JPH11305931A - Coordinate detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform highly accurate coordinate detection even in the case that a tool force becomes weak in the middle of continuous writing and to prevent generation of a line break or the like, by continuing the same processing as a pen down state but not using the coordinate value and not outputting coordinate data in the case of detecting pen down and judging a fine pen down/up state. SOLUTION: A pen down detection part 106 detects a pen down state corresponding to the degree of contact to a digitizer surface, a fine pen down state detection part 107 detects a fine pen down/up state, and an arithmetic control part 104 transforms and computes the detected values of a contact position to position coordinates. In the case that the pen down is detected by the pen down detection part 106 and the fine pen down/up state is detected by the fine pen down state detection part 107, a host CPU 105 holds the state of a coordinate detection processing in the pen down state and inhibits the output of position coordinate data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coordinate detecting device and a coordinate detecting method using the same.

[0002]

2. Description of the Related Art In recent years, many portable information processing apparatuses that are lightweight and portable have been commercialized, and products that perform handwriting input and icon operations using a pen are increasing. Above all, regardless of the type of pen used, an inexpensive resistive pressure-sensitive digitizer that can be realized with a simple configuration is employed.

FIG. 3 shows a configuration of a resistive film pressure-sensitive digitizer. The resistive film pressure-sensitive digitizer has two upper and lower panels (301) formed of a resin film or the like facing each other, and a conductive sheet (resistive film sheet) (302) inside the panel (301) by vapor deposition or the like. Are formed to form a sandwich-like structure. In a state in which nothing is pressed (normal state), an insulating spacer (303) is arranged to form a gap so that the two conductive sheets (302) do not come into contact with each other.

Electrodes are provided at both ends of each conductive sheet, and leads are connected to the respective electrodes, and are used as terminals for applying a voltage and detecting a voltage. X,
To detect a two-dimensional position like the Y coordinate,
Electrodes are installed at both left and right ends for coordinate detection, and the other is Y
Electrodes are set at both upper and lower ends for coordinate detection. That is,
The respective electrodes are arranged so as to be orthogonal.

FIG. 4 shows a configuration of a coordinate detecting device using a conventional resistive film pressure-sensitive digitizer. FIG. 5 shows a flowchart of a conventional coordinate detection process. The sampling counter unit (40
In 8), a fixed sampling period is generated. At each sampling cycle, it is checked whether or not the digitizer (401) has been pressed (step 502). To detect the pressed state, the electrode switch (402) is set to the pen-down detection switch state, and a voltage is applied between the X-coordinate detection conductive sheet and the Y-coordinate detection conductive sheet of the digitizer. The level of the pen-down signal at that time is detected (step 503). This processing is performed by the pen down detection circuit (406).

[0006] It is determined whether or not the pen is in the pen down state (step 504).
Coordinate detection (step 506), Y coordinate detection (step 5)
07). The detection of the X coordinate is performed by applying a voltage to both ends of the conductive sheet for X coordinate detection and detecting the voltage of the Y coordinate detection surface facing the same. The obtained voltage value is converted into a digital value by an AD converter (403),
The data is converted into coordinate values by the arithmetic control circuit (404).

[0007] In the detection of the Y coordinate, a voltage is applied to the conductive sheet for Y coordinate detection, and the detection is similarly performed on the X coordinate detection surface. When the detection of both the X coordinate and the Y coordinate is completed, the data is transmitted to the host CPU (405) (step 50).
9). Then, in order to process the next coordinate data, information such as the number of times of coordinate output and data for averaging processing is stored in preparation for noise processing or the like (step 510). This process is repeated.

If the pen is determined to be in the pen-up state,
It is determined whether or not data having more than coordinates has been sent (step 513), and if it has been output, a pen-up code is sent (step 514). Then, it clears the state internally stored such as noise processing data required when the continuous pen is down, and separates it from the continuous pen down state (step 515). If you haven't sent anything before,
It returns to the idle state ((step 501)), and repeats these processes.

The conventional resistive pressure-sensitive digitizer coordinate detecting device has the following problems. Digitizer input load set value is high to prevent touch (high contact resistance)
In this case, no input is made unless a strong pressure is applied. Further, if the writing becomes slightly weaker in the middle of writing, a pen-up state occurs during the processing, and an unstable voltage may be detected at the time of coordinate detection, and abnormal coordinate data may be detected.

