U.S. patent application number 16/869985 was filed with the patent office on 2021-07-08 for method for bonding plastic component to printed circuit board.
The applicant listed for this patent is FORWARD OPTICS CO., LTD.. Invention is credited to JUEI-PIN CHEN, WEI SHEN, HUAI-AN WU.
Application Number | 20210212215 16/869985 |
Document ID | / |
Family ID | 1000005666540 |
Filed Date | 2021-07-08 |
United States Patent
Application |
20210212215 |
Kind Code |
A1 |
CHEN; JUEI-PIN ; et
al. |
July 8, 2021 |
METHOD FOR BONDING PLASTIC COMPONENT TO PRINTED CIRCUIT BOARD
Abstract
A method for bonding aplastic component to a printed circuit
board includes the steps of: a) providing the plastic component,
the printed circuit board, and at least one positioning member, b)
disposing at least one welding layer, c) positioning the plastic
component and the printed circuit board relative to each other, d)
melting the at least one welding layer while the plastic component
is maintained in a positioning position, and e) cooling the at
least one welding layer while the plastic component is maintained
in the positioning position.
Inventors: |
CHEN; JUEI-PIN; (TAICHUNG
CITY, TW) ; WU; HUAI-AN; (TAICHUNG CITY, TW) ;
SHEN; WEI; (TAICHUNG CITY, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FORWARD OPTICS CO., LTD. |
TAICHUNG CITY |
|
TW |
|
|
Family ID: |
1000005666540 |
Appl. No.: |
16/869985 |
Filed: |
May 8, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05K 2203/1121 20130101;
H05K 3/22 20130101; H05K 2203/166 20130101 |
International
Class: |
H05K 3/22 20060101
H05K003/22 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 2, 2020 |
TW |
109100083 |
Claims
1. A method for bonding a plastic component to a printed circuit
board, comprising the steps of: a) providing the plastic component,
the printed circuit board, and at least one positioning member,
wherein the plastic component includes a first end surface, which
faces the printed circuit board when the plastic component is
disposed above the printed circuit board, and at least one
fastening hole formed in the first end surface, the printed circuit
board includes a substrate, and at least one metal base which is
disposed on the substrate and which has a connecting surface
connected to the substrate and a first bonding surface opposite to
the connecting surface, and the at least one positioning member is
fastened in the at least one fastening hole and is made of a metal
material, and includes a second bonding surface exposed from the
first end surface; b) disposing between the first bonding surface
of the at least one metal base of the printed circuit board and the
second bonding surface of the at least one positioning member, at
least one welding layer made of a welding metal, which has a
melting point lower than a thermal deformation temperature of the
plastic component and which is solid at a predetermined temperature
range; c) positioning the plastic component and the printed circuit
board relative to each other, such that the plastic component is in
a positioning position relative to the printed circuit board; d)
melting the at least one welding layer using a heating device while
the plastic component is maintained in the positioning position, so
as to permit the first bonding surface of the at least one metal
base of the printed circuit board to adhere to the second bonding
surface of the at least one positioning member via the at least one
welding layer; and e) cooling the at least one welding layer while
the plastic component is maintained in the positioning position so
as to solidify the at least one welding layer.
2. The method according to claim 1, wherein in step a), the plastic
component includes a first positioning portion and at least one
fastening portion, which is formed with the at least one fastening
hole, and the printed circuit board further includes an electronic
element disposed on the substrate and having a second positioning
portion, and in step c), when the plastic component is in the
positioning position, the first positioning portion of the plastic
component is aligned with the second positioning portion of the
electronic element, and the first bonding surface of the at least
one metal base of the printed circuit board is aligned with the
second bonding surface of the at least one positioning member, so
as to permit the at least one welding layer to be sandwiched
between the first bonding surface and the second bonding
surface.
3. The method according to claim 2, wherein in step a), the first
positioning portion is configured as a lens.
4. The method according to claim 1, wherein in step a), the at
least one positioning member is fitted in the at least one
fastening hole, respectively.
