100 Years of Liquid Crystals at Merck

1. 100 Years of Liquid Crystals at Merck
Dr. Peer Kirsch
Merck KGaA, Liquid Crystals Division, D-64271 Darmstadt, Germany
20th International Liquid Crystal Conference (ILCC-20), Ljubljana, Slovenia, July 4-9, 2004

2. H F F
F
R
H O F
H
Active Matrix Display (AMD) R OEt F
commercial production: 1989 H F
F F
concept: B. J. Lechner, 1971 H
R F
H
“Super Fluorinated Materials” (SFM), 1985 F
Super Twisted Nematic (STN) R CN R. Eidenschink et al., 1976
T. J. Scheffer et al., 1984
O CN
R D. Demus et al., 1975
Twisted Nematic Mode (TN) O
M. Schadt, W. Helfrich, R CN G. W. Gray et al., 1972
J. Fergason, 1971
O RO
Dynamic Scattering (DSM) RO N N R
R. Williams, G. Heilmeier, 1962 N R
H3C
H3C H
H H
PhCOO
F. Reinitzer, 1888

3. Vertical Alignment (VA) LCD TV
commercial production: 1998 2002
In Plane Switching (IPS) Cellular Phone 2000
commercial production: 1996
PDA
Active Matrix Display (AMD)
commercial production: 1989 Desktop PC Monitor
concept: B. J. Lechner, 1971
1997
Super Twisted Nematic (STN) Notebook PC
T. J. Scheffer et al., 1984
1990 1995
Twisted Nematic Mode (TN)
M. Schadt, W. Helfrich,
Wristwatches
J. Fergason, 1971
Pocket Calculators
Dynamic Scattering (DSM)
R. Williams, G.Heilmeier, 1962
1973

4. The Pioneers - 1
F. Reinitzer (Prague), 1888
H3C
H3C H
O
H H
O
C 145 N* 179 I
F. Reinitzer, Monatsh. Chem. 1888, 9, 421
Dr. Peer Kirsch ILCC-20 Page 4

5. The Pioneers - 2
O. Lehmann (Karlsruhe), 1889
• "Apparently living crystals" are
mesophases: a new and
distinct state of matter
• Lehmann asks Merck in 1904
to provide liquid crystals for
research
Dr. Peer Kirsch ILCC-20 Page 5

6. The Pioneers - 3
D. Vorländer (Halle), early 1900s
• Systematic study on various
calamitic liquid crystals
O
O N
N
O N
N
O
p-Azoxyphenetole
Dr. Peer Kirsch ILCC-20 Page 6

8. Milestones in the History of Merck
1668
Friedrich Jacob Merck
(1621–1678) buys the
“Engel-Apotheke”
(Angel Pharmacy) in
Darmstadt, Germany
1827
Emanuel Merck
(1794–1855) starts
production on an
industrial scale
Dr. Peer Kirsch ILCC-20 Page 8

9. International Successes and
Setbacks
• On the basis of the international
success, local subsidiaries were
established in
- London (1883)
- New York (1887)
- Moscow (1899)
• The New York branch evolved
into an independent US
Factory in Darmstadt, 1898
company after the World War I:
Merck & Co.
Dr. Peer Kirsch ILCC-20 Page 9

10. Merck Today
• Merck groups its operating
activities under Merck
KGaA, going public in 1995
• Shareholders hold 26% of
the total capital, the Merck
family holds 74% through
E. Merck as the general
partner.
Factory site in Darmstadt, 1995
Dr. Peer Kirsch ILCC-20 Page 10

11. Merck Enters Liquid Crystal
Business
• Since 1904 sale of reagents
for liquid crystal research:
– (Alkyl)ammonium oleates
– Cholesterol esters
– p-Azoxybenzoate
– p-Azophenetole
– p-Azoxyphenetole
– p-Azoxyanisole
Dr. Peer Kirsch ILCC-20 Page 11

12. The Skeptics
"Soft crystals do exist, floating ones
may exist, but liquid ones? I tell
you, no way!"
G. Tammann, around 1920
Dr. Peer Kirsch ILCC-20 Page 12

