Abstract:
A biological information measurement device includes a device main body which includes a sensor, a processor, and a battery. The sensor acquires biological information of a user. The processor instructs the sensor to acquire the information at certain discrete times with a period, and processes the information. The battery supplies power to the sensor and the processor. The period is selected based on the biological information.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is based on and claims priority from Japanese Patent Application No. 2013-213480, filed Oct. 11, 2013, the disclosure of which is incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a biological information measurement device which is worn by a user so as to measure biological information, such as the user&#39;s heart rate. 
         [0004]    2. Related Art 
         [0005]    A wrist-worn heart rate monitor generally includes a device main body, which contains the necessary electronics, and a wrist band which secures the monitor to the user&#39;s wrist. It is necessary to bring the device main body into close contact with the user&#39;s skin, such as with a tightly worn elastic band which secures the monitor tightly around the wrist. Such a heart rate monitor is disclosed in JP-A-2012-90975, which is incorporated herein by reference. 
         [0006]    The heart rate monitor described in JP-A-2012-90975 is provided with first and second band members which are mounted on a device main body, and a connecting member. Each band member has a stretchable portion which expands and contracts along a longitudinal direction. The monitor also includes a power supply, such as a rechargeable battery, which drives the necessary electronic components. 
         [0007]    When the biological information is detected frequently, the battery life suffers. A large display screen further drains the battery rather quickly. A larger battery is bulky and heavy, leading to fatigue in the user. An excessively heavy batter also may adversely affect the biological information measurement at the time of motion. 
       SUMMARY 
       [0008]    A biological information measurement device includes a device main body which includes a sensor, a processor, and a battery. The sensor acquires biological information of a user. The processor instructs the sensor to acquire the information at certain discrete times with a period, and processes the information. The battery supplies power to the sensor and the processor. The period is selected based on the biological information. 
         [0009]    The processor may have several modes, each of which is associated with a different period. For example, a sleeping mode in which the user is asleep may have a first period. A light work mode in which the user is awake may have a second period shorter than the first period. An active mode in which the user is awake and in motion may have a third period shorter than the second period. 
         [0010]    The biological information may be a quantitative number, such as a pulse rate of the user. The period may be selected based on the number and/or a rate of change of the number. 
         [0011]    The battery may be a rechargeable battery, and may be charged to an amount of charge that depends on the number of discrete times at which the information was acquired after the previous charge. 
         [0012]    The period may be further selected based on the remaining amount of charge of the battery. 
         [0013]    The battery may have a charge capacity sufficient for the device to obtain the information for ten hours or more without the battery needing to be recharged. The device main body may weigh less than or equal to 60 g, have a volume less than or equal to 50 cm 3 , and/or have a thickness less than or equal to 16 mm. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
           [0015]      FIG. 1  is a top view schematically showing the external appearance of a biological information measurement device according to an embodiment. 
           [0016]      FIGS. 2A and 2B  are perspective views schematically showing the external appearance of the biological information measurement device according to the embodiment. 
           [0017]      FIG. 3  is a development view schematically showing the structure of the biological information measurement device according to the embodiment. 
           [0018]      FIG. 4  is an enlarged view schematically showing the structure of a main body section of the biological information measurement device. 
           [0019]      FIGS. 5A and 5B  are side views schematically showing the nine o&#39;clock-side side surface of the main body section of the biological information measurement device. 
           [0020]      FIGS. 6A and 6B  are a plan view and a cross-sectional view schematically showing a first band portion. 
           [0021]      FIGS. 7A to 7C  are a plan view and a cross-sectional view schematically showing a second band portion. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0022]    Hereinafter, an exemplary embodiment of the invention will be described using the drawings, which are not necessarily to scale. To the extent that relative sizes and/or shapes of components are considered relevant, these will be explicitly mentioned in the description. 
       Schematic Configuration of Biological Information Measurement Device  1   
       [0023]    A biological information measurement device  1  is an electronic device which can be worn on the wrist or other body part of a user to measure biological information of the user, such as the pulse rate. The measurement device  1  generally resembles a wristwatch, as shown in  FIGS. 1 ,  2 A, and  2 B. The measurement device  1  includes a device main body  2  which includes the electronics and measures the biological information by contacting the user&#39;s skin, and a band  3  which is mounted on the device main body  2  and serves to attach the device  1  to the user&#39;s wrist or other body part. 
       Configuration of Device Main Body  2   
       [0024]    As shown in  FIGS. 2A ,  2 B, and  3 , the device main body  2  of the measurement device  1  is provided with a module  20  ( FIG. 3 ), and a case  200  in which the module  20  is accommodated. The module  20  is provided with a display section  220 , a processing section  240 , a power supply section  260 , and a sensor section  280 . 
         [0025]    In addition, the display section  220  is provided with a first display portion  222  and a second display portion  223 . Further, the device main body  2  is provided with an operation section  250  connected to the processing section  240 , and a communication terminal  266 . In addition, the device main body  2  is provided with a battery  262  connected to the power supply section  260 , and a charging terminal  264  which is used to charge the battery  262 . 
         [0026]    In the case  200 , a concave portion  200   b  in which the module  20  is accommodated is formed on the lid section  210  side thereof. The module  20  is accommodated in the concave portion  200   b  and the lid section  210  covers the concave portion  200   b  and is fixed by setscrews  211 . Materials of the case  200  and the lid section  210  are not particularly limited. As an example thereof, nylon-based synthetic resin (plastic resin) may be used. 
