Abstract:
It is an object of certain embodiments of the present invention to suppress variance in measurement results from a biological information measurement device and enhance measurement accuracy. A biological information measurement device comprises a main case having a sensor mounting component for mounting a sensor that senses biological information, a measurement component that connects to the sensor mounting component, a controller that connects to the measurement component, a first timer that connects to the controller, and a second timer that connects to the controller. The controller has a measurement mode in which a measurement operation is performed through the measurement component. In the measurement mode, the controller executes the measurement operation based on a preset measurement timing using the first timer, and determines the suitability of the measurement operation based on the preset measurement timing, using the second timer.

Description:
PRIORITY 
       [0001]    This is a National Stage Application under 35 U.S.C. §365 of International Application PCT/JP2013/005781, with an international filing date of Sep. 27, 2013, which claims priority to Japanese Patent Application No. 2012-224771 filed on Oct.10, 2012. The entire disclosures of International Application PCT/JP2013/005781 and Japanese Patent Application No. 2012-224771 are hereby incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates to a biological information measurement device for measuring biological information such as the glucose level in blood, for example. 
       BACKGROUND ART 
       [0003]    There are conventional biological information measurement devices that comprise, for example, a main case having a mounting component for a biological information measurement sensor, a measurement component that connects to the mounting component, a controller that connects to the measurement component, and a timer that connects to the controller. With a biological information measurement device such as this, the controller executes a measurement mode in which the measurement component measures biological information. In this measurement mode, the biological information measurement device executes a measurement operation based on a measurement timing set in advance by using the timer, and computes a blood glucose level from this measurement value (see Patent Literature 1, for example). 
       CITATION LIST 
     Patent Literature 
       [0004]    Patent Literature 1: Published Japanese Translation of PCT International Publication for Patent Application No. Heisei 5-502727 
       SUMMARY 
     Technical Problem 
       [0005]    With a conventional biological information measurement device, the measurement of biological information is executed using a timer, and a blood glucose level is calculated on the basis of the measurement value. 
         [0006]    With this type of biological information measurement device, however, there may be situations, albeit extremely rare, in which the measurement is not executed at the preset timing. The cause of this is difficult to identify, partially because it happens so rarely. However, some of the causes that are currently being considered as a possibility include the measurement environment and the power supply voltage. Although the cause has yet to be identified, there is a need for some way of dealing with the problem. That is, if the measurement is not executed at the preset timing, there will be variance in the blood glucose level that is ultimately calculated, and it may be impossible to execute the measurement accurately, and this needs to be prevented. 
         [0007]    The biological information measurement device disclosed herein provides a biological information measurement device that is effective at increasing measurement accuracy. 
       Solution to Problem 
       [0008]    The biological information measurement device pertaining to a first aspect of this disclosure comprises a main case including a sensor mounting component configured to mount a sensor that senses biological information, a measurement component that connects to the sensor mounting component, a controller that connects to the measurement component, a first timer that connects to the controller, and a second timer that connects to the controller. The controller has a measurement mode in which a measurement operation is performed through the measurement component. In the measurement mode, the controller executes the measurement operation based on a preset measurement timing using the first timer, and determines the suitability of the measurement operation based on the preset measurement timing, using the second timer. 
         [0009]    The biological information measurement device pertaining to a second aspect of this disclosure comprises a main case, a sensor mounting component, a measurement component, a controller, a first timer, and a second timer. The sensor mounting component is provided at the main case and is configured to mount a sensor that senses biological information. The measurement component connects to the sensor mounting component and measures the biological information. The controller connects to the measurement component and causes the measurement component to measure the biological information. The first timer connects to the controller and acquires at least one preset first measurement timing at which the measurement component measures the biological information. The second timer connects to the controller and acquires a second measurement timing at which the measurement component measures the biological information on the basis of the first measurement timing. The controller determines a discrepancy between the first measurement timing and the second measurement timing, and completes the measurement of the biological information by the measurement component only when the discrepancy is within a specific range. 
