Patent Publication Number: US-2017367649-A1

Title: Biological information measuring device

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This is a Continuation Application of PCT Application No. PCT/JP16/055588, filed on Feb. 25, 2016, which was published under PCT Article 21(2) in Japanese. The present application is based on Japanese Patent Application No. 2015-038728 filed on Feb. 27, 2015, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to living body information measuring instrument. 
     BACKGROUND ART 
     Living body information measuring instruments are known which can measure living body information such as a pulse rate and a blood pressure continuously (for each beat) using information that is detected by a pressure sensor in a state that the pressure sensor is in direct contact with a living body part where an artery such as a wrist radius artery runs (refer to JP-2004-113368-A, JP-H02-261421-A, JP-H07-124130-A, JP-H01-242031-A and JP-2010-220949-A). 
     In the blood pressure measuring instrument disclosed in JP-2004-113368-A, blood pressure values in a part that is different from a living body part to which a pressure sensor is brought into contact are calculated using a cuff and calibration data is generated using the calculated blood pressure values. Blood pressure values are calculated for each beat by calibrating a pressure pulse wave detected by the pressure sensor using the calibration data. 
     JP-H02-261421-A, JP-H07-124130-A and JP-H01-242031-A disclose blood pressure measuring instruments which measure a blood pressure for each beat without using a cuff, that is, using only information detected by a pressure sensor that is set in contact with a wrist. 
     The living body information measuring instrument disclosed in JP-2010-220949-A is of a wrist watch type and is configured such that a display unit is located on the palm side in a state that it is attached to a wrist. Living body information (exercise strength, pulse rate, etc.) that has been measured on the basis of pressure pulse waves detected by the pressure sensor are displayed on the display unit. 
     WO-2012-018029-A discloses a blood pressure measuring instrument that is not of such a type that a pressure sensor is brought into contact with a living body part but a wrist watch type blood pressure measuring instrument capable of measuring a blood pressure by exerting pressure on a wrist using a cuff. This blood pressure measuring instrument is configured such that in a state that it is attached to a wrist a display unit is located on the back side of the hand and measured blood pressure values etc. are displayed on it. 
     In living body information measuring instruments that are used being attached to a wrist as disclosed in JP-2010-220949-A and WO-2012-018029-A, inconvenience may occur if a display unit is located only the back side or the palm side of the hand. 
     For example, assume a case that a living body information measuring instrument is used in a hospital or the like and a health care professional is going to check living body information displayed on a display unit of the living body information measuring instrument that is attached to a wrist of a patient. The patient may not be able to move his or her hand in a desired manner depending on his or her physical condition, disease-related condition, or the like. In such a situation, it is necessary for the health care professional to check a display on the display unit by moving the wrist of the patient, which may be burdensome to both of the health care professional and the patient. Furthermore, where the patient is in a situation that he or she cannot move his or her hand in a desired manner, it is difficult to the patient to check information on the display unit. 
     For certain humans, it is more difficult to do an action for checking information on a display unit that is located on the palm side of a hand than on a display unit that is located on the back side of a hand. On the other hand, if a display unit is provided only on the back side of a hand, the display unit located there is easy to see to others, resulting is difficulty preserving his or her privacy. 
     SUMMARY 
     One object of the invention is therefore to provide a living body information measuring instrument which allows both of a measurement-subject person and a third person to check measured living body information easily by giving a higher degree of freedom to the manner of display of measured living body information and enables consideration for preservation of the privacy of the measurement-subject person. 
     A living body information measuring unit according to the invention is a wrist-mounted living body information measuring instrument having a living body information measuring unit for measuring living body information on the basis of a living body signal detected from a wrist, including a main body which forms a space into which the wrist can be inserted; a first display unit and a second display unit which are provided on an outer circumference of the main body; and a display control unit which performs display controls on the first display unit and the second display unit, wherein the first display unit and the second display unit are disposed such that the space exists on a straight line that connects a center of a display screen of the first display unit and a center of a display screen of the second display unit, and a center of the space is located between the center of the display screen of the first display unit and the center of the display screen of the second display unit in a direction that is perpendicular to a palm in a state that the living body information measuring instrument is attached to the wrist. 
     The invention can provide a living body information measuring instrument which allows both of a measurement-subject person and a third person to check measured living body information easily by giving a higher degree of freedom to the manner of display of measured living body information and enables consideration for preservation of the privacy of the measurement-subject person. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an appearance view showing the configuration of a blood pressure measuring instrument  200  for description of an embodiment of the present invention. 
         FIG. 2  is a view, as viewed from the palm side, of the blood pressure measuring instrument  200  of  FIG. 1  being attached to a wrist. 
         FIG. 3  is a view, as viewed from the hand back side, of the blood pressure measuring instrument  200  of  FIG. 1  being attached to the wrist. 
         FIG. 4  is an appearance view showing the configuration of a pressure pulse wave detection unit  100  of the blood pressure measuring instrument  200  shown in  FIG. 1 . 
         FIG. 5  is an enlarged view of the pressure pulse wave detection unit  100  shown in  FIG. 4 . 
         FIG. 6  is a view, as viewed from the side of the fingertips of the user, of the pressure pulse wave detection unit  100  shown in  FIG. 4  that is in an attached state. 
         FIG. 7  is a view, as viewed from the side of the part being in contact with the wrist, of the pressure pulse wave detection unit  100  shown in  FIG. 4  that is in an attached state. 
         FIG. 8  shows a block configuration of the blood pressure measuring instrument other than the pressure pulse wave detection unit  100 . 
         FIG. 9  is a flowchart illustrating an operation, to generation of calibration data in a continuous blood pressure measurement mode, of the pressure measuring instrument according to the embodiment. 
         FIGS. 10A and 10B  are diagrams for showing an example state that a radius artery is not closed by one of two sensor portions. 
         FIGS. 11A and 11B  are diagrams for showing examples of amplitude values of pressure pulse waves that are detected by pressure sensors of a sensor unit  6  as the pressing force that the sensor unit  6  exerts on the wrist is varied. 
         FIGS. 12A to 12C  are diagrams for showing how pressing of the sensor unit  6  against the wrist by an air bag  2  proceeds after attachment of the pressure pulse wave detection unit  100  to the wrist. 
         FIG. 13  is a graph showing an example of how a pressure pulse wave detected by an optimum pressure sensor varies as the pressure acting on the wrist is varied. 
         FIG. 14  shows example pulse wave envelope data. 
         FIG. 15  is a flowchart illustrating a continuous blood pressure measuring operation in the continuous blood pressure measurement mode of the blood pressure measuring instrument according to the embodiment. 
