Abstract:
A detecting apparatus for detecting a living body information includes a sensor body provided to contact a surface of a living body, and a band fixing bar elongated in a longitudinal direction, through which a band is engaged and is detachably connectable to the sensor body. In the detecting apparatus, the sensor body has a pair of holding portions for holding end portions of the band fixing bar in the longitudinal direction. The holding portion has an inlet concave portion from which the end portion of the band fixing bar is inserted, and a recess portion for receiving the end portion of the band fixing bar. Furthermore, the recess portion communicates with the inlet concave portion and recesses toward the living body, and the end portion of the band fixing bar is fitted into the recess portion. Therefore, the band fixing bar does not easily come off from the sensor body.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application is based on Japanese Patent Application No. 2005-142939 filed on May 16, 2005, the contents of which are incorporated herein by reference in its entirety.  
       FIELD OF THE INVENTION  
       [0002]     The present invention relates to a mounting structure with a band fixing bar. More particularly, the present invention relates to a band fixing bar mounting mechanism and an apparatus using the same, which can be suitably used for a pulse wave sensor for detecting pulse waves, for example.  
       BACKGROUND OF THE INVENTION  
       [0003]     A conventional wrist watch type pulse wave sensor for detecting a pulse rate by using a reflective optical apparatus has been known (JP-A-2001-78972). In the pulse wave sensor, a wrist band is attached to a sensor body having the reflective optical apparatus therein. The sensor body is fitted to a wrist by winding the band around the wrist and making the band stay around the wrist with a hook.  
         [0004]     However, in the above-described structure, the band is fixed to the sensor body by using a spring bar bent in an axial direction thereof, which is manufactured for wrist watches. Therefore, an attachment/detachment of the wrist band to/from the sensor body is difficult, especially at the time of detachment.  
         [0005]     Furthermore, since a structure of the spring bar is complicated, it has pushed up manufacturing cost thereof.  
       SUMMARY OF THE INVENTION  
       [0006]     In view of the above-described problems, it is an object of the present invention to provide a mounting structure with a band fixing bar, which can prevent the band fixing bar from being easily removed after an attachment while a band can be easily attached to or detached from a sensor body.  
         [0007]     It is another object of the present invention to provide a detecting apparatus for detecting a living body information with the mounting structure.  
         [0008]     According to an aspect of the present invention, a mounting structure includes an apparatus held by a band to contact a surface of a living body, a band fixing bar elongated in a longitudinal direction, through which the band is engaged and is detachably connectable to the apparatus, and a pair of holding portions provided in the apparatus, for holding end portions of the band fixing bar in the longitudinal direction. The holding portion has an inlet concave portion from which the end portion of the band fixing bar is inserted, and a recess portion for receiving the end portion of the band fixing bar. In the mounting structure, the recess portion communicates with the inlet concave portion and recesses from an end of the inlet concave portion toward the living body, and the end portion of the band fixing bar is fitted into the recess portion. Accordingly, the band fixing bar does not easily come off from the apparatus, when the apparatus is attached to a human.  
         [0009]     The band fixing bar can have an elasticity to be bendable in a radial direction approximately perpendicular to the longitudinal direction. In this case, a protruding portion can be located between the holding portions in the axial direction, and the protruding portion protrudes from the apparatus to the living body at an outer position of the band fixing bar in the radial direction so as to prevent the band fixing bar from falling. In this case, it can further prevent the band fixing bar from being removed. The protruding portion can be provided with a lowest point on a side of the living body to contact the band fixing bar when the band fixing bar is inserted into the inlet concave portion. For example, the protruding portion can be provided approximately in a middle area of the holding portions, or can be constructed with a plurality of convex portions separate from each other in the axial direction of the band fixing bar.  
         [0010]     Furthermore, the recess portion of the apparatus can be set at a lowest point on a side of the living body, and the lowest point can be made lower than a lower end of the inlet concave portion in a state where the apparatus is positioned above the surface of the living body. In this case, the band fixing bar fitted into the recess portion is not easily come off from the inlet concave portion. In addition, a maximum width between the inlet concave portions of the holding portions can be set greater than a dimension of the band fixing bar in the longitudinal direction.  
