JP3443438B2 - Panel with coordinate detection function by pen input - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to relates to a coordinate detection function with the panel by the pen input to be used for information appliances such as personal computers and word processors.

[0002]

2. Description of the Related Art A tablet device with a display function has been put into practical use as a means for inputting handwritten characters and graphics into an information device such as a computer and a word processor.

In this tablet device with a display function, for example, an electrostatic induction type tablet panel is laminated on a liquid crystal panel and pen input information detected by the upper tablet panel is displayed on the lower liquid crystal panel. The grid-like detection electrodes of the tablet panel appear to overlap with the image displayed on the liquid crystal panel and display quality deteriorates.

Therefore, as a device for eliminating such drawbacks, a display panel with a pen input function has been proposed which shares the display electrode and drive circuit of the liquid crystal panel and the coordinate detection electrode and drive circuit of the electrostatic induction type tablet. There is.

FIG. 7 is a diagram showing an example of the display panel with a pen input function, and a duty type liquid crystal panel is used as the liquid crystal panel. This duty type LCD panel
A liquid crystal panel (hereinafter, simply referred to as a liquid crystal panel) 1 includes n common electrodes (Y _{1 to} Y _n ) arranged in rows and m arranged in columns.
It has a pixel matrix of n × m dots in which liquid crystal is filled between the segment electrodes (X _{1 to} X _m ) of the book. The liquid crystal panel 1 having the above-described configuration is
It functions as a display panel during the display period in which the frame is time-divided, and as a tablet during the coordinate detection period.

Reference numeral 2 is a common drive circuit for driving the common electrode Y, 3 is a segment drive circuit for driving the segment electrode X, and 4 is a display control signal from the display control circuit 5 and a detection control signal from the detection control circuit 6. A switching circuit for switching and selecting and transmitting to the common drive circuit 2 and the segment drive circuit 3, 8 is a detection pen for detecting the input position, 1
Reference numerals 0 and 11 denote an x-coordinate detection circuit and a y-coordinate detection circuit for obtaining the coordinates of the tip of the detection pen 8 based on a detection signal from the detection pen 8, and 7 denotes the switching circuit 4, the x-coordinate detection circuit 10 and the y-coordinate detection circuit 11 described above. Is a control circuit for controlling the image display and coordinate detection, and 12 is a DC power supply circuit.

FIG. 9 shows a detection pen 8 on the liquid crystal panel 1.
FIG. 4 is a partial cross-sectional view of the case where is placed. The detection electrode 13 of the detection pen 8 and the common electrode Y and the segment electrode X of the liquid crystal panel 1 are electrostatically coupled (the segment electrode X is not shown in the electrostatic coupling state). Here, the degree of electrostatic coupling with each of the electrodes X and Y is maximum between the electrodes located directly below the detection pen 8 and becomes smaller as the distance from the detection pen 8 increases.

During the coordinate detection period, a scanning voltage is sequentially applied to the segment electrode X and the common electrode Y based on the detection control signal from the detection control circuit 6 to perform scanning. Then, as shown in FIG. 9, the detection electrode 13 of the detection pen 8 which is electrostatically coupled to each of the electrodes X and Y is detected with a waveform as shown in FIG. 10A depending on the degree of electrostatic coupling. The signal is triggered. This detection signal is processed by the operational amplifier 9, the differential circuit of the coordinate detection circuits 10 and 11 and the comparator to obtain a pulse signal as shown in FIG. 10C via the signal having the waveform shown in FIG. 10B. Then, the tip coordinates of the detection pen 8 are detected from the timing T when this pulse signal is generated.

FIG. 11 shows each electrode X, of the liquid crystal panel 1.
The connection state of the Y electrode terminal and the common drive circuit 2 and the segment drive circuit 3 is shown.

The liquid crystal panel 1 has a common electrode Y on the surface.
The glass substrate 15 on which the segment is formed and the segment electrode X on the surface
The glass substrate 16 on which the electrodes are formed is laminated at a predetermined interval with the electrode formation side facing each other. In the figure, the area inside the rectangle A ₁ A ₂ A ₃ A ₄ is a display area in which the segment electrodes X and the common electrodes Y arranged in parallel face each other with the liquid crystal interposed therebetween.

The electrode terminals of the electrodes X and Y protruding from the display area A ₁ A ₂ A ₃ A ₄ to the periphery are narrowed down in a fan shape (hereinafter,
This fan-shaped electrode terminal is called a fan-shaped electrode), tape automated bonding (TAB) film (TAB ₁ ~
They are insulated from each other and connected to the fine wire electrode group on the TAB ₇ ) by a crimping method. And TAB film (T
The thin linear electrodes on AB _{1 to} TAB ₇ ) are liquid crystal driving LSIs.
(Large-scale integrated circuit) It is connected to the pads of (LSI _{1 to} LSI ₇ ) by bonding.

Thus, the liquid crystal driving LSI (LSI _{1 to} LS
TAB film I ₃₎ is mounted (TAB ₁ ~TAB
₃ ) is fixed on the printed circuit board to form the common drive circuit 2. Similarly, a liquid crystal drive LSI (LS
TAB film (TAB) on which I _{4 to} LSI ₇ ) are mounted
_{4 to} TAB ₇ ) are fixed on the printed circuit board to form the segment drive circuit 3.

[0013]

However, the conventional display panel with a pen input function has the following problems.

