Electrical connectors – With relatively guided members and intermediate pliable... – Relatively movable about axis
Reexamination Certificate
2001-04-17
2003-05-27
Luebke, Renee (Department: 2833)
Electrical connectors
With relatively guided members and intermediate pliable...
Relatively movable about axis
Reexamination Certificate
active
06568947
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for electrically connecting a number of relatively movable parts using a flexible printed circuit. It finds particular utility in folding electronic apparatus such as personal organisers, laptop computers or mobile telephones.
It is desirable to be able to manufacture a number of portable electrical devices such that they can be folded into a relatively flat, minimal volume configuration when not in use, and unfolded, possibly to reveal further functional parts, when in use. As an example, it is convenient for a user of a portable telephone to be able to carry it unobtrusively about his person. However, small telephones can suffer from problems with smaller displays, smaller keypads, and reduced distance between loudspeaker and microphone which can adversely affect audio quality in each direction of communication. However, if a folding configuration is adopted for the telephone, a larger surface area can be made available for a given volume, when compared to a non-folding configuration. This mitigates the problems referred to above. For instance, a keypad and display can be concealed inside the folded telephone, to be revealed when the telephone is unfolded.
However, a problem with foldable electronic devices is how to electrically connect the two or more sections to each other. Known solutions have used wires and cables, either individually or in the form of ribbon cable, to connect the sections. However, such wires can be too bulky and inflexible to be used in today's miniature devices. The preferred method of connection now utilises a flexible connector, such as a flexible printed circuit board (PCB) to provide electrical connection.
Flexible PCBs consist of one or more insulating substrates onto which one or more layers of conductive tracks are printed, with the layers of conductive tracks being insulated from each other by respective layers of the substrate material.
A problem with such an arrangement, however, arises over the lifetime of the apparatus in which it is incorporated. A laptop computer, or a foldable telephone is generally designed to have a life-span of several years. As part of the life calculations for such a device, a certain number of folding and unfolding operations are required. It is not unusual for the number of such operations to be in the range of hundreds of thousands to greater than a million (100,000→>1,000,000). Such a large number of iterations places a great deal of stress on the moving parts of the folding apparatus and can result in malfunction before the specified number of operations has been reached.
FIGS. 1
a
and
1
b
shows the simplest possible method of using a flexible PCB to connect two halves of a foldable device, such as a telephone. In this case, rigid PCB
110
in a first half of the telephone
100
is connected to rigid PCB
120
in a second half of the telephone
100
by flexible PCB
130
. The flexible PCB
130
passes through the hinge mechanism
140
holding the two halves of the telephone together.
As the telephone is opened, as shown in
FIG. 1
b,
the flexible PCB moves through a large angle (generally in the range 0-180°). As the telephone is opened and closed repeatedly over many such cycles, the cumulative stress on the flexible PCB can cause damage to the conductive tracks. Also, this technique requires a large ungathered surplus of flexible PCB to be contained within the hinge mechanism in the closed position. This increases the chances of the flexible PCB ‘kinking’, and so damaging the connections it carries. It also requires the internal dimensions of the hinge mechanism to be larger than would otherwise be required in order to accommodate the excess flexible PCB.
The apparatus shown at
FIGS. 1A and B
is a rather simplistic view of how such interconnection may be achieved in practice. The hinge mechanism is generally more complicated, and may incorporate such additional elements as self-opening mechanism, locking mechanism or damping mechanisms. All these other elements make the passage of the flexible PCB through the hinge significantly more complicated. One way of overcoming such difficulties is disclosed in European patent application EP0961370. This patent application describes a flexible connection between two halves of a telephone which requires the flexible PCB to perform a helical twist along its length.
There is a possibility, in implementing such a system, that the flexible PCB is able to chafe against itself inside the hinge mechanism. Such chafing is then liable to adversely affect the electrical connection between the two halves of the telephone.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, there is provided a portable electronic apparatus comprising first and second portions, which are arranged such that the two portions are relatively movable between a first configuration and a second configuration, and are electrically connected together by a flexible electrical connector, wherein the route of the connector between the two portions is impeded by an obstacle, such that in the first configuration, the connector is constrained to follow a first route, and in the second configuration, the connector is constrained to follow a second, different, route.
According to a second aspect of the present invention, there is provided a portable electronic apparatus comprising first and second portions arranged in relatively movable connection via a hinge, the first and second portions being electrically connected via a flexible connector, wherein the flexible connector is routed through the hinge via an obstruction arranged to move with one of the portions, the obstruction taking the form of a plurality of structures projecting along lines substantially parallel to the axis of the hinge, about which structures the connector is routed, and at a given relative position of the two portions, one of the plurality of structures plays no part in the routing of the connector.
An advantage of this invention is the provision of a means of reliable electrical interconnection between two parts of an apparatus which are movable in relation to each other.
Another advantage of this invention is that the stress and strain to which the flexible connector is subjected throughout the opening and closing operations of the portable apparatus are kept at acceptable, determinable levels. This is achieved by routing the connector through the hinge in such a way that the connector follows a defined route, which alters as the configuration of the apparatus alters, and maintains a substantially constant length for all relative positions of the apparatus.
The constant length route is achieved through careful selection of a series of obstacles which act to guide the connector on a defined routed through the hinge. The positions and sizes of the obstacles are carefully chosen so that the route taken by the connector does not alter its length significantly in moving from a fully open to a fully closed configuration.
An embodiment of the invention guides the connector around a series of projections attached to a plate arranged so that the plate rotates in accordance with the position of the hinge. In this way, the exact route taken by the flexible connector varies in relation to the relative position of the parts of the foldable apparatus. The plate may be made to move in relation to the hinge position by attaching it to one portion of the apparatus.
An embodiment of the invention employs three cylindrical projections disposed across the diameter of a circular plate, and arranged to extend longitudinally in a direction parallel to the axis of rotation of the two portions. The connector is routed through the projections such that in one extreme configuration, the connector contacts opposing sides of adjacent projections.
Conveniently, the projections are arranged to be disposed within a spool which may be fitted into the hinge mechanism of the apparatus.
At one extreme of movement of the two parts, all projections play a part in
Antonelli Terry Stout & Kraus LLP
Figueroa Felix D.
Luebke Renee
Nokia Mobile Phone Limited
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