JP2012155079A - Liquid crystal shutter, driving method of liquid crystal shutter, and image display system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal shutter capable of determining a state of a liquid crystal shutter without newly adding a component, and to provide a driving method of the liquid crystal shutter, and an image display system including the liquid crystal shutter.SOLUTION: The liquid crystal shutter includes: a first liquid crystal panel and a second liquid crystal panel of OCB mode; a power supply section capable of outputting an initial voltage Va and a pulsing normal voltage Vd for alternatingly switching between a transmission state and a non-transmission state; a receiver capable of receiving a synchronizing signal; and a driving section. After performing an initial transition by using the initial voltage Va, the driving section performs the normal driving for applying the normal voltage Vd to the first liquid crystal panel and the second liquid crystal panel respectively associated with the synchronizing signal. When the reception of the synchronizing signal by the receiver is stopped, the driving section performs a retention driving for applying the initial voltage Va to the first liquid crystal panel and the second liquid crystal panel respectively.

Description

  Embodiments described herein relate generally to a liquid crystal shutter, a liquid crystal shutter driving method, and an image display system.

  In recent years, various techniques for displaying a stereoscopic image have been proposed. As the above technique, for example, a stereoscopic image display technique using an active shutter type liquid crystal shutter and a display device such as a time division type liquid crystal display device is known.

  The liquid crystal display device alternately displays a left-eye image and a right-eye image. The liquid crystal shutter switches the left-eye liquid crystal panel and the right-eye liquid crystal panel between a transmission state (on) and a non-transmission state (off) in conjunction with image display of the liquid crystal display device.

  While the liquid crystal display device displays the image for the left eye, the light emitted from the liquid crystal display device is transmitted through the liquid crystal panel for the left eye and blocked by the liquid crystal panel for the right eye. Similarly, while the liquid crystal display device displays an image for the right eye, the light emitted from the liquid crystal display device is blocked by the liquid crystal panel for the left eye and transmitted through the liquid crystal panel for the right eye.

  As a result, the user wearing the liquid crystal shutter sees the left-eye image and the right-eye image alternately with the left and right eyes, and sees the planar image displayed on the liquid crystal display device as a stereoscopic image. Can do. At this time, the liquid crystal shutter is normally driven in synchronization with an image displayed on the liquid crystal display device based on a synchronization signal transmitted from the liquid crystal display device.

  Further, in normal driving, high frequency driving corresponding to 120 Hz is required, and since a high response speed is required for the liquid crystal shutter, it is desirable to use OCB (Optically Compensated Bend) liquid crystal.

JP-A-10-191399 JP 2000-275575 A JP 2007-110683 A

  Conventionally, since normally white liquid crystal is used for the liquid crystal shutter, it is difficult to determine whether the liquid crystal shutter is operating. In addition, even if the synchronization signal is interrupted, it is considered that the liquid crystal shutter is allowed to maintain its own operation for a predetermined period (holding drive state). It cannot be determined whether the drive state is the holding drive state or the normal operation state.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a liquid crystal shutter capable of determining the state of the liquid crystal shutter without adding a new component, a liquid crystal shutter driving method, and an image including the liquid crystal shutter. To provide a display system.

The liquid crystal shutter according to one embodiment
An OCB mode first liquid crystal panel having a pair of electrode substrates and a liquid crystal layer sandwiched between the electrode substrates, covering the field of view of the left eye, and capable of controlling the transmittance of light incident on the left eye;
An OCB mode second liquid crystal panel having a pair of electrode substrates and a liquid crystal layer sandwiched between the electrode substrates, covering the field of view of the right eye, and capable of controlling the transmittance of light incident on the right eye;
An initial voltage for initial transition of liquid crystal molecules in the respective liquid crystal layers of the first liquid crystal panel and the second liquid crystal panel from a splay alignment to a bend alignment, and a voltage level relatively set lower than the initial voltage; A power supply unit capable of outputting a pulse-like normal voltage for alternately switching between a transmissive state and a non-transmissive state in a state where the liquid crystal molecules adopt the bend alignment in each of the first liquid crystal panel and the second liquid crystal panel;
A receiver capable of receiving a synchronization signal;
The initial voltage is applied to each of the first liquid crystal panel and the second liquid crystal panel to perform the initial transition, and then the normal voltage is associated with the synchronization signal to each of the first liquid crystal panel and the second liquid crystal panel. A drive unit that performs normal drive to be applied to
When reception of the synchronization signal at the receiver is interrupted, the driving unit performs holding driving to apply the initial voltage to each of the first liquid crystal panel and the second liquid crystal panel.

In addition, the liquid crystal shutter driving method according to the embodiment includes:
An OCB mode first liquid crystal panel having a pair of electrode substrates and a liquid crystal layer sandwiched between the electrode substrates, covering the field of view of the left eye and controlling the transmittance of light incident on the left eye, and a pair of electrodes An OCB mode second liquid crystal panel having a liquid crystal layer sandwiched between the substrate and the electrode substrate, covering the field of view of the right eye, and capable of controlling the transmittance of light incident on the right eye, the first liquid crystal panel, An initial voltage for initial transition of liquid crystal molecules in each liquid crystal layer of the second liquid crystal panel from splay alignment to bend alignment, and a voltage level relatively shallower than the initial voltage are set, and the first liquid crystal panel and the second liquid crystal panel A power supply unit capable of outputting a normal pulse voltage for alternately switching between a transmissive state and a non-transmissive state with the liquid crystal molecules adopting the bend orientation of each liquid crystal panel, and receiving a synchronization signal A receiver, in the driving method of a liquid crystal shutter having a
The initial voltage is applied to each of the first liquid crystal panel and the second liquid crystal panel to perform the initial transition, and then the normal voltage is associated with the synchronization signal to each of the first liquid crystal panel and the second liquid crystal panel. The normal drive applied to the
When reception of the synchronizing signal at the receiver is interrupted, holding driving is performed to apply the initial voltage to each of the first liquid crystal panel and the second liquid crystal panel.

