KR101681777B1 - Scanning backlight driving method and stereoscopic image display device using the same - Google Patents

Abstract

The present invention relates to a scanning backlight driving method and a stereoscopic image display apparatus using the same. According to another aspect of the present invention, there is provided a scanning backlight driving method comprising: dividing a backlight unit for irradiating light onto a display panel into a plurality of blocks; Dividing an input image into blocks and analyzing the gradation distribution of the input image for each block; Calculating a difference between a representative value for each block of the previous monocular image and a representative value for each block of another monocular image at present based on a result of analyzing the gradation distribution; Adjusting the backlight lighting timing according to a difference between a representative value of each block of the previous monocular image and a representative value of each block of the current monocular image; And generating a control signal for lighting the blocks at the backlight lighting timing adjusted for each block.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a scanning backlight driving method and a stereoscopic image display device using the same,

The present invention relates to a scanning backlight driving method and a stereoscopic image display apparatus using the same.

The stereoscopic display is divided into a stereoscopic technique and an autostereoscopic technique. The binocular parallax method uses parallax images of right and left eyes with large stereoscopic effect, and both glasses and non-glasses are used, and both methods are practically used. The glasses system displays polarized light of right and left parallax images on a direct-view type display device or a projector in a time-division manner. The glasses system implements a stereoscopic image using polarized glasses or liquid crystal shutter glasses. In the non-eyeglass system, an optical plate such as a parallax barrier or a lenticular lens is generally used to separate the optical axes of the left and right parallax images to realize a stereoscopic image.

The shutter glasses stereoscopic image display device displays the left eye image and the right eye image on a display panel in a time division manner. The glasses worn by the user include a left eye shutter that transmits light of the left eye image and a right eye shutter that transmits light of the right eye image. Therefore, the user sees only the left eye image during the odd frame, and only the right eye image is seen during the odd frame period, so that the user can feel the stereoscopic effect with the binocular parallax.

The stereoscopic image display device may be implemented using a liquid crystal display device. The liquid crystal display controls an electric field applied to the liquid crystal layer to modulate light incident from the backlight unit to display an image. In a liquid crystal display device implementing a stereoscopic image, the liquid crystal of the display panel has a slow response speed due to inherent characteristics such as viscosity and elasticity, as shown in Equations (1) and (2).

(gamma)는 액정분자의 회전점도(rotational viscosity)를 각각 의미한다. In Equation (1), τ _r denotes a rising time when a voltage is applied to the liquid crystal, V _a denotes an applied voltage, and V _F denotes a Freederick Transition Voltage ), D is the cell gap of the liquid crystal cell,

(gamma) means the rotational viscosity of the liquid crystal molecule, respectively.

In Equation (2), τ _f denotes a falling time at which the liquid crystal is restored to its original state due to the elastic restoring force after the voltage applied to the liquid crystal is turned off, and K denotes elastic modulus inherent to the liquid crystal.

As a method for solving the problem caused by the response speed of liquid crystal in a liquid crystal display device, a scanning backlight driving technique is known. The scanning backlight driving technique sequentially flashes the light sources of the backlight unit along the scan direction of the display line to provide an effect similar to the impulsive driving of a cathode ray tube (CRT).

In the case of a stereoscopic image display device in which left and right eye images are alternately displayed while driving at a high speed in a time division manner, a scanning backlight is used to improve the motion picture response time (MPRT) The right eye image is changed to the right eye image, or the right eye image is changed to the left eye image. However, in this case, the previous frame data and the next frame data, that is, the left eye and right eye images, or the right eye and left eye images may be mixed. Therefore, a motion blur which is a screen drag phenomenon, and a 3D crosstalk in which a left eye image and a right eye image overlap can occur.

An object of the present invention is to provide a scanning backlight driving method capable of improving motion blur and 3D crosstalk, and a stereoscopic image display apparatus using the same.

According to an aspect of the present invention, there is provided a scanning backlight driving method including dividing a backlight unit for irradiating light onto a display panel into a plurality of blocks; Dividing an input image into blocks and analyzing the gradation distribution of the input image for each block; Calculating a difference between a representative value for each block of the previous monocular image and a representative value for each block of another monocular image at present based on a result of analyzing the gradation distribution; Adjusting the backlight lighting timing according to a difference between a representative value of each block of the previous monocular image and a representative value of each block of the current monocular image; And generating a control signal for lighting the blocks at the backlight lighting timing adjusted for each block.

