DISPLAY DEVICE INCLUDING HINGE DEVICE FOR CONTROLLING STATE THEREOF

A display device according to an aspect of the present disclosure may include a display module; and a hinge component configured to enable the display module to switch between being in a flat state or a curved state. The hinge component includes at least one hinge frame; at least one hinge component around which the at least one hinge frame is configured to rotate to allow the display module to switch between the flat state and the curved state; and at least one stopper at each of two ends of the hinge component configured to maintain the display module in the flat state, the curved state, or an intermediary state in between the flat state and the curved state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Korean Patent Application No. 10-2023-0109053 filed on Aug. 21, 2023, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

Field of Disclosure

The present disclosure relates to a display device, and more particularly, to a bendable display device.

Description Of Related Background

In general, examples of flat display devices include liquid crystal display devices, plasma display devices, field emission display devices, light-emitting display devices. The liquid crystal display device and the light-emitting display device are in the limelight because the liquid crystal display device and the light-emitting display device have advantages in mass-production technologies, ease of operations, and implementation of high image quality.

Recently, there has been a particular need for research and development on technical aspects of flat display devices, as well as research and development on the design of products to make the products more appealing to customers. Therefore, there has been a gradual increase in the need for curved display devices with curvatures.

In particular, recently panels have gradually become larger in size. Accordingly, the development is being conducted on innovative curvature-changeable display devices with slimness required by consumers.

SUMMARY

An example objective of the present disclosure is to provide a display device capable of allowing a user to arbitrarily change curvatures between a flat display mode and a curved display mode.

Another example objective of the present disclosure is to provide a display device capable of stably maintaining a curvature in a curved display mode.

The concepts described herein are not limited to example objectives mentioned above and may encompass other objectives as understood by those skilled in the art from the following descriptions.

The present disclosure may provide the display device capable of allowing the user to arbitrarily change the curvature between the flat display mode and the curved display mode.

The present disclosure may provide the display device capable of being stably maintaining the curvature while suppressing noise and abrasion of the constituent components caused by repeated bending.

In one aspect, a display device includes a display module; and a hinge component configured to enable the display module to switch between being in a flat state or a curved state. The hinge component includes at least one hinge frame; at least one hinge component around which the at least one hinge frame is configured to rotate to allow the display module to switch between the flat state and the curved state; and at least one stopper at each of two ends of the hinge component configured to maintain the display module in the flat state, the curved state, or an intermediary state in between the flat state and the curved state.

In another aspect, the display device further includes a pair of bolt and nut for each of the at least one hinge component, the pair of bolt and nut being configured to allow for adjustment of torque applied for maintaining the flat state, the curved state, and the intermediary state.

In another aspect, the at least one stopper includes a pair of a lower stopper and an upper stopper.

In another aspect, each of the lower stopper and the upper stopper includes a fixing portion; and a slit, wherein the slit and the fixing portion are configured to maintain the display module in the flat state, the curved state, or the intermediary state in between the flat state and the curved state.

In another aspect, the slit has an elongated semi-circular shape.

In another aspect, the fixing portion is configured to move in a first direction that is perpendicular to a direction in which the display module moves between the flat state and the curved state.

In another aspect, the display device further includes an embossed portion, wherein the slit is formed around the embossed portion.

In another aspect, the fixing portion and the embossed portion are configured to move in a first direction that is perpendicular to a direction in which the display module moves between the flat state and the curved state.

In another aspect, the at least one hinge frame includes multiple independently movable hinge frames each of which can rotate around one or more of the at least one hinge component to enable the display module to switch between the flat state and the curved state.

In another aspect, the display device further includes a hinge cover configured to cover the hinge component; and a pair of handles, each of which is coupled to one end of the hinge cover for moving the display module between the flat state and the curved state.

In one aspect, a device includes a plurality of parts coupled together via a plurality of hinges to enable moving a display module between a flat state and a curved state, wherein the plurality of parts are independently movable; and at least one stopper attached to the plurality of parts, the at least one stopper being configured to maintain the display module in the flat state, the curved state, or an intermediary state in between the flat state and the curved state.

In another aspect, the plurality of parts includes a first part at a right end of the device; a second part at a left end of the device; a middle part at a center of the device; a third part between the middle part and the first part; and a fourth part between the middle part and the second part.

In another aspect, the at least one stopper includes a first stopper attached to the first part; a second stopper attached to the second part; a third stopper attached to the third part; and a fourth stopper attached to the fourth part.

In another aspect, each of the first stopper, the second stopper, the third stopper, and the fourth stopper includes a pair of stoppers.

In another aspect, the at least one stopper is formed as an extension of a respective outer end of each of the first part and the second part.

In another aspect, the respective outer end is bent to form the at least one stopper.

In another aspect, the at least one stopper includes a slit formed on the at least one stopper; and a fixing portion surrounded by the slit and configured to move in a first direction that is perpendicular to a direction in which the display module moves between the flat state and the curved state.

In another aspect, the device is coupled to a backend of the display module to move the display module between the flat state and the curved state.

In another aspect, a pair of handles are attached to ends of the device to enable moving the display module between the flat state and the curved state.

In another aspect, the device is coupled to a stand for holding the display module.

In another aspect, the lower stopper and the upper stopper have a horizontally symmetric structure, and wherein the pair of stoppers has a vertically symmetry with respect to at least one other pair of stoppers of the hinge component.

In another aspect, an outer end of the first part is bent upward and downward to define a pair of support portions, wherein each support portion of the pair of support portions has a rectangular shape, and wherein a first slot is formed in the support portion and has a shape elongated in a longitudinal direction.

In another aspect, a polymer plate is disposed on an upper portion of the support portion, and the at least one stopper is disposed on an upper portion of the polymer plate.

In another aspect, the polymer plate has a rectangular shape, and a second slot is formed in the polymer plate and has a shape elongated in a longitudinal direction, wherein the second slot is positioned to correspond to the first slot, and wherein the second slot is larger in size than the first slot.

In another aspect, circular first holes are provided in the polymer plate and disposed at predetermined intervals in a longitudinal direction to define the second slot, wherein the second slot includes the circular first holes and a plurality of second holes provided between the plurality of first holes, and wherein the second hole has a smaller width than the first hole.

