JPH0561594A - Digitizer - Google Patents

Abstract

PURPOSE:To provide the digitizer which can output the coordinate input of the exact input point of the digitizer to a computer or the like so as to obtain exact input information and further can improve accuracy and resolution. CONSTITUTION:A band-shaped resistor 17 is divided into plural blocks by five electrodes 16. A voltage is impressed through a switching circuit 11 to the respective blocks. Since the coordinate input information is detected for each block, a distance between the electrodes 16 can be shortened and therefore, an influence to coordinate input accuracy due to the printing nonuniformity of the band-shaped resistor 17 is prevented. Further, since reference voltage terminals 16a are provided at both terminals of the band-shaped resistor 17 so as to detect the voltage impressed to the respective blocks, error due to voltage drop caused by the pattern resistance of the electrode 16 can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called digitizer used as an input device for handwritten characters and figures, and particularly when a figure is input to a computer or only a partial area of a printed matter by a copy machine. The present invention relates to a digitizer provided with a coordinate input sheet used when specifying each coordinate input data to specify and copy.

[0002]

2. Description of the Related Art As a conventional digitizer, for example, there is a digitizer disclosed in Japanese Patent Laid-Open No. 61-104513. In this case, a uniform strip-shaped resistor is formed by applying a resistance film on an insulating substrate by using a mask, coating, printing, vapor deposition, sputtering, and the like.

Another conventional example is Japanese Patent Laid-Open No.
In the digitizer using the coordinate input sheet disclosed in Japanese Patent No. 2-184512, two coordinate input sheets 1A and 1B are provided as shown in the principle diagram of FIG.
Each of the coordinate input sheets 1A and 1B has electrodes 2 and 3 facing each other at both ends of an insulating sheet, and a surface resistance 4 is formed between the electrodes. These two coordinate input sheets 1A and 1B are vertically arranged, respectively. The electrode directions are overlapped with each other by 90 degrees, and they are used, for example, for detecting the X-coordinate position of the contact point for pressing the lower coordinate input sheet 1B and for detecting the upper coordinate input sheet 1A.

That is, when the coordinate input sheet 1A is brought into contact with an arbitrary point P in FIG. 3, a voltage 5A is applied to the upper coordinate input sheet 1A to cause the sheet 1A to move.
The partial pressure at the finger contact input point P at is extracted from the partial pressure output end 6 of the lower coordinate input sheet B as X-axis coordinate position data.

Next, by applying a voltage 5B to the lower coordinate input sheet 1B, the partial pressure at the finger contact input point P on the lower coordinate input sheet 1B is extracted from the partial pressure output terminal 7 of the upper coordinate input sheet 1A as Y-axis coordinate position data. However, the position on the XY coordinate of the finger input point P is obtained by such time division.

[0006]

However, such a conventional digitizer has a problem that it is not possible to accurately input coordinates due to printing unevenness of the strip-shaped resistor. That is, the upper coordinate input sheet 1A
Considering the partial pressure of the finger touch input point, the sheet resistance 4 between the electrodes 2 and 3
If the linearity is maintained, the finger contact input point partial pressure shows a value inversely proportional to the separation from the + electrode 2 with respect to the potential difference between the electrodes (for example, 5 V). That is, assuming that the finger input point P is at the intermediate position between the electrodes 2 and 3, it should show 2.5V.

However, in actuality, the surface resistance 4 is affected by printing unevenness and the like and does not exhibit accurate resistance linearity. Therefore, the 2.5V line is a curved line with respect to the original position of the chain line in FIG. As a result, even though the input person correctly points to the intermediate point, there are many cases in which coordinate data deviating from that point is input. This is the lower coordinate input sheet 1
The same applies to B.

The present invention has been made in order to overcome the above-mentioned drawbacks of the prior art, and it is possible to output an accurate coordinate input of an input point of a digitizer to a computer or the like so that accurate input information can be obtained. Moreover, it is an object of the present invention to provide a digitizer capable of improving accuracy and resolution.

[0009]

The digitizer of the present invention comprises:
A digitizer in which two sheets of strip resistors and stripe electrodes are laminated in a direction in which the strip resistors of each sheet are alternately orthogonal to each other, and which has a dot spacer for insulating between the sheets. It has a plurality of electrodes arranged to divide the body into a plurality of blocks, reference voltage terminals provided at both ends of the strip resistor, and a switching circuit for applying a voltage to each block. Then, the voltage applied to each block is read from the reference voltage terminal, and the detection means for detecting the input coordinates from the read voltage and the partial voltage at the input position is provided.

