Patent Publication Number: US-2021173440-A1

Title: Tablet pc case and electronic apparatus

Description:
FIELD OF INVENTION 
     The present invention relates to a tablet PC case and an electronic apparatus. 
     BACKGROUND OF THE INVENTION 
     Conventionally, for example, Japanese Unexamined Patent Application Publication No. 2006-24178 discloses a foldable computer cover. The foldable computer cover can place a tablet personal computer (PC) in a standing state by having a lower edge of the tablet PC retained on a retaining block of a third plate where an input device, such as a keyboard or the like, is provided. 
     SUMMARY OF THE INVENTION 
     There is a demand for use of this type of electronic apparatuses at school or the like for an educational purpose. In using such electronic apparatuses for an educational purpose, the tablet PC may be covered with, for example, elastomeric protective covers to prevent damage to the tablet PCs. 
     In the case where a tablet PC is covered with a protective cover, however, the retaining state of the input device, such as a keyboard or the like, relative to the chassis surface is unstable when the tablet PC is placed in a standing state, and the standing posture of the tablet PC as well can be unstable. Also, a wired electrical connection between a tablet PC covered with a protective cover and an input device cannot be readily established while keeping a good appearance. Although wireless electrical connection by means of Bluetooth (registered trademark), for example, can be readily established between a tablet PC and an input device, the connection can be crossed among users in use of such electronic apparatuses for an educational purpose with a plurality of users present in the same area. Further, various kinds of sensors or the like to determine whether the mode of the electronic apparatus is in a state in which an input device is used or a state in which an input device is not used are necessary in order to prevent unintended erroneous input, which complicates the structure. 
     In view of the above-described situation, one object of the present invention is to provide a tablet PC case and an electronic apparatus that can prevent damage to a tablet PC and stably maintain the posture of the tablet PC in a standing state, and allows ready establishment of wired electrical connection between the tablet PC and an input device while keeping a good appearance. 
     A tablet PC case according to one aspect of the present invention includes a first protective cover having an opening in which a display surface of a tablet PC is exposed, the first protective cover being capable of housing the tablet PC therein; a second protective cover configured to cover the opening of the first protective cover so as to open or close the opening; and a connection unit connecting the first protective cover and the second protective cover in a relatively movable manner, the connection unit being capable of holding the first protective cover in a standing state in which the first protective cover stands on the second protective cover, wherein the first protective cover includes a frame body covering the outer circumferential portion of the tablet PC, the frame body being capable of holding the tablet PC, the frame body includes a pair of retained frame portions extending along one edge of the outer circumferential portion of the tablet PC, the one edge being opposed to the second protective cover in the standing state, the pair of retained frame portions being disposed at an interval in the extending direction in which the one edge extends, the retained frame portion includes an outer surface portion like a curved convex surface, extending in the extending direction, and a first end face positioned on the inside end portion of the retained frame portion in the extending direction, the first end face being directed inward in the extending direction, the second protective cover includes a chassis having a plate external shape, an input unit held in the chassis, the input unit being formed on the inner surface of the second protective cover, a terminal group exposed on the inner surface of the second protective cover in a position closer to the connection unit than the input unit, the terminal group being electrically connectable to the lateral surface of the tablet PC in the standing state, and a magnet portion disposed inside the chassis, the magnet being capable of attracting the tablet PC by means of a magnetic force when the terminal group is connected to the tablet PC, the chassis has a groove portion recessed from the front surface of the chassis and extending in the extending direction, the groove portion includes a first groove extending in the extending direction so that the one edge of the tablet PC in the standing state is able to be retained in the first groove, and a pair of second grooves disposed on respective both sides of the first groove in the extending direction and extending in the extending direction so that the pair of retained frame portions is retained in the standing state in the pair of second grooves, the second groove includes a groove base surface like a curved concave surface, the groove base surface extending in the extending direction, the groove base surface being in contact with the outer surface portion, and a second end face positioned on the inside end portion of the second groove in the extending direction, the second end face being directed outward in the extending direction, the second end face being opposed to the first end face in the standing state, and the terminal group is disposed in the first groove. 
     An electronic apparatus according to one aspect of the present invention includes the above-described tablet PC case, and the tablet PC to be housed in the first protective cover. 
     According to a tablet PC case and an electronic apparatus according to the aspects of the present invention, it is possible to prevent damage to the tablet PC case, to stabilize the posture of the tablet PC in a standing state, and to readily establish wired electrical connection between the tablet PC and an input device while keeping a good appearance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an electronic apparatus according to an embodiment of the present invention in a use state of an input device; 
         FIG. 2  is a perspective view of a tablet PC case according to an embodiment of the present invention in a use state of an input device; 
         FIG. 3  is a perspective view of a tablet PC case according to an embodiment of the present invention in a use state of an input device; 
         FIG. 4  is a front view of a tablet PC case according to an embodiment of the present invention in a use state of an input device; 
         FIG. 5  is a rear view of a tablet PC case according to an embodiment of the present invention in a use state of an input device; 
         FIG. 6  is a plan view of a tablet PC case according to an embodiment of the present invention in a use state of an input device; 
         FIG. 7  is a bottom view of a tablet PC case according to an embodiment of the present invention in a use state of an input device; 
         FIG. 8  is a left side view of a tablet PC case according to an embodiment of the present invention in a use state of an input device; 
         FIG. 9  is a right side view of a tablet PC case according to an embodiment of the present invention in a use state of an input device; 
         FIG. 10  is an enlarged perspective view of the X portion in  FIG. 2 ; 
         FIG. 11  is a partial perspective view of a major portion of a tablet PC case according to an embodiment of the present invention, the major portion being illustrated with a solid line; 
         FIG. 12  is a partial plan view of a major portion of a tablet PC case according to an embodiment of the present invention; 
         FIG. 13  is a cross sectional view of a cross section along line XIII-XIII in  FIG. 12  with a magnet portion not illustrated; 
         FIG. 14  is a partial perspective view of a major portion of a tablet PC case according to an embodiment of the present invention; 
         FIG. 15  is a perspective view of an electronic apparatus according to an embodiment of the present invention in a folded state; 
         FIG. 16  is a perspective view of an electronic apparatus according to an embodiment of the present invention in a folded state; 
         FIG. 17  is a front view of a tablet PC case according to an embodiment of the present invention in a folded state; 
         FIG. 18  is a rear view of a tablet PC case according to an embodiment of the present invention in a folded state; 
         FIG. 19  is a plan view of a tablet PC case according to an embodiment of the present invention in a folded state; 
         FIG. 20  is a bottom view of a tablet PC case according to an embodiment of the present invention in a folded state; 
         FIG. 21  is a left side view of a tablet PC case according to an embodiment of the present invention in a folded state; 
         FIG. 22  is a right side view of a tablet PC case according to an embodiment of the present invention in a folded state; and 
         FIG. 23  is a partial perspective view of a modified example of a tablet PC case according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A tablet PC case  1  and an electronic apparatus  10  according to an embodiment of the present invention will now be described referring to the drawings. 
