Liquid crystal display device having an improved video line driver circuit

A liquid crystal display device comprising a liquid crystal display element having a plurality of pixels arranged in a matrix and a plurality of video signal lines for applying a video signal voltage to each of said plurality of pixels in accordance with a display data, and a video signal line driver circuit for supplying said video signal voltages to said plurality of video signal lines,

• said video signal line driver circuit including
• a gray-scale voltage generating circuit provided with a voltage-dividing resistor circuit for dividing voltages between a plurality of gray-scale reference voltages supplied from an external power supply circuit so as to generate a plurality of gray-scale voltages,
• a plurality of selector circuits corresponding to said plurality of video signal lines for selecting one gray-scale voltage from among said plurality of gray-scale voltages in accordance with said display data,
• said voltage-dividing resistor circuit including
• a resistive element provided with a plurality of intermediate taps for dividing voltages between said plurality of gray-scale reference voltages so as to generate said plurality of gray-scale voltages,
• a plurality of gray-scale voltage lines corresponding to said plurality of gray-scale voltages,
• an interlayer insulating film for insulating said plurality of gray-scale lines from said resistive element, and
• a plurality of connections for electrically connecting each of said plurality of gray-scale voltage lines to a corresponding one of said plurality of intermediate taps through a hole formed in said interlayer insulating film,
• each of said plurality of intermediate taps forming a portion protruding in a direction of extension of said plurality of gray-scale voltage lines, from said resistive element and each of said plurality of connections being disposed on said protruding portion.

A liquid crystal display device comprising a liquid crystal display element having a plurality of pixels arranged in a matrix and a plurality of video signal lines for applying a video signal voltage to each of said plurality of pixels in accordance with a display data, and a video signal line driver circuit for supplying said video signal voltage to said plurality of video signal lines,

• said video signal line driver circuit including:
• a plurality, of amplifiers corresponding to said plurality of video signal lines,
• each of said plurality of amplifiers outputting said video signal voltage to a corresponding one of said plurality of video signal lines, and
• a bias circuit including a current mirror circuit for controlling a current in a constant-current source in each of said plurality of amplifiers,
• said current mirror circuit including, between a first power supply voltage line supplied with a first reference power supply voltage and a second power supply voltage line supplied with a second reference power supply voltage:
• a first transistor element of a first conductivity type and having a low breakdown voltage,
• a second transistor element of a second conductivity type and having a breakdown voltage higher than said low breakdown voltage, said second transistor element being connected in series with said first transistor element, and
• at least one third transistor element of said first conductivity type, having a breakdown voltage higher than said low breakdown voltage, said at least one third transistor element being connected between said first transistor element and said second transistor element and having a fixed bias voltage applied to a control electrode thereof, said fixed bias voltage being between said first and second reference power supply voltages.

A liquid crystal display device comprising a liquid crystal display element having a plurality of pixels arranged in a matrix and a plurality of video signal lines for applying a video signal voltage to each of said plurality of pixels in accordance with a display data, and a video signal line driver circuit for supplying said video signal voltage to said plurality of video signal lines,

• said video signal line driver circuit including:
• a plurality of amplifiers corresponding to said plurality of video signal lines,
• each of said plurality of amplifiers outputting said video signal voltage to a corresponding one of said plurality of video signal lines, and a bias circuit including a current mirror circuit for controlling a current in a constant-current source in each of said plurality of amplifiers,
• said current mirror circuit including, between a first power supply voltage line supplied with a first reference power supply voltage and a second power supply voltage line supplied with a second reference power supply voltage:
• a first transistor element of a first conductivity type and having a low breakdown voltage,
• a second transistor element of a second conductivity type and having a breakdown voltage higher than said low breakdown voltage, said second transistor element being connected in series with said first transistor element, and
• at least one third transistor element of said first conductivity type, having a breakdown voltage higher than said low breakdown voltage, said at least one third transistor element being connected between said first transistor element and said second transistor element and having a control electrode thereof connected to a terminal thereof connected to said second transistor element.

A liquid crystal display device comprising a liquid crystal display element having a plurality of pixels arranged in a matrix and a plurality of video signal lines for applying a video signal voltage to each of said plurality of pixels in accordance with a display data, and a video signal line driver circuit for supplying said video signal voltage to said plurality of video signal lines,

• said video signal line driver circuit including
• a plurality of amplifiers corresponding to said plurality of video signal lines,
• each of said-plurality of amplifiers outputting said video signal voltage to a corresponding one of said plurality of video signal lines, and,
• a bias circuit for controlling a current in a constant-current source in each of said plurality of amplifiers,
• said bias-circuit including
• (a) a first series combination comprising:
• a first transistor element of a first conductivity type and having a first low breakdown voltage;
• a second transistor element of a second conductivity type and having a breakdown voltage higher than said first low breakdown voltage, said second transistor element being connected in series with said first transistor element;
• and at least one third transistor element of said first conductivity type and having a breakdown voltage higher than said first low breakdown voltage, said at least one third transistor element being connected between said first transistor element and said second transistor element;
• a terminal of said second transistor element connected to said at least one third transistor element being connected to a control electrode of said second transistor element, and
• a control electrode of said first transistor element being supplied with a bias voltage;
• (b) a second series combination comprising:
• a fourth transistor element of said first conductivity type and having a second low breakdown voltage;
• a fifth transistor element of said second conductivity type and having a breakdown voltage higher than said second low breakdown voltage, said fifth transistor element being connected in series with said fourth transistor element;
• and
• at least one sixth transistor element of said first conductivity type and having a breakdown voltage higher than said second low breakdown voltage, said at least one sixth transistor element being connected between said fourth transistor element and said fifth transistor element;
• a control electrode of said fifth transistor element being connected to said control electrode of said second transistor element,
• a terminal of said fourth transistor element connected to said at least one sixth transistor element being connected to a control electrode of said fourth transistor element, and
• a control electrode of said fourth transistor element being configured so as to provide an output;
• wherein a parallel combination of said first series combination and said second series combination is connected between a first power supply voltage line supplied with a first reference power supply voltage and a second power supply voltage line supplied with a second reference power supply voltage, and a voltage intermediate between said first and second reference power supply voltages is applied to control electrodes of said at least one third transistor element and said at least one sixth transistor element.

