Abstract:
Provided is a coordinate pointing device including a detecting unit for detecting movement of a main body of the coordinate pointing device, a signal processing unit for outputting a coordinate input signal based on information detected by the detecting unit, and a switching unit for switching a valid state in which the detecting unit detects the movement of the main body of the coordinate pointing device and an invalid state in which the detecting unit does not detect the movement of the main body.

Description:
CLAIM OF PRIORITY  
       [0001]     The present application claims priority from Japanese patent application 2005-314679 filed on Oct. 28, 2005, the content of which is hereby incorporated by reference into this application.  
       BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a coordinate pointing device for inputting coordinates.  
         [0003]     As coordinate pointing devices, there are various forms such as a mouse, a trackball, a touch panel, a touch pad, a digitizer, and a joy stick. However, nowadays, the mouse is generally used because the mouse is excellent in operability that allows a user to operate the mouse intuitively in moving the mouse, usability due to a size, weight, and the like of the mouse itself, simplicity of a structure, and durability.  
         [0004]     The user moves the mouse on a plane by gripping a housing of the mouse with a hand. When the mouse is moved, a cursor on a screen of a host apparatus to which the mouse is connected moves.  
         [0005]     As the mouse, a ball-type mouse shown in  FIG. 33  and  FIG. 35  and an optical mouse shown in  FIG. 34  and  FIG. 36  are generally known.  
         [0006]     The ball-type mouse will be explained with reference to  FIG. 33 .  
         [0007]     The ball-type mouse includes a housing  1 , a detecting unit, a signal processing unit  9 , and an interface unit.  
         [0008]     The housing  1  has a size and a shape that make it easy for the user to grip the housing  1  with a hand. The housing  1  includes at least the detecting unit and the signal processing unit  9  in an inside thereof. The housing  1  has a bottom surface of a substantially planar shape opposed to a plane  7 .  
         [0009]     The housing  1  includes sliding portions  4  in the front (hereinafter, when the user grips the mouse with a hand, a finger tip side is assumed to be the front) of the bottom surface and the rear of the bottom surface. The sliding portions  4  are made of a material having a low coefficient of friction to make it easy to slide the ball-type mouse on the plane  7 .  
         [0010]     The detecting unit includes a ball  10  and a motion sensor  11 .  
         [0011]     A part of the ball  10  projects from a ball hole near the center of the bottom surface of the housing  1 . When the user moves the ball-type mouse in a state in which the ball-type mouse is in contact with the plane  7 , the ball  10  is rotated by friction against the plane  7 .  
         [0012]     The motion sensor  11  detects the movement of the mouse from the rotation of the ball  10 . The motion sensor  11  detects the rotation of the ball  10  in two directions orthogonal to each other. Therefore, the motion sensor  11  includes rollers (not shown), which are in contact with the ball  10  and rotatable in association with the ball  10 , in the two directions orthogonal to each other. The motion sensor  11  also includes a rotary encoder that detects the rotation of the respective rollers.  
         [0013]     The rotary encoder detects the rotation of the rollers that rotate in association with the rotation of the ball  10 , with the result that the detecting unit detects the movement of the ball-type mouse.  
         [0014]     The signal processing unit  9  transmits a current position, an amount of movement, a moving direction, speed, and the like of the mouse to the interface unit as coordinate input information on the basis of information detected by the detecting unit  5 .  
         [0015]     The interface unit connects the mouse to the host apparatus. The interface unit may connect the mouse to the host apparatus by wire or by radio.  
         [0016]     A select switch  8  is used in selecting a character, a link, or the like displayed on the screen.  
         [0017]     The optical mouse will be explained with reference to  FIG. 34 .  
         [0018]     The optical mouse includes a housing  1 , a detecting unit  5 , a signal processing unit  9 , and an interface unit.  
         [0019]     The housing  1  has a size and a shape that make it easy for the user to grip the housing  1  with a hand. The housing  1  includes at least the detecting unit  5  in the inside thereof. The housing  1  has a bottom surface of a substantially planar shape opposed to a plane  7 .  
         [0020]     The housing  1  includes sliding portions  4  in the front and the rear of the bottom surface. The sliding portions  4  are made of a material with a low coefficient of friction to make it easy to slide the optical mouse on the plane  7 .  
         [0021]     The detecting unit  5  includes a light emitting unit  5   a  and a light receiving unit  5   b.    
         [0022]     The light emitting unit  5   a  includes a light emitting element such as an LED and generates light  5   c  that is made incident on the plane  7 . The light  5   c  is made obliquely incident on the plane  7  from a hole (not shown) provided in the bottom surface of the housing  1 . The light  5   c  is irregularly reflected on the plane  7  to be reflected light  5   d.    
         [0023]     The light receiving unit  5   b  includes a light receiving hole (not shown) in which the reflected light  5   d  is made incident. When the reflected light  5   d  having appropriate intensity is made incident in the light receiving hole, the light receiving unit  5   b  reads the reflected light  5   d . In other words, the light receiving unit  5   b  detects an amount of movement and a moving direction of the mouse. On the other hand, when the reflected light  5   d  having intensity lower than the appropriate intensity is made incident in the light receiving hole and when the reflected light  5   d  is not made incident in the light receiving hole, the light receiving unit  5   b  does not read the reflected light  5   d . In other words, the light receiving unit  5   b  does not detect the amount of movement and the moving direction of the mouse.  
         [0024]     The signal processing unit  9  transmits the current position, the amount of movement, the moving direction, the speed, and the like of the mouse to the interface unit as coordinate pointing information on the basis of information detected by the detecting unit  5 .  
         [0025]     The interface unit connects the mouse to the host apparatus. The interface unit may connect the mouse and the host apparatus by wire or by radio.  
         [0026]     The select switch  8  is used in selecting a character, a link, or the like displayed on the screen.  
         [0027]     The amount of movement, the moving direction, and the like of the mouse detected by the detecting unit  5  are calculated and displayed as a cursor in coordinates on the screen.  
         [0028]     When the amount of movement of the cursor calculated from a movable range of the mouse is longer than a coordinate range displayed on the screen of the host apparatus, it is possible to specify given coordinates in an entire coordinate plane of the screen within the movable range of the mouse.  
         [0029]     However, in actually using the mouse, when the user cannot secure a large movable range of the mouse, due to relative positional deviation of the cursor displayed on the screen from a position of the mouse, accuracy of coordinate resolution of the mouse, or the like, the movable range of the mouse is often narrower than the movable range of the cursor displayed on the screen of the host apparatus.  
         [0030]     Under such circumstances, when the user moves the cursor displayed on the screen of the host apparatus in excess of the movable range of the mouse, the user moves the mouse to secure a movable range of the mouse anew in a state in which the detecting unit of the mouse does not detect movement of the mouse. After that, the user brings the mouse into a state in which the detecting unit can detect movement of the mouse, moves the mouse in the movable range, and moves the cursor displayed on the screen of the host apparatus (hereinafter, referred to as “move the mouse with lifting”).  
         [0031]     When the mouse is the ball-type mouse and the optical mouse, a state in which the detecting unit of the mouse cannot detect movement of the mouse means a state in which the user lifts the mouse to allow the mouse to become apart from a contact surface as shown in  FIG. 35  and  FIG. 36 .  
         [0032]     Operation for moving the mouse with lifting makes it possible to move the mouse over an entire range on the screen of the host apparatus in a narrow movable range of the mouse. However, the user always has to lift the mouse.  
