JP2006214962A - Array type contact pressure sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an array type contact pressure sensor capable of detecting contact pressure with reduced crosstalk and high density, and capable of providing a deflection detecting element on a face opposite to a contact face contacting with an examined object of a semiconductor substrate. <P>SOLUTION: A plurality of pressure sensitive elements 34 arrayed unidirectionally A in the semiconductor substrate 24 of fixed thickness includes (a) a plurality of beam parts 38 in parallel each other formed between grooves 36 by providing the grooves 36 of prescribed pattern in an inner face 32 of the semiconductor substrate 24, and (b) the plurality of deflection detecting elements 42 provided in the plurality of beam parts 38, and for generating respectively electric signals in response to deflections of the beam parts 38, and (c) outputs respectively the electric signals in response to the contact pressure applied onto a pressing face 44 of the semiconductor substrate 24. The array type contact pressure sensor 26 is provided to detect a contact pressure distribution with the reduced crosstalk and the high density, and to install the deflection detecting element 42 on the inner face 32 in the side opposite to the pressing face 44 of the semiconductor substrate 24. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an array-type contact pressure sensor in which a plurality of pressure sensitive elements are arranged in one direction at a predetermined interval.

  An array-type contact pressure sensor in which a plurality of pressure-sensitive elements are arranged in one direction has been proposed for use as a tactile sensor provided at the tip of a robot or a prosthetic limb, a medical pressure pulse wave sensor, an occlusal pressure sensor, or the like. ing. For example, it is described in Patent Document 1, and a plurality of rectangular or round diaphragm portions, that is, thin-walled portions are locally provided on a semiconductor substrate, and the diaphragm is detected in order to detect bending of the diaphragm portion. A plurality of deflection detecting elements respectively provided in the section are provided. According to this, a pressure detection element is comprised from the diaphragm part and the bending detection element provided in it, and a contact pressure etc. are detected by the several pressure detection element arrange | positioned at the semiconductor substrate. However, in such a conventional array-type contact pressure sensor, it is difficult to provide diaphragm portions whose thickness is locally reduced on a semiconductor substrate at a short pitch, that is, at a high arrangement density, and the pressure detection portion becomes rough. There were drawbacks.

On the other hand, as described in Patent Document 2, a diaphragm portion whose thickness is locally thinned in a semiconductor substrate is formed into a trench shape, that is, a longitudinal shape (long groove shape), and a deflection detecting element is provided at a predetermined interval in the diaphragm portion. An array-type contact pressure sensor in which is arranged has been proposed. According to this, since the bending detection elements can be arranged on the diaphragm portion which is thin and has the same thickness, there is an advantage that the mutual arrangement interval (pitch) can be reduced and the density of the pressure detection parts can be relatively increased.
Japanese Patent No. 2999804 Japanese Patent No. 3039934

  However, when a longitudinal diaphragm portion is used as described in Patent Document 2, crosstalk occurs between adjacent deflection detection elements, and the distance between the deflection detection elements is, for example, 140 in the width dimension. There is a limit to reducing the element spacing. In addition, since the deformation in the width direction and the deformation in the longitudinal direction are applied in the bending deformation of the longitudinal diaphragm portion, there are cases where the load is not linear with respect to the load depending on the load distribution. Further, since the deflection detecting element provided in the longitudinal diaphragm portion is formed by using a semiconductor integrated circuit technology using photolithography, the element is provided in the diaphragm in the longitudinal groove or in the longitudinal groove recess. Because it is difficult, it is provided on the flat side of the semiconductor substrate, that is, the side in contact with the test object. The street sensitivity and crosstalk performance could not be obtained, which caused the individual detection sensitivity to vary.

  The present invention has been made in the background of the above circumstances, and the object is to detect a contact pressure with a small crosstalk and a high density, and to contact a deflection detecting element with a test object on a semiconductor substrate. An object of the present invention is to provide an array-type contact pressure sensor that can be provided on the opposite surface.

  In order to achieve the above object, the gist of the array-type contact pressure sensor of the invention according to claim 1 is that the array-type contact pressure having a plurality of pressure-sensitive elements arranged in one direction on a semiconductor substrate having a predetermined thickness. The plurality of pressure-sensitive elements are: (a) a plurality of parallel beam portions formed between grooves formed in a predetermined pattern on one surface of the semiconductor substrate; (b) including a plurality of deflection detecting elements respectively provided on the plurality of beam portions, each generating an electrical signal corresponding to the deflection of the beam portions, and (c) added to the other surface of the semiconductor substrate. The electrical signals corresponding to the contact pressures are respectively output.

  The gist of the invention according to claim 2 is that the beam portion of the invention according to claim 1 includes a pair of orthogonal grooves in a direction orthogonal to the one direction and one end of the pair of orthogonal grooves. It is a cantilever beam that is surrounded on three sides by a communicating groove parallel to the one direction to be communicated.

  The gist of the invention according to claim 3 is that the beam portion of the invention according to claim 1 is a doubly supported beam sandwiched between a pair of orthogonal grooves in a direction orthogonal to the one direction. Features.

