JPH0750273B2 - Liquid crystal electro-optical device - Google Patents

Description

The present invention relates to a liquid crystal electro-optical device, and more particularly to a manufacturing method thereof.

[Outline of Invention]

In the liquid crystal electro-optical device, the present invention is a conductive film having an appropriate thickness that also serves as a gearing agent and an electrode, so that when two substrates are superposed, the thickness of the liquid crystal layer in a pixel portion becomes a desired thickness. Is provided on at least one of the substrates other than the pixel portion, the thickness of the conductive film can be increased to a thickness substantially equal to a desired liquid crystal layer thickness. Therefore, even if the desired liquid crystal layer thickness is thin, the wiring resistance reducing effect can be utilized to the maximum extent, and the step of spraying the gearing agent can be omitted.

[Prior art]

The structure of a conventional liquid crystal electro-optical device is such that a glass fiber, beads, a polymer film or the like as a gearing agent is sandwiched between two substrates.

[Problems to be solved by the invention]

However, in the above-mentioned conventional technique, the thickness of the liquid crystal layer is the sum of the diameter of the gearing agent and the thickness of the conductive film provided for reducing the wiring resistance. As an example, if the desired liquid crystal layer thickness is 5 μm,
For example, the diameter of the gearing agent may be 2 μm and the thickness of the conductive film may be 3 μm. The thickness of the conductive film may be sufficiently thick to reduce the wiring resistance.

By the way, the ferroelectric smectic liquid crystal has a memory effect, a sharp threshold characteristic, and
It exhibits excellent characteristics of high-speed response and has high potential as a material for liquid crystal electro-optical devices. The liquid crystal layer thickness at which these characteristics are expressed depends on the liquid crystal material, but it is desirable to be about 1.5 μm or less in order to obtain good characteristics. As the liquid crystal layer thickness increases, the memory effect and the threshold characteristic The steepness decreases. Further, the contrast ratio of the liquid crystal electro-optical device using the ferroelectric smectic liquid crystal is expressed by the formula (1).
It can be obtained from the transmitted light amount I between crossed Nicols, and when white light is used as the light source, Δn = 0.2
Then, the optimum liquid crystal layer thickness d is around 1.4 μm. ([Delta] n of the ferroelectric smectic liquid crystals that are currently used
The value of is around 0.2. ) I = I ₀ sin ² 4θ ・ sin ² (πdΔn / λ) (1) θ: angle between the molecular axis of liquid crystal and the polarizer Δn: birefringence d: liquid crystal layer thickness λ: wavelength of incident light I ₀ : Incident light quantity In addition, the frequency of the drive voltage waveform becomes higher as the cycle of switching the ON / OFF state of the liquid crystal electro-optical device becomes shorter, and if the wiring resistance and capacitance are high, the drive voltage waveform is distorted and driven. Can't do it. Therefore, when the desired thickness of the liquid crystal layer is 1 μm, the use of a gearing agent according to the conventional method causes the thickness of the conductive film to be several thousand Å, which reduces the effect of reducing the wiring resistance. .

Therefore, the present invention solves such a problem, and an object thereof is to make maximum use of the wiring resistance reduction effect of the conductive film even when the desired liquid crystal layer thickness is very thin, An object of the present invention is to provide a liquid crystal electro-optical device that does not need to disperse a gearing agent.

[Means for solving problems]

The liquid crystal electro-optical device of the present invention is a liquid crystal electro-optical device in which a liquid crystal is sandwiched between a pair of substrates having electrodes on the inner surfaces facing each other, and at least a portion of the one electrode which is not a pixel is electrically connected to the electrode It is characterized in that a conductive film, which is also electrically connected and also serves as a spacer for controlling the gap between the substrates, is formed.

〔Example〕

FIG. 1 shows the first embodiment. FIG. 1 (a) illustrates the present invention.
FIG. 1 is a plan view of a liquid crystal light shutter section when applied to a 1/2 duty liquid crystal printer head, and FIG. 1 (b) is a sectional view taken along line AA ′ of FIG. 1 (a). A scan electrode 11 and an insulating layer (SiO ₂ ) 14 are provided on a lower substrate 17, and an alignment treatment film 18 of PI, nylon, PVA or the like is provided on the scan electrode 11 and a rubbing treatment in one direction. Signal electrodes on the upper substrate 16
12 is provided, and a conductive film 15 is provided in a portion other than the pixel 13. 20 is a polarizing plate. In FIG. 1 (a), the thickness of the conductive film of the liquid crystal introduction portion 21 which is double shaded is thinner than the desired liquid crystal layer thickness, and the liquid crystal 19 passes through that portion.
Enters the portion of pixel 13.

