KR20120007863A - Data modulation method and stereoscopic image display device using the same - Google Patents

Abstract

PURPOSE: A data modulation method and a stereoscopic image display device using the same are provided to minimize the black luminance by optimizing white luminance using low under driving and optimizing black luminance using a high under driving. CONSTITUTION: If the gradation of current frame data is higher than that of a previous frame data, the current frame data is modulated in an over driving modulation ratio(S102). If the gradation of the previous frame data and the gradation of the current frame data are same, the current frame data is outputted without change(S104). If the gradation of current frame data is lower than that of the previous frame data, the current frame data is modulated in an under driving modulation ratio(S106). The under driving modulation ratio is higher than that of the overdriving modulation ratio rate.

Description

DATA MODULATION METHOD AND STEREOSCOPIC IMAGE DISPLAY DEVICE USING THE SAME}

The present invention relates to a data modulation method and a stereoscopic image display apparatus using the same.

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 the left and right eyes with a large stereoscopic effect, and there are glasses and no glasses, both of which are put to practical use. In the spectacle method, the polarization of the left and right parallax images is displayed on the direct view display device or the projector or displayed in a time division method. The glasses method implements a stereoscopic image using polarized glasses or liquid crystal shutter glasses. In the autostereoscopic method, an optical plate such as a parallax barrier and a lenticular lens is generally used to realize a stereoscopic image by separating an optical axis of a parallax image.

In a liquid crystal display device implementing a stereoscopic image, the liquid crystal of the display panel has a slow response time due to intrinsic viscosity, elasticity, and the like, as shown in Equations 1 and 2.

(gamma)는 액정분자의 회전점도(rotational viscosity)를 각각 의미한다.Where τ _r is the rising time when voltage is applied to the liquid crystal, V _a is the applied voltage, and V _F is the Freederick Transition Voltage at which the liquid crystal molecules begin their inclined motion. d is the cell gap of the liquid crystal cell,

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

Here, τ _f denotes a falling time during which the liquid crystal is restored to its original position by the elastic restoring force after the voltage applied to the liquid crystal is turned off, and K denotes the elastic modulus inherent to the liquid crystal.

An overdriving method is known as a method for improving the response speed of a liquid crystal in a liquid crystal display. The existing overdrive modulation method is to improve a motion blur, a screen drag phenomenon of a 2D image. However, 3D crosstalk, which is a problem in three-dimensional images, is a phenomenon in which a left eye image and a right eye image overlap, and motion blueer and 3D crosstalk have different concepts. Therefore, unlike a 2D image, an optimized data modulation method for improving 3D crosstalk in a 3D image is required.

An object of the present invention is to provide a data modulation method capable of improving 3D crosstalk and a stereoscopic image display apparatus using the same.

In order to achieve the above object, the data modulation method of the present invention comprises the steps of: data-modulating the current frame data within a predetermined overdriving modulation ratio when the grayscale of the current frame data is greater than the grayscale of previous frame data; Outputting the current frame data as it is when the gray level of the previous frame data and the gray level of the current frame data are the same; And outputting the data by modulating the current frame data within a predetermined underdriving modulation ratio when the gradation of the current frame data is smaller than that of the previous frame data, wherein the underdriving modulation ratio is the overdriving modulation. It is characterized by higher than the ratio.

When the gradation of the current frame data is greater than the gradation of the previous frame data, the stereoscopic image display device modulates and outputs the current frame data within a predetermined overdriving modulation ratio, and outputs the gradation of the previous frame data and the current. When the gray level of the frame data is the same, the current frame data is output as it is, and when the gray level of the current frame data is smaller than the gray level of the previous frame data, the current frame data is modulated and output within the predetermined underdriving modulation ratio. A data modulator; And a controller for supplying left and right eye image data modulated by the data modulator to a display panel, wherein the underdriving modulation ratio is higher than the overdriving modulation ratio.

The present invention compares previous frame data with current frame data, and performs weak overdriving modulation when the current frame data is large, and performs strong underdriving modulation when the current frame data is small. As a result, the present invention can optimize the white brightness using the weak over-driving, and minimize the black brightness by using the strong under driving. In addition, the present invention can improve 3D crosstalk by optimizing white brightness and minimizing black brightness.

