JP2000020229A - Conductor proximity position detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the signal processing by a conductor approach position detecting device of a capacitance coupling type and to improve the noise resistance performance, coordinate precision, and operability. SOLUTION: A voltage vibration system is constituted including a sensor panel or sensor conductor array, a shield plate, a signal process circuit, and a ground and a current, and a ground signal process of electric vibration (AC signal) received equivalently from a conductor to be detected through electrostatic coupling is performed and the process result is transmitted to a non-vibration system through an isolator 15. Here, the vibration frequency is >=200 kHz.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitive proximity type conductor proximity position detecting device, and more particularly to a human body that does not actively emit a signal and a proximity position detecting device corresponding to a finger thereof.

[0002]

2. Description of the Related Art Conventionally, as a device for detecting a proximity position corresponding to a conductor to be detected, four corners of a resistive panel are voltage-driven by an operational amplifier, and at the same time, a driving current is detected by a differential amplifier. Patent No. 1536723 as an example
There is what was disclosed in the issue. As an example of detecting a change in capacitance of a grid-like conductor of a panel including a coupling capacitance with a finger, Japanese Patent Nos.
No. 7747. Although the details are not clear as an example of detecting the impedance of the resistive panel including the coupling capacitance with the finger, see Japanese Patent No. 260398.
No. 6 discloses an example. As another example, Patent Document 18 discloses an example in which four points of a touch panel are driven by an AC voltage by a transformer and a driving current component is simultaneously applied to a differential amplifier.
There is a finger position detecting device disclosed in Japanese Patent No. 81208.

[0003]

In the above-mentioned prior art, since the concept of absorbing an electric signal from a sensor panel to a conductor to be detected such as a human body is used, the circuit configuration is complicated, and the ideal configuration is obtained. It was very difficult to achieve a typical signal process. Further, when a finger which is a conductor to be detected contacts or approaches the sensor panel surface at a plurality of points, a position where a signal detected from the sensor panel is obtained from a signal of the detection conductor is equivalent to a contact or proximity position. For example, when two fingers are in contact with each other, the center position is shown between the two points, and the work efficiency is poor unlike the position indicated by the operator.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a sensor conductor array, a shield plate,
A voltage oscillation system including a signal process circuit, a ground, and a power supply circuit is formed, and a conductor such as a human body belonging to a non-oscillation system (in the present application, a conductor capable of flowing a necessary and sufficient current is included in the conductor) A conductor proximity position detection device that processes an electric vibration (AC signal) equivalently received from the device via a capacitive coupling to a ground signal, and transmits a processing result to a non-vibration system via an isolator. A plurality of points or fingertip positions are determined based on signals obtained from the detected conductor (finger) from the array. It should be noted that in the present application, “close” means about 5 cm or less (0 cm is in contact).

[0005]

When the conductor to be detected belonging to the non-vibration system is viewed (observed / measured) from the voltage oscillation system, the measurement is performed as if the conductor to be detected is oscillating in voltage. The sensor conductor array measures the electric vibration (AC signal) received capacitively and independently from the conductor to be detected in an independent and chronological manner, thereby detecting a plurality of points, detecting a contact, or detecting a contact. It is possible to eliminate influences other than fingertips.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is not a method of measuring impedance or capacitance, but a method of detecting a voltage oscillation system based on an AC signal level equivalently received from a conductor such as a human body belonging to a non-oscillation system. A sensor conductor array arranged in a grid in the X and Y directions, an analog multiplexer for sequentially connecting the conductors of the sensor conductor array, a signal processing unit for applying an output of the multiplexer, A voltage oscillation ground circuit also connected to the signal processing unit and the multiplexer;
The voltage oscillation system oscillates voltage with the same amplitude and the same phase with respect to the ground circuit, and comprises a signal processing unit and a power supply circuit connected to the multiplexer. The non-oscillation system receives equivalently from an oscillation voltage generator and a conductor. An A / D converter that converts an AC signal to be converted into a digital value, a control unit that performs arithmetic processing on the signal value quantified by the A / D converter, and an interface with an external device. Means for recognizing a plurality of points near a conductor to be detected, such as a human body and a finger or a pen, in the conductor proximity position detection device for transferring digital or analog electrical information to and from the interface via an isolator; Is a conductor proximity position detection device that encodes and sends the code to an external device.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A detailed description of the present invention will be described below with reference to the accompanying drawings. First, the conductor approach detection device shown in FIG. 1 will be described. In this embodiment, the oscillating voltage generator 2 in the non-oscillating system 1 generates a sine wave of, for example, 460 KHz. The output is the same as the frequency 46
In order to oscillate the voltage at the same phase and the same amplitude at 0 kHz, it is connected to the ground circuit 4 in the voltage oscillation system 3 or the power supply circuit of the power supply 5.

The sensor conductor arrays 6 and 7 for detecting the X and Y directions provided on the panel surface are connected to analog multiplexers 8 and 9 for the X and Y directions. Switching is sequentially performed by a control line from the provided control unit 10 and connected to the input circuit of the signal processing unit 11 provided in the voltage oscillation system 3. This input circuit has a low input impedance (details will be described later). Therefore, the sensor conductor arrays 6 and 7 for detecting the X and Y directions vibrate similarly to the ground circuit 4 of the voltage vibration system 3.

