JP2012145778A - Liquid crystal display device, liquid crystal television device provided with the same, and drive method for liquid crystal display device - Google Patents

Abstract

A liquid crystal display device in which flickering of an image hardly occurs even when a backlight light source is intermittently turned on and off is realized.
One or more driven by a first compression lighting timing pattern in which the time axis of the lighting timing ((1)) pattern before switching is compressed to 1 / N (N is an integer of 2 or more). Frame period (Y1) and one or more frame periods (2) driven by a second compressed lighting timing pattern in which the time axis of the lighting timing ((2)) after switching is compressed to 1 / N. Y2) and the switching period (Y) consisting of M frame periods (M is an integer equal to or greater than N), the last frame period (X) by the lighting timing ((1)) before switching, and the switching period after switching It is provided between the start frame period (Y) based on the lighting timing ((2)).
[Selection] Figure 1

Description

  The present invention relates to a liquid crystal display device that intermittently lights a backlight.

  LEDs are widely used as display light sources for electric bulletin boards and traffic lights, and white LEDs are particularly widespread as display light sources such as backlights for mobile phones and digital cameras. When an LED is used as a backlight light source, it is necessary to adjust the brightness of the display to a certain luminance. For this reason, it is indispensable to control the LED drive current by using an LED driver IC rather than simply causing the LED to emit light.

The LED brightness adjustment method is generally a method of adjusting the LED drive current value as described above, but there is a pulse width modulation (PWM) method as a finer brightness adjustment method. Here, luminance adjustment by current value and luminance adjustment method by pulse width modulation will be described.
(Brightness adjustment by LED drive current value)
Adjustment by the LED drive current value is the simplest method for adjusting the luminance of the LED. Since most LED specifications have luminance-forward current characteristics, the relationship between luminance and forward current can be confirmed. However, the chromaticity of the LED also changes by changing the drive current value. Therefore, it should be noted that this method has a problem that the luminance can be controlled, but the emission color also changes.
(Brightness adjustment by pulse width modulation)
As a means for solving this problem, the above-described LED brightness adjustment method by pulse width modulation can be employed. In this case, the pulse width modulation adjusts the brightness of the LED by changing the current application time without changing the drive current value of the LED. That is, the effective time value of the LED is controlled by controlling the ON time.

FIG. 8 is an explanatory diagram of pulse width modulation. In the pulse width modulation, the luminance is adjusted by alternately repeating the state in which the drive current I _LED is flowing through the _LED and the state in which the _LED is not flowing at the cycle Tp. When the period Tp is long, lighting / turn-off appears to be repeated to the human eye, but flickering is not known to the human eye by shortening the period Tp (increasing the frequency), so such a short period If the time during which the drive current I _LED is supplied at Tp (ON time) ton and the time during which the drive current I _LED is not supplied (OFF time) toff are changed, the brightness appears to change. The time ton is referred to as a pulse width Wp, and the ratio of the pulse width Wp in the period Tp, that is, the ratio of the ON period is referred to as a duty ratio. If the ratio of the pulse width (ON time) Wp to the period Tp is 60%, the duty ratio is 60%. The brightness of the LED can be adjusted by changing the duty ratio. The larger the duty ratio, the brighter the LED.

  As a method for adjusting the luminance of the LED, there is a method in which current value adjustment and pulse width modulation are combined. It is important to use this method properly according to the application.

In the brightness adjustment method described so far, when the power supply voltage fluctuates (for example, when a battery such as a battery is driven), the brightness also changes. Further, the power supply voltage not emit light and becomes less forward voltage V _F the LED. Therefore, when used in an actual application, a constant current driving circuit using an LED driver IC is common. Many LED driver ICs have a boosting function and supply a voltage necessary for LED driving. In addition, since the constant current driving circuit can supply a constant current necessary for LED driving without depending on the power supply voltage, the LED can be turned on with peace of mind. Also no longer be affected by the variation of the forward voltage V _F.

  Generally, a control system for a backlight light source includes an LED driver that drives an LED of the backlight light source, and a backlight light source control unit that controls the entire backlight light source via the LED driver.

  FIG. 9 shows a configuration of a backlight light source control unit 200 that is an example of a backlight light source control unit. The backlight light source control unit 200 includes a main control unit I / F 200a, a one frame time control unit 200b, a delay time control unit 200c, a PWM control unit 200d, and an LED driver I / F 200e.

  As shown in FIG. 10, the backlight light source is controlled to be turned on / off during one frame period T in synchronization with the vertical synchronization signal VSYNC. However, this lighting / non-lighting lighting timing pattern (hereinafter simply referred to as lighting timing) is not always a constant timing, and for example, a 2D mode (two-dimensional video mode) of the television device by the user There are cases where the lighting timing of the backlight light source changes due to a switching operation with the 3D mode (3D video mode) or the like.

Therefore, the backlight source control unit 200 controls one frame time (length of one frame period) T by the one frame time control unit 200b and vertical synchronization by the delay time control unit 200c according to an instruction from the main control unit I / F 200a. Control of the delay time td from the timing of the signal VSYNC until the drive current I _LED is allowed to flow, and the control of the lighting time te where the drive current I _LED is allowed to flow by the PWM control unit 200d are performed. The determined one frame time T, delay time td, and lighting time te are instructed to the LED driver via the LED driver I / F 200e, whereby the lighting timing of the backlight light source is controlled.

  Below, the lighting timing of the backlight light source in the 2D mode and the 3D mode will be described as an example.

  FIG. 11 shows an example of lighting timing of the LED backlight light source in the 2D mode. In the liquid crystal display device in this example, the direct backlight light source is divided into LED regions L1 to L4 corresponding to the panel region divided into four equal parts in the vertical direction, and each LED region is sequentially scanned. It is configured so that it can be turned on and off. For example, in order to reduce the afterimage effect by bringing the hold-type display closer to the impulse-type display, the delay time td and the lighting time te described in FIG. 10 are increased in each LED region according to the average luminance level of the input video data. Is controlled (see, for example, Patent Document 1).

  In FIG. 11, as an example, each of the LED areas L1 to L4 is lit so that the display is performed in the latter half of one frame period in synchronization with the video updated based on the timing of the vertical synchronization signal VSYNC. The case is shown.

  Note that the lighting timing example in FIG. 11 is shown for convenience in this specification, and the intermittent lighting pattern in the 2D mode is not limited to this. Actually, the timing for reducing the optimum afterimage in the 2D mode differs depending on the system.

  Next, FIG. 12 shows an example of lighting timing of the LED backlight light source in the 3D mode. The LED regions L1 to L4 are sequentially scanned and turned on and off as in the case of FIG. The 3D mode in this case is driven by a frame sequential method, and displays the left-eye video (L) in the first half frame of one frame period and the right-eye video (R) in the second half frame. Video is displayed twice for each frame at double speed. In the 3D mode, the backlight light source is driven to light up in the second half frame in synchronization with the video written in the liquid crystal.

  Note that the lighting timing example of FIG. 12 is also shown for convenience in this specification, and the intermittent lighting pattern in the 3D mode is not limited to this. Actually, the optimum timing for reducing the L / R video crosstalk in the 3D mode differs depending on the system.

