KR20120023429A - Stereoscopic image display device and driving method the same - Google Patents

Abstract

PURPOSE: A stereoscopic image display device and a driving method the same are provided to improve a cross-talk by controlling a backlight unit performing local dimming at least two frames. CONSTITUTION: A backlight unit(BLU) supplies light to an image display panel. A timing controller(120) supplies a left image and a right image to a stereoscopic image display panel. The timing controller(140) controls the backlight unit. Two-dimensional image mode and the stereoscopic image mode are classified by a dimming controller. The dimming controller controls a back light unit to maintain local dimming state.

Description

Stereoscopic Image Display Device and Driving Method {Stereoscopic Image Display Device and Driving Method the same}

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

The stereoscopic image display apparatus is divided into a binocular parallax technique and an autostereoscopic technique.

The binocular parallax method uses a parallax image of left and right eyes having a large stereoscopic effect. There are two types of binocular parallax: glasses and no glasses. The spectacle method displays a time-division method by changing the polarization direction of left and right parallax images on a direct view stereoscopic display panel or a projector, and realizes a stereoscopic image using polarized glasses or liquid crystal shutter glasses. In the autostereoscopic method, an optical plate such as a parallax barrier for separating an optical axis of left and right parallax images is generally installed in front of or behind a stereoscopic image display panel.

Recently, a stereoscopic image display device is an organic light emitting display device (OLED), a liquid crystal display device (LCD), and a plasma display panel (PDP). Various flat panel display devices are used. Among them, a liquid crystal display uses a method of global dimming and local dimming of the backlight unit in order to reduce power consumption while improving image contrast in a screen.

In the 3D image mode, the video signal is inputted alternately to the left eye image and the right eye image by frame. When 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 of the three-dimensional image is caused by a flashing phenomenon. In other words, when a three-dimensional image is displayed on the stereoscopic image display apparatus, the human eye recognizes one three-dimensional image in which left and right images are combined in one frame section, while the backlight unit is modulated twice by local dimming. Therefore, a stereoscopic image display device implemented with a conventional stereoscopic image display panel is required to improve the crosstalk caused by local dimming.

Embodiments of the present invention to solve the above-described problems of the prior art, a three-dimensional that can reduce the halo (flashing) phenomenon as well as improve crosstalk generated when local dimming in the stereoscopic image display device An image display device and a driving method thereof are provided.

Embodiments of the present invention as a means for solving the above problems, three-dimensional image display panel; A backlight unit providing light to the stereoscopic image display panel; A timing controller supplying a left eye image and a right eye image to a stereoscopic image display panel; And a dimming control unit which controls the backlight unit but distinguishes when the stereoscopic image display panel is driven in the two-dimensional image mode and when the three-dimensional image mode is driven.

The dimming controller 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 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.

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

When the first left eye image is supplied, the timing controller is configured to hold the first left eye image until a section in which the first right eye image is supplied, and when the first right eye image is supplied to the timing controller, the timing controller performs image compensation to compensate for the first left eye image. A compensated first right eye image may be generated.

The time point 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 at least one frame later than the time point at which the first left eye image and the first right eye image are supplied to the timing controller.

In another aspect, an embodiment of the present invention, if the first left eye image is supplied to the timing control unit, the step of holding the first left eye image up to the section in which the 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 controller; And performing local dimming of the backlight unit together with image compensation, 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. Provide a method.

In the controlling of the backlight unit, the backlight unit may be controlled 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.

The backlight unit may display 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.

According to an embodiment of the present invention, the backlight unit is controlled to perform local dimming at least once every two frames, thereby improving crosstalk generated during local dimming in the stereoscopic image display device, as well as halo and flashing. There is an effect of providing a three-dimensional image display device and a driving method thereof that can be reduced.

1 is a schematic configuration diagram of a stereoscopic image display device 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.
3 is a view for explaining a driving concept of a stereoscopic image display device.
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.
5 is a flowchart illustrating a local dimming method for a three-dimensional image of the stereoscopic image display apparatus according to an embodiment of the present invention.
FIG. 6 is a view for explaining an operation of each frame according to the local dimming method of FIG. 5. FIG.
7 and 8 are views for comparing a local dimming method according to a comparative example and a local dimming method according to an embodiment.

Hereinafter, with reference to the accompanying drawings, the specific content for the practice of the present invention will be described.

1 is a schematic configuration diagram of a stereoscopic image display device 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, and FIG. It is a figure for demonstrating a driving concept.

