Methods for addressing electrophoretic displays

A method of addressing a bistable display, this display comprising a set of display elements each having first and second display states differing in at least one optical property, the method comprising:

• (a) causing the display to display a first image in which a first subset of display elements are in their first display state and the complement of the first subset of display elements are in their second display state;
• (b) applying to the first subset of display elements, but not to the complement of the first subset, a first addressing signal, thereby causing the first subset to assume their second display state;
• and
• (c) applying to a second subset of display elements, different from said first subset, but not to the complement of the second subset, a second addressing signal, thereby causing the second subset to assume their first display state and the display to display a second image, different from the first image, the second image being formed by the second subset of display elements being in their first display state and the complement of the second subset being in their second display state.

A method of addressing a bistable display, this display comprising a set of display elements each having first and second display states differing in at least one optical property, the method comprising:

• (a) selecting a first subset of display elements that represent a first image, and applying to the first subset a first addressing signal, thereby causing the first subset to assume their first display state and the display to display the first image;
• (b) selecting a second subset of display elements that represent a second image different from the first image and thereby defining four classes of display elements, namely a first class which are members of both the first and second subsets, a second class which are members of the first subset but not members of the second subset, a third class which are not members of the first subset but are members of the second subset, and a fourth class which are not members of either the first or the second subset, and applying to the second class a second addressing signal, thereby setting the second class to their second display state, and applying to the third class a third addressing signal, thereby setting the third class to their first display state, and causing the display to display the second image,
• and wherein the display has on one side thereof a common electrode extending across all the display elements of the set, and on the opposed side thereof a plurality of discrete electrodes, one of the discrete electrodes being associated with each display element of the set, the common electrode being kept at a substantially constant first voltage during steps (a) and (b).

A method of addressing a bistable display comprising a set of display elements each having first and second display states differing in at least one optical property, the display having on one side thereof a common electrode extending across all the display elements of the set, and on the opposed side thereof a plurality of discrete electrodes, one of the discrete electrodes being associated with each display element of the set, the method comprising:

• (a) selecting a first subset of display elements that represent a first image;
• (b) selecting a second subset of display elements that represent a second image different from the first image and thereby defining four classes of display elements, namely a first class which are members of both the first and second subsets, a second class which are members of the first subset but not members of the second subset, a third class which are not members of the first subset but are members of the second subset, and a fourth class which are not members of either the first or the second subset,
• (c) bringing the display to a state in which the first and classes of display elements are in their first display state and the third and fourth classes are in their second display state, thereby causing the first image to be displayed;
• and
• (d) applying a first voltage to the common electrode for a first period and a different second voltage to the common electrode for a second period, while maintaining the discrete electrodes associated with at least one of the first and fourth classes of display elements at substantially the same voltages as the common electrode, and maintaining the discrete electrodes associated with one of the second and third classes of display elements substantially at the first voltage while maintaining the discrete electrodes associated with the other of the second and third classes substantially at the second voltage,
• thereby causing the first and third classes of display elements to be in their first display state and the second and fourth classes of display elements to be in their second display state, so that the display displays the second image.