JPH0793093A - Display panel with pen input function - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the coordinate detection accuracy in the periphery of the display area. A TA corresponding to a common electrode Y or a segment electrode X outside a display area of a liquid crystal panel
The fan-shaped electrode 17 connected to the B film is covered with the shield electrode 21 to block the action of the voltage of the fan-shaped electrode 17 on the detection electrode of the detection pen. In this way, the detection signal is not induced in the detection electrode of the detection pen due to the voltage of the fan-shaped electrode 17, and when the tip of the detection pen is within the circle P ₁ , the detection electrode is electrostatically coupled to the electrodes X and Y. The coupling range is limited to the region in which the common electrodes Y arranged in parallel are present in the region R ₂ .
As a result, the relationship between the actual y coordinate of the tip of the detection pen and the detected y coordinate when scanning the common electrode Y is in direct proportion, and the coordinate detection accuracy in the peripheral portion of the display area is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display panel with a pen input function used in information equipment 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.

Therefore, an object of the present invention is to provide a display panel with a pen input function capable of improving the coordinate detection accuracy in the peripheral portion of the display area.

[0024]

In order to achieve the above object, the invention according to claim 1 has a display area in which first electrodes arranged in parallel and second electrodes arranged in parallel are arranged in a grid pattern. A display panel, a detection pen having at its tip a detection electrode that is electrostatically coupled to the first electrode and the second electrode of the display panel, and a first drive including an integrated circuit for driving the first electrode group. A second driving circuit composed of a driving circuit for driving the second electrode group, and the first driving circuit and the second driving circuit in the display period based on the display control signal. While controlling the first electrode group and the second electrode group to display an image on the display panel, during the coordinate detection period, the first electrode group is based on the detection control signal by the first drive circuit and the second drive circuit. And when the second electrode group is sequentially scanned In a display panel with a pen input function that detects the tip coordinates of the detection pen on the display panel based on a detection signal induced in the detection electrode of the detection pen, in the peripheral portion of the display panel, A shield electrode that shields electrostatic coupling between a terminal electrode that connects one end of each electrode forming the two-electrode group to the corresponding drive integrated circuit and a detection electrode of the detection pen located in the peripheral portion of the display area. The detection electrode of the detection pen is electrostatically coupled only to the first and second electrodes arranged in a grid in the display area of the display panel.

According to a second aspect of the present invention, a display panel having a display area in which first electrodes arranged in parallel and second electrodes arranged in parallel are arranged in a grid pattern, and the first electrode of the display panel. And a detection pen having a detection electrode at its tip which is electrostatically coupled to the second electrode, a first drive circuit including a drive integrated circuit for driving the first electrode group, and driving the second electrode group A second driving circuit composed of a driving integrated circuit, and controlling the first electrode group and the second electrode group based on a display control signal by the first driving circuit and the second driving circuit during a display period. While displaying an image on the display panel, during the coordinate detection period, 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. Detection induced on the detection electrode of the detection pen In a display panel with a pen input function that detects the tip coordinates of the detection pen on the display panel based on a signal, in the peripheral portion of the display panel,
The electrodes are extended by linearly extending a predetermined length in a direction in which the electrodes extend from one end of each of the electrodes forming the first and second electrode groups toward the outside of the display area. The terminal electrode, which is provided with an extension electrode and connects at least one end of each extension electrode to the corresponding driving integrated circuit, is electrostatically coupled with the detection electrode of the detection pen located in the peripheral portion of the display area of the display panel. It is characterized in that it is located in a region in which a strong bond cannot be formed.

According to a third aspect of the invention, in the display panel with a pen input function according to the second aspect of the invention, the extension electrode is made of the same material as that of the connected first electrode or second electrode. It is characterized in that it is provided with a shield electrode which is formed to have a width and shields electrostatic coupling between the detection electrode of the detection pen and the terminal electrode which is located in the peripheral portion of the display area of the display panel.