[0010]

In the digitizer having the above structure, the strip-shaped resistor is divided into a plurality of blocks using a plurality of electrodes, and a voltage is applied to each block through the switching circuit.
Since the coordinate input information is detected, the distance between the electrodes can be shortened, and therefore the coordinate input accuracy due to the printing unevenness of the strip-shaped resistor can be prevented.

Further, by providing the reference voltage terminals at both ends of the strip-shaped resistor and detecting the voltage applied to each block, the error due to the voltage drop caused by the pattern resistance of the electrodes can be reduced.

As a result, accurate input information can be obtained, so that accurate coordinate input information can be input to the output means such as a computer and the accuracy can be improved.

Further, by shortening the distance between the electrodes, the resolution of the digitizer can be increased by using the A / D converter having the same resolution.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the digitizer according to the present invention will be described below with reference to the drawings. FIG. 1 is a circuit block diagram showing the configuration of an embodiment of the digitizer of the present invention, and FIG. 2 is a flow chart for creating a coordinate input diagram by the digitizer shown in FIG.

The digitizer of the present invention, as shown in FIG.
Two coordinate input sheets 10A and 10B for X and Y coordinates arranged orthogonally to each other by 0 °, and the coordinate input sheet 10A,
Switching circuits 11, 12 and 13 connected to 10B, an A / D converter 14 for converting an analog signal of X and Y coordinates input from the switching circuit 12 into a digital signal, and this A
CP as detecting means connected to the A / D converter 14
It is roughly composed of U15.

The uniform resistors 17, 17 which are strip resistors of the coordinate sheets 10A, 10B are divided into four by five drive electrodes 16, and a voltage Vcc is applied between the drive electrodes. Switch circuit 11, 1
Three contact points a to d are provided. Drive electrode 16
A reference voltage terminal 16a is provided on both ends of.

The voltage application contacts A and D of the switching circuits 11 and 13 are connected so as to be supplied with a voltage Vcc (5 [V] in this embodiment), and a ground contact B for grounding,
E is provided. In addition, the switching circuits 11 and 13
Are provided with switches 11a, 11b and 13a, 13b which are opened and closed under the control of the CPU 15.

In the switching circuit 12, the input points of the coordinate input sheets 10A and 10B for detecting the positions of the X and Y coordinates by the pen or the finger are individually determined.
A switch 12a for selecting the contacts a, b, c, d for the coordinate input information from the coordinate input sheets 10A, 10B and the voltage information applied to each block under the control of the CPU 15 is provided. This is a contact for analog signal input.

Further, the coordinate input sheet 10A detects a Ly input pressing input point on the Y axis, and the coordinate input sheet 1
0B is configured to detect a pressing input point of LX width on the X axis.

Further, in the figure, 18 ... Are silver stripe electrodes.

The flow of the digitizer in this embodiment having the above construction will be described with reference to the flow chart shown in FIG. First, in step 100, the CPU 15 causes the A-open, B-open, C-a, D-a, and E-o.
pen control is performed, and the coordinate detection signal at the position where the finger is touched is set as an analog signal pressing voltage via the switching circuit 12
It is input to the / D converter 14.

In step 101, the A / D converter 1
The pressing voltage V input to V.4 is V> Vcc (5V) -0.
When it is 5V, that is, V> 5V-0.5V = 4.5 [V], the CPU 15 determines that there is a depression (YES), and proceeds to the next step 102. Also, in step S101,
When the pressing voltage V is the applied voltage Vcc [5V], V ≦ Vcc
-0.5V, that is, V≤5V-0.5V = 4.5
When it is [V], the CPU 15 judges that there is no depression (NO),
Returning to step 100, the press detection is repeated as described above.

In step 102, the coordinate input sheet 10
The block on B where the input point is located is searched. Here, the CPU 15 sets each switch to A-op.
en, B-open, C-a, D-a, E-d, and the position on the X coordinate of the input point is input as an analog signal from the a contact of the switching circuit 12 to the A / D converter 14. After being converted into a digital signal, the calculation unit of the CPU 15 performs a calculation of the formula X = Lx * (V / Vcc) to determine which block of the X coordinate the input point is.

