JPH1096939A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device allowing to be stabilized in detecting a pen input position, detect a precise temperature of a liquid crystal, extend a display area 13, and narrow frame widths. SOLUTION: Spare electrodes 16 are formed outside of a display area 14 except corner areas 15 of a substrate 11, and the corner areas having no spare electrodes 16 of the substrate 11 are beveled. The spare electrodes are used as a stabilization means for detecting a pen input position and a temperature sensor for detecting a temperature of liquid crystal. In a case of housing a same size of a product, it is possible to make a display area 13 extended and a frame width narrower, compared with a case of providing the spare electrodes in circumference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device in which a liquid crystal is sandwiched between a pair of substrates having a transparent electrode formed in a display area.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal display device is used for a display of a portable information terminal, for example, because of its thinness, light weight and low power consumption. In such portable information terminals, the size of products has been reduced, but the size of the display screen in a limited size, that is, the width of the picture frame has been required, and the purpose of further improving the operability is to improve the operability. Therefore, it is required to add a pen input function and a temperature compensation function that can be used without depending on the ambient temperature.

FIGS. 6 and 7 show a conventional liquid crystal display device. A tape carrier package (hereinafter, referred to as TCP) in which a driving IC element 3 is mounted on a liquid crystal cell 2 incorporated in a product 1 such as a portable information terminal. Call) 4 vertically 1
And two in the horizontal direction. Each of these TCPs 4 is mounted on a printed circuit board 5, respectively. In the liquid crystal cell 2, the pixel electrodes 6 are arranged in the display area (a range surrounded by points a, b, c, and d) in a grid pattern in the vertical and horizontal directions.
The end of the wiring for the pixel electrodes 6 arranged in the vertical direction is connected to the TCP 4 for vertical driving via the oblique wiring part 7, and the end of the wiring for the pixel electrodes 6 arranged in the horizontal direction is connected via the oblique wiring part 7. It is connected to TCP4 for horizontal driving.

In general, a portable information terminal often employs a pen input function for the purpose of improving operability. In the liquid crystal display device having the pen input function, a sheet for input position detection is adhered to the liquid crystal cell 2, and a pen (pen electrode) is brought into contact with the sheet surface to thereby form a pixel corresponding to the contact position. The capacitance of the electrode 6 changes, and this change is read via the wiring around the pixel electrode 6 to detect the pen contact position.

However, in the liquid crystal display device having the pen input function, for example, when the pen is brought into contact with a point e near the outside of the display area shown in FIGS. The main area to be covered is around the contact point of the pen, which includes not only the display area but also the oblique wiring section 7 outside the display area. Further, when the pen is in contact with the outermost part of the display area, the detected waveform is different from that in the case where the pen is in contact with the center of the display area.
That is, there is a problem that the coordinates detected by the touch of the pen are different from the coordinates of the touch by the pen.

Accordingly, there is a method of forming a spare electrode all around the liquid crystal cell 2 outside the display area. With this spare electrode,
When the pen touches the vicinity of the outside of the display area of the liquid crystal panel 2, the electrostatic coupling between the pixel electrode 6 and the oblique wiring portion 7 with which the pen contacts is shielded. Therefore, the pen contact position can be accurately detected without being affected by the oblique wiring portion 7.

In addition, in a liquid crystal display device used under severe temperature changes such as outdoors or in a car, the optimum operating voltage of the liquid crystal changes depending on the temperature of the liquid crystal. Therefore, a temperature compensation function is employed because the luminance is reduced. In this temperature compensation function, generally, a temperature sensitive element such as a thermistor is attached to a liquid crystal display device, and the operating voltage is adjusted by detecting the ambient temperature of the liquid crystal display device with the temperature sensitive element. I have.

However, in the liquid crystal display device having the temperature compensation function, the temperature of the liquid crystal display device is detected by the heat-sensitive element, and the temperature of the liquid crystal inside the liquid crystal cell 2 is not detected. Temperature cannot be detected accurately.

Therefore, a spare electrode formed outside the display area of the liquid crystal cell 2 is used as a temperature sensor, and the temperature sensor can accurately detect the temperature of the liquid crystal.