  According to a fourth aspect of the present invention, there is provided a deflection detecting element according to any one of the first to third aspects, wherein impurity diffusion or ion implantation is performed on one side of the semiconductor substrate of the beam portion. It is comprised from four piezoresistors which are provided by and comprise the electric bridge, It is characterized by the above-mentioned.

  Further, the gist of the invention according to claim 5 is that, among the four piezoresistors of the invention according to claim 4, two piezoresistors are arranged along the longitudinal direction of the beam portion, The other two piezoresistors are arranged along a direction orthogonal to the longitudinal direction of the beam portion.

  The gist of the invention according to claim 6 is characterized in that the groove according to any one of claims 1 to 5 has a V-shaped cross-sectional shape.

  The gist of the invention according to claim 7 is that the groove according to any one of claims 1 to 5 has a rectangular or inverted trapezoidal cross-sectional shape. To do.

  The gist of the invention according to claim 8 is that the groove of the invention according to any one of claims 1 to 5 is formed so as to penetrate the semiconductor substrate. .

  According to the first aspect of the present invention, in the array-type contact pressure sensor having a plurality of pressure sensitive elements arranged in one direction on a semiconductor substrate having a predetermined thickness, the plurality of pressure sensitive elements are: A plurality of parallel beam portions formed between the grooves by providing grooves of a predetermined pattern on one surface of the semiconductor substrate; and (b) the beam portions respectively provided on the plurality of beam portions. A plurality of deflection detecting elements each generating an electrical signal corresponding to the deflection of the semiconductor substrate, and (c) outputting the electrical signal corresponding to the contact pressure applied to the other surface of the semiconductor substrate. Since there is no restriction on width or depression, contact pressure can be detected with low crosstalk and high density, and a deflection detecting element can be provided on the surface of the semiconductor substrate opposite to the surface in contact with the test object. Array type contact pressure sensor

  Further, according to the invention according to claim 2, the beam portion of the invention according to claim 1 communicates a pair of orthogonal grooves in a direction orthogonal to the one direction and one end of the pair of orthogonal grooves. Since it can act as a cantilever beam that is surrounded on three sides by a communication groove parallel to one direction, deformation or distortion with respect to the contact pressure (input) at the beam portion increases, and high detection sensitivity is obtained.

  Further, according to the invention according to claim 3, since the beam portion of the invention according to claim 1 can act as a doubly supported beam sandwiched between a pair of orthogonal grooves in a direction orthogonal to the one direction, the beam portion A stable contact pressure detecting operation with no variation in deflection can be obtained.

  According to a fourth aspect of the present invention, the deflection detecting element according to any one of the first to third aspects includes impurity diffusion or ion implantation (ion implantation) on one side of the semiconductor substrate of the beam portion. ) And four piezoresistors constituting an electric bridge, that is, a direct current or alternating current bridge, so that the contact pressure can be easily detected.

  According to the invention according to claim 5, of the four piezoresistors of the invention according to claim 4, two piezoresistors are disposed along the longitudinal direction of the beam portion, and the other two Since the piezoresistor is disposed along a direction orthogonal to the longitudinal direction of the beam portion, the bending or distortion generated in the beam portion when contact pressure is applied from the other surface of the semiconductor substrate is preferable. And an electric signal corresponding to the magnitude of the contact pressure is obtained.

  According to the invention of claim 6, the groove of the invention according to any one of claims 1 to 5 has a V-shaped cross-sectional shape. The arrangement interval can be reduced, and the arrangement density of the pressure detection elements can be increased.

  Further, according to the invention according to claim 7, since the groove of the invention according to any one of claims 1 to 5 has a rectangular or inverted trapezoidal cross-sectional shape, crosstalk is reduced. However, the arrangement interval of the beam portions can be reduced, and the arrangement density of the pressure detection elements can be increased. Further, compared to the V-shaped cross-sectional groove, the arrangement interval of the beam portions is increased, but high detection sensitivity can be obtained.

  According to an eighth aspect of the present invention, since the groove according to any one of the first to fifth aspects is formed so as to penetrate the semiconductor substrate, the V-shaped cross section is formed. Compared to a groove having a shape, high detection sensitivity can be obtained, and crosstalk can be almost eliminated.

  Here, preferably, the semiconductor substrate is, for example, a single crystal substrate of silicon (Si), and the impurity is, for example, boron (B).

  The deflection detecting element may be a piezoresistor that changes the resistance value according to the magnitude of strain, but a diode that changes the passing current value of the PN junction according to the magnitude of strain, A transistor that changes the current amplification factor according to the size may be used.

  In addition, the groove is provided so as to form two or three sides of the four sides of the beam portion on one surface of the semiconductor substrate to form the beam portion. May be provided with a groove having a similar pattern.

  Further, the groove may have a rectangular cross-sectional shape as well as a V shape and an inverted trapezoidal shape.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. FIG. 1 shows a small manipulator 12 having an array-type contact pressure sensor 10 that functions as a contact pressure detecting device according to an embodiment of the present invention. The small manipulator 12 includes a pair of parallel fingers 14 provided so as to be close to and away from each other, and an actuator 16 that drives the pair of fingers 14 in a direction to approach or separate from each other. Attached to the tip of the arm, for example, grasps a blood vessel 20 of a living body during surgery, a biological tissue such as skin, and holds it in a predetermined position or moves it to an appropriate position. The actuator 16 includes, for example, a screw feed mechanism that drives at least one of the pair of fingers 14 in the approaching / separating direction using the rotational force of the electric motor.

