KR102131770B1 - Method of driving display device - Google Patents

Abstract

The present invention relates to a method of driving a display device, the method comprising: displaying a left-eye image in a 1/2 block divided within a screen of a display panel in a first image data address period shortened within a first frame period; Displaying a first black image on the screen in a first blank period secured by a shortening of the first image data address period within the first frame period; Displaying a right-eye image in the remaining 1/2 block of the screen in a second image data address period shortened within a second frame period; Displaying a second black image on the screen in a second blank period secured by a reduction in the second image data address period within the second frame period; And the 3D filter and the backlight unit so that the 3D filter is switched within the first and second blank periods, and the backlight unit is turned off within the first and second blank periods in synchronization with the switching of the 3D filter. And controlling.

Description

Method of driving a display device {METHOD OF DRIVING DISPLAY DEVICE}

The present invention relates to a stereoscopic image display device, and more particularly, to a driving method of a display device capable of increasing display quality by reducing cross talk of a glasses-free 3D display device.

2. Description of the Related Art User demand for realistic images has increased, and a stereoscopic image display device capable of displaying not only two-dimensional (2D) images but also three-dimensional (3D) images has been developed.

The stereoscopic (3D) image display apparatus can display an image that is not a two-dimensional plane as a three-dimensional stereoscopic image, so that the original three-dimensional information of the object can be completely transmitted to the user. Therefore, it is possible to express a 3D image that is much more realistic and realistic than a conventional 2D display device.

The stereoscopic (3D) image display apparatus displays an image in three dimensions by using a perspective view when different image signals perceived by both eyes are synthesized.

As a method of realizing a stereoscopic image, there are largely known a stereoscopic technique, a volumetric technique, and a holographic technique. Among them, the binocular parallax method may be divided into a glasses method and a glasses-free method, and the glasses-free method has been actively studied in recent years.

By outputting the stereoscopic image data through the stereoscopic (3D) image display device using the autostereoscopic method, the user can watch the stereoscopic image even without wearing glasses. The autostereoscopic method includes a parallax barrier or lensticularlens (hereinafter simply referred to as a '3D filter') on the front of the panel.

1 is a view schematically showing an autostereoscopic 3D display device according to the prior art, and FIG. 2 is a view showing a method of driving the autostereoscopic 3D display device according to the prior art.

1 and 2, the autostereoscopic 3D display device according to the related art includes a display panel 10 displaying a left-eye image and a right-eye image, a backlight unit 20 including a light source, and a backlight unit 20 ) Includes a light guide panel 30 and a 3D filter 40 that guide light generated from the display panel 10 to the display panel 10.

The display panel 10 of the autostereoscopic 3D image display device is driven at a frame frequency of 2 times or more when compared with a display device displaying a 2D image, and alternates a left image and a right image in a time division manner. Mark it as an enemy.

In accordance with the addressing time of image data (Image Data Addressing Timing), the 3D filter 40 and the backlight unit are sequentially turned on from the top to the bottom of the display panel to display the left-eye image and the right-eye image.

When the liquid crystal panel is applied to the display panel 10, the transitional image data may be perceived by the viewer in a section in which the liquid crystal rotates. To prevent this, the backlight unit BLU is turned off and the 3D filter 40 is switched at the same time during the rotation of the liquid crystal.

After both the rotation of the liquid crystal and the switching of the 3D filter 40 are completed, the backlight unit 20 is turned on to display a stereoscopic image in a time-division manner to the viewer.

If an OLED panel is applied as a display panel, light emission of the pixels may be turned off only during a switching period of the 3D filter 40.

3 is a view showing a scanning backlight unit and an inverter of the autostereoscopic 3D display device according to the prior art, and FIG. 4 is a view showing a 3D filter and a switching circuit of the 3D filter of the autostereoscopic 3D display device according to the prior art .

Referring to FIGS. 3 and 4, the autostereoscopic 3D display device according to the related art requires a plurality of segment inverters and a backlight unit 20 capable of scanning compared to a spatial division type stereoscopic image display device. The manufacturing cost increases because the condensed light guide panel 30 is required. In addition, there is a problem in that manufacturing cost increases due to the need for a switching circuit for driving the 3D filter 40 by scanning.

