Semiconductor integrated circuit for driving liquid crystal panel
AssigneeFujitsu Limited
InventorsSeiji Yamagata, Masatoshi Kokubun, Shinya Udo
Life of this patent
Estimating the term…
Abstract
Lower level of data latch holding a digital image data and a positive selector arranged immediately above positive gradation voltage line, for selecting positive analog gradation voltage of positive gradation levels are take as a set, and upper level of data latch holding a digital image data and a negative selector arranged immediately above negative gradation voltage line, for selecting negative analog gradation voltage of negative gradation levels are take as a set. Two sets are arranged in alignment in vertical direction. A plurality of sets of vertically aligned sets are arranged horizontally to shorten a length in horizontal direction with respect to gradation voltage lines.
Claims18
A gradation wiring for a display comprising:
- wiring for respective gradation levels of a first gradation level range for outputting voltage of said first gradation level range when total number of gradation levels of the display is divided into a plurality of fractions;
- wiring for respective gradation level of a second gradation level range different from said first gradation level range, for outputting voltage of said second gradation level range and being arranged alternately with the wiring of respective gradation level of said first gradation level range.
A driver for a liquid crystal display comprising:
- wiring for respective gradation levels of a first gradation level range for outputting voltage of said first gradation level range when total number of gradation levels of the display is divided into a plurality of fractions;
- wiring for respective gradation level of a second gradation level range different from said first gradation level range, for outputting analog gradation voltage of respective gradation levels of said second gradation level range and being arranged alternately with the wiring of respective gradation level of said first gradation level range;
- a first ladder resistor connected between wiring of respective gradation levels of said first gradation level range;
- a second ladder resistor connected between wiring of respective gradation levels of said second gradation level range;
- a first reference voltage input terminal connected for making voltages of the wiring of said first gradation level range at the same potential;
- a second reference voltage input terminal connected for making voltages of the wiring of said second gradation level range at the same potential;
- and
- a decoder for converting input digital gradation value into an analog gradation value on the basis of the analog gradation voltage value output from the wiring of respective gradation levels of said first and second gradation level ranges.
A stress test method for a driver of a liquid crystal display having wiring for respective gradation levels of a first gradation level range for outputting voltage of said first gradation level range when total number of gradation levels of the display is divided into a plurality of fractions, and wiring for respective gradation level of a second gradation level range different from said first gradation level range, for outputting voltage of said second gradation level range and being arranged alternately with the wiring of respective gradation level of said first gradation level range, comprising the steps of:
- applying a first potential to wiring of a predetermined gradation level of said first gradation level range, applying a second potential to wiring of a predetermined gradation level of said second gradation level range, and whereby applying a stress voltage higher than the reference input voltage between said wiring;
- and
- applying said reference input voltages of respective gradation levels to the wiring of predetermined gradation levels of said first and second gradation level ranges and inspecting presence or absence of abnormality of output voltage by measuring voltages output from the wiring of overall gradation levels.
Dependencies are inferred from the claim text.