1. Field of the Invention
The present invention relates to an electrophoretic display module, and more particularly, to an electrophoretic display module capable of reducing power consumption.
2. Description of the Prior Art
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According to the above arrangement, the display unit D1-Dn can refresh display images according to the display voltages Vd1-Vdn. However, in the prior art, when the electrophoretic display module 100 refreshes a frame, the power converter 130 is continuously turned on, so as to increase power consumption of the electrophoretic display module 100. Therefore, the electrophoretic display module 100 of the prior art has bad power management efficiency.
The present invention provides an electrophoretic display module comprising an electrophoretic display panel, a driving circuit, and a power converter. The electrophoretic display panel comprises a plurality of display units. Each of the display units is configured to display images according to a display voltage. The driving circuit is electrically connected to the plurality of display units for outputting the display voltage to the corresponding display unit according to a first driving voltage and a second driving voltage, and changing the display voltage according to a display signal. The power converter is configured to output the first driving voltage and the second driving voltage to the driving circuit according to a power source during a frame refreshing period, wherein the power converter is turned off after a predetermined length of time following the driving circuit changing the display voltage.
The present invention further provides a control method of an electrophoretic display module. The control method comprises providing an electrophoretic display panel having a plurality of display units, each of the display units being configured to display images according to a display voltage; a power converter outputting a first driving voltage and a second driving voltage to a driving circuit during a frame refreshing period; the driving circuit outputting the display voltage to the corresponding display unit according to the first driving voltage and the second driving voltage; the driving circuit changing the display voltage according to a display signal; and during the frame refreshing period, turning off the power converter after a predetermined length of time following the driving circuit changing the display voltage.
In contrast to the prior art, the electrophoretic display module of the present invention is capable of turning off the power converter according to a time point when the display voltage is changed during the frame refreshing period, such that power consumption of the electrophoretic display module can be reduced. Therefore, the electrophoretic display module of the present invention has better power management efficiency.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
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When the display signal Sk of the display unit Dk is changed from the state 01b to the state 00b at time t2, the driving circuit 220 pulls down the display voltage Vdk corresponding to the display unit Dk from +V to 0 according to the display signal Sk. Similarly, the control circuit 240 continuously turns on the power converter 230 for the recovery time Trec after time t2, so as to recover the first driving voltage V1 and the second driving voltage V2 to the original voltage levels. And after the recovery time Trec, the control circuit 240 turns off the power converter 230. In addition, the control circuit 240 also interlacedly turns off and turns on the power converter 230 for keeping the display voltages Vd1-Vd1 within the proper range.
When the display signal Sk of the display unit Dk is changed from the state 00b to a state 10b at time t3, the driving circuit 220 further pulls down the display voltage Vdk corresponding to the display unit Dk from 0 to −V according to the display signal Sk. Similarly, the control circuit 240 continuously turns on the power converter 230 for the recovery time Trec after time t3, so as to recover the first driving voltage V1 and the second driving voltage V2 to the original voltage levels. And after the recovery time Trec, the control circuit 240 turns off the power converter 230. In addition, the control circuit 240 also interlacedly turns off and turns on the power converter 230 for keeping the display voltages Vd1-Vd1 within the proper range.
When the display signal Sk of the display unit Dk is changed from the state 10b to the state 00b at time t4, the driving circuit 220 pulls up the display voltage Vdk corresponding to the display unit Dk from −V to 0 according to the display signal Sk. Similarly, the control circuit 240 continuously turns on the power converter 230 for the recovery time Trec after time t4, so as to recover the first driving voltage V1 and the second driving voltage V2 to the original voltage levels. And after the recovery time Trec, the control circuit 240 turns off the power converter 230. In addition, the control circuit 240 also interlacedly turns off and turns on the power converter 230 for keeping the display voltages Vd1-Vd1 within the proper range.
Finally, when the electrophoretic display module 200 finishes refreshing the frame at time t5, the control circuit 240 pulls down the enable signal Ve to the low voltage level, for turning off the power converter 230.
According to the above arrangement, during the frame refreshing period, the power converter 230 is not continuously turned on, but is turned off after a recovery time Trec following changing of the display voltages Vd1-Vdn. Therefore, the power consumption of the electrophoretic display module 200 can be reduced.
On the other hand, if a time interval between the two adjacent time points when the display voltages are changed is not very long, changes of the display voltages may not affect the images displayed by the display units, thus the control circuit 240 can continuously turnoff the power converter 230 after the recovery time Trec following changing of the display voltages Vd1-Vdn instead of interlacedly turning off and turning on the power converter 230.
In addition, the power converter 230 can be a DC-to-DC power converter. During the frame refreshing period, the control circuit 240 can turn on the power converter 230 when the driving circuit 220 changes the display voltages, or the control circuit 240 can turn on the power converter 230 before the driving circuit 220 changes the display voltages.
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Step 510: Provide an electrophoretic display panel, wherein the electrophoretic display panel comprises a plurality of display units, and each of the display units is configured to display images according to a display voltage;
Step 520: A power converter outputs a first driving voltage and a second driving voltage to a driving circuit during a frame refreshing period;
Step 530: The driving circuit outputs the display voltage to the corresponding display unit according to the first driving voltage and the second driving voltage;
Step 540: The driving circuit changes the display voltage according to a display signal; and
Step 550: During the frame refreshing period, turn off the power converter after a predetermined length of time following the driving circuit changing the display voltage.
In contrast to the prior art, the electrophoretic display module of the present invention is capable of turning off the power converter according to a time point when the display voltage is changed during the frame refreshing period, such that power consumption of the electrophoretic display module can be reduced. Therefore, the electrophoretic display module of the present invention has better power management efficiency.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
Number | Date | Country | Kind |
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101145688 | Dec 2012 | TW | national |