U.S. patent application number 13/278692 was filed with the patent office on 2012-06-21 for in-situ fold-assisting frame for flexible substrates.
This patent application is currently assigned to BIOTRONIK SE & CO. KG. Invention is credited to Anthony A. Primavera.
Application Number | 20120151758 13/278692 |
Document ID | / |
Family ID | 46052340 |
Filed Date | 2012-06-21 |
United States Patent
Application |
20120151758 |
Kind Code |
A1 |
Primavera; Anthony A. |
June 21, 2012 |
In-Situ Fold-Assisting Frame for Flexible Substrates
Abstract
A method for manufacturing devices built on flexible substrates
employs an in-situ, fold-assisting device frame. The fold-assisting
frame conforms to a portion of the interior volume within the
package, such that one or more pivoting members of the frame may be
used as an in-situ, bending jig, in place of conventional bending
equipment, to support and fold the planar flexible substrate into a
desired three-dimensional configuration. The frame may accommodate
placement of an unfolded or partially folded flexible circuit board
so that a fold-assisting feature, such as a hinge, incorporated
into the frame attaches to the flexible circuit board and closes
around a pivot point to gently bend the circuit board into place,
thus creating a three-dimensional folded circuit. Such a fixture
and method facilitate packaging electronic devices in a compact
form, with application to a wide range of mobile consumer
electronics, including, for example, implantable medical
devices.
Inventors: |
Primavera; Anthony A.;
(Newberg, OR) |
Assignee: |
BIOTRONIK SE & CO. KG
Berlin
DE
|
Family ID: |
46052340 |
Appl. No.: |
13/278692 |
Filed: |
October 21, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61424691 |
Dec 20, 2010 |
|
|
|
Current U.S.
Class: |
29/761 ; 53/116;
53/429 |
Current CPC
Class: |
Y10T 29/49117 20150115;
A61N 1/3758 20130101; Y10T 29/49002 20150115; H05K 2203/0169
20130101; H05K 1/028 20130101; H05K 7/16 20130101; Y10T 29/5327
20150115 |
Class at
Publication: |
29/761 ; 53/429;
53/116 |
International
Class: |
H05K 13/00 20060101
H05K013/00; B65B 63/04 20060101 B65B063/04 |
Claims
1. A fixture for use in folding a planar, flexible substrate to fit
an interior volume within a package, the fixture comprising: a
fold-assisting frame that conforms to a shape of a portion of the
interior volume within the package, such that a fold-assisting
feature of the frame may be used as an in-situ, bending jig to fold
the planar flexible substrate into a desired three-dimensional
configuration.
2. The fixture of claim 1, wherein the flexible substrate forms a
support structure for a flexible electronic circuit, and wherein
the package is an electronic device housing.
3. The fixture of claim 1, wherein the fold-assisting feature is a
hinge.
4. A fixture for folding a planar flexible circuit board to fit
into a space within an implantable medical device (IMD) housing,
the fixture comprising: a flexible, pivoting device frame that
conforms to at least a portion of a shape of the IMD housing,
wherein the pivoting device frame is used to align and bend the
flexible circuit board into a desired three-dimensional
configuration within the IMD housing.
5. A method of folding a flexible substrate, in-situ, within a
device frame, the method comprising the steps of: providing a
flexible frame of which at least a portion conforms to an interior
shape of a device housing; aligning a pivoting portion of the
flexible frame to a corresponding portion of the flexible
substrate; securing the pivoting portion to the flexible substrate
portion; and bending the pivoting portion of the flexible frame and
the flexible substrate portion together into a desired
three-dimensional configuration to fit conformally within the
housing.
6. The method of claim 5, further comprising the step of latching
the pivoting portion of the flexible frame and the substrate
portion to maintain the desired three-dimensional configuration.
Description
RELATED APPLICATION
[0001] This patent application claims the benefit of co-pending
U.S. Provisional Patent Application No. 61/424,691, filed on Dec.
20, 2010, which is hereby incorporated by reference in its
entirety.
TECHNICAL FIELD
[0002] The present disclosure concerns methods of folding or
bending flexible substrates and, in particular, concerns methods
for manufacturing electronic devices that entail folding flexible
circuit boards.
