JP2008164849A - Liquid crystal display device - Google Patents

Liquid crystal display device Download PDF

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JP2008164849A
JP2008164849A JP2006353306A JP2006353306A JP2008164849A JP 2008164849 A JP2008164849 A JP 2008164849A JP 2006353306 A JP2006353306 A JP 2006353306A JP 2006353306 A JP2006353306 A JP 2006353306A JP 2008164849 A JP2008164849 A JP 2008164849A
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liquid crystal
crystal display
reference voltage
display panel
correction data
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Katsuhiko Kishida
克彦 岸田
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LG Display Co Ltd
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LG Display Co Ltd
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Priority to KR1020070138594A priority patent/KR20080061320A/en
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3648—Control of matrices with row and column drivers using an active matrix
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1345—Conductors connecting electrodes to cell terminals
    • G02F1/13454—Drivers integrated on the active matrix substrate
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3696—Generation of voltages supplied to electrode drivers
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0247—Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0257—Reduction of after-image effects

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device that securely avoids flickering and burning by avoiding the occurrence of a residual DC component for a common voltage. <P>SOLUTION: The liquid crystal display device includes: a liquid crystal display panel 30; a display control circuit 10A which generates a reference voltage VR for grayscale display based upon a video signal A; and a driver circuit 20 which applies the common voltage to a common electrode of the liquid crystal display panel 30 and also applies an AC drive signal based upon the reference voltage VR to respective pixel electrodes of the liquid crystal display panel 30. The display control circuit 10A includes a reference voltage generating circuit 12A having a storage device 11A. The storage device 11A stores correction data based upon an actual display image on the liquid crystal display panel 30, and the reference voltage generating circuit 12A outputs the reference voltage based upon the video signal A to the driver circuit 20 after correcting the reference voltage using the correction data. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

この発明は、コモン電極に対して画素電極を正負方向に交流駆動して画像を表示する液晶表示装置に関し、特に階調表示用の基準電圧に対する補正データが格納された液晶表示装置に関するものである。   The present invention relates to a liquid crystal display device that displays an image by alternatingly driving a pixel electrode with respect to a common electrode in positive and negative directions, and more particularly to a liquid crystal display device that stores correction data for a reference voltage for gradation display. .

従来の液晶表示装置は、輝度特性やホワイトバランスの製造ばらつきなどを改善して階調表示性能を向上させるために、表示制御回路内にルックアップテーブル（ＬＵＴ）が設けられており、ＬＵＴ内に基準電圧に対する所定の補正データがあらかじめ格納されている（たとえば、特許文献１、特許文献２参照）。   A conventional liquid crystal display device is provided with a look-up table (LUT) in the display control circuit in order to improve the gradation display performance by improving luminance characteristics and white balance manufacturing variation. Predetermined correction data for the reference voltage is stored in advance (see, for example, Patent Document 1 and Patent Document 2).

図８は特許文献１または特許文献２に記載された従来の液晶表示装置の構成を示すブロック図である。図８において、従来の液晶表示装置１は、Ｄ／Ａ変換器により構成された表示制御回路１０と、ドライバ回路２０と、液晶表示パネル３０とを備えている。   FIG. 8 is a block diagram showing a configuration of a conventional liquid crystal display device described in Patent Document 1 or Patent Document 2. In FIG. In FIG. 8, the conventional liquid crystal display device 1 includes a display control circuit 10 configured by a D / A converter, a driver circuit 20, and a liquid crystal display panel 30.

表示制御回路１０は、ルックアップテーブル（ＬＵＴ）からなる記憶装置１１と、基準電圧生成回路１２とを備え、外部から入力される映像信号Ａ（デジタル信号）に基づいて、Ｄ／Ａ変換された表示信号Ｂと階調表示用の基準電圧ＶＲ（アナログ信号）とを生成する。   The display control circuit 10 includes a storage device 11 including a look-up table (LUT) and a reference voltage generation circuit 12, and is D / A converted based on a video signal A (digital signal) input from the outside. A display signal B and a reference voltage VR (analog signal) for gradation display are generated.

記憶装置１１内のルックアップテーブルは、映像信号Ａを補正するための補正データをあらかじめ保存しており、入力された映像信号Ａを、補正データで補正し、製造ばらつきなどを修正した映像信号に変換する。基準電圧生成回路１２は、補正後の映像信号に基づいて、階調表示用の基準電圧ＶＲを生成する。   The look-up table in the storage device 11 stores correction data for correcting the video signal A in advance, and the input video signal A is corrected with the correction data to obtain a video signal in which manufacturing variations are corrected. Convert. The reference voltage generation circuit 12 generates a reference voltage VR for gradation display based on the corrected video signal.