Further, even when a person with low writing pressure inputs or when the pen is moved at high speed, contact between the upper and lower resistive films becomes insufficient and abnormal data is detected. There is. In this case, noise coordinate data such as skipped coordinates is output or unnatural coordinates are cut off. This is a major factor in using the resistive pressure-sensitive digitizer as an input device of a pen input device, in which the coordinate detection performance is reduced and reliability is lacking.

As a method for eliminating an unstable pen-up state, there is the following technique. Japanese Patent Publication No. 6-318133 discloses a method in which the pen-up state is recognized as the pen-up state only when the pen-up state continues for a specified number of times or more. However, this is intended to eliminate chattering at the time of pen down and pen up, and cannot cope with a delicate pen down / up state. Further, since the specified number of times of the pen-up state is fixed, necessary data is discarded more than necessary, which may cause inadvertent disconnection of the line or output unstable data.

[0012]

When the set value of the input load of the digitizer is high (the contact resistance is high), if the input is not made unless a strong pressure is applied, or if it becomes slightly weaker on the way, the processing is in progress. As a result, a pen-up state occurs, an unstable voltage is detected during coordinate detection, and abnormal coordinate data may be detected.

Also, when a person with low writing pressure inputs or when the pen is moved at high speed, the contact between the upper and lower resistive films becomes insufficient and abnormal data is detected. There is. In this case, noise data such as skipped coordinates is output, or output is performed in a form such as out of coordinates. In the conventional resistive film pressure-sensitive digitizer coordinate input device, there is a problem that fine processing of the grain at the time of delicate pen down / up is not performed.

[0014]

In order to solve these problems, in the present invention, a potential change of a pen down detection signal is detected, and a subtle pen down state or a pen up state is confirmed. Also, even when the pen down detection signal is active, fluctuations in the pen down signal during sampling,
Voltage fluctuations on the XY coordinate detection surface during coordinate detection are detected, and if there is an abnormal fluctuation, it is determined that the pen is in a delicate pen-up state.
If you determine that this pen is in a subtle down / up state,
Processing is continued as in the pen-down state, but the coordinate values are not used and no coordinate data is output. Also, the pen-up code is not output.

At the time of delicate pen down / up, a means for storing various pen down information is provided, and by processing the pen as a continuous pen down state, an abnormal line break can be eliminated. In addition, the number of fine pen-up determinations can be arbitrarily set, and more detailed settings can be made in accordance with the characteristics of the digitizer.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit configuration block diagram showing one embodiment of the present invention. Reference numeral 101 denotes a pressure-sensitive coordinate detection sensor called a digitizer or a tablet. When pointing on the digitizer with a pen or finger,
It is converted into an electric quantity corresponding to the coordinate position and output as a basic coordinate value.

Reference numeral 102 denotes a switch circuit that switches to apply a voltage to each electrode of the digitizer. At the time of pen-down detection, switching is performed so that a voltage between the X coordinate detection surface and the Y coordinate detection surface is applied. At the time of X-coordinate detection, switching is performed so that a voltage is applied between the electrodes at both ends of the X-coordinate detection surface, so that a voltage corresponding to the X-coordinate position can be sent from the electrodes on the Y-coordinate detection surface to the AD converter (103). I do. At the time of Y coordinate detection, switching is performed so that a voltage is applied between the electrodes at both ends of the Y coordinate detection surface, so that a voltage corresponding to the Y coordinate position can be sent from the electrodes on the X coordinate detection surface to the AD converter (103). I do.

Reference numeral 103 denotes an AD converter. The voltage read from the digitizer is converted into digital data.
104 is an arithmetic control unit. By software processing, control of the sampling period counter (108), control of the switch (102), control of the AD converter (103), confirmation of pen-down detection, and the like are performed. In addition, arithmetic processing, correction processing, noise processing, and the like for converting the coordinate system are performed.

Reference numeral 105 denotes a host CPU. It interprets the coordinate data generated by the arithmetic control unit (104) and performs processing such as drawing on a display device and character recognition processing. 106
Is a pen down detection unit. When the operation control unit (104) switches to a pen down detection switch, a pen down signal is sent from the switch unit (102). Determine its level.

Reference numeral 107 denotes a determination unit for checking whether the pen is in a delicate pen down / up state. Reference numeral 108 denotes a sampling cycle counter unit that generates a periodic sampling time. FIG. 2 is a control sequence diagram showing one embodiment of the present invention. Step 201 is an idle state.

Step 202 is a step for determining whether or not the sampling time has been reached. That is,
Here, it is determined whether or not the sampling period notified from the sampling period counter (108) has arrived. When the sampling time has been reached, next, in step 203, the pen down is detected. On the other hand, if the sampling time has not been reached, step 20
It returns to 1 and waits in the idle state until the next sampling time arrives.