A liquid crystal display device comprising a liquid crystal display-element having a plurality of pixels arranged in a matrix and a plurality of video signal lines for applying a video signal voltage to each of said plurality of pixels in accordance with a display data, and a video signal line driver circuit for supplying said video signal voltage to said plurality of video signal lines,

• said video signal line driver circuit including
• a plurality of amplifiers corresponding to said plurality of video signal lines,
• each of said plurality of amplifiers outputting said video signal voltage to a corresponding one of said plurality of video signal lines, and
• a bias circuit for controlling a current in a constant-current source in each of said plurality of amplifiers,
• said bias circuit including
• (a) a first series combination comprising:
• a first transistor element of a first conductivity type and having a first low breakdown voltage;
• a second transistor element of a second conductivity type and having a breakdown voltage higher than said first low breakdown voltage, said second transistor element being connected in series with said first transistor element;
• and
• at least one third transistor element of said first conductivity type and having a breakdown voltage higher than said first low breakdown voltage, said at least one third transistor element being connected between said first transistor element and said second transistor element;
• a terminal of said second transistor element connected to said at least one third transistor element being connected to a control electrode of said second transistor element, and
• a control electrode of said first transistor element being supplied with a bias voltage;
• (b) a second series combination comprising:
• a fourth transistor element of said first conductivity type and having a second low breakdown voltage;
• a fifth transistor element of said second conductivity type and having a breakdown voltage higher than said second low breakdown voltage, said fifth transistor element being connected in series with said fourth transistor element;
• and
• at least one sixth transistor element of said first conductivity type and having a breakdown voltage higher than said second low breakdown voltage, said at least one sixth transistor element being connected between said fourth transistor element and said fifth transistor element;
• a control electrode of said fifth transistor element being connected to said control electrode of said second transistor element,
• a terminal of said fourth transistor element connected to said at least one sixth transistor element being connected to a control electrode of said fourth transistor element, and
• a control electrode of said fourth transistor element being configured so as to provide an output;
• wherein a parallel combination of said first series combination and said second series combination is connected between a first power supply voltage line supplied with a first reference power supply voltage and a second power supply voltage line supplied with a second reference power supply voltage,
• a control electrode of said at least one third transistor element is connected to a terminal of said at least one third transistor element connected to said second transistor element, and
• a control electrode of said at least one sixth transistor element is connected to a terminal of said at least one sixth transistor element connected to said fifth transistor element.

A liquid crystal display device comprising a liquid crystal display element having a plurality of pixels arranged in a matrix and a plurality of video signal lines for applying a video signal voltage to each of said plurality of pixels in accordance with a display data, and a video signal line driver circuit for supplying said video signal voltage to said plurality of video signal lines,

• said video signal line driver circuit including:
• a plurality, of amplifiers corresponding to said plurality of video signal lines,
• each of said plurality of amplifiers outputting said video signal voltage to a corresponding one of said plurality of video signal lines, and
• a bias circuit including a current mirror circuit for controlling a current in a constant-current source in each of said plurality of amplifiers,
• said current mirror circuit including, between a first power supply voltage line supplied with a first reference power supply voltage and a second power supply voltage line supplied with a second reference power supply voltage, means for preventing variations in current produced by the bias circuit, said means comprising:
• a first transistor element of a first conductivity type and having a low breakdown voltage,
• a second transistor element of a second conductivity type and having a breakdown voltage higher than said low breakdown voltage, said second transistor element being connected in series with said first transistor element, and
• at least one third transistor element of said first conductivity type, having a breakdown voltage higher than said low breakdown voltage, said at least one third transistor element being connected between said first transistor element and said second transistor element and having a fixed bias voltage applied to a control electrode thereof, said fixed bias voltage being between said first and second reference power supply voltages.

A liquid crystal display device comprising a liquid crystal display element having a plurality of pixels arranged in a matrix and a plurality of video signal lines for applying a video signal voltage to each of said plurality of pixels in accordance with a display data, and a video signal line driver circuit for supplying said video signal voltage to said plurality of video signal lines,

• said video signal line driver circuit including:
• a plurality of amplifiers corresponding to said plurality of video signal lines,
• each of said plurality of amplifiers outputting said video signal voltage to a corresponding one of said plurality of video signal lines, and a bias circuit including a current mirror circuit for controlling a current in a constant-current source in each of said plurality of amplifiers,
• said current mirror circuit including, between a first power supply voltage line supplied with a first reference power supply voltage and a second power supply voltage line supplied with a second reference power supply voltage, means for preventing variations in current produced by the bias circuit, said means comprising:
• a first transistor element of a first conductivity type and having a low breakdown voltage,
• a second transistor element of a second conductivity type and having a breakdown voltage higher than said low breakdown voltage, said second transistor element being connected in series with said first transistor element, and
• at least one third transistor element of said first conductivity type, having a breakdown voltage higher than said low breakdown voltage, said at least one third transistor element being connected between said first transistor element and said second transistor element and having a control electrode thereof connected to a terminal thereof connected to said second transistor element.