Abstract:
A system for displaying images is disclosed. A display panel having a multi-domain pixel structure comprises a plurality of electrodes that are physically separated form one another, each defining a domain within pixel, and a capacitance element, electrically connecting the electrodes.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a display device, and more particularly to a liquid crystal display device. 
         [0003]    2. Description of the Related Art 
         [0004]    Liquid crystal displays (LCD) have become widely used, with a working principle based on alignment condition of liquid crystal molecules changing by application of an electrical field so as to change the path of light passing therethrough. Typically, an LCD includes two opposite substrates with a gap therebetween receiving liquid crystal. Both substrates are formed with electrodes to control orientation and arrangement of liquid crystals. Images are displayed on the LCD panel by controlling orientation of liquid crystals with electrical field, in which bright dots or dark dots are generated where the light passes or is blocked. 
         [0005]    LCDs, however, present several disadvantages and limitations, among narrow view angle. At present, a number of propositions for manufacturing wide view angle LCD are in the developing stage. The most widely adopted technique is the so-called multi-domain vertical alignment (MVA) technology. The alternately positioned slit-spacing-protrusion structure in each pixel is used and a single pixel is divided into several domains so that liquid crystal molecules in different domains have different tilt directions. Hence, view angle of the LCD is increased. 
         [0006]      FIG. 1A  shows a plan view of pixel structure of a conventional multi-domain vertical alignment liquid crystal display.  FIG. 1B  is a cross section along line I-I′ of  FIG. 1A . Referring to  FIG. 1A  and  FIG. 1B , a pixel  102  comprises a plurality of domains, such as a first domain  104 , and a second domain  106  and a third domain  108 , wherein the pixel  102  has a pixel electrode that comprises a plurality of domain electrodes. A thin film transistor  110  and a storage capacitor Cst  134  are arranged in the first domain  104 . In the first domain  104 , a polysilicon layer  114  is formed on a array substrate  100 . A gate insulating layer  116  is formed on a portion of the polysilicon layer  114  (In order to simplify the diagram, the gate insulating layer  116  is not shown in  FIG. 1   a ). A first gate line  118  and a second gate line  120  pass on the gate insulating layer  116 . A first channel  151  is disposed underlying the first gate line  118  and in the polysilicon layer  114 . A first source  153  and a first drain  155  are disposed on opposite sides of the first channel  151 . A second channel  157  is disposed underlying the second gate line  120  and in the polysilicon layer  114 . A second source  159  and a second drain  161  are disposed on opposite sides of the second channel  157 . 
         [0007]    The gate lines  118  and  120  and the polysilicon layer  114  are covered by an interlayer dielectric layer  122 . A data line  124  and a drain electrode  128  of are formed on the interlayer dielectric layer  122 , in which the data line  124  and the drain electrode  128  electrically connect the polysilicon layer  114 . The data line  124  and the drain electrode  128  are covered by a planarization layer  130 . A domain electrodes  132  (a part of the pixel electrode) is formed on the planarization layer  130 , in which the domain electrodes  132  electrically connects the drain electrode  128  of the thin film transistor  110 . The storage capacitor Cst  134  comprises the polysilicon layer  114 , the gate insulating layer  116  and a first metal layer  119 . 
         [0008]    In a transflective liquid crystal display, a reflective layer  112  is formed on the domain electrode  132 , substantially overlapping the storage capacitor Cst  134 . In conventional technology, the domains  104 ,  106  and  108  are connected by a thin ITO neck  140  therebetween. The ITO neck  140  cannot be too wide to avoid affecting performance of the liquid crystal display. The reflective layer  112 , however, is likely to react with the domain electrode  132  thereunder, such that the reacted ITO neck  140  is easily cracked to generate dots, and the domains cannot have the same voltage level. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    A system for displaying images is disclosed. The system for displaying images comprising a display panel having a multi-domain pixel structure comprises a plurality of electrodes that are physically separated form one another, each defining a domain within pixel, and a capacitance element, electrically connecting the electrodes. 
         [0010]    A system for displaying images is also provided. The system for displaying images comprising a multi-domain pixel structure of a display panel further comprises a thin film transistor electrically connecting a pixel electrode of the display panel, wherein the pixel electrode comprises a plurality of domain electrodes domain separated with each other. A conductive line (layer) electrically connects all the domain electrodes. 
         [0011]    Further, in other embodiments, the display panel further comprises a first substrate. A thin film transistor is disposed overlying the first substrate, electrically connecting a pixel electrode of the display panel, wherein the pixel electrode comprises a plurality of domain electrodes. The domain electrodes are separated with each other; and a storage capacitor Cst disposed overlying the first substrate, electrically connecting the domain electrodes of the pixel electrode. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
           [0013]      FIG. 1A  is a plan view of a pixel structure a conventional multi-domain vertical alignment liquid crystal display. 
