Current signal output circuit and display apparatus and information display apparatus using the current signal output circuit

A current signal output circuit for outputting a current signal in accordance with an inputted voltage signal comprising:

• a current signal control circuit,
• said current signal control circuit comprising:
• at least a first through an eighth switch, a first and a second capacitor element and a first through a fourth transistor;
• wherein a first terminal of the first switch is connected to a voltage signal line for providing the voltage signal and a second terminal of the first switch is connected to a first terminal of the first capacitor element,
• a second terminal of the first capacitor element is connected to a gate electrode of the first transistor,
• a first terminal and a second terminal of the third switch are respectively connected to the gate electrode and a second main electrode of the first transistor,
• a first main electrode of the first transistor is connected to a first power source,
• the second main electrode of the first transistor is connected to a first terminal of the fourth switch and a first terminal of the seventh switch,
• a second terminal of the seventh switch is connected to a first main electrode of the third transistor,
• a gate electrode and the first main electrode or a second main electrode of the third transistor are shortcircuited and the second main electrode is connected to a second power source,
• a first terminal of the second switch is connected to the voltage signal line for providing the voltage signal,
• a second terminal of the second switch is connected to a first terminal of the second capacitor element,
• a second terminal of the second capacitor element is connected to a gate electrode of the second transistor,
• a first terminal and a second terminal of the fifth switch are respectively connected to the gate electrode and a second main electrode of the second transistor,
• a first main electrode of the second transistor is connected to the first power source,
• the second main electrode of the second transistor is connected to a first terminal of the sixth switch and a first terminal of the eighth switch,
• a second terminal of the eighth switch is connected to a first main electrode of the fourth transistor,
• a gate electrode and the first main electrode or a second main electrode of the fourth transistor are shortcircuited and the second main electrode is connected to a second power source,
• second terminals of the fourth and the sixth switches are connected to each other to constitute a current signal output terminal for outputting the current signal to outside, and
• control terminals of the first through the eighth switches are respectively connected to a first through an eighth control signal line.

A current signal output circuit for outputting a current signal in accordance with an inputted voltage signal comprising:

• a current signal control circuit,
• said current signal control circuit comprising:
• at least a first and a second switch, a first capacitor element, and a first transistor;
• wherein a first terminal of the first switch is connected to a voltage signal line for providing the voltage signal, a second terminal of the first switch is connected to a first terminal of the first capacitor element,
• a second terminal of the first capacitor element is connected to a gate electrode of the first transistor,
• a first terminal and a second terminal of the third switch are respectively connected to the gate electrode and a second main electrode of the first transistor, and
• a first main electrode of the first transistor is connected to a first power source,
• wherein the gate electrode of the first transistor is charged via the second switch and discharged such that a voltage of the gate electrode of the first transistor becomes proximate to a threshold voltage and thereafter, the gate electrode of the first transistor is charged to a voltage in accordance with the voltage signal provided to the first switch and the current signal in accordance with the charged state is outputted from the second main electrode as the current signal.

A current signal output circuit for outputting a current signal in accordance with an inputted voltage signal comprising:

• a current signal control circuit,
• said current signal control circuit comprising:
• at least a first switch, a first capacitor element and a first transistor;
• wherein a first terminal of the first switch is connected to a voltage signal line for providing the voltage signal, a second terminal of the first switch is connected to a first terminal of the first capacitor element,
• a second terminal of the first capacitor element is connected to a gate electrode of the first transistor, and
• the first main electrode of the first transistor is connected to a first power source,
• wherein the gate electrode is discharged such that a voltage of the gate electrode of the first transistor becomes proximate to a threshold voltage, thereafter the gate electrode of the first transistor is charged to a voltage in accordance with the voltage signal provided to the first switch and the current signal is outputted in accordance with the charged state from the second main electrode of the first transistor.

An electroluminescence apparatus comprising:

• a plurality of pixel circuits comprising an electroluminescence element, a driving transistor for providing driving current to drive the electroluminescence element and a capacitor connected to a gate of the driving transistor, and
• a column control circuit comprising a transistor, a first switch for providing a voltage signal to a gate of the transistor through a capacitor element, a switch means for connecting the gate of the transistor to a reference voltage source, and a second switch for providing a current signal to the plurality of pixel circuits from the transistor;
• wherein the current signal provided to the pixel circuit from the column control circuit is held by a capacitor of the pixel circuit as a charging voltage, and the driving transistor provides the driving current to the electroluminescence element based on the charging voltage held by the capacitor;
• wherein the column control circuit executes steps of:
• inputting a voltage of blanking level to the capacitor element through the first switch while connecting the gate of the transistor to the reference voltage source by the switch means,
• inputting a video voltage through the first switch while disconnecting the gate of the transistor from the reference voltage source by the switch means so that a voltage is held by a gate capacitance of the transistor, and
• providing the current signal to the plurality of pixel circuits through the second switch according to the held voltage.

An electroluminescence apparatus comprising:

• first and second pixel circuits, each of which comprising an electroluminescence element, a driving transistor for providing driving current to drive the electroluminescence element and a capacitor connected to a gate of the driving transistor;
• a first column control circuit comprising a first transistor, a first switch for providing a voltage signal to a gate of the first transistor, and a second switch for providing a current signal to the first pixel circuit from the first transistor based on the voltage signal provided to the gate of the first transistor;
• and
• a second column control circuit comprising a second transistor, a third switch for providing a voltage signal to a gate of the second transistor and a fourth switch for providing a current signal to the second pixel circuit from the second transistor based on the voltage signal provided to the gate of the second transistor;
• wherein the current signals provided to the first and second pixel circuits from the first and the second column control circuits are held by a capacitor of the pixel circuits as a charging voltage, and the driving transistor provides the driving current to the electroluminescence element based on the charging voltage held by the capacitor;
• wherein the first and second column control circuits;
• provides the current signal to the second pixel circuit through the fourth switch while providing a video signal to the gate of the first transistor through the first switch;
• and
• provides the current signal to the first pixel circuit through the second switch while providing a video signal to the gate of the second transistor through the third switch.