Display device

Abstract

To provide a display device capable of accurate sound transmission to the front of a display panel.SOLUTION: A display device includes: a display module 100 having a display panel 110 for displaying an image; a rear cover 300 at the rear of the display module; a first vibration generating module 400 at a first rear region of the rear cover; and a second vibration generating module 500 at a second rear region of the rear cover. The rear cover includes a first hole 313 overlapping the first vibration generating module 400 and a second hole 315 overlapping the second vibration generating module 500.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present application relates to a display device, and more particularly to a display device having a display panel that outputs sound. [Background technology]

[0002] Generally, display devices are installed in electronic products and home appliances such as televisions, monitors, laptops, smartphones, tablet computers, electronic pads, wearable devices, watch phones, portable information devices, navigation systems, or vehicle control display devices, and are used as screens to display images.

[0003] A typical display device may include a display panel for displaying images, and an audio device for outputting sound associated with the video.

[0004] However, in a typical display device, sound output from a sound device travels behind or below the display panel, and sound quality is degraded due to interference between sounds reflected from walls and the floor (ground). This makes it difficult to transmit sound accurately and reduces the viewer's sense of immersion. Summary of the Invention

[0005] An object of the present invention is to provide a display device capable of accurate sound transmission.

[0006] An object of the present invention is to provide a display device that can improve sound quality and enhance a viewer's immersive feeling.

[0007] An object of the present invention is to provide a display device capable of generating sound that can travel in front of a display panel.

[0008] In addition to the above-mentioned technical objects of the present invention, other features and advantages of the present invention will be described below or will be clearly understood by those having ordinary skill in the art to which the present invention pertains from such descriptions and explanations.

[0009] A display device according to one embodiment of the present application includes a display module including a display panel for displaying images, a rear cover arranged on a rear side of the display module, a first vibration generating module arranged on a first rear area of ​​the rear cover, and a second vibration generating module arranged on a second rear area of ​​the rear cover, and the rear cover may include a first hole overlapping with the first vibration generating module and a second hole overlapping with the second vibration generating module.

[0010] A display device according to one embodiment of the present application includes a display module including a display panel for displaying images, a rear cover including a rear cover part covering a rear side of the display module, and a first vibration generating module and a second vibration generating module all arranged on the rear cover part and vibrating the display module, and the rear cover part may include a first gap arranged between the first vibration generating module and the display module, and a second gap arranged between the second vibration generating module and the display module.

[0011] According to one embodiment of the present application, a display device capable of accurate sound transmission can be provided, and a display device capable of improving sound quality and enhancing a viewer's immersive feeling can be provided.

[0012] According to an embodiment of the present application, a display device capable of outputting sound in front of a display panel can be provided.

[0013] In addition to the advantages of the present application described above, other features and advantages of the present application will be described below or will be clearly understood by those having ordinary skill in the art to which the present application pertains from such descriptions and explanations. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 illustrates a display device according to an embodiment of the present application. [Diagram 2] 2 is a diagram showing a vibration generating module disposed on a rear cover of the display device shown in FIG. 1. [Diagram 3] 2 is a cross-sectional view taken along line II' shown in FIG. 1. [Figure 4] FIG. 4 is an enlarged view of part 'A' shown in FIG. [Figure 5a] FIG. 2 is a diagram showing a system back cover shown in FIG. 1. [Figure 5b] FIG. 5b is an enlarged view of a duct located on the system back cover of FIG. 5a. [Figure 6] 5 is a diagram showing first and second sound generating units of the first vibration generating module shown in FIGS. 2 to 4. FIG. [Figure 7] 4 is a graph showing frequency and sound pressure characteristics of a first vibration generating module and a second vibration generating module according to an embodiment of the present application. [Figure 8] 4 is a graph showing the acoustic output characteristics of a display device according to an embodiment of the present application. [Figure 9] 4 is a graph showing the acoustic output characteristics of a display device according to an embodiment of the present application. [Figure 10] FIG. 2 is a diagram illustrating a Helmholtz resonator formed in a display device according to an embodiment of the present application. [Figure 11] 2 is another cross-sectional view of the line II' shown in FIG. 1 according to another embodiment of the present application. [Figure 12] FIG. 12 is an enlarged view of part B shown in FIG. [Figure 13] FIG. 12 is an enlarged view of part C shown in FIG. [Figure 14] FIG. 13 is a rear view of a display device according to another embodiment of the present application. [Figure 15] 15 is a cross-sectional view taken along line II-II' shown in FIG. 14. [Figure 16]FIG. 16 is a cross-sectional view of the rear cover shown in FIG. [Figure 17a] 1A to 1C are diagrams showing various arrangements of the first and second vibration generating modules in a display device according to an embodiment of the present application. [Figure 17b] 1A to 1C are diagrams showing various arrangements of the first and second vibration generating modules in a display device according to an embodiment of the present application. [Figure 17c] 1A to 1C are diagrams showing various arrangements of the first and second vibration generating modules in a display device according to an embodiment of the present application. [Figure 17d] 1A to 1C are diagrams showing various arrangements of the first and second vibration generating modules in a display device according to an embodiment of the present application. [Figure 17e] 1A to 1C are diagrams showing various arrangements of the first and second vibration generating modules in a display device according to an embodiment of the present application. [Fig. 17f] 1A to 1C are diagrams showing various arrangements of the first and second vibration generating modules in a display device according to an embodiment of the present application. [Figure 17g] 1A to 1C are diagrams showing various arrangements of the first and second vibration generating modules in a display device according to an embodiment of the present application. [Figure 18] 4 is a graph showing frequency-sound pressure characteristics according to the arrangement location of a second vibration generating module along a first direction in a display device according to an embodiment of the present application. [Figure 19] 11 is a graph showing frequency-sound pressure characteristics of a second vibration generating module according to first and second examples in a display device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The advantages and features of the present application, and the methods for achieving them, will become clear from the following detailed description of the embodiments with accompanying drawings. However, the present application is not limited to the embodiments disclosed below, and may be embodied in various different forms. The embodiments are provided merely to complete the disclosure of the present application and to fully inform those skilled in the art of the present application of the scope of the invention, and the present application is defined only by the claims.

[0016] The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present application are merely illustrative, and the present application is not limited to the matters shown in the drawings. The same reference numerals refer to the same components throughout the specification. In addition, in describing the present application, if a detailed description of related publicly known technology is deemed to unnecessarily obscure the gist of the present application, the detailed description will be omitted.

[0017] When the terms "including," "having," "consisting of," and the like are used as mentioned herein, other parts may be added unless "only" is used. When an element is expressed in the singular, the plural is included unless otherwise expressly stated.

[0018] When interpreting elements, they are to be interpreted as including a range of error even if there is no separate explicit description.

[0019] When describing a location relationship between two parts, for example "on top of", "on top of", "on bottom of", "next to", etc., one or more other parts may be located between the two parts, unless "immediately" or "directly" is used.

[0020] When describing a temporal relationship, for example when the temporal sequence is described using "after", "following", "next to", "before", etc., non-consecutive cases can also be included, as long as "immediately" or "directly" is not used.

[0021] Although the terms "first", "second" and the like are used to describe various components, these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component described below may be the second component within the technical concept of this application.

[0022] The term "at least one" should be understood to include all combinations that can be presented from a plurality of relevant items. For example, "at least one of the first, second and third items" may mean not only the first, second or third item, respectively, but also all combinations of items that can be presented from two or more of the first, second and third items.

[0023] The features of the various examples of the present application may be partially or fully combined or combined with each other, and may be technically interlocked and driven in various ways, and each example may be implemented independently of the other, or may be implemented together in a related relationship.

[0024] Hereinafter, examples of display devices according to the present application will be described in detail with reference to the accompanying drawings. In attaching reference numerals to components in each drawing, the same components may have the same reference numerals as much as possible even if they are displayed in different drawings. In addition, the scale of the configurations shown in the accompanying drawings may be different from the actual scale for convenience of explanation, and therefore are not limited to the scale shown in the drawings.

[0025] The inventors of the present application have recognized the problems of a general display device and conducted various experiments to direct the direction of sound toward the front side of the display panel when a user positioned in front of the display panel watches an image. This can improve sound quality. Therefore, through various experiments, the inventors of the present application have invented a display device that can improve sound quality by generating sound that travels toward a forward area in front of the display panel.

[0026] FIG. 1 shows a display device according to the present application.

[0027] Referring to FIG. 1, the display apparatus according to the present application can output sounds (S1, S2, S3) by vibration of a display module 100 configured to display an image. For example, in a display device, the display module 100 can generate sounds (S1, S2, S3) by vibrating with a vibration generating device (or a sound generating device). Most of the sounds (S1, S2, S3) generated by the vibration of the display module 100 can be directly output toward the front of the screen (FD) of the display apparatus, and the remaining sound (S3) of the sounds (S1, S2, S3) can be output to the side of the display apparatus and proceed toward the front of the screen (FD). Therefore, the display apparatus according to the embodiment of the present application can transmit sounds (S1, S2) accurately by using the display module 100 as a diaphragm for generating sounds and outputting sounds (S1, S2) to the front of the screen (FD) of the display module 100, thereby enabling accurate sound transmission, improving sound quality, and enhancing the immersive feeling of the viewer.

[0028] Fig. 2 is a diagram showing a vibration generating module disposed on the rear cover of the display device shown in Fig. 1. Fig. 3 is a schematic cross-sectional view of line II' shown in Fig. 1. Fig. 4 is an enlarged view of part 'A' shown in Fig. 3.

[0029] 2 to 4, a display device according to an embodiment of the present application may include a display module 100, a panel guide 200, a rear cover 300, a first vibration generating module 400, and a second vibration generating module 500.

[0030] The display module 100 may be, but is not limited to, a liquid crystal display module. For example, the display module 100 may be a display module such as a light-emitting display module, an electrophoretic display module, a micro light-emitting diode display module, an electrowetting display module, or a quantum dot light-emitting display module.

[0031] The rear surface (or back face) of the display module 100 may include a middle portion (CP) and an end portion (or peripheral portion) (or edge or edge portion) (EP). For example, the rear surface (or back or underside) of the display module 100 may be divided into a middle portion (CP) and an end portion (or peripheral portion) (EP) that is parallel (or aligned) with the middle portion (CP) therebetween.

[0032] The middle portion (CP) of the display module 100 may be divided into a first middle portion (C1) and a second middle portion (C2). For example, the first middle portion (C1) may be the left portion (or the left middle portion) of the middle portion (CP), and the second middle portion (C2) may be the right portion (or the right middle portion) of the middle portion (CP). The first middle portion (C1) and the second middle portion (C2) may be symmetrical about the middle line (CL) of the display module 100 based on the first direction (X) (or the horizontal direction) of the display module 100.

[0033] The display module 100 according to an embodiment of the present invention may include a display panel 110 and a backlight unit 130 .

[0034] The display panel 110 may be configured to display an image using light emitted from the backlight unit 130. The display panel 110 may also function as a diaphragm that vibrates due to the vibration (or drive) of the first and second vibration generating modules 400 and 500 and outputs sounds (S1, S2) to the front (FD). For example, the display panel 110 may output a first sound (S1) in a first range band due to the vibration of the first vibration generating module 400 and a second sound (S2) in the first and second range bands due to the vibration of the second vibration generating module 500 to the front (FD) simultaneously or sequentially. The first range band may be different from the second range band. A first sound (S1) in a first frequency range band may be output to the front (FD) at a middle portion (CP) of the display panel 110, and a second sound (S2) in a second frequency range band that is higher than the first sound (S1) in the first frequency range band may be output to the front (FD) from an edge portion (or peripheral portion) (or edge or near edge) (EP) of the display panel 110.

[0035] The display panel 110 according to an embodiment may include an upper substrate 111 , a lower substrate 113 , a lower polarizing member 115 , and an upper polarizing member 117 .

[0036] The upper substrate 111 may be a first substrate or a thin film transistor array substrate, and may include a pixel array (or a display unit) having a plurality of pixels formed in pixel regions intersected by a plurality of gate lines and a plurality of data lines. Each of the plurality of pixels may include a thin film transistor connected to the gate line and the data line, a pixel electrode connected to the thin film transistor, and a common electrode formed adjacent to the pixel electrode and supplied with a common voltage.

[0037] The upper substrate 111 may further include a pad portion provided at the first end (or periphery) (or first non-display portion) (or edge or near the edge), and a gate driving circuit provided at the second end (or periphery) (or second non-display portion) (or edge or near the edge).

[0038] The pad unit may supply an externally supplied signal to the pixel array and the gate driving circuit. For example, the pad unit may include a plurality of data pads connected to a plurality of data lines via a plurality of data link lines, and a plurality of gate input pads connected to the gate driving circuit via a gate control signal line. As an example, a first end of the upper substrate 111 including the pad unit may protrude from a side surface corresponding to a first end of the lower substrate 113, and the pad unit may be exposed in a rear direction toward the rear cover 300. For example, the size of the upper substrate 111 may be larger than the size of the lower substrate 113, but is not limited thereto.

[0039] The gate driving circuit according to an embodiment can be built in (or integrated) at the second end of the upper substrate 111 so as to connect one-to-one with the plurality of gate lines. For example, the gate driving circuit can be a shift register including transistors formed by the same process as the thin film transistors provided in the pixel region.

[0040] According to another embodiment, the gate driving circuit may not be built in the upper substrate 111, but may be implemented in the form of an integrated circuit and included in the panel driving circuit.

[0041] The lower substrate 113 is a color filter array substrate and may include a pixel definition pattern capable of defining an opening region overlapping each pixel region formed in the upper substrate 111, and a color filter layer formed in the opening region. According to an embodiment, the lower substrate 113 may have a size smaller than that of the upper substrate 111, but is not limited thereto. For example, the lower substrate 113 may overlap with the remaining portion of the upper substrate 111 except for a first end. The lower substrate 113 may be bonded to the remaining portion of the upper substrate 111 except for a first end, sandwiching a liquid crystal layer therebetween, using a sealant.

[0042] The liquid crystal layer is interposed between the upper substrate 111 and the lower substrate 113, and may be made of liquid crystal whose alignment direction changes according to an electric field formed by a data voltage and a common voltage applied to a pixel electrode for each pixel.

[0043] The lower polarizing member 115 is attached to the lower surface of the lower substrate 113 and can polarize the light incident from the backlight unit 130 and traveling to the liquid crystal layer.

[0044] The upper polarizing member 117 is attached to the upper surface of the upper substrate 111 and can polarize light that passes through the upper substrate 111 and is emitted to the outside.

[0045] The display panel 110 according to an embodiment can display an image by light passing through the liquid crystal layer by driving the liquid crystal layer with an electric field formed for each pixel by a data voltage and a common voltage applied to each pixel.

[0046] In the display panel 110 according to the embodiment, the upper substrate 111 made of a thin film transistor array substrate constitutes an image display surface, so that the entire front surface can be exposed to the outside without being blocked by a separate mechanism.

[0047] For example, in the display panel 110 according to another embodiment, the upper substrate 111 may be a color filter array substrate, and the lower substrate 113 may be a thin film transistor array substrate. For example, the display panel 110 according to another embodiment may have a shape obtained by inverting the display panel 110 according to the one embodiment. In another embodiment, the pad portion of the display panel 110 according to another embodiment may be covered by a separate mechanism or structure.

[0048] The display module 100 according to an embodiment may further include a buffer member 150 .

[0049] The buffer member 150 may surround the side of the display panel 110 and cover each side and each corner of the display panel 110. The buffer member 150 may protect the side of the display panel 110 from external impact and reduce or prevent light leakage from the side of the display panel 110. The buffer member 150 may be made of a silicone-based or ultraviolet (UV) curing sealant (or resin). In one embodiment, the buffer member 150 may be made of an ultraviolet (UV) curing sealant in consideration of the process tact time. The buffer member 150 may also be colored (e.g., blue, red, cyan, or black), but is not limited thereto. For example, the buffer member 150 may be made of a colored resin or a light blocking resin to prevent light leakage from the side.

[0050] According to an embodiment, a portion of the upper surface of the buffer member 150 may be covered by the upper polarizing member 117. For example, the upper polarizing member 117 may include an extension portion that is extended from a side surface corresponding to an outer side surface of the upper substrate 111 to cover a portion of the front surface of the buffer member 150 and is attached to a portion of the front surface of the buffer member 150. A joint surface (or an attachment surface) between the buffer member 150 and the upper substrate 111 (or a boundary portion between the buffer member 150 and the upper substrate 111) may be concealed by the extension portion of the upper polarizing member 117 and may not be exposed to the front of the display device where a viewer is positioned. In an example where the buffer member 150 is not formed, a side surface of the display panel 110 is exposed to the front (FD) of the display device without a separate mechanism, so that a light leakage phenomenon from the side of the display panel 110 may occur. Therefore, the buffer member 150 may be configured to prevent or reduce light leakage from the sides of the display panel 110 in a display device having a structure in which the entire front surface of the display panel 110 is exposed to the forward direction (FD) in order to reduce or minimize the bezel width of the display device as much as possible.