         [0011]     The holding portions can be provided at an inner side from an outer periphery of the apparatus in the longitudinal direction. Furthermore, the holding portions can be provided so that the band fixing bar mounted to the holding portions is covered by the apparatus when viewed from an opposite direction with respect to the living body.  
         [0012]     Furthermore, a trench portion recessed from an outer wall of the apparatus can be provided so that a bar part of the band fixing bar between the end portions is located in the trench portion. For example, the band fixing bar has a shape of a circular cylinder, a rectangular prism or a hexagonal prism elongated in the longitudinal direction.  
         [0013]     According to another aspect of the present invention, the band fixing bar can be provided with at least one convex portion protruding from one end surface of the band fixing bar in the longitudinal direction. In this case, a thickness of the convex portion is made smaller than a thickness of the band fixing bar, the inlet concave portion has an open shape corresponding to a sectional shape of the convex portion with the thickness, and the convex portion is provided to pass through the inlet concave portion in a predetermined direction. Accordingly, the band can be easily attached to or detached from the apparatus, while it can prevent the band fixing bar from removing when using the apparatus.  
         [0014]     The mounting structure can be suitably used for a detecting apparatus for detecting a living body information. For example, the band has a loop at each end and the band fixing bars are inserted into the loops. By connecting the band fixing bars having the band to a sensor body, the band is attached to the sensor body. Therefore, the bar hardly comes off from sensor body once mounted. A measurement part of the sensor body can detect human body information by winding the band around an arm or a wrist. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments made with reference to the accompanying drawings, in which:  
         [0016]      FIG. 1  is a schematic diagram illustrating a pulse wave sensor in a first embodiment of the present invention;  
         [0017]      FIGS. 2A  to  2 C are perspective views of bars which can be used as a band fixing bar;  
         [0018]      FIG. 3  is a schematic diagram illustrating an elasticity of the band fixing bar;  
         [0019]      FIG. 4  is a schematic sectional view illustrating a band in its straightened state;  
         [0020]      FIGS. 5A and 5B  are side views of a sensor body of the sensor in  FIG. 1  viewed from an arrow A;  
         [0021]      FIG. 6A  is a schematic cross-sectional view of the sensor body taken along the line B-B in  FIG. 5A , and  FIG. 6B  is a schematic diagram illustrating a vicinity of a holding portion in  FIG. 5A ;  
         [0022]      FIGS. 7A and 7B  are cross-sectional views of the sensor body taken along the line B-B in  FIG. 5A ;  
         [0023]      FIG. 8  is a schematic diagram illustrating another example in which plural convex portions are used;  
         [0024]      FIG. 9A  is a perspective view of a band fixing bar used for a pulse wave sensor in a second embodiment of the present invention, and  FIG. 9B  is a schematic diagram illustrating a vicinity of a mounting mechanism of a sensor body when viewed from an axial direction of the band fixing bar; and  
         [0025]      FIG. 10 A  is a side view of a sensor body in a third embodiment of the present invention, and  FIG. 10B  is a schematic diagram showing a relation of a band fixing bar and a band in  FIG. 10A . 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0026]     Embodiments of the present invention will be described with reference to accompanying drawings.  
       First Embodiment  
       [0027]     A living body information detecting apparatus, e.g., a pulse wave sensor, for optically detecting a pulse wave by attaching the apparatus closely to an arm of a human body will be described as an example. A basic structure of the pulse wave sensor will be described referring to  FIG. 1  through  FIG. 4   
         [0028]     A pulse wave sensor  1  is a portable apparatus, which can be attached to e.g., a human arm  3  as shown in  FIG. 1 . The pulse wave sensor  1  includes a sensor body  7  having a measurement part  5  that measures a pulse wave optically, a strip-shaped band  9  for attaching the sensor body  7  to the arm  3 , and band fixing bars  11 ,  13  (shown in  FIG. 4 ) for attaching the band  9  to the sensor body  7 .  
