This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2018-050128, filed Mar. 16, 2018, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a display device in which subpixels of multiple primary colors are arranged and a display method of the same.
In conventional display devices, one pixel includes three primary color subpixels representing red, green, and blue, and color display is achieved by controlling the brightness of each subpixel. However, a range of color reproduction is limited in the display with subpixels of three primary colors. Thus, proposed is a display device with more green primary colors in which four primary color subpixels of R, G1, B, R, G2, and B are arranged in the horizontal direction.
However, in the above arrangement of four primary color subpixels, two subpixels of G1 and G2 are used at the same time when white is displayed, and thus, the resolution is lost to a certain extent.
The present application relates generally to a display device in which subpixels of multiple primary colors are arranged and a display method of the same.
According to one embodiment, a display device includes a display panel and a conversion circuit. The display panel is with a first pixel including subpixels of red, first green which is tinged red as compared to a reference green, and blue, and a second pixel including subpixels of red, second green which is tinged blue as compared to the reference green, and blue, where the first pixel and the second pixel are arranged alternately. The conversion circuit is configured to generate a four primary color image of red, first green, second green, and blue from a three primary color image of red, reference green, and blue and to perform rendering the first image and the second image from the four primary color image.
In general, according to one embodiment, a display device includes a display panel and a conversion circuit. The display panel is with a first pixel including subpixels of red, first green which is tinged red as compared to a reference green, and blue, and a second pixel including subpixels of red, second green which is tinged blue as compared to the reference green, and blue, where the first pixel and the second pixel are arranged alternately. The conversion circuit is configured to generate a four primary color image of red, first green, second green, and blue from a three primary color image of red, reference green, and blue and to perform rendering the first image and the second image from the four primary color image. The conversion circuit prioritizes turning on of the first green in the first pixel and turning on of the second green in the second pixel and adjusts a color temperature of white with red and blue during white displaying of a pixel.
With the above structure, vertical, horizontal, and diagonal lines of single-color are displayed as a straight line, and thus, the range of color reproduction is increased, and the resolution can be increased as well.
Various embodiments will be described hereinafter with reference to the accompanying drawings.
Note that, the disclosure is an example, and the contents of the following description do not limit the scope of the invention. Variations which will easily be conceivable by a person having ordinary skill in the art are naturally encompassed within the scope of the invention. In the figures, dimensions of components may be depicted schematically as compared to actual models of the invention for easier understanding. Elements corresponding to each other between different figures will be referred to by the same reference number, and explanation considered redundant may be omitted.
The display device of the present embodiment will be explained using a liquid crystal display device as an example.
The signal conversion circuit 10 includes, as shown in
Now, in the pixel structure of the display panel 21 (subpixel arrangement), the first pixel P1 includes subpixels of R, G1, and B, and the second pixel P2 includes subpixels of R, G2, and B, and the first pixels P1 and the second pixels P2 are arranged alternately in the horizontal and vertical directions. The SPR processor 13 performs rendering of the image signals to conform to the pixel structure. Note that, in the following description, the color control of the pixels P1 and P2 arranged in the horizontal direction will be explained while the same applies to the color control of the pixels P1 and P2 arranged in the vertical direction. Furthermore, in the pixel structures shown in
R: x=0.640, y=0.330
G: x=0.300, y=0.600
G1: x=0.394, y=0.587
G2: x=0.202, y=0.614
B: x=0.150, y=0.060
The first pixel P1 and the second pixel P2 each can independently represent color within the gamut.
In the present embodiment, the subpixel adjuster 12 prioritizes turning on of G1 or G2 and adjusts the color temperature of white with R and B in the white display of one pixel. Furthermore, in the reference gamut distribution of
Hereinafter, a specific example will be explained.
(1) Method of Displaying White
In the adjustment of subpixels, white can be represented by a combination of R, G1, and B, or a combination of R, G2, and B.
(2) SPR Process
The 4CF (R, G1, G2, and B) image adjusted by the subpixel adjuster 12 is converted into an image with subpixel arrangement of P1 (R, G1, and B) and P2 (R, G2, and B) by the SPR processor 13. In this example, pixels 1 and 2 of 4CF arranged side-by-side are converted into pixels with subpixel arrangement of P1 and P2 as shown in
If colors of pixels 1 and 2 of 4CF are represented by replacing them with the subpixel arrangement of P1 and P2, respectively, since G1 or G2 is omitted in P1 and P2, the colors cannot be achieved unless G1/G2 of the adjacent pixel is used. That is, in the pixel 1, white cannot be achieved without turning on G2 of the pixel 2 while white cannot be achieved without turning on G1 of the pixel 1 in the pixel 2. Thus, the resolution is lost when one pixel is displayed using two pixels. Especially, when G1 and G2 which are highly recognizable are both lit, the resolution decreases to approximately a half. Thus, in the present embodiment, white is achieved by a single pixel and is achieved by two pixels when it is tinged green.
As can be understood from
In the present embodiment, the color is achieved by one pixel to the crossing point 1 or the crossing point 2 to further increase the resolution, and the second pixel is used after the crossing point 1 or the crossing point 2. At that time, a change of ratio between subpixels R, G1, and B of pixel 1 (P1) and subpixel G2 of pixel 2 (P2) adjacent thereto becomes as in an example of
Note that, in
An algorithm to achieve the color change above will be explained.
