Patent Description:
A display device is a device having a function of receiving, processing, and displaying a video that a user may watch. For example, the display device receives a broadcast selected by the user from broadcast signals transmitted from a broadcasting station, separates a video signal from the received signals, and displays the separated video signal on a display.

In recent years, because of a development of a broadcasting technology and a network technology, functions of the display device have also been considerably diversified, and a performance of the device has been improved accordingly. That is, the display device has been developed to provide not only broadcast contents but also various other contents to the user. For example, the display device may provide game play, music listening, internet shopping, user customized information, and the like using various applications as well as programs received from the broadcasting station. In order to perform such extended functions, the display device may be basically connected to other devices or networks using various communication protocols, and may provide the user with an ubiquitous computing environment. In other words, the display device has evolved into a smart device that enables connectivity to a network and continuous computing.

Meanwhile, recently, a flexible display having elasticity sufficient to enable major deformation thereof has been developed. The size of the mobile terminal may be varied by using the deformable property of the flexible display. In a mobile terminal having a structure that is variable in size, changes in the structure of the mobile terminal must be made reliably. However, in such a mobile terminal, a supporting structure or others for a variable display unit may be problematic. <CIT> relates to a mobile terminal including a housing and a flexible screen, a control system, and a control method. <CIT> relates to an electronic device with a flexible display having an expandable display area.

An object of the present disclosure is to provide a mobile terminal having a structure that assists sliding movement.

The mobile terminal may further include a driving unit configured to move the second frame in the first direction or in a second direction, which is opposite the first direction, with respect to the first frame.

The flexible rack gear may include a plurality of grooves extending in a third direction, which is perpendicular to the first direction, and arranged side by side in the first direction.

The support frame may include a plurality of rigid bars extending in a third direction, which is perpendicular to the first direction, and arranged side by side in the first direction, and a flexible portion connecting the rigid bars.

The flexible display unit may include a variable portion positioned on the front surface of the body or on the rear surface of the body depending on the position of the second frame, and the support frame may be located on another surface of the variable portion of the flexible display unit.

The pinion gear may be formed on the outer circumferential surface of the roller.

The roller may include a first portion on which the pinion gear is formed, a second portion in the shape of a pipe having a hollow formed therein, and a first fastening portion, which is formed in the hollow, placed at an end of the first portion, and exposed outside. The auxiliary driving unit may include an elastic part having one end thereof coupled to the first fastening portion and having another end thereof coupled to a second fastening portion provided on the second frame.

The second fastening portion may have one side thereof coupled to the other end of the elastic part and located in the hollow in the second portion, and another side thereof fastened to the second frame using a screw.

The elastic part may include a coil spring.

The roller may further include an opening, which is formed in an outer circumferential surface of the second portion and exposes the first fastening portion.

The second portion may be provided on each of opposite sides of the first portion.

A mobile terminal of the present disclosure may stably move a flexible display unit according to the movement of a second frame.

In addition, due to the tensile force provided to the flexible display unit, the flexible display unit may remain flat without lifting, and may remain in close contact with the body of the mobile terminal.

Description will now be given in detail according to exemplary embodiments disclosed herein, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components may be provided with the same reference numbers, and description thereof will not be repeated. In general, a suffix such as "module" and "unit" may be used to refer to elements or components. Use of such a suffix herein is merely intended to facilitate description of the specification, and the suffix itself is not intended to give any special meaning or function. In the present disclosure, that which is well-known to one of ordinary skill in the relevant art has generally been omitted for the sake of brevity. The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings.

It will be understood that when an element is referred to as being "connected with" another element, the element can be directly connected with the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly connected with" another element, there are no intervening elements present.

The mobile terminal <NUM> is shown having components such as a wireless communication unit <NUM>, an input unit <NUM>, a sensing unit <NUM>, an output unit <NUM>, an interface unit <NUM>, a memory <NUM>, a controller <NUM>, and a power supply unit <NUM>. It is understood that implementing all of the illustrated components in FIG. 1A is not a requirement, and that greater or fewer components may alternatively be implemented than the components listed above.

The mobile communication module <NUM> can transmit and/or receive wireless signals to and from one or more network entities. Typical examples of a network entity include a base station, an external mobile terminal, a server, and the like. Such network entities form part of a mobile communication network, which is constructed according to technical standards or communication methods for mobile communications (for example, Global System for Mobile Communication (GSM), Code Division Multi Access (CDMA), CDMA2000(Code Division Multi Access <NUM>), EV-DO(Enhanced Voice-Data Optimized or Enhanced Voice-Data Only), Wideband CDMA (WCDMA), High Speed Downlink Packet access (HSDPA), HSUPA(High Speed Uplink Packet Access), Long Term Evolution (LTE) , LTE-A(Long Term Evolution-Advanced), and the like).

Data (for example, audio, video, image, and the like) is obtained by the input unit <NUM> and may be analyzed and processed as a user's control command.

Such cameras <NUM> may process image frames of still pictures or video obtained by image sensors in a video or image capture mode. The processed image frames can be displayed on the display unit <NUM> or stored in memory <NUM>. In some cases, the cameras <NUM> may be arranged in a matrix configuration to permit a plurality of images having various angles or focal points to be input to the mobile terminal <NUM>. As another example, the cameras <NUM> may be located in a stereoscopic arrangement to acquire left and right images for implementing a stereoscopic image.

The sensing unit <NUM> is typically implemented using one or more sensors configured to sense internal information of the mobile terminal, the surrounding environment of the mobile terminal, user information, and the like. For example,, the sensing unit <NUM> may alternatively or additionally include other types of sensors or devices, such as a proximity sensor <NUM> and an illumination sensor <NUM>, a touch sensor, an acceleration sensor, a magnetic sensor, a G-sensor, a gyroscope sensor, a motion sensor, an RGB sensor, an infrared (IR) sensor, a finger scan sensor, a ultrasonic sensor, an optical sensor (for example, camera <NUM>), a microphone <NUM>, a battery gauge, an environment sensor (for example, a barometer, a hygrometer, a thermometer, a radiation detection sensor, a thermal sensor, and a gas sensor, among others), and a chemical sensor (for example, an electronic nose, a health care sensor, a biometric sensor, and the like), to name a few. The mobile terminal <NUM> may be configured to utilize information obtained from sensing unit <NUM>, and in particular, information obtained from one or more sensors of the sensing unit <NUM>, and combinations thereof.

The controller <NUM> typically functions to control overall operation of the mobile terminal <NUM>, in addition to the operations associated with the application programs. The controller <NUM> may provide or process information or functions appropriate for a user by processing signals, data, information and the like, which are input or output, or activating application programs stored in the memory <NUM>.

To drive the application programs stored in the memory <NUM>, the controller <NUM> may be implemented to control a predetermined number of the components mentioned above in reference with FIG. Moreover, the controller <NUM> may be implemented to combinedly operate two or more of the components provided in the mobile terminal <NUM> to drive the application programs.

<FIG> is an exploded perspective view illustrating a mobile terminal according to the present disclosure. <FIG> is a perspective view illustrating first and second states of a mobile terminal viewed in one lateral side. <FIG> is a rear view illustrating first and second states of a mobile terminal. <FIG> is a sectional view illustrating first and second states of a mobile terminal, obtained along the cutting lines A-A and B-B of <FIG>, respectively. In the above drawings, <FIG>, <FIG> and <FIG> illustrate a first state of a mobile terminal and <FIG>, <FIG> and <FIG> illustrates a second state of the mobile terminal.

