Electro-optical devices using liquid crystals having a twist in a plane perpendicular to substrates

An electro-optical method using liquid crystals comprising the steps of:

• filling a space between two parallel transparent plates with a material which comprises molecules having nematic properties, the structure of the molecule initially defining a substantially rectilinear nematic director perpendicular to the plates;
• conferring on said material a structure defining a second nematic director curved at least once in a plane perpendicular to the plates by application of a magnetic field to the material, such that the second nematic director arrives substantially perpendicularly at at least one of the two plates;
• imparting a twist to the second nematic director along a component at right angles to said plane perpendicular to the plates;
• and
• causing light arriving with an incidence substantially at right angles to one of the plates to pass through the material, a rotation of polarization of the light, at an outlet from the plates, depending on the twist imparted to the second nematic director.

An electro-optical method using liquid crystals comprising the steps of:

• filling a space between two parallel transparent plates with a material which comprises molecules having nematic properties and non-vanishing flexoelectric anisotropy;
• conferring on said material a structure defining a nematic director curved at least once in a plane perpendicular to the plates such that the nematic director arrives substantially perpendicularly at at least one of the two plates;
• imparting a twist to the nematic director along a component at right angles to said plane perpendicular to the plates with application to the material of a low frequency electrical field having a component at right angles to said plane perpendicular to the plates;
• and
• causing light arriving with an incidence substantially at right angles to one of the plates to pass through the material, a rotation of polarization of the light, at an outlet from the plates, depending on the twist imparted to the nematic director.

An electro-optical method using liquid crystals comprising the steps of:

• filling a space between two parallel transparent plates with a material which comprises molecules having nematic properties and non-vanishing flexoelectric anisotropy;
• conferring on said material a structure defining a nematic director curved at least once in a plane perpendicular to the plates such that the nematic director arrives substantially perpendicularly at at least one of the two plates;
• imparting a twist to the nematic director along a component at right angles to said plane perpendicular to the plates with application to the material of a continuous electrical field having a component at right angles to said plane perpendicular to the plates;
• and
• causing light arriving with an incidence substantially at right angles to one of the plates to pass through the material, a rotation of polarization of the light, at an outlet from the plate, depending on the twist imparted to the nematic director.

An electro-optical method using liquid crystals comprising the steps of:

• filling a space between two parallel transparent plates with a material which comprises molecules having nematic properties;
• conferring on said material a structure defining a nematic director curved at least once in a plane perpendicular to the plates such that the nematic director arrives substantially perpendicularly at at least one of the two plates;
• imparting a twist to the nematic director along a component at right angles to said plane perpendicular to the plates with application to the material of a high frequency electrical field of orientation substantially parallel to the plates;
• and
• causing light arriving with an incidence substantially at right angles to one of the plates to pass through the material, a rotation of polarization of the light, at an outlet from the plate, depending on the twist imparted to the nematic director.

An electro-optical method using liquid crystals comprising the steps of:

• filling a space between two parallel transparent plates with a material which comprises molecules having nematic properties;
• conferring on said material a structure defining a nematic director curved at least once in a plane perpendicular to the plates such that the nematic director arrives substantially perpendicularly at at least one of the two plates;
• imparting a twist to the nematic director along a component at right angles to said plane perpendicular to the plates with application to the material of a magnetic field substantially parallel to the plates;
• and
• causing light arriving with an incidence substantially at right angles to one of the plates to pass through the material, a rotation of polarization of the light, at an outlet from the plates, depending on the twist imparted to the nematic director.

An electro-optical method using liquid crystals comprising the steps of:

• filling a space between two parallel transparent plates with a material which comprises molecules having nematic properties;
• conferring on said material a structure defining a nematic director curved at least once in a plane perpendicular to the plates such that the nematic director arrives substantially perpendicularly at at leat one of the two plates, and applying to the material a magnetic field which is oblique with respect to the plates in order to give preference to a particular area of the structure;
• imparting a twist to the nematic director along a component at right angles to said plane perpendicular to the plates;
• and
• causing light arriving with an incidence substantially at right angles to one of the plates to pass through the material, a rotation of polarization of the light, at an outlet from the plates, depending on the twist imparted to the nematic director.

An electro-optical method using liquid crystals comprising the steps of:

• filling a space between two parallel transparent plates with a material which comprises molecules having nematic properties;
• conferring on said material a structure defining a nematic director curved at least once in a plane perpendicular to the plates such that the nematic director arrives substantially perpendicularly at at least one of the two plates, and applying to the material an electrical field which is oblique with respect to the said plates in order to give preference to a particular area of structure of said material;
• imparting a twist to the nematic director along a component at right angles to said plane perpendicular to the plates;
• and
• causing light arriving with an incidence substantially at right angles to one of the plates to pass through the material, a rotation of polarization of the light, at an outlet from the plates, depending on the twist imparted to the nematic director.

An electro-optical method using liquid crystals comprising the steps of:

• filling a space between two parallel transparent plates with a material which comprises molecules having nematic properties and non-vanishing flexoelectric anisotropy;
• conferring on said material a structure defining a nematic director curved at least once in a plane perpendicular to the said plates such that the nematic director arrives substantially perpendicularly at at least one of the two plates;
• imparting a twist to the nematic director along a component at right angles to said plane perpendicular to the plates with application to the material of a low frequency electrical field parallel to the plates, and with simultaneous application of a high frequency electrical field;
• and
• causing light arriving with an incidence substantially at right angles to one of the plates to pass through the material, a rotation of polarization of the light, at an outlet from the plates, depending on the twist imparted to the nematic director.

An electro-optical method using liquid crystals comprising the steps of:

• filling a space between two parallel transparent plates with a material which comprises molecules having nematic porperties and non-vanishing flexoelectric anisotropy;
• conferring on said material a structure defining a nematic director curved at least once in a plane perpendicular to the said plates such that the nematic director arrives substantially perpendicularly at at least one of the two plates;
• imparting a twist to the nematic director along a component at right angles to said plane perpendicular to the plates with application to the material of a continuous electrical field parallel to the plates, and with simultaneous application of a high frequency electrical field;
• and
• causing light arriving with an incidence substantially at right angles to one of the plates to pass through the material, a rotation of polarization of the light, at an outlet from the plates, depending on the twist imparted to the nematic director.