Image display apparatus and driving method thereof, and image display apparatus assembly and driving method thereof
View Patent ↗An image display apparatus includes: an image display panel having a two-dimensional matrix with (P×Q) pixels each including first, second and third sub-pixels for displaying respective first, second and third elementary colors, and fourth sub-pixel for displaying a fourth color; and a signal processing section configured to receive first, second and third sub-pixel input signals respectively provided with signal values of x 1-(p, q) , x 2-(p, q) and x 3-(p, q) , and to output first, second, third and fourth sub-pixel output signals respectively provided with signal values of X 1-(p, q) , X 2-(p, q) , X 3-(p, q) and X 4-(p, q) , which used for determining the display gradations of the first, second, third, and fourth sub-pixels, respectively, with regard to a (p, q)th pixel where notations p and q are integers satisfying equations 1≦p≦P and 1≦q≦Q.
1. An image display apparatus comprising:
(A) an image display panel having a two-dimensional matrix with (P×Q) pixels each including a first sub-pixel for displaying a first elementary color, a second sub-pixel for displaying a second elementary color, a third sub-pixel for displaying a third elementary color and a fourth sub-pixel for displaying a fourth color; and
(B) a signal processing section configured to receive
a first sub-pixel input signal,
a second sub-pixel input signal and
a third sub-pixel input signal, and to output
a first sub-pixel output signal used for determining the display gradation of said first sub-pixel,
a second sub-pixel output signal used for determining the display gradation of said second sub-pixel,
a third sub-pixel output signal used for determining the display gradation of said third sub-pixel as well as
a fourth sub-pixel output signal used for determining the display gradation of said fourth sub-pixel, and
said signal processing section carries out the following processes of
finding a saturation S and said lightness value V(S) for each of a plurality of pixels on the basis of the signal values of sub-pixel input signals in said pixels, and
finding an extension coefficient α 0 on the basis of at least one of ratios V max (S)/V(S) found in said pixels.
2. The image display apparatus according to claim 1 wherein said signal processing section is capable of finding output signal values X 1-(p, q) , X 2-(p, q) and X 3-(p, q) on the basis of the following equations:
X 1-(p,q) =α 0 ·x 1-(p,q) −χ·X 4-(p,q) ;
X 2-(p,q) =α 0 ·x 2-(p,q) −χ·X 4-(p,q) ; and
X 3-(p,q) =α 0 ·x 3-(p,q) −χ·X 4-(p,q) ;
where, in said above equations, reference notation x denotes a constant dependent on said image display apparatus whereas reference notations X 1-(P, q) , X 2-(p,q) and X 3-(p, q) each denote an output signal value in said (p, q)th pixel.
3. The image display apparatus according to claim 2 wherein said constant χ is expressed by the following equation:
χ= BN 4 /BN 1-3
where, in said above equation, reference notation BN 1-3 denotes the luminance of a set of first, second and third sub-pixels for a case in which
a signal having a value corresponding to the maximum signal value of said first sub-pixel output signal is supplied to said first sub-pixel,
a signal having a value corresponding to the maximum signal value of said second sub-pixel output signal is supplied to said second sub-pixel, and
a signal having a value corresponding to the maximum signal value of said third sub-pixel output signal is supplied to said third sub-pixel
whereas reference notation BN 4 denotes the luminance of said fourth sub-pixel for a case in which a signal having a value corresponding to the maximum signal value of said fourth sub-pixel output signal is supplied to said fourth sub-pixel.
4. The image display apparatus according to claim 1 wherein a saturation S (p, q) and a lightness value V (p, q) in said HSV color space in a (p, q)th pixel are found on the basis of the following equations:
S (p,q) =(Max (p,q) −Min (p,q) )/Max (p,q) ; and
V (p,q) =Max (p,q) ,
where, in said above equations,
notation Max(p, q) denotes the maximum value of the signal values of said three sub-pixel input signals x 1-(p,q) , x 2-(p, q) and x 3-(p, q) ,
notation Min(p, q) denotes the minimum value of the signal values of said three sub-pixel input signals x 1-(p, q) , x 2-(p, q) and x 3-(p, q) ,
said saturation S can have a value in the range 0 to 1 and said lightness value V can have a value in said range 0 to (2 n −1) whereas notation n in the expression (2 n −1) is an integer representing the number of display gradation bits.
