Abstract:
The present invention discloses an electro-phoretic display. The electro-phoretic display includes an electro-phoretic panel, a touch sensing module, for sensing a touch position, a column driver, a row driver, for selecting a row to be driven; and a controller, for determining an updating position according to the touch position; wherein, the column driver provides a data signal according to the updating position and the row driver provides a selecting signal according to the updating position such that a pixel corresponding to the updating position is updated.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an electro-phoretic display, and more particularly, to an electro-phoretic touch display. 
         [0003]    2. Description of the Prior Art 
         [0004]    It has been suggested that electro-optical elements for converting an electrical action into an optical action be used as display devices of various types of electronic apparatuses, such as monitor, mobile phone or PDAs (Personal Digital Assistants). Electro-phoretic displays comprise a layer of electro-phoretic material, a term which is used herein in its conventional meaning in the imaging art to refer to a material having first and second display states differing in at least one optical property, the material being changed from its first to its second display state by application of an electric field to the material. 
         [0005]    To obtain a high resolution electro-phoretic display, a two-dimensional addressing scheme with a plurality of data lines and a plurality of select lines is a way to achieve that requirement. In this scheme, each pixel being defined by the intersection of one data line and one select line. A pixel is connected via a non-linear element (transistor or diode) to drive circuitry used to control the operation of the display. One row (it is here assumed that the select lines define the rows of the matrix and the data lines define the columns, but obviously this is arbitrary, and the assignments could be reversed if desired) of pixels is selected by applying a voltage to a specific select line, and the voltages on the data or column lines are adjusted to provide the desired optical response from the pixels in the selected row. The pixel electrodes in the selected row are thus raised to voltages which is close to but (for reasons explained below) not exactly equal to the voltages on their associated data lines. The next row of pixels is then selected by applying a voltage to the next select line, so that the entire display is written on a row-by-row basis. 
         [0006]    When the non-linear elements are transistors (typically thin film transistors (TFT&#39;s)), it is conventional practice to place the data and select lines, and the transistors, on one side of the electro-phoretic medium, and to place a single common electrode, which extends across numerous pixels, and typically the whole display, on the opposed side of the electro-phoretic medium. The common electrode is normally provided on the viewing surface of the display (i.e., the surface of the display which is seen by an observer). During writing of the display, the common electrode is held at a fixed voltage, known as the “common electrode voltage” or “common plane voltage” and usually abbreviated “V.sub.COM”. This common plane voltage may have any convenient value, since it is only the differences between the common plane voltage and the voltages applied to the various pixel electrodes which affects the optical states of the various pixels of the electro-phoretic medium. Most types of electro-phoretic media are sensitive to the polarity as well as the magnitude of the applied field, and thus is necessary to be able to drive the pixel electrodes at voltages both above and below the common plane voltage. For example, the common plane voltage could be 0, with the pixel electrodes varying from −V to +V, where V is any arbitrary maximum voltage. Alternatively, it is common practice to hold the common plane voltage at +V/2 and have the pixel electrodes vary from 0 to +V. 
         [0007]    One important application of electro-phoretic media is in portable electronic devices, where battery life is an important consideration, and thus it is desirable to reduce the power consumption of the display as far as possible. Liquid crystal displays are not bistable, and hence an image written on such a display must be constantly refreshed if the image is to remain visible. The power consumed during such constant refreshment of an image is a major drain on the battery. In contrast, an electro-phoretic display need only be written once, and thereafter the bistable medium will maintain the image for a substantial period without any refreshing, thus greatly reducing the power consumption of the display. 
         [0008]    As the application of touch panel being more popular, the electro-phoretic display is required to have this feature. Although the electro-phoretic display only need be written once, when applied the touch feature, the data on the electro-phoretic display will be changed frequently. The electro-phoretic display has to be refreshed frequently; otherwise the touch sensibility of the display will be lower. Therefore, the electro-phoretic display with touch panel feature will consume much more power than electro-phoretic display without the touch feature. 
