TWI285862B - Color conversion method and circuit - Google Patents

Abstract

A color conversion method is described. The method includes the following steps. A first modification value is added to the maximum value among R, G, and B become a new maximum value. A second modification value is subtracted from the minimum value among R, G, and B become a new minimum value. A third modification value is added to the middle value among R, G, and B become a new middle value. A W is set to the minimum value among R, G, and B. Substitute the maximum value, the middle value, and the minimum value of R, G, and B for the new maximum value, the new middle value and the new minimum value become modified R, G, and B. The modified R, G, B, and W are used as an output red brightness, an output green brightness, an output blue brightness, and an output white brightness respectively.

Description

1285862 IX. Description of the Invention: [Technical Field] The present invention relates to a liquid crystal display, and more particularly to a high brightness liquid crystal display. [Prior Art] A pixel arrangement of a conventional liquid crystal panel (LCD panel) is formed by mixing colors of three primary colors of R (red), G (green), and B (blue). Figure 1 shows an example of changing a pixel from the original three colors to four colors. In order to increase the brightness and change the resolution without affecting the resolution, the original three colors are changed to four colors. The color increases the portion of W, that is, the higher penetration of the sub-pixel, which increases the brightness of the overall liquid crystal panel. This color mixing method is called a multi-primary color mixing system, and has the advantages of solving the problem that the color filter of the liquid crystal panel (c〇l〇r-filter) increases the color saturation and causes the absorption backlight to be excessive, so that the overall liquid crystal panel has a reduced luminous intensity. The problem. Japanese Patent P2001-1476660A proposes a method of converting input R, G, B into output r, g, B. The concept of this patent is that in order to maintain the color saturation in the original state,

Rout, Gout, and Bout are all reduced by the minimum value of Min, R, G, and B, and a compensation value is added. This will cause the color saturation to be satisfied, but the brightness is increased. Therefore, how to design a new method can increase the brightness of the liquid crystal display panel, and can also take into account the R, G, B color saturation, which is very much needed by the industry! 285862 0 [Summary Therefore, an object of the present invention is to provide a color conversion method and circuit for a liquid crystal display, which can increase the brightness of the liquid crystal panel.

Another object of the present invention is to provide a color conversion method and circuit. This color conversion method can maintain the color saturation of the liquid crystal panel with a small color shift. It is still another object of the present invention to provide a color conversion method and circuit that can be directly attached to a liquid crystal display in a circuit type. According to the above object of the present invention, there is proposed a color conversion method for a liquid crystal display. The color conversion method comprises the following steps. Will be a r, ^ % eight knives " work one brother a correction value to become a new

$大值' where R is an original red luminance value, G is an original green luminance value, and B is an original blue luminance value. The first correction value is a positive number. The most of R, G, and B, 佶 anvil. You can subtract the second correction value from the value of J to the minimum value of =, where the second correction is a positive number. Add r, g to the middle value of the middle and add a r-th repair to the value of the value of R and r to become the new intermediate value. The newest and the smallest of B. Replace the original r, g, and " the nearest red, red, and red with the new maximum, two = and new intermediate values; , = green = two 8 1285862 output blue brightness value and an output white brightness value. In accordance with the purpose of the present invention, a color conversion circuit is proposed for use in a liquid crystal display. According to a preferred embodiment of the present invention, the color conversion circuit is a thief, a first correction circuit, a second correction circuit, a second correction circuit, and a W value generator. The comparator is used to resolve the maximum, ten, and minimum values in R, G, and B. Which is - the original red brightness value, G is a primitive

Green brightness value, B is the original blue brightness value. The first-correction circuit adds a maximum value of R, G, and B to a first correction value to become the new maximum

