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Digital Camera Patent Abstract
A digital camera module (200) includes a carrier (20), an image
sensor chip (30), a number of wires (50), a holder (60), and a lens
module (70). The carrier includes a base (21) and a leadframe (23)
embedded in the base. The base includes a board (211), a sidewall
(213) and a cavity (24). The leadframe includes a number of conductive
leads (233) spaced from each other. Each lead has a first terminal
portion (235), a second terminal portion (236), and an interconnecting
portion (237) connecting the first and second terminal portions.
The chip is mounted on the carrier, and has an active area (301).
The wires electrically connect the chip and the leadframe. The holder
is mounted to the carrier to close the cavity. The lens module is
received in the holder and guides light to the active area of the
chip.
Digital Camera Patent Claims
1. A digital camera module comprising: a carrier, the carrier comprising
a base and a leadframe, the base having a board, a sidewall extending
from a top surface of the board and a cavity cooperatively defined
by the board and the sidewall, the leadframe comprising a plurality
of conductive leads, the conductive leads of the leadframe being
embedded in the base and spaced from each other, each conductive
lead having a first terminal portion exposed from a top surface
of the sidewall of the base, a second terminal portion exposed from
a bottom surface of the board, and an interconnecting portion connecting
the first and second terminal portions; an image sensor chip, the
chip mounted on the base and received in the cavity, the chip having
an active area and a plurality of contacts; a plurality of wires,
the wires electrically connecting the contacts of the chip and the
first terminal portions of the leadframe; a holder, the holder being
mounted to the carrier to close the cavity of the carrier; and a
lens module, the lens module being received in the holder and being
configured for guiding light to the active area of the chip.
2. The digital camera module as claimed in claim 1, wherein the
leadframe is manufactured by punching or etching on a metal sheet,
the base is made of plastic materials and encapsulates the leadframe
via injection molding.
3. The digital camera module as claimed in claim 2, wherein the
first and second terminal portions are parallel to and spaced from
each other, and the interconnecting portions are slanted relative
to the first and second terminal portions.
4. The digital camera module as claimed in claim 3, wherein the
sidewall of the base comprises a front sidewall portion, a rear
sidewall portion parallel to the front sidewall portion, a left
sidewall portion, and a right sidewall portion parallel to the left
sidewall portion, the conductive leads are divided into two groups
which are symmetrically arranged, and the first terminal portions
of the two group of the conductive leads are exposed from a pair
of parallel sidewall portions.
5. The digital camera module as claimed in claim 4, wherein the
sidewall further comprises a pair of slots, the two slots are defined
in another pair of the parallel sidewall portions.
6. The digital camera module as claimed in claim 3, wherein the
contacts of the chip are correspondingly divided into two groups
which are arranged symmetrically on periphery of a top surface of
the chip, and each group of the contacts is disposed near to a group
of the first terminal portions of the conductive leads.
7. The digital camera module as claimed in claim 4, wherein the
holder defines a seat portion for receiving the carrier, and the
seat portion comprises a first step section and a second step section,
and the second step section has a step surface from which the first
step section extends from, and the first step section surrounds
and is attached to an outer periphery of the sidewall of the base,
the step surface is attached to the top surface of the base.
8. The digital camera module as claimed in claim 7, wherein the
seat portion has a through hole defined therein, and the through
hole is enclosed by the lens module.
9. The digital camera module as claimed in claim 7, wherein the
holder further has a cylinder portion projecting from the seat portion,
and the cylinder portion receives the lens module therein.
10. The digital camera module as claimed in claim 7, wherein the
second step section has a pair of recessed portion defined therein,
and the recessed portions receive the wires therein.
11. The digital camera module as claimed in claim 7, wherein the
second step section has a pair of ribs projecting form the step
surface, and the ribs engage with the slots of the sidewall of the
base.
12. The digital camera module as claimed in claim 2, wherein the
leadframe further comprises a die pad configured for dissipating
thermal energy, and the die pad is embedded in a middle portion
of the board with a top surface and bottom surface thereof exposed
through the board.
13. The digital camera module as claimed in claim 1, wherein the
cavity has a uniform cross section between the board and the sidewall.
14. The digital camera module as claimed in claim 1, wherein the
lens module comprises a barrel and at least one lens received in
the barrel.
Digital Camera Patent Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to a co-pending U.S. Patent
Applications (Attorney Docket No. US7598), entitled "IMAGE
SENSOR CHIP PACKAGE", by Steven Webster et al. Such application
has the same assignee as the present application and has been concurrently
filed herewith. The disclosure of the above identified application
is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention generally relates to camera modules,
and more particularly to a digital camera module suitable for portable
electronic devices such as mobile phones, personal digital assistants
(PDAs) and the like.
