Patent Description:
In general, the display apparatus is used as a screen to display visual information such as a television, a monitor, a laptop computer, a smart phone, a tablet computer, an electronic pad wearable device, a watch phone, a portable information device, a navigation systemor an electronc products, a vehicle control display device or the home appliances.

A general display apparatus may include a display panel for representing a video image, and an audio device for providing sounds related to the video image. However, the conventional display apparatus has a limitation in which sound quality deteriorates due to inferference between sounds reflected from a wall or the floor because the sounds output from the sound device proceed to the rear or bottom side of the display panel. Therefore, it is difficult to accurately provide the sound to the viewers, so that the immersion of viewers may be deteriorated.

<CIT> relates to a display apparatus which includes a display panel configured to display an image by emitting light, a rear structure configured to support the display panel, a vibration generator configured to vibrate the display panel, and a supporting member between the display panel and the vibration generator, the supporting member being configured to maintain a distance between the display panel and the vibration generator.

<CIT> relates to a display device which includes a display panel which displays an image; a rear chassis which covers a rear surface of the display panel, where the rear chassis includes: a first protruding region which protrudes to a rear surface of the chassis; and a second protruding region which is disposed in the first protruding region and further protrudes from the first protruding region to the rear surface of the chassis; and an acoustic element disposed in the first protruding region and at a space defined in the second protruding region, where the acoustic element includes a plurality of electrodes, and a vibration material layer disposed between the electrodes.

<CIT> relates to an exciting device capable of producing sound by a sound-producing vibration body of a main body of an apparatus.

<CIT> reltates to a television receiver cabinet that is including a plurality of wall members and at least one speaker horn sub-assembly, wherein at least one speaker unit is contained to form a horn structure. The loudspeaker horn sub-assembly utilizes at least a part of the wall members, in its original place, as a component for structuring the sub-assembly.

<CIT> relates to a liquid crystal display device including a liquid crystal, a front surface cover, and a rear surface cover, wherein a sounding body module is obtained by integrating the liquid crystal display device with the piezoelectric sounding body and is installed inside the housing of an electronic apparatus.

<CIT> relates to an electro-optical device with a sound generator including a sound generator.

The inventors of the present disclosure recognized problems with a related display apparatus and conducted various experiments to improve the sound quality and to provide the sound to the front direction of the display panel when viewers see an image in front of the display panel. After a number of experiments, the inventors can provide a display apparatus having a new structure capable of generating sounds that can proceed in front of the display panel and improving the sound quality.

One purpose of the present disclosure is to provide a display apparatus accurately generating sounds. Another purpose of the present disclosure is to provide a display apparatus generating sounds proceeding to the front direction of the display panel.

Still another purpose of the present disclosure is to provide a display apparatus improving the sound quality and increasing viewer immersion. Especially, the present disclosure provides a display apparatus maintaining an ultra-thin structure by mounting a sound generating device on the back side of the display panel inside of the rear cover.

In addition to the technical purposes of the present disclosure mentioned above, other features and advantages of the present disclosure are described below. From such descriptions, the technical purposes and advantages will be clearly understood by those skilled persons in the art.

These objects are solved by the subject-matter of the independent claim. Further advantageous embodiments and refinements are described in the respective dependent claims.

Within this disclosure, a front surface of the display apparatus may be defined as the surface of the display apparatus from which light is emitted and/or from which images are shown to a viewer of the display apparatus. The rear surface of the display apparatus may be defined as the surface opposite to the front surface. A front direction may be defined as a direction or a vector perpendicular to the front surface and/or pointing away from the front surface. A thickness direction of the display apparatus may be defined as a direction in parallel to the front direction. A horizontal direction may be defined as a direction perpendicular to the front direction. A front or front side of the display apparatus may be a side of the display apparatus arranged at the front surface of the display apparatus. A rear or rear side of the display apparatus may be a side of the display apparatus arranged at the rear surface of the display apparatus.

Correspondingly, a rear surface, a rear side, or a rear and a front surface, a front side or a front of elements of the display apparatus may be defined in accordance with the aforedefined rear direction and front direction, respectively.

A thickness depth or a length of an element may be measured along the front direction or the thickness direction, and a width of an element may be measured along the horizontal direction. Also, within the context of the present invention, "upper" may refer to "front" and "loower" may be refer to "rear".

The first vibration unit may include: a first metal substrate attached at the first stepped portion; and a first piezo vibrator or an electrical active material attached at a rear surface of the first metal substrate. The first metal substrate may be attached to the first stepped portion by an adhesive. The piezo vibrator may also be denoted as piezo element.

The first vibration unit may further include a second metal substrate attached at a rear surface of the first piezo vibrator or the electrical active material.

The first vibration unit may include a piezo vibrator or an electrical active material attached at the first stepped portion; and a metal substrate attached at a rear surface of the piezo vibrator. The piezo vibrator or the electrical active material may be attached to the first stepped portion by an adhesive.

The first depth may be greater than half of the thickness of the back cover.

The display apparatus comprises a front depression formed in the back cover from the front surface of the back cover with a third width and a third depth, and further comprises a second vibration unit disposed at a second stepped portion between the front depression and the through hole.

The second vibration unit may include a metal substrate attached at the second stepped portion; and a second piezo vibrator or an electrical active material attached at a front surface of the metal substrate.

The first piezo vibrator may have a surface area different from the surface area of the second piezo vibrator. Thus, a frequency band or frequency bandwith of sound or vibration generated by the first and second vibration units may be different.

The first vibration unit may have a frequency bandwidth different from the frequency bandwidth of the second vibration unit. Thus, one of the first vibration unit and the second vibration unit may implement a tweeter and the other one may implement a woofer.

The first depth and the third depth may be the same. A difference between the second depth and the third depth may be smaller than the third depth.

The display apparatus may further include an enclosure inserted into the rear depression and surrounding or covering a rear space of the first vibration unit.

The enclosure may be made from an elastic material.

The first vibration unit may be mounted inside the enclosure with the enclosure being arranged between the first vibration unit and the first stepped portion and having a front side open toward the through hole. The first vibration unit may be attached to the enclosure and the enclosure may be attached to the back cover.

The apparatus may further comprise an adhesive element configured to attach the front surface of the back cover to the display module.

The apparatus may further comprise a metal plate attached at a portion of the rear surface of the display module exposed by the front depression and/or the through hole.

The front depression, the rear depression and the through hole may each have a circular shape and/or may overlap each other and/or may be eccentrically arranged.

The first metal substrate, the second metal substrate or the metal substrate may have a circular shape.

The first and second piezo vibrators may be arranged at a central or middle portion of the first metal substrate, the second metal substrate and the metal substrate, respectively.

Any one of the first vibration unit and the second vibration unit may generate sound or vibrations corresponding to a frequency bandwidth of <NUM> to <NUM>. The other one may generate sound or vibrations corresponding to a frequency bandwidth of <NUM> to <NUM>,<NUM>.

The display module may include a display panel, a functional film and a heat diffusion element. The display panel may be implemented as an LCD display panel or an OLED display panel or any other suitable type of display panel. The display module and/or the display panel may be flexible.

Another display apparatus according to the present disclosure comprises: a display module; a back cover disposed at a rear surface of the display module; a depression recessed into the back cover from a first surface of the back cover with a first width and a first depth; a penetration through from a second surface of the back cover to the depression with a second width smaller than the first width and a second depth corresponding to a difference between a thickness of the back cover and the first depth; and a first piezo vibration unit disposed at a stepped portion between the penetration and the depression. The penetration may also be denoted as through-hole.

The display apparatus may further comprise: an adhesive element attaching the second surface of the back cover having the penetration to the display module.

The first piezo vibration unit may include: a metal substrate attached at the stepped portion. The first piezo vibration unit may further include a piezo element attached at a rear surface of the metal substrate. The piezo element may be denoted as piezo vibrator.

The first piezo vibration unit may include: a piezo element attached at the stepped portion. The first piezo vibration unit may further include a metal substrate attached at a rear surface of the piezo element.

The first depth of the depression may be smaller than a half of the thickness of the back cover.

The first depth of the depression may be larger than a half of the thickness of the back cover.

The display apparatus may further comprise: a heat radiating metal plate attached at portions of the rear surface of the display module exposed by the penetration.

The display apparatus may further comprise: an upper depression recessed into the back cover from the second surface of the back cover with a third width larger than the second width and a third depth less than the second depth.

The display apparatus further may further comprise: a second piezo vibration unit disposed at an upper stepped portion between the upper depression and the penetration.

The first piezo vibration unit may generate a sound vibration having different frequency bandwidth from the second piezo vibration unit.

In addition, a display apparatus according to the present disclosure comprises: a display module including display panel displaying video images; a back cover disposed at a rear surface of the display module; a first depression formed at a rear surface of the back cover; a through hole penetrating the back cover from first depression to an upper surface of the back cover; and a vibration generating module disposed inside the first depression for providing sound vibration to the back cover via the through hole.