         FIG. 16  shows example displays to be made on the screens of display units  104  and  105  of the blood pressure measuring instrument  200  shown in  FIG. 1 . 
         FIG. 17  shows other example displays to be made on the screens of display units  104  and  105  of the blood pressure measuring instrument  200  shown in  FIG. 1 . 
         FIG. 18  shows a modification (modified in terms of appearance) of the blood pressure measuring instrument  200  shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment of the present invention will be hereinafter described with reference to the drawings. 
       FIG. 1  is a side view showing the configuration of a blood pressure measuring instrument  200  which is an example living body information measuring instrument for description of the embodiment of the invention. The blood pressure measuring instrument  200  shown in  FIG. 1  is a wrist-mounted living body information measuring instrument to be used being attached to a wrist of a measurement-subject person where a radius artery (blood pressure measurement target) exists. 
     A body (main body) of the blood pressure measuring instrument  200  is equipped with a body unit  101 , a body unit  102 , and a hinge  103  which connects the body units  101  and  102 . The body unit  102  is connected to the body unit  101  by the hinge  103  so as to be swingable with respect to the latter. 
     The inner circumferential surfaces of the body units  101  and  102  are shaped so as to conform to the outer shape of a wrist H. A space Ka into which the wrist H of the measurement-subject person can be inserted is formed between the body units  101  and  102  in a state that an end portion, opposite to the hinge  103 , of the body unit  101  is set closest to the body unit  102 . 
     The body units  101  and  102  are fixed to each other by a belt  106  in a state that the wrist H is inserted in the space Ka, whereby the blood pressure measuring instrument  200  is fixed (attached) to the wrist H. 
     The body unit  101  is equipped with a pressure pulse wave detection unit  100  which is disposed at such a position as to be opposed to the wrist H in a state that the blood pressure measuring instrument  200  is attached to the wrist H and a display unit  104  which functions as a first display unit mounted in the outer circumferential surface. 
     The body unit  102  is equipped with a display unit  105  which functions as a second display unit mounted in its outer circumferential surface. 
     The display units  104  and  105  are disposed such that the space Ka which is formed by the body which is composed of the body units  101  and  102  and the hinge  103  exists on a straight line L that connects the center of the display screen of the display unit  104  and the center of the display screen of the display unit  105 . The center of the display screen of the display unit  104  and the center of the display screen of the display unit  105  are different from each other in their positions in a direction D that is perpendicular to the palm of the hand of the measurement-subject person in a state that the blood pressure measuring instrument  200  is attached to the wrist H of the measurement-subject person. 
     In the example of  FIG. 1 , in the direction D, the display unit  104  is disposed on the palm side of the center of the space Ka and the display unit  105  is disposed on the hand back side of the center of the space Ka. 
       FIG. 2  is a view, as viewed from the palm side, of the blood pressure measuring instrument  200  being attached to the left wrist of the measurement-subject person. As shown in  FIG. 2 , the outer circumferential surface of the body unit  101  is formed with the display unit  104 , which is therefore be viewable from the palm side. 
       FIG. 3  is a view, as viewed from the hand back side, of the blood pressure measuring instrument  200  being attached to the left wrist of the measurement-subject person. As shown in  FIG. 3 , the outer circumferential surface of the body unit  102  is formed with the display unit  105 , which is therefore viewable from the hand back side. 
       FIG. 4  is an appearance view showing the configuration of the pressure pulse wave detection unit  100  of the blood pressure measuring instrument  200  of  FIGS. 2 and 3  being attached to the wrist. Only the pressure pulse wave detection unit  100  of the blood pressure measuring instrument  200  is shown in  FIG. 4 . 
       FIG. 5  is an enlarged view of the pressure pulse wave detection unit  100  shown in  FIG. 4 .  FIG. 6  is a view, as viewed from the side of the fingertips of the measurement-subject person, of the pressure pulse wave detection unit  100  shown in  FIG. 4  that is in an attached state.  FIG. 7  is a view, as viewed from the side of the part being in contact with the wrist, of the pressure pulse wave detection unit  100  shown in  FIG. 4  that is in an attached state.  FIGS. 4 to 7  are schematic views of pressure pulse wave detection unit  100  and should not be construed as restricting the dimensions of individual portions, their arrangement, and other things. 
     The pressure pulse wave detection unit  100  is equipped with a body  1  which incorporates an air bag  2 , a flat plate member  3  which is fixed to the air bag  2 , a rotary member  5  which is supported by a biaxial rotating mechanism  5   a  so as to be rotatable about each of two axes relative to the flat plate member  3 , and a sensor unit  6  which is attached to a flat surface, opposite to the flat plate member  3 , of the rotary member  5 . 
     The air bag  2  functions as a pressing unit for pressing a pressing surface  6   b  of the sensor unit  6  against an artery that is located under the skin of a living body part (wrist) in a state that the blood pressure measurement device  200  is attached to the wrist. The pressing unit may be any kind of unit as long as it can press the pressing surface  6   b  of the sensor unit  6  toward an artery; it is not limited to units that employ an air bag. 
     The amount of air existing inside the air bag  2  is controlled by a pump (not shown), whereby the air bag  2  moves the flat plate member  3  which is fixed to the air bag  2  in the direction that is perpendicular to a surface (a flat surface located on the rotary member  5  side) of the flat plate member  3 . 
     In the attached state shown in  FIG. 4 , the pressing surface  6   b  of the sensor unit  6  which is included in the pressure pulse wave detection unit  100  is in contact with the skin of the wrist of the measurement-subject person. When the amount of air injected in the air bag  2  is increased in this state, the internal pressure of the air bag  2  is increased, whereby the sensor unit  6  is pushed toward a radius artery T that exists in the wrist. The following description will be made with an assumption that the pressure force that is exerted toward the radius artery T by the sensor unit  6  is equivalent to the internal pressure of the air bag  2 . 
     As shown in  FIG. 7 , the pressing surface  6   b  is formed with plural pressure sensors  6   a  (pressure detecting elements) which are arranged in a direction B that crosses (in the example of  FIG. 4 , is perpendicular to) a direction A in which the radius artery T extends that exists in the attachment target part, in the attached state shown in  FIG. 4 . The pressing surface  6   b  is also formed with plural pressure sensors  7   a  which are arranged in the direction B. Each pressure sensor  6   a  and a pressure sensor  7   a  that is located at the same position as the pressure sensor  6   a  in the direction B constitute a pair, and plural such pairs are arranged in the direction B on the pressing surface  6   b . The pressure sensors (plural pressure sensors  6   a  and plural pressure sensors  7   a ) included in the pressure pulse wave detection unit  100  constitute a pressure detection unit. 