ドライバ回路２０は、液晶表示パネル３０のコモン電極（図示せず）にコモン電圧Ｖｃｏｍを印加するとともに、表示信号Ｂおよび基準電圧ＶＲに基づく交流駆動信号を液晶表示パネル３０の各画素電極に印加して、液晶表示パネル３０に所望の画像を表示させる。   The driver circuit 20 applies a common voltage Vcom to a common electrode (not shown) of the liquid crystal display panel 30 and applies an AC drive signal based on the display signal B and the reference voltage VR to each pixel electrode of the liquid crystal display panel 30. Thus, a desired image is displayed on the liquid crystal display panel 30.

図９は従来の液晶表示装置１における中心電圧と駆動電圧との関係を図式的に示すタイミングチャートである。図９において、中心電圧の上下に示した交流駆動用の正極電位（Ｖ＋）および負極電位（Ｖ−）は、液晶表示パネル３０の画素電極（図示せず）に印加される。   FIG. 9 is a timing chart schematically showing the relationship between the center voltage and the drive voltage in the conventional liquid crystal display device 1. In FIG. 9, a positive electrode potential (V +) and a negative electrode potential (V−) for AC driving shown above and below the center voltage are applied to pixel electrodes (not shown) of the liquid crystal display panel 30.

正極電位（Ｖ＋）および負極電位（Ｖ−）は、それぞれ、白色表示用の最大電位Ｖ＋ｍａｘ、Ｖ−ｍａｘと、黒色表示用の最小電位Ｖ＋ｍｉｎ、Ｖ−ｍｉｎとの間の任意数の階調電位を有する。画素電極は、たとえば白色表示時には、実線矢印で示すように最大電位Ｖ＋ｍａｘ、Ｖ−ｍａｘの振幅で交流駆動され、また、白色表示時には、２点鎖線矢印で示すように、最小電位Ｖ＋ｍｉｎ、Ｖ−ｍｉｎの振幅で交流駆動される。   The positive electrode potential (V +) and the negative electrode potential (V−) are respectively any number of gradation potentials between the maximum potentials V + max and V−max for white display and the minimum potentials V + min and V−min for black display. Have For example, when displaying white, the pixel electrode is AC driven with amplitudes of maximum potentials V + max and V-max as indicated by solid arrows, and when displaying white, minimum potentials V + min and V− are indicated as indicated by two-dot chain arrows. AC driving is performed with an amplitude of min.

図８および図９に示すように、液晶表示装置１において、液晶表示パネル３０の画素電極には、映像信号Ａに基づく交流駆動するための正極電位（Ｖ＋）および負極電位（Ｖ−）が、表示制御回路１０およびドライバ回路２０を介して印加される。このとき、表示制御回路１０内の記憶装置１１において、映像信号Ａには、所定の補正データによる補正が施されている。   As shown in FIGS. 8 and 9, in the liquid crystal display device 1, a positive electrode potential (V +) and a negative electrode potential (V−) for AC driving based on the video signal A are applied to the pixel electrodes of the liquid crystal display panel 30. The voltage is applied via the display control circuit 10 and the driver circuit 20. At this time, in the storage device 11 in the display control circuit 10, the video signal A is corrected by predetermined correction data.

しかし、所定の補正データのみによる補正では、個々の液晶表示装置１のばらつきを完全に吸収することができず、正極電位（Ｖ＋）と負極電位（Ｖ−）との間にアンバランスが生じ、液晶表示パネル３０での表示画面にフリッカが発生する可能性がある。また、正極電位（Ｖ＋）と負極電位（Ｖ−）とのバランスが悪い状態で交流電圧を印加し続けると、コモン電極と画素電極との間の液晶にＤＣ成分が残り、残留ＤＣ成分により焼きつきが発生する。   However, in the correction based only on the predetermined correction data, the dispersion of the individual liquid crystal display devices 1 cannot be completely absorbed, and an imbalance occurs between the positive electrode potential (V +) and the negative electrode potential (V−). Flicker may occur on the display screen of the liquid crystal display panel 30. In addition, if an AC voltage is continuously applied in a state where the positive electrode potential (V +) and the negative electrode potential (V−) are in a poor balance, a DC component remains in the liquid crystal between the common electrode and the pixel electrode, and the residual DC component causes a burning. A splinter occurs.

