Patent Publication Number: US-2023148758-A1

Title: Chair including multi-channel sound system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on the PCT Application No. PCT/KR2021/011071, filed on Aug. 20, 2021, and claims the benefit of priority from the prior Korean Patent Application No. 10-2020-0105177, filed on Aug. 21, 2020 and the prior Korean Patent Application No. 10-2020-0111831, filed on Sep. 2, 2020, the disclosures of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to a chair including a multi-channel sound system, and more particularly, to a chair including a multi-channel sound system capable of providing a sense of space and a three-dimensional effect to a user who sits in the chair through sounds output from a plurality of channels. 
     2. Discussion of Related Art 
     In general, a speaker used while being connected to a computer generates sound by converting a current flowing through a wire into an electrical signal and a vibration signal and generating vibrations using a vibration portion. 
     For example, when watching a movie or playing a game using a computer, a user not only watches images on a screen of the computer but also listens to sounds due to an electrical signal being transferred and vibrations generated by a speaker corresponding to the images being transferred to ears of the user while the user sits in a chair where a monitor of the computer is seen. 
     Particularly, a multi-channel sound system including a plurality of such speakers has an advantage of allowing a user to more exquisitely experience a direction, level, and the like of a sound in an image. 
     However, in order to implement such multi-channel sound systems, it is necessary to provide a plurality of speakers above and below a desk, behind a chair, and the like and to electrically connect all of the plurality of speakers such that there is a great restriction in space. 
     Also, although a multi-channel sound system is implemented by arranging the plurality of speakers, there is a problem that a position of the chair is changed or a variety of physical interferences are present between the speakers and the user who sits in the chair. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to providing a chair including at least 1) a backrest portion configured to support a back and waist part of a user and 2) a seat portion configured to support a buttocks part and a part of legs of the user, the chair including at least one main frame extending a predetermined length toward a front from the backrest portion, wherein a multi-channel sound system is implemented as a first speaker installation area in which at least one speaker is installed is defined in a direction in which the main frame extends. 
     The objectives of the present invention are not limited to the above-mentioned objectives, and other unmentioned objectives and advantages of the present invention should be understood from the description below and should be more clearly understood from embodiments of the present invention. Also, those of ordinary skill in the art should easily understand that the objectives and advantages of the present invention may be realized by means shown in the claims below and combinations thereof. 
     According to one aspect of the present invention, there is provided a chair including at least 1) a headrest portion configured to support a head part of a user, 2) a backrest portion configured to support a back and waist part of the user, 3) a seat portion configured to support a buttocks part and a part of legs of the user, and 4) side support portions configured to support sides of the user, the chair including at least one main frame which is installed in an arbitrary area of the chair and has a shape that passes by a side of the user sitting in the chair and extends toward a front of the user, wherein a first speaker installation area in which at least one speaker is installed is defined in a direction in which the main frame extends. 
     In one embodiment, a main frame rotating shaft may be provided inside or behind the headrest portion, the backrest portion, or the seat portion, and the main frame may be provided to be connected to the main frame rotating shaft to be rotatable within a predetermined angle range in an axial direction of the main frame rotating shaft. 
     In another embodiment, an installation frame having a shape that extends in a vertical direction may be provided inside or behind the headrest portion, the backrest portion, or the seat portion, and the main frame may be provided to be connected to the installation frame to be able to move upward or downward in a direction in which the installation frame extends. 
     In still another embodiment, the main frame may be installed on at least one selected from the backrest portion, the seat portion, and the side support portions, at least one head frame having a shape that passes by a portion above a user sitting in the chair and extends toward a front of the user may be installed on the headrest portion, and a second speaker installation area in which at least one speaker is installed may be defined in a direction in which the head frame extends. 
     In yet another embodiment, an installation frame having a shape that extends in a vertical direction may be provided on the side support portions, the main frame may be installed on the installation frame with a main frame rotating shaft as a medium, and the main frame may be provided to be connected to the main frame rotating shaft to be rotatable within a predetermined angle range in an axial direction of the main frame rotating shaft. 
     According to the present invention, there is an advantage that a user can experience vivid sounds like those existing in actually reproduced images or game environments just by sitting in a chair. 
     In particular, since it is possible to transfer generated sounds to the user while the sounds are separated in a variety of directions such as frontward, rearward, sideward, upward, downward directions, and the like in reproduced images or game environments according to positions and the number of speakers provided in the chair, a true multi-channel sound system can be implemented. 
     Specific advantageous effects of the present invention, in addition to the advantageous effects described above, will be described below in the description of details for carrying out the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a front view of a chair according to one embodiment of the present invention. 
         FIG.  2    is a front view of a chair according to another embodiment of the present invention. 
         FIG.  3    is a lateral view of a chair according to still another embodiment of the present invention. 
         FIGS.  4  and  5    are top views of the chair illustrated in  FIG.  3   . 
         FIG.  6    is a perspective view illustrating one portion of a main frame applied to the chair according to one embodiment of the present invention. 
         FIGS.  7 A and  7 B  are front views illustrating the portion of the main frame applied to the chair according to one embodiment of the present invention. 
         FIG.  8    is a top view of a chair according to yet another embodiment of the present invention. 
         FIG.  9    is a front view of the chair according to yet another embodiment of the present invention. 
         FIG.  10    is a lateral view of the chair according to yet another embodiment of the present invention. 
         FIG.  11    is a front view of a chair according to yet another embodiment of the present invention. 
         FIG.  12    is a front view of a chair according to yet another embodiment of the present invention. 
         FIG.  13    is a front view of a chair according to yet another embodiment of the present invention. 
         FIG.  14    is a top view of a chair according to yet another embodiment of the present invention. 
         FIG.  15    is a top view of a chair according to yet another embodiment of the present invention. 