A liquid crystal printer head having the structure shown in FIG. 1 was prepared by using ITO and nickel (thickness: 0.95 μm) as a transparent electrode and a conductive film, respectively. la ＝ 180μm, lb ＝ 220μm, lc ＝
MBRA-8, which is a liquid crystal material with a thickness of 80 μm, is sealed by the vacuum sealing method, and the liquid crystal layer thickness calculated from the birefringence of the liquid crystal is 1.01 ±
A liquid crystal printer head having a uniform liquid crystal layer thickness of 0.04 μm was obtained.

For reference, FIG. 2 shows a cross-sectional view of a conventional liquid crystal printer head. Since the diameter of the gearing agent (bead) 22 is small, about 0.8 μm, the thickness of the highly conductive film is about 0.2 μm if the desired liquid crystal layer thickness is 1 μm.
Its thickness is about 1/5 of the thickness in the first embodiment,
The wiring resistance reduction effect is diminished.

A second embodiment is shown in FIG. In this embodiment, the lower substrate 17
A nickel film is provided as a conductive film 15 on the upper scanning electrode 11 and SiO ₂ 14 is provided for insulation. The thicknesses l ₃ and l ₄ of the nickel films on the scanning electrode and the signal electrode are both 1.5 μm, and the thicknesses of SiO ₂ and nylon are 1000 respectively.
Å, 800Å, la ＝ 180μm, lb ＝ 220μm, lc ＝ 40μm, M
A liquid crystal printer head was prepared using BRA-8.
The liquid crystal layer thickness in this example was 3.10 ± 0.03 μm.

FIG. 4 shows a third embodiment. Here, an application example to a matrix type liquid crystal display is shown. The conductive film 15 is provided at the end of the stripe-shaped signal electrode 12, and is shown in FIG.
The circular portion with heavy diagonal lines has a scalloped shape as shown in FIG. 4 (b). Using copper as the conductive film, la
= 430 μm, lb = 70 μm, lc = 30 μm, l ₅ = 0.5 μm, l ₆ = 70 μm,
A 100 × 100 matrix liquid crystal display was prepared using MBRA-8 with lc = 30 μm, l ₅ = 0.9 μm, l ₆ = 0.6 μm. The liquid crystal layer thickness was 1.06 ± 0.03 μm.

The present invention can be applied to liquid crystal electro-optical devices other than the liquid crystal printer head and the matrix type liquid crystal display, and the liquid crystal material is not limited to the ferroelectric smectic liquid crystal and the liquid crystal layer thickness is not limited.

〔The invention's effect〕

With the above configuration, the following effects can be obtained.

Since the conductive film is formed along at least one of the electrodes, the wiring resistance of the electrode is reduced. In addition, the gap between the substrates can be controlled by the conductive film.

Since the wiring resistance can be reduced, the delay of the voltage pulse is reduced. Therefore, high quality display can be obtained.

[Brief description of drawings]

FIG. 1 (a) is a plan view of the liquid crystal printer head in the first embodiment, FIG. 1 (b) is a sectional view taken along line AA 'of FIG. 1 (a), and FIG. 2 is a sectional view showing a conventional technique. FIG. 3 is a sectional view of the liquid crystal printer head in the second embodiment,
FIG. 4 (a) is a plan view of the liquid crystal display in the third embodiment, and FIG. 4 (b) is a sectional view taken along the line AA 'in FIG. 4 (a). 11 …… Scan electrode 12 …… Signal electrode 13 …… Pixel 14 …… Insulating layer 15 …… Conductive film 16 …… Upper substrate 17 …… Lower substrate 18 …… Alignment film 19 …… Liquid crystal 20 …… Polarization Plate 21 …… Liquid crystal introduction part 22 …… Gearing agent

Claims (1)

[Claims] 1. A liquid crystal electro-optical device comprising a pair of substrates having electrodes on opposite inner surfaces and a liquid crystal sandwiched between the substrates, the liquid crystal electro-optical device being electrically connected to at least a portion of the one electrode which is not a pixel, A liquid crystal electro-optical device characterized in that a conductive film which also functions as a spacer for controlling a gap between the substrates is formed.