JP3214951B2 - Coordinate input device and coordinate input method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a small rather small power consumption
Yes, a coordinate input device that can be incorporated into a liquid crystal display
About the location.

[0002]

2. Description of the Related Art Conventionally, as this kind of coordinate input device, FIG.
4 is known. The device shown in FIG. 14 includes a plurality of primary electrode lines X1, X2,... Provided in parallel with each other for coordinate detection, and a plurality of primary electrode lines X1, X2,. Of the secondary electrode lines Y1, Y2, ...
, And these primary electrode lines X1, X2,.
, A plurality of connection lines Z11, Z connected between each other
, Z21, Z22,... And sensing elements S11, S12,.
, The power supply device 1 connected to the electrode lines, the switches M1, M2,... Installed on the power supply device 1 side of the primary electrode lines X1, X2,. Power supply 1
Are mainly configured by switches N1, N2,... The sensing elements S are light, heat,
The resistance value is changed by an external factor such as an electromagnetic field or pressure. That is, each of the primary electrode lines X and 2
The next electrode lines Y are configured to be connected by a resistor having a value that can be detected.

Therefore, in order to input coordinates using the above-described apparatus, a pulse voltage or the like is applied from the power source 1 to each of the primary electrode lines X and the secondary electrode lines Y through switches N1, N2,. A current always flows through the sensing element S which can be regarded as a resistance, and by reading a change in the current value of the sensing element S caused by an external factor such as light, heat, an electromagnetic field or pressure, the resistance value of any sensing element S changes. Thus, it is possible to determine the change in light, heat, electromagnetic field, or pressure at a predetermined coordinate position.

[0004]

However, in the conventional coordinate input device having the structure shown in FIG. 14, a current must always flow through the sensing element S.
There is a drawback that power consumption is large. In addition, it has been considered to manufacture a device in which the coordinate input device having the above configuration and a liquid crystal display device are combined. The liquid crystal display device used in this case includes a scanning electrode line and a signal electrode line wired in a matrix, and a switching element and a pixel electrode provided in each part partitioned by the scanning electrode line and the signal electrode line. And applying an electric field to the liquid crystal provided on the pixel electrode to control the orientation of the liquid crystal.

In the case of constructing a device combining the liquid crystal display device and the coordinate input device, a scanning electrode line and a signal electrode line of the liquid crystal display device, a primary electrode line X and a secondary electrode line Y of the coordinate input device are provided. Are also used, the size and simplification of the device can be reduced. However, in the coordinate input device, it is necessary to always supply a current to the sensing element as described above. Therefore, if the primary electrode line X, the secondary electrode line Y, and the scanning electrode line or the signal electrode line are also used. Since the voltage for the sensing element is applied to the pixel electrode of the liquid crystal display device, and the electric field applied to the liquid crystal by the pixel electrode fluctuates and the display is adversely affected, the primary electrode lines X. There is a problem that the next electrode lines Y,... And the scanning electrode lines and the signal electrode lines must be formed as separate circuits. Then, there is a problem that the circuit configuration becomes complicated and the yield decreases.

[0006] The present invention has been made in view of the above circumstances, the power consumption is small, a small, can be easily be incorporated into a liquid crystal display device, easy coordinate input equipment integrated in that case The purpose is to provide.

[0007]

According to the first aspect of the present invention, a plurality of scanning electrode lines and a plurality of signal lines are provided.
And the scanning electrode is wired in a matrix.
The lines serve as scanning signal sources, and the signal electrode lines serve as display signal sources.
Connected to each of the scanning electrode lines and each of the signal electrode lines.
Therefore, the switching element and the pixel electrode
And a liquid crystal driven by each of the pixel electrodes is provided.
And the switching element is connected to the scanning electrode.
Switching operation is performed by the scanning signal supplied to the pole wire.
The display signal supplied to the signal electrode line is
The liquid crystal is supplied to the electrodes to drive the liquid crystal, and the scanning electrode lines and the
The scanning electrode line near each intersection with the signal electrode line and
By light, heat, electromagnetic field or pressure between signal electrode wires
Sensing element with variable resistance and capacitor in series
Connected between the scanning electrode line and the signal electrode line.
AC detection signal for coordinate detection that does not affect crystal display
And the resistance or impedance of each sensing element
Is detected .

