Abstract:
Disclosed is a mobile terminal apparatus which includes: an upper housing in which a display portion having a display screen is disposed; a lower housing having an inner major surface in which an operating portion including a plurality of kinds of input keys is disposed; and a connecting portion which connects the upper housing with the lower housing such that the upper housing and the lower housing are turnable away from and toward each other to open and close the apparatus. In this apparatus, the inner major surface of the lower housing is recessed at an area where input keys of a first group that corresponds to a particular one of the kinds is disposed, so as to increase a level difference between a keytop of each of the input keys of the first group and the inner major surface.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS  
       [0001]     The present invention contains subject matter related to Japanese Patent Application No. 2004-377888 filed in the Japanese Patent Office on Dec. 27, 2004, the entire contents of which being incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a mobile terminal apparatus, and more particularly to a structure of a mobile terminal apparatus having an upper housing and a lower housing that are connected to each other such that the upper and lower housings are relatively displaceable away from and toward each other to open and close or fold the mobile terminal apparatus.  
         [0004]     2. Description of the Related Art  
         [0005]     Typically, a mobile terminal apparatus (hereinafter simply referred to as “terminal”) of fold type or clamshell type, such as mobile phone terminal of the type, includes an upper housing, a lower housing, and a hinge portion that connects the upper and lower housings such that the upper and lower housings are turnable about the hinge portion away from and toward each other so that the terminal is openable and closable or foldable. The upper housing has a display screen on an inner major surface thereof, and the lower housing has on an inner major surface thereof an operating portion including various input keys. Fold-type terminals are widely used these days because of their advantages that the screen and key area of the terminals are wide when used, and the terminals are compact when closed to be carried.  
         [0006]     When closed or folded, an operating portion of such a fold-type terminal is opposed to a display screen in the form of a transparent plate. A thickness of the terminal becomes inevitably larger when the terminal is folded than when the terminal is not folded, since the upper housing is superposed on the lower housing in the folded state of the terminal. To minimize the thickness of the terminal as folded, it is desirable to minimize a clearance between the upper and lower housings as superposed on each other, in addition to reduce a thickness of each of the upper and lower housings. However, contact of any of the input keys with the display screen leads to contamination or damage of the display screen. When an input key excessively protrudes from the inner major surface, that input key may be unintentionally pressed upon deformation of one or both of the upper and lower housings, thereby causing a false operation of the terminal.  
         [0007]     In a common remote controller for a television set or an audio system, input keys or manual operation buttons are disposed in a surface of the remote controller to protrude there from to facilitate operation or pressing thereof by a user.  
         [0008]     However, in the fold-type terminal, the keytops of the input keys are substantially flush with the surface in which the input keys are disposed, for the above-described reason. The shape of the keytop of each of the input keys is substantially flat, so as not to form a clearance around each input key. As described above, it is difficult to form the keytop in a rounded shape.  
         [0009]     Usually, to alleviate an impact imposed on the upper and lower housings upon folding of the terminal with a clearance left between the upper and lower housings, a shock-absorbing member such as that of rubber is disposed at an end portion of the inner surface of one or both of the upper and lower housings. Increasing a height of the shock-absorbing member allows the input keys to further protrude from the surface in which the input keys are disposed. However, the clearance between the upper and lower housings while the terminal is folded or closed increases with an increase in the amount of the protrusion, or the height, of the input keys, thereby increasing the thickness of the terminal as folded, while making the terminal prone to introduce dust and dirt into the clearance.  
         [0010]     JP-A-11-112627 discloses a mechanism in a fold-type mobile terminal having an upper housing and a lower housing, which mechanism is configured such that an operating portion thereof is retracted into the lower housing when the upper and lower housings are turned toward each other, that is, the terminal is folded or closed, and the operating portion comes out of the lower housing when the upper and lower housings are turned away from each other, that is, the terminal is opened.  
         [0011]     According to the terminal disclosed in the above-mentioned publication, the usability of the operating portion is enhanced by the mechanism, in exchange for increases in the complexity of the mechanism and the cost of the terminal. Further, although a clearance formed between the upper and lower housings when the terminal is folded can be made relatively small, a space for allowing movement of input keys a direction of a thickness of the lower housing is necessary in the lower housing, and thus it is inevitable that the thickness of the lower housing is relatively large.  
       SUMMARY OF THE INVENTION  
       [0012]     The present invention has been developed in view of the above-described situations. According to one embodiment of the invention, there is provided a mobile terminal apparatus which has an upper housing and a lower housing that are connected to be turnable away from and toward each other so that the apparatus is openable/closable, and is configured to have a reduced thickness when closed, and exhibit an enhanced usability of input keys disposed in one of the upper and lower housings, i.e., an enhanced easiness in manipulating the input keys, without any input key contacting a surface of the other of the upper and lower housings that is opposed to the input keys.  
