Flexible vibration module and display device including the same

Abstract

A flexible vibration module and a display device including the flexible vibration module. A flexible vibration module is disclosed. The flexible vibration module includes a piezoelectric composite layer, the piezoelectric composite layer includes a plurality of piezoelectric parts each having a piezoelectric property and a flexible part between the plurality of piezoelectric parts, wherein at least two of the plurality of piezoelectric parts have different sizes.

Description

Technical Field

[0001] The present disclosure relates to a display device, and more particularly, to a flexible vibration module and a display device including the same. Background Art

[0002] In a display device, a display panel displays an image, and a separate speaker for providing sound should be installed. In some prior art embodiments, a speaker is provided in the display device, and the speaker occupies space. As a result, the design and spatial arrangement of the display device are limited.

[0003] A speaker applied to a display device may be, for example, an actuator including a magnet and a coil. However, the thickness of the actuator is high. Therefore, it may be desirable to use a piezoelectric element with a lower thickness.

[0004] Since the piezoelectric element may be brittle, the piezoelectric element may be easily damaged by external impact. Therefore, the reliability of sound reproduction may be low. Summary of the invention

[0005] Accordingly, the present disclosure is directed to a flexible vibration module and a display device including the same that substantially obviate one or more of the above-mentioned problems due to limitations and disadvantages of the related art.

[0006] The speaker applied to the display device may be a membrane type vibration module. The membrane type vibration module may be manufactured to have a large area and thus may be applied to a large area display device, but it may be difficult to apply the membrane type vibration module to a large area display device due to low vibration caused by low piezoelectric characteristics. Ceramics may be applied to enhance piezoelectric characteristics. As a result, durability may be weak and the size of the ceramic may be limited.

[0007] In a vibration module including a piezoelectric composite layer, ceramics may be applied to a display device. As a result, the piezoelectric composite layer may mainly vibrate in the horizontal direction of the display device. This may make it difficult for the display device to fully vibrate in the vertical direction. As a result, the display device may not be able to output a desired sound to a front area in front of the display device.

[0008] Alternatively, a film-type piezoelectric material may be applied to a display device, resulting in a lower sound pressure characteristic of the display device than that of a general speaker (e.g., an exciter). In some embodiments, a film-type piezoelectric configured with a plurality of layers to increase sound pressure may be applied to a display device. As a result, power consumption increases.

[0009] A vibration module can enhance piezoelectric properties, stiffness, and flexibility. The vibration module may be formed of a composite layer including a filler having a high dielectric constant and low piezoelectric properties. As a result, the vibration module may not achieve the desired sound. In some example embodiments of the present disclosure, the vibration module may be formed of a piezoelectric ceramic having piezoelectric properties, and may be formed of an organic material in order to enhance stiffness and flexibility.

[0010] In other example embodiments, the vibration module may be formed of a piezoelectric ceramic having piezoelectric properties, and may be formed of a material such as a polymer to reduce the brittleness of the piezoelectric ceramic. In these example embodiments, the vibration module may be configured so that a material such as a polymer is in a piezoelectric ceramic composite, and the vibration module has flexibility. In these example embodiments, the vibration module may have various vibration frequencies, the sound pressure characteristics may be enhanced, and the sound reproduction band may be extended. In these example embodiments, the display device includes a vibration module of a new structure for enhancing piezoelectric properties, stiffness, and flexibility.

[0011] An aspect of the present disclosure is to provide a flexible vibration module having enhanced piezoelectric characteristics, rigidity, and flexibility, and a display device including the same.

[0012] Another aspect of the present disclosure is to provide a flexible vibration module that enhances sound pressure characteristics and expands a sound reproduction band based on various vibration frequencies, and a display device including the same.

[0013] Another aspect of the present disclosure is to provide a display device that outputs sound generated based on vibration of a display panel to a front area in front of the display panel.

[0014] To achieve these and other aspects of the inventive concept and in accordance with the purposes of the present disclosure, as implemented and broadly described, a flexible vibration module includes: a piezoelectric composite layer, the piezoelectric composite layer including a plurality of piezoelectric parts each having a piezoelectric property, wherein at least two of the plurality of piezoelectric parts have different sizes; and a flexible part between the plurality of piezoelectric parts.

[0015] In another aspect of the present disclosure, a flexible vibration module includes: a piezoelectric composite layer, wherein the piezoelectric composite layer includes: a plurality of piezoelectric portions each having a piezoelectric characteristic; and a flexible portion between the plurality of piezoelectric portions. The piezoelectric composite layer has a plurality of vibration frequencies.

[0016] In another aspect of the present disclosure, a display device includes: a flexible vibration module, the flexible vibration module including: a piezoelectric composite layer, the piezoelectric composite layer including a plurality of piezoelectric parts each having a piezoelectric property, wherein at least two of the plurality of piezoelectric parts have different sizes; and a flexible part between the plurality of piezoelectric parts; and a display panel, wherein the display panel includes a display area, the display area is configured to display an image and vibrate according to the vibration of the flexible vibration module.

[0017] According to the present disclosure, most of the area in the display panel will vibrate through the film-type large-area flexible vibration module. Therefore, the localization of the sound based on the vibration of the display panel can be further enhanced, thereby achieving a stereo effect.

[0018] In addition, according to the present disclosure, the display panel can vibrate according to various vibration frequencies to output sound. Therefore, the sound pressure characteristics of the sound can be increased and the sound reproduction band can be expanded.

[0019] It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the inventive concepts as claimed.

[0020] Note 1. A flexible vibration module, the flexible vibration module comprising:

[0021] A piezoelectric composite layer, comprising:

[0022] a plurality of piezoelectric portions each having a piezoelectric property, wherein at least two of the plurality of piezoelectric portions have different sizes; and

[0023] A flexible portion is provided between the plurality of piezoelectric portions.

[0024] Supplementary Note 2. The flexible vibration module according to claim 1, wherein each of the plurality of piezoelectric portions has a different size and a different vibration frequency.

[0025] Note 3. The flexible vibration module according to Note 1, wherein:

[0026] At least two of the plurality of piezoelectric portions have different lengths, different widths, and different thicknesses.

[0027] Note 4. The flexible vibration module according to Note 1, wherein one of the length, width and thickness of each of the plurality of piezoelectric parts gradually increases or decreases in a direction from at least one end of the piezoelectric composite layer to a central portion of the piezoelectric composite layer.

[0028] Supplementary note 5. The flexible vibration module according to Supplementary note 1, wherein one of the length, width and thickness of each of the plurality of piezoelectric portions is randomly changed between one end and the other end of the piezoelectric composite layer.

[0029] Note 6. The flexible vibration module according to Note 1, wherein one of the length, width and thickness of each of the plurality of piezoelectric parts gradually increases or decreases in a direction from one end of the piezoelectric composite layer to another end opposite to the one end.

[0030] Supplement 7. The flexible vibration module according to Supplement 1, wherein each of the plurality of piezoelectric parts comprises:

[0031] a lower piezoelectric portion; and

[0032] An upper piezoelectric portion is disposed on the lower piezoelectric portion.

[0033] Supplementary note 8. The flexible vibration module according to Supplementary note 7, wherein all of the plurality of piezoelectric portions have the same thickness.

[0034] Supplementary note 9. The flexible vibration module according to Supplementary note 7, wherein at least two of the lower piezoelectric portions have different thicknesses.

[0035] Note 10. The flexible vibration module according to Note 7, wherein:

[0036] The plurality of piezoelectric portions have the same thickness, and

[0037] A thickness of each of the lower piezoelectric portions changes stepwise or randomly in a direction from one end portion of the piezoelectric composite layer to another end portion opposite to the one end portion.

[0038] Note 11. The flexible vibration module according to Note 7 further comprises an electrode between the lower piezoelectric part and the upper piezoelectric part.

[0039] Note 12. The flexible vibration module according to Note 7, further comprising:

[0040] a first electrode between the lower piezoelectric portion and the upper piezoelectric portion;

[0041] a second electrode between the lower piezoelectric portion and the upper piezoelectric portion; and

[0042] An insulating layer is provided between the first electrode and the second electrode.

[0043] Note 13. A flexible vibration module, comprising:

[0044] A piezoelectric composite layer, comprising:

[0045] a plurality of piezoelectric portions each having a piezoelectric characteristic; and

[0046] a flexible portion between the plurality of piezoelectric portions,

[0047] Wherein, the piezoelectric composite layer has multiple vibration frequencies.

[0048] Supplementary note 14. The flexible vibration module according to Supplementary note 13, wherein at least two of the plurality of piezoelectric parts have different vibration frequencies.

[0049] Supplementary note 15. The flexible vibration module according to Supplementary note 13, wherein the vibration frequency of each of the plurality of piezoelectric portions changes stepwise or randomly in a direction from one end of the piezoelectric composite layer to another end opposite to the one end.

[0050] Supplement 16. The flexible vibration module according to Supplement 13, wherein each of the plurality of piezoelectric parts comprises:

[0051] a lower piezoelectric portion; and

[0052] An upper piezoelectric portion is disposed on the lower piezoelectric portion.

[0053] Note 17. The flexible vibration module according to Note 16, wherein:

[0054] The plurality of piezoelectric portions have the same thickness, and

[0055] The thickness of each of the lower piezoelectric portions gradually becomes thicker or thinner in a direction from at least one end portion of the piezoelectric composite layer to a central portion of the piezoelectric composite layer.

[0056] Note 18. The flexible vibration module according to Note 13, wherein:

[0057] Each of the plurality of piezoelectric portions comprises an inorganic material, and

[0058] The flexible portion includes at least one of an organic piezoelectric material and an organic non-piezoelectric material.

[0059] Note 19. A display device, comprising:

[0060] A flexible vibration module, the flexible vibration module comprising:

[0061] A piezoelectric composite layer, comprising:

[0062] a plurality of piezoelectric portions each having a piezoelectric property, wherein at least two of the plurality of piezoelectric portions have different sizes; and

[0063] a flexible portion between the plurality of piezoelectric portions; and

[0064] A display panel, wherein the display panel includes a display area configured to display an image and vibrate according to the vibration of the flexible vibration module.

[0065] Supplement 20. The display device according to Supplement 19, further comprising a touch electrode configured to sense a touch, wherein the flexible vibration module is configured to vibrate according to the touch.

[0066] Note 21. The display device according to Note 19, wherein:

[0067] Each of the plurality of piezoelectric portions comprises an inorganic material; and

[0068] The flexible portion includes at least one of an organic piezoelectric material and an organic non-piezoelectric material.

[0069] Supplement 22. The display device according to Supplement 19, wherein:

[0070] The display panel includes a first area and a second area;

[0071] The flexible vibration module is a first flexible vibration module in the first area of ​​the display panel; and

[0072] A second flexible vibration module is in the second area of ​​the display panel.

[0073] Note 23. The display device according to Note 22, further comprising:

[0074] a rear structure on a rear surface of the display panel; and

[0075] At least one partition member is between the display panel and the rear structure and between the first flexible vibration module and the second flexible vibration module.

[0076] Note 24. The display device according to Note 22, further comprising:

[0077] a rear structure on a rear surface of the display panel; and

[0078] a spacer between the display panel and the rear structure,

[0079] The partition surrounds at least one of the first flexible vibration module and the second flexible vibration module.

[0080] Note 25. The display device according to Note 24, further comprising another partition between the display panel and the rear structure, the other partition surrounding both the first flexible vibration module and the second flexible vibration module and the partition. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] The accompanying drawings, which are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this application, illustrate example embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. In the drawings:

[0082] Figure 1 is a perspective view of a display device according to an embodiment of the present disclosure;

[0083] Figure 2 It is along Figure 1 A cross-sectional view taken along line II' illustrated in FIG.

[0084] Figure 3 A flexible vibration module according to a first embodiment of the present disclosure is illustrated;

[0085] Figure 4 It is along Figure 3 A cross-sectional view taken along line II-II' illustrated in FIG.

[0086] Figure 5 A flexible vibration module according to a second embodiment of the present disclosure is illustrated;

[0087] Figure 6 A flexible vibration module according to a third embodiment of the present disclosure is illustrated;

[0088] Figure 7 A flexible vibration module according to a fourth embodiment of the present disclosure is illustrated;

[0089] Figure 8 It is along Figure 7 A cross-sectional view taken along line III-III' illustrated in FIG.

[0090] Fig. 9 A flexible vibration module according to a fifth embodiment of the present disclosure is illustrated;

[0091] Fig.10 It is along Fig. 9 A cross-sectional view taken along line IV-IV' illustrated in FIG.

[0092] Fig.11 Illustrated Fig. 9A modified example embodiment of the flexible vibration module illustrated in;

[0093] Fig.12 It is along Figure 1 Another cross-sectional view taken along line II' illustrated in FIG.

[0094] Fig.13 Illustrated Fig.12 The flexible vibration module and the separator illustrated in the example;

[0095] Fig.14 Illustrated Fig.12 The flexible vibration module and the separator illustrated in the example;

[0096] Fig.15A , Fig. 15B and Fig. 15C Illustrated Fig.14 A modified example embodiment of the first flexible vibration module and the second flexible vibration module illustrated in;

[0097] Fig.16A , Fig. 16B and Fig. 16C Various display devices to which the flexible vibration module according to the embodiments of the present disclosure can be applied are illustrated;

[0098] Fig.17 is a graph showing sound pressure characteristics of a display panel according to an embodiment of the present disclosure and sound pressure characteristics of a display panel according to a comparative example. DETAILED DESCRIPTION

[0099] Now, reference will be made in detail to example embodiments of the present disclosure, examples of which may be illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the accompanying drawings to represent the same or similar components. The advantages and features of the present disclosure and methods for implementing the same will be illustrated by the following example embodiments described with reference to the accompanying drawings. However, the present disclosure may be implemented in different ways and should not be construed as being limited to the example embodiments set forth herein. On the contrary, these example embodiments are provided so that the present disclosure will be thorough and complete, and the scope of the present disclosure will be fully conveyed to those skilled in the art.

[0100] The shapes, sizes, ratios, angles, and quantities disclosed in the accompanying drawings for describing example embodiments of the present disclosure are merely examples, and therefore, the present disclosure is not limited to the illustrated details. Like reference numerals refer to like elements throughout. In the following description, when a detailed description of the related known technology unnecessarily obscures the main points of the present disclosure, the detailed description may be omitted.

[0101] Although the terms "first", "second", etc. may be used in the present disclosure to describe various elements, these elements should not be limited by these terms. These terms can be used to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the present disclosure.

[0102] The term "at least one" may include any and all combinations of one or more of the associated listed items. The features of the various example embodiments of the present disclosure may be coupled or combined with each other in part or in whole, and may interact with each other in various ways. The example embodiments of the present disclosure may be performed independently of each other, or may be performed together in a mutually dependent relationship.

[0103] Although the same elements may be illustrated in multiple drawings, similar reference numerals may refer to similar elements. In addition, for ease of description, each ratio of the elements illustrated in the drawings may be different from the actual ratio, and therefore, is not limited to the ratio illustrated in the drawings.

[0104] Figure 1 is a perspective view of a display device according to an embodiment of the present disclosure, and Figure 2 It is along Figure 1 A cross-sectional view taken along line II' illustrated in FIG.

