Liquid crystal display with two separate power sources for the scan and signal drive circuits

A matrix-type liquid crystal display device comprising:

• a liquid crystal panel having a first set of n strip-shaped scanning electrodes and a second set of m strip-shaped signal electrodes, said first and second sets of electrodes being disposed perpendicular to each other and having pixels disposed at intersections therebetween for performing matrix display;
• a scanning electrode driving circuit for applying a scanning signal to said first set of n electrodes;
• a signal electrode driving circuit for applying a data signal to said second set of m electrodes;
• a scanning signal power supply circuit for outputting plural level scanning signal production voltages for producing said scanning signal;
• a data signal power supply circuit for outputting plural level data signal production voltages for producing said data signal;
• a first power supply circuit for performing power supply to said scanning electrode driving circuit and said scanning signal power supply circuit;
• and
• a second power supply circuit for supplying power to said signal electrode driving circuit and said data signal power supply circuit;
• wherein an average of said plural level scanning voltages is approximately equal to an average of said plural level data signal production voltages.

A matrix-type liquid crystal display device comprising:

• a liquid crystal panel having a first set of n strip-shaped scanning electrodes and a second set of m strip-shaped signal electrodes, said first and second sets of electrodes being disposed perpendicular to each other and having pixels disposed at intersections therebetween for performing matrix display;
• a scanning electrode driving circuit for applying a scanning signal to said first set of n scanning electrodes;
• a signal electrode driving circuit for applying a data signal to said second set of m signal electrodes;
• a scanning signal power supply circuit for outputting plural level scanning signal production voltages for producing said scanning signal;
• a first power supply circuit for performing power supply to said scanning electrode driving circuit and said scanning signal power supply circuit;
• a second power supply circuit for performing power supply to said signal electrode driving circuit;
• and
• an amplifier circuit for amplifying an image data signal input from an external source and outputting an image signal voltage;
• wherein said signal electrode driving circuit samples and inputs an image signal voltage from said amplifier circuit and outputs said data signal;
• and
• said amplifier circuit amplifies said image data signal with a predetermined level scanning signal production voltage output from said scanning signal power supply circuit as a reference.

A matrix-type liquid crystal display device comprising:

• a liquid crystal panel having a first set of n strip-shaped scanning electrodes and a second set of m strip-shaped signal electrodes, said first and second sets of electrodes being disposed perpendicular to each other and having pixels disposed at intersections therebetween for performing matrix display;
• scanning electrode driving means for applying a scanning signal to said first set of n scanning electrodes;
• signal electrode driving means for applying a data signal to said second set of m signal electrodes;
• a scanning electrode power supply for powering said scanning electrode driving means;
• a signal electrode power supply, separate from said scanning electrode power supply, for powering said signal electrode driving means;
• wherein said scanning electrode driving means comprises a scanning signal power supply circuit for outputting a power supply voltage for producing said scanning signal and a scanning electrode driving circuit for producing and outputting said scanning signal by means of said power supply voltage from said scanning signal power supply circuit;
• and
• said signal electrode driving means obtains voltage information indicating a state of a power supply voltage of said scanning signal power supply circuit and produces said data signal based on said voltage information.

A matrix-type liquid crystal display device comprising:

• a liquid crystal panel having a first set of n strip-shaped scanning electrodes and a second set of m strip-shaped signal electrodes, said first and second sets of electrodes being disposed perpendicular to each other and having pixels disposed at intersections therebetween for performing matrix display;
• scanning electrode driving means for applying a scanning signal to said first set of n scanning electrodes;
• and
• signal electrode driving means for applying a data signal to said second set of m signal electrodes;
• a scanning electrode power supply for powering said scanning electrode driving means;
• a signal electrode power supply, separate from said scanning electrode power supply, for powering said signal electrode driving means;
• wherein said signal electrode driving means includes modifying means for direct current modifying only a fluctuating portion of said data signal when said scanning signal direct current fluctuates.

A matrix-type liquid crystal display device comprising:

• a liquid crystal panel having a first set of n strip-shaped electrodes and a second set of m strip-shaped second electrodes, said first and second sets of electrodes being disposed perpendicular to each other and having pixels disposed at intersections therebetween for performing matrix display;
• a first electrode driving circuit for applying a signal to said first set of electrodes;
• and
• a second electrode driving circuit for applying a signal to said second set of electrodes;
• a first electrode power supply circuit for generating first electrode driving voltages to power said first electrode driving circuit, said first electrode driving voltages including a central voltage component, one of said first electrode driving voltages having a first polarity with respect to said central voltage component and others of said first electrode driving voltages having a polarity opposite that of said first polarity;
• a second electrode power supply circuit, separate from said first electrode power supply circuit, for receiving said central voltage component and for generating second electrode driving voltages to power said second electrode driving circuit, one of said second electrode driving voltages having a first polarity with respect to said central voltage component and others of said second electrode driving voltages having a polarity opposite that of said first polarity.