Portable electronic device

An electronic device (1) has hold parts (1R, 1L) constituting respective right and left side parts of the electronic device 1 and being available to be held by a user. Operating sticks (3R, 3L) are provided on the respective hold parts (1R, 1L). A rear touch panel (21) is provided on the rear surface of the electronic device (1). The rear touch panel (21) is provided in at least an area located further upward than a positions P opposite from the operation sticks (3R, 3L). This layout of the rear touch panel (21) allows a user to smoothly operate the rear touch panel (21) while holding the hold parts of the electronic device.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese application JP2011-013470 filed on Jan. 25, 2011, the content of which is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a portable electronic device, and in particular, to a technique for improving operability thereof.

2. Description of the Related Art

U.S. Patent Application Publication 2007/0202956 discloses a portable electronic device (specifically, a game device) which a user can operate while holding right and left side parts thereof. According to this type of electronic device, operative members such as an operation button and an operative stick are arranged to the left and right of a display area defined on the front surface.

SUMMARY OF THE INVENTION

In recent years, along with development of application software, electronic devices have come to be used for diversified purposes. Accordingly, the manners of operations to an electronic device has been required to be diversified. For example, some portable electronic devices have a touch panel on the front surface thereof.

According to one aspect of the present invention, a portable electronic device, includes a front surface having a display area; a hold part positioned to either right or left of the display area, constituting a right or left part of the electronic device, and being available to be held by a user; an operative member provided on the hold part and positioned on the front surface of the electronic device; and a rear touch panel provided on a rear surface of the electronic device. The rear touch panel is provided in at least an area located further upward than an opposite position from the operative member.

According to the above aspect of the present invention, a user can smoothly operate a rear touch panel with his/her finger placed on the rear surface of the electronic device, while holding the hold part of the electronic device to operate an operative member.

DETAILED DESCRIPTION OF THE INVENTION

In the following, one embodiment of the present invention will be described with reference to the accompanying drawings.FIG. 1is a perspective view of a portable electronic device1according to an embodiment of the present invention, showing the front surface of the electronic device1viewed diagonally.FIG. 2is a front view of the electronic device1.FIG. 3is a perspective view of the electronic device1, showing the rear surface of the electronic device1viewed diagonally.FIG. 4is a rearview of the electronic device1.FIG. 5is a bottom view of the electronic device1.FIG. 6is a top view of the electronic device1.FIG. 7is a right side view of the electronic device1.FIG. 8is a left side view of the electronic device1.FIGS. 9 and 10are diagrams illustrating one manner of holding the electronic device1by a user. Specifically,FIG. 9shows the front surface of the electronic device1held by a user, andFIG. 10shows the rear surface of the electronic device1held by a user.

In the following description, the direction indicated by X1-X2is defined as a left-right direction in these diagrams, the direction indicated by Y1-Y2is defined as an up-down direction. Further, a lower side (lower, below) of the electronic device1refers to the side toward a user holding the electronic device1, and an upper side (upper, above) of the electronic device1refers to the opposite side from the lower side.

The electronic device1is, e.g., a game device, a personal digital assistant (PDA), and so forth. The electronic device1has a sound reproducing function, a motion picture reproducing function, a radio or wired communication function or the like. As shown inFIGS. 1 and 2, the electronic device1has a substantially rectangular display area2provided on and positioned in a substantially center of the front surface thereof. The electronic device1has hold parts1R,1L formed to the left and right of the display area2, respectively, which a user can hold with his/her hands. According to one manner in using the electronic device1, a user sandwiches the hold parts1R,1L with his/her thumbs and middle fingers or the like, to thereby hold the electronic device1(seeFIGS. 9 and 10).

The electronic device1has a shape that is long in the left-right direction. As shown inFIG. 2, the left and right edges of the electronic device1(that is, the edges of the hold parts1R,1L) has a substantially semi-circular shape in the front view of the electronic device1, and thus the electronic device1has a curved right side surface11R and a curved left side surface11L. That is, the electronic device1has a substantially round shape that is long in the left-right direction in the front view thereof.

As shown inFIGS. 9 and 10, in many cases, a user places his/her index fingers along the right side surface (the right side surface of the front housing11to be described later)11R and the left side surface (the left side surface of the front housing11)11L of the same. Note that a rear touch panel21is provided on the rear surface of the electronic device1(seeFIG. 4), as to be described later. The fingers placed along the side surfaces11R,11L are moderately bent as the right side surface11R and the left side surface11L of the electronic device1are curved. Consequently, a user can more readily operate the rear touch panel21with his/her finger (e.g., the middle finger) placed on the rear surface, while holding the hold parts1R,1L, compared to a case in which the right side surface11R and the left side surface11L are flat surfaces extending in the up-down direction. That is, a user can readily remove his/her finger rightward or leftward from the touch panel21, and also extend his/her finger to touch the rear touch panel21.