[0105] like Figure 1 to Figure 2 As illustrated, the display device according to an embodiment of the present disclosure may include a display panel 100 and a flexible vibration module 300 disposed on a rear surface of the display panel 100 .

[0106] The display panel 100 according to the present disclosure may be a curved display panel or one of all types of display panels such as a liquid crystal display panel, an organic light emitting display panel, a quantum dot light emitting display panel, a micro light emitting diode display panel, and an electrophoretic display panel. For example, if the display panel 100 according to the present disclosure vibrates under the action of the flexible vibration module 300 to generate sound waves (or sounds) or generates tactile feedback in response to a touch, the display panel 100 is not limited to a specific display panel.

[0107] In some embodiments, the display panel 100 may include: a thin film transistor (TFT) array substrate including a plurality of pixels defined by a plurality of gate lines and a plurality of data lines and a TFT in each of the plurality of pixels for driving each of the plurality of pixels; a light emitting device layer on the TFT array substrate; and an encapsulation substrate covering the light emitting device layer. For example, the encapsulation substrate can protect the TFT and the organic light emitting device layer from external impact and can prevent water from penetrating into the organic light emitting device layer. The display panel 100 may include a display area that displays an image according to the driving of the plurality of pixels and a non-display area surrounding the display area.

[0108] The display panel 100 may include a curved portion that is curved or bent to have a curved shape or a specific radius of curvature. The curved portion of the display panel 100 may be in at least one of an edge (or periphery) and another edge (or periphery) of the display panel 100 that are parallel to each other. These edges may include only a non-display area, or may include edges or peripheries of a display area and a non-display area. In some embodiments, the display panel 100 may include a curved portion provided by bending a non-display area and may have a single-sided frame bending structure or a double-sided frame bending structure. In other example embodiments, the display panel 100 may include a curved portion provided by bending a non-display area and have a single-sided active bending structure or a double-sided active bending structure.

[0109] The display device according to an embodiment of the present disclosure may further include a functional film 130 disposed on the display panel 100. The functional film 130 may be disposed on the front surface of the display panel 100. In some embodiments, the functional film 130 may be attached to the front surface of the display panel 100 by a film bonding member. In some example embodiments, the film bonding member may include a pressure sensitive adhesive (PSA), an optically clear adhesive (OCA), or an optically clear resin (OCR). The functional film 130 may include at least one of an anti-reflection layer (or anti-reflection film) for preventing external light reflection, a barrier layer (or barrier film) for mainly preventing water or oxygen penetration, and an optical path control layer (or optical path control film) for controlling an optical path (or viewing angle).

[0110] The display device according to an embodiment of the present disclosure may further include a touch panel (or a touch electrode layer) for sensing a user touch applied to the display panel 100. For example, the touch panel may be disposed to overlap with the display area, and may function as a touch sensor for sensing a user touch applied to the display panel 100. For example, the touch panel may be disposed between the light emitting device layer and the encapsulation substrate, or may be disposed between the display panel 100 and the functional film 130. The touch panel may include a plurality of touch electrodes for sensing a change in capacitance caused by a user touch based on a mutual capacitance type or a self-capacitance type.

[0111] The flexible vibration module 300 may be disposed on the rear surface (or back side) of the display panel 100 and may vibrate the display panel 100. The flexible vibration module 300 may be a thin film type having various vibration frequencies (or natural vibration frequencies, or natural frequencies) based on piezoelectric characteristics and may have relatively high flexibility. For example, the flexible vibration module 300 may have a thickness thinner than that of the display panel 100. The flexible vibration module 300 may be referred to as a sound generating module, a sound generating device, a membrane actuator, a membrane-type piezoelectric composite actuator, a membrane speaker, a membrane-type piezoelectric speaker, or a membrane-type piezoelectric composite speaker. The flexible vibration module 300 may use the display panel 100 as a vibration plate.

[0112] The flexible vibration module 300 may be formed of a piezoelectric ceramic having piezoelectric properties. In order to improve the impact resistance of the piezoelectric ceramic and achieve flexibility, the flexible vibration module 300 may be formed of a material such as a polymer in the piezoelectric ceramic. In some example embodiments, the flexible vibration module 300 may include a piezoelectric ceramic having a perovskite crystal structure and may vibrate (or exhibit mechanical displacement) in response to an electrical signal applied from the outside.

[0113] The flexible vibration module 300 may vibrate at various vibration frequencies according to an electrical signal to vibrate the display panel 100. For example, the flexible vibration module 300 may vibrate according to a voice signal synchronized with an image displayed by the display panel 100 to vibrate the display panel 100. The sound generated based on the vibration of the display panel 100 may have a sound pressure characteristic that increases based on the vibration with various vibration frequencies. The vibration of the flexible vibration module 300 may extend the sound reproduction band. In another example embodiment, the flexible vibration module 300 may be disposed on the display panel 100 and may vibrate according to a tactile feedback signal (or tactile feedback signal) synchronized with a user touch applied to a touch panel (or touch sensor layer) built into the display panel 100 to vibrate the display panel 100. Therefore, the display panel 100 may vibrate based on the vibration of the flexible vibration module 300 to provide at least one of sound and tactile feedback to the user (or audience).

[0114] In addition, the flexible vibration module 300 according to the embodiment may have a size corresponding to the display area of ​​the display panel 100. The size of the flexible vibration module 300 may be 0.9 to 1.1 times the size of the display area, but is not limited thereto. For example, the size of the flexible vibration module 300 may be the same or substantially equal to the size of the display area of ​​the display panel 100, and therefore, the flexible vibration module 300 can cover most of the display panel 100. The vibration generated by the flexible vibration module 300 can vibrate the entire portion of the display panel 100, and therefore, the localization of the sound can be high and the user's satisfaction can be improved. The contact area (or panel coverage) between the display panel 100 and the flexible vibration module 300 can be increased, and therefore, the vibration area of ​​the display panel 100 can be increased. This improves the sound of the mid-to-low-pitched vocal band generated based on the vibration of the display panel 100. In a large-size display device, the entire portion of the display panel 100 having a large size (or a large area) may vibrate, and therefore, the sound localization based on the vibration of the display panel 100 can be enhanced, thereby achieving a stereo effect.

[0115] In some example embodiments, the flexible vibration module 300 may be attached to the rear surface of the display panel 100 by means of an adhesive member 200 (or a module adhesive member). The adhesive member 200 may be disposed between the rear surface of the display panel 100 and the flexible vibration module 300. For example, the adhesive member 200 may attach the flexible vibration module 300 to the rear surface of the display panel 100, and may be a double-sided tape or adhesive including an adhesive layer having a high adhesive force or attachment force. For example, the adhesive layer of the adhesive member 200 may include epoxy, acrylic, silicon, or polyurethane, but is not limited thereto. The adhesive layer of the adhesive member 200 may further include additives such as a tackifier or an adhesive enhancer, a wax component, or an antioxidant. The additive can prevent or reduce the detachment (or peeling) of the adhesive member 200 from the display panel 100 due to the vibration of the flexible vibration module 300. For example, the tackifier may be a rosin derivative, etc., the wax component may be a paraffin, etc., and the antioxidant may be a phenolic antioxidant such as a thioester. However, the present embodiment is not limited thereto.

[0116] According to another embodiment, the adhesive member 200 may further include a hollow portion between the display panel 100 and the flexible vibration module 300. The hollow portion of the adhesive member 200 may provide an air gap between the display panel 100 and the flexible vibration module 300. Due to the air gap, the sound wave (or sound pressure) based on the vibration of the flexible vibration module 300 is not dispersed by the adhesive member 200 and may be concentrated on the display panel 100. Therefore, the loss of vibration caused by the adhesive member 200 may be minimized or reduced, thereby increasing the sound pressure characteristics of the sound generated based on the vibration of the display panel 100.

[0117] The display device according to an embodiment of the present disclosure may further include a rear structure 500 supporting the display panel 100. The rear structure 500 may be referred to as a rear cover, a cover bottom, a board bottom, a back cover, a bottom frame, a metal frame, a metal chassis, a chassis base, or an m-chassis. The rear structure 500 may be a support member supporting the display panel 100, and may be any type of frame or board structure each disposed on the rear surface of the display device.

[0118] The rear structure 500 according to the embodiment may include a first rear cover 510 and a second rear cover 550. The first rear cover 510 may be a plate member covering the entire rear surface of the display panel 100. The first rear cover 510 may be spaced apart from the rearmost surface of the display panel 100 so as to have a gap space GS therebetween. For example, the gap space GS may be referred to as an air gap, a vibration space, or a sound box, but the term is not limited thereto. The second rear cover 550 may be a plate member disposed on the rear surface of the first rear cover 510 to cover the entire rear surface of the first rear cover 510.

[0119] The first back cover 510 and the second back cover 550 according to the embodiment may be coupled or connected to each other by a cover connection member 530. For example, the cover connection member 530 may be an adhesive resin, a double-sided adhesive tape, or a double-sided adhesive foam pad, and may have elasticity for absorbing impact. For example, the cover connection member 530 may be disposed in the entire area between the first back cover 510 and the second back cover 550. In another example embodiment, the cover connection member 530 may have a mesh structure including an air gap between the first back cover 510 and the second back cover 550.

[0120] The display device according to an embodiment of the present disclosure may further include an intermediate frame 600. The intermediate frame 600 may be disposed between a rear edge or a rear periphery of the display panel 100 and a front edge or a front periphery of the rear structure 500. The intermediate frame 600 may support an edge or a periphery of each of the display panel 100 and the rear structure 500, and may surround a side surface of each of the display panel 100 and the rear structure 500. The intermediate frame 600 may provide a gap space GS between the display panel 100 and the rear structure 500. The intermediate frame 600 may include an intermediate cabinet, an intermediate cover, or an intermediate chassis, but the term is not limited thereto.

[0121] The middle frame 600 according to the embodiment may include a support portion 610 and a side wall portion 630. The support portion 610 may be disposed between the rear edge or rear periphery of the display panel 100 and the front edge or front periphery of the rear structure 500, and thus, a gap space GS may be provided between the display panel 100 and the rear structure 500. The front surface of the support portion 610 may be coupled or connected to the rear edge or rear periphery of the display panel 100 by the first adhesive member 601, and the rear surface of the support portion 610 may be coupled or connected to the front edge or front periphery of the rear structure 500 by the second adhesive member 603. For example, the support portion 610 may have a quadrilateral single frame structure, or may have a plurality of split strip shapes, but is not limited thereto.

[0122] The side wall portion 630 may be vertically coupled or connected to the outer surface of the support portion 610 in parallel with the thickness direction Z of the display device. The side wall portion 630 may surround the entirety of the outer surface of the display panel 100 and the outer surface of the rear structure 500, and may protect the outer surface of each of the display panel 100 and the rear structure 500. The support portion 610 and the side wall portion 630 according to the embodiment may be coupled or connected to each other to constitute a single body, and thus may have a frame structure having a “┣”-shaped single-sided structure or a vertical single-sided structure.

[0123] The display device according to an embodiment of the present disclosure may include a panel connection member instead of the middle frame 600. The panel connection member may be disposed between the rear edge or rear periphery of the display panel 100 and the front edge or front periphery of the rear structure 500, and may provide a gap space GS between the display panel 100 and the rear structure 500. The panel connection member may be disposed between the rear edge or rear periphery of the display panel 100 and the edge or periphery of the rear structure 500, and may attach the display panel 100 to the rear structure 500. For example, the panel connection member may be a double-sided tape, a single-sided tape, or a double-sided adhesive foam pad, but is not limited thereto.

[0124] In some example embodiments, the display device may include a panel connection member instead of the middle frame 600. The rear structure 500 may include a side wall cover portion that is bent from the end of the second rear cover 550 and surrounds the entirety of the outer surface (or outer side wall) of each of the first rear cover 510, the panel connection member, and the display panel 100. The side wall cover portion according to the embodiment may have a single side wall structure or a curling structure. The curling structure may be a structure in which the ends of any member are bent into a curved shape to overlap each other or spaced apart in parallel with each other.

[0125] The display device according to an embodiment of the present disclosure can output a sound generated based on the vibration of the display panel 100 caused by the vibration of the flexible vibration module 300 provided on the rear surface of the display panel 100. The sound can be output to the front area FD in front of the display panel 100, thereby enhancing the immersion of the audience watching the image displayed by the display panel 100. Most areas of the display panel 100 can be vibrated by the flexible vibration module 300 having a film type and a large area. Therefore, the sound localization based on the vibration of the display panel 100 can be further enhanced, thereby achieving a stereo effect.

[0126] In some example embodiments, the display panel 100 may vibrate according to the driving of the flexible vibration module 300 having various vibration frequencies to output sound. Therefore, the sound pressure characteristics of the sound may be increased and the sound reproduction band may be expanded. In some example embodiments, even if a separate haptic driving device is not configured, the display panel 100 may vibrate based on the vibration of the flexible vibration module 300 disposed on the rear surface of the display panel 100 to provide the user with tactile feedback in response to the user's touch applied to the display panel 100.

[0127] Figure 3 The flexible vibration module 300 according to the first embodiment of the present disclosure is illustrated, and Figure 4 It is along Figure 3 A cross-sectional view taken along line II-II' illustrated in FIG. Figure 3 and Figure 4 Illustrated Figure 2 The flexible vibration module illustrated in FIG.

[0128] like Figure 3 and Figure 4 As illustrated, the flexible vibration module 300 according to the first embodiment of the present disclosure may include a piezoelectric composite layer 310, a first electrode layer 320, and a second electrode layer 330. The piezoelectric composite layer 310 may be a thin film type having various vibration frequencies (or natural frequencies or natural vibration frequencies) or multiple vibration frequencies based on piezoelectric characteristics and may have relatively high flexibility. The piezoelectric composite layer 310 according to the embodiment may include a plurality of piezoelectric portions 311 and a flexible portion 313 between the plurality of piezoelectric portions 311. The plurality of piezoelectric portions 311 and the flexible portion 313 may be arranged on the same plane (or the same layer). For example, the piezoelectric composite layer 310 may ensure piezoelectric characteristics and flexibility.

[0129] The piezoelectric composite layer 310 may have various shapes based on the arrangement structure of the plurality of piezoelectric portions 311 and the flexible portion 313. For example, the piezoelectric composite layer 310 may have a quadrilateral shape, but is not limited thereto, and may have a circular shape, an elliptical shape, or a polygonal shape. Each of the plurality of piezoelectric portions 311 may include a polygonal pattern. For example, the plurality of piezoelectric portions 311 may include a line pattern having a certain first width W1, may be spaced apart from each other in the first direction X, and may be parallel in the second direction Y.

[0130] At least one of the plurality of piezoelectric parts 311 according to the embodiment may have different sizes. The size of each of the plurality of piezoelectric parts 311 may be defined as one of length, width, thickness, area and volume. For example, some of the plurality of piezoelectric parts 311 may have the same size within a process error range (or an allowable error range or tolerance) occurring in the manufacturing process, and other piezoelectric parts 311 may have different sizes. In another example embodiment, the plurality of piezoelectric parts 311 may have different sizes. For example, at least one of the plurality of piezoelectric parts 311 may have different lengths, different widths or different thicknesses.