In another aspect, in case of the curved state, an embossed portion is positioned in the first hole in a predetermined curvature state, such that the embossed portion is inserted and fixed into the first hole, and wherein in case the flat state or the intermediary state is implemented, the embossed portion is positioned in the second hole, such that the embossed portion is lifted upward and positioned on the polymer plate without being inserted and fixed into the second hole.

In another aspect, the device further includes a link attached to upper portions of the pair of stoppers in a direction in which the link traverses the pair of stoppers, wherein the link is attached to the upper portion of the fixing portion opposite to the embossed portion.

In another aspect, the device further includes a plurality of protruding structures protruding from a rear surface of the display module, wherein insertion holes are provided at two opposite ends of the link, and the protruding structures are inserted into the insertion holes.

In another aspect, the protruding structure is disposed on the rear surface of the display module and has a height to a degree to which the protruding structure penetrates the insertion hole, and wherein the plurality of protruding structures is disposed at intervals between the plurality of first holes.

According to the present disclosure, the protruding structure, the display cover, the stopper, and the third hinge frame may be integrated, like a unified material. Therefore, the component material may be simplified and unified.

DETAILED DESCRIPTION

The features of various embodiments of the present disclosure may be partially or entirely adhered to or combined with each other and may be interlocked and operated in technically various ways, and the embodiments may be carried out independently of or in association with each other.

Hereinafter, an exemplary aspect of the present disclosure will be described in detail with reference to the drawings.

FIG.1is a block diagram illustrating a display device according to some aspects of the present disclosure.

With reference toFIG.1, a display device100may include a tuner part101, a demodulation part102, a storage part103, an external device interface part104, a network interface part105, a user input interface part106, and a control unit107.

In addition, the display device100may include a display module110, a display deformation drive part120, an audio output part108, and a power supply part109.

Further, the display device100may further include a 3D viewing device130. However, the present disclosure is not limited thereto. In some instances, the 3D viewing device130may not be included.

The tuner part101may select a radio frequency (RF) broadcast signal, which corresponds to a channel selected by a user or all pre-stored channels, from RF broadcast signals received through an antenna. In addition, the tuner part may convert the selected RF broadcast signal into an intermediate frequency signal, a baseband image, or a voice signal.

For example, when the selected RF broadcast signal is a digital broadcast signal, the selected RF broadcast signal may be converted into a digital IF signal (DIF). When the selected RF broadcast signal is an analog broadcast signal, the selected RF broadcast signal may be converted into an analog baseband image or a voice signal (CVBS/SIF). That is, the tuner part101may process the digital broadcast signal or the analog broadcast signal. The analog baseband image or voice signal (CVBS/SIF) outputted from the tuner part101may be inputted directly to the control unit107.

In addition, the tuner part101may receive a RF broadcast signal of a single carrier according to the advanced television system committee (ATSC) method or receive RF broadcast signals of a plurality of carriers according to the digital video broadcasting (DVB) method.

The demodulation part102may receive the digital IF signal (DIF), which is converted by the tuner part101, and perform a demodulation operation.

For example, in case that the digital IF signal outputted from the tuner part101is the ATSC type, the demodulation part102performs 8-vestigial side band (8-VSB) demodulation. In addition, the demodulation part102may also perform channel decryption.

In addition, for example, when the digital IF signal outputted from the tuner part101is the DVB type, the demodulation part102may perform coded orthogonal frequency division modulation (COFDMA). In addition, the demodulation part102may also perform channel decryption.

In addition, the demodulation part102may output a stream signal (TS) after performing the demodulation and the channel decryption.

Meanwhile, the demodulation parts102may be separately provided as an ATSC type demodulation part and a DVB type demodulation part. For example, an ATSC demodulation part and a DVB demodulation part may be provided.

The stream signal outputted from the demodulation part102may be inputted to the control unit107.

After the control unit107performs demultiplexing, image/voice signal processing, and the like, the control unit107may output an image to the display module110and output a voice to the audio output part108.

The external device interface part104may connect an external device and the display device100. To this end, the external device interface part104may include an A/V input/output part (not illustrated) or a wireless communication part (not illustrated).

The external device interface part104may be connected to external devices, such as digital versatile disks (DVDs), Blu rays, gaming devices, cameras, camcorders, computers, and the like in a wired/wireless manner. For example, the external device interface part104may transmit images, voices, or data signals, which are inputted from the outside through the connected external device, to the control unit107of the display device100.

In addition, images, voices, or data signals processed by the control unit107may be outputted to the connected external device. To this end, the external device interface part104may include the A/V input/output part or the wireless communication part.

The external device interface part104may transmit and receive data to and from the 3D viewing device130.

The network interface part105may provide an interface for connecting the display device100to wired/wireless networks including the Internet. The network interface part105may be equipped with an Ethernet terminal or the like to be connected to the wired network. The network interface part105may use wireless LAN (WLAN), wireless broadband (Wibro), world interoperability for microwave access (WiMAX), and high-speed downlink packet access (HSDPA) communication standards to be connected to the wireless network.

In addition, the network interface part105may receive, through the network, content or data provided by the Internet, a content provider, or a network operator.

The storage part103may store programs for processing and controlling signals in the control unit107or store signal-processed images, voices, or data signals.

In addition, the storage part103may serve to temporarily store images, voices, or data signals to be inputted to the external device interface part104. The storage part103may also store information on a predetermined broadcast channel through a channel memory function such as a channel map.

FIG.1illustrates an aspect in which the storage part103and the control unit107are separately provided. However, the scope of the present disclosure is not limited thereto. The storage part103may be included in the control unit107.

The user input interface part106may transmit a signal, which is inputted by the user, to the control unit107or transmit a signal from the control unit107to the user.

For example, the user input interface part106may receive user input signals, such as power on/off, channel selection, and screen configurations, from a remote control device or transmit signals from the control unit107to the remote control device in accordance with various communication methods such as a radio frequency (RF) communication method or an infrared (IR) communication method.

The control unit107may use the tuner part101, the demodulation part102, and the external device interface part104to generate and output signals for outputting images or voices by demultiplexing the inputted stream signals or processing demultiplexed signals.

In addition, image signals processed by the control unit107may be inputted to the display module110, such that images corresponding to the corresponding image signals may be displayed. The image signal processed by the control unit107may be inputted to an external output device through the external device interface part104.

The voice signal processed by the control unit107may be outputted as a sound to the audio output part108. The voice signal processed by the control unit107may be inputted to the external output device through the external device interface part104.

In addition, the control unit107may control overall operations of the display device100.

