Patent Publication Number: US-2009225064-A1

Title: Non-volatile display apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 097107896 filed in Taiwan, Republic of China on Mar. 6, 2008, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to a non-volatile display apparatus. 
     2. Related Art 
     As the demands for effectively handling and preserving a large number of data increase, the data are mostly processed by computers and the images are presented by the flat panel display apparatuses. However, since the size and weight of the conventional flat panel display apparatus are not more advantageous compared to the paper prints that are easy to read and carry, an electrophoretic display apparatus (EPD), using an electrophoretic material, is produced with the advantages of paper prints and benefits of electronic products such as data processing and environmental protection. 
     A conventional electrophoretic display apparatus  1  is illustrated in  FIGS. 1 and 2 .  FIG. 1  is a cross-sectional view along a line A-A in  FIG. 2  and  FIG. 2  is a schematic top view of the electrophoretic display apparatus  1 . 
     With reference to  FIGS. 1 and 2 , the electrophoretic display apparatus  1  includes a driving substrate  11  and an electrophoretic display material  12 . The driving substrate  11  is a TFT (thin film transistor) substrate having a plurality of pixel electrodes  111  and a lower substrate  112 . An electrophoretic display material  12  is disposed on a side of the driving substrate  11  and includes a plurality of electric particles C 1  and a dielectric solution L 1 . The electrophoretic material  12  is contained in a plurality of micro-cups  13 . Moreover, the electrophoretic display apparatus  1  further includes an upper substrate  14 , a common electrode layer  15  and an adhesive layer  16 . The electrophoretic display material  12  is sealed between the common electrode layer  15  and the driving substrate  11  and driven by the electric field formed by the common electrode layer  15  and the pixel electrode  111 . 
     Because the signal of the common electrode layer  15  comes from a control chip  114  or a control circuit connected to the driving substrate  11 , a connecting pad  113  is disposed on the driving substrate  11  while assembling, so as to electrically connect the common electrode layer  15  with the connecting pad  113  by a conductive gel S, such that a common voltage signal is transmitted to the common electrode layer  15  from the driving substrate  11 . 
     The pixel electrodes  111  form a rectangular area and correspond to a display surface D 1  (e.g. the large dotted-line rectangle as shown in  FIG. 2 ), i.e. an effective display area. In order to electrically connect the common electrode layer  15  and the driving substrate  11  in  FIG. 1 , the connecting pad  113  is disposed outside the display surface D 1  of the driving substrate  11 . The connecting pad  113  is disposed on the lower substrate  112  and the electrophoretic display material  12  corresponding to the connecting pad  113  has to be removed. After that, the common electrode layer  112  and the connecting pad  113  are electrically connected via the conductive gel S. The part where the connecting pad  113  is disposed cannot present the effective pixels to the user since there is no pixel electrode  111  and electrophoretic display material  12 ; hence it is a non-effective area N 1 . In conventional art, the non-effective display area N 1  exists in the part that the upper substrate  14  corresponds to the connecting pad  113 . Thus, in the top view, the shape of the upper substrate  14  is a rectangle with a protruding part B, which means, the upper substrate  14  is a concavo polygon (i.e. the polygon with an inner angle larger than 180 degrees). 
     The above-described electrophoretic display material  12 , micro-cups  13 , upper substrate  14  and common electrode layer  15  together may be referred to as an electrophoretic display film  10 . In general, the electrophoretic display film  10  is manufactured by upstream manufacturers, and the driving substrate  11  and the electrophoretic display film  10  are then assembled by downstream manufacturers or system manufacturers. The product can be applied in various display apparatuses, for example, an electronic book, an advertising panel, or a price tag. 
     As shown in  FIG. 3 , as the assembly manufacturer processes the cutting step to the large-area electrophoretic display films  10 ′, each of electrophoretic display films  10  is a concavo polygon rather than rectangle, therefore numerous waste parts W are left. This reduces cutting utility and increases the material cost. Moreover, as the size of the electrophoretic display apparatus  1  (e.g. the cell phone or PDA) becomes smaller, the ratio of the waste parts is higher. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, the present invention is to provide a non-volatile display apparatus that can enhance the cutting utility. 
