Driving method and display device utilizing the same

A display device including a gate driver, a data driver and a plurality of sub-pixels is disclosed. The gate driver sequentially asserts a first scan signal and a second scan signal. The data driver provides a first data signal and a second data signal. When the first scan signal is asserted, the first scan signal and the first data signal respond with a first response signal. When the second scan signal is asserted, the second scan signal and the second data signal respond with a second response signal. The pulse of the first response signal is different from the pulse of the second response signal. A first sub-pixel among the sub-pixels displays a first color according to the first response signal. A second sub-pixel among the sub-pixels displays a second color according to the second response signal, and the first color is different from the second color.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application claims priority of Taiwan Patent Application No. 098116516, filed on May 19, 2009, the entirety of which is incorporated by reference herein.

BACKGROUND

1. Technical Field

The disclosure relates to a display device and a driving method, and more particularly to a chromatic display device and a driving method thereof.

2. Description of the Related Art

Because cathode ray tubes (CRTs) are inexpensive and provide high definition, they are utilized extensively in televisions and computers. With technological development, new flat-panel displays are continually being developed. When a larger display panel is required, the weight of the flat-panel display does not substantially change when compared to CRT displays. Thus, flat-panel displays are widely used in the market.

SUMMARY

Display devices are provided. An exemplary embodiment of a display device comprises a gate driver, a data driver and a plurality of sub-pixels. The gate driver provides a first scan signal and a second scan signal and sequentially asserts the first and the second scan signals. The data driver provides a first data signal and a second data signal. When the first scan signal is asserted, the first scan signal and the first data signal respond with a first response signal. When the second scan signal is asserted, the second scan signal and the second data signal respond with a second response signal. The pulse of the first response signal is different from the pulse of the second response signal. A first sub-pixel among the sub-pixels displays a first color according to the first response signal. A second sub-pixel among the sub-pixels displays a second color according to the second response signal, and the first color is different from the second color.

Another exemplary embodiment of a display device comprises a gate driver, a data driver and a plurality of sub-pixels. The gate driver provides a scan signal. The data driver provides a first data signal and a second data signal. The scan signal and the first data signal respond with a first response signal. The scan signal and the second data signal respond with a second response signal. The pulse of the first response signal is different from the pulse of the second response signal. A first sub-pixel among the sub-pixels displays a first color according to the first response signal. A second sub-pixel among the sub-pixels displays a second color according to the second response signal. The first color is different from the second color.

Driving methods are provided. An exemplary embodiment of a driving method is described in the following. A first scan signal and a second scan signal are sequentially asserted. A first data signal is provided when the first scan signal is asserted. The first scan signal and the first data signal respond with a first response signal. A second data signal is provided when the second scan signal is asserted. The second scan signal and the second data signal respond with a second response signal. The pulse of the first response signal is different from the pulse of the second response signal. The first response signal is provided to a first sub-pixel among a plurality of sub-pixels. The first sub-pixel displays a first color. The second response signal is provided to a second sub-pixel among a plurality of sub-pixels. The second sub-pixel displays a second color. The first color is different from the second color.

Another exemplary embodiment of a driving method is described in the following. A scan signal is provided. A first response signal is responded according to the scan signal and a first data signal. A second response signal is responded according to the scan signal and a second data signal. The pulse of the first response signal is different from the pulse of the second response signal. The first response signal is provided to a first sub-pixel among a plurality of sub-pixels. The first sub-pixel displays a first color. The second response signal is provided to a second sub-pixel among a plurality of sub-pixels. The second sub-pixel displays a second color and the first color is different from the second color.

DETAILED DESCRIPTION

The following description is of the contemplated mode of carrying out the disclosure. This description is made for the purpose of illustrating the general principles of the disclosure and should not be taken in a limiting sense. The scope of the disclosure is determined by reference to the appended claims.