The stereoscopic image display apparatus of the present invention includes: a backlight unit that irradiates light to a display panel and is divided into a plurality of blocks; A gradation analyzer for dividing an input image into blocks and analyzing a gradation distribution of the input image for each block; A representative value calculation unit for extracting the representative value for each block based on a result of analyzing the gradation distribution and calculating a difference between a representative value of each block of the previous monocular image and a representative value of each block of another current monocular image; A scanning controller for adjusting a backlight lighting timing according to a difference between a representative value of each block of the previous monocular image and a representative value of each block of the current monocular image; And a backlight control unit for generating a control signal for lighting the blocks at the backlight lighting timing adjusted for each block.

The present invention analyzes the gradation distribution of pixel data for each scanning block, adjusts the backlight lighting timing according to the analyzed gradation distribution, and lights the light sources according to the adjusted backlight lighting timing. As a result, the present invention can improve the motion blur and the 3D crosstalk by turning on the light sources of the backlight unit in response to the response time of the liquid crystal.

1 is a perspective view showing a display panel and a backlight unit when a scanning backlight is driven.
2 is a waveform diagram showing a conventional scanning backlight driving in a stereoscopic image display apparatus.
3 is a flowchart illustrating a scanning backlight driving method of a stereoscopic image display apparatus according to an exemplary embodiment of the present invention.
4 is a waveform diagram illustrating scanning backlight driving of a stereoscopic image display apparatus according to an exemplary embodiment of the present invention.
5A to 5C are gradation distribution diagrams showing examples of various histogram analysis results.
6 is a block diagram illustrating a stereoscopic image display apparatus according to an exemplary embodiment of the present invention.
FIG. 7 is a block diagram showing the timing controller of FIG. 6 in detail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The component name used in the following description may be selected in consideration of easiness of specification, and may be different from the actual product name.

The present invention can be applied to a shutter glasses stereoscopic image display apparatus which time-divides a left eye image and a right eye image and separates light incident on a left eye and a right eye of a user through liquid crystal shutter glasses.

1 is a perspective view showing a display panel 10 and a backlight unit 20 when a scanning backlight is driven. The backlight unit 20 is divided and driven by M (M is a natural number of 2 or more) blocks. The backlight unit 20 of Fig. 1 is divided into five blocks BL1 to BL5 and driven. The input image of the display panel 10 is divided so as to correspond to each of the blocks BL1 to BL5 of the backlight unit 20. [

2 is a waveform diagram showing a conventional scanning backlight driving in a stereoscopic image display apparatus. Referring to FIG. 2, data (RGB _R , RGB _L ) of the right eye and left eye images are scanned from the first line (Line) to the L (L is a natural number) line of the display panel during one frame period. The display panel of Fig. 2 has 1080 vertical lines.

The display panel continuously displays the same right eye image data RGB _R for the 4N + 1 (N is a natural number) and the 4N + 2 frame periods and the same left eye image data (RGB _R ) for the (RGB _L ) continuously. Further, the gamma characteristics of continuous right eye image data RGB _R during the (4N + 1) th and (4N + 2) th frame periods are converted differently in units of one frame period, The gamma characteristic of the left eye image data RGB _L can be converted differently in units of one frame period.

Since the stereoscopic image display device operates at a high speed in time division, the frame frequency is multiplied by P (P is a natural number of 2 or more) times the input frame frequency. The frame frequency of FIG. 2 is multiplied by four times the input frame frequency. The input frame frequency is 50 Hz in the PAL (Phase Alternate Line) method and 60 Hz in the National Television Standards Committee (NTSC) method. One frame period is 5 msec when the frame frequency is 200 Hz, and one 4.16 msec is one frame period when the frame frequency is 240 Hz.

The blocks BL1 to BL5 of the backlight unit 20 are driven in order from the first block to the fifth block along the scan direction of the right eye and left eye image data RGB _R , RGB _L from the top of the display panel. The blocks BL1 to BL5 of the backlight unit 20 are sequentially driven after the liquid crystal response delay time of the right eye and left eye image data RGB _R , RGB _L has elapsed. 90% or more of the target luminance of the right eye and left eye image data (RGB _R , RGB _L ) of the pixel can be displayed after the liquid crystal response delay time of the display panel has elapsed. Therefore, the blocks BL1 to BL5 of the backlight unit 20 are turned on after the liquid crystal response delay time of the display panel has elapsed, and the blocks BL1 to BL5 of the backlight unit 20 are shifted from the left eye image to the right eye image , Or from the right eye image to the left eye image.

