U.S. patent application number 13/071892 was filed with the patent office on 2012-09-27 for miniature wafer-level camera modules.
Invention is credited to Kenneth Kubala, Paulo E. X. Silveira, Satoru Tachihara.
Application Number | 20120242814 13/071892 |
Document ID | / |
Family ID | 46877033 |
Filed Date | 2012-09-27 |
United States Patent
Application |
20120242814 |
Kind Code |
A1 |
Kubala; Kenneth ; et
al. |
September 27, 2012 |
Miniature Wafer-Level Camera Modules
Abstract
In one aspect, a method includes providing a lens substrate
having an array of lenses. The lens substrate includes an overflow
region next to each lens of the array. Each overflow region
includes an overflow lens material. The method also includes
separating the lens substrate into a plurality of smaller lens
substrates. Each of the smaller lens substrates has one of the
single lens and the plurality of stacked lenses. Separating the
lens substrate into the smaller lens substrates may include
removing or substantially removing the overflow regions. In one
aspect, the method may be performed as a method of making a
miniature camera module. Other methods are also described, as are
miniature camera modules.
Inventors: |
Kubala; Kenneth; (Boulder,
CO) ; Silveira; Paulo E. X.; (Santa Clara, CA)
; Tachihara; Satoru; (Boulder, CO) |
Family ID: |
46877033 |
Appl. No.: |
13/071892 |
Filed: |
March 25, 2011 |
Current U.S.
Class: |
348/76 ; 156/250;
29/700; 348/374; 348/E5.024; 348/E7.085; 83/13 |
Current CPC
Class: |
H04N 2005/2255 20130101;
H01L 27/14625 20130101; B29D 11/00307 20130101; H04N 5/2254
20130101; Y10T 29/53 20150115; Y10T 156/1052 20150115; Y10T 83/04
20150401; H04N 5/2251 20130101; B26F 1/38 20130101; H04N 5/2253
20130101; H04N 5/2257 20130101; H01L 27/14636 20130101; H01L
27/14643 20130101; B29D 11/00298 20130101; H01L 27/14685 20130101;
H01L 27/14698 20130101 |
Class at
Publication: |
348/76 ; 348/374;
156/250; 29/700; 83/13; 348/E05.024; 348/E07.085 |
International
Class: |
H04N 5/225 20060101
H04N005/225; B32B 38/04 20060101 B32B038/04; B26D 3/00 20060101
B26D003/00; H04N 7/18 20060101 H04N007/18 |
Claims
1. A method comprising: providing a lens substrate having an array
of lenses, the lens substrate including an overflow region next to
each lens of the array, each overflow region including an overflow
lens material; and separating the lens substrate into a plurality
of smaller lens substrates, each of the smaller lens substrates
having one of a single lens and a plurality of stacked lenses,
wherein separating the lens substrate into the plurality of smaller
lens substrates includes substantially removing the overflow
regions.
2. The method of claim 1, wherein separating the lens substrate
into the smaller lens substrates comprises dicing the lens
substrate.
3. The method of claim 1, wherein separating the lens substrate
into the smaller lens substrates comprises making a single cut
between a pair of adjacent lenses to separate the lenses from one
another and substantially remove overflow regions between the pair
of adjacent lenses.
4. The method of claim 1, wherein separating the lens substrate
into the smaller lens substrates comprises making a first cut
between a pair of adjacent lenses to separate the lenses from one
another and substantially remove an overflow region for a first
lens of the pair and making a second cut to substantially remove an
overflow region for a second lens of the pair.
5. The method of claim 1, wherein substantially removing the
overflow regions includes removing at least 60% of the overflow
regions.
6. The method of claim 5, wherein substantially removing the
overflow regions includes removing at least 80% of the overflow
regions.
7. The method of claim 1, wherein separating the lens substrate
into the smaller lens substrates comprises separating the lens
substrate into smaller lens substrates having lateral areas that
are less than 1.2 millimeters by 1.2 millimeters.
8. The method of claim 7, wherein the lateral areas are less than
0.9 millimeters by 0.9 millimeters.
9. A method comprising: providing a lens substrate having an array
of lenses, the lens substrate including an overflow region next to
each lens of the array, each overflow region including an overflow
lens material; providing an image sensor array substrate having an
array of image sensor arrays; bonding the lenses with the image
sensor array substrate; and performing one or more sets of dicing
operations to dice the lens substrate and the image sensor array
substrate into individual modules each having an image sensor array
and one of a single lens and a plurality of stacked lenses, wherein
performing the one or more sets of dicing operations includes
substantially removing the overflow regions.
