JPH0769529B2 - Display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention provides an input function in which a function as a coordinate input surface is provided on a flat display panel surface as a means for dialogue between an electronic computer and its operator. The present invention relates to an attached display device.

[Conventional technology]

Conventionally, as a display device with an input function in which a plane display panel surface has a coordinate input function, for example, the following one disclosed in Japanese Patent Laid-Open No. 63-81521 by the present applicant has been proposed.

FIG. 8 is a block diagram of the display device with the input function. In FIG. 8, reference numeral 1 denotes a TN mode display liquid crystal cell (flat display panel), each having an X transparent electrode 11 and a Y transparent electrode 12 which are orthogonal to each other. And has a structure such that both ends of each transparent electrode can receive a signal from the outside. 21,22 is X
Driver, 31 and 32 are Y drivers, 4 is an input pen,
It is composed of a pickup coil 40 in which a coil is wound around ferrite and a head amplifier 41. Reference numeral 5 is a memory for writing a pattern to be displayed on the liquid crystal cell 1. A liquid crystal display controller 6 performs display control such as reading pattern data in the X direction corresponding to the selected Y transparent electrode 12 of the liquid crystal cell 1 from the memory 5 and transferring it to the X drivers 21 and 22.

A position detection circuit 7 generates a detection signal from the signal from the input pen 4. 8 is a position detection scanning circuit, 9 is an input / output mode controller, and a liquid crystal display controller 6 in the display mode.
Display data and control signals from X drivers 21, 22, Y
In the position detection mode, various signals from the position detection scanning circuit 8 are supplied to the X drivers 31 and 32 respectively.
21, 22 and Y drivers 31 and 32 play the role of changeover switches to be added respectively. A CPU 10 writes a display pattern in the memory 5 and controls the entire device.

FIG. 9 is a detailed diagram of the configuration relating to the position detection mode in FIG. In the figure, reference numeral 800 denotes a clock generator, the output end of which is through the input / output mode controller 9 the clock input terminal CK of the Y drivers 31 and 32 and the frequency divider 801.
Of the counter 802 and the clock input terminal CK of the counter 802. The output terminal of the frequency divider 801 is connected to the data input terminals D of the Y drivers 31 and 32 and the start terminal S of the counter 802 via the input / output mode controller 9. 803
Is a latch, which latches the output of the counter 802 with a latch pulse (l). 804 is a sine wave generator,
Generates a sine wave with frequency f ₀ . Reference numeral 805 denotes a transistor with a grounded emitter, which generates a sine wave whose phase is 180 ° different from the output sine wave of the sine wave generator 804.

Further, 700 is a bandpass filter whose center frequency is f ₀ . A phase comparator 701 outputs the phase difference between the sine waves input to the two input terminals P1 and P2 as a voltage level from the output terminal PO. 702 is a differential amplifier. Reference numeral 703 is a comparator, which outputs a coincidence pulse when the output of the phase comparator reaches a constant level.

Although 31,32 are the same drivers for Y as those shown in FIG. 8, they actually have an n-stage shift register, and the data input terminal D is driven by the clock pulse of the clock input terminal CK.
The data of is sequentially shifted. The output terminal (Oi) (i = 1 to n) of the driver is connected to the data (D
i) (i = 1 to n) and one of the voltages applied to the voltage application terminals V1, V2, V3, and V4 depending on the value of the alternating current terminal (DF). Figure 12 shows the truth table of the output voltage. In addition, the constant voltage E1, E2, E3 is applied to the voltage application terminals V1, V2, V3.
The DC voltage E4 is applied to the terminal V4 via the input / output mode controller 9 in the display mode, and two sine wave voltages different in phase by 180 ° are applied in the position detection mode.

Further, the internal switch group of the input / output mode controller 9 is, as shown by a broken line in the display mode as shown in FIG.
In the position detection mode, the connection is made as shown by the solid line.

Further, in FIG. 9, Y drivers 31, 32 and Y transparent electrodes 121 to 12 are shown.
Although only n is shown, the X driver and the X transparent electrode are actually provided at positions orthogonal to these, and in the position detection mode, they operate similarly to the Y driver and the Y transparent electrode.