BACKGROUND
[0003] Generally, digital cameras are image recording media capable
of photographing a plurality of still images without using film.
Such a digital camera typically uses an image pickup device, which
is a kind of semiconductor device, such as a charge coupled device
(CCD) or complementary metal oxide semiconductor (CMOS). In the
digital camera, an object image formed on the image pickup device
through a lens is converted into an electrical signal by the image
pickup device, and the electrical signal is stored as a digital
signal in a mobile phone or PDA in which the digital camera is mounted.
In order to protect the image pickup device from contamination or
pollution (i.e. from dust or water vapor), the image pickup device
is generally sealed in a structural package.
[0004] A typical image sensor chip package 100 is illustrated in
FIG. 1. The image sensor chip package 100 is constructed to include
a base 10, a chip 12, a plurality of wires 13, an adhesive glue
14 and a cover 15. The base 10 includes a board portion 101, a frame
portion 102 upwardly extending from a periphery of the board portion
101, and a cavity 103 cooperatively formed by the board portion
101 and the frame portion 102. A plurality of top contacts 104 and
bottom contacts 105 are respectively mounted on two sides of the
board portion 101, and the top contacts 104 are contained in the
cavity 103. A plurality of conductive interconnecting portions 106
are arranged inside the board portion 101 so as to electrically
connect the top and bottom contacts 104, 105. The chip 12 includes
an active area 121 and a number of pads 122 formed thereon. The
chip 152 is received in the cavity 103 and adhered to the board
portion 101 of the base 10. The wires 13 are provided to electrically
connect the pads 122 of the chip 12 and the top contacts 104 of
the base 10. The cover 15 is transparent and secured to the top
of the frame portion 102 via the adhesive glue 14, thereby hermetically
sealing the cavity 103 and allowing light beams to pass therethrough.
[0005] In the foresaid package 100, the base 10 is essentially
made from ceramic, which is expensive and accordingly results in
increased cost of the package 100. During the process of forming
the contacts 104, 105 and the interconnecting portions 106 on the
base 10, firstly a number of interconnection holes are punched in
the base 10, secondly, the base 10 is copper plated, via electroless
or electrolytic deposition onto the surface of the base 10 and onto
the surfaces created by the interconnecting holes. Finally, the
contacts 104, 105 are formed by means of etching. Accordingly, the
contacts 104, 105 and the interconnecting portions 106 are electrically
connected with each other. It is obvious that this method of forming
the contacts 104, 105 and the interconnecting portions 106 is complex
and as a result it is expensive. Furthermore, water vapor can enter
the cavity 103 via the interconnection portions 106. Thus, the chip
12 may become polluted, and even be damaged.
[0006] Additionally, the cavity 103 of the base 10 must contain
both of the top contacts 104 and the chip 12 therein, and there
must be a space between an outer periphery of the chip 12 and an
inner periphery of the frame portion 102 of the base 10 for allowing
movement of a wire bonding tool, which accordingly results in a
relatively large sized package 100 relative to the volume of the
chip 12.
[0007] Furthermore, the relatively large volume of the package
100 results in more dust-particles adhering to the cover 15, the
board portion 101 and the frame portion 102 of the base 10. Thus,
more dust-particles will drop onto the chip 12. The dust-particles
obscure the optical path and produce errors in the image sensing
process. Accordingly, the quality and/or reliability of the package
100 may be adversely affected.
[0008] Therefore, a digital camera module with an improved image
sensor chip package is desired in order to overcome the above-described
shortcomings.
SUMMARY OF THE INVENTION
[0009] In one aspect, digital camera module includes a carrier,
an image sensor chip, a number of wires, a holder and a lens module.
The carrier includes a base and a leadframe embedded in the base.
The base has a board, a sidewall extending from a top surface of
the board and a cavity cooperatively defined by the board and the
sidewall. The leadframe includes a plurality of conductive leads
spaced from each other. Each conductive lead has a first terminal
portion exposed from a top surface of the sidewall of the base,
a second terminal portion exposed through a bottom surface of the
board, and an interconnecting portion connecting the first and second
terminal portion. The chip is mounted on the base and received in
the cavity, and includes an active area and a plurality of contacts.
The wires electrically connect the contacts of the chip and the
first terminal portions of the leadframe. The holder is mounted
on the carrier to enclose the cavity of the carrier. The lens module
is received in the holder and guides light to the active area of
the chip.
