The present invention relates generally to a liquid crystal display (LCD), and more particularly, to an LCD panel that utilizes a column inversion data driving scheme to reduce power consumption and methods of driving same.
A liquid crystal display (LCD) device includes an LCD panel formed with liquid crystal cells and pixel elements with each associating with a corresponding liquid crystal cell and having a liquid crystal (LC) capacitor and a storage capacitor, a thin film transistor (TFT) electrically coupled with the liquid crystal capacitor and the storage capacitor. These pixel elements are substantially arranged in the form of a matrix having a number of pixel rows and a number of pixel columns. Typically, scanning signals are sequentially applied to the number of pixel rows for sequentially turning on the pixel elements row-by-row. When a scanning signal is applied to a pixel row to turn on corresponding TFTs of the pixel elements of a pixel row, source signals (i.e., image signals) for the pixel row are simultaneously applied to the number of pixel columns so as to charge the corresponding liquid crystal capacitor and storage capacitor of the pixel row for aligning orientations of the corresponding liquid crystal cells associated with the pixel row to control light transmittance therethrough. By repeating the procedure for all pixel rows, all pixel elements are supplied with corresponding source signals of the image signal, thereby displaying the image signal thereon.
Liquid crystal molecules have a definite orientational alignment as a result of their long, thin shapes. The orientations of liquid crystal molecules in liquid crystal cells of an LCD panel play a crucial role in the transmittance of light therethrough. It is known if a substantially high voltage potential is applied between the liquid crystal layer for a long period of time, the optical transmission characteristics of the liquid crystal molecules may change. This change may be permanent, causing an irreversible degradation in the display quality of the LCD panel. In order to prevent the LC molecules from being deteriorated, an LCD device is usually driven by using techniques that alternate the polarity of the voltages applied across a LC cell. These techniques may include inversion schemes such as frame inversion, row inversion, column inversion, and dot inversion. Typically, notwithstanding the inversion schemes, a higher image quality requires higher power consumption because of frequent polarity conversions. Such LCD devices, in particular thin film transistor (TFT) LCD devices, may consume significant amounts of power, which may in turn generate excessive heat. The characteristics of the LCD devices will be significantly deteriorated due to the heat generated.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.
The present invention, in one aspect, relates to an LCD panel with color washout improvement. In one embodiment, the LCD panel includes a common electrode; a plurality of scanning lines, {Gn}, n=1, 2, . . . , N, N being an integer greater than zero, spatially arranged along a row direction; a plurality of data lines, {Dm}, m=1, 2, . . . , M, M being an integer greater than zero, spatially arranged crossing the plurality of scanning lines {Gn} along a column direction perpendicular to the row direction; and a plurality of pixels, {Pn,m}, spatially arranged in the form of a matrix, each pixel Pn,m defined between two neighboring scanning lines Gn and Gn, and two neighboring data lines Dm and Dm+1. Each pixel Pn,m comprises at least a first sub-pixel, Pn,m(1), and a second sub-pixel, Pn,m(2). Each of the first sub-pixel and the second sub-pixel includes a sub-pixel electrode, a liquid crystal (LC) capacitor electrically coupled between the sub-pixel electrode and the common electrode in parallel, and a transistor having a gate, a source and a drain electrically coupled to the sub-pixel electrode.
The gate and the source of the transistor of the first sub-pixel Pn,m(1) of the pixel Pn,m are electrically coupled to the scanning line Gn, and the data line Dm, respectively, and the gate and the source of the transistor of the second sub-pixel Pn,m(2) of the pixel Pn,m are electrically coupled to the scanning line Gn and the sub-pixel electrode of the first sub-pixel Pn,m(1), respectively.
The gate and the source of the transistor of the first sub-pixel Pn+1,m(1) of the pixel Pn+1,m are electrically coupled to the scanning line Gn+1 and the sub-pixel electrode 115b of the second sub-pixel Pn+1,m(2), respectively, and the gate and the source 116s of the transistor of the second sub-pixel Pn+1,m(2) of the pixel Pn+1,m are electrically coupled to the scanning line Gn+2 and the data line Dm+1, respectively.
In one embodiment, each of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) of the pixel Pn,m further comprises a storage capacitor electrically coupled between the sub-pixel electrode and the common electrode in parallel.
Additionally, the LCD panel may have a plurality of touch sensing signal lines {Lk}, k=1, 2, . . . , K, K being an integer greater than zero. Each touch sensing signal line is arranged adjacent and parallel to a scanning line Gn or a data line Dm. In one embodiment, each pixel in the even number pixel rows of the pixel matrix or each pixel in the odd number pixel rows of the pixel matrix further comprises a photo sensor (PS) and a transistor having a gate electrically connected to one of two corresponding scanning lines defining the pixel, a source electrically connected the photo sensor and a drain electrically connected to a corresponding touch sensing signal line.