13. Thermochromic Cholesterics:
Applications
• Use of cholesteric liquid crystals as temperature indicators
since 1966, e.g., for
– Medical diagnostics: mammography, vascular disorders
– Non-destructive testing: welds, electric circuits
– Radiation sensing: IR, microwave
– Decorative: beer labels
Dr. Peer Kirsch ILCC-20 Page 13

14. Thermochromic Cholesterics:
Materials
• Cholesteric mixture systems TM74A/B and TM75A/B
(BDH Chemicals Ltd., Poole, UK):
O H3C
R
O *
O H3C
R
O H3C O *
RO
O *
• Thermotropic devices:
– Dispersion of microencapsulated cholesterics
– Polymer-dispersed cholesterics
Dr. Peer Kirsch ILCC-20 Page 14

15. Dynamic Scattering Mode (DSM)
• Developed since 1963 by R. Williams and G. Heilmeier
(RCA)
• Presentation in 1968 at the ILCC-2, Kent, OH: Motivation
for Merck to enter liquid crystal research
pictures: George Heilmeier with
DSM prototype (left), F. Vögtle,
Supramolekulare Chemie (right)
Dr. Peer Kirsch ILCC-20 Page 15

16. Dynamic Scattering Mode:
Materials
• Schiff Bases (Eastman Kodak)
RO R = CH3: MBBA
N C4H9 R = C2H5: EBBA
• Azoxy Compounds (Merck)
O
MeO N MeO N
N C4H9 N C4H9 N4
O
• Esters (Merck)
O
H7C3
ME-35
O C5H11
Dr. Peer Kirsch ILCC-20 Page 16

17. Practical Problems with
First Generation Materials
• Azoxy Compounds: Sensitivity against light
O
RO N
N R
• Schiff Bases: Hydrolysis and transimination
R1O
2
N R R1O R1O
2 4
N R N R
R3O
4
N R R3O R3O
4 2
N R N R
Dr. Peer Kirsch ILCC-20 Page 17

18. The Twisted Nematic (TN) Mode
• Invented in 1971 by M. Schadt and W. Helfrich (Hoffmann-
La Roche), and J. Fergason (Kent State University)
off on
picture: TN display prototype presented to
the board of directors at Hoffmann-La
Roche in March 1971
Dr. Peer Kirsch ILCC-20 Page 18

19. Liquid Crystal Production Merck Darmstadt (tons)
0
20
40
60
80
100
120
140
160
180
19
70
Dr. Peer Kirsch
19
72
TN
19
74
19
76
19
78
19
80
VIP
19
82
19
84
STN
19
86
19
88
ILCC-20
TN-TFT
19
Year
90
19
92
19
IPS
94
19
96
MVA
19
98
20
00
PALC
20
Liquid Crystal Production at Merck
02
20
04
20
06
20
08
prognosis
Page 19

20. Cyanobiphenyls and Terphenyls
• Developed by G. Gray and coworkers (Univ. Hull) in 1972
• First chemically and photochemically stable materials with
a nematic phase around room temperature
• Put to the market by BDH Chemicals Ltd. and Hoffmann-
La Roche
H11C5 N K15: C 23 N 35.1 I
∆εvirt = 21.6
H11C5 N T15: C 131 N 239.9 I
∆εvirt = 20.2
Dr. Peer Kirsch ILCC-20 Page 20

21. BDH Chemicals Ltd., Poole
• Since 1972 sales of liquid crystal
mixtures together with Merck
• In 2001 opening of Chilworth
Technical Centre
Dr. Peer Kirsch ILCC-20 Page 21

22. The Cyclohexane Substructure
• D. Demus and coworkers (Halle) in 1975
O N
H11C5
O
D5: C 47 N 78.7 I
∆εvirt = 14.8
Dr. Peer Kirsch ILCC-20 Page 22

23. Phenylcyclohexanes
• Developed by R. Eidenschink and coworkers (Merck) in
1976
H11C5 N PCH-5: C 31 N 54.6 I
∆εvirt = 17.9
H11C5 N BCH-5: C 96 N 219.3 I
∆εvirt = 17.2
H11C5 C3H7 CBC-53: C 54 SB 237
SA 260 N 317 I
Dr. Peer Kirsch ILCC-20 Page 23

