DD160312A3 - APPLICATION OF NEMATIC LIQUID CRYSTALS - Google Patents

Abstract

The invention relates to the use of nematic liquid crystals in optoelectronic components for the modulation of light and for the representation of numbers, characters and images. The aim of the invention are nematic liquid crystals, which are well suited for optoelectronic arrangements, preferably for the two-frequency operation. It was found that pure or mixed 2-n-alkyl-1,4-bis- (4-acyloxy) -benzene of the general formula wherein R is high 3 = nC deep m H deep 2 m + 1 with m = 3 to 14 means are very well suited for use in optoelectronic devices.

Description

Application of nematic liquid crystals

Field of application of the invention

The invention relates to the use of nematic liquid crystals in optoelectronic components for the modulation of the transmitted or reflected light and for the representation of numerals, characters and images.

Character isti k of the known technical solutions

! Liquid crystals show due to their dielectric! Anisotropy is a special interaction with electric fields and can therefore be oriented, nematic liquid crystals with positive dielectric anisotropy are oriented parallel to the electric field, while those with negative dielectric anisotropy are oriented perpendicular to the field. Due to dielectric relaxation can in certain

1.5 'liquid crystals, which have a positive dielectric anisotropy at low frequencies, above the relaxation frequency a negative, dielectric anisotropy occur. Near the relaxation frequency (isotropic frequency), the dielectric anisotropy is Hull. It has already been proposed to make use of this effect in optoelectronic displays by operating the display with 2 frequencies (DD-WP 107 5oT).

This type of control allows a change both, the outward and the return time exclusively by changing the electric field strength, so that. that

Very slow decay of the dielectric information can be significantly shortened in normal operation. The previously known substances for this effect either have an uncomfortably high relaxation frequency (in the Ι, Είζ range), too high melting temperatures, or they are chemically and thermally unstable.

In the previously known 2-3ubst.-1, 4-bis - /! - acyl0x37-bensener

1.0 D »Bemus, H. Dennis, H. Saschke, liquid crystals in tables, VEB German publishing house for basic industry Leipzig 1.976, P. 84; , WP 106 933, 108 022, 1.08 023, 116 732, 13s 473, 139 575, 139 592; also AG Griffin et al. Mol. Cr. liqu. Gryst. J4, 267 (1978); TA Rotinjran et al. Krisca logr. 23, 578 (1978). the 2-substituents correspond to relatively small groups, for example R ^ = --Gl ₅ -CH ^, -G ₂ ^, -GJ, -OHpClT. These. Columns largely correspond to the classical ideas of the molecular structure of liquid crystals, ie they are substantially elongated. Lloleküle with rod-nformiger shape before. Due to their high relaxation frequency, these compounds are also unsuitable for two-frequency operation. That is why we are constantly searching for new substances which do not or only to a limited extent show these disadvantages.

^ O

2.5 Object of the invention

Object of the Invention Bind novel nematic liquid crystals which are well suited for electro-optic arrangements, preferably for two-frequency operation.

DISCLOSURE OF THE NATURE OF THE INVENTION The object of the invention is to provide nematic fluids

- 3

sige: crystals with low relay frequencies, low melting temperatures and good thermal and chemical stability.

It has been found that pure or mixed 2-n-alkyl-1,4-bis- / 4-acylsbenzenes of the general formula

R GOOhS) -OOC-R

1 2

R, R = Cf

> - '° η ^Η 2η ₊ 1 ° - <2) -' ⁰ Ii ^ i ₊ 1 ^0C0 ° -

with η = 1 to 16

- π-C IT

with m = 3 to 14

are very well suited for use in corresponding optoelectronic components.

The relaxation frequencies of nematic liquid crystals with positive dielectric anisotropy are shifted to low values by addition of these substances. The molecules of liquid crystals must, as already the investigations of Vorlander / "D * Vorländer, Chemical Crystallography of Liquids, Leipzig 1924_? As well as the entire recent literature /" D. Demus, E. Demus and H. Zaschke, Liquid Crystals' in Tables, VS3 Deutscher Verlag für Grundstoffindustrie, 2nd ed., Leipzig 1976 /, show, as long as possible elongated liolekülbau, In substances from the üyp of 2-subst.-1 4-bis- / 4-acyloxybenzones are therefore crystalline liquid only in the case of small 2-substituents. Characteristics to be expected, ss'is completely surprising that. the derivatives substituted in the 2-position with longer n-alkyl chains have crystalline-liquid properties, because the lolecule shape is no longer nearly rod-like in the compounds with a longer alkyl chain R.

Λ _

The second completely surprising feature is the high viscosity of these substances, as the following compilation shows:

CH

3 '

) -C E = ii

-OQO

'4 9

-ClT

Viscosity at 2.0 c St

30

1088

1-0 Hur due to these two surprising properties, the use of the substances according to the invention in displays with 2wefrerequenzansteuerung is at all possible and useful, because on the one hand, the substances must be nematic and on the other low 5.elas: a.tionsfrequenzen that come about by a high viscosity , own.

The substances according to the invention have good thermal and chemical stability and in some cases very low conversion temperatures.