According to a second aspect of the present invention, a plurality of scanning electrode lines and a plurality of signal electrode lines are connected to each other.
And the scanning electrode lines are connected to a scanning signal source.
The signal electrode lines are connected to display signal sources, respectively,
Each scanning electrode line and each signal electrode line are separated.
Switching element, pixel electrode and capacitor section
And a liquid crystal driven by each of the pixel electrodes is provided.
And the switching element is connected to the scanning electrode line.
The switching operation is performed by the supplied scanning signal,
The display signal supplied to the signal electrode line is transmitted to the pixel electrode and
The liquid crystal is supplied to the storage section to drive the liquid crystal, and is supplied to the storage section.
The resistance changes due to light, heat, electromagnetic field or pressure.
Sensing elements are connected in series, and the scanning electrode lines and the signal
Coordinate detection that does not affect the liquid crystal display between the electrode line
AC detection signal flows, and the resistance of each sensing element
Or detecting an impedance .

According to a third aspect of the present invention, a plurality of scanning electrode lines and a plurality of signal electrode lines are connected to each other.
And the scanning electrode lines are connected to a scanning signal source.
The signal electrode lines are connected to display signal sources, respectively,
Each scanning electrode line and each signal electrode line are separated.
The switching element and the pixel electrode are provided in the
A liquid crystal driven by each pixel electrode is provided.
The switching element is supplied to the scan electrode line.
The switching operation is performed by the scanning signal, and the signal
A display signal supplied to the polar line is supplied to the pixel electrode.
Driving the liquid crystal, the output terminal of the switching element and the front
Light, heat, electromagnetic field or pressure between the
The sensing element whose resistance value changes
Influences the liquid crystal display between the scanning electrode line and the signal electrode line
The AC detection signal for coordinate detection that does not affect the
To detect the resistance or impedance of the sensing element.
This is a feature of the present invention.

According to a fourth aspect of the present invention, in order to solve the above-mentioned problem, the AC detection signal has an AC detection signal of 60 Hz or more.
It is characterized by being a number . AC detection signal is 60Hz or less
If it is above, you can feel flicker with the naked eye in the case of liquid crystal display
I do not.

According to a fifth aspect of the present invention, in order to solve the above-mentioned problem, the AC detection signal is set to 10 kHz to 1 MHz.
Characterized in that the signal is an AC detection signal. The liquid crystal itself responds during the liquid crystal display, so if there is no effect on the liquid crystal display
In both cases, considering the ease of circuit design, etc.
The detection signal is an AC detection signal of 10 kHz to 1 MHz.
Preferably, there is.

According to a sixth aspect of the present invention, in order to solve the above-mentioned problem, the sensing element according to the second aspect is characterized in that the intensity of light is low.
Using a phototransistor that changes the resistance value
Characterized in that: Sensing element is photo
If it is a transistor, it is incident on the sensing element
When an object blocks the light, the resistance of the sensing element changes.
Therefore, the input position can be detected. Claim 7
In order to solve the above-mentioned problems, the invention described in the publication describes a coordinate detection signal.
A signal source is connected to the signal electrode line.
You.

[0013]

According to the first aspect of the present invention, a plurality of scanning electrodes are provided.
The wires and the plurality of signal electrode wires are wired in a matrix,
The scanning electrode line is a scanning signal source, and the signal electrode line is a display.
Each of the scanning electrode lines and each of the signals.
Switching element in the area separated by the
And a pixel electrode, and are driven by each of the pixel electrodes.
Liquid crystal is provided and a sensor is located near each intersection.
A scanning element and a capacitor are connected in series, and the scanning electrode
Do not affect the liquid crystal display between the signal line and the signal electrode line.
The AC detection signal for detecting the
Reading the resistance or impedance change of the
Which area of the area wired in a matrix
Light, heat, electromagnetic field, or pressure applied to the sensing element
Is the resistance change or impedance of the sensing element
It is easily detected from changes. Also, the scanning electrode line and the signal
For detecting coordinates without affecting the liquid crystal display between the electrode lines
AC detection signal flows, and the resistance of each sensing element changes.
Or by detecting the impedance change,
Coordinate detection can be performed without affecting the liquid crystal display.

According to the second aspect of the present invention, a plurality of running
Inspection electrode lines and multiple signal electrode lines are wired in a matrix
Wherein the scanning electrode line is a scanning signal source and the signal electrode line is
Are respectively connected to the display signal sources, and each of the scanning electrode lines is
A switch is applied to the part separated by each signal electrode line.
A pixel element, a pixel electrode, and a capacitor section.
A liquid crystal driven by the poles is provided, and a capacitance section is provided.
A sensing element is connected in series to the scanning electrode line and
Coordinate detection that does not affect the liquid crystal display between the signal electrode lines
Since the output AC detection signal flows, the sensing element
By reading the resistance change or impedance change
Of the area wired in a matrix
Light, heat, electromagnetic field, or pressure applied to the
Changes in the resistance or impedance of the sensing element.
Easily detected from Also, the scanning electrode line and the signal
For detecting coordinates without affecting the liquid crystal display between the electrode lines
AC detection signal flows, and the resistance of each sensing element changes.
Or by detecting the impedance change,
Coordinate detection can be performed without affecting the liquid crystal display. Change
If a sensing element is connected in series with the capacitor,
Use the storage capacitance of the part as a capacitor for the sensing element.
In this case, the signal for the liquid crystal display
The signal for coordinate detection can be superimposed.
Shift to select scan electrode line and signal electrode line when
A selection circuit for LCD display such as a register is selected for inputting coordinates.
This can be used also as a selection circuit.