In step 203, the switch circuit (102) is switched to a pen down detection switch state to prepare for detecting the level of the pen down signal. Step 204 is a step of determining a pen down state. Here, the pen down detection unit (106)
To determine whether the pen down signal is at the pen down level. Here, if it is determined that the pen is down,
Proceeding to step 206, preparations are made to perform XY coordinate detection. On the other hand, if the pen is in the pen-up state, the process proceeds to step 214, where it is determined whether or not at least one point of coordinate data has been output during the continuation of the pen-down state up to that point. In this case, a pen-up code is output to inform the host CPU of the pen-up state. At the same time, for example, in step 210 or 212 described later, if the previous coordinate data is stored to perform noise processing or averaging processing, the internal state of the arithmetic control unit is cleared. (Step 215). On the other hand, if it is determined in step 213 that the coordinate data has not yet been output, the process returns to step 201 and enters a sampling waiting state (idle state).

Step 205 is a step of judging a subtle pen down / up state. Here, a subtle pen down / up state is detected by examining the fluctuation of the pen down signal with respect to the reference level. The details will be described later. If it is determined in step 204 that the pen is in a fine pen-up state despite the pen-down state being determined in step 204, the control unit is maintained in the pen-down state to continue the processing. Therefore, even when such a delicate pen-up state is detected, processing such as pen-up code output is not performed (step 211), and the state shifts to the idle state while maintaining the internal state of the control unit (step 212). (Step 201), it waits until the next sampling.

Step 206 is a step for detecting the X coordinate, and step 207 is a step for detecting the Y coordinate. In steps 206 and 207, three X-coordinate values and three Y-coordinate values are detected within each sampling time. Step 208 is a step of again determining a subtle pen down / up state based on the detected X coordinate value and Y coordinate value. Here, X
Voltage detection is performed a plurality of times during coordinate detection and Y coordinate detection, and it is determined whether or not the detected voltage has changed. The details will be described later.

In step 208, a subtle pen-up /
If it is determined that the pen is in the down state, as in step 205, coordinate output processing such as pen-up code output is not performed in order to cause the control unit to continue processing in the pen-down state (step 211). While maintaining the internal state (step 212), the apparatus shifts to the idle state (step 201) and waits for the next sample.

Here, the detection of the X coordinate, the detection of the Y coordinate, and the determination of the subtle pen down state performed within each sampling time are preferably performed a plurality of times. In the present embodiment, as shown in FIG. Step 209
Is a step of performing noise processing or the like on the detected X coordinate value and Y coordinate value and outputting coordinate data. For example, three X-coordinate and Y-coordinate detection values shown in FIG. 6 are averaged to output one X-coordinate data and one Y-coordinate data.

Step 210 is a step of maintaining the internal state of the control unit. Here, information necessary for continuous pen down, such as noise processing data, is stored.
In step 213, as described above, it is determined whether or not coordinate data has been output at least once or more when the pen-down state has been continued up to that time. If the coordinate data has already been output once or more, a pen-up code is output (step 214), the internal state of the control unit is cleared, and the pen-down continuation state is released (step 21).
5). On the other hand, in step 213, if there is no coordinate output yet during the pen down state, the process returns to the idle state as it is (step 201).

Next, the subtle determination of the pen down / up state will be described with reference to FIG. In the drawings, the description is made with reference to the voltage change of the Y resistance film, but the same applies to the case of referring to the voltage change of the X resistance film. In the figure, S0,
S1, S2, and S3 each indicate the start timing of one sampling time. At each sampling time, coordinate detection is performed three times. Here, Y01, Y0
2,..., Y23 indicate the Y resistance film voltage (resistance divided voltage) at the time of detection of the Y coordinate plane. Also, Y01, Y02,..., Y
23 to the high level period (for example, S0 to Y01).
Is a detection period of the X coordinate plane, and during this period, the Y resistance film voltage is at the reference level. In addition,
The pen-down signal fluctuates in conjunction with three coordinate detection timings within the sampling time. For example, the pen-down signal falls immediately before the coordinate detection period of Y11 (P0).

