JPH09269478A - Display device capable of assigning intensity levels - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display a high quality picture having high uniformity by setting wiring resistance of low resistance electrically conductive materials so that a wiring resistance corresponding to a first subpixel becomes lower than the wiring resistance corresponding to a second subpixel whose area smaller than that of the first subpixel to dissolve the variation of driving waveforms due to inuniformity of area of subpixels. SOLUTION: Wiring resistances of low resistance electrically conductive materials MIw, MIn connected to transparent electrodes MOw, MOn of a pixel are set so that a wiring resistance corresponding to a first subpixel SPw having a larger area between at least two subpixels SPw, SPn which constitute each pixel and have different areas becomes lower than the wiring resistance of a second subpixel SPn whose area is smaller than that of the first subpixel SPw. Consequently, delay characteristics of a drive waveform become roughly equal to or have negligible difference from each other even in all pixels even though all pixels are driven by drivers IC of the same driving abilities. Thus, it is possible to obtain displays having high uniformity over the whole of a screen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device in which scanning signal lines and information signal lines are arranged in a matrix, and a scanning signal and an information signal are respectively applied to drive the display device. It belongs to the technology of a display device capable of performing gradation display by dividing into subpixels.

[0002]

2. Description of the Related Art Heretofore, various methods have been proposed for expressing multiple gradations in a liquid crystal display (LCD).
(1) The first method is a method of controlling an applied voltage to each pixel according to an applied voltage-transmittance curve to obtain a desired level of luminance. This is well known as a gradation control method of an active matrix LCD using a TN liquid crystal. Further, even when a ferroelectric chiral smectic liquid crystal is used, there is a method of controlling the area ratio of so-called domains in two alignment states.
712,877, USP 4,796,980, USP
No. 4,824,218 and US Pat. No. 4,776,676. However, in the method (1), when the applied voltage-transmittance curve is very steep, the transmittance (brightness) of the liquid crystal greatly changes due to a small error in the applied voltage, and a predetermined level of brightness is obtained. Was difficult to output accurately.

(2) The second method is a method of dividing one frame into several sub-frames and performing multi-gradation display by time-modulating ON / OFF of pixels. , 995, and the like.

In the above method (2), the control circuit becomes complicated, and high-speed scanning is required in order to suppress flicker, so that the load on the display element and peripheral circuits may be increased.

Therefore, as another method, (3) a plurality of pixels (sub-pixels) having different areas are grouped as a set, and a plurality of pixels (sub-pixels) having different areas are lit in various patterns to form a multi-level display. There is a way to display the key. This is the case for EP261,898, EP361,981, EP
453,033.

A specific example of (3) and its characteristics will be described with reference to FIGS. 1 (a), 1 (b), 1 (c) and FIG.
It should be noted that any of the specific examples of (a), (b), and (c) of FIG. 1 performs multi-gradation display of 16 levels, and the pixel division configuration of the display element in each example is different from that of the product. It is selected according to the application form (purpose).

When viewed from the entire screen of the display element, at least two pixels having different areas are mixed, but from a different viewpoint, one pixel is formed by at least two sub-pixels having different areas. It is also possible to proceed with the explanation from the latter point of view.

In the specific examples shown in FIGS. 1A and 1B,
As a set of four sub-pixels, these four sub-pixels form a pixel capable of multi-tone display. And 0
In order to obtain 16 linear optical levels from 1 to 15, the area ratio of these sub-pixels is 8: 4: 2: 1,
The electrodes corresponding to each sub-pixel are selectively driven sequentially in accordance with the pixel information.

FIGS. 1A and 1B are different only in the arrangement of four sub-pixels. Further, for example, the sub-pixel shown in FIG. 1A is formed by the intersection of four information electrodes and one scanning electrode. Is set to be 8: 4: 2: 1. Here, as is well known, these electrodes are formed on a pair of substrates arranged to face each other.

As described above, the area ratio of the sub-pixels is 2 ⁿ : 2
^A linear optical level can be obtained by setting ^n-1 :...: 2 ¹ : 2 ^{0. In} general, however, in order to obtain a more natural image in this method, a dither method or an error diffusion method is used. And other image processing.

In the concrete example shown in FIG. 1C, a set of sub-pixels having an area ratio as shown in FIG. 1 is set, and electrodes corresponding to the sub-pixels having different areas are set in accordance with image information. And selectively drive sequentially. As a result, as shown in FIG. 2, the white display portion is vertically symmetrical (or horizontally symmetrical).
To be placed in. Therefore, when this pattern is used, the center of the ON region (white display portion) is at the center of the pixel and does not change at any gradation. Therefore, the so-called pseudo contour, which is caused when the position of the center of gravity of the light largely moves due to the gradation pattern, does not deteriorate.