Next, at step 103, the coordinate input sheet 1
It is searched for in which block on 0A the input point exists. Here, the CPU 15 sets each switch to A-
a, B-d, C-c, D-open, and E-open are controlled, and from the b contact of the switching circuit 12 to the A / D converter 14
After the position of the input point on the Y coordinate is input as an analog signal and converted into a digital signal, the calculation unit of the CPU 15 performs the calculation of the formula Y = Ly × (V / Vcc) to obtain the input point. Which block on the Y coordinate is determined.

Further, in step 104, the determined X
A voltage Vcc (5V) is applied to the block of coordinates. At this time, each switch is set to A-open and B by the CPU 15.
-Open, D-c, E-c, switch C first c
Connect to and read the voltage on the Vcc side of the block (VXH), then switch to d to read the voltage on the ground side (VXL), and finally switch to a and divide the voltage at the input position (VX)
Read.

In this way, when an input signal consisting of an analog signal on the X coordinate is input to the A / D converter 14, this analog signal is replaced with a digital signal and the CPU 15
To enter.

Next, at step 105, the coordinate position on the X coordinate thus input is calculated by the calculation unit of the CPU 15 using X = Xn + Lxn (VX-VXL) / (VXH-VXL), The position of the input point on the X coordinate is determined.

Next, the process proceeds to step 106, where the CPU 15
Switches each switch to A-b, B-b, C-b, D-ope
The voltage Vcc (5V) is applied to the block of the Y coordinate determined as n and E-open. Then step 107
Then, the CPU 15 first connects the switch C to a and reads the voltage (VYH) on the Vcc side of the block, then switches to b and reads the voltage on the ground side (VYL), and finally switches to c to select the input position. Read the pressure voltage (VX). The coordinate position thus input on the Y coordinate is obtained by the arithmetic unit of the CPU 15 by Y = Yn + Lyn. (VY-VYL) / (VXH-VXL), and the position on the Y coordinate of the input point is determined.

As is clear from the above description, according to the digitizer of this embodiment, the coordinate input sheets 10A and 10B are used.
The strip-shaped resistor 17 is divided into four by dividing each of the five electrodes into a plurality of blocks, and the distance between the electrodes 16, ... Accurate input information can be obtained with less influence on the coordinate input accuracy.

Further, by providing reference voltage terminals at both ends of the strip-shaped resistor and detecting the voltage applied to each block, it is possible to reduce the error due to the voltage drop caused by the pattern resistance of the electrodes.

Therefore, the coordinate input point of the accurate input point can be input to the output means such as a computer, and the resolution can be improved to about four times that of the conventional one by using the A / D converter having the same resolution as the conventional one. In addition to being able to improve the accuracy.

[0032]

As described above, according to the digitizer of the present invention, the strip-shaped resistor is divided into a plurality of blocks by disposing a plurality of electrodes, and thus the distance between the electrodes is shortened. It is possible to reduce the influence of uneven printing of the strip-shaped resistor on the coordinate input accuracy.

Further, by providing the reference voltage terminals at both ends of the strip resistor and detecting the voltage applied to each block, the error due to the voltage drop caused by the pattern resistance of the electrodes can be reduced.

Therefore, an accurate coordinate input of the input point of the digitizer can be outputted to the output means such as a computer so that accurate input information can be obtained, and further, an effect such as improvement in accuracy and resolution can be expected.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a digitizer of the present invention.

FIG. 2 is a flow chart for explaining the operation of the digitizer shown in FIG.

FIG. 3 is a principle diagram of a digitizer using a conventional coordinate input sheet.

FIG. 4 is a plan view of a conventional coordinate input sheet. It is sectional drawing of a digitizer.

[Explanation of sign]

 10A, 10B Coordinate input sheet 14 A / D converter 15 CPU (detection means) 16a Reference voltage terminal 17 Strip resistor 18 Striped electrode

Claims (1)

[Claims] 1. A digitizer having two sheets, each of which is composed of a strip-shaped resistor and a striped electrode, laminated in a direction in which the strip-shaped resistors of the respective sheets are alternately orthogonal to each other and having a dot spacer for insulating between the respective sheets. A plurality of electrodes arranged to divide the strip resistor into a plurality of blocks, reference voltage terminals provided at both ends of the strip resistor, and a voltage for each block. A switching circuit for applying the voltage, and a detection unit that reads the voltage applied to each block from the reference voltage terminal and detects the input coordinates from the read voltage and the partial voltage at the input position. Digitizer featuring.