[0051] The backlight unit 130 is disposed on the rear surface of the display panel 110 and can irradiate the rear surface of the display panel 110 with light.

[0052] In the embodiment of the present application, the backlight unit 130 includes a light guide plate 131 , a light source unit, a reflective sheet 133 , and an optical sheet unit 135 .

[0053] The light guide plate 131 is disposed on the rear cover 300 so as to overlap the display panel 110, and includes a light incident surface provided on at least one side wall. The light guide plate 131 may include a light-transmitting plastic or glass material. The light guide plate 131 guides (or outputs) light incident from a light source through the light incident surface toward the display panel 110. For example, the light guide plate 131 may be expressed as a light guide member or a flat light source, but is not limited thereto.

[0054] The light source unit irradiates light onto a light incident surface provided on the light guide plate 131. The light source unit may be disposed on the rear cover 300 so as to overlap with a first end of the display panel 110. The light source unit according to an embodiment may include a plurality of light emitting diode elements (LEDs) mounted on a light source printed circuit board (PCB) to irradiate light onto the light incident surface of the light guide plate 131.

[0055] The reflective sheet 133 may be disposed on the rear cover 300 so as to cover the rear surface of the light guide plate 131. The reflective sheet 133 may reflect the light incident from the light guide plate 131 toward the light guide plate 131, thereby reducing or minimizing the loss of light as much as possible.

[0056] The optical sheet unit 135 is disposed on the front surface of the light guide plate 131 to improve the brightness characteristics of the light output from the light guide plate 131. The optical sheet unit 135 according to an example may include a lower diffusion sheet, a lower prism sheet, and an upper prism sheet, but is not limited thereto, and may be formed of a laminate of one or more of a diffusion sheet, a prism sheet, a dual brightness enhancement film, and a lenticular sheet, or may be formed of a single composite sheet having a function of diffusing and collecting light.

[0057] The panel guide 200 can support an edge portion (EP) on the rear side of the display panel 110. The panel guide 200 can be supported or stored in the rear cover 300 so as to overlap with the edge portion (EP) on the rear side of the display panel 110. The panel guide 200 can be disposed under the edge portion (EP) on the rear side of the display panel 110 so as not to protrude outside of each side of the display panel 110.

[0058] The panel guide 200 may include a panel support portion 210 and a guide side wall 230. For example, the panel guide 200 may have a cross-sectional structure in the shape of a square or a square depending on the coupling or connecting structure of the panel support portion 210 and the guide side wall 230.

[0059] The panel supporter 210 may be coupled (or connected) to an edge portion (EP) of the rear surface of the display panel 110 and supported by the rear cover 300. For example, the panel supporter 210 may have a rectangular band shape having an opening (or hole or hole portion) overlapping with a remaining middle portion (CP) of the display panel 110 excluding the edge portion (EP) of the rear surface, but is not limited to this shape. The panel supporter 210 may have a size equal to or smaller than the size of the display panel 110 so as not to protrude outside each side of the display panel 110. For example, the hole of the panel supporter 210 may have a size equal to or larger than the pixel array (or display unit) provided on the display panel 110.

[0060] The panel support part 210 may be in direct contact with the top surface of the backlight unit 130 , for example, the top surface of the optical sheet part 135 , or may be spaced a certain distance from the top surface of the optical sheet part 135 .

[0061] The guide sidewall 230 is connected to (or integrated with) the panel support 210 and wraps around the side of the rear cover 300. For example, the guide sidewall 230 may bend from the panel support 210 toward the side of the rear cover 300 to surround the side of the rear cover 300 or may be surrounded by the side of the rear cover 300.

[0062] The panel guide 200 may be made of, but is not limited to, a plastic material, a metal material, or a mixture of a plastic material and a metal material. For example, the panel guide 200 may also serve as a vibration transmitting member that transmits sound vibrations generated by the second vibration generating module 500 to the edge portion (EP) of the display panel 110. Therefore, the panel guide 200 can transmit sound vibrations generated by the second vibration generating module 500 to the display panel 110 without loss while maintaining the rigidity of the display panel 110. For example, the panel guide 200 may include, but is not limited to, a metal material in order to transmit sound vibrations generated by the second vibration generating module 500 to the display panel 110 while maintaining the rigidity of the display panel 110.

[0063] The panel guide 200 may be coupled or connected to a rear edge portion (EP) of the display panel 110 via a first coupling member (or a first connecting member) 250 .

[0064] The first connecting member 250 (or panel bonding member or first connecting member) is interposed between the rear end portion (EP) of the display panel 110 and the panel support portion 210 of the panel guide 200 to connect the display panel 110 to the panel guide 200. The first connecting member 250 according to an embodiment may include, but is not limited to, an acrylic or urethane adhesive member. For example, the first connecting member 250 may include, but is not limited to, an acrylic adhesive member having relatively excellent adhesive strength and high hardness so that vibration of the panel guide 200 can be well transmitted to the display panel 110. For example, the first connecting member 250 may include a double-sided foam adhesive pad having an acrylic adhesive layer or an acrylic adhesive resin hardened layer.

[0065] According to an embodiment, the front surface of the first connecting member 250 may be bonded (or connected) to the lower substrate 113 or the lower polarizing member 115 of the display panel 110. For example, the front surface of the first connecting member 250 may be directly bonded (or connected) to the rear edge portion (EP) of the lower substrate 113 to improve adhesion to the display panel 110. The first connecting member 250 is attached to the rear edge portion (EP) of the lower substrate 113 and surrounds the side of the lower polarizing member 115, thereby preventing light leakage from the side of the lower polarizing member 115.

[0066] The first connecting member 250 may provide a sound transmission space (STS) between the display panel 110 and the panel guide 200 to have a certain thickness (or height). The first connecting member 250 according to an embodiment may be formed in a four-sided closed type or closed loop shape on the panel support part 210 of the panel guide 200, but is not limited thereto. For example, the first connecting member 250 provides a sealed sound transmission space (STS) between the rearmost surface of the display panel 110 and the uppermost surface of the backlight unit 130, which face each other across the hole of the panel guide 200, thereby preventing, reducing or minimizing leakage (or loss) of sound pressure transmitted to the sound transmission space (STS). The sound transmission space (STS) may serve as a sound pressure generation space where sound pressure is generated by the vibration of the backlight unit 130, or a panel vibration space that smooths the vibration of the display panel 110 due to sound pressure.

[0067] The rear cover 300 may be configured to support the panel guide 200 and cover the rear surface of the display module 100. The rear cover 300 may also be configured to support the first and second vibration generating modules 400 and 500. The rear cover 300 may also function as a diaphragm and may include a metal material or a metal alloy material. For example, the rear cover 300 may be made of any one of an aluminum (Al) material, a magnesium (Mg) alloy material, a magnesium lithium (Li) alloy material, and an aluminum (Al) alloy material, but is not limited thereto.

[0068] The rear cover 300 may further include a rear cover portion 310 configured to support the rear of the display module 100, and a side cover portion 330 connected to and / or integrated with an end portion (EP) of the rear cover portion 310 to support the panel guide 200.

[0069] The rear cover part 310 is disposed to cover the rear surface of the display module 100 and can support the display module 100. The rear cover part 310 has a plate-like structure and can support the backlight unit 130 of the display module 100 and each of the first vibration generating module 400 and the second vibration generating module 500. For example, the rear cover part 310 can also play a role of transmitting sound vibrations generated by vibrations of the first vibration generating module 400 and the second vibration generating module 500 to the reflection sheet 133 of the backlight unit 130 by directly contacting the rear surface of the reflection sheet 133.

[0070] The rear cover portion 310 may include a middle area (MA) that corresponds to (or overlaps with) the middle portion (CP) of the display module 100 and an end area (EA) that corresponds to (or overlaps with) the end portion (EP) of the display module 100.

[0071] The middle area (MA) (or first cover area) of the rear cover part 310 according to an embodiment of the present application may include a first middle area (MA1) (or left middle area) corresponding to (or overlapping) the first middle part (C1) of the display module 100 and a second middle area (MA2) (or right middle area) corresponding to (or overlapping) the second middle part (C2) of the display module 100 based on the middle line (CL) of the display module 100. Each of the first middle area (MA1) and the second middle area (MA2) of the rear cover part 310 may include a first support area (SA1) for supporting the first vibration generating module 400. For example, the center of the first support area (SA1) may be located on the horizontal line (HL) (or mid-horizontal line) of the display module 100 based on the second direction (Y) (or vertical direction), or may be located above or below the horizontal line (HL) along the second direction (Y).

[0072] The end area (EA) (or the second cover area) of the rear cover part 310 may include a second support area (SA2) for supporting the second vibration generating module 500. For example, the center of the second support area (SA2) may be located on the horizontal line (HL) (or the middle horizontal line) of the display module 100 based on the second direction (Y). The center of the first support area (SA1) may be located on the horizontal line (HL) of the display module 100, like the center of the second support area (SA2), or may be spaced upward or downward from the horizontal line (HL) along the second direction (Y).

[0073] 4 shows an example in which the rear cover part 310 is in close contact with the backlight unit 130, but is not limited thereto. For example, the rear cover part 310 may be spaced apart from the backlight unit 130 by a predetermined space, and an air layer may be formed in the space. According to an embodiment, the space between the rear cover part 310 and the backlight unit 130 may be disposed in a central portion (CP) of the display module 100.

[0074] The rear cover part 310 according to the embodiment of the present application may include a rear cover hole 311 (or a first rear cover hole). The rear cover hole 311 may be spaced apart from a portion of the first vibration generating module 400 and may be located in a middle area (MA) of the rear cover part 310 corresponding to a middle part (CP) of the display module 100. The rear cover hole 311 may be formed to penetrate the rear cover part 310 along a thickness direction (Z) of the rear cover part 310 in the middle area (MA) of the rear cover part 310. For example, the rear cover hole 311 may be disposed between the first support area (SA1) and the second support area (SA2) within the area of ​​the rear cover part 310. The rear cover hole 311 may have a circular shape, but is not limited thereto. The rear cover hole 311 may be expressed as an opening hole, a hole part, a duct hole, a resonating hole, or the like, but is not limited thereto.

[0075] The rear cover hole 311, the rear cover part 310, the first vibration generating module 400, and the system rear cover 600 according to the present application form a Helmholtz resonator, which can reduce noise characteristics for low frequencies. A detailed description of the Helmholtz resonator formed by the rear cover hole 311, the rear cover part 310, the first vibration generating module 400, and the system rear cover 600 will be given later with reference to FIGS. 9 and 10.

[0076] In addition, according to an embodiment of the present application, the rear cover 300 may further include a first hole 313 and a second hole 315 .

[0077] The first hole 313 (or the first through hole or the second rear cover hole) is disposed in a first rear region of the rear cover 300 overlapping with the first vibration generating module 400, and may be covered by the reflective sheet 133 of the backlight unit 130. For example, the first hole 313 may be provided in the middle region (MA) of the rear cover part 310. The first hole 313 may be formed to penetrate the first support region (SA1) of the rear cover part 310 in the middle region (MA) of the rear cover part 310 along the thickness direction (Z) of the rear cover part 310.

[0078] The first hole 313 may provide a first gap between the backlight unit 130 and the first vibration generating module 400. For example, the first gap may be expressed as a vibration space caused by driving the first vibration generating module 400, a sound pressure space (or a resonating part or a resonance part) where sound pressure is generated by the vibration of the first vibration generating module 400, or a sound wave propagation path (or an acoustic energy incident part) where sound waves generated by the vibration of the first vibration generating module 400 are directly transmitted to the display module 100, but is not limited thereto.

[0079] The size (or width) of the first hole 313 according to an embodiment may be smaller than the size of the first vibration generating module 400. If the overall size (or overall width) of the first hole 313 is larger than the overall size of the first vibration generating module 400, the first vibration generating module 400 cannot be disposed on the rear cover part 310 without using a separate mechanism because the first vibration generating module 400 is inserted (or penetrated or housed) in the first hole 313. Therefore, if the overall size of the first hole 313 is smaller than the overall size of the first vibration generating module 400, the first vibration generating module 400 can be disposed on the rear cover part 310 so as to overlap with the first hole 313 without using a separate mechanism. For example, the first hole 313 according to an embodiment may have the same shape as the first vibration generating module 400, or a square shape (e.g., a quadrilateral shape) or a circular shape, but is not limited thereto.

[0080] The second hole 315 (or the second through hole or the third rear cover hole) may be disposed in a second rear region of the rear cover 300 overlapping with the second vibration generating module 500 and may be covered by the reflective sheet 133 of the backlight unit 130. For example, the second hole 315 may be provided in an edge region (EA) of the rear cover part 310. The second hole 315 may be formed to penetrate a second support region (SA2) of the rear cover part 310 in the edge region (EA) of the rear cover part 310 along a thickness direction (Z) of the rear cover part 310.

[0081] The second hole 315 may provide a second gap space between the backlight unit 130 and the second vibration generating module 500. For example, the second gap space may be expressed as a vibration space caused by driving the second vibration generating module 500, a sound pressure space (or a resonating part or a resonance part) where sound pressure is generated by the vibration of the second vibration generating module 500, or a sound wave propagation path (or a sound energy incident part) where sound waves generated by the vibration of the second vibration generating module 500 are directly transmitted to the display module 100, but is not limited thereto.

[0082] The size (or width) of the second hole 315 according to an embodiment may be smaller than the size of the second vibration generating module 500. If the overall size (or overall width) of the second hole 315 is larger than the overall size of the second vibration generating module 500, the second vibration generating module 500 cannot be disposed on the rear cover part 310 so as to overlap with the second hole 315 without using a separate mechanism because the second vibration generating module 500 is inserted (or penetrated or housed) in the second hole 315. Therefore, if the overall size of the second hole 315 is smaller than the overall size of the second vibration generating module 500, the second vibration generating module 500 can be disposed on the rear cover part 310 so as to overlap with the second hole 315 without using a separate mechanism. For example, the second hole 315 according to an embodiment may have the same shape as the second vibration generating module 500, or a square or circular shape, but is not limited thereto.

[0083] The side cover part 330 may be bent from an end of the rear cover part 310 to support the panel guide 200. The side cover part 330 provides a backlight accommodating space (or space) on the rear cover part 310 and surrounds the side of the backlight unit 130 accommodated (or supported) in the backlight accommodating space. The side cover part 330 may also serve to transmit sound vibrations generated in the rear cover part 310 by the second vibration generating module 500 to the panel guide 200.

[0084] The rear cover 300 may further include a reinforcing portion 350. The reinforcing portion 350 may be a rigidity reinforcing portion since it can reinforce the rigidity of the rear cover 300, but is not limited thereto.

[0085] The reinforcing portion 350 may be formed in an area (or a connecting area) where the rear cover portion 310 and the side cover portion 330 intersect. As an example, the reinforcing portion 350 may be formed along an end area (or peripheral area) (EA) of the rear cover portion 310. For example, the reinforcing portion 350 may protrude toward the rear direction from an end of the rear cover portion 310 to have an inclined slope. When the rear cover 300 includes the reinforcing portion 350, the side cover portion 330 may be connected and / or integrated with an end portion of the reinforcing portion 350.

[0086] The first vibration generating module 400 is disposed in a first rear region of the rear cover 300 and can vibrate a first region of the display module 100. For example, the first rear region of the rear cover 300 can overlap with a middle portion (CP) or an end portion (EP) of the display module 100, and the first region of the display module 100 can be the middle portion (CP) or the end portion (EP).

[0087] The first vibration generating module 400 according to an example of the present application is disposed in the middle area (MA) of the rear cover 300 and can vibrate the middle part (CP) of the display module 100. The first vibration generating module 400 can generate sound pressure between the display module 100 and the rear cover 300 at the middle part (CP) of the display module 100. The first vibration generating module 400 can generate sound pressure between the display module 100 and the rear cover 300, and vibrate the middle part (CP) of the display module 100 by the sound pressure, thereby generating a first sound (S1) of a first sound range band at the middle part (CP) of the display module 100. The first sound (S1) of the first sound range band according to an example may have a frequency of a bass band. For example, the bass band may be 200 Hz or less, but is not necessarily limited thereto, and may be 3 kHz or less.

[0088] The first vibration generating module 400 according to an embodiment may be coupled or disposed in the middle area (MA) of the rear cover part 310 of the rear cover 300. For example, the first vibration generating module 400 may be coupled or disposed in the first support area (SA1) of the middle area (MA) of the rear cover part 310. Thus, the first vibration generating module 400 generates sound pressure by vibrating the middle area (MA) of the rear cover part 310 in response to an externally input sound signal (or voice signal), and may vibrate the middle part (CP) of the display module 100 through the sound pressure to generate a first sound (S1) of a first sound range. As an example, the first vibration generating module 400 may include a sound actuator or a sound exciter, but is not limited thereto, and may be embodied as a sound generating device using a coil (or voice coil) and a magnet.

[0089] According to one embodiment, the first vibration generating module 400 may include a first sound generating unit 410 and a second sound generating unit 430 .

