JP2005156291A - Capacity detection type sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacity detection type sensor capable of acquiring a detection signal having reduced manufacturing cost, a high resolution and a high S/N ratio when detecting a shape having a fine and predetermined area such as a fingerprint. <P>SOLUTION: This capacity detection type sensor is a capacity detection type sensor formed by disposing matrically row wiring and column wiring on a substrate. The sensor has a driving electrode elongated from the row wiring on a crossing part between the row wiring and the column wiring, a detection electrode pairing with the driving electrode and elongated from the column wiring adjacently to the driving electrode, and a floating electrode disposed on the upper part of the driving electrode and the detection electrode through an interlayer insulating film. The sensor is constituted so as to detect a displacement current changing corresponding to the distance between a detection object and the floating electrode and flowing from the driving electrode to the detection electrode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sensor for measuring fine unevenness of an object to be measured, and a capacitance detection type sensor suitable for use in a touch pad or the like.

As a sensor for detecting fine irregularities on the surface of the object to be measured pressed against the detection surface, for example, Patent Document 1 is known as a sensor for measuring a change in electrostatic capacitance between electrodes arranged in an array and the object to be detected. It has been.
In addition, as a touch pad that measures the contact position of a finger or the like from the change in capacitance, the row wiring and the column wiring are crossed through an insulator, and the capacitance at the intersection changes depending on the object to be detected. For example, Patent Document 2 is known.
JP 2000-213908 A Japanese Translation of National Publication No. 09-51086

  However, the technique described in Patent Document 1 requires a transistor for selecting a detection electrode. For example, when detecting a minute shape such as a fingerprint, it is necessary to dispose detection electrodes and switching transistors at a pitch of 100 μm or less and continuously over the entire detection range, and these are integrated on a semiconductor substrate. It is essential to do. Therefore, when a detector having a large area is configured, there is a problem that the cost increases due to an increase in the number of processes and a decrease in yield.

In the technique of Patent Document 2, in order to secure detection sensitivity to some extent, it is necessary to secure detection capacitance to some extent and to increase the capacitance at the wiring intersection.
When this capacity is increased, it is necessary to increase the wiring width of the row wiring and the column wiring that form the intersection, and the wiring pitch of each of the row wiring and the column wiring cannot be reduced. As a result, there is a problem that when a certain degree of sensitivity is obtained, the fine structure cannot be detected (detection with high resolution for the detection target).
Furthermore, in the technique of Patent Document 2, as described above, since the capacitance of the intersection cannot be increased, the capacitance change amount cannot be obtained at a sufficient level, and the detection signal level is insufficient. There was a drawback of not having it.

  The present invention has been made in view of the above circumstances, and when detecting a fine shape such as a fingerprint having a predetermined area, detection with a reduction in manufacturing cost, high resolution, and a large S / N ratio is achieved. An object of the present invention is to provide a capacitance detection type sensor capable of obtaining a signal.

  The capacitance detection type sensor of the present invention is a capacitance detection type sensor in which row wiring and column wiring are arranged in a matrix on a substrate, and extends from the column wiring at the intersection of the row wiring and column wiring. A drive electrode paired with the drive electrode, a detection electrode extending from the row wiring adjacent to the drive electrode, and a floating disposed above the drive electrode and the detection electrode via an interlayer insulating film A displacement current flowing from the drive electrode to the detection electrode, which varies depending on the distance between the object to be detected and the floating electrode.

The capacitance detection type sensor of the present invention does not need to use an expensive material used when a transistor is formed using a semiconductor substrate or the like, and can be manufactured with a simple manufacturing process. Including the reduction of manufacturing costs.
Further, the capacitance detection type sensor of the present invention has a flat floating electrode, drive electrode, and detection electrode even when the pitch of each of the column wiring and the row wiring is reduced and the dot pitch is reduced in order to increase the detection resolution. Since it is configured to overlap by visual observation and is capacitively coupled, by measuring the change in displacement current flowing through the floating electrode from the drive electrode to the detection electrode due to the detected object approaching the floating electrode Thus, the capacitance change of each dot (intersection) can be detected largely, and the S / N ratio of the signal level of the detection signal can be improved.
Furthermore, in the capacitance detection type sensor of the present invention, when the detected object is not in the vicinity of the floating electrode, the leakage electric field to the upper part of the floating electrode is extremely small. Therefore, unlike the optical sensor, the dielectric substance attached to the upper part of the sensor When applied to a fingerprint sensor or the like, it is difficult to be affected by residual fingerprints.