FIG. 12 shows the display area A ₁ A ₂ in FIG.
It is a partially enlarged view of the vicinity of one side A ₁ A ₄ of A ₃ A _4. Consider a case where the tip of the detection pen 8 is placed in a circle P ₂ in the central portion of the liquid crystal panel 1 and in a circle P ₁ in the peripheral portion of the liquid crystal panel 1.

First, when inside the circle P ₂ , the main range in which the detection electrode 13 of the detection pen 8 is electrostatically coupled to the electrodes X and Y is a region surrounded by the circle R ₂ (region R). ₂ ). In this region R ₂ , the common electrodes Y are arranged completely in parallel. Therefore, in the coordinate detection period, when scanning is sequentially performed from the common electrode Y _{1 at one} end toward the common electrode Y _n at the other end at a constant speed, the generation timing T (FIG. 10 (c)) is proportional to the actual y-coordinate of the tip of the detection pen 8, the y-coordinate detection circuit 11 can easily detect the y-coordinate of the tip of the detection pen 8.

Therefore, for example, when the tip of the detection pen 8 moves above the center H ₂ -H ₂ ′ of the liquid crystal panel 1, the actual y coordinate “y” and the detected y coordinate “of the tip of the detection pen 8”. The relation with " _yd " is a straight line except for the end portion as shown by the solid line J in FIG. Incidentally, the non-linear portion at the end portion is due to the peripheral effect, but since it is not directly related to the present invention, it will not be mentioned here.

However, when the tip of the detecting pen 8 is located within the circle P ₁ in the peripheral portion of the liquid crystal panel 1, the situation is different from the above case. In this case, the main range in which the detection electrode 13 of the detection pen 8 is electrostatically coupled to the electrodes X and Y is the region R ₁ surrounded by the circle R ₁ and the parallel common electrodes inside the one side A ₁ A _4. Not only Y but outer fan electrode 1
This is an area including 7 as well. Therefore, when scanning is performed at a constant speed from the common electrode Y _{1 at one} end to the common electrode Y _n at the other end, the waveform of the detection signal induced in the detection electrode 13 by the action of the voltage of the fan-shaped electrode 17. Is distorted, the generation timing T of the detection signal induced in the detection electrode 13 is not proportional to the actual y coordinate "y" of the tip of the detection pen 8.

Therefore, when the tip of the detection pen 8 moves on the periphery H ₁ -H ₁ 'of the liquid crystal panel 1, the actual y coordinate "y" and the detected y coordinate "y _d " are broken lines in FIG. It becomes non-linear as indicated by K and deviates from the true y coordinate value.

The above also occurs when the segment electrode X is scanned.

Here, the distortion of the broken line K shown in FIG. 13 is caused by the TAB films (eg, TAB ₁ and TA) which are adjacent to each other.
It occurs before and after the boundary of the fan-shaped electrode 17 connected to B ₂ ). The amount of strain reaches several dots, though it varies depending on the bending angles of the electrodes X and Y in the display area A ₁ A ₂ A ₃ A ₄ and the fan-shaped electrodes 17 connected to the electrodes X and Y.

Such a distortion does not cause any problem when the error between the position designated by the detection pen 8 and the detected coordinates has an allowable range such as the cursor designation or the icon designation.
However, when the error between the designated position and the detected coordinates does not have an allowable range as in the case of character input, the shape of the input character is distorted, which causes a problem that the recognition rate decreases. As a result, the purpose of use around the display area A ₁ A ₂ A ₃ A ₄ is limited.

Normally, such a distortion of the detected coordinates is corrected by a CPU (central processing unit) or the like in order to bring it closer to the correct coordinates, but it is corrected to the level of linearity shown by a solid line J in FIG. The problem is that it is difficult.

[0023] It is an object of the present invention is to provide a coordinate detection function with the panel by the pen input capable of increasing the coordinate detection accuracy can have you the original coordinate detection <br/> region periphery.

In order to achieve the above object, a panel with a coordinate detecting function by pen input according to the present invention has a coordinate detecting area in which first electrodes arranged in parallel and second electrodes arranged in parallel are arranged in a grid pattern. Drive having a panel having a sensor, a detection pen having a detection electrode at its tip that is electrostatically coupled to the first electrode and the second electrode of the panel, and a driving integrated circuit for driving the first electrode group. A circuit and a second drive circuit including a drive integrated circuit for driving the second electrode group, and the first electrode group and the second electrode circuit based on a detection control signal from the first drive circuit and the second drive circuit. in the coordinate detection function with the panel by the pen input for detecting the coordinates of the tip of the detection pen on the panel based on the detection signal induced at the detection electrode of the detection pen upon successively scanning the second electrode group, the panel Wherein the outer side in the coordinate detection area
Formed where the first and second electrodes do not exist
In addition, it is characterized by including an auxiliary electrode connected to a predetermined voltage source .

Further , the coordinates by the pen input according to the present invention
The panel with a detection function, the panel is a display panel,
The first electrode group and the second electrode group are the front surface of the display panel.
The first drive circuit and the second drive circuit are also used as an indicating electrode group.
The drive circuit of is also used as the drive circuit of the display panel.
It is characterized in that that.

