Patent Publication Number: US-11647336-B2

Title: Display apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. patent application Ser. No. 16/711,988, filed on Dec. 12, 2019, which claims the benefit and priority to Korean Patent Application No. 10-2018-0166356 filed on Dec. 20, 2018, the entirety of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a display apparatus. 
     Discussion of the Related Art 
     Display apparatuses are equipped in home appliances or electronic apparatuses, such as televisions (TVs), monitors, notebook computers, smartphones, tablet computers, electronic organizers, electronic pads, wearable apparatuses, watch phones, portable information apparatuses, navigation apparatuses, and automotive control display apparatuses, and are used as a screen for displaying an image. Display apparatuses include a display panel for displaying an image and a sound device for outputting a sound associated with the image. 
     Recently, in display apparatuses, there is a trend of enlarging a screen, but the requirements for weight-lightening and slimming are increasing. However, since display apparatuses should include a sufficient space into which a sound device such as a speaker for outputting a sound is embedded, it is difficult to weight-lighten and slim. In a case where a sound device is configured with a piezoelectric member capable of being slimmed, the sound device is easily damaged by an external impact. Also, a sound generated by a sound device embedded into a display apparatus is output in a rearward direction or a sideward direction with respect to a body of the display apparatus, instead of a forward direction with respect to the display panel, and thus, does not travel toward a viewer (or a user) who is watching an image in front of the display apparatus, whereby immersion of the viewer watching the image is hindered. 
     SUMMARY 
     Accordingly, embodiments of the present disclosure are directed to providing a display apparatus that substantially obviates one or more issues due to limitations and disadvantages of the related art. 
     Therefore, the present inventors have recognized the above-described problems and have made various experiments so that when watching an image in front of a display panel, a traveling direction of a sound becomes a direction toward a front surface of the display panel, and durability against an external impact is enhanced. Through the various experiments, the present inventors have implemented a display apparatus having a new structure, which outputs a sound having a traveling direction toward a front surface of a display panel and is enhanced in durability against an external impact. 
     An aspect of the present disclosure is to provide a display apparatus which vibrates a display panel to output a sound to a forward region in front of the display panel and is enhanced in durability against an external impact. 
     Additional features and aspects will be set forth in the description that follows, and in part will be apparent from description or may be learned by practice of inventive concepts provided herein. Other features and aspects of the inventive concepts may be realized and attained by the structure particularly pointed out in the written description, or derivable therefrom, and the claims hereof as well as the appended drawings. 
     To achieve these and other aspects of the inventive concepts, as embodied and broadly described herein, a display apparatus comprises a display module including a display panel configured to display an image and a sound generating module on a rear surface of the display panel, wherein the sound generating module includes a vibration generating device, a circuit board on a lower surface of the vibration generating device, a first adhesive member between the circuit board and the vibration generating device, and a second adhesive member between the vibration generating device and the display panel, an elastic modulus of the second adhesive member differing from an elastic modulus of the first adhesive member. 
     In another aspect, a display apparatus comprises a display module including a display panel configured to display an image and a sound generating module on a rear surface of the display panel, wherein the sound generating module includes a vibration generating device, a circuit board on a lower surface of the vibration generating device, a first adhesive member and a third adhesive member between the circuit board and the vibration generating device, and a member between the first adhesive member and the third adhesive member. 
     Other systems, methods, features and advantages will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the present disclosure, and be protected by the following claims. Nothing in this section should be taken as a limitation on those claims. Further aspects and advantages are discussed below in conjunction with embodiments of the disclosure. It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are examples and explanatory and are intended to provide further explanation of the disclosure as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, that may be included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this disclosure, illustrate embodiments of the disclosure and together with the description serve to explain various principles of the disclosure. 
         FIG.  1    is a perspective view illustrating a display apparatus according to an embodiment of the present disclosure. 
         FIG.  2    is a cross-sectional view taken along line I-I′ illustrated in  FIG.  1   . 
         FIG.  3    illustrates a simulation result of a strain energy density in a sound generating module according to an embodiment of the present disclosure. 
         FIGS.  4 A and  4 B  are diagrams illustrating a sound generating module according to an embodiment of the present disclosure. 
         FIG.  5    is a diagram illustrating a height and a sound pressure level in an impact test process performed on a sound generating module according to an embodiment of the present disclosure. 
         FIG.  6    is a cross-sectional view taken along line I-I′ illustrated in  FIG.  1    according to another embodiment of the present disclosure. 
         FIG.  7    is a cross-sectional view taken along line I-I′ illustrated in  FIG.  1    according to another embodiment of the present disclosure. 
         FIGS.  8 A to  8 C  are detailed views of  FIG.  7    according to another embodiment of the present disclosure. 
         FIG.  9    is a rear view of a display apparatus according to another embodiment of the present disclosure. 
         FIG.  10    is a perspective view illustrating a display apparatus according to another embodiment of the present disclosure. 
         FIG.  11    is a cross-sectional view taken along line II-II′ illustrated in  FIG.  10   . 
         FIG.  12    is a cross-sectional view taken along line II-II′ illustrated in  FIG.  10    according to another embodiment of the present disclosure. 
         FIG.  13    illustrates a rear view of a display panel according to another embodiment of the present disclosure. 
         FIG.  14    illustrates a rear view of a display panel according to another embodiment of the present disclosure. 
         FIGS.  15 A and  15 B  are rear views of a display panel according to another embodiment of the present disclosure. 
         FIGS.  16 A and  16 B  are rear views of a display panel according to another embodiment of the present disclosure. 
         FIG.  17    illustrates a sound output characteristic of a sound generating module according to an embodiment of the present disclosure. 
         FIGS.  18 A and  18 B  illustrate a sound output characteristic of a sound generating module according to an embodiment of the present disclosure. 
         FIGS.  19 A and  19 B  illustrate a sound output characteristic of a sound generating module according to an embodiment of the present disclosure. 
         FIGS.  20 A and  20 B  illustrate a sound output characteristic of a sound generating module according to an embodiment of the present disclosure. 
     
    
    
     Throughout the drawings and the detailed description, unless otherwise described, the same drawing reference numerals should be understood to refer to the same elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustration, and convenience. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. In the following description, when a detailed description of well-known functions or configurations related to this document is determined to unnecessarily cloud a gist of the inventive concept, the detailed description thereof will be omitted. The progression of processing steps and/or operations described is an example; however, the sequence of steps and/or operations is not limited to that set forth herein and may be changed as is known in the art, with the exception of steps and/or operations necessarily occurring in a particular order. Like reference numerals designate like elements throughout. Names of the respective elements used in the following explanations are selected only for convenience of writing the specification and may be thus different from those used in actual products. 
     Advantages and features of the present disclosure, and implementation methods thereof will be clarified through following embodiments described with reference to the accompanying drawings. The present disclosure may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. Further, the present disclosure is only defined by scopes of claims. 
     A shape, a size, a ratio, an angle, and a number disclosed in the drawings for describing embodiments of the present disclosure are merely an example, and thus, the present disclosure is not limited to the illustrated details. In the following description, when the detailed description of the relevant known function or configuration is determined to unnecessarily obscure the important point of the present disclosure, the detailed description of such known function or configuration may be omitted. When terms “comprise,” “have,” and “include” described in the present specification are used, another part may be added unless a more limiting term, such as “only,” is used. The terms of a singular form may include plural forms unless referred to the contrary. 
     In construing an element, the element is construed as including an error or tolerance range even where no explicit description of such an error or tolerance range. 
     In describing a position relationship when a position relation between two parts is described as “on,” “over,” “under,” and “next,” one or more other parts may be disposed between the two parts unless a more limiting term, such as “just” or “direct(ly)” is used. 
     In describing a time relationship, for example, when the temporal order is described as “after,” “subsequent,” “next,” and “before,” a case which is not continuous may be included unless a more limiting term, such as “just” “immediate(ly),” or “direct(ly)” is used. 
     It will be understood that, although the terms “first,” “second,” may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure. 
     In describing the elements of the present disclosure, terms such as “first,” “second,” “A,” “B,” “(a),” “(b), may be used. Such terms are used for merely discriminating the corresponding elements from other elements and the corresponding elements are not limited in their essence, sequence, or precedence by the terms. It will be understood that when an element or layer is referred to as being “on” or “connected to” another element or layer, it can be directly on or directly connected to the other element or layer, or intervening elements or layers may be present. Also, it should be understood that when one element is disposed on or under another element, this may denote a case where the elements are disposed to directly contact each other, but may denote that the elements are disposed without directly contacting each other. 
     The term “at least one” should be understood as including any and all combinations of one or more of the associated listed items. For example, the meaning of “at least one of a first item, a second item, and a third element” denotes the combination of all items proposed from two or more of the first item, the second item, and the third item as well as the first item, the second item, or the third item. 
     In the description of embodiments, when a structure is described as being positioned “on or above” or “under or below” another structure, this description should be construed as including a case in which the structures contact each other as well as a case in which a third structure is disposed therebetween. The size and thickness of each element shown in the drawings are given merely for the convenience of description, and embodiments of the present disclosure are not limited thereto, unless otherwise specified. 
     Features of various embodiments of the present disclosure may be partially or overall coupled to or combined with each other, and may be variously inter-operated with each other and driven technically as those skilled in the art can sufficiently understand. The embodiments of the present disclosure may be carried out independently from each other, or may be carried out together in co-dependent relationship. 
     In the present disclosure, examples of a display apparatus may include a narrow-sense display apparatus such as an organic light emitting display (OLED) module or a liquid crystal module (LCM) including a display panel and a driver for driving the display panel. Also, examples of the display apparatus may include a set device (or a set apparatus) or a set electronic apparatus such as a notebook computer, a TV, a computer monitor, an equipment apparatus including an automotive apparatus or another type apparatuses for vehicles, or a mobile electronic apparatus such as a smartphone or an electronic pad, which is a complete product (or a final product) including an LCM or an OLED module. 
     Therefore, in the present disclosure, examples of the display apparatus may include a narrow-sense display apparatus itself, such as an LCM or an OLED module, and a set apparatus which is a final consumer apparatus or an application product including the LCM or the OLED module. 
     In some embodiments, an LCM or an OLED module including a display panel and a driver may be referred to as a narrow-sense display apparatus, and an electronic apparatus which is a final product including an LCM or an OLED module may be referred to as a set apparatus. For example, the narrow-sense display apparatus may include a display panel, such as an LCD or an OLED, and a source printed circuit board (PCB) which is a controller for driving the display panel. The set apparatus may further include a set PCB which is a set controller electrically connected to the source PCB to overall control the set apparatus. 
     A display panel applied to the present embodiment may use any type of display panel, such as a liquid crystal display panel, an organic light emitting diode (OLED) display panel, and an electroluminescent display panel, but is not limited to a specific display panel which is vibrated by a sound generation device according to an embodiment of the present disclosure to output a sound. Also, a shape or a size of a display panel applied to a display apparatus according to an embodiment of the present disclosure is not limited. 
     For example, if the display panel is the liquid crystal display panel, the display panel may include a plurality of gate lines, a plurality of data lines, and a plurality of pixels respectively in a plurality of pixel areas defined by intersections of the gate lines and the data lines. Also, the display panel may include an array substrate including a thin film transistor (TFT) which is a switching element for adjusting a light transmittance of each of the plurality of pixels, an upper substrate including a color filter and/or a black matrix, and a liquid crystal layer between the array substrate and the upper substrate. 
     Moreover, if the display panel is the organic light emitting display panel, the display panel may include a plurality of gate lines, a plurality of data lines, and a plurality of pixels respectively provided in a plurality of pixel areas defined by intersections of the gate lines and the data lines. Also, the display panel may include an array substrate including a TFT which is an element for selectively applying a voltage to each of the pixels, an organic light emitting device layer on the array substrate, and an encapsulation substrate disposed on the array substrate to cover the organic light emitting device layer. The encapsulation substrate may protect the TFT and the organic light emitting device layer from an external impact and may prevent water or oxygen from penetrating into the organic light emitting device layer. Also, a layer provided on the array substrate may include an inorganic light emitting layer (for example, a nano-sized material layer, a quantum dot, or the like). As another example, the layer provided on the array substrate may include a micro light emitting diode. 
     The display panel may further include a backing such as a metal plate attached on the display panel. However, embodiments are not limited to the metal plate, and the display panel may include another structure. 