     In this embodiment, an XYZ rectangular coordinate system is set in each drawing to describe the positional relationship of the respective structures. Specifically, in the following, a direction along the X axis will be referred to as a right-left direction; a direction along the Y axis will be referred to as a front-rear direction; and a direction along the Z axis will be referred to as an up-down direction. As to the X axial direction, the +X side is the right side, and the −X side is the left side. As to the Y axial direction, the +Y side is the rear side; and the −Y side is the front side. As to the Z axial direction, the +Z side is the upper side, and the −Z side is the lower side. 
     As illustrated in  FIG. 1 ,  FIG. 15 , and  FIG. 16 , the electronic apparatus  10  in this embodiment includes a tablet PC  50  and a tablet PC case  1 . The tablet PC  50  has a plate external shape, and is removably mounted in the tablet PC case  1 . Specifically, the tablet PC  50  is housed in a first protective cover  2 , to be described later, of the tablet PC case  1 . 
     Note that, in this embodiment,  FIG. 1 ,  FIG. 15 , and  FIG. 16  illustrate the electronic apparatus  10 , that is, the tablet PC  50  mounted in the tablet PC case  1 , while the drawings other than  FIG. 1 ,  FIG. 15 , and  FIG. 16  illustrate solely the tablet PC case  1 . 
     In this embodiment, as illustrated in  FIG. 1 , a state in which the tablet PC  50  is housed in the first protective cover  2  of the tablet PC case  1 , standing on a second protective cover  3 , to be described later, that is, the first protective cover  2  stands on the second protective cover  3 , is referred to as a standing state, a standing state of the tablet PC  50 , or a standing posture. The standing state of the tablet PC  50  is a state in which one edge  50   a  of the outer circumferential portion of the tablet PC  50  is in contact with a chassis  11 , to be described later, of the second protective cover  3 , and a display (a display surface)  51 , to be described later, of the tablet PC  50  is directed toward a user, not illustrated, or the front side (the −Y side). 
     With this electronic apparatus  10 , when the tablet PC  50  is in the standing state, the tablet PC  50  is electrically connected to an input unit (an input device)  12 , to be described later, of the second protective cover  3 , so that input via the input unit  12 , or use of the input device, is enabled. Thus, the standing state of the tablet PC  50  can be rephrased as a state in which an input device is used, or a use state of an input device.  FIG. 1  to  FIG. 10  illustrate the use state of the input device. 
     As illustrated in  FIG. 15  and  FIG. 16 , a state in which the display  51  of the tablet PC  50  is opposed to the front surface (a first cover  11   a  to be described later) of the chassis  11  of the second protective cover  3 , that is, the tablet PC  50  and the first protective cover  2  and the second protective cover  3  are folded so as to be disposed one on the other is referred to as a folded state or a folded posture. 
     When the electronic apparatus  10  is in the folded state, electrical connection between the tablet PC  50  and the input unit  12  is disconnected, so that input via the input unit  12 , that is, use of an input device, is disabled. Thus, the folded state can be rephrased as a state in which the input device is not used.  FIG. 15  to  FIG. 22  illustrates the folded state. 
     As illustrated in  FIG. 1 ,  FIG. 15 , and  FIG. 16 , the tablet PC  50  has a quadrilateral plate external shape. Specifically, the tablet PC  50  has an external shape like a rectangular plate or a low-profile rectangular parallelepiped. Thus, the four edges constituting the outer circumferential portion of the tablet PC  50  include a pair of longer edges and a pair of shorter edges. The pair of longer edges extends in the right-left direction. 
     The tablet PC  50  includes the display  51 , a tablet terminal, not illustrated, a tablet magnet portion, not illustrated, a power button  57 , a volume adjustment button  58 , a plug connection unit  52 , a microphone unit  53 , a speaker unit  54 , a front camera unit  55 , and a rear camera unit  56 . 
     The display  51  is disposed on one of a pair of plate surfaces of the tablet PC  50 . The display  51  is, for example, a liquid crystal display, an organic electroluminescent (EL) display, or the like. With the tablet PC  50  in the standing state, the display  51  is directed forward (the −Y side). Meanwhile, in the folded state, the display  51  is directed downward (the −Z side). 
     Although not particularly illustrated, the tablet terminal is disposed on one edge  50   a , or one of the pair of longer edges of the four edges of the outer circumferential portion of the tablet PC  50 . That is, the tablet terminal is disposed on the lateral surface of the tablet PC  50 . Note that the one edge  50   a  is an edge positioned on the lower end portion of the tablet PC  50  when the tablet PC  50  is in the standing state, as illustrated in  FIG. 1 . That is, the one edge  50   a  is a lower edge of the tablet PC  50 , the lower edge being opposed to the chassis  11  of the second protective cover  3 . In other words, the one edge  50   a  is an edge of the outer circumferential portion of the tablet PC  50 , the edge being opposed to the second protective cover  3  in the standing state. A plurality of the tablet terminals is disposed exposed on the one edge  50   a  of the tablet PC  50 . The plurality of tablet terminals can be rephrased as a tablet terminal group. The plurality of tablet terminals is disposed at intervals in the extending direction of the one edge  50   a . In this embodiment, the extending direction of the one edge  50   a  corresponds to the right-left direction (the X axial direction). 