  As shown in the above example, the lighting timing of the backlight light source is generally different in lighting / extinguishing timing depending on the operation mode and purpose such as the 2D mode and the 3D mode.

Japanese Utility Model Gazette “Japanese Patent Laid-Open No. 2004-062134” (published on February 26, 2004) Japanese Patent Publication “Japanese Patent Laid-Open No. 2004-233932 (published on August 19, 2004)”

  However, in the above-described conventional liquid crystal display device, for example, the optimal lighting timing of the LED when the operation mode of the liquid crystal display device is switched such that the lighting timing of each LED is different between the 2D mode and the 3D mode. Changes before and after switching.

  With reference to FIG. 13 and FIG. 14, a problem when a change in the lighting timing of the LED occurs will be described. In the liquid crystal display device described here, it is possible to switch between the lighting timing in the 2D mode indicated by (1) in FIGS. 13 and 14 and the lighting timing in the 3D mode indicated by (2) in FIGS. Suppose that

  The lighting timing (1) is a mode in which one frame period is one vertical period T, and the lighting is performed at a timing of delay time T / 2 and lighting time T / 4 (duty ratio 25%) with reference to the vertical synchronization signal VSYNC. It is.

  Lighting timing (2) is a mode in which one frame period is defined as one vertical period T and lighting is performed at a timing of a delay time of 3T / 4 and a lighting time of T / 4 (duty ratio 25%) with reference to the vertical synchronization signal VSYNC. It is.

  As described above, the lighting timing in the 2D mode and the 3D mode is not limited to the lighting timings (1) and (2).

  Here, in the conventional liquid crystal display device, FIG. 13 shows the lighting timing (3) when switching from the lighting timing (1) to the lighting timing (2) is performed.

  If switching from lighting timing (1) to lighting timing (2) is performed by a user operation or the like, switching from a cycle that was lit at lighting timing (1) to a cycle that is lit at lighting timing (2) Is performed in successive frames. As a result, as indicated by change A, the turn-off time from the last turn-on by the turn-on timing (1) to the first turn-on by the turn-on timing (2) is periodic at each of the turn-on timings (1) and (2). It is longer than the turn-off time. Therefore, when switching from the lighting timing (1) to the lighting timing (2) occurs, this switching is recognized as flickering of the LED lighting to the human eye.

  FIG. 14 shows the lighting timing (3) when switching from the lighting timing (2) to the lighting timing (1) is performed, contrary to FIG. When switching from the lighting timing (2) to the lighting timing (1) occurs, unlike the case of switching from the lighting timing (1) to the lighting timing (2), as shown by the change B, the lighting timing (1) depends on the lighting timing (1). The turn-off time from the last turn-on to the first turn-on by the turn-on timing (2) is shorter than the periodic turn-off time at each of the turn-on timings (1) and (2). Therefore, when switching from the lighting timing (1) to the lighting timing (2) occurs, this switching is recognized as flickering of the LED lighting to the human eye.

  As described above, in the conventional liquid crystal display device in which the backlight light source is intermittently turned on, the regularity on the time axis of the duty ratio controlled by the pulse width modulation is momentarily broken when the timing of turning on / off the backlight light source is changed. Therefore, there was a problem that the image flickers. From the viewpoint of TV display quality, it is desirable to reduce such flicker.

  The present invention has been made in view of the above problems, and a liquid crystal display device in which image flickering hardly occurs even when the intermittent lighting timing of the backlight light source is switched, a liquid crystal television device including the same, and driving of the liquid crystal display device are provided. To realize the method.

In order to solve the above problems, the liquid crystal display device of the present invention
A backlight source and a backlight source controller that controls lighting timing of the backlight source, and the backlight source controller controls the lighting timing so that the backlight source intermittently lights within one frame period. A liquid crystal display device for performing
The backlight light source controller is
When it is instructed from outside the backlight source control unit that the lighting timing pattern of the video signal to be displayed is switched, the time axis of the lighting timing pattern before switching is set to 1 / N (N is 2 or more). One or more frame periods driven with a first compression lighting timing pattern compressed to an integer), and a second compression lighting timing in which the time axis of the lighting timing pattern after switching is compressed to 1 / N. A switching period composed of M (M is an integer equal to or greater than N) frame periods combined with one or more frame periods driven in the pattern of: a final frame period based on the lighting timing before switching; It is characterized by being provided during the start frame period according to the lighting timing.

  According to the above invention, the switching period is switched to a period shorter than one frame period before and after switching of the lighting timing, which is a frame period driven by the first compression lighting timing or the second compression lighting timing pattern. Lighting control is performed at the same duty ratio as before. Accordingly, even when different lighting timings are connected before and after switching, a smooth lighting pattern transition period due to the switching period is inserted between the lighting patterns according to the unique delay time and lighting time of each lighting timing. Therefore, it is possible to mitigate the perception of steep switching of the lighting pattern.

  As described above, there is an effect that it is possible to realize a liquid crystal display device in which image flickering hardly occurs even when the intermittent lighting timing of the backlight light source is switched.

In order to solve the above problems, the liquid crystal display device of the present invention
The first k frame periods (k is an integer less than or equal to 1 and less than N) in the switching period are driven with the first compression lighting timing pattern, and the remaining Nk frame periods in the switching period are It is characterized by being driven at the second compression lighting timing.

  According to said invention, there exists an effect that it becomes possible to transfer very smoothly from the lighting timing before switching to the lighting timing after switching.

In order to solve the above problems, the liquid crystal display device of the present invention
It is characterized by N = 2.

  According to the above invention, the switching period is the lighting timing in which the time axis before and after the switching is compressed by half. Therefore, the switching of the lighting timing according to the present invention is used for a liquid crystal display device with a general driving frequency. There is an effect that it can be applied.

In order to solve the above problems, the liquid crystal display device of the present invention
The backlight light source is a direct type backlight.

  According to the above invention, since the lighting region of the backlight light source can be divided into a plurality of parts in the vertical direction of the panel, it is advantageous in reducing the afterimage effect by bringing the hold type display closer to the impulse type display. Play.

In order to solve the above problems, the liquid crystal display device of the present invention
The backlight light source is a side illumination type backlight.

  According to the above invention, since the backlight light source only needs to be arranged on the edge side, there is an effect that the configuration is simplified.

In order to solve the above problems, the liquid crystal display device of the present invention
The lighting timing is switched between the lighting timing in the 2D video mode and the lighting timing in the 3D video mode.

  According to the above-described invention, there is an effect that flickering at the time of switching can be effectively suppressed in a typical video display in which the pattern of lighting timing is switched.

In order to solve the above problems, the liquid crystal display device of the present invention
The lighting timing is switched between the lighting timings in the 3D video mode.

  According to the above-described invention, there is an effect that flickering at the time of switching can be effectively suppressed in a typical video display in which the pattern of lighting timing is switched.

In order to solve the above problems, the liquid crystal television device of the present invention provides
The liquid crystal display device is provided, and video display is performed by the liquid crystal display device.

  According to the above-described invention, there is an effect that it is possible to realize a liquid crystal television apparatus in which video flickering hardly occurs even when the intermittent lighting timing of the backlight light source is switched.

