Abstract:
An E-ink display and method for repairing the same is provided. The method is for repairing a thin film transistor array substrate of the E-ink display. The thin film transistor array substrate having a plurality of pixel units is provided initially. Each of the pixel unit includes a thin film transistor and a pixel electrode. The thin film transistor has a gate electrode, a source electrode and a drain electrode. The gate electrode, the source electrode and the drain electrode are connected electrically to a scan line, a data line and the pixel electrode respectively. A portion of the pixel electrode is located above the scan line. Next, a repairing portion is formed at the space between the scan line and the pixel electrode. The repairing portion is utilized to electrically connect the pixel electrode and the scan line.

Description:
RELATED APPLICATIONS 
     The present application is based on, and claims priority from, Taiwan Application Serial Number 95110154, filed Mar. 23, 2006, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field of Invention 
     The present invention relates to a display and a method for repairing the same, and more particularly, to an E-ink display and a method for repairing the same. 
     2. Description of Related Art 
     In recent years, there has been an increasing demand for a thin display device with low power consumption. An example of such display device is an electronic-ink (E-ink) display with a display layer formed by electrically charged, electrophoretically mobile particles capable of translating through a dispersion fluid (dielectric fluid) upon application of an electric field to the medium. Varying the dispersion state of electrophoretic particles by an electric field changes the optical characteristics of the display layer, so the E-ink display can display a desired image. Moreover, the E-ink display can be a reflection-type and bistable display device that is expected to be lower power consumption. 
     A thin film transistor array substrate including a plurality of pixel units can be utilized to drive an E-ink display. Each of the pixel units has a thin film transistor serving as a switching element for each pixel unit. However, a defective thin film transistor may lead the pixel unit to be a white spot or a dark spot. 
     The white spot or the dark spot may damage the quality of the E-ink display seriously. Accordingly, how to provide an E-ink display and a method for repairing the same, which can repair a defective pixel unit manifested as a white spot or a dark spot on the screen is an issue of great consequence to improve the quality of the E-ink display. 
     SUMMARY 
     The present invention provides an E-ink display and a method for repairing the same, which can repair a defective pixel unit manifested as a white spot or a dark spot on the screen, in order to improve the quality of the E-ink display. 
     It is another aspect of the present invention to provide an E-ink display and a method for repairing the same, which can prevent structural damage in the repairing process, so that the yield of the E-ink display can be improved. 
     Accordingly, the present invention provides a method for repairing a thin film transistor array substrate of an E-ink display. The thin film transistor array substrate has a plurality of pixel units. Each of the pixel units is connected with a scan line and a data line. At least one of the pixel units is defective. The method includes the following steps. The thin film transistor array substrate is initially provided. Each of the pixel unit includes a thin film transistor and a pixel electrode. The thin film transistor has a gate electrode, a source electrode and a drain electrode. The gate electrode, the source electrode and the drain electrode are connected electrically to the scan line, the data line and the pixel electrode respectively. A portion of the pixel electrode is located above the scan line. A repairing portion is formed at the space between the scan line and the pixel electrode. The repairing portion is utilized to electrically connect the pixel electrode and the scan line. 
     The present invention also provides a method for repairing a thin film transistor array substrate of an E-ink display. The thin film transistor array substrate has a plurality of pixel units. Each of the pixel units is connected with a scan line and a data line. At least one of the pixel units is defective. The method includes the following steps. The thin film transistor array substrate is provided initially. Each of the pixel unit includes a thin film transistor and a pixel electrode. The thin film transistor has a gate electrode, a source electrode and a drain electrode. The gate electrode, the source electrode and the drain electrode are connected electrically to the scan line, the data line and the pixel electrode respectively. The scan line has a protruding portion. A portion of the pixel electrode is located above the protruding portion. A repairing portion is formed at the space between the protruding portion and the pixel electrode. The repairing portion is utilized to electrically connect the pixel electrode and the scan line. 
     The present invention also provides an E-ink display including a first substrate, a second substrate and an E-ink layer. The first substrate has a plurality of pixel units. Each of the pixel units is connected with a scan line and a data line. At least one of the pixel units is repaired. The second substrate is opposed to the first substrate. The second substrate has a transparent electrode layer. The E-ink layer is sandwiched between the first substrate and the second substrate. The E-ink layer has a plurality of charged particles and liquid. The optical characteristics of the pixel unit are varied by the dispersion state of charged particles in the liquid. Each of the pixel unit includes a thin film transistor and a pixel electrode. The thin film transistor has a gate electrode, a source electrode and a drain electrode. The gate electrode, the source electrode and the drain electrode are connected electrically to the scan line, the data line and the pixel electrode respectively. A portion of the pixel electrode is located above the scan line. A repairing portion is formed at the space between the scan line and the pixel electrode. The repairing portion is utilized to electrically connect the pixel electrode and the scan line. 