According to a fourth aspect of the present invention, in the display panel with a pen input function according to the first or third aspect of the invention, each of the shield electrodes is applied to the shield electrode based on the detection control signal during the coordinate detection period. A shield electrode drive circuit that applies a scanning voltage at a predetermined timing is provided, and during the coordinate detection period, each shield electrode is as if it were an outermost electrode in the first electrode group or the second electrode group. It is characterized by operating.

According to a fifth aspect of the present invention, in the display panel with a pen input function according to the second aspect of the invention, the auxiliary electrodes formed outside the four corners of the display area of the display panel, where the extension electrodes are not provided. An electrode and an auxiliary electrode drive circuit for applying a scanning voltage to each of the auxiliary electrodes at a predetermined timing based on the detection control signal in the coordinate detection period, and each of the auxiliary electrodes in the coordinate detection period. It is also characterized in that it is operated as if it were the outermost electrode in the first electrode group or the second electrode group.

According to a sixth aspect of the invention, in the display panel with a pen input function according to the fourth aspect of the invention, the shield electrode drive circuit applies a pulse voltage as the scanning voltage based on the detection control signal. A pulse voltage generating means for generating is provided, and the pulse voltage is applied to the shield electrode during the coordinate detection period.

According to a seventh aspect of the invention, in the display panel with a pen input function according to the fifth aspect of the invention, the auxiliary electrode drive circuit applies a pulse voltage as the scanning voltage based on the detection control signal. A pulse voltage generating means for generating is provided, and the pulse voltage is applied to the auxiliary electrode during the coordinate detection period.

The invention according to claim 8 is the display panel with a pen input function according to any one of claims 2 to 7, wherein the extension electrode or the auxiliary electrode is
It is characterized in that the same electrodes are formed so as not to face each other.

[0032]

In the invention according to claim 1, when the detection pens are located in the peripheral portion of the display panel, one ends of the first and second electrodes arranged in a grid pattern in the display area of the display panel are The electrostatic coupling between the terminal electrode connected to the corresponding driving integrated circuit and the detection electrode of the detection pen is shielded by the shield electrode. As a result, the detection electrodes of the detection pen are electrostatically coupled only to the first and second electrodes in the display area.

Thus, during the coordinate detection period, no matter where the detection pen is on the display panel, it is caused only by the scanning voltages of the first and second electrodes arranged in parallel in the display area. Then, a detection signal is induced in the detection electrode of the detection pen. Therefore, the distortion of the detection signal due to the influence of the voltage of the terminal electrodes which are not arranged in parallel is removed.

Further, in the invention according to claim 2, when the detection pens are positioned in the peripheral portion of the display panel, the first and second electrodes arranged in a grid pattern in the display area of the display panel are arranged. A terminal electrode connecting at least one end of the extension electrode, which extends each electrode by a predetermined length from one end to the outside of the display area, to a corresponding drive integrated circuit, is a detection electrode of the detection pen electrostatically. Is outside the area where a strong bond can be formed. As a result, the detection electrode of the detection pen is electrostatically coupled only to the first and second electrodes and the extension electrode.

Thus, in the coordinate detection period, even if the detection pen is at any position on the display panel,
A detection signal is induced in the detection electrodes of the detection pen only due to the scanning voltages of the first and second electrodes and the extension electrode arranged in parallel. Therefore, the distortion of the detection signal due to the influence of the voltage of the terminal electrodes which are not arranged in parallel is removed.

Further, in the invention according to claim 3, when the detection pen is positioned in the peripheral portion of the display panel, the detection electrode and the terminal electrode connecting one end of the extension electrode to the corresponding drive integrated circuit and the detection pen. The electrostatic coupling with the detection electrode is shielded by the shield electrode. Thus, during the coordinate detection period, the scanning of the first and second electrodes and the extension electrodes, which are formed of the same material and have the same width and are arranged in parallel, regardless of the position of the detection pen on the display panel. Due to only the voltage, a detection signal of the same characteristic is induced in the detection electrode of the detection pen regardless of the type of electrode.

