Display device performing multi-frequency driving

1. A display device comprising:

a display panel including a plurality of pixels;

a data driver configured to provide data signals to the plurality of pixels;

a scan driver configured to provide scan signals to the plurality of pixels based on a scan driver input signal including a scan start signal and a scan clock signal; and

a controller configured to control the data driver and the scan driver, the controller including:

a zone splitting block configured to divide input image data into a plurality of partial image data respectively corresponding to a plurality of partial panel zones of the display panel;

a plurality of panel zone frequency deciding blocks configured to determine a plurality of driving frequencies for the plurality of partial panel zones by analyzing the plurality of partial image data, respectively;

a non-driving period setting block configured to classify a plurality of frame periods into a driving frame period and a non-driving frame period based on a maximum driving frequency of the plurality of driving frequencies; and

a scan driver control block configured to provide the scan driver input signal to the scan driver in the driving frame period, and to not provide the scan start signal and the scan clock signal to the scan driver in the non-driving frame period.

2. The display device of claim 1 , wherein the controller further includes a power block configured to generate a high gate voltage and a low gate voltage,

wherein the scan driver control block includes:

a scan driver input signal generating unit configured to generate an initial scan start signal and an initial scan clock signal; and

a level shifting unit configured to generate, as the scan driver input signal, the scan start signal and the scan clock signal by changing voltage levels of the initial scan start signal and the initial scan clock signal based on at least one of the high gate voltage and the low gate voltage, and

wherein, in the non-driving frame period, the power block is configured to change the at least one of the high gate voltage and the low gate voltage to an off level.

3. The display device of claim 1 , wherein the scan driver control block is configured to provide a scan output masking signal to the scan driver in a partial period of the driving frame period assigned to a portion of the plurality of partial panel zones such that the scan signals are not provided to the portion of the plurality of partial panel zones within the driving frame period.

4. The display device of claim 3 , wherein the scan driver includes:

a plurality of stages configured to generate the scan signals for a plurality of scan lines included in the display panel; and

a plurality of logic gates respectively connected to the plurality of stages, and configured to selectively output the scan signals generated by the plurality of stages in response to the scan output masking signal, respectively.

5. The display device of claim 1 , wherein the display device is a foldable display device,

wherein the plurality of partial panel zones include a first partial panel zone located in a first direction from a folding line of the foldable display device, and a second partial panel zone located in a second direction opposite to the first direction from the folding line, and

wherein the zone splitting block is configured to divide the input image data into, as the plurality of partial image data, first partial image data for the first partial panel zone and second partial image data for the second partial panel zone.

6. The display device of claim 1 , wherein each of the plurality of panel zone frequency deciding blocks includes:

a still image detecting unit configured to receive corresponding partial image data of the plurality of partial image data at an input frame frequency, and to determine whether the corresponding partial image data represent a still image; and

a driving frequency deciding unit configured to determine a corresponding driving frequency of the plurality of driving frequencies as the input frame frequency when the corresponding partial image data do not represent the still image, and to determine the corresponding driving frequency as a frequency lower than the input frame frequency when the corresponding partial image data represent the still image.

7. The display device of claim 6 , wherein each of the plurality of panel zone frequency deciding blocks further includes:

a representative value memory configured to store a representative value of the corresponding partial image data in a previous frame period, and

wherein the still image detecting unit is configured to calculate a representative value of the corresponding partial image data in a current frame period, and to determine whether or not the corresponding partial image data represents the still image by comparing the calculated representative value of the corresponding partial image data with the representative value of the corresponding partial image data stored in the representative value memory.

8. The display device of claim 6 , wherein each of the plurality of panel zone frequency deciding blocks further includes:

a flicker lookup table configured to store flicker values corresponding to respective image data gray levels, and

wherein the driving frequency deciding unit is configured to determine, based on the corresponding partial image data representing the still image, a flicker value corresponding to a gray level of the corresponding partial image data by using the flicker lookup table, and to determine the corresponding driving frequency according to the determined flicker value.

9. The display device of claim 6 , wherein each of the plurality of panel zone frequency deciding blocks further includes:

a driving frequency mixing unit configured to gradually change a corresponding one of the plurality of driving frequencies for a corresponding partial panel zone of the plurality of partial panel zones from a previous driving frequency for the partial panel zone to the corresponding driving frequency determined by the driving frequency deciding unit when the corresponding driving frequency determined by the driving frequency deciding unit is changed from the previous driving frequency.

10. The display device of claim 1 , wherein each of the plurality of pixels includes:

a driving transistor configured to generate a driving current;

a switching transistor configured to transfer a corresponding one of the data signals to a source of the driving transistor;

a compensating transistor configured to diode-connect the driving transistor;

a storage capacitor configured to store the corresponding one of the data signals transferred through the switching transistor and the diode-connected driving transistor;

a first initializing transistor configured to provide an initialization voltage to the storage capacitor and a gate of the driving transistor;

a first emission controlling transistor configured to connect a line of a power supply voltage to the source of the driving transistor;

a second emission controlling transistor configured to connect a drain of the driving transistor to an organic light emitting diode;

a second initializing transistor configured to provide the initialization voltage to the organic light emitting diode; and

the organic light emitting diode configured to emit light based on the driving current,

wherein at least a first one of the driving transistor, the switching transistor, the compensating transistor, the first initializing transistor, the first emission controlling transistor, the second emission controlling transistor, or the second initializing transistor is implemented with a PMOS transistor, and at least a second one of the driving transistor, the switching transistor, the compensating transistor, the first initializing transistor, the first emission controlling transistor, the second emission controlling transistor, or the second initializing transistor is implemented with an NMOS transistor.