         [0027]    The lid section  210  has a concave shape facing the concave portion  200   b . The depth of the concave portion  200   b  is selected according to the thickness of the battery  262  (described later). 
         [0028]    In a presently preferred embodiment, the thickness of the device main body  2  is approximately 14 mm. When the device main body  2  is thin, the user feels less pressure. Further, it is less likely to be caught in the user&#39;s clothes. The device main body  2  should be at least approximately 8 mm thick, to ensure sufficient strength, and no thicker than approximately 16 mm to avoid being caught in the user&#39;s clothes and minimize a feeling of pressure. The lid section  210  has a concave shape thick enough to accommodate the thickness of the battery  262 . 
         [0029]    The volume of the device main body  2  depends on the shape of the lid section  210 . In a presently preferred embodiment, the volume of the device main body  2  is 21 cm 3  and the device main body  2  is 14 mm thick. The device main body  2  should be at least approximately 15 cm 3 , to ensure sufficient strength, and no larger than approximately 50 cm 3  to avoid being caught in the user&#39;s clothes and minimize a feeling of pressure. 
         [0030]    As shown in  FIGS. 2A ,  2 B, and  3 , in the case  200 , a display window  200   a  is provided on the opposite side to the side on which the lid section  210  is provided. The display window  200   a  is configured such that the user&#39;s pulse rate or the like which is displayed on the display section  220  is visible through the window  200   a.    
         [0031]    The display window  200   a  is provided with a first display window  222   a  corresponding to a first display portion  222 , and a second display window  223   a  corresponding to a second display portion  223 . The first display portion  222  is fitted into the first display window  222   a  (refer to  FIGS. 1 ,  2 A,  2 B, and  4 ). Further, the second display portion  223  is fitted into the second display window  223   a  (refer to  FIGS. 1 ,  2 A,  2 B, and  4 ). 
         [0032]    As shown in  FIG. 4 , the display window  200   a  has a non-rectangular parallelogram shape with two longitudinal edges disposed along the longitudinal direction of the device, and two oblique edges  200   e ,  200   f  disposed along an oblique direction that is transverse to, but not perpendicular to, the longitudinal direction. 
         [0033]    The first display window  222   a  in which the first display portion  222  is fitted has a rectangular shape having sides  222   e  and  222   f  which extend in the lateral direction perpendicular to the longitudinal direction. 
         [0034]    The second display window  223   a  in which the second display portion  223  is fitted has several parallel sub-windows, each with a corner-rounded rectangular shape aligned in the longitudinal direction. 
         [0035]    The edge  200   e  of the display window  200   a  and the edge  222   e  of the first display window  222   a  define an acute angle therebetween. Further, the edge  200   f  of the display window  200   a  and the edge  222   f  of the first display window  222   a  define and acute angle therebetween. 
         [0036]    The second display window  223   a  is disposed in the triangular region between the edge  200   f  of the display window  200   a  and the edge  222   f  of the first display window  222   a.    
         [0037]    The second display portions  223  display an operating state or the like of the measurement device  1  in a plurality of ways. Further, it is possible to make the first display portion  222  (the first display window  222   a ) appear larger than it actually is. Therefore, it is possible to suppress a feeling of pressure which is given to a person with the measurement device  1  mounted thereon. 
         [0038]    Further, a display section cover body  202  formed of transparent resin, transparent glass, or the like is fitted into the display window  200   a . The display section  220  is protected by the display section cover body  202 . The display section cover body  202  has a non-rectangular parallelogram shape, sized to be set in the display window  200   a.    
         [0039]    As shown in  FIGS. 1 to 4 , at the case  200 , a frame section  205  is provided along the display window  200   a.    
         [0040]    In the frame section  205 , a frame portion  205 R is provided in an X1 direction (the three o&#39;clock direction when comparing the device to a wristwatch), and a frame portion  205 L is provided in an X2 direction (the nine o&#39;clock direction). 
         [0041]    Each frame portion  205 R,  205 L is shaped as an isosceles trapezoid with the bases disposed in the longitudinal direction, i.e. parallel to the edges of the band  3 . 
         [0042]    In the frame portion  205 L, one of the legs of the trapezoid disposed in a Y2 direction is provided as an extension of the oblique line of the edge  200   f  of the display window  200   a , and the other leg provided in a Y1 direction is provided further to the Y1 side (twelve o&#39;clock) than an extension of the oblique line of the edge  200   e  of the display window  200   a.    
         [0043]    In the frame portion  205 R, one of the legs of the trapezoid disposed in the Y1 direction is provided as an extension of the oblique line of the edge  200   e  of the display window  200   a , and the other leg provided in the Y2 direction is provided further to the Y2 side (six o&#39;clock) than an extension of the oblique line of the edge  200   f  of the display window  200   a.    
         [0044]    At the frame section  205 , a film  205   a  which includes metal is provided on the front side of the case  200  in which the display window  200   a  is provided. The film  205   a  is electrically connected to the processing section  240  (described later). The film  205   a  can be used as an antenna when performing wireless communication with an information processing device such as the user&#39;s computer or mobile phone (not shown) provided outside the measurement device  1 . Further, the film  205   a  can be a capacitance type touch sensor and used as the operation section  250  (described later). In addition, the film  205   a  adds to the strength of the case  200  and allows the wall thickness of the case  200  to be thinner. Therefore, it is possible to keep the weight of the case  200  down. 