As illustrated in the drawings, a mobile terminal <NUM> of a first state is contracted (or retracted) and has a size smaller than that of the mobile terminal <NUM> of a second state. Moreover, a size of a display <NUM> located on a front surface of the mobile terminal <NUM> becomes smaller than that in a second state. On the other hand, the mobile terminal <NUM> of the first state is extended in a first direction D1 so as to switch to the second state. In the second state, a size of the mobile terminal <NUM> and a size of the display <NUM> located on the front surface become greater than those of the first state. In the following description, a direction in which the mobile terminal <NUM> and the display <NUM> thereof are extended (or enlarged) is referred to as a first direction D1, a direction in which the mobile terminal <NUM> and the display <NUM> thereof are contracted (or retracted) or reduced is referred to as a second direction D2, and a direction vertical to the first and second directions D1 and D2 is referred to as a third direction.

The mobile terminal <NUM> of the present disclosure may switch from the first state in which the display <NUM> is located on the front surface like a bar-type mobile terminal like <FIG> to the second state by extending the screen like <FIG>. In the second state, a size of the display <NUM> located on the front surface is enlarged and a size of the display <NUM> located on a rear surface is reduced like <FIG>. Namely, the display <NUM> used to be located on the rear surface of the mobile terminal <NUM> in the first state is moved to the front surface of the mobile terminal <NUM> in the second state.

Thus, in order for a position of the display to be variable, the display may employ a flexible display unit <NUM>. A flexible display means a display that is light-weighted, easilyunbreakable and heavy-duty display fabricated on a thin and flexible substrate capable of curving, bending, folding, twisting and rolling-up like a paper by maintaining the properties of the existing flat panel display.

Moreover, an electronic paper employs a display technology provided with the features of the normal ink and may differ from the existing flat panel display in using reflective light. The electronic paper may change information by electrophoresis using twist balls or capsules.

In a state that the flexible display unit <NUM> is not deformed (e.g., a state having an infinite curvature radius: hereinafter a basic state), a display region of the flexible display unit <NUM> becomes a plane. In a state deformed from the basic state by an external force (e.g., a state having a finite curvature radius: hereinafter a deformed state), the display region may become a curved surface. As illustrated in the drawing, information displayed in the deformed state may become visual information outputted to the curved surface. Such visual information is implemented in a manner that light emittance of subpixels deployed in a matrix form is controlled independently. The subpixel means a minimum unit for implementing a single color.

The flexible display unit <NUM> may lie not in a flat state but in a curved state (e.g., a top-bottom or right-left curved state) from the basic state. In this case, if an external force is applied to the flexible display unit <NUM>, the flexible display unit <NUM> may be deformed into a flat state (or a less-curved state) or a more-curved state.

Meanwhile, the flexible display unit <NUM> may implement a flexible touchscreen by being combined with a touch sensor. If a touch is applied to the flexible touchscreen, the controller <NUM> (see <FIG>) may perform a control in response to such a touch input. The flexible touchscreen may be configured to sense a touch input in the deformed state as well as in the basic state.

The touch sensor senses a touch (or a touch input) applied to the touchscreen using at least one of various touch types such as a resistance layer type, an electrostatic capacitance type, an infrared type, an ultrasonic type, etc..

For example, a touch sensor may be configured to convert a pressure applied to a specific portion of a touchscreen or a variation of electrostatic capacitance generated from the specific portion into an electric input signal. A touch sensor may be configured to detect a position or size of the touch sensor touched by a touch target applying a touch to a touchscreen, a pressure of the touch, an electrostatic capacitance of the touch, etc..

Meanwhile, a deformation sensing means for sensing deformation of the flexible display unit <NUM> may be provided to the mobile terminal <NUM>. Such a deformation sensing means may be included in the sensing unit <NUM> (see <FIG>).

The deformation sensing means is provided to the flexible display unit <NUM> or the case (or housing) (i.e., first to third frame <NUM> to <NUM> described later), thereby sensing information related to deformation of the flexible display unit <NUM>. Here, the information related to the deformation includes a deformed direction of the flexible display unit <NUM>, a deformed extent, a deformed position, a deformed time, a restored acceleration of the deformed flexible display unit <NUM>, etc., and may further various kinds of information sensible as the flexible display unit <NUM> is curved.

Based on the information related to the deformation of the flexible display unit <NUM> and sensed by the deformation sensing means, the controller <NUM> may change information displayed on the flexible display unit <NUM> or generate a control signal for controlling a function of the mobile terminal <NUM>.

The size changes of the display unit <NUM> on the front and rear surfaces of the mobile terminal according to the state switching (first or second state) of the flexible display unit <NUM>, i.e., the size change of the mobile terminal <NUM> may be performed manually by a force applied by a user, which is non-limited by the manual way. For example, when the mobile terminal <NUM> or the flexible display unit <NUM> is in the first state, it may be deformed into the second state by a command of a user or application without an external force applied by the user. Thus, in order for the flexible display unit <NUM> to be automatically deformed without such an external force, the mobile terminal <NUM> may include a driving unit <NUM> described later.

The flexible display unit <NUM> of the present disclosure is rolled round a predetermined one of both side parts of the mobile terminal <NUM>, thereby being folded at <NUM>°. Hence, one portion of the display unit <NUM> is disposed on the front surface of the mobile terminal <NUM> with reference to such a side part, while the rest is disposed on the rear surface of the mobile terminal <NUM>. Some portion of the display unit <NUM> located on the front surface of the mobile terminal <NUM> may be fixed to the front surface not to move, while the rest of the display unit <NUM> located on the rear surface of the mobile terminal <NUM> may be provided to be movable on the rear surface.

The display unit <NUM> may be rolled or unrolled round the side part, whereby a size of the region disposed on the front surface of the mobile terminal <NUM> may be adjusted by moving a part of the display unit <NUM> disposed on the rear surface of the mobile terminal <NUM>. Since a size of the flexible display unit <NUM> is determined and the flexible display unit <NUM> includes a single continuous body, if a size of the flexible display unit <NUM> located on the front surface of the mobile terminal <NUM> is increased, a size of the flexible display unit <NUM> located on the rear surface of the mobile terminal <NUM> is decreased. The above-configured display unit <NUM> may be rolled within the second frame <NUM> relatively movable to the first frame <NUM>, which will be described later, and more specifically, around a predetermined side part of the second frame <NUM>, and withdrawn (or pulled out) from or inserted (or pushed) into the second frame <NUM> by being rolled around the second frame <NUM> along a moving direction of the second frame <NUM> to adjust the size of the display unit <NUM> on the front surface of the mobile terminal <NUM>. Such an operation will be described in detail together with other related components of the mobile terminal <NUM>.

Typically, an antenna is disposed in the case or the housing of the mobile terminal <NUM>, but a portion where the antenna is installed in the case or the housing may be limited because of the flexible display unit <NUM> that covers not only the front face of the mobile terminal <NUM> but also the rear face thereof. For this reason, the antenna may be implemented on the flexible display unit <NUM>. An antenna on display (AOD) is an antenna in which a transparent film is formed by stacking an electrode layer and a dielectric layer that have patterns engraved thereon, respectively. The antenna on display may be implemented thinner than an antenna implemented using a laser direct structuring (LDS) technology using a conventional copper nickel plating scheme, so that the antenna on display may not be exposed to the outside without affecting a thickness. In addition, the antenna on display may transmit and receive a signal directly to or from the display unit <NUM>. Accordingly, the antenna on display may be used in the mobile terminal <NUM> in which the display unit <NUM> is located on the both faces of the mobile terminal <NUM> as in the present disclosure.

With reference to <FIG>, a detailed configuration of the mobile terminal <NUM> of the present disclosure will be described in detail below. A following description will be achieved basically with reference to <FIG> illustrating an overall configuration. <FIG> are referred to to explain detailed features of corresponding components in the first and second states of the mobile terminal <NUM>.

The mobile terminal <NUM> of the present disclosure includes a main frame in which components are mounted, and the main frame of the present disclosure may vary in size in the first direction as shown in <FIG>. One or more frames move relative to each other, and sizes thereof may vary in the first direction. Electronic components are mounted in the main frame, and the flexible display unit <NUM> is located out of the main frame.

