JPS60191224A - Electrooptic device - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal display element having high productivity and good contrast by providing an electrode on all of the surface of one substrate and orienting a liquid crystal vertically in areas of parts, which are not related to display patterns, and parts of the substrate facing these parts and orienting the liquid crystal horizontally in the other areas. CONSTITUTION:A common electrode 3 consisting of a transparent conductive film is provided on all of the surface of a lower substrate 2, and a background electrode 4 and segment electrodes 5 consisting of transparent conductive films are provided on all of the surface of an upper substrate 1, gap parts 8 having no electrodes are formed between electrodes 4 and 5. In an execution mode shown in the figure, an area E corresponding to a leading-around line part which is not related to display patterns is formed, and an area F corresponding to a part, to which a voltage is not applied, is formed in the electrode 5. The liquid crystal is oriented vertically in areas C and F having no electrodes in the display region and the area corresponding to the leading-around line part, which is not related to display patterns, in segment electrodes, and the liquid crystal is orientated horizontally in the other areas A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electro-optical device, particularly a dust-host type liquid crystal display device, and more particularly to a phase change type liquid crystal display device in which a dichroic dye is dissolved.

Recently, research and development on a phase transition method has been carried out as a dust-host type liquid crystal display device. This method has the advantage of a bright display surface because it does not require a polarizing plate to increase contrast. , it was limited to negative displays that displayed colorless and lean characters on colored backgrounds.

For this reason, in order to maintain the brightness of the display surface of the phase change method, and to make the display a positive display that displays a colored pattern, the gap between the pair of electrode substrates and the alignment treated surface is changed to four turns of the actual display surface. In the background area, liquid crystal molecules and dichroic dyes are substantially homeotropically aligned, and in the display area, liquid crystal molecules are aligned vertically. It has been reported that dichroic dyes are oriented non-homeotropically (Grandshuan).

In this method, the display area is colored when no voltage is applied, and when a voltage is applied, the display area is discolored and shows almost the same transmittance as the background area, giving an apparent positive display. It is something to do.

However, the transmittance of the display part and the transmittance of the background part are
In order to achieve the same value, the cell spacing in the display area, the cell spacing in the background area, and the helical pitch due to the addition of an optically active agent must be designed very strictly.

Furthermore, if the cell spacing becomes thicker than a predetermined value, the background part will not be substantially homeotropically oriented, but will be colored due to Grandshuan orientation, so the cell spacing ff1
The disadvantage is that it becomes even more difficult to control LJ.

Another method is to provide electrodes in the background area in addition to the display electrodes (segment electrodes, common electrodes), and apply voltage to the background area and non-display areas of the display area during use to transfer the liquid crystal and dye to the substrate. A method of standing vertically has also been reported.

FIG. 1 shows a liquid crystal display device that performs display using the method described above, and will be described below with reference to FIG.

In FIG. 1, 1 is an upper substrate and 2 is a lower substrate. The lower substrate 2 is provided with a common electrode 3 made of a transparent conductive film, and the upper substrate 1 is provided with a background electrode 4 made of a transparent conductive film and segments. An electrode 5 is provided.

Between the upper and lower substrates 1.2 is a liquid crystal with positive dielectric anisotropy (
A layer of a mixture of a Np liquid crystal (Np liquid crystal) 6, a dichroic dye 7, and an optically active substance (not shown) is provided.

An opening 8 is provided between the background electrode 4 and the segment electrode 5.
is formed. In the figure, 9, 10.11 are switches,
12 indicates a power source.

In this liquid crystal display device, when a voltage axis is applied, the entire surface is colored with the color of the dichroic dye 7 in the Glanzyuan orientation.

Now, when the switches 9 and 11 are turned on and the switch 1o is turned off, the area A corresponding to the background electrode 4 is decolored, and the display area B corresponding to the segment electrode 5 and the area C corresponding to the interval part 8 are colored. To erase the color of the display area B, it is sufficient to turn on the switch 1o.

However, in this structure, since no voltage is applied to the region C corresponding to the space 8 between the segment electrode and the background electrode, the region C is always colored.

For this reason, it is necessary to make the spacing part 8 as narrow as possible, but due to the complexity of the photolithography process and the decrease in yield due to short circuits, it is currently necessary to make the spacing part 8 as narrow as possible.
The limit is about 30 μm.

FIG. 2 shows an example of a display iR turn formed on the upper substrate 1 of a conventional liquid crystal display device. In the figure, 4 indicates a background electrode, 5 indicates a display electrode, that is, a segment electrode, and 8 indicates a spacing section.

When this liquid crystal display device has a counter electrode, when the background electrode 4 is turned ON and the segment electrode 5 is turned OFF, the area indicated by D in the figure is decolored, and the area indicated by E is colored.
Be unified.

In addition, if there is no counter electrode, the area and E will always be in a colored state, which will deteriorate the quality of the characters and create significant restrictions on the shape of the characters.

As a countermeasure for this, it becomes less noticeable to some extent by narrowing the line width of the area and E, but considering the voltage drop caused by narrowing the line width, it is estimated that 30 μm
A certain amount of line width is required, and the problem has not been solved yet.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and at the same time provide a liquid crystal display element with low productivity and contrast.

An electro-optical device according to the present invention includes a layer having a mixture of a dichroic dye, a nematic liquid crystal having positive dielectric anisotropy, and an optically active substance arranged in a gap formed by a substrate having a pair of electrodes. In the device, electrodes are provided on one substrate over substantially the entire surface of the display section, except for the non-electrode contour section where the display and 1,000 turns are formed, and the non-electrode section within the display section and the segment electrode or the common electrode are provided on one substrate. It is characterized in that the area between the bent part that is involved in the display shape and the substrate facing it is vertically aligned, and the other area is horizontally aligned.

3 and 4 show a liquid crystal display device according to one embodiment of the present invention. In the figure, the same parts as those shown in FIGS. 1 and 2 are indicated by the same reference numerals.

As shown in the figure, in the device of the present invention, the lower substrate 2 is provided with a common electrode 3 made of a transparent conductive film over its entire surface, and the upper substrate 1 is provided with a transparent conductive film over substantially its entire surface. A background electrode 4 and a segment electrode 5 consisting of a membrane are provided. Between the background electrode 4 and the segment electrode 5, a gap 8 without an electrode is formed.

In the embodiment shown in the figure, a region E is formed corresponding to a routing line portion that is not involved in the display shape.

Furthermore, a region F corresponding to a portion to which no voltage is applied is formed within the segment electrode 5.

The present invention is arranged perpendicularly to regions C and Fl in the above-mentioned display area where there are no electrodes, and regions corresponding to lead-out lines that are not involved in the display shape in the segment electrodes, and other regions A.
, B are horizontally aligned.

Therefore, in the vertical alignment region, the liquid crystal molecules 6 and the dichroic dye 7 are homeotropically aligned, almost perpendicular to the substrate, so that no coloring by the dye 7 occurs, and no stain pressure is applied to the region C. , F, and the routing line portions that are not involved in the display shape, such as area E, have a transmittance that is the same as the background transmittance when the background electrode is turned on, or several orders of magnitude higher, preferably 01.
If the cell spacing and the helical pitch of the liquid crystal are set so that the transmittance is reduced by ~5%, the colorless state will always be maintained.

In the embodiment of the invention shown in FIGS. 3 and 4,
The relationship between the 0N10FF of switches 9, 10, and 11 and the display is shown in Table 1 below.

EXAMPLE A dust-host type liquid crystal display device of the present invention can be made according to the following recipe.

(1) Silane cassilling agent R KBM-403J 1% isonorobyl alcohol solution (Shin-Etsu Silicon (&) JM) was applied to the electrode substrate patterned in a predetermined shape at 3000 rpm for 10 seconds, and then heated at 130°C for 1 hour.
Heat for 5rnin.

(2) IQ see polyimide at 3000 rpm
After spin coating, heat at 300'C for 30 min.

(3) After removing the film formed by the process outside the effective display area and the polyimide formed in step (2) by resist printing and etching, the resist is peeled off.

(4) Heat at 300℃ for 30 minutes.

(5) 7# Tresist FPPR-soo (Fuji Pharmaceutical)
was applied by spin coating at 2000 rpm for 10 seconds.

(6) After preheating at 80° C. for 10 min, a prescribed photomask is closely attached and ultraviolet rays are irradiated.

(7) Wash with water after developing with a special developer.

(8) Heat at 80°C for 15 minutes.

(9) After applying a vertical alignment agent (rFs-116J, a fluorine-based silane agent manufactured by Daikin Industries, Ltd.) using a spinner, preheating is performed at 1.00° C. for 10 minutes.

(10 Peel off the photoresist.

0◇Heat at 200°C for 30 min.

Rub in the direction of an angle of 45 to the substrate.

(13) After printing and assembling an empty cell with a sealant, inject liquid crystal with the following composition and sealing the injection port.

Liquid crystal ZL, l-2011 (dichroic dye liquid crystal manufactured by Merck & Co., Ltd.) 98wt% C'M-20 (manufactured by Chisso Corporation) 2wt% or more A cell prepared by the method was heated by applying a voltage of about 8°C. Driven.

When the voltage is OFF, the area that has been subjected to the direct alignment process loses its color and the other areas tend to turn blue, but when the background electrode is
N. When the display electrode is turned off, the blue color is clearly displayed on the display area. At this time, the vertical alignment region and the background region had almost the same transmittance, and therefore could not be distinguished. If a difference occurs due to variations in cell spacing, it can be adjusted by adjusting the voltage of the background electrode.

Next, when the background electrode was turned on and the display electrode was turned on, the entire surface became discolored.

Normally, a voltage is applied to the background electrode and the display electrode, and when information is displayed, only the display part is turned off. This creates an apparent positive display, allowing the viewer to see a clear display from a colorless state. I could see it.

According to the present invention, the following effects can be obtained.

(1) Since Np liquid crystal is used, compared to Nn liquid crystal,
A wide variety of dyes with good characteristics can be selected, and display with good contrast can be achieved.

(2) Since the wiring lines are vertically oriented and cannot be seen, the wiring can be made thicker than in the past, and voltage drops, disconnections, and short circuits can be prevented.

(3) Since there is no need to form electrodes in the hollow/main turn, restrictions on routing and display shape are reduced.

(4) Since the vertical alignment area is not the entire surface but a relatively small area, the coloring of the vertical alignment area due to variations in cell spacing is not noticeable, and the transmittance can be almost equal to the background by adjusting the voltage. Configurable.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional liquid crystal display device, and FIG. 2 is a plan view showing an example of a pattern of a segment substrate of a conventional liquid crystal display device. 3 and 4 are a cross-sectional view of a liquid crystal display device according to the present invention and a segment substrate. This is an example of a turn. DESCRIPTION OF SYMBOLS 1... Upper board (segment board), 2... Lower board (common board), 3... Common electrode, 4... Background electrode, 5... Display 'ε pole (segment electrode), 6 ...Liquid crystal, 7...Dichroic dye, 8...Interval part, 9,10
．． 11... Switch, 12... Power supply, A, B, C, D, E, F... Area. 8 CBCA

Claims (1)

[Claims] In an electro-optical device, a layer containing a mixture of a dichroic dye, a nematic liquid crystal having positive galvanic anisotropy, and an optically active substance is arranged in a gap formed by a pair of substrates having electrodes. , electrodes are provided over substantially the entire surface of the display section, except for the electrode-free contours that form the display pattern, and electrodes are provided on substantially the entire surface of the display section, and the electrode-free portions of the display section, the segment' electrodes, or the common'N, have the best display shape. 1. An electro-optical device characterized in that a region between a portion not involved in the process and a substrate facing the same is vertically aligned, and other regions are horizontally aligned.