JPH0384616A - Coordinate signal input device - Google Patents

Abstract

PURPOSE:To shorten a coordinate detecting time by specifying a coordinate position signal rectangular to one of both axial directions based on >=2 signal ratios between parallel resistance lines and specifying the other coordinate position signal based on the resistance lines and the detection signal received from the coordinate position rectangular to the axial direction. CONSTITUTION:The position corresponding to a signal generator is specified on a tablet 2 based on the signal received from the signal generator approximate or touched to a desired position on the tablet 2, the electrode lines 3 set in the signal axial direction of the tablet 2, and the signal induced on a flat panel containing the uniform conductors provided under the lines 3. As a result, the number of terminal processes, buffer ICs, etc., can be decreased. Furthermore the signals can be processed in an extremely short time in a resistance detection system compared with a scanning system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an information input device for a single figure, character, etc., and particularly to a pen-touch information input device.

[Prior art and its problems] Various types of bench-touch information input devices have been proposed and used in the past, but most of the capacitive coupling methods apply pulses sequentially to electrode wires placed on a tablet. The pulse was detected using a signal detection pen that was electrostatically coupled to the applied electrode wire. (Tokuko Showa 52-2373
9 Chin Publication, No. 53-19494, No. 53-371
(Refer to Publication No. 63, etc.) In this state, the signal detection pen and the main body are connected by a cable, which makes it difficult to operate when inputting, and because the amplifier is housed inside the signal detection pen, there is a problem that the SIN ratio is poor due to external noise etc. There was a point. In order to improve operability, a signal detection pen without a cable, that is, a wireless type, has been proposed in Japanese Utility Model Publication No. 1983-5395 filed by the present applicant. This Japanese Utility Model Publication No. 60-5395 has a detection section that detects the signal emitted from the tablet and a control circuit that receives the radio waves transmitted from this detection section, so the wireless effect is However, the internal structure of the so-called signal detection pen became complicated, and the signal detected by the signal detection pen was processed using radio waves, so the improvement in the S/N ratio was not sufficient.

However, in either method, electrode wires are required to be placed on the tablet in at least two directions, the X-axis direction and the Y-axis direction, and other electrode wires are added depending on the situation. The large number of wire arrangements increases the cost, and the tablet becomes thick due to the stacking of electrode wires, which causes problems such as the complexity of terminal processing, the number of buffer ICs, and the speed of signal processing.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned conventional problems, and includes a flat plate having a --like conductor.

Coordinate signal input consisting of a plurality of resistance wire groups arranged in parallel at equal intervals on the plane plate via #@ edges, and a coordinate indicating rod for transmitting and receiving electrical signals to and from the plane plate and the resistance wire group. One coordinate position signal perpendicular to the axial direction is detected by the signal ratio of two or more of the parallel resistance lines, and the other coordinate position signal is detected from the coordinate position perpendicular to the resistance line and the axial direction. This paper proposes a coordinate signal input device that specifies coordinates from signals.

[Function] In the information input device of the present invention, a signal transmitted from a signal generator that approaches or comes into contact with a desired position of the tablet is transmitted between electrode wires arranged in one axis direction of the tablet and electrode wires arranged in this one axis direction. The corresponding position of the signal generator on the tablet is determined by a signal induced in a plane plate having a --like conductor placed under the electrode wire.

[Example] The present invention will be described with reference to the accompanying drawings. 1 is a tablet of the present invention, FIG. 2 is a sectional view of the tablet, FIG. 3 is an electrical block diagram of detection, and FIG. 4 is a circuit diagram of a stylus. Reference numeral 1 indicates a stylus as a signal transmitting means, and reference numeral 2 indicates a tablet as a receiving means. As shown in FIGS. 1 and 2, the tablet 2 is placed on the copper plate side of the single-sided copper clad plate 5 of the printed circuit board on the base plate 4 made of an insulating material to a sufficient thickness (preferably 10 to 20 mm).
μm) resist 6 is silk-printed, and after baking, the electrodes 41 if 3° 3, etc. are coated with silver paste or carbon.
... to be silk-printed. The post-baking process then silk-prints the resist 8 as a protective overlay. A plurality of electrode wires 3, 3. ... is a predetermined interval (preferably 5 to 6
+am) and are arranged only in the X-axis direction (see FIG. 1), and each electrode wire is connected to an analog switch 9, 10 . ......, 11
It is connected to the.

Multiple electrodes on tablet 2! 3,3. Analog switch 9,10° electrically connected to...
. , 11 are commonly connected and connected to a bandpass filter 12. Bandpass filter 12
The output terminal of is connected to the detection circuit 13, and is further connected to the buffer A.
It is output via MP15.

Analog switch 9, 10. . . . 11 is selected by a sampling pulse, and the signal of the electrode wire 3 corresponding to the selected analog switch is selected by a band pass filter (hereinafter referred to as BPF) 12 and outputs only a predetermined frequency. . The detection circuit 13 is simply composed of a diode and a capacitor, and converts the detected sine wave into direct current. Buffer AMP15 is for obtaining a predetermined output level.

The signal from the copper plate 5 of the tablet 2 is output via the BPF 16, the detection circuit g17, and the buffer 18. Also,
As shown in FIG. 4, the stylus l is opened and moved by a battery 20, and its outer periphery is covered with metal, with a metal tip 21 at the tip of the stylus l protruding. CMO as an electric circuit
A predetermined crystal oscillator 22 provides positive feedback to the inverter C (74HC04, etc.) of No. 3, oscillates a rectangular wave, and outputs a sine wave at the next stage buffer amplifier 23 and integrating circuit 24.

