Patent Publication Number: US-11662261-B2

Title: Sensor chip and force sensor device with increased fracture resistance

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2020-215554, filed Dec. 24, 2020, the contents of which are incorporated herein by reference in their entirety. 
     BACKGROUND 
     1. Field of the Invention 
     The present disclosure relates to a sensor chip and a force sensor device. 
     2. Description of the Related Art 
     Force sensor devices for detecting displacements in one or more predetermined axial directions have been known. As an example of such a force sensor device, a force sensor device includes a structure including (i) a sensor chip, (ii) an external force receiving plate that is disposed around the sensor chip and to which an external force is applied, (iii) a base that supports the sensor chip, (iv) an external force-buffering mechanism that secures the external force receiving plate to the base, and (v) a coupling rod that is an external force-transmitting mechanism, where the external force receiving plate and an effect portion are coupled to each other by the coupling rod. 
     The sensor chip includes (i) the effect portion that is substantially square-shaped and is located in a central portion, (ii) a ring-shaped support that is square at a location surrounding the effect portion, and (iii) four T-shaped coupling portions that are each located between the effect portion and the support, where each T-shaped coupling portion is provided with respect to a corresponding side among four sides of the sensor chip, and couples the effect portion and the support. Each of the four coupling portions is a T-shaped beam having a bridge beam portion and an elastic portion (see, e.g., Patent Document 1). 
     CITATION LIST 
     [Patent Document]
     Patent Document 1: Japanese Unexamined Patent Application Publication No. 2003-254843   

     SUMMARY 
     In recent years, there is demand for force sensor devices having greater rating capacity. However, a strain inducing body that constitutes such a force sensor device having the greater rating capacity is displaced greatly in comparison to a compact force sensor device. Thus, in a structure of a sensor chip used in the force sensor device, there are one or more beams that cannot greatly deform when the strain inducing body is displaced in a particular direction, and consequently the one or more beams may be broken. 
     In view of the point described above, an object of the present disclosure is to provide a sensor chip with increased fracture resistance of a beam when displacement in various directions occurs. 
     A sensor chip includes multiple sensing blocks each of which includes two or more T-patterned beam structures. Each T-patterned beam structure includes strain-detecting elements, at least one first detection beam, and a second detection beam extending from the first detection beam in a direction perpendicular to the first detection beam. Each T-patterned beam structure includes a connection portion formed by coupling ends of second detection beams in respective T-patterned structures, the connection portion including a force point portion. The sensor chip is configured to detect up to six axes relating to predetermined axial forces or moments around the predetermined axes, based on a change in an output of each of the strain-detecting elements, the output of each strain-detecting element changing in accordance with an input applied to a given force point portion. 
     According to the disclosed technique, a sensor chip that improves fracture resistance of a beam with respect to displacements in various directions can be provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a force sensor device according to a first embodiment; 
         FIG.  2    is a cross-sectional perspective view of the force sensor device according to the first embodiment; 
         FIG.  3    is a perspective top view of a sensor chip attached to an input transmitter; 
         FIG.  4    is a perspective bottom view of the sensor chip attached to the input transmitter; 
         FIG.  5    is a perspective view of a sensor chip  100  when viewed in a positive Z-axis direction; 
         FIG.  6    is a plan view of the sensor chip  100  when viewed in the positive Z-axis direction; 
         FIG.  7    is a perspective view of the sensor chip  100  when viewed in a negative Z-axis direction; 
         FIG.  8    is a bottom view of the sensor chip  100  when viewed in the negative Z-axis direction; 
         FIG.  9    is a diagram for describing signs for forces and moments applied to axes; 
         FIG.  10    is a diagram illustrating an example of the arrangement of piezoresistive elements of the sensor chip  100 ; 
         FIG.  11    is a partial enlarged view of the sensor chip in one sensing block illustrated in  FIG.  10   ; 
         FIG.  12    is a diagram (first part) illustrating an example of a detecting circuit that uses piezoresistive elements; 
         FIG.  13    is a diagram (second part) illustrating an example of the detecting circuit that uses piezoresistive elements; 
         FIG.  14    is a diagram for describing an input Fx; 
         FIG.  15    is a diagram for describing an input Fy; 
         FIG.  16    is a diagram illustrating a simulation result when the input Fx is applied to the sensor chip; 
         FIG.  17    is a diagram illustrating a simulation result when an input Mz is applied to the sensor chip; 
         FIG.  18    is a diagram illustrating a simulation result when an input Fz is applied to the sensor chip; 
         FIG.  19    is a partial perspective view of the sensor chip illustrated in  FIG.  18   ; 
         FIG.  20    is a perspective view of a force receiving plate included in a strain inducing body; 
         FIG.  21    is a perspective view of a strain inducing portion included in the strain inducing body; 
         FIG.  22    is a perspective top view of an input transmitter included in the strain inducing body; 
         FIG.  23    is a perspective bottom view of the input transmitter included in the strain inducing body; 
         FIG.  24    is a side view of the input transmitter included in the strain inducing body; 
         FIG.  25    is a perspective view of a cover plate included in the strain inducing body; 
         FIG.  26    is a diagram illustrating the simulation result when the input Fx is applied to the strain inducing portion; 
         FIG.  27    is a diagram illustrating the simulation result when the input Mz is applied to the strain induction section; 
         FIG.  28    is a plan view of a sensor chip  100 A when viewed in the positive Z-axis direction; 
         FIG.  29    is a partial plan view of a sensor chip  100 B when viewed in the positive Z-axis direction; 
         FIG.  30    is a partial plan view of a sensor chip  100 C when viewed in the positive Z-axis direction; 
         FIG.  31    is a perspective view of a strain inducing body  200 A; 
         FIG.  32    is a cross-sectional perspective view of the strain inducing body  200 A; 
         FIG.  33    is a perspective view of the input transmitter included in the strain inducing body; 
         FIG.  34    is a perspective view of the cover plate included in the strain inducing body; 
         FIG.  35    is a side view of a strain inducing body  200 B; and 
         FIG.  36    is a perspective bottom view of the strain inducing portion included in the strain inducing body. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     One or more embodiments will be described with reference to the drawings. In each figure, the same components are indicated by the same numerals, and description thereof may be omitted. 
     First Embodiment 
     (Schematic Configuration of Force Sensor Device  1 ) 
       FIG.  1    is a perspective view of a force sensor device according to a first embodiment.  FIG.  2    is a cross-sectional perspective view of the force sensor device according to the first embodiment. Referring to  FIG.  1    and  FIG.  2   , the force sensor device  1  includes a sensor chip  100  and a strain inducing body  200 . The force sensor device  1  is, for example, a multi-axis force sensor device provided in an arm, a finger, or the like of a robot that is used for a machine tool or the like. 
     The sensor chip  100  has a function of detecting up to six axes relating to displacements in predetermined axial directions. The strain inducing body  200  has a function of transmitting at least one among an applied force and a moment, to the sensor chip  100 . In the following description of embodiments, for example, a case in which the sensor chip  100  detects six axes will be described, but there is no limitation to such a sensor chip. For example, the sensor chip  100  that detects three axes or the like can be adopted. 
     The strain inducing body  200  includes a force receiving plate  210 , a strain inducing portion  220 , an input transmitter  230 , and a cover plate  240 . The strain inducing portion  220  is layered on the force receiving plate  210 , the input transmitter  230  is layered on the strain inducing portion  220 , and the cover plate  240  is layered on the input transmitter  230 . The strain inducing body  200  is substantially cylindrical as a whole. The function of the strain inducing body  200  is mainly implemented by the strain inducing portion  220  and the input transmitter  230 , and thus the force receiving plate  210  and the cover plate  240  may be provided as needed. 
     In the present embodiment, for the sake of convenience, for the force sensor device  1 , the side of the cover plate  240  is referred to as a top side or one side, and the side of the force receiving plate  210  is referred to as a bottom side or another side. Further, for each component, the surface on the side of the cover plate  240  is referred to as one surface or a top surface, and the surface on the side of the force receiving plate  210  is referred to as another surface or a bottom surface. The force sensor device  1  may be used in a state of being upside down, or can be disposed at any angle. A plan view means that an object is viewed in a direction (Z-axis direction) normal to the top surface of the cover plate  240 , and a planar shape refers to a shape of the object when viewed in the direction (Z-axial direction) normal to the top surface of the cover plate  240 . 
