JPS58142967A - Liquid crystal composition - Google Patents

Abstract

PURPOSE:To provide a liquid crystal composition containing specific ester compound and a chiral nematic liquid crystal at specific ratios, exhibiting quick responce even at a low voltage, having broad temperature and voltage margins and high chemical stability, and suitable for a liquid crystal light valve of a printer. CONSTITUTION:The objective composition is composed of (A) a mixture of ester compunds comprising 40-60wt% compound of formulaI(R and R' are 1-8C straight-chain alkyl), 0-20wt% compound of formula II, 0-20wt% compound of formula III, 5-20wt% compund of formula IV and 0-15wt% compound of formula V and (B) 0-5wt% chiral nematic liquid crystal. A liquid crystal panel suitable as a liquid crystal light valve for the optical ON-OFF control can be manufactured by inserting the liquid crystal composition between a pair of oppositely placed glass plates each having a NESA electrode at the inner side. The ON-0FF control can be carried out by applying a signal containing a component having higher frequency than the cross frequency (fc) of the liquid crystal material and a signal containing lower frequency component than fc.

Description

[Detailed Description of the Invention] Zero-IllJ is a liquid crystal material that is sandwiched between liquid crystal panels.
A liquid crystal light pulp Kll that performs optical ON-OFF control is applied by applying a signal of a dynamic amount frequency component to e and a higher local frequency component to sfe. More specifically, by using a new liquid crystal shrinkage eyelid, the photoresponsive link Wl of the wrinkle panel
th-A very durable liquid crystal composition.

In recent years, information processing has been rapidly increasing in capacity, high-speed calculations, and OA (office automation)-like equipment has become popular. Printer 4, which is one of the terminal devices of
, high speed, high print quality, I! However, at present, there is no product on the market that satisfies these requirements, and its release is highly desired.

By applying electrophotographic technology to the LCD light pulp sound and light No. 4II generation part, the circle mark zero # t (Ill) 1111 @5
6-95568) ij The above points have reached a practical level and are attracting attention.

First, an outline of the configuration of the above-mentioned liquid crystal light pulp type printing apparatus is shown in FIG.
Included. At this time, the photosensitive drum 102 is charged in advance by a corona charger 110. At this time, when printing characters, the optical signal is usually such that light is generated corresponding to the character part. This K forms an electrostatic latent image, which is developed with toner by the magnetic brush MS unit 103. The development method used at this time is usually an anti-button process. The toner is transferred onto plain paper 104 by the transfer corona discharger 105 and fixed by the fixing device 106 . On the photosensitive drum after transfer! ! ! The residual toner is inspected by the blade 108, and the electrostatic latent image is neutralized by the neutralizing lamp 109, and the process ends.

Figure 2 shows the configuration of the optical signal generating section.The light emitted from the light 9201 is 0y-oy
y control, and the transmitted light is distributed Km on the photoreceptor by the condensing lens 221. Two polarized LCD panels $211
K is assembled with K, and glass plate 212 is evaporated, sputtered, and coated with DP@. 215, liquid crystal alignment control film 2
16 10, liquid crystal 2 by seal 217 and liquid crystal panel
Holding 18 in between.

The 5th s is a front view of the liquid crystal panel, and the light transmission value IF+
Micro Sharita group 302 and constant light III
It is more intimidating than the light mask Iku 301 who does i+.

Next, the driving principle of Km crystal light pulp will be explained.

Hall 41m shows signals applied to the liquid crystal panel and transmitted light characteristics. 4JAL, the case shown here is one driven by a single dynamo. When a signal with a higher frequency component than the liquid crystal Kfc is applied for a period of 〒1 (No. 4 @ 6)), the panel transmits light (Fig. 4 a).
] When four fet-like low frequency components are applied to the 00th order K11l for a period of 1Thf1, the panel emits light! The island is a selection period, and in this case, it is de-tei & t! */Ts. It is already known that the alignment state of liquid crystal molecules can be controlled by the frequency of the signal applied from this side.11 In order to satisfy this requirement, the characteristics must be adjusted in detail, depending on the light source optical system around the panel, and the driving method. Although some improvements are possible, much depends on the basic characteristics of the liquid crystal.

In order to realize excellent liquid crystal light pulp, the basic properties required of liquid crystal materials are as follows! I is raised.

t High-speed response with low voltage.

2.Ii! I. Wide voltage margin.

3. High reliability.

The details of this phenomenon will be omitted, but this phenomenon is based on the property that the sign of the dielectric anisotropy of the liquid crystal is inverted depending on the frequency of the applied signal. FIG. 5 shows the frequency dependence of the dielectric constant -q in the major axis direction and the dielectric constant in the minor axis direction of liquid crystal molecules. At the crossing frequency fe (frequency where 8g = -), the sign of the -electrotropy Δ is reversed. J) Above, the driving principle of the liquid crystal light pulp is explained, and 9 shows that when this liquid crystal light pulp is used for the memorandum of the printing device, the high speed, high printing quality of the printing device, and the high confidence Ill. In order to achieve the 11th generation, many constraints must be met.

