JPH0764704A - Coordinate input device - Google Patents

Abstract

PURPOSE:To prevent a fact that an erroneous coordinate input detection is executed due to a disturbance noise and undesired electrostatic capacity coupling, in the coordinate input device operated by a pen input. CONSTITUTION:Thus device is constituted so that the tip of an input pen 6 is movable in the protruding direction, and in a state that it is allowed to abut on a tablet 1 and pushed, a switch 6b is set to OFF (= a pen input operation ON). Also, when the switch 6b is ON (= the pen input operation OFF), a resistance 6c is inserted so that the input impedance to a peak detecting part 10 is lowered. Moreover, the peak detecting part 10 compares a supplied coordinate detection signal with a threshold value Vth, and only in the case of exceeding it, a peak detecting signal is outputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device suitable for a device such as a digitizing tablet in which a pen-type detecting conductor means is brought into contact with a tablet to input a coordinate position.

[0002]

2. Description of the Related Art For example, Japanese Unexamined Patent Publication No. 2-255911,
As seen in Japanese Patent Laid-Open No. 4-205020,
There is known a coordinate input device which detects an input coordinate by using an electrostatic coupling method for an XY matrix display. In such a coordinate input device, a stylus pen is used as a detecting conductor, and the stylus is used as a pointing device to abut on an arbitrary point on an XY matrix display (display-integrated tablet). Or trace the stylus pen as if drawing a picture from that state.

In an XY matrix display, a detection scan signal is sequentially applied to each electrode in the X direction and each electrode in the Y direction. At that time, capacitive coupling between the stylus pen and the tablet causes stylus pen. The scanning voltage is applied to the stylus pen, and the coordinate detection signal is extracted from the stylus pen. Therefore, if the peak point of the coordinate detection signal based on the capacitive coupling is detected and the X electrode and the Y electrode that are scanned at the time of detecting the peak point are discriminated, the tablet on which the stylus pen is in contact is detected. It is possible to detect the X-Y coordinates at.

[0004]

By the way, in the coordinate input device utilizing such capacitive coupling, the voltage applied to the pen tip of the stylus pen via the capacitive coupling is applied to the voltage detecting section, that is, the stylus. The input impedance on the peak detector side must be set high in order to hold the peak detector supplied with the coordinate detection signal from the pen for a certain period until the detection is completed.

However, if the input impedance is set to be high, there is a problem in that, when an erroneous coordinate detection signal is generated due to disturbance noise, the coordinate input may be erroneously detected.

In addition, even if the stylus pen is not completely brought into contact with the tablet, a coordinate detection signal due to capacitive coupling is attracted when the stylus pen is slightly separated, and the peak detection unit If the input impedance on the side is set high, this will be detected as an input.
Therefore, the coordinate input may not be made by the user.

For example, considering the case of performing an operation of selecting (clicking) two points apart from each other on the tablet with a stylus pen, in order to click the next point after the stylus pen is brought into contact with the first point. When moving the stylus pen, the stylus pen has to be separated from the tablet sufficiently, and the usability is poor. Alternatively, there is a problem in that erroneous detection (for example, coordinates on the locus from the first point to the second point is input) due to the fact that this is not sufficiently separated from the tablet. This is extremely inconvenient especially when performing input that requires fine pen operation such as character input.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in a coordinate input device using a pen-shaped detecting conductor means, disturbance noise and unnecessary electrostatic capacitance coupling are caused. An object of the present invention is to prevent erroneous coordinate input, and to improve the operability and reliability of the coordinate input device.

That is, a tablet in which the X electrodes driven by the scanning signal output from the X electrode driving means and the Y electrodes driven by the scanning signal output from the Y electrode driving means are arranged in a matrix, and the tablet is provided. Detection conductor means for outputting a scanning signal as a coordinate detection signal by capacitive coupling when the detection end is brought into contact with the detection end portion, and peak detection of the coordinate detection signal output from the detection conductor means. Coordinate detecting control means for detecting the coordinates of the contacting detection conductor means on the tablet based on the drive timing by the X electrode drive means and the Y electrode drive means and the peak detection timing by the peak detection means. In the coordinate input device including and, the detecting conductor means (stylus pen) is
The detection end portion has a first position biased in the protruding direction,
It is movable between a second position retracted from the first position, and when the detection end portion is at the first position, the peak of the coordinate detection signal from the detection conductor means is reached. The input impedance to the detection means is reduced.

