US20070284494A1

US20070284494A1 - Display extension unit

Info

Publication number: US20070284494A1
Application number: US11/730,328
Authority: US
Inventors: Dong-Won Choi; Jae-Kyung Kim; Chi-Sung Lee; Kyoung-shin Park
Original assignee: Samsung Electro Mechanics Co Ltd
Current assignee: Samsung Electro Mechanics Co Ltd
Priority date: 2006-04-13
Filing date: 2007-03-30
Publication date: 2007-12-13
Also published as: JP2007288782A; EP1845301A3; EP1845301A2; KR100801251B1; KR20070101955A; CN101055774A

Abstract

The present invention relates to a display extension unit. The display extension unit includes a fixed body, a link portion having one end coupled to the fixed body; a movable body coupled to the other end of the link portion, and a driving part coupled to the joining point of the link portion, where the driving part includes a motor unit and a rotary part coupled to the driving shaft of the motor unit, with the rotary part including a clutch coupled to the driving shaft and a driven shaft positioned in contact with the clutch, and where the driving force of the motor unit is smaller than the frictional force between the driven shaft and the clutch.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2006-0033453 filed with the Korean Intellectual Property Office on Apr. 13, 2006, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field
The present invention relates to a display extension unit, and in particular, to a display extension unit which enables the flat panel display to rotate in a desired angle.
2. Description of the Related Art
Due to the benefit of allowing efficient use of spaces, flat panel displays such as LCD, PDP, LED applied in TV's and monitors are replacing CRT TV and monitors, and the demand for these displays are expected to steadily increase. Flat panel LCD or PDP TV's, in particular, are typically mounted on a wall, and are hence also known as “wall-mount TV's.” When using a wall mount TV, the largest viewing angle may be achieved just in front of the TV. Adequate viewing may not be achieved from a different position, when the TV is mounted on a wall in a fixed orientation.
It is difficult to modify the TV's position with the conventional wall-mount TV, because there is little or no distance between the TV and the wall. Also, it is not possible to rotate the TV to a desired direction even when a sufficient distance is provided by means of additional members.
In addition, solving such problems by applying an apparatus to maintain a fixed distance may result in another problem, i.e. degrading the elegant appearance and the efficiency in utilizing an indoor space.