         [0045]    The material of the film  205   a  is not particularly limited. In presently preferred embodiments, the material is capable of acting as an antenna and/or detecting a change in capacitance. In a particularly presently preferred embodiment, a material which includes nickel (Ni) is used. Nickel acts as an antenna, strengthens the case  200 , acts as a touch switch, and has an attractive glossy color. In addition, a presently preferred embodiment, in order to increase performance as an antenna, the strength of the case  200 , and the aesthetics, the film  205   a  is also provided on the side surface of the frame section  205 . 
         [0046]    As shown in  FIG. 3 , the display section  220  is part of the module  20  accommodated in the case  200 . The first display portion  222  and the second display portion  223  are portions of the display section  220 . 
         [0047]    In the first display portion  222 , biological information such as the number of pulses (i.e. heart beats), time information such as the current time, or the like is displayed depending on a selected display mode. Further, at the first display portion  222 , a backlight  224  is provided and can illuminate the first display portion  222 . 
         [0048]    The first display portion  222  can include any suitable hardware capable of displaying biological information (such as a numeral or a graph configured by a dot matrix) such as the pulse rate. A liquid crystal display device is one example. Further, the backlight  224  can be any suitable light of any color. One example is an electro-luminescence (EL) panel which emits green light. It is presently preferred that the first display portion  222  is a liquid crystal panel or a light-emitting diode. This leads to good battery life. 
         [0049]    The second display portion  223  can be any suitable light of any color capable of indicating the operation mode or the like of the measurement device  1  with its color, on/off state, or blinking. One example is a light-emitting diode, or, as illustrated, several light-emitting diodes. 
         [0050]    As shown in  FIG. 3 , the processing section  240  is provided in the module  20  accommodated in the case  200 . 
         [0051]    The processing section  240  includes a substrate configured as a semiconductor device such as a microcomputer or a storage device, and an electronic circuit or the like which communicates information, and the charging control of the battery  262  connected to the power supply section  260 . The display section  220 , the operation section  250 , the power supply section  260 , the sensor section  280 , and the film  205   a  of the frame section  205  are connected to the processing section  240 . The processing section  240  processes the driving of the sensor section  280  or a signal received from the sensor section  280  (e.g. the pulse rate or another signal derived from the pulse rate) so that the pulse rate or other biological information can be displayed in the display section  220 . 
         [0052]    Further, the processing section  240  stores of biological information and communicates with the information processing device provided outside the measurement device  1 , thereby outputting the stored data. 
         [0053]    As shown in  FIG. 3 , the operation section  250  providing a command to the processing section  240  is provided in the module  20  accommodated in the case  200 . 
         [0054]    The operation section  250  includes a button  252  configured to be pressed by the user, Pressing the operation button  252  may. e.g. switch between modes, such as a pulse measurement mode of displaying pulse rate; a clock mode of displaying the current time, a stopwatch time, or the like; a remaining battery level display mode; a setting mode of setting an interval of detecting the pulse or the charging capacity of the battery  262 ; a lighting mode of the backlight  224  of the display section  220 ; or the like. 
         [0055]    The operation section  250  is provided in the side surface of the case  200  in the X1 direction (the three o&#39;clock-side direction) shown in  FIGS. 1 to 4 . The operation section  250  can be provided with a plurality of operation buttons  252 . It is presently preferred that at least one operation button  252  is provided on the extension line of the edge  200   e  of the display window  200   a . In this way, the user visually recognizes the edge  200   e  of the display window  200   a , whereby it is possible to easily grasp the position where the operation button  252  is provided, and thus it is possible to prevent an erroneous operation. 
         [0056]    In a further presently preferred embodiment, pressing all the buttons  252  at substantially the same time switches to a setting mode to allow the user to set the measurement device  1 . In the illustrated embodiment, two buttons  252   a  and  252   b  are provided. The button  252   a  can be pressed by an index finger and adding a force associated with the pressing to the case  200  through a thumb. 
         [0057]    The button  252   b  can be pressed by a ring finger and adding a force associated with the pressing to the case  200  through a thumb. Therefore, it is preferable that an interval at which the operation buttons  252   a  and  252   b  are provided is an interval in which fingers (for example, a thumb and an index finger, or a thumb and a ring finger) performing the operation do not overlap, in a range that the fingers performing the operation reach. 
         [0058]    As shown in  FIG. 3 , the power supply section  260  is provided in the case section  200 . The rechargeable battery  262  is provided in the power supply section  260 . A small and lightweight battery with a high storage density is preferable. Examples are a lithium-ion polymer battery and a lithium-ion battery. 
         [0059]    The charging terminal  264  and the communication terminal  266  are provided in the side surface of the case  200  in the X2 direction (the nine o&#39;clock direction). Each of the charging terminal  264  and the communication terminal  266  is provided as a single terminal or as a plurality of terminals, depending on design considerations. In the illustrated example, two charging terminals  264  and two communication terminals  266  are provided. 
         [0060]    In the illustrated example, the communication terminals  266  are provided between the charging terminals  264 . In other words, the charging terminal  264  is disposed outside the communication terminal  266  (in the Y direction shown in  FIG. 5B ). In addition, a positioning hole  268  for a connector (not shown) to be connected to the charging terminal  264  and the communication terminal  266  is provided outside each charging terminal  264  (in the opposite Y direction). In addition, the charging terminal  264  and the communication terminal  266  protrude from the side surface of the case  200 , while the positioning hole  268  is a blind hole. 
         [0061]    As shown in  FIG. 5B , a distance d1 between each charging terminal  264  and the closest communication terminal  266  is wider than a distance d2 between the two communication terminals  266 . In this way, it is possible to avoid short circuits between the charging terminals  264  and between the charging terminal  264  and the communication terminal  266 . 