  In the capacitance detection type sensor of the present invention, each of the drive electrode and the detection electrode is covered with the floating electrode except for a connection portion with a column wiring or a row wiring. And the displacement current can be greatly changed depending on the distance between the detection object and the floating electrode.

  Since the capacitance detection type sensor of the present invention is provided with an insulating film on the floating electrode, the floating electrode can be protected.

  In the capacitance detection type sensor according to the present invention, an opening that exposes a part of the floating electrode is provided in a predetermined portion of the insulating film, so that it can be driven depending on whether or not the object to be detected is in contact with the floating electrode. Since the displacement current flowing from the electrode to the detection electrode changes significantly, even when the dot pitch is reduced, the displacement that flows from the drive electrode to the detection electrode via the floating electrode due to the detected object approaching the floating electrode By measuring the change in current, the capacitance change of each dot (intersection) can be detected greatly, and the S / N ratio of the signal level of the detection signal can be improved.

  In the capacitance detection type sensor according to the present invention, since the protruding portion that penetrates the insulating film and is electrically connected to the floating electrode is provided on the floating electrode, the detected object does not directly contact the floating electrode. Therefore, it is possible to make electrical contact with an object to be detected while protecting the floating electrode.

  As described above, since the sensor can be formed by a simpler method compared to the manufacturing of the integrated circuit, the manufacturing cost is reduced, and the driving voltage and the detection voltage are combined with the floating electrode. The displacement current between the detection voltage and the detection voltage changes greatly corresponding to the change of the floating electrode caused by the detection object, and the S / N ratio of the signal level of the detection signal can be improved. Is obtained.

In the capacitance detection type sensor of the present invention, row wiring and column wiring are arranged in a matrix on a substrate, and a drive extended from this column wiring at the intersection of the row wiring and column wiring. A pair of electrodes, a detection electrode extending from the row wiring adjacent to the drive electrode, and a floating electrode disposed on the drive electrode and the detection electrode via an interlayer insulating film. A displacement current flowing from the drive electrode to the detection electrode, which varies depending on the distance between the object to be detected and the floating electrode, is detected.
Here, the drive electrode and the detection electrode are formed so as to overlap the floating electrode, that is, capacitively coupled, and a displacement current flows from the drive electrode to the detection electrode via the floating electrode. ing.

A capacitance detection type sensor according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a capacitance detection type sensor according to the embodiment, FIG. 2 is an enlarged plan view of a main part of the capacitance detection type sensor of the present invention, and FIG. 3 is a line segment A in FIG. It is a line sectional view in -A.
The capacitance detection type sensor according to this embodiment is applied as a fingerprint sensor, and a plurality of row wirings 13 are arranged on the glass substrate 1 as a parallel in the first direction X formed by the first conductive film. And the detection electrode 3 extended from this row wiring 13 and the drive electrode 2 of this detection electrode 3 pair are formed.
On the row wiring 13, the detection electrode 3, and the drive electrode 2, a large number of arrays are arranged in parallel with the floating electrode 5 in the second direction Y intersecting the first direction X by the second conductive film via the interlayer insulating film 4. The column wiring 12 is formed.

Here, in the configuration of the detection electrode 3 and the drive electrode 2 and the floating electrode 5, the drive electrode 2 and the detection electrode 3 are overlapped so that the floating electrode 5 is completely covered in plan view. .
Each drive electrode 2 is electrically connected to the column wiring 12 through a contact 14 at one end. That is, the drive electrode 2 has a shape extending from the column wiring 12.
The passivation film 6 is provided on the floating electrode 5 and the column wiring 12 in order to protect from the external environment (such as moisture) when the second conductive film uses a metal or the like that is vulnerable to moisture. The part of the floating electrode 5 is a detection part (hereinafter referred to as a pixel) of the detection object.

For example, when assuming the detection of fingerprints, the row wiring 13 requires a position resolution of 500 dpi or more and a detection area of about 10 mm square, and thus is composed of a 0.1 μm thick ITO film as the first conductive film, 200 pieces are formed on a glass substrate 1 having a thickness of 0.7 mm at a pitch of 30 to 100 μm, for example, a pitch of 50 μm. The interlayer insulating film 4 may be any film in which SixNy (silicon nitride film) such as Si3N4 is laminated. Each row wiring 13 is connected to a capacitance detection circuit 11 that detects electrostatic capacitance.
The column wirings 12 are made of, for example, a 0.1 μm-thick lTO film as a second conductive film, and 200 lines are formed on the interlayer insulating film 4 at a pitch of 30 to 100 μm, for example, 50 μm. Each column wiring 12 is connected to the column selection circuit 10.
Such a column selection circuit 10 connects all except the column wiring 12 selected at the time of capacitance measurement to the ground side.

