Capacitive sensor, detection circuit and detection method

Abstract

The objective of this invention is to accurately determine the number of objects to be detected on a capacitive sensor. As a solution, the invention includes a first insulating layer; a detection electrode extending along a first direction on the surface of the first insulating layer; a side shielding electrode disposed parallel to the detection electrode on the surface of the first insulating layer; a side grounding electrode disposed parallel to the detection electrode and the side shielding electrode on the surface of the first insulating layer and connected to a ground potential; and a first back shielding electrode disposed on the other side of the first insulating layer and facing the detection electrode through the first insulating layer. The detection electrode is subjected to a first AC driving voltage, and the side shielding electrode and the first back shielding electrode are subjected to a second AC driving voltage having the same frequency and phase as the first AC driving voltage. The detection electrode has a plurality of monolithic electrodes spaced apart and arranged parallel along the first direction, and the side shielding electrodes are arranged parallel between the detection electrode and the side grounding electrode.

Description

[Technical Field]

[0001] This invention relates to a capacitance sensor, a detection circuit, and a detection method. [Previous Technology]

[0002] Patent Document 1 below discloses a technique in which a capacitive proximity sensor comprising a sensor electrode, an auxiliary electrode disposed near the sensor electrode, and a shielding electrode disposed on the back side of the sensor electrode applies the same potential to the auxiliary electrode and the shielding electrode as to the sensor electrode. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2009 / 044920 [Summary of the Invention]

[0004] [Problem to be Solved by the Invention] However, in the technology of Patent Document 1 above, although it is possible to detect the increase or decrease of the number of detected objects mounted on the capacitive proximity sensor, since the capacitance change of each detected object is not necessarily constant, it is not possible to accurately determine the number of detected objects mounted on the capacitive proximity sensor. [Means for Solving the Problem]

[0005] Regarding one embodiment of the capacitive sensor, it comprises a first insulating layer, a detection electrode extending along a first direction on the surface of the first insulating layer, a side shielding electrode disposed side-by-side with the detection electrode on the surface of the first insulating layer, a side grounding electrode disposed side-by-side with the detection electrode and the side shielding electrode on the surface of the first insulating layer and connected to a ground potential, and a first back shielding electrode disposed on another side of the first insulating layer and facing the detection electrode through the first insulating layer; a first AC driving voltage is applied to the detection electrode, and a second AC driving voltage having the same frequency and phase as the first AC driving voltage is applied to the side shielding electrode and the first back shielding electrode; the detection electrode has a plurality of single electrodes disposed side-by-side at intervals in the first direction, and the side shielding electrode is disposed side-by-side between the detection electrode and the side grounding electrode. [Effects of the Invention]

[0006] According to one embodiment of the capacitance type sensor, the number of detected objects placed on the capacitance type sensor can be specified with high precision.

Implementation Method

[0008] Hereinafter, an embodiment will be described with reference to the drawings. Furthermore, for convenience, in the following description, the X-axis direction will be defined as the left-right direction, the Y-axis direction as the front-back direction, and the Z-axis direction as the up-down direction. However, the positive X-axis direction will be defined as the right direction, the positive Y-axis direction as the front direction, and the positive Z-axis direction as the up direction. These terms indicate the relative positional relationships within the device and do not limit the device's installation or operating direction. Devices with the same relative positional relationships within the device, regardless of their installation or operating direction, are included within the scope of the present invention.

[0009] (Configuration of Capacitive Sensor 100) Figure 1 is a plan view of a capacitive sensor 100 according to one embodiment. Figure 2 is a cross-sectional view of a capacitive sensor 100 according to one embodiment along section AA (see Figure 1). Figure 3 is a cross-sectional view of a capacitive sensor 100 according to one embodiment along section BB (see Figure 1). Figure 4 is an exploded plan view of a capacitive sensor 100 according to one embodiment. Furthermore, Figure 4 shows a plan view from above (positive Z-axis direction) of the electrode layer L1, bridging wiring layer L2, wiring layer L3, and back cover shielding layer L4 of each capacitive sensor 100.

[0010] As shown in Figures 1 to 4, a capacitance sensor 100 in one embodiment includes a detection circuit 120, a first insulating layer 101, two detection electrodes 102, two side shielding electrodes 103, a side grounding electrode 104, and a first back shielding electrode 106.

[0011] As shown in Figures 1 and 4, the detection circuit 120 is disposed in the electrode layer L1 on the surface 101A side of the first insulating layer 101, and is positioned at the end of the surface 101A (positive Y-axis side) of the first insulating layer 101. The detection circuit 120 is connected to each of the plurality of monolithic electrodes 102A of the detection electrode 102 through the wiring group 110. The detection circuit 120 can detect the capacitance change of each of the plurality of monolithic electrodes 102A by applying a first AC driving voltage V1 to each of the plurality of monolithic electrodes 102A through the wiring group 110. In addition, the detection circuit 120 can apply a second AC driving voltage V2 with the same frequency and phase as the first AC driving voltage V1 to each of the side shielding electrode 103, the first back shielding electrode 106, the second back shielding electrode 109, and the third back shielding electrode 112.

[0012] However, in this embodiment, the detection circuit 120 is integrally formed with the capacitance sensor 100 (surface 101A of the first insulating layer 101), but it is not limited to this. For example, the detection circuit 120 and the capacitance sensor 100 may be separately formed and electrically connected to each other through wiring components (e.g., cables, FPCs, etc.). Furthermore, the detection circuit 120 may also be provided on the back side of the capacitance sensor 100.

[0013] The first insulating layer 101 is a layer formed of an insulating material. The first insulating layer 101 supports each electrode (detection electrode 102, side grounding electrode 104, side shielding electrode 103, and first back shielding electrode 106). Viewed from above (positive Z-axis direction), the first insulating layer 101 has a certain width in the left-right direction (X-axis direction) and a certain length in the front-back direction (Y-axis direction), and is rectangular in shape. The first insulating layer 101 can be formed, for example, using insulating resins such as PET (polyethylene terephthalate), PMMA (polymethyl methacrylate), glass, glass epoxy resin, glass polyimide resin, paper epoxy resin, paper phenolic resin, etc.

[0014] The side grounding electrode 104 is disposed in the electrode layer L1 on the surface 101A side of the first insulating layer 101, and is located at the center of the surface 101A of the first insulating layer 101 in the left-right direction (X-axis direction). It is a thin-film electrode made of conductive materials such as metal, inorganic conductive oxide, and conductive resin. The side grounding electrode 104 has a strip-shaped extension in a straight line in the front-back direction (Y-axis direction). The side grounding electrode 104 is disposed side by side on the surface 101A of the first insulating layer 101 between the two detection electrodes 102. The side grounding electrode 104 is connected to the grounding potential.

[0015] Two detection electrodes 102 are disposed in the electrode layer L1 on the surface 101A side of the first insulating layer 101, and are thin-film electrodes made of conductive materials such as metal, inorganic conductive oxide, and conductive resin. Each of the two detection electrodes 102 has an overall shape of being a strip extending linearly in the front-back direction (Y-axis direction). The two detection electrodes 102 are disposed side by side on the surface 101A of the first insulating layer 101, on the outer sides of the side grounding electrode 104 in the left-right direction (X-axis direction). Each of the two detection electrodes 102 is driven by applying a first AC driving voltage V1 by the first driving / detection circuit 121A of the detection circuit 120.