     In the present disclosure, the display panel may be applied to vehicles as a user interface module such as a central control panel for automobiles. For example, the display panel may be provided between occupants sitting on two front seats in order for a vibration of the display panel to be transferred to the inside of a vehicle. Therefore, an audio experience in a vehicle is improved in comparison with a case where speakers are disposed on interior sides of the vehicle. 
     Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a perspective view illustrating a display apparatus according to an embodiment of the present disclosure.  FIG.  2    is a cross-sectional view taken along line I-I′ illustrated in  FIG.  1   . 
     With reference to  FIGS.  1  and  2   , the display apparatus  10  according to an embodiment of the present disclosure may include a display module  100 , a supporting member  300 , and a sound generating module  400 . 
     The display module  100  may include a display panel  110 . The display panel  110  may display an image, for example, an electronic image or a digital image, and may be implemented as any type of display panel, such as a liquid crystal display panel, an organic light emitting diode (OLED) display panel, an electroluminescent display panel, etc. The display panel  110  may vibrate based on a vibration of the sound generating module  400  to output sound in a forward direction with respect to the display panel  110 . 
     For example, the display panel  110  may be a light emitting display panel or a flexible light emitting display panel, but is not limited thereto. The display panel  110  may include a pixel array substrate including a pixel array layer including a plurality of pixels and an encapsulation layer that encapsulates the pixel array layer. 
     For example, the display panel  110  may display an image in a type such as a top emission type, a bottom emission type, or a dual emission type, based on a structure of a pixel array layer including an anode electrode, a cathode electrode, and an organic compound layer. In the top emission type, visible light emitted from the pixel array layer may be irradiated onto a region in front of a base substrate to allow an image to be displayed. In the bottom emission type, the visible light emitted from the pixel array layer may be irradiated onto a rearward region behind the base substrate to allow an image to be displayed. In the dual emission type, the visible light emitted from the pixel array layer may be emitted to a forward region and a rearward region with respect to the base substrate. 
     The plurality of pixels may be respectively in a plurality of pixel areas defined by a plurality of pixel driving lines. Also, each of the plurality of pixels may include a pixel circuit, including at least two thin film transistors (TFTs) and at least one capacitor, and a light emitting device that emits light with a current supplied from the pixel circuit, but is not limited thereto. For example, the light emitting device may include an organic light emitting layer or a quantum dot light emitting layer, but is not limited thereto. As another example, the light emitting device may include a micro light emitting diode (LED), but is not limited thereto. 
     The encapsulation layer may protect the TFTs and the light emitting device from an external impact and may prevent water or moisture from penetrating into the light emitting device. The encapsulation layer may be replaced with an encapsulation substrate which is attached on the pixel array substrate by a filler surrounding the pixel array. If the filler is a transparent filler, the encapsulation substrate may be a transparent encapsulation substrate. 
     The display module  100  according to an embodiment of the present disclosure may further include a touch panel  130 . The touch panel  130  may include a touch electrode layer that is provided on the display panel  110 , and includes a touch electrode for sensing a user touch applied to the display module  100 . The touch electrode layer may sense a capacitance variation of the touch electrode caused by the user touch. For example, a mutual capacitance type where a plurality of touch driving electrodes and a plurality of touch sensing electrodes are provided to intersect one another or a self-capacitance type where only a plurality of touch sensing electrodes are provided may be applied, and an adhesive layer may be provided on an upper surface or a lower surface and may be attached on and fixed to an upper element or a lower element. 
     The display module  100  may further include a polarizing film  150  on the touch panel  130 . The polarizing film  150  may be attached on an upper surface of the touch panel  130  by a film attachment member. The polarizing film  150  may circularly polarize external light reflected by the TFT and/or the pixel driving lines provided on the pixel array substrate, thereby enhancing the visibility and contrast ratio of the display panel  110 . The polarizing film  150  may be between the encapsulation layer of the display panel  110  and the touch panel  130 . 
     The display panel  100  may further include a barrier layer between the encapsulation layer of the display panel  110  and the touch panel  130 . The barrier layer may prevent water or moisture and the like from penetrating into the pixel array. 
     The display module  100  may further include a color filter layer on an upper surface of the encapsulation layer of the display panel  110 . The color filter layer may include a color filter which is provided to overlap each of the plurality of pixels and transmits only a wavelength of a color set in each of the plurality of pixels. 
     The supporting member  300  may accommodate the display module  100 . In the present disclosure, the supporting member  300  may be referred to as a “cover bottom,” a “plate bottom,” a “back cover,” a “base frame,” a “metal frame,” a “metal chassis,” a “chassis base,” or an “m-chassis.” Therefore, the supporting member  300  may be a supporter for supporting the display panel  110  and may be implemented as any type of a frame or a plate structure each on the rear surface of the display apparatus. 
     For example, the supporting member  300  may support a rear surface and a side surface of the display panel. For example, the supporting member  300  may include a supporting member rear part  310  and a supporting member side part  330 . The supporting member rear part  310  may be on a rear surface of the display module  100 , and may cover the rear surface of the display module  100 . For example, the supporting member rear part  310  may cover a circuit accommodating space in the rear surface of the display module  100 . For example, the supporting member rear part  310  may be formed of the same material as that of a cover window  700 , or may be formed of a glass material differing from that of the cover window  700 . For example, the supporting member rear part  310  may be a rear cover, but the term is not limited thereto. For example, the supporting member rear part  310  may be provided independently from the supporting member side part  330 . 
     The supporting member side part  330  may surround each of side surfaces of the display module  100  to have a display accommodating space into which the display module  100  is accommodated. The supporting member side part  330  may have a frame shape or a corner-rounded shape, but is not limited thereto. For example, each of side surfaces of the supporting member  300  may be rounded to have a curvature radius, for enhancing a sense of beauty in design of the display apparatus. 
     The supporting member side part  330  may include first to fourth side surfaces  331  to  334  of the supporting member  300 . The first to fourth side surfaces  331  to  334  of the supporting member  300  may provide an accommodating space for accommodating the display module  100 . For example, the first to fourth side surfaces  331  to  334  of the supporting member  300  may provide a circuit accommodating space for accommodating peripheral circuits of an electronic apparatus including a battery and a circuit configuration of a driving circuit and the like. 
     The first side surface  331  of the supporting member  300  may be disposed in parallel with a first lengthwise direction X of the display apparatus. For example, the first side surface  331  of the supporting member  300  may be disposed vertical to a first side surface or a first long side of the supporting member rear part  310 . The first side surface  331  of the supporting member  300  may surround the first side surface or one short side of the display module  100 . 
     The second side surface  332  of the supporting member  300  may be disposed in parallel with the first side surface  331  of the supporting member  300 . For example, the second side surface  332  of the supporting member  300  may be disposed vertical to a second side surface or a second long side of the supporting member rear part  310 . The second side surface  332  of the supporting member  300  may surround the second side surface or the other short side of the display module  100 . 
     The third side surface  333  of the supporting member  300  may be disposed in parallel with a second lengthwise direction Y of the display apparatus intersecting or perpendicular to the first lengthwise direction X of the display apparatus. For example, the third side surface  333  of the supporting member  300  may be disposed vertical to a third side surface or a first short side of the supporting member rear part  310 . The third side surface  333  of the supporting member  300  may surround the third side surface or one long side of the display module  100 . 
     The fourth side surface  334  of the supporting member  300  may be disposed in parallel with the third side surface  333  of the supporting member  300 . For example, the fourth side surface  334  of the supporting member  300  may be disposed vertical to a fourth side surface or a second short side of the supporting member rear part  310 . The fourth side surface  334  of the supporting member  300  may surround the fourth side surface or the other long side of the display module  100 . 
     The supporting member  300  according to an embodiment of the present disclosure may further include a vibration device exposure part in the third side surface  333  of the supporting member  300 . For example, the vibration device exposure part may protrude from the third side surface  333  of the supporting member  300  and may be near the sound generating module  400 . Therefore, the sound generating module  400  attached to the rear surface of the display module  100  may be exposed at the outside through the vibration device exposure part. Also, a portion of a lower portion of the sound generating module  400  may be inserted into the vibration device exposure part. The vibration device exposure part may secure a vibration space for a vibration of the sound generating module  400  disposed in the display module  100 , and thus, the display apparatus may be slimmed and the sound generating module  400  may be easily placed. When a distance between the supporting member rear part  310  and the rear surface of the display module  100  is greater than the vibration space, the vibration device exposure part may be omitted. 
     The display apparatus  10  according to an embodiment of the present disclosure may further include a driving circuit  600  and a cover window  700 . 
     The driving circuit  600  may be in a circuit accommodating space in the support member  300 , and may be connected to the display panel  110  and the sound generating module  400 . The driving circuit  600  may include a panel driving circuit and a sound processing circuit. 
     The panel driving circuit may be mounted on the display panel  110  or the circuit board to display an image on the display panel  110 . The panel driving circuit may be connected to a pad part on the pixel array substrate of the display panel  110  and supply a driving signal and a data signal to the pixel driving lines, thereby displaying an image on each pixel. 
     The sound processing circuit may generate an audio signal based on an audio source and amplify the audio signal to generate a vibration driving signal. A vibration generating device  401  of the sound generating module  400  may vibrate based on the generated vibration driving signal. 
     The cover window  700  may be coupled or connected to the supporting member  300  to support the display module  100 . The cover window  700  may be formed of glass or a reinforced glass material. For example, the cover window  700  may have either a sapphire glass or a Gorilla glass or a stacked structure thereof. The cover window  700  may be attached to the front surface of the display module  100  via an adhesive member. The adhesive member may be, but is not limited to, an optically clear adhesive (OCA), an optically clear resin (OCR), or a pressure sensitive adhesive (PSA). 
     In one embodiment, the cover window  700  may cover a non-display area, except a display area, of the display module  100 . In another embodiment, the cover window  700  may include a transparent area overlapping the display area of the display module  100 , a light blocking area overlapping the non-display area of the display module  100 , and a design layer provided in the light blocking area to cover the non-display area of the display module  100 . The cover window  700  may be a support member, a window cover, or the like, and is not limited thereto. 
     The sound generating module  400  may be on the rear surface of the display module  100  (for example, the rear surface of the display panel  110 ). The sound generating module  400  may include the vibration generating device  401 . For example, the vibration generating device  401  may be on the rear surface of the display panel  110 . The sound generating module  400  may vibrate the display module  100  based on the vibration driving signal applied to the vibration generating device  401 . Therefore, the sound generating module  400  may output sound in a forward direction Z with respect to the display panel  110  based on a vibration of the display panel  110 . The vibration generating device  401  may generate a sound using the display panel  110  as a vibration plate. For example, the vibration generating device  401  may directly vibrate the display panel  100  to generate sound. The vibration generating device  401  may be referred to as an “actuator,” an “exciter,” or a “transducer,” but is not limited thereto. For example, the sound generating device  401  may be a sound device for outputting sound according to an electrical signal. 
     The vibration generating device  401  may include a piezoelectric material layer having a piezoelectric effect and an electrode at the piezoelectric material layer. The vibration generating device  401  may include the piezoelectric material layer, and thus, may be referred to as a “piezoelectric device.” 
     The piezoelectric material layer may include a piezoelectric material which vibrates with an electric field. Here, the piezoelectric material may have a characteristic in which as pressure is applied to or twisting occurs in a crystalline structure due to an external force, a potential difference is caused by dielectric polarization based on a relative position change of a positive (+) ion and a negative (−) ion, and vibration occurs due to an electric field based on an applied voltage. 
     The vibration generating device  401  may include a polymer material-containing piezoelectric material, a thin film material-having piezoelectric material, a composite material-having piezoelectric material, or a single crystalline ceramic or polycrystalline ceramic-having piezoelectric material. Examples of the polymer material-having piezoelectric material may include poly vinylidene fluoride (PVDF), polyvinylidene fluoride trifluoroethylene P(VDF-TrFe), and P(VDFTeFE). Examples of the thin film material-containing piezoelectric material may include ZnO, CdS, and AlN. Examples of the composite material-having piezoelectric material may include PZT-PVDF, PZT-silicon rubber, PZT-epoxy, PZT-foam polymer, and PZT-foam urethane. Examples of the single crystalline ceramic-having piezoelectric material may include α-AlPO 4 , α-SiO 2 , LiNbO 3 , Tb 2 (MoO 4 ) 3 , Li 2 B 4 O 7 , and ZnO. Examples of the polycrystalline ceramic-having piezoelectric material may include a PZT-based material, a PT-based material, a PZT-complex Perovskite-based material, and BaTiO 3 . 
