1. Field of the Invention
The present invention relates to a display, and more particularly to a display including a pixel portion.
2. Description of the Background Art
A liquid crystal display including a pixel portion having a liquid crystal is known in general as a display. In this conventional liquid crystal display, a liquid crystal layer of the pixel portion is interposed between a pixel electrode and common electrode. In the conventional liquid crystal display, controlling a voltage (video signal) applied between the both electrodes of the pixel portion varies the arrangement of liquid crystal molecules, thus, a display portion displays an image based on the video signal.
In the aforementioned liquid crystal display, if a direct-current voltage is applied to the liquid crystal of the pixel portion (pixel electrode) for a long time, image persistence, so-called image burn-in, occurs. Accordingly, when the liquid crystal display is driven, it is necessary to use a drive method that inverts a voltage supply source of the pixel electrode (pixel voltage supply source) relative to a voltage supply source of the common electrode at a prescribed period. There is a DC drive method that applies a direct-current voltage to the common electrode as one example of such a drive method for a liquid crystal display. A line inversion drive method that inverts the pixel voltage supply source relative to the voltage supply source of the common electrode to which a direct-current voltage is applied at every one horizontal period is known as this DC drive method. This is disclosed in “EKISHO DISPLAY KOGAKU NYUMON” (SUZUKI, Yasoji, The Nikkan Kogyo Shimbun, Ltd., 20 Nov. 1998, pp. 101-103), for example. In addition, one horizontal period is a period where writing of video signals to all the pixel portions arranged along one gate line is completed.
However, in the case where a liquid crystal display is driven by the conventional line inversion drive method shown in
Accordingly, a liquid crystal display which employs a dot inversion drive method that inverts the pixel voltage supply source (video signal) VIDEO relative to the voltage supply source of the common electrode COM for every pixel portion in the pixel portions A to F adjacent to each other is proposed.
However, in the conventional dot inversion drive method shown in
The present invention is aimed at solving the above problems, and it is one object of the present invention to provide a display capable of making flicker difficult to be observed and of reducing power consumption.
To achieve the above object, a display according to one aspect of the present invention comprises a plurality of drain and gate lines which are arranged so as to intersect each other; first and second pixel portions, each of which includes subsidiary capacitances having a first electrode which is connected to a pixel electrode and a second electrode; first and second subsidiary capacitance lines which are connected to the second electrodes of the subsidiary capacitances of the first and second pixel portions, respectively; and a signal providing circuit including a plurality of signal providing circuit portions which provide a first signal with a first voltage supply source and a second signal with a second voltage supply source to the first subsidiary capacitance line of said first pixel portion and the second subsidiary capacitance line of said second pixel portion, respectively.
In the display according to this aspect of the present invention, the above signal providing circuit is provided. Accordingly, in the case where the first and second voltage supply sources are H and L levels, and the first and second signals are provided to the first and second subsidiary capacitance lines of the first and second pixel portions, respectively, the first signal of H level is provided to the second electrode of the subsidiary capacitance of the first pixel portion through the first subsidiary capacitance line. Thus, the voltage supply source of the subsidiary capacitance of the first pixel portion can go up to H level. In addition, the second signal of L level is provided to the second electrode of the subsidiary capacitance of the second pixel portion through the second subsidiary capacitance line, thus, the voltage supply source of the subsidiary capacitance of the second pixel portion can drop to L level. Therefore, after writing of video signal of H level to the first pixel portion is completed, when the first signal of H level is provided to the second electrode of the subsidiary capacitance of the first pixel portion, the voltage supply source of the pixel electrode of the first pixel portion can be higher than the state right after writing of video signal is completed. Therefore, after writing of video signal of L level to the second pixel portion is completed, when the second signal of L level is provided to the second electrode of the subsidiary capacitance of the second pixel portion, the pixel voltage supply source of the second pixel portion can be lower than the state right after writing of video signal is completed. Since the voltage of video signal is not necessary to be large, it is possible to easily keep increase of power consumption due to increase of the voltage of video signal in check. As a result, power consumption can be reduced. Furthermore, in the case where dot inversion drive, in which the pixel voltage supply source (video data) is inverted for each of pixel portions adjacent to each other relative to a voltage supply source of a common electrode, is used, arranging the first and second pixel portions adjacent to each other can easily achieve dot inversion drive. Moreover, in the case where block inversion drive, in which the pixel voltage supply source (video data) is inverted for every two or more of pixel portions relative to the voltage supply source of the common electrode, is used, one block includes only a plurality of first pixel portions, another block includes only a plurality of second pixel portions, and the one, and another blocks are arranged adjacent to each other. This can easily achieve block inversion drive. In dot or block inversion drive, flicker does not appear in a line shape, dissimilarly to line inversion drive that inverts the pixel voltage supply source (video data) for each of gate lines adjacent to each other relative to a voltage supply source of a common electrode, therefore, it is easy to make flicker difficult to be observed.
