TECHNICAL FIELD 
     The present invention relates to a biological sample measurement device for measuring biological samples for blood glucose levels, lactic acid levels and/or the like, and a biological sample measurement sensor to be used in the measurement device. 
     BACKGROUND ART 
     Conventional biological sample measurement devices are composed of, for example, a main body case, a connector which is disposed in the main body case for attachment of a biological sample measurement sensor, and a barcode reader (see PTL 1). The conventional biological sample measurement device is configured to read a barcode displayed on a biological sample measurement sensor connected to the connector by means of a barcode reader for the determination of the type of the biological sample measurement sensor, and conduct biological sample measurement that is unique to the biological sample measurement sensor. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1 
         Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2002-521692 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     The barcode reader that reads the type of a biological sample measurement sensor requires a mechanism that scans light and a mechanism that reads information of the scanned light. Accordingly, the cost of a biological sample measurement device including a barcode reader tends to be high. In this respect, the present invention aims to reduce the cost of biological sample measurement devices by providing a novel technique for easily and accurately determining the types of biological sample measurement sensors. 
     Solution to Problem 
     In order to achieve the foregoing object, the present invention provides a biological sample measurement device including: a main body case; a sensor insertion port that is disposed in the main body case and used for inserting a biological sample measurement sensor; a connector that is disposed in the main body case and to which the biological sample measurement sensor is to be attached; a light-emitting element and a light-receiving element that are disposed in the vicinity of the connector in the main body case; and a connector terminal that is disposed in the main body case and can be connected to a connection terminal section of the biological sample measurement sensor attached to the connector. The light-emitting element can emit light to the biological sample measurement sensor to be attached to the connector, and the light-receiving element can receive light reflected from or transmitted through the biological sample measurement sensor to be attached to the connector. Based on the light received and recognized by the light-receiving element, the type of the biological sample measurement sensor is determined. With this configuration, the intended purpose is accomplished. 
     Advantageous Effects of Invention 
     As described above, in the biological sample measurement device of the present invention, the light-receiving element receives light reflected from or transmitted through the biological sample measurement sensor attached to the connector, whereby the type of the biological sample measurement sensor can be determined. This eliminates the need to provide means for scanning light and/or means for reading the scanned light, which have been employed in the art. Consequently, it is possible to reduce the cost of the biological sample measurement device. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing the exterior of a biological sample measurement device; 
         FIG. 2  is an exploded perspective view of the biological sample measurement device; 
         FIG. 3  is an exploded perspective view of a biological sample measurement sensor to be attached to the biological sample measurement device; 
         FIG. 4  is a cross-sectional view of the biological sample measurement sensor to be attached to the biological sample measurement device; 
         FIG. 5  is a plan view of the biological sample measurement sensor to be attached to the biological sample measurement device, the biological sample sensor having no cover provided thereon; 
         FIGS. 6A to 6C  show examples of a pattern of a connection terminal section of the biological sample measurement sensor to be attached to the biological sample measurement device; 
         FIG. 7  is a main part cross-sectional view of the vicinity of a connector of a biological sample measurement device of Embodiment 1; 
         FIG. 8  is an electrical block diagram of the biological sample measurement device of Embodiment 1; 
         FIG. 9  is a flowchart of a measurement performed by the biological sample measurement device of Embodiment 1; 
         FIGS. 10A to 10C  show biological sample measurement sensors having a colored section, which is to be attached to the biological sample measurement device of Embodiment 1; 
         FIG. 11  is a main part cross-sectional view of the vicinity of a connector of a biological sample measurement device of a modified example of Embodiment 1; 
         FIG. 12  is a main part cross-sectional view of the vicinity of a connector of a biological sample measurement device of Embodiment 2; 
         FIG. 13  is an electrical block diagram of the biological sample measurement device of Embodiment 2; 
         FIG. 14  is a flowchart of measurement performed by the biological sample measurement device of Embodiment 2; 
         FIGS. 15A to 15S  show biological sample measurement sensors having a light-transmissive section, which is to be attached to the biological sample measurement device of Embodiment 2; and 
         FIG. 16  is a main part cross-sectional view of the vicinity of a connector of a biological sample measurement device of a modified example of Embodiment 2. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Biological Sample Measurement Device 
     A biological sample measurement device of the present invention includes a main body case, a sensor insertion port, a connector, a light-emitting element, a light-receiving element, and a connector terminal. 
       FIG. 1  is a top perspective view showing the exterior of an example of the biological sample measurement device. As shown in  FIG. 1 , biological sample measurement device  100  includes main body case  1 , display section  4 , power switch  5 , scroll switch  6  for scrolling the contents to be displayed on display section  4 , and sensor insertion port  7 . Display section  4  displays a measurement result and/or the like. Power switch  5  is a switch for turning on or off the power of the measurement device. Through sensor insertion port  7 , a biological sample measurement sensor can be inserted into main body case  1 . 
       FIG. 2  is an exploded perspective view of biological sample measurement device  100 . Main body case  1  is composed of top cover  2  and bottom cover  3 . Display section  4  is disposed on the top surface of top cover  2 , and power switch  5  and scroll switch  6  for scrolling the contents to be displayed on display section  4  are disposed in front of display section  4 . In addition, sensor insertion port  7  is disposed in front of scroll switch  6 . Battery  8  as a power source is stored in bottom cover  3 . 
     Liquid crystal display element  9  is disposed between top cover  2  and bottom cover  3  and displays information on display section  4 . Moreover, control board  10  is disposed in front of liquid crystal display element  9 . Connector  11  is disposed on control board  10 , and a biological sample measurement sensor inserted through sensor insertion port  7  is attached to connector  11 . 
     Connector  11  disposed in the main body case is an attachment section for attaching a biological sample measurement sensor to biological sample measurement device  100 . When a biological sample measurement sensor is attached to connector  11 , a connector terminal of connector  11  is electrically connected to a connection terminal section of the biological sample measurement sensor (see  FIGS. 7 and 12 ). 
     A light-emitting element and a light-receiving element are disposed in the vicinity of connector  11 . The light-emitting element is not particularly limited, and it is, for example, an LED light-emitting element. The biological sample measurement sensor attached to connector  11  is irradiated with light emitted from the light-emitting element. 
