JPH057640Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Technical field of invention) The present invention relates to an improvement of a coordinate input device.

(Technical background of the invention) Conventionally, scanning lines are embedded in a matrix on a tablet, a scanning signal is applied, and the magnetic field generated by the scanning signal is detected by a magnetic field detection coil of a coordinate indicating device to generate a coordinate signal. The X-Y coordinates are output to the coordinate processing circuit side, thereby sending the X-Y coordinates to the host computer side.

By the way, when X-Y coordinate signals are continuously output from the coordinate indicating device to the coordinate processing circuit, the coordinate processing circuit performs averaging processing based on the previously obtained coordinates and the currently obtained coordinates, for example. By sending out the obtained X-Y coordinates, large fluctuations in the coordinates are prevented.

(Problems in the Background Art) However, conventionally, even when the tip of the coordinate indicator is floating within a certain height area relative to the tablet surface, that is, it is wobbling, it is the same as when it is pressed against the tablet surface. Since the averaging process was performed, it was not possible to prevent small deviations from occurring in the X-Y coordinates when the coordinate pointing tool wobbled.

(Purpose of the invention) An object of the invention is to provide a coordinate input device that can smooth and input X-Y coordinates even when the coordinate pointing tool is wobbly.

(Summary of the invention) The invention is characterized in that the averaging process when the coordinate indicating device is pressed against the input plane of a tablet or the like is different from the averaging process when it is not pressed. .

(Embodiments of the invention) Hereinafter, embodiments of the invention will be described in detail with reference to the drawings.

FIG. 4 shows a coordinate input device comprising a main loop 2a, an input plane 2b with a compensation loop 3a, a driver 2 which delivers a current of constant amplitude to the main loop 2a via an oscillator 1. , a driver 3 that sends a current to the compensation loop 3a, a pickup as a coordinate indicating device having a magnetic field detection coil, an amplifier circuit 7 that amplifies the output detected by the pickup 6, a polarity discrimination circuit 8,
Detection circuit 9, sample hold amplifier 11, 1
2, a multiplexer 13, an A/D converter 14, a ROM table 15 storing compensation values, a ROM table 16 storing correction values for errors in interpolated values, and a control circuit 10. An X-direction switching circuit 4 is provided for the X-direction scanning line L of the main loop 2a, and a Y-direction switching circuit 5 is provided for the Y-direction scanning line L. The compensation loop 3a is buried so as to surround the entire main loop 2a, and one end is connected to a driver 3 that sends out a current with a predetermined amplitude in the opposite direction to the current flowing through the main loop 2a, and the other end is grounded. ing.

The ROM table 15 stores compensation values corresponding to the areas in the scanning line L and Y directions, and the corresponding compensation value ISC is called by the control circuit 10 according to the detection result of the control circuit 10. An interpolated value is calculated by the calculation means within. The ROM table 16 in which the correction values are stored is for correcting errors from the calculated interpolation values to obtain accurate coordinate positions.The ROM table 16 stores the correction values for each 0.1 mm of the interpolation values between the detected scanning lines L. is memorized. The pickup 6 is provided with a magnetic field detection coil at its tip, and the voltage generated by the magnetic field detection coil is sent as a coordinate signal to a detection circuit 9 and a polarity discrimination circuit 8 via an amplifier circuit 7. As will be described later, since the magnetic field detection coil detects the magnetic field generated in the scanning line L when a current flows through the scanning line L, the distance between the magnetic field detection coil and the scanning line L, that is, the pickup 6 The closer the distance between the coordinate signal and the scanning line L, the higher the level of the coordinate signal becomes.

Here, the operation of the coordinate input device will be explained.

The sine wave generated by the oscillator 1 is used to operate the drivers 2 and 3. In this state, control circuit 1
The driver 2 is sequentially applied only to one specific scanning line L of the switching circuits 4 and 5 specified by 0.
A current flows. On the other hand, the drive 3 supplies the compensation loop 3a with a current having an amplitude half that of the current flowing through the main loop 2a.