An image display system according to an embodiment includes:
An OCB mode first liquid crystal panel having a pair of electrode substrates and a liquid crystal layer sandwiched between the electrode substrates, covering the field of view of the left eye and controlling the transmittance of light incident on the left eye, and a pair of electrodes An OCB mode second liquid crystal panel having a liquid crystal layer sandwiched between the substrate and the electrode substrate, covering the field of view of the right eye, and capable of controlling the transmittance of light incident on the right eye, the first liquid crystal panel, An initial voltage for initial transition of liquid crystal molecules in each liquid crystal layer of the second liquid crystal panel from splay alignment to bend alignment, and a voltage level relatively shallower than the initial voltage are set, and the first liquid crystal panel and the second liquid crystal panel A power supply unit capable of outputting a normal pulse voltage for alternately switching between a transmissive state and a non-transmissive state with the liquid crystal molecules adopting the bend orientation of each liquid crystal panel, and receiving a synchronization signal A receiver, and applying the initial voltage to each of the first liquid crystal panel and the second liquid crystal panel to perform the initial transition; then, associating the normal voltage with the synchronization signal, the first liquid crystal panel and the second liquid crystal panel A liquid crystal shutter comprising: a drive unit that performs normal driving to be applied to each of the liquid crystal panels;
A display device for displaying an image and transmitting the synchronization signal suitable for the image information to the liquid crystal shutter,
When reception of the synchronization signal at the receiver is interrupted, the driving unit performs holding driving to apply the initial voltage to each of the first liquid crystal panel and the second liquid crystal panel.

FIG. 1 is a schematic configuration diagram illustrating an image display system according to an embodiment. FIG. 2 is a schematic configuration diagram showing the liquid crystal shutter shown in FIG. FIG. 3 is a cross-sectional view showing the first liquid crystal panel shown in FIGS. 1 and 2. FIG. 4 is a cross-sectional view of the first liquid crystal panel, showing the alignment state of liquid crystal molecules when the first liquid crystal panel is in a transmissive state. FIG. 5 is a cross-sectional view of the first liquid crystal panel, showing the alignment state of liquid crystal molecules when the first liquid crystal panel is in a non-transmissive state. FIG. 6 is a cross-sectional view schematically showing the liquid crystal display device shown in FIG. FIG. 7 is a schematic configuration diagram showing a part of the array substrate shown in FIG. FIG. 8 shows an image display of the liquid crystal display device of the image display system, ON / OFF of the first liquid crystal panel, ON / OFF of the second liquid crystal panel, a drive voltage applied to the first liquid crystal panel, 2 is a timing chart showing drive voltages applied to a liquid crystal panel. FIG. 9 is a timing chart showing drive voltages applied to the first liquid crystal panel. FIG. 10 is a graph showing a change in light transmittance with respect to a voltage value applied to the first liquid crystal panel. FIG. 11 is a block diagram schematically showing a part of the liquid crystal display device. FIG. 12 is a block diagram schematically showing a receiver of the liquid crystal shutter. FIG. 13 is a timing chart showing signal waveforms of respective parts of the receiver. (1) Phase synchronization signal a, (2) pulse signal b, (3) switch control pulse signal c, (4) signal d, ( 5) Signal e, (6) Signal f, (7) Signal g, (8) Second liquid crystal panel drive signal h, (9) First liquid crystal panel drive signal i, (10) First liquid crystal panel and second liquid crystal It is a figure which shows the sequence of the opening / closing sequence of a panel, and (11) the image | video displayed on a liquid crystal display device.

Hereinafter, an image display system including a liquid crystal shutter and a method for driving the liquid crystal shutter according to an embodiment will be described in detail with reference to the drawings. First, the configuration of the image display system will be described.
As shown in FIG. 1, the image display system includes an active shutter type liquid crystal shutter 1 and a liquid crystal display device 2 as a display device.

  As shown in FIGS. 1 to 3, the liquid crystal shutter 1 includes a first liquid crystal panel 3L, a second liquid crystal panel 3R, a glasses frame 4, a drive unit 5, a power supply unit 6, a receiver 7, a housing. A body 8 and a timer 9 are provided. In this embodiment, the liquid crystal shutter 1 is a glasses-mounted liquid crystal shutter.

The first liquid crystal panel 3L includes a pair of electrode substrates 10 and 20 and a liquid crystal layer 30 sandwiched between the electrode substrates.
The electrode substrate 10 includes a glass substrate 11 as a transparent insulating substrate, a first electrode 12 formed on the glass substrate 11, and an alignment film 13 formed on the glass substrate 11 and the first electrode 12. doing. As the insulating substrate, a plastic substrate or a resin film can be used in addition to the glass substrate. An optical compensation film 14 and a polarizing plate 15 are disposed on the electrode substrate 10. The optical compensation film 14 and the polarizing plate 15 are located on the opposite side of the first electrode 12 with respect to the glass substrate 11, and are sequentially disposed on the outer surface of the glass substrate 11.

