KR101720338B1 - Stereoscopic Image Display Device and Driving Method the same - Google Patents

Abstract

An embodiment of the present invention relates to a stereoscopic image display panel, A backlight unit for providing light to the stereoscopic image display panel; A timing controller for supplying a left eye image and a right eye image to the stereoscopic image display panel; And a dimming control unit for controlling the backlight unit to distinguish the driving of the stereoscopic image display panel in the two-dimensional image mode and the driving of the three-dimensional image mode, thereby varying the local dimming of the backlight unit.

Description

TECHNICAL FIELD [0001] The present invention relates to a stereoscopic image display device and a driving method thereof,

An embodiment of the present invention relates to a stereoscopic image display apparatus and a driving method thereof.

The stereoscopic image display device is divided into a stereoscopic technique and an autostereoscopic technique.

The binocular parallax method uses the parallax images of the left and right eyes with large stereoscopic effects. In the binocular parallax system, there are a glasses system and a non-glasses system, and both systems are now practically used. The glasses system displays stereoscopic images by changing the polarization directions of the right and left parallax images on a direct-viewing stereoscopic image display panel or a projector, and realizes a stereoscopic image using polarized glasses or liquid crystal shutter glasses. In the non-eyeglass system, an optical plate such as a parallax barrier for separating the optical axis of the left and right parallax images is installed in front of or behind the stereoscopic image display panel.

In recent years, a stereoscopic image display device has been widely used as an organic light emitting display (OLED), a liquid crystal display (LCD), and a plasma display panel (PDP) And the like. Among them, a method of global dimming and local dimming of a backlight unit is used in order to reduce power consumption while improving image contrast in a screen.

In the three-dimensional image mode, the image signal is inputted to the left eye image and the right eye image alternately for each frame. When the local dimming is performed, the backlight unit modulates every frame. Accordingly, the viewer recognizes the left eye image and the right eye image as one image, but since the backlight unit is modulated every frame, crosstalk is caused to the three-dimensional image by the flashing phenomenon. In other words, when the three-dimensional image is displayed on the stereoscopic image display apparatus, the human eye recognizes one three-dimensional image in which the left and right images are combined in one frame period, while the backlight unit is modulated twice by local dimming. Therefore, a stereoscopic image display apparatus implemented with a conventional stereoscopic image display panel is required to improve crosstalk caused by local dimming.

According to an aspect of the present invention, there is provided a stereoscopic image display device including a stereoscopic image display device capable of reducing crosstalk occurring during local dimming and reducing halos and flashing phenomenon, A video display device and a driving method thereof are provided.

According to an embodiment of the present invention, there is provided a stereoscopic image display apparatus comprising: a stereoscopic image display panel; A backlight unit for providing light to the stereoscopic image display panel; A timing controller for supplying a left eye image and a right eye image to the stereoscopic image display panel; And a dimming control unit for controlling the backlight unit to distinguish the driving of the stereoscopic image display panel in the two-dimensional image mode and the driving of the three-dimensional image mode, thereby varying the local dimming of the backlight unit.

The dimming control unit may control the backlight unit to maintain the same local dimming state during the frame in which the first left eye image and the first right eye image are displayed on the stereoscopic image display panel.

The backlight unit may exhibit the same luminance during a frame in which the first left eye image and the first right eye image are displayed on the stereoscopic image display panel.

The backlight unit may exhibit the same luminance for two frames in which the first left eye image and the first right eye image are displayed on the stereoscopic image display panel.

The dimming control unit can control the backlight unit to perform local dimming at least once every two frames.

When the first left eye image is supplied, the timing control unit holds the first left eye image until the first right eye image is supplied. When the first right eye image is supplied to the timing controller, the timing control unit performs image compensation to obtain the compensated first left eye image, So that the compensated first right eye image can be generated.

The time at which the compensated first left eye image and the compensated first right eye image are displayed on the stereoscopic image display panel may be delayed by at least one frame from the timing at which the first left eye image and the first right eye image are supplied to the timing controller.

