JPH0416808B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a coordinate input device, and more particularly to a coordinate input device with improved coordinate specifying method.

``Prior Art'' In a coordinate input device, it is necessary to use a coordinate specifying method that is not affected by changes in the distance between each contact between the coordinate indicating means and the electrode wire, or by fluctuations in the power supply voltage at that time. For this reason, conventional devices, such as the coordinate input device of Japanese Patent Publication No. 53-19380, use a method of determining at least three potentials related to the contact coordinates and determining the coordinate data from the ratio to prevent errors caused by the fluctuations, etc. I'm here.

"Problems to be Solved by the Invention" However, the coordinate identification methods used in conventional coordinate input devices, including the coordinate input device described above, all have complicated procedures and require considerable man-hours and costs to design and manufacture. It was hot.

"Means for Solving the Problems" Therefore, the inventor of the present application has conducted various studies in order to solve the above problems, and as a result, the function corresponding to the magnitude of the predetermined induced pulse when the indicating means comes into contact is It was found that this can be determined from the integrated value of the magnitude of each induced pulse.

The device of the present invention is configured to realize this function, and includes means for calculating the integrated value of the magnitude of each induced pulse, and selecting a function corresponding to the magnitude of a predetermined induced pulse at that time from the integrated value. The main components are a means for comparing the magnitude of the predetermined induced pulse with the function and specifying the designated coordinates at that time, and specifying the coordinates.

"Operation" In other words, in the device of the present invention, the integrated value of the magnitude of the induced pulse in each change state of the distance between the electrode wire and the indicating means and the power supply voltage, and the magnitude of the predetermined induced pulse at that time are calculated. Find the function corresponding to the value by actual measurement or calculation and store it in a memory, etc., and then calculate the magnitude of the predetermined induced pulse to be applied at that time from the integrated value of each actual induced pulse detected when inputting the coordinates. A corresponding function is selected, and the designated coordinates are specified by comparing the magnitude of a predetermined induced pulse at that time with this function.

"Embodiments" Hereinafter, details of the coordinate input device of the present invention will be described based on illustrated embodiments. FIG. 1 shows the block configuration. Reference numeral 1 denotes a coordinate input board, on which X electrode lines X1 to Xn and Y electrodes Y1 to Yn are arranged at predetermined intervals in the x and y directions, respectively. MX and MY are x
Direction and y-direction multiplexer, switching circuit
GT, parallel address signal AD supplied from the processing unit CPU via input/output interface IQ
Decode and send each X electrode line X1 to amplifier AMP
Switch and connect the Xn and Y electrode lines Y1 to Yn. Apply scanning pulses SP1 to SPn. 2 is an input pen,
A driving pulse DP is applied to the tip 2A from the processing device CPU via the input/output interface IQ, and the tip 2A is brought into contact with the coordinate input panel 1 to specify desired coordinates. 2B is a pen switch built into the input pen 2, which is activated when the tip 2A comes into contact with the coordinate input panel 1 and moves toward the inside of the pen, and generates a pen switch signal PSW.

The amplifier AMP detects each electrode line X1- by the drive pulse DP applied to the detection tip 2A of the input pen 2.
It is amplified by the pulse IP induced in Y1-n.
ADC is an analog-to-digital converter that converts the magnitude of the amplified induced pulse IP from an analog value to a digital value DD. The switching circuit GT switches and supplies the address signal AD to the multiplexers MX and MY in accordance with the switching signal CH supplied from the processing unit CPU via the input/output interface IQ. The input/output interface IO not only transfers signals between each block and the processing unit CPU, but also
Data SD representing the coordinates indicated by the input pen 2 is sent to a data processing device (not shown) or the like.

The processing device CPU is composed of a microprocessor such as Zilog's Z80, and performs predetermined data processing using a random access memory RAM according to a program stored in a read-only memory ROM.

Next, the relationship between the magnitude of each induced pulse and its integrated value, which is a prerequisite for specifying coordinates, will be explained.

In FIG. 2, a sheet of a predetermined thickness is placed on the coordinate input panel 1, that is, the detection tip 2A and the X electrode line X1~
Set the distance d of Xn to a predetermined value d1, touch the tip 2A of the input pen 2 to each point on the
When applying DP, each X electrode line Xi−2 to Xi+
2 shows distribution curves fi−2(d1) to fi+2(d1) of the magnitude DD of each induced pulse IP induced in FIG. In addition,
Here, it is assumed that the magnitude of the drive pulse DP is constant. In the figure, the horizontal axis indicates the x-coordinate where the input pen 2 is in contact, and each point Xi-2 on the horizontal axis x
Xi+2 indicates the coordinates of each electrode line Xi-2 to Xi+2.
The vertical axis shows the output DD of the analog-to-digital converter ADC. For example, the curve fi-2 (d1) shows the output when the driving pulse DP is applied to the tip 2A of the input pen 2 at each point on the x-axis. , the digital value DD of the induced pulse IPi-2 induced in the electrode line Xi-2 is shown above the point on the x-axis. other curve fi−1
The same applies to (d1) to fi+2(d1). Also, TV (d1) in the same figure has two input pens at each point on the x-axis.
The integrated value of the digital value DD of each induced pulse IP1 to IPn generated in each electrode wire Xi-2 to Xi+2 when the electrodes are in contact with each other is shown above the point on the x-axis, and as shown in the figure, It remains almost constant even in points.

