U.S. patent application number 14/985503 was filed with the patent office on 2017-07-06 for connecting mid-board electronic devices.
The applicant listed for this patent is International Business Machines Corporation. Invention is credited to Tymon BARWICZ, Jerome BOUGIE, Paul Francis FORTIER, Alexander JANTA-POLCZYNSKI, Stephan L. MARTEL.
Application Number | 20170196097 14/985503 |
Document ID | / |
Family ID | 59227153 |
Filed Date | 2017-07-06 |
United States Patent
Application |
20170196097 |
Kind Code |
A1 |
BARWICZ; Tymon ; et
al. |
July 6, 2017 |
CONNECTING MID-BOARD ELECTRONIC DEVICES
Abstract
A micro-electronic cover has a planar portion sized and
dimensioned to be positionable over and cover electronic components
that are electrically connected on a board. The cover has a
peripheral edge surrounding the planar portion and the electronic
components. The peripheral edge connects the planar portion with
the board to define a cover interior. The peripheral edge includes
a side opening which provides access for passage of a connector
part from a exterior to the cover to a position within the cover
interior.
Inventors: |
BARWICZ; Tymon; (Yorktown
Heights, NY) ; BOUGIE; Jerome; (Bromont, CA) ;
FORTIER; Paul Francis; (Richelieu, CA) ;
JANTA-POLCZYNSKI; Alexander; (Shefford, CA) ; MARTEL;
Stephan L.; (Bromont, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
International Business Machines Corporation |
Armonk |
NY |
US |
|
|
Family ID: |
59227153 |
Appl. No.: |
14/985503 |
Filed: |
December 31, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/4853 20130101;
G02B 6/3893 20130101; G02B 6/426 20130101; H05K 7/2039 20130101;
G02B 6/30 20130101; H05K 5/0004 20130101; G02B 6/428 20130101; G02B
6/4292 20130101; G02B 6/3887 20130101 |
International
Class: |
H05K 5/00 20060101
H05K005/00; G02B 6/38 20060101 G02B006/38; G02B 6/42 20060101
G02B006/42; G02B 6/30 20060101 G02B006/30; H05K 7/20 20060101
H05K007/20; H01L 21/48 20060101 H01L021/48 |
Claims
1. A micro-electronic cover for a board having electrically
connected electronic components which can include photonic
components, comprising: a planar portion sized and dimensioned to
be positionable over and cover the electronic components on the
board; a peripheral edge surrounding the planar portion and the
electronic components, the peripheral edge connecting the planar
portion with the board to define a cover interior, the peripheral
edge including a side opening providing access for passage of a
connector element from a position exterior to the cover interior to
a position within the cover interior; and a brace connected to the
planar portion and positioned proximate the side opening and
extending away from the peripheral edge.
2. The micro-electronic cover of claim 1, wherein the cover is
thermally conductive, and contacts at least one heat generating
electronic component on the board to conduct heat away from the at
least one heat generating electronic component.
3. The micro-electronic cover of claim 1, wherein the heat
generating electronic component is a photonic device, and the
connector element is a ferrule connected to the photonic device to
transmit light to the photonic device.
4. The micro-electronic cover of claim 1, wherein the brace is
shaped to engage and support a clip, the clip shaped to engage the
connector element.
5. The micro-electronic cover of claim 1, wherein the clip is
shaped to hold together two mating portions of a connector.
6. The micro-electronic cover of claim 4, wherein the connector
element is a fiber optic ferrule.
7. The micro-electronic cover of claim 4, wherein the brace
includes one or more apertures for admitting passage of excessive
adhesive through the brace.
8. The micro-electronic cover of claim 1, wherein the cover is
fabricated from metal.
9. The micro-electronic cover of claim 1, wherein the cover is
stamped, formed, coined, or milled.
10. The micro-electronic cover of claim 1, wherein the cover is
fabricated from a heat conducting polymer having a conductivity
value of at least 50 W/mK.
