JP2014013280A - Display device and driving method for display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving method for a display panel, which uses ferro-electric liquid crystal molecules, the method being able to accurately display black, and to provide the other.SOLUTION: A driving method for a liquid crystal device 100, according to the invention, is provided for displaying an image on a display panel 110 provided in front of an illuminating device 140. In the method, a drive voltage for driving each liquid crystal molecule LC is applied to the liquid crystal molecule LC based on pixel data. Especially in order to control the transmission light intensity of light, emitted from the illuminating device 140, in each pixel, the tilt of the liquid crystal molecule LC in a first direction, which moves in the direction of a reference axis 51 based on a first polarization axis 52, and the tilt of a liquid crystal molecule LC in a second direction, which moves in a direction away from the reference axis 51, are controlled according to the voltage level and polarity of a drive voltage (a voltage held in a capacitor C) applied to the liquid crystal molecule LC.

Description

  The present invention relates to a display device and a display panel driving method.

  Conventionally, liquid crystal display elements have been widely used as lightweight and thin display elements. In particular, compared with a liquid crystal display device using nematic liquid crystal such as TN (Twisted Nematic), STN (Super Twisted Nematic) multiplex drive, or active matrix drive using a thin layer transistor (TFT) for TN. Therefore, research on ferroelectric liquid crystal (FLC), which has an extremely short response speed and is suitable for high-speed devices, is in progress.

  As a liquid crystal display device using such a ferroelectric liquid crystal element, in order to accurately display “black”, a predetermined number of simultaneous operations are performed on all pixel electrodes (pixels) during one frame erasing process. A device that executes application of a driving voltage by selection is known (for example, Patent Document 1).

JP 2003-5153 A

  However, in the above-mentioned patent document, regarding the execution of “black” display, the axis extending in the rubbing direction when no drive voltage is applied is not parallel and is inclined so as to be parallel to the polarization axis of one polarizing plate. No mention is made of the application of a driving voltage for a liquid crystal display device using ferroelectric liquid crystal molecules that are stabilized in a stable manner and a driving circuit thereof.

  In the above-mentioned patent document, only the reset pulse is used in order to accurately perform black display. As long as there is no mention of the above, the axis extending in the rubbing direction when no drive voltage is applied. It is impossible to improve the black display ability due to the property of the ferroelectric liquid crystal having the property of being non-parallel and being tilted and stabilized so as to be parallel to the polarization axis of one polarizing plate.

  The present invention has been made to solve the above-mentioned problems, and its purpose is to be non-parallel to the axis extending in the rubbing direction when no drive voltage is applied and parallel to the polarization axis of one polarizing plate. An object of the present invention is to provide a display panel driving method and the like that can accurately perform black display in a display panel using ferroelectric liquid crystal molecules that are inclined and stabilized.

  (1) In order to solve the above problems, a display panel driving method according to the present invention includes a first polarizing plate having a first polarization axis and a second polarization axis that is non-parallel to the first polarization axis. A pair of alignment films sandwiched between the polarizing plate and the first polarizing plate and the second polarizing plate and rubbed in a direction of a reference axis non-parallel to the first polarizing axis and the second polarizing axis; A liquid crystal layer sandwiched between alignment films, which is tilted and stabilized so as to be parallel to one polarization axis when no drive voltage is applied, and includes a liquid crystal layer enclosing liquid crystal molecules having spontaneous polarization. A display panel driving method having pixels and displaying an image on a display panel provided in front of a light source, wherein (A) a driving voltage is applied to each liquid crystal molecule based on image data input by a driving circuit (B) in each pixel of light emitted from the light source. In order to control the transmitted light intensity, the liquid crystal molecule tilts in a first direction that moves in the direction of the reference axis with respect to the first polarization axis according to the voltage level and polarity of the applied drive voltage. And (C) the voltage level of the driving voltage applied to the corresponding liquid crystal molecules during the driving of each liquid crystal molecule, controlling the inclination of the liquid crystal molecules in the second direction moving away from the reference axis. Is changed within a predetermined range of a predetermined reference potential (including “0 V”), a driving voltage for tilting the liquid crystal molecules further in the second direction from the first polarization axis is applied to the liquid crystal molecules. After being applied, the drive voltage to be applied is changed within a predetermined range of the reference potential.

  Usually, using an alignment film that is rubbed in the direction of the reference axis that is not parallel to the first polarization axis and the second polarization axis, the tilt is stable so that it is parallel to one polarization axis when no drive voltage is applied. If the liquid crystal molecules with spontaneous polarization are sealed in the liquid crystal layer, the voltage level of the drive voltage is changed within the predetermined range of the reference potential from the side with the larger tilt angle in the liquid crystal molecules of the ferroelectric liquid crystal. Even if the tilt of the liquid crystal molecules is not quickly returned to the original or substantially parallel to the first polarization axis, the light emitted from the light source is quickly blocked (including a state close to blocking). It is difficult to make each pixel display “black”. That is, when the liquid crystal molecules are tilted in the first direction moving in the direction of the reference axis with respect to the first polarization axis, the voltage level of the drive voltage is changed from the tilted position to a predetermined range of the reference potential. However, the tilt of the liquid crystal molecules does not quickly return to be parallel or substantially parallel to the first polarization axis.

  On the other hand, in the case where such liquid crystal molecules are sealed in the liquid crystal layer, the liquid crystal molecules are viewed from the side with a small tilt angle, that is, the direction of the reference axis with respect to the first polarization axis. When the voltage level of the drive voltage is changed within the predetermined range of the reference potential from the tilt position when tilted in the first direction to move to the first direction, the tilt of the liquid crystal molecules is parallel to or approximately the first polarization axis. Return quickly in parallel.

  According to the present invention, the voltage level of the driving voltage applied to the corresponding liquid crystal molecule during the driving of each liquid crystal molecule is changed within a predetermined range (including “0 V”) of a predetermined reference potential. In addition, after a driving voltage for tilting the liquid crystal molecules in the second direction from the first polarization axis is applied to the liquid crystal molecules, the driving voltage to be applied may be changed within a predetermined range of the reference potential. Therefore, the voltage level of the drive voltage applied to the liquid crystal molecules from the side where the tilt angle in the liquid crystal molecules of the ferroelectric liquid crystal is small can always be changed within the predetermined range of the reference potential.