         FIG.  16    is a lateral view of a chair according to yet another embodiment of the present invention. 
         FIG.  17    is a lateral view of a chair according to yet another embodiment of the present invention. 
         FIG.  18    is a top view of a chair according to yet another embodiment of the present invention. 
         FIG.  19    is a lateral view of the chair illustrated in  FIG.  18   . 
         FIG.  20    is a top view of a chair according to yet another embodiment of the present invention. 
         FIG.  21    is a lateral view of the chair illustrated in  FIG.  20   . 
         FIG.  22    is a perspective view illustrating one portion of a head frame applied to the chair illustrated in  FIG.  20   . 
         FIGS.  23 A to  23 C  are front views illustrating one portion of the head frame applied to the chair illustrated in  FIG.  20   . 
         FIG.  24    is a top view of a chair according to yet another embodiment of the present invention. 
         FIGS.  25  and  26    are perspective views illustrating one portion of a head frame applied to the chair illustrated in  FIG.  24   . 
         FIGS.  27  and  28    illustrate modified examples of the head frame applied to the chair illustrated in  FIG.  24   . 
         FIG.  29    is a top view of a chair according to yet another embodiment of the present invention. 
         FIG.  30    is a lateral view of the chair illustrated in  FIG.  29   . 
         FIG.  31    is a lateral view of a chair according to yet another embodiment of the present invention. 
         FIG.  32    is a lateral view of a chair according to yet another embodiment of the present invention. 
         FIG.  33    is a front view of a chair according to yet another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, a chair including a multi-channel sound system according to some embodiments of the present invention will be described in detail with reference to the accompanying drawings. Also, each piece of content relating to the chair according to some embodiments of the present invention described with reference to the accompanying drawings should be understood as an independent embodiment, and at least two independent embodiments may be combined when necessary. 
     Meanwhile, components of a previously-described embodiment or an embodiment to be described may be referenced for components insufficiently described through the accompanying drawings. 
       FIG.  1    is a front view of a chair according to one embodiment of the present invention,  FIG.  2    is a front view of a chair according to another embodiment of the present invention,  FIG.  3    is a lateral view of a chair according to still another embodiment of the present invention, and  FIGS.  4  and  5    are top views of the chair illustrated in  FIG.  3   . 
     Referring to  FIGS.  1  to  5   , a chair  100  includes at least 1) a headrest portion H configured to support a head part of a user who sits in the chair  100 , 2) a backrest portion B configured to support a back and waist part of the user, 3) a seat portion S configured to support a buttocks part and a part of legs of the user, and 4) side support portions A configured to support sides of the user. 
     Although the chair  100  is illustrated as a movable chair, in which a movable member BT is provided below the seat portion S, in the accompanying drawings, the present invention is not necessarily limited thereto, and the chair  100  may also be provided in the form of an immovable chair, e.g., sofa. 
     The headrest portion H installed above the backrest portion B may be configured to be detachable from the backrest portion B or integrally formed with the backrest portion B as necessary. 
     For comfort of the user who sits in the chair  100 , the headrest portion H, the backrest portion B, and/or the seat portion S may be provided in the form in which a front or inside (that is, a part which comes into contact with the back, waist, and side parts of the user) is formed of a cushioning material or has a cushioning material added thereon. 
     Also, a woofer speaker WS may be additionally provided on the backrest portion B and/or the seat portion S. In a case in which the woofer speaker WS is provided on the backrest portion B and/or the seat portion S, since vibrations generated by the woofer speaker WS can be directly transferred to the user who sits in the chair  100 , a more vivid user experience can be provided. The woofer speaker WS provided on the inside of the backrest portion B and/or the seat portion S may be installed as many as the number necessary to implement the multi-channel sound system. The woofer speaker WS may be installed in at least one area selected from a front surface, a rear surface, a side surface, and the inside of the backrest portion B and/or the seat portion S. 
     Although not separately illustrated in the drawings, for comfort of the user who sits in the chair  100 , at least one selected from a warmer, a ventilator, and a massager may be provided on the backrest portion B and/or the seat portion S. 
     Meanwhile, a vibration dampening member OS may be selectively provided between the seat portion S and the movable member BT. The vibration dampening member OS serves to prevent or reduce transmission of vibrations, generated from a plurality of speakers disposed above the seat portion S, to a portion below the chair  100 . The vibration dampening member OS is provided as a material which can adsorb vibrations, such as a spring, cushion, or foam. 
     At least one main frame  110  having a shape that passes by a side of the user sitting in the chair  100  and extends toward a front of the user is installed in an arbitrary area of the chair  100 . 
     Here, the arbitrary area of the chair  100  in which the main frame  110  is installed refers to the headrest portion H, the backrest portion B, the seat portion S, and/or the side support portions A that constitute the chair  100 . 
     Hereinafter, first, an embodiment in which the main frame  110  is installed on the backrest portion B will be described. 
     At least one main frame  110  extending a predetermined length toward a front may be installed on the backrest portion B, and a first speaker installation area SA in which at least one speaker  120  is installed may be defined in a direction in which the main frame  110  extends. Here, the direction toward the front is a direction toward the front of the user who sits in the chair  100  and refers to a direction toward arbitrary positions placed relatively in front of at least both sides of the user who sits in the chair  100 . That is, in this case, one end portion of the main frame  110  that is not fixed to the chair  100  may be positioned in a field of vision in front of the user who sits in the chair  100 . In this way, since the main frame  110  has a shape that surrounds the user sitting in the chair  100  while spaced a predetermined distance apart from the user, it is possible to implement an effect that sounds implemented by the at least one speaker  120  installed in the main frame  110  are generated from an arbitrary space surrounding the user. 
