JPS62134717A - Method and device for detecting position - Google Patents

Abstract

PURPOSE:To detect with a high accuracy an indicated position of a finger without being influenced by width and an interval of conductors, by arranging plural conductors in parallel to each other at a prescribed interval, and detecting a difference of voltages which have been induced to two adjacent conductors. CONSTITUTION:When a conductor 1d is touched with a finger, an induced voltage is generated in the conductor 1d, and in other conductors 1a-1c and 1e-1h, as well, the induced voltage of some extent is generated in accordance with its distance, therefore, in order to eliminate its influence, a difference of voltages which have been induced to two adjacent conductors is detected. That is to say, each conductors 1a-1h is connected to a differential amplifier 4, and to an output side of the differential amplifier 4, an A/D converter 6 is connected through a sample holding circuit 5, so that a converted digital data is read in a central processor (CPU) 7. To the CPU 7, a zero crossing detecting circuit 11 for detecting a zero crossing point of an induced voltage which is induced to the conductor is connected, and based on this zero crossing signal, a timing for taking a difference voltage of each conductor can be measured.

Description

[Detailed Description of the Invention] [Field of Application in Industry-1-] The present invention relates to a position detection method and device suitable for finger-touch manual tablets, etc., in which the indicated position can be directly manually determined with a finger. It is.

[Technical background of the invention 1] In conventional finger-touch type human-powered tablets.

A manual method in which a plurality of X-phase electrodes and Y-phase electrodes are arranged in a matrix, and by pressing the intersection points with a finger, for example, both electrodes are brought into contact and the position indicated by the finger is detected. According to , it is convenient to handle because it does not require a manual pen or its connection cord, but on the other hand, it has the following drawbacks. That is, since the contact area of the finger on the tablet is considerably larger than that of a manual handheld device, it is not possible to improve the resolution using one hand. Further, if an instruction is given between the electrodes, or if an instruction is made simultaneously across both electrodes, there is a high risk of erroneous input.

[Object of the Invention] This invention was made in view of the above-mentioned drawbacks of the conventional art.
The first objective is to provide a position detection method that has extremely high input resolution and can reliably detect the indicated position even if the indicated position is provided between conductors or across both cores.

In addition, another object of the present invention is: (10) a method for detecting coordinated Fe;
The object of the present invention is to provide a position detecting device with a simple configuration for performing .

[Summary of the invention] The human body contains 5011z, 60117. voltage is induced. Therefore, when you touch a certain conductor with your hand, a voltage proportional to the voltage induced in the human body is induced in that conductor. Therefore, in this invention, the position indicated by the finger is detected by placing a plurality of band-shaped conductors in ) 6 and detecting in which of the conductors a voltage is induced. By arranging a plurality of conductors in the X-axis direction and the Y-axis direction and overlapping them while electrically insulating them from each other, one coordinate human-powered device can be constructed.

[Embodiments] Hereinafter, the present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

Referring to FIG. 1, the present invention includes a plurality of 41)'-shaped conductors 18 to 1h, eight in this embodiment, arranged parallel to each other at predetermined intervals. Here, for example, if you touch a conductor 1d with your finger, an induced voltage is generated in this conductor 1d, but at the same time, an induced voltage is generated in the other conductor 1a.
A certain amount of induced voltage is generated at ~1c and 1e~1h depending on the distance. Therefore, in the present invention, in order to eliminate this influence, the difference between the voltages induced in two adjacent conductors is detected. That is, each conductor 18
~1h is connected to differential amplification (beam 4) via a pair of switching circuits 2.3. In this case, each switching circuit 2.3 is
7 switches each 2. ~27 and 31~:3, each of the switches 2I~2□ is connected to the conductor 18~IK, respectively, while the switch 3I~;37 is connected to the conductor 2
b to 2h, respectively.

An A/[) converter 6 is connected to the output side of the difference/IU+amplifier 4 via a sample and hold circuit 5.
Digital data converted by this A/[] converter 6 is read into a central processing unit (CPU) 7. 2. Each switching circuit 2, 3 is connected with a launch circuit 8, 9 that selectively controls on/off each switch, and this latch circuit 8゜5] and CIT LJ 7 are connected to each switching circuit 2, 3.
A data bus thread 13 is wired between the two. In connection with this, an address recorder 10 is connected to the CPU 7 via an address bus A I3, and this address recorder 10 writes a switch selection signal sent from CI) U7 to each latch circuit 8, 9. I'm trying to control it.

Further, a zero-crossing detection circuit 11 is connected to the CPU 7 to detect the zero-crossing point of the induced voltage induced in the conductor, and the timing of taking the differential voltage of each conductor is determined based on this zero-crossing signal. In this case, the zero cross detection circuit 11 is connected to the 8th conductor 1h, but it may be connected to any one of the 24-way conductors.

Next, the operation of the present invention will be explained with reference to FIGS. 2 and 3.

For example, if you touch the 4th body 1d of No. 4 11 with your finger,
The highest voltage is induced in this conductor 1d, and a certain amount of induced voltage is also generated in the other conductors 1a to lc and ]o to 1h depending on their distances.

FIG. 2(A) shows an example of the distribution state of the four dielectric voltages generated in each of the conductors 1a to 1h at this time, and FIG.
13) each conductor 1. The waveform of the induced voltage generated at a = 1 h is blurred. Since this induced voltage is a sine wave, if the voltage is held near the peak, the differential voltage between each induced voltage can be read with high accuracy.6 Therefore, in this embodiment, the reading Assuming that the time is 1 ms, the induced voltage is removed once 4.5 ms after the pulse is generated from the zero-cross detection circuit 1.