The value 'the first correction value is a positive number. The second correction circuit subtracts a minimum value of r, G, and B from a second correction value to become a new minimum value, wherein the second correction value is a positive number. The third correction circuit adds a third correction value to the intermediate value of R, G, and B to become a new intermediate value. The w value generator outputs the minimum of R, g, and B as a W value. The color conversion circuit replaces the maximum, minimum, and intermediate values of the original R, G, and B with the new maximum value, the new minimum value, and the new _ value, and obtains the corrected R, the corrected G, and the correction. After B, the corrected R, the corrected G, the corrected B and W are respectively regarded as an output red luminance, an output green luminance value, an output blue luminance value, and an output white luminance value. The present invention has at least the following advantages, each of which may have one or more advantages. The color conversion method and circuit of the present invention can increase the brightness of the liquid crystal panel. The color conversion method and circuit of the present invention can maintain the color saturation of the liquid crystal panel with a small color shift. The color conversion method and circuit of the present invention can be directly added to the liquid crystal display 1285862 in a circuit type. [Embodiment] Before describing an embodiment of the present invention, the problems encountered by the conventional RGBW display technology need to be slightly explained. If you simply compare the sub-pixel brightness with full open: In the RGB panel, each element has three sub-pixels, each of which is lost through the color filter. 2/3 brightness. Therefore, the total brightness is calculated as: 3 * ( 1/3 ) * ( 1/3 ) = 33% of which 3 sub-halogens, each sub-halogen accounts for 1/3 of the area of the panel, and each sub-tendin is color-filtered The output brightness is left (1/3). There are four sub-crystals in the RGBW panel, in which the white sub-pixel does not pass through the color filter, and the brightness of the color filter is not lost. Other sub-halogens lose 2/3 of the brightness through the color filter. Therefore, the total exemption is calculated as: 3*(1/4)*(1/3)+1 *(ι/4) * 1 = 50%. Where 3 * ( 1/4 ) * ( 1/3 ) represents R, 〇, b sub-pixels, 1 * (1/4) *1 represents white sub-pixel (white sub_pixel). After calculation, the RGBW panel will increase by 5% by the maximum brightness of the RGB panel. If the loss of aperture ratio is added (the RGBW panel has more enthalpy than the RGB panel, the aperture ratio will be smaller than the RGB panel) and the white sub-pixel will actually have some slight optical power loss. The maximum brightness of the RGBW panel is more than normal. The maximum brightness of the RGB panel is increased by 3〇%. While RGBWpanei has the advantage of increasing brightness over ordinary RGB panels, there is a problem of color shift and color saturation. When the color mixture is mixed and the values of R, G, and B are different, when a large amount of 1285862 increases the brightness of white scorpion, the color shift is severe. If the brightness of the white sub-pixel increases little, the overall brightness of the panel will not increase enough. — It is mathematically represented as follows: The ratio of each color of the input color is Rin :Gin:Bin· The ratio of each color of the output color is (R〇+ w〇) · (B〇+ w〇) ·(to + Wo) The most ideal state is Rin ·· Gin : Bin = (R〇+ w〇) : (b〇+ Wo) : (B〇+ Wo) However, in order to maintain the above formula, it is sometimes necessary to lower the output luminance value. Or the output brightness value rises 'but the color i is sacrificed (Rin: Gin: Bin (Ro + Wo) · (Bo + Wo) : (Bo + Wo)). When the color ratios are too large, there is a problem of chromatic aberration and color non-saturation. Therefore, the appropriate conversion equation is necessary. According to different r, g, b input signals, it is converted into new R, G, B, W output signals, and the result of the conversion must be able to maintain the original color and brightness. . In view of the shortcomings of the above RGBW display technology, the present invention provides an appropriate conversion formula. In the case of the same backlight, the brightness of the panel can be increased and the color saturation of the original display can be maintained. As will be described later and explained in detail, the algorithm will add more brightness and a smaller offset in chromatic aberration than the currently published algorithm. In an embodiment, the calculation method of the present invention includes: 1. First = processing the original red luminance value R, the original green luminance value G, and the original blueness value B data input to generate Mm (RGB) > Max(RGB) , Middle(RGB)^ Average(RGB) 〇1285862 2·Just judge the input data of the original red luminance value R, the original green luminance value G, and the original blue luminance value B, and judge which input signal It is the maximum 1", 'that-the one is the minimum value, and the different cases bring different formulas to do the calculation. # 'First classify the input data and then process it.

3. Add a function (first correction value) for the largest input signal, and subtract the - function (second correction value) for the smallest input signal, so that the color of the brightness output with white is not generated with the original input color. More deviations. In the example, ^functioi^InputData,