     For example, referring to  FIG.  1   , the main frame  110  may be installed inside or behind the backrest portion B, the first speaker installation area SA may be defined in the direction in which the main frame  110  extends, and at least one speaker  120 , which may be a plurality of speakers  120 , may be installed in the first speaker installation area SA. 
     In a case in which the main frame  110  is installed inside the backrest portion B, the main frame  110  may have a shape that protrudes in at least one of both side directions of the backrest portion B and extends a predetermined length toward a front of the chair  100 . 
     Meanwhile, in a case in which the main frame  110  is installed behind the backrest portion B, a separate support member configured to fix the main frame  110  and the backrest portion B may be interposed to withstand a load of the main frame  110 . In this case, the main frame  110  may have a shape that is installed on the separate support member and extends a predetermined length from behind the backrest portion B toward the front of the chair  100 . 
     The main frame  110  installed on the backrest portion B may be installed as many as the number necessary to implement the multi-channel sound system. For example, as illustrated in  FIG.  2   , two main frames  110  may be installed inside or behind the backrest portion B. 
     Meanwhile, the speaker  120  may be integrally provided with the main frame  110  or provided to be detachable from the main frame  110 . Also, in another modified example, the main frame  110  may be configured by connecting a plurality of speakers  120  to each other. 
     Here, the speakers  120  may be speakers in the form of a complete product, speaker units connected to driving portions separately provided at the first speaker installation areas SA and configured to operate as a complete product, display type speakers, thin-film type speakers, or one-way and multi-way speakers, and the speakers  120  may operate by receiving sound signals through wires or wirelessly. The description of the speakers  120  may be equally applied to speakers provided in a second speaker installation area which will be described below. 
     Meanwhile, although not separately illustrated in the drawings, in a case in which the speakers receive sounds wirelessly, the chair  100  may include a wireless reception portion. The wireless reception portion may wirelessly transmit or receive sound signals to or from a sound source (for example, home theater, TV, set-top box, sound bar, computer, cellular phone, tablet PC, or the like) using a method such as Wi-Fi, Bluetooth, digital enhanced cordless telecommunications (DECT), Li-Fi, and the like. The wireless reception portion may be provided in a binding portion and/or a connecting portion which will be described below. Meanwhile, the wireless reception portion may be installed in an arbitrary area of the chair  100 . 
     Also, the speakers  120  may be directly installed in the first speaker installation areas SA, but the present invention is not necessarily limited thereto, and an accessory for installing a speaker may be separately provided between the first speaker installation areas SA and the speaker  120 . 
     Meanwhile, the main frame  110  may have a linear shape that extends a predetermined length from the backrest portion B toward the front of the chair  100  (or toward the front of the user sitting in the chair  100  after passing by a side of the user). Also, the main frame  110  may have a nonlinear shape, e.g., various shapes such as a broken-line shape or a curved shape, as necessary. In this case, the main frame  110  may have a form that surrounds the user who sits in the chair  100 . Accordingly, in a case in which a plurality of speakers  120  are installed in the main frame  110 , it is possible to maintain a constant distance between the plurality of speakers  120  and the user. Also, in a case in which a plurality of speakers  120  with different performance are installed in the main frame  110 , it may be possible to adjust a distance between each speaker  120  and the user in consideration of the performance of the speakers  120 . 
     The shape of the main frame  110  may be equally applied to an installation frame, a first main frame, a second main frame, a first sub-frame, a head frame, and a second sub-frame which will be described below, as long as the scope does not deviate from the scope of the present invention. 
     Referring to  FIGS.  3  and  4   , a main frame rotating shaft  113  may be positioned inside or behind the backrest portion B, and the main frame  110  may be provided to be connected to the main frame rotating shaft  113  to be rotatable within a predetermined angle range in an axial direction of the main frame rotating shaft  113 . 
     For example, the main frame  110  may be connected to the main frame rotating shaft  113  and rotate on a vertical or horizontal plane. Here, the vertical plane refers to a plane which is vertically orthogonal to an arbitrary horizontal plane parallel to the ground, and the horizontal plane refers to a plane which is parallel to the ground or parallel to an arbitrary horizontal plane parallel to the ground. 
     Although not separately illustrated in the drawings, according to another modified example of the present invention, the main frame rotating shaft  113  may be provided on both sides of the backrest portion B, and accordingly, two main frames  110  may be individually connected to the main frame rotating shafts  113  each provided on both sides of the backrest portion B and may extend toward the front of the chair  100 . 
     In still another embodiment of the present invention, an installation frame  111  extending in the vertical direction may be positioned inside or behind the backrest portion B, and the main frame  110  may be installed on the installation frame  111 . 
     In a case in which the backrest portion B has a shape bent at a predetermined angle or is bendable, the installation frame  111  may be positioned while spaced apart from the backrest portion B at a predetermined interval in order to maintain an angle of orientation of the main frame  110 . 
     Here, the main frame  110  may be positioned to be parallel to a plane vertical to the ground while spaced apart from the backrest portion B at a predetermined interval, but the present invention is not necessarily limited thereto, and the main frame  110  may be provided to be inclined at a predetermined angle with respect the plane vertical to the ground. 
     To this end, at least one interval adjustment member  112  may be positioned between the backrest portion B and the installation frame  111 . The interval adjustment member  112  serves to simultaneously adjust an interval between the backrest portion B and the installation frame  111  and adjust an angle of the installation frame  111  with respect to the backrest portion B. 
     Also, the main frame  110  may be installed on the installation frame  111  with the main frame rotating shaft  113  as a medium. In this case, the main frame rotating shaft  113  may be provided to be able to move upward or downward in a direction in which the installation frame  111  extends, and as a result, the main frame  110  connected to the main frame rotating shaft  113  may, along with the main frame rotating shaft  113 , move upward or downward in the direction in which the installation frame  111  extends. 