Next, an operation example of the capacitance detection type sensor according to the first embodiment will be described with reference to FIGS.
With the above structure, capacitance is generated between each drive electrode 2 and detection electrode 3 and the floating electrode 5 in each pixel, and the entire equivalent circuit is expressed as shown in FIG. In order to measure each capacitance from such a circuit, a circuit as shown in FIG. 4 is generally used. That is, an I / V conversion circuit 20 is provided in each of the row wirings 13 in the capacitance detection circuit 11, a displacement current is passed through the capacitance 100, and the I / V conversion circuit 20 configured by the operational amplifier 22 and the capacitance 21 is used. The current value of the displacement current is converted into a voltage value and output as an output Vo. The output Vo at this time is expressed by the following equation (1).

Here, after the measurement, the switch 23 is turned on to discharge the charge accumulated in the capacitor 21, and the switch 23 is turned off at the time of measurement.
However, in the present embodiment, the capacitance to be measured varies depending on the coupling capacitance between the finger (detected object) and the floating electrode 5.
Therefore, the capacitor 100 in FIG. 4 is replaced with an equivalent circuit of the capacitor 200 shown in FIG.
At this time, the output is expressed by the following equation (2).

  However, the capacitance value Ca is the capacitance value of the capacitance 101 between the drive electrode 2 and the floating electrode 5, and the capacitance value of the capacitance 102 between the detection electrode 3 and the floating electrode 5. Here, the capacitors 101 and 102 are formed to have the same capacitance value. The capacitance value Cb is a capacitance value of the parasitic capacitance 103 between the drive electrode 2 and the detection electrode 3. The capacitance value Cx is a capacitance value of the capacitance 100 between the floating electrode 5 and the object 7 to be detected.

FIG. 6 is a diagram showing the relationship between the distance between the sensor surface and the object 7 to be detected and the output of the sensor.
In an ideal case, when the detected object 7 is sufficiently far away, the capacitance value Cx = 0, and the output Vo is expressed by the following equation (3).

    When the detected object is sufficiently close or in contact, Cx = C0, and the output Vo is expressed by the following equation (4).

Here, a parallel plate capacitance having a size in plan view of the floating electrode 5 is formed by the detected object 7, the floating electrode 5, and the passivation film 6 interposed therebetween, and the capacitance value C0 is This is a numerical value obtained from the thickness of the passivation film 6, the area of the floating electrode 5, and the dielectric constant of the dielectric material.
That is, the output voltage Vo due to the displacement current flowing through the I / V converter 20 is the displacement current output from the capacitor 102 (capacitance value Ca) when the detected object 7 approaches the passivation film 6 and Cx approaches C0. Is reduced by being shunted by the capacitor 101 (capacitance value Ca) and the capacitor 100 (capacitance value Cx).

For example, SixNy (silicon nitride film; dielectric constant ε = 7) is used as the material of the interlayer insulating film 4 and the passivation film 6, the film thickness is 300 nm, and the floating electrode 5 is driven by 50 μm × 50 μm in the shape shown in FIG. When the layout in which the electrode 2 and the detection electrode 3 are 50 μm × 25 μm is used, the capacitance values are Ca = 170 fF, Cb = 10 fF, and CO = 340 fF.
When the capacitance values Cf = 1 pF and V1 = 5 V, Vo (off) = 0.48 V when the detected object 7 is sufficiently separated from the passivation film 6 and the detected object 7 is in contact with the passivation film 6. In this case, Vo (on) = 0.26V, and the output change of the difference voltage ΔVo = 0.22V can be obtained in the presence or absence of the object to be detected.
Further, since the output V0 changes monotonously as shown in FIG. 6 from the state in which the detected object 7 is sufficiently separated from the sensor surface (passivation film 6), the detection result is obtained at a multi-tone level corresponding to the distance. If the object to be detected is a fingerprint, the fingerprint shape can be captured faithfully.