The display module110may generate driving signals by converting an image signal, a data signal, an OSD signal, a control signal, and the like, which are processed by the control unit107or converting an image signal, a data signal, a control signal, and the like received by the external device interface part104.

Aspects of the present disclosure provide examples in which the display device100may be deformed to have the display module110in a flat state, i.e., a flat display mode, or a curved state, i.e., a curved display mode. In case that the display module110is deformed to be in the curved state (or curved surface state) as if the display module110surrounds the user positioned in front of the display module110, the display module110may provide the user with realistic image quality and immersion. For example, the display device100may be implemented by an OLED panel. However, the present disclosure is not limited thereto.

The display module110may be configured to provide a three-dimensional image to the user. For viewing three-dimensional images, the display module110may be classified into an additional display type display module and a single display type display module.

The single display type display module110may implement 3D images without the separate 3D viewing device130, for example, via 3D glasses or the like (e.g., various modules, such as a lenticular type or a parallax barrier, may be applied).

The additional display type display module may implement 3D images by using the 3D viewing device130in addition to the display module110. For example, various modules, such as a head mount display (HMD) type or a glass type, may be applied.

Meanwhile, the display module110may include a touch screen and can be used as an input device as well as an output device.

The display deformation drive part120may be configured to deform the display module110in a flat state or a curved state (or curved surface state).

In the present disclosure, the curvature of the display module110may be arbitrarily changed between the flat display mode and the curved display mode. In the flat display mode, the display module110may be implemented in a flat state. In the curved display mode, the display module110may be implemented in a curved state.

For example, the display deformation drive part120may be configured to deform the display module110by applying a physical force directly or indirectly to the display module110.

The audio output part108may receive a signal processed by the control unit107, e.g., a stereo signal, a 3.1-channel signal, or a 5.1-channel signal and output a voice. The audio output part108may be implemented as various types of speakers.

The power supply part109may supply corresponding power to the overall components of the display device100.

Examples of the display device100disclosed in the present disclosure may include a TV set, a mobile phone, a smartphone, a notebook computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), and the like.

A block diagram of the display device100illustrated inFIG.1is a block diagram for different aspects of the present disclosure described below. Therefore, the constituent elements in the block diagram may be integrated, added, or excluded depending on the specifications of the display device100implemented. For example, as necessary, two or more constituent elements may be integrated into a single constituent element, or one constituent element may be divided into two or more constituent elements. In addition, the functions, which are performed in each block, are provided to explain the embodiments of the present disclosure. The specific operations or devices do not limit the protection scope of the present disclosure.

FIG.2is a block diagram schematically illustrating the display module inFIG.1according to some aspects of the present disclosure.

With reference toFIG.2, the display module110may include a display panel111including a plurality of subpixels, and a drive circuit part112configured to supply various types of signals to the display panel111.

The display panel111may be configured to display images to the user and include a plurality of subpixels SP. In the display panel111, the plurality of scan lines SL and the plurality of data lines DL may intersect one another, and each of the plurality of subpixels SP may be connected to the scan line SL and the data line DL. In addition, the plurality of subpixels SP may each be connected to a high-potential power line, a low-potential power line, a reference line, or the like. However, the present disclosure is not limited thereto.

The display panel111may have a display area, and a non-display area configured to surround the display area.

The display area is an area of the display panel111in which images are displayed.

The display area may include a plurality of subpixels configured to constitute a plurality of pixels, and a circuit configured to operate the plurality of subpixels. The plurality of subpixels is minimum units that constitute the display area. The n subpixels may constitute a single pixel. All types of display panels, such as liquid crystal display panels, organic electroluminescent display panels, quantum dot display panels, and electroluminescent display panels, may be used as the display panel111are within the scope of the present disclosure.

The non-display area is an area in which no image is displayed. The non-display area may be defined as an area extending from the display area. The non-display area may include link lines and pad electrodes for transmitting signals to the subpixels in the display area. Alternatively, the non-display area may include drive ICs such as gate drivers IC and data drivers IC.

The drive circuit part112operates the display panel111in response to a control signal supplied from the control unit107inFIG.1. To this end, the drive circuit part112may include a timing controller112-1, a gate drive part112-2, and a data drive part112-3.

For example, the gate drive part112-2may supply a plurality of scan signals to the plurality of scan lines in response to a plurality of gate control signals provided from the timing controller112-1.FIG.2illustrates that the single gate drive part112-2is disposed to be spaced apart from the left side of the display panel111. However, the number and arrangement of the gate drive part112-2are not limited thereto.

For example, the data drive part112-3may convert image data, which are inputted from the timing controller112-1, into a data voltage by using a reference gamma voltage in response to a plurality of data control signals provided from the timing controller112-1. The data drive part112-3may supply the converted data voltage to the plurality of data lines.

In addition, the timing controller112-1may align image data, which are inputted from the outside, and supply the image data to the data drive part112-3. The timing controller112-1may generate the gate control signals and the data control signals by using synchronizing signals, i.e., dot clock signals, data enable signals, and horizontal/vertical synchronizing signals inputted from the outside. Further, the timing controller112-1may control the gate drive part112-2and the data drive part112-3by supplying the generated gate control signals and data control signals to the gate drive part112-2and the data drive part112-3.

FIG.3is a perspective view illustrating a display device according to some aspects of the present disclosure.

FIG.4is a rear view illustrating the display device according to some aspects of the present disclosure.

FIG.5is a perspective view illustrating a hinge unit inFIG.4according to some aspects of the present disclosure.

FIG.3is a perspective view illustrating a rear surface of the display device100according to some aspects of the present disclosure including a stand115, a hinge cover121, and a stand fastening part124.

FIG.4is a view illustrating the rear surface of the display device100according to the first aspect of the present disclosure that does not include the stand115, the hinge cover121, and the stand fastening part124. For convenience of description,FIG.4illustrates a state in which the left side of a hinge unit122is excluded. A hinge unit may also be referred to as a hinge device.

With reference toFIGS.3to5, the display device100may include the display module110, the stand115, and the display deformation drive part120.

The display deformation drive part120may include the hinge unit122configured to deform the display module110to the flat state or the curved state, and the hinge cover121configured to cover the hinge unit122.

The display module110is a constituent element for providing an image and a sound to the user. To this end, various types of components for providing the image and the sound may be mounted in the display module110.

The display module110may include a display panel and a display cover113.