The LCD panel also has a gate driver and a data driver. The gate driver is adapted for generating a plurality of scanning signals respectively applied to the plurality of scanning lines {Gn}, where the plurality of scanning signals is configured to turn on the transistors connected to the plurality of scanning lines {Gn} in a predefined sequence. The data driver is adapted for generating a plurality of data signals respectively applied to the plurality of data lines {Dm}, where the plurality of data signals is configured such that any two neighboring data signals have inverted polarities.
In one embodiment, each of the plurality of scanning signals is configured to have a waveform. The waveform has a first voltage potential V1 in a first duration, T1, a second voltage potential V2 in a second duration, T2, a third voltage potential V3 in a third duration, T3, a fourth voltage potential V4 in a fourth duration, T4, and a fifth voltage potential V5 in a fifth duration, T5, where the (+1)-th duration Tj+1 is immediately after the j-th duration Tj, j=1, 2, 3 and 4, and V1=V3=V5>V2=V4, T2=(T1+2t), T3=(T1−t), T4=2t, T5=T1, and T1>>t. The waveform of each of the scanning signals is sequentially shifted from one another by a duration of T1+T2.
In another embodiment, each of the plurality of scanning signals is configured to have a waveform, where the waveform of each of the plurality of scanning signals has a first voltage potential V1(t) in a first duration, T1, a second voltage potential V2(t) in a second duration, T2, and a third voltage potential V3(t) in a third duration, T3. The second duration T2 is immediately after the first duration T1 and the third duration T3 is immediately after the second duration T2. V1(t) and V3(t) vary with time and V2(t)=V2 is a constant and independent of time. The first duration T1 includes a first time period, T0, and a second time period, T=(T1−T0), immediately after the first time period T0, where in the first time period T0, V1(t)=V1, a constant voltage potential, and V1(t) continuously decreases from V1 to V0 as time goes in the second time period T. The third duration T3 includes a first time period, T0, a second time period, T, immediately after the first time period T0, and a third time period (T3−T1−T0), immediately after the second time period T, where V3(t)=V3, a constant voltage potential, in the first time period T0, V3(t) continuously decreases from V3 to V0 as time goes in the second time period T, and V3(t)=V3 in the third time period, and where V1=V3>V2, V1>V0≧V2, T1=T2, and T3=2T1. The waveform of each of the scanning signals is sequentially shifted from one another by a duration of T1+T2.
In such a driving scheme, in operation, the plurality of pixels {Pn,m} has a pixel polarity that is in a dot inversion.
In one embodiment, each of the transistors is a field-effect thin film transistor (TFT).
In another aspect, the present invention relates to a method of driving a liquid crystal display (LCD). In one embodiment, the method includes the steps of providing an LCD panel. The LCD panel has a common electrode, a plurality of scanning lines, {Gn}, n=1, 2, . . . , N, N being an integer greater than zero, spatially arranged along a row direction, a plurality of data lines, {Dm}, m=1, 2, . . . , M, M being an integer greater than zero, spatially arranged crossing the plurality of scanning lines {Gn} along a column direction perpendicular to the row direction, and a plurality of pixels, {Pn,m}, spatially arranged in the form of a matrix.
Each pixel Pn,m is defined between two neighboring scanning lines Gn and Gn+1 and two neighboring data lines Dm and Dm+1, and has at least a first sub-pixel, Pn,m(1), and a second sub-pixel, Pn,m(2). Each of the first sub-pixel and the second sub-pixel comprises a sub-pixel electrode, a liquid crystal (LC) capacitor electrically coupled between the sub-pixel electrode and the common electrode in parallel, and a transistor having a gate, a source and a drain electrically coupled to the sub-pixel electrode. The gate and the source of the transistor of the first sub-pixel Pn,m(1) of the pixel Pn,m are electrically coupled to the scanning line Gn+1 and the data line Dm, respectively. The gate and the source of the transistor of the second sub-pixel Pn,m(2) of the pixel Pn,m are electrically coupled to the scanning line Gn and the sub-pixel electrode of the first sub-pixel Pn,m(1), respectively. The gate and the source of the transistor of the first sub-pixel Pn+1,m(1) of the pixel Pn+1,m are electrically coupled to the scanning line Gn+1 and the sub-pixel electrode of the second sub-pixel Pn+1,m(2), respectively. The gate and the source of the transistor of the second sub-pixel Pn+1,m(2) of the pixel Pn+1,m are electrically coupled to the scanning line Gn+2 and the data line Dmm+1, respectively.
Additionally, the LCD panel may have a plurality of touch sensing signal lines {Lk}, k=1, 2, . . . , K, K being an integer greater than zero. Each touch sensing signal line is arranged adjacent and parallel to a scanning line Gn or a data line Dm. In one embodiment, each pixel in the even number pixel rows of the pixel matrix or each pixel in the odd number pixel rows of the pixel matrix further comprises a photo sensor (PS) and a transistor having a gate electrically connected to one of two corresponding scanning lines defining the pixel, a source electrically connected the photo sensor and a drain electrically connected to a corresponding touch sensing signal line.