     The pressing surface  6   b  is a surface of a semiconductor substrate which is made of, for example, single crystal silicon and the pressure sensors  6   a  and  7   a  are, for example, pressure-sensitive diodes formed on the surface of the semiconductor substrate. 
     The pressure sensors  6   a  ( 7   a ) are pressed against the radius artery T such that its arrangement direction crosses (is approximately perpendicular to) the radius artery T, and the pressure sensors  6   a  detect a pressure vibration wave (i.e., pressure pulse wave) that is generated from the radius artery T and transmitted to the skin. The pressure pulse wave is included in living body information. 
     The interval between the pressure sensors  6   a  ( 7   a ) is set sufficiently small so that a necessary and sufficient number of pressure sensors  6   a  ( 7   a ) are arranged over the radius artery T. The arrangement length of the pressure sensors  6   a  ( 7   a ) is set necessarily and sufficiently greater than the diameter of the radius artery T. 
     As shown in  FIG. 7 , the biaxial rotating mechanism  5   a  is a mechanism for rotating the rotary member  5  about each of two rotation axes X and Y which are perpendicular to the direction in which the flat plate member  3  is pushed by the air bag  2 . 
     The biaxial rotating mechanism  5   a  has the two orthogonal rotation axes X and Y which are set on the surface of the flat plate member  3  and about each of which rotational driving is performed by a rotational drive unit  10  (described later). 
     The rotation axis Y is a first axis that extends in the arrangement direction of the plural pressure sensors  6   a  ( 7   a ) formed on the pressing surface  6   b . As shown in  FIG. 7  (plan view), the rotation axis Y is set between (in the example of  FIG. 7 , at the center of) the element array of the plural pressure sensors  6   a  and the element array of the plural pressure sensors  7   a.    
     The rotation axis X is a second axis that extends in the direction that is perpendicular to the arrangement direction of the plural pressure sensors  6   a  ( 7   a ) formed on the pressing surface  6   b . In the example of  FIG. 7 , the rotation axis X is set as a straight line that equally divides each of the element array of the plural pressure sensors  6   a  and the element array of the plural pressure sensors  7   a.    
     When the rotary member  5  is rotated about the rotation axis X, the pressing surface  6   b  is rotated about the rotation axis X. When the rotary member  5  is rotated about the rotation axis Y, the pressing surface  6   b  is rotated about the rotation axis Y. 
       FIG. 8  shows a block configuration of the blood pressure measuring instrument  200 . 
     The blood pressure measuring instrument  200  is equipped with the pressure pulse wave detection unit  100 , a rotational drive unit  10 , an air bag drive unit  11 , a control unit  12  for centralized control of the entire instrument, the display units  104  and  105 , a manipulation unit  14 , and a memory  15 . 
     The rotational drive unit  10  is an actuator that is connected to each of the rotation axes (shafts) X and Y of the biaxial rotating mechanism  5   a  of the pressure pulse wave detection unit  100 . The rotational drive unit  10  rotates the pressing surface  6   b  about the rotation axes X and Y by rotationally driving the rotation axes (shafts) X and Y individually according to an instruction from the control unit  12 . 
     The air bag drive unit  11  controls the amount of air to be injected in the air bag  2  (an internal pressure of the air bag  2 ) according to an instruction from the control unit  12 . 
     Each of the display units  104  and  105  serves to display various kinds of information such as measured blood pressure values and employs, for example, a liquid crystal display device, an organic electro luminescence display device, or an electronic paper display. 
     The manipulation unit  14 , which is an interface for input of an instruction signal for the control unit  12 , is composed of buttons for commanding a start of any of various operations including a blood pressure measurement and other components. 
     The memory  15  includes a ROM (read-only memory) for storing programs and data for allowing the control unit  12  to perform prescribed operations, a RAM (random access memory) as a working memory, a flash memory for storing various kinds of information such as measured blood pressure data, and other components. 
     The control unit  12  functions as a pressing control unit, a living body information measuring unit, a rotation control unit, a calibration data generation unit, and a display control unit by running the programs stored in the ROM of the memory  15 . 
     The pressing control unit controls the pressing force that the pressing surface  6   b  exerts on the wrist by adjusting the amount of air that occupies the inside the air bag  2  by controlling the air bag drive unit  11 . 
     The living body information measuring unit calculates first blood pressure values in the radius artery T on the basis of pressure pulse waves that are detected by the pressure sensors  6   a  and  7   a  formed in the pressing surface  6   b  in a state that the pressing surface  6   b  is pressed toward the radius artery T. 
     More specifically, the living body information measuring unit calculates first blood pressure values in the radius artery T on the basis of pressure pulse waves that were detected by the pressure sensors  6   a  and  7   a  in a process that the pressing force acting on the radius artery T was varied (increased or decreased) by the air bag drive unit  11 . 
     The calibration data generation unit generates calibration data using the first blood pressure values calculated by the first blood pressure calculation unit. 
     The rotation control unit judges whether it is necessary for the rotational drive unit  10  to rotate the pressing surface  6   b , on the basis of pressure pulse waves that were detected by the pressure sensors  6   a  and  7   a  in a process that the pressing force acting on the radius artery T was increased by the air bag drive unit  11 . If judging that rotation is necessary, the rotation control unit causes the rotational drive unit  10  to rotate the pressing surface  6   b.    
     The living body information measuring unit calculates second blood pressure values in the radius artery T for each beat by calibrating, using the calibration data, a pressure pulse wave that is detected by the pressure sensors  6   a  and  7   a  for each beat in a state that the pressing surface  6   b  is pressed toward the radius artery T with an optimum pressing force for deforming part of the radius artery T into a flat shape. Furthermore, the living body information measuring unit calculates a pulse rate on the basis of pressure pulse waves detected for respective beats. 
     The display control unit performs a display control on each of the display units  104  and  105 . 
     A description will be made below of how the blood pressure measuring instrument according to the embodiment operates. The blood pressure measuring instrument according to the embodiment has a continuous blood pressure measurement mode in which a blood pressure value SBP (systolic blood pressure; what is called a maximum blood pressure) and a blood pressure value DBP (diastolic blood pressure; what is called a minimum blood pressure) are measured and displayed on the display unit  104  beat by beat. 
       FIG. 9  is a flowchart for illustrating an operation, to generation of calibration data in the continuous blood pressure measurement mode, of the pressure measurement device  200 . 
     It is assumed that in an initial state, that is, a state before reception of a blood pressure measurement instruction, the rotation amount of the rotary member  5  of the pressure pulse wave detection unit  100  is set at, for example, zero, that is, the pressing surface  6   b  is parallel with the flat plate member  3 . 