5. The method according to claim 1, wherein in step a), the plastic
component further includes a second end surface opposite to the
first end surface, the at least one fastening hole extends from the
first end surface to the second end surface, and the at least one
positioning member extends through the at least one fastening hole
to terminate at a thermal conductive surface that is exposed from
the second end surface, and in step d), the heating device is
disposed on the thermal conductive surface of the at least one
positioning member so as to transmit heat from the thermal
conductive surface to the at least one welding layer.
6. The method according to claim 5, wherein in step a), the plastic
component includes a first positioning portion and at least one
fastening portion which is formed with the at least one fastening
hole.
7. The method according to claim 1, wherein in step a), the plastic
component is formed integrally with the at least one positioning
member via molding.
8. The method according to claim 1, wherein in step a), the at
least one positioning member is made of the welding metal.
9. The method according to claim 8, wherein in step a), the at
least one positioning member is made of the welding metal and is
fastened in the at least one fastening hole by melting the welding
metal to form a molten welding metal so as to permit the molten
welding metal to fill in the at least one fastening hole and then
solidifying the molten welding metal via cooling.
10. The method according to claim 1, wherein in step b), each of
the first bonding surface of the at least one metal base and the
second bonding surface of the at least one positioning member is
disposed with the welding layer, and in step d), the welding layer
disposed on the first bonding surface of the at least one metal
base and the welding layer disposed on the second bonding surface
of the at least one positioning member are molten so as to be
welded together.
11. The method according to claim 1, wherein in step b), the
predetermined temperature range is from -20.degree. C. to
200.degree. C.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority of Taiwanese Invention
Patent Application No. 109100083, filed on Jan. 2, 2020.
FIELD
[0002] The disclosure relates to a method for bonding a plastic
component to a printed circuit board, and more particularly to a
method for bonding a plastic component to a printed circuit board
in an optical system.
BACKGROUND
[0003] Recently, there is a tendency for increasing the running
frequency of optical communication module due to increased demand
for data traffic, such that the volume and the work surface of
relevant components are decreased gradually. Therefore, the
positioning relationship among the components needs to be more
precise, so as to reduce the loss of the laser light transmitting
among the components and to maintain sufficient energy for message
transmission.
[0004] A conventional optical communication module includes a
light-guiding plastic component and a printed circuit board, which
have to be bonded to each other and satisfy a very precise
positioning relationship to as to perform the originally designed
functions. A conventional method for bonding the plastic component
to the printed circuit board is conducted using an ultraviolet (UV)
glue. Specifically, the relative position between the plastic
component and the printed circuit board is adjusted precisely, and
the transmission power of the laser light during the adjustment is
monitored at the same time. When satisfactory conditions are
achieved, the UV glue is added between the plastic component and
the printed circuit board, followed by curing the UV glue via
irradiation of UV light so as to complete the bonding process.
However, the UV light is easily blocked by the plastic component
and the printed circuit board, causing insufficient irradiation
energy for fully curing the UV glue. In addition, when the UV glue
is relatively thick, the deeper portion of the UV glue would not be
cured completely due to the irradiation strength of the UV light
being decreased gradually along a thickness direction of the UV
glue. The incompletely cured portion of the UV glue would not be
able to perform the curing function, or would only cure gradually
after the bonding process is finished, causing changes in the
volume of the UV glue and the relative position between the plastic
component and the printed circuit board, which results in
degradation of the functions thereof. Although the aforesaid
disadvantages can be solved by increasing the preciseness of the
relative position and the time period for UV irradiation, the
complexity and the operation time for assembling the plastic
component and the printed circuit board would be increased.
[0005] Another conventional method for bonding the plastic
component to the printed circuit board is conducted using a thermal
curing adhesive, which can avoid the aforesaid blocking problem
caused by using the UV glue. However, after the thermal curing
adhesive is applied, the plastic component and the printed circuit
board together with the thermal curing adhesive applied
therebetween are required to be placed in an elevated temperature
environment for curing the thermal curing adhesive. The density
variation of the thermal curing adhesive is relatively significant
during the curing process compared to that of the UV glue,
resulting in a relatively significant volume variation. In
addition, during the curing process conducted at the elevated
temperature, the relative position between the plastic component
and the printed circuit board would be changed, resulting in
degradation of the functions thereof.