     To achieve the above, a non-volatile display apparatus according to the present invention includes a driving substrate and a non-volatile display material. The driving substrate has a connecting pad and a plurality of pixel electrodes, which are distributed in X columns and Y rows. The non-volatile display material is disposed on a side of the driving substrate. Herein, the X columns and Y rows form a rectangular area and at least a part of the connecting pad is disposed in the rectangular area. 
     As mentioned above, a non-volatile display apparatus according to the present invention is to dispose the connecting pad in the pixel electrodes-distributed rectangular area formed by the X columns and Y rows, such that a protruding part does not have to be reserved when cutting the non-volatile display film and the waste parts will not be produced, so as to greatly enhance the cutting utility and cutting speed, hence reduce the material cost. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will become more fully understood from the detailed description and accompanying drawings, which are given for illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1  is a cross-sectional view of a conventional electrophoretic display apparatus; 
         FIG. 2  is a top view of the electrophoretic display apparatus in  FIG. 1 ; 
         FIG. 3  is a schematic view of a conventional large-area electrophoretic display film cut into a plurality of electrophoretic display films; 
         FIG. 4  is a cross-sectional view of a non-volatile display apparatus according to a first embodiment of the present invention; 
         FIG. 5  is a top view of the non-volatile display apparatus according to the first embodiment of the present invention; 
         FIG. 6  is a schematic view of a large-area non-volatile display film cut into a plurality of non-volatile display films in  FIG. 5 ; 
         FIG. 7  is a top view of a non-volatile display apparatus having a frame according to the first embodiment of the present invention; 
         FIGS. 8A to 8C  are schematic views of connecting pads in various aspects of a non-volatile display apparatus according to a second embodiment of the present invention; and 
         FIG. 8D  is a schematic view of the non-volatile display apparatus in yet another various aspect according to the second embodiment of the present invention, wherein the frame covers a non-effective display area. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements. 
     To further understand the technical features of the present invention, the technical terms of the present invention will be defined as follows. 
     A non-volatile display apparatus is a display apparatus with bi-stable states or multi-stable states. The non-volatile display apparatus may still maintain in one of the stable states for at least several hundreds milliseconds without power supply so to save a great amount of power. The non-volatile display apparatus has a non-volatile display material, for example, an electrophoretic material, an electromagnetic phoretic material, a liquid powder, a charged particle, an electro-chromatic material, an electrolysis material, twist balls (or rotating balls), or a cholesteric liquid crystal. 
     The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements. 
       FIG. 4  is a cross-sectional view of a non-volatile display apparatus according to a first embodiment of the present invention. As shown in  FIG. 4 , the non-volatile display apparatus  2  includes a driving substrate  21  and a non-volatile display material  22 . 
     The driving substrate  21  has a plurality of pixel electrodes  211 , a lower substrate  212 , and a connecting pad  213 . The material of the lower substrate  212  may be resin, ceramics, or glass. The pixel electrodes  211  are disposed on the lower substrate  212 . A control chip  214  (as shown in  FIG. 5 ) or a control circuit disposed on the lower substrate  212  is used to drive the non-volatile display material  22  with the pixel electrodes  211 , and the driving substrate  21  can be driven by an active matrix driving method or a passive matrix driving method. In the embodiment, the driving substrate  21  is driven by the active matrix driving method for example. In addition, the connecting pad  213  is disposed on a side of the driving substrate  21  facing the non-volatile display material  22 . For example, the connecting pad  213  is disposed on a side of the lower substrate  212  facing the non-volatile display material  22 . 
     The non-volatile display material  22  is disposed on a side of the driving substrate  21 . The non-volatile display material  22  may be an electrophoretic material, for example, a plurality of charged particles C and a dielectric solution L. In the embodiment, the non-volatile display apparatus  2  further includes an accommodating structure  23 , which may include a plurality of micro-cups or a plurality of microcapsules. The accommodating structure  23  in the embodiment has a plurality of micro-cups for example. The charged particles C are suspended in the dielectric solution L, and the charged particles C and the dielectric solution L are both accommodated in the micro-cups. 
