JP3244563B2 - Manufacturing method of nematic liquid crystal panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal panel.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal panel has a structure in which liquid crystal is held between upper and lower glass substrates having transparent electrodes. Therefore, for example, when the conductive foreign substance has a size equal to or larger than the cell thickness, a short circuit may occur between the upper and lower substrates.

If these conductive foreign substances are completely adhered between the upper and lower substrates, a short circuit can be easily inspected by applying an electric field in actual use. However, the electric field strength that causes dielectric breakdown (upper and lower shorts) differs depending on the conductivity of the foreign matter or the contact state between the upper and lower substrates. For this reason,
In the upper and lower short-circuit inspection, in order to make the above-mentioned potential upper and lower short-circuits more apparent, the inspection is performed with a higher electric field and lower frequency than the actually used driving waveform.

[0004]

However, when a high electric field and a low frequency are applied to the liquid crystal panel as described above, a problem arises in that deterioration of display quality such as rubbing scratches and pinholes is emphasized. Further, the ferroelectric liquid crystal has a problem that bistability is impaired and the memory becomes one-sided.

[0005]

In order to solve the above-mentioned problems, the present invention provides a method of manufacturing a liquid crystal panel in which a high electric field or a low frequency electric field is applied to a liquid crystal panel, and then temperature annealing is performed.

[0006]

The operation of the present invention will be described below with reference to the drawings. FIG. 1 shows a case where a high electric field or low frequency waveform is applied to a liquid crystal panel.

FIG. 1A shows a state before an electric field is applied to the liquid crystal panel 11. Ions 12 exist in the liquid crystal panel, and the alignment film 13 or the overcoat 14 serves as an insulating film.
Is provided. When a high electric field or a low-frequency electric field is applied, ions are localized in the direction of the electric field as shown in FIG. At this time, a higher voltage is applied to the liquid crystal layer 15 in the portion 16 having a different alignment film thickness (for example, a rubbing scratch or a pinhole in the alignment film 13) and in the portion having a small film thickness as compared with the thick portion. For this reason, the amount of the unevenly distributed ions is larger at a thinner film thickness.

That is, when actual driving is performed, the uneven distribution of these ions becomes a bias voltage, the difference in electro-optical characteristics becomes large, and display unevenness occurs. By annealing such a liquid crystal panel with temperature, FIG.
Ions unevenly distributed as in c) are diffused, and good display quality can be obtained. Also, ions can be diffused by a high-frequency electric field.

In a ferroelectric liquid crystal, as shown in FIG. 2, spontaneous polarization 24 of liquid crystal molecules becomes stable in the direction of an electric field 23 caused by ions 22 unevenly distributed on a substrate 21. As a result, the C director 25 is stabilized to one side, so that bistability cannot be obtained, resulting in a one-sided memory property.

[0010]

Embodiment 1 Hereinafter, Embodiment 1 will be described. As a configuration of a liquid crystal element actually used, a liquid crystal element in which a transparent conductive film (indium-tin oxide: ITO film) was formed on a glass substrate was used.

A polyimide SE4110 manufactured by Nissan Chemical Industries, Ltd. was applied on the ITO film by a printing method. Curing temperature 220
C. for 1 hour in a clean oven. Printing was performed so that the thickness of the polyimide film was about 1000 °.

The upper and lower substrates were subjected to a rubbing treatment so as to have a TN (twist 90 degrees counterclockwise). Micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.) (average particle diameter 6μ)
m) was evenly applied.

A seal was formed on the other substrate by screen printing an epoxy-based adhesive. Thereafter, the respective substrates were bonded together and heated and cured at 160 ° C. for 1 hour while being uniformly pressed at a pressure of about 1 kg / cm 2.

After curing, liquid crystal material ZL manufactured by Merck Ltd.
To I2293, a chiral agent S811 manufactured by Merck Ltd. was added so as to have a pitch of 100 μm, and mixed by heating. The above-mentioned liquid crystal material was injected by a normal vacuum injection method, and sealed with an epoxy adhesive. After sealing, annealing was performed at 120 ° C. for 12 hours in order to reduce the influence of uneven injection and the like.

The liquid crystal panel manufactured in this manner has a voltage of 50 V,
A voltage of 10 Hz was applied for 5 seconds. After that, when the electro-optical change is observed while gradually applying a voltage of 60 Hz close to the normal actual driving condition, rubbing scratches and alignment film unevenness that were not seen before the application of the low frequency high voltage are emphasized. Was observed.

When this panel was annealed again at 120 ° C. for 1 hour, the original uniform display was obtained. The annealing temperature is 100 ° C., 90 ° C., 80 ° C., 70 ° C., 60 ° C.
However, although the effect was obtained, there was a tendency that a longer annealing time was required as the temperature became lower.

Even when a high-frequency electric field of 60 V and 5 KHz was applied for 60 seconds to the panel to which the above-mentioned low-frequency high voltage was applied, a uniform display was similarly obtained. 50 for high frequency electric field
Similar results were obtained with V, 40 V, 30 V, and 20 V, but the printing time tended to be longer. (Embodiment 2) Hereinafter, Embodiment 2 of the present invention will be described.

A super twisted nematic liquid crystal cell (S
TN cell). The alignment film used was Nissan Chemical Co., Ltd.
SE4110 manufactured by KK was used. The curing temperature was 200 ° C. for 1 hour, and the film thickness was about 1000 °. As a liquid crystal material, ZLI2293 manufactured by Merck Ltd. was used. The cell thickness was set to about 6.3 μm by spraying a micropearl average particle diameter of 6 μm.

