JPH09159995A - Active matrix type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to detect position coordinates on the display surface of a touch pen without requiring a touch panel by detecting the position calculation signals supplied to video signal lines and the scanning signals supplied to signal lines by the touch pen. SOLUTION: The position calculation signals are respectively successively supplied by each of the different video signal lines 3 within the fly-back period in the supply of scanning signal to the respective scanning signal lines 2 of the liquid crystal display panel of a transverse electric field system. On the other hand, the position calculation signals supplied to the video signal lines 3 and the scanning signals supplied to the scanning signal lines 2 are detected by the touch pen (detecting sensor) 30 arranged on the display surface side of the liquid crystal display device panel 1. By such constitution, the position coordinates on the display surface of the detecting sensor 30 are calculable from the relation between the timing of the detection output obtd. from the panel 1 and the respective timings of the position calculation signals supplied to the video signal lines 3 and the scanning signals supplied to the scanning signal lines 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device, and more particularly to an active matrix type liquid crystal display device of so-called lateral electric field type.

[0002]

2. Description of the Related Art In an active matrix type liquid crystal display device, which is a so-called horizontal electric field type, transparent substrates are arranged so as to face each other with a liquid crystal layer interposed therebetween, and display is performed in a region corresponding to a unit pixel on the liquid crystal layer side. A unit pixel group, which is provided with an electrode and a reference electrode, is arranged in the y direction through a switching element which is turned on by supplying a scanning signal from each scanning signal line common to the unit pixel group arranged in the x direction. Between the display electrode to which a video signal from each common video signal line is supplied and the reference electrode to which a constant voltage is applied via a reference signal line common to the unit pixel groups arranged in the x direction And a liquid crystal display panel that changes the light transmittance of the liquid crystal layer by an electric field generated parallel to the transparent substrate surface.

Such a liquid crystal display device can recognize a clear image even when observed from a large angle visual field with respect to its display surface, and has come to be known as an excellent so-called wide angle visual field.

[0004]

In such a liquid crystal display device as well, a touch pen or the like is brought into contact with the liquid crystal display device from the display surface side thereof, and information relating to the position coordinates of the touch pen on the display surface is provided in the liquid crystal display device. It is required to have a mechanism for sending the data to the computer.

In this case, usually, a pair of a so-called transparent touch panel and the touch pen, which are arranged so as to overlap with each other on the display surface of the liquid crystal display panel, is used to obtain information on the position coordinates of the touch pen on the touch panel. .

That is, the touch panel extends in the x direction on one surface of each of the opposing surfaces of the transparent resin film which are opposed to each other via spherical spacers arranged in a scattered manner, and the touch panel has a y direction. Electrodes arranged side by side in the same direction are formed, and electrodes arranged side by side in the x direction and extending in the y direction are formed on the other surface, and pressed by the touch pen from the outer surface of the touch panel. The position coordinates of the touch pen can be detected by detecting the electrodes that are in contact with each other.

However, such a touch panel inevitably has a complicated structure, and it has been investigated whether the touch panel can detect the position coordinates of the touch pen with a very simple structure.

The present invention has been devised by finding that this is possible, particularly in a horizontal electric field type liquid crystal display device.

Therefore, an object of the present invention is to provide an active matrix type liquid crystal display device which can detect the position coordinates on the display surface of a touch pen without the need for a touch panel.

[0010]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, the active matrix type liquid crystal display device according to the present invention comprises a horizontal electric field type active matrix type liquid crystal display panel and different video signal lines for each scanning signal line within a blanking period in supplying a scanning signal to each scanning signal line. Means for sequentially supplying position calculation signals to each, and a detection sensor for detecting the position calculation signals supplied to the video signal lines and the scanning signals supplied to the scanning signal lines on the display surface side of the display panel, The position coordinate on the display surface of the detection sensor is calculated from the relationship between the timing of the detection output obtained from the detection sensor, the position calculation signal supplied to the video signal line, and each timing of the scanning signal supplied to the scanning signal line. And means for doing so are provided.

In the thus constructed active matrix type liquid crystal display device, the signals respectively supplied to the scanning signal lines and video signal lines of the horizontal electric field type liquid crystal display panel are outside (display surface side) of the liquid crystal display panel. It has been confirmed that it also creates an electric field.