[0006] In addition, the performance of both the UV glue and the
thermal curing adhesive that are made of polymeric material is
easily affected by environmental factors. For example, the water
contents of the UV glue and the thermal curing adhesive are
increased after absorption of moisture in the air, causing
variation in the volumes of the UV glue and the thermal curing
adhesive. Furthermore, the UV glue and the thermal curing adhesive
would degrade easily due to severe temperature variation, resulting
in reduction of the bonding capability thereof, and thus, the
functions and reliability of the products made thereby would be
reduced compared to those of the originally designed products.
SUMMARY
[0007] Therefore, an object of the disclosure is to provide a
method for bonding a plastic component to a printed circuit board
to overcome the shortcomings described above.
[0008] According to the disclosure, there is provided a method for
bonding a plastic component to a printed circuit board, which
includes the steps of:
[0009] a) providing the plastic component, the printed circuit
board, and at least one positioning member, wherein [0010] the
plastic component includes a first end surface, which faces the
printed circuit board when the plastic component is disposed above
the printed circuit board, and at least one fastening hole formed
in the first end surface, [0011] the printed circuit board includes
a substrate, and at least one metal base which is disposed on the
substrate and which has a connecting surface connected to the
substrate and a first bonding surface opposite to the connecting
surface, and [0012] the at least one positioning member is fastened
in the at least one fastening hole and is made of a metal material,
and includes a second bonding surface exposed from the first end
surface;
[0013] b) disposing between the first bonding surface of the at
least one metal base of the printed circuit board and the second
bonding surface of the at least one positioning member, at least
one welding layer made of a welding metal, which has a melting
point lower than a thermal deformation temperature of the plastic
component and which is solid at a predetermined temperature
range;
[0014] c) positioning the plastic component and the printed circuit
board relative to each other, such that the plastic component is in
a positioning position relative to the printed circuit board;
[0015] d) melting the at least one welding layer using a heating
device while the plastic component is maintained in the positioning
position, so as to permit the first bonding surface of the at least
one metal base of the printed circuit board to adhere to the second
bonding surface of the at least one positioning member via the at
least one welding layer; and
[0016] e) cooling the at least one welding layer while the the
plastic component is maintained in the positioning position so as
to solidify the at least one welding layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Other features and advantages of the disclosure will become
apparent in the following detailed description of the embodiments
with reference to the accompanying drawings, of which:
[0018] FIG. 1 is a flow diagram of a method for bonding a plastic
component to a printed circuit board according to the
disclosure;
[0019] FIG. 2 is a schematic view illustrating a first embodiment
of the method for bonding a plastic component to a printed circuit
board according to the disclosure;
[0020] FIG. 3 is a schematic view illustrating a second embodiment
of the method for bonding a plastic component to a printed circuit
board according to the disclosure; and
[0021] FIGS. 4 and 5 are schematic views illustrating a third
embodiment of the method for bonding a plastic component to a
printed circuit board according to the disclosure.
DETAILED DESCRIPTION
[0022] Before the disclosure is described in greater detail, it
should be noted that where considered appropriate, reference
numerals or terminal portions of reference numerals have been
repeated among the figures to indicate corresponding or analogous
elements, which may optionally have similar characteristics.
[0023] Referring to FIGS. 1 and 2, a first embodiment of a method
for bonding a plastic component 1 to a printed circuit board 2
includes the steps of: a) providing the plastic component 1, the
printed circuit board 2, and at least one positioning member 3, b)
disposing at least one welding layer 4, c) positioning the plastic
component 1 and the printed circuit board 2 relative to each other,
d) melting the at least one welding layer 4, and e) cooling the at
least one welding layer 4.
[0024] In step a), the plastic component 1, the printed circuit
board 2, and the at least one positioning member 3 are
provided.
[0025] The plastic component 1 includes a first end surface 121 and
at least one fastening hole 122 formed in the first end surface
121. The first end surface 121 faces the printed circuit board 2
when the plastic component 1 is disposed above the printed circuit
board 2. Two fastening holes 122 are shown in FIG. 2. It should be
noted that the number of the fastening hole 122 is not limited,
which may be more than two. In addition, the plastic component 1
includes a first positioning portion 11 and at least one fastening
portion 12. The first positioning portion 11 is configured as a
lens. Two fastening portions 12 are shown in FIG. 2. It should be
noted that the number of the fastening portion 12 is not limited,
which may be more than two. Each of the fastening portions 12 is
formed with a corresponding one of the fastening holes 122.