1 is a view illustrating an operation principle of a shutter glasses type stereoscopic image display device.
2 is a view illustrating an operation principle of a polarizing glasses type stereoscopic image display device.
3 is a graph showing the response delay of the liquid crystal in the 3D mode.
4 is a diagram illustrating an image in which 3D crosstalk is displayed.
5 is a graph showing the response curve of the liquid crystal having improved 3D crosstalk.
6 is a flowchart illustrating a data modulation method according to an embodiment of the present invention.
7 is a view illustrating a data modulation method according to an embodiment of the present invention with a look-up table.
8 is a table showing experimental values comparing the 3D crosstalk ratio of the conventional overdrive modulation method and the data modulation method of the present invention.
9 is a block diagram illustrating a stereoscopic image display device according to an exemplary embodiment of the present invention.
FIG. 10 is a detailed block diagram illustrating the data modulator of FIG. 9.

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 numbers refer to like elements throughout. In the following description, when it is determined that a detailed description of known functions or configurations related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Component names used in the following description may be selected in consideration of ease of specification, and may be different from actual product part names.

The present invention can be applied to a spectacle type stereoscopic image display device that separates light incident to the left and right eyes of a user through glasses.

1 is a view illustrating an operation principle of a shutter glasses type stereoscopic image display device. Referring to FIG. 1, a portion indicated in black in the shutter glasses SG is a shutter that blocks light traveling toward an observer, and a portion indicated in white refers to a shutter that transmits light toward the observer.

The left eye image data RGB _L is written in the display panel DIS during the odd frame frame in the 3D mode, and the left eye shutter ST _L of the shutter glasses SG is opened. During the even frame period of the 3D mode, the right eye image data RGB _R is written in the display panel DIS and the right eye shutter ST _R of the shutter glasses SG is opened. The left eye shutter ST _L and the right eye shutter ST _R of the shutter glasses SG are electrically controlled through the wired / wireless interface to synchronize with the display panel DIS. Therefore, the observer sees only the left eye image with his left eye during the radix frame, and only the right eye image with his right eye during the excellent frame period so that the viewer can feel a three-dimensional effect with binocular disparity.

2 is a view illustrating an operation principle of a polarizing glasses type stereoscopic image display device. Referring to FIG. 2, the display panel DIS displays the left eye image data RGB _L during the odd frame period and the right eye image data RGB _R during the even frame period in the 3D mode. An active retarder (AR) is installed on the display panel DIS to convert the polarization characteristics of the left eye image and the polarization characteristics of the right eye image differently.

The light of the left eye image and the right eye image that is time-divisionally displayed on the display panel DIS is converted into a specific polarized light, for example, left polarized light, through the polarizing plate of the display element and is incident on the active retarder AR. The active retarder AR is synchronized with the display element DIS. When the left eye image is displayed on the display panel DIS, the active retarder AR passes the light without changing the polarization characteristic of the light incident from the display panel DIS. In contrast, when the right eye image is displayed on the display panel DIS, the active retarder AR converts the polarization characteristic of the light incident from the display panel DIS into another polarized light, for example, postal light. The active retarder AR may be implemented as a liquid crystal panel in a twisted nematic (TN) mode including a common electrode and a plurality of scan electrodes facing each other with a liquid crystal layer interposed therebetween, and without a polarizer, a color filter, and a black matrix. The active retarder AR transmits incident light as it is when the Von voltage is applied to the scan electrodes, and phases the incident light by λ (λ is the wavelength of light) / 2 when the Voff voltage is applied to the scan electrodes. By delaying, the polarization characteristic of the incident light can be converted.

The polarizing glasses PG include a left eye filter F _L that passes only light of the left polarized light and a right eye filter F _R that passes only light of postal light. Therefore, the observer sees only the left eye image with his left eye during the radix frame, and only the right eye image with his right eye during the excellent frame period, so that the viewer can feel a three-dimensional effect with binocular disparity.