Each of the blocks BL1 to BL5 of the backlight unit 20 is driven by different backlight unit control signals C _BLU1 to C _{BLU5 in} scanning backlight driving. The first to fifth backlight unit control signals C _BLU1 to C _BLU5 sequentially turn on the blocks BL1 to BL5 of the backlight unit 20 after the liquid crystal response delay time of the display panel has elapsed.

Each of the blocks BL1 to BL5 of the backlight unit 20 is turned on at a constant PWM duty ratio every 8.33 ms. The PWM duty ratio is expressed by Equation (3).

In Equation 3, DR denotes a PWM duty ratio, d ₁ denotes a high logic level (backlight unit ON time) of the PWM signal, and d ₂ denotes a low logic level (backlight unit OFF time) of the PWM signal. The PWM duty ratio in Fig. 2 is approximately 18%, and the backlight unit lighting time d ₁ is approximately 1.49 ms.

The liquid crystal shutter glasses open the right eye or left eye shutter in synchronization with the section in which the blocks BL1 to BL5 of the backlight unit 20 are lit. When the right eye image data RGB _R is scanned on the display panel in synchronization with the section in which the blocks BL1 to BL5 of the backlight unit 20 are lit, the right eye shutter is opened and the left eye image data RGB _L is scanned , The left-eye shutter is opened.

2, when the blocks BL1 to BL5 of the backlight unit 20 are turned on in accordance with the section that is changed from the left eye image to the right eye image or from the right eye image to the left eye image, the left eye and right eye images, Images can be mixed. Therefore, there is a problem that motion blur and 3D crosstalk are generated.

3 is a flowchart illustrating a scanning backlight driving method of a stereoscopic image display apparatus according to an exemplary embodiment of the present invention. 4 is a waveform diagram illustrating scanning backlight driving of a stereoscopic image display apparatus according to an exemplary embodiment of the present invention. Referring to FIG. 3, the stereoscopic image display apparatus of the present invention analyzes a histogram for each block to extract a gray level representative value, and calculates a gray level representative value of a previous monaural image, And calculates the difference (? G _BL ) between representative values. Then, a scanning lighting timing for each block corresponding to the calculated? G _BL is selected, and the backlight unit is driven based on the backlight lighting timing. 3, the previous monocular image is the left eye image, and the current monocular image is the right eye image. A method of driving a stereoscopic image display apparatus according to an embodiment of the present invention will be described in detail with reference to FIG.

The stereoscopic image display apparatus of the present invention continuously displays the same right eye image data RGB _R for the 4N + 1 (N is a natural number) and the 4N + 2 frame periods, and the 4N + 3 and 4N + The same left eye image data (RGB _L ) is continuously displayed. Analyzes the right eye image data RGB _{R of} the 4N + 1 and 4N + 2 frame periods to scan and drive the backlight units block by block, and opens the right eye shutter ST _R of the liquid crystal shutter glasses. Accordingly, the first step determines whether RGB data (RGB _R ) of the right eye image is input. (S101)

The second step is to analyze the data of the input image to be displayed on the display panel corresponding to each of the blocks BL1 to BL5 of the backlight unit 20 when the right eye image data RGB _R is input. The analyzed histogram shows the gradation distribution of the input image to be displayed on the display panel for each of the blocks BL1 to BL5 of the backlight unit 20. [

5A to 5C are gradation distribution diagrams showing examples of various histogram analysis results. 5A to 5C, the X-axis represents the tone value and the Y-axis represents the number of data of the input image. When the right eye and left eye image data (RGB _R , RGB _L ) are 8 bits, the tone value is represented by G0 to G255. The luminance distribution of each gradation may be varied depending on whether the luminance distribution is concentrated in the low gradation region as shown in FIG. 5A, the luminance distribution is concentrated in the high gradation region as shown in FIG. 5B, or the luminance distribution is concentrated in the middle gradation region as shown in FIG. . (S102)

When the histogram analysis is completed, the third step extracts the block-specific grayscale representative values G _BL1 to G _BL5 . The block-specific gradation representative values (G _BL1 to G _BL5 ) can be calculated as a gradation value, a mode value, or an average value corresponding to the upper i% of the result of the histogram analysis. Here, i% may be specified as any value between 5% and 10%.