     Here, the main frame  110  may be detachable from the main frame rotating shaft  113 , or the main frame rotating shaft  113  may be provided to be detachable from the installation frame  111  in a state in which the main frame  110  is connected to the main frame rotating shaft  113 . 
     Here, in a case in which the installation frame  111  is positioned inside or behind the backrest portion B, the installation frame  111  and the backrest portion B may be integrally formed. Also, when necessary, the installation frame  111  may be provided to be detachable from the backrest portion B. 
     Meanwhile, the main frame  110  may be provided as a single member, but as illustrated in  FIG.  4   , main frames  110   a  and  110   b  positioned at a left side and a right side of the chair  100  may be provided as separate members. 
     In this case, the main frame  110  may pass through the center of the chair  100  and may include at least one first main frame  110   a  which is positioned at the left side with respect to a virtual reference line VL 1 -VL 1 ′ connecting the front and rear of the chair  100 , that is, has a shape that passes by the left side of the user sitting in the chair  100  and extends toward the front of the user, and at least one second main frame  110   b  which is positioned at the right side with respect to the virtual reference line VL 1 -VL 1 ′, that is, has a shape that passes by the right side of the user sitting in the chair  100  and extends toward the front of the user. 
     Referring to  FIG.  5   , the speakers  120  installed in the first main frame  110   a  and/or the second main frame  110   b  may be provided to be able to insert or withdraw in a direction oriented toward the user who sits in the chair  100 . As described above, in a case in which a plurality of speakers  120  with different performance are installed in the first main frame  110   a  and/or the second main frame  110   b,  when it is necessary to adjust a distance between each speaker  120  and the user in consideration of the performance of the speakers  120 , inserting or withdrawing the speakers  120  into or from the first main frame  110   a  and/or the second main frame  110   b  may be useful. 
     Here, an insertable/withdrawable protruding member  121  may be provided to allow the speakers  120  to protrude from the first speaker installation area SA defined in the first main frame  110   a  and/or the second main frame  110   b.    
       FIG.  6    is a perspective view illustrating one portion of a main frame applied to the chair according to one embodiment of the present invention, and  FIG.  7    is a front view illustrating the portion of the main frame applied to the chair according to one embodiment of the present invention. Although  FIGS.  6  and  7   , for convenience, illustrate only the second main frame  110   b,  the content to be described with reference to  FIGS.  6  and  7    is applicable equally to the first main frame and the first sub-frame, the head frame, and the second sub-frame which will be described below. 
     Referring to  FIGS.  6  and  7   , at least one speaker  120  installed in the second main frame  110   b  may be installed to be able to slide in a direction in which the second main frame  110   b  extends. Accordingly, there is an advantage that each user may be allowed to customize a sound system for himself or herself by adjusting a position of the at least one speaker  120  installed in the second main frame  110   b.    
     Specifically, a sliding space  115  having a shape that is bent in the direction in which the second main frame  110   b  extends may be formed on an inner side surface  110   b - a  of the second main frame  110   b.  The at least one speaker  120  may be installed in the sliding space  115 . The sliding space  115  may be formed to pass through the second main frame  110   b  but may also be formed while an outer side surface of the second main frame  110   b  is blocked. 
     Referring to  FIG.  7 A , a sliding rail  116  may be selectively provided above and/or below the sliding space  115 . A sliding member  117  provided above and/or below the speaker  120  installed in the sliding space  115  is installed to be able to slide on the sliding rail  116 . The speaker  120  may slide in the direction in which the second main frame  110   b  extends while being stably supported by the sliding rail  116  and additionally in the sliding space  115  by the sliding member  117 . 
     Meanwhile, referring to  FIG.  7 B , the sliding member  117  may be provided as a rotatable member so that the speaker  120  supported by the sliding rail  116  is rotatable in an axial direction. 
     Accordingly, the at least one speaker  120  installed in the second main frame  110   b  is, while being slidable in the direction in which the second main frame  110   b  extends, rotatable in the axial direction so as to implement more diverse sound environments. 
       FIG.  8    is a top view illustrating a rotating operation of a main frame applied to a chair according to yet another embodiment of the present invention. The first main frame  110   a  and/or the second main frame  110   b  may be provided to be connected to main frame rotating shafts  113   a  and  113   b,  respectively, to be independently rotatable within a predetermined angle range on a plane vertical or horizontal to the ground. 
     For example, the first main frame  110   a  and/or the second main frame  110   b  may be connected to the main frame rotating shafts  113   a  and  113   b,  respectively, to be tilted in an arbitrary direction (e.g., forward, rearward, upward, or downward). 
       FIGS.  9  and  10    illustrate a lifting/lowering operation of the main frame applied to the chair according to yet another embodiment of the present invention. The main frame  110  connected to the main frame rotating shaft  113  may, along with the main frame rotating shaft  113 , move upward or downward in the direction in which the installation frame  111  extends. 
     A range in which the lifting/lowering operation of the main frame  110  occurs may be at least between the headrest portion H and the seat portion S, and when the main frame  110  moves upward to a position near the headrest portion H, positions at which sounds are generated from the speakers  120  provided in the main frame  110  may be at least in the vicinity of an ear of the user who sits in the chair  100 . 
       FIG.  11    is a front view of a chair according to yet another embodiment of the present invention. 
     Referring to  FIG.  11   , the main frame  110  may be provided as a single member provided in a state of being connected to the above-described main frame rotating shaft  113  and may be provided to be rotatable within a predetermined angle range on a plane vertical to the ground. Here, in a case in which one end portion of the main frame  110  that is positioned at the left side of the chair  100  moves downward due to rotation, the other end portion of the main frame  10  that is positioned at the right side of the chair  100  moves upward due to rotation. 
       FIG.  12    is a front view of a chair according to yet another embodiment of the present invention. 