And x of each of these induced pulses IP1 to IPn
The digital value DD at each point on the axis is the pen tip 2A.
To explain only the induced pulse IPi of the electrode Xi, which increases or decreases according to the change in the distance d between the The curve fi decreases from fi(d1) to fi(d2) as shown in FIG. This change corresponds to the curve f1 representing the induced pulse of the other X electrode.
The same is true for (d1) to fi−1(d1) and fi+1(d1) to fn(d1), and as a result, the integrated value of the digital values of each of these induced pulses IPi to IPn in this case
TV also changes from TV (d1) to TV as shown in Figure 3.
(d2), and as mentioned above, according to the inventor's actual measurements, these TV(d1), TV(d2),...
TV (dx) and each curve f1 (d1) to fn at that time
(d2), f1 (d2) ~ fn (d2)...f1 (dx) ~ fn
There is a one-to-one correspondence with (dx).

Therefore, the distribution curves f1(di) to fn(di) and their integrated values for various distances di
TV(di) is determined in advance by actual measurement or calculation, and when specifying the coordinates, conversely, when specifying the desired coordinates with the input pen 2, the induced pulses IP1 to IPn of each electrode are detected. The integrated value from the size DD
Find the TV and the corresponding curve fi
(di) ~ fn(di), and a given one among them,
For example, by comparing fi(di) with the digital value DDi at that time, the coordinate x at that time can be specified.

In addition, from FIG. 3, it is considered that each of the curves f1 to n has the same shape. Therefore, in practice, a portion of the curve f for any electrode line X, for example the third
For the curve fi+1 between point xi in the figure and point xc, which is 1/2 electrode wire pitch away from there to the right, find each curve fi+1(di) and its integrated value TV(di) for various distances di. If you do this, you will be able to specify the coordinates.

That is, in synchronization with the input pen 2 being brought into contact with a certain coordinate and, for example, driving pulse DP being applied, induced pulses IP1-3 to IP1-3 to each electrode line X1-3 to X1+3 are applied to each electrode line X1-3 to X1+3 as shown in FIG. Assume that IP1+3 is detected (actually, small pulses also exist in the X electrode lines before and after IP1+3, but are ignored here). First, the integrated value TV(1) is determined from these induced pulses IP1-3 to IP1+3. As described above, the curve fi+1(1) corresponding to this integrated value TV(1) is uniquely determined. For convenience of explanation, if TV(1) at this time is TV(d1) in FIG. 3, then fi+1(d1) in FIG. 3 is obtained as a corresponding curve.

Next, since the largest induced pulse IP occurs in the X electrode line closest to the contact position of the input pen 2, the contact coordinate area A1 is determined from the number of the largest pulse IP in FIG. . Area A here
1 refers to the distance from one electrode midpoint to the next electrode midpoint; for example, for electrode Xi in Figure 3,
The area from point xb to point xc is area Ai. In addition,
When the input pen 2 is brought into contact with the electrode midpoint, for example between x1 and x1+1, IP1 and IP1+1 are at the same height, so coordinates can be specified immediately.

Next, the electrode wire second closest to the relevant contact, i.e.
A pulse of the second height is generated in the electrode wires that sandwich the contact point together with the nearest electrode wire. Therefore, depending on whether this electrode line is located to the left or right of the electrode line that produces the largest pulse IP1, it can be determined whether the coordinates of the input pen 2 are on the left or right side of the point x1. That is, when the contact occurs between point xi and point xd in Fig. 3, the second induced pulse IPi-1 is generated on the electrode wire Xi-1 to the left of the electrode wire where the maximum pulse IPi occurs. . Applying this to FIG. 4, the electrode line to the left of the electrode line producing IP1 should produce the second induced pulse.

On the other hand, when the contact occurs between point xi and point xc in Fig. 2, the second pulse IP should occur on the electrode wire Xi+1, and in Fig. 4, the electrode line producing IP1 and the electrode producing IP1+1 The lines have exactly this kind of relationship.

Then the second pulse, e.g.
The magnitude of 1+1 DD1+1 is the curve fi+1 in Figure 2.
The point xm can be found by comparing. Next, find the distance 1 between point xi and point xm. And 2
When the second pulse occurs at the electrode to the right of the electrode producing the maximum pulse IP1 (example in Figure 4), add this 1 to the coordinates of point x1, and when the second pulse occurs at the left electrode, Subtract 1 from the coordinates of point x1. This allows the specified x-coordinate to be specified. The procedure for specifying coordinates is exactly the same for the y direction.