The first depression may have a depth larger than the through hole.

The first depression may have a depth smaller than the through hole.

The vibration generating module may include: a piezo element. The vibration generating module may further include a metal substrate attached at one of an upper surface and a lower surface of the piezo element.

The display apparatus may further comprise: a heat radiating metal plate attached at a portion of the rear surface of the display module exposed by the through hole.

In one embodiment, the first depression may include: a first width; and a first depth smaller than a thickness of the back cover. The through hole may include: a second width smaller than the first width. The through hole may further include a second depth corresponding to difference between the thickness of the back cover and the first depth.

In one embodiment, the display apparatus may further comprise: a second depression formed at an upper surface of the back cover with a third width larger than the second width and a third depth smaller than the second depth. The through hole may have a thickness corresponding to difference between the second depth and the third depth.

In one embodiment, the vibration generating module may include: a first piezo vibration unit disposed inside the first depression. The vibration generating module mayfurther include a second piezo vibration unit disposed inside the second depression.

In one embodiment, the first piezo vibration unit may generate sound vibrations having frequency bandwidth different from the second piezo vibration unit.

In one embodiment, the vibration generating module may include: a piezo element. The vibration generating module may further include an enclosure surrounding a rear space of the piezo element.

Any one of the first piezo vibration unit and the second vibration unit may generate sound vibrations corresponding to a frequency bandwidth of <NUM> to <NUM>. The other one may generate sound vibrations corresponding to a frequency bandwidth of <NUM> to <NUM>,<NUM>.

According to an example of the present disclosure, it is possible to provide a display apparatus accuartely generating and transmitting the sounds, improving the sound quality, and increasing immersion of viewers. According to another example of the present disclosure, it is possible to provide a display apparatus generating sounds to the front of the display panel. In particular, with a structure in which a sound generating device providing sound vibration to a display panel is embedded inside of the rear cover, it is possible to provide a display apparatus with a built-in sound generating device having an ultra-thin structure. Further, by stacking and embedding sound generating devices of various frequency bands inside of the rear cover, it is possible to provide an ultra-thin display apparatus generating sounds of various bands.

In addition to the effects of the present disclosure mentioned above, other features and advantages of the present disclosure may be described below, or may be clearly understood by those skilled persons in this art from such below descriptions and explanations.

The sixth, seventh and eighth embodiments shown in <FIG> fall under the scope defined by the claims. The remaining embodiments do not fall under the scope of the claims but are useful for understanding.

Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. In the specification, it should be noted that like reference numerals already used to denote like elements in other drawings are used for elements wherever possible. In the following description, when a function and a configuration known to those skilled in the art are irrelevant to the essential configuration of the present disclosure, their detailed descriptions will be omitted. The terms described in the specification should be understood as follows. Advantages and features of the present disclosure, and implementation methods thereof will be clarified through following embodiments described with reference to the accompanying drawings.

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. 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 will be omitted.

In the case that "comprise," "have," and "include" described in the present specification are used, another part may also be present unless "only" is used. The terms in a singular form may include plural forms unless noted to the contrary.

In describing a positional relationship, for example, when the positional order is described as "on," "above," "below," and "next," the case of no contact there-between may be included, unless "just" or "direct" is used. If it is mentioned that a first element is positioned "on" a second element, it does not mean that the first element is essentially positioned above the second element in the figure. The upper part and the lower part of an object concerned may be changed depending on the orientation of the object. Consequently, the case in which a first element is positioned "on" a second element includes the case in which the first element is positioned "below" the second element as well as the case in which the first element is positioned "above" the second element in the figure or in an actual configuration.

In describing a temporal 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 "just" or "direct" is used.

It will be understood that, although the terms "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms.

In describing the elements of the present disclosure, terms such as the first, the second, A, B, (a) and (b) may be used. These terms are only to distinguish the elements from other elements, and the terns are not limited in nature, order, sequence or number of the elements. When an element is described as being "linked", "coupled" or "connected" to another element that element may be directly connected to or connected to that other element, but indirectly unless otherwise specificed. It is to be understood that other elements may be "interposed" between each element that may be connected to or coupled to.

It should be understood that the term "at least one" includes all combinations related with any one item. For example, "at least one among a first element, a second element and a third element" may include all combinations of two or more elements selected from the first, second and third elements as well as each element of the first, second and third elements.

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 a co-dependent relationship.

The 'display apparatus' in this application may comprise a liquid crystal module (LCM), an organic light emitting display module (OLED Module), or a quantum dot module (QD Module) which are have a display panel and a driver for driving the display panel. The `display apparatus' may further comprise a complete product or final product including LCM, OLED Module or QD Module such as a note-book computer, a television set, a computer monitor, an equipment apparatus having an automotive apparatus or other modules for vehicle, a set electronic apparatus or a set device (or set apparatus) such as a smart phone or a mobile electronic apparatus.

Therefore, the `display apparatus' may be any one of a display device such as LCM, OLED Module and QD Module, an application device including LCM, OLED Module or QD Module, or a set apparatus for end user's final devices.

In another example, the LCM, OLED Module or QD Module may be referred to the `display apparatus', and the final electronic devices including LCM, OLED Module or QD Module may be referred to the 'set apparatus'. For example, the display apparatus may include a display panel of liquid crystal display or organic electroluminescence display, and a source printed circuit board (PCB) for driving the display panel. The set apparatus may include the display apparatus and a set PCB or control PCB for driving the set apparatus itself by connecting to the display apparatus and the source PCB.

The display panel according to the embodiments of the present disclosure may include a liquid crystal display panel, an organic light emitting diode display panel, and an electroluminescent display panel, but it is not limited thereto. For example, display panel may have any structure in which the display panel may be vibrated to generate sound. In addition, the display panel applied to the display apparatus according to the embodiment of the present disclosure is not limited to the shape or size of the display panel.

In the case that 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 (or sub pixels) defined by the gate lines and the data lines. The display panel may include an array substrate including thin film transistor as a switching element for controlling the light transmittance of each pixel, an upper substrate including a color filter and/or a black matrix, and a liquid crystal layer disposed between the array substrate and the upper substrate.

In the case that the display panel is an organic light emitting diode display panel, the display panel may include a plurality of gate lines, a plurality of data lines, and a plurality of pixels (or sub pixels) defined by the gate lines and the data lines. The display panel may include an array substrate including thin film transistor for applying the electric voltage to each pixel selectively, an organic light emitting layer on the array substrate, and an encapsulation substrate disposed on the array substrate for covering the organic light emitting layer. The encapsulation substrate may protect the thin film transistor and the organic light emitting layer from any external shocks, and prevent moisture and oxygen from penetrating into the organic light emitting layer. In addition, the organic light emitting layer formed on the array substrate may be replaced by the inorganic light emitting layer, the quantum dot light emitting layer, or the micro light emitting diode element.

The display apparatus including the sound generating unit according to the present disclosure may be applied to the vehicle as the user interface module such as the central control panel in the automobile. For example, the display panel may be installed at the center fascia between the driver seat and the assistant seat so that the vibration of the display panel propagates toward the interior space of the vehicle. Therefore, the in-car audio can be improved compared to having conventional speakers only at inside sides of the car.

Hereinafter, an example of a display apparatus according to the present disclosure will be described in detail with reference to the accompanying drawings. In designating reference numerals to elements of each drawing, the same components may have the same reference numerals as much as possible even though they are shown in different drawings. Scale of the elements shown in the accompanying drawings have a different scale from the actual for convenience of description, it is not limited to the scale shown in the drawings.

<FIG> is a diagram illustrating a display apparatus having a sound generating unit at the rear side according to the present disclosure. Referring to <FIG>, the display apparatus according to the present disclosure may include a display module <NUM> and may output acoustics or sounds PVS in accordance with vibration of the display module <NUM> for representing image data. For example, in a display apparatus, the display module <NUM> may be vibrated by a sound generating unit <NUM> to output sounds PVS. Most of the sounds PVS generated by the vibration of the display module <NUM> may be directly output toward the front FD of the display apparatus and/or the display module <NUM>. The display apparatus according to the present disclosure can use the display module <NUM> as a diaphragm for generating sounds PVS and outputting the sounds PVS to the front FD of the display module <NUM>. Accordingly, the sounds can be accurately transmitted to the viewers and the sound quality can be improved, and the immersion of viewers can be enhanced. The display module <NUM> may be configured to display an image to a viewer.

In the display apparatus according to the present disclosure, the sound generating unit <NUM> provides a vibration, vibration forces or a sound pressure to the display module <NUM>, and the display module <NUM> thereby vibrates to make sound. The display module <NUM> may be formed of a substrate easily vibrated such as a large area glass substrate, and may include a back cover <NUM> and a guide panel <NUM> for supporting the display module <NUM> on a rear surface of the display apparatus. Installing the vibration generating unit <NUM> to the rear surface of the display module <NUM> by replacing speakers used in the related arts, the present disclosure may provide a structure for maintaining or reducing the thickness of the whole display apparatus including the display module <NUM>. Hereinafter, referring to figures, various embodiments of the present disclosure will be described in detail.