Meanwhile, the display panel DIS of FIGS. 1 and 2 may display a 2D planar image in the 2D mode, and may display a 3D image in which the left eye image and the right eye image are time-divided in the 3D mode. However, in the 3D image display device which displays the left eye image and the right eye image by time division or spatial division and drives the high speed, 3D crosstalk may occur due to the response delay of the liquid crystal.

3 is a graph showing the response delay of the liquid crystal in the 3D mode. 4 is a diagram illustrating an image in which 3D crosstalk is displayed. 5 is a graph showing the response curve of the liquid crystal having improved 3D crosstalk. A method of improving 3D crosstalk will be described with reference to FIGS. 3 to 5.

Referring to FIG. 3, left eye image data RGB _L is input during an N-1 (N is a natural number of 2 or more) frame period, and right eye image data RGB _R is input during an Nth frame period. In order to measure 3D crosstalk, data of black luminance is input to the left eye image data RGB _L , and data of white luminance is input to the right eye image data RGB _R. The backlight unit is driven to turn off at the same time as the N-th and N-th frame periods are finished in consideration of the response delay time of the liquid crystal. In addition, since the backlight unit is driven at a constant duty ratio, the lighting duration of the backlight unit is the same every frame.

Since the user can watch the image while the white luminance data is input, in FIG. 3, 3D crosstalk is measured based on the right eye image, and thus only the right eye shutter ST _R is opened and measured. 3D crosstalk is the same as Equation 3.

In Equation 3, 3D CT (%) is 3D crosstalk ratio (%), C _{Black Luminance} is the current black luminance, T _{Black Luminance} is the target black luminance, C _{White Luminance} means the current white luminance.

Referring to part A of FIG. 3, left eye image data (RGB)_L) Is the peak black luminance (T) due to the response delay of the liquid crystal._{Black Luminance}), And peak black luminance (T_{Black Luminance}Luminance higher than_{Black Luminance}). Therefore, as shown in part C of FIG. 4, a problem in which the left eye image to be invisible in the right eye image is blurred.

Referring to part B of FIG. 3, the peak white luminance T _White to be represented by the right eye image data RGB _R due to the response delay of the liquid crystal. _Luminance ) cannot be expressed and peak white luminance (T _{White) Luminance} lower than luminance (C _{White Luminance} ). As a result, the luminance becomes peak white luminance (T _{White). Luminance} ) (Target) can not be raised, the problem looks darker than the original image.

As a result, in order to reduce the crosstalk ratio, the numerator of Equation 3 must be made smaller or the denominator is increased. Left eye image data (RGB _L ) is peak black luminance (T _{Black) The} closer to _Luminance ), the smaller the numerator in Equation 3. Right eye image data (RGB _R ) is peak white luminance (T _{White) The} closer to _Luminance ), the larger the denominator of Equation 3.

Referring to FIG. 5, the response curve (a) of the conventional liquid crystal, the response curve (b) of the improved liquid crystal, the peak white luminance (c), the peak black luminance (d), and the downward direction The adjusted peak white luminance e is shown. In FIG. 5, left eye image data RGB _L is input during an N-th frame period, and right eye image data RGB _R is input during an N-th frame period. The left eye image data RGB _L is input with black luminance data, and the right eye image data RGB _R is input with white luminance data.

The response curve (a) of the conventional liquid crystal does not express both the peak white luminance (c) and the peak black luminance (d), which causes 3D crosstalk. The response curve (b) of the improved liquid crystal does not represent peak white luminance (c) but represents peak black luminance (d). In order to enable the improved response curve b of the liquid crystal to represent the peak white luminance c, the peak white luminance c is adjusted downward. Here, the peak white luminance c may be adjusted downward in consideration of the response characteristic of the liquid crystal.