In order to solve the above problems, a driving method of a liquid crystal display device of the present invention
A driving method of a liquid crystal display device for controlling a lighting timing of the backlight light source of a liquid crystal display device including a backlight light source so as to be intermittently lit within one frame period,
When switching the lighting timing pattern of the video signal to be displayed, the first compression lighting timing pattern in which the time axis of the lighting timing pattern before switching is compressed to 1 / N (N is an integer of 2 or more). And one or more frame periods driven by a second compressed lighting timing pattern obtained by compressing the time axis of the lighting timing pattern after switching to 1 / N. Is provided between the final frame period based on the lighting timing before switching and the start frame period based on the lighting timing after switching. It is characterized by.

  According to the above invention, the switching period is switched to a period shorter than one frame period before and after switching of the lighting timing, which is a frame period driven by the first compression lighting timing or the second compression lighting timing pattern. Lighting control is performed at the same duty ratio as before. Accordingly, even when different lighting timings are connected before and after switching, a smooth lighting pattern transition period due to the switching period is inserted between the lighting patterns according to the unique delay time and lighting time of each lighting timing. Therefore, it is possible to mitigate the perception of steep switching of the lighting pattern.

  As described above, there is an effect that it is possible to realize a driving method of a liquid crystal display device in which image flickering hardly occurs even when the intermittent lighting timing of the backlight light source is switched.

In order to solve the above problems, a driving method of a liquid crystal display device of the present invention
The first k frame periods (k is an integer greater than or equal to 1 and less than N) in the switching period are driven with the first compression lighting timing pattern, and the remaining Nk frame periods in the switching period are It is characterized by being driven at the second compression lighting timing.

  According to said invention, there exists an effect that it becomes possible to transfer very smoothly from the lighting timing before switching to the lighting timing after switching.

The liquid crystal display device of the present invention is as described above.
A backlight source and a backlight source controller that controls lighting timing of the backlight source, and the backlight source controller controls the lighting timing so that the backlight source intermittently lights within one frame period. A liquid crystal display device for performing
The backlight light source controller is
When it is instructed from outside the backlight source control unit that the lighting timing pattern of the video signal to be displayed is switched, the time axis of the lighting timing pattern before switching is set to 1 / N (N is 2 or more). One or more frame periods driven with a first compression lighting timing pattern compressed to an integer), and a second compression lighting timing in which the time axis of the lighting timing pattern after switching is compressed to 1 / N. A switching period composed of M (M is an integer equal to or greater than N) frame periods combined with one or more frame periods driven in the pattern of: a final frame period based on the lighting timing before switching; It is provided between the start frame period by the lighting timing.

  As described above, there is an effect that it is possible to realize a liquid crystal display device in which image flickering hardly occurs even when the backlight light source is switched intermittently.

FIG. 2, which illustrates the embodiment of the present invention, is a timing chart illustrating a first lighting timing of the liquid crystal display device according to the first example. FIG. 9 is a timing chart illustrating the second lighting timing of the liquid crystal display device according to the first example, according to the embodiment of the present invention. FIG. 9 is a timing chart illustrating the lighting timing of the liquid crystal display device according to the second example, illustrating the embodiment of the present invention. FIG. 9 is a timing chart illustrating the lighting timing of the liquid crystal display device according to the third example, illustrating the embodiment of the present invention. FIG. 9 is a timing chart illustrating the lighting timing of the liquid crystal display device according to the fourth example, illustrating an embodiment of the present invention. 1, showing an embodiment of the present invention, is a block diagram illustrating a configuration of a liquid crystal display device. FIG. It is a block diagram which shows the structure of the backlight light source control part with which the liquid crystal display device of FIG. 6 is provided. It is a wave form diagram of the signal which shows a prior art and illustrates pulse width modulation. It is a block diagram which shows a prior art and shows the structure of the backlight light source control part with which a liquid crystal display device is provided. FIG. 10 is a signal waveform diagram illustrating a method of controlling lighting timing by the backlight light source control unit of FIG. 9. It is a timing chart explaining the 1st lighting timing controlled by the backlight light source control part of FIG. It is a timing chart explaining the 2nd lighting timing controlled by the backlight light source control part of FIG. 10 is a timing chart for explaining switching of the lighting timing of the first pattern controlled by the backlight light source control unit of FIG. 9. 10 is a timing chart for explaining switching of lighting timing of the second pattern controlled by the backlight light source control unit of FIG. 9.

The embodiment of the present invention will be described with reference to FIGS. 1 to 7 as follows.
(System configuration of liquid crystal display device)
FIG. 1 shows a main part of the system configuration of the liquid crystal display device 10 according to the present embodiment.

  The liquid crystal display device 10 includes a main control unit 1, a backlight light source control unit 2, an LED driver 3, a backlight light source 4, a liquid crystal panel control unit 5, and a liquid crystal panel 6.

  The main control unit 1 includes a CPU (arithmetic unit), an EEPROM (nonvolatile memory), and the like, and comprehensively controls the liquid crystal display device 10 by executing various control programs.

  The LED driver 3 adjusts the power supplied to each LED of the backlight light source 4 according to a control command (for example, duty ratio) from the backlight light source control unit 2 to thereby determine whether or not each LED of the backlight light source 4 emits light. And adjust its strength.

  Hereinafter, in the LED driver 3, a signal generated for causing the backlight source 4 to emit light is referred to as an LED drive signal. The LED driving signal is, for example, a signal input to an FET or a transistor that switches whether power is supplied to the backlight light source 4. The LED driver 3 adjusts the power supplied to each LED of the backlight source 4 by performing pulse width modulation (PWM) control, which is an example of blinking control of the LED drive signal. In such PWM control, ON / OFF of the LED drive signal is switched at a predetermined control frequency, and the backlight light source 4 blinks.

  Here, the liquid crystal display device 10 is configured such that an LED drive signal is also input to the backlight light source control unit 2. As a result, the backlight source control unit 2 can detect the ON / OFF state of the LED drive signal, that is, the light emission / extinction timing of the backlight source 4.

  The backlight light source control unit 2 controls the presence / absence of light emission of each LED of the backlight light source 4 and its intensity by giving a control command to the LED driver 3. Here, in particular, control is performed so that the backlight light source is intermittently lit within one frame period by the PWM control or the like. Note that the backlight light source control unit 2 is embodied by, for example, an FPGA or an ASIC.

  In addition to the direct fluorescent lamp, the backlight light source 4 may be a direct light source or a side illumination type (edge light type) LED light source or EL light source. In particular, LEDs (light-emitting diodes) have a response speed of several tens to several hundreds of ns, and are more responsive than the millisecond order of fluorescent lamps. Is possible. In the direct type, as described in the background art, since the lighting area (LED area) of the backlight light source 4 can be divided into a plurality of parts in the vertical direction of the panel, the after-type effect is obtained by bringing the hold type display closer to the impulse type display. It is advantageous to reduce. In the side illumination type, since the backlight light source need only be arranged on the edge side, the configuration is simplified.

  The liquid crystal panel control unit 5 receives video data from the main control unit 1 and controls the display drive of the liquid crystal panel 6 based on a timing signal generated inside.