     Although not particularly illustrated, the tablet magnet portion is held inside the tablet PC  50 . Specifically, the tablet magnet portion is disposed along the one edge  50   a  of the outer circumferential portion in the tablet PC  50 . That is, the tablet magnet portion is positioned inside the one edge  50   a  of the tablet PC  50 , and extends in the right-left direction. The tablet magnet portion is disposed on the lateral surface of the tablet PC  50 . 
     As illustrated in  FIG. 16 , the power button  57 , the volume adjustment button  58 , and the plug connection unit  52  are disposed on an edge  50   b , or an edge of the pair of shorter edges, or an edge different from the one edge  50   a  of the four edges of the outer circumferential portion of the tablet PC  50 . The one edge  50   b  is an edge positioned on the right side of the pair of shorter edges of the tablet PC  50 , that is, the right edge of the tablet PC  50 . The power button  57 , the volume adjustment button  58 , and the plug connection unit  52  are disposed at intervals on the one edge  50   b.    
     The microphone unit  53  and the speaker unit  54  are disposed on an edge  50   c , or an edge of the pair of longer edges, or an edge different from the edges  50   a ,  50   b  of the four edges of the outer circumferential portion of the tablet PC  50 . As illustrated in  FIG. 1 , the edge  50   c  is an edge positioned on the upper end portion of the tablet PC  50  when the tablet PC  50  is in the standing state, or the upper edge of the tablet PC  50 . 
     As illustrated in  FIG. 16 , a plurality of the microphone units  53  is provided on the one edge  50   c  at intervals in the right-left direction. A plurality of the speaker units  54  is provided on the one edge  50   c  at intervals in the right-left direction. 
     As illustrated in  FIG. 1 , the front camera unit  55  is disposed on an edge portion of one of the pair of plate surfaces of the tablet PC  50 , specifically, on the upper edge portion of one plate surface, the upper edge portion being in adjacent to the one edge  50   c.    
     As illustrated in  FIG. 15 , the rear camera unit  56  is disposed at a corner of the other one of the pair of plate surfaces of the tablet PC  50 , specifically, at a corner (the upper right corner) of the other plate surface, the corner being adjacent to the edges  50   b ,  50   c.    
     As illustrated in  FIG. 1  to  FIG. 9 , the tablet PC case includes the first protective cover  2 , the second protective cover  3 , and a connection unit  4 . 
     The first protective cover  2  has an opening  2   a  in which the display  51  of the tablet PC  50  is exposed, and can house the tablet PC  50  therein. The first protective cover  2  is made of, for example, elastomer, such as thermo plastic polyurethane, or the like. The first protective cover  2  is elastically deformable. 
     The first protective cover  2  includes a rear plate  5  and a frame body  6 . 
     The rear plate  5  is shaped like a plate. The rear plate  5  is shaped like a quadrilateral plate, specifically, a rectangular plate. Of the four edges of the outer edge portion of the rear plate  5 , a pair of longer edges extend in the right-left direction. The rear plate  5  is opposed to the other plate surface of the pair of plate surfaces of the tablet PC  50 . The rear plate  5  is in contact with the other plate surface of the tablet PC  50 , and covers the other plate surface. 
     The rear plate  5  has a rear camera hole  5   a . The rear camera hole  5   a  is shaped like a round hole penetrating the rear plate  5  and open on the pair of plate surfaces of the rear plate  5 . The rear camera hole  5   a  is disposed opposed to the rear camera unit  56  of the tablet PC  50 . 
     The frame body  6  is connected to the outer edge portion of the rear plate  5 , covers the outer circumferential portion of the tablet PC  50 , and can hold the tablet PC  50 . The frame body  6  is opposed to the four edges of the outer circumferential portion of the tablet PC  50 . The frame body  6  covers the respective entire lengths of the pair of shorter edges and the one edge  50   c  of the pair of longer edges of the four edges of the outer circumferential portion of the tablet PC  50 . In addition, the frame body  6  covers at least the both end portions of the one edge  50   a  of the four edges of the outer circumferential portion of the tablet PC  50 . 
     The frame body  6  includes an upper frame portion  7 , a pair of side frame portion  8 , and a pair of retained frame portions  9 . 
     The upper frame portion  7  extends along the one edge  50   c  of the pair of longer edges of the outer circumferential portion of the tablet PC  50 . The upper frame portion  7  is opposed to the one edge  50   c  of the tablet PC  50 . The upper frame portion  7  is in contact with the one edge  50   c  of the tablet PC  50 , and covers the one edge  50   c . The outer circumferential surface of the upper frame portion  7  is like a curved convex surface extending in the right-left direction. The inner circumferential surface of the upper frame portion  7  is like a curved concave surface extending in the right-left direction. With the tablet PC  50  in the standing state, the cross sectional shape of the upper frame portion  7  perpendicular to the right-left direction has an upward convex C-shape. 
     The upper frame portion  7  includes a microphone hole  7   a  and a speaker hole  7   b.    
     The microphone hole  7   a  is shaped like a round hole penetrating the upper frame portion  7  in a direction in which the upper frame portion  7  is thicker. The microphone hole  7   a  is disposed opposed to the microphone unit  53  of the tablet PC  50 . A plurality of the microphone holes  7   a  is provided on the upper frame portion  7  at intervals in the right-left direction. 
     The speaker hole  7   b  is shaped like a long hole extending in the right-left direction and penetrating the upper frame portion  7  in a direction in which the upper frame portion  7  is thicker. The speaker hole  7   b  is disposed opposed to the speaker unit  54  of the tablet PC  50 . A plurality of the speaker holes  7   b  is provided on the upper frame portion  7  at intervals in the right-left direction. 
     A pair of side frame portions  8  extends along the pair of respective shorter edges of the outer circumferential portion of the tablet PC  50 . The side frame portion  8  is opposed to the shorter edge of the tablet PC  50 . The side frame portion  8  is in contact with the shorter edge of the tablet PC  50 , and covers the shorter edge. The outer circumferential surface of the side frame portion  8  is like a curved convex surface extending in the extending direction of the shorter edge. The inner circumferential surface of the side frame portion  8  is like a curved concave surface extending in the extending direction of the shorter edge. Of the pair of side frame portions  8 , the side frame portion positioned on the left side has a cross section perpendicular to the extending direction of the shorter edge, the cross section being shaped like a leftward convex C-shape. Of the pair of side frame portions  8 , the side frame portion  8  positioned on the right side has a cross section perpendicular to the extending direction of the shorter edge, the cross section being shaped like a rightward convex C-shape. 
