JPS604858B2 - Nematic liquid crystal composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to novel nematic liquid crystal compositions.

More specifically, the present invention relates to a white and very stable nematic liquid crystal composition. In recent years, advances in electronics and other technologies have created a demand for inexpensive display materials that can be driven at low voltages.

Liquid crystals are currently seen as a promising display material that meets this demand, and liquid crystals are already being used in some displays. This promising liquid crystal is made of organic compounds,
While ordinary compounds change from solid to liquid to gas, liquid crystals do not directly change from solid to liquid, but have a state in which they have both the properties of solid and liquid.

A liquid crystal display is a display that applies this unique characteristic when in a trough state to a display.

The methods currently widely used include the light scattering method and the field effect method. The present invention was made regarding a liquid crystal composition used in a field effect display. Although liquid crystals are very promising as display materials, conventional liquid crystal materials still have the following drawbacks and points for improvement. 1 Conventional liquid crystals were mainly compounds with a Schiff base at the center of the molecule.

However, this liquid crystal was easily affected by moisture and was difficult to handle. 2. Azoxy compound-based liquid crystals are relatively stable liquid crystals.

However, since this liquid crystal absorbs light in the visible region, it has the disadvantage that it deteriorates even when exposed to visible light such as ultraviolet rays. In order to eliminate this drawback, the display part is protected with a colored filter, but with this method, the entire display part is colored in a specific color.
The disadvantage is that it becomes dark and the display ability deteriorates. 3 1 and 2 above
As a liquid crystal that does not have these drawbacks, there is a white and very stable liquid crystal made of an ester compound, but this conventional liquid crystal has a very limited temperature range and is subject to restrictions in terms of use.

For example, a liquid crystal composition comprising a liquid crystal represented by the general formula (R is a chain alkyl group) has been considered.

However, this liquid crystal composition had the disadvantage that the upper limit point at which it ceases to be a liquid crystal (clear point, hereinafter abbreviated as CP) was 5000 or less, which was too low.

A liquid crystal composition was also considered in which a liquid crystal represented by the general formula (R, R' means a straight mirror alkyl group) was mixed with the liquid crystal compound, but this liquid crystal composition also had a CP of 50.
℃ or less, which was not satisfactory.

In addition, ester liquid crystals have the disadvantage that they cannot maintain a supercooled state for a long time compared to other liquid crystals having a Schiff base at the center of the molecule or liquid crystals of azoxy compounds. For this reason, even if products were manufactured, it was difficult to use them in cold regions. By mixing the seven types of ester compounds shown in Table 1, the present invention solves not only the drawbacks mentioned in 1 and 2 above, but also the drawbacks mentioned in 3 above of conventional ester compounds. This is what I did.

Table 1 shows the properties of the liquid crystal compound used in the present invention. Table 1 In Table 1, the symbols C, N, and 1 represent a crystalline state, a nematic liquid crystal state, and an isomallic liquid state, respectively.

The same applies to the table below. Example 1 shows the components of the nematic liquid crystal composition of the present invention prepared using the compounds shown in Table 1, their proportions, and an example of their properties.

Example 1 As can be seen from Example 1, the mp of the liquid crystal composition of the present invention is several degrees lower than that of conventional liquid crystal compositions, and the CP is sufficiently maintained at 50°C.

Also, in the supercooling test, crystallization did not occur for 1 hour at -15q○. As described above, the liquid crystal composition of the present invention is superior to conventional liquid crystals in terms of temperature characteristics, stability, and display ability, and when made into a product, it can withstand use even in cold regions. Become.

A liquid crystal composition having such characteristics can be applied not only to the display parts of calculators, wristwatches, etc., but also to the display parts of various devices.

A prototype wristwatch was produced using the liquid crystal composition of the present invention, but there were no problems with various aspects such as lifespan and contrast.

Claims (1)

[Claims] 1. A compound whose structural formula is ▲There are mathematical formulas, chemical formulas, tables, etc.▼ ▲There are mathematical formulas, chemical formulas, tables, etc.▼ Compounds whose structural formula is represented by ▲There are mathematical formulas, chemical formulas, tables, etc.▼ Compounds represented by ▲ There are mathematical formulas, chemical formulas, tables, etc.▼ Compounds represented by ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Compounds represented by ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Compounds represented by and ▲There are mathematical formulas, chemical formulas, tables, etc.▼ A nematic liquid crystal composition characterized by consisting of a compound represented by the following.