     The vibration generating device  401  may have a shape such as a rectangular (e.g. quadrilateral) shape, a quadrate shape, a lozenge shape, or a parallelogram shape, but a shape is not limited thereto. 
     The sound generating module  400  may further include a reinforcement member. The reinforcement member may be further on an upper surface and/or a lower surface of the vibration generating device  401 , and thus, the vibration generating device  401  may be reduced or prevented from being detached or broken by an external impact. The reinforcement member may include a first reinforcement member  802  and a second reinforcement member  804 . The first reinforcement member  802  and the second reinforcement member  804  may be respectively on the upper surface and the lower surface of the vibration generating device  401 . Therefore, the vibration generating device  401  may be reduced or prevented from being detached or broken by an external impact. For example, the first reinforcement member  802  may be on the lower surface of the vibration generating device  401 , and the second reinforcement member  804  may be on the upper surface of the vibration generating device  401 . 
     The vibration generating device  401  may be coupled or connected to the reinforcement member by an adhesive member. For example, the vibration generating device  401  may be coupled or connected to the first reinforcement member  802  by a first adhesive member  403 . For example, the vibration generating device  401  may be coupled or connected to the second reinforcement member  804  by a second adhesive member  405 . The second reinforcement member  804  may be disposed on or coupled or connected to the rear surface of the display panel  110  by a third adhesive member  407 . 
     A circuit board  620  connected to the driving circuit  600  may be on the lower surface of the vibration generating device  401 . The driving circuit  600  may apply the vibration driving signal to the circuit board  620 , and thus, a signal may be applied to the vibration generating device  401 . A fourth adhesive member  404  may be disposed on a lower surface of the circuit board  620 . 
     When the reinforcement member is at the vibration generating device  401 , durability against an external impact may be enhanced, but a strain energy density based on a thickness or a height of the sound generating device  400  may vary. This will be described below with reference to  FIG.  3   . 
       FIG.  3    illustrates a simulation result of a strain energy density in a sound generating module according to an embodiment of the present disclosure. 
     In  FIG.  3   , a strain energy density (SED) (mJ/mm 3 ) represents a relationship between stress and a strain rate. It is shown that, as the strain energy density becomes lower, an impact resistance against an external impact becomes stronger. Here, “a” represents that only a vibration generating device is provided, “b” represents that the display apparatus of  FIG.  2    is implemented, and “c” represents that a reinforcement member is provided on an upper surface or a lower surface of a vibration generating device without an adhesive member in  FIG.  2   . With reference to  FIG.  3   , it may be seen that a strain energy density of a where only a vibration generating device is provided is 0.667 mJ/mm 3 , a strain energy density of b where an adhesive member and a reinforcement member are provided is 0.087 mJ/mm 3 , and a strain energy density of c where a reinforcement member is provided without an adhesive member is 0.037 mJ/mm 3 . It may be seen that a strain energy density is lower in a case, where an adhesive member and a reinforcement member are provided, than a case where only a vibration generating device is provided. It may be seen that a strain energy density of when a reinforcement member is provided without an adhesive member is almost similar to a strain energy density of when an adhesive member and a reinforcement member are provided. Accordingly, when an adhesive member and a reinforcement member are provided, it may be seen that an impact resistance against an external impact is enhanced. 
       FIGS.  4 A and  4 B  illustrate a sound generating module according to an embodiment of the present disclosure. 
       FIGS.  4 A and  4 B  illustrate another embodiment of a sound generating module for decreasing a height of the sound generating module to enhance a sound pressure level of the sound generating module. With reference to  FIG.  4 A , a sound generating module  410  according to an embodiment of the present disclosure may include a vibration generating device  401 , a first reinforcement member  802  on a lower surface of the vibration generating device  401 , and a circuit board  620 . An adhesive member may be on each of an upper surface and a lower surface of the vibration generating device  401 . For example, the sound generating module  410  may include a first adhesive member  403  on the lower surface of the vibration generating device  401  and a second adhesive member  405  on the upper surface of the vibration generating device  401 . A fourth adhesive member  404  may be on a lower surface of the circuit board  620 . 
     With reference to  FIG.  4 B , a sound generating module  420  according to an embodiment of the present disclosure may include a vibration generating device  401 , a second adhesive member  405  on an upper surface of the vibration generating device  401 , and a circuit board  620  on a lower surface of the vibration generating device  401 . 
       FIG.  5    illustrates a height and a sound pressure level in an impact test process performed on a sound generating module according to an embodiment of the present disclosure. 
     In  FIG.  5   , the abscissa axis (x-axis) represents an impact test height (mm), and the ordinate axis (y-axis) represents a sound pressure level (SPL) in decibel (dB). 
     An external impact test performed on a display apparatus may use, for example, a ball drop test. The ball drop test may be a test where a sound generating module impacted and a display panel including the same are fixed to a drop position, and by increasing a distance by 1 cm each time in a vertical direction to allow an iron bead having a weight of 100 g or 1,000 g to freely fall, the display performance of an impacted display panel is compared with the performance of the sound generating module before a driving test and the performance of the sound generating module after the driving test. In a case which desires to check a quantitative control issue and a secondary collision issue in association with free fall with respect to a finished (or final product) display apparatus to which a display panel and a sound generating module are applied, a free falling impact test with reliability added thereto may be used. The free falling impact test may be a test where, in a state where a finished display apparatus is applied, a falling target is transported by a certain height (for example, 1 m or more) and is freely fallen on a falling floor surface, and by using various sensors, a degree of damage of a freely fallen target is determined. However, embodiments are not limited thereto, and another method may be used as an impact test performed on a display panel and a sound generating module. 
     With reference to  FIG.  5   , PS represents the sound generating module of  FIG.  2   , each of SL, IL, CL, SH, CH, and IH represents the sound generating module of  FIG.  4 A , and each of P 1  and P 2  represents the sound generating module of  FIG.  4 B . PS and P 2  represent an example where a widthwise length of a vibration generating device is set to be longer than a lengthwise length thereof. P 1 , SH, CL, SL, IH, and CH represent an example where a widthwise length of a vibration generating device is set to be equal to a lengthwise length thereof. Each of PS, SH, CL, SL, IH, and CH represents a result obtained by measuring an external impact and a sound pressure level based on a material of a reinforcement member and a material of an adhesive member. In IH and CH each representing a result obtained by testing two sound generating modules, a test result is illustrated as two, and each of two test results is illustrated as a dotted-line circle. PS represents an example where a reinforcement member is formed of stainless steel and an adhesive member having a low elastic modulus is provided. SL represents an example where a reinforcement member is formed of stainless steel and an adhesive member having a low elastic modulus is provided. IL represents an example where a reinforcement member is formed of polyimide and an adhesive member having a low elastic modulus is provided. CL represents an example where a reinforcement member is formed of polycarbonate and an adhesive member having a low elastic modulus is provided. SH represents an example where a reinforcement member is formed of stainless steel and an adhesive member having a high elastic modulus is provided. CH represents an example where a reinforcement member is formed of polycarbonate and an adhesive member having a high elastic modulus is provided. IH represents an example where a reinforcement member is formed of polyimide and an adhesive member having a high elastic modulus is provided. 
     With reference to  FIG.  5   , it may be seen that a sound pressure level varies with respect to a size of a vibration generating device. For example, it may be seen that a sound pressure level is higher in P 1  than P 2 . Accordingly, it may be seen that a sound pressure level of a vibration generating device where a widthwise length is the same as a lengthwise length is higher than that of a vibration generating device where a widthwise length is longer than a lengthwise length. 
     In  FIG.  5   , it is shown that, as an impact test height increases, an impact resistance against an external impact increases. An impact resistance may vary based on whether a reinforcement member is provided. For example, it may be seen that an impact resistance is enhanced two to five times more in PS, SL, IL, CL, SH, IH, and CH, where a reinforcement member is provided, than P 1  and P 2  where a reinforcement member is not provided. 
     For example, when an adhesive member having a lower elastic modulus is applied, a sound pressure level may vary based on the number of reinforcement members and materials of the reinforcement members. For example, it may be seen that a sound pressure level is lower in PS, where two reinforcement members are provided, than SL, IL, and CL where one reinforcement member is provided. It may be seen that a sound pressure level of IL where a reinforcement member is formed of polyimide and a sound pressure level of CL where a reinforcement member is formed of polycarbonate are higher than that of SL where a reinforcement member is formed of stainless steel. It may be seen that a sound pressure level of CL where a reinforcement member is formed of polycarbonate is higher than that of IL where a reinforcement member is formed of polyimide. 
     For example, when an adhesive member having a high elastic modulus is applied, a sound pressure level may vary based on a material of the reinforcement member. For example, it may be seen that a sound pressure level of IH where a reinforcement member is formed of polyimide and a sound pressure level of CH where a reinforcement member is formed of polycarbonate are higher than that of SH where a reinforcement member is formed of stainless steel. It may be seen that a sound pressure level of IH where a reinforcement member is formed of polyimide is higher than that of CH where a reinforcement member is formed of polycarbonate. 
     For example, it is shown that an impact resistance varies based on a material of an adhesive member. For example, it may be seen that an impact resistance of each of SH, CH, and IH where an adhesive member having a high elastic modulus is provided is 2 to 2.5 times higher than that of each of PS, IL, SL, and CL where an adhesive member having a low elastic modulus is provided. 
     Therefore, when a reinforcement member is provided and an adhesive member having a high elastic modulus is provided, it may be seen that a sound pressure level and an impact resistance are enhanced. For example, in a case where a reinforcement member is formed of polyimide and an adhesive member having a high elastic modulus is provided, it may be seen that an impact resistance against an external impact is enhanced and a sound pressure level is enhanced. 
       FIG.  6    is a cross-sectional view taken along line I-I′ illustrated in  FIG.  1    according to another embodiment of the present disclosure. 
     With reference to  FIG.  6   , a display apparatus  20  according to an embodiment of the present disclosure may include a display module  100 , a supporting member  300 , and a sound generating module  430 . The display module  100  may include a display panel  110 . The display module  100 , the display panel  110 , and the supporting member  300  are as described above with reference to  FIGS.  1  and  2   , and thus, their descriptions are omitted or will be briefly given below. 
     As described above with reference to  FIGS.  4 A,  4 B, and  5   , when a reinforcement member is provided, an impact resistance may be enhanced, but a height of a sound generating module may increase, causing a problem where a sound pressure level is reduced and a thickness of the sound generating module is thickened. Also, since an adhesive for attaching a circuit board penetrates into an adhesive member, the present inventors have recognized that an adhesive surface between a reinforcement member and the adhesive member is not uniform, and due to this, the reinforcement member on a lower surface of a vibration generating device may be partially detached. Therefore, the inventors have performed various experiments for implementing a sound generating module where a thickness thereof does not increase, an impact resistance is enhanced, and a problem caused by a reinforcement member does not occur. Through the various experiments, the present inventors have invented a sound generating module having a new structure, in which a thickness of a sound generating module does not increase, an impact resistance is enhanced, and a defect caused by the partial detachment of a reinforcement member does not occur. 
     As described above with reference to  FIGS.  4 A,  4 B, and  5   , when a reinforcement member is formed of polyimide, it may be seen that an impact resistance against an external impact is enhanced. Therefore, the inventors have performed various experiments for applying polyimide to a reinforcement member. This will be described below. 
     With reference to  FIG.  6   , a sound generating module  430  according to an embodiment of the present disclosure may include a vibration generating device  431  and a circuit board  625  on a lower surface of the vibration generating device  431 . Through various experiments, the present inventors have recognized that a circuit board is formed of polyimide and the polyimide may be applied to form a reinforcement member, without any increase in thickness of a sound generating module. For example, the circuit board  625  may be a flexible printed circuit board (FPCB), but is not limited thereto. For example, the circuit board  625  may be formed of polyimide. The circuit board  625  may have the same size as that of the vibration generating device  401  and may be implemented as a reinforcement member. When the circuit board  625  may have the same size as that of the vibration generating device  401 , the circuit board  625  may be easily disposed in process compared to  FIG.  2   . Therefore, since a circuit board configures a reinforcement member, a thickness of a sound generating module may not increase, and an impact resistance against an external impact may be enhanced. 