According to another aspect of the present invention, there is provided a method of controlling a stereoscopic image, comprising: holding a first left eye image until a first right eye image is supplied when a first left eye image is supplied to a timing controller; Performing image compensation on a first left eye image and a first right eye image to be supplied to the stereoscopic image display panel when the first right eye image is supplied to the timing control unit; And controlling the backlight unit so as to maintain the same local dimming state during a frame in which the first left eye image and the first right eye image are displayed while performing local dimming of the backlight unit together with image compensation, ≪ / RTI >

The step of controlling the backlight unit may control the backlight unit to display the same brightness during a frame in which the first left eye image and the first right eye image are displayed on the stereoscopic image display panel.

The backlight unit may exhibit the same luminance for two frames in which the first left eye image and the first right eye image are displayed on the stereoscopic image display panel.

The embodiment of the present invention controls the backlight unit so that the local dimming is performed at least once every two frames, thereby improving the crosstalk occurring in the local dimming in the stereoscopic image display apparatus, as well as halos and flashing phenomenon There is an effect of providing a stereoscopic image display apparatus and a driving method thereof that can be reduced.

1 is a schematic view of a stereoscopic image display apparatus according to an embodiment of the present invention;
FIG. 2 is a block diagram of a subpixel of the stereoscopic image display panel shown in FIG. 1. FIG.
3 is a diagram for explaining a driving concept of a stereoscopic image display apparatus.
4 is a schematic view for explaining a local dimming method of a stereoscopic image display apparatus according to an embodiment of the present invention.
FIG. 5 is a flowchart illustrating a local dimming method for a three-dimensional image of a stereoscopic image display apparatus according to an exemplary embodiment of the present invention. Referring to FIG.
FIG. 6 is a view for explaining frame-by-frame operation by the local dimming method of FIG. 5;
FIGS. 7 and 8 are diagrams for explaining a comparison between a local dimming method according to a comparative example and a local dimming method according to an embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram of a stereoscopic image display apparatus according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a subpixel of the stereoscopic image display panel shown in FIG. 1, Fig.

1, the stereoscopic image display apparatus according to an exemplary embodiment of the present invention includes an image supply unit 110, a timing controller 120, a driver 130, a dimming controller 140, a backlight unit (BLU) A stereoscopic image display panel PNL and stereoscopic glasses GLS.

The stereoscopic image display panel PNL includes a liquid crystal panel (LCD) for displaying an image and a control panel (ARP) for separating the image displayed on the liquid crystal panel (LCD) into a left eye image and a right eye image. The stereoscopic image display panel PNL receives a gate signal and a data signal from the driving unit 130, and displays a two-dimensional image or a three-dimensional image corresponding thereto. The control panel ARP included in the stereoscopic image display panel PNL includes an active retarder panel controlled by the timing controller 120 and separating the image displayed on the liquid crystal panel LCD into a left eye image and a right eye image, And the like. However, when the stereoscopic glasses GLS are constituted by the liquid crystal shutter system, the control panel ARP is omitted. That is, the control panel ARP may be included in the stereoscopic image display panel PNL or may be omitted depending on the method of implementing the stereoscopic image. The liquid crystal panel (LCD) included in the stereoscopic image display panel PNL includes a TFT substrate on which a thin film transistor (hereinafter referred to as "TFT"), a capacitor and the like are formed, a color filter substrate on which a color filter, . A liquid crystal layer is formed between the TFT substrate of the liquid crystal panel (LCD) and the color filter substrate, and the subpixels SPr, SPg and SPb as shown in FIG. 2 are formed in a matrix form. The subpixels SPr, SPg and SPb are defined by the data lines D1 to D3 and the gate lines G1 and G2 formed so as to cross each other on the TFT substrate. The TFT formed at the intersection of the data lines D1 to D3 and the gate lines G1 and G2 is connected to the data line D1 through the data lines D1 in response to the gate signal supplied from the gate line G1. To the pixel electrode of the liquid crystal cell. In addition, a common voltage is supplied to the common electrode facing the pixel electrode, and the liquid crystal layer is driven by the difference between the voltage supplied to the pixel electrode and the common electrode. The common electrode is formed on a color filter substrate in a vertical field driving method such as a TN (Twisted Nematic) mode and a VA (Vertical Alignment) mode, and a horizontal electric field such as IPS (In Plane Switching) mode and FFS (Fringe Field Switching) Is formed on the TFT substrate together with the pixel electrode in the driving method. The liquid crystal mode of the liquid crystal panel (LCD) can be implemented in any liquid crystal mode as well as the TN mode, the VA mode, the IPS mode, and the FFS mode. A polarizing plate is attached to each of the color filter substrate and the TFT substrate of the liquid crystal panel (LCD), and an alignment film for setting a pre-tilt angle of the liquid crystal is formed. The stereoscopic image display panel (PNL) configured as described above can display an image by the light provided from the backlight unit (BLU).

