WO2010095686A1 - Procede d'entraînement d'afficheur a matrice par point utilisant des cristaux liquides nematiques bistables - Google Patents

Procede d'entraînement d'afficheur a matrice par point utilisant des cristaux liquides nematiques bistables Download PDF

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Publication number
WO2010095686A1
WO2010095686A1 PCT/JP2010/052457 JP2010052457W WO2010095686A1 WO 2010095686 A1 WO2010095686 A1 WO 2010095686A1 JP 2010052457 W JP2010052457 W JP 2010052457W WO 2010095686 A1 WO2010095686 A1 WO 2010095686A1
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Prior art keywords
liquid crystal
segment
common
voltage
nematic liquid
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PCT/JP2010/052457
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English (en)
Japanese (ja)
Inventor
真一 野川
雅文 星野
ジャン－デニス、ラフィット
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セイコーインスツル株式会社
ネモプティック
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Publication of WO2010095686A1 publication Critical patent/WO2010095686A1/fr

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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
    • G09G3/3622—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
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/04—Structural and physical details of display devices
    • G09G2300/0469—Details of the physics of pixel operation
    • G09G2300/0478—Details of the physics of pixel operation related to liquid crystal pixels
    • G09G2300/0482—Use of memory effects in nematic 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
    • G09G2310/06—Details of flat display driving waveforms

Definitions

  • the present invention relates to an electrical drive signal and a drive device for controlling the display of a liquid crystal display.
  • a bistable liquid crystal display has two kinds of stable states in a state where an electric signal is cut off, and the two kinds of stable states can be switched by applying an appropriate electric signal.
  • an image can be displayed in combination with a polarizing element, and the image can be changed by adding a specific electric signal. Since the display image is in a stable state even when the electric signal is turned off, it becomes a stored image and is useful for many applications. Since no power is required to maintain the display, it is effective in reducing the power consumption of the portable device.
  • Such a bistable liquid crystal panel having two kinds of stable states has been proposed as a screen called BiNem (registered trademark).
  • BiNem registered trademark
  • Patent Document 1 a method for adding an electric signal when changing a stored display is also disclosed. It is disclosed.
  • the driving voltage amplitude to be switched is large (for example, about 40 volts) at a low temperature, and conversely, the driving voltage amplitude is small (for example, 10 volts or less) at a high temperature.
  • a bistable liquid crystal panel has a larger equivalent load capacity than a normal monostable STN liquid crystal panel, so the charge / discharge charge amount is large, and the drive device requires a high current supply capability.
  • the segment signal output transistor is required to have a low ON resistance even when the drive voltage amplitude is small, such as at high temperatures. For this reason, the driving device needs to have a high driving capability and quickly charge and discharge charges between the common and the segment.
  • the bistable liquid crystal panel displays the switching voltage change on the negative side of the terminal voltage.
  • the characteristics differ between the case of control and the case of control on the positive electrode side, and a difference in drive voltage necessary for switching, a certainty of switching, that is, a difference in display image quality, and the like occur.
  • control on the negative electrode side enables efficient drive control with a small voltage amplitude, and the display quality is good, but in the drive device, the majority of the charge transfer during switching occurs at a high potential, so panel consumption The current increases.
  • control on the positive electrode side in the driving device, the majority of charge transfer during switching occurs at a low potential, so that the current consumption of the panel can be reduced.
  • the present invention provides an optimum driving means for the characteristics of such a bistable liquid crystal panel.
  • a signal for selecting two stable alignment states is selectively applied to the nematic liquid crystal from the segment drive unit connected to the segment electrode, and the common electrode and the segment
  • a dot matrix display using a bistable nematic liquid crystal that displays an image by a common-segment voltage, which is the electric field between the electrodes, the output of all common electrodes and all segment electrodes when scanning each common electrode is the same potential
  • a dot matrix display using a bistable nematic liquid crystal having a mode in which all common electrodes and all segment electrodes output the same potential to GND in a drive mode whose potential is not GND Driving method and driving means.
  • the dot display when the voltage between the terminals of the common electrode and the segment electrode holding the dot pixel is VCOM-VSEG, the dot display is in the first orientation state or the second orientation.
  • a driving method and driving means when the voltage between the terminals of the common electrode and the segment electrode holding the dot pixel is VCOM-VSEG, the dot display is in the first orientation state or the second orientation.