  The array-type contact pressure sensor 10 is provided inside the pair of fingers 14, that is, on at least one of the opposing surfaces of the pair of fingers 14. The control device 18 controls the gripping force, that is, the clamping force of the pair of fingers 14 based on the contact pressure of the fingers 14 detected by the array-type contact pressure sensor 10, and for example, a blood vessel of a living body during surgery with an appropriate gripping force. 20 and living tissue such as skin can be grasped. The control device 18 includes a display 22 that can display an image, and displays the contact pressure of the blood vessel 20 detected by the array-type contact pressure sensor 10 and the contact pressure distribution of the blood vessel 20.

  The array-type contact pressure sensor 10 provided on the finger 14 electrically insulates the semiconductor substrate 24 so as to be located on a clamping surface, that is, a part (center portion) of the contact surface 26 that is an opposing surface of the pair of fingers 14. A plurality of, for example, 25 to 50 pressure-sensitive elements arranged in one direction A, that is, in the longitudinal direction of the fingers 14 on the inner surface (one surface) 32 of the semiconductor substrate 24. This is an array type contact pressure sensor including an element 34. The semiconductor substrate 24 is made of a silicon single crystal plate having a thickness T of about 0.1 mm, for example. The contact surface 26 is provided with an insulating protective film 30 made of, for example, silicon resin, and the contact surface 44 of the semiconductor substrate 24 is also protected. However, the insulating protective film 30 is not necessarily provided.

  FIG. 2 shows the main part of the semiconductor substrate 24. As shown in FIG. 2, the inner surface 32 opposite to the contact surface 44 of the semiconductor substrate 24 is located at a certain interval in one direction A and is parallel to each other in a direction perpendicular to the one direction A. A comb-shaped pattern groove 36 comprising a plurality of formed orthogonal grooves 36a and a communication groove 36b formed in parallel with the one direction A and communicating one end of the orthogonal grooves 36a with each other. A plurality of cantilever-like beam portions 38 surrounded by three sides by a pair of orthogonal grooves 36a and communication grooves 36b are formed by being formed by a technique such as etching through a resist provided with a window. Has been.

  Further, as shown in detail in FIG. 3, in order to output an electric signal corresponding to the deflection of the beam portion 38, an electric power composed of four piezoresistors 40a to 40d whose resistance value is changed according to the magnitude of strain. A deflection detecting element 42 constituted by a bridge is provided on one surface side of the semiconductor substrate 24 of the beam portion 38. Each of the pressure sensitive elements 34 is composed of the beam portion 38 and the deflection detecting element 42, and the electric pressure corresponding to the magnitude of the contact pressure applied to the other surface side of the semiconductor substrate 24, that is, the outer surface side serving as the contact surface 44. Each signal is output.

The groove 36, the piezoresistors 40a to 40d, the wiring (not shown), and the like are provided by using photolithography used in integrated circuit manufacturing technology. For example, the groove 36 is formed by selective etching through the resist removed by removing a part of the resist applied to one surface of the semiconductor substrate 24 in a comb-like pattern by exposure. Moreover, the piezoresistors 40a~40d, a part of the resist applied on a surface of the semiconductor substrate 24 is removed in a predetermined resistor pattern by exposure, further SiO ₂ removal of the substrate surface in the pattern, its removal As a result of selective thermal diffusion of impurities such as boron (B) through the resist window removed by the step, a plurality of sets of piezoresistors 40a to 40d having a predetermined impurity surface concentration and resistance value are formed. Alternatively, the piezoresistors 40a to 40d can be configured by ion implantation (ion implantation) of impurities into the resistor pattern region. The piezoresistors 40a to 40d are wired to each other by a conductor film using a resist from which a conductor pattern is removed, for example, an aluminum vapor deposition film, so as to constitute an electric bridge for constituting the deflection detecting element 42. .

  In the bending detection element 42, in order to efficiently convert the bending or distortion generated in each beam portion 38 in accordance with the contact pressure applied to the pressing surface 44 into an electric signal, the bending detection element 42 is positioned at the positions of four sides of a rectangle, that is, a rectangle. Two piezoresistors 40a and 40c among the piezoresistors 40a to 40d arranged and connected in the form of a bridge are arranged along the longitudinal direction of the beam portion 38, and the other two piezoresistors 40b and 40b are connected. 40 d is arranged along a direction orthogonal to the longitudinal direction of the beam portion 38. 3 shows a state in which the piezoresistors 40a to 40d constituting the deflection detecting element 42 are provided in one beam portion 38, and are omitted in the other beam portions 38. FIG.

As shown in FIG. 4 which is a sectional view taken along line IV-IV in FIG. 3 and FIG. 5 which is a sectional view taken along line VV in FIG. 3, the groove 36 has an inverted trapezoidal sectional shape. a depth D of about .08Mm, and a groove bottom width g _w of about 0.2 mm. Therefore, the thickness of the portion of the semiconductor substrate 24 where the groove 36 is formed is, for example, about 0.02 mm, and the arrangement pitch of the pressure sensitive elements 34, that is, the beam portions 38, is about 0.4 mm.