At least one of the pair of electrodes forming a pixel of such a liquid crystal panel is preferably formed of a transparent conductive oxide, and examples of such a material include tin oxide, indium oxide, and indium oxide. Tin (ITO) or the like is used. In recent years, with the increase in display area and the increase in definition, low resistance conductors made of metal such as Al and Cu having a lower resistance than transparent conductors have been used as countermeasures for delaying drive waveforms in the panel. Some have a configuration with wiring.

[0013]

In the case of a display element in which one pixel is divided into a plurality of sub-pixels having different areas to perform multi-gradation display, the above-mentioned metal wiring has the same wiring width and the same film over the respective sub-pixels. If it is formed with a large thickness, the load (wiring resistance x electrode capacitance) seen from one drive circuit will be different for each subpixel, and the delay characteristics of the drive waveform applied to the liquid crystal (waveform rise and fall times). Difference occurs. This causes variations in the switching characteristics of the liquid crystal for each sub-pixel, and as a result, there is a problem of image quality deterioration such as luminance unevenness of a screen and deterioration of gradation.

Further, in order to solve the above-mentioned problem, it is conceivable to adjust the driving capability of the driving circuit (driver IC) according to the size (load) of the (sub) pixel of the panel to be connected. However, this increases the load on the design of the drive circuit, and at the same time loses the versatility of the driver IC. That is, it cannot be diverted to a panel having another pixel arrangement.

According to the present invention, in a display element in which one pixel is divided into a plurality of sub-pixels having different areas, a drive waveform (applied waveform to the display element) due to non-uniformity of the area of the sub-pixels.
It is an object of the present invention to provide a display device capable of displaying a high-quality image with high uniformity by eliminating the variation of the above.

[0016]

The present invention provides a display device in which one pixel is divided into a plurality of sub-pixels having different areas,
Among the at least two sub-pixels having different areas forming each pixel, the wiring resistance corresponding to the first sub-pixel having a large area is the wiring resistance of the second sub-pixel having a smaller area than the first sub-pixel. In the display device, the wiring resistance of the low-resistance conductor connected to the transparent electrode of the pixel is set to be lower.

Further, according to the present invention, in a display device in which one pixel is divided into a plurality of sub-pixels having different areas, at least one of the information electrode group or the scanning electrode group is a first transparent conductive film having a first area. A first connected to the first transparent conductive film
A low resistance conductor, a second transparent conductive film having a second area smaller than the first area, and a second low resistance conductor connected to the second transparent conductive film. An electrode having a wiring resistance of the first low resistance conductor
Is lower than the wiring resistance of the low-resistance conductor.

According to the display device as described above, even if all the pixels are driven by the driver ICs having the same driving capability, the delay characteristics of the driving waveforms are almost the same in all the pixels, or the difference can be ignored. It is possible to obtain a display with high uniformity over the entire screen.

[0019]

FIG. 3 shows a pixel configuration of a display device according to an embodiment of the present invention.

Here, a non-active matrix type display panel is taken as an example, MC is a low resistance conductor wiring as a scanning electrode, and MO is a high resistance transparent electrode connected to the wiring MC. Here, low resistance and high resistance refer to relative height. The scan electrode group is arranged on the common substrate.

On the other hand, MIw and MIn are low resistance conductor wires as information electrodes, and MOw and MOn are high resistance transparent electrodes. The information electrode group is arranged on another common substrate.

The overlapping portion of the transparent electrode MO and the transparent electrode MOw or the overlapping portion of the transparent electrode MO and MOn serves as a sub-pixel.

Here, the transparent electrode MO is made of a continuous transparent conductive film having a strip shape, while the transparent electrodes MOw and MOn are made of a transparent conductive film having a strip shape divided according to the area of the sub-pixel.

For example, two large and small subpixels SPw and S shown in FIG.
One pixel is composed of Pn, and only two pixels are shown in FIG.

LI is an information line terminal, and LC is a scanning line terminal, which are connected to the drive circuit. The wiring resistance is
It is the entire resistance value from the terminal of one low-resistance conductor provided with a transparent electrode to the other end, and is the resistance value when one scanning line is viewed as an individual resistor.