     The light-receiving element receives 1) light which is emitted from the light-emitting element and then reflected from the biological sample measurement sensor (see  FIG. 7 ), or 2) light which is emitted from the light-emitting element and then passes through the biological sample measurement sensor (see  FIG. 12 ). The biological sample measurement device of the present invention is characterized by determining the type of a biological sample measurement sensor based on the light received by the light-receiving element. 
     In a first specific embodiment (see Embodiment 1), at least a portion of the biological sample measurement sensor is formed in advance to have a colored section (see  FIG. 10 ), so that the light emitted from the light-emitting element is applied to the colored section and the light reflected from the colored section is received by a color sensor ( FIG. 7 ). In a second specific embodiment (see Embodiment 2), a light-transmissive section is disposed in advance in the biological sample measurement sensor (see  FIG. 15 ), so that light from the light-emitting element passes through the light-transmissive section and the light passed through the light-transmissive section is received by a photodiode (see  FIG. 12 ). 
     [Biological Sample Measurement Sensor] 
     The biological, sample measurement sensor of the present invention electrochemically measures, for example, a substrate in a biological sample. For example, the biological sample measurement sensor measures blood glucose level or lactic acid level. 
       FIGS. 3 to 5  show an example of biological sample measurement sensor  200 .  FIG. 3  is an exploded perspective view of biological sample measurement sensor  200 ;  FIG. 4  is a cross-sectional view of biological sample measurement sensor  200 ; and  FIG. 5  is a plan view showing biological sample measurement sensor  200  without cover  210 . As shown in  FIGS. 3 to 5 , biological sample measurement sensor  200  is a plate-like member. 
     As shown in  FIG. 5 , biological sample measurement sensor  200  includes biological sample inlet  30  disposed at one end of the sensor for injection of a biological sample by landing a droplet of the sample on the inlet, and connection terminal section  40  (where an electrode terminal is disposed) disposed at the other end of the sensor. As shown in  FIG. 3 , biological sample measurement sensor  200  includes cover  210 , spacer  220 , and sensor base  230 . 
     Sensor base  230  includes a patterned metal film deposited thereon, the metal film constituting working electrode  41 , counter electrode  42 , and detection electrode  43 . Detection electrode  43  may not be provided. In addition to working electrode  41 , counter electrode  42 , and detection electrode  43 , a Hct (hematocrit) electrode for measuring a hematocrit level can also be disposed to constitute a quadruple-electrode structure. 
     Specifically, a metal film as a conductive layer (not shown in the drawing) having an approximately uniform thickness is formed on the surface of sensor base  230 . The respective electrodes may be formed on sensor base  230  by forming patterns by means of printing techniques using a conductive material. Alternatively, the electrode patterns may be formed by forming non-conductive tracks by laser ablation or the like of a conductive material (metal film) deposited on the surface of sensor base  230 . For the material constituting the conductive layer, palladium, gold, platinum, carbon, and the like are preferable, with palladium being particularly preferable. For example, a conductive layer is formed by deposition of a film of palladium on the surface of sensor base  230  by sputtering, followed by formation of non-conductive tracks by laser ablation to form patterns of electrode. The width of the non-conductive track is preferably 0.01 mm to 0.5 mm, and more preferably 0.05 mm to 0.3 mm. 
     The thickness of the conductive layer formed on the surface of sensor base  230  can be changed according to the formation method and the constituent material thereof. For example, when the conductive layer is formed by sputtering, the thickness of the conductive layer is preferably 0.1 nm to 20 nm, and more preferably 1 nm to 10 nm. When the conductive layer is formed by printing techniques, the thickness of the conductive layer is preferably 0.1 μm to 50 μm, and more preferably 1 μm to 30 μm. 
     Sensor base  230  is formed of a material having an insulation property, e.g., resin such as polyethylene terephthalate, vinyl polymer, polyimide, polyester or styrenics; glass; or ceramics. The size of sensor base  230  is not limited to a specific numerical value. For example, the width of sensor base  230  is preferably 3 mm to 20 mm, and more preferably 5 mm to 10 mm. The length of sensor base  230  is preferably 20 mm to 40 mm. The thickness of sensor base  230  is preferably 0.1 mm to 1 mm. All of the width, length, and thickness of sensor base  230  are preferably within the above-described ranges. 
     Reagent  80  is disposed between sensor base  230  and spacer  220 . Reagent  80  may be disposed so as to contact at least a portion of working electrode  41  and counter electrode  42 . In addition reagent  80  may be disposed so as to also contact detection electrode  43 . The composition of reagent  80  is appropriately selected according to the type of a substrate to be measured. Generally, a reagent includes an enzyme, a mediator and the like. 
     Slit  225  is formed in spacer  220 . Slit  225  serves as a flow channel  240  for the injected biological sample. Flow channel  240  preferably communicates with, biological sample inlet  30 . Flow channel  240  is preferably a capillary flow channel, and it is preferable that the liquid biological sample have capillary action. This allows the biological sample landed on biological sample inlet  30  to smoothly flow into flow channel  240  to reach reagent  80 . 
     Air hole  215  is formed in cover  210 , and communicates with the end of slit  225 . Air hole  215  is preferably formed at a position away from biological sample inlet  30 , i.e., inner part of flow channel  240  when viewed from biological sample inlet  30 . When air hole  215  is provided in this way, it promotes a liquid biological sample to flow along the biological capillary flow channel. That is, air hole  215  plays a role of enhancing the capillary action (capillary phenomenon) so that the biological sample landed on biological sample inlet  30  smoothly flows into flow channel  240 . 
     A liquid biological sample is injected through biological sample inlet  30 , flows through flow channel  240  constituted by slit  225 , and reaches reagent  80 , where it dissolves reagent  80 . 
     Thereafter, a potential difference is created between working electrode  41  and counter electrode  42  (i.e., voltage is applied between working electrode  41  and counter electrode  42 ), and a current flowing in the sample solution into which reagent  80  is dissolved is measured. Based on the measured value, the presence or concentration of a substrate (measurement target) contained in the biological sample are determined. 
     [Regarding Differentiation of Type of Biological Sample Measurement Sensor] 
     If it is possible to employ a plurality of types of biological sample measurement sensors in a single biological sample measurement device, it is more convenient for users. To achieve this, it is required for the biological sample measurement device to be able to differentiate numerous types of biological sample measurement sensors. The biological sample measurement device of the present invention is characterized by having a light-emitting element and a light-receiving element and differentiating numerous types of biological sample measurement sensors by using the light-emitting element and the light-receiving element. 
     The biological sample measurement sensor of the present invention preferably has a colored section (see  FIG. 10  and Embodiment 1) or a light-transmissive section (see  FIG. 15  and Embodiment 2). A biological sample measurement device having a color sensor can determine the type of a sensor having a colored section (see  FIG. 7 ). A biological sample measurement device having a photodiode can determine the type of a biological sample measurement sensor having a light-transmissive section (see  FIG. 12 ). 
