JP2003330037A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a liquid crystal display excellent in image quality by sufficiently reducing line crawling while making use of the features of a multi- scanning line system. <P>SOLUTION: One color pixel 1 of the liquid crystal display includes three pieces of dots enclosed by adjacent signal lines 2 and adjacent scanning lines 3A, 3B, 3C, and a switching element 5 and dot electrodes 6A, 6B, 6C are arranged in each dot. In each color pixel 1, three pieces of display electrodes 8A, 8B, 8C electrically connected to the dot electrodes 6A, 6B, 6C via contact holes 7 are arranged. Then, each of the display electrodes 8A, 8B, 8C is placed over three dot electrodes 6A, 6B, 6C and also one dot electrode is electrically connected to only one display electrode. The switching elements 5 and the display electrodes 8R, 8G, 8B are arranged so as not to two-dimensionally overlap each other. <P>COPYRIGHT: (C)2004,JPO

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, and more particularly to an active matrix drive type liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal display device of an active matrix driving system (Liquid Crystal Display, hereinafter referred to as LCD)
Abbreviated as "), a large number of color pixels that display one color by combining a plurality of basic colors are arranged in a matrix. Then, the large number of color pixels are matrix-driven by the large number of scanning lines (gate buses) and the large number of signal lines (source buses).

In this type of LCD, a plurality of basic colors such as R (red), G (green), and B are arranged along each signal line direction.
A panel in which a combination of three primary colors (blue) is repeatedly arranged and the number of scanning lines is the number obtained by multiplying the number of pixels in the direction along one signal line by the number of basic colors (the number of basic colors is generally 3). The configuration in that case will be described below as a “triple scanning line method”.
3) interlace drive (3)
A technique has been proposed for performing interlaced scanning in which only one line is scanned for each line. In this triple scan line system, the number of gate drivers is tripled as compared with the conventional general configuration, but the number of source drivers, which consume more power and are more expensive than the gate drivers, is 1/3. It is possible to reduce the power consumption and the cost of the LCD as a whole. Also,
By adopting the 3: 1 interlaced drive, the frame frequency (the frequency for rewriting the entire screen) becomes 1/3, so that the effect of reducing power consumption can be expected. Since the frame frequency is reduced to 1/3 of the normal frequency by performing the 3: 1 interlace drive, the smoothness of motion may be slightly lacking in displaying a moving image. However, if the application is a mobile terminal or the like that does not require smooth movement, there is no problem.

However, when the interlaced drive is adopted, there is a problem that display unevenness called line crawling is easily recognized. As a measure against line crawling, paying attention to the polarity of the signal written in each dot, the closest ones of each dot of the same basic color (for example, G among R, G, and B) driven by the drive voltage of the same polarity It has been conventionally known that it is preferable to reduce the distance D between a plurality of lines obtained when tied. Especially when the viewing distance is 30 cm, the line interval D is 260
It is known that the thickness of μm or less is desirable. According to this basic concept, the effect of reducing line crawling can be obtained by using the dot inversion drive.

[0005]

By the way, as the polarity inversion driving method for LCD, there are a dot inversion method in which image quality is emphasized and a common inversion method in which power saving is emphasized. The above-described triple scan line method and interlace drive method are considered to be suitable for applications such as mobile terminals in which power saving and low cost are more emphasized, with less emphasis on moving image display performance. . Therefore, as the polarity inversion method in this type of application, it is desirable to use the common inversion method that is more power-saving than the dot inversion method that consumes a large amount of power.

However, when 3: 1 interlace drive is performed in the conventional triple scan line configuration, if common inversion drive is adopted, the dot closest to each dot of the same basic color driven by the drive voltage of the same polarity. The interval D between the plurality of lines obtained when the two are connected to each other is as large as 6P (P: the pitch of color pixels formed of 3 dots).

FIG. 15 is a diagram for explaining this.
30 shows 30 rows of dots arranged in a matrix. “A”, “B”, and “C” on the left side of the figure are 3: 1
The write timing of interlace drive is shown. For example, first, the row indicated by "A" is sequentially written from top to bottom, then the row indicated by "B" is sequentially written from top to bottom, and finally, The rows indicated by "C" are sequentially written from top to bottom. It should be noted that "A", "B", and "C" are not regularly arranged, because R, G, and B are regularly arranged in the vertical direction, so that only the same color is always present at the timing of "A". This is to prevent writing. Further, in the case of the common inversion drive, all the dots lined up in the horizontal direction of each row have the same polarity. In FIG. 15, the first line from the top line,
Assuming that the basic colors are repeatedly arranged in the order of R, G, B, ... In the order of the second line, the third line, ..., The fifth line of the G of “-” polarity written at the timing of “A”. The dot becomes a dot, and the G dot of the next "-" polarity appears on the 23rd line. Therefore, the line interval D is 18 dots, that is, 6 pixels.

A specific example of the color pixel pitch P is 200 ppi (Pixel pe) which is generally called high definition.
The pixel density of (r Inch) is 127 μm, and the line interval D is D = 6P = 762 μm. The line spacing D is large enough to visually recognize the line crawling. For example, 3.5-inch QVGA (320 x 240 pixels), which is the mainstream of current mobile terminals
Display, P = 223.5 μm, D = 6
Since P = 1341 μm, it cannot be ignored. On the contrary, in order to suppress the line interval D to 260 μm or less, the color pixel pitch P must be 43 μm or less, and it is difficult to manufacture a display with such a high pixel density at this point, and it is not practical. That is, when the common inversion drive is adopted in the conventional triple scan line system, it is difficult to take sufficient measures against line crawling.