11. The display device of claim 1 , wherein the non-driving period setting block is configured to set a partial period of the driving frame period as a non-driving partial frame period based on a driving frequency lower than the maximum driving frequency among the plurality of driving frequencies, and

wherein the scan driver control block is configured to not provide the scan driver input signal to the scan driver in the non-driving frame period and the non-driving partial frame period.

12. The display device of claim 11 , wherein the controller further includes a power block configured to generate a high gate voltage and a low gate voltage,

wherein the scan driver control block includes:

a scan driver input signal generating unit configured to generate an initial scan start signal and an initial scan clock signal; and

a level shifting unit configured to generate, as the scan driver input signal, the scan start signal and the scan clock signal by changing voltage levels of the initial scan start signal and the initial scan clock signal based on at least one of the high gate voltage and the low gate voltage, and

wherein the power block is configured to, in the non-driving frame period and the non-driving partial frame period, change the at least one of the high gate voltage and the low gate voltage to an off level.

13. A display device comprising:

a display panel including a plurality of pixels;

a data driver configured to provide data signals to the plurality of pixels;

a scan driver configured to provide scan signals to the plurality of pixels based on a scan driver input signal including a scan start signal and a scan clock signal; and

a controller configured to control the data driver and the scan driver, the controller including:

a zone splitting and still image detecting block configured to receive input image data at an input frame frequency, and configured to divide the input image data into moving image partial data representing a moving image and still image partial data representing a still image;

a zone splitting and panel zone frequency deciding block configured to determine a first driving frequency for a first partial panel zone of the display panel corresponding to the moving image partial data as the input frame frequency, and to determine a plurality of second driving frequencies for a plurality of second partial panel zones of the display panel by analyzing the still image partial data;

a non-driving period setting block configured to classify a plurality of frame periods into a driving frame period and a non-driving frame period based on a maximum driving frequency of the first driving frequency and the plurality of second driving frequencies; and

a scan driver control block configured to provide the scan driver input signal to the scan driver in the driving frame period, and to not provide the scan start signal and the scan clock signal to the scan driver in the non-driving frame period.

14. The display device of claim 13 , wherein the controller further includes a power block configured to generate a high gate voltage and a low gate voltage,

wherein the scan driver control block includes:

a scan driver input signal generating unit configured to generate an initial scan start signal and an initial scan clock signal; and

a level shifting unit configured to generate, as the scan driver input signal, the scan start signal and the scan clock signal by changing voltage levels of the initial scan start signal and the initial scan clock signal based on at least one of the high gate voltage and the low gate voltage, and

wherein the power block is configured to, in the non-driving frame period, change the at least one of the high gate voltage and the low gate voltage to an off level.

15. The display device of claim 13 , wherein the zone splitting and still image detecting block includes:

a plurality of representative value memories configured to store a plurality of representative values of a plurality of input partial image data in a previous frame period; and

a zone still image detecting unit configured to:

receive the input image data in a current frame period;

divide the input image data in the current frame period into the plurality of input partial image data;

calculate a plurality of representative values of the plurality of input partial image data in the current frame period;

determine whether each of the plurality of input partial image data represent the moving image or the still image by comparing the plurality of representative values with the plurality of representative values stored in the plurality of representative value memories;

output input partial image data representing the moving image among the plurality of input partial image data as the moving image partial data; and

output input partial image data representing the still image among the plurality of input partial image data as the still image partial data.

16. The display device of claim 13 , wherein the zone splitting and panel zone frequency deciding block includes:

a flicker lookup table configured to store flicker values corresponding to respective image data gray levels; and

a zone driving frequency deciding unit configured to:

determine the first driving frequency for the first partial panel zone corresponding to the moving image partial data as the input frame frequency;

divide the still image partial data into a plurality of segment data for a plurality of segments;

determine a plurality of segment flicker values corresponding to gray levels of the plurality of segment data by using the flicker lookup table;

determine the plurality of second partial panel zones by grouping the plurality of segments based on a plurality of segment driving frequencies corresponding to the plurality of segment flicker values; and

respectively determine the plurality of second driving frequencies for the plurality of second partial panel zones based on the plurality of segment driving frequencies of the plurality of second partial panel zones.

17. The display device of claim 13 , wherein the non-driving period setting block sets a partial period of the driving frame period as a non-driving partial frame period based on a driving frequency lower than the maximum driving frequency among the first driving frequency and the plurality of second driving frequencies, and

wherein the scan driver control block does not provide the scan driver input signal to the scan driver in the non-driving frame period and the non-driving partial frame period.

18. The display device of claim 17 , wherein the controller further includes a power block configured to generate a high gate voltage and a low gate voltage,

wherein the scan driver control block includes:

a scan driver input signal generating unit configured to generate an initial scan start signal and an initial scan clock signal; and

a level shifting unit configured to generate, as the scan driver input signal, the scan start signal and the scan clock signal by changing voltage levels of the initial scan start signal and the initial scan clock signal based on at least one of the high gate voltage and the low gate voltage, and

wherein the power block is configured to, in the non-driving frame period and the non-driving partial frame period, change the at least one of the high gate voltage and the low gate voltage to an off level.