In the case of time-division driving, there is a limitation in precisely matching the rotation time of the liquid crystal and the switching time of the 3D filter 40, and due to the mixture between the image of the previous frame (Previous Frame Image) and the image of the current frame (Present Frame Image) Crosstalk occurs to degrade display quality.

In addition, by sequentially driving each block, there is a time difference between the top and bottom of the block in one block, and the time difference between the response time of the liquid crystal, the response time of the 3D filter 40 and the backlight unit 20 is also within the block due to the time difference. If the off time is not exactly matched, there is a problem in that crosstalk occurs.

The present invention is to solve the above-mentioned problems, and it is a technical problem to provide a driving method of a stereoscopic image display device capable of improving display quality by removing 3D crosstalk.

The present invention is to solve the above-mentioned problems, it is a technical problem to reduce the manufacturing cost by simplifying the backlight unit (BLU), light guide panel (LGP) and 3D filter.

In addition to the technical problems of the present invention mentioned above, other features and advantages of the present invention are described below, or it will be clearly understood by those skilled in the art from the description and description.

A method of driving a display apparatus according to an embodiment of the present invention includes displaying a left-eye image in a 1/2 block divided within a screen of a display panel in a first image data address period shortened within a first frame period; Displaying a first black image on the screen in a first blank period secured by a shortening of the first image data address period within the first frame period; Displaying a right-eye image in the remaining 1/2 block of the screen in a second image data address period shortened within a second frame period; Displaying a second black image on the screen in a second blank period secured by a reduction in the second image data address period within the second frame period; And the 3D filter and the backlight unit so that the 3D filter is switched within the first and second blank periods, and the backlight unit is turned off within the first and second blank periods in synchronization with the switching of the 3D filter. And controlling.
A method of driving a display device according to another embodiment of the present invention displays a video for a first viewer in a 1/2 block divided within a screen of the display panel in a first image data address period shortened within a first frame period. To do; Displaying a first black image on the screen in a first blank period secured by a shortening of the first image data address period within the first frame period; Displaying a second viewer image in the remaining 1/2 block of the screen in a second image data address period shortened within a second frame period; Displaying a second black image on the screen in a second blank period secured by a reduction in the second image data address period within the second frame period; And the 3D filter and the backlight so that the 3D filter is switched within the first and second blank periods, and the backlight unit is turned off within the first and second blank periods in synchronization with the switching of the 3D filter. And controlling the unit.

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The driving method of the stereoscopic image display device of the present invention can improve display quality by removing 3D crosstalk.

The present invention simplifies the backlight unit (BLU), the light guide panel (LGP), and the 3D filter, thereby reducing manufacturing cost.

In addition, other features and advantages of the present invention may be newly identified through embodiments of the present invention.

1 is a view schematically showing a display device according to the prior art.
2 is a view showing a method of driving a display device according to the prior art.
3 is a view showing a scanning backlight unit and an inverter of a display device according to the prior art.
4 is a view showing a 3D filter and a switching circuit of a 3D filter of a display device according to the prior art.
5 is a view schematically showing a display device according to an embodiment of the present invention.
6 is a view showing a method of driving a display device according to an embodiment of the present invention.
7 is a view showing a scanning backlight unit and an inverter of a display device according to an embodiment of the present invention.
8 is a diagram illustrating a 3D filter and a switching circuit of a 3D filter of a display device according to an embodiment of the present invention.

Hereinafter, a method of driving a display device according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

Prior to the description with reference to the drawings, the display panel may vary depending on the method of adjusting the arrangement of the liquid crystal, such as TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, IPS (In Plane Switching) mode, FFS (Fringe Field Switching) mode, etc. Has been developed.

The TN mode, the VA mode, the IPS mode, and the FFS mode may be applied to the driving method of the stereoscopic image display device of the present invention without limitation to the display mode, and may be applied to other flat panel display panels other than the liquid crystal panel.

Since the method of driving the stereoscopic image display apparatus according to an embodiment of the present invention reduces crosstalk of 2D images and cuts manufacturing costs, it is important to display 2D images and crosstalk of 3D images. Detailed description is omitted.

5 is a view schematically showing a display device according to an embodiment of the present invention, and FIG. 6 is a view showing a method of driving a display device according to an embodiment of the present invention.

5 and 6, a display device according to an exemplary embodiment of the present invention includes a display panel 110, a backlight unit 120, a light guide panel 130, a 3D filter 140, and a driving circuit unit (not shown) ).