[0010] Other advantages and novel features will become more apparent
from the following detailed description when taken in conjunction
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Many aspects of the present digital camera module can be
better understood with reference to the following drawings. The
components in the drawings are not necessarily drawn to scale, the
emphasis instead being placed upon clearly illustrating the principles
of the digital camera module. Moreover, in the drawings, like reference
numerals designate corresponding parts throughout the several views.
[0012] FIG. 1 is a schematic, cross-sectional view of a typical
image sensor chip package;
[0013] FIG. 2 is a schematic, top plan view of a digital camera
module according to a preferred embodiment, wherein a holder and
a lens module of the digital camera module are not shown;
[0014] FIG. 3 is a cross-sectional view of the digital camera module
in FIG. 2 along a line III-III, wherein the holder and the lens
module are shown; and
[0015] FIG. 4 is a cross-sectional view of the digital camera module
in FIG. 2 along a line IV-IV, wherein the holder and the lens module
are shown.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] Referring to FIGS. 2 through 4, a digital camera module
200 in accordance with a preferred embodiment is illustrated. The
digital camera module 200 is configured (i.e. structured or arranged)
for including an image sensor chip package (not labeled) and a lens
module 70, wherein the image sensor chip package includes a carrier
20, a chip 30, a number of bonding wires 50 and a holder 60.
[0017] The carrier 20 of the image sensor chip package includes
a plastic base 21 and a leadframe (not labeled). The leadframe and
the plastic base 21 cooperatively form the carrier 20 by injection
molding.
[0018] The base 21 is essentially made from plastic materials such
as polyphenylene oxide (PPO), polyphenylene sulfide (PPS) and the
like. The base 21 may have various perimeter shapes, such as a square,
rectangular, a circular etc. The base 21 includes a base board 211,
a sidewall 213 upwardly extending from a periphery of the base board
211, and a cavity 24 cooperatively formed by the base board 211
and the sidewall 213 for receiving electronic components. As shown
in FIG. 2, the sidewall 213 includes a front sidewall portion 2131,
a rear sidewall portion 2133 positioned opposite to the front sidewall
portion 2131, a left sidewall portion 2132, and a right sidewall
portion 2134 positioned opposite to the left sidewall portion 2134.
The top surfaces of two opposite sidewall portions of the sidewall
213, such as the left and right sidewall portion 2132, 2134, each
have a slot 217 longitudinally defined therein. The cavity 24 has
a uniform cross section between the base board 211 and the sidewall
213.
[0019] Referring to FIGS. 3 and 4, the leadframe is made of conductive
metal material, which has good electrical conductivity and thermal
conductivity, such as copper or iron-nickel alloy, in order to enhance
the signal transmission characteristic and thermal transmission
characteristics of the package. The leadframe includes a die pad
231 and a number of conductive leads 233. The conductive leads 233
are formed by either punching or etching on a metal sheet. Each
of the conductive leads 233 includes a first terminal portion 235,
a second terminal portion 236 and a connecting portion 237, and
the connecting portion 237 interconnecting the first and second
terminal portions 235, 236. The first and second terminal portions
235, 236 are spaced apart and aligned parallel to each other. The
interconnecting portions 237 are slanted relative to the first and
second terminal portions 235, 236. Correspondingly, the conductive
leads 233 are divided into two groups. The two groups are symmetrically
arranged and the conductive leads 233 in the same group are parallel
to and spaced from each other. The die pad 231 is disposed between
the two groups of the conductive leads 233, and a bottom surface
of the die pad 231, and is level with the bottom surfaces of the
second terminal portions 236 of the conductive leads 233 whilst
a top surface of the die pad 231 is at a higher level than that
of a top surface of each second terminal portions 236.
[0020] During injection molding, the plastic base 21 encapsulates
the leadframe, wherein the die pad 231 is disposed in a middle portion
of the base board 211 with the top and bottom surfaces thereof exposed
through the base board 211, an upper surface of each first terminal
portion 235 is exposed from the top surfaces of the sidewall portions
without a slot 217 defined therein, for example, the top surfaces
of the front and rear sidewall portions 2131, 2133, and each second
terminal portion 236 are exposed from the bottom surface of the
base board 211. The first and second terminal portions 235, 236
are both configured for electrically connecting with other electronic
components, for example the first terminal portions 235 can be used
to electrically connect to a chip and the second terminal portions
236 can be used to electrically connect with a printed circuit board
(PCB), thereby transmitting signals from the chip to the PCB via
the leadframe.
