JPS58142959A - Liquid crystal composition - Google Patents

Abstract

PURPOSE:To provide a liquid crystal composition containing specific ester compounds and a chiral nematic liquid crystal at specfic ratios, exhibiting quick responce even at a low voltage, having broad temperature.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 compounds 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% compound of formula IV and 0-15wt% compound of formula V (group of formula VI is formula VII or formula VIII) 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-OFF 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 The present invention provides nine liquid crystal materials that are held in a liquid crystal panel! It is related to the liquid crystal light valve κ that performs optical ON-01'ν control, applying to the signals of the low frequency component (#) and the high frequency component (f). More specifically, the present invention relates to a liquid crystal light pulp in which the photoresponse speed of the Kyop1 scissor panel is made extremely high by using a new liquid crystal composition.

Recently, the information department has increased in capacity, high-speed calculations, and 0▲(
The popularity of office automation equipment is rapidly progressing. Printers, which are one of the 0▲ terminal devices, are required to be high speed, print quality, and low price, but there is currently no product on the market that satisfies these requirements. , O-outa is strongly desired.

A printing device (Japanese Patent Laid-Open No. 56-93868) using a liquid crystal Twitbulb as the optical signal generating section and applying electrophotographic technology has been attracting attention since it has reached a practical level as mentioned above.

The outline of the configuration of the above-mentioned 0@crystal twin-bulb type printing device is shown in Figure 111, and a %A nine-light signal generator 101 for ill flight pulp performs memorization on the photosensitive drum 10m. At this time, the photosensitive drum 102 is charged in advance by a corona charger 110. Normally, when printing characters, light is generated corresponding to the part of the characters. This K forms an electrostatic latent image, which is developed with toner by a magnetic brush developer 103. The development method used for the development is usually reversal development. After transfer, the toner is transferred to plain paper 104 by Rona Denki 105,
The image is fixed by the fixing device 106.

The nine F toner remaining on the photosensitive drum after transfer is the blade 108.
The electrostatic latent image is then removed by the static eliminating lamp 10G and the process ends. No.! The light source 201, which shows the IJL IkuO configuration from the IIK Kouyu issue, is the liquid crystal panel II (211 to 21).
11) “1”0N-07? The transmitted light is imaged onto the photoreceptor by the condenser lens 2'1lIK. The liquid crystal panel is sandwiched between two light plates 211, and the glass plate 2
12 (by vapor deposition, sputtering, dip coating, etc.), or further by photoetching]. Metal thin II214 used as optical I-sk, insulation J
l1215, Il crystal orientation control film 216
'-J) N Seal 2 The liquid crystal 21g is held between the i7 and the liquid crystal panel.

Figure 3 is a front view of the liquid crystal panel, which consists of a group of micro shutters 302 that transmit and block light, and a light mask 301 that always blocks light.

Next, the driving principle of K11m1 light pulp O will be explained.

No. 411 shows signals applied to the liquid crystal panel and transmitted light characteristics. However, the symbol ζζ applies to the case of dynamo-built-up drive. Fayoru bird on the LCD #l1Ik
A signal containing a component is applied for an opening period of 1 to 1 (11
114), the panel transmits light [No. 4116)]
0th order to the liquid crystal /l] signal with low frequency components!
When applied for IO, the panel blocks the light (C 4th diagram).

Ts is the selection period for purchasing], and in this case, DT is TE/? − becomes. It is already known that the arrangement of liquid crystal molecules can be controlled by the frequency of the applied signal, so the details are omitted, but this phenomenon is caused by the sign of the dielectric anisotropy of the liquid crystal depending on the frequency of the applied signal. [based on] the property of reversal. FIG. 5 shows the dielectric constant '11 in the long axis direction of the liquid crystal molecule and the frequency characteristic of the dielectric constant #10 in one direction. The sign of the one trout anisotropy ΔC is reversed at the crossing frequency /a (frequency II which becomes 1xt-#i).

The above is an explanation of the driving principle of liquid crystal light pulp O. When using liquid crystal light pulp in the optical writing part of a printing device, high speed, high printing quality, and long-term compensation chain performance of the printing device can be achieved. In order to
In other words, the first thing you need to do is write it down ($114!
(2) During this period, a large amount of light energy must be supplied onto the photosensitive drum.

In order to satisfy this requirement, it is of course possible to improve the characteristics once depending on the light source optical system around the panel and the drive method, but it will take a long time depending on the basic characteristics of the liquid crystal. . In order to realize an excellent liquid crystal light pulp, the basic properties required of a liquid crystal material include the following OX items.

1. Jin and high-speed response with low voltage.

2. Wide temperature and voltage margins.

3. Must be able to ensure high Confucian characteristics.

Liquid crystal materials for dual-frequency drive have been researched for use in displays, and excellent performance has been achieved; However, research has revealed that there is a liquid crystal material that satisfies all of the above characteristics.
>unknown.

