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WO2000013057A1 - Ecran a cristaux liquides et procede de pilotage dudit ecran - Google Patents

Ecran a cristaux liquides et procede de pilotage dudit ecran Download PDF

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Publication number
WO2000013057A1
WO2000013057A1 PCT/JP1998/003859 JP9803859W WO0013057A1 WO 2000013057 A1 WO2000013057 A1 WO 2000013057A1 JP 9803859 W JP9803859 W JP 9803859W WO 0013057 A1 WO0013057 A1 WO 0013057A1
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WO
WIPO (PCT)
Prior art keywords
liquid crystal
state
period
ferroelectric
light
Prior art date
Application number
PCT/JP1998/003859
Other languages
English (en)
Japanese (ja)
Inventor
Shinya Kondoh
Mie Ohara
Original Assignee
Citizen Watch Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Citizen Watch Co., Ltd. filed Critical Citizen Watch Co., Ltd.
Priority to EP98940621A priority Critical patent/EP1028347A4/fr
Priority to PCT/JP1998/003859 priority patent/WO2000013057A1/fr
Publication of WO2000013057A1 publication Critical patent/WO2000013057A1/fr

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Classifications

    • 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
    • G09G3/3622—Control of matrices with row and column drivers using a passive matrix
    • G09G3/3629—Control of matrices with row and column drivers using a passive matrix using liquid crystals having memory effects, e.g. ferroelectric liquid crystals
    • 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
    • G09G3/3406—Control of illumination source
    • 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
    • G09G3/3622—Control of matrices with row and column drivers using a passive matrix
    • G09G3/3629—Control of matrices with row and column drivers using a passive matrix using liquid crystals having memory effects, e.g. ferroelectric liquid crystals
    • G09G3/3633—Control of matrices with row and column drivers using a passive matrix using liquid crystals having memory effects, e.g. ferroelectric liquid crystals with transmission/voltage characteristic comprising multiple loops, e.g. antiferroelectric liquid crystals
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0235—Field-sequential colour display
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/06—Details of flat display driving waveforms
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/06—Details of flat display driving waveforms
    • G09G2310/061—Details of flat display driving waveforms for resetting or blanking
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/06—Details of flat display driving waveforms
    • G09G2310/061—Details of flat display driving waveforms for resetting or blanking
    • G09G2310/063—Waveforms for resetting the whole screen at once
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/06—Details of flat display driving waveforms
    • G09G2310/065—Waveforms comprising zero voltage phase or pause
    • 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