[0131] According to another embodiment, at least one of the plurality of piezoelectric portions 311 may have a different vibration frequency. For example, some of the plurality of piezoelectric portions 311 may have the same vibration frequency, while other piezoelectric portions 311 may have different vibration frequencies. In another example embodiment, the plurality of piezoelectric portions 311 may have different vibration frequencies, respectively.

[0132] The plurality of piezoelectric portions 311 may have a horizontally symmetrical structure with respect to a first central portion CP1 (or a center line in a width direction) of the piezoelectric composite layer 310 in the first direction X. Each of the plurality of piezoelectric portions 311 according to an embodiment may have a size that increases in a direction from the end portions EP1 and EP2 in the first direction X of the piezoelectric composite layer 310 to the first central portion CP1. Therefore, the plurality of piezoelectric portions 311 may have various vibration frequencies corresponding to various sizes (or size gradients).

[0133] Each of the plurality of piezoelectric portions 311 may vibrate in a vibration mode of displacement (or direction) of d31. For example, the vibration frequency of each of the piezoelectric portions 311 may be inversely proportional to the weight (or mass), and therefore, may be increased or decreased based on the length of the corresponding piezoelectric portion 311 or based on the weight. For example, when the length of each piezoelectric portion 311 decreases, the vibration frequency of each piezoelectric portion 311 may increase due to the decrease in weight. When the length of each piezoelectric portion 311 increases, the vibration frequency of each piezoelectric portion 311 may decrease due to the increase in weight.

[0134] In another example embodiment, the resonant frequency of each piezoelectric portion 311 may be adjusted based on the length or stiffness, and may be increased or decreased based on the length. For example, when the length of each piezoelectric portion 311 is reduced, the main resonant frequency of each piezoelectric portion 311 may increase due to the weight reduction, and when the length of each piezoelectric portion 311 is increased, the main resonant frequency of each piezoelectric portion 311 may decrease due to the increase in length. For example, when the length L of each piezoelectric portion 311 is 50 mm, the wavelength (λ) is 100 nm, and the acoustic wave velocity (υ) is 1,000 m / s, the main resonant frequency (f1=υ / λ) (λ=2L) of each piezoelectric portion 311 may be about 10 kHz, and when the length L of each piezoelectric portion 311 is reduced to 25 mm, the main resonant frequency (f1) of each piezoelectric portion 311 may increase to about 20 kHz.

[0135] Since each of the plurality of piezoelectric portions 311 according to the embodiment has a size that increases in a direction from the end portions EP1 and EP2 of the piezoelectric composite layer 310 to the first central portion CP1, the piezoelectric composite layer 310 according to the embodiment may have various vibration frequencies. Therefore, the sound pressure planarization (or flatness) characteristics and the sound pressure characteristics generated based on the vibration of the display panel 100 may increase and the sound pressure reproduction band may be expanded.

[0136] In some example embodiments, the piezoelectric composite layer 310 may include first to Nth piezoelectric portions 311[1] to 311[N] (where N is an odd number equal to or greater than 5). The i+1th (where i is (N-1) / 2) piezoelectric portion 311[i+1] may be in a first central portion CP1 of the piezoelectric composite layer 310. The first to 311[i] piezoelectric portions may be disposed on a first side S1 between one end EP1 of the piezoelectric composite layer 310 and the first central portion CP1. The i+2nd to Nth piezoelectric portions 311[i+2] to 311[N] piezoelectric portions may be disposed on a second side S2 between another end EP2 of the piezoelectric composite layer 310 opposite to the one end EP1 and the first central portion CP1. The piezoelectric portions other than the i+1th piezoelectric portion 311[i+1] among the first to Nth piezoelectric portions 311[1] to 311[N] may have a vertically asymmetric structure with respect to the second central portion CP2 (or the center line in the length direction) of the piezoelectric composite layer 310 in the second direction Y. Therefore, one end of the piezoelectric portions other than the i+1th piezoelectric portion 311[i+1] among the first to Nth piezoelectric portions 311[1] to 311[N] may be spaced apart from one side (or the upper side) of the piezoelectric composite layer 310 parallel to the first direction X.

[0137] According to an embodiment, the first to N-th piezoelectric portions 311 may have the same width W1 and thickness H1 (height) within a process error range (or an allowable error range or tolerance) occurring in a manufacturing process. The i+1-th piezoelectric portion 311[i+1] may have the largest length among the lengths of the piezoelectric portions 311, and, for example, may have a first length L1 corresponding to a longitudinal length of the piezoelectric composite layer 310 parallel to the second direction Y. Each of the first piezoelectric portion 311[1] and the N-th piezoelectric portion 311[N] may be disposed closest to an end of the piezoelectric composite layer 310, and may have the smallest length among the lengths of the piezoelectric portions 311, and, for example, may have a second length L2 shorter than the first length L1 of the i+1-th piezoelectric portion 311[i+1].

[0138] The second piezoelectric portion 311[2] to the i-th piezoelectric portion 311[i] may have different lengths within the range of being longer than the first piezoelectric portion 311[1] and shorter than the i+1-th piezoelectric portion 311[i+1], and may have a longer length as it is closer to the i+1-th piezoelectric portion 311[i+1]. The i+2-th piezoelectric portion 311[i+2] to the N-1-th piezoelectric portion 311[N-1] may have different lengths within the range of being longer than the N-th piezoelectric portion 311[N] and shorter than the i+1-th piezoelectric portion 311[i+1], and may have a longer length as it is closer to the i+1-th piezoelectric portion 311[i+1]. Therefore, the first piezoelectric portion 311[1] to the i+1th piezoelectric portion 311[i+1] may have different vibration frequencies based on different sizes (or lengths), and the i+2th piezoelectric portion 311[i+2] to the Nth piezoelectric portion 311[N] may have different vibration frequencies based on different sizes (or lengths). The piezoelectric portions having a horizontally symmetrical structure with respect to the i+1th piezoelectric portion 311[i+1] among the first piezoelectric portion 311[1] to the Nth piezoelectric portion 311[N] may have the same vibration frequency.

[0139] A plurality of piezoelectric parts 311 according to an embodiment may be divided into a plurality of groups (or piezoelectric groups). These plurality of groups may include the same or different number of piezoelectric parts 311. The piezoelectric parts 311 in the same group may have the same size within the process error range (or allowable error range or tolerance) that occurs in the manufacturing process. A plurality of piezoelectric parts 311 may have different sizes in groups. For example, a plurality of piezoelectric parts 311 may have the same width and thickness (or height) within the process error range (or allowable error range or tolerance) that occurs in the manufacturing process, and may have different lengths in groups. Therefore, these plurality of groups may have different vibration frequencies.

[0140] According to an embodiment, each of the plurality of groups may include two or more of the plurality of piezoelectric portions 311. The two or more piezoelectric portions 311 in each group may be disposed adjacent to each other, or may have a horizontally symmetrical structure with respect to the first central portion CP1 of the piezoelectric composite layer 310. The piezoelectric portions of the groups other than the group in the first central portion CP1 of the piezoelectric composite layer 310 may have a vertically asymmetrical structure with respect to the second central portion CP2 of the piezoelectric composite layer 310.

[0141] For example, Figure 3 When the piezoelectric composite layer 310 includes the first piezoelectric portion 311[1] to the seventeenth piezoelectric portion 311[N], the seventeen piezoelectric portions 311[1] to 311[N] may be divided into the first to ninth groups. The first group may include one piezoelectric portion in the first central portion CP1 of the piezoelectric composite layer 310, each of the second to ninth groups may include two piezoelectric portions, and the two piezoelectric portions in each of the second to ninth groups may be in a horizontally symmetrical structure with respect to the first central portion CP1 of the piezoelectric composite layer 310. For example, the first group may include the ninth piezoelectric portion 311[i+1] in the first central portion CP1 of the piezoelectric composite layer 310, the second group may include the eighth piezoelectric portion 311[i] and the tenth piezoelectric portion 311[i+2] closest to the first group, and the ninth group may include the first piezoelectric portion 311[1] closest to one end EP1 of the piezoelectric composite layer 310 and the seventeenth piezoelectric portion 311[N] closest to the other end EP2 of the piezoelectric composite layer 310. Therefore, since the piezoelectric portions 311 have different sizes, the first to ninth groups may have different vibration frequencies, and the vibration frequencies of the groups may be horizontally symmetric with respect to the first central portion CP1 of the piezoelectric composite layer 310 .

[0142] Each of the plurality of piezoelectric parts 311 according to the embodiment may include an inorganic material or a piezoelectric material, each of which vibrates based on a piezoelectric effect (or piezoelectric characteristics) caused by an electric field. For example, each of the plurality of piezoelectric parts 311 may be referred to as an active part, an inorganic material part, a piezoelectric material part, or a vibration part, but is not limited thereto.

[0143] Each of the plurality of piezoelectric parts 311 may be formed of a ceramic material for generating relatively high vibrations, or may be formed of a piezoelectric ceramic having a perovskite-based crystal structure. For example, the inorganic material portion in each of the plurality of piezoelectric parts 311 may include one or more materials of lead (Pb), zirconium (Zr), titanium (Ti), zinc (Zn), nickel (Ni), manganese (Mn), and niobium (Nb), but is not limited thereto. In another example embodiment, the inorganic material portion in each of the plurality of piezoelectric parts 311 may include a lead zirconate titanate (PZT)-based material containing lead (Pb), zirconium (Zr), and titanium (Ti), or may include a lead zirconate nickel niobate (PZNN)-based material containing lead (Pb), zinc (Zn), nickel (Ni), and niobium (Nb), but is not limited thereto. The inorganic material portion may include at least one of CaTiO3, BaTiO3, and SrTiO3, each of which does not contain Pb, but is not limited thereto. The plurality of piezoelectric portions 311 having such a configuration may alternately contract and expand based on the inverse piezoelectric effect based on a signal applied thereto. Therefore, the plurality of piezoelectric portions 311 may vibrate based on a vibration mode (or bending phenomenon) of d31 displacement.

[0144] The flexible portion 313 may provide flexibility to the piezoelectric composite layer 310 and may form the overall shape of the piezoelectric composite layer 310. The flexible portion 313 according to an embodiment may be disposed between the plurality of piezoelectric portions 311 and may be connected to the piezoelectric portion 311 adjacent thereto, so that the piezoelectric composite layer 310 can have various shapes. For example, the flexible portion 313 may surround or cover at least three or four outer surfaces (or side walls) of each of the plurality of piezoelectric portions 311.

[0145] The flexible portion 313 according to the embodiment may have a modulus and viscoelasticity lower than the modulus and viscoelasticity of each piezoelectric portion 311. This can enhance the reliability of each piezoelectric portion 311 that is susceptible to impact due to brittle characteristics. For example, when the flexible vibration module 300 used to vibrate the display panel 100 has impact resistance and high rigidity, the flexible vibration module 300 may have maximum vibration characteristics. In order to make the flexible vibration module 300 have impact resistance and high rigidity, the flexible portion 313 may include a material having a relatively high damping factor (tan δ) and a relatively high rigidity. For example, the flexible portion 313 may include a material having a damping factor (tan δ) of about 0.1 Gpa to about 1 Gpa and a relatively high rigidity of about 0 Gpa to about 10 Gpa. The damping factor (tan δ) and rigidity characteristics can be described based on the correlation between the loss factor and the modulus. The flexible portion 313 may include a material having a loss factor of about 0.01 to about 1 and a modulus of about 1 Gpa to about 10 Gpa.

[0146] The flexible portion 313 may include an organic material or an organic polymer each having a flexible property compared to the piezoelectric portion 311. For example, the flexible portion 313 may include an organic material, an organic polymer, an organic piezoelectric material, or an organic non-piezoelectric material. For example, the flexible portion 313 may be referred to as an organic material portion, an adhesive portion, an elastic portion, a bending portion, or a damping portion, but is not limited thereto. The flexible portion 313 according to an embodiment may include at least one of an organic piezoelectric material and an organic non-piezoelectric material. Therefore, the flexible portion 313 may absorb the impact applied to the piezoelectric portion 311, thereby enhancing the overall durability of the flexible vibration module 300. The organic piezoelectric material included in the flexible portion 313 may be an organic material having an electroactive property. For example, the organic piezoelectric material may include at least one of polyvinylidene fluoride (PVDF), β-polyvinylidene fluoride (β-PVDF), polyvinyl trifluoroethylene (PVDF-TrFE), and polyvinyl trifluoroethylene-chlorofluoroethylene (PVDF-TrFE-CFE), but is not limited thereto.

[0147] The organic non-piezoelectric material in the flexible portion 313 may include a curable resin component and an adhesive including the curable resin component. For example, the organic non-piezoelectric material may include at least one of an epoxy-based polymer, an acrylic-based polymer, and a silicon-based polymer, but is not limited thereto. The flexible portion 313 according to an embodiment may include a plurality of flexible patterns 313a and flexible dummy patterns 313b.

[0148] Each of the plurality of flexible patterns 313a may be configured to fill a gap region between the plurality of piezoelectric portions 311 of the piezoelectric composite layer 310. For example, the plurality of flexible patterns 313a may each be disposed between two adjacent piezoelectric portions of the plurality of piezoelectric portions 311 that are parallel to the second direction Y and spaced apart from each other by a certain interval or distance in the first direction X. Therefore, each may be a line pattern having a second width W2 corresponding to the interval or distance between the plurality of piezoelectric portions 311.

[0149] According to an embodiment, the plurality of flexible patterns 313a may each have the same second width W2 within a process error range (or an allowable error range or tolerance) occurring in a manufacturing process. The second width W2 of each of the plurality of flexible patterns 313a may be the same as or different from the first width W1 of each piezoelectric portion 311. The size of each of the plurality of flexible patterns 313a may be adjusted based on a desired condition of at least one of the vibration characteristics, flexibility, and size of the flexible vibration module 300. For example, in a display device or a flexible vibration module 300 having piezoelectric characteristics but not flexibility, the first width W1 of each piezoelectric portion 311 may be adjusted to be greater than the second width W2 of each of the plurality of flexible patterns 313a.

[0150] In another example embodiment, in a display device or a flexible vibration module 300 having flexible rather than piezoelectric characteristics, the first width W1 of each piezoelectric portion 311 may be adjusted to be smaller than the second width W2 of each of the plurality of flexible patterns 313a. Therefore, the size of the piezoelectric composite layer 310 may be adjusted based on the characteristics required by the display device, and thus, the piezoelectric composite layer 310 may be easily designed.

[0151] The flexible dummy pattern 313b may be in a dummy region where the plurality of flexible patterns 313a and the plurality of piezoelectric portions 311 in the piezoelectric composite layer 310 are not disposed. The flexible dummy pattern 313b may form a shape other than the shape where the piezoelectric portion 311 and the flexible pattern 313a are disposed in the overall shape of the flexible vibration module 300.

[0152] The flexible dummy pattern 313b according to the embodiment may be configured to fill a dummy region (or a region in which the piezoelectric portion is not provided) occurring at a corner of each of the first side S1 and the second side S2 of the piezoelectric composite layer 310 based on a length gradient of each of the plurality of piezoelectric portions 311. The flexible dummy pattern 313b may be connected to one side surface of each of the plurality of flexible patterns 313a. For example, each of the plurality of flexible patterns 313a may have a finger-like structure extending from the flexible dummy pattern 313b to a space between the plurality of piezoelectric portions 311.