       FIG.  3    is a perspective top view of the sensor chip attached to the input transmitter.  FIG.  4    is a perspective bottom view of the sensor chip attached to the input transmitter. As illustrated in  FIG.  3    and  FIG.  4   , an accommodating portion that protrudes from the bottom surface of the input transmitter  230 , toward the strain inducing portion  220 , is provided in the input transmitter  230 . The sensor chip  100  is secured to the accommodating portion  235  toward the cover plate  240 . 
     Specifically, as described below, four second connection portions  235   c  (see  FIGS.  22  to  24    and the like below) each of which enters the cover plate  240  are disposed in the accommodating portion  235 . The second connection portions  235   c  are respectively connected to the bottom surfaces of force point portions  151  to  154  (see  FIGS.  5  to  8    and the like below) of the sensor chip  100 . 
     The accommodating portion  235  enters the strain inducing portion  220 . As described below, first connection portions  224  (see  FIG.  21    below), which are five columnar portions and protrude toward the input transmitter  230 , are disposed in the strain inducing portion  220 . The first connection portions  224  are respectively connected to bottom surfaces of the supports  101  to  105  (see  FIGS.  5  to  8    and the like below) in the sensor chip  100 . 
     The sensor chip  100  and the strain inducing body  200  will be described below in detail. In the following description, the word “parallel” is intended to include a case in which an angle between two straight lines or sides is in the range of 0°±10°. The word “vertical” or “perpendicular” is intended to include a case in which an angle between two straight lines or between sides is in the range of 90°±10°. However, when a special specification is described, it is applied. The word “center” and “middle” are intended to include an approximate center and middle of an object, and are not intended to mean only an exact center and middle. In other words, variations in manufacturing error shall be tolerable. The same applies to point symmetry and line symmetry. 
     (Sensor Chip  100 ) 
       FIG.  5    is a perspective view of the sensor chip  100  when viewed in the positive Z-axis direction.  FIG.  6    is a plan view of the sensor chip  100  when viewed in the positive Z-axis direction.  FIG.  7    is a perspective view of the sensor chip  100  when viewed in the negative Z-axis direction.  FIG.  8    is a bottom view of the sensor chip  100  when viewed in the negative Z-axis direction. In  FIG.  8   , for the sake of convenience, surfaces at the same height are illustrated in the same crepe pattern. In this description, a direction parallel to one side of the top surface of the sensor chip  100  refers to the X-axis direction, a direction perpendicular to the one side of the top surface of the sensor chip  100  refers to the Y-axis direction, and a thickness direction (direction normal to the top surface of the sensor chip  100 ) of the sensor chip  100  refers to the Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are mutually perpendicular. 
     The sensor chip  100  illustrated in  FIGS.  5  to  8    is a microelectromechanical systems (MEMS) sensor chip that is one chip and can detect up to six axes. The sensor chip  100  is formed of a semiconductor substrate such as a silicon on insulator (SOI) substrate. The planar shape of the sensor chip  100  can be, for example, an approximate 7000 μm per side rectangle (square or rectangle). 
     The sensor chip  100  includes five columnar supports  101  to  105 . The planar shape of each of the supports  101  to  105  can be, for example, an approximate 2000 μm per side square. The supports  101  to  104  are respectively disposed at four corners of the rectangular sensor chip  100 . The support  105  is disposed on a central portion of the rectangular sensor chip  100 . Each of the supports  101  to  104  is a representative example of a first support, and the support  105  is a representative example of a second support. 
     A frame  112  (for coupling supports that are next to each other), of which both ends are fixed by the support  101  and the support  102 , is provided between the support  101  and the support  102 . A frame  113  (for coupling supports that are next to each other), of which both ends are fixed by the support  102  and the support  103 , is provided between the support  102  and the support  103 . 
     A frame  114  (for coupling supports that are next to each other), of which both ends are fixed by the support  103  and the support  104 , is provided between the support  103  and the support  104 . A frame  111  (for coupling supports that are next to each other), of which both ends are fixed by the support  104  and the support  101 , is provided between the support  104  and the support  101 . 
     In other words, four frames  111 ,  112 ,  113 , and  114  are formed as a structural frame of the sensor chip  100 , and the supports  101 ,  102 ,  103 , and  104  are each disposed at a corner at which given frames are coupled to each other. 
     An internal corner of the support  101  and a corner of the support  105  facing the internal corner of the support  101  are coupled by a coupling portion  121 . An internal corner of the support  102  and a corner of the support  105  facing the internal corner of the support  102  are coupled by a coupling portion  122 . 
     An internal corner of the support  103  and a corner of the support  105  facing the internal corner of the support  103  are coupled by a coupling portion  123 . An internal corner of the support  104  and a corner of the support  105  facing the internal corner of the support  104  are coupled by a coupling portion  124 . 
     In such a manner, the sensor chip  100  includes the coupling portions  121  to  124  each of which couples the support  105  and a given support among the supports  101  to  104 . The coupling portions  121  to  124  are each disposed diagonally relative to the X-axis direction (Y-axis direction). The coupling portions  121  to  124  are respectively disposed so as not to be parallel to the frames  111 ,  112 ,  113 , and  114 . 
     The supports  101  to  105 , the frames  111  to  114 , and the coupling portions  121  to  124  can be each formed of, for example, an active layer, a BOX layer, and a support layer of the SOI substrate. The thickness of each of those layers can be, for example, in the range of about 400 μm to about 600 μm. 
     The sensor chip  100  has four sensing blocks B 1  to B 4 . Each sensing block includes three T-patterned beam structures in each of which piezoresistive elements being strain-detecting elements are disposed. The T-patterned beam structure refers to a structure that includes a first detection beam and a second detection beam that extends from a middle portion of the first detection beam in a direction perpendicular to the first detection beam. 
     Specifically, the sensing block B 1  includes T-patterned beam structures  131 T 1 ,  131 T 2 , and  131 T 3 . The sensing block B 2  includes T-patterned beam structures  132 T 1 ,  132 T 2 , and  132 T 3 . The sensing block B 3  includes T-patterned beam structures  133 T 1 ,  133 T 2 , and  133 T 3 . The sensing block B 4  includes T-patterned beam structures  134 T 1 ,  134 T 2 , and  134 T 3 . The beam structure will be described below in more details. 
     In the sensing block B 1 , in a plan view, a first detection beam  131   a  is provided parallel to a side of the support  104  toward the support  101  so as to be at a predetermined distance from the side of the support  104 . The first detection beam  131   a  extends between the frame  111 , toward the support  101 , and the coupling portion  121 , toward the support  105 . A second detection beam  131   b  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  131   a  in a longitudinal direction of the first detection beam. The second detection beam  131   b  extends toward the support  104  in a direction perpendicular to the longitudinal direction of the first detection beam  131   a . The first detection beam  131   a  and the second detection beam  131   b  constitute the T-patterned beam structure  131 T 1 . 
     In a plan view, a first detection beam  131   c  is provided parallel to a side of the support  104  toward the support  101  so as to be at a predetermined distance from the side of the support  104 . The first detection beam  131   c  extends between the coupling portion  111 , toward the support  104 , and the coupling portion  124 , toward the support  105 . A second detection beam  131   d  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  131   c  in a longitudinal direction of the first detection beam. The second detection beam  131   d  extends toward the support  101  in a direction perpendicular to the longitudinal direction of the first detection beam  131   c . The first detection beam  131   c  and the second detection beam  131   d  constitute the T-patterned beam structure  131 T 2 . 
     In a plan view, a first detection beam  131   e  is provided parallel to a side of the support  105  toward the frame  111  so as to be at a predetermined distance from the side of the support  105 . The first detection beam  131   e  extends between the coupling portion  121 , toward the support  105 , and the coupling portion  124 , toward the support  105 . A second detection beam  131   f  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  131   e  in a longitudinal direction, and the second detection beam  131   f  extends toward the frame  111  in a direction perpendicular to the longitudinal direction of the first detection beam  131   e . The first detection beam  131   e  and the second detection beam  131   f  constitute the T-patterned beam structure  131 T 3 . 
     Another end of the second detection beam  131   b , another end of the second detection beam  131   d , and another end of the second detection beam  131   f  are connected to one another to thereby form a connection portion  141 . A force point portion  151  is provided at the bottom surface of the connection portion  141 . The force point portion  151  has, for example, a rectangular prismatic shape. The T-patterned beam structures  131 T 1 ,  131 T 2 , and  131 T 3 , the connection portion  141 , and the force point portion  151  constitute the sensing block B 1 . 
