JPH02264221A - Liquid crystal display device and production thereof - Google Patents

Abstract

PURPOSE:To allow a uniform display without having various densities by connecting ITO display electrodes through apertures of color filters to comb- shaped metallic layers (auxiliary electrodes) provided in the parts positioned in the inter-electrode spaces under the apertures. CONSTITUTION:The color filter layers 3 and the comb-shaped auxiliary electrodes 2 are so registered that the comb tooth parts 10 of the auxiliary electrodes 2 are exposed by connecting holes 9 of the color filter layers 3. A transparent conductive film (ITO) consisting of indium oxide contg. tin is formed on the color filter layers 3 and is patterned to a band shape, by which scanning electrodes 4 are provided. The scanning electrodes 4 intersect orthogonally with the stripe-shaped color filter layers 3 and the respective inter-electrode spaces are positioned in the long side parts of the auxiliary electrodes 2. The scanning electrodes 4 are, therefore, connected through the connecting holes 9 (apertures) of the color filter layers 3 to the auxiliary electrodes 2 and act as the scanning electrodes of low electric resistances. The uniform display free from unequal displays is attained in this way even at the time of the high time divided driving.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a display device that utilizes electro-optical changes in liquid crystal, and in particular to a liquid crystal display device and its use for improving display quality during high time division driving. This relates to a manufacturing method.

Background of the Invention In recent years, display devices have been required not only to be thinner, lighter, and consume less power, but also to have larger display capacities, uniform and superior display quality, and even larger screens. Became.

In response to these demands, liquid crystals have attracted particular attention as the most excellent display material, and are currently the mainstream of flat panel display devices.

In order to display a lot of information, a lot of pixels are required. For this reason, the mainstream display format is a matrix type that operates by high time division driving.

In order to obtain a display with high contrast and good visibility using high time-division driving, the electro-optic characteristics of the liquid crystal panel, that is, the voltage-luminance characteristics (dark value characteristics), must be steep, and the brightness level when the OFF voltage is applied must be high. It is important that it is sufficiently small.

In order to meet these demands, we created a panel structure in which the twist angle of the liquid crystal molecules was further expanded from the conventional 90 degrees, thereby significantly improving the dark value characteristics.At the same time, we created a two-layer structure for the liquid crystal layer to reduce the amount of light. Measures have been taken, such as a configuration that compensates for the optical rotation dispersion phenomenon.

Through these various measures, the display capacity has been dramatically expanded as the display contrast has been improved. However, in order to obtain a high-definition display on a large screen, the display electrode width must be formed extremely narrow. Therefore, the shape of the display electrode becomes extremely thin and long.

Hereinafter, a conventional liquid crystal display device will be explained with reference to the drawings.

FIG. 3 is a cross-sectional view schematically showing the structure of a conventional liquid crystal display device. In FIG. 3, reference numerals 1 and 6 indicate transparent substrates, and a color filter layer 3 is provided on the substrate 1, and a scanning electrode 4 is further provided on top of the color filter layer 3. Furthermore, a signal electrode 7 is provided on the substrate 6 with an opening. Further, a liquid crystal layer 5 is formed on the scanning electrode 4 and the signal electrode 7, respectively. The substrate 1.6 has scanning electrodes 4 and signal electrodes 7 combined so as to be orthogonal to each other.
The gap between the substrates 1.degree.6 is filled with liquid crystal material 8 using a sealed material 13.

Usually, the display electrode is formed by photoetching a transparent conductive film of indium oxide (hereinafter referred to as ITO) containing tin. Generally, the conductivity of an ITO film improves as the film becomes thicker, but the thicker the film, the lower the transmittance. For this reason, a film with a thickness of about 2,500 layers is used.
The sheet resistance value in this case is approximately 10Ω/C.

Here, this ITO film has a line width of 0.2+n+n and a line length of 25
When patterned as a display electrode of 0[111+1, the resistance value in the longitudinal direction is 12.5Ω: Therefore, when power is supplied from one end of the electrode, a voltage drop occurs, and the display changes accordingly. A gradient of .