         [0062]    As for the charging terminal  264  and the communication terminal  266 , it is possible to use a material having electric conductivity, such as stainless steel, which is corrosion resistant. Further, since the charging terminal  264  and the communication terminal  266  protrude from the case  200  (such as with a convex lens-shaped convex curved surface), thus minimizing corrosion and maintaining electric conductivity. Further, the charging terminal  264  and the communication terminal  266  are provided in the side opposite the operation section  250 , and therefore, the fingers operating the operation buttons  252   a  and  252   b  do not usually touch the terminals, thereby preventing contamination due to sebum or the like. In addition, the surfaces of the charging terminal  264  and the communication terminal  266  may be plated with a conductive material having corrosion resistance, for example, gold or the like, to further improve the corrosion resistance. 
         [0063]    Returning to  FIG. 3 , the sensor section  280  will be described. 
         [0064]    As shown in  FIG. 3 , the sensor section  280  provided with a sensor unit  282  is provided in the module  20  accommodated in the case  200 . Any suitable sensor unit capable of measuring biological information, such as a pulse rate, may be used. One exemplary sensor will be described. The sensor unit  282  is a light sensor and is provided with a sensor case, and a sensor substrate with a light emitting element and a light receiving element mounted thereon. The sensor unit  282  irradiates light toward the wrist of the user from the light emitting element such as a light emitting diode (LED) and receives the light reflected by a blood vessel of the wrist by the light receiving element such as a photodiode. Such a sensor is described in detail in the present assignee&#39;s co-pending application Ser. No. 14/463,519, Attorney Docket Number 91946-082100-910013, client reference number J0173922US01, titled “Physiological Information Measuring Apparatus,” filed Aug. 19, 2014, which is hereby incorporated by reference. 
         [0065]    A sensor bank portion  212  in which the sensor section  280  is accommodated is provided at the lid section  210 . At least a portion of the sensor section  280  is provided on the sensor bank portion  212  having a disk shape recessed into the lid section  210  in the direction toward the user&#39;s skin. The sensor bank portion  212  is provided with a sensor convex portion  214  (refer to  FIG. 2B ). 
         [0066]    The sensor convex portion  214  is provided so as to be pressed against the wrist or the like of the user with the measurement device  1  mounted thereon. The sensor convex portion  214  is provided with a base portion  214   a  extending from the lid section  210 , and a tip portion  214   b  which is pressed against the user&#39;s skin. 
         [0067]    It is preferable that the base portion  214   a  of the sensor convex portion  214  is made of an opaque material and the tip portion  214   b  is made of a transparent or translucent material. Further, it is preferable that the tip portion  214   b  has a shape which avoids irregular reflection of the light and in which the user does not feel pain at the time of putting on the device. 
         [0068]    Therefore, in some embodiments, the base portion  214   a  is made of the same synthetic resin as the lid section  210  but has light-shielding coloring applied thereto. Further, the tip portion  214   b  is preferable arc shaped and made of transparent glass or transparent acrylic resin. 
       Configuration of Band  3   
       [0069]    The configuration of the band  3  will be described using  FIGS. 1 to 3 ,  6 A, and  6 B. 
         [0070]    The band  3  is provided in order to mount the device main body  2  on the user. The band  3  has two portions: one at each end of the device main body  2 , as shown in  FIGS. 1 ,  2 A, and  2 B. The first band portion  30  is mounted on a lug  203  (at the twelve o&#39;clock side) of the device main body  2  by a mounting member  32 , as shown in  FIG. 3 . Further, the second band portion  40  is mounted on a lug  204  (at the six o&#39;clock side) of the device main body  2  by a mounting member  42 . 
         [0071]    A connection portion  310  which removably connects the first band portion  30  and the second band portion  40  is provided at an end of the first band portion  30  opposite the device main body  2 . Further, a hook  410  which secures the second band portion  40  to the first band portion  30  is provided at an end of the second band portion  40  opposite the device main body  2 . 
         [0072]    In the following description, in the first band portion  30 , the device main body  2  is described as being attached to the first end, and the side on which the connection portion  310  is provided is the second end. Similarly, in the second band portion  40 , the device main body  2  side is the first end and the hook  410  is attached to the second end. 
       Configuration of First Band Portion and Second Band Portion 
       [0073]    The first band portion  30  shown in  FIGS. 3 ,  6 A, and  6 B has a belt portion  34 , a cover portion  320  as an additional connection portion provided on the first end of the belt portion  34 , and the previously mentioned connection portion  310  on the second end. The second band portion  40  shown in  FIGS. 3 , and  7 A to  7 C has the belt portion  44 , the cover portion  420  as a further connection portion provided at the first end of the belt portion  44 , and the hook  410  on the second end.  FIG. 7A  also shows a concave portion  410   c  in which the hook  410  is provided and a hole portion  440 . 
         [0074]    In the following description, the surface contacting the user&#39;s wrist is referred to as a back surface  34   b  of the belt portion  34  and a back surface  44   b  of the belt portion  44 . The opposite, visible surface is referred to as a front surface  34   a  of the belt portion  34  and a front surface  44   a  of the belt portion  44 . 
       Mounting on Device Main Body  2   
       [0075]    The first band portion  30  and second band portion  40  are mounted on the device main body  2  such that the cover portions  320 ,  420  cover the lugs  203 ,  204 , respectively, with the mounting member  32 ,  42  sandwiched between the lug  203 ,  204  and the cover portion  320 ,  420 , respectively. 