     In the sensing block B 1 , the first detection beam  131   a , the first detection beam  131   c , and the second detection beam  131   f  are parallel to one another. Also, the second detection beams  131   b  and  131   d , and the first detection beam  131   e  are parallel to one another. The thickness of each detection beam in the sensing block B 1  can be, for example, in the range of about 30 μm to about 50 μm. 
     In the sensing block B 2 , in a plan view, a first detection beam  132   a  is provided parallel to a side of the support  102  toward the support  101  so as to be at a predetermined distance from the side of the support  102 . The first detection beam  132   a  extends between the frame  112 , toward the support  102 , and the coupling portion  122 , toward the support  105 . A second detection beam  132   b  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  132   a  in a longitudinal direction of the first detection beam. The second detection beam  132   b  extends toward the support  101  in a direction perpendicular to the longitudinal direction of the first detection beam  132   a . The first detection beam  132   a  and the second detection beam  132   b  constitute the T-patterned beam structure  131 T 2 . 
     In a plan view, a first detection beam  132   c  is provided parallel to a side of the support  101  toward the support  102  so as to be at a predetermined distance from the side of the support  101 . The first detection beam  132   c  extends between the frame  112 , toward the support  101 , and the coupling portion  121 , toward the support  105 . A second detection beam  132   d  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  132   c  in a longitudinal direction of the first detection beam. The second detection beam  132   d  extends toward the support  102  in a direction perpendicular to the longitudinal direction of the first detection beam  132   c . The first detection beam  132   c  and the second detection beam  132   d  constitute the T-patterned beam structure  132 T 2 . 
     In a plan view, a first detection beam  132   e  is provided parallel to a side of the support  105  toward the frame  112  so as to be at a predetermined distance from the side of the support  105 . The first detection beam  132   e  extends between the coupling portion  122 , toward the support  105 , and the coupling portion  121 , toward the support  105 . A second detection beam  132   f  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  132   e  in a longitudinal direction, and the second detection beam  132   f  extends toward the frame  111  so as to be perpendicular to the longitudinal direction of the first detection beam  132   e . The first detection beam  132   e  and the second detection beam  132   f  constitute the T-patterned beam structure  132 T 3 . 
     Another end of the second detection beam  132   b , another end of the second detection beam  132   d , and another end of the second detection beam  132   f  are connected to one another to thereby form a connection portion  142 . A force point portion  152  is provided at the bottom surface of the connection portion  142 . The force point portion  152  has, for example, a rectangular prismatic shape. The T-patterned beam structures  132 T 1 ,  132 T 2 , and  132 T 3 , the connection portion  142 , and the force point portion  152  constitute the sensing block B 2 . 
     In the sensing block B 2 , the first detection beam  132   a , the first detection beam  132   c , and the second detection beam  132   f  are parallel to one another. Also, the second detection beams  132   b  and  132   d , and the first detection beam  132   e  are parallel to one another. The thickness of each detection beam in the sensing block B 2  may be, for example, in the range of about 30 μm to about 50 μm. 
     In the sensing block B 3 , in a plan view, a first detection beam  133   a  is provided parallel to a side of the support  103  toward the support  102  so as to be at a predetermined distance from the side of the support  103 . The first detection beam  133   a  extends between the frame  113 , toward the support  103 , and the coupling portion  123 , toward the support  105 . A second detection beam  133   b  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  133   a  in a longitudinal direction of the first detection beam. The second detection beam  133   b  extends toward the support  102  in a direction perpendicular to the longitudinal direction of the first detection beam  133   a . The first detection beam  133   a  and the second detection beam  133   b  constitute the T-patterned beam structure  133 T 1 . 
     In a plan view, a first detection beam  133   c  is provided parallel to a side of the support  102  toward the support  103  so as to be at a predetermined distance from the side of the support  102 . The first detection beam  133   c  extends between the frame  113 , toward the support  102 , and the coupling portion  122 , toward the support  105 . A second detection beam  133   d  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  133   c  in a longitudinal direction of the first detection beam. The second detection beam  131   d  extends toward the support  103  in a direction perpendicular to the longitudinal direction of the first detection beam  133   c . The first detection beam  133   c  and the second detection beam  133   d  constitute the T-patterned beam structure  133 T 2 . 
     In a plan view, a first detection beam  131   e  is provided parallel to a side of the support  105  toward the frame  111  so as to be at a predetermined distance from the side of the support  105 . The first detection beam  131   e  extends between the coupling portion  121 , toward the support  105 , and the coupling portion  124 , toward the support  105 . A second detection beam  131   f  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  131   e  in a longitudinal direction, and the second detection beam  131   f  extends toward the frame  111  so as to be perpendicular to the longitudinal direction of the first detection beam  131   e . The first detection beam  131   e  and the second detection beam  131   f  constitute the T-patterned beam structure  131 T 3 . 
     Another end of the second detection beam  133   b , another end of the second detection beam  133   d , and another end of the second detection beam  133   f  are connected to one another to thereby form a connection portion  143 . A force point portion  153  is provided at the bottom surface of the connection portion  143 . The force point portion  153  has, for example, a rectangular prismatic shape. The T-patterned beam structures  133 T 1 ,  133 T 2 , and  133 T 3 , the connection portion  143 , and the force point portion  153  constitute the sensing block B 3 . 
     In the sensing block B 3 , the first detection beam  133   a , the first detection beam  133   c , and the second detection beam  133   f  are parallel to one another. Also, the second detection beams  133   b  and  133   d , and the first detection beam  133   e  are parallel to one another. The thickness of each detection beam in the sensing block B 3  may be, for example, in the range of about 30 μm to about 50 μm. 
     In the sensing block B 4 , in a plan view, a first detection beam  134   a  is provided parallel to a side of the support  104  toward the support  103  so as to be at a predetermined distance from the side of the support  104 . The first detection beam  134   a  extends between the frame  114 , toward the support  104 , and the coupling portion  124 , toward the support  105 . A second detection beam  134   b  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  134   a  in a longitudinal direction of the first detection beam. The second detection beam  134   b  extends toward the support  103  in a direction perpendicular to the longitudinal direction of the first detection beam  134   a . The first detection beam  134   a  and the second detection beam  134   b  constitute the T-patterned beam structure  134 T 1 . 
     In a plan view, a first detection beam  134   c  is provided parallel to a side of the support  103  toward the support  104  so as to be at a predetermined distance from the side of the support  103 . The first detection beam  134   c  extends between the frame  114 , toward the support  103 , and the coupling portion  123 , toward the support  105 . A second detection beam  134   d  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  134   c  in a longitudinal direction of the first detection beam. The second detection beam  131   d  extends toward the support  104  in a direction perpendicular to the longitudinal direction of the first detection beam  134   c . The first detection beam  134   c  and the second detection beam  134   d  constitute the T-patterned beam structure  134 T 2 . 
     In a plan view, a first detection beam  134   e  is provided parallel to a side of the support  105  toward the frame  114  so as to be at a predetermined distance from the side of the support  105 . The first detection beam  134   e  extends between the coupling portion  124 , toward the support  105 , and the coupling portion  123 , toward the support  105 . A second detection beam  134   f  is provided such that one end of the second detection beam is coupled at a middle portion of the first detection beam  134   e  in a longitudinal direction, and the second detection beam  131   f  extends toward the frame  114  so as to be perpendicular to the longitudinal direction of the first detection beam  134   e . The first detection beam  134   e  and the second detection beam  134   f  constitute the T-patterned beam structure  134 T 3 . 
     Another end of the second detection beam  134   b , another end of the second detection beam  134   d , and another end of the second detection beam  134   f  are connected to one another to thereby form a connection portion  144 . A force point portion  154  is provided at the bottom surface of the connection portion  144 . The force point portion  154  has, for example, a rectangular prismatic shape. The T-patterned beam structures  134 T 1 ,  134 T 2 , and  134 T 3 , the connection portion  144 , and the force point portion  154  constitute the sensing block B 4 . 
     In the sensing block B 4 , the first detection beam  134   a , the first detection beam  134   c , and the second detection beam  134   f  are parallel to one another. Also, the second detection beams  134   b  and  134   d , and the first detection beam  134   e  are parallel to one another. The thickness of each detection beam in the sensing block B 4  may be, for example, in the range of about 30 μm to about 50 μm. 
     Thus, the sensor chip  100  includes the four sensing blocks (sensing blocks B 1  to B 4 ). Each sensing block is disposed in a region surrounded by (i) given supports that are next to each other and are among the supports  101  to  104 , (ii) a given frame and a given coupling portion each of which couples the given supports that are next to each other, and (iii) the support  105 . In a plan view, for example, given sensing blocks can be disposed to be point-symmetric with respect to the center of the sensor chip. 
