JPS6381326A - Liquid crystal element - Google Patents

Abstract

PURPOSE:To prevent the generation of orientation disorder due to impulsions of impact and pressure by controlling particle number scattered between substrates to >=50-<=2,000 numbers per 1mm<2>. CONSTITUTION:The titled element is interposed a ferroelectric liquid crystal 10 between a pair of substrates 1 and 2 in which at least one of the substrates is transparent. In said element, the number of the particles 9 scattered between the substrates 1 and 2 are controlled to >=50-<=2,000 number per 1mm<2> and the diameter of the particle 9 is a range of 1-4mum. Thus, the impact resistance and the proof resistance strength with respect to the ferroelectric liquid crystal 10 are improved, and a phenomenon of the orientation disorder due to an external cause does not appear within a practical use.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a liquid crystal element using ferroelectric liquid crystal.

(Prior Art) Generally, liquid crystal elements are used in a wide range of electro-optical devices such as wristwatches, calculators, personal computer displays, and pocket color televisions.

However, the currently used nematic liquid crystal has a slow electro-optic response time of about 50 msec, which limits its use in fields where high-speed response is required.

Furthermore, the display capacity of the current TN (twisted nematic) system is reaching its limit, and new systems that exceed the TN system are being actively sought.

Among these, ferroelectric liquid crystals are expected to be put to practical use because they exhibit high-speed response on the microsecond scale and have memory properties, so there is no limit to display capacity.

(Problems to be Solved by the Invention) Liquid crystal elements using ferroelectric liquid crystals as described above have a drawback that alignment is disturbed by application of impact or pressure. Even in liquid crystal elements using nematic liquid crystals, alignment disturbances occur due to impact or pressure. However, since nematic liquid crystals have properties similar to liquids, even if the -direct alignment is disturbed, recovery to the initial alignment is easy.

On the other hand, ferroelectric liquid crystals have properties close to solids, so -
Spontaneous recovery of perturbed orientation is difficult.

This misaligned portion no longer exhibits the desired optical response upon application of an electric field, significantly deteriorating its performance as a liquid crystal element. In other words, in a liquid crystal element using ferroelectric liquid crystal, the phenomenon of alignment layer deviation is a fatal problem.

Conventionally, in liquid crystal elements using nematic liquid crystal, as shown in Japanese Patent Publication No. 58-56850, for example,
0.7 to 9 spacers per 1 mm are used between the substrates of a liquid crystal element.

However, when a ferroelectric liquid crystal element is manufactured using spacers having the above distribution density, the impact resistance and pressure resistance strength are insufficient, and the above-mentioned alignment layer deterioration easily appears.

Also, if the number of spacers exceeds 2000 per 1m,
Defect lines begin to appear during liquid crystal alignment, and a phenomenon similar to alignment layer deformation caused by impact or pressure application is observed.

On the other hand, the diameter of the particles to be dispersed is preferably in the range of 1 to 4 μm. If the diameter of the particles is 1 μm or less, it is difficult to control the gaps between the substrates to have a uniform thickness when the substrate area is increased. If the diameter of the particles is 4 μm or more, no memory effect will be observed in the liquid crystal device, and the device will no longer function as a device.

An object of the present invention is to provide a liquid crystal element that prevents the occurrence of alignment layer deterioration due to the application of impact or pressure by increasing the strength of ferroelectric liquid crystal against impact or pressure.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a liquid crystal element in which a ferroelectric liquid crystal is sandwiched between a pair of substrates, at least one of which is transparent, in which the number of particles scattered between the substrates is reduced. is set to 50 or more and 2000 or less per 1 mm, and the particle diameter is in the range of 1 to 4 μm.

(Function) According to the present invention, since the above-mentioned measures are taken, the impact resistance and pressure resistance of the ferroelectric liquid crystal are increased,
Within a practical range, the phenomenon of alignment layering due to external factors is no longer observed.

(Embodiments) Hereinafter, some embodiments of the present invention will be described with reference to the drawings.

[Example 1] Fig. 1 shows a liquid crystal element according to an example of the present invention, in which a pair of substrates 1.2 made of transparent glass and having an area of 90x90I1m and a thickness of 1M1 are arranged facing each other. It is set up. Then, electrodes 3 are provided on the opposing surfaces of each substrate 1.2.
．． 4 is formed, and on this electrode 3.4 a horizontal alignment layer 5.4 is formed.
6 are respectively deposited. Further, between each of these substrates 1.2, microparticles 9 and ferroelectric liquid crystal 10 are formed in a horizontal alignment layer 5.2.
The liquid crystal element 11 is sandwiched in contact with the liquid crystal element 6.