The characteristics of the liquid crystal material for liquid crystal light pulp used in the present invention aa and printing equipment * have been added], and so on.
1 catch is ! , high-speed response at low voltage.

2. 11 degree fist voltage! -Jin is wide with Jin.

3. A high level of credibility can be ensured.

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, we will explain these requirements.

1. High-speed response with low voltage.

The ninth part of the complete product, low cost, 'drive circuit KZ
When using c, etc., the driving voltage, driving voltage, etc.
is restricted. Further power consumption reduction: Rounding is inversely proportional to the square root of the tip angle, and in order to obtain high-speed response,
It is necessary to increase the II electroisotropy pair value. It is also required that the viscosity is low. Furthermore, since the driving frequency cannot be increased, f- at the operating temperature must also be lowered by an appropriate mK. A liquid crystal material that satisfies these characteristics with a single component can be made into a single material, while a liquid crystal material that satisfies each characteristic in a well-balanced manner can be created using multiple components. ★To adjust the zu, fa, and viscosity, these two have the properties of being in phase with each other.Among the components in the composition provided by 0, R-@-Coo+OR' (E) Dashi It, R1
represents a straight chain R-ecOo-4I alkyl having 1 to 8 carbon atoms 0
M has a composition of 0/# and a viscosity that are both below practical levels and have derogatory properties.

Next, there is one component that adjusts the electroisotropy of OIl at a low frequency, and one component that adjusts the electroisotropy of OII at a high frequency.
is a known liquid crystal or a compound having a molecular structure similar to a liquid crystal, and #i of 4 has a large absolute value of positive #electrotropy.
There are many examples, but the absolute value of negative hyperelectric anisotropy is 111/%.
There are very few O's. Furthermore, in both cases, if we add constraints such as low melting entropy, wide liquid crystal temperature range, and strong influence on fa, viscosity, etc., the types are even more limited ( Among the components of the composition provided by @, 11+COO-@-Coo-qCM [where l'1til represents a straight-alkyl having 8 carbon atoms] has a highly positive dielectric anisotropy. Large, low tefe,
★Excellent O compatibility with other ingredients.

It-(()-)400%30OR' (However, R represents a straight chain alkyl having 1 to 8 legs* represents either one of them.] has a very high absolute value of negative 0-electroelectric anisotropy, and is also excellent in 08flj properties compared to other components.

Next, regarding the chiral nematic liquid crystal in component O of the composition provided by the present invention! For summer display panels, a trace amount of wrinkle component can be added to prevent reverse tilt.p1
Use for guest host display to improve contrast
There are many known examples of using scissors components, such as kD, and further, by applying the memory effect of scissor component-added liquid crystals, such as nine display methods. Goose *&
In addition, it is well known that the response speed is improved by utilizing the helical force of chiral nematic liquid crystal, that is, the N force on the helical structure. The driving method also has the same effect as described above, that is, the effect of improving response speed. In the two-frequency drive system, Z a j
p When driven by a signal having a high frequency component, that is, when liquid crystal molecules are aligned square to the cell surface, 411
K has the effect of adjusting the speed accordingly.

The inventors of the present invention have determined that by blending the above-mentioned O components in appropriate proportions, the absolute value of Δ-&, Δ8-rich (41%) can be increased by increasing the absolute value of Δ1110 in conventional compositions. However, by adding chiral nematic liquid crystal, we were able to significantly increase the response speed at operating temperature and voltage. , in the case of liquid crystal compositions, □ viscosity,! -1 It is expected that this will have a considerable effect on the response speed1
This interaction seems to be working in the direction of improving the 041 properties of the relatives provided by the present invention, but the physical or nuclear explanation of this point remains for future research. expect.

The above are the reasons why the component according to the present invention is used for rounding the characteristic l to the nearest nine.

2. Wide temperature and voltage margins.

Regarding the temperature margin, Figure 6 shows the temperature dependence of the dielectric anisotropy of liquid crystal. In the figure, ΔCL indicates O dielectric anisotropy at a low shoulder line drive frequency, and Δ#K indicates OIl electrical anisotropy at a high frequency drive frequency. ail) As you can see, Δ
11 decreases rapidly as the temperature rises. Although there are some differences, this is the basic tenacity of liquid crystals, so when actually used, the temperature range where the amount of change in Δ1 is small is required. As in the case of this Ii@, when it is necessary to make the response very fast, it is necessary to lower the viscosity of the liquid crystal O in a certain high temperature range. Considering the undeniable fact that Δ1 fluctuates quite a bit due to temperature changes, and in order to widen the temperature margin, it is necessary to consider the range within which the light transmission characteristics of the liquid crystal are saturated. This means that under a constant voltage, the response is appropriate and the light transmittance is saturated], and it is a prerequisite that the above-mentioned characteristic 1 is satisfied. . can be considered similarly for the nine voltage margins.

