JP6488251B2 - Object sensor - Google Patents

Description

  The present invention relates to an object sensor, and more particularly to an object sensor suitable for detecting the position of an object existing in the vicinity in a non-contact state.

  Conventionally, various types of object sensors have been used as object sensors for detecting objects existing in the vicinity. Many of them are of a type that irradiates an object with light waves, radio waves, sound waves, etc., and measures the reflected waves that return. On the other hand, an object sensor using a capacitive element or a resistance element has been proposed as a sensor for detecting an object located in the immediate vicinity. Further, by arranging a large number of detection elements two-dimensionally, An object sensor that can detect the position of the object with high accuracy has also been proposed.

  For example, Patent Document 1 below discloses an object sensor that uses a capacitive element formed of a pair of electrodes in order to prevent a hand or a finger from being caught in a vehicle door. Further, Patent Document 2 proposes an object sensor that can detect the position of an object with high accuracy by two-dimensionally arranging a large number of resistance elements and is suitable for use as a tactile sensor for a robot. Yes. Further, in Patent Document 3, a large number of row-direction electrodes and a large number of column-direction electrodes are arranged on a substrate so as to cross three-dimensionally via an interlayer insulating film, and the capacitance value at the intersection is changed. A touch panel that detects the contact position of an object based on the above is disclosed, and Patent Document 4 detects the position of an object in a non-contact state by two-dimensionally arranging a large number of microsensor elements, An object sensor that can be used as a non-contact type touch panel is disclosed.

JP 2005-227244 A JP2015-114308A JP, 2014-010671, A JP 2011-221977 A

  Since the object sensor disclosed in Patent Document 1 described above is for preventing the vehicle from being caught in the door, it is sufficient if it can be determined whether there is an object in the vicinity. However, an object sensor used by being mounted on a robot arm or the like is desired to have a function of detecting not only the presence or absence of an object existing in the vicinity but also in which area the object is present. In the object sensor disclosed in Patent Document 2 described above, since a large number of resistance elements are provided, it is possible to detect which position the object is in contact with. However, since this sensor is a tactile sensor for detecting contact only, its presence cannot be detected until an object actually contacts. Similarly, the touch panel disclosed in Patent Document 3 is also a tactile sensor for detecting a position where a touch is performed with a finger or the like.

  In the future, robots are expected to be widely used in all fields of human society, and safety measures will be important to avoid situations where robots come into contact with people and cause harm. In the tactile sensors disclosed in Patent Documents 2 and 3 described above, it is difficult to take sufficient safety measures because a detection signal cannot be obtained until the robot arm contacts a person. An object sensor used for a robot is desired to have a function that can detect an object approaching a certain degree of proximity with sufficient sensitivity before contact and predict a danger.

  On the other hand, in the object sensor disclosed in Patent Document 4 described above, an object can be detected in a non-contact state by detecting a change in an electric field or a magnetic field with a large number of microsensor elements. However, the structure of each microsensor element becomes complicated, and an increase in cost is inevitable. In addition, since this object sensor is an apparatus premised on use for a touch panel, it is only necessary to arrange individual detection elements on a plane. Therefore, no problem occurs even if each detection element has a complicated structure. However, in the case of an object sensor mounted on a robot or the like, the sensor mounting surface is not necessarily a flat surface or a simple cylindrical surface. For example, in the case of an object sensor attached to the fingertip of a robot, a structure that can be mounted on a three-dimensional free-form surface is required.

  Accordingly, an object of the present invention is to provide an object sensor that can detect the position of an object located in the vicinity with sufficient sensitivity even in a non-contact state while having a simple structure.

(1) A first aspect of the present invention is an object sensor for detecting the position of an object existing in the vicinity.
A support that supports a predetermined detection surface;
A total of N sets of capacitive elements respectively disposed in the vicinity of a plurality of N detection points defined on the detection surface;
Position detecting means for detecting the position of the object based on the capacitance values of the N sets of capacitive elements;
Provided,
Each of the capacitive elements has a central electrode disposed at the detection point and a peripheral electrode disposed so as to surround the central electrode, and the central electrode and the peripheral electrode are supported by the support. ,
The position detection means specifies the position of the object based on each capacitance value measured by the capacitance value measurement unit that measures the capacitance value between the central electrode and the surrounding electrode for each capacitance element. And a position specifying unit.

(2) According to a second aspect of the present invention, in the object sensor according to the first aspect described above,
N detection points are defined side by side on a predetermined arrangement axis on the detection surface, and N sets of capacitive elements constitute a one-dimensional array along the arrangement axis,
The position specifying unit specifies a position in a one-dimensional direction along the arrangement axis for the object.

(3) According to a third aspect of the present invention, in the object sensor according to the first aspect described above,
Detection points are defined at the positions of each grid point of the two-dimensional grid placed on the detection surface,
N sets of capacitive elements constitute a two-dimensional array corresponding to the two-dimensional lattice,
The position specifying unit specifies the position in the two-dimensional direction corresponding to the two-dimensional lattice for the object.

(4) According to a fourth aspect of the present invention, in the object sensor according to the third aspect described above,
The position specifying unit determines that a capacitive element having a capacitance value equal to or greater than a predetermined threshold Ct is a significant element, and recognizes a region on the detection surface including a detection point where the significant element is disposed as a significant region. The position of the significant region on the detection surface is output as the position of the object on the two-dimensional plane.

(5) According to a fifth aspect of the present invention, in the object sensor according to the fourth aspect described above,
The position specifying unit outputs the value of the area of the significant region as information indicating the height of the specific object from the detection surface.

(6) According to a sixth aspect of the present invention, in the object sensor according to the fourth aspect described above,
The position specifying unit outputs the value of the area of the significant region as information indicating the size of the object existing at a specific height position from the detection surface.

(7) According to a seventh aspect of the present invention, in the object sensor according to the third to sixth aspects described above,
On the detection surface included in the XY plane in the XYZ three-dimensional orthogonal coordinate system, I horizontal grid lines parallel to the X axis and J vertical grid lines parallel to the Y axis are defined. A total of N lattice points are defined as a matrix of I rows and J columns at each intersection position of
J peripheral electrodes arranged along the same horizontal grid line are connected to each other by a horizontal wiring layer along the horizontal grid line, and I pieces arranged along the same vertical grid line. These central electrodes are connected to each other by a vertical wiring layer along the vertical grid lines.

(8) An eighth aspect of the present invention is the object sensor according to the seventh aspect described above,
The capacitance value measurement unit
A selector switch for selecting an i-th (1 ≦ i ≦ I) horizontal wiring layer and a j-th (1 ≦ j ≦ J) vertical wiring layer;
Capacitance arranged at the detection point located in the i-th row and j-th column by measuring the capacitance value between the selected i-th lateral wiring layer and j-th vertical wiring layer A measurement circuit for determining the capacitance value of the element;
The capacitance value of the capacitive element arranged at an arbitrary detection point is obtained by switching the selection target with the changeover switch.

(9) According to a ninth aspect of the present invention, in the object sensor according to the first to eighth aspects described above,
A first insulating layer is formed on the upper surface of the support, a second insulating layer is formed on the upper surface of the first insulating layer, and one of the first insulating layer and the second insulating layer is When we call the main insulation layer and the other is the sub insulation layer,
A central electrode, a peripheral electrode, and a peripheral electrode wiring layer for electrically connecting the peripheral electrode to the capacitance measuring unit are embedded in the main insulating layer,
A central electrode wiring layer for electrically connecting the central electrode to the capacitance measuring unit is embedded in the sub-insulating layer,
An interlayer wiring layer penetrating the boundary surface between the main insulating layer and the sub insulating layer is formed between the central electrode and the central electrode wiring layer.

(10) According to a tenth aspect of the present invention, in the object sensor according to the first to eighth aspects described above,
A first insulating layer is formed on the upper surface of the support, a second insulating layer is formed on the upper surface of the first insulating layer, and one of the first insulating layer and the second insulating layer is When the central electrode forming layer is called the surrounding electrode forming layer,
A central electrode and a central electrode wiring layer for electrically connecting the central electrode to the capacitance value measuring unit are embedded in the central electrode forming layer,
The surrounding electrode and the surrounding electrode wiring layer for electrically connecting the surrounding electrode to the capacitance value measuring unit are embedded in the surrounding electrode forming layer.

(11) According to an eleventh aspect of the present invention, in the object sensor according to the first to tenth aspects described above,
The central electrode is a disc-shaped electrode arranged around the detection point, and the surrounding electrode is an annular electrode arranged so as to surround the central electrode.

(12) According to a twelfth aspect of the present invention, in the object sensor according to the first to tenth aspects described above,
The center electrode is a disc-shaped electrode arranged around the detection point, and the peripheral electrode is arranged so as to surround the center electrode, and is an incomplete annular electrode having a notch in part. It is a thing.

(13) According to a thirteenth aspect of the present invention, in the object sensor according to the first to twelfth aspects described above,
The support is composed of a flat structure, and an opening that penetrates the thickness of the structure is provided in a region of the structure where no capacitive element is formed, so that the entire structure is deformed. It is configured.

(14) According to a fourteenth aspect of the present invention, in the object sensor according to the first to thirteenth aspects described above,
Each electrode is formed directly on the upper surface of the support or indirectly through another insulating layer, and further, the upper surface of each electrode is covered with the insulating layer.

  In the object sensor of the present invention, the position of the object can be detected based on the capacitance values of the plurality of capacitive elements arranged on the detection surface. Moreover, each capacitive element is composed of a central electrode and surrounding electrodes surrounding it, and a significant change occurs in the capacitance value just by approaching the object, so the position of the object located in the vicinity is Even a non-contact state can be detected with sufficient sensitivity.