  The electrode substrate 20 has a glass substrate 21 as a transparent insulating substrate, a second electrode 22 formed on the glass substrate 21, and an alignment film 23 formed on the glass substrate 21 and the second electrode 22. doing. Similarly, as the insulating substrate, a plastic substrate or a resin film can be used in addition to the glass substrate. An optical compensation film 24 and a polarizing plate 25 are disposed on the electrode substrate 20. The optical compensation film 24 and the polarizing plate 25 are located on the opposite side of the second electrode 22 with respect to the glass substrate 21 and are sequentially disposed on the outer surface of the glass substrate 21.

  The first electrode 12 and the second electrode 22 are made of, for example, ITO (indium tin oxide) as a transparent conductive material. The alignment film 13 and the alignment film 23 are subjected to alignment treatment (rubbing) in the same direction. The polarizing plate 15 and the polarizing plate 25 are arranged in crossed Nicols so as to intersect at approximately 45 ° with respect to the alignment direction.

  The electrode substrate 10 and the electrode substrate 20 are arranged to face each other while holding a predetermined gap by a plurality of spherical spacers 31 as a plurality of spacers, and are joined to each other by a sealing material 32 arranged at the peripheral edge of both substrates. . In place of the spherical spacer 31, a columnar spacer can be integrally formed on one substrate. The liquid crystal layer 30 is formed of nematic liquid crystal filled in a region surrounded by the electrode substrate 10, the electrode substrate 20, and the sealing material 32.

  As described above, the first liquid crystal panel 3L is an OCB (optically compensated bend) mode liquid crystal panel in which the optical compensation films 14 and 24 are combined with the π cell. Here, the first liquid crystal panel 3L is a normally white type that enters a light transmission state when no voltage is applied. The first liquid crystal panel 3L covers the field of view of the left eye and can control the transmittance of light incident on the left eye.

  A pulsed normal voltage Vd is applied to the first electrode 12 and a voltage Vcom is applied to the second electrode 22, whereby a pulsed drive voltage (normal voltage) is applied to the liquid crystal layer 30. As shown in FIGS. 2, 4, and 5, an initial voltage Va of about 20 V is applied to the first electrode 12 and a voltage Vcom is applied to the second electrode 22. Voltage) is applied, and the liquid crystal molecules 30m transition from the splay alignment to the bend alignment (initial transition). Then, by applying a desired drive voltage (regular voltage) to the liquid crystal layer 30, the first liquid crystal panel 3L can be switched between the transmissive state and the non-transmissive state while maintaining the bend alignment of the liquid crystal molecules 30m. The first liquid crystal panel 3L is excellent in high-speed response due to bend alignment and flow effect.

  As shown in FIGS. 1 to 3, the second liquid crystal panel 3R is formed in the same manner as the first liquid crystal panel 3L. The second liquid crystal panel 3R includes a pair of electrode substrates 10 and 20 and a liquid crystal layer 30 sandwiched between the electrode substrates, covers the right eye field of view, and can control the transmittance of light incident on the right eye. Mode LCD panel. Here, the second liquid crystal panel 3R is a normally white type that enters a light transmission state when no voltage is applied.

In the first liquid crystal panel 3L and the second liquid crystal panel 3R, although not shown, their shapes and the positions of terminals formed on them may be different from each other. It is possible to identify whether the second liquid crystal panel 3R is for the left eye or for the right eye.
As shown in FIG. 1, the first liquid crystal panel 3L and the second liquid crystal panel 3R are attached to the spectacle frame 4.

  The power supply unit 6, the receiver 7 and the timer 9 are connected to the drive unit 5. The power supply unit 6 supplies power to the drive unit 5. The power supply unit 6 can output an initial voltage Va, a normal voltage Vd, and a voltage Vcom. The receiver 7 can receive data (synchronization signal) by wired or wireless communication. The housing 8 accommodates the drive unit 5, the power supply unit 6, the receiver 7, and the timer 9, and is attached to the glasses frame 4.

The timer 9 can count the time when reception of the synchronization signal at the receiver 7 is interrupted.
The driving unit 5 applies the initial voltage Va to each of the first liquid crystal panel 3L and the second liquid crystal panel 3R to perform initial transition, and then associates the normal voltage Vd with the synchronization signal received by the receiver 7. Regular driving applied to each of the first liquid crystal panel 3L and the second liquid crystal panel 3R is performed.

When reception of the synchronization signal at the receiver 7 is interrupted, the driving unit 5 performs holding driving to apply the initial voltage Va to each of the first liquid crystal panel 3L and the second liquid crystal panel 3R.
When the time counted by the timer 9 reaches a specific time, the drive unit 5 stops applying the initial voltage Va to the first liquid crystal panel 3L and the second liquid crystal panel 3R.

  As shown in FIG. 2, in detail, the drive unit 5 electrically connects the first electrode 12 and the second electrode 22 of the first liquid crystal panel 3L and the second liquid crystal panel 3R through a flexible wiring board (FPC) or the like. It is connected to the. The drive unit 5 applies a pulsed normal voltage Vd and a voltage Vcom to the first liquid crystal panel 3L and the second liquid crystal panel 3R, respectively, and the first liquid crystal panel 3L (liquid crystal layer 30) and the second liquid crystal panel 3R (liquid crystal layer). 30) normal driving in which a driving voltage is applied, and initial voltage Va and voltage Vcom are applied to the first liquid crystal panel 3L (liquid crystal layer 30) and the second liquid crystal panel 3R (liquid crystal layer 30), respectively, and the liquid crystal molecules are bent. It is possible to switch between holding driving for holding the state of adopting the above.

By performing normal driving, the driving unit 5 can alternately switch the first liquid crystal panel 3L and the second liquid crystal panel 3R between a transmission state and a non-transmission state in a state where the liquid crystal molecules 30m have a bend alignment.
As described above, the liquid crystal shutter 1 is formed.