  • the output potential of each terminal of the common and the segment holding the dot pixel is avoided with a small amplitude while avoiding the central potential of the maximum amplitude that can be output for both the common and the segment.
  • a driving method and a driving means including a driving mode for shifting and driving VCOM-VSEG which is a voltage between both terminals with a smaller amplitude.
  • the positive side drive mode for controlling the voltage change that determines whether the dot display is white or black on the positive side of the terminal voltage.
  • a negative side drive mode that is controlled on the negative side and by selecting either of them, the negative side drive mode can be selected at low temperatures where a large drive voltage amplitude is required. Efficient drive control is performed with a small voltage amplitude, and a positive-side drive mode that is controlled on the positive side is selected except when the temperature is low to achieve driving with lower current consumption.
  • the common segment is driven and shifted with the maximum amplitude that can be output, and the voltage between both terminals: VCOM-VSEG is driven with a larger amplitude, while high temperature
  • the ON resistance of the drive transistor generally increases, so the common potential of each terminal of the common and segment is set to the center potential of the maximum amplitude that can be output for both the common and segment.
  • the negative side drive mode is selected at low temperatures where a large drive voltage amplitude is required, and drive control with higher voltage efficiency is performed, and the positive side drive mode is selected at times other than low temperatures, resulting in lower current consumption. Realization of driving.
  • the output amplitude of the segment decreases and the ON resistance of the output transistor generally increases.
  • a high temperature can be obtained. It is possible to minimize an increase in the ON resistance of the driving transistor when driving with a smaller amplitude.
  • FIG. 6 is a diagram illustrating an example of a waveform of a specific mode (Mode-D) for driving a bistable liquid crystal panel. It is a figure which shows the example of the waveform of the specific mode (Mode-H) which drives a bistable liquid crystal panel.
  • the driving method and driving device of the bistable liquid crystal display panel of the present invention can be implemented without changing the hardware of the driving device of the bistable liquid crystal display panel and by partially changing the conventional driving method. is there.
  • bistable liquid crystal display panel Before describing the embodiment of the present invention, the structure of the bistable liquid crystal display panel will be described.
  • FIG. 1 is a general functional block diagram for controlling the display of the bistable liquid crystal display panel 10.
  • the bistable liquid crystal display panel 10 generates a common drive unit 11 that drives a horizontal common line, a segment drive unit 12 that drives a vertical segment line, and drive potentials (V0, V12, V34, V5, and VCX). It is driven by a drive device comprising a power supply circuit 13, a common drive unit 11, a segment drive unit 12, and a control unit 14 that controls the power supply circuit 13.
  • the signal and role for the control unit 14 to control the common drive unit 11 and the segment drive unit 12 are the same as those of a normal STN drive driver circuit.
  • FIG. 2 is a diagram for explaining switching which is switching of the state of the bistable nematic liquid crystal.
  • a pair of substrates 1 arranged substantially opposite to each other, and an electrode 2 and an alignment film 3 are arranged in layers on a substrate on the opposite surface side of the substrate 1, and nematic liquid crystal molecules 4 are sandwiched by the substrate 1. ing.
  • the molecules 4 of the nematic liquid crystal are aligned in a predetermined direction by fine grooves carved in the alignment film 3.
  • a polarizing plate 5 is provided outside the substrate 1 on the upper surface side of the drawing.
  • a state is shown in which a specific signal is applied to the common electrode and the segment electrode of the bistable liquid crystal display panel 10 to switch the twist direction of the nematic liquid crystal molecules between two states, a twist state and a uniform state.
  • One of the write signals to be applied to the pair of electrodes 2 arranged opposite to each other in parallel is the selection COM signal shown in FIGS. 2 (a) and 2 (d), and the other is shown in FIG. 2 (b).
  • SEG signals for twist or uniform SEG signals shown in FIG.
  • the voltage between the common terminal and the segment terminal applied to the liquid crystal is of two types: a twist COM-SEG signal shown in FIG. 2C and a uniform COM-SEG signal shown in FIG.
  • the bistable liquid crystal display panel 10 When receiving the twist COM-SEG signal, the bistable liquid crystal display panel 10 can display white by the orientation of the polarizing plate 5, and can receive black by receiving the uniform COM-SEG signal. Moreover, white display and black display can be reversed by changing the state of the polarizing plate 5.
  • the common electrode and the segment electrode are substantially synonymous with the common terminal and the segment terminal, respectively.