     The vibration generating device  431  may be disposed on or coupled or connected to the circuit board  625  and the display panel  110  by an adhesive member. For example, the vibration generating device  431  may be disposed on or coupled or connected to the circuit board  625  by a first adhesive member  433 . For example, the vibration generating device  431  may be disposed on or coupled or connected to the display panel  110  by a second adhesive member  435 . An elastic modulus (or a young&#39;s modulus) of the first adhesive member  433  may differ from that of the second adhesive member  435 . For example, the elastic modulus of the first adhesive member  433  may be higher than that of the second adhesive member  435 . For example, the elastic modulus of the first adhesive member  433  may be 1 GPa to 200 GPa. For example, an elastic modulus of the second adhesive member  435  may be 0.1 MPa to 30 MPa. For example, the second adhesive member  435  adjacent to the display panel  110  may be formed of a material having an elastic modulus which is lower than that of the first adhesive member  433 , so as not to affect a sound pressure level corresponding to a low frequency when the sound generating module  430  vibrates. For example, the first adhesive member  433  may be formed of adhesive resin, but is not limited thereto. For example, the first adhesive member  433  may be configured as an adhesive member having conductivity. For example, the first adhesive member  433  may include a thermocurable material including a conductive filler, but is not limited thereto. For example, the first adhesive member  433  may include a thermocurable acrylic material including a conductive filler, but is not limited thereto. The circuit board  625  may be disposed on or coupled or connected to the vibration generating device  431  by the first adhesive member  433 . Therefore, an adhesive member on at least one electrode and an adhesive member for coupling or connecting a circuit board to a vibration generating device may be provided as one adhesive member, and thus, a manufacturing process may be simplified. For example, the second adhesive member  435  may include a sticking agent or an adhesive each including at least one of a double-sided tape, acrylic resin, epoxy-based resin, silicon-based resin, polyurethane-based resin, and polyvinyl alcohol-based resin, but is not limited thereto. The vibration generating device  431  may be disposed on or coupled or connected to the display panel  110  by the second adhesive member  435 . The first adhesive member  433  and the second adhesive member  435  may each be a sticking member or a sticking agent, but the term is not limited thereto. Therefore, since a reinforcement member is provided and an adhesive member having a high elastic modulus is provided, an impact resistance against an external impact may be enhanced, and a sound pressure level may be enhanced. 
     The circuit board  625  may be on a lower surface of the vibration generating device  431 . The circuit board  625  may include a base film  610 , a first electrode  612 , a second electrode  613 , and a passivation layer  611 . The base film  610  may be on the lower surface of the vibration generating device  431 . The base film  610  may be formed of a polyimide-based material. The first electrode  612  and the second electrode  613  may be on the lower surface of the vibration generating device  431 . For example, the first electrode  612  and the second electrode  613  may be on an upper surface and a lower surface of the base film  610 . The first electrode  612  may be an electrode for applying a signal to the vibration generating device  431  and may be a VDD electrode or a common electrode. The second electrode  613  may be a ground electrode. The first electrode  612  and the second electrode  613  may be formed of an opaque metal material which has relatively low resistance and has good heat dissipation characteristic. However, embodiments are not limited thereto. For example, the first electrode  612  and the second electrode  613  may be formed of a transparent conductive material or a conductive polymer material. The passivation layer  611  may be disposed for protecting a line between the first electrode  612  and the second electrode  613 . For example, the passivation layer  611  may be in a region except the first electrode  612  and the second electrode  613 , but is not limited thereto. For example, the passivation layer  611  may be on each of the upper surface and the lower surface of the base film  610 . For example, the first electrode  612  and the second electrode  613  may be spaced apart from each other on the lower surface of the vibration generating device  431 , and the base film  610  and the passivation layer  611  may be between the first electrode  612  and the second electrode  613 . The passivation layer  611  may be configured as a type where a sticking agent or an adhesive is coated or formed on a polyimide-based film, but is not limited thereto. For example, the sticking agent or the adhesive may include at least one of a cyanoacrylate adhesive, an epoxy-based adhesive, an acrylate adhesive, and an acrylic adhesive, but is not limited thereto. 
       FIG.  7    is a cross-sectional view taken along line I-I′ illustrated in  FIG.  1    according to another embodiment of the present disclosure. 
     With reference to  FIG.  7   , a display apparatus  30  according to an embodiment of the present disclosure may include a display module  100 , a supporting member  300 , and a sound generating module  450 . The display module  100  may include a display panel  110 . The display module  100 , the display panel  110 , and the supporting member  300  are as described above with reference to  FIGS.  1  and  2   , and thus, their descriptions are omitted or will be briefly given below. 
     A sound generating module  450  according to an embodiment of the present disclosure may include a vibration generating device  451  and a circuit board  630  on a lower surface of the vibration generating device  451 . The vibration generating device  451  may be disposed on or coupled or connected to the circuit board  630  and the display panel  110  by an adhesive member. For example, the vibration generating device  451  may be disposed on or coupled or connected to the circuit board  630  by a first adhesive member  453 . For example, the vibration generating device  451  may be disposed on or coupled or connected to the display panel  110  by a second adhesive member  455 . An elastic modulus (or a young&#39;s modulus) of the first adhesive member  453  may differ from that of the second adhesive member  455 . For example, the elastic modulus of the first adhesive member  453  may be higher than that of the second adhesive member  455 . For example, the elastic modulus of the first adhesive member  453  may be 1 GPa to 200 GPa. For example, an elastic modulus of the second adhesive member  455  may be 0.1 MPa to 30 MPa. For example, the second adhesive member  455  adjacent to the display panel  110  may be formed of a material having an elastic modulus which is lower than that of the first adhesive member  453 , so as not to affect a sound pressure level corresponding to a low frequency when the sound generating module  450  vibrates. For example, the first adhesive member  453  may include a sticking agent or an adhesive each including at least one of a cyanoacrylate adhesive, an epoxy-based adhesive, an acrylate adhesive, and an acrylic adhesive, but is not limited thereto. For example, the second adhesive member  455  may include a sticking agent or an adhesive each including at least one of a double-sided tape, acrylic resin, epoxy-based resin, silicon-based resin, polyurethane-based resin, and polyvinyl alcohol-based resin, but is not limited thereto. The first adhesive member  453  and the second adhesive member  455  may each be a sticking member or a sticking agent, but the term is not limited thereto. Therefore, since a reinforcement member is provided and an adhesive member having a high elastic modulus is provided, an impact resistance against an external impact may be enhanced, and a sound pressure level may be enhanced. 
     The circuit board  630  may be on a lower surface of the vibration generating device  451 . The circuit board  630  may include a base film  610 , a first electrode  612 , a second electrode  613 , and a passivation layer  611 . The base film  610  may be on the lower surface of the vibration generating device  451 . The base film  610  may be formed of a polyimide-based material. The first electrode  612  and the second electrode  613  may be on the lower surface of the vibration generating device  451 . For example, the first electrode  612  and the second electrode  613  may be on an upper surface and a lower surface of the base film  610 . The first electrode  612  may be an electrode for applying a signal to the vibration generating device  451  and may be a VDD electrode or a common electrode. The second electrode  613  may be a ground electrode. The first electrode  612  and the second electrode  613  may be formed of an opaque metal material which has relatively low resistance and has good heat dissipation characteristic. However, embodiments are not limited thereto, and the first electrode  612  and the second electrode  613  may be formed of a transparent conductive material or a conductive polymer material. The passivation layer  611  may be disposed for protecting a line between the first electrode  612  and the second electrode  613 . For example, the passivation layer  611  may be disposed in a region except the first electrode  612  and the second electrode  613 , but is not limited thereto. For example, the passivation layer  611  may be on each of the upper surface and the lower surface of the base film  610 . For example, the first electrode  612  and the second electrode  613  may be spaced apart from each other on the lower surface of the vibration generating device  431 , and the base film  610  and the passivation layer  611  may be between the first electrode  612  and the second electrode  613 . The passivation layer  611  may be configured as a type where a sticking agent or an adhesive is coated on a polyimide-based film, but is not limited thereto. For example, the sticking agent or the adhesive may include at least one of a cyanoacrylate adhesive, an epoxy-based adhesive, an acrylate adhesive, and an acrylic adhesive, but is not limited thereto. 
     A fifth adhesive member  609  may be on the first electrode  612  and the second electrode  613 . For example, the first electrode  612  and the second electrode  613  may be attached to the lower surface of the vibration generating device  451  by the fifth adhesive member  609 . The passivation layer  611  may be attached to the lower surface of the vibration generating device  451  by each of the first adhesive member  453  and the fifth adhesive member  609 . For example, the fifth adhesive member  609  may be formed of a material differing from that of the first adhesive member  453 . For example, the fifth adhesive member  609  may be formed of a conductive adhesive. For example, the conductive adhesive may include thermocurable (e.g., thermosetting) resin including a conductive filler or a thermocurable polymer including a conductive filler, but is not limited thereto. For example, the first adhesive member  453  may be formed of a material having a high elastic modulus. An adhesive may be attached to the circuit board  630 . The circuit board  630  may be attached to the display panel through a compression process and a curing process in a case which attaches the circuit board  630  to the display panel, and in the compression process and the curing process, the adhesive of the circuit board  630  may flow out to the outside. A member  631  may be further provided between the first adhesive member  453  and the fifth adhesive member  609 , for reducing or preventing a defect such as the partial detachment of the circuit board  630  caused by the adhesive. Therefore, the member  631  may separate the first adhesive member  453  from the fifth adhesive member  609 . For example, the member  631  may be formed of a polyimide-based material or a polycarbonate-based material, but is not limited thereto. Accordingly, since the member  631  is provided between the first adhesive member  453  and the fifth adhesive member  609 , the adhesive of the circuit board  630  may be reduced or prevented from flowing out to the outside in the compression process and the curing process. Therefore, an adhesive surface between the circuit board  630  and the first adhesive member  453  may be uniform, and thus, a defect such as the partial detachment of the circuit board  630  may be prevented. 
     A sixth adhesive member  608  may be between the circuit board  630  and the member  631 . For example, the sixth adhesive member  608  may be between the base film  610  and the member  631 . The member  631  may be disposed on or coupled or connected to the circuit board  630  by the sixth adhesive member  608 . The sixth adhesive member  608  may be formed of an acrylic material or an epoxy-based material, but is not limited thereto. 
       FIGS.  8 A to  8 C  are detailed views of  FIG.  7    according to another embodiment of the present disclosure. 
     With reference to  FIGS.  8 A to  8 C , a sound generating module  450  may be on a lower surface of the display module  100 . A first electrode  612  and a second electrode  613  may be disposed at a vibration generating device  451 . For example, the first electrode  612  and the second electrode  613  may be on a lower surface of the vibration generating device  451 . The first electrode  612  may be a VDD electrode or a common electrode, and the second electrode  613  may be a ground electrode. When the first electrode  612  is disconnected, the third electrode  614  may be an auxiliary electrode and may be a VDD electrode. 
     With reference to  FIG.  8 C , in a circuit board  630 , a first adhesive member  453  and a fifth adhesive member  609  may be on a base film  610 . A member  631  may be between the first adhesive member  453  and the fifth adhesive member  609 . A right portion of  FIG.  8 C  illustrates a “C” portion of  FIG.  8 A . For example, the first electrode  612 , the second electrode  613 , and a passivation layer  611  are illustrated. The passivation layer  611  may be provided for protecting a line between the first electrode  612  and the second electrode  613 . For example, the passivation layer  611  may be in a region except the first electrode  612  and the second electrode  613 , but is not limited thereto.  FIGS.  8 A to  8 C  may be identically applied to the sound generating module of  FIG.  6   . For example, elements other than the fifth adhesive member  609 , the member  631 , and the sixth adhesive member  608  may be identically applied. 
       FIG.  9    is a rear view of a display apparatus according to another embodiment of the present disclosure. 
