DISPLAY PANEL DEVICE, DISPLAY DEVICE, AND CONTROL METHOD THEREOF

• US 20110141095A1
• Filed: 02/25/2011
• Published: 06/16/2011
• Est. Priority Date: 11/19/2009
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: ONO, Shinya, MATSUI, Masafumi
• Granted Patent: US 8,294,701 B2
• Time in Patent Office: Days
• US Class Current: 345/211
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: G09G 2300/0876 Supplementary capacities in pixels having special driving circuits and electrodes instead of being connected to common electrode or ground; Use of additional capacitively coupled compensation electrodes
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2320/0223 Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

A display panel device includes: a luminescence element; a capacitor including first and second capacitor electrodes; a driver having a gate connected to the first capacitor electrode for allowing a drain current to flow through the luminescence element; a first switch switchably interconnecting a data line and the first capacitor electrode for supplying a signal voltage to the capacitor; a second switch switchably interconnecting a source of the driver and the second capacitor electrode; and a controller. The controller is configured to: turn ON the first switch while the second switch is ON to supply the signal voltage to the first capacitor electrode and flow a current between the source of the driver and the second capacitor electrode; and, after predetermined time period, turn OFF the second switch to cause non-conduction between the source of the driver and the second capacitor electrode.

Claims

1. A display panel device, comprising:

a luminescence element including a first luminescence electrode and a second luminescence electrode;

a first capacitor including a first capacitor electrode and a second capacitor electrode for holding a capacitor voltage;

a driver including a gate electrode, a drain electrode, and a source electrode for driving the luminescence element to produce a luminescence by allowing a drain current corresponding to the capacitor voltage to flow through the luminescence element, the gate electrode being connected to the first capacitor electrode, the source electrode being connected to the first luminescence electrode;

a first power line for determining a potential of the drain electrode of the driver;

a second power line electrically connected to the second luminescence electrode;

a data line for supplying a signal voltage to the first capacitor;

a first switch switchably interconnecting the data line and the first capacitor electrode;

a second switch switchably interconnecting the source electrode of the driver and the second capacitor electrode; and

a controller for controlling the first switch and the second switch,

wherein the controller is configured to;

turn ON the second switch to interconnect the source electrode of the driver and the second capacitor electrode, and, when the second switch is in an ON state, turn ON the first switch to interconnect the data line and the first capacitor electrode to supply the signal voltage to the first capacitor and flow a current between the source electrode of the driver and the second capacitor electrode; and

turn OFF the second switch after an elapse of a predetermined time period after the signal voltage is supplied to the first capacitor to cause non-conduction between the source electrode of the driver and the second capacitor electrode,

whereby a charge accumulated in the first capacitor is discharged when the current flows between the source electrode of the driver and the second capacitor electrode during the predetermined time period.

2. The display panel device according to claim 1, further comprising:

a second capacitor connected to the second capacitor electrode; and

a bias voltage line for supplying, to the second capacitor, a reverse bias voltage which generates, in the first capacitor, a capacitor potential difference that is greater than a driver threshold voltage of the driver,

wherein the controller is further configured to;

turn ON the second switch to interconnect the source electrode of the driver and the second capacitor electrode, and turn ON the first switch to supply the reverse bias voltage to the second capacitor while a fixed voltage for fixing a voltage of the first capacitor electrode is supplied from the data line, the reverse bias voltage generating, in the first capacitor, the capacitor potential difference that is greater than the driver threshold voltage; and

turn ON the first switch while the driver is in an OFF state and the second switch is in the ON state to supply the signal voltage to the first capacitor electrode after the capacitor potential difference reaches the driver threshold voltage and the driver is in the OFF state.

3. The display panel device according to claim 2,

wherein the controller is further configured to:

turn ON the first switch to supply the reverse bias voltage to the second capacitor while the fixed voltage for fixing the voltage of the first capacitor electrode is supplied from the data line, the reverse bias voltage generating, in the first capacitor, the capacitor potential difference that is greater than the driver threshold voltage;

turn OFF the first switch; and

turn ON the first switch while the driver is in the OFF state and the second switch is in the ON state to supply the signal voltage to the first capacitor electrode after the capacitor potential difference reaches the driver threshold voltage and the driver is in the OFF state.

