JP3342539B2 - Coordinate input device - Google Patents

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,
For more information, suitable for use in the field of pen input information equipment, etc.
For example, the present invention relates to a coordinate input device that superimposes a display position on a display screen of a liquid crystal display device or the like to associate a display position with an input position.

In recent years, for example, ATMs (Au
Many coordinate input devices such as a touch panel of a tomatic Teller's Machine), a pen input personal computer, and a pen input word processor have been developed.

In this system, a coordinate input device is arranged on a display screen of a CRT (Cathode Ray Tube), a liquid crystal display device, or the like, and position information is input by pressing the coordinate input device.

However, in such a coordinate input device, it is necessary to increase the number of electrodes for position detection in order to increase the position accuracy in the effective input area, and the number of lead wires increases.

[0005] In the case of coordinate detection by pressurization, it is necessary to perform position detection in a cycle as short as possible in order to increase input accuracy. If this cannot be reliably performed, an accurate contact position cannot be measured.

Therefore, it is necessary to suppress the number of lead wires and to perform position detection in a short cycle.

[0007]

2. Description of the Related Art Conventional coordinate input devices of this type include:
For example, Japanese Patent Application Laid-Open Nos.
An example is disclosed in JP-A-8-35679.

As shown in FIG. 13, a coordinate input device disclosed in Japanese Patent Laid-Open Publication No. Sho 56-11582 has a resistance film 1, a detection electrode film (not shown), a switch means 3, a drive power supply 4, and a signal output unit 5. The switch means 3 includes a plurality of diodes D connected to a point-like electrode formed on the periphery of the resistance film 1.
And the diode groups 6 to 9 composed of

On the other hand, a coordinate input device disclosed in Japanese Patent Application Laid-Open No. 58-35679 has a resistance film 1, a detection electrode film (not shown), a switch means 3 ', and a drive power supply 4 as shown in FIG.
The switch means 3 ′ is composed of switch groups 6 ′ to 9 ′ each including a plurality of analog switches S connected to a point-like electrode formed on the periphery of the resistance film 1.

That is, since the diode D can also be regarded as an analog switch S in operation, both of the above-described conventional examples read the change in the potential at the pressure point and specify the coordinates of the pressure point. This is for inputting coordinates.

[0011]

However, in such a conventional coordinate input device, a change in the potential at the pressure point is read and the coordinates of the pressure point are specified. As the number of point electrodes formed on one side of the resistive film increases, the linearity of the peripheral portion in the effective input area, that is, the equipotential line on which the electric field acts approaches a straight line, and the positional accuracy in the peripheral portion improves. When the number of electrodes increases, the number of lead wires increases accordingly (for example, when the number of dot electrodes on one side is nine, the number of lead wires is 36). There was a problem.

For example, when the input is a pen input, the probability that the palm contacts the input surface is high in an insulating film formed so as to make an electrical connection only at the time of pressurization. In order to distinguish between pressure and palm pressure, the spacer provided between the resistive film and the detection electrode film is small and arranged at short intervals. It will be turned off repeatedly. For this reason, there has been a problem that an accurate contact position cannot be detected unless the detection cycle of the contact between the resistance film and the detection electrode film is reliably performed in a short cycle.

Further, the fluctuation of the voltage applied to the resistive film is closely related to the detection accuracy of the input position. In the conventional coordinate input device, the voltage drop occurs in the switch element for selectively applying the voltage. Therefore, there is a problem that high-precision position detection is difficult.

An object of the present invention is to provide a coordinate input device for detecting a position with high accuracy while suppressing the number of lead wires.

[0015]

In order to achieve the above object, a coordinate input device according to the present invention uses, as coordinate information, a pressing position of a pressing body for selectively pressing an input unit having a predetermined input area surface. In the coordinate input device for detecting, the input unit includes a first substrate formed with a plurality of point-like electrodes corresponding to four sides on a rectangular resistive film, and points on two opposite sides of the first substrate. A voltage applying means for applying a voltage in a time-division manner in two orthogonal axes directions to the shape electrode, and a conductive film having a common electrode at a predetermined interval from the first substrate; A voltage application unit for applying a voltage is provided, and a second substrate for detecting a substrate potential of the first substrate is provided.