On the right side of FIG. 4, the variation _amounts of the block-specific gradation representative values (G _BL1 to G _BL5 ) are shown. Looking at the gray level represented by the block of the previous left-eye image value (G _BL1 ~ G _BL5), the gradation representative value of the first block (BL 1) (G _BL1) is the gradation representative value of G0, the second block (BL 2) (G The gradation representative value G _BL3 of the third block _BL3 is G150, the gradation representative value G _BL4 of the fourth block _BL4 is G70, the gradation representative value G _{BL2 of} the fourth block _BL4 is the gradation The representative value G _BL5 is G0. Looking at the current gradation representative value (G _BL1 ~ G _BL5) per block of the right-eye image, a first block gradation representative value of (BL 1) (G _BL1) is G50, the gradation representative value of the second block (BL 2) (G The gradation representative value G _BL3 of the third block _BL3 is G250 and the gradation representative value G _BL4 of the fourth block BL 4 is G70 and the gradation representative value G _{BL2 of} the fourth block _BL4 is the gradation The representative value (G _BL5 ) is G127. Here, the gray-scale representative values G _BL1 to G _{BL5 for} each block represent the gray-scale representative values of the data of the input image corresponding to the blocks BL1 to BL5 of the backlight unit 20, respectively. (S103)

The fourth step calculates the difference (? G _BL1 to? G _BL5 ) between the gradation representative value of each block in the previous left eye image and the representative gradation value of each block in the current right eye image. In Figure 4, when calculating the difference between specific gradation representative value of the block (ΔG _BL1 ~ ΔG _BL5), the first block (BL 1) difference (ΔG _BL1) of a gradation representative value of the G50, the second block (BL 2) The difference (? _BL2 ) of the gradation representative values is G200, the difference? GRBL3 of the gradation representative values of the third block ( _BL3 ) is G100, and the difference? GRBL4 of the gradation representative values of the fourth block ( _BL4 ) G70, and the difference (? _BL5 ) between gradation representative values of the fifth block ( _BL5 ) is G127. (S104)

The backlight lighting timing (T _ON1 to T _ON5 ) for each block is selected corresponding to the difference (? _BL1 to? _BL5 ) of the calculated gray-scale representative values for each block. The calculated difference (? G _BL1 to? G _BL5 ) of gradation representative values for each block and the backlight lighting timing (T _ON1 to T _ON5 ) for each block can be stored in a register or a memory of a table type . The backlight lighting timing (T _ON1 to T _ON5 ) for each block corresponding to the difference (? G _BL1 to? G _BL5 ) of the calculated gradation representative values for each block can be determined through a preliminary experiment.

Ido lit backlight block-by-block via a fourth timing (T _ON1 ~ T _ON5) to look at in detail, the first block because of the difference (ΔG _BL1) is G50 of (BL 1), the response delay of the liquid crystal in the first block (BL 1) small. Therefore, it is predicted that the time at which the data of the input image reaches the target luminance is accelerated, and the backlight lighting timing (T _ON1 ) of the first block (BL 1) is shifted forward.

Since the difference? _{BL2 in} the second block BL1 is G200, the response delay of the liquid crystal in the second block _BL2 is large. Therefore, the timing at which the pixel data reaches the target luminance will not be accelerated, and the backlight lighting timing (T _ON2 ) of the second block (BL 2) is a section that is changed from the right eye image to the left eye image.

Since the difference? _{BL3 in} the third block _BL3 is G100, the response delay of the liquid crystal in the third block _BL3 is small. Therefore, the time point at which the pixel data reaches the target luminance is predicted to be accelerated, and the backlight lighting timing _TON3 of the third block _BL3 is also shifted forward.

Since the difference? _{BL4 in} the fourth block _BL4 is G70, the response delay of the liquid crystal in the fourth block _BL4 is small. Therefore, the time at which the pixel data reaches the target luminance is predicted to be accelerated, and the backlight lighting timing (T _ON4 ) of the fourth block ( _BL4 ) is also shifted forward.

Since the difference? _{BL5 in} the fifth block _BL5 is G127, the response delay of the liquid crystal in the fifth block _BL5 is small. Therefore, the time when the pixel data reaches the target luminance is predicted to be accelerated, and the backlight lighting timing (T _ON5 ) of the fifth block ( _BL5 ) is also shifted forward.

As a result, since the response delay of the liquid crystal is short in the first block BL 1, the third block BL 3, the fourth block BL 4, and the fifth block BL 5, the right eye image is changed to the left eye image It does not need to be lit in accordance with the interval. However, since the response delay of the liquid crystal is large in the second block (BL 2), the second block (BL 2) is lit in accordance with the section which is changed from the right eye image to the left eye image.