[0153] In some example embodiments, the piezoelectric composite layer 310 may have a quadrilateral shape based on a plurality of piezoelectric portions 311, a plurality of flexible patterns 313a, and a flexible dummy pattern 313b, each disposed in the same plane, but is not limited thereto. In other example embodiments, the piezoelectric composite layer 310 may have a circular shape, an elliptical shape, a triangular shape, or a pentagonal or more polygonal shape. For example, the piezoelectric composite layer 310 may have a pentagonal or more polygonal shape, and the piezoelectric composite layer 310 may be a vibration source (or vibrator or vibrating body) having a substantially circular shape, thereby enhancing vibration characteristics.

[0154] In the piezoelectric composite layer 310, the piezoelectric portion 311 and the flexible pattern 313a of the flexible portion 313 may be alternately repeated and connected to each other, and thus the piezoelectric composite layer 310 may have a thin film type. Therefore, the piezoelectric composite layer 310 may be bent based on the shape of the display panel 100, and may have a size corresponding to the display panel 100 or may have a size for realizing vibration characteristics or sound characteristics each adjusted based on the vibration of the display panel 100.

[0155] The first electrode layer 320 may be disposed on the first surface (or rear surface) of the piezoelectric composite layer 310 and may be electrically connected to the first surface of each of the plurality of piezoelectric portions 311. The first electrode layer 320 according to an embodiment may include a transparent conductive material, a semi-transparent conductive material, or an opaque conductive material. For example, examples of transparent conductive materials or semi-transparent conductive materials may include indium tin oxide (ITO) or indium zinc oxide (IZO), but are not limited thereto. Examples of opaque conductive materials may include aluminum (Al), copper (Cu), gold (Au), silver (Ag), molybdenum (Mo), and magnesium (Mg) or alloys thereof, but are not limited thereto.

[0156] The second electrode layer 330 may be disposed on a second surface (or front surface) of the piezoelectric composite layer 310 opposite to the first surface, and may be electrically connected to the second surface of each of the plurality of piezoelectric portions 311. The second electrode layer 330 according to an embodiment may include a transparent conductive material, a semi-transparent conductive material, or an opaque conductive material. For example, the second electrode layer 330 may include the same material as the first electrode layer 320.

[0157] The piezoelectric composite layer 310 may be polarized by applying a certain voltage to the first electrode layer 320 and the second electrode layer 330 in a certain temperature atmosphere or a temperature atmosphere changed from high temperature to room temperature. The polarization direction of each of the plurality of piezoelectric portions 311 may be adjusted based on the voltage applied to the first electrode layer 320 and the second electrode layer 330.

[0158] The flexible vibration module 300 according to the embodiment of the present disclosure may further include a first protective film 340 and a second protective film 350. The first protective film 340 may be on the first electrode layer 320 and may protect the first surface of the first electrode layer 320 or the piezoelectric composite layer 310. For example, the first protective film 340 may be a polyimide (PI) film or a polyethylene terephthalate (PET) film, but is not limited thereto. The second protective film 350 may be on the second electrode layer 330 and may protect the second surface of the second electrode layer 330 or the piezoelectric composite layer 310. For example, the second protective film 350 may be a polyimide (PI) film or a polyethylene terephthalate (PET) film, but is not limited thereto.

[0159] In another exemplary embodiment, in the flexible vibration module 300, the arrangement structure of the piezoelectric portion 311 is not limited to Figure 3The arrangement structure illustrated in . The arrangement structure can be changed into various structures based on the required conditions of at least one of the vibration characteristics, flexibility and size of the flexible vibration module 300. For example, the length gradient or vibration frequency of each of the piezoelectric parts 311 may not be adjusted to gradually increase in the direction from the end EP1 and EP2 of the piezoelectric composite layer 310 to the first central part CP1. In another example embodiment, the length gradient or vibration frequency of each of the piezoelectric parts 311 may be adjusted to change randomly, or may be adjusted to gradually increase or randomly change in the direction from the end EP1 to the end EP2 of the piezoelectric composite layer 310.

[0160] The flexible vibration module 300 according to the first embodiment of the present disclosure can vibrate the display panel 100 based on the bending caused by the inverse piezoelectric effect based on the signal applied to each of the plurality of piezoelectric portions 311, thereby providing sound or tactile feedback to the user. The flexible portion 313 filled or disposed between the plurality of piezoelectric portions 311 may have flexibility. Therefore, even when the piezoelectric composite layer 310 is bent, the piezoelectric portion 311 is not damaged or its performance is not reduced.

[0161] The flexible vibration module 300 according to the first embodiment of the present disclosure may be disposed on the rear surface of the display panel 100 so that the display panel 100 fully vibrates in the vertical direction (or the front-rear direction), thereby outputting the desired sound to the front area in front of the display device. The piezoelectric portion 311 and the flexible portion 313 may each be configured with a piezoelectric composite layer 310 so as to be implemented in a pattern shape. Therefore, the piezoelectric composite layer 310 may have a size corresponding to the display panel 100, whereby the panel coverage (or contact area) of the flexible vibration module 300 contacting the display panel 100 may be increased to enhance the sound characteristics based on the vibration of the display panel 100. For example, the flexible vibration module 300 may be configured to have a wide area corresponding to the same size as the size of the display panel 100. Therefore, the sound pressure characteristics of the low-pitched vocal cords, which are the disadvantages of the film-type piezoelectric, may be improved and the driving voltage may be reduced. The flexible vibration module 300 according to the embodiment of the present disclosure may include an inorganic material portion and an organic material portion, and may be a thin film type. Therefore, the flexible vibration module 300 may be integrated into or equipped in the display device without interference caused by mechanical elements and / or other elements constituting the display device.

[0162] The flexible vibration module 300 according to the first embodiment of the present disclosure may have various vibration frequencies based on the size gradient of each of the plurality of piezoelectric portions 311. Therefore, the flexible vibration module 300 may vibrate the display panel 100 using vibrations having various vibration frequencies through an electric field based on a signal applied to each of the plurality of piezoelectric portions 311. Therefore, the sound pressure flattening (or flatness) characteristics and the sound pressure characteristics of the sound generated based on the vibration of the display panel 100 may be increased, and the sound reproduction band may be expanded.

[0163] Figure 5 The flexible vibration module 300 according to the second embodiment of the present disclosure is illustrated, and the flexible vibration module 300 according to the second embodiment of the present disclosure is illustrated. Figure 3 The embodiment is realized by arranging the piezoelectric part in the piezoelectric composite layer as illustrated in FIG. Figure 5 As illustrated, the piezoelectric composite layer 310 may include a plurality of piezoelectric portions 311 and a flexible portion 313 disposed between the plurality of piezoelectric portions 311 .

[0164] The plurality of piezoelectric portions 311 may have a horizontally symmetrical structure with respect to the first central portion CP1 of the piezoelectric composite layer 310 in the first direction X. Each of the plurality of piezoelectric portions 311 may have a size that is gradually reduced in a direction from the end portions EP1 and EP2 in the first direction X of the piezoelectric composite layer 310 to the first central portion CP1, and thus may have various vibration frequencies corresponding to various sizes (or size gradients). However, each of the plurality of piezoelectric portions 311 is gradually reduced in a direction from the end portions EP1 and EP2 of the piezoelectric composite layer 310 to the first central portion CP1.

[0165] The flexible portion 313 may provide flexibility to the piezoelectric composite layer 310 and may form the overall shape of the piezoelectric composite layer 310. The flexible portion 313 according to an embodiment may be disposed between a plurality of piezoelectric portions 311 and may be connected to a piezoelectric portion 311 adjacent thereto so that the piezoelectric composite layer 310 can have various shapes. For example, the flexible portion 313 may surround or cover at least three or four outer surfaces (or side walls) of each of the plurality of piezoelectric portions 311. The flexible portion 313 may include: a plurality of flexible patterns 313a, each of the plurality of flexible patterns 313a being configured to fill a gap region between the plurality of piezoelectric portions 311; and a flexible dummy pattern 313b, the flexible dummy pattern 313b being in a dummy region in which the plurality of piezoelectric portions 311 and the plurality of flexible patterns 313a are not disposed. In addition Figure 3 and Figure 4 In addition to the arrangement position of the flexible portion illustrated in each of the examples, the flexible portion 313 and Figure 3 and Figure 4 The flexible portion illustrated in each of the examples is the same.

[0166] The flexible vibration module 300 according to the second embodiment of the present disclosure can make the display panel 100 vibrate at various vibration frequencies based on the size gradient (or length gradient) of each of the plurality of piezoelectric parts 311. Therefore, the sound pressure flattening (or flatness) characteristics and the sound pressure characteristics of the sound generated based on the vibration of the display panel 100 can be increased and the sound reproduction band can be expanded. For example, in the flexible vibration module 300 according to the second embodiment of the present disclosure, the piezoelectric part 311 having a relatively low vibration frequency (or low resonance frequency) due to a relatively large size can be adjacent to the end portions EP1 and EP2 of each of the piezoelectric parts 311. Therefore, the vibration area of ​​the display panel 100 that vibrates through the piezoelectric part 311 can be expanded, and therefore, the sound of the low-pitched vocal band can be improved. Therefore, the vibration area of ​​the display panel 100 that produces a sufficient low-pitched vocal band can be used as widely as possible.

[0167] Figure 6 The flexible vibration module 300 according to the third embodiment of the present disclosure is illustrated, and the flexible vibration module 300 according to the third embodiment of the present disclosure is illustrated. Figure 3 The embodiment is realized by arranging the piezoelectric part in the piezoelectric composite layer as illustrated in FIG. Figure 6 As illustrated, in the flexible vibration module 300 according to the third embodiment of the present disclosure, the piezoelectric composite layer 310 may include a plurality of piezoelectric portions 311 and a flexible portion 313 between the plurality of piezoelectric portions 311. Each of the plurality of piezoelectric portions 311 may have a size that gradually increases in a direction from the ends EP1 and EP2 in the first direction X of the piezoelectric composite layer 310 to the first central portion CP1, and thus may have various vibration frequencies corresponding to various sizes. The central portion in the length direction of each of the plurality of piezoelectric portions 311 parallel to the second direction Y may be in the second central portion CP2 of the piezoelectric composite layer 310. Both ends of the piezoelectric portion of the piezoelectric composite layer 310 other than the piezoelectric portion in the first central portion CP1 may be spaced apart from both sides (or the upper and lower sides) of the piezoelectric composite layer 310 parallel to the first direction X. Each of the plurality of piezoelectric portions 311 may have a size that gradually increases in a direction from the end portions EP1 and EP2 in the first direction X of the piezoelectric composite layer 310 to the first central portion CP1, and thus may have various vibration frequencies corresponding to various sizes (or size gradients). In addition to the plurality of piezoelectric portions 311 being horizontally symmetrical with respect to the first central portion CP1 of the piezoelectric composite layer 310 and being vertically symmetrical with respect to the second central portion CP2 of the piezoelectric composite layer 310, the plurality of piezoelectric portions 311 and Figure 3 and Figure 4 The same, so the detailed description thereof is omitted.

[0168] The flexible portion 313 may provide flexibility to the piezoelectric composite layer 310 and may form the overall shape of the piezoelectric composite layer 310. The flexible portion 313 according to an embodiment may be between a plurality of piezoelectric portions 311 and may be connected to a piezoelectric portion 311 adjacent thereto so that the piezoelectric composite layer 310 can have various shapes. For example, the flexible portion 313 may surround or cover all of the four outer surfaces (or side walls) of each of the plurality of piezoelectric portions 311. The flexible portion 313 may include: a plurality of flexible patterns 313a, each of the plurality of flexible patterns 313a being configured to fill a gap region between the plurality of piezoelectric portions 311; and a flexible dummy pattern 313b, the flexible dummy pattern 313b being in a dummy region in which the plurality of piezoelectric portions 311 and the plurality of flexible patterns 313a are not provided. In addition Figure 3 and Figure 4 In addition to the arrangement position of the flexible portion illustrated in each of the examples, the flexible portion 313 and Figure 3 and Figure 4 The flexible portion 313 is the same as that illustrated in each of the flexible portions 313, and therefore, a detailed description of the flexible portion 313 is omitted. In the flexible vibration module 300 according to the present embodiment, each of the plurality of piezoelectric portions 311 may have a size that is gradually reduced in a direction from the end portions EP1 and EP2 in the first direction X of the piezoelectric composite layer 310 to the first central portion CP1.

[0169] In the flexible vibration module 300 according to the third embodiment, the arrangement structure of the piezoelectric portion 311 is not limited to Figure 6 In this example embodiment, the flexible vibration module 300 may be changed into various structures based on the required conditions of at least one of the vibration characteristics, flexibility and size of the flexible vibration module 300. For example, the length gradient or vibration frequency of each of the piezoelectric portions 311 may not be adjusted to gradually increase in the direction from the end portions EP1 and EP2 of the piezoelectric composite layer 310 to the first central portion CP1 and may be adjusted to randomly change, or may be adjusted to gradually increase or randomly change in the direction from the end portion EP1 to the end portion EP2 of the piezoelectric composite layer 310.

[0170] Figure 7 A flexible vibration module 300 according to a fourth embodiment of the present disclosure is illustrated, and Figure 8 It is along Figure 7 A cross-sectional view taken along line III-III' illustrated in FIG. Figure 7 and Figure 8 Illustrated by modifying Figure 3 The embodiment is realized by the structure of the piezoelectric composite layer illustrated in FIG. Figure 7 and Figure 8As illustrated, in the flexible vibration module 300 according to the fourth embodiment of the present disclosure, the piezoelectric composite layer 310 may include a plurality of piezoelectric portions 311 and a flexible portion 313 between the plurality of piezoelectric portions 311. The plurality of piezoelectric portions 311 may include a polygonal pattern. For example, the plurality of piezoelectric portions 311 may include a line pattern having a first length L1, may be spaced apart from each other in the first direction X, and may be parallel in the second direction Y.

[0171] Some of the plurality of piezoelectric parts 311 according to the embodiment may have different sizes. The size of each of the plurality of piezoelectric parts 311 may be defined as one of length, width, thickness, area, and volume. For example, some of the plurality of piezoelectric parts 311 may have the same size within a process error range (or allowable error range or tolerance) occurring in the manufacturing process, and the other piezoelectric parts 311 may have different sizes, respectively.

[0172] The plurality of piezoelectric portions 311 may have a horizontally symmetrical structure with respect to the first central portion CP1 of the piezoelectric composite layer 310, and may have a vertically symmetrical structure with respect to the second central portion CP2 of the piezoelectric composite layer 310. Each of the plurality of piezoelectric portions 311 may have a size that gradually increases in a direction from the end portions EP1 and EP2 in the first direction X of the piezoelectric composite layer 310 to the first central portion CP1, and thus may have various vibration frequencies corresponding to various sizes (or width gradients).

