JP5358918B2 - Driving method of liquid crystal display element - Google Patents

Driving method of liquid crystal display element Download PDF

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JP5358918B2
JP5358918B2 JP2007255799A JP2007255799A JP5358918B2 JP 5358918 B2 JP5358918 B2 JP 5358918B2 JP 2007255799 A JP2007255799 A JP 2007255799A JP 2007255799 A JP2007255799 A JP 2007255799A JP 5358918 B2 JP5358918 B2 JP 5358918B2
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哲也 楠野
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Casio Computer Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To cause a liquid crystal display device wherein one display element comprises pixels of four colors of red, green, blue, and white, to display a color image of high color reproducibility. <P>SOLUTION: On the basis of input gradation data of three colors of red, green, and blue, ratios of brightness corresponding to gradation data for driving pixels of four colors of red, green, blue, and white, to respective maximum gradation brightness of these pixels are defined as brightness rates, and maximum values out of absolute values of differences between brightness rates of pixels of three colors of red, green, and blue per display element are defined as maximum brightness rate differences. Driving gradation data of four colors of red, green, blue, and white per display element is set so that brightness rates of the plurality of display elements become values resulting from adding a brightness rate of a ratio corresponding to the number of gradations other than the number of gradation corresponding to a maximum brightness rate difference of set brightness rates having arbitrary values predetermined in accordance with characteristics of white pixels, to respective brightness rates of pixels of three colors of red, green, and blue and multiplying addition results by a coefficient determined in accordance with maximum brightness differences of all display elements in one frame and subtracting brightness rates of white pixels. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

この発明は、三原色及び白の各色1つずつの4つの画素を1単位とする複数の表示要素によりカラー画像を表示する液晶表示素子の駆動方法に関する。   The present invention relates to a driving method of a liquid crystal display element that displays a color image by a plurality of display elements each including four pixels of three primary colors and white as one unit.

従来、カラー液晶表示素子(以下、3色画素表示素子という)は、赤、緑、青の3色の画素により1つの表示要素を構成し、1つの色を定義するために入力された赤、緑、青の3色の階調データに応て、前記3色の階調データに対応する赤、緑、青の3色のデータ信号を前記赤、緑、青の3色の画素にそれぞれ供給することにより駆動されている。 Conventionally, a color liquid crystal display element (hereinafter, referred to as a three-color pixel display element) is configured to form one display element with pixels of three colors of red, green, and blue, and input red to define one color, green, Ji three colors response to the gradation data of the blue, red corresponding to the gradation data of the three colors, respectively green, the three colors of the data signals of blue, red, green, three colors of pixels and blue It is driven by supplying.

この3色画素表示素子に対して、明るい画像を表示するために、例えば赤、緑、青の三原色及び白の4色の複数の画素が交互にマトリックス状に配列させて形成され、互いに隣合う赤、緑、青及び白の各色1つずつの4つの画素を1単位とする複数の表示要素によりカラー画像を表示する液晶表示素子が提案されている(特許文献1参照)。   In order to display a bright image on the three-color pixel display element, for example, a plurality of pixels of four primary colors of red, green, and blue and white are alternately arranged in a matrix and are adjacent to each other. There has been proposed a liquid crystal display element that displays a color image by a plurality of display elements each including four pixels of red, green, blue, and white as one unit (see Patent Document 1).

この液晶表示素子は、赤、緑、青の3色の画素に白色の画素を加えた4色の画素により1つの表示要素を構成しているため、画面を明るくすることができる。   In this liquid crystal display element, one display element is composed of four color pixels in which white pixels are added to three color pixels of red, green, and blue, so that the screen can be brightened.

前記赤、緑、青及び白の4色の画素により1つの表示要素を構成した液晶表示素子は、入力された赤、緑、青の3色の階調データに基づいて、これらの3色の階調データのうちの最小値の階調データからバイアス値を演算により定めてその値を白色画素の駆動階調データとし、前記入力された赤、緑、青の3色の階調データからそれぞれ前記白色画素の駆動階調データの階調値を減算して赤、緑、青の3色の画素それぞれの駆動階調データを求め、これらの駆動階調データにそれぞれ対応した赤、緑、青及び白の4色のデータ信号を赤、緑、青及び白の4色の画素にそれぞれ供給する方法で駆動されている(特許文献2参照)。
特開平1−259396号公報 特開平4−130395号公報
The liquid crystal display element in which one display element is constituted by pixels of four colors of red, green, blue, and white is based on the input gradation data of three colors of red, green, and blue. A bias value is determined by calculation from the gradation data of the minimum value of the gradation data, and the value is used as driving gradation data for the white pixel, and each of the input gradation data of three colors of red, green, and blue is used. By subtracting the gradation value of the drive gradation data of the white pixel, the drive gradation data of each of the three colors of red, green, and blue is obtained, and red, green, blue corresponding to these drive gradation data, respectively. And white color data signals are supplied to the four color pixels of red, green, blue and white, respectively (see Patent Document 2).
JP-A-1-259396 Japanese Patent Laid-Open No. 4-130395

しかし、前記赤、緑、青及び白の4色の画素により1つの表示要素を構成した液晶表示素子(以下、4色画素表示素子という)を上記従来の駆動方法で駆動する液晶表示装置は、入力された赤、緑、青の3色の階調データに対応した色再現性の良いカラー画像を表示することができない。   However, a liquid crystal display device that drives a liquid crystal display element (hereinafter referred to as a four-color pixel display element) in which one display element is configured by pixels of four colors of red, green, blue, and white by the above-described conventional driving method, A color image with good color reproducibility corresponding to the input gradation data of three colors of red, green and blue cannot be displayed.

前記4色画素表示素子を上記従来の駆動方法で駆動する液晶表示装置は、入力された赤、緑、青の3色の階調データの階調値が互いに異なるとき、つまり前記赤、緑、青の3色の階調データが、赤、緑、青の3色を互いに異なる比率で混色させた中間色を定めたデータであるときに、前記4色画素表示素子による表示色に、従来の3色画素表示素子の表示色に対する色ずれが生じる。   In the liquid crystal display device that drives the four-color pixel display element by the conventional driving method, when the gradation values of the input three-color gradation data of red, green, and blue are different from each other, that is, the red, green, When the gradation data of the three colors of blue is data defining intermediate colors obtained by mixing the three colors of red, green, and blue at different ratios, the display color by the four-color pixel display element is changed to the conventional 3 A color shift occurs with respect to the display color of the color pixel display element.

例えば、入力された赤、緑、青の3色の階調データがそれぞれ階調値が0〜63の64階調のデータであり、また、前記3色画素表示素子及び4色画素表示素子の各色の画素それぞれの輝度がこれらの画素を駆動するための駆動階調データの階調値に比例する場合、入力された赤、緑、青の3色の階調データのうちの赤の階調データの階調値が47、緑の階調データの階調値が29、青の階調データの階調値が15のとき、1つの表示要素の表示の色度、つまりx,yコーディネイト値は、前記3色画素表示素子を前記赤、緑、青の3色の階調データに対応した3色のデータ信号を赤、緑、青の3色の画素にそれぞれ供給することにより駆動したときはx=0.38,y=0.38であるのに対して、前記4色画素表示素子を前記従来の駆動方法により駆動したときはx=0.35,y=0.36である。   For example, the input gradation data of three colors of red, green, and blue are 64 gradation data having gradation values of 0 to 63, respectively, and the three-color pixel display element and the four-color pixel display element. When the luminance of each color pixel is proportional to the gradation value of the drive gradation data for driving these pixels, the red gradation of the input gradation data of three colors of red, green, and blue When the gradation value of the data is 47, the gradation value of the green gradation data is 29, and the gradation value of the blue gradation data is 15, the display chromaticity of one display element, that is, the x, y coordinate values. When the three-color pixel display element is driven by supplying three-color data signals corresponding to the three-color gradation data of red, green, and blue to the three-color pixels of red, green, and blue, respectively. X = 0.38 and y = 0.38, while the four-color pixel display element is driven in the conventional manner. When it is driven by law x = 0.35, a y = 0.36.

このように、前記4色画素表示素子を上記従来の駆動方法で駆動する液晶表示装置は、入力された赤、緑、青の3色の階調データが中間色を定めたデータであるときに表示色に色ずれが生じ、入力された赤、緑、青の3色の階調データに対応した色再現性の良いカラー画像を表示することができない。   As described above, the liquid crystal display device that drives the four-color pixel display element by the above-described conventional driving method displays when the input gradation data of the three colors of red, green, and blue is data that defines an intermediate color. A color shift occurs, and a color image with good color reproducibility corresponding to the input gradation data of three colors of red, green, and blue cannot be displayed.

この発明は、三原色及び白の4色の画素により1つの表示要素を構成した液晶表示素子を色再現良く表示させることができる駆動方法を提供することを目的としたものである。 An object of the present invention is to provide a driving method that can display a liquid crystal display element in which one display element is composed of pixels of three primary colors and white, with good color reproduction.

前記課題を解決するため、本発明の液晶表示素子の駆動方法の一態様は、赤、緑、青及び白の4色の複数の画素が交互にマトリックス状に配列させて形成され、互いに隣合う前記赤、緑、青及び白の各色1つずつの4つの画素を1単位とする複数の表示要素によりカラー画像を表示する液晶表示素子の駆動方法において、入力された赤、緑、青の3色の階調データに基づいて、前記赤、緑、青及び白の4色の画素それぞれの最大階調輝度をLmaxR,LmaxG,LmaxB,LmaxW、前記赤、緑、青の3色の画素それぞれの前記入力された赤、緑、青の3色の階調データに対応する輝度を入力データ対応輝度L,L,L、前記赤、緑、青の3色の画素それぞれの前記最大階調輝度LmaxR,LmaxG,LmaxBに対する前記入力データ対応輝度L,L,Lの割合L/LmaxR,L/LmaxG,L/LmaxBをそれぞれ入力データ対応輝度率R,R,R、前記複数の表示要素毎の前記赤、緑、青の3色の画素相互の前記入力データ対応輝度率R,R,Rの差の絶対値|R−R|,|R−R|,|R−R|のうちの最大値を最大輝度率差dmax、1画面のカラー画像を表示するための1フレームにおける全ての表示要素それぞれの前記最大輝度率差dmaxのうちの最も大きい値をdmaxALL前記入力された赤、緑、青の3色の階調データの階調値をD ,D ,D 、前記複数の表示要素毎の赤、緑、青及び白の4色の駆動階調データの階調値をD′ ,D′ ,D′ ,D′ 、とするとき、前記液晶表示素子は、前記赤、緑、青及び白の4色の画素それぞれの輝度がこれらの画素を駆動するための前記駆動階調データの階調値に比例する特性を有しており、D′ はD {1+t (1−d max )}t −Cを整数化した値、D′ はD {1+t (1−d max )}t −Cを整数化した値、 D′ はD {1+t (1−d max )}t −Cを整数化した値、D′ はCを整数化した値、ただし、Cは、D {1+t (1−d max )}t ,D {1+t (1−d max )}t ,D {1+t (1−d max )}t のうちの最も小さい値をD 2min とするとき、当該D 2min が最大階調未満の場合は当該D 2min を整数化した値、当該D 2min が最大階調以上の場合は前記最大階調の値、また、t は、0≦t ≦L maxW /(L maxR +L maxG +L maxB )の範囲の任意の設定値、t は、1/[{1+t (1−d maxALL )}d maxALL ]≦{1+L maxW /(L maxR +L maxG +L maxB )}/(1+t )のとき、t =1/[{1+t (1−d maxAL L)}d maxALL ]に設定され、{1+L maxW /(L maxR +L maxG +L maxB )}/(1+t )<1/[{1+t (1−d maxALL )}d maxALL ]のとき、t ={1+L maxW /(L maxR +L maxG +L maxB )}/(1+t )に設定される、係数、にそれぞれ設定される、ことを特徴とする。 In order to solve the above problems, one embodiment of a method for driving a liquid crystal display element according to the present invention is formed by alternately arranging a plurality of pixels of four colors of red, green, blue, and white in a matrix and adjacent to each other. In the driving method of a liquid crystal display element that displays a color image by a plurality of display elements each including four pixels of each of red, green, blue, and white as one unit, the input red, green, and blue 3 Based on the color gradation data, the maximum gradation luminance of each of the red, green, blue and white pixels is represented by L maxR , L maxG , L maxB , L maxW , and the three colors of red, green and blue. The luminances corresponding to the inputted red, green, and blue gradation data of each of the pixels are input data corresponding luminances L R , L G , and L B , and the red, green, and blue three-color pixels respectively. The maximum gradation luminances L maxR , L maxG , L ma The relative xB input data corresponding luminance L R, L G, L the proportion of B L R / L maxR, L G / L maxG, L B / L maxB respective input data corresponding luminance factor R R, R G, R B , the red for each of the plurality of display elements, green, the input data corresponding luminance of the pixels mutual three colors blue R R, R G, the absolute value of the difference between R B | R R -R G | , | R G -R B |, | R B -R R | has a maximum value of the maximum luminance rate difference d max , and the maximum luminance rate difference d of each display element in one frame for displaying a color image of one screen. The largest value of max is d maxALL , the gradation values of the inputted red, green, and blue gradation data are D R , D G , D B , red for each of the plurality of display elements, The gradation values of the drive gradation data of green, blue and white are represented by D ′ R , D ′. When G 1 , D ′ B , and D ′ W , the liquid crystal display element has the drive gradation data for driving the pixels of the four colors of red, green, blue, and white, respectively. D ′ R is a value obtained by converting D R {1 + t 1 (1−d max )} t 2 −C into an integer, and D ′ G is D G {1 + t 1 ( 1-d max)} t 2 -C integer of value, D 'B is D B {1 + t 1 ( 1-d max)} t 2 -C integer of value, D' W is an integer of a C Where C is D R {1 + t 1 (1−d max )} t 2 , D G {1 + t 1 (1−d max )} t 2 , D B {1 + t 1 (1−d max )} when the smallest value of the t 2 and D 2min, if the D 2min is less than the maximum gradation the D 2min integer When the D 2min is equal to or greater than the maximum gradation, the maximum gradation value is set, and t 1 is an arbitrary setting in the range of 0 ≦ t 1 ≦ L maxW / (L maxR + L maxG + L maxB ) value, t 2 is, 1 / [{1 + t 1 (1-d maxALL)} d maxALL] ≦ {1 + L maxW / (L maxR + L maxG + L maxB)} / (1 + t 1) when, t 2 = 1 / [ is set to {1 + t 1 (1- d maxAL L)} d maxALL], {1 + L maxW / (L maxR + L maxG + L maxB)} / (1 + t 1) <1 / [{1 + t 1 (1-d maxALL)} when d MAXALL], is set to t 2 = {1 + L maxW / (L maxR + L maxG + L maxB)} / (1 + t 1), the coefficient, it It is set, characterized in that.