The display panel may be configured to display images to the outside and configured as various displays for displaying images. That is, the display panel may be a flat panel display and provided as any one of a plasma display panel, a liquid crystal display, an organic light-emitting diode display, and a light-emitting diode display. For example, in case that the flat panel display is a liquid crystal display, the display module110may include a liquid crystal panel configured to display images, a backlight unit configured to supply light to the liquid crystal panel, the display cover, and the like. In addition, in case that the flat panel display is an organic light-emitting diode display, the display module110may include an organic light-emitting diode panel configured to display images, the display cover, and the like.

Meanwhile, for example, the display panel may be provided as a curved display or a flexible display instead of a flat panel display. In addition, the display panel maybe provided as a touch type display.

The display cover113is a constituent element configured to cover the display panel. The display cover113may be provided as a single cover or a plurality of covers. For example, in case that the display cover is provided as a plurality of covers, the display covers113may include a decorative cabinet, a cover bottom, a back cover, and the like. However, the present disclosure is not limited thereto.

A stand mounting hole for mounting the stand115may be formed in a rear surface of the display cover113.

In addition, various interface cables, such as a power cable for providing power to the display module110and a cable for providing a sound, may be provided on the rear surface of the display cover113.

Although not illustrated, a heat dissipation part may be provided on the rear surface of the display cover113and disposed below the stand mounting hole to dissipate heat in the display module110. The heat dissipation part may be formed in a direction facing a front surface of a stand body115-1of the stand115. Therefore, the heat dissipation part may be disposed so as not to be exposed to the outside of the display device100.

The stand115is a constituent element for supporting the display module110.

The stand115may be mounted rearward of the display module110and seated on a desk, a table, or the like. The stand115may stably support the display module110. For example, the stand115may be disposed rearward of the display module110and mounted on a rear surface of the stand fastening part124. However, the present disclosure is not limited thereto.

The stand115may include the stand body115-1and a stand base115-2.

The stand body115-1may be mounted rearward of the display module110. For example, the stand body115-1may be disposed rearward of the display module110and disposed in a height direction of the display module110.

For example, the stand body115-1may include a front cover, a body base, and a rear cover.

In addition, for example, the stand base115-2may be connected to a lower side of the stand body115-1and seated on a desk, a table, or the like. In this case, the stand base115-2may be detachably connected to the lower side of the stand body115-1. Therefore, in some aspects of the present disclosure, when the product is shipped, the stand base115-2may be separated from the stand body115-1for transportation and delivery to an end user or the like.

For example, the stand base115-2may be made of a metallic material. This configuration is implemented in consideration of design and rigidity. The stand base115-2made of a metallic material may implement an aesthetic external appearance design of the display device100and ensure the support rigidity.

Meanwhile, the display deformation drive part120is a constituent element for adjusting an angle of the display module110to provide an optimal angle when the user or the like uses the display device100. In addition, the display deformation drive part120may connect the display module110and the stand115.

The display deformation drive part120may include the hinge unit122configured to deform the display module110to the flat state or the curved state (or curved surface state), and the hinge cover121configured to cover the hinge unit122.

As described above, the hinge unit122may deform the display module110to the flat state or the curved state, thereby implementing free-stop bending in the curved state.

For example, the hinge unit122may include a 4-torque hinge structure to implement the free-stop bending. For example, the hinge unit122may include a first hinge frame126-1, second hinge frames126-2, third hinge frames126-3, first hinge parts125-1, second hinge parts125-2, and a plurality of stoppers140. However, the present disclosure is not limited thereto. The first hinge part125-1may be an inner hinge part, and the second hinge part125-2may be an outer hinge part.

For example, one second hinge frame126-2may be coupled to either side of one first hinge frame126-1by means of the first hinge part125-1. The coupling may be such that the second hinge frame126-2is movable (can rotate) with respect to the first hinge part125-1.

For example, one third hinge frame126-3may be coupled to an outer end of each of the second hinge frames126-2by means of the second hinge part125-2. The coupling may be such that the second hinge frame126-3is movable (can rotate) with respect to the second hinge part125-2.

Torque may be generated by the first hinge part125-1and the second hinge part125-2. For example, a torque level may be adjusted by adjusting a surface frictional force between the components fastened to bolts127and nuts129provided in the first hinge part125-1and the second hinge part125-2. For example, torque may be increased by tightening the bolt127and the nut129, and torque may be decreased by loosening the bolt127and the nut129. A detailed description of this configuration will be described below.

For example, the pair of stoppers140may be respectively coupled to outer ends of the third hinge frames126-3. For example, when the display device100is viewed from the rear side, the stoppers140may be respectively disposed at upper and lower sides of the outer ends of the third hinge frames126-3one by one. However, the present disclosure is not limited thereto. The number and positions of the stoppers140may be adjusted by a magnitude of a force applied to unfold the display module110in a reverse direction (to the bending direction).

Hereinafter, for convenience of description, the upper and lower sides mean upper and lower sides when viewed from the rear side in a state in which the display device100stands upright.

The stopper140according to one aspect of the present disclosure may serve to restrict (block) a force applied to unfold the display module110in the reverse direction in the curved state. A detailed description of this configuration will be described below.

As described above, the hinge unit122according to the first aspect of the present disclosure may include the single first hinge frame126-1, the two second hinge frames126-2, the two third hinge frames126-3, the two first hinge parts125-1, the two second hinge parts125-2, and the two pairs of stoppers140. However, the present disclosure is not limited thereto.

Meanwhile, the hinge cover121may cover and protect the hinge unit122, i.e., the first hinge frame126-1, the second hinge frames126-2, the third hinge frames126-3, the first hinge parts125-1, the second hinge parts125-2, and the plurality of stoppers140.

The display deformation drive part120may further include the fastening part124fastened to the stand115while covering a central portion of the hinge cover121.

The display deformation drive part120may further include handles123provided at two opposite sides of the hinge cover121and configured to allow the user to apply a physical force to arbitrarily deform the display module110to the flat state or the curved state. However, the present disclosure is not limited thereto. For example, the user may pull the two opposite handles123forward or push the two opposite handles123rearward to arbitrarily deform the display module110to the flat state or the curved state in which the display module110has any curvature.

FIG.6is a view exemplarily illustrating free-stop bending made by the hinge unit according to some aspects of the present disclosure.

FIG.7is an enlarged view of the first hinge part inFIG.5according to some aspects of the present disclosure.