In this case, it is preferable to provide an opening / closing means for applying a voltage to the point-shaped electrode of the first substrate and the common electrode of the second substrate. It is effective to measure the voltage of the point electrode of the first substrate and correct the voltage drop of the switching means.

Further, when detecting the pressing position of the pressing body, the contact between the first substrate and the second substrate is detected at predetermined time intervals, and when the contact is detected continuously, the first substrate is detected. It is also effective to apply a voltage to the substrate in a time sharing manner.

[0018]

According to the present invention, the number of lead wires can be significantly reduced by providing the second substrate with the opening / closing means for applying a voltage.

Even if a voltage drop occurs in the resistance film of the first substrate, the same voltage is detected from the detection electrode at any position on the input area surface by applying the correction voltage to the point-like electrode, Highly accurate position detection is performed.

Further, the detection operation is performed when the contact between the first substrate and the second substrate is continuously detected at predetermined time intervals, thereby preventing erroneous detection.

That is, the coordinate position can be detected with high precision while the number of lead wires is suppressed.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a first embodiment of a coordinate input device according to the present invention, and FIG. 1 is a block diagram showing a main part configuration of the first embodiment.

In FIG. 1, the same reference numerals as those in the conventional example shown in FIG. 13 indicate the same parts.

The coordinate input device of this embodiment is roughly divided into a resistance film 1 as a first substrate, a detection electrode film 2 as a second substrate,
It comprises a switch means 3, a drive power supply 4 as a voltage application section, a signal detection section (not shown), and a switch section 16 as an opening / closing means. The switch means 3 is formed in the periphery of the resistive film 1. A plurality of diodes D connected to a point electrode
And four diode groups.

Further, as shown in FIG. 2, the switch means 3 comprises four switch groups consisting of a plurality of analog switches S connected to a point-like electrode formed on the periphery of the resistive film 1. May be.

In FIGS. 1 and 2, reference numeral 20 denotes a switch element, 21 denotes a resistance element, 22 denotes an A / D converter, and 23 denotes an MPU.

FIG. 3 is a cross-sectional view showing the main configuration of the coordinate input device of this embodiment.

In FIG. 3, 100 is a glass substrate, 101 is an ITO film corresponding to the resistance film 1, 102 is a spacer, 103
Is an ITO film corresponding to the detection electrode film 2, 104 is a PET sheet, 105 is an adhesive, 106 is an ITO bonding electrode, 10
7 is a gate control electrode, 108 is a ground electrode, 109 is F
ET and 121 are connection electrodes, and 122 is a conductive adhesive.

Next, the procedure for forming the input section will be described.

First, as a first substrate, an ITO film 101 is formed on a glass substrate 100 by a known method, and an insulating film and a spacer 102 are formed by a screen printing method or a photosensitive resin material by photolithography. Alternatively, by dispersing the minute spacers 102, the two ITO films 101 and 103, that is, the resistance film 1 and the detection electrode film 2 are brought into contact only when pressure is applied.

Then, the ITO bonding electrode 106 is formed by printing a conductive paint such as an Ag paste.
The number of bonding electrodes per side on 00 is obtained from the required effective area of the coordinate input device. Incidentally, the ratio of the effective input area to the area of the entire coordinate input device increases as the number of electrodes increases.

FIG. 4 shows the relationship between the input electrode and the distortion of the electric field for each number of electrodes on one side of the glass substrate 100.

As shown in FIG. 4, when the number N of electrodes on one side is 9, the area where the electric field distortion is 0.2% is about 90% of the effective input area per axis.

Next, the second substrate is made of, for example, P which is a protective film.
The ITO 103 is formed by vapor deposition on the ET sheet 104 by a known method, and the extraction electrode is formed by printing an Ag pace or the like.

The two substrates are bonded together with an adhesive 105 or the like so that the ITO deposition surfaces face each other, and a gate control electrode 107 and a connection electrode 12 are placed on a PET sheet 104.
1. The ground electrode 108 is formed by printing a conductive paint such as an Ag paste. The connection between the connection electrode 121 and the ITO bonding electrode 106 by a conductive adhesive
The lands to which the drain terminal and the source terminal of 09 are bonded are formed on the connection electrode 121 and the ground electrode 108 by printing or the like, and after the FET 109 is mounted, heat treatment is performed to fix it.