Further, the coordinate detection function with the panel by the pen input according to the present invention, the table having a display area and a second electrode in parallel with the first electrode in parallel, which are arranged in a grid pattern
A first drive comprising a display panel, a detection pen having at its tip a detection electrode electrostatically coupled to the first electrode and the second electrode of the display panel, and a drive integrated circuit for driving the first electrode group. A display circuit and a second drive circuit including a drive integrated circuit for driving the second electrode group ,
Display control by the first drive circuit and the second drive circuit
Control the first electrode group and the second electrode group based on a signal
While displaying the image on the display panel, the coordinate detection period
In between, a detection signal induced in the detection electrode of the detection pen when the first electrode group and the second electrode group are sequentially scanned based on the detection control signal by the first drive circuit and the second drive circuit is added. in the coordinate detection function with the panel by the pen input for detecting the coordinates of the tip of the detection pen in the display panel on the basis, outside the display area of the display panel
On the side where the first electrode and the second electrode do not exist.
And an auxiliary electrode formed so as not to face the
A scanning voltage is applied to the auxiliary electrode based on the control signal.
The auxiliary electrodes as if they were in the first and second electrode groups.
Auxiliary electrode drive that operates as if it were the outermost electrode
It is characterized by having a circuit .

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

In the present invention, the pen input is performed by the electrostatic coupling method.
The first electrode outside the coordinate detection area of the panel
And an auxiliary electrode formed at a position where the second electrode does not exist
Is grounded or connected to a DC power supply with low AC impedance.
By being continued, the first electrode and the second electrode are
A fluorescent light type backlight that leaks from a non-existing location.
AC electric field from electric parts such as
Are shielded. Thus, it is induced in the detection electrode of the detection pen.
Noise is prevented, and the input coordinates of the detection pen are
False detection is prevented .

[0033]

Further, in the present invention, the display panel and the coordinate detection are used.
The output device can be integrated.

Further, according to the present invention, the electrostatic coupling method is used.
Scan input by the auxiliary electrode drive circuit
Pressure is applied to the outer first electrode in the display area of the display panel.
And the auxiliary electrode formed where the second electrode does not exist
When applied, it is as if the first and second electrodes of the display panel
It is operated as if it were the outermost electrode in the group. did
If there is a detection pen in the corner of the display area
The distortion of the detection signal induced in the detection electrode of the detection pen.
Is eliminated and the coordinate detection precision in the corner of the display area is eliminated.
The degree is increased.

At this time, the auxiliary electrodes do not face each other.
It is shaped like Therefore, the scanning voltage is
When applied to the auxiliary electrode, the display layer of the display panel is electrically charged.
No pressure is applied to prevent adverse effects on the image display and display layer.
Be stopped.

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

EXAMPLES Hereinafter, coordinate detection by pen input according to the present invention
An example of a functional panel will be described in detail with reference to the drawings .

In the embodiment described below, a pen input
As a panel with a mark detection function, FIG. 7 , FIG. 11 and FIG.
Regarding the improvement of the display panel peripheral portion of the display panel with a pen input function as shown in FIG. 7 , the configuration other than the display panel peripheral portion is exactly the same as in FIGS. Therefore, in each of the following embodiments, the constituent members other than the peripheral portion of the display panel are designated by the member numbers and the member numbers in FIGS. 7 , 11, and 12, and the detailed description thereof is omitted.

<First Embodiment> In this embodiment, FIG.
The electrostatic detection between the fan-shaped electrode 17 and the detection electrode 13 of the detection pen 8 in 2 is eliminated to improve the coordinate detection accuracy.

FIG. 1 is a partially enlarged view of a peripheral portion of a liquid crystal panel 1 which constitutes a display panel with a pen input function of this embodiment. In the liquid crystal panel 1 of the present embodiment, the fan-shaped electrode 17 outside the one side A ₁ A _{4 of the} display area A ₁ A ₂ A ₃ A ₄ is covered with the shield electrode 21, and the detection pen based on the voltage of the fan-shaped electrode 17 is used. The action of 8 on the detection electrode 13 is blocked.

The shield electrode 21 is, as shown in FIG.
It is formed on the lower surface of the protection panel 23 by a technique such as vapor deposition or sputtering using a metal such as aluminum or ITO (indium oxide). The shield electrode 2
The formation location of 1 is not limited to the lower surface of the protection panel 23, but may be the upper surface of the glass substrate 15 or the surface of the polarizing plate 22 on which the common electrode Y is formed on the lower surface. In addition, a thin metal plate may be sandwiched between the glass substrate 15 and the polarizing plate 22 to form the shield electrode 21 regardless of the technique such as vapor deposition or sputtering. Alternatively, it may also serve as a metal chassis that is housed when it is mounted on the application device.

As a simple method, a powder of silver, copper, carbon or the like, which is made into a paste with a binder, may be attached by a printing technique such as screen printing or spraying. At that time, the shield electrode 21 formed by the above-mentioned printing technique may be formed on the upper surface of the protective panel 23 so as to also serve as a frame-shaped decorative printing which is formed around the protective panel 23 later or the printing of the base thereof.

The shield electrode 21 is usually formed in parallel with the segment electrode X or the common electrode Y as shown in FIG. However, the present embodiment is not limited to this, and a free shape can be selected within a range in which the above-described shielding effect can be exhibited depending on the arrangement of each component and the design shape.

Since the shield electrode 21 shields the action of the detection pen 8 on the detection electrode 13 due to the voltage of the fan-shaped electrode 17, the voltage applied to the other electrodes such as the segment electrode X and the common electrode Y. Normally grounded to prevent voltage induced by.