     Each sensing block includes three T-patterned beam structures. In each sensing block, three T-patterned beam structures include two T-patterned beam structures in which, in a plan view, a given connection portion is interposed between first detection beams that are respectively included in two T-patterned beam structures and are disposed parallel to each other. The three T-beam structures also include one T-patterned beam structure including a first detection beam that is disposed parallel to second detection beams included in the respective two T-patterned beam structures. The first detection beam in the one T-patterned beam structure is disposed between the given connection portion and the support  105 . 
     For example, in the sensing block B 1 , three T-patterned beam structures include T-patterned beam structures  131 T 1  and  131 T 2  in which, in a plan view, the connection portion  141  is interposed between the first detection beam  131   a  and the first detection beam  131   c  that are disposed parallel to each other. The three T-patterned beam structures also include the T-patterned beam structure  131 T 3  including the first detection beam  131   e  that is disposed parallel to the second detection beams  131   b  and  131   d  included in the respective T-patterned beam structures  131 T 1  and  131 T 2 . The first detection beam  131   e  in the T-patterned beam structure  131 T 3  is disposed between the connection portion  141  and the support  105 . The structure in each of the sensing blocks B 2  to B 4  is similar to that in the sensing block B 1 . 
     Each of the force point portions  151  to  154  is a point to which an external force is applied. Each force point portion can be formed of, for example, a BOX layer and a support layer in the SOI substrate. The bottom surface of each of the force point portions  151  to  154  substantially corresponds to the bottom surface of a corresponding support among the supports  101  to  105 . 
     In such a manner, when a force or displacement is obtained through each of the four force point portions  151  to  154 , a given beam deforms so as to differ according to a force type, thereby providing a sensor with greater isolation of 6 axes. The number of force point portions is the same as the number of positions of the strain inducing body to which displacements are input. 
     One or more internal corners of the sensor chip  100  are preferably R-shaped in order to suppress stress concentration. 
     The supports  101  to  105  in the sensor chip  100  are connected to a non-movable portion in the strain inducing body  200 , and the force point portions  151  to  154  are connected to a movable portion of the strain inducing body  200 . Even if the movable portion and non-movable portion are reversed with respect to each other, the sensor chip  100  functions as a force sensor device. That is, the supports  101  to  105  in the sensor chip  100  are connected to the movable portion of the strain inducing body  200 , and the force point portions  151  to  154  may be connected to the non-movable portion of the strain inducing body  200 . 
       FIG.  9    is a diagram for describing signs for forces and moments applied to axes. As illustrated in  FIG.  9   , the force in the X-axis direction is expressed by Fx, the force in the Y-axis direction is expressed by Fy, and the force in the Z-axis direction is expressed by Fz. Also, the moment to cause rotation about the X-axis as an axis is expressed by Mx, the moment to cause rotation about the Y-axis as an axis is expressed by My, and the moment to cause rotation about the Z-axis as an axis is expressed by Mz. 
       FIG.  10    is a diagram illustrating the arrangement of piezoresistive elements in the sensor chip  100 .  FIG.  11    is an enlarged partial view of one sensing block in the sensor chip illustrated in  FIG.  10   . As illustrated in  FIG.  10    and  FIG.  11   , piezoresistive elements are each disposed at a predetermined location of a given sensing block corresponding to a force point portion among the four force point portions  151  to  154 . The arrangement of the piezoresistive elements in each of the other sensing blocks illustrated in  FIG.  10    is the same as that of the piezoresistive elements in the sensing block illustrated in  FIG.  11   . 
     Referring to  FIGS.  5  to  8   ,  FIG.  10   , and  FIG.  11   , in the sensing block B 1  that includes the connection portion  141  and the force point portion  151 , a piezoresistive element MzR 1 ′ is disposed at a portion of the first detection beam  131   a  that is toward the second detection beam  131   b  and is between the second detection beam  131   b  and the first detection beam  131   e . A piezoresistive element FxR 3  is disposed at a portion of the first detection beam  131   a  that is toward the first detection beam  131   e  and is between the second detection beam  131   b  and the first detection beam  131   e . A piezoresistive element MxR 1  is disposed on the second detection beam  131   b  toward the connection portion  141 . 
     A piezoresistive element MzR 2 ′ is disposed at a portion of the first detection beam  131   c  that is toward the second detection beam  131   d  and is between the second detection beam  131   d  and the first detection beam  131   e . A piezoresistive element FxR 1  is disposed at a portion of the first detection beam  131   c  that is toward the first detection beam  131   e  and is between the second detection beam  131   d  and the first detection beam  131   e . A piezoresistive element MxR 2  is disposed on the second detection beam  131   d  toward the connection portion  141 . 
     A piezoresistive element FzR 1 ′ is disposed on the second detection beam  131   f  toward the connection portion  141 . A piezoresistive element FzR 2 ′ is disposed on the second detection beam  131   f  toward the first detection beam  131   e . The piezoresistive elements MzR 1 ′, FxR 3 , MxR 1 , MzR 2 ′, FxR 1 , and MxR 2  are each disposed at a location apart from a middle portion of a corresponding detection beam in a longitudinal direction. 
     In the sensing block B 2  that includes the connection portion  142  and the force point portion  152 , a piezoresistive element MzR 4  is disposed at a portion of the first detection beam  132   a  that is toward the second detection beam  132   b  and is between the second detection beam  132   b  and the first detection beam  132   e . A piezoresistive element FyR 3  is disposed at a portion of the first detection beam  132   a  that is toward the first detection beam  132   e  and is between the second detection beam  132   b  and the first detection beam  132   e . A piezoresistive element MyR 4  is disposed on the second detection beam  132   b  toward the connection portion  142 . 
     A piezoresistive element MzR 3  is disposed at a portion of the first detection beam  132   c  that is toward the second detection beam  132   d  and is between the second detection beam  132   d  and the first detection beam  132   e . A piezoresistive element FyR 1  is disposed at a portion of the first detection beam  132   c  that is toward the first detection beam  132   e  and is between the second detection beam  132   d  and the first detection beam  132   e . A piezoresistive element MyR 3  is disposed on the second detection beam  132   d  toward the connection portion  142 . 
     A piezoresistive element FzR 4  is disposed on the second detection beam  132   f  toward the connection portion  142 . A piezoresistive element FzR 3  is disposed on the second detection beam  132   f  toward the first detection beam  132   e . The piezoresistive elements MzR 4 , FxR 3 , MyR 4 , MzR 3 , FyR 1 , and MyR 3  are each disposed at a location apart from a middle portion of a corresponding detection beam in a longitudinal direction. 
     In the sensing block B 3  that includes the connection portion  143  and the force point portion  153 , a piezoresistive element MzR 4 ′ is disposed at a portion of the first detection beam  133   a  that is toward the second detection beam  133   b  and is between the second detection beam  133   b  and the first detection beam  133   e . A piezoresistive element FxR 2  is disposed at a portion of the first detection beam  133   a  that is toward the first detection beam  133   e  and is between the second detection beam  133   b  and the first detection beam  133   e . A piezoresistive element MxR 4  is disposed on the second detection beam  133   b  toward the connection portion  143 . 
     A piezoresistive element MzR 3 ′ is disposed at a portion of the first detection beam  133   c  that is toward the second detection beam  133   d  and is between the second detection beam  133   d  and the first detection beam  133   e . A piezoresistive element FxR 4  is disposed at a portion of the first detection beam  133   c  that is toward the first detection beam  133   e  and is between the second detection beam  133   d  and the first detection beam  133   e . A piezoresistive element MxR 3  is disposed on the second detection beam  133   d  toward the connection portion  143 . 
     A piezoresistive element FzR 4 ′ is disposed on the second detection beam  133   f  toward the connection portion  143 . A piezoresistive element FzR 3 ′ is disposed on the second detection beam  133   f  toward the first detection beam  133   e . The piezoresistive elements MzR 4 ′, FxR 2 , MxR 4 , MzR 3 ′, FxR 4 , and MxR 3  are each disposed at a location apart from a middle portion of a corresponding detection beam in a longitudinal direction. 
     In the sensing block B 4  that includes the connection portion  144  and the force point portion  154 , a piezoresistive element MzR 1  is disposed at a portion of the first detection beam  134   a  that is toward the second detection beam  134   b  and is between the second detection beam  134   b  and the first detection beam  134   e . A piezoresistive element FyR 2  is disposed at a portion of the first detection beam  134   a  that is toward the first detection beam  134   e  and is between the second detection beam  134   b  and the first detection beam  134   e . A piezoresistive element MyR 1  is disposed on the second detection beam  132   b  toward the connection portion  144 . 