         [0029]     Although not shown, the measurement part  5  is constructed of a green light-emitting diode (a green LED), an infrared-emitting diode (an IRED) and a photodiode (a PDIO). The PDIO receives reflected lights of the green LED and IRED. The green LED is for detecting the pulse wave by emitting the green light to the human body and detecting changes in an amount of hemoglobin of blood capillaries from its reflected light. The IRED is for detecting body movement by emitting the infrared light to the human body and detecting the body movement from its reflected light.  
         [0030]     The sensor body  7  is an approximately rectangular and plate-shaped apparatus having an indicator and switches (neither shown) on an upper surface thereof. The measurement part  5  is provided on a back surface of the sensor body  7 , which closely contacts a surface of the arm  3 .  
         [0031]     The band fixing bar  11  is, for example, a cylinder with diameter of 2 mm and length 33 mm as shown in  FIG. 2A . The diameter of the bar  11  is uniform in an axial direction thereof. The band fixing bar  11  is made of resinous material like an acrylic resin. As shown in  FIG. 3 , when pushed with a finger, the bar  11  bends in the radial direction thereof (perpendicular with respect to the axial direction of the bar  11 ) and bends back to a normal state when the pressure thereon is removed.  
         [0032]     The shape of the band fixing bar  11  can be a rectangular prism as shown in  FIG. 2B  or a hexagonal prism as shown in  FIG. 2C . The material is not necessarily limited to the acrylic resin but can be other resinous materials such as polycarbonate. Metals can be used for the bar likewise. It is more cost effective if a singular material is used for the band fixing bar  11 .  
         [0033]     The band  9  is made of rubber or circular-knitted fabric having an elasticity. The ends of the band  9  are made into loops having through holes  15 ,  17  for receiving the band fixing bars  11 ,  13 . The band fixing bars  11 ,  13  are inserted into the through holes  15 ,  17  of the band  9 , respectively.  
         [0034]     Therefore, by attaching the band fixing bars  11 ,  13  to mounting mechanisms  19 ,  21  provided at two ends of the sensor body  7 , the band  9  can be attached to the sensor body  7 .  
         [0035]     The band  9  and the sensor body  7  form a ring shape so that the arm  3  can be put through the ring. The pulse wave sensor  1  can be fitted to the arm  3  after being attached, since the band  9  has the elasticity.  
         [0036]     Next, a structure and a method of mounting the band fixing bars  11 , 13  to the sensor body  7  will be described referring to  FIG. 5A  through  FIG. 7B .  
         [0037]      FIGS. 5A and 5B  are side views of the sensor body  7  viewed from an arrow A in  FIG. 1 .  FIGS. 6A, 7A  and  7 B are cross-sectional views of the mounting mechanism of the sensor body  7  taken along the line B-B in  FIG. 5A . As shown in  FIG. 5A , the mounting mechanism  19  for receiving the band fixing bar  11  is provided at a down corner of the sensor body  7 , which is at a side of the sensor body  7  facing the living body (i.e., arm  3 ). Here, the mounting mechanism  21  has the same structure as in the mechanism  19 , the following explanation will be given to the mechanism  19 .  
         [0038]     The mounting mechanism  19  has a long trench portion  23  that is provided in a center area on a side back surface of the mechanism  19  in a left-right direction of  FIG. 5A . Holding portions  25 ,  27  for holding the band fixing bar  11  are provided, respectively, at ends of the trench portion  23 . The left-right direction corresponds to the axial direction of the band fixing bar  11  when attached to the mounting mechanism  19 .  
         [0039]     Inlet concave portions  29 ,  31 , each of which has a rectangular shape of 2.1 mm long and 2 mm and opens towards front in  FIG. 5A , are provided at the holding portions  25 ,  27 . The left and right ends of the band fixing bar  11  fit respectively into the inlet concave portions  29 ,  31 .  