10. The method of claim 9, wherein said bonding and said performing
the one or more sets of dicing operations comprises: wafer bonding
the lens substrate having the array of lenses and the image sensor
array substrate; and dicing the bonded lens and image sensor array
substrates into the individual modules, wherein the dicing
substantially removes the overflow regions.
11. The method of claim 9, wherein said bonding and said performing
the one or more sets of dicing operations comprises: dicing the
lens substrate having the array of lenses into individual lens die
each having one of a single lens and a plurality of stacked lenses;
bonding each lens die to a corresponding image sensor array of the
image sensor array substrate; and dicing the image sensor array
substrate having the lens die bonded thereto into the individual
modules.
12. The method of claim 11, wherein dicing the lens substrate
substantially removes the overflow regions.
13. The method of claim 9, wherein performing the one or more sets
of dicing operations to dice the lens substrate and the image
sensor array substrate into the individual modules comprises dicing
into individual modules having lateral areas that are less than 1.2
millimeters by 1.2 millimeters.
14. The method of claim 9, wherein providing the image sensor array
substrate comprises providing an image sensor array substrate
having one or more through-silicon vias.
15. A miniature camera module, the miniature camera module
comprising: an aperture operable to receive light from an external
environment; one of a single lens and a plurality of stacked lenses
optically coupled to receive the light from the aperture, the one
of the single lens and the plurality of stacked lenses operable to
optically focus the light; an image sensor array optically coupled
to receive the focused light from the one of the single lens and
the plurality of stacked lenses, the image sensor array having a
lateral area that is less than 0.6 millimeters by 0.6 millimeters,
and the miniature camera module having a lateral area that is less
than 1.2 millimeters by 1.2 millimeters; and interconnects
electrically coupled with the image sensor array and accessible
from an outside of the miniature camera module to allow electrical
connection to be made to an external signaling medium, wherein the
one of the single lens and the plurality of stacked lenses is
operable to optically focus the light on the active area of the
image sensor array to provide a working distance that is less than
50 millimeters and a field of view that is greater than
70.degree..
16. The miniature camera module of claim 15, wherein the one of the
single lens and the plurality of stacked lenses has no more than
three focusing surfaces.
17. The miniature camera module of claim 16, wherein the one of the
single lens and the plurality of stacked lenses has only two
focusing surfaces.
18. The miniature camera module of claim 15, wherein the one of the
single lens and the plurality of stacked lenses has a lateral area
of less than 0.9 millimeters by 0.9 millimeters, and wherein the
image sensor array has a lateral area that of less than 0.5
millimeters by 0.5 millimeters.
19. The miniature camera module of claim 15, wherein the working
distance is less than 30 millimeters and the field of view is
greater than 75.degree..
20. The miniature camera module of claim 15, wherein the one of the
single lens and the plurality of stacked lenses comprises one or
more molded lens, and wherein the one of the single lens and the
plurality of stacked lenses has a surface where an overflow region
has been cut away.
21. The miniature camera module of claim 15, wherein the
interconnects comprise a ball grid array.
22. The miniature camera module of claim 15, wherein the one of the
single lens and the plurality of stacked lenses includes a first
lens closest to the aperture stop and a second lens, and wherein
the aperture stop is at the first lens.
23. The miniature camera module of claim 15, wherein the one of the
single lens and the plurality of stacked lenses includes a molded
lens of a polymeric material capable of withstanding a solder
reflow process without compromised optical properties.
24. The miniature camera module of claim 15, wherein the one of the
single lens and the plurality of stacked lenses comprises only two
lenses providing only two optical focusing surfaces, wherein the
lateral area of the image sensor array is no more than 0.4
millimeters by 0.4 millimeters, wherein the lateral area of the
miniature camera module is no more than 0.8 millimeters by 0.8
millimeters, wherein the working distance is less than 30
millimeters, and wherein the field of view is greater than
75.degree..
25. An endoscope comprising a housing and the miniature camera
module of claim 15 enclosed within the housing.
26. A miniature camera module, the miniature camera module
comprising: an aperture operable to receive light from an external
environment; one of a single lens and a plurality of stacked lenses
optically coupled to receive the light from the aperture, the one
of the single lens and the plurality of stacked lenses operable to
optically focus the light, the one of the single lens and the
plurality of stacked lenses having a lateral area that is less than
1.2 millimeters by 1.2 millimeters, the one of the single lens and
the plurality of stacked lenses including one or more molded lens,
and the one of the single lens and the plurality of stacked lenses
having a surface where an overflow lens material has been cut away;
an image sensor array optically coupled to receive the focused
light from the one of the single lens and the plurality of stacked
lenses, the image sensor array having a lateral area that is less
than 0.6 millimeters by 0.6 millimeters; and interconnects
electrically coupled with the image sensor array and accessible
from an outside of the miniature camera module to allow electrical
connection to be made to an external signaling medium.
