV superimposed at a specific position can be the sum of the amplitude of the first vibration wave WV1 and the amplitude of the second vibration wave WV2.

[0116] Figure 11It is a graph when the first vibration wave WV1 generated by the first vibrator VBR1 and the second vibration wave WV2 generated by the second vibrator VBR2 have opposite phases at a specific position at the same time. As Figure 11 shown, when the first vibration wave WV1 and the second vibration wave WV2 have opposite phases (i.e., a phase difference of 180°), destructive interference occurs, causing their waveforms to cancel each other out. In other words, in this case, the superimposed vibration wave WV_OV at the specific position is the difference between the absolute value of the first vibration wave WV1 and the absolute value of the second vibration wave WV2, and its amplitude becomes smaller than the amplitude when only a single vibration wave exists. If the first vibration wave WV1 and the second vibration wave WV2 have the same amplitude and opposite phases at a specific position, then no vibration may occur at the corresponding position.

[0117] By utilizing this phenomenon, it is possible to amplify or reduce the amplitude of the vibration wave transmitted through the medium. For example, in order to achieve precise tactile operations, it is preferable to maintain or increase the amplitude of the vibration at the position where touch input is performed and reduce the vibration in other areas. In the area around the touch area, the amplitude can be increased by constructive interference of the waveforms in the same way as Figure 10 . In the area far from the touch area, the amplitude can be reduced by causing destructive interference of the waveforms in the same way as Figure 11 . If only one of constructive interference and destructive interference needs to be driven, then selecting and driving destructive interference can more effectively intensify the vibration only at specific positions.

[0118] In Figure 10 and Figure 11 , the phases of the first vibration wave WV1 and the second vibration wave WV2 can be adjusted by adjusting the phases of the AC voltages applied to the first electrode and the second electrode of each vibrator VBR. For example, assuming that the two vibrators VBR use the piezoelectric element 400 shown in Figure 4 , then at the moment when the positive maximum voltage of the AC voltage is applied to the first electrode of the first vibrator VBR1, a vibration wave with the same phase can be generated when the positive maximum voltage of the AC voltage is applied to the first electrode of the second vibrator VBR2, and a vibration wave with the opposite phase can be generated when the positive maximum voltage of the AC voltage is applied to the second electrode of the second vibrator VBR2.

[0119] Meanwhile, Figure 10 and Figure 11This shows a case where the spacing distance between the first vibrator VBR1 and the second vibrator VBR2 is an integer multiple of 1 / 2 of the wavelengths of the first vibration wave WV1 and the second vibration wave WV2. This is a method of making the phase of the second vibration wave WV2 have the same phase or a 180° phase difference relative to the phase of the first vibration wave WV1. In this method, when using a vibrator VBR with a predetermined wavelength, if the position of one vibrator VBR is determined, then the candidate positions of the other vibrator VBR can also be specified. For example, when the position of the main vibrator VBR_M is determined, a plurality of sub-vibrators VBR_S around the main vibrator VBR_M need to be arranged at the same spacing distance from the main vibrator VBR_M. Due to the touch input position or other reasons, this may be an obstacle to differently modifying the arrangement of the vibrators VBR on the display panel 10. In addition, when the wavelength of the vibrator VBR is larger than the size of the display panel 10 and the vibrators VBR cannot be separated by an integer multiple of 1 / 2 of the wavelength, it is difficult to achieve constructive interference and destructive interference through the above same-phase (0° phase difference) and opposite-phase (180° phase difference) methods. This results in restricting the vibrators VBR used for constructive interference and destructive interference in the display device 1 to vibrators VBR that generate short-wavelength vibration waves.

[0120] In order to be able to achieve constructive interference and destructive interference even when long-wave vibrators VBR are arranged at various spacing distances, the phase of the vibrator VBR according to the embodiment can be adjusted according to the distance (spacing distance) from the surrounding vibrators VBR. The phase difference of the vibration wave of one vibrator VBR relative to the vibration wave of another vibrator VBR can have various other values as well as the above 0° and 180°. In an exemplary embodiment, the phase difference of the vibration wave of the one vibrator VBR relative to the vibration wave of the another vibrator VBR can be greater than 0° and less than 180°.

[0121] Figure 12 is a schematic diagram showing the arrangement of the main vibrator and the sub-vibrators and their vibration waves according to an exemplary embodiment.