  • the voltage waveform of the selection COM signal applied to the common terminal is such that the first time interval a of the selection period T is level 0, the time intervals b and c are negative levels ⁇ V, and the following time
  • the intervals d and e are waveforms having a positive level + V, the following time interval f is a positive level + V ⁇ v, and the remaining time interval g is a level 0 waveform.
  • the voltage waveform of the twisted SEG signal applied to the segment terminals is level 0 for the first time interval a to e of the selection period T, and negative level ⁇ v for the subsequent time interval f.
  • the remaining time interval g is a waveform at level 0.
  • the waveform of the twist COM-SEG signal which is the voltage difference between the common terminal and the segment terminal, changes with time. It becomes. That is, as shown in FIG. 2 (c), the waveform of the twisting COM-SEG signal is such that the first time interval a of the selection period T is level 0, the subsequent time intervals b and c are negative level -V, and the subsequent time.
  • the interval d to f is a waveform having a positive level + V, and the remaining time interval g is level 0.
  • the waveform of the twisting COM-SEG signal causes a voltage transition between the negative level ⁇ V volts and the positive level + V.
  • the twisted COM-SEG signal having such a waveform is applied to the nematic liquid crystal by first destroying the stable state of the alignment of the nematic liquid crystal molecules with a negative level ⁇ V voltage and a positive level + V voltage.
  • the nematic liquid crystal molecules 4 are lifted in the vertical direction (see the schematic diagram in FIG. 2 (g)), and then opened to a level 0 voltage to lay the nematic liquid crystal molecules 4 in the alignment direction (see FIG. 2). (Refer to the schematic diagram of (h)).
  • the intersection pixel of the bistable liquid crystal display panel 10 to which the twisting COM-SEG signal having the waveform shown in FIG. 2C is applied displays white in this example.
  • FIG. 2D showing the voltage waveform of the selection COM signal applied to the common terminal is the same as the waveform of FIG.
  • the voltage waveform of the uniform SEG signal is such that the first time interval a to c of the selection period T is level 0, the subsequent time interval d is a negative level ⁇ v, and the remaining time interval.
  • e to g are waveforms having a level 0.
  • the uniform COM-SEG signal which is the voltage difference between the common terminal and the segment terminal, has a waveform that changes with time. . That is, as shown in FIG. 2 (f), the waveform of the uniform COM-SEG signal is such that the first time interval a of the selection period T is level 0, the subsequent time intervals b and c are negative level -V, and the subsequent time.
  • the interval d is a positive level + (V + v)
  • the following time interval e is a positive level + V
  • the following time interval f is a positive level + V ⁇ v
  • the remaining time interval g is a level 0 waveform.
  • the uniform COM-SEG signal makes a voltage transition between ⁇ V and + (V + v).
  • FIG. 3 shows a general electrode configuration of the bistable liquid crystal display panel 10.
  • Each intersection of the common terminal arranged in the horizontal direction and the segment terminal arranged in the vertical direction is a pixel that determines display black and white, and the display is determined by applying a specific common waveform and a specific segment waveform.
  • FIG. 3 a waveform that sets the intersection pixel of the m-th column and the n-th row to a uniform state, the intersection pixel of the m-th column and the (n + 1) -th row to a twisted state, and the intersection pixel of the m-th column and the (n + 2) -th row to a uniform state.
  • An example of this is shown in FIG. 3
  • FIG. 4 shows an example of voltage waveforms applied to the common terminal and the segment terminal of the bistable liquid crystal display panel 10.
  • 4A shows a voltage waveform applied to the n-th row common terminal COM [n] arranged in the horizontal direction in the bistable liquid crystal display panel 10 shown in FIG.
  • FIG. 4B shows the voltage waveform applied to the common terminal COM [n + 1] in the (n + 1) th row
  • FIG. 4C shows the voltage waveform applied to the common terminal COM [n + 2] in the (n + 2) th row.
  • FIG. 4D shows a voltage waveform of the segment terminal SEG [m] in the m-th column arranged in the vertical direction in the bistable liquid crystal display panel 10 shown in FIG.
  • the voltage waveform of the selection COM signal 31 applied to the common terminal is as shown in the portion surrounded by the broken-line circle in FIGS. 4A to 4C, and the first time interval a of the selection period T is level 0.
  • the following time interval b is a positive level + V2
  • the following time intervals c and d are level 0
  • the following time interval e is + VCX
  • the remaining time interval f is level 0.