Average (RGB)? Min (RGB) 5 Max (RGB) 5 Middle (RGB)) Figure 2A shows the original (input) red (R), green (blue) (B) brightness values of an embodiment. Original input The luminance ratio of RGB is R:G:B=50:30:20=1:0.6:0.4 First, the input signal is judged, and the maximum value is added with a function to become the new maximum value; the minimum value is reduced by one. Function, to become the new minimum;; The value must also be processed according to the value of the value to become the new intermediate value; (for example, plus - the third correction value). W (white brightness value) will also (four) r, G And the minimum value of b. The new maximum value, the new minimum value, and the new intermediate value are substituted for the maximum, minimum, and intermediate values of the original R, G, and B, and the corrected R is obtained. G, corrected B. Then, the corrected R, the corrected G, the corrected B and w are respectively regarded as - output red luminance value, - output green luminance value, - output blue luminance value, and - output White brightness value. Figure 2B shows the brightness value of the red (8), green (9), and blue (B) after the function processing. After the function correction, the rgb is bright. The ratio is R:G:B=58:28:12. At this time, the 2C® shows the brightness values of red (R), green (6), and blue (8) 12 1285862 after adding white brightness. After the brightness of the white, the ratio of the colors of the output color is actually (Ro + Wo) : (Bo + Wo) : (Bo + Wo). (Ro + Wo) : (Bo + Wo) : (Bo + Wo) = (58+20) : (28+20) : (12+20)= 78 : 48 : 32 = 1 : 0.62 : 0.41. The brightness is obviously increased, and the ratio of each color is also very close to the original input value. Describe in detail how to convert the original RGB to a new RGBW conversion method. This conversion method can increase the RGBW panel.

Its brightness, and maintain the original color saturation. The conversion method is as follows: 1. Let the gray scale value of the input R be named R. Let the grayscale value of the input G be named G. Let the grayscale value of the input B be named B. 2. After the equation is converted, let the grayscale value of the output R be named R'. Let the grayscale value of the output G be named G'; let the grayscale value of the output B be named B'; The grayscale value is named W'.

R + G + B 3. Average (RGB) = 3 0 4. First select R, G, B. Maximum value = Max (RGB) Minimum value = Min (RGB) Intermediate value. = Mid (RGB) Average (RGB) - Min(RGB) 5·New_max - Mca(RGB) + Min(RGB) x 6· Let New_min = Min(RGB) - Min(RGB) x Avera?-e(RGHn-(RGB)

Average(RGB)

Average(RGB) 13 1285862 7·令 ^ _ mid = Mid (RGB) + Min{RGB) x AveragejRGB)

Average (RGB)

8. If R is the maximum of R, G, B, let R' = New_max; if R is the minimum of R, G, B, let R' = New - min; if R is the middle of R, G, B Value, let R'=New-mid. 9. If G is the maximum of R, G, and B, let G'=New_max; if G is the minimum of R'G and B, let G'=New-min; if G is the middle of R, G, and B. Value, let G'=New-mid. 10. If B is the maximum of R, G, and B, let B'=New_max; if B is the minimum of R, G, and B, let B'=New__min; if B is the intermediate value of R, G, and B, Let B'=New-mid. 11· W,=Min(RGB). For the first correction in the above steps

Average(RGB) - Min(RGB) Average(RGB) value

Min(RGB)x

Average(RGB) - Mirt(RGB) Average(RGB) is

υΓΡΛ - Mid(RGB) - Average^RGB)

Averagd^RGB) is the third correction value.

The present invention also provides a color conversion circuit 302 for a liquid crystal display. Figure 3 illustrates an embodiment of one of the color conversion circuits 302 of the present invention. The input red (R), green (G), and blue (B) signals represent their luminance values as Rin 3 18, Gin 320, and Bin 322, respectively. The comparator 304 is configured to distinguish the maximum value Max (RGB), the intermediate value Mid (RGB), and the minimum value Min (RGB) among Rin 318, Gin 320, and Bin 322. The comparator 304 outputs Max (RGB) ' Mid (RGB) and Min (RGB) to the first correction circuit 310, the second correction circuit 312, and the third correction circuit 314. W value generator 305 selects 14 1285862

Min (RGB) is output as a W value. The average circuit 307 calculates:

R+G+B

Average (RGB) = 3; wherein Average (RGB) is used by the first correction circuit 310, the first correction circuit 312, and the third correction circuit 328 to calculate the first correction value, the second correction value, and the third correction value, respectively. The first correction circuit 310 performs:

New _ max = Max(RGB) + Min(RGB):

Average (RGB) _ Min (RGB) Average (RGB) calculation The second correction circuit 312 performs: New min = Min(RGB) — Min(RGB) x

Average (RGB) - Min (RGB) Average (RGB) calculation The third correction circuit 314 performs:

New inid = Mid{KGB>) + Min^RGB):

Mid {RGB) - Average {RGB) Average (RGB) calculation judging block 306 receives Rin 318, Gin 320, Bin 322 and determines how to classify n 3, Gin 32 〇, Bin 322 to the first correction circuit 310, the second correction circuit 312, and the third correction circuit 314 operate. The multiplexer 308 receives the magic 11 318, Gin 320, Bin 322 and distributes it to the first correction circuit 310, the second correction circuit 312, and the third correction circuit 314. The values calculated by the first correction circuit 310, the second correction circuit 312, and the third correction circuit 314 are then distributed via the multiplexer 316 to output the correct red 15 1285862