     With reference to  FIG.  9   , each of a plurality of sound generating modules  430  and  450  may be on an upper side of a rear surface of a display panel  110 . The display panel  110  may include a first short side, a second short side facing the first short side, and a long side vertical to the first short side or the second short side. For example, the first short side and the second short side may be in a widthwise direction of the display panel  110 , and the long side may be in a lengthwise direction of the display panel  110 . The widthwise direction and the lengthwise direction may be interchangeable. For example, a distance d 1  between a center of each of a plurality of vibration generating devices  431  and  451  and the first short side of the display panel  110  may be ¼ to ⅓ of the long side of the display panel  110 . When the sound generating modules  430  or  450  are on the upper portion of the rear surface of the display panel  110 , a sound pressure level may be more improved than when the sound generating modules  430  or  450  are disposed at a center of the display panel  110 . 
       FIG.  10    is a perspective view illustrating a display apparatus according to another embodiment of the present disclosure.  FIG.  11    is a cross-sectional view taken along line II-IF illustrated in  FIG.  10   . 
     With reference to  FIGS.  10  and  11   , a display apparatus  40  according to an embodiment of the present disclosure may include a display module  100 , a supporting member  300 , a first sound generating module  430 , and a second sound generating module  530 . The display module  100  may include a display panel  110 . The display module  100 , the display panel  110 , and the supporting member  300  are as described above with reference to  FIGS.  1  and  2   , and thus, their descriptions are omitted or will be briefly given below. 
     With reference to  FIGS.  10  and  11   , the display apparatus  40  according to an embodiment of the present disclosure may include the first sound generating module  430  and the second sound generating module  530 . A sound generating module, a vibration generating device, and a circuit board each described above with reference to  FIG.  6    may respectively be a first sound generating module, a first vibration generating device, and a first circuit board each illustrated in  FIGS.  10  to  11   . 
     The first sound generating module  430  according to an embodiment of the present disclosure may include a first vibration generating device  431  and a first circuit board  625  on a lower surface of the first vibration generating device  431 . 
     The first vibration generating device  431  may be disposed on or coupled or connected to the first circuit board  625  and the display panel  110  by an adhesive member. For example, the first vibration generating device  431  may be disposed on or coupled or connected to the first circuit board  625  by a first adhesive member  433 . For example, the first vibration generating device  431  may be disposed on or coupled or connected to the display panel  110  by a second adhesive member  435 . An elastic modulus of the first adhesive member  433  may differ from that of the second adhesive member  435 . For example, the second adhesive member  435  adjacent to the display panel  110  may be formed of a material having an elastic modulus which is lower than that of the first adhesive member  433 , so as not to affect a sound pressure level corresponding to a low frequency when the first sound generating module  430  vibrates. For example, the first adhesive member  433  and the second adhesive member  435  may each include a sticking member or a sticking agent, but the term is not limited thereto. For example, a middle-pitched sound band may be 200 Hz to 3 kHz, a high-pitched sound band may be 3 kHz or more, and a low-pitched sound band may be 200 Hz or less. However, the present embodiment is not limited thereto. 
     The second sound generating module  530  according to an embodiment of the present disclosure may include a second vibration generating device  531  and a second circuit board  626  on a lower surface of the second vibration generating device  531 . 
     The second vibration generating device  531  may be disposed on or coupled or connected to the second circuit board  626  and the display panel  110  by an adhesive member. For example, the second vibration generating device  531  may be disposed on or coupled or connected to the second circuit board  626  by a third adhesive member  533 . For example, the second vibration generating device  531  may be disposed on or coupled or connected to the display panel  110  by a fourth adhesive member  535 . An elastic modulus of the third adhesive member  533  may differ from that of the fourth adhesive member  535 . For example, the elastic modulus of the third adhesive member  533  may be higher than that of the fourth adhesive member  535 . For example, the elastic modulus of the third adhesive member  533  may be 1 GPa to 200 GPa. For example, an elastic modulus of the fourth adhesive member  535  may be 0.1 MPa to 30 MPa. For example, the fourth adhesive member  535  adjacent to the display panel  110  may be formed of a material having an elastic modulus which is lower than that of the third adhesive member  533 , so as not to affect a sound pressure level corresponding to a low frequency when the second sound generating module  530  vibrates. For example, the third adhesive member  533  may be formed of adhesive resin, but is not limited thereto. For example, the third adhesive member  533  may be configured as an adhesive member having conductivity. For example, the third adhesive member  533  may include a thermocurable material including a conductive filler, but is not limited thereto. For example, the third adhesive member  533  may include a thermocurable acrylic material including a conductive filler, but is not limited thereto. The second circuit board  626  may be disposed on or coupled or connected to the second vibration generating device  531  by the third adhesive member  533 . Therefore, an adhesive member disposed on at least one electrode and an adhesive member for coupling a circuit board to a vibration generating device may be provided as one adhesive member, and thus, a manufacturing process may be simplified. 
     For example, the fourth adhesive member  535  may include a sticking agent or an adhesive each including at least one of a double-sided tape, acrylic resin, epoxy-based resin, silicon-based resin, polyurethane-based resin, and polyvinyl alcohol-based resin, but is not limited thereto. The third adhesive member  533  and the fourth adhesive member  535  may each be a sticking member or a sticking agent, but the term is not limited thereto. Therefore, since a reinforcement member is provided and an adhesive member having a high elastic modulus is provided, an impact resistance against an external impact may be enhanced, and a sound pressure level may be enhanced. 
     The first circuit board  625  may be on a lower surface of the first vibration generating device  431 . The first circuit board  625  may include a base film  610 , a first electrode  612 , a second electrode  613 , and a passivation layer  611 . The first circuit board  625  has been described above with reference to  FIG.  6   , and thus, its detailed description is omitted and a second circuit board will be described below. The second circuit board  626  may be on a lower surface of the second vibration generating device  531 . The second circuit board  626  may include a base film  610 , a first electrode  612 , a second electrode  613 , and a passivation layer  611 . The base film  610  may be on a lower surface of the second vibration generating device  531 . The base film  610  may be formed of a polyimide-based material. The first electrode  612  and the second electrode  613  may be on the lower surface of the second vibration generating device  531 . For example, the first electrode  612  and the second electrode  613  may be on an upper surface and a lower surface of the base film  610 . The first electrode  612  may be an electrode for applying a signal to the second vibration generating device  531  and may be a VDD electrode or a common electrode. The second electrode  613  may be a ground electrode. The first electrode  612  and the second electrode  613  may be formed of an opaque metal material which has relatively low resistance and has good heat dissipation characteristic. However, embodiments are not limited thereto. For example, the first electrode  612  and the second electrode  613  may be formed of a transparent conductive material or a conductive polymer material. The passivation layer  611  may be disposed for protecting a line between the first electrode  612  and the second electrode  613 . For example, the passivation layer  611  may be in a region except the first electrode  612  and the second electrode  613 , but is not limited thereto. For example, the passivation layer  611  may be on each of the upper surface and the lower surface of the base film  610 . For example, the passivation layer  611  may be configured as a type where a sticking agent or an adhesive is coated on a polyimide-based film, but is not limited thereto. For example, the sticking agent or the adhesive may include at least one of a cyanoacrylate adhesive, an epoxy-based adhesive, an acrylate adhesive, and an acrylic adhesive, but is not limited thereto. 
       FIG.  12    is a cross-sectional view taken along line II-II′ illustrated in  FIG.  10    according to another embodiment of the present disclosure. 
     With reference to  FIG.  12   , a display apparatus  50  according to an embodiment of the present disclosure may include a display module  100 , a supporting member  300 , a first sound generating module  450 , and a second sound generating module  550 . The display module  100  may include a display panel  110 . The display module  100 , the display panel  110 , and the supporting member  300  are as described above with reference to  FIGS.  1  and  2   , and thus, their descriptions are omitted or will be briefly given below. The sound generating module, the vibration generating device, and the circuit board each described above with reference to  FIGS.  7  and  8    may respectively be a first sound generating module, a first vibration generating device, and a first circuit board each illustrated in  FIG.  12   . 
     The first sound generating module  450  according to an embodiment of the present disclosure may include a first vibration generating device  451  and a circuit board  630  on a lower surface of the first vibration generating device  451 . The first vibration generating device  451  may be disposed on or coupled or connected to the circuit board  630  and the display panel  110  by an adhesive member. For example, the first vibration generating device  451  may be disposed on or coupled or connected to the circuit board  630  by a first adhesive member  453 . For example, the first vibration generating device  451  may be disposed on or coupled or connected to the display panel  110  by a second adhesive member  455 . An elastic modulus of the first adhesive member  453  may differ from that of the second adhesive member  455 . For example, the elastic modulus of the first adhesive member  453  may be higher than that of the second adhesive member  455 . For example, the elastic modulus of the first adhesive member  453  may be 1 GPa to 200 GPa. For example, an elastic modulus of the second adhesive member  455  may be 0.1 MPa to 30 MPa. For example, the second adhesive member  455  adjacent to the display panel  110  may be formed of a material having an elastic modulus which is lower than that of the first adhesive member  453 , so as not to affect a sound pressure level corresponding to a low frequency when the first sound generating module  450  vibrates. For example, the first adhesive member  453  may include a sticking agent or an adhesive each including at least one of a cyanoacrylate adhesive, an epoxy-based adhesive, an acrylate adhesive, and an acrylic adhesive, but is not limited thereto. For example, the second adhesive member  455  may include a sticking agent or an adhesive each including at least one of a double-sided tape, acrylic resin, epoxy-based resin, silicon-based resin, polyurethane-based resin, and polyvinyl alcohol-based resin, but is not limited thereto. The first adhesive member  453  and the second adhesive member  455  may each be a sticking member or a sticking agent, but the term is not limited thereto. 
     The second sound generating module  550  according to an embodiment of the present disclosure may include a second vibration generating device  551  and a second circuit board  632  on a lower surface of the second vibration generating device  551 . 
     The second vibration generating device  551  may be disposed on or coupled or connected to the second circuit board  632  and the display panel  110  by an adhesive member. For example, the second vibration generating device  551  may be disposed on or coupled or connected to the second circuit board  632  by a third adhesive member  553 . For example, the second vibration generating device  551  may be disposed on or coupled or connected to the display panel  110  by a fourth adhesive member  555 . An elastic modulus of the third adhesive member  533  may differ from that of the fourth adhesive member  555 . For example, the elastic modulus of the third adhesive member  553  may be higher than that of the fourth adhesive member  555 . For example, the elastic modulus of the third adhesive member  553  may be 1 GPa to 200 GPa. For example, an elastic modulus of the fourth adhesive member  555  may be 0.1 MPa to 30 MPa. For example, the fourth adhesive member  555  adjacent to the display panel  110  may be formed of a material having an elastic modulus which is lower than that of the third adhesive member  553 , so as not to affect a sound pressure level corresponding to a low frequency when the second sound generating module  550  vibrates. For example, the third adhesive member  553  may include a sticking agent or an adhesive each including at least one of a cyanoacrylate adhesive, an epoxy-based adhesive, an acrylate adhesive, and an acrylic adhesive, but is not limited thereto. For example, the fourth adhesive member  555  may include a sticking agent or an adhesive each including at least one of a double-sided tape, acrylic resin, epoxy-based resin, silicon-based resin, polyurethane-based resin, and polyvinyl alcohol-based resin, but is not limited thereto. The third adhesive member  553  and the fourth adhesive member  555  may each be a sticking member or a sticking agent, but the term is not limited thereto. Therefore, since a reinforcement member is provided and an adhesive member having a high elastic modulus is provided, an impact resistance against an external impact may be enhanced, and a sound pressure level may be enhanced. 
     The first circuit board  630  may be on a lower surface of the first vibration generating device  451 . The first circuit board  630  may include a base film  610 , a first electrode  612 , a second electrode  613 , and a passivation layer  611 . The first circuit board  630  has been described above with reference to  FIG.  7   , and thus, its detailed description is omitted and a second circuit board will be described below. The second circuit board  630  may be on a lower surface of the second vibration generating device  531 . The second circuit board  632  may include a base film  610 , a first electrode  612 , a second electrode  613 , and a passivation layer  611 . The base film  610  of each of the first circuit board  630  and the second circuit board  632  may be formed of a polyimide-based material. The first electrode  612  and the second electrode  613  may be on a lower surface of the second vibration generating device  551 . The first electrode  612  may be an electrode for applying a signal to the second vibration generating device  551  and may be a VDD electrode or a common electrode. The second electrode  613  may be a ground electrode. The first electrode  612  and the second electrode  613  may be formed of an opaque metal material which has relatively low resistance and has good heat dissipation characteristic. However, embodiments are not limited thereto. For example, the first electrode  612  and the second electrode  613  may be formed of a transparent conductive material or a conductive polymer material. The passivation layer  611  may be disposed for protecting a line between the first electrode  612  and the second electrode  613 . For example, the passivation layer  611  may be in a region except the first electrode  612  and the second electrode  613 , but is not limited thereto. For example, the passivation layer  611  may be on each of the upper surface and the lower surface of the base film  610 . For example, the passivation layer  611  may be configured as a type where a sticking agent or an adhesive is coated on a polyimide-based film, but is not limited thereto. For example, the sticking agent or the adhesive may include at least one of a cyanoacrylate adhesive, an epoxy-based adhesive, an acrylate adhesive, and an acrylic adhesive, but is not limited thereto. 