<FIG> is a cross-sectional view, cutting along I-I' in <FIG>, illustrating a structure of the display apparatus according to the first embodiment of the present disclosure. When it is necessary, it will be described with reference to <FIG> showing the overall structure of the display apparatus according to the present disclosure.

Referring to <FIG>, a display apparatus according to the first embodiment of the present disclosure may comprise a display module <NUM>, a back cover <NUM> and a sound generating unit <NUM>. The sound generation unit <NUM> may be implemented as a piezo vibration unit (or piezoelectric vibration unit) PZ suitable for mounting inside the back cover <NUM> which may be coupled to the rear surface of the display module <NUM>. For example, a piezo element (also denoted as piezo vibrator) or an electrical active material (EAM) may be used for the sound generating unit <NUM>.

The display module <NUM> may include a display panel <NUM>, a functional film <NUM> and a heat diffusion element <NUM>. The display panel <NUM> may be implemented as various types of the display. The display panel <NUM> may vibrate in response to the vibration of the sound generating unit <NUM> to generate sound and to directly output the sounds PVS to the front of the display panel <NUM> front direction FD. Thereby the display panel <NUM> may function as a speaker or a vibrating plate which is directly generating the sounds PVS. For example, when display module <NUM> plays a role for generating the sounds PVS, the display module <NUM> may be a diaphragm, a panel speaker or a flat speaker that directly generates the sounds PVS.

In one example, the display panel <NUM> may include a pixel circuit disposed on a substrate (or base substrate), and a pixel array layer (or display unit) connected to the pixel circuit and having an anode electrode, a cathode electrode and an organic emission layer. The display panel <NUM> may display an image in a top emission type, a bottom emission type or a dual emission type according to the structure of the pixel array layer. The anode electrode may be expressed as a first electrode or a pixel electrode, but it is not limited to this term. The cathode electrode may be expressed as a second electrode or a common electrode, but it is not limited to this term.

The functional film <NUM> may include an anti-reflection layer (or anti-reflective film) for preventing ambient light reflection and improving outdoor visibility and contrast ratio for an image displayed on the display panel <NUM>. For example, the anti-reflection layer may be a circular polarized layer (or circular polarization film) that prevents reflected light from being reflected by thin film transistors and/or lines disposed at the pixel array layer of the display panel <NUM> to the viewers. Although not shown in figures, the functional film <NUM> may be attached on the display panel <NUM> using a transparent adhesive layer.

In one example, the functional film <NUM> may futher include a light path control layer (or an optical film) that adjusts a path of light emitted from the pixel array layer of the display panel <NUM> toward viewers. The light path control layer may include a structure in which a high refractive layer and a low refractive layer are alternately stacked, thereby the path of light incident from the pixel array layer may be changed to minimize the color shift phenomena according to the viewing angle. In this case, the low refractive layer may be disposed at the topmost layer of the light path control layer.

In one example, the display module <NUM> may further include a touch electrode unit for user interface using a user's touch. The touch electrode unit may be inserted between the display panel <NUM> and the functional film <NUM> or embedded into the display panel <NUM> for the in-cell touch type. As an example of the in-cell touch type, the touch electrode unit may include the touch electrodes of the mutual capacitance type or the self-capacitance type.

The heat diffusion element <NUM> may have a thin sheet shape adhered to the whole rear surface of the display panel <NUM>. The heat diffusion element <NUM> may be disposed on the rear surface of the display module <NUM> so as to overlap with the sound generating unit <NUM>, thereby the heat generated when the sound generating unit <NUM> is operated may be diffused, e.g. toward the back cover <NUM> or the display module <NUM>. Accordingly the performance degradation of the sound generating unit <NUM> caused by the heat can be prevented. In addition, the heat diffusion element <NUM> may have a size corresponding to the whole rear surface of the display panel <NUM> to diffuse the heat generated, when the sound generating unit <NUM> is operated, to the wider areas. Accordningly, it is possible to prevent the heat from being intensively concentrated to a local area of the display panel <NUM> or the display module <NUM> overlapping with the sound generating unit <NUM>, thereby the local luminance non-uniformity of the display module <NUM> can be minimized or prevented.

For example, the heat diffusion element <NUM> may include a material having high thermal conductivity such as any one material of aluminum (Al), copper (Cu), silver (Ag) and magnesium (Mg) or an alloy of them, but it is not limited thereto.

The back cover <NUM> may be disposed on the rear surface of the display panel <NUM> or the display module <NUM>. The back cover <NUM> may be configured to mount or fix the sound generating unit <NUM> therein.

In one example, the back cover <NUM> may cover the rear surface of the display panel <NUM> or the display module <NUM>. The back cover <NUM> may be referred to as a supporting member, a housing, a system cover, a set cover, a rear cover, a cover bottom, a back frame, or chassis, but it is not limited thereto. The rear surface of the display module <NUM> may be referred to as one side, a first side, a back surface or a lower surface, but it is not limited thereto.

The back cover <NUM> may be attached to the rear surface of the display panel <NUM> or the display module <NUM> with an adhesive element <NUM>. The adhesive element <NUM> may include a pressure sensitive adhesive (PSA), an optical clear adhesive (OCA) or an optical clear resin (OCR), but it is not limited thereto. The back cover <NUM> may be attached to the whole rear surface of the display module <NUM>. The back cover <NUM> may function for protecting the rear surface of the display panel <NUM> or the display module <NUM> from any external shocks and for dissipating the heat generated from the display panel <NUM>, the sound generating unit <NUM> and/or the display module <NUM>.

In one example, the back cover <NUM> may have a plate shape covering the whole rear surface of the display module <NUM>, i.e., the entire rear surface of the heat diffusion element <NUM>. In some examples, the edge portions or the corner portions of the back cover <NUM> may have a sloped shape or a curved shape by chamfering or rounding process.

In one example, the back cover <NUM> may include a penetration S1 or a depression S2. The penetration S1 may be a through-hole penetrating the back cover <NUM> from the front surface to the rear surface. The depression S2 may have a well shape in which some thickness of the back cover <NUM> is removed to be sinked down from the rear surface. The depression S2 and the penetration S1 may be formed continuously as having a concentric circle, so that the back cover <NUM> may have a through-hole including the depression S2 and the penetration S1. In other words, the depression S2 and the penetration S1 may overlap. The depression S2 and/or the penetration S1 may each have a cylindrical shape.

The penetration S1 may have a smaller width than the depression S2. In this case, a step portion TH may be formed by or between the penetration S1 and the depression S2. Here, the penetration S1 and the depression S2 may have the same depth or any one may have larger depth than other. <FIG> shows the case in which the penetration S1 has the same depth as the depression S2.

A piezo vibration unit PZ may be installed inside of the penetration S1 and/or the depression S2. In detail, using an adhesive AH, the piezo vibration unit PZ may be fixed at the step portion TH. As shonw in <FIG>, the piezo vibration unit PZ may be mounted inside of the back cover <NUM>, so the whole thickness of the display apparatus is not increased to keep in thin condition as the original back cover thickness.

It is preferable that the sound generating unit <NUM> may be made of a thin film type element, such as a piezo vibration unit PZ for implementing the thin structure of the display apparatus. Between the piezo vibration unit PZ and the display module <NUM> or the display panel <NUM>, an empty space implemented by the penetration S1 may be disposed. The vibration generated from the piezo vibration unit PZ may vibrate the air filled within the space of penetration S1, and then a portion of the rear surface of the display panel <NUM> or the display panel <NUM> exposed by or corresponding to the penetration S1 may also vibrate. Accordingly, the display module <NUM> may generate sound PVS and the sounds PVS may be provided and transmitted to the front direction FD.

In one example, the display apparatus may include a sound generating unit <NUM> disposed at central portion (or middle area) of the display module <NUM>. In detail, one sound generating unit <NUM> may vibrate the rear central portion of the display module <NUM> to provide the sounds PVS from the vibration of the display module <NUM>.

In another example, the display apparatus may include a first sound generating unit <NUM> disposed at a first area (or a left area) and a second sound generating unit <NUM> disposed at a second area (or a right area), with respect to the central line of the rear surface of the dislay module <NUM>. In detail, the first sound generating unit <NUM> may vibrate the first rear area of the display module <NUM> to provide the sounds PVS by the vibration of the first area of the display module <NUM>. The second sound generating unit <NUM> may vibrate the second rear area of the display module <NUM> to provide the sounds PVS by the vibration of the second area of the display module <NUM>. Accordingly, the display apparatus may output two channel stereo sounds by separating left and right sounds using the first and second sound generating units. In this case, the first sound generating unit <NUM> may be configured to output the left ear sound, and the second sound generating unit may be configured to output the right ear sound.