FIG.8is a view illustrating a part of a cross-section of the first hinge part inFIG.7according to some aspects of the present disclosure.

FIG.6is a view for explaining free-stop bending made by the hinge unit.FIG.6is a view illustrating the display module110and the hinge unit122on the rear surface of the display module110when viewed from the top side, for example, when the viewer is positioned at the left side.

With reference toFIGS.6to8, the display module110may freely switch (or freely stop) between the flat state and the curved state by means of the hinge unit122.

In addition, when the display module110freely switches between the flat state and the curved state by means of the hinge unit122, the user may stop the display module110at a desired point (or desired radius of curvature), and the stoppers (140inFIG.4) may inhibit the display module110from moving to another position.

For example, the curved state of the display module110may be implemented by the first hinge frame126-1, the second hinge frames126-2, the third hinge frames126-3, the first hinge parts125-1, and the second hinge parts125-2. In particular, the curved state of the display module110may be implemented by the first hinge part125-1between the first hinge frame126-1and the second hinge frame126-2and the second hinge part125-2between the second hinge frame126-2and the third hinge frame126-3.

As described above, torque may be generated by the first hinge part125-1and the second hinge part125-2. That is, for example, the torque level may be adjusted by adjusting the surface frictional force between the components fastened to the bolts127and the nuts129provided in the first hinge part125-1and the second hinge part125-2. For example, torque may be increased by tightening the bolt127and the nut129, and torque may be decreased by loosening the bolt127and the nut129.

For example, the display module110may be primarily bent at a first curvature by the first hinge part125-1, and the display module110may be secondarily bent at a second curvature by the second hinge part125-2. The second curvature may be larger than the first curvature.

For example, a plain washer127-1, a spring washer127-2, the first hinge frame126-1, polyoxymethylene POM127-3, and the second hinge frame126-2may be sequentially disposed between the bolt127and the nut129, and the second hinge frame126-2, POM127-3, the first hinge frame126-1, a spring washer127-2, and a plain washer127-1may be disposed in the reverse order at a lower side thereof.

The plain washer127-1and the spring washer127-2may be components having a flat plate shape and a spring shape and configured to be fitted between a head of a screw or the bolt127and the component or structure. The plain washer127-1and the spring washer127-2may be used to reduce friction between the components or more securely tight the bolt127.

The POM127-3is a type of polymer and has excellent rigidity and strength, high durability, and stable properties even at a high-temperature temperature. The POM127-3may be substituted with another material.

In addition, a metal block127-4may be inserted between the second hinge frame126-2and the second hinge frame126-2between the bolt127and the nut129. However, the present disclosure is not limited thereto.

Meanwhile, in the display device of the first aspect of the present disclosure, the plurality of stoppers140is coupled to the outer ends of the third hinge frame126-3and serves to restrict (block) the force applied to unfold the display module110in the reverse direction in the curved state. This configuration will be described in detail with reference toFIGS.9A to9C,10A to10C,11A to11C,12A,12B,13A, and13B.

FIGS.9A to9Care enlarged view of part A inFIG.4according to some aspects of the present disclosure.

FIGS.10A to10Care enlarged perspective views of part A inFIG.4according to some aspects of the present disclosure.

FIGS.11A to11Care views illustrating part A inFIG.4when viewed from the lateral side according to some aspects of the present disclosure.

FIG.12Ais an enlarged view of part B inFIG.9Caccording to some aspects of the present disclosure.

FIG.12Bis a view illustrating a cross-section taken along line C-C′ inFIG.12Aaccording to some aspects of the present disclosure.

FIG.13Ais an enlarged view of part B inFIG.9Caccording to some aspects of the present disclosure.

FIG.13Bis a view illustrating a cross-section taken along line D-D′ inFIG.13Aaccording to some aspects of the present disclosure.

FIGS.9A and10Aillustrate an example of a part of the rear surface of the display device100in a state in which the hinge unit is removed.

FIGS.9B and10Billustrate an example of a part of the rear surface of the display device100including the hinge unit122and excluding the stopper140.FIGS.9C and10Cillustrate an example of a part of the rear surface of the display device100including the hinge unit122.

In addition,FIG.11Ais a view illustrating the display device in a state in which the hinge unit122is removed when viewed from the lower side.FIG.11Bis a view illustrating the display device100including the hinge unit122and excluding the stopper140when viewed from the lower side.FIG.11Cis a view illustrating the display device100including the hinge unit122when viewed from the lower side.

FIGS.12A and12Billustrate an example of a part of the display device100in the curved display mode.FIGS.13A and13Billustrate an example of a part of the display device100in the flat display mode.

The present disclosure may include the 4-torque hinge structure including the inner hinge parts and the outer hinge parts to implement the free-stop bending.

Meanwhile, a curvature defect may occur in case that a curvature retention force (i.e., torque) of the hinge unit cannot withstand the force applied to unfold the display module in the reverse direction. In this case, the force applied to unfold the display module in the reverse direction is opposite to the curvature retention force of the hinge unit.

Therefore, the plurality of stoppers may be coupled to the hinge unit of the present disclosure, e.g., the outer ends of the third hinge frame.

With reference toFIGS.9A to9C,10A to10C,11A to11C,12A,12B,13A, and13B, the hinge unit122may include the first hinge frame (126-1inFIG.5), the second hinge frames126-2, the third hinge frames126-3, the first hinge parts (125-1inFIG.5), the second hinge parts125-2, and the plurality of stoppers140.

As described above, for example, one second hinge frame126-2may be coupled to either side of one first hinge frame126-1by means of the first hinge part125-1.

For example, one third hinge frame126-3may be coupled to the outer end of each of the second hinge frames126-2by means of the second hinge part125-2.

For example, the stoppers140may be respectively coupled to the outer ends of the third hinge frames126-3. For example, when the display device is viewed from the rear side, the stoppers140may be respectively disposed at the upper and lower sides of the outer ends of the third hinge frames126-3one by one to implement the horizontal curvature symmetry. That is, the stoppers140may be respectively disposed at the upper and lower sides of the outer ends of the third hinge frames126-3one by one to implement the curvature symmetry of the upper and lower sides of the display module110with respect to the third hinge frame126-3. However, the present disclosure is not limited thereto. The number and positions of the stopper may be adjusted depending on the magnitude of the force applied to unfold the display module110in the reverse direction (to the bending direction). For example, the pair of upper and lower stoppers140may have a horizontally symmetric structure. For example, the pair of stoppers140, which is disposed at the outer end of the third hinge frame126-3at the right side, and the pair of stoppers140, which is disposed outside the third hinge frame126-3at the left side, may have a vertically symmetric structure.