Further, the smaller the difference (? G _BL1 to? G _BL5 ) of the gradation representative values for each block, the more the backlight lighting timings (T _ON1 to T _ON5 ) are shifted further. Since the response delay time of the liquid crystal is reduced as the difference (? _BL1 to? _BL5 ) of the gray-scale representative values for each block is smaller, the data of the input image of each of the blocks BL1 to BL5 of the backlight unit 20 The target luminance can be reached.

Furthermore, the blocks BL1 to BL5 of the backlight unit 20 may not be sequentially implemented. As shown in Figure 4, the second block (BL 2) gray-scale difference between the representative value (ΔG _BL2) is large, a third block (Block) gray-scale difference between the representative value (ΔG _BL3) is less, and the third block of the (BL The backlight lighting timing (T _ON3 ) of the second block (BL 2) is pulled in the future, but the backlight lighting timing (T _ON2 ) of the second block (BL 2) is the section changing from the right eye image to the left eye image.

On the other hand, since the lighting duration d ₁ of each of the blocks BL1 to BL5 of the backlight unit 20 is the same, each of the blocks BL1 to BL5 of the backlight unit 20 is lit for the same time. However, since the backlight lighting timings (T _ON1 to T _ON5 ) vary in accordance with the difference (? _BL1 to? _BL5 ) of the gray scale representative values, the turn-off duration time (d ₂ ) and the PWM duty ratio of each of the blocks are changed.

The present invention shifts the timing (T _ON1 to T _ON5 ) of the block-by-block scanning illumination forward as the difference (? G _BL1 to? G _BL5 ) And the resulting motion blur and 3D crosstalk can be minimized. (S105)

The backlight unit is scanned and driven based on the backlight lighting timing (T _ON ) for each selected block. In addition, the right-eye shutter of the liquid crystal shutter glasses is opened in synchronization with the lighting periods of the blocks BL1 to BL5 of the backlight unit 20. [ (S106)

The 4N + 3, and the 4N + 4 is driven by the scanning block the light unit analyzes the left-eye image data (RGB _L) of the frame period, and opening the left-eye shutter _(L ST) of the liquid crystal shutter glasses. When the left eye image data RGB _L is input, the scanning backlight driving method of the stereoscopic image display device according to the present invention is the same as the right eye image data RGB _R (S101 through S106).

6 is a block diagram illustrating a stereoscopic image display apparatus according to an exemplary embodiment of the present invention. 6, the liquid crystal display of the present invention includes a display panel 10, a backlight unit 20, a liquid crystal shutter glasses 30, a display panel driving unit 110, a backlight driving unit 120, A backlight control unit 150, a timing controller 160, and a system board 170. The liquid crystal shutter glasses control signal transmission unit 140 includes a receiving unit 130, a liquid crystal shutter glasses control signal transmitting unit 140,

The display panel 10 alternately displays the left eye image data RGB _L and the right eye image data RGB _R under the control of the timing controller 160. The display panel 10 may display two-dimensional image data (RGB) having no distinction between the left eye image and the right eye image under the control of the timing controller 160. [ The display panel 10 may be selected as a hold-type display element requiring the backlight unit 20. [ The hold-type display device is typically a transmissive liquid crystal display panel that modulates light from the backlight unit 20.

The transmissive liquid crystal display panel includes a thin film transistor (hereinafter referred to as "TFT") substrate and a color filter substrate. A liquid crystal layer is formed between the TFT substrate and the color filter substrate. On the TFT substrate, data lines and gate lines (or scan lines) are formed to intersect each other on a lower glass substrate, and liquid crystal cells are arranged in a matrix form in cell regions defined by data lines and gate lines do. The TFT formed at the intersection of the data lines and the gate lines transmits a data voltage supplied to the pixel electrode of the liquid crystal cell via the data lines in response to a scan pulse from the gate line. To this end, the gate electrode of the TFT is connected to the gate line, and the source electrode is connected to the data line. The drain electrode of the TFT is connected to the pixel electrode of the liquid crystal cell. A common voltage is supplied to the common electrode facing the pixel electrode. The color filter substrate includes a black matrix and a color filter formed on the upper glass substrate. The common electrode is formed on the upper glass substrate in a vertical electric 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 lower glass substrate together with the pixel electrode in the driving method. In each of the upper glass substrate and the lower glass substrate of the transmissive liquid crystal display panel, a polarizing plate is attached and an alignment film for setting a pre-tilt angle of the liquid crystal is formed. A spacer for maintaining a cell gap of the liquid crystal layer is formed between the upper glass substrate and the lower glass substrate of the transmissive liquid crystal display panel. The liquid crystal mode of the transmissive liquid crystal display panel can be implemented not only in the TN mode, the VA mode, the IPS mode, and the FFS mode, but also in any liquid crystal mode.

