Liquid crystal eyewear with two identical guest host subcells and tilted homeotropic alignment

A liquid crystal cell for use in light responsive, transmissivity variable eyewear which is exposed to unpolarized light, said cell comprising:

• (a) first subcell means including a liquid crystal mixture for acting on said unpolarized light as the latter passes through said liquid crystal mixture in a way which causes light of a first polarization making up said unpolarized light to be attenuated as a function of a particular variable;
• and
• (b) second subcell means including a liquid crystal mixture positioned immediately adjacent the first subcell means for acting on said unpolarized light passing through the liquid crystal mixture in a way which attenuates light of the second polarization of the polarized light in accordance with that variable, whereby all of the light of said unpolarized light is attenuated as a function of said variable,
• said first and second subcells being substantially identical but oriented differently with respect to one another so as to attenuate both of said polarizations of said unpolarized light,
• wherein each of said subcells includes a separate and distinct outer substrate and a common intermediate substrate in confronting parallel relationship to one another so as to include outer confronting surfaces and inner confronting surfaces, the latter being substantially uniformly spaced from one another along the entire extent of the substrates;
• wherein a pair of transparent electrodes are respectively disposed over the inner surfaces of said outer substrates and connectable to a voltage control arrangement in which under one condition an electric field is applied across both subcells in a direction normal said inner surfaces and under a second condition no electric field is applied across said substrates;
• wherein a guest-host liquid crystal/dye mixture is contained between each outer substrate and the adjacent intermediate common substrate, said mixture including
• liquid crystal molecules having negative dielectric anisotropy and defining long axes and
• dichroic dye molecules which also define long axes and which preferentially absorb light that is polarized along their long axes;
• and
• wherein tilted homeotropic alignment means are disposed on the inner confronting surface of each of said outer substrates for acting on said guest-host liquid crystal/dye mixture (i) such that, in the absence of an electric field across said substrates, the long axes of said liquid crystal and dye molecules line up relative to said substrates in a way which causes the dye molecules not to absorb substantially any light that is directed through the guest-host liquid crystal/dye mixture normal to the substrates whether the light passing therethrough is polarized or not, whereby the liquid crystal cell is substantially clear in the absence of said electric field and (ii) such that, in the presence of said electric field across said substrates, the long axes of said liquid crystal and dye molecules line up relative to said substrates in a way which causes the dye molecules to absorb at least some light that is directed through the guest-host liquid crystal/dye mixture normal to the substrates so long as the last-mentioned light is polarize along the long axes of the dye molecules, whereby the liquid crystal cell darkens in the presence of said electric field.

Light responsive, transmissivity variable eyewear, comprising:

• (a) a frame;
• (b) a voltage control arrangement operable between a first voltage condition and a second voltage condition;
• and
• (c) at least one liquid crystal cell supported by said frame, said cell including
• (i) first subcell means including a liquid crystal mixture for acting on unpolarized light as the latter passes through said liquid crystal mixture in a way which causes light of a first polarization making up said unpolarized light to be attenuated as a function of a particular variable,
• (ii) second subcell means including a liquid crystal mixture positioned immediately adjacent the first subcell means for acting on said unpolarized light passing through the liquid crystal mixture in a way which attenuates light of the second polarization of the polarized light in accordance with that variable, whereby all of the light of said unpolarized light is attenuated as a function of said variable,
• said first and second subcells means including first and second outer substrates and a common inner substrate, said voltage control means including means for applying individual voltages across said first outer substrate and common substrate and said second outer substrate and said common substrate respectively.