SUMMARY

Certain aspects of the present invention aim to provide a display extension unit which enables the largest viewing angle for different positions, to maintain the efficiency of the wall-mount TV in utilizing an indoor space.
In addition, one aspect of the present invention provides a display extension unit having a safety unit that prevents excessive loads on the motor not only when operated automatically but also when operated manually.
One aspect of the present invention provides a display extension unit that includes a fixed body, a link portion having one end coupled to the fixed body, a movable body coupled to the other end of the link portion, and a driving part coupled to the joining point of the link portion, where the driving part includes a motor unit, and a rotary part coupled to the driving shaft of the motor unit, with the rotary part including a clutch coupled to the driving shaft, and a driven shaft positioned in contact with the clutch, and where the driving force of the motor unit is smaller than the frictional force between the driven shaft and the clutch.
The frictional force between the driven shaft and the clutch may be smaller than the cogging torque of the motor unit. The display extension unit may further include one or more washers interposed between the clutch and driven shaft.
The link portion may include a first hinge member coupled to the fixed body, a second hinge member coupled to the movable body, a first link element having one end rotatably coupled to the first hinge member, and a second link element having one end rotatably coupled to the second hinge member.
The motor unit may be coupled to the first hinge member or the second hinge member, and the rotary part may be coupled to the first link element or the second link element, with the first link element and the second link element coupled in correspondence with the first hinge member and the second hinge member, respectively.
The link portion may include a first guide member coupled to the fixed body while separated from the first hinge member, and a second guide member coupled to the movable body while separated from the second hinge member, where the first link element and the second link element may intersect, and the other end of the first link element may be coupled to be movable along the second guide element, and the other end of the second link element may be coupled to be movable along the first guide element.
The driving part may be coupled to the part where the first link element and the second link element intersect, the motor unit may be coupled to the first link element or the second link element, and the rotary part may be coupled to that one of the first link element and the second link element to which the motor unit is not coupled.
The link portion may include a third hinge member coupled to the fixed body while separated from the first link element, a fourth hinge member coupled to the movable body while separated from the second link element, a third link member having one end rotatably coupled to the other end of the first link member with an interposed fifth hinge member and having the other end rotatably coupled to the fourth hinge member, and a fourth link member having one end rotatably coupled to the other end of the second link member with an interposed sixth hinge member and having the other end rotatably coupled to the third hinge member.
The display extension unit may further include a first gear coupled to the outer perimeter of the first hinge member, and a second gear coupled the first gear and the outer perimeter of the third hinge member. The first gear and the second gear may be coupled by an even number of idle gears. The rotary part may be coupled to the first gear or the second gear.
Another aspect of the present invention provides a display extension unit that includes a fixed body, a link portion which includes a first link arm and a second link arm respectively having one end coupled to the fixed body, a movable body coupled to the other end of the first link arm or the second link arm, and a driving part coupled to the first link arm or the second link arm, where the driving part includes a motor unit coupled to the first link arm or the second link arm, a driving shaft having one end coupled to the motor unit to rotate, a pipe having a penetration hole with the other end of the driving shaft inserted through one side of the penetration hole, and a fixed shaft having one end inserted through the other side of the penetration hole and having the other end coupled to the first link arm or the second link arm in correspondence with the motor unit.
The one side of the penetration hole and the other end of the rotary shaft may be coupled by guide-joining or screw-joining, and the other side of the penetration hole and the one end of the fixed shaft may be coupled by guide-joining or screw-joining in correspondence with the joining of the one side of the penetration hole and the other end of the rotary shaft.
Another aspect of the present invention provides a display extension unit that includes a fixed body, a link portion having one end coupled to the fixed body, a movable body coupled to the other end of the link portion, and a driving part coupled to the joining point of the link portion, where the driving part includes a motor unit and a rotary part coupled to the driving shaft of the motor unit, and the rotary part includes a clutch coupled to the driving shaft and a driven shaft positioned in contact with the clutch, and where the driving force of the motor unit is smaller than the frictional force between the driven shaft and the clutch.
The frictional force between the clutch and driven shaft is smaller than the cogging torque of motor unit, to prevent the motor unit from rotating when the driven shaft is rotated forcibly. One or more washers may be positioned between the clutch and the driven shaft to maintain a constant frictional force.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 a is a plan view of a display extension unit based on a first disclosed embodiment of the present invention.

FIG. 1 b is an enlarged cross-sectional view of the intersection portion in FIG. 1 a.

FIG. 1 c is an illustration of a display extension unit in operation based on a first disclosed embodiment of the present invention.

FIG. 2 a is a plan view of a display extension unit based on a second disclosed embodiment of the present invention.

FIG. 2 b is an illustration of a display extension unit in operation based on the second disclosed embodiment of the present invention.

FIG. 3 a is a plan view of a display extension unit based on a third disclosed embodiment of the present invention.

FIG. 3 b is an illustration of a display extension unit in operation based on the third disclosed embodiment of the present invention.

FIG. 4 a is a plan view of a display extension unit based on a fourth disclosed embodiment of the present invention.

FIG. 4 b is an illustration of a display extension unit in operation based on the fourth disclosed embodiment of the present invention.

FIG. 5 is a plan view of a display extension unit based on a fifth disclosed embodiment of the present invention.

FIG. 6 is a cross-sectional view of a rotary part of a driving part based on a sixth disclosed embodiment of the present invention.

FIG. 7 a is a plan view of a display extension unit based on a seventh disclosed embodiment of the present invention.

FIG. 7 b is a cross-sectional view of a pipe of a display extension unit based on the seventh disclosed embodiment of the present invention.

FIG. 7 c is a cross-sectional view across the dashed section A in FIG. 7 b.