  • the voltage waveform of the non-selection COM signal 32 applied to the common terminal is as follows.
  • the first time intervals a and b of the selection period T are level 0 and the subsequent time interval c.
  • e is a waveform with a positive level + V2, and the remaining time interval f is level 0.
  • the voltage waveform of the signal applied to the common terminal is greatly different between FIG. 2 and FIG.
  • the voltage waveform of the selection COM signal shown in (a) and (d) of FIG. 2 is a voltage waveform that changes greatly between positive and negative, whereas the voltage waveform of the selection COM signal 31 shown in FIG.
  • the waveform changes greatly only in FIG.
  • the non-selection COM signal 32 shown in FIG. 4 also has a waveform that changes greatly only on the positive side.
  • the selection COM signal 31 is applied to the n-th common terminal COM [n] in the scan time interval t1, and the non-selection COM signal 32 is applied in the scan time intervals t2 and t3.
  • the non-selection COM signal 32 is applied to the subsequent common terminal COM [n + 1] in the (n + 1) th row, and the selection COM signal 31 is supplied in the scan time interval t2. Further, the non-selection COM signal 32 is applied in the scan time interval t3.
  • non-selection COM signal 32 is applied to the subsequent common terminal COM [n + 2] in the (n + 2) th row in the scan time intervals t1 and t2, as shown in FIG. 4C, and in the scan time interval t3. Each signal 31 is applied.
  • the segment voltage applied to the segment terminals that is, the voltage waveforms SEG [m] of the uniform SEG signal 34 and the twist SEG signal 35 are as shown in FIG.
  • the uniform SEG signal 34 is applied in the scan time interval t1
  • the twist SEG signal 35 is applied in the scan time interval t2
  • the uniform SEG signal 34 is applied in the scan time interval t3.
  • the voltage waveform of the uniform SEG signal 34 shows that the first time intervals a and b of the selection period T are level 0, the subsequent time intervals c and d are positive level + V2, the subsequent time interval e is positive level + V1, and the rest The time interval f is a waveform at level 0.
  • the voltage waveform of the twist SEG signal 35 is such that the first time intervals a and b of the selection period T are level 0, the subsequent time interval c is positive level + V1, the subsequent time intervals d and e are positive level + V2, and The remaining time interval f is a waveform having level 0.
  • the selection COM signal 31 or the non-selection COM signal 32 is applied to the common terminal, and the uniform SEG signal 34 and the twist SEG signal 35 are applied to the segment terminal, the common signal between the common terminal and the segment terminal.
  • the voltage between segments, that is, the uniform COM-SEG signal 36 and the twist COM-SEG signal 37 are as shown in FIGS.
  • the first time intervals a and b are level 0, the subsequent time interval c is negative level ⁇ V5, and the remaining time intervals d to f are level 0. Applied.
  • the parasitic signal 39 by the uniform SEG signal in which the first time interval a to d is level 0, the subsequent time interval e is negative level ⁇ V5, and the remaining time interval f is level 0 is Applied.
  • the uniform COM-SEG signal 36 and the parasitic signals 38 and 39 are applied to the intersection pixel of the common terminal in the n-th row and the segment terminal in the m-th column at the times t1, t2, and t3. Since the voltage amplitude is small, it does not affect the switching of the intersection pixel. Therefore, the intersection pixel is switched to the uniform state by the uniform COM-SEG signal 36.
  • an intersection SEG signal between the common terminal COM [n + 1] in the (n + 1) -th row and the segment terminal SEG [m] in the m-th column has a uniform SEG signal in the time interval t1, as shown in FIG.
  • the parasitic signal 39 is applied to the twist COM-SEG signal 37 in the time interval t2, and the parasitic signal 39 is applied to the uniform SEG signal in the time interval t3.
  • the twisted COM-SEG signal 37 has an initial time interval a of level 0, a subsequent time interval b of a positive level + V2, a subsequent time interval c of a negative level ⁇ V1, and a subsequent time interval d of a negative level ⁇ V2.
  • the subsequent time interval e is a negative level ⁇ V4, and the remaining time interval f is a voltage having a waveform of level 0.
  • the parasitic signal 39 does not affect the switching of the intersection pixel because the voltage amplitude is small. Therefore, the intersection pixel is switched to the twist state by the twist COM-SEG signal 37.