In use, polarizing plates 12 and 13 are provided on both sides of the liquid crystal element 1, as shown in FIG.

Next, a method for manufacturing this liquid crystal element 11 will be explained.

First, transparent electrodes 3.4 of a predetermined shape made of Nesa film are formed on one side of each substrate 1.2. Next, electrode 3.4
Polyimide resin (Lx140
0: manufactured by Hitachi Chemical Co., Ltd.) was applied to a thickness of 500 mm using a spinner, and rubbed in a uniaxial direction of 7.8 mm using a rubbing machine to form a horizontal alignment layer of 5.6 mm.

The invasion occurs between the substrates 1.2 as microparticles 9 with a diameter of 2 μm.
1 m of alumina crystal (Alfit: manufactured by Showa Denko)
The substrates 1.2 are bonded together by scattering so that the number of distributions per unit area is approximately 100. In addition, the distribution number of alfits varies depending on the location, and is actually 80 to 15.
There were 0 pieces.

Next, a liquid crystal (CS-1001: manufactured by Chisso Corporation) exhibiting dielectric properties at room temperature is sealed between these substrates 1.2 to form a liquid crystal element 11.

Next, as shown in FIG. 2, a polarizing plate 13 with a polarizing axis 13a shifted by 22 degrees from the rubbing direction 7 of the horizontal alignment layer 5 is installed on the substrate 1, and the polarizing axis 13a of the polarizing plate 13 and the polarizing axis Another polarizing plate 12 with orthogonal polarizing plates 12a is installed on the substrate 2.

Now, using the above liquid crystal element manufacturing method 1,
Although the drop test from 0α was repeated 10 times, it was confirmed by observation using a polarizing microscope that there was no disturbance in the orientation at all.

Further, when a drop test was conducted from 80 cm on an oak wooden board, the glass substrate of the liquid crystal element was damaged.

Furthermore, an impact resistance test was conducted using an impact tester, and an impact of 30'G x 11 ms was applied to the liquid crystal element, but no disturbance in alignment occurred.

[Example 2] In this Example 2, the number of Alfit distributions used in the above Example 1 is set to approximately 200 per 1 TrL-unit area. Incidentally, the actual number of distributed Alfits was 180 to 240. In this case as well, both the drop test and impact resistance test of the liquid crystal element showed exactly the same results as in Example 1 above.

[Example 3] In this Example 3, Alfit used in Example 1 above was replaced with microbars (manufactured by Sekisui Fine Chemical Co., Ltd.) having a diameter of 3 μm, and the particles were dispersed at a distribution rate of 100 per unit area of 1 mff. . The actual distribution number of microbars was 80 to 160. In this case as well, both the drop test and impact resistance test of the liquid crystal element showed exactly the same results as in Example 1 above.

[Comparative Example 1] In Comparative Example 1, a liquid crystal element was manufactured so that the number of alphanumeric distributions in Example 1 was 3 per 1 TrLTft unit area. The actual distribution number of alfits was 0.7 to 9 per unit area of TrLTd.

Using this liquid crystal element, a drop test from 30CW1 on an oak wooden board was conducted in the same manner as in the above example.
Disturbance of orientation occurred in the area of . This disorder of orientation is 1
Even after leaving it for a day, it did not recover, ±10.

It was confirmed that the device showed no optical response even to the application of a direct current electric field (2), and that its performance as a liquid crystal element was lost.

Furthermore, when the same impact test as in Example 1 was conducted,
Disturbance of orientation occurred in an area of 20 m. This portion of disordered orientation did not recover even after being left for one day, and no electro-optical response was exhibited at all even when a DC electric field of ±10 V was applied.

[Comparative Example 2] In Comparative Example 2, a liquid crystal element was manufactured by changing the distribution number of Alfit used in Example 1 to 30 per 1 mTd unit area. The actual distribution number of Alfits was 20-40.

Using this liquid crystal element, a drop test from 30 cIl on an oak wooden board was conducted in the same manner as in the above example.
Disturbance of orientation occurred in the area of . This disorder of orientation is 1
It did not recover even after being left in the sun, and showed no optical response to the application of a DC electric field of ±10 V, confirming that its performance as a liquid crystal element had been lost.

Furthermore, when the same impact test as in Example 1 was conducted,
Disturbance of orientation occurred in an area of 5d. This portion of disordered orientation did not recover even after being left for one day, and no electro-optical response was exhibited at all even when a DC electric field of ±10 μm was applied.

[Example 4] In this Example 4, a liquid crystal element was manufactured in such a manner that the distribution number of Alfit used in Example 1 was 1500 per 1 mm unit area. The actual distribution number of Alfits was 1,400 to 2,000.