The downwardly adjusted peak white luminance e is set to a luminance lower than the peak white luminance c. Therefore, as compared with the response curve (b) and the peak white luminance (c) of the improved liquid crystal, the difference between the response curve (b) and the downwardly adjusted peak white luminance (e) of the improved liquid crystal is much reduced. As a result, the response curve of the liquid crystal is corrected from the response curve (a) of the existing liquid crystal to the improved response curve (b) of the liquid crystal, and the peak white luminance (c) is adjusted downward by the downwardly adjusted peak white luminance (e). 3D crosstalk can be significantly improved. The concept of the present invention for improving 3D crosstalk is as follows.

First, the response curve (a) of the existing liquid crystal is corrected to the response curve (b) of the improved liquid crystal. When the N-th frame F _N data is smaller than the N-th frame F _{N -1} data, the N-th frame F _N data is an underdriven modulation value so that the peak black luminance d can be expressed. Is modulated.

Secondly, the peak white luminance c is adjusted downward to the downwardly adjusted peak white luminance e. The luminance from the peak black luminance d to the peak white luminance c is expressed by dividing by 2 ⁿ corresponding to the number of gray levels of the data. Therefore, the number of gray scales that can be expressed when the data (RGB _L , RGB _R ) of the input left eye or right eye image is n bits is 2 ⁿ . For example, when the data (RGB _L , RGB _R ) of a left or right eye image is 8 bits, 2 ⁸ = 256 gray levels, that is, 256 grays of G0 to G255 are represented. However, since the peak white luminance c is downwardly adjusted, the luminance from the peak black luminance d to the downwardly adjusted peak white luminance e is represented by 256 gray levels of G0 to G255.

Hereinafter, a data modulation method according to an embodiment of the present invention will be described with reference to FIGS. 6 to 8. 6 is a flowchart illustrating a data modulation method according to an embodiment of the present invention. First, the data modulation method according to the embodiment of the present invention satisfies Equations 4 to 6.

First, when the data value input to the same pixel of the display panel is larger in the N _- th frame F _N than in the N _- th frame F _N-1 , the input data value is larger than the N-th frame F _N data. It is set to a larger 'weak overdriving modulation value'. Here, the about overdriving modulation value means a modulation value overdriving modulation at a modulation rate of 0% to 10%. For example, the 10% overdriving modulation ratio means to modulate a data value input to the N-th frame F _N into a modulation value corresponding to a luminance as high as 10% of the target luminance of the data value. (S101, S102)

Second, the data value input to the same pixel of a display panel is the frame N-1 _(N F _-1), and if they are identical in the N-th frame (F _N) is set to a value equal to the N-th frame (F _N) . That is, the data value input to the Nth frame F _N is output as it is without being modulated. (S103, S104)

Thirdly, when the smaller value from the data input to the same pixel of a display panel is the frame N-1 _(N F _-1) than the N-th frame (F _N), the input data value of the N-th frame (F _N It is set to a 'strong under driving modulation value' which is smaller than. (See Equation 6) The strong underdriving modulation value refers to a modulation value underdriving modulated at a modulation rate of 20% to 50%. For example, the 30% under-driving modulation ratio means to modulate a data value input to the N-th frame F _N into a modulation value corresponding to luminance lower by 30% of the target luminance of the data value. (S105, S106)

Here, when the input data of the left or right eye image (RGB _L , RGB _R ) is 8 bits, the luminance from the peak black luminance d to the adjusted peak white luminance e is adjusted to 256 gray levels of G0 to G255. The target luminance is a luminance value corresponding to the gray level of the input data.

After all, the present invention, if a data value of the frame N-1 _(N F _-1) the N-th frame (F _N) of data is larger than the data about modulated over-driving, the frame N-1 _(N F _-1) data If the N-th frame F _N is smaller than the data, the strong underdriving modulation is performed. That is, overdriving modulation and underdriving modulation are data modulated at different rates. Since the present invention improves 3D crosstalk by adjusting the polling of the response curve of the liquid crystal to minimize black brightness, the underdriving ratio is higher than the overdriving ratio.

7 is a view illustrating a data modulation method according to an embodiment of the present invention with a look-up table. Referring to FIG. 7, the look-up table is divided into a weak over driving modulator A, a non-modulator B, and a strong under driving modulator C. do. In Fig. 7, the vertical axis of the look-up table is the gray level of the data of the N-th frame, and the horizontal axis of the look-up table is the gray level of the data of the N-th frame.