It is a perspective view which shows the external appearance of the conventional general object sensor which detects the position of a target object. It is a top view which shows arrangement | positioning of the row direction electrode and column direction electrode which are provided in the object sensor shown in FIG. FIG. 6 is a plan view comparing the structure of the capacitor element of the conventional object sensor (FIG. (A)) and the structure of the capacitor element of the object sensor according to the present invention (FIG. (B)) (hatching is the planar shape of the electrode portion) For the sake of clarity, not a cross section). It is a top view which shows the structure of the object sensor which concerns on basic embodiment of this invention (hatching is for showing the planar shape of an electrode part clearly, and does not show a cross section). Top view showing the electrode configuration of the capacitive element used in the conventional object sensor (Figure (a): The hatching is for clearly showing the planar shape of the electrode part, not the cross section) and It is a sectional side view (figure (b)). The top view which shows the electrode structure of the capacitive element used for the object sensor which concerns on this invention (FIG. (A): The hatching is for showing the planar shape of an electrode part clearly, and does not show a cross section. ) And a side sectional view (FIG. (B)). FIG. 7 is a perspective view showing a state in which an object M passes above the capacitive element shown in FIG. 6. FIG. 7 is a side cross-sectional view illustrating a state in which an object M passes above the capacitive element illustrated in FIG. 6. It is a graph which shows the change of the electrostatic capacitance value of the capacitive element in the passage state shown in FIG. It is a 1st sectional side view which shows the generation | occurrence | production principle of the electrostatic capacitance of the capacitive element in the passage state shown in FIG. It is a 2nd sectional side view which shows the generation principle of the electrostatic capacitance of the capacitive element in the passage state shown in FIG. It is the top view which arranged three sets of capacitive elements, and a graph which shows the change of the capacitance value of each capacitive element when the target object M passes above (hatching shows clearly the plane shape of an electrode part) And not a cross section). In the object sensor according to the present invention, it is a distribution diagram of capacitance values of the capacitive elements arranged in 9 rows and 9 columns. In the object sensor which concerns on this invention, it is a three-dimensional graph which shows the method of pinpointing the position of a target object based on distribution of the electrostatic capacitance value of each capacitive element. It is a figure which shows the 1st example which specified the position of the target object based on the distribution map shown in FIG. It is a figure which shows the 2nd example which specified the position of the target object based on the distribution map shown in FIG. FIG. 4 is a top view (FIG. (A)) of an example in which wiring is applied to the basic embodiment shown in FIG. 4 and a side sectional view (FIG. (B)) showing a state where this is cut at the position of the cutting line 17b-17b. is there. The hatching in the top view (a) is for clearly showing the electrode shape, not for showing the cross section. FIG. 18 is a circuit diagram (partially a block diagram) showing an example of position detecting means 50 used in the embodiment shown in FIG. It is a table | surface which shows the switching operation | movement at the time of measuring each electrostatic capacitance value using the circuit shown in FIG. They are a top view (FIG. (A)) which shows the device of the wiring at the time of implementing the Example which makes an electrode a two-layer structure, and a side sectional view (FIG. (B)) which cut | disconnected this by the XZ plane. The hatching in the top view (a) is for clearly showing the electrode shape, not for showing the cross section. FIG. 21 is a side sectional view showing an example in which the layer configuration shown in FIG. 4 is a top view (FIG. (A)) of an example in which the device of the wiring shown in FIG. 20 is applied to the basic embodiment shown in FIG. 4, and a side sectional view showing the state cut at the cutting line 22b-22b. (Figure (b)). The hatching in the top view (a) is for clearly showing the electrode shape, not for showing the cross section. 22 is a top view (FIG. (A)) showing a modification in which an opening is formed in the embodiment shown in FIG. 22 and a side sectional view (FIG. (B)) showing a state in which the opening is cut at the position of the cutting line 23b-23b. is there. The hatching in the top view (a) is for clearly showing the electrode shape, not for showing the cross section. It is a top view which shows the variation of the center electrode and surrounding electrode which are used for this invention. Hatching is for clearly showing the electrode shape, not for showing a cross section. It is a top view which shows the modification which performs the wiring with respect to a center electrode using the notch formed in the surrounding electrode. Hatching is for clearly showing the electrode shape, not for showing a cross section.

  Hereinafter, the present invention will be described based on the illustrated embodiments.

<<< §1. Features of the capacitive element used in the present invention >>>
FIG. 1 is a perspective view showing the appearance of a conventional general object sensor that detects the position of an object. In the case of the object sensor shown here, the upper surface of the rectangular plate-like support 10 forms the detection surface S, and the object M existing in the vicinity thereof has a two-dimensional position on the detection surface S ( In the case of the illustrated example, it has a function of detecting the position of the detection point P on the detection surface S).

  In the case of an object sensor for a smartphone or tablet, a plate-like support 10 made of a transparent substrate is used, and the support 10 can be made to function as a touch panel by being placed on a display screen. In this case, the user's finger or touch pen is detected as the object M, and the user's input operation on the detection point P can be detected. In the capacitive touch panel, a large number of capacitive elements are arranged on the detection surface S, and the position of the object M is detected by measuring the change in the capacitance value of each capacitive element.

  FIG. 2 is a top view showing the configuration of the capacitive element of the touch panel disclosed in the above-mentioned Patent Document 3 and the like. As shown in the figure, in the case of this touch panel, a large number of row direction electrodes Ex1, Ex2, Ex3,..., A large number of column direction electrodes and Ey1, Ey2, Ey3,. .. are provided. Moreover, they are arranged so as to cross three-dimensionally via an interlayer insulating film. In the case of the illustrated example, column direction electrodes Ey1, Ey2, Ey3,... Are arranged on the upper surface (detection surface S) of the support 10, and the row direction electrodes Ex1, Ex2, Ex3 are disposed thereabove via an interlayer insulating film. , ... are arranged.

  Accordingly, a localized capacitance element is formed by a part of the row direction electrode and a part of the column direction electrode at the three-dimensional intersection. In the case of the illustrated example, nine row direction electrodes Ex1 to Ex9 and nine column direction electrodes Ey1 to Ey9 form intersections at a total of 81 locations, and 81 sets of localized capacitance elements are formed. . The capacitance value of each of these localized capacitance elements can be individually measured as a capacitance value between a specific column direction electrode and a specific row direction electrode.

  For example, in the top view of FIG. 2, when the detection point Pij is defined at the center of the intersection of the i-th row direction electrode Exi and the j-th column direction electrode Eyj, the detection point Pij is located near the detection point Pij. A localized capacitance element Cij is formed. When the electrostatic capacitance value of the localized capacitance element Cij is represented by the same symbol Cij, as shown in the drawing, the static capacitance between the terminal T1 connected to the column direction electrode Eyj and the terminal T2 connected to the row direction electrode Exi is shown. The capacitance value Cij of the localized capacitance element Cij can be measured as the capacitance value.

  In this way, when a plurality of row-direction electrodes composed of elongated linear electrodes and a plurality of column-direction electrodes are combined, a localized capacitance element can be formed at the intersection, so that the structure is simple. However, a large number of local capacitive elements can be two-dimensionally arranged on the detection surface S with high density. For this reason, the position of the object M can be detected with high resolution. Therefore, the conventional object sensor having the structure shown in FIG. 2 is very suitable for use as a touch panel for smartphones and tablets. That is, if linear electrodes made of fine lines are arranged at high density in the vertical and horizontal directions, the two-dimensional distribution density of the detection points Pij can be increased, and the position designated by the user on the detection surface S can be accurately grasped. .

  However, the conventional object sensor shown in FIG. 2 is not very suitable for use in detecting the position of the object M in a non-contact state. FIG. 1 shows an example in which the object M exists at a position slightly away from the detection point P on the detection surface S. In this way, even when the object M is in a non-contact state with respect to the object sensor, theoretically, the capacitance value of the localized capacitance element arranged at the detection point P changes. It is possible to detect this. However, in practice, the object M that is in a non-contact state with respect to the object sensor has a small influence on the capacitance value of the local capacitive element as shown in FIG. 2, and has sufficient sensitivity in practical use. Detection is difficult.

  Of course, in a general application as a touch panel for smartphones and tablets, the user designates the position by bringing the object M (finger or touch pen) into contact with the surface of the touch panel, so that the detection sensitivity in a non-contact state is high. Even if it is low, no problem occurs. However, as described above, in the case of an object sensor attached to a robot or the like, in order to ensure safety, a function capable of detecting an object approaching a certain degree of proximity with sufficient sensitivity before contact and predicting danger is desired. ing. From such a viewpoint, it is not preferable to use an object sensor having a structure as shown in FIG.

  The present invention has been made to solve such a problem, and has a simple structure, but can detect the position of an object located in the vicinity with sufficient sensitivity even in a non-contact state. An object is to provide a sensor.

  The feature of the present invention lies in the unique structure of the capacitive element disposed on the detection surface S. FIG. 3 is a plan view comparing the structure (FIG. (A)) of the conventional capacitive element of the object sensor illustrated in FIG. 2 and the structure (FIG. (B)) of the capacitive element of the object sensor according to the present invention. . In addition, the hatching in FIG. 3 is for showing the planar shape of an electrode part clearly, and does not show a cross section. Further, in FIG. 3, for convenience of explanation, only the vicinity region (here, referred to as a detection region A) of one set of capacitive elements is illustrated. However, in an actual object sensor, such a region is arranged on the detection surface S. A plurality of detection areas A are arranged adjacent to each other.

  FIG. 3A corresponds to an enlarged plan view in which the intersecting portion of the linear electrodes in the object sensor shown in FIG. 2 is enlarged, and the intersecting portion of one row direction electrode Ex and one column direction electrode Ey is shown. It is shown. As described above, the row direction electrode Ex is disposed above the column direction electrode Ey via the interlayer insulating film. When the detection point P is defined at the center of the solid intersection of the electrodes Ex and Ey, a set of capacitive elements is formed in the vicinity of the detection point P.

  On the other hand, FIG. 3 (b) is a plan view showing a set of capacitive elements used in the object sensor according to the present invention. Similar to FIG. 3 (a), a detection point P is defined in the detection area A, and a set of capacitive elements are arranged in the vicinity thereof, but their structures are greatly different. That is, the capacitive element used in the present invention has a central electrode Ec disposed at the detection point P and a peripheral electrode Ep disposed so as to surround the central electrode Ec. More specifically, in the case of the illustrated example, the center electrode Ec is configured by a disk-shaped electrode disposed around the detection point P, and the peripheral electrode Ep is disposed so as to surround the center electrode Ec. An annular (washer-like) electrode is used.

  FIG. 4 is a top view showing the configuration of the object sensor according to the basic embodiment of the present invention, in which nine sets of the capacitive elements shown in FIG. 3B are arranged on the support 20. In the case of this example, the square plate-like support 20 is divided into three equal parts vertically and horizontally, and nine sets of detection areas A1 to A9 arranged in three rows and three columns on the upper surface (broken lines are each Indicating the boundary of the region). A capacitive element shown in FIG. 3B is arranged in each of the nine sets of detection areas A1 to A9. In FIG. 4 as well, hatching is for clearly showing the planar shape of the electrode portion, and does not show a cross section.

  As shown in the figure, detection points P1 to P9 are defined at the centers of the detection areas A1 to A9, respectively, and the disk-shaped center electrodes Ec1 to Ec9 are arranged around the detection points P1 to P9. To surround it, annular (washer-like) peripheral electrodes Ep1 to Ep9 are arranged.

  FIG. 5A is a top view showing the electrode configuration of the conventional capacitive element of the type shown in FIG. 3A, and shows a set of capacitive elements formed on one detection region A. FIG. . Here, for convenience, an XYZ three-dimensional orthogonal coordinate system with the detection point P as the origin is defined. The right direction in the figure is the X axis, the upper direction in the figure is the Y axis, and the vertical direction in the drawing is the Z axis. is there. A column-direction electrode Ey extending in the Y-axis direction is disposed on the upper surface of the plate-like support 10 having a square shape, and a row-direction electrode Ex extending in the X-axis direction is disposed above the column-direction electrode Ey. Also in FIG. 5 (a), the hatching is for clearly showing the planar shape of the electrode portion, and does not show a cross section.

  FIG. 5 (b) is a side sectional view of the structure shown in FIG. 5 (a) cut along the XZ plane, and its layer structure is clearly shown. In the illustrated example, the coordinate system is defined such that the upper surface of the plate-like support 10 is a surface included in the XY plane, and the detection point P is the origin of this coordinate system. Here, if the upper surface (XY plane) of the plate-like support 10 is referred to as a detection surface S, the column direction electrode Ey is disposed on the detection surface S as shown in FIG. On the other hand, since the row direction electrode Ex must be three-dimensionally crossed with the column direction electrode Ey, in the illustrated example, the first insulating layer 11 is formed so as to cover the column direction electrode Ey, and the upper surface thereof is formed in the row direction. The electrode Ex is formed, and the second insulating layer 12 is formed so as to cover the electrode Ex.

  If such a configuration is adopted, in the overlapping region (a square region in FIG. 5A) in the vicinity of the detection point P, a part of the row direction electrode Ex and a part of the column direction electrode Ey face each other. A capacitive element is configured. Therefore, when the capacitance value between the row direction electrode Ex and the column direction electrode Ey is electrically measured, the measurement value is greatly influenced by the capacitance value of the localized capacitance element. When the object M such as a finger or a touch pen comes into contact with the surface of the second insulating layer 12, a significant change occurs in the measurement value.