[0173] Each of the plurality of piezoelectric portions 311 according to the present embodiment may vibrate in a vibration mode of displacement (or direction) of d31. Each of the vibration frequency and the resonance frequency of each of the piezoelectric portions 311 may increase as its width decreases in the first direction X. The piezoelectric composite layer 310 according to the embodiment may include a first piezoelectric portion 311[1] to an Nth piezoelectric portion 311[N] (where N is an odd number equal to or greater than 5). The i+1th (where i is (N-1) / 2) piezoelectric portion 311[i+1] may be in the first central portion CP1 of the piezoelectric composite layer 310. The first piezoelectric portion 311[1] to the i-th piezoelectric portion 311[i] may be disposed on a first side S1 between one end EP1 of the piezoelectric composite layer 310 and the first central portion CP1. The (i+2)th to (N)th piezoelectric portions 311 [i+2]th to (N)th piezoelectric portions 311 [N] may be disposed at a second side S2 between the other end portion EP2 of the piezoelectric composite layer 310 opposite to the one end portion EP1 and the first central portion CP1.

[0174] According to an embodiment, the first to Nth piezoelectric portions 311 may have the same length L1 and thickness H1 (or height) within a process error range (or an allowable error range or tolerance) occurring in a manufacturing process. The i+1th piezoelectric portion 311[i+1] may have the widest width W3 among the widths of the piezoelectric portion 311. Each of the first piezoelectric portion 311[1] and the Nth piezoelectric portion 311[N] may be disposed closest to an end of the piezoelectric composite layer 310, and may have the narrowest width W4 among the widths of the piezoelectric portion 311. The second piezoelectric portion 311[2] to the i-th piezoelectric portion 311[i] may have different widths within a range wider than the first piezoelectric portion 311[1] and narrower than the i+1th piezoelectric portion 311[i+1], and may have a wider width as it approaches the i+1th piezoelectric portion 311[i+1]. The i+2nd piezoelectric portion 311[i+2] to the N-1st piezoelectric portion 311[N-1] may have different widths within a range wider than the Nth piezoelectric portion 311[N] and narrower than the i+1st piezoelectric portion 311[i+1], and may have a wider width as it approaches the i+1st piezoelectric portion 311[i+1]. Therefore, the first piezoelectric portion 311[1] to the i+1st piezoelectric portion 311[i+1] may have different vibration frequencies based on the corresponding different widths, and the i+2nd piezoelectric portion 311[i+2] to the Nth piezoelectric portion 311[N] may have different vibration frequencies based on the respectively different widths. The piezoelectric portions having a horizontally symmetrical structure with respect to the i+1st piezoelectric portion 311[i+1] among the first piezoelectric portion 311[1] to the Nth piezoelectric portion 311[N] may have the same vibration frequency.

[0175] According to the embodiment, a plurality of piezoelectric parts 311 can be divided into a plurality of groups (or piezoelectric groups). These plurality of groups can include the same or different piezoelectric parts 311. The piezoelectric parts 311 in the same group can have the same size within the process error range (or allowable error range or tolerance) occurring in the manufacturing process. A plurality of piezoelectric parts 311 can have different sizes in groups. For example, a plurality of piezoelectric parts 311 can have the same width and thickness (or height) within the process error range (or allowable error range or tolerance) occurring in the manufacturing process, and can have different lengths in groups. Therefore, these plurality of groups can have different vibration frequencies respectively.

[0176] According to an embodiment, each of the plurality of groups may include two or more of the plurality of piezoelectric portions 311, and the two or more piezoelectric portions 311 in each group may be disposed adjacent to each other, or may be in a horizontally symmetrical structure with respect to the first central portion CP1 of the piezoelectric composite layer 310. Figure 7Similarly, when the piezoelectric composite layer 310 includes the first to seventeenth piezoelectric portions 311 [ 1 ] to 311 [N], the seventeen piezoelectric portions 311 [ 1 ] to 311 [N] may be divided into first to ninth groups.

[0177] The first group may include one piezoelectric portion 311[i+1] in the first central portion CP1 of the piezoelectric composite layer 310. Each of the second to ninth groups may include two piezoelectric portions. The two piezoelectric portions in each of the second to ninth groups may be in a horizontally symmetrical structure with respect to the first central portion CP1 of the piezoelectric composite layer 310. For example, the first group may include the ninth piezoelectric portion 311[i+1] having the widest width W3 and in the first central portion CP1 of the piezoelectric composite layer 310. The second group may include the eighth piezoelectric portion 311[i] and the tenth piezoelectric portion 311[i+2] closest to the first group. The ninth group may include the first piezoelectric portion 311[1] closest to one end EP1 of the piezoelectric composite layer 310 and the seventeenth piezoelectric portion 311[N] closest to the other end EP2 of the piezoelectric composite layer 310. The first piezoelectric portion 311[1] and the seventeenth piezoelectric portion 311[N] may have the narrowest width W4 among the widths of the piezoelectric portions 311. Therefore, since the piezoelectric portions 311 have different widths, respectively, the first to ninth groups may have different vibration frequencies, and the vibration frequencies of the groups may be horizontally symmetrical with respect to the first central portion CP1 of the piezoelectric composite layer 310 .

[0178] The flexible portion 313 may include a plurality of flexible patterns 313a, each between the plurality of piezoelectric portions 311. The plurality of flexible patterns 313a may each be between two adjacent piezoelectric portions in the plurality of piezoelectric portions 311, and may improve the impact resistance of the piezoelectric portion 311 and may provide flexibility for the flexible vibration module 300. The plurality of flexible patterns 313a and the plurality of piezoelectric portions 311 may be alternately disposed (or arranged) on the same plane (or the same layer). Each of the plurality of flexible patterns 313a may be configured to fill a gap between two adjacent piezoelectric portions in the plurality of piezoelectric portions 311, and may be connected to or attached to the piezoelectric portion 311 adjacent thereto. For example, the plurality of flexible patterns 313a may have a line pattern having a width W5 corresponding to the gap between the two adjacent piezoelectric portions 311.

[0179] The plurality of flexible patterns 313a may each have the same size within a process error range (or an allowable error range or tolerance) occurring in the manufacturing process, and may have a width, an area, or a volume, for example. However, the present embodiment is not limited thereto, and the plurality of flexible patterns 313a may have different sizes, or may have sizes corresponding to the sizes of two adjacent piezoelectric portions 311. Therefore, the size of each of the plurality of flexible patterns 313a may be adjusted based on the required conditions of at least one of the vibration characteristics, flexibility, and size of the flexible vibration module 300. For example, in a display device or a flexible vibration module 300 that requires piezoelectric characteristics rather than flexibility, the width W5 of each flexible pattern 313a may be relatively reduced. In another exemplary embodiment, in a display device or a flexible vibration module 300 that requires flexibility rather than piezoelectric characteristics, the width W5 of each flexible pattern 313a may be relatively increased. Therefore, the size of the piezoelectric composite layer 310 may be adjusted based on the characteristics required by the display device, and therefore, the piezoelectric composite layer 310 may be easily designed.

[0180] In the flexible vibration module 300 according to the present embodiment, the plurality of piezoelectric portions 311 may have a horizontally symmetrical structure relative to the first central portion CP1 of the piezoelectric composite layer 310, and a vertically symmetrical structure relative to the second central portion CP2 of the piezoelectric composite layer 310, and each may have a size that gradually decreases in a direction from the ends EP1 and EP2 in the first direction X of the piezoelectric composite layer 310 to the first central portion CP1, and therefore, the plurality of piezoelectric portions 311 may have various vibration frequencies corresponding to various sizes (or width gradients).

[0181] In the flexible vibration module 300 according to the fourth embodiment, the arrangement structure of the piezoelectric portion 311 is not limited to Figure 7 The arrangement structure illustrated in FIG. 3 may be changed into various structures based on the required conditions of at least one of the vibration characteristics, flexibility, and size of the flexible vibration module 300. For example, the width gradient or vibration frequency of each of the piezoelectric portions 311 may not be adjusted to increase stepwise in the direction from the end portions EP1 and EP2 of the piezoelectric composite layer 310 to the first central portion CP1 and may be adjusted to change randomly, or may be adjusted to increase stepwise in the direction from the end portion EP1 to the end portion EP2 of the piezoelectric composite layer 310 or change randomly.

[0182] Fig. 9 A flexible vibration module 300 according to a fifth embodiment of the present disclosure is illustrated, and Fig.10 It is along Fig. 9 A cross-sectional view taken along line IV-IV' illustrated in FIG. Fig. 9 and Fig.10 Illustrated by modifying Figure 3The embodiment is realized by the structure of the piezoelectric composite layer illustrated in FIG. Fig. 9 and Fig.10 As illustrated, in the flexible vibration module 300 according to the fifth embodiment of the present disclosure, the piezoelectric composite layer 310 may include a plurality of piezoelectric portions 311 and flexible portions 313 between the plurality of piezoelectric portions 311 .

[0183] The plurality of piezoelectric portions 311 may include polygonal patterns. For example, the plurality of piezoelectric portions 311 may include line patterns having a certain length, may be spaced apart from each other in the first direction X, and may be parallel in the second direction Y. The plurality of piezoelectric portions 311 according to the embodiment may each have the same size within a process error range (or an allowable error range or tolerance) occurring in a manufacturing process. For example, the plurality of piezoelectric portions 311 may each have the same width W6, thickness, and length. The sizes of the plurality of piezoelectric portions 311 may be horizontally symmetrical with respect to a first central portion CP1 (or a center line in the width direction) of the piezoelectric composite layer 310 in the first direction X.

[0184] The plurality of piezoelectric portions 311 may each include a lower piezoelectric portion 311 a and an upper piezoelectric portion 311 b .

[0185] The thickness (or height) of the lower piezoelectric portion 311a and the upper piezoelectric portion 311b of each of the plurality of piezoelectric portions 311 may all be different. The thickness (or height) of the lower piezoelectric portion 311a and the upper piezoelectric portion 311b may have different thickness ratios (or thickness gradients) per piezoelectric portion 311. This thickness ratio may be horizontally symmetrical with respect to the first central portion CP1 of the piezoelectric composite layer 310. For example, the respective lower piezoelectric portion 311a and the upper piezoelectric portion 311b in each piezoelectric portion 311 may have asymmetric thicknesses with respect to the central thickness (or central height).

[0186] In another example embodiment, some of the plurality of piezoelectric portions 311 may each include a lower piezoelectric portion 311a and an upper piezoelectric portion 311b each having the same thickness (or height), and the other piezoelectric portions 311 may each include a lower piezoelectric portion 311a and an upper piezoelectric portion 311b each having a different thickness (or height). For example, with respect to the first direction X, one piezoelectric portion 311[#5] disposed between one end EP1 and the first central portion CP1 of the piezoelectric composite layer 310 may include a lower piezoelectric portion 311a and an upper piezoelectric portion 311b each having the same thickness (or height). One piezoelectric portion 311[#13] disposed between the other end EP2 and the first central portion CP1 of the piezoelectric composite layer 310 may include a lower piezoelectric portion 311a and an upper piezoelectric portion 311b each having the same thickness (or height). In addition to the piezoelectric portions 311[#5] and 311[#13] including the lower piezoelectric portion 311a and the upper piezoelectric portion 311b each having the same thickness (or height), the other piezoelectric portions 311 may each include a lower piezoelectric portion 311a and an upper piezoelectric portion 311b each having a different thickness (or height).

[0187] The lower piezoelectric portion 311a of each of the plurality of piezoelectric portions 311 may have a partial thickness in the total thickness of the corresponding piezoelectric portion 311. At least one of the plurality of lower piezoelectric portions 311a may have a different thickness. For example, some of the plurality of lower piezoelectric portions 311a may have the same thickness within a process error range (or an allowable error range or tolerance) occurring in the manufacturing process, and the other lower piezoelectric portions 311a may each have a different thickness. In another example embodiment, the plurality of lower piezoelectric portions 311a may each have a different thickness.

[0188] The plurality of lower piezoelectric portions 311a may have a horizontally symmetrical structure with respect to the first central portion CP1 of the piezoelectric composite layer 310. For example, the plurality of lower piezoelectric portions 311a may be stepped between the end portions EP1 and EP2 of the piezoelectric composite layer 310 and the first central portion CP1. Each of the plurality of lower piezoelectric portions 311a may have a thickness that gradually decreases in a direction from the end portions EP1 and EP2 of the piezoelectric composite layer 310 to the first central portion CP1. Therefore, the plurality of lower piezoelectric portions 311a may each have a different vibration frequency or various vibration frequencies corresponding to various sizes (or thickness gradients).

[0189] At least two of the upper piezoelectric portions 311 b of the plurality of piezoelectric portions 311 may have different vibration frequencies. For example, the upper piezoelectric portions 311 b of the plurality of piezoelectric portions 311 may each have a different vibration frequency.

[0190] The upper piezoelectric portion 311b of each of the plurality of piezoelectric portions 311 may have a thickness obtained by subtracting the thickness of the overlapped lower piezoelectric portion 311a from the total thickness of the corresponding piezoelectric portion 311. Except for the piezoelectric portions 311[#5] and 311[#13] of the piezoelectric composite layer 310, the other piezoelectric portions may have an asymmetric thickness structure with respect to the center thickness (or center height) of the piezoelectric portion 311. For example, the plurality of upper piezoelectric portions 311b may be stepped between the end portions EP1 and EP2 of the piezoelectric composite layer 310 and the first center portion CP1. Each of the plurality of upper piezoelectric portions 311b may have a thickness that gradually increases in a direction from the end portions EP1 and EP2 of the piezoelectric composite layer 310 to the first center portion CP1. Therefore, the plurality of lower piezoelectric portions 311a may have various vibration frequencies corresponding to various sizes (or thickness gradients).

[0191] Except for the piezoelectric portions 311[#5] and 311[#13] including the lower piezoelectric portion 311a and the upper piezoelectric portion 311b each having the same thickness (or height), the other piezoelectric portions may have a vertical stacking structure. The vertical stacking structure may include the lower piezoelectric portion 311a having a relatively thick thickness and the upper piezoelectric portion 311b having a relatively thin thickness. Alternatively, based on the arrangement position between the end portions EP1 and EP2 of the piezoelectric composite layer 310 and the first central portion CP1, the vertical stacking structure may include the lower piezoelectric portion 311a having a relatively thin thickness and the upper piezoelectric portion 311b having a relatively thick thickness.

[0192] Each of the plurality of lower piezoelectric parts 311a and each of the plurality of upper piezoelectric parts 311b according to the present embodiment can vibrate in a vibration mode of displacement (or direction) of d33. Each of the vibration frequency and the resonance frequency of each of the piezoelectric parts 311 can increase as the thickness (height) decreases in the third direction Z (or thickness direction).

[0193] The plurality of piezoelectric parts 311 according to the embodiment may be divided into a plurality of groups (or piezoelectric groups). The plurality of groups may include the same or different numbers of piezoelectric parts 311. For example, the lower piezoelectric part 311a and the upper piezoelectric part 311b of each of the plurality of piezoelectric parts 311 may have the same length and width within the process error range (or allowable error range or tolerance) occurring in the manufacturing process, and may each have different sizes in units of groups. Therefore, the plurality of groups may each have different vibration frequencies.