For example, in a so-called vertical electric field type liquid crystal display panel, which is compared with a horizontal electric field type, transparent electrodes are formed over substantially the entire area of each of the transparent substrates which face each other on the liquid crystal side. The electric field formed by the signals supplied to the scanning signal line and the video signal line is almost terminated by the transparent electrode, and the electric field is not generated until reaching the outside (display surface side) of the liquid crystal display panel.

Therefore, in the horizontal electric field type liquid crystal display panel, first, the position calculation signal is sequentially supplied to each different video signal line within the blanking period in the supply of the scanning signal to each scanning signal line. To do so.

A touch pen (detection sensor) arranged on the display surface side of the liquid crystal display panel detects the position calculation signal supplied to the video signal line and the scanning signal supplied to the scanning signal line. To

With this configuration, the detection sensor of the detection sensor can be obtained from the relationship between the timing of the detection output obtained from the touch panel and the respective timings of the position calculation signal supplied to the video signal line and the scanning signal supplied to the scanning signal line. The position coordinates on the display surface can be calculated.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an active matrix liquid crystal display device according to the present invention will be described below.

[Embodiment 1] FIG. 1 is a schematic configuration diagram showing an embodiment of an active matrix liquid crystal display device for color display.

In FIG. 1, first, there is a horizontal electric field type liquid crystal display panel 1. The liquid crystal display panel 1 includes a transparent substrate 1A and a transparent substrate 1B as its envelope, and a liquid crystal layer is interposed between them. Then, on the surface of the liquid crystal layer of the transparent substrate 1A, which is a so-called lower substrate, the scanning signal lines 2 and the reference signal lines 4 extending in the x direction and juxtaposed in the y direction in the drawing are formed. The scanning signal line 2 and the reference signal line 4 are arranged close to the certain scanning signal line 2 in the -y direction, and are arranged far apart from the reference signal line 2 in the -y direction. The scanning signal line 2 and the reference signal line 4 arranged in proximity to the scanning signal line 2 in the -y direction are sequentially arranged. Further, the video signal line 3 is formed so as to be insulated from these signal lines 2 and 4 and extend in the y direction and be arranged in parallel in the x direction.

The rectangular area surrounded by the scanning signal lines 2 and the reference signal lines 4 and the video signal lines 3 becomes a pixel area, and these pixel areas are arranged in a matrix to form a display section. It has become. A display electrode and a reference electrode are formed in each pixel region, and the thin film transistor TF is formed in a part of the periphery of the pixel region.
T and a storage capacitor Cstg are arranged (those are not shown, but will be described in detail later).

On the surface of the transparent substrate 1B, which is the upper substrate, on the liquid crystal layer side, a light-shielding film having an opening formed in the central portion of each pixel region excluding the peripheral portion is formed, and the opening portion of this light-shielding film is formed. The color filter is formed so as to cover the.

The liquid crystal display panel 1 is provided with a vertical scanning circuit 5 and a video signal driving circuit 6 as its external circuit, and the vertical scanning circuit 5 causes the scanning signal line 2 to operate.
A scanning signal (voltage) is sequentially supplied to each of the video signals, and the video signal driving circuit 6 causes the video signal line 3 to match the timing.
The video signal (voltage) is supplied to.

The vertical scanning circuit 5 and the video signal drive circuit 6 are supplied with power from the liquid crystal drive power supply circuit 7, and the image information from the CPU 8 is supplied to the controller 9 as well.
The display data and the control signal are separately input according to.

The voltage applied to the reference signal line 4 is also supplied from the liquid crystal drive power supply circuit 7. In this embodiment, the voltage applied to the reference signal line 4 is an AC voltage for the purpose of reducing the withstand voltage of the video signal drive circuit 6.

The liquid crystal display device thus constructed is provided with a touch pen (detection sensor) 30. The touch pen 30 is mounted on the upper substrate 1B of the liquid crystal display panel 1 as shown in FIG. 2 (a). The tip can be brought into contact with any position on the display surface.

As shown in FIG. 2B, the touch pen 30 has a pressure sensitive sensor 30A at its tip and an electromagnetic field detecting sensor 30B at the back of this pressure sensitive sensor 30A.