FIG. 1is a schematic diagram of an exemplary embodiment of a display device. The display device100comprises a gate driver110, a data driver120, and sub-pixels P11˜Pmn. The gate driver110provides scan signals SS1˜SSnto scan lines SL1˜SLn. In one embodiment, the gate driver110simultaneously outputs the scan signals SS1˜SSnand only asserts one of the scan signals SS1˜SSn. In other embodiments, the gate driver110utilizes a dynamic driving scheme (DDS) to provide the scan signals SS1˜SSnto the scan lines SL1˜SLn.

FIG. 2is a schematic diagram of an exemplary embodiment of the scan signals SS1˜SSn. In this embodiment, the gate driver110simultaneously outputs the scan signals SS1˜SSn. In the same period, only one scan signal is asserted and other scan signals are unasserted. For example, the scan signal SS1is in an asserted state and the scan signal SS2˜SSnare in an unasserted state in period T1. In period T2, the scan signal SS2is in an asserted state and the scan signal SS1, SS3˜SSnare in an unasserted state.

In this embodiment, the digital code of the asserted scan signal is 1001 and the digital code of the unasserted scan signal is 1100, but the disclosure is not limited thereto. In some embodiments, other digital codes can replace the digital codes (e.g. 1001 and 1100) to indicate the asserted scan signal and the unasserted scan signal.

Referring toFIG. 1, the data driver120provides data signal SD1˜SDmto the sub-pixels P11˜Pmnvia data lines DL1˜DLm. In this embodiment, each of the data signal SD1˜SDmand the asserted scan signal respond to a response signal. Thus, the amount of response signals is m. For example, when the scan signal SS1is asserted, the asserted scan signal SS1ane the data signal SD1˜SDmrespond with m response signals. Similarly, when the scan signal SS2is asserted, the asserted scan signal SS2and the data signal SD1˜SDmrespond with m response signals.

In this embodiment, the amount of pulses of the response signals relates to the color displayed by the corresponding sub-pixel. For example, the amount of pulses of the response signals received by the sub-pixels displaying the different colors may be different. Assuming the sub-pixel P11displays a red color, the sub-pixel P12displays a green color, and the sub-pixel P13displays a blue color, in one embodiment, the amount of pulses of the response signal received by the sub-pixel P11may be more than the amount of pulses of the response signal received by the sub-pixel P12and the amount of pulses of the response signal received by the sub-pixel P13. The amount of pulses of the response signal received by the sub-pixel P12may be more than the amount of pulses of the response signal received by the sub-pixel P13.

The sub-pixels display the corresponding colors according to the response signals. In this embodiment, the sub-pixels are arranged by an array. The amount of rows (horizontal direction) of the array is less than 500. In other words, the amount of scan lines is less than 500, but the disclosure is not limited thereto.

Additionally, the disclosure does not limit the method of forming the sub-pixels P11˜Pmn.FIG. 3Ais a schematic diagram of an exemplary embodiment of forming the sub-pixels P11˜Pmn. The sub-pixels P11˜Pmnare formed between the electrode layers (e.g. ITO)301and302. In this embodiment, the structure of the sub-pixels P11˜Pmnis a single-layered structure. Thus, the sub-pixels P11˜Pmndo not overlap with each other.

FIG. 3Bis a schematic diagram of another exemplary embodiment of forming the sub-pixels P11˜Pmn. The sub-pixel layer331is disposed between the electrode layers311and312, wherein the sub-pixels of the sub-pixel layer331display the red color. The sub-pixel layer332is disposed between the electrode layers313and314, wherein the sub-pixels of the sub-pixel layer332display the green color. The sub-pixel layer333is disposed between the electrode layers315and316, wherein the sub-pixels of the sub-pixel layer333display the blue color. Furthermore, an isolation layer321is disposed between the electrode layers312and313and an isolation layer322is disposed between the electrode layers314and315.