         [0076]    The cover portions  320 ,  420  and the lugs  203 ,  204  are pivotally supported by inserting respective spring rods (not shown) into respective holes  32   h ,  42   h  provided in the mounting members  32 ,  42  and rod holes  203   h ,  204   h  provided in the lugs  203 ,  204  and locking both ends of each spring rod to locking holes  320   h ,  420   h  provided in the cover portions  320 ,  420 , respectively. 
         [0077]    In the illustrated embodiment, the connection between the device main body  2  and the first band portion  30  is performed with a miter joint such that the edge  202   e  of the display section cover body  202  faces the end portions  320   e  and  32   e , which are ends of the cover portion  320  and the mounting member  32 , respectively, such that the mounting member  32  and the cover portion  320  contact the edge  200   e  of the display window  200   a . The connection between the device main body  2  and the second band portion  40  is performed with a miter joint such that the edge  202   f  of the display section cover body  202  faces the end portions  420   f  and  42   f , which are ends of the cover portion  420  and the mounting member  42 , respectively, such that the mounting member  42  and the cover portion  420  contact the edge  202   f  of the display window  200   a.    
         [0078]    Further, in the measurement device  1 , a bottomed groove (i.e. a blind groove)  290  is provided between the first band portion  30  and the device main body  2  to prevent wear due to the contact of the case  200  with the mounting member  32  and the cover portion  320  when the belt portion  34  expands or contracts. An additional bottomed groove  290  is provided between the second band portion  40  and the device main body  2  to prevent wear due to the contact of the case  200  with the mounting member  42  and the cover portion  420  when the belt portion  44  expands or contracts. 
       Belt Portions  34 ,  44   
       [0079]    The belt portions  34 ,  44  are highly elastic in order to tightly mount the device main body  2  against the wrist or the like of the user. The belt portions  34 ,  44  may be made using a material which includes polyurethane resin or silicone resin, thereby having the stretchability and flexibility of these materials. 
         [0080]    The belt portions  34 ,  44  each has a thickness in the Z direction of a central portion in a direction of a width  30 W,  40 W increased in a cross-section in the X direction, along line E-E′ in  FIG. 6A  and line F-F′ in  FIG. 7A , whereby strength during expansion and contraction and during flexion are secured. 
         [0081]    A hole  330  (in which the hook  410  of the second band portion  40  is secured) is provided in the belt portion  34 . A hole  430  (in which the projecting bar  314  of the first band portion  30  is secured) is provided in the belt portion  44 . The holes  330 ,  430  are provided in parallel in rows in the Y direction. 
         [0082]    In each hole  330 ,  430 , as shown in  FIGS. 6B and 7B , a hole portion  331 ,  431  on the front side and a hole portion  332 ,  432  on the back side are coaxial. 
         [0083]    The holes  330 ,  430  each has an elliptical shape having a major diameter in the X direction and a minor diameter in the Y direction. Both the major diameter and the minor diameter are longer in the hole portions  332 ,  432  than in the respective hole portions  331 ,  431 . 
         [0084]    In addition, the shape of the holes  431  and  432  depends on the cross-sectional shape of the projecting bar  314 . In the illustrated embodiment, the holes  431  and  432  are elliptical, thereby being able to be easily deformed, and thus the insertion of the projecting bar  314  can be easily performed. In addition, the holes  431  and  432  also have an excellent restoring force after the deformation. 
         [0085]    As shown in  FIG. 7A , numerical symbols m are provided between the rows of hole portions  430 . The values of the symbols m increase in the Y2 direction. The symbols m are, e.g. numbers 1-17, as illustrated, or a-q. The latter may sometimes be preferred because the tenth plus symbols do not take up any more room than the first through ninth, unlike with numbers. 
         [0086]    The symbols m allow the user to identify his or her unique optimum position for inserting the projecting bar  314  at a glance. Further, the symbol m is positioned between rows of hole portions  430 , and therefore, additional space is not necessary. 
         [0087]    As shown in  FIG. 7A , the belot portion  44  further includes a concave portion  400   c  in which a base portion  412  of the hook  410  is fitted. The belot portion  44  also includes the hole portion  440  in which a pin  414  extending from the base portion  412  is inserted. 
         [0088]    The concave portion  400   c  has a concave shape conforming to an outer peripheral edge of the base portion  412  on the front surface  44   a  of the belt portion. Further, a depth  400   d  of the concave portion  400   c  is approximately the same dimension as a thickness  412   t  of the base portion  412 . 
         [0089]    The hole portions  440  are provided in parallel in the X direction and coaxially with the pins  414  extending from the base portion  412 , as shown in  FIG. 7A . In the hole portion  440 , a hole (not shown) provided in a bottom portion of the concave portion  400   c  on the front surface  44   a  and a hole (not shown) in the back surface  44   b  are coaxial. 
       Connection Portion  310   
       [0090]    The connection portion  310  is provided on the second end of the belt portion  34 . 
         [0091]    A thick portion  345  whose thickness is higher than at a portion in which the holes  330  are provided is provided at the second end of the belt portion  34 . The connection portion  310  is provided at the thick portion  345 . An insertion hole  312  into which the second band portion  40  is inserted and a projecting bar  314  which is inserted into a hole portion  430  (refer to  FIGS. 7A to 7C ) provided in the second band portion  40  are provided at the connection portion  310 . 
         [0092]    The band insertion hole  312  has a width  312 W in the X direction which is wider than a width  40 W (refer to  FIG. 7A ) of the second band portion  40 . 