この発明の駆動方法によれば、色再現性の良いカラー画像を表示させることができる。   According to the driving method of the present invention, a color image with good color reproducibility can be displayed.

図1は液晶表示装置の構成図であり、この液晶表示装置は、加法混色における赤、緑、青の三原色及び白の4色の複数の画素13R,13G,13B,13W(図2参照)が交互にマトリックス状に配列させて形成された液晶表示素子1と、入力された前記三原色(赤、緑、青の3色)の階調データに基づいて赤、緑、青及び白の4色の階調データを生成し、4つの各画素を備えた前記液晶表示素子1を駆動する駆動手段15とにより構成されている。 FIG. 1 is a configuration diagram of a liquid crystal display device, and this liquid crystal display device has a plurality of pixels 13R, 13G, 13B, and 13W (see FIG. 2) of four primary colors of red, green, and blue in additive color mixture and three colors of white. Based on the liquid crystal display elements 1 that are alternately arranged in a matrix and the input gradation data of the three primary colors (red, green, and blue), the four colors red, green, blue, and white are displayed. drive means 15 for generating gradation data, for driving the liquid crystal display device 1 with four pixels, and is configured by.

図2は前記液晶表示素子1の一部分の断面図であり、この液晶表示素子1は、予め定めた間隙を設けて対向配置された一対の透明基板2,3と、これらの基板2,3間の間隙に封入された液晶層4と、前記一対の基板2,3の一方、例えば観察側(図において上側)とは反対側の基板2の内面に、行方向(画面の左右方向)及び列方向(画面の上下方向)にマトリックス状に配列させて形成された複数の透明な画素電極5と、他方の基板、つまり観察側の基板3の内面に、前記複数の画素電極5の配列領域に対応させて形成された一枚膜状の透明な対向電極6と、前記一対の基板2,3の外面にそれぞれ配置された一対の偏光板11,12とからなっている。 FIG. 2 is a cross-sectional view of a part of the liquid crystal display element 1. The liquid crystal display element 1 includes a pair of transparent substrates 2 and 3 that are arranged to face each other with a predetermined gap therebetween, and between these substrates 2 and 3. On the inner surface of one of the pair of substrates 2 and 3, for example, the opposite side to the observation side (upper side in the figure), and in the row direction (horizontal direction of the screen) and the column A plurality of transparent pixel electrodes 5 arranged in a matrix in the direction (vertical direction of the screen) and the inner surface of the other substrate, that is, the substrate 3 on the observation side, in the arrangement region of the plurality of pixel electrodes 5 a single film-like transparent counter electrode 6 formed in correspondence, and a pair of polarizing plates 11 and 12 respectively disposed on an outer surface of the pair of substrates 2 and 3, is made of.

この液晶表示素子1は、TFT(薄膜トランジスタ)を能動素子としたアクティブマトリックス液晶表示素子であり、図1では省略しているが、前記複数の画素電極5が形成された反対側基板2の内面に、前記複数の画素電極5にそれぞれ対応させて配置され、これらの画素電極5にそれぞれ接続された複数のTFTと、各行のTFTにゲート信号を供給するための複数の走査線と、各列のTFTにデータ信号を供給するための複数のデータ線とが設けられている。 The liquid crystal display element 1 is an active matrix liquid crystal display element using TFTs (thin film transistors) as active elements, and although not shown in FIG. 1, the liquid crystal display element 1 is formed on the inner surface of the opposite substrate 2 on which the plurality of pixel electrodes 5 are formed. , A plurality of TFTs arranged corresponding to the plurality of pixel electrodes 5, respectively, connected to these pixel electrodes 5, a plurality of scanning lines for supplying gate signals to the TFTs in each row, a plurality of data lines for supplying data signals to the TFT, is provided.

この液晶表示素子1は、その観察側とは反対側に配置された図示しない面光源から照射された光の透過を制御して画像を表示するものであり、前記複数の画素電極5と前記対向電極6とが互いに対向する領域により、前記データ信号の供給、つまり前記電極5,6間への前記データ信号に対応した電圧の印加により前記液晶層4の液晶分子の配向状態を変化させて光の透過を制御する複数の画素13R,13G,13B,13Wが形成されている。 The liquid crystal display element 1 displays an image by controlling the transmittance of light emitted from a surface light source (not shown) disposed on the side opposite to the observation side. The alignment state of the liquid crystal molecules in the liquid crystal layer 4 is changed by supplying the data signal, that is, by applying a voltage corresponding to the data signal between the electrodes 5 and 6 depending on the region facing the counter electrode 6. a plurality of pixels 13R for controlling the transmittance of light, 13G, 13B, 13W are formed.

前記複数の画素13R,13G,13B,13Wのうちの1/4の数の画素13Rは、赤色カラーフィルタ7Rを備えた赤色画素、他の1/4の数の画素13Gは、緑色カラーフィルタ7Gを備えた緑色画素、さらに他の1/4の数の画素13Bは、青色カラーフィルタ7Bを備えた青色画素、残りの1/4の数の画素13Wは、カラーフィルタを備えない白色画素であり、前記赤、緑、青及び白の各色の複数の画素13R,13G,13B,13Wが、交互にマトリックス状に配列させて形成されている。   Of the plurality of pixels 13R, 13G, 13B, and 13W, 1/4 of the pixels 13R are red pixels including the red color filter 7R, and the other 1/4 of the pixels 13G are green color filters 7G. A green pixel having a color filter, and another 1/4 pixel 13B are a blue pixel having a blue color filter 7B, and the remaining 1/4 pixel 13W is a white pixel having no color filter. The plurality of pixels 13R, 13G, 13B, and 13W of the colors red, green, blue, and white are alternately arranged in a matrix.

前記カラーフィルタ7R,7G,7Bは、前記一対の基板2,3のいずれか一方、例えば観察側基板3の内面に形成されており、さらに前記観察側基板3の内面には、前記白色画素13Wにそれぞれ対応させて、この白色画素13Wの液晶層厚を、前記赤、緑、青の3色の画素13R,13G,13Bの液晶層厚と同程度に調整するための無色の透明膜8が形成されている。   The color filters 7R, 7G, and 7B are formed on one of the pair of substrates 2 and 3, for example, on the inner surface of the observation side substrate 3, and further on the inner surface of the observation side substrate 3, the white pixel 13W. The colorless transparent film 8 for adjusting the thickness of the liquid crystal layer of the white pixel 13W to the same level as the thickness of the liquid crystal layers of the three colors red, green, and blue 13R, 13G, and 13B is provided. Is formed.

なお、前記対向電極6は、前記カラーフィルタ7R,7G,7B及び前記無色の透明膜8の上に形成されており、また、前記一対の基板2,3の内面にはそれぞれ、前記複数の画素電極5及び対向電極6を覆って配向膜9,10が設けられている。   The counter electrode 6 is formed on the color filters 7R, 7G, and 7B and the colorless transparent film 8, and the inner surfaces of the pair of substrates 2 and 3 respectively include the plurality of pixels. Alignment films 9 and 10 are provided so as to cover the electrode 5 and the counter electrode 6.

そして、前記一対の基板2,3は、予め定めた間隙を設けて対向配置され、前記複数の画素13R,13G,13B,13Wがマトリックス状に配列された画面領域を囲む枠状のシール材(図示せず)を介して接合されており、これらの基板2,3間の前記シール材で囲まれた領域に液晶層4が封入されている。   The pair of substrates 2 and 3 are arranged to face each other with a predetermined gap therebetween, and a frame-shaped sealing material (a frame-shaped sealing material surrounding the screen region in which the plurality of pixels 13R, 13G, 13B, and 13W are arranged in a matrix form) The liquid crystal layer 4 is sealed in a region surrounded by the sealing material between the substrates 2 and 3.

この液晶表示素子1は、前記液晶層4の液晶分子をツイスト配向させたTNまたはSTN型、液晶分子を基板2,3面に対して垂直に配向させた垂直配向型、液晶分子をツイストさせることなく基板2,3面に対して平行に配向させた水平配向型、液晶分子をベンド配向させるベンド配向型のいずれか、あるいは強誘電性または反強誘電性液晶表示素子であり、前記一対の偏光板11,12は、それぞれの透過軸の向きを、各画素13R,13G,13B,13Wの電極5,6間に電圧を印加しないときの表示が黒または白になるように設定して配置されている。 The liquid crystal display device 1, the liquid crystal layer 4 TN or STN type and the liquid crystal molecules are twisted in the liquid crystal molecules with respect to the substrate 2 side vertically into oriented so the vertical alignment type, thereby twisting the liquid crystal molecules horizontal alignment type has been oriented to the flat row with respect to the substrate 2 side without any bend alignment type to bend alignment of the liquid crystal molecules, or a ferroelectric or anti-ferroelectric liquid crystal display device, the pair The polarizing plates 11 and 12 are set so that the direction of the respective transmission axes is black or white when no voltage is applied between the electrodes 5 and 6 of the pixels 13R, 13G, 13B, and 13W. Has been placed.

なお、図1に示した液晶表示素子1は、一対の基板2,3の内面それぞれに設けられた電極5,6間に電界を生じさせて液晶分子の配向状態を変化させるものであるが、それに限らず、一対の基板のいずれか一方の内面に、複数の画素を形成するための例えば櫛状の第1と第2の電極を設け、これらの電極間に横電界(基板面に沿う方向の電界)を生じさせて液晶分子の配向状態を変化させる横電界制御型のものでもよい。   The liquid crystal display element 1 shown in FIG. 1 changes the alignment state of liquid crystal molecules by generating an electric field between the electrodes 5 and 6 provided on the inner surfaces of the pair of substrates 2 and 3, respectively. For example, comb-like first and second electrodes for forming a plurality of pixels are provided on the inner surface of one of the pair of substrates, and a horizontal electric field (direction along the substrate surface) is provided between these electrodes. A lateral electric field control type in which the alignment state of the liquid crystal molecules is changed by generating an electric field).

前記液晶表示素子1は、互いに隣合う前記赤、緑、青及び白の各色1つずつの4つの画素13R,13G,13B,13Wを1単位とする複数の表示要素14によりカラー画像を表示する。   The liquid crystal display element 1 displays a color image by a plurality of display elements 14 each including four pixels 13R, 13G, 13B, and 13W for each of the red, green, blue, and white colors adjacent to each other. .

図3〜図6はそれぞれ前記液晶表示素子1の画素配列例を示しており、これらの図では、互いに隣合う4つの画素13R,13G,13B,13Wにより構成された複数の表示要素14をそれぞれ太線で囲んでいる。   3 to 6 show pixel arrangement examples of the liquid crystal display element 1, respectively. In these drawings, a plurality of display elements 14 each including four pixels 13R, 13G, 13B, and 13W adjacent to each other are shown. Surrounded by bold lines.

図3に示した画素配列例は、各行毎に、赤、緑、青及び白の4色の画素13R,13G,13B,13Wを、同じ順序、例えば赤色画素13R、白色画素13W、緑色画素13G、青色画素13Bの順で交互に並べて配列したものであり、各行毎に、互いに隣合う赤、緑、青及び白の各色1つずつの4つの画素13R,13G,13B,13Wからなる複数の表示要素14が構成されている。   In the pixel arrangement example shown in FIG. 3, red, green, blue, and white pixels 13R, 13G, 13B, and 13W are arranged in the same order, for example, red pixel 13R, white pixel 13W, and green pixel 13G for each row. The blue pixels 13B are alternately arranged in the order, and for each row, a plurality of four pixels 13R, 13G, 13B, and 13W each having a red, green, blue, and white color adjacent to each other are arranged. A display element 14 is configured.

図4に示した画素配列例は、各行毎に、赤、緑、青及び白の4色の画素13R,13G,13B,13Wを交互に、且つ奇数行と偶数行とで並び順を異ならせて配列したものであり、各行毎に、互いに隣合う赤、緑、青及び白の各色1つずつの4つの画素13R,13G,13B,13Wからなる複数の表示要素14が構成されている。   In the pixel arrangement example shown in FIG. 4, the pixels 13R, 13G, 13B, and 13W of four colors of red, green, blue, and white are alternately arranged in each row, and the order of arrangement is different between the odd rows and the even rows. A plurality of display elements 14 composed of four pixels 13R, 13G, 13B, and 13W for each color of red, green, blue, and white adjacent to each other are configured for each row.

図5に示した画素配列例は、奇数行に、赤、緑、青及び白の4色のうちの2つの色の画素、例えば赤色画素13Rと白色画素13Wとを交互に並べて配列し、偶数行に、前記赤、緑、青及び白の4色のうちの他の2つの色の画素、例えば緑色画素13Gと青色画素13Bとを交互に並べて配列したものであり、隣合う2つの行毎に、前記2つの行及び2つの列の赤、緑、青及び白の各色1つずつの4つの画素13R,13G,13B,13Wからなる複数の表示要素14が構成されている。   In the pixel arrangement example shown in FIG. 5, pixels of two colors of four colors of red, green, blue, and white, for example, red pixels 13R and white pixels 13W are alternately arranged in an odd row, and even numbers are arranged. In a row, pixels of the other two colors among the four colors of red, green, blue and white, for example, a green pixel 13G and a blue pixel 13B are alternately arranged and arranged for every two adjacent rows. In addition, a plurality of display elements 14 composed of four pixels 13R, 13G, 13B, and 13W for each of the red, green, blue, and white colors in the two rows and two columns are configured.