     The side frame portion  8  includes a cushion rib  8   a , a power operation unit  8   b , a volume adjustment unit  8   c , and a plug connection hole  8   d.    
     As illustrated in  FIG. 2 , the cushion rib  8   a  is disposed on the inner circumferential surface of the side frame portion  8  and in contact with the shorter edge of the outer circumferential portion of the tablet PC  50 . The cushion rib  8   a  extends in a direction orthogonal to the extending direction of the shorter edge of the tablet PC  50 , that is, a direction orthogonal to the extending direction of the side frame portion  8 . A plurality of the cushion ribs  8   a  is disposed at intervals in the extending direction of the side frame portion  8 . 
     As illustrated in  FIG. 3  and  FIG. 16 , the power operation unit  8   b , the volume adjustment unit  8   c , and the plug connection hole  8   d  are disposed on the side frame portion  8  positioned on the right side (the +X side) of the pair of side frame portions  8 . 
     The power operation unit  8   b  is disposed opposed to the power button  57  of the tablet PC  50 . In response to a user&#39;s operating the power operation unit  8   b , the power button  57  is pressed via the power operation unit  8   b , whereby the power is turned on or off. 
     The volume adjustment unit  8   c  is disposed opposed to the volume adjustment button  58  of the tablet PC  50 . In response to a user&#39;s operating the volume adjustment unit  8   c , the volume adjustment button  58  is pressed via the volume adjustment unit  8   c , whereby the sound volume increases or decreases. 
     The plug connection hole  8   d  is a long opening extending in the extending direction of the side frame portion  8  and penetrating the side frame portion  8  in a direction in which the side frame portion  8  is thicker. The plug connection hole  8   d  is disposed opposed to the plug connection unit  52  of the tablet PC  50 . 
     As illustrated in  FIG. 1 ,  FIG. 2 ,  FIG. 10 , and  FIG. 14 , the pair of retained frame portions  9  extends along the one edge  50   a  of the pair of longer edges of the outer circumferential portion of the tablet PC  50 . The retained frame portion  9  is opposed to the one edge  50   a  of the tablet PC  50 . The retained frame portion  9  is in contact with the one edge  50   a  of the tablet PC  50 , and covers a part of the one edge  50   a  in the extending direction (the right-left direction). The pair of retained frame portions  9  is disposed at an interval in the extending direction in which the one edge  50   a  extends. Specifically, the pair of retained frame portions  9  is disposed on the respective both end portions of the one edge  50   a  in the extending direction. 
     The retained frame portion  9  has a cross section perpendicular to the extending direction of the one edge  50   a  (the right-left direction), that is shaped like a downward convex C-shape with the tablet PC  50  in the standing state. 
     Note that in the description below, unless otherwise stated, an “extending direction” refers to the extending direction of the one edge  50   a , that is, the right-left direction. “Inward in the extending direction” refers to a direction from the respective both end portions of the one edge  50   a  in the extending direction toward the middle portion, and “outward in the extending direction” refers to a direction from the middle portion of the one edge  50   a  in the extending direction toward the respective both end portions. 
     The retained frame portion  9  includes an outer surface portion  9   a  like a curved convex surface extending in the extending direction, an inner surface portion  9   b  like a curved concave surface extending in the extending direction, and a first end face  9   c  positioned on the inside end portion of the retained frame portion  9  in the extending direction and directed inward in the extending direction. 
     The outer surface portion  9   a  has a cross section perpendicular to the external direction, that is shaped like a curved convex line. Note that the outer surface portion  9   a  may have a cross section perpendicular to the extending direction, whose shape includes a portion like a curved convex line and a portion like a straight line. 
     The inner surface portion  9   b  has a cross section perpendicular to the extending direction, the cross section being shaped like a curved concave line. Note that the inner surface portion  9   b  may have a cross section perpendicular to the extending direction, whose shape includes a portion like a curved concave line and a portion like a straight line. 
     The first end face  9   c  is like a flat surface expanding in a direction perpendicular to the extending direction, and is shaped like an arc as a whole when viewed in the extending direction. Of the pair of retained frame portions  9 , the first end face  9   c  of the retained frame portion  9  positioned on the left side is directed rightward. Meanwhile, of the pair of retained frame portions  9 , the first end face  9   c  of the retained frame portion  9  positioned on the right side is directed leftward. The respective first end faces  9   c  of the pair of retained frame portions  9  are disposed opposed to each other at an interval in the extending direction. In this embodiment, the distance between the respective first end faces  9   c  of the pair of retained frame portions  9  in the extending direction is longer than the length of each retained frame portion  9  in the extending direction. 
     As illustrated in  FIG. 1 ,  FIG. 15 , and  FIG. 16 , the second protective cover  3  has a structure that covers the opening  2   a  of the first protective cover  2  to open or close the opening  2   a.    
     As illustrated in  FIG. 1 ,  FIG. 2 , and in  FIG. 12 , the second protective cover  3  includes the chassis  11 , the input unit  12 , a terminal group  13 , and a magnet portion  14 . The chassis  11  has a plate external shape. The input unit  12  is held in the chassis  11  and formed on the inner surface of the second protective cover  3 . The terminal group  13  is exposed on the inner surface of the second protective cover  3  in a position closer to the connection unit  4  than the input unit  12 , and is electrically connectable to the lateral surface of the tablet PC  50  in the standing state. The magnet portion  14  is disposed inside the chassis  11 , and can attract the tablet PC  50  with a magnetic force when the terminal group  13  is connected to the tablet PC  50 . Note that the inner surface of the second protective cover  3  corresponds to the front surface of the chassis  11  of the second protective cover  3 , that is, a first cover  11   a  to be described later. In this embodiment, the input unit  12  is a keyboard. In the description below, the input unit  12  may be referred to as a keyboard  12  in some cases. 