Here, the wirings MIw and M as information electrodes
Ins have different widths w1 and w2. Here, the sub-pixel SPw formed by the transparent electrode M0w is larger than the sub-pixel SPn formed by the transparent electrode MOn. Therefore, the width w1 of the wiring MIw is larger than the width w2 of the wiring MIn. Since both wirings have almost the same thickness, the wiring resistance is determined depending on the width. Such a structure can be formed in the same photolithography process.

Therefore, if the subpixel size ratio is a power of 2, the wiring width ratio should be a power of 2.

In the example of FIG. 3, if the area ratio of the sub-pixels is 2: 1, the ratio of the width w1 and the width w2 is w1: w2 = 2: 1.

Examples of the low-resistance conductor used in the present invention include metals such as Al, Cr, Ni, Ti, Cu, Ta, W and Mo or alloys thereof, or aluminum oxide containing CrN or Ag. It is sufficient that the resistance is lower than that of the transparent electrode. More preferably, as the low resistance conductor, it is desirable to use a material having a specific resistance of 1/100 of the transparent electrode, and optimally 1/1000 or less.

Examples of the transparent electrode used in the present invention include tin oxide, indium oxide, ITO, ZnO and IrO.

Of course, by arranging a large number of pixels as shown in FIG. 3,
It may be a color display element provided with a color filter.
Especially when a color filter having a light-shielding mask is provided, the size of the sub-pixel is optically determined by the area of the transmission part of the color filter. Therefore, in the case of the present invention, the wiring resistance ratio should be determined by the area of the transparent electrodes MOw and MOn, instead of corresponding to the area ratio of the transparent portion of the color filter.

The present invention is preferably applied to a liquid crystal element in which a liquid crystal is arranged between a pair of transparent electrodes.

As the liquid crystal, a ferroelectric or antiferroelectric chiral smectic liquid crystal exhibiting two alignment states or 2
Chiral nematic liquid crystals exhibiting two metastable states are preferred. Devices using the former are known as FLCDs and AFLCDs, and devices using the latter are known as BTNLCDs.

The present invention is applicable not only to non-active matrix type elements but also to active matrix type elements.

[0035]

【Example】

Embodiment 1 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 4 is a block diagram of the drive system of the display device according to the first embodiment of the present invention. As shown in FIG. 5, this display device includes a liquid crystal display element 1 in which a substrate 1a having a scanning electrode group C and a substrate 1b having an information electrode group I are arranged so as to face each other as shown in FIG. As its drive system, a scan electrode drive circuit 2 for driving the scan electrode group C,
An information electrode drive circuit 3 for driving the information electrode group I, a drive voltage generation circuit 4 for applying a drive voltage to each drive circuit, a scan electrode drive control signal to the scan electrode drive circuit 2, A panel control circuit 5 that supplies an information electrode drive control signal and an image signal to the circuit 3 and a display data generator 6 that supplies image information to the panel control circuit 5 are provided. Alternatively, the light source has a fluorescent lamp such as a three-wavelength tube. These components serve as driving means for driving the display element according to the present invention.

FIG. 5 is a diagram schematically showing a part of the constitution of the liquid crystal display element 1 in this display device.
5A is a plan view, and FIG. 5B is an enlarged view of one pixel of the liquid crystal display element. The above-mentioned display element 1 uses a ferroelectric liquid crystal display element here,
Although FIG. 5 shows only 3 pixels on the information electrode side and 2 pixels on the scanning electrode side, for a total of 6 pixels, in reality, 12 pixels for each color.
It has 80 × 1024 pixels.

As shown in FIG. 5, the liquid crystal display element 1 in this embodiment is a color display in which one pixel is made up of different sub-pixels having an area ratio of 1: 2 and an RGB color filter is provided at that one pixel. There is. In each RGB pixel, the information electrode is divided into Iw and In having different widths, and the scanning electrode is not divided or divided (only Ca). As a result, 2 bits per color (4 gradations),
It is possible to display 6-bit (64 ways) colors per pixel.