In this embodiment, since the FET 109 is provided above the periphery of the PET sheet 104, the effective input area can be increased with respect to the entire area of the coordinate input device as compared with the related art. This is because the FET 109
This is because it is provided in the vicinity of the point-like electrode where the linearity of the equipotential line on which the electric field acts is originally poor, that is, above the peripheral portion of the PET sheet 104. That is, the FET 109 is the PET sheet 104 that constitutes the touch panel of the coordinate input device.
Above the peripheral portion excluding the effective input area of
Further, since the FET 109 is provided on the second substrate, the number of electric wires to be drawn out from the ITO junction electrode 106 functioning as a point-like electrode can be effectively reduced. Further, the FET 109 has an ITO junction electrode (point-like electrode) 106.
Since it is located further inside the touch panel, the size of the entire coordinate input device can be made smaller than that of a conventional coordinate input device having an effective input area of the same size.

FIG. 5 is a sectional view showing the structure of a main part of a second embodiment of the coordinate input device according to the present invention. 5, the same reference numerals as those in the first embodiment shown in FIG. 3 denote the same parts.

In this embodiment, the FET 10 of the first embodiment is used.
9 uses a diode 120 instead of the gate control electrode. In this embodiment, the same effects as in the first embodiment can be obtained.

FIG. 6 is a sectional view showing a main part of a coordinate input device according to a third embodiment of the present invention. 6, the same reference numerals as those in the first embodiment shown in FIG. 3 denote the same parts.

In this embodiment, instead of forming the connection electrode 122, the drain terminal and the source terminal of the FET 109 are connected to the ground electrode 108 and the ITO junction electrode 106. In this embodiment, substantially the same effects as those of the first embodiment can be obtained.

FIG. 7 is a sectional view showing a main part of a fourth embodiment of the coordinate input device according to the present invention. 7, the same reference numerals as those in the third embodiment shown in FIG. 6 indicate the same parts.

In this embodiment, a diode 120 is used instead of the FET 109, and the gate control electrode is removed. In this embodiment, substantially the same effects as those of the first embodiment can be obtained.

FIG. 8 is a sectional view showing a main part of a fifth embodiment of the coordinate input device according to the present invention. 8, the same symbols as those in the first embodiment shown in FIG. 3 indicate the same parts.

In this embodiment, the insulating film 132 is provided on the ITO film 101 in the peripheral portion of the touch panel. The ground electrode 108 and the detection electrode 131 are provided on the insulating film 132.

The first substrate and the second substrate are connected to the detection electrode 131.
Are adhered by the conductive adhesive 130 via the. Therefore, it is not necessary to print the connection electrode and the ground electrode on the second substrate, and the manufacturing process of the coordinate input device can be simplified.

In this embodiment, the diode 1
Since the reference numeral 20 is located on the inner side of the touch panel with respect to the ITO bonding electrode (point-like electrode) 106, the same effect as in the first embodiment can be obtained.

FIG. 9 is a sectional view showing the configuration of the main part of a sixth embodiment of the coordinate input device according to the present invention. 9, the same reference numerals as those in the first embodiment shown in FIG. 3 indicate the same parts.

In this embodiment, a flexible printed wiring board (or circuit) 142 is used. One end of the flexible printed wiring board 142 is electrically connected to the ITO bonding electrode (point-like electrode) 106 via a conductive adhesive 141. The other end of the flexible printed wiring board 142 is connected to the PET sheet 104. The gate control electrode 107, the ground electrode 108, and the connection electrode 121
Each is provided on the flexible printed wiring board 142 above the PET sheet 104.

In the present embodiment, substantially the same effects as those of the first embodiment can be obtained, and by providing the flexible printed wiring board 142, required electrical connection can be easily performed. Also, it is possible to reliably obtain the necessary electrical connection without reducing the effective input area of the touch panel.

FIG. 10 shows a seventh embodiment of the coordinate input device according to the present invention.
It is sectional drawing which shows the principal part structure of an Example. In FIG. 10, FIG.
The same reference numerals as those in the fifth embodiment denote the same parts.