       SUMMARY OF THE INVENTION  
       [0033]     With conventional techniques as described above, it is difficult for people with a low degree of freedom of hands or fingers such as physically handicapped people and patients of tenosynovitis, in particular, people having difficulty in bending fingers or gripping an object to lift the mouse.  
         [0034]     The operation for moving the mouse with lifting has poor operability because the mouse is lifted and brought into contact with the plane. Impact caused when the mouse comes into contact with the plane imposes burdens on a wrist and fingers of the user. Moreover, sound generated when the mouse comes into contact with the plane is a nuisance for the user.  
         [0035]     It is also difficult for those who have difficulty in bending fingers to push the select switch of the usual mouse.  
         [0036]     It is therefore an object of this invention to provide a coordinate pointing device that has high operability for people having a low degree of freedom of hands and fingers and provide a mouse that does not impose burdens on a wrist and fingers.  
         [0037]     According to a representative aspect of this invention, this invention provides a coordinate pointing device including: a detecting unit for detecting movement of a main body of the coordinate pointing device; a signal processing unit for outputting a coordinate pointing signal based on information detected by the detecting unit; and switching means for switching a valid state in which the detecting unit detects the movement of the main body of the coordinate pointing device and an invalid state in which the detecting unit does not detect the movement of the main body.  
         [0038]     According to this invention, it is possible to provide a coordinate pointing device that has high operability for people having a low degree of freedom of hands and fingers. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0039]     The present invention can be appreciated by the description which follows in conjunction with the following figures, wherein:  
         [0040]      FIG. 1  is a sectional view at the time of an invalid state of a coordinate pointing device according to a first embodiment of this invention;  
         [0041]      FIG. 2  is a sectional view at the time of a valid state of the coordinate pointing device according to the first embodiment;  
         [0042]      FIG. 3  is a block diagram of the coordinate pointing device according to the first embodiment;  
         [0043]      FIG. 4  is a sectional view at the time of an invalid state of a coordinate pointing device according to a second embodiment of this invention;  
         [0044]      FIG. 5  is a sectional view at the time of a valid state of the coordinate pointing device according to the second embodiment;  
         [0045]      FIG. 6  is a sectional view at the time of an invalid state of a coordinate pointing device according to a third embodiment of this invention;  
         [0046]      FIG. 7  is a sectional view at the time of a valid state of the coordinate pointing device according to the third embodiment;  
         [0047]      FIG. 8  is a sectional view at the time of an invalid state of a coordinate pointing device according to a fourth embodiment of this invention;  
         [0048]      FIG. 9  is a sectional view at the time of a valid state of the coordinate pointing device according to the fourth embodiment;  
         [0049]      FIG. 10  is a block diagram of the coordinate pointing device according to the fourth embodiment;  
         [0050]      FIG. 11  is a sectional view at the time of an invalid state of a coordinate pointing device according to a fifth embodiment of this invention;  
         [0051]      FIG. 12  is a sectional view at the time of a valid state of the coordinate pointing device according to the fifth embodiment;  
         [0052]      FIG. 13  is a block diagram at the time of the invalid state of the coordinate pointing device according to the fifth embodiment;  
         [0053]      FIG. 14  is a block diagram at the time of the valid state of the coordinate pointing device according to the fifth embodiment;  
         [0054]      FIG. 15  is a sectional view at the time of a valid state of a coordinate pointing device according to a sixth embodiment of this invention;  
         [0055]      FIG. 16  is a block diagram of the coordinate pointing device according to the sixth embodiment;  
         [0056]      FIG. 17  is a sectional view at the time of an invalid state of a coordinate pointing device according to a seventh embodiment of this invention;  
         [0057]      FIG. 18  is a sectional view at the time of a valid state of the coordinate pointing device according to the seventh embodiment;  
         [0058]      FIG. 19  is a block diagram of the coordinate pointing device according to the seventh embodiment;  
         [0059]      FIG. 20  is a sectional view at the time of an invalid state of a coordinate pointing device according to an eighth embodiment of this invention;  
         [0060]      FIG. 21  is a sectional view at the time of a valid state of the coordinate pointing device according to the eighth embodiment;  
         [0061]      FIG. 22  is a sectional view at the time of input of a select switch of the coordinate pointing device according to the eighth embodiment;  
         [0062]      FIG. 23  is a block diagram of the coordinate pointing device according to the eighth embodiment;  
         [0063]      FIG. 24  is a sectional view at the time of an invalid state of a coordinate pointing device according to a ninth embodiment of this invention;  
         [0064]      FIG. 25  is a sectional view at the time of a valid state of the coordinate pointing device according to the ninth embodiment;  
         [0065]      FIG. 26  is a sectional view at the time of input of a select switch of the coordinate pointing device according to the ninth embodiment;  
         [0066]      FIG. 27  is a sectional view at the time of an invalid state of a coordinate pointing device according to a tenth embodiment of this invention;  
         [0067]      FIG. 28  is a sectional view at the time of a valid state of the coordinate pointing device according to the tenth embodiment;  
         [0068]      FIG. 29  is a sectional view at the time of input of a select switch of the coordinate pointing device according to the tenth embodiment;  
         [0069]      FIG. 30  is a sectional view at the time of an invalid state of a coordinate pointing device according to an eleventh embodiment of this invention;  
         [0070]      FIG. 31  is a sectional view at the time of a valid state of the coordinate pointing device according to the eleventh embodiment;  
         [0071]      FIG. 32  is a sectional view at the time of input of a select switch of the coordinate pointing device according to the eleventh embodiment;  
         [0072]      FIG. 33  is a sectional view of a conventional ball-type mouse;  
         [0073]      FIG. 34  is a sectional view of a conventional optical mouse;  
         [0074]      FIG. 35  is a diagram showing a “move the mouse with lifting” state of the conventional ball-type mouse; and  
         [0075]      FIG. 36  is a diagram showing a “move the mouse with lifting” state of the conventional optical mouse. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     First Embodiment  
       [0076]     A first embodiment of this invention will be explained with reference to  FIG. 1  to  FIG. 3 . In the first embodiment, a valid state and an invalid state of a detecting unit are switched by an elastic body in an optical mouse.  
         [0077]     The optical mouse includes a housing  1 , a detecting unit  5 , a signal processing unit  9 , and an interface unit.  
         [0078]     The housing  1  has a size and a shape that make it easy for a user to grip the housing  1  with a hand. The housing  1  includes at least the detecting unit  5  in the inside thereof. The housing  1  has a bottom surface of a substantially planar shape opposed to a plane  7 .  
         [0079]     The housing  1  includes a sliding portion  4  in the front (hereinafter, when the user grips the mouse with a hand, a finger tip side is assumed to be the front) of the bottom surface. The housing  1  includes posture changing means  2  in the rear of the bottom surface. The posture changing means  2  includes a coil spring  2   a , which is an elastic body, and a sliding portion  2   b  and changes position of housing  1  against the plane  7  when a pressure is added to the housing  1 .  
         [0080]     The coil spring  2   a  is provided between the bottom surface and the sliding portion  2   b . The sliding portion  2   b  and the sliding portion  4  are made of a material having a low coefficient of friction to make it easy to slide the mouse on the plane  7 . The coil spring  2   a  urges the rear of the mouse in a direction in which the rear of the mouse becomes apart from the plane  7  while the mouse is held in contact with the plane  7 .  
         [0081]     The detecting unit  5  includes a light emitting unit  5   a  and a light receiving unit  5   b.    
