A kind of driving method of liquid crystal display and drive unit
Technical field
The present invention relates to lcd technology, relate in particular to a kind of driving method and drive unit of liquid crystal display.
Background technology
Power consumption is the principal element that can electronic equipment be widely used, and the power consumption of display device is the important component part of electronic apparatus system overall power.At present, liquid crystal display (LCD, Liquid Crystal Display) is widely used in electronic equipment, and along with application further expands, the market share is also increasing gradually.Wherein Thin Film Transistor-LCD (TFT-LCD, Thin Film Transistor Liquid Crystal Display) is the main product in liquid crystal display.Liquid crystal panel is the vitals in liquid crystal display, mainly comprises array base palte and color membrane substrates that box is arranged, is filled with liquid crystal layer therebetween.
Fig. 1 is the electrical block diagram of existing array base palte, as shown in Figure 1, is formed with many grid lines 101 and the data line 102 that intersect in length and breadth on array base palte, encloses and forms multiple pixel cells 103 that matrix form is arranged.In each pixel cell 103, be equipped with thin film transistor (TFT) (TFT, Thin Film Transistor) 104.For the TFT104 in each pixel cell 103, its function is equivalent to a switching tube.The patterns such as grid line 101, data line 102 and pixel cell 103 are referred to as conductive pattern in the prior art, and the grid electrode insulating layer and the passivation layer that in the pattern processes such as formation grid line 101, data line 102 and pixel cell 103, form are referred to as insulation course.Conductive pattern and insulation course can adopt existing technique to form.In the time will charging to certain a line pixel cell 103, can, by grid line 101 corresponding to this row by the TFT104 conducting of these row pixel cell 103 correspondences, then apply target voltage by data line 102 to this row pixel cell 103.After the pixel electrode of pixel cell 103 is fully charged, even if TFT104 disconnects, because the demonstration voltage being added on liquid crystal layer can be stored in the memory capacitance of each pixel cell 103, therefore liquid crystal layer can stably be worked.
Along with the continuous increase of liquid crystal panel size, the load of liquid crystal panel is corresponding increase also, causes power consumption significantly to rise, and therefore, the power consumption that how to reduce liquid crystal panel becomes problem demanding prompt solution.The dynamic power consumption of existing liquid crystal panel only can be reduced to 50% of original power consumption.
Summary of the invention
In view of this, fundamental purpose of the present invention is to provide a kind of driving method and drive unit of liquid crystal display, can be by the dynamic power reduction of liquid crystal panel to 25% of original power consumption.
For achieving the above object, technical scheme of the present invention is achieved in that
The invention provides a kind of method for driving liquid crystal display, described method comprises:
In current scan line, between the pixel cell of adjacent columns, carry out electric charge and share, the voltage in the pixel cell storage capacitors of each adjacent columns in current scan line is averaged;
Between the pixel cell of same column, carry out secondary charges in current scan line and in next scan line and share, by the voltage in each pixel cell storage capacitors in current scan line, with next scan line in voltage in each pixel cell storage capacitors average;
Each pixel cell in current scan line is charged.
In such scheme, in described current scan line, between the pixel cell of adjacent columns, carry out electric charge and share, the voltage in the pixel cell storage capacitors of each adjacent columns in current scan line is averaged, comprising:
In the current scan line of horizontal drive circuit control, the TFT of each pixel cell is in closed condition;
Column drive circuit connects two data lines adjacent on liquid crystal panel, the pixel cell conducting in current scan line in adjacent columns;
Charging neutrality between opposite polarity adjacent pixel unit on current scan line, the average voltage in current scan line in each adjacent columns pixel cell storage capacitors.
In such scheme, between the pixel cell of same column, carrying out secondary charges in described current scan line and in next scan line shares, voltage in each pixel cell storage capacitors in voltage in each pixel cell storage capacitors in current scan line and next scan line is averaged, comprising:
In the current scan line of horizontal drive circuit control, in the TFT of each pixel cell and next scan line, the TFT of each pixel cell opens;
Column drive circuit disconnects two data lines adjacent on liquid crystal panel, and the pixel cell in current scan line in adjacent columns disconnects;
Charging neutrality between the same column pixel cell of current scan line and next scan line, by current scan line with next scan line in voltage in same column pixel cell storage capacitors average again.
