Patent ID: 12227688

EXAMPLES

The following examples explain the present invention without restricting it. However, they show the person skilled in the art preferred mixture concepts with compounds preferably to be employed and the respective concentrations thereof and combinations thereof with one another. In addition, the examples illustrate which properties and property combinations are accessible.

In addition, the following abbreviations and symbols are used:V0threshold voltage, capacitive [V] at 20° C.,neextraordinary refractive index at 20° C. and 589 nm,n0ordinary refractive index at 20° C. and 589 nm,Δn optical anisotropy at 20° C. and 589 nm,ε⊥dielectric permittivity perpendicular to the director at 20° C. and 1 kHz,ε∥dielectric permittivity parallel to the director at 20° C. and 1 kHz,Δε dielectric anisotropy at 20° C. and 1 kHz,cl.p., T(N,I) clearing point [° C.],γ1rotational viscosity at 20° C. [mPa·s],K1elastic constant, “splay” deformation at 20° C. [pN],K2elastic constant, “twist” deformation at 20° C. [pN],K3elastic constant, “bend” deformation at 20° C. [pN].

Unless explicitly noted otherwise, all concentrations in the present application are quoted in percent by weight and relate to the corresponding mixture as a whole, comprising all solid or liquid-crystalline components, without solvents.

Unless explicitly noted otherwise, all temperature values indicated in the present application, such as, for example, for the melting point T(C,N), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T(N,I), are quoted in degrees Celsius (° C.). M.p. denotes melting point, cl.p.=clearing point. Furthermore, C=crystalline state, N=nematic phase, S=smectic phase and I=isotropic phase. The data between these symbols represent the transition temperatures.

All physical properties are and have been determined in accordance with “Merck Liquid Crystals, Physical Properties of Liquid Crystals”, Status November 1997, Merck KGaA, Germany, and apply for a temperature of 20° C., and Δn is determined at 589 nm and Δε at 1 kHz, unless explicitly indicated otherwise in each case.

The term “threshold voltage” for the present invention relates to the capacitive threshold (V0), also known as the Freedericks threshold, unless explicitly indicated otherwise. In the examples, the optical threshold may also, as generally usual, be quoted for 10% relative contrast (V10).

Unless stated otherwise, the process of polymerizing the polymerizable compounds in the PSA displays as described above and below is carried out at a temperature where the LC medium exhibits a liquid crystal phase, preferably a nematic phase, and most preferably is carried out at room temperature.

Unless stated otherwise, methods of preparing test cells and measuring their electrooptical and other properties are carried out by the methods as described hereinafter or in analogy thereto.

The display used for measurement of the capacitive threshold voltage consists of two plane-parallel glass outer plates at a separation of 25 μm, each of which has on the inside an electrode layer and an unrubbed polyimide alignment layer on top, which effect a homeotropic edge alignment of the liquid-crystal molecules.

The PSVA display or PSVA test cell used for measurement of the tilt angles consists of two plane-parallel glass outer plates at a separation of ca. 3.3 μm unless stated otherwise, each of which has on the inside an electrode layer and a polyimide alignment layer on top, where the two polyimide layers are rubbed antiparallel to one another and effect a homeotropic edge alignment of the liquid-crystal molecules. The SAVA display or test cell have one or no polyimide orientation layer and a patterned electrode structure resulting in two or more domains of LC orientation direction. For tilt measurements, the light of a single domain is transmitted by the use of light blocking layers or shields.

The polymerizable compounds are polymerized in the display or test cell by irradiation with UV light of defined intensity for a prespecified time, with a voltage simultaneously being applied to the display (usually 10 V to 30 V alternating current, 1 kHz). In the examples, unless indicated otherwise, a metal halide lamp and an intensity of 100 mW/cm2is used for polymerization. The intensity is measured using a standard meter (Hoenle UV-meter high end with UV sensor).

The tilt angle is determined using the Mueller Matrix Polarimeter “AxoScan” from Axometrics. A low value (i.e. a large deviation from the 90° angle) corresponds to a large tilt here.

The tilt angle can be also determined by the polarimeter RETS from Otsuka Electronics Co., Ltd. For VA mode case, for small retardation values the tilt-angle is small, which means the LC director is close to the vertical (homeotropic) alignment.

Unless stated otherwise, the term “tilt angle” means the angle between the LC director and the substrate, and “LC director” means in a layer of LC molecules with uniform orientation the preferred orientation direction of the optical main axis of the LC molecules, which corresponds, in case of calamitic, uniaxially positive birefringent LC molecules, to their molecular long axis.