         [0082]     The light emitting unit  5   a  is constituted of an LED or the like and generates light  5   c  made incident on the plane  7 . The light  5   c  is made obliquely incident on the plane  7  from a hole (not shown) provided in the bottom surface of the housing  1 . The light  5   c  is irregularly reflected on the plane  7  to be reflected light  5   d.    
         [0083]     The light receiving unit  5   b  includes a light receiving hole (not shown) in which the reflected light  5   d  is made incident. When the reflected light  5   d  having appropriate intensity is made incident in the light receiving hole, the light receiving unit  5   b  reads the reflected light  5   d . In other words, the light receiving unit  5   b  detects an amount of movement and a moving direction of the mouse. On the other hand, when the reflected light  5   d  having intensity lower than the appropriate intensity is made incident in the light receiving hole or when the reflected light  5   d  is not made incident in the light receiving hole, the light receiving unit  5   b  does not read the reflected light  5   d . In other words, the light receiving unit  5   b  does not detect the amount of movement and the moving direction of the mouse.  
         [0084]     The detecting unit  5  detects an amount of movement and a moving direction of the mouse when a distance between the bottom surface of the housing  1  and the place  7  is h 1 .  
         [0085]     The signal processing unit  9  transmits a current position, an amount of movement, a moving direction, speed, and the like of the mouse to the interface unit as coordinate pointing information on the basis of information detected by the detecting unit  5 .  
         [0086]     The interface unit connects the mouse to the host apparatus. The interface unit may connect the mouse to the host apparatus by wire or by radio.  
         [0087]     A select switch  8  is used in selecting a character, a link, or the like displayed on the screen.  
         [0088]     As shown in  FIG. 2 , when a predetermined load is applied to the rear of the mouse by a hand  3 , the coil spring  2   a  is compressed, the bottom surface and the plane  7  are made substantially parallel, and the distance between the bottom surface and the plane  7  is set to h 1 . Therefore, the mouse is located in a position where the reflected light  5   d  having appropriate intensity is made incident in the light receiving hole. The detecting unit  5  comes into the valid state in which the detecting unit  5  is capable of detecting movement of the mouse.  
         [0089]     On the other hand, as shown in  FIG. 1 , when a load applied to the mouse is smaller than the predetermined load, the coil spring  2   a  is not completely compressed, the rear of the mouse is lifted by the coil spring  2   a , and the distance between the bottom surface and the plane  7  is set to be equal to or larger than h 1 . Therefore, the detecting unit  5  comes into a state in which the reflected light  5   d  having intensity lower than the appropriate intensity is made incident in the light receiving hole or a state in which the reflected light  5   d  is not made incident in the light receiving hole. In other words, the detecting unit  5  comes into the invalid state in which the detecting unit  5  is incapable of detecting movement of the mouse.  
         [0090]     The predetermined load with which the coil spring  2   a  is compressed and the detecting unit  5  changes from the invalid state to the valid state only has to be set to a load substantially equivalent to the own weight of the hand.  
         [0091]     When the user applies the load substantially equivalent to the own weight of the hand to the mouse in this way, since the coil spring  2   a  is compressed and the detecting unit  5   a  comes into the valid state, the detecting unit  5  detects the movement of the mouse. On the other hand, when a load applied to the mouse is smaller than the own weight of the hand, since the coil spring  2   a  is not completely compressed and the detecting unit  5   a  comes into the invalid state, the detecting unit  5  does not detect movement of the mouse.  
         [0092]     As described above, in the first embodiment, the detecting unit  5  can switch between the valid state and the invalid state according to whether the user applies the own weight of the hand to the mouse. This makes it unnecessary for the user to lift the mouse and move the mouse with lifting. Thus, it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0093]     It is preferable to use a touch sensor, an electrostatic switch, or a reflection optical switch as the select switch  8 . Since this makes it unnecessary for the user to depress the switch with a finger, burdens on the user are reduced. In addition, operability for people with a low degree of freedom of fingers is improved.  
         [0094]     It is also possible to use other elastic bodies such as a leaf spring instead of the coil spring  2   a . In this embodiment, a rear of the bottom surface of the housing  1  is urged by the coil spring  2   a  in a direction in which the rear of the bottom surface becomes apart from the plane  7 . However, the front or the sides of the bottom surface of the housing  1  may be urged by an elastic body in a direction in which the front or the sides of the bottom surface become apart from the plane  7 .  
       Second Embodiment  
       [0095]     A second embodiment of this invention will be explained with reference to  FIG. 4  and  FIG. 5 . In the second embodiment, a valid state and an invalid state of a detecting unit are switched by an elastic body in a boll-type mouse.  
         [0096]     The ball-type mouse includes a housing  1 , a detecting unit  5 , a signal processing unit  9 , and an interface unit.  
         [0097]     The housing  1  has a size and a shape that make it easy for a user to grip the housing  1  with a hand. The housing  1  includes at least the detecting unit  5  and the signal processing unit  9  in the inside thereof. The housing  1  has a bottom surface of a substantially planar shape opposed to a plane  7 .  
         [0098]     The housing  1  includes a sliding portion  4  in the rear of the bottom surface. The housing  1  includes posture changing means  2  in the front of the bottom surface. The posture changing means  2  includes a leaf spring  2   a , which is an elastic body, and a sliding portion  2   b  and changes position of housing  1  against the plane  7  when a pressure is added to the housing  1 .  
         [0099]     The coil spring  2   a  is provided between the bottom surface and the sliding portion  2   b . The sliding portion  2   b  and the sliding portion  4  are made of a material having a low coefficient of friction to make it easy to slide the mouse on the plane  7 . The coil spring  2   a  urges the front of the mouse in a direction in which the front of the mouse becomes apart from the plane  7  while the mouse is held in contact with the plane  7 .  
         [0100]     The detecting unit includes a ball  10  and a motion sensor  11 .  
         [0101]     A part of the ball  10  projects from a ball hole provided near the center of the bottom surface of the housing  1 . When the user moves the ball-type mouse in a state in which the ball-type mouse is in contact with the plane  7 , the ball  10  is rotated by friction against the plane  7 .  
         [0102]     The motion sensor  11  detects the movement of the mouse according to the rotation of the ball  10 . The motion sensor  11  detects the rotation of the ball  10  in two directions orthogonal to each other. Therefore, the motion sensor  11  includes rollers (not shown) that are in contact with the ball  10  and rotate in association with the ball  10 . The rollers are disposed in the two directions orthogonal to each other. The motion sensor  11  also includes a rotary encoder that is capable of detecting the rotation of the respective rollers.  
         [0103]     Therefore, the rotary encoder detects the rotation of the rollers, which rotate in association with the ball  10 , and the motion sensor  11  detects the movement of the ball-type mouse.  
         [0104]     The signal processing unit  9  transmits a current position, an amount of movement, a moving direction, speed, and the like of the mouse to the interface unit as coordinate pointing information on the basis of information detected by the detecting unit.  
         [0105]     The interface unit connects the mouse to the host apparatus. The interface unit may connect the mouse to the host apparatus by wire or by radio.  
         [0106]     A select switch is used in selecting a character, a link, or the like displayed on the screen.  
         [0107]     As shown in  FIG. 4 , when a predetermined load is applied to the front of the mouse by the hand  3 , the leaf spring  2   a  is compressed and the ball  10  comes into contact with the plane  7 . Therefore, since the ball rotates when the user moves the mouse, the motion sensor  11  detects the movement of the mouse. In other words, the detecting unit comes into the valid state.  