As shown in FIG. 2 (c), the electromagnetic field sensor 30B comprises a sensor having a U-shaped coil, for example. The scanning signal line 2 and the video signal line 3 are arranged on the display surface of the liquid crystal display panel 1. It is possible to detect the electromagnetic field leaked to the.

That is, the horizontal electric field type liquid crystal display panel 1
Basically, as shown in FIG. 3, the liquid crystal layer L is basically formed by an electric field generated between the display electrode 15 and the reference electrode 14 formed on the surface of the transparent substrate 1A in parallel with the transparent substrate surface 1A.
Since the configuration is such that the light transmittance of C is changed, the surfaces of the respective transparent substrates 1A and 1B facing each other with the liquid crystal layer LC interposed therebetween are formed so as to cover most of them. The structure does not require a conductive layer.
This means that the electromagnetic field generated from the scanning signal line and the video signal line is leaked to the outside of the liquid crystal display panel 1 through the transparent substrate without terminating in the conductive layer.

Such a horizontal electric field type liquid crystal display panel 1
Is characterized by what is called a vertical electric field method, in which a pixel electrode and a common electrode made of transparent electrodes are formed on the respective liquid crystal layer side surfaces of transparent substrates which are arranged to face each other with a liquid crystal layer in between. The difference becomes clear by considering the configuration. This is because the electromagnetic field generated from the scanning signal line and the video signal line terminates in the conductive layer forming the pixel electrode and the common electrode, and there is no phenomenon of leakage to the outside of the liquid crystal display panel through the transparent substrate. .

Further, in FIG. 1, the vertical scanning circuit 5 is
By the control signal from the controller 9, the scanning signal line 2
For example, the scanning signals are sequentially supplied from the upper side to the lower side, but in this case, there is a blanking period in the supply of the scanning signals. This blanking period is a cathode ray tube (C
Although it is indispensable when the scanning signal of (RT) is supplied, it is usual that a blanking period is provided in accordance with the scanning signal of the liquid crystal display device.

Further, the controller 9 used in this embodiment
Is configured to supply the position calculation signal to each different video signal line 3 within the blanking period of the scanning signal. The voltage value of this position calculation signal is set to be substantially the same as that of the scanning signal, for example.

FIG. 4 is a flow chart of the controller 9 which performs such an operation. Hereinafter, each step will be described.

Step 1. Of the scanning signal lines 2 arranged side by side in the y direction, for example, the scanning signal is supplied to the scanning signal line 2 at the uppermost line, and the video signal is supplied to all of the video signal lines 3 at the timing. As a result, each pixel corresponding to the scanning signal line is displayed based on the video signal.

Step 2. For example, it is determined whether the scanning signal line 2 which has supplied the scanning signal is the scanning signal line 2 at the bottom line. If it is not the scanning signal line 2 at the lowermost position, the process returns to step 1, the scanning signal is supplied to the scanning signal line 2 on the next line, and the video signal is supplied to all the video signal lines 3 at the timing. Supplied.

In this way, the scanning signal lines are supplied to the scanning signal lines 2 on the bottom line, whereby the display period in one frame ends.

Step 3. Then, at the start of the blanking period, which is the period next to the display period, n, that is, the number of the video signal line 3 is set to 1. The video signal line 3 with n = 1 is, for example, the first video signal line 3 located on the leftmost side.

Step 4. A position calculation signal is supplied to the first video signal line 3 (High). In this case, the position calculation signal is not supplied to the other video signal lines 3 (Lo
w).

Step 5. For example, it is determined whether the video signal line 3 that has supplied the position calculation signal is the rightmost video signal line 3.

Step 6. If it is not the rightmost video signal line 3, n, that is, the number of the video signal line 3 is set to 4.

Then, returning to step 4, the position calculation signal is supplied to the fourth video signal line 3 (High). In this case, the position calculation signal is not supplied to the other video signal line 3 (Low).

The position calculation signal is supplied to the video signal line 3 every three lines in this way, because three pixels adjacent to each other along the scanning signal line 2 are one pixel for color display. On the basis that it is sufficient to select one pixel of

In this way, the display of the next frame is started by finishing the supply of the position calculation signal to every three video signal lines, and the operation described above is repeated from step 1.

