JP2003058114A - Liquid crystal display element and its driving method - Google Patents
Liquid crystal display element and its driving methodInfo
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- JP2003058114A JP2003058114A JP2001240784A JP2001240784A JP2003058114A JP 2003058114 A JP2003058114 A JP 2003058114A JP 2001240784 A JP2001240784 A JP 2001240784A JP 2001240784 A JP2001240784 A JP 2001240784A JP 2003058114 A JP2003058114 A JP 2003058114A
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、表示素子及びこれ
を用いた表示装置とその駆動方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, a display device using the same, and a driving method thereof.
【０００２】[0002]
【従来の技術】電子ディスプレイには、様々な、種類が
あるが、所定の周期で画像の書き代えることにより、動
画を映す、という原理は、普遍的なものである。画像の
書き換え周波数は通常６０Ｈｚ以上に設定されている。
これは、６０Ｈｚ未満では、人の目がフリッカーを感じ
易くなるためである。ＶＤＴ作業などの長時間使用する
ディスプレイでは、目の疲れを減らすために６０Ｈｚよ
り早い、例えば１２０Ｈｚ程度の書き換え周波数に設定
されている。2. Description of the Related Art There are various types of electronic displays, but the principle of displaying a moving image by rewriting an image at a predetermined cycle is universal. The image rewriting frequency is usually set to 60 Hz or higher.
This is because human eyes are more likely to perceive flicker at frequencies below 60 Hz. In a display used for a long time such as VDT work, the rewriting frequency is set to be faster than 60 Hz, for example, about 120 Hz in order to reduce eye fatigue.
【０００３】液晶表示素子では、液晶を交流駆動し、電
圧極性に依存しない性質を利用して、印加電圧波形は３
０Ｈｚ以上となっているが、画像情報の書き込みは毎秒
６０回以上行われており、実質的に６０Ｈｚ以上の周波
数で書き込んでいる。液晶素子は、消費電力が小さいの
で携帯電話などの携帯機器の表示素子として、広く用い
られている。液晶表示素子は、受光型素子であるため、
外光の光を反射して表示を行う反射型表示の場合、液晶
パネル内で消費する電力は極めて小さい。例えば、携帯
電話などの対角２インチ程度の画面では液晶パネル内の
で消費電力は１ｍＷに満たない。しかし、実際の表示装
置では、液晶を駆動する駆動回路で消費する電力の方が
数十倍大きい。特に、表示画面の内容を保持した画像メ
モリーから１画面分のデータを６０Ｈｚ以上の周波数で
ドライバーＬＳＩへ書き込む時に周波数×画面データ量
の非常に高い周波数でＬＳＩが動作するために消費電力
が大きくなる。書き換え周波数を低くすれば電力は下が
るが、書き換え周波数を６０Ｈｚ未満にすると目がフリ
ッカー（ちらつき）を感じてしまうので、６０Ｈｚ未満
にはできない。In the liquid crystal display device, the liquid crystal is driven by an alternating current, and the applied voltage waveform is 3 by utilizing the property that does not depend on the voltage polarity.
Although it is 0 Hz or more, the writing of image information is performed 60 times or more per second, and writing is substantially performed at a frequency of 60 Hz or more. Liquid crystal devices have low power consumption and are therefore widely used as display devices for mobile devices such as mobile phones. Since the liquid crystal display element is a light receiving element,
In the case of a reflection type display that reflects external light to perform display, the power consumed in the liquid crystal panel is extremely small. For example, in a screen of a diagonal of about 2 inches such as a mobile phone, the power consumption is less than 1 mW in the liquid crystal panel. However, in an actual display device, the power consumed by the drive circuit that drives the liquid crystal is several ten times larger. In particular, when data for one screen is written from the image memory holding the contents of the display screen to the driver LSI at a frequency of 60 Hz or more, the LSI operates at a very high frequency multiplied by the screen data amount, resulting in high power consumption. . If the rewriting frequency is lowered, the power is reduced, but if the rewriting frequency is less than 60 Hz, the eyes feel flicker (flickering), so it cannot be less than 60 Hz.