The peak detecting means is configured to compare the coordinate detecting signal output from the detecting conductor means with a predetermined threshold value and detect the peak value based on the comparison output.

[0011]

The second end of the detection conductor means (stylus pen) is biased in the projecting direction at the detection end, and the second position is detected.
By making it movable between the positions, the ON / OFF switch is formed in the detection conductor means, and the switch is turned off when the detection conductor means is in contact with the tablet means and the detection end is pressed. State. Then, when the detecting conductor means is separated from the tablet, that is, when the switch is at the first position in the biasing direction and the switch is on, the input impedance to the peak detecting means is lowered. By doing so, the detection input level of the erroneous coordinate detection signal generated by disturbance noise or the like can be lowered, and erroneous detection can be prevented. For example, when the switch is turned on, between the detecting conductor means and the peak detecting means, through a resistor having a low resistance value or directly,
It can be realized by connecting to the ground.

With respect to the peak detection means, the supplied coordinate detection signal is compared with a predetermined threshold value, and peak timing detection is performed only when the threshold value is exceeded, for example. It is possible to more accurately identify and detect a correct coordinate input and an incorrect coordinate input due to noise or the like.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the coordinate input device of the present invention will be described below with reference to FIGS. In this embodiment, a thin film EL (electroluminescence) matrix tablet is used as the display-integrated tablet, but an FED type display-integrated tablet can also be used as a coordinate input device as described later. It is a thing.

FIG. 1 shows the configuration of the coordinate input device of this embodiment. Reference numeral 1 denotes a thin film EL matrix tablet (hereinafter, simply referred to as a tablet). This tablet 1
X electrodes (x ₁
~x _m), and Y electrodes to perform vertical scan arranged in the row direction (y ₁ ~y _n) are arranged in a matrix.

Each X electrode (x _{1 to} x _m ) is connected to the X scan driver 2, and the X scan driver 2 controls each X electrode (x _{1 to} x _m ) at a predetermined timing under the control of the driver controller 4. A scanning voltage is applied to the scanning voltage. The Y electrode (y ₁ ~y _n) is connected to the Y scan driver 3, Y scan driver 2 scans for each Y electrode (y ₁ ~y _n) at a predetermined timing under the control of the driver controller 4 Apply voltage. Reference numeral 5 denotes a CPU that performs image display scanning control and an input coordinate detection operation from a peak detection signal as described later.

Reference numeral 6 denotes a stylus pen for inputting coordinates by the capacitive coupling method by bringing the detection end portion (pen tip) 6a at the tip into contact with the tablet.
Reference numeral b is a switch provided inside the stylus pen 6, and reference numeral 6c is a resistor having a considerably low resistance value.

Reference numeral 7 is a resistance of, for example, about 1 to 10 MΩ, and when the switch 6b is off, the output (coordinate detection signal) of the differentiation circuit formed by the capacitance between the pen tip 6a and the tablet 1 is used. It is in a high impedance state.

Reference numeral 10 denotes an example of a peak detecting section for performing peak detection on the coordinate detection signal output from the stylus pen 6 and supplying the peak detection signal D _P to the CPU 5. The peak detection unit 10 includes an amplifier 11 having an integration function, a comparison circuit 12, a differentiation circuit 13, a second comparison circuit 14, and an AND circuit 15.

The pulse component of the coordinate detection signal from the stylus pen 6 is removed via the amplifier 11 and supplied to the first comparison circuit 12. Further, the threshold voltage V _th set to a predetermined value is supplied to the first comparison circuit 12. Further, the output of the amplifier 11 is supplied to the differentiating circuit 13 and further to the second comparing circuit 14. The outputs of the first comparison circuit 12 and the second comparison circuit 14 are supplied to the AND circuit 15 to detect the peak point.