Since the mobile terminal <NUM> of the present disclosure includes the flexible display unit, the flexible display unit <NUM> may be combined in a form surrounding a front face and a rear face of the main frame. The main frame may include first to third frames <NUM> to <NUM>. The main frame may include the first frame <NUM>, the second frame <NUM> moving in the first direction with respect to the first frame <NUM>, and the third frame <NUM> moving in the first direction with respect to the second frame <NUM>. The first frame <NUM> and the second frame <NUM> include front portions, a rear portions, and side portions, respectively, and are coupled to each other. Thus, the mobile terminal <NUM> may have a hexahedral outer shape by such coupled first and second frames <NUM> and <NUM>. In consideration of an illustrated configuration of the first to third frames <NUM> to <NUM>, movements of the second and third frames <NUM> and <NUM> may be a slide movement.

First of all, the first frame <NUM> corresponds to a main body of the mobile terminal <NUM> and may form a space inside to receive various parts therein. And, the first frame <NUM> may receive the second frame <NUM>, which is movably coupled to the first frame <NUM>, within such a space. Particularly, as illustrated in <FIG> and <FIG>, the first frame <NUM> may include a first front part <NUM> disposed on the front surface of the mobile terminal <NUM> and first and second rear parts <NUM> and <NUM> disposed on the rear surface of the mobile terminal <NUM>.

Each of the first front part <NUM>, the first rear part <NUM> and the second rear part <NUM> may include an approximately flat plate-type member. The first rear part <NUM> and the second rear part <NUM> may include separate members coupled together or a single member illustrated in the drawing. In order to form a predetermined space, the first font part <NUM> and the first/second rear part <NUM>/<NUM> may be spaced apart from each other in a predetermined gap and connected to each other by a lateral part <NUM>. As parts of the mobile terminal <NUM>, the controller <NUM> and the power supply unit <NUM> may be received in the space within the first frame <NUM>. For example, the controller <NUM> may include a circuit board including a processor and electronic circuit for controlling operations of the mobile terminal <NUM> and the power supply unit <NUM> may include a battery and related parts. Moreover, the second frame <NUM> and the driving unit <NUM> described alter may be received in the first frame <NUM> as well.

As described above, the display unit <NUM> has the continuous body, and thus, may be disposed on both the front face and the rear face of the mobile terminal <NUM> while being rolled in the mobile terminal <NUM>. The display unit <NUM> may include the front face positioned at the front face of the mobile terminal <NUM>, the rear face positioned at the rear face of the mobile terminal <NUM>, and the side face positioned between the front face and the rear face thereof and surrounding the side face of the mobile terminal. The front face and the rear face of the display unit <NUM> are flat, and the side face of the display unit <NUM> may form a curved face. When the flexible display unit <NUM> may be damaged when being bent. Thus, the flexible display unit <NUM> may be formed to be bent with a predetermined curvature.

The display unit <NUM> may be divided into a fixed portion and a variable portion. The fixed portion means a portion fixed to the frame. Because of being fixed to the frame, the fixed portion maintains a constant shape without changing a bending degree. On the other hand, the variable portion means a portion in which a bending angle or a position of the bent portion changes. The variable portion in which the position or bending angle of the bent portion changes requires a structure for supporting a rear face of the variable portion in response to the change.

A first region of the display unit <NUM> may be coupled to the first front portion <NUM> corresponding to the front face of the mobile terminal <NUM>.

On the other hand, as well illustrated in <FIG>, for the installation of various physical input units <NUM> and sensor units <NUM> for manipulations of the mobile terminal <NUM>, the display unit <NUM> may be disposed on the second rear part <NUM> only. Since the first rear part <NUM> is always exposed externally, the input unit <NUM> such as various buttons, switches, the camera <NUM> and a flash and the sensor unit <NUM> such as the proximity sensor <NUM> may be disposed on the first rear part <NUM>. A typical bar-type terminal includes a display unit provided to a front surface of the terminal only. Hence, a camera is disposed on a rear surface of the terminal in order to capture an image by viewing a thing located at the opposite side of a user through a display unit. In order for the user to capture himself by viewing himself through the display unit, an additional camera needs to be provided to the front surface of the terminal.

Yet, according to the mobile terminal <NUM> of the present disclosure, the display unit <NUM> is located on both of the front and rear surfaces thereof. Therefore, when a user takes a selfie, the display unit located on the same side of the camera <NUM>, i.e., a portion of the display unit <NUM> located on the rear surface of the mobile terminal <NUM> in the drawing may be used. When a thing at the opposite side of the user is captured, the display unit located on the opposite side of the camera <NUM>, i.e., a portion of the display unit <NUM> on the front surface of the mobile terminal <NUM> in the drawing may be used. For that reason, the mobile terminal <NUM> may capture a thing located at the opposite side of a user or a selfie using the single camera <NUM>. The camera may include a plurality of cameras of different view angles such as a wide angle, a super wide angle, a telescope, etc. A proximity sensor, an audio output module and the like may be located on the first rear part <NUM> as well as the camera, and an antenna <NUM> may be installed thereon.

The lateral part <NUM> may be elongated along edges of the first front part <NUM> and the first/second rear part <NUM>/<NUM> to enclose a circumference of the first frame <NUM> and form an exterior of the mobile terminal <NUM>. Yet, as mentioned above, since the second frame <NUM> is received in the first frame <NUM> and movably coupled thereto, a portion of the first frame <NUM> needs to be open to allow the relative movement of the second frame <NUM> to the first frame <NUM>. As well illustrated in <FIG>, for example, since the second frame <NUM> is movably coupled to one of both side parts of the first frame <NUM>, the lateral part <NUM> is not formed at such a side part, thereby opening it. Hence, the first frame <NUM> may include a first side part 101a substantially closed and a second side part 101b disposed to oppose the first side part 101a so as to be open. Since the lateral part <NUM> is exposed from the mobile terminal <NUM>, the interface unit <NUM> for connecting to a power port or an earphone jack or the user input unit <NUM> such as a volume button and the like may be disposed thereon. In case of containing metal substance, the lateral part <NUM> may play a role as an antenna.

The second rear portion <NUM> of the first frame <NUM> may be covered by the display unit, but may be disposed on the front face of the display unit using a transparent material.

Referring to <FIG>, the second frame <NUM> may include a second front part <NUM> disposed on the front surface of the mobile terminal <NUM> and a third rear part <NUM> disposed on the rear surface of the mobile terminal <NUM>. Like the first front part <NUM>, the first rear part <NUM> and the second rear part <NUM> of the first frame <NUM>, each of the second front part <NUM> and the third rear part <NUM> may be formed of an approximately flat plate-type member. Moreover, the second frame <NUM> may receive various parts therein and should not interfere with the parts received in the first frame <NUM> while moving. Hence, the second front part <NUM> and the third rear part <NUM> may be coupled together in a manner of being spaced apart from each other and have a shape not interfering with the parts within the first frame <NUM>.

Moreover, the display unit <NUM> may be folded at <NUM>° while being rolled up within the second frame <NUM> so as to be disposed on both of the front and rear surfaces of the mobile terminal <NUM>. For such arrangement of the display <NUM>, the second frame <NUM> may include a roller <NUM> rotatably disposed therein. The roller <NUM> may be disposed at a random position within the second frame <NUM>. Yet, the display <NUM> should be spread flat on the front and rear surfaces of the mobile terminal <NUM> to provide a user with a screen of a good quality. For such a spread, an appropriate tension should be provided to the display <NUM>. In order to provide the proper tension, the roller <NUM> may be disposed at a first directional end of the second frame <NUM>. The roller <NUM> may extend in the third direction, and may be rotatably coupled to the second frame <NUM>.