In such scheme, described each pixel cell in current scan line is charged, comprising:
In the current scan line of horizontal drive circuit control, the TFT of each pixel cell opens, and the TFT that controls each pixel cell in next scan line closes;
Column drive circuit output memory capacitance driving voltage, to each pixel cell of current scan line, is each pixel cell charging.
In such scheme, described horizontal drive circuit output line scan signals is to the each grid line on liquid crystal panel, when line scan signals on described grid line is high level, the TFT that in this grid line institute corresponding row, each pixel cell is corresponding opens, in the time that described line scan signals is low level, in this grid line institute corresponding row, TFT corresponding to each pixel cell closes.
In such scheme, described column drive circuit connects the each data line on described liquid crystal panel by switches set, a corresponding described data line of described switches set;
In the time of adjacent two corresponding two the switches set conductings of data line of described column drive circuit control, described adjacent two data lines connect, in the time that corresponding two switches set of adjacent two data lines of described column drive circuit control disconnect, described adjacent two data lines disconnect.
In such scheme, described method also comprises: to each pixel cell of next scan line carry out described electric charge share, secondary charges share after charging, and so forth, until last column pixel cell of liquid crystal panel has charged in liquid crystal display.
The present invention also provides a kind of driving device of liquid crystal display, and described device comprises: horizontal drive circuit and column drive circuit, wherein,
Horizontal drive circuit and column drive circuit, share for carrying out electric charge between the pixel cell of the current scan line adjacent columns of co-controlling, and the voltage in the pixel cell storage capacitors of each adjacent columns in current scan line is averaged; And, and between the pixel cell of same column, carry out secondary charges in the current scan line of described column drive circuit co-controlling and in next scan line and share, the voltage in each pixel cell storage capacitors in the voltage in each pixel cell storage capacitors in current scan line and next scan line is averaged;
Described column drive circuit, also, for after the voltage in each pixel cell storage capacitors in the voltage in each current scan line pixel cell storage capacitors and next scan line is averaged, charges to each pixel cell in current scan line.
In such scheme, described horizontal drive circuit, open or close for the TFT that controls the each pixel cell of current scan line, and in the time that the TFT that controls each pixel cell in current scan line opens, the TFT that controls each pixel cell in next scan line opens or closes;
Described column drive circuit, for two data lines adjacent on liquid crystal panel are connected or disconnected, controls pixel cell conducting or disconnection in adjacent columns in current scan line.
In such scheme, described horizontal drive circuit, also for exporting line scan signals to the each grid line on liquid crystal panel, when line scan signals on described grid line is high level, the TFT that in this grid line institute corresponding row, each pixel cell is corresponding opens, in the time that described line scan signals is low level, in this grid line institute corresponding row, TFT corresponding to each pixel cell closes.
In such scheme, described column drive circuit comprises switches set, and described switches set is used for connecting the data line of the each adjacent columns on described liquid crystal panel, a corresponding described data line of described switches set;
In the time of adjacent two corresponding two the switches set conductings of data line of described column drive circuit control, described adjacent two data lines connect, in the time that corresponding two switches set of adjacent two data lines of described column drive circuit control disconnect, described adjacent two data lines disconnect.
Method for driving liquid crystal display provided by the invention and device, by each pixel cell of current scan line is carried out, electric charge is shared and secondary charges is shared, make the voltage of each pixel cell be adjusted into 1/4th of primary voltage, afterwards, again each pixel cell of current scan line is charged, so, while making to charge the dynamic loss of liquid crystal panel with respect to original power-dissipation-reduced 75%.