When the data value input to the same pixel of the display panel is larger in the N-th frame F _N than the N-1 th frame F _{N -1} as shown in Equation 4, the input data value is about overdriving modulator. Modulated via (A). The modulation values of the weakly overdriving modulator A of the look-up table are modulation values modulated at an overdriving ratio of 0% to 10%.

In FIG. 7, an overdriving ratio is set to 0% as an example of the present invention. The modulation values of the weakly overdriving modulator A of the look-up table are modulation values obtained by modulating data input to the _N- th frame F _N to obtain a luminance as high as 0% of the target luminance of the data. Here, the luminance as high as 0% of the target luminance means the target luminance itself.

The non-modulator B of the look-up table is a diagonal portion between the weak overdriving modulator A and the strong underdriving modulator C. If the data value to be supplied to the same pixel of the display panel is the same in the frame N-1 _(N F _-1) and the N-th frame (F _N) as shown in Equation 5, the input data value is not modulated is output .

Equal to the data value to be supplied to the pixel smaller in the N-th frame (F _N) than the frame N-1 _(N F _-1) as shown in Equation 6, the input data value of the display panel is steel under driving modulator Modulated via (C). Modulation values of the strong under-driving modulator C of the look-up table are modulation values modulated at an under-driving ratio of 20% to 50%.

In FIG. 7, the underdriving ratio is set to 40% as an example of the present invention. The modulation values of the strong under-driving modulator C of the look-up table are modulated values obtained by modulating a data value input to the _N- th frame F _N to obtain a 40% lower luminance than the target luminance of the data value. it means.

8 is a table showing experimental values comparing the 3D crosstalk ratio of the existing overdrive modulation method and the data modulation method according to an embodiment of the present invention. In FIG. 8, OD Ratio is the overdrive modulation ratio, 3D C / T (%) is the 3D crosstalk ratio (%), Gray is the gray scale change, and the response speed (Rising / Falling) (ms) is the rising of the liquid crystal. Response speed / Falling Response speed.

Referring to FIG. 8, the overdrive modulation ratio (OD Ratio) is set when both the over / under driving ratio is set to 10% (10%) and as shown in FIG. 6, the overdriving ratio is 0% and the underdriving ratio is 40%. Is set to (asymmetrical (0% / 40%)). Gray is divided into the change of G45 and G110, and the change of G110 and G187.

As a result of this experiment, Rising / Falling (ms) was faster when the rising response speed of the liquid crystal was set when both the over / under driving ratio was set to 10% (10%), but the polling response speed of the liquid crystal was overdriving. It was faster when the ratio was set to 0% and the underdriving ratio to 40% (asymmetrical (0% / 40%)). However, the 3D crosstalk ratio (3D C / T (%)) was greatly reduced when the overdriving ratio was set to 0% and the underdriving ratio was set to 40% (asymmetric (0% / 40%)).

Asymmetry (0% / 40%) sets the overdriving ratio to 0% and underdriving ratio to 40%, so the rise response speed of the liquid crystal is lower than when the over / underdriving ratio is set to 10% (10%). Although slow, the polling response speed of the liquid crystal is fast. Although the rising response speed of the liquid crystal is slow, the reason why the 3D crosstalk ratio is remarkably improved is because the peak white luminance is corrected as described above.

9 is a block diagram illustrating a stereoscopic image display device according to an exemplary embodiment of the present invention. FIG. 10 is a detailed block diagram illustrating the data modulator of FIG. 9. In FIG. 9, shutter glasses, their interface circuits, polarized glasses, and the like are omitted.

9, a stereoscopic image display device according to an exemplary embodiment of the present invention may include a display panel DIS, a timing controller 101, a data modulator 110, a data driver circuit 102, and a gate driver circuit 103. And a system board 104, a user input device 120, and the like.