     Although the state that the rotation amount is set at zero is employed here as the initial state, the invention is not limited this case. For example, the initial state may be a state that the rotational drive unit  10  has rotated the pressing surface  6   b  so that the pressing surface  6   b  comes into uniform contact with the skin according to the shape of the wrist to which the blood pressure measurement device is attached. 
     Upon reception of a blood pressure measurement instruction, the control unit  12  controls the air bag drive unit  11  to start injecting air into the air bag  2  and thereby increases the pressing force that the pressing surface  6   b  exerts toward the radius artery T (step S 1 ). 
     In the process of increasing the pressing force, with certain timing (e.g., periodic timing) after a lapse of a sufficient time from a start of closure of the radius artery T, the control unit  12  acquires plural latest pressure pulse wave information I 1  (pressure pulse waves) that have been detected by the respective pressure sensors  6   a  so far and are stored in the memory  15 . With the certain timing, the control unit  12  acquires plural latest pressure pulse wave information  12  (pressure pulse waves) that have been detected by the respective pressure sensors  7   a  so far and are stored in the memory  15  (step S 1 A). 
     The control unit  12  calculates, for example, an amplitude average value Ave 1  of pressure pulse waves that were detected by the respective pressure sensors  6   a  at time t 1  among the plural pressure pulse wave information I 1  acquired at step  1 A and an amplitude average value Ave 2  of pressure pulse waves that were detected by the respective pressure sensors  6   a  at time t 2  that is later than time t 1 . The control unit  12  also calculates an amplitude average value Ave 3  of pressure pulse waves that were detected by the respective pressure sensors  7   a  at time t 1  among the plural pressure pulse wave information  12  acquired at step  1 A and an amplitude average value Ave 4  of pressure pulse waves that were detected by the respective pressure sensors  7   a  at time t 2 . Then the control unit  12  calculates ratios between the average values calculated at the same time points, that is, Ave 1 /Ave 3  and Ave 2 /Ave 4 . 
     The control unit  12  judges whether to cause the rotational drive unit  10  to rotate the rotary member  5  on the basis of a variation between the ratios calculated the plural time points. That is, the control unit  12  judges whether to rotate the rotary member  5  on the basis of the pressure pulse waves detected by the pressure sensors  6   a  and  7   a  at the plural time points in the process that the pressing force is increased (step S 1 B). 
     For example, if the ratios calculated at the plural time points show monotonic increase, it can be judged that the element array of the pressure sensors  7   a  are located on the side on which the radius artery T is closed and the element array of the pressure sensors  6   a  are not located on that side. Thus, the control unit  12  judges that it is necessary to rotate the rotary member  5 . 
     If the ratios calculated at the plural time points show monotonic decrease, it can be judged that the element array of the pressure sensors  6   a  are located on the side on which the radius artery T is closed and the element array of the pressure sensors  7   a  are not located on that side. Thus, the control unit  12  judges that it is necessary to rotate the rotary member  5 . 
     If the ratios calculated at the plural time points show almost no variation, it can be judged that the two element arrays are detecting pressure pulse waves of the radius artery T in the same manner. Thus, the control unit  12  judges that it is not necessary to rotate the rotary member  5 . 
     If the ratios calculated at plural time points show increase and decrease repeatedly, it cannot be judged whether the radius artery T is pressed sufficiently on the respective sides of the two element arrays or the radius artery T is not pressed sufficiently only on the side of one element array. Thus, the control unit  12  judges that it is not necessary to rotate the rotary member  5 . 
     As described above, the control unit  12  judges whether rotation is necessary on the basis of a variation of the ratios calculated at the plural time points. Instead of the ratios, a difference (a sign is taken into consideration) between the average values Ave 1  (Ave 2 ) and Ave 3  (Ave 4 ) may be used. 
       FIG. 10A  is a diagram for showing an example state that the radius artery T is closed on the side of the element array of the pressure sensors  7   a  but is not closed on the side of the element array of the pressure sensors  6   a . In the state of  FIG. 10A , the distance between the element array of the pressure sensors  6   a  is longer than that between the element array of the pressure sensors  7   a.    
     Let  6 A and  7 A represent an amplitude average value of pressure pulse waves detected by the respective pressure sensors  6   a  and an amplitude average value of pressure pulse waves detected by the respective pressure sensors  7   a , respectively; then, in the state of  FIG. 10 , the ratio  6 A/ 7 A is sufficiently larger than 1. In this state,  6 A/ 7 A comes closer to  1  if the element array of the pressure sensors  6   a  is brought closer to the radius artery T. 
     Thus, if judging at step S 1 B that it is necessary to rotate the rotary member  5  about the rotation axis Y, the control unit  12  performs a control so as to rotate the rotary member  5  about the rotation axis Y according to a  6 A/ 7 A value obtained at the latest time point (step S 1 C). 
     More specifically, the control unit  12  reads out a rotation amount corresponding to the  6 A/ 7 A value by referring to a data table (determined empirically and stored in the memory  15  before shipment of a product) showing a relationship between the  6 A/ 7 A value and the rotation amount of the rotary member  5  and sets the read-out rotation amount. 
     In addition, the control unit  12  judges which of the average value  6 A and the average value  7 A is larger. If the average value  6 A is larger, the control unit  12  sets the rotation direction of the rotary member  5  about the rotation axis Y to counterclockwise in  FIG. 10  to decrease the distance between the element array of the pressure sensors  6   a  and the radius artery T. 
     If the average value  7 A is larger, the control unit  12  sets the rotation direction of the rotary member  5  about the rotation axis Y to clockwise in  FIG. 10  to decrease the distance between the element array of the pressure sensors  7   a  and the radius artery T. 
     The control unit  12  rotates the rotary member  5  in the thus-set rotation direction by the thus-set rotation amount. As a result, as shown in  FIG. 10B , the pressing surface  6   b  can be made parallel with the radius artery T to establish a state that the radius artery T is closed on the respective sides of the two element arrays. 
     The control unit  12  moves to step S 2  after the execution of step S 1 C or after the execution of step S 1 B (if a judgment was made that it is not necessary to rotate the rotary member  5 ). At step S 2 , the control unit  12  judges whether the pressing force has become such as to correspond to a pressure that is enough to close the radius artery T (i.e., has reached a necessary pressing force). If judging that the pressing force has reached a necessary pressing force (step S 2 : yes), the control unit  12  controls the air bag drive unit I 1  to stop the injection of air into the air bag  2  (step S 3 ). If judging that the pressing force has not reached a necessary pressing force yet, the control unit  12  returns to step S 1 A. 