24. Cyclohexylcyclohexanes
• R. Eidenschink (Merck), 1979
H
H11C5 N
H
CCH-5: C 67 SB (52) N 86.2 I
∆εvirt = 8.3
Dr. Peer Kirsch ILCC-20 Page 24

25. Viewing Angle Independent
Contrast (VIP)
• VIP (1980) is the basis for most modern TN LCDs
⎛π ⎞
sin 2 ⎜ 1+ u2 ⎟
T (u ) =
1 ⎝2 ⎠
2 1+ u 2
C. H. Gooch, H. A. Tarry, J. Phys. D: Appl. Phys. 1975, 8, 1575-1584
Dr. Peer Kirsch ILCC-20 Page 25

26. The Super Twisted Nematic
(STN) Mode
• T. J. Scheffer, J. Nehring
(BBC), 1981
• Extension of the limit for
multiplexing large pixel
arrays: the first high
resolution LCDs
picture: T. Uchida, Ekisho 1999, 3, 195-204
Dr. Peer Kirsch ILCC-20 Page 26

27. Alkenyls
• Merck purchased in 1996 the NLC portfolio from
Hoffmann-La Roche
• Advantages:
– Increased tendency to form nematic phases
– Advantageous elastic constants: large K33/K11
– Often low rotational viscosities (γ1)
F
H H
CH3 F
H H
CCP-V2-1: C 54 SB 104 N 176.6 I CCG-V-F: C 74 N 108.9 I
∆εvirt = 4.3
H
C5H11 CC-5-V: C -9 SB 52 N 62.6 I
H
Dr. Peer Kirsch ILCC-20 Page 27

28. Chiral Dopants
• Used in low concentration for inducing uniform pitch in TN
and STN mixtures
F
O C6H13
H13C6O O * H11C5 O
O C5H11 * CH
CH3 6 13
14 µm-1 a
O
O
9.1 µm-1 c F CH3
F
O * O H
O H7C3 O
H * CH
6 13
F CH3
H11C5 13.6 µm-1 a
39.5 µm-1 b
• Newest generation for SSCT mode (2000)
O a MLC-6012
C3H7
O b ZLI-1132
c MLC-6260
104 µm-1 c
Dr. Peer Kirsch ILCC-20 Page 28

29. Active Matrix Addressing
• Proposed already for the
DSM mode by B. J. Lechner
in 1971
• First prototypes presented by
Sharp in 1987
• Technical basis for all high-
resolution full colour LCDs
picture left: Scientific American 1997 (11), 87
Dr. Peer Kirsch ILCC-20 Page 29

30. Super Fluorinated Materials (SFM)
• 1989: Trifluorophenyl Derivatives
F F
H
H7C3 F H7C3 F
H
F F
• 1990: Trifluoromethoxyphenyl Derivatives
H
H7C3 OCF3
H
• 1990: Difluoromethoxyphenyl Derivatives
F
H
H7C3 OCHF2
H
F
Dr. Peer Kirsch ILCC-20 Page 30

31. Extension of the SFM Concept
• Additional lateral fluorine substituents on neighbouring
rings: F F
H
H7C3 F H7C3 F
H
F F F F
F
H7C3 F
F F
• Polar rings and linking groups:
F F
H O
H7C3 F H O F
H O H7C3
F H O F
Dr. Peer Kirsch ILCC-20 Page 31

32. Why Fluorinated Liquid Crystals?
F F F
F F
Improved mesophase range
by fluorinated bridges 2000 H7C3
F
F
O F
TNI,virt = 128 C
F
H7C3 CF3 +
Good voltage holding ratio,
high specific resistivity 1990
H7C3 N +
H7C3 CF3 ∆ε ~ 9
High dielectric anisotropy (∆ε) 1985
due to polarized C-F bond H7C3 CN ∆ε ~ 21
F
H9C4
Broader nematic phase range, 1980 C4H9
C 34 N 177.7 I
lower melting point F
H7C3 C2H5
C 171 S? (160) N 216.8 I