When dot inversion driving, which has a great effect of reducing line crawling, is employed, unlike in the case of common inversion driving, adjacent dots arranged in the horizontal direction in each row have opposite polarities, as shown in FIG. In this case, the line spacing D is D = 1.9P. 200 ppi (P
= 127 μm) pixel density, D = 241.3 μ
m, which is less than 260 μm, is a desirable line crawling countermeasure. On the other hand, when the dot inversion drive is adopted, the signal amplitude is approximately doubled as compared with the common inversion drive, so the power consumption increases, and when compared with the source driver alone, the power consumption increases to about four times. , Has the drawback.

The present invention has been made in order to solve the above-mentioned problems, and a liquid crystal display device having an excellent image quality can be obtained by sufficiently reducing the line crawling while making the most of the characteristics of the multiple scanning line system. The purpose is to Further, it is another object of the present invention to obtain a liquid crystal display device capable of achieving power saving after achieving the above object.

[0011]

In order to achieve the above object, the first liquid crystal display device of the present invention has a pair of substrates facing each other in which liquid crystal is sandwiched, and the liquid crystal is sandwiched between the pair of substrates. On one substrate, a plurality of signal lines and a plurality of scanning lines are provided in a matrix, and a plurality of pixels having different basic colors are provided, and one pixel is adjacent to a signal line adjacent to each other. A scanning element that includes dots for the number of basic colors surrounded by the scanning line, and within each dot, a switching element electrically connected to each scanning line and each signal line,
A first electrode electrically connected to the switching element is provided, and the first electrode is formed in each pixel on an insulating layer covering the first electrode, and the first electrode is formed through a contact hole penetrating the insulating layer. Second electrodes for the number of the basic colors electrically connected to one electrode are provided, each second electrode is arranged over the first electrodes for the number of the basic colors, and one second electrode is the basic electrode. Only one of the first electrodes corresponding to the number of colors is electrically connected, one first electrode is electrically connected to only one second electrode, and the switching element and the second electrode are electrically connected. Are arranged so that they do not overlap in a plane.

In the liquid crystal display device of the present invention, the first electrode is electrically connected to each signal line through the switching element, and the first electrode and the second electrode above the first electrode are connected to each signal line through the contact hole. Because it is electrically connected to the wire,
The image signal is transmitted from the first electrode to the second via the contact hole.
The configuration is such that the liquid crystal is written in the electrode and the liquid crystal is driven by the second electrode. That is, it is the second electrode that directly contributes to the display by driving the liquid crystal. In this configuration, the second electrode has a basic color number (for example, when the basic color is three colors,
Since three (three) first electrodes are arranged, the second electrode to which the image signals are simultaneously written can be arbitrarily selected on the same scanning line by appropriately selecting the formation position of the contact hole. Therefore, it is possible to arbitrarily select the basic color to be written simultaneously when the interlace driving is performed. In other words, the timing of writing a signal to each dot and the planar arrangement of the displayed basic colors can be independently determined. As a result, it is possible to implement effective line crawling countermeasures without making the array of basic colors a complicated array such as a mosaic array. When performing non-interlaced (progressive) driving without worrying about line crawling, if the basic colors of the second electrodes to which signals are simultaneously written in the same scanning line are all the same, images such as image complement and edge enhancement can be obtained. It is possible to obtain the effect of facilitating the processing.

By the way, the inventor of the present invention has already applied for an invention of the liquid crystal display device having the above structure. However, by simply adopting the above-described basic configuration, among the plurality of second electrodes, the second electrode and the switching element overlap each other in a plane, and there are portions where the switching element is present below the second electrode and where the switching element is not present. May exist. In that case, since the parasitic capacitance formed by the second electrode and the switching element becomes nonuniform between them, the offset voltage varies among the plurality of second electrodes. Here, the dielectric constant of the interlayer insulating film between the second electrode and the switching element is reduced,
The parasitic capacitance itself can be reduced by increasing the film thickness to suppress the absolute value of the parasitic capacitance variation, or the holding capacitance can be increased to keep the absolute value of the parasitic capacitance variation within the allowable range. If it can be designed so that it can be accommodated, the variation in the offset voltage is not a serious problem. However, if the pixel density is to be increased, it is difficult to satisfy the above design conditions, and in some cases, flicker or burn-in may occur.

Therefore, in the first liquid crystal display device of the present invention, since the switching element and the second electrode are arranged so as not to overlap with each other in plan view, the parasitic formed by the second electrode and the switching element. The capacitance can be reduced, and the variation in offset voltage between the plurality of second electrodes can be reduced. As a result, display defects such as flicker and burn-in can be improved while ensuring the degree of freedom in design. Specific examples of the liquid crystal display device of the already filed application and the liquid crystal display device of the present invention will be described in the [Embodiment of the Invention] section.

In a second liquid crystal display device of the present invention, liquid crystal is sandwiched between a pair of substrates which are arranged to face each other, and a plurality of signal lines and a plurality of scanning lines are provided on one of the pair of substrates. Are provided in a matrix form, and a plurality of pixels having different basic colors are provided. One pixel is a dot for the number of basic colors surrounded by adjacent signal lines and adjacent scanning lines. A switching element electrically connected to each scanning line and each signal line in each dot, and a first electrically connected to the switching element.
An electrode is provided, is formed on an insulating layer that covers the first electrode in each pixel, and is electrically connected to the first electrode through a contact hole that penetrates the insulating layer. Several second electrodes are provided, and each second electrode is arranged over the first electrodes corresponding to the number of basic colors,
The one second electrode is electrically connected to only one of the first electrodes for the number of basic colors, and the one first electrode is electrically connected to only one second electrode, In each pixel, at least one of the plurality of switching elements and any one of the plurality of second electrodes are arranged so as to overlap each other in a plane, and the number of the switching elements overlapping each second electrode. Are equal over all second electrodes.

