Liquid crystal display device

Claim 2

A liquid crystal display device comprising: a pair of substrates having surfaces which oppose each other and on which electrodes and orientation films covering said electrodes and having undergone orientation processing in predetermined directions are formed; a nematic liquid crystal layer which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a predetermined range of angles from one substrate to the other; a pair of polarizing plates arranged outside said pair of substrates to sandwich said substrates; and at least one twist-aligned retardation plate which is arranged between said pair of polarizing plates and in which polymer molecules are oriented nearly perpendicular with respect to a surface of the plate and the arrangement of the polymer molecules is twist-aligned over a predetermined range of angles in a direction from one surface to the other.

Claim 3

A liquid crystal display device comprising: a pair of substrates having surfaces which oppose each other and on which electrodes and orientation films covering said electrodes and having undergone orientation processing in predetermined directions are formed; a nematic liquid crystal layer which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a range of angles from 80° to 120° in a direction from one substrate to the other; a pair of polarizing plates arranged outside said pair of substrates to sandwich said substrates; and two twist-aligned retardation plates which are arranged between said pair of polarizing plates and in which polymer molecules are arranged substantially parallel to each surface and the arrangement of the polymer molecules is twist-aligned in a predetermined range of angles in a direction from one surface to the other, each of said two twist-aligned retardation plates having a refractive index anisotropy Δn and a plate thickness d, a product Δn.d of which is positive, the polymer molecules of one of said two twist-aligned retardation plates being twist-aligned 80° to 120° in the same direction as the twist direction of the nematic liquid crystal layer, and the polymer molecules of the other twist aligned retardation plate being twist-aligned 80° to 120° in a direction opposite to the twist direction of the nematic liquid crystal layer.

Claim 4

A liquid crystal display device comprising: a pair of substrates having surfaces which oppose each other and on which electrodes and orientation films covering said electrodes and having undergone orientation processing in predetermined directions are formed; a nematic liquid crystal layer which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a range of angles from 80° to 120° in a direction from one substrate to the other; a pair of polarizing plates arranged outside said pair of substrates to sandwich said substrates; and two twist-aligned retardation plates which are arranged between said pair of polarizing plates and in which polymer molecules are arranged substantially parallel to each surface and the arrangement of the polymer molecules is twist-aligned in a predetermined range of angles in a direction from one surface to the other, each of said two twist-aligned retardation plates having a refractive index anisotropy Δn and a plate thickness d, a product Δn.d of which is positive, the polymer molecules of one of said two twist-aligned retardation plates being twist-aligned 80° to 120° in the same direction as the twist direction of the nematic liquid crystal layer, and the polymer molecules of the other twist aligned retardation plate being twist-aligned 80° to 120° in a direction opposite to the twist direction of the nematic liquid crystal layer.

Claim 5

A liquid crystal display device according to claim 2, wherein said two twist-aligned retardation plates are arranged between one of the polarizing plates and that of the substrates which opposes said one of the polarizing plates.

Claim 6

A liquid crystal display device according to claim 2, wherein one of said two twist-aligned retardation plates is arranged between one of the polarizing plates and the substrate which opposes said one of the polarizing plates, and the other of said two twist-aligned retardation plates is arranged between the other one of the polarizing plates and the other of the substrates which opposes said other one of the polarizing plates.

Claim 7

A liquid crystal display device comprising: a pair of substrates having surfaces which oppose each other and on which electrodes and orientation films covering said electrodes and having undergone orientation processing in predetermined directions are formed; a nematic liquid crystal layer which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a predetermined range of angles in a direction from one substrate to the other; a pair of polarizing plates arranged outside said pair of substrates to sandwich said substrates; and at least two twist-aligned retardation plates which are arranged between said pair of polarizing plates and in which polymer molecules are arranged so as to be twist-aligned in a predetermined range of angles in a direction from one surface to the other, each of said twist-aligned retardation plates having a refractive index anisotropy Δn and a plate thickness d, a product Δn.d of which is positive.

Claim 8

A liquid crystal display device comprising: a pair of substrates having surfaces which oppose each other and on which electrodes and orientation films covering said electrodes and having undergone orientation processing in predetermined directions are formed; a nematic liquid crystal layer which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a predetermined range of angles in a direction from one substrate to the other; a pair of polarizing plates arranged outside said pair of substrates to sandwich said substrates; and at least two twist-aligned retardation plates which are arranged between said pair of polarizing plates and in which polymer molecules are arranged so as to be twist-aligned in a predetermined range of angles in a direction from one surface to the other, each of said twist-aligned retardation plates having a refractive index anisotropy Δn and a plate thickness d, a product Δn.d of which is positive.

