BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a sensor attachable to the body and a monitoring apparatus including the sensor. 
         [0003]    2. Description of the Related Art 
         [0004]    Recently, there has been proposed a monitoring apparatus configured in an adhesive plaster type or a para-aminosalicylic acid (PAS) type and to be attachable to the body, thereby enabling a patient to live without inconvenience in the state in which the patient wears the monitoring apparatus. 
         [0005]    In this monitoring apparatus which is attachable to the body, a sensor can have a variety of sizes. 
         [0006]    In general, if a sensor is an adhesive plaster type, the sensor is formed to have a size of 3 cm by 7 cm. If the sensor is a PAS type, the sensor is formed to have a size of 10 cm by 10 cm. In case where the monitoring apparatus is attached to the body, it is not desirable to blindly increase its area because of considering convenience of the user. In order to configure the sensor circuit within this limited area, it should be made by high-density structures. However, such the high-density circuit will increase the production cost of the apparatus. 
       SUMMARY OF THE INVENTION 
       [0007]    An object of an embodiment is to provide a sensor and a monitoring apparatus using such the sensor which are attachable to the body, wherein the sensor has a maximized area efficiency and give a wearable convenience to the user in the state in which the patient wears the monitoring apparatus. 
         [0008]    A sensor according to an embodiment is an attachable sensor for measuring bio signals, including a sensor layer formed to be attachable to the skin and configured to have a plurality of sensor layers configured to measure different types of bio signals stacked thereon, a power source configured to supply power to the sensor layer, and sensing electrodes configured to sense the bio signals from the human body, wherein the plurality of sensor layers receives the respective signals sensed by the sensing electrodes and determines whether the received signals can be measured, and a corresponding sensor layer capable of measuring the sensed signal is activated. 
         [0009]    The sensor preferably includes a flexible board, a circuit pattern installed on the flexible board, a plurality of passive elements connected to the circuit pattern, and a sensor chip connected to the circuit pattern and configured to measure the bio signals. 
         [0010]    The flexible board preferably includes one of paper of pulp material, non-woven fabric, textiles, a patch of knitting, and a film. 
         [0011]    The circuit pattern preferably is formed by forming a conductive paste on the flexible board in a circuit form using one of a silk screen method, a vacuum deposition method, and a sputtering deposition method or formed by cutting metal in a pattern of a circuit form and attaching the cut metal on the flexible board, and the sensor chip is bonded to the circuit pattern through flip-chip bonding, wire bonding, or tab bonding. 
         [0012]    A sensor according to an embodiment is an attachable sensor for measuring bio signals, including a sensor layer configured to include a flexible board, a circuit pattern installed on the flexible board, a plurality of passive elements connected to the circuit pattern, and a sensor chip connected to the circuit pattern and configured to measure the bio signals, a power source configured to supply power to the sensor layer, and a sensing electrode configured to sense the bio signals from the human body, wherein a sensor circuit formed of the flexible board and the circuit pattern is plural, and the plurality of sensor circuits is coupled in a stack form. 
         [0013]    The flexible board preferably includes one of paper of pulp material, non-woven fabric, textiles, a patch of knitting, and a film. 
         [0014]    The circuit pattern preferably is formed by forming a conductive paste on the flexible board in a circuit form using one of a silk screen method, a vacuum deposition method, and a sputtering deposition method or formed by cutting metal in a pattern of a circuit form and attaching the cut metal on the flexible board, and the sensor chip is bonded to the circuit pattern through flip-chip bonding, wire bonding, or tab bonding. 