The method further includes the step of applying a plurality of scanning signals to the plurality of scanning lines {Gn} and a plurality of data signals to the plurality of data lines {Dm}, respectively. The plurality of scanning signals is configured to turn on the transistors connected to the plurality of scanning lines {Gn} in a predefined sequence, and the plurality of data signals is configured such that any two neighboring data signals have inverted polarities. Accordingly, the plurality of pixels {Pn,m} in operation has a pixel polarity that is in a dot inversion.
In yet another aspect, the present invention relates to a liquid crystal display (LCD) panel. In one embodiment, the LCD panel has a plurality of pixels, {Pn,m}, spatially arranged in the form of a matrix, n=1, 2, . . . , N, and m=1, 2, . . . , M, and N, M being an integer greater than zero. Each pixel Pn,m has at least a first sub-pixel, Pn,m(1) and a second sub-pixel, Pn,m(2), where each of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) comprises a sub-pixel electrode and a switching element electrically coupled to the sub-pixel electrode.
The LCD panel also has a plurality of scanning lines, {Gn}, spatially arranged along a row direction. Each pair of two neighboring scanning lines Gn and Gn+1 defines a pixel row Pn,{m} of the pixel matrix {Pn,m} therebetween and is electrically coupled to the switching elements of the first sub-pixel and the second sub-pixel of each pixel in the pixel row Pn,{m}, respectively.
The LCD panel further has a plurality of data lines, {Dm}, spatially arranged crossing the plurality of scanning lines {Gn} along a column direction perpendicular to the row direction. Each pair of two neighboring data lines Dm and Dm+1 defines a pixel column, P{n},m, of the pixel matrix {Pn,m} therebetween. Each data line Dm is electrically coupled to the switching element of the first sub-pixel or the second sub-pixel of each odd pixel of one of two neighboring pixel columns P{n},m−1 and P{n},m associated with the data line Dm and to the switching element of the second sub-pixel or the first sub-pixel of each even pixel of the other of the two neighboring pixel columns P{n},m−1 and P{n},m.
Additionally, the LCD panel may also have at least one common electrode. In one embodiment, each of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) of the pixel Pn,m of the pixel matrix {Pn,m} further comprises an LC capacitor and a storage capacitor both electrically coupled between the sub-pixel electrode and the common electrode in parallel.
Furthermore, the LCD panel has a gate driver for generating a plurality of scanning signals respectively applied to the plurality of scanning lines {Gn}, where the plurality of scanning signals is configured to turn on the switching elements connected to the plurality of scanning lines {Gn} in a predefined sequence; and a data driver for generating a plurality of data signals respectively applied to the plurality of data lines {Dm}, where the plurality of data signals is configured such that any two neighboring data signals have inverted polarities. In operation, the plurality of pixels {Pn,m} has a pixel polarity that is in a dot inversion.
In one embodiment, each of the switching elements of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(1) of the pixel Pn,m of the pixel matrix {Pn,m} is a field-effect thin film transistor having a gate, a source and a drain. In one embodiment, the drain of the transistor of each of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) of the pixel Pn,m of the pixel matrix {Pn,m} is electrically coupled to the sub-pixel electrode of the corresponding sub-pixel. The gate and the source of the transistor of the first sub-pixel Pn,m(1) of the pixel Pn,m of the pixel matrix {Pn,m} are electrically coupled to the scanning line Gn+1 and the data line Dm, respectively. The gate and the source of the transistor of the second sub-pixel Pn,m(2) of the pixel Pn,m of the pixel matrix {Pn,m} are electrically coupled to the scanning line Gn and the sub-pixel electrode of the first sub-pixel Pn,m(1), respectively. The gate and the source of the transistor of the first sub-pixel Pn+1,m(1) of the pixel Pn+1,m of the pixel matrix {Pn,m} are electrically coupled to the scanning line Gn+ and the sub-pixel electrode of the second sub-pixel Pn+1,m(2), respectively. The gate and the source of the transistor of the second sub-pixel Pn+1,m(2) of the pixel Pn+1,m of the pixel matrix {Pn,m} are electrically coupled to the scanning line Gn+2 and the data line Dm+1, respectively.
Additionally, the LCD panel may have a plurality of touch sensing signal lines {Lk}, k=1, 2, . . . , K, K being an integer greater than zero. Each touch sensing signal line is arranged adjacent and parallel to a scanning line Gn or a data line Dm. In one embodiment, each pixel in the even number pixel rows of the pixel matrix or each pixel in the odd number pixel rows of the pixel matrix further comprises a photo sensor (PS) and a transistor having a gate electrically connected to one of two corresponding scanning lines defining the pixel, a source electrically connected the photo sensor and a drain electrically connected to a corresponding touch sensing signal line.