  On the other hand, FIG. 6 (a) is a top view showing the electrode configuration of the capacitive element of the type shown in FIG. 3 (b), which is also a set of capacitive elements formed on one detection region A. FIG. It is shown. Also here, for convenience, an XYZ three-dimensional coordinate system with the detection point P as the origin is defined, the right direction in the figure is the X axis, the upward direction in the figure is the Y axis, and the front direction perpendicular to the drawing is the Z axis. . A central electrode Ec and a peripheral electrode Ep are arranged on the upper surface of the square plate-like support 20. Also in FIG. 6 (a), the hatching is for clearly showing the planar shape of the electrode portion, and does not show a cross section.

  FIG. 6B is a side sectional view of the structure shown in FIG. 6A taken along the XZ plane. The coordinate system is defined so that the upper surface of the plate-like support 20 is a plane included in the XY plane, and the detection point P is the origin of this coordinate system. Note that Ep (L) and Ep (R) in the drawing indicate the cross section of the left portion and the right portion of the peripheral electrode Ep.

  When the capacitive element having the structure according to the present invention is used, the peripheral electrode Ep is an electrode surrounding the periphery of the central electrode Ec, and therefore it is not necessary to make the electrodes cross three-dimensionally. Therefore, both electrodes are arranged on the same plane. That is, when the upper surface (XY plane) of the plate-like support 20 is referred to as a detection surface S, the central electrode Ec is disposed on the detection surface S so that the detection point P becomes the center point, The electrode Ep is disposed on the detection surface S so as to surround the electrode Ep so that the detection point P becomes the center point.

  Eventually, both the center electrode Ec and the surrounding electrode Ep are rotationally symmetric bodies arranged so as to have an axis passing through the detection point P and orthogonal to the detection surface S (Z axis in the illustrated example) as the central axis. Both are arranged concentrically. In the case of the illustrated example, the insulating film 21 is formed so as to cover the entire detection surface S including the center electrode Ec and the peripheral electrode Ep. The insulating film 21 functions as a protective film for the central electrode Ec and the peripheral electrode Ep.

  As shown in the side sectional view of FIG. 6B, when the capacitive element having the structure according to the present invention is employed, the central electrode Ec and the peripheral electrode Ep can be arranged on the same detection surface S. Also in the case of the basic embodiment shown in FIG. 4, the nine sets of central electrodes Ec1 to Ec9 and the nine sets of peripheral electrodes Ep1 to Ep9 can be arranged on the same detection surface S (for example, the upper surface of the support 20). Is possible. The variation in the capacitance value of the capacitive element composed of a pair of flat plate electrodes arranged adjacent to each other on the same plane will be described in detail in Section 2 below.

  After all, the object sensor shown in FIG. 4 is an object sensor having a function of detecting the position of the object M existing in the vicinity, and the support 20 that supports the predetermined detection surface S and the definition on the detection surface S are defined. A total of N capacitive elements respectively arranged in the vicinity of the plurality of N detection points P1 to PN (N = 9 in the illustrated example), and the capacitance values of these N capacitive elements Based on this, position detecting means (described later) for detecting the position of the object M is provided.

  Here, as shown in FIG. 3B, each of the N sets of capacitive elements includes a central electrode Ec arranged at the detection point P, a peripheral electrode Ep arranged so as to surround the central electrode Ec, The center electrode Ec and the peripheral electrode Ep are both supported by the plate-like support 20.

  On the other hand, the position detection means includes, for each of the N sets of capacitance elements, a capacitance value measurement unit that measures the capacitance value C between the central electrode Ec and the surrounding electrode Ep, and the measured capacitance values C. And a position specifying unit for specifying the position of the object M. A specific position specifying method by the position specifying unit will be described in detail in Section 3 below.

  In the example shown in FIG. 4, detection points P1 to P9 are defined at the positions of the respective grid points (grid points arranged in 3 rows and 3 columns) of the two-dimensional grid arranged on the detection surface S, and The capacitive elements constitute a two-dimensional array corresponding to the two-dimensional lattice. Therefore, this object sensor functions as a two-dimensional sensor capable of specifying a position in the two-dimensional direction corresponding to the two-dimensional lattice (the horizontal direction and the vertical direction in FIG. 4) for the object M present in the vicinity. To do.

  Of course, if N detection points are defined so as to be aligned on a predetermined arrangement axis on the detection surface S, and N sets of capacitive elements form a one-dimensional array along the arrangement axis, the detection points S A one-dimensional sensor capable of specifying a position in a one-dimensional direction corresponding to the arrangement axis for the existing object M can also be configured.

<<< §2. Variation of capacitance value in the present invention >>
Here, what kind of variation in the capacitance value occurs when the object M approaches the capacitive element constituted by the central electrode Ec and the peripheral electrode Ep, which is a feature of the present invention. Will be described.

  FIG. 7 is a perspective view showing a state in which the object M passes above the capacitive element shown in FIG. In FIG. 7, illustration of the insulating film 21 covering the upper surface of the plate-like support 20 is omitted. As described above, the upper surface of the support 20 is included in the XY plane of the XYZ three-dimensional orthogonal coordinate system and constitutes the detection surface S. A detection point P defined at the center of the detection surface S is the origin of the coordinate system. The center electrode Ec is a disc-shaped electrode disposed on the detection surface S with the detection point P as the center, and the peripheral electrode Ep is also an annular electrode disposed on the detection surface S with the detection point P as the center. It is.

  Now, as shown in the figure, a movement path G is defined above the X axis. The movement path G corresponds to a straight line obtained by moving the X axis in the positive direction of the Z axis by a height h. Then, how the capacitance value C between the center electrode Ec and the surrounding electrode Ep changes when the object M is moved from the left side to the right side of the drawing along the movement path G. Think about it. FIG. 8 is a side sectional view of the state of FIG. 7 taken along the XZ plane. In the figure, Ep (L) and Ep (R) are the cross section of the left portion and the right portion of the peripheral electrode Ep, and the terminal T1 and the terminal T2 are electrically connected to the peripheral electrode Ep and the center electrode Ec, respectively. This is a measurement terminal. In addition, as will be described later, the terminals T1 and T2 and the wiring thereof are actually formed on the upper surface of the support 20 or the like.

  Here, for the sake of convenience, it is assumed that the object M is a metal sphere having a center point Q, and as shown in the figure, the position of the center point Q is changed along the movement path G from Q1 → Q2 → Q3. Let's assume that object M has been moved. FIG. 9 is a graph showing a change in the capacitance value C between the terminals T1 and T2 when the object M moves on the movement path G in this way. The horizontal axis of the graph is the X coordinate value of the center point Q of the object M, and the vertical axis of the graph is the capacitance value C between the terminals T1 and T2 (that is, between the electrodes Ec and Ep). As shown in the figure, when the point Q is immediately above the detection point P (when the object M is at the position of the center point Q2 in FIG. 8), the capacitance value C takes the maximum value Cmax, and the point Q is the detection point. As the distance from P increases, the capacitance value C decreases.

  The graph shown in FIG. 9 is a graph related to the position in the one-dimensional direction with the X axis as the horizontal axis. As shown in FIG. 7, the capacitive element constituted by the central electrode Ec and the peripheral electrode Ep is detected. A rotationally symmetric body with the Z axis passing through the point P as the central axis is formed. Therefore, if the graph shown in FIG. 9 is rotated with the broken line passing through the detection point P as the central axis, a three-dimensional graph showing the capacitance value C regarding the two-dimensional position on the XY plane can be obtained. The three-dimensional graph is a mountain-shaped graph with the position of the detection point P at the top.

  Next, the reason why the graph as shown in FIG. 9 is obtained will be described. Here, first, consider a simple model as shown in FIG. FIG. 10 is a side sectional view showing the principle of generation of capacitance in the capacitive element composed of the electrodes E1 and E2 arranged on the upper surface of the plate-like support 20. FIG. 10 (a) shows an image of lines of electric force generated when a voltage is applied between the electrodes E1 and E2 in a state where the object M does not exist (a state where the object M is sufficiently away from the capacitive element). Yes. The electrodes E1 and E2 are both constituted by a flat conductive layer (for example, a metal layer), and are arranged side by side on the upper surface of the support 20 as shown. For this reason, the opposing surfaces of both electrodes E1, E2 are side portions indicated by bold lines in the figure, and many lines of electric force (indicated by broken lines in the figure) are drawn between these side faces. However, some lines of electric force are drawn between the upper and lower surfaces of the electrodes E1 and E2.

  Therefore, when this pair of electrodes E1 and E2 is grasped as the capacitive element C, the opposing surfaces of the pair of electrodes constituting the capacitive element C are side portions indicated by bold lines in the figure, and therefore the capacitance value C is compared. Take a small value. The reason why the capacitance value C at both ends of the graph of FIG. 9 is close to 0 is that only a small capacitance value C can be obtained with only the pair of electrodes E1 and E2. The value C0 shown on the vertical axis of the graph is the value of the existing capacitance existing between the electrodes E1 and E2, and as shown in FIG. Corresponds to the capacitance value held.

  On the other hand, FIG. 10B shows an image of lines of electric force generated when a voltage is applied between the electrodes E1 and E2 in a state where the object M exists in the upper space between the pair of electrodes E1 and E2. ing. Similarly to FIG. 10 (a), lines of electric force are drawn on the opposing side surfaces of both electrodes E1 and E2, but not only that, the opposing surfaces of electrode E1 and object M, and electrode E2 and object. Electric lines of force are also drawn between the opposing surfaces of M (partially indicated by bold lines in the figure). This is because the surface of the object M made of a conductive material functions as a counter electrode for the electrodes E1 and E2.

  After all, as shown in FIG. 10 (a), when the object M does not exist in the vicinity, the capacitance value C between the terminals T1 and T2 is determined solely by the existing capacitance between the electrodes E1 and E2. On the other hand, when the object M exists in the vicinity as shown in FIG. 10 (b), the capacitance value C between the terminals T1 and T2 is equal to the existing capacitance between the electrodes E1 and E2. The left additional capacity Cleft and the right additional capacity Cright generated between the object M and the object M are added.

  Subsequently, based on the above phenomenon that occurs in the simple model shown in FIG. 10, when the object M made of a metal sphere is moved along the movement path G above the capacitive element shown in FIG. Consider how the capacitance value of the capacitive element changes. FIG. 11 is a side sectional view showing the principle of generation of electrostatic capacitance of the capacitive element in the passing state shown in FIG.

  First, as shown in FIG. 11 (a), when the center point Q of the object M is positioned outside and above the peripheral electrode Ep, when a voltage is applied between the electrodes Ec and Ep, Electric field lines as shown in FIG. That is, lines of electric force are drawn between the left side portion Ep (L) of the peripheral electrode and the facing surface of the object M and between the central electrode Ec and the facing surface of the object M (surface facing the oblique position). become. Of course, in practice, some electric lines of force are also drawn between the right portion Ep (R) of the surrounding electrode and the facing surface of the object M, but the illustration is omitted because it is extremely small. In addition, electric lines of force (electric lines of force that generate an existing capacity that occurs even when the object M does not exist) are drawn between the side surface of the central electrode Ec and the side surface of the surrounding electrode Ep. The illustration is omitted here (the same applies to FIGS. 11B and 11C).

  Subsequently, as shown in FIG. 11 (b), when the center point Q of the object M is located above the intermediate position between the peripheral electrode Ep and the center electrode Ec, as shown by a broken line in the figure. Electric field lines are generated. That is, as in the case of FIG. 11A, electric lines of force are drawn between the left portion Ep (L) of the surrounding electrode and the facing surface of the object M and between the central electrode Ec and the facing surface of the object M. However, since the object M is located immediately above the electrodes Ep (L) and Ec, the density of the electric lines of force is further increased. Of course, in practice, some electric lines of force are also drawn between the right portion Ep (R) of the surrounding electrode and the opposing surface of the object M, but the illustration is omitted.