Further, FIG. 10 is a configuration diagram of a liquid crystal cell of a conventional display device with an input function. In the figure, 111, 112, ..., 11k are X transparent electrodes, 12
1,122, ..., 12n is Y transparent electrode, 1000 is X side glass plate, 1001
Is a Y-side glass plate, 1002 is a spacer, and 1003 is a liquid crystal.

FIG. 11 is a view showing a cross section of FIG.

Next, the operation will be described.

A conventional display device with an input function repeats a display mode and a position detection mode in a fixed cycle in a time-division manner. That is, as shown in FIG. 13, one frame period is divided into (n + 2) periods, and the period T ₁ to T _n operates in the display mode, and the periods T _{n + 1} and T _{n + 2} operate in the position detection mode.

First, in the display mode, the internal switch group of the input / output mode controller 9 is connected as shown by the broken line in FIG. 9, and the liquid crystal display controller 6 sequentially reads the data of the pattern to be displayed from the memory 5, which is well known in the art. Display is performed by the voltage averaging drive method. That is, DC voltage (E1, E
2, E3, E4) is set to a bias voltage suitable for the voltage averaging driving method, and the Y transparent electrodes 121, 12 are set for each period T ₁ , T ₂ , ..., T _n.
A selection voltage is sequentially applied to 2, ..., 12n, and a display signal corresponding to the selected Y transparent electrode 12 is applied to the X transparent electrode in each period.
Applied to 11. At this time, the driver outputs at both ends of each X transparent electrode 11 and Y transparent electrode 12 output the same voltage.

Next, the position detection mode will be described with reference to FIG.
In the period T _{n + 1} , the internal switch group of the input / output mode controller 9 is connected as shown by the solid line in FIG. 9 to detect the Y coordinate of the position of the input pen 4.

In the position detection mode, the sine wave voltage V _n sin (2πf ₀ t) generated by the sine wave generator 804 is applied to the V4 terminal of the Y driver 31 and the V4 terminal of the Y driver 32 and the transistor 80
In step 5, a sine wave voltage of −V _m sin (2πf ₀ t) whose phase is shifted by 180 ° is applied. Furthermore, since the DF terminals of the Y drivers 31 and 32 are grounded, the output Oi of the Y drivers 31 and 32 is Oi.
(I = 1 to n) is a sine wave voltage V _m sin when the DC voltage E2 is “H” when the data of the internal shift register is “L”.
(2πf ₀ t) or −V _m sin (2πf ₀ t) is output.

Basic clock C generated by clock generator 800
The start pulse SP (SP in FIG. 14) output by dividing (C in FIG. 14) by (n + 2) by the frequency divider 801 resets the counter 802 to start counting, and the Y drivers 31, 3
It is supplied to the data input terminal D of the second shift register.
After that, each time one basic clock pulse C is generated, the output value of the counter 802 is increased by "1", and in synchronization with it, Y
Since the data in the internal shift registers of the drivers 31 and 32 are shifted one by one, the Y transparent electrodes 12 to which a voltage of ± V _m sin (2πf ₀ t) is applied at both ends are shifted one by one. . That is, assuming that the resistance value of the Y transparent electrode 12 is R ₀ , the Y transparent electrodes 121, 122, ..., 12 m are sequentially (2 V _m / R ₀ ) · sin (2π
A sinusoidal current of f ₀ t) flows.

At this time, the pickup coil 40 of the input pen 4 placed at the X position on the Y transparent electrode 12m is caused by the component of the AC magnetic flux generated by the sinusoidal current flowing through each transparent electrode 12 perpendicular to the liquid crystal cell 1 surface. Electricity is generated. This electromotive force has the same frequency as the sine wave current flowing through the Y transparent electrode 12 but a phase difference of 90 °, and the magnitude of the level is inversely proportional to the distance between the point X and the Y transparent electrode 12 through which the sine wave current flows. It becomes a sine wave.
However, when the current is flowing through the Y transparent electrode 12m at the point X, the distance becomes the shortest, but the magnetic flux of the component perpendicular to the surface of the liquid crystal cell 1 becomes almost zero, so that the output of the pickup coil 40 becomes almost zero. The output signal of the pickup coil 40 is amplified by the head amplifier 41 and passes through the bandpass filter 700 having the center frequency f _{0 in} order to increase the S / N ratio. FIG. 14B shows the output waveform of the bandpass filter 700 when a current is sequentially passed through the Y transparent electrode 12 one by one as described above.