In one example, at least one sound generating unit <NUM> may be disposed inside of the back cover <NUM> to provide the sounds PVS by vibrating the display module <NUM>. That is, the sound generating unit <NUM> may be surrounded by the back cover <NUM> so that it is concealed without being exposed to the outermost rear surface of the display apparatus. Therefore, the display apparatus according to the embodiment of the present disclosure may have a clean back design that is inconspicuous to the user so that the design of rear structure of the display apparatus may be visually enhanced.

In one example, at least one sound generating unit <NUM> may be a single structure or a single element modularized as a single component. In detail, the sound generating unit <NUM> may be manufactured in the form of a final product such as a single structure or a single element by a modularization process (or an assembly process) not included in an assembly process of the display device. After that, during the assembly process of the display apparatus, the sound generating unit <NUM> may be mounted or installed at the step portion TH provide inside of the back cover <NUM> by a component mounting process. Accordingly, the present disclosure may improve the assembling process of the sound generating unit <NUM> to the display apparatus, thereby enhancing the production yield.

The display apparatus according to the first embodiment of the present disclosure may further include a guide panel <NUM>. The guide panel <NUM> may support the circumferences of the display module <NUM> and the back cover <NUM>, respectively, and may have a structure surrounding each side surface of the display module <NUM> and the back cover <NUM>.

In one example, the guide panel <NUM> may be attached to a circumferential portion, e.g. the rear circumferences, of the display module <NUM> or the rear cover <NUM> with a guide adhesive <NUM>. The guide panel <NUM> may be expressed as a middle cabinet, a middle cover, or a middle chassis, but it is not limited thereto.

In one example, the guide panel <NUM> may include a metal material or a plastic material. In detail, the guide panel <NUM> may be preferably made of a metal material to improve the side appearance design of the display apparatus and to protect the side surface of the display apparatus.

In one example, the guide panel <NUM> may include a supporting element <NUM> and a side wall <NUM>.

The supporting element <NUM> may be coupled to the back cover <NUM> by being inserted into a groove formed in a side surface of the back cover <NUM>. The front surface of the supporting element <NUM> may be combined with the surface of one side of the groove of the back cover <NUM> using the guide adhesive <NUM>. The support element <NUM> may have any thickness, but it is preferable that it is easy to engage with the back cover <NUM> and it has sufficient rigidity so that it is not easily separated from the back cover <NUM>.

In one example, the supporting element <NUM> may have a single frame structure in a square shape, but it is not limited thereto. For example, the supporting element <NUM> may have a plurality of split bar shapes that are inserted into the groove or edge of the back cover <NUM>.

The guide adhesive <NUM> may be disposed between the groove of the back cover <NUM> and any one surface, in particular an inner side, of the supporting element <NUM>. The guide adhesive <NUM> may be an adhesive resin, a double-side tape, or a double-side adhesive foam pad, but it is not limited thereto.

The side wall <NUM> may be vertically or perpendicularly coupled to the outer surface of the supporting element <NUM> to be parallel to the thickness direction Z of the display apparatus. The side wall <NUM> may surround both the outer surface (or, outer wall) of the display module <NUM> and the outer surface of the back cover <NUM>. Accordingly, the side wall <NUM> may protect the outer surface of each of the display module <NUM> and the back cover <NUM> so as to improve the stability and outer design of the side surface of the display apparatus. In one example, the guide panel <NUM> may have a frame structure having a cross-sectional structure of a " <IMG>" shape as the supporting element <NUM> are coupled to each other to form a single body.

The display apparatus according to the present disclosure may include an adhesive element additionally to or instead of the guide panel <NUM>. Interposed between the rear edge of the display module <NUM> and the front edge of the back cover <NUM>, the adhesive element may bond the display module <NUM> and the back cover <NUM>.

In the case that the display apparatus includes the adhesive element instead of guide panel <NUM>, the back cover <NUM> may include a side wall cover portion surrounding both the outer surface (or outer wall) of the display module <NUM> and the outer surface of the back cover <NUM> and the outer surface of the adhesive elment.

According to the display apparatus according to the present disclosure, the display panel <NUM> may be vibrated by the sound generating unit <NUM> disposed inside the back cover <NUM> bonded to the rear surface of the display module <NUM>, and the sounds PVS generated by this vibration may be output to forward direction FD. Therefore, the viewer's immersion as viewing the video information of the display apparatus may be improved.

Further, according to the first embodiment of the present disclosure, the display apparatus may provide the sounds PVS from the vibration of the display panel <NUM>, so that it is not required additional speaker. Accordingly, it can improve the degree of the freedom for the design of the set device and the placement of the speakers.

Hereinafter, in various embodiments of the present disclosure, the mounting structure of the sound generating unit <NUM>, particularly the piezo vibration unit PZ, which is a core configuration of this disclosure, in the back cover <NUM> is described in more detail.

<FIG> is an enlarged cross-sectional view illustrating a structure of a display apparatus according to the second embodiment of the present disclosure. <FIG> is an enlarged view of a portion indicated by circle A in <FIG>. Hereinafter, the main configuration of the second embodiment will be mainly explained. The configurations not shown in <FIG> may be referred to <FIG>.

Referring to <FIG>, the display apparatus according to the second embodiment of the present disclosure may comprise a display module <NUM>, a back cover <NUM> and a piezo vibtration unit PZ. The display module <NUM> may be same as the first embodiment, so detail explanation will not be duplicated.

The back cover <NUM> may be also same with the first embodiment, excepting the detailed structures of the penetration S1 and the depression S2. The back cover <NUM> may include a penetration S1 and a depression S2. The penetration S1 and the depression S2 may overlap. A through hole in the back cover <NUM>, i.e. from a rear surface 700D to a front surface 700U of the back cover <NUM>, may be formed by the penetration S1 and the depression S2. The depression S2 may have a well shape in which some material or depths from the rear surface 700D of the back cover <NUM> to the inside of the back cover <NUM> are removed or recessed. The penetration S1 may have a through hole shape, and may be formed by removing from the front surface 700U of the back cover <NUM> to the depression S2 through the back cover <NUM>. That is, the sum of the depth of the penetration S1 and the depth of the depression S2 may be corresponding to the whole thickness of the back cover <NUM>. In other words, the penetration S1 may be a through hole extending from the front surface 700U of the back cover <NUM> to the depression S2 through the back cover <NUM>.

The penetration S1 and the depression S2 are connected to each other to have a structure passing through the back cover <NUM>. However, the depression S2 is not the structure for penetrating the back cover <NUM>, but for mounting the piezo vibration unit PZ inside of the back cover <NUM>. Therefore, the depression S2 may be referred to as a recessed portion, a sinkhole, or a subside portion, but it is not limited thereto. On the contrary, the penetration S1 may be formed as to provide a space for transmiting the vibration generated from the sound generating unit <NUM>, e.g. the piezo vibration unit PZ, mounted at the depression S2 to the rear surface of the display panel <NUM> exactly or accurately. Therefore, the penetration S1 may be referred to as an opening, a through hole or a perforation, but it is not limited thereto.

Accordingly, in the cross-section view of the penetration S1 and depression S2, a stepped structure may be formed between the front surface 700U of the back cover <NUM> and the rear surface 700B of the back cover <NUM>. For example, the penetration S1 may have a first width and a first depth. The first width may be corresponding to the width of the opening formed at the front surface 700U of the back cover <NUM>. The first depth may be corresponding to the recessed depth of the opening extended inward of the back cover <NUM>. For example, the first depth may be corresponding to the length of the side wall <NUM> of the penetration S1. The inner side wall <NUM> may extend from the front surface 700U of the back cover <NUM> toward the rear surface 700D of the back cover <NUM>. In addition, in order to suppress the resonance phenomenon to the sound generated by the piezo vibration unit PZ, the cross-sectinal profile of the side wall <NUM> of the penetrating S1 may be formed to have a sawtooth or wave shape instead of a straight line. Further, the shape of the opening (on the top view) of the penetrating S1 may be formed to have a serrated irregular closed curve, not a circular or polygonal curve.

The depression S2 may be corresponding to a space provided between a middle surface <NUM> and the rear surface 700D of the back cover <NUM>, in which the middle surface <NUM> may be expanded from an inner end of the side wall <NUM> of the penetration S1 in a horizontal direction of the back cover <NUM>, that is a direction in parallel to the rear surface 700D and/or the front surface 700U of the back cover <NUM>. For example, the depression S2 may have a second width and a second depth. The second width may be corresponding to the width of the opening formed at the rear surface 700D of the back cover <NUM>. The second depth may be corresponding to the recessed depth of the opening of the depression S2 extended inward the back cover <NUM>. For example, the second depth may be corresponding to the length of the side wall <NUM> of the depression S2. The side wall <NUM> may extend from the rear surface 700D of the back cover <NUM> toward the front surface 700U of the back cover <NUM>. The middle surface <NUM> may connect the inner side wall <NUM> and the side wall <NUM> in the horizontal direction of the back cover <NUM>. That is, the middle surface <NUM> may be arranged between the depression S2 and the penetration S1 and/or may form the stepped portion TH. The middle surface <NUM> may have a ring shape.