[0009] Sensor conductor array 6 for detecting X and Y directions
And 7 are formed on the surface of a transparent glass, resin, or opaque glass epoxy substrate by coating or vapor deposition, and when the material needs to be transparent, ITO (indium tin oxide), NESA (tin oxide), etc. The opaque material is carbon or the like. The shield plate 12 is not always necessary. As described above, the voltage oscillation systems 3 all perform voltage oscillation in the same phase, but within the voltage oscillation system 3, there is no electrical oscillation between any points. Voltage oscillation system 3
Only when viewed from other than this, it can be seen that the entire system is oscillating in voltage.

When the conductor (for example, the user's finger) 13 is relatively close to the X and Y direction detecting sensor conductor arrays 6 and 7, the distance between the finger 13 and the X and Y direction detecting sensor conductor arrays 6 and 7 is increased. Has capacitance. A ground impedance (Ze) mainly due to capacitance exists between the finger 13 and ground (earth), and the ground impedance Ze is usually smaller than the impedance due to capacitance (pseudo-grounding effect). Further, the ground 14 of the non-vibration system 1 is usually connected via a capacitor or a commercial power supply line (AC100).
V, AC200V line) to ground (earth) through Z
It is AC-pseudo-grounded with an impedance lower than that of e (not shown). Therefore, the user's finger 13 usually belongs to the non-vibrating system 1. The conductive resistance of the finger 13 is several KΩ to 1
It is said to be 0KΩ.

Therefore, an oscillating potential difference is generated between the finger 13 and the sensor conductor arrays 6 and 7 for detecting X and Y directions, and a small but AC current flows due to coupling capacitance. Although the sensor conductor arrays 6 and 7 for detecting the X and Y directions are actually oscillating in voltage, the electrical phenomena can be considered macroscopically based on either of them. System 3
As a reference, the finger 13 appears to vibrate in voltage (observed / measured). Accordingly, the sensor conductor arrays 6 and 7 for X and Y direction detection receive the electric vibration from the finger 13 equivalently vibrating in voltage as an AC signal and apply it to the input of the signal processing unit 11.

The signal processing unit 11 only needs to perform single-ended ground signal processing on the AC signals equivalently received by the sensor conductor arrays 6 and 7 for detecting the X and Y directions. There is no need to perform signal processing by complicated means using differential balance, which has been conventionally performed. Normal amplification to ground, band-pass filtering, AC / DC conversion (AM detection), and the like may be performed.

The processing result output of the signal processing unit 11 is transmitted to the non-vibration system 1 via the isolator 15. The electrical information transmitted by the isolator 15 is transmitted to the control unit 10 including the A / D converter 16 and the microcomputer. The microcomputer may be provided in both the non-vibration system 1 and the voltage vibration system 3.

Next, the operation sequence of the control unit until the actual conductor proximity position is detected will be described. FIG. 2 is a sensor conductor array switching sequence. Step S1 selects one of the sensor conductors from the control unit to the analog multiplexers 8 and 9 via a control line. Step S2 is a detection target received from the selected sensor conductor. A / A
The data is digitized by the D converter 16 and stored in the memory of the control unit 10. In step S3, the control unit 10 selects all sensor conductors in the X and Y directions, determines whether the received signal is stored in the memory, and returns to step S1 to repeat the operation if the selection is not completed. If the selection of the sensor conductor is completed, the process proceeds to the next sequence.

FIG. 3 shows a sequence in which a nearby conductor (finger 13) recognizes a plurality of points. FIG. 4 is a signal explanatory diagram when the finger 13 approaches a plurality of points on the panel surface 17. After the sensor conductor array switching sequence from FIG. 2, step S4 (see FIG. 3) holds the number of received signals obtained from the sensor conductors 18 that are equal to or larger than the threshold value in the X (Y) direction. The number of received signals obtained from the sensor conductor 18 which is equal to or larger than the threshold value in the other Y (X) direction is held, and in step S6, the number of received signals in each of the X and Y directions is compared. X in step S7,
The X and Y coordinates of a plurality of points are obtained from the positions (points A and B) where the sensor conductors 18 are arranged at a threshold value or more in the Y direction. If necessary, the coordinate interpolation may be performed using the reception signals of the sensor conductors (point C) located adjacent to the sensor conductors A and B. In step S7, the plurality of points obtained above are converted into codes together with the coordinate data and output to an external device (not shown).