  FIG. 6 is a diagram for explaining the electrical configuration of the array-type contact pressure sensor 10 and the control device 18. A constant bridge voltage of AC or DC is supplied from a constant voltage power source 50 to each deflection detecting element 42 provided in each beam portion 38 arranged in one direction in the semiconductor substrate 24, and from each deflection detecting element 42. The output electrical signal is input to the A / D converter 60 via the preamplifier 54 and the amplifier 58, respectively. A computer (electronic control unit) 70 including a CPU 62, a RAM 64, a ROM 66, an interface 68 and the like uses an input signal stored in the ROM 66 in advance, that is, an electric signal output from each deflection detecting element 42, using the temporary storage function of the RAM 64. The contact pressure and the surface pressure distribution of the blood vessel 20 are calculated based on the electrical signals from the respective deflection detection elements 42, and the driving circuit 72 is controlled so that the pinching pressure of the fingers 14 of the small manipulator 12 has an appropriate magnitude. For example, the blood vessel 20 can be gripped without being damaged. In addition, the computer 70 displays the contact pressure or its distribution on the display 22 based on the signal from the deflection detection element 42.

  According to the array-type contact pressure sensor 10 of the present embodiment configured as described above, the plurality of pressure-sensitive elements 34 arranged in one direction A on the inner surface (one surface) 32 of the semiconductor substrate 24 having a constant thickness are (A) a plurality of beam portions 38 formed between the grooves 36 by providing grooves 36 of a predetermined pattern on the inner surface 32 of the semiconductor substrate 24; and (b) the plurality of beams. A plurality of deflection detecting elements 42 provided on each of the portions 38 and generating respective electrical signals corresponding to the deflection of the beam portions 38, and (c) a pressing surface (other surface, outer surface) of the semiconductor substrate 24. Since the electrical signals corresponding to the contact pressure applied to 44 are respectively output, the contact pressure (distribution) can be detected with low crosstalk and high density, and the deflection detecting element 42 contacts the test object on the semiconductor substrate 24. On the opposite side of the pressing surface 44 Array contact pressure sensor 10 can be provided on the surface 32 is obtained.

  Incidentally, in a conventional array type contact pressure sensor in which a deflection detecting element is arranged at a predetermined interval on a plate-like diaphragm in order to detect the deflection of the plate-like diaphragm that generates and detects a strain for detecting the contact pressure. When the contact pressure is detected at a high density by reducing the interval between the deflection detecting elements, the width of the diaphragm must be reduced to prevent crosstalk. Therefore, in order to maintain the sensitivity of the diaphragm Since the thickness must be reduced, (a) the frequency characteristics deteriorate (resonance frequency decreases) and vibration modes become complex with the thinning, (b) the temperature characteristics deteriorate (thermal distortion, temperature drift), (c) Deterioration of structural strength, (d) Decrease in manufacturing yield of thickness distribution management, (e) Increase in sensitivity variation between deflection detection elements, (f) Deflection detection on outer surface of plate diaphragm The element is provided and wired, and since an insulating protective film is required to protect the wiring, the sensitivity and crosstalk performance as designed are not obtained, contributing to variations in individual detection sensitivity. There was a problem such as. However, according to the array-type contact pressure sensor 10 of the above-described embodiment, the arrangement interval between the beam portion 38 formed by the groove 36 and the deflection detection element 42 provided thereon without changing the diaphragm width dimension and the wall thickness ( Since the thickness of the beam portion 38 is secured and the structural strength is increased, the resonance frequency (natural frequency) is high, complicated vibration modes are suppressed, and thermal distortion is suppressed. As a result, the impurity concentration of the piezoresistors 40a to 40d is secured and the temperature drift is improved, and the variation in sensitivity between the deflection detecting elements 42 is suppressed by reducing the ratio to the thickness error, and the piezoresistors 40a to 40d are configured. Can be provided from the inner side surface of the semiconductor substrate, so that an insulating protective film is not required, thereby reducing the number of man-hours. Special effect click and sensitivity their variation obtained as designed is suppressed is obtained.

  Further, according to the array-type contact pressure sensor 10 of the present embodiment, the beam portion 38 communicates a pair of orthogonal grooves 36a in a direction orthogonal to the one direction A and one end portion of the pair of orthogonal grooves 36a. Since it can act as a cantilever beam surrounded on three sides by the communication groove 36b parallel to the direction A, deformation or distortion with respect to the contact pressure (input) at the beam portion 38 is increased, and high detection sensitivity is obtained.

  Further, according to the array-type contact pressure sensor 10 of the present embodiment, the deflection detecting element 42 provided on the beam portion 38 of the semiconductor substrate 24 diffuses impurities on the one surface 32 side of the semiconductor substrate 24 of the beam portion 38. Since it is constituted by four piezoresistors 40a to 40d which are provided by ion implantation (ion implant) and constitute an electric bridge, that is, a DC or AC bridge, it is possible to easily detect a contact pressure.