Now, when current flows through each scanning line L, the magnetic field generated in the scanning line L is detected by the pickup 6, and the coordinate signal output from the pickup 6 is amplified to a desired amplitude by the amplifier circuit 7. The phase of this coordinate signal is compared with the output of the oscillator 1 in a polarity determination (phase comparison) circuit 8. In other words, the polarity of the magnetic field can be detected there. and,
In the diagram of the pickup 6, if the output of the polarity discrimination circuit 8 is "H" when the left scanning line L is driven, then the right scanning line L of the pickup 6
When driven, the polarity of the detected magnetic field is reversed, so the output of the polarity discrimination circuit is also reversed to "L".

Therefore, the control circuit 10 controls X ₀ , X ₁ , X ₂ . . .
Selecting X _o and sequential scanning line L to send current,
Since the output of the polarity determining circuit 8 is inverted in the vicinity of the pickup 6, the approximate position of the pickup 6, that is, the specific segment, can be determined.

Next, the control circuit 10 selects, for example, the scanning line L(n+1) located at the left end of the segment. At this time, the coordinate signal from the pickup 6 is converted into a DC voltage by the detection circuit 9 and held as a DC voltage by the sample-hold amplifier 11.

Next, the control circuit 10 selects the scanning line L(n+3) located at the right end of the segment. In this way, skipping scanning line L(n+2) and selecting the next scanning line L(n+3) is done by dividing the segment by 1/2.
This is to improve accuracy by overlapping each time. Then, in the same manner as described above, the DC voltage obtained by the detection circuit 9 is held by the sample-hold amplifier 12.

From this state, the multiplexer 13 selects the voltage held by the sample-hold amplifiers 11 and 12 in response to a signal from the control circuit 10,
When converted into digital values by the A/D converter 14, the voltages from the scanning lines L(n+1) and L(n+3)
V _o+1 and V _o+3 are obtained.

Next, the control circuit 10 switches the switching circuits 4 and 5.
Turn off all. As a result, compensation loop 3a
Since the predetermined current flows only in the compensation loop 3a, the detection output is A/D converted by the same method as described above to obtain the voltage Vc from only the compensation loop 3a.

In addition, the control circuit 10 reads a compensation value ISC from the ROM table 15 according to the segment values in the X direction and Y direction (distance in the same direction) obtained by segment discrimination, and calculates the detected voltage V _{o +1} using the following formula. , V _o+3 ,
By substituting Vc and ISC, the interpolated value P' is calculated by the calculation means in the S control circuit 10.

P'=V _o+1 -ISC・Vc/V _o+1 +V _o+3 When the interpolated value P' is calculated in this way, the corresponding correction value is extracted from the ROM table 16 that stores correction values for correcting errors. call to obtain coordinate values that identify a position within a segment. Thereafter, the position coordinates of the segment and the coordinate values within the segment are combined by a calculation means within the control circuit, and the final X coordinate of the point position of the pickup 6 is calculated.

Similarly, calculate the Y coordinate of the point position,
During writing, two types of averaging processing, which will be described later, are performed and the calculated coordinate values are output to the host computer via the interface circuit 17.

Now, as shown in FIG. 1, the coordinate input device described above has a level determination circuit 21. This level determination circuit 21 includes an amplifier 22 for amplifying the coordinate signal from the pickup 6, and a detected device 23.
and a comparator 24. Comparator 24 outputs a pulse signal to first 2-bit shift register 25 when the coordinate signal has a level above a predetermined level. That is, as shown in FIG. 2A, the pickup 6 is at Tmm with respect to the input plane 2b.
(e.g. 15mm) when located within a height of
Since the coordinate signal has a level above the predetermined level, the comparator 24 outputs a pulse signal, and when the coordinate signal is located outside the height region of Tmm, the level of the coordinate signal is below the predetermined level, so the register 2
A reset signal is output to 5. In this way, when the height of the pick-up 6 as a coordinate indicating tool with respect to the input plane 2b is located within Tmm, the coordinate signal becomes a level higher than a predetermined level, and when the pick-up 6 is located in an area higher than Tmm, , the coordinate signal becomes a level below a predetermined level. This is input plane 2
The lower the height of the pickup 6 with respect to b, the closer the distance between the scanning line L and the pickup 6 that detects the magnetic field generated by the scanning line L, and the larger the output from the pickup 6.
In other words, the closer the pickup 6 is to the input plane 2b, the higher the level of the coordinate signal becomes.

