IPR2015-00863
`Petition for Inter Partes Review of U.S. Patent 7,202,843 - EXHIBIT 1007_Page 1
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`

`

`Patent Application Publication Mar. 13, 2003 Sheet 1 0f 5
`
`US 2003/0048247 A1
`
`FIG.1
`CONVENTIONAL ART
`
`1 FRAME
`
` BRIGHT—
`
`NESS
`
`TIME
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`CONVENTIONAL ART
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`E)
`
`VDE
`II_L_H-
`
`“—1
`
`BRIGHT—
`NESS
`
`Page 2
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`Page 2
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`Patent Application Publication Mar. 13, 2003 Sheet 2 0f 5
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`US 2003/0048247 A1
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`FIG.3
`CONVENTIONAL ART
`
`FM MEI-"ll“
`
`WV
`
`4 MOST SIGNIFICANT BITS
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`annnnnnnn
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`4 MOST SIGNIFICANT BITS
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`4 MOST SIGNIFICANT BITS
`
`F I G . 4
`CONVENTIONAL ART
`
`41
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`Iii;
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`F
`
`n
`
`FRAME
`MEMORY
`
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`42
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`
`
`LOOK-UP
`TABLE
`
`
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`MData
`Out
`
`Page 3
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`Page 3
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`Patent Application Publication Mar. 13, 2003 Sheet 3 0f 5
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`US 2003/0048247 A1
`
`
`
`
`DATADRIVER
`
` LINEMEMORY
`
`MODULATOR
`
`
`54
`
`FIG.5
`
`Page 4
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`Page 4
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`Patent Application Publication Mar. 13, 2003 Sheet 4 0f 5
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`US 2003/0048247 A1
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`FIG.6
`
`In
`
`
`LOOK-UP
`, flggta
`TABLE
`Out
`
` Data
`
`Page 5
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`Page 5
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`Patent Application Publication Mar. 13, 2003 Sheet 5 0f 5
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`US 2003/0048247 A1
`
`FIG.7A
`
`GRAY SCALE LEVEL
`
`NORMAL
`DATA
`(RGB)
`
`
`
`BRIGHT-
`NESS
`
`BRIGHT_
`NESS
`
`GRAY SCALE LEVEL
`
`MODE/LATE
`(AMdata) 0,
`
`
`
`
`
`'HME
`
`GRAYSOALELEVEL
`-
`
`BWGF”_
`NESS
`
`MODULATEI
`DATA
`(AMdma)
`
`-
`
`
`
`
`Qfiifififié
`HFRAMEE
`
`'HME
`
`
`
`VARIATION OF BRIGHTNESS BETWEEN MODULATION
`
`SYSTEMS OF THE PRESENT INVENTION
`AND CONVENTIONAL HIGH-SPEED DRIVING SYSTEM
`
`Page 6
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`Page 6
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`

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`US 2003/0048247 A1
`
`Mar. 13, 2003
`
`METHOD AND APPARATUS FOR DRIVING
`LIQUID CRYSTAL DISPLAY
`
`appears from the moving picture and a display quality is
`deteriorated in the LCD due to a reduction in a contrast ratio.
`
`[0001] This application claims the benefit of Korean
`Application No. P2001-54127 filed on Sep. 4, 2001, which
`is hereby incorporated by reference.
`
`BACKGROUND OF THE INVENTION
`
`FIELD OF THE INVENTION
`
`[0002] The present invention relates to a liquid crystal
`display, and more particularly, to a method and apparatus for
`driving a liquid crystal display. Although the present inven-
`tion is suitable for a wide scope of applications,
`it
`is
`particularly suitable for enhancing a picture quality.
`
`DISCUSSION OF THE RELATED ART
`
`[0003] Generally, a liquid crystal display (LCD) controls
`a light transmittance of each liquid crystal cell in accordance
`with a video signal, thereby displaying a picture. An active
`matrix LCD including a switching device for each liquid
`crystal cell is suitable for displaying a dynamic image. The
`active matrix LCD uses a thin film transistor (TFT) as a
`switching device.