       FIGS. 10A to 10C  show examples of biological sample measurement sensor  200  having colored section  300 .  FIG. 10A  is a cross-sectional view of biological sample measurement sensor  200  (see  FIG. 4 ). Colored section  300  is preferably disposed on back surface  235  of sensor base  230 .  FIGS. 10B and 10C  show back surface  235  of sensor base  230 , specifically, the surface of sensor base  230  that is opposite to the surface where connection terminal section  40  is disposed. 
     As shown in  FIG. 10B , colored section  300  may be disposed, on the entire surface of back surface  235  of sensor base  230 ; however, colored section  300  may be disposed in an area to be irradiated with light emitted from the light-emitting element of the biological sample measurement device. For example, as shown in  FIG. 10C , colored section  300  may be disposed on the back surface of sensor base  230  in a region corresponding to connection terminal section  40  or a surrounding region thereof, when biological sample measurement sensor  200  is attached to sensor insertion port  7  of device main body  1  (see  FIG. 7 ). 
     Specifically, colored section  300  may be inserted into device main body  1  with biological sample measurement sensor  200  being attached to sensor insertion port  7  shown in  FIG. 7 . For example, about ⅔ of the entire biological sample measurement sensor  200  inserted from sensor insertion port  7  is accommodated inside device main body  1 . In this case, colored section  300  may cover, from the end of connection terminal section  40 , about ⅔ of the entire hack surface  235  of biological sample measurement sensor  200 . Needless to say, colored section  300  may cover smaller areas. 
     The biological sample measurement device of Embodiment 1 of the present invention has a light-emitting element and a light-receiving element. The light-emitting element applies light to the colored section, and the light-receiving element receives the light reflected from the colored section. By recognizing the color of the colored section, the light-receiving element can differentiate the type of a biological sample measurement sensor. 
       FIG. 15  shows an example of biological sample measurement sensor  200  having light-transmissive section  400 . Light-transmissive section  400  may be a through hole formed in connection terminal section  40  of biological sample measurement sensor  200 .  FIG. 15  shows 19 types ( 15 A to  15 S) of arrangement patterns of light-transmissive section  400 . In connection terminal section  40  of the sensor, a maximum of 9 through holes are formed (see  15 L). As shown in  15 N to  15 S of  FIG. 15 , the through hole may be a notched semicircle or other shape. 
     In addition,  15 P to  15 S of  FIG. 15  show examples in which light-transmissive section  400  is disposed at a position other than connection terminal section  40 . When light-transmissive section  400  is disposed, at a position other than connection terminal section  40 , the interference of connector terminal  17 , flexure section  17   a  or the like that comes in contact with connection terminal section  40  is reduced, and therefore light-emitting element  12 , light-receiving element  14 , and the like may be more freely arranged. In addition, biological sample measurement sensors  200  shown in  15 R and  15 S of  FIG. 15  include light-transmissive section  400  formed of notched semicircles, and light-transmissive section  400  formed of circular or tetragonal through holes. 
     Moreover, unlike other sensors, biological sample measurement sensor  200  shown in  15 S of  FIG. 15  has connection terminal section  40  having four electrodes (i.e., a working electrode, a counter electrode, a detection electrode, and a Hct electrode). 
     The number of light-transmissive section  400  (through hole) formed in biological sample measurement sensor  200  is not particularly limited, and is generally about 1 to 10. When the through hole is formed in connection terminal section  40  (cases shown in  FIGS. 15A to 15L ), the diameter of the through hole may be smaller than the width of the terminal section (conductive portion) corresponding to each electrode of connection terminal section  40 . In addition, when the through hole is formed at a position other than the portion of connection terminal section  40  (cases shown in  FIGS. 15M to 15S ), the foregoing restriction is not imposed. Generally, the diameter of the through hole is about 0.05 mm to 5 mm, and preferably about 0.1 mm to 2 mm. 
     Light-transmissive section  400  disposed in the biological sample measurement sensor may be disposed at a position other than connection terminal section  40 . 
     As described above, the shape of light-transmissive section  400  is not limited and can be circular, polygonal, semicircular, concave, wedged and/or the like. Moreover, light-transmissive section  400  is disposed in connection terminal section  40  and a surrounding region thereof; a central region of biological sample measurement sensor  200  other than connection terminal section  40  and a surrounding region thereof; lateral surface or end surfaces of biological sample measurement sensor  200 ; and so forth. The shape and arrangement of light-transmissive section  400  can be optionally selected and combined. In this way, the practicality of the biological sample measurement sensor of the present invention is enhanced. 
     The biological sample measurement device of Embodiment 2 of the present invention includes a light-emitting element and a light-receiving element. The light-emitting element applies light to the light-transmissive section formed of a through hole, and the light-receiving element receives the light passed through the light-transmissive section formed of a through hole. The light-receiving element recognizes the arrangement pattern of the through holes, whereby the type of biological, sample measurement sensor can be differentiated. 
     As a method of detecting the pattern of light-transmissive section  400 , an example of an optical detection method using light-emitting element  12  and light-receiving element  14  has been described above. However, the present invention is not limited to the optical detection method. For example, mechanical detection may be employed wherein a plurality of detection pins corresponding to respective holes of light-transmissive section  400  are provided. Alternatively, the presence of a semicircular and/or concave notch provided on the lateral surface/end surface of biological sample measurement sensor  200  can be mechanically detected, by means of detection pins from the lateral surface of the sensor. 
     In this manner, the biological sample measurement device of the present invention can differentiate the type of a biological sample measurement sensor by combining the light-emitting element with the light-receiving element; however, the biological sample measurement device can differentiate numerous types of biological sample measurement sensors by combining additional means with these elements. Examples of the additional include reading the pattern of the connection terminal section of the biological sample measurement sensor by using a connector terminal of the biological sample measurement device. This technique is disclosed in WO2003/076918. 
     As described above, biological sample measurement sensor  200  includes connection terminal section  40  (see  FIG. 5 ). By changing the pattern of the connection terminal section  40  according to the type of biological sample measurement sensor  200 , the biological sample measurement device can determine the type of biological sample measurement sensor  200 . 
       FIG. 6  shows three examples of pattern ( 6 A to  6 C) of connection terminal section  40  of biological sample measurement sensor  200 . The biological sample measurement device includes six connector terminals A to F which contact areas A to F, respectively. 
     According to the pattern shown in  FIG. 6A , among the six connector terminals A to F, A is conductive with B and D (indicated by “O” in the table). According to the pattern shown in  FIG. 6B , among the six connection terminal sections A to F, A is conductive with B and D, and E is conductive with F. According to the pattern shown in  FIG. 6C , among the six connector terminals A to F, A is conductive with B, C is conductive with D, and E is conductive with F. These results are summarized in the following table. 
     
