This present application claims priority to TAIWAN Patent Application Serial Number 099139433, filed on Nov. 16, 2010, which are herein incorporated by reference.
The present invention relates to a display driving system, and particularly to a driving system and a driving method for an electronic paper display system.
Nowadays, electronic papers are more and more popular. With respect to the traditional electronic paper (hereinafter called E-paper), as shown in
For one example, as shown in
Given that a frame has N gray levels, the waveform output unit 120 needs to store N×N output conditions in the look-up table (LUT), as shown in
Therefore, the prior art of an E-paper 10 not only needs larger memory to store at least two frame data, but requires larger storage space to store N×N output conditions in the look-up table (LUT) 122. Nevertheless, the driving system of the present invention needs to store no more than one frame data and to keep lesser output conditions (i.e., 2N), and consequently the memory capacity of the driving system of the present invention can be reduced tremendously.
The present invention discloses a driving system for display, and the system needs less memory capacity than the prior art. The driving system of the present invention includes: A frame data input unit for inputting a frame data, a storage device storing the frame data in sequence from the frame data input unit, a waveform generation unit receiving the frame date from the storage device, wherein the waveform generation unit further comprises a look-up table (LUT) selector and a LUT output unit. After receiving the frame data from the storage device, the waveform generation unit, via the LUT selector, informs the LUT output unit of outputting a control signal. The driving system further includes a display unit receiving the control signal from the LUT output unit and displaying a frame corresponding to the frame data on the display unit.
The storage device includes the storage device include DRAM, SRAM, Flash memory, and the other storage devices being capable of reading the frame data successively and/or randomly from the frame data input unit. One of the improvements of the present invention is that the capacity of the storage device can be reduced to a critical capacity less than the size of storing two frame data, even not more than the size of storing one frame in a good design.
The LUT output unit in the waveform generation unit further includes a displaying LUT output device and a clearing LUT output device, wherein the displaying LUT output device and the clearing LUT output device are electrically coupled to the display unit and output the control signal corresponding to the frame data to the display unit. The displaying LUT output device sends out the control signal to show a frame corresponding to the frame data on the display unit, and the clearing LUT output device sends out the control signal to clear a current frame on the display unit. In the condition that a frame with N gray levels, the displaying LUT output device only needs to store N displaying output conditions and the clearing LUT output device only needs to store N clearing output conditions.
In one embodiment, the display unit of the present invention includes a symmetric bi-stable display, which substantially has symmetric characteristic, so that the LUT output unit is replaced by a flip flop device and the LUT selector is simplified to be a LUT unit. Hence, the waveform generation unit includes a LUT unit and a flip flop device. The flip flop device can output a clearing control signal or a displaying control signal to clear or show the frame, respectively, on the symmetric bi-stable display. Besides, the displaying control signal and the clearing control signal are substantially symmetric and complementary. Both the displaying control signal and the clearing control signal include a DC voltage or a switching waveform with equivalent DC voltage. The duration of an active state of the DC voltage or the equivalent DC voltage is manipulated to control the gray levels of the display. In the condition that a frame with N gray levels, the LUT unit only needs to store N output conditions.
In one embodiment, a position DC voltage or a positive equivalent DC voltage (hereinafter called a first voltage) and a negative DC voltage or a negative equivalent DC voltage (hereinafter called a second voltage) are employed to control the gray levels. The longer duration of the first voltage is, the more darkness of the display unit shows, and the shorter duration of the first voltage is, the more brightness of the display unit shows. On the contrary, the longer duration of the second voltage is, the more brightness of the display unit shows, and the shorter duration of the first voltage is, the more darkness of the display unit shows. The relationship between the voltage vales and the darkness or brightness of the display depends on the characteristic of the display. In another embodiment, it can be that the longer duration of the first voltage is, the more brightness of the display unit shows, and whereas the longer duration of the second voltage is, the more darkness of the display unit shows
The present invention further discloses a method of driving a display. The method applied on the above-mentioned driving system includes: When the display unit would like to update a new frame, the waveform generation unit first reads the frame data of a current frame from the storage device. Thereupon the waveform generation unit, via the LUT selector, informs the LUT output unit of outputting the control signal to clear the current frame on the display unit. After reading a new frame data from the frame data input unit, the storage device sends the new frame data to the waveform generation unit. The LUT selector informs the LUT output unit of sending the control signal to update the new frame on the display unit.