Here, the second width meaning the size of the opening of the depression S2 may be larger than the first width meaning the size of the opening of the penetration S1. The second depth meaning the depth of the depression S2 may be same with the first depth meaning the depth of the penetration S1. The penetration S1 and the depression S2 may be arranged so that their centers overlap each other to have a symmetrical shape, but it is not limited thereto. Otherwise, the penetration S1 may be disposed to be biased to the depression S2.

The piezo vibration unit PZ according to the second embodiment may include a piezo vibrator (or piezoelectric vibrator) PE and a metal substrate SU. The piezo vibrator PE may be referred to as a piezoelectric resonator or a piezoelectric actuator. The piezoelectric vibrator PE refers to a device that generates vibration by applying an electric field using the principle that a distortion occurs when an electric field is applied to two different types of crystals, or a piezoelectricity is generated when an external force is applied to the crystals.

The metal substrate SU may be disposed at or adjacent to the middle surface <NUM> between the depression S2 and the penetration S1 formed at the back cover <NUM>. For example, using an adhesive element AH, the metal substrate SU may be attached at the middle surface <NUM>. The piezo vibrator PE may be attached at the rear surface of the metal substrate SU.

For example, the piezo vibrator PE and the metal substrate SU may be made as one body and the circumferences of the metal substrate SU may be attached at the middle surface <NUM> using the adhesive element AH.

When piezo vibrator PE generates the vibrations by the electric force, the air in the penetration S1 may be vibrated by the movement of the piezo vibrator PE, in particular of the metal substrate SU, so that a sound pressure may be generated. This sound pressure may be transmitted to the rear surface of the display module <NUM>, and a portion of the display module <NUM> exposed by the penetration S1 may be vibrated. The vibration may be transmitted to the entire display module <NUM>. Sound generated based on the vibration of the display module <NUM> may be transferred to the front surface or the front direction of the display module <NUM> and the display apparatus.

Here, the vibration generated by the piezo vibrator PE may be determined as a vibration or sound wave of a predetermined band in accordance with the type and thickness of the metal substrate SU. For example, when the thickness of the metal substrate SU is thin, a high-frequency vibration or sound may be generated, and when the thickness is thick, a low-frequency sound may be generated.

In addition, the vibration generated by the piezo vibrator PE may be also determined as a vibration or sound wave of a predetermined band in accordance with the volume of the penetration S1. For example, as the volume of the penetration S1 is increased, lower and lower vibration or sound frequency vibrations may be generated. In some examples, adjusting the volume and shape of the penetration S1, the sound quality may be expressed differently.

<FIG> is an enlarged cross-sectional view illustrating a structure of a display structure according to the third embodiment of the present disclosure. <FIG> is an enlarged view of a portion indicated by circle A in <FIG>. Hereinafter, main elements of the third embodiment will be explained. For the elements not shown in <FIG>, <FIG> may be referred.

Referring to <FIG>, the display apparatus according to the third embodiment of the present disclosure may comprise a display module <NUM>, a back cover <NUM> and a piezo vibration unit PZ. The display module <NUM> may be same as the first embodiment, so detail explanation will not be duplicated.

In the third embodiment, the piezo vibration unit PZ may include a piezo vibrator PE and a metal substrate SU. The piezo vibrtor PE may be disposed at or adjacent to the middle surface <NUM> between the depression S2 and the penetration S1 formed inside of the back cover <NUM>. For example, using an adhesive element AH, the piezo vibrator PE may be attached at the middle surface <NUM>. The metal substrate SU may be attached at the rear surface of the piezo vibrator PE.

When piezo vibrator PE generates the vibrations by the electric force, the air in the penetration S1 may be vibrated and then a sound pressure may be generated. This sound pressure may be transmitted to the rear surface of the display module <NUM>, and a portion of the display module <NUM> exposed by corresponding to the penetration S1 may be vibrated, so that the sound or vibration may be transmitted to the entire display module <NUM>. Sound generated based on the vibration of the display module <NUM> may be transferred to the front surface or the front direction of the display module <NUM> and the display apparatus.

Using the metal substrate SU attached at the rear surface of the piezo vibrator PE, the frequency band of the vibration or sound generated by the piezo vibrator PE may be adjusted. In addition, the heat generated from the piezo vibrator PE may be radiated to the depression S2 and an external environment of the depression S2.

<FIG> is an enlarged cross-sectional view illustrating a structure of a display apparatus according to the fourth embodiment of the present disclosure. <FIG> is an enlarged view of a portion indicated by circle A in <FIG>. Hereinafter, main elements of the fourth embodiment will be explained. For the elements not shown in <FIG>, <FIG> may be referred.

Referring to <FIG>, the display apparatus according to the fourth embodiment of the present disclosure may comprise a display module <NUM>, a back cover <NUM> and a piezo vibration unit PZ. The display module <NUM> may be same as the embodiments explained above, so detail explanation will not be duplicated.

The piezo vibration unit PZ according to the fourth embodiment may comprise a piezo vibrator PE, a first metal substrate SU2 and a second metal substrate SU1. The piezo vibration unit PZ according to the fourth embodiment may have all characteristics of the piezo vibration unit PZ according to the second and the third embodiments.

The first metal substrate SU2 may be disposed at or adjacent to the middle surface <NUM> between the depression S2 and the penetration S1 formed at the back cover <NUM>. For example, using an adhesive element AH, the first metal substrate SU2 may be attached at the middle surface <NUM>.

The piezo vibrator PE may be attached at the rear surface of the first metal substrate SU2. The piezo vibrator PE may be attached at the middle or center portion of the rear surface of the first metal substrate SU2. In another example, even though not shown in figures, the whole surface of the first metal substrate SU2 may have the same size as the piezo vibrator PE.

The second metal substrate SU1 may be attached at the rear surface of the piezo vibrator PE. For example, the second metal substrate SU1 may be formed as an integrated body shape with the piezo vibrator PE covering the whole rear surface of the piezo vibrator PE.

In one example, the first metal substrate SU2, the piezo vibrator PE and the second metal substrate SU1 may be formed as one body, and then the circumference portion of the first metal substrate SU2 may be attached at the middle surface <NUM> using the adhesive element AH.

When the piezo vibrator PE generates the vibrations by the electric force, the air in the penetration S1 may be vibrated and then a sound pressure may be generated. This sound pressure may be transmitted to the rear surface of the display module <NUM>, and the portion of the display module <NUM> corresponding to the penetration S1 may be vibrated. the sound or vibration may be transmitted or propagated to the entire display module <NUM>. Sound generated based on the vibration of the display module <NUM> may be transferred to the front surface or the front direction of the display module <NUM> and the display apparatus.

Using the first metal substrate SU2 attached at the front surface of the piezo vibrator PE and the second metal substrate SU1 attached at the rear surface of the piezo vibrator PE, the frequency band of the vibration or sound generated by the piezo vibrator PE may be adjusted to be wider and more diversely. In addition, as the first metal substrate SU2 and the second metal substrate SU1 are disposed at both surfaces of the piezo vibrator PE, the heat generated from the piezo vibrator PE may be radiated to the external environment, through the penetration S1 and/or the depression S2 more effectively. That is, comparing with the third embodiment, by providing one more metal substate, a higher quality sound may be obtained, and the heat dissipation effect may be more excellent.

<FIG> is an enlarged cross-sectional view illustrating a structure of a display apparatus according to the fifth embodiment of the present disclosure. The structure of the display apparatus according to the fifth embodiment as shown in <FIG> may be very similar with the structure of the display apparatus according to the first embodiment. The difference is that the volume of the penetration S1 may be remarkably smaller than the volume of the depression S2. On the contrary with the <FIG>, even though not shown in figures, the volume of the penetration S1 may be remarkably larger than the volume of the depression S2. The volume of the penetration S1 and the depression S2 may be adjusted by adjusting a width and/or a depth, that is a length, of the penetration S1 and the depression S2, respectively.

By setting or adjusting the volume of the penetration S1, the bandwidth of the sound generated by the piezo vibration unit PZ may be adjusted. For example, when the piezo vibration unit PZ is designed to generate vibration or sound of a high-frequency sound band, the volume of the penetrating S1 may be formed as small as possible. Conversely, when the piezo vibration unit PZ is designed to generate vibration or sound of a low-frequency sound band, the volume of the prenetrating S1 as large as possible.

Although not shown in the figures, when setting the volume of the penetration S1, the side wall <NUM> of the penetration S1 may be formed in a diagonal line instead of a vertical line in a cross-sectional view so that the volume of the penetration S1 may be variously designed. In addition, in order to suppress the resonance phenomenon to the sound generated by the piezo vibration unit PZ, the cross-sectinal profile of the side wall <NUM> of the penetrating S1 may be formed to have a sawtooth or wave shape instead of a straight line. Further, the shape of the opening (on the top view) of the penetrating S1 may be formed to have a serrated irregular closed curve, not a circular or polygonal curve.