     Referring to  FIG.  12   , the main frame  110  may be provided as two members, and here, the main frame  110  may include the first main frame  110   a  and the second main frame  110   b.  The first main frame  110   a  and the second main frame  110   b  may be individually connected to the above-described main frame rotating shafts  113   a  and  113   b,  respectively. 
     Accordingly, the first main frame  110   a  and the second main frame  110   b  may be provided to be independently rotatable within a predetermined angle range on a vertical plane. 
       FIG.  13    is a front view of a chair according to yet another embodiment of the present invention. 
     Referring to  FIG.  13   , the main frame  110  may be provided as two or four members. In a case in which the main frame  110  is provided as two members, the main frame  110  may include the first main frame  110   a  or  110   a ′ and the second main frame  110   b  or  110   b ′. The first main frame  110   a  or  110   a ′ and the second main frame  110   b  or  110   b ′ may each be individually connected to the main frame rotating shafts. 
     Accordingly, the first main frame  110   a  or  110   a ′ and the second main frame  110   b  or  110   b ′ may be provided to be independently rotatable within a predetermined angle range on a vertical plane. 
     Meanwhile, as the first main frame  110   a  or  110   a ′ and the second main frame  110   b  or  110   b ′ are each divided into two main frames, the main frame  110  may be provided as a total of four members, and the four members may each be provided to be individually connected to the main frame rotating shafts to be independently rotatable within a predetermined angle range on a vertical plane. 
       FIG.  14    is a top view of a chair according to yet another embodiment of the present invention. 
     Referring to  FIG.  14   , the main frame  110 , for example, the first main frame  110   a  and the second main frame  110   b,  may include a plurality of fragments connected with at least one joint member  114  as a medium in directions in which the first main frame  110   a  and the second main frame  110   b  extend. Here, each fragment may be a unit including at least one speaker  120 . 
     The joint member  114  allows the plurality of fragments connected with the joint member  114  as a medium to be freely tilted in any direction. By allowing the plurality of fragments constituting the first main frame  110   a  and the second main frame  110   b  to be freely tilted in any direction by a user when necessary, it is possible to implement a sound environment optimized for the user. 
       FIG.  15    is a top view of a chair according to yet another embodiment of the present invention. 
     Referring to  FIG.  15   , the first main frame  110   a  and the second main frame  110   b  may be provided so that lengths at which the first main frame  110   a  and the second main frame  110   b  extend forward are adjustable from the backrest portion B or the main frame rotating shafts  113   a  and  113   b.  Here, the first main frame  110   a  and the second main frame  110   b  may have an end structure in which one end portion is able to be inserted or withdrawn in a multi-stage manner. 
       FIG.  16    is a lateral view of a chair according to yet another embodiment of the present invention. 
     Referring to  FIG.  16   , at least one first sub-frame  130  may be disposed in a direction in which the main frame  110  (here, the main frame  110  includes the first main frame  110   a  and the second main frame  110   b ) extends. The first sub-frame  130  may have a shape that extends a predetermined length in a direction intersecting (preferably, vertically intersecting) the direction in which the main frame  110  extends. 
     In a case in which the first sub-frame  130  is disposed on the main frame  110 , the first speaker installation area SA may be defined in at least one frame selected from the main frame  110  and the first sub-frame  130 . That is, the first speaker installation area SA may be defined in both the main frame  110  and the first sub-frame  130 , or the first speaker installation area SA may be defined in only the first sub-frame  130 . In a case in which the first speaker installation area SA is defined in both the main frame  110  and the first sub-frame  130 , a speaker installed in the speaker installation area defined in the main frame  110  and a speaker installed in the speaker installation area defined in the first sub-frame  130  may be provided at positions not overlapping each other. 
     Also, the first sub-frame  130  may be installed in arbitrary areas of the first main frame  110   a  and the second main frame  110   b  with a first sub-frame rotating shaft  131  as a medium, and here, the first sub-frame  130  may be provided to be connected to the first sub-frame rotating shaft  131  to be rotatable within a predetermined angle range on a vertical plane. 
     Meanwhile, referring to  FIG.  17    which is a lateral view of a chair according to yet another embodiment of the present invention, similarly to the chair illustrated in  FIG.  16   , a plurality of first sub-frames  130   a  and  130   b  may be disposed in the direction in which the main frame  110  (here, the main frame  110  includes the first main frame  110   a  and the second main frame  110   b ) extends. Here, the plurality of first sub-frames  130   a  and  130   b  may have different shapes and/or extension lengths. 
     Meanwhile, according to one embodiment of the present invention, the main frame  110  may be, instead of being installed on the headrest portion H of the chair  100 , installed on the backrest portion B, the seat portion S, and/or the side support portions A. 
     Here, at least one head frame  140  having a shape that passes by a portion above the user sitting in the chair  100  and extends toward the front of the user may be installed on the main frame  110 , the backrest portion B, or the headrest portion H. 
     Also, in a case in which the main frame  110  is installed on the installation frame  111 , a first head frame  140  may also be installed on the installation frame  111  and have a shape that passes by a portion above the user sitting in the chair  100  and extends toward the front of the user. 
       FIG.  18    is a top view of a chair according to yet another embodiment of the present invention, and  FIG.  19    is a lateral view of the chair illustrated in  FIG.  18   . 
     Referring to  FIGS.  18  and  19   , at least one first head frame  140  that passes by a portion above the user sitting in the chair  100  and extends a predetermined length toward the front of the user is installed on the headrest portion H configured to support the head part of the user sitting in the chair  100 . 
     Likewise, the second speaker installation area in which at least one speaker is installed may be defined in a direction in which the head frame  140  extends. 