     According to preferred embodiments, a defective pixel unit can be repaired by connecting a pixel electrode and a scan line of the pixel unit electrically, thus improving the quality of the E-ink display. Moreover, since a repairing portion can be formed at the space between the scan line and the pixel electrode, a defective pixel unit can be repaired without any added structure. Further, repairing the pixel unit above a protruding portion of a scan line can prevent the scan line from being damaged during the laser welding process, thus increasing the yield of the E-ink display. 
     It is to be understood that both the foregoing general description and the following detailed description are by examples and are intended to provide further explanations of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects and advantages of the invention will become apparent by reference to the following description and accompanying drawings, which are given by way of illustration only, and thus are not limitative of the invention, wherein: 
         FIG. 1  illustrates a pixel unit of a thin film transistor array substrate according to the preferred embodiment of the present invention; 
         FIG. 2  illustrates a partial, cross-sectional view of an E-ink display according to the preferred embodiment of the present invention; 
         FIG. 3  illustrates a repaired pixel unit according to the preferred embodiment in  FIG. 1  of this invention; 
         FIG. 3A  illustrates a cross-sectional view from the A-A′ line in  FIG. 3 ; and 
         FIG. 4  illustrates a pixel unit of a thin film transistor array substrate according to another preferred embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  illustrates a pixel unit of a thin film transistor array substrate according to the preferred embodiment of the present invention. With reference to  FIG. 1 , a pixel unit  200  disposed on a first substrate  100  of a reflection-type E-ink display includes a thin film transistor  300  and a pixel electrode  210 . The pixel unit  200  is connected with a scan line  314  and a data line  326 . The thin film transistor  300  has a gate electrode  312  connected electrically to the scan line  314 , a source electrode  322  connected electrically to the data line  326  and a drain electrode  324  connected electrically to the pixel electrode  210  via a contact window  302 . It is worth noting that a portion of the pixel electrode is located above the data line  326 , the scan line  314  and the thin film transistor  300 . 
       FIG. 2  illustrates a partial, cross-sectional view of an E-ink display according to the preferred embodiment of the present invention. Referring to  FIG. 1  and  FIG. 2 , the E-ink display  800  includes a first substrate  100 , a second substrate  500  opposed to the first substrate  100  and an E-ink layer  600  sandwiched between the first substrate  100  and the second substrate  500 . The E-ink layer  600  includes a plurality of charged particles  614  and liquid  612 . The optical characteristics of the display layer  600  are varied by the dispersion state of charged particles  614  in the liquid  612 . In accordance with an embodiment of the present invention disclosed herein, the charged particles  614  include a plurality of positively charged particles  616  and a plurality of negatively charged particles  618 . The positively charged particles  616  have a different color to the negatively charged particles  618 . For example, the positively charged particles  616  are black and the negatively charged particles  618  are white, or vice versa. 
     The pixel unit  200  presents the color of the positively charged particles  616  when the positively charged particles  616  are affected to move up (direction of users) and the negatively charged particles  618  are affected to move down by an electric field, or vice versa. It should be noted that the present invention is not intended to be limited to the embodiment. In a preferred embodiment, the charged particles  614  and the liquid  612  can be contained in a plurality of microcapsules or a plurality of microcups. In another preferred embodiment, the charged particles  614  and the liquid  612  can be dispensed freely in an active region of the E-ink layer  600  without any lateral structural constrain. 
     With continued reference to  FIG. 1  and  FIG. 2 , the first substrate  100  and the second substrate  500  may be made of glass or flexible material. The second substrate  500  has a transparent electrode  510  made of indium tin oxide (ITO). The first substrate  100  has a first conductive layer  310 , a first dielectric layer  316 , a channel layer  330 , a second conductive layer  320  and a pixel electrode  210  disposed thereon. The first conductive layer  310  including a scan line  314  as well as a gate electrode  312  may be made of AlNd. The gate electrode  312  connects electrically with the scan line  314 . The first dielectric layer  316  disposed on the first substrate  100  and covering the first conductive layer  310  may be made of SiNx. The channel layer  330  disposed on the gate electrode  312  as well as the first dielectric layer  316  may be made of amorphous silicon or polysilicon. 