       
         
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 Terminal-Terminal 
                   
               
             
          
           
               
                   
                 Type 
                 A-B 
                 A-D 
                 C-D 
                 E-F 
               
               
                   
                   
               
               
                   
                 a 
                 ◯ 
                 ◯ 
                 X 
                 X 
               
               
                   
                 b 
                 ◯ 
                 ◯ 
                 X 
                 ◯ 
               
               
                   
                 c 
                 ◯ 
                 X 
                 ◯ 
                 ◯ 
               
               
                   
                   
               
             
          
         
       
     
     Accordingly, the biological sample measurement device having six connector terminals A to F can differentiate the patterning shown in  FIGS. 6A to 6C . That is, when the value of electric resistance between, connector terminals of the biological sample measurement device is measured, three types of pattern can be differentiated. 
     In this manner, the patterns shown in  FIGS. 6A to 6C  can be differentiated based on whether or not connector terminals are conductive with each other. In addition, the connection terminal section of the biological sample measurement sensors may be patterned such that the value of electrical resistance varies among connector terminals. That is, when the value of electrical resistance is divided into three levels, it is possible to differentiate three different sensors by using two connector terminals. In this way, numerous types of sensors can be differentiated. 
     The number of connector terminals is not limited to 6. When the number of connector terminals is increased, it is possible to differentiate a larger number of sensor types. 
     As described above, in the biological sample measurement device of the present invention, a colored section (Embodiment 1) or a light-transmissive section (Embodiment 2) is disposed in the biological sample measurement sensor, whereby the type of the biological sample measurement sensor can be determined. Moreover, in the biological sample measurement device of the present invention, the connection terminal section of the biological sample measurement sensor is patterned, whereby the type of a larger number of biological sample measurement sensors can be determined. As a result, even when the type of sensors increases, the biological sample measurement device can differentiate each sensor from the other, and it is thus possible to perform appropriate measurement according to the type of sensor. 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     Embodiment 1 
       FIG. 7  shows the inside in the vicinity of connector  11  of biological sample measurement device  100  to which biological sample measurement sensor  200  has been attached (see  FIG. 1 ). Liquid crystal display element  9  and the like are not illustrated in the drawing. 
     As described above, biological sample measurement sensor  200  is composed of cover  210 , spacer  220 , and plate-like sensor base  230  (see  FIGS. 3 to 5 ). In addition, biological sample inlet  30  is disposed at one end (left side of  FIG. 7 ) of sensor base  230 , and connection terminal section  40  is disposed at the other end (right side of  FIG. 7 ) of sensor base  230  (see  FIG. 5 ). Connection terminal section  40  is attached to biological sample measurement device  100  so as to face flexure section  17   a  of connector terminal  17 . 
     In addition, as shown in  FIG. 10 , colored section  300  is disposed on back surface  235  of sensor base  230  of biological sample measurement sensor  200 . Colored section  300  may be colored with any color, e.g., white, blue or green. Colored section  300  may be disposed over the entire surface of back surface  235  or may be disposed only on a portion of back surface  235 . For example, colored section  300  may be disposed only on a portion that comes in contact with transparent cover  16  (see  FIG. 7 ). 
     Colored section  300  may also be disposed on a plurality of portions of back surface  235 , with each colored section  300  having a different color. When a plurality of colored sections  300  is disposed, it is preferable to dispose a plurality of light-receiving elements  14  (color sensors) corresponding to the respective colored sections  300 . 
     Different colors for colored section  300  can indicate different types of biological sample measurement sensor  200 , the details of which will be described later. For example, a biological sample measurement sensor having white-colored section  300  can be a sensor for measuring a blood glucose level for 5 seconds; a biological sample measurement sensor having a blue-colored section  300  can be a sensor for measuring a blood glucose level for 7 seconds; and a biological sample measurement sensor having green-colored section  300  can be a sensor for measuring a lactic acid level. 
     Light-emitting element  12  is composed of, for example, an LED. The light to be emitted from light-emitting element  12  may be white light or colored light. Light-receiving element  14  is a color sensor. The color sensor may be able to detect three colors of RGB or detect a single color (any one of RGB). Light shielding plate  15  is disposed between light-emitting element  12  and light-receiving element  14 . Light shielding plate  15  is, for example, a black non-reflective or low-reflective material. With light shielding plate  15 , the light emitted from light-emitting element  12  is prevented from leaking toward light-receiving element  14 . Therefore, the detection accuracy of light-receiving element  14  is improved, and as a result, the determination reliability of biological sample measurement sensor  200  is enhanced. 
     In addition, a transparent cover  16  that covers light-emitting element  12  and light-receiving element  14  is provided. The surface of transparent cover  16 , which faces light-emitting element  12  and light-receiving element  14 , contacts light shielding plate  15 . By providing transparent cover  16 , even if biological sample measurement sensor  200  is inserted into sensor insertion port  7  repeatedly, dust or the like is prevented from coming into contact with light-emitting element  12  and/or light-receiving element  14  (color sensor). Accordingly, the determination reliability of biological sample measurement sensor  200  is enhanced. 
     The surface of transparent cover  16  that faces away light-emitting element  12  and light-receiving element  14  is a contact surface that comes in contact with biological sample measurement sensor  200 . Moreover, there are provided connector terminals  17  on the side of transparent cover  16  that faces away light-emitting element  12  and light-receiving element  14 . Specifically, a plurality of connector terminals  17  is disposed at a predetermined interval. 
     Biological sample measurement sensor  200  is inserted into the measurement device through sensor insertion port  7  disposed in main body case  1 , and disposed in the gap formed between the contact surface of transparent cover  16  and connector terminal  17 . 
     Connector terminal  17  is disposed in connector  11 . Flexure section  17   a  as a portion of connector terminal  17  can be connected, to connection terminal section  40  (see  FIG. 10 ) of the attached biological sample measurement sensor  200 . Flexure section  17   a  of connector terminal  17  can press colored section  300  of biological sample measurement sensor  200  against the contact surface of transparent cover  16 . Consequently, light emitted from light-emitting element  12  can appropriately reach the colored section. Therefore, the determination reliability of biological sample measurement sensor  200  is enhanced. 