The backlight unit BLU is driven under the control of the dimming control unit 140 to provide light to the stereoscopic image display panel PNL. The backlight unit BLU includes a light source for emitting light, a light guide plate for guiding the light emitted from the light source toward the liquid crystal panel (LCD), an optical member for diffusing and condensing the light emitted from the light guide plate, and the like. The backlight unit (BLU) is composed of an edge type, a dual type, a quad type, and a direct type. In the edge type, a light source is arranged on one side of a liquid crystal panel (LCD), a dual type is a light source is arranged on both sides of a liquid crystal panel (LCD), and a quad type is a light source is arranged on all sides of a liquid crystal panel And the direct type is a type in which a light source is disposed below a liquid crystal panel (LCD).

The image supply unit 110 generates a 2D image signal in a two-dimensional mode (2D mode) and a 3D image signal in a three-dimensional mode (3D mode). The image supply unit 110 supplies the timing control unit 120 with a timing signal and a video signal such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE, and a main clock . The image supply unit 110 generates a video signal corresponding to the selected 2D or 3D mode according to user selection input through the user interface, and supplies the generated video signal to the timing controller 120. The user interface includes user input means such as an OSD (On Screen Display), a remote controller, a keyboard, and a mouse. Hereinafter, an example in which the image supply unit 110 is selected as a 3D mode and a 3D image signal is supplied to the timing control unit 120 will be described as an example.

The timing controller 120 receives a 3D image signal including a left eye image signal and a right eye image signal from the image supply unit 110. The timing controller 120 alternately supplies the left eye image signal and the right eye image signal to the driving unit 130 at a frame frequency of 120 Hz or more. Also, the timing controller 120 supplies a control signal corresponding to the 3D video signal to the driving unit 130.

The driving unit 130 includes a data driver connected to the data lines D1 through D3 to supply a data signal and a gate driver connected to the gate lines G1 and G2 to supply a gate signal. The driving unit 130 converts the left and right eye image signals of the digital form into the left and right eye image signals of the positive / negative analog form under the control of the timing controller 120 and supplies the converted signals to the data lines D1 to D3 . The driving unit 130 sequentially supplies gate signals to the gate lines G1 and G2 under the control of the timing controller 120. [

The dimming control unit 140 controls the backlight unit BLU to distinguish between when the stereoscopic image display panel PNL is driven in the two dimensional image mode and when the stereoscopic image display panel PNL is driven in the three dimensional image mode, do. This will be described in more detail below.

The stereoscopic image display apparatus having the above configuration can be driven as shown in FIG. As shown in FIG. 3, the left eye image LEFT is displayed on the stereoscopic image display panel PNL during the (N-1) th frame (Frame [n-1]) and light is emitted from the backlight unit BLU. Then, the viewer can see the left eye image through the left eyeglasses of the stereoscopic glasses (GLS). On the other hand, the right eye image RIGHT is displayed on the stereoscopic image display panel PNL during the Nth frame (Frame [n]), and light is emitted from the backlight unit BLU. Then, the viewer can see the right eye image through the right eye glasses of the stereoscopic glasses (GLS). According to the above operation, the left eye image and the right eye image are alternately displayed for each frame in the stereoscopic image display panel PNL, and when the light is emitted from the backlight unit BLU, the stereoscopic viewer views the 3D stereoscopic image through the stereoscopic glasses GLS. .

Hereinafter, a stereoscopic image display device according to an embodiment of the present invention will be described in more detail.

FIG. 4 is a view for schematically explaining a local dimming method of a stereoscopic image display apparatus according to an embodiment of the present invention. FIG. 5 is a block diagram of a local dimming method for a three-dimensional image of a stereoscopic image display apparatus according to an exemplary embodiment of the present invention. FIG. 6 is a diagram for explaining frame-by-frame operation by the local dimming method of FIG. 5, and FIGS. 7 and 8 show a local dimming method according to a comparative example and a local dimming method Fig.