[0122] Referring to Figure 12 , each of the main vibrator VBR_M and the sub-vibrators VBR_S has a wavelength of λ, and the distance between the main vibrator VBR_M and the sub-vibrators VBR_S is d. Here, d can be smaller than 1 / 2 of λ.

[0123] As described above, in order to cancel the main vibration wave WV_M of the main vibrator VBR_M, the sub-vibration wave WV_S of the sub-vibrator VBR_S preferably has an opposite phase. That is, preferably, when the main vibration wave WV_M has a peak (the highest part of the wave) at the position of the sub-vibrator VBR_S, the sub-vibration wave WV_S of the sub-vibrator VBR_S has a trough (the lowest part of the wave). The trough and the peak have a phase difference of 180°. However, since it takes time for the main vibration wave WV_M to travel to the position of the sub-vibrator VBR_S, when the actual main vibration wave WV_M has a peak at the position of the sub-vibrator VBR_S, the main vibration wave WV_M at the position of the main vibrator VBR_M may have a phase other than the peak. Therefore, considering the driving of the vibrator VBR, it is necessary to reflect such a phase difference so that maximum destructive interference can be achieved at the actually overlapping part.

[0124] When the phase of the main vibration wave WV_M in the region where the main vibrator VBR_M is located is θ1 and the phase at a position separated from the main vibrator VBR_M by d is θ2, the difference θ1 - θ2 between the phases can satisfy the following Equation 1:

[0125] θ1 - θ2 = (360° × d) / λ Equation 1

[0126] Therefore, in order to amplify or cancel the main vibration wave WV_M, the phase difference between the sub-vibrator VBR_S at a position separated from the main vibrator VBR_M by d and the main vibrator VBR_M can satisfy the following Equation 2:

[0127] Δθ = 180° × n - (360° × d) / λ Equation 2

[0128] In Equation 2, n is an integer, and Δθ represents the difference (i.e., the phase delay value) between the phase of the sub-vibration wave WV_S of the sub-vibrator VBR_S and the phase of the main vibration wave WV_M. Here, if the phase difference or the phase delay value is positive, it can represent that the phase of the sub-vibration wave WV_S is delayed by the corresponding value compared with the main vibration wave WV_M, and if the phase difference or the phase delay value is negative, it can represent that the phase of the sub-vibration wave WV_S is earlier than the corresponding value compared with the main vibration wave WV_M. In addition, the phase difference can represent the difference in phase at the same moment.

[0129] When n in Equation 2 is an even number, the phase delay value is basically equal to -(360° × d) / λ. In this case, when the sub-vibration wave WV_S of the sub-vibrator VBR_S has a phase difference of -(360° × d) / λ with respect to the main vibration wave WV_M of the main vibrator VBR_M, since both the main vibration wave WV_M and the sub-vibration wave WV_S have peaks at the position of the sub-vibrator VBR_S, effective constructive interference can be achieved.

[0130] When n in Equation 2 is an odd number, the phase delay value is substantially equal to 180° - (360°×d) / λ. In this case, when the main vibration wave WV_M has a peak at the position of the sub-vibrator VBR_S, since the sub-vibration wave WV_S has a valley, effective destructive interference can be achieved. When the wavelength of the main vibration wave WV_M is the same as the wavelength of the sub-vibration wave WV_S, the superimposed main vibration wave WV_M and sub-vibration wave WV_S can have destructive interference in the same manner regardless of the position along the traveling direction of the superimposed waves.

[0131] Figure 13 is a graph showing the vibration intensity (or displacement) of the vibration wave according to the distance. Figure 13 shows that in Figure 12 the phase of the sub-vibration wave WV_S of the sub-vibrator VBR_S has a phase difference of 180° - (360°×d) / λ with respect to the phase of the main vibration wave WV_M of the main vibrator VBR_M, resulting in the vibration intensity when maximum destructive interference occurs.