         [0093]    Further, the width  312 W is tapered, and is wider at the Y1 side than the Y2 side. 
         [0094]    It is therefore possible to easily insert the second band portion  40  in the Y1 side of the insertion hole  312 . Further, it is possible to tighten the band by pulling the second band portion  40  to the Y2 side. 
         [0095]    The projecting bar  314  is pivotally supported on the belt portion  34  by a spring rod (not shown) which is inserted into the locking hole  312   h  at the Y2 side of the band insertion hole  312 , and a hole (not shown) in the projecting bar  314 . A portion of the projecting bar  314  is fitted into the concave portion  312   c  at the Y1 side of the band insertion hole  312 , whereby the projecting bar  314  is locked to the belt portion  34 . 
         [0096]    Two bar portions  3141  and  3142  extend in the Y1 direction from the projecting bar  314 . A connection bar  3143  extends in the X direction. The cross-sectional shape of each of the bar portions  3141  and  3142  is flat. The projecting bar  314  has a flat shape, whereby it is possible to increase a contact area when having been inserted into the hole portion  430 , prevent the hole portion  430  from being extended, and prevent a shift of the measurement device  1  when worn by the user. Thus, the projecting bar  314  has an H-shape, and thus it is possible to easily insert the projecting bar  314  into the hole portions  430 , while maintaining an interval between the bar portions  3141  and  3142  by the connection bar  3143 . 
         [0097]    The material of the projecting bar  314  is not particularly limited, but it should have toughness capable of withstanding the restoring forces of the belt portions  34  and  44 , and corrosion resistance. Stainless steel is one example. Further, the projecting bar  314  is subjected to hairline machining along the Y direction to increase is visibility, thereby aiding insertion into the hole portion  430 . 
       Hook  410   
       [0098]    As shown in  FIGS. 1 to 3  and  FIGS. 7A to 7C , the hook  410  is provided on the second end of the belt portion  44 . 
         [0099]    As shown in  FIG. 7C , the hook  410  is provided with the base portion  412  and the pins  414  extending from the base portion  412 . The pin  414  includes a first shaft  416  and a second shaft  418 . The hook  410  locks the second band portion  40  to the first band portion  30  by inserting the pins  414  into the holes  330  of the first band portion  30 . 
         [0100]    The pins  414  are spaced apart at the same interval as the holes  330  of the belt portion  34  in the X direction, and the cross-sectional shape is elliptical to match the shape of the hole  440 , i.e. has a major diameter in the X direction and a minor diameter in the Y direction. 
         [0101]    The first shaft portion  416  protrudes from the base portion  412  at the X1 end and the second shaft portion  418  protrudes from the base portion  412  at the X2 end. 
         [0102]    A first shoulder  417  is provided on the first shaft portion  416  in the Z2 direction from the base portion  412 . The first shoulder  417  has a curved surface  417   r  at the Z2 edge. 
         [0103]    The cross-sectional area of the first shoulder  417  is larger than that of the first shaft portion  416 , larger than the hole  441 , and smaller than the hole  442 . 
         [0104]    Further, a second shoulder  419  is provided on the second shaft portion  418  in the Z2 direction from the first shaft portion  416 . The second shoulder  419  has a curved surface  419   r  at the Z2 edge. 
         [0105]    The cross-sectional area of the second shoulder  419  is larger than that of the second shaft portion  418 , larger than the hole  331 , and smaller than the hole  332 . 
         [0106]    The thickness in the Z direction of the base portion  412  and the length in the Z direction of the pin  414  are determined depending on the depths of the hole portion  440  and the hole  331  (the hole  330 ). 
         [0107]    The thickness  412   t  of the base portion  412  is approximately the same as the depth of the concave portion  400   c . A length  416 L of the first shaft portion  416  is approximately the same as the depth of the hole  441 . The thickness  417 L of the first shoulder  417  is approximately the same as the depth of the hole  442 . The length  418 L of the second shaft portion  418  is approximately the same as the depth of the hole  331 . The length  419 L of the second shoulder  419  is approximately the same as the depth of the hole  332 . 
         [0108]    The base portion  412  is fitted into the concave portion  410   c . In addition, the pins  414  are inserted into the hole portions  440 . The second shaft portions  418  protrude from the back surface  44   b  of the belt portion  44 , thereby being able to be inserted into the holes  330  in the first band portion  30 . 
         [0109]    In this way, in the first shaft portion  416  inserted into the hole  441 , the first shoulder  417  is caught in the hole  441 , and thus the hook  410  is secured to the belt portion  44 . 
         [0110]    More specifically, due to the curved surface  417   r  of the first shoulder  417 , contact resistance when inserting the first shaft portion  416  into the hole  441  is low. In addition, the curved surface  417   r  is not provided at the first shoulder  417  on the base portion  412  side, and therefore, when extracting the first shaft portion  416  from the hole  441 , a larger force than the force at the time of insertion is required. Therefore, the hook  410  is secured to the belt portion  44  until the user purposely removes it. 
         [0111]    Further, the second shoulder  419  is caught in the hole  331  in the first band portion  30 , thus securing the second band portion  40  to the first band portion  30 . 
         [0112]    More specifically, due to the curved surface  419   r  of the second shoulder  419 , contact resistance when inserting the second shaft portion  418  into the hole  331  is low. In addition, the curved surface  419   r  is not provided at the second shoulder  419  on the first shaft portion  416  side, and therefore, when extracting the second shaft portion  418  from the hole  331 , a larger force than the force at the time of insertion is required. Therefore, the second band portion  40  is secured to the first band portion  30  until the user purposely removes it. 
