Field sequential color display system using optical retardation

Claim 1

A high-speed field sequential color display system, comprising: a light source that emits light rays of plural wavelengths; first and second light polarizing means in optical communication with the light source, the first light polarizing means including a color sensitive polarizing filter; liquid crystal variable optical retarding means disposed between the first and second light polarizing means; and switching means in communication with the variable optical retarding means to selectively provide first and second switching states to produce respective first and second amounts of optical retardation to develop over a relatively broad range of viewing angles a light output of one of two colors.

Claim 12

A method for using a liquid crystal cell as a relatively high-speed variable retardation device to vary the retardation of light propagating within the cell, the liquid crystal cell comprising liquid crystal material which has directors and is contained between a pair of opposed electrode structures, each electrode structure having an inner surface that includes a director alignment layer which has been conditioned so that the directors of the liquid crystal material in contact therewith become substantially uniformly aligned to form tilt bias angles with the conditioned surfaces, the tilt bias angles of the directors in contact with one conditioned surface being defined in a rotational sense opposite to the tilt bias angles of the directors in contact with the other conditioned surface, the steps comprising: providing within the cell an electric field of a character that causes alignment of at least some of the surface noncontacting directors to a first configuration to provide a first amount of optical retardation of the light propagating within the cell; and changing the character of the electric field within the cell to cause alignment of at least some of the surface noncontacting directors to a partly relaxed configuration defined by the intermolecular elastic forces within the cell to provide in a relatively short time a second amount of optical retardation of the light propagating within the cell.

Claim 13

A method for using a liquid crystal cell as a relatively high-speed variable retardation device to vary the retardation of light propagating within the cell, the liquid crystal cell comprising liquid crystal material which has directors and is contained between a pair of opposed electrode structures, each electrode structure having an inner surface that includes a director alignment layer which has been conditioned so that the directors of the liquid crystal material in contact therewith become substantially uniformly aligned to form tilt bias angles with the conditioned surfaces, the tilt bias angles of the directors in contact with one conditioned surface being defined in a rotational sense opposite to the tilt bias angles of the directors in contact with the other conditioned surface, the steps comprising: providing within the cell an electric field of a character that causes alignment of at least some of the surface noncontacting directors to a first configuration to provide a first amount of optical retardation of the light propagating within the cell; and changing the character of the electric field within the cell to cause alignment of at least some of the surface noncontacting directors to a partly relaxed configuration defined by the intermolecular elastic forces within the cell to provide in a relatively short time a second amount of optical retardation of the light propagating within the cell.

Claim 14

A method for using a liquid crystal cell as a relatively high-speed variable retardation device to vary the retardation of light transmitted therethrough from an external source, the liquid crystal cell comprising liquid crystal material which has directors and is contained between a pair of opposed electrode structures, the inner surface of each electrode structure including a director alignment layer which has been conditioned so that the directors of the liquid crystal material in contact therewith become substantially uniformly aligned to form tilt bias angles with the conditioned surface, the tilt bias angles of the directors in contact with one conditioned surface being defined in a rotational sense opposite to the tilt bias angles of the directors in contact with the other conditioned surface, the steps comprising: applying a first signal to the conductive layers of the cell to produce an electric field to cause a substantial number of the surface noncontacting directors to align essentially end-to-end in a direction normal to the conditioned surfaces to provide substantially reduced optical retardation through the cell of light incident to one of the surfaces of the electrode structures; and applying a second signal to the conductive layers of the cell to change the electric field to cause at least some of the surface noncontacting directors within the interior of the cell to recede from the end-to-end alignment to provide in a relatively short time essentially half-wave optical retardation of light incident to one of the surfaces of the electrode structures.

Claim 15

A method for using a liquid crystal cell as a relatively high-speed variable retardation device to vary the retardation of light transmitted therethrough from an external source, the liquid crystal cell comprising liquid crystal material which has directors and is contained between a pair of opposed electrode structures, the inner surface of each electrode structure including a director alignment layer which has been conditioned so that the directors of the liquid crystal material in contact therewith become substantially uniformly aligned to form tilt bias angles with the conditioned surface, the tilt bias angles of the directors in contact with one conditioned surface being defined in a rotational sense opposite to the tilt bias angles of the directors in contact with the other conditioned surface, the steps comprising: applying a first signal to the conductive layers of the cell to produce an electric field to cause a substantial number of the surface noncontacting directors to align essentially end-to-end in a direction normal to the conditioned surfaces to provide substantially reduced optical retardation through the cell of light incident to one of the surfaces of the electrode structures; and applying a second signal to the conductive layers of the cell to change the electric field to cause at least some of the surface noncontacting directors within the interior of the cell to recede from the end-to-end alignment to provide in a relatively short time essentially half-wave optical retardation of light incident to one of the surfaces of the electrode structures.