The display panel DIS is a display device for displaying 2D image and 3D image data. When the display panel DIS is implemented as a display panel of a liquid crystal display device, a backlight unit is required. The backlight unit may be implemented as a direct type backlight unit or an edge type backlight unit. Hereinafter, a case where the display panel DIS is implemented as a liquid crystal display device will be described.

In the display panel DIS, a liquid crystal layer is formed between two glass substrates. The display panel DIS includes liquid crystal cells arranged in a matrix by a cross structure of the data lines 105 and the gate lines (or scan lines 106).

The timing controller 101 may switch the operation of the 2D mode and the 3D mode based on the mode signal MODE input from the system board 104 or the mode identification code coded in the input image signal. The timing controller 101 transmits digital data RGB of 2D and 3D images input from the system board 104 to the data modulator 110, and modulates the data RGB ′ by the data modulator 110. Is transmitted to the data driving circuit 102.

The timing controller 101 receives timing signals such as a vertical sync signal Vsync, a horizontal sync signal Hsync, a data enable signal Data Enable (DE), and a dot clock CLK from the system board 104. Control signals for controlling the operation timing of the driving circuit 102 and the gate driving circuit 103 are generated. The control signals include a gate timing control signal for controlling the operation time of the gate driving circuit 103, and a data timing control signal for controlling the operation timing of the data driving circuit 102 and the polarity of the data voltage.

The timing controller 101 or the system board 104 may drive the display panel DIS at a frame frequency of 60 × i (i is an integer of 2 or more) by multiplying an input frame frequency of 60 Hz. The input frame frequency is 50 Hz in the Phase Alternate Line (PAL) scheme and 60 Hz in the National Television Standards Committee (NTSC) scheme. In the PAL method, one frame period is 5 msec when the frame frequency is multiplied by four times to 200 Hz, and one frame period is about 4.16 msec when the frame frequency is multiplied by four times to 240 Hz in the NTSC method.

The gate timing 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 is applied to a gate drive integrated circuit (IC) generating the first gate pulse to control the gate drive IC to generate the first gate pulse. The gate shift clock GSC is a clock signal commonly input to gate drive ICs and is a clock signal for shifting the gate start pulse GSP. The gate output enable signal GOE controls the output of the gate drive ICs.

The data timing control signal includes a source start pulse (SSP), a source sampling clock (SSC), a polarity control signal (POL), and a source output enable signal (SOE). It includes. The source start pulse SSP controls the data sampling start timing of the data driving circuit. The source sampling clock SSC is a clock signal that controls the sampling timing of data in the data driving circuit 102 based on the rising or falling edge. The polarity control signal POL controls the polarity of the data voltage output from the data driving circuit 102. The source output enable signal SOE controls the output timing of the data driver circuit 102. If the digital video data to be input to the data driving circuit 102 is transmitted in mini LVDS (Low Voltage Differential Signaling) interface standard, the source start pulse SSP and the source sampling clock SSC may be omitted.

The data modulator 110 modulates the input left eye or right eye image data RGB _L , RGB _R to reduce crosstalk of the 3D image including the left eye image and the right eye image. Modulate The data modulator 110 includes a frame memory 111 and a look-up table 112. The frame memory 111 is the frame N-1 _(N F _-1) to store data the N-1 frames _(N F _-1) to delay the data for 1 frame period of the N-th frame (F _N), synchronization data and Let's do it. In the 3D mode, if the N-th frame F _{N -1} data is left eye image data, the N-th frame F _N data is right eye image data, and the N-th frame F _{N -1} data is right eye image data. The N th frame F _N data is left eye image data. The look-up table 112 may store modulation values for modulating the input left-eye or right-eye image data RGB _L and RGB _R , for example, modulation values of the look-up table of FIG. 7.

The look-up table 112 receives N-th frame F _N data and N-th frame F _{N -1} data input from the frame memory 111 as an input address, and modulates the modulation values stored in the address. To output the corrected data RGB '. Thus, the look-up table to correct the N-th frame (F _N) of data and the frame N-1 _(N F _-1) data, the N-th frame (F _N) of data to the selected modulation value depending on the result of comparison.

The data modulator 110 may perform data modulation on the 2D image using a conventional overdrive modulation method. In addition, the data modulator 110 may be embedded in the timing controller 101.