図6に示した画素配列例は、各行毎に、前記赤、緑、青及び白の4色の画素13R,13G,13B,13Wを交互に、且つ奇数行と偶数行とで並び順を異ならせて配列するとともに、前記奇数行の画素配列と前記偶数行の画素配列とを、行方向に1/2ピッチずらしたものであり、各行毎に、互いに隣合う赤、緑、青及び白の各色1つずつの4つの画素13R,13G,13B,13Wからなる複数の表示要素14が構成されている。   In the pixel arrangement example shown in FIG. 6, the red, green, blue, and white four-color pixels 13R, 13G, 13B, and 13W are alternately arranged in each row, and are arranged in an odd row and an even row. The odd-numbered pixel array and the even-numbered pixel array are shifted by ½ pitch in the row direction, and each row has red, green, blue and white adjacent to each other. A plurality of display elements 14 including four pixels 13R, 13G, 13B, and 13W for each color are configured.

なお、前記液晶表示素子1の画素配列は、前記図3〜図6の配列に限らず、互いに隣合う赤、緑、青及び白の各色1つずつの4つの画素13R,13G,13B,13Wにより1つの表示要素14を構成する配列であればよい。   The pixel arrangement of the liquid crystal display element 1 is not limited to the arrangement shown in FIGS. 3 to 6, and four pixels 13R, 13G, 13B, and 13W for each of red, green, blue, and white adjacent to each other. As long as it is an array that constitutes one display element 14.

この液晶表示素子1は、赤、緑、青及び白の4色の画素13R,13G,13B,13Wにより1つの表示要素14を構成しているため、白色画素を備えず、赤、緑、青の3色の画素により1つの表示要素を構成した3色画素表示素子に比べて、画面を明るくすることができる。   Since this liquid crystal display element 1 comprises one display element 14 by the pixels 13R, 13G, 13B, and 13W of four colors of red, green, blue, and white, no white pixel is provided, and red, green, and blue Compared to a three-color pixel display element in which one display element is configured by three color pixels, the screen can be brightened.

次に、前記液晶表示素子1の駆動方法を説明すると、前記液晶表示素子1は、図1に示した駆動手段15により、外部から入力された映像信号の赤、緑、青の3色の階調データに基づいて、前記複数の表示要素14毎の赤、緑、青及び白の4色の画素13R,13G,13B,13Wを駆動するための赤、緑、青及び白の4色の駆動階調データを生成し、これらの駆動階調データにそれぞれ対応した前記4色のデータ信号を前記複数の表示要素14の赤、緑、青及び白の4色の画素13R,13G,13B,13Wにそれぞれ供給することにより駆動する。   Next, a driving method of the liquid crystal display element 1 will be described. The liquid crystal display element 1 is divided into three levels of red, green, and blue of a video signal input from the outside by the driving means 15 shown in FIG. Based on the tone data, driving of the four colors red, green, blue and white for driving the pixels 13R, 13G, 13B and 13W of red, green, blue and white for each of the plurality of display elements 14 is performed. Gradation data is generated, and the four color data signals corresponding to the drive gradation data are respectively converted into the four color pixels 13R, 13G, 13B, and 13W of the plurality of display elements 14. It drives by supplying to each.

前記駆動手段15は、前記液晶表示素子1の複数の走査線に順次前記TFTをオンさせるためのゲート信号を供給する走査駆動回路16と、前記液晶表示素子1の複数のデータ線にデータ信号を供給するデータ駆動回路17と、前記映像信号の赤、緑、青の3色の階調データに基づいて前記液晶表示素子1の複数の表示要素14毎の赤、緑、青及び白の4色の駆動階調データを生成するための演算部18と、前記ゲート信号に対応した電圧及び前記赤、緑、青及び白の4色の駆動階調データの階調数に対応した複数の値の電圧を発生する電源部19と、前記走査駆動回路16及びデータ駆動回路17と演算部18を制御するコントローラ20とからなっている。 The driving unit 15 supplies a gate signal for sequentially turning on the TFT to a plurality of scanning lines of the liquid crystal display element 1 and a data signal to the plurality of data lines of the liquid crystal display element 1. Four colors of red, green, blue and white for each of the plurality of display elements 14 of the liquid crystal display element 1 based on the data drive circuit 17 to be supplied and the gradation data of the three colors of red, green and blue of the video signal. A plurality of values corresponding to the voltage corresponding to the gate signal and the number of gradations of the drive gradation data of the four colors red, green, blue and white. a power supply unit 19 for generating a voltage, a controller 20 for controlling the scanning driver circuit 16 and the data driving circuit 17 and the arithmetic unit 18, are made of.

前記映像信号は、表示する画像に対応した同期信号と、1つの表示要素それぞれに対応した表示色を定義する赤、緑、青の3色の階調データとを含む信号であり、前記コントローラ20に入力される。前記コントローラ20は、前記映像信号から、前記同期信号等を分離して前記走査駆動回路16とデータ駆動回路17とに供給し、また前記赤、緑、青の3色の階調データを前記演算部18に供給し、これらの回路の動作を制御する。 Said video signal includes a synchronization signal corresponding to an image to be displayed, a signal containing a red to define a display color corresponding to the respective one of the display elements, green, three-color gradation data of the blue, the controller 20 is input. The controller 20 separates the synchronization signal and the like from the video signal and supplies them to the scan drive circuit 16 and the data drive circuit 17, and also calculates the gradation data of the three colors red, green and blue. The circuit 18 is supplied to control the operation of these circuits.

前記演算部18は、前記コントローラ20から入力された赤、緑、青の3色の階調データに基づいて、予め定めた演算手順に従った演算により、前記液晶表示素子1の複数の表示要素14毎の赤、緑、青及び白の4色の駆動階調データを生成し、その赤、緑、青及び白の4色の駆動階調データを前記データ駆動回路17に供給する。   The calculation unit 18 performs a plurality of display elements of the liquid crystal display element 1 by calculation according to a predetermined calculation procedure based on gradation data of three colors of red, green, and blue input from the controller 20. The drive gradation data of four colors of red, green, blue and white for every 14 are generated, and the drive gradation data of four colors of red, green, blue and white are supplied to the data drive circuit 17.

そして、前記走査駆動回路16は、前記電源部19により発生された電圧値のゲート信号を、前記コントローラ20からの同期信号に対応して前記液晶表示素子1の複数の走査線に順次供給する、前記データ駆動回路17は、前記演算部18からの前記赤、緑、青及び白の4色の駆動階調データにそれぞれ対応した電圧を前記電源部19から選択し、これらの電圧値の赤、緑、青及び白の4色のデータ信号を、同期信号に対応させて前記液晶表示素子1の複数のデータ線に供給する。   The scan driving circuit 16 sequentially supplies a gate signal having a voltage value generated by the power supply unit 19 to a plurality of scanning lines of the liquid crystal display element 1 in accordance with a synchronization signal from the controller 20. The data driving circuit 17 selects voltages corresponding to the drive gradation data of the four colors red, green, blue and white from the arithmetic unit 18 from the power supply unit 19, and red, Data signals of four colors of green, blue and white are supplied to the plurality of data lines of the liquid crystal display element 1 in correspondence with the synchronization signal.

すなわち、前記駆動手段15は、前記液晶表示素子1の複数の画素行を、前記複数の走査線へのゲート信号の供給により順次選択し、選択行の各画素13R,13G,13B,13Wの画素電極5に、前記演算部18において生成された前記複数の表示要素14毎の赤、緑、青及び白の4色の駆動階調データにそれぞれ対応した前記4色のデータ信号を前記複数の信号線及びTFTを介して供給する。   That is, the driving unit 15 sequentially selects a plurality of pixel rows of the liquid crystal display element 1 by supplying gate signals to the plurality of scanning lines, and pixels of the pixels 13R, 13G, 13B, and 13W in the selected row. The four color data signals corresponding to the drive gradation data of four colors of red, green, blue and white for each of the plurality of display elements 14 generated in the calculation unit 18 are applied to the electrode 5. Supply through line and TFT.

前記赤、緑、青及び白の4色の駆動階調データは、前記演算部18において、前記入力された赤、緑、青の3色の階調データに基づいて、以下のように演算することによって得ることができる。   The driving gradation data of the four colors red, green, blue and white are calculated in the calculation unit 18 as follows based on the input gradation data of the three colors red, green and blue. Can be obtained.

すなわち、前記複数の表示要素14毎の前記赤、緑、青及び白の4色の画素13R,13G,13B,13Wそれぞれの最大階調輝度に対するこれらの画素13R,13G,13B,13Wを駆動するための前記駆動階調データに対応する輝度の割合を輝度率、前記複数の表示要素14毎の前記赤、緑、青の3色の画素13R,13G,13B相互の前記輝度率の差の絶対値のうちの最大値を最大輝度率差とするとき、前記複数の表示要素14毎の赤、緑、青及び白の4色の画素13R,13G,13B,13Wの前記輝度率がそれぞれ、前記赤、緑、青の3色の画素13R,13G,13Bそれぞれの前記輝度率に、前記白色画素13Wの特性に応じて予め定めた任意の値の設定輝度率の前記最大輝度率差に相当する階調数以外の階調数に対応する割合の輝度率を加算し、その加算値から前記白色画素13Wの前記輝度率を差し引いた値になるように、前記4色の駆動階調データが定められる。   That is, the pixels 13R, 13G, 13B, and 13W corresponding to the maximum gradation luminance of the four colors of the pixels 13R, 13G, 13B, and 13W for each of the plurality of display elements 14 are driven. The luminance ratio corresponding to the driving gradation data is the luminance ratio, and the difference between the luminance ratios of the red, green, and blue pixels 13R, 13G, and 13B for each of the plurality of display elements 14 is absolute. When the maximum value among the values is the maximum luminance rate difference, the luminance rates of the four colors of pixels 13R, 13G, 13B, and 13W for each of the plurality of display elements 14 are The luminance ratio of each of the red, green, and blue pixels 13R, 13G, and 13B corresponds to the maximum luminance ratio difference of a set luminance ratio that is predetermined in accordance with the characteristics of the white pixel 13W. Tones other than the number of tones Adding the luminance factor of the rate of response, as from the added value becomes a value the less the luminance ratio of the white pixel 13W, the four-color driving gradation data is determined.

ここで、前記赤、緑、青及び白の4色の画素13R,13G,13B,13Wの最大階調輝度は、これらの画素13R,13G,13B,13Wにそれぞれ最大階調値の階調データ(例えば入力された赤、緑、青の3色の階調データがそれぞれ階調値が0〜63の64段階のデータであるときは、階調値が63の階調データ)に対応したデータ信号を供給したときの出射光の強度である。   Here, the maximum gradation luminance of the four colors 13R, 13G, 13B, and 13W of red, green, blue, and white is the gradation data of the maximum gradation value in each of the pixels 13R, 13G, 13B, and 13W. Data corresponding to (for example, input gradation data of three colors of red, green, and blue are 64 steps of data with gradation values of 0 to 63, respectively, gradation data of gradation value 63) This is the intensity of emitted light when a signal is supplied.

この駆動方法は、前記入力された赤、緑、青の3色の階調データから、前記液晶表示素子1の赤、緑、青の3色の画素13R,13G,13B相互の前記輝度率の差と、1フレームにおける全ての表示要素14の前記最大輝度率差に基づいて、前記複数の表示要素14毎の赤、緑、青及び白の4色の駆動階調データの諧調値演算によって求め、これらの諧調値の階調データにそれぞれ対応した前記4色のデータ信号を前記赤、緑、青及び白の4色の画素13R,13G,13B,13Wにそれぞれ供給することにより、前記入力された赤、緑、青の3色の階調データの階調値が互いに異なるときの、前記赤、緑、青の3色の階調データによって定められた色に対する前記表示要素14の表示色の色ずれを低減しようとするものである。   In this driving method, the luminance ratio between the red, green, and blue pixels 13R, 13G, and 13B of the liquid crystal display element 1 is determined from the input red, green, and blue color gradation data. Based on the difference and the maximum luminance rate difference of all the display elements 14 in one frame, it is obtained by calculating gradation values of drive gradation data of red, green, blue and white for each of the plurality of display elements 14. The four color data signals respectively corresponding to the gradation data of the gradation values are supplied to the four color pixels 13R, 13G, 13B, and 13W of red, green, blue, and white, respectively. When the gradation values of the three color data of red, green, and blue are different from each other, the display color of the display element 14 with respect to the color determined by the gradation data of the three colors of red, green, and blue It is intended to reduce color misregistration.

この駆動方法において、前記赤、緑、青及び白の4色の駆動階調データは、前記複数の表示要素14毎に、前記入力された赤、緑、青の3色の階調データの階調値にそれぞれ、前記赤、緑、青の3色の画素13R,13G,13B相互の前記輝度率の差を加算し、さらに前記1フレームにおける全ての表示要素14の前記最大輝度率差に応じて定められる係数を乗じた値のうちの最も小さい値を白の駆動階調データに割り当て、前記入力された赤、緑、青の3色の階調データの階調値からそれぞれ前記白の駆動階調データに割り当てた階調数を差し引いた値をそれぞれ前記赤、緑、青の3色の駆動階調データとする。   In this driving method, the driving gradation data of the four colors red, green, blue, and white is the level of the input gradation data of the three colors red, green, and blue for each of the plurality of display elements 14. The difference between the luminance ratios of the red, green, and blue pixels 13R, 13G, and 13B is added to each of the tone values, and further according to the maximum luminance ratio difference of all the display elements 14 in the one frame. The smallest value among the values obtained by multiplying the coefficient determined by the above is assigned to the white driving gradation data, and the white driving is determined from the gradation values of the inputted three gradation data of red, green and blue. The value obtained by subtracting the number of gradations assigned to the gradation data is set as the drive gradation data for the three colors red, green and blue.

