Organic light emitting display device and method of driving the same
An organic light emitting display device includes pixel unit, a power supply, and a timing controller. The power supply supplies a driving voltage to the pixel unit. The timing controller divides the pixel unit into a plurality of regions, calculates color on-pixel ratio (C-OPR) values of the regions based on image data, and controls the power supply based on the C-OPR values of the regions.
1. An organic light emitting display device, comprising:
a pixel unit including a plurality of pixels;
a power supply to supply a driving voltage to the pixel unit; and
a timing controller to control the power supply, wherein the timing controller is to divide the pixel unit into a plurality of regions, calculate respective color on-pixel ratio (C-OPR) values of the regions based on image data, and control the power supply based on the respective C-OPR values of the regions.
2. The display device as claimed in claim 1 , wherein the timing controller includes:
a C-OPR calculator to calculate the respective C-OPR values of the regions;
a driving voltage selector to compare the respective C-OPR values of the regions and to select a value of the driving voltage based on at least a maximum C-OPR value among the C-OPR values of the regions; and
a voltage control signal generator to generate a voltage control signal corresponding to the selected value of the driving voltage.
3. The display device as claimed in claim 2 , wherein the C-OPR calculator is to operate the image data of the respective regions together with characteristic values of color light emitting materials and gamma values to calculate the respective C-OPR values of the regions.
4. The display device as claimed in claim 2 , wherein the C-OPR calculator is to calculate the respective C-OPR values of the regions based on the following Equation 1:
C
-
OPR
=
∑
n
=
1
T
{
Rc
(
Rn
255
)
γ
}
T
+
∑
n
=
1
T
{
Gc
(
Gn
255
)
γ
}
T
+
∑
n
=
1
T
{
Bc
(
Bn
255
)
γ
}
T
where Rc, Gc, and Bc respectively represent relative ratios of driving currents that flow through red, green, and blue subpixels of a unit pixel that emits white light, Rn, Gn, and Bn respectively represent image data of the red, green, and blue subpixels in each region, γ represents a gamma value applied to a panel, and T represents a resolution of each region.
5. The display device as claimed in claim 4 , wherein the C-OPR calculator is to calculate a final C-OPR value based on a brightness control ratio in addition to the C-OPR values of Equation 1.
6. The display device as claimed in claim 2 , wherein the timing controller includes a first storage area to store the respective C-OPR values of the regions.
7. The display device as claimed in claim 2 , wherein the driving voltage selector is to select the value of the driving voltage based on the maximum C-OPR value among the C-OPR values of the respective regions and at least one of C-OPR values of remaining regions.
8. The display device as claimed in claim 2 , wherein the timing controller includes a second storage area to store the value of the driving voltage in accordance with at least the maximum C-OPR value.
9. The display device as claimed in claim 2 , wherein the timing controller includes a third storage area to store information on the voltage control signal corresponding to the selected value of the driving voltage.
10. The display device as claimed in claim 1 , wherein the power supply is to output the driving voltage having a value corresponding to a voltage control signal input from the timing controller.
11. The display device as claimed in claim 10 , wherein:
the driving voltage includes a high potential power source voltage and a low potential power source voltage, and
the power supply is to control and output a value of the low potential power source voltage based on the voltage control signal.
12. A method for driving an organic light emitting display device, the method comprising:
dividing a pixel unit into a plurality of regions;
receiving image data for the regions;
calculating respective color on-pixel ratio (C-OPR) values for the regions based on the image data of the regions;
comparing the respective C-OPR values of the regions and selecting a value of a driving voltage based on a result of the comparison;
generating a voltage control signal corresponding to the value of the driving voltage;
generating the driving voltage having the voltage value corresponding to the voltage control signal; and
supplying the driving voltage to the pixel unit.
13. The method as claimed in claim 12 , wherein dividing the pixel unit into the plurality of regions includes dividing the pixel unit into the plurality of regions based on a degree of voltage drop of the driving voltage generated in the pixel unit.
14. The method as claimed in claim 12 , wherein calculating the respective C-OPR values of the regions based on the image data of the regions includes operating the image data of the regions together with characteristic values of color light emitting materials and gamma values to calculate the respective C-OPR values of the regions.
15. The method as claimed in claim 14 , wherein calculating the respective C-OPR values of the regions based on the image data of the regions includes calculating a final C-OPR value additionally based on a brightness control ratio corresponding to a brightness change register value that is to entirely control brightness of the pixel unit.
16. The method as claimed in claim 12 , wherein comparing the respective C-OPR values of the regions and selecting the value of the driving voltage based on the comparison result includes selecting a maximum C-OPR value among the respective C-OPR values of the regions and selecting the value of the driving voltage based on at least the maximum C-OPR value.
17. The method as claimed in claim 16 , wherein comparing the respective C-OPR values of the regions and selecting the value of the driving voltage based on the comparison result includes:
selecting at least one of C-OPR values of remaining regions excluding the maximum C-OPR value as a secondary C-OPR value, wherein the value of the driving voltage is selected based on the maximum C-OPR value and the secondary C-OPR value.
18. A controller, comprising:
a calculator to calculate color on-pixel ratio (C-OPR) values of different regions of a display device based on image data; and
logic to control a power supply of the display device based on the C-OPR values of the regions of the display device.
19. The controller as claimed in claim 18 , wherein the calculator includes:
a C-OPR calculator to calculate the C-OPR values of the regions;
a driving voltage selector to compare the C-OPR values and to select a value of a driving voltage based on at least a maximum C-OPR value among the C-OPR values; and
a signal generator to generate a voltage control signal corresponding to the selected value of the driving voltage.
20. The controller as claimed in claim 19 , wherein the C-OPR calculator is to operate the image data of the regions together with characteristic values of color light emitting materials and gamma values to calculate the C-OPR values of the regions.