[0132] Referring to Figure 13 , as described above, the farther the vibration wave is from the vibrator VBR, the smaller the vibration intensity becomes. The main vibration wave WV_M generated by the main vibrator VBR_M can be maximally canceled when it reaches the position where the maximum sub-vibration wave VW_S of the sub-vibrator VBR_S is generated. Even before and after the sub-vibrator VBR_S, the main vibration wave WV_M can be canceled to reduce the vibration intensity. In addition, in the portion where the main vibrator VBR_M is located, the vibration intensity of the main vibration wave WV_M may be reduced due to the influence of the sub-vibration wave WV_S. However, also in the case of the sub-vibration wave WV_S, the vibration intensity decreases as it moves away from the sub-vibrator VBR_S. Therefore, at the actual position of the main vibrator VBR_M, the degree of cancellation of the vibration intensity of the main vibration wave WV_M is relatively small. Therefore, the superimposed vibration wave WV_OV maintains a strong vibration intensity near the region where the main vibrator VBR_M is located, but the vibration intensity may rapidly decrease as the superimposed vibration wave WV_OV moves away from the main vibrator VBR_M. In this way, when performing a haptic operation, vibration can be selectively generated only at the position where the actual touch input is made, thereby achieving precise haptic operation. In the same way, since precise vibration control is possible, precise sound control can be performed when the vibration member VBR is used as a sound generating element or the like.

[0133] To confirm the superposition result of the above-mentioned multiple vibration waves, two vibrators VBR are attached to a panel (covering panel 40 or display panel 10), and the gravitational force equivalent (G) value according to the phase is measured. The vibrators VBR are attached to one side of the panel, and the G sensor is placed on the other surface of the panel. One vibrator VBR is attached at a distance of 3 cm to the left from the center of the panel, and the other vibrator VBR is attached at a distance of 3 cm to the right from the center of the panel. The spacing distance between the vibrators VBR is 6 cm. The wavelength of each vibrator VBR is 1.93 m. The G sensor is placed at the center of the panel.

[0134] First, the same voltage of 250 Hz and 5 Vpp is applied to each vibrator VBR using a function generator. After checking the speed of the vibration wave transmitted through the panel, the phase difference is applied. The G value is measured while changing the phase. In addition, the level of decibels (dB) is measured at a distance of 30 cm.

[0135] At Figure 14 、 Figure 15 and Figure 16 show the results of the above experiment. Figure 14 is a graph showing the relationship between the G value and the phase difference. Figure 15 is a graph showing the relationship between the log(G) value and the phase difference. Figure 16 is a graph showing the relationship between the decibel level and the phase difference.

[0136] Referring to Figure 14 、 Figure 15 and Figure 16 , in the above experimental example, when the phase difference is 168.8° (= 180° - 11.2°), the G value is 0. In the corresponding stage, the decibel level is below 30 dB, indicating a level that can be controlled to be substantially noise. It is confirmed that the log(G) graph is roughly consistent with the decibel level graph.

[0137] Referring again to Figure 3, the main vibrator VBR_M may be disposed in a central region of the cover panel 40 (or the display panel 10 stacked with the cover panel 40 in the thickness direction), and a plurality of sub-vibrators VBR_S may be disposed along the edge of the cover panel 40 (or the display panel 10 stacked with the cover panel 40 in the thickness direction). In one exemplary embodiment, one main vibrator VBR_M may be located in the center of the cover panel 40. The sub-vibrators VBR_S may be arranged in a row. The array of sub-vibrators VBR_S may have a rectangular shape similar to that of the cover panel 40. Each sub-vibrator VBR_S may be disposed at a substantially same distance from the edge of the cover panel 40. The spacing between adjacent sub-vibrators VBR_S disposed at each edge of the cover panel 40 may be uniform, but the exemplary embodiments of the present disclosure are not limited thereto.

[0138] When the cover panel 40 has a rectangular shape in a plan view, even if the main vibrator VBR_M is located in the central region of the cover panel 40, the spacing distances between the main vibrator VBR_M in the central region and the sub-vibrators VBR_S in the edge portion may be different. For example, one sub-vibrator VBR_S may be separated from the main vibrator VBR_M by a first distance d1, and another sub-vibrator VBR_S may be separated from the main vibrator VBR_M by a second distance d2.

[0139] Here, the spacing distances d1, d2 may refer to the distances by which the main vibrator VBR_M and the sub-vibrators VBR_S are separated from each other based on the positions where the vibration waves of the vibrator VBR are generated. When the entire region where the vibrator VBR is provided provides uniform vibration, the vibration waves may propagate from the edge of the vibrator VBR. In this case, the spacing distances d1, d2 between the vibrators VBR may be measured as the shortest distances between the edges of adjacent vibrators VBR as shown in Figure 3 If the vibration waves generated by the vibrator VBR have a maximum value at a specific position inside the vibrator VBR or along a specific line and propagate therefrom, the shortest distances between the specific positions or the specific lines of the respective vibrators VBR may be measured as the spacing distances d1, d2.