In addition, the Y driver 3 is connected to the two input terminals of the differential amplifier 702.
Each of the sine wave voltage applied to the V4 terminal of 1,32 ± V _m s
Since in (2πf ₀ t) is applied, Y transparent electrode is used for output.
A sine wave proportional to the current flowing through 12 is output (see FIG. 14 (r)).

As can be seen from FIG. 14, the phase of the output signal b of the bandpass filter 700 is the period during which a current is passed from the Y transparent electrodes 121 to 12m and the period during which a current is passed from the Y transparent electrodes 12 (m + 1) to 12n. Then it differs by 180 degrees. Therefore the differential amplifier 702
When the output signal r of the output signal p and the output signal b of the bandpass filter 700 are input to the phase comparator 701, the waveform of the output signal p is
It looks like Figure p. When the reference potential terminal B of the comparator 703 is set to the potential of VR, the comparator 703 outputs the coincidence pulse 1 when the level of the output signal p of the phase comparator 701 becomes VR, and the latch 803 latches the output of the counter 802 at that time. To do.

That is, an alternating current is sequentially applied to the Y transparent electrode 12 for scanning,
When the m-th transparent electrode 12m where the input pen 4 is located scans, the comparator 703 generates a coincidence pulse, and the counter 8
Latch the output value m of 02. The output value of this latch 803 is C
When the PU 10 reads, the Y coordinate of the position of the input pen 4 is detected.

The above operation is performed during the period T _{n + 1} in FIG.
Same operation for T _{n + 2} X drivers 21, 22, X transparent electrode 11
Then, the X coordinate of the position of the input pen 4 is detected.

[Problems to be solved by the invention]

Since the conventional display device with an input function is configured as described above, it is necessary to connect a driver to both ends of the transparent electrode in order to generate an AC magnetic flux, resulting in a large number of parts and an increase in cost. The number of contacts between the electrodes and the substrate increases,
There was a problem that it took time to assemble and adjust.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain an inexpensive display device with an input function that has a small number of parts and does not require assembly.

[Means for solving problems]

A display device according to the present invention includes a flat panel display panel having an XY matrix electrode configuration, and the XY display panel in a display mode.
Display signal applying means for applying a display signal to the matrix electrodes, AC component current applying means for supplying a current having an AC component to at least one of the XY matrix electrodes in the input position detection mode, and magnetic flux detection. Means for detecting the position of the input pen on the display panel based on a signal generated by the magnetic flux detecting means, and a book for alternately repeating the display mode and the input position detecting mode. In a display device comprising a mode switching means for switching the operation mode of the display device,
An electrode lead-out terminal on one side of at least one electrode group of the XY matrix electrodes of the flat display panel is a single terminal shared by all electrodes forming the electrode group, and
It is characterized in that an end portion on a side corresponding to the one side of each of the electrodes constituting the electrode group and the single terminal are respectively connected via a capacitance.

[Action]

In the present invention, because of the above-mentioned configuration, a closed circuit for flowing an AC signal for generating an AC magnetic flux in the input position detection mode without affecting the application of the DC voltage for display is provided in the XY matrix. It is possible to form at least one electrode lead terminal on one side of at least one electrode group of the electrodes.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
The figure shows a display device according to an embodiment of the present invention. In the figure, 111, 112, ..., 11k are X transparent electrodes, and 121, 122 ,.
Transparent electrodes, 1004 and 1006 are the Y transparent electrodes 111, 122, ..., 12n
, And X transparent electrodes 111, 112, ..., 11k, respectively, which are formed by vapor deposition or application of a dielectric member such as barium titanate. 1005 and 1007 are conductive members formed in a film shape with a conductive material such as aluminum so as to be bonded to the dielectric members 1004 and 1006, and these are respectively the X transparent electrodes 111, 112, ..., 11k, , 12n which are shared by the Y transparent electrodes 121, 122, ..., 12n. 1000 is an X side glass plate in which X transparent electrodes 111, 112, ..., 11k are built in, 10
01n is a Y-side glass plate in which Y transparent electrodes 121, 122, ..., 12n are formed, 1002 is a spacer, 1003 is a liquid crystal, and the X-side glass plate 1000 and the Y-side glass plate 1001 are bonded together via a spacer 1002. Liquid crystal 1003 is enclosed between them.