         [0013]     That is, another embodiment of this invention is directed to a mobile terminal apparatus that includes: an upper housing in which a display portion having a display screen is disposed; a lower housing having an inner major surface in which an operating portion including a plurality of kinds of input keys is disposed; and a connecting portion which connects the upper housing with the lower housing such that the upper housing and the lower housing are turnable away from and toward each other to open and close the apparatus. The inner major surface of the lower housing is recessed at an area where input keys of a first group that corresponds to a particular one of the kinds is disposed, so as to increase a level difference between a keytop of each of the input keys of the first group and the inner major surface.  
         [0014]     By this arrangement, the actual height of the input keys need not be changed in order to increase a level difference between the keytop of the individual input keys and the inner major surface of the lower housing. Thus, it is not necessary to change the absolute height of the input keys itself, thereby preventing an increase in the thickness of the terminal apparatus in the closed or folded state.  
         [0015]     It is preferable that the keytop of each of the input keys of the first group is convex outward.  
         [0016]     By this arrangement, convexity is provided to the input keys so that the user feels the convexity when manipulating the input keys. This facilitates distinguishing among the individual input keys by a finger. The present feature is particularly effective where the input keys are arranged close to one another.  
         [0017]     According to another embodiment of the invention, the mobile terminal apparatus is adapted such that the inner major surface of the lower housing in which the operating portion is disposed is sectioned into a first area in which the input keys of the first group are disposed, and a second area constituted by an area other than the first area in the inner major surface, and input keys of a second group that corresponds to another of the kinds are disposed in the second area and the level of the inner major surface of the lower housing is higher at the second area than at the first area.  
         [0018]     By this arrangement, each of a large number of input keys is disposed in either of the first and second areas that are visually and sensuously distinguishable, depending on the usage of the input key, thereby enhancing the easiness in manipulating the operating portion.  
         [0019]     In the above-described arrangement, a keytop of each of the input keys of the second group is preferably substantially flush with a part of the inner major surface around the input keys of the second group. Preferably, each of the input keys of the second group has a keytop that is substantially flat.  
         [0020]     Preferably, the inner major surface is configured such that two lateral end portions thereof on opposite sides of the first area are located at the same level as the second area.  
         [0021]     According to this arrangement, the two lateral end portions reinforce the mechanical strength of the lower housing as well as prevent the input keys from contacting the display portion.  
         [0022]     The mobile terminal apparatus may further include a shock-absorbing member disposed at an end portion in a surface of at least one of the lower housing and the upper housing, which surface is to be opposed to the other housing when the apparatus is closed. The end portion is remote from the connecting portion.  
         [0023]     The shock-absorbing member functions to absorb an impact of contact between the upper and lower housings upon closing of the terminal apparatus, and to ensure a clearance between the upper and lower housings when the terminal apparatus is closed.  
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0024]     Embodiments of the present invention will be described in detail based on the following figures, wherein:  
         [0025]      FIGS. 1A, 1B ,  1 C,  1 D and  1 E are plan views of a fold-type mobile terminal apparatus according to one embodiment of the invention in a folded or closed state, as seen from the upper side, left side, front side, right side, and lower side, respectively;  
         [0026]      FIG. 2  is a plan view of the apparatus as seen from the back side;  
         [0027]      FIGS. 3A and 3B  are a front side view and a right side view of the apparatus in an open state; and  
         [0028]      FIGS. 4A and 4B  are cross-sectional views respectively taken along line A-A and line B-B in  FIG. 3A . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0029]     Hereinafter, there will be described in detail a fold-type mobile terminal apparatus according to a presently preferred embodiment of the invention, by referring to the accompanying drawings.  
         [0030]      FIGS. 1A-1E  are plan views of the fold-type mobile terminal apparatus in the form of a mobile phone terminal in a folded or closed state, as seen from the upper side, left side, front side, right side, and lower side, respectively.  
         [0031]     As shown in  FIGS. 1A-1E , the present mobile phone terminal has an upper housing  10 , a lower housing  20 , and a connecting portion  14  in the form of a hinge arrangement that connects the upper housing  10  with the lower housing  20  such that the upper and lower housings  10 ,  20  are relatively turnable away from and toward each other to establish an open state and a closed or folded state of the terminal. As shown in  FIG. 1C , a sub display  15 , a picture light  16 , a camera  17 , and an infrared light  18  are disposed in an outer major surface of the upper housing  10 . As well shown in  FIG. 1A , an incoming/charge lamp  13  for indicating arrival of an incoming call or a mail message, as well as a fact that the charging is currently performed, is disposed in the connecting portion  14 . As well shown in  FIG. 1B , an earphone jack  11  and an external output terminal  12  are disposed on a left side of the lower housing  20 . As well  0 shown in  FIG. 1D , a backlight key  21  and a camera mode key  22  are disposed on a right side of the lower housing  20 . Similarly, a macro selector switch  23  for enabling close-up shots of the camera  17  is disposed on a right side of the upper housing  10 .  
