Light emitting display device and driving control method therefor
A clock signal in synchronization with a data writing signal, every scanning line, which is supplied from a light-emitting control circuit 4 to a scanning driver 6 , is supplied to an oscillator 12 which generates a reference switching signal, according to a PWM method, in a DC-DC converter 8 . Thereby, the timing at data writing every scanning line is in synchronization with the phase of a ripple component superimposed on a driving voltage Va from the DC-DC converter 8 . Accordingly, a problem that there is caused a state in which light-emitting intensity is different every scanning line can be solved because the same voltage Vgs between a gate and a source is supplied every scanning line to a light-emitting driving transistor Tr 2 at any time even if the ripple component by switching of the DC-DC converter is superimposed on the driving voltage Va. Thereby, a problem that the display quality of images is remarkably reduced can be prevented in a light-emitting driving operation of a display panel, wherein the operation has a configuration in which an organic EL element with a light-emitting intensity characteristic of a current dependence type, for example, is used as a pixel.
1. A light-emitting display device provided with a display panel on which multiple pixels including a light-emitting element respectively are arranged at intersecting positions of a plurality of scanning lines and a plurality of data lines, wherein
the display panel is electrically connected to a DC-DC converter, and a switching operation by a switching regulator circuit in the DC-DC converter and an operation for scanning selection of scanning lines on the display panel are in synchronization with each other.
2. The light-emitting display device according to claim 1 , wherein
the frequency of the switching operation by a switching regulator circuit in the DC-DC converter is set at a frequency which is integral multiple of a scanning frequency given to the display panel.
3. The light-emitting display device according to claim 1 , wherein
each pixel arranged on the display panel comprises at least a light-emitting driving transistor connected to the light-emitting element in series in order to drive the light-emitting element for light-emitting.
4. The light-emitting display device according to claim 2 , wherein
each pixel arranged on the display panel comprises at least a light-emitting driving transistor connected to the light-emitting element in series in order to drive the light-emitting element for light-emitting.
5. The light-emitting display device according to claim 3 , wherein
a capacitor for charge conservation which keeps the gate potential of the light-emitting driving transistor is connected to the gate of the light-emitting driving transistor.
6. The light-emitting display device according to claim 4 , wherein
a capacitor for charge conservation which keeps the gate potential of the light-emitting driving transistor is connected to the gate of the light-emitting driving transistor.
7. The light-emitting display device according to claim 1 , wherein the switching operation by a switching regulator circuit in the DC-DC converter and the operation for scanning selection of scanning lines on the display panel are configured to be based on a common clock signal.
8. The light-emitting display device according to claim 7 , wherein
an erasing transistor which can erase charges in the capacitor for charge conservation is further provided for each pixel, and the switching operation in the section of the circuit structure and a starting operation of erasing in the erasing transistor are executed according to a common clock signal.
9. The light-emitting display device according to any one of claims 1 to 6 , wherein
the switching operation by a switching regulator circuit in the DC-DC converter is based on a PWM method.
10. The light-emitting display device according to claim 7 , wherein
the switching operation by a switching regulator circuit in the DC-DC converter is based on a PWM method.
11. The light-emitting display device according to claim 8 , wherein
the switching operation by a switching regulator circuit in the DC-DC converter is based on a PWM method.
12. The light-emitting display device according to claim 9 , wherein
a reference signal which executes a switching operation according to the PWM method is configured to use the output of a voltage control oscillator in a PLL circuit, in which a clock signal executing a scanning selection operation in the display panel is used as an input.
13. The light-emitting display device according to claim 10 , wherein
a reference signal which executes a switching operation according to the PWM method is configured to use the output of a voltage control oscillator in a PLL circuit, in which a clock signal executing a scanning selection operation in the display panel is used as an input.
14. The light-emitting display device according to claim 11 , wherein
a reference signal which executes a switching operation according to the PWM method is configured to use the output of a voltage control oscillator in a PLL circuit, in which a clock signal executing a scanning selection operation in the display panel is used as an input.
15. A driving control method for a light-emitting display device provided with a display panel on which multiple pixels comprising a light-emitting element are arranged at intersecting positions of a plurality of scanning lines and a plurality of data lines, wherein, according to the control of the driving control method,
the display panel is electrically connected to a DC-DC converter, and a switching operation by a switching regulator circuit in the DC-DC converter and an operation for scanning selection of scanning lines on the display panel are in synchronization with each other.