  Further, according to the array-type contact pressure sensor 10 of the present embodiment, the two piezoresistors 40 a and 40 c among the four piezoresistors 40 a to 40 d constituting the deflection detecting element 42 are arranged in the longitudinal direction of the beam portion 38. The other two piezoresistors 40b and 40d are disposed along the direction orthogonal to the longitudinal direction of the beam portion 38, and therefore contact pressure is applied from the other surface 44 of the semiconductor substrate 24. As a result, the bending or distortion generated in the beam portion 38 is suitably detected, and an electric signal corresponding to the magnitude of the contact pressure is obtained.

  Further, according to the array-type contact pressure sensor 10 of the present embodiment, the groove 36 has a rectangular or inverted trapezoidal cross-sectional shape, so that the arrangement interval of the beam portions 38 is reduced while reducing crosstalk. And the arrangement density of the deflection detecting elements 42 can be increased. In addition, the arrangement interval of the beam portions 38 is larger than that of the groove having the V-shaped cross section, but high detection sensitivity can be obtained.

  Next, another embodiment of the present invention will be described. In the following embodiments, portions common to the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 7 shows a main part of a semiconductor substrate 24 according to another embodiment of the present invention. In the semiconductor substrate 24 of the present embodiment, a plurality of orthogonal grooves 36a in a direction perpendicular to the one direction A are formed at a constant interval along the one direction A, and are sandwiched between the pair of orthogonal grooves 36a. A plurality of beam portions 80 whose portions can act as doubly supported beams are formed. Similar to the above-described embodiment, each beam 80 is provided with a deflection detecting element 42 that outputs an electric signal corresponding to the deflection of the beam 80, that is, the magnitude of distortion. In the present embodiment, the same effects as those of the above-described embodiment can be obtained, and a stable contact pressure detecting operation can be obtained in which there is no variation in deflection in each beam portion 80 that can act as a double-supported beam.

  FIG. 8 is a cross-sectional view of a semiconductor substrate 24 according to another embodiment of the present invention and corresponds to FIG. In the embodiment of FIG. 8, the orthogonal groove 36a has a V-shaped cross-sectional shape. In the semiconductor substrate 24 of this embodiment, since the orthogonal groove 36a has a V-shaped cross-sectional shape, the arrangement interval of the beam portions 38 can be reduced while reducing the crosstalk, and the arrangement density of the pressure sensitive elements 34 is increased. be able to.

  FIG. 9 is a cross-sectional view of a semiconductor substrate 24 according to another embodiment of the present invention and corresponds to FIG. In the embodiment of FIG. 9, the orthogonal groove 36 a has an inverted trapezoidal shape, but is formed through the semiconductor substrate 24. In the semiconductor substrate 24 of this embodiment, since the orthogonal groove 36a is formed so as to penetrate the semiconductor substrate 24, high detection sensitivity can be obtained as compared with the groove having the V-shaped cross section. Can almost eliminate crosstalk.

  Hereinafter, numerical examples performed by the present inventors will be described. 10, 11 and 12 show the test pieces 90, 92 and 94. FIG. The test pieces 90, 92, and 94 are formed in a longitudinal shape having a predetermined width W with the same material and thickness as those of the semiconductor substrate 24 described above, and the periphery is fixed to perform a numerical experiment. The test piece 90 does not include a groove, but the test piece 92 includes a pair of grooves 96 having a V-shaped cross section that penetrates in the width direction at a predetermined interval gw in the longitudinal direction. This groove 96 is the same as the orthogonal groove 36a in the embodiment of FIG. The test piece 94 also includes a pair of rectangular cross-sectional grooves 98 penetrating in the width direction at a predetermined interval gw in the longitudinal direction.

When the pressing force F is applied upward to the center point of the back surface of the test piece 90, distortion occurs as shown by the contour-line broken line in FIG. 10, and the distortion is the center line C in the width direction of the test piece 90. Above, the distribution represented on the lower side of the test piece 90 of FIG. 10 is shown. The distortion of the test piece 90 corresponds to that of the longitudinal diaphragm portion in which the deflection detection elements are arranged at predetermined intervals in the conventional array-type contact pressure sensor. As shown in FIG. 10, the range B of the distortion in the longitudinal direction corresponds to 1.4 times the width dimension W of the test piece 90, and in order to avoid crosstalk, the arrangement pitch of the deflection detection elements is set to the width. It was necessary to set it to be equal to or greater than 1.4 times the dimension W, and it was difficult to increase the pressure detection density. As shown in FIG. 13, when the point of action of the pressing force F is a position L ₁ that is shifted from the central position L _{0 in the} longitudinal direction by a predetermined distance, the distribution shown by the solid line centered on the central position L ₀ is shown. from it becomes distributions shown in dot-dash line around the position L ₁ offset above, Q ₁ from its the central position L ₀ deflection detection element and is provided, the magnitude of the strain to be detected Q ₀ points The detected pressure is greatly reduced. For this reason, when the displacement of the contact point of the contact pressure occurs, sufficient detection accuracy cannot be obtained.