In the invention according to claim 4, in the coordinate detection period, the shield electrode drive circuit applies the scanning voltage based on the detection control signal to each shield electrode at a predetermined timing. Thus, during the coordinate detection period, each of the shield electrodes is operated by the first electrode group or the second electrode group.
It operates as if it were the outermost electrode in the electrode group, and the distortion of the detection signal when the detection pen is positioned in the peripheral portion of the display area of the display panel is eliminated.

Further, in the invention according to claim 5, in the coordinate detection period, the auxiliary electrode drive circuit causes the scanning voltage based on the detection control signal to be applied to a portion outside the four corners in the display area of the display panel where the extension electrodes are not present. It is applied to the formed auxiliary electrode at a predetermined timing. Thus, during the coordinate detection period, the auxiliary electrodes are operated as if they were the outermost electrodes of the first electrode group or the second electrode group, and the detection pens are located at the four corners of the display area. At this time, the distortion of the detection signal is eliminated.

Further, in the invention according to claim 6, in the coordinate detection period, the pulse voltage as the scanning voltage is generated by the pulse voltage generation means in the shield electrode drive circuit based on the detection control signal. The voltage is applied to the shield electrode at the predetermined timing.

Further, in the invention according to claim 7, in the coordinate detection period, the pulse voltage as the scanning voltage is generated by the pulse voltage generation means in the auxiliary electrode drive circuit based on the detection control signal. The voltage is applied to the auxiliary electrode at the predetermined timing.

Further, in the invention according to claim 8, in the coordinate detection period, the scanning voltage is applied from the driving integrated circuit to the extension electrode or the auxiliary electrode formed so as not to face each other. Thus, the scanning voltage is applied to the first and second electrodes or the auxiliary electrode without applying a voltage to the display layer of the display panel by the extension electrode or the auxiliary electrode.

[0042]

The present invention will be described in detail below with reference to the embodiments shown in the drawings.

The present invention relates to an improvement of the display panel peripheral portion of a display panel with a pen input function, an example of which is shown in FIGS. 7, 11 and 12, and the configuration other than the display panel peripheral portion is shown in FIGS. It is exactly the same as in FIG. Therefore, in each of the following embodiments, the constituent members other than the peripheral portion of the display panel are denoted by the member numbers and the member numbers in FIGS. 7, 11, and 12, and the detailed description thereof will be 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 display panel with a pen input function of the invention according to claim 1 corresponds to one end of the first and second electrodes arranged in a grid in the display area of the display panel. Since the electrostatic coupling between the terminal electrode connected to the driving integrated circuit and the detection electrode of the detection pen located in the peripheral portion of the display area is shielded by the shield electrode, the detection electrodes of the detection pen are parallel to each other. It can be electrostatically coupled only to the arranged first and second electrodes. Therefore, when the detection pen traces the peripheral area of the display area of the display panel, the actual coordinates of the tip of the detection pen and the detected coordinates have a direct proportional relationship, and the coordinate detection accuracy in the peripheral area of the display area can be improved. .

In the display panel with a pen input function according to the second aspect of the present invention, at least one end of the first and second electrodes arranged in a grid pattern in the display area of the display panel is extended by an extension electrode. The terminal electrodes connecting one end of the extension electrode to the corresponding driving integrated circuit are formed in the peripheral portion of the display area because they extend linearly outward in the direction in which the electrodes extend. The sensing electrode of the sensing pen located at is outside the area where it can be electrostatically coupled. Therefore, the detection electrodes of the detection pen can be electrostatically coupled only to the first and second electrodes and the extension electrodes arranged in parallel. That is, according to the present invention, when the detection pen traces the peripheral area of the display area of the display panel, the real coordinates of the tip of the detection pen and the detected coordinates have a direct proportional relationship, and the coordinate detection in the peripheral area of the display area is performed. The accuracy can be increased.