         [0032]      FIG. 2  is a back side view of the terminal shown in  FIGS. 1A-1E . That is,  FIG. 2  is a plan view of the terminal in the folded state as seen from the side of a major outer surface of the lower housing  20 . In the vicinity of the connecting portion  14 , there is disposed a speaker  19  for outputting sounds such as ring alert up on arrival of an incoming call or mail message.  
         [0033]      FIGS. 3A and 3B  are a front side view and a right side view of the mobile terminal in the open state. The principle of the embodiment of the invention is best shown in  FIG. 3A . As shown in  FIG. 3B , when the terminal is in a fully open state, an angle of substantially 160 degrees is formed between an inner major surface of the upper housing  10  and an inner major surface of the lower housing  20 , although not limited thereto.  
         [0034]     Referring to  FIG. 3A , a display  32  is disposed substantially at a center of the inner major surface of the upper housing  10 , to extend across most of an area of the inner major surface. As such a display, a liquid crystal display or an organic EL display is typically employed. In the invention, however, any kind of display may be employed as the display  32 . At each of both lateral marginal positions in an upper end portion of the inner major surface of the upper housing  10 , there is disposed a shock-absorbing member  24  constituted by an elastic member such as that of rubber, to protrude from the inner major surface. The shock-absorbing members  24  serve to alleviate an impact imposed on the upper and lower housings  10 ,  20  when the terminal is abruptly folded, and to ensure a minimum clearance between the upper and lower housings  10 ,  20  when the terminal is folded. In the present embodiment, the clearance formed between the upper and lower housings when the terminal is folded is about 0.8 mm, and accordingly a height of each of the shock-absorbing members  24  as measured from the inner major surface of the upper housing is also about 0.8 mm. By this arrangement, the upper and lower housings  10 ,  20  do not directly contact each other in normal use. An ear receiver  31  from which sound is outputted during phone call is disposed at a center (i.e., substantially at a midpoint between the two shock-absorbing members  24 ) in the upper portion of the inner major surface of the upper housing  10 .  
         [0035]     In the vicinity of the connecting portion  14 , there are disposed a center jog  33  as a kind of jog dial, and a left arrow key  34  and a right arrow key  35  on opposite lateral sides of the center jog  33 .  
         [0036]     At a first area in the inner major surface of the lower housing  20 , which is located substantially at a center of the inner major surface, there is disposed alphanumeric keys or tenkey  41  which is included in input keys of a first group. At the entirety of the first area, the inner major surface of the lower housing  20  is slightly recessed from the other area in the inner major surface. That is, the inner major surface of the lower housing  20  has at the first area a portion lowered by about a few tenths of a millimeter to 1 or 2 millimeters. In this embodiment, the depth of the recess or the amount by which the inner major surface is lowered at the first area is substantially 0.3 mm. Each of the input keys disposed in the first area has a keytop surface that is curved to be convex outward, as will fully described later by referring to  FIGS. 4A and 4B .  
         [0037]     As input keys of a second group, a mail key  36 , a web key  37 , a start key  38 , an on/off key  39 , and a clear key  40  are disposed in a second area on the upper side of the first area in the inner major surface of the lower housing  20 . The mail key  36  is manipulated when an electronic mail function is to be activated, the web key  37  is manipulated when a web browser function is to be activated, the start key  38  is manipulated when a telephone call or a communication is to be started, the on/off key  39  is manipulated when the terminal is to be powered on/off, and the clear key  40  is manipulated when an operation is to be cancelled or in like situations. Unlike at the first area, the inner major surface of the lower housing  20  is configured in the same manner as in the past at the second area. That is, a keytop of each of the input keys of the second group is substantially flush with a portion of the inner major surface of the lower housing  20  at the other area, i.e., the area other than the first and second areas. According to the present embodiment, the keytop of each input key of the second group is substantially flat. If the keytop is convex outward, a peripheral portion of the keytop is located at a lower level than the inner major surface to form a gap between a surface of the keytop and the inner major surface, in which gap dust and dirt will accumulate. According to the embodiment, however, such accumulation of dust and dirt is prevented. Nevertheless, the invention does not exclude an arrangement where the keytop of each input key in the second area is rounded or convex outward.  
         [0038]     In the inner major surface, both lateral end portions  45 ,  46  at the sides of the first area are located at the same level as a portion  53  of the inner major surface of the second area. This configuration reinforces a mechanical strength of the lower housing  20 , which is decreased by presence of a recess  44  or the lowered portion substantially at the center of the lower housing  20 . Further, when at least one of the upper housing and the lower housing is deformed by an external pressure, and a degree of the deformation is more than that the upper housing is brought into contact with the lower housing  20  only at the shock-absorbing members  24 , the lateral end portion or portions  45 ,  46  is brought into contact with a corresponding lateral end portion or portions in the upper housing  10 , thereby preventing contact of any input key with the transparent plate of the display screen.  