         [0015]    A sensor according to an embodiment is an attachable sensor for measuring bio signals, including a sensor layer configured to include a flexible board, a circuit pattern installed on the flexible board, a plurality of passive elements connected to the circuit pattern, and a sensor chip connected to the circuit pattern and configured to measure the bio signals, a power source configured to supply power to the sensor layer, and a sensing electrode configured to sense the bio signals from the human body, wherein a sensor circuit formed of the flexible board and the circuit pattern is plural, and the plurality of sensor circuits is coupled in a stack form, a plurality of the sensor layers is configured so that the sensor layers measure different types of bio signals, respectively, and the plurality of sensor layers is stacked, and the plurality of sensor layers receives the respective signals sensed by the sensing electrodes and determines whether the received signals can be measured, and a corresponding sensor layer capable of measuring the sensed signal is activated. 
         [0016]    The flexible board preferably includes one of paper of pulp material, non-woven fabric, textiles, a patch of knitting, and a film. 
         [0017]    The circuit pattern preferably is formed by forming a conductive paste on the flexible board in a circuit form using one of a silk screen method, a vacuum deposition method, and a sputtering deposition method or formed by cutting metal in a pattern of a circuit form and attaching the cut metal on the flexible board, and the sensor chip preferably is bonded to the circuit pattern through flip-chip bonding, wire bonding, or tab bonding. 
         [0018]    A monitoring apparatus according to an embodiment is a monitoring apparatus for monitoring bio signals, including a sensor of an adhesive plaster type formed to be attachable to the skin and configured to include a sensor layer configured to have a plurality of sensor layers for measuring different types of bio signals, respectively, stacked thereon, a power source configured to supply power to the sensor layer, and sensing electrodes configured to sense the bio signals from the human body, and an external terminal configured to receive measured data through the sensor and process the received data, wherein the plurality of sensor layers receives the respective signals sensed by the sensing electrodes and determines whether the received signals can be measured, and a corresponding sensor layer capable of measuring the sensed signal is activated. 
         [0019]    The sensor preferably includes a flexible board, a circuit pattern installed on the flexible board, a plurality of passive elements connected to the circuit pattern, and a sensor chip connected to the circuit pattern and configured to measure the bio signals. 
         [0020]    The flexible board preferably includes one of paper of pulp material, non-woven fabric, textiles, a patch of knitting, and a film. 
         [0021]    The circuit pattern preferably is formed by forming a conductive paste on the flexible board in a circuit form using one of a silk screen method, a vacuum deposition method, and a sputtering deposition method or formed by cutting metal in a pattern of a circuit form and attaching the cut metal on the flexible board, and the sensor chip preferably is bonded to the circuit pattern through flip-chip bonding, wire bonding, or tab bonding. 
         [0022]    The sensor chip preferably transmits the measured data to the external terminal wirelessly. 
         [0023]    The monitoring apparatus preferably further includes an inductor connected to the sensor chip, wherein the inductor is connected to the external terminal using inductive coupling or radio frequency (RF) communication. 
         [0024]    A monitoring apparatus according to an embodiment is a monitoring apparatus for monitoring bio signals, including a sensor of an adhesive plaster type configured to include a sensor layer comprising a flexible board, a circuit pattern installed on the flexible board, a plurality of passive elements connected to the circuit pattern, and a sensor chip connected to the circuit pattern and configured to measure the bio signals, a power source configured to supply power to the sensor layer, and a sensing electrode configured to sense the bio signals from the human body, and an external terminal configured to receive measured data through the sensor and process the received data, wherein a sensor circuit formed of the flexible board and the circuit pattern is plural, and the plurality of sensor circuits is coupled in a stack form. 
         [0025]    The flexible board preferably includes one of paper of pulp material, non-woven fabric, textiles, a patch of knitting, and a film. 
         [0026]    The circuit pattern preferably is formed by forming a conductive paste on the flexible board in a circuit form using one of a silk screen method, a vacuum deposition method, and a sputtering deposition method or formed by cutting metal in a pattern of a circuit form and attaching the cut metal on the flexible board, and the sensor chip preferably is bonded to the circuit pattern through flip-chip bonding, wire bonding, or tab bonding. 
         [0027]    The sensor chip preferably transmits the measured data to the external terminal wirelessly. 