Claim 16

A method for using a liquid crystal cell as a relatively high-speed variable retardation device to modulate light transmitted therethrough from an external source, the liquid crystal cell comprising liquid crystal material which has directors and is contained between a pair of opposed electrode structures, the inner surface of each electrode structure including a director alignment layer which has been conditioned so that the directors of the liquid crystal material in contact therewith become substantially uniformly aligned to form tilt bias angles with the conditioned surfaces, the tilt bias angles of the directors in contact with one conditioned surface being defined in a rotational sense opposite to the tilt bias angles of the directors in contact with the other conditioned surface, the steps comprising: applying a first signal to the conductive layers of the cell to produce an electric field to cause a substantial number of the surface noncontacting directors to align essentially end-to-end in a direction normal to the conditioned surfaces to provide substantially reduced optical retardation through the cell for light incident to one of the electrode surfaces; and applying a second signal to the conductive layers of the cell to change the electric field and cause rotational realignment of the surface noncontacting directors to provide essentially half-wave optical retardation for light incident to one of the electrode surfaces, the rotational realignment of the surface noncontacting directors characterized in that such rotation causes a unidirectional flow of liquid crystal material within the cell to eliminate optical retardation bounce during realignment, thereby to decrease the optical response time of the cell.

Claim 17

A method for using a liquid crystal cell as a relatively high-speed variable retardation device to modulate light transmitted therethrough from an external source, the liquid crystal cell comprising liquid crystal material which has directors and is contained between a pair of opposed electrode structures, the inner surface of each electrode structure including a director alignment layer which has been conditioned so that the directors of the liquid crystal material in contact therewith become substantially uniformly aligned to form tilt bias angles with the conditioned surfaces, the tilt bias angles of the directors in contact with one conditioned surface being defined in a rotational sense opposite to the tilt bias angles of the directors in contact with the other conditioned surface, the steps comprising: applying a first signal to the conductive layers of the cell to produce an electric field to cause a substantial number of the surface noncontacting directors to align essentially end-to-end in a direction normal to the conditioned surfaces to provide substantially reduced optical retardation through the cell for light incident to one of the electrode surfaces; and applying a second signal to the conductive layers of the cell to change the electric field and cause rotational realignment of the surface noncontacting directors to provide essentially half-wave optical retardation for light incident to one of the electrode surfaces, the rotational realignment of the surface noncontacting directors characterized in that such rotation causes a unidirectional flow of liquid crystal material within the cell to eliminate optical retardation bounce during realignment, thereby to decrease the optical response time of the cell.

Claim 20

A method for providing a liquid crystal cell having nonuniform director alignment which can be used as a variable retardation device to accomplish with relatively short relaxation time the modulation of light transmitted therethrough from an external source, the steps comprising: applying an electrically conductive layer to one surface of each of two optically transparent dielectric members to form a pair of electrode structures; conditioning one surface of each of the pair of electrode structures so that the directors of a liquid crystal material placed thereon will align in a predetermined direction; positioning each electrode structure of the pair so that the conditioned surfaces thereof are in spaced-apart and opposed face-to-face relation; introducing a liquid crystal material between the electrode structures to form an anisotropic cell; orienting the electrode structures so that the directors of the liquid crystal material in contact with the conditioned surfaces align substantially uniformly to form tilt bias angles with the conditioned surfaces, the tilt bias angles of the directors in contact with one conditioned surface being defined in a rotational sense opposite to the tilt bias angles of the directors in contact with the other conditioned surface; and applying alternately to the cell a first signal to provide an electric field to cause a substantial number of the surface noncontacting directors to align in essentially end-to-end relation in a direction normal to the conditioned surfaces to provide substantially reduced optical retardation through the cell of light incident to one of the surfaces of the electrode structures, and a second signal to change the electric field to cause at least some of the surface noncontacting directors within the interior of the cell to recede from the end-to-end alignment to provide in a relatively short time essentially half-wave optical retardation of light incident to one of the surfaces of the electrode structures.

Claim 21

A method for providing a liquid crystal cell having nonuniform director alignment which can be used as a variable retardation device to accomplish with relatively short relaxation time the modulation of light transmitted therethrough from an external source, the steps comprising: applying an electrically conductive layer to one surface of each of two optically transparent dielectric members to form a pair of electrode structures; conditioning one surface of each of the pair of electrode structures so that the directors of a liquid crystal material placed thereon will align in a predetermined direction; positioning each electrode structure of the pair so that the conditioned surfaces thereof are in spaced-apart and opposed face-to-face relation; introducing a liquid crystal material between the electrode structures to form an anisotropic cell; orienting the electrode structures so that the directors of the liquid crystal material in contact with the conditioned surfaces align substantially uniformly to form tilt bias angles with the conditioned surfaces, the tilt bias angles of the directors in contact with one conditioned surface being defined in a rotational sense opposite to the tilt bias angles of the directors in contact with the other conditioned surface; and applying alternately to the cell a first signal to provide an electric field to cause a substantial number of the surface noncontacting directors to align in essentially end-to-end relation in a direction normal to the conditioned surfaces to provide substantially reduced optical retardation through the cell of light incident to one of the surfaces of the electrode structures, and a second signal to change the electric field to cause at least some of the surface noncontacting directors within the interior of the cell to recede from the end-to-end alignment to provide in a relatively short time essentially half-wave optical retardation of light incident to one of the surfaces of the electrode structures.