  Therefore, the display panel driving method according to the present invention can return the tilt of the liquid crystal molecules and smoothly shift the liquid crystal molecules to a state parallel or substantially parallel to the first polarization axis. Can be displayed on the display panel.

  (2) In the display panel driving method according to the present invention, the driving voltage of the corresponding liquid crystal molecule is changed within a predetermined range (including “0 V”) of the reference potential during driving of each liquid crystal molecule. A driving voltage for further tilting the liquid crystal molecules in the second direction from the first polarization axis when the corresponding liquid crystal molecules are tilted in the first direction from the first polarization axis. Is applied to the liquid crystal molecules, and then the drive voltage to be applied is changed within a predetermined range of the reference potential.

  According to the present invention, when the corresponding liquid crystal molecules are tilted from the first polarization axis toward the first direction, the driving voltage for tilting the liquid crystal molecules further from the first polarization axis in the second direction. Is applied to the liquid crystal molecules, and then the driving voltage to be applied can be changed within the predetermined range of the reference potential, so that the liquid crystal molecules must always be applied from the side of the ferroelectric liquid crystal molecules having a small tilt angle. The voltage level of the drive voltage applied to can be changed within a predetermined range of the reference potential.

  Therefore, in the display panel driving method according to the present invention, when the driving voltage is changed within the predetermined range of the reference potential, the inclination of the liquid crystal molecules is quickly returned and the liquid crystal molecules are parallel to the first polarization axis or Since it can be smoothly shifted to a substantially parallel state, “black” can be accurately displayed on the display panel.

  (3) In the display panel driving method according to the present invention, the driving voltage applied to the corresponding liquid crystal molecules in the second direction further from the first polarization axis may be applied to the liquid crystal molecules from the first polarization axis. This is a voltage having a polarity opposite to that of the drive voltage applied when tilting toward the first direction.

  According to the present invention, the driving voltage applied to the corresponding liquid crystal molecule is a voltage having a polarity opposite to that of the driving voltage applied when the liquid crystal molecule is tilted from the first polarization axis toward the first direction. Therefore, the voltage level of the driving voltage applied to the liquid crystal molecules from the side with the smaller tilt angle in the liquid crystal molecules of the ferroelectric liquid crystal can always be changed within the predetermined range of the reference potential.

(4) In the display panel driving method according to the present invention, a driving voltage whose polarity is inverted at a predetermined cycle is applied to each liquid crystal molecule based on the input image data.
The polarity immediately before the drive voltage when changing the reference potential within a predetermined range is a voltage polarity for further tilting the liquid crystal molecules in the second direction from the first polarization axis.

  According to the present invention, the polarity immediately before the drive voltage when changing within the predetermined range of the reference potential is the voltage polarity that further tilts the liquid crystal molecules in the second direction from the first polarization axis. It is possible to change the voltage level of the driving voltage applied to the liquid crystal molecules from the side where the tilt angle is small in the liquid crystal molecules of the ferroelectric liquid crystal within a predetermined range of the reference potential.

  (5) In the display panel driving method according to the present invention, the maximum tilt angle of the liquid crystal molecules in the second direction is greater than the maximum tilt angle of the liquid crystal molecules in the first direction with respect to the reference axis. Is small.

  According to the present invention, since the voltage level of the driving voltage can be changed within a predetermined range of the reference potential from the side of the liquid crystal molecule of the ferroelectric liquid crystal where the tilt angle is small, the inclination of the liquid crystal molecule is returned to the liquid crystal molecule. Molecules can be smoothly transferred to a state parallel or substantially parallel to the first polarization axis.

  (6) In the display panel driving method according to the present invention, the liquid crystal molecules have ferroelectric properties.

  According to the present invention, even in a liquid crystal molecule having ferroelectric properties, the voltage level of the drive voltage applied to the liquid crystal molecule from the side with the small tilt angle in the liquid crystal molecule of the ferroelectric liquid crystal is always set to the reference potential. It can be changed within a predetermined range.

  (7) In the display panel drive method according to the present invention, the drive voltage applied to the liquid crystal molecules when the drive circuit generates the pixel data based on the data stored in the storage means. Changes within a predetermined range of the reference potential (including “0V”), the drive voltage applied to the liquid crystal molecules immediately before that tilts the liquid crystal molecules further in the first direction from the first polarization axis. If the previous drive voltage is a drive voltage for further tilting the liquid crystal molecules in the first direction from the first polarization axis, the previous drive voltage is The driving voltage for tilting the liquid crystal molecules in the second direction further from the first polarization axis is rewritten.

  According to the present invention, when the immediately preceding drive voltage is a drive voltage for tilting the liquid crystal molecules further in the first direction from the first polarization axis, the immediately preceding drive voltage is changed from the first polarization axis. Further, since the driving voltage for tilting the liquid crystal molecules in the second direction can be rewritten, the voltage level of the driving voltage applied to the liquid crystal molecules from the side where the tilt angle in the liquid crystal molecules of the ferroelectric liquid crystal is small is surely changed. The reference potential can be changed within a predetermined range.

  (8) In order to solve the above-described problem, a display device according to the present invention is a display device that displays an image on a display panel having a plurality of pixels provided in front of a light source, and each pixel has a first polarization. A first polarizing plate having an axis; a second polarizing plate having a second polarizing axis that is non-parallel to the first polarizing axis; and the first polarizing plate sandwiched between the first polarizing plate and the second polarizing plate. A pair of alignment films rubbed in the direction of the reference axis that is not parallel to the axis and the second polarization axis, and a liquid crystal layer sandwiched between the alignment films, and parallel to one polarization axis when no drive voltage is applied And a liquid crystal layer that encloses liquid crystal molecules that are tilted and stabilized and have spontaneous polarization, and a driving voltage that drives the liquid crystal molecules is applied to each liquid crystal molecule based on input image data A drive circuit that further comprises: In order to control the transmitted light intensity at each pixel of the light emitted from the light source, it moves in the direction of the reference axis with respect to the first polarization axis according to the voltage level and polarity of the applied drive voltage. Controlling the tilt of the liquid crystal molecules in the first direction and the tilt of the liquid crystal molecules in the second direction moving away from the reference axis, and applying them to the corresponding liquid crystal molecules while driving each liquid crystal molecule In order to further tilt the liquid crystal molecules in the second direction from the first polarization axis when the voltage level of the drive voltage is changed within a predetermined range (including “0V”) of a predetermined reference potential. After the drive voltage is applied to the liquid crystal molecules, the drive voltage is changed within a predetermined range of the reference potential.