FIG. 5 is a sequence (S8) for recognizing that the conductor (finger 13) has come into contact with the panel surface 17. After the sensor conductor array switching sequence from FIG. 2, step S9 is performed in each of the X and Y directions. The received signal obtained from the sensor conductor equal to or larger than the threshold value is digitized and stored, and in step S10, the previous received signal obtained in step 9 is compared with the newly obtained received signal of the sensor conductor at the same position. When the received signal increases beyond the set value, it is determined that the conductor (finger 13) has touched the panel surface 17, and when the received signal is below the set value and is over the threshold value, it is determined that the contact state has been reached. If it decreases, it is determined that it is separated from the panel surface 17. In step S11, the X and Y coordinates are calculated from the received signals obtained from the sensor conductor array, and output to an external device (not shown) together with the contact information. The sudden increase in the received signal when the conductor (finger) 13 comes into contact with the panel surface 17 is that the electrostatic coupling capacitance between the sensor conductor and the detected conductor is originally inversely proportional to the distance and directly proportional to the facing area. When contacting the panel surface 17, the dielectric constant of the panel is several times greater than the dielectric constant in the air, so that the received signal suddenly increases upon contact with the panel surface.

FIG. 6 shows that the conductor (finger) 13 is
S12 to S16 are routines for recognizing the contact position of
The processing is performed as follows. FIG. 7 is an explanatory diagram of signals when the finger 13 approaches the panel surface 17. After the sensor conductor array switching sequence from FIG. 2, the step S13 digitizes and holds the received signal obtained from the sensor conductors in the X and Y directions. It is checked whether the received signals (B and B ') are substantially symmetric. If the received signal is asymmetric, the step 15 is affected by the received signal other than the finger 13 such as a palm or an arm (not shown). (Fig. 7
In the case of A ′ and B ′), the difference between the reception signals B and B ′ of the neighboring sensor conductor 18 is subtracted from the reception signal A ′ adjacent to the largest sensor conductor. In step S16, the X and Y coordinates are calculated from the received signal obtained in step S15 and output to an external device (not shown).

[0018]

As described above, a simple and excellent noise-tolerant conductor proximity position detecting device is obtained by signal processing to ground without performing complicated signal processing such as differential balance. In addition, the sensor conductors are arranged in a grid pattern in the X and Y directions, and a process of reliably identifying a plurality of conductor positions and the contact positions of the conductors on the panel surface can be performed, thereby improving operability.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a configuration of a device for detecting a proximity position of a conductor such as a finger.

FIG. 2 is an operation sequence of a control unit until a conductor position is detected.

FIG. 3 is an operation sequence of a control unit when a conductor (finger) approaches a plurality of points;

FIG. 4 is a signal explanatory diagram when a plurality of conductors (fingers) approach a panel surface.

FIG. 5 is a sequence for recognizing that a conductor (finger) has contacted the panel surface.

FIG. 6 is a routine for recognizing a contact position of a conductor (finger) on a panel surface.

FIG. 7 is an explanatory diagram of a signal when a conductor (finger) approaches a panel surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Non-vibration system 2 Vibration voltage generator 3 Voltage vibration system 4 Ground circuit 5 Power supply 6 X direction detection sensor conductor array 7 Y direction detection sensor conductor array 8 X direction analog multiplexer 9 Y direction analog multiplexer 10 Control unit (CPU) Reference Signs List 11 signal processing unit 12 shield plate 13 user's finger 14 ground 15 isolator 16 A / D converter 17 panel surface 18 sensor conductor

Claims (3)

[Claims] An electric circuit having a voltage oscillating system and a non-oscillating system, and an apparatus for detecting the proximity and proximity position of a conductor to be detected on a sensor conductor array surface belonging to the voltage oscillating system, The voltage oscillation system is driven by an oscillation voltage generator having a frequency of 200 KHz or more, and receives an AC signal equivalently by capacitive coupling with the conductor,
The sensor conductor array arranged in a grid in the X direction and the Y direction, an analog multiplexer for sequentially connecting the conductors of the sensor conductor array, a signal processing unit for applying a detection output signal of the analog multiplexer, and the signal A voltage oscillation ground circuit connected also to the processing unit and the multiplexer; and a power supply circuit connected to the signal processing unit and the multiplexer, which oscillates the voltage with the same amplitude and the same phase with respect to the voltage oscillation ground circuit. The non-vibrating system includes an oscillating voltage generator, an A / D converter for converting a received signal into a digital value, a control unit for performing arithmetic processing on a signal value digitized by the A / D converter, and an external device. Receiving digital or analog electrical information between the signal processing unit and the interface via an isolator. In the conductor proximity position detecting device to be delivered, means for recognizing a plurality of points near a conductor to be detected, such as a human body, a finger, and a pen, and the conductor to be detected encode the plurality of points and transmit the encoded points to an external device. Conductor proximity position detecting device. 2. A sensor conductor array according to an abrupt change in capacitance between a conductor to be detected such as a human body, a finger, and a pen and a sensor conductor array surface and a level of an AC signal received by the sensor conductor. 2. The conductor proximity position detecting device according to claim 1, further comprising means for recognizing the contact with the surface. 3. Each AC received by the sensor conductor array.
2. The conductor according to claim 1, further comprising means for recognizing a position of the fingertip by eliminating an influence of a received signal from a fingertip other than a fingertip in contact with a sensor conductor array surface such as a palm or an arm by a signal level. Proximity position detection device.