Image display device
View Patent ↗An image display device in which a plurality of pixel circuits are arranged has a current light-emitting element, a driver transistor for flowing current in the current light-emitting element, a retention capacitor for retaining a voltage determining an amount of current flowed from the driver transistor, and a writing switch for writing a voltage depending on an image signal to the retention capacitor. Transistors configuring the respective pixel circuits are an N-channel type transistor, each of the pixel circuits further includes an enable switch, an initialization capacitor for initializing the voltage of the retention capacitor, and a separation switch.
1. An image display device, comprising:
a pixel circuit, the pixel circuit including:
a current light-emitting element;
an N-type driver transistor for flowing current in the current light-emitting element;
a retention capacitor for retaining a retention voltage applied to the N-type transistor;
an N-type writing switch transistor for writing the retention voltage to the retention capacitor based on an image signal;
an N-type enable switch transistor wherein a drain of the N-type enable switch transistor is connected to a source of the N-type driver transistor and a source of the N-type enable switch transistor is connected to an anode of the current light-emitting element;
an initialization capacitor; and
an N-type separation switch transistor,
wherein a first electrode of the retention capacitor is connected to a gate of the N-type driver transistor and a second electrode of the retention capacitor is connected to a first electrode of the initialization capacitor,
wherein a second electrode of the initialization capacitor is connected to a trigger line, the trigger line supplying a trigger signal for initializing the retention voltage of the retention capacitor,
wherein a drain of the N-type separation switch transistor is connected to the second electrode of the retention capacitor and the first electrode of the initialization capacitor, and
wherein a source of the N-type separation switch transistor is connected to a source of the N-type driver transistor.
2. The image display device according to claim 1 ,
wherein the trigger signal supplied to the trigger line is a control signal for controlling the N-type enable switch transistor.
3. The image display device according to claim 1 ,
wherein the pixel circuit further includes an N-type reference switch transistor for applying a reference voltage to the gate of the N-type driver transistor.
4. The image display device according to claim 1 , further comprising:
a plurality of pixel circuits.
5. A pixel circuit, comprising:
a current light-emitting element;
an N-type driver transistor for flowing current in the current light-emitting element;
a retention capacitor for retaining a retention voltage applied to the N-type transistor;
an N-type writing switch transistor for writing the retention voltage to the retention capacitor based on an image signal;
an N-type enable switch transistor wherein a drain of the N-type enable switch transistor is connected to a source of the N-type driver transistor and a source of the N-type enable switch transistor is connected to an anode of the current light-emitting element;
an initialization capacitor; and
an N-type separation switch transistor,
wherein a first electrode of the retention capacitor is connected to a gate of the N-type driver transistor and a second electrode of the retention capacitor is connected to a first electrode of the initialization capacitor,
wherein a second electrode of the initialization capacitor is connected to a trigger line, the trigger line supplying a trigger signal for initializing the retention voltage of the retention capacitor,
wherein a drain of the N-type separation switch transistor is connected to the second electrode of the retention capacitor and the first electrode of the initialization capacitor, and
wherein a source of the N-type separation switch transistor is connected to a source of the N-type driver transistor.
6. The image display device according to claim 1 ,
wherein the first electrode of the initialization capacitor generates voltage change of ΔV·C 2 /(C 1 +C 2 ),
where C 1 is a capacitance of the retention capacitor, C 2 is a capacitance of the initialization capacitor, and ΔV is adjusted so that voltage of the retention capacitor is higher than threshold voltage of the N-type driver transistor.
7. The image display device according to claim 1 ,
wherein the gate of the N-type driver transistor is connected to a data line, and VC 1 =Vth+C 2 ·Vdata/(C 1 +C 2 ) is satisfied, where C 1 is a capacitance of the retention capacitor, C 2 is a capacitance of the initialization capacitor, VC 1 is voltage of the retention capacitor, Vth is a threshold voltage of the N-type driver transistor, and Vdata is a voltage supplied to the data line.