Abstract:
A dual-display panel module has a shared ASIC chip. A primary-display panel module provides obverse-side image display, a secondary-display panel module provides reverse-side image display, a connector electrically connects the primary-display panel and second-display panel, and a driver operatively is coupled to the primary display module and secondary display module, wherein the driver is supported in electrical connections the primary display module and the secondary display modules via the connector.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a dual-display device and more particularly to a dual-display panel module with one ASIC chip shared between a primary-display panel module and a secondary-display panel module.  
           [0003]    2. Description of the Related Art  
           [0004]    In current flat display technology, dual-display LCDs have been developed for displaying images and characters on two LCD panels. Dual-display technology is applied mainly in small-size LCDs for folding mobile phones and handheld computers. In general, a dual-display panel module is composed of a primary-display panel module, a secondary-display panel module and a backlight module shared therebetween, thus having the advantages of being thin and light and requiring fewer components.  
           [0005]    [0005]FIG. 1 is a cross-section of a conventional dual-display panel module  1  used in an amorphous silicon (a-Si) TFT-LCD device, in which a primary-display panel module  1 M has a larger display area and a secondary-display panel module  1 S with a smaller display area. The dual-display panel module is composed of a primary-display panel module  1 M for providing obverse-side image display, a secondary-display panel module  1 S for providing reverse-side image display, and a backlight module  1 L shared therebetween. The backlight module  1 L includes a light source for the primary-display panel module  1 M and the secondary-display panel module  1 S, and a light source module  1 L for improving light intensity and light uniformity.  
           [0006]    The primary-display panel module  1 M comprises a first LCD panel  10 , an upper polarizer  12 I and a lower polarizer  12 II, in which the first LCD panel  10  is composed of an upper glass substrate, a lower glass substrate, and a liquid crystal layer. The secondary-display panel module  1 S comprises a second LCD panel  20 , an upper polarizer  22 I and a lower polarizer  22 II, in which the second LCD panel  20  is composed of an upper glass substrate, a lower glass substrate, and a liquid crystal layer. Adjacent to the first LCD panel  10 , the light source module comprises a first prism  14 I, a second prism  14 II and a diffusion sheet  16 . Adjacent to the second LCD panel  20 , the light source module comprises a first prism  24 I, a second prism  24 II and a diffusion sheet  26 . Also, the light source module comprises a light-guide plate (LGP)  18  and a transflective sheet  28  sandwiched between the two diffusion sheets  16  and  26 .  
           [0007]    In the chip scale package technology for the dual-display panel module, a chip-on-glass (COG) method is employed to assemble driving chips on the glass substrate. Thus, for the primary-display panel module  1 M, a plurality of driving chips  30 A is formed on an extended portion  11  of the glass substrate of the first LCD panel  10 . Also, for the secondary-display panel module  1 S, a plurality of driving chips  30 B is formed on an extended portion  21  of the glass substrate of the second LCD panel  20 . Moreover, an ASIC (Application Specific Integrated Circuit) chip and peripheral IC components can be connected to the panel through a COF (chip on flex) method. Thus, for the primary-display panel module  1 M, a first ASIC chip  34 A is connected to the glass substrate of the first LCD panel  10  through a first FPCB (flexible printed circuit board)  32 A. For the secondary-display panel module  1 S, a second ASIC chip  34 B is connected to the glass substrate of the second LCD panel  20  through a second FPCB (flexible printed circuit board)  32 B.  
           [0008]    [0008]FIG. 2 is a cross-section of a conventional dual-display panel module  100  used in a low-temperature polysilicon (LTPS) TFT-LCD device, in which a primary-display panel module  100 M and a secondary-display panel module  100 S have identical display areas. The dual-display panel module  100  is composed of a primary-display panel module  100 M for providing obverse-side image display, a secondary-display panel module  100 S for providing reverse-side image display, and a backlight module  100 L shared therebetween. The backlight module  100 L includes a light source for the primary-display panel module  100 M and the secondary-display panel module  100 S, and a light source module  100 L for improving light intensity and light uniformity. The dual-display panel module  100  shown in FIG. 2 is substantially similar to that of the dual-display panel module  1  shown in FIG. 1, except for the integration mode of the driving chips. Since the electron mobility is faster in the LTPS TFT-LCD, a part of the driving chips is integrated onto the glass substrate, which is favorable to reduce the required area and the amount of components on the PCB, and simplify the connecting wires between the driving chips and the panel electrodes.  