[0090] The first sound-generating unit 410 may vibrate a first middle portion (C1) of the central portion (CP) of the display module 100 to output a first sound (S1) in a first sound range to the front (FD) of the display panel 110. The first sound-generating unit 410 may be disposed in a first support area (SA1) of a first middle area (MA1) of the central area (MA) of the rear cover part 310. For example, the first sound-generating unit 410 may be disposed in or coupled to the rear cover part 310 so as to cover a first hole 313 formed in the first support area (SA1) of the first middle area (MA1) of the rear cover part 310.

[0091] According to an embodiment, the first sound generating unit 410 vibrates the first middle area (MA1) of the rear cover part 310 in response to an acoustic signal to generate sound pressure inside the first hole 313 (or the first gap), thereby vibrating the first middle part (C1) of the display module 100 to generate a first sound (S1) in a first sound range. For example, when the first sound generating unit 410 vibrates according to an acoustic signal, sound pressure is generated inside the first hole 313 due to the vibration of the first middle area (MA1) of the rear cover part 310 caused by the vibration of the first sound generating unit 410, sound pressure is generated in the sound transmission space (STS) due to the vibration of the backlight unit 130 caused by the sound pressure, and the first sound (S1) in the first sound range generated by the vibration of the first middle part (C1) of the display panel 110 due to the sound pressure generated in the sound transmission space (STS) may be output to the front (FD) of the display panel 110. Therefore, the sound waves generated by the vibration of the first sound generating unit 410 are directly transmitted (or propagated) to the display module 100 through the first hole 313, thereby improving the sound pressure characteristics and sound quality of the first sound (S1).

[0092] The second sound generating unit 430 may vibrate a second middle portion (C2) of the middle portion (CP) of the display module 100 to output a first sound (S1) of a first sound range to the front (FD) of the display panel 110. The second sound generating unit 430 may be disposed in a first support area (SA1) of a second middle area (MA2) of the middle area (MA) of the rear cover part 310. As an example, the second sound generating unit 430 may be disposed on or coupled to the rear cover part 310 so as to cover a first hole 313 formed in the first support area (SA1) of the second middle area (MA2) of the rear cover part 310.

[0093] According to an embodiment, the second sound generating unit 430 vibrates the second middle area (MA2) of the rear cover part 310 in response to an acoustic signal to generate sound pressure inside the first hole 313 (or the first gap), thereby vibrating the second middle part (C2) of the display module 100 to generate a first sound (S1) in a first sound range. For example, when the second sound generating unit 430 vibrates according to an acoustic signal, sound pressure is generated inside the first hole 313 due to the vibration of the second middle area (MA2) of the rear cover part 310 caused by the vibration of the second sound generating unit 430, sound pressure is generated in the sound transmission space (STS) due to the vibration of the backlight unit 130 caused by the sound pressure, and the first sound (S1) in the first sound range generated by the vibration of the second middle part (C2) of the display panel 110 due to the sound pressure generated in the sound transmission space (STS) may be output to the front (FD) of the display panel 110. Therefore, the sound waves generated by the vibration of the second sound generating unit 430 are directly transmitted (or propagated) to the display module 100 through the first hole 313, thereby improving the sound pressure characteristics and sound quality of the first sound (S1).

[0094] According to an embodiment, the positions of the first sound generating unit 410 and the second sound generating unit 430 may be adjusted to realize a stereophonic sound or to harmonize with the sound produced by the vibration of the first sound generating unit 410 and the second sound generating unit 430. For example, the positions of the first and second sound generating units 410, 430 may be symmetrical or asymmetrical with respect to a midline (CL) of the display module 100 based on a first direction (X) (or horizontal direction) of the display module 100.

[0095] The first vibration generating module 400 may include only one sound generating unit 410 arranged in the center of the rear cover part 310 so that the low-pitched sound (S1) generated by the vibration of the display panel 110 corresponding to the vibration of the rear cover part 310 can pass through the air and be transmitted directly to the listener, but the embodiment is not necessarily limited thereto.

[0096] The second vibration generating module 500 is disposed in a second rear region of the rear cover 300 and can vibrate the second region of the display module 100. For example, the second rear region of the rear cover 300 may be a portion of the middle part (CP) and the end part (EP) of the display module 100 excluding the first rear region, and the second region of the display module 100 may be a portion of the middle part (CP) and the end part (EP) of the display module 100 excluding the first region. For example, the second rear region of the rear cover 300 may be a portion of the middle part (CP) and the end part (EP) of the display module 100 excluding the region overlapping with the first rear region, and the second region of the display module 100 may be a portion of the middle part (CP) and the end part (EP) of the display module 100 excluding the first region.

[0097] The second vibration generating module 500 is disposed in the edge area (EA) of the rear cover 300 and can vibrate the edge portion (or peripheral portion) (EP) of the display module 100. The second vibration generating module 500 can generate sound vibrations in the edge portion (EP) of the display module 100. The second vibration generating module 500 can generate a first sound (S1) in a first frequency band generated in the central portion (CP) of the display module 100 and a second sound (S2) in a second frequency band in the edge portion (EP) of the display module 100. The second sound (S2) in the second frequency band according to an example can have a frequency in a mid-high frequency band or a high frequency band. For example, the mid frequency band can be 200Hz to 3kHz, but is not necessarily limited thereto, and can be 3kHz to 5kHz. The high frequency band can be 3kHz or more, but is not necessarily limited thereto, and can be 5kHz or more.

[0098] The second vibration generating module 500 according to an embodiment may be coupled or disposed in an edge area (EA) of the rear cover part 310 of the rear cover 300. For example, the second vibration generating module 500 may be coupled or disposed in a second support area (SA2) in the edge area (EA) of the rear cover part 310. Thus, the second vibration generating module 500 generates sound vibrations by vibrating the edge area (EA) of the rear cover part 310 in response to an externally input sound signal (or voice signal), and may vibrate the edge part (EP) of the display module 100 through the sound vibrations to generate a second sound (S2) in a second sound range. The second vibration generating module 500 may include a piezoelectric element or a piezoelectric material having a piezoelectric effect (or an inverse piezoelectric characteristic).

[0099] The second vibration generating module 500 may include a first piezoelectric vibration unit 510 and a second piezoelectric vibration unit 530 .

[0100] The first piezoelectric vibration unit 510 may vibrate a first end portion (EP1) (or a left end portion or a portion close to the left end) of the end portion (EP) of the display module 100 to output a second sound (S2) in a second sound range to the front (FD) of the display panel 110. The first piezoelectric vibration unit 510 may be disposed in a second support area (SA2) in a first end area (or a left end area or a portion close to the left end) (EA1) of the end area (EA) of the rear cover part 310. For example, the first piezoelectric vibration unit 510 may be disposed in or coupled to the rear cover part 310 so as to cover a second hole 315 formed in the second support area (SA2) of the first end area (EA1) of the rear cover part 310.

[0101] According to an embodiment, the first piezoelectric vibrating unit 510 vibrates the first end area (EA1) of the rear cover part 310 in response to an acoustic signal to acoustically vibrate the first end portion (EP1) of the display panel 110, thereby generating a second sound (S2) in a second frequency range from the first end portion (EP1) of the display panel 110. For example, when the first piezoelectric vibrating unit 510 vibrates according to an acoustic signal, the acoustic vibration generated in the first end area (EA1) of the rear cover part 310 due to the vibration of the first piezoelectric vibrating unit 510 is transmitted to the first end portion (EP1) of the display panel 110 via the side cover part 330 of the rear cover 300 and the panel guide 200, and the sound (S2) in the second frequency range generated by the vibration of the first end portion (EP1) of the display panel 110 due to the acoustic vibration transmitted via the panel guide 200 can be output to the front (FD) of the display panel 110. Therefore, the sound waves generated by the vibration of the first piezoelectric vibration unit 510 are directly transmitted (or propagated) to the first end portion (EP1) of the display module 100 through the second hole 315, thereby improving the sound pressure characteristics and sound quality of the second sound (S2), and the sound pressure characteristics and sound quality of the second sound (S2) can be further improved by reducing the vibration of the first end area (EA1) of the rear cover part 310 due to the vibration of the first piezoelectric vibration unit 510.

[0102] According to an embodiment, the first piezoelectric vibration unit 510 may be disposed adjacent to the side cover portion 330 of the rear cover 300 so that a second high-pitched sound (S2) generated by sound vibration of the first end portion (EP1) of the display panel 110 corresponding to sound vibration of the first end region (EA1) of the rear cover portion 310 is directly transmitted to a listener. For example, the first piezoelectric vibration unit 510 may be disposed in the first end region (EA1) of the rear cover portion 310 so as to overlap with the panel support portion 210 of the panel guide 200 supporting the second end portion (EP1) of the display panel 110.

[0103] The first piezoelectric vibration unit 510 according to an example may be disposed on a horizontal line (or mid-horizontal line) (HL) of the rear cover part 310 based on the length direction (or vertical direction) of the rear cover part 310 in line with the second direction (Y). For example, the first sound generating unit 410 of the first vibration generating module 400 according to an example may be disposed on the same line as the first piezoelectric vibration unit 510 based on the second direction (Y) or may be disposed above or below the horizontal line (or mid-horizontal line) (HL) in line with the first direction (X). As an example, the center of the first sound generating unit 410 may be disposed on a horizontal line (or mid-horizontal line) (HL) extended from the center of the first piezoelectric vibration unit 510 in parallel with the first direction (X). As another example, the center of the first sound generating unit 410 may be disposed below or above the horizontal line (or mid-horizontal line) (HL) based on the second direction (Y). The center of the first sound generating unit 410 may be positioned below the horizontal line (or mid-horizontal line) (HL) rather than above the horizontal line (or mid-horizontal line) (HL) based on the second direction (Y) so that the first low-pitched sound (S1) generated by vibration of the first middle part (C1) of the middle part (CP) of the display module 100 is transmitted directly to the listener.

[0104] According to an embodiment, the first piezoelectric vibration unit 510 may include a first piezoelectric element 511 attached to the rear cover part 310 via a first adhesive member 513 .

[0105] The first piezoelectric element 511 may include a piezoelectric material layer having a piezoelectric effect.

[0106] The piezoelectric material layer may include a piezoelectric material that generates vibrations in response to an electric field. Piezoelectric materials have the characteristic that when pressure or twisting is applied to the crystal structure by an external force, a potential difference is generated due to dielectric polarization caused by the change in the relative positions of positive (+) ions and negative (-) ions, and vibrations are generated by the electric field caused by the opposite voltage.

[0107] The piezoelectric layer according to an embodiment may include a polymeric piezoelectric, a thin film piezoelectric, a composite piezoelectric, or a single crystal ceramic or polycrystalline ceramic piezoelectric. The polymeric piezoelectric according to an embodiment may include PVDF (polyvinylidene fluoride), P(VDF-TrFe) (poly(vinylidene fluoride-trifluoroethylene)), or P(VDF-TeFE) (poly(vinylidene fluoride-tetrafluoroethylene)). The thin film piezoelectric according to an embodiment may include ZnO, CdS, or AlN. The composite piezoelectric according to an embodiment may include PZT (lead zirconate titanate)-PVDF, PZT-silicon rubber, PZT-epoxy, PZT-foam polymer, or PZT-foam urethane. According to an embodiment, the single crystal ceramic piezoelectric material may include aluminum phosphate (e.g., berlinite, α-AlPO4), silicon dioxide (e.g., α-SiO2), lithium niobate (LiNbO3), terbium molydbate (Tb2(MoO4)3), lithium tetraborate (Li2B4O7), or ZnO. According to an embodiment, the polycrystalline ceramic piezoelectric material may include PZT, PT, PZT-complex perovskite, or barium titanate (BaTiO3).

[0108] According to one embodiment, the first piezoelectric element 511 may have a first length along a first direction (X) and a second length along a second direction (Y). For example, the first length of the first piezoelectric element 511 may be, but is not limited to, shorter than the second length and may be the same as or longer than the second length.

[0109] The first adhesive member 513 may be, but is not limited to, a double-sided tape or a natural curing adhesive. For example, the first adhesive member 513 may be a thermosetting adhesive or a photocuring adhesive. For example, the characteristics of the first piezoelectric element 511 may be deteriorated due to heat in the curing process of the first adhesive member 513.

[0110] According to an embodiment, the first piezoelectric vibration unit 510 may further include a first protective member 515 attached to the rear surface of the first piezoelectric element 511 .

[0111] The first protective member 515 may be formed to have a larger size than the first piezoelectric element 511 and may be attached to the rear surface of the first piezoelectric element 511. The first protective member 515 may prevent damage to the first piezoelectric element 511 due to electrical shock such as static electricity and / or physical shock. For example, the first piezoelectric element 511 may be damaged by static electricity generated in the display module 100 such as a panel driving circuit unit or flowing in from the outside, and may be damaged by physical contact with the display module 100 when the display module 100 is pressed. Thus, the first protective member 515 may be disposed between the display module 100 and the first piezoelectric element 511 to block static electricity transmitted to the first piezoelectric element 511 through the display module 100, thereby protecting the first piezoelectric element 511 from static electricity. Thus, the first protective member 515 may protect the first piezoelectric element 511 from static electricity and may also protect the first piezoelectric element 511 from physical shock applied to the first piezoelectric element 511. According to an embodiment, the first protective member 515 may include a single-sided insulating tape or an insulating single-sided foam tape having an adhesive layer attached to the rear surface of the first piezoelectric element 511. For example, the first protective member 515 may be a PET (polyethylene terephthalate) insulating tape or a PVC (polyvinyl chloride) insulating tape.

[0112] The second piezoelectric vibration unit 530 may vibrate a second end portion (EP2) (or a right end portion or a portion close to the right end) of the end portion (EP) of the display module 100 to output a second sound (S2) in a second sound range to the front (FD) of the display panel 110. The second piezoelectric vibration unit 530 may be disposed in a second support area (SA2) in a second end area (or a right end area or a portion close to the right end) (EA2) of the end area (EA) of the rear cover part 310. For example, the second piezoelectric vibration unit 530 may be disposed in or coupled to the rear cover part 310 so as to cover a second hole 315 formed in the second support area (SA2) of the second end area (EA2) of the rear cover part 310.

[0113] According to an embodiment, the second piezoelectric vibration unit 530 vibrates the second end area (EA2) of the rear cover part 310 in response to an acoustic signal to acoustically vibrate the second end part (EP2) of the display panel 110, thereby generating a second sound (S2) in a second sound range at the second end part (EP2) of the display panel 110. For example, when the second piezoelectric vibration unit 530 vibrates according to an acoustic signal, the acoustic vibration generated at the second end area (EA2) of the rear cover part 310 due to the vibration of the second piezoelectric vibration unit 530 is transmitted to the second end part (EP2) of the display panel 110 via the side cover part 330 of the rear cover 300 and the panel guide 200, and the sound (S2) in the second sound range generated by the vibration of the second end part (EP2) of the display panel 110 due to the acoustic vibration transmitted via the panel guide 200 can be output to the front (FD) of the display panel 110. Therefore, the sound waves generated by the vibration of the second piezoelectric vibration unit 530 are directly transmitted (or propagated) to the second end portion (EP2) of the display module 100 through the second hole 315, thereby improving the sound pressure characteristics and sound quality of the second sound (S2), and the sound pressure characteristics and sound quality of the second sound (S2) can be further improved by reducing the vibration of the second end area (EA2) of the rear cover part 310 due to the vibration of the second piezoelectric vibration unit 530.

[0114] According to one embodiment, the second piezoelectric vibrating unit 530 may be arranged in the second end area (EA2) of the rear cover part 310 symmetrically to the first piezoelectric vibrating unit 510 around the midline (CL) of the display module 100, or may be arranged at another position.

[0115] According to an embodiment, the positions of the first piezoelectric vibrating unit 510 and the second piezoelectric vibrating unit 530 may be set according to the harmony of sounds or the realization of stereophonic sounds caused by the vibrations of the first piezoelectric vibrating unit 510 and the second piezoelectric vibrating unit 530. For example, the respective positions of the first piezoelectric vibrating unit 510 and the second piezoelectric vibrating unit 530 may have a symmetrical structure or be arranged asymmetrically about the midline (CL) of the display module 100 based on the first direction (X) (or horizontal direction) of the display module 100.

[0116] According to an embodiment, the second piezoelectric vibration unit 530 may include a second piezoelectric element 531 attached to the rear cover part 310 via a second adhesive member 533 .

[0117] The second piezoelectric element 531 may include a piezoelectric material layer having a piezoelectric effect. The second piezoelectric element 531 has substantially the same configuration (or structure) as the first piezoelectric element 511 of the first piezoelectric vibration unit 510, and therefore, a duplicated description may be omitted.

[0118] The second adhesive member 533 may be, but is not limited to, a double-sided tape or a natural curing adhesive. The second adhesive member 533 may also be a thermosetting adhesive or a photocuring adhesive. However, for example, the characteristics of the second piezoelectric element 531 may be deteriorated due to heat in the curing process of the second adhesive member 533.