Brief description of the drawings
Fig. 1 is the electrical block diagram of existing array base palte;
Fig. 2 is the realization flow figure of liquid crystal display driving method of the present invention;
Fig. 3 is the composition structural representation of LCD driving mechanism in the embodiment of the present invention one;
Fig. 4 is the sequential chart of line scan signals that horizontal drive circuit produces in the embodiment of the present invention one;
Fig. 5 produces the sequential chart of row control signal for column drive circuit in the embodiment of the present invention one;
Fig. 6 is the annexation schematic diagram of horizontal drive circuit, column drive circuit and liquid crystal panel in the embodiment of the present invention one;
Fig. 7 be in the embodiment of the present invention one upper once drive finish after the polarity schematic diagram of each pixel cell on liquid crystal panel;
Fig. 8 is R on liquid crystal panel in the embodiment of the present invention one
non row, between each pixel cell, carry out the polarity schematic diagram after electric charge is shared;
Fig. 9 is R on liquid crystal panel in the embodiment of the present invention one
neach pixel cell and R on row
n+1on row, between each pixel cell, carry out the polarity schematic diagram after secondary charges is shared;
Figure 10 is in the embodiment of the present invention one, to be R on liquid crystal panel
npolarity schematic diagram when each pixel cell charges on row;
Wherein, 101, grid line, 102, data line, 103, pixel cell, 104, TFT, 301, DC-DC circuit, 302, sequential control circuit, 303, Gamma circuit, 304, horizontal drive circuit, 305, column drive circuit, 306, backlight drive circuit module, 307, backlight, 308, liquid crystal panel.
Embodiment
In LCD driving circuit, the general power consumption of digital control circuit part is less, and its power consumption accounts for way circuit power consumption less than 10%.And the power consumption of row drive part roughly can be divided into: quiescent dissipation and dynamic power consumption two parts.Wherein, quiescent dissipation depends primarily on operational amplifier and the DC bias circuit thereof of driving circuit, dynamic power consumption mainly by LCD pixel discharge and recharge loss determine, total dynamic power consumption can obtain based on formula (1).
Pdynamic=V
dd*N*C
1*V
swing*Frow/2 (1)
In formula (1), V
ddrepresent supply voltage, N indicate drive columns, C
1represent that every row drive the size of electric capacity, V
swingrepresent the average amplitude of fluctuation of output voltage, i.e. difference between original voltage of pixel cell and the voltage that need reach on liquid crystal panel, Frow represents line-scanning frequency.Wherein, N, C
1determine by the performance parameter of the LCD that will drive with Frow, conventionally definite constant, only have V
swingrelevant with driving circuit itself.Therefore, basic thought of the present invention is: a kind of method for driving liquid crystal display and device are provided, can reduce V
swingthereby, reach the object that reduces power consumption.
Method for driving liquid crystal display of the present invention, as shown in Figure 2, mainly can comprise the steps:
Step 201: carry out electric charge in current scan line between the pixel cell of adjacent columns and share, the voltage in the pixel cell storage capacitors of each adjacent columns in current scan line is averaged;
Particularly, in the current scan line of horizontal drive circuit control, the TFT of each pixel cell is in closed condition, on the column drive circuit control liquid crystal panel that comprises switches set, two adjacent data lines connect and disconnect, in the time that corresponding switches set is closed, pixel cell conducting in current scan line in adjacent columns, opposite polarity pixel cell charging neutrality between any two on current scan line, the average voltage in current scan line in each row pixel cell storage capacitors.
Step 202: between the pixel cell of same column, carry out secondary charges in current scan line and in next scan line and share, by current scan line with next scan line in voltage in same column pixel cell storage capacitors average again;
Particularly, in the current scan line of horizontal drive circuit control, in the TFT of each pixel cell and next scan line, the TFT of each pixel cell opens, in column drive circuit, corresponding switches set disconnects, two data lines adjacent on liquid crystal panel disconnect, pixel cell in current scan line in adjacent columns disconnects, between the same column pixel cell of current scan line and next scan line, secondary charges is shared, by current scan line with next scan line in voltage in same column pixel cell storage capacitors average again.
Step 203: each pixel cell in current scan line is charged.