     After the execution of step S 3 , the control unit  12  determines an amplitude distribution curve (what is called a tomogram) indicating a relationship between the amplitude of a pressure pulse wave that was detected by each pressure sensor  6   a  at each time point from step S 1  to step S 3  and the position of the pressure sensor  6   a  in the pressing surface  6   b . The control unit  12  also determines a tomogram indicating a relationship between the amplitude of a pressure pulse wave that was detected by each pressure sensor  7   a  at each time point and the position of the pressure sensor  7   a  in the pressing surface  6   b.    
     The control unit  12  stores the tomogram generated for the element array of the pressure sensors  6   a  in the memory  15  such that it is correlated with identification information of the element array, a detection time of the pressure pulse waves, and a pressing force of the air bag  2  in the pressing direction (an internal pressure of the air bag  2 ) at the detection time. 
     Likewise, the control unit  12  stores the tomogram generated for the element array of the pressure sensors  7   a  in the memory  15  such that it is correlated with identification information of the element array, a detection time of the pressure pulse waves, and a pressing force of the air bag  2  in the pressing direction at the detection time. 
     The control unit  12  calculates a movement distance of the radius artery T in the direction B during the pressing of the pressing surface  6   b  against the wrist using the tomogram data stored in the memory  15  (step S 6 ). 
       FIGS. 11A and 11B  are diagrams for showing examples of amplitude values of pressure pulse waves that are detected by the pressure sensors  6   a  of the sensor unit  6  as the pressing force that the sensor unit  6  exerts on the wrist is varied. In  FIGS. 11A and 11B , the horizontal axis represents the position of the pressure sensor  6   a  in the direction B and the vertical axis represents the pressing force. 
     In  FIGS. 11A and 11B , the amplitudes of the pressure pulse waves detected by the pressure sensors  6   a  located at the respective positions are indicated by different colors according to their magnitudes. 
     Symbol A 1  denotes a region where the amplitude is larger than or equal to a threshold TH 1 . Symbol A 2  denotes a region where the amplitude is larger than or equal to a threshold TH 2  and smaller than the threshold TH 1 . Symbol A 3  denotes a region where the amplitude is larger than or equal to a threshold TH 3  and smaller than the threshold TH 2 . Symbol A 4  denotes a region where the amplitude is larger than or equal to a threshold TH 4  and smaller than the threshold TH 3 . Symbol A 5  denotes a region where the amplitude is smaller than the threshold TH 4 . There is a relationship that (threshold TH 1 )&gt;(threshold TH 2 )&gt;(threshold TH 3 )&gt;(threshold TH 4 ). 
     The example of  FIG. 11A  is such that the positions of pressure sensors  6   a  that detect pressure pulse waves whose amplitudes are larger than or equal to the threshold TH 1  have almost no changes in a process that the pressing force is increased. In contrast, the example of  FIG. 11B  is such that the positions of pressure sensors  6   a  that detect pressure pulse waves whose amplitudes are larger than or equal to the threshold TH 1  shift leftward in a process that the pressing force is increased. 
       FIGS. 12A to 12C  are diagrams for showing how pressing of the sensor unit  6  against the wrist by the air bag  2  proceeds after attachment of the pressure pulse wave detection unit  100  to the wrist. In  FIGS. 12A to 12C , symbol TB denotes the radius and symbol K denotes a tendon. 
     After pressing of the sensor unit  6  against the wrist by the air bag  2  is started as shown in  FIG. 12A , there may occur an event that the radius artery T is moved in the direction B as shown in  FIG. 12B . 
     If the radius artery T is moved in the direction B as shown in  FIG. 12B  during pressing, the distribution of the amplitude values of pressure pulse waves vary as shown in  FIG. 11B  during the pressing. More specifically, there occurs a large difference between the position of a pressure sensor  6   a  that detects an amplitude value that is larger than or equal to the threshold TH 1  first as the pressing force is increased and the position of a pressure sensor  6   a  that detects an amplitude value that is larger than or equal to the threshold TH 1  last. 
     In the example of  FIG. 11A , there is no large difference between the position of a pressure sensor  6   a  that detects an amplitude value that is larger than or equal to the threshold TH 1  first as the pressing force is increased and the position of a pressure sensor  6   a  that detects an amplitude value that is larger than or equal to the threshold TH 1  last. Thus, it is seen that the radius artery T is closed making almost no movement in the direction B in the process that the pressing force is increased. 
     In this manner, a position variation of the radius artery T in the direction B can be detected by checking how the tomogram varies in a process that the pressing force is changed. If the radius artery T is closed by increasing the pressing force while the state of  FIG. 12B  is left as it is, correct tonograms may not be obtained due to influence from living body tissue such as the tendon K. 
     In view of the above, at step S 6 , the control unit  12  calculates a difference (i.e., a movement distance of the radius artery T in the direction B) between the position of a pressure sensor  6   a  that detected an amplitude value that is larger than or equal to the threshold TH 1  first as the pressing force was increased and the position of a pressure sensor  6   a  that detected an amplitude value that is larger than or equal to the threshold TH 1  last on the basis of data as shown in  FIGS. 11A and 11B  that indicate a relationship between the pressing force and the tomogram. And the control unit  12  judges whether the calculated difference is larger than or equal to a threshold THa (step S 7 ). 
     If the difference between the two positions is larger than or equal to the threshold THa (step S 7 : yes), at step S 8  the control unit  12  determines a vector as shown in  FIG. 11B  by an arrow. If the difference between the two positions is smaller than the threshold THa (step S 7 : no), the control unit  12  moves to step S 9 . 
     Information indicating a relationship between the direction and magnitude of a vector as shown in  FIGS. 11A and 11B  and the direction and amount of rotation of the rotary member  5  about the rotation axis X is determined empirically and stored in the memory  15  in advance. 
     The control unit  12  acquires information indicating a rotation direction and amount corresponding to the determined direction and magnitude of the determined vector from the memory  15 , and sends the acquired information to the rotational drive unit  10 . The rotational drive unit  10  rotates the rotary member  5  according to the received information in the manner shown in  FIG. 12C  (step S 8 ). 
     As described above, when receiving a blood pressure measurement instruction, the control unit  12  judges whether it is necessary to rotate the rotary member  5  at steps S 1 B and S 7  on the basis of pressure pulse waves detected by the respective pressure sensors  6   a  and  7   a  at plural time points in the process that the pressing force of the air bag  2  was increased. If judging that it is necessary to rotate the rotary member  5  (step S 1 B: yes; step S 7 : yes), the rotational drive unit  10  rotates the rotary member  5  on the basis of the pressure pulse waves detected by the respective pressure sensors  6   a  and  7   a.    
     At step S 9  which follows step S 8 , the control unit  12  starts decreasing the pressing force acting on the radius artery T by discharging air from the air bag  2 . 