The display operation and the coordinate input operation of the tablet 1 of this coordinate input device will be described with reference to FIGS. FIG. 4 shows each of the X and Y electrodes (x ₁ to X) of the tablet 1 executed by the X scan driver 2 and the Y scan driver 3.
shows the x _m) scanning timing waveform (y ₁ ~y _n).

As shown in FIG. 4, the period for one image frame is divided into a display period for actually performing a display operation, and a Y coordinate detection period and an X coordinate detection period for responding to coordinate input.

During the display period, the Y scan driver 3 operates for each Y
The electrode (y ₁ ~y _n), by applying a sequential scanning voltage as shown in FIG. 4 (a) ~ (c) , to perform a scan of the vertical side. That is, voltage is applied line by line from the Y electrodes y ₁ to y _n in accordance with the vertical / horizontal synchronization signal.

On the other hand, the X scan driver 2 is provided for each X
The driver controller 4 for the electrodes (x _{1 to} x _m ).
Based on the display data supplied from FIG.
As shown in (f), a voltage is applied to each electrode (x _{1 to} x _m ) within each scanning period of the Y electrodes y _{1 to} y _n . That is, X corresponding to a display pixel on a certain Y electrode (horizontal line)
A voltage is applied to the electrodes.

Therefore, during each scan of the Y electrodes y _{1 to} y _n , the pixel intersecting the X electrode to which the voltage is applied is
The electric field generated by the X electrode and the Y electrode causes the phosphor to emit light, and a display operation is performed. 4 (g) to (l) show Y
The scanning period of the electrodes y ₁ and y ₂ is expanded to show the scanning timing from the X electrode x ₁ to the X electrode x _m .

When such a display period ends, the operation as the Y coordinate detection period is performed. The Y-coordinate detection period and the subsequent X-coordinate detection period are periods for detecting coordinate input due to contact of the stylus pen 6 with the tablet 1. First, in the Y coordinate detection period, the Y scan driver 3 sequentially applies the detection voltage to the Y electrodes y _{1 to} y _{n in the} same manner as the scan voltage as shown in FIGS. 4A to 4C. . Therefore, when the nib 6a of the stylus pen 6 is in contact with a certain point on the tablet 1, the capacitance between the stylus pen 6 and a certain Y electrode corresponding to that position and the vicinity of the Y electrode. The stylus pen 6 is joined.
Then, the detection voltage is dielectricized to obtain a voltage output as a coordinate detection signal.

Also, during the X coordinate detection period, the X scan driver 2 operates on each of the X electrodes x ₁ to x as shown in FIGS.
The detection voltage is sequentially applied to x _m . Therefore, the nib 6 of the stylus pen 6 is placed at a certain point on the tablet 1.
When a is in contact, capacitive coupling is performed between the stylus pen 6 and a certain X electrode corresponding to that position and the X electrode in the vicinity thereof, and the stylus pen 6 applies the voltage to the X electrode. The detected voltage is output as a coordinate detection signal.

In FIG. 5, the horizontal axis indicates the position in the X or Y direction, and the vertical axis indicates the capacitance Ci. In reality, the capacitance distribution is relative to the contact position of the stylus pen 6 in FIG. Therefore, the voltage output along the curve is output from the stylus pen 6 during the scanning period of the Y electrode (or X electrode) adjacent to a certain Y electrode (or X electrode). Will occur.

FIG. 6 shows the Y coordinate detection operation when the stylus pen 6 is brought into contact with a position corresponding to the Y electrode y ₃ , for example. According to the capacitance distribution as shown in FIG. 5, for example, as shown in FIG.
In the scanning period (T _{1 to} T ₅ period) of the detection voltage of the Y electrodes y _{1 to} y ₅ shown in (a), the voltage output as shown in FIG. 11
Will be obtained from In addition, in FIG.
The points having the signal waveforms of (b) to (f) are shown as (b) to (f), respectively.