BACKGROUND
[0003] Flexible circuit boards are commonly used in compact mobile
electronic and telecommunications devices including, but not
limited to, cell phones, cameras, handheld computers, MP3 players,
global positioning system (GPS) mapping devices, implantable
medical devices, and the like, in which efficient use of space
inside a device package, or housing, is a feature of critical
importance. A typical sequence of steps for manufacturing such
mobile devices includes populating a planar flexible substrate with
electronic components by mounting components on both sides of the
substrate, folding the planar circuit into a desired
three-dimensional configuration, and then placing the
three-dimensional folded circuit inside the device package, which
may be outfitted with a supporting device frame. The planar
flexible substrate may be formed into a regular or an irregular
shape, and it may include tabs or extensions that, when folded,
conform to the interior shape of the housing or that accommodate
other parts contained within the housing, such as, for example,
batteries, telemetry units, and digital memory chips. Flexible
substrates are often made of polyimide or a similar type of polymer
that may comprise a multi-layer laminate.
[0004] A circuit folding assembly operation typically involves the
use of a complex, customized fixture, such as, for example, a
specialized jig for holding and supporting the flexible substrate
during a mechanized bending process, so as to avoid creasing the
substrate, rupturing interconnecting wires, subjecting the
substrate or components mounted thereon to high stresses during
folding, or otherwise damaging the substrate and/or components. An
exemplary multi-step bending process that relies on such equipment
is described in a published white paper by Shereen Lim from Avago
Technologies, entitled "Recommendations for Installing Flash LEDs
on Flex Circuits". Often, adhesive or mechanical fixation is
required to maintain the final, folded, three-dimensional
configuration. Customized supporting accessories such as, for
example, rigidizer plates, pallets, mandrels, clamps, and the like,
are also commonly used to assist in the bending process, as
described in U.S. Pat. No. 5,434,362 to Klosowiak, et al., entitled
"Flexible Circuit Board Assembly and Method". Such tools increase
manufacturing costs and complexity, because a new jig and
accompanying accessories must be designed and constructed for each
new folded circuit configuration. Often, operator intervention is
also necessary during folding, which may include a series of
multiple bends and/or multiple manual fixation steps. After the
bending process is complete, the folded circuit must be aligned
with the supporting frame, manually held in place so as not to
disturb the folded shape, and then carefully inserted into the
housing.
[0005] The presently disclosed invention is directed toward
overcoming one or more of the above-identified problems.
SUMMARY
[0006] Instead of folding a planar flexible substrate prior to
placing it inside a package, a novel, preferred method of
manufacturing devices built on flexible substrates employs an
in-situ, fold-assisting device frame. The fold-assisting frame
generally conforms to the shape of a portion of the interior volume
within the package, such that one or more pivoting members of the
frame itself may be used as an in-situ bending jig, in place of
conventional bending equipment, to support and fold the planar
flexible substrate into a desired three-dimensional configuration.
In an exemplary embodiment, the fold-assisting frame may
accommodate placement of an unfolded or partially folded flexible
circuit board, so that a hinge or other pivot feature incorporated
into the frame attaches to the flexible circuit board and closes
around a pivot point to gently bend the circuit board into place,
thus creating a three-dimensional folded circuit.
[0007] A method of folding a planar flexible substrate, in-situ,
within a device frame includes providing a flexible frame of which
at least a portion conforms to an interior shape of a package,
aligning a pivoting portion of the frame with a corresponding
portion of the flexible substrate, securing the flexible substrate
portion to the pivoting portion, bending the two together so as to
achieve a desired three dimensional configuration that fits
conformally within the package, and optionally latching the
pivoting portion of the flexible frame and the substrate portion in
their final positions to maintain the desired three-dimensional
configuration. Such a fixture and method facilitate packaging
electronic devices in a compact form, with application to a wide
range of mobile consumer electronics, including, but not limited
to, implantable medical devices.
[0008] Various other objects, aspects and advantages of the
presently disclosed invention can be obtained from a study of the
specification, the drawings, and the appended claims.
DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 illustrates a prior art foldable circuit for use in a
compact mobile electronic device.
[0010] FIG. 2 is a pictorial plan view of a prior art mobile
electronic device housing for an implantable medical device (IMD),
which contains the foldable circuit shown in FIG. 1.
[0011] FIG. 3 is a side elevation view of a prior art device frame
and a flexible circuit board having a pre-folded extension.
[0012] FIG. 4 is a side elevation view of the prior art device
frame of FIG. 3, into which the flexible circuit board having a
pre-folded extension shown in FIG. 3 has been mounted.