Embodiments of the present invention are now described with reference to the drawings.
With reference to
Each of the pixel portions 3a and 3b includes a liquid crystal layer 31, an n-channel transistor 32 and a subsidiary capacitance 33. The liquid crystal layer 31 of each of the pixel portions 3a and 3b is interposed between a pixel electrode 34 and a common counter electrode (common electrode) 35.
The drain of the n-channel transistor 32 of the pixel portion 3a is connected to the drain line D1. The drain of the n-channel transistor 32 of the pixel portion 3b is connected to the drain line D2. The sources of the pixel portions 3a and 3b are connected to the pixel electrodes 34, respectively.
One electrode 36 of the subsidiary capacitance 33 of each of the pixel portions 3a and 3b is connected to each pixel electrode 34. Another electrode 37a of the subsidiary capacitance 33 of the pixel portion 3a is connected to a subsidiary capacitance line SC1-1. Another electrode 37b of the subsidiary capacitance 33 of the pixel portion 3b is connected to a subsidiary capacitance line SC2-1. The electrode 36 is an example of a “first electrode” in the present invention. The electrodes 37a and 37b are examples of a “second electrode” in the present invention. The subsidiary capacitance line SC1-1 is an example of a “first subsidiary capacitance line” in the present invention. The subsidiary capacitance line SC2-1 is an example of a “second subsidiary capacitance line” in the present invention.
N-channel transistors (H switches) 4a and 4b, and an H-driver 5 for driving (scanning) the drain lines D1 and D2 and drain lines of a third stage and later (not shown) are provided on the circuit board 1. The n-channel transistor 4a corresponding to the pixel portion 3a (drain line D1) is connected to a video signal line VIDEO1. The n-channel transistor 4b corresponding to the pixel portion 3b (drain line D2) is connected to a video signal line VIDEO2. A V-driver 6 for driving (scanning) the gate line G1 of a first stage of and gate lines after a second stage and later (not shown in
In the first embodiment, a signal providing circuit 7 and a shift register 8 are provided on the circuit board 1. Both the subsidiary capacitance line SC1-1 corresponding to the pixel portion 3a and the subsidiary capacitance line SC2-1 corresponding to the pixel portion 3b are connected to the signal providing circuit 7 (signal providing circuit portion 7a). The signal providing circuit 7 serves to alternately provide one of an H-level side signal VSCH and an L-level side signal VSCL to the subsidiary capacitance line SC1-1, and alternately provide the other of them to the subsidiary capacitance line SC2-1, for every one frame period. One frame period is a period where writing of signals to all the pixel portions 3a and 3b, which constitute the display portion 2, is completed. The shift register 8 serves to drive the signal providing circuit 7 so that the signals from the signal providing circuit 7 are sequentially provided to a pair of subsidiary capacitance lines SC1-1 and SC2-1 along the gate line G1 of the first stage thorough a pair of subsidiary capacitance lines along a gate line of the last stage (not shown). The shift register 8 is an example of a “second shift register” in the present invention.
A driver IC 9 is provided external of the circuit board 1. A higher voltage supply source HVDD, a lower voltage supply source HVSS, a start signal STH, and a clock signal CKH are provided from the driver IC 9 to the H-driver 5. A higher voltage supply source VVDD, a lower voltage supply source VVSS, a start signal STV, a clock signal CKV, and an enable signal ENB are provided from the driver IC 9 to the V-driver 6. A higher voltage supply source VSCH, a lower voltage supply source VSCL, and a clock signal CKVSC are provided from the driver IC 9 to the signal providing circuit 7. The same signals as the signals provided to the V-driver 6 are provided from the driver IC 9 to the shift register 8.