Conventionally, in order to solve this problem, an auxiliary electrode has been formed in the long direction on the thinned ITO electrode. (For example, Nikkei Electronics, February 16, 1981 issue, p. 148) Problems to be Solved by the Invention In the conventional configuration in which an even thinner metal auxiliary electrode is provided on an ITO electrode that is subdivided into strips, the following is described. There was a fatal problem regarding the display performance of liquid crystal panels.

In other words, in liquid crystal display panels using polarizing plates, the light utilization rate is currently less than 5%, so in order to obtain a bright display, it is necessary to minimize the space between the electrodes and increase the aperture ratio. is important.

However, in the conventional configuration, the auxiliary electrode provided on the ITO electrode is made of Cr-Au and Cr.
- A metal with low electrical resistance such as A1 is used. Therefore, no light passes through this auxiliary electrode portion, resulting in a decrease in aperture ratio. Therefore, there is a drawback that the efficiency of light for 4++ is poor and the display is dark.

The present invention aims at lowering the resistance of display electrodes without reducing the aperture ratio, and also blocks unnecessary light leaking from the space between the electrodes, making it possible to significantly improve display characteristics. The purpose is to provide a liquid crystal display device.

Means for Solving the Problems In order to achieve the above objects, the liquid crystal display device of the present invention includes:
A plurality of comb-shaped auxiliary electrodes are provided on the first substrate, and then,
On top of this, a striped color filter layer of multiple colors is provided with an opening so as to expose a part of the auxiliary electrode, and on top of that, a plurality of transparent scanning electrodes are provided.
The scanning electrode and the auxiliary electrode are arranged perpendicularly to the stripe direction of the color filter layer, and are configured to electrically connect the scanning electrode and the auxiliary electrode through the opening of the color filter layer.

Function In the above configuration, each ITO display electrode is connected to the comb-shaped metal layer (auxiliary electrode) provided in the inter-electrode space below through the opening of the color filter, so that the ITO display electrode is connected in its length direction. electrical resistance is kept extremely low.

As a result, even when power is supplied from one direction, there is no voltage drop in the length direction, and therefore a homogeneous display without shading is possible. Furthermore, since this auxiliary electrode is not formed on the display electrode, the aperture ratio is not reduced, resulting in a bright and easy-to-see display.

Furthermore, since the metal layer (auxiliary electrode) is disposed in the space between each display electrode via a color filter, unnecessary light leaking from this portion is blocked. This effect dramatically increases the contrast of the display, making it possible to display with excellent visibility.

EXAMPLE Hereinafter, a liquid crystal display device according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing the structure of a liquid crystal display device of the present invention, and FIG. 2 is a plan view illustrating the main parts of the present invention along the manufacturing process.

A metal layer is formed on a transparent substrate 1 and patterned to provide a comb-shaped auxiliary electrode 2 as shown in FIG. 2(a). The metal layers used here include Ni, Cr, A
I, Au, etc. are suitable, but Cr-Au or Cr
A two-layer structure such as -A 1 is preferable because it has low electrical resistance and strong adhesive strength with the underlying substrate. Next, a color filter layer 3 as shown in FIG. 2(b) is formed thereon. The color filter layer 3 has R, G, B
, in the form of stripes, and a part of each overlapping part is a connection hole 9 (opening) so that the auxiliary electrode is exposed.
is provided. As a method for forming the color filter layer 3, a printing method, a dyeing method using a photolithography method, or the like is applied. Color filter layer 3 and auxiliary electrode 2
As shown in FIG. 2(C), the comb teeth portions 10 of the auxiliary electrode 3 are combined so that they are exposed through the connection holes 9 of the color filter layer 3. Thereafter, a transparent conductive film of indium oxide containing tin (hereinafter referred to as ITO) is formed on this color filter layer 3, and this is patterned into a strip shape to form scanning electrodes 4 as shown in FIG. 2(d). . Here, the scanning electrodes 4 are arranged to be perpendicular to the striped color filter layer 3, and the spaces between the respective electrodes are located on the long sides of the auxiliary electrodes 2. As a result, the scanning electrode 4. is connected to the auxiliary electrode 2 through the connection hole 9 (opening) of the color filter layer 3, and becomes a scanning electrode with extremely low electrical resistance. Further, each intersection of the scanning electrode group and the striped color filter becomes a pixel portion 12.