[0013] FIG. 5 is a side elevation view of a pivoting device frame
and a flexible circuit board having an elongated extension.
[0014] FIG. 6 is a side elevation view of the fold-assisting frame
shown in FIG. 5 acting as a support structure to hold the flexible
circuit board shown in FIG. 5.
[0015] FIG. 7 is a side elevation view of the fold-assisting frame
shown in FIGS. 5 and 6, supporting the flexible circuit board shown
in FIG. 4, after completion of folding.
[0016] FIG. 8 is a diagram of a passive hinge for use in the
fold-assisting frame shown in FIGS. 5-7.
[0017] FIG. 9 is a side perspective view of an active hinge for use
in the fold-assisting frame shown in FIGS. 5-7.
[0018] FIG. 10 is a top elevation view of the active hinge shown in
FIG. 9.
DETAILED DESCRIPTION
[0019] Embodiments of the present invention will be readily
understood from the following detailed description in conjunction
with the accompanying drawings. To facilitate this description,
like reference numerals designate like structural elements.
Embodiments of the invention are illustrated by way of example, and
not by way of limitation, in the figures of the accompanying
drawings.
[0020] An example of a conventional foldable "flex" circuit 90 for
use, e.g., in an implantable cardiac device is shown in FIG. 1. In
this example, the foldable flex circuit 90 generally consists of
electronic type device components 92 mounted on a flexible
substrate 94. In the example shown, foldable circuit 90 has four
sections: a fixed upper section 95; a lower section 96 designed to
bend 180-degrees as shown into a plane parallel to, and behind, the
fixed upper section 95; a lower extension 97 designed to bend away,
perpendicular to the plane of the fixed upper section 95; and an
upper extension 98 that is designed to rotate
counter-clockwise.
[0021] Referring to FIGS. 2-4, a package in the form of an
electronic device housing 100 is shown (FIG. 2) that contains a
closed, conventional internal frame 105 (FIGS. 3-4) for supporting
electronic parts, such as, for example, the foldable flex circuit
90. Conventional frame 105 may be made of an electrically
insulating material such as, for example, a polymer. Vertical
members 107 and 108 of the frame 105 serve to compartmentalize
space within the housing 100, which helps to prevent the electronic
parts from shifting away from their factory-installed positions. In
an exemplary preferred embodiment, the housing 100, into which the
conventional frame 105 is designed to fit, takes the form of an
implantable medical device (IMD) platform having a generally oval
form factor, to which an outer perimeter 110 of the frame 105
conforms. In this example, the conventional frame 105 divides
interior space within housing 100 into a left hand compartment 112,
a center compartment 114, and a right hand compartment 116,
enabling the IMD housing 100 to accommodate electronic parts of a
compact cardiac therapy device, such as, for example, a pacemaker,
implantable defibrillator, or a cardiac monitoring device, such as,
for example, an implantable loop recorder. Such cardiac therapy
devices may also accommodate, for example, a battery in the right
hand compartment 116, and a telemetry unit in the left hand
compartment 112. Connecting wires from the foldable flex circuit 90
then may be guided through a slot 117 located at an upper corner
adjoining the center and left hand compartments 114 and 112,
respectively, and then fed through an upper wall of the housing 100
to a header 118.
[0022] Referring to FIG. 3, electronic components 92 are shown
mounted to both sides of the flexible substrate 94, which is shown
partly folded. Upper extension 98 is shown at least partly pre-bent
prior to inserting flexible substrate 94 into central compartment
114 of frame 105.
[0023] Referring to FIG. 4, the foldable flex circuit 90 is shown
installed within central compartment 114 of conventional frame 105,
with the extension 98 having been pre-bent so that it may be
substantially aligned with an upper horizontal member 145 of outer
perimeter 110.
[0024] Referring to FIG. 5, a novel fixture comprising a
fold-assisting frame 205 is shown that accommodates the foldable
flex circuit 90 without requiring a pre-bending operation.
Designing and manufacturing one or more fold-assisting features as
part of the frame 205 may be accomplished for a substantially
similar cost as is currently incurred in designing and
manufacturing the conventional frame 105. In addition, the novel
fixture serves to eliminate equipment, accessories, fixation, and
operator intervention associated with the pre-bending operation.