The display area2is provided with a display device and a touch panel (a panel-like position input device) arranged on the display device. The display device is, e.g., a liquid crystal display device, a plasma display device, an organic EL display device, a field emission display device, or the like. The touch panel is, e.g., an electrostatic capacity-type touch panel. In this example, a front cover panel10is attached on the outermost surface of the touch panel, covering the substantially entire front surface of the electronic device1. The display area2defined in the front cover panel10is flush with the area surrounding the display area2(that is, no step is formed in the boundary between the display area2and the surrounding area). In use of the electronic device1, a game image, a motion image, a static image (e.g., a photograph, a pattern, a menu image showing a list of items selectable by a user), and so forth are shown in the display area2. A user can select a desired item and move an object shown in the game image by touching the display area2with his/her finger. Note that the touch panel is not limited to an electrostatic capacity type, and may be, e.g., a resistive film type instead.

The electronic device1includes a housing accommodating a battery (not shown), a circuit board (not shown) where a CPU (Central Processing Unit) or the like is mounted. As shown inFIG. 7, the housing in this example includes a front housing11and a rear housing12. The front housing11is like a box with the rear surface thereof open. The rear housing12is like a box with the front surface thereof open. The front housing11covers the front side of the rear housing12, and is fixed to the rear housing12. In this example, the front housing11and the rear housing12are fixed to each other using a plurality of screws17provided on the outer circumferential part thereof (seeFIG. 4). The above described circuit board or the like is placed in the space enclosed by the front housing11and the rear housing12. The housings11,12are made of, e.g., resin.

As shown inFIG. 2, the front cover panel10constituting the front surface of the electronic device1has an external shape substantially identical to that of the electronic device1, and is attached on the front surface of the front housing11. The display device and the touch panel provided to the display area2are arranged on the rear side of the front cover panel10. For example, an opening corresponding to the display area2is formed on the front housing11, and the display device and the touch panel is placed in the opening of the front housing11.

As shown inFIGS. 1 and 2, the electronic device1includes a plurality of operative members provided on the hold parts1R,1L, projecting from the front surface of the electronic device1and available to operation by a user. Specifically, the electronic device1in this example includes an operative stick3R provided on the right hold part1R and an operative stick3L provided on the left hold part1L as the operative members defined in claims. The operative sticks3R,3L are positioned on and projecting from the front surface of the electronic device1(more specifically, the surface of the front cover panel10) (seeFIGS. 7 and 8). The heads of the operative sticks3R,3L are formed into disk shape, and each operative stick3R,3L has a bar (stem) extending from the head thereof toward inside of the electronic device1. The stem of each operative stick3R,3L is projecting forward from the front surface of the electronic device1. Each operative stick3R,3L can be inclined in the radius directions around the stem. In other words, each operative stick3R,3L can be inclined toward every position in the circumferential direction around the stem. In another embodiment for use, each operative stick3R,3L can rotate in the circumferential direction around the stem, while remaining inclined. Each operative stick3R,3L is an analogue stick, and therefore outputs a signal according to the direction in which the operative stick3R,3L is inclined and the angle of inclination. Note that, however, the movement of the operative sticks3R,3L is not limited to the above described movements, and the operative sticks3R,3L may be supported slidable in the radius directions.

As shown inFIG. 2, buttons4R are further provided on the right hold part1R. The buttons4R are positioned on the front surface of the electronic device1. The buttons4R include a plurality of (specifically four) buttons4a,4b,4c, and4d, which are positioned on the respective ends of a cross shape. The buttons4a,4b,4c,4dare projecting from the front surface of the electronic device1(seeFIG. 7). In addition, a directive key4L is provided on the left hold part1L. The directive key4L has a plurality of (specifically four) convex portions that together constitute a cross shape as a whole. The directive key4L as well is positioned on the front surface of the electronic device1. The convex portions constituting the directive key4L are projecting from the front surface of the electronic device1(seeFIG. 8). Openings10R,10L are formed on the respective right and left parts of the front cover panel10. The opening10R is formed such that the inner edge thereof surrounds the area where the operative stick3R and the buttons4R are located, and similarly, the opening10L is formed such that the inner edge thereof surrounds the area where the operative stick3L and the directive key4L are located.

As shown inFIG. 2, the buttons4R and the directive key4L are positioned more upper and more outward in the left-right direction than the operative sticks3R,3L, respectively. That is, the center position among the buttons4R is positioned more rightward than the right operative stick3R. The center position among the directive key4L is positioned more leftward than the left operative stick3L.

As shown inFIG. 9, in many cases, a user places his/her thumbs on the operative sticks3R,3L and middle fingers or the like on the rear surface of the electronic device1(the rear surfaces of the hold parts1R,1L) to thereby hold the hold parts1R,1L. Then, in using the electronic device1, a user moves his/her thumb diagonally toward the buttons4R or the directive key4L when necessary. Because the buttons4R and the directive key4L are positioned diagonally from the operative sticks3R,3L, a user can readily move his/her thumbs toward the buttons4R and the directive key4L.