That is, an interrupt signal is input from the zero-crossing detection circuit 11 to the CPU 7 at the time when the induced voltage generated in the conductor crosses zero. When this interrupt signal is input manually, CI
−) U 7 is connected to each latch circuit 8 after 4,5 ms.
, 9 by sending a switch selection signal.

The voltage induced in two adjacent conductors is the difference between U and 4.
Each switching circuit 2, 3 is manually operated by IT! Let me make J+. In this case, the l-switch selection signal is written to each of the corresponding launch circuits 8 and 9 at address No. 43 from the address recorder 10, and thereby the switch 2
I and 3. ．． 2. and 3. ．． 2. And 31...

27 and 37 are cut sequentially. Figure 2 (C) shows 2
The differential voltage waveform of the induced voltage between two adjacent conductors is shown, and the phase thereof is reversed across the conductor 1d.

As described above, the differential amplifier 4 outputs the peak value of the differential voltage between each conductor. This analog voltage is held in the sample and hold circuit 5, then converted into a digital signal by the AID converter 6, and read into the CII IJ 7. FIG. 3 (Δ) is a waveform diagram representing this digital signal in analog form. In the figure, the vertical axis indicates the arrangement direction of the conductors 10 to lh, and the horizontal axis indicates the voltage. In this invention, in CI) U 7, a straight line or a predetermined curve connecting the two points where the above-mentioned difference 14 property of the city pressure changes is found, and the point where it intersects with the vertical axis (conductor arrangement axis) is specified. It is detected as the indicated position.

According to this embodiment, the I-digital signal is approximated by a straight line to detect the intersection with the vertical axis, but it may also be approximated to a predetermined curve by Lagrange's interpolation method or the like. In this way, the indicated position of the finger is detected from the voltage difference between the conductors, but according to the present invention, the resolution does not depend on the width of the conductors or the spacing between them. Namely.

For example, if you touch the edge of the conductor 1d on the side closer to the conductor 1c, the difference voltage between the conductor IC and 1d, and the voltage difference between the conductor 1d and I
Since the difference with the differential voltage between C and C becomes larger, the analog digital waveform changes as shown in Figure 3 (B), and as a result, the straight line connecting those two points intersects with the vertical axis. The points will also shift. Also.

Even if a contact is made between the conductors, the indicated position can be detected in the same way.

Hereinafter, we have explained the case where conductors of the number u are arranged in one direction, for example, in the X direction, but as shown in FIG. 2
By sandwiching 3 and aligning them in the X-Y direction, one coordinate human-powered device can be constructed. In that case, in order to further improve the detection accuracy, the polymer of the conductor arrangement 21 and 22 may be further applied to the conductor plate 251 which is connected to the ground via the electrical insulating sheet 24 at a rate of 91 tr/.

[Effects I] As is clear from the description of the embodiment described above, according to the present invention, tSi number of conductors are arranged at predetermined intervals! 1:
The difference between the voltages induced in two parallel conductors is detected, and the polarity of the difference voltage is reversed. By using the intersection point as the finger pointing position, it is not affected by the width of the conductors or the spacing between them.
It becomes possible to accurately detect the position indicated by the finger with high resolution.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing one embodiment of the position detection device according to the present invention, FIG. 2(A) is a distribution diagram showing the distribution state of induced voltage generated in each conductor, B) is a waveform diagram of the induced voltage generated in each conductor, Figure 3 (C) is a waveform diagram of the differential voltage between each conductor, and Figure 3 (A) is the differential voltage converted to a digital signal. Waveform diagram, same figure (■1
) is a digital waveform diagram corresponding to the case where the indicated position of the finger is changed, and FIG. 4 is a schematic exploded perspective view of the X-Y coordinate human power device constructed according to the present invention. In the figure, ], a ~1. h is a conductor, 2 and 3 are 1ilJ
4-%' circuit, 4 is a differential amplifier, 5 is a sample and hold circuit, 6 is a Δ/1) converter, 7 is a CI) U, 8,
9 is a latch circuit, 10 is an address recorder, and 1 is a zero-cross detector.

Claims (2)

[Claims] (1) In a detection method that electrically detects the indicated position of a finger, a plurality of conductors in which a voltage proportional to the induced voltage of the human body is induced are arranged parallel to each other at a predetermined interval, and two adjacent The difference in induced voltage between the two conductors is detected, one of the X-Y axes is set as the arrangement axis of the conductors, the other axis is set as the voltage axis of the difference voltage, and the polarity of the difference voltage is determined. A position detecting method characterized in that a position where a straight line or a predetermined curve connecting two points where . (2) In a detection device that electrically detects the indicated position of a finger, a plurality of conductors are arranged parallel to each other at a predetermined interval, and a voltage induced in the human body between adjacent conductors is detected. A differential voltage detecting means that sequentially detects the difference, an A/D converter that converts the differential voltage outputted from the differential voltage detecting means into a digital value, and a linear or predetermined An interpolation means interpolates according to a curve, and interpolation data output from the interpolation means is outputted from the conductor in a coordinate system in which one axis is the arrangement axis of the conductor and the other axis orthogonal thereto is the voltage axis of the differential voltage. 1. A position detecting device comprising: zero position detecting means for electrically detecting a zero position intersecting an array axis.