In a further aspect, the present invention relates to a method of driving an LCD. In one embodiment, the method includes the steps of providing an LCD panel. The LCD panel in one embodiment, has a plurality of pixels, {Pn,m}, spatially arranged in the form of a matrix, n=1, 2, . . . , N, and m=1, 2, . . . , M, and N, M being an integer greater than zero. Each pixel Pn,m has at least a first sub-pixel, Pn,m(1) and a second sub-pixel, Pn,m(2). Each of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) comprises a sub-pixel electrode and a switching element electrically coupled to the sub-pixel electrode.
The LCD panel also has a plurality of scanning lines, {Gn}, spatially arranged along a row direction, and a plurality of data lines, {Dm}, spatially arranged crossing the plurality of scanning lines {Gn} along a column direction perpendicular to the row direction. Each pair of two neighboring scanning lines Gn and Gn−1 defines a pixel row Pn,{m} of the pixel matrix {Pn,m} therebetween and is electrically coupled to the switching elements of the first sub-pixel and the second sub-pixel of each pixel in the pixel row Pn,{m}, respectively. Each pair of two neighboring data lines Dm and Dm+1 defines a pixel column, P{n},m, of the pixel matrix {Pn,m} therebetween. Each data line Dm is electrically coupled to the switching element of the first sub-pixel or the second sub-pixel of each odd pixel of one of two neighboring pixel columns P{n},m−1 and P{n} m associated with the data line Dm and to the switching element of the second sub-pixel or the first sub-pixel of each even pixel of the other of the two neighboring pixel columns P{n},m−1 and P{n},m.
In one embodiment, the LCD panel further comprises at least one common electrode. Each of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) of the pixel Pn,m of the pixel matrix {Pn,m} further comprises an LC capacitor and a storage capacitor both electrically coupled between the sub-pixel electrode and the common electrode in parallel.
In one embodiment, each of the switching elements of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(1) of the pixel Pn,m of the pixel matrix {Pn,m} is a field-effect thin film transistor having a gate, a source and a drain. The drain of the transistor of each of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) of each pixel Pn,m of the pixel matrix {Pn,m} is electrically coupled to the sub-pixel electrode of the corresponding sub-pixel. The gate and the source of the transistor of the first sub-pixel Pn,m(1) of the pixel Pn,m of the pixel matrix {Pn,m} are electrically coupled to the scanning line Gn+1 and the data line Dm, respectively. The gate and the source of the transistor of the second sub-pixel Pn,m(2) of the pixel Pn,m of the pixel matrix {Pn,m} are electrically coupled to the scanning line Gn and the sub-pixel electrode of the first sub-pixel Pn,m(1), respectively. The gate and the source of the transistor of the first sub-pixel Pn+1,m(1) of the pixel Pn+1,m of the pixel matrix {Pn,m} are electrically coupled to the scanning line Gn+1 and the sub-pixel electrode of the second sub-pixel Pn+1,m(2), respectively. The gate and the source of the transistor of the second sub-pixel Pn+1,m(2) of the pixel Pn+1,m of the pixel matrix {Pn,m} are electrically coupled to the scanning line Gn+2 and the data line Dm+1, respectively.
Additionally, the LCD panel may have a plurality of touch sensing signal lines {Lk}, k=1, 2, . . . , K, K being an integer greater than zero. Each touch sensing signal line is arranged adjacent and parallel to a scanning line Gn or a data line Dm. In one embodiment, each pixel in the even number pixel rows of the pixel matrix or each pixel in the odd number pixel rows of the pixel matrix further comprises a photo sensor (PS) and a transistor having a gate electrically connected to one of two corresponding scanning lines defining the pixel, a source electrically connected the photo sensor and a drain electrically connected to a corresponding touch sensing signal line.
Furthermore, the method includes the step of applying a plurality of scanning signals to the plurality of scanning lines {Gn} and a plurality of data signals to the plurality of data lines {Dm}, respectively. The plurality of scanning signals is configured to turn on the switching elements connected to the plurality of scanning lines {Gn} in a predefined sequence, and the plurality of data signals is configured such that any two neighboring data signals have inverted polarities. Accordingly, the plurality of pixels {Pn,m} in operation has a pixel polarity that is in a dot inversion.
These and other aspects of the present invention will become apparent from the following description of the preferred embodiment taken in conjunction with the following drawings, although variations and modifications therein may be affected without departing from the spirit and scope of the novel concepts of the disclosure.
The accompanying drawings illustrate one or more embodiments of the invention and, together with the written description, serve to explain the principles of the invention. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment, wherein:
The present invention is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Various embodiments of the invention are now described in detail. Referring to the drawings, like numbers indicate like components throughout the views. As used in the description herein and throughout the claims that follow, the meaning of “a”, “an”, and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. Additionally, some terms used in this specification are more specifically defined below.