In FIG. 2, three steps are prepared as steps for pen-down determination. One is step 204 (pen down determination) and the other two are step 205 and step 208 (subtle pen down determination). Of these, the determination of pen down in step 204 is made by looking at the state of the pen down signal immediately before the start of each sampling time. For example, the determination of the pen down state at the sampling time starting from the sampling period S1 is performed by checking the state of the pen down signal P0. As described above, when in the pen-down state, the pen-down signal has fallen to a low level, so, for example, in the sampling period S1,
Since the immediately preceding pen down signal P0 is at low level, it is determined that the pen is down. It should be noted that once the pen down state is determined in this way, the result of this determination is considered to be valid for the entire period of the sampling time.

Similarly, subtle pen-down determination in step 205 is also performed by checking the state of the pen-down signal immediately before the start of each sampling time. That is, the pen-down signal in FIG. 2 falls sufficiently to the pen-down level when the digitizer is pressed sufficiently hard, but on the other hand, when the pressing load is not sufficient, the pen-down level is sufficient. Does not fall. In step 204, the subtle pen-down in step 205 in FIG. 2 is determined by detecting the insufficient fall level of the pen-down signal. Specifically, by comparing the level of the pen-down signal immediately before the start of each sampling period with a predetermined threshold value, it is determined whether or not the pen-down is subtle.

The detection of such a subtle pen down is as follows.
Not only a method of comparing the level of the pen-down signal immediately before the start of each sampling period with a predetermined threshold value, but also other methods may be employed as appropriate. For example, a subtle pen-down may be detected by comparing the level of the pen-down signal immediately before the start of each sampling period with the level of the pen-down signal immediately before that.

Next, a method of determining a subtle pen down in step 208 will be described. In the voltage waveform on the Y coordinate detection surface in FIG. 6, the electrode switching is performed three times within one sampling time to perform the XY coordinate detection. In the present example, the value of the Y resistance film voltage fluctuates greatly within the sampling time of the sampling period S1. (Y11, Y12, Y1
3). That is, although Y11 and Y13 are at the same level, Y12 fluctuates greatly compared to this. This is because an accurate voltage could not be read due to a delicate contact state at the timing of Y12. This information is determined as a subtle pen down state. If a fluctuation that cannot be obtained with the normal human writing speed occurs, this is determined as a subtle pen down / up state.

In the embodiment of the present invention, the switching of the electrodes in each sampling is performed three times as a subtle judgment of the pen down / up state. Next, the number of delicate pen down / up states is counted. If the delicate pen up state continues for a certain number of times or more, it is determined that the pen is up, and otherwise, the processing is continued without determining that the pen is in the up state. An example in which this is done is shown.

FIG. 7 is a block diagram of an embodiment of the present invention for counting the number of delicate pen down / up states and processing associated therewith. Reference numeral 701 denotes a pressure-sensitive coordinate detection sensor called a digitizer or a tablet.
Reference numeral 702 denotes a switch circuit for applying a voltage to each electrode of the digitizer.

Reference numeral 703 denotes an AD converter. 704 is
An arithmetic control unit. 705 is a host CPU. 7
Reference numeral 06 denotes a pen-down detection unit. Reference numeral 707 denotes a determination unit that checks whether the pen is in a subtle pen down / up state.

Reference numeral 708 denotes a sampling cycle counter. Reference numeral 709 denotes a subtle pen down / up count setting unit. This is a storage unit for setting how many times a subtle pen down is allowed. It can be set by a command or the like from the host CPU (705). Reference numeral 710 denotes a counting unit that counts the subtle pen down / up times. When a subtle pen down / up state occurs, the count is incremented.
If the pen is completely raised, it will be cleared.

Reference numeral 711 denotes a subtle pen down / up frequency comparison unit. Subtle pen down / up times are stored in memory
It is determined whether the set value has become larger than the set value stored in (709). FIG. 8 is a control sequence diagram showing the embodiment of FIG. The normal processing flow is basically the same as that of FIG. Each time the sampling time reaches (step 802), the pen down signal is confirmed (step 8).
03), it is checked whether the pen is down (step 804). Here, if the pen is in the pen-up state, the pen-down code is outputted if the pen-down has been continued and the coordinate data has been output one or more times (step 814). On the other hand, if the coordinate data has not been output yet, the idle state (step 80)
1). In these cases, the counter for counting the delicate pen down / up times is cleared (step 81).
9).

When the pen is down, it is checked whether the pen is in a subtle pen down / up state (step 805). Here, in the case of a delicate pen down / up state, the number of delicate states is counted (step 817), and it is determined whether the number is greater than a set value (step 818). If it is larger than the set value, it is determined that the pen is up, and the same processing as that performed when the pen is up in the pen down determination step 804 is performed. On the other hand, if the value is smaller than the set value, the coordinates are not output as a delicate state (step 811), and the internal state is held (step 812).