Although not shown, polarizing plates are installed on the X-side glass plate 1000 and the Y-side glass plate 1001.

FIG. 2 is a view showing a cross section of FIG.

FIG. 3 shows an embodiment of a control and drive circuit constructed by using the display liquid crystal cell shown in FIG. 1, in which 100 is a display liquid crystal cell (flat display panel) and 21 is an X driver. ,
31 is a Y driver, 4 is an input pen, 5 is a memory, 6 is a liquid crystal display controller, 7 is a position detection circuit, 8 is a position detection scanning circuit, 91 is an input / output mode controller, 10 is a CPU, 1
1 is an X transparent electrode, 12 is a Y transparent electrode, 40 is a pickup coil (magnetic flux detecting means), and 41 is a head amplifier. Also
50 is a display signal applying means, which is the liquid crystal display controller
The input / output mode controller 91 is composed of X and Y drivers 21, 31. Reference numeral 60 denotes an AC component current applying means, which is constituted by the input / output mode controller 91, the X and Y drivers 21, 31 and the other position detection scanning circuit 8. Reference numeral 70 denotes a position detection means, which is composed of a position detection circuit 7 and a position detection scanning circuit 8. Reference numeral 80 denotes a mode switching means, which is composed of the CPU 10 and the input / output mode controller 91.

The operation will be described below. In each constituent element shown in FIG. 3, the same reference numerals as those of the constituent elements of the conventional example shown in FIG. 8 perform the same operations as those of the conventional example.

In the liquid crystal cell configured as in the present invention, one end of the X transparent electrode 11 is an independent contact, and the other end is a single contact via the dielectric member 1004.
The contacts between both ends and the transparent electrodes are galvanically insulated. The same applies to the Y transparent electrode. When the X driver and the Y driver are operated by the well-known voltage averaging driving method as shown in the conventional example, a display is performed on the display liquid crystal cell 100. As described above, the operation in the display mode is the same as that of the conventional example.

Next, the position detection mode in the liquid crystal cell 100 will be described. An electrical circuit between the both ends of the X transparent electrode is represented as a transparent electrode and a capacitor 1008 connected in series as shown in FIG. As shown in FIG. 5, the impedance of this capacitor has a sufficiently low value at the frequency of the alternating current for generating the alternating magnetic flux for position detection.

Here, if the X driver 21 is caused to operate as a driver on one side in the position detection mode as shown in the conventional example, and the terminals of the input / output mode controller 91 connected to the conductive member 1007 are set to low impedance, The AC magnetic flux necessary for position detection is generated. The operation of detecting the position of the input pen after the AC magnetic flux is generated is the same as in the conventional example.

Moreover, the above-mentioned thing is the same also about a Y transparent electrode.

In the above embodiment, the dielectric member was arranged to form the capacitance component at one end of the transparent electrode of the liquid crystal cell, but a gap is formed between the transparent electrode and the conductive member, and this gap is The liquid crystal may be used as a dielectric substance that forms an electrostatic capacitance between the transparent electrode and the conductive member by arranging the liquid crystal in the sealed portion, and in this case, the same effect as that of the above-described embodiment can be obtained. it can. Here, as a method of controlling the capacitance value, a method of changing the gap interval t as shown in FIG. 6 or a transparent electrode and a conductive member facing each other as shown in FIG. There is a method of adjusting the shape of the part and changing the area of these facing surfaces.

Further, although the flat display panel using the liquid crystal has been described in the above embodiment, a display device having a similar XY matrix electrode configuration may be used, and the same effect as that in the above embodiment can be obtained.

〔The invention's effect〕

As described above, according to the display device of the present invention, X
A flat panel display panel having a -Y matrix electrode configuration, a display signal applying means for applying a display signal to the XY matrix electrodes in a display mode, and at least one of the XY matrix electrodes in an input position detection mode. An AC component current applying unit for supplying a current having an AC component to the electrode group, an input pen having a magnetic flux detecting unit, and position detection for detecting the position of the input pen on the display panel based on a signal generated by the magnetic flux detecting unit. And a mode switching means for switching the operation mode of the display device so as to alternately repeat the display mode and the input position detection mode, the XY of the flat display panel.
The electrode lead-out terminal on one side of at least one electrode group of the matrix electrode is a single terminal shared by all the electrodes forming the electrode group, and on the side corresponding to the one side of each electrode forming the electrode group. Since the end portion and the single terminal are connected via a capacitance respectively, an AC magnetic flux that generates an AC magnetic flux in the input position detection mode without affecting the application of the DC voltage for display. A closed circuit for flowing a signal can be formed by setting the number of electrode extraction terminals on one side of at least one of the XY matrix electrodes to one, and as a result, the number of parts is small and assembly is easy. The effect that a cheap display device with an input function can be obtained is obtained.