     Flexure section  17   a  is preferably disposed closer to sensor insertion port  7  than is light shielding plate  15 . In order to prevent biological sample measurement sensor  200  from being distorted near sensor insertion port  7  by receiving stress from flexure section  17   a , it is preferable to provide flexure section  17   a  of connector terminal  17  closer to sensor insertion port  7  than is light shielding plate  15 . If biological sample measurement sensor  200  is distorted near sensor insertion port  7 , external light enters through sensor insertion port  7 . In this way, by the position for disposing flexure section  17   a , the determination reliability of biological sample measurement sensor  200  can be heightened. 
     As shown in  FIG. 7 , connector  11  includes light-emitting element  12  and light-receiving element  14  which are disposed in the lower portion inside main body case  1 . Light-emitting element  12  emits light toward colored section  300  (see  FIG. 10 ) of biological sample measurement sensor  200  attached to connector  11 . The light passes through transparent cover  16  and is emitted to colored section  300  of biological sample measurement sensor  200 . The light applied to biological sample measurement sensor  200  is reflected, and the reflected light is received by light-receiving element  14  (color sensor). The color of the reflected light is affected by colored section  300  of biological sample measurement sensor  200 . 
       FIG. 8  is an electrical control block diagram of the biological sample measurement device shown in  FIG. 7 . Control section  18  composed of a microprocessor attached to control board  10  is connected to display section  4 , power switch  5 , scroll switch  6 , battery  8 , light-emitting element  12 , light-receiving element  14 , and connector terminal  17 . Control section  18  is also connected to memory  19 , buzzer  20 , and communication port  21 . 
     Connector terminal  17  is connected to measurement section  22 , and light-receiving element  14  is connected to light-receiving section  23 . Light-receiving section  23  and memory  19  are connected to correction section  24 , and correction section  24  is connected to determination section  25 . 
       FIG. 9  shows the flow of an operation for determining the color of biological sample measurement sensor  200  that is performed by the biological sample measurement device shown in  FIG. 7 . When power switch  5  (sec  FIG. 1 ) is turned on, the color determination operation is started (S 1 ). When the color determination operation is started, it is determined whether or not biological sample measurement sensor  200  has been inserted into sensor insertion port  7  and attached to connector  11  (S 2 ). 
     Specifically, attachment of biological sample measurement sensor  200  is determined by whether or not flexure section  17   a  of connector terminal  17  has been connected to connection terminal section  40  of biological sample measurement sensor  200 . When it is determined that the sensor has not been attached, the device is placed in a standby state (S 3 ). 
     When it is determined that the sensor has been attached, light-emitting element  12  (LED) emits light (S 4 ). Then the light (e.g., white light) emitted from light-emitting element  12  passes through transparent cover  16  and is obliquely applied to back surface  235  of sensor base  230  of biological sample measurement sensor  200  (see  FIG. 7 ). The emitted light is reflected from back surface  235  of sensor base  230 . Light-receiving element  14  receives the reflected light that passed through transparent cover  16  (S 5 ). Light-receiving element  14  as a color sensor transmits the color data of the light received via light-receiving section  23  to correction section  24  (S 6 ). 
     Meanwhile, correction section  24  reads correction data stored in memory  19  (S 7 ). Thereafter, based on the correction data thus read, correction section  24  corrects the color data received from light-receiving element  14  (color sensor) (S 8 ). The color sensor has a sensitivity spectrum (a certain range of sensitivity). Therefore, it is preferable to correct the color data to convert the data into preset standard color data. In this manner, the determination (described later) performed in S 9  has more accuracy. 
     The corrected color data is transmitted to determination section  25 , and determination section  25  determines the type of biological sample measurement sensor  200  (S 9 ). Specifically, the color of colored section  300  on back surface  235  of sensor base  230  of biological sample measurement sensor  200  is determined. 
     When the determination section fails to determine the color of colored section  300  in S 9 , the biological sample measurement sensor attached is determined to be an inappropriate sensor (S 11 ), and the measurement operation is automatically stopped (S 12 ). 
     As a result of the determination in S 9 , when the type of biological sample measurement sensor  200  can be determined, the process moves on an operation for measuring the biological sample (S 10 ), and measurement section  22  measures the substrate in the biological sample. For example, when the color is determined to be white in S 9 , a blood glucose level is measured in measurement section  22  for 5 seconds; when the color is determined to be blue, a blood glucose level is measured in measurement section  22  for 7 seconds; and when the color is determined to be green, a lactic acid level is measured in measurement section  22 . 
     As described above, Embodiment 1 enables to determine the type of biological sample measurement sensor  200  by the color of the sensor by means of light-emitting element  12  and light-receiving element  14  (color sensor). In addition, since users can easily recognize the color of colored section  300  of biological sample measurement sensor  200 , the user can also easily differentiate the type of biological sample measurement sensor  200  by him/herself. 
     Biological sample measurement sensor  200  used in Embodiment 1 can be obtained by simply providing a colored section to a biological sample measurement sensor in the related art. Consequently, the sensor can be easily produced at a low cost. 
     The type of biological sample measurement sensor  200  may be differentiated not only by using the colored section as in Embodiment 1, but also by reading the pattern such as that shown in  FIG. 6  of connection terminal section  40  of biological sample measurement sensor  200  by using connector terminal  17  of biological sample measurement device  100 . That is, when recognition of color of biological sample measurement sensor  200  described above is combined with the pattern of connection terminal section  40 , it is possible to differentiate more various types of biological sample measurement sensors. 
     Modified Example of Embodiment 1 
     In Embodiment 1, as shown in  FIG. 7 , colored section  300  is disposed on the back surface of biological sample measurement sensor  200  in a region corresponding to connection terminal section  40  (i.e., a surface that is opposite to the surface to which connector terminal  17  contacts) (see  FIG. 10 ), and when biological sample measurement sensor  200  is attached, colored section  300  is positioned inside connector  11 . Accordingly, light-emitting element  12  and light-receiving element  14  (color sensor) are disposed inside connector  11 . 
     In contrast, in this modified example, light-emitting element  12  and light-receiving element  14  (color sensor) are disposed outside connector  11 , as shown in  FIG. 11 . In this case, when biological sample measurement sensor  200  is attached, colored section  300  of biological sample measurement sensor  200  is positioned outside connector  11 . Except this point, this example is the same as the above example, and the same sections are marked with the same reference signs to skip the description thereof. 
     As shown in  FIG. 11 , light-emitting element  12  and light-receiving element  14  (color sensor) are disposed outside connector  11 . Accordingly, light-emitting element  12  and light-receiving element  14  less interfere with connector  11 , connector terminal  17 , flexure section  17   a , and the like. Therefore, the degree of freedom in arranging light-emitting element  12 , light-receiving element  14  and the like is more improved, compared to Embodiment 1. 