     A fifth adhesive member  609  may be on the first electrode  612  and the second electrode  613 . For example, the fifth adhesive member  609  may be formed of a material differing from that of the third adhesive member  553 . For example, the fifth adhesive member  609  may be formed of a conductive adhesive. For example, the conductive adhesive may include thermocurable resin including a conductive filler or a thermocurable polymer including a conductive filler, but is not limited thereto. For example, the third adhesive member  553  may be formed of a material having a high elastic modulus. An adhesive may be attached to the second circuit board  632 . The second circuit board  632  may be attached to the display panel through a compression process and a curing process in a case which attaches the second circuit board  632  on the display panel, and in the compression process and the curing process, the adhesive of the second circuit board  632  may flow out to the outside. A member  631  may be further provided between the third adhesive member  553  and the fifth adhesive member  609 , for reducing or preventing a defect such as the partial detachment of the second circuit board  632  caused by the adhesive. Therefore, the member  631  may separate the third adhesive member  553  from the fifth adhesive member  609 . For example, the member  631  may be formed of a polyimide-based material or a polycarbonate-based material, but is not limited thereto. Accordingly, since the member  631  is provided between the third adhesive member  553  and the fifth adhesive member  609 , the adhesive of the second circuit board  632  may be reduced or prevented from flowing out to the outside in the compression process and the curing process. Therefore, an adhesive surface between the second circuit board  632  and the third adhesive member  553  may be uniform, and thus, a defect such as the partial detachment of the second circuit board  632  may be prevented. 
     A sixth adhesive member  608  may be between the second circuit board  632  and the member  631 . For example, the sixth adhesive member  608  may be between the base film  610  and the member  631 . The member  631  may be disposed on or coupled or connected to the second circuit board  632  by the sixth adhesive member  608 . The sixth adhesive member  608  may be formed of an acrylic material or an epoxy-based material, but is not limited thereto. 
       FIG.  13    is a rear view of a display panel according to another embodiment of the present disclosure. 
     With reference to  FIG.  9   , each of a plurality of first sound generating modules  430  and  450  may be on an upper portion of a rear surface of a display panel  110 . The display panel  110  may include a first short side, a second short side facing the first short side, and a long side vertical to the first short side or the second short side. For example, the first short side and the second short side may be in a widthwise direction of the display panel  110 , and the long side may be in a lengthwise direction of the display panel  110 . The widthwise direction and the lengthwise direction may be interchangeable. For example, a distance d 1  between a center of each of a plurality of first vibration generating devices  431  and  451  and the first short side of the display panel  110  may be ¼ to ⅓ of the long side of the display panel  110 . When the first sound generating modules  430  and  450  are on the upper portion of the rear surface of the display panel  110 , a sound pressure level may be more improved than when the sound generating modules  430  and  450  are disposed at a center of the display panel  110 . Each of a plurality of second sound generating modules  530  and  550  may be disposed on a lower portion of the rear surface of the display panel  110 . For example, a distance d 2  between a center of each of a plurality of second vibration generating devices  531  and  552  and an end of the second short side of the display panel  110  may be ¼ to ⅓ of the long side of the display panel  110 . The second short side of the display panel  110  may be a side facing the first short side. The second sound generating modules  530  and  550  may be disposed to be symmetrical with the first sound generating modules  430  and  450  with respect to a center of the display module  100 . 
       FIG.  14    is a rear view of a display panel according to another embodiment of the present disclosure. 
     With reference to  FIG.  14   , a display apparatus  60  according to an embodiment of the present disclosure may include a plurality of first sound generating modules  430  and  450  and a plurality of second sound generating modules  530  and  550 . The first sound generating modules  430  and  450  may vibrate a first rear region A 1  of a display module  100  based on a vibration driving signal provided from circuit boards  625  and  630  of a driving circuit  600 . The first rear region A 1  may be a rear right region or a region between a rear center portion or a center portion CL 1  of the display module  100  and one end of the display module  100  with respect to a lengthwise direction or a long-side direction X of the display module  100 . For example, the first rear region A 1  may be a right upper periphery region or a left upper periphery region or other periphery region of the display module  100  with respect to the lengthwise direction or the long-side direction X of the display module  100 . 
     The second sound generating modules  530  and  550  may vibrate a second rear region A 2  of the display module  100  based on the vibration driving signal from circuit boards  626  and  632  of the driving circuit  600 . The second rear region A 2  may be a rear right region or a region between the center portion CL 1  of the display module  100  and the other end of the display module  100  with respect to the lengthwise direction or a long-side direction X of the display module  100 . For example, the second rear region A 2  may be a left periphery region or a right periphery region or the other periphery region of the display module  100  with respect to the lengthwise direction or the long-side direction X of the display module  100 . The second sound generating modules  530  and  550  may be disposed to be symmetrical with the first sound generating modules  430  and  450 . For example, the second sound generating modules  530  and  550  may be disposed to be symmetrical with the first sound generating modules  430  and  450  with respect to the center portion CL 1  of the display module  100 . 
     The display apparatus  60  according to an embodiment of the present disclosure may further include a partition  900 . The partition  900  may be disposed at the rear center portion CL 1  of the display module  100 . For example, the partition  900  may be between the first sound generating modules  430  and  450  and the second sound generating modules  530  and  550 . For example, the partition  900  may spatially separate or divide the first rear region A 1  overlapping the first sound generating modules  430  and  450  and the second rear region A 2  overlapping the second sound generating modules  530  and  550  at the rear surface of the display panel  110 , thereby reducing or preventing interference between sounds generated by the first rear region A 1  and the second rear region A 2 . The partition  900  may spatially separate or divide the first rear region A 1  and the second rear region A 2  each provided in a rear surface of the display module  100  (or the display panel  110 ) to prevent interference between the sounds generated by the first rear region A 1  and the second rear region A 2 . Accordingly, the partition  900  may separate sounds generated by first vibration generating devices  431  and  451  and second vibration generating devices  531  and  551  to reduce or prevent interference between the generated sounds, thereby allowing a 2.0-channel sound to be output to a forward region with respect to the display module  100  based on a vibration of the display module  100 . 
     The partition  900  may be between a rear surface of the display module  100  and a supporting member rear part  310  of the supporting member  300 . A rear surface of the partition  900  may be attached to the supporting member rear part  310  of the supporting member  300 , and a front surface of the partition  900  may be attached to the rear surface of the display module  100 , may contact the rear surface of the display module  100  in a contactless type. For example, the partition  900  may be formed of a double-sided tape, a double-sided foam pad, a single-sided tape, a single-sided foam pad, an adhesive, and/or a bond, but is not limited thereto. The partition  900  may be referred to as an “enclosure” or a “baffle,” but the term is not limited thereto. 
     The sound generating device described above with reference to  FIGS.  6  to  14    may be applied to a speaker and a receiver such as an electronic apparatus. A receiver may transfer a call voice based on an electronic apparatus to ears of a user. For example, when the first sound generating modules  430  and  450  operates as a receiver such as an electronic apparatus, the first sound generating modules  430  and  450  may receive the vibration driving signal from the sound processing circuit. For example, when the first sound generating modules  430  and  450  are applied to a receiver such as an electronic apparatus, the first sound generating modules  430  and  450  may transfer a sound of the low-pitched sound band and a sound of the high-pitched sound band, improved by the first vibration generating device and the second vibration generating device, to a user, or the user may receive the improved sound of the low-pitched sound band and the improved sound of the high-pitched sound band, thereby providing a display apparatus for providing an enhanced call voice to a user. For example, when each of the first sound generating modules  430  and  450  and the second sound generating modules  530  and  550  operates as a speaker such as an electronic apparatus, each of the first sound generating modules  430  and  450  and the second sound generating modules  530  and  550  may receive the vibration driving signal from the sound processing circuit. Accordingly, a sound of the low-pitched sound band and a sound of the high-pitched sound band improved by the first vibration generating module and the second vibration generating module may be transferred to the user. 
       FIGS.  15 A and  15 B  are rear views of a display panel according to another embodiment of the present disclosure. 
     With reference to  FIG.  15 A , a display apparatus  70  according to an embodiment of the present disclosure may include a plurality of first sound generating modules  430  and  450  and a plurality of second sound generating modules  530  and  550 . The display panel  110  may include a first short side, a second short side facing the first short side, and a long side vertical to the first short side or the second short side. For example, the first short side and the second short side may be in a widthwise direction of the display panel  110 , and the long side may be in a lengthwise direction of the display panel  110 . The widthwise direction and the lengthwise direction may be interchangeable. The display panel  110  may be divided into three regions with respect to a long-side direction X or the lengthwise direction of the display panel  110  and may be divided into three regions with respect to a short-side direction Y or the widthwise direction of the display panel  110 . For example, the long side of the display panel  110  may be divided into three equal portions with respect to a first lengthwise direction a 1  and a second lengthwise direction a 2 . The short side of the display panel  110  may be divided into three equal portions with respect to a first widthwise direction b 1  and a second widthwise direction b 2 . The display panel  110  may include four divided surfaces. For example, a left upper region where the first lengthwise direction a 1  meets the first widthwise direction b 1  may be a first four-divided surface (1). For example, a second four-divided surface (2) may be a right upper region where the second lengthwise direction a 2  meets the first widthwise direction b 1 . For example, a third four-divided surface (3) may be a right lower region where the second lengthwise direction a 2  meets the second widthwise direction b 2 . For example, a fourth four-divided surface (4) may be a left lower region where the first lengthwise direction a 1  meets the second widthwise direction b 2 . 
     For example, the first sound generating modules  430  and  450  may not be disposed at a center portion of the rear surface of the display panel  110  and may be disposed on the second four-divided surface (2) which is the right upper region where the second lengthwise direction a 2  meets the first widthwise direction b 1 . For example, the first sound generating modules  430  and  450  may be in a region where the second lengthwise direction a 2  meets the first widthwise direction b 1 . For example, the first sound generating modules  430  and  450  may be disposed in a region which is divided in the first widthwise direction b 1  and the second lengthwise direction a 2 . For example, the first sound generating modules  430  and  450  may be in a one-third region of the display panel  110  in the widthwise direction and a one-third region of the display panel  110  in the lengthwise direction. In  FIG.  15 A , the first sound generating modules  430  and  450  are illustrated as being disposed at specific positions of the second four-divided surface (2), but may be disposed at arbitrary positions of the second four-divided surface (2). For example, the first sound generating modules  430  and  450  may be on the second four-divided surface (2). For example, the second sound generating modules  530  and  550  may not be disposed at the center portion of the rear surface of the display panel  110  and may be on the fourth four-divided surface (4) which is the left lower region where the first lengthwise direction a 1  meets the second widthwise direction b 2 . For example, the second sound generating modules  530  and  550  may be in a region where the first lengthwise direction a 1  meets the second widthwise direction b 2 . For example, the second sound generating modules  530  and  550  may be in a region which is divided in the first lengthwise direction a 1  and the second widthwise direction b 2 . For example, the second sound generating modules  530  and  550  may be disposed in a one-third region of the display panel  110  in the widthwise direction and a one-third region of the display panel  110  in the lengthwise direction. In  FIG.  15 A , the second sound generating modules  530  and  550  are illustrated as being disposed at specific positions of the fourth four-divided surface (4), or may be disposed at arbitrary positions of the fourth four-divided surface (4). For example, the second sound generating modules  530  and  550  may be in the fourth four-divided surface (4). The first sound generating modules  430  and  450  and the second sound generating modules  530  and  550  may be disposed to be symmetrical with respect to a diagonal line of the display panel  110 . When sound generating modules are disposed in this manner, the sound generating modules may be disposed regardless of a size of a display panel. For example, sound generating modules may be easily disposed in a display apparatus, including a display panel having a small size like small electronic apparatuses, or a display apparatus including a display panel having a large size like televisions (TVs). Accordingly, a stereo sound may be enhanced, and a sound generating module may be applied to a speaker. 
