The present invention relates to an LCD device and a method thereof, particularly to an LCD device and a method thereof, whereby a single-level drive monochromatic LCD panel can have gray levels.
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In the FRM technology, the gray level is determined by the ratio of turn-on cycles and turn-off cycles per second. Thus, the display time of each pixel has to increase, and light has to accumulate to a sufficient amount during the interval of vision persistence. Besides, the frequency of lightening a pixel and the frequency of the background light should not overlap lest the gray-level effect be affected.
In the PWM technology, the gray level is determined by the turn-on interval in each segment. Therefore, the original LCD drive circuit has to be replaced to adjust the output timing. In other words, the output control of the segment circuit needs a special design, which increases the complexity and cost of the circuit.
Accordingly, the present invention discloses a row-modulation gray-level LCD device and a method thereof to enable a single-level LCD drive chip and panel to have gray levels and solve the conventional problem.
The primary objective of the present invention is to provide a row-modulation gray-level LCD device and a method thereof, wherein at least two original common voltage signals and the segment voltage signals cooperate to sequentially drive the monochromatic pixels of the same row in a time-division mode, whereby the time-division turn-on and turn-off states of the monochromatic pixels enable a single-level LCD drive chip to present gray levels.
The device of the present invention comprises a monochromatic LCD panel, a single-level driver and a row-modulation device. The monochromatic LCD panel has a plurality of common electrodes and a plurality of segment electrodes; the common electrodes and the segment electrodes intersect vertically and are respectively arranged on an upper layer and a lower layer. The single-level driver sequentially generates a plurality of original common voltage signals and a plurality of segment voltage signals according to the timing. The row-modulation device has a plurality of input junctions and a plurality of output junctions. The input junctions are arranged into at least two sets, and each of the sets is electrically coupled to one of the output junctions.
The single-level driver is electrically coupled to a plurality of segment electrodes via a plurality of segment circuits and electrically coupled to the input junctions of the row-modulation device via a plurality of common circuits. The output junctions of the row-modulation device are electrically coupled to the common electrodes via a plurality of common-set circuits.
The single-level driver sequentially generates a plurality of original common voltage signals. At least two original common voltage signals input to the common electrodes in a time-division mode to generate a new common voltage signal. The voltage differences of the new common voltage signal and at least two segment voltage signals turn on or turn off the monochromatic pixel in a time-division mode. The effects of turn-on and turn-off states are accumulated by vision persistence to form gray levels.
Below, the technical contents of the present invention are described in detail in cooperation with the drawings.
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Below is described the driving method generating gray levels according to the present invention. Firstly, a monochromatic LCD panel 10, a single-level driver 20 and a row-modulation device 30, as those shown in the abovementioned embodiments, are prepared, wherein the monochromatic LCD panel 10 has a resolution of (A rows)*(D columns), and (B+1) gray levels are intended to generate. Thus, the single-level driver 20 should have a resolution of at least (C columns)*(A rows), wherein C is the product of A and B. In other words, the single-level driver 20 should sequentially generate C pieces of original common voltage signals 21 and A pieces of segment voltage signals. Further, in the row-modulation device 30, B pieces of input junctions 31 are assembled together and then outputs from one output junction 32.
Next, the single-level driver 20 is electrically coupled to a plurality of segment electrodes 12 via a plurality of segment circuits 40. Next, the single-level driver 20 is electrically coupled to a plurality of input junctions 31 of the row-modulation device 30 via a plurality of common circuits 50. Next, a plurality of output junctions 32 of the row-modulation device 30 are electrically coupled to a plurality of common electrodes 11 via a plurality of common-set circuits 51.
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In the present invention, the row-modulation device 30 inputs at least two sequentially generated original common voltage signals 21 to the common electrode 11 of the same row and generate new common voltage signals 22, and the new common voltage signals 22 cooperate with the segment voltage signals to turn on or turn off the monochromatic pixel 13 in a time-division mode, and the vision persistence accumulates the effects of turn-on cycles and turn-off cycles to present gray levels.
Distinct from the prior arts, the present invention adopts a row-modulation method to generate gray levels, which is an intermediate of the FRM technology and the PWM technology. The FRM technology is based on the overlap of frames, and the PWM technology is based on the time division of row interpolation. The present invention needn't use a conventional gray-level driving chip but needs only a conventional single-level driving chip to perform row-modulation and generate gray levels.