According to the third aspect of the present invention, a plurality of running
Inspection electrode lines and multiple signal electrode lines are wired in a matrix
Wherein the scanning electrode line is a scanning signal source and the signal electrode line is
Are respectively connected to the display signal sources, and each of the scanning electrode lines is
A switch is applied to the part separated by each signal electrode line.
A pixel element and a pixel electrode.
A liquid crystal to be driven is provided, and the switch
Sensing element between the output terminal of the sensing element and the pixel electrode
Are connected in series, and the scan electrode line and the signal electrode line
AC detection for coordinate detection without affecting the LCD display in between
Since the signal is passed, the resistance change or
By reading the impedance change, the matrix
Light to the sensing element at any position in the
Sensing whether heat, electromagnetic field, or pressure has acted
Easy detection from element resistance change or impedance change
Is done. A liquid crystal is provided between the scanning electrode line and the signal electrode line.
An AC detection signal for coordinate detection that does not affect the display
Resistance change or impedance of each sensing element
Detecting changes can affect the LCD display.
Coordinates can be detected without blurring. In this configuration,
As in the case of the invention of the above, the storage capacity of the capacitance section is sensed.
It can be used as a capacitor for the element,
In this case, the coordinate detection signal should be superimposed on the liquid crystal display signal.
In this case, scanning electrode lines and signal
For liquid crystal display such as shift register to select polar line
Function as a selection circuit for coordinate input
Becomes possible.

On the other hand, a plurality of scanning electrode lines and a plurality of signal electrode lines are wired in a matrix, each electrode line is connected to a power source, and a thin film transistor or a thin film transistor is provided at a portion separated by the scanning electrode lines and the signal electrode lines. A switching element such as an MIM element and a pixel electrode are provided, and a part separated by the scanning electrode line and the signal electrode line is provided with a sensing element and a charge storage unit. The liquid crystal is driven by the voltage applied to the pixel electrode by the operation, and display is performed. In addition, if an AC signal is applied to the sensing element and the charge storage section provided for each part separated by the scanning electrode lines and the signal electrode lines provided in a matrix and if the impedance change of the sensing element is read, light, heat, Since it is possible to detect a coordinate position where an electromagnetic field or pressure is applied, it is possible to input coordinates at an extremely fine position using the precision of forming the scanning electrode lines and the signal electrode lines of the liquid crystal display device as it is. In addition, by detecting at a high frequency that does not affect the liquid crystal display and inputting the coordinates, the coordinates can be input at any time independently of the liquid crystal display without affecting the liquid crystal display.

Further, by providing a sensing element in series with the storage capacitor of the liquid crystal display device, similar to the above-described example,
An AC signal is applied to a sensing element and a storage capacitor provided for each part separated by a scanning electrode line and a signal electrode line provided in a matrix, and a change in the impedance of the sensing element is read. Alternatively, since the coordinate position to which the pressure is applied can be detected, it is possible to input the coordinates at an extremely fine position using the precision of forming the scanning electrode lines and the signal electrode lines of the liquid crystal display device as it is.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A shows a coordinate input device of a first basic configuration example . This device includes a plurality of primary electrode lines X1, X2,... Provided in parallel with each other for coordinate detection. A plurality of secondary electrode lines Y1, Y2,... Provided in a direction perpendicular to the primary electrode lines X1, X2,. And
These primary electrode lines X1, X2,... And secondary electrode lines Y1, Y
2,..., Z21, Z2
Are connected, and connection lines Z11, Z12, ..., Z21, Z2
2, ... are sensing elements S11, S12, ..., S21, S2.
2, ... are connected, and connection lines Z11, Z12, ..., Z21, Z2
, Incorporate capacitors C11, C12,..., C21, C22,... In series with the sensing element S. The primary electrode lines X are connected through a common electrode line 3, A power supply device 5 is connected to the secondary electrode lines Y via a common electrode line 4. Also, the primary electrode lines X1, X2,.
Are provided with switches M1, M2,...
A switch N is provided on the power supply 5 side of the secondary electrode lines Y1, Y2,.
1, N2,... Are provided.