As described above, in this embodiment, each side (A ₁ A ₂ ), (A ₂ A ₃ ), (A _{3 of the} display area A ₁ A ₂ A ₃ A ₄ is
A ₄ ), (A ₄ A ₁ ), which is outside the electrodes X and Y and which connects the corresponding TAB films (TAB ₁ to TAB ₇ ), is covered with the shield electrode 21, Fan-shaped electrode 17
It is possible to block the action of the detection pen 8 on the detection electrode 13 due to the voltage. Therefore, no detection signal is induced in the detection electrode 13 of the detection pen 8 due to the voltage of the fan-shaped electrode 17.

As a result, when the tip of the detection pen 8 is placed in the circle P ₁ in the peripheral portion of the liquid crystal panel 1, the range in which the detection electrode 13 of the detection pen 8 is electrostatically coupled to each electrode X, Y Is an area inside the one side A ₁ A ₄ of the area R ₁ (common electrodes Y arranged in parallel). Therefore, when scanning the common electrode Y, the relationship between the actual y coordinate "y" of the tip of the detection pen 8 and the detected y coordinate "y _d " is in direct proportion. However, in that case, the range in which the detection electrode 13 is electrostatically coupled becomes narrower than the region R ₂ in the central portion of the liquid crystal panel 1, and the voltage of the detection signal induced in the detection electrode 13 becomes low.

By the way, the shield electrode 21 in the present embodiment.
Not only serves as the above-described shielding effect, but also functions as an auxiliary electrode for the segment electrode X and the common electrode Y by electrostatically coupling with the detection electrode 13 of the detection pen 8. In other words, it has a wider function than the function that comes from the name "shield electrode". The function as the auxiliary electrode will be described below.

In the display panel with a pen input function according to the present embodiment, when the tip of the detection pen 8 is placed within the circle P ₁ in the peripheral portion of the liquid crystal panel 1, the detection electrode 13 and the segment electrode X are electrostatically coupled. The combined range is not symmetrical in the X-axis direction with respect to the center of the circle R ₁ . Therefore, the detection signal induced in the detection electrode 13 of the detection pen 8 when the segment electrode X is scanned during the x-coordinate detection period is as shown in FIG.
The waveform is not symmetrical with respect to the time axis direction (that is, in the X axis direction), but is a biased waveform. Therefore, the center position of the pulse signal obtained by the processing by the operational amplifier 9, the differential circuits of the coordinate detection circuits 10 and 11 and the comparator is deviated from the original position.

[0054] Therefore, in this embodiment, the detection electrode 1 when placing the tip of the detection pen 8 in the circle P ₁
In order to correct the bias in the range in which 3 electrostatically couples with the segment electrode X, the shield electrode 21 is set to x during the x coordinate detection period.
It is operated as a coordinate scanning electrode.

That is, a shield electrode drive circuit (not shown) is provided separately from the common drive circuit 2 and the segment drive circuit 3 and, based on the detection control signal from the detection control circuit 6 during the x coordinate detection period. A scanning voltage is also applied to the shield electrode 21 at a predetermined timing. Thus, the segment electrode X ₁ at one end upon sequential scanning voltage toward the segment electrode X _m of the other end is applied, before applying the scanning voltage to the segment electrode X ₁ of the one end of the segment electrode X ₁ The scanning voltage is applied to the shield electrode 21 located outside. On the other hand, the display areas A ₁ A _{2 of the} liquid crystal panel 1 are
A shield electrode (not shown) is also provided near one side A ₂ A _{3 of} A ₃ A _{4 which} faces one side A ₁ A ₄ (however, in the case of the liquid crystal panel 1 having the configuration of FIG. comprising Te fan electrode is not), after applying a scanning voltage to the segment electrode X _m in the other end, it is to apply a scan voltage to the shield electrode positioned outside the segment electrode X _m.

[0056] In other words, in FIG. 7, the segment electrode X _{m + 1} disposed on the outer side of one segment electrode X _m providing the segment electrodes X ₀ outside the segment electrodes X _1,
The (m + 2) segment electrodes X are sequentially scanned.

Thus, in the x-coordinate detection period, the range in which the detection electrode 13 is electrostatically coupled to the segment electrode X when the tip of the detection pen 8 is placed within the circle P ₁ in the peripheral portion of the liquid crystal panel 1. Is the area within the circle R ₁ .
Therefore, when the tip of the detection pen 8 is in the peripheral portion of the liquid crystal panel 1, the detected coordinates are prevented from being displaced inward from the actual coordinates.

That is, the shield electrode 21 in this embodiment.
Acts as a shield electrode that literally shields the action of the detection pen 8 on the detection electrode 13 due to the voltage of the fan-shaped electrode 17 in the y-coordinate detection period, while it is electrostatic in the peripheral portion of the liquid crystal panel 1 in the x-coordinate detection period. It functions as an auxiliary electrode for correcting the deviation of the coupling range.

As described above, the scanning voltage applied to the shield electrode 21 in the x coordinate detection period is generated by the shield electrode drive circuit based on the detection control signal from the detection control circuit 6. However, the scanning voltage applied to the shield electrode 21 and the scanning voltage applied to the segment electrode X are not always the same voltage due to the difference in the installation location and the structure with the segment electrode X. Normally, the shield electrode 21 is formed at a position closer to the detection pen 8 than the segment electrode X.
The scan voltage may be lower than the scan voltage applied to the segment electrode X.

