JPS6097429A - Input device - Google Patents

Abstract

PURPOSE:To output accurate and stable coordinates by outputting effective up- to-date data by comparing the last data with the up-to-date data whereas two deviations of each data obtained by sampling at every coordinate are within a permissible range. CONSTITUTION:Sampling by AD conversion is performed >=2 times successively after switching to an X-coordinate detection mode, and when the difference between its maximum and minimum is within a range shown by slanting lines 36, it is decided that the contacting between a pen and a resistor sheet is stable. When the difference exceeds the range, a transient response monitoring and data collecting circuit 18 sets its transient flag 23. Similarly, detection as to Y coordinates is performed. When the flag 23 is set, the control is transferred to the rejection control circuit 31 of a sequence control circuit 19 to judges whether the cause is temporary or not, controlling the whole sequence. When the flag 23 is not set after the completion of a series of operations, it is guaranteed that data in Xphi and Yphi registers 11 and 12 are nearly accurate.

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to a device for inputting two-dimensional coordinates of a point on a flat input surface into a computer, etc. by pressing the point with a writing instrument, stylus, etc. In particular, the present invention relates to an input device that obtains coordinate data based on a voltage value generated on a resistor sheet.

(Prior Art and Its Problems) A two-dimensional coordinate device using a resistor sheet is attracting attention as an inexpensive and easy-to-operate input device that does not require a pen with a cord.

However, since this input device measures the voltage at one point within the long plane formed by a large-area resistor sheet, the output coordinates 11 may vary due to vj4 noise from human hands, etc. There was a drawback.

Therefore, by providing shield electrodes with an insulating layer above and below the resistor film that makes up the input surface, the
A method was devised to prevent noise. However, if a shield electrode is provided, the static t between the resistor film and the shield positive 4;
ar, 'j For the 1st floor, the waveform of the transient response observed after setting the X, Y coordinate detection mode (setting the 11 analog switch to the desired mode) is light 5 > jl
'H, Contact I of the contact point of the resistor film that occurs when the pen is moved in a river (it became highly dependent on resistance fluctuations).

For this reason, the output river
/) Unexpected and discontinuous coordinate values were sometimes output due to fluctuations in contact resistance.

Therefore, as a countermeasure against 11f, when an unexpected coordinate value occurs, by excluding it, a stable coordinate value is output.

An example of the conventional configuration for pasting will be explained using FIG.
, an analog switch 3, a differential amplifier 4, an AD converter 5, a pen detection circuit 6, a main arithmetic and control unit 7', and an interface circuit 8.

In the above configuration, the operation up to obtaining the data of X and Y will be explained below.

First, the analog switch 3 is set to the X coordinate detection side, and after a certain period of time (for example, a value determined by the time delay due to the capacitance between the resistor and the electrode, or the response time of the analog switch 3 and the differential amplifier 4), the AD The converter 5 converts the analog voltage corresponding to the X coordinate obtained from the resistor into digital data, and the data is sent to the data acquisition circuit 9 of the main processing and control unit 7'. The data is held in the XO register 11 via the demultiplexer 10. Next, the analog switch 3 is switched to the X coordinate detection side, and data corresponding to the Y coordinate is stored in the Y (J register 12) in the same manner as described above.

On the other hand, the data processing circuit 13 of the main arithmetic and control unit 7' converts the obtained data to a required resolution, and converts the value of the pen status register 14 in the data processing circuit 13 into
O-Boat 21. It is set according to the output of the pen detection circuit 6 supplied via the sequence control circuit 19, and data is sent to the subsequent interface circuit 8. In this data processing circuit 13, the data that has already been sent out is held in the registers XP⇠IV and YPRIV15 and 16, and when new coordinate data is stored in the XΩ and Y0 registers 11 and 12, the inter-coordinate distance discriminating circuit 17 However, xg, yΩ register 11, 12 resistor XP RI V, YP R
I V15, 164C Compare the difference (distance) with the stored data with the value set in advance as an allowable range,
If it is within the allowable range, register XP1 (1 ■■, YP
The latest data in the Xρ and Yρ registers 11 and 12 is transferred to the RIVs 15 and 16 and output as valid coordinates. However, if accurate analog voltage cannot be obtained due to light pen pressure, etc., the xg, yρ register 11,
12 data and register Xl'l are also 1■, YPRIV1
If the distance from the 5°16 data exceeds the set value,
The latest data in the XB, Yy) registers 11 and 12 is considered to be coordinate noise and is invalidated to remove the noise.