The description will be made as to the embodiments of the present invention in conjunction with the accompanying drawings in
Referring to
Furthermore, each pixel Pn,m is configured to have two or more sub-pixels. As shown in
The LC capacitor 113a of the first sub-pixel Pn,m(1) of the pixel Pn,m is electrically connected between the sub-pixel electrode 115a of the first sub-pixel Pn,m(1) of the pixel Pn,m and the common electrode 160 in parallel. The LC capacitor 113b of the second sub-pixel Pn,m(2) of the pixel Pn,m is electrically connected between the sub-pixel electrode 115b of the second sub-pixel Pn,m(2) of the pixel Pn,m and the common electrode 160 in parallel. Additionally, each of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) of the pixel Pn,m may have a storage capacitor electrically connected between the sub-pixel electrode 115a/115b of the corresponding sub-pixel Pn,m(1)/Pn,m(2) of the pixel Pn,m and the common electrode 160 in parallel (not shown), for providing coupling voltages to the corresponding LC capacitor 113a/113b to compensate for charge leakages therefrom.
The gate 112g and the source 112s of the transistor 112 of the first sub-pixel Pn,m(1) of the pixel Pn,m are electrically coupled to the scanning line Gn+1 and the data line Dm, respectively, and the gate 116g and the source 116s of the transistor 116 of the second sub-pixel Pn,m(2) of the pixel Pn,m are electrically coupled to the scanning line Gn and the sub-pixel electrode 115a of the first sub-pixel Pn,m(1), respectively.
The gate 112g and the source 112s of the transistor 112 of the first sub-pixel Pn+1,m(1) of the pixel Pn+1,m are electrically coupled to the scanning line Gn+1 and the sub-pixel electrode 115b of the second sub-pixel Pn+1,m(2), respectively, and the gate 116g and the source 116s of the transistor 116 of the second sub-pixel Pn+1,m(2) of the pixel Pn+1,m are electrically coupled to the scanning line Gn+2 and the data line Dm+1, respectively.
In one embodiment, the sub-pixel electrodes 115a/115b of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) of each pixel Pn,m are deposited on a first substrate (not shown), while the common electrode 160 is deposited on a second substrate (not shown) that is spatially apart from the first substrate. The LC molecules are filled into cells between the first and second substrates. Each cell is associated with a pixel Pn,m of the LCD panel 100. Voltages (potentials) applied to the sub-pixel electrodes control orientational alignments of the LC molecules in the LC cells associated with the corresponding sub-pixels.
The transistor 112 and the transistor 116 in one embodiment are field-effect TFTs and adapted for activating the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2), respectively. Other types of transistors may also be utilized to practice the present invention. When the transistor 112 and the transistor 116 are selected to be turned on by a scanning signal applied through the scanning line Gn or the scanning line Gn+1 to which the gate 112g of the transistor 112 and the gate 116g of the transistor 116 are electrically coupled, a data signal applied through the corresponding data line Dm or the corresponding data line Dm+1 is incorporated into the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) by means of charging the corresponding LC capacitors 113a and 113b of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2), respectively. The charged potentials of the LC capacitors 113a and 113b of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) of the pixel Pn,m are corresponding to the electrical fields applied to corresponding liquid crystal cells between the first and second substrates.
The LCD panel 100 further has a gate driver 152 and a data driver 154, as shown in
For such a pixel arrangement and a driving scheme, data of an image to be displayed is applied to the plurality of data lines {Dm} in the column inversion, while the image display in the plurality of pixels {Pn,m} is in the dot inversion, which has high quality of display. Because each data line Dm is electrically coupled to both the pixel column P{n},m and its neighboring pixel column P{n},m+1, only half number of data lines {Dm} may be needed in order to achieve the dot inversion in the LCD panel 100, comparing to that of a conventional LCD panel of the dot inversion. Accordingly, the LCD panel 100 may save as much as half of power consumption of the conventional LCD panel of the dot inversion.