The display panel driving unit 110 includes a data driving circuit and a gate driving circuit. The data driving circuit converts the data (RGB _L , RGB _R ) of the left eye image and the right eye image inputted from the timing controller 160 in the three-dimensional image into the positive / negative gamma compensation voltage, Voltages. The positive / negative polarity analog data voltages output from the data driving circuit are supplied to the data lines of the display panel 10. The gate driving circuit sequentially supplies gate pulses (or scan pulses) synchronized with the data voltage to the gate lines of the display panel 10. [

The backlight unit 20 illuminates the display panel 10 for a predetermined period of time, and extinguishes the light for another period. The backlight unit 20 includes a light source, a light guide plate (or diffusion plate), and a plurality of optical sheets that are turned on in accordance with the driving power supplied from the backlight driving unit 120. The backlight unit 20 may be implemented as a direct type backlight unit or an edge type backlight unit. The light sources of the backlight unit 20 include any one of a light source of a HCFL (Cold Cathode Fluorescent Lamp), a CCFL (Cold Cathode Fluorescent Lamp), an EEFL (External Electrode Fluorescent Lamp) can do.

The backlight unit 20 may be divided into M blocks. 6, the backlight unit 20 is divided into five blocks BL1 to BL5. The display panel 10 may also be divided into M blocks corresponding to the backlight unit 20. [ This is because, when the backlight unit 20 is scanned and driven, the backlight lighting timing (T _ON ) is selected by analyzing pixel data of each block of the display panel 10 as a histogram.

The backlight driving unit 120 generates driving power for lighting the backlight unit 20 light sources. The backlight driver 120 periodically turns on / off the driving power supplied to the light sources under the control of the backlight controller 150. The backlight driving unit 120 receives a backlight control signal C _{BLU for} controlling the blocks BL1 to BL5 of the backlight unit 20 and applies driving power to each of the blocks BL1 to BL5 of the backlight unit 20. [ .

The liquid crystal shutter glasses 30 are provided with an electrically controlled left eye shutter ST _L and a right eye shutter ST _R. Each of the left eye shutter ST _L and the right eye shutter ST _R includes a first transparent substrate, a first transparent electrode formed on the first transparent substrate, a second transparent substrate, a second transparent electrode formed on the second transparent substrate, And a liquid crystal layer sandwiched between the first and second transparent substrates. A reference voltage is supplied to the first transparent electrode and an ON / OFF voltage is supplied to the second transparent electrode. Each of the left eye shutter ST _L and the right eye shutter ST _R transmits the light from the display panel 10 when the ON voltage is supplied to the second transparent electrode while when the OFF voltage is supplied to the second transparent electrode And blocks light from the display panel 10.

The liquid crystal shutter glasses control signal transmitting unit 140 is connected to the timing controller 160 and transmits the liquid crystal shutter glasses control signal C _ST inputted from the timing controller 160 to the liquid crystal shutter glasses control signal receiving unit 130 . The liquid crystal shutter glasses control signal receiving unit 130 is installed in the liquid crystal shutter glasses 30 and receives the liquid crystal shutter control signal C _ST through the wireless interface and outputs the liquid crystal shutter control signal C _ST in accordance with the liquid crystal shutter control signal C _ST . (ST _L ) and the right-eye shutter (ST _R ) of the shutter unit 30 are alternately opened and closed.

When the liquid crystal shutter control signal C _ST is input to the liquid crystal shutter control signal receiving unit 130 with the first logic value, the ON voltage is supplied to the second transparent electrode of the left eye shutter ST _L , while the right eye shutter ST _R is supplied with an OFF voltage. When the liquid crystal shutter control signal C _ST is input to the liquid crystal shutter control signal receiving unit 130 with the second logic value, the OFF voltage is supplied to the second transparent electrode of the left eye shutter ST _L while the right eye shutter ST _R ) is supplied with the ON voltage. Therefore, the left eye shutter ST _L of the liquid crystal shutter glasses 30 is opened when the liquid crystal shutter control signal C _ST is generated as the first logical value, and the right eye shutter ST _R of the liquid crystal shutter glasses 30 is opened And is opened when the liquid crystal shutter control signal C _ST is generated as the second logic value. The first logic value may be set to a High logic voltage, and the second logic value may be set to a High logic voltage.