[0016] Regarding one embodiment of the capacitive sensor 100, when the placement state of the detected object 20 on the capacitive sensor 100 changes, the capacitance (Crg+Crg') of the detected object 20 detected by the detection electrode 102 (see Figure 5) will change. Therefore, regarding one embodiment of the detection circuit 120, it can determine the placement state of the detected object 20 on the capacitive sensor 100 (whether the detected object 20 exists, the number of detected objects 20, etc.) based on the capacitance (Crg+Crg') of the detected object 20 detected by the detection electrode 102.

[0017] In particular, regarding one embodiment of the capacitive sensor 100, a side grounding electrode 104 is provided on the surface 101A of the first insulating layer 101, arranged side-by-side with the detection electrode 102. Therefore, in this embodiment of the capacitive sensor 100, when the detected object 20 is present on the capacitive sensor 100, a capacitance Crg is generated between the detection electrode 102 and the detected object 20, and a capacitance Crg' is generated between the detected object 20 and the side grounding electrode 104 (see Figure 5). Therefore, in this embodiment of the capacitive sensor 100, when the detected object 20 is present on the capacitive sensor 100, the capacitance of the detected object 20 detected by the detection electrode 102 is amplified to the sum of the capacitance Crg and the capacitance Crg', thereby improving the detection accuracy of the detection electrode 102 for the detected object 20.

[0018] Two side-shielding electrodes 103 are disposed in the electrode layer L1 on the surface 101A side of the first insulating layer 101, and are thin-film electrodes made of conductive materials such as metal, inorganic conductive oxide, and conductive resin. The two side-shielding electrodes 103 are disposed side by side on the surface 101A of the first insulating layer 101, on both sides of the side grounding electrode 104 in the left-right direction (X-axis direction). Each of the two side-shielding electrodes 103, when viewed from above (positive Z-axis direction), has a rectangular frame shape surrounding the detection electrode 102. The side-shielding electrodes 103 are driven by applying a second AC driving voltage V2 by the second driving circuit 121B of the detection circuit 120. However, in this embodiment, as an example, two side shielding electrodes 103 are integrally formed on the surface 101A of the first insulating layer 101 (i.e., connected on the surface 101A), but the two side shielding electrodes 103 can also be formed separately, and the two side shielding electrodes 103 can be driven individually and simultaneously by the second driving circuit 121B of the detection circuit 120.

[0019] As shown in Figures 1 to 3, the side shielding electrode 103 has a pair of straight sections 103A extending in the front-back direction (X-axis direction) and parallel to each other, and the detection electrode 102 is disposed between the pair of straight sections 103A.

[0020] One of the pair of linear portions 103A is positioned between the detection electrode 102 and the side grounding electrode 104, thereby reducing the parasitic capacitance between them. Therefore, in one embodiment of the capacitive sensor 100, the detection object 20 with low conductivity or capacitance can be detected with higher sensitivity.

[0021] However, providing a pair of left and right straight sections 103A is synonymous with providing a pair of left and right two side shielding electrodes 103. That is, providing a detection electrode 102 between a pair of left and right straight sections 103A is synonymous with providing a detection electrode 102 between a pair of left and right two side shielding electrodes 103.

[0022] The other linear portion 103A of the pair of left and right linear portions 103A is positioned on the outside (positive X-axis side) of the detection electrode 102, which prevents external noise from the outside of the detection electrode 102 from flowing into the detection electrode 102. Therefore, with respect to one embodiment of the capacitive sensor 100, the tolerance to external noise can be improved, and the stability of the high SN ratio of the detected signal can be improved.

[0023] The first back-side shielding electrode 106 is disposed in the bridging wiring layer L2 on the back-side 101B side of the first insulating layer 101, and is disposed on the back-side 101B of the first insulating layer 101. It is a thin-film electrode made of conductive materials such as metal, inorganic conductive oxide, and conductive resin. The first back-side shielding electrode 106 is rectangular in shape with the front-to-back direction (Y-axis direction) as the long side when viewed from above (positive Z-axis direction), covering the entire back-side 101B of the first insulating layer 101. The first back-side shielding electrode 106 is disposed opposite to the detection electrode 102 through the first insulating layer 101. The first back-side shielding electrode 106 is driven by the second driving circuit 121B of the detection circuit 120 applying a second AC driving voltage V2. In the center of the first back shielding electrode 106 in the left-right direction (X-axis direction), a rectangular opening 106A extending in the front-back direction (Y-axis direction) is formed when viewed from above (positive Z-axis direction).

[0024] Regarding one embodiment of the capacitive sensor 100, by having a first back-side shielding electrode 106, the parasitic capacitance Crs(c) of the first back-side shielding electrode 106 (see FIG5) can be used to reduce the parasitic capacitance generated between the detection electrode 102 and the side grounding electrode 104 and the grounding potential. Therefore, when a detected object 20 is present in the capacitive sensor 100, the capacitance detected by the detection electrode 102 will exclude the parasitic capacitance Crg1, and will essentially only be the capacitance of the detected object 20 (Crg+Crg'). Therefore, with one embodiment of the capacitive sensor 100, the detection accuracy of the detection electrode 102 for the detected object 20 can be improved.

[0025] Here, as shown in FIG1, each of the two detection electrodes 102 provided on the surface 101A of the first insulating layer 101 has a plurality of monolithic electrodes 102A arranged side by side with a gap in the front-back direction (Y-axis direction) (an example of the "first direction"). That is, for a capacitance sensor 100 of an embodiment, a plurality of monolithic electrodes 102A (hereinafter referred to as "monolithic electrode pairs") are arranged side by side with a gap in the front-back direction (Y-axis direction) (an example of the "first direction").

[0026] In each single electrode pair, one single electrode 102A is connected to the detection circuit 120 through the wiring group 110 described later, and is driven by the first drive / detection circuit 121A of the detection circuit 120 applying a first AC drive voltage V1.

[0027] In each monolithic electrode pair, the other monolithic electrode 102A is electrically connected to the first monolithic electrode 102A through a connecting member 102B disposed in the opening 106A of the first back-side shielding electrode 106 in the bridging wiring layer L2. In this way, the other monolithic electrode 102A is integrated with the first monolithic electrode 102A and is driven simultaneously with the first monolithic electrode 102A.

[0028] The connecting member 102B extends in the bridging wiring layer L2 along the left-right direction (X-axis direction) and is a thin-film electrode made of conductive materials such as metal, inorganic conductive oxide, and conductive resin. As shown in Figure 2, the left end (negative X-axis side) of the connecting member 102B is connected to the second through hole 115 of the first insulating layer 101 through the monolithic electrode 102A passing through the left end (negative X-axis side); the right end (positive X-axis side) is connected to the second through hole 115 of the first insulating layer 101 through the monolithic electrode 102A passing through the right end (positive X-axis side).

[0029] However, since the connecting member 102B is provided for each single electrode pair, as shown in FIG4, in the bridging wiring layer L2, in the opening 106A of the first back-side shielding electrode 106, the same number of connecting members 102B as the number of single electrode pairs are arranged side by side in the front-back direction (Y-axis direction).

[0030] Furthermore, in this embodiment, as a preferred example, the connecting member 102B is disposed in the bridging wiring layer L2, but it is not limited thereto. The connecting member 102B may also be disposed in the lower layer of the bridging wiring layer L2. For example, the connecting member 102B may be disposed in the wiring layer L3, and the left and right pairs of monolithic electrodes 102A may be connected through the connecting member 102B and the second through hole 115 penetrating the first insulating layer 101, the first back shielding electrode 106 and the second insulating layer 107.