In the embodiments explained above, various examples have been described for the cases in which one sound generation unit <NUM> comprises only one piezo vibration unit PZ. Hereinafter, various embodiments for cases in which two piezo vibration unit PZ are provided in one sound generating unit <NUM> will be explained.

<FIG> is is an enlarged cross-sectional view illustrating a structure of a display apparatus according to the sixth embodiment of the present disclosure. When necessary, it will be described with reference to <FIG> showing the overall structure of the display apparatus according to the present disclosure.

Referring to <FIG>, the display apparatus according to the sixth embodiment of the present disclosure may comprise a display module <NUM>, a back cover <NUM> and a sound generating unit <NUM>. It is preferable that the sound generating unit <NUM> may be implemented as having a piezo vibration unit PZ which is coupled to the rear surface of the display module <NUM> suitable for mounting inside the back cover <NUM>. For example, the sound generating unit <NUM> may include a piezoelectric element or an electric active material (EAM).

The display module <NUM> may include a display panel <NUM>, a functional film <NUM> and a heat diffusion element <NUM>. The display module <NUM> may be same with the embodiments explained above, the duplicated explanation will not be duplicated.

The back cover <NUM> may be disposed at the rear surface of the display panel <NUM>. The sound generating unit <NUM> may be mounted or installed inside of the back cover <NUM>. For example, the back cover <NUM> may be attached at the rear surface of the display module <NUM> using an adhesive element <NUM>. The adhesive element <NUM> may include a pressure sensitive adhesive (PSA), an optical clear adhesive (OCA), or and optical clear resin (OCR), but it is not limited thereto. The back cover <NUM> may be attached to the whole of the rear surface of the display module <NUM>. The back cover <NUM> may protect the rear surface of the display module <NUM> from external shocks and radiate the heat generated from the display module <NUM> to the external environment.

The back cover <NUM> includes an upper depression Sa, a penetration Sb and a lower depression Sc. The upper depression Sa may have a well shape in which a portion of the back cover <NUM> with a first thickness is removed from the front surface 700U inward of the back cover <NUM>. The lower depression Sc may have a well shape in which another portion of the back cover <NUM> with a second thickness is removed from the rear surface 700D inward of the back cover <NUM>. Further, the penetration Sb is a through hole penetrating the remaining back cover <NUM> between the upper depression Sa and the lower depression Sc. Therefore, viewing in a cross-section, a stepped or protruding portion 700C surrounding or forming the penetration Sb may have a structure protruding between the upper depression Sa and the lower depression Sc. The upper depression Sa, the lower depression Sc and the penetration Sb may overlap each other and/or may be eccentrically arranged. The stepped prtion 700c may have a ring shape. The upper depression Sa, the lower depression Sc and the penetration Sb form a through-hole through the back cover <NUM> from the front surface 700U to the rear surface 700D. The upper depresson Sa, the lower depression Sc and/or the penetration Sb each may have a circular or cylindrical shape.

As the upper depression Sa, the penetration Sb and the lower depression Sc are continuously formed, the through hole may be formed as one body. In other words, the stepped portion 700C may be formed as one body with the remaining portions of the back cover <NUM>. The penetration Sb may have a smaller width (or diameter) than the width of the upper depression Sa or the lower depression Sb. Accordingly, a first stepped portion TH1 is formed between the upper depression Sa and the penetration Sb, and a second stepped portion TH2 is formed between the lower depression Sc and the penetration Sb. Here, the depth of the penetration Sb and the depth of the upper depression Sa or the depth of the lower depression Sc may be same. Otherwise, one of them may be larger than others. In <FIG>, the upper depression Sa and the lower depression Sc have the same depth, and the penetration Sb has smaller depth than those of the upper and lower depressions Sa and Sc. Defined differently, the second depth of the penetration Sb may be defined as the length of the penetration Sb measured from the front surface of the back cover <NUM>, i.e. the sum of the length of the side wall <NUM> and the length of the side wall <NUM>.

The upper depression Sa, the penetration Sb and the lower depression Sb are connected or linked continuously so that the back cover <NUM> is totally penetrated. However, the upper depression Sa and the lower depression Sc are not penetrating the back cover <NUM>. The upper depression Sa is a structure for installing the first piezo vibration unit PZ1 and the lower depression Sc is a structure for installing the second piezo vibration unit PZ2. The penetration Sb is a structure for preparing a space for transmitting the acoustic vibration generated from the first and/or second piezo vibration units PZ1 and PZ2 to the rear surface of the display panel <NUM>.

Therefore, according to the cross-sectional view of the upper depression Sa, the penetration Sb and the lower depression Sc, an irregular (or stepped) shape is formed between the front surface 700U and the rear surface 700D of the back cover <NUM>. The upper depression Sa has a first width and a first depth. The first width may refer to the width of the opening formed at the front surface 700U of the back cover <NUM>. The first depth may refer to the length of the opening of the upper depression Sa extending inward of the back cover <NUM> from the front surface 700U. For example, the first depth of the upper depression Sa may be corresponding to the length of the side wall <NUM> of the upper depression Sa. The side wall <NUM> may extend from the front surface 700U of the back cover <NUM> inward of the back cover <NUM> and may have a ring shape.

The penetration Sb has a second width and a second depth. The second width may refer to the width of the opening formed at the stepped portion 700C. The second depth may refer to the depth through which the penetration Sb penetrates the stepped portion 700C. For example, the second depth may be corresponding to the length of the side wall <NUM> of the penetration Sb. The side wall <NUM> may extend from the upper surface <NUM> to the lower surface <NUM>. The side wall <NUM> may surround or form the penetration Sb in a direction perpendicular to the front or rear surfaces of the back cover <NUM>. Defined differently, the second depth of the penetration Sb may be defined as the length of the penetration Sb measured from the front surface of the back cover <NUM>, i.e. the sum of the length of the side wall <NUM> and the length of the side wall <NUM>.

The lower depression Sc has a third width and a third depth. The third width may refer to a width of the opening formed at the rear surface 700D of the back cover <NUM>. The third depth may refer to the length of the opening of the lower depression Sc extending inward of the back cover <NUM> from the rear surface 700D. For example, the third depth of the lower depression Sc may be corresponding to the length of the side wall <NUM> of the upper depression Sa. The side wall <NUM> may extend from the back surface 700d inward.

The stepped or protruding portion 700C may have the extruded structure, the stepped portion 700C may have an upper surface <NUM>, side wall <NUM> of the penetration Sb and a lower surface <NUM>. For example, the upper surface <NUM> may be a plane perpendicular to and linking the lower side of the side wall <NUM> of the upper depression Sa and the upper side of the side wall <NUM> of the penetration Sb. The lower surface <NUM> may be a plane linking the lower side of the side wall <NUM> of the penetration Sc and the side wall <NUM> of the lower depression Sc. The side wall <NUM> may have a ring shape.

Here, the first width meaning the opening size or diameter of the upper depression Sa is larger than the second width meaning the opening size or diameter of the penetration Sb. Further, the first depth meaning the depth or length of the upper depression Sa may be larger than the second depth meaning the depth or length of the penetration Sb. The third width meaning the opening size of the lower depression Sc may be same with the first width. In addition, the third depth meaning the depth or length of the lower depression Sc may be the same or different from the first depth.

The upper depression Sa, the penetration Sb and the lower depression Sc may be concentrically arranged. The upper depression Sa, the penetration Sb and the lower depression Sc may be arranged so that the centers are overlapped to form a concentric shape, but it is not limited thereto. Each of the centers may be relatively biased and be arranged to one side.

In the sixth embodiment, the sound generating unit <NUM> includes a first piezo vibration unit PZ1 and a second piezo vibration unit PZ2. The first piezo vibration unit PZ1 may be attached to the upper surface <NUM> of the stepped portion 700C using a first adhesive AH1. The second piezo vibration unit PZ2 may be attached to the lower surface <NUM> of the stepped portion 700C using a second adhesive AH2. The first piezo vibration unit PZ1 may be arranged in the upper depression Sa. The second piezo vibration unit PZ1 may be arranged in the lower depression Sc.

For example, the first piezo vibration unit PZ1 may include a first piezo vibrator PE1 and a first metal substrate SU1. The first metal substrate SU1 may be installed at the upper surface <NUM> of the stepped portion 700C disposed between the upper depression Sa and the penetration Sb. For example, using the first adhesive AH1, the first metal substrate SU1 may be attached on the upper surface <NUM> of the stepped portion 700C. In addition, the first piezo vibrator PE1 may be attached on the upper surface of the first metal substrate SU1. The first and second metal substrates SU1 and SU2 may face each other, in particular symmetrically, and/or may overlap each other. The first and second metal substrates SU1 and SU2 may have a circular shape.