Furthermore, as shown in FIG. 7, when each of the drive electrode 2 and the detection electrode 3 is covered with the floating electrodes 5A and 5B except for the column wiring 12 or the row wiring 13 and the connection portion with each wiring, Since the floating electrode 5B is also provided between the electrode 2 and the detection electrode 3, the electric field between the drive electrode 2 and the detection electrode 3 is shielded, the capacitance value Cb = 0 and the capacitance value Ca is approximately doubled. be able to.
At this time, in the capacitance detection type sensor according to the present embodiment, the floating electrode 5A formed of the second conductive film is formed on the glass substrate 1 and the first conductive film is interposed between the first insulating film 4A and the interlayer insulating film 4A. A large number of row wirings 13 arranged in parallel in the direction X, detection electrodes 3 extending from the row wirings 13, and drive electrodes 2 of pairs of the detection electrodes 3 are formed.
On the row wiring 13, the detection electrode 3, and the drive electrode 2, a large number of floating electrodes 5 </ b> B are arranged in parallel with the second direction Y intersecting the first direction X by the second conductive film through the interlayer insulating film 4 </ b> B. The column wiring 12 is formed.

Here, the floating electrode 5A and the floating electrode 5B are electrically connected by a contact, and as described above, the detection electrode 3 and the drive electrode are excluded except for the connection portion between the column wiring 12 and the row wiring 13. 2 is completely covered.
Each drive electrode 2 is electrically connected to the column wiring 12 through a contact 14 at one end.
The passivation film 6 is provided on the floating electrode 5 and the column wiring 12 in order to protect from the external environment (such as moisture) when the second conductive film uses a metal or the like that is vulnerable to moisture. The portion of the floating electrode 5B is a detection portion (hereinafter referred to as a pixel) of the detection object.

Thus, when the detected object 7 is separated from the passivation film 6 (the surface of the capacitance detection type sensor) with a sufficient distance, the output Vo (off) = 0.43V, and the detected object 7 is the passivation film. Vo (on) = 0.14V when touching 6 and the difference in voltage ΔVo = 0.29V can be increased.
Further, in order to obtain a larger voltage difference depending on the presence or absence of an object to be detected on the surface of the capacitance detection type sensor, the thickness of the passivation film 6 is reduced, or the material of the passivation film 6 is made of TiO2 (titanium oxide) or the like. It is also effective to use a high dielectric constant material.

That is, when the detected object 7 (conductor such as a finger) is brought into contact with the surface of the capacitance detection type sensor according to the first embodiment, the floating electrode 5 and the detected object 7 are in the pixel corresponding to the concave portion of the fingerprint. It has a predetermined distance and becomes a voltage value of output Vo (off), and there is not much change from the initial voltage value when it is separated with a sufficient distance.
On the other hand, in the pixel corresponding to the convex portion of the fingerprint, the floating electrode 5 and the detected object 7 come into contact with each other to obtain a voltage value of output Vo (in), and a sufficient ΔVo is obtained between the above V (off). be able to.

  The capacitance sensor of the present embodiment has a configuration as described above, and detection corresponding to an intersection where the row wiring 13 and the column wiring 12 intersect as shown in the equivalent circuits shown in FIGS. 4 and 5. A change in capacitance in the portion can be obtained as a change in displacement current and detected by the I / V conversion circuit 20. In this way, by detecting changes in the capacitance of a large number of detection portions that occur when a fine uneven surface is pressed against the surface of the passivation film 6, the shape of the uneven surface of the detected object 7 is used as signal data. It becomes possible to output.

The capacitance detection circuit 11 uses the I / V conversion circuit 20 as shown in FIGS. 5 and 6 as described above, and all the column wirings other than the column wiring 12 selected by the column selection circuit 10 are grounded during measurement. All of the capacitances that are not to be measured on the same row wiring 13 are input in parallel to the measurement system as parasitic capacitances, but the electrodes on the opposite side of the parasitic capacitances are connected to the ground side. It is possible to cancel by being connected to.
With such a configuration, it is possible to detect a minute uneven surface, that is, to detect a minute change in capacitance with high accuracy. As a result, cost reduction can be achieved without using expensive materials such as semiconductor substrates, and even if the dot pitch is reduced, the initial capacitance of each dot and the amount of change in capacitance can be increased to increase the sensitivity of the sensor. Can be improved.

A second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view of the capacitance detection type sensor according to the second embodiment (a plan view is the same as FIG. 2). The same parts as those of the first embodiment shown in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted. The apparatus shown in FIG. 8 is different from the first embodiment in that an opening 30 is provided in the passivation film 6 on the floating electrode 5.
That is, in the structure of the first embodiment (FIG. 3), the passivation film 6 on the floating electrode 5 is removed, and a part of the floating electrode 5 is exposed.