Particularly, in the current scan line of horizontal drive circuit control, the TFT of each pixel cell opens, and the TFT that controls each pixel cell in next scan line closes; Column drive circuit output memory capacitance driving voltage, to each pixel cell of current scan line, is each pixel cell charging.
Here, described method also comprises: to each pixel cell of next scan line carry out described electric charge share, secondary charges share after charging, and so forth, until last column pixel cell of liquid crystal panel has charged in liquid crystal display.
Wherein, described horizontal drive circuit output line scan signals is to the each grid line on liquid crystal panel, when line scan signals on described grid line is high level, the TFT that in this grid line institute corresponding row, each pixel cell is corresponding opens, in the time that described line scan signals is low level, in this grid line institute corresponding row, TFT corresponding to each pixel cell closes.
Wherein, described column drive circuit connects the each data line on described liquid crystal panel by switches set, a corresponding described data line of described switches set; In the time of adjacent two corresponding two the switches set conductings of data line of described column drive circuit control, described adjacent two data lines connect, in the time that corresponding two switches set of adjacent two data lines of described column drive circuit control disconnect, described adjacent two data lines disconnect.
Accordingly, the present invention also provides a kind of driving device of liquid crystal display, it is characterized in that, described device comprises: horizontal drive circuit and column drive circuit, wherein, horizontal drive circuit and column drive circuit, share for carrying out electric charge between the pixel cell of the current scan line adjacent columns of co-controlling, and the voltage in the pixel cell storage capacitors of each adjacent columns in current scan line is averaged; And, and between the pixel cell of same column, carry out secondary charges in the current scan line of described column drive circuit co-controlling and in next scan line and share, the voltage in each pixel cell storage capacitors in the voltage in each pixel cell storage capacitors in current scan line and next scan line is averaged; Described column drive circuit, also, for after the voltage in each pixel cell storage capacitors in the voltage in each current scan line pixel cell storage capacitors and next scan line is averaged, charges to each pixel cell in current scan line.
Particularly, described horizontal drive circuit, opens or closes for the TFT that controls the each pixel cell of current scan line, and in the time that the TFT that controls the each pixel cell of current scan line opens, the TFT that controls each pixel cell in next scan line opens or closes; Described column drive circuit, for two data lines adjacent on liquid crystal panel are connected or disconnected, controls pixel cell conducting or disconnection in adjacent columns in current scan line.
Here, described horizontal drive circuit, can be for output line scan signals to the each grid line on liquid crystal panel, when line scan signals on described grid line is high level, the TFT that in this grid line institute corresponding row, each pixel cell is corresponding opens, in the time that described line scan signals is low level, in this grid line institute corresponding row, TFT corresponding to each pixel cell closes.
Here, described column drive circuit comprises switches set, and described switches set is used for connecting the each data line on described liquid crystal panel, a corresponding described data line of described switches set; In the time of adjacent two corresponding two the switches set conductings of data line of described column drive circuit control, described adjacent two data lines connect, in the time that corresponding two switches set of adjacent two data lines of described column drive circuit control disconnect, described adjacent two data lines disconnect.
Embodiment mono-
In the present embodiment, as shown in Figure 3, driving device of liquid crystal display mainly comprises DC-DC circuit (DCDC) 301, sequential control circuit (T to the composition structure of driving device of liquid crystal display
cON) 302, Gamma circuit (Gamma Circuit) 303, horizontal drive circuit 304, column drive circuit 305 and backlight drive circuit module (B/L Circuit) 306.
Wherein, DC-DC circuit 301 is for providing analog voltage (AVDD), digital voltage (DVDD), gate off voltage (V
off), grid cut-in voltage (V
on); Sequential control circuit 302 is the signal from system end in order to conversion, the data input of coupling column drive circuit, produce various timing control signals simultaneously, comprise frame start signal (STV signal), row clock sweep signal (CPV signal), data load signal (Load signal), polarity inversion signal (POL signal); The analog voltage (AVDD) of input is converted to gray scale reference voltages by Gamma circuit 303, offers column drive circuit 305.The backlight (Backlight) 307 of backlight drive circuit module 306 connecting fluid crystal displays, for the backlight 307 of liquid crystal display provides driving voltage (V
out).