         [0108]     On the other hand, as shown in  FIG. 3 , when a load applied to the mouse is smaller than the predetermined load, the leaf spring  2   a  is not completely compressed and the front of the mouse is lifted by an urging force of the leaf spring  2   a . Therefore, since the ball  10  does not come into contact with the plane  7 , the ball does not rotate even if the user moves the mouse. The motion sensor  11  does not detect the movement of the mouse. In other words, the detecting unit comes into the invalid state.  
         [0109]     The predetermined load with which the leaf spring  2   a  is compressed and the detecting unit changes from the invalid state to the valid state only has to be set to a load substantially equivalent to the own weight of the hand.  
         [0110]     When the user applies the load substantially equivalent to the own weight of the hand to the mouse in this way, since the leaf spring  2   a  is compressed and the detecting unit comes into the valid state, the detecting unit detects the movement of the mouse. On the other hand, when a load applied to the mouse is smaller than the own weight of the hand, since the leaf spring  2   a  is not completely compressed and the detecting unit comes into the invalid state, the detecting unit does not detect the movement of the mouse.  
         [0111]     In the second embodiment, the detecting unit can switch between the valid state and the invalid state according to whether the user applies the own weight of the hand to the mouse. This makes it unnecessary for the user to lift the mouse and move the mouse with lifting. Thus, it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0112]     The select switch may be provided in a position of the housing  1  where the select switch is operable by a finger. A touch sensor, an electrostatic switch, or a reflection optical switch is used as the select switch. Since this makes it unnecessary for the user to depress the switch with a finger, burdens on the user are reduced. In addition, operability for people with a low degree of freedom of fingers is improved.  
         [0113]     It is also possible to use other elastic bodies such as a coil spring instead of the leaf spring  2   a . In this embodiment, the front of the bottom surface of the housing  1  is urged by the leaf spring  2   a  in the direction in which the front of the bottom surface becomes apart from the plane  7 . However, the rear or the sides of the bottom surface of the housing  1  may be urged by an elastic body in the direction in which the rear or the sides of the bottom surface become apart from the plane  7 .  
       Third Embodiment  
       [0114]     A third embodiment of this invention will be explained with reference to  FIG. 6  and  FIG. 7 . In the third embodiment, a valid state and an invalid state of a detecting unit are switched by an elastic body in a foot mouse.  
         [0115]     In the third embodiment, the mouse according to the second embodiment operated by the hand of the user is made operable by a foot  12  of the user. A structure according to the third embodiment is substantially identical with the structure according to the second embodiment. Components identical with those according to the second embodiment are denoted by the identical reference symbols and explanations thereof are omitted.  
         [0116]     Since the user operates the mouse with the foot  12 , the housing  1  has a size and a shape that make it easy for the user to operate the housing  1  with the foot  12 .  
         [0117]     As shown in  FIG. 7 , when a predetermined load is applied to the front of the ball-type mouse with a toe of the foot  12 , the leaf spring  2   a  is compressed and the ball  10  comes into contact with the plane  7 . Thus, when the user moves the ball-type mouse, the ball  10  rotates. Therefore, the motion sensor  11  detects the movement of the ball-type mouse. In other words, the detecting unit comes into the valid state.  
         [0118]     On the other hand, when a load applied to the front of the ball-type mouse is smaller than the predetermined load, as shown in  FIG. 6 , the leaf spring  2   a  is not completely compressed and the front of the ball-type mouse is lifted by an urging force of the leaf spring  2   a . Therefore, the ball  10  does not come into contact with the plane  7 . Since the ball does not rotate even if the user moves the ball-type mouse, the motion sensor  11  does not detect the movement of the ball-type mouse. In other words, the detecting unit comes into the invalid state.  
         [0119]     The predetermined load with which the leaf spring  2   a  is compressed and the detecting unit changes from the invalid state to the valid state only has to be set to a load substantially equivalent to the own weight of the foot  12 .  
         [0120]     When the user applies the load substantially equivalent to the own weight of the foot  12  to the ball-type mouse in this way, since the leaf spring  2   a  is compressed and the detecting unit comes into the valid state, the detecting unit detects the movement of the ball-type mouse. On the other hand, when a load applied to the ball-type mouse is smaller than the load substantially equivalent to the own weight of the foot  12 , since the leaf spring  2   a  is not completely compressed and the detecting unit comes into the invalid state, the detecting unit does not detect the movement of the ball-type mouse.  
         [0121]     In the third embodiment, it is possible to switch between the valid state and the invalid state of the detecting unit according to whether the user applies the own weight of the foot  12  to the ball-type mouse. Since the foot  12  cannot grip and lift the conventional foot mouse, the foot  12  cannot move the mouse with lifting. However, in this embodiment, it is possible to switch between the valid state and the invalid state of the detecting unit according to whether the own weight of the foot  12  is applied to the ball-type mouse. Thus, it is possible to move even a foot mouse on a screen of a host apparatus in excess of a movable range of the mouse.  
         [0122]     It is also possible to use other elastic bodies such as a coil spring instead of the leaf spring  2   a . In this embodiment, the front of the bottom surface of the housing  1  is urged by the leaf spring  2   a  in the direction in which the front of the bottom surface becomes apart from the plane  7 . However, the rear or the sides of the bottom surface of the housing  1  may be urged by an elastic body in the direction in which the rear or the sides of the bottom surface become apart from the plane  7 .  
       Fourth Embodiment  
       [0123]     A fourth embodiment of this invention will be explained with reference to  FIG. 8  to  FIG. 10 . In the fourth embodiment, a power supply to a detecting unit is switched on and off by a cut off switch in an optical mouse. Components identical with those according to the first embodiment are denoted by the identical reference symbols and explanations thereof are omitted.  
         [0124]     The housing  1  includes a cut off switch  13  in the front of the housing  1  and in a range in which the cut off switch  13  is operable by a finger. The cut off switch  13  switches a valid state and an invalid state of the detecting unit  5 . The cut off switch  13  includes a switch or a sensor that is responsive to a slight touch such as a mechanical switch that operates even with a small pressing force, a touch sensor, an electrostatic sensor, or a reflection optical sensor that has a short detection distance.  
         [0125]     As shown in  FIG. 10 , the cut off switch  13  is connected to the detecting unit  5 . When the cut off switch  13  is on, the detecting unit  5  is connected to the power supply. Therefore, power is supplied to the detecting unit  5 . The detecting unit  5  is in the valid state in which the detecting unit  5  can detect movement of the mouse. On the other hand, when the cut off switch  13  is off, the detecting unit  5  is not connected to the power supply. In other words, the supply of power to the detecting unit  5  is interrupted. Therefore, the light emitting unit  5   a  of the detecting unit  5  does not emit light. The detecting unit  5  is in the invalid state in which the detecting unit  5  cannot detect movement of the mouse.  
         [0126]     As shown in  FIG. 8 , when the user does not touch the cut off switch  13 , the cut off switch  13  is off and the supply of power to the detecting unit  5  is interrupted. Therefore, since the light emitting unit  5   a  does not emit light, even if the user moves the mouse, the detecting unit  5  cannot detect the movement of the mouse. In other words, the detecting unit  5  is in the invalid state in which the detecting unit  5  does not detect the movement of the mouse.  
         [0127]     As shown in  FIG. 9 , when the user touches the cut off switch  13 , the cut off switch  13  is on and power is supplied to the detecting unit  5 . Therefore, the light emitting unit  5   a  emits the light  5   c . The light  5   c  is irregularly reflected on the plane  7  to be the reflected light  5   d . The light receiving unit  5   b  reads the reflected light  5   d , whereby the detecting unit  5  detects the movement of the mouse. In other words, the detecting unit  5  is in the valid state in which the detecting unit  5  detects the movement of the mouse.  