MIw and MIn of FIG. 5B are metal wirings provided together to reduce the resistance of the information electrodes Iw and In. As described above, the information electrode of each RGB pixel is divided into Iw and In, and in order to express gradation linearly, the area thereof is designed to be Iw> In and the ratio thereof is designed to be 2: 1. Therefore, the electric capacity per information electrode is 2: 1.
So Iw is bigger. Therefore, in this embodiment, the resistance value of the metal wirings MIw and MIn is set to MIw <MIn, and the ratio thereof is set to 1: 2. By doing so, the electrical load of one information electrode is almost the same (here, Ci
xRi means the same, and Ci can be a capacitance value of a certain information electrode i, and Ri a wiring resistance value of a certain information electrode i). Strictly speaking, the transparent electrode contributes to the wiring resistance, but using ITO for the transparent electrode and Al for the metal wiring, it is very common to design the wiring width and film thickness to maintain the aperture ratio. And 90% or more of the total wiring resistance is determined by the resistance value of the metal wiring portion. Therefore, in this embodiment, the resistance value of the metal wiring is simply set to 1: 2. By doing so, even if the pixels have different areas, the electrical load of the information electrode viewed from one drive circuit becomes constant, so that the delay characteristics of the drive waveform are uniform, that is, the drive conditions of each pixel are the same. Thus, it is possible to realize high-quality display without unevenness over the entire screen.

As a modification, I can be used as a scanning electrode group and C can be used as an information electrode group.

(Embodiment 2) Next, another pixel configuration of the display element according to Embodiment 2 of the present invention will be described. FIG. 6 is a diagram schematically showing a part of the configuration of the liquid crystal display element.
6A is a plan view, and FIG. 6B is an enlarged view of one pixel of the liquid crystal display element.

As shown in the figure, this embodiment is similar to FIG. 1C so that the position of the center of gravity of the light quantity of each gradation pattern of each pixel is always at the pixel center in order to eliminate the false contour. It has a sub-pixel configuration. Strictly speaking, in this example, a slight shift of the center of gravity occurs in the lateral direction in each color (RGB), but the moving distance that can be set in the entire pixel area is small, and there is no problem in the case of this example. Of course, a configuration of sub-pixels in which the center of gravity does not move in all directions can also be realized (for example, the pattern of (c) in FIG. 1). In each RGB pixel, the information electrode is divided into Iw and In having different widths, and the scanning electrode is divided into Ca, Cb, and Cc. Among them, Ca and Cc of the scan electrodes are electrically short-circuited and the scan electrode drive signal is applied at the same time, so that they are substantially divided into two. As a result, it is possible to express 4 bits per color (16 gradations) and 12 bits per pixel (4096 colors).

Also in this embodiment, as in the first embodiment, the resistance values of the metal wirings MIw and MIn of the information electrodes are the same as those of the sub-pixel I.
It is set in a form inversely proportional to the area ratio of w and In. That is, in this example, the area ratio between the sub-pixels Iw and In of the information electrode is
Since it is designed to be 2: 1, it is designed to have a resistance value of MIw = 1/2 × MIn by adjusting the wiring width of the metal wiring. Further, in the present example, the metal wiring on the scan electrode side is also MCa.
Resistance value of MCc = resistance value of MCc = 1/2 × MCb.

In this example, the information electrode group I and the scanning electrode group C are both two types of low resistance conductors MIw, MIn, MCa (MC
c), MCb was used. However, since a normal display device is long in the horizontal scanning direction and the amplitude of the voltage applied to the scan electrodes is larger than the amplitude of the voltage applied to the information electrodes, the problem of the drive voltage waveform collapse at the scan electrodes is significant. is there.

Therefore, when each of the information electrode and the scanning electrode has two or more transparent conductive films having different areas, it is desirable to adopt the constitution of the present invention at least for the scanning electrode group.

(Third Embodiment) The display device according to the third embodiment shown in FIG. 7 is obtained by changing the arrangement of sub-pixels of the display device of the second embodiment.

That is, along the horizontal scanning direction DHS, from the left in FIG. 7, red sub-pixels (R4, R2, R).
4 '), green sub-pixels (G3, G1, G3'), blue sub-pixels (B4, B2, B4 '), red sub-pixels (R3,
R1, R3 '), green sub-pixels (G4, G2, G
4 ') and blue sub-pixels (B3, B1, B3') are repeatedly arranged in this order.

With this pattern, gradation display of 16 gradation levels for each color can be performed. In the case of red display, for example, in this gradation display mode, the sub-pixels R4 and R4 ′ both have the same display state, and the sub-pixels R3 and R3 ′ both have the same display state.

In order to form such a display state and to increase the vertical scanning speed, the scanning selection signals are simultaneously input to the terminals C1 and C3, and the scanning electrodes connected to the terminals C1 and C3 are simultaneously selected. .

Next, scan selection signals are simultaneously input to the terminals C4 and C6, and the scan electrodes connected to C4 and C6 are simultaneously selected.

This selection is sequentially performed in the vertical scanning direction DVS to complete one vertical scanning.