The display unit <NUM> may be rolled around the roller <NUM> by being gradually curved with a predetermined curvature. Moreover, the roller <NUM> may be installed to freely rotate on the second frame <NUM> by contacting with an inner surface of the display unit <NUM>. Therefore, the roller <NUM> is substantially capable of moving the display unit <NUM> in a direction vertical to a lateral direction, i.e., a length direction of the mobile terminal <NUM>. As described later, when the second frame <NUM> is slid, the display unit <NUM> is moved by the tension applied by the second frame <NUM> to the front or rear surface of the mobile terminal <NUM> relatively to the second frame <NUM> in a different direction (i.e., the first direction D1 or the second direction D2). In doing so, such a movement may be guided by the roller <NUM> that is rotating.

In addition, the roller <NUM> is disposed on a first side portion 102a of the second frame <NUM>, and the first side portion 102a actually corresponds to an outermost side portion of the mobile terminal <NUM>. When the first side portion 102a of the second frame <NUM> is exposed, the display unit <NUM> rolled on the roller <NUM> may be damaged. Accordingly, the second frame <NUM> may include a side frame <NUM> disposed on the first side portion 102a.

The side frame <NUM> extends in the longitudinal direction of the second frame <NUM> to cover the first side portion 102a, thereby protecting the roller <NUM> and the display unit <NUM> rolled thereon. That is, the side frame <NUM> covers the side face of the display unit <NUM>, and the side face thereof is located in the third region. The first to third regions are at specified positions on the flexible display unit and do not change in size or position, but the sizes of the front face and the rear face, and the position of the side face are determined based on the state of the main frame.

The first region and the second region correspond to the fixed portion described above, and the third region corresponds to the variable portion described above.

The third region may vary in position depending on the state of the mobile terminal. Because the side face is rolled by the roller, the side face is bent with the predetermined curvature, and an inner face of the side frame may include a curved face corresponding to the curvature of the side face.

Because of the side frame <NUM>, the second frame <NUM> may have the substantially closed first side portion 102a, and the side frame <NUM> may substantially form the outer shape of the mobile terminal <NUM> together with the side face <NUM> of the first frame <NUM>. In addition, the second frame <NUM> may include a second side portion 102b that is disposed opposite the first side portion 102a to minimize interference with the components within the first frame <NUM> during the movement, and is opened.

Such a second frame <NUM> is movably coupled to the first frame <NUM>, and thus may slide in the predetermined first or second direction D1 or D2 relative to the first frame <NUM>. More specifically, the second frame <NUM> may be movably coupled to the first frame <NUM> through the side portion of the first frame <NUM>, more precisely, through the opened second side portion 101b, as shown. More specifically, the second side portion 102b of the second frame is disposed relatively adjacent to the first side portion 101a of the first frame <NUM> which is closed. Accordingly, the first side portion 102a of the second frame may be disposed to be opposite to the first side portion 101a. Accordingly, the second side portion 102b is inserted into the first frame <NUM> through the side portion of the first frame, that is, the second side portion 101b thereof. The first side portion 102a is not inserted into the first frame <NUM> but is always located outside the first frame <NUM>, thereby forming the outer shape of the mobile terminal <NUM> as described above. However, when necessary, such first side portion 102b of the second frame <NUM> may also be inserted into the first frame <NUM>.

Because of such positional relationship, the second frame <NUM> may extend from or contract to the first frame <NUM> in a direction perpendicular to the longitudinal direction of the mobile terminal <NUM> or the first frame <NUM>. That is, the first and second directions D1 and D2 may basically be directions perpendicular to the longitudinal direction of the mobile terminal <NUM> or the first frame <NUM>. Further, the first and second directions D1 and D2 may also be described as the lateral direction or the horizontal direction of the mobile terminal <NUM> or the first frame <NUM>. In addition, during the movement in the first direction D1, the second frame <NUM> extends from the first frame <NUM>. Accordingly, the first direction D1 may be a direction in which the second frame <NUM> moves away from the first frame <NUM>, that is, moves outwardly of the mobile terminal <NUM> or the first frame <NUM>. On the other hand, during the movement in the second direction D2, the second frame <NUM> contracts to the first frame <NUM>. Thus, the second direction D2 is a direction opposite to the first direction D1, so that the second direction D2 may be a direction in which the second frame <NUM> moves to become closer to the first frame <NUM>, that is, moves inwardly of the mobile terminal <NUM> or the first frame <NUM>. When being moved in the first direction D1, such second frame <NUM> extends and applies a force to the portion of the display unit <NUM> disposed on the rear face of the mobile terminal <NUM>, so that the portion of the display unit <NUM> may be disposed on the front face of the mobile terminal <NUM>, and a region for such additional arrangement may be defined. Thus, the second frame <NUM> may convert the mobile terminal <NUM> into the second state with the display unit <NUM> with the relatively extended front face by moving in the first direction D1. On the other hand, when being moved in the second direction D2, the second frame <NUM> contracts into an original state thereof, and applies a force to the portion of the display unit <NUM> disposed on the front face of the mobile terminal <NUM> to return to the rear face of the mobile terminal <NUM> again. Thus, the second frame <NUM> may convert the mobile terminal <NUM> into the first state with the display unit <NUM> with the relatively contracted front face by moving in the second direction D2. Accordingly, the second frame <NUM> selectively exposes the display unit <NUM> to the front face of the mobile terminal <NUM> depending on the moving direction (i.e., the first or second direction D1 and D2). Accordingly, the mobile terminal <NUM> may be converted into the first or second state defined above.

During the expansion and the contraction in such first and second directions D1 and D2, the second frame <NUM> may overlap the first frame <NUM>, more precisely, the first front portion <NUM> and the first rear portion <NUM> thereof so as not to interfere with the first frame <NUM>. More specifically, the display unit <NUM> may be coupled to and supported by the first front portion <NUM> of the first frame <NUM>, as described above. Accordingly, the display unit <NUM> does not need to be additionally supported by the second front portion <NUM> of the second frame <NUM>. Rather, when the second front portion <NUM> is interposed between the first front portion <NUM> and the display unit <NUM>, the display unit <NUM> may be deformed or damaged because of friction with the second front portion <NUM>, which is repeatedly moved. Thus, the second front portion <NUM> may be disposed below the first front portion <NUM>, as shown in <FIG>. That is, a front face of the second front portion <NUM> may face the rear face of the first front portion <NUM>. In addition, the rear face of the first front portion <NUM> may be in contact with the front face of the second front portion <NUM> to stably support the movement of the second frame <NUM>.

The third rear portion <NUM> of the second frame <NUM> may be disposed below the second rear portion <NUM> of the first frame <NUM>. That is, the front face of the third rear portion <NUM> may face the rear face of the second rear portion <NUM>. In addition, the rear face of the second rear portion <NUM> may be in contact with the front face of the third rear portion <NUM> to stably support the movement of the second frame <NUM>. Because of such arrangement, the third rear portion <NUM> may be exposed to the outside of the first frame, more precisely, of the second rear portion <NUM>, and may be coupled to the display unit <NUM>.

Alternatively, when the second rear portion <NUM> is made of a transparent material, the second rear portion <NUM> may form an outer shape of the rear face of the mobile terminal. The second rear portion <NUM> may be positioned rearward of the third rear portion <NUM> of the second frame, and the flexible display unit may be disposed between the second rear portion <NUM> and the third rear portion <NUM> in the first state.

When the second rear portion <NUM> is made of a material such as a transparent glass to form the outer shape of the rear face of the mobile terminal, the first rear portion <NUM> may be implemented using the same member as the second rear portion <NUM>. That is, the camera <NUM>, the flash or the sensing unit <NUM>, and the like may be arranged by partially coating the plate-shaped member of the transparent glass material to not allow the internal components to be visible and by not coating only a required portion.