[0010]

However, when a pen input function or a temperature compensation function is added to a conventional liquid crystal display device, a spare electrode is formed on the entire periphery outside the display area, so that a product 1 having the same outer shape is used. On the other hand, when the liquid crystal cell 2 having the spare electrode and the liquid crystal cell 2 having no spare electrode are incorporated, since the outer shape of the liquid crystal cell 2 incorporated in the product 1 is the same, the liquid crystal cell 2 having the spare electrode is provided.
However, there is a problem that the display area is reduced by the size of the spare electrode, and it is difficult to narrow the frame.

The present invention has been made in view of such a point, and a spare electrode is provided outside a display area to enable stable detection of a pen input position and accurate temperature detection of a liquid crystal. It is an object of the present invention to provide a liquid crystal display device in which a display area can be made larger and a frame can be made narrower than when a spare electrode is provided on the entire periphery outside the display area when the product is stored in a product.

[0012]

According to the present invention, there is provided a liquid crystal display device in which a liquid crystal is sandwiched between a pair of substrates each having a transparent electrode formed in a display area. A spare electrode is formed outside the display area except for the corner, and a corner of the substrate having no spare electrode is chamfered.

The spare electrode is used as a stabilizing means for detecting the input position of the pen or as a temperature detection sensor of the temperature compensation circuit, whereby the detection of the input position of the pen can be stabilized and the temperature of the liquid crystal can be accurately detected. In the case where the spare electrode is formed outside the display area excluding at least one corner area of the substrate and the corner of the substrate having no spare electrode is chamfered to be housed in a product of the same size, The display area is larger and the frame is narrower than when the spare electrode is provided all around the display area. Note that the chamfer formation of the substrate includes a linear shape or an arc shape.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the liquid crystal display device of the present invention will be described below with reference to the drawings.

FIGS. 1 to 4 show a first embodiment. The same components as those of the conventional liquid crystal display device shown in FIGS. 6 and 7 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 3 is a front view of the liquid crystal display device. For example, a tape carrier package (hereinafter referred to as TCP) in which a driving IC element 3 is mounted on a liquid crystal cell 2 incorporated in a product 1 such as a portable information terminal. 4) one in the vertical direction,
Two are connected in the horizontal direction. These TCPs 4 are mounted on the printed circuit board 5 respectively.

The liquid crystal cell 2 includes, as substrates, an array substrate 11 on which pixel electrodes 6 as transparent electrodes described later are formed,
It has a counter substrate on which a counter electrode as a transparent electrode is formed, and the array substrate 11 and the counter substrate are opposed to each other, and a liquid crystal is sandwiched therebetween.

The four corners of the product 1 are formed in an arc shape, and the lower right corner of the liquid crystal cell 2 and the corners of each printed circuit board 5 corresponding to the arc-shaped corners are formed in an arc shape. Have been.

FIG. 1 is a front view of a part of the array substrate 11 of the liquid crystal display device, and FIG. 2 is an enlarged front view of a part of the array substrate 11 of the liquid crystal display device. Array substrate 11 is glass substrate 12
In the display area 13 on the glass substrate 12, the pixel electrodes 6 are formed in a grid pattern in the vertical and horizontal directions,
Furthermore, the product 1 outside the display area 14 around the display area 13
A spare electrode 16 that does not contribute to display is formed adjacent to the pixel electrode 6 at a location other than one corner region 15 at the lower right of the glass substrate 12 disposed at the corner.

A wiring portion 17 is formed adjacent to the pixel electrode 6 and the spare electrode 16.
And MI as a switching element for each spare electrode 16
A nonlinear resistance element (hereinafter, referred to as an MIM element) 18 such as M (Metal Insulator Metal) is formed. MI
The M element 18 includes a non-linear resistance film (not shown) formed so as to overlap the wiring portion 17 as one electrode, and the other electrode 19 formed so as to partially overlap the non-linear resistance film. The pixel electrode 6 is formed so as to partially overlap the other electrode 19.

The array substrate 11 can be manufactured by the same method as a general array substrate manufacturing process. That is, the spare electrode 16 can be formed outside the display region 14 in parallel with the same material and the same process for forming the pixel electrode 6 in the display region 13 on the glass substrate 12. For example, in the manufacturing process of the array substrate 11, PEP (Ph
By changing the mask pattern of the photomask used in the (oto Engraving Procss) step, the spare electrode 16 can be formed outside the display area 14 of the glass substrate 12. Such a method of changing the mask pattern can be manufactured most simply and effectively.