The driving circuit part driving the display panel 110 and the 3D filter 140 may include a timing controller (T-con), a data driver (D-IC), a gate driver (G-IC), a backlight driver, and a power supply. have.

Since the driving circuit portion includes the same configuration as the driving circuit portion of a general liquid crystal display (LCD), a detailed description of its configuration and driving method will be omitted.

The display panel 110 includes a lower substrate (TFT array substrate), an upper substrate (color filter array substrate), and a liquid crystal layer interposed between the two substrates.

A plurality of pixels are defined by crossing data lines and gate lines on a lower substrate (TFT array substrate), and the plurality of pixels include a thin film transistor (TFT), a storage capacitor (Cst), and a pixel electrode. Is formed. Red, green, and blue color filters are formed on the upper substrate (color filter array substrate), and common electrodes corresponding to pixel electrodes formed on the lower substrate (TFT array substrate) are formed.

The backlight units 120 and BLU include a plurality of light sources for generating light (CCFL, EEFL or LED) and a plurality of optical sheets for improving the efficiency of the light generated by the light sources.

The backlight driving unit included in the driving circuit unit controls driving of the plurality of light sources based on image data supplied to the display panel 110.

The liquid crystal alignment of the liquid crystal layer is controlled by an electric field formed between the pixel electrode and the common electrode of the display panel 110 to control the transmittance of light received from the backlight unit, thereby displaying an image.

The display panel 110 including the above-described configuration drives a plurality of pixels according to input image data to display an image. The plurality of pixels is composed of red pixels, green pixels, and blue pixels, and three color pixels, that is, red pixels, green pixels, and blue pixels, constitute one unit pixel to display an image.

Here, in the case of displaying a 2D image, all pixels are driven to display the image without distinguishing the left-eye image and the right-eye image, and when the image is displayed, the entire block of the 3D filter 140 is turned on to display the 2D image. It can be made aware of this viewer.

Meanwhile, when a 3D image is displayed, a left-eye image is displayed on the display panel 110 on a first frame in a time division manner, and 1/2 of the blocks of the 3D filter 140 are turned on. Let the left eye video be perceived by the viewer.

Then, in the second frame, the right-eye image is displayed on the display panel 110, and the other half of the blocks of the 3D filter 140 is turned on to recognize the right-eye image to the viewer.

The left-eye image and the right-eye image displayed on the display panel 110 are separated and recognized in the viewer's eyes, thereby realizing a three-dimensional image by binocular parallax.

In the above description, the display panel 110 is described as being a liquid crystal panel for controlling light transmittance using liquid crystal, but this is an example of various embodiments of the present invention. In another embodiment of the present invention, an organic light emitting diode (OLED) display panel may be applied as the display panel 110.

In the display device according to an embodiment of the present invention, the display panel 110 is driven at a frame frequency of 200 to 240 Hz, which is 4 times or more compared to the existing 50 to 60 Hz frame frequency. Then, the 3D filter 140 is driven at a driving frequency that is two times or more than that of the prior art 3D filter.

The image data of each frame is loaded to display an image, and a black image is inserted between frames. That is, the image data is addressed in the order of the left-eye image, black image, right-eye image, and black image and displayed on the screen.

In consideration of the response speed of the 3D filter 140 and the display panel, the data addressing time is shortened, and the 3D filter 140 is switched for a blank time increased by the shorted addressing time, and the backlight unit 120 Here, the 3D filter 140 is switched in the blank period after the black image data is addressed, and the backlight unit 120 is turned off in synchronization with the switching of the 3D filter 140. ) do.

Therefore, other images are not overlapped at the same time. That is, when the left-eye image is displayed, the right-eye image does not overlap, and when the right-eye image is displayed, the left-eye image does not overlap.

Here, it can be applied to a plurality of viewer displays (dual display, triple display) as well as 3D images. Accordingly, not only the left-eye image and the right-eye image are input for realizing a 3D image, but also a plurality of 2D images are input to display images independently to a plurality of viewers.

Depending on the response characteristics of the 3D filter 140, the image data addressing time is reduced within one frame. As an example, among the time it takes for the 3D filter 140 to turn on (3D Filter Turn On Time: Ton) and the time it takes for the 3D filter 140 to turn off (3D Filter Turn Off Time: Toff) Reduce the data addressing time within one frame for a longer time.