In addition, the second frame <NUM> may expand and contract the size of the mobile terminal <NUM> itself, particularly the front face of the mobile terminal <NUM> by the expansion and the contraction in the first and second directions D1 and D2. Thus, the display unit <NUM> must move by such extended or reduced front face size to obtain the intended first and second states. However, when being fixed to the second frame <NUM>, the display unit <NUM> may not be moved smoothly to be adapted for the front face of the mobile terminal <NUM> that is expanded or contracted. For this reason, the display unit <NUM> may be movably coupled to the second frame <NUM>. More specifically, the display unit <NUM> may include a first side edge (or side end) 151d disposed on the front face of the mobile terminal <NUM> and a second side edge 151e opposite to the first side edge 151d and disposed on the rear face of the mobile terminal <NUM>. The first side edge <NUM> may be disposed on the front face of the first frame <NUM>, that is, the front face of the first front portion <NUM> thereof, and may be disposed adjacent to the side portion of the mobile terminal <NUM>, that is, the first side portion 101a of the first frame. On the other hand, since the second side edge 151e is adjacent to the rear face of the mobile terminal <NUM> and the third rear portion <NUM> of the second frame <NUM>, the second side edge 151e may is be coupled the third rear portion <NUM> of the second frame <NUM> to be movable in the first and second directions D1 and D2. In addition, since the display unit <NUM> is not structurally strong, a third frame <NUM> may be coupled to the second side edge 151e. The third frame <NUM> may be formed of a plate-shaped member extending in the longitudinal direction of the mobile terminal <NUM>. Accordingly, the third frame <NUM> may be coupled to the second frame, that is, the third rear portion <NUM> thereof to be movable in the first and second directions D1 and D2 instead of the second side edge 151e. In addition, the second frame <NUM> may include a slot <NUM> extending in the lateral direction of the mobile terminal <NUM> or the second frame <NUM>, that is, the direction perpendicular to the longitudinal direction thereof. Further, the third frame <NUM> may be stably moved while being guided by the slot <NUM>. The third frame <NUM> may include, for example, a projection inserted into the slot <NUM> for the movement along the slot <NUM>.

Referring to <FIG>, in connection with such configuration of the first to third frames <NUM>, <NUM>, and <NUM>, the display unit <NUM> may include a first region <NUM> extending from one side thereof, that is, the first side edge 151d toward the second side edge 151e by a predetermined length, and a second region <NUM> disposed opposite the first region <NUM>, and extending from the second side edge 151e toward the first side edge 151d by a predetermined length. In addition, the display unit <NUM> may include a third region <NUM> disposed between the first and second regions <NUM> and <NUM>. Such first to third regions <NUM>, <NUM>, and <NUM> may be connected to each other, and may form a continuous body of the display unit <NUM>. In addition, as described above, for the movement of the third region <NUM> toward the front face or the rear face of the mobile terminal <NUM> depending on the moving direction of the second frame <NUM>, the first region <NUM> may be fixed so as not to move to the front face of the mobile terminal <NUM>, and the second region <NUM> may be provided to be movable on the rear face of the mobile terminal. Such configuration of the display unit <NUM> will be described in more detail below.

The first region <NUM> may be disposed on the front face of the mobile terminal <NUM>, more specifically, the first frame <NUM>, that is, on the front face of the first front portion <NUM>. The first region <NUM> is fixed to the first frame <NUM>, that is, the front face of the first front portion <NUM> so as not to be moved during the movement of the second frame <NUM>, and thus, the first region <NUM> may always be exposed to the front face of the mobile terminal <NUM>. The third region <NUM> may be adjacent to the first region <NUM>, and may extend into the second frame <NUM> and rolled on the roller <NUM>. The third region <NUM> may consecutively extend out of the second frame <NUM> again and partially cover the second frame <NUM>, that is, the rear face of the third rear portion <NUM>. Further, the second frame <NUM>, that is, the third rear portion <NUM>, is adjacent to the first frame <NUM>, that is, the second rear portion <NUM> and together forms the rear case of the mobile terminal <NUM>, so that it may be described that the third region <NUM> is also disposed on the rear face of the first frame <NUM>.

The second region <NUM> may be adjacent to the third region <NUM> and may be disposed on the rear face of the mobile terminal <NUM>, more specifically, on the second frame, that is, the rear face of the third rear portion <NUM> thereof. The second region <NUM> may be coupled to the third frame <NUM> without being directly coupled to the second frame <NUM>. As shown in <FIG>, the slot <NUM> extending in the lateral direction (i.e., the direction perpendicular to the longitudinal direction of the mobile terminal <NUM>) to the second frame <NUM>, that is, to the third rear portion <NUM> is defined. Further, the third frame <NUM> may move along the slot <NUM>. In <FIG>, it is shown that the slot <NUM> is defined in the rear face of the second frame <NUM>, but may be defined in the side face of the second frame <NUM>. Although the second region <NUM> may move in the first or second direction D1 or D2 with respect to the second frame <NUM> together with the third frame <NUM>, the movement of the second region <NUM> may be restricted within the rear face of the mobile terminal <NUM> by the slot <NUM>. That is, the second region <NUM> does not move out of the second frame <NUM> even when the second frame <NUM> is extended or contracted, and may move along the slot <NUM> within the second frame <NUM> by the extended or contracted distance of the second frame <NUM>. Accordingly, the second region <NUM> may always be exposed to the rear face of the mobile terminal <NUM>.

As a result, the first region <NUM> may be disposed on the front face of the mobile terminal <NUM> and may be always exposed to the front face regardless of the movement of the second frame <NUM>, and the second region <NUM> may be disposed on the rear face of the mobile terminal <NUM> and may be always exposed to the rear face regardless of the movement of the second frame <NUM>. In addition, the third region <NUM> may be disposed between the first and second regions <NUM> and <NUM>, and may be selectively placed on the front face or the rear face of the mobile terminal <NUM> depending on the moving directions D1 and D2 of the second frame <NUM>.

Because of such selective placement of the third region <NUM>, as shown in <FIG>, the second rear portion <NUM> of the first frame <NUM> is covered by the second and third regions <NUM> and <NUM> and the third rear portion <NUM> of the display unit <NUM> in the first state, but the third region <NUM> moves to the front face of the mobile terminal <NUM> in the second state, and the third rear portion <NUM> also moves in the first direction D1, so that the mobile terminal <NUM> may be exposed to the outside. In addition, the second front portion <NUM> of the second frame <NUM> is disposed below the first front portion <NUM> of the first frame <NUM> in the first state, but is moved out of the first frame <NUM> and supports the third region <NUM> of the display unit <NUM> disposed on the front face of the mobile terminal <NUM> in the second state.

Since the first and second regions <NUM> and <NUM> are always respectively arranged on the front face and the rear face of the mobile terminal <NUM>, curvatures of the first region <NUM> and the second region <NUM> do not change, and the first region <NUM> and the second region <NUM> may be maintained in a flat basic state. However, the third region <NUM> may be rolled on the roller <NUM> and bent in the second frame <NUM>. When converting from the first state to the second state, the third region <NUM> may extend from the second frame <NUM> to the front face of the mobile terminal <NUM> while being rolled on the roller <NUM> in one direction. On the other hand, when converting from the second state to the first state, the third region <NUM> may be retracted from the front face of the mobile terminal <NUM> to the second frame <NUM> while being rolled on the roller <NUM> in the opposite direction, and at the same time, may return to the rear face of the mobile terminal <NUM> from the second frame <NUM>. A specific location of the foldable mobile terminal in a form of being spread like a book is easily damaged because only the specific location is folded repeatedly. On the other hand, the deformed portion of the flexible display unit <NUM>, that is, a portion rolled on the roller <NUM>, may vary based on the first and second states of the mobile terminal <NUM>, that is, the movement of the second frame <NUM>. Accordingly, the mobile terminal <NUM> of the present disclosure may significantly reduce deformation and fatigue repeatedly applied to a specific portion of the display unit <NUM>, thereby preventing damage to the display unit <NUM>.