  As shown in FIGS. 1 and 6, the liquid crystal display device 2 includes a liquid crystal display panel 50, a backlight unit 90, and a control unit 100. The liquid crystal display panel 50 includes an array substrate 60, a counter substrate 70 disposed to face the array substrate 60, and a liquid crystal layer 80 sandwiched between the array substrate 60 and the counter substrate 70.

  As shown in FIGS. 6 and 7, the array substrate 60 includes a rectangular glass substrate 61 as a transparent insulating substrate. A plurality of signal lines 62 and a plurality of scanning lines 63 are formed on the glass substrate 61. The signal line 62 and the scanning line 63 are formed orthogonal to each other. A plurality of auxiliary capacitance lines 64 parallel to the scanning lines 63 are formed on the glass substrate 61. In this embodiment, a pixel PX is formed in each region surrounded by two adjacent signal lines 62 and two adjacent scanning lines 63. These pixels PX are arranged in a matrix on the glass substrate 61.

Next, one pixel PX is taken out and described in detail.
The pixel PX includes a TFT (thin film transistor) 65 as a switching element formed near the intersection of the signal line 62 and the scanning line 63, a pixel electrode 66 connected to the TFT 65, and an auxiliary capacitance element connected to the pixel electrode 66. 67. The auxiliary capacitance line 64 forms one electrode of the auxiliary capacitance element 67.

  Although not shown, a color filter having a plurality of colored layers of red, green, and blue is formed on the glass substrate 61. The pixel electrode 66 is formed on the color filter with a transparent conductive material such as ITO. Further, for example, a plurality of columnar spacers 68 are formed on the color filter as spacers. As described above, the array pattern 60 </ b> P is formed on the glass substrate 61. An alignment film 69 is formed on the glass substrate 61 and the array pattern 60P.

  The counter substrate 70 includes a rectangular glass substrate 71 as a transparent insulating substrate. On the glass substrate 71, a counter electrode 72 and an alignment film 73 are sequentially formed. The alignment film 69 and the alignment film 73 are subjected to alignment treatment (rubbing) in the same direction. Thus, the counter substrate 70 is formed.

  A gap between the array substrate 60 and the counter substrate 70 is held by a plurality of columnar spacers 68. The array substrate 60 and the counter substrate 70 are bonded together by a sealing material 81 disposed along the outer periphery of the display area. The liquid crystal layer 80 is formed of nematic liquid crystal filled in a region surrounded by the array substrate 60, the counter substrate 70, and the sealing material 81.

  An optical compensation film 51 and a polarizing plate 52 are sequentially formed on the outer surface of the array substrate 60. On the outer surface of the counter substrate 70, an optical compensation film 53 and a polarizing plate 54 are sequentially formed. The polarizing plate 52 and the polarizing plate 54 are arranged in crossed Nicols so as to intersect at approximately 45 ° with respect to the alignment direction. As described above, the liquid crystal display panel 50 is an OCB mode liquid crystal panel. Here, the liquid crystal display panel 50 is a normally white type that enters a light transmission state when no voltage is applied.

  As shown in FIG. 6, the backlight unit 90 is provided on the outer surface side of the array substrate 60. The backlight unit 90 includes a light guide 92 including a light guide plate facing the polarizing plate 52, and a light source 93 and a reflector 94 made of, for example, a cold-cathode ray tube disposed opposite to one side edge of the light guide 92. is doing.

  Next, the liquid crystal shutter 1 of the image display system and the driving method of the liquid crystal shutter 1 will be described. The liquid crystal shutter 1 and the driving method of the liquid crystal shutter 1 are assumed when the synchronization signal transmitted from the liquid crystal display device 2 to the liquid crystal shutter 1 is interrupted due to some trouble when a stereoscopic image is displayed using the image display system. In this case, the drive unit 5 is switched from the normal drive to the holding drive.

First, the operation of the liquid crystal shutter 1 and the liquid crystal display device 2 performed when displaying a stereoscopic image using the image display system, in particular, normal driving by the driving unit 5 will be described.
As shown in FIGS. 6 and 8, the control unit 100 controls the driving of the liquid crystal display panel 50 so as to alternately display the left-eye image and the right-eye image at a frame frequency of 120 Hz. Here, one frame (1F) is a time period for sequentially scanning all the pixels PX and again scanning the same pixel PX.

  From the above, the liquid crystal display device 2 can display a stereoscopic image at a frequency of substantially 60 Hz without a decrease in resolution.

  The driving unit 5 applies a pulsed normal voltage Vd and a voltage Vcom to the first liquid crystal panel 3L and the second liquid crystal panel 3R, and the liquid crystal molecules 30m bend in the first liquid crystal panel 3L and the second liquid crystal panel 3R, respectively. In the picked state, normal driving is performed to switch alternately between a transmissive state and a non-transmissive state.

  Specifically, as shown in FIGS. 1, 2, and 8, the drive unit 5 holds the first liquid crystal panel 3 </ b> L in synchronization with the right-eye image display by the liquid crystal display device 2 during an arbitrary one frame period. While switching to the transmission state (OFF), the second liquid crystal panel 3R is switched to the transmission state (ON). During this frame period, the transmittance of the first liquid crystal panel 3L is approximately 0%.