`
`[0004] The LCD has a disadvantage in that it has a slow
`response time due to inherent characteristics of a liquid
`crystal, such as a viscosity and an elasticity, etc. Such
`characteristics can be explained by using the following
`equations (1) and (2):
`r, yd2/Ae|Vf—VF2|
`
`(1)
`
`[0005] where ”Er represents a rising time when a voltage is
`applied to a liquid crystal, Va is an applied voltage, VF
`represents a Freederick transition voltage at which liquid
`crystal molecules begin to perform an inclined motion, d is
`a cell gap of the liquid crystal cells, and y represents a
`rotational viscosity of the liquid crystal molecules.
`
`:Fyd2/d=yd2/K
`
`(2)
`
`[0006] where If represents a falling time at which a liquid
`crystal
`is returned into the initial position by an elastic
`restoring force after a voltage applied to the liquid crystal
`was turned off, and K is an elastic constant.
`
`[0007] A twisted nematic (TN) mode liquid crystal has a
`different response time due to physical characteristics of the
`liquid crystal and a cell gap, etc. Typically, the TN mode
`liquid crystal has a rising time of 20 to 80 ms and a falling
`time of 20 to 30 ms. Since such a liquid crystal has a
`response time longer than one frame interval (i.e., 16.67 ms
`in the case of NTSC system) of a moving picture, a voltage
`charged in the liquid crystal cell is progressed into the next
`frame prior to arriving at a target voltage. Thus, due to a
`motion-blurring phenomenon a screen is blurred out at the
`moving picture.
`
`[0008] Referring to FIG. 1, the conventional LCD cannot
`express desired color and brightness. Upon implementation
`of a moving picture, a display brightness BL fails to arrive
`at a target brightness corresponding to a change of the video
`data VD from one level to another level due to its slow
`
`response time. Accordingly, a motion-blurring phenomenon
`
`In order to overcome such a slow response time of
`[0009]
`the LCD, US. Pat. No. 5,495,265 and PCT International
`Publication No. WO99/05567 have suggested to modulate
`data in accordance with a difference in the data by using a
`look-up table (hereinafter referred to as high-speed driving
`method). This high-speed driving method allows data to be
`modulated by a principle as shown in FIG. 2.
`
`[0010] Referring to FIG. 2, a conventional high-speed
`driving method modulates input data VD and applies the
`modulated data MVD to the liquid crystal cell,
`thereby
`obtaining a desired brightness MBL. This high-speed driv-
`
`ing method increases |V2—VF2| from the above equation (1)
`on the basis of a difference in the data so that a desired
`
`brightness can be obtained in response to a brightness value
`of the input data within one frame interval, thereby rapidly
`reducing a response time of the liquid crystal. Accordingly,
`the LCD employing such a high-speed driving method
`compensates for a slow response time of the liquid crystal by
`A modulating a data value in order to alleviate a motion-
`blurring phenomenon in a moving picture, thereby display-
`ing a picture at desired color and brightness.
`
`the high-speed driving method
`In other words,
`[0011]
`detects a variation in most significant bit data through a
`comparison of most significant bit data MSB of a current
`frame Fn with most significant bit data MSB of the previous
`frame Fn-1. If the variation in the most significant bit data
`MSB is detected, a modulated data corresponding to the
`variation is selected from a look-up table so that the most
`significant bit data MSB is modulated as shown in FIG. 3.
`The high-speed driving method modulates only a part of the
`most significant bits among the input data for reducing a
`memory capacity. For example,
`the high-speed driving
`method can be implemented as shown in FIG. 4.
`
`[0012] Referring to FIG. 4, a conventional high-speed
`driving apparatus includes a frame memory 43 connected to
`a most significant bit output bus line 42 and a look-up table
`44 connected to the most significant bit output bus line 42
`and an output terminal of the frame memory 43.
`
`[0013] The frame memory 43 stores most significant bit
`data MSB during one frame period and supplies the stored
`data to the look-up table 44. Herein, the most significant bit
`data MSB are high-order 4 bits among 8 bits of the source
`data RGB.
`
`[0014] The look-up table 44 makes a mapping of the most
`significant bit data of the current frame Fn inputted from the
`most significant bit output bus line 42 and the most signifi-
`cant bit data of the previous frame Fn-l inputted from the
`frame memory 43 into a modulation data table such as Table
`1 to select modulated most significant bit data Mdata. Such
`modulated most significant bit data Mdata are added to an
`non-modulated least significant bit data LSB from a least
`significant bit output bus line 41 before outputting to a liquid
`crystal display.