Here, in the peak detection section 10 to which such a coordinate detection signal is supplied, this coordinate detection signal is first input to the comparison circuit 12 via the amplifier 11 and compared with the threshold value V _th . On the other hand, the waveform obtained by differentiating the signal of FIG. 6 (b) is as shown in FIG. 6 (c). The output waveform of the first comparison circuit 12 obtained by clipping the waveform of FIG. 6B with the threshold voltage V _th is as shown in FIG. 6D. Further, when the waveform of the load signal of FIG. 6 (c) is output from the second comparison circuit 14 (FIG. 6 (e)) and the logical product of the waveforms of FIG. 6 (d) (e) is taken, Figure 6
An output signal showing a peak point is obtained as in (f).

The peak detection signal D _P is supplied to the CPU 5 by detecting the timing of pulse generation shown in FIG. 6 (f) by the scanning clock. And CPU5
Then, by discriminating the Y electrode which is scanning in the period corresponding to the timing when the peak detection signal D _P is supplied, the Y electrode at the position where the stylus pen 6 is in contact,
That is, the Y coordinate can be determined. The same applies to X-coordinate detection.

As described above, the Y coordinate as the input position is detected during the Y coordinate detection period, and the X coordinate as the input position is detected during the X coordinate detection period. The coordinates will be input.

Here, the structure of the stylus pen 6 is shown in FIG.
This will be described with reference to FIG. FIG. 2 shows a part of the pen tip 6a of the stylus pen 6, where 61 is a tip conductor that serves as an actual pen tip, and 62 is a partition plate that partitions the internal space of the stylus pen 60. The tip conductor 61 is housed in a housing space 63 formed by the partition plate 62.

A spring 64 is arranged between the partition plate 62 and the tip conductor 61. Therefore, the tip conductor 61 is disposed in the storage space 63 from FIG.
It is movable to the state of (b), and is normally in the state of FIG. 2 (b) by the urging force of the spring 64.

The states of FIGS. 2 (a) and 2 (b) viewed from the outside of the stylus pen 6 are as shown in FIGS. 3 (a) and 3 (b), that is, the pen tip moves in and out like a switch. Become.
Then, normally, the state shown in FIG. 3B is obtained, but when the pen tip is pressed, the tip conductor 6 is pressed as shown in FIG. 3A.
1 is configured to retract.

Further, the tip conductor 61 has an electrical contact 6
5 is provided, and a contact 66 is formed inside the housing of the stylus pen 6 so as to correspond to the contact 65 toward the storage space 63 side. Then, as shown in the figure, the contacts 65 and 66 are in contact with each other in the state of FIG. The contacts 65 and 66 are the switches 6 shown in FIG.
b will be formed. The contact 66 is the resistor 6c
Grounded through.

When inputting coordinates using the stylus pen 6 as described above, the tip conductor 61, which is a pen tip, is brought into contact with the tablet 1 as shown in FIG. Contact 65 and contact 66
Is released, and the switch 6b is turned off. Therefore, the coordinate detection signal output from the stylus pen 6 by capacitive coupling is peaked in a high-impedance state via the differential circuit formed by the capacitance between the stylus pen 6 and the resistor 7 shown in FIG. It is supplied to the detection unit 10.

This state is shown in FIG. 7 as a waveform model. If a voltage as shown in FIG. 7A is applied to the X electrode or the Y electrode corresponding to the position where the stylus pen 6 is in contact, the coordinate detection signal input to the peak detection unit 10 is as shown in FIG. It becomes like (b). Then, this signal is output from the amplifier 11 and converted into the signal of the curve shown in FIG. That is, it is the signal shown in FIG.

However, when the stylus pen 6 is separated from the tablet 1 (that is, in the off state in which the coordinate input is not performed), the tip conductor 61 is maximally projected by the biasing of the spring 64 as shown in FIG. 2B. And contact 65,
66 contacts and the switch 6b is turned on.