  According to the present invention, the voltage level of the driving voltage applied to the corresponding liquid crystal molecule during the driving of each liquid crystal molecule is changed within a predetermined range (including “0 V”) of a predetermined reference potential. In addition, after a driving voltage for tilting the liquid crystal molecules in the second direction from the first polarization axis is applied to the liquid crystal molecules, the driving voltage to be applied may be changed within a predetermined range of the reference potential. Therefore, the voltage level of the drive voltage applied to the liquid crystal molecules from the side where the tilt angle in the liquid crystal molecules of the ferroelectric liquid crystal is small can always be changed within the predetermined range of the reference potential.

  Therefore, the display device according to the present invention can always change the voltage level of the driving voltage applied to the liquid crystal molecules from the side with the small tilt angle in the liquid crystal molecules of the ferroelectric liquid crystal within the predetermined range of the reference potential. Therefore, the tilt of the liquid crystal molecules can be quickly returned, the liquid crystal molecules can be smoothly shifted to a state parallel or substantially parallel to the first polarization axis, and “black” can be accurately displayed on the display panel. it can.

  In the display panel driving method and the display device according to the present invention, the voltage level of the driving voltage applied to the liquid crystal molecules from the side where the tilt angle in the liquid crystal molecules of the ferroelectric liquid crystal is small is always within the predetermined range of the reference potential. Since it can be changed, the tilt of the liquid crystal molecules can be returned, and the liquid crystal molecules can be smoothly shifted to a state parallel or substantially parallel to the first polarization axis. Therefore, the display panel driving method and the display device according to the present invention can display “black” on the display panel quickly and reliably.

It is a block diagram which shows the circuit structure in one Embodiment of the display apparatus which concerns on this invention. It is a block diagram which shows the structure of the display panel in one Embodiment, a scanning line drive circuit, and a data line drive circuit. It is a circuit diagram which shows the internal structure of each pixel of one Embodiment. FIG. 3 is a structural diagram simulating the structure of each liquid crystal element according to an embodiment. It is a schematic diagram which shows the behavior of the liquid crystal molecule of a ferroelectric liquid crystal. It is a figure which shows the relationship between the behavior of the liquid crystal molecule of one Embodiment, a 1st polarizing plate, a 2nd polarizing plate, and a pair of alignment film. It is a graph which shows the V-shaped switching characteristic which becomes asymmetric in the positive / negative drive voltage in the liquid crystal molecule of the ferroelectric liquid crystal of one Embodiment. It is a graph which shows the experimental result at the time of changing the voltage level of a drive voltage in the predetermined range of a predetermined reference electric potential in the liquid crystal molecule which has a V-shaped switching characteristic which becomes asymmetrical in positive / negative drive voltage. It is a graph which shows the experimental result for defining the range of the reference potential in the liquid crystal molecule in one embodiment. FIG. 10 is a graph showing the experimental results of FIG. 9 based on the relationship between transmitted light intensity and input voltage. It is a flowchart which shows operation | movement of each liquid crystal molecule of the ferroelectric liquid crystal based on the drive voltage of one Embodiment. It is a figure for demonstrating the production | generation method of the pixel data of one Embodiment (at the time of 1 time speed drive). It is a figure for demonstrating the production | generation method of the pixel data of one Embodiment (at the time of double speed drive).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a display panel driving method according to the present invention is compared with an active matrix driving type liquid crystal display device constituted by pixels having liquid crystal molecules using a ferroelectric liquid crystal material and a driving method thereof. And an embodiment in which a display device is applied. However, the present invention is not limited to the following embodiments within the scope including the technical idea.

[1] Display Device First, the liquid crystal display device 100 of this embodiment will be described with reference to FIGS. 1 and 2. 1 is a block diagram illustrating a circuit configuration of the display device according to the present embodiment, and FIG. 2 is a block diagram illustrating configurations of the display panel 110, the scanning line driving circuit 130, and the data line driving circuit 120 according to the present embodiment. FIG.

  As shown in FIGS. 1 and 2, the liquid crystal display device 100 according to the present embodiment includes a plurality of pixels 10 including liquid crystal elements 30, a display panel 110 that displays a predetermined image, and a plurality of data lines. A data line driving circuit 120 that controls each pixel 10 via X, a scanning line driving circuit 130 that controls each pixel 10 via a plurality of scanning lines Y, and an illumination device 140 that functions as a backlight of the display panel 110. A memory circuit 150 that temporarily stores image data to be displayed on the display panel 110, and a control circuit 170 that controls each unit.

  As shown in FIG. 2, the display panel 110 includes m columns of data lines X1 to Xm (m is an integer) extending along the column direction and n rows of scanning lines Y1 to Yn (m extending along the row direction). A plurality of (n × m) pixels 10 arranged in n rows and m columns are provided at positions corresponding to intersections with n).

  Each pixel 10 includes a liquid crystal element 30 having a liquid crystal layer 35 in which liquid crystal molecules LC made of a ferroelectric liquid crystal material are enclosed. Each pixel 10 has a structure for controlling the liquid crystal element 30 based on signals from the corresponding scanning line Y and data line X supplied to each pixel 10. The configuration of each pixel 10 of this embodiment will be described later.

  The data line driving circuit 120 has a plurality of data lines X1 to Xm as shown in FIG. 2 under the control of the control circuit 170, and pixel data is respectively transmitted to the pixels 10 via the data lines X1 to Xm. Supply. In particular, the data lines X1 to Xm are connected to the source electrode of the TFT 20 of each pixel 10. The signal supplied by the data line X is a signal corresponding to multi-value data for performing gradation display, and for example, data for supplying a plurality of voltage value signals to each pixel 10. It is a line control signal (hereinafter also referred to as “pixel data”).

  The scanning line driving circuit 130 has a plurality of scanning lines Y1 to Yn in n rows under the control of the control circuit 170, and the n scanning lines Y1 to Yn in order at a predetermined timing. It is configured to perform vertical scanning for selecting one by one. In particular, the scanning lines Y1 to Yn are connected to the gate electrode of the TFT 20 of each pixel 10. In addition, the scanning line driving circuit 130 sets the TFT 20 of each pixel 10 (pixels for one row) connected to one scanning line Y selected from the n × m pixels 10 to an ON state.