Referring to
For the pixels P0,0, P0,1 and P0,2 of the first pixel row defined by the pair of two neighboring scanning lines G0 and G1, the source of the first transistor 212 of each pixel P0,0, P0,1 or P0,2 is electrically connected to a corresponding data line D0, D1 or D2, while the source of the second transistor 216 of each pixel P0,0, P0,1 or PO,2 is electrically connected to the first sub-electrode 215a of the pixel. However, for the pixels P1,0, P1,1 and P1,2 of the second pixel row defined by the pair of two neighboring scanning lines G1 and G2, the source of the first transistor 212 of each pixel P1,0, P1,1, or P1,2 is electrically connected to the second sub-electrode 215b of the pixel, while the source of the second transistor 216 of each pixel P0,0, P0,1 or P0,2 is electrically connected to a corresponding data line D1, D2 or D3. The pixel arrangement repeats in every two neighboring pixel rows, as shown in
In the exemplary embodiment, the driving signals include three scanning signals g1 (271), g2 (272) and g3 (273) respectively applied to the scanning lines G1, G2 and G3, and two data signals d1 (281) and d2 (282) respectively applied to the data lines D1 and D2, and a common signal Vcom (290) applied to the common electrode (not shown), respectively. The scanning signals 271, 272 and 273 are generated by a gate driver. Each of the scanning signals 271, 272 and 273 has a waveform 270. The waveform 270 has a first voltage potential V1 in a first duration, T1, a second voltage potential V2 in a second duration, T2, and a third voltage potential V3 in a third duration, T3, where the second duration T2 is immediately after the first duration T1, and the third duration T3 is immediately after the second duration T2. In one embodiment, as shown in
The common signal Vcom 290 has a constant potential (voltage). The data signals 281 and 282 are generated according to an image to be displayed on these pixels and have inverted polarities. That is, if the data signal 281 has a positive voltage, then the data signal 282 has a negative voltage, and vice versus. In the embodiment, the data signal 281 has a positive voltage. while the data signal 282 has a negative voltage.
As shown in
In the time period 2 of (t2−t1), the transistors 212 and 216 electrically connected to the scanning line G1 are turned on, while the transistors 212 and 216 electrically connected to the scanning lines G2 and G3 are turned off, respectively. Accordingly, a positive voltage is generated in the first sub-pixel electrode 215a of the pixel P0,1 by application of the data signal 281 to the source of the first transistor 212 of the pixel P0,1, while a negative voltage is generated in the first sub-pixel electrode 215a of the pixel P0,2 by application of the data signal 282 to the source of the first transistor 212 of the pixel P0,2. As shown in
As shown in
Accordingly, for this pixel arrangement and driving scheme, the dot inversion is achieved in the pixel matrix {Pn,m} of the LCD panel 200 for the image display, with the data inputting into the data lines in the column inversion.
However, the simplified waveform (pulses) and their timing sequence (gate timing) in the scanning signals g1, g2 and g3 as shown in
In operation, in the time period of (t1−t0), the gates G2 and G3 are turned on, i.e., the transistors 312 and 316 electrically connected to the scanning lines G2 and G3 are turned on, the sub-pixel A is charged to 4V by applying the data signal through the data line D2. At time t1, the gate G3 is turned off, which generates a first feed though in the sub-pixel A, thereby reducing A data to 3V thereafter. Meantime, the sub-pixel B is charged to 4V. Then, at time t2, the gate G2 is turned off as well, which generates a second feed through in the sub-pixel A and a first feed through in the sub-pixel B, respectively, thereby reducing A_data to 2V and B_data to 3 V, respectively, thereafter. In the time period of (t3−t2), the gates G3 and G4 are turned on, the sub-pixel C is charged to 4V. At time t3, the gate G4 is turned off, which generates a first feed though in the sub-pixel C, thereby reducing C_data to 3V thereafter. Meantime, the sub-pixel D is charged to 4V. Then, at time t4, the gate G3 is turned off as well, which generates a second feed through in the sub-pixel C and a first feed through in the sub-pixel D, respectively, thereby reducing C_data to 2V and D_data to 3 V, respectively, thereafter.
The non-uniformity of the potential voltages in the sub-pixels A and B, and C and D cause the mura effect, a defect in intensity in displayed images. In order to get rid of the mura effect, the gate timing needs being modified such that the gates are turned on and/or turned off in a predetermined order. This can be implemented by modulating the waveform of the scanning signals g1, g2, . . . , gN applied to the scanning lines G1, G2, . . . , GN, respectively.
When such scanning signals g1, g2, . . . and g5 are applied to the scanning lines G1, G2, . . . and G5, respectively, each of the four sub-pixels A, B, C and D as shown in
Similarly, the voltage potentials of the sub-pixels C and D, C_data and D_data, are also about 3V, which are identical to that of the sub-pixels A and B.