11. A photonic module compatible with surface mounting on a printed
circuit board, the photonic module comprising: a laminate with
electrical connections on each of two opposing sides with
electrical routing between the electrical connections; a photonic
die flip-chip mounted on the laminate and electrically connected to
the electrical connections on one of the two opposing sides of the
laminate; a first fiber optic ferrule mating portion optically
connected to the photonic die through an optical link; a
micro-electronic cover comprising: a planar portion sized and
dimensioned to be positionable over and cover the laminate; and a
peripheral edge surrounding the planar portion and the laminate,
the peripheral edge connecting the planar portion with a circuit
board to define a cover interior, the peripheral edge including a
side opening providing access for passage of a connector element
from a position exterior to the cover interior to a position within
the cover interior. a brace connected to the planar portion and
positioned proximate the side opening and extending away from the
peripheral edge; and a clip affixed to the first fiber optic
ferrule portion and the cover, the clip sized and dimensioned to
secure a mating connection between the first fiber optic ferrule
portion and a second fiber optic ferrule portion including a fiber
optic cable when a second fiber optic ferrule portion is mated to
the first fiber optic ferrule portion.
12. The device of claim 11, where the laminate includes a cutout
portion exposing an optical connection to the photonic die.
13. The device of claim 11, where one of the two opposing sides of
the laminate is an underside, and the electrical connections on the
underside are a ball grid array.
14. The device of claim 11, where the photonic die includes
self-alignment grooves for aligning a connection of the optical
link to the ferrule.
15. The device of claim 11, where the photonic die includes
self-alignment grooves for aligning a connection of the optical
link from the ferrule to the photonic die.
16. The micro-electronic cover of claim 11, wherein the brace is
adhered to the clip and the clip is adhered to the first fiber
optic ferrule mating portion.
17. The micro-electronic cover of claim 16, wherein the clip
includes a plate, and a portion of the plate that is adhered to the
brace includes one or more apertures to admit passage of adhesive
through the plate into contact with the first fiber optic ferrule
mating portion, the brace, clip, and connector element being
thereby mutually adhered.
18. The micro-electronic cover of claim 11, the brace formed by
bends and including extending faces positioned to lie proximate a
surface of the clip, at least one bend positioning a clip engaging
portion of the brace at an overlying orientation with respect to
the clip.
19. A method of securing a connector portion to a photonic device,
comprising: connecting a photonic die to a laminate; attaching a
clip to a connector portion; attaching the clip and connector
portion to the photonic die; and securing a micro-electronic cover
to the clip and photonic die, the cover including a planar portion
sized and dimensioned to be positionable over and cover the
photonic die, the cover including a peripheral edge surrounding the
planar portion and the photonic die, the peripheral edge connecting
the planar portion with an underlying circuit board to define a
cover interior, the peripheral edge forming a gap through which a
connection can be made between the photonic die and the connector
portion.
20. The method of claim 19, further including thermally connecting
the photonic die to the micro-electronic cover.
Description
FIELD OF THE DISCLOSURE
[0001] The present disclosure generally relates to connecting
mid-board electronic devices, and more particularly to a
micro-electronic cover which provides access and strain relief.
BACKGROUND OF THE DISCLOSURE
[0002] Mid board optical modules (MBOs) enable moving optical I/O
connections from a system faceplate directly onto a printed circuit
board (PCB), enabling higher throughput.
[0003] US CONEC of North Carolina, USA, manufactures "durable,
composite, Polyphenylene Sulfide (PPS) based thermoplastic ferrules
available with up to 72 fiber holes that terminate 125 micrometer
optical fiber. The alignment mechanism consists of two stainless
steel guide pins that fit into precisely molded alignment holes.
The ferrules are used in conjunction with US Conec's industry
hailed, MTP.RTM. brand, MPO type connectors; however, they are also
suitable for custom designed passive or active fiber coupling
packages. Fiber is secured to the ferrules with an optical
connector grade thermal cure epoxy and can be polished with a
variety of commercially available batch connector polishing
machines."
[0004] US CONEC additionally manufactures connector housings that
provide quick connection for up to 72 optical fibers. Connection
integrity is provided by adapter latches which are locked into
place on the connector plug by a spring loaded sliding and locking
mechanism. Precision alignment is achieved with guide pins combined
with the tightly controlled guide pin holes on MT ferrules.
Removable housings allow for quick change of gender, interferometry
or connector re-polishing. US Conec's MTP brand connector
components are fully compliant with IEC Standard 61754-7 and TIA
604-5-Type MPO." If the connector is latched to the adapter, the
ferrule endface may be cleaned through the opposite side of the
adapter. A connector not attached to an adapter may also be easily
cleaned with the housing in place. (see
http://www.usconec.com).