     In addition, the non-volatile display apparatus  2  further includes an upper substrate  24  and a non-volatile display material  22  is disposed between the upper substrate  24  and the driving substrate  21 . The upper substrate  24  may be flexible or inflexible. The material of the upper substrate  24  may be resin, ceramics, or glass, and may or may not be the same as that of the lower substrate  21 . 
     In the embodiment, the non-volatile display apparatus  2  further includes a common electrode layer  25  that is transparent. The common electrode layer  25  is disposed opposite to the pixel electrodes  211  of the driving substrate  21  and between the non-volatile display material  22  and the upper substrate  24 . As a voltage difference is applied between the common electrode layer  25  and at least one pixel electrode  211 , the charged particle C is forced to move, such that the ambient light is reflected to present the color of the charged particle C or of the dielectric solution L. The material of the common electrode layer  25  can be, for example, indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), or zinc oxide (ZnO). 
     The non-volatile display apparatus  2  further includes a conductive element  26  that is connected to the connecting pad  213  and the common electrode layer  25 , such that the common electrode layer  25  is electrically connected to the connecting pad  213 . The conductive element  26  may be a conductive spacer (e.g. a gold ball), a conductive gel (e.g. a silver gel), a conductive adhesive tape or a wire. The conductive element  26  in the embodiment is a gold ball for example. To dispose the conductive element  26 , the non-volatile display material  22  has to be partially removed so as to connect the conductive element  26  with the connecting pad  213  and the common electrode layer  25 . In the embodiment, the partial non-volatile display apparatus  2  and the accommodating structure  23  are removed by laser. However, the accommodating structure  23  still remains outside the conductive element  26  to maintain the mechanical intensity. It is noted that the connecting pad  213  in the embodiment is disposed on a side of the driving substrate  21  facing the non-volatile display material  22 . Certainly, the connecting pad  213  may also be disposed opposite to the side of the driving substrate  21  facing the non-volatile display material  22 . If that is the case, the common electrode layer  25  may be electrically connected to the connecting pad  213  by a via of the driving substrate  21  or by the conductive element  26  that passes through or goes around the driving substrate  21 . 
     In addition, the non-volatile display apparatus  2  may further includes an adhesive layer  27 . In the embodiment, the driving substrate  21  can be adhered to the accommodating structure  23  accommodating the non-volatile display material  22  by the adhesive layer  27 . 
       FIG. 5  is a top view of the non-volatile display apparatus  2  in  FIG. 4 . With reference to  FIG. 5 , the area of the driving substrate  21  is larger than that of the upper substrate  24  because a control chip  214  or a control circuit (not shown) has to be disposed on the driving substrate  21 . Additionally, the upper substrate  24  is a convex polygon, in which each inner angle is smaller than 180 degrees. On the contrary, a concavo polygon has at least one inner angle larger than 180 degrees. The convex polygon is, for example, a rectangle, a square, or a regular polygon. In the embodiment, the upper substrate  24  is a rectangle for example. 
     In the embodiment, the pixel electrodes  211  are distributed in the X columns and Y rows and form a rectangular area R. At least partial connecting pad  213  is disposed in the rectangular area R. At least a part of the connecting pad  213  is located in the rectangular area R, and the connecting pad  213  is disposed in a corner of the rectangular area R for example. The shape of the connecting pad  213  is not limited, and it may be rectangular (as shown in  FIG. 5 ), round, or in irregular shape. Furthermore, the profile of the distribution area of the pixel electrodes  211  is concavo polygonal, which means, if the adjacent pixel electrodes  211  on the periphery of the distribution area of the pixel electrodes  211  are connected, a concavo polygon is formed because the connecting pad  213  is disposed in the partial rectangular area R. 