With this structure, the touch pen 30 on the surface of the liquid crystal display panel 1 has the scanning signals Vgm supplied to the scanning signal lines 2 in the display period of each frame, as shown in FIG. The position calculation signal Vcn supplied to each video signal line 3 in the blanking period can be detected.

The detection of the scanning signal Vgm and the position calculation signal Vcn by the touch pen 30 is sent to the point controller 32.

The point roller 32 supplies each scanning signal V supplied from the controller 9 to each scanning signal line 2.
Information regarding the timing of gm and the timing of each position calculation signal Vcn supplied to each video signal line 3 is sequentially input, and the scanning signal Vgm detected by the touch pen 30 and the timing of the position calculation signal Vcn are compared. Thus, the calculation for specifying the scanning signal line 2 and the video signal line 3 located under the touch pen 30 is performed. If the specified scanning signal line 2 is the mth line from the top and the video signal line is the nth line from the leftmost side, the position coordinates of the touch pen 30 on the display surface are calculated as (n, m). It has become.

Here, the timing of the scanning signal Vgm and the position calculation signal Vcn detected by the touch pen 30 is the information from the pressure sensor output when the touch pen 30 contacts the surface of the liquid crystal display panel 1. It is decided based on.

The information on the position coordinates (n, m) is sent to the CPU 8, and the CPU 8 displays a cursor on the display surface of the liquid crystal display panel 1 at a portion corresponding to the position. Has become.

At this time, from the point controller 32 to C
By making the format of the position information and click information sent to the PU 8 the same as that of the current pointing device such as a mouse, the CPU 8 can have the same configuration as the conventional one. Further, it can be used in combination with a current pointing device such as a mouse.

According to the liquid crystal display device according to the embodiment described above, first, within the blanking period in the supply of the scanning signal to each scanning signal line 2, the position calculation signal is sequentially supplied to each different video signal line 3. I am trying to supply it.

Then, with the touch pen 30 arranged on the display surface side of the liquid crystal display panel 1, the video signal line 3
The position calculation signal supplied to the scanning signal and the scanning signal supplied to the scanning signal line 2 are detected.

In this way, the relationship between the timing of the detection output obtained from the touch pen 30 and the respective timings of the position calculation signal supplied to the video signal line 3 and the scanning signal supplied to the scanning signal line 2 is used. Touch pen 3
The position coordinates of 0 on the display surface can be calculated.

In this case, as the liquid crystal display panel 1, a horizontal electric field type is used, and signals supplied to the scanning signal line 2 and the video signal line 3 are outside the liquid crystal display panel 1 (display surface side). Since it has been confirmed that an electric field is created, a touch panel that does not require a touch panel can be obtained.

In this embodiment, the position calculation signals supplied to the video signal lines 3 are sequentially supplied to the video signal lines 3 arranged at intervals of several lines, but the present invention is not limited to this. Needless to say, the configuration may be such that each video signal line 3 is sequentially supplied. This is because the position coordinates in the x direction can be calculated more accurately.

In the above-described embodiment, the color liquid crystal display device has been described, but it is needless to say that the present invention is not limited to this and can be applied to a monochrome liquid crystal display device.

An embodiment of the liquid crystal display panel 1 having a more detailed structure will be described below.

FIG. 6 is a plan view showing the structure of each unit pixel of the transparent substrate 1A (corresponding to the portion surrounded by the dotted line in FIG. 1). 7 is a sectional view taken along line VII-VII in FIG. 7, FIG. 8 is a sectional view taken along line VIII-VIII, and FIG.
FIG. 9 shows a cross-sectional view of FIG.

In FIG. 6, on the main surface of the transparent substrate 1A,
A reference signal line 4 extending in the x-direction, and the scanning signal line 2 is formed relatively parallel to the reference signal line 4 in the (-) y direction and relatively apart from the reference signal line 4.

Here, three reference electrodes 14 are integrally formed on the reference signal line 4. That is, two of the reference electrodes 14 are in the y-direction side of a pixel region formed by a pair of video signal lines 3 described later, that is, in the (-) y direction in proximity to the respective video signal lines 3. It is formed to extend to the vicinity of the scanning signal line 2, and the other one is formed between them.