However, in the above configuration, the analog switch 3 is set to each of the X and Y coordinate detection modes, and AD conversion is performed blindly after a certain period of time has elapsed to obtain coordinate data. It was not possible to perform noise judgment using a completely analog voltage level. Therefore, since noise is determined only by comparing the distance between the coordinates of two points, it is necessary to strongly suppress noise to increase reliability, which limits the available pen speed. In addition, since the distance is always judged based on the distance from the coordinates that were sent as valid last time, if the pen speed temporarily increases and it is determined to be noise, the pen will become valid last time. Unless you approach the pressing point or lift the pen once, you cannot obtain the upper and next movable coordinates, which worsens operability. (Objective of the Invention) Therefore, the object of the present invention is to The object of the present invention is to provide a device that can remove noise in sitting images caused by unstable conditions that occur when the weather is light, and can always output stable coordinate data. Another object of the present invention is that when the pen is temporarily moved at a speed exceeding the permissible range, even if it is once determined to be coordinate noise, the speed returns to within the permissible range. Sometimes it is possible to immediately output coordinate data to improve operability.

(Summary of the Invention) In order to achieve the second object, the present invention samples a plurality of voltage values corresponding to the X and Y coordinates, and out of each data sampled for each X and Y coordinate, at least It is determined whether the deviation between the two pieces of data is within a predetermined allowable variation range, and the approximately same pressure point X,
Sample the Y coordinate in the same way to determine whether the deviation is within the allowable variation range, and only when both data are acceptable, compare the previous data and recent data and determine Φ to be valid. It is designed to output the latest data.

(Embodiments of the Invention) Details of the present invention will be explained below with reference to embodiments shown in FIG. 2 and subsequent figures.

FIG. 2 shows an outline of the coordinate input device of the embodiment, and the coordinate input device includes a resistor sheet 1, a current source 2, an analog switch 3, a differential amplifier 4, an AI converter 5, and , a pen detection circuit 6, a main arithmetic and control unit 7, and an interface circuit 8. The main arithmetic and control unit 7
FIG. 3 shows the inside of the main arithmetic and control unit re7 in more detail.
7, a data processing circuit 13, a sequence control circuit 19, etc. are prepared. Moreover, each of these circuits 13, 17, 1
8 and 19 each have functional means (circuits) which will be described later, which will become clear from the explanation of their operation below.

In the initial state, there is no input of "I" to the resistor sheet 1, and the pen flag 20 of the sequence control wholesale circuit 19 is reset. If there is any pen power from this state, the pen detection circuit 6 will output "I". No. 18 is sent to the sequence control circuit 19 via the /IJ boat 21, and the following data collection sequence starts.

By supplying the above signal, the sequence control circuit 19 first determines the state of the pen flag 20.
has been reset, so the main flag n is reset. When the main flag 22 is reset, the sequence control circuit 19 resets the transient flag of the transient response monitoring/data collection circuit 18, and the transient response monitoring/data collection circuit 18 is reset.
The data collection circuit 18 is activated to perform the first data collection. That is, the analog switch 3 is switched to the X coordinate detection side, and after approximately 9.9+n5ec has passed, AD conversion is performed n times in succession, and the digital data obtained by the AI) converter 5 is the maximum value and the minimum value. MA, X register 25, MIN as necessary through the judgment circuit 24.
Set in register 26. On the other hand, the n-time sample link data is summed by the adder 27 and held in the SUM register 4. SU after being taken as this total otaku
The contents of the M register are
(The data is transferred to the 6th register 11. On the other hand, the difference between the maximum value and the minimum value of the 11th sampling data is found by the subtraction circuit 29 and compared with the set value by the comparison circuit 30, and the difference is found to be within the allowable fluctuation range. In other words, it is determined whether the sampler data is stable and reliable.

That is, FIG. 4 shows the correspondence of actual analog voltage waveforms 7, in which waveform 34 is the voltage waveform observed at the input terminal of the Al) converter.

Now, after switching the analog switch 3 to the X coordinate detection mode at time 0, after a predetermined time (td) has elapsed,
At least two consecutive AIJs at the timing shown in
Perform sampling by conversion. When the difference between the maximum and minimum values of the series of sampling values (each point represented by a black circle in the figure) is within the set value range indicated by the diagonal line 36, the contact between the resistor sheet 1 The condition is determined to be stable. However, as shown in Fig. 5, if the contact state of the resistor sheet 1 is unstable and the difference between the maximum value and the minimum value exceeds the range of the set value 36, it may cause coordinate noise. Therefore, the transient response monitoring/data acquisition circuit 18 sets the transient flag 2 for subsequent processing.
Set 3.

Next, if you switch the analog switch 3 to the Y coordinate detection side,
Data 12 to be stored in the YO register is obtained in the same manner as described above, and if the difference between the maximum value and the minimum value is outside the allowable range, the transient flag 23 is set.

The above transient i flag 23 is the sequence secondary side 1
It can only be reset from inside the concave path 19 (1111) and cannot be reset by the transient response monitoring fist data collection circuit 18. Therefore, when detecting the X coordinate or the Y position, either the transient If the response is unstable, the transient flag 23 is set.
It is also possible to check the transient flag 23 after the series of operations for detecting the %c target is completed.

If the transient flag 23 is set because the difference between the data sampled by the comparator circuit 30 is outside the allowable range u as described above, control is transferred to the reject control circuit 31 of the sequence control circuit 19.

The rejection control circuit 31 uses the transient flag 23
Determine whether the unstable condition that caused the problem is temporary, and control the overall sequence as necessary.