[0031] As described above, in one embodiment of the capacitance sensor 100, the detection electrode 102 has a plurality of single electrode pairs arranged side by side in the front-back direction (Y-axis direction), and each of the plurality of single electrode pairs can be individually driven by the detection circuit 120. Therefore, in one embodiment of the capacitance sensor 100, when the placement state of the detected object 20 changes, when viewed from above (positive Z-axis direction), the capacitance detection value of a portion of the single electrode pairs arranged at the position overlapping with the detected object 20 will change significantly. This allows for high-precision detection of the position and range of change in the placement state of the object 20 in the specific front-back direction (Y-axis direction).

[0032] Furthermore, regarding one embodiment of the capacitance sensor 100, the number B of monolithic electrodes 102A required to detect one object 20 is predetermined, and the number of objects 20 placed on the capacitance sensor 100 can be easily calculated by counting the number A of monolithic electrodes 102A that change in capacitance according to the formula (A÷B).

[0033] Furthermore, regarding one embodiment of the capacitance sensor 100, even if the plurality of detected objects 20 are arranged far apart in the front-back direction (Y-axis direction), when viewed from above (positive Z-axis direction), the capacitance detection value of the single electrode pair provided at the overlapping position with each detected object 20 will change significantly, thereby allowing for individual and high-precision identification of the placement position of each detected object 20.

[0034] Furthermore, as shown in Figures 2 and 3, a capacitance-type sensor 100 in one embodiment includes a second insulating layer 107 disposed on the back side of the first back shielding electrode 106 (i.e., the bridging wiring layer L2), a wiring layer L3 disposed on the back side of the second insulating layer 107, and a third insulating layer 108 disposed on the back side of the wiring layer L3.

[0035] The second insulating layer 107 and the third insulating layer 108 are the same as the first insulating layer 101, and are layers formed of insulating material.

[0036] As shown in Figures 2 to 4, the wiring layer L3 has a second back shielding electrode 109 covering the back side of the second insulation layer 107, and a wiring group 110 disposed in the notch 109A formed by the second back shielding electrode 109.

[0037] The second back-side shielding electrode 109 is the same as the first back-side shielding electrode 106, and is a thin-film electrode made of conductive materials such as metal, inorganic conductive oxide, and conductive resin. The second back-side shielding electrode 109, when viewed from above, has a rectangular shape with the long side of the front-to-back direction (Y-axis direction) set to the entire back side of the second insulating layer 107. The second back-side shielding electrode 109, like the first back-side shielding electrode 106, is driven by the application of a second AC driving voltage V2 by the second driving circuit 121B of the detection circuit 120.

[0038] The wiring group 110 is composed of a plurality of wirings 110A for each individual electrode 102A. The wiring group 110 is provided in the notch 109A of the second back shielding electrode 109, extending in the front-back direction (Y-axis direction). One end of the wiring group 110 (the end on the positive side of the Y-axis) is connected to the detection circuit 120, and the other end (the end on the negative side of the Y-axis) is connected to each of the plurality of individual electrodes 102A through the first through hole 111 penetrating the first insulating layer 101, the first back shielding electrode 106, and the second insulating layer 107.

[0039] As described above, in one embodiment of the capacitive sensor 100, a wiring group 110 for applying a first AC driving voltage V1 to a plurality of monolithic electrodes 102A is disposed in the wiring layer L3 on the back side of the first back shielding electrode 106, and is connected to each of the plurality of monolithic electrodes 102A through the first through hole 111. Therefore, the capacitive coupling and parasitic capacitance between the wiring group 110 and the detected object 20 can be reduced, and the SN ratio of the detected signal can be improved.

[0040] Furthermore, regarding one embodiment of the capacitive sensor 100, the wiring group 110 is disposed within the notch 109A of the second back shielding electrode 109 (that is, the area surrounded by the second back shielding electrode 109), and by applying the second AC drive voltage V2 to the second back shielding electrode 109, the parasitic capacitance of the wiring group 110 can be reduced and external noise can be prevented from being superimposed on the wiring group 110, thereby further improving the detection signal SN ratio.

[0041] However, in the examples shown in Figures 2 to 4, the second back-side shielding electrode 109 has two notches 109A on the left and right sides, and the wiring group 110 is disposed in each of the two notches 109A. This is because in this embodiment, the number of monolithic electrodes 102A is relatively large, and the number of wirings 110A is also relatively large. In order to accommodate this large number of wirings 110A, two notches 109A are provided.

[0042] As shown in FIG. 4, each of the two notches 109A, viewed from above (positive Z-axis direction), has a shape that is cut off along the overall shape of the wiring group 110. The wiring group 110 in the notch 109A on the left (negative X-axis side) is used to connect the single electrode 102A on the left (negative X-axis side) of a portion of the plurality of single electrode pairs to the detection circuit 120, and a plurality of wirings 110A extending in the front-back direction (Y-axis direction) are arranged side by side. The wiring group 110 in the notch 109A on the right (positive X-axis side) is used to connect the single electrode 102A on the right (positive X-axis side) of the remaining portion of the plurality of single electrode pairs to the detection circuit 120, and a plurality of wirings 110A extending in the front-back direction (Y-axis direction) are arranged side by side.

[0043] Furthermore, as shown in FIG4, the plurality of wirings 110A in the wiring group 110 have different lengths in the front-to-back direction (Y-axis direction) because each of them has the length of a single electrode 102A to which it is connected. In the example shown in FIG4, each wiring group 110 has a plurality of wirings 110A of different lengths arranged side by side, such that the length of the wirings 110A gradually decreases towards the inside of the capacitive sensor 100 (that is, towards the side grounding electrode 104).

[0044] Furthermore, as shown in Figures 2 and 3, in one embodiment of the capacitive sensor 100, a third back-shielding electrode 112 is provided in a back-shielding layer L4 on the back side of the third insulating layer 108. The third back-shielding electrode 112 is the same as the first back-shielding electrode 106 and the second back-shielding electrode 109, and is a thin-film electrode made of conductive materials such as metal, inorganic conductive oxide, or conductive resin. Viewed from above, the third back-shielding electrode 112 has a rectangular shape with the longitudinal direction (Y-axis direction) as the long side, covering the entire back side of the third insulating layer 108. Like the first back-shielding electrode 106 and the second back-shielding electrode 109, the third back-shielding electrode 112 is driven by a second AC driving voltage V2 applied by the second driving circuit 121B of the detection circuit 120.

[0045] As described above, in one embodiment of the capacitive sensor 100, a third back shielding electrode 112 is provided through the third insulating layer 108 on the back side. By applying a second AC driving voltage V2 to the third back shielding electrode 112, the parasitic capacitance of the wiring group 110 can be reduced and external noise can be prevented from being superimposed on the wiring group 110. Therefore, the signal-to-noise ratio of the detected signal can be further improved.

[0046] However, as shown in Figures 2 and 3, in one embodiment of the capacitance sensor 100, on the back side of the third back shielding electrode 112, there is a back grounding electrode 113 that is spaced apart from and opposite to the third back shielding electrode 112 and connected to the ground potential.