【０００４】携帯電話やＯＡ機器では、表示画面は、ほ
とんどの時間、静止画が表示されており、表示画面を更
新する必要はないが、フリッカーを避けるために静止画
表示でも駆動し続けないならない。そこで、静止画表示
の時の、前述のような画像メモリーの転送による消費電
力を抑えるために、ドライバーＬＳＩの内部に画像メモ
リーを内蔵した、ＲＡＭ内蔵ドライバーが市販されてお
り、図３のような表示素子を構成している。ＲＡＭ内蔵
ドライバー３０は、液晶を駆動するソースドライバー３
１とＲＡＭ３２をＬＳＩ内部に有しており、画面内容を
書き換えない時は、ＲＡＭ内蔵ドライバー３０内部でデ
ータをやり取りし、液晶パネルに信号を印加している。
ソースドライバーから印加した信号は、ゲートドライバ
ーの信号でＯＮ状態になったＴＦＴ素子を介して、液晶
層３３、および補助容量３４へ印加され、ＴＦＴがオフ
状態になると液晶層の容量成分３３ｃと補助容量３４で
蓄えた電荷が、液晶層３３の抵抗成分３３ｒを通じて徐
々に放電される。液晶材料の抵抗値によって放電の時定
数が異なるが、抵抗の高いフッ素系材料でも、６０Ｈｚ
以上の書き換えを行わなければフリッカーが生じる。そ
のため、ＲＡＭ内蔵ドライバー内部ではＲＡＭとソース
ドライバー間で６０Ｈｚ以上のデータのやり取りが生ず
るが、ＬＳＩ間でデータをやり取りする場合に比べ、Ｌ
ＳＩ内部ではＲＡＭとソースドライバーの配線が短く、
消費電力を増やす容量が小さくなるため、電力を小さく
することができる。In mobile phones and OA equipment, the display screen displays a still image for most of the time, and it is not necessary to update the display screen, but in order to avoid flicker, it is necessary to continue driving even in the still image display. . Therefore, in order to suppress the power consumption due to the transfer of the image memory as described above when displaying a still image, a RAM built-in driver having an image memory built in the driver LSI is commercially available, and as shown in FIG. It constitutes a display element. The RAM built-in driver 30 is a source driver 3 that drives the liquid crystal.
1 has a RAM 32 inside the LSI, and when the screen contents are not rewritten, data is exchanged inside the RAM built-in driver 30 and a signal is applied to the liquid crystal panel.
The signal applied from the source driver is applied to the liquid crystal layer 33 and the auxiliary capacitance 34 via the TFT element turned on by the signal of the gate driver, and when the TFT is turned off, the capacitance component 33c of the liquid crystal layer and the auxiliary component are added. The electric charge stored in the capacitor 34 is gradually discharged through the resistance component 33r of the liquid crystal layer 33. The discharge time constant varies depending on the resistance value of the liquid crystal material, but even with high resistance fluorine-based materials, 60 Hz
If the above rewriting is not performed, flicker occurs. Therefore, data exchange of 60 Hz or more occurs between the RAM and the source driver inside the driver with built-in RAM, but compared to the case of exchanging data between LSIs, L
Wiring between RAM and source driver is short inside SI,
Since the capacity for increasing the power consumption is reduced, the power can be reduced.
【０００５】[0005]
【発明が解決しようとする課題】メモリー内蔵ドライバ
ーは、低消費電力化に有効であるが、ＬＳＩのチップ面
積が大きくコストが高い。ドライバーＬＳＩは液晶を駆
動するための電圧が液晶ＤＲＡＭなどと比べて高い為
に、耐圧の高い、加工ルールの比較的大きなプロセスで
ＬＳＩを作成するため、大容量の画像メモリーをＬＳＩ
内に入れると、ＤＲＡＭを別に作る場合と比べてチップ
が大きくなってしまう。The driver with a built-in memory is effective in reducing power consumption, but the LSI chip area is large and the cost is high. Since the driver LSI has a higher voltage for driving the liquid crystal than a liquid crystal DRAM, etc., a large-capacity image memory is used for the LSI because the LSI is created by a process with a high breakdown voltage and a relatively large processing rule.
If you put it inside, the chip becomes larger than if you make a separate DRAM.