     For example, a center of each of first vibration generating devices  431  and  451  of the first sound generating modules  430  and  450  may be spaced apart from a center region of the display module  100 . For example, a center of each of second vibration generating devices  431  and  451  of the second sound generating modules  530  and  550  may be spaced apart from a center region of the display module  100 . For example, a distance d 1  between the center of each of the first vibration generating devices  431  and  451  and the first short side of the display panel  110  may be ¼ to ⅓ of the long side of the display panel  110 . For example, a distance d 2  between the center of each of the second vibration generating devices  531  and  551  and the second short side of the display panel  110  may be ¼ to ⅓ of the long side of the display panel  110 . 
     With reference to  FIG.  15 B , a display apparatus  80  according to an embodiment of the present disclosure may further include a partition  900 . The partition  900  may be disposed at a rear center portion CL 1  of a display module  100 . For example, the partition  900  may be between first sound generating modules  430  and  450  and second sound generating modules  530  and  550 . For example, the partition  900  may spatially separate or divide a first rear region A 1  overlapping the first sound generating modules  430  and  450  and a second rear region A 2  overlapping the second sound generating modules  530  and  550  at the rear surface of the display panel  100 , thereby reducing or preventing interference between sounds generated by the first rear region A 1  and the second rear region A 2 . The partition  900  may spatially separate or divide the first rear region A 1  and the second rear region A 2  each provided in a rear surface of the display module  100  (or the display panel  100 ) to reduce or prevent interference between the sounds generated by the first rear region A 1  and the second rear region A 2 . Accordingly, the partition  900  may separate sounds generated by first vibration generating devices  431  and  451  and second vibration generating devices  531  and  551  to reduce or prevent interference between the generated sounds, thereby allowing a 2.0-channel sound to be output to a forward region with respect to the display module  100  based on a vibration of the display module  100 . Also, a sound generating module for enhancing a stereo sound may be provided. 
       FIGS.  16 A and  16 B  are rear views of a display panel according to another embodiment of the present disclosure. 
     With reference to  FIG.  16 A , a display apparatus  120  according to an embodiment of the present disclosure may include a plurality of first sound generating modules  430  and  450  and a plurality of second sound generating modules  530  and  550 . The display panel  110  may include a first short side, a second short side facing the first short side, and a long side vertical to the first short side or the second short side. For example, the first short side and the second short side may be in a widthwise direction of the display panel  110 , and the long side may be in a lengthwise direction of the display panel  110 . The widthwise direction and the lengthwise direction may be interchangeable. The display panel  110  may be divided into three regions with respect to a long-side direction X or the lengthwise direction of the display panel  110  and may be divided into three regions with respect to a short-side direction Y or the widthwise direction of the display panel  110 . For example, the long side of the display panel  110  may be divided into three equal portions with respect to a first lengthwise direction a 1  and a second lengthwise direction a 2 . The short side of the display panel  110  may be divided into three equal portions with respect to a first widthwise direction b 1  and a second widthwise direction b 2 . The display panel  110  may include four divided surfaces. For example, a left upper region where the first lengthwise direction a 1  meets the first widthwise direction b 1  may be a first four-divided surface (1). For example, a second four-divided surface (2) may be a right upper region where the second lengthwise direction a 2  meets the first widthwise direction b 1 . For example, a third four-divided surface (3) may be a right lower region where the second lengthwise direction a 2  meets the second widthwise direction b 2 . For example, a fourth four-divided surface (4) may be a left lower region where the first lengthwise direction a 1  meets the second widthwise direction b 2 . 
     For example, the first sound generating modules  430  and  450  may not be disposed at a center portion of the rear surface of the display panel  110  and may be disposed on the first four-divided surface (1) which is the left upper region where the first lengthwise direction a 1  meets the first widthwise direction b 1 . For example, the first sound generating modules  430  and  450  may be disposed in a region where the first lengthwise direction a 1  meets the first widthwise direction b 1 . For example, the first sound generating modules  430  and  450  may be disposed in a region which is divided in the first widthwise direction b 1  and the first lengthwise direction a 1 . For example, the first sound generating modules  430  and  450  may be in a one-third region of the display panel  110  in the widthwise direction and a one-third region of the display panel  110  in the lengthwise direction. In  FIG.  16 A , the first sound generating modules  430  and  450  are illustrated as being disposed at specific positions of the first four-divided surface (1), or may be disposed at arbitrary positions of the first four-divided surface (1). For example, the first sound generating modules  430  and  450  may be disposed on the first four-divided surface (1). For example, the second sound generating modules  530  and  550  may not be disposed at the center portion of the rear surface of the display panel  110  and may be disposed on the third four-divided surface (3) which is the right lower region where the second lengthwise direction a 2  meets the second widthwise direction b 2 . For example, the second sound generating modules  530  and  550  may be in a region where the second lengthwise direction a 2  meets the second widthwise direction b 2 . For example, the second sound generating modules  530  and  550  may be disposed in a region which is divided in the second lengthwise direction a 2  and the second widthwise direction b 2 . For example, the second sound generating modules  530  and  550  may be disposed in a one-third region of the display panel  110  in the widthwise direction and a one-third region of the display panel  110  in the lengthwise direction. In  FIG.  16 A , the second sound generating modules  530  and  550  are illustrated as being disposed at specific positions of the third four-divided surface (3), or may be disposed at arbitrary positions of the third four-divided surface (3). For example, the second sound generating modules  530  and  550  may be disposed in the third four-divided surface (3). The first sound generating modules  430  and  450  and the second sound generating modules  530  and  550  may be disposed to be symmetrical with respect to a diagonal line of the display panel  110 . When sound generating modules are disposed in this manner, the sound generating modules may be disposed regardless of a size of a display panel. For example, sound generating modules may be easily disposed in a display apparatus, including a display panel having a small size like small electronic apparatuses, or a display apparatus including a display panel having a large size like televisions (TVs). Accordingly, a stereo sound may be enhanced, and a sound generating module may be applied to a speaker. 
     For example, a center of each of first vibration generating devices  431  and  451  of the first sound generating modules  430  and  450  may be spaced apart from a center region of the display module  100 . For example, a center of each of second vibration generating devices  431  and  451  of the second sound generating modules  530  and  550  may be spaced apart from a center region of the display module  100 . For example, a distance d 1  between the center of each of the first vibration generating devices  431  and  451  and the first short side of the display panel  110  may be ¼ to ⅓ of the long side of the display panel  110 . For example, a distance d 2  between the center of each of the second vibration generating devices  531  and  551  and the second short side of the display panel  110  may be ¼ to ⅓ of the long side of the display panel  110 . 
     With reference to  FIG.  16 B , a display apparatus  130  according to an embodiment of the present disclosure may further include a partition  900 . The partition  900  may be disposed at a rear center portion CL 1  of a display module  100 . For example, the partition  900  may be between first sound generating modules  430  and  450  and second sound generating modules  530  and  550 . For example, the partition  900  may spatially separate or divide a first rear region A 1  overlapping the first sound generating modules  430  and  450  and a second rear region A 2  overlapping the second sound generating modules  530  and  550  at the rear surface of the display panel  100 , thereby reducing or preventing interference between sounds generated by the first rear region A 1  and the second rear region A 2 . The partition  900  may spatially separate or divide the first rear region A 1  and the second rear region A 2  each provided in a rear surface of the display module  100  (or the display panel  100 ) to prevent interference between the sounds generated by the first rear region A 1  and the second rear region A 2 . Accordingly, the partition  900  may separate sounds generated by first vibration generating devices  431  and  451  and second vibration generating devices  531  and  551  to reduce or prevent interference between the generated sounds, thereby allowing a 2.0-channel sound to be output to a forward region with respect to the display module  100  based on a vibration of the display module  100 . Also, a sound generating module for enhancing a stereo sound may be provided. 
       FIG.  17    illustrates a sound output characteristic of a sound generating module according to an embodiment of the present disclosure. 
     In  FIG.  17   , a dotted line represents a sound output characteristic of a sound generating module which includes a vibration generating device where a widthwise-direction length is longer than a lengthwise-direction length and is disposed at a center of the rear surface of the display panel of  FIG.  13   . A one-dot-dashed line represents a sound output characteristic of a sound generating module which includes a vibration generating device where a widthwise-direction length is equal to a lengthwise-direction length and is disposed at the center of the rear surface of the display panel of  FIG.  13   . A two-dot-dashed line represents a sound output characteristic of the sound generating module of  FIG.  13    including a vibration generating device where a widthwise-direction length is equal to a lengthwise-direction length. A solid line represents a sound output characteristic of the sound generating module of  FIG.  15 A  including a vibration generating device where a widthwise-direction length is equal to a lengthwise-direction length. In  FIG.  17   , the abscissa axis (x-axis) represents a frequency in hertz (Hz), and the ordinate axis (y-axis) represents a sound pressure level (SPL) in decibel (dB). 
     The sound output characteristic may be measured by a sound analysis apparatus. The sound analysis apparatus may include a sound card which transmits or receives a sound to or from a control personal computer (PC), an amplifier which amplifies a signal generated from the sound card and transfers the amplified signal to the sound generating module, and a microphone which collects a sound generated by the sound generating module in a display panel. The sound collected through the microphone may be input to the control PC through the sound card, and a control program may check the input sound to analyze the sounds of the sound generating module. 
     A sound output characteristic has been measured in an anechoic chamber which is closed in all directions, and measurement equipment has used Audio Precision company&#39;s APX525. Measurement has been performed under a condition where a driving voltage is 30 Vpp and a sound pressure level measurement distance to a center of a sound generating module is about 5 cm. An applied frequency signal has been applied as a sine sweep within a range of 20 Hz to 20 kHz, and ⅓ octave smoothing has been performed on a measurement result. A measurement method is not limited thereto. 
     With reference to  FIG.  17   , in comparison with a case (represented by a dotted line) including a sound generating device where a widthwise-direction length is longer than a lengthwise-direction length, it may be seen that, in a case (represented by a one-dot-dashed line) including a sound generating device where a widthwise-direction length is equal to a lengthwise-direction length, a sound pressure level is enhanced in about 200 Hz or less corresponding to the low sound band. Therefore, as described above with reference to  FIG.  5   , it may be seen that a sound generating module, including a sound generating device where a widthwise-direction length is equal to a lengthwise-direction length, enhances a sound pressure level. 
     For example, in comparison with a sound generating module (represented by a one-dot-dashed line) disposed at a center of a rear surface of a display panel, it may be seen that, in a sound generating module (represented by a two-dot-dashed line) disposed in an upper portion of a rear surface of a display panel, a sound pressure level is enhanced in about 800 Hz corresponding to the middle-pitched sound band and about 1 kHz or more corresponding to the high-pitched sound band. Accordingly, when a sound generating module is disposed in an upper portion of a rear surface of a display panel, it may be seen that a sound pressure level is enhanced. 
     For example, in comparison with a sound generating module (represented by a two-dot-dashed line) disposed at a center of a rear surface of a display panel, it may be seen that, in a sound generating module (represented by a solid line) disposed in an upper portion of a rear surface of a display panel and disposed in a diagonal direction, a sound pressure level is enhanced in about 200 Hz or less corresponding to the low-pitched sound band. Also, it may be seen that a sound pressure level is enhanced in about 800 Hz corresponding to the middle-pitched sound band and about 1 kHz or more corresponding to the high-pitched sound band. Accordingly, when a sound generating module is disposed in an upper portion of a rear surface of a display panel and disposed in a diagonal direction, it may be seen that a sound pressure level is enhanced in the low-pitched sound band and the high-pitched sound band. Also, when the sound generating module represented by the solid line is applied to a speaker of an electronic apparatus or the like, it may be seen that a frequency response is flat compared to other sound generating modules. For example, it may be seen that the sound generating module represented by the solid line has a flat sound pressure characteristic in a total frequency domain, thereby providing a display apparatus including a speaker having a flat sound pressure level in the total frequency domain. 
       FIGS.  18 A and  18 B  illustrate a sound output characteristic of a sound generating module according to an embodiment of the present disclosure. 