27. The miniature camera module of claim 26, wherein the one of the
single lens and the plurality of stacked lenses has no more than
three focusing surfaces.
28. The miniature camera module of claim 26, wherein the one of the
single lens and the plurality of stacked lenses has a lateral area
of less than 0.9 millimeters by 0.9 millimeters, and wherein the
image sensor array has a lateral area that of less than 0.5
millimeters by 0.5 millimeters.
29. The miniature camera module of claim 26, wherein the one of the
single lens and the plurality of stacked lenses comprises only two
lenses providing only two optical focusing surfaces, wherein the
lateral area of the image sensor array is no more than 0.4
millimeters by 0.4 millimeters, wherein the lateral area of the one
of the single lens and the plurality of stacked lenses is no more
than 0.8 millimeters by 0.8 millimeters, wherein a working distance
of the miniature camera module is less than 30 millimeters, and
wherein a field of view of the miniature camera module is greater
than 75.degree..
30. An endoscope comprising: a hermetically sealed housing, the
housing having a transparent portion; a light source enclosed
within the hermetically sealed housing, the light source positioned
to transmit light through the transparent portion of the housing; a
miniature wafer-level camera module enclosed within the
hermetically sealed housing, the miniature camera module positioned
to receive light through the transparent portion of the
hermetically sealed housing, the miniature camera module including:
an aperture operable to receive the light received through the
transparent portion; one of the single lens and the plurality of
stacked lenses optically coupled to receive the light from the
aperture, the one of the single lens and the plurality of stacked
lenses operable to optically focus the light; an image sensor array
optically coupled to receive the focused light from the one of the
single lens and the plurality of stacked lenses, the image sensor
array having a lateral area that is less than 0.6 millimeters by
0.6 millimeters, and the miniature camera module having a lateral
area that is less than 1.2 millimeters by 1.2 millimeters; and
interconnects electrically coupled with the image sensor array and
accessible from an outside of the miniature camera module to allow
electrical connection to be made to an external signaling medium,
wherein the one of the single lens and the plurality of stacked
lenses is operable to optically focus the light on the active area
of the image sensor array to provide a working distance that is
less than 50 millimeters and a field of view that is greater than
75.degree.
31. The endoscope of claim 30, wherein the one of the single lens
and the plurality of stacked lenses comprises one or more molded
lens, and wherein the one of the single lens and the plurality of
stacked lenses has a surface where an overflow region has been cut
away.
32. The endoscope of claim 30, wherein the one of the single lens
and the plurality of stacked lenses has no more than three focusing
surfaces.
33. The endoscope of claim 30, wherein the lateral area of the
image sensor array is no more than 0.5 millimeters by 0.5
millimeters, and wherein the lateral area of the one of the single
lens and the plurality of stacked lenses is no more than 0.9
millimeters by 0.9 millimeters.
34. The endoscope of claim 30, wherein the endoscope comprises a
capsular endoscope, and wherein the hermetically sealed housing has
a size and a shape capable of being swallowed by a human.
35. The endoscope of claim 30, further comprising a flexible
cannula having a proximal portion and a distal portion to be
introduced into a patient, and wherein the hermetically sealed
housing is located at the distal portion of the flexible cannula.
Description
BACKGROUND
[0001] 1. Field
[0002] Embodiments of the invention pertain to camera modules or to
methods of manufacturing camera modules. In particular, embodiments
of the invention pertain to miniature wafer-level camera modules or
to methods of manufacturing miniature wafer-level camera
modules.