     As shown in  11 , when light-emitting element  12  and light-receiving element  14  (color sensor) are disposed outside connector  11 , a second light shielding plate  15   a  is further disposed at sensor insertion port  7  side, whereby external light through sensor insertion port  7  of device main body  1  can be blocked. By blocking the external light, the detection accuracy of light-receiving element  14  is improved, and the reliability in color determination is improved. 
     In addition, light-emitting element  12 , light-receiving element  14 , or the like may be disposed on sensor insertion port  7  side (see  FIG. 11 ) of connector  11  or besides connector  11  (inside of the paper in  FIG. 11 ). 
     Also in the modified example of Embodiment 1, as shown in  FIG. 6 , the pattern of connection terminal section  40  of biological, sample measurement sensor  200  is read by the connector terminal of the biological sample measurement device, whereby the type of the biological sample measurement sensor  200  can be differentiated. That is, by combining the recognition of the color of biological sample measurement sensor  200  in the modified example of the above Embodiment 1 with the pattern of the connection terminal section, it is possible to differentiate more various types of biological sample measurement sensors. 
     Embodiment 2 
     As with  FIG. 7 ,  FIG. 12  shows the inside in the vicinity of connector  11  of the biological sample measurement device to which biological sample measurement sensor  200  has been attached. The same members as shown in  FIG. 7  are marked with the same reference signs to omit the description thereof in some cases. 
     Biological sample measurement sensor  200  in Embodiment 2 is the same as biological sample measurement sensor  200  in Embodiment 1, except that the biological sample measurement sensor  200  of Embodiment 2 has light-transmissive section  400  (see  FIG. 15 ). As shown in  FIG. 15 , biological sample measurement sensor  200  has light-transmissive section  400  including a through hole formed in connection terminal section  40 . 
     Biological sample measurement sensor  200  is attached to the biological sample measurement device such that connection terminal, section  40  (see  FIG. 15 ) faces flexure section  17   a  of connector terminal  17 . Biological sample measurement sensor  200  is inserted into the measurement device through insertion port  7  disposed in main body case  1 . 
     As shown in  FIG. 12 , connector  11  includes light-emitting element  12  facing one surface of biological sample measurement sensor  200  attached, and light-receiving element  14  facing other surface of biological sample measurement sensor  200  attached. In addition, light-emitting element  12  and light-receiving element  14  are covered with light shielding section  33 . Particularly, it is preferable that light shielding section  33  be disposed such that light through insertion port  7  is blocked. Light shielding section  33  uses, for example, a non-reflective or low-reflective material of black color. 
     Connector  11  includes connector terminals  17 . Specifically, a plurality of connector terminals  17  is disposed at a predetermined interval. Flexure section  17   a , a portion, of connector terminal  17 , can be connected to connection terminal section  40  of biological sample measurement sensor  200  attached. 
     Light-emitting element  12  emits light toward the through hole as light-transmissive section  400  of biological sample measurement sensor  200  attached to connector  11 . The light passes through the through hole of biological, sample measurement sensor  200 , and the transmitted light is received by light-receiving element  14  (photodiode). Light-receiving element  14  is a photodiode which is attached to circuit board  10  and electrically connected to control section  18 . 
     It is preferable that one or more light-receiving elements  14  are disposed. The number of light-receiving elements  14  disposed is preferably the same as the maximum number of light-transmissive sections  400  that can be formed in biological sample measurement sensor  200 . For example, in order to differentiate all biological sample measurement sensors having the patterns  15 A to  15 L of  FIG. 15 , it is preferable that nine light-receiving elements  14  (photodiode) be formed in the biological sample measurement device. 
     Light-receiving element  14  recognizes the arrangement pattern of the through holes that serve as light-transmissive section  400 , whereby the type of biological sample measurement sensor  200  attached can be determined. 
     In addition, biological sample measurement sensor  200  of  15 P to  15 S of  FIG. 15  includes light-transmitting section  400  not in connection terminal section  40 , but in a region other than connection terminal section  40 . Accordingly, the light-receiving elements (photodiode) are disposed not in the vicinity of connection terminal section  40  of biological sample measurement sensor  200  attached, but at positions away from the connection terminal section  40 . Consequently, a problem hard to arise that the light to be received by the light-receiving element (photodiode) is interfered with by connector terminal  17  or flexure section  17   a.    
     Biological sample measurement sensor  200  of  15 N,  15 O, and  15 Q to  15 S of  FIG. 15  does not include light-transmissive section  400  formed of a through hole, but includes light-transmissive section  400  formed of a notch having a semicircular, concave, wedged or other shape disposed in the side surface or end surface of biological sample measurement sensor  200 . 
     When the pattern of light-transmissive section  400  of biological sample measurement sensor  200  has such a notch shape as described above, the pattern may be optically detected using light-emitting element  12  and light-receiving element  14 . In addition, the pattern can be mechanically detected using a method of recognizing the pattern of light-transmissive section  400  by bringing detection pins into contact with the biological sample measurement sensor  200  from the lateral surface, a method of using a micro switch, and the like. 
       FIG. 13  is an electrical control block diagram of the biological sample measurement device shown in  FIG. 12 . Control section  18  formed of a micro processor attached to control board  10  is connected to display section  4 , power switch  5 , scroll switch  6 , battery  8 , light-emitting element  12 , light-receiving element  14  (photodiode), and connector terminal  17 . Control section  18  is also connected to buzzer  20  and communication port  21 . 
     Connector terminal  17  is connected to measurement section  22 , and light-receiving element  14  is connected to light-receiving section  23 . Light-receiving section  23  is connected to determination section  25 . 
       FIG. 14  shows the flow of a determination operation for recognizing biological sample measurement sensor  200  by biological sample measurement device  100  (see  FIG. 1 ) shown in  FIG. 12 . When power switch  5  (see  FIG. 1 ) is turned on, the determination operation is started (S 1 ). When the determination operation is started, it is determined whether or not biological sample measurement sensor  200  has been inserted into sensor insertion port  7  and attached to the biological sample measurement device (S 2 ). 
     Specifically, attachment of biological sample measurement sensor  200  is determined by whether or not flexure section  17   a  of connector terminal  17  has been connected to the connection terminal section of biological sample measurement sensor  200 . When no connection is detected, the device is placed in a standby state (S 3 ). 