1 to 4, in the stereoscopic image display apparatus according to an embodiment of the present invention, the local dimming method of the backlight unit (BLU) differs for 2D and 3D by the dimming control unit 140. The dimming control unit 140 determines whether the supplied video signal is a 2D video signal or a 3D video signal when a video signal is supplied to the timing controller 120 at step S110. If the video signal is a 2D video signal (Yes), the local dimming algorithm for 2D is selected (S140) and the backlight unit (BLU) is locally dimmed by the 2D local dimming algorithm (S180) If the supplied video signal is a 3D video signal (No), a 3D local dimming algorithm is selected (S160), and the backlight unit (BLU) is locally dimmed by the 3D local dimming algorithm (S180)

1 to 5, if the video signal supplied to the timing controller 120 is a 3D video signal, the dimming controller 140 performs the following steps To local dimming the backlight unit (BLU).

When the first left eye image is supplied to the timing controller 120 (S210), the first left eye image is held until the first right eye image is supplied. The timing controller 120 stores the first left eye image to hold the first left eye image (S230)

When the first right eye image is supplied to the timing controller 120 (S250), the first left eye image and the first right eye image to be supplied to the stereoscopic image display panel PNL are subjected to image compensation. In addition, the dimming control unit 140 performs local dimming of the backlight unit (BLU) based on the control signal provided from the timing control unit 120 (S270)

The timing controller 120 supplies the compensated first left eye image and the first right eye image to the driving unit 130 so that the compensated first left eye image and the first right eye image are supplied to the stereoscopic image display panel PNL. At this time, the dimming control unit 140 controls the backlight unit (BLU) to maintain the same local dimming state during the frame in which the first left eye image and the first right eye image are displayed (S290)

1 to 6, when both the first left-eye image L [N-1] and the first right-eye image R [N-1] are supplied to the timing controller 120 Performs local dimming in addition to image compensation for the first left eye image L [N-1] and the first right eye image R [N-1]. (The compensated L [N-1]) and the first right eye image (compensated R [N-1]) compensated by the timing controller 120 are supplied to the liquid crystal panel do. Accordingly, the liquid crystal panel LCD displays the 3D image of the [N-1] and the backlight unit BLU displays the 3D image of the [N-1] The same local dimming state is maintained. Here, the first left eye image L [N-1] and the first right eye image R [N-1] are supplied to the timing control unit 120 with a time difference of one frame, N] and the second right eye image R [N] have such a time difference.

The dimming control unit 140 controls the dimming control unit 140 to display a frame L (N-1) in which the first left eye image L [N-1] and the first right eye image R [N-1] are displayed on the stereoscopic image display panel PNL , R frame), the backlight unit (BLU) is controlled to maintain the same local dimming state. Accordingly, the backlight unit BLU is provided with the frames (L, R (N)) in which the first left eye image L [N-1] and the first right eye image R [N-1] are displayed on the stereoscopic image display panel PNL Frame) can be displayed. More specifically, the dimming control unit 140 controls the backlight unit (BLU) to perform local dimming at least once every two frames. Thus, the backlight unit BLU displays the same luminance (luminance) for two frames in which the first left-eye image L [N-1] and the first right-eye image R [N-1] are displayed on the stereoscopic image display panel PNL . ≪ / RTI > The compensated first left eye image (compensated L [N-1]) and the compensated first right eye image (compensated R [N-1]) are compensated by the timing control unit 120 and the dimming control unit 140, Is displayed on the stereoscopic image display panel PNL is shorter than the timing when the first left eye image L [N-1] and the first right eye image R [N-1] are supplied to the timing controller 120 At least one frame is delayed.

1 to 7, a dimming method of a conventional backlight unit (BLU) is a method in which a first left eye image L [N-1] and a second left eye image L [N-1] are displayed on a stereoscopic image display panel PNL (15%, 13%) during the two frames in which the first right eye image R [N-1] is displayed. This is because local dimming is performed every frame. 7, OFF indicates a state in which the backlight unit (BLU) is turned off, and ON indicates a state in which the backlight unit (BLU) is turned on.