Based on the above-described configuration, overall operations of the mobile terminal <NUM> will be described as follows. As an example, the state conversion may be performed manually by the user, and an operation of the mobile terminal <NUM> during such manual state conversion will be described. However, operations of the first to third frames <NUM> to <NUM> and the display unit <NUM>, which will be described below, may be performed in the same manner when a power source other than a user's force is used, for example, when the driving unit <NUM> to be described below is applied.

As shown in <FIG>, <FIG>, and <FIG>, the second frame <NUM> is fully retracted into the first frame <NUM> in the first state. Therefore, only the first region <NUM> of the display unit <NUM> fixed to the front face of the first frame <NUM> may be exposed to the front face of the mobile terminal <NUM>. Such first region <NUM> may be fixed and supported to the first frame <NUM>, that is, the first front portion <NUM> thereof. In addition, a major portion of the third region <NUM> may be disposed on the rear face of the mobile terminal <NUM> together with the second region <NUM>, and the third region <NUM> may be disposed in the second frame <NUM> while being partially rolled on the roller <NUM>. The third region <NUM> of the rear face of the mobile terminal <NUM> may be supported by the second frame, that is, the third rear portion <NUM> thereof. The second region <NUM> may be fixed by the third frame <NUM> disposed on the second frame (i.e., the third rear portion <NUM>) and may be movably coupled to the second frame <NUM>.

In such first state, when the second frame <NUM> moves in the first direction D1, the mobile terminal <NUM> may be converted into the second state. As shown in <FIG>, <FIG>, and <FIG>, the second frame <NUM> may extend from the first frame <NUM> by the movement in the first direction D1, and may increase the overall size of the mobile terminal <NUM>, in particular, the front face thereof. During the movement in the first direction D1, the second frame <NUM> may apply a force, that is, a tension, to the display unit <NUM> in the first direction D1. The display unit <NUM> is fixed to the first frame <NUM> but is coupled to the second frame <NUM> so as to be movable using the third frame <NUM>, so that the force applied by the second frame <NUM> allows the third region <NUM> to be rolled out from the roller <NUM> of the second frame <NUM> to the front face of the mobile terminal <NUM>. That is, the third region <NUM> may be withdrawn (or pulled out) from the second frame <NUM> or extend to (or move out of) the second frame <NUM>. At the same time, the third region <NUM>, particularly, the portion located on the rear face of the third region <NUM> may be rolled into the roller <NUM> of the second frame <NUM> from the rear face, or may be inserted (or pushed in), retracted, or moved into the second frame <NUM>. Not an entirety of the third region <NUM> is withdrawn from the second frame <NUM> to the front face of the mobile terminal <NUM>, and a portion of the third region <NUM> may be disposed in the second frame <NUM> while still being rolled on the roller <NUM>. In addition, for the smooth movement of the third region <NUM>, the second region <NUM> may also move in the first direction D1 with respect to the second frame <NUM> together with the third frame <NUM>. In addition, as described above, the second region <NUM> and the third frame <NUM> may be constrained to the second frame <NUM> and move in the first direction D1 with respect to the first frame <NUM> together with the second frame <NUM>.

Accordingly, the second region <NUM> and the third frame <NUM> may move in the first direction D1 relative to the first frame <NUM> as well as the second frame <NUM>, and accordingly, move a distance longer than the moved distance of the second frame <NUM>. Thus, because of such long distance movement in the first direction D1 of the second region <NUM>, the third region <NUM> may be smoothly extended to the front face of the mobile terminal <NUM>. Further, for the movement of the third region <NUM>, which is proportional to the expansion of the second frame <NUM>, the movement of the second region <NUM> and the third frame <NUM> in the first direction D1 may be performed simultaneously with the movement of such third region <NUM> and second frame <NUM> in the first direction D1 so as to be proportional to the movement of third region <NUM> and second frame <NUM>.

When the second frame <NUM> is fully extended in the first direction D1, the first and third regions <NUM> and <NUM> may be arranged on the front face of the mobile terminal <NUM>, and only the second region <NUM> may be disposed on the rear face of the mobile terminal <NUM>. Such first and third regions <NUM> and <NUM> may be supported by the first frame (i.e., the first front portion <NUM> thereof) and the second frame (i.e., the second front portion <NUM> thereof). In addition, the second frame <NUM>, i.e., the third rear portion <NUM> thereof exposes the second rear portion <NUM> of the first frame while extending in the first direction D1, and supports the moving third region <NUM>. Therefore, in the second state, the mobile terminal <NUM> may have the extended front face display unit <NUM>.

On the other hand, when the second frame <NUM> moves in the second direction D2 in the second state, the mobile terminal <NUM> may again return into the first state as shown in <FIG>, <FIG>, and <FIG>. The second frame <NUM> may be contracted to the first frame <NUM> by the movement in the second direction D2, and may reduce the overall size of the mobile terminal <NUM>, particularly the front face thereof. The movement of the display unit <NUM> during such movement of the second frame <NUM> may be performed in a reverse order of the movement in the first direction D1 described above. In brief, the third region <NUM> may be rolled from the front face of the mobile terminal <NUM> into the roller <NUM> of the second frame <NUM>, or may be inserted, retracted, or moved into the second frame <NUM>. At the same time, the third region <NUM> may be rolled, withdrawn, extended, or moved out of the roller <NUM> of the second frame <NUM> to the rear face of the mobile terminal <NUM>. Not the entirety of the third region <NUM> may be withdrawn from the second frame <NUM> to the rear face of the mobile terminal <NUM>, and the portion of the third region <NUM> may still be placed in the second frame <NUM> while still being rolled on the roller <NUM>. In addition, for such smooth movement of the third region <NUM>, the second region <NUM> may also move in the second direction D2 with respect to the second frame <NUM> together with the third frame <NUM>. The second region <NUM> and the third frame <NUM> may be constrained to the second frame <NUM> to move in the second direction D2 with respect to the first frame <NUM> together with the second frame <NUM>. Accordingly, the second region <NUM> and the third frame <NUM> may move relatively in the second direction D2 with respect to not only the second frame <NUM> but also the first frame <NUM>. As a result, the second region <NUM> and the third frame <NUM> may move in the second direction D2 a distance larger than the moved distance of the second frame <NUM>. Thus, because of such long distance movement of the second region <NUM>, the third region <NUM> may be smoothly returned to the rear face of the mobile terminal <NUM>. Further, for the movement of the third region <NUM> proportional to the contraction of the second frame <NUM>, the movements of the second region <NUM> and the third frame <NUM> in the second direction D2 may be performed simultaneously with the movements of the third region <NUM> and the second frame <NUM> in the second direction D2 to be proportional to the movements of the third region <NUM> and the second frame <NUM>. When the second frame <NUM> is completely contracted in the second direction D2, the mobile terminal <NUM> may be converted into the first state as described above, and may have the display unit <NUM> with the front face that is relatively reduced in comparison with the second state in the first state.

The flexible display unit <NUM> has one surface that is exposed outside and on which an image is output, and another surface, which may be coupled to a frame that supports the flexible display unit <NUM>.

The first region of the flexible display unit <NUM> is supported by the first frame <NUM>, and the second region of the flexible display unit <NUM> is supported by the third frame <NUM>. However, the third region is not directly coupled to the first to third frames <NUM>, <NUM>, and <NUM> constituting the body of the mobile terminal. Since the third region, that is, the variable portion, has a variable curvature depending on a bending position or bending deformation, a support frame <NUM> having a variable curvature corresponding thereto is needed.

<FIG> is an enlarged view of the support frame <NUM> of the mobile terminal according to one embodiment of the present disclosure. The support frame <NUM> supports the other surface of the variable portion of the flexible display unit <NUM>, thereby enabling stable touch input even on the variable portion and preventing the variable portion from being damaged by an external force.