With reference to
Output signals of the shift register circuit portions 61a and 61b, and the enable signal ENB are provided to the input terminals of the AND circuit portion 62a. Output signals of the shift register circuit portions 61b and 61c, and the enable signal ENB are provided to the input terminals of the AND circuit portion 62b. In the AND circuit portion 62c or later, output signals of the shift register circuit portions of two stages that are shifted one stage each are similarly provided thereto. Each of the AND circuit portions 62a to 62e provides a signal of H level only when the three input signals are all H levels, and provide a signal of L level when at least one of the three input signals is L level. The output terminals of the AND circuit portions 62a to 62e are connected to the gate lines G1 to G5, respectively. Although not illustrated, a level shifter circuit is connected between the AND circuit portion and the gate line.
The signal providing circuit 7 includes signal providing circuit portions 7a to 7d. The signal providing circuit portions 7a to 7d are provided so as to correspond to the gate lines G1 to G4, respectively. The signal providing circuit portion corresponding to the gate line G5 is not shown for ease of illustration.
In the circuit constitution, specifically, the signal providing circuit portion 7a is constituted of inverters 71a to 71c, clocked inverters 72a and 72b, and switches 73a to 73d, as shown in
An output signal from the shift register 8 (see
The higher voltage supply source VSCH and the lower voltage supply source VSCL are provided to the input terminals A of the switches 73a and 73d, and the input terminals A of the switches 73b and 73c, respectively. The output terminals X of the switches 73a and 73b, and the output terminals X of the switches 73c and 73d are connected to the subsidiary capacitance lines SC1-1 and SC2-1, respectively. The gates of the n-channel transistors of the switches 73a and 73c are connected to the node ND1. The gates of the p-channel transistors of the switches 73a and 73c are connected to the node ND2. The gates of the n-channel transistors of the switches 73b and 73d are connected to the node ND2. The gates of the p-channel transistors of the switches 73b and 73d are connected to the node ND1.
In addition, the signal providing circuit portions 7b to 7d shown in
As shown in
Output signals of the shift register circuit portions 81b and 81c, and the enable signal ENB are provided to the input terminals of the AND circuit portion 82a. In the AND circuit portion 82b or later, output signals of the shift register circuit portions of two stages that are shifted one stage each are similarly provided thereto. The output terminals of the AND circuit portions 82a to 82d are connected to the signal providing circuit portions 7a to 7d, respectively. In addition, the shift register 8 is not provided with an AND circuit portion, to which output signals of the shift register circuit portions 81a and 81b are provided, dissimilarly to the V-driver 6. The reason is as follows. That is, the same start signal STV, clock signal CKV, and enable signal ENB as the V-driver 6 are provided to the shift register 8. Accordingly, in order to vary the voltage supply source of the subsidiary capacitances of first stage after writing of video signals to the pixel portions of first stage is completed, it is necessary to vary the voltage supply source of the subsidiary capacitances of first stage based on the signal of H level of AND circuit portion of second stage. For this reason, such an AND circuit portion of first stage, to which the output signal of the shift register circuit portions 81a and 81b are provided, is not necessary.
The operation of the liquid crystal display according to the first embodiment is now described with reference to FIGS. 1 to 6.
First, as shown in
Next, when the clock signal CKV1 becomes H level again, signals of H level are provided from the shift register circuit portion 61c to the AND circuit portions 62b and 62c. Subsequently, when the enable signal ENB becomes H level again, all of the three signals (the signals of the shift register circuit portions 61b and 61c, and the enable signal ENB) provided to the AND circuit portion 62b become H level. Accordingly, a signal of H level is provided from the AND circuit portion 62b to the gate line G2. After that, when the enable signal ENB becomes L level, a signal of L level is provided from the AND circuit portion 62b to the gate line G2, and it is held at L level during one frame period. Then, the clock signal CKV1 becomes L level.