The stopper140according to the first aspect of the present disclosure may serve to restrict (block) the force applied to unfold the display module110in the reverse direction in the curved state (or curved surface state) of the display module110.

For example, the stopper140may be a thin plate and have a rectangular shape as a whole. However, the present disclosure is not limited thereto.

An elongated semicircular slit (or groove)143may be provided inside one side of the stopper140. A fixing portion141surrounded by the slit143may move upward or downward, like a flat spring.

As described above, in some aspects of the present disclosure, when the display module110changes to the flat state from the curved state in which the display module110is bent, the fixing portion141, which is surrounded by the slit143instead of the entire stopper140, moves upward or downward like the flat spring, which may reduce a force that pushes a polymer plate155. In addition, it is possible to reduce the force, which pushes the polymer plate155, by changing a position of an embossed portion142. As a result, it is possible to suppress noise and abrasion of constituent components, such as the polymer plate155, caused by repeated bending.

In this case, examples of the method of reducing the force applied to the embossed portion142includes a method of reducing the force applied to the embossed portion142in the flat state by forming the slit143around the embossed portion142, and a method of reducing the force applied to the embossed portion142by increasing a distance between the embossed portion142and the fixing portion141when energy for bending the flat spring is constant.

For example, the embossed portion142, which is a protruding structure, may be formed on a lower portion of the fixing portion141of the stopper140, and the embossed portion142may also move upward or downward in accordance with the upward or downward movement of the fixing portion141. In this case, the upward/downward direction means front and rear sides when viewed from the rear side in the state in which the display device stands upright.

For example, the embossed portion142may have a circular shape in a plan view. However, the present disclosure is not limited thereto.

The stopper140may be fastened to the display cover113by a fastening means146. For example, the stopper140may be fastened to a fixing means151by the fastening means146, and the fixing means151may be formed on the rear surface of the display cover113.

For example, the fastening means146may include a screw. In addition, for example, the fixing means151may include a nut or a press-in threaded insert nut (PEM nut).

The outer ends of the third hinge frames126-3may be bent upward and downward and constitute a pair of support portions153. For example, the support portion153has a rectangular shape as a whole. A slot may be formed in the support portion153and have a shape elongated in a longitudinal direction.

The polymer plate155, which has a shape (form) similar to that of the support portion153, may be disposed on the support portion153, and the stopper140may be disposed on the polymer plate155.

Individually, the polymer plate155is attached to the support portion153of the third hinge frame126-3, and the stopper140is fastened to the display cover113. Therefore, the third hinge frame126-3and the polymer plate155, which is attached to the support portion153of the third hinge frame126-3, may move leftward and rightward relative to the display cover113and the stopper140, which is fastened to the display cover113, in response to the flat state or the curved state of the display module110.

For example, the polymer plate155may have a rectangular shape as a whole. Similar to the support portion153, the polymer plate155may have a slot154formed in the polymer plate155and having a shape elongated in the longitudinal direction.

For example, the polymer plate155may include polyoxymethylene (POM). However, the present disclosure is not limited thereto.

For example, the slot154of the polymer plate155may correspond to the slot of the support portion153. The slot of the support portion153may be larger than the slot154of the polymer plate155.

For example, the slot154of the polymer plate155may include a plurality of circular first holes154-1. That is, the circular first holes154-1are formed at predetermined intervals in the longitudinal direction in the polymer plate155, such that the slot154having an elongated shape may be formed. In this case, the slot154may include the first holes154-1and a second hole154-2formed between the first holes154-1. The second hole154-2may have a smaller width than the first hole154-1.

For example, the first hole154-1may have a width or diameter to a degree to which the embossed portion142is inserted into the first hole154-1. In contrast, the second hole154-2may have a width smaller than a width of the embossed portion142.

Therefore, in case that the curved display mode is implemented by manipulating the display deformation drive part, the embossed portion142is positioned in the first hole154-1in a predetermined (or particular) curvature state, such that the embossed portion142may be inserted and fixed into the first hole154-1. In this case, it is possible to restrict the force applied to unfold the display module110in the reverse direction, such that the display module110may be kept in the predetermined (or particular) curvature state (seeFIGS.12A and12B).

In contrast, in case that the flat display mode is made or the display module110has a curvature between particular curvatures by manipulating the display deformation drive part, the embossed portion142is positioned in the second hole154-2, such that the embossed portion142may be positioned on the polymer plate155by being lifted upward without being inserted and fixed into the second hole154-2. In this case, the display module110may be kept in the flat state or slip toward the periphery to be in the curved state (seeFIGS.13A and13B).

As described above, the fixing portion141and the embossed portion142of the stopper140and the slot154of the polymer plate155, according to some aspects of the present disclosure, may constitute a primary curvature retention structure that restricts the force applied to unfold the display module110in the reverse direction.

The plurality of first holes154-1may be formed at predetermined (or particular) positions to implement a particular curvature of the display module110. The plurality of first holes154-1may serve to restrict the force applied to unfold the display module110in the reverse direction as the embossed portion142is inserted into (or caught by) the first hole154-1.

Meanwhile, the display device of the present disclosure may include a link structure configured to synchronize the pair of upper and lower stoppers140and inhibit the stoppers140from being distorted. That is, in case that the link structure is not provided in case that the stopper140and the display module110are fastened at a single point, the stoppers140may be distorted with respect to the fastening point (i.e., the fastening means146).

Therefore, for example, in the display device of the present disclosure, a link145may be attached to upper portions of the pair of upper and lower stoppers140in a direction in which the link145traverses the pair of stoppers140. For example, the link145may be attached to upper portions of the fixing portions141of the stoppers140that are opposite to the embossed portions142.

As described above, the embossed portion142, which is a protruding structure, may be formed on the lower portion of the fixing portion141of the stopper140, and the link145may be attached to the upper portion of the fixing portion141of the stopper140opposite to the embossed portion142, such that the embossed portion142and the link145may move upward and downward in accordance with the upward and downward movements of the fixing portion141. In this case, the upward/downward direction means front and rear sides when viewed from the rear side in the state in which the display device stands upright.

For example, the link145may have a bar shape. However, the present disclosure is not limited thereto.