       Cover Portions  320 ,  420   
       [0113]    The cover portion  320  is disposed at the Y2 side of the belt portion  34 , and has the locking hole  320   h  provided therein. The cover portion  420  is disposed on the Y1 side of the belt portion  44 , and has the locking hole  420   h  provided therein. 
         [0114]    The cover portion  320  connects the first band portion  30  to the device main body  2  through the mounting member  32 . The cover portion  420  connects the second band portion  40  to the device main body  2  through the mounting member  42 . A width  320 W of the cover portion  320 , a width  420 W of the cover portion  420 , and a width  2 W of the device main body  2  are all approximately equal (in the X direction). 
         [0115]    Further, the cover portion  320  has the oblique end portion  320   e  which parallels the edge  200   e  of the non-rectangular parallelogram shaped display window  200   a  (refer to  FIG. 3 ). The cover portion  420  has the oblique end portion  420   f  which parallels the edge  200   f  of the display window  200   a . In this way, the device main body  2 , the first band portion  30 , and the second band portion  40  appear integrally formed, and thus it is possible to alleviate a feeling of pressure due to mounting. Further, since the device main body  2  does not protrude from the band portions  30 ,  40  in the width direction (the X direction), the clothes of the user are prevented from being caught on the device main body  2  at the time of putting on the apparatus. 
       Operation of Device Main Body  2   
       [0116]    The sensor section  280  of the device main body  2  can detect biological information of the user, e.g. the pulse rate. The biological information can be measured intermittently. 
         [0117]    The biological information is transmitted from the sensor unit  282  to the processing section  240  and various information processing is performed thereon. Additionally or alternatively, the biological information is displayed on the display section  220  and/or recorded in a storage device provided in the processing section  240 . The recorded biological information can be transmitted to outside of the device main body  2  by wireless communication between the device main body  2  and a receiving device (not shown) of the measurement device  1 , or by wired communication through the communication terminal  266 . 
         [0118]    Taking the pulse rate as exemplary biological information, it will be appreciated that both the pulse rate and the rate of change of the pulse rate over time are significantly different depending on the user&#39;s activity. For example, when the user is sleeping, the rate of change is small. On the other hand, when the user is in motion (walking, jogging, or the like), the rate of change is large. 
         [0119]    It is important to catch significant changes in pulse rate. Therefore, even if the pulse rate is detected continuously when the pulse rate is substantially constant, the information gleaned is not particularly useful. However, if it were detected intermittently during periods of abrupt change, it is not possible to closely monitor the change, and thus useful biological information is not obtained. 
         [0120]    Constant continuous measurements would ensure that relevant information is always captured, but the battery  262  would be quickly consumed, at which point the information could no longer be measured. 
         [0121]    Therefore, the frequency at which the pulse rate is measured can be changed depending on the detected pulse rate. In other words, when the rate of change is small, a detection interval is long, and when the rate of change is large, a detection interval is shorter. 
         [0122]    Specifically, when the pulse is less than a certain value (for example, a typical resting pulse rate, e.g. 70 bpm) and the rate of change is in a certain range, the detection period is increased. When the pulse exceeds the certain value and/or the rate of change is high, the detection period is shortened. 
         [0123]    The measurement device may be switchable between several modes, e.g. continuously measuring the biological information, displaying time of day or stopwatch time on the display section  220  without measuring the biological information, and displaying nothing without measuring the biological information. 
         [0124]    By analyzing the biological information, the device can assign an appropriate detection period needed for, for example, one day (24 hours). or to break the day up according to activity such as a daytime activity zone or a night-time sleeping zone, for example. 
         [0125]    The appropriate detection period will be different for each individual user. Therefore, it is possible for the user to set the period to any desired value by using the operating section  250 . 
         [0126]    Therefore, consumption of the battery  262  is slowed by not measuring too often when the rate of change of the information is small, thus extending the battery life. 
         [0127]    Power consumption (current consumption) in the measurement device  1  according to one exemplary embodiment will be described. 
         [0128]    When continuously measuring the pulse (at a sampling rate of 15 Hz, for example) (hereinafter referred to as a “detection mode”), current consumption is approximately 1400 μA. When displaying time or the like without measuring (including lighting of the backlight  224 , and the like, hereinafter referred to as a “time display mode”), current consumption is approximately 460 μA. When not measuring, and displaying time without the back light (“standby mode”), current consumption is approximately 350 μA. When not displaying and not measuring (“non-display mode”), current consumption is approximately 14 μA. 
         [0129]    Here, in a case where the capacity of the battery  262  (a coin type lithium-ion battery, model PD2032 is illustrated) which is installed is Typ45 (nominal 45 mA h, i.e. 45,000 μA h), in a case of continuing the detection mode (1400 μA), it is possible to continue it for approximately 32 hours. Further, in a case of continuing the time display mode (460 μA), it is possible to continue it for approximately 98 hours (four days). Further, in a case of continuing the standby mode (350 μA), it is possible to continue it for approximately 129 hours (five days). Further, in a case of continuing the non-display mode (14 μA), it is possible to continue it for approximately 3214 hours (more than four months). 
         [0130]    The detection period can be selected based on the pulse and/or the rate of change, as described above. 