In this embodiment, a flexible printed wiring board (or circuit) 145 is provided instead of the insulating film 132 shown in FIG.

In this embodiment, substantially the same effects as those of the first embodiment can be obtained, and necessary electric connection can be easily performed by providing the flexible printed wiring board 145. Further, necessary electrical connection can be reliably obtained without reducing the effective input area of the touch panel.

Next, an example of coordinate detection will be described with reference to FIG.

First, after the power is turned on, the MPU 23 turns on the switch element 20 and the switch S1, and enters the sleep mode. At this time, the total current consumption is at a level of several μA.

Here, the resistive film 1 is pressed by the input pen.
When the detection electrode film 2 comes in contact with the detection electrode film 2, "L" is input to the interrupt input terminal of the MPU 23, the MPU 23 returns from the sleep mode to the normal mode, and after waiting for a certain time, the level of the interrupt input terminal is confirmed. When "L" is detected again, the operation shifts to the coordinate measurement operation. When the second detection is "H", it is determined that the two electrodes have been separated, and the MPU 23 returns to the sleep mode. enter.

In the coordinate measurement, the switch element 20 is turned off, the current flowing from the resistance element 21 is set to 0, and the potential at the contact point can be accurately measured.

Then, the switches S2 and S3 are turned on to cause a potential drop in the drive-side electrode film. MPU23
Operates the A / D converter 22 a predetermined number of times (for example, 32
Times) and the variation between all measured values is constant (300m)
V) After confirming that:
Raw data of coordinates.

Next, the switch element 20 and the switch S1 are turned on, and it is confirmed that the potential of the interrupt input terminal of the CPU 23 is "L". When "L" is detected, the switches S1 and S4 are turned on. A potential drop is generated in the driving-side electrode film. The CPU 23 drives the A / D converter 22 a predetermined number of times (for example, 32 times) and confirms that the variation between all the measured values is equal to or less than a fixed value (300 mV). Raw data.

Next, the switch element 20 and the switch S1 are turned on, and it is confirmed that the potential of the interrupt input terminal of the CPU 23 is "L". When "L" is detected, the measurement of the coordinates is terminated. The raw data of the Y coordinate is processed by the previously input coordinate correction data, and the data is transmitted to the host device.

When the data transmission is completed, the switch S1
And the switch element 20 are turned on, and the above-described processing is repeatedly performed.

When the variation between all the measured values in both the X-axis measurement and the Y-axis measurement exceeds a certain value, the processing shifts to the off-delay processing.

In the off-delay processing, after waiting for a predetermined time, M
Check the level of the interrupt input terminal of PU23,
Is detected, the process proceeds to the X-axis measurement process. If "H" is detected, the switch S1 and the switch element 20 are turned on to enter the sleep mode and enter the standby state.

FIG. 11 shows a correction example for correcting a voltage drop caused by the switch element.

In this embodiment, in order to correct a voltage drop due to the switch element for driving the resistive film, a lead wire is drawn out from the junction electrode with the resistive film 1 so that the diode D is driven so that a current flows. The switch unit 3 is connected to the input of the A / D converter 22 to measure the potential of the resistive film 1 at the voltage application point.

For example, in FIG.
_XDH , V _{XDL Further} , _assuming that the voltage at the contact position is VX and the distance between the point electrodes is L, the contact position X can be obtained by the following equation.

[0067]

(Equation 1)

FIG. 12 shows another correction example for correcting a voltage drop caused by the switch element.

In this embodiment, the value of the current limiting resistor 45 is selected so that the same type of current as the switching element 20 is turned on flows into the same type as the switching element driven by the resistive film. Then, the on / off voltage Vfd of the diode 46 is changed by switching the switch means 3 to A / D
This is measured by the converter 22.

For example, in FIG. 12, when the power supply voltage is V _CC , the voltage at the contact position is Vx, and the distance between the point-like electrodes is L, the contact position X is obtained by the following equation.

[0071]

(Equation 2)

As described above, in this embodiment, the number of lead lines from the input section is significantly reduced, and the device can be reduced in size and weight.