     The chassis  11  is like a box, and has a storage space inside. The chassis  11  is made of resin, such as plastic, for example. The chassis  11  has a quadrilateral plate external shape. Specifically, the chassis  11  has an external shape like a rectangular plate or a low-profile rectangular parallelepiped. Thus, the four edges constituting the outer circumferential portion of the chassis  11  include a pair of longer edges and a pair of shorter edges. The pair of longer edges extends in the right-left direction. 
     As illustrated in  FIG. 19  and  FIG. 20 , the outer dimension of the chassis  11  in a plan view when viewed in the thickness direction (the X axial dimension and the Y axial dimension) is substantially the same as the outer dimension of the first protective cover  2  in a plan view when viewed in the thickness direction of the rear plate  5 . As illustrated in  FIG. 17 , the length of the chassis  11  in the thickness direction, that is, the thickness dimension (the Z axial dimension), is shorter than the length of the first protective cover  2  in the thickness direction, that is, in the thickness dimension. 
     As illustrated in  FIG. 1 ,  FIG. 2 , and  FIG. 16 , the chassis  11  includes a first cover  11   a , a second cover  11   b , a lateral surface  11   c , and a groove portion  15 . 
     The first cover  11   a  and the second cover lib constitute the front outer surface and the rear outer surface, respectively, of the chassis  11 , the front outer surface and the rear outer surface being directed in the thickness direction of the chassis  11 . That is, the first cover  11   a  and the second cover lib are directed opposite from each other in the thickness direction of the chassis  11 . Specifically, the first cover  11   a  constitutes the front outer surface of the chassis  11 , while the second cover lib constitutes the rear outer surface of the chassis  11 . 
     In the folded state illustrated in  FIG. 16 , the first cover  11   a  is opposed to the display  51  of the tablet PC  50 . That is, the first cover  11   a  is directed in the thickness direction of the chassis  11 , and can be opposed to the display  51 . 
     As illustrated in  FIG. 2 , the first cover  11   a  includes a dish portion  11   d . The dish portion  11   d  has an opening where the keys of the keyboard (an input unit)  12  are disposed. That is, in the dish portion  11   d , the keyboard  12  is disposed. The dish portion  11   d  is shaped quadrilateral in a plan view when viewed in the thickness direction, specifically, rectangular. The dish portion  11   d  has four edges on the circumferential edge of the dish portion  11   d . Each edge constitutes a part of the circumferential edge of the dish portion  11   d.    
     The second cover lib is directed opposite from the first cover  11   a  in the thickness direction. The second cover  11   b  is directed opposite from the tablet PC  50  in the folded state and when the tablet PC  50  is in the standing state. 
     Note that, besides the folded state in the manner described above, that is, a first folded state in which the display  51  of the tablet PC  50  is disposed opposed to the first cover  11   a , the electronic apparatus  10  and the tablet PC case  1  in this embodiment can be placed in a second folded state, not particularly illustrated, in which the rear plate  5  of the first protective cover  2  is disposed opposed to the second cover  11   b . In the second folded state, the rear plate  5  is in contact with the second cover  11   b.    
     In the first folded state and the second folded state, the lateral surface of the tablet PC  50  is separated from the terminal group  13 , so that electrical connection between the tablet PC  50  and the input unit  12  is disconnected. That is, input via the input unit  12 , that is, use of the input device, is disabled. In the second folded state, a user can visually check the display  51  of the tablet PC  50  and execute touch operation relative to the display  51 , that is, the display  51  is usable. 
     The lateral surface  11   c  is a part of the outer surface of the chassis  11 , the part being directed in a direction orthogonal to the thickness direction of the chassis  11 . A plurality of the lateral surfaces  11   c  is provided. 
     Specifically, four lateral surfaces  11   c  are provided in this embodiment. The plurality of lateral surfaces  11   c  includes a lateral surface  11   c  directed forward (the −Y side), a lateral surface  11   c  directed rearward (the +Y side), a lateral surface  11   c  directed leftward (the −X side), and a lateral surface  11   c  directed rightward (the +X side). The plurality of lateral surfaces  11   c  connects the front surface and the rear surface of the chassis  11 . That is, the lateral surfaces  11   c  connect the first cover  11   a  and the second cover lib. 
     As illustrated in  FIG. 10  to  FIG. 13 , the groove portion  15  is recessed from the front surface of the chassis and extends in the extending direction. The groove portion  15  is a groove recessed downward (the −Z side) from the first cover  11   a , and extends in the right-left direction (the X axial direction). In this embodiment, the groove portion  15  is disposed over the entire length of the front surface of the chassis  11  in the extending direction. The groove portion  15  is disposed on a rear portion of the first cover  11   a . The groove portion  15  is positioned further rearward than the dish portion  11   d.    
     The groove portion  15  includes a first groove  16  and a pair of second grooves  17 . The first groove  16  extends in the extending direction, and the one edge  50   a  of the tablet PC  50  can be retained in the first groove  16  when the tablet PC  50  is in the standing state. The second grooves  17  are disposed on the respective both sides of the first groove  16  in the extending direction, and extend in the extending direction. The pair of retained frame portions  9  is retained in the pair of second grooves  17  when the tablet PC  50  is in the standing state. 
     The first groove  16  is disposed in the middle portion between the respective both end portions of the groove portion  15  in the extending direction. The first groove  16  has a curved concave base surface  16   a  extending in the extending direction. 
     The base surface  16   a  has a cross section perpendicular to the extending direction, the cross section being shaped like a curved concave line recessed downward. The base surface  16   a  has a terminal disposition rib  16   b  projecting from the base surface  16   a  toward the inside of the first groove  16 . 
     The terminal disposition rib  16   b  is disposed in the middle portion of the base surface  16   a  in the extending direction. The terminal disposition rib  16   b  extends in the extending direction. 
     The pair of second grooves  17  is disposed on the respective both end portions of the groove portion  15  in the extending direction. The groove width of each second groove  17 , that is, the width in the front-rear direction (the Y axial direction), is wider than that of the first groove  16 . The groove depth of each second groove  17 , that is, the depth in the up-down direction (the Z axial direction), is deeper than that of the first groove  16 . The length of the first groove  16  in the extending direction, that is, the length in the right-left direction (the X axial direction), is longer than that of the second groove  17  in the extending direction. 