Then, the resistor 6c having a lower resistance value is inserted in parallel in the differentiating circuit formed by the electrostatic capacity and the resistor 7, whereby the input impedance to the peak detecting section 10 becomes low. Therefore, if the stylus pen 6
Even if is slightly separated from the tablet 1, erroneous coordinate input is not performed.

For example, this state is shown in FIG. 8 similarly to FIG. If the stylus pen 6 is slightly separated from the tablet 1, capacitive coupling will occur to some extent between the X electrode or the Y electrode and the tip conductor 61, so that the X electrode close to the position of the stylus pen 6 or When the voltage is applied to the Y electrode, the stylus pen 6 outputs a coordinate detection signal. However, in this case the resistance 6
Since c is inserted, even if the voltage of FIG. 8A is applied to the X electrode or the Y electrode, the peak detection unit 1
The coordinate detection signal input to 0 has a waveform as shown in FIG. 8B through a differentiating circuit having a small time constant. Therefore, the signal output from the amplifier 11 has an extremely low voltage as shown in FIG. 8C, and the waveform of FIG. 6D cannot be obtained.

Of course, even if disturbance noise is mixed for some reason with the tablet 1 completely separated from the stylus pen 6, the signal from the stylus pen 6 is supplied to the peak detector 10 in a low impedance state. Further, since it is supplied to the peak timing detection circuit 13 after being compared with the threshold value V _th , it is not erroneously determined that the coordinate is input.

Therefore, as the coordinate input device of this embodiment,
In addition to eliminating false input detection due to disturbance noise,
Even when the stylus pen 6 is moved while being kept close to the tablet 1, erroneous coordinate input determination is not performed. Then, even if the stylus pen 6 is moved while being brought close to the tablet 1, there is no problem,
The input operability will be significantly improved.

Although the resistor 6c is inserted when the switch 6b is turned on in this embodiment,
Instead of providing the resistor 6c, the switch 6b may be turned on so that the resistor 6c is directly grounded.

Further, the threshold value V _th by the threshold generator 14 is made variable, but this allows accurate identification of the erroneous input due to noise or the like and the original coordinate input as described with reference to FIGS. 7 and 8. It is intended to be finely adjusted.

Further, as the biasing member of the tip conductor 61, various biasing members such as a leaf spring can be used in addition to the spring. Further, although an electrical contact is used as the switch 6b, it may be equivalently configured to switch the insertion (or the direct grounding) of the resistor 6c as shown in FIG. 1, for example, the movement of the tip conductor 61. Is detected by the magnetic field,
The same control may be performed by a magnetic-electric conversion means such as a Hall element, or the movement of the tip conductor 61 may be optically detected and the same control may be performed by an optical-electric conversion means such as a photodiode. You may make it control.

In this embodiment, the thin film EL display tablet is used as the tablet 1, but the present invention is not limited to this. For example, FE
A display-integrated tablet using a D (field emission display) can also be adopted.

FIG. 9 shows the structure of the FED display integrated tablet. In this Figure, C ₁ -C _n are respectively connected to a cathode terminal Y electrodes y ₁ ~y _n. Further, G _{1 to} G _m are gate terminals, which are connected to the X electrodes x _{1 to} x _n , respectively. In each X electrode x _{1 to} x _n , a hole H for emitting an electron that is field-emitted from the cone-shaped emitter E is formed at a point intersecting with each Y electrode y _{1 to} y _n . It should be noted that this drawing is merely a schematic illustration, and in actuality, the holes H in which the emitters E are arranged are arranged in the order of several tens to several hundreds of thousands at a pitch of several μm by the integration technology. These are arranged on the substrate 21.