  The illuminating device 140 is an illuminating unit that irradiates the display panel 110 from the back side. For example, in the case of the field sequential method, the illuminating device 140 is configured by RGB LEDs for each pixel 10. In particular, the illuminating device 140 operates in sequence with the data line driving circuit 120 and the scanning line driving circuit 130 under the control of the control circuit 170, and sequentially turns on each color light of RGB at a predetermined timing. The light is irradiated onto the display panel 110 from the back side.

  In the case of the color filter method, the illumination device 140 is configured by a plurality of white LEDs.

  The memory circuit 150 stores image data supplied with image data to be displayed on the display panel 110 from the outside. In particular, the memory circuit 150 has a frame memory function for storing one or more frames.

  In particular, in the present embodiment, while performing polarity inversion driving, image data supplied from the outside is input as an absolute value of sequential data. Therefore, image data input for each frame is converted into a predetermined matrix. It is necessary to rewrite the data. In the present embodiment, a memory circuit 150 is provided to perform this rewriting.

  The control circuit 170 controls the above-described units such as the display panel 110 in an integrated manner. In particular, the control circuit 170 converts the image data stored in the memory circuit 150 representing the display state of the display panel 110 into matrix data representing the light emission gradation of the liquid crystal element 30 in each pixel 10.

  The matrix data includes a scanning line control signal for designating scanning lines Y1 to Yn for outputting scanning signals to select pixels 10 for one row, and a liquid crystal element 30 of a pixel group selected for each row. And a data line control signal (that is, pixel data) for setting the luminance. The scanning line Y control signal is supplied to the scanning line driving circuit 130, and the data line control signal is supplied to the data line driving circuit 120.

  Specifically, the control circuit 170, for example, inverts all pixels at the same polarity at the same time every frame (1/60 seconds) (frame inversion method), or alternates every other pixel for each frame. Then, matrix data is generated for alternating voltage driving (ie, polarity inversion driving) of each pixel 10 with pixel data by a method of inverting the positive and negative polarities (dot inversion driving method).

  In particular, in the control circuit 170, the pixel data immediately before the gradation value is switched always has a certain polarity (to be described later, for example, the liquid crystal molecules LC are inclined further in the second direction from the first polarization axis 52, for example, a negative polarity). Generate matrix data.

  In addition, the control circuit 170 repeats the selection operation of the scanning lines Y1 to Yn a plurality of times as many as the number of colors to irradiate the display panel 110, so that one frame image is formed and the data line driving circuit 120 and the scanning lines The drive circuit 130 is controlled.

[2] Pixel [2.1] Outline Configuration of Pixel Next, the outline configuration of the pixel 10 of the present embodiment will be described with reference to FIGS. FIG. 3 is a circuit diagram showing an internal configuration of each pixel 10 of the present embodiment, and FIG. 4 is a structural diagram simulating the structure of each liquid crystal element 30 of the present embodiment. 5 is a schematic diagram showing the behavior of the liquid crystal molecules LC of the ferroelectric liquid crystal, and FIG. 6 shows the behavior of the liquid crystal molecules LC of the present embodiment, the first polarizing plate 32, the second polarizing plate 42, and a pair. It is a figure which shows the relationship with alignment film (33,43). Further, FIG. 7 is a graph showing V-shaped switching characteristics that are asymmetrical in positive and negative drive voltages (that is, voltages applied by pixel data) in the liquid crystal molecules LC of the ferroelectric liquid crystal of the present embodiment.

  As shown in FIG. 3, each pixel 10 of the present embodiment includes the liquid crystal element 30 described above, a capacitor C that holds a predetermined amount of charge, and a TFT 20 for writing pixel data to the capacitor C.

  Each liquid crystal element 30 is formed between a drain electrode of the TFT 20 and a common electrode (not shown), and is formed of a ferroelectric liquid crystal material having spontaneous polarization and having memory properties based on the spontaneous polarization. . Each liquid crystal element 30 is driven based on the voltage held in the capacitor C.

  Specifically, as shown in FIG. 4, each liquid crystal element 30 includes a first polarizing plate 32 having a first polarization axis 52 (that is, a first polarizing axis 52 formed on a first base 31 disposed on the lighting device 140 side). , A polarizer on which light emitted from the illumination device 140 is directly incident) and a first polarization axis 52 that is not parallel to the first polarization axis 52 formed on the second base material 41 disposed on the viewing side viewed by the user. The second polarizing plate 42 (that is, the analyzer) having the two polarizing axes 53 is sandwiched between the first polarizing plate 32 and the second polarizing plate 42, and is not in contact with the first polarizing axis 52 and the second polarizing axis 53. A pair of alignment films (33, 43) that have been rubbed in the direction of the parallel reference axis 51, and a liquid crystal layer 35 sandwiched between the alignment films (33, 43), and one polarized light when no drive voltage is applied A liquid crystal molecule LC that stabilizes by tilting parallel to the axis and has spontaneous polarization. Comprising a liquid crystal layer 35 to enter, a.

  As shown in FIG. 5, the liquid crystal molecules LC of the ferroelectric liquid crystal sealed in the liquid crystal layer 35 are inclined from the layer normal z parallel to the alignment films (33, 43), and are perpendicular to the layer normal z. It has a characteristic of rotating along a ridge line of a cone having a simple bottom surface. In such a cone, the tilt angle of the liquid crystal molecule LC with respect to the layer normal z is referred to as a tilt angle (θ).

  The liquid crystal molecules LC have V-shaped switching (hereinafter referred to as “V-shaped switching”) characteristics that rotate when either positive or negative voltage is applied, and the applied drive voltage (that is, the capacitor C is applied to the capacitor C). Depending on the polarity of the voltage written by the pixel data) and its level, it operates on the cone between two states inclined by a tilt angle ± θ with respect to the layer normal z.

  In particular, as shown in FIG. 6, the liquid crystal molecule LC of the present embodiment has an alignment film (33) in a planar view direction (a direction from the top surface to the back surface) from the first polarizing plate 32 when no drive voltage is applied. 43) has a predetermined angle of inclination from the reference axis 51 extending in the rubbing direction R, and is parallel to the first polarization axis 52 (hereinafter also simply referred to as “polarization axis”) of the first polarizing plate 32. It has the characteristic which becomes a stable state at the position. The first polarizing axis 52 of the first polarizing plate 32 and the second polarizing axis 53 of the second polarizing plate 42 are set to intersect at right angles.