As shown inFIG. 2, the positions of the operative sticks3R,3L, the buttons4R, and the directive key4L are offset upward as a whole on the front surface of the electronic device1. That is, the distance from the center of each operative stick3R,3L to the lower edge of the front surface of the electronic device1is larger than the distance from the center of the buttons4R or the directive key4L to the upper edge of the front surface of the electronic device1. Therefore, the center of gravity of the electronic device1is positioned closer to a user, compared to an arrangement in which the operative sticks3R,3L, the buttons4R, and the directive key4L are offset downward, and which enables a user to stably holding the electronic device1.

As shown inFIG. 1or2, a plurality of (three in this example) buttons6a,6b,6care further provided on the front surface of the electronic device1. The buttons6a,6b,6care less used during executing an application software in the electronic device1(e.g., during playing a game), compared to the above described operative sticks3R,3L, the buttons4R, and the directive key4L. The button6ais, e.g., a home button for returning an image shown in the display area2to the initial image. The buttons6b,6care, e.g., a select button for selecting an item shown in the display area2, a start button for starting execution of an application software, and so forth. The buttons6a,6b, and6cmay have a built-in light emitting element such as an LED (light emitting diode) or the like. A light emitting element may be used to report a user about a status of the electronic device1(power on/off, receiving data via a radio communication function).

As shown inFIG. 2, the buttons6a,6b,6care positioned below the operative sticks3R,3L. In detail, the button6ais positioned below the operative stick3L, while the buttons6b,6care positioned below the operative stick3R, being arranged side by side in the left-right direction. The surface of the buttons6a,6b,6care lower in height from the front surface than the top surface (upper end) of the operative sticks3R,3L. This arrangement can prevent erroneous touching the buttons6a,6b,6cby a user s finger while the user is operating the respective operative stick3R,3L. In this example, the surfaces of the buttons6a,6b,6care flush with the front surface (the surface of the front cover panel10) of the electronic device1.

As shown inFIG. 2, the above described buttons provided on the front surface of the electronic device1are all positioned in an area other than the upper side area and the lower side area of the display area2. Specifically, in this example, the operative sticks3R,3L, the buttons4R, and the directive key4L are positioned to the right or left of the display area2. The left button6ais positioned away to the left of the display area2. The button6b,6care positioned away to the right of the right edge of the display area2. With this positioning, a user can prevented from erroneously touching any button provided on the front surface with his/her finger when moving the finger up and down on the display area2(e.g., when scrolling an image).

As shown inFIG. 2, a flat surface (that is, a surface without a concave or a convex, hereinafter referred to as an upper flat surface)10acontinuing from the surface of the area of the display area2is formed further upward than the area where the display area2is located. Moreover, a flat surface (that is, a surface without a concave or a convex, hereinafter referred to as a lower flat surface)10bcontinuing from the front surface of the area of the display area2is formed further downward than the area where the display area2is located. The upper flat surface10aand the lower flat surface10benable a user to smoothly move his/her finger up and down on the display area2. Note that the upper flat surface10aand the lower flat surface10breach the upper and lower edges of the front surface of the electronic device1, respectively, and have a larger left-right width than that of the display area2.

As shown inFIGS. 7 and 8, the upper flat surface10aincludes a slop surface10cin the uppermost part thereof. Specifically, the slop surface10cextends upward being inclined toward the front, so that the upper edge of the slop surface10cis flush with the edge of the upper surface11cof the electronic device1. Similarly, the lower flat surface10bincludes a slop surface10din the lowermost part thereof. The slope surface10dextends downward being inclined toward the front, so that the lower edge of the slop surface10dis flush with the edge of the lower surface11bof the electronic device1. This structure prevents a finger moving largely up and down on the display area2from being caught on the edge of the electronic device1.

As shown inFIG. 2, a camera7is provided on the front surface of the electronic device1. The camera7is used, e.g., to capture an image of a user holding the electronic device1. The position of the camera7is offset toward one side relative to the center line in the left-right direction of the electronic device1. In this example, the camera7is positioned on the hold part1R. This arrangement can reduce movement of the camera7when a user holds the hold part1R. Further, the camera7is positioned avoiding the display area2and the upper area (the upper flat surface10a) and the lower area (the lower flat surface10b) than the display area2. This can prevent the surface of the camera7from getting dirt. Note that the camera7may be positioned on the hold part1L.

As shown inFIG. 2, speakers9R,9L are provided to the front side of the electronic device1. The speakers9R,9L are arranged on the rear side of the front cover panel10. A plurality of holes are formed on the front cover panel10in positions corresponding to the respective speaker9R,9L so that sound can be output through the holes. The speakers9R,9L are positioned avoiding the display area2and the upper area (the upper flat surface10a) and the lower area (the lower flat surface10b) than the display area2. This can prevent the holes formed on the speakers9R9L from getting dirt.