           [0009]    In accordance with the dual-display panel modules shown in FIG. 1 and FIG. 2, the primary-display panel module and the secondary-display panel module are driven by the first ASIC chip  34 A and the second ASIC chip  34 B, respectively, and then connected to a system board (not shown). The requirement of the two ASIC chips  34 A and  34 B, however, requires considerable power consumption and increased production cost, and is unfavorable for reducing the component area and the amount of components on the FPCB.  
         SUMMARY OF THE INVENTION  
         [0010]    The present invention is directed to an electronic device incorporating a dual-display panel module that shares a driver by operatively coupling the driver to a common connection between two displays. The dual-display panel module includes a primary-display panel module and a secondary-display panel module. In one embodiment, the connector electrically connects to the respective ends of the primary and secondary display panels. Via this electrical connection, electrical traces are supported, which are electrically coupled to the outputs of the driver. The common driver facilitates control of both primary and secondary display panels. In one embodiment, the driver is an ASIC formed on the connector by a COF method. Accordingly, the present invention reduces power consumption, decreases production cost, and additionally reduces the component area and the amount of components on a FPCB.  
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0011]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings, given by way of illustration only and thus not intended to be limitative of the present invention.  
         [0012]    [0012]FIG. 1 is a cross-section view of a conventional dual-display panel module used in an amorphous silicon (a-Si) TFT-LCD device.  
         [0013]    [0013]FIG. 2 is a cross-section view of a conventional dual-display panel module used in a low-temperature polysilicon (LTPS) TFT-LCD device.  
         [0014]    [0014]FIG. 3 is a schematic drawing of an electronic device in accordance with one embodiment of the present invention.  
         [0015]    [0015]FIG. 4 is a cross-section view of a dual-display panel module according to the first embodiment of the present invention.  
         [0016]    [0016]FIG. 5 is a cross-section view of a dual-display panel module according to the second embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    [0017]FIG. 3 is a schematic drawing of an electronic device  210  in accordance with one embodiment of the present invention. The electronic device  210  can be, for example, a mobile phone, a hand-held computer and others. A representative folding type mobile phone is shown in FIG. 3. Even so, the teachings may be further applied to any form of display device with the dual-display module. The electronic device  210  includes a dual-display module  220 , a controller  230  for controlling operation of the dual-display module  220  and other components, such as keypad. Symbol  221  denotes the main display region, symbol  222  the auxiliary display region and symbol  225  the outer housing. According to signals (or data) from the controller  230 , the message of the auxiliary display region  222  is displayed when the housing  225  is shut. Contrarily, the message of the main display region  221  is displayed when the housing  225  is open.  
         [0018]    [0018]FIG. 4 is a cross-section view of a dual-display panel module  300  according to the first embodiment of the present invention. The dual-display panel module  300  comprises a primary-display panel module  300 M, a secondary-display panel module  300 S and a backlight module  300 L shared between the two panel modules  300 M and  300 S. The primary-display panel module  300 M is used to provide obverse-side image display, and the secondary-display panel module  300 S is used to provide reverse-side image display. The backlight module  300 L includes a light source and a lightsource module  300 L. The light source provides the required light to the primary-display panel module  300 M and the secondary-display panel module  300 S. The lightsource module  300 L is used to improve light intensity and light uniformity. The dual-display panel module  300  can be incorporated in a number of electronic devices, including flat display devices, such as an LCD device, a PDP device, and an OLED device, thus a display material layer may be a liquid crystal layer, a fluorescent layer, or an organic luminescent layer. Also, the area, corresponding location and functions of the primary-display panel module  300 M and the secondary-display panel module  300 S are not limited in the present invention.  
         [0019]    [0019]FIG. 4 illustrates a dual-display panel module  300  used in an amorphous silicon (a-Si) TFT-LCD device, in which the display area of the primary-display panel module  300 M is larger than that of the secondary-display panel module  300 S. The primary-display panel module  300 M comprises a first LCD panel  340 , an upper polarizer  342 I and a lower polarizer  342 II. The first LCD panel  340  is composed of an upper glass substrate, a lower glass substrate and a liquid crystal layer, in which switching elements (such as a TFT array), pixel electrodes, LC alignment layers and color filters are formed. The secondary-display panel module  300 S comprises a second LCD panel  350 , an upper polarizer  352 I, and a lower polarizer  352 II. The second LCD panel  350  is composed of an upper glass substrate, a lower glass substrate and a liquid crystal layer, in which switching elements (such as a TFT array), pixel electrodes, LC alignment layers and color filters are completed.  