In one embodiment, the method applied on the above-mentioned driving system includes: When the symmetric bi-stable display would like to update a new frame, the waveform generation unit first reads the frame data of a current frame from the storage device. Thereupon the LUT unit informs the flip flop device of outputting the control signal to clear the current frame on the symmetric bi-stable display. After reading a new frame data from the frame data input unit, the storage device sends the new frame data to the waveform generation unit. The LUT unit informs the flip flop device of sending the control signal to update the new frame on the symmetric bi-stable display.
The storage device in the embodiment can be reduced to a critical capacity less than the size of storing two frame data, even not more than the size of storing one frame in a well design. Furthermore, provide that a frame with N gray levels, the output conditions in the LUT unit is reduce to N instead of 2N.
The above objects, and other features and advantages of the present invention will become more apparent after reading the following detailed description when taken in conjunction with the drawings, in which:
a) illustrates the driving system of present invention only needs to store N clearing output conditions, if a frame has N gray levels.
b) illustrates the driving system of present invention only needs to store N displaying output conditions, if a frame has N gray levels.
a) illustrates the displaying control signals for a bi-stable display.
b) illustrates the clearing control signals for a bi-stable display.
The present invention will be described in detail by using the following embodiments and it will be recognized that those descriptions and examples of embodiments are used to illustrate but not to limit the claims of the present invention. Hence, other than the embodiments described in the following, the present invention may be applied to the other substantially equivalent embodiments.
The present invention discloses a driving system for display, and particularly for an electronic paper (E-paper), hereinafter called E-paper, system or the other display systems containing bi-stable display. As shown in
As shown in
In one embodiment, the LUT output unit 222 includes a displaying LUT output device 222_1 and a clearing LUT output device 222_2. The LUT output unit 222 issues displaying control signals from the displaying LUT output device 222_1 to the bi-stable display 230 for updating a new frame or issues clearing control signals from the clearing LUT output device 222_2 to the bi-stable display 230 for clearing a current frame.
In one embodiment, provided that the bi-stable display 230 is showing a current frame, wherein the data of the current frame is kept in the storage device 210 concurrently. Provided that the driving system 20 would like to update a new frame, before the storage device 210 reads the new frame data from the frame data input 200, the waveform generation unit 220 first reads the current frame data from the storage device 210 and the LUT selector 221 selects the clearing LUT output device 222_2 to send out clear signals to clear the current frame on the bi-stable display 230 after the right clearing output condition generated from the clearing LUT output device 222_2 is selected. After that the new frame data is read from the frame data input 200 into the storage device 210 and is sent to the waveform generation unit 220. In the meantime, the LUT selector 221 selects the displaying LUT output device 222_1 to send out display signals to update the new frame on the bi-stable display 230 after the right displaying output condition generated from the displaying LUT output device 222_1 is selected.
In one embodiment, given that the current frame has N gray levels, it will need to store N clearing output conditions (Cond.c(1)˜Cond.c(N)) in the clearing LUT output device 222_2, as exemplified in
The bi-stable display 230 used in the driving system 20 has two stable states and has the characteristics that if the longer duration of a first voltage is applied to the bi-stable display 230, the more darkness the bi-stable display 230 shows and, on the contrary, if the longer duration of a second voltage is applied, the more brightness the bi-stable display 230 shows. The first voltage and the second voltage are symmetrical voltage with respect to a reference voltage. For one example, provided that the reference voltage is 0V and the first voltage is 5V, the second voltage should be −5V.
In one embodiment, as shown in
The clearing LUT output device 222_2 generates clearing control signals 51, which act like the inverse signal of displaying control signals 41, to control gray levels of the bi-stable display 230. As shown in
The positive state 42 of displaying control signals 41 and the negative state 52 of and clearing control signals 51 are not limited to be DC voltages. In one embodiment, as shown in
In one embodiment, given that a bi-stable display owns substantially symmetric characteristic, called symmetric bi-stable display, the displaying LUT output device 222_1 and the clearing LUT output device 222_2 are substantially symmetrical and complementary. Therefore, the driving system of the present invention can be modified to the architecture as shown as in
In one embodiment, given that a displaying control signal with a duration of positive state 42, the clearing control signal would have the negative state 52 with the same duration as the positive state 42. In other words, clearing control signals are inverse signals of displaying control signals.
In one embodiment, as shown in
Although some embodiments of the present invention have been described, it will be understood by those skilled in the art that the present invention should not be limited to the described preferred embodiments. Rather, various changes and modifications can be made within the spirit and scope of the present invention, as defined by the following Claims.
Number | Date | Country | Kind |
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099139433 | Nov 2010 | TW | national |