The link145may serve to suppress the distortion of the stopper140by synchronizing the pair of upper and lower stoppers140when the stoppers140operate. If the stopper140is distorted, an operation defect and an insertion defect of protruding structures152occur.

Therefore, insertion holes145-1may be formed at two opposite ends of the link145of the present disclosure, and the protruding structures152may be inserted into the insertion holes145-1. In addition, the insertion hole145-1may also be formed at a center of the link145. However, the present disclosure is not limited thereto.

In this case, the plurality of protruding structures152may be formed on the rear surface of the display cover113and disposed at positions corresponding to the insertion holes145-1. The drawings illustrate an example in which three protruding structures152are disposed at each of the upper, lower, and central portions. However, the present disclosure is not limited thereto. The number of protruding structures152disposed to implement a particular curvature may vary.

For example, the protruding structure152may be disposed on the rear surface of the display cover113and have a height to a degree to which the protruding structure152penetrates the insertion hole145-1.

For example, the protruding structure152may be integrated with the display cover113. That is, the protruding structure152and the display cover113may be integrated, like a unified material, such that a component material may be simplified and unified.

For example, the plurality of protruding structures152may be disposed at intervals between the plurality of first holes154-1. However, the present disclosure is not limited thereto.

That is, the position of the protruding structure152may be determined depending on a free-stop position. In addition, the number of protruding structures152may be determined depending on a stopping reinforcement force.

As described above, the link145, together with the protruding structure152, may constitute a secondary curvature retention structure for minimizing bending rigidity of the embossed portion142.

Therefore, in case that the curved display mode is implemented by manipulating the display deformation drive part, a slip occurs between the display cover113and the third hinge frame126-3, and the fixing portion141of the stopper140moves upward or downward. In addition, the link145attached to the upper portion of the fixing portion141also moves upward or downward. In this case, as the link145moves upward or downward, the protruding structure152may be inserted and fixed into the insertion hole145-1of the link145. Therefore, in this case, it is possible to restrict the force applied to unfold the display module110in the reverse direction, such that the display module110may be kept in the predetermined (or particular) curvature state (seeFIGS.12A and12B).

In this case, in case that the secondary curvature retention structure is applied, the embossed portion142may perform the function of moving the secondary curvature retention structure upward or downward rather than the stopper function.

In contrast, in case that the flat display mode is made or the display module110has a curvature between particular curvatures by manipulating the display deformation drive part, the embossed portion142is positioned in the second hole154-2, such that the embossed portion142may be positioned on the polymer plate155by being lifted upward without being inserted and fixed into the second hole154-2. In this case, the link145attached to the upper portion of the fixing portion141is also lifted upward and positioned between the protruding structures152. Therefore, the display module110may be kept in the flat state or slip toward the periphery to be in the curved state (seeFIGS.13A and13B).

The drawings illustrate an example in which the single link145constitutes the secondary curvature retention structure. However, the present disclosure is not limited thereto. Two or more links145may be disposed. In this case, the protruding structures152disposed at two or more points may be inserted into two or more links145.

FIGS.14A and14Bare views illustrating simulation results showing examples of equivalent stress of a comparative example according to some aspects of the present disclosure.

FIGS.15A and15Bare views illustrating simulation results showing examples of equivalent stress of a comparative example according to some aspects of the present disclosure.

In this case, a boundary condition of the simulation is a case in which the embossed portion is moved upward by about 5.0 mm.

For reference, equivalent stress refers to a concept used to evaluate an overall stress state of a material or structure. The equivalent stress may be represented by a single scalar value made by combining multiple stresses in a complex stress situation that occurs when a three-dimensional object is subjected to various loads.

With reference toFIGS.14A and14B, it may be seen that the maximum stress is about 19, 955 MP in the case of the comparative example, and the maximum stress is measured at the periphery of the embossed portion and the periphery of the fixing portion.

In contrast, with reference toFIGS.15A and15B, it may be seen that in the case of the this non-limiting comparative example, the maximum stress is about 4, 369.3 MP at the periphery of the embossed portion and about 2, 570.3 MP at the periphery of the fixing portion, and the maximum stress is significantly decreased in comparison with the maximum stress in the comparative example.

Meanwhile, in the present disclosure, the stoppers may not only be disposed at the outer ends of the third hinge frame but also be additionally disposed on the second hinge part. This configuration will be described with reference toFIG.16.

FIG.16is a rear view illustrating a display device according to some aspects of the present disclosure.

The example inFIG.16is substantially identical in configuration to aspects of the present disclosure described with reference toFIGS.3to13A and13B, except that a second stopper240bis also additionally on a second hinge part126-2. Therefore, the same reference numerals are assigned to the same components, and a description thereof will be omitted.

FIG.16is a view illustrating a rear surface of a display device200according to the second aspect of the present disclosure that does not include the stand115, the hinge cover121, and the stand fastening part124. For convenience of description,FIG.16illustrates a state in which the left side of the hinge unit is excluded.

With reference toFIG.16, the display device200may include the display module110, the stand115, and the display deformation drive part120.

The display deformation drive part may include the hinge unit configured to deform the display module110to the flat state or the curved state, and the hinge cover121configured to cover the hinge unit. A detailed description of the display module110, the hinge unit122, and the hinge cover121may be the same as that described above with reference toFIGS.3to13A and13B.

As described above, for example, the hinge unit may include the first hinge frame126-1, the second hinge frames126-2, the third hinge frames126-3, the first hinge parts125-1, the second hinge parts125-2, and a plurality of stoppers240aand240b.

For example, one second hinge frame126-2may be coupled to either side of one first hinge frame126-1by means of the first hinge part125-1as described above.

For example, one third hinge frame126-3may be coupled to the outer end of each of the second hinge frames126-2by means of the second hinge part125-2as described above.

For example, the pair of first stoppers240amay be respectively coupled to the outer ends of the third hinge frames126-3. That is, for example, when the display device200is viewed from the rear side, the first stoppers240amay be respectively disposed at the upper and lower sides of the outer ends of the third hinge frames126-3one by one. However, the present disclosure is not limited thereto. The number and positions of the stoppers240amay be adjusted by a magnitude of a force applied to unfold the display module110in the reverse direction (to the bending direction).