3. Must be able to ensure high credibility.

Many studies and experiments have been conducted on the chemical, optical, and electrochemical stability of liquid crystals.

Iku Moto's liquid crystal is an ester-based liquid crystal with a pan.
Optical Confucianism is a bug<, also due to accelerated aging 41)
, the reliability is at a sufficient practical level, which is contrary to the opinion @.

Aiming at achieving the above-mentioned nine properties 1 and 1.8 in a well-balanced manner and at a practical level, the present invention aims to provide a composition with excellent properties by appropriately selecting the blending ratio of the above-mentioned 4) components. It is possible to make a liquid crystal material using a composition as shown in Table IK. ' [However, in the above table, the number, A' represents a linear alkyl group having 1 to 8 carbon atoms, and (-0-) in the structural formula
÷ represents one of the stands,] II- Next, the details of the present invention will be described in detail with examples.

IIIIIIA Example Prepare the liquid crystals listed in Table 2 and examine their fi1 characteristics and light 11AIIllNIIi.

Table-2 [C? H1, has the structure of 1 ■] Figure 7 K11l! The frequency dependence of the dielectric constant of the liquid crystal composition shown in Figure 2 is shown, where the constant temperature is ℃.

This liquid crystal was sealed in a test cell with a cell thickness of 5 mm, and a low frequency signal (30 mA, IIcH liao) was used to compensate for high waste waves. (30 ma,
130K! When wheel dynamic drive was performed with Is), the light transmission characteristics shown in item 811 were exhibited.

As shown in the figure, in die chuck drive, the return cycle is 2w.
Lama, day time 0.5-0.6 sag-deku) return response is possible. However, the two-pin angle of the cell that could be used at this time was 700, the polarization directions of the polarizing plates O sandwiching the cell were perpendicular to each other, and the SW constant temperature was 40c.

Next, a printing experiment was carried out using this liquid crystal light pulp, and the liquid crystal cell was the same as the above-mentioned 0III cell, and the driving conditions were also the same. The light source has a structural formula, CgMgmuj□0
□s: High brightness fluorescent rung using Tim+ fluorescent material,
For the photoconductor, use Qi sensitized and 9S-.

Each part was arranged as shown in No. 111K, and the surface movement speed of the photosensitive drum was Sey'ama. Drive the liquid crystal light pulse and perform optical writing.
This embodiment is an example of the use of the liquid crystal light pulp provided by the present invention, and is compatible with YK and forms a clear image. , it can also be applied to displays, etc.

The liquid crystal composition that can be used in this example is just one example, and even if each component is replaced with a homolog of the component, the blending ratio may be changed to the blending ratio in the table described in claim S. The present inventor has conducted experiments to realize that excellent properties similar to those of this example can be achieved even if the value is within the range of Now, an umbrella.

As mentioned above, in the present invention, dielectric dispersion of liquid crystal is used,
In liquid crystal light pulp that uses three-frequency drive and high-speed switching, we succeeded in improving the responsiveness of the liquid crystal material, and in practical use, we also improved the writing speed, temperature, voltage margin, etc. of the printing device. The effect of the present invention is significant because of the improvement.

Simple drawings tkims The first ml is between the structures of a liquid crystal light pulp type printing device.

The second WJ is a schematic diagram of liquid crystal light pulp.

FIG. 3 is a top view of a liquid crystal panel used for liquid crystal light pulp.

FIG. 4 shows the signal applied to the liquid crystal light pulp and its dark light response characteristics.

FIG. 6 shows the frequency characteristics of the dielectric constant of liquid crystal.

Figure #16 shows the temperature characteristics of dielectric anisotropy of liquid crystal.

FIG. 7 shows the frequency characteristics of the electrical conductivity of the nine liquid crystal compositions OII used in this example.

FIG. 8 shows the photoresponse characteristics of the liquid crystal light pulp according to this example.

that's all Figure 3 f! Figure 54 Figure 5 Figure 7

Claims (1)

[Claims] Two O glass plates having electrodes on the inside are placed facing each other, and a KIl crystal material is sandwiched therebetween, so that the cross frequency (hereinafter abbreviated as FA) of one liquid crystal material is higher than that of one liquid crystal material in nine liquid crystal panels. It is better to apply a signal with a frequency component and a signal with a low frequency component (f) singly or in a superimposed manner. A liquid crystal composition characterized by having a composition as follows. [9] In the above table, It and R' represent 1 to 1 carbon atom.
Represents a straight chain alkyl having 8 alkyl atoms. In the structural formula (-0
-) represents either ÷o or 10-.