The sensing element S is one whose resistance value, impedance, reactance, etc. change due to external factors such as light, heat, electromagnetic field or pressure. That is,
Specifically, a phototransistor or resistance element whose resistance value changes with the intensity of light, a thermistor whose resistance value changes with temperature, a piezoresistive element whose resistance value changes with pressure, a Hall element whose resistance changes with an electromagnetic field, etc. Become.
Further, as the sensing element S, a circuit shown in FIG. 1B in which a transistor and these elements are combined to emphasize the resistance change amount and make it easier to detect can be adopted. In the circuit shown in FIG.
2 transistor, 21 denotes a constant resistance element, 22 Sensing
The variable resistance element as a switching element is shown.

With the above structure, each switch N1, N2,
, M 1, M 2,... Are selectively opened and closed, and a DC current flows from the power supply 5 to each of the electrode lines X, Y,. Thereafter, the current stops flowing, and the resistance of each sensing element S cannot be read. That is, each of the electrode wires X ... and Y ... is insulated from the direct current. On the other hand, when an alternating current is passed from the power supply 5 to each of the electrode lines X,..., Y, it is possible to read the impedance change of each sensing element S.

Here, a description will be given below of a comparison of the current fluctuation state when a pulsed DC voltage is applied to the sensing elements S with and without the capacitor. Assuming a structure in which the sensing element S and the capacitor C are incorporated in the connection line Z connected to the power supply 5 as shown in FIG. 2, a pulsed DC voltage as shown in FIG. The current at this time is as shown in FIG. As is apparent from FIG. 4, when the capacitor C is present, the current flows as much as necessary to charge the capacitor C and then stops flowing. As shown by the chain line 4, a constant current flows for a predetermined time.
Therefore, when the capacitor C is provided, the power consumption is smaller than when the capacitor C is not provided.

Next, the sensing element S of the device shown in FIG.
As a specific example of the sensing elements S′11, S′12,..., S′21, S′22, and the like whose resistance values change due to light, heat, an electromagnetic field or pressure as shown in FIG. In this case, a method of detecting the coordinate position will be described. Here, for example, assuming that a pulsed DC voltage is applied to the circuit as shown in FIG. 6, the current waveform has a magnitude of the resistance value of the sensing element, that is, a magnitude of the time constant of the combination of the resistance and the capacitor of the sensing element. Changes as shown in FIG. Comparison of time constants, ie, sensing element S
... Comparison of the resistance value of the time length until decays to a value I ₁ with a charging current, or, from the start of the current application,
It made possible by comparing certain magnitude of current value after a predetermined time t _1. Also, when discharging the accumulated charges as described above, the time constants can be naturally compared in the same manner.

For example, looking at the current value I ₁ in FIG. 7, a sensor element having a small resistance of the sensing element S ′ has a low resistance I _{1 in} a short time.
When the resistance of the sensing element S ′ is large, it becomes I _{1 in} a later time. Therefore, when the current value becomes I _{1 in a} short time after the current starts flowing, the resistance of the sensing element S ′ is small, and when the current value becomes I ₁ in a long time, the resistance of the sensing element S ′ is large. Can be determined. This relationship can be similarly determined in the case of discharging from a capacitor. In addition, when viewed at time t ₁ in FIG. 7, those with a small resistance of the sensing element S ′ have a low current value, and those with a large resistance of the sensing element S ′ have a high current value. Therefore, the current value after a certain period of time t _{1 has} elapsed since the start of the current flow is detected, and the one with a large current value has a large resistance of the sensing element S ′, and the one with a small current value has a large resistance of the sensing element S ′. It can be determined that it is small. Also, when discharging the accumulated charge as described above, the determination can be made in the same manner as described above.

Therefore, the switches N1, N2,..., M1, M
2,... Are selectively opened and closed, and each electrode wire X
When a direct current is passed through..., Y, the magnitude of the current flowing through the capacitor C is detected during the time when the current flowing through the predetermined capacitor C reaches the predetermined current value or during the predetermined time from the relationship shown in FIG. This makes it possible to detect how much the resistance of the predetermined sensing element S ′ has changed. That is, by this, the sensing element S ′ at which position
It is possible to grasp how much light, heat, electromagnetic field or pressure has acted on the object and input coordinates.

The example shown in FIG. 8 shows an embodiment on the assumption that an alternating current is used for detecting coordinates in the coordinate input device shown in FIG. In the device of this example, each sensing element S'11, S'12, ..., S'21,
By detecting a change in the impedance of S′22,..., The sensing elements S′11, S′12,.
It is possible to grasp how much light, heat, electromagnetic field or pressure has acted on S'21, S'22,... And input coordinates.