The substrate 1 provided with the respective layers in this manner is further provided with a liquid crystal alignment layer 5 on the scanning electrodes.

A transparent conductive layer of ITO is formed on the other transparent substrate 6, and a band-shaped signal electrode group 7 is provided by patterning this, and then a liquid crystal alignment layer 5 similar to that described above is provided thereon.

The substrates 1.6 are then assembled in such a way that the respective electrode groups 4, 7 are orthogonal to each other. At this time, the signal electrode 7 is aligned with the pixel portion 12 of the color filter 3. Thereafter, the liquid crystal material 8 is filled into the gap between the substrates 1.6 using the sealed material 13 to complete the liquid crystal cell.

In such a liquid crystal cell, since the electrical resistance of the scanning electrode is extremely low, power needs to be supplied only from one side, and a color display with high contrast and excellent color reproducibility can be obtained even during high time division driving.

As described in detail, according to the liquid crystal display device of the present invention, since the electrical resistance of the display electrodes is extremely low, uniform display without display unevenness is possible even during high time division driving. In addition, since the auxiliary electrode is located between each pixel, it does not reduce the aperture ratio, and it also blocks unnecessary light leaking from areas other than the pixels, resulting in bright, high-contrast, high-quality images with excellent color reproducibility. Color display can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing the configuration of an embodiment of the liquid crystal display device of the present invention, FIG. 2 is a plan view illustrating the manufacturing process of the main parts of the present invention, and FIG. 3 is a conventional liquid crystal display. FIG. 2 is a cross-sectional view schematically showing the configuration of the device. 1.6...Transparent substrate, 2...Auxiliary electric bridge, 3...Color filter layer, 4...
Scanning electrode, 5...Liquid crystal alignment layer, 7...
Signal electrode, 8...Liquid crystal material, 9...Connection hole, 10...Comb-shaped portion, 11...End connection portion, 12... ...Pixel section, 13...Sealant. Name of agent: Patent attorney Shigetaka Awano

Claims (2)

[Claims] (1) A pair of transparent substrates sandwiching a liquid crystal layer, the first substrate is provided with a plurality of color filter layers and a transparent scanning electrode, the second substrate is provided with a transparent signal electrode, and the scanning electrode and the signal A liquid crystal display device in which a plurality of comb-shaped auxiliary electrodes are provided on the first substrate, and one of the auxiliary electrodes is disposed on the first substrate. The color filter layer is provided in the form of a stripe of a plurality of colors with openings so as to expose the color filter layer, and a plurality of transparent scan electrodes are arranged on the color filter layer so as to be orthogonal to the stripe direction of the color filter layer. established,
A liquid crystal display device, wherein the scanning electrode and the auxiliary electrode are electrically connected through the opening of the color filter layer. (2) Forming a plurality of comb-shaped auxiliary electrodes on a transparent first substrate, and then forming a striped color filter layer with openings on the auxiliary electrodes in the comb-like shape of the auxiliary electrodes. a step of forming a plurality of transparent scanning electrodes corresponding to the auxiliary electrodes so as to cover the auxiliary electrodes and the color filter layer; a step of forming a plurality of signal electrodes, and a step of bonding the first substrate and the second substrate facing each other with a predetermined gap maintained so that the scanning electrodes and the signal electrodes are perpendicular to each other. and filling a gap between the first substrate and the second substrate with a liquid crystal material.