Classifications

• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
  • G06F1/16—Constructional details or arrangements
  • G06F1/1613—Constructional details or arrangements for portable computers
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
  • G06F1/16—Constructional details or arrangements
  • G06F1/1613—Constructional details or arrangements for portable computers
  • G06F1/1626—Constructional details or arrangements for portable computers with a single-body enclosure integrating a flat display, e.g. Personal Digital Assistants [PDAs]
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
  • G06F1/16—Constructional details or arrangements
  • G06F1/1613—Constructional details or arrangements for portable computers
  • G06F1/1633—Constructional details or arrangements of portable computers not specific to the type of enclosures covered by groups G06F1/1615 - G06F1/1626
  • G06F1/1656—Details related to functional adaptations of the enclosure, e.g. to provide protection against EMI, shock, water, or to host detachable peripherals like a mouse or removable expansions units like PCMCIA cards, or to provide access to internal components for maintenance or to removable storage supports like CDs or DVDs, or to mechanically mount accessories
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/02—Constructional features of telephone sets
  • H04M1/0202—Portable telephone sets, e.g. cordless phones, mobile phones or bar type handsets
  • H04M1/026—Details of the structure or mounting of specific components
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/02—Constructional features of telephone sets
  • H04M1/18—Telephone sets specially adapted for use in ships, mines, or other places exposed to adverse environment
  • H04M1/185—Improving the shock resistance of the housing, e.g. by increasing the rigidity
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F2200/00—Indexing scheme relating to G06F1/04 - G06F1/32
  • G06F2200/16—Indexing scheme relating to G06F1/16 - G06F1/18
  • G06F2200/163—Indexing scheme relating to constructional details of the computer
  • G06F2200/1633—Protecting arrangement for the entire housing of the computer
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/02—Constructional features of telephone sets
  • H04M1/0202—Portable telephone sets, e.g. cordless phones, mobile phones or bar type handsets
  • H04M1/026—Details of the structure or mounting of specific components
  • H04M1/0262—Details of the structure or mounting of specific components for a battery compartment
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/02—Constructional features of telephone sets
  • H04M1/0202—Portable telephone sets, e.g. cordless phones, mobile phones or bar type handsets
  • H04M1/026—Details of the structure or mounting of specific components
  • H04M1/0266—Details of the structure or mounting of specific components for a display module assembly
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/02—Constructional features of telephone sets
  • H04M1/0202—Portable telephone sets, e.g. cordless phones, mobile phones or bar type handsets
  • H04M1/026—Details of the structure or mounting of specific components
  • H04M1/0277—Details of the structure or mounting of specific components for a printed circuit board assembly