In the next vertical scanning period, the scanning selection signal is sequentially applied to each of the scanning electrodes connected to the terminals C2 and C5 to perform scanning selection.

Thus, the sub-pixels or sets of sub-pixels that serve as the gradation reference are R1, R2, R3 and R3 ', and R4 and R'.
And the area ratio of these four is 1: 2: 4 :.
It is 8.

The gradation display method for other colors, that is, green and blue, is the same as that for red.

L1 to L6, L7 to L12, L13 to L1
Reference numeral 8 denotes an information signal input terminal, which is a metal wiring RMIw, GMIn, BMIw, RMIn, GM which is a low resistance conductor.
It is connected to Iw and BMIn.

The terminals L1 to L6 and L13 to L18 are connected to a drive circuit (not shown) at one end of the display panel, and the terminal L
7 to L12 are connected to a drive circuit (not shown) at the other end of the display panel.

With this configuration, the arrangement density of terminals can be reduced.

The wiring resistance of RMIw, GMIw, and BMIw is one half of the wiring resistance of RMIn, GMIn, and BMIn, and the wiring resistance of the metal wiring MCa or MCc is also
It is half the metal electrode MCb.

In order to obtain such wiring resistance, the metal electrodes have the same film thickness and different widths.

FIG. 8 is a schematic view showing a cross section of the display panel according to this embodiment.

This display panel comprises a pair of substrates 11a and 11a.
It is a panel in which the liquid crystal 15 is arranged between b.

The transparent conductive film 12 is formed on the inner surface of the substrate 11a.
a and an alignment film 14a are provided. Reference numeral 13a is an insulating film provided as needed.

On the other hand, an alignment film 14b is provided on the transparent conductive film 12b on the inner surface of the substrate 11b. A metal electrode as a low resistance conductor is provided on each transparent electrode. 13b is an insulating film provided as necessary. The distance between the two substrates 11a and 11b is maintained at about 1 to 10 μm by the spacer 165. 17a and 17b are polarizing plates.

(Embodiment 4) The display device of this embodiment shown in FIG. 9 is obtained by changing the area ratio of the sub-pixels of the device shown in FIG. 7. Specifically, the width ratio of the scanning electrodes is changed. 2.5: 1.0: 1.5: 1.5: 1.0: 2.5 from top to bottom in the figure, and this pattern is repeated in the vertical scanning direction (DV).
It is lined up in S).

A characteristic point of this example is that an image can be displayed in two display modes having different resolutions and different numbers of gradation levels.

First, the low resolution / high gradation display mode will be described by focusing on red. This mode is the same as in the third embodiment.
First, a scan selection signal is applied to the scan electrodes connected to the terminals C1 and C3 at the same time to display the display states of the sub-pixels R4, R4 ′, R3, and R3 ′ on the two scan electrodes. Establish.

Next, the scanning selection signals are simultaneously applied to the terminals C4 and C6 to determine the display states of the sub-pixels R4 ', R4, R3' and R3.

When this is repeated to complete the first vertical scanning, the second vertical scanning for determining the display state of the sub-pixels R2, R1 is performed by applying the sequential scanning selection signal to the terminals C2, C5. Thus, one frame scan is completed by the first and second vertical scans.

Next, the high resolution and low gradation display mode will be described.

One pixel in this case is composed of three sub-pixels R4, G3 and B4, which is different from the one in the low resolution / high gradation display mode described above.

Another pixel adjacent in the DHS direction is composed of three sub-pixels R3, G4 and B3.

One pixel adjacent in the DVS direction has six sub-pixels R
2, R4 ′, G1, G3 ′, B2, B4 ′, and one pixel adjacent in the DVS direction is six sub-pixels R4 ′,
It is composed of R2, G3 ', G1, B4', and B2.

In this display mode, a total of 72 sub-pixels shown in FIG. 9 can display 16 pixels. In the low resolution / high gradation display mode described above, only four pixels can be displayed.

This mode is suitable when the smoothness of the character font is preferentially given such as character input display such as alphabets, numbers and kana characters rather than the number of display colors.

The scan selection signal is supplied to the terminals C1, C2 and C.
3. If the voltages are sequentially applied in the order of 3, terminals C4 and C5, and terminal C6, one frame scanning by non-interlace is completed.

By alternately arranging the two low-resistance conductors having different wiring resistances and sequentially arranging the three colors in this manner, display in two display modes can be performed at least in the horizontal scanning direction.