[0003] 2. Background Information
[0004] A representative manufacturing process for conventional
camera modules may include manufacturing individual lenses one at a
time or in small groups, but not through a wafer-level
manufacturing process. In conventional camera modules, the
individual lenses are assembled and attached to individual image
sensor arrays. For example, one or more individual lenses may be
assembled with a lens barrel or other lens holder, the lens barrel
or holder may be assembled with a lens mount, and the lens mount
may be mounted on a printed circuit board or flex substrate on
which the individual image sensor array has been mounted. Other
individual components such as filters, readout electronics, and the
like, may similarly be individually assembled together to form the
conventional camera module. This manufacturing process has certain
drawbacks for certain implementations. In particular, the
manufacturing process used for conventional camera modules tends to
impose certain limits on the size and/or manufacturing cost
achievable for these conventional camera modules. Moreover,
conventional manufacturing processes are not able to benefit from
the economies of scale and potential cost savings associated with
wafer-level manufacturing processes.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0005] The invention may best be understood by referring to the
following description and accompanying drawings that are used to
illustrate embodiments of the invention. In the drawings:
[0006] FIG. 1 is a block flow diagram of an example embodiment of a
method of separating a lens wafer or other lens substrate having an
array of lenses into multiple lens dice or other smaller lens
substrates that each have a single lens or stack of two or more
lenses.
[0007] FIGS. 2A-C are schematic cross-sectional views illustrating
an example embodiment of a method of making a lens wafer or other
larger lens substrate having an array of lenses by molding with a
lens molding master, and separating the lens wafer or other larger
lens substrate into multiple lens dice or other smaller lens
substrates.
[0008] FIG. 3 is a top view of a lens wafer having an array of
lenses.
[0009] FIG. 4 is a block flow diagram of an example embodiment of a
method of manufacturing image sensor array-lens modules for
wafer-level camera modules.
[0010] FIG. 5 is a block flow diagram of a first example embodiment
of a method of bonding lenses with an image sensor array substrate
and performing one or more dicing operations to dice the lens
substrate and the image sensor array substrate.
[0011] FIG. 6 is a block flow diagram of a second example
embodiment of a method of bonding lenses with an image sensor array
substrate and performing one or more dicing operations to dice the
lens substrate and the image sensor array substrate.
[0012] FIG. 7 is a cross-sectional view of an example embodiment of
a miniature camera module.
[0013] FIG. 8 is a block diagram of an example embodiment of an
endoscope system including an endoscope and an endoscope base
station, where the endoscope has an embodiment of a miniature
camera module.
[0014] FIG. 9 is a block diagram of an example embodiment of a
capsule endoscope having an embodiment of a miniature camera
module.
DETAILED DESCRIPTION
[0015] In the following description, numerous specific details are
set forth. However, it is understood that embodiments of the
invention may be practiced without these specific details. In other
instances, well-known circuits, structures and techniques have not
been shown in detail in order not to obscure the understanding of
this description.
[0016] Wafer-level camera modules provide an alternative to
conventional camera modules and can be manufactured at sizes and/or
manufacturing costs below those typically achievable for
conventional camera modules. As the name suggests, wafer-level
camera modules may be manufactured by a process that incorporates
one or more wafer-level manufacturing operations. As in
conventional camera module manufacture, the image sensor arrays are
typically manufactured in parallel, at the wafer-level. However, in
contrast to conventional camera module manufacture, the lenses used
for wafer-level camera modules are also commonly manufactured at
the wafer-level. A lens wafer may be manufactured and may have an
array of individual lenses or an array of stacked lenses each
having two or more lenses. The stack of lenses are substantially
vertically aligned with one over the other(s) and as used herein
stacked may mean but does not necessarily mean that a lens is
stacked on top of a spacer (e.g., a stack of two lenses may include
a first lens on a first side of a substrate and a second lens on a
second, opposite side of the substrate.) By way of example, the
lens wafer may have a numerous lenses or stacks of lenses (e.g.,
from hundreds to many thousands). Similarly, other components like
filters, readout electronics, and the like, may potentially be
manufactured at the wafer-level. Moreover, whereas conventional
camera modules often have a plastic barrel to hold components
together, wafer-level camera modules may be diced after stacked.
Thus, wafer-level camera modules can be, and often are, more
compact than conventional camera modules. In applications where
compact size is advantageous, such as, for example, in various
different types of small form factor endoscopes, the compact size
of wafer-level camera modules provides a significant advantage.
Therefore, techniques capable of further improving the compactness
of wafer-level camera modules are advantageous and useful. In
addition, the wafer-level processing typically allows the
manufacturing costs of the wafer-level camera modules to be low,
which benefits disposable or limited-use applications and other
applications where low-cost miniature camera modules are
desirable.
[0017] FIG. 1 is a block flow diagram of an example embodiment of a
method 100 of separating a lens wafer or other lens substrate
having an array of lenses into multiple lens dice or other smaller
lens substrates that each have a single lens or stack of two or
more lenses. In some embodiments, the method may be performed as a
part of a method of making wafer-level camera modules. In other
embodiments the method may be performed separate from the
manufacture of wafer-level camera modules.