`
`Page 7
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`Page 7
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`US 2003/0048247 A1
`
`Mar. 13, 2003
`
`TABLE 1
`
`\DOOQOUIJhbJNI—‘O
`
`ooooooooooooooooo
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`OOOOOOOOOOOOOOHNb—k
`
`Ob—lb—Kb—Kb—lb—Kb—Kb—lb—Kb—Kb—Kb—Kb—KNLNLMN
`
`t—KNNNNNNNNNNWWbbbL’J
`
`Nmmmwmwmwwwgmmmm-P
`
`mmm-b-b-lkbhhhmcxmmcxmm
`
`mggmmmmmmmqqqqqqm
`
`#mmaxcxcxcxquoooooooooomofl
`
`00
`H O
`
`>—H—tOO
`H
`
`MQQQQQQOOQQOCO
`
`11
`14
`14
`14
`14
`13
`13
`13
`13
`12
`12
`12
`11
`10
`10
`
`\O
`12
`12
`12
`11
`11
`11
`10
`10
`
`\D
`
`0‘4-4000000
`
`10
`13
`13
`13
`13
`12
`12
`12
`11
`11
`11
`H
`
`\IOOOOKDDO
`
`
`
`\Dt—‘HNUJUJUJ-h-b-b-b-DUIUIUIUIN
`
`13
`15
`15
`15
`15
`15
`15
`15
`15
`15
`14
`14
`14
`14
`13
`12
`11
`
`14
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`14
`13
`
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`15
`
`In the above Table 1, a left column is for a data
`[0015]
`voltage VDn-1 of the previous frame Fn-1 while an upper-
`most row is for a voltage VDn of the current frame Fn.
`
`[0016] Such a conventional high-speed driving method
`enhances a dynamic contrast ratio in comparison with a
`conventional normal driving method that does not modulate
`the source data. However, the conventional high-speed driv-
`ing method gradually enhances brightness so that a desired
`brightness level is achieved at the end of one frame period.
`Due to this, in the conventional high-speed driving method,
`the dynamic contrast ratio cannot be reached at a desired
`level. Furthermore, a color represented by combining red,
`green, and blue is distorted when those colors are repro-
`duced.
`
`SUMMARY OF THE INVENTION
`
`[0017] Accordingly, the present invention is directed to a
`method and apparatus for driving a liquid crystal display that
`substantially obviates one or more of problems due to
`limitations and disadvantages of the related art.
`
`[0018] Another object of the present invention is to pro-
`vide a method and apparatus for driving a liquid crystal
`display that is adaptive for enhancing a picture quality.
`
`[0019] Additional features and advantages of the inven-
`tion will be set forth in the description which follows and in
`part will be apparent from the description, or may be learned
`by practice of the invention. The objectives and other
`advantages of the invention will be realized and attained by
`the structure particularly pointed out in the written descrip-
`tion and claims hereof as well as the appended drawings.
`
`To achieve these and other advantages and in
`[0020]
`accordance with the purpose of the present invention, as
`embodied and broadly described, a method of driving a
`liquid crystal display includes modulating source data using
`registered data previously provided and supplying the modu-
`lated data to a liquid crystal panel at an initial period of one
`frame period, and applying data different from the modu-
`lated data to the liquid crystal panel at a later period of the
`one frame period.
`
`invention, an
`In another aspect of the present
`[0021]
`apparatus for driving a liquid crystal display includes a
`modulator modulating source data using registered data, and
`a data provider alternatively applying the modulated data
`
`and data different from the modulated data to the liquid
`crystal panel within one frame period.
`
`In a further aspect of the present invention, a liquid
`[0022]
`crystal display includes a liquid crystal display panel dis-
`playing images and having a plurality of data lines and a
`plurality of scanning lines thereon, a modulator modulating
`source data based on registered data previously provided
`therein, and a data provided alternatively applying the
`modulated source data and the source data to the liquid
`crystal panel through the data lines within one frame period.