As shown in FIG. 9, the sensor unit equivalent circuit is equivalent to whether the object to be detected 7 is in contact with the floating electrode 5, that is, the switch SWx is provided on the floating electrode 5 and connected to the ground potential. Can be expressed as
That is, the capacitor 100 in FIG. 4 is replaced with an equivalent circuit of the capacitor 300 shown in FIG.
As a result, the output when the detected object 7 is sufficiently separated is the same as that in the expression (1), but when it is touched, the output is expressed as the following expression (5).

When the insulating film thicknesses similar to those of the first embodiment are used and the electrode sizes of the floating electrode 5, the drive electrode 2, and the detection electrode 3 are used, the distance between the floating electrode 5 and the detected object 7 is sufficient. The output Vo (off) = 0.48V when they are separated, and the output Vo (on) = 0.05V when the floating electrode 5 and the detected object 7 are in electrical contact, and the differential voltage ΔVo. = 0.43V output change can be obtained.
As can be seen from the relationship between the distance between the sensor surface (floating electrode 5 surface) and the detected object 7 shown in FIG. 6 and the output Vo, the output Vo of the second embodiment is abrupt in contact and non-contact. Since the output Vo changes, the detection object 7 is effective for detecting the presence or absence of the sensor surface.

Further, by using the structure shown in FIG. 8, for example, as shown in FIG. 10, the passivation film 31 can be thickened by an insulating film organic film or the like, and the surface of the passivation film 31 can be made uneven.
Here, the floating electrode 5 is provided with a protrusion 32 so that electrical contact with the detection object 7 can be obtained.
With the above-described configuration, in addition to the effects of the first embodiment, when the object 7 to be detected is a finger, the sensor surface (passivation film 31 surface) is provided with unevenness to provide a feeling such as a smooth feeling. It is possible to improve this feeling without deteriorating the sensor characteristics.

Further, as shown in FIG. 11, a ground electrode 50 is formed (provided) in each pixel portion (detection portion including the floating electrode 5), and the surface potential of the detection object 7 is fixed to the ground (earth) potential. Therefore, the voltage difference between the output Vo between the floating electrode 5 and the object 7 to be detected and the non-contact state can be increased, that is, the sensitivity can be improved. Since the potential of the object 7 to be detected can be set to the ground potential, it is possible to make it less susceptible to external radio noise.
The structure of the capacitance detection type sensor of FIG. 11 is performed with reference to FIGS. 12 and 13 are cross-sectional views taken along lines BB and CC in FIG. 11, respectively. The same components as those in FIG.

Similarly to the case where the drive electrode 2 and the detection electrode 3 are formed, the ground wiring 51 is formed between the drive electrode 2 and the detection electrode 3 by the first conductive film. Then, a contact 55 is formed in the interlayer insulating film 4, and a ground electrode 50 (ground potential) electrically connected to the ground wiring 51 by a second conductive film is provided.
The passivation film 6 on the ground electrode 50 is removed, an opening 54 is provided, and the ground electrode 50 is in direct contact with the detected object 7 so that the detected object 7 is at the ground potential.
Further, the passivation film 6 is also removed from the upper part of the drive electrode 2 and the detection electrode 3, respectively, and an opening 52 and an opening 53 are provided, respectively, so that the detected object 7 can be in direct electrical contact with each electrode. It has become.

Further, the electrode material of each electrode of the floating electrode 5, the drive electrode 2 and the detection electrode 3 and the material of the substrate 1 are not particularly limited, and as this electrode material, a transparent electrode made of ITO (indium-tin oxide) The substrate 1 can be formed of a transparent substrate such as glass or plastic.
That is, the entire capacitance detection type sensor can be made transparent, and can be formed on the display surface of the portable device as shown in FIG.
For example, as an example in which the capacitance detection type sensor S is applied to a fingerprint sensor, it can be applied to an owner authentication system of a mobile phone 26 as shown in FIG.