     When it is determined that biological sample measurement sensor  200  has been attached, light-emitting element  12  emits light (LED) (S 4 ). Light (e.g., white light) emitted from light-emitting element  12  passes through light-transmissive section  400  of biological sample measurement sensor  200  (see  FIG. 12 ). Light-receiving element  14  (photodiode) receives the transmitted light (S 5 ). When a plurality of light-receiving elements  14  is provided, not all light-receiving elements  14  necessarily receive the transmitted light. Depending on the arrangement of light-transmissive sections  400 , some of light-receiving elements  14  receive the transmitted light and some do not receive the transmitted light. 
     A signal from light-receiving element  14  that received light is input in light-receiving section  23  and transmitted to determination section  25  (see  FIG. 13 ). Determination section  25  detects the arrangement pattern (the number and arrangement of the light-transmissive sections) of the light-transmissive section (S 6 ). From the arrangement pattern detected, determination section  25  determines the type of biological sample measurement sensor  200  (S 9 ). 
     When determination section  25  fails to determine the type of biological sample measurement sensor  200  in S 9 , it is determined that the attached sensor is an inappropriate sensor. Accordingly, an error process is performed (S 11 ), and the measurement operation is automatically stopped (S 12 ). At this time, an error code or error message may be displayed on display section  4 , or warning sound may be played by buzzer  20 . 
     When the type of biological sample measurement sensor  200  can be determined as a result of the determination in S 9 , the process moves on the measurement operation of a biological sample (S 10 ), and measurement section  22  measures the substrate in the biological sample. 
     The accuracy in detecting the presence or absence of the transmitted light by a photodiode as in Embodiment 2 tends to be higher than the accuracy in detecting color information by the color sensor as in Embodiment 1. Accordingly, according to Embodiment 2, the type of a biological sample measurement sensor can be more accurately determined in some cases. 
     In addition, the type of biological sample measurement sensor  200  may be differentiated by the light-transmissive section of Embodiment 2. and at the same time by reading the pattern of connection terminal section  40  of biological sample measurement sensor  200  by means of the connector terminal of the biological sample measurement device as shown in  FIG. 6 . That is, by combining the recognition of biological sample measurement sensor  200  by using the above light-transmissive section with the pattern of the connection terminal section, it is possible to differentiate more various types of biological sample measurement sensors. 
     Modified Example of Embodiment 2 
     In Embodiment 2, light-transmissive section  400  is provided in biological sample measurement sensor  200  at the position of connection terminal section  40 , and light-transmissive section  400  is positioned inside connector  11  when biological sample measurement sensor  200  is attached, as shown in  FIG. 12 . Accordingly, light-emitting element  12  and light-receiving element  14  (photodiode) are disposed inside connector  11 . 
     In contrast, in the present embodiment, light-emitting element  12  and light-receiving element  14  (photodiode) are disposed outside connector  11 , as shown in  FIG. 16 . In this case, light-transmissive section  400  of biological sample measurement sensor  200  is positioned outside connector  11 , when biological sample measurement sensor  200  is attached. The present example is the same as the above example except for this point, and the same sections are marked with the same reference signs to skip the description thereof. 
     As shown in  FIG. 16 , since light-emitting element  12  and light-receiving element  14  (photodiode) are disposed outside connector  11 , light-emitting element  12  and light-receiving element  14  less interfere with connector  11 , connector terminal  17 , flexure section  17   a  and the like. Consequently, the degree of freedom in arranging light-emitting element  12 , light-receiving element  14 , and the like is more improved, compared to Embodiment 1. 
     Examples of the pattern of light-transmissive section  400  of biological sample measurement sensor  200  used in the present modified example are shown in  15 P to  15 S of  FIG. 15 . In biological sample measurement sensor  200  of  FIG. 15P , light-transmissive section  400  formed of a plurality of circular through holes is disposed in a region other than connection terminal section  40 . In this case, it is advantageous to provide a plurality of light-receiving elements  14 . In biological sample measurement sensor  200  of  15 Q of  FIG. 15 , light-transmissive section  400  formed of notches is provided in the lateral, surface of biological sample measurement sensor  200  in a region other than connection terminal section  40 . 
     Biological sample measurement sensor  200  of  15 R shown in  FIG. 15  shows an example in which light-transmissive section  400  formed of a through hole shown in  15 P shown  FIG. 15  is combined with light-transmissive section  400  formed of notches shown in  15 Q shown in  FIG. 15 . Similarly to the biological sample measurement sensor of  15 R shown in  FIG. 15 , the biological sample measurement sensor of  15 S shown in FIG.  15  includes light-transmissive section  400  formed of a through hole and light-transmissive section  400  formed of notches. This sensor shows a case where the shape of the hole of light-transmissive section  400  formed of a through hole is a polygon such as tetragon, and connection terminal section  40  has four electrodes. The four electrodes include a working electrode, a counter electrode, a detection electrode, and a Hct electrode. 
     In addition, as shown in  FIG. 16 , a second light shielding section  33   a  for blocking external light may be disposed at sensor insertion port  7  side of device main body  1 . When the external light is blocked, the accuracy in detecting the pattern of light-transmissive section  400  by means of light-receiving element  14  is improved, and determination reliability is improved. 
     Also in the modified example of Embodiment 2, the pattern of connection terminal section  40  of biological sample measurement sensor  200  is read by the connector terminal of the biological sample measurement device as shown in  FIG. 6 , whereby the type of biological sample measurement sensor  200  can be differentiated. That is, by combining the recognition of biological sample measurement sensor  200  by means of light-transmissive section  400  in the above modified example of Embodiment 2 with the pattern of the connection terminal section, it is possible to differentiate more various types of biological sample measurement sensors. 
     The color-based sensor recognition system described in Embodiment 1 and the sensor recognition system using light-transmissive section  400  demonstrated in Embodiment 2 have been described above. The systems may be used independently or in combination. Moreover, in addition to the combination, when the pattern of connection terminal section  40  is read by connector terminal  17  of biological sample measurement device  100 , it is also possible to differentiate the type of biological sample measurement sensor  200 . 
     INDUSTRIAL APPLICABILITY 
     Unlike the conventional measurement devices that use a barcode reader, the biological, sample measurement device of the present invention can determine the type of a large number of biological sample measurement sensors, without requiring means for scanning light or means for reading the scanned light. Therefore, the device of the present invention can relatively, easily, and sufficiently respond to the increase in the type of biological sample measurement sensors that will be caused by the increase in the application or the type of devices that may be required in the future. Accordingly, it is possible to reduce the cost of the biological sample measuring device. Consequently, for example, utilization of the biological sample measurement device is expected. 
     REFERENCE SIGNS LIST 
     