The speakers9R,9L are positioned further outward in the left-right direction than the operative sticks3R,3L, respectively. That is, the right side speaker9R is positioned to the right of the operative stick3R. The left side speaker9L is positioned to the left of the operative stick3L. Because each operative stick3R,3L projects from the front surface of the electronic device1, clearance is ensured between a user s finger placed on the respective operative stick3R,3L and the respective speaker9R,9L. This can prevent the finger from blocking the sound output from the speakers9F9L from spreading.

The electronic device1has a rear surface, which is an opposite surface from the front surface thereof. As shown inFIGS. 3 and 4, a rear touch panel21(touch pad), that is, panel-like position input device, is provided on the rear surface of the electronic device1. The broken line E inFIG. 4outlines the outer shape of the rear touch panel21. As outlined by the broken line E, the rear touch panel21is substantially rectangular.

In this example, a rear cover panel13that is larger in size than the rear touch panel21is placed on the outermost surface of the rear touch panel21, and the surface of the area of the rear touch panel21is flush with the area surrounding the rear touch panel21. Moreover, a hard coat layer is formed on the entire surface of the rear cover panel13. As shown inFIG. 3or4, the outer shape of the rear cover panel13corresponds to the shape of the area inside the curved surfaces (surfaces with numerals12L,12R,12c,12d) formed on the outer circumferential part of the rear surface of the electronic device1. Specifically, the rear cover panel13has a substantially ellipse shape that is long in the left-right direction. The rear cover panel13is attached on the outer surface of the rear housing12. The touch panel21is arranged on the inner surface of the rear cover panel13. For example, an opening is formed on the rear housing12, and the rear touch panel21is placed in the opening of the rear housing12. Note that, the size of the rear cover panel13is not limited to the above described size, and may be a size corresponding to the detection area of the rear touch panel21. Further, the rear touch panel21is not limited to an electrostatic capacity type, but various types are usable. For example, the rear touch panel21may be of a resistive film type.

The rear touch panel21can be used, e.g., as described below. A user may move his/her finger on the rear touch panel21to thereby scroll an image shown on the display area2(seeFIG. 10). Further, a user may touch, e.g., a point on the rear touch panel21to thereby select or move an object shown at the position on the display area2corresponding to the point.

As shown inFIG. 4, the rear touch panel21is located in an area (an area outlined by the broken line E) closer to the center in the left-right direction than the positions on the rear surface opposite from the operative sticks3R,3L (hereinafter referred to as a stick position P). Specifically, in this example, the rear touch panel21is positioned closer to the center in the left-right direction than the hold parts1R,1L, that is, located in the area between the left and right hold parts1R,1L. This arrangement prevents a user from erroneously touching the rear surface panel21with his/her finger, while holding the hold parts1R,1L (that is, while the user s middle finger is placed on the rear surface of the hold parts1R,1L) (seeFIG. 10). In this example, the rear touch panel21is positioned between the opposite position from the buttons4R and the opposite position from the directive key4L.

As shown inFIG. 4, the rear touch panel21is provided in an area located further upward than the stick position P. In most of the time, a user places his/her thumbs on the operative sticks3R,3L and his/her middle fingers or the like on the rear surface, to thereby hold the hold parts1R,1L, as described above (seeFIGS. 9 and 10). When the user extends his/her middle finger or the like while holding the hold parts1R,1L, the user s finger is naturally positioned further upward than the stick position P. In this embodiment, because the rear touch panel21is located further upward than the stick position p, the user can readily operate the rear touch panel21with his/her middle finger, while holding the hold parts1R,1L.

In this example, a button14R is provided at the rightmost position of the top surface11c, and a button14L is provided at the leftmost position of the top surface11cAccordingly, a user generally rests his/her thumbs on the respective operative sticks3R,3L, and his/her index fingers at the corners (that is, on the buttons14R,14L in this example) of the electronic device1so that the user can immediately press the buttons14R,14L when necessary. Depending on the application software carried out in the electronic device1, this positioning may be a basic manner of holding the electronic device1. The area of the rear touch panel21is designed such that a user holding the electronic device1in this manner can operate the rear touch panel21with his/her middle finger. Specifically, as shown inFIG. 4, the distance D3from the straight line Y in the up-down direction passing the center of the stick position P and the respective button14R,14L to the respective left/right edge of the rear touch panel21is shorter than the distance D4from the straight line Y to the respective left/right edge of the electronic device1. This is, the right and left edge of the touch panel21is comparatively close to the stick position P. Moreover, the upper edge of the rear touch panel21is positioned further upward than the center between the stick position P and the buttons14R,14L. That is, the upper edge of the touch panel21is comparatively close to the buttons14R,14L. According to this arrangement, a user can easily touch the rear touch panel21with his/her middle finger while holding the electronic device1in the above described basic manner.