[0018] Initially, the lens wafer or other larger lens substrate may
be provided, at block 101. As used herein, providing a wafer or
other substrate is to be interpreted broadly to encompass making
the wafer or other substrate, buying, trading for, commissioning,
or otherwise acquiring the wafer or other substrate, or otherwise
obtaining the wafer or other substrate. The lens wafer or other
larger lens substrate has the array of lenses. As used herein the
term "array" encompasses, but does not necessarily imply, a
reticulated grid or row-and-column arrangement of lenses. Next to
each of the lenses of the array is a corresponding overflow region
of the substrate. Typically included within each of the overflow
regions is an overflow lens material, although some regions may
possibly omit an overflow lens material.
[0019] Referring again to FIG. 1, the lens wafer or other larger
lens substrate may be separated into multiple lens dice or other
smaller lens substrates at block 102. The separation may be
performed by dicing, singulation, sawing, cutting, or the like.
Each of the lens dice or other smaller lens substrates has a single
lens or stack of two or more lenses. In accordance with some
embodiments, the separation at block 102 may include removing or
substantially removing the overflow regions and/or overflow lens
material of the lens wafer or other larger lens substrate which are
next to each of the lenses of the array. As used herein,
"substantially removing" the overflow regions and/or overflow lens
material includes removing at least 60% of the overflow regions
and/or overflow lens material. As used herein, "removing" the
overflow regions and/or overflow lens material includes removing at
least 80% of the overflow regions and/or overflow lens material.
Other embodiments may remove at least 50%, at least 40%, at least
30%, or some other amount.
[0020] Advantageously, as will be explained further below, the
removal or substantial removal of the overflow regions and/or
overflow lens material may help to reduce the lateral area or
footprint of the lens dice, singulated lenses, or other smaller
lens substrates. While the scope of the invention is not limited to
making small lens die and/or wafer-level camera modules, one
potential advantage of removing or substantially removing the
overflow region and/or the overflow lens material is enhanced
ability to manufacture extremely small sized lenses and/or
wafer-level camera modules.
[0021] FIGS. 2A-C are schematic cross-sectional views illustrating
an example embodiment of a method of making a lens wafer or other
larger lens substrate 203 having an array of lenses 204-1, 204-2,
204-3 by molding with a lens molding master 205, and separating the
lens wafer or other larger lens substrate 203 into multiple lens
dice or other smaller lens substrates 206-1, 206-2, 206-3. In
accordance with some embodiments, separating the lens wafer or
other larger lens substrate into multiple lens dice or other
smaller lens substrates may include removing or substantially
removing overflow regions 207-1, 207-2, 207-3, 207-4 and/or
overflow lens material 208 of the lens wafer or other larger lens
substrate 203 which are next to and which correspond to each of the
lenses of the array.
[0022] FIG. 2A illustrates a first stage of the illustrated method
in which the lens molding master 205 is aligned above a substrate
209 with the liquid lens material 210 disposed between the lens
molding master and the substrate. In the illustrated embodiment,
the liquid lens material is disposed on the substrate. For example,
the liquid lens material may be dispensed, spread, deposited,
spin-coated, or otherwise applied or introduced onto the substrate.
Alternatively, in another embodiment, the liquid lens material may
be disposed on the lens molding master. For example, discrete
drops, beads, or other discrete portions of the liquid lens
material may be dispensed, deposited, applied, injected, or
otherwise introduced into the lens cavities 211-1, 211-2, 211-3 of
the lens molding master. The substrate 209 may be a glass
substrate, a transparent plastic substrate, another type of
optically transparent substrate, or another type of substrate
suitable for manufacturing the molded lens substrate 203. By way of
example, the liquid lens material 210 may be a thin layer of a
liquid polymerizable material having monomer reactants and/or
capable of undergoing polymerization reactions. Particular examples
of suitable liquid lens materials include, but are not limited to,
liquid epoxy materials, light or radiation curable monomer
containing optical materials, and other liquid lens materials
suitable for manufacturing molded lenses.