FIGS. 9 and 10 show an embodiment in which the coordinate input device of the present invention is applied to an active matrix liquid crystal display device. FIG. 9 shows an equivalent circuit of one structural example in which a coordinate input device is incorporated in one structural example of an active matrix liquid crystal display device. The liquid crystal display device used in this example has scanning electrode lines G1, G2,... And signal electrode lines L1, L2,.
A switching element 10 such as a thin film transistor or an MIM element and a liquid crystal element 11 provided in each section defined by the scanning electrode lines G and the signal electrode lines L and a capacitor (storage capacitor) forming a capacitor.
It comprises a use) 12, the scanning electrode lines G1, G2, ... is a scanning circuit (a scanning signal source) 13 for driving the liquid crystal, the signal electrode lines L1, L2, ... the signal supply circuit (display for driving the liquid crystal Signal
14 ) . In addition, the liquid crystal element 1
Reference numeral 1 denotes a pixel electrode and a liquid crystal to which an electric field is applied by the pixel electrode. By applying a predetermined electric field to the liquid crystal from the pixel electrode driven by the switching element 10, the orientation of the liquid crystal is controlled and the display is performed. Is performed.

The scanning electrode lines G1, G2,... And the signal electrode lines L1, L2 of the active matrix liquid crystal display device.
The connection lines 15 connected to the scanning electrode lines G and the signal electrode lines L are provided at the intersections of the switching elements 10 on the side opposite to the switching elements 10. , A capacitor C ′ and a sensing element S ′ are incorporated in series. In an actual liquid crystal driving device, a signal electrode line and a scanning electrode line are stacked on a predetermined substrate via an insulating layer, and various regions before and after the formation of the electrode lines are formed in regions defined by the signal electrode lines and the scanning electrode lines. A structure in which a switching element and a capacitor are formed through a film forming process is obtained. Therefore, in the actual structure of the liquid crystal display device, the connection line 15 shown in the equivalent circuit of FIG. 10 does not exist, and a capacitor C ′ is formed between the scan electrode line G and the signal electrode line L. In this case, the sensing element S ′ is interposed in series with an insulating layer interposed therebetween.

The active matrix liquid crystal display device having the above-described structure has a high frequency alternating current between the scanning electrode lines G1, G2,... And the signal electrode lines L1, L2,. Coordinates can be detected by passing a signal, and display can be performed by applying an AC drive signal to the liquid crystal element 11 from the scanning circuit and the signal supply circuit as in the conventional case. That is, the gates of the horizontal switching elements 10 are opened from the scanning circuit 13 along the scanning electrode lines G1, G2,.
A signal corresponding to display or non-display in a pixel unit is applied to the liquid crystal element 11 provided in the vertical direction from the above to display characters or graphics corresponding thereto. The capacitance section 12
Since the voltage applied thereto can be held, each pixel can be provided with a kind of memory function, and even when the number of scans is reduced, the screen does not flicker and the power consumption can be reduced.

The AC signal used for coordinate detection has a voltage amplitude that does not affect the driving of the liquid crystal and has such a high frequency that the liquid crystal cannot respond. It is necessary to use a high frequency that does not matter. Specifically, it is necessary to set the frequency to 60 Hz or higher in order to prevent flickering with the naked eye.
In order that the liquid crystal itself does not respond, the frequency is preferably 10 kHz or more. However, in practice, several kH
z or more and several M considering the ease of circuit design.
It is preferable to use an AC signal having a frequency of less than or equal to Hz.

By using the above method, the coordinates can be detected completely independently of the display by the liquid crystal. That is, as described above, if an AC signal of 10 kHz to several MHz is passed and the resistance and impedance of each sensing element are measured, the coordinates can be detected. In addition, at present, the area surrounded by the scanning electrode lines G and the signal electrode lines L of the liquid crystal display device can be easily reduced to an extremely narrow area of the order of several tens of microns. Changes, pressure changes, heat changes or changes in the electromagnetic field can be measured. Therefore, a coordinate input device using the liquid crystal display device according to the present invention can detect a change in light or pressure, an electromagnetic field, or heat with extremely fine positional accuracy.