  • intersection pixel of the (n + 2) -th row common terminal COM [n + 2] and the m-th column segment terminal SEG [m] is subjected to the uniform SEG signal in the time interval t1, as shown in FIG.
  • the parasitic signal 39 is applied with the parasitic signal 38 by the twist SEG signal in the scan time interval t2, and the uniform COM-SEG signal 36 is applied in the scan time interval t3.
  • the uniform COM-SEG signal 36 indicates that the first time interval a of the selection period T is level 0, the subsequent time interval b is positive level + V2, the subsequent time intervals c to d are negative level ⁇ V2, and the subsequent time interval e is The negative level ⁇ V3, and the remaining time interval f is a voltage having a waveform of level 0.
  • the parasitic signals 38 and 39 do not affect the switching of the intersection pixel because the voltage amplitude is small. Therefore, the intersection pixel is switched to the uniform state by the uniform COM-SEG signal 36.
  • FIG. 6 shows an example of two types of voltage waveforms applied to the common terminal, two types of voltage waveforms applied to the segment terminals, and four types of COM-SEG waveforms generated by a combination thereof.
  • the time interval indicated by T is a unit of one output waveform.
  • four kinds of voltages applied to the intersection pixel of the common terminal and the segment terminal, uniform COM-SEG signal 65, twist COM-SEG signal 66, parasitic signal 67 by uniform SEG signal, and parasitic by twist SEG signal Signal 68 is shown.
  • the voltage waveform shown in FIG. 6 differs from that shown in FIG. 4 in the waveform applied to the segment terminals.
  • the Mode-G shown in FIG. 6 shows a voltage change (a broken line surrounded by a circle) that determines whether the dot display is white or black when the voltage between the terminals of the common and the segment, for example, the COM-SEG signal 65 for uniform is viewed.
  • a voltage change (a broken line surrounded by a circle) that determines whether the dot display is white or black when the voltage between the terminals of the common and the segment, for example, the COM-SEG signal 65 for uniform is viewed.
  • the parasitic signal when the common is not selected is generated at a high potential (V0, V12) of the segment waveform. That is, since charge and discharge of charges are performed on the pixel electrodes between the common and segment from a high potential (V0, V12), it is necessary to inject charges from a high voltage power source, and current consumption as a driving device increases.
  • the numbers “1” and “0” shown in FIG. 6D are control signals for the waveform of the common voltage applied to the common terminal and the waveform of the segment voltage applied to the segment terminal.
  • the waveform of the common voltage is controlled by four signals of CCX, C-Data, FR, and DispOffx. It is controlled by three signals of the segment voltage waveform S-Data, FR, and DispOffx.
  • Table 1 below shows the segment drive driver (SEG-Drv.) For a segment drive device that uses a driver (not the SA drive method) for driving a typical STN liquid crystal that is already commercially available. It is a truth table of an input / output table. Since the output voltage is controlled by three control signals, the correspondence between the segment control signal and the segment voltage waveform as shown in FIG.
  • the control signal for outputting the potential is CCX.
  • Table 2 shown below is a truth table of the input / output table of the common drive driver (COM-Drv.). In Table 2, if the common output is controlled as shown in the column of driving mode G (Mode-G), four common control signals (CCX, C-Data, FR, DispOffx) shown in FIG. And the correspondence of the common voltage waveform as shown in FIG.
  • the bistable liquid crystal display panel when a COM signal for selection is applied to one common terminal arranged in the horizontal direction, whether the signal of each segment terminal intersecting in the vertical direction is a signal for twisting or not.
  • the display of one pixel in the horizontal direction is determined depending on whether it is a signal.
  • Applying (scanning) selection COM signals to all common terminals while sequentially shifting the selection COM signals one by one, and applying the signals of all segment terminals each time determines the display of the entire screen.
  • a non-selection COM signal is applied to the majority of other common terminals, and a parasitic signal is applied to the intersecting segment terminals.
  • the parasitic signal greatly contributes to the charge / discharge charge amount for driving the liquid crystal panel, and affects the current consumption.
  • FIG. 7A shows a common drive waveform of Mode-E, the left two waveforms are the selection COM signals and the right two waveforms are the non-selection COM signals.
  • FIG. 7B shows a uniform SEG signal 73 and a twist SEG signal 74. Looking at the voltage between the terminals of the Mode-E common and the segment, for example, the uniform COM-SEG signal 75, first the negative side drive is followed by the positive side drive, and whether the positive side drive is twisted or uniform? A voltage change (a broken line part surrounded by a circle) is given. Driving to both sides of the negative electrode and the positive electrode is a general consideration for preventing and balancing DC bias to the liquid crystal. The same applies to the twisted COM-SEG signal 76.