In some examples, a pair of second stoppers240bmay be respectively coupled to the second hinge frames126-2. For example, when the display device200is viewed from the rear side, the second stoppers240bmay be respectively disposed at the upper and lower sides of the second hinge frames126-2one by one. However, the present disclosure is not limited thereto. The number and positions of the second stoppers240bmay be adjusted by a magnitude of a force applied to the display module110to unfold the display module110in the reverse direction.

For example, the first stopper240aand the second stopper240bmay be disposed at the same horizontal position.

Detailed structures of the first stopper240aand the second stopper240bmay be the same as described above with reference toFIGS.3to13A and13B.

As described above, the hinge unit may include the single first hinge frame126-1, the two second hinge frames126-2, the two third hinge frames126-3, the two first hinge parts125-1, the two second hinge parts125-2, the two pairs of first stoppers240a, and the two pairs of second stoppers240b. However, the present disclosure is not limited thereto.

Meanwhile, in the present disclosure, a stopper structure may be formed by additionally extending an end of the third hinge frame. This configuration will be described in detail with reference to the drawings.

FIG.17is a rear view illustrating a display device according to some aspects of the present disclosure.

FIGS.18A and18Bare rear views illustrating a part of a rear surface of the display device according to some aspects of the present disclosure.

FIGS.19A and19Bare perspective views illustrating a part of the rear surface of the display device according to some aspects of the present disclosure.

FIG.17is a view illustrating a rear surface of a display device300that does not include the stand115, the hinge cover121, and the stand fastening part124. For convenience of description,FIG.17illustrates a state in which the left side of the hinge unit is excluded.

FIG.18Aillustrates an example of a part of the rear surface of the display device in a state in which the hinge unit is removed.

FIGS.18B and19Aillustrate an example of a part of the rear surface of the display device including the hinge unit122.FIG.19Billustrates enlarged part E inFIG.19A.

Example aspect described with reference toFIGS.17,18A,18B,19A, and19Bis substantially identical in configuration to aspects described with reference toFIGS.3to13A and13B, except that a stopper340is formed by extending an end of a third hinge frame326-3. Therefore, the same reference numerals are assigned to the same components, and a description thereof will be omitted.

With reference toFIGS.17,18A,18B,19A, and19B, display device300according to aspects of the present disclosure may include the display module110, the stand115, and the display deformation drive part120.

For example, the hinge unit may include the first hinge frame126-1, the second hinge frames126-2, the third hinge frames326-3, the first hinge parts125-1, the second hinge parts125-2, and the stoppers340.

As described above, for example, one second hinge frame126-2may be coupled to either side of one first hinge frame126-1by means of the first hinge part125-1.

For example, one third hinge frame326-3may be coupled to the outer end of each of the second hinge frames126-2by means of the second hinge part125-2.

For example, the stopper340may be formed by extending the outer end of each of the third hinge frames326-3in a length direction. As described above, the stopper340may be integrated with the third hinge frame326-3. That is, the stopper340and the third hinge frame326-3may be integrated, like a unified material, such that a component material may be simplified and unified.

For example, a lower side of the outer end of the third hinge frame326-3may extend in the length direction and be bent twice, such that the bent end may define the stopper340.

In some aspects, the end of the third hinge frame326-3constitutes the stopper340, which may inhibit the stoppers from being disposed to be horizontally asymmetric. Therefore, it is possible to suppress a problem with a horizontally asymmetric curvature of the display module110.

An elongated semicircular slit (or groove)343may be provided inside one side of the stopper340. A fixing portion341surrounded by the slit343may move upward or downward, like a flat spring. In this case, the slit343has a semicircular shape opened at an outer side thereof. However, the present disclosure is not limited thereto.

In addition, for example, an embossed portion, which is a protruding structure, may be formed on a lower portion of the fixing portion341of the stopper340, and the embossed portion may also move upward or downward in accordance with the upward or downward movement of the fixing portion341.

For example, a plurality of circular holes354may be provided in the rear surface of the display cover113and disposed at predetermined (or particular) intervals.

For example, the hole354may have a width or diameter to a degree to which the embossed portion is inserted into the hole354.

Therefore, in case that the curved display mode is implemented by manipulating the display deformation drive part, the embossed portion is positioned in the hole354in a particular curvature state, such that the embossed portion may be inserted and fixed into the hole354. In this case, it is possible to restrict the force applied to unfold the display module110in the reverse direction, such that the display module110may be kept in the particular curvature state.

In contrast, in case that the flat display mode is made or the display module110has a curvature between particular curvatures by manipulating the display deformation drive part, the embossed portion is positioned between the holes354, such that the embossed portion is lifted upward and positioned on the rear surface of the display cover113without being inserted and fixed into the hole354. In this case, the display module110may be kept in the flat state or slip toward the periphery to be in the curved state.

As described above, the plurality of holes354and the fixing portion341and the embossed portion of the stopper340may constitute a primary curvature retention structure that restricts the force applied to unfold the display module110in the reverse direction.

The plurality of holes354may be formed at predetermined (or particular) positions to implement a particular curvature of the display module110.

For example, in the display device300, a link345may be attached to an upper portion of the stopper340in a direction in which the link345traverses the stopper340. For example, the link345may be attached to upper portion of the fixing portion341of the stopper340opposite to the embossed portion142.

Therefore, the embossed portion, which is a protruding structure, may be formed on the lower portion of the fixing portion341of the stopper340, and the link345may be attached to the upper portion of the fixing portion341of the stopper340opposite to the embossed portion, such that the embossed portion and the link345may move upward and downward in accordance with the upward and downward movements of the fixing portion341.

For example, the link345may have a bar shape. However, the present disclosure is not limited thereto.

In addition, insertion holes345-1may be formed at two opposite ends of the link345of the present disclosure, and protruding structures352may be inserted into the insertion holes345-1.

In this case, the plurality of protruding structures352may be formed on the rear surface of the display cover113and disposed at positions corresponding to the insertion holes345-1. The drawings illustrate an example in which three protruding structures352are disposed at each of the upper and lower portions. However, the present disclosure is not limited thereto. The number of protruding structures352disposed to implement a or particular curvature may vary.

For example, the protruding structure352may be disposed on the rear surface of the display cover113and have a height to a degree to which the protruding structure352penetrates the insertion hole345-1.

For example, the plurality of protruding structures352may be disposed at intervals between the plurality of holes354. However, the present disclosure is not limited thereto.

As described above, the link345, together with the protruding structure352, may constitute a secondary curvature retention structure for minimizing bending rigidity of the embossed portion.