The surface of the transparent substrate 1A on which the scanning signal lines 2, the reference signal lines 4, and the reference electrodes 14 are formed covers the scanning signal lines 2 and the like, and an insulating film 15 made of, for example, a silicon nitride film. (See FIGS. 7, 8 and 9)
Are formed. The insulating film 15 serves as an interlayer insulating film for an intersection with the scanning signal line 2 and the reference signal line 4 for a video signal line 3 described later, and a thin film transistor T
It functions as a gate insulating film for the region where the FT is formed and as a dielectric film for the region where the storage capacitor Cstg is formed.

On the surface of the insulating film 15, first, in the formation region of the thin film transistor TFT, the semiconductor layer 16 is formed.
Are formed. The semiconductor layer 16 is made of, for example, amorphous Si, and is formed on the scanning signal line 2 so as to overlap a portion close to the video signal line 3. As a result, a part of the scanning signal line 2 is
Is also configured as a gate electrode.

On the surface of the insulating film 15 thus formed, as shown in FIG. 6, video signal lines 3 extending in the y direction and arranged in parallel in the x direction are formed. .

The video signal line 3 is integrally provided with a drain electrode 3A formed by extending to a part of the surface of the semiconductor layer 16 of the thin film transistor TFT.

Further, a display electrode 18 is formed on the surface of the insulating film 15 in the pixel area. This display electrode 1
Reference numeral 8 is formed so as to run between the reference electrodes 14. That is, one end of the display electrode 18 also serves as the source electrode 18A of the thin film transistor TFT, extends in the (+) y direction as it is, further extends in the x direction along the reference signal line 4, and then (-) It has a U-shape extending in the direction and having the other end.

In this case, the portion of the display electrode 18 overlapping the reference signal line 4 constitutes a storage capacitor Cstg having the insulating film 15 as a dielectric film between the display electrode 18 and the reference signal line 4. The storage capacitor Cstg has an effect of storing video information on the display electrode 18 for a long time when the thin film transistor TFT is turned off, for example.

The surface of the semiconductor layer 16 corresponding to the interface between the drain electrode 3A and the source electrode 18A of the above-mentioned thin film transistor TFT is doped with phosphorus (P) to form a high concentration layer. The electrode is intended to make ohmic contact. In this case, the high concentration layer is formed on the entire surface of the semiconductor layer 16,
After each of the electrodes is formed, the above structure can be obtained by etching the high-concentration layer other than the electrode formation region using the electrodes as a mask.

Then, in this way, the thin film transistor TF
T, video signal line 3, display electrode 18, and storage capacitor Cs
A protective film 19 made of, for example, a silicon nitride film is formed on the upper surface of the insulating film 15 on which tg is formed (see FIGS. 7, 8, and 9).
Is formed, and the alignment film 20 is formed on the upper surface of the protective film 19 to form the lower substrate of the liquid crystal display panel 1. A polarizing plate 21 is disposed on the surface of the transparent substrate 1A opposite to the liquid crystal layer.

Then, on the liquid crystal side portion of the transparent substrate 1B, as shown in FIG. 7, a light shielding film 22 is formed at a portion corresponding to a boundary portion of each pixel region. This light shielding film 22
Has a function of preventing the thin film transistor TFT from being directly irradiated with light and a function of improving display contrast. This light shielding film 22
Is formed in a region shown by a broken line in FIG. 6, and the opening formed in the region constitutes a substantial pixel region.

Further, a color filter 23 is formed so as to cover the opening of the light-shielding film 22, the color filter 23 has a different color from that of the pixel region adjacent in the x direction, and each color filter 23 has a boundary on the light-shielding film 22. It has a part. A flat film 24 made of a resin film or the like is formed on the surface on which the color filter 23 is formed, and the alignment film 2 is formed on the surface of the flat film 24.
5 are formed. Note that a polarizing plate 26 is disposed on the surface of the transparent substrate 1B opposite to the liquid crystal layer side.

The relationship between the alignment film 20 and the polarizing plate 21 formed on the transparent substrate 1A side and the alignment film 25 and the polarizing plate 26 formed on the transparent substrate 1B side will be described with reference to FIG.