Definitions

  • the present invention relates to a liquid crystal display panel having a matrix-shaped pixel having an antiferroelectric liquid crystal and a ferroelectric liquid crystal as a liquid crystal layer, a liquid crystal optical shutter, or the like, which emits a plurality of colors.
  • BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates to a liquid crystal display and a method of driving the liquid crystal display, which are combined with a light source capable of performing the operation. Background art
  • a liquid crystal cell is used as a shutter, and a light emitting element (eg,
  • the light transmittance of the liquid crystal cell is 50% while R emits time TS light
  • the light transmittance of the liquid crystal cell is 70% while G emits time TS light
  • B is light transmittance.
  • the light transmittance of the liquid crystal cell is 90%.
  • each color is not recognized as a single color, but is recognized by humans as a mixture of the respective colors.
  • a liquid crystal display device using an anti-ferroelectric liquid crystal is disclosed in Japanese Patent Application Laid-Open No. 2-173732 of Nippon Denso Co., Ltd. and Showa Shell Sekiyu KK. Responsiveness and good multiplex properties have been reported, and research has been conducted energetically.
  • the pixel immediately before writing to the pixel, the pixel is forcibly reset to a black display state or a white display state regardless of display data. This is generally performed.
  • a reset period (R e) is provided immediately before the selection period (S e), and a voltage lower than the threshold voltage is applied to the pixel during this period. Applied and reset to an antiferroelectric state.
  • R e reset period
  • S e selection period
  • the antiferroelectric liquid crystal has a plurality of stable states, it is considered that the state of the liquid crystal molecules differs depending on the immediately preceding display state as another factor. Since the threshold value when a voltage is applied differs depending on the stable state of the molecule, if all molecules do not have the same stable state immediately before the selection period, all pixels are the same as the voltage applied during the selection period. It is difficult to control the display state.
  • an object of the present invention to provide an antiferroelectric liquid crystal display and a ferroelectric liquid crystal display using a successive addition phenomenon, and a method of driving them.
  • a liquid crystal display display capable of uniformly displaying an excellent display on the entire panel and a driving method thereof. The purpose is to: Disclosure of the invention
  • an antiferroelectric liquid crystal display comprises an antiferroelectric liquid crystal display in which an antiferroelectric liquid crystal is sandwiched between a pair of substrates having pixels in a matrix form.
  • Device and a light source that sequentially emits light of different colors from each other.
  • the light source has an arbitrary period during which light emission stops while the color of light changes
  • the antiferroelectric liquid crystal of all pixels is provided with an antiferroelectric liquid crystal in a first period or a last period of a period in which light of an arbitrary color of the light source emits light. Simultaneously reset to one of the dielectric state, the first ferroelectric state, or the second ferroelectric state 98/03859 reset period.
  • the ferroelectric liquid crystal display of the present invention comprises a ferroelectric liquid crystal display element in which a ferroelectric liquid crystal is sandwiched between a pair of substrates having pixels in a matrix, and light of different colors. It has a light source that emits light over time,
  • the light source has an arbitrary period during which light emission stops while the color of light changes
  • the ferroelectric liquid crystal of all the pixels is in the first period or the last period of the period in which light of any color of the light source is emitting. Has a reset period that is simultaneously reset to either the first stable state or the second stable state o
  • a voltage for determining a display state of a pixel is applied in a selection period within a period in which light of an arbitrary color of the light source emits light, and the display state is maintained in a subsequent non-selection period.
  • the method of driving the antiferroelectric liquid crystal display of the present invention is described in T / JP98 / 03859
  • the antiferroelectric liquid crystal of all pixels is set to the antiferroelectric state and the first ferroelectric state during the first period or the last period of light emission of an arbitrary color of the light source. , Or the second ferroelectric state at the same time.
  • the method of driving a ferroelectric liquid crystal display according to the present invention includes: stopping light emission for an arbitrary period while the light source changes the color of light;
  • FIG. 1 is a configuration diagram of an antiferroelectric liquid crystal cell and a polarizing plate of the present invention.
  • FIG. 2 is a diagram showing a hysteresis curve of the antiferroelectric liquid crystal display device of the present invention.
  • FIG. 3 is a diagram showing a matrix electrode.
  • FIG. 4 is a diagram showing a driving waveform of a conventional antiferroelectric liquid crystal display and a corresponding light transmittance.
  • FIG. 5 is a configuration diagram of the ferroelectric liquid crystal cell and the polarizing plate of the present invention.
  • FIG. 6 is a diagram illustrating a hysteresis curve of the ferroelectric liquid crystal display device of the present invention.
  • FIG. 8 is a panel configuration diagram of the liquid crystal panel of the present invention.