[0119] According to an embodiment, the second piezoelectric vibration unit 530 may further include a second protective member 535 attached to the rear surface of the second piezoelectric element 531 .

[0120] The second protective member 535 is formed to be larger than the second piezoelectric element 531, and may be attached to the rear surface of the second piezoelectric element 531. The second protective member 535 prevents damage to the second piezoelectric element 531 due to electrical shock such as static electricity and / or physical shock, and has substantially the same configuration (or structure) as the first protective member 515, so a duplicated description thereof will be omitted.

[0121] The display device according to the present application may further include a system back cover 600 disposed on the back of the back cover 300. The system back cover 600 may house the display module 100 to which the first and second vibration generating modules 400 and 500 are respectively coupled or connected, and may encase the sides of the display module 100. For example, the system back cover 600 may be expressed as, but is not limited to, a "set" cover, a "rear set" cover, an "outermost set" cover, a "product" cover, or an "outermost product" cover.

[0122] The system back cover 600 according to an embodiment may include a back structure 610 and a side structure 630. The back structure 610 is an outermost back mechanism located on the back of the display device, and may support (or house) the display module 100 and cover the back of the display module 100.

[0123] The side structure 630 is an outermost surface mechanism located on the side of the display device, and can be connected to and / or integrated with an edge of the rear structure 610 to cover the side of the display module 100 .

[0124] FIG. 5a is a diagram showing the system back cover shown in FIG. 1, and FIG. 5b is an enlarged view of a duct disposed on the system back cover of FIG. 5a.

[0125] Combining Figures 5a and 5b with Figure 4, in a system rear cover 600 according to one embodiment of the present application, the system rear structure 610 may further include a system rear cover box 611 that can accommodate the first vibration generating module 400 and the rear cover hole 311.

[0126] The system rear cover box 611 may be implemented on the inner surface of the system rear structure 610 so as to entirely surround the first vibration generating module 400 and the rear cover hole 311. The system rear cover box 611 may improve the sound pressure generated by the first vibration generating module 400 and amplify the first sound in the first sound range by providing a space (or a sealed space) between the rear cover part 310 and the system rear structure 610, thereby improving the characteristics of the first sound. The system rear cover box 611 may be combined (or connected) with the rear cover part 310 to define or seal the space around the first vibration generating module 400, thereby isolating the space around the first vibration generating module 400 from other spaces behind the rear cover part 310, and the surrounding space behind the first vibration generating module 400 may amplify the low-pitched sound generated by the vibration of the first vibration generating module 400.

[0127] The system rear cover box 611 may be combined or connected to the rear cover part 310 of the rear cover 300, and may be a partition that acoustically seals or separates a space in which the first vibration generating module 400 and the rear cover hole 311 are arranged. In this way, the present application can utilize the bass generated by the first vibration generating module 400, and amplify the sound pressure generated by the first vibration generating module 400 due to the resonance effect inside the system rear cover box 611. For example, the system rear cover box 611 may be expressed as an "acoustic box," "sound body," or "resonator," but is not limited thereto.

[0128] The display device according to an embodiment of the present application may further include a sealing member 700 for better sealing a joint portion (or a contact portion or a connection portion) between the system rear cover box 611 and the rear cover part 310, as shown in FIG.

[0129] The sealing member 700 can better acoustically seal the joint between the system rear cover box 611 and the rear cover part 310 .

[0130] The sealing member 700 according to one embodiment may be provided in a form that covers a joint (or connection) between the system rear cover box 611 and the rear cover unit 310. The sealing member 700 according to another embodiment may be inserted or housed at least partially in the joint between the system rear cover box 611 and the rear cover unit 310, thereby filling a gap that may be formed in the joint between the system rear cover box 611 and the rear cover unit 310, and further improving the sealing between the system rear cover box 611 and the rear cover unit 310. As a result, the space formed between the system rear cover box 611 and the rear cover unit 310 may provide an air layer that can improve the bass generated by the first vibration generating module 400, and may prevent or reduce the leakage (or loss) of sound pressure, or may minimize it as much as possible.

[0131] The sealing member 700 according to an embodiment may be made of a silicone-based or ultraviolet (UV) curing sealant (or resin), or may be made of an ultraviolet (UV) curing sealant, but is not limited thereto. For example, any material that can acoustically seal the joint between the system rear cover box 611 and the rear cover unit 310 may be used without limitation.

[0132] The system back cover 600 according to an embodiment of the present application may further include a system back cover duct 631 .

[0133] The system rear cover duct 631 can amplify bass sounds through the air flow generated by the vibration of the first vibration generating module 400. The system rear cover duct 631 can amplify bass sounds through the air flow generated when the first vibration generating module 400 vibrates in the reverse direction (or rear direction) and output the amplified bass sounds to the outside. For example, if the system rear cover duct 631 is not formed in the system rear cover 600, the air flows generated each time the first vibration generating module 400 vibrates in the reverse direction may be offset or lost. On the other hand, if the system rear cover duct 631 is formed in the system rear cover 600, the system rear cover duct 631 can smooth the air flows generated each time the first vibration generating module 400 vibrates in the reverse direction, and the air flows can be used to amplify bass sounds without being offset or lost. Therefore, the present application can improve or maximize the sound pressure characteristics of bass by using the air generated every time the first vibration generating module 400 vibrates in the opposite direction to amplify the bass by utilizing the system rear cover duct 631. For example, the system rear cover duct 631 can be expressed as an acoustic exhaust hole or a vent hole, but is not limited thereto.

[0134] According to an embodiment, the system rear cover duct 631 may be formed in at least a part of the side structure 630 of the system rear cover 600. As an example, the side structure 630 may have first to fourth side walls, and the system rear cover duct 631 may be formed in a first side wall (or a lower part) facing the ground among the first to fourth side walls of the side structure 630, but is not necessarily limited thereto. For example, the system rear cover duct 631 may be formed in at least one of the first to fourth side walls of the side structure 630 according to harmony with sounds generated by the first vibration generating module 400 and the second vibration generating module 500 or realization of stereophonic sounds.

[0135] FIG. 6 is a diagram showing the first and second sound generating units of the first vibration generating module shown in FIGS.

[0136] 3 and 6, each of the first and second sound generating units 410, 430 according to the present application may include a module frame 401, a bobbin 402, a magnet member 403, a coil 404, a center pole 405, and a damper 406. For example, in each of the first and second sound generating units 410, 430, the module frame 401 may be expressed as a fixed part fixed to the rear cover 300, and the bobbin 402, the magnet member 403, the coil 404, the center pole 405, and the damper 406 may be expressed as a vibration part for vibrating the display module 100, but is not necessarily limited thereto.

[0137] The module frame 401 may be supported by the rear cover portion 310. The module frame 401 may include a frame body 401a, an upper plate 401b, and a fixing bracket 401c.

[0138] The frame body 401a may be fixed to the rear cover portion 310. The frame body 401a may serve as a lower plate that supports the magnet member 403.

[0139] The upper plate 401b may protrude from the front end of the frame body 401a to have a cylindrical shape with a hollow portion. The frame body 401a and the upper plate 401b may be formed into one body having a "U" shape. For example, the frame body 401a and the upper plate 401b may be expressed by other terms such as "yoke" without being limited to such terms.

[0140] The fixing bracket 401c may protrude from a side surface of the upper plate 401b. The fixing bracket 401c may be fixed to the rear cover portion 310 by a second coupling member or a second connecting member, thereby fixing the module frame 401 to the rear cover portion 310.

[0141] The second coupling member or the second connecting member may be a screw or a bolt that passes through the fixing bracket 401c and fastens or connects to the rear cover part 310 of the rear cover 300. For example, a buffer ring may be interposed between the rear cover part 310 of the rear cover 300 and the fixing bracket 401c, and the buffer ring may prevent vibration of the rear cover part 310 from being transmitted to the module frame 401.

[0142] The bobbin 402 is disposed on the module frame 401 to vibrate the rear cover part 310 of the rear cover 300. The bobbin 402 may be circular having a hollow part 402a and may be combined or connected to the rear of the rear cover part 310. For example, the bobbin 402 may be embodied as a ring-shaped structure made of a material such as processed pulp or paper, aluminum, magnesium or alloys thereof, synthetic resin such as polypropylene, or polyamide-based fiber, but is not limited thereto. The bobbin 402 vibrates, for example, moves up and down, due to a magnetic force, to vibrate the rear cover 300 around the first hole 313 disposed in the rear cover 300.

[0143] The bobbin 402 according to an embodiment may have a circular or elliptical shape, but is not limited thereto. The oval-shaped bobbin 402 may include, but is not limited to, an elliptical shape, a rectangular shape with rounded corners, or a non-circular curved shape having a width different from its height. For example, the elliptical bobbin 402 may have a ratio of the diameter of the major axis to the diameter of the minor axis of 1.3:1 to 2:1. The elliptical bobbin 402 may improve the acoustics of the high-frequency range and may generate less heat due to vibration than the circular bobbin. Therefore, the elliptical bobbin 402 may have excellent heat dissipation characteristics.

[0144] The magnet member 403 may be disposed on the module frame 401 so as to be accommodated in the hollow portion 402a of the bobbin 402. The magnet member 403 may be a permanent magnet inserted into the hollow portion 402a of the bobbin 402. The magnet member 403 according to an embodiment may be embodied as a sintered magnet such as barium ferrite, and the material of the magnet member 403 may include, but is not limited to, one or more of ferric oxide (Fe2O3), barium carbonate (BaCO3), neodymium magnet, strontium ferrite with improved magnetic component, alloy cast magnet of aluminum (Al), nickel (Ni), and cobalt (Co), and the like. As another example, the neodymium magnet may be neodymium-iron-boron (Nd-Fe-B). The embodiments of the present application are not limited thereto.

[0145] The coil 404 is wound so as to surround the lower outer peripheral surface of the bobbin 402, and an acoustic signal (or a voice signal) is supplied from the outside. The coil 404 can rise and fall together with the bobbin 402. For example, the coil 404 can be expressed as a "voice coil" or the like, but is not limited thereto. When an acoustic signal (or a current) is applied to the coil 404, the entire bobbin 402 can vibrate, for example, reciprocate up and down, based on Fleming's left-hand rule based on the applied magnetic field formed around the coil 404 and the external magnetic field formed around the magnet member 403.

[0146] The center pole 405 is disposed on the magnet member 403 and can guide the vibration of the bobbin 402. For example, the center pole 405 can be surrounded by the bobbin 402 by being inserted or housed in the hollow portion 402a of the bobbin 402. For example, the center pole 405 can be expressed as an elevation guide or pole pieces, but is not limited thereto.

[0147] The dampers 406 may be disposed between the module frame 401 and the bobbin 402. The dampers 406 may be disposed between the frame body 401a of the module frame 401 and the upper outer circumferential surface of the bobbin 402. The dampers 406 may have a wrinkled structure between one end and the other end, and thus may contract and relax due to the vibration of the bobbin 402. These dampers 406 may limit the vibration distance (or vertical movement distance) of the bobbin 402 through a restoring force. For example, when the bobbin 402 vibrates more than a certain distance or less than a certain distance, the bobbin 402 may return to its original state by the restoring force of the dampers 406. For example, the dampers 406 may be expressed by other terms such as a spider, a suspension, or an edge, but are not limited thereto.

[0148] Each of the first and second sound generating units 410 and 430 according to an embodiment of the present application can be expressed as an inner type in which the magnet member 403 is inserted into the hollow portion 402 a of the bobbin 402 .

[0149] Each of the first and second sound-generating units 410 and 430 according to other embodiments of the present application may be expressed as an external type (or dynamic type) in which the magnet member 403 is disposed to surround the outside of the bobbin 402. For example, the external type sound-generating units 410 and 430 are similar to the internal type, except that the magnet member 403 is disposed between the frame body 401a and the upper plate 401b, and the center pole 405 is disposed on the lower plate 401a so as to be inserted into the hollow portion 402a of the bobbin 402. Therefore, a description thereof will be omitted.

[0150] Each of the first and second sound generating units 410 , 430 according to the present application may further include a bobbin protection member 407 disposed between the top of the bobbin 402 and the rear cover portion 310 of the rear cover 300 .

[0151] The bobbin protection member 407 is formed in a cylindrical structure having an opening that overlaps with the hollow portion 402a of the bobbin 402, and can be coupled or connected to the upper surface of the bobbin 402. The bobbin protection member 407 can protect the bobbin 402 by covering the upper surface of the bobbin 402, and therefore can prevent the bobbin 402 from being deformed due to an external impact.

[0152] The bobbin protection member 407 may be configured in the form of an injection molded product or a metal molded product. For example, the bobbin protection member 407 may be configured of a fiber reinforced material, a composite resin containing a fiber reinforced material, or a metal. For example, the bobbin protection member 407 may also have a heat dissipation function for dissipating heat generated when the sound generating units 410 and 430 are driven. The fiber reinforced material may be any one of carbon fiber reinforced plastics (CFRP), glass fiber reinforced plastics (GFRP), and graphite fiber reinforced plastics (GFRP), or a combination thereof, but is not limited thereto.

[0153] The bobbin protection member 407 can be bonded or connected to the bobbin 402 via a double-sided tape or an adhesive resin. For example, the adhesive resin can be, but is not limited to, an epoxy resin or an acrylic resin.

[0154] The bobbin protection member 407 can be attached or connected to the rear cover portion 310 of the rear cover 300 via a double-sided tape or an adhesive resin.

[0155] Fig. 7 is a graph showing the frequency-sound pressure characteristics of the first vibration generating module and the second vibration generating module according to an embodiment of the present application. In Fig. 7, the solid line shows the frequency-sound pressure characteristics of the first vibration generating module 400 using a voice coil method, and the dotted line shows the frequency-sound pressure characteristics of the second vibration generating module 500 using a piezoelectric method. In Fig. 7, the horizontal axis shows frequency (Hz) and the vertical axis shows sound pressure (Sound Pressure Level, dB).

[0156] 7, the frequency-sound pressure characteristic (solid line) of the first vibration generating module 400 is relatively superior in sound pressure characteristics at frequencies below 3 kHz or in the low frequency band compared to the frequency-sound pressure characteristic (dotted line) of the second vibration generating module 500, and the frequency-sound pressure characteristic (dotted line) of the second vibration generating module 500 is relatively superior in sound pressure characteristics at frequencies above 3 kHz or in the mid-high frequency band compared to the frequency-sound pressure characteristic (solid line) of the first vibration generating module 400. Therefore, the display device according to the embodiment of the present application may include a first vibration generating module 400 having relatively superior bass output characteristics to improve the bass band sound generated by the vibration of the display module, and may include a second vibration generating module 500 having relatively superior treble output characteristics to improve the mid-high frequency band sound generated based on the vibration of the display module.

[0157] Fig. 8 is a graph showing the acoustic output characteristics of a display device according to an embodiment of the present application. In Fig. 8, the two-dot chain line is a graph showing the acoustic output characteristics of a display device according to a comparative example in which neither the system rear cover box nor the system rear cover duct shown in Fig. 5a is applied, the dotted line is a graph showing the acoustic output characteristics of a display device including a system rear cover to which only the system rear cover box shown in Fig. 5a is applied, and the solid line is a graph showing the acoustic output characteristics of a display device including a system rear cover to which both the system rear cover box and the system rear cover duct shown in Fig. 5a are applied. In Fig. 8, the horizontal axis shows frequency (Hz) and the vertical axis shows sound pressure (dB).

[0158] 8, the acoustic output characteristic (dotted line) of the display device including the system back cover box is about 10 dB higher in the frequency range of about 3 kHz or less than the acoustic output characteristic (two-dot chain line) of the display device of the comparative example. Also, the acoustic output characteristic (solid line) of the display device including both the system back cover box and the system back cover duct is about 5 dB higher in the frequency range of about 3 kHz or less than the acoustic output characteristic (dotted line) of the display device including only the system back cover box 611, and the sound pressure characteristic is also high at frequencies above 3 kHz or in the mid-to-high frequency range.

[0159] Fig. 9 is a graph showing the acoustic output characteristics of a display device according to an embodiment of the present application. In Fig. 9, the dotted line is a graph showing the acoustic output characteristics of a display device including a rear cover to which the first rear cover hole shown in Figs. 2 to 4 is not applied, and the solid line is a graph showing the acoustic output characteristics of a display device including a rear cover to which the first rear cover hole shown in Figs. 2 to 4 is applied. In Fig. 9, the horizontal axis represents frequency (Hz) and the vertical axis represents sound pressure level (dB).

[0160] A certain low-frequency range including a frequency of about 170Hz is classified as so-called noise or abnormal sound (BSR (buzz, squeak, rattle) noise), so there is a demand for improvement and quality assurance in this area. Buzz noise is a sound that the diaphragm of a vibration generating module makes by itself like a drum, and can be a noise that occurs when the natural vibration frequency of the vibrating vibrator is the same as the vibration frequency that enters from the outside. Squeak noise is a sound that occurs due to friction in the shear direction between vibration generating module parts, and can be a noise that occurs when two vibrators come into contact and then horizontal displacement occurs on the surface, causing repeated fastening and separation of the two vibrators. Rattle noise is a sound that occurs due to vertical collision between vibration generating module parts, and can be a noise that occurs when impact energy is released into the air due to the collision phenomenon between vibrators that vibrate due to external vibration or force.