In the above description, the vicinity of one side A ₁ A ₂ in the display area A ₁ A ₂ A ₃ A ₄ of the liquid crystal panel 1 has been described, but the other sides (A ₂ A ₃ ) and (A ₃ a _4), and has exactly the same structure even in the vicinity of (a ₄ a _1).

If the shield electrode 21 is used only to obtain the shield effect, its shape may be a frame shape. However, the segment electrode X and the common electrode Y
If it is also used as an auxiliary electrode of the liquid crystal panel 1, the shape is made rectangular and each side (A ₁ A ₂ ), (A ₂ A ₃ ), in the display area A ₁ A ₂ A ₃ A ₄ of the liquid crystal panel 1, It is preferable that each of (A ₃ A ₄ ), (A ₄ A ₁ ) is independently formed.

In the above embodiment, as shown in FIG. 1, the liquid crystal panel 1 has a display region (inside of sides A ₁ A ₄ ) and a shield electrode 21 (outside of sides E ₁ E ₄ ). A small gap is provided between them. The reason why the slight gap is provided is as follows.

That is, if the gap is set to "0", and the shield electrode 21 is formed opaque, the liquid crystal panel 1
Of the shield electrode 21 and the display area A generated in the manufacturing process of
A slight positional deviation or angular deviation from each side of ₁ A ₂ A ₃ A ₄ will be noticeable when the backlight is lit, and the quality of the product will be degraded. In addition, as shown in FIG.
1 is formed at a position higher than the segment electrodes X and the common electrodes Y located on the inner side, the outermost pixel row when the liquid crystal panel 1 is viewed from an oblique angle is the shield electrode 21.
This is because the display becomes difficult to see due to the shadow of.

Another reason is that, as described above, the electrostatic coupling range of the detection electrode 13 is narrowed when the tip of the detection pen 8 is positioned within the circle P ₁ and is induced in the detection electrode 13. This is because the voltage of the detection signal becomes low and it becomes impossible to detect the y coordinate in an extreme case. Therefore, the display area A
A gap is provided between ₁ A ₂ A ₃ A ₄ and the shield electrode 21 to expose a part of the fan-shaped electrode 17 and widen the electrostatic coupling range with the detection electrode 13. However, in that case, of course, the action of the exposed fan-shaped electrode 17 lowers the coordinate detection accuracy. Therefore, a compromise between the detection accuracy of the coordinates due to the exposure of the fan-shaped electrode 17 and the voltage increase of the detection signal is found, and the display area of the liquid crystal panel 1 and the shield electrode 21 are found.
It is necessary to set the interval between and.

As a result of experiments by the inventors, the fan-shaped electrode 17
It has been found that the influence of the fan-shaped electrode 17 is relatively small if the gap is about 1 mm, although it depends on the opening angle of the.
If the application around the liquid crystal panel 1 is limited, the above interval can be used up to about 3 mm.

<Second Embodiment> In this embodiment, the segment electrode X and the common electrode Y are connected to the display area A.
₁ A ₂ A ₃ A ₄ is extended to the outside to improve coordinate detection accuracy.

FIG. 3 is a partially enlarged view of the peripheral portion of the liquid crystal panel 1 which constitutes the display panel with a pen input function of this embodiment. In the liquid crystal panel 1 in this embodiment,
The end of the common electrode Y is linearly extended by "l" in the direction in which the common electrode Y extends outward from one side A ₁ A ₄ of the display area A ₁ A ₂ A ₃ A _4. (Hereinafter, the electrode that extends the end of the common electrode Y is referred to as an extension electrode 25). Then, the fan-shaped electrode 17 is provided outside the side C ₁ C ₄ which is outside the one side A ₁ A ₄ by the distance “l”.

At this time, the distance "l" is set to the detection pen 8
If the detection electrode 13 is set longer than the radius of a circular region where the detection electrode 13 can be electrostatically coupled to the electrodes X and Y when the tip of the is positioned on the outermost pixel, as shown in FIG. ,
Even if the tip of the detection pen 8 is in the circle P ₃ in the peripheral portion of the liquid crystal panel 1, the sector electrode 17 does not exist in the region R ₃ where the detection electrode 13 is electrostatically coupled to the common electrode Y. Therefore, a detection signal is not induced in the detection electrode 13 of the detection pen 8 due to the voltage of the fan-shaped electrode 17.

As a result, the relationship between the actual y coordinate "y" of the tip of the detection pen 8 and the detected y coordinate "y _d " when scanning the common electrode Y is in direct proportion. At that time, the detection electrode 13 is electrostatically coupled to the common electrode Y in the circular region R ₃ which is the same as the region R ₂ in the central portion of the liquid crystal panel 1. Therefore, the detection signal induced in the detection electrode 13 is detected. The voltage of is not low.

The extension electrode 25 is preferably made of the same material as the segment electrode X and the common electrode Y. That is, in the case of a transmissive liquid crystal panel that irradiates from the back side of the liquid crystal panel 1, the same I as the electrodes X and Y is used.
A transparent electrode made of TO or the like is suitable. In the case of a reflection type liquid crystal panel which irradiates from the pen input side of the liquid crystal panel 1, a transparent electrode is suitable for the extension electrode 25 extending the electrode on the pen input side (common electrode Y in this embodiment). The extension electrode 25 for extending the back side electrode (segment electrode X in this embodiment) is made of the same material (for example, metal) as the back side electrode. As described above, by making the material of the extension electrode 25 the same as the material of the electrodes X and Y to be extended, it is not necessary to provide a special extension electrode forming step, and the productivity is excellent.