Further, the second piezo vibration unit PZ2 may include a second piezo vibrator PE2 and a second metal substrate SU2. The second metal substrate SU2 may be installed at the lower surface <NUM> of the stepped portion 700C disposed between the lower depression Sc and the penetration Sb. For example, using the second adhesive AH2, the second metal substrate SU2 may be attached on the lower surface <NUM> of the stepped portion 700C. In addition, the second piezo vibrator PE2 may be attached on the lower surface of the second metal substrate SU2.

In another example, the first piezo vibration unit PE1 and the first metal substrate SU1 may be formed as one body, and a circumferential portion of the first metal substrate SU1 may be attached on the upper surface <NUM> of the stepped portion 700C using the first adhesive AH1. Further, the second piezo vibration unit PE2 and the second metal substrate SU2 may be formed as one body, and a circumferential portion of the second metal substrate SU2 may be attached on the lower surface <NUM> of the stepped portion 700C using the second adhesive AH2.

When the first and second piezo vibrators PE1 and PE2 generate the vibrations by the electric force, the air in the upper depression Sa and in the penetration Sb may be vibrated by the first and the second metal substrates SU1 and SU2, and then a sound pressure may be generated. This sound pressure may be transmitted to the rear surface of the display module <NUM>, and a portion of the display module <NUM> corresponding to the opening, that is the upper depression Sa, may be vibrated. Sound or vibration may be transmitted or propagated to the entire display module <NUM>. Sound generated based on the vibration of the display module <NUM> may be transferred to the front surface or the front direction of the display module <NUM> and the display apparatus.

Here, according to the kinds of the thicknesses of the first and the second metal substrates SU1 and SU2, the vibrations generated by the first and the second piezo vibrators PE1 and PE2 may be defined to have a certain bandwidth , frequency or sound band. For example, as the thicknesses of the first and second metal substrates SU1 and SU2 become thinner and thinner, the sound or vibration may have a higher frequency or bandwidth. As the thicknesses of the first and second metal substrates SU1 and SU2 become thicker and thicker, the sound vibration may have a lower frequency or bandwidth.

In addition, when the first piezo vibrator PE1 and the second piezo vibrator PE2 generate the sound vibration in the same frequency bandwidth having the same phase with each other, a resonance effect of amplifying the volume can be obtained, because of the structure in which the first and second metal substrates SU1 and SU2 are facing each other symmetrically. For example, the first piezo vibrator PE1 and the second piezo vibrator PE2 may be constituted by a piezoelectric element or an electrical active material and the polarities of the driving voltages are opposite to each other. In this case, as shown in <FIG>, it is possible to obtain an effect of resonating such that the amplitude of the sound vibration may be multipled due to the symmetrical arrangement structure. As a result, a <NUM>-way structure with an increased amount of the amplitude and an increased sound pressure may be acquired.

With the structure of the sixth embodiment of the present disclosure, in a thin structure display apparatus, rich sound quality with improved amplitude and sound pressure may be obtained without mounting a speaker that is easily visible from the outside.

<FIG> is an enlarged cross-sectional view illustrating a structure of a display apparatus according to the seventh embodiment of the present disclosure. The display apparatus according to the seventh embodiment of the present disclosure shown in <FIG> may have the very similar strcutrue with the sixth embodiment shown in <FIG>. The difference is that the first piezo vibrator PE1 has a different size from the second piezo vibrator PE2, as shown in the seventh embodiment.

The size difference between the first piezo vibrator PE1 and the second piezo vibrator PE2 is not merely to show the size, but to show the difference in the bandwidth of the sound vibration. For example, a small sized vibrator may generate sound vibration in a higher frequency bandwidth than a large sized vibrator. As shown in <FIG>, the first piezo vibrator PE1 may be disposed in the upper depression Sa for generating high-frequency sound vibration. The second piezo vibrator PE2 may be disposed in the lower depression Sc for generating low-frequency sound vibration.

In one example, the first piezo vibrator PE1 may be a small area piezoelectric element or an EAM capable of implementing a tweeter. The second piezo vibrator PE2 may be a large area piezoelectric element or EAM capable of implementing a woofer.

In the display apparatus according to the seventh embodiment of the present disclosure, by placing two vibrators generating sound vibrations of different frequency bandwidths in a stacked strcutrue in the same space, the display apparatus can generate sounds of various frequency bandwidths. Therefore, by providing a high frequency sound and a mid-range sound separately without having a speaker exposed to the appearance of the very thin display apparatus, richer sound quality can be provided.

<FIG> is an enlarged cross-sectional view illustrating a structure of a display structure according to the eighth embodiment of the present disclosure. The display apparatus according to the eighth embodiment of the present disclosure shown in <FIG> may have a very similar structure with the seventh embodiment shown in <FIG>. The difference is that the first piezo vibrator PE1 is disposed at the different position from the second piezo vibrator PE2, in the eighth embodiment.

As shown in <FIG>, the second piezo vibrator PE2 generating sounds of a low frequency bandwidth may be disposed at the upper depression Sa, and the first piezo vibrator PE1 generating sounds of high frequency bandwidth may be disposed at the lower depression Sc. For example, the first piezo vibrator PE1 may be a small area piezoelectric element or an EAM capable of implementing a tweeter. The second piezo vibrator PE2 may be a large area piezoelectric element or EAM capable of implementing a woofer.

In the display apparatus according to the eighth embodiment of the present disclosure, by placing two vibrators generating sound vibrations of different frequency bandwidths in a stacked structure in the same space, the display apparatus can generate sounds of various frequency bandwidths. Therefore, by providing a high frequency sound and a mid-range sound separately without having a speaker exposed to the appearance of the very thin display apparatus, richer sound quality and a neater outer appearance of the display apparatus can be provided.

The frequency bandwidth may refer to the tone height of the sound. The audible frequency, <NUM> to <NUM>,<NUM>, may be divided into <NUM> octaves, and it is divided into low, mid and high ranges of frequencies. In detail, it can be classified as follows.

In the seventh and eighth embodiments of the present disclosure, each piezo vibrator may be configured to generate vibrations or sounds of different frequency bandwidths, thereby providing richer sound quality.

When adapting a piezoelectric element, it is preferable to be able to transmit the high-frequency sounds, efficiently. Especially, to maintain the sound pressure of the <NUM> bandwidth sounds, the space design of the penetration may be very important.

For example, for the cases of the first to fifth embodiments explained with <FIG>, it is very important to design the space of the penetration S1 when the vibration generated from the piezo vibration unit PZ is reflected by the rear surface of the display panel <NUM>, so as not to affect the phase of the vibration of the piezo vibration unit PZ. In order to prevent the phase change from occurring, as shown in equation <NUM> below, the arrival time of the echo sound must be equal to or less than <NUM>/<NUM> of the period of the sound bandwidth. In the following equation, the maximum spatial separation distance which is not affected by the reverberation, is calculated from the frequency of <NUM> which is a reference for the high frequency sound.

Here, '<NUM>' refers to the arrival time of the echo sound, 'f' refers to the frequency of sound.

Therefore, the effective distance of the penetration S1, that is the first depth, may become `<NUM>/sec X <NUM> sec = <NUM> = <NUM>', when calculating based on the sound speed of <NUM>/sec. In the first to fifth embodiments, when the piezo vibration unit PZ generates a sound of <NUM>, the depth of the penetration S1 may have a value of <NUM> or less.

In the above embodiments, in consideration of the frequency bandwidth generated from the piezo vibration unit PZ to be applied, the depth or length of the upper depression Sa, the penetration Sb and/ the penetration S1 may be designed to provide high quality sounds without being canceled out or disappeared.

<FIG> is an enlarged cross-sectional view illustrating a structure of a display apparatus according to the ninth embodiment of the present disclosure. In the ninth embodiment, a case in which a heat radiating metal plate that can be applied to all of the previous embodiments may be further configured will be described.

<FIG> is an enlarged cross-sectional view illustrating an example in which a heat radiating metal plate HP is further included in the <FIG> showing the first embodiment of the present disclosure. Referring to <FIG>, the display apparatus according to the ninth embodiment of the present disclosure may comprise a display module <NUM>, a back cover <NUM>, a heat radiating metal plate HP and a sound generating unit <NUM>. The display module <NUM>, the back cover <NUM>, and the sound generating unit <NUM> may be selected any one of the embodiments explained above.

Additionally, the heat radiating metal plate HP may be included. Specifically, the heat radiating metal plate HP may be attached a portion of the rear surface of the display module <NUM> exposed by the penetration S1. Otherwise, the heat radiating metal plate HP may be another portion of the rear surface of the display module <NUM> exposed by the upper depression Sa. The heat radiating metal plate HP may be attached on the adhesive element <NUM> applied to the rear surface of the display module <NUM> for joining the back cover <NUM> to the rear surface of the display panel <NUM>.