さらに詳述すると、前記入力された赤、緑、青の3色の階調データが、これらの3色相互の階調差が大きいデータ、つまり1つの表示要素14の表示色を濃い色に定めるデータであるときは、前記白色画素13Wの輝度を低くするように前記赤、緑、青及び白の4色の駆動階調データを設定し、前記入力された赤、緑、青の3色の階調データが、これらの3色相互の階調差の小さいデータ、つまり1つの表示要素14の表示色を薄い色に定めるデータであるときは、前記白色画素13Wの輝度を高くするような前記赤、緑、青及び白の4色の駆動階調データを生成する。   More specifically, the inputted gradation data of three colors of red, green, and blue determines data having a large gradation difference between these three colors, that is, the display color of one display element 14 is a dark color. When it is data, the drive gradation data of the four colors of red, green, blue and white is set so as to lower the luminance of the white pixel 13W, and the inputted three colors of red, green and blue are set. When the gradation data is data having a small gradation difference between these three colors, that is, data for determining the display color of one display element 14 to be a light color, the brightness of the white pixel 13W is increased. Drive gradation data of four colors of red, green, blue and white is generated.

前記赤、緑、青及び白の4色の駆動階調データを生成するため、この駆動方法においては、前記複数の表示要素14毎に、前記赤、緑、青の3色の画素13R,13G,13Bそれぞれの前記最大階調輝度に対する前記入力された赤、緑、青の3色の階調データに対応する輝度(入力された赤、緑、青の3色の階調データに対応したデータ信号を供給したときの出射光の強度)の割合である入力データ対応輝度率を求め、さらに、前記複数の表示要素14毎の前記赤、緑、青の3色の画素13R,13G,13B相互の前記入力データ対応輝度率の差の絶対値のうちの最大値を求める。また、前記1フレームにおける全ての表示要素14の最大輝度率差に応じた係数は、例えば、前記全ての表示要素14それぞれの最大輝度率差のうちの最も大きい値に応じて設定する。   In order to generate drive gradation data of the four colors red, green, blue and white, in this drive method, the pixels 13R and 13G of the three colors red, green and blue are provided for each of the plurality of display elements 14. , 13B corresponding to the inputted red, green and blue gradation data for the maximum gradation luminance (data corresponding to the inputted red, green and blue gradation data). The luminance ratio corresponding to the input data, which is the ratio of the intensity of the emitted light when the signal is supplied), is obtained, and the red, green and blue pixels 13R, 13G and 13B for each of the display elements 14 The maximum value of the absolute values of the difference of the luminance ratio corresponding to the input data is obtained. The coefficient corresponding to the maximum luminance rate difference of all the display elements 14 in the one frame is set according to, for example, the largest value among the maximum luminance rate differences of all the display elements 14.

ここで、前記赤、緑、青及び白の4色の画素13R,13G,13B,13Wそれぞれの最大階調輝度をLmaxR,LmaxG,LmaxB,LmaxW、前記赤、緑、青の3色の画素13R,13G,13Bそれぞれの前記入力された赤、緑、青の3色の階調データに対応する輝度を入力データ対応輝度L,L,Lとすると、前記最大階調輝度LmaxR,LmaxG,LmaxB,LmaxWに対する前記入力データ対応輝度L,L,Lの割合である入力データ対応輝度率R,R,Rは、それぞれR=L/LmaxR,R=L/LmaxG,R=L/RmaxBであり、前記3色の画素13R,13G,13B相互の前記入力データ対応輝度率R,R,Rの差の絶対値のうちの最大値最大輝度率差dmaxは、|R−R|,|R−R|,|R−R|のうちの最大値である。 Here, the maximum gradation luminances of the four pixels 13R, 13G, 13B, and 13W of red, green, blue, and white are represented by L maxR , L maxG , L maxB , L maxW , and red, green, and blue, respectively. the color of the pixel 13R, 13G, 13B of red, which is each of the input, green, enter the brightness corresponding to the gradation data of three colors of blue data corresponding luminance L R, L G, when the L B, wherein the maximum gradation luminance L maxR, L maxG, L maxB , wherein for L maxW input data corresponding luminance L R, L G, the input data corresponding luminance factor R R is the ratio of L B, R G, R B are each R R = L R / L maxR , R G = L G / L max G , R B = L B / R max B , and the luminance ratios R R , R G , R corresponding to the input data among the three color pixels 13R, 13G, 13B. B 's The maximum luminance ratio difference d max of the maximum value among the absolute values of the differences is the maximum value of | R R −R G |, | R G −R B |, | R B −R R |.

また、前記1フレームにおける全ての表示要素14それぞれの前記最大輝度率差dmaxのうちの最も大きい値をdmaxALLとすると、このdmaxALLは、前記液晶表示素子1の表示要素数をnとし、前記複数の表示要素14それぞれの赤、緑、青の3色の画素13R,13G,13Bの入力データ対応輝度L,L,Lに前記表示要素14の番号(1)(2)(3),……(n)を付したとき、|RR(1)−RG(1)|,|RG(1)−RB(1)|,|RB(1)−RR(1)|,|RR(2)−RG(2)|,|RG(2)−RB(2)|,|RB(2)−RR(2)|,|RR(3)−RG(3)|,|RG(3)−RB(3)|,|RB(3)−RR(3)|,……|RR(n)−RG(n)|,|RG(n)−RB(n)|,|RB(n)−RR(n)|のうちの最大値である。 Further, assuming that the largest value of the maximum luminance rate differences d max of all the display elements 14 in the one frame is d maxALL , this d maxALL is set to n the number of display elements of the liquid crystal display element 1, wherein the plurality of display elements 14 of each red, green, three-color pixels 13R blue, 13G, input data corresponding brightness L R of 13B, L G, the display element 14 number of the L B (1), (2 ) , (3) , ... When (n) is attached, | R R (1) −R G (1) |, | R G (1) −R B (1) |, | R B (1) − RR (1) |, | RR (2) -RG (2) |, | RG (2) -RB (2) |, | RB (2) -RR (2) |, | R R (3) -R G ( 3) |, | R G (3) -R B (3) |, | R B (3) -R R (3) |, ...... | R R ( ) -R G (n) |, | R G (n) -R B (n) |, | R B (n) -R R (n) | is the maximum value among.

前記1フレームにおける全ての表示要素14それぞれの最大輝度率差dmaxのうちの最も大きい値dmaxALLは、各フレーム毎に、そのフレームの全ての赤、緑、青の3色の階調データをメモリに保存することにより、その保存データに基づいて算出する。 The largest value d maxALL among the maximum luminance rate differences d max of all the display elements 14 in the one frame is the gradation data of all three colors of red, green and blue for each frame. By storing in the memory, calculation is performed based on the stored data.

ただし、フレームレートが1秒間に2フレーム以上の動画表示においては、連続する前後のフレーム相互の赤、緑、青の3色の階調データの類似性が高いため、前のフレームにおける全ての表示要素14それぞれの最大輝度率差dmaxのうちの最も大きい値を、次のフレームのdmaxALLとしてもよく、このようにすることにより、1フレームの全ての赤、緑、青の3色の階調データを保存するためのメモリを省略することができる。 However, when displaying a moving image with a frame rate of 2 frames or more per second, the similarities of the gradation data of the three colors of red, green, and blue between the preceding and succeeding frames are high, so all the displays in the previous frame are displayed. The largest value of the maximum luminance rate difference d max of each element 14 may be set as d maxALL of the next frame, and in this way, all three red, green, and blue levels of one frame are processed. A memory for storing key data can be omitted.

さらに、前記赤、緑、青及び白の4色の画素13R,13G,13B,13Wそれぞれの前記駆動階調データに対応する輝度を駆動データ対応輝度をL′,L′,L′,L′、前記赤、緑、青及び白の4色の画素13R,13G,13B,13Wそれぞれの前記最大階調輝度LmaxR,LmaxG,LmaxB,LmaxWに対する前記駆動データ対応輝度L′,L′,L′,L′の割合L′/LmaxR,L′/LmaxG,L′/LmaxB,L′/LmaxWをそれぞれ駆動データ対応輝度率R′,R′,R′,R′とすると、これらの駆動データ対応輝度率のうちの赤、緑、青の3色の画素13R,13G,13Bの駆動データ対応輝度率R′,R′,R′はそれぞれ、前記表示要素14毎の前記最大輝度率差dmaxに応じて定められる輝度率に、前記1フレームにおける全ての表示要素14の全ての表示要素14それぞれの最大輝度率差dmaxのうちの最も大きい値dmaxALLに応じて定められる係数を乗じた輝度率を、前記それぞれのデータ階調輝度率R,R,Rに加算し、且つ前記白色画素13Wの駆動データ対応輝度率R′を差し引いた値によって表される。 Further, the luminance corresponding to the driving gradation data of each of the red, green, blue, and white pixels 13R, 13G, 13B, and 13W is set to the driving data corresponding luminance L ′ R , L ′ G , and L ′ B. , L ′ W , and the drive data corresponding luminance L for the maximum gradation luminances L maxR , L maxG , L maxB , and L maxW of the four color pixels 13R, 13G, 13B, and 13W of red, green, blue, and white, respectively. ′ R , L ′ G , L ′ B , L ′ W ratio L ′ R / L maxR , L ′ G / L maxG , L ′ B / L maxB , L ′ W / L maxW Assuming that R ′ R , R ′ G , R ′ B and R ′ W , among these driving data corresponding luminance ratios, the driving data corresponding luminance ratio R of the pixels 13R, 13G and 13B of three colors of red, green and blue 'R, R' G, R Each of B, the maximum brightness index difference luminance factor determined according to d max for each of the display elements 14, all the display elements 14 of the respective maximum luminance index difference d max of all display elements 14 in the frame the largest value d luminance factor multiplied by the coefficient determined according to maxALL of out, the respective gray scale luminance factor R R, R G, and added to R B, and the drive data corresponding luminance of the white pixel 13W represented by the value obtained by subtracting the rate R 'W.

ここで、前記白色画素13Wの特性に応じて予め定めた任意の値の設定輝度率をtとすると、前記表示要素14毎の前記最大輝度率差dmaxに対応する輝度率は、0〜LmaxW/(LmaxR+LmaxG+LmaxB)の範囲で、前記白色画素13Wの特性に応じて予め定めた任意の値の設定輝度率tに、前記入力データ対応輝度率R,R,Rの全階調数のうちの前記最大輝度率差dmaxの階調数に対応する階調数を除いた他の階調数を乗じ、さらに前記入力データ対応輝度率R,R,Rを乗じた値、すなわち前記入力データ対応輝度率R,R,Rの全階調数のうちの前記最大輝度率差dmaxの階調数に対応する階調数を除いた他の階調数に対応する部分に相当する。 Here, if the set luminance factor of any value and t 1 which defines in advance according to the characteristics of the white pixel 13W, the luminance ratio corresponding to the maximum brightness index difference d max for each of the display elements 14, 0 L maxW / in the range of (L maxR + L maxG + L maxB), the white setting luminance factor t 1 of any of the values predetermined according to the characteristics of the pixel 13W, the input data corresponding luminance factor R R, R G, multiplied by the other gradation number excluding the number of gradations corresponding to the gradation number of the maximum brightness index difference d max of the whole grayscale number of R B, further wherein the input data corresponding luminance factor R R, R G , a value obtained by multiplying the R B, i.e. the input data corresponding luminance factor R R, R G, the number of gradations corresponding to the gradation number of the maximum brightness index difference d max of the whole grayscale number R B except It corresponds to a portion corresponding to another number of gradations.

さらに、前記1フレームにおける全ての表示要素14の全ての表示要素14それぞれの最大輝度率差dmaxのうちの最も大きい値dmaxALLに応じて定められる係数をtとすると、この係数tは、1/[{1+t(1−dmaxALL)}dmaxALL]で表される値と、{1+LmaxW/(LmaxR+LmaxG+LmaxB)}/(1+t1)で表される値とのうちの小さい方の値である。 Furthermore, when a coefficient determined according to the largest value d maxALL of the maximum luminance rate difference d max of all the display elements 14 of all the display elements 14 in the one frame is t 2 , the coefficient t 2 is , 1 / [{1 + t 1 (1-d maxALL )} d maxALL ], a value represented by {1 + L maxW / (L maxR + L maxG + L maxB )} / (1 + t1) , Is the smaller of the two values.

また、前記表示要素14毎の白色画素13Wの輝度率は、同じ表示要素14の赤、緑、青の3色の画素13R,13G,13Bそれぞれの最大階調輝度LmaxR,LmaxG,LmaxBの和に対する前記白色画素13Wの最大階調輝度LmaxWの割合に、この白色画素13Wの駆動データ対応輝度率R′を乗じた値で表される。 The luminance ratio of the white pixel 13W for each display element 14 is the maximum gradation luminance L maxR , L maxG , L maxB of each of the three color pixels 13R, 13G, 13B of the same display element 14. Is expressed by a value obtained by multiplying the ratio of the maximum gradation luminance L maxW of the white pixel 13W with respect to the sum of the white pixel 13W by the luminance ratio R ′ W corresponding to the drive data of the white pixel 13W.

