Patent Document

RELATED APPLICATION  
       [0001]     This application is a divisional application of U.S. application Ser. No. 11/014,771, filed Dec. 20, 2004, which application claims priority under 35 U.S.C. § 119 of Japanese Application No. 2004-338323 filed Nov. 24, 2004 and Japanese Application No. 2003-423598 filed Dec. 19, 2003, and which is a continuation-in-part application of U.S. application Ser. No. 10/849,871, filed May 21, 2004, which application claims priority under 35 U.S.C. § 119 of Japanese Application No. 2003-423598 filed Dec. 19, 2003, all of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to information processing units, such as mobile phones including a PHS (Personal Handyphone System), equipped with a fingerprint sensor and operation keys.  
         [0004]     2. Description of the Related Art  
         [0005]     Recently, mobile phones have spread at a remarkable pace and have developed as portable information processing units which are equipped with multiple functions including not only simple telephone functions, but also e-mail functions and enhanced memory functions for storing various personal information such as telephone numbers.  
         [0006]     Big problems posed by such development of mobile phones include illegal use of mobile phones and unauthorized outflow of information stored in mobile phones.  
         [0007]     One of the conventional techniques used to solve these problems involves enabling the use of the mobile phone only when a registered personal identification number is entered.  
         [0008]     Since it is troublesome to enter a personal identification number, mobile phones which are equipped with a fingerprint sensor and are enabled only when a registered fingerprint is detected have recently been proposed and actually put on the market (see, for example, Japanese Patent Laid-Open No. 2002-216116 and Japanese Patent Laid-Open No. 2002-279412). The fingerprint sensor is on a considerably high level in terms of prevention of illegal use and convenience of handling.  
         [0009]     Although it is desirable from a security standpoint to mount a fingerprint sensor on mobile phones, under circumstances where there is demand for size and weight reduction of mobile phones and the mobile phones have been downsized close to the limit considering the operability for users, the question is what fingerprint sensor to mount and in what part of the mobile phones.  
         [0010]     Operation keys and a screen essential for the mobile phones are laid out in such a way as to face the user simultaneously under normal use so that the user can operate the operation key by looking at the screen. Although it is conceivable to install the fingerprint sensor in a space provided on the back face opposite the front face which contains the operation keys and screen, the fingerprint sensor functions as a kind of operation key operated by the user and installing the fingerprint sensor on the back face sacrifices the operability.  
         [0011]     Japanese Patent Laid-Open No. 2002-216116 and Japanese Patent Laid-Open No. 2002-279412 propose the use of a fingerprint sweep sensor which reads a fingerprint as the user moves a finger at right angles to a line sensor consisting of minute sensors arranged one-dimensionally.  
         [0012]     The fingerprint sweep sensor does not require much installation space and can be installed on the front face of the mobile phone without increasing the size of the mobile phone, as shown in Japanese Patent Laid-Open No. 2002-216116 and Japanese Patent Laid-Open No. 2002-279412. Japanese Patent Laid-Open No. 2002-216116 shows a drawing in which the fingerprint sweep sensor is installed adjacent to the operation keys while Japanese Patent Laid-Open No. 2002-279412 shows a drawing in which the fingerprint sweep sensor is installed adjacent to the screen.  
         [0013]     However, if the fingerprint sweep sensor is installed adjacent to the operation keys without taking any measures, there is a danger of pressing operation keys adjacent to the fingerprint sensor by mistake when moving the finger along the fingerprint sensor. Also, if the fingerprint sensor is installed adjacent to the screen, that part of the screen which is adjacent to the fingerprint sensor may become dirty by being touched by fingertips. However, installing the fingerprint sensor on that part of the mobile phone surface which is distant from the operation keys and screen to prevent the above problems would go counter to the demand for size reduction of the mobile phone.  
         [0014]     Also, the fingerprint sweep sensor, which does not require much installation space, can be installed on a flank of the mobile phone. In that case, however, the problem of operability remains, as is the case when the fingerprint sensor is installed on the back face. The above problems are not specific to mobile phones, but are common to information processing units equipped with a fingerprint sensor and operation keys.  
         [0015]     In view of the above circumstances, the present invention has an object to provide an information processing unit which is equipped with a fingerprint sensor and reconciles size reduction with operability at a high level.  
       SUMMARY OF THE INVENTION  
       [0016]     To achieve the above object, the present invention provides an information processing unit which comprises a casing equipped with a control pad, wherein:  
         [0017]     the casing comprises, adjacent to the control pad, a groove which contains a first slope stretching away from the control pad and slanting downward and a second slope stretching further away from the control pad and slanting upward;  
         [0018]     the groove comprises a fingerprint sensor which detects a fingerprint on a finger moved along the first slope and the second slope; and  
         [0019]     the first slope and the second slope have mutually different tilt angles.  