In accordance with the end of the black image data addressing, the backlight units 120 and BLU are turned off to remove 3D crosstalk caused by the backlight units 120 and BLU. Then, the 3D filter 140 is switched according to the off of the backlight units 120 and BLU to remove 3D crosstalk caused by the 3D filter 140.

That is, it blocks the overlapping of the left-eye and right-eye images, shortens the addressing time for the left-eye image data, the black-image data, and the right-eye image data, and turns off and off the backlight units 120 and BLU according to the time when the addressing of the black-image data ends. By switching the 3D filter 140, 3D crosstalk can be completely eliminated.

Specifically, in order to fundamentally remove 3D crosstalk by a time division method, when different types of images are displayed on the display panel 110 at the same time, 3D crosstalk occurs, and the display panel 110, The case where 3D crosstalk occurs due to the response characteristics of the backlight unit 120 and the 3D filter 140 is distinguished.

First, when different types of images are displayed at the same time, crosstalk occurs when the left-eye image and the right-eye image are simultaneously displayed on the display panel 110.

As shown in FIG. 6, the display device of the present invention does not display the right-eye image when the left-eye image is displayed on the display panel 110, and conversely, displays the left-eye image when the right-eye image is displayed on the display panel 110. I never do that.

To this end, image data is sequentially input in order of left eye image data, black image data, right eye image data, and black image data for each frame.

At this time, a black image is displayed after the left-eye image is displayed. Then, after the black image is displayed, the right-eye image is displayed and the black image is displayed again. As such, a black image is inserted between the left-eye image and the right-eye image so that the left-eye image and the right-eye image do not overlap.

As another example, the image data of the viewer 1 and the image data of the viewer 2 are alternately displayed, and black image data is inserted between the image of the viewer 1 and the image of the viewer 2 so that the images of the viewer 1 and 2 do not overlap. Can.

As illustrated in FIG. 6, black data is present between the addressing times of the image data to prevent overlapping between images.

As described above, when the two images are clearly separated, it is possible to prevent the occurrence of 3D crosstalk by displaying two kinds of images at the same time.

Next, a method of preventing the occurrence of 3D crosstalk due to the response characteristics of the display panel 110, the backlight unit 120, and the 3D filter 140 will be described.

When inputting the left and right image data according to the data addressing time of the prior art, the section switching the 3D filter and the left and right images may overlap, and the left and right images are not completely separated and overlap. When left and right images overlap, 3D crosstalk occurs.

The driving method of the stereoscopic image display apparatus according to an exemplary embodiment of the present invention shortens the data addressing time in each frame by a specific time, and addresses the left-eye image data and the right-eye image data.

Here, considering the response characteristics of the 3D filter 140, the data addressing time is shortened. The shortened data addressing switches the 3D filter 140 at a blank time secured by time.

In addition, in the period in which the 3D filter 140 switches, the backlight units 120 and BLU are turned off. When the backlight units 120 and BLU are turned off in a period in which the 3D filter 140 is switched, crosstalk due to light leakage can be prevented.

The method of reducing the data addressing time is as follows.

As shown in Equation 1 below, the data addressing time can be shortened.

<Equation 1>

Tad_prop = Tad_short / Tad_ori. ≒ Tad_short / {1/Frame Rate}

In Equation 1, Tad_prop is a shortening ratio of the data addressing time.

Tad_ori is an existing data addressing time, and Tad_short is a data addressing time shortening time. The addressing shortening time is the off time of the backlight unit (BLU Off Time).

The shortening time (Tad_short) of the data addressing time is Max{Ton, Toff}. Here, Ton means the turn-on time of the 3D filter 140. In addition, Toff means the turn-off time of the 3D filter 140 (3D Filter Turn Off Time: Toff).

The data addressing time is shortened by a longer time among the turn-on time of the 3D filter 140 and the turn-off time of the 3D filter 140 (3D Filter Turn Off Time: Toff).

That is, among Ton and Toff, if the time of Ton is long, the data addressing time is shortened by Ton. Conversely, among Ton and Toff, if the time of Toff is long, the data addressing time is reduced by Toff.

Accordingly, the clock frequency of the display panel 110 and the data drive IC (D-IC) should be increased by a rate at which the data addressing time is shortened.