If the extension electrode 25 has the same width as the corresponding electrodes X and Y, a scanning voltage is applied to the extension electrode 25 and the electrode connected to the extension electrode 25 (common electrode Y in FIG. 3). When applied, the output of the detection signal induced in the detection electrode 13 of the detection pen 8 by the voltage of the extension electrode 25 and the detection induced in the detection electrode 13 by the voltage of the common electrode Y connected to the extension electrode 25 It is the same as the signal output, which is desirable in terms of coordinate detection accuracy.

By providing the upper extension electrode 25, the following effects can be obtained. That is, the lengths of the segment electrode X and the common electrode Y are long even if there is an error in the alignment between the glass substrate 15 on which the common electrode Y is formed and the glass substrate 16 on which the segment electrode X is formed. Since there is a margin, the pixel rows in the peripheral portion of the display area will not be scraped.

It is desirable that no other electrode is provided behind the extension electrode 25. If the need arises, it is necessary to keep the extension electrode 25 and the back electrode at the same potential so that no electric field is applied to the liquid crystal between the two electrodes. Otherwise, an undesired display may occur in the area of the extension electrode 25 when an electric field is applied, or the liquid crystal may be electrolyzed in the case of a DC electric field.

Further, the extension electrode 25 is the TAB film (T film) in each segment electrode X and common electrode Y.
The above-mentioned effect can be obtained not only by providing the end portion on the side connected to AB _{1 to} TAB ₇ ) but also by providing the end portion on the opposite side.

<Third Embodiment> In this embodiment, the second
It is intended to further stabilize and improve the accuracy of the display panel with a pen input function in the embodiment.

As described above, when the extension electrodes 25 are formed around the display area A ₁ A ₂ A ₃ A ₄ in the liquid crystal panel 1, outside the four corners of the display area A ₁ A ₂ A ₃ A _4. There is a blank area without an extension electrode. Therefore, when the tip of the detection pen 8 is positioned at the four corners of the display area A ₁ A ₂ A ₃ A ₄ , the range in which the detection electrode 13 of the detection pen 8 is electrostatically coupled with each electrode X, Y becomes narrow. Detection accuracy is lowered.

Therefore, as shown in FIG. 4, a square auxiliary electrode having a length "l" of one side of the extension electrode 25 is formed in a blank portion where no extension electrode is provided at the four corners of the display area A ₁ A ₂ A ₃ A _4. 26 is arranged so that an electrostatic coupling can be formed with the detection electrode 13 of the detection pen 8. An auxiliary electrode drive circuit (not shown) is provided separately from the common drive circuit 2 and the segment drive circuit 3, and the auxiliary electrode 26 is also scanned at a predetermined timing based on the detection control signal from the detection control circuit 6. By applying a voltage, each auxiliary electrode 26 is operated like the common electrode Y ₀ , the common electrode Y _{n + 1} or the segment electrode X ₀ , the segment electrode X _{m + 1} . In this way, by operating each auxiliary electrode 26 as a part of each electrode X, Y group, the coordinate detection accuracy at the corner of the display area A ₁ A ₂ A ₃ A ₄ is improved.

Further, the auxiliary electrode 26 has the following effects. That is, on the back surface of the liquid crystal panel 1, electric parts such as a fluorescent lamp type backlight operating with a relatively high AC voltage or pulse voltage are arranged. An AC electric field from these electric components leaks from a blank portion in the corner of the display area A ₁ A ₂ A ₃ A ₄ without the extension electrode 25 and directly acts on the detection electrode 13 of the detection pen 8 to generate unnecessary noise. It will induce. However, as described above, if the auxiliary electrode 26 is arranged in the blank portion, the AC electric field from the electric component is shielded by the auxiliary electrode 26. Therefore, erroneous detection due to noise induced in the detection electrode 13 of the detection pen 8 is prevented. In order to obtain such an effect, it is necessary to ground the auxiliary electrode 26 or connect it to a DC power source having a low AC impedance without floating the auxiliary electrode 26.

Here, the auxiliary electrode 26 has a display area A.
Since it is arranged around ₁ A ₂ A ₃ A ₄ , it is noticeable to the operator.
Therefore, it is desirable that the material of the auxiliary electrode 26 is the same as that of the electrodes X and Y and the extension electrode 25 so that the auxiliary electrode 26 is not visible to the operator. That is, ITO or the like is suitable for a transmissive liquid crystal panel. On the other hand, in the case of a reflective liquid crystal panel, the back electrode (segment electrode X in this embodiment) is often made of metal, and in that case, it may be made of metal.

In this way, by making the material of the auxiliary electrode 26 the same as the electrodes X and Y, the auxiliary electrode 26 is placed on the glass substrate 15 or 16 and the common electrode Y.
It can be formed simultaneously with the formation of the segment electrode X and the segment electrode X, and it is not necessary to specially provide the auxiliary electrode formation step.

At this time, the auxiliary electrode 26 is formed on the glass substrate on which the common electrode Y is formed, so that no matter what voltage is applied to the auxiliary electrode 26, the image display is not adversely affected and the liquid crystal is not electrolyzed. 15 or the glass substrate 16 on which the segment electrode X is formed may be formed. Therefore, when the glass substrates 15 and 16 are provided so as to face each other, it is necessary to keep the auxiliary electrodes 26 facing each other at the same potential.