FIG. 11 shows an equivalent circuit of another embodiment in which a coordinate input device is incorporated in a liquid crystal display device. In a liquid crystal display device having a circuit configuration substantially the same as that of the liquid crystal display device shown in FIG. , The capacitor C ′ and the sensing element S ′ are omitted, and the sensing element S00 is incorporated in series in the connection line 16 in which the capacitance section (for storage capacitance) 12 is incorporated. In an actual liquid crystal driving device, a signal electrode line and a scanning electrode line are stacked on a predetermined substrate via an insulating layer, and various regions before and after the formation of the electrode lines are formed in regions defined by the signal electrode lines and the scanning electrode lines. Switching elements and capacitors after the film formation process
(For storage capacitor) . Therefore, in the actual structure of the liquid crystal display device, the connection line 16 shown in the equivalent circuit of FIG.
The switching element 10 is provided on the zero drain electrode 10a via an insulating layer constituting the capacitance section 12. The signal electrode line L is connected to a detector 17, a signal source 18 for coordinate detection, and a signal source 19 for display. These detector 17, signal source 18 for coordinate detection, and signal source 19 for display
Is built in the signal supply circuit 14 connected to the signal electrode line L as shown in FIG.
4 and a power supply for driving the supply circuit.

In this embodiment, the coordinate input device is constituted by combining the capacitance section 12 with a capacitor and a sensing element S00 using a phototransistor whose resistance value changes depending on the intensity of light. The capacitance section 12 accumulates a capacity called a storage capacity which is incorporated in a normal liquid crystal display device for improving display quality.
And is attached to each of the pixel electrodes. The capacity (C
_S ) is generally larger than the capacitance (C _LC ) of the liquid crystal, and therefore, as shown in FIG.
Since the signal for coordinate detection can be superimposed on the signal for liquid crystal display by using as a capacitor for the liquid crystal display, a selection circuit for liquid crystal display such as a shift register for selecting the scanning electrode line G and the signal electrode line L is coordinated. It can also be used as an input selection circuit.

That is, the capacitive part 12 and the sensing element S00 which are also used for detecting coordinates and are present on the same plane as the circuit of the liquid crystal display device are provided with horizontal switching elements G by the horizontal scanning electrode lines G in the display. The gate of 10 is open, and a detection signal is given by the signal supply circuit 14 via the signal electrode lines L. In this state, if the light illuminating the sensing element S00 is blocked by a finger or other object, the resistance of the sensing element S00 changes, and the state is transmitted to the detection circuit via the signal electrode lines L. Then, the input position can be detected by this detection circuit. 6 and 7 in the configuration shown in FIG.
It is also possible to input the coordinate position from the charging curve of the display signal for the capacitor described based on FIG.

FIG. 12 shows another embodiment in which a coordinate input device is incorporated in a liquid crystal display device. In a liquid crystal display device having the same circuit configuration as the liquid crystal display device shown in FIG. 9, a connection line 15 and a capacitor C 'are provided. And the sensing element S 'are omitted,
Connection part 23 between the capacitance part 12 for storage capacitance and the drain electrode 10 a of the liquid crystal element 11 and the switching element 10
And a sensing element S01 incorporated in series. That is, one end of the capacitance section 12 and one end of the liquid crystal element 11 are connected in parallel to the drain electrode 10 a as an output section of the switching element 10, the other end of the capacitance section 12 is grounded, The other end is grounded, and the sensing element S01 is connected to the switching element 10
Are connected in series between a drain electrode 10a as an output part of the first embodiment and a connection part of the capacitance part 12 and the liquid crystal element 11. Further, since the liquid crystal element 11 has the pixel electrode and the liquid crystal as described above, specifically, the sensing element S01 is connected in series between the drain electrode 10a as the output of the switching element 10 and the pixel electrode of the liquid crystal element 11. The structure is connected to. In an actual liquid crystal driving device, a signal electrode line and a scanning electrode line are stacked on a predetermined substrate via an insulating layer, and various regions before and after the formation of the electrode lines are formed in regions defined by the signal electrode lines and the scanning electrode lines. A structure in which a switching element and a capacitor are formed through a film forming process is obtained. Therefore, in the actual structure of the liquid crystal display device, the connection line 23 shown in the equivalent circuit of FIG.
The sensing element S01 is provided in series between the zero drain electrode 10a and the liquid crystal element 11 having an insulating layer and a capacitor constituting the capacitor section 12.