  • FIG. 11 is a diagram showing driving waveforms of another embodiment of the present invention in the case of an antiferroelectric liquid crystal.
  • FIG. 13 is a diagram showing driving waveforms of the embodiment of the present invention in the case of a ferroelectric liquid crystal.
  • FIG. 14 is a diagram showing driving waveforms of another embodiment of the present invention in the case of a ferroelectric liquid crystal.
  • V 1 the voltage value at which the light transmittance starts to change
  • V 2 the voltage value at which the change in light transmittance saturates
  • V 3 the voltage value at which the light transmittance begins to change when the absolute value is increased and the absolute value of the voltage is increased
  • V 4 is the voltage value at which the light transmittance starts to change when the absolute value of the voltage is reduced.
  • the first ferroelectric state is selected when the applied voltage value is equal to or higher than the threshold of the antiferroelectric liquid crystal molecules.
  • the second ferroelectric state is selected.
  • the antiferroelectric state is selected.
  • FIG. 3 shows the matrix of scanning electrodes and signal electrodes on a substrate.
  • FIG. 3 is a diagram illustrating an example of an electrode configuration of a liquid crystal panel arranged.
  • This electrode configuration has scan electrodes (X1, X2, X3, Xn, --XI00) and signal electrodes (Yl, ⁇ 2, ⁇ 3, -Ym, --Y220).
  • the hatched portion where the scanning electrode and the signal electrode intersect is the pixel (A11, Anm).
  • a voltage is applied to the scan electrode corresponding to each of the pixels, and a voltage waveform corresponding to the display state is applied from the signal electrode in synchronization with the voltage.
  • the display is written according to the composite waveform of the voltage waveforms of the signal electrode and the scanning electrode.
  • the scanning voltage (a) is applied to the scanning electrode (Xn), the signal voltage (b) is applied to the signal electrode (Ym), and the combined voltage (c) is applied to the pixel (Anm).
  • Writing to the pixel is performed by applying the voltage.
  • the first ferroelectric state, the second ferroelectric state, or the antiferroelectric state is selected during the selection period (S e), and the state is changed to the next non-selection period (NS e). Is held. That is, the selection pulse is applied during the selection period (S e), and the resulting transmittance (d) is compared with the subsequent non-selection period.
  • N Se N Se
  • the antiferroelectric liquid crystal must be reset to a first ferroelectric state, a second ferroelectric state, or an antiferroelectric state immediately before writing to a pixel. Is generally performed. In Figure 4, the selection period
  • a reset period (R e) is provided immediately before (S e). During this period, a voltage lower than the threshold voltage is applied to the pixels, and the antiferroelectric liquid crystal is reset to the antiferroelectric state.
  • R e a voltage lower than the threshold voltage
  • the antiferroelectric liquid crystal is reset to the antiferroelectric state.
  • Figure 5 shows the arrangement of polarizing plates when a ferroelectric liquid crystal is used as a liquid crystal display device.
  • FIG. Between the polarizers 1a and 1b aligned with the cross Nicol, either one of the polarization axis a of the polarizer 1a or the polarization axis b of the polarizer 1b and the first stable state of the liquid crystal molecules should be provided. Plots the liquid crystal cell 2 so that it is almost parallel to either of the molecular long axes in the second stable state. When a voltage is applied to such a liquid crystal cell, the change in transmittance with respect to that is plotted. Then draw a loop as shown in Figure 6.
  • black display (non-transmission state) in the first stable state and white display (transmission state) in the second stable state can be performed.
  • white display (transmission state) can be performed in the first stable state
  • black display (non-transmission state) can be performed in the second stable state.
  • black is displayed (non-transmissive state) in the first stable state and white (transparent state) is displayed in the second stable state.
  • FIG. 3 is a diagram showing an example of an electrode configuration of a liquid crystal panel in which scanning electrodes and signal electrodes are arranged in a matrix on a substrate, as described above.
  • a voltage is applied line by line to the scanning electrodes corresponding to the pixels shown in Fig. 3, and in synchronism with this, a voltage wave corresponding to the display state is applied from the signal electrodes. Shape is applied.
  • the display is written according to the composite waveform of the voltage waveforms of the signal electrode and the scanning electrode.
  • Figure 7 shows an example of a general driving waveform of a ferroelectric liquid crystal display.
  • the scanning voltage (a) is applied to the scanning electrode (X n)
  • the signal voltage (b) is applied to the signal electrode (Y m)
  • the combined voltage (c) is applied to the pixel (A nm)
  • Writing to the pixel is performed.
  • (d) represents the light transmittance of the waveform.
  • a pulse P1 having a peak value + Vp and a pulse width T equal to or greater than the threshold, and a pulse having a peak value 1 Vp and a pulse width T equal to or greater than the threshold value Apply P 2 to the pixels of the liquid crystal.
  • the first half pulse p 1 is in the direction of switching the liquid crystal molecules from the second stable state (white display) to the first stable state (black display)