The shape of the auxiliary electrode 26 is preferably an electrode formed by a single plate because its purpose is to shield, but it is not particularly limited to this, and both electrodes X and Y are formed. Alternatively, it may be formed in a comb shape depending on the appearance with the extension electrode 25.

<Fourth Embodiment> In the present embodiment, the third embodiment
It is intended to further reduce the cost and the size of the display panel with a pen input function in the embodiment.

In FIG. 3, the length "l" of the extension electrode 25 is preferably longer in order to improve the coordinate detection accuracy. However, since the portion of the extension electrode 25 does not contribute to image display at all, it is desirable that the extension electrode 25 be as short as possible in view of cost reduction and size reduction of the liquid crystal panel 1. However, shortening the length "l" of the extension electrodes 25, it applied to the region R ₃ where the tip position of the detection pen 8 is electrostatically coupled with the common electrode Y when located within a circle P ₃ in a fan shape electrode 17 I will end up.

Therefore, in this embodiment, as shown in FIG. 5, the fan-shaped electrode 17 is covered with the shield electrode 32 as in the case of the first embodiment. Thus, the fan-shaped electrode 1
The action of the detection pen 8 on the detection electrode 13 due to the voltage of 7 is blocked, and the length "l" of the extension electrode 31 can be reduced. That is, the detection pen 8 around the liquid crystal panel 1
Of the first embodiment in which the electrostatic coupling range between the detection electrode 13 and the common electrode Y is narrowed, and in the second and third embodiments in which the size of the liquid crystal panel 1 is increased and the cost is increased. The drawbacks are eliminated.

FIG. 6 is a sectional view of FIG. 5, and the shield electrode 32 in the case of the present embodiment also has a lower surface of the protective panel 23, an upper surface of the glass substrate 15 or the polarizing plate 22 as in the first embodiment. Is formed on the surface of the. An appropriate value of the length "l" of the extension electrode 31 in the practical range is the distance "d" between the tip of the detection pen 8 and the upper electrode (common electrode Y in this embodiment). is there. However, the value is not limited to this value, and is practically applicable within a range of 0.5d ≦ l ≦ 2.0d. Therefore, it may be set within the above range in consideration of other factors. .

At that time, as described in the first embodiment,
By applying a scanning voltage to the shield electrode 32, the "0" th and "m +"
It can also function as the 1 "-th segment electrode X.

As described above, in this embodiment, since the fan-shaped electrode 17 formed outside the extension electrode 31 is covered with the shield electrode 32, the detection pen 8 based on the voltage of the fan-shaped electrode 17 is used.
It is possible to shorten the length "l" of the extension electrode 31 by blocking the effect of the above on the detection electrode 13. Therefore, according to this embodiment,
It is possible to realize a compact and low-cost display panel with a pen input function in which the relationship between the actual y-coordinate “y” and the detected y-coordinate “y _d ” is in direct proportion.

In each of the above embodiments, as shown in FIG.
A display panel in which a printed circuit board on which a TAB film on which a liquid crystal driving LSI is mounted is fixed is attached to an electrode extraction portion of the liquid crystal panel 1 will be described. However, the present invention is not limited to this, and can be applied to a display panel in which the liquid crystal driving LSI is directly formed on the glass substrate of the liquid crystal panel 1.

Further, in each of the above embodiments, one common drive circuit 2 is provided on the side of the display area A ₁ A ₂ A ₃ A ₄ of the liquid crystal panel 1 on the side of A ₁ A ₄ while the side A ₃ A _{4 is} arranged. A display panel provided with one segment drive circuit 3 on the side is described. However, the present invention provides a display panel having a plurality of common drive circuits or a plurality of segment drive circuits on one side, and a drive circuit provided on each of two facing sides so that every other drive circuit has a drive circuit. It goes without saying that the present invention can also be applied to a display panel that drives electrodes. It can also be applied to a display panel in which the display surface of the liquid crystal panel 1 and the drive circuit are integrally formed of polysilicon.

Further, in each of the above-mentioned embodiments, the duty type liquid crystal panel is described as an example, but the present invention is not limited to this. That is, a liquid crystal panel by another driving method such as an active matrix type liquid crystal panel using a TFT (thin film transistor) or an EL (electro
It can also be applied to luminescence display panels and plasma display panels.

Here, in each of the above embodiments, the case where all the electrodes X and Y in the display area A ₁ A ₂ A ₃ A ₄ are arranged in a straight line is explained. It should be noted that the straight line in (2) includes a case where fine zigzag wiring is made in pixel units, but is linear on average, as in an active matrix liquid crystal panel.

[0093]

As is apparent from the above, the following effects can be obtained in the panel with a coordinate detection function by pen input according to the present invention. In the coordinate detection area of the panel
Where there is no first and second electrode outside
Form an auxiliary electrode and connect this auxiliary electrode to the desired voltage source.
Therefore, for example, the auxiliary electrode is grounded or connected.
By connecting to a DC power source with low current impedance
From where the first and second electrodes do not exist
From electric parts such as fluorescent backlights that are about to leak
The AC electric field can be shielded. Therefore, electrostatic
When performing pen input by the coupling method,
Induced on the sensing electrode of the sensing pen due to the alternating electric field of
Eliminate noise and erroneously detect input coordinates with the detection pen
It is possible to prevent outflow .