At this time, since at least one ends of the first and second electrodes are extended by the extension electrodes, the detection electrodes of the detection pen located in the peripheral portion of the display area are currently scanned. The range of electrostatic coupling with is not reduced. Therefore, according to the present invention, even if the detection pen is in the peripheral portion of the display area, the output of the detection signal induced in the detection electrode of the detection pen does not decrease, and stable coordinate detection can be performed.

Further, in the display panel with a pen input function according to a third aspect of the present invention, the extension electrode is formed of the same material as the first electrode or the second electrode to which the extension electrode is connected in the same width, The electrostatic coupling between the detection electrodes of the detection pen located at the periphery of the display area of the display panel and the terminal electrodes is shielded by the shield electrode, so that the display area is reduced even if the length of the extension electrode is shortened. It is possible to improve the coordinate detection accuracy in the peripheral portion. Therefore,
According to the present invention, a display panel with a pen input function capable of accurately and stably detecting the tip coordinates of the detection pen even if the detection pen is present in the peripheral portion of the display area can be formed compactly and at low cost. .

Further, in the display panel with a pen input function of the invention according to claim 4, the scanning voltage based on the detection control signal is applied to each shield electrode at a predetermined timing by the shield electrode drive circuit during the coordinate detection period. Since each of the shield electrodes is operated as if it is the outermost electrode in the first electrode group or the second electrode group, detection of the detection pen is performed when the detection pen is in the peripheral portion of the display area of the display panel. It is possible to prevent the waveform distortion of the detection signal induced in the electrodes. Therefore, according to the present invention, the coordinate detection accuracy in the display area peripheral portion can be further improved.

Further, in the display panel with a pen input function according to a fifth aspect of the present invention, during the coordinate detection period, an auxiliary electrode is formed on an auxiliary electrode formed at a position where there are no extension electrodes outside the four corners in the display area of the display panel. A driving circuit applies a scanning voltage based on the detection control signal at a predetermined timing to cause each of the auxiliary electrodes to function as the first electrode group or the second electrode group.
Since the electrodes are operated as if they were the outermost electrodes in the electrode group, the waveform distortion of the detection signal induced in the detection electrodes of the detection pen when the detection pens are at the four corners of the display area of the display panel can be prevented. Therefore, according to the present invention, it is possible to further improve the coordinate detection accuracy at the four corners of the display area.

Further, in the display panel with a pen input function according to a sixth aspect of the present invention, the pulse voltage generated based on the detection control signal by the pulse voltage generating means of the shield electrode drive circuit during the coordinate detection period is shielded. Since the scanning voltage is applied to the electrodes, the coordinate detection accuracy in the peripheral portion of the display area can be further improved.

Further, in the display panel with a pen input function of the invention according to claim 7, the pulse voltage generated by the pulse voltage generating means of the auxiliary electrode drive circuit based on the detection control signal in the coordinate detection period is used as the auxiliary voltage. Since the scanning voltage is applied to the electrodes, the coordinate detection accuracy at the four corners of the display area can be further improved.

Further, in the display panel with a pen input function of the invention according to claim 8, since the extension electrodes or the auxiliary electrodes are formed so that the same electrodes do not face each other, the extension electrodes are formed during the coordinate detection period. Alternatively, when the scan electrode is applied to the auxiliary electrode, no voltage is applied to the display layer of the display panel. Therefore, it is possible to prevent the pixels of the display panel from being unnecessarily displayed during the coordinate detection period.

[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.

Claims (8)