[0021] The image sensor chip 30 is received in the cavity 24, and
is attached to the base board 211. A top surface of the image sensor
chip 30 is arranged with an active area 301 and a number of contacts
302. The active area 301 is disposed in a middle portion of the
top surface of the chip 30. The contacts 302 are divided into two
groups, and the two groups of contacts 302 are symmetrically disposed
and formed at regular intervals along a peripheral portion of the
top surface of the chip 30.
[0022] The wires 50 can be made of a conductive material with good
electric conductivity, such as gold or aluminum alloy. One end of
each wire 50 is connected/joined with a respective contact 302 of
the image sensor chip 30, and the other end of the wire 50 is connected/joined
with a respective top surface of a first terminal portion 235 of
the leadframe.
[0023] The holder 60 is constructed to include a seat portion 61,
a cylinder portion 62 projecting from the seat portion 61, and a
through hole 63 penetrating through the seat portion 61 and the
cylinder portion 62. The holder 60 can has a one-piece shape, for
example, in FIGS. 3 and 4, the seat portion 61 and the cylinder
portion 62 is formed by injection molding. Alternatively, the holder
60 can be assembled from a separate seat portion 61 and a separate
cylinder portion 62. The seat portion 61 is designed for housing
the carrier 20 with the chip 30 mounted thereon. The seat portion
61 includes a transparent board 610 received in the through hole
63 to enclose an end where the cylinder portion 62 projects. The
seat portion further includes a first step section 611 and a second
step section 613, positioned opposite to the cylinder portion 62.
An inner periphery of the first step section 611 has a dimension
equal to that of an outer periphery of the carrier 20. An inner
periphery of the second step section 613 has a dimension smaller
than that of the outer periphery of the carrier 20. The second step
section 613 includes a step surface 615 from which the first step
section 611 extends. The step surface 615 has two recessed portion
617 defined therein for receiving the wires 50, and two ribs 619
projecting therefrom for engaging with the slots 217 of the carrier
20. The cylinder portion 62 is configured for receiving the lens
module 70 therein, and has an internal thread formed thereon.
[0024] The seat portion 61 of the holder receives the carrier 20
mounted with the chip 30 therein, wherein the inner periphery of
the first step section 611 is adhered to the outer periphery of
the carrier 20, the step surface 615 of the seat portion 61 is adhered
to the top surface of the sidewall 213, each recessed portion 623
receives a group of wires 50, each rib 619 of the holder 60 is adhered
to and engaged with a corresponding slot 217 of the carrier 20,
and the transparent board 610 is positioned above the active area
301 of chip 30.
[0025] The lens module 70 includes a barrel 71 and at least one
lens 72 received in the barrel 71. The barrel 71 has an external
thread formed on an outside thereof. The lens module 70 is received
in the cylinder portion 62 of the holder 60, wherein the external
thread of the barrel 71 engages with the internal thread of the
cylinder portion 62, and the at least one lens 72 faces towards
the active area 301 of the chip 30 to form an image on the active
area 301.
[0026] In an alternative embodiment, the cylinder portion 62 can
be omitted and the lens module 70 can be directly mounted to the
seat portion 61. Furthermore, the lens module 70 can be omitted
while a lens is received in the through hole 63 instead of the transparent
board 610 to enclose the seat portion 61 and form a focused image
on the active area 301 of the chip 30.
[0027] The base 21 of the carrier 20 is made of plastic material,
which is much cheaper than ceramic, and the carrier 20 is formed
by injection molding technology, which is a relative simple method
for manufacturing the carrier 20, thus, the cost of the digital
camera module 200 is accordingly decreased.
[0028] The leadframe of the carrier 20 is solid and substantially
encapsulated by the base 21, so it is difficult for water vapor
to penetrate into the package to pollute the chip 30, thereby enhancing
the reliability of the digital camera module 200.
[0029] The top surfaces of the first terminal portions 235 of the
leadframe act as connecting pads, accordingly there is no space
restriction on the movement of wire bonding tools. Thus, the size
of the carrier 20 can be sufficiently minimized to approach the
size of the chip 30, and the volume of the digital camera module
can also be minimized.
[0030] In addition, a relative small volume of the digital camera
module 200 contains relatively little dust particles therein, the
pollution and/or contamination of the active area 301 is reduced
and the quality and reliability of the digital camera module 200
is much improved.
[0031] It is believed that the present embodiments and their advantages
will be understood from the foregoing description, and it will be
apparent that various changes may be made thereto without departing
from the spirit and scope of the invention or sacrificing all of
its material advantages, the examples hereinbefore described merely
being preferred or exemplary embodiments of the invention. |