In addition to the above effects, the display quality is improved.
In addition, cost reduction and size and weight reduction can be achieved .

Outside the display area of the display panel
Facing each other where the first and second electrodes do not exist
The auxiliary electrode is formed so that it does not
The auxiliary electrode drive circuit
Apply a scanning voltage to the electrode to move the auxiliary electrode as if
The outermost electrode in the first and second electrode groups of the display panel
Since it is operated as if there is one,
If there is a detection pen on the
The induced distortion of the detection signal can be prevented. Shi
Therefore, the coordinate detection accuracy in the corner of the display area is improved.
It is Mel possible.

At this time, the auxiliary electrodes should not face each other.
It is shaped like Therefore, the scanning voltage is
When applied to the auxiliary electrode, the display layer of the display panel is electrically charged.
No pressure is applied to prevent adverse effects on the image display and display layer.
You can stop .

[0097]

[0098]

[0099]

[0100]

[0101]

[Brief description of drawings]

FIG. 1 is a partially enlarged view of a peripheral portion of a display area of a liquid crystal panel in an embodiment of a display panel with a pen input function of the present invention.

2 is a cross-sectional view taken along a common electrode in the liquid crystal panel shown in FIG.

FIG. 3 is a partially enlarged view of a peripheral portion of a display area in a liquid crystal panel different from that in FIG.

FIG. 4 is a partially enlarged view of a peripheral portion of a display area in a liquid crystal panel different from FIGS. 1 and 3.

5 is a partially enlarged view of a display area peripheral portion in a liquid crystal panel different from FIGS. 1, 3 and 4. FIG.

6 is a cross-sectional view taken along a common electrode in the liquid crystal panel shown in FIG.

FIG. 7 is a block diagram of a display panel with a pen input function using a duty type liquid crystal panel.

8 is a diagram showing drive timing of the display panel with a pen input function shown in FIG.

9 is an explanatory diagram of electrostatic coupling between a detection electrode of a detection pen and each electrode of the liquid crystal panel in the display panel with a pen input function shown in FIG.

10 is a diagram showing a detection signal induced in the detection electrode of the detection pen and its processed waveform when each electrode of the liquid crystal panel in the display panel with a pen input function shown in FIG. 7 is scanned.

11 is a diagram showing a connection state of electrode terminals of respective electrodes of the liquid crystal panel and a common drive circuit and a segment drive circuit in the display panel with a pen input function shown in FIG.

12 is a partially enlarged view of a peripheral portion of a display area of a liquid crystal panel in the display panel with a pen input function shown in FIG.

13 is a diagram showing the relationship between the actual y coordinate and the detected y coordinate of the tip of the detection pen in the display panel with pen input function shown in FIG.

[Explanation of symbols]

21, 32 ... Shielding electrodes, 25, 31 ... Extension electrodes, 26 ... Auxiliary electrodes.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G06F 3/03-3/033

Claims (3)

(57) [Claims] 1. A panel having a coordinate detection area in which first electrodes arranged in parallel and second electrodes arranged in parallel are arranged in a grid pattern, and the first electrode and the second electrode of the panel are electrostatically charged. A detection pen having a detection electrode to be coupled to the tip thereof, a first drive circuit including a drive integrated circuit for driving the first electrode group, and a second drive including a drive integrated circuit for driving the second electrode group Circuit, and is induced in the detection electrode of the detection pen when the first electrode group and the second electrode group are sequentially scanned based on the detection control signal by the first drive circuit and the second drive circuit. In a panel with a coordinate detection function by pen input for detecting tip coordinates of a detection pen on the panel based on a detection signal, the first electrode outside the coordinate detection area of the panel
And the second electrode is formed at the location where it does not exist,
A panel with a coordinate detection function by pen input, comprising an auxiliary electrode connected to a predetermined voltage source . Wherein said panel is a display panel, the first conductive pole group and the second conductive-polar also serves as a display electrode group of the display panel, the first drive dynamic circuit and the second drive dynamic claim 1 coordinate detection function with the panel with a pen input, wherein the composed are shared with the drive circuit of the display panel and the circuit. 3. A parallel first electrode and a parallel second electrode.
The poles are arranged in a grid patterndisplayHave an areadisplayPa
Nell and the abovedisplayStatic with the first and second electrodes of the panel
A detection pen having a detection electrode electrically coupled to the tip,
A first integrated circuit for driving the first electrode group
Driving circuit and driving integrated circuit for driving the second electrode group
And a second drive circuit consisting ofDuring the display period,
Display control signal by the first drive circuit and the second drive circuit
And controlling the first electrode group and the second electrode group based on
While displaying the image on the display panel, during the coordinate detection period
IsDetection control by the first drive circuit and the second drive circuit
The first electrode group and the second electrode group based on the control signal.
The detection induced on the detection electrode of the detection pen during the next scan
Based on the outgoing signaldisplayOf the detection pen on the panel
Panel with coordinate detection function by pen input to detect tip coordinates
In Le,The first electrode outside the display area of the display panel
And do not face each other where the second electrode does not exist
An auxiliary electrode formed as A scanning voltage is applied to the auxiliary electrode based on the detection control signal.
Is applied to the auxiliary electrode as if it were the first and second electrodes.
Auxiliary to act as if it were the outermost electrode in the pole group
Equipped with electrode drive circuit By pen input that is characterized by
Panel with coordinate detection function.