The second liquid crystal display device of the present invention differs from the first liquid crystal display device of the present invention in that each pixel includes one of a plurality of switching elements and one of a plurality of second electrodes. Are overlapped in a plane. However, since the number of switching elements that overlap with each second electrode is equal over all the second electrodes, variations in parasitic capacitance formed by the second electrodes and switching elements can be suppressed, and variations in offset voltage can also be suppressed. .
As a result, it is possible to obtain the same effect as that of the first liquid crystal display device of the present invention in that display defects such as flicker and burn-in can be improved while ensuring the degree of freedom in design.

Further, in the first liquid crystal display device of the present invention,
Since it is necessary to arrange the switching element and the second electrode so as not to overlap with each other, the distance between the adjacent second electrodes is different between the place where the switching element is provided and the place where the switching element is not provided, and there is a wide space and a narrow space depending on colors. Therefore, when a front light is arranged on the upper surface of the liquid crystal display device, for example, moire fringes are generated due to interference with the stripes of the light guide plate, and the appearance becomes poor. Further, since the location where the switching element is arranged cannot contribute to the display, there is a problem that the area (aperture ratio) that can contribute to the display becomes small and the image becomes dark. On the other hand, in the second liquid crystal display device of the present invention, the switching element and the second
Since the electrodes and the electrodes overlap each other, the gap between the second electrodes, which cannot contribute to the display, can be narrowed with a uniform width.
A good-looking and bright image can be displayed.

Further, it is desirable that the signal lines in the second liquid crystal display device of the present invention take, for example, the following three forms. In each dot, a signal branch line that branches from the signal line and extends to the end of the dot in the extending direction of the scanning line is provided, and the switching element provided in the dot is electrically connected to the signal branch line. It can be configured to be connected. With this configuration, the area of the overlapping portion of each second electrode and the signal branch line becomes substantially equal over all the second electrodes, so that the variation in parasitic capacitance can be further suppressed and the display quality can be further improved. it can.

Alternatively, in each pixel, a signal branch line extending stepwise over a plurality of dots in the pixel is provided, and the plurality of switching elements provided in the pixel are electrically connected to the signal branch line. Can be Even with this configuration, as in the above, the area of the overlapping portion of each second electrode and the signal branch line becomes substantially equal over all the second electrodes, so that the variation in parasitic capacitance can be further suppressed and the display quality can be further improved. Can be improved.
Further, in the case of this configuration, since the area of the overlapping portion of each second electrode and the signal branch line can be made smaller than that of the above configuration by forming one signal branch line in a stepwise shape, the absolute value of the parasitic capacitance can be further reduced. Can be made smaller.

Alternatively, signal lines corresponding to the number of basic colors corresponding to dots corresponding to the number of basic colors constituting one pixel are provided in parallel with each other, and the end portions of the signal lines corresponding to the number of basic colors are electrically connected. It can be configured to. In other words, the present configuration can be said to be one in which the signal line corresponding to one pixel is branched at the root for the number of basic colors. According to this configuration, not only the parasitic capacitance generated in the switching element or the signal branch line but also the parasitic capacitance generated in all the second electrodes including the parasitic capacitance generated between the main line of the signal line and the second electrode is made uniform. Therefore, the variation of the parasitic capacitance can be minimized among these three signal line configurations.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. The liquid crystal display device of this embodiment is an active matrix liquid crystal display device, and liquid crystal is sandwiched between an active matrix substrate and a counter substrate which are arranged to face each other. A plurality of signal lines and a plurality of scanning lines are provided in a grid on the active matrix substrate, and
A large number of color pixels composed of three basic colors of R, G, and B are provided in a matrix.

FIG. 1 and FIG. 2 show a schematic structure of only 2 rows × 3 columns of a large number of color pixels forming the active matrix substrate. In the present embodiment, the electrodes have a two-story structure, FIG. 2 is a plan view showing only lower dot electrodes, which will be described later, and FIG. 1 is a plan view showing display electrodes above the dot electrodes in an overlapping manner. ,.
As shown in FIG. 2, one color pixel 1 forming the active matrix substrate has three dots 4A, 4B, which are surrounded by adjacent signal lines 2 and adjacent scanning lines 3A, 3B, 3C. It is composed of 4C. Then, within each dot 4A, 4B, 4C, each scanning line 3A,
A switching element 5 such as a TFT electrically connected to the scanning lines 3A, 3B, 3C and the signal line 2 is provided in the vicinity of an intersection of 3B and 3C and each signal line 2, and the switching element 5 is electrically connected. Connected horizontally long rectangular dot electrodes 6A, 6B, 6C (first electrodes) are provided.