[0194] According to example embodiments, each of the plurality of groups may include two or more of the plurality of piezoelectric portions 311. The two or more piezoelectric portions 311 in each group may be disposed adjacent to each other, or may be in a horizontally symmetrical structure with respect to the first central portion CP1 of the piezoelectric composite layer 310. Fig. 9 and Fig.10 As in the embodiment of the present invention, when the piezoelectric composite layer 310 includes the first to seventeenth piezoelectric portions 311, the seventeen piezoelectric portions 311 may be divided into first to ninth groups.

[0195] The first group may include one piezoelectric portion 311[#9] in the first central portion CP1 of the piezoelectric composite layer 310. Each of the second to ninth groups may include two piezoelectric portions, and the two piezoelectric portions in each of the second to ninth groups may be in a horizontally symmetrical structure with respect to the first central portion CP1 of the piezoelectric composite layer 310. For example, the first group may include the ninth piezoelectric portion 311[#9] in the first central portion CP1 of the piezoelectric composite layer 310. The second group may include the eighth and tenth piezoelectric portions closest to the first group, and the ninth group may include the first piezoelectric portion closest to one end EP1 of the piezoelectric composite layer 310 and the seventeenth piezoelectric portion closest to the other end EP2 of the piezoelectric composite layer 310. The piezoelectric portions 311[#5] and 311[#13] in some of the second to ninth groups may each include a lower piezoelectric portion 311a and an upper piezoelectric portion 311b each having the same thickness. Based on the arrangement position, the piezoelectric portions in other groups may each include the lower piezoelectric portion 311a and the upper piezoelectric portion 311b each having different thicknesses in units of groups. Therefore, the first to ninth groups may have different vibration frequencies due to the piezoelectric portion 311 including the lower piezoelectric portion 311a and the upper piezoelectric portion 311b each having different sizes in units of groups, and the vibration frequencies of the groups may be horizontally symmetrical with respect to the first central portion CP1 of the piezoelectric composite layer 310.

[0196] The flexible portion 313 may be between two adjacent piezoelectric portions of the plurality of piezoelectric portions 311, may improve the impact resistance of the piezoelectric portion 311, and may provide flexibility to the flexible vibration module 300. The flexible portion 313 and the plurality of piezoelectric portions 311 may be alternately disposed (or arranged) on the same plane (or the same layer). The flexible portion 313 may be configured to fill a gap between two adjacent piezoelectric portions of the plurality of piezoelectric portions 311, and may be connected to or attached to the piezoelectric portion 311 adjacent thereto. For example, the flexible portion 313 may have a line pattern having a width W6 corresponding to the gap between the two adjacent piezoelectric portions 311.

[0197] For example, each of the plurality of flexible portions between two adjacent piezoelectric portions in the plurality of piezoelectric portions 311 may each have the same size within a process error range (or an allowable error range or tolerance) occurring in a manufacturing process, and may have a width, an area, or a volume, for example. However, the present embodiment is not limited thereto, and the plurality of flexible portions 313 may have different sizes, or may have sizes corresponding to the sizes of the two adjacent piezoelectric portions 311. Therefore, the size of each of the plurality of flexible portions 313 may be adjusted based on the required conditions of at least one of the vibration characteristics, flexibility, and size of the flexible vibration module 300. For example, in a display device or a flexible vibration module 300 that requires piezoelectric characteristics instead of flexibility, the width W6 of each piezoelectric portion 311 may be adjusted to be greater than the width W7 of the flexible portion 313. In another example embodiment, in a display device or a flexible vibration module 300 that requires flexibility instead of piezoelectric characteristics, the width W6 of each piezoelectric portion 311 may be adjusted to be less than the width W7 of the flexible portion 313. Therefore, the size of the piezoelectric composite layer 310 may be adjusted based on the characteristics required for the display device, and thus, the piezoelectric composite layer 310 may be easily designed.

[0198] The flexible portion 313 according to the present embodiment may include a lower flexible portion 313a and an upper flexible portion 313b. The plurality of lower flexible portions 313a may be respectively arranged between the plurality of lower piezoelectric portions 311a of the plurality of piezoelectric portions 311. The plurality of lower flexible portions 313a and the plurality of lower piezoelectric portions 311a may be alternately arranged (or arranged) on the same plane (or the same layer). Each of the plurality of lower flexible portions 313a may be configured to fill the gap between two adjacent lower piezoelectric portions in the plurality of lower piezoelectric portions 311a, and may be connected to or attached to the lower piezoelectric portion 311a adjacent thereto. Therefore, the thickness of each of the lower flexible portions 313a may be the same as the thickness of the lower piezoelectric portion 311a adjacent thereto. Each lower flexible portion 313a and the corresponding lower piezoelectric portion 311a of each of the plurality of piezoelectric portions 311 may constitute the lower piezoelectric composite layer 310a of the piezoelectric composite layer 310.

[0199] The plurality of upper flexible portions 313b may each be disposed between the plurality of upper piezoelectric portions 311b of the plurality of piezoelectric portions 311. The plurality of upper flexible portions 313b and the plurality of upper piezoelectric portions 311b may be alternately disposed (or arranged) on the same plane (or the same layer). Each of the plurality of upper flexible portions 313b may be configured to fill the gap between two adjacent upper piezoelectric portions of the plurality of upper piezoelectric portions 311b, and may be connected to or attached to the upper piezoelectric portion 311b adjacent thereto. Therefore, the thickness of each of the upper flexible portions 313b may be the same as the thickness of the upper piezoelectric portion 311b adjacent thereto. Each upper flexible portion 313b and the corresponding upper piezoelectric portion 311b of each of the plurality of piezoelectric portions 311 may constitute an upper piezoelectric composite layer 310b of the piezoelectric composite layer 310.

[0200] In the piezoelectric composite layer 310 according to the present embodiment, the lower piezoelectric portion 311a and the upper piezoelectric portion 311b of each of the plurality of piezoelectric portions 311 may have a vertically stacked structure. Therefore, the expansion force (or tension) and the contraction force (or compression) each based on the bimorph structure can be further increased, thereby enhancing the sound pressure characteristics.

[0201] The piezoelectric composite layer 310 according to the present embodiment may further include a first counter electrode layer 360, a second counter electrode layer 370, and an insulating layer 380. The first counter electrode layer 360 may be electrically connected to the lower piezoelectric portion 311a of each of the plurality of piezoelectric portions 311. For example, the first counter electrode layer 360 may be on the lower piezoelectric composite layer 310a of the piezoelectric composite layer 310, and may be electrically connected to the lower piezoelectric portion 311a of each of the plurality of piezoelectric portions 311. The first counter electrode layer 360 may be formed of the same material as that of the first electrode layer 320. The lower piezoelectric portion 311a of each of the plurality of piezoelectric portions 311 may vibrate according to an electrical signal applied to the first electrode layer 320 and the first counter electrode layer 360.

[0202] The second counter electrode layer 370 may be electrically connected to the upper piezoelectric portion 311b of each of the plurality of piezoelectric portions 311. For example, the second counter electrode layer 370 may be on the upper piezoelectric composite layer 310b of the piezoelectric composite layer 310, and may be electrically connected to the upper piezoelectric portion 311b of each of the plurality of piezoelectric portions 311. The second counter electrode layer 370 may be formed of the same material as that of the second electrode layer 330. The upper piezoelectric portion 311b of each of the plurality of piezoelectric portions 311 may vibrate according to an electrical signal applied to the second electrode layer 330 and the second counter electrode layer 370.

[0203] The insulating layer 380 may be between the first counter electrode layer 360 and the second counter electrode layer 370, and may electrically insulate the first counter electrode layer 360 from the second counter electrode layer 370. The insulating layer 380 may include an electrically insulating material that has adhesiveness and is compressible and restorable. For example, the insulating layer 380 may include at least one of an epoxy-based polymer, an acrylic-based polymer, and a silicon-based polymer, but is not limited thereto.

[0204] In another exemplary embodiment, in the flexible vibration module 300, the insulating layer 380 and the second counter electrode layer 370 may be omitted. Fig.11 As illustrated in FIG. 1 , the first counter electrode layer 360 may be electrically connected to the second surface (or front surface) of each of the lower piezoelectric portions 311a in the lower piezoelectric composite layer 310a, and may be electrically connected to the first surface (or rear surface) of each of the upper piezoelectric portions 311b in the upper piezoelectric composite layer 310b. Therefore, the first counter electrode layer 360 may be used as a common electrode (or shared electrode) of the lower piezoelectric composite layer 310a and the upper piezoelectric composite layer 310b, and in each of the plurality of piezoelectric portions 311, the polarization direction of each of the lower piezoelectric portions 311a may be opposite to the polarization direction of each of the upper piezoelectric portions 311b.

[0205] In the flexible vibration module 300 according to the fifth embodiment, the arrangement structure of the piezoelectric portion 311 is not limited to Fig. 9 , and may be changed into various structures based on the required conditions of at least one of the vibration characteristics, flexibility, and size of the flexible vibration module 300. For example, the thickness gradient or vibration frequency of each of the lower piezoelectric portions 311a in each of the piezoelectric portions 311 may not be adjusted to gradually decrease in the direction from the end portions EP1 and EP2 of the piezoelectric composite layer 310 to the first central portion CP1 and may be adjusted to randomly change, or may be adjusted to gradually decrease or randomly change in the direction from one end portion EP1 to the other end portion EP2 of the piezoelectric composite layer 310.

[0206] In the flexible vibration module 300 according to the fifth embodiment of the present disclosure, the plurality of piezoelectric parts 311 may have various vibration frequencies based on the thickness gradient of each of the lower piezoelectric part 311a and the upper piezoelectric part 311b each having a vertical stacking structure. Therefore, the plurality of piezoelectric parts 311 may vibrate the display panel 100 using vibrations having various vibration frequencies by an electric field based on a signal applied to each of the plurality of piezoelectric parts 311. Therefore, the sound pressure flattening (or flatness) characteristics and the sound pressure characteristics of the sound generated based on the vibration of the display panel 100 may be increased, and the sound reproduction band may be expanded. The piezoelectric composite layer 310 may have a bimorph structure, and therefore, the flexible vibration module 300 according to the fifth embodiment of the present disclosure may further increase the expansion force (or tension) and the contraction force (or compression) to fully vibrate the display panel 100 in the vertical direction (or front-to-back direction). Therefore, the sound pressure flattening (or flatness) characteristics and the sound pressure characteristics of the sound generated based on the vibration of the display panel 100 may be increased, and the sound reproduction band may be expanded.

[0207] The flexible vibration module 300 according to the first to fifth embodiments of the present disclosure may have a relatively high flexibility thin film type, and therefore, may be applied to a display device using a display panel as a vibration plate. For example, the flexible vibration module 300 according to the embodiment of the present disclosure may be applied to a flexible display device, and for example, may be applied to a curved display device bent at a specific radius of curvature, but is not limited thereto, and may be applied to a rollable display device wound in a spiral form, a bendable display device, a wearable display device wound around a wrist, or a commercial display device having a plurality of curved portions. For example, the flexible vibration module 300 may be bent based on a specific radius of curvature or may be bent based on spiral winding or non-winding, and may be located in the display panel to correspond to the entire display area of ​​the display panel or overlap with the entire display area of ​​the display panel, or may be located in the display panel to maintain a predetermined distance from the display panel.

[0208] Fig.12 It is along Figure 1 Another cross-sectional view taken along line II' in FIG. Fig.13 Illustrated Fig.12 The flexible vibration module and the separator are respectively illustrated in FIG. Fig.12 and 13 Illustrated by modifying Figure 1 and Figure 2 The embodiment is implemented by the flexible vibration module in the display device illustrated in FIG.

[0209] like Fig.12 and Fig.13As illustrated, in the display device according to another embodiment of the present disclosure, the flexible vibration module 300 may include a first flexible vibration module 300 - 1 and a second flexible vibration module 300 - 2 each on the rear surface of the display panel 100 .

[0210] The rear surface (or back surface) of the display panel 100 may include a first area A1 and a second area A2. For example, the rear surface (or back surface) of the display panel 100 may be divided into the first area A1 and the second area A2. For example, in the rear surface of the display panel 100, the first area A1 may be a left area, and the second area A2 may be a right area. The first area A1 and the second area A2 may be laterally symmetrical with respect to the center line CL of the display panel 100 in the first direction X.

[0211] The first flexible vibration module 300-1 may be in the first area A1 of the display panel 100. The first flexible vibration module 300-1 may vibrate the first area A1 of the display panel 100 to generate a first panel vibration sound PVS1 or a first tactile feedback in the first area A1 of the display panel 100. For example, the first panel vibration sound PVS1 may be a left sound. The first flexible vibration module 300-1 may be configured according to Figures 3 to 11 One of the flexible vibration modules 300 of the first to fifth embodiments of the present disclosure is illustrated in FIG.

[0212] The first flexible vibration module 300-1 may be close to the center portion or edge or periphery of the first area A1 of the display panel 100 in the first direction X. The size of the first flexible vibration module 300-1 may be equal to or greater than half of the first area A, but is not limited thereto, and may be adjusted based on the sound characteristics required by the display device. For example, in the first area A1 of the display panel 100, as the size of the first flexible vibration module 300-1 increases, the vibration area (or vibration zone) of the first area A1 may increase, thereby enhancing the low-pitched vocal cord characteristics of the left sound. On the other hand, in the first area A1 of the display panel 100, as the size of the first flexible vibration module 300-1 decreases, the vibration area (or vibration zone) of the first area A1 may decrease, thereby enhancing the high-pitched vocal cord characteristics of the left sound. Therefore, the size of the first flexible vibration module 300-1 may be adjusted based on the desired vocal cord characteristics according to the vibration of the display panel 100.

[0213] The second flexible vibration module 300-2 may be in the second area A2 of the display panel 100. The second flexible vibration module 300-2 may vibrate the second area A2 of the display panel 100 to generate a second panel vibration sound or a second tactile feedback in the second area A2 of the display panel 100. For example, the second panel vibration sound may be a right sound. The second flexible vibration module 300-2 may be the same as the first flexible vibration module 300-1, and may be symmetrical with the first flexible vibration module 300-1 with respect to the center line CL of the display panel 100. The second flexible vibration module 300-2 according to an embodiment may be close to the central portion or edge or periphery of the second area A2 of the display panel 100 in the first direction X, and may be symmetrical with the first flexible vibration module 300-1 with respect to the center line CL of the display panel 100.

[0214] A display device according to another exemplary embodiment of the present disclosure may output left and right sounds to a front region FD in front of the display panel 100 through a first flexible vibration module 300-1 and a second flexible vibration module 300-2 to provide stereo sound to a user. A display device according to another exemplary embodiment of the present disclosure may further include a partition 700 for separating a vibration region based on the first flexible vibration module 300-1 from a vibration region based on the second flexible vibration module 300-2. The partition 700 according to the embodiment may include a first partition member 710 between the first flexible vibration module 300-1 and the second flexible vibration module 300-2.