Further including a heat radiating metal plate HP attached to the rear surface of the display panel <NUM> opposite the vibration generating unit <NUM>, the display panel according to the ninth embodiment of the present disclosure may induce the heat generated by the piezo vibration unit PZ to be easily discharged into the air without being directly transferred to the display module <NUM>. That is, the heat radiation metal plate HP may take up the heat generated by the piezo vibration unit PZ.

<FIG> is an enlarged cross-sectional view illustrating a structure of a display structure according to the tenth embodiment of the present disclosure. <FIG> is an enlarged view of a portion indicated by circle A in <FIG>. Hereinafter, the main configuration of the tenth embodiment will be mainly explained. The configurations not shown in <FIG> may be referred to <FIG>.

Referring to <FIG>, the display apparatus according to the tenth embodiment of the present disclosure may comprise a display module <NUM>, a back cover <NUM>, a piezo vibtration unit PZ and an enclosure EN. The display module <NUM> may be same as the first embodiment, so detail explanation will not be duplicated.

In the tenth embodiment, the piezo vibration unit PZ may be disposed at the middle surface <NUM> between the depression S2 and the penetration S1. For an example, using an adhesive element AH, the piezo vibration unit PZ may be attached on the middle surface <NUM>. For another example, a metal substrate may be further included, as shown in <FIG> and <FIG>. In this embodiment, the metal substrate is not treated as an essential element.

In the tenth embodiment, the enclosure EN may be further provided for sealing the space of the depression S2 (or the lower depression Sc) in which the piezo vibration unit PZ is disposed. The enclosure EN may be made of an elastric material and/or may be inserted into the depression S2 from a rear surface of the back cover <NUM>. The enclosure EN may be arranged at a rear space of the piezo vibration unit PZ. As in the previous embodiments, the depression S2 or the lower depression Sc may be configured in an open state. In this case, the sound or sound waves generated from the vibration of the piezo vibration unit PZ may be output to the rear direction of the display apparatus from the back cover <NUM>, so that most of the sound may not be provided to the front direction of the display apparatus.

It is preferable to seal the depression S2 (or the lower depression Sc), that is a rear space of the open depression S2, so as to prevent sounds from being lost to the rear side of the display apparatus and to concentrate sounds in the front direction FD. To do so, the enclosure EN may have a lid shape corresponding to the depression S2, that is an opening area of the depression S2. Alternatively, although not shown in the drawings, the threads may be formed on the side <NUM> of the depression S2, and the threads may be also formed on the side of the enclosure EN, so that the enclosure may close or open the depression S2 in accordance with the interlocking structure of the threads.

When piezo vibration unit PZ generates the vibrations by the electric force, the air in the penetration S1 may be vibrated so that a sound pressure may be generated. This sound pressure may be transmitted to the rear surface of the display module <NUM>, and the display module <NUM> may be vibrated, so that the sound vibration may be transmitted to the entire display module <NUM>. Further, as the enclosure EN seals the depression S2 which is arranged at the rear space of the piezo vibration unit PZ, the sound or vibration reflected to the depression S2 may be reflected back by the enclosure EN to the front direction FD, that is to the rear surface of the display module <NUM>.

<FIG> is an enlarged cross-sectional view illustrating a structure of a display apparatus according to the eleventh embodiment of the present disclosure. <FIG> is an enlarged view of a portion indicated by circle A in <FIG>. Hereinafter, the main configurations of the eleventh embodiment will be explained. The configurations not shown in <FIG> may be referred to <FIG>.

Referring to <FIG>, the display apparatus according to the tenth embodiment of the present disclosure may comprise a display module <NUM>, a back cover <NUM> and a piezo vibtration module PM. The display module <NUM> may be same as the first embodiment, so detail explanation will not be duplicated.

Unlike the previous embodiments, the eleventh embodiment has a feature in which the piezo vibration module PM is included. The piezo vibration module PM may include a piezo vibration unit PZ and an enclosure EN formed as one body.

The piezo vibration unit PZ may be mounted inside the enclosure EN. Even though not shown in drawings, the outer edges or circumferential portion of the piezo vibration unit PZ may be attached to a mounting surface provided inside the enclosure EN using an adhesive. The enclosure EN may be configured such that a portion of an upper surface thereof facing the penetration S1 is opened so that vibration generated by the piezo vibration unit PZ can be transmitted to the penetration S1 without any losses. For another example, as shown in <FIG> and <FIG>, a metal substrate attached to an upper surface or a lower surface of the piezo vibration unit PZ may be further provided. In this embodiment, the metal substrate is not treated as an essential element.

The piezo vibration module PM may be disposed at the middle surface <NUM> between the depression S2 and the penetration S1 formed in the back cover <NUM>. For example, using an adhesive element AH, the piezo vibration module PM may be attached at the middle surface <NUM> or the.

The feature of the eleventh embodiment is that the piezo vibration unit PZ and the enclosure EN described in the tenth embodiment are designed as one module. The size and shape of the enclosure EN may be customized to have a space suitable for a sound bandwidth of the piezo vibration unit PZ. Further, by inserting and sealing the enclosure EN into the depression S2, the vibration element can be simply installed on the rear surface of the display panel <NUM>. In addition, even in the case of conducting repair works, the damaged piezo vibration module PM may be easily removed and a new piezo vibration module PM is re-installed simply.

The piezo vibration module PM has a structural feature of having its own enclosure EN for sealing the space of the depression S2 in which the piezo vibration PZ is disposed. When applied to the previous embodiments, all components of the display apparatus may be completed by simply inserting the piezo vibration module EN into the depression S2 or the bottom depression Sc.

Moreover, since the enclosure EN is built-in, it is possible to prevent sounds from being lost to the rear side of the display apparatus and to concentrate the sounds in the front direction FD of the display apparatus. The enclosure EN may have a cylindrical shape or a thin vessel shape corresponding to the opening area of the depression S2. The enclosure EN may be made of an elastic material and inserted into the depression S2. Alternatively, although not shown in the drawings, the threads may be formed on the side <NUM> of the depression S2, and the threads may be also formed on the outter side of the enclosure EN, so that the enclosure may close or open the depression S2 in accordance with the interlocking structure of the threads.

The enclosure EN has been described as having a structure for perfectly sealing the rear space of the piezo vibration unit PZ. However, it is not limited thereto. In some cases, the enclosure EN may further include a resonance hole having a predetermined size. In these cases, the enclosure EN may have a structure surrounding the rear space of the piezo vibration unit PZ rather than sealing it. The rear space of the piezo vibration unit PZ may basically correspond to the depression S2.

When piezo vibration unit PZ generates the vibrations by the electric force, the air in the penetration S1 may be vibrated so that a sound pressure may be generated. This sound pressure may be transmitted to the rear surface of the display module <NUM>, and the display module <NUM> may be vibrated, so that the sound vibration may be transmitted to the entire display module <NUM>. Further, as the enclosure EN seals the depression S2 which is the rear spce of the piezo vibration unit PZ, the sound vibratiob reflected by the depression S2 may be reflected back by the enclosure EN to the front direction FD.

The display apparatus according to the eleventh embodiment of the present disclosure may provide a modularized piezo vibration module PM. The piezo vibration module PM may be freely configured to have a resonance space by the enclosure EN, and it may be easy to configure and control a unique sound vibration mode. Therefore, it is possible to ensure the high sound quality in a desired sound bandwidth, especially in a high or upper bandwidth.

The embodiments of <FIG> may be applied or combined with all embodiments of <FIG>.

Features, structures, effects and so on described in the above described examples of the present disclosure are included in at least one example of the present disclosure, and are not necessarily limited to only one example. Furthermore, features, structures, effects and so on exemplified in at least one example of the present disclosure may be implemented by combining or modifying other examples by a person having ordinary skilled in this field. Therefore, contents related to such combinations and modifications should be interpreted as being included in the scope of the present application.

Claim 1:
A display apparatus comprising:
a display module (<NUM>) configured to display an image;
a back cover (<NUM>) disposed at a rear surface of the display module (<NUM>), the back cover (<NUM>) including a front surface and a rear surface parallelly facing each other to form a uniform thickness of the back cover (<NUM>);
a rear depression (S2, Sc) formed in the back cover (<NUM>) from the rear surface of the back cover (<NUM>) with a first width and a first depth;
a front depression (Sa) formed in the back cover (<NUM>) from the front surface of the back cover (<NUM>) with a third width and a third depth,
a through hole (S1, Sb) penetrating the back cover (<NUM>) from the front depression (Sa) to the rear depression (S2, Sc) with a second width and a second depth, the second width being smaller than the first width and the third width;
a first piezo vibration unit (PZ, PZ2) disposed at a first stepped portion (AH, TH, TH2) formed between the through hole (S1, Sb) and the rear depression (S2, Sc); and
a second piezo vibration unit (PZ1) disposed at a second stepped portion (TH1) formed between the front depression (Sa) and the through hole (S1, Sb).