As shown in 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), And 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 an 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 driver 130 and displays a two-dimensional image or a three-dimensional image correspondingly. The control panel ARP included in the stereoscopic image display panel PNL is controlled by the timing controller 120 to separate an image displayed on the liquid crystal panel LCD into a left eye image and a right eye image, or a similar function. It can be composed of panels to perform. However, when the stereoscopic glasses GLS are configured in the liquid crystal shutter method, the control panel ARP is omitted. That is, the control panel ARP may be included or omitted in the stereoscopic image display panel PNL according to a method of implementing a 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, and a color filter substrate on which a color filter and a black matrix are formed. It includes. A liquid crystal layer is formed between the TFT substrate and the color filter substrate of the liquid crystal panel LCD, and the sub pixels SPr, SPg, and SPb shown in FIG. 2 are formed in a matrix form. The sub pixels SPr, SPg, and SPb are defined by the data lines D1 to D3 and the gate lines G1 and G2 formed 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 a data signal supplied via the data lines D1 in response to a gate signal supplied from the gate line G1. Is supplied 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 voltages supplied to the pixel electrode and the common electrode. The common electrode is formed on the color filter substrate in a vertical electric field driving method such as twisted nematic (TN) mode and vertical alignment (VA) mode, and a horizontal electric field such as IPS (In Plane Switching) mode and FFS (Fringe Field Switching) mode. In the driving method, a pixel electrode is formed on the TFT substrate. The liquid crystal mode of the liquid crystal panel (LCD) can be implemented in any liquid crystal mode as well as the TN mode, VA mode, IPS mode, FFS mode. Polarizing plates are attached to the color filter substrate and the TFT substrate of the liquid crystal panel (LCD), respectively, and an alignment film for setting the 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 controller 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 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 edge type, dual type, quad type and direct type. In the edge type, the light source is disposed on one side of the liquid crystal panel (LCD), and the dual type is the type in which the light source is disposed opposite to both sides of the liquid crystal panel (LCD). In the quad type, the light source is disposed on all sides of the liquid crystal panel (LCD). The direct type is a form in which a light source is disposed below the liquid crystal panel (LCD).

The image supply unit 110 generates a 2D video signal in the two-dimensional mode (2D mode), and generates a 3D video signal in the three-dimensional mode (3D mode). The image supply unit 110 supplies timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE, and a main clock to the timing controller 120. . The image supply unit 110 selects a 2D or 3D mode according to a user selection input through the user interface, generates an image signal corresponding thereto, and supplies the image signal to the timing controller 120. The user interface includes user input means such as an on screen display (OSD), a remote controller, a keyboard, and a mouse. Hereinafter, as an example, the image supply unit 110 is selected as the 3D mode and supplies the 3D image signal to the timing controller 120.

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 driver 130 at a frame frequency of 120 Hz or more. In addition, the timing controller 120 supplies a control signal corresponding to the 3D image signal to the driver 130.

The driver 130 includes a data driver connected to the data lines D1 to D3 to supply a data signal, and a gate driver connected to the gate lines G1 and G2 to supply a gate signal. Under the control of the timing controller 120, the driver 130 converts the digital left eye and right eye image signals into positive and negative analog left eye and right eye image signals and supplies them to the data lines D1 to D3. . In addition, the driver 130 sequentially supplies the 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, but distinguishes the local dimming of the backlight unit BLU by distinguishing when the stereoscopic image display panel PNL is driven in the two-dimensional image mode and the three-dimensional image mode. do. This will be described in more detail below.

The stereoscopic image display device having the above configuration can be driven as shown in FIG. 3. As illustrated in FIG. 3, the left eye image LEFT is displayed on the stereoscopic image display panel PNL during the N-th th frame Frame [n-1], and light is emitted from the backlight unit BLU. Then, the viewer can view the left eye image through the left glasses of the stereoscopic glasses (GLS). In contrast, during the Nth frame Frame [n], the right eye image RIGHT is displayed on the stereoscopic image display panel PNL and light is emitted from the backlight unit BLU. Then, the viewer can view 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 on the stereoscopic image display panel (PNL), and when the light is emitted from the backlight unit (BLU), the viewer views the 3D stereoscopic image through the stereoscopic glasses (GLS). You can do it.

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

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, Figure 5 is a local dimming of a three-dimensional image of the stereoscopic image display apparatus according to an embodiment of the present invention 6 is a flowchart illustrating a method for each frame according to the local dimming method of FIG. 5, and FIGS. 7 and 8 are a local dimming method according to a comparative example and a local dimming method according to an embodiment. A diagram for comparing and explaining.

As shown in FIGS. 1 to 4, in the 3D image display device according to the exemplary embodiment, the dimming control unit 140 changes the local dimming method of the backlight unit BLU for 2D and 3D. When the video signal is supplied to the timing controller 120 (S110), the dimming controller 140 determines whether the supplied video signal is a 2D video signal or a 3D video signal (S120). 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 using the 2D local dimming algorithm (S180). In contrast, the dimming controller 140 If the supplied video signal is a 3D video signal (No), the 3D local dimming algorithm is selected (S160), and the backlight unit BLU is locally dimmed using the 3D local dimming algorithm (S180).

1 to 5, in the stereoscopic image display apparatus according to an embodiment of the present invention, if the image signal supplied to the timing controller 120 is a 3D image signal, the dimming controller 140 performs the following process. Local dimming of 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), image compensation is performed on the first left eye image and the first right eye image to be supplied to the stereoscopic image display panel PNL. In addition, the dimming controller 140 performs local dimming of the backlight unit BLU based on the control signal provided from the timing controller 120 (S270).