In recent years, it has been considered to make payments with the mobile phone 26 and the like, but by forming the capacitance detection type sensor S on the mobile phone 26, the fingerprint pressed against the capacitance detection type sensor S can be accurately detected. The owner can be correctly authenticated by checking with fingerprint data registered in advance. In FIG. 14, an example in which the display screen 26 a such as a liquid crystal of the mobile phone 26 is formed is illustrated. In this case, the column wiring 12, the row wiring 13, the drive electrode 2, the detection electrode 3, the floating electrode 5 and the like are formed of transparent electrodes, and the capacitance detection type sensor (fingerprint sensor) S is made to be a light transmission type. It is not necessary to arrange the fingerprint sensor S in a portion other than 26a, and the size can be reduced.
For the capacitance detection type sensor having the configuration shown in FIG. 7, it is also possible to use a configuration in which the detection object 7 is directly or electrically contacted with the passivation film 5B as in the configurations of FIGS. Is possible.
In each embodiment described above, at the intersection of the row wiring and the column wiring, the drive electrode extends from the row wiring, the detection electrode extends from the column wiring, and each row wiring and each column wiring is respectively It goes without saying that the row selection circuit having the I / V conversion circuit and the capacitance detection circuit may be connected.

It is a conceptual diagram which shows the structure of the equivalent circuit of the capacity | capacitance detection type sensor based on this invention. It is an enlarged plan view of a detection portion of the capacitance detection type sensor according to the present invention. FIG. 3 is a cross-sectional view taken along line AA in the first embodiment of FIG. 2. It is a conceptual diagram which shows the structure of the I / V conversion circuit 20 in the capacity | capacitance detection circuit 11 which converts the capacity | capacitance of a detection part and the displacement current which flows into this capacity | capacitance into a voltage. It is a conceptual diagram which shows the structure of the I / V conversion circuit 20 in the capacity | capacitance detection circuit 11 which converts the capacity | capacitance of a detection part and the displacement current which flows into this capacity | capacitance into a voltage. It is a graph which shows the relationship between the distance between a sensor surface and a to-be-detected object, and the output Vo of a detection result. It is a line sectional view of the detection part of the capacity detection type sensor concerning the modification of a 1st embodiment of Drawing 2. . It is a line sectional view of the detection part of the capacity detection type sensor by a 2nd embodiment of Drawing 2. It is a conceptual diagram which shows the structure of the I / V conversion circuit 20 in the capacity | capacitance detection circuit 11 which converts the capacity | capacitance of a detection part and the displacement current which flows into this capacity | capacitance into a voltage. It is line sectional drawing of the detection part part of the capacity | capacitance detection type sensor by the modification of 2nd Embodiment. It is an enlarged plan view of a detection portion of a capacitance detection type sensor according to a modification of the second embodiment. FIG. 12 is a cross-sectional view taken along line BB in FIG. 11. FIG. 12 is a cross-sectional view taken along line CC in FIG. 11. It is an external appearance perspective view which shows the mobile phone using the capacity | capacitance detection type | mold sensor of this invention as a fingerprint sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Drive electrode 3 ... Detection electrode 4, 4A, 4B ... Interlayer insulation film 5, 5A, 5B ... Floating electrode 6, 31 ... Passivation film 7 ... Object to be detected 10 ... Column selection circuit 11 ... Capacitance detection circuit 12 ... Column wiring 13 ... Row wiring 14,55 ... Contact 21 ... Capacitance (feedback capacity)
DESCRIPTION OF SYMBOLS 22 ... Operational amplifier 23 ... Switch 26 ... Mobile phone 26a ... Display screen 30, 52, 53, 54 ... Opening 50 ... Ground electrode 51 ... Grounding wiring 100, 101, 102, 103, 200, 300 ... Capacitance

Claims (5)

A capacitance detection type sensor in which row wiring and column wiring are arranged in a matrix on a substrate,
A driving electrode extending from the column wiring at the intersection of the row wiring and the column wiring;
A detection electrode paired with the drive electrode and extending from the row wiring adjacent to the drive electrode;
A floating electrode disposed on the drive electrode and the detection electrode via an interlayer insulating film,
A capacitance detection type sensor that detects a displacement current flowing from the drive electrode to the detection electrode, which changes in accordance with a distance between a detection object and the floating electrode.   2. The capacitance detection type sensor according to claim 1, wherein each of the drive electrode and the detection electrode is covered with the floating electrode except for a connection portion with a column wiring or a row wiring.   The capacitive sensor according to claim 1, wherein an insulating film is provided on the floating electrode.   4. The capacitance detection type sensor according to claim 3, wherein an opening for exposing a part of the floating electrode is provided in a predetermined portion of the insulating film. 4. The capacitance detection type sensor according to claim 3, wherein a protrusion that penetrates the insulating film and is electrically connected to the floating electrode is provided on the floating electrode.

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