As to be described later, the buttons14R,14L in this example can become concaved, that is, move downward, relative to the top surface11c. The rear touch panel21is positioned from the buttons14R,14L in a diagonally downward direction, and therefore a user can touch the rear touch panel21with the index fingers when moving diagonally the index finger on the buttons14R,14L in a press direction.

In this example, the rear touch panel21is offset upward relative to the stick position P. That is, the rear touch panel21is located in an area expanding from the line L, which is a line extending in the left-right direction and passing the stick positions P, toward the upper edge of the rear surface. As a result, the center C1in the up-down direction of the rear touch panel21is positioned further upward than the line L. With this arrangement of the rear touch panel21, a user is not required to extend his/her finger placed on the rear surface downward. Accordingly, a user can stably hold the electronic device1even when using the touch panel21. Note that the lower edge of the rear touch panel21is positioned slightly lower than the line L.

Note that, the area where the rear touch panel21is located is not limited to the above described area, and the area may expand largely from the line L toward the lower edge of the rear surface. That is, it is fine that the rear touch panel21is provided in at least an area located further upward than the stick position P.

As shown inFIG. 4, as the area where the rear touch panel21is located is offset toward one side in the up-down direction relative to the center C2in the up-down direction of the electronic device1. That is, the center C1in the up-down direction of the rear touch panel21is positioned further upward than the center C2. Thus, the distance D1between the lower edge of the rear touch panel21and the lower surface11bof the electronic device1is longer than the distance D2between the upper edge of the rear touch panel21and the upper surface11cof the electronic device1. In other words, the center C2in the up-down direction of the electronic device1is positioned further lower than the center C1in the up-down direction of the rear touch panel21. Therefore, an area without the rear touch panel21is ensured in a lower part of the rear surface of the electronic device1. The up-down width of the lower part area is larger than that of the area located further upward than the upper edge of the rear touch panel21. This arrangement of the rear touch panel21can utilize the lower part of the electronic device1for arranging electronic components inside the electronic device1.

As shown inFIG. 3or4, a flat surface (hereinafter referred to as a lower flat surface23a) is formed in an area lower than the rear touch panel21. The lower flat surface23adefines the substantially same plane as the surface of the area of the rear touch panel21(the surface of the rear cover panel13). No projecting operative member (e.g., a button) is provided on the lower flat surface23a. This formation enables a user to largely move his/her finger up and down on the rear touch panel21. The lower flat surface23aexpands from the lower edge of the area of the rear touch panel21to the lowermost part of the rear surface of the electronic device1, and has a left-right width substantially identical to that of the rear touch panel21.

In one example of the electronic device1, a part of the surface of the rear cover panel13functions as the lower flat surface23a. In another example, a plate where various information (product name or the like) about the electronic device1are described may be attached in the area lower than the rear touch panel21, and the surface of the plate may function as the lower flat surface23a. That is, the surface of the plate and that of the area of the rear touch panel21may constitute the same plane.

The width of the rear touch panel21is smaller than that of the display area2. As a result, the degree of freedom in laying out components arranged in the electronic device1can be increased, while ensuring a sufficient size for the display area2. For example, the electronic device1includes a plurality of antennas for radio communication. The configuration where the rear touch panel21has a smaller width than the display area2facilitates an arrangement where the antennas are arranged away from both of the rear touch panel21and the touch panel constituting the display area2. Specifically, the antennas can be readily arranged in positions not overlapping the rear touch panel21in the thickness direction (the direction indicated by Z1-Z2inFIGS. 7 and 8) of the electronic device1, while ensuring a sufficient distance between the antenna and the display area2. This can improve stability in communication through the antenna.

In this example, as shown inFIGS. 2 and 4, the up-down width of the rear touch panel21is smaller than that of the display area2, and the rear touch panel21is offset upward relative to the display area2. That is, the center C1in the up-down direction of the rear touch panel21is positioned further upward than the center in the up-down direction of the display area2. Therefore, a component such as an antenna or the like can be accommodated in the lower part of the electronic device1.

Meanwhile, the left-right width of the rear touch panel21is substantially equal to that of the display area2. With this design, the distance between the left/right edge of the electronic device1and the rear touch panel21can be prevented from becoming large. As described above, the up-down width of the rear touch panel21is smaller than that of the display area2, and the left-right width of the rear touch panel21is equal to that of the display area2. As a result, layout of components in the electronic device1can be facilitated, and operability of the rear touch panel21can be prevented from being deteriorated.

The relationship between the width of the rear touch panel21and that of the display area2is not limited to the above. For example, the left-right width of the rear touch panel21may be larger than that of the display area2. As a result, the left and right edges of the rear touch panel21are positioned closer to the respective hold parts1R,1L, which consequently improves operability of the rear touch panel21. To the contrary, the left-right width of the rear touch panel21may be smaller than that of the display area2. This arrangement facilitates laying out of a component to be arranged inside the hold parts1R,1L.