[0140] For constructive interference driving that applies overall vibration to the display panel 10, when the wavelength of the vibration wave of each vibrator VBR is λ, the constructive interference driving can be driven by Equation 2 above, such that the vibration wave of the sub-vibrator VBR_S at the first distance d1 has a phase delay value of {180°×2m(360°×d1) / λ} relative to the vibration wave of the main vibrator VBR_M, and the vibration wave of the sub-vibrator VBR_S at the second distance d2 has a phase delay value of {180°×2m-(360°×d2) / λ} relative to the vibration wave of the main vibrator VBR_M. If the first distance d1 and the second distance d2 are different from each other, then the phase of the vibration wave of the sub-vibrator VBR_S at the first distance d1 and the phase of the vibration wave of the sub-vibrator VBR_S at the second distance d2 can also be different from each other.

[0141] In addition, for destructive interference driving that achieves precise haptic operation around the main vibrator VBR_M, the destructive interference driving can be driven such that the vibration wave of the sub-vibrator VBR_S at the first distance d1 has a phase delay value of {180°×(2m + 1)-(360°×d1) / λ} relative to the vibration wave of the main vibrator VBR_M, and the vibration wave of the sub-vibrator VBR_S at the second distance d2 has a phase delay value of {180°×(2m + 1)-(360°×d2) / λ} relative to the vibration wave of the main vibrator VBR_M. If the first distance d1 and the second distance d2 are different from each other, then the phase of the vibration wave of the sub-vibrator VBR_S at the first distance d1 and the phase of the vibration wave of the sub-vibrator VBR_S at the second distance d2 can also be different from each other.

[0142] As described above, when the phase of the vibration wave of each vibrator VBR is adjusted differently according to the interval distance, even if the vibrators VBR are arranged at various intervals, constructive / destructive interference driving can be effectively performed. For the phase control of each vibrator VBR, the display device 1 may further include a phase controller (not shown) capable of driving each vibrator VBR with various phases. The phase controller can control the phase of each vibration wave by adjusting the phase of the AC voltage supplied to each vibrator VBR.

[0143] Hereinafter, other embodiments will be described.

[0144] Figure 17 is a layout diagram of a cover panel and vibrators according to another exemplary embodiment. Figure 18 is a layout diagram of a cover panel and vibrators according to still another exemplary embodiment.

[0145] In Figure 17 and Figure 18 In the embodiments of, the display device 1 may include a plurality of main vibrators VBR_M. AsFigure 17 As shown, multiple main vibrators VBR_M can be arranged in a row at a predetermined interval in the central region of the cover panel 40. As Figure 18 shown, multiple main vibrators VBR_M can be arranged in multiple rows (two rows in the figure) at a predetermined interval in the central region of the cover panel 40. The sub-vibrators VBR_S can be arranged around the outside of the array of the multiple main vibrators VBR_M. The sub-vibrators VBR_S can be not arranged between the main vibrators VBR_M.

[0146] In some embodiments, the main vibrators VBR_M can generate main vibration waves or sub-vibration waves. In one driving mode, each of the multiple main vibrators VBR_M can generate a main vibration wave. The phases of the main vibration waves of the respective main vibrators VBR_M can be adjusted so that constructive interference occurs between them. The sub-vibrators VBR_S outside the array of the main vibrators VBR_M can be driven to have a phase difference so that destructive interference occurs between the superimposed main vibration waves of the main vibrators VBR_M.

[0147] In another driving mode, some of the multiple main vibrators VBR_M can generate main vibration waves, and the other main vibrators VBR_M can generate vibration waves that cancel the main vibration waves. In an exemplary embodiment, among the multiple main vibrators VBR_M, the main vibrators VBR_M that generate main vibration waves are the main vibrators VBR_M close to the position where touch input is performed, and the remaining main vibrators VBR_M can generate sub-vibration waves (or destructive interference vibration waves). The sub-vibrators VBR_S outside the array of the main vibrators VBR_M can be driven to have a phase difference so that more destructive interference occurs between the superimposed vibration waves of the main vibrators VBR_M.

