Liquid crystal display device with residual retardation compensated for in liquid crystal layer

A liquid crystal display device, comprising:

• (a) a pair of substrates having electrodes;
• (b) a liquid crystal layer having a Spiral structure, arranged between said substrates;
• (c) a pair of polarizers arranged so as to sandwich said liquid crystal layer;
• (d) a birefringent medium arranged between said liquid crystal layer and one of said polarizers;
• and
• (e) structure for applying voltage to said electrodes,
• wherein retardation in said birefringent medium is set to be substantially equal to residual retardation due to the liquid crystal molecules at boundary regions upon application of the voltage to the liquid crystal layer.

In a liquid crystal display device comprising

• (a) a pair of substrates each having an electrode;
• (b) a liquid crystal layer arranged between said substrates;
• (c) a pair of polarizers;
• and
• (d) control structure for changing transmission of said liquid crystal layer by applying voltages of two or more values between said electrodes,
• wherein each of said polarizers includes a polarizing film and birefringent transparent protective films sandwiching said polarizing film, and the total retardation in all of said protective films is in a range of 0.005-0.25 .mu.m.

A liquid crystal display device, comprising:

• (a) a pair of substrates each having an electrode arranged oppositely to each other, at least one of them being transparent;
• (b) a liquid crystal layer having a spiral structure, arranged between said substrates;
• (c) a pair of polarizers arranged so as to sandwich said liquid crystal layer;
• (d) a birefringent medium arranged between said liquid crystal layer and at least one of said polarizers, retardation in said birefringent medium being equal or close to residual retardation due to the liquid crystal molecules at boundary regions, the retardation in the birefringent medium being 0.01-0.15 .mu.m, and the slow axis of said birefringent medium being set for an angle to compensate for said residual retardation;
• and
• (e) control structure for changing transmission of said liquid crystal layer by applying voltages of two or more values between said electrodes.

A liquid crystal display device comprising:

• (a) a pair of substrates each having an electrode arranged oppositely to each other, at least one of them being transparent;
• (b) a liquid crystal layer arranged between said substrates, the liquid crystal layer having a spiral structure;
• (c) a pair of polarizers arranged so as to sandwich said liquid crystal layer;
• (d) a birefringent medium arranged between said liquid crystal layer and at least one of said polarizers, retardation in said birefringent medium being equal or close to residual retardation due to the liquid crystal molecules at boundary regions, and the slow axis of said birefringent medium being set for an angle to compensate for said residual retardation and wherein said liquid crystal layer has a twist angle of 10-80.degree. and refractive index anisotropy .DELTA.n of 0.02-0.2, a product .DELTA.n.multidot.d of the thickness (.mu.m) of said liquid crystal layer and said refractive index anisotropy is 0.2-0.7 .mu.m, retardation in said birefringent medium is 0.005-0.2 .mu.m, and the slow axis of said birefringent medium crosses a rubbing axis of at least one of said boundary regions;
• and
• (e) control structure for changing transmission of said liquid crystal layer by applying voltages of two or more values between said electrodes.

A liquid crystal display device comprising:

• (a) a pair of substrates each having an electrode arranged oppositely to each other, at least one of them being transparent;
• (b) a liquid crystal layer having a spiral structure, arranged between said substrates;
• (c) a pair of polarizers arranged so as to sandwich said liquid crystal layer;
• (d) a birefringent medium arranged between said liquid crystal layer and at least one of said polarizers, retardation in said birefringent medium being equal or close to residual retardation due to the liquid crystal molecules at boundary regions, and the slow axis of said birefringent medium being set for an angle to compensate for said residual retardation, said birefringent medium including a transparent polymer film whose slow axis crosses rubbing axes of said boundary regions, said slow axis of said polymer film being orthogonal to a vector sum in rubbing directions of said boundary regions;
• and
• (e) control structure for changing transmission of said liquid crystal layer by applying voltages of two or more values between said electrodes.