     Each second groove  17  includes a groove base surface  17   a , a second end face  17   b , and a blocking wall  17   c . The groove base surface  17   a  extends in the extending direction and is like a curved concave surface in contact with the outer surface portion  9   a  of the retained frame portion  9 . The second end face  17   b  is positioned on the inside end portion of the second groove  17  in the extending direction, and is directed outward in the extending direction so as to be opposed to the first end face  9   c  of the retained frame portion  9  when the tablet PC  50  is in the standing state. The blocking wall  17   c  is positioned on the outside end portion of the second groove  17  in the extending direction. 
     The groove base surface  17   a  has a cross section perpendicular to the extending direction, the cross section being shaped like a curved concave line recessed downward. In a cross sectional view perpendicular to the extending direction, the curvature radius of the groove base surface  17   a  is larger than that of the base surface  16   a.    
     The second end face  17   b  is like a flat surface expanding in a direction perpendicular to the extending direction, and is shaped like an arc as a whole when viewed in the extending direction. Of the pair of second grooves  17 , the second end face  17   b  of the second groove  17  positioned on the left side is directed leftward. Meanwhile, of the pair of second grooves  17 , the second end face  17   b  of the second groove  17  positioned on the right side is directed rightward. The respective second end faces  17   b  of the pair of second grooves  17  are disposed directed opposite from each other at an interval in the extending direction. 
     Of the pair of second grooves  17 , the second end face  17   b  of the second groove  17  positioned on the left side is opposed to the first end face  9   c  of the retained frame portion  9  positioned on the left side of the pair of retained frame portions  9  with a space therebetween in the extending direction or in contact with the first end face  9   c.    
     Meanwhile, of the pair of second grooves  17 , the second end face  17   b  of the second groove  17  positioned on the right side is opposed to the first end face  9   c  of the retained frame portion  9  positioned on the right side of the pair of retained frame portions  9  with a space therebetween in the extending direction or in contact with the first end face  9   c.    
     The blocking wall  17   c  blocks the second groove  17  from outside in the extending direction. The blocking wall  17   c  is made using a part of the lateral surface  11   c . The surface of the blocking wall  17   c  directed inward in the extending direction is like a flat surface expanding in a direction perpendicular to the extending direction. The blocking wall  17   c  is opposed to the outside end portion of the retained frame portion  9  in the extending direction, in the extending direction. 
     The keyboard  12  is at least partially disposed on the first cover  11   a , which constitutes the inner surface (the front surface) of the second protective cover  3 , that is, the front surface of the chassis  11 . 
     The keyboard  12  includes a plurality of keys and a back plate (not illustrated). The plurality of keys is a part of the keyboard  12 , the part being exposed upward (the +Z side) in the opening of the dish portion  11   d . The plurality of keys is aligned in the respective right-left and front-rear directions. The back plate is a part of the keyboard  12 , the part being disposed inside the chassis  11  and supporting the plurality of keys. 
     The terminal group  13  is disposed in the first groove  16 . The terminal group  13  is exposed in the first groove  16 . The terminal group  13  projects from the base surface  16   a  into the inside of the first groove  16 . The terminal group  13  is disposed in the terminal disposition rib  16   b . The terminal group  13  includes a plurality of terminals  13   a  disposed aligned in the extending direction. The terminal group  13  includes a terminal (a first terminal)  13   a  to feed power from the tablet PC  50  to the keyboard  12 , and a terminal (a second terminal)  13   a  to output an input signal from the keyboard  12  to the tablet PC  50 . 
     The terminal  13   a  projects from the base surface  16   a  of the first groove  16  to the inside of the first groove  16 , and includes a pin portion whose amount of projection is changeable and an urging portion (not illustrated) to urge the pin portion in a direction in which the pin portion projects from the base surface  16   a . That is, the terminal group  13  includes the pin portion and the urging portion. 
     The terminal  13   a  retractably projects from the base surface  16   a  while being urged upward. The terminal  13   a  in this embodiment is a so-called pogo pin. 
     As illustrated in  FIG. 12 , the magnet portion  14  is disposed on the backside of the first groove  16  inside the chassis  11 . That is, the magnet portion  14  is positioned inside the first groove  16  in the chassis  11 . In a plan view of the chassis  11  illustrated in  FIG. 12  when viewed in the thickness direction, the magnet portion  14  is disposed overlapping the first groove  16 . In  FIG. 13 , the magnet portion  14  is not illustrated. The magnet portion  14  extends in the extending direction. With the tablet PC  50  in the standing state, the magnet portion  14  is disposed close to the one edge  50   a  of the tablet PC  50 . The magnet portion  14  attracts the tablet magnet portion of the tablet PC  50  by means of a magnetic force to thereby attract the lateral surface of the tablet PC  50 . 
     As illustrated in  FIG. 3 , the connection unit  4  connects the first protective cover  2  and the second protective cover  3  in a relatively movable manner. The connection unit  4  can hold the first protective cover  2  and the second protective cover  3  in such a manner that the first protective cover  2  stands on the second protective cover  3 , or in the standing state. 
     The connection unit  4  includes a support plate  4   a  connected to the first protective cover  2  and capable of supporting the first protective cover  2 , and a deformable flexible sheet  4   b  connecting the support plate  4   a  and the second protective cover  3 . 
     With the tablet PC  50  in the standing state, the support plate  4   a  supports the tablet PC  50 , housed in the first protective cover  2  and the first protective cover  2 , from the rear side of the tablet PC  50 . The support plate  4   a  is shaped like a plate. That is, the support plate  4   a  is shaped like a quadrilateral plate, specifically, a rectangular plate. Of the four edges of the outer edge portion of the support plate  4   a , a pair of longer edges  4   c ,  4   d  extends in the right-left direction. Of the pair of longer edges  4   c ,  4   d  of the support plate  4   a , one longer edge  4   c  is connected to the rear plate  5  of the first protective cover  2 . The longer edge  4   c  of the support plate  4   a  is connected to the middle portion of the rear plate  5 , the middle portion being positioned between the respective both end portions in the direction in which the side frame portion  8  extends. Of the pair of longer edges  4   c ,  4   d , a longer edge different from the longer edge  4   c , namely, the longer edge  4   d , is connected to the flexible sheet  4   b.    