     A piezoresistive element MzR 2  is disposed at a portion of the first detection beam  134   c  that is toward the second detection beam  134   d  and is between the second detection beam  134   d  and the first detection beam  134   e . A piezoresistive element FyR 4  is disposed at a portion of the first detection beam  134   c  that is toward the first detection beam  134   e  and is between the second detection beam  134   d  and the first detection beam  134   e . A piezoresistive element MyR 2  is disposed on the second detection beam  134   d  toward the connection portion  144 . 
     A piezoresistive element FzR 1  is disposed on the second detection beam  134   f  toward the connection portion  144 . A piezoresistive element FzR 2  is disposed on the second detection beam  134   f  toward the first detection beam  134   e . The piezoresistive elements MzR 1 , FxR 2 , MyR 3 , MyR 1 , FzR 2 , and MyR 2  are each disposed at a location apart from a middle portion of a corresponding detection beam in a longitudinal direction. 
     In such a manner, in the sensor chip  100 , each of the sensing blocks individually includes multiple piezoresistive elements. With this arrangement, when inputs are respectively applied to the force point portions  151  to  154 , the sensor chip  100  can detect up to six axes relating to forces in predetermined axis-directions or moments about respective predetermined axes, based on changes in the outputs of multiple piezoresistive elements on given beams. 
     In addition to the piezoresistive elements used to detect strain, one or more dummy piezoresistive elements may be disposed in the sensor chip  100 . The dummy piezoresistive elements are used to adjust variations in stress against detection beams or resistance of a bridge circuit. For example, all piezoresistive elements including piezoresistive elements used to detect strain are arranged so as to be point-symmetrical with respect to the center of the support  105 . 
     In the sensor chip  100 , each piezoresistive element among multiple piezoresistive elements to detect the displacement in the X-axis direction and the displacement in the Y-axis direction is disposed on the first detection beam included in a given T-patterned beam structure, and further, each piezoresistive element among multiple piezoresistive elements to detect the displacement in the Z-axis direction is disposed on the second detection beam included in a given T-patterned beam structure. Furthermore, each piezoresistive element among multiple piezoresistive elements to detect moments about the Z-axis direction is disposed on the first detection beam included in a given T-patterned beam structure, and further, each piezoresistive element among multiple piezoresistive elements to detect moments about the X-axis direction and the Y-axis direction is disposed on the second detection beam included in a given T-patterned beam structure. 
     Each of the piezoresistive elements FxR 1  to FxR 4  detects the force Fx, each of the piezoresistive elements FyR 1  to FyR 4  detects the force Fy, and each of the piezoresistive elements FzR 1  to FzR 4  and FzR 1 ′ to FzR 4 ′ detects the force Fz. Also, each of the piezoresistive elements MxR 1  to MxR 4  detects the moment Mx, each of the piezoresistive elements MyR 1  to MyR 4  detects the moment My, and each of the piezoresistive elements MzR 1  to MzR 4  and MzR 1 ′ to MzR 4 ′ detects the moment Mz. 
     In such a manner, in the sensor chip  100 , each of the sensing blocks individually includes multiple piezoresistive elements. With this arrangement, when forces or displacements are respectively applied (transmitted) to the force point portions  151  to  154 , the sensor chip  100  can detect up to six axes relating to forces in predetermined directions or moments about the respective directions (axis-directions), based on changes in the outputs of multiple piezoresistive elements on given beams. By changing the thickness and width of each detection beam, equalization of detection sensitivity, increases in detection sensitivity, or the like can be controlled. 
     By reducing the number of piezoresistive elements, a sensor chip for detecting five axes or less relating to displacements in predetermined axis directions can be provided. 
     In the sensor chip  100 , for example, a detecting circuit described below can be used to detect forces and moments. Each of  FIG.  12    and  FIG.  13    illustrates an example of the detecting circuit that uses piezoresistive elements. In each of  FIG.  12    and  FIG.  13   , numbers rounded with squares indicate external output terminals. For example, the number “1” indicates a power supply terminal for a Fx-axis, a Fy-axis, and a Fz-axis. The number “2” is a negative output terminal for the Fx-axis. The number “3” indicates a GND terminal for the Fx-axis, and the number “4” indicates a positive output terminal for the Fx-axis. The number “19” indicates a negative output terminal for the Fy-axis, the number “20” indicates a GND terminal for the Fy-axis, and the number “21” indicates a positive output terminal for the Fy-axis. The number “22” indicates a negative output terminal for the Fz-axis, the number “23” indicates a GND terminal for the Fz-axis, and the number “24” indicates a positive output terminal for the Fz-axis. 
     The number “9” indicates a negative terminal for the Mx-axis, the number “10” indicates a GND terminal for the Mx-axis, and the number “11” indicates a positive output terminal for the Mx-axis. The number “12” indicates a power supply terminal for the Mx-axis, My-axis, and Mz-axis. The number “13” indicates a negative output terminal for the My-axis, the number “14” indicates a GND terminal for the My-axis, and the number “15” indicates a positive output terminal for the My-axis. The number “16” indicates a negative output terminal for the Mz-axis, the number “17” indicates a GND terminal for the Mz-axis, and the number “18” indicates a positive output terminal for the Mz-axis. 
     Hereafter, deformation of the detection beam will be described.  FIG.  14    is a diagram describing an input Fx.  FIG.  15    is a diagram for describing an input Fy. As illustrated in  FIG.  14   , when the input from the strain inducing body  200  to which the sensor chip  100  is attached is expressed by Fx, all of the four force point portions  151  to  154  attempt to move in the same direction (rightward direction in an example in  FIG.  14   ). Similarly, as illustrated in  FIG.  15   , when the input from the strain inducing body  200  to which the sensor chip  100  is attached is expressed by Fy, all four force point portions  151  to  154  attempt to move in the same direction (upward direction in an example in  FIG.  15   ). In this case, although the sensor chip  100  includes four sensing blocks, the respective force point portions in all sensing blocks move in the same direction, in accordance with displacements in the X-axis direction and Y-axis direction. 
       FIG.  16    is a diagram illustrating a simulation result obtained when the sensor chip receives the input Fx. When the inputs Fx expressed by the arrows in  FIG.  14    are applied, detection beams deform as illustrated in  FIG.  16   . In particular, it can be seen that one or more first detection beams (one or more beams in a lateral position in a given T-patterned beam structure) is greatly deformed in each sensing block. 
     In the sensor chip  100 , each T-patterned beam structure includes one or more first detection beams that are among all first detection beams in a given T-patterned beam structure and are perpendicular to a displacement direction of the input. With this arrangement, such first detection beams perpendicular to the displacement direction of the input can deform greatly, as illustrated in  FIG.  16   . In  FIG.  16   , the first detection beams, which are perpendicular to the displacement direction of the input, include the first detection beams  131   a ,  131   c ,  132   e ,  133   a ,  133   c , and  134   e  illustrated in  FIG.  6    and the like. 
     Beams used to detect the inputs Fx include the first detection beams  131   a ,  131   c ,  133   a , and  133   c . Each beam among those beams is a first detection beam in a given T-patterned beam structure, and is at a fixed distance from a given force point portion. The beams used to detect the inputs Fy include the first detection beams  132   a ,  132   c ,  134   a , and  134   c . Each beam among those beams is a first detection beam in a given T-patterned beam structure, and is at a distance from a given force point portion. 
     In response to inputs Fx and the inputs Fy, first detection beams, on which the piezoresistive elements are disposed and that are each included in a given T-patterned beam structure, deform greatly, thereby effectively detecting the input forces. Also, beams not used to detect the inputs are designed to be greatly deformable in accordance with the displacement occurring when the inputs Fx and Fy are applied. With this arrangement, even if at least one input among the input Fx and the input Fy is increased, none of the detection beams are broken. 
     Conventional sensor chips include beams not being able to deform greatly in accordance with at least one given input among the inputs Fx and the inputs Fy. Thus, when at least one input among the input Fx and the input Fy is increased, the beams not being deformed might be broken. The sensor chip  100  can address the issue described above. That is, the sensor chip  100  can have increased fracture resistance of beams, even when displacements in various directions occur. 