  • the positive side drive mode means that the voltage change (the broken line part circled) that determines whether the pixel display is twist or uniform is controlled on the positive side.
  • a parasitic signal generated when the common is not selected, for example, a parasitic signal 77 by the uniform SEG signal is generated at a low potential (V34, V5) of the segment waveform. That is, since charge and discharge are performed on the pixel electrode between the common and the segment from a low potential (V34, V5), it is not necessary to use a high voltage power supply, and current consumption as a driving device can be suppressed small.
  • the parasitic signal 78 by the twisted SEG signal since charge and discharge are performed on the pixel electrode between the common and the segment from a low potential (V34, V5), it is not necessary to use a high voltage power supply, and current consumption as a driving device can be suppressed small.
  • the parasitic signal 78 by the twisted SEG signal since charge and discharge are performed on the pixel electrode between the common and the segment from a
  • the Mode-F shown in FIG. 8 is also the positive electrode side drive mode like the Mode-E.
  • a uniform SEG signal 83 and a twist SEG signal 84 are shown.
  • Signal 88 is shown.
  • the parasitic signal generated when the common is not selected is generated at a low potential (V34, V5) of the segment waveform.
  • the waveform of Mode-D shown in FIG. 9 is the negative side drive mode, similar to Mode-G of FIG.
  • the waveform of the selection COM signal 111 will be described.
  • the first time interval a is positive level + V34
  • the subsequent time interval b is positive level + V12
  • the subsequent time intervals c and d are positive level + V34
  • the subsequent time interval e is positive.
  • Level + VCX and the last time interval f is positive level + V34.
  • the first time intervals a and b are positive level + V34
  • the subsequent time intervals c to e are positive level + V12
  • the last time interval f is positive level + V34.
  • the first time intervals a and b are positive level + V34
  • the following time intervals c and d are positive level + V12
  • the following time interval e is positive level + V0
  • the last time interval f is a positive level + V34.
  • the first time intervals a and b are positive level + V34
  • the following time interval c is positive level + V0
  • the following time intervals d and e are positive level + V12
  • the last time is a positive level + V34.
  • the waveform of the uniform COM-SEG signal 115 will be described.
  • the first time interval a is positive level +0
  • the following time interval b is positive level +3
  • the following time intervals c and d are negative level -3, and so on.
  • the time interval e is negative level -2
  • the last time interval f is positive level +0.
  • the first time interval a is positive level +0
  • the following time interval b is positive level +3
  • the following time interval c is negative level -4
  • the following time interval d is Negative level -3
  • the following time interval e is negative level -1
  • the last time interval f is positive level +0.
  • the waveform of the parasitic signal 117 based on the uniform SEG signal is described as follows.
  • the first time interval a to d is positive level +0
  • the subsequent time interval e is negative level ⁇ 1
  • the last time interval f is positive level +0.
  • the first time intervals a and b are positive level +0
  • the subsequent time interval c is negative level ⁇ 1
  • the last time intervals d to f are positive level +0.
  • the COM signal 111 for selection, the COM signal 112 for non-selection, the SEG signal 113 for uniform, and the SEG signal 114 for twist are shown.
  • the COM-SEG signal 115 for uniform, the COM-SEG signal 116 for twist, and the uniform A parasitic signal 117 by the SEG signal and a parasitic signal 118 by the twist SEG signal are shown.
  • the common amplitude is from V12 to V34, which is two steps smaller than the maximum amplitude from V0 to V5.
  • the segment also has a basic amplitude from V12 to V34, which is two steps less than the maximum amplitude from V0 to V5.
  • Mode-H shown in FIG. 10 is also a negative electrode side drive mode.
  • the COM signal for selection 121, the COM signal for non-selection 122, the SEG signal for uniform 123, and the SEG signal for twist 124 are shown.
  • the uniform COM-SEG signal 125, the COM-SEG signal for twist 126, and the uniform A parasitic signal 127 based on the SEG signal and a parasitic signal 128 based on the twisted SEG signal are shown.
  • the waveform of the selection COM signal 121 will be described.
  • the first time interval a is positive level + V5
  • the subsequent time interval b is positive level + V12
  • the subsequent time intervals c and d are positive level + V34
  • the subsequent time interval e is positive.
