Display device and method of driving the same

1. A display device comprising:

a display unit including a plurality of pixels each having an anode electrode and a cathode electrode;

a power supplying unit configured to supply a high-side potential and a low-side potential to the display unit;

a voltage measuring unit configured to measure an anode potential and a cathode potential of at least one representative pixel which is a predetermined one of the pixels; and

an arithmetic circuit that calculates a voltage drop amount in the at least one representative pixel and feeds back the voltage drop amount to the power supplying unit, the voltage drop amount being an absolute value of a value obtained by subtracting the cathode potential corresponding to the low-side potential from the anode potential corresponding to a preset potential in a positive electrode of the power supplying unit,

wherein the power supplying unit is configured to regulate the high-side potential with respect to the low-side potential, according to at least the anode potential and a potential difference between the low-side potential supplied by the power supplying unit to the display unit and the cathode potential of the at least one representative pixel measured by the voltage measuring unit, and supply the regulated high-side potential to the display unit, and

the power supplying unit is configured to raise the high-side potential with respect to the low-side potential by a greater amount as the voltage drop amount is greater, and supply the raised high-side potential to the display unit.

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

a high-potential monitor wire having one end connected to the at least one representative pixel and an other end connected to the voltage measuring unit, for transmitting the anode potential; and

a low-potential monitor wire having one end connected to the at least one representative pixel and an other end connected to the voltage measuring unit, for transmitting the cathode potential.

3. The display device according to claim 1 , wherein the display unit includes:

two or more representative pixels from which anode potentials are measured, each of the representative pixels being the at least one representative pixel; and

two or more representative pixels from which cathode potentials are measured, each of the representative pixels being the at least representative pixel,

the voltage measuring unit includes:

a smallest value circuit that detects a smallest potential out of two or more anode potentials measured from the two or more representative pixels; and

a largest value circuit that detects a largest potential out of two or more cathode potentials measured from the two or more representative pixels, and

the arithmetic circuit calculates the voltage drop amount, using the smallest potential as the anode potential of the at least one representative pixel and the largest potential as the cathode potential of the at least one representative pixel.

4. The display device according to claim 1 , wherein each of the pixels includes a driving element and a luminescence element,

the driving element includes a source electrode and a drain electrode,

the luminescence element includes a first electrode and a second electrode, the first electrode being connected to one of the source electrode and the drain electrode of the driving element,

the anode potential is applied to one of the second electrode and the other of the source electrode and the drain electrode, and

the cathode potential is applied to the other of the second electrode and the other of the source electrode and the drain electrode.

5. The display device according to claim 4 , wherein the second electrode forms part of a common electrode provided in common to the pixels,

the common electrode is electrically connected to the power supplying unit so that a potential is applied to the common electrode from a periphery of the common electrode, and

the at least one representative pixel is disposed near a center of the display unit.

6. The display device according to claim 5 , wherein the second electrode comprises a transparent conductive material including a metal oxide.

7. The display device according to claim 4 , wherein the luminescence element is an organic electroluminescence (EL) element.

8. A display device comprising:

a display unit including a plurality of pixels each having an anode electrode and a cathode electrode;

a power supplying unit configured to supply a high-side potential and a low-side potential to the display unit;

a voltage measuring unit configured to measure an anode potential and a cathode potential of at least one representative pixel which is a predetermined one of the pixels; and

an arithmetic circuit that calculates and outputs a converted potential which is a value obtained by adding-up the low-side potential and the anode potential and subtracting the cathode potential,

wherein the power supplying unit is configured to regulate the high-side potential with respect to the low-side potential, according to at least the anode potential and a potential difference between the low-side potential supplied by the power supplying unit to the display unit and the cathode potential of the at least one representative pixel measured by the voltage measuring unit, and supply the regulated high-side potential to the display unit, and

the power supplying unit is configured to compare the converted potential outputted from the arithmetic circuit and a preset potential in a positive electrode of the power supplying unit, raise the high-side potential with respect to the low-side potential by a greater amount as the converted potential is lower than the preset potential, and supply the raised high-side potential to the display unit.

9. The display device according to claim 8 , wherein the display unit includes:

two or more representative pixels from which anode potentials are measured, each of the representative pixels being the at least one representative pixel; and

two or more representative pixels from which cathode potentials are measured, each of the representative pixels being the at least one representative pixel,

the voltage measuring unit includes:

a smallest value circuit that detects a smallest potential out of two or more anode potentials measured from the two or more representative pixels; and

a largest value circuit that detects a largest potential out of two or more cathode potentials measured from the two or more representative pixels, and

the arithmetic circuit calculates the converted potential, using the smallest potential as the anode potential of the at least one representative pixel and the largest potential as the cathode potential of the at least one representative pixel.

10. The display device according to claim 8 ,

wherein the display unit includes a plurality of representative pixels from which anode potentials and cathode potentials are measured, each of the representative pixels being the at least one representative pixel,

the display device further comprises a plurality of arithmetic circuits that calculate and output converted potentials for the respective representative pixels, each of the arithmetic circuits being the arithmetic circuit, and

the power supplying unit is configured to compare the preset potential and a smallest converted potential among the converted potentials outputted from the arithmetic circuits, raise the high-side potential with respect to the low-side potential by a greater amount as the smallest converted potential is lower than the preset potential, and output the raised high-side potential to the display unit.

11. A display device driving method for driving a display device including a power supplying unit that supplies a high-side potential and a low-side potential to a display unit including a pixel having an anode electrode and a cathode electrode, the method comprising:

measuring a cathode potential of the pixel; and

causing the power supplying unit to supply, to the display unit, the high-side potential with respect to the low-side potential, according to a potential difference between at least the low-side potential supplied by the power supplying unit to the display unit and the cathode potential measured in the measuring,

wherein the power supplying unit is caused to raise the high-side potential with respect to the low-side potential by a greater amount as an amount of voltage rise occurring in a cathode power source wire increases, and supply the raised high-side potential to the display unit.

12. The display device driving method according to claim 11 , wherein the display unit includes a plurality of pixels each of which is the pixel;

in the measuring, a cathode potential of at least one representative pixel is measured, the at least one representative pixel being a predetermined one of the pixels, and

in the causing, the power supplying unit is caused to supply, to the display unit, the high-side potential with respect to the low-side potential, according to a potential difference between at least the low-side potential supplied by the power supplying unit to the display unit and the cathode potential of the at least one representative pixel measured in the measuring.

13. The display device driving method according to claim 12 , wherein in voltage measuring, an anode potential and the cathode potential of the at least one representative pixel are measured, and

in the causing, the power supplying unit is caused to supply, to the display unit, the high-side potential with respect to the low-side potential, according to the anode potential and the potential difference between the low-side potential and the cathode potential.