         [0128]     In the fourth embodiment, it is possible to switch between the valid state and the invalid state of the detecting unit  5  using the cut off switch  13 . Since this makes it unnecessary for the user to lift the mouse and move the mouse with lifting, it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0129]     When the detecting unit  5  is in the invalid state, since the supply of power to the light emitting unit  5   a  is interrupted, it is possible to save power.  
         [0130]     The supply of power to the detecting unit  5  is interrupted without interrupting the supply of power to the mouse by the cut off switch  13 . This is because, if the supply of power to the mouse is interrupted, even connection of the power supply to the signal control unit  9  is interrupted. When the supply of power to the signal control unit  9  is stopped, the host apparatus does not recognize the mouse.  
         [0131]     The supply of power to the light receiving unit  5   b  of the detecting unit  5  may be interrupted by the cut off switch  13 .  
         [0132]     Also in the ball-type mouse, it is possible to switch between supply of power and interruption of the supply of power to the motion sensor  11  that detects the movement of the mouse by detecting the rotation of the ball  10 .  
       Fifth Embodiment  
       [0133]     A fifth embodiment of this invention will be explained with reference to  FIG. 11  to  FIG. 14 . In the fifth embodiment, in an optical mouse, signal connection between the detecting unit  5  and the signal processing unit  9  is switched by the cut off switch  13 . The fifth embodiment is identical with the fourth embodiment except a structure of the cut off switch  13 . Components identical with those according to the fourth embodiment are denoted by the identical reference symbols and explanations thereof are omitted.  
         [0134]     The housing  1  includes a cut off switch  13  in the front of the housing  1  and in a range in which the cut off switch  13  is operable by a finger. The cut off switch  13  switches a valid state and an invalid state of the detecting unit  5 . The cut off switch  13  includes a switch or a sensor that is responsive to a slight touch such as a mechanical switch that operates even with a small pressing force, a touch sensor, an electrostatic sensor, or a reflection optical sensor that has a short detection distance.  
         [0135]     As shown in  FIG. 13  and  FIG. 14 , the cut off switch  13  switches on and off of signal connection between the detecting unit  5  and the signal processing unit  9 . As shown in  FIG. 13 , when the cut off switch  13  is off, the cut off switch  13  interrupts connection between the detecting unit  5  and the signal processing unit  9 . On the other hand, as shown in  FIG. 14 , when the cut off switch  13  is on, the detecting unit  5  is connected to the signal processing unit  9  by the cut off switch  13 .  
         [0136]     As shown in  FIG. 11 , when the user does not touch the cut off switch  13 , the cut off switch  13  is off. Therefore, as shown in  FIG. 13 , the cut off switch  13  interrupts connection between the detecting unit  5  and the signal processing unit  9 . Therefore, even if the detecting unit  5  detects the movement of the mouse, since a detected signal does not reach the signal processing unit  9 , the detecting unit  5  cannot detect the movement of the mouse. In other words, the detecting unit  5  is in an invalid state. As shown in  FIG. 12 , when the user touches the cut off switch  13 , the cut off switch  13  is on. Therefore, the cut off switch  13  connects the detecting unit  5  to the signal processing unit  9 . Since a detected signal reaches the signal processing unit  9 , the detecting unit  5  detects the movement of the mouse. In other words, the detecting unit is in a valid state.  
         [0137]     In the fifth embodiment, it is possible to switch between the valid state and the invalid state of the detecting unit  5  using the cut off switch  13 . Since this makes it unnecessary for the user to lift the mouse and move the mouse with lifting, it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0138]     Even when the detecting unit  5  is in the invalid state, since the light emitting unit  5   a  emits the light  5   c , the user does not have to wait for operation for a time required until the light  5   c  stabilizes.  
         [0139]     The cut off switch  13  switches the valid state and the invalid state of the detecting unit  5  according to whether the detecting unit  5  is connected to the signal processing unit  9 . Thus, it is possible to simplify a structure of an electric circuit.  
         [0140]     In the ball-type mouse, it is also possible to detect the rotation of the ball  10  and switch a connection of a signal from the motion sensor  11 , which detects the movement of the mouse, to the signal processing unit  9  using the cut off switch  13 .  
       Sixth Embodiment  
       [0141]     A sixth embodiment of this invention will be explained with reference to  FIG. 15  and  FIG. 16 . In the sixth embodiment, the signal processing unit  9  outputs a stop signal using a cut off switch in an optical mouse. Components identical with those according to the first embodiment are denoted by the identical reference symbols and explanations thereof are omitted.  
         [0142]     The cut off switch  13  is provided separately from the mouse. The cut off switch  13  is operable by the foot  12 . The cut off switch  13  includes a pedal  13   a , a base  13   b , a contact switch  13   c , and a coil spring  13   d.    
         [0143]     The pedal  13   a  is a member on which the foot  12  is placed. The base  13   b  includes the contact switch  13   c . The coil spring  13   d  is provided between the pedal  13   a  and the base  13   b . The coil spring  13   d  urges the pedal  13   a  in a direction in which the pedal  13   a  becomes apart from the base  13   b.    
         [0144]     As shown in  FIG. 16 , the cut off switch  13  is connected to the signal processing unit  9 . As shown in  FIG. 15 , when the cut off switch  13  is off, the signal processing unit  9  outputs a stop signal to the interface unit rather than a detection signal from the detecting unit  5 . Therefore, even if the detecting unit  5  detects the movement of the mouse, a detection signal is not outputted from the signal processing unit  9 . In other words, since a detection signal from the detecting unit  5  is invalidated, the detecting unit  5  cannot detect the movement of the mouse. In other words, the detecting unit  5  is in an invalid state.  
         [0145]     When the cut off switch  13  is off, the signal processing unit  9  also invalidates an input signal from the select switch  8 . Therefore, even if the select switch  8  is operated when the cut off switch  13  is off, it is impossible to perform operation such as selection.  
         [0146]     On the other hand, when the pedal  13   a  is stepped in against an urging force of the coil spring  13   d  by the foot  12  of the user, the contact switch  13   c  comes into contact with a part of the pedal  13   a  to turn on the cut off switch  13 . When the cut off switch  13  is on, the signal processing unit  9  processes a signal detected by the detecting unit  5  as usual. Therefore, the detecting unit  5  detects the movement of the mouse. In other words, the detecting unit  5  is in a valid state.  
         [0147]     In the sixth embodiment, it is possible to switch between the valid state and the invalid state of the detecting unit  5  using the cut off switch  13 . This makes it unnecessary for the user to lift the mouse and move the mouse with lifting, so it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0148]     The cut off switch  13  is operated by the foot  12  of the user, so it is possible to reduce burdens on the wrist of the user.  
         [0149]     It is possible to apply this embodiment to a ball-type mouse by providing the cut off switch  13  operable by the foot in the ball-type mouse and adopting the same structure as the signal processing unit  9 .  
       Seventh Embodiment  
       [0150]     A seventh embodiment of this invention will be explained with reference to  FIG. 17  to  FIG. 19 . In the seventh embodiment, when the mouse is located in a position where the reflected light  5   d  having appropriate intensity is made incident in the light receiving hole, power is supplied to the detecting unit  5  by the cut off switch  13  to bring the detecting unit  5  into a valid state. Components identical with those according to the first embodiment are denoted by the identical reference symbols and explanations thereof are omitted.  