  Then, as shown in FIG. 11 (c), when the center point Q of the object M is located immediately above the detection point P, electric lines of force as shown by broken lines in the figure are generated. That is, between the left side portion Ep (L) of the surrounding electrode and the facing surface of the object M, between the central electrode Ec and the facing surface of the object M, the facing surface of the right side portion Ep (R) of the surrounding electrode and the object M Electric field lines will be drawn for all of the periods. FIG. 11 (c) is a side sectional view, but in practice, between the entire upper surface of the annular peripheral electrode Ep and the opposing surface of the object M, and the entire upper surface of the disk-shaped central electrode Ec and the object. Electric field lines will be drawn between the opposing surfaces of M, and the density of the electric field lines will be maximized.

  For this reason, as shown in the graph of FIG. 9, when the object M is positioned immediately above the detection point P, the obtained capacitance value becomes the maximum value Cmax, and as the distance from the detection point P increases, The capacitance value gradually decreases. After all, the fluctuation of the capacitance value C of the capacitive element becomes a parameter indicating the position (far / near) of the object existing in the vicinity with respect to the detection point P.

  Therefore, as shown in the example of FIG. 8, when the predetermined object M moves on the predetermined movement route G (the route of height h), the static as shown in the graph of FIG. If it is known that a change in the capacitance value C occurs, the position of the object M can be specified by measuring the capacitance value C between the terminals T1 and T2.

  However, as shown in FIG. 7, when only a single capacitive element is used, only information on the distance from the Z axis can be recognized as the position of the object M. Therefore, even when the object M always moves on the movement path G, is it positioned on the left side with respect to the YZ plane (area where the X coordinate value is negative) or positioned on the right side (the X coordinate value is Positive area) cannot be specified. When the object M moves on the plane defined by the position of height h from the XY plane (the plane defined by the equation Z = h) instead of on the movement path G, the distance from the Z axis Can be recognized, but its orientation cannot be recognized.

  Of course, when the object M moves in an arbitrary free space, only the information about the distance to the detection point P can be recognized, so that an accurate position in the three-dimensional space cannot be specified. Therefore, in the present invention, such a capacitive element is disposed in the vicinity of a plurality of N detection points defined on the detection surface, and the object M is based on the capacitance values of a total of N capacitive elements. I try to specify a more accurate location. A specific method for specifying such a position will be described in §3.

  In the above example, the object M is an example of a metal sphere, but actually, even when a human finger or the like is used as the object M, the phenomenon shown in FIG. 11 occurs. This is presumably because the finger containing moisture exhibits a dielectric property. Therefore, in practice, not only a perfect conductor but also a graph according to the graph of FIG. 9 is obtained by the approach of the object M made of various materials. However, the exact shape of the graph and the absolute value of the capacitance value C vary depending on the shape, size, and material of the object M, and also vary depending on the height h of the movement path G.

<<< §3. Method for specifying position of object in the present invention >>
As described above, with only one set of capacitive elements as shown in FIG. 7, based on the change in the capacitance value C, it is said that “some object having a certain size is approaching a certain distance”. Although vague detection can be performed, the exact position of the object cannot be detected. However, if a plurality of N capacitive elements are arranged on the detection surface S, the detailed position of the object M is specified by comparing the capacitance values of the N capacitive elements with each other. It becomes possible. Here, a specific method for specifying such a position will be described.

  The middle part of FIG. 12 is a top view of a structure in which three sets of capacitive elements are arranged on a plate-like support 20 having detection areas A1, A2, and A3 defined on the upper surface. The upper part of FIG. It is a graph which shows the change of the electrostatic capacitance value of each capacitive element when the target object M passes above a structure. The detection areas A1, A2, and A3 are square areas and are arranged side by side in the X-axis direction. Detection points P1, P2, and P3 are defined at the centers of the detection areas A1, A2, and A3. Capacitance elements C1, C2, and C3 are arranged around the detection points P1, P2, and P3, respectively. Yes.

  Here, each of the capacitive elements C1, C2, and C3 is a capacitive element having the structure shown in FIG. That is, the capacitive element C1 is composed of the central electrode Ec1 and the peripheral electrode Ep1, the capacitive element C2 is composed of the central electrode Ec2 and the peripheral electrode Ep2, and the capacitive element C3 is composed of the central electrode Ec3 and the peripheral electrode Ep3. Composed. Here, the capacitance values between a pair of electrodes constituting each of the capacitive elements C1, C2, and C3 are represented as C1, C2, and C3 using the same reference numerals.

  As shown in the figure, the detection points P1, P2, and P3 are points defined at equal intervals on the X axis. Therefore, as in the example shown in FIG. 7, the movement path G is defined as a straight line obtained by moving the X axis in the positive direction of the Z axis by the height h, and along the movement path G from the left side to the right side of the figure. Let us consider how the capacitance values C1, C2, and C3 change when the object M is moved. The upper graphs G1, G2, and G3 in FIG. 12 show such fluctuations. The horizontal axis of the graph represents the X coordinate value of the center point Q of the object M, and the vertical axis of the graph represents each capacitance value C. In addition, the lower end scale of the vertical axis indicates the existing capacitance value C0 of each of the capacitive elements C1, C2, and C3 (original capacitance value when the object M does not exist).

  The fluctuations of the capacitance values C1, C2, and C3 are as shown in the graphs G1, G2, and G3. The fluctuation of the capacitance value C of the capacitive element shown in FIG. This makes it easy to understand. Considering that such graphs G1, G2, and G3 are obtained, it can be seen that the approximate position of the object M can be identified based on the three sets of capacitance values C1, C2, and C3.

  For example, when the center point Q of the object M is located at the position indicating the X coordinate value ξ on the movement route G, the capacitance values of the capacitive elements C1, C2, C3 are respectively as shown in the figure. C1 = ξ1, C2 = ξ2, C3 = ξ3. Therefore, if it is assumed that the object M moves along the moving path G defined at the position of the height h above the X axis, three sets of measurement values ξ1, ξ2, and ξ3 are obtained to obtain the object M The position of the center point Q can be specified as the point indicating the X coordinate value ξ on the movement route G.

  Even if the height h of the movement path G is arbitrarily changed or the size of the object M is arbitrarily changed, if the relation of ξ2> ξ1> ξ3 is obtained, the object As an approximate position of M, information “above the point between the detection points P1 and P2” can be obtained. The embodiment shown in FIG. 12 is an example in which three sets of capacitive elements are arranged one-dimensionally along the X axis. However, if the capacitive elements are arranged two-dimensionally as in the embodiment shown in FIG. It becomes possible to specify the two-dimensional position.

  Hereinafter, an example in which the two-dimensional position of the object M is specified will be described with respect to an example using 81 sets of capacitive elements arranged in 9 rows and 9 columns. Now, let us consider a case where a capacitance value distribution as shown in FIG. 13 is obtained for 81 sets of capacitive elements arranged in 9 rows and 9 columns on the detection surface S formed of the XY plane. The distribution diagram shown in FIG. 13 shows the result of the measurement of the capacitance within the range of 0 to 28 for each of 81 sets of capacitive elements, and the value in the cell C (1, 1). “0” is the capacitance value of the capacitive element in the first row and first column, the value “0” in the cell C (1,2) is the capacitance value of the capacitive element in the first row and second column,. The value “0” in the cell C (9, 9) indicates the capacitance value of the capacitive element in the ninth row and the ninth column. Here, for convenience of explanation, it is assumed that the existing capacity value C0 = 0.

  In general, when an object M having a size smaller than the vertical and horizontal dimensions of the detection surface S on which the capacitive element is disposed is present above the detection surface S, each capacitive element on the detection surface S The distribution of the capacitance value C is as shown in a three-dimensional graph Gxy shown in FIG. In the illustrated example, an XYC three-dimensional orthogonal coordinate system is defined by taking the detection surface S on which each capacitive element is arranged on the XY plane and taking the capacitance value C of each capacitive element on the third coordinate axis. This is an example in which a three-dimensional graph Gxy is drawn on the coordinate system. As shown in the figure, the three-dimensional graph Gxy has a mountain shape.

  Now, as shown in FIG. 14, a predetermined threshold value Ct is set for the capacitance value C on the XYC three-dimensional orthogonal coordinate system, and a mountain-shaped graph Gxy is expressed by the expression “C = Ct”. A cutting plane Bt obtained by cutting along a plane is defined. Then, a significant region St as shown is obtained as an orthogonal projection image of the cut surface Bt onto the XY plane. Here, if a capacitive element whose capacitance value equal to or greater than the predetermined threshold Ct is measured is referred to as a “significant element”, this significant region St is a detection point (only) where the significant element is arranged. The position on the detection surface S includes the position on the detection surface S of the object M, that is, the position on the two-dimensional plane when projected onto the XY plane (position on the XY plane). Will be shown.

  In the case of the example shown in FIG. 14, after determining the significant area St, the center of gravity g (Xg, Yg) of the significant area St is obtained, and the position of the center of gravity g (Xg, Yg) It is specified as a position on the dimension plane. After all, in this example, the coordinate value (Xg, Yg) of the barycentric point g is output as a detection result. The output indicates a detection result that “the center point Q of the object M is located immediately above the center of gravity g (Xg, Yg)”. In calculating the barycentric point g, a weighted average using each capacitance value as a weight may be used.

  As described in §1, the object sensor according to the present invention includes position detection means for detecting the position of the object M, and this position detection means is a capacitance value for measuring the capacitance value of each capacitive element. A measuring unit; and a position specifying unit that specifies the position of the object M based on each measured capacitance value. Here, when the above-described method described with reference to FIG. 14 is employed, the position specifying unit determines that a capacitive element having a capacitance value greater than or equal to a predetermined threshold Ct is determined as a significant element, and this significance is determined. A region on the detection surface S including the detection point where the element is arranged is recognized as a significant region St, and the position of the significant region St on the detection surface S is output as a position on the two-dimensional plane of the object M. Become.

  The distribution diagram illustrated in FIG. 13 shows the distribution of capacitance values for 81 sets of capacitive elements arranged on the detection surface S formed of the XY plane. The capacitance in the fourth row and the fourth column is shown in FIG. The capacitance value “28” of the element shows the maximum value, and the capacitance value decreases as it goes around the device.

  For such a measurement result, for example, if the threshold value Ct is set to Ct = 20, the region surrounded by the thick line in FIG. 15 is recognized as the significant region St. In other words, all the capacitive elements in the significant region St are significant elements whose electrostatic capacitance values of “threshold value Ct = 20” or more are measured. On the other hand, if the threshold value Ct is set to Ct = 10 for the same measurement result, the region surrounded by the thick line in FIG. 16 is recognized as the significant region St. That is, all the capacitive elements in the significant region St are significant elements whose electrostatic capacitance values of “threshold value Ct = 10” or more are measured.

  As described above, the significant region St is a region whose shape and area vary depending on the setting of the threshold value Ct. In general, if the threshold value Ct is set high, the area of the significant region St becomes small, and if the threshold value Ct is set low, the area of the significant region St becomes large. Of course, the coordinate values (Xg, Yg) of the barycentric point g also vary depending on the setting of the threshold value Ct. However, in general, the position fluctuation of the barycentric point g due to the threshold value Ct is not so large, so even if an arbitrary value is set as the threshold value Ct, the position of the barycentric point g is It can be used as information with a certain degree of accuracy indicating the two-dimensional position of the object M.

  On the other hand, if the object M is not an object having an arbitrary shape and size but a predetermined specific object (for example, a human finger or a specific touch pen), the significant region is assumed. The area of St can also be used as useful information indicating the position of the object M. For example, in the case of an object sensor limited to applications such as a touch panel operated by a user with a finger, the position specifying unit can perform processing limited to a specific object “human finger”. The value of the area of St can be output as information indicating the height of the “human finger” from the detection surface S.