Next, the operation will be explained. First, when a starting switch (not shown) is turned on and the stylus l is brought into contact with point P on the tablet 2 (see FIG. 5), the electrodes 1IAp1.
Stylus 1 is attached to p, pl, p4 as shown in FIG.
Voltage V□, v approximately proportional to the distance from the metal tip 2
2. v,,v4 is induced. These induced signals are obtained as signal waveforms at points A and H in the electrical block diagram of FIG. The top three signals detected here, v2>v,>v, are converted from analog to digital to digital values D2>D,>D (D: arbitrary bit length).

For normalization, the calculation (DZ D3)/(Dz D!) is performed to obtain coordinate values. The method of calculating and processing these top three signals is disclosed in Japanese Unexamined Patent Application Publication No. 60-1999, filed by the applicant.
No. 81816. This electrode wire p1. p2
．． The coordinate value in the X-axis direction is specified from p, , p4.

Next, a method for determining coordinate values in the Y-axis direction will be explained. When the stylus 1 is on the electrode line, it can be expressed by the equivalent circuit shown in FIG. Considering that the tip of the stylus 1 slides on a uniform resistance line from the 1° point to the l2 point in Fig. 7, if the stylus 1 is placed on any point P, the voltage at the terminal end 1E will be Assuming that the impedance Ri is constant, it is given by the following equation.

vi= (Ri−v)/(Rp+Ri)Rp” (
(v - Ri)/vi) -Ri-■V: Voltage RP induced at point P: The resistance value Rρ from point P to terminal 1E is given by an inverse function of vi.

Here, Ri is assumed to be larger than the impedance Z=1/2πfC of the capacitive coupling V, where C is the coupling capacitance and f is the predetermined frequency. ■From the formula, since the resistance of the electrode wire is uniform, the resistance from RP and point P to the terminal is proportional, and R
It can be regarded as p=P−IE (distance). Here vi is copper plate 5
By taking the ratio with the reference signal obtained from and normalizing it, the R
Since p is always obtained as an inverse function of vi which is proportional to the distance, coordinate values can be obtained by converting vi from analog to digital and calculating the equation as a digital value.

Next, we will explain what happens when the stylus comes off just above the electrode wire. As shown in FIG. 8, when the stylus is placed directly above an electrode line, the signal potential of that electrode line is at its maximum. As the stylus 1 is gradually moved to the left or right, the signal potential decreases, becomes the same as the signal potential of the next electrode line at the midpoint between it and the first electrode line, and then reverses. Since the spacing between the parallel electrode lines is all equal, for example, in the dotted line range centered at P2 in FIG. pitch,
For example 0. Plot the IDI interval and find the reduction ratio with respect to the maximum potential. However, since it is symmetrical with P2 as the center, the reduction ratio data can be halved on one side, and if the interval between the electrode lines is, for example, 6nn+, the number of data will be 30 pieces.

Therefore, when creating a ROM table, the ROM in the shell is 8 bits, so the ROM data is 1 in binary notation.
The address will be O~255.

To simplify the explanation, the maximum signal is assumed to be 100, and 00Inn
The reduction ratio (e.g. %) plotted for each address is
”.Next, in Fig. 8, when point Po is the origin, specify address Pjllj at coordinate points every 61 m1, and 0.1 mn from that coordinate point.
When shifted by + units, the address is specified as "1" address per l unit.

The data at the address designated as described above is used as a divisor of the AD-converted data of the maximum potential of the signal obtained at this time to execute division. After this, since the maximum data was set to 100 above, by multiplying the result of division by 100, the situation will be exactly the same as when the stylus stylus is directly above the electrode wire 3, so treat it in the same way as vi above. We can obtain coordinates parallel to the electrode line.

[Effects of the Invention] Since the present invention has the above configuration, the number of terminal processing and buffer ICs is small, and the resistance detection method takes much less time in signal processing than the scanning method. It can be processed with This greatly reduces the coordinate detection time.

Although the signal wave has been described as a sine wave, the present invention is not limited to this, and a pulse wave may also be used, and even if the signal radiation and reception are reversed, the gist of the present invention will not be changed in any way. do not have.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 shows a tablet,
Figure 2 is a longitudinal cross-sectional view of the tablet, Figure 3 is an electrical block diagram, Figure 4 is a circuit diagram of the stylus, Figure 5 is an explanatory diagram of the tablet and stylus, Figure 6 is a waveform diagram, and Figure 7 is a diagram of the stylus. The eighth section @ describes signal detection on electrode lines, and the signal detection between electrode lines. l... Stylus, 2... Tablet 3... Electrode wire, 5... Copper plate 9
．． 10, 11... Analog switch, 12.1
6...Band pass filter AMP, 13.1
7...detection circuit,

Claims (1)

[Claims] A plane plate having a uniform conductor, a plurality of resistance wire groups arranged in parallel at equal intervals on the plane plate via an insulator, and coordinates for transmitting and receiving electrical signals between the plane plate and the resistance wire group. One coordinate position signal perpendicular to the axial direction is determined by the signal ratio of two or more of the parallel resistance lines, and the other coordinate position signal is determined perpendicular to the resistance line and the axial direction. A coordinate signal input device characterized in that identification is performed from detection signals from orthogonal coordinate positions.