[0047] Accordingly, the capacitive sensor 100 of one embodiment can effectively attenuate external electromagnetic noise from the back side of the third back shielding electrode 112 and prevent noise from flowing into the detection electrode 102, thereby improving the high SN ratio stability of the detected signal.

[0048] Furthermore, regarding one embodiment of the capacitance sensor 100, since the left and right pairs of monolithic electrodes 102A are connected through the connecting member 102B provided in the bridging wiring layer L2 (the empty space 106A of the first back shielding electrode 106), there is no need to provide a separate wiring member for connecting the left and right pairs of monolithic electrodes 102A, and the capacitance sensor 100 can be miniaturized.

[0049] Furthermore, as shown in Figures 2 and 3, the capacitive sensor 100 in one embodiment further includes a cover plate 114. The cover plate 114 is disposed at the top of the capacitive sensor 100 and is an insulating member covering the surface 101A of the first insulating layer 101 and each electrode (detection electrode 102, side shielding electrode 103, and side grounding electrode 104). The cover plate 114 covers the entire surface 101A of the first insulating layer 101 and, when viewed from above (positive Z-axis direction), has the same shape as the surface 101A of the first insulating layer 101 (i.e., a rectangular shape). The cover plate 114 can be made of, for example, photosensitive photoresist such as PET (polyethylene terephthalate), PMMA (polymethyl methacrylate), phenolic varnish resin, solder resist, or glass material.

[0050] (Circuit Model of Capacitive Sensor 100) Figure 5 is a circuit model diagram of an embodiment of the capacitive sensor 100 (when the object 20 is detected to be present on the capacitive sensor 100). Here, approximately half of the right side (positive X-axis direction side) including the side ground electrode 104 is shown schematically with respect to the AA cross-sectional view 2 of Figure 1.

[0051] As shown in FIG5, the detection circuit 120 of the capacitance sensor 100 includes a capacitance detection unit 121, a processing unit 122 and an I / F (interface) 124.

[0052] The capacitance detection unit 121 is electrically connected to the detection electrode 102, the plurality of wirings 110A, the side shielding electrode 103, and the third back shielding electrode 112. The capacitance detection unit 121 has a first drive / detection circuit 121A and a second drive circuit 121B.

[0053] The first drive and detection circuit 121A generates a first AC drive voltage V1 and applies the first AC drive voltage V1 to the detection electrode 102 (that is, each of the plurality of single-piece electrodes 102A) through a plurality of wirings 110A. Furthermore, the first drive and detection circuit 121A detects the change Ie of the current Is flowing through the detection electrode 102 as a change in the capacitance in the detection electrode 102, and outputs a detection signal Ds based on the change Ie of the current Is.

[0054] The second driving circuit 121B generates a second AC driving voltage V2 with the same frequency and phase as the first AC driving voltage V1, and applies the second AC driving voltage V2 to the side shielding electrode 103 and the third back shielding electrode 112. Thereby, the second driving circuit 121B drives the side shielding electrode 103 and the third back shielding electrode 112, and also drives the first back shielding electrode 106 electrically connected to the side shielding electrode 103, and the second back shielding electrode 109 electrically connected to the third back shielding electrode 112.

[0055] The processing unit 122 performs various specific processes based on the detection signal Ds output from the capacitance detection unit 121. For example, based on the detection signal Ds, the processing unit 122 performs specific processes such as determining whether a detected object 20 exists on the capacitance sensor 100 and determining the number of detected objects 20 present on the capacitance sensor 100. For example, the processing unit 122 includes a processor (e.g., a CPU (Central Processing Unit)) and memory (e.g., RAM (Random Access Memory)), and executes various specific processes by executing programs stored in the memory through the processor. As the processing unit 122, for example, an IC (Integrated Circuit) is used.

[0056] I / F124 outputs the data of the result of the specific processing performed by the processing unit 122 (e.g., whether the object 20 is detected on the capacitance sensor 100, the number of the detected object 20 on the capacitance sensor 100, etc.) to other devices that use the data.

[0057] Furthermore, as shown in FIG5, the following parasitic capacitance is generated in one embodiment of the capacitive sensor 100.

[0058] • Parasitic capacitance between side grounding electrode 104 and connecting member 102B: Crgl(a) • Parasitic capacitance between side grounding electrode 104 and side shielding electrode 103: Csg(a) • Parasitic capacitance between side shielding electrode 103 and connecting member 102B: Crs(a) • Parasitic capacitance between detection electrode 102 and side shielding electrode 103: Crs(b) • Parasitic capacitance between detection electrode 102 and first back shielding electrode 106: Crs(c) • Parasitic capacitance between connecting member 102B and second back shielding electrode 109: Crs(d) • Parasitic capacitance between third back shielding electrode 112 and back grounding electrode 113: Csg(b) • Parasitic capacitance between wiring 110A and first back shielding electrode 106: Crs'(a) Parasitic capacitance between wiring 110A and the second back-side shielding electrode 109: Crs'(b) • Parasitic capacitance between wiring 110A and the third back-side shielding electrode 112: Crs'(c)

[0059] As shown in FIG. 5, in one embodiment of the capacitive sensor 100, the periphery (above, below, and sides) of each wiring 110A is protected by a first back-side shielding electrode 106, a second back-side shielding electrode 109, and a third back-side shielding electrode 112. Therefore, in one embodiment of the capacitive sensor 100, the parasitic capacitance of each wiring 110A can be reduced, and capacitive coupling between each wiring 110A and the detection electrode 102 can be prevented, thereby improving the detection signal-to-sense ratio.

[0060] (Example of circuit configuration of capacitance detection unit 121) FIG6 is a diagram showing an example of the circuit configuration of capacitance detection unit 121 provided in a capacitance type sensor 100 according to an embodiment. For example, as shown in FIG6, capacitance detection unit 121 includes a first drive / detection circuit 121A, a second drive circuit 121B, and an A / D converter 25.

[0061] The first drive / detection circuit 121A is electrically connected to the detection electrode 102 via wiring 110A. Furthermore, the first drive / detection circuit 121A includes an operational amplifier 30, a feedback resistor 40, a feedback capacitor 50, and a first AC voltage circuit 60 as a first AC power supply.

[0062] The first AC voltage circuit 60 generates a first AC drive voltage V1 and applies the first AC drive voltage V1 to the non-inverting input terminal (+) of the operational amplifier 30.

[0063] The inverting input terminal (-) of operational amplifier 30 is connected to the detection electrode 102 via wiring 110A, and the non-inverting input terminal (+) of operational amplifier 30 is connected to the first AC voltage circuit 60. Operational amplifier 30 amplifies the voltage difference between the inverting input terminal (-) connected to the detection electrode 102 and the non-inverting input terminal (+) to which the first AC drive voltage V1 is applied, and outputs an output voltage Vo. A feedback resistor 40 and a feedback capacitor 50 are connected in parallel between the output terminal and the inverting input terminal (-) of operational amplifier 30, and negative feedback is applied. The resistance value of feedback resistor 40 can be changed. The capacitance value of feedback capacitor 50 can be adjusted. Operational amplifier 30 outputs the change in capacitance in detection electrode 102, based on the change Ie of current Is flowing through detection electrode 102, as the output voltage Vo. The output voltage Vo is converted into a detection signal Ds via A / D converter 25.