The second front portion <NUM> of the second frame is inside the first front portion <NUM> of the first frame in the first state. When the second front portion <NUM> moves in the first direction so as to be switched to the second state, a gap corresponding to the thickness of the first front portion <NUM> is generated between the flexible display unit <NUM> and the second front portion <NUM>. When the support frame <NUM> having a thickness corresponding to the gap is employed, a problem in which the front portion of the flexible display unit <NUM>, which is extended in the second state, becomes spaced apart from the second front portion <NUM> may be solved.

The support frame <NUM> may include a plurality of rigid bars <NUM> disposed in the third direction and a flexible portion <NUM> connecting the rigid bars <NUM>. The rigid bars <NUM> may be made of a material having rigidity, such as a metal material, and may support the other surface of the third region of the flexible display unit <NUM>. The flexible portion <NUM> may be made of a flexible material such as silicon, and may be deformed when the flexible display unit <NUM> is wound around the roller.

A part of the flexible portion <NUM> may be smaller in thickness than the rigid bar <NUM> so as to enable the flexible portion <NUM> to be easily deformed. The thin part of the flexible portion <NUM> may be a groove <NUM> extending in the third direction, as illustrated in <FIG>. The groove <NUM> may be provided in a plural number, and may be arranged side by side in the first direction. The grooves <NUM>, formed in the rear surface of the support frame <NUM>, and a protruding portion, positioned between the grooves <NUM>, form a flexible rack gear <NUM>.

The roller <NUM> is formed, on the outer circumferential surface thereof, with an uneven surface corresponding to the flexible rack gear <NUM>. Accordingly, when the roller <NUM> rotates, the flexible display unit <NUM> may move along with the roller <NUM> without sliding thereon.

When the mobile terminal is switched from the first state to the second state or vice versa and changes in size in the first or second direction, the area of the flexible display unit <NUM> that is located on the front surface and the area of the flexible display unit <NUM> that is located on the rear surface also change in size. In the case of switching from the first state to the second state, the roller <NUM> rotates while the second frame <NUM> moves in the first direction, and naturally, the area of the flexible display unit <NUM> that is located on the rear surface decreases and the area of the flexible display unit <NUM> that is located on the front surface increases. Conversely, in the case of switching from the second state to the first state, when the second frame <NUM> moves in the second direction, the flexible display unit <NUM> should also move correspondingly at the same speed.

When switching from the first state to the second state, the flexible display unit <NUM> may move together with the second frame <NUM>. However, when switching from the second state to the first state, the flexible display unit <NUM> may not move together with the second frame in the second direction, whereby the flexible display unit <NUM> may lift, and may interfere with the movement of the second frame <NUM> in the second direction.

For this reason, when switching from the second state to the first state, force for pulling the flexible display unit <NUM>, located on the front surface, in the first direction and moving the same to the rear surface is needed. In order to keep the flexible display unit <NUM> flat even after the transition from the first state to the second state is completed, force for pulling the flexible display unit <NUM>, located on the front surface, in the first direction is needed.

In order to keep the flexible display unit <NUM> flat and to easily switch from the second state to the first state, the mobile terminal <NUM> of the present disclosure may further include an auxiliary driving unit <NUM> configured to apply force to the flexible display unit <NUM>, in addition to the driving unit <NUM> configured to move the second frame <NUM>.

<FIG> shows front face views respectively illustrating the first state and the second state without the flexible display unit <NUM> of the mobile terminal <NUM> according to one embodiment of the present disclosure, and the auxiliary driving unit <NUM> coupled to the second frame <NUM> is included in the drawing. The auxiliary driving unit <NUM> of this embodiment may further include a motor <NUM> coupled to the second frame <NUM>, a pinion gear <NUM> rotated by receiving the rotational force of the motor <NUM>, and a flexible rack gear <NUM> formed on the support frame <NUM>. In order to secure space for mounting components such as the battery <NUM>, the motor <NUM> and the pinion gear <NUM> may be disposed so as to be biased in the first direction on the first frame.

The pinion gear <NUM> may be disposed so as to come into contact with the flexible rack gear <NUM> formed on the rear surface of the support frame <NUM>. The flexible rack gear <NUM> may provide tensile force acting in the first direction, which is generated by the flexible rack gear <NUM> being engaged with the pinion gear <NUM> and receiving the force of the motor <NUM> through the pinion gear <NUM>, to the flexible display unit.

<FIG> shows the first frame <NUM> and the second frame <NUM> of the mobile terminal <NUM> according to the present disclosure. The driving unit <NUM>, configured to move the second frame <NUM> in the first direction or in the second direction with respect to the first frame <NUM>, may include a motor <NUM>, a rack gear <NUM> extending in a linear direction, and a pinion gear <NUM> rotated by receiving the rotational force of the motor <NUM>. The motor <NUM> and the pinion gear <NUM> are coupled to the first frame <NUM>, and the rack gear <NUM> is located on the second frame <NUM>.

The auxiliary driving unit <NUM> also includes the motor <NUM> and the pinion gear <NUM>. However, the difference between the driving unit <NUM> and the auxiliary driving unit <NUM> is that the auxiliary driving unit <NUM> is fixed to the second frame <NUM>, and rotates by being meshed with the flexible rack gear <NUM> of the support frame <NUM>, which is located at the rear surface of the flexible display unit <NUM>. In order to avoid interference with the driving unit <NUM>, the auxiliary driving unit <NUM> may be disposed between a pair of driving units <NUM> respectively disposed on opposite sides in the third direction (the up-down direction in the drawing) as illustrated in <FIG> and <FIG>.

<FIG> shows cross-sectional views respectively taken along a line C-C and a line D-D of <FIG>. Hereinafter, the operation of the auxiliary driving unit <NUM> in the first state and in the second state will be described in more detail. The support frame <NUM> may have the flexible rack gear <NUM> formed on the other surface thereof, which is opposite one surface thereof to which the display panel is coupled. The flexible rack gear <NUM> is a gear having a toothed portion thereof, extending in a linear direction rather than being formed on a circumferential surface of a disk. Since the flexible rack gear <NUM> is made of a flexible material, when the variable portion of the flexible display unit <NUM> is curved in a direction from the front face to the rear face, the flexible rack gear <NUM> may be deformed while forming a curved surface.

The flexible rack gear <NUM> includes the grooves <NUM> extending in the third direction. The grooves <NUM> are arranged side by side in the first direction. The grooves <NUM> may be formed in the flexible rack gear <NUM> such that the flexible portion <NUM> positioned between the rigid bars <NUM> in the above-described support frame <NUM> is formed to have a small thickness. When the pinion gear <NUM> in mesh with the grooves <NUM> in the flexible rack gear <NUM> rotates and, the flexible rack gear <NUM> moves, whereby the area of the flexible display unit <NUM> that is located on the front surface may change.

The pinion gear <NUM> is fixed to the second frame <NUM> and rotates by receiving the force of the motor <NUM>. The pinion gear <NUM> may not be directly connected to the motor <NUM>, and may further include, in a center thereof, a gear that transmits the rotational force.

When the mobile terminal <NUM> of the present disclosure is switched from the first state (<FIG>) to the second state (<FIG>), the second frame <NUM> moves in the first direction, and the area of the flexible display unit <NUM> that is located on the front surface increases. Here, because the pinion gear <NUM>, which is in contact with the flexible rack gear <NUM>, changes in position, the pinion gear <NUM> rotates counterclockwise.

When the mobile terminal <NUM> is switched from the first state to the second state, the front surface of the flexible display unit <NUM> is expanded as the second frame <NUM> moves, whereby the pinion gear <NUM>, which is meshed with the flexible rack gear <NUM>, rotates. When switching from the first state to the second state, the motor <NUM> of the auxiliary driving unit <NUM> may not operate, since the motor <NUM> does not need to provide a force, and only the pinion gear <NUM> may rotate.

The pinion gear <NUM> rotates independently of the motor <NUM> during counterclockwise rotation. The motor may be engaged with the pinion gear <NUM> in order to transmit only the clockwise rotational force of the motor <NUM>.