         [0040]     A length W 2  of the trench portion  23  in the left-right direction is set as 30 mm, for example, which is shorter than a length W 1  of the band fixing bar  11  as shown in  FIG. 5B . A length W 3 , which is a dimension including the length of the trench portion  23  and the inlet concave portions  29 ,  31 , is set as 34 mm for example, to be longer than the length W 1  of the band fixing bar  11 .  
         [0041]     Notched recess portions  33 ,  35  shown in  FIG. 5A  are provided further inward from the inlet concave portions  29 ,  31  to a side of a center part of the sensor body  7 . The notched recess portions  33 ,  35  are provided in the sensor body  7  to the side of the arm (in the lower direction of  FIG. 6A ). Therefore, the both ends of the band fixing bar  11  inserted from the inlet concave portions  29 , 31  fall into the notched recess portions  33 ,  35  to be held therein as shown in  FIG. 6A  and  FIG. 6B .  
         [0042]     As shown in  FIGS. 5A, 5B , a convex portion  37  (indicated with diagonal lines in  FIG. 5A ) for preventing the band fixing bar  11  from coming off from the mechanism  19 , is provided at a middle of the trench portion  23  in the left-right direction. The convex portion  37  protrudes downward from a top surface above the trench portion  23  to have a protruding part protruding into the trench portion  23 . As shown in  FIGS. 5A, 5B , the protruding part has substantially a rectangular section.  
         [0043]     As shown in  FIG. 7A , a lower end (a lowest point) of the convex portion  37  is set to be lower than an upper end of the band fixing bar  11  when the bar  11  is to be fitted into the inlet concave portions  29 ,  31 . Therefore, once the bar  11  is fitted into the inlet concave portions  29 ,  31  by passing the convex portion  37 , the bar  11  does not easily come off from the inlet concave portions  29 , 31  to an outside.  
         [0044]     A lowest point t 2  of the recess portions  33 , 35  is set lower than a lowest point t 1  of the inlet concave portions  29 , 31 , as shown in  FIG. 7B . The lowest point t 1  is also set higher than an axial center point of the band fixing bar  11  fitted into the inlet concave portions  29 ,  31 .  
         [0045]     The inlet concave portions  29 , 31  as well as an inner circumferential surface of the recess portions  33 , 35  at a farther inner area therefrom are formed higher than the center trench portion  23  so that a stepping portion  39  is formed therebetween. A space  41  having a width W 4  is formed between a wall surface  23   a  of the center trench portion  23  and the band fixing bar  11 . The band  9  is fitted to the band fixing bar  11  by making use of the space  41 .  
         [0046]     In this embodiment, the band fixing bar  11  is bendable in the radial direction so as to pass the convex portion  37  and to be inserted into the left and right inlet concave portions  29 , 31 . As a result, the bar  11  is fitted into the left and right recess portions  33 ,  35 . Therefore, the bar  11  is attached to the holding portions  25 ,  27  thereby the band  9  can be attached to the sensor body  7 .  
         [0047]     According to the first embodiment of the present invention, the attachment and removal of the band  9  becomes easy. Since the structure of the band fixing bar  11  is simple, a production cost thereof can be kept low.  
         [0048]     Also, the lower end of the convex portion  37  is set to become lower than the upper end of the band fixing bar  11  (the upper end of an opening of the inlet concave portions  29 ,  31 ) when the bar  11  is fitted into the inlet concave portions  29 ,  31 . Therefore, if the band fixing bar  11  is pulled toward an outer direction (e.g., toward the inlet concave portions  29 ,  31 ), the band fixing bar  11  hits against the convex portion  37 . Thus, the bar  11  hardly comes off to the outside. In addition, because the ends of the band fixing bar  11  are fitted into the recess portions  33 ,  35 , the bar  11  does not easily come off to the outside.  
         [0049]     Also, in this embodiment, the holding portions  25 ,  27  do not protrude from the sensor body  7  to the outer direction. The holding portions  25 ,  27 , the recess portions  33 ,  35  and the band fixing bar  11  are all located inside the outer periphery of the sensor body  7 . Therefore, when viewed from the outside of the sensor body  7 , an exterior looks smooth, since there is few irregularities found on the surface of the sensor body  7 . Also, this structure hardly produces a space between the sensor body  7  and the arm  3 , the sensor body  7  fits closely to the surface of the arm  3 . Therefore, an accuracy in measurement by an optical means also improves.  