     When the tablet PC  50  is in the standing state, the longer edge  4   c  is positioned on the upper end portion of the support plate  4   a , and the longer edge  4   d  is positioned on the lower end portion of the support plate  4   a . As illustrated in  FIG. 15 , in the folding state, one plate surface of a pair of plate surfaces of the support plate  4   a  is in contact with the rear plate  5 . In the folded state, the support plate  4   a  covers at least a part of the rear plate  5 . 
     As illustrated in  FIG. 3  and  FIG. 15 , the flexible sheet  4   b  is a deformable sheet. The flexible sheet  4   b  is a quadrilateral sheet, specifically, a rectangular sheet. Of the four edges of the outer edge portion of the flexible sheet  4   b , a pair of longer edges  4   e ,  4   f  extends in the right-left direction. Of the pair of longer edges  4   e ,  4   f  of the flexible sheet  4   b , one longer edge  4   e  is connected to the longer edge  4   d  of the support plate  4   a . Meanwhile, of the pair of longer edges  4   e ,  4   f , a longer edge different from the longer edge  4   e , namely, the longer edge  4   f , is connected to the lateral surface  11   c  directed rearward (the +Y side) of the chassis  11 . The length (width) of the flexible sheet  4   b  in the right-left direction is shorter than that of the support plate  4   a  in the right-left direction. 
     As illustrated in  FIG. 15 , in the folded state, the flexible sheet  4   b  deforms like the spine portion of a book, and covers the one edge  50   a  of the outer circumferential portion of the tablet PC  50 , that is, the lateral surface of the tablet PC  50 , and one edge of the outer circumferential portion of the chassis  11 , that is, the lateral surface  11   c  directed rearward. 
     The above-described tablet PC case  1  and the electronic apparatus  10  according to the above-described embodiment can prevent damage to the tablet PC  50 , for example, even when the electronic apparatus  10  is used at school or the like for an educational purpose as the tablet PC  50  is housed in the first protective cover  2  and thereby protected against an impact or the like. In addition, in the folded state, the tablet PC  50  is protected against an impact or the like also with the second protective cover  3 . 
     In the use state of the input device, or in a state in which the tablet PC  50  stands on the chassis  11  of the second protective cover  3 , the one edge  50   a  of the outer circumferential portion of the tablet PC  50 , that is, the lateral surface of the tablet PC  50 , is retained directly in the first groove  16  of the groove portion  15  of the chassis  11 , and the pair of retained frame portions  9  of the first protective cover  2  is retained in the pair of second grooves  17  of the groove portion  15 . Thus, compared with a case, for example, in which only the frame body  6  of the first protective cover  2  is retained in the groove portion  15 , and the outer circumferential portion of the tablet PC  50  is not retained in the groove portion  15 , different from this embodiment, this embodiment can stabilize the retaining state between the tablet PC  50  and the groove portion  15  as the outer circumferential portion of the tablet PC  50  is retained directly in the groove portion  15 , and thereby stabilize the standing posture of the tablet PC  50 . Specifically, according to this embodiment, displacement of the tablet PC  50  and the groove portion  15  in the front-rear direction, in particular, can be prevented. 
     Also, as the respective first end faces  9   c  of the pair of retained frame portions  9  are disposed opposed to the respective second end faces  17   b  of the pair of second grooves  17  in the extending direction of the one edge  50   a  of the tablet PC  50 , deficiency such as sliding movement of the tablet PC  50  in the standing state in the extending direction in the groove portion  15  is prevented. Specifically, according to this embodiment, displacement of the tablet PC  50  and the groove portion  15  in the right-left direction in particular can be prevented. 
     Also, as the magnet portion  14  provided on the backside of the first groove  16  in the chassis  11  attracts the tablet PC  50  by means of a magnetic force without intervention of the frame body  6  of the first protective cover  2 , deficiency such as removal of the tablet PC  50  from the groove portion  15  is prevented. Specifically, according to this embodiment, separation of the tablet PC  50  and the groove portion  15  in the up-down direction in particular can be prevented. 
     That is, this embodiment prevents relative movements of the tablet PC  50  and the groove portion  15  in the front-rear direction (the Y axial direction), the right-left direction (the X axial direction), and the up-down direction (the Z axial direction), respectively. 
     Also, the curved convex outer surface portion  9   a  of the retained frame portion  9  is in contact with the curved concave groove base surface  17   a  of the second groove  17 . That is, the curved convex surface of the retained frame portion  9  is in slidable contact with the curved concave surface of the second groove  17 . This allows change in the angle at which the tablet PC  50  stands on the chassis  11 , or the inclination angle of the display  51  of the tablet PC  50 , for example, by changing the inclination angle of the support plate  4   a  to thereby slide (rotate) the outer surface portion  9   a  on the groove base surface  17   a.    
     Also, as the one edge  50   a  of the outer circumferential portion of the tablet PC  50  is retained in the first groove  16 , placement of the tablet PC  50  in the groove portion  15  so as to be in the standing posture can readily have the terminal group  13  of the first groove  16  in contact with the tablet terminal group on the one edge  50   a  of the tablet PC  50 . This enables direct and stable connection between the terminal group  13  of the second protective cover  3  and the tablet terminal group while keeping a small projecting length of the terminal group  13  of the second protective cover  3 . That is, a wired electrical connection can be readily established between the tablet PC  50  and the input unit (the input device)  12  while keeping a good appearance. As the tablet PC  50  is connected to the input unit  12  via a wire, rather than wireless, an input operation relative to the keyboard (the input unit)  12  is not transmitted to the tablet PC  50  in a mode of the electronic apparatus  10  in which the input device is not used, such as, when the electronic apparatus  10  is folded, for example. This can prevent unintended erroneous input or the like. 