         [0028]    The monitoring apparatus preferably further includes an inductor connected to the sensor chip, wherein the inductor is connected to the external terminal using inductive coupling or radio frequency (RF) communication. 
         [0029]    A monitoring apparatus according to an embodiment is a monitoring apparatus for monitoring bio signals, including a sensor of an adhesive plaster type configured to include a sensor layer comprising a flexible board, a circuit pattern installed on the flexible board, a plurality of passive elements connected to the circuit pattern, and a sensor chip connected to the circuit pattern and configured to measure the bio signals, a power source configured to supply power to the sensor layer, and a sensing electrode configured to sense the bio signals from the human body, and an external terminal configured to receive measured data through the sensor and process the received data, wherein a sensor circuit formed of the flexible board and the circuit pattern is plural, and the plurality of sensor circuits is coupled in a stack form, a plurality of the sensor layers is configured so that the sensor layers measure different types of bio signals, respectively, and the plurality of sensor layers is stacked, and the plurality of sensor layers receives the respective signals sensed by the sensing electrodes and determines whether the received signals can be measured, and a corresponding sensor layer capable of measuring the sensed signal is activated. The flexible board preferably includes one of paper of pulp material, non-woven fabric, textiles, a patch of knitting, and a film. 
         [0030]    The circuit pattern preferably is formed by forming a conductive paste on the flexible board in a circuit form using one of a silk screen method, a vacuum deposition method, and a sputtering deposition method or formed by cutting metal in a pattern of a circuit form and attaching the cut metal on the flexible board, and the sensor chip preferably is bonded to the circuit pattern through flip-chip bonding, wire bonding, or tab bonding. 
         [0031]    The sensor chip preferably transmits the measured data to the external terminal wirelessly. 
         [0032]    The monitoring apparatus preferably further includes an inductor connected to the sensor chip, wherein the inductor is connected to the external terminal using inductive coupling or radio frequency (RF) communication. 
         [0033]    According to the present invention, there is provided a wearable sensor and a monitoring with a maximized area efficiency. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]      FIG. 1A  is a diagram showing an example of the construction of a monitoring apparatus in accordance with a first embodiment; 
           [0035]      FIG. 1B  is a diagram showing an example of the construction of a sensor layer in accordance with an embodiment; 
           [0036]      FIG. 1C  is a diagram showing the construction of the bottom of a sensor in accordance with an embodiment; and 
           [0037]      FIG. 2  is a diagram showing an example of the construction of a monitoring apparatus in accordance with a second embodiment. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0038]    Reference will now be made in greater detail to a preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings and the description to refer to the same or like parts. 
       First Embodiment 
       [0039]      FIG. 1A  is a diagram showing an example of the construction of a monitoring apparatus  10  in accordance with a first embodiment.  FIG. 1B  is a diagram showing an example of the construction of a first sensor layer  110   a  in accordance with an embodiment.  FIG. 1C  is a diagram showing the construction of the bottom of a sensor  100  in accordance with an embodiment. 
         [0040]    Referring to  FIGS. 1A to 1C , the monitoring apparatus  10  in accordance with the first embodiment includes a sensor  100  and an external terminal  150 . 
         [0041]    Construction of the Sensor  100   
         [0042]    The sensor  100  includes a plurality of sensor layers  110   a  and  110   b , a power source  120 , and sensing electrodes  130   a  and  130   b.    
         [0043]    Each of the sensor layers  110   a  and  110   b  can be fabricated in an adhesive plaster type which can be attached to the skin. A plurality of the sensor layers  110   a  and  110   b  can be stacked. The plurality of sensor layers  110   a  and  110   b  can be configured to measure different types of bio signals, respectively. In the first embodiment, an example in which two sensor layers  110   a  and  110   b  (hereinafter referred to as a first sensor layer  110   a  and a second sensor layer  110   b ) are configured is described. 
         [0044]    The first sensor layer  110   a  includes a flexible board  111   a , a circuit pattern  113   a , a plurality of passive elements  115   a , and a sensor chip  117   a.    