そこで、この駆動方法においては、前記入力された赤、緑、青の3色の階調データに基づいて、
上述したように前記赤、緑、青及び白の4色の画素13R,13G,13B,13Wそれぞれの最大階調輝度をLmaxR,LmaxG,LmaxB,LmaxW
前記赤、緑、青の3色の画素13R,13G,13Bそれぞれの前記入力された赤、緑、青の3色の階調データに対応する輝度を入力データ対応輝度L,L,L
前記赤、緑、青の3色の画素13R,13G,13Bそれぞれの前記最大階調輝度LmaxR,LmaxG,LmaxBに対する前記入力データ対応輝度L,L,Lの割合L/LmaxR,L/LmaxG,L maxBをそれぞれ入力データ対応輝度率R,R,R
前記複数の表示要素14毎の前記赤、緑、青の3色の画素13R,13G,13B相互の前記入力データ対応輝度率R,R,Rの差の絶対値|R−R|,|R−R|,|R−R|のうちの最大値を最大輝度率差dmax
1画面のカラー画像を表示するための1フレームにおける全ての表示要素14それぞれの前記最大輝度率差dmaxのうちの最も大きい値をdmaxALL
前記赤、緑、青及び白の4色の画素13R,13G,13B,13Wそれぞれのこれらの画素を駆動するための駆動階調データに対応する輝度を駆動データ対応輝度L′,L′,L′,L′
前記赤、緑、青及び白の4色の画素13R,13G,13B,13Wそれぞれの前記最大階調輝度LmaxR,LmaxG,LmaxB,LmaxWに対する前記駆動データ対応輝度L′,L′,L′,L′の割合L′/LmaxR,L′/LmaxG,L′/LmaxB,L′/LmaxWをそれぞれ駆動データ対応輝度率R′,R′,R′,R′とするとき、
前記駆動データ対応輝度率R′,R′,R′,R′が、
R′=R{1+t(1−dmax)}t−R′・LmaxW/(LmaxR+LmaxG+LmaxB
R′=R{1+t(1−dmax)}t−R′・LmaxW/(LmaxR+LmaxG+LmaxB
R′=R{1+t(1−dmax)}t−R′・LmaxW/(LmaxR+LmaxG+LmaxB
ただし、
は、0≦t≦LmaxW/(LmaxR+LmaxG+LmaxB)の範囲の任意の設定値、
は、1/[{1+t(1−dmaxALL)}dmaxALL]≦{1+LmaxW/(LmaxR+LmaxG+LmaxB)}/(1+t)のとき、
=1/[{1+t(1−dmaxALL)}dmaxALL]に設定され、
{1+LmaxW/(LmaxR+LmaxG+LmaxB)}/(1+t)<1/[{1+t(1−dmaxALL)}dmaxALL]のとき、
={1+LmaxW/(LmaxR+LmaxG+LmaxB)}/(1+t)に設定される係数、
を満足する階調値に設定された前記複数の表示要素14毎の赤、緑、青及び白の4色の駆動階調データを生成する。
Therefore, in this driving method, based on the input gradation data of the three colors of red, green, and blue,
As described above, the maximum gradation luminances of the four colors 13R, 13G, 13B, and 13W of red, green, blue, and white are expressed as L maxR , L maxG , L maxB , L maxW ,
The red, green, three-color pixels 13R blue, 13G, 13B of red, which is of each of the input, green, input data corresponding luminance brightness corresponding to the gradation data of three colors of blue L R, L G, L B ,
The red, green, three-color pixels 13R blue, 13G, 13B of each of the maximum gradation luminance L maxR, L MaxG, the input data corresponding luminance to L maxB L R, L G, the proportion of L B L R / L maxR , L G / L maxG , and L B / L maxB are set as input data corresponding luminance rates R R , R G , R B , respectively.
The red for each of the plurality of display elements 14, green, three-color pixels 13R blue, 13G, the input data corresponding luminance factor of 13B mutual R R, R G, the absolute value of the difference between R B | R R -R G |, | R G -R B |, | R B -R R | is the maximum luminance ratio difference d max ,
The largest value of the maximum luminance rate differences d max of all the display elements 14 in one frame for displaying a color image of one screen is represented by d maxALL ,
The luminance corresponding to the driving gradation data for driving each of the pixels 13R, 13G, 13B, 13W of the four colors of red, green, blue, and white is represented by driving data corresponding luminance L ′ R , L ′ G. , L ′ B , L ′ W ,
Luminance L ′ R , L ′ corresponding to the drive data with respect to the maximum gradation luminances L maxR , L maxG , L maxB , L maxW of the four pixels 13R, 13G, 13B, 13W of red, green, blue and white, respectively. G, L 'B, L' W ratio L 'R / L maxR, L ' of the G / L maxG, L 'B / L maxB, L' W / L maxW each drive data corresponding luminance factor R 'R, R ′ G , R ′ B , R ′ W
The drive data-corresponding luminance ratios R ′ R , R ′ G , R ′ B , R ′ W are
R ′ R = R R {1 + t 1 (1−d max )} t 2 −R ′ W · L maxW / (L maxR + L maxG + L maxB )
R ′ G = R G {1 + t 1 (1−d max )} t 2 −R ′ W · L maxW / (L maxR + L maxG + L maxB )
R ′ B = R B {1 + t 1 (1−d max )} t 2 −R ′ W · L maxW / (L maxR + L maxG + L maxB )
However,
t 1 is an arbitrary set value in a range of 0 ≦ t 1 ≦ L maxW / (L maxR + L maxG + L maxB ),
t 2 is 1 / [{1 + t 1 (1−d maxALL )} d maxALL ] ≦ {1 + L maxW / (L maxR + L maxG + L maxB )} / (1 + t 1 )
t 2 = 1 / [{1 + t 1 (1-d maxALL )} d maxALL ],
{1 + L maxW / (L maxR + L maxG + L maxB )} / (1 + t 1 ) <1 / [{1 + t 1 (1−d maxALL )} d maxALL ]
t 2 = {1 + L maxW / (L maxR + L maxG + L maxB )} / (1 + t 1 )
Drive gradation data of four colors of red, green, blue and white for each of the plurality of display elements 14 set to a gradation value satisfying the above is generated.

より具体的には、前記液晶表示素子1が、赤、緑、青及び白の4色の画素13R,13G,13B,13Wそれぞれの輝度がこれらの画素を駆動するための駆動階調データの階調値に比例する特性を有している場合、これらの画素13R,13G,13B,13Wの輝度は前記駆動階調データの階調値として扱うことができ、上記の条件は、下記のように表すことができる。   More specifically, the liquid crystal display element 1 has a gradation of drive gradation data for driving the pixels 13R, 13G, 13B, and 13W of four colors of red, green, blue, and white, respectively. When having a characteristic proportional to the tone value, the luminance of these pixels 13R, 13G, 13B, and 13W can be handled as the tone value of the drive tone data, and the above condition is as follows: Can be represented.

すなわち、前記複数の表示要素14毎の赤、緑、青及び白の4色の駆動階調データは、
入力された赤、緑、青の3色の階調データの階調値をD,D,D、前記赤、緑、青及び白の4色の駆動階調データの階調値をD′,D′,D′,D′とするとき、
D′はD{1+t(1−dmax)}t−Cを整数化した値
D′はD{1+t(1−dmax)}t−Cを整数化した値
D′はD{1+t(1−dmax)}t−Cを整数化した値
D′はCを整数化した値
ただし、Cは、D{1+t(1−dmax)}t,D{1+t(1−dmax)}t,D{1+t(1−dmax)}tのうちの最も小さい値をD2minとするとき、前記D2minが最大階調未満の場合はその値D2minを整数化した値、前記D2minが最大階調以上の場合は前記最大階調の値とする、
の諧調値にそれぞれ設定される。
That is, drive gradation data of four colors of red, green, blue and white for each of the plurality of display elements 14 is
The gradation values of the input red, green, and blue color gradation data are the D R , D G , D B , and the red, green, blue, and white driving gradation data gradation values. When D ′ R , D ′ G , D ′ B , and D ′ W ,
D ′ R is a value obtained by converting D R {1 + t 1 (1−d max )} t 2 −C into an integer D ′ G is a value obtained by converting D G {1 + t 1 (1−d max )} t 2 −C into an integer D ′ B is a value obtained by converting D B {1 + t 1 (1−d max )} t 2 −C into an integer D ′ W is a value obtained by converting C to an integer, where C is D R {1 + t 1 (1−d max )} t 2, D G { 1 + t 1 (1-d max)} t 2, when the smallest value among D B {1 + t 1 ( 1-d max)} t 2 and D 2min, the D 2min If is less than the maximum gradation value obtained by rounding the value D 2min, the D 2min is equal to or larger than the maximum gradation and the value of the maximum gradation,
Is set to each of the gradation values.

なお、前記D′,D′,D′,D′の値は、小数点以下の値の四捨五入による整数化値が好ましいが、整数化は、他の手段、例えば小数点以下の値の切り捨てまたは切り上げ等によってもよい。 The values of D ′ R , D ′ G , D ′ B and D ′ R are preferably integer values obtained by rounding off values after the decimal point. It may be rounded down or rounded up.

このように、この駆動方法は、前記入力された赤、緑、青の3色の階調データに基づいて、前記複数の表示要素14毎の赤、緑、青及び白の4色の画素13R,13G,13B,13Wの駆動データ対応輝度率R′,R′,R′,R′がそれぞれ、前記赤、緑、青の3色の画素13R,13G,13Bそれぞれの駆動データ対応輝度率R′,R′,R′に、前記白色画素13Wの特性に応じて予め定めた任意の値の設定輝度率tの前記最大輝度率差dmaxに相当する階調数以外の階調数に対応する割合の輝度率を加算して得られる値に、1フレームにおける全ての表示要素14それぞれの前記最大輝度率差dmaxのうちの最も大きい値dmaxALLに応じて設定される係数を乗じ、且つ前記白色画素13Wの駆動データ対応輝度率R′を差し引いた値となるように、前記複数の表示要素14毎の赤、緑、青及び白の4色の階調データを設定し、これらの駆動階調データにそれぞれ対応した前記4色のデータ信号を前記複数の表示要素14の赤、緑、青及び白の4色の画素13R,13G,13B,13Wにそれぞれ供給するようにしたものである。 In this way, this driving method is based on the input three-color gradation data of red, green, and blue, and the four-color pixels 13R of red, green, blue, and white for each of the plurality of display elements 14. , 13G, 13B, and 13W corresponding to the drive data luminance ratios R ′ R , R ′ G , R ′ B , and R ′ W are the drive data for the red, green, and blue pixels 13R, 13G, and 13B, respectively. The corresponding luminance rates R ′ R , R ′ G and R ′ B are gradations corresponding to the maximum luminance rate difference d max of the set luminance rate t 1 having an arbitrary value determined in advance according to the characteristics of the white pixel 13W. In accordance with the maximum value d maxALL of the maximum luminance ratio differences d max of all the display elements 14 in one frame, to a value obtained by adding the luminance ratio of a ratio corresponding to the number of gradations other than the number Multiply by the set coefficient and the white pixel 13W The gradation data of four colors of red, green, blue and white for each of the plurality of display elements 14 is set so as to be a value obtained by subtracting the luminance ratio R ′ W corresponding to the driving data of the driving data. The four color data signals respectively corresponding to 4 are supplied to the red, green, blue and white pixels 13R, 13G, 13B and 13W of the plurality of display elements 14, respectively.

この駆動方法によれば、赤、緑、青及び白の4色の画素13R,13G,13B,13Wにより1つの表示要素14を構成した前記液晶表示素子1に、入力された三原色の階調データに対応した色再現性の良いカラー画像を表示させることができる。   According to this driving method, the gradation data of the three primary colors input to the liquid crystal display element 1 in which one display element 14 is constituted by the four color pixels 13R, 13G, 13B, and 13W of red, green, blue, and white. A color image with good color reproducibility corresponding to can be displayed.

このように本駆動方法は、前記入力された赤、緑、青の3色の階調データに基づいて、前記複数の表示要素14毎の赤、緑、青及び白の4色の画素13R,13G,13B,13Wの駆動データ対応輝度率R′,R′,R′,R′がそれぞれ、前記赤、緑、青の3色の画素13R,13G,13Bそれぞれの駆動データ対応輝度率R′,R′,R′に、前記白色画素13Wの特性に応じて予め定めた任意の値の設定輝度率tの前記最大輝度率差dmaxに相当する階調数以外の階調数に対応する割合の輝度率を加算して得られる値に、1画面のカラー画像を表示するための1フレームにおける全ての表示要素14の前記最大輝度率差dmaxに応じて定められる係数を乗じ、且つ前記白色画素13Wの駆動データ対応輝度率R′を差し引いた値となるように、前記複数の表示要素14毎の赤、緑、青び白の4色の階調データの諧調値を定めているため、前記先願の駆動方法に比べて、白表示の輝度をさらに高くすることができる。 In this way, the present driving method is based on the input three-color gradation data of red, green, and blue, and the red, green, blue, and white pixels 13R, The luminance ratios R ′ R , R ′ G , R ′ B , and R ′ W corresponding to the drive data of 13G, 13B, and 13W correspond to the drive data of the pixels 13R, 13G, and 13B of the three colors of red, green, and blue, respectively. The number of gradations corresponding to the maximum luminance rate difference d max of the set luminance rate t 1 of an arbitrary value determined in advance according to the characteristics of the white pixel 13 W to the luminance rates R ′ R , R ′ G and R ′ B In accordance with the maximum luminance rate difference d max of all the display elements 14 in one frame for displaying a color image of one screen to a value obtained by adding a luminance rate of a ratio corresponding to the number of gradations other than Drive data of the white pixel 13W by multiplying by a predetermined coefficient As a value obtained by subtracting the応輝degree ratio R 'W, red for each of the plurality of display elements 14, green, since defining an gradation value of the gradation data of four colors of blue whitening, JP-A-2005-303681 Compared with this driving method, the brightness of white display can be further increased.

すなわち、前記液晶表示素子1が、赤、緑、青及び白の4色の画素13R,13G,13B,13Wそれぞれの輝度がこれらの画素13R,13G,13B,13Wを駆動するための駆動階調データの階調値に比例する特性を有している場合、前記入力された赤、緑、青の3色の階調データがそれぞれ、例えば階調値が0〜63の64段階のデータであるとすると、前記赤、緑、青及び白の4色の画素13R,13G,13B,13Wそれぞれの最大階調輝度(階調値が63の階調データに対応したデータ信号を供給したときの輝度)LmaxR,LmaxG,LmaxB,LmaxWは、
maxR=22cd/m
maxG=62cd/m
maxB=16cd/m
maxW=100cd/m
である。
That is, in the liquid crystal display element 1, the luminance of each of the four colors 13R, 13G, 13B, and 13W of red, green, blue, and white is driven to drive the pixels 13R, 13G, 13B, and 13W. When the data has a characteristic proportional to the gradation value of the data, the inputted gradation data of the three colors of red, green, and blue are, for example, 64 levels of data with gradation values of 0 to 63, for example. Then, the maximum gradation luminance of each of the red, green, blue and white pixels 13R, 13G, 13B and 13W (luminance when a data signal corresponding to gradation data having a gradation value of 63 is supplied) ) L maxR , L maxG , L maxB , L maxW are
L maxR = 22 cd / m 2
L maxG = 62 cd / m 2
L maxB = 16 cd / m 2
L maxW = 100 cd / m 2
It is.