  In general, the inclination of the liquid crystal molecules LC operates in a range of 90 degrees, −45 degrees ≦ θ ≦ 45 degrees, with respect to the reference axis 51 in the rubbing direction R in the plan view direction from the first polarizing plate 32. Therefore, the liquid crystal molecule LC of the present embodiment has a stable state when no driving yard pressure is applied as described above, and therefore has a characteristic that the tilt angle is asymmetric at positive and negative driving voltages. ing. That is, the liquid crystal molecules LC of the present embodiment have a property that transmitted light intensity is different even when positive and negative drive voltages of the same voltage level are applied. For example, as shown in FIG. 7, the liquid crystal molecule LC of the present embodiment has a V-shaped switching characteristic that is asymmetric with respect to positive and negative drive voltages.

  For example, in the case illustrated in FIG. 6, when a positive voltage is applied, the liquid crystal molecules LC are aligned in the direction of the reference axis 51 (hereinafter, “first direction”) with respect to the first polarization axis 52. When the negative voltage is applied, the liquid crystal molecules LC are separated from the reference axis 51 with respect to the first polarization axis 52 (hereinafter referred to as “second direction”). The tilt angle operable in the first direction (that is, the maximum tilt angle) is increased, and the tilt angle in the second direction (that is, the maximum tilt angle) is decreased. The liquid crystal molecules LC of the present embodiment have such characteristics.

  FIG. 6 illustrates the liquid crystal molecules LC that are stable while being tilted to the left of the reference axis 51 when no drive voltage is applied. However, the ferroelectric liquid crystal material and the alignment films (33, 43) are illustrated. ), The liquid crystal molecules LC may be stabilized while being tilted to the right side of the reference axis 51. Even in this case, the tilt in the direction of the reference axis 51 is the first direction in which the tilt angle of the liquid crystal molecules LC is increased, and the tilt of the liquid crystal molecules LC is tilted in the direction away from the reference axis 51. It is defined as the second direction in which the corner is reduced.

  In addition, since the liquid crystal element 30 of the present embodiment has the above-described characteristics, the first polarization axis 52 and the second polarization axis are based on the stable state of the liquid crystal molecules LC sealed in the liquid crystal layer 35. 53, the first polarizing plate 32 and the second polarizing plate 42 are formed.

  The capacitor C is formed between the drain electrode of the source of the TFT 20 and a common electrode (not shown). The capacitor C holds a charge amount according to pixel data when the TFT 20 is ON, and applies a voltage as a drive voltage to the liquid crystal element 30 based on the charge held when the TFT 20 is OFF.

  The TFT 20 is used to supply pixel data supplied from the data line X to the capacitor C based on a scanning line control signal supplied from the scanning line Y. That is, the TFT 20 writes data to be applied to the liquid crystal element 30 indicated by a voltage corresponding to a predetermined value in the capacitor C.

  The scanning electrode Y is connected to the gate electrode of the TFT 20, and the data line X is connected to the source electrode. Further, one end of the liquid crystal element 30 and the capacitor C is connected to the drain electrode of the TFT 20.

[2.2] Driving Principle of Liquid Crystal Display Device Next, the driving principle of the liquid crystal display device 100 having the ferroelectric liquid crystal element 30 of the present embodiment will be described with reference to FIGS. FIG. 8 shows experimental results when the voltage level of the driving voltage is changed within a predetermined range of a predetermined reference potential in the liquid crystal molecules LC having V-shaped switching characteristics that are asymmetrical with respect to the positive and negative driving voltages. FIG. 9 is a graph showing experimental results for determining the range of the reference potential in the liquid crystal molecules in the present embodiment. FIG. 10 is a graph showing the experimental results of FIG. 9 based on the relationship between the transmitted light intensity and the input voltage.

  The driving method of the liquid crystal display device 100 according to the present embodiment is a driving method for displaying an image on the display panel 110 provided on the front surface of the illumination device 140, and is supplied to each pixel 10 by the data line driving circuit 120. Based on the pixel data, a driving voltage for driving the liquid crystal molecules LC is applied to each liquid crystal molecule LC.

  In the present embodiment, the voltage level and polarity of the applied drive voltage (the voltage held in the capacitor C) are controlled in order to control the transmitted light intensity in each pixel 10 of the light emitted from the illumination device 140. Accordingly, with respect to the first polarization axis 52, the inclination of the liquid crystal molecules LC in the first direction moving in the direction of the reference axis 51, and the liquid crystal molecules LC in the second direction moving in the direction away from the reference axis 51. Control the slope of the.

  In the present embodiment, the voltage level of the driving voltage applied to the corresponding liquid crystal molecule LC during driving of each liquid crystal molecule LC is within a predetermined reference potential range (including “0V”). In the case of changing to, the drive voltage to be applied is tilted in the second direction from the first polarization axis 52, and then the drive voltage to be applied is changed within a predetermined range of the reference potential.

  In particular, when the voltage level of such a drive voltage is changed within a predetermined range of a predetermined reference potential, and the liquid crystal molecules LC are further inclined from the first polarization axis 52 in the first direction. First, a driving voltage for tilting further in the second direction from the first polarization axis 52 is applied, and then the driving voltage to be applied is changed within a predetermined range of the reference potential.

  In general, when liquid crystal molecules LC having V-shaped switching characteristics that are asymmetrical with respect to positive and negative drive voltages are controlled within a predetermined range of the reference potential, that is, to block transmission of light emitted from the illumination device 140. In this case, the liquid crystal molecules LC are controlled to be in a stable state by applying no drive voltage to the side where the tilt angle is larger than the case where the drive voltage to be applied is changed from no side to the non-application side. When the drive voltage to be applied is changed to no application, the tilt of the liquid crystal molecules LC does not quickly return to the stable state of the no application state.

  That is, compared with the case where the driving voltage to be applied is changed to no application from the state where the liquid crystal molecules LC are inclined in the second direction with respect to the first polarization axis 52, the liquid crystal molecules LC are displaced from the first polarization axis 52. When changing the drive voltage to be applied from the state tilted in the first direction to no application, the tilt of the liquid crystal molecules LC does not quickly return parallel or substantially parallel to the first polarization axis. It is difficult to accurately “black” the display of the pixel 10 by blocking the light irradiated from (including making it close to blocking).

  For example, in the experimental results shown in FIGS. 8A and 8B, a driving voltage (input voltage) of 5 V formed by a rectangular wave for polarity inversion driving in which a positive voltage and a negative voltage of the same level appear alternately. It is assumed that the liquid crystal molecules LC of the present embodiment are driven using.