Alignment films 20 and 2 with respect to the direction 207 of the electric field applied between the display electrode 18 and the reference electrode 14.
5, the angle of the rubbing direction 208 is φLC. In addition, the polarization transmission axis direction 20 of one polarizing plate 21
The angle of 9 is φP. The polarization transmission axis of the other polarizing plate 26 is orthogonal to φP. Further, φLC = φP. As the liquid crystal layer LC, a nematic liquid crystal composition having a positive dielectric anisotropy Δε, a value of 7.3 (1 kHz), and a refractive index anisotropy Δn of 0.073 (589 nm, 20 ° C.) is used. Used.

Alignment films 20 and 25 having such a relationship
The structure of the polarizers 21 and 26 and the like is what is called a normally black mode. By generating an electric field E parallel to the transparent substrate 1A in the liquid crystal layer LC, light is transmitted to the liquid crystal layer LC. It is supposed to. However, in this embodiment, the present invention is not limited to such a normally black mode, and it goes without saying that a normally white mode in which light transmitted through the liquid crystal layer LC when no electric field is applied may be the maximum. Absent.

[Second Embodiment] In the first embodiment described above,
The sequential supply of the position calculation signal to the video signal line is configured to be repeated every blanking period in one frame video.

However, it is needless to say that the present invention is not limited to this, and may be configured to be repeated over the blanking period in several frame images. FIG.
It is a flowchart of the controller 9 for making such an operation | movement. Hereinafter, each step will be described.

Step 1. Scanning signals are sequentially supplied in 1-frame video for display. In this case, the y-direction coordinates of the touch pen 30 on the liquid crystal display panel 1 can be calculated.

Step 2. Then, n is set to 1 at the stage of entering the blanking period.

Step 3. A position calculation signal is supplied to the first (= n) th video signal line 3.

Step 4. (Number of video signal lines) / (number of times required for scanning) is 1 (=
n) It is determined whether it is smaller than.

Step 5. If it is not smaller, n is set to 3, and the process returns to step 3 to supply the position calculation signal to the 4 (= n) th video signal line 3.

In this way, the number of video signal lines 3 for sequentially supplying the position calculation signal is (the number of video signal lines; x) /
It is repeated until it becomes equal to (the number of times required for scanning; y).

At this point, the video signal line 3 to which the position calculation signal is supplied does not extend to the entire area of the display surface, but only to a part thereof.

Step 6. Scanning signals are sequentially supplied in the next (or zth) frame image to be displayed. In this case, the y-direction coordinates of the touch pen on the liquid crystal display panel 1 are the same as the coordinates calculated in step 1. This is because the frame switching is performed at a significantly faster speed than the movement of the touch pen.

Step 7. Then, at the stage of entering within the blanking period, n is set to x / y · (z−1).

Step 8. A position calculation signal is supplied to the x / y · (z−1) th video signal line 3. This x / y
The (z-1) th video signal line 3 becomes the video signal line 3 to which the position calculation signal is supplied subsequently to the last video signal line 3 to which the position calculation signal was supplied in the previous frame image.

Step 9. It is determined whether or not the number of the video signal lines 3 supplied with the position calculation signal is larger than x / y (z).

Step 10. If not, add 3 to the number of video signal lines 3 that supplied the position calculation signal,
Returning to step 8, position calculation signals are supplied to the video signal lines 3 corresponding to the added number.

In this way, the process is repeated until the number of video signal lines 3 for supplying the position calculation signal becomes equal to x / y (z).

Even at this point in time, the video signal line 3 to which the position calculation signal is supplied does not extend to the entire area of the display surface, and only a part thereof remains.

Step 11. Next (or p-th)
The scanning signals are sequentially supplied in the frame image to be displayed. Also in this case, the y coordinate of the touch pen on the liquid crystal display panel 1 is the same as the coordinate calculated in step 1.

Step 12. Then, at the stage of entering within the blanking period, n is set to x / y · (y−1).

Step 13. A position calculation signal is supplied to the x / y · (y−1) th video signal line 3. This x / y
The (y-1) th video signal line 3 becomes the video signal line 3 to which the position calculation signal is supplied subsequently to the last video signal line 3 to which the position calculation signal was supplied in the previous frame image.

Step 14. It is determined whether or not the number of video signal lines 3 to which the position calculation signal is supplied is larger than x / y (y).