After that, signals of H level from the shift register circuit portions 61d to 61f are sequentially provided to the AND circuit portions 62c to 62e in synchronization with the clock signals CKV1 and CKV2 similarly to the aforementioned AND circuit portions 62a and 62b. Accordingly, signals of H level from the AND circuit portions 62c to 62e are sequentially provided to the gate lines G3 to G5 in synchronization with the enable signal ENB similarly to the aforementioned gate lines G1 and G2. Subsequently, signals of L level from the AND circuit portions 62c to 62e are sequentially provided to the gate lines G3 to G5 in synchronization with the enable signal ENB, and they are held at L level during one frame period. In addition, as shown in
In the shift register 8 (AND circuit portions 82a-82d) (see
Signals of H level sequentially provided from the shift register 8 are sequentially provided to the signal providing circuit portions 7a to 7d of the signal providing circuit 7 (see
In the signal providing circuit portion 7a, as shown in
When the input signal from the shift register 8 becomes L level, the clocked inverter 72a turns to OFF state. However, since the clocked inverter 72b turns to ON state, a signal of L level is continuously provided to the input terminal A of the inverter 71b. As a result, since the nodes ND1 and ND2 are held at H level and L level, respectively, the signal VSCH of the H-level side and the signal VSCL of the L-level side are continuously provided to the subsidiary capacitance lines SC1-1 and SC2-1, respectively. In addition, the signal providing circuit portions 7b to 7d shown in
Accordingly, the subsidiary capacitance lines SC1-1 to SC1-4 and the subsidiary capacitance lines SC2-1 to SC2-4 are sequentially provided with the signal VSCH of the H-level side and the signal VSCL of the L-level side from the signal providing circuit portions 7a to 7d with timing similar to providing signals of H level to the gate lines G2 to G5. The subsidiary capacitance lines SC1-2, SC1-3, and SC1-4 are examples of the “first subsidiary capacitance line” in the present invention. The subsidiary capacitance lines SC2-2, SC2-3, and SC2-4 are examples of the “second subsidiary capacitance line” in the present invention.
For example, the display portion 2 shown in
At this time, in the pixel portion 3a, when the n-channel transistor 32 turns to ON state, a video signal of H-level side is written to the pixel portion 3a. That is, as shown in
In this embodiment, after a signal provided to the gate line G1 becomes L level, the signal VSCH of H-level side is provided to the subsidiary capacitance line SC1-1. Thus, the signal VSCH of H-level side is provided to another electrode 37a of the subsidiary capacitance 33 (see
In the pixel portion 3b (see
The pixel portions arranged along the gate lines G2 to G5 of second stage and later (see
Next, the clock signal CKVSC provided to the signal providing circuit 7 is switched to L level. In this case, as shown in
Accordingly, in a second frame, the pixel portion 3a operates as shown in
In the first embodiment, as mentioned above, the signal providing circuit 7, which includes the signal providing circuit portions 7a-7d for providing the signal VSCH of H-level side and the signal VSCL of L-level side, is provided for the subsidiary capacitance lines SC1-1 to SC1-4 of pixel portion 3a. Accordingly, the voltage supply source of the subsidiary capacitance 33 of the pixel portion can be set to an arbitrary level, for example. In addition, after writing of video signal to the pixel portion is completed, when a desired signal is provided to the electrode of the subsidiary capacitance 33 of pixel portion, the pixel voltage supply source of the pixel portion can be varied from the state right after writing of video signal is completed. Consequently, since it is not necessary to increase a voltage of video signal, power consumption can be reduced. Additionally, the pixel portions 3a and 3b are arranged adjacent to each other, thus, it is possible to easily perform dot inversion drive. Dissimilarly to line inversion drive, in this case, flicker does not appear in a line shape. As a result, flicker can be difficult to be observed.
Furthermore, in -the first embodiment, the signal providing circuit portions 7a to 7d are provided so as to correspond to the gate lines G1 to G4, respectively. Accordingly, when video signals are sequentially written to the respective gate lines G1 to G5 of the pixel portions 3a and 3b, the respective signal providing circuit portions 7a to 7d can subsequently provide one and the other of the signal VSCH of H-level side and the signal VSCL of L-level side to the subsidiary capacitance lines SC1-1 to 1-4 and the subsidiary capacitance lines SC2-1 to 2-4 corresponding to the respective gate lines G1 to G4.
Moreover, in the first embodiment, switching is performed so that one of the signal VSCH of H-level side and the signal VSCL of L-level side is alternatively provided to the subsidiary capacitance lines SC1-1 to 1-4, and the other of them is alternatively provided to the subsidiary capacitance lines SC2-1 to 2-4, for every one frame period, thus, the voltage supply sources of video signals to be written to the pixel portions 3a and 3b are inverted relative to the voltage supply source COM of the common electrode 35 for every one frame period. Therefore, it is possible to perform dot inversion drive more easily. In this case, image persistence (image burn-in) can be easily kept in check.