  • the second half pulse P 2 has the opposite polarity. And performs switching in the reverse direction from the first stable state to the second stable state. Therefore, the state switched by the pulse P 1 is not maintained, and the second stable state switched by the pulse P 2 is maintained.
  • the pulse applied to the pixel is below the threshold, so that the second stable state obtained earlier is maintained and the light transmittance is maintained at the same value.
  • the pulse applied to the pixel in the next non-selection period (NSe 2) is also equal to or smaller than the threshold, so that the first stable state (black display) obtained earlier is maintained.
  • a reset period (R e2) is provided after the non-selection period (NS e 2), and a pulse P 7 having a peak value of 1 V p or more above the threshold and a pulse having a peak value of + V p above the threshold value P 8 is applied to the liquid crystal pixels. Since the pulse P7 in the first half is in the direction of switching from the first stable state (black display) to the second stable state (white display), the light transmittance increases. However, the pulse P 8 in the latter half has the opposite polarity and switches from the second stable state (white display) to the first stable state (black display), so that the light transmittance is almost zero. Fall to 0. During this time, the light transmittance rises momentarily, but falls immediately and is not recognized by the human eye.
  • the RGB light source is turned on for an arbitrary time in order, and the time during which the RGB light is turned on (one cycle) and the period required to write the necessary information to one pixel Becomes
  • the display state of the pixel is changed.
  • a selection period in which the voltage for determining the state is applied and a non-selection period in which the display state is maintained are provided in each time when the light source of each color is lit. That is, when light sources of three colors R, G, and B are used, a reset period, a selection period, and a non-selection period are provided for each of the periods in which R, G, and B are turned on.
  • an arbitrary period is set between the colors of the light emitted by the light source, and the light emission is stopped only during this period.
  • the antiferroelectric liquid crystal of all the pixels is replaced with the first ferroelectric liquid crystal.
  • the ferroelectric liquid crystal is reset to the first stable state or the second stable state. That is, the reset period is set so as to overlap with an arbitrary period in which light emission is stopped.
  • a similar effect is achieved by providing a reset period for simultaneously resetting the antiferroelectric liquid crystal or ferroelectric liquid crystal of all pixels in the last period when a light source of a certain color stops emitting light. Can also be obtained. Even if the reset period is set to the last period in which the light source stops emitting light, all pixels are reset at the same time, so that the number of resets can be minimized. Further, the selection period and the non-selection period can be set continuously to the period in which the light source of an arbitrary color emits light. Therefore, the light emission time of the light source while the necessary display is being written can be lengthened, and good display can be performed.
  • FIG. 8 is a configuration diagram of a liquid crystal panel used in an example of the present invention.
  • the liquid crystal panel used in the present embodiment is formed by bonding a pair of glass substrates 11a and 11b having an antiferroelectric liquid crystal or a ferroelectric liquid crystal layer 10 having a thickness of about 2 to two glasses. It is composed of seal materials 12a and 12b. Electrodes (ITO) 13a and 13b are formed on the opposite surface of the glass substrate, and alignment films 14a and 14b are applied thereon, and an alignment process is performed.
  • ITO Electrodes
  • a first polarizing plate 15a is provided outside one of the glass substrates so that the polarization axis and the orientation axis of the polarizing plate are parallel to each other, and the first polarizing plate 15a is provided outside the other glass substrate.
  • the second polarizing plate 15b is provided so as to be 90 ° different from the polarizing axis of the first polarizing plate 15a.
  • LEDs that emit three colors (R, G, B) are provided as backlight 16. It is a so-called PC. The backlight was lit in the order of R, G, and B, and each lighting time was about 5.6 ms.
  • the control circuit 25 supplies a signal to the scan electrode drive circuit 22 and the signal electrode drive circuit 23 based on the signal from the display data generation source 26, and the scan electrode drive circuit 22 and the signal electrode drive circuit 23 Supplies a signal composed of the voltages Vx and Vy to the liquid crystal display 21 based on the given signals.
  • a reset period (R s) is provided when light emission stops while the color of the light emitted by the light source is switched.
  • the voltage applied to each pixel during this reset period is set to approximately 0 V, and the antiferroelectric liquid crystal of each pixel is simultaneously reset to the antiferroelectric state. Note that the voltage applied during the reset period (R s) does not necessarily need to be 0 V, but may be any value below the threshold.
  • FIG. 11 shows a voltage drive waveform of another embodiment using an antiferroelectric liquid crystal.
  • (BL) indicates the color of the light emitted by the backlight (light source) and the light emission period.
  • C 1) is the composite voltage waveform applied to the pixels on the first row of scan electrodes
  • C 2) is the composite voltage waveform applied to the pixels on the second row of scan electrodes