[0026] The printed circuit board 2 includes a substrate 21, an
electronic element 23, and at least one metal base 22 disposed on
the substrate 21. Two metal bases 22 are shown in FIG. 2. It should
be noted that the number of the metal base 22 is not limited, which
may be more than two. Each of the metal bases 22 has a connecting
surface 221 connected to the substrate 21, and a first bonding
surface 222 opposite to the connecting surface 221. The electronic
element 23 is disposed on the substrate 21 and has a second
positioning portion 231.
[0027] The at least one positioning member 3 is fastened in the at
least one fastening hole 122 and is made of a metal material. In
this embodiment, the at least one positioning member 3 is fitted in
the at least one fastening hole 122, respectively. Specifically,
two positioning members 3 are shown in FIG. 2. It should be noted
that the number of the positioning member 3 is not limited, which
may be more than two. Each of the positioning members 3 is fitted
in a corresponding one of the fastening holes 122, and includes a
second bonding surface 31 exposed from the first end surface
121.
[0028] It should be noted that the number of the first positioning
portion 11 and the corresponding number of the second positioning
portion 231 may be increased for the intended functions, if
necessary. Each of the positioning members 3 is illustrated as a
metal block in the embodiment. It should be noted that the
positioning member 3 may be a metal sheet, a metal strip, or other
structures.
[0029] In step b), at least one welding layer 4 is disposed between
the first bonding surface 222 of each of the metal bases 22 of the
printed circuit board 2 and the second bonding surface 31 of a
corresponding one of the positioning members 3. In this embodiment,
two welding layers 4 are disposed between the first bonding surface
222 of each of the metal bases 22 and the second bonding surface 31
of a corresponding one of the positioning members 3. Each of the
first bonding surface 222 of the at least one metal base 22 and the
second bonding surface 31 of the at least one positioning member 3
is disposed with the welding layer 4. In other words, the first
bonding surface 222 of each of the metal bases 22 is disposed with
one of the welding layers 4 thereon, and the second bonding surface
31 of each of the positioning members 3 is disposed with the other
one of the welding layers 4 thereon.
[0030] It should be noted that in step b), when only one welding
layer 4 is disposed between the first bonding surface 222 of each
of the metal bases 22 and the second bonding surface 31 of a
corresponding one of the positioning members 3, the welding layer 4
may be disposed on the first bonding surface 222 or the second
bonding surface 31.
[0031] The welding layer 4 is made of a welding metal, which has a
melting point lower than a thermal deformation temperature of the
plastic component 1 and which is solid at a predetermined
temperature range that includes room temperature (usually
25.degree. C.).
[0032] It should be noted that the predetermined temperature range
is determined on a basis of the product to be processed and
operated. In certain embodiments, the predetermined temperature
range is from -20.degree. C. to 200.degree. C., and the melting
point of the welding metal should be higher than 200.degree. C.
[0033] In step c), the plastic component 1 and the printed circuit
board 2 are positioned relative to each other, such that the
plastic component 1 is in a positioning position relative to the
printed circuit board 2. When the plastic component 1 is in the
positioning position, the first positioning portion 11 of the
plastic component 1 is aligned with the second positioning portion
231 of the electronic element 23, and the first bonding surface 222
of each of the metal bases 22 of the printed circuit board 2 is
aligned with the second bonding surface 31 a corresponding one of
the positioning members 3, so as to permit the welding layers 4 to
be sandwiched between the first bonding surface 222 and the second
bonding surface 31.
[0034] In step d), the welding layers 4 are molted using a heating
device 9 while the plastic component 1 is maintained in the
positioning position, so as to permit the first bonding surface 222
of each of the metal bases 22 of the printed circuit board 2 to
adhere to the second bonding surface 31 of a corresponding one of
the positioning members 3 via the welding layers 4. Specifically,
the welding layer 4 disposed on the first bonding surface 222 of
the at least one metal base 22 and the welding layer 4 disposed on
the second bonding surface 31 of the at least one positioning
member 3 are molten so as to be welded together. The heating device
9 used in the embodiment is a laser-emitting device. The thermal
energy produced by the laser-emitting device is transmitted to the
welding layers 4 via thermal radiation. It should be noted that the
thermal energy produced by the heating device 9 may be transmitted
via the other manners depending on the type of the heating device
9, such as via thermal convection or thermal conduction.