The display device according to the exemplary embodiment of the present invention increases the clock frequency of the data drive IC (D-IC) by a reduced ratio of data addressing time.

The relationship between the 3D filter 140, the backlight units 120 and the BLU and the data addressing time has the following characteristics.

By reducing the data addressing time, after the black data is addressed, the 3D filter 140 is switched for a blank time before data of the next image is addressed.

The backlight units 120 and BLU are turned off simultaneously with the switching of the 3D filter 140. Through this, it is possible to prevent an image quality abnormality caused by switching of the 3D filter 140 and crosstalk caused by light leakage.

7 is a view showing a scanning backlight unit and an inverter of a display device according to an embodiment of the present invention, and FIG. 8 is a view showing a 3D filter and a switching circuit of a 3D filter of a display device according to an embodiment of the present invention.

Referring to FIGS. 7 and 8, the display device according to an embodiment of the present invention has a frame frequency of 200 to 240 Hz, which is more than 4 times that of the existing 50 to 60 Hz frame frequency, compared to the display panel 110 and 3D filters of the prior art. It includes a 3D filter 140 at a driving frequency more than twice.

Accordingly, the structures of the backlight units 120 and BLU, the light guide panel 130 and the 3D filter 140 are simplified to reduce manufacturing costs.

The 3D image can be displayed without using the scanning backlight used in the conventional time division driving method, and the cost of the backlight unit can be reduced by using a universal inverter without using an inverter for the scanning backlight.

In addition, since the switching circuit for driving the 3D filter 140 does not need to be driven for each region, it is possible to display a 3D image using only one switching circuit, thereby reducing manufacturing cost. In addition, the condensed light guide panel can be replaced with a general light guide panel, thereby reducing manufacturing cost.

Those skilled in the art to which the present invention pertains will understand that the above-described present invention can be implemented in other specific forms without changing its technical spirit or essential features. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

The scope of the present invention is indicated by the following claims rather than the above detailed description, and it should be interpreted that all changes or modifications derived from the meaning and scope of the claims and equivalent concepts are included in the scope of the present invention. do.

110: display panel
120: backlight unit
130: light guide panel
140: 3D filter

Claims (8)

A method of driving a display device including a display panel on which an image is displayed, a 3D filter disposed in front of a screen of the display panel, and a backlight unit disposed on a rear side of the display panel to irradiate light to the display panel,
Displaying a left-eye image in a 1/2 block divided within a screen of the display panel in a first image data address period shortened within a first frame period;
Displaying a first black image on the screen in a first blank period secured by a shortening of the first image data address period within the first frame period;
Displaying a right-eye image in the remaining 1/2 block of the screen in a second image data address period shortened within a second frame period;
Displaying a second black image on the screen in a second blank period secured by a reduction in the second image data address period within the second frame period; And
The 3D filter and the backlight unit such that the 3D filter is switched within the first and second blank periods, and the backlight unit is turned off within the first and second blank periods in synchronization with the switching of the 3D filter. And controlling the display device. According to claim 1,
And controlling the backlight unit to an on state when data addressing of the black image is finished. delete delete According to claim 1,
Among the response time characteristics of the 3D filter, the first and second image data address periods are shortened by a longer time from a turn-on time and a turn-off time. The method of claim 5,
And increasing a clock frequency of a data drive IC (D-IC) by a reduction ratio of the first and second image data address periods. According to claim 1,
A method of driving a display device, wherein the left-eye image and the right-eye image do not overlap on the screen at the same time. A method of driving a display device including a display panel on which an image is displayed, a 3D filter disposed in front of a screen of the display panel, and a backlight unit disposed on a rear side of the display panel to irradiate light to the display panel,
Displaying an image for a first viewer in a 1/2 block divided within a screen of the display panel in a first image data address period shortened within a first frame period;
Displaying a first black image on the screen in a first blank period secured by a shortening of the first image data address period within the first frame period;
Displaying a second viewer image in the remaining 1/2 block of the screen in a second image data address period shortened within a second frame period;
Displaying a second black image on the screen in a second blank period secured by shortening of the second image data address period within the second frame period; And
The 3D filter and the backlight unit such that the 3D filter is switched within the first and second blank periods, and the backlight unit is turned off within the first and second blank periods in synchronization with the switching of the 3D filter. And controlling the display device.

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