     Upon decreasing the pressing force to a minimum value after the reduction of the pressing force was started at step S 9 , the control unit  12  determines an optimum pressure sensor from among all of the pressure sensors  6   a  and  7   a . For example, the control unit  12  determines, as an optimum pressure sensor, a pressure sensor that detected a pressure pulse wave having a maximum amplitude in the process that the pressing force was decreased. 
     A pressure pulse wave that is detected by a pressure sensor that is located right over a flat portion of the radius artery T is not affected by tension of the wall of the radius artery T and hence exhibits a maximum amplitude. And this pressure pulse wave provides a highest correlation with the blood pressure inside the radius artery T. For these reasons, a pressure sensor that detected a pressure pulse wave having a maximum amplitude is determined as an optimum pressure sensor. 
     Plural pressure sensors may be found that detected pressure pulse waves having a maximum amplitude. In this case, it is appropriate to deal with these plural pressure sensors as optimum pressure sensors and to employ an average, for example, of the pressure pulse waves detected by these respective plural pressure sensors as a “pressure pulse wave detected by an optimum pressure sensor.” 
     The control unit  12  generates pulse wave envelope data using the pressure pulse wave detected by the optimum pressure sensor in the pressing force decreasing process (step S 10 ). 
     The pulse wave envelope data is data that correlates the pressing force (the internal pressure of the air bad  2 ) that the sensor unit  6  exerts toward the radius artery T and the amplitude of the pressure pulse wave that is detected by the optimum pressure sensor in a state that the optimum pressure sensor is pressed toward the radius artery T by this pressing force. 
       FIG. 13  is a graph for showing an example of how a pressure pulse wave detected by an optimum pressure sensor varies as the pressure acting on the wrist is varied. In  FIG. 13 , a straight line that is given a symbol P indicates the pressure and a waveform that is given a symbol M denotes a pressure wave. An enlarged version of a one-beat pressure pulse wave is shown in a bottom part of  FIG. 13 . 
     As shown in  FIG. 13 , pressures at a rising point and a falling point of each pressure pulse wave are referred to as a minimum value Mmin and a maximum value Mmax, respectively. The amplitude of the pressure pulse wave is a difference between the maximum value Mmax and the minimum value Mmin. Each of the maximum value Mmax and the minimum value Mmin is information characterizing the shape of the pressure pulse wave. 
     Upon cancellation of a closed state of the radius artery T after a start of reduction of the pressing force, the amplitude of the pressure pulse wave detected by the optimum pressure sensor increases rapidly. The amplitude thereafter varies as shown in  FIG. 13  as the pressing force decreases. At step S 10 , the control unit  12  generates pulse wave envelope data as shown in  FIG. 14  on the basis of the relationship between the pressing force and the pressure pulse wave as shown in  FIG. 13 . 
     Upon generating the pulse wave envelope data as shown in  FIG. 14 , the control unit  12  calculates SBP and DBP on the basis of the generated pulse wave envelope data (step S 11 ). 
     For example, the control unit  12  determines, as SBP, a pressure at a time point when the pressure pulse wave amplitude starts to rise rapidly in the pulse wave envelope shown in  FIG. 14  after the start of reduction of the pressing force, that is, a pressure at a time point when the pressure pulse wave amplitude detected by the optimum pressure sensor first exceeds a threshold THb for judgment for an end of an artery closed state after the start of reduction of the pressing force. Alternatively, the control unit  12  calculates a difference between two adjacent amplitude values of the pulse wave envelope data and determines, as SBP, a pressure at a time point when the difference exceeds a threshold. 
     Furthermore, the control unit  12  employs, as a pulse pressure (PP), a maximum value of the pressure pulse wave amplitude of the pulse wave envelope shown in  FIG. 14  and calculates DBP using the calculated SBP and PP according to an equation SBP−DBP=PP. 
     After the execution of step S 11 , the control unit  12  generates calibration data to be used in a continuous blood pressure measurement (described later) using a maximum value Mmax and a minimum value Mmin of one (e.g., a pressure pulse wave that had a maximum amplitude) of pressure pulse waves detected by the optimum pressure sensor that was determined in the pressure decreasing process (step S 9 ) and the SBP and DBP calculated at step S 11 . The control unit  12  stores the generated calibration data in the memory  15  (step S 12 ). 
     Relationships 
       SBP= a×M max+ b    (1)
 
       DBP= a×M min+ b    (2)
 
     holds where a and b are a slope and an intercept of a linear function, respectively. 
     The control unit  12  calculates the slope a and the intercept b by substituting the SBP and DBP determined at step S 11  and the maximum value Mmax and the minimum value Mmin of the pressure pulse wave having a maximum amplitude in the pulse wave envelope shown in  FIG. 14  into Equations (1) and (2). The control unit  12  stores the calculated coefficients a and b and Equations (1) and (2) in the memory  15  as calibration data. 
       FIG. 15  is a flowchart illustrating a continuous blood pressure measuring operation in a continuous blood pressure measurement mode of the blood pressure measuring instrument according to the embodiment. 
     After generating calibration data according to the flowchart shown in  FIG. 9 , the control unit  12  controls the air bag drive unit  11  to increase the internal pressure of the air bag  2  and thereby increase the pressing force that the pressing surface  6   b  exerts toward the radius artery T (step S 21 ). 
     Then the control unit  12  determines, as an optimum pressure sensor, one, that detected a pressure pulse wave having a maximum amplitude, of the pressure sensors  6   a  and  7   a  in the process that the pressing force was increased. And the control unit  12  determines, as a pressure corresponding to an optimum pressing force, an internal pressure of the air bag  2  that was produced at a time point of detection of the pressure pulse wave having the maximum amplitude (step S 22 ). 
     Then the control unit  12  restores the initial state by releasing the air from inside the air bag  2  (step S 23 ). The control unit  12  thereafter increases the internal pressure of the air bag  2  to the pressure corresponding to the optimum pressing force determined at step S 22 , and maintains the optimum pressing force (step S 24 ). 
     Subsequently, in a state that the pressing surface  6   b  is pressed toward the radius artery T with the optimum pressing force, at step S 25  the control unit  12  acquires a pressure pulse wave that is detected by the optimum pressure sensor determined at step S 22 . 
     Then, the control unit  12  calculates SBP and DBP by calibrating the acquired one-beat pressure pulse wave using the calibration data that was generated at step S 12  in  FIG. 9 , and causes the display unit  104  to display the calculated SBP and DBP (step S 26 ). 
     More specifically, the control unit  12  calculates SBP by substituting a maximum value Mmax of the pressure pulse wave acquired at step S 25  and the coefficients a and b calculated at step S 12  into the above-mentioned Equation (1) and calculates DBP by substituting a minimum pressure value Mmin of the pressure pulse wave acquired at step S 25  and coefficients a and b calculated at step S 12  into the above-mentioned Equation (2). 