[0148] Figure 19 is a layout diagram of a cover panel and vibrators according to yet another exemplary embodiment. Referring to Figure 19 this embodiment, the same as the embodiment of Figure 17 is that multiple main vibrators VBR_M are arranged in a row, but different from the embodiment of Figure 17 is that multiple sub-vibrators VBR_S are arranged between the main vibrators VBR_M.

[0149] Specifically, the sub-vibrator VBR_S is provided not only at the edge of the cover panel 40 but also in the central region between the main vibrators VBR_M. Each main vibrator VBR_M can be surrounded by the sub-vibrator VBR_S. Each main vibrator VBR_M can generate a main vibration wave, and the sub-vibrator VBR_S can generate a sub-vibration wave that undergoes constructive or destructive interference with the main vibration wave. The main vibration wave generated by the main vibrator VBR_M can interfere with the sub-vibration wave generated by the sub-vibrator VBR_S surrounding the main vibrator VBR_M. The sub-vibrators VBR_S between the main vibrators VBR_M can be arranged in a row and can generate sub-vibration waves for all adjacent main vibrators VBR_M. That is, the sub-vibrators VBR_S between the main vibrators VBR_M can be shared to interfere with the main vibration waves on both sides.

[0150] Figure 20 is a layout diagram of a cover panel and vibrators according to another exemplary embodiment. Referring to Figure 20 , this embodiment is the same as that of Figure 19 in that multiple sub-vibrators VBR_S are provided between the main vibrators VBR_M, but is different from the embodiment of Figure 19 in that the multiple sub-vibrators VBR_S between the main vibrators VBR_M are arranged in two rows. The first row of sub-vibrators VBR_S between the main vibrators VBR_M can generate sub-vibration waves that interfere with the main vibration waves of the main vibrators VBR_M on one side, and the second row of sub-vibrators VBR_S between the main vibrators VBR_M can generate sub-vibration waves that interfere with the main vibration waves of the main vibrators VBR_M on the other side.

[0151] Figure 21 is a layout diagram of a cover panel and vibrators according to another exemplary embodiment. In the embodiment of Figure 21 , one main vibrator VBR_M can be surrounded by multiple rows of sub-vibrators VBR_S. Specifically, this embodiment is different from the embodiment of Figure 19 in that the sub-vibrators VBR_S surrounding each main vibrator VBR_M are arranged in two rows. The sub-vibrators VBR_S in the first row and the sub-vibrators VBR_S in the second row can be arranged alternately, but the exemplary embodiments of the present disclosure are not limited thereto. Three rows of sub-vibrators VBR_S can be provided between the main vibrators VBR_M, and the sub-vibrators VBR_S in the middle row can be shared to interfere with the main vibration waves on both sides.

[0152] Figure 22 is a layout diagram of a cover panel and vibrators according to another exemplary embodiment. This embodiment is the same as that of Figure 20 in that multiple sub-vibrators VBR_S surround each main vibrator VBR_M, but is different fromFigure 20 The embodiment is different in that: the sub-vibrator VBR_S is placed at substantially the same interval distance from the main vibrator VBR_M. In this embodiment, when a main vibrator VBR_M generates a main vibration wave, the surrounding sub-vibrators VBR_S are driven to have an optimal phase difference according to the interval distance, but the sub-vibrators VBR_S around one main vibrator VBR_M can have the same phase. However, the exemplary embodiments of the present disclosure are not limited thereto. For the purpose of controlling the direction in which the main vibration wave propagates, the sub-vibrators VBR_S at the same distance can have different phases.

[0153] As described above, when the phases of the vibration waves of each vibrator VBR are adjusted differently according to the interval distance to cause constructive / destructive interference, the haptic operation can be precisely performed. The display device can increase the user's immersion in the application by providing different haptic interfaces according to the progress state of the application and the user's touch input in the application. Hereinafter, exemplary haptic interfaces using the above-described vibrator VBR will be described.

[0154] Figure 23 is a table showing a method for providing a haptic interface of a display device according to an exemplary embodiment. Figure 23 shows a method for providing a haptic interface according to the game situation and the user's touch input when the display device is executing an application for a car racing game. Figure 24 is shown as provided with Figure 23 the application execution screen of a display device with a haptic interface.