[0005] A thermal heat sink can have the form of a cover which
protects underlying electronic components, and which captures the
heat generated by an electronic component to control the
temperature of the component. The transferred heat is passed from
the heat sink to a coolant or air in motion, cooling the electronic
device to which the heat sink is attached. Thermal adhesive or
thermal grease helps to fill air gaps between the heat sink and the
electronic device. The most common heat sink materials are aluminum
or copper alloys.
SUMMARY OF THE DISCLOSURE
[0006] In an embodiment of the disclosure, a micro-electronic cover
for a board having electrically connected electronic components
which can include photonic components, comprises a planar portion
sized and dimensioned to be positionable over and cover the
electronic components on the board; a peripheral edge surrounding
the planar portion and the electronic components, the peripheral
edge connecting the planar portion with the board to define a cover
interior, the peripheral edge including a side opening providing
access for passage of a connector element from a position exterior
to the cover interior to a position within the cover interior; and
a brace connected to the planar portion and positioned proximate
the side opening and extending away from the peripheral edge.
[0007] In another embodiment of the disclosure, a photonic module
compatible with surface mounting on a printed circuit board
comprises a laminate with electrical connections on each of two
opposing sides with electrical routing between the electrical
connections; a photonic die flip-chip mounted on the laminate and
electrically connected to the electrical connections on one of the
two opposing sides of the laminate; a first fiber optic ferrule
mating portion optically connected to the photonic die through an
optical link; a micro-electronic cover comprising: a planar portion
sized and dimensioned to be positionable over and cover the
laminate; and a peripheral edge surrounding the planar portion and
the laminate, the peripheral edge connecting the planar portion
with a circuit board to define a cover interior, the peripheral
edge including a side opening providing access for passage of a
connector element from a position exterior to the cover interior to
a position within the cover interior; a brace connected to the
planar portion and positioned proximate the side opening and
extending away from the peripheral edge; and a clip affixed to the
first fiber optic ferrule portion and the cover, the clip sized and
dimensioned to secure a mating connection between the first fiber
optic ferrule portion and a second fiber optic ferrule portion
including a fiber optic cable when a second fiber optic ferrule
portion is mated to the first fiber optic ferrule portion.
[0008] In a further embodiment of the disclosure, a method of
securing a connector portion to a photonic device, comprises
connecting a photonic die to a laminate; attaching a clip to a
connector portion; attaching the clip and connector portion to the
photonic die; and securing a micro-electronic cover to the clip and
photonic die, the cover including a planar portion sized and
dimensioned to be positionable over and cover the photonic die, the
cover including a peripheral edge surrounding the planar portion
and the photonic die, the peripheral edge connecting the planar
portion with an underlying circuit board to define a cover
interior, the peripheral edge forming a gap through which a
connection can be made between the photonic die and the connector
portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Reference may be had to the accompanying figures where like
reference numerals refer to identical or functionally similar
elements throughout the separate views, and which together with the
detailed description below are incorporated in and form part of the
specification, serve to further illustrate various embodiments and
to explain various principles and advantages all in accordance with
the present disclosure, in which:
[0010] FIG. 1 depicts a prior art cover;
[0011] FIG. 2 depicts an assembly including cover of the disclosure
including a clip extension for retaining a clip;
[0012] FIG. 3 depicts an exploded view of the assembly of FIG.
2;
[0013] FIG. 4 depicts a top perspective view of the cover of FIG.
2;
[0014] FIG. 5 depicts a bottom perspective view of the cover of
FIG. 2;
[0015] FIG. 6 depicts a cross-section view of the assembly of FIG.
2 taken through line A-A;
[0016] FIG. 7 depicts a cross-section view of the assembly of FIG.
2 taken through line B-B;
[0017] FIG. 8 depicts an alternative form of a cover of the
disclosure and adhesive connections, relative to the cross-section
taken through line B-B;
[0018] FIG. 9 depicts another alternative form of a cover of the
disclosure and adhesive connections, relative to the cross-section
taken through line B-B;
[0019] FIG. 10 depicts a cross-section view of the assembly of FIG.