In this case, the polarity of the drive voltage becomes negative when the liquid crystal molecules LC of the present embodiment are driven and then the non-application state (that is, the drive voltage is “0 V” within the predetermined range of the reference potential). Compared with the case where the tilt angle is changed from the small side, when the tilt angle is changed from the large side where the polarity of the drive voltage is positive, as shown in FIGS. A considerable amount of time is required until the light intensity decreases to near “0”. In particular, when the tilt angle of the drive voltage is positive and the tilt angle is changed from the larger side, the transmitted light intensity is completely “even after 100 ms after the drive voltage is not applied. 0 ”and a luminance of about 200 cd / m ² is generated, and the light emitted from the lighting device 140 cannot be completely blocked.

  Therefore, in the present embodiment, as described above, when the drive voltage is changed within a predetermined range of the reference potential (including “0V”), the liquid crystal molecules LC are further moved in the second direction from the first polarization axis 52. After the drive voltage for tilting is applied to the liquid crystal molecules LC, the drive voltage to be applied is changed within a predetermined range of the reference potential. That is, when changing the driving voltage applied to the liquid crystal molecules LC within a predetermined range of a predetermined reference potential including “0 V”, the illumination device 140 is exemplified as shown in FIG. In order to completely block the irradiation from the above, the drive voltage is always changed from the first polarization axis 52 to the predetermined range of the reference potential from the state where it is further inclined in the second direction.

  In the present embodiment, the predetermined range of the reference potential includes a voltage at which the liquid crystal molecules LC are in a stable state when no drive voltage is applied and a voltage equivalent thereto, and a grayscale level including the voltage level “0 V” of the drive voltage. A voltage level range in which the value is equal to or less than a threshold value (that is, a black voltage in the liquid crystal display device 100). That is, the predetermined range of the reference potential is a voltage having a transmitted light intensity equal to or less than a predetermined value (for example, “1/50”) with respect to the transmitted light intensity of the maximum voltage level (for example, “± 5 V”) of the drive voltage. The range.

  For example, in the present embodiment, the predetermined range of the reference potential includes “0 V” based on the experimental results performed on the liquid crystal molecules LC illustrated in FIG. The voltage range is “0.5 V” to “0.03 V”. Specifically, in the present embodiment, from a predetermined drive voltage (−5V) to “−1.0V” to “0V” on each of the negative electrode side and the positive electrode side as shown in FIG. 9 (FIG. 9). (A)), or driving voltages of each voltage level from “0.4 V” to “0 V” (FIG. 9B) are input, and the driving voltage is determined based on the transmitted light intensity at that time. In the present embodiment, as shown in FIG. 10, the voltage level of the drive voltage at which the transmitted light intensity is 1/50 (= 0.02) or less based on FIGS. 9A and 9B. A predetermined range of the reference potential is defined as “−0.5 V” to “0.03 V”.

[2.3] Operation of Liquid Crystal Molecule LC of Ferroelectric Liquid Crystal Based on Driving Voltage Next, the operation of each liquid crystal molecule LC of the ferroelectric liquid crystal based on the driving voltage of this embodiment will be described with reference to FIG. FIG. 11 is a flowchart showing the operation of each liquid crystal molecule LC of the ferroelectric liquid crystal based on the driving voltage of the present embodiment.

  In this operation, the capacitor C basically holds the corresponding drive voltage. Depending on the pixel data, the drive voltage is within a predetermined range of a predetermined reference potential including “0 V”. Is held.

  The liquid crystal molecules LC of the ferroelectric liquid crystal in this operation are assumed to have V-shaped switching characteristics that are asymmetrical with respect to the positive and negative drive voltages shown in FIGS. 6 and 7, and the first polarization axis 52 is used as a reference. In order to incline the liquid crystal molecules LC in the first direction that moves in the direction of the reference axis 51, a positive drive voltage is applied, and the liquid crystal molecules LC move in the second direction that moves away from the reference axis 51. In order to incline, a negative drive voltage is applied.

  In such a situation, the drive voltage held in the capacitor C is not within a predetermined range of a predetermined reference potential including “0 V” (No in step S101), and the polarity of the drive voltage is positive. In this case (Yes in step S102), the liquid crystal molecules LC are further tilted in the second direction from the first polarization axis 52 from the reference axis 51 side with respect to the first polarization axis 52 in accordance with the drive voltage (step S103). ).

  On the other hand, when the drive voltage held in the capacitor C is not within a predetermined range of a predetermined reference potential including “0 V” (No in step S101), the polarity of the drive voltage is negative. (Step S102 No), the liquid crystal molecules LC are further tilted in the first direction from the first polarization axis 52 from the opposite side (second direction side) to the reference axis 51 with respect to the first polarization axis 52 according to the drive voltage. (Step S104).

  On the other hand, when the driving voltage held in the capacitor C is within a predetermined range of a predetermined reference potential including “0 V” (Yes in step S101), the liquid crystal molecules LC are changed according to the driving voltage. The first polarization axis 52 is parallel or substantially parallel to the first polarization axis 52 from the side opposite to the reference axis 51 (step S105).

[2.4] Pixel Data Generation Method According to this Embodiment Next, a pixel data generation method according to this embodiment will be described with reference to FIGS. 12 and 13. FIG. 12 and FIG. 13 are diagrams for explaining the pixel data generation method of the present embodiment (at the time of 1 × speed driving or at the time of 2 × speed driving).

  In the present embodiment, in the liquid crystal molecule LC that is driven and controlled by polarity inversion driving, the voltage level of the driving voltage is within a predetermined reference potential range (including “0 V”) for displaying “black”. As described above, a driving voltage for further tilting from the first polarization axis 52 in the second direction is applied to the liquid crystal molecules LC (for example, a negative driving voltage is applied), and then applied. The drive voltage to be changed is changed within a predetermined range of the reference potential. Therefore, it is necessary to generate pixel data for applying a driving voltage to the liquid crystal molecules LC in this way.

  Therefore, when the control circuit 170 of the present embodiment generates matrix data from the image data stored for each frame in the memory circuit 150, the drive voltage to be applied to the liquid crystal molecules LC is determined in advance from a positive polarity. When it is detected that the reference potential is changed within a predetermined range (including “0 V”), the voltage value of the pixel data of the corresponding frame or field is further changed from the first polarization axis 52 to the liquid crystal molecule LC. The driving voltage for tilting in two directions (for example, a negative polarity driving voltage) is rewritten.

