Display device and degradation compensating method thereof
A display device includes a display part, a degradation compensator that generates a first compensated grayscale value by compensating for a first grayscale value corresponding to a first pixel, and generates a second compensated grayscale value by compensating for a second grayscale value corresponding to a second pixel, and a data driver that generates a first data signal based on the first compensated grayscale value to supply the first data signal to the first pixel, and generates a second data signal based on the second compensated grayscale value to supply the second data signal to the second pixel. A second degradation curve is defined by a first degradation coefficient corresponding to a first degradation curve, and a second degradation coefficient corresponding to a first estimated degradation curve for the light conversion particles of a second color calculated by applying the first degradation curve.
1. A display device comprising:
a display part including:
a first pixel including a light emitting element of a first color; and
a second pixel including:
another light emitting element of the first color; and
light conversion particles of a second color that change the first color to the second color;
a degradation compensator that generates a first compensated grayscale value by compensating for a first grayscale value corresponding to the first pixel based on a first degradation curve defining an estimated luminance according to an accumulated use time of the first pixel, and generates a second compensated grayscale value by compensating for a second grayscale value corresponding to the second pixel based on a second degradation curve defining an estimated luminance that is decreased by the degradation of the light conversion particles of the second pixel according to an accumulated use time of the second pixel; and
a data driver that generates a first data signal based on the first compensated grayscale value and supplies the first data signal to the first pixel, and generates a second data signal based on the second compensated grayscale value and supplies the second data signal to the second pixel, wherein
the second degradation curve of the second pixel is defined by a first degradation coefficient corresponding to the first degradation curve, and a second degradation coefficient corresponding to a first estimated degradation curve for the light conversion particles of the second color calculated by applying the first degradation curve
wherein
the first degradation curve is defined by Equation 1:
L
1
=
exp
[
-
(
t
1
τ
1
)
β
1
]
[
Equation
1
]
wherein L 1 is the estimated luminance according to the accumulated use time of the first pixel, t 1 is the accumulated use time of the first pixel, and τ 1 and β 1 are the first degradation coefficients determined by an initial degradation curve of the first pixel detected in a degradation evaluation of the first pixel, and
wherein
the second degradation curve is defined by Equation 2:
L
2
′
=
exp
[
-
(
t
2
τ
1
)
β
1
-
(
t
2
τ
q
1
)
β
q
1
]
[
Equation
2
]
wherein L 2 ′ is the estimated luminance according to the accumulated use time of the second pixel, t 2 is the accumulated use time of the second pixel, and τ q1 and β q1 are the second degradation coefficients determined by the initial degradation curve of the first pixel and an initial degradation curve of the second pixel detected in a degradation evaluation of the second pixel.
2. The display device of claim 1 , wherein
the first estimated degradation curve is a degradation curve generated according to a ratio of a normalized luminance value of the initial degradation curve of the first pixel to a normalized luminance value of the initial degradation curve of the second pixel, and
the second degradation coefficient is a degradation constant determined by the first estimated degradation curve.
3. The display device of claim 1 , wherein the display part includes a third pixel including another light emitting element of the first color and light conversion particles of a third color that change the first color to the third color.
4. The display device of claim 3 , wherein
the degradation compensator generates a third compensated grayscale value by compensating for a third grayscale value corresponding to the third pixel based on a third degradation curve defining an estimated luminance according to an accumulated use time of the third pixel, and
the data driver generates a third data signal based on the third compensated grayscale value and supplies the third data signal to the third pixel.
5. The display device of claim 4 , wherein the third degradation curve is defined by the first degradation coefficient, and a third degradation coefficient corresponding to a second estimated degradation curve for the light conversion particles of the third color calculated by applying the first degradation curve.
6. The display device of claim 5 , wherein
the third degradation curve is defined by Equation 3:
L
3
′
=
exp
[
-
(
t
3
τ
1
)
β
1
-
(
t
3
τ
q
2
)
β
q
2
]
[
Equation
3
]
wherein L 3 ′ is the estimated luminance according to the accumulated use time of the third pixel, t 3 is the accumulated use time of the third pixel, and τ q2 and β q2 are the third degradation coefficients determined by the initial degradation curve of the first pixel and an initial degradation curve of the third pixel detected in a degradation evaluation of the third pixel.
7. The display device of claim 6 , wherein
the second estimated degradation curve is a degradation curve generated according to a ratio of a normalized luminance value of the initial degradation curve of the first pixel to a normalized luminance value of the initial degradation curve of the third pixel, and
the third degradation coefficient is a degradation constant determined by the second estimated degradation curve.
8. The display device of claim 1 , wherein
the first pixel emits light of the first color, and
the second pixel emits light of the second color.
9. The display device of claim 1 , wherein
each of the first pixel and the second pixel includes at least one blue light emitting element, and
the light conversion particles of the second color are red quantum dots or green quantum dots.
10. The display device of claim 1 , wherein the accumulated use time of the second pixel is generated by an accumulator in response to receiving at least a portion of compensated grayscale value output from the degradation compensator.
11. The display device of claim 1 , wherein the second degradation coefficients are stored in a memory of the degradation compensator.
12. A degradation compensating method of a display device comprising;
detecting degradation characteristics of a first pixel and a second pixel to detect a first initial degradation curve for the first pixel and a second initial degradation curve for the second pixel, the second pixel having an accelerated degradation when the second pixel has one or more light conversion particles disposed over a light emitting element of the second pixel;
modeling a first degradation curve for the first pixel by the first initial degradation curve;
detecting a first degradation coefficient based on the first initial degradation curve;
detecting a second degradation coefficient based on the first initial degradation curve and the second initial degradation curve;
generating, using a degradation compensator, a first compensated grayscale value by compensating for a first grayscale value of the first pixel by applying the first degradation coefficient, and generating, using the degradation compensator, a second compensated grayscale value by compensating for a second grayscale value of the second pixel by applying the first degradation coefficient and the second degradation coefficient;
defining a second degradation curve according to the accumulated use time of the second pixel based on the first degradation coefficient and the second degradation coefficient;
generating a first data signal corresponding to the first compensated grayscale value, and generating a second data signal corresponding to the second compensated grayscale value; and
supplying the first data signal to the first pixel, and supplying the second data signal to the second pixel
the first degradation curve is defined by Equation 1:
L
1
=
exp
[
-
(
t
1
τ
1
)
β
1
]
[
Equation
1
]
wherein L 1 is an estimated luminance according to an accumulated use time of the first pixel, t 1 is the accumulated use time of the first pixel, and τ 1 and β 1 are the first degradation coefficients determined by the first initial degradation curve
wherein the detecting of the second degradation coefficient includes:
calculating a ratio of a first luminance and a second luminance to calculate a first estimated degradation curve, the first luminance being the estimated luminance according to the accumulated use time of the first pixel according to the first initial degradation curve, and the second luminance being an estimated luminance according to an accumulated use time of the second pixel according to the second initial degradation curve; and
detecting the second degradation coefficient based on the first estimated degradation curve, and
wherein
the second degradation curve is defined by Equation 2:
L
2
′
=
exp
[
-
(
t
2
τ
1
)
β
1
-
(
t
2
τ
q
1
)
β
q
1
]
[
Equation
2
]
wherein L 2 ′ is the estimated luminance according to the accumulated use time of the second pixel, t 2 is the accumulated use time of the second pixel, and τ q1 and β q1 are the second degradation coefficients determined by the first initial degradation curve and the second initial degradation curve.