[Claims] 1. A display panel having a display area in which first electrodes arranged in parallel and second electrodes arranged in parallel are arranged in a grid pattern, and the first and second electrodes of the display panel are electrostatically coupled. A detection pen having at its tip a detection electrode coupled to
A first integrated circuit for driving the first electrode group,
A second drive circuit including a drive circuit and a drive integrated circuit for driving the second electrode group is provided, and during the display period, the first drive circuit and the second drive circuit operate on the basis of a display control signal. While controlling the first electrode group and the second electrode group to display an image on the display panel, during the coordinate detection period,
The display based on the detection signal induced in the detection electrode of the detection pen when the first electrode group and the second electrode group are sequentially scanned by the first drive circuit and the second drive circuit based on the detection control signal. In a display panel with a pen input function for detecting the tip coordinates of a detection pen on the panel, in the peripheral part of the display panel, one end of each of the electrodes forming the first and second electrode groups corresponds to the driving integrated circuit. And a shield electrode for shielding electrostatic coupling between the terminal electrode connected to the display electrode and the detection electrode of the detection pen located in the peripheral portion of the display area, and the detection electrode of the detection pen is the display of the display panel. A display panel with a pen input function, which is electrostatically coupled only to the first and second electrodes arranged in a grid pattern in a region. 2. A display panel having a display region in which first electrodes arranged in parallel and second electrodes arranged in parallel are arranged in a grid pattern, and the first and second electrodes of the display panel are electrostatically coupled. A detection pen having at its tip a detection electrode coupled to
A first integrated circuit for driving the first electrode group,
A second drive circuit including a drive circuit and a drive integrated circuit for driving the second electrode group is provided, and during the display period, the first drive circuit and the second drive circuit operate on the basis of a display control signal. While controlling the first electrode group and the second electrode group to display an image on the display panel, during the coordinate detection period,
The display based on the detection signal induced in the detection electrode of the detection pen when the first electrode group and the second electrode group are sequentially scanned by the first drive circuit and the second drive circuit based on the detection control signal. In a display panel with a pen input function for detecting the tip coordinates of a detection pen on the panel, in the peripheral portion of the display panel, at least one end of each electrode forming the first and second electrode groups is located outside the display area. An extension electrode that extends linearly in the direction in which each of the electrodes extends for a predetermined length to extend each electrode, and one end of each extension electrode is connected to the corresponding drive integrated circuit. Pen input function characterized in that the terminal electrode to be connected is located in an area where electrostatic coupling with the detection electrode of the detection pen located in the peripheral portion of the display area in the display panel cannot be formed. Display panel. 3. The display panel with a pen input function according to claim 2, wherein the extension electrode is made of the same material as the connected first electrode or second electrode and has the same width, and A display panel with a pen input function, comprising a shield electrode for shielding the electrostatic coupling between the detection electrode of the detection pen and the terminal electrode, which is located in the peripheral portion of the display area of the panel. 4. The display panel with pen input function according to claim 1 or 3, wherein a scanning voltage is applied to each shield electrode at a predetermined timing based on the detection control signal during the coordinate detection period. A pen input, comprising a shield electrode drive circuit, and operating the shield electrodes as if they were the outermost electrodes in the first electrode group or the second electrode group during the coordinate detection period. Display panel with functions. 5. The display panel with a pen input function according to claim 2, wherein auxiliary electrodes formed outside the four corners of the display area of the display panel where the extension electrodes are not provided, and during the coordinate detection period, An auxiliary electrode drive circuit for applying a scanning voltage to each of the auxiliary electrodes at a predetermined timing based on the detection control signal is provided, and each of the auxiliary electrodes is operated in the first electrode group or the second electrode during the coordinate detection period. A display panel with a pen input function, which is operated as if it is the outermost electrode in an electrode group. 6. The display panel with pen input function according to claim 4, wherein the shield electrode drive circuit includes pulse voltage generation means for generating a pulse voltage as the scanning voltage based on the detection control signal. The display panel with a pen input function, wherein the pulse voltage is applied to the shield electrode during the coordinate detection period. 7. The display panel with a pen input function according to claim 5, wherein the auxiliary electrode drive circuit includes pulse voltage generation means for generating a pulse voltage as the scanning voltage based on the detection control signal. A display panel with a pen input function, wherein the pulse voltage is applied to the auxiliary electrode during the coordinate detection period. 8. The display panel with a pen input function according to claim 2, wherein the extension electrodes or the auxiliary electrodes are formed so that the same electrodes do not face each other. Display panel with pen input function.