  Specifically, the control circuit 170 determines that the drive voltage to be applied to the liquid crystal molecules LC controlled by the polarity inversion drive causes the liquid crystal molecules LC to tilt further from the first polarization axis 52 in the second direction. If it is detected that the reference voltage is changed within a predetermined range of the reference potential (for example, a positive drive voltage), “plus” is set immediately before the drive voltage to be applied falls within the predetermined range of the reference potential. The detected frame or field pixel data is rewritten to a drive voltage “within a predetermined range of the reference potential”.

For example, the liquid crystal element 30 is driven to invert the polarity for each field, the drive voltage for tilting the liquid crystal molecules LC further from the first polarization axis 52 in the second direction is “minus”, and the liquid crystal molecules LC are further driven from the first polarization axis 52. Assume that the drive voltage for tilting in the first direction is “plus”. In this case,
(A1) In the first frame, the first field is “−1V”,
(A2) In the first frame, the second field is “+ 1V”,
(A3) In the second frame, the first field is “0 V (black display)”,
(A4) In the second frame, the first field is “0 V (black display)”, and
(A5) In the third frame, the first field is “0 V (black display)”
When the pixel voltage in which the drive voltage to be applied to the liquid crystal molecules LC changes in this order is the control circuit 170, the pixel data in the field (A2) is rewritten to “0V”,
(B1) In the first frame, the first field is “−1V”,
(B2) In the first frame, the second field is “0 V (black display)”,
(B3) The first field is “0V (black display)” in the second frame, and (B4) the first field is “0V (black display)” in the second frame.
Generate pixel data for.

  In particular, the drive voltage of each field is formed by a plurality of pulses (for example, 6), and a voltage level (for example, “0V”) is included for black display in one of the plurality of pulses. In the case where the pixel data is as shown in (A1) to (A4) (for example, in the case of the 1 × speed driving in which the image data is displayed as it is for each frame), FIG. As shown, the fifth pulse in the first field of the second frame is NG. Therefore, in such a case, as shown in FIG. 12B, in the second field of the first frame, the value of the fifth pulse that is a negative polarity pulse is rewritten to “0V”, and (A3 ) To eliminate the pulse structure of the first field of the second frame which becomes NG by ½ frame ahead, and the pixel data of (B1) to (B3) are generated. The pixel data (B4) is also generated in the same manner.

  FIG. 12 shows pixel data for each frame in which polarity inversion driving is performed every ½ frame (field) and polarity inversion driving is performed for a plurality of pulses in each field. In addition, when the driving voltage of one field is defined in the pixel data, when the voltage level is present in order to display black in one pulse among the plurality of pulses, the field displays “black”. Will be executed. However, the polarity of the pulse advanced by 1/2 frame is inverted.

  In FIG. 12B, a field where the driving voltage other than within the predetermined range of the reference potential is switched to 0 V within the predetermined range of the reference potential (the field of (3) in the case of FIG. 12A). In the other fields (field (4) in the case of FIG. 12A), even if a pulse of “0V” is present from the positive polarity pulse, the drive voltage of the immediately preceding field is “0V”. And the drive voltage of the field is “0 V”, so there is no effect.

  On the other hand, instead of the above method, the control circuit 170 converts the configuration of the pixel data itself of the frame or field in which the driving voltage to be applied is detected within the predetermined range of the reference potential into the liquid crystal molecule LC. You may rewrite so that it may become the drive voltage (for example, minus drive voltage) for inclining further in the 2nd direction from the 1st polarization axis 52.

For example, the liquid crystal element 30 is driven to invert the polarity for each field, the drive voltage for tilting the liquid crystal molecules LC further from the first polarization axis 52 in the second direction is “minus”, and the liquid crystal molecules LC are further driven from the first polarization axis 52. Assume that the drive voltage for tilting in the first direction is “plus”. In this case,
(C1) In the first frame, the first field is “−1V”,
(C2) In the first frame, the second field is “+ 1V”,
(C3) In the second frame, the first field is “0 V (black display)”, and
(C4) The first field is “0 V (black display)” in the second frame.
If the drive voltage to be applied to the liquid crystal molecules LC changes in this order, the control circuit 170 rewrites the pulse configuration of the pixel data in the field (C3).

  That is, if a voltage level (for example, “0 V”) is included in one pulse among a plurality of pulses and the voltage level (for example, “0 V”) is included, the corresponding field is displayed as “black”. As shown in B), in the first field of the second frame, the value of the fifth pulse, which is a negative polarity pulse, is rewritten to a value outside the predetermined range of the reference potential.

  In such a case, it is used in the case of double speed driving in which an image between frames is generated as image data and the image data frame and the generated frame are displayed as one frame. In FIG. 13, d (n) is the nth frame in the image data, d (n + 1) is the n + 1th field in the image data, and in the case of double speed driving, (d (n) + d (N + 1)) / 2 generates data in a field between d (n) and d (n + 1). Further, in this case, as shown in FIG. 12, the drive voltage of each field is formed by a plurality of pulses (for example, 6), and black is displayed in one of the plurality of pulses. It is assumed that a voltage level (for example, “0V”) is included.

  As described above, the driving method of the liquid crystal display device 100 and the liquid crystal display device 100 according to the present embodiment are always the voltage level of the driving voltage applied to the liquid crystal molecules LC from the side with the small tilt angle in the liquid crystal molecules LC of the ferroelectric liquid crystal. Can be changed within a predetermined range of the reference potential.

  Therefore, the driving method of the liquid crystal display device 100 and the liquid crystal display device 100 according to the present embodiment always have the voltage level of the driving voltage applied to the liquid crystal molecules LC from the side with the small tilt angle in the liquid crystal molecules LC of the ferroelectric liquid crystal. Can be changed within a predetermined range of the reference potential, the inclination of the liquid crystal molecules LC can be returned, and the liquid crystal molecules LC can be smoothly shifted to a state parallel or substantially parallel to the first polarization axis 52, and “Black” can be accurately displayed on the display panel 110.