Further, an insulating layer (not shown) is provided to cover the dot electrodes 6A, 6B, 6C, and as shown in FIG. 1, the dots are formed in each color pixel 1 through a contact hole 7 penetrating the insulating layer. Three vertically elongated rectangular display electrodes 8R, 8G, 8B electrically connected to the electrodes 6A, 6B, 6C
The (second electrode) is provided on the insulating layer. Each display electrode 8R, 8G, 8B extends in a direction intersecting with the dot electrodes 6A, 6B, 6C, and three dot electrodes 6A, 6B, 6
It is located over C. Display electrodes 8R, 8G, 8
B is the dot electrodes 6A, 6 through the contact hole 7
Although electrically connected to B and 6C, one display electrode is electrically connected to only one of the three dot electrodes, and one dot electrode is one. It is electrically connected only to the display electrode.

Further, in the case of the present embodiment, the switching element 5 and the display electrodes 8R, 8G, 8B are arranged at positions where they do not overlap each other in plan view. Therefore, although the upper part of the switching element 5 is covered with the insulating layer, the display electrodes 8R, 8
G and 8B do not exist.

Further, colored layers (not shown) of R, G, B of the color filter are provided corresponding to the respective display electrodes 8R, 8G, 8B. For example, the display electrode on the left side of each color pixel 1 is provided. 8R corresponds to the color R, the central display electrode 8G corresponds to the color G, and the right display electrode 8B corresponds to the color B. This array is regular over the plurality of color pixels 1, and the array of the entire color filter is a so-called vertical stripe.

On the other hand, the arrangement of the contact holes 7 differs among the color pixels 1, that is, which dot electrode is connected to which display electrode in each color pixel 1 differs among the color pixels 1. In the case of the present embodiment, in the left side color pixel 1 in the first row, the upper dot electrode 6A is connected to the left display electrode 8R, the central dot electrode 6B is connected to the central display electrode 8G, and the lower side The dot electrode 6C is connected to the right display electrode 8B.
On the other hand, in the central color pixel 1 in the first row, the upper dot electrode 6A is connected to the central display electrode 8G, the central dot electrode 6B is connected to the right display electrode 8B,
The lower dot electrode 6C is connected to the left display electrode 8R. Further, in the right side color pixel 1 in the first row, the upper side dot electrode 6A is connected to the right side display electrode 8B,
The central dot electrode 6B is connected to the left display electrode 8R, and the lower dot electrode 6C is connected to the central display electrode 8G. The arrangement of the contact holes 7 of the color pixels 1 (not shown) arranged further in the horizontal direction in the first row is this 3
It is a repeating pattern of individual color pixels. Also, 2
The arrangement of contact holes in each color pixel in the row is the same as that in the first row. That is, the same pattern is repeated when the color pixels are viewed in the vertical direction.

As can be seen from the above, the display electrodes 8R, 8G, 8B in which the image signals are simultaneously written in the same scanning lines 3A, 3B, 3C, and the display electrodes thereof, are selected depending on the position of the contact hole 7. 8R, 8
Colors R, G, B corresponding to G, 8B can be arbitrarily selected.
That is, in the example of FIG. 1, the color in which the image signal is written by the uppermost scanning line 3A is R in the left color pixel 1, G in the central color pixel 1, and B in the right color pixel 1. Therefore, the ratios of the basic colors of the display electrodes electrically connected to the same scanning line are substantially equal.

In the liquid crystal display device of the present embodiment having the above-mentioned structure, the units for three pixels shown in FIG. 1 are arranged as they are, and the timing at which the image signal is written to each display electrode 8R, 8G, 8B and each display electrode 8R, FIG. 3 schematically shows the polarities of the image signals written in 8G and 8B.
When 3: 1 interlaced common inversion driving is performed with the arrangement of the contact holes 7, a plurality of lines obtained by connecting the dots closest to the dots of the same basic color driven by the driving voltage of the same polarity , The distance D is D = 1.
7P (P: Pitch of color pixel composed of 3 dots)
Becomes In addition, in FIG. 3, a line is drawn focusing on the G dot of “+” polarity which is written at the timing of “A”.

As described above, in the case of the present embodiment, D = 6P (see FIG. 15) of common inversion driving in the prior art, and D = 1.9P (see FIG. 14) of dot inversion driving in the prior art. Compared with, the line crawling can be made less visible. For example, P = 127
At μm (200 ppi), D = 216 μm and D becomes 2
A desirable state of 60 μm or less can be achieved. On the other hand, P = 153 μm is sufficient to obtain D = 260 μm,
This level is sufficiently practical. Then, by adopting the common inversion drive, power saving of the liquid crystal display device can be achieved.

By the way, the present inventor has already applied for a liquid crystal display device having the structure shown in FIGS. FIG. 13 is a plan view showing only the lower dot electrodes 6A, 6B, 6C,
FIG. 12 is a plan view showing the display electrodes 8R, 8G, 8B above the dot electrodes 6A, 6B, 6C in an overlapping manner, and the same reference numerals are given to the same components as those in FIGS. Is omitted. In the case of the liquid crystal display device shown in FIGS. 12 and 13, the switching element 5 and a part of the display electrodes overlap each other in plan view, and particularly, all the display electrodes 8R corresponding to R (red) overlap with the switching element 5. On the other hand, G
All display electrodes 8G and 8B corresponding to (green) and B (blue)
Does not overlap with the switching element 5. In such a configuration, since the values of the parasitic capacitances formed by the display electrodes 8R, 8G, and 8B and the switching element 5 are not uniform between the display electrodes 8R and the display electrodes 8G and 8B, the offset voltage varies, In some cases, display problems such as flicker and burn-in occur.