In the structure shown inFIG. 3B, the gate driver110can utilize the same or different scan lines to provide the scan signals to the pixel layers. For example, the gate driver110utilizes the different scan lines (e.g. SL1˜SL3) to provide the different scan signals (e.g. SS1˜SS3) to the pixel layers (e.g. layers331˜333shown inFIG. 3B). In one embodiment, the layers311,313, and315receive the scan signals SS1˜SS3respectively. In this case, the electrode layers312,314, and316receive data signals. In another embodiment, the electrode layers312,314, and316receive the scan signals SS1˜SS3and the layers311,313, and315receive data signals.

In other embodiments, the gate driver110can utilize a single scan line to provide scan signal to the pixel layers. In this case, although each pixel layers (e.g. layers331˜333shown inFIG. 3B) receive the same scan signal, the data signals provided to each pixel layers are used to control each pixel layers. For example, assuming the electrode layers311,313, and315receive a scan signal and the electrode layers312,314, and316receive the different data signals. When the data signals are controlled, each electrode layer can be respectively controlled. Additionally, in this embodiment, the sub-pixels coupled to the same scan line display the same color. For example, the sub-pixels P11, P21, P31, . . . , Pm1coupled to the scan line SL1display the red color. The sub-pixels P12, P22, P32, . . . , Pm2coupled to the scan line SL2display the green color. The sub-pixels P13, P23, P33, . . . , Pm3coupled to the scan line SL3display the blue color.

The disclosure does not limit the color displayed by the sub-pixel. In another embodiment, the sub-pixels coupled to the same data line display the same color. For example, the sub-pixels P11, P12, P13, . . . , P1ncoupled to the data line DL1display the red color. The sub-pixels P21, P22, P23, . . . , P2ncoupled to the data line DL2display the green color. The sub-pixels P31, P32, P33, . . . , P3ncoupled to the data line DL3display the blue color.

In this case, the scan signal SS1and the data signal SD1can respond with a first response signal. The scan signal SS1and the data signal SD2can respond with a second response signal. The scan signal SS1and the data signal SD3can respond with a third response signal. The sub-pixel P11can display the corresponding color (e.g. the red color) according to the first response signal. The sub-pixel P21can display the corresponding color (e.g. the green color) according to the second response signal. The sub-pixel P31can display the corresponding color (e.g. the blue color) according to the third response signal. In another embodiment, the sub-pixels P11, P21, and P31do not overlap with each other (as shown inFIG. 3A). In other embodiments, the sub-pixels P11, P21, and P31overlap with each other (as shown inFIG. 3B).

In one embodiment, each of the sub-pixels comprises Bi-stable material such as Cholesteric Liquid Crystal (ChLC). When each of the sub-pixels comprises the ChLC, each of the sub-pixels displays the corresponding color according to the voltage difference between the corresponding scan signal and the corresponding data signal. Thus, the response signal, which responded by the data signal and the scan signal, represents the voltage difference between the data signal and the scan signal.

FIG. 4Ais a schematic diagram of an exemplary embodiment of the response signals. The response signals shown inFIG. 4Acan be generated according to the corresponding scan signal and the corresponding data signal. Assuming the sub-pixel P11displays the red color, the sub-pixel P12displays the green color, and the sub-pixel P13displays the blue color, the symbol Sr11represents the response signal received by the sub-pixel P11, the symbol Sr12represents the response signal received by the sub-pixel P12, and the symbol Sr13represents the response signal received by the sub-pixel P13. In this embodiment, when the amount of pulses of the response signal is increased, the brightness of the corresponding sub-pixel is brighter.

As shown inFIG. 4A, the response signal Sr12comprises a selection stage and a non-selection stage and the response signal Sr13also comprises a selection stage and a non-selection stage. The selection stage of the response signal Sr12is longer than the selection stage of the response signal Sr13. The non-selection stage of the response signal Sr12is shorter than the non-selection stage of the response signal Sr13. In this embodiment, the amount of pulses of the non-selection stage of the response signal Sr12or Sr13is equal to zero. In addition, the response signal Sr11does not comprise a non-selection stage.