When the scanning signals g1, g2, g3 and g4 are applied to the scanning lines G1, G2, G3 and G4, respectively, of the LCD panel 300, as shown in
For the pixels P1,1, P1,2 and P1,3 of the first pixel row defined by the pair of two neighboring scanning lines G0 and G1, the source of the first transistor 512 of each pixel P1,1, P1,2 or P1,3 is electrically connected to a corresponding data line D0, D1 or D2, while the source of the second transistor 516 of each pixel P1,1, P1,2 or P1,3 is electrically connected to the first sub-electrode 515a of the pixel. However, for the pixels P2,1, P2,2 and P2,3 of the second pixel row defined by the pair of two neighboring scanning lines G1 and G2, the source of the first transistor 512 of each pixel P2,1, P2,2 or P2,3 is electrically connected to the second sub-electrode 515b of the pixel, while the source of the second transistor 516 of each pixel P1,1, P1,2 or P1,3 is electrically connected to a corresponding data line D1, D2 or D3. The pixel arrangement repeats in every two neighboring pixel rows, as shown in
In the exemplary embodiment, the driving signals include four scanning signals g0, g1 g2, and g3 respectively applied to the scanning lines G0, G1, G2 and G3. Each of the scanning signals g0, g1 g2, and g3 has a waveform 570. The waveform 570 has a first voltage potential V1 in a first duration, T1, a second voltage potential V2 in a second duration, T2, a third voltage potential V3 in a third duration, T3, a fourth voltage potential V4 in a fourth duration, T4, and a fifth voltage potential V5 in a fifth duration, T5, where the (+1)-th duration Tj+1 is immediately after the j-th duration Tj, j=1, 2, 3, and 4. In one embodiment, as shown in
The data signals d1, d2, d3 and d4 (not shown in
Accordingly, for such a pixel arrangement and driving scheme, the dot inversion is achieved in the pixel matrix {Pn,m} of the LCD panel 500 for the image display, with the data inputting into the data lines in the column inversion.
In the time period of (t1−t0), only the transistors 512 and 516 electrically connected to the scanning lines G0 and G1 are turned on, the data signal d1 is transmitted through the sub-pixels A, B and X. Eventually, the data signal d1 is delivered to the sub-pixel B (the second sub-pixel 515b of the pixel P1,2), which is indicated by symbol “+”.
In the time period of (t2−t1), none of the transistors 512 and 516 of the LCD panel 500 is turned on, thus, the data signal d1 is delivered to nowhere.
In the time period of (t3−t2), only the transistors 512 and 516 electrically connected to the scanning line G0, then the data signal d1 is delivered to the sub-pixel X.
In the time period of (t4−t3), none of the transistors 512 and 516 of the LCD panel 500 is turned on, and the data signal d1 is delivered to nowhere.
In the time period of (t5−t4), only the transistors 512 and 516 electrically connected to the scanning lines G1 and G2, the data signal d1 is transmitted through the sub-pixels A, C and D. Eventually, the data signal d1 is delivered to the sub-pixel C (the first sub-pixel P2,1(1) 515a of the pixel P2,1).
In the time period of (t6−t5), none of the transistors 512 and 516 of the LCD panel 500 is turned on, thus, the data signal d1 is delivered to nowhere.
In the time period of (t7−t6), only the transistors 512 and 516 electrically connected to the scanning line G1, thus the data signal d1 is delivered to the sub-pixel A (the first sub-pixel P1,2(1) 515a of the pixel P1,2).
In the time period of (t8−t7), none of the transistors 512 and 516 of the LCD panel 500 is turned on, thus, the data signal d1 is delivered to nowhere.
In the time period of (t9−t8), only the transistors 512 and 516 electrically connected to the scanning lines G2 and G3, the data signal d1 is transmitted through the sub-pixels D, E and F. Eventually, the data signal d1 is delivered to the sub-pixel F (the second sub-pixel P3,2(2) 515b of the pixel P3,2).
In the time period of (t10−t9), none of the transistors 512 and 516 of the LCD panel 500 is turned on, and the data signal d1 is delivered to nowhere.
In the time period of (t11−t10), only the transistors 512 and 516 electrically connected to the scanning line G2, thus the data signal d1 is delivered to the sub-pixel D (the second sub-pixel P2,1(2) 515b of the pixel P2,1).
Repeating the process for the other data signals results in the dot inversion of display in the LCD panel 500, as shown in
According to the embodiments of the present invention as disclosed above, each data line is electrically coupled its two neighboring pixel columns, and the data signals applied to the corresponding data lines have voltages of alternating polarity, i.e., the column inversion, thus, only half number of data lines may be needed in order to achieve the dot inversion in the LCD panel, comparing to that of a conventional LCD panel of the dot inversion, which may significantly reduce the power consumption.
Referring to
In one embodiment, each pixel in the even number pixel rows of the pixel matrix or each pixel in the odd number pixel rows of the pixel matrix further comprises a photo sensor (PS) and a transistor having a gate electrically connected to one of two corresponding scanning lines defining the pixel, a source electrically connected the photo sensor and a drain electrically connected to a corresponding touch sensing signal line. For example, as shown in
Similarly, when the above discussed driving signals are applied to the LCD panel 600, a dot inversion image display is achieved. Because each data line Dm is electrically coupled to both the pixel column P{n},m and its neighboring pixel column P{n},m+1, only half number of data lines {Dm} may be needed in order to achieve the dot inversion in the LCD panel 600, comparing to that of a conventional LCD panel of the dot inversion. Accordingly, the LCD panel 600 may save as much as half of power consumption of the conventional LCD panel of the dot inversion.