The display panel control signal C _DIS includes a data control signal for controlling the operation timing of the data driving circuit and a gate control signal for controlling the operation timing of the gate driving circuit. The data control signal includes a source start pulse (SSP), a source sampling clock (SSC), a source output enable (SOE) signal, a polarity control signal (POL) The source start pulse SSP controls the data sampling start timing of the data driving circuit. The source sampling clock is a clock signal that controls the sampling operation of the data driving circuit based on the rising or falling edge. The source start pulse SSP and the source sampling clock SSC may be omitted if the digital video data to be input to the data driving circuit is transmitted in the mini LVDS (Low Voltage Differential Signaling) interface standard. The polarity control signal POL inverts the polarity of the data voltage output from the data driving circuit to L (L is a positive integer) horizontal period period. The source output enable signal SOE controls the output timing of the data driving circuit.

The gate control signal includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal (GOE), and the like. The gate start pulse (GSP) controls the timing of the first gate pulse. The gate shift clock GSC is a clock signal for shifting the gate start pulse GSP. The gate output enable signal GOE controls the output timing of the gate drive circuit.

A backlight control unit 150 receives the information about the backlight lighting timing by block (T _ON) from the timing controller 160, the blocks of the backlight unit (20) (BL1 ~ BL5), each of the backlight control signal (C _BLU) To the backlight driver (120). The backlight control signal C _BLU controls the backlight driver 120 so that the blocks BL1 to BL5 of the backlight unit 20 are periodically turned on and off. A detailed description thereof will be given later with reference to FIG.

The system board 170 converts the resolution of the image data RGB input from the outside into the resolution of the display panel 10 and outputs various timing signals Vsync, Hsync, DE, CLK, Lt; / RTI >

7 is a block diagram showing the timing controller 160 of FIG. 6 in detail. Referring to FIG. 7, the timing controller 160 of the present invention includes a gradation analysis unit 161, a representative value calculation unit 162, a scanning control unit 163, and a register 164.

The gray level analyzer 161 receives RGB data from the system board 170 and analyzes the gray level distribution of data of the input image of each of the blocks BL1 to BL5 of the backlight unit 20. [ The tone values of the data of the input image may be represented by the luminance information Y calculated using the R data, the G data, and the B data as variables. The gradation distribution of the data of the input image analyzed through the gradation analysis unit 161 may take various forms including the shapes of FIGS. 5A to 5C.

The representative value calculation unit 162 extracts the gradation representative value G _BL from the gradation distribution analyzed through the gradation analysis unit 161. The block-specific grayscale representative value G _BL can be extracted as a grayscale value, a mode value, or an average value corresponding to the upper i% of the histogram analysis result. Here, i% may be specified as any value between 5% and 10%.

A representative value calculation unit 162 calculates the difference between the previous monocular image block by the gradation representative value and the current another monocular image gradation representative value of each block of the (ΔG _BL) from the gradation representative value (G _BL) extraction. Accordingly, the representative value calculation unit 162 may include a memory for storing the gray scale representative values of the previous monocular images. The representative value calculation unit 162 outputs to the scanning control unit 163 the difference (ΔG _BL ) between the representative gray level representative value of the previous monocular image and the current gray level representative value of another monocular image.

Further, the scanning control unit 163 stores the difference (ΔG _BL ) between the representative gradation value of the previous monocular image of the previous monocular image input from the representative value calculation unit 162 and the representative gradation value of each monocular image of another current monocular image, ). Register 164 is a memory for storing the previous monocular image block by the gradation representative value and the difference between the current another monocular image gradation representative value of each block of the (ΔG _BL) and the backlight lighting timing by block (T _ON) in table form to be.

The register 164 receives the difference (ΔG _BL ) between the representative gradation value of the previous monocular image for each block and the representative gradation value of another monocular image of the current one, and calculates the backlight lighting timing (T _ON ). The number may be implemented in a number equal to that of the blocks of the backlight unit (20) (BL1 ~ BL5) , in this case the difference (ΔG _BL) of a gradation representative value of the first block of the register 164 is the first register And the difference (? G _BL ) of the gradation representative values of the second block is input to the second register. The scanning control unit 163 outputs the backlight lighting timing (T _ON ) for each block inputted from the register 164 to the backlight control unit 150. [