2 taken through line C-C;
[0020] FIG. 11 depicts a perspective view of an alternative board
and connector configuration of the disclosure;
[0021] FIG. 12 depicts a perspective view of an assembly and
alternative cover of the disclosure;
[0022] FIG. 13 depicts a top perspective view of the cover of FIG.
12; and
[0023] FIG. 14 depicts a bottom perspective view of the cover of
FIG. 12.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0024] As required, detailed embodiments are disclosed herein;
however, it is to be understood that the disclosed embodiments are
merely examples and that the systems and methods described below
can be embodied in various forms. Therefore, specific structural
and functional details disclosed herein are not to be interpreted
as limiting, but merely as a basis for the claims and as a
representative basis for teaching one skilled in the art to
variously employ the present subject matter in virtually any
appropriately detailed structure and function. Further, the terms
and phrases used herein are not intended to be limiting, but
rather, to provide an understandable description of the
concepts.
[0025] The terms "a" or "an", as used herein, are defined as one or
more than one. The term plurality, as used herein, is defined as
two or more than two. The term another, as used herein, is defined
as at least a second or more. The terms "including" and "having,"
as used herein, are defined as comprising (i.e., open language).
The term "coupled," as used herein, is defined as "connected,"
although not necessarily directly, and not necessarily
mechanically.
[0026] With reference to the figures, the disclosure provides a
novel connection for securing connections to a printed circuit
board (PCB), and particularly for the assembly of microelectronic,
optoelectronic and photonic components. A connection system 100 of
the disclosure provides for securing and preventing separation of a
connection between two or more components, for example mating
ferrule halves, as well as providing strain relief and resistance
to out of plane misalignment. System 100 can further be provided
with a maximum vertical dimension "V" that is not substantially
greater than a vertical dimension of the components that system 100
is securing.
[0027] With reference to FIG. 1, an example of a prior art
microelectronic coverplate, lid, or cover 600 is shown, and which
is typically formed of metal or other heat conducting material. As
such, cover 600 serves as a heat sink, to absorb heat generated by
the underlying electronic components, and to spread the heat over
the surface area of the cover 600, where it may be dissipated into
the environment to help prevent overheating of the underlying
components. In addition, cover 600 provides for mechanical
protection of the underlying components, and can contribute to
achieving a device coplanarity specification required for further
assembly steps.
[0028] With reference to FIGS. 2-5, a cover sidewall 402 joins to
planar portion 404 to form a protected interior space for
containing electronic components, including photonic device 512.
Cover 400 includes a mechanical stabilization component which can
be combined with a material of high thermal conductivity. More
particularly, cover 400 can be formed of metal or another material,
advantageously having a high thermal conductivity where heat
dissipation is required. Examples include aluminum alloys, such as
aluminum alloy 1050A, 6061, and 6063; copper or a copper alloy,
such as copper-tungsten or a copper-silver alloy matrix; a silicon
carbide in an aluminum matrix; and beryllium oxide in beryllium
matrix. In embodiments, cover 400 is molded over the underlying
components, or includes a moldable material, to encapsulate and
further protect the underlying device. Sidewall 402 can be formed
of a different material than planar portion 404.
[0029] In FIGS. 2-3, a system 100 of the disclosure is illustrated,
in which a microelectronic coverplate, lid, or cover 400 of the
disclosure is positioned over a photonic device 512 and any
associated components, and also covers a portion of board 502.
While a photonic device 512 and laminate 502 are shown and
described as an example, for ease of understanding, it should be
understood that cover 400 can be used together with any electronic
or photonic device, and any type of substrate, including a laminate
or circuit board of any type.
[0030] Electrical connections between underlying devices, such as
photonic die 512 and laminate 502, can be formed for example with a
flip-chip interface 514, whereby photonic device 512 is
electrically connected on its device side, which is facing downward
in the depiction, and can therefore be covered over its top and all
sides by cover 400. In addition, electrical connection on the
underside of laminate 502 can further route the electrical signals
to a printed circuit board. The electrical connections between a
laminate and a printed circuit board can employ a ball grid array
(BGA) or a land grid array (LGA) as known to those of skill in the
art. In other embodiments, cover 400 can extend beyond electrical
bonds extending laterally to heat producing components. In further
embodiments, cover 400 does not cover the sides of the heat
generating components, and contacts such components only on a top
surface of the components. In accordance with the disclosure, as
described further herein, cover 400 covers some components, and
exposes elements to enable an electrical or optical connection.