Definitions

• a portable electronic device A portable electronic device
• the present invention relates to the field of portable electronic devices more particularly to the shock-resistance of such devices,
• portable electronic devices such as PDAs, cell phones and digital cameras continue to become more widespread as they shrink in size while incorporating additional features at the same time.
• PDAs personal digital assistants
• portable electronic devices are prone to being dropped or otherwise knocked in use, with the resulting shock to the components being a major cause of damage to and failure of such portable electronic devices. Therefore, it is desirable that portable electronic devices have some degree of shock resistance so that they do not fail when dropped or knocked.
• the working components e.g. LCD, memory devices, battery
• an external housing which serves as physical protection for the components.
• failure of the components in the housing can still occur if the housing is subjected to a force, not only where the housing itself breaks, but also in some cases even if the housing remains intact
• a portable electronic device comprising: a housing; a frame internal of the housing; a printed circuit board and a display mounted on and supported by the frame, the frame having a stiffness and/or a spring constant higher than that of the circuit board or the display.
• the printed circuit board is mounted on a first side of the frame and the display is mounted on the second opposing side of the frame.
• a battery which is preferably of flat or pancake-like dimensions may be mounted on the frame, preferably be being affixed to the printed circuit board. Where the battery has a plurality of sides of differing surface area, the side of largest surface area is preferably affixed to the printed circuit board.
• the frame preferably forms a backbone for the components mounted thereon.
• the frame may be formed from metal, preferably a magnesium alloy or may be formed from a non-metallic material such as Fibre Reinforced Plastic or Carbon Fibre Reinforced Plastic.
• the display is preferably a liquid crystal display.
• a portable electronic device comprising a housing; a printed circuit board and a battery disposed within the housing, wherein the battery is attached to the printed circuit board to provide support for the printed circuit board.
• the invention of the second aspect preferably includes a frame, to which the circuit board is attached, the frame may be stiffer than the circuit board and the frame and battery may be attached to opposed sides of the circuit board.
• a frame internal to the housing of a portable electronic device is provided.
• the internal frame is of substantial stiffness and functions as a backbone which supports working components mounted on the frame, in particular a display and a pcb.
• This approach departs from conventional designs, where in order to minimise the size of the portable electronic device, the external housing is used as an exoskeletal structure providing most of the support for the device components and a mounting structure for fastening together the various components comprising the device.
• Figure 1 is a cross-sectional view of an embodiment of the invention, being a personal data assistant (PDA) fitted with an internal frame;
• PDA personal data assistant
• Figure 2 is an exploded three-dimensional view. of the embodiment of Figure 1.
• the inventors have recognised that shock load transmitted through a housing can contribute to the failure of portable electronic devices.
• the inventors have identified two additional failure modes arising from transmitted shock load. Firstly, the transmitted shock load can cause distortion of the housing , which distortion is transmitted to the working components in a portable electronic device. Since LCDs are generally brittle and exhibit very poor elastic limits, distortion can result in fracture or multi-hued distortion (called rainbowing) of the LCD.
• the transmitted shock pulses can cause vibration waves to be set up in the housing, which are transmitted to the components. PCBs are particularly vulnerable to vibration in view of the many soldered joints between components which can easily be dislodged resulting in failure.
• FIGS 1 and 2 illustrate a portable electronic device 100 in accordance with one embodiment of the invention.
• a rigid internal frame 150 is provided.
• the frame has a peripheral oblong frame member and one cross-member both of 'L'-shape cross-section and includes threaded openings to receive screws to allow attachment of components of the device.
• the internal frame 150 supports a LCD 140 and a PCB 130 which includes processing circuitry of the device and driving circuitry.
• the LCD and PCB are securely mounted onto the internal frame by screws or suchlike. In the preferred embodiment shown in Figures 1 and 2, the LCD and PCB are mounted on opposed sides of the frame.
• the internal frame serves as a "backbone" to the components to lower the likelihood of failure and therefore improve the shock resistance of the PDA by suppressing the distortion of the LCD and reducing the amplitude of vibration of the PCB during a shock event.
• the internal frame In order to provide adequate support for the LCD and PCB during a shock, the internal frame has to be stiffer and/or have a higher spring constant than the components it is supporting. In general, the higher spring constant k the frame has, the better it's ability to suppress distortion of the LCD and resist vibration.
• the internal frame is made from a magnesium (Mg) alloy such as AZ91 D, a commonly used magnesium alloy for thixotropic die casting, includes 9% of Al and 1 % of Zn. which is relatively lightweight and has higher strength/stiffness.
• Mg magnesium
• Other transition metal alloys such as Al and Ti may be used as can non- metals, e.g. FRP (Fibre Reinforced Plastic) or CFRP (Carbon Fibre Reinforced Plastic).
• the stiffness required would also depend on the environment where the portable device is to be used. Generally industrial devices are subjected to more stringent standards and the portable devices designed for use in an industrial environment would have to survive higher shocks. Therefore, industrial portable electronic devices generally require stiffer internal frames.
• the resulting combination of the PCB 130, internal frame 150 and LCD 140 gives rise to a unitary structure wherein the movements of the components are, essentially, synchronised.
• the described embodiment also has the advantage of combining shock protection for several components on one structure. By eliminating the need to have separate shock protection structures for the LCD and the PCB, further miniaturisation of the whole device is facilitated.
• the working components of the PDA are contained within an external protective housing comprising a top housing 101 and a bottom housing 120 which are sealed together through a main gasket 190.
• Three openings are provided on the top housing: one for viewing the LCD screen, one for housing the key pad 110 and one for receiving the I/O port 180.
• the internal frame 150 (with the PCB 130 and LCD 140 mounted on opposed sides of the frame) is securely mounted onto the top housing 1 (e.g. by screws or other fastening means) to form a larger unitary structure.
• the touch panel 111 is applied to the LCD and enwrapped by the display gasket 160 together with the LCD integrally.
• the display gasket is formed from rubber material and is chosen such that they help to dampen any shock by absorbing some of the shock energy arising from the impact and also to seal the water around the opening for LCD screen at the same time. This improves the shock absorption characteristics of the housing as a whole so that the shock transmitted to the internal components such as the LCD and circuit board can be reduced.
• the LCD and the battery are typically the main components that have a large volume and heavy weight.
• the battery is mounted next to the PCB or in a separate compartment.
• the strength and spring constant of the unitary structure comprising the PCB 3, internal frame 150 and LCD 140 is increased by attachment of a battery 170 to the PCB 130, preferably by adhesive.
• the battery 170 is mounted onto the PCB 130 such that the internal frame 150 and battery 170 together sandwich and support the PCB.
• the battery is of flat or pancake-like dimensions, with the face of the battery of largest surface area being attached to the PCB to provide support over as large a surface area of the PCB as possible.
• One additional advantageous effect of connecting the LCD, battery, PCB and frame together in a unitary structure is that the structure will have a single identifiable centre of gravity. This allows the relative placement of the components to be chosen to position the centre of gravity relative to the housing to minimize the effects of shock. Generally having the centre of gravity of the unitary structure and the housing the same or similar will reduce the effects on the unitary structure of a shock applied to the housing.
• the embodiment of the invention described is not to be construed as limitative.
• the invention is also relevant to any other types of portable electronic devices having a display for example and without limitation to transmitting and/or receiving devices such as cell phones, optical devices such as digital cameras, measuring and sensing devices such as electronic cable finders and spirit levels, portable data processing devices such as computers and apparatus for processing sounds and/or images, such as portable dvd players or televisions.
• the battery need not be mounted on the pcb but can be disposed separately in the housing.
• the LCD and PCB can be mounted onto the same side of the internal frame, next to each other or with the LCD being mounted on the PCB in a sandwich arrangement.

Landscapes

• Engineering & Computer Science (AREA)
• Theoretical Computer Science (AREA)
• Computer Hardware Design (AREA)
• General Engineering & Computer Science (AREA)
• Human Computer Interaction (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Signal Processing (AREA)
• Casings For Electric Apparatus (AREA)
• Devices For Indicating Variable Information By Combining Individual Elements (AREA)
• Liquid Crystal (AREA)
• Telephone Set Structure (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (2)

Family

ID=34976039

Family Applications (1)

Country Status (3)

Cited By (11)

Families Citing this family (17)

Family Cites Families (14)

• 2005
  • 2005-02-28 US US10/592,720 patent/US20080094787A1/en not_active Abandoned
  • 2005-02-28 JP JP2007503866A patent/JP2007537503A/ja not_active Withdrawn
  • 2005-02-28 WO PCT/SG2005/000058 patent/WO2005086607A2/en not_active Ceased

Also Published As

Similar Documents

Legal Events