  • Level + VCX and the last time interval f is a positive level V5.
  • the first time interval a is positive level + V5
  • the following time interval b is positive level + V34
  • the following time intervals c to e are positive level + V12
  • the last time interval f becomes a positive level V5.
  • the first time interval a is positive level + V5
  • the following time interval b is positive level + V34
  • the following time intervals c and d are positive level + V12
  • e is a positive level + V0
  • the last time interval f is a positive level + V5.
  • the waveform of the twisted SEG signal 124 will be described.
  • the first time interval a is positive level + V5
  • the following time interval b is positive level + V34
  • the following time interval c is +0 V
  • the following time intervals d and e are positive level + V12.
  • the last time interval f becomes a positive level + V5.
  • First time interval a is positive level +0
  • subsequent time interval b is positive level +3
  • subsequent time intervals c and d are negative level -3, and so on.
  • the time interval e is negative level -2
  • the last time interval f is positive level +0.
  • the first time interval a is positive level +0
  • the following time interval b is positive level +3
  • the following time interval c is negative level -4
  • the following time interval d is Negative level -3
  • the following time interval e is negative level -1
  • the last time interval f is positive level +0.
  • the waveform of the parasitic signal 127 based on the uniform SEG signal is described as follows.
  • the first time interval a to d is positive level +0
  • the subsequent time interval e is negative level ⁇ 1
  • the last time interval f is positive level +0.
  • the first time intervals a and b are positive level +0
  • the subsequent time interval c is negative level ⁇ 1
  • the last time intervals d to f are positive level +0.
  • the parasitic signal generated when the common is not selected is generated at a high potential (V0, V12) of the segment waveform.
  • the ON resistance of the output transistor is most increased due to the substrate effect when the central potential (1/2 potential) of the maximum amplitude that can be output by the transistor is output. When a lower ON resistance is required, Output should be avoided.
  • both the common and segment are output at the maximum amplitude (V0-V5), one stage from the upper limit, When output with a potential (V12-V34) with one stage lower than the lower limit and a total of two stages of amplitude reduced, the COM-SEG voltage is driven with an amplitude that is four stages smaller than when the maximum amplitude (V0-V5) is output. Is done.
  • V0 and V5 when the voltage between V0 and V5 is about 10V, if both the common and segment are output with the maximum amplitude (V0-V5), the COM-SEG voltage will have an amplitude of ⁇ 10V, but the potentials of V12 and V34 will be If the common and segment are output with amplitudes of V12 and V34 by setting 2V inside from the upper and lower limits, the COM-SEG voltage has an amplitude of ⁇ 6V.
  • a small amplitude drive of ⁇ 6 V can be realized without significantly increasing the ON resistance of.
  • the COM-SEG voltage can be driven with a smaller amplitude without increasing the ON resistance of the output transistor. it can.
  • Mode-F is a small amplitude waveform of the positive side drive mode as opposed to Mode-H in FIG.
  • the end of COM and SEG is changed to V5 (GND) instead of V34, and it is possible to drive without using the output amplifier capability of V34 at the end of voltage transition. is doing.
  • Mode-E in FIG. 7 and Mode-G in FIG. 6 are both driven at the maximum amplitude, although there are differences between the positive side and negative side drive modes.
  • the output of the common and the segment changes with the maximum amplitude of V0-V5, and the voltage waveform between COM and SEG also has the maximum amplitude.
  • Mode-E or Mode-G is selected, and when driving with a smaller voltage amplitude, Mode-F or Mode-H is selected.
  • Each potential (V0, V12, VCX, V34, V5) of the drive waveform shown in FIG. 7 is optimum according to the size of the liquid crystal panel, the number of pixels, the ambient temperature, and the like, similar to the drive potential of a general-purpose STN driver.
  • Set to voltage Since a high driving voltage is required for the liquid crystal at a low temperature, the voltage between V0 and V5 is increased and the liquid crystal is driven in the negative side driving mode (Mode-G) with good voltage efficiency.
  • Mode-G negative side driving mode
  • Mode-E drive with positive side drive mode
  • reduce voltage between V0 and V5 and drive with Mode-F or Mode-H At high temperature, reduce voltage between V0 and V5 and drive with Mode-F or Mode-H.
  • the drive amplitude between COM and SEG is small, the voltage between V0 and V5 is kept as large as possible to minimize the increase in the ON resistance of the output transistor.