     On the other hand, referring to  FIGS.  20  and  21    illustrating a chair according to yet another embodiment of the present invention and  FIG.  22    illustrating one portion of a head frame applied to the chair illustrated in  FIG.  20   , second and third head frames  150  include a second head frame  151  which is provided to extend in one direction of the headrest portion H and has at least one speaker  120  installed on an inner side  151   a  thereof and a third head frame  152  which is provided to extend in the other direction of the headrest portion H and has at least one speaker  120  installed on an inner side  152   a  thereof. 
     The second head frame  151  having a shape that extends in the one direction of the headrest portion H is provided on one side of the headrest portion H. At least one speaker  120  may be installed at the front or on the inner side  151   a  of the second head frame  151 . 
     In a case in which at least two speakers  120  are installed on the inner side  151   a  of the second head frame  151 , the two speakers  120  may be installed to be spaced apart from each other at a predetermined interval from one end  151   b  of the second head frame  151  fixed to the headrest portion H toward one end  151   c  of the second head frame  151  not fixed to the headrest portion H. 
     Likewise, the third head frame  152  having a shape that extends in the other direction of the headrest portion H is provided on the other side of the headrest portion H. At least one speaker  120  may be installed at the front or on the inner side  152   a  of the third head frame  152 . 
     In a case in which at least two speakers  120  are installed on the inner side  152   a  of the third head frame  152 , the two speakers  120  may be installed to be spaced apart from each other at a predetermined interval from one end  152   b  of the third head frame  152  fixed to the headrest portion H toward the other end  152   c  of the third head frame  152  not fixed to the headrest portion H. 
     In one embodiment, the one end  151   b  of the second head frame  151  and the one end  152   b  of the third head frame  152  may be installed to be fixed to both sides of the headrest portion H, and the one end  151   c  of the second head frame  151  and the other end  152   c  of the third head frame  152 , which are not fixed to the headrest portion H, may be provided to be inclined toward the front or inside of the headrest portion H. 
     In this way, by being provided to be inclined toward the front or inside of the headrest portion H, the one end  151   c  of the second head frame  151  and the other end  152   c  of the third head frame  152 , which are not fixed to the headrest portion H, may allow sounds output from a plurality of speakers  120  installed in the second head frame  151  and the third head frame  152  to be further concentrated on the user. 
     Also, as the one end  151   c  of the second head frame  151  and the other end  152   c  of the third head frame  152 , which are not fixed to the headrest portion H, are provided to be inclined toward the front or inside of the headrest portion H, it is possible to maintain a constant distance between the plurality of speakers  120  and the user who sits in the chair in which the second and third head frames  150  are installed. 
     The second head frame  151  and the third head frame  152  may have a shape that is bent or curved from the headrest portion H toward the front of the chair or may have a linear shape or an angular shape which has at least one joint structure in the middle. 
     Here, the one end  151   c  of the second head frame  151  and the other end  152   c  of the third head frame  152 , which are not fixed to the headrest portion H, may be arranged to be inclined from the headrest portion H toward the front of the chair. 
     As described above, by the second head frame  151  and the third head frame  152  installed to extend from both sides of the headrest portion H and the plurality of speakers  120  installed in the second head frame  151  and the third head frame  152 , a multi-channel sound system may be implemented by receiving and outputting a multi-channel sound signal from a separately-provided sound source (e.g., home theater, TV, set-top box, sound bar, computer, cellular phone, tablet PC, or the like). 
     Also, the second head frame  151  and the third head frame  152  may be integrally configured. 
       FIGS.  23 A to  23 C  illustrate one portion of the head frame applied to the chair illustrated in  FIG.  20    and schematically illustrates an operation of a speaker installed in the head frame. 
     Referring to  FIGS.  23 A to  23 C , the one end  151   b  of the second head frame  151  and the one end  152   b  of the third head frame  152  may be installed to be rotatable about a joint of the headrest portion H. 
     Specifically, the second head frame  151  and the third head frame  152  are rotatable in the extending directions thereof (see  FIGS.  23 A and  23 B ). 
     Also, here, joint portions  157  may allow the second head frame  151  and the third head frame  152  to be freely bendable with respect to the headrest portion H (see  FIG.  23 C ). 
     Accordingly, when a user sits in the chair in which the second and third head frames  150  are installed or stands up from the chair, the directions and positions of the second head frame  151  and the third head frame  152  may be adjusted so as not to interfere with the user. In another case, the directions of the second head frame  151  and the third head frame  152  may be adjusted through manual adjustment by the user or automatic adjustment by a separate algorithm, and in this way, it may be possible to further optimize the directions in a state in which the user sits in the chair and to create a sound environment customized for the user. 
       FIG.  24    is a top view of a chair according to yet another embodiment of the present invention, and  FIGS.  25  and  26    are perspective views illustrating one portion of a head frame applied to the chair illustrated in  FIG.  24   . 
     Referring to  FIGS.  24  to  26   , the second head frame  151  and the third head frame  152  are provided to extend from both sides of the headrest portion H, and above the headrest portion H, a first head frame  140  which is provided to extend in a direction toward a portion above the headrest portion H and which has a first speaker installation area in which at least one speaker  120  is installed defined on an inner side  140   a  may be installed. 
     Here, a sound input device M may be provided in at least one selected from the second head frame  151  and the third head frame  152 . Meanwhile, although not separately illustrated in the drawings, the sound input device M may also be provided in the main frame  110 . 
     In the present embodiment, the first head frame  140  having a shape that extends toward the front of the headrest portion H is provided above the headrest portion H. Instead of being installed above the headrest portion H, the first head frame  140  may be installed on a front surface, a rear surface, or an inside of the headrest portion H. 
     At least one speaker  120  may be installed on the inner side  140   a  of the first head frame  140 . In a case in which at least two speakers  120  are installed on the inner side  140   a  of the first head frame  140 , the two speakers  120  may be installed to be spaced apart from each other at a predetermined interval from one end  140   b  of the first head frame  140  fixed to the headrest portion H toward the other end  140   c  of the first head frame  140  not fixed to the headrest portion H. 