         [0020]    The lightsource module  300 L is disposed between the primary-display panel module  300 M and the secondary-display panel module  300 S. Adjacent to the lower polarizer  342 II of the first LCD panel  340 , the lightsource module  300 L comprises a first prism  344 I, a second prism  344 II and a diffusion sheet  346 . Also, adjacent to the lower polarizer  352 II of the second LCD panel  350 , the light-source module  300 L comprises a first prism  354 I, a second prism  354 II and a diffusion sheet  356 . Moreover, the light-source module  300 L comprises a light-guide plate (LGP)  348  and a transflective sheet  358  sandwiched between the two diffusion sheets  346  and  356 . The light-guide plate  348  is used to transform an incident light into an area light. The transflective sheet  358  is used to provide reflection from the bottom of the light-guide plate  348 . The diffusion sheets  346  and  356  and the prisms  344  and  354  are used to improve the characteristics of the light emitted from the light-guide plate  348 .  
         [0021]    In the chip scale package technology for dual-display panel modules, a chip-on-glass (COG) method is employed to assemble driving chips on the glass substrate. Thus, for the primary-display panel module  300 M, a plurality of driving chips  360 A is formed on an extended portion  341  of the glass substrate of the first LCD panel  340 . Also, for the secondary-display panel module  300 S, a plurality of driving chips  360 B is formed on an extended portion  351  of the glass substrate of the second LCD panel  350 .  
         [0022]    Moreover, a driver, such as an ASIC (Application Specific Integrated Circuit) chip and peripheral IC components, can be connected to the panels through a COF (chip on flex) packaging method. The feature of the first embodiment of the present invention is to provide one ASIC chip  364  shared between the primary-display panel module  300 M and the secondary-display panel module  300 S. Thus, the ASIC chip  364  and the peripheral IC components are formed in relation to a connector that electrically connects the primary and secondary panels, therefore facilitating coupling the ASIC to the first and second display panels. The connector can be substantially flexible, such as a FPCB (flexible printed circuit board)  362 . The two ends of the FPCB  362  are connected to the glass substrates of the first LCD panel  340  and the second LCD panel  350 , respectively. The ASIC (Application Specific Integrated Circuit) is an IC product created in accordance with user-defined circuit design, which integrates multiple traditional-chip circuits on a chip to substantially reduce product defect rates. Currently, various kinds of ASIC chips have been developed, including an image/drafting chip, an LCD panel control chip, and an LCD display control chip.  
         [0023]    The COF packaging method is a flip chip bonding method used on a FPCB, in which a nonconductive glue material without halogens and lead elements is provided on the FPCB, and then the cured state of the nonconductive glue material has a shrink stress that creates a connection between the IC chip and the electrode of the FPCB.  
         [0024]    In dual-display panel modules, the ASIC chip  364  and the peripheral IC components are shared between the primary-display panel module  300 M and the secondary-display panel module  300 S through the FPCB  362 , and then connected to a system board (not shown). The dual-display panel module has a shared ASIC chip  364 , thus reducing power consumption, module cost, required area on the FPCB and components required thereby. Also, the original space required to dispose an ASIC chip and peripheral components for the secondary-display panel module  300 S is effectively reduced.  
         [0025]    [0025]FIG. 5 is a cross-section of a dual-display panel module  400  according to the second embodiment of the present invention. The dual-display panel module  400  is used in a low-temperature polysilicon (LTPS) TFT-LCD device, in which a primary-display panel module  400 M and a secondary-display panel module  400 S have an identical display area. The dual-display panel module  400  shown in FIG. 4 is substantially similar to that of the dual-display panel module  300  shown in FIG. 3, thus the similar portions are omitted herein. The dissimilar portion is the integration mode of the driving chips. Since the electron conduction is faster in the LTPS TFT-LCD, a part of the driving chips is integrated into the interior of the glass substrate, which is favorable to reduce the required area and the amount of components on the PCB, and simplify the connecting wires between the driving chips and the panel electrodes. The feature of the second embodiment of the present invention is to provide one ASIC chip  464  shared between the primary-display panel module  400 M and the secondary-display panel module  400 S, thus reducing power consumption, module cost, the required area on the FPCB  462  and the required components on the FPCB  462 . Also, the original space required to dispose an ASIC chip  464  and peripheral components for the secondary-display panel module  400 S is effectively reduced.  
         [0026]    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.