         [0131]    For example, an operation of the measurement device  1  is performed at the detection mode (1400 μA) in a case where a test object is in motion. Further, the measurement device  1  operates with the ratio between the detection mode (1400 μA) and the time display mode (460 μA) being 1:1 in a case where a test object is performing light work or the like, leading to an average current of 930 μA. Further, the measurement device  1  operates with the ratio between the detection mode (1400 μA) and the standby mode (350 μA) being 1:4 when a test object is at a resting state such as sleeping, leading to an average current of 560 μA. Here, it is assumed that time when a test object is in motion is 8 hours, time when a test object is performing light work is 8 hours, and time in a resting state is 8 hours. 
         [0132]    Energy needed in order to measure biological information associated with the activity of the user is subjected to current consumption of 11,200 mA·h for 8 hours when a test object is in motion, 7,440 mA·h for 8 hours when light work is being performed, and 4,480 mA·h for 8 hours in a resting state, a total of 23,120 mA·h, leaving plenty of charge left in the 45,000 mA·h battery. Therefore, it is possible to measure the biological information continuously for 24 hours or more on a single charge. 
         [0133]    In another embodiment, an operation of the measurement device  1  is performed at the detection mode (1400 μA) in a case where a test object is in motion. Further, the measurement device  1  operates with the ratio between the detection mode (1400 μA) and the time display mode (460 μA) being 1:1 in a case where a test object is performing light work or the like, leading to an average current of 930 μA. Further, the measurement device  1  operates with the ratio between the detection mode (1400 μA) and the standby mode (350 μA) being 1:1 when a test object is at a resting state such as sleeping, leading to an average current of 875 μA. Here, it is assumed that time when a test object is in motion is 8 hours, time when a test object is performing light work is 8 hours, and time in a resting state is 8 hours. 
         [0134]    Energy needed in order to measure biological information associated with the activity of the user is subjected to current consumption of 11,200 mA·h for 8 hours when a test object is in motion, 7,440 mA·h for 8 hours when light work is being performed, and 7,000 mA·h for 8 hours in a resting state, a total of 25,640 mA·h, leaving plenty of charge left in the 45,000 mA·h battery. Therefore, it is possible to measure the biological information continuously for 24 hours or more on a single charge. 
         [0135]    It is therefore possible to obtain a full day of biological information (i.e. one daytime and one sleep cycle). A 36 hour battery life allows for obtaining, e.g., daytime→sleep→daytime. A 48 hour battery life allows for obtaining two days of data. 
         [0136]    The operation ratio can be tailored to the individual user&#39;s habits, and optimized to obtain the longest possible battery life. 
         [0137]    The battery life can also be optimized by selecting a battery  262  with an appropriate capacity, and selecting the number of batteries  262 , preferably without the thickness of the device main body  2  exceeding 16 mm. 
         [0138]    Further, it is possible to extend the detection period when the battery is running low. 
         [0139]    In other words, when the processing section  240  determines that the measurement of biological information in a measurement period set in advance cannot be achieved due to the remaining capacity of the battery  262 , the period is lengthened. In this way, even if the action of the user is different from the expected content set in advance, missing measurements are prevented. Therefore, it is possible to objectively analyze the lifestyle of the user by performing the measurement of biological information continuously over a long period of time. 
       Charging of Device Main Body  2   
       [0140]    The battery  262  should be charged when the device main body  2  is not being worn. A connector (not shown) is connected to the charging terminal  288 , and a charging control circuit, provided in the processing section  240 , controls the charging. 
         [0141]    Here, it is required that the amount of charge of the battery  262  and the capacity of the battery  262  are equal to the power (energy) amount according to the number of times of detection (a measurement period) of biological information. 
         [0142]    For example, to measure the biological information for 24 hours, the charging of power according to the detection period for 24 hours is performed. Current consumption to measure continuously for 24 hours is approximately 33,600 μA·h (approximately 1400 μA times 24 hours). Therefore, the amount of charge of the battery  262  is set to be greater than or equal to 33,600 μA·h. Measuring only during the daytime activity time zone (8 hours) requires only 11,200 μA·h (approximately 1400 μA times 8 hours). Therefore, the amount of charge of the battery  262  is set to be greater than or equal to 11,200 μA·h. The amount of charge of the battery  262  can be controlled based on biological information analyzed in the processing section  240  and is different for each user. 
         [0143]    In this way, the amount of charge can be only how much is needed, which shortens charging time and prevents deterioration of the battery  262 . 
         [0144]    The capacity of the battery  262  is selected according to measurement time and the detection period. For example, in a case of the aim being the measurement of biological information in an activity time zone, it is possible to select the battery  262  having a capacity according to a detection interval (the number of times of detection) needed in the activity time zone. For example, in a case of aiming at the measurement of biological information in a sleeping time zone, it is possible to select the battery  262  having a capacity according to a detection interval (the number of times of detection) needed in the sleeping time zone. That is, by varying the capacity of the battery  262  according to the times in which the measurement is desired, unnecessary weight is eliminated. In addition, by varying the size of the case section  200  of the device main body  2  according to the electrical capacity and the physical volume of the battery  262 , unnecessary bulk is eliminated. In other words, the device main body  2  can be available in several different sizes and each individual user can select the size that suits his or her lifestyle and personal preferences. 
         [0145]    According to the embodiment described above, the following effects can be obtained. 
         [0146]    According to the measurement device  1 , it is possible to measure the user&#39;s biological information by the sensor section  280  provided in the device main body  2  mounted on the user by the band  3 . The biological information is intermittently detected by being controlled in the processing section  240 . Therefore, power is intermittently consumed. Therefore, the amount of time until the battery becomes exhausted in increased.