Further, as shown in FIG. 9, the length (that is, the pixel division ratio) of the sub-pixels in the vertical scanning direction is made different from each other, and the area of the largest sub-pixel in the DVS direction and the remaining sub-pixels are set. If the sum of the areas of the two is substantially equal to each other, display in two display modes can be performed even in the vertical scanning direction.

Example 5 A display panel having the pixel pattern shown in FIG. 9 and having the same sectional structure as the section shown in FIG. 8 was manufactured as follows.

ITO having a film thickness of 1500 Å was formed on one of the glass substrate 11b of 240 mm × 300 mm by sputtering. A 1500 Å film of molybdenum (Mo) was formed thereon by sputtering. The Mo film was patterned by photolithography so that the film having a width of 20 μm and the film having a width of 10 μm were alternately arranged.

Further, the width is 200 by photolithography.
The ITO was patterned to have stripes of 100 μm and 100 μm.

The wiring resistance of the electrodes made of ITO having a width of 100 μm and Mo having a width of 10 μm and a length of 220 mm is 3.0K.
Ω, 200 μm width ITO and 20 μm width and length 220
The wiring resistance of the electrode due to Mo of 1.5 mm was 1.5 KΩ.

After that, a tantalum oxide film was formed as the insulating film 13b, and a polyimide film was formed as the alignment film 14b.

Similarly, ITO patterned to have a width ratio of 2.5: 1.0: 1.5 was formed on the glass 11a as the upper substrate. Mo films of 25 μm, 10 μm, and 1.5 μm widths were formed on the upper substrate according to the width of ITO. A tantalum oxide film and a polyimide film were formed.
Polyimide films 14a and 14 on the surfaces of both substrates 11a and 11b
b was rubbed.

The glass substrate 11 manufactured in this way
a and 11b are dispersed on one glass substrate 11a (11b) with bead spacers 16 (silica beads, alumina beads, etc.) having an average particle size of about 1.2 μm, and the other glass substrate 1
A seal adhesive, which is an epoxy resin adhesive, is formed on 1a and 11b by a screen printing method.
The cells shown in FIG. 8 were prepared by laminating 11b. Note that the rubbing treatment performed on the bonded glass substrates 11a and 11b was performed so that the rubbing directions were substantially parallel to each other.

Then, a pyrimidine-based ferroelectric liquid crystal exhibiting the following phase transition temperature and physical properties was heated to the Iso phase under reduced pressure, injected by a capillary phenomenon, and then slowly cooled to manufacture a liquid crystal device. When this device was driven and the alignment state was observed, it was observed that the alignment was in a uniform state. When the angle formed by the uniaxial orientation treatment direction of one substrate 11a and the uniaxial orientation treatment direction of the other substrate 11b is θ _C , θ _C satisfies the relation of 0 ° <θ _C <20 °. I have to.

[0086] Tilt angle θ = 15.1 ° (at 30 ° C.) Spontaneous polarization Ps = 5.5 (nc / cm ² ) (at 30
℃)

When a known drive waveform was applied to the thus-obtained display panel to perform display, no change in luminance occurred for each electrode, that is, for each line.

As a comparative sample, the width of the Mo film was all 2
When a sample having a thickness of 0 μm and all other structures having the same structure as the panel of Example 5 was prepared and displayed,
The brightness seemed to differ from line to line.

(Sixth Embodiment) Similar to the third embodiment described above, FIG.
A liquid crystal panel having the electrode structure shown in was produced.

Two glass substrates having a size of 240 mm × 300 mm were prepared, and a Mo film having a thickness of 2 μm was formed on one of the glass substrates by magnetron sputtering and heat-treated to reduce the specific resistance. Next, patterning is performed by photolithography, and ITO is formed and patterned to a thickness of 1500 Å,
The wiring MCb has a length of 290 mm, a width of 9 μm, a resistance value of 400 Ω,
A scanning electrode substrate 1a having wirings MCa and MCc having a length of 230 mm and a resistance value of 18 μm of 800Ω was manufactured.

ITO on the other glass substrate 1500 Å
Deposition and patterning with a thick thickness, and further Mo film with 2500 Å
Mo wiring R with a width of 11 μm is formed by thick film formation and patterning
MIw, BMIw, GMIw, Mo wiring G with a width of 9 μm
Information electrode substrate 1 on which MIn, RMIn, and BMIn are formed
b was prepared. Then, a liquid crystal was filled in the same manner as in Example 5 to prepare a liquid crystal panel.