[0064] The second drive circuit 121B includes a second AC voltage circuit 70 as a second AC power supply. The second AC voltage circuit 70 is electrically connected to the side shielding electrode 103 and the third back shielding electrode 112 via wiring 110A-2. The second drive circuit 121B generates a second AC drive voltage V2 that has the same frequency and phase as the first AC drive voltage V1 via the second AC voltage circuit 70.

[0065] However, in one embodiment of the capacitance sensor 100, the detection circuit 120 can make the amplitude of the second AC driving voltage V2 applied from the second driving circuit 121B to the side shielding electrode 103 and the third back shielding electrode 112 greater than the amplitude of the first AC driving voltage V1 applied from the first driving and detection circuit 121A to the detection electrode 102.

[0066] In this case, regarding one embodiment of the capacitive sensor 100, the parasitic capacitance between the detection electrode 102 and the ground potential and the side ground electrode 104 can be effectively reduced through the parasitic capacitance Crs(c) between the detection electrode 102 and the first back-side shielding electrode 106, and a detection signal with a high SN ratio can be obtained through the detection electrode 102. Furthermore, the output voltage Vo of the operational amplifier 30 can be prevented from saturating, and the dynamic range of the output voltage Vo can be increased.

[0067] (An example of detection processing of detection circuit 120 (first example)) Figure 7 is a flowchart showing an example (first example) of the detection processing of detection circuit 120 provided with a capacitance sensor 100 in an embodiment.

[0068] First, the detection circuit 120 will detect the capacitance of each monolithic electrode 102A (step S201).

[0069] Next, the detection circuit 120 will determine whether there is a single electrode 102A whose capacitance exceeds a specific threshold value based on the capacitance of each single electrode 102A detected in step S201 (step S202).

[0070] In step S202, if it is determined that there is no single electrode 102A with a capacitance exceeding a specific threshold value (step S202: NO), the detection circuit 120 will return the processing to step S201.

[0071] On the other hand, in step S202, if it is determined that there is a single electrode 102A with a capacitance exceeding a certain threshold (step S202: YES), the detection circuit 120 will count the number of single electrodes 102A with a capacitance exceeding the predetermined threshold (step S203 (counting process)).

[0072] Then, the detection circuit 120 calculates the number of detected objects 20 placed on the capacitance sensor 100 based on the number of single electrodes 102A whose capacitance exceeds a certain threshold value counted in step S202 (step S204 (number of objects placed)).

[0073] For example, when the number of single electrodes 102A with capacitance exceeding a certain threshold is A and the number of single electrodes 102A required to detect one object 20 is B, the detection circuit 120 calculates the number of objects 20 to be detected by formula (A÷B).

[0074] Then, the detection circuit 120 will output the number of detected objects 20 placed on the capacitance sensor 100 as calculated in step S204 (step S205).

[0075] Next, the detection circuit 120 will determine whether the number of detected objects 20 on the capacitance sensor 100 has increased or decreased by comparing the number of detected objects 20 on the capacitance sensor 100 calculated in step S204 with the number of detected objects 20 previously on the capacitance sensor 100 (step S206).

[0076] In step S206, if it is determined that the number of detected objects 20 placed on the capacitance sensor 100 has increased or decreased (step S206: YES), the detection circuit 120 will output the increase or decrease number of detected objects 20 placed on the capacitance sensor 100 (step S207 (increase / decrease output process)) and end the series of processes shown in FIG7.

[0077] On the other hand, in step S206, if it is determined that the number of detected objects 20 placed on the capacitance sensor 100 has not increased or decreased (step S206: NO), the detection circuit 120 will end the series of processes shown in FIG7.

[0078] (An example of detection processing of detection circuit 120 (second example)) Figure 8 is a flowchart showing an example (second example) of the detection processing of detection circuit 120 provided with a capacitance sensor 100 in an embodiment.

[0079] First, the detection circuit 120 will detect the capacitance of each monolithic electrode 102A (step S301).

[0080] Next, the detection circuit 120 will determine whether there is a single electrode 102A whose capacitance exceeds a specific threshold value based on the capacitance of each single electrode 102A detected in step S301 (step S302).

[0081] In step S302, if it is determined that there is no single electrode 102A with a capacitance exceeding a specific threshold value (step S302: NO), the detection circuit 120 will return the processing to step S301.

[0082] On the other hand, in step S302, if it is determined that there is a single electrode 102A with a capacitance exceeding a certain threshold (step S302: YES), then the continuous single electrode 102A portion with a capacitance exceeding the certain threshold is identified as a unit group, and it is determined whether there is a unit group containing a certain number or more of continuous single electrodes 102A (step S303).

[0083] In step S303, if it is determined that there is no unit group containing a specific number or more of continuous single electrodes 102A (step S303: NO), the detection circuit 120 will return the processing to step S301.

[0084] On the other hand, in step S303, if it is determined that there is a unit group containing a specific number or more of continuous single electrodes 102A (step S303: YES), the detection circuit 120 will calculate the number of detected objects 20 placed on the unit group based on the number of continuous single electrodes 102A contained in each unit group containing a specific number or more of continuous single electrodes 102A (step S304).

[0085] For example, the detection circuit 120 calculates the number of detected objects 20 placed on the unit group by formula (C÷B) when the number of continuous monolithic electrodes 102A contained in the unit group is C and the number of monolithic electrodes 102A required to detect one detected object 20 is B.

[0086] Then, the detection circuit 120 will output the number of detected objects 20 in each unit group calculated in step S304 (step S305).

[0087] Next, the detection circuit 120 calculates the total number of detected objects 20 placed on the capacitance sensor 100 based on the number of detected objects 20 in each unit group calculated in step S304, and determines whether the number of detected objects 20 placed on the capacitance sensor 100 has increased or decreased by comparing the total number of detected objects 20 placed on the capacitance sensor 100 with the total number of detected objects 20 previously placed on the capacitance sensor 100 (step S306).

[0088] In step S306, if it is determined that the number of detected objects 20 placed on the capacitance sensor 100 has increased or decreased (step S306: YES), the detection circuit 120 will output the increase or decrease number of detected objects 20 placed on the capacitance sensor 100 (step S307) and end the series of processes shown in FIG8.

[0089] On the other hand, in step S306, if it is determined that the number of detected objects 20 placed on the capacitance sensor 100 has not increased or decreased (step S306: NO), the detection circuit 120 will end the series of processes shown in FIG8.

[0090] The detection circuit 120 can accurately identify and output the number of detected objects 20 placed on the capacitive sensor 100 and their increase or decrease by performing a series of processes shown in FIG7 or FIG8.

[0091] In particular, the detection circuit 120 calculates the number of detected objects 20 placed on the capacitance sensor 100 by using the above formula (A÷B) or the above formula (C÷B). Therefore, even when multiple detected objects 20 are placed together, the number of detected objects 20 can be accurately calculated without mistakenly detecting them as a single large detected object 20.

[0092] However, in the series of processes shown in FIG7 or FIG8, it may further include, in the state where the detected object 20 is placed on the capacitance type sensor 100, the capacitance of the single electrode 102A with the smallest capacitance among the plurality of single electrodes 102A set at the position overlapping with the detected object 20 when viewed from above, is determined as the threshold value determination process for the above-mentioned specific threshold value used in the judgment process of step S202 or step S302.

[0093] Therefore, even if the overlap between the detection object 20 and the detection object 20 is small when viewed from above due to the shape of the detection object 20 or the offset of the placement position of the detection object 20, resulting in a small electrostatic capacitance of the single electrode 102A, the detection circuit 120 can still count the single electrode 102A as a single electrode 102A exceeding a specific threshold value.