[0155] The display device includes a main vibrator and sub-vibrators. One main vibrator can be provided, but multiple main vibrators can also be provided. In one exemplary embodiment, the main vibrator can include a first main vibrator stacked below the first acceleration icon AI1 or disposed around the first acceleration icon AI1, and a second main vibrator stacked below the second acceleration icon AI2 or disposed around the second acceleration icon AI2. Hereinafter, the case where the first main vibrator and the second main vibrator simultaneously generate main vibration waves having the same amplitude and frequency will be described. However, the first main vibrator and the second main vibrator can generate main vibration waves having different amplitudes or frequencies, or can generate vibration waves at different times.

[0156] Multiple sub-vibrators can be provided around the first main vibrator and the second main vibrator. The first main vibrator, the second main vibrator, and the sub-vibrators can have as Figure 17 , Figure 18 , Figure 19 , Figure 20 , Figure 21 and Figure 22The various relative arrangements shown. In some embodiments, a main vibrator may be provided, in which case it may have Figure 3 the arrangement shown in

[0157] Referring to Figure 23 , when counting down the start of a race in a racing game application, the display device may cause the main vibrator to vibrate at a maximum amplitude of 52 and a frequency of 46 Hz for 298 ms. Here, the maximum amplitude of 52 is a relative value of the amplitude of the vibration waveform of the main vibrator or the sub-vibrator. In this case, the main vibrator may vibrate during a period of 298 ms while the amplitude increases four times and decreases four times. The main vibrator may rise four times with the same amplitude at the same intervals, and fall four times with the same amplitude at the same intervals. In the above steps, while the main vibrator is vibrating, the sub-vibrator may vibrate at the same frequency and with different phases according to the interval positions to achieve destructive interference.

[0158] In a racing game application, when the car starts, the display device may cause the main vibrator to vibrate at a maximum amplitude of 66 and a frequency of 62 Hz for 736 ms. In the above steps, while the main vibrator is vibrating, the sub-vibrator may vibrate at the same frequency and with different phases according to the interval positions to achieve destructive interference.

[0159] In a racing game application, when the user touches the first acceleration icon AI1, the display device may cause the main vibrator to vibrate at a maximum amplitude of 60 and a frequency of 203 Hz for 98 ms. In this case, the main vibrator may vibrate within 98 ms while increasing the amplitude three times. In this case, the main vibrator may rise three times with the same amplitude at the same intervals. In Figure 23 , the number of times the amplitude increases is shown as three, but the exemplary embodiments of the present disclosure are not limited thereto. The number of times the amplitude increases may be N times. In the above steps, while the main vibrator is vibrating, the sub-vibrator may vibrate at the same frequency and with different phases according to the interval positions to achieve destructive interference.

[0160] In a racing game application, when the user touches the second acceleration icon AI2, the display device may cause the main vibrator to vibrate at a maximum amplitude of 60 and a frequency of 203 Hz for 201 ms. When the user touches the second acceleration icon AI2, the vibration period of the main vibrator may be longer than the vibration period when touching the first acceleration icon AI1. In Figure 23In [the situation], it is shown that when the user touches the first acceleration icon AI1, the frequency and maximum amplitude of the main vibrator are the same as those when the user touches the second acceleration icon AI2. However, the exemplary embodiments of the present disclosure are not limited thereto. When the user touches the first acceleration icon AI1, the frequency and maximum amplitude of the main vibrator may be different from those when the user touches the second acceleration icon AI2. In addition, in this case, the main vibrator may vibrate five times while increasing the amplitude within 201 ms. In this case, the main vibrator may rise five times with the same amplitude at the same interval. In the above steps, while the main vibrator is vibrating, the sub-vibrator may vibrate at the same frequency and with different phases according to the interval position to achieve destructive interference.

[0161] In a racing game application, when a car collides with another car or an object, the display device may cause the main vibrator to vibrate at a maximum amplitude of 50 and a frequency of 148 Hz for 47 ms. In this case, the main vibrator may vibrate during the 47-ms period while increasing the amplitude once and decreasing the amplitude once. The main vibrator may rise once with the same amplitude at the same interval and fall once with the same amplitude at the same interval. In Figure 23 [the situation], it is shown that the number of times of increasing / decreasing the amplitude is one. However, the exemplary embodiments of the present disclosure are not limited thereto. The number of times of increasing the amplitude may be N times, and the number of times of decreasing the amplitude may be M times. In the above steps, while the main vibrator is vibrating, the sub-vibrator may vibrate at the same frequency and with different phases according to the interval position to achieve destructive interference.