Claim 9

A liquid crystal display device according to claim 5, wherein there are only two said twist-aligned retardation plates.

Claim 10

A liquid crystal display device according to claim 6, wherein said two twist-aligned retardation plates are arranged between one of the polarizing plates and the substrate which opposes said one of the polarizing plates.

Claim 11

A liquid crystal display device according to claim 6, wherein one of said two twist-aligned retardation plates is arranged between one of the polarizing plates and the substrate which opposes said one of the polarizing plates, and the other of said two twist-aligned retardation plates is arranged between the other one of the polarizing plates and the substrate which opposes said other one of the polarizing plates.

Claim 12

A liquid crystal display device according to claim 6, wherein the polymer molecules of one of said two twist-aligned retardation plates are twist-aligned 80° to 120° in the same direction as the twist direction of the nematic liquid crystal layer, and the polymer molecules of the other twist-aligned retardation plate are twist-aligned 80° to 120° in a direction opposite to the twist direction of the nematic liquid crystal layer.

Claim 13

A liquid crystal display device comprising: a pair of substrates having surfaces which oppose each other and on which electrodes and orientation films covering said electrodes and having undergone orientation processing in predetermined directions are formed; a nematic liquid crystal layer which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a range of angles from 80° to 120° in a direction from one substrate to the other; a pair of polarizing plates arranged outside said pair of substrates to sandwich said substrates; at least one twist-aligned retardation plate which is arranged between said pair of polarizing plates and in which polymer molecules are twist-aligned a plurality of times in a direction from one surface to the other in which the twist pitch is set to be smaller than 1/5 the wavelength at the lower limit of a visible light band; and said twist-aligned retardation plate having an effective refractive index anisotropy ΔN expressed by ##EQU3## assuming that n o is a refractive index with respect to ordinary rays and n e is a refractive index with respect to extraordinary rays and a plate thickness d, and wherein a product ΔN.d between ΔN and d is negative.

Claim 14

A liquid crystal display device comprising: a pair of substrates having surfaces which oppose each other and on which electrodes and orientation films covering said electrodes and having undergone orientation processing in predetermined directions are formed; a nematic liquid crystal layer which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a range of angles from 80° to 120° in a direction from one substrate to the other; a pair of polarizing plates arranged outside said pair of substrates to sandwich said substrates; at least one twist-aligned retardation plate which is arranged between said pair of polarizing plates and in which polymer molecules are twist-aligned a plurality of times in a direction from one surface to the other in which the twist pitch is set to be smaller than 1/5 the wavelength at the lower limit of a visible light band; and said twist-aligned retardation plate having an effective refractive index anisotropy ΔN expressed by ##EQU3## assuming that n o is a refractive index with respect to ordinary rays and n e is a refractive index with respect to extraordinary rays and a plate thickness d, and wherein a product ΔN.d between ΔN and d is negative.

Claim 15

A liquid crystal display device according to claim 10, wherein said product ΔN.d is in the range of -30 to -600 nm, and said polymer molecules are twist-aligned at least five times.

Claim 16

A liquid crystal display device comprising: a pair of substrates having surfaces which oppose each other and on which electrodes and orientation films covering said electrodes and having undergone orientation processing in predetermined directions are formed; nematic liquid crystal layer which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a range of angles from 80° to 120° in a direction from one substrate to the other; a pair of polarizing plates arranged outside said pair of substrates to sandwich said substrates; and two twist-aligned retardation plates which consist of an organic polymer film sandwiched between protective films and which are arranged between said pair of polarizing plates and in which polymer molecules are arranged substantially parallel to each surface, and the arrangement of the polymer molecules in one of said two twist-aligned retardation plates is twist-aligned in a range of angles from 80° to 120° in the same direction as the twist direction of the nematic liquid crystal layer, and the arrangement of the polymer molecules of the other twist-aligned retardation plate is twist-aligned in a range of angles from 80° to 120° in a direction opposite to the twist direction of the nematic liquid crystal layer.