       FIGS.  18 A to  20 B  show results obtained through measurement performed for testing a stereo sound or a sound separation sensitivity of left and right sound generating modules. In  FIGS.  18 A and  18 B , a sound output characteristic of a sound generating module represented by the one-dot-dashed line of  FIG.  17    is shown. A one-dot-dashed line shows a sound output characteristic of the left sound generating module, and a one-dot-dashed thick line shows a sound output characteristic of the right sound generating module.  FIG.  18 A  shows an example where a signal is applied to a first sound generating module, and  FIG.  18 B  shows an example where a signal is applied to a second sound generating module. In  FIGS.  18 A and  18 B , the abscissa axis (x-axis) represents a frequency in hertz (Hz), and the ordinate axis (y-axis) represents a sound pressure level (SPL) in decibel (dB). A method of measuring a sound output characteristic is the same as description given above with reference to  FIG.  17   , and thus, its detailed description is omitted. 
     With reference to  FIGS.  18 A and  18 B , it may be seen that the sound output characteristic of the right sound generating module and the sound output characteristic of the left sound generating module are symmetrically shown. However, it may be seen that a sound pressure level is reduced in a frequency of about 2.5 kHz or more. 
       FIGS.  19 A and  19 B  illustrate a sound output characteristic of a sound generating module according to an embodiment of the present disclosure. 
     In  FIGS.  19 A and  19 B , a sound output characteristic of a sound generating module represented by the two-dot-dashed line of  FIG.  17    is shown. A two-dot-dashed line shows a sound output characteristic of a left sound generating module, and a two-dot-dashed thick line shows a sound output characteristic of a right sound generating module.  FIG.  19 A  shows an example where a signal is applied to a first sound generating module, and  FIG.  19 B  shows an example where a signal is applied to a second sound generating module. In  FIGS.  19 A and  19 B , the abscissa axis (x-axis) represents a frequency in hertz (Hz), and the ordinate axis (y-axis) represents a sound pressure level (SPL) in decibel (dB). A method of measuring a sound output characteristic is the same as description given above with reference to  FIG.  17   , and thus, its detailed description is omitted. 
     With reference to  FIGS.  19 A and  19 B , it may be seen that the sound output characteristic of the right sound generating module and the sound output characteristic of the left sound generating module are symmetrically shown. However, it may be seen that a sound pressure level does not increase in a frequency of about 1 kHz or more. 
       FIGS.  20 A and  20 B  illustrate a sound output characteristic of a sound generating module according to an embodiment of the present disclosure. 
     In  FIGS.  20 A and  20 B , a sound output characteristic of a sound generating module represented by the solid line of  FIG.  17    is shown. A two-dot-dashed line shows a sound output characteristic of a left sound generating module, and a two-dot-dashed thick line shows a sound output characteristic of a right sound generating module.  FIG.  20 A  shows an example where a signal is applied to a first sound generating module, and  FIG.  20 B  shows an example where a signal is applied to a second sound generating module. In  FIGS.  20 A and  20 B , the abscissa axis (x-axis) represents a frequency in hertz (Hz), and the ordinate axis (y-axis) represents a sound pressure level (SPL) in decibel (dB). A method of measuring a sound output characteristic is the same as description given above with reference to  FIG.  17   , and thus, its detailed description is omitted. 
     With reference to  FIGS.  20 A and  20 B , it may be seen that the sound output characteristic of the right sound generating module and the sound output characteristic of the left sound generating module are symmetrically shown. Therefore, a left sound and a right sound may be separated from each other, and thus, a stereo sound may be enhanced. In  FIGS.  18 A and  18 B , it may be seen that a sound pressure level is reduced in a frequency of about 2.5 kHz or more. In comparison with this, it may be seen that, in a sound generating module according to an embodiment of the present disclosure, a sound pressure level is enhanced in a frequency of about 2.5 kHz or more. In  FIGS.  19 A and  19 B , it may be seen that a sound pressure level does not increase in a frequency of about 1 kHz or more. In comparison with this, it may be seen that, in the sound generating module according to an embodiment of the present disclosure, a sound pressure level is enhanced in a frequency of about 1 kHz or more. Accordingly, in the sound generating module according to an embodiment of the present disclosure, it may be seen that a stereo sound is enhanced, and moreover, a sound pressure level is enhanced in a frequency of the middle-high-pitched sound band. 
     A sound generating module according to an embodiment of the present disclosure may be applied as a sound generating module in a display apparatus. The display apparatus according to an embodiment of the present disclosure may be applied to mobile apparatuses, video phones, smart watches, watch phones, wearable apparatuses, foldable apparatuses, rollable apparatuses, bendable apparatuses, flexible apparatuses, curved apparatuses, portable multimedia players (PMPs), personal digital assistants (PDAs), electronic organizers, desktop personal computers (PCs), laptop PCs, netbook computers, workstations, navigation apparatuses, automotive navigation apparatuses, automotive display apparatuses, TVs, wall paper display apparatuses, signage apparatuses, game machines, notebook computers, monitors, cameras, camcorders, home appliances, etc. Also, the sound generating device according to an embodiment of the present disclosure may be applied to organic light emitting lighting apparatuses or inorganic light emitting lighting apparatuses. When the sound generating module is applied to a lighting apparatus, the sound generating module may act as lighting and a speaker. The sound generating module according to an embodiment of the present disclosure may be applied to a receiver and/or a speaker such as an electronic apparatus. 
     A display apparatus according to an embodiment of the present disclosure will be described below. 
     According to an embodiment of the present disclosure, a display apparatus include a display module including a display panel configured to display an image and a sound generating module on a rear surface of the display panel, wherein the sound generating module includes a vibration generating device, a circuit board on a lower surface of the vibration generating device, a first adhesive member between the circuit board and the vibration generating device, and a second adhesive member between the vibration generating device and the display panel, an elastic modulus of the second adhesive member differing from an elastic modulus of the first adhesive member. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the elastic modulus of the first adhesive member may be greater than the elastic modulus of the second adhesive member. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the first adhesive member may include a material having conductivity. 
     For example, in a display apparatus according to an embodiment of the present disclosure, a size of the circuit board may be the same as a size of the vibration generating device. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the circuit board may include a base film on the lower surface of the vibration generating device, a first electrode and a second electrode respectively on an upper surface and a lower surface of the base film, and a passivation layer on each of the upper surface and the lower surface of the base film. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the base film may include a flexible printed circuit board including a polyimide. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the display panel may include a first short side, a second short side facing the first short side, and a long side vertical to the first short side or the second short side, and a distance between a center of the vibration generating device and the first short side of the display panel may be ¼ to ⅓ of the long side of the display panel. 
     For example, a display apparatus according to an embodiment of the present disclosure may further include a second sound generating module on the rear surface of the display panel, the second sound generating module including a second vibration generating device. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the display panel may include a first short side, a second short side facing the first short side, and a long side vertical to the first short side or the second short side, and a distance between a center of the vibration generating device and the second short side of the display panel may be ¼ to ⅓ of the long side of the display panel. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the sound generating module may be symmetrical with the second sound generating module with respect to a center portion of the display module. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the display panel may include a first short side, a second short side facing the first short side, a long side vertical to the first short side or the second short side, a first lengthwise direction and a second lengthwise direction dividing the first short side or the second short side into three equal portions, and a first widthwise direction and a second widthwise direction dividing the long side into three equal portions, the sound generating module may be in a region divided in the second lengthwise direction and the first widthwise direction or in a region divided in the first lengthwise direction and the first widthwise direction, and the second sound generating module may be in a region divided in the first lengthwise direction and the second widthwise direction or in a region divided in the second lengthwise direction and the second widthwise direction. 
     For example, in a display apparatus according to an embodiment of the present disclosure, each of the vibration generating device and the second vibration generating device may include a piezoelectric material layer. 
     For example, in a display apparatus according to an embodiment of the present disclosure may further include a partition disposed at a center portion of the rear surface of the display module. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the display module may include a first rear region overlapping the sound generating module and a second rear region overlapping the second sound generating module, and the partition may be between the first rear region and the second rear region. 
     According to an embodiment of the present disclosure, a display apparatus includes a display module including a display panel configured to display an image and a sound generating module on a rear surface of the display panel, wherein the sound generating module includes a vibration generating device, a circuit board on a lower surface of the vibration generating device, a first adhesive member and a third adhesive member between the circuit board and the vibration generating device, and a member between the first adhesive member and the third adhesive member. 
     For example, in a display apparatus according to an embodiment of the present disclosure, a material of the first adhesive member may differ from a material of the third adhesive member. 
     For example, a display apparatus according to an embodiment of the present disclosure may further include at least one electrode on the lower surface of the vibration generating device, wherein the third adhesive member may be on the at least one electrode. 
     For example, in a display apparatus according to an embodiment of the present disclosure may further include a second adhesive member between the vibration generating device and the display panel. 
     For example, in a display apparatus according to an embodiment of the present disclosure, an elastic modulus of the second adhesive member may differ from an elastic modulus of the first adhesive member. 
     For example, in a display apparatus according to an embodiment of the present disclosure, a size of the circuit board may be the same as a size of the vibration generating device. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the circuit board may include a base film on the lower surface of the vibration generating device, a first electrode and a second electrode respectively on an upper surface and a lower surface of the base film, and a passivation layer on each of the upper surface and the lower surface of the base film. 
     For example, in a display apparatus according to an embodiment of the present disclosure, each of the first electrode and the second electrode may be attached to the lower surface of the vibration generating device by the third adhesive member. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the first adhesive member may be d between the passivation layer on the upper surface of the base film and the vibration generating device. 
     For example, a display apparatus according to an embodiment of the present disclosure may further include a fourth adhesive member disposed between the circuit board and the member. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the display panel may include a first short side, a second short side facing the first short side, and a long side vertical to the first short side or the second short side, and a distance between a center of the vibration generating device and the first short side of the display panel may be ¼ to ⅓ of the long side of the display panel. 
     For example, a display apparatus according to an embodiment of the present disclosure may further include a second sound generating module on the rear surface of the display panel, the second sound generating module including a second vibration generating device. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the display panel may include a first short side, a second short side facing the first short side, and a long side vertical to the first short side or the second short side, and a distance between a center of the vibration generating device and the second short side of the display panel may be ¼ to ⅓ of the long side of the display panel. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the sound generating module may be symmetrical with the second sound generating module with respect to a center portion of the display module. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the display panel may include a first short side, a second short side facing the first short side, a long side vertical to the first short side or the second short side, a first lengthwise direction and a second lengthwise direction dividing the first short side or the second short side into three equal portions, and a first widthwise direction and a second widthwise direction dividing the long side into three equal portions, the sound generating module may be in a region divided in the second lengthwise direction and the first widthwise direction or in a region divided in the first lengthwise direction and the first widthwise direction, and the second sound generating module may be in a region divided in the first lengthwise direction and the second widthwise direction or in a region divided in the second lengthwise direction and the second widthwise direction. 
     For example, a display apparatus according to an embodiment of the present disclosure may further include a partition disposed at a center portion of the rear surface of the display module. 
     For example, in a display apparatus according to an embodiment of the present disclosure, the display module may include a first rear region overlapping the sound generating module and a second rear region overlapping the second sound generating module, and the partition may be between the first rear region and the second rear region. 
     As described above, the display apparatus according to embodiments of the present disclosure may include the sound generating device which vibrates the display panel to generate a sound, and thus, may output the sound to a forward region in front of the display panel. Accordingly, an immersion experience of a viewer watching an image displayed by the display apparatus may be enhanced. 
     Moreover, since the display apparatus according to embodiments of the present disclosure includes the sound generating module including adhesive members having different elastic modulus, the durability of the sound generating module against a vibration or an external impact may be enhanced, and the durability of the sound generating module against attachment/detachment may be enhanced. 
     Moreover, since the display apparatus according to embodiments of the present disclosure includes the sound generating module including an adhesive member and a member which have different elastic modulus, the durability of the sound generating module against a vibration or an external impact may be enhanced, the durability of the sound generating module against attachment/detachment may be enhanced, and an adhesive surface between a circuit board and an adhesive member may be uniform, thereby reducing or preventing the defect of the circuit board. 
     It will be apparent to those skilled in the art that various modifications and variations may be made in the display apparatus of present disclosure without departing from the technical idea or scope of the disclosures. Thus, it is intended that embodiments of the present disclosure cover the modifications and variations of the disclosure provided they come within the scope of the appended claims and their equivalents.