The timing controller 120 supplies the corresponding image to the driver 130 such that the compensated first left eye image and the first right eye image are supplied to the stereoscopic image display panel PNL. In this case, the dimming controller 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 to assist in the above description, the timing controller 120 is supplied with both the first left eye image L [N-1] and the first right eye image R [N-1]. Local dimming is performed along with image compensation for the first left eye image L [N-1] and the first right eye image R [N-1]. The first left eye image (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 LCD through the data driver. do. Accordingly, the liquid crystal panel LCD displays the 3D image of the [N-1] th and the backlight unit BLU displays the left and right eye frames (L, R frames) on which the 3D image of the [N-1] is displayed. Keep the same local dimming state. Here, 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 a time difference of one frame. N]) and the second right eye image R [N] have the same time difference.

According to an embodiment, the dimming controller 140 may display a frame L on 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. The backlight unit BLU is controlled to maintain the same local dimming state during the R frame). Accordingly, the backlight unit BLU includes the frames L and R on 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. The same luminance during a frame). In more detail, the dimming controller 140 controls the backlight unit BLU to perform local dimming at least once every two frames. Accordingly, the backlight unit BLU has the same 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. Will be displayed. As the timing controller 120 and the dimming controller 140 operate as described above, the compensated first left eye image (compensated L [N-1]) and the compensated first right eye image (compensated R [N-1]) ) Is displayed on the stereoscopic image display panel PNL than 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 to assist in the above description, the conventional dimming method of the backlight unit (BLU) (a) is a stereoscopic image display panel (PNL) and the first left eye image (L [N-1]) During the two frames in which the first right eye image R [N-1] is displayed, it is locally dimmed to display different luminance (15%, 13%). This is because local dimming is performed every frame. In FIG. 7, OFF indicates a state where the backlight unit BLU is turned off and ON indicates a state where the backlight unit BLU is turned on.

As shown in FIG. 8A, when the stereoscopic image display apparatus processes the left eye image by the above driving method, 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 turned darker than the previous frame. Therefore, when the left eye and the right eye image are recognized as one 3D frame, the luminance should be the same at each point, but the luminance changes as the backlight unit BLU is modulated. That is, since the brightness of the backlight unit BLU changes while the viewer's eye recognizes the left eye and right eye images as one frame, the backlight unit BLU is recognized as flashing or generates crosstalk, which increases eye fatigue. Done. In Fig. 8, the numerals represent the luminance values at the corresponding measuring positions.

On the other hand, (b) which is a dimming method of the backlight unit BLU according to the embodiment, 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. ]) Is locally dimmed to represent the same luminance (14%, 14%) for the two frames displayed. This is because local dimming is performed at least once every two frames.

According to the driving method as described above, in the stereoscopic image display device according to the embodiment, as shown in FIG. 8B, the backlight unit BLU maintains the same luminance value while the left eye and right eye images are sequentially displayed at the measurement points. Crosstalk, halo and flashing are expected to be reduced. In addition, eye fatigue of the viewer is also expected to be reduced. Here, the state of the left eye image and the right eye image is not illustrated separately because the left eye image and the right eye image are driven by the same local dimming method, and thus the luminance values of the measurement positions are also the same.

As described above, the present invention can control the backlight unit so that local dimming is performed at least once every two frames, thereby improving crosstalk generated during local dimming in the stereoscopic image display device, as well as reducing halo and flashing. It is effective to provide a stereoscopic image display device and a driving method thereof. Meanwhile, the present invention exemplifies that a control panel such as an active retarder panel is included in the configuration of the stereoscopic image display device. However, the present invention may be applied to any stereoscopic image display device that locally dims the backlight unit.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above may be modified in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in 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 display panel
GLS: Stereoscopic Glasses LCD: Liquid Crystal Panel
ARP: Control Panel

Claims (10)

Stereoscopic image display panel;
A backlight unit providing light to the stereoscopic image display panel;
A timing controller supplying a left eye image and a right eye image to the stereoscopic image display panel; And
And a dimming controller configured to control the backlight unit and to differentiate the local dimming of the backlight unit by dividing when the stereoscopic image display panel is driven in the two-dimensional image mode and the three-dimensional image mode. The method of claim 1,
The dimming control unit,
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 on the stereoscopic image display panel. The method of claim 2,
The backlight unit,
And displaying 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 method of claim 2,
The backlight unit,
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. The method of claim 1,
The dimming control unit,
And the backlight unit controls local dimming once in at least two frames. The method of claim 1,
The timing control unit,
When the first left eye image is supplied, the first left eye image is held until a section in which the first right eye image is supplied, and when the first right eye image is supplied to the timing controller, image compensation is performed to compensate for the first left eye image. And a first right eye image. The method of claim 6,
When the compensated first left eye image and the compensated first right eye image are displayed on the stereoscopic image display panel,
And at least one frame later than a time point at which the first left eye image and the first right eye image are supplied to the timing controller. If the first left eye image is supplied to a timing controller, holding the first left eye image until a section in which the 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 a stereoscopic image display panel when the first right eye image is supplied to the timing controller; And
And performing a local dimming of the backlight unit together with the image compensation, 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. Method of driving display device. The method of claim 8,
Controlling the backlight unit,
And controlling 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. The method of claim 8,
The backlight unit,
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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