  That is, when the “human finger” (object M) is present at a high position (a position away from the detection surface S), the influence on the fluctuation of the capacitance value is small, and thus the peaks shown in FIG. The shape graph Gxy is a small mountain, but when the “human finger” (object M) is approaching to a low position (position close to the detection surface S), there is an effect on the fluctuation of the capacitance value. Since it becomes large, the mountain-shaped graph Gxy becomes a large mountain. Accordingly, if an appropriate fixed value is set in advance as the threshold value Ct, the area of the significant region St is reduced because a small mountain is cut by a plane “C = Ct” in the former case. In the latter case, since the large mountain is cut by the plane “C = Ct”, the area of the significant region St becomes large. As described above, when performing detection limited to a specific object whose size, shape, material, and the like are determined to some extent, use the value of the area of the significant region St as information indicating the height of the object. Can do.

  On the other hand, if it is assumed that an object having various sizes approaches, but the object always appears at a position having a specific height h, the position specifying unit sets the area value of the significant region St as follows: It is possible to output as information indicating the size of an arbitrary object existing at the specific height h from the detection surface S.

  That is, the detection surface S is defined on the XY plane in the XYZ three-dimensional orthogonal coordinate system, and a plane in which an arbitrary object M is “Z = h” (a plane separated from the detection surface S by a height h). If the premise is that the object M moves along, the height position of the object M is always constant. Therefore, if the area of the significant region St is large, the size of the object M (size in the direction parallel to the XY plane) is also large. If the area of the significant region St is small, the size of the object M is small. It will be. Therefore, the value of the area of the significant region St can be used as information indicating the size of the detected object.

<<< §4. Example with specific wiring >>>
In §1, the object sensor using the conventional capacitive element shown in FIG. 2 is compared with the object sensor using the capacitive element according to the present invention shown in FIG. Here, since the former employs a structure in which elongated linear electrodes are arranged in a grid pattern in the vertical and horizontal directions, the merit of increasing the arrangement density of the local capacitive elements and improving the resolution can be obtained, but the detection sensitivity is low. As described above, the method has a problem that it is not suitable for detecting an object in a contact state. On the other hand, since the latter has a structure in which the center electrode and the peripheral electrode are arranged, it is not suitable for the purpose of increasing the arrangement density of the capacitive elements, but sufficient detection sensitivity can be obtained even if the object M is not in contact. As described above, it has the advantage of being suitable for object detection in a non-contact state.

  Here, the detection sensitivity when the object M is in a non-contact state will be further described. In the case of the conventional capacitive element, as shown in FIG. 5, the row direction electrode Ex and the column direction electrode Ey In a three-dimensionally intersecting overlapping area (square area in FIG. 5 (a)) in the vicinity of the detection point P, a local capacitive element is configured by a pair of upper and lower electrodes. Therefore, when a voltage is applied between the pair of upper and lower electrodes, electric lines of force are drawn in the vertical direction, and even if the target M does not exist in this localized capacitance element, it is somewhat. Existing capacity value C0 is expected.

  Of course, when the object M in a non-contact state approaches the structure shown in FIG. 5B, the capacitance value C of the localized capacitance element increases by ΔC to C = C0 + ΔC. In general, the variation ΔC is smaller than the existing capacity value C0. The presence of the non-contact state object M is detected as this variation ΔC, so even if the total capacitance value C = C0 + ΔC is measured, it is difficult to detect the variation ΔC with sufficient accuracy. is there.

  On the other hand, in the case of the capacitive element according to the present invention, it is not constituted by a pair of electrodes opposed vertically, but by a pair of electrodes arranged adjacent to each other in the lateral direction. In this way, when a voltage is applied between a pair of electrodes arranged adjacent to each other in the horizontal direction, lines of electric force are mainly drawn between the side surfaces as illustrated in FIG. 10 (a). Therefore, in the case of the capacitive element according to the present invention, the existing capacitance value C0 when the object M does not exist is considerably small.

  Then, as shown by the electric lines of force drawn by broken lines in FIG. 11, when the object M approaches upward, a large variation ΔC occurs in the capacitance value even in a non-contact state. That is, the variation ΔC is a large value comparable to the existing capacity value C0. Since the presence of the non-contact state object M is detected as the variation ΔC, the variation ΔC can be detected with sufficient accuracy by measuring the total capacitance value C = C0 + ΔC. .

  As described above, the capacitive element according to the present invention has an advantage that it is suitable for detecting the presence of the non-contact state object M. However, with regard to the convenience of wiring for each electrode constituting the capacitive element, the conventional capacitive element is known. The type capacitive element is superior. As can be seen from FIG. 2, in the case of a conventional object sensor, the row-direction electrode Ex and the column-direction electrode Ey function as electrodes for forming a localized capacitance element. The whole also functions as wiring for the electrodes. Therefore, in the conventional object sensor shown in FIG. 2, it is not necessary to provide individual wirings for the individual electrodes constituting the local capacitive element.

  However, in the case of the object sensor according to the present invention, each capacitive element has the independent center electrode Ec and peripheral electrode Ep, and therefore, separate wiring for each electrode is required. For example, in the case of the embodiment shown in FIG. 4, in order to constitute a total of nine sets of capacitive elements, nine sets of central electrodes Ec1 to Ec9 and nine sets of peripheral electrodes Ep1 to Ep9 are provided on the support 20. However, each of these electrodes itself does not have a function as a wiring. Therefore, it is necessary to provide wiring between each electrode and a capacitance value measurement unit (capacitance value measurement circuit) for measuring the capacitance value of each capacitance element.

  In §4, two examples of specific wiring are described for the object sensor according to the basic embodiment of the present invention shown in FIG.

<4-1. Example of wiring using sub-insulating layer>
First, an example in which wiring is performed using a sub-insulating layer will be described as a first embodiment in which specific wiring is performed. When manufacturing the object sensor according to the present invention, as shown in FIG. 6 (b), in practice, an insulation functioning as a protective film so as to cover the entire surface of the detection surface S including the center electrode Ec and the peripheral electrode Ep. Layer 21 is preferably formed. In the illustrated example, the center electrode Ec and the peripheral electrode Ep are both embedded in the insulating layer 21. Here, the insulating layer in which the central electrode Ec and the peripheral electrode Ep are embedded is referred to as a main insulating layer. In the embodiment described here, a sub-insulating layer is provided separately from the main insulating layer, and necessary wiring is embedded in the sub-insulating layer.

  FIG. 17A is a top view of an embodiment in which wiring is performed using a sub-insulating layer (hatching is for clearly showing the electrode shape, not for showing a cross section). 17 (b) is a side sectional view showing a state in which this is cut at the position of the cutting line 17b-17b. The example shown in FIG. 17 is an example in which wiring is applied to the basic embodiment shown in FIG. 4, and nine sets of capacitive elements C1 to C9 are arranged on a plate-like support 20. The point that each of the capacitive elements C1 to C9 is constituted by the central electrodes Ec1 to Ec9 and the peripheral electrodes Ep1 to Ep9 is as already described in section 1.

  Again, for convenience of explanation, an XYZ three-dimensional orthogonal coordinate system as shown is defined. That is, the right direction in FIG. 17A is the X axis, the upper direction is the Y axis, and the front direction perpendicular to the paper surface is the Z axis, and the right direction in FIG. 17B is the X axis, the upper direction is the Z axis, and the paper surface is vertical. The back direction is the Y axis.

  As shown in the side sectional view of FIG. 17B, a first insulating layer 22 is formed on the upper surface of the plate-like support 20, and a second insulating layer 23 is formed on the upper surface. Has been. Here, the second insulating layer 23 is the main insulating layer described above, and the central electrode Ec and the peripheral electrode Ep are embedded therein. The second insulating layer 23 also functions as a protective layer. Note that the second insulating layer 23 is not shown in the top view of FIG. That is, the components drawn with a solid line in FIG. 17 (a) and hatched are components formed on the upper surface of the first insulating layer 22, and the second insulating layer 23 An embedded component. On the other hand, the constituent elements drawn with broken lines in FIG. 17A are constituent elements formed on the upper surface of the support 20 and are constituent elements embedded in the first insulating layer 22. .

  As shown in the top view of FIG. 17A, nine sets of capacitive elements C1 to C9 are arranged in a matrix of 3 rows and 3 columns. The three sets of peripheral electrodes belonging to the same row are connected to each other by a lateral wiring layer parallel to the X axis, and further connected to the rightmost terminal. Specifically, the peripheral electrodes Ep1, Ep2, Ep3 belonging to the first row are connected to the terminal Tx1 by the lateral wiring layers Wx1, Wx2, Wx3, and the peripheral electrodes Ep4, belonging to the second row. Ep5, Ep6 are connected to the terminal Tx2 by the horizontal wiring layers Wx4, Wx5, Wx6, and the peripheral electrodes Ep7, Ep8, Ep9 belonging to the third row are terminals by the horizontal wiring layers Wx7, Wx8, Wx9. Connected to Tx3.

  The second insulating layer 23 in the side sectional view of FIG. 17B shows a state where the peripheral electrodes Ep7, Ep8, Ep9 belonging to the third row of the matrix are connected to the terminal Tx3. A wiring contact hole H shown in FIG. 17B is a contact hole opened in the second insulating layer 23, and is used for external wiring to the terminal Tx3. Similarly, external wiring through the contact hole for wiring is made for the terminals Tx1 and Tx2.

  On the other hand, as shown by the broken line in the top view of FIG. 17 (a), the three sets of central electrodes belonging to the same column are connected to each other by a vertical wiring layer parallel to the Y axis, and further connected to the lower terminal. Has been. Specifically, the center electrodes Ec1, Ec4, Ec7 belonging to the first column are connected to the terminal Ty1 by the vertical wiring layer Wy10, and the center electrodes Ec2, Ec5, Ec8 belonging to the second column are The central electrodes Ec3, Ec6, Ec9 belonging to the third column are connected to the terminal Ty3 by the vertical wiring layer Wy30.

  In the first insulating layer 22 in the side sectional view of FIG. 17 (b), cross sections of three vertical wiring layers Wy10, Wy20, Wy30 are shown. Each of the vertical wiring layers Wy10, Wy20, Wy30 is embedded in the first insulating layer 22 (sub-insulating layer), whereas each of the central electrodes Ec1 to Ec9 has a second insulating layer 23 (main insulating layer). Therefore, an interlayer wiring layer for connecting the two in the vertical direction is provided. A black circle drawn at the center position of each of the center electrodes Ec1 to Ec9 in FIG. 17A indicates this interlayer wiring layer.

  FIG. 17B is a side sectional view showing an interlayer wiring layer W7 connecting the central electrode Ec7 and the vertical wiring layer Wy10, an interlayer wiring layer W8 connecting the central electrode Ec8 and the vertical wiring layer Wy20, and the central electrode. An interlayer wiring layer W9 that connects Ec9 and the vertical wiring layer Wy30 is shown. These interlayer wiring layers are actually composed of a conductive material filled in a wiring contact hole opened in the first insulating layer 22. Although not shown in the drawing, wiring contact holes that penetrate the first insulating layer 22 and the second insulating layer 23 are provided above the terminals Ty1, Ty2, and Ty3. External wiring for the terminals Ty1, Ty2, and Ty3 is made through the contact holes.

  Of course, if the terminals Tx1 to Tx3, Ty1 to Ty3 are extended to the side end faces of the insulating layers 22 and 23, the external wiring is directly connected to each terminal exposed from the side end face without using the wiring contact hole H. Can also be applied.