           [0014]      FIG. 1B  is a cross section along line I-I′ of  FIG. 1A . 
           [0015]      FIG. 2A  is a plan view of a pixel of a multi-domain vertical alignment liquid crystal display, in accordance with an embodiment of the invention. 
           [0016]      FIGS. 2B and 2C  are cross sections along line II-II′ of  FIG. 2A . 
           [0017]      FIG. 3A  is a plan view of a pixel of a multi-domain vertical alignment liquid crystal display, in accordance with another embodiment of the invention. 
           [0018]      FIG. 3B  is cross sections along line III-III′ of  FIG. 3A . 
           [0019]      FIG. 3C  is cross sections along line IV-IV′ of  FIG. 3A . 
           [0020]      FIG. 4  schematically shows a embodiment of a system for displaying images, incorporating the multi-domain vertical alignment structure of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. Embodiments of the invention, which provides a liquid crystal display panel, will be described in greater detail by referring to the drawings that accompany the invention. It is noted that in the accompanying drawings, like and/or corresponding elements are referred to by like reference numerals. 
         [0022]    Exemplary embodiments of systems for displaying images will now be described. In this regard,  FIG. 2A  depicts an embodiment of such a system. Specifically, the system incorporates a liquid crystal display panel  200  of an embodiment of the invention.  FIG. 2B  is a cross section along line II-II′ of  FIG. 2A . Referring to  FIG. 2A  and  FIG. 2B , a pixel  202  comprises a plurality of domains separating with each other, such as a first domain  204 , and a second domain  206  and/or a third domain  208 . The pixel  202  has a pixel electrode  242  comprises a plurality of domain electrodes can be separated with each other by a slit area  270 . In the embodiment, the pixel electrode comprising three domain electrodes  244 ,  246 , and  248  is taken for an example. The invention, however, is not limited thereto. The pixel electrode can comprise more or less domain electrodes. 
         [0023]    A thin film transistor  210  is arranged in the first domain  204 . A semiconductor layer  212 , such as a polysilicon layer or an amorphous silicon layer, is formed on an array substrate  201  (or called first substrate). The array substrate  201  can be a low alkali glass substrate or a non alkali glass substrate. A gate insulating layer  214 , such as silicon oxide, silicon nitride or silicon oxynitride, is formed on a portion of the semiconductor layer  212 . Two gate lines  216  and  218 , such as Al, Mo or combinations thereof or stack layers thereof, pass on the gate insulating layer  214 . The gate lines  216  and  218 , and the semiconductor layer  212  are covered by an interlayer dielectric layer  220 , such as silicon oxide, silicon nitride or silicon oxynitride. A data line  222  for inputting data signals to the display panel  200  and a drain electrode  226  are formed on the interlayer dielectric layer  220 , electrically connecting the semiconductor layer  212 . The data line  222 , drain electrode  226  and the interlayer dielectric layer  220  are covered by a planarization layer  228 , such as an organic layer. The pixel electrode  242 , such as ITO, is formed on the planarization layer  228 , and electrically connects the drain electrode  226  of the thin film transistor  210 . In an embodiment of the invention, the display is a transflective display, and a reflective layer  232 , such as Al, is disposed on a portion of the pixel electrode  202 . 
         [0024]    A storage capacitor Cst  234  is disposed under the first domain electrode  244  and beyond the thin film transistor  210 . The storage capacitor Cst  234  comprises a conductive line (serving as a bottom electrode)  236  on the array substrate  201 , a capacitance dielectric layer  238  on the conductive line  236  and a top electrode  240  on the capacitance dielectric layer  238 . In some embodiments of the invention, the conductive line  236  of the Cst  234  and the semiconductor layer  212  of the thin film transistor  210  are the same layer, the capacitance dielectric layer  238  of the Cst  234  and the gate insulating layer  214  of the thin film transistor  210  are the same layer, and the top electrode  240  of the Cst  234  and the gate line  216  and  218  are the same layer. 
         [0025]    Still referring to  FIG. 2A  and  FIG. 2B , in some embodiments of the invention, a conductive line extends from the conductive line  236  of the storage capacitor Cst  234 , the same layer as the semiconductor layer  212 , to pass underlying the domain electrodes  244 ,  246  and  248  of the pixel electrode  242 , wherein the conductive line and the semiconductor layer  212  are the same layer, and the conductive line  236  can comprises polysilicon or amorphous silicon. 
         [0026]    The conductive line  236  covered by the interlayer dielectric layer  220  and the planarization layer  228  connects the first domain electrode  244 , the second domain electrode  246  and the third domain electrode  248  of the pixel electrode  242  electrode through vias  271 . 