  Subsequently, during the period of one frame, the driving unit 5 switches the second liquid crystal panel 3R while switching the first liquid crystal panel 3L to the transmission state (ON) in synchronization with the image display for the left eye by the liquid crystal display device 2. Switch to the non-transmissive state (OFF). When the first liquid crystal panel 3L is switched to the transmission state (ON), the first liquid crystal panel 3L exhibits high-speed response, and the transmittance of the first liquid crystal panel 3L increases from 0%. Therefore, the first liquid crystal panel 3L is in a transmissive state during this frame period.

  Thereafter, the first liquid crystal panel 3L and the second liquid crystal panel 3R are alternately switched to the transmission state in synchronization with the image display of the liquid crystal display device 2. When the driving unit 5 switches the first liquid crystal panel 3L and the second liquid crystal panel 3R to the transmissive state (ON), respectively, the driving unit 5 is switched after 1/60 second from the previous switching to the transmissive state (ON). Thus, the user wearing the liquid crystal shutter 1 can alternately view the left-eye image and the right-eye image with the left and right eyes, and can display a stereoscopic image to the user.

  Next, a method for driving the liquid crystal shutter 1 when a stereoscopic image is displayed using the image display system will be described. In particular, the operation of the liquid crystal shutter 1 (holding drive by the drive unit 5) performed when the synchronization signal transmitted from the liquid crystal display device 2 to the liquid crystal shutter 1 is interrupted due to some trouble will be described. The holding drive of the liquid crystal shutter 1 also holds the liquid crystal molecules 30m in a bend alignment state.

  As shown in FIGS. 2, 3, and 9, the driving unit 5 applies the initial voltage Va and the voltage Vcom to the first liquid crystal panel 3 </ b> L and the second liquid crystal panel 3 </ b> R, respectively, and performs initial driving. Migrate to

  During a normal driving period in which normal driving is performed, the driving unit 5 applies the normal voltage Vd and the voltage Vcom to the first liquid crystal panel 3L and the second liquid crystal panel 3R in association with the synchronization signal. The frequency of the normal voltage Vd is set to 120 Hz.

During the normal driving period, the driving unit 5 performs polarity inversion driving that inverts the polarity of the normal voltage Vd applied to the first liquid crystal panel 3L (first electrode 12).
The driving unit 5 applies a pulsed normal voltage Vd that can alternately apply the voltage VBH and the voltage VBL at equal intervals to the first electrode 12 of the first liquid crystal panel 3L, and applies a voltage Vcom of 0 V to the second electrode 22. Apply. The second electrode 22 is always set to the ground potential.

  The voltage VBH and the voltage VBL are set deeper than the critical voltage (threshold voltage) at which the liquid crystal molecules 30m reversely transition from bend alignment to splay alignment. In other words, the absolute values of the voltage VBH and the voltage VBL are greater than or equal to the absolute value of the critical voltage.

The normal voltage Vd is set to have a relatively shallow voltage level than the initial voltage Va. Here, when the normal voltage Vd is relatively shallower than the initial voltage Va, it can be said that the absolute value of the normal voltage Vd is relatively smaller than the absolute value of the initial voltage Va.
During the holding driving period, the driving unit 5 holds and drives the second liquid crystal panel 3R in the same manner as the first liquid crystal panel 3L.

  When reception of the synchronization signal at the receiver 7 is interrupted, the driving unit 5 switches from normal driving to holding driving. The timer 9 starts counting time. In the holding driving period in which holding driving is performed, the driving unit 5 applies the initial voltage Va and the voltage Vcom to the first liquid crystal panel 3L and the second liquid crystal panel 3R, respectively. The initial voltage Va is a constant voltage, and is always applied to each of the first liquid crystal panel 3L and the second liquid crystal panel 3R during the holding drive period.

  During the holding drive period, the drive unit 5 can maintain the bend alignment of the first liquid crystal panel 3L and the second liquid crystal panel 3R. For this reason, when the reception of the synchronization signal at the receiver 7 is resumed (returned), the drive unit 5 can immediately switch from the holding drive to the normal drive, and the normal drive associated with the synchronization signal is performed. It is possible to resume the operation, thereby ensuring the operational stability.

  In addition, when the time counted by the timer 9 reaches the specific time, such as when the synchronization signal from the liquid crystal display device 2 does not return to the state in which the liquid crystal shutter 1 can receive even after a specific time, for example, 1 minute has passed. The driving unit 5 stops application of the initial voltage Va to the first liquid crystal panel 3L and the second liquid crystal panel 3R, and stops driving the first liquid crystal panel 3L and the second liquid crystal panel 3R.

  In the above-described embodiment, the voltage Vcom of 0 V is always applied to the second electrode 22, but a voltage having an opposite phase to the voltage applied to the first electrode 12 can also be applied. In this case, there is an advantage that the amplitude of the voltage applied to each electrode can be reduced. In this case, the voltage applied to one of the electrodes may be controlled, or the voltage applied to both the electrodes 12 and 22 may be controlled.

Next, the transmittance in the normal driving period and the transmittance in the holding driving period will be described.
As shown in FIG. 10, it can be seen that the light transmittance of the first liquid crystal panel 3L and the second liquid crystal panel 3R changes according to the applied voltage value. The transmittance T2 in the holding drive period is lower than the transmittance T1 in the normal drive period. Therefore, the drive unit 5 applies the initial voltage Va to each of the first liquid crystal panel 3L and the second liquid crystal panel 3R during the holding drive period, so that the transmittance in the holding drive period is different from the transmittance in the normal driving period. Therefore, it is possible to notify the user that the synchronization signal is interrupted.