DETAILED DESCRIPTION

Embodiments of the display extension unit according to the invention will be described below in more detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, those components are rendered the same reference number that are the same or are in correspondence, regardless of the figure number, and redundant explanations are omitted.
FIG. 1 a is an illustration of a display extension unit based on the first disclosed embodiment of the present invention. FIG. 1 b is an enlarged cross-sectional view of the intersection portion in FIG. 1 a. FIG. 1 c is an illustration of a display extension unit in operation based on the first disclosed embodiment of the present invention. Referring to FIG. 1 a-c, there are shown a link portion 10, fixed body 11, movable body 12, first hinge member 13 a, second hinge member 13 b, first guide member 14 a, second guide member 14 b, first link member 15 a, second link member 15 b, intersection portion 16, universal joint 17, display 18, driving part 19, motor unit 19 a, and rotary part 19 b.
While the fixed body 11, for supporting the link portion 10 and the movable body 12, is shown in an arbitrary form in the following drawings and descriptions, it shall be understood as including such forms of media as anchor bolts, brackets, and angles that can be used for coupling between the link portion 10 and a wall, etc. The fixed body 11 must be strong enough to sustain the total weight of the link portion 10, the movable body 12, and the display 18.
The link portion 10 includes a first hinge member 13 a, second hinge member 13 b, first guide member 14 a, second guide member 14 b, first link member 15 a, second link member 15 b and intersection portion 16.
The first hinge member 13 a is coupled to the fixed body 11 and hinge-joined to the one end of the first link member 15 a. The first guide member 14 a is coupled to the fixed body 11 at a point separated from the first hinge member 13 a. A hole in the first guide member 14 a enables the joined one end of the second link member 15 b to move in a straight line.
The second link member 15 b is hinge-joined with the first link member 15 a also at the intersection portion 16. The intersection portion 16 is the center portion of the first link member 15 a and the second link member 15 b. The driving part 19 coupled to the intersection potion 16 enables the first and the second link members 15 a, 15 b to rotate.
Meanwhile, the other end of the first link member 15 a moves in a straight line, being joined to the hole of the second guide member 14 b, and the other end of the second link member 15 b is hinge-joined to the movable body 12.
This second guide member 14 b may be formed as a single body with the movable body 12 as in FIG. 1 a and also may be joined as a separate body. The universal joint 17 is coupled to the movable body 12, whereby the display 18 joined to the universal joint 17 may move freely.
FIG. 1 b is an enlarged cross-sectional view of the intersection portion 16 in FIG. 1 a. At the intersection portion 16, the rotary part 19 b of the driving part 19 is coupled to the first link member 15 a, and the motor unit 19 a of the driving part 19 is coupled to the second link member 15 b. Thus, the rotation of the rotary part 19 b causes the first link member 15 a and second link member 15 to rotate about the intersection portion 16, and in consequence the movable body 12 coupled to the link portion 10 draws closer to or further away from the fixed body 11 as in FIG. 1 c. The motor unit 19 a may be coupled to the first link member 15 a, and the rotary part 19 b may be coupled to the second link member 15 b.
FIG. 2 a is a plan view of a display extension unit based on a second disclosed embodiment of the present invention. FIG. 2 b is an illustration of a display extension unit in operation based on the second disclosed embodiment of the present invention. As the second embodiment differs from the first embodiment only in the position of the driving part 29, the functions of the other components are similar in both embodiments, and the following description will be focused on the differences.
In this embodiment, the driving part 29 includes a motor unit 29 a and an expansion part 29 c coupled to the driving shaft 29 b of the motor unit 29 a which can be contracted in a longitudinal direction as the driving shaft 29 b rotates. As illustrated in the drawing, the motor unit 29 coupled to first guide member 24 a is coupled to one end of second link member 25 b. As the driving shaft 29 b rotates, the expansion and contraction of the expansion part 29 c result in the displacement of the link portion 20 by displacing one end of the second link member 25 b in a line. The motor unit 29 may be coupled to second guide member 24 b. FIG. 2 b illustrates an extended link portion 20 based on this embodiment