[0023] In various embodiments, the lens molding master 205 may be a
hard stamp (e.g., made of a glass or other hard or inflexible
material) or a soft stamp (e.g., made of polydimethylsiloxane
(PDMS), silicon rubber, or other soft, flexible, or rubbery
materials). The lens molding master has a lens molding surface 212
having an array of lens cavities 211-1, 211-2, 211-3 defined in the
lens molding master. Each of the lens cavities has a recessed
surface or structure having a shape of a lens intended to be molded
by the lens cavity (e.g., a concave, hemispherical, or other
lens-shaped surface). Around or potentially surrounding each of the
lens cavities are flat contact surfaces 213. The flat contact
surfaces are substantially coplanar with one another and are
designed to contact the substrate 209 when the lens molding master
205 is brought into contact with the substrate 209 and pressure is
applied. As shown, the region between the lens and the overflow
accumulation regions may be designed to be flat to allow spacers to
be seated on and bonded with the flat region. If desired, spacers
(not shown) may be stacked on this flat region, such as, for
example, to provide multiple layers of lenses. Defined in the lens
molding master, and aligned above respective ones of overflow
accumulation regions 207-1 through 207-4 to be discussed further
below, are overflow accumulation cavities 215-1, 215-2, 215-3,
215-4. Each of the overflow accumulation cavities has (in
cross-section) a rectangular, square, circular, irregular, or any
other suitable shape, and has a size sufficient to provide a recess
into which a portion of the liquid lens material may be forced,
displaced, or otherwise caused to overflow on the overflow
accumulation regions 207-1 through 207-4. In the illustrated
embodiment, relatively large sized overflow accumulation cavities
are shown, although the use of such large sized overflow
accumulation cavities is not required. The lens molding master may
be moved in the direction of the vertical downward arrows and
pressed against the substrate.
[0024] FIG. 2B illustrates a second stage of the method in which
the lens molding master 205 is pressed against the substrate 209
with the liquid lens material 210 disposed between the lens molding
master and the substrate. The flat contact surfaces 213 are pressed
substantially flat against the upper surface of the substrate
(e.g., very close to one another with a residual amount of liquid
lens material disposed between them). As the lens molding master is
pressed or forced against the substrate, the liquid lens material
flows and conforms to the shape of the molding surface 212 of the
lens molding master, as illustrated. The liquid lens material has
filled the array of lens cavities 211-1, 211-2, 211-3. The liquid
lens material may be cured or hardened while the lens molding
master remains in contact with the liquid lens material. In various
embodiments, depending upon the particular liquid lens material,
the curing or hardening of the liquid lens material may be achieved
through exposure to ultraviolet light or other actinic radiation,
through heating of the liquid lens material, or by allowing a
sufficient amount of time for hardening. Then, the lens molding
master may be separated from the substrate leaving an array of
individual hardened lenses on the substrate. The substrate having
the array of lenses represents a lens wafer or lens substrate
having an array of lenses fabricated at the wafer-level.
[0025] Typically, the manufacture of lens wafers by molding with a
lens molding master involves the application of excess liquid lens
material, in excess of that needed to just fill the lens cavities.
This excess helps to avoid incompletely filled lens cavities and/or
the formation of voids in the lenses and/or helps to improve the
formation of the lenses. As shown in the illustration, during the
molding operation the excess liquid lens material is forced,
displaced, or otherwise overflows into overflow accumulation
regions 207-1, 207-2, 207-3, 207-4 as overflow portions 208 of the
liquid lens material. Each of the overflow accumulation regions is
next to, and corresponds to, one of the lenses 204-1, 204-2, 204-3.
Notice that the excess liquid lens material has flow in the lateral
dimension, in the plane of the lens wafer, into these overflow
accumulation regions or yards. If the molded lens wafer were viewed
from above (i.e., a top view), the overflow accumulation regions
may partially or completely surround each of the corresponding
lenses with the corresponding lens toward the center of each of the
overflow accumulation regions. The overflow accumulation regions
are also occasionally know in the arts as "yards." Commonly, design
rules or heuristics prescribe that a size of an overflow
accumulation region or yard should be sufficient to be able to
accommodate a given percentage of the volume of the corresponding
lens. This percentage tends to vary inversely with the size of the
lens. Representatively, by way of example and not limitation, an
example design rule may prescribe that a lens for a miniature
wafer-level camera module have an associated overflow region that
is able to accommodate somewhere in the range of 10-40% of the
volume of the lens. Generally the smaller the lens, the greater the
percentage of the volume of the lens allocated for overflow. For
extremely small lenses, it is not uncommon for the overflow
accumulation region to be sized to accommodate around 30-40%, or
more, of the volume of the lens.
