JPH02287433A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve an imperfect display caused by the deviation of a voltage drop by the distance between a driving IC chip and a transparent electrode by forming a wiring made of a low resistive metal between the transparent electrode and the driving IC chip and also disposing a protective film made of the same material as an oriented film on the wiring in a sealing member. CONSTITUTION:The metallic wiring is extended from the outputting terminal of the driving IC chip 11a on a substrate 1a respectively corresponding to the transparent electrode 2a so as to come in contact with the transparent electrode 2a from the metallic wiring 12 at a part to be attached in the sealing part 6. And also the metallic wiring 12 electrically connected with the outputting terminal of the driving IC chip 11b is covered with the protective film 15 in the inside area of the sealing part 6. The protective film 15 is formed of an organic material such as a polyimide., etc., or formed by the same material and the same stage as the oriented film 3a such as a silicon dioxide film, etc. Thus, the deviation of the voltage drop can be satisfactorily reduced and the good display can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a matrix display liquid crystal display device.

[Conventional technology]

In the conventional liquid crystal display device, as shown in FIG. 4, a liquid crystal 44 is sealed between two transparent substrates 41a and 41b on which transparent electrodes 42a and 42b and alignment films 43a and 43b are attached, and further, Polarizing plates 45a and 45b are arranged on the outer surfaces of the two transparent substrates 41a and 41b, respectively. The liquid crystal display device configured in this way has transparent electrodes 4
By applying an electric field to the liquid crystal 44 through 2a and 42b, the alignment of liquid crystal molecules defined by the alignment films 43a and 43b changes, allowing only a predetermined light beam from the outside such as the light emitting means 49 to pass through or be blocked. A predetermined display was performed. A transparent electrode 42a is provided in the display area of the transparent substrate 41a.
is formed in the X direction, and a transparent electrode 42b is formed on the transparent substrate 41b in the Y direction, and a dot matrix is formed by the intersection of each transparent electrode 42a, 42b.

A predetermined electric field is applied to the predetermined transparent electrodes 42a and 42b by multiplex driving.

For example, when the display area becomes high duty such as 640 x 400 dots, the voltage difference that determines whether or not the alignment of liquid crystal molecules is changed becomes small.

Multiplex driving uses a driving circuit (driving 1c chip) to accurately control the potentials to be applied to multiple points of intersection (dots) with the transparent electrodes 42a, 42b.

As shown in FIG. 5, these driving IC chips 46a, 46b are provided with a driving voltage from an external control circuit (not shown), a simplified data signal input wiring pattern, and a substrate mounting of the driving IC chips 46a, 46b. In view of simplification of work, it is arranged only on one of the substrates 41a (the substrate on the side having the signal side electrode). And driving IC chip 46
The predetermined electric field signals derived from the output terminals a and 46b are:
Each one is supplied to one transparent electrode 42a, 42b.

At this time, the transparent electrode 42a of the substrate 41a on which the driving ICC chips 6a and 46b are arranged and the driving IC chip 46a are extremely close to each other, and each driving IC chip 46
There is little difference in the distance from the output terminal a to the transparent electrode 42a, and the effect of voltage drop due to the difference in distance can be ignored.

However, in order to supply a predetermined electric field signal from the driving ICC chip 6b to the transparent electrode 42b of the substrate 4b, it is necessary to avoid the display area and reach the transition point 47 where the signal is conducted from the substrate 41a to the base W4lb. At least 4 wiring lines
8 had to be set. That is, the transparent electrode 42b
The distance of the wiring 48 between the end of the display area and the driving ICC chip 6b varies depending on each transparent electrode 42b. For example, the width of the display area in the scanning direction is 10
If there is a distance of 0m, there will simply be a difference of about 100rui between the shortest route and the longest route. As a result, a slight deviation occurs in the potential applied to each transparent electrode 42b, making it difficult to display uniformly.

Furthermore, in a high-duty liquid crystal display device with a display area of 640 x 400 dots, the voltage difference that determines whether or not the alignment of liquid crystal molecules is changed is small, so the deviation in potential becomes even more noticeable.