A liquid crystal display device comprising:

• (a) a pair of substrates each having an electrode arranged oppositely to each other, at least one of them being transparent;
• (b) a liquid crystal layer arranged between said substrates;
• (c) a pair of polarizers arranged so as to sandwich said liquid crystal layer;
• (d) a birefringent medium arranged between said liquid crystal layer and at least one of said polarizers, retardation in said birefringent medium being equal or close to residual retardation due to the liquid crystal molecules at boundary regions, and the slow axis of said birefringent medium being set for an angle to compensate for said residual retardation, said birefringent medium including two transparent organic polymer films whose slow axes cross each other, retardation in the organic polymer films being different, and wherein a difference in the retardation between adjacent stacked films is smaller than that in each individual film;
• and
• (e) control structure for changing transmission of said liquid crystal layer by applying voltages of two or more values between said electrodes.

A liquid crystal display device, comprising:

• (a) a pair of substrates each having an electrode arranged oppositely to each other, at least one of them being transparent;
• (b) a liquid crystal layer arranged between said substrates;
• (c) a pair of polarizers arranged so as to sandwich -said liquid crystal layer;
• (d) a birefringent medium arranged between said liquid crystal layer and at least one of said polarizers, retardation in said birefringent medium being equal or close to residual retardation due to the liquid crystal molecules at boundary regions, and the slow axis of said birefringent medium being set for an angle to compensate for said residual retardation, said birefringent medium including two transparent organic polymer films whose slow axes cross each other, and wherein each of said organic polymer films has a positive dispersion characteristic in which wavelength dispersion in birefringent retardation is different from the absolute value of retardation at a wavelength of 0.55 .mu.m;
• and
• (e) control structure for changing transmission of said liquid crystal layer by applying voltages of two or more values between said electrodes.

A liquid crystal display device comprising:

• (a) a pair of substrates each having an electrode arranged oppositely to each other, at least one of them being transparent;
• (b) a liquid crystal layer arranged between said substrates, said liquid crystal layer having a spiral structure;
• (c) a pair of polarizers arranged so as to sandwich said liquid crystal layer;
• (d) a birefringent medium arranged between said liquid crystal layer and at least one of said polarizers, said birefringent medium having a retardation and a slow axis, the retardation in said birefringent medium being equal or close to a residual retardation due to the liquid crystal molecules at boundary regions, and the slow axis of said birefringent medium being set for an angle to compensate for said residual retardation;
• and
• (e) control structure for changing transmission of said liquid crystal layer by applying voltages of two or more values between said electrodes.

A liquid crystal display device comprising:

• (a) a pair of substrates each having an electrode arranged oppositely to each other, at least one of them being transparent;
• (b) a liquid crystal layer arranged between said substrates;
• (c) a pair of polarizers arranged so as to sandwich said liquid crystal layer;
• (d) a birefringent medium arranged between said pair of substrates, said birefringent medium having a retardation and a slow axis, the retardation in said birefringent medium being equal or close to a residual retardation due to the liquid crystal molecules at boundary regions, and the slow axis of said birefringent medium being set for an angle to compensate for said residual retardation;
• and
• (e) control structure for changing transmission of said liquid crystal layer by applying voltages of two or more values between said electrodes.

A liquid crystal display device comprising:

• (a) a pair of substrates each having an electrode arranged oppositely to each other, at least one of them being transparent;
• (b) a liquid crystal layer arranged between said substrates;
• (c) a pair of polarizers arranged so as to sandwich said liquid crystal layer;
• (d) a birefringent medium arranged between said liquid crystal layer and at least one of said polarizers, said birefringent medium having a retardation and a slow axis, the retardation in said birefringent medium being equal or close to a residual retardation due to the liquid crystal molecules at boundary regions, and the slow axis of said birefringent medium being set for an angle to compensate for said residual retardation, the birefringent medium including at least two different kinds of polymer films, with wavelength dispersion characteristics of refractive indices of the liquid crystal layer and the polymer films being substantially equal;
• and
• (e) control structure for changing transmission of said liquid crystal layer by applying voltages of two or more values between said electrodes.