First, it is necessary to supply a high amount of energy to the photosensitive drum within the writing time (41% QTm).Liquid crystal materials for dual-frequency driving have been previously researched for use in displays. There are some excellent FLs available, but they require extremely high-speed response (less than a few milliseconds), like the liquid crystal light pulp used in the Indian Army's scissors. Liquid crystal material Fi that satisfies all the characteristics
Ama-Sho Unknown - The present invention improves the characteristics of the liquid crystal material for liquid crystal light pulp used in printing devices, etc., and its purpose is to provide high-speed response at low voltage. .

2. Wide Ill/voltage margin.

5. Ensure high reliability.

It is an object of the present invention to provide a liquid crystal material for dual-frequency driving that satisfies the above requirements in a well-balanced manner.

Below, an explanation will be added about these rtg request 3JI@.

・T High-speed response with low voltage.

The helmet has been changed to a ho, and for low cost, no work is required on the drive circuit.
If a cape is used, the driving voltage and the number of driving cycles are limited by 111. 1! In order to reduce power consumption, low voltage and low frequency are desirable, and the response of the liquid crystal is
As shown below, since the square of SW anisotropy is inversely proportional to the square IIK, K to obtain a high-speed response must increase the absolute value of the dielectric anisotropy at the driving frequency! There is. In addition, low viscosity is also a cost consideration. Since the WK drive frequency cannot be made too high, the FE of the used ILW must also be increased accordingly.

There is no liquid crystal material that satisfies these requirements with a single component, but it is necessary to combine the tube number component to satisfy the characteristics with a good panacea. However, these two have contradictory properties in terms of I%/%.Among the components in the composition provided by the present invention, R-4)-coo- @-OR' (However, R0R
'1 to 8 is the level for the viscosity of the composition.
It has the property that f<.

Next, there is a component that adjusts the zero dielectric anisotropy at low frequencies, and a component that adjusts the dielectric anisotropy at high frequencies.
) @crystal, there are many metal compounds with a molecular structure similar to that of liquid crystals, which have a large positive dielectric anisotropy or large blockage, but those with a large absolute value of negative dielectric anisotropy. There are very few* l' K Fi, both IKI! p1/1″1. Melting entropy is a quibble, liquid crystal temperature range is wide,
Furthermore, if we impose constraints such as not having an effect on Kti, fe, or viscosity, the types will become even more important. It has a very large dielectric anisotropy and a low fc4.Furthermore, among the components of the composition, the absolute value of the dielectric anisotropy of the food is large and the other components It also has excellent compatibility with

Next, regarding chiral nematic liquid crystal, which is one of the components of the composition provided by the present invention, in the case of a display panel, a small amount of a scissors component is added to prevent reverse tilt, and it is suitable for guest-host display. 4IIl to improve contrast”
In addition, by applying the memory effect of the wrinkle-distributed liquid crystal, the 4F-1 of this component is known. It is also well known that the response speed is improved by using the return force to the structure.In the present invention, the nematic liquid crystal added in the present invention has the same effect as the improvement even in the two-round driven system. In other words, it has the effect of improving response speed.
Driving with a signal having a relatively high frequency component, that is, when aligning the liquid crystal molecules square to the 7-plane plane, has the effect #1 of increasing the speed by %.

The present inventor, Misaki, achieved ΔB1 by combining the above-mentioned O components in an appropriate ratio. It is possible to increase the absolute value of Δ-(conventionally 1>@acids, it was difficult to increase the absolute value of Δ-iris when considering the relationship with other 41-). Furthermore, by adding chiral nematic liquid crystal, we were able to significantly improve the response time during usage and voltage.

In the case of liquid crystal compositions, it is expected that the interaction between different components, which is different from that of a single component, will have a considerable influence on the viscosity mf's and therefore on the response speed. Even if the composition provided, this interaction is as fljl! It seems that Japan is working in the direction of reforming the Emperor, and I look forward to IO research for a physical or quantum mechanical interpretation of this point.

The above is the main reason for using the ingredients according to the present invention to prepare 411411.

2. Sehen/voltage i-jin is a slender.

First, regarding the margin, Figure 6 shows the leakage dependence of the dielectric anisotropy of the liquid crystal. Dielectric anisotropy at frequency. So that everyone can understand△
- As FiIllf increases, it decreases rapidly. Although there are some differences in this tendency depending on the liquid crystal, it is a basic characteristic of liquid crystals, so when actually using it, it is best to choose an ia** finish with a small amount of Δ-t conversion. First, as in the case of the present invention, if the response is required to be very fast, it is necessary to lower the viscosity of the liquid crystal in a certain 11 degree high temperature range. It is undeniable that Δ■ will be working full-time in this transition to KIlIt.
Furthermore, in order to have a wide variation margin, the light transmittance of the liquid crystal should be 41N! # It is necessary to adopt a saturated range. That is, under a constant voltage, the response is continuous and the light transmittance is saturated, and it is a prerequisite that the above-mentioned characteristic 1 is satisfied. Further, the voltage margin can be considered in the same way.