4. The display panel device according to claim 2,

wherein the fixed voltage is set such that, after the capacitor potential difference reaches the driver threshold voltage and the driver is in the OFF state, a luminescence potential difference between the first luminescence electrode and the second luminescence electrode becomes lower than a luminescence threshold voltage of the luminescence element at which the luminescence element produces the luminescence.

5. The display panel device according to claim 1, further comprising:

a third power line for supplying, to the second capacitor electrode, a reference voltage which generates, in the first capacitor, a capacitor potential difference that is greater than a driver threshold voltage of the driver; and

a third switch switchably interconnecting the second capacitor electrode and the third power line,

wherein the controller is further configured to;

turn ON the third switch to interconnect the second capacitor electrode and the third power line to supply the reference voltage to the second capacitor electrode;

turn ON the first switch to supply a fixed voltage for fixing a voltage of the first capacitor electrode from the data line, and

turn ON the first switch while the second switch is in the ON state and the driver is in an OFF state to supply the signal voltage to the first capacitor electrode after the capacitor potential difference reaches the driver threshold voltage and the driver is in the OFF state.

6. The display panel device according to claim 5,

wherein the third power line is a scanning line, and the scanning line is configured to turn ON and turn OFF the first switch, and

the scanning line supplies the reference voltage to turn OFF the first switch.

7. The display panel device according to claim 1,

wherein a first time constant for turning ON and turning OFF the first switch is at least equal to a second time constant for turning ON and turning OFF the second switch.

8. A display device, comprising:

play panel device according to claim 1; and

a power source that supplies power to the first power line and the second power line,

wherein the luminescence element further includes a luminescent layer sandwiched between the first luminescence electrode and the second luminescence electrode, and

a plurality of luminescence elements including the luminescence element is arranged in a matrix pattern.

9. The display device according to claim 8,

wherein the luminescence element is an organic electroluminescence element.

10. A display device, comprising:

play panel device according to claim 1; and

a power source that supplies power to the first power line and the second power line,

wherein the luminescence element further includes a luminescent layer sandwiched between the first luminescence electrode and the second luminescence electrode,

a pixel includes the luminescence element, the first capacitor, the driver, the first switch, and the second switch, and

a plurality of pixels including the pixel are arranged in a matrix pattern.

11. A method of controlling a display device,

wherein the display device includes:

a luminescence element having a first luminescence electrode and a second luminescence electrode;

a first capacitor having a first capacitor electrode and a second capacitor electrode for holding a capacitor voltage;

a driver having a gate electrode, a drain electrode, and a source electrode for driving the luminescence element to produce a luminescence by allowing a drain current corresponding to the capacitor voltage to flow through the luminescence element, the gate electrode being connected to the first capacitor electrode, the source electrode being connected to the first luminescence electrode;

a first power line for determining a potential of the drain electrode of the driver;

a second power line electrically connected to the second luminescence electrode;

a data line for supplying a signal voltage to the first capacitor;

a first switch switchably interconnecting the data line and the first capacitor electrode; and

a second switch switchably interconnecting the source electrode of the driver and the second capacitor electrode, and

the method comprising;

turning ON the second switch to interconnect the source electrode of the driver and the second capacitor electrode, and, when the second switch is in an ON state, turning ON the first switch to interconnect the data line and the first capacitor electrode to supply the signal voltage to the first capacitor and flow a current between the source electrode of the driver and the second capacitor electrode; and

turning OFF the second switch after an elapse of a predetermined time period after the signal voltage is supplied to the first capacitor to cause non-conduction between the source electrode of the driver and the second capacitor electrode,

whereby a charge accumulated in the first capacitor is discharged when the current flows between the source electrode of the driver and the second capacitor electrode during the predetermined time period.