Electro-optic display device with increased number of transmission levels
AssigneeU.S. Philips Corporation
InventorsWilbert J. A. M. Hartmann, Leonard J. M. Esser, Antonius G. H. Verhulst, Johannes A. M. M. Van Haaren
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Abstract
An LCD device in which the pixels are divided into sub-pixels composed of one analog adjustable sub-pixel and a plurality of digitally controlled other sub-pixels. By combining a discrete adjustment of the (sub)-transmission levels of the other sub-pixels with an analog adjustment of transmission levels of the one sub-pixel, the total number of light transmission levels is increased considerably. The analog adjustment thus is less critical because the greater part of the ultimate level is defined by the accurate discrete adjustment.
Claims22
A display device comprising:
- an electro-optical medium positioned between two supporting plates in which pixels are divided into a plurality of sub-pixels that are defined on at least one of the supporting plates by means of picture electrodes, characterized in that for a pixel one sub-pixel thereof has a surface area which is at most equal to a surface area of one of the other sub-pixels of said same pixel and is adjustable at a plurality of transmission levels greater than two, while the other sub-pixels of said pixel are exclusively switchable between two extreme transmission states.
A gray-scale display device comprising:
- first and second support plates with an electro-optical material located therebetween,
- a first and second plurality of picture electrodes arranged on said first and second support plates, respectively, so as to define a plurality of pixels, said picture electrodes being further arranged so as to divide the pixels into respective pluralities of sub-pixels wherein each pixel includes one given sub-pixel having a surface area which is at most equal to the surface area of one other of its sub-pixels, said one given sub-pixel having a light transmission characteristic which is varied over a plurality of light transmission levels greater than two, and
- means for selectively applying binary type switching voltages to the other sub-pixels such that the other sub-pixels are only switchable between two extreme light transmission states.
Dependencies are inferred from the claim text.