Exercise games

20 Example 1

Tables 1 and 2 below show the transformation temperatures of some substances according to the invention,

-X-

S - 4 -

23

2-n-alkyl-1,4-

Table 1

= R

R-

CH ₃ O ° 3 ^Η 7 , 127 ♦ 135.5 CH ₃ O • 122-124.5 . (105.5) CH ₃ O C ₅ H ₁₁ , 98-100 ♦ (85) CH ₃ O ^C 6 ^H 13 , 90 to 91.5 ♦ (77) CH ₃ O C ₇ H ₁₅ , 81-82 . (70) CH-, 0 ^C 8 ^H 17 , 81-82 (67) .--- CH, 0 C ₉ H ₁₉ , 90-91 . (64-65) ^C 10 ^H 21 ♦ 83-83.5 . (60-61) /*t"f.T / * \ , 81 to 81.5 . (58) CH ₃ O ^G 12 ^H 25 • 89-90 (5-6) C ₂ H ₅ O C ₃ H ₇ , 150-153 , 155-156 Ο (TT I ^- N C ₄ H ₉ , 148-151 ( ♦ 130-131) C ₃ H ₇ O CH , 87-89 120 to 121.5 C ₃ H ₇ O , 109-111 ( , 99-100) AQ , 84-86 , 125.5 to 126 A. Q. C ₄ H ₉ , 104-105 , 110 C ₅ H ₁₁ O C ₃ H ₇ , 81-83 , 106 to 106.5 C ₅ H ₁₁ O ^C 4 ^H 9 , 85-86 .94 CgH ₁₃ O C ₃ H ₇ , 56-59 , 107 to 107.5 C ₄ H ₉ , 67-68 , 96.5 C ₆ H ₁₃ O ♦ 77-78.5 • 88 ^C 6 ^H 13 , '60 -61 , 83 , 59-61 , 79 to 79.5 CgH ₁₃ O C ₈ H ₁₇ , 66 to 68.5 , 77 C ₉ H ₁₉ , 66-68 , 76.5 C ₆ H ₁₃ O ^C 10 ^H 21 , 67-68 , 72

23 11 19

1st continuation Tab, 1:

R ¹ = R ² R ³ K Ή

, 69-71. 69

♦ 62-65. , 67

C ₆ H ₁₃ OC ₁₆ H ₃₃ . 58-61 ♦ 64-64.5

C ₇ H ₁₅ OC ₃ H ₇ . 56-58. 99

Q ₇ H ₁₅ OC ₄ H ₉ . 65-67. 90

C ₇ H ₁₅ OC ₅ H ₁₁ . 74-75. 83

C ₇ H ₁₅ OC ₆ H ₁₃ . 59-60. 79

ΊΟ ^σ 7 ^Η ₁₅ ° C ₇ H ₁₅ . 54-56. 75.5

C ₇ H ₁₅ OC ₈ H ₁₇ . 59-60. 74

C ₇ H ₁₅ OC ₉ H ₁₉ . 60-61. 73.5

C ₇ H ₁₅ OC ₁₀ H ₂₁ . 58-60. 69.5

C ₇ H ₁₅ OC ₁₁ H ₂₃ . 66-67.5. 67.5 '

-J ₅ C ₇ H ₁₅ O ^σ ₁₂ ^Η 25 ^{# β1} - ⁶¹ ' ⁵ · ^δ5 > ⁵

C ₇ H ₁₅ O ° 16 ^Η 33 * ^δ6 ~ ⁶⁷ (' ^δ2 )