A press determination circuit 26 is connected to the switch section at the tip of the pick-up 6. As shown in FIG. 2B, this press determination circuit 26
When the switch section is pressed against the input plane 2b and a press signal is sent out by the pull-up 6, a pulse signal is output to the second 2-bit shift register 27. When the switch section of the pickup 6 is released, a reset signal is output to the register 27.

The output sides of both registers 25 and 27 are connected to the control circuit 10.
It is connected to the arithmetic processing circuit 28 of. The arithmetic processing circuit 28 is connected to the pulse generator 2 to which the operation signal is input.
9 is connected. and the first register 25
, a second register 27, and a pulse generator 29
and the arithmetic processing circuit 28 constitute a discrimination arithmetic processing section. The arithmetic processing circuit 28 sends an operation signal to the pulse generator 29, and causes the pulse generator 29 to output shift pulses to both registers 25 and 27. Therefore, the data in both registers 25 and 27 is shifted to the arithmetic processing circuit 28. Arithmetic processing circuit 2
8 performs averaging processing based on this shifted data, as will be described later.

Next, the operation of the coordinate input device of the present invention will be explained.

As mentioned above, the pick-up 6
When the scanning signal is detected and a coordinate signal is output, this coordinate signal is amplified by an amplifier 22, converted to direct current by a detector 23, and inputted to a comparator 24. In this case, if the pickup 6 exists outside the height range of Tmm, the coordinate signal is below a predetermined level, so the comparator 24 continuously outputs a reset signal. Therefore, the first shift
The register 25 is as shown as A in FIG.
It is held at "0,0". Also, pick up 6
At the moment when the coordinate signal enters within the height of Tmm and when the coordinate signal is located within this height, the coordinate signal exceeds a predetermined level, so the comparator 24 outputs a pulse signal. Therefore, the first shift register 25, as shown by B and C in FIG.
It is held at "0,1" and "1,1". Furthermore, at the moment when the pickup 6 moves further away than Tmm, the coordinate signal becomes below a predetermined level, so the comparator 24 outputs a reset signal again. Therefore, the first shift register 25 is held at "1,0" as shown as D in FIG.

On the other hand, when the pickup 6 has not been pressed against the input plane 2b yet, the pressure determination circuit 26
outputs a reset signal since no pressure signal has been sent. Therefore, the second shift
The register 27 is, as shown as A in FIG.
It is held at "0,0". Also, pick up 6
At the moment when is pressed and when it continues to be pressed, a press signal is input, so the press judgment circuit 2
6 outputs a pulse signal. Therefore, the second shift register 27 is held at "0, 1" and "1, 1" as shown by ``b'' and ``c'' in FIG. Furthermore,
At the moment when the pressure on the pick-up 6 is released, a reset signal is input, so that the second shift register 27 is set to "1," as shown by D in FIG.
0".

The arithmetic processing circuit 28 takes in data using a shift pulse from a pulse generator 29 every time data is input to both registers 25 and 27. When the data in the first shift register 25 is "0, 0", the coordinates of the point position are calculated and averaged regardless of the contents of the data in the second shift register 27. No processing is performed. That is, when the first shift register 25 is "0,0", the second shift register 2
If 7 is "0,1", "1,0", "1,1",
For example, it is not determined that the switch part of the pickup 6 is pressed or released from another surface rather than the input plane 2b, and then no calculation is performed.

Also, the first shift register 25 is “0,
1” (at the moment of entering the height region T), the second
If the shift register 27 is "0, 0" (non-pressed state) or "0, 1" (instant of pressing), only the point position is calculated based on the movement of the cursor, etc., and then averaged. No processing is performed. In contrast, the first shift register 25 is “0,
1", and the second shift register 27 is "1, 0" (release of pressure) or "1, 1" (continuation of pressure), the switch section of the pick-up 6 has malfunctioned or malfunctioned. , and does not perform the calculation.

Further, the first shift register 25 is set to “1,
0'' (at the moment of leaving the height area T), the second shift register 27 is ``0, 0'' (non-pressed state) and ``1, 0'' (when pressed is released), Determines that coordinate input is unnecessary and stops calculation.
Also, the first shift register 25 is "1,0"
In this case, the second shift register 27 is set to “0,
1" (the moment of pressing) or "1, 1" (continuous pressing), it is determined that there is a failure, etc., and no calculation is performed.