With reference to
In a liquid crystal display according to this second embodiment, as shown in
In the second embodiment, the signal providing circuit 17 includes signal providing circuit portions 17a to 17c. Each of the signal providing circuit portions 17a to 17c is provided for every two stages of gate lines. Specifically, signal providing circuit portions 17a, 17b and 17c are provided so as to correspond to pairs of gate lines G1 and G2, G3 and G4, and G5 and G6, respectively. The signal providing circuit portion corresponding to the gate line G7 is not shown for ease of illustration.
In the circuit constitution of the signal providing circuit portion 17a, specifically, as shown in
As shown in
Output signals of the shift register circuit portions 181c and 181d, and the enable signal ENB are provided to the input terminals of the AND circuit portion 182a. Output signals of the shift register circuit portions 181e and 181f, and the enable signal ENB are provided to the input terminals of the AND circuit portion 182b. Output signals of the shift register circuit portions 181g and 181h, and the enable signal ENB are provided to the input terminals of the AND circuit portion 182c. The output terminals of the AND circuit portions 182a to 182c are connected to the signal providing circuit portions 17a to 17c, respectively. In addition, the shift register 18 is not provided with AND circuit portions, to which output signals of the shift register circuit portions 181a and 181b and the shift register circuit portions 181b and 181c are provided, dissimilarly to the V-driver 6. In addition, AND circuit portions, to which output signals of the shift register circuit portions 181d and 181e and the shift register circuit portions 181f and 181g are provided, are not provided. The reason is that, since the same start signal STV, clock signal CKV, and enable signal ENB as the V-driver 6 are provided to the shift register 18, such an AND circuit portion of first stage, to which the output signal of the shift register circuit portions 181a and 181b are provided, is not necessary, similarly to the foregoing first embodiment. Additionally, in this second embodiment, since subsidiary capacitance lines corresponding to two stages are connected to one signal providing circuit portion, only one AND circuit portion is also connected for subsidiary capacitance lines corresponding to each two stages. Accordingly, AND circuit portions, to which the output signals of the shift register circuit portions 181b and 181c, the shift register circuit portions 181d and 181e, and the shift register circuit portions 181f and 181g are provided, is not necessary.
The operation of the display according to the second embodiment is now described with reference to FIGS. 7 to 9. Description of parts similar to the first embodiment is omitted.
First, as shown in
In the shift register 18 (see
Next, when the clock signal CKV1 becomes H level again, a signal of H level is provided from the shift register circuit portion 181c to the AND circuit portion 182a. After that, when the clock signal CKV1 becomes L level, and the clock signal CKV2 becomes H level again, a signal of H level is provided from the shift register circuit portion 181d to the AND circuit portion 182a. Subsequently, when the enable signal ENB becomes H level, a signal of H level is provided from the AND circuit portion 182a. After that, the enable signal ENB becomes L level, thus, a signal of L level is provided from the AND circuit portion 182a, and the signal of L level is held at L level during one frame period. Then, the clock signal CKV2 becomes L level.
Similarly, when the clock signal CKV1 becomes H level again, a signal of H level is provided from the shift register circuit portion 181e to the AND circuit portion 182b. Then, when the clock signal CKV2 becomes H level again, a signal of H level is provided from the shift register circuit portion 181f to the AND circuit portion 182b. Subsequently, when the enable signal ENB becomes H level, a signal of H level is provided from the AND circuit portion 182b. After that, the enable signal ENB becomes L level, thus, a signal of L level is provided from the AND circuit portion 182b, and the signal of L level is held at L level during one frame period. Then, the clock signal CKV2 becomes L level.
After that, similarly to the aforementioned AND circuit portions 182a and 182b, signals of H level from the shift register circuit portions 181g and 181h are provided to the AND circuit portion 182c in synchronization with the clock signals CKV1 and CKV2, and a signal of H level is provided from the AND circuit portion 182c in synchronization with the enable signal ENB. Accordingly, signals of H level are sequentially provided from the shift register 18 for every two stages of gate lines. In addition, in signals of H level provided from the shift register 18, the signals provided from the AND circuit portions 182a to 182c are provided with timing similar to providing signals of H level to the gate lines G3, G5 and G7.
Signals of H level sequentially provided from the shift register 18 are sequentially provided to the signal providing circuit portions 17a to 17c of the signal providing circuit 17 (see
Accordingly, the signal VSCH of H-level side and the signal VSCL of L-level side from the signal providing circuit portions 17a to 17c are sequentially provided to the subsidiary capacitance lines SC1-1 to SC1-3 and the subsidiary capacitance lines SC2-1 to SC2-3 corresponding to two stages, respectively, with timing similar to providing signals of H level to the gate lines G3, G5 and G7.