         [0045]    The flexible board  111   a  can be configured to include one of paper of pulp material, non-woven fabric, textiles, a patch of knitting, and a film. Here, one of both faces of the flexible board  111   a  can be an adhesive surface having an adhesive property. 
         [0046]    The circuit pattern  113   a  can be formed by forming a conductive paste on the flexible board  111   a  in a circuit form using one of a silk screen method, a vacuum deposition method, and a sputtering deposition method. Or, the circuit pattern  113   a  can be formed by cutting metal in a pattern of a circuit form and attaching the cut metal on the flexible board  111   a . The circuit pattern  113   a  is formed on an opposite side to the adhesive surface of the flexible board  111   a.    
         [0047]    The passive elements  115   a  are installed on the circuit pattern  113   a  and can be electrically connected to the circuit pattern  113   a.    
         [0048]    The sensor chip  117   a  is installed on the circuit pattern  113   a  and can be electrically connected to the circuit pattern  113   a . The sensor chip  117   a  can be connected to the circuit pattern  113   a  by flip-chip bonding, wire bonding, or tab bonding. The sensor chip  117   a  can be a bare die IC chip. 
         [0049]    The sensor chip  117   a  can measure bio signals from the human body using the sensing electrodes  130   a  and  130   b . The sensor chip  117   a  can amplify the measured bio signals, perform filtering processing on the amplified signals, and convert them into digital data. Furthermore, the sensor chip  117   a  can perform processing processes, such as compression/encryption, on the converted data, store the processed data, and transmit the stored data to the external terminal  150  wirelessly. Or, the sensor chip  117   a  can wirelessly transmit the measured raw data to the external terminal  150  without change. 
         [0050]    Meanwhile, in case where the sensor chip  117   a  cannot be connected to the external terminal  150 , an inductor  140  (used as a RF antenna) can be additionally configured in the sensor layers  110   a  and  110   b . The inductor  140  can be installed at the top of the sensor layers  110   a  and  110   b , and it enables the sensor chip  117   a  and the external terminal  150  to be wirelessly coupled using inductive coupling circuit or Radio Frequency (RF) communication, functioning as a wireless module. Accordingly, the sensor chip  117   a  can transmit the measured data to the external terminal  150  through the inductor  140 . 
         [0051]    The sensor chip  117   a  can be configured to directly transmit the measured data wirelessly or can be configured to access the external terminal  150  through the inductor  140 , but the present invention is not necessarily limited to the above constructions. The sensor chip  117   a  can be configured to transmit the data, stored in the sensor chip  117   a , to the external terminal  150  through a wired method. 
         [0052]    The second sensor layer  110   b  includes a flexible board  111   b , a circuit pattern  113   b , a plurality of passive elements  115   b , and a sensor chip  117   b . The second sensor layer  110   b  has a similar construction as the first sensor layer  110   a . Here, the sensor chip  117   a  configured in the first sensor layer  110   a  and the sensor chip  117   b  configured in the second sensor layer  110   b  can be configured to measure different bio signals. 
         [0053]    The first sensor layer  110   a  and/or the second sensor layer  110   b  can include one or more sensor circuits. Here, the sensor circuits mean circuits formed of the flexible boards  111   a  and  111   b  and the circuit patterns  113   a  and  113   b . For example, if one sensor circuit is further configured in the first sensor layer  110   a , the sensor circuit can be stacked under a sensor circuit that is basically configured in the first sensor layer  110   a . Here, the added sensor circuit can be connected to the sensor circuit that is basically configured in the first sensor layer  110   a , and the two stacked sensor circuits can operate as one sensor circuit. The two stacked sensor circuits do not need to necessarily come in contact with each other physically and another element layer can be stacked in a middle layer between the two stacked sensor layers. However, the two sensor circuits need to be electrically coupled. The construction of the sensor circuits stacked as described above can increase area efficiency because the limited space (or area) of the sensor is utilized to a maximum extent. 