       SUMMARY OF THE INVENTION 
       [0009]    It is therefore a primary objective of the claimed invention to provide an electro-phoretic touch display with touch panel function to lower power consumption when updating the touched pixel display data. 
         [0010]    The present invention discloses an electro-phoretic display comprising an electro-phoretic panel, a touch sensing module, for sensing a touch position, a column driver, a row driver, for selecting a row to be driven; and a controller, for determining an updating position according to the touch position; wherein, the column driver provides a data signal according to the updating position and the row driver provides a selecting signal according to the updating position such that a pixel corresponding to the updating position is updated. 
         [0011]    The present invention also discloses an electro-phoretic display comprising an electro-phoretic panel, a touch sensing module, for sensing a touch position; a column driver, for providing a data signal; a row driver, for selecting a row to be driven; a controller, for controlling the column driver and the row driver; and a voltage provider, for providing a predetermining voltage to a pixel corresponding to the touch position to update the pixel. 
         [0012]    The present invention further discloses a method of driving an electro-phoretic display comprising an electro-phoretic layer, a touch sensing module, a column driver and a row driver, the method comprising: utilizing the touch sensing module to sense a touch position; and updating a first pixel within a predetermined range of the touch position and ceasing providing power to a second pixel located outside the predetermined range. 
         [0013]    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. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a schematic diagram of an electro-phoretic display with the touch sensing controller and cascading data driver according to an embodiment of the present invention. 
           [0015]      FIG. 2  is a schematic diagram of an electro-phoretic display with the touch sensing function embedded into controller and cascading data driver according to an embodiment of the present invention. 
           [0016]      FIG. 3  is a schematic diagram of an electro-phoretic display with the touch sensing controller and point-to-point data driver according to an embodiment of the present invention. 
           [0017]      FIG. 4  is a schematic diagram of an electro-phoretic display with the touch sensing function embedded into controller and point-to-point data driver according to an embodiment of the present invention. 
           [0018]      FIG. 5  shows image pixels and touch sensing points according to an embodiment of the present invention. 
           [0019]      FIG. 6  shows a touch position on image pixels of an electro-phoretic display according an embodiment of the present invention. 
           [0020]      FIG. 7  shows a touch sensing module and an electro-phoretic layer according to an embodiment of the present invention. 
           [0021]      FIG. 8  shows a touch sensing module of  FIG. 7 . 
           [0022]      FIG. 9  shows a touch sensing module of  FIG. 7 . 
           [0023]      FIG. 10  shows a touch sensing module of  FIG. 7 . 
           [0024]      FIG. 11  shows a touch sensing module of  FIG. 7 . 
           [0025]      FIG. 12  is a schematic diagram of a plurality micro-electro-mechanical system switches utilizing on an electro-phoretic display. 
           [0026]      FIG. 13  is a schematic diagram of a plurality switches and a voltage provider utilizing on an electro-phoretic display. 
           [0027]      FIG. 14  is a flow chart of an updating touched position method according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Please refer to  FIG. 1  in conjunction with  FIG. 7 .  FIG. 1  shows an electro-phoretic display system  100  according to a first embodiment of the present invention. As shown in  FIG. 1 , the electro-phoretic display system has a panel  101 , a controller  102 , a data driver  103 , a selecting driver  105  and a touch sensing controller  111 .  FIG. 7  is a structure diagram according to the panel  101 , which has two components, a touch sensing module  701  and an electro-phoretic layer  702 . The electro-phoretic s layer has a plurality of pixels (e.g. P 1 , P 2 , P 3 , P 4  . . . ), each pixel has a TFT transistor connected to a data line  107  and a selecting line  109 . The selecting driver  105  turns on the TFT transistor and the data driver  103  sends an image data to the corresponding pixel. The touch sensing module  701  is used to sense a touch on the panel  101 , and provides a touch sensing signal to the touch sensing controller  111  through the touch sensing signal lines  113  and  115 . The touch sensing controller  111  receives the touch sensing signal and identifies a touch position according to the touch sensing signal, and then the touch sensing controller  111  sends the touch position to the controller  102  through a signal line  117 . 