     As described above, the sensor chip  100  includes one or more first detection beams perpendicular to the displacement direction of each input, and the one or more first detection beams perpendicular to the displacement direction can greatly deform. With this arrangement, the input Fx and the input Fy can be effectively detected. Also, even if at least one input among the input Fx and the input Fy is increased, none of the detection beams are broken. As a result, the sensor chip  100  can be used for any increased rating capacity, and a measurement range and load bearing can be also improved. For example, the sensor chip  100  may have a rating capacity of 500N, which is about 10 times greater than that of conventional chips. 
     In each sensing block, beams each extending in three directions in a given T-patterned beam structure are coupled to one another at a given force point portion, and deform so as to differ according to inputs. Thus, multi-axial forces can be detected more separately. 
     When beams are arranged in the T pattern, an increased number of paths that are each from a given beam to either a given frame or a given coupling portion is obtained. With this arrangement, a line is easily drawn to the outer periphery of the sensor chip. Therefore, layout flexibility can be improved. 
       FIG.  17    is a simulation result when the input Mz is applied to the sensor chip. As illustrated in  FIG.  17   , for given two first detection beams, between which a given force point portion is disposed and that are among the first detection beams  131   a ,  131   c ,  132   a ,  132   c ,  133   a ,  133   c ,  134   a , and  134   c , the given first detection beams greatly deform in response to the moment about the Z-axis direction. With this arrangement, piezoresistive elements can be disposed on some or all of the first detection beams. 
       FIG.  18    is a simulation result when the input Fz is applied to the sensor chip.  FIG.  19    is a partial perspective view of the sensor chip illustrated in  FIG.  18   . As illustrated in  FIG.  18    and  FIG.  19   , for given two second detection beams, which are directly connected to a given force point portion and are among the second detection beams  131   b ,  131   d ,  131   f ,  132   b ,  132   d ,  132   f ,  133   b ,  133   d ,  133   f ,  134   b ,  134   d , and  134   f , the given two second detection beams mainly deform greatly in response to the displacement in the Z-axis direction. With this arrangement, piezoresistive elements can be disposed on some or all of the second detection beams. 
     (Strain Inducing Body  200 ) 
     As illustrated in  FIG.  1    and  FIG.  2   , the strain inducing body  200  includes the force receiving plate  210 , the strain inducing portion  220 , the input transmitter  230 , and the cover plate  240 . Each component of the strain inducing body  200  will be described below. 
       FIG.  20    is a perspective view of the force receiving plate included in the strain inducing body. As illustrated in  FIG.  20   , the force receiving plate  210  is a member that is substantially disk-shaped as a whole and receives the force and moment from a target object to be measured. The force receiving plate  210  includes an outer frame  211  that is substantially ring-shaped in a plan view, and includes a central portion  212  that is apart from the outer frame  211  and is disposed inside the outer frame  211 , where the central portion  212  is substantially circular in a plan view. The force receiving plate  210  also includes multiple beam structures  213  each of which couples the outer frame  211  and the central portion  212 . Even when the beam structure  213  causes increases in strength of the force receiving plate  210 , and the force or moment is received through the target object, deformation of the force receiving plate  210  itself is negligible. With this arrangement, without the losses in the deformation (displacement), the force or moment is transmitted to the strain inducing portion  220  that is connected to the central portion  212 . Through-holes  218  are each provided in a portion of the force receiving plate  210  that extends from the inside of the outer frame  211  toward each beam structure  213 . The through-holes  218  can be used for, for example, screwing the force receiving plate  210  into the target object. 
       FIG.  21    is a perspective view of the strain inducing portion included in the strain inducing body. As illustrated in  FIG.  21   , the strain inducing portion  220  is a substantially disk-shaped member as a whole, and deforms in response to receiving the force from the force receiving plate  210 . 
     The strain inducing portion  220  includes an outer frame  221  that is substantially ring-shaped in a plan view, and includes a central portion  222  that is apart from the outer frame  221  and is disposed inside the outer frame  221 , where the central portion  222  is substantially circular in a plan view. The strain inducing portion  220  also includes multiple beam structures  223  each of which couples the outer frame  221  and the central portion  222 . For example, given beam structures are disposed so as to be point-symmetric with respect to the center of the strain inducing portion  220 . The number of beam structures  223  is, for example, four. For example, each beam structure  223  includes a first beam and a second beam that extends from a middle portion of the first beam in a direction perpendicular to the first beam, where the first beam and the second beam are arranged in a T pattern. Both ends of the first beam are coupled to the outer frame  221 , and one end of the second beam is coupled to the central portion  222 . 
     The central portion  222  is formed to be thinner than the outer frame  221 , and each beam structure  223  is further thinner than the central portion  222 . The top surface of the central portion  222  and the top surface of each beam structure  223  are approximately the same plane and are located lower than the top surface of the outer frame  221 . The bottom surface of the central portion  222  protrudes slightly from the bottom surface of the outer frame  221 . The bottom surface of each beam structure  223  is located higher than the bottom surface of the outer frame  221  and the bottom surface of the central portion  222 . Only the beam structures  223  and the central portion  222  deform in response to receiving the force from the force receiving plate  210 , and the outer frame  221  does not deform. Although the central portion  222  moves in accordance with the deformation of each beam structure  223 , the central portion  222  itself does not deform. 
     A groove  220   x  is formed at the surface of the central portion  222  toward the input transmitter  230 . The shape of the groove  220   x  is a shape in which, in a plan view, a square groove portion overlaps with a cross-shaped groove portion that includes two elongated groove portions that are each longer than one side of the square groove portion and are perpendicular to each other. The depth of the square groove portion is the same as that of each cross-shaped groove portion. 
     First connection portions  224 , which include five columnar portions each protruding toward the input transmitter  230 , are respectively disposed at (i) four corners of the square groove portion other than the cross-shaped groove portion, and (ii) the center of the square groove portion. In this case, the first connection portions  224  do not contact an inner wall of the groove  220   x . Each first connection portion  224  is a portion connected to a given support among the supports  101  to  105  in the sensor chip  100 . The top surface of each first connection portion  224  is approximately in the same plane and is located lower than the top surface of the central portion  222  and the top surfaces of the beam structures  223 . Through-holes  228  are provided in the outer frame  221 . For example, with use of screws, the through-holes  228  can be used to secure the strain inducing portion  220 , the input transmitter  230 , and the cover plate  240 , to a fixed side (a robot-side or the like). 
     A space is provided toward the top surface of the central portion  222 . For example, a circuit board or the like that includes electronic components such as a connector and a semiconductor element may be disposed on the top surface of the central portion  222  so as not to enter the top surface of the outer frame  221 . 
       FIG.  22    is a perspective top view of the input transmitter included in the strain inducing body.  FIG.  23    is a perspective bottom view of the input transmitter included in the strain inducing body.  FIG.  24    is a side view of the input transmitter included in the strain inducing body. As illustrated in  FIGS.  22  to  24   , the input transmitter  230  is a member that is substantially disk-shaped as a whole and transmits deformation (input) of the strain inducing portion  220  to the sensor chip  100 . 
     The input transmitter  230  includes an outer frame  231  that is substantially ring-shaped in a plan view, and includes a central portion  232  that is apart from the outer frame  231  and is disposed inside the outer frame  231 . The input transmitter  230  also includes multiple beam structures  233  each of which couples the outer frame  231  and the central portion  232 . For example, given beam structures are disposed so as to be point-symmetric with respect to the center of the input transmitter  230 . The number of beam structures  233  is, for example, four. Each beam structure  233  is, for example, I-shaped. 
     The central portion  232  includes an inner frame  234  that is substantially ring-shaped in a plan view and is connected to each of the beam structures  233 . The central portion  232  also includes an accommodating portion  235  that is substantially cross-shaped in a plan view that extends from the bottom surface of the inner frame  234  toward the strain inducing portion  220 . The accommodating portion  235  includes four vertical supports  235   a  each of which extends vertically from the bottom surface of the inner frame  234  toward the strain inducing portion  220 . The accommodating portion  235  also includes four horizontal supports  235   b  each of which extends horizontally from the bottom end of a given vertical support  235   a  and is coupled at the center of the inner frame  234 . 
     The beam structures  233  and the inner frame  234  are each formed to be thinner than the outer frame  231 . The top surfaces of the beam structures  233  and the inner frame  234  are each disposed lower than the top surface of the outer frame  231 . The bottom surface of the outer frame  231 , the bottom surfaces of the beam structures  233 , and the bottom surface of the inner frame  234  are substantially in the same plane. The input transmitter  230  does not deform even when any component of the input transmitter  230  receives the force or moment. 