4. Ensure high reliability.

Regarding the chemical, optical or electrochemical stability of liquid crystals.
The liquid crystals according to the present invention are all ester-based liquid crystals and have high optical reliability, and due to the accelerated aging cape, reliability #
/i-iku is different from the biased opinion that it is at the level of a collection.

With the aim of clearing the above-mentioned 1 and 2.5 levels in a well-balanced manner, this project aims to clear the above-mentioned levels of 90% and 100% by appropriately selecting the acid content 0 ratio of each of the above. It is possible to create a liquid crystal material with the characteristics t1wtt, that is, as shown in 1IIK.

[In the above description, R and R' represent straight-chain alkyl having 1 to 8 carbon atoms.] 111 Next, the details of the present invention will be explained with reference to examples.

Prepare the liquid crystal composition listed in Example 2 and examine its basic characteristics and light transmittance characteristics.

12 [HIY has the structure of 12] No. 711 K112 shows the frequency dependence of the dielectric constant of the liquid crystal oxide, provided that II constant temperature is 30°C.

This liquid crystal was sealed in a test cell with a cell thickness of 5js, and a low frequency signal (SO'?, 1111g) and a high frequency signal (30V) were applied.

1! Soi! ! #) I have already carried out Maina R Sugayu drive, and the 811th KII was shown in Figure 0, which shows the light transmittance characteristics.
naac, repeated responses are possible during the opening time α5~shiige. The rubbing angle of the cell used at this time was 70@, the polarization directions of the polarizing plates sandwiching the cell were at an angle of *, and the constant temperature was 40°C.

Next, a printing experiment was carried out using this liquid crystal light pulp, and the liquid crystal cell was adjusted the same as described above.
I: A high-intensity variable fluorescent lamp using a Tb''+ phosphor was used, and a B# sensitized with a photoreceptor K11 was used.

As shown in No. 180, each part was moved once, the S surface sm*pz of the photosensitive drum ran at 5aa/age, the liquid crystal was driven by a liquid crystal, and the optical writing was performed. Liquid crystal-acid is one example, and even if each component is replaced with its homolog, the blending ratio of the compounding ratio 0III in the decline as described in the range of blending ratio claims @IK! The present inventor has conducted experiments to find that excellent characteristics similar to those of this embodiment can be achieved even if the present invention is used within I, so the present invention is not limited to this embodiment KIII*. .

Corresponding to the 0N-01ν, by forming a clear meeting, the #0 main dormitory example is an example of the use of the liquid crystal light pulp provided by the present invention. Optical writing-x*t can also be applied to displays.

As mentioned above, the present invention utilizes the dielectric dispersion of liquid crystal,
By using a liquid crystal light pulp that performs printing and high-speed switching using two-frequency drive, we succeeded in improving the responsiveness of the liquid crystal. The effects of the present invention are great because the voltage margin etc. have been dramatically improved.

L! l! Brief explanation of 1lWj 5111111 [Structure of crystal light pulp type printing mold - Ink.

No. 211 is a schematic diagram of liquid crystal light pulp.

No. IWA is a top view of the liquid crystal used in liquid crystal light pulp (flannel).

The 411th signal is the signal applied to the liquid crystal light pulp and the photoresponse characteristics at that time.

Fifth! l is the frequency characteristic of the dielectric constant of the liquid crystal.

The sixth factor is the thermal properties of the dielectric anisotropy of liquid crystals.

The seventh @ is the frequency characteristic of the dielectric constant of the liquid crystal compound used in this embodiment.

IIIa- is book l! Photoresponse characteristics of liquid crystal light pulp according to an example.

that's all Figure 1 a) Figure 2 Figure 3 Side.

seven Figure 4 5th m Figure 7 11-1-C) Figure 8

Claims (1)

[Claims] Two glass plates having Nesa Den Il inside are made to face each other,
Meanwhile, the KW1 crystal material is held between the two sides, and a signal with a higher frequency component (lower than the intersection frequency c of the liquid crystal material, abbreviated as fc) and a signal with a lower frequency component than the S/C are sent to the LCD panel as a single signal. When applied in a superimposed manner, the light is transmitted! ! In the liquid crystal composition controlling TIIIF, it is preferable that the liquid crystal material has a composition like T1. In the upper 5ell, R and R' have 1 to 6 carbon atoms.
[represents a straight chain alkyl]