The added chiral agent is R8 manufactured by Merck Ltd.
11, the pitch was added so as to be 11 μm, and the rubbing configuration was clockwise. Inject liquid crystal,
After sealing, 120 to reduce the influence of uneven injection etc.
Annealing was performed at 12 ° C. for 12 hours.

The liquid crystal panel thus manufactured is supplied with 50 V,
A voltage of 10 Hz was applied for 5 seconds. After that, when the electro-optical change is observed while gradually applying a voltage of 60 Hz which is close to a normal actual driving condition, rubbing scratches and alignment film unevenness which were not observed before the application of the low frequency high voltage are emphasized. Was done.

When this panel was annealed again at 120 ° C. for 1 hour, the original uniform display was obtained. The annealing temperature is 100 ° C, 90 ° C, 80 ° C, 70 ° C, 60 ° C
However, although the effect was obtained, there was a tendency that a longer annealing time was required as the temperature became lower.

Even when a high-frequency electric field of 60 V and 5 KHz was applied for 60 seconds to the panel to which the above-mentioned low-frequency high voltage was applied, a uniform display was similarly obtained. Embodiment 3 Hereinafter, Embodiment 3 will be described.

A glass substrate with a transparent electrode is washed and dried with an alkaline detergent in a usual manner, and then an ether-based silane coupler X641-12 is formed on the substrate as an alignment film.
Using a 0.1 wt% ethanol solution of (Shin-Etsu Silicone Co., Ltd.), the solution was applied by a spinner method under conditions of 2000 rpm for 15 seconds, and dried at 150 ° C. for 1 hour.

Thereafter, two substrates were rubbed with a normal rotary rubbing device (Liquid Cell Rubbing Device manufactured by Iinuma Gauge Co., Ltd.) to give alignment ability. At this time, the substrates were rubbed so that the orientation was antiparallel between the two substrates.

Thereafter, a liquid crystal panel was manufactured by laminating the two substrates. At this time, a desired cell thickness was obtained by screen printing Structural Bond manufactured by Mitsui Toatsu Co., Ltd. as a sealing resin, and uniformly spraying Micro-Pearl manufactured by Sekisui Fine Chemical Co., Ltd. according to the cell as a cell gap adjusting material.

The cell thickness was 2 μm. The liquid crystal material was sealed by a vacuum injection method using a ferroelectric liquid crystal CS1013 manufactured by Chisso Corporation. After injecting and sealing the liquid crystal, annealing was performed at 100 ° C. for 8 hours to reduce the influence of uneven injection and the like.

The ferroelectric liquid crystal panel thus produced exhibited good alignment and good memory characteristics. A voltage of 40 V and 10 Hz was applied to the ferroelectric liquid crystal panel thus manufactured for short-circuit inspection for 5 seconds. After that, when the memory property was observed by a normal pulse electric field, the memory property was not expressed, and it was not bistable but one-sided.

When this panel was annealed at 100 ° C., the memory property was developed. Further, even when a high-frequency electric field of 30 V, 1 KHz, which is a high-frequency electric field, is applied to this half-stable panel, the memory property is developed.

[0029]

As is clear from the above description, the present invention applies a high electric field or a low frequency electric field to a liquid crystal panel for inspection of vertical short circuit or the like and then applies a temperature annealing or a high frequency electric field to apply a high electric field or a low electric field. This has the effect of making the display quality damaged by the frequency electric field uniform.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an operation in a step of a liquid crystal panel manufacturing method of the present invention.

FIG. 2 is a schematic view showing the operation of the ferroelectric liquid crystal of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Liquid crystal panel 12 Ion 13 Alignment film 14 Overcoat 15 Portion with different alignment film thickness

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-245125 (JP, A) JP-A-4-246623 (JP, A) JP-A-3-5719 (JP, A) JP-A-4-245 343323 (JP, A) JP-A-3-259215 (JP, A) JP-A-3-122617 (JP, A) JP-A-2-240634 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/13 101 G02F 1/1337-1/1337 530 G02F 1/1343

Claims (6)

(57) [Claims] 1. After applying a voltage having a lower frequency than a driving waveform in actual use to a nematic liquid crystal panel,
Preparation of warm annealing to Rene Matic crystal panel a nematic liquid crystal panel. 2. A method in which a voltage having a frequency lower than that of a driving waveform in actual use is applied to a nematic liquid crystal panel .
A method of manufacturing a nematic liquid crystal panel, wherein the nematic liquid crystal panel is heated and annealed after performing an upper and lower short-circuit inspection . 3. Driving of a nematic liquid crystal panel in actual use
After applying a voltage having a lower frequency than the waveform,
Higher than actual drive waveform for nematic liquid crystal panel
A voltage that has a frequency and is higher than the driving waveform in actual use
Method for producing a nematic liquid crystal panel. 4. Driving of a nematic liquid crystal panel in actual use
By applying a voltage having a lower frequency than the waveform
After performing an upper and lower short inspection, the nematic liquid crystal panel
Has a higher frequency than the actual driving waveform in the
A method for manufacturing a nematic liquid crystal panel that applies a voltage higher than the driving waveform at the time of actual use . 5. The annealing temperature of a nematic liquid crystal panel is
The temperature is higher than an actual use temperature.
3. The method for producing a nematic liquid crystal panel according to 2. 6. An annealing temperature for a nematic liquid crystal panel.
Is the temperature at which the nematic liquid crystal becomes an isotropic liquid.
The nematic according to claim 1, claim 2, or claim 5.
LCD panel manufacturing method.