[0026] One potential drawback, depending upon the particular
implementation, is that the overflow portions and/or the overflow
accumulation regions tend to consume additional lateral area or
footprint on the lens wafer. For relatively larger camera modules,
since the area of the image sensor array tends to be sufficiently
small compared to the area of the camera module package, this
additional lateral area or footprint due to the overflow
accumulation regions may be acceptable. However, for relatively
smaller camera modules, for camera modules having high fill
factors, and for camera modules where the area of the image sensor
array is relatively high compared to the area of the camera module
package, this additional lateral area or footprint due to the
overflow accumulation regions may be undesirable. As used herein,
the fill factor represents the percentage of the image sensor array
lateral area to the camera module package lateral area. According
to conventional wafer-level camera module manufacture technologies,
if the area of the camera module package is not sufficient to
accommodate the area of the image sensor array plus the associated
overflow accumulation regions then the overflow volume design rule
tolerances may need to be reduced, which may reduce lens quality
and/or lens yields, or it may not otherwise be possible to form the
camera module package as small as desired utilizing this molding
with overflow approach. This limitation tends to be especially
problematic for extremely small wafer-level camera modules where
package sizes should be small and design rules prescribe relatively
larger overflow accumulation regions. Some embodiments of the
invention include removing or substantially removing an overflow
accumulation region and/or overflow lens material.
[0027] FIG. 2C illustrates a third stage of the illustrated method
in which the lens wafer or other larger lens substrate 203 is
separated into multiple lens dice or other smaller lens substrates
206-1, 206-2, 206-3. The separation may be performed by dicing,
singulation, sawing, cutting, or the like. Vertical dashed lines
216 delineate regions marked by "X" which may be removed or
discarded. As shown, in accordance with some embodiments, the
separation of the larger lens substrate into multiple lens dice or
other smaller lens substrates may include removing or substantially
removing the overflow regions and/or overflow lens material of the
lens wafer or other larger lens substrate which are next to each of
the lenses of the array. By enabling excess polymer to flow into
regions of the wafer that can then be diced away, high-fill factor
solutions can be achieved. The regions of the wafer having these
overflows of the excess lens material may simply be scrapped and do
not appear in the final module. This approach may also allow a
smaller footprint to be achieved than can be achieved for other
lens molding architectures such as a suspended lens architecture,
since overflow may occur outside of the final perimeters of the
device and be discarded.
[0028] In various embodiments, either one or multiple dicing cuts,
singulation cuts, saw cuts, or other cuts may be made between a
pair of adjacent lenses to separate the lenses and remove or
substantially remove the overflow regions and/or overflow lens
material. For example, in one embodiment, a single dicing cut may
both separate and remove or substantially remove the overflow
regions and/or overflow lens material between the pair of adjacent
lenses. The illustrated embodiment shows one example amount of the
overflow regions and/or overflow lens material that may be removed,
although other embodiments may remove either more or less of the
overflow regions and/or overflow lens material. For example, if a
smaller lens is desired, even more of the flat regions
corresponding to the flat contact surfaces 213 may optionally be
removed. In addition, in the illustrated embodiment, each of the
lens dice or other smaller lens substrates has a single lens,
although in other embodiments each may have a stack of two or more
lenses. In one aspect, each of the lenses may be molded similarly
to the lenses 204-1, 204-2, 204-3 in additional molding operations.
Methods of forming stacked lenses by molding are known in the arts.
In one aspect, different architectures, such as, for example, a
layered lens architecture, a hybrid architecture involving a lens
similar to that discussed above in combination with a lens having a
lens-in-a-pocket architecture, or other architectures.
[0029] Advantageously, the removal or substantial removal of the
overflow regions and/or overflow lens material may help to reduce
the lateral area or footprint of the lens dice, singulated lenses,
or other smaller lens substrates. While the scope of the invention
is not limited to making small lens die and/or wafer-level camera
modules, one potential advantage of removing or substantially
removing the overflow region and/or the overflow lens material is
enhanced ability to manufacture extremely small sized lenses and/or
wafer-level camera modules. The scope of other embodiments is not
limited to making lenses of any particular size.
[0030] FIG. 3 is a top view of a lens wafer 303 having an array of
lenses 304. In the illustration, nine lenses are shown on the lens
wafer, although commonly many more lenses may be included on a lens
wafer. Around and surrounding each of the lenses are an example
embodiment of overflow regions or yards 307. The illustrated
overflow regions or yards are defined between inner squares
representing inner perimeters and outer squares representing outer
perimeters, where a single corresponding lens is approximately
centered within each of the inner and outer squares. It is to be
appreciated that other than square yards are also suitable (e.g.,
rectangular, circular, oval, etc.). An example embodiment of dicing
lines 316 representing where dicing cuts may be made to separate
the lens wafer into lens dice is shown. In the illustrated
embodiment, two dicing lines are used between each pair of adjacent
lenses to separate the lenses and remove or substantially remove
the overflow regions/yards and/or any overflow lens material that
would flow into the overflow accumulation regions/yards.