[0215] The first partition member 710 may be on the rear center line CL of the display panel 100, and may separate the first panel vibration (or panel vibration sound) generated by the first flexible vibration module 300-1 from the second panel vibration (or panel vibration sound) generated by the second flexible vibration module 300-2. The first partition member 710 according to the embodiment may be between the rear center of the display panel 100 and the rear structure 500, and may spatially separate the gap space GS between the display panel 100 and the rear structure 500. For example, the first partition member 710 may prevent the vibration generated by the first flexible vibration module 300-1 in the first area A1 of the display panel 100 from being transmitted to the second area A2 of the display panel 100, or may prevent the vibration generated by the second flexible vibration module 300-2 in the second area A2 of the display panel 100 from being transmitted to the first area A1 of the display panel 100. Therefore, the first partition member 710 can attenuate or absorb vibration of the display panel 100 at the center of the display panel 100, and thus can block or prevent the sound of the first area A1 from being transmitted to the second area A2 or can block or prevent the sound of the second area A2 from being transmitted to the first area A1. The first partition member 710 may be referred to as a central partition, a sound separation member, a center cover, a center baffle, or a partition, but the term is not limited thereto.

[0216] For example, the first partition member 710 may be formed of one of polyurethane, polyolefin and / or the like, but is not limited thereto. In another example embodiment, the first partition member 710 may be formed of a double-sided tape or a single-sided tape, and, for example, may be formed of a material having an elastic force capable of being compressed to a certain extent. Therefore, the first partition member 710 may separate the left sound from the right sound to further enhance the sound output characteristics of the display device, and the display device including the first partition member 710 may separate the left sound from the right sound by using the first partition member 710 to output a two-channel stereo sound to a front area in front of the display panel 100.

[0217] The partition 700 according to the embodiment may further include a second partition member 720 surrounding the area between the display panel 100 and the rear structure 500. The second partition member 720 may be disposed along a space between the rear edge or rear periphery of the display panel 100 and the front edge or front periphery of the rear structure 500 to surround the entirety of the first flexible vibration module 300-1 and the second flexible vibration module 300-2. The second partition member 720 may be referred to as an edge partition, a sound blocking member, an edge cover, or a baffle, but the term is not limited thereto.

[0218] The second partition member 720 may provide a first air gap AG1 and a second air gap AG2 between the display panel 100 and the rear structure 500 together with the first partition member 710. For example, each of the first air gap AG1 and the second air gap AG2 may be referred to as a vibration space, a sound pressure space, a sound box, a sound portion, a resonance box, or a resonance portion, but the term is not limited thereto. The first air gap AG1 may be in the first area A1 of the display panel 100, surrounded by the first partition member 710 and the second partition member 720 in the first area A1 of the display panel 100. The second air gap AG2 may be in the second area A2 of the display panel 100, surrounded by the first partition member 710 and the second partition member 720 in the second area A2 of the display panel 100.

[0219] The first flexible vibration module 300-1 may be surrounded by portions of the first and second separation members 710 and 720 providing the first air gap AG1, and the second flexible vibration module 300-2 may be surrounded by other portions of the first and second separation members 710 and 720 providing the second air gap AG2. In another example embodiment, the second separation member 720 may be omitted.

[0220] The second partition member 720 may be between the display panel 100 and the rear structure 500, and may surround each of the first flexible vibration module 300-1 and the second flexible vibration module 300-2 individually (or independently) together with the first partition member 710 to ensure a vibration space for each of the first flexible vibration module 300-1 and the second flexible vibration module 300-2. This may enhance the sound pressure characteristics of the left and right sounds, and may prevent the sound or sound pressure from leaking to the outside through the side surface between the display panel 100 and the rear structure 500, thereby enhancing the sound output characteristics of the display device.

[0221] The partition 700 according to the embodiment may further include a third partition member 730 surrounding the first flexible vibration module 300-1 and a fourth partition member 740 surrounding the second flexible vibration module 300-2. The third partition member 730 may be between the display panel 100 and the rear structure 500 to overlap with or correspond to the first air gap AG1, and may surround the first flexible vibration module 300-1 alone (or independently). The third partition member 730 according to the embodiment may have a circular shape surrounding the first flexible vibration module 300-1, but is not limited thereto, and may have a shape that is the same as or different from the overall shape of the first flexible vibration module 300-1. For example, when the first flexible vibration module 300-1 has a rectangular shape, the third partition member 730 may have a rectangular shape having a size relatively larger than that of the first flexible vibration module 300-1.

[0222] The third partition member 730 may limit (or define) the vibration region (or vibration zone) of the display panel 100 based on the first flexible vibration module 300-1. For example, in the first area A1 of the display panel 100, as the size of the third partition member 730 increases, the vibration region of the first area A1 may increase, and thus, the low-pitched vocal cord characteristics of the left sound may be enhanced. On the other hand, in the first area A1 of the display panel 100, as the size of the third partition member 730 decreases, the vibration region of the first area A1 may decrease, and thus, the high-pitched vocal cord characteristics of the left sound may be enhanced. Therefore, the size of the third partition member 730 may be adjusted based on the desired vocal cord characteristics according to the vibration of the display panel 100.

[0223] The fourth partition member 740 may be between the display panel 100 and the rear structure 500 to overlap or correspond to the second air gap AG2, and may surround the second flexible vibration module 300-2 alone (or independently). In order to make the left sound symmetrical with the right sound, the fourth partition member 740 may have the same shape as that of the third partition member 730, and have a structure symmetrical to the third partition member with respect to the rear center line CL of the display panel 100.

[0224] The fourth partition member 740 may limit (or define) the vibration area (or vibration zone) of the display panel 100 based on the second flexible vibration module 300-2. For example, in the second area A2 of the display panel 100, as the size of the fourth partition member 740 increases, the vibration area of ​​the second area A2 may increase, and thus, the low-pitched vocal cord characteristics of the right sound may be enhanced. On the other hand, in the second area A2 of the display panel 100, as the size of the fourth partition member 740 decreases, the vibration area of ​​the second area A2 may decrease, and thus, the high-pitched vocal cord characteristics of the right sound may be enhanced. Therefore, the size of the fourth partition member 740 may be adjusted based on the desired vocal cord characteristics according to the vibration of the display panel 100.

[0225] The third partition member 730 and the fourth partition member 740 may limit the vibration area (or vibration zone) of each of the first flexible vibration module 300-1 and the second flexible vibration module 300-2. This may enhance the lateral symmetry of the left and right sounds generated based on the vibration of the display panel 100, and may optimize the sound pressure characteristics and the sound reproduction band of each of the left and right sounds.

[0226] In some example embodiments, one or more of the first partition member 710, the second partition member 720, the third partition member 730, and the fourth partition member 740 may be formed of double-sided tape or single-sided tape, and, for example, may be formed of a material having an elastic force capable of being compressed to a certain extent.

[0227] Fig.14 Examples of each Fig.12 The flexible vibration module and the separator illustrated in the example, and the example by modifying Fig.13 An embodiment realized by using the first partition member illustrated in FIG.

[0228] like Fig.14 As illustrated, in a display device according to another embodiment of the present disclosure, the first partitioning member 710 may include a first sub-partitioning member 711 and a second sub-partitioning member 713 spaced apart from each other on a rear center line CL of the display panel 100. The first partitioning member 710 including the first sub-partitioning member 711 and the second sub-partitioning member 713 may be referred to as at least one first partitioning member.

[0229] The first sub-partitioning member 711 and the second sub-partitioning member 713 may be between the rear center of the display panel 100 and the rear structure 500. For example, the first sub-partitioning member 711 and the second sub-partitioning member 713 may be located side by side between the rear center of the display panel 100 and the rear structure 500. The first sub-partitioning member 711 and the second sub-partitioning member 713 may provide or form first to third air gaps AG1 to AG3 between the display panel 100 and the rear structure 500 together with the second partitioning member 720.

[0230] The first air gap AG1 may be in the first area A1 of the display panel 100, surrounded by the first sub-partitioning member 711 and the second partitioning member 720 in the first area A1 of the display panel 100. The second air gap AG2 may be in the second area A2 of the display panel 100, surrounded by the second sub-partitioning member 713 and the second partitioning member 720 in the second area A2 of the display panel 100.

[0231] The third air gap AG3 may be surrounded by the first sub-partitioning member 711 and the second sub-partitioning member 713 and the second partitioning member 720 in the central area of ​​the display panel 100. For example, the third air gap AG3 may be provided in an area between the first air gap AG1 and the second air gap AG2 including the rear center line CL of the display panel 100. The third air gap AG3 may be referred to as a sound separation space, a sound blocking space, or a sound interference prevention space, but the term is not limited thereto. The third air gap AG3 may spatially separate the first air gap AG1 from the second air gap AG2, and thus, a resonance phenomenon or an interference phenomenon in a certain frequency band occurring in each of the first air gap AG1 and the second air gap AG2 may be prevented. In another example embodiment, the second partitioning member 720 may be omitted.

[0232] The first flexible vibration module 300-1 may be surrounded by the first sub-partitioning member 711 and the second partitioning member 720 providing the first air gap AG1. The second flexible vibration module 300-2 may be surrounded by the other parts of the second sub-partitioning member 713 and the second partitioning member 720 providing the second air gap AG2. The first partitioning member 710 including the first sub-partitioning member 711 and the second sub-partitioning member 713 together with the second partitioning member 720 may provide a first air gap AG1, a second air gap AG2, and a third air gap AG3 between the first air gap AG1 and the second air gap AG2 that may independently surround each of the first flexible vibration module 300-1 and the second flexible vibration module 300-2. This may ensure a vibration space for each of the first flexible vibration module 300-1 and the second flexible vibration module 300-2 to increase the sound pressure characteristics of the left and right sounds and prevent the resonance phenomenon or interference phenomenon of the left and right sounds, thereby further enhancing the sound pressure characteristics of the left and right sounds. Therefore, the sound output characteristics of the display device may be further enhanced.

[0233] FIG. 15A to FIG. 15C Illustrated Fig.14 The first flexible vibration module and the second flexible vibration module in the embodiment of the present invention are modified, and the modified embodiment of the present invention is illustrated. Fig.14 The embodiment is achieved by arranging the piezoelectric part in the piezoelectric composite layer.

[0234] like Fig.15A As illustrated, in each of the first flexible vibration module 300-1 and the second flexible vibration module 300-2 according to the first modified exemplary embodiment, except that the length of each of the plurality of piezoelectric portions 311 gradually increases in a direction from the edge or periphery of the display panel 100 to the center line CL based on a length gradient, each of the first flexible vibration module 300-1 and the second flexible vibration module 300-2 is similar to Figure 3 or Fig.13 Therefore, the plurality of piezoelectric parts 311 according to the first modified embodiment may each have a different vibration frequency based on a different length. Therefore, the sound pressure characteristics of each of the left sound and the right sound generated based on the vibration of the display panel 100 may be increased and the sound reproduction band may be expanded. Fig.15A In the embodiment of the present invention, the second partition member 720 may be omitted.

[0235] like Fig. 15BAs illustrated, in each of the first flexible vibration module 300-1 and the second flexible vibration module 300-2 according to the second modified embodiment, except that the length of each of the plurality of piezoelectric portions 311 gradually increases in a direction from the edge or periphery of the display panel 100 to the center line CL based on a length gradient, each of the first flexible vibration module 300-1 and the second flexible vibration module 300-2 is similar to Figure 6 The same as the flexible vibration module illustrated in . Therefore, the plurality of piezoelectric parts 311 according to the second modified embodiment can each have a different vibration frequency based on a different length. Therefore, the sound pressure characteristics of each of the left sound and the right sound generated based on the vibration of the display panel 100 can be increased and the sound reproduction band can be expanded. Fig. 15B In the embodiment of the present invention, the second partition member 720 may be omitted.

[0236] like Fig. 15C As illustrated, in each of the first flexible vibration module 300-1 and the second flexible vibration module 300-2 according to the third modified embodiment, except that the width of each of the plurality of piezoelectric portions 311 gradually increases in a direction from the edge or periphery of the display panel 100 to the center line CL based on a width gradient, each of the first flexible vibration module 300-1 and the second flexible vibration module 300-2 is similar to Figure 7 Therefore, the plurality of piezoelectric parts 311 according to the third modified embodiment may each have a different vibration frequency based on a different width. Therefore, the sound pressure characteristics of each of the left sound and the right sound generated based on the vibration of the display panel 100 may be increased and the sound reproduction band may be expanded. Fig. 15C In the embodiment of the present invention, the second partition member 720 may be omitted.

[0237] Figures 16A to 16C Various display devices to which the flexible vibration module according to the embodiments of the present disclosure can be applied are illustrated, and the application Figures 3 to 11 Each of the flexible vibration modules illustrated in the display device.

[0238] The flexible vibration module according to an embodiment of the present disclosure may be implemented as a film type having flexibility, and thus, may be applied to various application devices.

[0239] like Fig.16AAs illustrated, the flexible vibration module 300 according to the embodiment of the present disclosure may be applied to a commercial display device or a flexible display device including a display panel 100, wherein the display panel 100 includes a plurality of concave or convex curved surface portions CSP. For example, the flexible vibration module 300 may be bent into a shape having a curvature value (or a curvature radius) that matches or corresponds to a concave portion or a convex portion of each of the curved surface portions CSP of the display panel 100, and may be located in the concave portion or the convex portion of each of the curved surface portions CSP of the display panel 100. In another example embodiment, the flexible vibration module 300 may have a shape that matches a curvature value (or a curvature radius) of each of the curved surface portions CSP of the display panel 100, and may be on the entire rear surface of the display panel 100.

[0240] like Fig. 16B As illustrated, the flexible vibration module 300 according to an embodiment of the present disclosure may be applied to a rollable display device including a display panel 100 that is not rolled or is rolled in a spiral shape. For example, the flexible vibration module 300 according to an embodiment of the present disclosure may have a shape having a curvature value (or a curvature radius) of a display panel 100 that is not rolled or is rolled in a spiral shape. A plurality of flexible vibration modules 300 may be arranged on the rear surface of the display panel 100 at a certain interval or distance. In another example embodiment, the flexible vibration module 300 may have a shape that matches or corresponds to the curvature value (or curvature radius) of the display panel 100, and may be on the entire rear surface of the display panel 100.

[0241] like Fig. 16C As illustrated, the flexible vibration module 300 according to an embodiment of the present disclosure may be applied to a wearable display device including a display panel 100 that is wrapped around a user's wrist and bent into a C-shape. For example, the flexible vibration module 300 according to an embodiment of the present disclosure may have a shape having a curvature value (or a curvature radius) of the display panel 100 bent into a C-shape. A plurality of flexible vibration modules 300 may be arranged on the rear surface of the display panel 100 at a certain interval or distance. In another example embodiment, the flexible vibration module 300 may have a shape that matches the curvature value (or curvature radius) of the display panel 100 bent into a C-shape, and may be provided on the entire rear surface of the display panel 100.

[0242] Fig.17 is a graph showing the sound pressure characteristics of a display panel according to an embodiment of the present disclosure and the sound pressure characteristics of a display panel according to a comparative example. Fig.17In the sound pressure measurement, Audio Precision's APx525 was used, sine sweep was applied at 20Hz to 20kHz, and the sound pressure was measured at a position 50cm away from the display panel, flexible vibration module, and membrane speaker. Sine sweep may be a process of performing a scan in a short time, but the process is not limited to this. Fig.17 , the x-axis represents the frequency in Hertz (Hz), and the y-axis represents the sound pressure level in decibel (dB).