         [0050]     As shown in  FIG. 8 , a plurality of convex portions  37   a,    37   b  for preventing the band fixing bar  11  from coming off from the mechanism  19  can be provided above the trench portion  23  side by side in the left-right direction. In this case, when the both ends of the band fixing bar  11  are fitted into the left and right inlet concave portions  29 , 31 , the band  11  needs to be more bent in the radial direction when the band fixing bar  11  is fitted into the inlet concave portions  29 , 31  by passing the single convex portion  37 . Therefore, when the band fixing bar  11  is pulled outwardly (e.g., to the side of the inlet concave portions  29 , 31 ), the bar  11  is more effectively prevented from falling out from the inlet concave portions  29 , 31 .  
       Second Embodiment  
       [0051]     Next, the second embodiment according to the present invention will be described with reference to  FIGS. 9A and 9B . Explanations on the same components as in the first embodiment will be omitted. In this embodiment, a pulse wave sensor has substantially cuboid plate like convex portions  53  at both ends of a cylindrical band fixing bar  51  in the axial direction thereof, as shown in  FIG. 9A .  
         [0052]     A sensor body  55  has a mounting mechanism  57  and an inlet concave portion  59  is provided in the mechanism  57 . A dimension of an opening portion  59   a  of the inlet concave portion  59  is formed smaller than a diameter of a cylindrical part of the band fixing bar  51 .  
         [0053]     To be specific, a dimension L 2 , which is a thickness of the convex portion  53 , is so set that the convex portion  53  can be inserted along its longitudinal direction, when the band fixing bar  51  is fitted into the inlet concave portion  59 .  
         [0054]     An up-down dimension L 1  of the opening portion  59   a  is set almost same as the dimension L 2  or slightly larger than the dimension L 1 .  
         [0055]     Therefore, once the band fixing bar  51  passes through the opening portion  59   a  of the inlet concave portion  59  and is received by a recess  61 , the bar  51  does not come off to an outside easily even when the bar  51  is pulled towards the outside. In the second embodiment, the other parts can be made similar to the above-described first embodiment.  
       Third Embodiment  
       [0056]     The third embodiment according to the present invention will be described. Explanations on the same components as in the first embodiment will be omitted. As shown in  FIG. 10A , when an elastic material is used for a band  71 , the band  71  having a width W 5 , which is greater than a width W 1  of a band fixing bar  73  in an axial direction, can be used.  
         [0057]     Also, as schematically shown in  FIG. 10B , the width of the band  71  in a vicinity of the bar  73  is made narrower so that the band fixing bar  73  can be easily fitted into holding portions  75 ,  77 .  
         [0058]     The larger the width of the band  71  becomes, the more stable the band  71  stays around an arm when it is worn. As a result, an accuracy in measurement also improves.  
         [0059]     While the invention has been described with reference to preferred embodiments thereof, it is to be understood that the invention is not limited to the preferred embodiments and constructions.  
         [0060]     For example, in the above described embodiments, the mounting mechanism of the sensor body has both the convex portions for preventing the fixing bar from coming off and the recess portions for receiving the bar. However, by providing either the convex portions or the recess portions, the mechanism still has enough holding effect. In case only the recess portions are provided, the band fixing bar having non-elasticity can be used.  
         [0061]     Also, when non-elastic material is used for the band, a length of the band is preferably adjusted in accordance with a dimension of an arm.  
         [0062]     In the third embodiment, the other parts can be made similar to those of the first or second embodiment.  
         [0063]     The invention is intended to cover various modification and equivalent arrangements. In addition, while the various elements of the preferred embodiments are shown in various combinations and configurations, which are preferred, other combinations and configuration, including more, less or only a single element, are also within the spirit and scope of the invention.