【０００６】[0006]
【課題を解決するための手段】上記の課題を解決するた
めに、本発明の液晶表示素子は、画像情報に応じた信号
電圧を蓄積する蓄積部と、蓄積された信号電圧に応じて
液晶層への印加電圧を変調する変調回路とを、画素毎に
具備することを特徴とし、好ましくは、変調回路が、蓄
積部で蓄積された信号電圧に応じて、所定の周波数の発
振電圧を振幅変調することを特徴とすることにより、ド
ライバーＬＳＩからの書き換え周波数を極端に低くして
も液晶層への印加電圧は所定の周波数、例えば６０Ｈｚ
に保たれるためフリッカーは生じず、低消費電力でも表
示品位を損なわず、ドライバーLSI内にメモリーが不要
なのでコストも安い。蓄積部がコンデンサーと、信号電
圧を印加するアクティブ素子からなることにより画素を
駆動するＴＦＴ素子と同時に蓄積部を作成できる。ま
た、所定の周波数の発振電圧を出力する発振回路を具備
することにより、外部からの入力は通常の信号入力のみ
にもできる。また、画像が静止画のとき、動画表示のと
きより蓄積容量へ電圧を印加する走査周期を遅くして消
費電力を小さくできる。なお、アクティブ素子として、
ＴＦＴ素子やスイッチング素子を用いることができる。In order to solve the above-mentioned problems, a liquid crystal display device of the present invention comprises a storage section for storing a signal voltage according to image information, and a liquid crystal layer according to the stored signal voltage. A modulation circuit that modulates a voltage applied to the pixel is provided for each pixel. Preferably, the modulation circuit amplitude-modulates an oscillation voltage of a predetermined frequency according to the signal voltage accumulated in the accumulator. By so doing, even if the rewriting frequency from the driver LSI is extremely lowered, the voltage applied to the liquid crystal layer has a predetermined frequency, for example, 60 Hz.
Since it is kept at flicker, flicker does not occur, the display quality is not impaired even with low power consumption, and the cost is low because no memory is required in the driver LSI. Since the storage unit includes the capacitor and the active element that applies the signal voltage, the storage unit can be formed at the same time as the TFT element that drives the pixel. Further, by providing an oscillation circuit that outputs an oscillation voltage of a predetermined frequency, the external input can be only a normal signal input. Further, when the image is a still image, the power consumption can be reduced by delaying the scanning cycle for applying a voltage to the storage capacitor as compared with the case of displaying a moving image. As an active element,
A TFT element or a switching element can be used.
【０００７】画像情報に応じた信号電圧を蓄積する蓄積
部と、蓄積された信号電圧に応じて液晶層への印加電圧
を変調する変調回路とを、画素毎に具備すること液晶表
所素子の駆動方法において、前記蓄積部への信号電圧の
書き込み周波数を６０Ｈｚ未満とすることを特徴とする
液晶表示素子の駆動方法により、低消費電力でもフリッ
カーのない表示が可能になる。書き込み周波数が３０ヘ
ルツ未満にすると、さらに低電力化できる。For each pixel, a storage unit for storing a signal voltage corresponding to image information and a modulation circuit for modulating the voltage applied to the liquid crystal layer according to the stored signal voltage are provided. In the driving method, the liquid crystal display element driving method is characterized in that the writing frequency of the signal voltage to the storage unit is set to less than 60 Hz, which enables display without flicker even with low power consumption. When the writing frequency is less than 30 hertz, the power consumption can be further reduced.
【０００８】[0008]
【発明の実施の形態】（実施の形態１）図１は、本発明
の液晶表示素子の等価回路図を表す。ソース側入力端子
１に画像信号液晶層１は等価回路として容量と抵抗の並
列回路で示している外部ソース側入力端子１にソースド
ライバーＬＳＩから画像信号２を入力し、ゲート配線３
がオン状態になると、液晶表示素子の画素毎に設けられ
たＴＦＴ素子４が短絡状態になり蓄積部５に電荷が貯め
られ信号電圧が記憶される。ゲート３がオフになるとＴ
ＦＴ素子４はオープン状態になり、かつ振幅変調回路６
の入力インピーダンスも高いので蓄積部５に貯められた
電荷はほとんど放電しない。画素毎に設けられた振幅変
調回路６に、蓄積部５で記憶された電圧Ｖsと外部から
入力した、もしくは表示素子の周辺回路から与えた所定
の発振電圧Ｖｈ（例えば６０Ｈｚで振幅が１０Ｖ）を入
力すると、出力として発振電圧Ｖｈが振幅変調されたＶ
outが液晶層７に印加される。発振電圧Ｖhの周波数はフ
リッカーを生じないように６０Ｈz以上としておけば、
液晶層は発振周波数の交流信号で駆動され、フリッカー
はほとんど生じない。静止画表示のときには、画像信号
の書き換え周波数を、数Ｈｚあるいは数Ｈｚ以下のフリ
ッカーを感じにくい低周波数とするのが、よりフリッカ
ーを抑えるためには好ましい。一方、動画駆動の時には
画像信号の書き換えは６０Ｈｚまたは３０Ｈｚ以上とし
てフリッカーのない滑らかな動きを再現するのがよく、
画像が静止画が動画かによって駆動方法を切り替えるの
がよい。DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG. 1 shows an equivalent circuit diagram of a liquid crystal display device of the present invention. The image signal liquid crystal layer 1 is input to the source side input terminal 1 and the image signal 2 is input from the source driver LSI to the external source side input terminal 1 shown as a parallel circuit of capacitance and resistance as an equivalent circuit.