On the other hand, in the liquid crystal display device of the present embodiment, as shown in FIG. 1, the switching element 5 and the display electrodes 8R, 8G and 8B are arranged so as not to overlap in a plane. Therefore, the parasitic capacitance formed by the switching element 5 and the display electrodes 8R, 8G, 8B becomes sufficiently small, and the variation in the offset voltage among the plurality of display electrodes 8R, 8G, 8B can be reduced. As a result, it is possible to eliminate display problems such as flicker and burn-in while ensuring the degree of freedom in design.

[Second Embodiment] The second embodiment of the present invention will be described below.
An embodiment will be described with reference to FIGS. 4 and 5. The basic configuration of the liquid crystal display device of this embodiment is almost the same as that of the first embodiment, FIG. 5 is a plan view showing only the dot electrodes 6A, 6B, 6C of the liquid crystal display device of this embodiment, and FIG. Further, the display electrodes 8R above the dot electrodes 6A, 6B and 6C,
It is a top view which overlaps 8G and 8B. 4 and 5, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the liquid crystal display device of the first embodiment, all the switching elements 5 are arranged in which display electrodes 8R, 8G,
The liquid crystal display device according to the present embodiment has three switching elements 5A and 5B in one color pixel 1 as shown in FIGS. , 5C overlap with the three display electrodes 8R, 8G, 8B in the color pixel 1 in plan view. Further, in one color pixel 1, for example, 2
The three switching elements 5A, 5B and 5C do not overlap the same display electrode, and the three switching elements 5A, 5B and 5C respectively overlap the different display electrodes 8R, 8G and 8B. That is, each display electrode 8R, 8G, 8B overlaps with one switching element 5A, 5B, 5C,
The number of switching elements 5A, 5B, 5C overlapping with the respective display electrodes 8R, 8G, 8B is equal to that of all the display electrodes 8R, 8G, 8
It is equal over B.

As for the structure of the lower layer side, as shown in FIG. 5, the switching element 5A is arranged to the left of the dot in the upper dot 4A in one color pixel 1, and the switching is performed in the center of the dot in the central dot 4B. The element 5B is arranged, and in the lower dot 4C, the switching element 5C is arranged on the right side of the dot. A signal line 2 for supplying an image signal to each dot electrode 6A, 6B, 6C is arranged on the left side of each dot 4A, 4B, 4C, and a signal branch line 12A, 12 from which the main line of the signal line 2 is branched.
B and 12C are provided for each dot. Each signal branch line 12A, 12B, 12C is connected to each switching element 5A, 5
B and 5C respectively connected to each switching element 5
Image signals are supplied to A, 5B and 5C through signal branch lines 12A, 12B and 12C. In the case of the present embodiment, one end of the signal branch lines 12A, 12B, 12C is connected to the signal line 2, while the other end is connected to the sources of the TFTs that form the switching elements 5A, 5B, 5C. Therefore, since the positions of the switching elements 5A, 5B, 5C are different depending on the dots 4A, 4B, 4C, the lengths of the signal branch lines 12A, 12B, 12C are also different.

The liquid crystal display device of the present embodiment is different from the first embodiment in that the switching elements 5A, 5B and 5C.
And the display electrodes 8R, 8G, and 8B overlap each other in a plane. However, since the number of switching elements 5A, 5B, 5C overlapping with each display electrode 8R, 8G, 8B is equal over all display electrodes 8R, 8G, 8B, each display electrode 8R, 8G, 8B and switching element 5A, 5B,
It is possible to suppress variations in parasitic capacitance formed by 5C and variations in offset voltage. As a result, it is possible to obtain the same effect as that of the first embodiment in that display defects such as flicker and burn-in can be improved while ensuring the degree of freedom in design.

Further, in the first embodiment, since the switching element 5 and the display electrodes 8R, 8G, 8B need to be arranged so as not to overlap each other, the adjacent display electrodes 8R, 8R,
The distance between 8G and 8B differs depending on where the switching element 5 is provided and where it is not provided.
The interval between G and the display electrode 8G and the display electrode 8B is narrow, and the interval between the display electrode 8B and the display electrode 8R is wide. As a result, when a front light is arranged on the upper surface of the liquid crystal display device, interference with the stripes of the light guide plate causes moire fringes, resulting in poor appearance. Further, a black matrix is usually arranged at the place where the switching element 5 is arranged and it cannot contribute to the display, so that there is a problem that the area (aperture ratio) that can contribute to the display becomes small and the image becomes dark. On the other hand, in the liquid crystal display device of the present embodiment, the switching elements 5A,
5B and 5C and the display electrodes 8R, 8G, and 8B overlap each other, so that the display electrodes 8R and 8G, which cannot contribute to the display,
Since the space between 8B can be narrowed with a uniform width irrespective of the place, it is possible to display a bright image with good appearance.

[Third Embodiment] The third embodiment of the present invention will be described below.
An embodiment will be described with reference to FIGS. 6 and 7. The basic configuration of the liquid crystal display device of this embodiment is almost the same as that of the first and second embodiments, and FIG. 7 is a plan view showing only the dot electrodes 6A, 6B, 6C of the liquid crystal display device of this embodiment. FIG. 6 is a plan view showing the display electrodes 8R, 8G, 8B above the dot electrodes 6A, 6B, 6C in an overlapping manner. 6,
7, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the liquid crystal display device according to the first embodiment, all the switching elements 5 have any of the display electrodes 8R, 8G,
8B does not overlap in plan view, the liquid crystal display device of the present embodiment is similar to that of the second embodiment.
As shown in FIGS. 6 and 7, the three switching elements 5A, 5B, 5C in one color pixel 1 overlap with the three display electrodes 8R, 8G, 8B in the color pixel 1 in a plane. ing. In addition, in one color pixel 1, three switching elements 5A, 5B, 5
C overlaps with the other display electrodes 8R, 8G, 8B, and the number of switching elements 5A, 5B, 5C overlapping with the respective display electrodes 8R, 8G, 8B is equal to that of all the display electrodes 8R, 8B.
It is equal over G and 8B.