         [0054]    The power source  120  can be installed between the first sensor layer  110   a  and the second sensor layer  110   b , between the sensor circuit and the sensor circuit, or at the top of the sensor layers  110   a  and  110   b . The power source  120  can be connected to the sensor chips  117   a  and  117   b , and it can supply power to the sensor layers  110   a  and  110   b . The power source  120  can use a flexible battery or work based on wireless power transmission such as RFID. 
         [0055]      FIG. 1C  is a diagram showing the construction of the bottom of the sensor in accordance with an embodiment. 
         [0056]    The sensing electrodes  130   a  and  130   b  are configured to sense bio signals from the human body and connected to the respective sensor chips  117   a  and  117   b.    
         [0057]    The sensing electrodes  130   a  and  130   b  can be installed between the first sensor layer  110   a  and the second sensor layer  110   b  or at the bottom of the sensor layers  110   a  and  110   b . Here, the bottom of the sensor layers  110   a  and  110   b  can be the bottom of the flexible board  111   b  that is configured in the second sensor layer  110   b.    
         [0058]    The sensing electrodes  130   a  and  130   b  preferably are installed at the bottom of the sensor layers  110   a  and  110   b  in order to reduce a feeling of foreign material for the sensor  100 . The second sensor layer  110   b  can be disposed at the bottom of the sensor layer. In this case, the sensing electrodes  130   a  and  130   b  can be installed on the adhesive surface A of the flexible board  111   b  that is configured in the second sensor layer  110   b.    
         [0059]    Construction of the External Terminal  150   
         [0060]    The external terminal  150  can receive measured data through the sensor  100  and process the measured data. The external terminal  150  can perform processing processes, such as decompression/decoding, on the received data, and store the processed data. 
         [0061]    The external terminal  150  can be a portable terminal the user is having so that the external terminal  150  remotely transmits information through a wire or wireless network and receives signals to control the sensor  100 . 
         [0062]    Furthermore, if the inductor  140  for performing communication using inductive coupling or RF communication is configured in the sensor  100 , the external terminal  150  can be configured to perform communication with the sensor  100  using inductive coupling or RF communication. 
         [0063]    Meanwhile, the data communication between the external terminal  150  and the sensor  100  can be performed by a wired manner or by a human body communication technology. 
         [0064]    Construction of the Monitoring Apparatus  100   
         [0065]    First, when the sensor  100  is powered on, the sensor chips  117   a  and  117   b  can be initialized and connected to the power source  120 . 
         [0066]    Next, bio signals from the human body are sensed through the sensing electrodes  130   a  and  130   b , and then the sensed bio signals are inputted to the sensor chips  117   a  and  117   b . Each of the sensor chips  117   a  and  117   b  measures the received bio signal and determines whether the measured bio signal can be processed. Furthermore, each of the sensor chips  117   a  and  117   b  is activated or deactivated according to a result of the determination. 
         [0067]    For example, if it is determined that the bio signals sensed by the sensing electrodes  130   a  and  130   b  are bio signals that can be measured by the first sensor layer  110   a , the first sensor layer  110   a  can be activated, whereas the second sensor layer  110   b  can be deactivated. Accordingly, the first sensor layer  110   a  measures the bio signals from the human body using the sensing electrodes  130   a  and  130   b.    
         [0068]    In contrast, if it is determined that the bio signals sensed by the sensing electrodes  130   a  and  130   b  are bio signals that can be measured by the second sensor layer  110   b , the second sensor layer  110   b  can be activated, whereas the first sensor layer  110   a  can be deactivated. Accordingly, the second sensor layer  110   b  measures the bio signals from the human body using the sensing electrodes  130   a  and  130   b.    
         [0069]    Furthermore, a sensor layer to be activated can be selected in response to an external command, and when the selected sensor layer is activated, the sensor  100  may operate. 