[0161] 2 to 4, a display device including the vibration generating module 400, 500 may generate acoustic vibration noise such as noise or abnormal sound due to structural features of the display device, and such acoustic vibration noise can be reduced in a specific resonance frequency band by using a Helmholtz resonator that can be formed by the rear cover hole 311, the rear cover part 310, and the first vibration generating module 400, thereby reducing noise or abnormal sound (BSR noise) including a frequency of about 170 Hz. The detailed structure of the Helmholtz resonator will be described later with reference to FIG. 10.

[0162] As shown in FIG. 9, the acoustic output characteristic (solid line) of a display device including a rear cover 300 to which a rear cover hole 311 is applied is reduced by about d1 in sound pressure characteristics at a frequency corresponding to about 170 Hz compared to the acoustic output characteristic (dotted line) of a display device including a rear cover 300 to which a rear cover hole 311 is not applied. This is because, by setting the resonant frequency of the Helmholtz resonator described above to about 170 Hz, the sound pressure of a frequency corresponding to noise or abnormal sound (BSR noise) can be reduced by the resonance of the Helmholtz resonator.

[0163] 9, the sound output characteristic (solid line) of the display device including the rear cover 300 with the rear cover hole 311 is higher by about d2 in sound pressure characteristic at a frequency corresponding to about 2.5 kHz than the sound output characteristic (dotted line) of the display device including the rear cover 300 without the rear cover hole 311. This is due to the air duct resistance generated by the rear cover hole 311 and the improved efficiency of the first vibration generating module 400 due to the characteristics of the Helmholtz resonator.

[0164] The Helmholtz resonator formed by the rear cover hole 311, the rear cover unit 310, and the first vibration generating module 400 can amplify or attenuate a specific frequency. In addition, the application of the rear cover hole 311 to the rear cover unit 310 causes a change in the flow of the air layer excited by the first vibration generating module 400, so that a change in the frictional force of the air flow can occur, which can be linked to the efficiency of the first vibration generating module 400. The frictional force of the air flow that can be generated by the introduction of the rear cover hole 311 can be an air duct resistance, and the air duct can be an opening that exists on the air flow path, such as the rear cover hole 311. The resistance of the air duct will be described later with reference to FIG. 10.

[0165] Therefore, the Helmholtz resonator formed by the rear cover hole 311, the rear cover part 310, and the first vibration generating module 400 can have the effect of attenuating noise or abnormal sound (BSR noise) at a set frequency. The Helmholtz resonator can prevent a decrease in efficiency of the first vibration generating module 400 by optimizing the frictional force of the flow generated by the first vibration generating module 400. Therefore, the present application can improve sound pressure over a predetermined frequency or the entire low, mid, and high frequency bands by optimizing the position of the rear cover hole 311.

[0166] FIG. 10 is a diagram showing a Helmholtz resonator formed in a display device according to an embodiment of the present application.

[0167] The resonant frequency of the Helmholtz resonator can be expressed as the following equation (1).

[0168] [Formula 1] TIFF0007625661000001.tif21170

[0169] In equation (1), "f" (or f) is the resonant frequency, "A" is the cross-sectional area of ​​the opening or hole of the Helmholtz resonator, "ι" (or l) is the length of the opening or hole of the Helmholtz resonator, "V" is the volume of the Helmholtz resonator, and "c" is the sound wave speed (at 15 degrees Celsius (℃), "c" is 340 m / sec, and for every 1 degree Celsius increase, "c" increases by 0.6 m).

[0170] 10, the volume (V) of the Helmholtz resonator may be calculated by setting the dimensions of the rear cover part 310 corresponding to the first vibration generating module 400 or the dimensions of the effective area of ​​the rear cover part 310 vibrated by the first vibration generating module 400, and multiplying this by a predetermined height. For example, if the area corresponding to the first vibration generating module 400 and the rear cover part 310 vibrated by the first vibration generating module 400 is set to 64 mm×47 mm, the maximum displacement due to the vibration of the first vibration generating module 400 is 1.2 mm, the thickness of the rear cover part 310 is 0.8 mm, and the effective air gap between the rear cover part 310 and a structure (backlight unit) disposed on the upper part of the rear cover part 310 is 0.5 mm, the height of the Helmholtz resonator may be set to 2.5 mm (1.2 mm+0.8 mm+0.5 mm) by adding these together.

[0171] Therefore, the volume (V) of the Helmholtz resonator can be calculated by multiplying the area of ​​the first vibration generating module 400 where the first vibration generating module 400 is excited by the height of the Helmholtz resonator. In addition, when a rear cover hole 311 having a predetermined size is formed in the rear cover part 310, the rear cover hole 311 communicates with an effective air gap and is separated from the first vibration generating module 400, the distance between the first vibration generating module 400 and the rear cover hole 311 can be the length (l) of the opening or hole part of the Helmholtz resonator, and the cross-sectional area of ​​the rear cover hole 311 can be the area (A) of the opening or hole part of the Helmholtz resonator.

[0172] As shown in equation (1), the resonant frequency (f) of the Helmholtz resonator is proportional to the cross-sectional area (A) of the opening or hole portion of the back cover hole 311. For example, the narrower the cross-sectional area of ​​the opening of the back cover hole 311, the lower the sound, and the larger the volume (V) of the Helmholtz resonator and the longer the length (l) of the opening or hole portion of the back cover hole 311, the lower the frequency.

[0173] Referring to equation (1) and FIG. 9, when the display device according to the embodiment of the present application has a Helmholtz resonator formed by the rear cover hole 311, the rear cover part 310, and the first vibration generating module 400, by adjusting the distance between the rear cover hole 311 and the first vibration generating module 400, or the distance (l) and cross-sectional area (A) of the opening or hole part of the rear cover hole 311 corresponding to the Helmholtz resonator, and the volume (V) of the Helmholtz resonator, sound vibration noise of a selected bass range frequency can be reduced and minimized as much as possible.

[0174] In addition, the friction loss of flow due to the air duct resistance can be calculated as follows:

[0175] [Formula 2] TIFF0007625661000002.tif12170

[0176] In formula (2), "Δp" is the friction force of the air duct (opening), "d" is the diameter of the air duct (opening), and "q" is the air flow. As shown in formula (2), by introducing an air duct (opening) of a certain size, the higher the air flow, the higher the friction force, and the larger the diameter of the air duct (opening), the lower the friction force.

[0177] Combining Equation 1 and Equation 2, the common factors of the two equations may be the area (A) of the opening or hole of the Helmholtz resonator corresponding to the rear cover hole 311 and the diameter (d) of the opening or hole of the air duct. In addition, Equation (1) may include the distance (ι) of the rear cover hole 311 from the first vibration generating module 400, which is an independent adjustment factor for Equation (2). Therefore, the present application has an effect of amplifying or attenuating the sound pressure of a set or adjusted frequency using the Helmholtz resonator while reducing or minimizing as much as possible the loss of frictional force caused by the air duct, for example, the opening or hole.

[0178] Therefore, the display device according to an embodiment of the present application can output a first sound (S1) in a first range band generated by vibration of a central portion (CP) of the display module 100 (or a display panel) due to vibration of the first vibration generating module 400 and a second sound (S2) in a second range band generated by vibration of an end portion (EP) of the display module 100 (or a display panel) due to vibration of the second vibration generating module 500 to the front (FD) of the display panel 110. Therefore, the display device can provide a more accurate sound to a listener, and can improve the listener's (or viewer's) immersive feeling due to the harmony (or agreement) between the image and the sound.

[0179] In addition, the display device according to one embodiment of the present application can output sounds having a wide range of sounds by outputting a first sound (S1) in a first frequency band using a voice coil type first vibration generating module 400 having relatively excellent low frequency output characteristics, and outputting a second sound (S2) in a second frequency band using a second vibration generating module 500 including a piezoelectric element having relatively excellent high frequency output characteristics.

[0180] In addition, the display device according to one embodiment of the present application can realize stereo sound by providing left sound through the first sound generating unit 410 and first piezoelectric vibration unit 510 arranged in the first middle portion (C1) and first end portion (EP1) of the display module 100, and right sound through the second sound generating unit 430 and second piezoelectric vibration unit 530 arranged in the second middle portion (C2) and second end portion (EP2) of the display module 100.

[0181] In addition, in the display device according to the embodiment of the present application, sound waves are directly transmitted (or propagated) to the display module 100 by vibrations of the first vibration generating module 400 and the second vibration generating module 500 through the first and second holes 313 and 315 provided in the rear cover part 310 of the rear cover 300 so as to overlap the first vibration generating module 400 and the second vibration generating module 500, respectively, so that the sound pressure characteristics and sound quality of the sounds (S1, S3) can be further improved. In addition, in the display device according to the embodiment of the present application, the Helmholtz resonator formed along the rear cover hole 311 formed in the rear cover 300 reduces low-frequency noise characteristics, so that the acoustic performance and acoustic efficiency can be improved.

[0182] Fig. 11 is another cross-sectional view taken along line II' in Fig. 1. Fig. 12 is an enlarged view of part B in Fig. 11. Fig. 13 is an enlarged view of part "C" in Fig. 11.

[0183] Figures 11 to 13 show a display device in which the structures of the first and second vibration generating modules are modified from those shown in Figure 3. Therefore, in the following description, only the first and second vibration generating modules will be described in detail, and the remaining components will be given the same reference numerals as in Figure 3, and duplicate descriptions will be omitted or will be described briefly.

[0184] 1, 11 and 12, a first vibration generating module 400 according to another embodiment of the present application may include first and second sound generating units 410 and 430.

[0185] Each of the first and second sound generating units 410, 430 may be supported by the rear cover part 310 so as to cover a first hole 313 formed in the rear cover part 310 of the rear cover 300. Each of the first and second sound generating units 410, 430 may vibrate based on an acoustic signal to vibrate the central portion (CP) of the display module 100, thereby generating a first sound (S1) at the central portion (CP) of the display module 100. For example, each of the first and second sound generating units 410, 430 may vibrate based on an acoustic signal to generate a sound wave, which may pass through the first hole 313 and be propagated (or transmitted) to the display module 100, and the central portion (CP) of the display module 100 may vibrate due to the sound wave transmitted through the first hole 313, thereby outputting the first sound (S1) at the central portion (CP) of the display module 100 to the front (FD) of the display module 100.

[0186] According to an embodiment, the first hole 313 can serve as an acoustic wave propagation path (or acoustic energy incidence portion) through which sound waves (or sounds) or acoustic energy generated by vibration of the first and second sound generating units 410, 430 propagate (or are incident) directly to the rear surface of the display module 100.

[0187] According to this embodiment, each of the first and second sound generating units 410, 430 vibrates independently without vibrating the rear cover part 310, and therefore can directly vibrate the central portion (CP) of the display module 100 without using the rear cover part 310 as a diaphragm. This reduces or minimizes the vibration of the rear cover part 310, generates stable sound pressure, and reduces or minimizes the generation of noise associated with the vibration of the rear cover part 310.

[0188] Each of the first and second sound generating units 410, 430 according to the embodiment of the present application may include a module frame 401, a bobbin 402, a magnet member 403, a coil 404, a center pole 405, and a damper 406. For example, in each of the first and second sound generating units 410, 430, the module frame 401 may be expressed as a fixed part fixed to the rear cover 300, and the bobbin 402, the magnet member 403, the coil 404, the center pole 405, and the damper 406 may be expressed as a vibration part for vibrating the display module 100, but is not necessarily limited thereto.

[0189] The module frame 401 may be supported by the rear cover portion 310. The module frame 401 according to one embodiment may include a frame body 401a, an upper plate 401b, and a fixing bracket 401c.

[0190] The frame body 401a may be fixed to the rear cover portion 310. The frame body 401a may serve as a lower plate that supports the magnet member 403.

[0191] The upper plate 401b may be disposed at a front end of the frame body 401a to have a cylindrical shape with a hollow portion. The frame body 401a and the upper plate 401b may be formed as one body having a "U" shape. The frame body 401a and the upper plate 401b are not limited to the term and may be expressed by other terms such as a yoke. The frame body 401a and the upper plate 401b may have a size corresponding to the first hole 313 in the rear cover part 310 of the rear cover 300.

[0192] The fixing bracket 401c may protrude from a side surface of the upper plate 401b. The fixing bracket 401c may be fixed to the rear cover portion 310 by the second connecting member 800. In this way, the module frame 401 may be fixed to the rear cover portion 310.

[0193] The bobbin 402 may be disposed on the module frame 401 such that a portion of the uppermost side can be inserted or accommodated in the first hole 313 of the rear cover part 310. The bobbin 402 is substantially the same as the bobbin shown in FIG. 6 except that the bobbin 402 vibrates, for example, moves up and down, due to a magnetic force in the area 313a overlapping with the first hole 313 of the rear cover part 310 to generate sound waves in the area 313a overlapping with the first hole 313 of the rear cover part 310, and therefore a duplicated description will be omitted.

[0194] The magnet member 403 may be disposed on the module frame 401 so as to be housed in the hollow portion 402a of the bobbin 402. The coil 404 is wound so as to surround the lower outer peripheral surface of the bobbin 402, and receives an acoustic signal (or a voice signal) from the outside. The center pole 405 may be disposed on the magnet member 403 to guide the vibration of the bobbin 402. The damper 406 may be disposed between the module frame 401 and the bobbin 402. The magnet member 403, the coil 404, the center pole 405, and the damper 406 are substantially the same as the magnet member, the coil, the center pole, and the damper shown in FIG. 6, except that they are disposed so as not to overlap with the rear cover portion 310, and only overlap with the first hole 313, and therefore, repeated description will be omitted.

[0195] The second connecting member 800 may be interposed between the rear cover part 310 around the first hole 313 and the fixing bracket 401c of the module frame 401 to connect (or connect) or fix the sound generating units 410, 430 to the rear cover 300. The second connecting member 800 may include a double-sided tape or a double-sided foam tape having an adhesive layer. The adhesive layer of the second connecting member 800 according to an example may include an acrylic-based or urethane-based adhesive material. For example, the adhesive layer of the second connecting member 800 may include a urethane-based adhesive material having a relatively soft property, rather than an acrylic-based adhesive material having a relatively high hardness, in order to reduce or minimize as much as possible the transmission of vibrations of the sound generating units 410, 430 to the rear cover part 310, but is not necessarily limited thereto.

[0196] In the second connecting member 800 according to an embodiment, the first thickness (T1) of the rear cover 300 may have a second thickness (T2) that is thicker than the first thickness (T1) of the rear cover unit 310. The second thickness (T2) of the second connecting member 800 according to an embodiment may be 1 to 4 times the first thickness (T1) of the rear cover unit 310. For example, when the second thickness (T2) of the second connecting member 800 is less than 1 time the first thickness (T1) of the rear cover unit 310 (for example, the same thickness), the distance (or gap or interval) between the rearmost surface of the display module 100 and the bobbin 402 is relatively short, and therefore the bobbin 402 vibrating along the thickness direction (Z) of the display module 100 may pass (or penetrate) the first hole 313 and come into physical contact with the rearmost surface of the display module 100, resulting in damage. On the other hand, if the second thickness (T2) of the second connecting member 800 is more than four times the first thickness (T1) of the rear cover unit 310, the distance (or gap or interval) between the rearmost part of the display module 100 and the bobbin 402 is relatively long, and therefore the transmission loss of the high-frequency sound waves increases in proportion to the distance, so that the sound of the mid-high frequency range may not be realized or the sound pressure of the mid-high frequency range may decrease, and an acoustic separation phenomenon may occur between the sound of the mid-high frequency range generated by the first vibration generating module 400 and the sound of the deep bass range generated by the second vibration generating module 500. Therefore, the bobbin 402 stably vibrates within the first hole 313 without physical contact with the rearmost part of the display module 100, and in order to realize the sound of the mid-high frequency range and generate the sound pressure of the mid-high frequency range, the second thickness (T2) of the second connecting member 800 may be set or adjusted to be one to four times the first thickness (T1) of the rear cover unit 310.

[0197] Each of the first and second sound generating units 410 and 430 according to the embodiment of the present application may further include a bobbin protection member 408 disposed on the upper portion of the bobbin 402 .

[0198] The bobbin protection member 408 may be formed in a cylindrical structure having an opening overlapping the hollow portion 402a of the bobbin 402, and may be coupled or connected to the upper surface of the bobbin 402. The bobbin protection member 408 according to an example may cover the upper surface of the bobbin 402 to protect the bobbin 402, thereby preventing deformation of the bobbin 402 due to an external impact.