As shown inFIGS. 3 and 4, the electronic device1has a guide12fformed on the rear surface thereof for guiding the area of the rear touch panel21. The guide12fis positioned to the right and left of the rear touch panel21. In other words, the guide12fis formed on the respective rear surfaces of the hold parts1R,1L. A user can recognize the area of the rear touch panel21by touching the guide12fwith his/her finger.

The rear touch panel21(the surface of the rear cover panel13) has a flat surface. The surface of the guide12fhas a style different from the surface of the rear touch panel21. For example, a concave portion and a convex portion are formed on the guide12f. In detail, the entire guide12fmay be concave or convex, or a plurality of concave portions and convex portions may be formed on the guide12f. Yet alternatively, the guide12fmay have a surface rougher than the rear touch panel21. Further alternatively, the guide12fmay be made of a material different from that of the surface of the rear touch panel21.

FIG. 11is a cross sectional view of the guide12fto be described below of the electronic device1, showing a cross section along the line XI-XI inFIG. 4. As shown inFIG. 11, the rear surface of the electronic device1is concaved in the guide12fin this example. Accordingly, a user may readily rest his/her finger on the guide12fwhen not using the rear touch panel21. The guide12fis surrounded by a flat surface13bconstituting the same plane as the surface of the rear touch panel21.

As shown inFIG. 4, the rear touch panel21is surrounded by a groove13gformed along the outer edge thereof. In this example, the groove13gis formed along the upper, left, and right edges of the rear touch panel21. The groove13gas well can have a function of guiding a user the area of the rear touch panel21.

As shown inFIG. 4, the guide12fis offset downward relative to the rear touch panel21. That is, the center in the up-down direction of the guide12fis positioned further lower than the center C1of the rear touch panel21. The lower end of the guide12fis positioned lower than the lower edge of the rear touch panel21. Accordingly, the tip end of a middle finger placed on the rear surface can be more readily placed on the guide12f. The guide12fin this example is formed having a substantial oval shape that is long in the up-down direction, with the up-down width thereof substantially corresponding to that of the rear touch panel21.

As shown inFIG. 11, the rear surface of the electronic device1includes a slope12hformed between the deepest position P1of the guide12fand the edge12gof the guide12ftoward the rear touch panel21. With this structure a finger resting on the guide12fcan be readily moved toward the rear touch panel21. In this example, the surface of the guide12fis curved in a cross section thereof. Specifically, the cross section of the guide12fpresents an arc shape open rearward of the electronic device1. The slope12hconstitutes a part of the curved surface.

As shown inFIG. 4, a space is ensured between the guide12fand the left/right edge of the area where the rear touch panel21is located. That is, the edge12gof the guide12ftoward the rear touch panel21is positioned away from the left/right edge of the rear touch panel21. This structure can prevent a finger resting on the guide12ffrom erroneously touching the rear touch panel21.

Further, the surface of the guide12fis made of a material different from the material forming the surface of the area of the rear touch panel21. In this example, as shown inFIG. 11, the guide12fis integrally formed with the rear housing12. The rear cover panel13has an opening formed in a position corresponding to the guide12f, and a part of the rear housing12is exposed in the opening. The exposed part constitutes the guide12f. Meanwhile, the flat surface13bsurrounding the guide12fis formed by the rear cover panel13.

As shown inFIGS. 3 and 4, the rear cover panel13is slightly smaller in size than the rear housing12in the rear view of the electronic device1. Specifically, in this example, the up-down width of the rear cover panel13is smaller than that of the rear housing12, and consequently, the uppermost part12cof the rear housing12is positioned further upward than the upper edge of the rear cover panel13. As shown inFIG. 7or8, a step K is formed between the edge of the uppermost part12cof the rear housing12and the upper edge of the rear cover panel13. In other words, the surface of the rear cover panel13is positioned slightly rearward than the edge of the uppermost part12cof the rear housing12. With this structure, a user can recognize the area of the rear touch panel21by touching the step K when moving his/her finger from the uppermost part12ctoward the rear touch panel21.

In this example, as shown inFIG. 4, the left-right width of the rear cover panel13is smaller than that of the rear housing12. Therefore, the outer circumferential part of the rear housing12surrounds the rear cover panel13. The step K is formed between the outer circumferential part of the rear housing12and the outer circumferential edge of the rear cover panel13.

As shown inFIGS. 1,5, and6, the leftmost part12L and rightmost part12R of the rear surface of the electronic device1are curved. That is, the rear surface has a curved surface located in the leftmost part12R and the rightmost part12L and curved toward the front surface of the electronic device1. The curved surface of the leftmost part12L is curved such that it becomes closer to the front surface of the electronic device1as it goes leftward. Similarly, the curved surface of the rightmost part12R is curved such that it becomes closer to the front surface of the electronic device1as it goes rightward. With this structure, a user can more readily support the rear surface of the electronic device1, compared to a structure in which each of the rightmost part12R and the leftmost part12L has a sharp angle.