         [0029]    The touch sensing module  701  in  FIG. 7  could be realized in many ways. Please refer to  FIG. 8  to  FIG. 11 , which depict different types of touch sensing modules. As shown in  FIG. 8 , a resistive touch sensing module  800  is presented. The resistive touch sensing module  800  comprises an ITO film  801 , an ITO glass  803 , a display device  805  and spacer  807 . The ITO film  801  is separated from the ITO glass  803  by a plurality of spacer  807 . There is a voltage difference between the ITO film  801  and the ITO glass  803 , when an object  809  touches the display, the place being touched will have a voltage change. Utilizing the voltage change, a touch position will be identified. Please refer to  FIG. 9 , which depicts a capacitive touch sensing module  900 . As shown in  FIG. 9 , the capacitive touch sensing module  900  comprises a SiO 2  layer  901 , an ITO layer  903 , a glass layer  905  and an ITO layer  907 . The SiO 2  layer  901  is used as a protection of the ITO layer  903 . When an object touches the display, an electrical field will be established on the ITO layer  903 . Utilizing the electrical field, a touch position will be identified. Please refer to  FIG. 10 , which depicts an acoustic touch sensing module. The acoustic touch sensing module  1000  comprises a first transmitter  1001 , a second transmitter  1003 , a first receiver  1005  and a second receiver  1007 . The first transmitter  1001  and the second transmitter  1003  will transmit acoustic waves to form a uniform acoustic field on the display. When an object touches the display, the first receiver  1005  and the second receiver  1007  will receive the variance of the acoustic field, so as to identify the touch position. Please refer to  FIG. 11 , which depicts an optical touch sensing module  1100 . The optical touch sensing module  1100  comprises a plurality of horizontal transmitters  1101 , a plurality of vertical transmitters  1103 , a plurality of horizontal receivers  1105  and a plurality of vertical receivers  1107 . The plurality of horizontal transmitters  1101  and the plurality of vertical transmitters  1103  emit lights (e.g. infrared lights) to form a light matrix on the display. When an object touch the panel, the plurality of horizontal receivers  1105  and the plurality of vertical receivers  1107  will sense that touch (e.g. the emitted lights may be blocked), and identify the touch position. These touch sensing modules are examples of touch sensing modules, and should not limit the scope of this invention. 
         [0030]    Please refer to  FIG. 1  again. In this embodiment, the controller  102  can be a timing controller for sending data signals to the data driver  103  and sending timing control signals to the data driver  103  and the selecting driver  105 . The data driver  103  is electrically coupled to the controller  102  through a plurality of data signal lines  118 , and the selecting driver  105  is electrically coupled to the controller  102  through a plurality of selecting signal data lines  119 . Please note, the data driver  103  shown in  FIG. 1  could be a plurality of data drivers  103  for large display panel, or could be only one data driver  103  for small display panel. The selecting driver  105  could be plurality of drivers or only one driver as described above. When the display image is changed, the controller  102  sends the updating data and timing control signals to the data driver  103  and the selecting driver  105  for updating the new image on the panel  101 . The selecting driver  105  turns on the selecting line  109  one by one (in some cases, the selecting line  109  can be turned on two by two or three by three), and the data driver  103  sends image data to the corresponding data line  107 . A user can read a new frame of data by using above process. 