If it is not determined that the pen is in a delicate pen down state, detection of the X coordinate (step 806) and detection of the Y coordinate (step 807) are performed. Then, the subtle pen down / up state is again determined (step 808), and the position coordinates are calculated and output (step 809).

[0040]

According to the present invention, in a resistive film pressure-sensitive digitizer coordinate detecting device, when the pen pressure is weak, the change in the contact resistance between the resistive films is grasped, and the pen is completely pen-up or delicate pen-down. The state can be identified.
As a result, even if the writing pressure becomes weaker during continuous writing, optimal response is possible according to the pen down state,
Highly accurate coordinate detection becomes possible. Further, it is possible to realize a coordinate position reading device in which line breaks and the like are less likely to occur.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a coordinate detection device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of one embodiment of the present invention.

FIG. 3 is a basic configuration diagram of a resistive pressure-sensitive digitizer.

FIG. 4 is a block diagram showing a configuration of a conventional coordinate detection device.

FIG. 5 is a flowchart showing a conventional coordinate detection operation.

FIG. 6 is a waveform diagram showing a pen-down signal and a potential state of an XY electrode according to the embodiment.

FIG. 7 is a configuration diagram illustrating an operation of a pen-up standby process according to another embodiment.

FIG. 8 is a sequence diagram showing an operation of a pen-up standby process according to another embodiment.

[Explanation of symbols]

 101, 401, 701 digitizer section 102, 402, 702 digitizer electrode switching switch section 103, 403, 703 AD conversion section 104, 404, 704 calculation control section 105, 405, 705 host CPU 106, 406, 706 pen down detection section 107, 407 , 707 Subtle pen down state detection unit 108, 408, 708 Sampling cycle counting unit 301 Sheet (glass, film) 302 Conductive sheet (resistive film) 303 Spacer 709 Subtle pen down count storage unit 710 Subtle pen down count unit 711 Subtle pen down times judgment unit

Continuation of front page (72) Inventor Hiroshi Horii 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (11)

[Claims] 1. A coordinate detecting device capable of detecting a position coordinate of a contact point by touching a digitizer surface, a pen down detecting means for detecting a pen down state according to a degree of contact with the digitizer surface, and a subtle pen down / up. Providing means for detecting the state and calculating means for converting the detected value of the contact coordinate position into position coordinate data, wherein pen-down is detected by the pen-down detecting means,
When the delicate pen down / up detecting means detects a delicate pen down / up state, the state of the coordinate detection process is held in the pen down state and output of position coordinate data is prohibited. Coordinate detection device. 2. The coordinate detecting apparatus according to claim 1, wherein the subtle pen down / up state is determined by referring to the degree of the contact by the pen down detecting unit. 3. The coordinate detecting apparatus according to claim 1, wherein the subtle pen down / up state is determined by referring to a change in a detected value of the contact coordinate position. 4. A touch coordinate position is detected a plurality of times within one sampling time, and the subtle pen down / up state is detected by comparing the detected values of the coordinate positions performed a plurality of times with each other. 4. The method according to claim 3, wherein
3. The coordinate detecting device according to 1. 5. At the time of the subtle pen down / up,
5. The coordinate detecting device according to claim 1, wherein a pen-up code is not output without judging that the pen is in a pen-up state. 6. A pen-up code is output by releasing a pen-up code when pen-down detection means determines pen-up at the next sampling time after the subtle pen down / up is determined at a predetermined sampling time. The coordinate detecting device according to claim 1, wherein: 7. A pen-up code is output by releasing a pen-up code when a count value exceeds a predetermined threshold value. The coordinate detecting device according to claim 1, wherein: 8. The counting means counts the number of times the sampling time has arrived, and outputs a pen-up code to release the pen-down state when the number of arrivals exceeds a predetermined threshold value. The coordinate detecting device according to claim 7, wherein: 9. The coordinate detecting apparatus according to claim 7, wherein a threshold value to be compared with the count value of said counting means can be arbitrarily set by a command from the outside. 10. A coordinate detecting apparatus comprising: a storage unit for continuously storing information obtained in a continuation state of a pen-down operation when a pen is delicately moved up. 11. The digitizer is of a resistive film pressure-sensitive type in which when a digitizer surface is pressed, two conductive sheets come into contact with each other and a pressed coordinate position is detected as a voltage. The coordinate detecting device according to any one of claims 10 to 10.