The backlight control unit 150 receives the backlight lighting timing (T _ON ) for each block from the scanning control unit 163. The backlight control unit 150 generates a vertical synchronization signal Vsync or a gate start pulse GSP based on a horizontal synchronization signal Hsync or a data enable signal DE, A signal in which a pulse is generated once in one frame period (one vertical period) can be input from the timing controller 160 as shown in FIG. The backlight control unit 150 determines the backlight lighting timing (T _ON ) for each block through the various timing signals and _supplies backlight control signals C _BLU1 to C _BLU5 for each block adjusted in timing to the backlight driver 120). The backlight driving unit 120 supplies driving power to each of the blocks BL1 to BL5 of the backlight unit 20 according to the backlight control signal C _BLU received from the backlight control unit 150. [

The timing controller 160 includes a backlight lighting timing (T _ON), and the blocks of the backlight unit 20 from the various timing signals (BL1 ~ BL5), the liquid crystal shutter glasses control signal (C such that the liquid crystal shutter glasses open in synchronization with the lighting period of the _ST ) to the liquid crystal shutter glasses control signal transmission unit 140. [ The liquid crystal shutter glasses control signal C _ST is transmitted to the liquid crystal shutter eyeglass control signal receiving unit 130 so that the left eye shutter ST _L and the right eye shutter ST _{R of the} liquid crystal shutter glasses 30 are synchronized with the lighting periods of the blocks Open and close.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the present invention should not be limited to the details described in the detailed description, but should be defined by the claims.

10: display panel 20: backlight unit
30: liquid crystal shutter glasses 110: display panel driver
120: backlight driving unit 130: liquid crystal shutter glasses control signal receiving unit
140: liquid crystal shutter glasses control signal transmission unit 150: backlight control unit
160: Timing controller 161:
162: Representative value calculation unit 163: Scanning control unit
164: Register 170: System board

Claims (13)

Dividing a backlight unit for illuminating the display panel into a plurality of blocks;
Dividing an input image into blocks and analyzing the gradation distribution of the input image for each block;
Calculating a difference between a representative value for each block of the previous monocular image and a representative value for each block of another monocular image at present based on a result of analyzing the gradation distribution;
Adjusting the backlight lighting timing according to a difference between a representative value of each block of the previous monocular image and a representative value of each block of the current monocular image; And
And generating a control signal for lighting the blocks at the backlight lighting timing adjusted for each block,
The backlight turn-
Wherein the difference between a representative value of each block of the previous monocular image and a representative value of each block of another monocular image is shifted further. The method according to claim 1,
Further comprising opening the liquid crystal shutter glasses for opening the right eye shutter when the display panel displays the right eye image and opening the left eye shutter when displaying the left eye image in synchronization with the lighting duration of the blocks, Way. The method according to claim 1,
The turn-on duration of the blocks may be determined,
Wherein the predetermined number of blocks is set to be the same for each of the blocks. delete The method according to claim 1,
Wherein the backlight lighting timing is adjusted to a time after the response delay time of the liquid crystal. The method according to claim 1,
And lighting the blocks in accordance with the control signal. A backlight unit that illuminates the display panel with light and is divided into a plurality of blocks;
A gradation analyzer for dividing an input image into blocks and analyzing a gradation distribution of the input image for each block;
A representative value calculation unit for extracting the representative value for each block based on a result of analyzing the gradation distribution and calculating a difference between a representative value of each block of the previous monocular image and a representative value of each block of another current monocular image;
A scanning controller for adjusting a backlight lighting timing according to a difference between a representative value of each block of the previous monocular image and a representative value of each block of the current monocular image; And
And a backlight control unit for generating a control signal for lighting the blocks at the backlight lighting timing adjusted for each block,
Wherein the backlight lighting timing is shifted further as the difference between the representative value of each block of the calculated previous monocular image and the representative value of each block of the current monocular image is smaller. 8. The method of claim 7,
Wherein the lighting duration of the blocks is set to be the same for each of the blocks. 8. The method of claim 7,
Further comprising a liquid crystal shutter eyeglass that opens the right eye shutter when the display panel displays the right eye image and opens the left eye shutter when displaying the left eye image,
Wherein the liquid crystal shutter glasses are opened in synchronization with a lighting duration time of the blocks. delete 8. The method of claim 7,
Wherein the backlight lighting timing is adjusted to a time after the response delay time of the liquid crystal. 8. The method of claim 7,
And a backlight driver for lighting the blocks according to the control signal. 8. The method of claim 7,
The scanning control unit,
And a register for storing a difference between a representative value of each block of the previous monocular image calculated for each block and a representative value of each block of the current monocular image and a timing of lighting the backlight.

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