In addition, operation performed in the display portion (not shown) of the second embodiment is similar to the foregoing first embodiment.
In the second embodiment, as mentioned above, the signal providing circuit portions 17a to 17c are provided so as to correspond to two stages of the gate lines G1 and G2 (2 lines), two stages of the gate lines G3 and G4, and two stages of the gate lines G5 and G6, respectively. Accordingly, the number of signal providing circuit portions can be reduced as compared with the case where one signal providing circuit portion is provided so as to correspond to each of a plurality of stages of gate lines (a plurality of lines). Therefore, it is possible to reduce a circuit scale and to improve yield.
In addition, the other effects in the second embodiment are similar to the foregoing first embodiment.
With reference to
In a liquid crystal display according to this third embodiment, as shown in
In the third embodiment, a shift register 28 includes four shift register circuit portions 281a to 281d. That is, the number of the shift register circuit portions (281a to 281d), which constitute the shift register 28, is half the number of shift register circuit portions (61a to 61h), which constitute the V-driver 6. The shift register 28 is an example of the “second shift register” in the present invention. These shift register circuit portions 281a to 281d have circuit constitution similar to the shift register circuit portions 61a to 61d of the V-driver 6, respectively. In addition, the shift register 28 includes AND circuit portions 282a to 282c, each of which has three input terminals and one output terminal.
Output signals of the shift register circuit portions 281a and 281b, and an enable signal ENB2 are provided to the input terminals of the AND circuit portion 282a. Output signals of the shift register circuit portions 281b and 281c, and the enable signal ENB2 are provided to the input terminals of the AND circuit portion 282b. Output signals of the shift register circuit portions 281c and 281d, and the enable signal ENB2 are provided to the input terminals of the AND circuit portion 282c. The output terminals of the AND circuit portions 282a to 282c are connected to the signal providing circuit portions 17a to 17c, respectively. The periods of start signal STV2, clock signal CKV2-1/2-2, and enable signal ENB2 for driving the shift register 28 is double the periods of start signal STV1, clock signal CKV1-1/1-2, and the enable signal ENB1 for the driving V-driver 6.
The operation of the display according to the third embodiment is now described with reference to
First, as shown in
In the shift register 28 (see
Next, signals of H level are provided from the AND circuit portions 282b and 282c in synchronization with the clock signals CKV2-1 and CKV2-2 similarly to the aforementioned AND circuit portion 282a. Accordingly, signals of H level are sequentially provided from the shift register 28. In addition, in signals of H level provided from the shift register 28, the signals provided from the AND circuit portions 282a to 282c are provided with timing similar to providing signals of H level to the gate lines G3, G5 and G7.
Signals of H level sequentially provided from the shift register 28 are sequentially provided to the signal providing circuit portions 17a to 17c of the signal providing circuit 17 (see
Accordingly, similarly to the foregoing second embodiment, the signal VSCH of H-level side and the signal VSCL of L-level side from the signal providing circuit portions 17a to 17c are sequentially provided to the subsidiary capacitance lines SC1-1 to SC1-3 and the subsidiary capacitance lines SC2-1 to SC2-3 corresponding to two stages, respectively, with timing similar to providing signals of H level to the gate lines G3, G5 and G7.
In addition, operation performed in the display portion (not shown) of the third embodiment is similar to the foregoing first embodiment.
In the third embodiment, as mentioned above, the periods of start signal STV2, clock signal CKV2-1/2-2, and enable signal ENB2 for driving the shift register 28 is double the periods of start signal STV1, clock signal CKV1-1/1-2, and enable signal ENB1 for the driving V-driver 6. Thus, the number of the shift register circuit portions (281a to 281d), which constitute the shift register 28, can be reduced to half the number of the shift register circuit portions (61a to 61h), which constitute the V-driver 6. Accordingly, the number of the shift register circuit portions can be reduced as compared with the foregoing second embodiment. Therefore, it is possible to reduce a circuit scale and to improve yield.
In addition, the other effects in the third embodiment are similar to the foregoing first embodiment.
With reference to
In this fourth embodiment, as shown in
With reference to
Output signals of the shift register circuit portions 461a and 461b, and the enable signal ENB are provided to the input terminals of the AND circuit portion 462a. In the AND circuit portion 462b or later, output signals of the shift register circuit portions of two stages that are shifted one stage each are similarly provided thereto. The output terminals of the AND circuit portions 462a to 462e are connected to the gate lines G1 to G5, respectively.