  On the other hand, in the test piece 92 provided with the pair of grooves 96 having a V-shaped cross section shown in FIG. 11, when a pressing force F is applied upward to the center point of the back surface, it is indicated by the contoured broken line in FIG. Thus, the distortion occurs, and the distortion shows a distribution expressed on the lower side of the test piece 92 in FIG. 11 on the center line C in the width direction of the test piece 92. As shown by a broken line in FIG. 11, the range of influence of distortion in the longitudinal direction is within the region between the pair of V-shaped cross-sectional grooves 96 arranged at a gap gw set smaller than the width dimension W of the test piece 92. The influence of crosstalk does not exceed that range. For this reason, in the case of the above-described embodiment using the portion between the pair of V-shaped cross-section grooves 96 as the beam portion 38, the arrangement pitch of the deflection detection elements can be set smaller than the width dimension W, and the pressure detection density can be set. It became possible to raise it. Such an effect can be obtained in the same manner even when a groove 36 having an inverted trapezoidal section or a groove 98 having a rectangular section is used instead of the groove 96 having the V-shaped section.

Further, in the test piece 94 having the pair of rectangular cross-section grooves 98 shown in FIG. 12, the pressure distribution in the region between the pair of rectangular cross-section grooves 98 becomes relatively flat as shown in FIG. even if the acting point of the pressing force F becomes the position L ₁ displaced from the center position L ₀ by the predetermined distance, centered on the position L ₁ offset above the distribution shown by the solid line around the center position L ₀ The difference from the distribution indicated by the one-dot chain line is small. For this reason, there is almost no difference between the magnitudes Q ₀ and Q _{1 of the} strain detected by the deflection detecting element provided at the center position L ₀ , so that the deviation of the contact point of the contact pressure occurs. In addition, sufficient detection accuracy can be obtained. Therefore, in the case of the above-described embodiment in which the portion between the pair of V-shaped cross-section grooves 96 is used as the beam portion 38, sufficient detection accuracy can be obtained even if the operating point of the contact pressure shifts. Such an effect can be similarly obtained even when a groove 36 having an inverted trapezoidal cross section or a groove 96 having a V-shaped cross section is used instead of the groove 98 having the rectangular cross section.

  In order to examine crosstalk, the present inventors have a flat test piece 90 of FIG. 10 having a thickness of 0.1 mm and not provided with a groove, and a groove 96 having a V-shaped cross section. 11 test pieces 92 were subjected to analysis and calculation of strain when a load of 100 mmHg was applied, respectively, and the load range (= longitudinal dimension to which load was applied / substrate width dimension W) and normalized maximum strain (= Relative value with the maximum strain value being 1). FIG. 15 shows the relationship. As shown in FIG. 15, in the test piece 90 in which no groove is provided, the normalized maximum strain is saturated in a load range of about 1.4 times the width dimension W. Therefore, the bending detection is performed so that there is no crosstalk. If the element 42 is to be arranged, the arrangement interval must be about 1.4 times the width dimension W or more, and it can be seen that it is difficult to increase the pressure detection density. On the other hand, in the test piece 92 provided with the groove 96 having a V-shaped cross section, the normalized maximum strain is saturated in a load range equal to or less than one time of the width dimension W. Therefore, even at an interval equal to or less than one time of the width dimension W. The deflection detecting element 42 can be arranged so as not to cause crosstalk, and a high pressure detection density can be obtained. The broken line in FIG. 15 indicates a 10% crosstalk line, and the 10% crosstalk width described later is the value of the load range when the normalized maximum distortion reaches the 10% crosstalk line.

  In order to examine the thickness of the semiconductor substrate 24, the inventors have four types of thicknesses (0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm) and are not formed with a groove. Using the test piece 90 of FIG. 10, the relationship between the thickness and the maximum strain when a load of 100 mmHg was applied to a load width of 1 mm (= longitudinal dimension to which a load is applied) was determined. FIG. 16 shows the relationship. In addition, the inventors analyzed and calculated the strain when a load of 100 mmHg was applied using the four types of test pieces 90 having different thicknesses, and found the relationship between the load range and the normalized maximum strain. It was. FIG. 17 shows the relationship. As apparent from the curve of FIG. 17, the relationship between the load range and the normalized maximum strain hardly changes with respect to the change in thickness. However, as is clear from FIG. It can be seen that distortion increases and detection sensitivity increases. Regarding the detection sensitivity, a thickness of 0.2 mm or less, more preferably 0.1 mm or less is desirable. However, when the thickness falls below 0.05 mm, the frequency characteristic is deteriorated (decreased) due to a decrease in rigidity, and the vibration mode is decreased. Inconveniences such as complications in strength, deterioration in strength, deterioration in temperature characteristics, and difficulty in managing the thickness distribution occur.

In order to examine the relationship between the groove bottom dimension g _W and the detection sensitivity, the present inventors have five types of groove widths (the groove bottom dimension g _W is 0 mm, 0.1 mm, 0.2 mm, 0.3 mm). 0.4 mm) using a test piece having a cantilever beam 38 shown in FIGS. 2 to 5 and a test piece having a cantilever beam 80 shown in FIG. , Analyze and calculate the maximum strain when a load of 100 mmHg is applied to these beams, and show the relationship between the groove bottom width g _W and the maximum strain, the cantilever beam 38 and the doubly supported beam Part 80 was obtained. FIG. 18 shows the relationship. As shown in FIG. 18, the maximum strain, that is, the sensitivity increases as the groove bottom width g _W increases, and the maximum strain, that is, the sensitivity of the cantilever-shaped beam portion 38 is higher than that of the double-supported beam-shaped beam portion 80. Is big. Incidentally, the groove bottom width g _W is A 0mm groove shows a groove of V-shaped cross section.