[0199] The bobbin protection member 408 according to another embodiment is formed in a plate-like structure covering the hollow portion 402a and the entire upper surface of the bobbin 402, and can be coupled or connected to the upper surface of the bobbin 402. The bobbin protection member 408 according to another embodiment can protect the bobbin 402 by covering the entire upper surface of the bobbin 402, thereby preventing deformation of the bobbin 402 due to external impact, and can be arranged on the bobbin 402 in a plate-like structure to increase sound pressure generated by vibration of the bobbin 402.

[0200] Each of the first and second sound generating units 410, 430 according to the embodiments of the present application can vibrate independently without using the rear cover part 310 as a diaphragm, and pass (or penetrate) through the first hole 313 to generate sound waves (or sounds) that directly vibrate the display module 100. This can reduce or minimize as much as possible the vibration of the rear cover part 310, generate stable sound pressure, and reduce or minimize as much as possible the generation of noise associated with the vibration of the rear cover part 310.

[0201] 1, 11 and 13, a second vibration generating module 500 according to another embodiment of the present application may include first and second piezoelectric vibration units 510 and 530.

[0202] Each of the first and second piezoelectric vibration units 510, 530 may be supported by the rear cover part 310 so as to cover the second hole 315 formed in the rear cover part 310 of the rear cover 300. Each of the first and second piezoelectric vibration units 510, 530 may vibrate based on an acoustic signal to vibrate the end part (EP) of the display module 100, thereby generating a second sound (S2) from the end part (EP) of the display module 100. For example, each of the first and second piezoelectric vibration units 510, 530 may vibrate based on an acoustic signal to generate a sound wave, which may pass through the second hole 315 and be propagated (or transmitted) to the display module 100, and the end part (EP) of the display module 100 may vibrate based on the sound wave transmitted through the second hole 315, so that the second sound (S2) may be output to the front (FD) of the display module 100 at the end part (EP) of the display module 100.

[0203] According to an embodiment of the present application, the second hole 315 can act as an acoustic wave propagation path (or acoustic energy incidence part) through which sound waves (or sounds) or acoustic energy generated by the vibration of the first and second piezoelectric vibration units 510, 530 propagate (or are incident) directly to the rear surface of the display module 100.

[0204] According to an embodiment of the present application, each of the first and second piezoelectric vibration units 510, 530 vibrates independently (or independently) without vibrating the rear cover part 310, thereby directly vibrating the end portion (EP) of the display module 100 without using the rear cover part 310 as a diaphragm, thereby reducing or minimizing as much as possible the vibration of the rear cover part 310, generating stable sound pressure, and reducing or minimizing as much as possible the generation of noise associated with the vibration of the rear cover part 310.

[0205] Each of the first and second piezoelectric vibration units 510 , 530 according to an embodiment of the present application may include a base plate 501 and a piezoelectric element 503 .

[0206] The base plate 501 may be coupled or connected to the rear cover portion 310 of the rear cover 300 via a third adhesive member 805 to cover the second hole 315 in the rear cover portion 310. For example, the base plate 501 may have a size larger than the second hole 315.

[0207] The base plate 501 can be used as a diaphragm that generates sound pressure inside the second hole 315. The base plate 501 according to an example may be made of any one of metal materials such as stainless steel, aluminum (Al), magnesium (Mg) alloy, magnesium, lithium (Li) alloy, and aluminum (Al) alloy, but is not necessarily limited thereto. For example, the base plate 501 may have a third thickness (T3) that is thinner than the first thickness (T1) of the rear cover part 310 in order to generate a sound in the mid-high frequency range. If the third thickness (T3) of the base plate is thicker than the first thickness (T1) of the rear cover part 310, it may be difficult for the vibration of the piezoelectric element 503 to propagate inside the second hole 315. The base plate 501 vibrates due to the vibration of the piezoelectric element 503 to generate a sound (or sound pressure) in the mid-high frequency range of 3 kHz or more, and propagate it inside the second hole 315.

[0208] The third adhesive member 805 is interposed between the rear cover part 310 and the base plate 501 around the second hole 315 to combine (or connect) or fix the piezoelectric vibration units 510, 530 to the rear cover 300. The third adhesive member 805 may include a double-sided tape or a double-sided foam tape having an adhesive layer. The adhesive layer of the third adhesive member 805 according to an example may include an acrylic-based or urethane-based adhesive material. For example, the adhesive layer of the third adhesive member 805 may include a urethane-based adhesive material having a relatively soft property, rather than an acrylic-based adhesive material having a relatively high hardness, in order to reduce or minimize as much as possible the transmission of vibration of the piezoelectric vibration units 510, 530 to the rear cover part 310, but is not necessarily limited thereto.

[0209] The piezoelectric element 503 can be disposed on the base plate 501 to vibrate the base plate 501. The piezoelectric element 503 can be disposed on the rear surface of the base plate 501 so as to overlap with the second hole 315 of the rear cover part 310. For example, the piezoelectric element 503 can be coupled to the base plate 501 via a third connecting member 502.

[0210] The piezoelectric element 503 may include a piezoelectric material layer having a piezoelectric effect. These piezoelectric elements 503 have substantially the same configuration (or structure) as the first piezoelectric element 511 or the second piezoelectric element 531 shown in FIG. 4, so a duplicated description will be omitted.

[0211] The piezoelectric element 503 may have a size smaller than the second hole 315 so as to be disposed within an area 315a overlapping with the second hole 315 of the rear cover part 310. For example, the exact center of the piezoelectric element 503 may be located at the exact center of the second hole 315. The exact center of the piezoelectric element 503 may be located at the exact center of the second hole 315.

[0212] The third connecting member 502 may be, but is not limited to, a double-sided tape or a natural curing adhesive. For example, the third connecting member 502 may be a thermosetting adhesive or a photocuring adhesive. In this case, the characteristics of the piezoelectric element 503 may be deteriorated due to heat generated during the curing process of the third connecting member 502.

[0213] Each of the first and second piezoelectric vibration units 510 and 530 according to the embodiment of the present application may further include a cover plate 505 .

[0214] The cover plate 505 may be coupled to the rear surface of the piezoelectric element 503 via the fourth connecting member 504. The cover plate 505 may play a role in protecting the piezoelectric element 503 by covering the rear surface of the piezoelectric element 503. In addition, the cover plate 505 may reinforce the mass of the piezoelectric vibration units 510 and 530 and reduce the resonance frequency of the piezoelectric vibration units 510 and 530 due to the increase in mass, thereby increasing the low-frequency sound pressure characteristics of the piezoelectric vibration units 510 and 530. The cover plate 505 according to an example may have the same material and thickness as the base plate 501. However, the cover plate 505 may have a different material or thickness from the base plate 501 depending on the acoustic characteristics required for the piezoelectric vibration units 510 and 530.

[0215] The fourth connecting member 504 may be, but is not limited to, a double-sided tape or a natural curing adhesive. For example, the fourth connecting member 504 may be a thermosetting adhesive or a photocuring adhesive, and the characteristics of the piezoelectric element 503 may be deteriorated due to heat generated during the curing process of the fourth connecting member 504.

[0216] Therefore, the display device according to the embodiment of the present application can have the same effect as the display device shown in Figures 2 to 4. In addition, the display device according to the embodiment vibrates the display module 100 by sound waves generated by the vibration of each of the first vibration generating module 400 and the second vibration generating module 500 and passing through each of the second and third rear cover holes 313 and 315 to output sounds (S1, S2), so that sounds (S1, S2) can be output by the vibration of the display module 100 without using the rear cover 300 as a diaphragm. As a result, the vibration of the rear cover part 310 is reduced or minimized as much as possible, so that the generation of noise caused by the vibration of the rear cover part 310 can be prevented, reduced or minimized as much as possible.

[0217] Fig. 14 is a diagram showing the rear of a display device according to another embodiment of the present application, Fig. 15 is a cross-sectional view taken along line II-II' in Fig. 14, and Fig. 16 is a cross-sectional view of the rear cover shown in Fig. 15, which is a modified structure of the rear cover in the display device shown in Figs. 1 to 13. Therefore, in the following description, only the rear cover and backlight unit and related configurations will be described in detail, and the remaining configurations will be given the same reference numerals as in Figs. 1 to 13, and duplicated descriptions will be omitted or will be described briefly.

[0218] 14 to 16, in a display device according to another embodiment of the present application, a rear cover 300 can support the backlight unit 130 of the display module 100 such that an air gap 132 is provided inside the backlight unit 130.

[0219] The rear cover 300 according to an embodiment may include a rear cover portion 310 that supports the rear surface of the display module 100 and a side cover portion 330 that is connected to and / or integrated with an edge of the rear cover portion 310 and supports the panel guide 200 .

[0220] The rear cover part 310 is disposed to cover the rear surface of the display module 100 and can support the display module 100. The rear cover part 310 can support the backlight unit 130 of the display module 100 and can support each of the first vibration generating module 400 and the second vibration generating module 500.

[0221] The rear cover part 310 may include a cross-sectional structure having a concave curved shape so that an internal air gap 132 may be provided inside the backlight unit 130. The internal air gap 132 (or air gap) of the backlight unit 130 may improve acoustic characteristics in the low frequency range by acting as a sound body for sound generated and propagated by vibration of the first vibration generating module 400. The rear cover part 310 is substantially the same as the above-described rear cover part except for including the cross-sectional structure having a concave curved shape, and therefore, a duplicated description of the remaining structure except for the cross-sectional structure having a concave curved shape will be omitted.

[0222] The rear cover part 310 according to an embodiment may have a cup structure in which a central portion (MP) overlapping with a middle line (CL) of the display module 100 protrudes toward a rear surface of the display device when viewed in the first direction (X) (or horizontal direction) of the display module 100. For example, the distance (or gap) between an upper surface of the rear cover part 310 and a rear surface of the display panel 110 may increase from the ends (EP1, EP2) to the middle line (CL) when viewed in the first direction (X) (or horizontal direction) of the display module 100.

[0223] In the rear cover part 310 according to an embodiment, based on the first direction (X) (or horizontal direction) of the display module 100, a distance (L2) (or depth) between a virtual plane (VPS) (or horizontal line) connecting one end and the other end of the rear cover part 310 and a central part (MP) of the rear cover part 310 may be 0.01% to 0.5% of an entire length (L1) of the rear cover part 310. For example, when the depth (L2) of the central part (MP) of the rear cover part 310 is 0% of the entire length (L1) of the rear cover part 310, the rear cover part 310 may have a substantially planar structure, in which case, an air gap 132 cannot be provided inside the backlight unit 130. In addition, if the depth (L2) of the central portion (MP) of the rear cover part 310 exceeds 0.5% of the entire length (L1) of the rear cover part 310, the distance (or size) of the air gap 132 inside the backlight unit 130 increases, and therefore, due to an increase in the transmission loss of the high-frequency sound wave proportional to the distance, the sound of the mid-high frequency band may not be realized or the sound pressure of the mid-high frequency band may decrease, and an acoustic separation phenomenon may occur between the sound of the mid-high frequency band generated by the first vibration generating module 400 and the sound of the deep low frequency band generated by the second vibration generating module 500, and the thickness of the display device may increase. Therefore, the depth (L2) of the central portion (MP) of the rear cover part 310 may be set to 0.01% to 0.5% of the entire length (L1) of the rear cover part 310 so that the air gap 132 of the backlight unit 130 can act as a sound box for improving the acoustic characteristics of the low frequency band.

[0224] The side cover part 330 may be bent from an edge of the rear cover part 310 to support the panel guide 200. The side cover part 330 may provide a backlight storage space on the rear cover part 310 and surround the side of the backlight unit 130 stored (or supported) in the backlight storage space (or space).

[0225] The rear cover 300 according to an embodiment may further include a reinforcing part 350. The reinforcing part 350 may be a rigidity reinforcing part since it can reinforce the rigidity of the rear cover 300, but is not limited thereto.

[0226] The reinforcing portion 350 protrudes from the rear cover portion 310 at a certain height, thereby enabling the rigidity of the rear cover 300 to be reinforced.

[0227] The reinforcing part 350 according to an embodiment may include an edge reinforcing part formed along an edge of the rear cover part 310, and a plurality of intermediate reinforcing parts in a middle cover region of the rear cover part 310 aligned with the first direction (X). The intermediate reinforcing parts may be arranged side by side with the first and second vibration generating modules 400, 500 therebetween.

[0228] The backlight unit 130 may include a reflective sheet 133 , a light guide plate 131 , a light source unit, and an optical sheet unit 135 .

[0229] The reflective sheet 133 may be disposed on the rear cover part 310 of the rear cover 300. The reflective sheet 133 may be disposed on the rear cover part 310 to have a concave shape along the concave shape of the rear cover part 310. For example, the reflective sheet 133 may be disposed on the rear cover part 310 to have a conformal shape that follows the shape of the rear cover part 310 as it is warped into a concave shape due to its own weight. The reflective sheet 133 may reduce or minimize light loss as much as possible by reflecting light incident from the light guide plate 131 toward the light guide plate 131.

[0230] The light guide plate 131 is disposed on the reflective sheet 133 so as to overlap the display panel 110, and may include a light incident surface provided on at least one side wall. The light guide plate 131 may include a light-transmitting plastic or glass material. The light guide plate 131 guides light incident from the light source through the light incident surface toward (or out of) the display panel 110.

[0231] The light guide plate 131 may be disposed on the reflective sheet 133 to have a concave shape that does not exactly match the concave shape of the rear cover part 310. For example, the light guide plate 131 may be disposed on the reflective sheet 133 to have a non-conformal shape that does not exactly match the shape of the reflective sheet 133 (or the rear cover part 310). As a result, the backlight unit 130 may include an air gap 132 between the reflective sheet 133 and the light guide plate 131. The air gap 132 may be provided between the reflective sheet 133 and the light guide plate 131 overlapping the central portion (CP) of the display module 100. The ends of the reflective sheet 133 and the light guide plate 131 overlapping the end portion (EP) of the display module 100 contact each other, and thus the air gap 132 is not provided between the reflective sheet 133 and the end of the light guide plate 131. The internal air gap 132 is provided between the reflective sheet 133 overlapping the central portion (CP) of the display module 100 and the light guide plate 131, and acts as a sound body for the sound generated and propagated by the vibration of the first vibration generating module 400, thereby improving the acoustic characteristics in the low-frequency range.

[0232] The light guide plate 131 may be curved into a concave shape due to its own weight and disposed on the reflective sheet 133. For example, when the rigidity of the light guide plate 131 is relatively low, the light guide plate 131 may be curved to follow the concave shape of the reflective sheet 133 (or the rear cover part 310) and disposed on the reflective sheet 133. Therefore, the air gap 132 is not provided between the reflective sheet 133 and the light guide plate 131. On the other hand, when the rigidity of the light guide plate 131 is relatively high, the light guide plate 131 is disposed on the reflective sheet 133 in a flat state without being curved due to its own weight, so that the internal air gap 132 may be formed between the light guide plate 131 and the remaining part of the reflective sheet 133 excluding both ends. For example, as the distance (or size) of the air gap 132 increases, the transmission loss of high-frequency sound waves increases in proportion to the distance, so that sound in the mid-high frequency range may not be realized or the sound pressure in the mid-high frequency range may decrease, and an acoustic separation phenomenon may occur between the sound in the mid-high frequency range generated by the first vibration generating module 400 and the sound in the mid-low frequency range generated by the second vibration generating module 500. Therefore, the light guide plate 131 may be made of a rigid material that can be curved concavely in a non-conformal shape that does not follow the concave shape of the reflective sheet 133 (or the rear cover part 310) and placed on the reflective sheet 133 in order to provide the air gap 132 between the reflective sheet 133 overlapping the central portion (CP) of the display module 100 and the light guide plate 131.

[0233] The light source unit irradiates light onto a light incident surface of the light guide plate 131. The light source unit may be disposed on the rear cover 300 so as to overlap with a first end of the display panel 110. The light source unit according to an example may include a plurality of light emitting diode elements mounted on a light source printed circuit board to irradiate light onto the light incident surface of the light guide plate 131.

[0234] The optical sheet unit 135 is disposed on the front surface of the light guide plate 131 to improve the brightness characteristics of the light emitted from the light guide plate 131. The optical sheet unit 135 may be disposed on the light guide plate 131 to have a conformal shape that directly follows the concave shape of the light guide plate 131.

[0235] Therefore, the display device according to the embodiment of the present application can have the same effects as the display device shown in Figures 11 to 13. In addition, the display device according to the embodiment of the present application can further improve the acoustic characteristics in the low frequency range due to the role of the air gap 132 provided between the light guide plate 131 and the reflective sheet 133 of the backlight unit 130 as a sound body due to the rear cover part 310 of the rear cover 300 having a cross-sectional structure with a concave curved shape.

[0236] 17a to 17g are diagrams showing various arrangements of the first and second vibration generating modules in a display device according to an embodiment of the present application, which are modifications of the arrangements of the first and second vibration generating modules in the display device shown in Figs. 1 to 16. Therefore, in the following description, the remaining configurations and structures, except for the arrangements of the first and second vibration generating modules, are substantially the same as those described above, and therefore repeated description will be omitted.