In the fourth embodiment, as described above, the signal providing circuit 47 is installed in the V-driver 46. The signal providing circuit 47 includes signal providing circuit portions 47a to 47d. The signal providing circuit portions 47a to 47d are provided so as to correspond to the gate lines G1 to G4, respectively. The signal providing circuit portion corresponding to the gate line G5 is not shown for ease of illustration.
The circuit constitution of the signal providing circuit portion 47a is similar to the signal providing circuit portion 7a of the first embodiment shown in
In this fourth embodiment, the V-driver 46 with the signal providing circuit 47 installed therein is driven with a timing chart similar to that of V-driver 6, signal providing circuit 7 and shift register 8 of the first embodiment shown in
In the fourth embodiment, as mentioned above, the signal providing circuit 47 is installed in the V-driver 46, and the signal providing circuit portions 47a to 47d are sequentially driven by using signals for sequentially driving the gate lines G2 to G5. A shift register for sequentially driving the signal providing circuit portions 47a to 47d is not necessary to be provided separately from the V-driver 46 for sequentially driving the gate lines G1 to G5. Therefore, it is possible to further reduce a circuit scale and to further improve yield as compared with the foregoing third embodiment.
In this fourth embodiment, the signal providing circuit portion corresponding to the gate line of a prescribed stage is provided with an output signal of the AND circuit portion whose output terminal is connected to the gate line of the subsequent stage, thus, the signal providing circuit portion corresponding to the gate line of the prescribed stage is driven. Accordingly, an output signal from the shift register circuit portion of the stage subsequent to the prescribed stage is provided after an output signal of the shift register circuit portion for driving the gate line of the prescribed stage is provided. Therefore, one and the other of the signal VSCH of H-level side and the signal VSCL of L-level side can be provided to one pair of the subsidiary capacitance lines, respectively, after writing of video signals to the pixel portions arranged along the gate line of the prescribed stage is completed.
It should be appreciated, however, that the embodiments described above are illustrative, and the invention is not specifically limited to description above. The invention is defined not by the foregoing description of the embodiments, but by the appended claims, their equivalents, and various modifications that can be made without departing from the scope of the invention as defined in the appended claims.
For example, in the foregoing first to fourth embodiments, the signal providing circuit portions have circuit constitution shown in
In each of the foregoing first to fourth embodiments, the pixel portions 3a and 3b are arranged adjacent to each other whereby achieving dot inversion drive. However, the present invention is not limited to this arrangement. One block may include only a plurality of pixel portions 3a, another block may include only a plurality of pixel portions 3b, and the one, and another blocks may be arranged adjacent to each other, whereby achieving block inversion drive.
In each of the foregoing first to fourth embodiments, the n-channel transistors for driving the drain lines sequentially turn to ON state, however, the present invention is not limited to this. All the n-channel transistors for the driving drain lines may simultaneously turn to ON state.
In each of the foregoing first to third embodiments, a plurality of the signal providing circuit portions are sequentially driven by using the shift register including the shift register circuit portions, which have circuit constitution similar to the shift register circuit portions of the V-driver. However, the present invention is not limited to this constitution. A shift register including shift register circuit portions, which have circuit constitution dissimilar to the shift register circuit portions of the V-driver, may be used as long as a plurality of signal providing circuit portions can be sequentially driven.
In each of the foregoing first to third embodiments, one and the other of the signal VSCH of H-level side and the signal VSCL of L-level side are provided to at least one pair of the subsidiary capacitance lines corresponding to the gate lines of a prescribed stage, respectively, with timing similar to writing of video signals to the pixel portions arranged along the gate line subsequent to the prescribed stage. However, the present invention is not limited to this timing. Timing of providing a prescribed signal to at least one pair of the subsidiary capacitance lines corresponding to the gate lines of a prescribed stage may not be same as timing of writing of video signals to the pixel portions arranged along the gate line of the subsequent stage.
In each of the foregoing second and third embodiments, one signal providing circuit portion is provided for every two stages of the gate lines, however, the present invention is not limited to this. One signal providing circuit portion may be provided for every three or more stages of the gate lines.
Number | Date | Country | Kind |
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JP 2003-393285 | Nov 2003 | JP | national |
The priority application number JP2003-393285 upon which this patent application is based is hereby incorporated by reference.