     The control unit  12  stores the pressure pulse wave acquired at step S 25  in the memory such that it is correlated with a time of its acquisition, and calculates, as a pulse rate, the number of pressure pulse waves (stored in the past) per prescribed time (e.g., min). The control unit  12  causes the display  105  to display pulse rhythm corresponding to the calculated pulse rate in the form of information other than a numeral, and causes the display  104  to display the calculated pulse rate (step S 27 ). 
     After the execution of step S 27 , the control unit  12  finishes the process if receiving an instruction to finish the continuous blood pressure measurement (step S 28 : yes), and returns to step S 25  if not receiving an end instruction (step S 28 : no). 
       FIG. 16  shows example displays to be made on the screens of the display units 
     As shown in  FIG. 16 , the SBP (in the illustrated example, “ 110 ”) and the DBP (in the illustrated example, “ 85 ”) that were calculated at step S 26  for each beat and the pulse rate (in the illustrated example, “ 60 ”) calculated at step S 27  are displayed on the display unit  104 . 
     An icon  105 A is displayed on the display unit  105  so as to blink according to the pulse rhythm of the pulse rate calculated at step S 27 . If the pulse rate calculated at step S 27  is “ 60 ,” the icon  105 A blinks 60 times per minute. The control unit  12  causes the display unit  105  to also display information (in the example of  FIG. 16 , date-and-time information) that does not relate to any living body information. 
     As described above, in the blood pressure measuring instrument  200 , in the continuous blood pressure measurement mode, blood pressure values and a pulse rate that are calculated for each beat are displayed only on the display unit  104  and are not displayed on the display unit  105 . Since the display unit  104  is disposed at such a position as to be viewable from the side of the palm of the measurement-subject person, it is hard to see to persons other than the measurement-subject person. This measure thus enables preservation of privacy. 
     On the other hand, in the blood pressure measuring instrument  200 , in the continuous blood pressure measurement mode, the icon  105 A is displayed on the display unit  105  so as to blink according to a pulse rate that is measured at the same time as blood pressure values. Since the display screen of the display unit  105  is located at such a position as to be viewable from the hand back side, the measurement-subject person can see the display unit  105  readily. Furthermore, by looking at the icon  105 A being displayed on the display unit  105 , the measurement-subject person can recognize whether his or her heartbeat is fast or slow. If pressure pulse waves have not been detected, a pulse rate is not calculated and the icon  105 A is not displayed. Thus, by checking the icon  105 A, the measurement-subject person can recognize whether a blood pressure measurement is being made correctly. 
     Persons other than the owner of the blood pressure measuring instrument  200  cannot understand for what purpose the icon  105 A is being displayed, that is, blinking. Thus, even if a third person sees the icon  105 A, the privacy of the measurement-subject person is still preserved. 
     The blood pressure measuring instrument  200  can be provided with a mode in which to measure a blood pressure with desired timing and present it to a user. If this mode is set, the blood pressure measuring instrument  200  can measure a blood pressure in a short time and present it to the user without causing him or her to feel troublesome by the control unit  12 &#39;s executing steps S 1 -S 11  shown in  FIG. 9 . 
     It is expected that in this mode a blood pressure measurement is performed in such a situation that results are not seen by others. Thus, blood pressure values and a pulse rate may be displayed on either the display unit  105  or the display unit  104 . It is therefore preferable for the control unit  12  to select according to a measurement mode and perform a first control for displaying blood pressure values and a pulse rate only on the display unit  104  or a second control for displaying blood pressure values and a pulse rate on both display units  104  and  105 . For example, the control unit  12  may perform the second control in the above-described mode and perform the first control in the continuous blood pressure measurement mode. 
     Where the blood pressure measuring instrument  200  is attached to an inpatient, it is expected that a health care professional measures blood pressure values and a pulse rate with desired timing. In this case, the blood pressure measuring instrument  200  is not high in usability if blood pressure values and a pulse rate are displayed only on the display unit  104 . In view of this, in the case where a health care professional wants to measure blood pressure values and a pulse rate with desired timing, he or she performs a particular manipulation through the manipulation unit  14  and, in response, the control unit  12  performs the second control. 
       FIG. 17  shows example pictures to be displayed on the display units  104  and  105  by the second control. In the examples shown in  FIG. 17 , pieces of information, that is, blood pressure values and a pulse rate measured and a date and time are displayed on each of the display units  104  and  105 . 
     When the second control is performed, it becomes possible to see the same information from both of the palm side and the hand back side of the inpatient. As a result, the health care professional can easily check living body information of the inpatient without the need for changing the posture of the wrist of the inpatient. Furthermore, the inpatient and the health care professional can share the same information easily. As a result, it is expected that the health care professional can, for example, make a conversation with the inpatient about his or her physical condition as part of care using the shared information, which could enhance the quality of medical care. 
     Although the above description is directed to the case that the control unit  12  selects the second control when a blood pressure measurement is performed with desired timing, a configuration is possible in which switching between the first control (i.e., the control for displaying pictures as shown in  FIG. 16 ) and the second control (i.e., the control for displaying pictures as shown in  FIG. 17 ) can be made by a manual manipulation also in the continuous blood pressure measurement mode. 
     As described above, by virtue of the presence of the two display units  104  and  105 , the blood pressure measuring instrument  200  can increase the degree of freedom of selection of a place(s) where to display blood pressure values and a pulse rate as living body information. This provides advantages enhancing the quality of medical care and lowering the burdens of health care professionals and an inpatient while preserving the privacy of the inpatient. 
     Where the first control is performed, information other than living body information can be displayed on the display unit  105 . By causing the display unit  105  to display such an image as an analog watch, this makes it possible to wear the blood pressure measuring instrument  200  in a fashion-oriented manner. This makes it easier to make blood pressure measurement a habit. 
     The blood pressure measuring instrument  200  may be such that it is also equipped with a living body information measuring device other than the pressure pulse wave detection unit  100 , such as a device for measuring a body temperature, a device for measuring a sweat rate, or a device for measuring a percutaneous arterial blood oxygen saturation (SPO 2 ), and that the control unit  12  measures living body information other than blood pressure values and a pulse rate on the basis of information obtained by that device. 
     In this case, it is appropriate that the first control be such as to display living body information that is not desired to be known to others (blood pressure values, pulse rate, body temperature, sweat rate, or oxygen saturation) only on the display unit  104 . It is appropriate that the second control be such as to display blood pressure values, a pulse rate, a body temperature, a sweat rate, or an oxygen saturation on each of the display units  104  and  105 . 