  Next, the relationship between the liquid crystal shutter 1 and the liquid crystal display device 2 of the image display system of the above embodiment will be further described. Hereinafter, the liquid crystal shutter 1 that performs polarity inversion driving that inverts the polarity of the normal voltage Vd at least once in order to reduce flicker in each of the transmission state (ON) period and the non-transmission state (OFF) period will be described as an example. To do. The liquid crystal display device 2 can display a video (moving image) and a still image. Here, a case where the liquid crystal display device 2 displays a video will be described.

  As shown in FIG. 1, the liquid crystal display device 2 displays an image and simultaneously outputs a synchronization signal including identification information indicating whether the currently displayed image is a left-eye image or a right-eye image. As shown in FIGS. 1 and 2, the receiver 7 of the liquid crystal shutter 1 receives a synchronization signal matching the image information output from the liquid crystal display device 2 and transmits this signal to the drive unit 5. Accordingly, the driving unit 5 can synchronize the opening / closing operation of the first liquid crystal panel 3L and the second liquid crystal panel 3R with the left-eye video display and the right-eye video display of the liquid crystal display device 2.

FIG. 11 shows the configuration of the liquid crystal display device 2.
As shown in FIG. 11, the video signal for the left eye and the video signal for the right eye are input to the input terminal 110 of the liquid crystal display device 2. These signals may be either signals acquired from broadcast signals or signals reproduced from a recording medium. A video signal for planar video display is also input to the input terminal 110. Hereinafter, a case where a video signal for stereoscopic video display (a video signal for the left eye and a video signal for the right eye) is input will be described.

  The video signal input to the input terminal 110 is transmitted to the video signal processing circuit 111 and the synchronization signal processing circuit 113. The synchronization signal processing circuit 113 separates and outputs the horizontal synchronization signal H and the vertical synchronization signal V from the video signal.

  The horizontal synchronization signal H and the vertical synchronization signal V are input to the video signal processing circuit 111 and used as timing pulses for signal processing. The horizontal synchronization signal H and the vertical synchronization signal V are input to the display unit 112 of the liquid crystal display device 2 and are used as timing pulses for horizontal scanning and vertical scanning. The liquid crystal display device 2 alternately displays the left-eye video signal L and the right-eye video signal R output from the video signal processing circuit 111.

  Here, in part of the right-eye video signal R, for example, an R identification signal RID is inserted in a horizontal period that is immediately after a vertical blanking period and does not normally appear in the display area. The R identification signal RID is extracted by the video signal processing circuit 111. The R identification signal RID is input to the synchronization signal transmission circuit 114. The vertical synchronizing signal V is also input to the synchronizing signal transmission circuit 114.

  The synchronization signal transmission circuit 114 generates a second liquid crystal panel synchronization signal RG_SYNC using the vertical synchronization signal V and the R identification signal RID, and transmits the second liquid crystal panel synchronization signal RG_SYNC to the receiver 7. In this embodiment, the second liquid crystal panel synchronization signal RG_SYNC is transmitted. However, the first liquid crystal panel synchronization signal may be transmitted, or both may be transmitted.

FIG. 12 shows the receiver 7 of the liquid crystal shutter 1. FIG. 13 shows signal waveforms at various parts of the receiver 7.
As shown in FIGS. 12 and 13, the receiving circuit 211 demodulates the second liquid crystal panel synchronization signal RG_SYNC. The second liquid crystal panel synchronization signal RG_SYNC is input to the voltage controlled oscillator 212 as the phase synchronization signal a. The voltage controlled oscillator 212 includes a phase lock loop and a frequency divider, and generates and outputs a pulse signal b phase-synchronized with the second liquid crystal panel synchronization signal RG_SYNC. The pulse signal b is switched from the low level to the high level every frame period. The pulse signal b is input to the amplifier 213, shaped into positive and negative symmetric pulses around the reference potential, and input to the switch 215. Further, the pulse signal b is input to the ½ divider 214, and the ½ divider 214 outputs the switch control pulse signal c.

  When the switch control pulse c is positive, the switch 215 is connected to the terminal A, and when the switch control pulse c is negative, the switch 215 is connected to the terminal B. Terminal A is connected to amplifier 216 and amplifier 219, and terminal B is connected to amplifier 217 and amplifier 218. Amplifier 216 amplifies signal d from terminal A, and amplifier 217 amplifies signal e from terminal B. The signals amplified by the amplifier 216 and the amplifier 217 are combined and output to the output terminal 221 as the second liquid crystal panel drive signal h (normal voltage Vd). Here, the amplification factor of the amplifier 216 is set smaller than the amplification factor of the amplifier 217.

  On the other hand, the amplifier 219 amplifies the signal g (= d) from the terminal A, and the amplifier 218 amplifies the signal f (= e) from the terminal B. The signals amplified by the amplifier 219 and the amplifier 218 are combined and output to the output terminal 222 as the first liquid crystal panel drive signal i (normal voltage Vd). Here, the amplification factor of the amplifier 218 is set smaller than the amplification factor of the amplifier 219.

  The second liquid crystal panel 3R and the first liquid crystal panel 3L are driven by the second liquid crystal panel drive signal h and the first liquid crystal panel drive signal i, respectively. Note that j in FIG. 13 shows an opening / closing sequence of the first liquid crystal panel 3L (for the left eye) and the second liquid crystal panel 3R (for the right eye), and k is an image for the left eye displayed on the liquid crystal display device and The sequence of video for the right eye is shown.

  According to the image display system including the liquid crystal shutter 1 and the driving method of the liquid crystal shutter 1 according to the embodiment configured as described above, the image display system includes the glasses-mounted liquid crystal shutter 1 and the image for the left eye. A liquid crystal display device 2 that alternately displays (video) and right-eye images (video). The liquid crystal shutter 1 includes a first liquid crystal panel 3L in OCB mode for the left eye, a second liquid crystal panel 3R in OCB mode for the right eye, a power supply unit 6, a receiver 7, and a drive unit 5.

  The power supply unit 6 can output an initial voltage Va, a normal voltage Vd, and a voltage Vcom for initial transition of the liquid crystal molecules 30m from the splay alignment to the bend alignment. After the initial transition of the liquid crystal molecules 30m, the driving unit 5 applies the pulsed normal voltage Vd to each of the first liquid crystal panel 3L and the second liquid crystal panel 3R in association with the synchronization signal, and the liquid crystal molecules 30m bend. In the state in which the alignment is adopted, it is possible to perform normal driving in which the first liquid crystal panel 3L and the second liquid crystal panel 3R are alternately switched between a transmission state (ON) and a non-transmission state (OFF).

  The liquid crystal display device 2 alternately displays a left-eye image (video) and a right-eye image (video) at a frequency of 120 Hz, and the first liquid crystal panel 3L and the second liquid crystal panel 3R are transmissive at a frequency of 120 Hz ( Since the display is alternately switched between ON and non-transmission (OFF), a clear three-dimensional image equivalent to the case where an image is displayed at a frequency of substantially 60 Hz can be displayed to the user wearing the liquid crystal shutter 1.

  The driving unit 5 can switch the holding drive for applying the initial voltage Va to each of the first liquid crystal panel 3L and the second liquid crystal panel 3R from the normal driving, and can change the transmittance of the holding driving period to the normal driving period. It can be different from the transmittance.

  The user wearing the liquid crystal shutter 1 displays an image with a clearly different transmittance and color during the holding drive period as compared with the normal drive period (monochrome behavior). Can be clearly seen.

  The initial voltage Va used for the initial transition can be used in the holding drive period. Since it is not necessary to increase the number of voltages (power supplies) to be applied to the first liquid crystal panel 3L and the second liquid crystal panel 3R, it is possible to suppress an increase in manufacturing cost and, in turn, suppress an increase in product price. it can.

  Furthermore, when the time counted by the timer 9 reaches a specific time, the drive unit 5 can stop applying the initial voltage Va to the first liquid crystal panel 3L and the second liquid crystal panel 3R. Since the holding drive period can be switched to the drive stop period, power consumption can be suppressed. During the drive stop period, the first liquid crystal panel 3L and the second liquid crystal panel 3R are each in a splay alignment state, and the transmitted light is bluish compared to the operation period (holding drive period), so the user may be in the drive stop period. It can be perceived.

  As described above, the liquid crystal shutter 1 that can determine the state of the liquid crystal shutter 1 without adding a new component and can ensure the operational stability, the liquid crystal shutter driving method, and the liquid crystal shutter 1 are provided. An image display system can be obtained.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment.

  For example, the power supply unit 6 can output the voltage VIH (+20 V), which is the initial voltage Va, but may output a voltage VIL (−20 V) having a polarity opposite to that of the voltage VIH. In this case, the drive unit 5 can be held and driven with an alternating current using the initial voltage Va (voltage VIH) and the voltage VIL during the holding drive period. The frequency of the holding drive (holding voltage) is preferably made as small as possible as compared with the frequency of normal driving (120 Hz), and thus power consumption can be suppressed.

  The liquid crystal shutter 1 and the driving method of the liquid crystal shutter 1 may be configured such that when the user removes the liquid crystal shutter 1, the driving unit 5 switches from normal driving to holding driving. Note that whether or not the user has removed the liquid crystal shutter 1 can be easily detected by providing a sensor on the glasses frame 4 or the like.

  The drive unit 5 may switch from the holding drive to the regular driving, for example, when the user remounts the liquid crystal shutter 1 during the holding driving period. In addition, when the user does not reattach the liquid crystal shutter 1 for a specific time, the driving unit 5 may stop driving the first liquid crystal panel 3L and the second liquid crystal panel 3R.

  The voltage values such as the initial voltage Va, the normal voltage Vd, and the voltage Vcom are not limited to the above examples, and can be variously modified and adjusted to suit the design of the first liquid crystal panel 3L and the second liquid crystal panel 3R. It only has to be done.

  In the above embodiment, the liquid crystal display device 2 alternately displays the left-eye image (video) and the right-eye image (video) at a frequency of 120 Hz, and the first liquid crystal panel 3L and the second liquid crystal panel 3R are 120 Hz. However, these frequencies are not limited to 120 Hz and can be variously modified.

  The drive unit 5 is housed in the housing 8, but is not limited thereto, and can be variously modified. For example, a part or all of the drive unit 5 is provided in the first liquid crystal panel 3L and the second liquid crystal panel 3R. It may be.

  The liquid crystal shutter 1 is not limited to a glasses-mounted liquid crystal shutter, and can be variously modified. In this case, the liquid crystal shutter 1 may be attached to a member other than the glasses frame 4.

  The configuration and operation for the liquid crystal display device 2 to display the image for the left eye and the image for the right eye are not limited to the above-described embodiment, and can be variously modified. It is also possible to substitute with.

  The display device is not limited to the liquid crystal display device 2 and can be variously modified, and may be a display device such as a CRT (cathode-ray tube) display device or an organic EL display device.