33. Property Prediction by Molecular
Modelling
Predictable:
• Dielectric anisotropy (∆ε)
• Birefringence (∆n)
• "Reliability" parameters (qualitative)
Not (yet) predictable:
• Mesophase sequence, clearing
point (TNI)
• Viscoelastic properties (γ1, Kxy)
M. Bremer, K. Tarumi, Adv. Mater. 1993, 5, 842-848.
M. Klasen, M. Bremer, A. Götz, A. Manabe, S. Naemura, K. Tarumi, Jpn. J. Appl. Phys. 1998, 37, L945-L948.
Dr. Peer Kirsch ILCC-20 Page 33

34. Combinatorial Chemistry and
Automated Parallel Synthesis
Dr. Peer Kirsch ILCC-20 Page 34

35. In Plane Switching (IPS) Mode
• Patent of the Fraunhofer Institute of
Applied Solid State Physics, Freiburg,
1990
• Acquired by Merck in 1994
• Co-development together with Hitachi
Ltd.
• Advantages:
– Dramatically improved viewing angle
of up to 170°
– High contrast ratio
• Requires materials with strongly
positive ∆ε
Dr. Peer Kirsch ILCC-20 Page 35

36. Low Birefringent Materials - 1
• Problem: most bicyclohexyl based liquid crystals tend to
have only smectic phases or poor solubility
• 1998: Trifluoromethyl bicyclohexyls have found wide
spread use in reflective and transflective LCDs
H
CF3
H
C 19 SH? (8) SB? 41 I
∆εvirt = 6.8 ∆nvirt = 0.059
Dr. Peer Kirsch ILCC-20 Page 36

37. Low Birefringent Materials - 2
• Alternative approach: Materials with negative
birefringence as internal ∆n compensators in LC mixtures
• 2001: Bicyclohexyl "dimers" with triacetylene as
perpendicular polarizable bridging group
H11C5 C5H11
C 90 N (63) I
∆nvirt = -0.012
∆n = -0.0104 (T/TNI = 0.95)
H11C5 C5H11
V. Reiffenrath, M. Bremer (Merck), 2001
Dr. Peer Kirsch ILCC-20 Page 37

38. Difluoroethers: The CF2O Bridge
• Substance class first characterized by E. Bartmann and K.
Tarumi (Merck), 1995
• Technical synthesis developed by P. Kirsch, A. Taugerbeck,
M. Bremer and D. Pauluth (Merck), 2000
F F
H O F O F
R R
H F F
F F F F
F
F
O F
R
F
F F
F
Dr. Peer Kirsch ILCC-20 Page 38

39. Difluoroethers: Properties
• Comparison with directly linked materials:
– Increased nematic phase range: TNI increased by 10-15 K, melting
points decreased
– ∆ε increased, ∆n decreased
– Reduction of γ1 by 10-15%
– Improved solubility
F
F
H
H O F
H7C3 F
H7C3
H F
H F F
F
C 66 N 94.1 I C 44 N 105.3 I
∆εvirt = 9.7 ∆εvirt = 10.5
∆nvirt = 0.073 ∆nvirt = 0.067
γ1,virt = 171 mPa·s γ1,virt = 145 mPa·s
Dr. Peer Kirsch ILCC-20 Page 39

40. Other Difluoroether Materials
• High stability and enhancement of solubility makes use of
"unusual" structural elements possible
H3C
H3C H
H H
F O
H O SF5
F F H R
F H F
F
F
F F F
F F
H7C3 O F
F
F
F
Dr. Peer Kirsch ILCC-20 Page 40

41. Tetrahydropyranes
• Tetrahydropyrane derivatives as highly polar SFM
materials with improved stability
F
C 35 N 66.3 I
H O F ∆εvirt = 14.0 ∆nvirt = 0.065
H7C3 γ1,virt = 158 mPa·s
O H F
F F
F
F F C 83 N (83.0) I
O F ∆εvirt = 35.6 ∆nvirt = 0.132
H7C3 γ1,virt = 457 mPa·s
O F
F F
F F
P. Kirsch, E. Poetsch (Merck), 2001
Dr. Peer Kirsch ILCC-20 Page 41