[3] Modification [3.1] Modification 1
In the above embodiment, the data line driving circuit 120 generates pixel data for polarity inversion driving, but the liquid crystal element 30 may be driven without polarity inversion driving. In this case, the control circuit 170 detects the switching of the gradation value in each pixel 10 when generating the matrix data based on the image data stored in the memory circuit 150 in conjunction with the memory circuit 150. When the switching of the gradation value to the minimum gradation value (that is, the switching to the driving voltage within the predetermined range of the predetermined reference potential including “0V” described above) is detected, the switching is performed. The matrix data is rewritten so that the data immediately before is set to the polarity and value of a predetermined drive voltage that has a polarity for tilting the liquid crystal molecules LC further in the second direction from the first polarization axis 52.

[3.2] Modification 2
In the above embodiment, the pixel data immediately before the gradation value is switched always generates matrix data having a certain polarity (for example, negative polarity). However, whenever the gradation value of each pixel is switched, the matrix data is always generated. The matrix data may be generated so as to have a constant polarity only when the gradation value falls within a predetermined range of the reference potential without setting the constant polarity.

C: Capacitor R: Rubbing direction LC ... Liquid crystal molecule 10 ... Pixel 20 ... TFT
DESCRIPTION OF SYMBOLS 30 ... Liquid crystal element 31 ... 1st base material 32 ... 1st polarizing plate 33, 43 ... Orientation film 35 ... Liquid crystal layer 41 ... 2nd base material 42 ... 2nd polarizing plate 51 ... Reference axis 52 ... 1st polarizing axis 53 ... Second polarization axis 100 ... Liquid crystal display device 110 ... Display panel 120 ... Data line drive circuit 130 ... Scan line drive circuit 140 ... Illumination device 150 ... Memory circuit 170 ... Control circuit

Claims (8)

A first polarizing plate having a first polarization axis;
A second polarizing plate having a second polarization axis non-parallel to the first polarization axis;
A pair of alignment films sandwiched between the first polarizing plate and the second polarizing plate and rubbed in a direction of a reference axis non-parallel to the first polarization axis and the second polarization axis;
A liquid crystal layer sandwiched between the alignment films, which is tilted and stabilized so as to be parallel to one polarization axis when no driving voltage is applied, and encloses liquid crystal molecules having spontaneous polarization;
A display panel driving method for displaying an image on a display panel provided in front of a light source,
(A) A driving voltage is applied to each liquid crystal molecule based on the image data input by the driving circuit,
(B) In order to control the transmitted light intensity at each pixel of the light emitted from the light source, the reference axis is set based on the first polarization axis according to the voltage level and polarity of the applied drive voltage. Controlling the tilt of the liquid crystal molecules in a first direction moving in a direction and the tilt of the liquid crystal molecules in a second direction moving in a direction away from the reference axis;
(C) When changing the voltage level of the driving voltage applied to the corresponding liquid crystal molecule during driving of each liquid crystal molecule to be within a predetermined range (including “0V”) of a predetermined reference potential. After the driving voltage for tilting the liquid crystal molecules further in the second direction from the first polarization axis is applied to the liquid crystal molecules, the driving voltage to be applied is changed within a predetermined range of the reference potential. , Display panel drive method. The driving voltage of the corresponding liquid crystal molecule is changed within a predetermined range (including “0V”) of the reference potential during driving of each liquid crystal molecule, and the corresponding liquid crystal molecule is changed to the first polarization axis. In the case of tilting toward the first direction,
The driving voltage for tilting the liquid crystal molecules further in the second direction from the first polarization axis is applied to the liquid crystal molecules, and then the driving voltage to be applied is changed within a predetermined range of the reference potential. 2. A method for driving a display panel according to 1.   The driving voltage applied to the corresponding liquid crystal molecules in the second direction further from the first polarization axis is applied when the liquid crystal molecules are tilted from the first polarization axis in the first direction. The display panel driving method according to claim 2, wherein the display panel is a voltage having a reverse polarity of the voltage. Based on the input image data, a driving voltage whose polarity is inverted at a predetermined cycle is applied to each liquid crystal molecule,
4. The polarity according to claim 3, wherein the polarity immediately before the drive voltage when changing the reference potential within a predetermined range is a voltage polarity for further tilting liquid crystal molecules in the second direction from the first polarization axis. 5. Driving method of display panel.   5. The maximum tilt angle of liquid crystal molecules in the second direction is smaller than the maximum tilt angle of liquid crystal molecules in the first direction with respect to the reference axis. 6. Driving method of display panel.   The method for driving a display panel according to claim 1, wherein the liquid crystal molecules have ferroelectric properties. The drive circuit is
When generating the image data based on the data stored in the storage means, when the drive voltage applied to the liquid crystal molecules changes within a predetermined range (including “0 V”) of the reference potential. Detecting whether or not the drive voltage applied to the liquid crystal molecules immediately before is a drive voltage for further tilting the liquid crystal molecules in the first direction from the first polarization axis;
When the immediately preceding drive voltage is a drive voltage for tilting the liquid crystal molecules further in the first direction from the first polarization axis, the immediately preceding drive voltage is further increased from the first polarization axis in the second direction. The display panel drive method according to claim 1, wherein the drive voltage is rewritten to a drive voltage for tilting liquid crystal molecules. A display device for displaying an image on a display panel having a plurality of pixels provided in front of a light source,
Each pixel is
A first polarizing plate having a first polarization axis;
A second polarizing plate having a second polarization axis non-parallel to the first polarization axis;
A pair of alignment films sandwiched between the first polarizing plate and the second polarizing plate and rubbed in a direction of a reference axis non-parallel to the first polarization axis and the second polarization axis;
A liquid crystal layer sandwiched between the alignment films, which is tilted and stabilized so as to be parallel to one polarization axis when no driving voltage is applied, and encloses liquid crystal molecules having spontaneous polarization;
And composed of
A drive circuit for applying a drive voltage for driving the liquid crystal molecules to each liquid crystal molecule based on the input image data;
The drive circuit is
In order to control the transmitted light intensity at each pixel of the light emitted from the light source, the light is moved in the direction of the reference axis with respect to the first polarization axis according to the voltage level and polarity of the applied drive voltage. Controlling the tilt of the liquid crystal molecules in the first direction and the tilt of the liquid crystal molecules in the second direction moving away from the reference axis,
When the voltage level of the driving voltage applied to the corresponding liquid crystal molecule is changed within a predetermined range (including “0V”) of a predetermined reference potential during driving of each liquid crystal molecule, the first polarized light A display device, wherein a driving voltage for tilting the liquid crystal molecules further in a second direction from the axis is applied to the liquid crystal molecules, and then the driving voltage is changed within a predetermined range of the reference potential.

Images