Each of the source drive ICs of the data driver circuit 102 includes a shift register, a latch, a digital-to-analog converter, an output buffer, and the like. The data driving circuit 102 latches the digital video data RGB 'under the control of the timing controller 101. The data driving circuit 102 converts the digital video data RGB 'into analog gamma compensation voltages and inverts the polarity of the data voltage in response to the polarity control signal POL.

The gate driving circuit 103 sequentially supplies gate pulses synchronized with the data voltage to the gate lines 106 in response to the gate timing control signals.

The system board 104 timings data and timing signals (Vsync, Hsync, DE, CLK) of 2D or 3D video through an interface such as a low voltage differential signaling (LVDS) interface and a transition minimized differential signaling (TMDS) interface. Supply to the controller 101. The system board 104 supplies a 2D image to the timing controller 101 in the 2D mode, while supplying a 3D image including a left eye image and a right eye image in the 3D mode to the timing controller 101. The system board 104 may transmit data of 2D and 3D images at a frame frequency of 60 × iHz.

The user may select a 2D mode and a 3D mode through the user input device 120. The user input device 120 includes a touch screen attached to or embedded in the display panel DIS, an on screen display (OSD), a keyboard, a mouse, a remote controller, and the like. The system board 104 switches between 2D mode operation and 3D mode operation in response to user data input through the user input device 120. The system board 104 may switch the operation of the 2D mode and the operation of the 3D mode through the 2D / 3D identification code encoded in the data of the input image.

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.

DIS: Display panel SG: Shutter glasses
101: timing controller 102: data driving circuit
103: gate drive circuit 104: system board
105: data line 106: gate line (or scan line)
110: data modulation section 111: frame memory
112: look-up table 120: user input device

Claims (7)

Outputting data by modulating the current frame data within a predetermined overdriving modulation rate when the gray level of the current frame data is greater than the gray level of previous frame data;
Outputting the current frame data as it is when the gray level of the previous frame data and the gray level of the current frame data are the same; And
And modulating and outputting the current frame data within a predetermined underdriving modulation ratio when the gray scale of the current frame data is smaller than the gray scale of the previous frame data.
And the underdriving modulation rate is higher than the overdriving modulation rate. The method of claim 1,
The overdriving modulation ratio is a data modulation ratio corresponding to a luminance as high as 0% to 10% of a target luminance of the current frame data.
And the target luminance is a luminance value corresponding to a gray level of the current frame data. The method of claim 1,
The underdriving modulation ratio is,
The underdriving modulation ratio is a data modulation ratio corresponding to a luminance as low as 20% to 50% of a target luminance of the current frame data.
And the target luminance is a luminance value corresponding to a gray level of the current frame data. If the grayscale of the current frame data is greater than the grayscale of previous frame data, the current frame data is modulated and output within the predetermined overdriving modulation ratio, and if the grayscale of the previous frame data and the grayscale of the current frame data are the same, A data modulator that outputs current frame data as it is and modulates the current frame data within a predetermined underdriving modulation ratio when the gray level of the current frame data is smaller than that of the previous frame data; And
And a controller configured to supply the left and right eye image data modulated by the data modulator to a display panel.
And wherein the underdriving modulation rate is higher than the overdriving modulation rate. The method of claim 4, wherein
The overdriving modulation ratio is a data modulation ratio corresponding to a luminance as high as 0% to 10% of a target luminance of the current frame data.
And the target luminance is a luminance value corresponding to a gray level of the current frame data. The method of claim 1,
The underdriving modulation ratio is,
The underdriving modulation ratio is a data modulation ratio corresponding to a luminance as low as 20% to 50% of a target luminance of the current frame data.
And the target luminance is a luminance value corresponding to a gray level of the current frame data. The data modulator,
A frame memory for storing the previous frame data; And
And a look-up table that receives the previous frame data from the frame memory, receives current frame data from the controller, and outputs a modulation value stored at the address using the previous frame data and the current frame data as input addresses. Stereoscopic display device characterized in that.

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