  • the present invention can be used for all liquid crystal displays.
  • the industrial applicability is particularly high particularly in the use of electronic shelf labels and electronic paper.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Liquid Crystal (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)

Abstract

L'invention concerne un procédé permettant d'entraîner un afficheur à matrice par point utilisant des cristaux liquides nématiques bistables. A basse température, on choisit un mode d'entraînement latéral négatif (Mode-G) pour exécuter une commande d'entraînement avec une efficacité de tension plus élevée, et à température ambiante ou à haute température, on choisit un mode d'entraînement latéral positif (Mode-E) pour exécuter un entraînement avec une consommation de courant plus faible. Lors de l'entraînement à petite amplitude à température élevée, on choisit les modes (Mode-F, Mode-H) dans lesquels les tensions de sortie de terminaux communs et de terminaux de segments changent à petite amplitude afin de minimiser une augmentation de la résistance en saturation du transistor de sortie. L'utilisation sélective des modes d'entraînement permet d'entreprendre un entraînement rationnel conformément aux caractéristiques d'un panneau à cristaux liquides nématiques bistables.
PCT/JP2010/052457 2009-02-19 2010-02-18 Procede d'entraînement d'afficheur a matrice par point utilisant des cristaux liquides nematiques bistables WO2010095686A1 (fr)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2491972A (en) * 2011-06-14 2012-12-19 Knorr Bremse Rail Systems Uk Ltd Brake information module having a bistable display to display operational data, even without power
CN102855847A (zh) * 2012-08-28 2013-01-02 无锡威峰科技有限公司 应用于epd屏的波形调试方法
CN114067761A (zh) * 2020-07-29 2022-02-18 精工爱普生株式会社 集成电路装置、液晶显示装置、电子设备以及移动体

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Publication number Priority date Publication date Assignee Title
JPH08194206A (ja) * 1995-01-13 1996-07-30 Nippondenso Co Ltd マトリクス型液晶表示装置
JPH10115822A (ja) * 1996-10-14 1998-05-06 Seiko Epson Corp 液晶表示体の駆動方法
JPH10197846A (ja) * 1997-01-10 1998-07-31 Ricoh Co Ltd 液晶パネルの駆動方法
JP2006518479A (ja) * 2003-02-20 2006-08-10 ネモプティック 改善された双安定性ネマティック液晶ディスプレイ方法およびデバイス
JP2007256608A (ja) * 2006-03-23 2007-10-04 Citizen Holdings Co Ltd メモリ性液晶パネル
WO2010021206A1 (fr) * 2008-08-19 2010-02-25 セイコーインスツル株式会社 Procédé et dispositif pour piloter un dispositif d'affichage nématique, bistable, à matrice de points

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08194206A (ja) * 1995-01-13 1996-07-30 Nippondenso Co Ltd マトリクス型液晶表示装置
JPH10115822A (ja) * 1996-10-14 1998-05-06 Seiko Epson Corp 液晶表示体の駆動方法
JPH10197846A (ja) * 1997-01-10 1998-07-31 Ricoh Co Ltd 液晶パネルの駆動方法
JP2006518479A (ja) * 2003-02-20 2006-08-10 ネモプティック 改善された双安定性ネマティック液晶ディスプレイ方法およびデバイス
JP2007256608A (ja) * 2006-03-23 2007-10-04 Citizen Holdings Co Ltd メモリ性液晶パネル
WO2010021206A1 (fr) * 2008-08-19 2010-02-25 セイコーインスツル株式会社 Procédé et dispositif pour piloter un dispositif d'affichage nématique, bistable, à matrice de points

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2491972A (en) * 2011-06-14 2012-12-19 Knorr Bremse Rail Systems Uk Ltd Brake information module having a bistable display to display operational data, even without power
GB2491972B (en) * 2011-06-14 2018-05-09 Knorr Bremse Rail Systems Uk Ltd A Brake System for a Vehicle with an Electrically Powered Brake Control Unit
CN102855847A (zh) * 2012-08-28 2013-01-02 无锡威峰科技有限公司 应用于epd屏的波形调试方法
CN102855847B (zh) * 2012-08-28 2014-09-24 无锡威峰科技有限公司 应用于epd屏的波形调试方法
CN114067761A (zh) * 2020-07-29 2022-02-18 精工爱普生株式会社 集成电路装置、液晶显示装置、电子设备以及移动体

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