         [0031]    The controller  102  can also receive the touch position outputted by the touch sensing controller  111 . In many cases, a resolution of image display (total display pixel counts) is higher than a resolution of a touch panel (total touch sensing point counts). As shown in  FIG. 5 , the solid grids are image pixels and the dotted grids are touch sensing points. In some of the pixels and points, there is misalignment existed. Of course, in some case, the resolution of image display can be equal or higher than the resolution of the touch panel, and that is also within the scope of this invention. In this case, the controller  102  identifies a nearby pixel according to the touch position. The nearby pixel is therefore corresponding to an updating position. The controller  102  then outputs an updated data according to the updating position. Please note, in this embodiment, when nearby pixel corresponding to the updating position is being updated, only one selecting line  109  corresponding to the nearby pixel is turned on, and only one data line  107  corresponding to the nearby pixel sends the image data to the nearby pixel. Unlike the traditional driving method, a whole frame of pixels needs to be driven when new image data needs to be displayed. According to this invention, only one pixel corresponding to the updating position needs to be driven, so the power consumption will be lower. The touch sensing controller  111  can process the touch position and identify the nearby pixel, then output the updating position according to the position of the nearby pixel to the controller  102 . The controller  102  receives the updating position and only needs to update the nearby pixel according the updating position. In a case that the image pixels have the same position to the touch points, the touch position is equal to the updating position. 
         [0032]      FIG. 2  shows an electro-phoretic display system  200  according to a second embodiment of the present invention. The difference between the first embodiment and the second embodiment is the touch sensing controller  111  of the first embodiment embedded into the controller  202  of the second embodiment. When the display image is changed, the controller  202  sends the updating data and timing control signals to a data driver  203  and sends timing control signals to a selecting driver  205  for updating the new image on a panel  201 . The selecting driver  205  turns on a selecting line  209  one by one (in some cases, the selecting line  209  can be turned on two by two or three by three), and the data driver  203  sends image data to the corresponding data line  207 . When the panel  201  is touched, the controller  202  senses a touch sensing signal to determine a touch position. And then the controller  202  determines an updating position (corresponding to a pixel located at the touch position or an above-mentioned nearby pixel). The following steps are similar to the first embodiment, and will not narrate here again. 
         [0033]      FIG. 3  and  FIG. 4  show third and fourth embodiments of the present invention. The third embodiment is corresponding to the first embodiment, and the fourth embodiment is corresponding to the second embodiment. The only difference between the third embodiment and the first embodiment is that in the first embodiment, the controller  102  is connected to the first data driver  103  (the leftist one), and the second data driver (the one on the right side of the leftist one) is connected to the first data driver  103 . The controller  102  sends the data signals to the first data driver  103 , and the first data driver  103  passes the data signals to the second data driver  103 . But in the third embodiment, the controller  302  is connected to the first data driver  303  (the leftist one) and the second data driver  303  (the one on the right side of the leftist one) directly. The controller  302  directly sends the data signals to the first data driver  303  and the second data driver  303 . The difference between the fourth embodiment and the second embodiment is similar to the difference between the third embodiment and the first embodiment, and will not narrate here again. 
         [0034]    When an object touches the panel, the object may touch on the center of a pixel or between two or more pixels as shown in  FIG. 6 . In  FIG. 6 , the star sign is a touch position. When the touch position is on the center of pixel P m,n , the controller  102  ( 202 ,  302 ,  402 ) updates the value of the pixel P m,n . So other pixels which are not touched are not necessary to be updated in order to lower the power consumption. When the touch position is on two or more pixels, as shown in  FIG. 6 , the touch position is on the pixels P m−1,k  and P m,k , the controller  102  ( 202 ,  302 ,  402 ) updates both of the pixels P m−1,k  and P m,k . Please note, the above-mentioned updating mechanism is only regarded as an embodiment, not a limitation of the present invention. Actually, the controller  102  ( 202 ,  302 ,  402 ) can be designed according to different demands. For example, a designer can also utilize the controller  102  ( 202 ,  302 ,  402 ) to update the pixel P m,k  since the area being touched on P m,k  is larger than on P m−1,k , or randomly update one of these two pixels. In some cases, when an object touches the panel, the data of the touched pixel and pixels nearby the touched pixel will be affected because of the touch. The controller  102  ( 202 ,  302 ,  402 ) can be designed to update a predetermined range of pixels nearby the touch pixel.—For example, when the pixel P m,n  is being touched, the nine pixels from P m−1,n−1  P m+1,n+1  will be updated. These changes all obey the spirit of the present invention. 