     In one embodiment, the one end  140   b  of the first head frame  140  may be installed to be fixed to an upper portion of the headrest portion H, and the other end  140   c  of the first head frame  140  not fixed to the headrest portion H may have a shape that is bent or curved toward the front of the headrest portion H or may have a linear shape or an angular shape which has at least one joint structure in the middle. 
     In this way, by being provided to be inclined toward the front of the headrest portion H, the other end  140   c  of the first head frame  140  not fixed to the headrest portion H may allow sounds output from the at least one speaker  120  installed in the first head frame  140  to be further concentrated on the user. 
     Also, in a case in which the speaker  120  installed in the first head frame  140  is provided as a plurality of speakers  120 , as the other end  140   c  of the first head frame  140  not fixed to the headrest portion H is provided to be inclined toward the front of the headrest portion H, it is possible to maintain a constant distance between the plurality of speakers  120  installed in the first head frame  140  and the user who sits in the chair. In particular, in this case, a constant distance can be maintained not only between the speakers  120  installed in the first head frame  140  and the user but also between the plurality of speakers  120  installed in the second head frame  151  and the third head frame  152  and the user. 
     As described above, by the first head frame  140  installed to extend to a portion above the headrest portion H and the at least one speaker  120  installed in the first head frame  140 , a multi-channel sound system may be implemented by receiving and outputting a multi-channel sound signal from a separately-provided sound source (e.g., home theater, TV, set-top box, sound bar, computer, cellular phone, tablet PC, or the like). 
     Also, the second head frame  151  and the third head frame  152  may be integrally configured, and here, the first head frame  140 , the second head frame  151 , and the third head frame  152  may be integrally configured. 
     In yet another embodiment, the one end  140   b  of the first head frame  140  may be installed to be hinge-rotatable about the headrest portion H with a hinge portion  142  as a medium. 
     In this case, when a user sits in the chair in which the first head frame  140  is installed or stands up from the chair, the direction of the first head frame  140  may be adjusted so as not to interfere with the user. In another case, the direction of the first head frame  140  may be adjusted through manual adjustment by the user or automatic adjustment by a separate algorithm, and in this way, it may be possible to further optimize the direction in a state in which the user sits in the chair and to create a sound environment customized for the user. 
       FIG.  27    illustrates a modified example of the head frame applied to the chair illustrated in  FIG.  24   . 
     Referring to  FIG.  27   , at least one fourth head frame  145  may be installed in at least one area selected from an area between the second head frame  151  and the first head frame  140  and an area between the third head frame  152  and the first head frame  140 . 
     In the present embodiment, the fourth head frame  145  having a shape that extends toward the front of the headrest portion H is provided in at least one area selected from the area between the second head frame  151  and the first head frame  140  and the area between the third head frame  152  and the first head frame  140 . At least one speaker  120  may be installed on an inner side  145   a  of the fourth head frame  145 . 
     In a case in which at least two speakers  120  are installed on the inner side  145   a  of the fourth head frame  145 , the two speakers  120  may be installed to be spaced apart from each other at a predetermined interval from one end of the fourth head frame  145  fixed to the headrest portion H toward the other end of the fourth head frame  145  not fixed to the headrest portion H. 
     In one embodiment, the one end of the fourth head frame  145  may be installed to be fixed to the headrest portion H, and the other end of the fourth head frame  145  not fixed to the headrest portion H may have a shape that is bent or curved toward the front of the headrest portion H or may have a linear shape or an angular shape which has at least one joint structure in the middle. 
     In this way, by being provided to be inclined toward the front of the headrest portion H, the other end of the fourth head frame  145  not fixed to the headrest portion H may allow sounds output from the at least one speaker  120  installed in the fourth head frame  145  to be further concentrated on the user. 
     Also, in a case in which the speaker  120  installed in the fourth head frame  145  is provided as a plurality of speakers  120 , as the other end of the fourth head frame  145  not fixed to the headrest portion H is provided to be inclined toward the front of the headrest portion H, it is possible to maintain a constant distance between the plurality of speakers  120  installed in the fourth head frame  145  and the user who sits in the chair. In particular, in this case, a constant distance can be maintained not only between the speakers  120  installed in the fourth head frame  145  and the user but also between the plurality of speakers  120  installed in the second head frame  151 , the third head frame  152  and the first head frame  140  and the user. 
     As described above, by the fourth head frame  145  installed to extend to a portion above the headrest portion H and the at least one speaker  120  installed in the fourth head frame  145 , a multi-channel sound system may be implemented by receiving and outputting a multi-channel sound signal from a separately-provided sound source (e.g., home theater, TV, set-top box, sound bar, computer, cellular phone, tablet PC, or the like). 
     In yet another embodiment, the one end of the fourth head frame  145  may be installed to be hinge-rotatable about the headrest portion H like the one end  140   b  of the first head frame  140 . 
     In this case, when a user sits in the chair  100  or stands up from the chair  100 , the direction of the fourth head frame  145  may be adjusted so as not to interfere with the user. In another case, the direction of the fourth head frame  145  may be adjusted through manual adjustment by the user or automatic adjustment by a separate algorithm, and in this way, it may be possible to further optimize the direction in a state in which the user sits in the chair and to create a sound environment customized for the user. 
       FIG.  28    illustrates another modified example of the head frame applied to the chair illustrated in  FIG.  24   . 
     Referring to  FIG.  28   , at least one second sub-frame  170  may be disposed in directions in which the second and third head frames  150  extend. The second sub-frame  170  may have a shape that extends a predetermined length in a direction intersecting (preferably, vertically intersecting) the directions in which the second and third head frames  150  extend. 