When is turned on, the TFT element 4 provided for each pixel of the liquid crystal display element is in a short-circuited state, and the charge is stored in the accumulating portion 5 and the signal voltage is stored. T when gate 3 turns off
The FT element 4 is in an open state, and the amplitude modulation circuit 6
Has a high input impedance, the electric charge stored in the storage unit 5 is hardly discharged. A voltage Vs stored in the storage unit 5 and a predetermined oscillation voltage Vh (for example, an amplitude of 10 V at 60 Hz) input from the outside or applied from a peripheral circuit of the display element are input to the amplitude modulation circuit 6 provided for each pixel. When input, the oscillation voltage Vh is output as the amplitude-modulated V
out is applied to the liquid crystal layer 7. If the frequency of the oscillating voltage Vh is set to 60 Hz or higher so that flicker does not occur,
The liquid crystal layer is driven by an AC signal having an oscillation frequency, and flicker hardly occurs. When displaying a still image, it is preferable to set the rewriting frequency of the image signal to a low frequency of several Hz or less than several Hz so that flicker is less likely to be felt in order to further suppress flicker. On the other hand, when driving a moving image, it is preferable to rewrite the image signal at 60 Hz or 30 Hz or higher to reproduce smooth motion without flicker.
It is better to switch the driving method depending on whether the image is a still image.
【０００９】発振電圧は、表示素子の外部から入力して
もよいが、表示素子上のＬＳＩや回路部品に発振回路を
内蔵し、ドライバーＬＳＩのクロックと同期を取るの
が、実装部分がよりコンパクトになって望ましい。The oscillating voltage may be input from the outside of the display element, but it is more compact to mount it by incorporating an oscillating circuit in the LSI or circuit parts on the display element and synchronizing it with the clock of the driver LSI. Is desirable.
【００１０】従来は、図３のように信号電圧を蓄積して
いた補助容量３４と液晶層の容量成分３３ｃから、電荷
が液晶層の抵抗成分３３ｒを通って流れてしまい、蓄積
していた電圧が減衰してしまっていた。液晶層の抵抗値
は、ＴＦＴ液晶で用いられる抵抗の高いフッ素系液晶で
も組成物のボトル内の抵抗値で凡そ１０13Ω・ｃｍであ
るが実際のパネル内では、不純物によりかなり抵抗値が
下がることが知られている。液晶層の膜厚が数μｍ、画
素電極の大きさが３００×１００μｍとすると、パネル
内の液晶層の抵抗値は１０13Ωより小さい。一方、ＴＦ
Ｔ素子がオープン状態になったときのオフ抵抗は、１０
14Ω程度で、１桁以上大きい。このため本発明では、信
号電圧を蓄積した蓄積部５１の電荷は、従来構成と比べ
て減衰が遅く、数Ｈｚ未満の遅い周波数で書き換えを行
ったとしても蓄積した電圧Ｖｓはほぼ保たれる。In the prior art, from the auxiliary capacitance 34 and the capacitance component 33c of the liquid crystal layer, which stored the signal voltage as shown in FIG. 3, charges flowed through the resistance component 33r of the liquid crystal layer, and the accumulated voltage was stored. Was attenuated. The resistance value of the liquid crystal layer is about 10 13 Ω · cm in the bottle of the composition even with the fluorine-based liquid crystal having high resistance used in the TFT liquid crystal, but in the actual panel, the resistance value is considerably lowered by impurities. It is known. When the thickness of the liquid crystal layer is several μm and the size of the pixel electrode is 300 × 100 μm, the resistance value of the liquid crystal layer in the panel is smaller than 10 13 Ω. On the other hand, TF
The off resistance when the T element is in the open state is 10
It is about 14 Ω, which is more than one digit. Therefore, in the present invention, the charge of the storage unit 51 that has stored the signal voltage is attenuated more slowly than in the conventional configuration, and the stored voltage Vs is substantially maintained even when rewriting is performed at a slow frequency of less than several Hz.
【００１１】図１の振幅変調回路は、図２のような論理
回路で実現できる。すなわち、発振電圧Ｖｈと蓄積され
た画像信号Ｖｓの論理積を、発振電圧Ｖｈと共に論理和
へ入力すればよい。他にも、振幅変調回路の構成はある
のでこれに限らない。また、振幅変調以外にも、例えば
周波数で誘電異方性が変わる二周波液晶材料などを使え
ば、出力の周波数を蓄積したＶｓに応じて変える周波数
変調でも液晶層を駆動でき、同様の作用、効果がある。The amplitude modulation circuit of FIG. 1 can be realized by a logic circuit as shown in FIG. That is, the logical product of the oscillation voltage Vh and the accumulated image signal Vs may be input to the logical sum together with the oscillation voltage Vh. Since there is another configuration of the amplitude modulation circuit, the configuration is not limited to this. In addition to amplitude modulation, for example, if a dual frequency liquid crystal material whose dielectric anisotropy changes with frequency is used, the liquid crystal layer can be driven by frequency modulation in which the output frequency is changed according to the accumulated Vs, and the same action, effective.
【００１２】また、本実施の形態では、液晶表示素子に
ついて詳述したが、液晶以外にも交流駆動が必要なアク
ティブ素子駆動する素子なら同様の効果が期待できる。Further, although the liquid crystal display element has been described in detail in the present embodiment, the same effect can be expected if an element other than the liquid crystal element that drives an active element that requires AC driving.
【００１３】以上のように本発明の液晶表示素子を用い
れば、通常の安価なドライバーＬＳＩを用いても、ＲＡ
Ｍ内蔵ドライバーのように消費電力を非常に小さくする
ことが可能であった。このような液晶表示素子携帯電話
や携帯情報端末のように、蓄電池で駆動する携帯型の電
子機器では、本発明の表示素子を用いて、静止画表示の
時には、駆動周波数を落とす駆動回路を具備すること
で、消費電力の極めて小さい表示装置が実現でき、バッ
テリー寿命を延ばすことができる。しかし、一方で、動
画表示のときには、滑らかな動きを表現するために、書
き込み周波数は６０Ｈｚ以上であることが望ましいの
で、静止画と動画で書き換え周波数を変えなければなら
ない。表示装置側で、画像情報から、動画か静止画かを
判断するのは、その判定のために回路が複雑化し、電力
が増えてしまう。従って、電子機器側に、画像情報と同
時に、動画と静止画を判別できるフラッグ信号を送る信
号伝送回路が備わっていることが好ましい。次世代の携
帯電話などで、今後使用される情報圧縮方式の国際標準
規格であるＭＰＥＧ４では、動きに対する情報が含まれ
ており、静止画か、動画かをＣＰＵ側で容易に判断でき
るので、このようなフラッグ信号を表示素子の表示装置
に送ることで、静止画での低電力化と、滑らかな動画へ
の切り替えがスムーズに行える。As described above, when the liquid crystal display element of the present invention is used, RA is used even if an ordinary inexpensive driver LSI is used.
It was possible to reduce the power consumption to a very low level as with the driver with built-in M. In a portable electronic device driven by a storage battery, such as a liquid crystal display device mobile phone or a mobile information terminal, the display device of the present invention is used to provide a drive circuit for reducing the drive frequency when displaying a still image. By doing so, a display device with extremely low power consumption can be realized and battery life can be extended. However, on the other hand, when displaying a moving image, it is desirable that the writing frequency is 60 Hz or higher in order to express a smooth motion, so the rewriting frequency must be changed between the still image and the moving image. When the display device determines from the image information whether it is a moving image or a still image, the circuit is complicated due to the determination, and the power increases. Therefore, it is preferable that the electronic device is equipped with a signal transmission circuit that sends a flag signal that can distinguish a moving image from a still image at the same time as the image information. In next-generation mobile phones, MPEG4, which is an international standard of information compression method that will be used in the future, contains information about motion, and the CPU side can easily determine whether it is a still image or a moving image. By sending such a flag signal to the display device of the display element, it is possible to reduce the power consumption of a still image and smoothly switch to a moving image.
【００１４】[0014]
【発明の効果】本発明の液晶表示装置は、画像情報に応
じた信号電圧を蓄積する蓄積部と、蓄積された信号電圧
に応じて液晶層への印加電圧を変調する変調回路、例え
ば振幅変調回路を、画素毎に具備することにより、ドラ
イバーＬＳＩからの書き込みが低周波数であってもフリ
ッカーが見え難く、低消費電力で品位の高い画像を表示
することができる。According to the liquid crystal display device of the present invention, a storage section for storing a signal voltage corresponding to image information and a modulation circuit for modulating a voltage applied to a liquid crystal layer in accordance with the stored signal voltage, for example, amplitude modulation. By providing a circuit for each pixel, it is possible to display a high-quality image with low power consumption and with less flicker even if writing from the driver LSI has a low frequency.
【図１】本発明の液晶表示素子の等価回路図FIG. 1 is an equivalent circuit diagram of a liquid crystal display device of the present invention.
【図２】本発明の液晶表示素子の等価回路図FIG. 2 is an equivalent circuit diagram of the liquid crystal display element of the present invention.
【図３】従来の液晶表示素子の等価回路図FIG. 3 is an equivalent circuit diagram of a conventional liquid crystal display device.
１ 外部ソース側入力端子 ２ 画像信号 ３ ゲート配線 ４ ＴＦＴ素子 ５ 蓄積部 ６ 振幅変調回路 ７ 液晶層 ３０ ＲＡＭ内臓ドライバー ３１ ソースドライバー ３２ ＲＡＭ ３３ 液晶層 ３３ｃ 容量成分 ３３ｒ 抵抗成分 ３４ 補助容量 1 External source side input terminal 2 image signals 3 gate wiring 4 TFT element 5 Storage 6 Amplitude modulation circuit 7 Liquid crystal layer 30 RAM built-in driver 31 Source Driver 32 RAM 33 Liquid crystal layer 33c Capacity component 33r Resistance component 34 Auxiliary capacity
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｇ０９Ｇ 3/20 ６４１ Ｇ０９Ｇ 3/20 ６４１Ｃ Ｆターム(参考） 2H093 NA16 NA34 NA53 NC13 NC26 NC28 NC34 ND39 5C006 AA16 AC21 BB16 BC06 BC12 EB05 FA23 FA44 FA46 FA47 FA51 5C080 AA10 BB05 DD06 DD22 DD25 DD26 DD27 FF11 JJ02 ─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. 7 Identification code FI theme code (reference) G09G 3/20 641 G09G 3/20 641C F term (reference) 2H093 NA16 NA34 NA53 NC13 NC26 NC28 NC34 ND39 5C006 AA16 AC21 BB16 BC06 BC12 EB05 FA23 FA44 FA46 FA47 FA51 5C080 AA10 BB05 DD06 DD22 DD25 DD26 DD27 FF11 JJ02
Claims (9)
査信号が入力される複数の走査線と、前記信号線と前記
走査線の交差点に対応して、液晶層を有する画素と、前
記画素毎にアクティブ素子、画像情報に応じた信号電圧
を蓄積する蓄積部及び蓄積された信号電圧に応じて液晶
層への印加電圧を変調する変調回路とを有し、前記信号
線が前記アクティブ素子を介して前記変調回路の入力端
子に接続され、前記変調回路の出力端子に前記画素が接
続され、前記変調回路の入力端子に前記蓄積部が接続さ
れていることを特徴とする液晶表示素子。1. A plurality of signal lines to which an image signal is input, a plurality of scanning lines to which a scanning signal is input, a pixel having a liquid crystal layer corresponding to an intersection of the signal line and the scanning line, An active element for each pixel, an accumulating section for accumulating a signal voltage according to image information, and a modulation circuit for modulating an applied voltage to the liquid crystal layer according to the accumulated signal voltage, and the signal line is the active element. A liquid crystal display element, characterized in that the liquid crystal display device is connected to the input terminal of the modulation circuit, the pixel is connected to the output terminal of the modulation circuit, and the storage section is connected to the input terminal of the modulation circuit.
積部と、蓄積された信号電圧に応じて液晶層への印加電
圧を変調する変調回路とを、画素毎に具備することを特
徴とする液晶表示素子。2. A storage unit for storing a signal voltage according to image information and a modulation circuit for modulating a voltage applied to a liquid crystal layer according to the stored signal voltage are provided for each pixel. Liquid crystal display device.
圧に応じて、所定の周波数の発振電圧を振幅変調するこ
とを特徴とする請求項１又は２記載の液晶表示素子。3. The liquid crystal display element according to claim 1, wherein the modulation circuit amplitude-modulates the oscillation voltage of a predetermined frequency according to the signal voltage accumulated in the accumulator.
回路を具備する請求項３記載の液晶表示素子。4. The liquid crystal display element according to claim 3, further comprising an oscillation circuit that outputs an oscillation voltage of a predetermined frequency.
り蓄積容量へ電圧を印加する走査周期を遅くしたことを
特徴とする請求項１又は２記載の液晶表示素子。5. The liquid crystal display element according to claim 1, wherein when the image is a still image, the scanning cycle for applying a voltage to the storage capacitor is made slower than when a moving image is displayed.
信号電圧をコンデンサからなる蓄積部へ印加するアクテ
ィブ素子と、蓄積部で蓄積された信号電圧に応じて所定
の周波数の発振電圧を振幅変調する変調回路を具備する
ことを特徴とする液晶表示素子用基板。6. An active element for applying a source signal voltage to a storage section formed of a capacitor in synchronization with a gate signal for each pixel, and an oscillation voltage having a predetermined frequency according to the signal voltage stored in the storage section. A substrate for a liquid crystal display device, comprising a modulation circuit for modulating.
積するステップと、蓄積された信号電圧に応じて液晶層
への印加電圧を変調するステップとを具備する液晶表示
素子の駆動方法において、前記蓄積部への前記信号電圧
の書き込み周波数を６０Ｈｚ未満とすることを特徴とす
る液晶表示素子の駆動方法。7. A method of driving a liquid crystal display device, comprising: a step of accumulating a signal voltage corresponding to image information in an accumulating section; and a step of modulating an applied voltage to a liquid crystal layer according to the accumulated signal voltage. A driving method of a liquid crystal display device, wherein a writing frequency of the signal voltage to the storage unit is set to less than 60 Hz.
積部と、蓄積された信号電圧に応じて液晶層への印加電
圧を変調する変調回路とを、画素毎に具備することを特
徴とする液晶表示素子と、蓄積容量への書き込み周波数
を、画像情報に応じてかえる駆動回路とを具備すること
を特徴とする表示装置。8. A storage unit for storing a signal voltage according to image information, and a modulation circuit for modulating a voltage applied to a liquid crystal layer according to the stored signal voltage are provided for each pixel. A display device comprising: a liquid crystal display element for controlling a storage capacity; and a drive circuit for changing a writing frequency to a storage capacitor according to image information.
積部と、蓄積された信号電圧に応じて液晶層への印加電
圧を変調する変調回路とを、画素毎に具備することを特
徴とする液晶表示素子と、画像情報を、静止画か動画か
を示すフラッグ信号と共に送る信号処理回路とを有し、
フラッグ信号が静止画の状態を示すときに、前記画像情
報の表示素子への書き込み周波数を、動画の時より遅く
することを特徴とする電子機器。9. A storage unit for storing a signal voltage according to image information, and a modulation circuit for modulating a voltage applied to a liquid crystal layer according to the stored signal voltage are provided for each pixel. And a signal processing circuit that sends image information together with a flag signal indicating whether a still image or a moving image,
An electronic device, characterized in that, when the flag signal indicates a still image state, the writing frequency of the image information to the display element is made slower than that of a moving image.
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| JP2001240784A JP2003058114A (en) | 2001-08-08 | 2001-08-08 | Liquid crystal display element and its driving method |
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| JP2001240784A JP2003058114A (en) | 2001-08-08 | 2001-08-08 | Liquid crystal display element and its driving method |
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| CN102667910A (en) * | 2009-12-18 | 2012-09-12 | 株式会社半导体能源研究所 | Liquid crystal display device and electronic device |
| JP2014521168A (en) * | 2011-07-12 | 2014-08-25 | クゥアルコム・インコーポレイテッド | Still image display |
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2001
- 2001-08-08 JP JP2001240784A patent/JP2003058114A/en active Pending
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