  Next, FIG. 2 shows a detailed block diagram of the backlight light source control unit 2.

  The backlight light source control unit 2 includes a main control unit I / F 2a, a lighting timing change detection unit 2b, a one frame time control unit 2c, a delay time control unit 2d, a PWM control unit 2e, and an LED driver I / F 2f. Yes.

  The main control unit I / F 2a interprets the lighting instruction signal of the backlight light source 4 transmitted from the main control unit 1a, and performs one frame period, delay time, and lighting time (duty) in the lighting control of the backlight light source 4. This is a block for performing extraction of the ratio.

  The lighting timing change detection unit 2b is a block that detects whether or not there is a change in the lighting control signal transmitted from the main control unit 1a outside the backlight light source control unit 2. The lighting control signal includes an instruction as to whether or not to switch a lighting timing pattern (hereinafter simply referred to as “lighting timing”) of a video signal to be displayed.

  The one-frame time control unit 2c is a block that controls one frame time (the length of one frame period) with respect to lighting of the backlight light source 4.

  The delay time control unit 2d is a block that controls the delay time from the timing of the vertical synchronization signal VSYNC to the timing at which lighting is started.

  The PWM control unit 2e is a block that controls the lighting time (duty ratio) in one frame period.

  The LED driver I / F 2f is for performing lighting control according to the LED driver to be used based on the lighting timing information determined by the one-frame time control unit 2c, the delay time control unit 2d, and the PWM control unit e. It is a block.

  The lighting timing change detection unit 2b monitors the one frame period, the delay time, and the lighting time (duty ratio) extracted by the main control unit I / F 2a, and the monitor value is changed between consecutive frames. The one frame time control unit 2c, the delay time control unit 2d, and the PWM control unit 2e are notified of the detection result.

  When each block of the 1-frame time control unit 2c, the delay time control unit 2d, and the PWM control unit 2e receives notification from the lighting timing change detection unit 2b that a change in lighting timing has been detected, as described later, The lighting control of the backlight light source 4 is performed by N-times speed driving (N is an integer of 2 or more) in the frame.

  Next, switching of the lighting timing of the backlight light source 4 in the present embodiment will be described with reference to examples.

  FIG. 1 and FIG. 2 show LED lighting timings when switching of LED lighting timings occurs in this embodiment. In the liquid crystal display device 10 described here, as shown in FIGS. 1 and 2, the lighting timing in the 2D mode (hereinafter referred to as lighting timing (1)) and the lighting timing in the 3D mode (hereinafter referred to as lighting timing ( It is assumed that switching to 2) is possible.

  With respect to the lighting timing (1), if one vertical period of display is T, the delay time until the lighting pulse P1 for determining the lighting period is T / 2 based on the timing of the vertical synchronization signal VSYNC, and the pulse of the lighting pulse P1 This is a mode in which the lighting time as a width is turned on at a timing of T / 4 (duty ratio 25%). Here, the illustrated lighting timing (1) is a lighting timing when driving at a normal frequency (for example, 60 Hz in Japan and 50 Hz in Europe), and one vertical period T is equal to one frame period.

  With respect to the lighting timing (2), if one vertical period of display is T, the delay time until the lighting pulse P2 for determining the lighting period is 3T / 4 based on the timing of the vertical synchronization signal VSYNC, and the pulse of the lighting pulse P2 This is a mode in which the lighting time as a width is turned on at a timing of T / 4 (duty ratio 25%). Here, the lighting timing (1) shown in the figure is the lighting timing when driving at a normal frequency, and one vertical period T is equal to one frame period.

  In the lighting timing (1) and the lighting timing (2), one frame period by normal frequency driving is equal to each other.

  In the present embodiment, the lighting timing (1) and the lighting timing (2) are defined as the above timing, but the lighting timing in the 2D mode and the 3D mode is not limited to the above lighting timing.

  FIG. 1 shows a lighting timing (3) which is a lighting pattern when switching from the lighting timing (1) by the normal frequency driving to the lighting timing (2) by the normal frequency driving is performed.

  In the liquid crystal display device 10 according to the present embodiment, the main control unit 1 instructs the backlight light source control unit 2 to switch the lighting timing, and the backlight light source control unit 2 causes the lighting timing change detection unit 2b to switch the lighting timing. When the instruction is detected, the last frame period (here, the final vertical period X) of the lighting timing (1) by the normal frequency driving before switching and the starting frame period of the lighting timing (2) by the normal frequency driving after switching. A switching period Y equal to the length of one frame period of the lighting pattern before and after switching is provided between (starting vertical period Z here). In the switching period Y, lighting control of the backlight light source 4 is performed by double speed driving (for example, 120 Hz in Japan and 100 Hz in Europe). The switching period Y is driven by being divided into two frame periods (switching frame periods) each having a length of T / 2. In the first frame period Y1, which is the first T / 2 period, lighting control is performed at the lighting timing based on the lighting timing (1). In the second frame period Y2, which is the second T / 2 period, lighting control is performed at the lighting timing based on the lighting timing (2).

  Specifically, the switching of the lighting timing is described. Before the lighting timing is switched, the lighting control is performed with the delay time T / 2 and the lighting time T / 4 (duty ratio 25%) by the lighting timing (1) of the normal frequency drive. Done.

  When a lighting timing switching instruction is detected by the lighting timing change detection unit 2b, the process shifts to a double speed drive switching period Y. In the first frame period Y1 of the switching period Y, the lighting control is performed at the lighting timing obtained by compressing the time axis of the lighting timing (1) by half. At this time, the delay time until the lighting pulse P3 for determining the lighting period is a delay time T / 4 that is a half of the delay time T / 2 of the lighting timing (1), and the lighting time of the lighting pulse P3 is the lighting timing (1 The lighting time T / 8 is ½ of the lighting time T / 4.

  In the second frame period Y2 of the switching period Y, the lighting control is performed at the lighting timing obtained by compressing the time axis of the lighting timing (2) by half. At this time, the delay time until the lighting pulse P4 for determining the lighting period is a delay time 3T / 8 which is a half of the delay time 3T / 4 of the lighting timing (2), and the lighting time of the lighting pulse P4 is the lighting timing (2 The lighting time T / 8 is ½ of the lighting time T / 4.

  When the switching period Y ends, lighting control is performed with a delay time 3T / 4 and a lighting time T / 4 (duty ratio 25%) according to the lighting timing (2) of normal frequency driving.

  The duty ratio of the lighting pulse P3 in the first frame period Y1 is 25%, which is equal to the duty ratio of the lighting pulse P1 at the lighting timing (1). The duty ratio of the lighting pulse P4 in the second frame period Y2 is 25%, which is equal to the duty ratio of the lighting pulse P2 at the lighting timing (2).

  Accordingly, the lighting control is performed at the same duty ratio as before the switching in the first frame period Y1 of the switching period Y, which is shorter than the one frame period before the switching of the lighting timing, and the second switching period Y is changed. Lighting control with the same duty ratio as after switching is performed in a period shorter than one frame period after switching of the lighting timing, which is the frame period Y2. Therefore, even if different lighting timings are connected before and after switching, a smooth lighting pattern transition period due to the switching period Y is inserted between the lighting patterns according to the unique delay time and lighting time of each lighting timing. Therefore, it is possible to mitigate the perception of sudden switching of the lighting pattern.