The grid line of liquid crystal panel (Panel) 308 on horizontal drive circuit 304 connecting fluid crystal displays, the STV signal producing according to sequential control circuit 302 and CPV signal, generate line scan signals and also output on the gate line of liquid crystal panel 308, successively the TFT of every a line pixel cell on liquid crystal panel 308 described in conducting.Here the line scan signals that, horizontal drive circuit 304 generates as shown in Figure 4.
The data line of liquid crystal panel 308 on column drive circuit 305 connecting fluid crystal displays, column drive circuit 305 receives Load signal and the POL signal that sequential control circuit 302 sends, generate row control signal, and the gray scale reference voltages of exporting according to Gamma circuit 303 produces corresponding memory capacitance driving voltage, the memory capacitance C to pixel cell based on described memory capacitance driving voltage and row control signal
stcharge.Here the row control signal that, column drive circuit 305 generates as shown in Figure 5.
As shown in Figure 6, driving circuit is by the data line of liquid crystal panel (Panel) on the switches set connecting fluid crystal display of self, and by conducting and the disconnection of the each switches set of described row control signal control, described switches set is for controlling connection and the disconnection between adjacent two data lines, particularly, a corresponding data line of switches set, in the time of two adjacent switches set conductings, described two adjacent switch groups respectively two adjacent data lines of correspondence connect, in the time that described two adjacent switches set disconnect, corresponding two adjacent data lines disconnect.
Particularly, as shown in Figure 6, a switches set comprises three switches, is respectively switch S, switch S
1and switch S
2, switch S gauge tap S
1and switch S
2.On described liquid crystal panel, comprise N bar data line (N is greater than 0 even number), be respectively data line 1, data line 2, data line 3, data line 4, ..., data line N-1, data line N, corresponding, column drive circuit comprises respectively switches set 1, switches set 2, switches set 3, switches set 4, ..., switches set N-1, switches set N, wherein, switches set 1, switches set 2, switches set 3, switches set 4, ..., switches set N-1, switches set N is connection data line 1 respectively, data line 2, data line 3, data line 4, ..., data line N-1, data line N.The switch S of switches set 1
1connection data line 1, the switch S of switches set 1
2connection data line 2, the switch S of switches set 2
1connection data line 1, the switch S of switches set 2
2connection data line 2.The switch S of switches set 3
1connection data line 3, the switch S of switches set 3
2connection data line 4, the switch S of switches set 4
1connection data line 3, the switch S of switches set 4
2connection data line 4.So analogize the switch S of switches set N-1
1connection data line N-1, the switch S of switches set N-1
2connection data line N, the switch S of switches set N
1connection data line N-1, the switch S of switches set N
2connection data line N.
Wherein, switch S, S
1, S
2by column drive circuit control, each switch is to be made up of metal-oxide half field effect transistor (MOSFET, Metal-Oxide-Semiconductor Field-Effect Transistor).Particularly, the switch S of each switches set is controlled by the switch S control signal of being exported row control signal at described arrange control circuit, and in the time that switch S control signal is high level, the switch S of each switches set is all closed, in the time that switch S control signal is low level, the switch S of each switches set all disconnects; The switch S of each switches set
1by the switch S of being exported row control signal at described arrange control circuit
1control signal is controlled, in switch S
1when control signal is high level, the switch S of each switches set
1all closed, in switch S
1when control signal is low level, the switch S of each switches set
1all disconnect; The switch S of each switches set
2by the switch S of being exported row control signal at described arrange control circuit
2control signal is controlled, in switch S
1when control signal is high level, the switch S of each switches set
2all closed, in switch S
2when control signal is low level, the switch S of each switches set
2all disconnect.