Next, the operation of this embodiment will be explained based on this premise. First, when the input pen 2 is brought into contact with the coordinate input panel 1, the pen switch signal PSW is sent via the input/output interface IO (hereinafter, blocks whose names can be understood only by their symbols are omitted). is supplied to the CPU. In response to this signal PSW, the CPU switches the gate circuit GT to the multiplexer MX side and supplies the address signal AD "1" to the decoder. multiplexer mx
decodes this address signal AD and connects the X electrode
Connect 1 to AMP.

Next, the CPU sends a drive pulse to the input pen tip 2A.
DP is applied to the X electrode line X1, and an induced pulse IP1 is applied to the X electrode line
occurs. This pulse IP1 is amplified by the AMP, converted to a predetermined digital value DD1 according to its magnitude by the A-D converter, and supplied to the CPU via the ID. The CPU stores this value DD1 in a predetermined area of RAM. Similarly, the CPU sends address signals AD "2", "3",
. . . "n" are sequentially supplied, each time a driving pulse DP is applied to the tip 2A of the input pen 2, and the digital values DD2, DD3, . . . , DDn are sequentially stored in the RAM.

Next, the CPU integrates each digital value DD1 to DDn. Assuming for convenience that this integrated value is TV(d1) in FIG. 3, the CPU specifies a function representing the curve fi+1(d1) corresponding to this integrated value TV(d1).
The functions representing each curve, including the curve fi+1(d1), are in the form of a table of coordinate x versus digital value DD.
Assume that it is stored in ROM.

Next, the CPU determines the maximum value DD(1) from the digital values DD1 to DDn, and its induced pulse IP1
From the number of the electrode wire X1 that caused
Read the x coordinate from ROM. Next, the CPU selects the second digital value DD(2) from among the digital values DD1 to DDn.
is selected, and the value DD(2) is checked against the table of fi+1(d1) to read out the coordinate component corresponding to 1 in FIG. 3, that is, the distance Δx between the contact point and the x1. And the CPU reads the second digital value
The number of the electrode wire that generated the pulse Ip of DD (2) is
Compare with the number of the electrode wire that produced the th pulse Ip,
If it is larger than that, the coordinate component △ corresponds to the above 1
Add x to the x coordinate of x1. Moreover, if the number of the electrode wire that generated the second pulse Ip is smaller, the number is subtracted. This calculation result SD _x is the x coordinate of the contact position at that time.

CPU then gates GT multiplexer MY
The same processing is performed in the y direction, and the calculation result SD _y is sent to an external data processing device (not shown) together with the SD _x .

In addition, in the above embodiment, the tip 2 of the input pen 2
Although the case where there is a change in the distance between A and the electrode line X has been described, the present invention can be similarly applied to a case where there is a change in the magnitude of the drive pulse DP.

"Effects" As explained above, according to the present invention, coordinates can be specified using a simple method, and a coordinate input device can be obtained with low design and manufacturing costs.

[Brief explanation of drawings]

The figures show an embodiment of the coordinate input device of the present invention. Fig. 1 is a block diagram, and Fig. 2 shows the induction on the x-axis that occurs on each X-electrode line when the input pen is brought into contact with each point on the x-axis. A diagram showing the magnitude of pulses and their integrated values, Figure 3 shows the distance between the tip of the input pen and the electrode wire.
Diagram 4 showing changes in the magnitude of induced pulse IPi+1 generated in electrode wire xi+1 when d1 and d2
The figure is a diagram showing the induced pulse state that occurs in each electrode wire when the input pen is brought into contact with a certain point. X1~Xn...X electrode line, Y1~Yn...Y electrode line, MX, MY, GT...pulse detection means, ADC,
CPU, ROM, RAM...integration means, CPU, ROM
...Function selection means, driving means, CPU, ROM,
RAM... Coordinate identification means, 1... Coordinate input panel, 2
...Coordinate indicating means.

Claims (1)

[Scope of Claims] 1. A coordinate input board on which X electrode lines and Y electrode lines are arranged at predetermined intervals in the x and y directions, and coordinate indicating means that abuts desired coordinates on the input board; In a coordinate input device comprising a pulse applying means for applying a driving pulse to the coordinate indicating means, and a pulse detecting means for detecting an induced pulse induced in each of the electrodes by the driving pulse, A function representing a change in the magnitude of the induced pulse with respect to a change in the contact coordinate of the indicating means when the distance takes various values,
A memory means that stores in advance the integrated value of the magnitude of each induced pulse at that time, and in response to the contact of the instruction means, calculates an integrated value of the magnitude of each detected induced pulse at that time. a function selection means for selecting a corresponding function from among the functions in the storage means based on the integrated value; and a function selecting means for comparing the magnitude of the predetermined induced pulse with the selected function, and A coordinate input device characterized by comprising coordinate specifying means for specifying.