Claim 17

A liquid crystal display device comprising: a pair of substrates having surfaces which oppose each other and on which electrodes and orientation films covering said electrodes and having undergone orientation processing in predetermined directions are formed; nematic liquid crystal layer which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a range of angles from 80° to 120° in a direction from one substrate to the other; a pair of polarizing plates arranged outside said pair of substrates to sandwich said substrates; and two twist-aligned retardation plates which consist of an organic polymer film sandwiched between protective films and which are arranged between said pair of polarizing plates and in which polymer molecules are arranged substantially parallel to each surface, and the arrangement of the polymer molecules in one of said two twist-aligned retardation plates is twist-aligned in a range of angles from 80° to 120° in the same direction as the twist direction of the nematic liquid crystal layer, and the arrangement of the polymer molecules of the other twist-aligned retardation plate is twist-aligned in a range of angles from 80° to 120° in a direction opposite to the twist direction of the nematic liquid crystal layer.

Claim 18

A liquid crystal display device according to claim 12, wherein said two twist-aligned retardation plates are arranged between one of said pair of polarizing plates and one of said pair of substrates which opposes said one polarizing plate.

Claim 19

A liquid crystal display device according to claim 12, wherein one of said two twist-aligned retardation plates is arranged between one of said polarizing plates and one of said substrates which opposes said one polarizing plate, and the other twist-aligned retardation plates is arranged between the other polarizing plate and the other substrate which opposes the other polarizing plate.

Claim 20

A liquid crystal display device comprising: a pair of substrates having surfaces which oppose each other and on which electrodes and orientation films covering said electrodes and having undergone orientation processing in predetermined directions are formed; a nematic liquid crystal layer which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a range of angles from 80° to 120° in a direction from one substrate to the other, said nematic liquid crystal layer having a refractive index anisotropy Δn c and a layer thickness d c , a product Δn c .d c of which is 300 to 600 nm; a pair of polarizing plates arranged outside said pair of substrates to sandwich said substrates; and two twist-aligned retardation plates for improving viewing angle characteristics, each said retardation plate consisting of an organic polymer film sandwiched between protective films and which are arranged between said pair of polarizing plates and in which polymer molecules are arranged substantially parallel to each surface, and the arrangement of the polymer molecules in one of said two twist-aligned retardation plates is twist-aligned in a range of angles from 80° to 120° in the same direction as the twist direction of the nematic liquid crystal layer, and the arrangement of the polymer molecules of the other twist-aligned retardation plate is twist-aligned in a range of angles from 80° to 120° in a direction opposite to the twist direction of the nematic liquid crystal layer, said retardation plate having a refractive index anisotropy Δn and a plate thickness d, a product Δn.d of which is 50 to 600 nm.

Claim 21

A liquid crystal display device comprising: a pair of substrates having surfaces which oppose each other and on which electrodes and orientation films covering said electrodes and having undergone orientation processing in predetermined directions are formed; a nematic liquid crystal layer which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a range of angles from 80° to 120° in a direction from one substrate to the other, said nematic liquid crystal layer having a refractive index anisotropy Δn c and a layer thickness d c , a product Δn c .d c of which is 300 to 600 nm; a pair of polarizing plates arranged outside said pair of substrates to sandwich said substrates; and two twist-aligned retardation plates for improving viewing angle characteristics, each said retardation plate consisting of an organic polymer film sandwiched between protective films and which are arranged between said pair of polarizing plates and in which polymer molecules are arranged substantially parallel to each surface, and the arrangement of the polymer molecules in one of said two twist-aligned retardation plates is twist-aligned in a range of angles from 80° to 120° in the same direction as the twist direction of the nematic liquid crystal layer, and the arrangement of the polymer molecules of the other twist-aligned retardation plate is twist-aligned in a range of angles from 80° to 120° in a direction opposite to the twist direction of the nematic liquid crystal layer, said retardation plate having a refractive index anisotropy Δn and a plate thickness d, a product Δn.d of which is 50 to 600 nm.

Claim 22

A liquid crystal display device according to claim 15, wherein a product Δn.d of a refractive index anisotropy Δn and a plate thickness d of said twist-aligned retardation plate is positive, and the arrangement of the molecules of said twist-aligned retardation plate is twist-aligned in a direction opposite to the twist direction of the twist arrangement of said nematic liquid crystal layer at the same twist angle.

Claim 23

A liquid crystal display device according to claim 15, wherein said two twist-aligned retardation plates are arranged between one of said pair of polarizing plates and one of said pair of substrates which opposes said one polarizing plate.

Claim 24

A liquid crystal display device according to claim 15, wherein one of said two twist-aligned retardation plates is arranged between one of said polarizing plates and one of said substrates which opposes said one polarizing plate, and the other twist-aligned retardation plate is arranged between the other polarizing plate and the other substrate which opposes the other polarizing plate.