[0031] While an MT style or other style ferrule 530/536 is
described herein, the system 100 of the disclosure can be used to
stabilize and secure a wide variety of electrical or optical
ferrules which are currently known or are hereinafter developed, as
will be explained further elsewhere herein. While the disclosure
illustrates mating optical ferrules, system 100 can be used to
secure connections relying on electron flow in a similar
manner.
[0032] With further reference to FIGS. 2-3, an MT style ferrule
termination is illustrated, which includes mating halves 530/536
which are mutually connectable to enable transmission of a light
encoded signal therethrough. The ferrule halves 530 and 536 include
light guiding structures which are not detailed herein, but which
are well known, and which transfer light from a fiber optic cable
540 (FIG. 2) to light guiding structures in the chip device. Other
styles of ferrules exist or are to be developed which can also be
used in accordance with the disclosure, as will be understood in
view of the disclosure.
[0033] In many applications of board 502, it is desired to place
boards in close overlying conformity to one another, or to
otherwise install board 502 in a location where vertical clearance
is extremely limited. The disclosure provides for forming and
securing a connection between mating connector portions, without
increasing a height of the connection, and without requiring a
housing/jacket for the connection.
[0034] All of the cover 400 and underlying devices can be assembled
together during manufacturing processing using any high throughput
automated standard pick and place tool such as are used in the
microelectronic industry, referred to hereinafter as a pick and
place system.
[0035] Clip 110 provides resistance to unintended disconnection,
pullout, or separation of ferrules 530, 536. However, clip 110
should be considered illustrative, and other forms of clips can be
used in accordance with the disclosure. Clip 110 engages two mating
connector portions using one or more arms 116, in the example
illustration the mating connector portions are fixed ferrule 530
and cable-side ferrule 536, and urges them together in mating
conformity. A base plate 124 of clip 110 attaches to a connector
portion, in this example fixed ferrule 530, and arms 116 are
attached to and extend from plate 124.
[0036] The attachment of clip 110 to board 502 is advantageously
sufficiently strong to withstand the pulling force required to
install and ensure a secure connection of clip 110 onto cable
ferrule 536. The connection between fixed ferrule 530 and the
photonic device can be fragile, for example it can include a glued
interface connection which should not be unduly stressed. This is
true for many types of connectors.
[0037] To transfer pullout forces to more durable components, cover
400 functions as strain relief. As can additionally be seen in
FIGS. 2-5, cover 400 is formed with an overhanging support clip
support 412 which extends from planar portion 404, and forms a side
opening 434. In an embodiment, clip support 412 is formed
integrally with cover 400, reducing part count and assembly steps,
and increasing reliability. However, clip support 412 can be
separately attached to cover 400 by any means, including soldering,
brazing, adhesive, or fasteners. In the embodiment of FIGS. 16-19,
it may be seen that cover 400 can be formed by stamping, including
for example progressive stamping from a continuous feed supply of
sheet material. A peripheral outline of cover 400, as well as
notches 422, can be cut before, during, or after the stamping
process. Cover 400 can also be formed by bending, for example. Side
opening 434 enables passage of connections or components from under
cover 400 to an exterior of cover 400.
[0038] Clip support 412 can be sized and shaped to enable a
structural link for connection to plate 124 or any other portion of
clip 110, and forms a supporting surface for clip 110. Additional
support can be provided by including one or more side tabs or faces
414 which extend downwards to overlie clip side walls, thereby
increasing an overlap area with clip 110 and fixed ferrule 530.
Dimensions of clip support 412 and faces 414 correspond to
component and assembly tolerance for a particular application.
Adhesive 424 can be interposed between clip support 412 and clip
110. Adhesive 424 can fill and flow through apertures 114 within
clip plate 124 to contact fixed ferrule 530, creating a rigid bond
between and among fixed ferrule 530, clip 110, and cover 400,
completing a structural link among them.