C ₈ H ₁₇ OC ₃ H ₇ . 51-52.5. 97.5 to 98

C ₈ H ₁₇ OC ₄ H ₉ . 57-58 ♦ 91

C ₈ H ₁₇ OC ₅ H ₁₁ . 68-69.5 ♦ 84.5

C ₈ H ₁₇ OC ₆ H ₁₃ . 61-62. 81.5

C ₈ H ₁₇ OC ₇ H ₁₅ ♦ 52-53. 78.5

C ₈ H ₁₇ OC ₈ H _n . 57-58.5. 77.5

C ₈ H ₁₇ OC ₉ H ₁₉ . 65-67. 77

C ₈ H ₁₇ O ° 10 ^Η 21 * ⁵⁹ ~ ⁶ ° * ⁷⁴

C ₈ H ₁₇ OC ₁₁ H ₂₃ . 49-51.5 ♦ 72

C ₈ H ₁₇ O ^G 12 ^H 25 * ⁵⁵ ~ ⁵⁶ * ^{β9> 5}

C ₈ H ₁₇ O ^C 16 ^H 33 * ⁶⁵ ~ ⁶⁷ ' ^β9 ~ ⁶⁹ » ⁵

C ₉ H ₁₉ OC ₃ H ₇ . 49-51. 91 to 91.5

C ₉ H ₁₉ OC ₄ H ₉ . 58-61 -. 84-85

C ₉ H ₁₉ OC ₅ H ₁₁ . 64-66. 78 ·

C ₉ H ₁₉ OC ₆ H ₁₃ . 64-65. 76 to 76.5

C ₉ H ₁₉ OC ₇ H ₁₅ . 53-54. 73 to 73.5

C ₉ H ₁₉ OC ₈ H _{17 ο} 54-56. 72.5

i 23111

2. Continuation Tab, 1:

R ¹ = R ² R ³ K Ή

5 σ 9 ^Η 19 ° σ 9 ^Η 19 ° σ η 9 ^Η 19 ° TT Vv C 10 ^η 21 3 ^Η 7 10 C C 4 ^Η 9 C 5 11 6 ^Η 13 σ 6 ^Η 13 C 6 ^Η 13 15 C 6 ^Η 13 C 6 ^Η 13 C 6 ^Η 13 C 6 ^Η 13 C 6 ^Η 13 20 σ β ^Η 13 C 6 ^Η 13 σ 6 ^Η 13

C ₉ H ₁₉ . 60-61 .73

C ₁₀ H ₂₁ . 60-61. 70

C ₁₁ H ₂₃ . 52-53.5. 67.5

C ₁₂ H ₂₅ . 41-43. 66

C ₁₆ H ₃₃ . 64-66. 66 to 66.5

C ₃ H ₇ . 60-63. 92 to 92.5

C ₆ H ₁₃ . 63-65. (33 to 33.5)

C ₆ H ₁₃ . 59-62. (18-19)

C ₆ H ₁₃ . 31-33.5. 40.5 to 41

C ₃ H ₇ . 46-48. 51-52

C ₄ H ₉ . 54-57. (37-38)

C ₅ H ₁₁ . 48-51. (30-31)

CgH ₁₃ . 27-29. 28

C ₇ H ₁₅ . 44-45 (23.5)

C ₈ H ₁₇ . 48-49.5. (20.5-21)

C ₉ H ₁₉ . 52-53.5. (18)

C ₁₀ H ₂₁ . 56-56.5 · (17)

C ₁₁ H ₂₃ . 62-64. (15-15.5)

, 45-47. (15)

C ₁₆ H ₃₃ . 41-43. (15) ·

J ₇ H ₁₅ C ₃ H ₇ . 45-47 .60-62

C ₇ H ₁₅ C ₆ H ₁₃ × 18-19 × 40.5-41.5

25 C ₈ H ₁₇ COO C ₆ H ₁₃ . 70-72. 94-95

C ₈ H ₁₇ GOO C ₇ H ₁₅ . 78-79.5. 87-89

C ₄ H ₉ OCOO CgH ₁₃ . 79-82. 81-84

C _A H _g 0C00 C ₇ H ₁₅ . 63-65. 73-75

231 1 13 k

Table 2 2-n-alkyl-1,4-bis- / _> "" 4-n-pentyl-cyclohexanecarbonylosy_7-

R ² KH. I yield (%

G ₃ H ₇ . 58-58.5. 99-100, 57.0

C ₄ H ₉ . 59-60 .79. 51.4

C ₅ H ₁₁ . 64-65. 66.5-67. 46.5

C ₆ H ₁₃ . 41-43. 58.5 ♦ 38.1

-IO C ₇ H ₁ . ♦ 46-48. 52. 44.6

Example 2

High viscosities cause low relaxation frequencies of nematic liquid crystals.

Viscosities of 2-n-0ctyl-1,4-bis / ~ 4-n-octyloxybenzoyloxy _i _7-benzene (in a nematic phase V ¹ ^ ₁₎

t / ° C 25 56 64 76 ^ ₁ ZcSt 960 167 115 72

In comparison, the viscosity of 4-n-alkyloxy-benzoic acid 4- ^f -ii-alkylo2-yphenyl esters is smaller around the factor 10.

Example 3

Isotropiefrequenzen f a mixture of 60 mol% of 2-n ~ 0ctyl-1,4- "bis _J / ~" 4-n-octyloxybenzoylo2y_7 '-' benzenes and 40 mol% 4-n-0ctylozybenzoesäure-4- (ß cyanoethyl) phenyl ester:

t / ° C 20 25 33 48 f _o / kHz 8 16 47 250

The clearing point of the mixture is 68 ⁰ C. At room temperature is the smoldering! Voltage in jtfiederfrequenzbereich 2.5 V.

231119 4

Example 4

The mixture according to Example 3 is used in a cell of the following type: A thin layer (5 "to 30 / μm thick) of the liquid crystal is sandwiched between two glass panes which are internally provided with a transparent, electrically conductive layer (SnOp or In ₂ O ^) The array is placed between crossed polarizers, and at a voltage of 5 7/50 : Mz , the cell completely extinguishes the light, but at 5 V / 12 kHz, the transparent one is turned off Condition.

Claims (1)

231 invention claim 1. Application of nematic liquid crystals in opto electronic arrangements, preferably with two frequency control, characterized in that pure or mixed 2-n-alkyl-1 ^ - "- - ^ ^ oxy_7 ~ benzene of the general formula - OCC-R ^{2 C} n ^H 2n- ^{f 1 0C 0} ° - ^C n ^H 2n ₊ 1 ° with η = 1 to E ³ = nC _m H _{2m + 1} with m = 3 to be used.