In the conventional stereoscopic image display apparatus, as shown in FIG. 8A, when the left eye image is processed, the adjacent block # 2 is turned on by a spatial filter. When processing the right eye image, block # 2 is turned off when the left eye image is processed or darker than the previous frame. Therefore, if the left eye and right eye images are recognized as one 3D frame, the luminance should be the same at each point, but the luminance will change as the backlight unit (BLU) is modulated. That is, the backlight unit (BLU) recognizes the backlight unit (BLU) as flashing and generates crosstalk while recognizing the left eye and right eye images as one frame, thereby increasing eye fatigue . In Fig. 8, the numeral is the luminance value at the corresponding measurement position.

On the other hand, the dimming method (b) of the backlight unit BLU according to the embodiment differs from the first embodiment in that the first left eye image L [N-1] and the first right eye image R [N-1 ) Is locally dimmed to exhibit the same luminance (14%, 14%) for two frames displayed. This is because the local dimming is performed at least once every two frames.

In the stereoscopic image display apparatus according to the above-described driving method, as shown in FIG. 8B, the backlight unit BLU maintains the same luminance value while the left eye and the right eye images are sequentially displayed at the measurement point , Crosstalk, halo, and flashing are expected to be reduced. In addition, the fatigue of the eyebrows is also expected to be reduced. Here, the states of the left eye image and the right eye image are not distinguished from each other because the left eye image and the right eye image are driven by the same local dimming method.

As described above, the present invention controls the backlight unit so that the local dimming is performed at least once every two frames, thereby improving the crosstalk occurring at the time of local dimming in the stereoscopic image display apparatus, and reducing halos and flashing phenomenon And a method of driving the stereoscopic image display apparatus. In the meantime, the present invention includes a control panel such as an active retarder panel in the construction of a stereoscopic image display device. However, the present invention can be applied to any stereoscopic image display device that local dims the backlight unit.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

110: image supply unit 120: timing control unit
130: driving unit 140: dimming control unit
BLU: backlight unit PNL: stereoscopic image display panel
GLS: stereoscopic glasses LCD: liquid crystal panel
ARP: Control Panel

Claims (10)

A stereoscopic image display panel;
A backlight unit for providing light to the stereoscopic image display panel;
A timing controller for supplying a left eye image and a right eye image to the stereoscopic image display panel; And
And a dimming controller for controlling the backlight unit to differentiate the local dimming of the backlight unit by dividing the time when the stereoscopic image display panel is driven in the two dimensional image mode and the time when the stereoscopic image is driven in the three dimensional image mode,
Wherein the dimming control unit comprises:
And controls the backlight unit to maintain the same local dimming state during a frame in which the first left eye image and the first right eye image are displayed on the stereoscopic image display panel. delete The method according to claim 1,
The backlight unit includes:
Wherein the stereoscopic image display panel displays the same luminance during a frame in which the first left eye image and the first right eye image are displayed. The method according to claim 1,
The backlight unit includes:
Wherein the stereoscopic image display panel displays the same luminance for two frames in which the first left eye image and the first right eye image are displayed. The method according to claim 1,
Wherein the dimming control unit comprises:
And controls the backlight unit to perform local dimming at least once every two frames. The method according to claim 1,
Wherein the timing control unit comprises:
When the first left eye image is supplied, the first left eye image is held until the first right eye image is supplied, and when the first right eye image is supplied to the timing control unit, the compensated first left eye image And the first right eye image is generated. The method according to claim 6,
Wherein the compensated first left-eye image and the compensated first right-eye image are displayed on the stereoscopic image display panel,
Wherein the timing control unit is delayed by at least one frame from a timing at which the first left eye image and the first right eye image are supplied. When the first left eye image is supplied to the timing control unit, holding the first left eye image until a first right eye image is supplied;
Performing image compensation on the first left eye image and the first right eye image to be supplied to the stereoscopic image display panel when the first right eye image is supplied to the timing control unit; And
And controlling the backlight unit to maintain the same local dimming state during the frame in which the first left eye image and the first right eye image are displayed, performing local dimming of the backlight unit together with the image compensation, A method of driving a device. 9. The method of claim 8,
The step of controlling the backlight unit includes:
And controls the backlight unit to display the same luminance during a frame in which the first left eye image and the first right eye image are displayed on the stereoscopic image display panel. 9. The method of claim 8,
The backlight unit includes:
And displaying the same luminance for two frames in which the first left eye image and the first right eye image are displayed on the stereoscopic image display panel.

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