The brightness of Rout 324, green Gout 326, and blue Bout328. The details of the operation of the color conversion circuit 302 are the same as those described above, and will not be described here. Rin=50; Gin=30; Bin=20 is used as a comparative example. The actual calculations of the present invention are compared to two conventional methods. Rin : Gin : Bin = 1 : 0.6 : 0·4 〇 • The calculation result of the present invention:

Ro=58 φ Go=28

Bo=12

Wo=20 (Ro + Wo) : (Bo + Wo) : (Bo + Wo) = (58+20): (28+20) : (12+20) =78:48:32= 1 : 0.62 : 0.41

Ro+Go+Bo+3 * Wo= 158 Japanese patent (Japan Patent P2001-1476660A) calculation result Ro=50 Go=22 Bo=8 Wo=20 (Ro + Wo) : (Bo + Wo) : (Bo + Wo) = (50+20): (22+20) : (8+20) =70:42:28= 1 : 0.6 : 0.4

Ro+Go+Bo+3 *Wo= 140 The calculation result of another paper (40.5L: Late-News Paper: TFTJLCD with 16 1285862 RGBW Color System):

Ro=50

Go=30

Bo=20

Wo=40 , (Ro + Wo) : (Bo + Wo) : (Bo + Wo) = (50+40): (30+40) : (20+40) =90:70:60= 1 : 0.78 : 0.67 # Ro+Go+Bo+3*Wo= 220 It can be found from the comparison of the above algorithms that the calculation results of the present invention and the Japanese patent (Japan Patent P2001-1476660A) both meet the requirements of chromatic aberration, but the display brightness is expressed by the present invention. Preferably (about 10% more). In addition, the algorithm of another paper can increase the brightness of the panel in a large amount, but the color shift is large. The present invention has at least the following advantages, each of which may have one or more advantages. The color conversion method and circuit of the present invention can increase the brightness of the liquid crystal panel. The color conversion method and circuit of the present invention can maintain the color saturation of the liquid crystal panel with a small color shift. The color conversion method and circuit of the present invention can be directly attached to the liquid crystal display in a circuit type. Although the present invention has been described above in terms of a preferred embodiment, it is not intended to limit the invention, and it is obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS [0009] The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood. An example of changing from the original three colors to four colors; Figure 2A shows the luminance values of the original (input) red (R), green (G), and blue (B) of an embodiment; The luminance values of red (R), green (G), and blue (B) after a function processing; Figure 2C shows the luminances of red (R), green (G), and blue (B) after adding white luminance Values; and Figure 3 illustrates an embodiment of one of the color conversion circuits 302 of the present invention. [Main Element Symbol Description] 302: Color Conversion Circuit 305 · W Value Generator 307: Average Circuit 310: First Correction Circuit 314: Third Correction Circuit 318: Rin 322: Bin 326 · Gout 304: Comparator 306 : Judgment circuit 308 : multiplexer 312 : second correction circuit 3 16 : multiplexer 320 : Gin 324 : Rout 328 : Bout 18

Claims (1)

