Low power pixel-based visual display device having dynamically changeable number of grayscale shades

A driver for a visual display device comprising:

• m n-bit/pixel frame buffers to hold m sets of pixel data, where m>1 and n>1;
• and
• an n-bit controller for switching among the m n-bit/pixel frame buffers at a selected rate during a display cycle to output a composite stream of the m sets of pixel data, the controller accessing each n-bit/pixel frame buffer multiple times during the display cycle wherein the number of accesses made by the controller is as follows:
• No. of Accesses=(2.sup.n -1).

A driver for a visual display device, comprising:

• two 2-bit/pixel frame buffers (m=2, n=2) to hold two sets of pixel data;
• and
• a 2-bit controller for switching among the two 2-bit/pixel frame buffers at a selected rate during a display cycle such that the controller three times accesses the two bits of pixel data in each frame buffer during the display cycle;
• and
• the driver being capable of producing seven grayscale shades.

A visual display device, comprising:

• m n-bit/pixel frame buffers to hold m sets of pixel data, where m>1 and n>1;
• an n-bit controller for switching among the m n-bit/pixel frame buffers at a selected rate during a display cycle to output a composite stream of the m sets of pixel data;
• a display coupled to the controller to receive the composite stream, the display having a matrix of pixels which turn on and off in response to the pixel data, individual pixels having a grayscale shade reflecting an average duration that the individual pixel is on;
• and
• the visual display device producing a number of grayscale shades, including white, as follows:
• No. of Shades=m.times.(2.sup.n -1)+1.

A visual display device, comprising:

• two 2-bit/pixel frame buffers (m=2, n=2) to hold two sets of pixel data;
• a 2-bit controller for switching among the two 2-bit/pixel frame buffers at a selected rate during a display cycle such that the controller three times accesses the two bits of pixel data in each frame buffer during the display cycle to output a composite stream;
• a display coupled to the controller to receive the composite stream, the display having a matrix of pixels which turn on and off in response to the pixel data, individual pixels having a grayscale shade reflecting an average duration that the individual pixel is on;
• and
• the visual display device being capable of producing seven grayscale shades.

A method for operating a visual display device, comprising the following steps:

• storing m sets of pixel data in m n-bit/pixel frame buffers, where m>1;
• switching among the m frame buffers during a display cycle;
• intermittent of said switching, accessing each of the m frame buffers multiple times during the display cycle to retrieve a corresponding set of pixel data;
• and
• displaying pixels having one of m.times.(2.sup.n -1)+1 grayscale shades reflecting an average of the m sets of pixel data retrieved from the m frame buffers.

A method for operating a visual display device, comprising the following steps:

• storing m sets of pixel data in m n-bit/pixel frame buffers, where m>1;
• switching among the m frame buffers during a display cycle;
• intermittent of said switching, accessing each of the m frame buffers 2.sup.n -1 times during the display cycle, where n>1, to retrieve a corresponding set of pixel data;
• and
• displaying pixels having grayscale shades reflecting an average of the m sets of pixel data retrieved from the m frame buffers.