図7は前記液晶表示素子1の赤、緑、青及び白の4色の画素13R,13G,13B,13Wにそれぞれ前記最大階調の階調データに対応したデータ信号を供給したときの各色の画素13R,13G,13B,13Wから出射する赤、緑、青及び白の4色の光の分光特性を示している。   FIG. 7 shows the respective colors when data signals corresponding to the gradation data of the maximum gradation are supplied to the four color pixels 13R, 13G, 13B, and 13W of red, green, blue and white of the liquid crystal display element 1, respectively. The spectral characteristics of light of four colors of red, green, blue and white emitted from the pixels 13R, 13G, 13B and 13W are shown.

前記赤、緑、青の3色の画素13R,13G,13Bの入力データ対応輝度率R,R,R(R=L/LmaxR,R=L/LmaxG,R=L/RmaxB)は、前記液晶表示素子1の赤、緑、青及び白の4色の画素13R,13G,13B,13Wそれぞれの輝度がこれらの画素13R,13G,13B,13Wを駆動するための駆動階調データの階調値に比例する場合、R=L/63,R=L/63,R=L/63で表せる。 The luminance ratios R R , R G , R B (R R = L R / L maxR , R G = L G / L maxG , R) of the red, green and blue pixels 13R, 13G, 13B B = L B / R maxB ) means that the luminance of the four colors 13R, 13G, 13B, and 13W of the red, green, blue, and white of the liquid crystal display element 1 is determined by the pixels 13R, 13G, 13B, and 13W. When proportional to the gradation value of the drive gradation data for driving, it can be expressed by R R = L R / 63, R G = L G / 63, and R B = L B / 63.

また、前記1つの表示要素14を構成する赤、緑、青及び白の4色の画素13R,13G,13B,13Wのうちの1色の画素に階調値が63の階調データに対応するデータ信号を供給し、他の3色の画素に階調値が0の階調データに対応するデータ信号を供給したときの前記表示要素14の表示の色度x,y(xコーディネイト値とyコーディネイト値)は、
赤色画素13Rに階調値が63の階調データに対応したデータ信号を供給し、他の色の画素13G,13B,13Wに階調値が0の階調データに対応したデータ信号を供給したとき、x=0.56,y=0.36
緑色画素13Gに階調値が63の階調データに対応したデータ信号を供給し、他の色の画素13R,13B,13Wに階調値が0の階調データに対応したデータ信号を供給したとき、x=0.34,y=0.54
青色画素13Bに階調値が63の階調データに対応したデータ信号を供給し、他の色の画素13R,13G,13Wに階調値が0の階調データに対応したデータ信号を供給したとき、x=0.16,y=0.13
白色画素13Wに階調値が63の階調データに対応したデータ信号を供給し、他の色の画素13R,13G,13Bに階調値が0の階調データに対応したデータ信号を供給したとき、x=0.31,y=0.32
である。
Further, one of the four pixels 13R, 13G, 13B, and 13W of red, green, blue, and white constituting the one display element 14 corresponds to gradation data having a gradation value of 63. The display element 14 display chromaticity x, y (x coordinate value and y) when the data signal is supplied and the data signal corresponding to the gradation data of gradation value 0 is supplied to the other three color pixels. coordinate value) is,
A data signal corresponding to gradation data having a gradation value of 63 was supplied to the red pixel 13R, and a data signal corresponding to gradation data having a gradation value of 0 was supplied to the pixels 13G, 13B, and 13W of the other colors. When x = 0.56, y = 0.36
A data signal corresponding to gradation data having a gradation value of 63 was supplied to the green pixel 13G, and a data signal corresponding to gradation data having a gradation value of 0 was supplied to the pixels 13R, 13B, and 13W of the other colors. When x = 0.34, y = 0.54
A data signal corresponding to gradation data having a gradation value of 63 was supplied to the blue pixel 13B, and a data signal corresponding to gradation data having a gradation value of 0 was supplied to the pixels 13R, 13G, and 13W of other colors. When x = 0.16, y = 0.13
A data signal corresponding to gradation data having a gradation value of 63 was supplied to the white pixel 13W, and a data signal corresponding to gradation data having a gradation value of 0 was supplied to the pixels 13R, 13G, and 13B of other colors. When x = 0.31, y = 0.32.
It is.

比較例としての駆動方法を例示する。この比較例の駆動方法は、入力された赤、緑、青の3色の階調データの階調値をD,D,D、赤、緑、青及び白の4色の駆動階調データの階調値D′,D′,D′,D′を、
D′=D{1+t(1−dmax)}−Cの整数化値
D′=D{1+t(1−dmax)}−Cの整数化値
D′=D{1+t(1−dmax)}−Cの整数化値
D′=Cの整数化値
ただし、係数Cは、入力された赤、緑、青の3色の階調データの最大階調値が63である場合、前記D{1+t(1−dmax)},D{1+t(1−dmax)},D{1+t(1−dmax)}のうちの最も小さい値Dminが63未満であるときはC=Dminとし、前記値Dminが63以上のときはC=63とする、の条件を満たす諧調値にそれぞれ設定された4色の駆動階調データを生成するのである。
The drive method as a comparative example is illustrated. In the driving method of this comparative example, the gradation values of the input gradation data of three colors of red, green, and blue are converted into driving gradations of four colors of D R , D G , D B , red, green, blue, and white. The tone values D ' R , D' G , D ' B , D' W of the tone data are
D ′ R = D R {1 + t (1−d max )} − C integerized value D ′ G = D G {1 + t (1−d max )} − C integerized value D ′ B = D B {1 + t (1-d max)} - integer value of integer values D 'W = C of C, however, the engagement number C is red with the input green, maximum tone value of the gradation data of three colors of blue 63, the smallest value D min among the D R {1 + t (1−d max )}, D G {1 + t (1−d max )}, D B {1 + t (1−d max )} Since the drive gradation data of four colors respectively set to the gradation value satisfying the condition of C = D min when the value is less than 63 and C = 63 when the value D min is 63 or more is generated. is there.

それに対して、本駆動方法では、前記赤、緑、青及び白の4色の駆動階調データの階調値D′,D′,D′,D′を、
D′=D{1+t(1−dmax)}t−Cの整数化値
D′=D{1+t(1−dmax)}t−Cの整数化値
D′=D{1+t(1−dmax)}t−Cの整数化値
D′=Cの整数化値
に設定する。
On the other hand, in this driving method, the gradation values D ′ R , D ′ G , D ′ B , and D ′ W of the driving gradation data of the four colors of red, green, blue, and white are expressed as follows:
D ′ R = D R {1 + t 1 (1−d max )} t 2 −C integerized value D ′ G = D G {1 + t 1 (1−d max )} t 2 −C integerized value D ′ B = D B {1 + t 1 (1−d max )} t 2 −C integer value D ′ W = C is set to an integer value.

本駆動方法において、前記入力された赤、緑、青の3色の階調データの最大階調値が63である場合、前記D{1+t(1−dmax)}t,D{1+t(1−dmax)}t,D{1+t(1−dmax)}tのうちの最も小さい値D2minに対応した係数Cは、前記D2minが63未満であるときはC=D2minとし、前記D 2minが63以上のときはC=63とした。 In this driving method, the inputted red, green, when the maximum gradation value of the gradation data of three colors of blue is 63, the D R {1 + t 1 ( 1-d ma x)} t 2, D The coefficient C corresponding to the smallest value D 2min among G {1 + t 1 (1−d max )} t 2 and D B {1 + t 1 (1−d max )} t 2 is less than 63 for D 2min. sometimes is a C = D 2mi n, before Symbol D 2min is when the 63 above was C = 63.

前記比較例の駆動方法による1フレーム中の1つの表示要素14の表示と、本駆動方法による1フレーム中の1つの表示要素14の表示とを比較する。なお、ここでは、先願の駆動方法における前記tの値をt=0.5とし、本駆動方法における前記tとdmaxALLの値をt=0.5、dmaxALL=0.76とした。 Compare Display and one display element 14 in one frame by the driving method of the comparative example, and a display of one display element 14 in one frame according to the driving method. Here, the value of t in the driving method of the prior application is t = 0.5, and the values of t 1 and d maxALL in the driving method are t 1 = 0.5 and d maxALL = 0.76. did.

例えば、前記1つの表示要素14に対する赤、緑、青の3色の階調データが白色を定めたデータであるとき、つまり前記赤、緑、青の3色の階調データの階調値D,D,Dが、D=63,D=63,D=63のときは、
max=63/63−63/63=0
である。
For example, when the gradation data of the three colors red, green, and blue for the one display element 14 is data defining white, that is, the gradation value D of the gradation data of the three colors red, green, and blue. R, D G, is D B, when D R = 63, D G = 63, D B = 63 is
d max = 63 / 63−63 / 63 = 0
It is.

そして、dmax=0のとき、前記比較例の駆動方法では、t=0.5とすると、
{1+t(1−dmax)}=63{1+0.5(1−0)}=94.50
{1+t(1−dmax)}=63{1+0.5(1−0)}=94.50
{1+t(1−dmax)}=63{1+0.5(1−0)}=94.50
min=94.50
C=63
であり、
{1+t(1−dmax}−C=94.50−63=31.50
{1+t(1−dmax}−C=94.50−63=31.50
{1+t(1−dmax}−C=94.50−63=31.50
となるため、
D′=32
D′=32
D′=32
D′=32
となり、輝度が151cd/m2の白表示が得られる。
When d max = 0, in the driving method of the comparative example, if t = 0.5,
D R {1+ t (1- d max)} = 63 {1 + 0.5 (1-0)} = 94.50
D G {1+ t (1- d max)} = 63 {1 + 0.5 (1-0)} = 94.50
D B {1+ t (1- d max)} = 63 {1 + 0.5 (1-0)} = 94.50
D min = 94.50
C = 63
And
D R {1+ t (1- d max)} - C = 94.50-63 = 31.50
D G {1+ t (1- d max)} - C = 94.50-63 = 31.50
D B {1+ t (1- d max)} - C = 94.50-63 = 31.50
So that
D ′ R = 32
D ′ G = 32
D ′ B = 32
D ′ W = 32
Thus, a white display with a luminance of 151 cd / m 2 is obtained.

これに対して本駆動方法では、t=0.5、dmaxALL=0.76とすると、
1/[{1+t(1−dmaxALL)}dmaxALL
=1/[{1+0.5(1−0.76)}0.76]=1.17
{1+LmaxW/(LmaxR+LmaxG+LmaxB)}/(1+t
=(1+1)/(1+0.5)=1.33
であり、したがって、
1/[{1+t(1−dmaxALL)}dmaxALL
≦{1+LmaxW/(LmaxR+LmaxG+LmaxB)}/(1+t
であるため、
=1/[{1+t(1−dmaxALL)}dmaxALL]=1.17
になる。
On the other hand, in this driving method, when t 1 = 0.5 and d maxALL = 0.76,
1 / [{1 + t 1 (1−d maxALL )} d maxALL ]
= 1 / [{1 + 0.5 (1-0.76)} 0.76] = 1.17
{1 + L maxW / (L maxR + L maxG + L maxB )} / (1 + t 1 )
= (1 + 1) / (1 + 0.5) = 1.33
And therefore
1 / [{1 + t 1 (1−d maxALL )} d maxALL ]
≦ {1 + L maxW / (L maxR + L maxG + L maxB )} / (1 + t 1 )
Because
t 2 = 1 / [{1 + t 1 (1-d maxALL)} d maxALL] = 1.17
become.

そして、dmax=0のときは、
{1+t(1−dmax)}t
=63{1+0.5(1−0)}1.17=110.84
{1+t(1−dmax)}t
=63{1+0.5(1−0)}1.17=110.84
{1+t(1−dmax)}t
=63{1+0.5(1−0)}1.17=110.84
2min=110.84
C=63
であり、
D′=D{1+t(1−dmax)}t−C=110.8−63=47.84
D′=D{1+t(1−dmax)}t−C=110.8−63=47.84
D′=D{1+t(1−dmax)}t−C=110.8−63=47.84
となるため、
D′=48
D′=48
D′=48
D′=63
となり、輝度が176cd/mの白表示が得られる。
And when d max = 0,
D R {1 + t 1 (1-d max )} t 2
= 63 {1 + 0.5 (1-0)} 1.17 = 1100.84
D G {1 + t 1 (1−d max )} t 2
= 63 {1 + 0.5 (1-0)} 1.17 = 1100.84
D B {1 + t 1 (1−d max )} t 2
= 63 {1 + 0.5 (1-0)} 1.17 = 1100.84
D 2min = 110.84
C = 63
And
D ′ R = D R {1 + t 1 (1−d max )} t 2 −C = 110.8−63 = 47.84
D ′ G = D G {1 + t 1 (1−d max )} t 2 −C = 110.8−63 = 47.84
D ′ B = D B {1 + t 1 (1−d max )} t 2 −C = 110.8−63 = 47.84
So that
D ′ R = 48
D ′ G = 48
D ′ B = 48
D ′ W = 63
Thus, a white display with a luminance of 176 cd / m 2 is obtained.

この白表示の輝度(176cd/m)は、前記比較例の駆動方法による白表示の輝度(151cd/m)に比べて25cd/m高い。 The brightness of white display (176 cd / m 2 ) is 25 cd / m 2 higher than the brightness of white display (151 cd / m 2 ) by the driving method of the comparative example.

なお、ここでは赤、緑、青の3色の階調データの階調値D,D,Dがそれぞれ63のときの白表示について説明したが、前記赤、緑、青の3色の階調データの階調値D,D,Dがそれぞれ0のときは黒が表示され、前記階調値D,D,Dがそれぞれ0以上、63未満の範囲の同じ値のときは灰色(白と黒の中間色)が表示される。 Here, red, green, gray-scale value D R of the gradation data of three colors of blue, D G, but D B has been described white display when each 63, the red, green, three colors of blue the gradation value D R of grayscale data, D G, D B appears black when the 0 respectively, the gradation value D R, D G, D B, respectively 0 or more, in the range of less than 63 the same When it is a value, gray (the intermediate color between white and black) is displayed.