  Next, FIG. 2 shows a lighting timing (3) which is a lighting pattern when switching from the lighting timing (2) by the normal frequency driving to the lighting timing (1) by the normal frequency driving is performed.

  In the case of FIG. 2, as in FIG. 1, the last frame of the lighting timing (2) before switching (here, the final vertical period X) and the starting frame of lighting timing (1) after switching (here, the vertical start) Between the period Z), a switching period Y equal to the length of one frame period of the lighting pattern before and after switching is provided. In the switching period Y, the lighting control of the backlight light source 4 is performed by double speed driving. The switching period Y is driven by being divided into two frame periods (switching frame periods) each having a length of T / 2. In the first frame period Y1 corresponding to the first period T / 2 of the switching period Y, the lighting control is performed at the lighting timing based on the lighting timing (2), and the second period T / 2 corresponding to the second period T / 2 of the switching period Y is performed. In the second frame period Y2, the lighting control is performed at the lighting timing based on the lighting timing (1).

  Specifically, the switching of the lighting timing will be described. Before the lighting timing is switched, the lighting control is performed with the delay time 3T / 4 and the lighting time T / 4 (duty ratio 25%) by the lighting timing (2) of the normal frequency drive. Done.

  When a lighting timing switching instruction is detected by the lighting timing change detection unit 2b, the process shifts to a double speed drive switching period Y. In the first frame period Y1 of the switching period Y, the lighting control is performed at the lighting timing obtained by compressing the time axis of the lighting timing (2) by half. At this time, the delay time until the lighting pulse P4 for determining the lighting period is a delay time 3T / 8 which is a half of the delay time 3T / 4 of the lighting timing (2), and the lighting time of the lighting pulse P4 is the lighting timing (2 The lighting time T / 8 is ½ of the lighting time T / 4.

  In the second frame period Y2 of the switching period Y, the lighting control is performed at a lighting timing in which the time axis of the lighting timing (1) is compressed by half. At this time, the delay time until the lighting pulse P3 for determining the lighting period is a delay time T / 4 that is a half of the delay time T / 2 of the lighting timing (1), and the lighting time of the lighting pulse P3 is the lighting timing (1 The lighting time T / 8 is ½ of the lighting time T / 4.

  When the switching period Y ends, lighting control is performed with a delay time T / 2 and a lighting time T / 4 (duty ratio 25%) according to the lighting timing (1) of normal frequency driving.

  The duty ratio of the lighting pulse P4 in the first frame period Y1 is 25%, which is equal to the duty ratio of the lighting pulse P2 at the lighting timing (2). The duty ratio of the lighting pulse P3 in the second frame period Y2 is 25%, which is equal to the duty ratio of the lighting pulse P1 at the lighting timing (1).

  Accordingly, the lighting control is performed at the same duty ratio as before the switching in the first frame period Y1 of the switching period Y, which is shorter than the one frame period before the switching of the lighting timing, and the second switching period Y is changed. Lighting control with the same duty ratio as after switching is performed in a period shorter than one frame period after switching of the lighting timing, which is the frame period Y2. Therefore, even if different lighting timings are connected before and after switching, a smooth lighting pattern transition period due to the switching period Y is inserted between the lighting patterns according to the unique delay time and lighting time of each lighting timing. Therefore, it is possible to mitigate the perception of sudden switching of the lighting pattern.

  Note that the switching period Y generally includes a switching frame period of lighting timing (first compression lighting timing) in which the time axis of lighting timing before switching is compressed to 1 / N (N is an integer of 2 or more). It may be composed of M (M is an integer equal to or greater than N) switching frame periods with a switching frame period of lighting timing (second compressed lighting timing) obtained by compressing the time axis of the subsequent lighting timing to 1 / N. it can. At that time, at least one of the first compression lighting timing switching frame period and the second compression lighting timing switching frame period is included. In this embodiment, N = M = 2.

  The first k switching frame periods (k is an integer less than or equal to 1 and less than N) in the switching period Y are set to the first compression lighting timing, and the remaining N−k switching frame periods in the switching period Y are set to the second. It is preferable to set the compression lighting timing. In this case, it is possible to make a very smooth transition from the lighting timing before switching to the lighting timing after switching.

  FIG. 3 shows the lighting timing of the LED when the switching of the lighting timing of the LED occurs in this embodiment. In the liquid crystal display device 10 described here, as shown in FIG. 3, the lighting timing in the 2D mode (hereinafter referred to as lighting timing (1)) and the lighting timing in the 3D mode (hereinafter referred to as lighting timing (2)) )) Is possible.

  With respect to the lighting timing (1), if one vertical period of display is T, the delay time until the lighting pulse P1 for determining the lighting period is T / 2 based on the timing of the vertical synchronization signal VSYNC, and the pulse of the lighting pulse P1 This is a mode in which the lighting time as a width is turned on at a timing of T / 4 (duty ratio 25%). Here, the illustrated lighting timing (1) is a lighting timing when driving at a normal frequency (for example, 60 Hz in Japan and 50 Hz in Europe), and one vertical period is equal to one frame period.

  With respect to the lighting timing (2), if one vertical period of display is T, the delay time until the lighting pulse P2 for determining the lighting period is 3T / 4 based on the timing of the vertical synchronization signal VSYNC, and the pulse of the lighting pulse P2 This is a mode in which the lighting time as a width is turned on at a timing of T / 4 (duty ratio 25%). Here, the lighting timing (2) shown in the figure is the lighting timing when driving at a normal frequency, and one vertical period is equal to one frame period.

  In the lighting timing (1) and the lighting timing (2), one frame period by normal frequency driving is equal to each other.

  In the present embodiment, the lighting timing (1) and the lighting timing (2) are defined as the above timing, but the lighting timing in the 2D mode and the 3D mode is not limited to the above lighting timing.

  FIG. 3 shows a lighting timing (3) which is a lighting pattern when switching from the lighting timing (2) by double speed driving (for example, 120 Hz in Japan, 100 Hz in Europe) to the lighting timing (1) by double speed driving. Has been.

  The last frame of lighting timing (2) by double speed driving before switching (here, the second half frame period of final vertical period X) and the start frame of lighting timing (1) by double speed driving after switching (here, start vertical period Z) A switching period Y equal to twice the length of one frame period in the double speed drive is provided between the first half frame period). In the switching period Y, the lighting control of the backlight light source 4 is performed by quadruple speed driving (for example, 240 Hz in Japan and 200 Hz in Europe). The switching period Y is driven by being divided into four frame periods (switching frame periods) each having a length of T / 4. In the first frame period Y1 that is the first T / 4 period and the second frame period Y2 that is the second T / 4 period, the lighting control is performed at the lighting timing based on the lighting timing (2). Is called. In the third frame period Y3 that is the third T / 4 period and the fourth frame period Y4 that is the fourth T / 4 period, lighting control is performed at the lighting timing based on the lighting timing (1). Done.