One corner at the lower right of the glass substrate 12 is chamfered in a shape along the edges of the pixel electrode 6 and the spare electrode 16 facing the corner region 15. The shape of the chamfer may be, for example, a straight line at 45 ° or an arc shape.

A diagonal wiring portion (not shown) is formed outside the display area 14 on the left side of the liquid crystal cell 2 to connect the ends of the wiring for the pixel electrodes 6 and the spare electrodes 16 arranged in the vertical direction to the TCP 4 for driving in the vertical direction. The pixel electrode 6 and the spare electrode arranged in the horizontal direction are arranged outside the display area 14 above the liquid crystal cell 2.
A diagonal wiring portion (not shown) for connecting the end of the wiring for 16 to the TCP 4 for horizontal driving is formed. A spare electrode 16 is interposed between the oblique wiring portion and the pixel electrode 6 in the display area 13.

Then, a temperature compensation function or a pen input function is added to the liquid crystal display device configured as described above.

First, the case where the temperature compensation function is added will be described. FIG. 4 shows a block diagram of the temperature compensating circuit 21, in which the spare electrode 16 is used as a temperature detecting sensor. The temperature of the liquid crystal is detected by the characteristic detection circuit 22 including the spare electrode 16, and the control circuit 23
Controls the driving circuit 24, and the driving circuit 24 controls the liquid crystal display device.
Adjust so that the operating voltage applied to 25 is optimal.
As described above, by using the spare electrode 16 located inside the liquid crystal cell 2 as a temperature sensor, the temperature of the liquid crystal inside the liquid crystal cell 2 can be accurately detected without being affected by changes in the ambient temperature.

On the other hand, a case where a pen input function is added will be described. Liquid crystal cell 2
By sticking a pen (pen electrode) on the sheet surface, the capacitance of the pixel electrode 6 corresponding to the contact position changes, and this change is read through the wiring around the pixel electrode 6, The pen contact position is configured to be detected. At this time, when the pen contacts the vicinity of the outside of the display area 13 of the liquid crystal panel 2, the pixel electrode 6 with which the pen contacts and the TC
Since the spare electrode 16 is interposed between the oblique wiring portion connected to P4 and the electrostatic coupling thereof is shielded by the spare electrode 16, the pen contact position can be accurately determined without being affected by the oblique wiring portion. Can be detected. Therefore, the spare electrode 16 can be used as a stabilizing means for detecting the pen input position.

In the liquid crystal cell 2, a spare electrode 16 is formed outside the display area 14 except for one corner area 15 at the lower right of the glass substrate 12 disposed at the corner of the product 1. 2
Of the pixel electrode 6 and the spare electrode 16 facing the corner region 15 are chamfered at one corner at the lower right of the pixel. The display area 13 can be made larger and the frame can be made narrower than in the case of providing.

That is, FIG. 3 shows the liquid crystal display device of the present embodiment, while FIG. 8 shows a liquid crystal cell in which spare electrodes 16 are provided all around the outside of the display area 14 for the product 1 having the same outer shape. 2
A liquid crystal display device in which is incorporated is shown, and these are compared. In the liquid crystal display device shown in FIG. 8, a spare electrode 16 is also formed at the lower right corner of the liquid crystal cell 2, and the lower right corner of the liquid crystal cell 2 is disposed inside the arc-shaped corner of the product 1. Therefore, the width L2 between the lower edge and the right edge of the liquid crystal cell 2 and the product 1 is widened, whereby the vertical dimension Y2 and the horizontal dimension X2 of the liquid crystal cell 2 are narrowed, and the display area 13 is narrowed. On the other hand, in the liquid crystal display device of the present embodiment shown in FIG. 3, the lower right corner of the liquid crystal cell 2 is chamfered without forming the spare electrode 16 and the lower right surface of the liquid crystal cell 2 is formed. Since the cut portion is disposed inside the arc-shaped corner of the product 1, the width L1 between the lower edge and the right edge of the liquid crystal cell 2 and the product 1 can be reduced.
As a result, the vertical dimension Y1 and the horizontal dimension X1 of the liquid crystal cell 2 can be widened, and the display area 13 can be widened. Moreover, since the corners of the printed circuit board 5 are also formed in an arc shape, the vertical dimension Y1 and the horizontal dimension X
1 can be wider.