[0039] Cover 400 is in contact with at least one photonic device
512, and attached laminate board 502, at a board end 416, and is
also attached to and overlying clip 110 and fixed ferrule 530 at
lid end 418. Cover 400 thereby acts as a strain relief for forces
imparted to clip 110 and ferrule portions 530 and 536, protecting
the sensitive connecting area on photonic device 512, including the
optical link 508. Such forces can increase, for example, when cable
ferrule 536 is connected to fixed ferrule 530, and when clip 110 is
connected to cable ferrule 536. Strain can additionally be imparted
to clip 110 and ferrule portions 530, 536 when a cable connected to
cable ferrule 536 is pulled. If not for strain relief as described
herein, such forces could be imparted to optical link 508 or to
associated optical fibers or a polymer ribbon, which can be
particularly fragile. Cover 400 can be efficiently positioned upon,
and fastened to, board 502, photonic device 512, and clip 110 using
a pick and place system, during the manufacture of system 100.
[0040] A bend offset 420 can be stamped or otherwise formed in
cover 400 to position clip support 412 in overlying proximity to
plate 124 or other portion of clip 110, including for example arms
116A, 116B. In an embodiment, offset 420 is only as deep as needed,
if at all, to carry out this overlying configuration, in order to
maintain an overall height profile of system 100 as small as
possible, while still able to accommodate the dimensions of an
optical component, such as fixed ferrule 530, within a final module
assembly of system 100. For example, plate 400 can add only the
thickness of the material of clip support 412, plus the thickness
of adhesive layer 424 interposed between clip 110 and clip support
412, if applied. Similarly, notches 422 cooperate to ease bend 420
and the removal of side surfaces of cover 400 to create an opening
through which optical link 508 can pass, along with some or all of
fixed ferrule 530 or other connector part, if a connector part is
to be positioned partly or wholly within board 502 and under cover
400. In one embodiment a cut-out in board 502 can be employed to
provide clearance for ferrule 530.
[0041] FIG. 6 is a cross-section taken along line A-A of FIG. 2,
illustrating a location of a layer of adhesive 424 operative to
connect cover 400 to clip 110. The adhesive can be any material
known in the art which can securely bond cover 400 and clip 110 and
fixed ferrule 530 or other connector portion. It is advantageous
for all components, including the adhesive, to have similar thermal
expansion properties, to reduce the possibility of adhesive failure
due to stress imposed by differential expansion, particularly as
temperature or humidity changes can be significant for the photonic
device 512, and other components on board 502 which may be cooled
by cover 400. Adhesives described herein are further selected to
provide a desired extent of rigidity/flexibility to best protect
components from shock and differential thermal expansion, while
reliably securing the adhered parts relative to each other, as
described. Other methods of attaching cover 400 to fixed ferrule
530 through clip 110 can be used, including soldering or brazing,
crimping, or using fasteners.
[0042] FIG. 7 is a cross-section taken along line B-B of FIG. 2,
illustrating the placement of adhesive 424. Additionally, adhesive
426 may flow from 424 or be placed between sidewalls 126 of clip
110 and side walls of fixed ferrule 530, and can further engage
other structures associated with clip 110 and fixed ferrule 530.
Clip apertures 114 further help to create links between fixed
ferrule 530 and cover plate 400. Apertures 114 can additionally
direct adhesive to flow away from the front, or optical face 546,
of fixed ferrule 530.
[0043] FIG. 8 illustrates an alternative placement of adhesive,
including adhesive 428 which is positioned similarly to brace
adhesive 424, but clip support 412 is formed to be wider, producing
a space between side faces 414 and sidewalls 126 of clip 110, which
is filled with adhesive 428. In a further alternative placement of
adhesive, shown in FIG. 9, adhesive 430 is placed between plate 124
of clip 110, as well as between sidewalls 126 of clip 110 and fixed
ferrule 530. While adhesives 424/426 and 428/426 are illustrated
separately for clarity, during production, a single application of
adhesive can be caused to flow through apertures 114 (FIG. 9) of
clip 110 to lie at the locations indicated by 424, 428, and
426.
[0044] As can further be seen in FIG. 9, apertures 114 in plate 124
allow adhesive to flow through plate 124, to link cover clip
support 412 and fixed ferrule 530 through plate 124. Accordingly
adhesive can flow from clip support 412 to fixed ferrule 530. In an
embodiment, clip support 412 is provided with one or more channels
or apertures 442 (FIG. 9) along faces 414, for enabling and guiding
a flow of excess adhesive, to protect fixed ferrule 530 optical
face 546. Excessive adhesive can therefore flow from a space
between fixed ferrule 530 and clip 110 to a space between clip 110
and an interior side of clip support 412 and be redirected by cover
apertures 442 or inner grooves to limit the overflow from moving in
a direction of the optical face.
[0045] FIGS. 7-9 further illustrate embedded optical links 568
within fixed ferrule 530, as well as apertures 556, which mate with
corresponding alignment pins (not shown) of a mating ferrule
half.
[0046] FIG. 10 is a cross-section taken along line C-C of FIG. 2,
illustrating a location of adhesive 432 along a periphery of cover
400, which secures cover 400 to board 502, thereby completing a
connection from fixed ferrule 530 through adhesive 426 or 430 to
clip 110, through adhesive 424 or 428 to clip support 412, and
finally through adhesive 432 to board 502, securely bonding fixed
ferrule 530 to board 502.
[0047] As further illustrated in FIG. 10, adhesive 436 can be
applied in other locations where cover 400 is advantageously
secured to a component or to board 502. Adhesive 432 and 436 can
further be selected to include a material which readily transfers
heat from a heat generating component into cover 400 for
dissipation. Similarly, thermal adhesive or thermal grease 440 is
provided between photonic device 512 and cover 400, and other
devices can used thermal or structural adhesive in connection with
cover 400, to meet performance objectives or other
specification.
[0048] While illustrated in cross-section, it should be understood
that adhesive 424, 426, 428, and 430, 432, 436, and 440 can be
similar or different to each other, and can extend completely
throughout overlapping portions of the components adhered together,
or only along portions of overlapping components, as determined by
the requisite adhesion strength, thermal transfer requirements,
cost considerations, and difficulty of applying the adhesive or
thermal transfer material. An additional consideration is the
potential for adhesive to flow before curing, to flow away from a
location of application as parts are pressed into place, or to flow
with the application of heat or heat ramp, whereby the adhesive
could interfere with operation of the circuit or fiber optic
connection or clip 110. Accordingly, sufficient space is provided
in consideration of such anticipated flow. Additionally, adhesive
can be applied to only one side, or two or more sides of an
object.
[0049] As shown in FIG. 11, an opening, recess or cutout 570 can be
provided in laminate 502, sized to accommodate displacement of
fixed ferrule 530 entirely under cover 400, where it may be adhered
to cover 400 and/or clip support 412. Cutout 570 may be required if
the optical links are thicker than the electrical links between the
photonic side and the laminate, and/or for assembly flow
requirements, as described in U.S. Patent Publications 2014/0177222
and 2014/0179034. Positioned in this manner, cable-side ferrule 536
can be passed through side opening 434 of cover 400 to connect with
fixed ferrule 530. Alternatively, rather than forming a cutout 570,
fixed ferrule can be positioned on top of laminate 502, and cover
400 and clip support 412 can provide sufficient clearance to
accommodate a dimension of fixed ferrule 530. It should also be
noted that while cover 400 is shown adhered to laminate 502 in FIG.
10, cover 400 can alternatively be supported on posts, blocks, or
other structures, depending on the components upon laminate 502 or
other packaging requirements. Whether positioned within cutout 570,
or positioned above laminate 502, fixed ferrule 530 can be adhered
or otherwise bonded directly to laminate 502.
[0050] In an embodiment, cover 400 and clip 110 can be stamped from
a single plate or unitary part of monolithic or composite material.
In such a configuration, adhesive 424 may not be needed. However, a
typical assembly flow includes connecting the photonic chip or die
516 to board 402, attaching clip 110 to fixed ferrule 530,
attaching the clip/ferrule assembly to die 516, and securing cover
400 to die 516 or a photonic device connected to die 516, and to
clip 110 and fixed ferrule 530. An alternate assembly flow includes
connecting the photonic chip or die 516 to board 402, attaching the
ferrule to die 516, attaching clip 110 to fixed ferrule 530, and
attaching secure cover 400 to die 516 or a photonic device
connected to die 516, and to clip 110 and fixed ferrule 530.