[0035] Since the positioning members 3 are made of a metal
material, the welding layer 4 made of a welding metal may be
adhered to the second bonding surface 31 thereof without the
problem caused by bonding a metal material to a non-metal
material.
[0036] In step e), the welding layers 4 are cooled while the
plastic component 1 is maintained in the positioning position so as
to solidify the welding layers 4.
[0037] Since the welding metal for the welding layer 4 has superior
thermal conductivity, the welding layer 4 can be heated and cooled
in a fast and evenly manner. Therefore, the aforesaid incomplete
curing problem of the prior art can be avoided, and the operation
time for bonding the plastic component 1 to the printed circuit
board 2 can be decreased. In addition, the welding metal has a
relatively low density variation caused by the temperature change
as compared to that of the polymeric material. Therefore, the
volume of the the welding layer 4 can be maintained substantially
constant during the bonding of the plastic component 1 to the
printed circuit board 2. Furthermore, since the welding metal is
substantially not affected by moisture, the functional degradation
problem of the prior art can be overcome. In view of the aforesaid,
the positioning relationship between the plastic component 1 and
the printed circuit board 2 will not be affected by the welding
layer 4, and thus, the preciseness in positioning and the
reliability of the product made thereby can be enhanced
significantly.
[0038] Referring to FIG. 3, a second embodiment of the method for
bonding a plastic component 1 to a printed circuit board 2 is
similar to the first embodiment except the following
differences.
[0039] In step a) of the second embodiment, the plastic component 1
is formed integrally with the at least one positioning member 3 via
molding, and further includes a second end surface 123 opposite to
the first end surface 121. The at least one fastening hole 122
extends from the first end surface 121 to the second end surface
123. The at least one positioning member 3 extends through the at
least one fastening hole 122 to terminate at a thermal conductive
surface 32 that is exposed from the second end surface 123.
[0040] In step d) of the second embodiment, the heating device 9 is
disposed on the thermal conductive surface 32 of the at least one
positioning member 3 so as to transmit heat from the thermal
conductive surface 32 to the at least one welding layer 4 via
thermal conduction.
[0041] Referring to FIGS. 4 and 5, a third embodiment of the method
for bonding a plastic component 1 to a printed circuit board 2 is
similar to the first embodiment except the following
differences.
[0042] In step a) of the third embodiment, the at least one
positioning member 3 is made of the welding metal 7, and is
fastened in the at least one fastening hole 122. To be specific,
the welding metal 7 is molten to form a molten welding metal so as
to permit the molten welding metal to fill in the at least one
fastening hole 122 and then the molten welding metal is solidified
via cooling to form the at least one positioning member 3 fastened
in the at least one fastening hole 122.
[0043] In step d) of the third embodiment, the heating device 9 is
a hot air generator, and the at least one welding layer 4 is molten
by the hot air generated by the hot air generator via thermal
convection.
[0044] In the description above, for the purposes of explanation,
numerous specific details have been set forth in order to provide a
thorough understanding of the embodiments. It will be apparent,
however, to one skilled in the art, that one or more other
embodiments may be practiced without some of these specific
details. It should also be appreciated that reference throughout
this specification to "one embodiment," "an embodiment," an
embodiment with an indication of an ordinal number and so forth
means that a particular feature, structure, or characteristic may
be included in the practice of the disclosure. It should be further
appreciated that in the description, various features are sometimes
grouped together in a single embodiment, figure, or description
thereof for the purpose of streamlining the disclosure and aiding
in the understanding of various inventive aspects, and that one or
more features or specific details from one embodiment may be
practiced together with one or more features or specific details
from another embodiment, where appropriate, in the practice of the
disclosure.
[0045] While the disclosure has been described in connection with
what are considered the exemplary embodiments, it is understood
that this disclosure is not limited to the disclosed embodiments
but is intended to cover various arrangements included within the
spirit and scope of the broadest interpretation so as to encompass
all such modifications and equivalent arrangements.
* * * * *