FIG. 3 a is a plan view of a display extension unit based on third disclosed embodiment of the present invention. FIG. 3 b is an illustration of a display extension unit in operation based on the third disclosed embodiment of the present invention. Referring to FIGS. 3 a to 3 b, there are shown a link portion 30, fixed body 31, movable body 32, first hinge part 34 a, second hinge part 34 b, third hinge part 34 c, fourth hinge part 34 d, first link member 35 a, second link member 35 b, universal joint 37, display 38, and driving part 39.
In the third embodiment, one end and the other end of the first link member 35 a and the second link member 35 b are respectively hinge-joined to the movable body 32 and the fixed body 31. As they rotate about the hinge parts 34 a-d, the movable body 32 swings in an arbitrary angle.
Meanwhile, the driving part 39 may be coupled to one of the four hinge parts 34 a-34 d. The driving part 39 includes a motor unit 19 a and a rotary part 19 b as illustrated in FIG. 1 b, and the first link member 35 a and second link member 35 b move freely simultaneously by the rotational force of the rotary part 19 b. While in this embodiment the driving part 39 is coupled to the first hinge member 34 a, it may also be coupled to one of the other three hinge members 34 b-34 d.
FIG. 3 b illustrates the first and second link members 35 a, 35 b extended by a swinging action. The functions of the other components in this embodiment are similar to those described in the first embodiment.
FIG. 4 a is a plan view of a display extension unit based on the fourth disclosed embodiment of the present invention. FIG. 4 b is an illustration of a display extension unit in operation based on the fourth disclosed embodiment of the present invention. Referring to FIGS. 4 a to 4 b, there are shown a link portion 40, fixed body 41, movable body 42, first hinge member 43 a, second hinge member 43 b, first link member 45 a, second link member 45 b, third link member 45 c, fourth link member 45 d, fifth link member 45 e, sixth link member 45 f, universal joint 47, display 48, driving part 49, motor unit 49 a, and worm gear member 49 c.
In this embodiment, the first and second hinge members 43 a, 43 b are coupled to the fixed body 41 with a constant amount of separation. The first link member 45 a and second link member 45 b each have one end hinge-joined to the first and second hinge members 43 a, 43 b, respectively, whereby rotation is enabled. In addition, There is hinge-joining between the other end of the first and second link members 45 a, 45 b and one end of the third and fourth link members 45 c, 45 d, respectively, between the other end of the third and fourth link member 45 c, 45 d and one end of the fifth and sixth link members 45 e, 45 f, respectively, and between the other end of the fifth and sixth link members 45 e, 45 f and the movable body 42.
In this embodiment, the driving part 49 includes a motor unit 49 a, rotary part (not shown in drawing) and worm gear member 49 c, where the motor unit 49 a is fixed to the fourth link member 45 d, and the worm gear member 49 c is screw-joined through the third link member 45 c as a threaded pipe. In accordance with the rotation direction of the worm gear member 49 c powered by the rotary part (not shown in drawing), the third link member 45 c and the fourth link member 45 d draw closer together or further apart. Consequently, the link portion 40 is extended or contracted. FIG. 4 b illustrates the link portion 40 being extended as the third link member 45 c and fourth link member 45 d draw closer. In addition, the same function may be achieved with the motor unit 49 a fixed to the third link member 45 c and the worm gear member 49 c coupled to the fourth link member 45 d. The functions of other components in this embodiment are similar to those of the first embodiment, and will not be described in further detail herein.
Although six link members are utilized in this embodiment, alternate configurations may be used, such as with four link members hinge joined in a lozenge shape, and with a driving part 49 and a worm gear member 49 c as in FIG. 4 a.
FIG. 5 is a plan view of a display extension unit based on the fifth disclosed embodiment of the present invention. Referring to FIG. 5, there are shown a link portion 50, fixed body 51, movable body 52, first hinge member 54 a, second hinge member 54 b, third hinge member 54 c, fourth hinge member 54 d, fifth hinge member 54 e, sixth hinge member 54 f, first link member 55 a, second link member 55 b, third link member 55 c, fourth link member 55 d, universal joint 57, idle gear 59 c, and display extension unit 500.