         [0151]     The housing  1  includes the posture changing means  2  in the rear of the bottom surface. The posture changing means  2  includes the coil spring  2   a , which is an elastic body, and the sliding portion  2   b.    
         [0152]     The coil spring  2   a  is provided between the bottom surface and the sliding portion  2   b . The sliding portion  4  is made of a material having a low coefficient of friction to make it easy to slide the mouse on the plane  7 . The housing  1  also includes the sliding portion  4  made of a material having a low coefficient of friction in the front of the bottom surface. The coil spring  2   a  urges the mouse in a direction in which the mouse becomes apart from the plane  7  while being held in contact with the plane  7 .  
         [0153]     The housing  1  includes the cut off switch  13  in the rear thereof. The cut off switch  13  includes a push button switch.  
         [0154]     As shown in  FIG. 18 , when a predetermined load is applied to the rear of the mouse by the hand  3 , the coil spring  2   a  is compressed, the bottom surface and the plane  7  are made substantially parallel, the distance between the bottom surface and the plane  7  is set to h 1 , and the mouse is located in a position where the reflected light  5   d  having appropriate intensity can be made incident in the light receiving hole. When the coil spring  2   a  is compressed, the push button switch is pressed by the sliding portion  2   b  to turn on the cut off switch  13 . As the cut off switch  13  is turned on, the detecting unit  5  is connected to the power supply and power is supplied to the detecting unit  5 . Therefore, the reflected light  5   d  having appropriate intensity is made incident in the light receiving hole and the detecting unit  5  comes into the valid state in which the detecting unit  5  is capable of detecting the movement of the mouse.  
         [0155]     On the other hand, as shown in  FIG. 17 , when a load applied to the coil spring  2   a  is smaller than the predetermined load, the coil spring  2   a  is not completely compressed and the rear of the mouse is lifted by the coil spring  2   a . In this state, the cut off switch  13  is off, the power supply is not connected to the detecting unit  5 , and the supply of power to the detecting unit  5  is interrupted. Therefore, since the light emitting unit  5   a  does not emit light, even if the user moves the mouse, the detecting unit  5  cannot detect the movement of the mouse. In other words, the detecting unit  5  is in an invalid state.  
         [0156]     The predetermined load with which the coil spring  2   a  is compressed and the detecting unit  5  changes from the invalid state to the valid state only has to be set to a load substantially equivalent to the own weight of the hand.  
         [0157]     In the seventh embodiment, it is possible to switch between the valid state and the invalid state of the detecting unit  5  according to on and off of the cut off switch  13 , that is, whether the own weight of the hand of the user is applied to the mouse. This makes it unnecessary for the user to lift the mouse and move the mouse with lifting, so it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0158]     When the detecting unit  5  is in the invalid state, power is not supplied to the detecting unit  5 , so it is possible to save power.  
         [0159]     Only when the mouse is located in a position where the light  5   c  is reflected on the plane and made incident on the light receiving unit, the cut off switch  13  is on. Thus, the mouse moves following operation of the select switch  8 . It is possible to surely prevent a misoperation for selecting a wrong place.  
         [0160]     The supply of power to the light receiving unit  5   b  of the detecting unit  5  may be interrupted by the cut off switch  13 .  
         [0161]     It is also possible to apply this embodiment to a ball-type mouse by supplying power to the motion sensor  11 , which detects the rotation of the ball  10  and detects the movement of the mouse, using the cut off switch  13  when the mouse is located in a position where the reflected light  5   d  having appropriate intensity is made incident in the light receiving hole.  
         [0162]     It is possible to use other elastic bodies such as a leaf spring instead of the coil spring  2   a . In this embodiment, the rear of the bottom surface of the housing  1  is urged in the direction in which the rear of the bottom surface becomes apart from the plane  7  by the coil spring  2   a . However, the front or the sides of the bottom surface of the housing  1  may be urged in the direction in which the front or the sides of the bottom surface become apart from the plane  7 .  
       Eighth Embodiment  
       [0163]     An eighth embodiment of this invention will be explained with reference to  FIG. 20  to  FIG. 23 . In the eighth embodiment, in an optical mouse, when a first predetermined load substantially equivalent to the own weight of the hand is applied to the mouse by an elastic body, the mouse is located in a position where the reflected light  5   d  having appropriate intensity is made incident in the light receiving hole and power is supplied to the detecting unit  5  by the cut off switch  13  to bring the detecting unit  5  into a valid state. Moreover, when a second predetermined load larger than the first predetermined load is applied to the mouse, the elastic body is further compressed and the select switch is operated. Components identical with those according to the first embodiment are denoted by the identical reference symbols and explanations thereof are omitted.  
         [0164]     The housing  1  has, in the front thereof, a cutoff unit obtained by cutting off a part of the housing  1 . The cutoff unit includes a two-stage switch  15 . A sliding portion  17  and the sliding portion  4  are made of a material having a low coefficient of friction. The sliding portion  17  is provided on a surface on the plane  7  side of the two-stage switch  15  via a coil spring  16 . The coil spring  16  urges the mouse in the direction in which the mouse becomes apart from the plane  7  while being held in contact with the plane  7 .  
         [0165]     The two-stage switch  15  serves as both the cut off switch  13  and the select switch  8 . The cut off switch  13  switches the detecting unit  5  to a valid state and an invalid state. The select switch  8  is used in selecting a character, a link, or the like displayed on the screen.  
         [0166]     To be specific, the two-stage switch  15  has two contacts that are switched by a load applied to the two-stage switch  15 . A first contact is the cut off switch  13 . The first contact is turned on when a predetermined first predetermined load is applied thereto. As shown in  FIG. 23 , the first contact is connected to the detecting unit  5 . When the first contact is on, the power supply is connected to the detecting unit  5  and power is supplied to the detecting unit  5 . When the first contact is off, the detecting unit  5  is not connected to the power supply and the supply of power to the detecting unit  5  is interrupted.  
         [0167]     A second contact is the select switch  8 . The second contact is turned on when a predetermined second predetermined load larger than the first predetermined load, with which the first contact operates, is applied to the second contact. As shown in  FIG. 23 , the second contact is connected to the signal processing unit  9 . When the second contact is on, the signal processing unit  9  detects operation of the select switch  8 . When the second contact is off, the signal processing unit  9  does not detect operation of the select switch  8 .  
         [0168]     As shown in  FIG. 20 , when a load applied to the mouse is smaller than the first predetermined load, the coil spring  16  is not completely compressed and the front of the mouse is lifted by the coil spring  16 . In this state, the cut off switch  13  of the two-stage switch  15  is off and the supply of power to the detecting unit  5  is interrupted. Therefore, the light emitting unit  5   a  does not emit light, so even if the user moves the mouse, the detecting unit  5  cannot detect the movement of the mouse. In other words, the detecting unit  5  is in the invalid state. The select switch  8  of the two-stage switch  15  is off and operation of the select switch  8  is not detected.  
         [0169]     As shown in  FIG. 21 , when a load applied to the mouse is larger than the first predetermined load and smaller than the second predetermined load, the coil spring  16  is compressed, the bottom surface of the housing  1  is made substantially parallel to the plane  7 , the distance between the bottom surface and the plane  7  is set to h 1 , and the mouse is located in a position where the reflected light  5   d  having appropriate intensity is made incident in the light receiving hole. The cut off switch  13  of the two-stage switch  15  is turned on. The detecting unit  5  is connected to the power supply and power is supplied to the detecting unit  5 . Therefore, the reflected light  5   d  having appropriate intensity is made incident in the light receiving hole and the detecting unit  5  comes into the valid state in which the detecting unit  5  detects the movement of the mouse. The select switch  8  of the two-stage switch  15  is off and operation of the select switch  8  is not detected.  