As shown inFIG. 7, the uppermost part12cof the rear surface as well is curved. That is, the rear surface includes a curved surface located in the uppermost part12cand curved toward the front surface of the electronic device1. The curved surface of the uppermost part12cis curved such that it becomes closer to the front surface of the electronic device1as it goes upward. With this structure, a user can smoothly move his/her finger from the upper surface11cof the electronic device1toward the rear touch panel21. In this example, the lowermost part12dof the rear surface as well is curved toward the front surface of the electronic device1.

As described above, the rear surface of the electronic device1includes, in the outer circumferential part thereof, a curved surface curved toward the front surface of the electronic device1. In this example, the curved surface is formed over the entire circumference of the rear surface. The rear touch panel21and the guide12fare positioned in the area enclosed by the outer circumferential part. The curved outer circumferential part is formed by the rear housing12. That is, the rear housing12is formed like a plate of which edge is curved toward the front surface of the electronic device1.

The outer edge of the outer circumferential part of the rear housing12(that is, the uppermost part12c, the lowermost portion12d, the rightmost part12R, and the leftmost part12L) continues to the top surface11c, lower surface lib, right side surface11R, and left side surface11L of the front housing11. As shown inFIG. 5, the height H1of the curved surface formed on the outer circumferential part is slightly larger than the height H2of the upper surface11cor the like. Further, the width W of the curved surface is slightly larger than the height H1of the curved surface.

As shown inFIG. 3or4, a camera24is provided on the rear side of the electronic device1. Specifically, in this example, the camera24is positioned on the uppermost part12cat the center in the left-right direction of the electronic device1. The front surface of the camera24is positioned concaved relative to the rear surface of the electronic device1(the surface of the rear cover panel13). Therefore, when the electronic device1is placed on a surface, the front surface of the camera24is positioned away from the surface (the surface where the electronic device1is placed), so that the front surface of the camera24can be prevented from getting dirt.

A plurality of operative members are provided on the surface forming the outer circumference of the electronic device1(specifically, the right side surface11R, the left side surface11L, the top surface11c, and the lower surface11bof the front housing11, all hereinafter collectively referred to as a circumferential surface). These operative members on the circumferential surface are arranged avoiding the right side surface11R and the left side surface11L. With this arrangement, a user can be prevented from erroneously moving the operative member when holding the hold parts1R,1L. In this example, as shown inFIG. 6, the button8a,8b,8care provided on the top surface11c. The button8ais, e.g., a power button, and the buttons8b,8care, e.g., sound volume buttons.

As shown inFIG. 6, the electronic device1includes covers15a,15bconstituting a part of the upper surface11c. A slot for insertion of a card-type recording medium storing, e.g., a program for a game is formed inside the cover15a. The cover15acovers the slot. Meanwhile, a terminal (e.g., a USB terminal) for connection of an accessory and a peripheral device of the electronic device1is formed inside the cover15b. The cover15bcovers the terminal.

As shown inFIG. 3, the electronic device1includes a cover15cconstituting a part of the curved surface12L. A slot for insertion of a card-type recording medium is formed inside the cover15c. The cover15ccovers the slot.

Terminals16a,16bfor connecting with a terminal of an external device are provided on the circumferential surface of the electronic device1. Specifically, the terminals provided on the circumferential surface are all arranged avoiding the right side surface11R and the left side surface11L. More specifically, as shown inFIG. 5, the terminals16a,16bare provided on the lower surface11b. The terminal16ais a power terminal or a USB terminal for connection of a charge device for charging the battery of the electronic device1. The terminal16bmay be, e.g., a terminal of a headphone or a microphone. A cover15dis provided on the curved surface of the lowermost part12d, and a slot for insertion of a card-type storage medium is formed inside the cover15d. The cover15dcovers the slot. The cover15dis curved and constituting a part of the curved surface of the lowermost part12d.

As shown inFIGS. 1 and 2, the button14R is provided at the rightmost position of the top surface11c(in other words, the uppermost position of the right side surface11R). The button14L is provided at the leftmost position of the same (in other words, the uppermost position of the left side surface11L). As shown inFIG. 9, a user can hook his/her index fingers on the respective buttons14R,14L, while holding the hold parts1R,1L. The buttons14R,14L can move so as to be concaved relative to the top surface11c. That is, the buttons14R,14L can move downward.

As shown inFIG. 2, the top surfaces (a surface pressed by a finger) of the buttons14R,14L are curved in conformity with the right side surface11R and the left side surface11L, respectively. In other words, the top surface of the button14R is flush with the right side surface11R. The edge of the button14R and the right edge of the front housing11together make a substantially semi-circular shape as a whole in the front view of the electronic device1. Similarly, the top surface of the button14L is flush with the left side surface11L, and the edge of the button14L and the left edge of the front housing11together make a substantially semi-circular shape as a whole in the front view of the electronic device1. Therefore, as shown inFIG. 9, a user s index fingers with tip end thereof resting on the respective buttons14R,14L are moderately bent. As a result, a user can readily extend his/her other finger (specifically, the middle finger) placed on the rear surface of the electronic device1toward the rear touch panel21.