         [0020]     In the information processing unit according to the present invention, preferably the fingerprint sensor is a fingerprint sweep sensor.  
         [0021]     In the information processing unit according to the present invention, since the fingerprint sensor is contained in the groove, the first slope of the groove prevents operation keys from being pressed inadvertently when a finger is moved along the fingerprint sensor. Also, the information processing unit allows the user to move the finger along the first slope and second slope by applying it reliably to the fingerprint sensor using both sides of the slopes as a guide. This allows reliable detection of the fingerprint.  
         [0022]     Preferably, the first slope and the second slope have mutually different tilt angles which are determined from the standpoint of preventing misoperation and reliably detecting the fingerprint. In that case, preferably the first slope has a larger tilt angle than the second slope.  
         [0023]     If the fingerprint sensor installed in the information processing unit according to the present invention is a fingerprint sweep sensor, preferably the fingerprint sweep sensor has a surface protruding above an inner surface of the groove. Also, preferably the fingerprint sweep sensor is located in the groove in such a way as to hide a ridge line where an extension surface of the first slope and an extension surface of the second slope meet.  
         [0024]     By making the fingerprint sweep sensor protrude above the inner surface of the groove and lie at the bottom of the groove under which lies a ridge line, it is possible to move the finger in tight contact with the fingerprint sweep sensor, and thus detect the fingerprint reliably.  
         [0025]     As described above, by installing the fingerprint sensor adjacent to the control pad and on the same surface as the control pad, the present invention can reconcile size reduction with operability at a high level. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]      FIG. 1  is an external perspective view of a mobile phone according to an embodiment of the present invention;  
         [0027]      FIG. 2  is a plan view showing a part around a fingerprint sweep sensor of the mobile phone  100  shown in  FIG. 1 ;  
         [0028]      FIG. 3  is a sectional view taken along A-A line in  FIG. 2 ;  
         [0029]      FIG. 4  is a partially enlarged view of the part enclosed by a chain double-dashed line A in  FIG. 3 ;  
         [0030]      FIG. 5  is a diagram showing a structure of the fingerprint sweep sensor;  
         [0031]      FIG. 6  is a sectional view of a groove of a mobile phone according to a second embodiment of the present invention; and  
         [0032]      FIG. 7  is a sectional view of a groove of a mobile phone according to a third embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]     An embodiment of the present invention will be described below.  
         [0034]      FIG. 1  is an external perspective view of a mobile phone which is an embodiment of an information processing unit according to the present invention.  
         [0035]     The mobile phone  100  is a folder type phone which has a top casing  110  and bottom casing  120  pivotably joined by a hinge  130 , where the top casing  110  contains a display screen  111 , ear piece  112 , antenna  113 , etc.; and the bottom casing  120  is equipped with a operation panel  121 , mouthpiece  122 , etc. The bottom casing  120  of the mobile phone  100  contains a V-shaped groove  123  adjacent to and just below the operation panel  121 . A fingerprint sweep sensor  124  is installed at the bottom of the V-shaped groove  123 . Besides, on both sides of the V-shaped groove  123  in the bottom casing  120  are a pair of cushion pads  125  which consist of a soft material (e.g., rubber) protruding a little above the surface of the bottom casing  120  and serve as a cushion to prevent the top casing  110  from coming into direct contact with the bottom casing  120  when the top casing  110  is folded over the bottom casing  120 . According to this embodiment, the cushion pads  125  also serve as orientation marks during fingerprint detection. Details will be described later.  
         [0036]      FIG. 2  is a plan view showing a part around the fingerprint sweep sensor of the mobile phone  100  shown in  FIG. 1 ,  FIG. 3  is a sectional view taken along A-A line in  FIG. 2 , and  FIG. 4  is a partially enlarged view of the part enclosed by a chain double-dashed line A in  FIG. 3 .  
         [0037]      FIG. 2  shows three keys  121   a,    121   b,  and  121   c  located at the bottom of the multiple keys on the operation panel  121 . The V-shaped groove  123  is located just below the center key  121   b  of the three keys  121   a,    121   b,  and  121   c  at the bottom of the bottom casing  120 .  
         [0038]     The V-shaped groove  123  contains a downward slope  123   a  stretching away from the key  121   b  and an upward slope  123   b  stretching further away from the key  121   b . The V-shaped groove  123  also contains the fingerprint sweep sensor  124 .  
