Method of driving organic electroluminescent display device

1. A method of driving an organic electroluminescent display device, the method comprising:

determining a luminance value from input data;

adjusting the luminance value by a first method when the luminance value is greater than or equal to a predetermined number of nits;

adjusting the luminance value by a second method when the luminance value is less than the predetermined number of nits; and

generating data to which the first or second method is applied, wherein:

the first method adjusts the luminance value by adjusting light emission time,

the second method adjusts the luminance value based on a light emission time that corresponds to the predetermined number of nits and then decreases the luminance value by a percentage by limiting a current, and

the predetermined number of nits is between 2 nits and 10 nits inclusive.

2. The method as claimed in claim 1 , wherein the first method includes:

supplying the luminance value to a timing controller;

extracting a light emission time value corresponding to the luminance value from a first lookup table; and

controlling a light emission control driver in response to the extracted light emission time value.

3. The method as claimed in claim 2 , wherein the first lookup table includes light emission times that decrease from a first luminance value to a second luminance value less than the first luminance value.

4. The method as claimed in claim 1 , wherein the second method includes:

supplying luminance of the predetermined number of nits to a timing controller;

extracting a light emission time value corresponding to the predetermined number of nits from a first lookup table;

controlling a light emission control driver in response to the extracted light emission time value; and

decreasing the luminance by the percentage by limiting a current.

5. The method as claimed in claim 4 , wherein:

the first lookup table includes light emission times that decrease with decreasing luminance, and

a smallest luminance in the first lookup table corresponds to the predetermined number of nits.

6. The method as claimed in claim 4 , wherein decreasing the luminance by the percentage includes:

determining a luminance compensation value from the luminance determined from the input data;

extracting a degree of automatic current limit corresponding to the compensation value from a third lookup table; and

limiting the current in response to the extracted degree of the automatic current limit.

7. The method as claimed in claim 1 , further comprising:

measuring a luminance difference and color coordinates for the generated data;

extracting an offset value for the luminance difference and color coordinates; and

applying the extracted offset value.

8. The method as claimed in claim 7 , wherein:

the offset value is extracted from a second lookup table, and

the second lookup table includes offset values of red and blue larger than an offset value of green.

9. The method as claimed in claim 7 , wherein applying of the extracted offset value includes:

adjusting a gamma voltage in response to the offset value, and

supplying the adjusted gamma voltage to the gamma voltage applying unit.

10. A method of driving an organic electroluminescent display device, the method comprising:

generating a luminance value from input data;

adjusting the luminance value based on a first method when the luminance value is greater than or equal to 10 nits; and

adjusting the luminance value based on a second method when the luminance value is less than 10 nits, wherein the first method adjusts a light emission time according to the luminance value and the second method adjusts the luminance value based on a light emission time corresponding to the luminance value of 10 nits and then decreases the luminance by a percentage by limiting a current.

11. The method as claimed in claim 10 , wherein the first method includes:

supplying the luminance value to a timing controller;

extracting a light emission time value corresponding to the luminance value from a first lookup table; and

controlling a light emission control driver in response to the extracted light emission time value.

12. The method as claimed in claim 11 , wherein the first lookup table includes light emission times that decrease from a first luminance value to a second luminance value less than the first luminance value.

13. The method as claimed in claim 10 , wherein the second method includes:

supplying the luminance value of 10 nits to a timing controller;

extracting a light emission time value corresponding to 10 nits from a first lookup table;

controlling a light emission control driver in response to the extracted light emission time value; and

decreasing the luminance value by limiting the current.

14. The method as claimed in claim 13 , wherein decreasing of the luminance value includes decreasing ratio of the luminance value based on the following equation: (the luminance value of 10 nits−first generated luminance value)*10%.

15. The method as claimed in claim 14 , wherein decreasing the luminance value includes:

determining a luminance compensation value from the luminance generated from the input data;

extracting a degree of automatic current limit corresponding to the compensation value from a third lookup table; and

limiting the current in response to the extracted degree of the automatic current limit.

16. The method as claimed in claim 10 , further comprising:

measuring a luminance difference and color coordinates for the generated data;

extracting an offset value for the luminance difference and the color coordinates; and

applying the extracted offset value.

17. The method as claimed in claim 16 , wherein:

the offset value is extracted from a second lookup table, and

the second lookup table includes offset values of red and blue larger than an offset value of green.

18. The method as claimed in claim 17 , wherein applying of the extracted offset value includes:

adjusting a gamma voltage in response to the offset value, and

supplying the adjusted gamma voltage to the gamma voltage applying unit.