[0094] (Experimental Example) The experimental example will be described below with reference to Figures 9 to 13.

[0095] <Experimental Conditions> Figure 9 shows the experimental conditions used in the experimental example. In this experimental example, as shown in Figure 9, the placement state of the object to be detected 20 on the conveyor 21 is changed, and the change in capacitance caused by the change in placement state is detected by a capacitance sensor 100 of one embodiment, which is disposed below the conveyor 21 at a distance of 3 mm. That is, in this experimental example, the object to be detected 20 is placed separately from the capacitance sensor 100 (so-called floating placement), so the capacitance sensor 100 is under relatively harsh conditions for detecting the object to be detected 20. However, the conveyor 21 is composed of a plurality of rotatable rollers (diameter: 6 mm) arranged side by side along the vertical direction of the paper at a distance of 2.2 mm.

[0096] <Products> Figure 10 is a table showing the products used in the experimental example. In this experimental example, as shown in Figure 10, products A, B, and C are used as examples of the detection target 20.

[0097] • Product A: PET bottle beverage (water, vertically placed) ･･･Water: High conductivity • Product B: Boxed snacks (chocolate, vertically placed) ･･･Container: Conductive aluminum vapor-deposited bag • Product C: Boxed snacks (chocolate, vertically placed) ･･･Container: Non-conductive material

[0098] <First Experimental Results> Figure 11 is a table showing the first experimental results of the experimental example. Figure 11 shows the experimental results when using product A shown in Figure 10.

[0099] As shown in Figure 11, in the first experimental results, for the verification of the "increase or decrease" of the product type, when the number of product A placed on the conveyor 21 changed to 5, 4, 3, 2 and 1 respectively, sufficient change in the single electrode detection signal intensity and sufficient SN ratio (above 20dB) could be obtained.

[0100] In addition, as shown in Figure 11, in the first experimental results, for the verification of the "increase or decrease" of the product type, when the number of product A placed on the conveyor 21 changes to 5, 4, 3, 2 and 1 respectively, the detection circuit 120 provided by the capacitance sensor 100 can perform the detection process shown in Figure 7. Based on the number of single electrodes 102A whose capacitance reaches a certain threshold value or above, the number of product A placed on the conveyor 21 can be accurately determined.

[0101] Also, as shown in Figure 11, in the first experimental results, for the verification type "configuration", when 5 products A are placed on the conveyor 21 in 5 different configuration modes, sufficient change in detection signal strength and sufficient SN ratio (above 20dB) can be obtained.

[0102] Furthermore, as shown in Figure 11, in the first experimental results, for the verification type "configuration", when 5 products A are placed on the conveyor 21 in 5 different configuration modes, the detection circuit 120 provided by the capacitance sensor 100 can perform the detection process shown in Figure 7. Based on the number of single electrodes 102A whose capacitance reaches a certain threshold value or above, the number of products A placed on the conveyor 21 can be accurately determined.

[0103] <Results of Experiment 2> Figure 12 is a table showing the results of the second experiment in the experimental example. Figure 12 shows the experimental results when using product B shown in Figure 10.

[0104] As shown in Figure 12, in the second experimental results, for the verification of the "increase or decrease" of the product type, when the number of products B placed on the conveyor 21 changed to 4, 3, 2 and 1 respectively, sufficient change in the single electrode detection signal intensity and sufficient SN ratio (above 20dB) were obtained.

[0105] Furthermore, as shown in Figure 12, in the second experimental results, for the verification of the "increase or decrease" of the product type, when the number of products B placed on the conveyor 21 changes to 4, 3, 2, and 1 respectively, the detection process shown in Figure 7 can be performed by the detection circuit 120 provided by the capacitance sensor 100. The number of single electrodes 102A with capacitance reaching a certain threshold value or above can be accurately determined to determine the number of products B placed on the conveyor 21.

[0106] <Results of Experiment 3> Figure 13 is a table showing the results of the third experiment of the experimental example. Figure 13 shows the experimental results when using product C shown in Figure 10.

[0107] As shown in Figure 13, in the third experimental results, for the verification of the "increase or decrease" of the product type, when the number of products C placed on the conveyor 21 changed to 5, 4, 3, 2 and 1 respectively, sufficient change in the single electrode detection signal intensity and sufficient SN ratio could be obtained.

[0108] Furthermore, as shown in Figure 13, in the third experimental results, for the verification of the "increase or decrease" of the product type, when the number of products C placed on the conveyor 21 changes to 5, 4, 3, 2, and 1 respectively, the detection process shown in Figure 7 can be performed by the detection circuit 120 provided by the capacitance sensor 100. The number of single electrodes 102A with capacitance reaching a certain threshold value or above can be accurately determined to determine the number of products C placed on the conveyor 21.

[0109] In summary, in this experimental example, even when the detector object 20 (product A) containing not only high capacitance, but also detector object 20 (product B) with conductive aluminum vapor-deposited inner packaging and relatively low overall capacitance, and detector object 20 (product C) with containers without conductive material and low overall capacitance are floated on the conveyor 21, it has been confirmed that the capacitance sensor 100 of one embodiment can accurately specify the number of detector objects 20 placed on the conveyor 21.

[0110] In this embodiment, the capacitance-type sensor 100 has a plurality of single electrodes 102A on the detection electrode 102, and a side grounding electrode 104 is provided with a side shielding electrode 103, thereby reducing the parasitic capacitance between the detection electrode 102 and the side grounding electrode 104, improving the SN ratio, and even if the capacitance of the detected object 20 detected by the detection electrode 102 is small, it can be detected with high sensitivity. Furthermore, by providing each shielding electrode 103, 106, 109, 112, the parasitic capacitance is reduced and the intrusion of external noise is prevented.

[0111] An embodiment of the present invention has been described in detail above, but the present invention is not limited to these embodiments. Various modifications or alterations can be made within the scope of the spirit of the present invention as described in the patent claims.

[0112] For example, in the capacitive sensor 100 of this embodiment, two detection electrodes 102 (left and right) and a pair of side shielding electrodes 103 (left and right) are provided on the surface 101A of the first insulating layer 101. However, it is not limited to this. For example, as in the modified example described later, one detection electrode 102 may be provided on the surface 101A of the first insulating layer 101. In this case, a rectangular frame-shaped side shielding electrode 103 (i.e., a side shielding electrode 103 having two straight portions 103A) surrounding one detection electrode 102 may be provided on the surface 101A of the first insulating layer 101, or two straight side shielding electrodes 103 that clamp one detection electrode 102 may be provided.

[0113] Furthermore, in the capacitance type sensor 100 of this embodiment, all shielding electrodes 109, 112 and back ground electrode 113 are provided, but it is not limited to this, and any one of the shielding electrodes 109, 112 and back ground electrode 113 may not be provided.

[0114] (Modified Example) Figure 14 is a plan view of a modified embodiment of the capacitive sensor 100-2. Figure 15 is a cross-sectional view of a modified embodiment of the capacitive sensor 100-2 along section AA (refer to Figure 14). Figure 16 is an exploded plan view of a modified embodiment of the capacitive sensor 100-2. Figure 17 is a circuit model diagram of a modified embodiment of the capacitive sensor 100-2 (when the object 20 is detected to be present on the capacitive sensor 100-2).