[0092]

EFFECTS OF THE INVENTION In a display element in which one pixel is divided into a plurality of sub-pixels having different areas and gradation display is possible, the drive waveform (waveform applied to the display element) varies due to non-uniformity of the sub-pixel area. Therefore, it is possible to provide a display element capable of displaying a high-quality image with high uniformity.

Further, a dedicated driver IC whose drive capability is adjusted according to the size (load) of the (sub) pixels of the panel
There is no need to prepare.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a pixel dividing method of a conventional display device.

FIG. 2 is a diagram showing a conventional gradation display pattern.

FIG. 3 is a diagram showing a configuration of a display device according to an embodiment of the present invention.

FIG. 4 is a diagram showing a control system of the display device according to the first embodiment.

FIG. 5 is a diagram showing a pixel configuration of a display device according to Example 1.

FIG. 6 is a diagram showing a pixel configuration of a display device according to a second embodiment.

FIG. 7 is a diagram showing a pixel configuration of a display device according to a third embodiment.

FIG. 8 is a cross-sectional view of a display panel used in the present invention.

FIG. 9 is a diagram showing a pixel configuration of a display device according to a fourth embodiment.

[Explanation of symbols]

 MIw, MIn Low resistance conductor MOw, MOn Transparent electrode SPw, SPn Sub-pixel 11a, 11b Substrate 12a, 12b Transparent conductive film 13a, 13b Insulating film 14a, 14b Alignment film 15 Liquid crystal 16 Spacer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tadashi Mihara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (45)