また、前記1つの表示要素14に対する赤、緑、青の3色の階調データが、赤、緑、青の3色を互いに異なる比率で混色させた中間色を定めたデータであるとき、例えば前記赤、緑、青の3色の階調データの階調値D,D,Dが、D=55,D=31,D=7のときは、dmax=55/63−7/63=48/63である。 Further, when the gradation data of three colors of red, green, and blue for the one display element 14 is data that defines an intermediate color obtained by mixing the three colors of red, green, and blue at different ratios, for example, red, green, and gray-scale value D R of the gradation data of three colors of blue, D G, is D B, when D R = 55, D G = 31, D B = 7, d max = 55/63 −7 / 63 = 48/63.

そして、dmax=48/63のとき、前記比較例の駆動方法では、t=0.5とすると、
{1+t(1−dmax)}=55{1+0.5(1−48/63)}=61.55
{1+t(1−dmax)}=31{1+0.5(1−48/63)}=34.69
{1+t(1−dmax)}=7{1+0.5(1−48/63)}=7.83
min=7.83
C=7.83
であり、
{1+t(1−dmax}−C=61.55−7.83=53.71
{1+t(1−dmax}−C=34.69−7.83=26.86
{1+t(1−dmax}−C=7.83−7.83=0
となるため、
D′=54
D′=27
D′=0
D′=8
となり、輝度が58cd/m2の中間色表示が得られる。
When d max = 48/63 , in the driving method of the comparative example, if t = 0.5,
D R {1+ t (1- d max)} = 55 {1 + 0.5 (1-48 / 63)} = 61.55
D G {1+ t (1- d max)} = 31 {1 + 0.5 (1-48 / 63)} = 34.69
D B {1+ t (1- d max)} = 7 {1 + 0.5 (1-48 / 63)} = 7.83
D min = 7.83
C = 7.83
And
D R {1+ t (1- d max)} - C = 61.55-7.83 = 53.71
D G {1+ t (1- d max)} - C = 34.69-7.83 = 26.86
D B {1+ t (1- d max)} - C = 7.83-7.83 = 0
So that
D ′ R = 54
D ′ G = 27
D ′ B = 0
D ′ W = 8
Thus, an intermediate color display having a luminance of 58 cd / m 2 is obtained.

この中間色表示の色度は、前記3色画素表示素子における、1つの表示要素の赤、緑、青の3色の画素に、赤、緑、青の階調値がそれぞれ55,31,7の3色の階調データに対応したデータ信号を供給したときの前記表示要素の表示の色度と同じであり、また、この中間色表示の輝度(58cd/m2)は、この比較例の駆動方法による前記白表示の輝度(151cd/m2)の約39%である。 The chromaticity of the intermediate color display is such that red, green, and blue gradation values of 55, 31, and 7 are respectively applied to the three color pixels of red, green, and blue of one display element in the three-color pixel display element. when supplying the three-color data signals corresponding to the grayscale data is the the same as the chromaticity display of display elements, also the gray scale display of the luminance (58cd / m2), the driving method of the comparative example Is about 39% of the luminance (151 cd / m 2) of the white display.

これに対して本駆動方法では、t=0.5、dmaxALL=0.76とすると、上記のようにt=117であるため、dmax=48/63のときは、
{1+t(1−dmax)}t
=55{1+0.5(1−48/63)}1.17=72.19
{1+t(1−dmax)}t
=31{1+0.5(1−48/63)}1.17=40.69
{1+t(1−dmax)}t
=7{1+0.5(1−48/63)}1.17=9.19
2min=9.19
C=9.19
であり、
D′=D{1+t(1−dmax)}t−C=72.19−9.19=63.00
D′=D{1+t(1−dmax)}t−C=40.69−9.19=31.50
D′=D{1+t(1−dmax)}t−C=9.19−9.19=0
となるため、
D′=63
D′=32
D′=0
D′=9
となり、輝度が68cd/m2の中間色表示が得られる。
On the other hand, in this driving method, when t 1 = 0.5 and d maxALL = 0.76, t 2 = 1 . 17 so that d max = 48/63,
D R {1 + t 1 (1-d max )} t 2
= 55 {1 + 0.5 (1-48 / 63)} 1.17 = 72.19
D G {1 + t 1 (1−d max )} t 2
= 31 {1 + 0.5 (1-48 / 63)} 1.17 = 40.69
D B {1 + t 1 (1−d max )} t 2
= 7 {1 + 0.5 (1-48 / 63)} 1.17 = 9.19
D 2min = 9.19
C = 9.19
And
D ′ R = D R {1 + t 1 (1−d max )} t 2 −C = 72.19-9.19 = 63.00
D 'G = D G {1 + t 1 (1-d max)} t 2 -C = 40.69-9.19 = 31.50
D ′ B = D B {1 + t 1 (1−d max )} t 2 −C = 9.19−9.19 = 0
So that
D ′ R = 63
D ′ G = 32
D ′ B = 0
D ′ W = 9
Thus, an intermediate color display having a luminance of 68 cd / m 2 is obtained.

この中間色表示の色度は、前記比較例の駆動方法による色度と同じであり、したがって、前記3色画素表示素子における、1つの表示要素の赤、緑、青の3色の画素に、赤、緑、青の階調値がそれぞれ55,31,7の3色の階調データに対応したデータ信号を供給したときの前記表示要素の表示の色度と同じである。また、この中間色表示の輝度(68cd/m2)は、本駆動方法による前記白表示の輝度(176cd/m2)の約39%であり、前記比較例の駆動方法による前記白表示と中間色表示との輝度比と同等である。 The chromaticity of the intermediate color display is the same as the chromaticity obtained by the driving method of the comparative example. Therefore, the red, green, and blue pixels of one display element in the three-color pixel display element are red. , green, gray scale value of blue the display chromaticity and is the same display elements when supplying the data signal corresponding to the grayscale data of three colors 55,31,7 respectively. Further, the luminance (68 cd / m 2) of the intermediate color display is about 39% of the luminance (176 cd / m 2) of the white display by this driving method, and the white display and the intermediate color display by the driving method of the comparative example are It is equivalent to the luminance ratio.

また、前記1つの表示要素14に対する赤、緑、青の3色の階調データが、他の中間色を定めたデータであるとき、例えば前記赤、緑、青の3色の階調データの階調値D,D,Dが、D=47,D=31,D=15のときは、dmax=47/63−15/63=32/63である。 Further, when the gradation data of the three colors red, green, and blue for the one display element 14 is data that defines another intermediate color, for example, the gradation data of the gradation data of the three colors red, green, and blue is used. tone value D R, D G, D B is, when the D R = 47, D G = 31, D B = 15, is d max = 47 / 63-15 / 63 = 32/63.

そして、dmax=32/63のとき、比較例の駆動方法では、t=0.5とすると、
{1+t(1−dmax)}=47{1+0.5(1−32/63)}=58.56
{1+t(1−dmax)}=31{1+0.5(1−32/63)}=38.63
{1+t(1−dmax)}=15{1+0.5(1−32/63)}=18.69
min=18.69
C=18.69
であり、
{1+t(1−dmax}−C=58.56−18.69=39.87
{1+t(1−dmax}−C=38.63−18.69=19.94
{1+t(1−dmax}−C=18.69−18.69=0
となるため、
D′=40
D′=20
D′=0
D′=19
となり、輝度が64cd/m2の中間色表示が得られる。
When d max = 32/63 , in the driving method of the comparative example, if t = 0.5,
D R {1+ t (1- d max)} = 47 {1 + 0.5 (1-32 / 63)} = 58.56
D G {1+ t (1- d max)} = 31 {1 + 0.5 (1-32 / 63)} = 38.63
D B {1+ t (1- d max)} = 15 {1 + 0.5 (1-32 / 63)} = 18.69
D min = 18.69
C = 18.69
And
D R {1+ t (1- d max)} - C = 58.56-18.69 = 39.87
D G {1+ t (1- d max)} - C = 38.63-18.69 = 19.94
D B {1+ t (1- d max)} - C = 18.69-18.69 = 0
So that
D ′ R = 40
D ′ G = 20
D ′ B = 0
D ′ W = 19
Thus, an intermediate color display having a luminance of 64 cd / m 2 is obtained.

この中間色表示の色度は、前記3色画素表示素子における、1つの表示要素の赤、緑、青の3色の画素に、赤、緑、青の階調値がそれぞれ47,31,15の3色の階調データに対応したデータ信号を供給したときの前記表示要素の表示の色度と同じであり、また、この中間色表示の輝度(64cd/m2)は、この比較例の駆動方法による前記白表示の輝度(151cd/m2)の約42%である。 The chromaticity of the intermediate color display is such that red, green, and blue gradation values of 47, 31, and 15 are respectively applied to three red, green, and blue pixels of one display element in the three-color pixel display element. when supplying the three-color data signals corresponding to the grayscale data is the the same as the chromaticity display of display elements, also the gray scale display of the luminance (64cd / m2), the driving method of the comparative example Is about 42% of the brightness (151 cd / m 2) of the white display.

これに対して本駆動方法では、t=0.5、dmaxALL=0.76とすると、上記のようにt=117であるため、dmax=32/63のときは、
{1+t(1−dmax)}t
=47{1+0.5(1−32/63)}1.17=68.69
{1+t(1−dmax)}t
=31{1+0.5(1−32/63)}1.17=45.30
{1+t(1−dmax)}t
=15{1+0.5(1−32/63)}1.17=21.92
2min=21.92
C=21.92
であり、
D′=D{1+t(1−dmax)}t−C=68.69−21.92=46.77
D′=D{1+t(1−dmax)}t−C=45.30−21.92=23.38
D′=D{1+t(1−dmax)}t−C=21.92−21.92=0
となるため、
D′=47
D′=23
D′=0
D′=22
となり、輝度が74cd/m2の中間色表示が得られる。
On the other hand, in this driving method, when t 1 = 0.5 and d maxALL = 0.76, t 2 = 1 . 17 so that d max = 32/63 ,
D R {1 + t 1 (1-d max )} t 2
= 47 {1 + 0.5 (1-32 / 63)} 1.17 = 68.69
D G {1 + t 1 (1−d max )} t 2
= 31 {1 + 0.5 (1-32 / 63)} 1.17 = 45.30
D B {1 + t 1 (1−d max )} t 2
= 15 {1 + 0.5 (1-32 / 63)} 1.17 = 21.92
D2min = 21.92
C = 21.92
And
D ′ R = D R {1 + t 1 (1−d max )} t 2 −C = 68.69-21.92 = 46.77
D ′ G = D G {1 + t 1 (1−d max )} t 2 −C = 45.30-21.92 = 23.38
D ′ B = D B {1 + t 1 (1−d max )} t 2 −C = 21.92-21.92 = 0
So that
D ′ R = 47
D ′ G = 23
D ′ B = 0
D ′ W = 22
Thus, an intermediate color display with a luminance of 74 cd / m 2 is obtained.

この中間色表示の色度は、前記比較例の駆動方法による色度と同じであり、したがって、前記3色画素表示素子における、1つの表示要素の赤、緑、青の3色の画素に、赤、緑、青の階調値がそれぞれ47,31,15の3色の階調データに対応したデータ信号を供給したときの前記表示要素の表示の色度と同じである。また、この中間色表示の輝度(74cd/m2)は、本駆動方法による前記白表示の輝度(176cd/m2)の約42%であり、前記比較例の駆動方法による赤、緑、青の3色の階調データの階調値D,D,Dが、D=47,D=31,D=15のときの白表示と中間色表示との輝度比と同等である。 The chromaticity of the intermediate color display is the same as the chromaticity obtained by the driving method of the comparative example. Therefore, the red, green, and blue pixels of one display element in the three-color pixel display element are red. , green, gray scale value of blue the display chromaticity and is the same display elements when supplying the data signal corresponding to the grayscale data of three colors of 47,31,15, respectively. Further, the brightness (74 cd / m 2) of the intermediate color display is about 42% of the brightness (176 cd / m 2) of the white display by this driving method, and the three colors of red, green, and blue by the driving method of the comparative example. the gradation value D R of the gradation data, D G, D B is equal to the luminance ratio of the white display and the gray scale display at the time of D R = 47, D G = 31, D B = 15.

また、前記1つの表示要素14に対する赤、緑、青の3色の階調データが、赤、緑、青の3色のうちのいずれか1色の原色を定めたデータであるとき、例えば前記赤、緑、青の3色の階調データの階調値D,D,Dが、D=63,D=0,D=0のときは、dmax=63/63−0/63=1である。 Further, when the gradation data of three colors of red, green, and blue for the one display element 14 is data that defines a primary color of any one of the three colors of red, green, and blue, for example, red, green, and gray-scale value D R of the gradation data of three colors of blue, D G, is D B, when D R = 63, D G = 0, D B = 0, d max = 63/63 −0 / 63 = 1.

そして、dmax=1のとき、前記比較例の駆動方法では、t=0.5とすると、
{1+t(1−dmax)}=63{1+0.5(1−1)}=63.00
{1+t(1−dmax)}=0{1+0.5(1−1)}=0
{1+t(1−dmax)}=0{1+0.5(1−1)}=0
min=0
C=0
であり、
{1+t(1−dmax)}−C=63.00
{1+t(1−dmax)}−C=0
{1+t(1−dmax)}−C=0
となるため、
D′=63
D′=0
D′=0
D′=0
となり、輝度が22cd/m2の赤色の原色表示が得られる。
When d max = 1, in the driving method of the comparative example, if t = 0.5,
D R {1+ t (1- d max)} = 63 {1 + 0.5 (1-1)} = 63.00
D G {1+ t (1- d max)} = 0 {1 + 0.5 (1-1)} = 0
D B {1+ t (1- d max)} = 0 {1 + 0.5 (1-1)} = 0
D min = 0
C = 0
And
D R {1+ t (1- d max)} - C = 63.00
D G {1+ t (1- d max)} - C = 0
D B {1+ t (1- d max)} - C = 0
So that
D ′ R = 63
D ′ G = 0
D ′ B = 0
D ′ W = 0
Thus, a primary color display of red having a luminance of 22 cd / m 2 is obtained.