As a method to prevent this, as shown in Fig. 5, the line width of the lead-out wiring 48 is changed, the deviation in voltage drop due to distance is corrected by the line width, and the voltage drop is approximately uniform as a whole. It is possible that

However, in the method based on line width control, l/100
It is possible to make the voltage drop uniform in a matrix display with a duty ratio, but as the distance between the transparent electrodes 42a and 42b becomes narrower due to larger screens, higher density, and colorization, the lead-out wiring 48 This made it difficult to control the wire width due to the design and etching process, so it was not a complete solution.

[Object of the present invention]

The present invention was devised in view of the above problems, and
The purpose of this technology is to significantly improve display defects caused by deviations in voltage drop due to the distance between the driving IC chip and the transparent electrode, and to produce liquid crystal displays with stable manufacturing yields, even in the case of larger screens and higher densities where the electrode line spacing is narrower. It provides equipment.

[Specific Means for Solving the Problem] According to the present invention, in order to solve the above-mentioned problem, a seal is provided between two transparent substrates in which a transparent electrode and an alignment film are formed in the displayable area. In a liquid crystal display device in which a liquid crystal is sealed in a space surrounded by a material and a signal from a driving IC chip on the substrate is applied to the transparent electrode, there is a space between the transparent electrode and the driving IC chip. A liquid crystal display device is provided in which a low-resistance metal wiring is formed and a retaining MWJ made of the same material as an alignment film is provided on the wiring within a sealing material.

〔Example〕

Hereinafter, the liquid crystal display device of the present invention will be explained in detail based on the drawings.

FIG. 1 is a plan view showing the structure of a liquid crystal display device according to the present invention, and FIG. 2 is a cross-sectional view taken along the line X--X in FIG.

The liquid crystal display device according to the present invention includes transparent electrodes 2a, 2b and orientation El! two transparent substrates 1a to which 3a and 3b are attached;
A liquid crystal material 4 is sandwiched between the two transparent substrates 1a and 1b, and polarizing plates 5a and 5b are arranged on the outer surfaces of the two transparent substrates 1a and 1b, respectively.

The two transparent substrates 1a and 1b are made of glass or the like, and at least the display portion includes transparent electrodes 2a made of metal oxides such as indium tin oxide, indium oxide, and tin oxide.
2b is formed, and a driving IC chip lla, 11b for giving a predetermined signal to the electrodes 2a, 2b and/or a routing metal wiring 12 made of aluminum, chrome, etc. are formed in the wiring part C on the outer periphery of the display area. There is.

The transparent electrodes 2a and 2b are formed on the two transparent substrates 1a and 1b, in a portion corresponding to the display area, and the transparent electrodes 2a and 2b are
, a plurality of transparent electrodes 2a (signal side electrodes) are arranged in a certain direction,
For example, it is formed in the X direction, and on the other transparent substrate ib, it is formed in a direction perpendicular to the transparent electrode 2a of one transparent substrate vila, for example, in the Y direction.

The alignment films 3a and 3b are made of an organic material such as polyimide or a silicon dioxide film deposited by oblique vapor deposition.
They are formed on transparent transparent electrodes 2a and 2b corresponding to the display area, respectively. Further, the alignment films 3a and 3b are rubbed in a certain direction as necessary to control the molecular alignment of the liquid crystal 4.

The liquid crystal 4 includes a twisted nematic liquid crystal base material exhibiting positive dielectric anisotropy mixed with a chiral substance that defines the twist direction and twist amount. The liquid crystal 4 is sealed between the two transparent substrates 1a and lb described above and the surrounding sealing material 6.

The layer thickness d of the liquid crystal 4 is 10 μl or less, for example, 7.6 μl,
Due to the rubbing direction of the alignment films 3a and 3b mentioned above, the long axis direction of the liquid crystal molecules adjacent to the transparent substrates 1a and 1b is 180 degrees.
~270°, e.g. 250° twisted. Further, the product (retardation a) of the refractive index Δn determined by the liquid crystal material and the thickness d of the liquid crystal layer 4 is 0.4 to 0.96, for example, 0.43.
is set to .