         [0170]     As shown in  FIG. 22 , when a load applied to the mouse is larger than the second predetermined load, the coil spring  16  is further compressed and the mouse inclines forward. In other words, the bottom surface of the housing  1  inclines to the front of the mouse with respect to the plane  7 . In this state, the cut off switch  13  of the two-stage switch  15  is off and the supply of power to the detecting unit  5  is interrupted. Therefore, the light emitting unit  5   a  does not emit light, so even if the user moves the mouse, the detecting unit  5  cannot detect the movement of the mouse. In other words, the detecting unit  5  is in the invalid state. The second contact is on, so the signal processing unit  9  recognizes that the select switch  8  is operated.  
         [0171]     The first predetermined load with which the cut off switch  13  of the two-stage switch  15  is turned on only has to be set to a load substantially equivalent to the own weight of the hand. The second predetermined load with which the select switch  8  of the two-stage switch  15  is turned on only has to be set to a predetermined load larger than the own weight of the hand.  
         [0172]     In the eighth embodiment, it is possible to switch between the valid state and the invalid state of the detecting unit  5  according to on and off of the cut off switch  13  of the two-stage switch  15 , that is, whether the own weight of the hand of the user is applied to the mouse. This makes it unnecessary for the user to lift the mouse and move the mouse with lifting, so it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0173]     When the detecting unit  5  is in the invalid state, power is not supplied to the detecting unit  5 , so it is possible to save power.  
         [0174]     The supply of power to the light receiving unit  5   b  of the detecting unit  5  may be interrupted by the cut off switch  13 .  
         [0175]     Moreover, when the switch of the second contact of the two-stage switch  15  is turned on and off, or the predetermined load larger than the own weight of the hand of the user is applied to the mouse, the select switch is inputted. Thus, it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0176]     When the select switch is inputted, or the second contact is on, the detecting unit  5  is in the invalid state, so even if the mouse moves following operation of the select switch  8 , it is possible to prevent a misoperation for selecting a wrong place.  
       Ninth Embodiment  
       [0177]     A ninth embodiment of this invention will be explained with reference to  FIG. 24  to  FIG. 26 . In the ninth embodiment, in a ball-type mouse, a valid state and an invalid state of a detecting unit are switched by an elastic body to make it possible to input the select switch  8  according to a load applied to the mouse. Components identical with those according to the second embodiment are denoted by the identical reference symbols and explanations thereof are omitted.  
         [0178]     The housing  1  includes a select switch  18   c  in the front of the bottom surface thereof. The housing  1  includes a sliding portion  18   a  in the front of the bottom surface thereof via a leaf spring  18   b . The leaf spring  18   b  urges the mouse in the direction in which the mouse becomes apart from the plane  7  while being held in contact with the plane  7 .  
         [0179]     The select switch  18   c  includes a push button switch. The select switch  18   c  is used in selecting a character, a link, or the like displayed on the screen. The leaf spring  18   b  is compressed to a degree at which the ball  10  is brought into contact with the plane  7  by a load substantially equivalent to the own weight of the hand  3 . When a predetermined load larger than the own weight of the hand is applied to the select switch  18   c , the leaf spring  18   b  is compressed and the sliding portion  18   a  presses the push button of the select switch  18   c  to turn on the select switch  18   c . The select switch  18   c  is connected to the signal processing unit  9 .  
         [0180]     As shown in  FIG. 24 , when a load applied to the mouse is smaller than the own weight of the hand  3 , the leaf spring  18   b  is not compressed and the ball  10  does not come into contact with the plane  7 . Thus, the detecting unit does not detect the movement of the mouse. In other words, the detecting unit is in the invalid state. The push button of the select switch  18   c  and the sliding portion  18   a  are spaced apart from each other, so the select switch  18   c  is off and operation of the select switch  18   c  is not detected.  
         [0181]     As shown in  FIG. 25 , when a load substantially equivalent to the own weight of the hand  3  is applied to the mouse, the leaf spring  18   b  is compressed and the ball  10  comes into contact with the plane  7 . Therefore, the movement of the mouse allows the ball  10  to rotate and the detecting unit can detect the movement of the mouse. In other words, the detecting unit is in the valid state. Since the push button of the select switch  18   c  and the sliding portion  18   a  are apart from each other, the select switch  18   c  is off and operation of the select switch  18   c  is not detected.  
         [0182]     As shown in  FIG. 26 , when the predetermined load larger than the own weight of the hand  3  is applied to the mouse, the leaf spring  2   a  is further compressed. The bottom surface of the housing  1 , that is, the mouse inclines to the front side and the ball  10  comes into contact with the plane  7 . Therefore, the movement of the mouse allows the ball  10  to rotate and the detecting unit can detect the movement of the mouse. In other words, the detecting unit is in the valid state. Since the push button of the select switch  18   c  is pressed by the sliding portion  18   a , the select switch  18   c  is on and operation of the select switch  18   c  is detected.  
         [0183]     In the ninth embodiment, it is possible to switch between the valid state and the invalid state of the detecting unit according to whether the own weight of the hand of the user is applied to the mouse. This makes it unnecessary for the user to lift the mouse and move the mouse with lifting, so it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0184]     When the predetermined load larger than the own weight of the hand of the user is applied to the mouse, the select switch  18   c  is inputted. Thus, it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
       Tenth Embodiment  
       [0185]     A tenth embodiment of this invention will be explained with reference to  FIG. 27  to  FIG. 29 . In the tenth embodiment, in a ball-type mouse, a detecting unit is brought into a valid state by a load applied to the mouse to make it possible to input the select switch  19 . Components identical with those according to the second embodiment are denoted by the identical reference symbols and explanations thereof are omitted.  
         [0186]     The housing  1  includes leaf springs  20   b  in the front and the rear of the bottom surface thereof. The housing  1  includes sliding portions  20   a  in the front and the rear of the bottom surface via the leaf springs  20   b . The leaf springs  20   b  urge the mouse in the direction in which the mouse becomes apart from the plane  7  while being held in contact with the plane  7 .  
         [0187]     The housing  1  includes a ball storing unit capable of storing a ball in a state in which a part of the ball  10  is allowed to project from the bottom surface of the housing  1 . The ball storing unit includes the select switch  19 . The select switch  19  includes a push button switch. The select switch  19  is used in selecting a character, a link, or the like displayed on the screen. As the push button of the select switch  19  is pressed by the ball  10 , the select switch  19  is turned on. A contact unit of the select switch  19 , which comes into contact with the ball  10 , is made of a material having a low coefficient of friction. The select switch  19  is connected to the signal processing unit  9 .  
         [0188]     As shown in  FIG. 27 , when a load applied to the mouse is smaller than the own weight of the hand  3 , the leaf spring  20   b  is not compressed and the ball  10  does not come into contact with the plane  7 . Thus, the detecting unit does not detect the movement of the mouse. In other words, the detecting unit is in the invalid state. Since the push button of the select switch  19  and the ball  10  are spaced apart from each other, the select switch  19  is off and operation of the select switch  19  is not detected.  