Now, the first shift register 25 is "1,
1'' (exists in the height area T), and the second shift register 27 is ``0, 1'' (at the moment of pressing), the arithmetic processing circuit 28 determines the starting point of normal writing (pen down). The coordinates of the starting point are calculated as described above, and the obtained X-X coordinate signal is output to the host computer side. Then, when the first shift register 25 changes to "1, 1" and the second shift register 27 changes to "1, 1", the arithmetic processing circuit 28 determines that writing is in progress in the pickup 6. and the previously calculated coordinate position
Averaging processing is performed on X ₀ (Y ₀ ) and the currently calculated coordinate position X _p (Yp) based on the following averaging formula at the time of pressing.

Xout=(1/2・X ₀ )+(1/2・X _p ) Yout=(1/2・Y ₀ )+(1/2・Y _p ) The first shift register 25 is “1,1 ”, the second shift register 27 is “0,0”,
In the case of "1, 0", the arithmetic processing circuit 28 determines that the pick-up 6 is not being pressed, that is, is being operated erratically, and calculates the previously calculated coordinate position X ₀ (Y ₀ ) and the current point. The coordinate position X _p (Y _p ) calculated by
is averaged based on the following averaging formula when not pressed.

Xout=(3/4・X ₀ )+(1/4・X _p ) Yout=(3/4・Y ₀ )+(1/4・Y _p ) In this way, when the pickup 6 is not pressed, If the averaging process is performed using _a different averaging formula, that is _, an averaging formula that gives weight to the previously calculated coordinate position Even if the pickup is unstable, a stable X-Y coordinate signal can be output to the host computer side.

The averaging formula in the above embodiment is just an example, and it goes without saying that other averaging formulas may be used.
In this case as well, it is sufficient to give weight to the previously calculated coordinate position.

In this embodiment, when a microcomputer is used as the control circuit 10, flag registers corresponding to the height area status and switching status of the pickup are used inside the microcomputer, and the It is sufficient to perform each averaging process when no pressure is applied.

(Effects of the invention) According to the invention, the height level of the coordinate indicating tool relative to the input plane of a tablet or the like and the presence or absence of pressure are detected to determine whether it is a pressed writing state or a non-pressed writing state. By providing a discrimination calculation processing unit that performs averaging processing that gives more weight to the previously calculated coordinates than the averaging processing of the X-Y coordinates performed during pressure writing, the coordinate indicating tool is within a predetermined height area. Even if you wander, the coordinates almost never touch. Therefore, the coordinates can be input after smoothing.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the main parts of the coordinate input device according to the present invention, FIGS. 2A and 2B are diagrams for explaining the relationship between the position of the pickup with respect to the input plane and coordinate signals, respectively, and FIG. FIG. 4 is a diagram showing the contents of the first and second shift registers, and is an overall configuration diagram of the coordinate input device. 10...Control circuit, 24...Comparator, 2
5, 27...shift register, 26...pressure determination circuit, 28...arithmetic processing circuit, 29...control unit.

Claims (1)

[Claims for Utility Model Registration] Detects scanning signals of scanning lines arranged in a matrix on an input plane, outputs a coordinate signal according to the detection level, and outputs a pressure signal by pressing the input plane. In a coordinate input device comprising a coordinate indicating tool and a coordinate processing circuit that processes the coordinate signal and outputs the processed coordinates to a host computer or other host device, the height position of the coordinate indicating tool with respect to the input plane level determination means for determining the level of the coordinate signal and outputting a level determination signal to detect whether or not the writing state is within a predetermined height; detecting the presence or absence of the pressure signal and outputting a pressure determination signal; a pressure determination means that determines whether the coordinate indicating instrument is in a pressure writing state or a non-pressure writing state based on the level determination signal and the pressure discrimination signal, and when in the pressure writing state, the previously calculated coordinates and the current coordinates are determined. The calculated coordinates are averaged to calculate the coordinates to be output to the host device, and in the non-press writing state, the previously calculated coordinates and the currently calculated coordinates are compared to the averaging process during pressure writing. A coordinate input device comprising: a discrimination calculation processing unit that calculates coordinates to be output to the host device by performing an averaging process that gives weight to the previously calculated coordinates.