The polarizing plates 5a and 5b are attached to the outer surfaces of the substrates 1a and 1b so that the polarization axis and the long axis direction of liquid crystal molecules adjacent to the respective substrates 1a and 1b form a predetermined angle.

Note that inside the liquid crystal 4 and the surrounding sealing material 6, there are substrates la and 1.
In order to keep the layer thickness d of the liquid crystal 4 constant over the entire area b, a gap material 7 such as glass fiber or resin pearls is dispersed.

The electric field applied to the liquid crystal 4 is supplied by driving IC chips lla and llb via transparent electrodes 2a and 2b.

The driving ICC chips la and llb are arranged on one substrate la, and are supplied with supply voltage, display data, clock signals, synchronization signals, etc. from an external signal generation circuit (not shown), and are driven by multiplex drive. A predetermined voltage is supplied to the selected transparent electrodes 2a, 2b.

The routing metal wiring 12 is connected to the above-mentioned driving IC chip ll.
It is formed in order to apply the voltage output from the terminals a and llb to the transparent electrodes 2a and 2b in the display area. Specifically, it is made of a low-resistance metal, aluminum, chromium, etc., and is formed in the wiring portion C of one substrate 1a so as to connect the output terminals of the driving IC chips 11a and llb to each transparent electrode 2a and 2b. ing. Note that the voltage is supplied to the other substrate 1b by extending the metal wiring 12 of the substrate 1a to the vicinity of the end of the transparent electrode 2b, and applying the voltage to the dot-shaped transition point 1 of the silver base plate or the like.
3 is applied from the metal wiring 12 of the substrate 1a to the transparent electrode 2b on the substrate lb side.

In the above liquid crystal display device, for example, the light emitting means 14 is arranged on the side of the polarizing plate 5b, and when no electric field is applied to the liquid crystal 4, the light from the light emitting body 14 is linearly polarized by the polarizing plate 5b and when it passes through the liquid crystal 4. , linearly polarized light is applied to liquid crystal material 1
It becomes elliptically polarized light depending on the angle. Then, a component of light in a predetermined direction is extracted as polarized light i5a. Depending on the relationship between this retardation and a component in a predetermined direction on the polarizing plate, a blue mode, yellow mode, or black and white mode can be set. When an electric field is applied to the liquid crystal, the light from the light emitter is linearly polarized by the polarizing plate 5b, and even if it passes through the liquid crystal layer 4, it does not become elliptically polarized light, and only components in a predetermined direction are extracted by the polarizing plate 5a. .

FIG. 3 is a partially enlarged view of the present invention.

They extend from the drive IC chip lla output terminals of the substrate 1a so as to correspond to the transparent electrodes 2a, respectively, and are contacted from the metal wiring 12 to the transparent electrodes 2a at the portion where the seal portion 6 is attached. In addition, the transparent electrode 2
A number of metal wires 12 corresponding to b are extended, avoid the display area, go beyond the seal portion 6, and extend to a transition point 13 formed at the end of the transparent electrode 2b.

The metal wiring 12 is formed of a single layer or a stack of low-resistance materials such as aluminum, chromium, and nickel with a thickness of 0.5 to 2.0 μm, so that the transparent electrode near the driving IC chip llb The difference in voltage drop due to the difference in the routing distance between transparent electrode 2b and transparent electrode 2b on the far side can be substantially ignored. Further, the metal wiring 12 electrically connected to the output terminal of the driving IC chip llb is covered with a protection M15 in the inner region of the seal portion 6.

The FI-retaining film 15 is formed of the same material and in the same process as the alignment film 3a, such as an organic material such as polyimide or a silicon dioxide film. By forming the protective film 15, the liquid crystal 4 and the metal wiring 12 do not come into direct contact with each other, and the metal wiring 12 is completely prevented from being corroded by moisture in the liquid crystal.

The protective fill 15 is formed continuously with the alignment film 3a, and even if further alignment treatment is performed, it still functions well as the protective film 15, but it may be formed separately from the alignment film 3a.

Note that it is possible to increase the adhesive strength with the substrates 1a and lb by widening the width of the seal portion 6 at the intersection between the metal wiring 12 electrically connected to the output terminal of the driving IC chip lb and the seal portion 6. is important.