5. The image display apparatus according to claim 4 wherein said output signal value X 4-(p, q) is determined on the basis of said minimum value Min (p, q) and said extension coefficient α 0 .
6. The image display apparatus according to claim 1 wherein the smallest value among the values of said ratios V max (S)/V(S) found in said pixels is taken as said extension coefficient α 0 .
7. The image display apparatus according to claim 1 wherein said fourth color is the white color.
8. The image display apparatus according to claim 1
wherein said image display apparatus is a color liquid-crystal display apparatus which includes
a first color filter placed between said first sub-pixel and the image observer to serve as a filter for passing light of said first elementary color,
a second color filter placed between said second sub-pixel and said image observer to serve as a filter for passing light of said second elementary color, and
a third color filter placed between said third sub-pixel and said image observer to serve as a filter for passing light of said third elementary color.
9. The image display apparatus according to claim 1 wherein all (P×Q) pixels are taken as a plurality of pixels for each of which said saturation S and said lightness value V(S) are to be found.
10. The image display apparatus according to claim 1 wherein (P/P 0 ×Q/Q 0 ) pixels are taken as a plurality of pixels for each of which said saturation S and said lightness value V(S) are to be found where notations P 0 and Q 0 represent values satisfying equations P≧P 0 and Q≧Q 0 whereas at least one of ratios P/P 0 and Q/Q 0 are integers each equal to or greater than 2.
11. The image display apparatus according to claim 1 wherein said extension coefficient α 0 is determined for every image display frame.
12. An image display apparatus comprising:
a first image display panel having a two-dimensional matrix with (P×Q) first sub-pixels each used for displaying a first elementary color;
a second image display panel having a two-dimensional matrix with (P×Q) second sub-pixels each used for displaying a second elementary color;
a third image display panel having a two-dimensional matrix with (P×Q) third sub-pixels each used for displaying a third elementary color;
a fourth image display panel having a two-dimensional matrix with (P×Q) fourth sub-pixels each used for displaying a fourth color; and
synthesis means for synthesizing images output by said first, second, third and fourth image display panels,
wherein a maximum lightness value V max (S) expressed as a function of variable saturation S in an HSV color space enlarged by adding said fourth color is stored in said signal processing section, and
said signal processing section carries out the following processes of
finding said saturation S and said lightness value V(S) for each of a plurality of sets each having said first, second and third sub-pixels on the basis of the signal values of sub-pixel input signals in said sets each having said first, second and third sub-pixels,
finding an extension coefficient α 0 on the basis of at least one of ratios V max (S)/V(S) found in said sets each having said first, second and third sub-pixels.
13. An image display apparatus adopting a field sequential system, comprising:
(A) an image display panel having a two-dimensional matrix with (P×Q) pixels; and
(B) a signal processing section configured to receive
a first input signal provided with a signal value of x 1-(p, q) ,
a second input signal provided with a signal value of x 2-(p, q) and
a third input signal provided with a signal value of x 3-(p, q) , and to output
a first output signal provided with a signal value of X 1-(p, q) and used for determining the display gradation of a first elementary color,
a second output signal provided with a signal value of X 2-(p, q) and used for determining the display gradation of a second elementary color,
a third output signal provided with a signal value of X 3-(p, q) and used for determining the display gradation of a third elementary color as well as
a fourth output signal provided with a signal value of X 4-(p, q) and used for determining the display gradation of a fourth color
with regard to a (p, q)th pixel where notations p and q are integers satisfying said equations 1≦p≦P and 1≦q≦Q,
wherein a maximum lightness value V max (S) expressed as a function of variable saturation S in an HSV color space enlarged by adding said fourth color is stored in said signal processing section, and
said signal processing section carries out the following processes of
finding said saturation S and said lightness value V(S) for each of a plurality of pixels on the basis of the signal values of first, second and third input signals in said pixels,
finding an extension coefficient α 0 on the basis of at least one of ratios V max (S)/V(S) found in said pixels.