特に、図９から明らかなように、正極電位（Ｖ＋）および負極電位（Ｖ−）は、グランド電位ＧＮＤに対するＤＣ成分が互いに異なることから、液晶表示装置１内の回路インピーダンスによる正極電位（Ｖ＋）および負極電位（Ｖ−）に対する電圧降下成分が非対称となるので、単に補正データによる補正を施しても、交流駆動時の残留ＤＣ成分をなくすことはできない。たとえば、白色表示時における正極の最大電位Ｖ＋ｍａｘでのインピーダンス成分による電圧降下は、負極の最大電位Ｖ＋ｍｉｎでのインピーダンス成分による電圧降下よりも著しく大きくなる。   In particular, as apparent from FIG. 9, the positive electrode potential (V +) and the negative electrode potential (V−) have different DC components with respect to the ground potential GND, so that the positive electrode potential (V +) due to the circuit impedance in the liquid crystal display device 1. Since the voltage drop component with respect to the negative electrode potential (V−) is asymmetrical, it is not possible to eliminate the residual DC component at the time of AC driving even if correction is simply performed using correction data. For example, the voltage drop due to the impedance component at the maximum potential V + max of the positive electrode during white display is significantly larger than the voltage drop due to the impedance component at the maximum potential V + min of the negative electrode.

特開２００４−０９４０１７号公報JP 2004-094017 A 特開２００４−０６２１８７号公報JP 2004-062187 A

従来の液晶表示装置では、製造ばらつきなどを修正するために、記憶装置１１内のＬＵＴ内にあらかじめ所定の補正データを格納しているが、映像信号Ａを補正データで変換することのみでは、液晶表示装置１の個々のばらつきや、正極電位（Ｖ＋）および負極電位（Ｖ−）の非対称特性を完全に吸収することができないので、フリッカや焼きつきなどの発生を確実に回避することができないという課題があった。   In the conventional liquid crystal display device, predetermined correction data is stored in advance in the LUT in the storage device 11 in order to correct manufacturing variations and the like. However, only by converting the video signal A with the correction data, the liquid crystal display Since individual variations of the display device 1 and the asymmetrical characteristics of the positive electrode potential (V +) and the negative electrode potential (V−) cannot be completely absorbed, the occurrence of flickering or burn-in cannot be reliably avoided. There was a problem.

この発明は、個々の液晶表示装置の実際の表示画面に応じた補正データをあらかじめ格納することにより、コモン電圧に対する残留ＤＣ成分の発生を回避して、フリッカや焼きつきなどの発生を確実に回避した液晶表示装置を得ることを目的とする。   The present invention stores correction data corresponding to the actual display screen of each liquid crystal display device in advance, thereby avoiding the occurrence of a residual DC component with respect to the common voltage and reliably preventing the occurrence of flicker, burn-in, etc. An object is to obtain a liquid crystal display device.

この発明による液晶表示装置は、外部から入力される映像信号に基づく画像を表示する液晶表示パネルと、映像信号に基づきＤ／Ａ変換された階調表示用の基準電圧を生成する表示制御回路と、液晶表示パネルのコモン電極にコモン電圧を印加するとともに、基準電圧に基づく交流駆動信号を液晶表示パネルの各画素電極に印加して液晶表示パネルに画像を表示させるドライバ回路と、を備えた液晶表示装置において、表示制御回路は、記憶装置を有する基準電圧生成回路を含み、記憶装置は、液晶表示パネルにおける実際の表示画像に基づく補正データを格納し、基準電圧生成回路は、映像信号に基づく基準電圧を、補正データを用いて補正した後にドライバ回路に出力するものである。   A liquid crystal display device according to the present invention includes a liquid crystal display panel that displays an image based on a video signal input from the outside, a display control circuit that generates a reference voltage for gradation display that is D / A converted based on the video signal, and And a driver circuit that applies a common voltage to the common electrode of the liquid crystal display panel and applies an AC drive signal based on the reference voltage to each pixel electrode of the liquid crystal display panel to display an image on the liquid crystal display panel. In the display device, the display control circuit includes a reference voltage generation circuit having a storage device, the storage device stores correction data based on an actual display image in the liquid crystal display panel, and the reference voltage generation circuit is based on the video signal. The reference voltage is corrected using the correction data and then output to the driver circuit.

この発明によれば、個々の液晶表示装置の実際の表示画面に応じた補正データをあらかじめ格納することにより、コモン電圧に対する残留ＤＣ成分の発生を回避して、フリッカや焼きつきなどの発生を確実に回避することができる。   According to the present invention, correction data corresponding to the actual display screen of each liquid crystal display device is stored in advance, thereby avoiding generation of a residual DC component with respect to the common voltage and ensuring occurrence of flicker, burn-in, and the like. Can be avoided.