       Advantageous Effects 
       [0010]    The biological information measurement device disclosed herein is effective at increasing measurement accuracy. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0011]      FIG. 1  is an oblique view of the biological information measurement device pertaining to Embodiment 1; 
           [0012]      FIG. 2  is a block diagram of the biological information measurement device; 
           [0013]      FIG. 3  is a flowchart of the operation of the biological information measurement device; 
           [0014]      FIG. 4  is a graph of the waveform of applied voltage when measuring with the biological information measurement device; and 
           [0015]      FIG. 5  is a graph of the waveform of the measurement signal when measuring with the biological information measurement device. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Embodiments will now be described in detail through reference to the drawings as needed. However, some unnecessary detailed description may be omitted. For example, detailed description of already known facts or redundant description of components that are substantially the same may be omitted. This is to avoid unnecessary repetition in the following description, and facilitate an understanding on the part of a person skilled in the art. The inventors have provided the appended drawings and the following description so that a person skilled in the art might fully understand this disclosure, but do not intend for these to limit what is discussed in the patent claims. 
         [0017]      FIG. 1  is a simplified view of the exterior of a measurement device  100  (an example of a biological information measurement device) pertaining to Embodiment 1. The measurement device  100  measures the glucose level in blood (an example of biological information). The measurement device  100  comprises a main case  1  (an example of a main case). 
         [0018]    The main case  1  is formed in a substantially rectangular shape, and has at one end a sensor mounting component  3  for mounting a blood glucose level sensor  2  (an example of a sensor) in the form of a slender plate. A power switch  5  is provided at one end on the outer surface of the main case  1 , and a display component  4  (an example of a display component) is provided at the other end. 
         [0019]      FIG. 2  is a simplified diagram of the internal configuration of the measurement device  100 . As shown in  FIG. 2 , the main case  1  includes a measurement component  6  (an example of a measurement component) that is electrically connected to the sensor mounting component  3 , and a controller  7  (an example of a controller) that connects to the measurement component  6 . The controller  7  connects to the display component  4 , the power switch  5 , a battery  8 , a ROM  9  that stores a control program for the controller  7 , and a memory  10 . 
         [0020]    The controller  7  also connects to a clock  11  (an example of a first timer). The clock  11  is constituted by a quartz oscillator, for example, and therefore provides precise time and duration. The controller  7  uses the time and duration from this clock  11  to execute various control operations. 
         [0021]    The controller  7  also executes a measurement mode in which a measurement operation is performed through the measurement component  6 . In this measurement mode, a measurement operation is executed on the basis of a plurality of measurement timings that have been set in advance by using the timer function of the clock  11  (an example of a first timer). The timer, with respect to this example, uses a function where it counts upwards. A typical clock  11  using a downwards counting function may also be used. 
         [0022]    The measurement component  6  calculates a blood glucose level from a plurality of measurement values obtained on the basis of a plurality of measurement timings, and this blood glucose level is displayed on the display component  4 . 
         [0023]    Although it rarely happens, during this measurement there may be a situation in which measurement is not executed at the preset timing. The cause of this is difficult to identify, partially because it happens so rarely. However, some of the causes that are currently being considered as a possibility include the measurement environment and the power supply voltage. Although the cause has yet to be identified, there is a need for some way of dealing with the problem. That is, if the measurement is not executed at the preset timing, there may be variance in the blood glucose level that is ultimately calculated, and this needs to be suppressed. 
         [0024]    In view of this, the controller  7  in this embodiment connects to a confirmation timer  12  (an example of a second timer) that confirms the suitability of measurement based on a plurality of preset measurement timings. The controller  7  uses the confirmation timer  12  to determine whether or not there is a discrepancy between the actual measurement timing and the preset measurement timing for the measurement component  6  in the measurement mode. The confirmation timer  12  here is a count-up timer constituted by a ceramic oscillator, for example. 
         [0025]    As will be discussed in detail below, because of the above configuration, the measurement device  100  can confirm from the confirmation timer  12  whether or not the measurement executed using the clock  11  has been executed properly at the measurement timing set by the controller  7 , that is, whether or not there is a discrepancy between the preset measurement timing (an example of a first measurement timing) and the actual measurement timing (an example of a second measurement timing). This means that variance in the measurement result can be suppressed. 
         [0026]    For example, when measurement by the measurement component  6  is not executed on the basis of the measurement timing preset by the controller  7 , the user can be prompted by the display component  4  to take another measurement. In this way, the proper measurement can thereby be executed, and this improves the accuracy of the measurement result. 
         [0027]    As mentioned above, the confirmation timer  12  is a count-up timer consisting of a ceramic oscillator, and makes 1000 counts per second, for example. A ceramic oscillator is not as accurate as the quartz oscillator of the clock  11 , but the difference is only noticeable in units of months or years, and the accuracy is more than adequate for the few seconds that the measurement takes. 