  • C 3) Represents the composite voltage waveform applied to the pixels on the scan electrodes in the third row.
  • Dl), (d2), and (d3) represent the light transmittance of each pixel on the scanning electrodes in the first to third rows. Respectively.
  • the reset period (R s) is provided in the first period in which a certain color starts emitting light (in FIG. 11, R, R s is provided in the first period when G starts emitting light). Then, the voltage applied to each pixel during this reset period is set to approximately 0 V, and the antiferroelectric liquid crystal of each pixel is simultaneously reset to the antiferroelectric state. After the reset period (R s), a selection period (S e) and a non-selection period (NS e) are provided successively. Since all pixels are reset at the same time in this manner, the number of resets can be minimized, and flicker can be suppressed.
  • the reset period is provided at the beginning of the period in which a certain color emits light
  • the selection period and the non-selection period can be set continuously during the period in which the backlight emits light. Therefore, it is possible to increase the backlight emission time while the necessary display is being written, and to obtain a bright screen and good display characteristics.
  • the reset period (R s) is provided in the last period in which the light source of a certain color stops emitting light (in FIG. 12, B , Rs is provided in the last period when R stops emitting light). Then, the voltage applied to each pixel during this reset period is set to approximately 0 V, and the anti-ferroelectric liquid crystal of each pixel is reset. Simultaneously reset to ferroelectric state. Then, a selection period (S e) and a non-selection period (NS e) are provided successively before the reset period (R e). Since all pixels are reset at the same time, the number of resets can be minimized, and flicker can be suppressed.
  • the reset period is provided at the end of the period in which a certain color emits light
  • the selection period and the non-selection period can be set continuously during the period in which the backlight emits light. Therefore, the emission time of the backlight can be increased while the necessary display is written, and the screen can be bright and good display characteristics can be obtained.
  • FIG. 13 shows a voltage driving waveform of the present invention using a ferroelectric liquid crystal.
  • (BL) indicates the color that the backlight (light source) emits and its emission period.
  • (C 1) is the composite voltage waveform applied to the pixels on the first row of scan electrodes
  • (C 2) is the composite voltage waveform applied to the pixels on the second row of scan electrodes
  • (C 3 ) Respectively indicate the composite voltage waveforms applied to the pixels on the scanning electrodes in the third row.
  • D 1), (d 2), and (d 3) represent the light transmittance of each pixel on the scanning electrodes in the first to third rows, respectively.
  • FIG. 14 shows a voltage driving waveform of another embodiment using a ferroelectric liquid crystal.
  • B L represents the color of the light emitted by the backlight (light source) and the light emission period.
  • C 1) is the composite voltage waveform applied to the pixels on the first row of scan electrodes
  • C 2) is the composite voltage waveform applied to the pixels on the second row of scan electrodes
  • C 3 Respectively indicate the composite voltage waveforms applied to the pixels on the scanning electrodes in the third row.
  • D l), (d 2), and (d 3) represent the light transmittance of each pixel on the scanning electrodes in the first to third rows, respectively.
  • FIG. 15 shows a voltage driving waveform of another embodiment using a ferroelectric liquid crystal.
  • (BL) is the color that the backlight (light source) emits and its emission 59 Indicates the period.
  • C 1) is the composite voltage waveform applied to the pixels on the first row of scan electrodes
  • C 2) is the composite voltage waveform applied to the pixels on the second row of scan electrodes
  • C 3 Respectively indicate the composite voltage waveforms applied to the pixels on the scanning electrodes in the third row.
  • Dl), (d 2), and (d 3) respectively represent the light transmittance of each pixel on the scanning electrodes in the first to third rows.
  • the reset period (R s) is set to the last period in which the light source of a certain color stops emitting light.
  • a pulse having a peak value of ⁇ 20 V or more is applied to each pixel to reset the ferroelectric liquid crystal of each pixel to the first stable state (black display state).
  • a selection period (S e) and a non-selection period (NS e) are provided successively before the reset period (R e). Since all the pixels are reset at the same time, the number of resets can be minimized, and flicker can be suppressed.
  • the reset period is provided at the end of the period in which a certain color emits light
  • the selection period and the non-selection period can be set continuously during the period in which the backlight emits light. Therefore, the emission time of the backlight while the necessary display is being written can be made longer, and the screen can be made bright and good display characteristics can be obtained.
  • Example 1 the antiferroelectric liquid crystal was reset to the antiferroelectric state during the reset period. However, good display characteristics were obtained even when resetting to the first or second ferroelectric state. Similarly, in Examples 4, 5, and 6, the ferroelectric liquid crystal was reset to the first stable state. Good results were obtained even when the force was reset to the second stable state.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Liquid Crystal Display Device Control (AREA)
  • Liquid Crystal (AREA)