`
`is to be understood that both the foregoing
`It
`[0023]
`general description and the following detailed description
`are exemplary and explanatory and are intended to provide
`further explanation of the invention as claimed.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0024] The accompanying drawings, which are included
`to provide a further understanding of the invention and are
`incorporated in and constitute a part of this application,
`illustrate embodiments of the invention and together with
`the description serve to explain the principle of the inven-
`tion.
`
`[0025]
`
`In the drawings:
`
`[0026] FIG. 1 is a waveform diagram showing a bright-
`ness variation of a data modulation according to a conven-
`tional liquid crystal display driving method;
`
`[0027] FIG. 2 is a waveform diagram showing a bright-
`ness variation of a data modulation according to a conven-
`tional high-speed driving method;
`
`[0028] FIG. 3 illustrates a modulation of most significant
`bit data in the conventional high-speed driving apparatus
`using 8 bits data;
`
`[0029] FIG. 4 is a block diagram showing a configuration
`of a conventional high-speed driving apparatus for a liquid
`crystal display;
`
`[0030] FIG. 5 is a block diagram showing a configuration
`of a driving apparatus for a liquid crystal display according
`to the present invention;
`
`[0031] FIG. 6 is a block diagram for a data modulator of
`FIG. 5; and
`
`Page 8
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`US 2003/0048247 A1
`
`Mar. 13, 2003
`
`[0032] FIGS. 7A and 7B are graphic diagrams respec-
`tively showing modulated data and brightness of the con-
`ventional high-speed driving and the present invention, and
`FIG. 7C is a graphic diagram illustrating an improvement
`indicated by a dark area.
`
`DETAILED DESCRIPTION OF THE
`ILLUSTRATED EMBODIMENTS
`
`[0033] Reference will now be made in detail to the illus-
`trated embodiments of the present invention, examples of
`which are illustrated in the accompanying drawings. Wher-
`ever possible,
`the same reference numbers will be used
`throughout the drawings to refer to the same or like parts.
`
`[0034] FIG. 5 is a schematic diagram for a driving appa-
`ratus for a liquid crystal display (LCD) according to the
`present invention.
`
`[0035] The LCD driving apparatus includes a liquid crys-
`tal display panel 57 having a plurality of data lines 55 and
`a plurality of gate lines 56 crossing each other and having
`TFT’s provided at each intersection to drive liquid crystal
`cells Clc. A data driver 53 supplies data to the data lines 55
`of the liquid crystal display panel 57. A gate driver 54
`applies a scanning pulse to the gate lines 56 of the liquid
`crystal display panel 57. A timing controller 51 receives
`digital video data and synchronizes signals H and V. A data
`modulator 52 is connected between the timing controller 51
`and the data driver 53 to modulate input data RGB. The LCD
`driving apparatus further includes a switch 58 selecting any
`one of a modulated data AMdata and the normal input RGB.
`A line memory 59 is connected between the timing control-
`ler 51 and the switch 58. Herein, the normal data is non-
`modulated data.
`
`[0036] The liquid crystal display panel 57 has a liquid
`crystal formed between two glass substrates and has the data
`lines 55 and the gate lines 56 provided on the lower glass
`substrate in such a manner to perpendicularly cross each
`other. The TFT provided at each intersection between the
`data lines 55 and the gate lines 56 responds to a scanning
`pulse to apply data on the data lines 55 to the liquid crystal
`cell Clc. To this end, a gate electrode of the TFT is connected
`to the gate lines 56 while a source electrode is connected to
`the data lines 55. The drain electrode of the TFT is connected
`
`to each pixel electrode of the liquid crystal cell Clc.
`
`[0037] The timing controller 51 rearranges digital video
`data supplied from a digital video card (not shown). The
`RGB data rearranged by the timing controller 51 are sup-
`plied to the data modulator 52 and the line memory 59.