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal shutter, 2 ... Liquid crystal display device, 3L ... 1st liquid crystal panel, 3R ... 2nd liquid crystal panel, 4 ... Glasses frame, 5 ... Drive part, 6 ... Power supply part, 7 ... Receiver, 8 ... Case, DESCRIPTION OF SYMBOLS 9 ... Timer 10, 20 ... Electrode substrate, 14, 24 ... Optical compensation film, 15, 25 ... Polarizing plate, 30 ... Liquid crystal layer, 30m ... Liquid crystal molecule, 50 ... Liquid crystal display panel, 60 ... Array substrate, 70 ... Opposite Substrate, 80 ... liquid crystal layer, 100 ... control unit, PX ... pixel, Va ... initial voltage, Vd ... regular voltage, Vcom, VBH, VBL, VIH, VIL ... voltage, T1, T2 ... transmittance.

Claims (7)

An OCB mode first liquid crystal panel having a pair of electrode substrates and a liquid crystal layer sandwiched between the electrode substrates, covering the field of view of the left eye, and capable of controlling the transmittance of light incident on the left eye;
An OCB mode second liquid crystal panel having a pair of electrode substrates and a liquid crystal layer sandwiched between the electrode substrates, covering the field of view of the right eye, and capable of controlling the transmittance of light incident on the right eye;
An initial voltage for initial transition of liquid crystal molecules in the respective liquid crystal layers of the first liquid crystal panel and the second liquid crystal panel from a splay alignment to a bend alignment, and a voltage level relatively set lower than the initial voltage; A power supply unit capable of outputting a pulse-like normal voltage for alternately switching between a transmissive state and a non-transmissive state in a state where the liquid crystal molecules adopt the bend alignment in each of the first liquid crystal panel and the second liquid crystal panel;
A receiver capable of receiving a synchronization signal;
The initial voltage is applied to each of the first liquid crystal panel and the second liquid crystal panel to perform the initial transition, and then the normal voltage is associated with the synchronization signal to each of the first liquid crystal panel and the second liquid crystal panel. A drive unit that performs normal drive to be applied to
When reception of the synchronization signal at the receiver is interrupted, the driving unit performs holding driving to apply the initial voltage to each of the first liquid crystal panel and the second liquid crystal panel. Shutter. A timer capable of counting a time when reception of the synchronization signal at the receiver is interrupted;
2. The drive unit according to claim 1, wherein when the time counted by the timer reaches a specific time, the driving unit stops applying the initial voltage to the first liquid crystal panel and the second liquid crystal panel. LCD shutter.   The liquid crystal shutter according to claim 1, wherein when the reception of the synchronization signal at the receiver is resumed, the driving unit resumes the normal driving associated with the synchronization signal.   The liquid crystal shutter according to claim 1, wherein the initial voltage when the driving unit performs the holding driving is a constant voltage.   The liquid crystal shutter according to claim 1, wherein each of the first liquid crystal panel and the second liquid crystal panel is a normally white type. An OCB mode first liquid crystal panel having a pair of electrode substrates and a liquid crystal layer sandwiched between the electrode substrates, covering the field of view of the left eye and controlling the transmittance of light incident on the left eye, and a pair of electrodes An OCB mode second liquid crystal panel having a liquid crystal layer sandwiched between the substrate and the electrode substrate, covering the field of view of the right eye, and capable of controlling the transmittance of light incident on the right eye, the first liquid crystal panel, An initial voltage for initial transition of liquid crystal molecules in each liquid crystal layer of the second liquid crystal panel from splay alignment to bend alignment, and a voltage level relatively shallower than the initial voltage are set, and the first liquid crystal panel and the second liquid crystal panel A power supply unit capable of outputting a normal pulse voltage for alternately switching between a transmissive state and a non-transmissive state with the liquid crystal molecules adopting the bend orientation of each liquid crystal panel, and receiving a synchronization signal A receiver, in the driving method of a liquid crystal shutter having a
The initial voltage is applied to each of the first liquid crystal panel and the second liquid crystal panel to perform the initial transition, and then the normal voltage is associated with the synchronization signal to each of the first liquid crystal panel and the second liquid crystal panel. The normal drive applied to the
A method for driving a liquid crystal shutter, comprising: holding driving for applying the initial voltage to each of the first liquid crystal panel and the second liquid crystal panel when reception of the synchronization signal at the receiver is interrupted. An OCB mode first liquid crystal panel having a pair of electrode substrates and a liquid crystal layer sandwiched between the electrode substrates, covering the field of view of the left eye and controlling the transmittance of light incident on the left eye, and a pair of electrodes An OCB mode second liquid crystal panel having a liquid crystal layer sandwiched between the substrate and the electrode substrate, covering the field of view of the right eye, and capable of controlling the transmittance of light incident on the right eye, the first liquid crystal panel, An initial voltage for initial transition of liquid crystal molecules in each liquid crystal layer of the second liquid crystal panel from splay alignment to bend alignment, and a voltage level relatively shallower than the initial voltage are set, and the first liquid crystal panel and the second liquid crystal panel A power supply unit capable of outputting a normal pulse voltage for alternately switching between a transmissive state and a non-transmissive state with the liquid crystal molecules adopting the bend orientation of each liquid crystal panel, and receiving a synchronization signal A receiver, and applying the initial voltage to each of the first liquid crystal panel and the second liquid crystal panel to perform the initial transition; then, associating the normal voltage with the synchronization signal, the first liquid crystal panel and the second liquid crystal panel A liquid crystal shutter comprising: a drive unit that performs normal driving to be applied to each of the liquid crystal panels;
A display device for displaying an image and transmitting the synchronization signal suitable for the image information to the liquid crystal shutter,
When receiving the synchronization signal at the receiver is interrupted, the driving unit performs holding driving to apply the initial voltage to each of the first liquid crystal panel and the second liquid crystal panel. Display system.

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