As described above, according to the electronic device1, the rear touch panel21is provided in an area located further upward than the positions P opposite from the operation sticks3R,3L provided on the hold parts1R,1L, respectively. This arrangement enables a user to smoothly operate the rear touch panel21, while holding the hold parts1R,1L.

Further, the rear touch panel21is offset upward relative to the operative sticks3R,3L. According to this layout, a user is not required to extend his/her finger placed on the rear surface toward the lower part of the electronic device1, and therefore can stably hold the electronic device1.

Each operative stick3R,3L is movable in the radius directions around the respective operative stick3R,3L. As input of a direction instruction using the operative sticks3R,3L is easy, a user may keep his/her fingers placed on the respective operative sticks3R,3L at most of the time. Therefore, formation of the rear touch panel21in an area above the positions opposite from the respective operative sticks3R,3L allows a user to smoothly operate the rear touch panel21in the more number of scenes for use.

The rear surface of the electronic device1has the guide12ffor guiding a user the area where the rear touch panel21is located. This structure can prevent erroneous touching the rear touch panel21by a user s finger. Note that the guide12fmay be formed on a member that constitutes the rear surface of the electronic device1(e.g., the housing or the cover that constitutes the rear surface of the electronic device1), or a member different from a member constituting the rear surface of the electronic device1may be provided as a guide.

A space is ensured between the guide12fand the area where the rear touch panel21is provided. The space can prevent a user s finger from erroneous touching the rear touch panel21.

The surface of the guide12fhas a style different from that of the surface of the area where the rear touch panel21is located. With this structure, erroneous touching the rear touch panel21by a user s finger can be more reliably prevented.

Further, the rear surface of the electronic device1is concaved in the guide12f. With this structure, a user can rest his/her finger in the concave portion when not intending to use the rear touch panel21, to thereby avoid erroneous touching the rear touch panel21.

The rear surface of the electronic device1has the slope12hbetween the deepest position P1of the guide12fand the edge12gof the guide12ftoward the rear touch panel21. The slope12hcan prevent a user s finger from being caught on the edge12gof the guide12f. Consequently, a user can smoothly extend his/her finger toward the rear touch panel21.

The material constituting the surface of the guide12fdiffers from that of the surface of the area where the rear touch panel21is located. With this structure, erroneous touching the rear touch panel21by a user s finger can be more readily prevented.

The width (the up-down width in the above description) of the rear touch panel21is smaller than that of the display area2. This structure facilitates layout of components (e.g., an antenna) that require a sufficient distance from both of the display area2and the rear touch panel21, while ensuring a sufficient size for the display area2.

The rear touch panel21is offset upward relative to the center C2in the up-down direction of the electronic device1. This arrangement of the rear touch panel21facilitates layout of components arranged inside the electronic device1.

The outer circumferential part of the rear surface of the electronic device1is curved toward the front. With this structure, a user can more readily place his/her finger on the rear surface of the electronic device1.

The rear surface includes a flat surface continuing downward from the surface of the area where the rear touch panel21is located. With this structure, a user can more readily move his/her finger largely in the up-down direction on the rear touch panel21as the finger is not caught on the edge of the rear touch panel21.

The edge of each hold parts1R,1L is curved into a semi-arc shape in the front view of the electronic device1. With this shape of the hold part1R,1L, a user can more readily move his/her finger on the rear surface of the electronic device1, while holding the hold parts1R,1L.

Note that the present invention is not limited to the above described electronic device1, and various modifications are possible.

For example, the present invention may be applied to a portable electronic device (a game device) that includes an upper enclosure and a lower enclosure capable of being opened and closed. In this case, an operative member may be provided on the lower enclosure, and a rear touch panel may be provided on the rear surface of the upper enclosure.

Further, the left and right edges of the electronic device1may not be curved as such. That is, the electronic device1may be formed into a substantial rectangular solid.

Further, although the operative sticks3R,3L are provided to the left and right of the display area2, respectively, in the electronic device1, the operative stick may be provided only to one of the right and left of the display area2.

Further, the rear cover panel13is provided on the outermost surface of the rear touch panel21, and the surface of the area of the rear touch panel21is flush with the area surrounding the touch panel21. However, a step may be formed between the area of the rear touch panel21and the surrounding area.

Further, although the rear touch panel21is offset upward relative to the display area2in the above description, the rear touch panel21may be provided in a position directly opposite from the display area2. Further, although the rear touch panel21is offset upward relative to the electronic device1, the center C1in the up-down direction of the rear touch panel21may coincide with the center C2in the up-down direction of the electronic device1.