  The switching of the lighting timing will be specifically described. Before the lighting timing is switched, the lighting control is performed by the lighting timing (2) of the double speed driving. In the lighting speed (2) of the double speed driving, the delay time until the lighting pulse P5 for determining the lighting period is 3T / 8 with reference to the timing obtained by dividing the timing of the vertical synchronization signal VSYNC by two in one vertical period T / 2. The lighting time of the lighting pulse P5 is T / 8 (duty ratio 25%). This is a lighting timing obtained by compressing the time axis of the lighting timing (2) by the normal frequency drive to one half.

  When a lighting timing change instruction is detected by the lighting timing change detection unit 2b, the operation shifts to a switching period Y for quadruple speed driving. In the first frame period Y1 and the second frame period Y2 of the switching period Y, the lighting control is performed at the lighting timing obtained by compressing the time axis of the lighting timing (2) by the normal frequency drive to ¼. At this time, the delay time until the lighting pulse P7 for determining the lighting period is a delay time 3T / 8 which is a quarter of the delay time 3T / 4 of the lighting timing (2) by the normal frequency drive, and the lighting time of the lighting pulse P7 is The lighting time T / 16 is ¼ of the lighting time T / 4 of the lighting timing (2) by the normal frequency drive.

  In the third frame period Y3 and the fourth frame period Y4 of the switching period Y, the lighting control is performed at the lighting timing obtained by compressing the time axis of the lighting timing (1) by the normal frequency drive to ¼. At this time, the delay time until the lighting pulse P8 for determining the lighting period is a delay time T / 8 that is a quarter of the delay time T / 2 of the lighting timing (1) by the normal frequency driving, and the lighting time of the lighting pulse P8 is The lighting time T / 16 is ¼ of the lighting time T / 4 of the lighting timing (1) by the normal frequency drive.

  When the switching period Y ends, lighting control is performed according to the lighting timing (1) of double speed driving. In the lighting speed (1) of the double speed driving, the delay time until the lighting pulse P6 for determining the lighting period is 3T / 8 based on the timing obtained by dividing the timing of the vertical synchronization signal VSYNC by two in one vertical period T / 2. The lighting time of the lighting pulse P6 is T / 8 (duty ratio 25%). This is a lighting timing obtained by compressing the time axis of the lighting timing (1) by the normal frequency drive to one half.

  The duty ratio of the lighting pulse P7 in the first frame period Y1 and the second frame period Y2 is 25%, which is equal to the duty ratio of the lighting pulse P5 at the lighting timing (2) by the double speed driving. The duty ratio of the lighting pulse P8 in the third frame period Y3 and the fourth frame period Y4 is 25%, which is equal to the duty ratio of the lighting pulse P6 at the lighting timing (1) by the double speed driving.

  Accordingly, the lighting control is performed at the same duty ratio as before the switching in a period shorter than the one frame period before the switching of the lighting timing of the first frame period Y1 and the second frame period Y2 of the switching period Y. During the switching period Y, the lighting control with the same duty ratio as that after the switching is performed in the third frame period Y3 and the fourth frame period Y4 that are shorter than one frame period after the switching of the lighting timing.

  Therefore, even if different lighting timings are connected before and after switching, a smooth lighting pattern transition period due to the switching period Y is inserted between the lighting patterns according to the unique delay time and lighting time of each lighting timing. Therefore, it is possible to mitigate the perception of sudden switching of the lighting pattern.

  In this embodiment, since double speed driving is performed before and after switching, flickering is hardly perceived even if switching directly from lighting timing (1) to lighting timing (2), but by introducing lighting timing (3). In addition, flicker is less likely to be perceived.

  Note that the switching period Y generally includes a switching frame period of lighting timing (first compression lighting timing) in which the time axis of lighting timing before switching is compressed to 1 / N (N is an integer of 2 or more). It may be composed of M (M is an integer equal to or greater than N) switching frame periods with a switching frame period of lighting timing (second compressed lighting timing) obtained by compressing the time axis of the subsequent lighting timing to 1 / N. it can. At that time, at least one of the first compression lighting timing switching frame period and the second compression lighting timing switching frame period is included. In this embodiment, N = 2 and M = 4.

  The first k switching frame periods (k is an integer less than or equal to 1 and less than N) in the switching period Y are set to the first compression lighting timing, and the remaining N−k switching frame periods in the switching period Y are set to the second. It is preferable to set the compression lighting timing. In this case, it is possible to make a very smooth transition from the lighting timing before switching to the lighting timing after switching.

  FIG. 4 shows the LED lighting timing when switching of the LED lighting timing occurs in this embodiment. In the liquid crystal display device 10 described here, as shown in FIG. 4, the lighting timing in the 2D mode (hereinafter referred to as lighting timing (1)) and the lighting timing in the 3D mode (hereinafter referred to as lighting timing (2)) )) Is possible.

  With respect to the lighting timing (1), if one vertical period of display is T, the delay time until the lighting pulse P1 for determining the lighting period is T / 2 based on the timing of the vertical synchronization signal VSYNC, and the pulse of the lighting pulse P1 This is a mode in which the lighting time as a width is turned on at a timing of T / 4 (duty ratio 25%). Here, the illustrated lighting timing (1) is a lighting timing when driving at a normal frequency (for example, 60 Hz in Japan and 50 Hz in Europe), and one vertical period T is equal to one frame period.

  With respect to the lighting timing (2), if one vertical period of display is T, the delay time until the lighting pulse P2 for determining the lighting period is 3T / 4 based on the timing of the vertical synchronization signal VSYNC, and the pulse of the lighting pulse P2 This is a mode in which the lighting time as a width is turned on at a timing of T / 4 (duty ratio 25%). Here, the lighting timing (2) shown in the figure is the lighting timing when driving at a normal frequency, and one vertical period T is equal to one frame period.

  In the lighting timing (1) and the lighting timing (2), one frame by normal frequency driving is equal to each other.

  In the present embodiment, the lighting timing (1) and the lighting timing (2) are defined as the above timing, but the lighting timing in the 2D mode and the 3D mode is not limited to the above lighting timing.

  FIG. 4 shows a lighting timing (3) that is a lighting pattern when switching from the lighting timing (2) by the normal frequency driving to the lighting timing (1) by the normal frequency driving is performed.

  The last frame (here, the final vertical period X) of the lighting timing (2) by the normal frequency drive before switching and the start frame (here, the starting vertical period Z) of the lighting timing (1) by the normal frequency driving after switching. Between them, a switching period Y equal to the length of one frame period in normal frequency driving is provided. In the switching period Y, the lighting control of the backlight source 4 is performed by quadruple speed driving (for example, 240 Hz in Japan and 200 Hz in Europe). The switching period Y is driven by being divided into four frame periods (switching frame periods) each having a length of T / 4. In the first frame period Y1 that is the first T / 4 period and the second frame period Y2 that is the second T / 4 period, the lighting control is performed at the lighting timing based on the lighting timing (2). Is called. In the third frame period Y3 that is the third T / 4 period and the fourth frame period Y4 that is the fourth T / 4 period, lighting control is performed at the lighting timing based on the lighting timing (1). Done.

  Illustrating the switching of the lighting timing, the lighting control is performed by the lighting timing (2) of the normal frequency drive before the switching of the lighting timing.