Next, to explain the method of mounting the metal wiring 12 and the transparent electrode 2a, first, the transparent electrode 2 is placed on the entire surface of the transparent substrate 1a.
An indium-tin alloy is deposited to a thickness of 700 to 2,000 layers by sputtering or the like, and a low-resistance metal film such as aluminum, chromium, or nickel, which becomes the low-resistance layer of the metal wiring 12, is formed in a single layer or in a laminated manner. Deposit. Next, using photolithography technology, the transparent electrode 1a and the metal wiring 12 are patterned, and areas other than the display area are masked.
Only the low resistance metal film in the display area is selectively removed. Thereafter, by heating and oxidizing, the indium-tin alloy exposed in the display area is transformed into a transparent conductive film of indium-tin oxide.

As described above, since the metal wiring 12 with low resistance is formed in a simultaneous pattern in the process of forming the transparent electrode 2a, the metal wiring 12 and the transparent electrode 2a are integrated in a simple process, and the connection is ensured, and the transition point The difference in voltage drop due to the routing distance up to 13 is improved.

It should be noted that if the entire metal wiring 12 and driving IC chips lla, llb outside the sealing material 6 are covered with a protective resin such as silicone, this will be effective against corrosion due to atmospheric moisture.

Further, as shown in FIG. 2, the metal wiring 12 is immediately connected to the signal terminal 17 connected to the external circuit via the liquid crystal 4 inside the sealing material 6, and the driving IC chips lla, flb
It may also be formed so as to be routed to the side. Thereby, the substrate 1a can be minimized, and the occupation rate of the display area with respect to the substrate 1a is improved. In this case as well, metal wiring 1
It is important to form the protective film 15 so that the 2° does not come into contact with the liquid crystal 4. More preferably, the metal wiring 1 such as the ground wiring to the driving IC chips Ila and flb or the wiring for the driving voltage is provided in the portion intersecting with the sealing material 6.
It is possible to increase the strength of the bond to the transparent substrates 1a and 1b by dividing the wiring which should be widened into two and placing the sealing material 6 between the wirings.

Although the above-mentioned embodiments have been described using a transmissive liquid crystal display device, a wide variety of devices such as a reflective type liquid crystal display device and a stacked type liquid crystal display device having a plurality of liquid crystal layers can be used.

[Effects of the present invention]

As described above, according to the liquid crystal display device of the present invention, the deviation of the voltage drop of the voltage signal from the driving IC chip to the transparent electrode can be sufficiently reduced without performing line width processing in the routing portion. This enables good display.

In addition, even if the metal layer of the metal wiring, such as aluminum, nickel, or chromium, extends inside the sealing material that seals the liquid crystal, the metal wiring is covered with a protective film that is formed in the same process as the alignment film. Because of this, there is no corrosion and a good display can be achieved over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the structure of a liquid crystal display device according to the present invention. FIG. 2 is a sectional view taken along the line X--X in FIG. 1. FIG. 3 is a partially enlarged plan view of the liquid crystal display device of the present invention. FIG. 4 is a sectional view showing the structure of a conventional liquid crystal display device, and FIG. 5 is a partially enlarged plan view of the conventional liquid crystal display device. la, lb, 41a, 41b...transparent substrates 2a, 2
b, 42a, 42b---Transparent electrode 3a, 3b, 43
a, 43b...Alignment film 4.44. ......Liquid crystal layers 5a, 5b, 45a, 45b...-polarizing plate 11a,
llb...Drive IC chip 12...
...Metal wiring 15 ...Protective film

Claims (1)

[Claims] A liquid crystal is sealed in a space surrounded by a sealing material and between two transparent substrates in which a transparent electrode and an alignment film are formed in a displayable area,
In a liquid crystal display device in which a signal from a driving IC chip on the substrate is applied to the transparent electrode, a low-resistance metal wiring is formed between the transparent electrode and the driving IC chip, and a metal wiring is formed in the sealing material. A liquid crystal display device characterized in that a protective film made of the same material as the alignment film is provided on the wiring.