However, the liquid crystal display device of this embodiment is different from the second embodiment in that, as shown in FIG. 7, the sources of the TFTs, which are the switching elements 5A, 5B and 5C,
While the direction in which the gates and drains are arranged is the extending direction of the scanning lines 3A, 3B, 3C in the second embodiment, it is the extending direction of the signal line 2 in the present embodiment and is rotated by 90 °. That is the point. And each dot 4A, 4B, 4C
A signal branch line 12A provided inside the signal line 2 by branching from the signal line 2;
12B and 12C extend to the ends of the dots 4A, 4B and 4C in the extending direction of the scanning lines 3A, 3B and 3C.
All dots 4A, 4B and 4C have the same length. The source of the TFT is connected in the middle of the signal branch lines 12A, 12B, and 12C, and the gate of the TFT is connected to the scanning line 2.

Also in the liquid crystal display device of this embodiment, the switching elements 5A, 5 overlapping with the respective display electrodes 8R, 8G, 8B.
Since the numbers of B and 5C are equal over all the display electrodes 8R, 8G, and 8B, variations in the parasitic capacitance formed by the display electrodes 8R, 8G, and 8B and the switching elements 5A, 5B, and 5C are suppressed, and as a result, the offset is offset. As a result of suppressing the variation in voltage, it is possible to obtain the same effect as that of the second embodiment in which display defects such as flicker and burn-in can be improved while ensuring the degree of freedom in design.

Further, in the second embodiment, the dot 4
Signal branch lines 12A, 12B, 12 by A, 4B, 4C
Since the lengths of C are different, the display electrodes 8R, 8G, 8
The parasitic capacitance formed by B and the signal branch lines 12A, 12B, 12C was different for the dots 4A, 4B, 4C. On the other hand, in the present embodiment, all dots 4
The signal branch lines 12A, 12B, and 12C have the same length in A, 4B, and 4C, and the display electrodes 8R, 8G, and 8B and the signal branch line 1 have the same length.
Since the areas of the overlapping portions with 2A, 12B, and 12C are equal over all the dots 4A, 4B, and 4C, it is possible to further suppress variations in parasitic capacitance and further improve display quality.

[Fourth Embodiment] The fourth embodiment of the present invention will be described below.
An embodiment will be described with reference to FIGS. 8 and 9. The basic configuration of the liquid crystal display device of the present embodiment is almost the same as that of the first to third embodiments, and FIG. 9 is a plan view showing only the dot electrodes 6A, 6B, 6C of the liquid crystal display device of the present embodiment. FIG. 8 is a plan view showing the display electrodes 8R, 8G, 8B above the dot electrodes 6A, 6B, 6C in an overlapping manner. 8,
9, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the liquid crystal display device of this embodiment,
Similar to the second and third embodiments, as shown in FIGS. 8 and 9, three switching elements 5A, 5B, and 5C in one color pixel 1 display three display elements in the color pixel 1. The electrodes 8R, 8G, and 8B overlap with each other in a plane. In one color pixel 1, the three switching elements 5A, 5B and 5C are different display electrodes 8 respectively.
R, 8G, and 8B overlap each other, and each display electrode 8R, 8
The number of switching elements 5A, 5B and 5C overlapping G and 8B is equal over all display electrodes 8R, 8G and 8B. Further, as shown in FIG. 9, the TF which is the switching elements 5A, 5B and 5C is similar to the third embodiment.
The source, gate, and drain of T are arranged side by side in the extending direction of the signal line 2.

However, the liquid crystal display device of this embodiment is different from the third embodiment in that the third embodiment is different from the third embodiment.
As shown in FIG. 7, one signal branch line 12A, 12B, 12C is provided in each dot 4A, 4B, 4C and one scanning line 3A,
While the dots are provided up to the end portions of the dots in the extending directions of 3B and 3C, in the present embodiment, as shown in FIG.
The point is that one signal branch line 12 which is bent stepwise over the three dots 4A, 4B, 4C in one color pixel 1 is provided. Also, one staircase signal branch line 12
In the middle of, the sources of the TFTs of the three switching elements 5A, 5B, 5C corresponding to the three dot electrodes 6A, 6B, 6C are connected, and the gates of the TFTs are connected to the scanning lines 3A, 3B, 3C. .

Also in the liquid crystal display device of the present embodiment, the switching elements 5A, 5 overlapping the display electrodes 8R, 8G, 8B.
Since the numbers of B and 5C are equal over all the display electrodes 8R, 8G, and 8B, variations in the parasitic capacitance formed by the display electrodes 8R, 8G, and 8B and the switching elements 5A, 5B, and 5C are suppressed, and as a result, the offset is offset. As a result of suppressing the variation in voltage, it is possible to obtain the same effect as that of the second and third embodiments in that display defects such as flicker and burn-in can be improved while ensuring the degree of freedom in design.