In order to examine the relationship between the groove width dimension and crosstalk, the present inventors have five kinds of groove widths (the groove bottom width dimension g _W is 0 mm, 0.1 mm, 0.2 mm, 0.3 mm,. 4 mm) using a test piece having a cantilever beam portion 38 shown in FIGS. 2 to 5 and a test piece having a cantilever beam portion 80 shown in FIG. the load was analyzed and calculated the maximum strain when added to their beam portion, and the relationship between the load range and the normalized maximum strain, the relationship between the groove bottom width g _W and 10% crosstalk width (mm) Were obtained for the cantilever beam 38 and the cantilever beam 80, respectively. FIG. 19 shows the relationship between the load range and the normalized maximum strain in the test piece including the cantilever beam 80, and the relationship between the groove bottom width g _W and the 10% crosstalk width (mm) is shown in FIG. It is shown in FIG. FIG. 21 shows the relationship between the load range and the normalized maximum strain in the cantilever beam portion 38, and FIG. 22 shows the relationship between the groove bottom width dimension g _W and the 10% crosstalk width (mm). It is shown.

As shown in the curves of FIG. 19 and FIG. 21 above, in relation to the load range and the normalized maximum strain, the groove bottom width in each of the cantilever beam portion 38 and the cantilever beam portion 80 is shown. It hardly changes for the change of the dimension g _W. However, the relationship between the groove bottom width g _W and 10% crosstalk width (mm), the doubly supported beam shaped beam portion 80, as is apparent from the curve of FIG. 20, the groove bottom width g _W 0 .3 mm or less, preferably 0 to 0.25 mm, more preferably 0.1 mm to 0.2 mm, and the 10% crosstalk width is minimized. Further, as can be seen from the curve in FIG. 22, in the cantilever-shaped beam portion 38, 0.3% or less, preferably 0 mm to 0.2 mm, more preferably 0 mm to 0.1 mm, 10%. The crosstalk width is minimized.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention can be applied also in another aspect.

  For example, the thicknesses, lengths, and widths of the beam portions 30 and 80 in the above-described embodiments can be appropriately changed as necessary by changing the detection pressure range, the thickness and material of the semiconductor substrate 24, and the like.

  Further, the beam portions 30 and 80 in the above-described embodiment do not necessarily have the same thickness as the semiconductor substrate 24.

In the above-described embodiment, the actuator 16 for driving the fingers 14 provided inside the array-type contact pressure sensor 10 in the direction of approaching each other is a cylinder that uses air pressure or hydraulic pressure as driving energy. Other actuators may be used.

The array-type contact pressure sensor 10 of the above-described embodiment has been used to detect contact pressure when a pair of fingers 14 grips a blood vessel 20 during surgery. It may be used to detect a pressure pulse wave generated from an artery, brachial artery or the like.

  In the above-described embodiment, when the blood vessel 20 is grasped by the pair of fingers 14, the technique described in, for example, USP 4,269,193 is used from the contact pressure distribution detected by the array-type contact pressure sensor 10. Thus, the internal pressure of the blood vessel 20 can be measured. In this case, there is no need to insert an intra-arterial catheter as in the direct method, so that problems such as blood coagulation are avoided and it is safe. Further, a tumor or the like can be grasped by the pair of fingers 14. In this case, it is possible to make a diagnosis by measuring the relationship between the force applied to the tissue and the distribution of the degree of deformation of the tissue. At this time, by providing the array-type contact pressure sensors 10 on both fingers 14, it is possible to compare the contact pressures at two locations, so that more accurate diagnosis is possible than when only one side is provided.