[0115] As shown in Figures 14 to 17, the capacitance sensor 100-2 of a modified example differs from the capacitance sensor 100 in that a detection electrode 102, two linear side shielding electrodes 103 that hold the detection electrode 102, and a side grounding electrode 104 arranged in parallel with the detection electrode 102 are provided on the surface 101A of the first insulating layer 101.

[0116] As shown in FIG14, the detection electrode 102 of the capacitance sensor 100-2 of a modified example is the same as the detection electrode 102 of the capacitance sensor 100, which is located at a point where a plurality of single electrodes 102A are arranged side by side in the front-back direction (Y-axis direction).

[0117] Furthermore, in a modified example of the capacitive sensor 100-2, each of the plurality of monolithic electrodes 102A is electrically connected to a corresponding wire 110A in the wiring group 110 disposed in the wiring layer L3 (within the notch 109A) through a corresponding first through hole 111 (see Figure 15).

[0118] Therefore, the capacitance type sensor 100-2 of a modified example is the same as the capacitance type sensor 100. It can apply a first AC driving voltage V1 to each of the plurality of monolithic electrodes 102A through the detection circuit 120 (which is set separately from the capacitance type sensor 100-2 in this modified example) via the wiring group 110, thereby detecting the capacitance change of each monolithic electrode 102A.

[0119] Then, regarding a modified example of the capacitance type sensor 100-2, similar to the capacitance type sensor 100, it is possible to precisely specify the area on the capacitance type sensor 100 on which the detection object 20 is placed based on the capacitance change of each of the plurality of monolithic electrodes 102A, and through the detection circuit 120, perform the processing shown in FIG7 or FIG8, etc., the number of detection objects 20 placed on the capacitance type sensor 100 can be easily and accurately calculated.

[0120] However, since the capacitance type sensor 100-2 of a modified example is provided with only one detection electrode 102, as shown in Figures 14 to 17, no connecting member 102B for connecting the left and right monolithic electrodes 102A to each other is provided in the bridging wiring layer L2.

[0121] Furthermore, regarding a modified example of the capacitance sensor 100-2, two linear side shielding electrodes 103 are provided on the surface 101A of the first insulating layer 101 to hold a detection electrode 102. However, since the two linear side shielding electrodes 103 are simultaneously driven by the first AC driving voltage V1 applied from the detection circuit 120, their function is the same as that of the rectangular frame-shaped side shielding electrode 103 (a pair of linear portions 103A on the left and right sides) of the capacitance sensor 100.

[0122] Furthermore, regarding a modified example of the capacitance sensor 100-2, it is the same as the capacitance sensor 100, having a side grounding electrode 104, a side shielding electrode 103, a first back shielding electrode 106, a second back shielding electrode 109, a third back shielding electrode 112, and a back grounding electrode 113. Therefore, it can exert the same effects brought by these electrodes as the capacitance sensor 100 (capacitance amplification effect of detecting object 20, parasitic capacitance reduction effect, and prevention of external noise superposition effect, etc.). [Simplified Explanation of the Diagram]

[0007] [Figure 1] Plan view of a capacitance sensor according to an embodiment [Figure 2] Cross-sectional view of a capacitance sensor according to an embodiment along section AA [Figure 3] Cross-sectional view of a capacitance sensor according to an embodiment along section BB [Figure 4] Exploded plan view of a capacitance sensor according to an embodiment [Figure 5] Circuit model diagram of a capacitance sensor according to an embodiment (when an object is detected to be present on the capacitance sensor) [Figure 6] Example circuit configuration diagram of the capacitance detection unit of a capacitance sensor according to an embodiment [Figure 7] Flowchart showing one example (first example) of the detection process of the detection circuit of a capacitance sensor according to an embodiment [Figure 8] Flowchart showing a capacitance sensor according to an embodiment A flowchart of one example (Example 2) of the detection processing of the detection circuit of the capacitance sensor [Fig. 9] A diagram showing the experimental conditions used in the experimental example [Fig. 10] A table showing the products used in the experimental example [Fig. 11] A table showing the first experimental result of the experimental example [Fig. 12] A table showing the second experimental result of the experimental example [Fig. 13] A table showing the third experimental result of the experimental example [Fig. 14] A plan view of a modified embodiment of the capacitance sensor [Fig. 15] A cross-sectional view of a modified embodiment of the capacitance sensor along section AA [Fig. 16] An exploded plan view of a modified embodiment of the capacitance sensor [Fig. 17] A circuit model diagram of a modified embodiment of the capacitance sensor (when the object is detected to be present on the capacitance sensor).

Claims

1. A capacitance-type sensor, characterized by comprising: a first insulating layer; a detection electrode extending along a first direction on the surface of the first insulating layer; a side shielding electrode disposed side-by-side with the detection electrode on the surface of the first insulating layer; a side grounding electrode disposed side-by-side with the detection electrode and the side shielding electrode on the surface of the first insulating layer and connected to a ground potential; and a first back shielding electrode disposed on another side of the first insulating layer and facing the detection electrode through the first insulating layer; the detection electrode is subjected to a first AC driving voltage; the side shielding electrode and the first back shielding electrode are subjected to a second AC driving voltage having the same frequency and phase as the first AC driving voltage; the detection electrode has a plurality of monolithic electrodes disposed side-by-side at intervals in the first direction; and the side shielding electrode is disposed side-by-side between the detection electrode and the side grounding electrode.

2. The capacitive sensor as described in claim 1, wherein, It comprises: a second insulating layer disposed on the back side of the aforementioned first back shielding electrode; a wiring layer disposed on the back side of the aforementioned second insulating layer; and a third insulating layer disposed on the back side of the aforementioned wiring layer; the aforementioned wiring layer comprises: a second back shielding electrode disposed covering the back side of the aforementioned second insulating layer; and a wiring group disposed in the notch formed by the aforementioned second back shielding electrode, wherein one end is connected to a detection circuit, and the other end is connected to each of the aforementioned plurality of monolithic electrodes through a through hole penetrating the aforementioned first insulating layer, the aforementioned first back shielding electrode, and the second insulating layer.

3. The capacitive sensor as described in claim 2, wherein, The aforementioned second back-side shielding electrode system applies the aforementioned second AC drive voltage.

4. The capacitive sensor as described in claim 3, wherein, It has a third back-side shielding electrode disposed on the back side of the aforementioned third insulating layer; the aforementioned third back-side shielding electrode is subject to the aforementioned second AC driving voltage.

5. The capacitive sensor as described in claim 4, wherein, It further includes a back grounding electrode that is separated from and opposite to the aforementioned third back shielding electrode on the back side of the aforementioned third back shielding electrode and connected to the grounding potential.

6. The capacitive sensor as described in claim 1, wherein, The aforementioned side shielding electrode system has two parallel straight sections, and the aforementioned detection electrode system is disposed between the aforementioned two straight sections.

7. A detection circuit, such as the detection circuit for a capacitance-type sensor described in claim 1, characterized in that it comprises: a first drive / detection circuit for applying the first AC drive voltage to the aforementioned detection electrode and detecting changes in current flowing through the aforementioned detection electrode; and a second drive circuit for applying a second AC drive voltage to the aforementioned first back-side shielding electrode and the aforementioned side-side shielding electrode; wherein the amplitude of the aforementioned second AC drive voltage is greater than the amplitude of the aforementioned first AC drive voltage.