[Brief description of drawings]

1 and 2 are views showing the structure of a liquid crystal cell of a display device according to an embodiment of the present invention, and FIG. 3 is a block diagram of a display device using the liquid crystal cell according to the embodiment of the present invention, and FIG. FIG. 5 is an electrical equivalent circuit diagram of a transparent electrode constructed according to the present invention,
FIG. 6 is a diagram showing the electric characteristics of the transparent electrode constructed according to the present invention, FIGS. 6 and 7 are diagrams showing a capacitance forming method in another embodiment of the present invention, and FIGS. FIG. 10 is a block diagram of a conventional display device, FIG. 10 and FIG. 11 are diagrams showing a structure of a conventional liquid crystal cell, FIG. 12 is a truth table for explaining an output of a driver, and FIG. 13 is a conventional display. FIG. 14 is a diagram for explaining the time division operation of the display mode and position detection mode of the device, and FIG. 14 is an output waveform diagram of main signals in FIG. In the figure, 100 is a liquid crystal cell (flat panel display), 11
, 111, 112, ..., 11k are X transparent electrodes, and 121, 122 ,.
Transparent electrode, 1000 is the X side glass plate, 1001 is the Y side glass plate,
1002 is a spacer, 1003 is a liquid crystal, 1004 and 1006 are dielectric members, 1005 and 1007 are conductive members, 5 is a memory, 6 is a liquid crystal display controller, 7 is a position detection circuit, 8 is a position detection scanning circuit, and 91 is an input. Output mode controller, 21 and 31 X and Y drivers, 4 input pen, 40 pickup coil (magnetic flux detecting means), 41 head amplifier, 50 display signal applying means, 60 AC component current applying means, 70 is a position detecting means, 80
Is a mode switching means. The same reference numerals in the drawings indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuji Iwata 8-1-1 Tsukaguchihonmachi, Amagasaki-shi, Hyogo Sanryo Electric Co., Ltd. Applied Equipment Research Laboratory (56) Reference JP-A-61-210397 (JP, A) ) JP-A-57-157339 (JP, A)

Claims (5)

[Claims] 1. A flat display panel having an XY matrix electrode structure, display signal applying means for applying a display signal to the XY matrix electrodes in a display mode, and XY in an input position detection mode. AC component current applying means for supplying a current having an AC component to at least one of the matrix electrodes, an input pen equipped with a magnetic flux detecting means, and an input pen on the display panel based on a signal generated by the magnetic flux detecting means. In a display device comprising position detection means for detecting a position, and mode switching means for switching the operation mode of the display device so as to alternately repeat the display mode and the input position detection mode, the flat display panel An electrode lead-out terminal on one side of at least one electrode group of the XY matrix electrodes is shared by all electrodes forming the electrode group. As a single terminal, and,
A display device, characterized in that an end portion of each electrode constituting the electrode group on the side corresponding to the one side and the single terminal are respectively connected via a capacitance. 2. An end portion on a side corresponding to the one side of all electrodes constituting at least one electrode group of the XY matrix electrodes is integrally coupled by a dielectric member, and the dielectric member is a unitary member. The invention is characterized by being joined to a conductive member that constitutes one terminal.
Display device according to item. 3. A gap is formed between an end portion of all electrodes forming at least one electrode group of the XY matrix electrodes on a side corresponding to the one side and a conductive member forming the single terminal. The display device according to claim 1, wherein the gap is arranged in a liquid crystal enclosing portion, and the liquid crystal constitutes the capacitance. 4. The display device according to claim 3, wherein the value of the capacitance is controlled by changing the length of the gap. 5. The value of the electrostatic capacitance is controlled by adjusting the shapes of the facing portions of the dielectric member and the conductive member and changing the facing surface areas thereof. The display device according to claim 3, which is characterized in that.