         
           1  Main body case 
           2  Top cover 
           3  Bottom cover 
           4  Display section 
           5  Power switch 
           6  Scroll switch. 
           7  Sensor insertion port 
           8  Battery 
           9  Liquid crystal display element 
           10  Control board 
           11  Connector 
           12  Light-emitting element 
           14  Light-receiving element 
           15  Light shielding plate 
           16  Transparent cover 
           17  Connector terminal 
           17   a  Flexure section 
           18  Control section 
           19  Memory 
           20  Buzzer 
           21  Communication port 
           22  Measurement section 
           23  Light-receiving section 
           24  Correction section 
           25  Determination section 
           30  Biological sample inlet 
           31  Sensor determination section 
           33  Light shielding section 
           40  Connection terminal section 
           80  Reagent 
           100  Biological sample measurement device 
           200  Biological sample measurement sensor 
           210  Cover 
           215  Air hole 
           220  Spacer 
           225  Slit 
           230  Sensor base 
           235  Back surface of sensor base 
           240  Flow channel 
           300  Colored section 
           400  Light-transmissive section
The purpose of the present invention is to reduce costs for biological sample measurement devices by means of providing a novel method for easily and reliably identifying types of biological sample measurement sensors. Specifically, the present invention provides a biological sample measurement device provided with a main body case, a sensor insertion port, a connector, a light-emitting element and a light-receiving element disposed inside of the main body case in the vicinity of the connector, and a connector terminal. The light-emitting element can irradiate light onto a biological sample measurement sensor attached to the connector. The light-receiving element can receive reflected light or transmitted light from the biological sample measurement sensor attached to the connector. The type of the biological sample measurement sensor is identified on the basis of the light received and recognized by the light-receiving element.