         [0027]    in some embodiments of the invention, the liquid crystal display is a multi-domain vertical alignment (MVA) to obtain wider viewing angle. The liquid crystal display further comprises a color filter substrate  252  (or called second substrate) opposite the array substrate  201 , and a liquid crystal layer  254  is interposed between the array substrate  201  and the color filter substrate  252 . A plurality of protrusions  250  respectively responding to the domain electrodes  244 ,  246  and  248  are disposed on the inner side of the color filter substrate  252 . For example, a first protrusion  251  and a second protrusion  253  are disposed on the color filter substrate  252 , respectively corresponding to the second domain electrode  246  and the third domain electrode  248 . 
         [0028]    The via  271  for connecting the conductive line  212  and the domain electrodes  244 ,  246  and  248  can be overlapped with the protrusions  250  disposed on the color filter substrate  252  respectively to reduce affection of aperture ratio of the display device. 
         [0029]    According to an embodiment of the invention, the domain electrodes  244 ,  246  and  248  of the pixel electrode  242  are separated with each other by a slit area  270 . The domain electrodes  244 ,  246  and  248  are connected by a conductive line extending from the conductive line  236  of the storage capacitor Cst  234 . Thus, the domain electrodes can have substantially a same voltage level, and the ITO neck is not required. Consequently, the ITO neck crack problem could be eliminated, and performance of front of screen of the display device could be optimized. Further, a portion of the conductive line extending from the conductive line  236  connecting the domain electrodes  244 ,  246  and  248  are overlapped with the protrusions to reduce affection of aperture ratio of the display device. 
         [0030]      FIG. 2C  depicts another embodiment of such a system. Referring to  FIG. 2C , the top electrode  240  of the Cst  234  is electrically connected to a connection layer  231  through a third via. The connection layer  231 , the same layer as the data line, can be acted as a conductive line extending underlying the domain electrodes  246  and  248  of the pixel electrode  242 . The conductive line (connection layer  231 ) covered by the interlayer dielectric layer  228  connects the first domain electrode  244 , the second domain electrode  246  and the third domain electrode  248  of the pixel electrode  242  through fourth via  232 . 
         [0031]    As the embodiment shown in  FIG. 2B , the domain electrodes directly connect to the conductive line and are electrically contacted together. In the other hand, the embodiment shown in  FIG. 2C  discloses that the domain electrodes can also indirectly connect to the conductive line and are electrically contacted together. 
         [0032]    Another exemplary embodiment of systems for displaying images is also described, wherein the conductive line located directly below the data line. In this regard,  FIG. 3A  depicts an embodiment of such a system. Specifically, the system incorporates a liquid crystal display panel  300  of an embodiment of the invention.  FIG. 3B  is a cross section along line III-III′ of  FIG. 3A . Referring to  FIG. 3A  and  FIG. 3B , a pixel  302  comprises a plurality of domains, such as a first domain  304 , and a second domain  306  and/or a third domain  308 . In some embodiment, the domains  304 ,  306  and  308  of a pixel  302  are separated with each other by the slit area  370 . In the embodiment, a pixel comprising three domains is taken for an example. The invention, however, is not limited thereto. A pixel can comprise more or less domains. 
         [0033]    A thin film transistor  310  is arranged in the first domain  304 . In the first domain  304 , a semiconductor layer  312 , such as a polysilicon layer or an amorphous silicon layer, is formed on a first substrate  301 . In some embodiment, the first substrate  301  can be a low alkali glass substrate or a non alkali glass substrate. A gate insulating layer  314 , such as silicon oxide, silicon nitride or silicon oxynitride, is formed on a portion of the semiconductor layer  312 . A first gate line  316  and a second gate line  318 , such as Al, Mo or combinations thereof or stack layers thereof, pass on the gate insulating layer  314 . A first channel  351  is disposed underlying the first gate line  316  and in the polysilicon layer  312 . A first source  353  and a first drain  355  are disposed on opposite sides of the first channel  351 . A second channel  357  is disposed underlying the second gate line  318  and in the polysilicon layer  312 . A second source  359  and a second drain  361  are disposed on opposite sides of the second channel  357 . 
         [0034]    The gate lines  316  and  318 , and the semiconductor layer  312  are covered by an interlayer dielectric layer  320 , such as silicon oxide, silicon nitride or silicon oxynitride. A data line  322  and a drain electrode  326  are formed on the interlayer dielectric layer  320 , in which the data line  322  and the drain electrode  326  electrically connect the semiconductor layer  312 . The data line  322  and the drain electrode  326  are covered by a planarization layer  328 , such as an organic layer (the planarization layer  328  is omitted in  FIG. 3A  to avoid obscuring the figure). A pixel electrode  342 , such as ITO, is formed on the planarization layer  328 , in which the pixel electrode  342  electrically connects the drain electrode  326  of the thin film transistor  310 . In an embodiment of the invention, the display is a transflective display, and a reflective layer  332 , such as Al, is disposed on a portion of the pixel electrode  342 . 