The display extension unit uses two pairs of link members in this embodiment. One end of each of the first link member 55 a and the second link member 55 b is hinge-joined to the first and second hinge members 54 a, 54 b, respectively, to enable rotation about the central axis in an arbitrary angle. The first and second hinge members 54 a, 54 b are coupled to the fixed body 51. The other end of each of the first link member 55 a and second link member 55 b, one end of each of the third link member 55 c and fourth link member 55 d, the other end of each of the third link member 55 c and fourth link member 55 d, and the movable body 52 are coupled to the correspondent hinge member 54 c-f, respectively.
While the link members can be driven by the driving part 59 coupled to one of the hinge members 54 a-f, in this embodiment, the link portion 50 is driven by positioning an even number of idle gears 59 c between the first gear 541 a and second gear 541 b formed on the first hinge member 54 a and second hinge member 54 b, respectively, and coupling the driving part (not shown in drawing) to any one of the first gear 541 a, the second gear 541 b, and the even number of idle gears 59 c.
The even number of idle gears 59 c operate the link members smoothly by alternating the rotation direction of the first gear 541 a and the second gear 541 b and prevent excessively high loads in one link member by driving the first and second link members 55 a, 55 b with the same force.
In this embodiment, the first gear 541 a and second gear 541 b are coupled to the first hinge member 54 a and second hinge member 54 b, and the even number of idle gears 59 c and the driving part 59 are coupled between them. However, they may also be coupled to the fifth hinge member 54 e and sixth hinge member 54 f in the same manner. Meanwhile, if the first gear 541 a is engaged with the second gear 541 b directly, the link members may be driven without an idle gear 59 c.
The functions of other components in this embodiment are similar to those of the first embodiment and will not be described in further detail herein.
The embodiment described above is for the automatic extension of the display. Here, the term “Automatic” means that the display extension unit is driven by a motor that responds to an external order signal. However, the extension may also be achieved manually, where the rotation by external forces may cause the rotor of a motor to be damaged. The structure of the driving part to prevent this damage, particularly that of the rotary part, will be described below in more detail.
FIG. 6 is a cross-sectional view of a rotary part of a driving part based on the sixth disclosed embodiment of the present invention. Referring to FIG. 6, there are shown a rotary part 60, driving shaft 61, clutch part 61 a, and driven shaft 62.
The illustrated rotary part of the driving part may be applied to any of the first through fifth embodiments. The driving shaft 61 in FIG. 6, joined to the motor unit 19 a of the driving part 10 of FIG. 1 b, serves as the rotational axis of the motor. The driving shaft 61 is coupled to the driven shaft 62 at the clutch part 61 a. The clutch part 61 a, which controls the frictional force, may be a single body as the driving shaft 61, as illustrated in FIG. 6. In addition, it may be coupled to the driven shaft 62. A washer 61 b between the clutch part 61 a and the driven shaft 62 keeps the frictional force constant.
The operation of the rotary part 60 may be described as follows: the driving forces of the motor for the link portion in the first through fifth embodiments are smaller than the frictional force of clutch part 61 b, so that there is no slipping between the clutch part 61 a and the driven shaft 62. However, in the case where external forces forcibly moves the link portion in the first through fifth embodiments to rotate the driven shaft 62, slipping does occur, because the frictional force of the clutch part 61 a is smaller than the cogging torque of the motor. Consequently, the possibility of forced rotation by external forces is deceased.
FIG. 7 a is a plan view of a display extension unit based on the seventh disclosed embodiment of the present invention. FIG. 7 b is a cross-sectional view of a pipe of a display extension unit based on the seventh disclosed embodiment of the present invention. FIG. 7 c is a cross-sectional view across the dashed section A in FIG. 7 b. Referring to FIGS. 7 a-c, there are shown a link portion 70, first link arm 700 a, second link arm 700 b, fixed body 71, movable body 72, first hinge member 73 a, second hinge member 73 b, first link member 75 a, second link member 75 b, third link member 75 c, fourth link member 75 d, fifth link member 75 e, sixth link member 75 f, screw thread 76 a, first stopping projection 76 c, second stopping projection 76 d, third stopping projection 76 e, universal joint 77, display 78, driving part 79, motor unit 79 a, driving shaft 79 b, fixing shaft 79 c, and pipe 79 d.