実施の形態１．
図１はこの発明の実施の形態１に係る液晶表示装置を示すブロック図である。図１において、前述（図８参照）と同様のものについては、前述と同一符号を付して、または符号の後に「Ａ」を付して詳述を省略する。 Embodiment 1 FIG.
1 is a block diagram showing a liquid crystal display device according to Embodiment 1 of the present invention. In FIG. 1, the same parts as those described above (see FIG. 8) are denoted by the same reference numerals as those described above, or “A” after the reference numerals, and detailed description thereof is omitted.

この発明の実施の形態１に係る液晶表示装置１Ａは、外部から入力される映像信号Ａに基づく画像を表示する液晶表示パネル３０と、映像信号Ａに基づきＤ／Ａ変換された表示信号Ｂおよび階調表示用の基準電圧ＶＲを生成する表示制御回路１０Ａと、液晶表示パネル３０のコモン電極にコモン電圧Ｖｃｏｍを印加するとともに、基準電圧ＶＲに基づく交流駆動信号を液晶表示パネル３０の各画素電極に印加して液晶表示パネル３０に画像を表示させるドライバ回路２０と、を備えている。   A liquid crystal display device 1A according to Embodiment 1 of the present invention includes a liquid crystal display panel 30 that displays an image based on a video signal A input from the outside, a display signal B that is D / A converted based on the video signal A, and A display control circuit 10A that generates a reference voltage VR for gradation display, a common voltage Vcom is applied to the common electrode of the liquid crystal display panel 30, and an AC drive signal based on the reference voltage VR is applied to each pixel electrode of the liquid crystal display panel 30. And a driver circuit 20 that causes the liquid crystal display panel 30 to display an image.

表示制御回路１０Ａは、記憶装置１１Ａを有する基準電圧生成回路１２Ａを含む。記憶装置１１Ａは、液晶表示パネル３０における実際の表示画像に基づく補正データを格納しており、基準電圧生成回路１２Ａは、映像信号Ａに基づく基準電圧ＶＲを、記憶装置１１Ａ内の補正データを用いて補正した後にドライバ回路２０に出力する。記憶装置１１Ａ内の補正データは、交流駆動信号の正極電位（Ｖ＋）および負極電位（Ｖ−）の両方に対する補正データを含む。   The display control circuit 10A includes a reference voltage generation circuit 12A having a storage device 11A. The storage device 11A stores correction data based on the actual display image on the liquid crystal display panel 30, and the reference voltage generation circuit 12A uses the reference voltage VR based on the video signal A using the correction data in the storage device 11A. Are corrected and output to the driver circuit 20. The correction data in the storage device 11A includes correction data for both the positive electrode potential (V +) and the negative electrode potential (V−) of the AC drive signal.

また、記憶装置１１Ａ内の補正データは、交流駆動信号のフィードバック調整時（イニシャライズ時）に液晶表示パネル３０および記憶装置１１Ａに接続される制御用パソコン（後述する）からの制御信号により記憶装置１１Ａに格納される。すなわち、記憶装置１１Ａは、液晶表示装置１Ａの出荷前の階調補正（輝度補正）における補正データを保存している。   Further, the correction data in the storage device 11A is stored in the storage device 11A by a control signal from a liquid crystal display panel 30 and a control personal computer (described later) connected to the storage device 11A at the time of feedback adjustment (initialization) of the AC drive signal. Stored in That is, the storage device 11A stores correction data for gradation correction (luminance correction) before shipment of the liquid crystal display device 1A.

次に、図２〜図７を参照しながら、図１に示したこの発明の実施の形態１に係る液晶表示装置１Ａ内の補正データの格納処理について説明する。
図２はこの発明の実施の形態１における調整装置を概略的に示すブロック図であり、交流駆動信号の調整時に用いられる制御基板１３と、ドライバ回路２０に含まれるソースドライバ２１とを示している。なお、表示制御回路１０Ａは、あらかじめ制御基板１３上に実装されてもよい。 Next, correction data storage processing in the liquid crystal display device 1A according to Embodiment 1 of the present invention shown in FIG. 1 will be described with reference to FIGS.
FIG. 2 is a block diagram schematically showing the adjustment device according to the first embodiment of the present invention, and shows a control board 13 used at the time of adjusting an AC drive signal and a source driver 21 included in the driver circuit 20. . The display control circuit 10A may be mounted on the control board 13 in advance.