         [0028]    The operation of the measurement device  100  configured as above will now be described through reference to  FIG. 3 . 
         [0029]    When a blood glucose level is measured, first the user presses the power switch  5  shown in  FIG. 1  to turn on the power, and mounts a terminal  13  provided at one end of the blood glucose level sensor  2  to the sensor mounting component  3 . This mechanically and electrically connects the terminal  13  to the sensor mounting component  3 , and completes measurement preparation (S 1  in  FIG. 3 ). 
         [0030]    The measurement component  6  applies voltage to the terminal  13  of the blood glucose level sensor  2 , detects the current flowing through the blood glucose level sensor  2 , converts the current into voltage (current-voltage conversion), and measures the voltage value. 
         [0031]    Then, when the user deposits blood on a deposition part  14  provided at the other end of the blood glucose level sensor  2 , the blood reacts with the reagent (not shown) on the blood glucose level sensor  2 . The measurement component  6  detects this reaction by voltage that has undergone current-voltage conversion, and as a result, the controller  7  detects that blood has been deposited on the deposition part  14  (S 2  in  FIG. 3 ). 
         [0032]    When the deposition of blood is detected, the controller  7  shifts into measurement mode. In the measurement mode, the controller  7  executes a blood glucose level measurement operation on the basis of a measurement timing that was set in advance by using the timer function of the clock  11 . More specifically, the controller  7  uses the timer function of the clock  11  to produce voltage switch timings t 0  to t 3  as shown in  FIG. 4 , and measurement timings tm 1  to tmn as shown in  FIG. 5 . These voltage switch timings t 0  to t 3  and measurement timings tm 1  to tmn are stored ahead of time in the memory  10 . 
         [0033]    The voltage switch timing t 0  shown in  FIG. 4  is the point when measurement is started. The controller  7  actuates the confirmation timer  12  at this voltage switch timing t 0 . The confirmation timer  12  starts counting up at 1000 counts per second, for example. The confirmation timer  12  in this embodiment is actuated by the controller  7  immediately after the controller  7  goes into the measurement mode and the measurement of the blood glucose level is started. The confirmation timer  12  may be actuated by the controller  7  before the measurement component  6  performs actual measurement to calculate the blood glucose level (S 3  in  FIG. 3 ). 
         [0034]    Also, the controller  7  uses the measurement component  6  to apply a voltage V 1  to the terminal  13  of the blood glucose level sensor  2  for a time T 1  (such as two seconds) from the voltage switch timing t 0  until the voltage switch timing t 1  in  FIG. 4  in order to promote the reaction between the deposited blood and the reagent (not shown) on the blood glucose level sensor  2  (S 3  in  FIG. 3 ). 
         [0035]    After this, the controller  7  ends the application of the voltage V 1  at the voltage switch timing t 1 , and continues the reaction between the blood and the reagent (not shown) for a specific time (such as one second) from the voltage switch timing t 1  until the voltage switch timing t 2  (S 4  in  FIG. 3 ). 
         [0036]    After this specific length of time (here, one second) has elapsed, the controller  7  uses the measurement component  6  to apply a measurement voltage V 2  to the terminal  13  of the blood glucose level sensor  2  for a measurement time T 2  (such as two seconds) from the voltage switch timing t 2  until the voltage switch timing t 3  (S 5  in  FIG. 3 ). 
         [0037]    During this measurement time T 2 , the measurement component  6  performs a plurality of actual measurements to calculate blood glucose level. 
         [0038]    Meanwhile, the count of the confirmation timer  12  is, for example, zero at the voltage switch timing t 0 , 2000 at the voltage switch timing t 1 , 3000 at the voltage switch timing t 2 , and 5000 at the voltage switch timing t 3 , according to the preset measurement timing.  FIG. 5  shows the current waveform when the above-mentioned voltage V 1  and measurement voltage V 2  are applied. 
         [0039]    The controller  7  uses the measurement component  6  to perform measurement. More specifically, during the measurement time T 2  from the voltage switch timing t 2  until the voltage switch timing t 3 , the clock  11  is used to make 20 measurements at the measurement timings tm 1 , tm 2 , tm 3 , . . . , tmn, at a measurement interval of 100 ms, for example. Meanwhile, the count of the confirmation timer  12  is 3100 at the measurement timing tm 1 , 3200 at the measurement timing tm 2 , 3300 at the measurement timing tm 3 , and 5000 at the measurement timing tmn (the voltage switch timing t 3  in this embodiment), according to the preset measurement timing. 