8. A detection circuit, such as the detection circuit for a capacitive sensor according to claim 3, characterized in that it comprises: a first drive / detection circuit for applying the first AC drive voltage to the aforementioned detection electrode and detecting changes in current flowing through the aforementioned detection electrode; and a second drive circuit for applying the aforementioned second AC drive voltage to the aforementioned first back-side shielding electrode, the aforementioned side-side shielding electrode, and the second back-side shielding electrode; wherein, The amplitude of the aforementioned second AC drive voltage is greater than the amplitude of the aforementioned first AC drive voltage.

9. A capacitance-type sensor, characterized by comprising: a first insulating layer; a side grounding electrode disposed on the surface of the first insulating layer and connected to a ground potential; a pair of detection electrodes disposed side-by-side on both sides of the side grounding electrode on the surface of the first insulating layer; a pair of side shielding electrodes disposed side-by-side on each of the pair of detection electrodes on the surface of the first insulating layer; and a first back shielding electrode disposed on the other side of the first insulating layer and facing the detection electrodes through the first insulating layer; the pair of detection electrodes being subjected to a first AC driving voltage; the pair of side shielding electrodes and the first back shielding electrode being subjected to a second AC driving voltage having the same frequency and phase as the first AC driving voltage; each of the pair of detection electrodes having: a plurality of monolithic electrodes spaced apart and disposed side-by-side along a first direction; and the pair of side shielding electrodes being disposed side-by-side between each of the pair of detection electrodes and the side grounding electrode.

10. The capacitive sensor as described in claim 9, wherein, It has a plurality of single electrode pairs consisting of one of the aforementioned detection electrodes and the other of the aforementioned detection electrodes; the plurality of the aforementioned single electrode pairs are arranged side by side with a distance between them along the aforementioned first direction; and each of the aforementioned plurality of single electrode pairs is such that the aforementioned single electrode of one of the aforementioned detection electrodes and the aforementioned single electrode of the other of the aforementioned detection electrodes are connected by a bridging wiring layer through the aforementioned first insulating layer.

11. The capacitive sensor as described in claim 10, wherein, Each of the aforementioned monolithic electrode pairs is such that one of the aforementioned detection electrodes and the other of the aforementioned detection electrodes are connected through a through-hole penetrating the aforementioned first insulating layer by a connecting member disposed on the aforementioned bridging wiring layer; and in the aforementioned bridging wiring layer, the aforementioned first back-side shielding electrode is disposed on both outer sides of the aforementioned connecting member.

12. The capacitive sensor as described in claim 11, wherein, It comprises: a second insulating layer disposed on the back side of the aforementioned first back shielding electrode; and a second back shielding electrode disposed covering the back side of the aforementioned second insulating layer.

13. The capacitive sensor as described in claim 9, wherein, It comprises: a second insulating layer disposed on the back side of the aforementioned first back shielding electrode; and a wiring layer disposed on the back side of the aforementioned second insulating layer; the aforementioned wiring layer having a wiring group having one end connected to a detection circuit and the other end connected to each of the aforementioned plurality of monolithic electrodes through a through hole penetrating the aforementioned first insulating layer, the aforementioned first back shielding electrode and the second insulating layer.

14. The capacitive sensor as described in claim 13, wherein, The aforementioned wiring layer has a second back shielding electrode that covers the back side of the aforementioned second insulating layer, and the aforementioned wiring group is disposed within the notch formed by the aforementioned second back shielding electrode.

15. The capacitive sensor as described in claim 14, wherein, It includes: a third insulating layer disposed on the back side of the aforementioned wiring layer; and a third back shielding electrode disposed on the back side of the aforementioned third insulating layer; the aforementioned third back shielding electrode is subjected to the aforementioned second AC driving voltage.

16. The capacitive sensor as described in claim 15, wherein, It further includes a back grounding electrode that is separated from and opposite to the aforementioned third back shielding electrode on the back side of the aforementioned third back shielding electrode and connected to the grounding potential.

17. The capacitive sensor as described in claim 9, wherein, Each of the aforementioned pair of side-shielding electrodes has two parallel straight sections, and each of the aforementioned pair of detection electrodes is disposed between the aforementioned two straight sections.

18. A detection circuit, such as the detection circuit for a capacitance-type sensor described in claim 9, characterized in that it comprises: a first drive / detection circuit for applying the first AC drive voltage to the aforementioned detection electrode and detecting changes in current flowing through the aforementioned detection electrode; and a second drive circuit for applying the aforementioned second AC drive voltage to a side shielding electrode and the aforementioned first back shielding electrode; wherein the amplitude of the aforementioned second AC drive voltage is greater than the amplitude of the aforementioned first AC drive voltage.

19. A detection circuit, such as the detection circuit for a capacitance-type sensor as described in claim 15, characterized in that it comprises: a first drive / detection circuit for applying the first AC drive voltage to the aforementioned detection electrode and detecting changes in current flowing through the aforementioned detection electrode; and a second drive circuit for applying the aforementioned second AC drive voltage to a side shielding electrode, the aforementioned first back shielding electrode, the aforementioned second back shielding electrode, and the aforementioned third back shielding electrode; wherein the amplitude of the aforementioned second AC drive voltage is greater than the amplitude of the aforementioned first AC drive voltage.

20. The capacitive sensor as described in claim 17, wherein, It comprises: a second insulating layer disposed on the back side of the aforementioned first back shielding electrode; and a wiring layer disposed on the back side of the aforementioned second insulating layer; the aforementioned wiring layer having a wiring group having one end connected to a detection circuit and the other end connected to each of the aforementioned plurality of monolithic electrodes through a through hole penetrating the aforementioned first insulating layer, the aforementioned first back shielding electrode and the second insulating layer.

21. The capacitive sensor as described in claim 20, wherein, The aforementioned wiring layer has a second back shielding electrode that is provided to cover the back side of the aforementioned second insulation layer and is subject to the aforementioned second AC drive voltage, and the aforementioned wiring group is disposed within the notch formed by the aforementioned second back shielding electrode.

22. The capacitive sensor as described in claim 21, wherein, It includes: a third insulating layer disposed on the back side of the aforementioned wiring layer; and a third back shielding electrode disposed on the back side of the aforementioned third insulating layer; the aforementioned third back shielding electrode is subjected to the aforementioned second AC driving voltage.

23. The capacitive sensor as described in claim 22, wherein, It further includes a back grounding electrode that is separated from and opposite to the aforementioned third back shielding electrode on the back side of the aforementioned third back shielding electrode and connected to the grounding potential.

24. A detection method, performed by a detection circuit of a capacitance sensor as described in claim 1, characterized by comprising: a counting step of counting the number of monolithic electrodes whose capacitance exceeds a specific threshold; a quantity calculation step of calculating the number of detected objects mounted on the capacitance sensor by dividing the number of monolithic electrodes counted in the counting step by the number of monolithic electrodes corresponding to one detected object; and an increment / decrement output step of outputting an increment / decrement of the number of detected objects mounted on the capacitance sensor by comparing the number of detected objects previously calculated in the quantity calculation step with the latest number of detected objects calculated in the quantity calculation step.

25. The testing method as described in claim 24, wherein, The method further includes a threshold value determination step in which, when the detected object is placed on the aforementioned capacitance sensor, the capacitance of the single electrode with the smallest capacitance among the plurality of single electrodes disposed at the position overlapping with the detected object when viewed from above is determined as the aforementioned specific threshold value.

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