  Although such a wiring configuration is very simple, it is possible to measure the capacitance value of an arbitrary capacitive element by the following method, and is also very efficient. FIG. 18 is a circuit diagram (partially a block diagram) showing an example of the position detecting means 50 used in the embodiment shown in FIG. As described in §1, the object sensor according to the present invention is provided with the position detection means 50 for detecting the position of the object M based on the capacitance values of a plurality of N capacitive elements. As shown in the figure, the position detection means 50 specifies the position of the object M based on the capacitance value measurement unit 51 that measures the capacitance value of each capacitance element and the measured capacitance values. A position specifying unit 52.

  The position detecting means 50 shown in FIG. 18 is applied to the embodiment shown in FIG. Accordingly, the terminals Tx1, Tx2, and Tx3 shown in the circuit diagram of the capacitance value measuring unit 51 correspond to the respective terminals shown at the right end of FIG. Terminals Ty1, Ty2, Ty3 shown in the circuit diagram correspond to the terminals shown at the lower end of FIG. 17 (a). The terminals Tx1 to Tx3 are connected to the terminal Ta via the changeover switches SWx1 to SWx3, and the terminals Ty1 to Ty3 are connected to the terminal Tb via the changeover switches SWy1 to SWy3. The capacitance value C is measured by the measuring circuit m. Since the measurement circuit m for measuring the capacitance value C is a known circuit, a detailed circuit diagram thereof is omitted here.

  FIG. 19 is a table showing a switching operation when the capacitance value measurement unit 51 shown in FIG. 18 measures the capacitance values of the nine capacitive elements C1 to C9 shown in FIG. 17, and is shown in the left column. In addition, ON / OFF switching states of the changeover switches SWx1 to SWx3 and SWy1 to SWy3 when the capacitance values of the capacitive elements C1 to C9 are measured are shown. For example, when measuring the capacitance value of the capacitive element C1, the change-over switches SWx1 and SWy1 may be turned on and the other change-over switches may be turned off. Then, the capacitance value measured between the terminals Ta and Tb is the capacitance value between the terminal Tx1 and the terminal Ty1 shown in FIG. 17, that is, the capacitance value of the capacitive element C1.

  Therefore, it is possible to measure the capacitance values of the capacitive elements C1 to C9 by switching the selector switches SWx1 to SWx3 and SWy1 to SWy3 according to the table of FIG. The position specifying unit 52 performs a process of specifying the position of the object M based on the capacitance value thus obtained. The specific processing contents are as already described in §3.

  The embodiment shown in FIGS. 17 to 19 is for an example in which nine sets of capacitive elements are arranged on the detection surface S in three rows and three columns, but N sets (N = N = N rows arranged in I rows and J columns). The structure of an object sensor using a capacitor element of I × J) is described as a general theory as follows. First, the detection surface S is defined on the XY plane in the XYZ three-dimensional orthogonal coordinate system. Then, I horizontal lattice lines parallel to the X axis and J vertical lattice lines parallel to the Y axis are defined, and lattice points are defined at respective intersection positions of these lattice lines. As a result, a total of N lattice points are defined as a matrix of I rows and J columns.

  Then, with the individual lattice points as the detection points P, as described in §1, the capacitive element including the central electrode Ec and the peripheral electrode Ep is arranged at the position of each detection point P. As a result, a total of N capacitive elements are arranged in a matrix of I rows and J columns. Therefore, wiring is performed so that the J peripheral electrodes Ep1 to EpJ arranged along the same horizontal grid line are connected to each other by the horizontal wiring layer Wx along the horizontal grid line. Wiring is performed so that the I central electrodes Ec1 to EcI arranged along the vertical line are connected to each other by the vertical wiring layer Wy along the vertical grid line. The example shown in FIG. 17 is an example in which I = 3 and J = 3, a total of N capacitive elements are arranged in a matrix of 3 rows and 3 columns, and the wiring described above is applied.

  In order to perform such wiring, in the embodiment shown in FIG. 17, the first insulating layer 22 is formed on the upper surface of the support 20, and the second insulating layer 23 is formed on the upper surface of the first insulating layer 22. Forming. When the second insulating layer 23 is called a main insulating layer and the first insulating layer 22 is called a sub-insulating layer, the central electrodes Ec1 to Ec9, the peripheral electrodes Ep1 to Ep9, and the peripheral electrodes Ep1 to Ep9 are displayed. The peripheral electrode wiring layers Wx1 to Wx9 (in the case of FIG. 17 (a), the lateral wiring layer) for electrically connecting the capacitor to the capacitance measuring unit 51 are embedded in the main insulating layer, and the central electrode The central electrode wiring layers Wy10 to Wy30 (in the case of FIG. 17A, the vertical wiring layer) for electrically connecting Ec1 to Ec9 to the capacitance value measuring unit 51 are embedded in the sub-insulating layer. Further, an interlayer wiring layer (W7 to W9 in the case of FIG. 17B) penetrating the boundary surface between the main insulating layer and the sub insulating layer is formed between the central electrodes Ec1 to Ec9 and the central electrode wiring layer. ing.

  In the case of the embodiment shown in FIG. 17, the first insulating layer 22 formed on the upper surface of the support 20 is used as a sub-insulating layer, and the second insulating layer 23 formed on the upper surface is used as a main insulating layer. However, conversely, the first insulating layer 22 formed on the upper surface of the support 20 may be the main insulating layer, and the second insulating layer 23 formed on the upper surface may be the sub-insulating layer.

  However, in practice, as in the embodiment shown in FIG. 17, it is preferable that the lower first insulating layer 22 be a sub-insulating layer and the upper second insulating layer 23 be a main insulating layer. This is because if the second insulating layer 23 that is the upper layer is the main insulating layer, the detection surface S on which the center electrode Ec and the peripheral electrode Ep are disposed is the bottom surface of the second insulating layer 23 that is the upper layer. This is because the distance between each electrode and the object M becomes smaller and higher detection sensitivity can be obtained.

  Similarly, when the configuration of the capacitance value measuring unit 51 shown in FIG. 18 is described in general terms, the capacitance value measuring unit 51 includes the i-th (1 ≦ i ≦ I) lateral wiring layer and the j-th (1 ≦ j ≦ J) measuring a capacitance value between the selector switch for selecting the vertical wiring layer and the selected i-th horizontal wiring layer and j-th vertical wiring layer And a measurement circuit m for obtaining the capacitance value of the capacitive element arranged at the detection point located in the i-th row and the j-th column, and any detection can be performed by switching the selection target with the changeover switch. It can be said that it is a component that measures the capacitance value of the capacitive element arranged at the point.

<4-2. Example in which electrode formation layer is divided into two layers for wiring>
Subsequently, an example in which wiring is performed by dividing the electrode forming layer into two layers will be described as a second embodiment in which specific wiring is performed. In the case of this embodiment, the center electrode Ec and the peripheral electrode Ep are embedded in different insulating layers. Here, for convenience of explanation, a structure in which only one set of capacitive elements is formed will be described with reference to FIG. FIG. 20 (a) is a top view of such a structure, and FIG. 20 (b) is a side sectional view of the structure cut along an XZ plane.

  In the structure shown in FIG. 20 (a), a disk-shaped central electrode Ec and an annular peripheral electrode Ep surrounding the disk-shaped central electrode Ec are arranged on the upper surface of the flat plate-like support 20, and a set of capacitive elements is arranged. It is configured and further wired. The hatching shown in FIG. 20 (a) is for clearly showing the electrode shape, not for showing the cross section. As shown in the figure, the central electrode Ec is wired by the vertical wiring layer Wy, and is electrically connected to the terminal Ty, and the peripheral electrode Ep is wired by the horizontal wiring layer Wx. And electrical connection is made to the terminal Tx.

  The feature of the embodiment described here is that the central electrode Ec and the vertical wiring layer Wy are formed so as to be embedded in the first insulating layer 22, and the peripheral electrode Ep and the horizontal wiring layer Wx are embedded in the second insulating layer 23. And the two are electrically insulated from each other. That is, as shown in the top view of FIG. 20 (a), when only the planar positional relationship is seen, the central electrode Ec is surrounded by the surrounding electrode Ep. Although intersecting with the surrounding electrode Ec, by adopting the above two-layer structure, the intersecting portion is actually a three-dimensional intersection, and the insulation state between the two is maintained.

  The state of this three-dimensional intersection is clearly shown in the side sectional view of FIG. FIG. 20B is a cross-sectional view of the structure shown in FIG. 20A cut along the X-axis. This figure shows a state in which a first insulating layer 22 is formed on the upper surface of the flat support 20 and a second insulating layer 23 is formed on the upper surface of the first insulating layer 22. Yes. In the case of this example, the first insulating layer 22 serves as a central electrode forming layer for embedding the central electrode Ec, the vertical wiring layer Wy, and the terminal Ty, and the second insulating layer 23 includes the peripheral electrode Ep. , Function as a peripheral electrode forming layer for embedding the lateral wiring layer Wx and the terminal Tx. Although not appearing in FIG. 20B, the vertical wiring layer Wy and the terminal Ty are formed on the upper surface of the support 20 in the same manner as the central electrode Ec.

  In the example shown in FIG. 20B, a wiring contact hole H is formed in the second insulating layer 23 so that the terminal Tx can be connected to an external circuit (capacitance value measuring unit 51). Although not shown, a wiring contact hole for connecting the terminal Ty to an external circuit is also provided. Of course, if the terminals Tx and Ty are extended to the side end faces of the insulating layers 22 and 23, the external wiring is directly connected to the terminals Tx and Ty exposed from the side end faces without using the wiring contact holes H. It can also be applied.

  FIG. 21 is a side sectional view showing an example in which the layer structure shown in FIG. That is, in this example, the first insulating layer 22 serves as a peripheral electrode forming layer, and the second insulating layer 23 serves as a central electrode forming layer. Therefore, the central electrode Ec, the vertical wiring layer Wy, and the terminal Ty are embedded in the second insulating layer 23, and the peripheral electrode Ep, the horizontal wiring layer Wx, and the terminal Tx are embedded in the first insulating layer 22. ing.

  Eventually, in the case of the second embodiment in which specific wiring is applied, one of the first insulating layer 22 and the second insulating layer 23 serves as a central electrode forming layer, and the other forms a peripheral electrode. If each layer is made to serve as a layer, the center electrode Ec of each capacitor element is embedded in the center electrode formation layer, and the peripheral electrode Ep of each capacitor element is embedded in the peripheral electrode formation layer, each layer The hierarchical relationship of the structure is not questioned.

  FIG. 22 shows a structure in which the wiring form according to the second example in which the electrode forming layer is divided into two layers is applied to the basic embodiment using nine sets of capacitive elements shown in FIG. FIG. 22 (a) is a top view of the structure (hatching is for clearly showing the electrode shape, not for showing a cross section), and FIG. 22 (b) shows this. It is a sectional side view which shows the state cut | disconnected in the position of the cutting line 22b-22b. Again, for convenience of explanation, an XYZ three-dimensional orthogonal coordinate system as shown in the figure is defined. That is, the right direction in FIG. 22 (a) is the X axis, the upward direction is the Y axis, and the front vertical direction is the Z axis. The right direction in FIG. 22 (b) is the X axis, the upward direction is the Z axis, The back direction is the Y axis.

  Compared with the first embodiment shown in FIG. 17 in the second embodiment shown in FIG. 22, the point that nine sets of capacitive elements C1 to C9 are arranged on the plate-like support 20, and each capacitance There is no difference in that the elements C1 to C9 are constituted by the central electrodes Ec1 to Ec9 and the peripheral electrodes Ep1 to Ep9, but there is a slight difference in the layer structure for embedding each component.