`Further,
`the timing controller 51 creates timing control
`signals, such as a dot clock Dclk, a gate start pulse GSP, a
`gate shift clock GSC (not shown), an output enable/disable
`signal, and a polarity control signal using horizontal and
`vertical synchronizing signals H and V to control the data
`driver 53 and the gate driver 54. The dot clock Dclk and the
`polarity control signal are applied to the data driver 53 while
`the gate start pulse GSP and the gate shift clock GSC are
`applied to the gate driver 54. Herein, frequencies of the
`timing control signals and the polarity control signal gen-
`erated in the timing controller 51 have a polarity opposing
`to those of the conventional timing control signals and the
`prior polarity control signal. Also, magnitudes of the timing
`control signals and the polarity control signal are twice
`greater than those of the conventional timing control signals
`
`and the prior polarity signal. The timing controller 51 also
`provides a switching control signal SW allowing the switch
`58 to be switched twice within one frame interval. To this
`
`end, the switching control signal SW is inverted in a logic
`value within one frame interval. In other words, the logic
`value of the switching control signal SW is inverted at each
`1/2 period in comparison with the conventional vertical
`synchronous signal V. The timing controller 51 controls the
`switch 58 using the switching control signal SW.
`
`[0038] The gate driver 54 includes a shift register sequen-
`tially generating a scanning pulse (i.e., a gate high pulse) in
`response to the gate start pulse GSP and the gate shift clock
`GSC applied from the timing controller 51. A level shifter
`shifts a voltage of the scanning pulse into a level suitable for
`driving the liquid crystal cell Clc. The TFT is turned on in
`response to the scanning pulse to apply Video data on the
`data lines 55 to the pixel electrode of the liquid crystal cell
`Clc. Each gate start pulse GSP and each gate shift clock GSC
`have a frequency twice greater than those of the conven-
`tional gate start pulse and the gate shift clock. Thus, they
`allow all scanning lines 56 on the liquid crystal display panel
`57 to be scanned twice within one frame interval.
`
`[0039] The data driver 53 is sequentially supplied with the
`modulated data AMdata and the normal data RGB from the
`switch 58 within one frame interval. It also receives the dot
`
`clock Dclk from the timing controller 51. The data driver 53
`continuously samples each of the modulated data AMdata
`and the normal data RGB in synchronization with the dot
`clock Dclk. Thereafter,
`the data driver 53 latches the
`sampled data for one line. The data for one line latched by
`the data driver 53 is converted into analog data and applied
`to the data lines 55 in each scanning period. Further, the data
`driver 53 may apply a gamma voltage corresponding to the
`modulated data to the data line 55. The dot clock Dclk has
`
`a frequency twice greater than that of the conventional dot
`clock. Thus, each modulated data AMdata and the normal
`data RGB are applied to each liquid crystal cell Clc within
`one frame interval.
`
`[0040] The data modulator 52 can modulate 4 most sig-
`nificant bits of the normal data RGB through a comparison
`of the data, as shown in FIG. 4. Alternatively,
`the data
`modulator 52 also can modulate the entire bits of the normal
`
`data RGB by comparing the entire bits of the normal data
`RGB, as shown in FIG. 6. To this end, the data modulator
`52 includes a frame memory 61 storing 8 bits of the normal
`data RGB received from the timing controller 51 and a
`look-up table 62 comparing the 8 bits of the normal data
`from the timing controller 51 with the 8 bits of the normal
`data from the frame memory 61 to modulate the 8 bits of the
`normal data RGB into 8 bits of modulated data AMdata.
`
`Each modulated data AMdata stored into the look-up table
`61 is obtained from following equation (3) to (5):
`
`VDn<VDn—1—>MDNn< VDn
`
`VDn=VDn—1—>MDNn= VDn
`
`VDn>VDn—1—>MDNn> VDn
`
`(3)
`
`(4)
`
`(5)
`
`[0041] where VDn-1 represents a data voltage in the
`previous frame, VDn is a data voltage of the current frame,
`and MVDn represents a modulated data voltage.
`
`[0042] The switch 58 responds to the switching control
`signal SW from the timing controller 51 and sequentially
`
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`US 2003/0048247 A1
`
`Mar. 13, 2003
`
`applies the modulated data AMdata and the normal data
`RGB to the data driver 53 within one frame.
`
`[0043] The line memory 59 delays the normal data RGB
`during the period of one line. The period of one line is a time
`for which the modulated data AMdata is applied to the data
`driver 53.
`
`[0044] FIGS. 7A and 7B illustrate variations in brightness
`in response to the applied voltage to the liquid crystal panel
`57 according to the conventional art and the present inven-
`tion, respectively. FIG. 7C illustrates an improvement in the
`variations in brightness by the present invention indicated by
`a dark area. One frame interval in the present invention is
`divided into an odd-numbered sub-field OSF and an even-
`
`numbered sub-field ESF. The period of each odd-numbered
`sub-field OSF and each even-numbered sub-field ESF can be
`
`appropriately adjusted within one frame interval.