The main parts of the link portion 70 in the present embodiment are the first link arm 700 a and the second link arm 700 b. The first link arm 700 a includes a first hinge member 73 a, first link member 75 a, third link member 75 c, and fifth link member 75 e. Second link arm 700 b includes second hinge member 73 b, second link member 75 b, fourth link member 75 d and sixth link member 75 f.
One end and the other end of each of the first link arm 700 a and the second link arm 700 b are respectively coupled to the fixed body 71 and the movable body 72. There are a number of joining points where the link members meet, so that jointing actions are enabled. The joining between the first link arm 700 a and second link arm 700 b is described in detail as follows.
One end of each of the first link member 75 a and the second link member 75 b is hinge-joined respectively to the first and second hinge members 73 a, 73 b, to enable rotation in an arbitrary angle. In addition, there is hinge-joining between the other end of each of the first and second link members 75 a, 75 b and one end of each of the third and fourth link members 75 c, 75 d, between the other end of each of the third and fourth link members 75 c, 75 d and one end of each of the fifth and sixth link members 75 e, 75 f, and between the other end of each of the fifth and sixth link members 75 e, 75 f and the movable body 72.
Meanwhile, the driving part 79 in the present embodiment includes a motor unit 79 a, driving shaft 79 b, fixing shaft 79 c, and pipe 79 d. The motor unit 79 a is fixed to the fourth link member 75 d. The driving shaft 79 b rotates with one end coupled to the motor unit 79 a. In addition, the other end of the driving shaft 79 b is inserted to one side of the penetration hole 79 e in the pipe 79 d. One end of the fixing shaft 79 c is fixed to the third link member 75 c and the other end is inserted to the other side of the penetration hole 79 e. As illustrated in FIG. 7 b, the joining between the pipe 79 d and the driving shaft 79 b and the joining between the pipe 79 d and the fixing shaft 79 c may be screw-joining or guide-joining. That is, in the case where the pipe 79 d and the driving shaft 79 b are guide-joined, the pipe 79 d and the fixing shaft 79 c are screw-joined correspondingly.
As illustrated in FIG. 7 c, the guide-joining is a configuration that enables the driving shaft 79 b to slide in the longitudinal direction of the driving shaft 79 b into the pipe 79 d. However, guide projections 76 b are formed in the pipe 79 d to allow the pipe 79 d to rotate together with the driving shaft 79 b. Due to the slide joining between the pipe 79 d and the driving shaft 79 b, when the link portion 70 is moved manually, the difference in length between the extended and contracted states of the link portion 70 is cancelled by the sliding of the driving shaft 79 b in the penetration hole 79 e of the pipe 79 d.
Meanwhile, the pipe 79 d and the fixing shaft 79 c are screw-joined. The operation of the fixing shaft 79 c joined to the pipe 79 d, and the driving shaft 79 b is as follows. When the driving shaft 79 b is rotated to extend the link portion 70, the pipe 79 d and the driving shaft 79 b rotate together. Then, the distance between the pipe 79 d and the fixing shaft 79 c is made longer as the screw-joining is unfastened. It may be preferable to form a stopping projection 76 c to prevent the driving shaft 79 b from sliding out of the penetration hole 79 e of the pipe 79 d.
On the other hand, a second stopping projection 76 d in the penetration hole 79 e and a third stopping projection 76 e in the driving shaft 79 b prevent the driving shaft 79 b from becoming separated from the penetration hole 79 e when the fixing shaft 79 c enters the penetration hole 79 e of the pipe 79 d as the screw-joining is fastened by the rotation of the driving shaft 79 b.
While six link members are utilized in this embodiment, alternative configurations may also be used, such as with four link members hinge joined in a lozenge shape, and with the driving part 79 between the link members, as in FIG. 7 a.
According to the present invention set forth as above, rotation of the display is enabled, to separate the display from a fixed body. The separating and rotating actions can be performed automatically or manually. The durability may be increased by avoiding excessive loads on the motor even when operated manually.

