Display apparatus and display apparatus driving method

1. A display apparatus comprising:

a display panel that includes display elements having a current-driven light-emitting portion, in which the display elements are arranged in a two-dimensional matrix in a first direction and a second direction, and that displays an image on the basis of a video signal; and

a luminance correcting unit that corrects the luminance of the display elements when displaying an image on the display panel by correcting a gradation value of an input signal and outputting the corrected input signal as the video signal,

wherein the luminance correcting unit includes

a reference operating time calculator that calculates the value of a reference operating time in which an temporal variation in black-level gradation of each display element when the corresponding display element operates for a predetermined unit time on the basis of the video signal is equal to an temporal variation in black-level gradation of each display element when it is assumed that the corresponding display element operates on the basis of the video signal of a predetermined reference gradation value,

an accumulated reference operating time storage that stores an accumulated reference operating time value obtained by accumulating the value of the reference operating time calculated by the reference operating time calculator for each display element,

a reference curve storage that stores a reference curve representing the relationship between the operating time of each display element and the temporal variation in black-level gradation of the corresponding display element when the corresponding display element operates on the basis of the video signal of the predetermined reference gradation value,

a black-level shift amount holder that calculates a black-level shift amount used to compensate for the temporal variation in black-level gradation of each display element with reference to the accumulated reference operating time storage and the reference curve storage and that stores the black-level shift amount corresponding to the respective display elements, and

a video signal generator that corrects the gradation value of the input signal corresponding to the respective display elements on the basis of the black-level shift amount stored in the black-level shift amount holder and that outputs the corrected input signal as the video signal.

2. The display apparatus according to claim 1 ,

wherein the luminance correcting unit further includes an operating time conversion factor storage that stores as an operating time conversion factor table the ratio of an temporal variation rate in black-level gradation of each display element when the corresponding display element operates on the basis of the video signal of the gradation values and an temporal variation rate in black-level gradation of each display element when the corresponding display element operates on the basis of the video signal of the predetermined reference gradation value, and

wherein the reference operating time calculator calculates the value of the operating time conversion factor corresponding to the gradation value of the video signal with reference to the operating time conversion factor table stored in the operating time conversion factor storage and calculates the value of the reference operating time by multiplying the value of a unit time by the value of the operating time conversion factor.

3. The display apparatus according to claim 2 , wherein the operating time conversion factor storage stores a plurality of operating time conversion factor tables corresponding to respective ranges of the temporal variation in black-level gradation of the display elements, and

wherein the reference operating time calculator selects and refers to the operating time conversion factor table corresponding to the value of the black-level shift amount stored in the black-level shift amount holder.

4. The display apparatus according to claim 3 , wherein the light-emitting portion is formed of an organic electroluminescence light-emitting portion.

5. A display apparatus driving method using a display apparatus having a display panel that includes display elements having a current-driven light-emitting portion, in which the display elements are arranged in a two-dimensional matrix in a first direction and a second direction, and that displays an image on the basis of a video signal and a luminance correcting unit that corrects the luminance of the display elements when displaying an image on the display panel by correcting a gradation value of an input signal and outputting the corrected input signal as the video signal,

the display apparatus driving method comprising:

correcting the luminance of the display elements when displaying an image on the display panel by correcting a gradation value of an input signal on the basis of the operation of the luminance correcting unit and outputting the corrected input signal as the video signal,

wherein the correcting includes

calculating the value of a reference operating time in which an temporal variation in black-level gradation of each display element when the corresponding display element operates for a predetermined unit time on the basis of the video signal is equal to an temporal variation in black-level gradation of each display element when it is assumed that the corresponding display element operates on the basis of the video signal of a predetermined reference gradation value,

storing an accumulated reference operating time value obtained by accumulating the value of the reference operating time for each display element,

calculating a black-level shift amount used to compensate for the temporal variation in black-level gradation of each display element with reference to the accumulated reference operating time value and a reference curve representing the relationship between the operating time of each display element and the temporal variation in black-level gradation of the corresponding display element when the corresponding display element operates on the basis of the video signal of the predetermined reference gradation value and storing the black-level shift amount corresponding to the respective display elements, and

correcting the gradation value of the input signal corresponding to the respective display elements on the basis of the black-level shift amount and outputting the corrected input signal as the video signal.

6. A display apparatus driving method comprising:

correcting the luminance of the display elements when displaying an image on the display panel by correcting a gradation value of an input signal and outputting the corrected input signal as the video signal,

wherein the correcting includes

calculating the value of a reference operating time in which an temporal variation in black-level gradation of each display element in a video signal during operation is equal to an temporal variation in black-level gradation of each display element in a video signal of a predetermined reference gradation value,

storing an accumulated reference operating time value obtained by accumulating the value of the reference operating time for each display element,

calculating a black-level shift amount with reference to a reference curve representing the relationship between the operating time of each display element and the temporal variation in black-level gradation of the corresponding display element when the corresponding display element operates on the basis of the video signal of the predetermined reference gradation value on the basis of the accumulated reference operating time value and storing the black-level shift amount corresponding to the respective display elements, and

correcting the gradation value of an input signal on the basis of the black-level shift amount.