Before providing the response signal to the sub-pixels P11, P12, and P13, if the different preset voltages are provided to the sub-pixels P11, P12, and P13, reflectivity-voltage curves can be defined according to the reflectivity of the sub-pixels P11, P12, and P13.FIG. 4Bshows the reflectivity-voltage curves of the sub-pixels P11, P12, and P13. The curve400R is the reflectivity-voltage curve of the sub-pixel P11. The curve400G is the reflectivity-voltage curve of the sub-pixel P12. The curve400B is the reflectivity-voltage curve of the sub-pixel P13.

Since the curves400R,400G, and400B are not completely overlapping, the amount of pulses of the response signals Sr11˜Sr13are different (as shown inFIG. 4A). In another embodiment, if the amount of pulses of the response signals Sr11and Sr12are the same, the curves400R and400G are completely overlapping.

When the corresponding scan signal and the corresponding data signal are suitably adjusted according to the curves400R,400G, and400B, the appropriate response signals for the sub-pixels are generated. When the generated response signal are provided to the corresponding sub-pixels, new reflectivity-voltage curves of the sub-pixels will be generated and the new reflectivity-voltage curves are completely overlapping with each other. For example, if the curve400R is required to completely overlap the curve400G, the scan signal and the data signal received by the sub-pixel P11are adjusted to increase the amount of pulses of the response signal Sr11. If the curve400B is required to completely overlap the curve400G, the scan signal and the data signal received by the sub-pixel P13are adjusted to reduce the amount of pulses of the response signal Sr13.

Referring toFIG. 4B, if the voltage V1is provided to the sub-pixel P11, the reflectivity of the sub-pixel P11is R1. If the voltage V2is provided to the sub-pixel P13, the reflectivity of the sub-pixel P13is also equal to R1. In this embodiment, the voltage difference between the voltages V1and V2is less than 100V.

FIG. 5is a schematic diagram of an exemplary embodiment of a driving method of the disclosure. The driving method can be applied to a display device. The display device comprises a plurality of sub-pixels. In this embodiment, the sub-pixels are arranged in an array. The amount of rows of the array is less than 500, but the disclosure is not limited thereto.

First, a first scan signal and a second scan signal are provided (step S510). In one embodiment, a gate driver is utilized to provide a first scan signal and a second scan signal. In some embodiments, the gate driver utilizes the DDS to generate a first scan signal and a second scan signal.

When the first scan signal is asserted, a first data signal is provided (step S520). The first scan signal and the first data signal can respond with a first response signal. In this embodiment, the first response signal is the voltage difference between the first scan signal and the first data signal. Furthermore, the first response signal comprises a selection stage and a non-selection stage, wherein the pulse number in the non-selection stage is equal to zero. In other embodiments, the first response signal does not comprise the non-selection stage.

When the second scan signal is asserted, a second data signal is provided (step S530). The second scan signal and the second data signal can respond with a second response signal. The amount of pulses of the first response signal is different from the amount of pulses of the second response signal. In this embodiment, the second response signal is the voltage difference between the second scan signal and the second data signal. In one embodiment, the second response signal comprises a selection stage and a non-selection stage, wherein the pulse number in the non-selection stage is equal to zero. In other embodiments, the second response signal does not comprise the non-selection stage.

The first response signal is provided to a first sub-pixel among a plurality of sub-pixels (step S540). In this embodiment, the first sub-pixel displays a first color. Additionally, when the amount of pulses of the first response signal is increased, the brightness of the first sub-pixel is brighter. When the amount of pulses of the first response signal is reduced, the brightness of the first sub-pixel is darker.

The second response signal is provided to a second sub-pixel among the sub-pixels (step S550). In this embodiment, the second sub-pixel displays a second color. The second color is different from the first color. Additionally, when the amount of pulses of the second response signal is increased, the brightness of the second sub-pixel is brighter. When the amount of pulses of the second response signal is reduced, the brightness of the second sub-pixel is darker.