[0237] 17a to 17c, in a display device according to one embodiment of the present application, a first vibration generating module 400 includes first and second sound generating units 410, 430 respectively arranged in first and second end areas (EA1, EA2) of a rear cover part 310 based on a first direction (X), which is substantially the same as the first vibration generating module 400 of the display device shown in FIGS. 1 to 16, and therefore a duplicated description will be omitted.

[0238] In the display device according to the embodiment of the present application, the second vibration generating module 500 may include at least three piezoelectric vibration units 510, 530, 550, 570, 590 respectively disposed in at least three portions of the first to fourth end regions (EA1, EA2, EA3, EA4) and the central region (or central region) of the rear cover part 310. The first to fourth end regions (EA1, EA2, EA3, EA4) of the rear cover part 310 may correspond to or overlap with the first to fourth end portions of the display module, respectively.

[0239] As an example, as shown in FIG. 17a, the second vibration generating module 500 may include first to third piezoelectric vibration units 510, 530, and 550 disposed in the middle of the first to third end regions (EA1, EA2, and EA3) of the rear cover part 310. The first to third piezoelectric vibration units 510, 530, and 550 may correspond to or overlap the first to third end portions of the display module, respectively. As an example, the rear cover part 310 may include three second holes 315 in the first to third end regions (EA1, EA2, and EA3) so as to overlap the first to third piezoelectric vibration units 510, 530, and 550, respectively. Thus, the display device shown in FIG. 17a has the same effect as the display device shown in FIGS. 1 to 16, and the addition of the third piezoelectric vibration unit 550 may increase the stereoscopic effect of sound by the sound output to the left, right, and upper sides of the display module, and may have a five-channel sound output characteristic. These display devices may be suitable for use as monitors for gaming PCs, but are not limited to such.

[0240] 17b, the second vibration generating module 500 may include first to fourth piezoelectric vibration units 510, 530, 550, 570 disposed in the middle of the first to fourth end regions (EA1, EA2, EA3, EA4) of the rear cover part 310. The first to fourth piezoelectric vibration units 510, 530, 550, 570 may correspond to or overlap the first to fourth end portions of the display module, respectively. As an example, the rear cover part 310 may include four second holes 315 formed in the first to fourth end regions (EA1, EA2, EA3, EA4) to overlap the first to fourth piezoelectric vibration units 510, 530, 550, 570, respectively. 1 to 16, the display device shown in Fig. 17b can further increase the stereoscopic effect of the sound by the sound output from the left, right, top, and bottom of the display module by adding the third and fourth piezoelectric vibration units 550 and 570, and can have a six-channel sound output characteristic. Such a display device is more suitable for use as a monitor for a gaming PC, but is not limited thereto.

[0241] 17c, second vibration generating module 500 may include first to fourth piezoelectric vibration units 510, 530, 550, 570 respectively disposed in the middle of first to fourth end regions (EA1, EA2, EA3, EA4) of rear cover part 310, and a fifth piezoelectric vibration unit 590 disposed in a center region (or central region) of rear cover part 310. First to fourth piezoelectric vibration units 510, 530, 550, 570 may correspond to or overlap with the first to fourth end portions of the display module, respectively, and fifth piezoelectric vibration unit 590 may correspond to or overlap with the center portion (or central portion) of the display module. As an example, the rear cover part 310 may include five second holes 315 formed in the first to fourth end regions (EA1, EA2, EA3, EA4) to overlap with the first to fifth piezoelectric vibration units 510, 530, 550, 570, 590, respectively. Therefore, the display device shown in FIG. 17c has the same effect as the display device shown in FIG. 1 to FIG. 16, but the addition of the third to fifth piezoelectric vibration units 550, 570, 590 may further increase the stereoscopic effect of the sound by the sound output from the left side, right side, upper side, lower side, and center side (or center side) of the display module, and may have a seven-channel sound output characteristic. Such a display device may be more suitable for use as a monitor for a gaming PC, but is not limited thereto.

[0242] As another embodiment, in the display device shown in FIG. 17c, the fifth piezoelectric vibration unit 590 arranged in the exact center region (or central region) of the rear cover part 310 can be changed to an acoustic generating device, and for example, the bass band acoustic characteristics can be improved due to the amplification effect of the bass band acoustic generated by the acoustic generating unit arranged in the exact center region (or central region) of the rear cover part 310.

[0243] 17d and 17e, in the display device according to the embodiment of the present application, the first vibration generating module 400 may include first and second sound generating units 410, 430 arranged in the first and second end regions (EA1, EA2) of the rear cover part 310, respectively, based on the first direction (X). The first and second sound generating units 410, 430 may correspond to or overlap the first and second end portions of the display module, respectively. As an example, the rear cover part 310 may include two first holes 313 formed in the first and second end regions (EA1, EA2), respectively, to overlap the first and second sound generating units 410, 430, respectively. The first vibration generating module 400 is substantially the same as the first vibration generating module 400 of the display device shown in FIGS. 1 to 16, and therefore a duplicated description will be omitted.

[0244] In a display device according to one embodiment of the present application, the second vibration generating module 500 may include at least one piezoelectric vibration unit 510, 530, 550 arranged in at least one of the central region (or central region) and the third and fourth end regions (EA3, EA4) of the rear cover part 310.

[0245] As an example, as shown in FIG. 17d, the second vibration generating module 500 may include one piezoelectric vibration unit 510 disposed in the exact center region (or central region) of the rear cover part 310. One piezoelectric vibration unit 510 may correspond to or overlap with the exact center part (or central part) of the display module. As an example, the rear cover part 310 may include one second hole 315 formed in the exact center region (or central region) to overlap with one piezoelectric vibration unit 510. Thus, the display device shown in FIG. 17d has the same effect as the display device shown in FIGS. 1 to 16, and can output stereophonic sound by sounds output from the left side, right side, and exact center side (or central side) of the display module by the first and second sound generating units 410, 430 and one piezoelectric vibration unit 510, and can have three-channel sound output characteristics. In addition, the production cost can be reduced by reducing the number of piezoelectric vibration units 510, which are relatively expensive compared to the sound generating units 410, 430.

[0246] As another embodiment, as shown in FIG. 17e, the second vibration generating module 500 may include first to third piezoelectric vibration units 510, 530, 550 disposed in the exact center region (or central region) and third and fourth end regions (EA3, EA4) of the rear cover part 310, respectively. The first to third piezoelectric vibration units 510, 530, 550 may correspond to or overlap the exact center portion (or central portion) and third and fourth end portions of the display module, respectively. As an embodiment, the rear cover part 310 may include three second holes 315 formed in the exact center region (or central region) and third and fourth end regions (EA3, EA4), respectively, to overlap the first to third piezoelectric vibration units 510, 530, 550. 1 to 16, the display device shown in Fig. 17e can further increase the stereoscopic effect of the sound by the sound output from the left side, right side, top side, bottom side, and center side (or center side) of the display module by the first and second sound generating units 410, 430 and the first to third piezoelectric vibration units 510, 530, 550, and can have a five-channel sound output characteristic. Such a display device can be suitable for use as a monitor for a gaming PC, but is not limited thereto.

[0247] As another embodiment, in the display device shown in Fig. 17e, the first piezoelectric vibration unit 510 arranged in the exact center region (or central region) of the rear cover part 310 may be changed to an acoustic generating device. The first piezoelectric vibration unit 510 may correspond to or overlap with the exact center part (or central portion) of the display module. As an example, the bass band acoustic characteristics may be improved due to the amplification effect of the bass band acoustic generated by the acoustic generating unit arranged in the exact center region (or central region) of the rear cover part 310.

[0248] 17f and 17g, in the display device according to an embodiment of the present application, the first vibration generating module 400 may include one sound generating unit 410 disposed in the exact center region (or central region) of the rear cover part 310. One sound generating unit 410 may correspond to or overlap with the exact center part (or central portion) of the display module. As an example, the rear cover part 310 may include one first hole 313 formed in the exact center region (or central region) to overlap with one sound generating unit 410. Such a first vibration generating module 400 is substantially the same as the first vibration generating module 400 of the display device shown in FIGS. 1 to 16, and therefore a repeated description will be omitted.

[0249] In a display device according to one embodiment of the present application, the second vibration generating module 500 may include at least two piezoelectric vibration units 510, 530, 550, 570 respectively arranged in at least two of the first to fourth end regions (EA1, EA2, EA3, EA4) of the rear cover part 310.

[0250] 17f, the second vibration generating module 500 may include first and second piezoelectric vibration units 510, 530 disposed in the middle of the first and second end regions (EA1, EA2) of the rear cover part 310. The first and second piezoelectric vibration units 510, 530 may correspond to or overlap the first and second end portions of the display module, respectively. As an example, the rear cover part 310 may include two second holes 315 formed in the first and second end regions (EA1, EA2) to overlap the first and second piezoelectric vibration units 510, 530, respectively. Therefore, the display device shown in Figure 17f has the same effects as the display devices shown in Figures 1 to 16, but can output stereophonic sound by outputting sound from the left side, right side, and exact center side (or central side) of the display module using one sound generating unit 410 and first and second piezoelectric vibration units 510, 530, and can have three-channel sound output characteristics.The low-frequency sound characteristics can be improved due to the amplification effect of the low-frequency sound generated by the sound generating unit 410 arranged in the exact center area (or central area) of the rear cover part 310.

[0251] As another embodiment, as shown in FIG. 17g, the second vibration generating module 500 may include first to fourth piezoelectric vibration units 510, 530, 550, 570 disposed in the middle of the first to fourth end regions (EA1, EA2, EA3, EA4) of the rear cover part 310. The first to fourth piezoelectric vibration units 510, 530, 550, 570 may correspond to or overlap the first to fourth end portions of the display module, respectively. As an example, the rear cover part 310 may include four second holes 315 in the first to fourth end regions (EA1, EA2, EA3, EA4) so ​​as to overlap the first to fourth piezoelectric vibration units 510, 530, 550, 570, respectively. 1 to 16, the display device shown in Fig. 17g can further increase the stereoscopic effect of the sound by outputting the sound from the left side, right side, top side, bottom side, and center side (or center side) of the display module by one sound generating unit 410 and first to fourth piezoelectric vibration units 510, 530, 550, 570, and can have a five-channel sound output characteristic. These display devices can be suitable for use as monitors for gaming PCs, but are not limited thereto.

[0252] Fig. 18 is a graph showing frequency-sound pressure characteristics according to the arrangement location of the second vibration generating module in the first direction in a display device according to an embodiment of the present application. In Fig. 18, the thick solid line shows the frequency-sound pressure characteristics of a display device of a first experimental example including a second vibration generating module arranged in the exact center region (or central region) of the rear cover part, the dotted line shows the frequency-sound pressure characteristics of a display device of a second experimental example including a second vibration generating module arranged in an edge region of the rear cover part, and the dashed and dotted line shows the frequency-sound pressure characteristics of a display device of a third experimental example including a second vibration generating module arranged in an intermediate region between the exact center region (or central region) and the edge region of the rear cover part. In Fig. 18, the horizontal axis shows frequency (Hz) and the vertical axis shows sound pressure (Sound Pressure Level, dB).

[0253] As can be seen from Fig. 18, the acoustic output characteristic of the display device of the first experimental example (dotted line) has relatively excellent sound pressure characteristics in the frequency range below 5 kHz and above 10 kHz. The acoustic output characteristic of the display device of the second experimental example (thick solid line) and the acoustic output characteristic of the display device of the third experimental example (dashed dotted line) have almost similar sound pressure characteristics. Also, each of the acoustic output characteristics of the display devices of the first to third experimental examples has a sound pressure characteristic of 50 dB or more in the frequency range above 500 Hz.

[0254] Therefore, taking into consideration the sound pressure characteristics in the frequency range below 5 kHz of the display device according to the present application, it may be preferable to place the second vibration generating module in the exact central region (or central region) or end region of the rear cover part, as shown in Figures 2, 14, and 17a to 17g.

[0255] Fig. 19 is a graph showing the frequency-sound pressure characteristics of the second vibration generating module according to the first and second embodiments in a display device according to an embodiment of the present application. In Fig. 19, the dotted line shows the frequency-sound pressure characteristics of a display device including the second vibration generating module according to the first embodiment shown in Fig. 4, and the thick solid line shows the frequency-sound pressure characteristics of a display device including the second vibration generating module according to the second embodiment having a base plate as shown in Fig. 13. In Fig. 19, the horizontal axis shows frequency (Hz) and the vertical axis shows sound pressure (Sound Pressure Level, dB).

[0256] 19, it can be seen that the acoustic output characteristics (dotted line) of the display device including the second vibration generating module according to the first embodiment have relatively high sound pressure characteristics in a frequency range of 500 Hz or less, compared with the acoustic output characteristics (thick solid line) of the display device including the second vibration generating module according to the second embodiment. Also, it can be seen that the acoustic output characteristics (dotted line) of the display device including the second vibration generating module according to the second embodiment have relatively high sound pressure characteristics in a frequency range of 500 Hz or more, compared with the acoustic output characteristics (dotted line) of the display device including the second vibration generating module according to the first embodiment.

[0257] Therefore, the second vibration generating module according to the first embodiment can be applied to a display device that requires a relatively high sound pressure characteristic in a frequency range of 500 Hz or less, and the second vibration generating module according to the second embodiment can be applied to a display device that requires a relatively high sound pressure characteristic in a frequency range of 500 Hz or more.

[0258] The display device according to the present application can be applied to various applications that output sound by vibration of a display module without a separate speaker. The display device according to the present application can be applied to mobile devices, video phones, smart watches, watch phones, wearable apparatuses, foldable apparatuses, rollable apparatuses, bendable apparatuses, flexible apparatuses, curved apparatuses, electronic organizers, electronic books, portable multimedia players (PMPs), personal digital assistants (PDAs), MP3 players, mobile phones, medical devices, desktop PCs, laptop PCs, netbook computers, workstations, navigation systems, car navigation systems, car display devices, televisions, wallpaper devices, signage devices, game devices, notebook computers, monitors, cameras, video cameras, and home appliances. When the display device of the present application is applied to a mobile device or the like, it may be, but is not limited to, a speaker or a receiver.

[0259] The display device according to the present application can be described as follows.

[0260] The display device according to the present application may include a display module including a display panel for displaying images, a panel guide supporting the rear end of the display panel, a rear (back) cover supporting the panel guide and covering the rear of the display module, a first vibration generating module disposed in a middle portion of the rear cover and vibrating the middle portion of the display panel, and a second vibration generating module disposed at an end of the rear cover and vibrating the end of the display panel.

[0261] According to some examples of the present application, the rear cover may further include a rear cover portion that supports the rear surface of the display panel, and side cover portions that are provided at ends of the rear cover portion and support the panel guides.

[0262] According to some examples of the present application, the rear cover part may further include a first hole provided in a middle part of the rear cover and spaced apart from one side of the first vibration generating module.

[0263] According to some examples of the present application, the device may further include a second hole in the rear cover portion formed in an area of ​​the rear cover portion corresponding to the first vibration generating module and the second vibration generating module.

[0264] According to some examples of the present application, the system may further include a system back cover that houses the display module, the panel guide, the rear cover, the first vibration generating module and the second vibration generating module, and the system back cover may include a rear structure that covers the rear of the display panel and the rear of the rear cover part, and a side structure provided at an edge of the rear structure and supporting a side of the display panel.

[0265] According to some examples of the present application, the rear structure of the system rear cover may further include a system rear cover box fastened to the rear cover part and sealing the first vibration generating module and the first hole of the rear cover part of the rear cover.

[0266] According to some examples of the present application, the system back cover box can improve the sound pressure generated by the first vibration generating module.

[0267] According to some examples of the present application, the system may further include a sealing member for sealing the fastening portion of the rear cover box and the rear cover part.

[0268] According to some examples of the present application, the first hole of the rear cover part, the rear cover part and the first vibration generating module form a Helmholtz resonator, which can reduce low-pitched noise characteristics.

[0269] According to some examples of the present application, the side structure of the system rear cover further includes a system rear cover duct formed in at least a portion of the system rear cover, and the system rear cover duct can output the sound pressure generated by the first vibration generating module and the second vibration generating module to the outside.

[0270] According to some examples of the present application, the system rear cover duct can improve the sound pressure generated by the first vibration generating module and the second vibration generating module.

[0271] According to some examples of the present application, the panel guide includes a panel support portion connected to an edge portion of the rear surface of the display panel and supported by the side cover portion, and a guide side wall connected to the panel support portion and wrapping around a side of the side cover portion, and vibration of the second vibration generating module can be transmitted to the edge portion of the display panel via the second portion of the rear cover portion, the side cover portion, and the panel support portion.

[0272] According to some examples of the present application, the display module further includes a backlight unit arranged between the rear cover portion and the display panel, the backlight unit including a reflective sheet arranged on the first and second rear cover portions of the rear cover, a light guide plate arranged on the reflective sheet, and a plurality of optical sheets arranged on the light guide plate, and vibration of the second vibration generating module can be transmitted to an edge portion of the display panel via the second rear cover portion, the side cover portion, and the panel support portion.