One aspect of the present invention provides an LCD panel having a plurality of pixels, {Pn,m}, spatially arranged in the form of a matrix, n=1, 2, . . . , N, and m=1, 2, . . . , M, and N, M being an integer greater than zero. Each pixel Pn,m has at least a first sub-pixel, Pn,m(1) and a second sub-pixel, Pn,m(2), where each of the first sub-pixel Pn,m(1) and the second sub-pixel Pn,m(2) comprises a sub-pixel electrode and a switching element electrically coupled to the sub-pixel electrode. The switching element is a field-effect thin film transistor (TFT), or the like.
The LCD panel also has a plurality of scanning lines, {Gn}, spatially arranged along a row direction. Each pair of two neighboring scanning lines Gn and Gn+1, defines a pixel row Pn,{m} of the pixel matrix {Pn,m} therebetween and is electrically coupled to the switching elements of the first sub-pixel and the second sub-pixel of each pixel in the pixel row Pn,{m}, respectively.
The LCD panel further has a plurality of data lines, {Dm}, spatially arranged crossing the plurality of scanning lines {Gn} along a column direction perpendicular to the row direction. Each pair of two neighboring data lines Dm and Dm+1 defines a pixel column, P{n},m, of the pixel matrix {Pn,m} therebetween. Each data line Dm is electrically coupled to the switching element of the first sub-pixel or the second sub-pixel of each odd pixel of one of two neighboring pixel columns P{n},m−1 and P{n},m associated with the data line Dm and to the switching element of the second sub-pixel or the first sub-pixel of each even pixel of the other of the two neighboring pixel columns P{n},m−1 and P{n},m.
Additionally, the LCD panel may have a plurality of touch sensing signal lines {Lk}, k=1, 2, . . . , K, K being an integer greater than zero. Each touch sensing signal line is arranged adjacent and parallel to a scanning line Gn or a data line Dm. In one embodiment, each pixel in the even number pixel rows of the pixel matrix or each pixel in the odd number pixel rows of the pixel matrix further comprises a photo sensor (PS) and a transistor having a gate electrically connected to one of two corresponding scanning lines defining the pixel, a source electrically connected the photo sensor and a drain electrically connected to a corresponding touch sensing signal line.
Furthermore, the LCD panel has a gate driver for generating a plurality of scanning signals respectively applied to the plurality of scanning lines {Gn}, where the plurality of scanning signals is configured to turn on the switching elements connected to the plurality of scanning lines {Gn} in a predefined sequence; and a data driver for generating a plurality of data signals respectively applied to the plurality of data lines {Dm}, where the plurality of data signals is configured such that any two neighboring data signals have inverted polarities. The plurality of pixels {Pn,m} has a pixel polarity that is in the dot inversion.
Another aspect of the present invention provides a method of driving a liquid crystal display (LCD) panel as disclosed above. The method includes the step of applying a plurality of scanning signals to the plurality of scanning lines {Gn} and a plurality of data signals to the plurality of data lines {Dm}, respectively. The plurality of scanning signals is configured to turn on the transistors connected to the plurality of scanning lines {Gn} in a predefined sequence, and the plurality of data signals is configured such that any two neighboring data signals have inverted polarities. As a result, the plurality of pixels {Pn,m} has a pixel polarity that is in the dot inversion.
In sum, the present invention, among other things, discloses a liquid crystal display (LCD) panel with power consumption reduction and methods of driving same. The LCD panel in one embodiment includes a pixel matrix, a plurality of scanning lines and a plurality of data lines. Each pair of two neighboring scanning lines defines a pixel row therebetween, and each pair of two neighboring data lines defines a pixel column therebetween. Each pixel has at least a first sub-pixel and a second sub-pixel. Each sub-pixel has a sub-pixel electrode and a switching element electrically coupled to the sub-pixel electrode. Each pair of two neighboring scanning lines is electrically coupled to the switching elements of the first sub-pixel and the second sub-pixel of each pixel in the pixel row, respectively. Each data line is electrically coupled to the switching element of the first sub-pixel or the second sub-pixel of each odd pixel of one of two neighboring pixel columns associated with the data line and to the switching element of the second sub-pixel or the first sub-pixel of each even pixel of the other of the two neighboring pixel columns. The LCD panel further includes a gate driver and a data driver for generating scanning signals and data signals applied to the plurality of scanning lines and the plurality of data lines, respectively. The scanning signals are configured to turn on the switching elements connected to the plurality of scanning lines in a predefined sequence, and the data signals are configured such that any two neighboring data signals have inverted polarities.
The foregoing description of the exemplary embodiments of the invention has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.
The embodiments were chosen and described in order to explain the principles of the invention and their practical application so as to activate others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.
Number | Name | Date | Kind |
---|---|---|---|
7061478 | Moyer | Jun 2006 | B1 |
7260494 | Weiss | Aug 2007 | B2 |
7289095 | Park et al. | Oct 2007 | B2 |