制御基板１３は、制御用パソコン（図示せず）の制御下で、コモン電圧Ｖｃｏｍと、階調表示用の正極電位（Ｖ＋）および負極電位（Ｖ−）に対応した基準電圧ＶＲとを出力し、ソースドライバ２１を介して液晶表示パネル３０を駆動する。   The control board 13 outputs a common voltage Vcom and a reference voltage VR corresponding to a positive potential (V +) and a negative potential (V−) for gradation display under the control of a control personal computer (not shown). The liquid crystal display panel 30 is driven via the source driver 21.

図３はコモン電圧Ｖｃｏｍと駆動電圧（交流駆動信号）との関係を図式的に示すタイミングチャートであり、コモン電圧Ｖｃｏｍに対する正極電位（Ｖ＋）および負極電位（Ｖ−）の時間変化を示している。また、正極電位（Ｖ＋）および負極電位（Ｖ−）において、最大電位Ｖ＋ｍａｘ、Ｖ−ｍａｘと、最小電位Ｖ＋ｍｉｎ、Ｖ−ｍｉｎとの間に、一例として、イニシャライズ調整時（後述する）に関連した各６段階の基準電圧ＶＲ（破線参照）を示している。   FIG. 3 is a timing chart schematically showing the relationship between the common voltage Vcom and the drive voltage (AC drive signal), and shows the time variation of the positive electrode potential (V +) and the negative electrode potential (V−) with respect to the common voltage Vcom. . Further, in the positive electrode potential (V +) and the negative electrode potential (V−), the maximum potentials V + max and V−max and the minimum potentials V + min and V−min are related to the initialization adjustment (described later) as an example. Each of the six stages of reference voltages VR (see broken lines) is shown.

図４は基準電圧生成回路１２Ｂの他の構成例を示す回路図である。図４において、基準電圧生成回路１２Ｂは、Ｄ／Ａ変換器からなる基準電圧生成回路１２Ａに代えて、複数の可変抵抗手段Ｒ１〜Ｒ５からなるデジタルポテンショメータにより構成されている。可変抵抗手段Ｒ１〜Ｒ５の各一端からは、正極および負極ごとに複数段の基準電圧Ｖ２５５、Ｖ１２７、Ｖ０が生成される。   FIG. 4 is a circuit diagram showing another configuration example of the reference voltage generation circuit 12B. In FIG. 4, the reference voltage generation circuit 12B is configured by a digital potentiometer including a plurality of variable resistance means R1 to R5, instead of the reference voltage generation circuit 12A including a D / A converter. A plurality of stages of reference voltages V255, V127, and V0 are generated for each of the positive and negative electrodes from each end of the variable resistance means R1 to R5.

図５は図２の調整装置によるコモン電圧Ｖｃｏｍの調整方法を示す説明図であり、デジタル信号の映像信号Ａが８ビットの場合を例にとり、最大電位Ｖ＋ｍａｘ（＋２５５）、Ｖ−ｍａｘ（−２５５）と、最小電位Ｖ＋ｍｉｎ（＋０）、Ｖ−ｍｉｎ（−０）と、フリッカ調整用に上下シフトされるコモン電圧Ｖｃｏｍ（１点鎖線参照）とを示している。   FIG. 5 is an explanatory diagram showing a method of adjusting the common voltage Vcom by the adjusting device of FIG. 2, taking the case where the digital video signal A is 8 bits as an example, and the maximum potentials V + max (+255) and V-max (−255). ), Minimum potentials V + min (+0), V-min (-0), and a common voltage Vcom (see the one-dot chain line) shifted up and down for flicker adjustment.

図６は図２の調整装置による階調（基準電圧ＶＲ）の調整方法を示す説明図であり、輝度調整時に振幅が増減シフトされるとともに、フリッカ調整時に上下シフトされる正極電位（Ｖ＋）および負極電位（Ｖ−）を示している。   FIG. 6 is an explanatory diagram showing a method of adjusting the gradation (reference voltage VR) by the adjusting device of FIG. 2, and the positive potential (V +) and the amplitude that are shifted up and down during luminance adjustment and shifted up and down during flicker adjustment and The negative electrode potential (V−) is shown.

図７は図２の調整装置によるコモン電圧Ｖｃｏｍおよび基準電圧ＶＲの調整方法を示すフローチャートであり、調整時（初期設定時）における補正データの格納処理手順を示している。液晶表示装置１Ａの調整処理は、図７のように実行される。   FIG. 7 is a flowchart showing a method of adjusting the common voltage Vcom and the reference voltage VR by the adjusting device of FIG. 2, and shows a correction data storing process procedure during adjustment (initial setting). The adjustment process of the liquid crystal display device 1A is executed as shown in FIG.