         [0070]    Next, measured bio signals can be amplified and filtered through corresponding sensor chips and then converted into digital data. Furthermore, the converted data can be subject to processing processes, such as compression/encryption, through the corresponding sensor chips, and then stored, and the stored data can be transmitted to the external terminal  150 . Or, the measured raw data can be transmitted to the external terminal  150  without change. 
         [0071]    Meanwhile, if the inductor  140  is configured in the sensor  100 , data stored in a corresponding sensor chip can be transmitted to the external terminal  150  through the inductor  140 . 
       Second Embodiment 
       [0072]      FIG. 2  is a diagram showing an example of the construction of a monitoring apparatus  20  in accordance with a second embodiment. 
         [0073]    Referring to  FIG. 2 , the monitoring apparatus  20  in accordance with the second embodiment includes a sensor  200  and an external terminal  250 . Being different the first embodiment, the second embodiment can reduce a surface area of the sensor, by providing the sensor  200  having a plurality of layers  210   a  and  210   b.    
         [0074]    Construction of the Sensor  200   
         [0075]    The sensor  200  includes first and second sensor layers  210   a  and  210   b , a power source  220 , and sensing electrodes  230   a  and  230   b.    
         [0076]    The first sensor layer  210   a  can be fabricated in an adhesive plaster type which can be attached to the skin. 
         [0077]    The first sensor layer  210   a  includes a plurality of passive elements  215 , a sensor chip  217 , a circuit pattern  213   a , and a flexible board  211   a . The second sensor layer  210   a  includes a flexible board  211   b  and a circuit pattern  213   b . In  FIG. 2 , the second sensor layer  210   b  which does not include the sensor chip  217  can be configured by one array or a plurality of arrays. 
         [0078]    The first and second sensor layers  210   a  and  210   b  can be stacked and electrically coupled. Here, the plurality of sensor layers can operate as one sensing circuit. The stacked construction as described above can increase area efficiency because the limited space (or area) of the sensor is utilized to a maximum extent. 
         [0079]    The flexible boards  211   a  and  211   b  can be configured using paper of pulp material, non-woven fabric, textiles, a patch of knitting, and a film. Here, any one of both faces of the flexible boards  211   a  and  211   b  can be an adhesive surface having an adhesive property in order to be attached to human body for the sensor  200  or between sensor layers. 
         [0080]    The circuit patterns  213   a  and  213   b  can be formed by forming a conductive paste on the respective flexible boards  211   a  and  211   b  in a circuit form using one of a silk screen method, a vacuum deposition method, and a sputtering deposition method. Or, the circuit patterns  213   a  and  213   b  can be formed by cutting metal in a pattern of a circuit form and attaching them to the flexible boards  211   a  and  211   b , respectively. 
         [0081]    Preferably, the circuit patterns  213   a  and  213   b  are formed on an opposite side to the adhesive surface of the flexible boards  211   a  and  211   b.    
         [0082]    The passive elements  215  are installed on the circuit pattern  213   a  and can be electrically connected to the circuit pattern  213   a.    
         [0083]    The sensor chip  217  is installed on the circuit pattern  213   a  and can be electrically connected to the circuit pattern  213   a . The sensor chip  217  can be connected to the circuit pattern  213   a  through flip-chip bonding, wire bonding, or tab bonding. The sensor chip  217  can be a bare die IC chip. 
         [0084]    The sensor chip  217  can measure bio signals from the human body using the sensing electrodes  230   a  and  230   b . The sensor chip  217  can amplify and filter the measured bio signals and convert the processed data into digital data. Furthermore, the sensor chip  217  can perform processing processes, such as compression/encryption, on the converted data, store the processed data, and wirelessly transmit the stored data to the external terminal  250 . Or, the sensor chip  217  can transmit the measured raw data to the external terminal  250  wirelessly without change. 