         [0035]    A storage capacitor Cst  334  is disposed nearby the thin film transistor  310 . In an embodiment of the invention, the storage capacitor Cst  334  occupies smaller area of the first domain than conventional technology. In some embodiment of the invention, the bottom electrode of the Cst  334  and the semiconductor layer  312  of the thin film transistor  310  are the same layer acting as a conductive line, the capacitance dielectric layer  338  of the Cst  334  and the gate insulating layer  314  of the thin film transistor  310  are the same layer, and the top electrode  340  of the Cst  334  and the gate lines  316  and  318  are the same layer. The bottom electrode (conductive line)  312  is electrically connected to the drain electrode  326  of the thin film transistor  310  through a via, and the drain electrode  326  is connected to the pixel electrode  342 . 
         [0036]    In addition, a second substrate  352 , such as color filter substrate is disposed opposite the first substrate  301 . A liquid crystal layer  354  is interposed between the first substrate  301  and the second substrate  352 . 
         [0037]      FIG. 3C  is a section view taken along line IV-IV′ of  FIG. 3A . Referring to  FIG. 3A , and  FIG. 3B , the pixel electrode  342  comprises a plurality of domain electrodes  344 ,  346  and  348 , physically separated by the slit  370  with each other. 
         [0038]    In an embodiment of the invention, the storage capacitor Cst  334  comprises two portions  335  and  337 , both extending in a different direction. In some embodiment, a first portion  337  of the storage capacitor Cst  334  is disposed in the first domain  304 , extending in a row direction. A second portion  335  of the storage capacitor Cst  334  extends in a column direction and underlying the data line for connecting the domain electrodes  344 ,  346  and  348  of the pixel electrode  342 . In some embodiment, the storage capacitor Cst  334  is L shape, wherein the first portion  237  and the second portion  335  of the storage capacitor Cst  334  are perpendicular with each other. 
         [0039]    As well, the domain electrodes  344 ,  346  and  348  of the pixel electrode  342  are connected by a portion  335  of the storage capacitor Cst  334  underlying the data line  322 . In addition, the storage capacitor Cst  334  connects the domain electrodes  344 ,  346  and  348  of the pixel electrode  342  through via in the interlayer dielectric layer  320  and/or the planarization layer  328 . Note that the storage capacitor Cst  334  is required to be isolated from the data line  322 . 
         [0040]    Referring to  FIG. 3A , in an embodiment of the invention, the system for displaying image incorporating a liquid crystal display is a multi-domain vertical alignment (MVA) to obtain wider viewing angle. A plurality of protrusions  350  respectively responding to the domains are disposed on the inner side of the color filter substrate  352 , wherein the protrusions  350  reduce affection of aperture ratio of the display panel. For example, a first protrusion  351  and a second protrusion  353  are disposed on the color filter substrate  352 , respectively corresponding to the second domain  306  and the third domain  308 . 
         [0041]    According to an embodiment of the invention, the domain electrodes  344 ,  346  and  348  of a pixel electrode  342  are separated in the slit area  370 , such that performance of front of screen of the display panel could be optimized. In addition, the domain electrodes  344 ,  346  and  348  are connected by the storage capacitor Cst  334  to have a same voltage level, and the ITO neck is not required. Consequently, the ITO neck crack problem could be eliminated. Further, since the storage capacitor Cst of an embodiment of the invention occupies smaller area of the domain electrode  344 , and a portion of the storage capacitor Cst  335  is overlapped with the data line  322 , the aperture ratio of the display could be increased. 
         [0042]      FIG. 4  schematically shows an embodiment of a system for displaying images which is implemented as a liquid crystal display device  400  comprising the display panel  200  (or  300 ) or an electronic device  600  incorporating Such the liquid crystal display device  400 . The electronic device  600  may include a portable handheld device such as a portable DVD player, a mobile phone, a digital camera, a personal digital assistant (PDA), a desktop computer, a television, an in-car display, or a laptop computer. As shown in  FIG. 4 , the liquid crystal display device  400  may comprise a liquid crystal display panel  200  shown in  FIG. 2A  or the liquid crystal display panel  300  shown in  FIG. 3A . In some embodiments, the display device  400  can be incorporated into the electronic device  600 . The electronic device  600  may comprise the display device  400  comprising the display panel  200  and a controller  500  coupled to the display panel  200 , in which the controller  500  is operative to control the display panel  200  to render images in accordance with input. 
         [0043]    While the invention has been described by way of example and in terms of embodiment, it is to be understood that the invention is not limited thereto. 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.