In this embodiment, the amount of pulses of the response signals relates to the color displayed by the sub-pixel. For example, when the first color is a red color and the second color is a green color, the amount of pulses of the first response signal is more than the amount of pulses of the second response signal. When the first color is a blue color and the second color is a green color, the amount of pulses of the first response signal is less than the amount of pulses of the second response signal.

The amount of pulses of the response signal can be determined according to the reflectivity-voltage curves of the sub-pixels. For example, when a sub-pixel receives a preset voltage, the reflectivity of the sub-pixel can be measured. The reflectivity-voltage curve of the sub-pixel can be obtained according to the measured reflectivity and the preset voltage.

Accordingly, if the first sub-pixel receives a first preset voltage and the second sub-pixel receives a second preset voltage, the reflectivity of the first and the second sub-pixels can be obtained after measuring the first and the second sub-pixels. The reflectivity of the first sub-pixel is referred to as a first reflectivity. The reflectivity of the second sub-pixel is referred to as a second reflectivity. In this embodiment, when the first reflectivity is the same as the second reflectivity, the voltage difference between the first and the second preset voltages is less than 100V.

FIG. 6is a schematic diagram of another exemplary embodiment of a driving method of the disclosure. When the gate driver110transmits the scan signal SS1to the different sub-pixels via the same scan line (e.g. SL1), the driving method described inFIG. 6can be employed. Furthermore, in this embodiment, the sub-pixels P11˜Pmndo not overlap with each other (as shown inFIG. 3A). In one embodiment, the sub-pixels P11˜Pmnare arranged in an array. The amount of rows of the array is less than 500, but the disclosure is not limited thereto. In some embodiments, a portion of the sub-pixels P11˜Pmnare overlapping with each other (as shown inFIG. 3B).

First, a scan signal is provided (step S610). The scan signal and a first data signal respond to a first response signal (step S620). The scan signal and a second data signal responds to a second response signal (step S630). TakingFIG. 1as an example, the scan signal SS1with the data signal SD1can respond to a response signal and the scan signal SS1with the data signal SD2can respond to another response signal.

The amount of pulses of the first response signal is different from the amount of pulses of the second response signal. Each of the first and the second response signals comprises a selection stage and a non-selection stage. In one embodiment, the amount of pulses of the non-selection stage is equal to zero (e.g. Sr11shown inFIG. 4A).

In this embodiment, the first response signal is the voltage difference between the scan signal and the first data signal. Similarly, the second response signal is the voltage difference between the scan signal and the second data signal.

The first response signal is provided to a first sub-pixel (step S640). The second response signal is provided to a second sub-pixel (step S650). The first sub-pixel displays a first color according to the first response signal. The second sub-pixel displays a second color according to the second response signal. In this embodiment, the first color is different from the second color.

In one embodiment, the amount of pulses of the response signals relates to the brightness of the sub-pixel. For example, when the amount of pulses of the first response signal is increased, the brightness of the first sub-pixel is brighter. Contrarily, when the amount of pulses of the first response signal is reduced, the brightness of the first sub-pixel is darker.

In another embodiment, the amount of pulses of the response signals relates to the color displayed by the sub-pixel. For example, when the first sub-pixel displays a red color and the second sub-pixel displays a green color, the amount of pulses of the first response signal is more than the amount of pulses of the second response signal. In some embodiments, when the first sub-pixel displays a blue color and the second sub-pixel displays a green color, the amount of pulses of the first response signal is less than the amount of pulses of the second response signal.

In this embodiment, the pulse shape of the scan signal or the data signal is controlled according to the reflectivity-voltage curves of the sub-pixels. Thus, the amount of pulses of the response signal can be defined for color balance. The method for defining the reflectivity-voltage curves is described inFIG. 4B, thus description is omitted here for brevity.