[0162] In a racing game application, when a car drifts, the display device may cause the main vibrator to vibrate at a maximum amplitude of 52 and a frequency of 46 Hz for 725 ms. In this case, the main vibrator may vibrate during the 725-ms period while increasing the amplitude once and decreasing the amplitude once. The main vibrator may rise once with the same amplitude at the same interval and fall once with the same amplitude at the same interval. In Figure 23 [the situation], it is shown that the number of times of increasing / decreasing the amplitude is one. However, the exemplary embodiments of the present disclosure are not limited thereto. The number of times of increasing the amplitude may be N times, and the number of times of decreasing the amplitude may be M times.

[0163] In a racing game application, when a car stops, the display device may cause the main vibrator to vibrate at a maximum amplitude of 59 and a frequency of 15 Hz for 2500 ms. In the above steps, while the main vibrator is vibrating, the sub-vibrator may vibrate at the same frequency and with different phases according to the interval position to achieve destructive interference.

[0164] As described above, while the main vibrator vibrates, the sub-vibrator can vibrate at the same frequency and with different phases according to the interval positions to achieve destructive interference, thereby improving the tactile sensitivity at the touch position.

[0165] In addition, according to Figure 23 and Figure 24 In the embodiment shown in, when the user performs a first touch input for touching the first acceleration icon AI1, the display device can generate a first vibration by using the main vibrator and / or the sub-vibrator to provide a first tactile interface. In addition, when the user performs a second touch input for touching the second acceleration icon AI2, the display device can generate a second vibration different from the first vibration by using the main vibrator and / or the sub-vibrator to provide a second tactile interface different from the first tactile interface. For example, as Figure 23 shown in, the period of the second vibration can be longer than the period of the first vibration. In this case, when the user performs a second touch input for touching the second acceleration icon AI2, the vibration can be perceived for a longer time compared to when performing a first touch input for touching the first acceleration icon AI1. In addition, the user can feel that the effect of car acceleration performed by touching the second acceleration icon AI2 in a racing game application is higher than the effect of car acceleration performed by touching the first acceleration icon AI1.

[0166] Meanwhile, in Figure 23 it is shown that only the periods of the first vibration and the second vibration are different, and the frequency and amplitude of the first vibration are the same as those of the second vibration, but the exemplary embodiments of the present disclosure are not limited thereto. For example, the frequency, amplitude, and period of the first vibration can be different from those of the second vibration respectively. Alternatively, the frequency and amplitude of the first vibration can be different from those of the second vibration respectively. Alternatively, the frequency and period of the first vibration can be different from those of the second vibration respectively. Alternatively, the amplitude and period of the first vibration can be different from those of the second vibration respectively. Alternatively, the frequency of the first vibration can be different from the frequency of the second vibration. Alternatively, the amplitude of the first vibration can be different from the amplitude of the second vibration.

[0167] As described above, due to the change in at least one of the frequency, amplitude, and period of the vibration, the user can feel that the first vibration and the second vibration are different. In addition, it can be perceived that precise tactile operation is achieved through the destructive interference of the sub-vibrator.

[0168] Although certain exemplary embodiments and implementations have been described herein, other embodiments and modifications will be apparent from this description. Therefore, the inventive concept is not limited to such embodiments, but to the appended claims and the broader scope of various obvious modifications and equivalent arrangements that will be apparent to those of ordinary skill in the art.

Claims

1. A display device, the display device comprising: a display panel; a main vibrator, disposed on the display panel and configured to generate a main vibration wave; and a plurality of sub-vibrators, disposed on the display panel and separated from the main vibrator, the plurality of sub-vibrators being configured to generate sub-vibration waves respectively, wherein the plurality of sub-vibrators includes: a first sub-vibrator, disposed at a first distance from the main vibrator in a plan view, the first sub-vibrator being configured to generate a first sub-vibration wave; and a second sub-vibrator, disposed at a second distance from the main vibrator in the plan view, the second sub-vibrator being configured to generate a second sub-vibration wave having a phase different from that of the first sub-vibration wave, and wherein the second distance is different from the first distance, wherein the main vibration wave and the first sub-vibration wave have the same wavelength, wherein, the difference Δθ between the phase of the first sub-vibration wave and the phase of the main vibration wave 1 satisfies the following Equation 1: Δθ 1 = 180°×n - (360°×d1) / λ Equation 1 where n is an integer, d1 is the first distance between the main vibrator and the first sub-vibrator, and λ is the wavelength of the main vibration wave and the first sub-vibration wave.