In this case as well, both the drop test and impact resistance test of the liquid crystal element showed exactly the same results as in Example 1 above.

[Example 5] In this example 5, the thickness of the substrate 1.2 used in the above example 1 was changed to 2M, and the number of alpha distributions was changed to 1TrL.
It is set to be 70 pieces per unit area of Td. The actual distribution number of Alfits was 50-80. In this case as well, both the drop test and impact resistance test of the liquid crystal element showed exactly the same results as in Example 1 above.

[Embodiment 6] In this Embodiment 6, the distribution number of alfits in the above Embodiment 5 is set to 1500 per unit area of 1771 m. The actual distribution number of Alfit is 14
The number was 00 to 2000. In this case as well, both the drop test and impact resistance test of the liquid crystal element showed exactly the same results as in Example 1 above.

[Comparative Example 3] In Comparative Example 3, a liquid crystal element was manufactured by changing the distribution number of Alfit used in Example 5 to approximately 3 per unit area of 1 TrL. The actual distribution number of Alfit is 0
．． There were 7 to 9 pieces.

When this liquid crystal element was subjected to a drop test from an oak wooden board 301 in the same manner as in the above example, alignment disturbance occurred in an area of 22 ci. This disordered orientation did not recover even after being left for one day, and no optical response was shown even when a DC electric field of ±10 V was applied, confirming that the performance as a liquid crystal element was lost.

Furthermore, when the same impact test as in Example 1 was conducted,
Disturbance of orientation occurred in the area of 12i. This portion of disordered orientation did not recover even after being left for one day, and no electro-optical response was exhibited at all even when a DC electric field of ±1"0" was applied.

[Comparative Example 4] In Comparative Example 4, a liquid crystal element was manufactured using the Alfit distribution number used in Example 5 above as 30 rfA per 1 TrL 11 L unit area. The actual distribution number of Alfits was 20-40.

Using this liquid crystal element, a drop test from 30cIR on an oak wooden board was conducted in the same manner as in the above example, and the result was 8cI.
Disturbance of orientation occurred in the area of i. This disordered orientation is
It did not recover even after being left for one day, and showed no optical response to the application of a DC electric field of ±10 V, confirming that its performance as a liquid crystal element had been lost.

Furthermore, when the same impact test as in Example 1 was conducted,
Disturbance of orientation occurred in an area of 3cIi. This portion of disordered orientation did not recover even after being left for one day, and no electro-optical response was exhibited at all even when a DC electric field of ±10 V was applied.

[Comparative Example 5] In Comparative Example 5, a liquid crystal element was manufactured using the Alfit distribution number used in Example 1 as approximately 2500 per 1 m area. The actual distribution number of Alfit is
The number was 2,300 to 3,000.

In this case, defect lines were generated over almost the entire area of the liquid crystal alignment, and the alignment was disordered.

[Comparative Example 6] In Comparative Example 6, a liquid crystal element was manufactured using the Alfit distribution number used in Example 5 as approximately 2,500 per unit area of 1,771 m. The actual distribution number of Alfits was 2,300 to 3,000.

In this case, defect lines were generated over almost the entire area of the liquid crystal alignment, and the alignment was disordered.

[Effects of the Invention] As described above, according to the present invention, two substrates 1.
The number of microparticles 9 scattered between 2 and 2 is set to 50 per 1TrLTd.
By increasing the number of layers, it is possible to enhance the impact resistance and pressure resistance of the liquid crystal element, and to prevent the occurrence of alignment layer deterioration.

Therefore, by using the liquid crystal element of the present invention, it is possible to realize a large-capacity liquid crystal element of an X-Y simple matrix type that does not use active elements.

It goes without saying that at least one of the substrates 1.2 should be transparent for visual recognition, and that the ferroelectric liquid crystal 10 can be selected from a wide variety of materials such as phenylpyrimidine.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a liquid crystal element according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the same. 1.2... Substrate 3.4... Electrode 5.6... Horizontal alignment layer 7.8... Rubbing direction 9... Microparticles 10... Ferroelectric liquid crystal 11-... Liquid crystal Element 12
．． 13...Polarizing plate.

Claims (2)

[Claims] (1) A liquid crystal element in which a ferroelectric liquid crystal is sandwiched between a pair of substrates, at least one of which is transparent, characterized in that the number of particles scattered between the substrates is 50 or more and 2000 or less per 1 mm^2. A liquid crystal element. (2) The liquid crystal element according to claim 1, wherein the diameter of the particles is in the range of 1 to 4 μm.