Step 15. If not, add 3 to the number of video signal lines 3 that supplied the position calculation signal,
Returning to step 15, position calculation signals are supplied to the video signal lines 3 corresponding to the added number.

In this way, the process is repeated until the number of video signal lines 3 for supplying the position calculation signal becomes equal to x.

At this point, the video signal line 3 to which the position calculation signal is supplied extends to the entire area of the display surface.

[0095]

As is apparent from the above description,
According to the active matrix type liquid crystal display device of the present invention, the position coordinates on the display surface of the touch pen can be detected without the need for a touch panel.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an active matrix type liquid crystal display device according to the present invention.

FIG. 2 is a configuration diagram showing an embodiment of a touch pen used in an active matrix type liquid crystal display device according to the present invention.

FIG. 3 is an explanatory diagram showing characteristics of a horizontal electric field type liquid crystal display panel used in an active matrix type liquid crystal display device according to the present invention.

FIG. 4 is a flowchart showing one embodiment of the operation of the controller used in the active matrix type liquid crystal display device according to the present invention.

FIG. 5 is a diagram for explaining signals detected by a touch pen used in an active matrix type liquid crystal display device according to the present invention.

FIG. 6 is a plan view showing a configuration of a unit pixel of a liquid crystal display panel used in an active matrix type liquid crystal display device according to the present invention.

7 is a sectional view taken along line VII-VII in FIG.

8 is a sectional view taken along line VIII-VIII in FIG.

9 is a sectional view taken along line IX-IX in FIG.

FIG. 10 is an explanatory diagram showing a relationship between an alignment film and a polarizing plate of a horizontal electric field type liquid crystal display panel used in an active matrix type liquid crystal display device according to the present invention.

FIG. 11 is a flowchart showing another embodiment of the operation of the controller used in the active matrix type liquid crystal display device according to the present invention.

[Explanation of symbols]

1 ... Liquid crystal display panel, 2 ... Scanning signal line, 3 ... Video signal line, 30 ... Touch pen (detection sensor), Vgm ...
... Scan signal, Vcn ... Position calculation signal.

Claims (6)

[Claims] 1. A unit arranged in the x direction, in which transparent substrates are arranged so as to face each other with a liquid crystal layer interposed therebetween, and display electrodes and reference electrodes are provided in regions corresponding to the unit pixels on the liquid crystal layer side. The display in which the video signal from each video signal line common to the unit pixel group arranged in the y direction is supplied through the switching element turned on by the supply of the scan signal from each scan signal line common to the pixel group The light of the liquid crystal layer is generated by an electric field generated in parallel with the transparent substrate surface between the reference electrode and the reference electrode to which a constant voltage is applied via a reference signal line common to the unit pixel groups arranged in the x direction. An active matrix type liquid crystal display panel for changing the transmittance, a means for sequentially supplying position calculation signals for different video signal lines within a blanking period in supplying the scanning signals to the scanning signal lines, A detection sensor for detecting the position calculation signal supplied to the video signal line and the scanning signal supplied to the scanning signal line on the display surface side of the panel, the timing of the detection output obtained from the detection sensor, and the video signal. Means for calculating the position coordinates on the display surface of the detection sensor based on the relationship between the position calculation signal supplied to the line and the timings of the scanning signal supplied to the scanning signal line. Active matrix liquid crystal display device. 2. The position calculation signal supplied to the video signal line,
2. The active matrix type liquid crystal display device according to claim 1, wherein the video signal lines are sequentially supplied. 3. The position calculation signal supplied to the video signal line,
2. The active matrix type liquid crystal display device according to claim 1, wherein the video signal lines are arranged in sequence every several lines. 4. A liquid crystal display device for color display in which three adjacent pixels forming one pixel for color display are displayed by video signals from respective video signal lines, wherein the position calculation signal is 3 4. The active matrix type liquid crystal display device according to claim 3, wherein the video signal lines are arranged every other line in order. 5. The active matrix type liquid crystal according to claim 1, wherein the sequential supply of the position calculation signal to the video signal line is repeated every blanking period in one frame video. Display device. 6. The active matrix type liquid crystal display according to claim 1, wherein the sequential supply of the position calculation signal to the video signal line is repeated over a blanking period in several frame images. apparatus.