         [0085]    Meanwhile, in case where the sensor chip  217  is configured so that it cannot be connected to the external terminal  250  in a wired manner, an inductor  240  can be additionally configured in the sensor layer  210 . The inductor  240  can be installed at the top of the sensor layer  210 , and it enables the sensor chip  217  and the external terminal  250  to be wirelessly coupled using inductive coupling or Radio Frequency (RF) communication. Accordingly, the sensor chip  217  can transmit information to the external terminal  250  through the inductor  240 . 
         [0086]    The sensor chip  217  can be configured to directly transmit the measured data wirelessly or can be configured to access the external terminal  250  through the inductor  240 , but the present invention is not necessarily limited to the above constructions. The sensor chip  217  can be configured to transmit the data, stored in the sensor chip  217 , to the external terminal  250  through a wired method. 
         [0087]    In accordance with the second embodiment, the sensor layer  210   a  or  210   b  can be configured by one or more arrays. In this case, the one or more sensor layers  210  can be configured like the sensor layers  110   a  and  110   b  of the first embodiment, and the sensor  200  has the similar operating method as the sensor  100  of the first embodiment. 
         [0088]    Furthermore, in case where it is necessary to integrate the circuits, each sensor layer can be configured to have a plurality of stacked structures. 
         [0089]    The power source  220  can be installed between the stacked sensor circuits  214   a  and  214   b  or at the top of the sensor layer  210 . The power source  220  can be connected to the sensor chip  217 , and it can supply power to the sensor chip  217 . The power source  220  can be a flexible battery. 
         [0090]    The sensing electrodes  230   a  and  230   b  are configured to sense bio signals from the human body and are connected to the sensor chip  217 . 
         [0091]    The sensing electrodes  230   a  and  230   b  can be installed in the stacked sensor circuits  214   a  and  214   b  or at the bottom of the sensor circuits  214   a  and  214   b . Here, the bottom of the sensor circuits  214   a  and  214   b  can be the bottom of the flexible board  211   b  that is configured at the lowest layer. 
         [0092]    The sensing electrodes  230   a  and  230   b  preferably are installed at the bottom of the sensor layers  210   a  and  210   b  in order to reduce a feeling of foreign material for the sensor  200 . In this case, the sensing electrodes  230   a  and  230   b  can be installed on the adhesive surface A of the flexible board  211   b  that is configured at the lowest layer. 
         [0093]    Construction of the External Terminal  250   
         [0094]    The external terminal  250  can receive measured data from the sensor  200  and process the received data. The external terminal  250  can perform processing processes, such as decompression/decoding, on the received data and store the processed data. 
         [0095]    Furthermore, if the inductor  240  for performing communication using inductive coupling or RF communication is configured in the sensor  200 , the external terminal  150  can be configured to communicate with the sensor  200  using inductive coupling or RF communication. 
         [0096]    Furthermore, the external terminal  250  can be connected to the sensor  200  in a wired manner and configured to communication with the sensor  200 . 
         [0097]    In accordance with an embodiment, if one or more bio signals are measured or a space that forms circuits needs to be extended, sensors are configured by piling up the sensors in a multi-layer structure. Accordingly, the degree of integration of circuits can be increased because a limited area can be utilized to a maximum extent. 
         [0098]    In accordance with an embodiment, the attachable sensor having maximized area efficiency and the monitoring apparatus including the sensor can be provided. 
         [0099]    Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and the spirit of the invention as disclosed in the accompanying claims. 
         [0100]    The present invention is used in a sensor attachable to the body and a monitoring apparatus including the sensor.
One embodiment of the present invention relates to a sensor for measuring biosignals. The sensor according to said embodiment comprises: a sensor layer formed by stacking a plurality of sensor layers that are attachable to the skin to measure different types of bio signals; a power for supplying power to the sensor layer; and a sensing electrode for sensing biosignals from the human body. The plurality of sensor layers takes the signals sensed by the sensing electrode as an input, and determines whether or not to measure the inputted signals. Then, the relevant sensor layer that can measure the sensed signal is activated.