Further, in this embodiment, it is possible to accurately detect the pressing position.

Further, in the coordinate detection in this embodiment,
Even if the voltage value fluctuates due to the voltage drop of the driving element, the measured value of the coordinates is not affected, so that high detection accuracy can be obtained.

[0075]

According to the present invention, the number of lead wires can be remarkably reduced by providing the second substrate with the switching means for applying voltage, and even if a voltage drop occurs in the switching means for applying voltage. By measuring and correcting the voltage of the dot electrode, highly accurate position detection can be performed at any position on the input area surface.

Further, by performing the detection operation when the contact between the first substrate and the second substrate is continuously detected at predetermined time intervals, erroneous detection can be prevented.

Therefore, highly accurate coordinate position detection can be realized while suppressing the number of lead wires.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a first embodiment.

FIG. 2 is a block diagram showing another configuration example of the first embodiment.

FIG. 3 is a cross-sectional view showing a configuration of a main part of the first embodiment.

FIG. 4 is a diagram showing a relationship between the number of electrodes on one side, an input area, and an electric field distortion.

FIG. 5 is a sectional view showing a configuration of a main part of a second embodiment.

FIG. 6 is a sectional view showing a configuration of a main part of a third embodiment.

FIG. 7 is a sectional view showing a configuration of a main part of a fourth embodiment.

FIG. 8 is a sectional view showing a configuration of a main part of a fifth embodiment.

FIG. 9 is a sectional view showing a configuration of a main part of a sixth embodiment.

FIG. 10 is a sectional view showing a configuration of a main part of a seventh embodiment.

FIG. 11 is a diagram illustrating a correction example for correcting a voltage drop caused by a switch element.

FIG. 12 is a diagram showing another correction example for correcting a voltage drop caused by a switch element.

FIG. 13 is a diagram showing a configuration of a main part of a conventional example.

FIG. 14 is a diagram showing a main configuration of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resistance film (1st substrate) 2 Detection electrode film (2nd substrate) 3 Switching means 4 Drive power supply (voltage application part) 5 Signal detection part 6-9 Diode group 10 Switch part 20 Switch element 21 Resistance element 22 A / D Converter 23 MPU 100 Glass substrate 101 ITO film 102 Spacer 103 ITO film 104 PET sheet 105 Adhesive 106 ITO bonding electrode 107 Gate control electrode 108 Ground electrode 109 FET 121 Connection electrode 122, 130, 141 Conductive adhesive 131 Detection electrode 132 Insulation Membrane 142,145 Flexible printed wiring board

Continuation of the front page (72) Inventor Katsuya Irie 1015 Uedanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Within Fujitsu Limited (56) References JP-A-61-208533 (JP, A) JP-A-64-50116 (JP, A) Japanese Utility Model Showa 63-39748 (JP, U) Japanese Utility Model Showa 63-92945 (JP, U) Japanese Utility Model Showa 5-289805 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) ) G06F 3/03-3/033

Claims (3)

(57) [Claims] (1)Detects the coordinates of any pressurized position
A coordinate input device, Board and A resistive film provided on the substrate, A spacer made of an insulating material; A detection electrode film opposed to the resistance film via the spacer, A peripheral portion on the resistive film is provided along each side of the resistive film.
A plurality of point-shaped electrodes, A voltage is applied to the point electrode provided on the substrate.
Switches electrically connected to the point electrode for
Element and A protective film provided on the detection electrode film, Provided at a position on the protective film corresponding to a peripheral portion of the resistive film
With a wiring film, When the central portion of the resistive film is on the inside, the point-like electrode
It is arranged almost outside the switch element, The switch element is electrically connected to the wiring film to maintain the protection.
Characterized by being provided above the protective film, Coordinate input device. 2. The method according to claim 2, wherein the wiring film and the point electrode are electrically connected to each other.
Further equipped with a flexible printed wiring board for connection
Wherein the coordinate input apparatus according to claim 1. (3)The switch element applies an electric current to the point electrode.
When the pressure is applied, the equipotential lines acting on the electric field are distorted.
Arrange in the region above the protective film corresponding to the region on the resistive film.
Characterized by being placed The coordinate input device according to claim 1.