     Specifically, in the case where the tablet PC  50  is wirelessly electrically connected to the input unit  12 , for example, via Bluetooth (registered trademark), different from this embodiment, there is a possibility that the connection be crossed among users in use of the electronic apparatus  10  for an educational purpose or the like in which a plurality of users is present in the same area. Moreover, various sensors or the like to determine whether the mode of the electronic apparatus  10  is in a state with an input device used or a state with an input device not used are necessary in order to prevent unintended erroneous input, which makes the structure completed. Meanwhile, according to this embodiment, it is possible to establish a stable electrical connection between the tablet PC  50  and an input device with a simple structure. 
     Also, in this embodiment, as the groove width of the second groove  17  is wider than that of the first groove  16 , it is possible to ensure that the retained frame portion  9  has a certain amount of thickness to prevent damage to the tablet PC  50  due to an impact or the like, and also to have the retained frame portion  9  stably retained in the second groove  17 . 
     Also, in this embodiment, as the groove depth of the second groove  17  is deeper than that of the first groove  16 , it is possible to ensure that the retained frame portion  9  has a certain amount of thickness to prevent damage to the tablet PC  50  due to an impact or the like, and also to have the retained frame portion  9  stably retained in the second groove  17 . 
     Also, in this embodiment, as the curvature radius of the groove base surface  17   a  of the second groove  17  is larger than that of the base surface  16   a  of the first groove  16  in a cross sectional view perpendicular to the extending direction, it is easy to make the groove width and depth of the second groove  17  wider and deeper than those of the first groove  16 . Thus, it is possible to ensure that the retained frame portion  9  has a certain amount of thickness to prevent damage to the tablet PC  50  due to an impact or the like, and also to have the retained frame portion  9  stably retained in the second groove  17 . 
     Also, in this embodiment, as the blocking wall  17   c  blocks the outside end portion of the second groove  17  in the extending direction, it is possible to have the groove portion  15  not exposed on the outer surface (the lateral surface  11   c ) in a side view when viewed in the extending direction of the chassis  11  so that a good appearance of the chassis  11  can be maintained, while the groove portion  15  is provided on the front surface of the chassis  11 . Also, movement of the retained frame portion  9  retained in the second groove  17  in the extending direction can be prevented also with the blocking wall  17   c.    
     Also, in this embodiment, as the length of the first groove  16  in the extending direction is longer than that of the second groove  17  in the extending direction, the retaining state between the first groove  16  and the one edge  50   a  of the tablet PC  50  is further stabilized. Also, this increases the degree of freedom in laying out the terminal group  13  to be disposed in the first groove  16 , which makes it possible to readily accommodate various tablets PC  50 . 
     Also, in this embodiment, as the groove portion  15  is disposed over the entire length of the front surface of the chassis  11  in the extending direction, a large retaining area can be ensured between the one edge  50   a  of the outer circumferential portion of the tablet PC  50  and the pair of retained frame portions  9  and the groove portion  15 . This can further stabilize the standing posture of the tablet PC  50 . 
     Also, in this embodiment, as the terminals  13   a  included in the terminal group  13  of the second protective cover  3  are so-called pogo pins that retractably project from the base surface  16   a  of the first groove  16 , a preferable state of contact can be maintained between the terminal group  13  of the second protective cover  3  and the tablet terminal group, for example, even when the inclination angle of the display  51  of the tablet PC  50  is adjusted. 
     Also, in this embodiment, as the plurality of terminals  13   a  included in the terminal group  13  is disposed aligned in the extending direction in the first groove  16 , it is possible to readily accommodate the specifications of various tablets PC  50  and input devices. Also, compared with a case in which, for example, a plurality of terminals  13   a  is aligned in the groove width direction in the first groove  16 , different from this embodiment, according to this embodiment, the terminal group  13  can be readily disposed, and deficiency such as failed connection of the terminal group  13  due to an inappropriate inclination angle of the display  51  of the tablet PC  50  is unlikely caused. 
     In this embodiment, as the connection unit  4  includes the support plate  4   a  supporting the tablet PC  50  and the first protective cover  2  and the flexible sheet  4   b  connecting the support plate  4   a  and the second protective cover  3 , it is possible to protect the surface directed opposite from the display  51  of the tablet PC  50  in the folded state, that is, the rear surface, not only with the rear plate  5  of the first protective cover  2  but also with the support plate  4   a . In the folded state, the flexible sheet  4   b  deforms like the spine portion of a book whereby the one edge  50   a  of the outer circumferential portion of the tablet PC  50  and one edge (the lateral surface  11   c ) of the outer circumferential portion of the chassis  11  can be protected. 
     Also, in this embodiment, the terminals  13  include a terminal  13   a  to feed power from the tablet PC  50  to the keyboard  12  and a terminal  13   a  to output an input signal from the keyboard  12  to the tablet PC  50 . That is, the terminals  13   a  having respective functions are gathered in the terminal group  13 , and any terminal group other than the terminal group  13  is unnecessary to be provided. This enables ready establishment of a stable electrical connection between the tablet PC  50  and the input unit  12  in this embodiment. 
     Note that the present invention is not limited to the above-described embodiment, and the structures can be modified or the like within a range not departing from the gist of the present invention, as to be described below, for example. 
     In the above-described embodiment, a case in which the input unit  12  of the second protective cover  3  is the keyboard  12  is described as a non-exclusive example. The input unit  12  may be a highly accurate touch pad (precision touch pad, or PTP) or the like. 
     In the above-described embodiment, a case in which the chassis  11  has a single groove portion  15  on the front surface of the chassis  11 , that is, the first cover  11   a , is described as a non-exclusive example. Like the modified example illustrated in  FIG. 23 , the chassis  11  may have a plurality of, for example, two, three, or four, groove portions  15  on the front surface of the chassis  11 . The plurality of groove portions  15  is disposed aligned in the front-rear direction (the Y axial direction). 
     In this case, the inclination angle of the display  51  can be arbitrarily selected from a plurality of angles when the tablet PC  50  is in the standing state. 
     Other than the above, the respective structures (structural components) described in the above-described embodiment, modified examples, and notes, or the like, can be combined within a range not departing from the gist of the present invention, and addition, omission, replacement, and any other modifications of a structure is possible. The present invention is not restricted by the above-described embodiment or the like, but restricted only by the scope of the claims.