On the other hand, on the substrate 23 on the tablet surface side, the anode electrodes 24 connected to the anode terminals A are arranged in stripes, and each anode electrode 24 is provided with a phosphor 25. Then, by applying a voltage based on the cathode side Y electrodes y ₁ ~y _n display data in the vertical scanning and the gate-side X electrode x ₁ ~x _n, X to which a voltage is applied, the pixels in the intersection of the Y electrode, The electrons emitted from the emitter E are collected, the phosphor on the anode electrode 24 corresponding to the pixel is excited, and the display operation is performed.

Also in such an FED display integrated tablet, the coordinate input can be performed by the stylus pen by the capacitive coupling method as the coordinate input tablet as shown in FIG. 1, and like the above-mentioned embodiment. By configuring the stylus pen 6 and the peak detector 10, it is possible to prevent erroneous coordinate input detection.

[0050]

As described above, in the coordinate input device of the present invention, the detection end portion of the tip of the detection conductor means (stylus pen) is biased in the protruding direction at the first position and the first position. It is movable between the second positions retracted from the position, and the state in which the detection end is pressed by being brought into contact with the tablet means is the on state. The input impedance to the peak detecting means is lowered when it is in the off state apart from the tablet means. As a result, the detection input level of the erroneous coordinate detection signal generated by disturbance noise or the like can be lowered, and erroneous detection can be prevented.

Further, by eliminating such erroneous input coordinate detection, there is no problem even if the detecting conductor means is moved close to the tablet means, and the input operability is greatly improved. There is also the effect of

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of an embodiment of a coordinate input device of the present invention.

FIG. 2 is an explanatory diagram of a structure of a stylus pen according to an embodiment.

FIG. 3 is an explanatory diagram of a stylus pen according to an embodiment.

FIG. 4 is an explanatory diagram of display timing and scanning timing for input coordinate detection on the tablet of the embodiment.

FIG. 5 is an explanatory diagram of capacitance distribution.

FIG. 6 is an explanatory diagram of a coordinate input operation by the tablet, the stylus pen, and the peak detection unit of the embodiment.

FIG. 7 is an explanatory diagram of a coordinate input operation when the switch of the stylus pen of the embodiment is in an off state.

FIG. 8 is an explanatory diagram of an operation of preventing erroneous coordinate input when the switch of the stylus pen of the embodiment is on.

FIG. 9 is an explanatory diagram of an FED display integrated tablet that can be used as the tablet of the present invention.

[Explanation of symbols]

 1 Tablet 2 X Scan Driver 3 Y Scan Driver 4 Driver Controller 5 CPU 6 Stylus Pen 6a Detecting End 6b Switch 6c Resistor 7 Resistor 10 Peak Detecting Unit 11 Amplifier 12 First Comparison Circuit 13 Differentiation Circuit 14 Second Comparison Circuit 15 AND circuit 61 Tip conductor 62 Partition plate 63 Storage space 64 Spring 65, 66 contacts

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor So Nagasawa 629 Futaba, Mobara-shi, Chiba Futaba Electronics Co., Ltd.

Claims (2)

[Claims] 1. A tablet in which X electrodes driven by a scanning signal output from an X electrode driving means and Y electrodes driven by a scanning signal output from a Y electrode driving means are arranged in a matrix, and the tablet. A detection conductor means for outputting the scanning signal as a coordinate detection signal by electrostatic capacitance coupling when the detection end is brought into contact with the detection conductor, and a peak of the coordinate detection signal output from the detection conductor means. Based on the peak detection means for performing detection, the drive timing by the X electrode drive means and the Y electrode drive means, and the peak detection timing by the peak detection means, the coordinates at which the detection conductor means abuts on the tablet means are calculated. A coordinate input device comprising coordinate detection control means for detecting, wherein the detection conductor means has a detection end portion. , Is movable between a first position biased in the protruding direction and a second position retracted from the first position, and when the detection end is in the first position, A coordinate input device, characterized in that the input impedance of the coordinate detection signal from the detection conductor means to the peak detection means is lowered. 2. The peak detection means is configured to compare the coordinate detection signal output from the detection conductor means with a predetermined threshold value and detect the peak value based on the comparison output. The coordinate input device according to claim 1, wherein: