JPH05289081A - Orientation restoring method for ferroelectric liquid crystal element - Google Patents

Abstract

PURPOSE:To improve the yield of manufacture by executing an orientation restoration by applying an electric field and shearing by an orienting device or a manual work to a liquid crystal element in which an orientation disorder is generated in a mounting stage. CONSTITUTION:A liquid crystal element formed by inserting and holding a ferroelectric liquid crystal material between two pieces of flexible data electrode substrate 11 and flexible common electrode substrate 21 is subjected to orientation processing, and thereafter, at least cut, and after this cutting, a liquid crystal element part in which an orientation disorder is generated is selected and taken out. Subsequently, the orientation restoration is executed by applying simultaneously an electric field and shearing to the taken-out liquid crystal element part again by using an orienting device and a roll orienting device or the orientation restoration is executed by a manual work by applying a voltage from a power source unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferroelectric liquid crystal element alignment restoration method used for alignment restoration of a ferroelectric liquid crystal element used in a liquid crystal display device such as an electronic device.

[0002]

2. Description of the Related Art Conventionally, a substrate having a liquid crystal material with electrodes, particularly,
As a method for orienting a liquid crystal element sandwiched between flexible substrates, there is a method for orienting a liquid crystal material disclosed in JP-A-3-5727. In this orientation method, the liquid crystal element is sandwiched between two plastic plates for sandwiching the liquid crystal element, and the front and back are alternately closely adhered to each other by a pair of two roller parts, and shearing force is applied by bending deformation. .. In this case, the voltage is applied from the power supply voltage through an electric wire sandwiching the liquid crystal material of the liquid crystal element and connected to the electrodes of the respective electrode-attached substrates.

Furthermore, in the "method and apparatus for aligning a liquid crystal optical element" disclosed in JP-A-3-163525, a power source is connected in advance to two conductive rolls made of a conductive material and a voltage is applied. Is being applied. Then, the electrodes facing each other of the liquid crystal element sandwiching the liquid crystal material are exposed, and the electrodes are closely adhered to the surface of the roller alternately on the front and back sides to simultaneously apply the electric field and the shearing.

[0004]

However, Japanese Patent Application Laid-Open Nos. 3-5727 and 3-16 shown in this prior art example.
In the alignment method of No. 3525, the liquid crystal element subjected to the alignment treatment is
The device was cut for mounting the device, and the alignment disorder generated after the cutting was not repaired, and the liquid crystal element in which the alignment disorder was generated was not used. Therefore, there is room for improvement from the viewpoint of improving the manufacturing yield.

The present invention has been made in view of the above problem transition, and the alignment can be repaired again by applying an electric field and shear to the liquid crystal element in which the alignment is disturbed at the mounting stage by the aligning device or manually. It is an object of the present invention to provide a method for repairing alignment of a ferroelectric liquid crystal device, which improves the manufacturing yield.

[0006]

In order to achieve the above object, a method for repairing alignment of a ferroelectric liquid crystal device according to the present invention is a liquid crystal device in which a ferroelectric liquid crystal material is sandwiched between two flexible substrates with electrodes. After the alignment treatment, at least cutting is performed, and the liquid crystal element portion in which the alignment disorder occurs after this cutting is selected and taken out, and the electric field and shear are again applied to the taken out liquid crystal element portion to perform the alignment restoration, which is necessary. Depending on the condition, the common electrode and the segment electrode of the liquid crystal element in which the alignment disorder is generated are electrically connected to restore the alignment by applying an electric field and shear, and when the common electrode and the segment electrode are electrically connected. , A silver paste, a conductive tape, a conductive sheet, an aluminum foil, a copper foil, or a combination thereof is connected to the common electrode and the segment electrode, and they are arranged by applying an electric field and shearing. Repair and performs.

Here, the liquid crystal element will be described. The liquid crystal element is formed by sandwiching a ferroelectric liquid crystal material between two flexible substrates with electrodes. In this case, the ferroelectric liquid crystal material is preferably one having a chiral smectic C phase exhibiting a ferroelectric phase such as a low molecular weight compound, a polymer, or a mixture. Examples of liquid crystals having a ferroelectric liquid crystal state include ferroelectric low molecular liquid crystals, ferroelectric polymer liquid crystals, and mixtures thereof. Here, the ferroelectric low-molecular liquid crystal includes, for example, one or more kinds of ferroelectric low-molecular liquid crystals, and a mixture of one or more kinds of ferroelectric low-molecular liquid crystals and other low-molecular liquid crystals. Ferroelectric low-molecular liquid crystals and the like can be mentioned. Examples of the ferroelectric polymer liquid crystal include, for example, one or more kinds of ferroelectric polymer liquid crystals, one or more kinds of ferroelectric low-molecular liquid crystals, and one or more kinds of ferroelectric polymers. Examples thereof include a ferroelectric polymer liquid crystal composed of liquid crystal, a ferroelectric polymer liquid crystal composed of one or more kinds of ferroelectric low molecular liquid crystal, and one or more kinds of other polymer liquid crystal. That is, as the ferroelectric polymer liquid crystal, ferroelectric polymer liquid crystal (homopolymer or copolymer or mixture thereof) in which polymer molecules themselves exhibit ferroelectric liquid crystal characteristics, ferroelectric polymer liquid crystal and other Mixture of high molecular liquid crystal and / or ordinary polymer, mixture of ferroelectric high molecular liquid crystal and ferroelectric low molecular liquid crystal, ferroelectric high molecular liquid crystal, ferroelectric low molecular liquid crystal and high molecular liquid crystal, and / or Polymeric liquid crystals exhibiting all ferroelectric properties can be used, such as mixtures with common polymers or mixtures of these with normal low-molecular liquid crystals. Among the ferroelectric polymer liquid crystals, for example, a side chain type ferroelectric polymer liquid crystal having a chiral smectic C phase is preferably used.

Examples of the ferroelectric liquid crystal compound include desiloxybenzylidene-P'-amino-2-methylbutylcinnamate (DOBAMBC), hexyloxybenzylidene-P'-amino-2-chloropropylcinnamate (HOBACPC). And 4-o- (2-methyl)-
Butyl resorcylidene-4'-octylaniline (MB
RA8) and the like. When a device is formed using these materials, the liquid crystal compound is SmC * phase or SmH
* If necessary, the element can be supported by a copper block or the like in which a heater is embedded, which is maintained in a temperature state in which the phases are established. Further, the ferroelectric liquid crystal composition may contain an adhesive, a viscosity reducing agent, a non-liquid crystal chiral compound, a dye, etc., if necessary. Further, in the present invention, the aforementioned SmC *, S
In addition to mH *, chiral smectic F phase, I phase, J phase,
It is also possible to use a ferroelectric liquid crystal that appears in the G phase or the K phase.

Examples of flexible substrates with electrodes include crystalline polymers such as uniaxially or biaxially oriented polyethylene terephthalate, amorphous polymers such as polysulfone and polyethersulfone, polyolefins such as polyethylene and polypropylene, polycarbonates and nylon. And the like. Among these,
Particularly, uniaxially or biaxially stretched polyethylene terephthalate, polyether sulfone and the like are preferable. In the present invention,
The two flexible substrates may be made of the same material as each other, or may be made of different materials,
Usually, at least one of the above two substrates is made optically transparent, and a transparent electrode is provided for use.

The material for forming the liquid crystal driving electrode group formed on the flexible substrate is not particularly limited as long as it is a material having conductivity, but at least one of the electrodes has both conductivity and transparency. It is preferable to use a material having properties. Specifically, for example, ITO (IndiumTin) made of indium oxide or a mixture of indium oxide and tin oxide is used.
A transparent electrode such as an Oxide) film is preferably used. The method for forming the liquid crystal driving electrode on the flexible substrate is not particularly limited, and it is formed by a conventionally known method such as vapor deposition or sputtering. An alignment control film is not required on the electrodes, and an insulating film and a color filter for preventing conduction may be provided if necessary.

The method for sandwiching the ferroelectric liquid crystal material is not particularly limited, and the ferroelectric liquid crystal material may not be oriented depending on the sandwiching method. However, in consideration of productivity in high-speed manufacturing, the liquid crystal material is formed into a film. And laminate the substrate. In this case, a conventional film forming method, a coating method, or the like is used.

Next, the method for repairing the alignment of the ferroelectric liquid crystal element will be described. As an orientation method, an electric field and shearing are simultaneously applied at a temperature at which the liquid crystal material sandwiched between the substrates exhibits some liquid crystal phase other than the isotropic phase to perform uniaxial horizontal orientation. The temperature at this time is lower than the temperature at which the liquid crystal material exhibits an isotropic phase or a mixed phase of an isotropic phase and a liquid crystal phase. Specifically, a nematic phase (N phase), a cholesteric phase (Ch phase),
The temperature is set to indicate various smectic phases (Sm phases) or mixed phases thereof. When the temperature is high and in the isotropic phase (Iso phase), the liquidity of the liquid crystal material is too large to be aligned, and when the temperature is low and the glass phase or the crystalline phase is not sufficiently sheared, the liquid crystal material is not aligned. .. Preferably, the alignment treatment is performed at a temperature at which various smectic phases are exhibited.

Next, in the alignment treatment by the electric field and the shearing, the positive voltage and the negative voltage to be applied may be alternating current or direct current, and are applied continuously or intermittently. The preferred electric field is 0.1 to 150 MV / m, particularly preferably 5 to 150 M.
V / m. In this case, if the voltage is too low, the orientation becomes insufficient, and if the voltage is too high, dielectric breakdown of the liquid crystal element may occur. To apply an electric field and shear, use a roll for applying an electric field or a roll with a belt with an electrode together, or directly connect a power source to the common electrode and segment electrodes of the liquid crystal element and apply shear manually. Do it.

FIG. 1 shows the structure of a sheet-like liquid crystal element when this alignment restoration is performed. In FIG. 1, this liquid crystal element is electrically connected to a silver paste portion 13 electrically connected to a segment electrode group 12 of a flexible data electrode substrate 11 and a common electrode group 22 of a flexible common electrode substrate 21. The silver paste portions 23a and 23b are provided.
After the silver paste portions 13 and 23 are applied, they are dried to perform orientation restoration described below. After this orientation restoration, the silver paste portions 13, 23a, 23b are removed with a solvent or the like.
In addition to the silver paste material, the same action and effect can be obtained by using any one of conductive tapes, conductive sheets, and other conductors such as aluminum foil and copper foil, or a combination thereof.

Next, the alignment restoration in the liquid crystal element will be described. FIG. 2 is a schematic configuration diagram of an alignment device including a conductive roll for performing alignment restoration of the liquid crystal element shown in FIG. In FIG. 2, this example shows a sheet-like liquid crystal element 2.
Is attached to the biaxially stretched PET lumirror 4 and has a feeding device 6 for feeding the same, a winding device 8 for winding, and a roll electric field applying section 10. In this aligning device, the liquid crystal element 2 to be repaired is mounted on the biaxially stretched PET mirror 4
It is pasted on, and is fed by the feeding device 6 and wound by the winding device 8. At this time, the roll electric field application unit 10 applies a positive voltage and a negative voltage, respectively. This application brings the outer circumference of the roll into contact with the extraction electrode of the liquid crystal element 2, and simultaneously applies an electric field and shearing to restore the alignment. In addition,
In this alignment apparatus, alignment restoration for a roll-shaped (long) liquid crystal element can be similarly performed.

FIG. 3 is a schematic diagram of a roll orientation device provided with a belt with electrodes for performing orientation restoration. FIG. 3A shows a side structure, and FIG. 3B shows a front structure. 3A and 3B, in this example, a positive electric field applying section 2, a negative electric field applying section 4, an alignment roller section 6,
The voltage source E is roughly configured. The positive electric field applying unit 2 has an endless positive belt for applying a positive voltage 2a with electrodes, guide rollers 2b and 2c, and a positive voltage applying roller 2d. The negative electric field applying section 4 includes a lower belt 4a for applying a negative voltage with electrodes, guide rollers 4b and 4c, and a negative voltage applying roller 4
have d. The orientation roller unit 6 includes an upper belt 2a for applying a positive voltage with an electrode and a lower belt 4 for applying a negative voltage with an electrode.
a is composed of eight rollers that are joined and rotate. The upper belt 2a for applying positive voltage with electrode is provided with an electrode 2e for applying voltage, and the lower belt 4a for applying negative voltage with electrode is provided with an electrode 4e for applying voltage. In the alignment restoration using this roll alignment device, the liquid crystal element 10 to be restored is inserted and sandwiched between a pair of upper and lower positive belts for applying positive voltage 2a and lower belt 4a for applying negative voltage with electrodes.
A voltage is applied to apply an electric field through the applied silver paste portions 13, 23a and 23b. At the same time, the orientation roller unit 6 applies shearing to restore the orientation.

Furthermore, a method of connecting a power source directly to the liquid crystal element and applying shearing by hand will be described. FIG. 4 shows a configuration in which a power source is directly connected to the liquid crystal element to be repaired.
In FIG. 4, lead wires are connected to the positive (+) output terminal and the negative (-) output terminal of the power supply device 30 that outputs alternating current or direct current, and the tip of the paper clip 32,
34 is connected. Konomi-mushi Clip 32,3
4 between the flexible data electrode substrate 11 and the flexible common electrode substrate 21 of the liquid crystal element to be repaired shown in FIG.
An AC voltage or a DC voltage is applied to the liquid crystal element to be repaired from 0. Next, as shown in FIG. 5, after applying an AC voltage or a DC voltage from the power supply device 30, the human hands Ma, Mb
While manually bending the entire surface of the flexible common electrode substrate 21 in the longitudinal direction, that is, the extending direction of the common electrode group 22 of the flexible common electrode substrate 21 (in the arrow direction), shearing is manually applied to restore the orientation.

[0018]

EXAMPLES Examples of the method for repairing the alignment of the ferroelectric liquid crystal element of the present invention will be described in more detail below, but the present invention is not limited thereto. Example 1

[0019]

[Chemical 1]

A 28 wt% solution was prepared by dissolving a mixture of the above liquid crystal composition and PMMA (polymethylmethacrylate: Tg = 60 ° C.) in a weight ratio of 95: 5 in toluene. This solution was applied on a 100 μm thick, 150 mm wide, 20 m long electrode surface of a PES (polyethersulfone) substrate with ITO electrodes using a microgravure coater. Immediately after the evaporation of the solvent, a PES substrate with ITO electrodes was laminated on the opposite substrate to prepare a long liquid crystal element. Next, this long liquid crystal element is attached to FIG.
Alignment treatment was carried out at room temperature at a DC voltage of 50 V with the aligning device according to (a) and (b), and thereafter, a width of 15 cm and a length of 36 cm were cut. A liquid crystal element in which alignment disorder occurred due to the conduction of the substrate, handling, etc. was selected from among the prepared many liquid crystal elements. As shown in FIG. 1, the segment electrode group 12 of the flexible data electrode substrate 11 is applied to the selected liquid crystal element with disordered orientation.
A silver paste portion 13 which is applied to and electrically connected to, and silver paste portions 23a and 23b which are applied to the common electrode group 22 of the flexible common electrode substrate 21 and electrically connected,
Again, it was oriented by the roll orientation device shown in FIGS. As a result, uniform orientation was obtained on the entire surface. The alignment conditions in this case are as shown in Table 1 below. In addition, the contrast ratio before and after the alignment restoration is
It is as shown in Table 2 below. Even if the coating surface of the silver paste as described above had some irregularities, the electric field was sufficiently applied, and conduction could be reliably reduced.

Example 2 Liquid crystal A and liquid crystal B having the following structures were mixed in the following proportions to obtain a liquid crystal material having the following characteristics.

[0022]

[Chemical 2]

This liquid crystal material and polyisobutyl methacrylate manufactured by Mitsubishi Rayon Co., Ltd. (trade name: Dianal B)
A mixture of R-105) in a weight ratio of 6: 1 was used as a 10 wt% methylene chloride solution, and an ITO-attached polyethersulfone (PES) substrate (Sumitomo Bakelite Co., Ltd., FST-
1351, width 300 mm, thickness 100 μm, length 50
m) was used to form a film using a microgravure coater.
The film thickness after evaporation of the solvent was 1.8 μm. Then, it was laminated on a similar substrate on which nothing was applied, and an alignment treatment was carried out using the alignment apparatus shown in FIG. The alignment conditions were such that the alignment roll temperature was 50 ° C., DC -50 V was applied, and the transport speed was 2.0 m / min. As a result, 80% of all liquid crystal elements could be subjected to the alignment treatment, but the remaining 20% (10 liquid crystal elements) had many conductive portions and the alignment treatment was insufficient. Then, these are cut out into a width of 30 cm and a length of 90 cm, and the electrodes are provided with silver paste portions 13, 23a, and 23b in which a silver paste is applied with a width of 1 mm as shown in FIG. Orientation was performed. The applied voltage was DC-70V. At this time, in order to prevent the polarization of the liquid crystal element from being biased, polarity inversion and voltage application are applied to the plus (+) output terminal and the minus (-) output terminal from the power supply device 30 in FIG. 4 in the middle of the lead wire. A stop switch was provided to switch polarity inversion and voltage application stop arbitrarily. The results are shown in Table 3 below. [Table 3] ───────────────────────────────── Contrast ratio Continuity [mA] ──────── ────────────────────────── Before alignment repair After alignment repair Before alignment repair After alignment repair ──────────── ───────────────────── Liquid crystal element No. 1 2.0 60 20 200 ─────────────────── ─────────────── Liquid crystal element No. 2 1.0 59 35 0 ───────────────────────── ───────── Liquid crystal element No. 3 1.0 63 263 0 ─────────────────────────────── ─── Liquid crystal element No. 4 1.5 58 23 0 ──────────────────────────────── ─ Liquid crystal element No. 5 1.8 58 30 0 ────────────────────────────────── Liquid crystal element No. 6 1.0 57 50 0 ───────────────────────────────── Liquid crystal element No. 7 1.0 59 59 35 0 ───────────────────────────────── Liquid crystal element No. 8 1.5 65 30 300 ─────── ─────────────────────────── Liquid crystal element No. 9 2.0 63 153 ───────────── ───────────────────── Liquid crystal element No. 10 1.5 62 60 0 ─────────────────── ───────────────

[0024]

As described above, the ferroelectric liquid crystal element alignment repairing method of the present invention allows the liquid crystal element in which the alignment disorder occurs at the mounting stage to be subjected to the electric field and the shearing again by the aligning device or manually. In addition, the orientation can be repaired and the production yield can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a liquid crystal element when performing alignment restoration in a ferroelectric liquid crystal element alignment restoration method of the present invention.

FIG. 2 is a side view showing a schematic configuration of an alignment apparatus using a conductive roll for carrying out alignment repair in the ferroelectric liquid crystal device alignment repair method of the present invention.

FIG. 3 (a) is a side view showing a schematic configuration of a roll orientation device provided with a belt with electrodes for performing orientation restoration.
FIG. 3B is a front view showing a schematic configuration of a roll orientation device provided with a belt with electrodes for performing orientation restoration.

FIG. 4 is a perspective view showing a configuration in which a power source is directly connected to a liquid crystal element to be repaired in an example.

5 is a perspective view showing a working state in which a voltage is applied from the power supply device shown in FIG. 4 to perform orientation restoration.

[Explanation of symbols]

 11, 21 Flexible data electrode substrate 13, 23a, 23b Silver paste part 12 Segment electrode group 22 Common electrode group

Claims (3)

[Claims] 1. A liquid crystal device in which a ferroelectric liquid crystal material is sandwiched between two flexible substrates with electrodes is subjected to an alignment treatment, and then at least cut, and a liquid crystal device portion in which alignment disorder has occurred after this cutting is selected. A ferroelectric liquid crystal device alignment repair method, characterized in that an electric field and shear are applied again to the liquid crystal device portion thus taken out to repair the alignment. 2. The method for repairing the alignment of a ferroelectric liquid crystal device according to claim 1, wherein the common electrode and the segment electrode of the liquid crystal device in which the alignment disorder is generated are electrically connected and the alignment is repaired by applying an electric field and shear. 3. When electrically connecting a common electrode and a segment electrode, a silver paste, a conductive tape, a conductive sheet, an aluminum foil, a copper foil, or a combination thereof is connected to the common electrode and the segment electrode. Then, the alignment repair method according to claim 2, wherein the alignment repair is performed by applying an electric field and shearing.