Patent Publication Number: US-2007096181-A1

Title: Flexible memory module

Description:
This application claims the priority benefit of Taiwan patent application number 094218593 filed on Oct. 27, 2005.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a memory module and more particularly, to such a memory module, which has a flexible board extension extended from one side of the substrate to carry added memory chips without extra installation space.  
      2. Description of the Related Art  
      Following fast development of electronic industry and electronic technology, more and more advanced electronic products are used in our daily life to improve the working efficiency and the living quality. Many different electronic products, more particularly, computers, communication apparatus and consumer electronics use different memory devices for storing and transferring data.  
      Many memory modules have been disclosed and have appeared on the market. These memory modules include SIMM (Single In-Line Memory Module), DIMM (Dual In-Line Memory Module), RIMM (Direct Rambus Memory Module), and etc. These memory modules may carry 8 or 4 memory chips on one single side, or 16 memory chips on two sides. When wishing to increase the memory capacity of a memory module, the memory capacity of each memory chip must be upgraded. Further, following the development of manufacturing techniques, electronic products are made to have light, thin, short and small characteristics. In order to fit small size electronic products, SO DIMM (Small Outline Dual In-Line Memory Module) is disclosed. This memory module carries only 4 memory chips on one side. This design has no space for extra memory chips. Increasing the memory capacity of this design of memory module must firstly increase the memory capacity of each individual memory chip.  
     SUMMARY OF THE INVENTION  
      The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a flexible memory module, which allows installation of added memory chips without increasing the installation space. To achieve this and other objects of the present invention, the flexible memory module comprises a substrate, which is formed of a printed circuit board and electrically connectable to a insertion slot of a connector, a flexible board extension, which is fixedly provided at the rear side of the substrate and turned backwards and covered over the substrate to reduce surface space occupation after connection of the substrate to the insertion slot of the connector, and a plurality of memory chips respectively installed in the substrate and the flexible board extension. In an alternate form of the present invention, the flexible memory module comprises two substrates (printed circuit boards), a flexible connection strip connected between the substrates, and memory chips respectively installed in the substrate. The flexible connection strip allows the two substrates to be arranged in a stack after connection of the flexible memory module to a insertion slot of a connector. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a flexible memory module in accordance with a first embodiment of the present invention.  
       FIG. 2  is a schematic drawing showing an installation example of the flexible memory module according to the first embodiment of the present invention (I).  
       FIG. 3  is a schematic drawing showing an installation example of the flexible memory module according to the first embodiment of the present invention (II).  
       FIG. 4  is a schematic drawing showing an installation example of the flexible memory module according to the first embodiment of the present invention (III).  
       FIG. 5  is a schematic drawing showing an installation example of the flexible memory module according to a second embodiment of the present invention (I).  
       FIG. 6  is a schematic drawing showing an installation example of the flexible memory module according to the second embodiment of the present invention (II).  
       FIG. 7  is an elevational view of a flexible memory module in accordance with a third embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring to  FIG. 1 , a flexible memory module  1  in accordance with a first embodiment of the present invention is shown comprised of a substrate  11 , a flexible board extension  12 , and a plurality of memory chips  13 .  
      The substrate  11  according to this embodiment is a printed circuit board having a control circuit (not shown) and a plurality of contacts  111  at one side.  
      The flexible board extension  12  is connected to one side of the substrate  11  away from the contacts  111 , carrying a control circuit (not shown).  
      The memory chips  13  are respectively installed in the substrate  11  and the flexible board extension  12 . Further, the memory chips  13  can be DRAM, EDO DRAM, SDRAM, DDR SDRAM, DDRII SDRAM, DDRIII SDRAM, SRAM or Flash chips.  
      Referring to FIGS.  2 ˜ 4 , during the use of the flexible memory module  1 , the substrate  11  is inserted into a insertion slot  22  of a connector  2  to force the contacts  111  of the substrate  11  into contact with respective contacts in the insertion slot  22  of the connector  2 . After connection of the substrate  11  to the insertion slot  22  of the connector  2 , the user can then bend the flexible board extension  12  backwards toward the connector  2  and cover the flexible board extension  12  on the top side of the substrate  11 , thereby reducing surface space occupation. Because the substrate  11  and flexible board extension  12  of the flexible memory module  1  can be arranged in a stack, the invention doubles the amount of memory chips  13  without increasing much the installation space. Therefore, the flexible memory module  1  of the present invention fits the requirement for an electronic device having light, thin, short and small characteristics.  
       FIGS. 5 and 6  show a flexible memory module in accordance with a second embodiment of the present invention. This embodiment is substantially similar to the aforesaid first embodiment with the exception that the flexible board extension  12  has a retaining hole  121  on the remote side (the side away from the contact  111 ) corresponding to a protruding point  21  of the connector  2 . When turned the flexible board extension  12  backwards toward the connector  2  over the top side of the substrate  11 , the retaining hole  121  is forced into engagement with the protruding point  21  at the connector  2 , and therefore the flexible board extension  12  is kept overlapped on the substrate  11 .  
      In the aforesaid second embodiment, the flexible board extension  12  is made to have the retaining hole  121  for securing to the protruding point  21  at the connector  2 . Alternatively, snap fastener or any of a variety of other fastening means may be used to detachably secure the free end of the flexible board extension  12  to the connector  2 .  
       FIG. 7  shows a flexible memory module  3  in accordance with a third embodiment of the present invention. According to this embodiment, the flexible memory module  3  comprises a first substrate  31 , which has a control circuit (not shown) and a plurality of contacts  311  at one side, a second substrate  33 , which has a control circuit (not shown), a flexible connection strip  32 , which has a control circuit (not shown), a first lateral side fixedly connected to one side of the first substrate  31  away from the contacts  311  and a second lateral side fixedly connected to one side of the second substrate  33 , and a plurality of memory chips  34  respectively installed in the first substrate  31  and the second substrate  33 .  
      By means of the flexible connection strip  32 , the first substrate  31  and the second substrate  33  can be turned toward each other and arranged in a stack to reduce the installation space. Further, a male fastening member (not shown) and a female fastening member (not shown) may be respectively provided at the first substrate  31  and the second substrate  32  and fastened to each other to hold the flexible memory module  3  in a folded status.  
      Similar to the aforesaid first embodiment, the memory chips  34  of this third embodiment can be DRAM, EDO DRAM, SDRAM, DDR SDRAM, DDRII SDRAM, DDRIII SDRAM, SRAM or Flash chips.  
      A prototype of flexible memory module has been constructed with the features of FIGS.  1 ˜ 7 . The flexible memory module functions smoothly to provide all of the features discussed earlier.  
      Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.