42. Vertical Alignment (VA) Mode
• MVA monitors by Fujitsu since 1996
• ASV TV by Sharp since 2002
• Advantages:
– Viewing angle of up to 170°
– High contrast ratio
– Fast response times
• Requires materials with negative ∆ε
pictures: MVA (Fujitsu),
ASV (Sharp)
Dr. Peer Kirsch ILCC-20 Page 42

43. German Future Prize 2003
M. Bremer, M. Klasen-Memmer, K. Tarumi, Nov 13, 2003
Dr. Peer Kirsch ILCC-20 Page 43

44. 2,3-Difluorophenylene Derivatives
• 1989: First SFM materials with strongly negative ∆ε
developed within FLC project (sold in 1995 to Hoechst)
H O
N R
H O OEt
R R
N N
H
R OEt R OEt
H
F F F F
R OEt
F F
Dr. Peer Kirsch ILCC-20 Page 44

45. Difluoroindanes
• Fluorinated indanes are the first fundamentally new type
of materials with negative ∆ε since the 2,3-
difluorophenylene derivatives: M. Bremer, L. Lietzau
(Merck), 2001
H
H7C3 H7C3
F H F
F F F F
F F
C 85 I C 130 SB 168 N 203.7 I
∆εvirt = -8.6 ∆εvirt = -8.4
Dr. Peer Kirsch ILCC-20 Page 45

46. The Past
2004: New LC production plant in Darmstadt
2002: Merck Ltd., Hong Kong
1997: Together with Fujitsu co-development of VA mode
Merck Display Technologies Ltd., Taiwan
1996: Purchase of NLC patent portfolio from Hoffmann-La Roche
Application laboratory in Taiwan
1995: Together with Hitachi co-development of IPS mode
Sales of FLC patent portfolio to Hoechst
1993: Joint venture with Balzers on ITO glass
1989: Application laboratory in Seoul, Korea
1985: Purchase of BBC patent portfolio
1980: Application laboratory in Atsugi, Japan
1968: Start of active LC research at Darmstadt
Dr. Peer Kirsch ILCC-20 Page 46

47. The Present:
The Liquid Crystals Division
• Employees woldwide: 400 people, including 150 people
in R&D
• Production volume: 60 tons of liquid crystals in 2002
• Sales 2003: over 400 Mio EUR
Dr. Peer Kirsch ILCC-20 Page 47

48. The Future -1:
Transition from CRT to LCD
Source – iSuppli/Stanford Resources
250.000
225.000
200.000
Thousands of Units
175.000
150.000
125.000
100.000
75.000
50.000
25.000
0
2002 2003 2004 2005 2006 2007
CRT (TV + Monitor)
LCD (TV + Monitor)
Dr. Peer Kirsch ILCC-20 Page 48

49. The Future - 2
• In 2004 completion
of a new liquid
crystal production
facility at Merck,
Darmstadt
• Investment: 250
MioEUR
• Capacity: 150 tons
per year
Dr. Peer Kirsch ILCC-20 Page 49

50. Acknowledgements
Chemistry Physics
Dr. M. Bremer Dr. M. Heckmeier
Dr. J. Krause Dr. M. Klasen-Memmer
Dr. L. Lietzau Dr. G. Lüssem
Dr. E. Montenegro A. Manabe
Dr. D. Pauluth Dr. K. Tarumi
Dr. E. Poetsch
V. Reiffenrath
Dr. A. Taugerbeck
Dr. W. Becker and Dr. S. Bernschneider-Reif is thanked for historical data
and market forecasts
Financial Support (€ & ¥)
Ministry of International Trade and Industry (MITI)
Bundesministerium für Bildung und Forschung (01 B 621/1, 01 BM 904)
Dr. Peer Kirsch ILCC-20 Page 50

51. The LC R&D Team at Darmstadt
Dr. Peer Kirsch ILCC-20 Page 51