A detector 17, a coordinate detection signal source 18, and a display signal source 19 are connected to the signal electrode line L, similarly to the configuration shown in FIG. In this example,
The coordinate input device is configured by combining the storage capacitance of the capacitance unit 12 and the liquid crystal of the liquid crystal element 11 as a capacitor and combining this with the sensing element S00. This structure is for the case where the capacitance (C _S ) of the capacitance portion 12 called the storage capacitance is smaller than the capacitance (C _LC ) of the liquid crystal. The capacitance of the capacitance portion 12 and the capacitance of the liquid crystal element 11 are combined. Look like a capacitor. In this case as well, the coordinate signal can be superimposed on the display signal as in the configuration shown in FIG. 11, and a selection circuit for a liquid crystal display such as a shift register for selecting the scanning electrode line G and the signal electrode line L. Can also be used as a selection circuit for inputting coordinates. In the configuration shown in FIG. 11, it is also possible to input the coordinate position from the charging curve of the display signal for the capacitor described with reference to FIGS.
The example in which a thin film transistor is used as the switching element has been illustrated and described above.
Even if an M element is used, a structure having the same function can be obtained, and it goes without saying that the same operation is performed.

[0036] Figure 13 shows an example of applying the structure of the previous example the single net matrix type liquid crystal display device. Unlike the active matrix type liquid crystal display device, the simple matrix type liquid crystal display device is configured by omitting a switching element and driven by primary and secondary electrode lines X and Y provided above and below. Liquid crystal C11, C
The sensing elements S are connected in series to 21, C12, C22 , and so on. Other configurations are the same as those of the above-described embodiment. In the device of this example, the liquid crystal display
Each of the primary electrode lines X and the secondary electrode lines Y is individually or
Electrodes are connected in groups, and display and non-display are performed by time-division driving of each electrode line. When the coordinates are input, the liquid crystal C11, C21, C12, C22,... Function as the charge accumulating section, and thus can be input in the same manner as in the above-described embodiment.

[0037]

As described above, according to the first, second and third aspects of the present invention, the scanning electrode lines and the signal electrode lines are not connected.
AC detection for coordinate detection without affecting the LCD display in between
Pass the signal, and the resistance or impedance of the sensing element
By reading the change, it is wired in a matrix
Light, heat, electromagnetic field,
Or whether a pressure has been applied to the sensing element.
Or can be easily detected from impedance changes
Has an effect. Also, between the scanning electrode line and the signal electrode line
AC detection signal for coordinate detection that does not affect the LCD display
Signal and change the resistance or impedance of each sensing element.
Influence on the LCD display by detecting the change in
Coordinates can be detected completely independently of the LCD display
Has an effect. In addition, the capacitance section is
If the sensing elements are connected in series,
Can be used as a capacitor for sensing element
In this case, the coordinate detection signal is added to the liquid crystal display signal.
Can be overlapped, and in this case, the scanning electrode
Such as a shift register for selecting lines and signal electrode lines.
The selection circuit for liquid crystal display is also used as the selection circuit for coordinate input.
There is an effect that can be used.

According to the fourth aspect of the present invention, AC detection
With a configuration using an AC detection signal of 60 Hz or more as a signal
So that the liquid crystal display does not flicker with the naked eye
To prevent the LCD display from being affected.
Can be

According to the invention described in claim 5, AC detection
10KHz to 1MHz AC detection signal as signal
Because the liquid crystal itself does not respond,
It does not affect the display and considers the ease of circuit design.
It is also preferable in consideration of the above.

[0040]

According to the invention described in claim 6, according to claim 2,
The resistance value of the sensing element described in
Using a phototransistor that changes the
When an object blocks the light incident on the
The resistance of the sensing element corresponding to
The light is blocked by the change in resistance of the sensing element.
The force position can be detected. The invention according to claim 7
According to the AC detection from the signal source for coordinate detection to the signal electrode line
By applying a signal, coordinate detection becomes possible.

[Brief description of the drawings]

FIG. 1A is a circuit diagram showing a basic configuration example of a coordinate input device, and FIG. 1B is a circuit diagram showing a modification of a sensing element used in the circuit shown in FIG.

FIG. 2 is a circuit diagram in which a sensing element and a charge storage unit are connected in series to a power supply.

FIG. 3 is a diagram showing an example of a voltage applied in the circuit shown in FIG. 2;

FIG. 4 is a diagram showing a relationship between current flowing in the circuit shown in FIG. 2 and time.

FIG. 5 is a circuit diagram of one embodiment in which a sensing element is embodied in the circuit shown in FIG. 1;

FIG. 6 is a diagram showing an example of a voltage applied in the circuit shown in FIG. 5;

FIG. 7 is a diagram showing a relationship between a current flowing in the circuit shown in FIG. 5 and time.

FIG. 8 is a circuit diagram showing a modified example of the circuit shown in FIG. 5;

FIG. 9 is a circuit diagram showing an embodiment of the present invention in which a coordinate input device is incorporated in an active matrix liquid crystal driving circuit.

FIG. 10 is a circuit diagram showing a main part of the embodiment shown in FIG. 9;

FIG. 11 is a circuit diagram showing another embodiment of the present invention.