Example 1

The nematic LC host mixture N1 is formulated as follows

B-2O-O54.00%cl.p.74.2° C.BCH-328.00%Δn0.1091CC-3-V19.00%ne1.5953CCH-3012.00%no1.4862CCH-348.00%Δε−3.1CCH-357.00%ε||3.6CCP-3-18.00%ε⊥6.7CCP-V2-15.00%γ1108 mPa · sCCY-3-O210.50%K114.8CLY-3-O21.00%K316.5CPY-3-O22.50%K3/K11.14CY-3-O211.50%V02.41 VPCH-3015.50%PY-3-O218.00%

Polymerizable mixture P1 is prepared by mixing 0.35% of the polymerizable compound RM-1 with 99.65% of the mixture N1.

The dyed polymerizable mixture P1R is prepared by adding 0.2% of the red dye F-355 of formula I*1a1 to the polymerizable mixture P1.

The UV-vis spectrum of dyed polymerizable mixture P1R shows an absorption peak at ca. 550 nm. The dyed polymerizable mixture P1R is thus suitable to absorb undesired green light emitted by the QDCF into the LC layer.

The dyed polymerizable mixture P1B is prepared by adding 0.2% of the blue dye F-593 of formula I*4a1 to the polymerizable mixture P1.

The UV-vis spectrum of dyed polymerizable mixture P1B shows an absorption peak at ca. 630 nm. The dyed polymerizable mixture P1B is thus suitable to absorb undesired red light emitted by the QDCF into the LC layer.

Example 2

The nematic LC host mixture N2 is formulated as follows

B-(c5)1O-O24.00%cl.p.74.1° C.BCH-328.00%CC-3-V19.00%CCH-3012.00%CCH-348.00%CCH-357.00%CCP-3-18.00%CCP-V2-15.00%CCY-3-O210.50%CLY-3-O21.00%CPY-3-O22.50%CY-3-O211.50%PCH-3015.50%PY-3-O218.00%

Polymerizable mixture P2 is prepared by mixing 0.3% of the polymerizable compound RM-1 with 99.7% of the mixture N2.

Dyed polymerizable mixture P2R is prepared by adding 0.2% of the red dye F-355 of formula I*1a1 to the polymerizable mixture P2.

Dyed polymerizable mixture P2B is prepared by adding 0.2% of the blue dye F-593 of formula I*4a1 to the polymerizable mixture P2.

Example 3

The nematic LC host mixture N3 is formulated as follows

B-(c3)1O-O22.00%cl.p.74.1° C.B-2O-O52.00%BCH-328.00%CC-3-V19.00%CCH-3012.00%CCH-348.00%CCH-357.00%CCP-3-18.00%CCP-V2-15.00%CCY-3-O210.50%CLY-3-O21.00%CPY-3-O22.50%CY-3-O211.50%PCH-3015.50%PY-3-O218.00%

Polymerizable mixture P3 is prepared by mixing 0.3% of the polymerizable compound RM-35 with 99.7% of the mixture N3.

Dyed polymerizable mixture P3R is prepared by adding 0.2% of the red dye F-355 of formula I*1a1 to the polymerizable mixture P3.

Dyed polymerizable mixture P3B is prepared by adding 0.2% of the blue dye F-593 of formula I*4a1 to the polymerizable mixture P3.

Example 4

The nematic LC host mixture N4 is formulated as follows

B(S)-(c3)1O-O22.00%cl.p.74.1° C.B(S)-2O-O52.00%BCH-328.00%CC-3-V19.00%CCH-3012.00%CCH-348.00%CCH-357.00%CCP-3-18.00%CCP-V2-15.00%CCY-3-O210.50%CLY-3-O21.00%CPY-3-O22.50%CY-3-O211.50%PCH-3015.50%PY-3-O218.00%

Polymerizable mixture P4 is prepared by mixing 0.3% of the polymerizable compound RM-170 with 99.7% of the mixture N4.

Dyed polymerizable mixture P4R is prepared by adding 0.2% of the red dye F-355 of formula I*1a1 to the polymerizable mixture P4.

Dyed polymerizable mixture P4B is prepared by adding 0.2% of the blue dye F-593 of formula I*4a1 to the polymerizable mixture P4.

Example 5

The nematic LC host mixture N5 is formulated as follows

B(S)-2O-O54.00%cl.p.74.3° C.BCH-328.00%CC-3-V19.00%CCH-3012.00%CCH-348.00%CCH-357.00%CCP-3-18.00%CCP-V2-15.00%CCY-3-O210.50%CLY-3-O21.00%CPY-3-O22.50%CY-3-O211.50%PCH-3015.50%PY-3-O218.00%

Polymerizable mixture P5 is prepared by mixing 0.3% of the polymerizable compound RM-145 with 99.7% of the mixture N5.

Dyed polymerizable mixture P5R is prepared by adding 0.2% of the red dye F-355 of formula I*1a1 to the polymerizable mixture P5.

Dyed polymerizable mixture P5B is prepared by adding 0.2% of the blue dye F-593 of formula I*4a1 to the polymerizable mixture P5.

The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. From the description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.

The entire disclosures of all applications, patents and publications, cited herein and of corresponding EP application No. 21171926.5, filed May 4, 2021, are incorporated by reference herein.