         [0040]    The measurement operation performed during the measurement time T 2  by the measurement device  100  pertaining to this embodiment will now be described. 
         [0041]    The controller  7  first confirms that the measurement of the clock  11  is tm 1  (S 6  in  FIG. 3 ). 
         [0042]    At this point the controller  7  acquires the count of the confirmation timer  12  (S 7  in  FIG. 3 ). 
         [0043]    It is then determined whether or not there is a discrepancy between the measurement timing preset for the measurement component  6  and the actual measurement timing (S 8  in  FIG. 3 ). More specifically, the controller  7  checks the count of the confirmation timer  12 , and if the count is within, for example, 2% (±2 counts) with respect to the measurement timing in the measurement time T 2  (a 100 ms interval), then the measured timing is deemed to be within the permissible range. That is, at the measurement timing tm 1 , when the count is within a range of 3098 to 3102, the timing of the measurement is within the permissible range, and the controller  7  determines that there is no discrepancy between the measurement timing preset for the measurement component  6  and the actual measurement timing. 
         [0044]    If there is no discrepancy in the measurement timing, the voltage detected by the measurement component  6  is measured, and this measurement value is stored in the memory  10  (S 9  in  FIG. 3 ). 
         [0045]    Thus, with the confirmation timer  12 , the controller  7  can confirm whether or not the measurement executed using the clock  11  was executed properly at the measurement timing set by the controller  7  (that is, whether or not there is any discrepancy between the predetermined measurement timing and the actual measurement timing). As a result, there is less variance in the measurement result (which can occur in rare situations), and measurement accuracy can be improved. 
         [0046]    Actual measurement is then repeated up until the measurement time T 2  has elapsed, while continuing to determine whether or not there is a discrepancy in the measurement timing. This occurs from the measurement timing tm 1  until the measurement timing tmn (S 6  to S 10  in  FIG. 3  are executed repeatedly). 
         [0047]    After this, the measurement component  6  calculates the blood glucose level on the basis of the plurality of acquired measurement values (S 11  in  FIG. 3 ). 
         [0048]    The controller  7  stops the confirmation timer  12  and ends the blood glucose level measurement. This is the end of the measurement mode, and the measurement of the blood glucose level is completed (S 12  in  FIG. 3 ). 
         [0049]    If the timing of the measurement is outside the permissible range in S 8  in  FIG. 3 , this is a state in which there is a discrepancy between the preset measurement timing and the actual measurement timing. That is, although this very rarely happens as mentioned above, it is conceivable that a situation will occur in which measurement is not executed at the preset timing. The controller  7  in this embodiment connects to the display component  4  that displays information related to whether or not there is a discrepancy between the actual measurement timing and the preset measurement timing for the measurement component  6 . 
         [0050]    Therefore, if the measurement component  6  did not execute measurement on the basis of the measurement timing preset by the controller  7 , the controller  7  instructs the display component  4  to give an error display (a display of information indicating that there is a discrepancy in the measurement timing) (S 13  in  FIG. 3 ). 
         [0051]    This error display prompts the user to take another measurement, which allows the measurement to be executed properly. As a result, the very rare occurrence of variance in the measurement result can be suppressed even further, and measurement accuracy can be improved. 
         [0052]    After this, the controller  7  returns to the process in S 2  in  FIG. 3 , and the user mounts a fresh blood glucose level sensor  2  to the sensor mounting component  3  and takes another measurement. Even if there was a discrepancy in the measurement timing during the previous measurement, it is exceedingly unlikely that this will happen consecutively. Thus, the proper measurement will more than likely be carried out this time (S 2  to S 12  in  FIG. 3 ). 
         [0053]    In this embodiment, the confirmation timer  12  is actuated when the controller  7  goes into the measurement mode in S 3  in  FIG. 3  as discussed above. That is, it is actuated before actual measurement is performed to calculate the blood glucose level by the measurement component  6  (repetition of S 6  to S 10  in  FIG. 3 ), and is halted when the measurement of the blood glucose level is completed (at the end of the measurement mode in S 11  in  FIG. 3 ). The confirmation timer  12  can be used in addition to being able to detect whether or not there is any discrepancy in the measurement timing that happens very rarely during measurement mode. When not in the measurement mode, the confirmation timer  12  can be used for other purposes which allows it to be utilized more effectively. Conversely, the timer that is used for such other purposes can be converted to use as a confirmation timer during the measurement mode. 