         [0189]     As shown in  FIG. 28 , when a load substantially equivalent to the own weight of the hand  3  is applied to the mouse, the leaf spring  20   b  is compressed and the ball  10  comes into contact with the plane  7 . Therefore, the movement of the mouse allows the ball  10  to rotate and the detecting unit can detect the movement of the mouse. In other words, the detecting unit is in the valid state. The push button of the select switch  19  and the ball  10  are apart from each other, so the select switch  19  is off and operation of the select switch  19  is not detected.  
         [0190]     As shown in  FIG. 29 , when the predetermined load larger than the own weight of the hand  3  is applied to the mouse, the leaf spring  20   b  is further compressed. The ball  10  then comes into contact with the plane  7 . Therefore, the movement of the mouse allows the ball  10  to rotate and the detecting unit can detect the movement of the mouse. In other words, the detecting unit is in the valid state. The select switch  19  is pressed by the ball  10 , so the select switch  19  is on and operation of the select switch  18   c  is detected.  
         [0191]     Moreover, even when the select switch  19  is on, or the ball  10  is in contact with the select switch  19 , the contact unit of the select switch  19  with the ball  10  is made of the material having a low coefficient of friction, so the ball  10  is capable of rotating because of the friction against the plane  7 . Therefore, even at the time of operation of the select switch  19 , the detecting unit is in the valid state, so it is possible to perform operation of so-called click-and-drag.  
         [0192]     In the tenth embodiment, it is possible to switch between the valid state and the invalid state of the detecting unit according to whether the own weight of the hand of the user is applied to the mouse. This makes it unnecessary for the user to lift the mouse and move the mouse with lifting. Thus, it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0193]     When the predetermined load larger than the own weight of the hand of the user is applied to the mouse, the select switch  19  is inputted. Thus, it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
       Eleventh Embodiment  
       [0194]     An eleventh embodiment of this invention will be explained with reference to  FIG. 30  to  FIG. 32 . In the eleventh embodiment, in an optical mouse, a detecting unit is brought into a valid state by a load applied to the mouse to make it possible to operate the select switch  19 . Components identical with those according to the first embodiment are denoted by the identical reference symbols and explanations thereof are omitted.  
         [0195]     The housing  1  includes the cut off switch  13  in the front of the bottom surface thereof. The cut off switch  13  switches a valid state and an invalid state of the detecting unit  5 . The housing  1  includes the sliding portion  4  and a coil spring  4   a  in the front of the bottom surface. The sliding portion  4  is provided in the cut off switch  13  via the coil spring  4   a . The coil spring  4   a  urges the mouse in the direction in which the mouse becomes apart from the plane  7  while being held in contact with the plane  7 .  
         [0196]     The cut off switch  13  includes a push button switch. When a predetermined first predetermined load is applied to the cut off switch  13 , the coil spring  4   a  is compressed and the sliding portion  4  presses the push button of the cut off switch  13  to turn on the cut off switch  13 . When the cut off switch  13  is on, the detecting unit  5  is connected to the power supply. When the cut off switch  13  is off, the detecting unit  5  is not connected to the power supply.  
         [0197]     On the other hand, the housing  1  includes a select switch  21  in the front of a top surface on the opposite side of the bottom surface. The select switch  21  is used in selecting a character, a link, or the like displayed on the screen. The housing  1  includes a hand rest  22 , on which the hand  3  of the user is placed, at the rear end of the top surface. The hand rest  22  is provided on the top surface of the housing  1  so as to be rotatable. A coil spring  22   a  is provided between the hand rest  22  and the select switch  21 . The coil spring  22   a  urges the hand rest  22  in a direction in which the hand rest  22  becomes apart from the top surface of the housing  1 .  
         [0198]     The select switch  21  includes a push button switch. When a second predetermined load larger than the first predetermined load is applied to the select switch  21 , the coil spring  22   a  is compressed and the hand rest  22  presses the push button of the select switch  21  to turn on the select switch  21 . When the select switch  21  is on, an input signal of the select switch  21  is transmitted to the signal processing unit  9 . When the select switch  21  is off, an input signal of the select switch  21  is not transmitted to the signal processing unit  9 .  
         [0199]     As shown in  FIG. 30 , when a load applied to the mouse is smaller than the first predetermined load, the coil spring  4   a  is not compressed and the front of the mouse is lifted by the coil spring  4   a . The coil spring  22   a  is not compressed and the front of the hand rest  22  is lifted by the coil spring  22   a . Therefore, the cut off switch  13  and the select switch  21  are off. Since the cut off switch  13  is off, the power supply is not connected to the detecting unit  5  and power is not supplied to the detecting unit  5 . In other words, the detecting unit  5  is in the invalid state. Since the select switch  21  is also off, a signal from the select switch  21  is not transmitted to the signal processing unit  9 .  
         [0200]     As shown in  FIG. 31 , when a load applied to the mouse is larger than the first predetermined load and smaller than the second predetermined load, the coil spring  4   a  is compressed, the bottom surface of the housing is made substantially parallel to the plane  7 , and the distance between the bottom surface of the housing  1  and the plane  7  is set to h 1 . Since the coil spring  4   a  is compressed to press the push button of the cut off switch  13 , the cut off switch  13  is on. Therefore, the power supply is connected to the detecting unit  5  and power is supplied to the detecting unit  5 . Therefore, the detecting unit  5  is in the valid state in which the detecting unit  5  detects the movement of the mouse.  
         [0201]     The coil spring  22   a  is not compressed and the front of the hand rest  22  is lifted by the coil spring  22   a . Therefore, since the select switch  21  is off, a signal from the select switch  21  is not transmitted to the signal processing unit  9 .  
         [0202]     As shown in  FIG. 32 , when the second predetermined load larger than the first predetermined load is applied to the mouse, the coil spring  4   a  is kept compressed and the distance between the bottom surface of the housing  1  and the plane  7  continues to be h 1 . Since the coil spring  4   a  is kept compressed and presses the push button of the cut off switch  13 , the cut off switch  13  is on. Therefore, the power supply is connected to the detecting unit  5  and power is supplied to the detecting unit  5 . Therefore, the detecting unit  5  is in the valid state in which the detecting unit  5  detects the movement of the mouse.  
         [0203]     The coil spring  22   a  is compressed and the push button of the select switch  21  is pressed by the hand rest  22 . Therefore, the select switch  21  is turned on and a signal is transmitted from the select switch  21  to the signal processing unit  9 .  
         [0204]     The first predetermined load only has to be set to a load substantially equivalent to the own weight of the hand. Therefore, the second predetermined load is a predetermined load larger than the own weight of the hand.  
         [0205]     In the eleventh embodiment, it is possible to switch between the valid state and the invalid state of the detecting unit  5  according to whether the own weight of the hand is applied to the mouse. This makes it unnecessary for the user to lift the mouse and move the mouse with lifting. Thus, it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0206]     When the second predetermined load larger than the own weight of the hand is applied to the mouse, the select switch  21  is inputted, so it is possible to provide a mouse that has high operability for people with a low degree of freedom of hands and fingers. It is also possible to provide a mouse that does not impose burdens on a wrist and fingers.  
         [0207]     A spring constant of the coil spring  4   a  is set smaller than a spring constant of the coil spring  22   a , so it is possible to turn on the select switch  21 , or input the select switch  21 , while keeping the detecting unit  5  in the valid state. Thus, it is possible to perform operation of so-called click-and-drag.  
         [0208]     While the present invention has been described in detail and pictorially in the accompanying drawings, the present invention is not limited to such detail but covers various obvious modifications and equivalent arrangements, which fall within the purview of the appended claims.