     With reference to  FIGS. 5 and 6 , in the embodiment, the non-volatile display film E that includes the non-volatile display material  23 , upper substrate  24  and common electrode  25  can be cut from a large-area non-volatile display film E′. The area of the large-area non-volatile display film E′ in the present invention is the same size as the area of the conventional large-area electrophoretic display material. Since the connecting pad  213  is formed by sacrificing partial area of the rectangular area R, the non-volatile display film E, i.e. the upper substrate  24 , is rectangular. Thus, the cutting speed can be enhanced while the cutting step is processed so as to save the manufacturing time. Besides, the material cost can be reduced by cutting a greater number of the non-volatile display films E in the same area. 
     As shown in  FIG. 7 , the non-volatile display apparatus  2  may further include a frame  28 , which covers the periphery of the driving substrate  21  and has an opening  281 . The rectangular area R corresponds to a display surface D 2  and at least part of the display surface D 2  is exposed from the opening  281 . In the embodiment, the size of the rectangular area R is the same as that of the display surface D 2  and the opening  281  is approximately larger than the display surface D 2 . The display surface  2  is exposed from the opening  281 , so the user can see the displayed image on the display surface  2 . 
     The part of the driving substrate  21  on which the connecting pad  213  is disposed does not have the pixel electrode  211  and the non-volatile display material  23 , therefore the user observes a non-effective display area N 2  on the display surface D 2  that corresponds to the connecting pad  213 . The non-effective display area N 2  is shown as the oblique-line part in  FIG. 7 , and the size of the non-effective display area N 2  in  FIG. 7  is bigger than the actual size for illustration only. The image in the non-effective display area N 2  will not change with the variation of the driving signal. Moreover, the display surface D 2  has a plurality of pixels P (i.e. the positions of the pixel electrodes  211  in the embodiment) that are distributed within the X columns and Y rows. Since the non-effective display area N 2  is formed, the number of the pixels (the effective display pixels) is smaller than the product of X and Y. In addition, the connecting pad  213  is disposed in the corner of the rectangular area R; hence the user can see the non-effective display area N 2  on the display surface D 2 . 
       FIGS. 8A to 8D  are different aspects of the non-volatile display apparatuses  2   a ,  2   b ,  2   c , and  2   d  in the second embodiment of the present invention. Although the frame is not shown in  FIGS. 8A to 8C , rectangular circumscriptions are used to indicate the areas of the display surfaces D 3 , D 4 , and D 5 , respectively. The positions of the non-effective display areas N 3 , N 4 , and N 5  change with the position variation of the connecting pad  213 , therefore the non-effective display areas N 3 , N 4 , and N 5  are located on a side, a corner, and an inside portion of the display surfaces D 3 , D 4 , and D 5 , respectively. The shapes of the non-volatile display areas N 3 , N 4 , and N 5  are not limited and can be modified according to the demands of manufacturing process. For example, the non-effective display area N 3  of the non-volatile display apparatus  2   a  may have an arc (as shown in  FIG. 8A ) and is located in a corner of the display surface D 3 . Alternatively, the non-effective display area N 4  of the non-volatile display apparatus  2   b  may locate inside the display surface D 4 . Additionally, the non-effective display area N 5  of the non-volatile display apparatus  2   c  is located on a side of the display surface D 5 . 
     In addition, the frame in the embodiment can cover the non-effective display area. As shown in  FIG. 8D , the non-volatile display apparatus  2   d  has a frame  28 ′, which has an opening  281 ′ that is a concavo polygon (as shown in  FIG. 8D ) or in irregular shape, rather than a rectangle (or a convex polygon). A part of the frame  28 ′ is disposed on the projection direction of the connecting pad  213 , i.e. the frame  28 ′ has a protruding part that covers at least a part of the connecting pad  213  (e.g. completely covers the connecting pad  213  as shown in  FIG. 8D ), and blocks the non-effective display area N 6 , such that as the user view the image through the opening  281 ′, s/he will not see the non-effective display area N 6 . 
     To sum up, a non-volatile display apparatus according to the present invention is to dispose the connecting pad in the pixel electrodes-distributed rectangular area formed by the X columns and Y rows, such that waste parts do not have to be reserved when the non-volatile display film is cut, so as to greatly enhance the cutting utility and cutting speed, hence reduce the material cost. 
     Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.