Image display apparatus and method thereof

A monochrome liquid crystal display apparatus, comprising:

• a controller for outputting, from input monochrome data in which one pixel is represented with a plurality of sub-pixels, a gray level set for each of said plurality of sub-pixels;
• a liquid crystal cell for displaying a monochrome image;
• and
• a liquid crystal driver for supplying a voltage to said liquid crystal cell based on a gray level of said plurality of sub-pixels output from said controller without varying the liquid crystal transmittance for a particular gray level among said plurality of sub-pixels,
• wherein said controller assumes a characteristic for the particular sub-pixel in which no multiple of the brightness level of any intermediate gray level is identical to the brightness level of any intermediate gray level of another sub-pixel and selecting a gray revel which provides desired brightness from within said characteristic.

A controller for providing image data for each of said plurality of sub-pixels to a liquid crystal driver supplying a voltage to a liquid crystal cell by inputting data in which one pixel is represented by a plurality of sub-pixels, comprising:

• memory for storing information about an offset for converting gray level coordinates of a gamma characteristic spaced evenly according to the number of bits of said liquid crystal driver into gray level coordinates spaced unevenly;
• a gray level adjustment portion for performing a calculation on particular sub-pixel data based on information about said offset stored in said memory;
• and
• a pseudo-gray-level-expansion portion for applying pseudo gray level expansion to said sub-pixel data calculated by said gray level adjustment portion.

An image conversion method, comprising the steps of:

• inputting a plurality pieces of sub-pixel image data, each of said pieces of sub-pixel image data comprising N bits;
• assuming a second gamma characteristic corresponding to M bits (M>N) which is provided by adjusting a first gamma characteristic corresponding to N bits;
• selecting an appropriate gray level which provides desired brightness based on said second gamma characteristic for a particular piece of sub-pixel image data of said plurality pieces of sub-pixel image data and replacing its original gray level with the selected gray level;
• and
• providing said replaced gray level as an output value for said particular piece of sub-pixel image data.

An image display method for displaying a monochrome image having multiple gray levels by dividing one pixel into a plurality of sub-pixels, comprising the steps of:

• assuming a gamma characteristic of said sub-pixels in which no multiple of a brightness level of a intermediate gray level of said sub-pixel is identical to a brightness level of any intermediate gray level of another sub-pixel;
• selecting an appropriate gray level providing desired brightness based on said assumed gamma characteristic;
• and
• displaying the monochrome image based on said selected appropriate gray level.