1285862 X. Patent application scope: 1. - A color conversion method for - liquid crystal display, the color conversion method includes: adding a maximum value of a R, a G, and a B - a first correction value to become a new maximum value, wherein the original red luminance value, the G is an original green luminance value, the B is an original blue luminance value, the first correction value is a positive number; the R, the G, and the B The minimum value is subtracted from a second correction value to become a new minimum value, wherein the second correction value is a positive number; the intermediate value of the R, sH, and ahai B is added to a third value Correcting the value to become a new intermediate value; setting a W value to the R, the 〇, and the minimum of the b; and, with the new maximum value, the new minimum value, and the new intermediate value Take = the maximum, minimum, and intermediate values of the original R, G, and B, and know the corrected R, the corrected G, and the corrected B, the corrected R, the corrected G, The corrected B and the W are respectively regarded as an output red luminance value and an output green luminance. , A blue luminance output values and a white luminance value. 2. The color conversion method according to claim 1, wherein the first correction value of 5 hai is equal to the second correction value. 19 1285862 3. The color conversion method described in claim 1 of the patent scope further includes: Calculation New _ max = Max(RGB) + Min(RGB) x Average(RGB) - Min(RGB) Average(RGB) Where New-max is the new maximum value, Average (RGB) R + G + B = -~3 - -, Max (RGB) is the maximum value of the R, the G and the B, and Min (RGB) is the R, the minimum value of the G and the B, the first modified Average (RGB) ~ Min (RGB) Average (RGB) 4_, as described in the scope of claim 1, the color conversion method further includes New __ min = Min(RGB) ~ Min(RGB)) Average (RGB) - Min(RGB) Average {RGB) where New_min is the new minimum value, Average (RGB) R + G + B = 3 , The Min (RGB) is the minimum value of the R, the G, and the B, and the second correction value is Average (RGB) - Min (RGB) Average (RGB) 5. As described in claim 1 The color conversion method further includes: Computation 20 1285862, Shi (leak) + M (male; where New-mid is the new intermediate value, Average (RGB) R + G + B = 3, the Min (RGB) For the minimum of the R, the G, and the B, the Mid (RGB) is the intermediate value of the R, the G, and the B, and the third trimming (RGB) - Average (RGB) Average (RGB) ο positive value is stealing (Λσ5)χ 6. A color conversion circuit for a liquid crystal display, the color conversion circuit includes: a comparator for distinguishing a maximum value of R, a G, and a 、, The intermediate value and the minimum value, wherein the R is an original red luminance value, the G is an original green luminance value, and the chirp is an original blue luminance value; a first correction circuit, the R, the G, and the β In the middle The large value is added with a first correction value to become a new maximum value, and the first correction value is a positive number; a second correction circuit subtracts a minimum value of the R, the G, and the β Correcting the value to become a new minimum value, wherein the second correction value is a positive number; a third correction circuit adding a third correction value to the intermediate value of the R, the G, and the β to become new Intermediate value; a W value generator that outputs the minimum value of R, the G, and the Β as a W value; and wherein the color conversion circuit has a new maximum value, a new minimum value, and a new intermediate value Substituting the maximum and minimum values of the original R, G, and Β to 21 1285862 and the intermediate value, the corrected R, the corrected G, and the corrected B are obtained, and the corrected R and the corrected G. The corrected B and the W are respectively regarded as an output red luminance value, an output green luminance value, an output blue luminance value, and an output white luminance value. [7] as described in claim 6 a color conversion circuit, in the stomach, the first correction value and the first The correction value is equal. 8. The color conversion circuit as described in claim 6 further includes an average value circuit for calculation: R + G + B Average (RGB) = 3; wherein the Average (RGB) respectively The first correction circuit, the second correction circuit, and the third correction circuit calculate the first correction value, the second correction value, and the third correction value. 9. The color conversion circuit of claim 6, wherein the first correction circuit calculates New _ max = Max (RGB) + Min (RGB) x Average (RGB) - Min (RGB) Average (RGB) Where New_max is the new maximum value, Average (RGB) R+G+β ~ two ~~3 one-, Max(RGB) is the maximum value of the R, the G and the B, and Min(RGB) is the R The minimum value of the G and the B, the first correction value is Mii<RGB)x Average(RGB) - Min(RGB) Average(RGB) 22 1285862 10·The color as described in claim 6 a conversion circuit, wherein the second correction circuit calculates New _ min = Min{RGB) ~ Min(RGB) x ^-ageiRGB) ^ Mm(RGB) · Average {RGB) , where New_min is the new minimum value, Average (RGB) R + G + B = 3 , the Min (RGB) is the minimum of the R, the G, and the B, and the second correction is Average (RGB) - Min (RGB) Average (RGB) 11. The color conversion circuit of claim 6, wherein the third correction circuit calculates New-mid as a new intermediate value, Average (RGB) R + G + B = Γ ,, the Min (RGB) is the minimum of the R, the G, and the B, the Mid (RGB) is the intermediate value of the R, the G, and the B, the third correction value is Stealing (J?G5) X Mid(RGB) - Average(RGB) Average (RGB) 23 1285862 VII. Designation of representative map (1) The representative representative of this case is: (3) (II), representative of the case BRIEF DESCRIPTION OF THE SYMBOLS of the figure: 302: Color conversion circuit 304: Comparator 305: W value generator 306: Judgment circuit 307: Average value circuit 308: Multiplexer 310: First correction circuit 312: Second correction circuit 314 : Third correction circuit 316 : multiplexer 318 : Rin 320 : Gin 322 : Bin 324 : Rout 326 : Gout 328 : Bout 8. If there is a chemical formula in this case, please disclose the chemical formula that best shows the characteristics of the invention: