Abstract:
Systems for displaying images are provided. The system includes a display device. The display device includes an array substrate, and a transparent electrode stack overlaying the array substrate. The transparent electrode stack includes a first electrode having a first slit, a second electrode having an outer edge disposed corresponding to the interior of the first slit, and a dielectric layer disposed between the first and second electrodes. The dielectric layer electrically isolates the first and second electrodes.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application claims priority of Taiwan Patent Application No. 098110078, filed on Mar. 27, 2009, the entirety of which is incorporated by reference herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to flat panel display technologies, and more specifically to display devices utilizing transverse electric field technologies. 
         [0004]    2. Description of the Related Art 
         [0005]    In general, a display device utilizing transverse electric field technology driving liquid crystal molecules in a plane approximately parallel to the substrate surface is suggested for improving a narrow viewing angle problem of a widely used TN (twisted nematic) display device. 
         [0006]    Transverse electric field technology can be categorized into the following technologies: IPS (In Plane Switching) technology and FFS (Fringe Field Switch) technology. IPS technology arranges comb-shaped pixel electrodes and comb-shaped common electrodes in a display. FFS technology forms an insulating layer, which is sandwiched between a top electrode layer and a bottom electrode layer on a same substrate in a display. For FFS technology, one of the electrode layers is utilized as a common electrode layer, and the other is utilized as a pixel electrode layer. Slits, for example, are formed in the top electrode layer and utilized as openings where an electrode field passes therethrough. 
         [0007]    However, display devices utilizing transverse electric field technology have variable and poor optical transmittance. 
         [0008]    Thus, a system for displaying images is required to solve the described problems. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    An embodiment of the invention provides a system for displaying images. The system includes a display device. The display device includes an array substrate, and a transparent electrode stack overlaying the array substrate. The transparent electrode stack includes a first electrode having a first slit, a second electrode having an outer edge disposed corresponding to the interior of the first slit, and a dielectric layer disposed between the first and second electrodes. The dielectric layer electrically isolates the first and second electrodes. 
         [0010]    Further scope of the applicability of the invention will become apparent from the detailed descriptions given hereinafter. It should be understood however, that the detailed descriptions and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, as various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the Art from the detailed descriptions. 
         [0011]    A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
           [0013]      FIGS. 1A and 1B  show an exemplary cross-section and a top view of a pixel area of a display device of a first embodiment of the invention; 
           [0014]      FIGS. 2A and 2B  show an exemplary cross-section and a top view of a pixel area of a display device of a second embodiment of the invention; 
           [0015]      FIGS. 3A and 3B  show an exemplary cross-section and a top view of a pixel area of a display device of a third embodiment of the invention; 
           [0016]      FIGS. 4A through 4C  show graphs of transmittances in the pixel areas of display devices of the first through third embodiments of the invention; 
           [0017]      FIG. 5  shows an exemplary top view of a pixel area of a display device of a fourth embodiment of the invention; 
           [0018]      FIG. 6  shows an exemplary top view of a transparent electrode stack of a display device of a fifth embodiment of the invention; and 
           [0019]      FIG. 7  schematically shows a system for displaying images of a preferred embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    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. 
         [0021]    Note that the concepts and specific practice modes of the invention is described in detail by the embodiments and the attached drawings. In the drawings or description, similar elements are indicated by similar reference numerals and/or letters. Further, the element shape or thickness in the drawings can be expanded for simplification or convenience of indication. Moreover, elements which are not shown or described can be in every form known by those skilled in the art. 
         [0022]    It is understood that the following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. 
         [0023]    In the subsequent description, phrases such as “substantially parallel (to each other)”, “substantially the same” and etc. . . . mean expected to be parallel (to each other), the same and etc. in design, as in practice, it is difficult to be mathematically or geometrically parallel (to each other), the same and etc. Additionally, when deviation is in an acceptable range of a corresponding standard or specification, it is also recognized to be parallel (to each other), the same and etc. Those skilled in the art are expected to acknowledge, that different standards or specifications, depend upon various properties and conditions, and thus, cannot be specifically listed. 
         [0024]    Specific embodiments of the invention for fabrication of a pixel area and a transparent electrode stack of a display device of a system for displaying images are described. It is noted that the concepts of the invention can be applied to any known or newly developed display device and system for displaying images. 
         [0025]    Referring to  FIGS. 1A and 1B , a pixel area  1  of a display device  400  of a first embodiment of the invention is shown.  FIG. 1A  is a cross-section plotted along the cross-section line I-I in  FIG. 1B . The display device  400  comprises an array substrate  100 . A layer of scan lines  10  and a layer of data lines  30  are disposed overlying the array substrate  100 . A dielectric layer (not shown) is disposed between the layer of the scan line  10  and the layer of the data lines  30 . The pixel areas (including the pixel area  1 ) of the display device  400  are defined by the vertical intersection of the scan lines  10  and the data lines  30 . A part of a scan line  30  serves as a gate electrode of a thin film transistor. A semiconductor layer  20  is disposed overlying the gate electrode, and a source electrode  30 S and a drain electrode  30 D are disposed overlying the semiconductor layer  20 . Thus forming a thin film transistor. Further, the drain electrode  30 D is electrically connected to the corresponding data line  30  by a branch line  31 . 
         [0026]    A transparent electrode stack is disposed overlying the array substrate  100 , and a dielectric layer  132  is disposed between the transparent electrode stack and the layer of the data lines  30 . The transparent electrode stack comprises a transparent first electrode  110 , a transparent second electrode  120 , and a dielectric layer  131  disposed between and isolating the electrodes  110  and  120 . Further, the first electrode  110  electrically connects to the source electrode  30 S and acts as a pixel electrode. The first electrode  110  comprises a plurality of slits. In this embodiment, the first electrode  110  comprises one connection electrode  115  and five sub-electrodes  116 . The five sub-electrodes  116  are connected to each other by the connection electrode  115  and spaced from each other by four open slits  111 ,  112 ,  113 , and  114 . In other embodiments, the quantity and type (open or enclosure) of the slits, and the quantity and type of the sub-electrodes and the connection electrode of the first electrode  110  may depend on requirements. The second electrode  120  is disposed below the first electrode  110 , and coupled to a common voltage source of the display device  400 , serving as a common electrode. The second electrode  120  has neither openings nor slits, which means the second electrode  120  is formed as an integral whole. Further, the first electrode  110  and the second electrode  120  respectively partially overlap with the data lines  30 . 
         [0027]    The display device  400 , such as a display panel, further comprises an opposite substrate  200 , a liquid crystal layer  300 , and a light shielding layer  210 . The opposite substrate  200  and the array substrate  100  are oppositely disposed and spaced from each other. The liquid crystal layer  300  is filled and disposed between the array substrate  100  and the opposite substrate  200 . The light shielding layer  210  is disposed overlying the opposite substrate  200 , which is between the substrates  100  and  200 . The light shielding layer  210  approximately overlaps the data lines  30  (the extension of the light shielding layer  210  approximately follows that of the data lines  30 ), and comprises at least one opening  211  exposing the pixel area  1  and parts of the transparent electrode stack not overlapping the data lines  30 . Further, at least one slit of the first electrode  110  is disposed corresponding to the opening  211 . 
         [0028]    The transmittance in the pixel area  1  of the display device  400  shown in  FIG. 1A  is shown in  FIG. 4A . The area  55  in  FIG. 4A  corresponds to the area in  FIG. 1A  affected by the light shielding effects of the light shielding layer  210 . The x-axis scales of  FIG. 4A  correspond to the left-to-right width position of the pixel area  1 . The y-axis scales of  FIG. 4A  indicate the transmittance values. The curve  51  in  FIG. 4A  indicates the transmittances of every position of the pixel area  1  shown in  FIG. 1A .  FIG. 4A  shows the average transmittance (Avg T) of the pixel area  1  is 72.83%. 
         [0029]    Referring to  FIGS. 2A and 2B , a pixel area  2  of a display device  400  of a second embodiment of the invention is shown.  FIG. 2A  is a cross-section plotted along the cross-section line II-II in  FIG. 2B . In some cases, a second electrode  140  in the pixel  2  can replace the second electrode  120  in the pixel  1  shown in  FIGS. 1A and 1B . 
         [0030]    Only the outer edge of the second electrode  140  of the pixel area  2  of the second embodiment is different from the pixel area  1  of the first embodiment. In  FIGS. 2A and 2B , an outer edge  140   a  of a second electrode  140  is disposed corresponding to the interior of the slit  111  of the first electrode  110 , and disposed beyond the two edges of the slit  111  (which means the outer edge  140   a  fails to overlap the two edges of the slit  111 ). The two edges of the slit  111  are substantially parallel to the extension direction of the data lines  30 . The outer edge  140   a  may be disposed along the middle of the slit  111  (that is, the outer edge  140   a  is disposed corresponding to a center line of the slit  111 ). Further, an outer edge  140   b  of the second electrode  140  may also be disposed corresponding to the interior of the slit  114  of the first electrode  110 . The outer edge  140   b  may be disposed along the middle of the slit  114 . That is, the outer edges  140   a  and  140   b  of the second electrode  140  of the second embodiment are respectively disposed corresponding to the interior of the slits  111  and  114  of the first electrode  110 . In other embodiments, one of the outer edges  140   a  and  140   b  of the second electrode  140  may extend over the neighboring data line  30  as the corresponding edge of the second electrode  120  as shown in  FIG. 1B . In this embodiment, further, the outer edges  140   a  and  140   b  of the second electrode  140  are both substantially parallel to the extension direction of the data lines  30 . 
         [0031]    The transmittance in the pixel area  2  of the display device  400  shown in  FIG. 2A  is shown in  FIG. 4B  where a curve  52  indicates the transmittances of every position of the pixel area  2 . Compared to the curve  51  shown in  FIG. 4A , values of troughs, whose orthographic projections on an x-axis are near the positions corresponding to those of the outer edges  140   a  and  140   b  of the second electrode  140  in  FIG. 2A , of the curve  52  (such as those indicated by dotted circles in  FIG. 4B ), increase relative to the values of troughs at the corresponding positions of the curve  51 . Thus, the transmittance variance in the pixel area  2  decreases, and the average transmittance of the pixel area  2  increases. For example,  FIG. 4B  shows the average transmittance of the pixel area  2  at 75.83%, greater than 72.83% of the pixel area  1 . 
         [0032]    Referring to  FIGS. 3A and 3B , a pixel area  3  of a display device  400  of a third embodiment of the invention is shown.  FIG. 3A  is a cross-section plotted along the cross-section line III-III in  FIG. 3B . In some cases, a second electrode  150  in the pixel  3  can replace the second electrode  120  in the pixel  1  shown in  FIGS. 1A and 1B  or the second electrode  140  in the pixel  2  shown in  FIGS. 2A and 2B . The pixel area  3  of the third embodiment is different from the pixel area  2  of the second embodiment in that the second electrode  150  in the pixel area  3  comprises a plurality of slits. In this embodiment, the second electrode  150  comprises one connection electrode  155  and three sub-electrodes  156 . The three sub-pixels  156  are connected to each other by the connection electrode  155 , and spaced from each other by the two open slits  151  and  152 . In other embodiments, the quantity and type (open or enclosure) of the slits, and the quantity and type of the sub-electrodes and the connection electrode of the second electrode  150  may depend on requirements. Further, compared to the second electrode  140  shown in  FIGS. 2A and 2B , the increased “edges” due to formation of slits between the sub-electrodes  156  of the second electrode  150  are considered the outer edges of the second electrode  150 . 
         [0033]    As shown in  FIG. 3B , the slits  151  and  152  of the second electrode  150  are respectively disposed corresponding to the slits  112  and  113  of the first electrode  110 . The outer edges  151   b  and  152   b  of the second electrode  150  respectively along the length directions of the slits  151  and  152  are respectively disposed corresponding to the interior of the slits  112  and  113 . The outer edges  151   b  and  152   b  may be respectively disposed along the center lines of the slits  112  and  113 . In this embodiment, the widths of the slits  151  and  152  are substantially the same as those of the slits  111  through  114 . In other embodiments, the widths of the slits  151  and  152  can be greater than those of the slits  111  through  114 . In some cases, for example, the slits  151  and  152  can be between 1 and 2 times as wide as the slits  111  through  114 . In some cases, the slits  151  and  152  can be numerically wider than the slits  111  through  114 . In one embodiment, for example, the slits  111  through  114  are as wide as 3 μm, while the slits  151  and  152  are wider than 3 μm. 
         [0034]    In this embodiment, further, only one outer edge  150   a  of all of the edges of the second electrode  150  orthographically projects on the interior of the slit  111  of the first electrode  110 , for example. Moreover, only one outer edge  151   b  of one slit  151  orthographically projects on the interior of the slit  112  of the first electrode  110 , for example. 
         [0035]    The transmittance in the pixel area  3  of the display device  400  shown in  FIG. 3A  is shown in  FIG. 4C  where a curve  53  indicates the transmittances of every position of the pixel area  3 . Compared to the curves  51  and  52  shown in  FIGS. 4A and 4B , values of troughs, whose orthographic projections on an x-axis are near the positions corresponding to those of the outer edges  150   a ,  151   b ,  152   b , and  150   b  of the second electrode  150  in  FIG. 3A , of the curve  53  (such as those indicated by dotted circles in  FIG. 4C ) are apparently increased relative to the values of troughs at the corresponding positions of the curves  51  and  52 . Thus, the transmittance variance in the pixel area  3  decreases, and the average transmittance of the pixel area  3  increases. For example,  FIG. 4C  shows the average transmittance of the pixel area  3  at 77.07%, greater than those of the pixel areas  1  and  2 . 
         [0036]    In the device of the fourth embodiment shown in  FIG. 5 , compared to the device of the third embodiment, the size of the first electrode  110  is reduced, and no longer overlaps the data lines  30 . A pair of outer edges  151   a  and  151   b , along the length direction of the slit  151 , of the second electrode  150  are respectively disposed corresponding to the interior of the two slits  111  and  112  of the first electrode  110 . A pair of outer edges  152   a  and  152   b , along the length direction of the slit  152 , of the second electrode  150  are respectively disposed corresponding to the interior of the two slits  114  and  113  of the first electrode  110 . The respective corresponding mode between the outer edges of the second electrode  150  and the slits of the first electrode  110  is the same as or equivalent to that between the outer edge  140   a  of the second electrode  140  and the slits of the first electrode  110  described for and shown in  FIG. 2A . In this embodiment, further, the outer edge  150   a  (or  150   b ) is disposed corresponding to one sub-electrode  116  of the first electrode  110 . In other words, the outer edge  150   a  (or  150   b ) orthographically projects on one sub-electrode  116 . 
         [0037]    In the fifth embodiment of the invention, the first electrode  110  shown in  FIG. 3B  or  5  is replaced by a transparent electrode  810  comprising enclosure slits  811 ,  812 ,  813 , and  814  shown in  FIG. 6 , and the second electrode  150  shown in  FIG. 3B  or  5  is replaced by a transparent electrode  820  comprising enclosure slits  821  and  822  shown in  FIG. 6 . The corresponding mode of relative positions between the transparent electrodes  810  and  820  is the same as or equivalent to that of relative positions between the electrodes  110  and  150  shown in  FIG. 3B  or  5 . The slits  811  and  812  are substantially parallel to each other, and the slits  813  and  814  are substantially parallel to each other, but the slits  812  and  813  are not parallel. A pixel area comprising the transparent electrodes  810  and  820  is called “dual domain”. A pixel area comprising the transparent electrode  820  and modified transparent electrode  810  comprising substantially parallel slits  811 ,  812 ,  813 , and  814  is called “mono domain”. Further, the profile of the transparent electrode  820  may be modified to have two tapered outer edges respectively disposed corresponding to the interior of the slits  811  and  814 , and substantially parallel to directions of the slits  811  and  814 . 
         [0038]    As shown in  FIG. 7 , the display device  400  can be assembled with an input unit  500  to fabricate different kinds of the electronic device  600 . The display device may comprise only one type of the described pixel areas  1 ,  2 ,  3 , and  4 , or any combination of the described pixel areas  1 ,  2 ,  3 , and  4 . The input unit  500  is coupled to the display device  400 , inputting signals, such as image signals, into the display device  400  for image generation and display. The electronic device  600  can be a cell phone, a digital camera, a personal digital assistant (PDA), a notebook computer, a desktop computer, a television, a car display, or a portable digital video disc (DVD) player. 
         [0039]    While the invention has been described by way of example and in terms of preferred 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.