In the present embodiment, suppose that LCD carries out monochrome and drives, the positive voltage of driving is V
h, negative voltage is V
l.Once drive polarity after finishing as shown in Figure 7 upper, now, in liquid crystal display driving process to any a line R
nthe process that in row, pixel cell charges, specifically can comprise the steps:
Step 1, the line scan signals of horizontal drive circuit output is in as the state as shown in 1. in Fig. 4, R
nthe line scan signals of row is low level, R
nin row, the TFT of each pixel cell is in closed condition, and now, the row control signal of column drive circuit is that now, the control signal of switch S is low level, switch S as the state as shown in 1. in Fig. 5
1and switch S
2control signal be high level, switch S is off-state, S
1and S
2closure state, in Fig. 6, data line 1 is connected with data line 2, and data line 3 is connected with data line 4 ..., data line N-1 is connected with data line N, R
nthe first row pixel cell of row and the pixel cell conducting of secondary series, the pixel cell conducting of tertial pixel cell and the 4th row ..., N-1 row pixel cell and the conducting of N row pixel cell, R
nin row, between each pixel cell, carry out electric charge and share, make R
nin row, the charges of different polarity of memory capacitance neutralization in each pixel cell, so, as shown in Figure 8, obtains R
nmagnitude of voltage in row in each pixel cell storage capacitors is (V
h+ V
l)/2;
Step 2: the line scan signals of horizontal drive circuit output is in as the state as shown in 2. in Fig. 4, R
nthe line scan signals of row becomes high level, R
n+1the line scan signals of row becomes high level, R
nrow and R
n+1in row, the TFT of each pixel cell all opens, and now, the row control signal of column drive circuit is as the state as shown in 2. in Fig. 5, now, and switch S, S
1and S
2control signal be low level, switch S, S
1and S
2be off-state, the connection between adjacent two column data lines disconnects, and the i.e. R of current scan line
nrow and next scan line R
n+1the TFT of row all opens, R
neach pixel cell and R in row
n+1in row, between each pixel cell, carry out secondary charges and share, R
nrow and R
n+1the charges of different polarity neutralization of row storage, namely by the same R that is listed as
n+1on row, the storage capacitors of each pixel cell is given R
nthe storage capacitors of each pixel cell charging on row, so, as shown in Figure 9, obtain RN capable in magnitude of voltage in each pixel cell storage capacitors be 3V
h/ 4+V
l/ 4 or V
h/ 4+3V
l/ 4;
Step 3: the line scan signals of horizontal drive circuit output becomes as the state as shown in 3. in Fig. 4, R
nthe line scan signals of row is maintained high level, R
n+1the line scan signals of row becomes low level, R
nthe TFT of row maintains opening, R
n+1tFT on row closes, and meanwhile, the row control signal of column drive circuit becomes as state, switch S and the switch S as shown in 3. in Fig. 5
1control signal become high level, switch S
2control signal be low level, switch S and switch S
1closure, switch S
2disconnect, as shown in figure 10, the memory capacitance driving voltage that column drive circuit output self produces is to R
neach pixel cell in row is R
nin row, each pixel cell charging, obtains required voltage.
The like, according to the flow process of above-mentioned steps 1-step 3, the pixel cell of each row in liquid crystal panel in liquid crystal display is started to drive successively charging from the first row, until last column charging finishes, complete line scanning process one time, realize the driving process of liquid crystal display.
Wherein, the variation of line scan signals can realize by frequency synthesis, is that the square wave of two distinct pulse widths is synthetic, forms the synthetic square wave with distinct pulse widths driven.
Do not considering, under the prerequisite of digital power consumption and quiescent dissipation, to operate according to the method described above V
swingsize be V
hwith 3V
h/ 4+V
ldifference between/4 or V
h/ 4+3V
l/ 4 and V
lbetween difference, i.e. V
h/ 4-V
l/ 4, and V in classic method
swingsize be V
h-V
l, therefore, V
swingsize be only in classic method 1/4, in substitution formula (1), the dynamic power consumption that can obtain after electric charge is shared can reduce 75%.
The above, be only preferred embodiment of the present invention, is not intended to limit protection scope of the present invention.