[0273] A display device according to one example of the present application may include a display module having a display panel for displaying images, a panel guide supporting an edge portion of the rear of the display panel, a rear (back) cover supporting the panel guide and covering the rear of the display module, a first vibration generating module disposed in a middle portion of the rear cover for generating sound in a first sound range band in the middle portion of the display panel, and a second vibration generating module disposed in an edge portion of the rear cover for generating sound in a second sound range band different from the first sound range band in the edge portion of the display panel.

[0274] According to some examples of the present application, the first range band can be lower than the second range band.

[0275] According to some examples of the present application, the display device may further include a system back cover that houses the display module, the panel guide, the back cover, the first vibration generating module and the second vibration generating module, and the system back cover may include a back structure that covers the back of the display device and a side structure provided at an edge of the back structure.

[0276] According to some examples of the present application, the rear structure of the system rear cover further includes a system rear cover box that is fastened to the rear cover part and seals the first vibration generating module and the first hole of the rear cover part, and the system rear cover box can improve the sound pressure generated by the first vibration generating module.

[0277] According to some examples of the present application, the system may further include a sealing member for sealing the fastening portion of the rear cover box and the rear cover part.

[0278] A display device according to one example of the present application includes a display module including a display panel for displaying images, a rear (back) cover arranged on the rear of the display module, a first vibration generating module arranged in a first rear area of ​​the rear cover, and a second vibration generating module arranged in a second rear area of ​​the rear cover, and the rear cover includes a first hole overlapping with the first vibration generating module and a second hole overlapping with the second vibration generating module.

[0279] According to some examples of the present application, a first rear region of the rear cover may overlap a middle or end (edge ​​or near end) portion of the display module, and a second rear region of the rear cover may overlap a middle and end portion of the display module excluding the first rear region.

[0280] According to some examples of the present application, the display device outputs a first sound in a first sound range band based on vibration of a first vibration generating module, and outputs a second sound in a second sound range band based on vibration of a second vibration generating module, where the first sound range band may be different from the second sound range band.

[0281] According to some examples of the present application, the rear cover may be arranged on the rear of the display module and further include a rear cover part supporting the first vibration generating module and the second vibration generating module, and the rear cover part may include a first hole formed in the first rear region and a second hole formed in the second rear region.

[0282] According to some examples of the present application, the first vibration generating module can vibrate independently of the vibration of the rear cover part, and the second vibration generating module can vibrate independently of the vibration of the rear cover part.

[0283] According to some examples of the present application, a first rear region of the rear cover overlaps a middle portion of the display module, and a second rear region of the rear cover overlaps an end portion of the display module, and the rear cover is disposed on the rear of the display module and includes a rear cover part supporting a first vibration generating module and the second vibration generating module, and may further include a hole part formed in the rear region of the rear cover part between the first vibration generating module and the second vibration generating module.

[0284] According to some examples of the present application, the rear cover portion, the hole portion and the first vibration generating module can form a Helmholtz resonator.

[0285] According to some examples of the present application, a display device according to one example of the present application may further include a system back cover disposed on the back of the back cover, where a first back area of ​​the back cover overlaps with a middle portion of the display module and a second back area of ​​the back cover overlaps with an end portion of the display module, and the system back cover may include a system back cover box that seals a surrounding space of the first vibration generating module.

[0286] According to some examples of the present application, the system back cover may include a back structure disposed on a back side of the back cover, a side structure connected to an edge of the back structure and covering a side of the display module, and a system back cover duct formed in at least a portion of the side structure.

[0287] According to some examples of the present application, the rear cover is arranged on the rear of the display module, further includes a rear cover part supporting the first vibration generating module and the second vibration generating module, and further includes a hole part formed in a rear area between the first vibration generating module and the second vibration generating module of the rear cover part, and a system rear cover box can accommodate the first vibration generating module and the hole part.

[0288] According to some examples of the present application, a display device according to one example of the present application may further include a panel guide supported by the rear cover for supporting a rear edge portion of the display panel, and the display module may further include a backlight unit supported by the rear cover and disposed on the rear of the display panel, and the backlight unit may include a reflective sheet disposed on the rear cover and covering the first hole and the second hole, a light guide plate disposed on the reflective sheet, and an optical sheet portion disposed on the light guide plate.

[0289] According to some examples of the present application, the rear cover may be disposed on the rear of the display module and further include a rear cover portion supporting the first vibration generating module and the second vibration generating module, and the rear cover portion may include a cross-sectional structure having a concave curved shape.

[0290] According to some examples of the present application, a display device according to one example of the present application may further include a panel guide supported by the rear cover for supporting a rear edge portion of the display panel, and the display module may further include a backlight unit arranged between the display panel and the rear cover portion, and the backlight unit may include a reflective sheet arranged on the rear cover portion and covering the first hole and the second hole, a light guide plate arranged on the reflective sheet, an optical sheet portion arranged on the light guide plate, and an air gap provided between the reflective sheet and the light guide plate.

[0291] According to some examples of the present application, the reflective sheet may be disposed on the rear cover portion so as to have a conformal shape that follows the shape of the rear cover portion, and the light guide plate may be disposed on the reflective sheet so as to have a non-conformal shape that does not follow the shape of the rear cover portion.

[0292] A display device according to one example of the present application may include a display module including a display panel for displaying images, a rear cover further including a rear cover part covering the rear of the display module, and a first vibration generating module and a second vibration generating module arranged on both the rear cover part and vibrating the display module, a first gap arranged between the first vibration generating module and the display module of the rear cover part, and a second gap arranged between the second vibration generating module and the display module.

[0293] According to some examples of the present application, the rear cover portion may include a first hole that provides a first gap between the first vibration generating module and the display module, and a second hole that provides a second gap between the second vibration generating module and the display module.

[0294] According to some examples of the present application, the display module further includes a backlight unit disposed between the display panel and the rear cover portion, the rear cover portion including a structure having a concavely curved shape in a cross-sectional view, and the backlight unit may include a reflective sheet disposed on the rear cover portion and covering the first gap and the second gap, a light guide plate disposed on the reflective sheet, an optical sheet portion disposed on the light guide plate, and an air gap provided between the reflective sheet and the light guide plate.

[0295] According to some examples of the present application, the first vibration generating module may include an acoustic generating unit including a bobbin and a coil wound on the bobbin, and the bobbin of the acoustic generating unit may be coupled to the rear cover around the first hole.

[0296] According to some examples of the present application, the first vibration generating module includes an acoustic generating unit including a bobbin and a coil wound on the bobbin, and the bobbin of the acoustic generating unit can have a size that can be received in the first hole.

[0297] According to some examples of the present application, the first vibration generating module is connected to the rear cover via a connecting member, and the thickness of the connecting member may be 1 to 4 times the thickness of the rear cover.

[0298] According to some examples of the present application, the second vibration generating module may include a piezoelectric vibration unit having a piezoelectric element.

[0299] According to some examples of the present application, the second vibration generating module may include a piezoelectric vibration unit having a piezoelectric element, the piezoelectric vibration unit may include a base plate connected to the rear cover to cover the second hole, and the piezoelectric element may be disposed on the base plate.

[0300] According to some examples of the present application, the piezoelectric vibration unit may further include a cover plate coupled to the piezoelectric element, and the piezoelectric element and the cover plate may have a size smaller than a size of the second hole.

[0301] According to some examples of the present application, the first vibration generating module may overlap one of the middle and end portions of the display module, and the second vibration generating module may overlap the remaining one of the middle and end portions of the display module.

[0302] According to some examples of the present application, the display module includes first and second end portions aligned alongside each other and third and fourth end portions aligned alongside each other, the second vibration generating module includes a first piezoelectric vibration unit overlapping with the first end portion of the display module and a second piezoelectric vibration unit overlapping with the second end portion of the display module, and the first vibration generating module includes first and second acoustic generating units arranged adjacent to the first and second piezoelectric vibration units, respectively.

[0303] According to some examples of the present application, the second vibration generating module may further include at least one of a third piezoelectric vibration unit overlapping with a third end portion of the display module, a fourth piezoelectric vibration unit overlapping with a fourth end portion of the display module, and a fifth piezoelectric vibration unit overlapping with a central portion of the display module.

[0304] According to some examples of the present application, the display module includes first and second end portions aligned side by side, and third and fourth end portions aligned side by side, the first vibration generating module includes a first acoustic generating unit overlapping with the first end portion of the display module and a second acoustic generating unit overlapping with the second end portion of the display module, and the second vibration generating module includes at least one of a first piezoelectric vibration unit overlapping with a central portion of the display module, a second piezoelectric vibration unit overlapping with the third end portion of the display module, and a third piezoelectric vibration unit overlapping with the fourth end portion of the display module.

[0305] According to some examples of the present application, the display module includes first and second end portions aligned alongside each other and third and fourth end portions aligned alongside each other, the first vibration generating module includes an acoustic generating unit overlapping a central portion of the display module, and the second vibration generating module includes a first piezoelectric vibration unit overlapping the first end portion of the display module and a second piezoelectric vibration unit overlapping the second end portion of the display module.

[0306] According to some examples of the present application, the second vibration generating module may further include at least one of a third piezoelectric vibration unit overlapping with a third end portion of the display module and a fourth piezoelectric vibration unit overlapping with a fourth end portion of the display module.

[0307] The features, structures, effects, etc. described in the above examples of the present application are included in at least one example of the present application, and are not necessarily limited to only one example. Furthermore, the features, structures, effects, etc. exemplified in at least one example of the present application can be combined or modified in different examples by a person having ordinary skill in the art to which the present application belongs. Therefore, the contents related to these combinations and modifications must be interpreted as being included in the scope of the present application.

[0308] The present application described above is not limited to the above-mentioned embodiments and the attached drawings, and it will be apparent to those skilled in the art to which the present application pertains that multiple substitutions, modifications and changes are possible within the scope of the technical matters of the present application. Therefore, the scope of the present application is defined by the claims set forth below, and all modifications or alterations derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present application. [Explanation of symbols]

[0309] 100: Display module 110: Display panel 130: Backlight unit 200: Panel Guide 300: Rear cover 310: Rear cover part 311: Rear cover hole 313: 1st Hall 315: 2nd Hall 400: First vibration generating module 410, 430: Sound generating unit 500: Second vibration generating module 501: Base plate 503: Piezoelectric element 505: Cover plate 510, 530: Piezoelectric vibration unit 600: System back cover 611: System back cover box 631: System rear cover duct 800: Second connecting member

Claims

1. a display module including a display panel and configured to display an image; a back cover on the back of the display module; a first vibration generating device in a first rear region of the rear cover and configured to generate first sound waves; and a second vibration generating device in a second rear region of the rear cover and configured to generate second sound waves different from the first sound waves; the display module is configured to vibrate by one or more of the first sound wave and the second sound wave transmitted from one or more of the first vibration generating device and the second vibration generating device, and to output sound; The display module includes: a first region that vibrates due to the first sound wave transmitted from the first vibration generating device; and A display device comprising a second area that vibrates due to the second sound waves transmitted from the second vibration generating device.

2. The display device according to claim 1 , wherein the display module is configured to output one or more of a first sound based on the first sound wave and a second sound based on the second sound wave.

3. The display device of claim 2 , wherein the first sound range band is different from the second sound range band.

4. the first sound includes frequencies in a low frequency range; and / or The display device according to claim 2 , wherein the second sound includes a frequency in a mid-high frequency range or a high frequency range.

5. 5. The display device according to claim 1, wherein the rear cover includes a rear cover portion that includes the first rear region and the second rear region and is located on the rear of the display module, the rear cover portion being configured to support the first vibration generating device and the second vibration generating device.

6. The rear cover portion is A first hole overlapping the first vibration generating device, and The display device of claim 5 , further comprising a second hole overlapping the second vibration generating device.

7. the first hole is between the first vibration generating device and the display module, The display device according to claim 6 , wherein the second hole is between the second vibration generating device and the display module.

8. The size of the first hole is smaller than the size of the first vibration generator, The display device according to claim 6 or 7, wherein the size of the second hole is smaller than the size of the second vibration generating device.

9. The first vibration generating device is configured to cover the first hole, The display device according to claim 6 , wherein the second vibration generating device is configured to cover the second hole.

10. the first vibration generating device is configured to be connected to the rear cover part so as to cover the first hole, and is configured to include a bobbin and a coil wound around the bobbin; The display device according to claim 6 , wherein the bobbin is configured to be received in the first hole.

11. the first vibration generating device is configured to be connected to the rear cover part so as to cover the first hole, and is configured to include a bobbin and a coil wound around the bobbin; The display device of claim 6 , wherein the bobbin is configured to be coupled to the rear cover portion around the first hole.

12. a first rear region of the rear cover overlapping a middle portion or an edge portion of the display module; The display device of claim 1 , wherein the second rear region of the rear cover overlaps a middle portion and an edge portion of the display module excluding the first rear region.

13. a display module including a display panel and configured to display an image; a back cover on the back of the display module; A first vibration generator configured to vibrate the rear cover; and a second vibration generating device configured to vibrate the rear cover; the display module is configured to vibrate by one or more of the first vibration generating device and the second vibration generating device to output sound; The rear cover is a rear cover portion on the rear side of the display module; A first hole overlapping the first vibration generating device, and A second hole overlapping the second vibration generating device is included, The first vibration generating device is configured to vibrate the rear cover part around the first hole to generate a first sound wave in the first hole, the second vibration generating device is configured to generate a second sound wave in the second hole to vibrate the display module; Display device.

14. The display device according to claim 13 , wherein the second vibration generating device including a piezoelectric vibration element on the rear surface of the rear cover portion is disposed to cover the second hole.

15. The second vibration generating device is a base plate connected to the rear cover portion to cover the second hole; and The display device of claim 13 , further comprising a piezoelectric vibration element on the base plate so as to overlap the second hole.

16. The display device according to claim 14 or 15, wherein the piezoelectric vibration element has a size smaller than a size of the second hole.

17. The display device of claim 13 , wherein the first vibration generating device is configured to be connected to the rear cover portion so as to cover the first hole, and is configured to include a bobbin and a coil wound around the bobbin.

18. The display module includes: a first edge portion and a second edge portion that are parallel to each other; and further including a third edge portion and a fourth edge portion parallel to one another; The second vibration generating device is a first piezoelectric vibration element overlapping the first edge portion of the display module; and a second piezoelectric vibrating element overlapping the second edge portion of the display module; The display device according to claim 13 , wherein the first vibration generating device includes a first sound generating device and a second sound generating device adjacent to the first piezoelectric vibration element and the second piezoelectric vibration element, respectively.

19. The second vibration generating device is a third piezoelectric vibration element overlapping the third edge portion of the display module; a fourth piezoelectric vibration element overlapping the fourth edge portion of the display module; and The display device of claim 18 , further comprising one or more fifth piezoelectric vibrating elements overlapping a middle portion of the display module.

20. The display module includes: a first edge portion and a second edge portion that are parallel to each other; and further including a third edge portion and a fourth edge portion parallel to one another; The first vibration generating device is a first sound-generating device overlapping the first edge portion of the display module; and a second sound-generating device overlapping the second edge portion of the display module; The second vibration generating device is a first piezoelectric vibration element overlapping a middle portion of the display module; a second piezoelectric vibration element overlapping the third edge portion of the display module; and 18. The display device of claim 13, further comprising one or more third piezoelectric vibrating elements overlapping the fourth edge portion of the display module.

21. The display module includes: a first edge portion and a second edge portion that are parallel to each other; and further including a third edge portion and a fourth edge portion parallel to one another; The first vibration generating device is a sound-generating device overlapping a middle portion of the display module; The second vibration generating device is a first piezoelectric vibration element overlapping the first edge portion of the display module; and 18. The display device of claim 13, further comprising a second piezoelectric vibrating element overlapping the second edge portion of the display module.

22. The second vibration generating device is a third piezoelectric vibration element overlapping the third edge portion of the display module; and The display device of claim 21 , further comprising one or more fourth piezoelectric vibrating elements overlapping the fourth edge portion of the display module.

23. The display device according to claim 1 , wherein the rear cover includes a hole portion in a rear area between the first vibration generator and the second vibration generator.

24. the display module further includes a backlight unit between the display panel and the rear cover; The backlight unit is configured to vibrate by one or more of the vibrations of the first vibration generating device and the second vibration generating device, The display device according to claim 1 , wherein the display panel is configured to vibrate in response to vibration of the backlight unit and to output sound.

25. The display device of claim 24, wherein the display module further comprises a panel vibration space between the display panel and the backlight unit.

26. The backlight unit comprises: a reflective sheet on the rear cover to receive one or more of the vibrations of the first vibration generating device and the vibrations of the second vibration generating device; a light guide plate on the reflective sheet; an optical sheet portion on the light guide plate; and 26. The display device of claim 24 or 25, comprising an air gap between the reflective sheet and the light guide plate.

27. 27. The display device of claim 1, wherein the display panel acts as a diaphragm for outputting the sound.

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