Further, in the third embodiment, three signal branch lines 12A, 1 are provided for one display electrode 8R, 8G, 8B.
Although 2B and 12C intersect, in the present embodiment, 1
Since the signal branch line 12 has a stepped shape, only one signal branch line 12 crosses one display electrode 8R, 8G, 8B. Therefore, the area of the overlapping portion of the display electrodes 8R, 8G, and 8B and the signal branch line 12 can be reduced as compared with the third embodiment, and not only the variation of the parasitic capacitance but also the absolute value of the parasitic capacitance can be reduced. it can. As a result, the absolute value of the offset voltage itself can be reduced, the design of the drive circuit can be simplified, and flicker and burn-in can be suppressed, and crosstalk can also be suppressed.

[Fifth Embodiment] The fifth embodiment of the present invention will be described below.
The embodiment will be described with reference to FIGS. 10 and 11. The basic configuration of the liquid crystal display device of the present embodiment is almost the same as that of the first to fourth embodiments, and FIG. 11 is a plan view showing only the dot electrodes 6A, 6B, 6C of the liquid crystal display device of the present embodiment. FIG. 10 is a plan view showing the display electrodes 8R, 8G, 8B above the dot electrodes 6A, 6B, 6C in an overlapping manner. 10 and 11, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the liquid crystal display device of this embodiment, focusing on the arrangement of the switching elements 5A, 5B and 5C,
As shown in FIGS. 10 and 11, the second shown in FIGS.
This is similar to the liquid crystal display device of the embodiment. That is,
The three switching elements 5A, 5B, 5C in one color pixel 1 are overlapped with the three display electrodes 8R, 8G, 8B in the color pixel 1 in a plane, respectively.
The number of switching elements 5A, 5B, 5C overlapping with the respective display electrodes 8R, 8G, 8B is equal to that of all the display electrodes 8R, 8G, 8
Equal across B (one by one).

However, the liquid crystal display device of the present embodiment is different from the second embodiment in the configuration of the signal line 2. In the second embodiment, as shown in FIG. 5, the signal branch lines 12A, 12B, and 12C having different lengths branched from the signal line 2 are provided for each dot 4A, 4B, and 4C. In the present embodiment, as shown in FIG. 11, the main line of the signal line 2 corresponding to one row of dot electrodes 6A, 6B, 6C arranged in the vertical direction in the drawing is branched into three at its root, and each of the branched lines is divided. Three switching elements 5A, 5B, 5C corresponding to the dot electrodes 6A, 6B, 6C in one color pixel 1 are connected to the signal lines 2R, 2G, 2B, respectively.

Also in the liquid crystal display device of the present embodiment, the switching elements 5A, 5 overlapping the display electrodes 8R, 8G, 8B.
Since the numbers of B and 5C are equal over all the display electrodes 8R, 8G, and 8B, variations in the parasitic capacitance formed by the display electrodes 8R, 8G, and 8B and the switching elements 5A, 5B, and 5C are suppressed, and as a result, the offset is offset. As a result of suppressing the variation in voltage, it is possible to obtain the same effect as that of the second to fourth embodiments, in which display defects such as flicker and burn-in can be improved while ensuring the degree of freedom in design. Further, according to the configuration of the present embodiment, the switching elements 5A, 5B, 5C, the signal branch line and the display electrode 8R,
Not only the parasitic capacitance generated between the display electrodes 8R and 8B, but also the parasitic capacitance generated between the signal lines 2R, 2G and 2B and the display electrodes 8R, 8G and 8B.
With 8B, the parasitic capacitance can be made uniform, the variation in the parasitic capacitance can be most reduced among all the embodiments, and the display quality can be improved.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the type of liquid crystal display device is described regardless of whether it is a transmissive type or a reflective type, but the present invention is effective as a line crawling countermeasure in any type. However, it is considered that the reflective type, which does not have the restriction of the aperture ratio, is more feasible. Further, in the case of the reflection type, no backlight is required, so that the power saving effect by the common inversion drive can be further enhanced. Further, in the first embodiment, the effect of the line crawling countermeasure is shown only when the common inversion drive of 3: 1 interlace is performed, but other than 3: 1 interlace, for example, 4: 1 interlace drive, 5: 1 Interlaced drive or the like can also be applied.

Further, the arrangement of the contact holes can be appropriately changed other than the pattern shown in the above-mentioned embodiment, and can be linked with the arrangement of the switching elements, for example. Regarding the layout of the color pixel section,
The dot electrode can also be used as the storage capacitor Cs for holding the signal voltage. As an example, a common electrode for storage capacitance is formed in parallel with the scanning line and below the dot electrode,
It is possible to create a storage capacitor with each dot electrode via the gate insulating film. In this case, the so-called Cson Gate
Instead, it has a Cs on Common structure and is suitable for common inversion drive. Further, according to this structure, since the capacitance added to the scanning line is reduced, the gate driver is formed on the substrate by a T
If an FT or the like is used, it means that the load is reduced, which is advantageous in designing the gate driver.

[0053]

As described above in detail, according to the configuration of the present invention, while utilizing the characteristics of the multiple scanning line system,
By sufficiently reducing the line crawling, it is possible to obtain a liquid crystal display device having excellent image quality, and at the same time, it is possible to achieve power saving. In addition, variations in the parasitic capacitance formed by the second electrode and the switching element can be suppressed, and variations in the offset voltage can be suppressed. Therefore, the degree of freedom in design can be secured, and display problems such as flicker and burn-in can be prevented. Can be improved.

[Brief description of drawings]

FIG. 1 is a plan view showing, in an active matrix substrate constituting a liquid crystal display device of a first embodiment of the present invention, dot electrodes and display electrodes above the dot electrodes in an overlapping manner.