図７において、まず、制御用パソコンは、初期設定処理により、フリッカ測定部および輝度測定部（図示せず）の初期化を行う（ステップＳ１）。   In FIG. 7, first, the control personal computer initializes a flicker measuring unit and a luminance measuring unit (not shown) by an initial setting process (step S1).

続いて、制御信号をソースドライバ２１に出力して液晶表示パネル３０を駆動し、液晶表示パネル３０の撮像信号を、フリッカ測定部を介してフィードバックしながら、液晶表示パネル３０のコモン電極に印加するコモン電圧Ｖｃｏｍの調整処理を行う（ステップＳ２）。このとき、たとえば８ビットの「２５５」、「０」階調表示で、液晶表示パネル３０の表示画面のフリッカが最初となるように、図５のようにコモン電圧Ｖｃｏｍをシフト調整する。   Subsequently, the control signal is output to the source driver 21 to drive the liquid crystal display panel 30, and the imaging signal of the liquid crystal display panel 30 is applied to the common electrode of the liquid crystal display panel 30 while being fed back via the flicker measurement unit. Adjustment processing of the common voltage Vcom is performed (step S2). At this time, the common voltage Vcom is shift-adjusted as shown in FIG. 5 so that the flicker of the display screen of the liquid crystal display panel 30 is first, for example, in 8-bit “255” and “0” gradation display.

次に、制御信号をソースドライバ２１に出力して液晶表示パネル３０を駆動し、液晶表示パネル３０の撮像信号をフリッカ測定部および輝度測定部を介してフィードバックしながら、階調の調整処理を行う（ステップＳ３）。   Next, the control signal is output to the source driver 21 to drive the liquid crystal display panel 30, and gradation adjustment processing is performed while the imaging signal of the liquid crystal display panel 30 is fed back via the flicker measurement unit and the luminance measurement unit. (Step S3).

このとき、正極電位（Ｖ＋）および負極電位（Ｖ−）に対応した複数段階の基準電圧ＶＲ（たとえば、「２２３」階調、「１９１」階調、「１２７」階調、「６３」階調、「３１」階調、「１」階調）に対して、図６のシフト調整により輝度調整およびフリッカを調整する。   At this time, reference voltages VR (for example, “223” gradation, “191” gradation, “127” gradation, “63” gradation) corresponding to the positive electrode potential (V +) and the negative electrode potential (V−). , “31” gradation, “1” gradation), brightness adjustment and flicker are adjusted by shift adjustment of FIG.

すなわち、ステップＳ３においては、液晶表示パネル３０の表示輝度が駆動制御輝度と一致するように、かつ、フリッカが最小となるようにフィードバック調整する。   That is, in step S3, feedback adjustment is performed so that the display brightness of the liquid crystal display panel 30 matches the drive control brightness and the flicker is minimized.

以上のステップＳ２、Ｓ３により、正極電位（Ｖ＋）および負極電位（Ｖ−）に対応した各８段階の基準電圧ＶＲに対する調整が行われ、所望の輝度で、かつフリッカが発生することのない画像を液晶表示パネル３０に表示させるための各基準電圧ＶＲに対する補正データが、液晶表示装置１Ａに固有のデータ値として得られる。   Through the above steps S2 and S3, adjustments are made to the eight-step reference voltage VR corresponding to the positive electrode potential (V +) and the negative electrode potential (V−), and an image with desired luminance and no flicker is generated. Is obtained as a data value specific to the liquid crystal display device 1A.

最後に、制御用パソコンは、最終的に得られた液晶表示装置１Ａに固有の補正データを、表示制御回路１０Ａ（Ｄ／Ａ変換器）内の記憶装置１１Ａに格納し（ステップＳ４）、図７のイニシャライズ調整処理を終了する。
以下、液晶表示装置１Ａに固有の補正データが格納された表示制御回路１０Ａは、常に所望の輝度でフリッカのない画像を表示することができる。 Finally, the control personal computer stores correction data unique to the liquid crystal display device 1A finally obtained in the storage device 11A in the display control circuit 10A (D / A converter) (step S4). 7 finishes the initialization adjustment process.
Hereinafter, the display control circuit 10A in which correction data unique to the liquid crystal display device 1A is stored can always display an image having desired luminance and no flicker.

以上のように、この発明の実施の形態１によれば、調整処理時（イニシャライズ時）にコモン電圧Ｖｃｏｍを自動調整するとともに、基準電圧ＶＲの正負バランスを調整することができるので、液晶表示装置１Ａの製造工数を削減することができる。
また、液晶表示パネル３０の表示画像の輝度を自動調整することができるので、輝度のばらつきを最小限に抑制することができる。 As described above, according to the first embodiment of the present invention, the common voltage Vcom can be automatically adjusted during the adjustment process (initialization), and the positive / negative balance of the reference voltage VR can be adjusted. The manufacturing man-hour of 1A can be reduced.
In addition, since the brightness of the display image on the liquid crystal display panel 30 can be automatically adjusted, variations in brightness can be minimized.