     In a plan view, given vertical supports among the four vertical supports  235   a  are disposed so as to be point-symmetric with respect to the center of the input transmitter  230 , and given horizontal supports among the four horizontal supports  235   b  are disposed so as to be point-symmetric with respect to the center of the input transmitter  230 . In a plan view, the longitudinal direction of each horizontal supports  235   b  is not the same as the longitudinal direction of a corresponding beam structure  233 . For example, in a plan view, the longitudinal direction of each horizontal support  235   b  and the longitudinal direction of a corresponding beam structure  233  are disposed at an offset by 45 degrees. 
     Grooves  235   x  are provided near the center of the substantially cross-shaped accommodating portion  235 , and the bottom surface of each groove  235   x  is arranged such that a corresponding second connection portion  235   c  protruding toward the cover plate  240  does not contact the inner wall of the groove  235   x . Each second connection portion  235   c  is substantially located on a line that is determined by bisecting a corresponding horizontal support  235   b  in the longitudinal direction. Each second connection portion  235   c  is a portion connected to a given force point portion among the force point portions  151  to  154  in the sensor chip  100 . Through-holes  238  are provided in the outer frame  231 . The through-holes  238  can be used to, for example, screw the strain inducing portion  220 , the input transmitter  230 , and the cover plate  240 , into the fixed side (robot-side or the like). 
     A space is provided toward the top surface of each beam structure  233 . For example, a circuit board or the like that includes electronic components such as a connector and a semiconductor element may be disposed on the top surface of each beam structure  233  so as not to enter the top surface of the outer frame  221 . 
       FIG.  25    is a perspective view of the cover plate included in the strain inducing body. As illustrated in  FIG.  25   , the cover plate  240  is a disk-like member as a whole and protects internal components (the sensor chip  100  and the like). The cover plate  240  is formed to be thinner than the force receiving plate  210 , the strain inducing portion  220 , and the input transmitter  230 . Through-holes  248  are provided in the cover plate  240 . For example, the through-holes  248  can be used to screw the strain-inducing portion  220 , the input transmitter  230 , and the cover plate  240 , to the fixed side (robot-side or the like). 
     For example, a hard metallic material, such as SUS (stainless steel), can be used as the material of each of the force receiving plate  210 , the strain inducing portion  220 , the input transmitter  230 , and the cover plate  240 . In this regard, it is preferable to use stainless steel of SUS 630 specified by the Japanese industrial standards (JIS). Such stainless steel is hard and has increased mechanical strength. For components included in the strain inducing body  200 , it is desirable for the force receiving plate  210 , the strain inducing portion  220 , and the input transmitter  230  to be firmly connected to one another, or to be integrally configured. As a method of connecting the force receiving plate  210 , the strain inducing portion  220 , and the input transmitter  230 , fastening may be performed with screws. Alternatively, welding or the like may be performed. In any case, those components of the strain inducing body  200  need to sufficiently withstand the force and moment that is input to the strain inducing body  200 . 
     In the present embodiment, for example, the force receiving plate  210 , the strain inducing portion  220 , and the input transmitter  230  are each fabricated by injection molding that uses metal powder, and then sintering of these fabricated components that are layered is again performed so that they are diffusion-welded. The force receiving plate  210 , the strain inducing portion  220 , and the input transmitter  230  that are diffusion-welded have necessary and sufficient welding strength. The cover plate  240  may be fastened to the input transmitter  230  by, for example, one or more screws, after mounting of the sensor chip  100  and other internal components. 
     When the force or moment is applied to the force receiving plate  210  in the strain inducing body  200 , the force or moment is transmitted to the central portion  222  of the strain inducing portion  220  connected to the force receiving plate  210 , and thus each of four beam structures  223  deforms in response to receiving a given input. In this case, the outer frame  221  and the input transmitter  230  in the strain inducing portion  220  do not deform. 
     In such a manner, in the strain inducing body  200 , each of the force receiving plate  210 , the central portion  222  of the strain inducing portion  220 , and the beam structures  223  is a movable portion that deforms in response to receiving a predetermined axial force or moment about a predetermined axis. The outer frame  221  of the strain inducing portion  220  is a non-movable portion that does not deform in response to receiving the force or moment. The input transmitter  230 , which is joined to the outer frame  221 , as a non-movable portion, of the strain inducing portion  220 , is a non-movable portion that does not deform in response to receiving the force or moment. Likewise, the cover plate  240 , which is joined to the input transmitter  230 , is a non-movable portion that does not deform in response to the force or moment. 
     When the strain inducing body  200  is used in the force sensor device  1 , the supports  101  to  105  of the sensor chip  100  are respectively connected to the first connection portions  224  provided on the central portion  222  that is a movable portion. Also, the force point portions  151  to  154  of the sensor chip  100  are respectively connected to the second connection portions  235   c  that are provided in the accommodating portion  235 , which is a non-movable portion. With this arrangement, the sensor chip  100  operates such that detection beams deform through the respective supports  101  to  105 , without the movement of the force point portions  151  to  154 . 
     In another example, the strain inducing body  200  may be configured, such that the force point portions  151  to  154  of the sensor chip  100  are respectively connected to the first connection portions  224  that are provided at the central portion  222 , which is a movable portion and such that the supports  101  to  105  of the sensor chip  100  are respectively connected to the second connection portions  235   c  that are provided in the accommodating portion  235 , which is a non-movable portion. 
     In such a case, the sensor chip  100  that can be accommodated in the accommodating portion  235  includes the supports  101  to  105  and the force point portions  151  to  154 , where the positional relationship between supports, as well as the positional relationship between force point portions, change in response to receiving a force or moment. In the strain inducing body  200 , the central portion  222  that is a movable portion includes first connection portions  224  each of which extends toward the input transmitter  230  and is connected to both a given support among the supports  101  to  105  and one end of a given force point portion among the force points  151  to  154 . The accommodating portion  235  includes second connection portions  235   c  each of which is connected to both the given support among the support  101  to  105  and another end of the given force portion among the force point portions  151  to  154 . 
       FIG.  26    is a diagram illustrating a simulation result when the input Fx is applied to the strain inducing portion.  FIG.  27    is a diagram illustrating a simulation result when the input Mz is applied to the strain inducing portion. As illustrated in  FIG.  26    and  FIG.  27   , it can be seen in both cases that four T-patterned beam structures  223  are deformed without the outer frame  221  of the strain inducing portion  220  being deformed. The same applies to a case where other inputs are applied. 
     With this arrangement, the strain inducing body  200  converts the input force or moment to a given displacement to thereby transmit it to the sensor chip  100  that is provided in the strain inducing body  200 . In conventional strain inducing bodies that have similar functions, a structure that receives forces and moments, as well as a structure that transmits displacements, are integrally configured or closely coupled to each other. For this reason, there is an increased trade-off between the displacement and load bearing and consequently it is particularly difficult to increase the load bearing. 
     In the strain inducing body  200 , the strain inducing portion  220  that receives forces and moments, as well as the input transmitter  230  that transmits the displacement to the sensor chip  100 , are formed as separate structures. With this arrangement, displacement can be appropriately detected, while increasing load bearing. 
     &lt;First Modification of the First Embodiment&gt; 
     A first modification of the first embodiment illustrates an example of the sensor chip having a different structure from that of the sensor chip described in the first embodiment. In the first modification of the first embodiment, description for the same configuration that has been the same as that in the above embodiments may be omitted. 
       FIG.  28    is a plan view of a sensor chip  100 A when viewed in the positive Z-axis direction. As illustrated in  FIG.  28   , the sensor chip  100 A has a detection beam structure as in the structure of the sensor chip  100  (see  FIG.  6    and the like). However, a space shape defined in the surroundings of each detection beam differs from that defined in the sensor chip  100 . In other words, in the sensor chip  100 A, opening widths of spaces provided at both sides of each detection beam are the same in a plan view. 
     In general, beam structures of sensor chips are formed using a silicon wafer in a semiconductor process, where a deep etch is performed by dry etching. If some opening widths in etched regions that are separated by detection beams are greater and are not the same, as in those determined in the shape of the sensor chip  100 , it might be more difficult to process the wafer, thereby resulting in reductions in processing quality. 
     In the sensor chip  100 A, an elongated etching region having the same opening width is formed over both sides of each detection beam. With this arrangement, when a deep etch is performed by dry etching, processing difficulty is reduced, thereby increasing processing quality. In  FIG.  28   , four circular openings are undercuts used to cause the sensor chip  100 A to prevent the contact with the strain inducing body  200 , when the sensor chip  100 A is attached to the strain inducing body  200 . If only efficiency in dry etching is considered, the four circular openings may not be provided. 