As described above, after the series of operations of the transient response monitoring/data acquisition circuit 18 is completed, if the transient flag is not set, the data in the XZ and YO registers 11 and 12 is guaranteed to be almost accurate data. Ru.

After that, the main flag 22 is set in the sequence control circuit 19.
is checked, and if it is not set, the data in the XZ and YΩ registers 11 and 12 are transferred to the Xl registers 32. After transferring the data to the Yl register 33 and setting the main flag, the transient flag is reset again in the same manner as described above, and the transient response monitoring/data acquisition circuit 1
8 and performs the second data collection.

The second data collection yielded almost accurate data again.
When the Z and Yρ registers 11 and 12 are set, the main flag 22 is checked. And Xl,
If the Yl registers 32 and 33 already hold accurate data that is sufficient for Shinkazu collected last time, the main flag 22 is set, so in this case, the control
41 is)15. YΩ register 11.12 (!:XI,
The contents of the Yl registers 32, 32, ie, the coordinate data, are transferred to the distance determining circuit 17 which is a means for determining the coordinate data. This distance (l
! An appropriate known means is used for the calculation of l(, and the calculated XZ, YQ registers 1.1 and 12 data and
, Yl registers 32 and 33, that is, the distance between the two points, which is the difference between the latest coordinate data and the previously collected location (non-data), is compared with the set value by the distance discrimination circuit 17.If If this distance is greater than the set value, the sequence control circuit 19 controls the first data collection.On the other hand, if the distance is within the set value, XZ.

Data held in Y53 registers 11 and 12,
That is, the latest data is sent to the data processing circuit 3 as true data.

In the data push circuit 13, smoothing processing is performed on the data (0) in the I section, non-ζ, L, and ζ1, and the data is sent to the interlace circuit 8 at the subsequent stage, and the pen flag 20 is set and reset. When accurate coordinate data is thus output, the main flag n is set, and the sequence control circuit 19 returns the operation to the next data collection processing routine.

Therefore, if accurate coordinate data of the pen down state has been output immediately before, - the main flag 22 is
has been set, so we immediately move on to the second data collection routine. That is, in this case, the new coordinate data is X@, Yρ register 11,
When set to 12, the coordinate distance determination circuit 1 is immediately activated.
7 will work. As a result, when the pen continues to move stably, it is always judged based on the distance from the previous effective coordinates, so only one sampling is required.
There is no reduction in conversion speed.

On the other hand, even if the second data collection routine is started immediately, the contact of the resistor sheet 1 is unstable at that point.
A transient flag may be set. In such a case, the sequence control circuit 101 detects the transient flag set at a certain appropriate timing, clears the main flag, and performs subsequent data collection after the first data collection. It is designed to control the control sequence. By doing this, for example, if the pen is moved faster than the allowable speed under the tilt condition, the sampled coordinate point will be less than the set value from the coordinate point that was sent as an effect just before. Even if the pen becomes invalid due to separation, it becomes possible to output rJl and effective coordinates as soon as the pen speed returns to within the permissible range.

(Effects of the Invention) As described above, according to the present invention, it is possible to always output only accurate and stable coordinates even when the pen is manually applied with light pressure. Even if the pen is temporarily moved beyond the allowable speed wave and the sampled coordinates are not output as invalid, once the pen is determined to have a velocity within the range of 81IA, Since valid coordinates can be output immediately after the change, operability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional actual Mg example, FIG. 2 is a rough block diagram of an embodiment according to the present invention, FIG. 3 is a detailed block diagram for explaining the operation, and FIG. The 51st ν1 is a diagram showing the waveform of the voltage observed in the circuit. In the figure, 3 is an analog switch, 5 is an AI) converter,
7 is the leading 'arithmetic it mountain a1 device +': s 19 is the SeaCares fli control device r, and t% 17 is an inter-coordinate distance determination circuit.

Claims (1)

[Claims] A coordinate manual means for outputting a pressure value of 7+ corresponding to the X and Y coordinates of the pressing point on the resistor sheet, and a voltage value corresponding to the X and Y positions ;p, :lj of the coordinate input means are selected. a switching means for alternately outputting, a storage means for storing data obtained by sampling a plurality of voltage values corresponding to the X and Y coordinates, and at least two of each of the sampled data. υ) comparison means for determining whether the deviation of the data is within a predetermined permissible variation range;
By switching the switching means, approximately the same pressure point X
, and control means for sampling the voltage values of the Y coordinates a plurality of times and newly storing them in the storage means; Tomo 21 II! The ratio 1 is used to judge whether the deviation of the data in step 11 is within the range of constant measurement fluctuation or not, and only when the latest data and the previous data are both within the allowable range, the most recent data is detected. A determining means compares the accumulated values of the X and Y coordinates of the imported data and the previously imported values for each X and Y coordinate, and only when the determining means determines that the accumulated value is within a predetermined allowable fluctuation range, the latest data is compared. An input device that uses Kokichi as a % symbol to output a large number.