  As shown in FIG. 22 (a), the disk-shaped central electrodes Ec1 to Ec9 are wired to the terminals Ty1 to Ty3 via the vertical wiring layers Wy1 to Wy9. Similarly, the annular peripheral electrodes Ep1 to Ep9 are wired to the terminals Tx1 to Tx3 via the lateral wiring layers Wx1 to Wx9. However, since the layer structure shown in FIG. 20 is adopted, the disk-shaped central electrodes Ec1 to Ec9, the vertical wiring layers Wy1 to Wy9 and the terminals Ty1 to Ty3 thereof are provided on the flat support 20. It is formed on the upper surface and is embedded in the first insulating layer 22. In the sectional side view of FIG. 22B, three sets of central electrodes Ec7 to Ec9 embedded in the first insulating layer 22 are shown.

  On the other hand, the annular peripheral electrodes Ep1 to Ep9, the lateral wiring layers Wx1 to Wx9 thereof, and the terminals Tx1 to Tx3 are formed on the upper surface of the first insulating layer 22, and the second insulating layer 23. Embedded in. In the side sectional view of FIG. 22B, the peripheral electrodes Ep7 to Ep9 in the third row of the matrix and the lateral wiring layers Wx7 to Wx9 for connecting them to the terminal Tx3 are shown as the second insulating layer. The state embedded in 23 is shown. Of course, similarly to the first embodiment shown in FIG. 17, in the second embodiment shown in FIG. 22, the terminals Tx1 to Tx3 and Ty1 to Ty3 are connected via the wiring contact holes H. Wiring to the outside is possible.

  The embodiment shown in FIG. 22 adopts the layer structure shown in FIG. 20, but of course, it is also possible to adopt the layer structure shown in FIG. 21 in which the layer structure is turned upside down. Eventually, in the second embodiment shown in FIG. 22, the first insulating layer 22 is formed on the upper surface of the support 20, and the second insulating layer 23 is formed on the upper surface of the first insulating layer 22. Is the same as that of the first embodiment shown in FIG. 17 except that one of the first insulating layer 22 and the second insulating layer 23 is called a central electrode forming layer and the other is called a surrounding electrode forming layer. The central electrodes Ec1 to Ec9 and the central electrode wiring layers Wy1 to Wy9 for electrically connecting the central electrodes Ec1 to Ec9 to the capacitance value measuring unit 51 (in the case of FIG. 22 (a), the vertical wiring layer) Are embedded in the central electrode forming layer, and the peripheral electrodes Ep1 to Ep9 and the peripheral electrode wiring layers Wx1 to Wx9 for electrically connecting the peripheral electrodes Ep1 to Ep9 to the capacitance value measuring unit 51 (FIG. 22). In the case of (a), the lateral wiring layer) is embedded in the surrounding electrode formation layer I would have.

  As described above, the first embodiment shown in FIG. 17 and the second embodiment shown in FIG. 22 have a slight difference in layer structure, but the respective center electrodes Ec1 to Ec9 and the surrounding electrodes Ep1 to Ep9 are different from each other. The connection relationships between the terminals Tx1 to Tx3 and Ty1 to Ty3 are exactly the same. Therefore, also in the second embodiment shown in FIG. 22, the position of the object M can be specified using the position detecting means 50 shown in FIG. 18 as it is.

  However, from the viewpoint of detection sensitivity, the first embodiment shown in FIG. 17 is superior to the second embodiment shown in FIG. In the case of the first embodiment, this is because the central electrodes Ec1 to Ec9 and the peripheral electrodes Ep1 to Ep9 are all arranged on the same detection surface S as shown in FIG. This is because the capacitance value fluctuates more greatly due to the approach of the object M. In the case of the second embodiment, as shown in FIG. 22B, the formation surface of the central electrodes Ec1 to Ec9 and the formation surface of the peripheral electrodes Ep1 to Ep9 are not the same surface. For this reason, the distance between the one electrode and the object M is slightly larger than that of the other electrode, and the variation in the capacitance value due to the approach of the object M is slightly reduced. For this reason, the detection sensitivity of the second embodiment is slightly lower than that of the first embodiment.

<4-3. Examples of materials and dimensions of each part>
§4-1 describes the first embodiment in which specific wiring is performed with reference to FIG. 17, and §4-2 describes the second embodiment in which specific wiring is performed with reference to FIG. 22. Examples have been described. Here, when actually manufacturing the object sensor based on each of these embodiments, examples of materials and dimensions of each part will be briefly described.

  First, the plate-like support 20 can be constituted by a rigid substrate such as a glass epoxy substrate or a ceramic substrate, or by so-called FPC (Flexible Printed Circuits) using a flexible film such as a polyimide film or a PET film. It can also be constituted by a sheet of silicone rubber or the like. In the case where the support body 20 is used for an application to be attached to a curved surface of an arbitrary shape such as a fingertip of a robot arm, it is preferable that the support body 20 has flexibility, so that the support body 20 made of a flexible film is used. do it.

  On the other hand, the center electrode Ec and the peripheral electrode Ep may be made of a metal such as aluminum or copper, or other conductive material, for example. Specifically, these conductive materials can be formed by a method such as printing, potting or stamping. The same applies to each wiring layer and terminal.

  Moreover, what is necessary is just to comprise the 1st insulating layer 22 and the 2nd insulating layer 23 by resin layers, such as a polyimide, for example. These insulating layers are layers in which each electrode or wiring layer is embedded, but in the actual manufacturing process, after forming each electrode and wiring layer, a resin is poured to cover them and cured. Can be formed. Each electrode is formed directly on the upper surface of the support 20 or indirectly through another insulating layer, and the upper surface of each electrode is covered and protected by the insulating layer.

  It is as follows when the actual dimension of each part about the structure which concerns on the Example of FIG. 17 which this inventor made as an experiment is described for reference. First, as the support 20, a plate member having a thickness of 1 mm and a square having a side of 80 mm was used. The thickness of the central electrode Ec, the peripheral electrode Ep, each wiring layer, and each terminal was 20 μm, and the thickness of the first insulating layer 22 and the second insulating layer was 30 μm. Further, in each part shown in the top view of FIG. 17 (a), the central electrode Ec is a disk having a diameter of 5 mm, the peripheral electrode Ep is an annular structure having an inner diameter of 8 mm and an outer diameter of 10 mm, and wirings Wx1 to Wx9, Wy10 to Wy30. The thickness of was 1 mm. The vertical and horizontal pitches (the pitches of the detection points P) of the capacitive elements C1 to C9 are 20 mm.

  Of course, the materials and dimensions of the respective parts exemplified in §4-3 are shown as reference examples, and in carrying out the present invention, the materials and dimensions of the respective parts are not limited to the above reference examples. . The material and dimensions of each part should be appropriately determined according to the use and price of each object sensor provided as a product.

<<< §5. Some variations >>>
Finally, some modifications will be described.

<5-1. Modified Example of Forming Opening in Support>
Until now, the example which uses the flat support body 20 as an object sensor which concerns on this invention has been described. Of course, the support 20 does not necessarily have a flat plate shape and may have an arbitrary shape, but it is preferable to use the flat plate support 20 for mounting on an arbitrary apparatus. In particular, in the case of configuring a two-dimensional sensor, it is necessary to arrange a plurality of capacitive elements two-dimensionally. Therefore, it is desirable that the support 20 has a flat plate shape.

  As described above, the support 20 can be formed of a rigid substrate such as a glass epoxy substrate or a ceramic substrate, or can be formed of a flexible film such as a polyimide film or a PET film, or can be formed of a silicone rubber or the like. It can also be constituted by a sheet. In the case where the support body 20 is used for an application to be attached to a curved surface of an arbitrary shape such as a fingertip of a robot arm, it is preferable that the support body 20 has flexibility, so that the support body 20 made of a flexible film is used. do it. In this case, when mounted on a curved surface of an arbitrary shape, the detection surface S of the object sensor is not a flat surface but changes to the curved surface of the arbitrary shape.

  Even when a substrate having a certain degree of rigidity is used as a support, if openings are formed at several places, flexibility can be added. FIG. 23 (a) is a top view showing a modification in which an opening is formed in the embodiment shown in FIG. 22 (hatching is for clearly showing the electrode shape, not for showing a cross section). FIG. 23 (b) is a side sectional view showing a state in which this is cut at the position of the cutting line 23b-23b. The difference between the support 20 shown in FIG. 22 and the support 30 shown in FIG. 23 is that the latter is provided with openings U1 to U9 at a plurality of locations. Specifically, in the case of the support 30 made of this flat structure, an opening that penetrates the thickness of the structure is provided in a region where no capacitive element is formed, and the entire structure is deformed. It is configured to easily occur. For this reason, the entire structure is deformed, and is suitable for use on a curved surface having an arbitrary shape.

  Specifically, in the case of the illustrated example, the openings U1, U2, U4, and U5 are disposed between adjacent capacitive elements, and the openings U3, U6, and U7 to U9 are edges of the structure. It is arranged in the part. As described above, if the opening is arranged at a place avoiding the arrangement portion of the capacitive element, the detection operation by the capacitive element is not hindered. In the case of the illustrated example, the openings U1, U2, U4, U5 are square-shaped openings, but the other openings have various shapes. This is a convenience for showing variations in the shape of the opening, and in practice, all the openings may have the same shape. As shown in the illustrated variation, the opening may have any shape as long as it has an effect of adding flexibility to the support 30.

  When the disk-shaped center electrode Ec and the annular peripheral electrode Ep are used as in the illustrated embodiment, a gap is generated between the adjacent capacitive elements, so that the opening can be efficiently arranged in the gap portion. it can. Therefore, when the opening is formed in the support, it is convenient to form the capacitive element by the disc-shaped center electrode Ec and the annular peripheral electrode Ep.

  As shown in the side sectional view of FIG. 23 (b), in this example, the openings U1 to U9 penetrate not only the flat support 30 but also the first insulating layer 32 and the second insulating layer 33. It is the opening part which consists of a through-hole. When each insulating layer 32, 33 is made of a flexible material such as a resin, the opening does not necessarily have a through-hole structure that penetrates to each insulating layer 32, 33. In order to provide sufficient flexibility, it is preferable to provide an opening that penetrates the thickness of the structure including 32 and 33.

  Thus, the flat support 30 having openings at a plurality of locations eventually forms a sheet-like structure having a network structure and has sufficient flexibility. Therefore, it is possible to realize an object sensor suitable for use on a curved surface having an arbitrary shape such as a fingertip of a robot arm.

  Further, in the case of the conventional object sensor shown in FIG. 2, each of the elongated linear electrodes Ex and Ey plays a role of constituting a localized capacitance element, so that if the width is reduced, the detection sensitivity is lowered. However, in the case of the object sensor according to the present invention, the wiring layer connecting the adjacent capacitive elements only needs to be able to play a role as wiring, so that the width can be reduced to the minimum necessary. Therefore, when an application to be attached to a curved surface of an arbitrary shape is assumed, sufficient flexibility can be ensured by designing the width of the wiring layer as thin as possible.

<5-2. Modified example of electrode shape>
So far, an example has been described in which the capacitive element is configured using the disc-shaped center electrode Ec and the annular peripheral electrode Ep. However, in carrying out the present invention, the center electrode Ec is not necessarily a disc-shaped electrode. The peripheral electrode Ep is not necessarily an annular electrode. The center electrode Ec need only be an electrode having an arbitrary shape arranged at a predetermined detection point P, and the peripheral electrode Ep need only be an electrode arranged so as to surround the center electrode Ec.

  FIG. 24 is a plan view showing variations of the central electrode Ec and the peripheral electrode Ep used in the present invention. Here, the hatching in the figure is for clearly showing the electrode shape, not for showing the cross section.