         [0035]    Another method to update the touched pixel is utilizing a micro-electro-mechanical system switch. As shown in  FIG. 12 , an electro-phoretic display  1200  comprises a plurality of pixels  1201 , a plurality of pixel electrodes  1202 - 1 ˜ 1202 - 3 , a plurality of micro-electro-mechanical system switches  1203 - 1 ˜ 1203 - 3  and a voltage provider  1204 . When an object  1205  touches the display, a pressure under the object  1205  causes the micro-electro-mechanical system switch  1203 - 2  connecting to the pixel electrode  1202 - 2 , so the voltage provider  1204  can provide voltage to the pixel to update the touched pixel value. The micro-electro-mechanical system switch can be combined with a touch sensing module if the touch position is required, or without the touch sensing module if the touch position is not required. The touch sensing module can refer to  FIG. 8  to  FIG. 11  and corresponding description are similar as above. The electro-phoretic display  1200  with micro-electro-mechanical system switch can be used in the first to fourth embodiments corresponding to  FIG. 1  to  FIG. 4  respectively. The details of the first to fourth embodiments are the same, and will not be narrated here again. 
         [0036]      FIG. 13  is another embodiment to update a pixel being touched. As shown in  FIG. 13 , an electro-phoretic display  1300  comprises a data driver  1303 , a selecting driver  1305 , a controller  1302 , a plurality of data lines  1307 , a plurality of selecting lines  1309 , a voltage provider  1304  and a plurality of switches  1310 . When the display is touched, a switch control signal  1311  connects the corresponding data line  1307  to the voltage provider  1304  and the controller  1302  turns on the corresponding selecting line  1309  by the selecting driver  1305 . So the pixel being touched can be updated by the voltage provider  1304 . The switch control signal  1311  is generated according to a touch position, and the touch position is generated by a touch sensing module. The touch sensing module can refer to  FIG. 8  to  FIG. 11  and corresponding description are similar as above. The electro-phoretic display  1300  with switches can be used in the first to fourth embodiments corresponding to  FIG. 1  to  FIG. 4  respectively. The details of the first to fourth embodiments are the same, and will not be narrated here again. 
         [0037]      FIG. 14  shows a flowchart of updating a pixel being touched on an electro-phoretic display according to the present invention. As shown in step  1410 , the electro-phoretic display senses a touch position. After the electro-phoretic display receives the touch position, the display determines a nearby pixel position corresponding to the touch position as shown in step  1420 . It should be noted that in some case the nearby pixel position is equal to the touch position, and the step  1420  may be omitted therefore. The electro-phoretic display then determines pixels need to be updated (corresponding to the updating position) according to the nearby pixel position and a predetermined range as shown in step  1430 . It should be noted that the predetermined range could be several pixels around the nearby pixel, or the predetermined range could be only one pixel which is the nearby pixel itself. The electro-phoretic display then updates the pixels need to be updated but does not update at least one pixel outside the predetermined range as shown in step  1440 . It should be noted that at least one pixel outside the predetermined range is not updated (for example, the power is not supplied to the pixel) for lowering the power consumption. In an embodiment, the pixels outside the predetermined range are not updated. This can reduce more power consumption. But, in another embodiment, part of the pixels outside the predetermined range can be updated according to special need, e.g. clock information display area needs to be updated. 
         [0038]    To sum up, the present invention provides the novel electro-phoretic display with touch panel functions, which can reduce more power consumption. 
         [0039]    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.