これに対して本駆動方法では、t=0.5、dmaxALL=1.00とすると、
1/[{1+t(1−dmaxALL)}dmaxALL
=1/[{1+0.5(1−1)}1.00]=.00
{1+LmaxW/(LmaxR+LmaxG+LmaxB)}/(1+t
=(1+1)/(1+0.5)=1.33
であり、したがって、
1/[{1+t(1−dmaxALL)}dmaxALL
≦{1+LmaxW/(LmaxR+LmaxG+LmaxB)}/(1+t
であるため、
=1/[{1+t1(1−dmaxALL)}dmaxALL]=1.00
になる。
On the other hand, in this driving method, when t 1 = 0.5 and d maxALL = 1.00,
1 / [{1 + t 1 (1−d maxALL )} d maxALL ]
= 1 / [{1 + 0.5 (1-1)} 1.00] = 1 . 00
{1 + L maxW / (L maxR + L maxG + L maxB )} / (1 + t 1 )
= (1 + 1) / (1 + 0.5) = 1.33
And therefore
1 / [{1 + t 1 (1−d maxALL )} d maxALL ]
≦ {1 + L maxW / (L maxR + L maxG + L maxB )} / (1 + t 1 )
Because
t 2 = 1 / [{1 + t1 (1-d maxALL)} d maxALL] = 1.00
become.

そして、dmax=1のときは、
{1+t(1−dmax)}t
=63{1+0.5(1−1)}1.00=63.00
{1+t(1−dmax)}t
=0{1+0.5(1−1)}1.00=0
{1+t(1−dmax)}t
=0{1+0.5(1−1)}1.17=0
2min=0
C=0
であり、
D′=D{1+t(1−dmax)}t−C=63
D′=D{1+t(1−dmax)}t−C=0
D′=D{1+t(1−dmax)}t−C=0
となるため、
D′=63
D′=0
D′=0
D′W=0
となり、輝度が22cd/m2の赤色の原色表示が得られる。この原色表示の輝度は、前
記比較例の駆動方法による原色表示の輝度と同じである。
And when d max = 1,
D R {1 + t 1 (1-d max )} t 2
= 63 {1 + 0.5 (1-1)} 1.00 = 63.00
D G {1 + t 1 (1−d max )} t 2
= 0 {1 + 0.5 (1-1)} 1.00 = 0
D B {1 + t 1 (1−d max )} t 2
= 0 {1 + 0.5 (1-1)} 1.17 = 0
D 2min = 0
C = 0
And
D ′ R = D R {1 + t 1 (1−d max )} t 2 −C = 63
D ′ G = D G {1 + t 1 (1−d max )} t 2 −C = 0
D ′ B = D B {1 + t 1 (1−d max )} t 2 −C = 0
So that
D ′ R = 63
D ′ G = 0
D ′ B = 0
D'W = 0
Thus, a primary color display of red having a luminance of 22 cd / m 2 is obtained. Brightness of the primary color display, primary color display of be the same as the luminance by the driving method of the comparative example.

なお、ここではdmaxALL=1.00としたが、前記dmaxALLが他の値であるときは、前記原色表示の輝度を前記比較例の駆動方法による原色表示の輝度よりも高くなる。 Here, d maxALL = 1.00, but when the d maxALL is another value, the luminance of the primary color display is higher than the luminance of the primary color display by the driving method of the comparative example.

このように、本駆動方法によれば、入力された赤、緑、青の3色の階調データの階調値が互いに異なるときの前記表示要素14の中間色表示の色度が、前記3色画素表示素子と同じであるため、各表示要素14に、前記赤、緑、青の3色の階調データにより定められた中間色を色ずれ無く表示させ、色再現性の良いカラー画像を表示することができる。 Thus, according to this driving method, the chromaticity of the intermediate color display of the display element 14 when the gradation values of the input gradation data of the three colors red, green, and blue are different from each other is the three colors. because the same as the pixel display elements, each display element 14, the red, green, neutral colors defined by the gradation data of three colors of blue to display color misregistration without display good color images with high color reproducibility can do.

また、本駆動方法によれば、前記比較例の駆動方法に比べて、白表示の輝度をさらに高くすることができる。   Further, according to the present driving method, it is possible to further increase the brightness of white display as compared with the driving method of the comparative example.

しかも、本駆動方法によれば、前記白表示と中間色表示との輝度比が、前記比較例の駆動方法による白表示と中間色表示との輝度比と同じであるため、前記比較例の駆動方法に比べて中間色表示の輝度も高くすることができる。 Moreover, the according to the driving method, the brightness ratio of the white display and gray scale display is, since Comparative Example white display and intermediate color same is the luminance ratio of the display by the driving method, the driving method of the comparative example Compared to the above, the brightness of the intermediate color display can be increased.

なお、本駆動方法において、上述したように、前のフレームにおける全ての表示要素14それぞれの最大輝度率差dmaxのうちの最も大きい値を次のフレームのdmaxALLとする場合は、
{1+t(1−dmax)}t−Cの整数化値
{1+t(1−dmax)}t−Cの整数化値
{1+t(1−dmax)}t−Cの整数化値
のいずれか1つまたは2つ以上の値が63を超えることがあり、63を超えた値は、そのまま駆動階調データの階調値D′,D′,D′とすることができない。
In this driving method, as described above, when the largest value among the maximum luminance rate differences d max of all the display elements 14 in the previous frame is set as d maxALL of the next frame,
D R {1 + t 1 (1−d max )} t 2 −C integerized value D G {1 + t 1 (1−d max )} t 2 −C integerized value D B {1 + t 1 (1−d max )} Any one or more of the integer values of t 2 -C may exceed 63, and values exceeding 63 may be used as the gradation values D ′ R , D of the drive gradation data as they are. ′ G , D ′ B cannot be set.

その場合は、赤、緑、青の3色の駆動階調データの階調値D′,D′,D′を、
{1+t(1−dmax)}t−C>63のときはD′=63
{1+t(1−dmax)}t−C>63のときはD′=63
{1+t(1−dmax)}t−C>63のときはD′=63
にすればよく、このようにすることにより、ほとんどのカラー画像を、視観上の問題を生じること無く表示することができる。
In that case, the gradation values D ′ R , D ′ G and D ′ B of the driving gradation data of the three colors of red, green and blue are
When D R {1 + t 1 (1−d max )} t 2 −C> 63, D ′ R = 63
When D G {1 + t 1 (1−d max )} t 2 −C> 63, D ′ G = 63
When D B {1 + t 1 (1−d max )} t 2 −C> 63, D ′ B = 63
By doing so, most color images can be displayed without causing any visual problems.

液晶表示装置の構成図。1 is a configuration diagram of a liquid crystal display device. 液晶表示素子の一部分の断面図。FIG. 3 is a cross-sectional view of a part of a liquid crystal display element. 前記液晶表示素子の画素配列例を示す図。The figure which shows the pixel array example of the said liquid crystal display element. 前記液晶表示素子の他の画素配列例を示す図。The figure which shows the other pixel arrangement example of the said liquid crystal display element. 前記液晶表示素子の他の画素配列例を示す図。The figure which shows the other pixel arrangement example of the said liquid crystal display element. 前記液晶表示素子の他の画素配列例を示す図。The figure which shows the other pixel arrangement example of the said liquid crystal display element. 前記液晶表示素子の赤、緑、青及び白の4色の画素にそれぞれ前記最大階調の階調データに対応したデータ信号を供給したとき各色の画素から出射する赤、緑、青及び白の4色の光の分光特性図。When a data signal corresponding to the gradation data of the maximum gradation is supplied to the four color pixels of red, green, blue and white of the liquid crystal display element, red, green, blue and white emitted from the pixels of each color FIG. 4 is a spectral characteristic diagram of light of four colors.

符号の説明Explanation of symbols

1…液晶表示素子、13R…赤色画素、13G…緑色画素、13B…青色画素、13W…白色画素、14…表示要素、15…駆動手段。   DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display element, 13R ... Red pixel, 13G ... Green pixel, 13B ... Blue pixel, 13W ... White pixel, 14 ... Display element, 15 ... Drive means.

Claims (1)

赤、緑、青及び白の4色の複数の画素が交互にマトリックス状に配列させて形成され、互いに隣合う前記赤、緑、青及び白の各色1つずつの4つの画素を1単位とする複数の表示要素によりカラー画像を表示する液晶表示素子の駆動方法において、
入力された赤、緑、青の3色の階調データに基づいて、
前記赤、緑、青及び白の4色の画素それぞれの最大階調輝度をLmaxR,LmaxG,LmaxB,LmaxW
前記赤、緑、青の3色の画素それぞれの前記入力された赤、緑、青の3色の階調データに対応する輝度を入力データ対応輝度L,L,L
前記赤、緑、青の3色の画素それぞれの前記最大階調輝度LmaxR,LmaxG,LmaxBに対する前記入力データ対応輝度L,L,Lの割合L/LmaxR,L/LmaxG,L/LmaxBをそれぞれ入力データ対応輝度率R,R,R
前記複数の表示要素毎の前記赤、緑、青の3色の画素相互の前記入力データ対応輝度率R,R,Rの差の絶対値|R−R|,|R−R|,|R−R|のうちの最大値を最大輝度率差dmax
1画面のカラー画像を表示するための1フレームにおける全ての表示要素それぞれの前記最大輝度率差dmaxのうちの最も大きい値をdmaxALL
前記入力された赤、緑、青の3色の階調データの階調値をD ,D ,D
前記複数の表示要素毎の赤、緑、青及び白の4色の駆動階調データの階調値をD′ ,D′ ,D′ ,D′
とするとき、
前記液晶表示素子は、前記赤、緑、青及び白の4色の画素それぞれの輝度がこれらの画素を駆動するための前記駆動階調データの階調値に比例する特性を有しており、
D′ はD {1+t (1−d max )}t −Cを整数化した値、
D′ はD {1+t (1−d max )}t −Cを整数化した値、
D′ はD {1+t (1−d max )}t −Cを整数化した値、
D′ はCを整数化した値、
ただし、Cは、D {1+t (1−d max )}t ,D {1+t (1−d max )}t ,D {1+t (1−d max )}t のうちの最も小さい値をD 2min とするとき、当該D 2min が最大階調未満の場合は当該D 2min を整数化した値、当該D 2min が最大階調以上の場合は前記最大階調の値、
また、
は、0≦t ≦L maxW /(L maxR +L maxG +L maxB )の範囲の任意の設定値、
は、1/[{1+t (1−d maxALL )}d maxALL ]≦{1+L maxW /(L maxR +L maxG +L maxB )}/(1+t )のとき、
=1/[{1+t (1−d maxAL L)}d maxALL ]に設定され、
{1+L maxW /(L maxR +L maxG +L maxB )}/(1+t )<1/[{1+t (1−d maxALL )}d maxALL ]のとき、
={1+L maxW /(L maxR +L maxG +L maxB )}/(1+t )に設定される、係数、
にそれぞれ設定される、
ことを特徴とする液晶表示素子の駆動方法。
A plurality of pixels of four colors of red, green, blue, and white are alternately arranged in a matrix, and four pixels of each of the red, green, blue, and white colors adjacent to each other are defined as one unit. In a driving method of a liquid crystal display element that displays a color image by a plurality of display elements,
Based on the input gradation data of red, green and blue,
The maximum gradation luminance of each of the red, green, blue and white pixels is expressed as L maxR , L maxG , L maxB , L maxW ,
Luminances corresponding to the input three-color gradation data of red, green, and blue for each of the red, green, and blue pixels are represented by input data-corresponding luminances L R , L G , L B ,
The red, green, and blue three color pixels each of the maximum gradation luminance L maxR, L maxG, L the input to maxB data corresponding luminance L R, L G, the ratio L R / L maxR of L B, L G / L maxG and L B / L maxB are input data corresponding luminance rates R R , R G , R B , respectively.
The red for each of the plurality of display elements, green, the input data corresponding luminance of the pixels mutual three colors blue R R, R G, the absolute value of the difference between R B | R R -R G | , | R G −R B |, | R B −R R | is the maximum luminance ratio difference d max ,
D maxALL , the largest value among the maximum luminance rate differences d max of all the display elements in one frame for displaying a color image of one screen,
The gradation values of the inputted three-color gradation data of red, green, and blue are represented by D R , D G , D B ,
The gradation values of the drive gradation data of red, green, blue and white for each of the plurality of display elements are represented by D ′ R , D ′ G , D ′ B , D ′ W ,
And when
The liquid crystal display element has a characteristic that the luminance of each of the four colors of red, green, blue and white is proportional to the gradation value of the driving gradation data for driving these pixels,
D ′ R is a value obtained by converting D R {1 + t 1 (1−d max )} t 2 −C into an integer,
D ′ G is a value obtained by converting D G {1 + t 1 (1−d max )} t 2 −C into an integer,
D ′ B is a value obtained by converting D B {1 + t 1 (1−d max )} t 2 −C into an integer,
D ′ W is a value obtained by converting C into an integer,
However, C is, D R {1 + t 1 (1-d max)} t 2, D G {1 + t 1 (1-d max)} t 2, D B {1 + t 1 (1-d max)} of t 2 When the smallest value among them is D 2 min , when D 2 min is less than the maximum gradation , the value obtained by converting D 2 min into an integer, and when D 2 min is greater than or equal to the maximum gradation, the value of the maximum gradation,
Also,
t 1 is an arbitrary set value in a range of 0 ≦ t 1 ≦ L maxW / (L maxR + L maxG + L maxB ),
t 2 is 1 / [{1 + t 1 (1−d maxALL )} d maxALL ] ≦ {1 + L maxW / (L maxR + L maxG + L maxB )} / (1 + t 1 )
t 2 = 1 / [{1 + t 1 (1−d max ALL )} d max ALL ],
{1 + L maxW / (L maxR + L maxG + L maxB )} / (1 + t 1 ) <1 / [{1 + t 1 (1−d maxALL )} d maxALL ]
a coefficient set to t 2 = {1 + L maxW / (L maxR + L maxG + L maxB )} / (1 + t 1 ),
Respectively set to
A driving method of a liquid crystal display element.
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