Abstract

L'invention concerne un écran à cristaux liquides qui comprend des éléments anti-ferroélectriques d'écran à cristaux liquides ou des éléments ferroélectriques d'écran à cristaux liquides et une source lumineuse qui peut émettre en continu de la lumière de différentes couleurs, ladite source lumineuse s'éteignant pendant un laps de temps arbitraire lorsqu'une couleur change. Une période de remise à zéro est incluse dans ce laps de temps; pendant cette période, les cristaux liquides anti-ferroélectriques ou ferroélectriques sont remis dans un état prédéterminé. Cette période peut commencer au début de la période pendant laquelle la lumière d'une couleur donnée est émise ou à la fin de cette période.
PCT/JP1998/003859 1998-08-28 1998-08-28 Ecran a cristaux liquides et procede de pilotage dudit ecran WO2000013057A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP98940621A EP1028347A4 (fr) 1998-08-28 1998-08-28 Ecran a cristaux liquides et procede de pilotage dudit ecran
PCT/JP1998/003859 WO2000013057A1 (fr) 1998-08-28 1998-08-28 Ecran a cristaux liquides et procede de pilotage dudit ecran

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP1998/003859 WO2000013057A1 (fr) 1998-08-28 1998-08-28 Ecran a cristaux liquides et procede de pilotage dudit ecran

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EP1721306A1 (fr) * 2004-02-24 2006-11-15 Koninklijke Philips Electronics N.V. Dispositif d'affichage a electrophorese
US10845025B2 (en) 2016-09-29 2020-11-24 Lumileds Llc Lighting assembly with diffusor

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EP1028347A4 (fr) 2005-08-31

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