  When a lighting timing change instruction is detected by the lighting timing change detection unit 2b, the operation shifts to a switching period Y for quadruple speed driving. In the first frame period Y1 and the second frame period Y2 of the switching period Y, the lighting control is performed at the lighting timing obtained by compressing the time axis of the lighting timing (2) by the normal frequency drive to ¼. At this time, the delay time until the lighting pulse P7 for determining the lighting period is a delay time 3T / 8 which is a quarter of the delay time 3T / 4 of the lighting timing (2) by the normal frequency drive, and the lighting time of the lighting pulse P7 is The lighting time T / 16 is ¼ of the lighting time T / 4 of the lighting timing (2) by the normal frequency drive.

  In the third frame period Y3 and the fourth frame period Y4 of the switching period Y, the lighting control is performed at the lighting timing obtained by compressing the time axis of the lighting timing (1) by the normal frequency drive to ¼. At this time, the delay time until the lighting pulse P8 for determining the lighting period is a delay time T / 8 that is a quarter of the delay time T / 2 of the lighting timing (1) by the normal frequency driving, and the lighting time of the lighting pulse P8 is The lighting time T / 16 is ¼ of the lighting time T / 4 of the lighting timing (1) by the normal frequency drive.

  When the switching period Y ends, lighting control is performed according to the lighting timing (1) of normal frequency driving.

  The duty ratio of the lighting pulse P7 in the first frame period Y1 and the second frame period Y2 is 25%, which is equal to the duty ratio of the lighting pulse P5 at the lighting timing (2) by the double speed driving. The duty ratio of the lighting pulse P8 in the third frame period Y3 and the fourth frame period Y4 is 25%, which is equal to the duty ratio of the lighting pulse P6 at the lighting timing (1) by the double speed driving.

  Accordingly, the lighting control is performed at the same duty ratio as before the switching in a period shorter than the one frame period before the switching of the lighting timing of the first frame period Y1 and the second frame period Y2 of the switching period Y. During the switching period Y, the lighting control with the same duty ratio as that after the switching is performed in the third frame period Y3 and the fourth frame period Y4 that are shorter than one frame period after the switching of the lighting timing. Therefore, even if different lighting timings are connected before and after switching, a smooth lighting pattern transition period due to the switching period Y is inserted between the lighting patterns according to the unique delay time and lighting time of each lighting timing. Therefore, it is possible to mitigate the perception of sudden switching of the lighting pattern.

  Note that the switching period Y generally includes a switching frame period of lighting timing (first compression lighting timing) in which the time axis of lighting timing before switching is compressed to 1 / N (N is an integer of 2 or more). It may be composed of M (M is an integer equal to or greater than N) switching frame periods with a switching frame period of lighting timing (second compressed lighting timing) obtained by compressing the time axis of the subsequent lighting timing to 1 / N. it can. At that time, at least one of the first compression lighting timing switching frame period and the second compression lighting timing switching frame period is included. In this embodiment, N = M = 4.

  The first k switching frame periods (k is an integer less than or equal to 1 and less than N) in the switching period Y are set to the first compression lighting timing, and the remaining N−k switching frame periods in the switching period Y are set to the second. It is preferable to set the compression lighting timing. In this case, it is possible to make a very smooth transition from the lighting timing before switching to the lighting timing after switching.

  FIG. 5 shows the lighting timing of the LED when the switching of the lighting timing of the LED occurs in this embodiment. In the liquid crystal display device 10 described here, as shown in FIG. 5, the lighting timing in the first 3D mode (hereinafter referred to as lighting timing (1)) and the lighting timing in the second 3D mode (hereinafter referred to as “lighting timing (1)”). It is assumed that switching to the lighting timing (2) is possible.

  With respect to the lighting timing (1), assuming that one vertical period of display is T, the delay time to the lighting pulse P9 for determining the lighting period is 0 with the pulse width of the lighting pulse P9 based on the timing of the vertical synchronization signal VSYNC. In this mode, the lighting is performed at a timing of a certain lighting time T / 4 (duty ratio 25%). Here, the illustrated lighting timing (1) is a lighting timing when driving at a normal frequency (for example, 60 Hz in Japan and 50 Hz in Europe), and one vertical period T is equal to one frame period.

  With respect to the lighting timing (2), if one vertical period of display is T, the delay time until the lighting pulse P10 for determining the lighting period is 3T / 4 with reference to the timing of the vertical synchronization signal VSYNC, and the pulse of the lighting pulse P10 This is a mode in which the lighting time as a width is turned on at a timing of T / 4 (duty ratio 25%). Here, the lighting timing (2) shown in the figure is the lighting timing when driving at a normal frequency, and one vertical period T is equal to one frame period.

  In the lighting timing (1) and the lighting timing (2), one frame period by normal frequency driving is equal to each other.

  In this embodiment, the lighting timing (1) and the lighting timing (2) are defined as the above timing, but the lighting timing in the 3D mode is not limited to the above lighting timing.

  In FIG. 5, the lighting timing (3) is shown as a comparative example. In the lighting timing (3), switching from the lighting timing (1) by the normal frequency driving to the lighting timing (2) by the normal frequency driving is performed without inserting a changeover frame in between. As a result, the sum period t1 of the extinguishing period in the last frame of the lighting timing (1) by the normal frequency drive before switching and the extinguishing period in the start frame of the lighting timing (2) by the normal frequency driving after switching is normal. It becomes longer than one frame period (one vertical period T) of frequency driving. In this manner, at the lighting timing (3), a lighting pattern that particularly increases the interval between lighting / extinguishing at the time of switching appears, so that flicker is particularly easily recognized by human eyes.

  On the other hand, in the lighting timing (4) shown in FIG. 5 as the lighting timing of this embodiment, the last frame (here, the final vertical period X) of the lighting timing (1) by the normal frequency drive before switching and the normal after switching. A switching period Y equal to the length of one frame period in the normal frequency drive is provided between the start frame (here, the start vertical period Z) of the lighting timing (2) by frequency drive. In the switching period Y, lighting control of the backlight light source 4 is performed by double speed driving (for example, 120 Hz in Japan and 100 Hz in Europe). The switching period Y is driven by being divided into two frame periods (switching frame periods) each having a length of T / 2. In the first frame period Y1, which is the first T / 2 period, lighting control is performed at the lighting timing based on the lighting timing (1). In the second frame period Y2, which is the second T / 2 period, lighting control is performed at the lighting timing based on the lighting timing (2).

  Illustrating the switching of the lighting timing, the lighting control is performed at the lighting timing (1) of the normal frequency drive before the lighting timing is switched.

  When a lighting timing switching instruction is detected by the lighting timing change detection unit 2b, the process shifts to a double speed drive switching period Y. In the first frame period Y1 of the switching period Y, the lighting control is performed at the lighting timing obtained by compressing the time axis of the lighting timing (1) by the normal frequency drive to one half. At this time, the delay time until the lighting pulse P11 for determining the lighting period is a delay time 0 that is a half of the delay time 0 of the lighting timing (1) by the normal frequency driving, and the lighting time of the lighting pulse P9 is by the normal frequency driving. The lighting time T / 8 is one half of the lighting time T / 4 at the lighting timing (1).