Claims

1. A display extension unit comprising:

a fixed body;

a link portion having one end coupled to the fixed body;

a movable body coupled to the other end of the link portion; and

a driving part coupled to the joining point of the link portion,

wherein the driving part comprises:

a motor unit; and

a rotary part coupled to the driving shaft of the motor unit;

the rotary part comprises:

a clutch coupled to the driving shaft; and

a driven shaft positioned in contact with the clutch;

and the driving force of the motor unit is smaller than the frictional force between the driven shaft and the clutch.

2. The display extension unit of claim 1, wherein the frictional force between the driven shaft and the clutch is smaller than the cogging torque of the motor unit.

3. The display extension unit of claim 2, wherein the display extension unit further comprises one or more washers interposed between the clutch and driven shaft.

4. The display extension unit of claim 2, wherein the link portion comprises:

a first hinge member coupled to the fixed body;

a second hinge member coupled to the movable body;

a first link element having one end rotatably coupled to the first hinge member; and

a second link element having one end rotatably coupled to the second hinge member.

5. The display extension unit of claim 4, wherein the motor unit is coupled to the first hinge member or the second hinge member, and the rotary part is coupled to the first link element or the second link element, the first link element and the second link element coupled in correspondence with the first hinge member and the second hinge member, respectively.

6. The display extension unit of claim 4, wherein the link portion comprises:

a first guide member coupled to the fixed body while separated from the first hinge member; and

a second guide member coupled to the movable body while separated from the second hinge member,

and wherein the first link element and the second link element intersect,

and the other end of the first link element is coupled to be movable along the second guide element, and the other end of the second link element is coupled to be movable along the first guide element.

7. The display extension unit of claim 6, wherein the driving part is coupled to the part where the first link element and the second link element intersect, the motor unit is coupled to the first link element or the second link element, and the rotary part is coupled to that one of the first link element and the second link element to which the motor unit is not coupled.

8. The display extension unit of claim 4, wherein the link portion comprises:

a third hinge member coupled to the fixed body while separated from the first link element;

a fourth hinge member coupled to the movable body while separated from the second link element;

a third link member having one end rotatably coupled to the other end of the first link member with an interposed fifth hinge member and having the other end rotatably coupled to the fourth hinge member; and

a fourth link member having one end rotatably coupled to the other end of the second link member with an interposed sixth hinge member and having the other end rotatably coupled to the third hinge member.

9. The display extension unit of claim 8, further comprising a first gear coupled to the outer perimeter of the first hinge member, and a second gear coupled the first gear and the outer perimeter of the third hinge member.

10. The display extension unit of claim 9, wherein the first gear and the second gear are coupled by an even number of idle gears.

11. The display extension unit of claim 9, wherein the rotary part is coupled to the first gear or the second gear

12. A display extension unit comprising:

a fixed body;

a link portion comprising a first link arm and a second link arm respectively having one end coupled to the fixed body;

a movable body coupled to the other end of the first link arm or the second link arm; and

a driving part coupled to the first link arm or the second link arm,

wherein the driving part comprises:

a motor unit coupled to the first link arm or the second link arm;

a driving shaft having one end coupled to the motor unit to rotate;

a pipe having a penetration hole formed therein, the other end of the driving shaft being inserted through one side of the penetration hole; and

a fixed shaft having one end inserted through the other side of the penetration hole and having the other end coupled to the first link arm or the second link arm in correspondence with the motor unit.

13. The display extension unit of claim 12, wherein the one side of the penetration hole and the other end of the rotary shaft are coupled by guide-joining or screw-joining, and the other side of the penetration hole and the one end of the fixed shaft are coupled by guide-joining or screw-joining in correspondence with the joining of the one side of the penetration hole and the other end of the rotary shaft