     As in the second and third head frames  150 , the second speaker installation area in which at least one speaker  120  is installed may be defined in a direction in which the second sub-frame  170  extends. 
     Also, the second sub-frame  170  may be installed in arbitrary areas of the second and third head frames  150  with a second sub-frame rotating shaft  171  as a medium, and here, the second sub-frame  170  may be provided to be connected to the second sub-frame rotating shaft  171  to be rotatable within a predetermined angle range on a plane vertical to the ground. 
     Meanwhile, one end portion of the first head frame  140  may be installed to be hinge-rotatable about the headrest portion H with the hinge portion  142  as a medium. Also, the one end portion of the first head frame  140  and the hinge portion  142  may be connected to a lifting/lowering portion  141 . The first head frame  140  may be able to move upward a predetermined height by the lifting/lowering portion  141 . 
       FIG.  29    is a top view of a chair according to yet another embodiment of the present invention, and  FIG.  30    is a lateral view of the chair illustrated in  FIG.  29   . 
     Referring to  FIGS.  29  and  30   , at least one second sub-frame  160  may be disposed in a direction in which the first head frame  140  extends. The second sub-frame  160  may have a shape that extends a predetermined length in a direction intersecting (preferably, vertically intersecting) the direction in which the first head frame  140  extends. 
     For example, a length at which the second sub-frame  160  extends may be provided as a length to the headrest portion H from a position where the second sub-frame  160  is installed on the first head frame  140  or a length to the seat portion S from the position where the second sub-frame  160  is installed on the first head frame  140 . Accordingly, the speaker  120  installed in the second sub-frame  160  may output sounds from a side or a lower side of the user who sits in the chair  100 . 
     As in the first head frame  140 , the second speaker installation area in which at least one speaker  120  is installed may be defined in a direction in which the second sub-frame  160  extends. 
     Although not separately illustrated in the drawings, the second sub-frame  160  may also be installed on the first head frame  140  with a second sub-frame rotating shaft as a medium, and the second sub-frame  160  may be provided to be connected to the second sub-frame rotating shaft to be rotatable within a predetermined angle range in an axial direction of the second sub-frame rotating shaft. 
     Also, in this case, the second speaker installation area may be defined in at least one frame selected from the first head frame  140  and the second sub-frame  160 . 
       FIG.  31    is illustrates a modified example of the chair illustrated in  FIG.  1   . 
     Referring to  FIG.  31   , the installation frame  111  having a shape that extends in the vertical direction may be provided on the side support portions A, and the main frame  110  may be installed on the installation frame  111  with the main frame rotating shaft  113  as a medium. Here, the main frame  110  may be provided to be connected to the main frame rotating shaft  113  to be rotatable within a predetermined angle range in the axial direction of the main frame rotating shaft  113 . 
     In a case in which the main frame  110  is rotatably installed on the installation frame  111  provided on the side support portions A, the first speaker installation area SA may be defined not only in the main frame  110  but also in the side support portion A. In a case in which the first speaker installation area SA is defined in both the main frame  110  and the side support portion A, a speaker installed in the speaker installation area defined in the main frame  110  and a speaker installed in the speaker installation area defined in the side support portion A may be provided at positions not overlapping each other. 
       FIG.  32    illustrates a modified example of the chair illustrated in  FIG.  1   . 
     Referring to  FIG.  32   , the chair  100  may further include a binding portion  181  configured to bind the chair  100  to an arbitrary structure. For example, the binding portion  181  may bind the chair  100  to a structure such as furniture, a desk, or the like with a binding cable  182  as a medium to limit the movement radius of the chair  100 . 
     Also, the chair  100  may include a reception portion  183  to allow the speaker  120  installed in the main frame  110  to receive sound signals through wires. A reception cable  184  extending from the reception portion  183  may receive sound signals by being directly connected to an audio source (e.g., home theater, TV, set-top box, sound bar, computer, cellular phone, tablet PC, or the like) or being connected to an audio relay source configured to receive sound signals wirelessly from the audio source. Meanwhile, the reception portion  183  may receive sound signals wirelessly without using the reception cable  184 . 
     In a case in which the chair  100  moves excessively in a state in which the reception cable  184  is connected to the audio source or the audio relay source, there is a concern of damage to the reception cable  184 , the reception portion  183  or the audio source to which the reception cable  184  is connected, and the like, and such a problem can be prevented by binding the chair  100  to an arbitrary structure and limiting the movement radius of the chair  100  using the binding cable  182 . 
     Meanwhile, the binding portion  181  and the reception portion  183  may be integrally provided unlike those illustrated in  FIG.  32   . In this case, the binding cable  182  and the reception cable  184  may be integrally provided or provided to have different lengths. 
     Also, although not separately illustrated in the drawings, a channel processing device, such as a receiver, in charge of reception, amplification, transmission, and the like of a multi-channel sound signal may be provided in an arbitrary area of the chair  100 , and the audio source may be connected to the channel processing device to output a multi-channel sound signal corresponding to channels provided in the chair  100 . 
       FIG.  33    is a front view of a chair according to yet another embodiment of the present invention. 
     Referring to  FIG.  33   , at least one main frame  110  extending a predetermined length toward a front may be installed on the backrest portion B, and a first speaker installation area SA in which at least one speaker  120  is installed may be defined in a direction in which the main frame  110  extends. Here, the main frame  110  may be directly installed on a rear surface of the backrest portion B. 
     Meanwhile, the main frame  110  may have a shape that extends a predetermined length toward the front of the chair  100  while at a predetermined height upward from one end portion installed at the backrest portion B. 
     Embodiments of the present invention have been described above, but those of ordinary skill in the art may make various modifications and changes to the present invention by adding, changing, or omitting components within the scope not departing from the spirit of the present invention, and such modifications and changes also belong to the scope of rights of the present invention.