[0243] In an exemplary embodiment of the present disclosure (thick solid line), a Fig.15A In the display device illustrated in FIG. 1 , there is no display panel with a partition. In a comparative example (dashed line), a display panel in which a flexible vibration module including a plurality of piezoelectric portions having the same length without a length gradient is attached to each of the left and right regions is prepared.

[0244] like Fig.17 As illustrated in FIG. 1 , the display panel according to the embodiment of the present disclosure (thick solid line) has a sound pressure level of 50 dB or more in the entire audible frequency and a sound pressure level that is about 10 dB higher in the high-pitched vocal band and the low-pitched vocal band, and the drop in the sound pressure level in the entire audible frequency is reduced, thereby improving the flatness of the sound pressure level. Here, the sound flatness characteristic may be the size of the deviation between the highest sound pressure level and the lowest sound pressure level.

[0245] Therefore, in the flexible vibration module and the display device including the flexible vibration module according to the present disclosure, the plurality of piezoelectric parts constituting the piezoelectric composite layer have various vibration frequencies based on the size gradient, thereby increasing the sound pressure characteristics in the entire audible frequency and expanding the sound reproduction band.

[0246] The flexible vibration module according to the present disclosure and the display device including the flexible vibration module can be applied to various applications. For example, a display panel provided with the flexible vibration module according to the present disclosure and a display device including the display panel can be applied to a mobile device, a video phone, a smart watch, a watch phone, a wearable device, a foldable device, a rollable device, a bendable device, a flexible device, a bending device, an electronic notebook, an electronic book, a portable multimedia player (PMP), a personal digital assistant (PDA), an MP3 player, a mobile medical device, an electronic notepad, a desktop personal computer (PC), a portable PC, a netbook computer, a workstation, a navigation device, a car navigation device, a car display device, a television (TV), a wallpaper display device, a sign device, a game console, a notebook computer, a monitor, a camera, a portable camera, a home appliance, etc.

[0247] The flexible vibration module according to the embodiment of the present disclosure may be applied to an organic light emitting lighting device or an inorganic light emitting lighting device. In the case where the flexible vibration module according to the present disclosure is applied to a lighting device, the flexible vibration module may function as a lighting device and a speaker. In some example embodiments, the flexible vibration module according to the present disclosure may be applied to a mobile device, and the flexible vibration module may function as a speaker or a receiver, but is not limited thereto.

[0248] Hereinafter, a flexible vibration module and a display device including the same according to the present disclosure will be described.

[0249] According to some example embodiments of the present disclosure, a flexible vibration module includes a piezoelectric composite layer including: a plurality of piezoelectric portions each having a piezoelectric property, wherein at least two of the plurality of piezoelectric portions have different sizes; and a flexible portion between the plurality of piezoelectric portions.

[0250] According to some example embodiments of the present disclosure, each of the plurality of piezoelectric portions may have a different size and a different vibration frequency.

[0251] According to some example embodiments of the present disclosure, at least two of the plurality of piezoelectric portions may have a length, a width, and a thickness, and some or at least one of the plurality of piezoelectric portions may have different lengths, different widths, and different thicknesses.

[0252] According to some example embodiments of the present disclosure, one of the length, width, and thickness of each of the plurality of piezoelectric portions may gradually increase or decrease in a direction from at least one end portion of the piezoelectric composite layer to a central portion of the piezoelectric composite layer.

[0253] According to some example embodiments of the present disclosure, one of the length, width, and thickness of each of the plurality of piezoelectric portions may be randomly changed between one end and the other end of the piezoelectric composite layer.

[0254] According to some example embodiments of the present disclosure, one of the length, width, and thickness of each of the plurality of piezoelectric portions may gradually increase or decrease in a direction from one end of the piezoelectric composite layer to another end opposite to the end.

[0255] According to some example embodiments of the present disclosure, each of the plurality of piezoelectric portions may include: a lower piezoelectric portion; and an upper piezoelectric portion, the upper piezoelectric portion being on the lower piezoelectric portion. Each of the plurality of piezoelectric portions may have the same thickness.

[0256] According to some example embodiments of the present disclosure, at least two of the lower piezoelectric portions may have different thicknesses.

[0257] According to some example embodiments of the present disclosure, a plurality of piezoelectric portions may have the same thickness, and the thickness of each of the lower piezoelectric portions may change stepwise or randomly in a direction from one end of the piezoelectric composite layer to another end opposite to the end.

[0258] According to some example embodiments of the present disclosure, the flexible vibration module may further include an electrode between the lower piezoelectric portion and the upper piezoelectric portion.

[0259] According to some example embodiments of the present disclosure, the flexible vibration module may further include a first electrode between the lower piezoelectric portion and the upper piezoelectric portion; a second electrode between the lower piezoelectric portion and the upper piezoelectric portion; and an insulating layer between the first electrode and the second electrode.

[0260] According to some example embodiments of the present disclosure, a flexible vibration module may include a piezoelectric composite layer including a plurality of piezoelectric portions having piezoelectric characteristics and a flexible portion disposed between the plurality of piezoelectric portions, wherein the piezoelectric composite layer may have a plurality of vibration frequencies.

[0261] According to some example embodiments of the present disclosure, at least two of the plurality of piezoelectric portions may have different vibration frequencies.

[0262] According to some example embodiments of the present disclosure, a vibration frequency of each of the plurality of piezoelectric portions may be changed stepwise or randomly in a direction from one end portion of the piezoelectric composite layer to another end portion opposite to the end portion.

[0263] According to some example embodiments of the present disclosure, each of the plurality of piezoelectric portions may include: a lower piezoelectric portion; and an upper piezoelectric portion, the upper piezoelectric portion being on the lower piezoelectric portion.

[0264] According to some example embodiments of the present disclosure, a plurality of piezoelectric portions may have the same thickness, and the thickness of each of the lower piezoelectric portions may gradually become thicker or thinner in a direction from at least one end of the piezoelectric composite layer to a central portion of the piezoelectric composite layer.

[0265] According to some example embodiments of the present disclosure, each of the plurality of piezoelectric portions may include an inorganic material, and the flexible portion may include at least one of an organic piezoelectric material and an organic non-piezoelectric material.

[0266] According to some example embodiments of the present disclosure, a display device may include: a flexible vibration module including: a piezoelectric composite layer including: a plurality of piezoelectric portions each having a piezoelectric property, wherein at least two of the plurality of piezoelectric portions may have different sizes; and a flexible portion between the plurality of piezoelectric portions; and a display panel, wherein the display panel may include a display area configured to display an image and vibrate according to vibration of the flexible vibration module. The display device may also include a touch electrode configured to sense a touch, wherein the flexible vibration module may be configured to vibrate according to the touch. Each of the plurality of piezoelectric portions may include an inorganic material, and the flexible portion may include at least one of an organic piezoelectric material and an organic non-piezoelectric material.

[0267] According to some example embodiments of the present disclosure, the display panel may include a first region and a second region, the flexible vibration module may be a first flexible vibration module in the first region of the display panel; and the second flexible vibration module may be in the second region of the display panel.

[0268] According to some example embodiments of the present disclosure, the display device may further include: a rear structure on a rear surface of the display panel; and at least one partition between the display panel and the rear structure, and between the first flexible vibration module and the second flexible vibration module.

[0269] According to some example embodiments of the present disclosure, the display device may further include: a rear structure on a rear surface of the display panel; and a partition between the display panel and the rear structure, wherein the partition may surround at least one of the first flexible vibration module and the second flexible vibration module.

[0270] According to some example embodiments of the present disclosure, the display device may further include another spacer between the display panel and the rear structure, and the another spacer may surround both the first flexible vibration module and the second flexible vibration module and the spacer.

[0271] The above-mentioned features, structures and effects of the present disclosure are included in at least one embodiment of the present disclosure, but are not limited to only one embodiment. In addition, the features, structures and effects described in at least one embodiment of the present disclosure can be realized by combining or modifying other embodiments by those skilled in the art. Therefore, the contents associated with the combination and modification should be interpreted as falling within the scope of the present disclosure.

[0272] It should be clear to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is intended to cover the modified and modified forms of the present disclosure, provided that they fall within the scope of the attached claims and their equivalents.

[0273] CROSS-REFERENCE TO RELATED APPLICATIONS

[0274] This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0037507, filed on Mar. 29, 2019, which is hereby incorporated by reference in its entirety for all purposes as if fully set forth herein.

Claims

1. A flexible vibration module for outputting sound, the flexible vibration module comprising: A piezoelectric composite layer, comprising: a plurality of piezoelectric portions each having a piezoelectric characteristic, wherein at least two of the plurality of piezoelectric portions have different sizes; and a flexible portion between the plurality of piezoelectric portions, wherein the plurality of piezoelectric portions have a horizontally symmetrical structure relative to a first central portion of the piezoelectric composite layer in a first direction, wherein the at least two piezoelectric portions among the plurality of piezoelectric portions have different lengths in a second direction perpendicular to the first direction, Wherein, the first direction is parallel to the width direction of the piezoelectric composite layer, and Wherein, the second direction is parallel to the length direction of the piezoelectric composite layer.

2. The flexible vibration module according to claim 1, wherein: Any two piezoelectric portions among the plurality of piezoelectric portions located in a region between the first central portion and one end portion of the piezoelectric composite layer have different sizes and different vibration frequencies.

3. The flexible vibration module according to claim 1, wherein: At least two of the plurality of piezoelectric portions have different vibration frequencies.

4. The flexible vibration module according to claim 1, wherein: A size of each of the plurality of piezoelectric portions gradually increases or decreases in a direction from at least one end portion of the piezoelectric composite layer to the first central portion of the piezoelectric composite layer.

5. The flexible vibration module according to claim 1, wherein: A length of each of the plurality of piezoelectric portions gradually increases or decreases in a direction from one end portion of the piezoelectric composite layer to the first center portion of the piezoelectric composite layer.

6. The flexible vibration module according to claim 1, wherein: The flexible vibration module also includes: a first electrode located on first surfaces of the plurality of piezoelectric portions and a first surface of the flexible portion; and a second electrode located on a second surface of the plurality of piezoelectric portions and a second surface of the flexible portion, Wherein, each of the first surfaces of the plurality of piezoelectric portions and the first surface of the flexible portion and the second surfaces of the plurality of piezoelectric portions and the second surface of the flexible portion is configured to have a planar structure.

7. The flexible vibration module according to claim 6, wherein: The plurality of piezoelectric portions all have the same thickness.

8. The flexible vibration module according to claim 1, wherein: The flexible portion comprises: a plurality of flexible patterns between the plurality of piezoelectric portions; and A flexible dummy pattern is provided in a dummy region of the piezoelectric composite layer where the plurality of flexible patterns and the plurality of piezoelectric portions are not provided.

9. The flexible vibration module according to claim 8, wherein: A size of the flexible dummy pattern changes stepwise in a direction from one end portion of the piezoelectric composite layer to a central portion of the piezoelectric composite layer.

10. A flexible vibration module for outputting sound, the flexible vibration module comprising: A piezoelectric composite layer, comprising: a plurality of piezoelectric portions each having a piezoelectric characteristic; and a flexible portion between the plurality of piezoelectric portions, Wherein, the piezoelectric composite layer has multiple vibration frequencies. wherein the plurality of piezoelectric portions have a horizontally symmetrical structure relative to a first central portion of the piezoelectric composite layer in a first direction, wherein at least two of the plurality of piezoelectric portions have different lengths in a second direction perpendicular to the first direction, Wherein, the first direction is parallel to the width direction of the piezoelectric composite layer, and Wherein, the second direction is parallel to the length direction of the piezoelectric composite layer.

11. The flexible vibration module according to claim 10, wherein: At least two of the plurality of piezoelectric portions have different vibration frequencies.

12. The flexible vibration module according to claim 10, wherein: The flexible portion comprises: a plurality of flexible patterns between the plurality of piezoelectric portions; and A flexible dummy pattern is provided in a dummy region of the piezoelectric composite layer where the plurality of flexible patterns and the plurality of piezoelectric portions are not provided.

13. The flexible vibration module according to claim 12, wherein: A size of the flexible dummy pattern changes stepwise in a direction from one end portion of the piezoelectric composite layer to the first center portion of the piezoelectric composite layer.

14. The flexible vibration module according to any one of claims 1 to 13, wherein: The plurality of piezoelectric portions have a vertically asymmetric structure with respect to a second central portion of the piezoelectric composite layer in the second direction.

15. The flexible vibration module according to any one of claims 1 to 13, wherein: The plurality of piezoelectric portions have a vertically symmetrical structure with respect to a second central portion of the piezoelectric composite layer in the second direction.

16. The flexible vibration module according to any one of claims 1 to 13, wherein: Each of the plurality of piezoelectric portions has the same width in the first direction.

17. The flexible vibration module according to any one of claims 1 to 13, wherein: Each of the plurality of piezoelectric portions comprises an inorganic material, and The flexible portion includes at least one of an organic piezoelectric material and an organic non-piezoelectric material.

18. A display device, comprising: A flexible vibration module for outputting sound, the flexible vibration module comprising: A piezoelectric composite layer, comprising: a plurality of piezoelectric portions each having a piezoelectric characteristic, wherein at least two of the plurality of piezoelectric portions have different sizes; and a flexible portion between the plurality of piezoelectric portions; and a display panel, wherein the display panel includes a display area configured to display an image and vibrate according to the vibration of the flexible vibration module, wherein the plurality of piezoelectric portions have a horizontally symmetrical structure relative to a first central portion of the piezoelectric composite layer in a first direction, wherein the at least two piezoelectric portions among the plurality of piezoelectric portions have different lengths in a second direction perpendicular to the first direction, Wherein, the first direction is parallel to the width direction of the piezoelectric composite layer, and Wherein, the second direction is parallel to the length direction of the piezoelectric composite layer.

19. The display device according to claim 18, wherein: A size of each of the plurality of piezoelectric portions gradually increases or decreases in a direction from at least one end portion of the piezoelectric composite layer to the first central portion of the piezoelectric composite layer.

20. The display device according to claim 18, further comprising a touch electrode configured to sense a touch, wherein The flexible vibration module is configured to vibrate according to the touch.

21. The display device according to claim 19, wherein: Each of the plurality of piezoelectric portions comprises an inorganic material; and The flexible portion includes at least one of an organic piezoelectric material and an organic non-piezoelectric material.

22. The display device according to claim 19, wherein: The display panel includes a first area and a second area; The flexible vibration module is a first flexible vibration module in the first area of ​​the display panel; and A second flexible vibration module is in the second area of ​​the display panel.

23. The display device according to claim 22, further comprising: a rear structure on a rear surface of the display panel; as well as At least one partition member is between the display panel and the rear structure and between the first flexible vibration module and the second flexible vibration module.

24. The display device according to claim 22, further comprising: a rear structure on a rear surface of the display panel; as well as a spacer between the display panel and the rear structure, The partition surrounds at least one of the first flexible vibration module and the second flexible vibration module. 25 . The display device of claim 24 , further comprising another partition between the display panel and the rear structure, the other partition surrounding both the first flexible vibration module and the second flexible vibration module and the partition.

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