         [0054]    Furthermore, in this embodiment, as discussed above, the clock  11  (first timer) is constituted of a quartz oscillator, and the confirmation timer (second timer) is constituted of a ceramic oscillator. That is, the two timers are made of different materials and use separate systems. Accordingly, the independence of each timer is higher, and it can be suitably confirmed with the confirmation timer  12  (another system) whether or not measurement using the clock  11  was properly executed at the measurement timing set by the controller  7 . In this way, the measurement accuracy can be improved. 
         [0055]    In this embodiment, as discussed above, the confirmation timer  12  connects to the controller  7 , but the confirmation timer  12  may instead be provided integrally inside the controller  7 . That is, since ceramic oscillators are smaller and less expensive than quartz oscillators, they are frequently used as a signal source or reference clock for the controller  7 . When the controller  7  thus has a ceramic oscillator, if the confirmation timer  12  is provided integrally inside the controller  7 , the ceramic oscillator inside the controller  7  can be utilized, and the confirmation timer  12  can have a simpler configuration. 
         [0056]    Also, in this embodiment, the clock  11  being a quartz oscillator is used as the first timer, but a timer being a by a ceramic oscillator may instead be used as the first timer in measurement. As discussed above, a ceramic oscillator has sufficient precision within a few seconds of time (the measurement time), so the first timer can have a simpler configuration. 
         [0057]    In this embodiment, an example was described in which measurement was based on a plurality of measurement timings, but this is not the only option. The configuration may be such that if measurement based on the preset measurement timing is performed even once in the measurement mode, it is determined whether or not there is a discrepancy in the measurement timing of the measurement component  6 . 
         [0058]    Also, the blood glucose level was used as an example of biological information, but that is not the only option. For instance, it may be a cholesterol value or the like, or some other information obtained from a biological sample, such as blood or saliva. 
         [0059]    The measurement device  100  pertaining to this embodiment comprises the main case  1  including the sensor mounting component  3  (an example of a sensor mounting component) configured to mount the blood glucose level sensor  2  (an example of a sensor) that measures a blood glucose level (an example of biological information), the measurement component  6  (an example of a measurement component) that connects to the sensor mounting component  3 , the controller  7  (an example of a controller) that connects to the measurement component  6 , the clock  11  (an example of a first timer) that connects to the controller  7 , and the confirmation timer  12  (an example of a second timer) that connects to the controller  7 . The controller  7  has a measurement mode in which a measurement operation is performed through the measurement component  6 , and in this measurement mode, the controller  7  executes the measurement operation based on a preset measurement timing using the clock  11 , and determines the suitability of the measurement operation based on the preset measurement timing, using the confirmation timer  12 . 
         [0060]    With the measurement device  100  in this embodiment, the controller  7  executes a measurement operation based on the preset measurement timing using the clock  11  in the measurement mode, and the controller  7  connects to the confirmation timer  12  with which it can be confirmed as to whether or not the measurement operation has been executed properly at the measurement timing. Therefore, with the confirmation timer  12 , it can be confirmed whether or not the measurement executed using the clock  11  is executed properly at the measurement timing set by the controller  7 . As a result, the accuracy of blood glucose level measurement can be improved. 
         [0061]    For example, when measurement by the measurement component  6  is not executed on the basis of the measurement timing set by the controller  7 , the user is prompted to take another measurement, which allows the proper measurement to be executed. Thus, there is less variance in the measurement result (which can occur in rare situations). 
         [0062]    An embodiment was described above as an example of the technology disclosed herein, and the appended drawings and detailed description were provided to that end. 
         [0063]    Therefore, the constituent elements illustrated in the appended drawings and discussed in the detailed description can encompass not only those constituent elements that are essential to solving the problem, but also constituent elements that are not essential to solving the problem. Accordingly, just because these non-essential constituent elements are illustrated in the appended drawings and discussed in the detailed description, it should not be concluded that these non-essential constituent elements are essential. 
         [0064]    Also, the above embodiments were given to illustrate examples of the technology disclosed herein, so various modifications, substitutions, additions, omissions, and so forth can be made within the scope of the patent claims or equivalents thereof. 
       INDUSTRIAL APPLICABILITY 
       [0065]    This disclosure can be applied to any biological information measurement device for measuring biological information, such as the glucose level in blood.