  In the second frame period Y2 of the switching period Y, the lighting control is performed at the lighting timing obtained by compressing the time axis of the lighting timing (2) by the normal frequency drive to one half. At this time, the delay time until the lighting pulse P12 for determining the lighting period is a delay time 3T / 8 which is a half of the delay time 3T / 4 of the lighting timing (2) by the normal frequency driving, and the lighting time of the lighting pulse P12 is The lighting time T / 8 is one half of the lighting time T / 4 of the lighting timing (2) by the normal frequency drive.

  When the switching period Y ends, lighting control is performed according to the lighting timing (2) of normal frequency driving.

  The duty ratio of the lighting pulse P11 in the first frame period Y1 is 25%, which is equal to the duty ratio of the lighting pulse P9 at the lighting timing (1) by the normal frequency drive. The duty ratio of the lighting pulse P12 in the second frame period Y2 is 25%, which is equal to the duty ratio of the lighting pulse P10 at the lighting timing (2) by the normal frequency drive.

  Accordingly, the lighting control is performed at the same duty ratio as before the switching in the first frame period Y1 of the switching period Y, which is shorter than the one frame period before the switching of the lighting timing, and the second switching period Y is changed. Lighting control with the same duty ratio as after switching is performed in a period shorter than one frame period after switching of the lighting timing, which is the frame period Y2. In the case of FIG. 5, the extinguishing period t3 between the lighting pulse P11 and the lighting pulse P12 in the switching period Y is shorter than one frame period before and after switching, and the extinguishing period t2 in the final frame before switching and after switching. Since the length is close to the extinguishing period t4 in the start frame, the flicker as in the lighting pattern (3) is not perceived.

  Therefore, even if different lighting timings are connected before and after switching, a smooth lighting pattern transition period due to the switching period Y is inserted between the lighting patterns according to the unique delay time and lighting time of each lighting timing. Therefore, it is possible to mitigate the perception of sudden switching of the lighting pattern.

  Note that the switching period Y generally includes a switching frame period of lighting timing (first compression lighting timing) in which the time axis of lighting timing before switching is compressed to 1 / N (N is an integer of 2 or more). It may be composed of M (M is an integer equal to or greater than N) switching frame periods with a switching frame period of lighting timing (second compressed lighting timing) obtained by compressing the time axis of the subsequent lighting timing to 1 / N. it can. At that time, at least one of the first compression lighting timing switching frame period and the second compression lighting timing switching frame period is included. In this embodiment, N = M = 2.

  The first k switching frame periods (k is an integer less than or equal to 1 and less than N) in the switching period Y are set to the first compression lighting timing, and the remaining N−k switching frame periods in the switching period Y are set to the second. It is preferable to set the compression lighting timing. In this case, it is possible to make a very smooth transition from the lighting timing before switching to the lighting timing after switching.

  The embodiments have been described above.

  The liquid crystal display device of the present invention is provided with a switching period Y that performs lighting control of the backlight light source at N-times speed before and after switching when switching of lighting / extinguishing timing occurs. In the switching period Y, lighting before switching is performed. Based on the timing and lighting timing after switching, lighting control of the backlight light source is performed by compressing the lighting cycle by 1 / N times.

  As a result, the liquid crystal display device according to the present invention can reduce flickering at the time of mode switching such as 2D mode → 3D mode, 3D mode → 2D mode, 3D mode → 3D mode, etc. A liquid crystal display device with improved display quality can be realized. If switching of this embodiment is performed in such mode switching, flickering at the time of switching can be effectively suppressed in a typical video display in which the pattern of lighting timing is switched.

  In the embodiment of the present invention, only the case where the control of the present invention is applied to the switching of the lighting timing in the 2D mode → 3D mode, 3D mode → 2D mode has been described. → 3D mode, 3D mode → 2D mode is not limited to switching of the lighting timing, but can be applied to all cases where the lighting timing of the backlight light source is switched by other user operations.

  The present invention is not limited to the above-described embodiments, and those obtained by appropriately modifying the above-described embodiments based on common general technical knowledge and combinations thereof are also included in the embodiments of the present invention.

  The present invention can be suitably used for a general liquid crystal display device, particularly a liquid crystal display device used for a liquid crystal television device for displaying a moving image.

2 Backlight light source control unit 4 Backlight light source 10 Liquid crystal display device Y Switching period Y1 First frame period (frame period (switching period))
Y2 second frame period (frame period (of switching period))
Y3 3rd frame period (frame period (of switching period))
Y4 4th frame period (frame period (of switching period))

Claims (10)

A backlight source and a backlight source controller that controls lighting timing of the backlight source, and the backlight source controller controls the lighting timing so that the backlight source intermittently lights within one frame period. A liquid crystal display device for performing
The backlight light source controller is
When it is instructed from outside the backlight source control unit that the lighting timing pattern of the video signal to be displayed is switched, the time axis of the lighting timing pattern before switching is set to 1 / N (N is 2 or more). One or more frame periods driven with a first compression lighting timing pattern compressed to an integer), and a second compression lighting timing in which the time axis of the lighting timing pattern after switching is compressed to 1 / N. A switching period composed of M (M is an integer equal to or greater than N) frame periods combined with one or more frame periods driven in the pattern of: a final frame period based on the lighting timing before switching; A liquid crystal display device provided between the start frame period and the lighting timing.   The first k frame periods (k is an integer less than or equal to 1 and less than N) in the switching period are driven with the first compression lighting timing pattern, and the remaining Nk frame periods in the switching period are The liquid crystal display device according to claim 1, wherein the liquid crystal display device is driven at a second compression lighting timing.   3. The liquid crystal display device according to claim 1, wherein N = 2.   4. The liquid crystal display device according to claim 1, wherein the backlight light source is a direct type backlight.   4. The liquid crystal display device according to claim 1, wherein the backlight light source is a side illumination type backlight.   The switching of the lighting timing is switching between the lighting timing in the 2D video mode and the lighting timing in the 3D video mode. Liquid crystal display device.   6. The liquid crystal display device according to claim 1, wherein the lighting timing is switched between the lighting timings in a three-dimensional video mode.   A liquid crystal television device comprising the liquid crystal display device according to claim 1, wherein the liquid crystal display device displays an image. A driving method of a liquid crystal display device for controlling a lighting timing of the backlight light source of a liquid crystal display device including a backlight light source so as to be intermittently lit within one frame period,
When switching the lighting timing pattern of the video signal to be displayed, the first compression lighting timing pattern in which the time axis of the lighting timing pattern before switching is compressed to 1 / N (N is an integer of 2 or more). And one or more frame periods driven by a second compressed lighting timing pattern obtained by compressing the time axis of the lighting timing pattern after switching to 1 / N. Is provided between the final frame period based on the lighting timing before switching and the start frame period based on the lighting timing after switching. A method for driving a liquid crystal display device. The first k frame periods (k is an integer greater than or equal to 1 and less than N) in the switching period are driven with the first compression lighting timing pattern, and the remaining Nk frame periods in the switching period are The driving method of the liquid crystal display device according to claim 9, wherein the driving is performed at a second compression lighting timing.

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