More specifically, the fold-assisting frame 205 may take the form
of a flexible, pivoting device frame such that in an exemplary
embodiment, outer perimeter 110 of fold-assisting internal device
frame 205 has, in place of the horizontal member 145 (see FIG. 4),
a pivoting member 210 that pivots around a rotational axis 215,
located at a pivot point 220. As one example of a fold-assisting
feature, pivoting member 210 may be molded, recessed, or otherwise
shaped to conform to contours of extension 98.
[0025] Thus, as shown in FIG. 6, foldable flex circuit 90 may be
placed into central compartment 114 so that upper extension 98 is
in its upright position. Upper extension 98 may then be secured to
pivoting member 210 by a retaining feature 230 in the form of, for
example, a clip, a finger, or an edge clamp, that attaches to
extension 98 without obstructing connections to components 92
mounted thereon.
[0026] As pivoting member 210 is rotated 90-degrees
counter-clockwise (as shown) around pivot point 220, extension 98
is thus folded into a desired three-dimensional configuration, as
shown in FIG. 7. Upon completion of the folding step, a latching
mechanism 240 may be provided to maintain the pivoting member 210
in its closed position. In the example shown, the final folded
circuit configuration of extension 98 is such that connecting wires
may emerge from the top surface of extension 98 to provide access
for external connections to be made within header 118. In the case
of an IMD, such external connections are made by feeding leads
through openings in header 118 to mate with connecting wires on the
top surface of extension 98.
[0027] In alternative embodiments, electronic parts may be
associated with a different type of IMD, such as, for example, a
neurostimulator, a different type of mobile electronic device, such
as, for example, a mobile computing or telecommunications device,
or even a non-electronic device, as long as all or a subset of
device components 92 reside on a flexible substrate 94 that folds
to fit within a package. A package, like housing 100, may therefore
contain, in place of foldable flex circuit 90, an alternative
arrangement of electronic, mechanical or micro-mechanical,
chemical, or biological parts, or combinations thereof, mounted or
otherwise attached to flexible substrate 94, and supported by a
fixture comprising fold-assisting frame 205.
[0028] With reference to FIGS. 8-10, shown are two alternative
embodiments of a hinge that may be adapted for use in the
fold-assisting device frame 205, and include a passive hinge 300
(FIG. 8) and an active hinge 310 (FIGS. 9 and 10), among other
possible exemplary embodiments. Passive hinge 300 or active hinge
310 is preferably located at pivot point 220. Passive hinge 300 is
embodied by a simple flexor 315 that facilitates bending the
pivoting member 210. In FIG. 9, a side view of active hinge 310
shows how a first hinge flange 320 having a pivot post 330 may be
joined to a second hinge flange 340 having a hollow cylinder 350.
Pivot post 330 and hollow cylinder 350 are aligned along rotational
axis 215, so that pivot post 330 may be inserted into hollow
cylinder 350, enabling the first flange 320 to rotate about axis
215 with respect to the second flange 340, which remains in a
substantially fixed position. FIG. 10 shows a top plan view of
active hinge 310 thus assembled.
[0029] Although certain embodiments have been illustrated and
described herein, it will be appreciated by those of ordinary skill
in the art that a wide variety of alternative or equivalent
embodiments or implementations, calculated to achieve the same
purposes, may be substituted for the embodiments illustrated and
described herein without departing from the scope of the present
invention. Those of skill in the art will readily appreciate that
embodiments in accordance with the present invention may be
implemented in a very wide variety of ways. This application is
intended to cover any and all adaptations and/or variations of the
embodiments discussed herein.
[0030] The terms and expressions which have been employed in the
foregoing specification are used therein as terms of description
and not of limitation, and there is no intention, in the use of
such terms and expressions, to exclude equivalents of the features
shown and/or described or portions thereof, it being recognized
that the scope of the invention is defined and limited only by the
claims that follow.
[0031] It will be apparent to those skilled in the art that
numerous modifications and variations of the described examples and
embodiments are possible in light of the above teachings of the
disclosure. The disclosed examples and embodiments are presented
for purposes of illustration only. Other alternate embodiments may
include some or all of the features disclosed herein. Therefore, it
is the intent to cover all such modifications and alternate
embodiments as may come within the true scope of this invention,
which is to be given the full breadth thereof. Additionally, the
disclosure of a range of values is a disclosure of every numerical
value within that range.
* * * * *