FIG. 12 is a circuit diagram showing still another example of the present invention.

FIG. 13 is a circuit diagram showing an embodiment in which a coordinate input device is incorporated in a simple matrix liquid crystal display device.

FIG. 14 is a circuit diagram showing a configuration example of a conventional coordinate input device.

[Explanation of symbols]

G1, G2, scanning electrode lines, L1, L2, signal electrode lines, X1, X2, ... primary electrode lines, Y1, Y2, ... secondary electrode lines, Z11, Z12, ... connecting lines, Z21, Z22, ... Connection line, C11, C12, ..., C 'capacitor (charge storage unit), S11, S12, ..., S' sensing element, 5, 17 power supply device, G1, G2, ... Scanning electrode line, L1, L2, ... Signal electrode line, 10 switching element, 11 liquid crystal element, 12 capacitance section, 13 scanning circuit (scanning signal source) , 14 signal supply circuit (display signal
Sources) , 15, 16, 23 connection lines, C11, C21, C12, C22 ... liquid crystal,

Claims (7)

(57) [Claims] A plurality of scanning electrode lines and a plurality of signal electrode lines are wired in a matrix, and the scanning electrode lines are connected to a scanning signal line.
The signal electrode line is connected to a display signal source, and a switching element and a pixel electrode are provided in a portion separated by each of the scanning electrode lines and each of the signal electrode lines .
And a liquid crystal driven by each of the pixel electrodes is provided.
And the switching element supplies the scanning electrode line .
A switching operation is performed by the supplied scanning signal, and a display signal supplied to the signal electrode line is supplied to the pixel electrode.
To drive the liquid crystal, the scanning electrode line and the signal electrode
Between the scanning electrode line and the signal electrode line near each intersection with a line , light, heat, a sensing element and a capacitor whose resistance value changes due to an electromagnetic field or pressure are connected in series, and the scanning electrode line and the A coordinate input device, wherein an AC detection signal for detecting coordinates which does not affect the liquid crystal display is passed between the signal electrode lines and the resistance or impedance of each sensing element is detected. 2. A plurality of scanning electrode lines and a plurality of signal electrode lines are wired in a matrix, and the scanning electrode lines are
The issue source, and the signal electrode line are respectively connected to the display signal source, the switching element and the pixel electrode and the capacitor portion separated portion by said each signal electrode line and each scanning electrode line
And a liquid crystal driven by each of the pixel electrodes is provided.
And the switching element performs a switching operation in response to a scanning signal supplied to the scanning electrode line , and transmits a display signal supplied to the signal electrode line to the pixel electrode.
The liquid crystal is driven by supplying the electrode and the capacitor to the
A sensing element whose resistance value changes according to light, heat, an electromagnetic field or pressure is connected in series to the
Coordinates that do not affect the liquid crystal display between the signal electrode lines
An AC detection signal for detection flows, and the resistance of each sensing element is
A coordinate input device for detecting resistance or impedance . A plurality of scanning electrode lines and a plurality of signal electrode lines;
Are arranged in a matrix, and the scanning electrode lines
Signal electrode lines are connected to the display signal source, respectively.
And each of the scanning electrode lines and each of the signal electrode lines are separated.
Switching elements and pixel electrodes are provided in the cut portions.
And a liquid crystal driven by each of the pixel electrodes is provided.
And the switching element supplies the scanning electrode line.
The switching operation is performed by the supplied scanning signal,
A display signal supplied to the signal electrode line is supplied to the pixel electrode.
To drive the liquid crystal and output the switching element.
Light, heat, electromagnetic field or pressure between the edge and the pixel electrode
The sensing element whose resistance value changes
A liquid crystal display between the scanning electrode lines and the signal electrode lines.
AC detection signal for coordinate detection that does not affect
The resistance or impedance of each sensing element.
A coordinate input device characterized in that the coordinate input device emits. 4. The method according to claim 1, wherein said AC detection signal is an AC signal of 60 Hz or more.
4. A detection signal according to claim 1, wherein the detection signal is a detection signal.
2. The coordinate input device according to claim 1. 5. The method according to claim 1, wherein the AC detection signal is 10 kHz to 1 kHz.
Claim, characterized in that a MHz AC detection signal 1
4. The coordinate input device according to any one of claims 3 to 3 . 6. The sensing device according to claim 1, wherein
It uses a phototransistor that changes the resistance.
3. The coordinate input device according to claim 2, wherein: 7. A signal source for coordinate detection is in contact with said signal electrode line.
The method according to any one of claims 1 to 6, characterized by being continued.
2. The coordinate input device according to 1.