また、上記自動調整により、正極電圧（Ｖ＋）および負極電圧（Ｖ−）の補正が可能となり、フリッカが減少して残留ＤＣ成分が発生することがないので、液晶表示パネル３０のフリッカ発生や焼きつきなどの不具合を回避することができる。   Further, the automatic adjustment makes it possible to correct the positive voltage (V +) and the negative voltage (V−), and the flicker is reduced and no residual DC component is generated. It is possible to avoid problems such as sticking.

また、表示制御回路１０Ａ（Ｄ／Ａ変換器）を制御基板１３上に実装してもよく、この場合、制御基板１３に実装された表示制御回路１０Ａを用いて、コモン電圧Ｖｃｏｍおよび交流駆動信号（データ電圧）を容易に調整することができる。   Further, the display control circuit 10A (D / A converter) may be mounted on the control board 13, and in this case, the common voltage Vcom and the AC drive signal are displayed using the display control circuit 10A mounted on the control board 13. (Data voltage) can be easily adjusted.

また、輝度調整時（ステップＳ３）において、正極電位（Ｖ＋）および負極電位（Ｖ−）に対する各基準電圧ＶＲの幅として、それぞれ一例について述べたが、正極性および負極性の幅を任意に調整することができる。また、フリッカ調整時において、正極性および負極性の中心電圧を調整してもよい。
また、記憶装置１１Ａとしては、公知のルックアップテーブル（ＬＵＴ）やＲＯＭなどの任意のメモリ手段が適用され得る。 In addition, in the brightness adjustment (step S3), an example has been described as the width of each reference voltage VR with respect to the positive electrode potential (V +) and the negative electrode potential (V−). However, the positive and negative electrode widths are arbitrarily adjusted. can do. Further, at the time of flicker adjustment, the positive and negative center voltages may be adjusted.
As the storage device 11A, any memory means such as a known lookup table (LUT) or ROM can be applied.

なお、上記実施の形態１では、映像信号Ａの補正部分の説明を省略したが、従来装置（図８参照）と同様に、表示制御回路１０Ａ内に映像信号Ａの補正手段（記憶装置１１）を設け、基準電圧ＶＲのみならず映像信号Ａを補正するように構成してもよい。   In the first embodiment, the description of the correction portion of the video signal A is omitted, but the correction means (storage device 11) for the video signal A is provided in the display control circuit 10A as in the conventional device (see FIG. 8). And the video signal A as well as the reference voltage VR may be corrected.

この発明の実施の形態１に係る液晶表示装置の構成を示すブロック図である。It is a block diagram which shows the structure of the liquid crystal display device which concerns on Embodiment 1 of this invention. この発明の実施の形態１におけるコモン電圧および階調表示用の基準電圧の調整装置を概略的に示すブロック図である。It is a block diagram which shows roughly the adjustment apparatus of the reference voltage for the common voltage and gradation display in Embodiment 1 of this invention. この発明の実施の形態１におけるコモン電圧と駆動電圧との関係を図式的に示すタイミングチャートである。3 is a timing chart schematically showing a relationship between a common voltage and a drive voltage in Embodiment 1 of the present invention. この発明の実施の形態１における基準電圧生成回路の他の構成例を示す回路図である。It is a circuit diagram which shows the other structural example of the reference voltage generation circuit in Embodiment 1 of this invention. 図２の調整装置によるコモン電圧の調整方法を示す説明図である。It is explanatory drawing which shows the adjustment method of the common voltage by the adjustment apparatus of FIG. 図２の調整装置による基準電圧の調整方法を示す説明図である。It is explanatory drawing which shows the adjustment method of the reference voltage by the adjustment apparatus of FIG. 図２の調整装置によるコモン電圧および基準電圧の調整手順を示すフローチャートである。It is a flowchart which shows the adjustment procedure of the common voltage and reference voltage by the adjustment apparatus of FIG. 従来の液晶表示装置の構成を示すブロック図である。It is a block diagram which shows the structure of the conventional liquid crystal display device. 従来の液晶表示装置における中心電圧と駆動電圧との関係を図式的に示すタイミングチャートである。It is a timing chart which shows typically the relation between the center voltage and drive voltage in the conventional liquid crystal display device.

符号の説明Explanation of symbols

１Ａ 液晶表示装置、１０Ａ 表示制御回路、１１Ａ 記憶装置、１２Ａ 基準電圧生成回路、２０ ドライバ回路、３０ 液晶表示パネル、Ａ 映像信号、Ｖｃｏｍ コモン電圧、ＶＲ 基準電圧。   1A liquid crystal display device, 10A display control circuit, 11A storage device, 12A reference voltage generation circuit, 20 driver circuit, 30 liquid crystal display panel, A video signal, Vcom common voltage, VR reference voltage.

Claims (4)

外部から入力される映像信号に基づく画像を表示する液晶表示パネルと、
前記映像信号に基づきＤ／Ａ変換された階調表示用の基準電圧を生成する表示制御回路と、
前記液晶表示パネルのコモン電極にコモン電圧を印加するとともに、前記基準電圧に基づく交流駆動信号を前記液晶表示パネルの各画素電極に印加して前記液晶表示パネルに前記画像を表示させるドライバ回路と、
を備えた液晶表示装置において、
前記表示制御回路は、記憶装置を有する基準電圧生成回路を含み、
前記記憶装置は、前記液晶表示パネルにおける実際の表示画像に基づく補正データを格納し、
前記基準電圧生成回路は、前記映像信号に基づく前記基準電圧を、前記補正データを用いて補正した後に前記ドライバ回路に出力することを特徴とする液晶表示装置。 A liquid crystal display panel for displaying an image based on an externally input video signal;
A display control circuit that generates a reference voltage for gradation display that is D / A converted based on the video signal;
A driver circuit that applies a common voltage to the common electrode of the liquid crystal display panel, and applies an AC drive signal based on the reference voltage to each pixel electrode of the liquid crystal display panel to display the image on the liquid crystal display panel;
In a liquid crystal display device comprising:
The display control circuit includes a reference voltage generation circuit having a storage device,
The storage device stores correction data based on an actual display image on the liquid crystal display panel,
The liquid crystal display device, wherein the reference voltage generation circuit outputs the reference voltage based on the video signal to the driver circuit after correcting the reference voltage using the correction data. 前記補正データは、前記交流駆動信号の正極電位および負極電位の両方に対する補正データを含むことを特徴とする請求項１に記載の液晶表示装置。   The liquid crystal display device according to claim 1, wherein the correction data includes correction data for both a positive electrode potential and a negative electrode potential of the AC drive signal. 前記補正データは、前記交流駆動信号のフィードバック調整時に前記液晶表示パネルおよび前記記憶装置に接続される制御用パソコンからの制御信号により前記記憶装置に格納されることを特徴とする請求項１または請求項２に記載の液晶表示装置。   The correction data is stored in the storage device according to a control signal from a control personal computer connected to the liquid crystal display panel and the storage device during feedback adjustment of the AC drive signal. Item 3. A liquid crystal display device according to Item 2. 前記基準電圧生成回路は、デジタルポテンショメータにより構成されたことを特徴とする請求項１から請求項３までのいずれか１項に記載の液晶表示装置。   4. The liquid crystal display device according to claim 1, wherein the reference voltage generation circuit is configured by a digital potentiometer. 5.
JP2006353306A 2006-12-27 2006-12-27 Liquid crystal display device Pending JP2008164849A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102592536A (en) * 2011-12-13 2012-07-18 友达光电股份有限公司 Common voltage supply circuit and method for display and liquid crystal display thereof
CN102938246A (en) * 2012-12-06 2013-02-20 深圳市华星光电技术有限公司 Driving system of liquid crystal display
WO2015000270A1 (en) * 2013-07-05 2015-01-08 合肥京东方光电科技有限公司 Gamma voltage regulation method and system, and electronic device
CN111899698A (en) * 2020-06-18 2020-11-06 南京观海微电子有限公司 Display panel based on double reference voltages

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102592536A (en) * 2011-12-13 2012-07-18 友达光电股份有限公司 Common voltage supply circuit and method for display and liquid crystal display thereof
CN102938246A (en) * 2012-12-06 2013-02-20 深圳市华星光电技术有限公司 Driving system of liquid crystal display
WO2015000270A1 (en) * 2013-07-05 2015-01-08 合肥京东方光电科技有限公司 Gamma voltage regulation method and system, and electronic device
US9653036B2 (en) 2013-07-05 2017-05-16 Boe Technology Group Co., Ltd. Method and system for adjusting gamma voltage, and electronic device
CN111899698A (en) * 2020-06-18 2020-11-06 南京观海微电子有限公司 Display panel based on double reference voltages

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