         [0039]     In order for the fingerprint sweep sensor  124  to detect a fingerprint, the user should apply a finger in such a way that the last joint closest to the fingertip is positioned on a straight line joining the two cushion pads  125  and move the finger along the downward slope  123   a  and upward slope  123   b  in the V-shaped groove  123  in the direction of the arrow indicated by the dotted arrow in  FIG. 2 . Consequently, the fingerprint sweep sensor  124  detects the fingerprint on the moved finger.  
         [0040]     As shown in  FIG. 3 , the downward slope  123   a  and upward slope  123   b  of the V-shaped groove  123  have different tilt angles α and β, which satisfy α&gt;β. The tilt angles α and β are determined in such a way as to prevent the key  121   b  in  FIG. 2  from being pressed by mistake during fingerprint detection and to detect the fingerprint reliably with the fingertip moved in contact with the fingerprint sweep sensor  124 .  
         [0041]     As shown in  FIG. 4 , the fingerprint sweep sensor  124  is located at the bottom of the V-shaped groove  123  under which lies a ridge line  123   c  where an extension surface of the first slope  123   a  and an extension surface of the second slope  123   b  meet. Also, the top face  124   a  of the fingerprint sweep sensor protrudes by a height b.  
         [0042]     By placing the fingerprint sweep sensor  124  at this position, it is possible to stabilize the finger pressure applied to the fingerprint sweep sensor  124  when the finger is moved along the first slope  123   a  and second slope  123   b.  This allows the fingerprint to be detected more reliably. However, the fingerprint sweep sensor  124  does not have to be placed at this position and may be placed at another place in the V-shaped groove  123  where the fingerprint can be detected reliably.  
         [0043]      FIG. 5  is a diagram showing a structure of the fingerprint sweep sensor  124 .  
         [0044]     The fingerprint sweep sensor  124  consists of a one-dimensional line sensor  126 , conductive pads  127  installed on both sides of the one-dimensional line sensor  126 , bonding wires  128  which connect the one-dimensional line sensor  126  with the conductive pads  127 , and a mold (not shown). The bonding wires  128  are installed bulging out on both sides of the one-dimensional line sensor  126 . The mold is formed in such a way as to make the V-shaped groove  123  expose only an effective area D in the center by burying the bonding wires  128 . In this way, the V-shaped groove  123  also works effectively to expose only the effective area D of the fingerprint sweep sensor  124  and hide the bulges on both sides in the bottom casing  120 .  
         [0045]     Incidentally, description has been given mainly of the placement location of the fingerprint sweep sensor and surrounding structure (including the V-shaped groove) in a mobile phone, which are typical of the above embodiment, and description of other functions of the mobile phone has been omitted. However, the mobile phone as referred to herein is irrespective of communication schemes and maybe, for example, a PHS (Personal Handyphone System).  
         [0046]     Also, it goes without saying that the information processing unit as referred to herein may be a multifunction unit equipped with not only mobile phone functions, but also, for example, e-mail functions, camera functions, etc.  
         [0047]     Furthermore, although a clamshell phone has been described herein, the present invention can be applied not only to clamshell phones, but also to various other types of phone. Furthermore, it can be applied to other information processing units such as PDAs (Personal Data Assistants).  
         [0048]     Next, other embodiments of the present invention will be described. The only difference between the following embodiments to be described and the embodiment described with reference to FIGS.  1  to  5  is in the shape of the groove where the fingerprint sweep sensor is disposed. Accordingly, the other embodiments will be described by referring to only a figure that corresponds to and is used in place of  FIG. 3  showing the shape of the groove of the above-described embodiment. The reference numerals shown in the following figures used in place of  FIG. 3  are the same as those in  FIG. 3  and only the different features will be described below.  
         [0049]      FIG. 6  is a sectional view of a groove of a mobile phone according to a second embodiment of the present invention.  
         [0050]     In the above-described embodiment, as shown in  FIG. 3 , the first slope that is the downward slope  123   a  and the second slope that is the upward slope  123   b  are both planes. However, in the second embodiment, each of the downward slope  123   a  and the upward slope  123   b  is upwardly convex as a whole and these slopes have mutually different tilt angles.  
         [0051]      FIG. 7  is a sectional view of a groove of a mobile phone according to a third embodiment of the present invention. In the third embodiment, each of the downward slope  123   a  and the upward slope  123   b  is downwardly convex (upwardly concave) as a whole and these slopes have mutually different tilt angles.  
         [0052]     As shown in these other embodiments, the downward slope  123   a  and upward slope  123   b  is not limited to a plane. The slopes may be designed to any shape as long as they are upwardly or downwardly bulging so as to prevent incorrect key operations and to detect a fingerprint without fail.

Technology Category: g