  FIG. 24A shows an example in which a capacitive element is configured using the disc-shaped center electrode Ec and the annular peripheral electrode Ep described so far. Since the center electrode Ec and the peripheral electrode Ep are concentrically arranged so that the detection point P is the center point, the entire capacitive element forms a rotationally symmetric body. For this reason, even if the object M approaches from any direction around 360 ° around the detection point P, an equivalent change occurs in the capacitance value, and a more accurate detection operation can be expected. Moreover, also when forming the opening parts U1-U9 as shown in FIG. 23, it becomes easy to ensure an area | region required for opening part formation by using a circular electrode.

  Therefore, the inventor of the present application considers that the electrode shape shown in FIG. 24 (a) is most preferable in carrying out the present invention. Further, according to an experiment conducted by the inventor of the present application, a setting in which the total area S (Ec) of the central electrode Ec is equal to the total area S (Ep) of the peripheral electrode Ep (S (Ec) = S (Ep)) ), The detection sensitivity tended to improve. Therefore, in actuality, the electrode configuration (S (Ec) = S (Ep)) shown in FIG. 24A is more than the electrode configuration shown in FIG. 6A (S (Ec) <S (Ep)). It can be said that it is preferable.

  Of course, in principle, as shown in FIG. 24B, a capacitive element having a structure in which a rectangular frame-shaped peripheral electrode Ep surrounds the rectangular central electrode Ec may be formed. As shown in FIG. 24 (c), a capacitive element having a structure in which an annular peripheral electrode Ep surrounds a rectangular central electrode Ec may be formed. In addition, as shown in FIG. 24 (d), a capacitive element having a structure in which the annular central electrode Ec surrounds the annular central electrode Ep may be formed.

  FIG. 24 (e) shows a star-shaped central electrode Ec whose outer contour is composed of a large number of polygonal lines (zigzag lines), a star shape whose inner contour is composed of a large number of polygonal lines (zigzag lines), and whose outer contour is composed of a circle. This is an example in which a capacitive element having a structure surrounded by a special-shaped peripheral electrode Ep is formed. According to the experiments conducted by the inventors of the present application, the outer contour of the center electrode Ec is configured by a large number of broken lines (zigzag lines), and the inner contour of the peripheral electrode Ep is configured by a large number of bent lines (zigzag lines) along this. In this case, the detection sensitivity tends to be improved as compared with the case where each contour is formed by a circle.

  Although the detailed analysis about the reason is not made at present, the inventor of the present application increases the total length of the outer contour line of the center electrode Ec and the inner contour line of the surrounding electrode Ep opposed thereto. This is considered to be because the influence of an object existing in the vicinity on the capacitance value increases for some reason.

  FIG. 24 (f) is an example in which a notch L is provided in a part of the peripheral electrode Ep in FIG. 24 (a). The peripheral electrode Ep in the present invention needs to have a shape surrounding the central electrode Ec, but it is not necessary to surround all 360 ° around the central electrode Ec. In other words, the peripheral electrode Ep does not necessarily have a complete annular structure, and the cutout portion L may be formed in part. In the example shown in FIG. 24 (f), the central electrode Ec is a disc-shaped electrode disposed around the detection point P, and the peripheral electrode Ep is disposed so as to surround the central electrode Ec. This is an example of an incomplete annular electrode having a notch L.

  Of course, as shown in FIG. 24 (f), if the notch L is formed in a part of the peripheral electrode Ep, the capacitive element is not a perfect rotationally symmetric body. Even when the object M approaches from any direction, the characteristic that an equivalent fluctuation occurs in the capacitance value is lost. Moreover, since the capacitance value is reduced by providing the notch L, the detection sensitivity is slightly lowered. However, there is an advantage that wiring to the center electrode Ec becomes possible by using the notch L.

  FIG. 25 is a top view showing a modified example in which wiring is performed using such merits. Also in FIG. 25, hatching is for clearly showing the electrode shape, and is not for showing a cross section. This modification is an example of a one-dimensional object sensor in which three sets of capacitive elements C1 to C3 are arranged on the upper surface of the plate-like support 20 along the X-axis direction. As illustrated, the three sets of capacitive elements C1 to C3 are arranged at the positions of detection points P1 to P3 defined on the X axis.

  Here, paying attention to the wiring for each electrode, the peripheral electrodes Ep1, Ep2, Ep3 are connected to the terminal Tx by the lateral wiring layers Wx1, Wx2, Wx3, and the central electrodes Ec1, Ec2, Ec3 are the vertical wirings. The layers Wy1 to Wy3 are connected to the terminals Ty1 to Ty3. In addition, since the vertical wiring layers Wy1 to Wy3 pass through the notches provided in the peripheral electrodes Ep1, Ep2, and Ep3, it is not necessary to three-dimensionally intersect the peripheral electrodes Ep1, Ep2, and Ep3.

  Therefore, in the case of the modification shown in FIG. 25, the center electrodes Ec1 to Ec3, the peripheral electrodes Ep1 to Ep3, the lateral wiring layers Wx1, Wx2, Wx3, the vertical wiring layers Wy1 to Wy3, the terminals Tx, Ty1 to Ty3 (FIG. All of the constituent elements shown by hatching can be formed on the same detection surface S. In other words, in the case of the modification shown in FIG. 25, it is not necessary to form the two insulating layers 22 and 23 as shown in FIGS. 17 and 22, but a single layer as shown in FIG. It is sufficient if the insulating layer 21 is formed. In this way, if the notch L is formed in the peripheral electrode Ep and the wiring to the center electrode Ec is performed through the notch L, the configuration of the insulating layer can be made only one layer. Cost can be reduced.

<5-3. Modified example of insulating layer>
In the examples shown in FIG. 17B and FIG. 22B, the structure in which the first insulating layer 22 and the second insulating layer 23 are laminated on the upper surface of the support 20 is shown. It is not necessary to divide into a two-layer structure, and a single-layer structure in which both are fused may be used. However, in consideration of the actual manufacturing process, a necessary conductive layer (electrode or wiring layer) is formed on the upper surface of the support 20, and the first insulating layer 22 made of resin or the like is formed so as to cover the conductive layer. A process of forming a necessary conductive layer (electrode or wiring layer) on the upper surface and further forming a second insulating layer 23 made of resin or the like so as to cover it is preferable. Through such a process, an insulating layer having a two-layer structure as shown is formed.

  Although it is possible in principle to operate without the second insulating layer 23, if the electrode is exposed on the upper surface, a short circuit accident due to contact with the object may occur. In addition, since the surface may be corroded by oxidation or the like, in practice, the surface is covered with some protective layer (in the above example, the second insulating layer 23) so that the electrode is not exposed. Is preferred.

  In short, each electrode used in the object sensor according to the present invention is formed directly on the surface of the support 20 or indirectly through another insulating layer, and the upper surface of each electrode is covered with the insulating layer. It is preferable to do so. The insulating layer functions as a protective layer, can protect each electrode from corrosion, and can prevent an external conductor from coming into direct contact with each electrode and causing an electrical short circuit.

DESCRIPTION OF SYMBOLS 10: Support body 11: 1st insulating layer 12: 2nd insulating layer 20: Support body 21: Insulating layer 22: 1st insulating layer 23: 2nd insulating layer 30: Support body 32: 1st insulation Layer 33: Second insulating layer 50: Position detecting means 51: Capacitance value measuring unit 52: Position specifying unit A, A1 to A9: Detection region Bt: Cut plane C, C1 to C9: Capacitance element / capacitance value Cij : Capacitance element / capacitance value C (1,1) to C (9,9): Cell indicating capacitance element / Capacitance value C0: Existing capacitance value Cmax: Maximum capacitance value Cleft, Cright: Left and right Additional capacitance Ct: Capacitance value threshold value E1, E2: Electrodes Ec, Ec1 to Ec9: Center electrode Ep, Ep1 to Ep9: Peripheral electrode Ep (L): Left side portion Ep (R) of the peripheral electrode: Peripheral electrode Right side portions Ex, Ex1 to Exi: row direction electrodes Ey, Ey1 to Eyj: column direction electrodes G: travel length Paths G1 to G3: Graph Gxy: Three-dimensional graph g: Center of gravity H of significant region St: Wiring contact hole h: Height L: Notch M: Object m: Measurement circuit P, P1 to P9: Detection point Pij: Detection points Q, Q1 to Q3: Object position S: Detection surface St: Significant region SWx1 to SWx3: Changeover switch SWy1 to SWy4: Changeover switch T1, T2: Terminal Ta, Tb: Terminal Tx, Tx1 to Tx3: Terminals Ty1 to Ty3: Terminals U1 to U9: Openings W7 to W9: Interlayer wiring layers Wx, Wx1 to Wx9: Horizontal wiring layers Wy, Wy1 to Wy9: Vertical wiring layers Wy10 to Wy30: Vertical wiring layers X: XYZ The coordinate axis Xg of the three-dimensional orthogonal coordinate system: the X coordinate value of the center of gravity point g Y: the coordinate axis Yg of the three-dimensional orthogonal coordinate system Yg: the Y coordinate value of the center of gravity point g Z: the coordinate axis of the XYZ three-dimensional orthogonal coordinate system ξ: on the X axis of Location ξ1~ξ3: capacitance value

Claims (5)

An object sensor for detecting the position of an object existing in the vicinity,
A support that supports a predetermined detection surface;
A total of N sets of capacitive elements respectively arranged in the vicinity of a plurality of N detection points defined on the detection surface;
Position detecting means for detecting the position of the object based on the capacitance values of the N sets of capacitive elements;
With
Each of the capacitive elements has a central electrode disposed at the detection point and a peripheral electrode disposed so as to surround the central electrode, and the central electrode and the peripheral electrode are supported by the support body. Has been
The position detecting means includes a capacitance value measuring unit that measures a capacitance value between the central electrode and the surrounding electrode for each capacitance element, and the object based on each measured capacitance value. A position specifying part for specifying the position of
The support is made of a flat structure, and an opening that penetrates the thickness of the structure is provided in a region of the structure where no capacitive element is formed, and the entire structure is deformed. An object sensor configured as described above. The object sensor according to claim 1,
N detection points are defined side by side on a predetermined arrangement axis on the detection plane, and N sets of capacitive elements constitute a one-dimensional array along the arrangement axis,
An object sensor, wherein a position specifying unit specifies a position in a one-dimensional direction along the arrangement axis for an object. The object sensor according to claim 1,
Detection points are defined at the positions of each grid point of the two-dimensional grid placed on the detection surface,
N sets of capacitive elements constitute a two-dimensional array corresponding to the two-dimensional lattice,
A position specifying unit specifies a position in a two-dimensional direction corresponding to the two-dimensional grid for an object. The object sensor according to any one of claims 1 to 3 ,
A first insulating layer is formed on the upper surface of the support, and a second insulating layer is formed on the upper surface of the first insulating layer. Of the first insulating layer and the second insulating layer, When one is called the main insulation layer and the other is the sub insulation layer,
A central electrode, a peripheral electrode, and a peripheral electrode wiring layer for electrically connecting the peripheral electrode to the capacitance measuring unit are embedded in the main insulating layer,
A central electrode wiring layer for electrically connecting the central electrode to the capacitance value measuring unit is embedded in the sub-insulating layer,
An object sensor, wherein an interlayer wiring layer penetrating a boundary surface between the main insulating layer and the sub insulating layer is formed between a central electrode and a central electrode wiring layer. The object sensor according to any one of claims 1 to 3 ,
A first insulating layer is formed on the upper surface of the support, and a second insulating layer is formed on the upper surface of the first insulating layer. Of the first insulating layer and the second insulating layer, When one is called the center electrode formation layer and the other is the surrounding electrode formation layer,
A central electrode and a central electrode wiring layer for electrically connecting the central electrode to the capacitance value measuring unit are embedded in the central electrode forming layer,
An object sensor, wherein a peripheral electrode and a peripheral electrode wiring layer for electrically connecting the peripheral electrode to a capacitance value measuring unit are embedded in the peripheral electrode forming layer.

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