G2=−0.51*R+1.28*G2+0.11*B (1)
G1=0.39*R+0.78*G2−0.08*B (2)
Now, if 4CF/2 output representing white is, as shown in
R=0.5−0.51*0.5=0.25
G1=0.5+1.28*0.5=1.14
G2=0.5−0.5=0
B=0.5+0.11*0.5=0.55
At that time, since G1 is above 1, a clipping process is performed to decrease G1 to 1 and the corresponding brightness is added to R, G2, and B as shown in
R=0.25+0.39*0.14=0.30
G1=1.14−0.14=1
G2=0+0.78*0.14=0.11
B=0.55−0.08*0.14=0.54
Here, R and B are two pixels and each are ½ darker, and thus, the signal level is doubled. At that time, since B is above 1, a clipping process is performed to decrease B to 1 and the residing 0.08 is distributed to the adjacent pixels.
R=0.3*2=0.6
G1=1
G2=0.11
B=0.54*2=1.08
Now, if 4CF/2 output representing white is, as shown in
R=0.5+0.39*0.5=0.7
G1=0.5−0.5=0
G2=0.5+0.78*0.5=0.89
B=0.5−0.08*0.5=0.46
At that time, no color is above 1, and a clipping process is not required. Here, R and B are two pixels and each are ½ darker, and thus, the signal level is doubled. At that time, since R is above 1, a clipping process is performed to decrease R to 1, and the residue is distributed to the adjacent pixels as shown in
R=0.7*2=1.40
G1=0
G2=0.89
B=0.46*2=0.92
Then, at the crossing point 1, if 4CF/2 output is, as shown in
R=0.25−0.51*0.5=0
G1=0.5+1.28*0.5=1.14
G2=0.5−0.5=0
B=0.25+0.11*0.5=0.31
At that time, since G1 is above 1, a clipping process is performed to decrease G1 to 1 and the corresponding brightness is added to R, G2, and B as shown in
R=0+0.39*0.14=0.06
G1=1.14−0.14=1
G2=0+0.78*0.14=0.11
B=0.31−0.08*0.14=0.30
Here, R and B are two pixels and each are ½ darker, and thus, the signal level is doubled as shown in
R=0.6*2=0.12
G1=1
G2=0.11
B=0.30*2=0.6
Then, at the crossing point 2, if 4CF/2 output is, as shown in
R=0.04+0.39*0.5=0.24
G1=0.5−0.5=0
G2=0.5+0.78*0.5=0.89
B=0.04−0.08*0.5=0
At that time, no color is above 1, and a clipping process is not required. Here, R and B are two pixels and each are ½ darker, and thus, the signal level is doubled as shown in
R=0.24*2=0.48
G1=0
G2=0.89
B=0*2=0
Then, if 4CF/2 output representing green is, as shown in
R=0−0.51*0.5=−0.25
G1=0.5+1.28*0.5=1.14
G2=0.5−0.5=0
B=0+0.11*0.5=0.05
At that time, since G1 is above 1, a clipping process is performed to decrease G1 to 1 and the corresponding brightness is added to R, G2, and B as shown in
R=−0.25+0.39*0.14=0.20
G1=1.14−0.14=1
G2=0+0.78*0.14=0.11
B=0.05−0.08*0.14=0.04
Here, R is represented as follows by transforming the formula (2).
R=2.53*G1−1.98*G2+0.21*B (3)
Thus, by the signal level conversion, each subpixel output will be as follows as shown in
R=−0.2+0.2=0
G1=1−2.53*0.2=0.5
G2=0.11+1.98*0.2=0.5
B=0.04−0.21*0.2=0
Then, if 4CF/2 output representing white is, as shown in
R=0+0.39*0.5=0.19
G1=0.5−0.5=0
G2=0.5+0.78*0.5=0.89
B=0−0.08*0.5=−0.04
At that time, no color is above 1, and a clipping process is not required. Here, B is represented as follows by transforming the formula (1).
B=4.73*R−11.96*G1−9.34*G2 (4)
Thus, by the signal level conversion, each subpixel output will be as follows as shown in
R=0.19−4.73*0.04=0
G1=11.96*0.04=0.5
G2=0.89−9.34*0.04=0.5
B=−0.04+0.04=0
With the algorithm explained above, the brightness of subpixels of P1 and P2 are determined, and thus, in the white display of one pixel, turning on of G1 or G2 is prioritized to adjust the color temperature of white with R and B, and the color temperature can be adjusted from the white point W to the crossing point 1 or the crossing point 2 without changing the brightness of G1 and G2. Thus, a single vertical line, horizontal line, and diagonal line of single color can be displayed with a straight line with RGBW, and the resolution can be maintained.
Note that, in the above-described embodiment, the liquid crystal display device is exemplified; however, the embodiment can be applied to a display device using an organic EL panel.
Furthermore, in the above-described embodiment, the referential gamut distribution is HDTV broadcast standard BT.709; however, the embodiment can be applied to other format images such as Adobe RGB, and DCI.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Number | Date | Country | Kind |
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2018-050128 | Mar 2018 | JP | national |
Number | Name | Date | Kind |
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20080062386 | Ito | Mar 2008 | A1 |
20180033382 | Tomizawa | Feb 2018 | A1 |
Number | Date | Country |
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2008046766 | Feb 2008 | JP |
2018021963 | Feb 2018 | JP |
Number | Date | Country | |
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20190287471 A1 | Sep 2019 | US |