         [0039]      FIGS. 4A and 4B  are cross-sectional views taken along line A-A and line B-B in  FIG. 3A , respectively. As seen in  FIG. 4A , the inner major surface of the lower housing  20  is lower at the first area than at the second area  53 , to form the recess  44  at the first area. The keytop  51  of each of the input keys in the first area, namely, the alphanumeric keys, is convex outward. The keytop  52  of each of the input keys in the second area is substantially flat. The highest points of the keytops  51 ,  52  of the input keys of both the first and second groups are substantially flush with the portion  53  of the inner major surface at the second area. Accordingly, the input keys in the first area protrude from the inner major surface of the lower housing  20 , so that a user feels convexity of the individual input keys when manipulating the input keys with a finger.  
         [0040]     There will be described reasons for sectioning the inner major surface of the lower housing  20  into the first area and the second area, and lowering the inner major surface only at the first area.  
         [0041]     The input keys of the first group disposed in the first area are a so-called “tenkey”, and associated with input of telephone number, text of mail message or note, and others. In particular, when a text is inputted, a finger of the user moves in every direction across the first area. On the other hand, the input keys in the second area are associated with selection and control of various functions of the terminal, and less frequently used than the tenkey. In this way, the intended purpose or function is different between the input keys of the first group and those of the second group, and thus visually and sensuously differentiating the first group from the second group facilitates distinguishing between the two areas when the terminal is used.  
         [0042]     An antenna of this mobile phone terminal is incorporated inside the terminal, and for this and other reasons, the upper and lower housings is made of resin. Hence, when a large external force is imposed on the terminal in the folded state, the housings made of resin may deform so that a central portion of the upper housing and that of the lower housing, which are remote from the connecting portion  14  and the shock-absorbing members  24 , are made close to each other in some situations. However, even in the event of contact of the keytop of any input key with the display screen of the display  32  due to this deformation, the contact is made substantially at a point since the input key is convex outward. This makes the display screen less suffering from damage or contamination, and accordingly less susceptible to defacement. Thus, the convex shape of the keytop enhances the usability as well as prevents the defacement of the display screen.  
         [0043]     On the other hand, there is no possibility that the upper and lower housings  10 ,  20  contact each other at the second area that is relatively near the connecting portion, when the terminal receives an external force. Hence, the keytop of each input key of the second group may be substantially flat, as seen in the past. The input keys of the second group are used less frequently than the tenkey (i.e., the input keys of the first group), and thus the lack of convexity at the input keys of the second group does not much affect the usability adversely.  
         [0044]     The following effects are obtained by the present embodiment:  
         [0045]     (1) The usability of input keys of a particular group that are arranged in an area in an inner major surface of a lower housing of a terminal can be enhanced without increasing the thickness of the terminal as folded, by increasing the level difference between the keytop of each of the input keys of the group and the inner major surface, in a manner such that the inner major surface is lowered relatively to the input keys around the input keys.  
         [0046]     (2) The usability of the input keys of the particular group is enhanced since the keytop of each of the input keys of the group is convex outward to facilitate quickly sensing the individual input keys with a finger to properly position the finger as intended, during a mail message is prepared. Consequently, the usability of the terminal is enhanced, and a false operation of the terminal is prevented.  
         [0047]     (3) Damage and defacement of the display screen are prevented by the suitably determined height and shape of the keytops and other parts and elements, even where an external pressure is imposed on a terminal as folded and being carried in a pocket of clothing or a bag, e.g., where a user sits on a chair with a terminal kept in a pocket of his/her trousers.  
         [0000]     (4) An additional component is not required, and an increase in the cost due to addition of a mechanism is not involved.  
         [0048]     Although there has been described one embodiment of the invention, the invention may be embodied with various changes and modifications other than those mentioned above. For instance, the details of the mobile phone terminal shown in  FIG. 1 , such as employment, shape, and position of each of the elements shown in  FIG. 1 , is not particularly relevant to the principle of the invention, but the mobile phone terminal has been described as a specific example of a fold-type mobile terminal apparatus according to the invention. The specific figures in the above description are also presented as examples and the invention is not limited to those figures.  
         [0049]     Although in the above-described embodiment the connecting portion takes the form of a hinge arrangement, the connecting portion may be otherwise. For instance, the invention is applicable to a type of mobile terminal apparatus where an upper housing is linearly or rotationally slidable relatively to a lower housing, or another type of mobile terminal apparatus where a connecting portion connects an upper housing with the lower housing such that the upper housing can rotatable relatively to the lower housing around two axes.  
         [0050]     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.