2. The display device according to claim 1, wherein, the phase of the main vibration wave is different from the phase of the first sub-vibration wave and the phase of the second sub-vibration wave.

3. The display device according to claim 2, wherein, the main vibration wave, the first sub-vibration wave and the second sub-vibration wave have the same wavelength.

4. The display device according to claim 3, wherein, The difference Δθ between the phase of the second sub-vibration wave and the phase of the main vibration wave 2 satisfies the following Equation 2: Δθ 2 = 180° × n - (360° × d2) / λ Equation 2, where d2 is the second distance between the main vibrator and the second sub-vibrator, and λ is the wavelength of the main vibration wave, the first sub-vibration wave and the second sub-vibration wave.

5. The display device according to claim 4, wherein, each of the first distance and the second distance is smaller than half of the wavelength.

6. The display device according to claim 5, wherein, the difference between the phase of the first sub-vibration wave and the phase of the main vibration wave is greater than 0° and less than 180°, and where the difference between the phase of the second sub-vibration wave and the phase of the main vibration wave is greater than 0° and less than 180°.

7. The display device according to claim 2, wherein, the first sub-vibration wave and the second sub-vibration wave are configured to destructively interfere with the main vibration wave.

8. The display device according to claim 2, the display device further comprising: a phase controller, configured to control the phases of the AC voltages supplied to each of the first sub-vibrator and the second sub-vibrator and the main vibrator.

9. The display device according to claim 1, wherein, the maximum amplitude of the main vibrator is greater than the maximum amplitude of the first sub-vibrator or the maximum amplitude of the second sub-vibrator.

10. The display device according to claim 1, wherein, the plurality of sub-vibrators at least partially surround the main vibrator.

11. The display device according to claim 10, wherein, the main vibrator is disposed in a central region of the display panel in the plan view, and The multiple sub-vibrators are disposed along an edge of the display panel in the plan view.

12. The display device according to claim 1, the display device further comprises: a cover panel, stacked with the display panel, wherein the display panel includes a display surface and an opposite surface opposite to the display surface, wherein the cover panel is disposed on the opposite surface of the display panel, and the main vibrator and the multiple sub-vibrators are attached to the cover panel.

13. The display device according to claim 12, the display device further comprises: a touch member, disposed on the display surface of the display panel.

14. The display device according to claim 1, wherein, each of the main vibrator and the multiple sub-vibrators includes at least one of a piezoelectric element and an actuator.

15. The display device according to claim 1, wherein, the main vibrator includes a first main vibrator and a second main vibrator separated from each other in the plan view.

16. The display device according to claim 15, wherein, the multiple sub-vibrators surround the first main vibrator and the second main vibrator in the plan view.

17. The display device according to claim 16, wherein, in the plan view, the multiple sub-vibrators are not disposed between the first main vibrator and the second main vibrator.

18. The display device according to claim 15, wherein, the first main vibrator is configured to generate a first main vibration wave during a first driving mode, and wherein the second main vibrator is configured to generate a vibration wave to cancel the first main vibration wave during the first driving mode.

19. The display device according to claim 18, wherein, the first main vibrator is configured to generate the first main vibration wave during a second driving mode, and the second main vibrator is configured to generate a second main vibration wave that undergoes constructive interference with the first main vibration wave during the second driving mode.

20. A display device, the display device comprises: a display panel; a first vibrator, disposed on the display panel; and a second vibrator, disposed on the display panel and separated from the first vibrator, wherein a difference Δθ between phases of vibration waves of the second vibrator and vibration waves of the first vibrator satisfies the following equation: Δθ = 180°×n - (360°×d) / λ, wherein n is an integer, d is a distance between the first vibrator and the second vibrator, and λ is a wavelength of the vibration waves of the first vibrator and the vibration waves of the second vibrator.

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