When the transition to the second state is completed, as illustrated in <FIG>, the motor <NUM> rotates in the reverse direction to rotate the pinion gear <NUM> clockwise and applies a force (tensile force) to the flexible rack gear <NUM> in the first direction. When the movement of the second frame <NUM> in the first direction is completed, the area of the flexible display unit <NUM> that is located on the front surface may be flattened by rotating the pinion gear <NUM> slightly in the reverse direction.

While the mobile terminal <NUM> is being switched from the second state to the first state, even if the driving unit moves the second frame <NUM> in the second direction, the flexible display unit <NUM> located on the front surface may not move to the rear face of the mobile terminal <NUM>, but may lift or become wrinkled on the second frame <NUM> or the first frame <NUM>.

For this reason, when the mobile terminal <NUM> is switched from the second state to the first state (when switched from <FIG>), the motor <NUM> of the auxiliary driving unit <NUM> may rotate the pinion gear <NUM> clockwise so as to push the flexible rack gear <NUM> rightwards (first direction) in the drawing. The end portion in the first direction of the flexible display unit <NUM> located on the front surface may move toward the rear surface of the mobile terminal <NUM>, thereby reducing the area of the flexible display unit <NUM> that is located on the front surface.

Here, the length that the flexible display unit <NUM> is moved by the auxiliary driving unit <NUM> and the distance that the second frame <NUM> moves in the second direction should be the same in order to stably switch the mobile terminal from the second state to the first state.

<FIG> shows front face views respectively illustrating the first state and the second state, without a display unit of a mobile terminal <NUM> according to another embodiment of the present disclosure, <FIG> is a view illustrating a roller <NUM> and an auxiliary driving unit <NUM> according to the embodiment of <FIG>, and <FIG> shows a cross-sectional view taken along a line E-E of <FIG>. The auxiliary driving unit <NUM> of this embodiment may be mounted inside the roller <NUM>.

The roller <NUM> is a bar-shaped member, which is coupled to a second frame <NUM> and has a circular cross-section, and is elongated in the third direction. The roller <NUM> serves to divide the flexible display unit <NUM> into a portion located on the front surface and a portion located on the rear surface, and serves to curve the flexible display unit <NUM> in a direction from the front face to the rear face of the mobile terminal <NUM> while forming a curved surface.

The roller <NUM> of this embodiment has a pinion gear <NUM> formed on the outer surface thereof. The roller <NUM> may be rotated by the engagement between the pinion gear <NUM> and the flexible rack gear <NUM>. The pinion gear <NUM> located on the outer circumferential surface of the roller <NUM> prevents the flexible display unit <NUM> from sliding on the roller <NUM> so as to synchronize the rotation of the roller <NUM> and the movement of the flexible display unit <NUM>.

The roller <NUM> of this embodiment may include a first portion 1028a, the interior of which is filled, and a second portion 1028b, having a hollow 1028c formed therein. The second portion 1028b is disposed adjacent to the first portion 1028a in the third direction. The second portion 1028b may be disposed at only one side of the first portion 1028a, but may also be disposed on each of opposite sides of the first portion 1028a as shown in <FIG> so as to provide a uniform force.

The second portion 1028b may be positioned at each of opposite ends of the roller <NUM> and may have an elastic part <NUM> disposed therein. One end of the elastic part <NUM> is coupled to a first fastening portion <NUM>, which is positioned at a boundary between the first portion 1028a and the second portion 1028b. The other end of the elastic part <NUM> is coupled to a second fastening portion <NUM>, which is provided on the second frame <NUM>. The first fastening portion <NUM> is located in the hollow 1028c formed inside the second portion 1028b of the roller <NUM>. Therefore, in order to fasten the one end of the elastic part <NUM> to the first fastening portion <NUM>, the second portion 1028b may have an opening 1028d exposing the first fastening portion <NUM>.

As illustrated in <FIG>, the second fastening portion <NUM> is fixed to the second frame <NUM> and protrudes toward the hollow 1028c. The roller <NUM> is rotatably fastened to the second frame <NUM> so that the roller <NUM> is rotatable about the second fastening portion <NUM>. The roller <NUM> may further include a screw <NUM>, configured to fasten the second fastening portion <NUM> to the second frame <NUM>.

Since the first fastening portion <NUM> rotates together with the roller <NUM> and the second fastening portion <NUM> is fixed to the second frame <NUM>, the elastic part <NUM> is deformed when switched from the first state to the second state. The elastic part <NUM> has elastic force for returning to the first state, and thus, when switched from the second state to the first state, the roller <NUM> rotates in the direction in which the flexible display unit <NUM> is moved to be located on the rear surface.

A coil spring illustrated in <FIG> may be used as the elastic part <NUM>. When switching from the first state to the second state, the number of turns of the coil spring is changed while the roller <NUM> rotates, thereby generating elastic force for rotating in a direction opposite the direction of switching from the first state to the second state. Therefore, the area of the flexible display unit <NUM> that is located on the front surface may be reduced as the roller <NUM> rotates corresponding to the distance that the second frame <NUM> moves when switched from the second state to the first state.

In addition, even when the mobile terminal is in the second state, the roller <NUM> may provide tensile force due to the elasticity of the elastic part <NUM>, which is a force switching the mobile terminal from the second state to the first state, thereby keeping the flexible display unit <NUM> flat.

The auxiliary driving unit <NUM> of the embodiment of <FIG> and the auxiliary driving unit <NUM> of the embodiment of <FIG> may be both implemented in one mobile terminal. Alternatively, the auxiliary driving unit <NUM> may be implemented to have a structure in which the auxiliary driving unit <NUM> of <FIG> further includes only the pinion gear <NUM> of <FIG>, which is formed on the outer circumferential surface of the roller <NUM>.

As described above, in the mobile terminal <NUM> of the present disclosure, the flexible display unit <NUM> may also stably move corresponding to the movement of the second frame <NUM>. In addition, due to the tensile force provided to the flexible display unit <NUM>, the flexible display unit <NUM> may remain flat without lifting, and may remain in close contact with the body of the mobile terminal.

Claim 1:
A mobile terminal comprising:
a body comprising a first frame (<NUM>), and a second frame (<NUM>) coupled to the first frame (<NUM>) so as to be movable in a first direction with respect to the first frame (<NUM>);
a roller (<NUM>) rotatably coupled to the second frame (<NUM>);
a flexible display unit (<NUM>) divided, by being rolled around the roller (<NUM>), into a front portion located on a front surface of the body and a rear portion located on a rear surface of the body, and configured to output an image on one surface thereof;
a support frame (<NUM>) coupled to another surface of the flexible display unit (<NUM>) and comprising a flexible rack gear (<NUM>) formed on another surface of the support frame (<NUM>); and
an auxiliary driving unit (<NUM>) adapted to transfer a force to the flexible rack gear (<NUM>) in a direction in which a size of an area of the flexible display unit (<NUM>) that is located on the rear surface increases,
wherein the auxiliary driving unit (<NUM>) comprises:
a pinion gear (<NUM>) that is adapted to rotate by being meshed with the flexible rack gear (<NUM>);
a motor (<NUM>), which is coupled to the second frame (<NUM>) and is configured to provide rotational force to the pinion gear (<NUM>);
wherein the pinion gear (<NUM>) is configured to rotate in a first rotational direction when the second frame (<NUM>) moves in the first direction; and
wherein the motor (<NUM>) is configured to:
rotate the pinion gear (<NUM>) in a second rotational direction, which is opposite the first rotational direction, when the second frame (<NUM>) moves in a second direction; and
rotate the pinion gear (<NUM>) by a predetermined angle in the second rotational direction, which is opposite the first rotational direction, so as to provide tensile force to the flexible display unit (<NUM>) in the first direction, when the second frame (<NUM>) finishes moving in the first direction.