As described above, the spare electrode 16 is provided outside the display area 14 so that the detection of the pen input position can be stabilized and the temperature of the liquid crystal can be accurately detected. As compared with the case where the spare electrode 16 is provided on the entire circumference of the outside 14, the display area 13 is large, and the frame can be narrowed.

FIG. 5 is a front view of the liquid crystal display device according to the second embodiment.

In this embodiment, a liquid crystal display device using a TCP 31 which is bent and mounted is provided, and three corners of the liquid crystal cell 2 at the lower right, upper right, and lower left are arranged inside the corners of the product 1. You. In the three corners of the liquid crystal cell 2, the spare electrode is located outside the display area except for the three corner areas 15.
16 are formed, and three corners of the liquid crystal cell 2 are chamfered into shapes along the edges of the pixel electrode 6 and the spare electrode 16 facing the corner region 15.

Also in the case of this embodiment, the liquid crystal display device in which the liquid crystal cell 2 provided with the spare electrode 16 on the entire periphery of the outside of the display area 14 is incorporated in the product 1 having the same outer shape as shown in FIG. In comparison, similarly to the first embodiment, the display area 13 can be large and the frame can be narrowed.

That is, in the liquid crystal display device of the present embodiment shown in FIG. 5, the three corners of the liquid crystal cell 2 are chamfered without forming the spare electrode 16, and the three chamfers of the liquid crystal cell 2 are formed. Since the portion is disposed inside the arc-shaped corner of the product 1, the width L1 between the lower edge and the right edge of the liquid crystal cell 2 and the product 1 can be reduced, whereby the vertical dimension Y1 and the horizontal The dimension X1 can be widened and the display area 13 can be widened.

The spare electrodes 16 may be formed in one row outside the pixel electrode 6 or in a plurality of rows.
In addition, the size and shape of the spare electrode 16 are
Even if they are the same or different, the same operation and effect can be obtained.

Also, a simple matrix type liquid crystal display device,
In a thin film transistor (TFT) type liquid crystal display device, the same operation and effect can be obtained by applying the spare electrode 16 as in the present embodiment.

[0036]

According to the liquid crystal display device of the present invention, a spare electrode is formed outside the display area excluding at least one corner area of the substrate, and the corner of the substrate having no spare electrode is chamfered. As a result, the stabilization of pen input position detection and accurate liquid crystal temperature detection are enabled by the spare electrode, and compared to the case where the spare electrode is provided on the entire circumference outside the display area when storing in the same size product. To increase the display area,
The frame can be narrowed.

[Brief description of the drawings]

FIG. 1 is a front view of a part of an array substrate of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is an enlarged front view of a part of an array substrate of the liquid crystal display device.

FIG. 3 is a front view of the liquid crystal display device.

FIG. 4 is a block diagram of a temperature compensation circuit according to the first embodiment;

FIG. 5 is a front view of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 6 is a front view of a conventional liquid crystal display device.

FIG. 7 is an enlarged front view of a part of a conventional liquid crystal display device.

FIG. 8 is a front view of the liquid crystal display device compared with the liquid crystal display device of FIG. 3;

FIG. 9 is a front view of the liquid crystal display device compared with the liquid crystal display device of FIG. 5;

[Explanation of symbols]

 6 Pixel electrode as transparent electrode 11 Array substrate as substrate 16 Spare electrode

Claims (3)

[Claims] 1. A liquid crystal display device in which a liquid crystal is sandwiched between a pair of substrates having a transparent electrode formed in a display region, wherein a spare electrode is formed outside a display region excluding at least one corner region of the substrate. A liquid crystal display device, wherein a corner of a substrate having no spare electrode is chamfered. 2. The liquid crystal display device according to claim 1, wherein the spare electrode is a stabilizing means for detecting a pen input position. 3. The liquid crystal display device according to claim 1, wherein the spare electrode is a temperature detection sensor of a temperature compensation circuit.