       FIG.  29    is a partial plan view of a sensor chip  100 B when viewed in the positive Z-axis direction. As illustrated in  FIG.  29   , the sensor chip  100 B differs from the sensor chip  100  (see  FIG.  6    and the like) in that one ends of respective second detection beams included in two T-patterned beam structures are connected to each other each at one end in the sensing block B 1 . In the sensor chip  100 , respective second detection beams included in three T-patterned beam structures are connected to one another each at one end. In contrast to the sensor chip  100 , the sensor chip  100 B does not include first detection beams  131   e ,  132   e ,  133   e , and  134   e , as well as second detection beams  131   f ,  132   f ,  133   f , and  134   f . The structure in each of sensing blocks B 2  to B 4  is the same as that in the sensing block B 1 . 
       FIG.  30    is a partial plan view of a sensor chip  100 C when viewed from the positive Z-axis direction. As illustrated in  FIG.  30   , the sensor chip  100 C differs from the sensor chip  100  (see  FIG.  6    and the like) in that respective second detection beams included in four T-patterned beam structures are connected to one another each at one end in the sensing block B 1 . In the sensor chip  100 , respective second detection beams in three T-patterned beam structures are connected to one another each at one end. In contrast to the sensor chip  100 , the sensor chip  100 C further includes a T-patterned beam structure  131 T 4  that includes a first detection beam  131   g  and a second detection beam  131   h . The T-patterned beam structure  131 T 4  is disposed such that the connection portion  141  is interposed between the T-patterned beam structure  131 T 3  and the T-patterned beam structure  131 T 4 . The structure in each of sensing blocks B 2  to B 4  is the same as that in the sensing block B 1 . 
     As described above, the T-patterned beam structure is not limited to having three beams in a given sensor chip. The T-patterned beam structure may include two beams as in the sensor chip  100 B. Alternatively, the T-patterned beam structure may include four beams as in the sensor chip  100 C. In both cases, when each sensing block includes two or more T-patterned beam structures, one or more first detection beams or one or more second detection beams included in a given T-patterned beam structure can greatly deform. With this arrangement, at least one input among the input Fx and the input Fy can be detected effectively. Further, even if one input among the input Fx and the input Fy is increased, any detection beams are not broken. That is, in any sensor chip, fracture resistance of beams with respect to displacements in various directions can be improved. Therefore, the sensor chip can be used for increased rating capacity, as well as having an increased measurement range and load bearing. 
     When two T-patterned beam structures are used, it is difficult to detect displacements in 6-axis directions. When the number of T-patterned beam structures is increased, it is advantageous in that it is easier to isolate forces of multiple axes. However, the chip size may be likely to be increased. In view of the point described above, it is preferable to use three T-patterned beam structures in order to detect displacements in the 6-axis directions. 
     &lt;Second Modification of the First Embodiment&gt; 
     A second modification of the first embodiment illustrates an example of the strain inducing body having a different structure from that in the first embodiment. In the second modification of the first embodiment, description for the same configuration that has been described in the above embodiments may be omitted. 
       FIG.  31    is a perspective view of a strain inducing body  200 A.  FIG.  32    is a cross-sectional perspective view of the strain inducing body  200 A. Referring to  FIG.  31    and  FIG.  32   , the strain inducing body  200 A includes the force receiving plate  210 , the strain inducing portion  220 , an input transmitter  230 A, and a cover plate  240 A. The strain inducing portion  220  is layered on the force receiving plate  210 , and the input transmitter  230 A is layered on the strain inducing portion  220 . The cover plate  240 A is layered on the input transmitter  230 A. With this arrangement, the strain inducing portion  200 A is formed to be substantially cylindrical as a whole. The central portion of the cover plate  240 A can be opened and closed by an inner lid portion  241 . The force receiving plate  210  and the strain inducing portion  220  are configured as in the strain inducing body  200 . 
       FIG.  33    is a perspective top view of the input transmitter included in the strain inducing body. As illustrated in  FIG.  33   , the input transmitter  230 A has the same basic structure as that of the input transmitter  230 . However, the input transmitter  230 A is formed to be thinner than the input transmitter  230 . 
       FIG.  34    is a perspective view of the cover plate included in the strain inducing body. As illustrated in  FIG.  34   , the cover plate  240 A is a member that is substantially disk-shaped as a whole and protects internal components (the sensor chip  100  and the like). For example, the cover plate  240 A is formed to be thicker than the force receiving plate  210 , the strain inducing portion  220 , and the input transmitter  230 A, and has a wide internal space toward the input transmitter  230 A. The cover plate  240 A has through-holes  248  and  249 . The through-hole  249  is closed by the inner lid portion  241  (see  FIG.  31   ). 
     As described above, a boundary between given components included in the strain inducing body can be changed in consideration of (i) an internal space provided in the strain inducting body, (ii) an assembling level, and (iii) the like. In the example illustrated in  FIGS.  31  to  34   , the boundary between the input transmitter and the cover plate is changed in comparison to the case illustrated in  FIG.  1    and the like. In this case, a wide internal space toward the cover plate  240 A can be provided and thus more components can be incorporated in the space. 
     (Third Modification of the First Embodiment) 
     A third modification of the first embodiment illustrates another example of the strain inducing body having a different structure from that described in the first embodiment. In the third modification of the first embodiment, description for the configuration that is the same as that described in the above embodiments may be omitted. 
       FIG.  35    is a side view of a strain inducing body  200 B. Referring to  FIG.  35   , the strain inducing body  200 B includes the force receiving plate  210 , a strain inducing portion  220 B, the input transmitter  230 , and the cover plate  240 . The strain inducing portion  220 B is layered on the force receiving plate  210 , the input transmitter  230  is layered on the strain inducing portion  220 B, and the cover plate  240  is layered on the input transmitter  230 . With this arrangement, the strain inducing portion  200 B is formed to be substantially cylindrical as a whole. The force receiving plate  210 , the input transmitter  230 , and the cover plate  240  are configured as in the strain inducing body  200 . 
       FIG.  36    is a perspective bottom view of the strain inducing portion included in the strain inducing body. In  FIG.  36   , the strain inducing portion  220 B is inverted up-down from  FIG.  35   . As illustrated in  FIG.  35    and  FIG.  36   , the strain inducing portion  220 B has a protrusion  225  that protrudes toward the force receiving plate  210 . The protrusion  225  is substantially circular in a plan view and is configured to be in contact with the central portion  212  of the force receiving plate  210 . A protruding amount of the protrusion  225  from the bottom surface of the strain inducing portion  220 B is, for example, about 0.5 mm. The protrusion  225  is bonded to the central portion  212  of the force receiving plate  210 , by, for example, diffusion bonding. However, fastening may be performed with screws, or welding may be performed. After the strain inducing portion  220 B and the force receiving plate  210  are bonded to each other, a space provided between the strain inducing portion  220 B and the force receiving plate  210  is defined by the height of the protrusion  225 . 
     A space needs to be provided between the strain inducing portion  220 B and the force receiving portion  210 , in order for the force receiving portion  210  to deform in response to receiving a force. By providing the protrusion  225  in the strain inducing portion  220 B, the space can be easily provided between the force receiving portion  210  and the strain inducing portion  220 B, in the strain inducing body  200 B. That is, by providing the protrusion  225  in the strain inducing portion  220 B, the height of the protrusion  225  can be adjusted, and thus the space between the strain inducing portion  220 B and the force receiving plate  210  can be adjusted. For example, if the height of the protrusion  225  is precisely adjusted by polishing or the like, prior to bonding of the strain inducing portion  220 B and the force receiving plate  210 , the space provided after the bonding can be adjusted as appropriately. Further, in a method of providing the protrusion  225  in the strain inducing portion  220 B, a narrow space, which is difficult to form by machining such as bonding or wire cutting, can be formed. When the strain inducing portion  220 B and the force receiving plate  210  are bonded by diffusion bonding, bonding strength corresponding to material strength is obtained. 
     The protrusion may be provided on the side of the force receiving plate  210 . Alternatively, protrusions may be respectively provided on both the strain inducing portion  220 B and the force receiving plate  210 . In any case, one or more protrusions are provided between the strain inducing portion  220 B and the force receiving plate  210 , and function as a space-defining portion for defining a given space between the strain inducing portion  220 B and the force receiving plate  210 . 
     Although the preferred embodiments have been described in detail above, various modifications and substitutions can be made to the embodiments described above without departing from the scope defined in the present disclosure.