`
`In FIG. 7A, “VD” is a normal data voltage and
`[0045]
`“BL” is brightness varying with the normal data voltage VD.
`“MVD” is a modulated data voltage modulated by the
`conventional high-speed driving system and “MBL” is
`brightness varying with the modulated data voltage MVD.
`“AMVD” is a modulated data voltage modulated by the
`liquid crystal display driving apparatus and method accord-
`ing to the present invention and “AMBL” is brightness
`varying with the modulated data voltage AMVD.
`
`In the odd-numbered sub-field OSF, the modulated
`[0046]
`data AMdata modulated by the data modulator 52 is applied
`to the liquid crystal panel 57. Continuously, the normal data
`RGB, which is not modulated, is supplied to the liquid
`crystal panel 57 during the even-numbered sub-field ESF.
`
`[0047] Since the modulated data voltage in the first odd-
`numbered sub-field OSF is higher (or lower) than the normal
`data voltage in the even-numbered sub-field ESF, an effec-
`tive voltage of the modulated data voltage applied to the
`liquid crystal cell Clc is higher (or lower) than that of the
`normal data voltage. Accordingly, brightness of the liquid
`crystal cell reaches at a desired brightness level within the
`period of the odd-numbered sub-field OSF shorter than one
`frame. In other words, the modulated data voltage applied in
`the odd-numbered sub-field OSF can be higher or lower than
`the inputted current normal data voltage depend upon con-
`ditions satisfying the above equations (3) to (5).
`
`[0048] On the other hand, the normal data voltage applied
`in the even-numbered sub-field ESF forces to maintain the
`
`desired brightness level achieved at the odd-numbered sub-
`field OSF during the period of the even-numbered sub-field
`ESF.
`
`[0049] As shown in FIG. 7C, the liquid crystal display
`drive apparatus and method according to the present inven-
`tion allow the brightness of the liquid crystal panel 57 to
`arrive rapidly at the desired brightness level and to maintain
`the desired level during the constant period. Meanwhile, the
`conventional high-speed driving system forces to each the
`desired brightness level only at the end of the frame because
`the brightness is gradually varied with the modulated data
`maintaining a constant voltage within one frame.
`
`[0050] On the other hand, the modulated data AMdata of
`the high-speed driving apparatus according to present inven-
`tion can be adjusted to be higher than that of the conven-
`tional high-speed driving system. Due to this fact, if the
`
`modulated data AMdata of the present invention is applied
`to the liquid crystal panel 57 through the entire period of the
`frame in such a manner to identify with the conventional
`high-speed driving system, a white pattern (non-desired)
`may be generated by an over-shoot. In such a case, a picture
`quality may be deteriorated.
`
`[0051] As described above, the LCD drive apparatus and
`method according to the present invention apply the normal
`data to the liquid crystal panel at the initial half period of the
`frame after supplying of the modulated data to the liquid
`crystal panel during the later half period of the frame. Thus,
`a desired brightness level
`is achieved within the initial
`period of the frame. Accordingly, the LCD drive apparatus
`and method in the present invention enhances a dynamic
`contrast and a color reproducibility. As a result, the LCD
`drive apparatus and method of the present invention provide
`with a high display quality.
`
`[0052] The data modulator 52 may be implemented by
`other means, such as a programmable software and a micro-
`processor for carrying out the present invention, rather than
`a look-up table. The present invention can also be applied to
`a digital flat display device, which requires a data modula-
`tion, such as a plasma display panel, an electro-lumines-
`cence display device, and an electric field emitting device
`and so on. Furthermore, the switch and the line memory can
`be combined in one unit together with the timing controller
`or the data driver.
`
`It will be apparent to those skilled in the art that
`[0053]
`various modifications and variations can be made in the
`
`method and apparatus for driving the liquid crystal display
`of the present invention without departing from the spirit or
`scope of the inventions. Thus, it is intended that the present
`invention covers the modifications and variations of this
`
`invention provided they come within the scope of the
`appended claims and their equivalents.
