Ferroelectric display panel and driving method therefor to achieve gray scale

A display panel, comprising:

• a liquid crystal device comprising a plurality of picture elements arranged in a plurality of rows and columns, each picture element comprising a ferroelectric crystal under bistability condition showing either a first or a second orientation state,
• signal-application means for applying signals comprising a first signal for orienting the ferroelectric liquid crystal to the first orientation state and a second signal for orienting the ferroelectric liquid crystal to the second orientation state at respective picture elements on a row, and
• duration-controlling means for controlling the duration of the first or second orientation state at respective picture elements.

A display panel, comprising:

• a liquid crystal device comprising a plurality of picture elements arranged in a plurality of rows and columns, each picture element comprising a ferroelectric crystal under bistability condition showing either a first or a second orientation state,
• signal-application means for applying a first signal for orienting the ferroelectric liquid crystal to the first orientation state picture elements constituting the whole or a part of a picture thereby to clear the picture elements, and a second signal for orienting the ferroelectric liquid crystal to the second orientation state a selected picture element among the cleared picture elements to write a display state based on the second orientation state, said second signal being applied row by row, and
• duration-controlling means for controlling the duration of the first or second orientation state at respective picture elements.

A display panel, comprising:

• a liquid crystal device comprising a plurality of picture elements arranged in a plurality of rows and columns, each picture element comprising a ferroelectric crystal under bistability condition having a first orientation state and a second orientation state,
• writing means for writing a display state based on the first orientation state of the ferroelectric liquid crystal in a selected first group of picture elements row by row on the whole or a part of a picture in a first stage, and writing a display state based on the second orientation state of the ferroelectric liquid crystal in a selected second group of picture elements row by row on the whole or a part of a picture in a second stage, and
• duration-controlling means for controlling the duration of the first or second orientation state at respective picture elements.

In a method for driving a display panel of the type comprising a plurality of picture elements arranged two-dimensionally;

• the improved method comprising controlling display duty in a unit time period for each picture element thereby to provide a gradation.

In a method for driving a display panel of the type comprising a plurality of picture elements arranged in a plurality of rows and columns, each picture element comprising a ferroelectric liquid crystal under bistability condition showing either a first or a second orientation state, either one of the first and second orientation states being written in respective picture elements to effect a display;

• the improved method comprising controlling the duration of the first or second orientation state at respective picture elements.

In a method for driving a display panel of the type comprising a plurality of picture elements arranged in a plurality of rows and columns, each picture element comprising a ferroelectric liquid crystal under bistability condition showing either a first or a second orientation state, either one of the first and second orientation states being written in respective picture elements to effect a display;

• the improvement comprising:
• applying row by row a first signal for orienting the ferroelectric liquid crystal to the first orientation state at a selected picture element on a row and a second signal for orienting the ferroelectric liquid crystal to the second orientation state at the remaining picture elements on the row, and
• controlling the duration of the first or second orientation state at respective picture elements.

In a method for driving a display panel of the type comprising a plurality of picture elements arranged in a plurality of rows and columns, each picture element comprising a ferroelectric liquid crystal under bistability condition showing either a first or a second orientation state, either one of the first and second orientation states being written in respective picture elements to effect a display;

• the improvement comprising:
• applying row by row a first signal for orienting the ferroelectric liquid crystal to the first orientation state at the whole or a part of the picture elements on a row to clear the picture elements and a second signal for orienting the ferroelectric liquid crystal to the second orientation state at a selected picture element among the cleared picture elements on the row, and
• controlling the duration of the first or second orientation state at respective picture elements.

In a method for driving a display panel of the type comprising a plurality of picture elements arranged in a plurality of rows and columns, each picture element comprising a ferroelectric liquid crystal under bistability condition showing either a first or a second orientation state, either one of the first and second orientation states being written in respective picture elements to effect a display;

• the improvement comprising:
• applying row by row a first signal for orienting the ferroelectric liquid crystal to the first orientation state at the whole or a part of the picture elements on a row ((N+1)th row) subsequent to a writing row (Nth row) to clear the picture elements and a second signal for orienting the ferroelectric liquid crystal to the second orientation state at a selected picture element among the cleared elements on the writing row (Nth row), and
• controlling the duration of the first or second orientation state at respective picture elements.

In a method for driving a display panel of the type comprising a plurality of picture elements arranged in a plurality of rows and columns, each picture element comprising a ferroelectric liquid crystal under bistability condition showing either a first or a second orientation state, either one of the first and second orientation states being written in respective picture elements to effect a display;

• the improvement comprising:
• applying a first signal for orienting the ferroelectric liquid crystal to the first orientation state to picture elements constituting the whole or a part of a picture thereby to clear the picture elements, and a second signal for orienting the ferroelectric liquid crystal to the second orientation state to a selected picture element among the cleared picture elements, and
• controlling the duration of the first or second orientation state at respective picture elements.