[Claims] 1. A display device in which one pixel is divided into a plurality of sub-pixels having different areas, and a first one having a larger area among at least two sub-pixels having different areas forming each pixel.
The wiring resistance of the low resistance conductor connected to the transparent electrode of the pixel is lower than the wiring resistance of the second subpixel having a smaller area than that of the first subpixel. A display device characterized by being set. 2. The display device according to claim 1, wherein the wiring resistance value ratio is set to be inversely proportional to the pixel area ratio of the sub-pixels. 3. The display device according to claim 1, wherein the pixel is a pixel whose display state is determined according to a wiring state of a chiral nematic liquid crystal or a chiral smectic liquid crystal. 4. The display device according to claim 1, wherein the low resistance conductor is a metal having a lower resistance than a transparent electrode. 5. The display device according to claim 1, wherein the low-resistance conductor has a different width depending on the size of the sub-pixel. 6. The display device according to claim 5, wherein all the low resistance conductors have the same thickness. 7. Among the at least three sub-pixels having different areas forming each pixel, the wiring resistance corresponding to the sub-pixel having the largest area is the lowest, and the wiring resistance of the sub-pixel having the smallest area is the highest. The display device according to claim 1, wherein the wiring resistance of the low-resistance conductor is set in the. 8. The display device according to claim 7, wherein the ratio of the wiring resistance values is set to be inversely proportional to the ratio of the pixel areas of the sub-pixels. 9. The display device according to claim 7, wherein the pixel is a pixel whose display state is determined according to a wiring state of a chiral nematic liquid crystal or a chiral smectic liquid crystal. 10. The display device according to claim 7, wherein the low resistance conductor is a metal having a resistance lower than that of the transparent electrode. 11. The display device according to claim 7, wherein the low-resistance conductor has a different width depending on the size of the sub-pixel. 12. The display device according to claim 1, wherein low resistance conductors having different wiring resistances are alternately provided in the horizontal scanning direction or the vertical scanning direction. 13. The display device according to claim 1, wherein low resistance conductors having different wiring resistances are alternately provided in a horizontal scanning direction and a vertical scanning direction. 14. A transparent electrode corresponding to first and second sub-pixels having different areas is connected to the first low-resistance conductor having a predetermined wiring resistance, and the wiring resistance higher than the predetermined wiring resistance. 8. The display device according to claim 1, wherein transparent electrodes corresponding to third and fourth sub-pixels having different areas are connected to the second low-resistance conductor having. 15. The display device according to claim 14, wherein the first and second sub-pixels are on the same scanning line, and the third and fourth sub-pixels are on another same scanning line. 16. The area of the sub-pixel provided corresponding to the first low resistance conductor having a predetermined wiring resistance corresponds to the second low resistance conductor having a wiring resistance higher than the predetermined wiring resistance. The display device according to claim 1 or 7, wherein the display area is 1.5 to 2.5 times the area of the sub pixel provided. 17. The first low resistance conductor is provided with at least two sub-pixels having different areas.
The display device according to claim 1. 18. The second low resistance conductor is provided with at least two sub-pixels having different areas.
The display device according to item 6. 19. The first or second low resistance conductor is provided with at least three sub-pixels having different areas, and the sub-pixel having the smallest area is between the remaining two sub-pixels. 16. The display device according to 16. 20. The display device according to claim 1, wherein the sub-pixel includes a plurality of sub-pixels having different colors. 21. The display device according to claim 1, wherein the display device is a color display device, and the same low-resistance conductor is provided corresponding to sub-pixels of the same color. 22. The sub-pixel comprises sub-pixels of three colors, wherein first and second low resistance conductors having different wiring resistances are alternately arranged in the horizontal scanning direction, and the first and second low-resistance conductors are arranged in the horizontal scanning direction. 8. The display device according to claim 1, wherein the sub-pixels of the first to third colors are repeatedly arranged. 23. The display device according to claim 1, wherein the first to third colors are red, green and blue. 24. The display device according to claim 1, further comprising a light source. 25. The display device according to claim 1, further comprising a signal source that generates an image signal to be supplied to the display device. 26. In a display device in which one pixel is divided into a plurality of sub-pixels having different areas, at least one of the information electrode group or the scanning electrode group has a first transparent conductive film having a first area and the first transparent conductive film. An electrode having a first low-resistance conductor connected to the first transparent conductive film, a second transparent conductive film having a second area smaller than the first area, and a second transparent conductive film. An electrode having a second low resistance conductor connected thereto, wherein the wiring resistance of the first low resistance conductor is lower than the wiring resistance of the second low resistance conductor. . 27. The display device according to claim 26, wherein each of the first and second transparent conductive films is a strip-shaped film divided into a size corresponding to the sub-pixel. 28. The display device according to claim 26, wherein the first and second transparent conductive films are continuous strip films. 29. The first and second low resistance conductors,
27. The display device according to claim 26, which is made of the same material having a lower resistance than that of the transparent conductive film and has different widths. 30. The first and second low resistance conductors,
30. The display device according to claim 29, having the same thickness. 31. The first transparent conductive film is a transparent electrode forming at least two sub-pixels having different areas, and the second transparent conductive film has an area different from that of the at least two sub-pixels. 27. The display device according to claim 26, which is a transparent electrode forming a subpixel. 32. The display device according to claim 26, wherein the first and second low resistance conductors are alternately provided in a horizontal scanning direction or a vertical scanning direction. 33. The display device according to claim 26, wherein the first and second low-resistance conductors are provided alternately in the vertical scanning direction. 34. The first low resistance conductors are connected to transparent electrodes corresponding to the first and second sub-pixels having different areas, and the second low resistance conductors have different areas. Transparent electrodes corresponding to the third and fourth subpixels are connected,
27. The display device according to claim 26, wherein the first and second sub-pixels are on the same scanning line, and the third and fourth sub-pixels are on another same scanning line. 35. An area of a subpixel provided corresponding to the first low resistance conductor is provided corresponding to the second low resistance conductor and is on the same electrode as the subpixel. The display device according to claim 1, which is larger than the area. 36. At least three sub-pixels having different areas are provided on the electrode having the first or second low resistance conductor, and the sub-pixel having the smallest area is between the remaining two sub-pixels. 27. The display device according to claim 26, wherein the display device is arranged in. 37. The display device according to claim 26, wherein the sub-pixel includes a plurality of sub-pixels having different colors. 38. The display device according to claim 26, wherein the display device is a color display device, and the same low-resistance conductor is provided corresponding to sub-pixels of the same color. 39. The sub-pixel comprises sub-pixels of three colors, wherein first and second low-resistance conductors having different wiring resistances are alternately arranged in the horizontal scanning direction, and the first and second low-resistance conductors are arranged in the horizontal scanning direction. 27. The display device according to claim 26, wherein sub-pixels of the first to third colors are repeatedly arranged. 40. The display device according to claim 39, wherein the first to third colors are red, green and blue. 41. The display device according to claim 26, further comprising a light source. 42. The display device according to claim 26, further comprising a signal source for generating an image signal to be supplied to the display device. 43. The display device according to claim 26, wherein the display device is a color display device, and the same low-resistance conductor is provided corresponding to sub-pixels of three colors. 44. The ratio of the values of the wiring resistance is the first and the second.
27. The display device according to claim 26, wherein the display device is set so as to be inversely proportional to the area ratio of the transparent conductive film. 45. The display device according to claim 26, wherein the pixel is a pixel whose display state is determined according to a wiring state of a chiral nematic liquid crystal or a chiral smectic liquid crystal.