`
`What is claimed is:
`
`1. A method of driving a liquid crystal display, compris-
`ing:
`
`modulating source data using registered data previously
`provided and supplying the modulated data to a liquid
`crystal panel at an initial period of one frame period;
`and
`
`applying data different from the modulated data to the
`liquid crystal panel at a later period of the one frame
`period.
`2. The method according to claim 1, wherein the data
`applied to the liquid crystal panel at the later period is the
`source data.
`
`3. The method according to claim 1, further comprising:
`
`dividing the source data of a current frame period into
`most significant bit data and least significant bit data;
`
`delaying the most significant bit data for one frame
`period; and
`
`selecting the modulated data through a comparison of the
`current and delayed most significant bit data.
`4. The method according to claim 1, further comprising:
`
`delaying entire bit data of the source data for one frame
`period; and
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`US 2003/0048247 A1
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`Mar. 13, 2003
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`selecting the modulated data through a comparison of the
`current and delayed entire bits of the source data.
`5. The method according to claim 1, wherein the later
`period begins at a half period of the one frame period.
`6. The method according to claim 2, wherein the source
`data are not applied to the liquid crystal panel while the
`modulated data are applied thereto.
`7. An apparatus for driving a liquid crystal display,
`comprising:
`
`a modulator modulating source data using registered data;
`and
`
`a data provider alternatively applying the modulated data
`and data different from the modulated data to the liquid
`crystal panel within one frame period.
`8. The apparatus according to claim 7, wherein the data
`different from the modulated data is the source data.
`
`9. The apparatus according to claim 7, wherein the
`modulator comprises,
`
`a delay circuit delaying most significant bit data of the
`source data of a current frame and outputting one frame
`delayed most significant bit data; and
`
`a look-up table selecting the registered data through a
`comparison of the current and delayed most significant
`bit data.
`
`10. The apparatus according to claim 7, wherein the
`modulator selects the registered data through a comparison
`of entire bits of the current and delayed source data.
`11. The apparatus according to claim 7, wherein the data
`provider comprises,
`
`a switch alternatively switching the data and the modu-
`lated data;
`
`a timing controller applying the source data to the modu-
`lator and controlling a switching time of the switch; and
`
`a line memory holding the data for less than one frame
`period and outputting the data to the switch.
`12. The apparatus according to claim 11, wherein the
`timing controller generates
`a switching control signal
`inverted in a logic value within the one frame period to
`alternatively switch the modulated data and the source data
`within the one frame period.
`13. The apparatus according to claim 11, wherein the
`timing controller generates a dot clock a frequency twice
`greater than that of the source data to sequentially select the
`modulated data and the source data within the one frame
`
`period.
`
`14. The apparatus according to claim 11, wherein the
`switch alternatively switches the source data and the modu-
`lated data at a half period of the one frame period.
`15. The apparatus according to claim 7, wherein the data
`provider includes a delay circuit delaying the source data
`while the modulated data are applied to the liquid crystal
`panel.
`16. The apparatus according to claim 7, further compris-
`ing,
`
`a data driver applying the modulated data and the source
`data received alternatively from the switch to a plural-
`ity of data lines on the liquid crystal panel; and
`
`a scanning driver applying a scanning pulse to a plurality
`of scanning lines on the liquid crystal panel.
`17. The apparatus according to claim 16, wherein the
`scanning pulse has a frequency high enough to scan twice
`entire scanning lines on the liquid crystal panel within the
`one frame period.
`18. A liquid crystal display comprising:
`
`a liquid crystal display panel displaying images and
`having a plurality of data lines and a plurality of
`scanning lines thereon;
`
`a modulator modulating source data based on registered
`data previously provided therein; and
`
`a data provided alternatively applying the modulated
`source data and the source data to the liquid crystal
`panel through the data lines within one frame period.
`19. The liquid crystal display according to claim 11,
`wherein the data provider comprises,
`
`a switch alternatively switching the data and the modu-
`lated data;
`
`a timing controller applying the source data to the modu-
`lator and controlling a switching time of the switch; and
`
`a line memory holding the data for less than one frame
`period and outputting the data to the switch.
`20. The liquid crystal display panel according to claim 18,
`wherein the data provider applies the modulated source data
`to the liquid crystal display for a first half frame period and
`the source data to the liquid crystal display for a second half
`period.
`
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