     The second conductive layer  320  may be made of materials selected from the group consisting of Aluminum, Titanium, Tungsten, Molybdenum and combinations thereof. The second conductive layer  320  includes the data line  326 , the source electrode  322  and the drain electrode  324 . The second dielectric layer  340  disposed on the first dielectric layer  316  and covering the second conductive layer  320  may be made of SiNx. The pixel electrode  210  disposed on the second dielectric layer  340  may be made of ITO. When a driving voltage is provided to the pixel electrode  210 , the charged particles  614  are affected by the electric field between the transparent electrode  510  and the pixel electrode  210 . The charged particles  614  move toward the transparent electrode  510  or the pixel electrode  210 , thus changing optical characteristics of the pixel unit  200 . It should be noted that the thin film transistor  300  can be a top-gate-type thin film transistor or a bottom-gate-type thin film transistor. 
       FIG. 3  illustrates a repaired pixel unit according to the preferred embodiment in  FIG. 1  of this invention. Referring to the  FIG. 3 , the pixel unit  200  has a repairing portion  710  formed by a laser welding method that adjusts the focus of a laser beam to weld the pixel electrode  210  and the scan line  314  together. The repairing portion  710  connects the pixel electrode  210  and the scan line  314  electrically. More specifically, the repairing portion  710  can be formed at the space between the scan line  314  and the pixel electrode  210 .  FIG. 3A  illustrates a cross-sectional view from the A-A′ line in  FIG. 3 . Referring to the  FIG. 3A , after the repairing process, the repairing portion  710  is formed between the scan line  314  and the pixel electrode  210 . 
     The electric field applied to the pixel unit  200  cannot be changed and the pixel unit  200  displays the intensity of the previous state unchangeably when the thin film transistor  300  is defective. For example, the pixel unit  200  displays as a white spot when the intensity of the previous state is high. In a preferred embodiment, the pixel unit  200  displays as a dark spot after the pixel unit  200  has been repaired. More specifically, the pixel electrode  210  and the scan line  314  have the same voltage level, a low voltage level in most of time, since the repairing portion  710  connects the pixel electrode  210  and the scan line  314  electrically. In a preferred embodiment, to the pixel unit  200 , a low intensity such as black color can be chosen to correspond to the low voltage level. The pixel unit  200  displays black color in most of time, so that the pixel unit  200  shows as a stationary dark spot. In general, the displayed color of pixel unit  200  is changed from white to dark after the pixel unit  200  has been repaired can decrease the contrast between the pixel unit  200  and the adjacent pixel thereof. Thus, the display quality of the pixel unit  200  can be improved. It should be noted that the present invention is not intended to be limited to repair a white spot. Similarly, connecting the pixel electrode  210  and the scan line  314  electrically can also repair the pixel unit  200 , so the displayed color of the pixel unit  200  is changed from dark to white in some special cases. It can be obtained by choosing an E-ink with reverse charged particles or a reverse driving voltage applied on the scan line  314 . 
       FIG. 4  illustrates a pixel unit of a thin film transistor array substrate according to another preferred embodiment of the present invention. Referring to the  FIG. 4 , a pixel unit  900  disposed on a first substrate  100  includes a thin film transistor  300  and a pixel electrode  210 . The pixel unit  900  is connected with a scan line  314  and a data line  327 . The thin film transistor  300  has a gate electrode  312  connected electrically to the scan line  314 , a source electrode  322  connected electrically to the data line  326  and a drain electrode  324  connected electrically to the pixel electrode  210  via a contact window  302 . The scan line  314  has a protruding portion  328 . A portion of the pixel electrode  210  is located above the scan line  314  and the protruding portion  328 . A repairing portion  720  can be formed at the space between the protruding portion  328  and the pixel electrode  210  when the pixel unit  900  is defective. For example, adjusting the focus of a laser beam to weld the pixel electrode  210  and the scan line  314  together, thereby connecting the pixel electrode  210  and the scan line  314  electrically. It is worth noting that locating the repairing portion  720  at the space between the protruding portion  328  and the pixel electrode  210  can prevent the scan line  314  from being damaged during the laser welding process. Thus, the yield of the E-ink display can be improved. 
     According to preferred embodiments mentioned above, the E-ink display and the method for repairing the same have the following advantages. Firstly, a defective pixel unit can be repaired by connecting a pixel electrode and a scan line of the pixel unit electrically, thus improving the quality of the E-ink display. Secondly, since a repairing portion can be at the space between the scan line and the pixel electrode, a defective pixel unit can be repaired without any added structure. Thirdly, repairing the pixel unit by utilizing a protruding portion of a scan line can prevent the scan line from being damaged during the laser welding process, thus increasing the yield of the E-ink display. 
     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.