     The control unit  12  may acquire information other than blood pressure values and a pulse rate from an outside device through a wireless or wired communication and display it on the display units  104  and  105 . In these modifications, the control unit  12  functions as a living body information acquiring unit for acquiring information other than living body information that is measured on the basis of detection information of the pressure pulse wave detection unit  100 . 
     Whereas the blood pressure measuring instrument  200  shown in  FIG. 1  is configured such that the display units  104  and  105  are provided independently of each other, the display units  104  and  105  may be integrated with each other. 
       FIG. 18  is a side view showing a modification of the blood pressure measuring instrument  200 . The body of the blood pressure measuring instrument is a C-shaped body  110  which is made of a material that enables deformation into a wrist-mountable shape. The body  110  is configured so as to be able to form a space Ka into which a wrist H can be inserted. 
     The outer circumferential surface of the body  110  is formed with a curved display  107  which extends from the palm side to the hand back side in a state that the blood pressure measuring instrument is attached to the wrist. 
     In the curved display  107 , an area having a prescribed size and centered at point P 1  that is closer to the palm than the center of the space Ka is in the direction D between two points P 1  and P 2  where a straight line (e.g., a straight line L 2  shown in  FIG. 18 ) passing through the space Ka intersects the outer circumferential surface in  FIG. 18  functions as the display unit  104 . And an area having a prescribed size and centered at point P 2  that is closer to the back of the hand than the center of the space Ka is in the direction D functions as the display unit  105 . The configuration shown in  FIG. 18  can also provide the same advantages as the blood pressure measuring instrument  200  does. 
     The processes shown in  FIGS. 9 and 15  which are executed by the control unit  12  can be implemented as programs for causing a computer to execute their individual steps. Such programs are recorded in a computer-readable, non-transitory recording medium. 
     Such a computer-readable recording medium includes an optical medium such as a CD-ROM (compact disc-ROM) and a magnetic recording medium such as a memory card. It is also possible to provide such programs by downloading them over a network. 
     The embodiment disclosed above should be construed in all respects as being illustrative and not being restrictive. The scope of the invention is defined by the claims rather than the above description, and it is intended that the scope of the invention includes all changes that are within the range of the claims and their equivalents. 
     For example, the method for calculating SBP and DBP for each beat and the configuration of the pressure pulse wave detection unit  100  are not limited to those described above and may be known ones as disclosed in JP-2004-113368-A, JP-H02-261421-A, JP-H07-124130-A and JP-H01-242031-A. 
     Although the blood pressure measuring instrument  200  measures living body information on the basis of pressure pulse waves detected directly from a wrist by the pressure pulse wave detection unit  100 , a configuration may be employed in which a living body signal is detected indirectly as in known wrist sphygmomanometers. 
     More specifically, a configuration is possible in which pressure pulse waves are detected as a living body signal using pressure control unit for controlling a pressure that a cuff exerts on a wrist and a pressure sensor for detecting an inner pressure of the cuff and a blood pressure is measured by a known oscillometric method. Another configuration is possible in which a blood flow sound (Korotkoff sound) is detected as a living body signal using a microphone instead of a pressure sensor and living body information including a blood pressure and a pulse rate is measured from the blood flow sound. 
     As described above, the following items are disclosed in this specification. 
     The disclosed living body information measuring instrument is a wrist-mounted living body information measuring instrument having a living body information measuring unit for measuring living body information on the basis of a living body signal detected from a wrist, including a main body which forms a space into which the wrist can be inserted; a first display unit and a second display unit which are provided on an outer circumference of the main body; and a display control unit which performs display controls on the first display unit and the second display unit, wherein the first display unit and the second display unit are disposed such that the space exists on a straight line that connects a center of a display screen of the first display unit and a center of a display screen of the second display unit, and a center of the space is located between the center of the display screen of the first display unit and the center of the display screen of the second display unit in a direction that is perpendicular to a palm in a state that the living body information measuring instrument is attached to the wrist. 
     The disclosed living body information measuring instrument further includes a pressure detection unit; and a pressing unit which presses the pressure detection unit toward an artery that runs under a skin of the wrist, wherein the living body information measuring unit measures living body information on the basis of pressure pulse waves detected as a living body signal by the pressure detection unit in a state that the pressure detection unit is pressed toward the artery by the pressing unit. 
     In the disclosed living body information measuring instrument, the display control unit causes the first display unit and the second display unit to display information that is based on the living body information measured by the living body information measuring unit. 
     In the disclosed living body information measuring instrument, the center of the display screen of the first display unit is closer to the palm than the center of the space in the direction that is perpendicular to the palm; the center of the display screen of the second display unit is closer to a back of a hand than the center of the space in the direction that is perpendicular to the palm; and the display control unit causes the second display unit to display, as the information based on the living body information, information for notification of pulse rhythm that is measured on the basis of the pressure pulse waves as the living body signal, and causes the first display unit to display, as the information based on the living body information, blood pressure values that are measured on the basis of the pressure pulse waves. 
     In the living body information measuring instrument, the display control unit selectively performs a first control for displaying different pieces of information on the first display unit and the second display unit and a second control for displaying the same information on the first display unit and the second display unit. 
     In the disclosed living body information measuring instrument, the center of the display screen of the first display unit is closer to the palm than the center of the space in the direction that is perpendicular to the palm; the center of the display screen of the second display unit is closer to a back of a hand than the center of the space in the direction that is perpendicular to the palm; the first control is a control for causing the second display unit to display, as the information based on the living body information, information for notification of pulse rhythm that is measured on the basis of the pressure pulse waves as the living body signal, and causing the first display unit to display, as the information based on the living body information, blood pressure values that are measured on the basis of the pressure pulse waves; and the second control is a control for causing each of the first display unit and the second display unit to display, as the information based on the living body information, at least blood pressure values that are measured on the basis of the pressure pulse waves among the blood pressure values and a pulse rate that is measured on the basis of the pressure pulse waves. 
     In the disclosed living body information measuring instrument, the center of the display screen of the first display unit is closer to the palm than the center of the space in the direction that is perpendicular to the palm; the center of the display screen of the second display unit is closer to a back of a hand than the center of the space in the direction that is perpendicular to the palm; the living body information measuring instrument further includes a living body information acquiring unit which acquires living body information other than the living body information measured by the living body information measuring unit; and the information that the display control unit causes the first display unit to display includes the living body information acquired by the living body information acquiring unit. 
     The invention can provide a living body information measuring instrument which allows both of a measurement-subject person and a third person to check measured living body information easily by giving a higher degree of freedom to the manner of display of measured living body information and enables consideration for preservation of the privacy of the measurement-subject person. 
     Although the invention has been described above using the particular embodiment, the invention is not limited to this embodiment. Various modifications are possible without departing from the technical concept of the disclosed invention.