[0051] In an embodiment, cover 400 is directly attached to fixed
ferrule 530 at the same time as when clip 110 is attached to fixed
ferrule 530. Therefore, this assembly of 400/110/530 is connected
to die 516 together.
[0052] Adhesive can be applied to components, including but not
limited to board 502, photonic device 512, cover 400, clip support
412, side faces 414, clip 110, and fixed ferrule 530, prior to
positioning by pick and place, or after placement. In an
embodiment, clip support 412 can be sized and shaped to enable
securely gripping clip 110, as shown in FIG. 7, until adhesive
cures or adhesive can be applied. Clip support 412 or side faces
414 can further be provided with mating extensions (not shown)
which engage indented or shaped portions of clip 110 for this
purpose.
[0053] With reference to FIGS. 12-14, an alternative cover 400A
functions as shown and described with respect to cover 400, and is
manufactured using a milling or molding process. Cover 400A can be
formed of metal as described with respect to cover 400, and can be
CNC milled from metal. Alternatively, cover 400A can be molded from
thermally conductive plastic, which can be lighter than aluminum or
other metals, and have reasonable conductivity values for the
application requirements, for example a conductivity value of
50-500 W/mK, or higher. Thermally conductive plastics can include,
for example, a base of crystalline or amorphous resin, or a
polysulfone compound, with an additive of graphite carbon fiber
(for RFI shielding) or ceramic (for electrical insulation),
including for example aluminum nitride and boron nitride, or any
other material. Whether metal or thermally conductive plastic,
cover 400A can be attached or mold to board 502, photonic device
512 or other components, and clip 110, as described with respect to
cover 400.
[0054] The disclosure provides a cover 400 which, together with
ferrule portions 530, 536, clip 110, and other components of the
disclosure produce a packaging solution for connecting fiber optic
cables, or other data cable, to a processing board, with a minimal
vertical profile.
[0055] The disclosure enables an optimal location of the ferrule
portions 530, 536 on the module edge to enable data transfer
through the ferrule, and for enabling cooling of this and similar
higher performance devices. The control of a smaller vertical
height is enabled by positioning a connector at a board edge, using
access provided by a side opening 434 in cover 400. The disclosure
enables positioning of ferrule optical connection portions 530, 536
at the periphery of the photonic module, while protecting the
fragile fiber connection extending from fixed ferrule 530 to
photonic device 512.
[0056] The disclosure further avoids a requirement for excessively
large fiber optic connector housings which cannot be used with
dense board 502 packaging, and which can further introduce problems
of tolerance stackup, cost, and assembly complexity. Additionally,
prior art housings and latches cannot be easily assembled to board
502, photonics device 512, and/or cover 400 during a pick and place
manufacturing process, particularly due to tight tolerances
commonly required for high density applications. Alternatively, the
disclosure provides a device and method which is capable of
providing a low profile releasable fiber optic connector which can
be assembled using a pick and place system.
[0057] Accordingly, the disclosure enables forming and maintaining
a secure connection between mating ferrule components while
enabling a vertical profile that is not taller than the ferrule
connection. A system 100 of the disclosure can be assembled using
standard high-throughput pick and place equipment, reducing a
requirement for manual assembly.
[0058] System 100 can be used to secure a connection of simplex,
duplex, and ribbon ferrules, the ferrules fabricated with any
material, for example stainless steel, a polymeric material, a
composite material, or a ceramic material. For example, clip 110
can be shaped to extend laterally around, and to contact a trailing
end shoulder of an MT, LC, SC, or MU ferrule of any known or
hereinafter developed size. Clip 110 provides ready access to a
face of fixed ferrule 530 for cleaning or inspection. In an
embodiment, plate 124, as shown, does not obscure or cover the face
of fixed ferrule 530 from access from above clip 110.
[0059] The description of the present disclosure has been presented
for purposes of illustration and description, but is not intended
to be exhaustive or limited to the disclosure in the form
disclosed. Many modifications and variations will be apparent to
those of ordinary skill in the art without departing from the scope
and spirit of the disclosure. The embodiment was chosen and
described in order to best explain the principles of the disclosure
and the practical application, and to enable others of ordinary
skill in the art to understand the disclosure for various
embodiments with various modifications as are suited to the
particular use contemplated.
* * * * *
References