FIG. 2 is a plan view showing only the lower dot electrode of the active matrix substrate.

FIG. 3 is a diagram schematically showing the timing at which an image signal is written in each display electrode and the polarity of the image signal written in each display electrode in the contact arrangement example shown in FIG. 1 (3: 1 interlace).

FIG. 4 is a plan view showing, in an active matrix substrate that constitutes a liquid crystal display device of a second embodiment of the present invention, dot electrodes and display electrodes above the dot electrodes in an overlapping manner.

FIG. 5 is a plan view showing only the lower dot electrode of the active matrix substrate.

FIG. 6 is a plan view showing, in an active matrix substrate that constitutes a liquid crystal display device of a third embodiment of the present invention, dot electrodes and display electrodes above the dot electrodes in an overlapping manner.

FIG. 7 is a plan view showing only the lower dot electrode of the active matrix substrate.

FIG. 8 is a plan view showing, in an active matrix substrate that constitutes a liquid crystal display device of a fourth embodiment of the present invention, dot electrodes and display electrodes above the dot electrodes in an overlapping manner.

FIG. 9 is a plan view showing only the lower dot electrode of the active matrix substrate.

FIG. 10 is a plan view showing, in an active matrix substrate that constitutes a liquid crystal display device of a fifth embodiment of the present invention, dot electrodes and display electrodes above the dot electrodes in an overlapping manner.

FIG. 11: In the same, in the active matrix substrate,
It is a top view which shows only a lower dot electrode.

FIG. 12 is a plan view showing the dot electrodes and the display electrodes above the dot electrodes in an overlapping manner in the active matrix substrate that constitutes the liquid crystal display device already filed by the present inventor.

FIG. 13 is the same as the above, in the active matrix substrate,
It is a top view which shows only a lower dot electrode.

FIG. 14 is a diagram of a conventional 3: 1 interlace and dot inversion drive.

FIG. 15 is a diagram of a conventional 3: 1 interlace and common inversion drive.

[Explanation of symbols]

1 color pixel 2,2R, 2G, 2B signal line 3A, 3B, 3C scanning lines 4A, 4B, 4C dots 5,5A, 5B, 5C switching element 6A, 6B, 6C dot electrode (first electrode) 7 contact holes 8R, 8G, 8B Display electrode (second electrode) 12,12A, 12B, 12C Signal branch line

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H092 GA13 GA21 GA23 GA26 GA29                       GA30 JB02 JB04 JB05 JB31                       NA01 NA23 NA26                 2H093 NA31 NA45 NA63 ND10 ND12                       ND39

Claims (5)

[Claims] 1. A liquid crystal is sandwiched between a pair of substrates arranged to face each other, and a plurality of signal lines and a plurality of scanning lines are provided in a matrix on one substrate of the pair of substrates, A plurality of pixels having different basic colors are provided, and one pixel includes dots for the number of basic colors surrounded by adjacent signal lines and adjacent scanning lines, and each pixel includes each dot. A switching element electrically connected to the scanning line and each signal line and a first electrode electrically connected to the switching element are provided, and an insulating layer covering the first electrode in each pixel. A second number of the basic colors, which are formed on the first electrode and electrically connected to the first electrode through a contact hole penetrating the insulating layer.
Electrodes are provided, each second electrode is arranged over the first electrodes for the number of basic colors, and one second electrode is electrically connected to only one of the first electrodes for the number of basic colors. Liquid crystal, wherein one first electrode is electrically connected to only one second electrode, and the switching element and the second electrode are arranged so as not to overlap in a plane. Display device. 2. A liquid crystal is sandwiched between a pair of substrates arranged to face each other, and a plurality of signal lines and a plurality of scanning lines are provided in a matrix on one substrate of the pair of substrates, A plurality of pixels having different basic colors are provided, and one pixel includes dots for the number of basic colors surrounded by adjacent signal lines and adjacent scanning lines, and each pixel includes each dot. A switching element electrically connected to the scanning line and each signal line and a first electrode electrically connected to the switching element are provided, and an insulating layer covering the first electrode in each pixel. A second number of the basic colors, which are formed on the first electrode and electrically connected to the first electrode through a contact hole penetrating the insulating layer.
Electrodes are provided, each second electrode is arranged over the first electrodes for the number of basic colors, and one second electrode is electrically connected to only one of the first electrodes for the number of basic colors. Are electrically connected to each other, one first electrode is electrically connected to only one second electrode, and in each pixel, at least one of the plurality of switching elements and one of the plurality of second electrodes are connected to each other. One of the switching elements is arranged so as to overlap with one in a plane, and the number of the switching elements overlapping each second electrode is equal to that of all the second elements .
A liquid crystal display device characterized by being equal over electrodes . 3. A signal branch line that branches from the signal line and extends to an end of the dot in the extending direction of the scanning line is provided in each dot, and the switching element provided in the dot is provided. The liquid crystal display device according to claim 2, wherein the liquid crystal display device is electrically connected to the signal branch line. 4. A signal branch line extending stepwise over a plurality of dots in the pixel is provided in each pixel, and the plurality of switching elements provided in the pixel are electrically connected to the signal branch line. Claim 2 characterized by the above.
The liquid crystal display device according to item 1. 5. The signal lines for the basic color number corresponding to the dots for the basic color number forming one pixel are provided in parallel with each other, and the end portions of the signal lines for the basic color number are electrically connected. The liquid crystal display device according to claim 2, wherein the liquid crystal display device is connected.