  The array-type contact pressure sensor 10 of the above-described embodiment may be used as an occlusal pressure sensor, a tactile sensor provided in a robot or a prosthetic limb, in order to detect a contact pressure distribution with high resolution.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which illustrates roughly the structure of the contact pressure detection apparatus provided with the array type contact pressure sensor of one Example of this invention, and the mounting state to a biological body. FIG. 2 is a plan view in which a part of the inner side surface of the semiconductor substrate is enlarged to explain a main part of the semiconductor substrate provided in the array type pulse wave sensor of the embodiment of FIG. 1. FIG. 3 is an enlarged view for explaining a beam portion and a groove in the plan view of the semiconductor substrate of FIG. 2. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a sectional view taken along line VV in FIG. 3. It is a circuit diagram explaining the electrical structure of the contact pressure detection apparatus of FIG. It is a figure which shows the beam part of the doubly-supported beam provided in the semiconductor substrate of the other Example of this invention, Comprising: It is a figure equivalent to FIG. It is sectional drawing which shows the groove | channel provided with the V-shaped cross section provided in the semiconductor substrate of the other Example of this invention, Comprising: It is a figure equivalent to FIG. It is sectional drawing which shows the groove | channel provided with the inverted trapezoid cross section provided in the semiconductor substrate of the other Example of this invention, and penetrated the semiconductor substrate, Comprising: It is a figure equivalent to FIG. FIG. 6 is a perspective view showing a groove-less test piece of a semiconductor substrate used by the inventors for the experiment, and an upward pressing force F is applied to the center position L ₀ in the longitudinal direction on the center line C in the width direction. The magnitude and range of the distortion generated at the time of occurrence are indicated by contour-like broken lines and distribution curves. FIG. 7 is a perspective view showing a V-shaped cross-sectional grooved test piece of a semiconductor substrate used by the inventors for the experiment, and is an upward pressing force on the center line C in the longitudinal direction and in the longitudinal center position L _0. The magnitude and range of distortion that occurs when F is applied are indicated by contour-like broken lines and distribution curves. It is a perspective view which shows the test piece with a rectangular cross-sectional groove | channel of the semiconductor substrate which the present inventors used for experiment. When the point of action of the pressing force F on the grooveless test piece in FIG. 10 is shifted from the longitudinal position L ₀ to L ₁ , the magnitude of the distortion detected by the deflection detecting element provided at the longitudinal position L ₀ is as follows. from Q ₀ is a diagram for explaining the large change state to Q _1. When the point of action of the pressing force F on the rectangular cross-section grooved test piece in FIG. 12 is shifted from the longitudinal position L ₀ to L ₁ , the distortion detected by the deflection detecting element provided at the longitudinal position L ₀ is detected. the size is a diagram for explaining a state that does not substantially change from Q ₀ to Q _1. It is a figure which shows the relationship between the load range analyzed and calculated about the test piece of FIG. 10, and the test piece with a V-shaped cross-sectional groove | channel of FIG. It is a figure which shows the relationship between plate | board thickness and the largest distortion which applied the load of 100 mmHg to the load width of 1 mm and analyzed and calculated using the test piece of FIG. It is a figure which shows the relationship between the load range and normalized maximum distortion which were analyzed and calculated using the test piece of FIG. 10 from which thickness differs. 2 shows the relationship between the groove width and maximum strain, analyzed and calculated using test pieces with different groove widths, for the cantilever beam portion shown in FIG. 2 and the cantilever beam portion shown in FIG. FIG. It is a figure which shows the relationship between the load range and normalized maximum distortion which were analyzed and calculated using the test piece from which five types of groove widths which have the beam part of a cantilever beam shown in FIG. It is a figure which shows the relationship between a groove width and a 10% crosstalk width | variety analyzed and calculated using the test piece from which five types of groove widths which have the beam part of a cantilever beam shown in FIG. It is a figure which shows the relationship between the load range and normalized maximum distortion which were analyzed and calculated using the test piece from which five types of groove widths which have the beam part of a cantilever form shown in FIG. 2 differ. It is a figure which shows the relationship between a groove width and 10% crosstalk width | variety analyzed and calculated using the test piece from which five types of groove widths which have the beam part of a cantilever beam shown in FIG.

Explanation of symbols

10: Array type contact pressure sensor 24: Semiconductor substrate 34: Pressure sensitive element 36: Groove 38: Beam part 42: Deflection detecting element

Claims (8)

An array-type contact pressure sensor having a plurality of pressure-sensitive elements arranged in one direction on a semiconductor substrate having a predetermined thickness,
The plurality of pressure sensitive elements are:
A plurality of parallel beam portions formed between the grooves by providing grooves of a predetermined pattern on one surface of the semiconductor substrate;
A plurality of deflection detecting elements respectively provided on the plurality of beam portions, each of which generates an electrical signal corresponding to the deflection of the beam portions;
An array-type contact pressure sensor that outputs the electrical signals corresponding to the contact pressure applied to the other surface of the semiconductor substrate. The beam portion is a cantilever beam that is surrounded on three sides by a pair of orthogonal grooves in a direction orthogonal to the one direction and a communication groove parallel to the one direction that communicates one end of the pair of orthogonal grooves. The array-type contact pressure sensor according to claim 1. The array-type contact pressure sensor according to claim 1, wherein the beam portion is a doubly supported beam sandwiched between a pair of orthogonal grooves in a direction orthogonal to the one direction. 4. The deflection sensor according to any one of claims 1 to 3, wherein the deflection detecting element is formed of four piezoresistors that are provided on one surface side of the semiconductor substrate of the beam portion by impurity diffusion or ion implantation and constitute an electric bridge. Array type contact pressure sensor. Of the four piezoresistors, two piezoresistors are disposed along the longitudinal direction of the beam portion, and the other two piezoresistors are disposed along a direction orthogonal to the longitudinal direction of the beam portion. The array-type contact pressure sensor according to claim 4, which is provided. The array-type contact pressure sensor according to claim 1, wherein the groove has a V-shaped cross-sectional shape. The array-type contact pressure sensor according to claim 1, wherein the groove has a rectangular or inverted trapezoidal cross-sectional shape. 6. The array-type contact pressure sensor according to claim 1, wherein the groove is formed so as to penetrate the semiconductor substrate.

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