Alternatively, a single much wider cut may be used between each
pair of adjacent lenses to both separate the lenses and remove or
substantially remove the overflow regions/yards and/or any overflow
lens material.
[0031] Commonly, at least some of the assembly of wafer-level
camera modules is also performed at the wafer-level. In one
approach, the image sensor array wafer and the lens wafer may be
aligned such that each image sensor array and each corresponding
set of one or more lenses are aligned relative to one another, and
then wafer bonded together. Then, the bonded wafers may be diced,
singulated, or otherwise separated into wafer-level camera modules
each having an image sensor array and one or more corresponding
lenses. In this first approach, the lenses and image sensor arrays
are bonded or combined at the wafer-level. In another approach, the
lens wafer may first be diced, singulated, or separated into lens
dice each having one lens or a stack of lenses. Each of these lens
dice may be aligned and bonded with a corresponding image sensor
array of the image sensor array wafer. Then, the image sensor array
wafer having the lens dice bonded thereto may be diced, singulated,
or otherwise separated into wafer-level camera modules each having
an image sensor array and one or more corresponding lenses. Dicing
the lens wafer before dicing the image sensor array wafer may offer
an advantage when the yield of acceptable lenses is greater than
the yield of acceptable image sensor arrays, for example.
[0032] FIG. 4 is a block flow diagram of an example embodiment of a
method 420 of manufacturing image sensor array-lens modules for
wafer-level camera modules. A lens wafer or other substrate having
an array of lenses is provided, at block 421. The lens substrate
has an overflow accumulation region next to each lens of the array.
For example, each overflow accumulation region may at least
partially or completely surround a corresponding lens. Each
overflow accumulation region has an overflow portion of lens
material. An image sensor array wafer or other substrate having an
array of image sensor arrays is also provided, at block 421. In
some embodiments, the image sensor array wafer may use
through-silicon vias or through-sensor vias (TSVs). A TSV is a via
or other vertical electrical interconnect that passes completely
through a silicon wafer or die or image sensor array wafer or die.
The TSVs may allow for electric connections between sensor pads and
a ball grid array without having to dice the sensors, although this
is not required. As before, providing these wafers or substrates
may include making, buying, or otherwise obtaining these wafers or
substrates. The lenses are bonded with the image sensor array
substrate, at block 423. Different ways in which this may be done
will be discussed further below in conjunction with FIGS. 5-6. One
or more dicing operations are performed to dice the lens substrate
and the image sensor array substrate into individual image sensor
array-lens modules, at block 424. Each image sensor array-lens
module has an image sensor array and one or more corresponding
lenses. In some embodiments, performing the one or more dicing
operations includes removing or substantially removing the overflow
accumulation regions and/or overflow lens material.
[0033] The method of FIG. 4 encompasses different approaches for
bonding according to block 423 and dicing according to block 424.
FIG. 5-6 illustrate different approaches for bonding according to
block 423 and dicing according to block 424 that are encompassed by
the method of FIG. 4.
[0034] FIG. 5 is a block flow diagram of a first example embodiment
of a method 525 of bonding lenses with an image sensor array
substrate and performing one or more dicing operations to dice the
lens substrate and the image sensor array substrate. The lens
substrate having the array of lenses and the image sensor array
substrate having the array of image sensor arrays are aligned and
wafer bonded, at block 523. Individual lenses or lens stacks each
having two or more stacked lenses may be aligned and bonded over
corresponding individual image sensor arrays. Then, the bonded lens
and image sensor array substrates may be diced into individual
image sensor array-lens modules at the wafer-level, at block 524.
In some embodiments, the dicing of the bonded lens and image sensor
array substrates may include removing or substantially removing the
overflow accumulation regions and/or overflow lens material.
[0035] FIG. 6 is a block flow diagram of a second example
embodiment of a method 626 of bonding lenses with an image sensor
array substrate and performing one or more dicing operations to
dice the lens substrate and the image sensor array substrate. The
lens substrate having the array of lenses may be diced, singulated,
or separated into individual lens die, with each lens die having a
single lens or a lens stack having two or more stacked lenses, at
block 624-A. In one or more embodiments, the dicing, singulating,
or separating of the lens substrates at block 624-A includes
removing or substantially removing the overflow accumulation
regions and/or overflow lens material. Then, each lens die or
singulated set of one or more lenses may be aligned and bonded at
the die-level with a corresponding image sensor array of the image
sensor array substrate, at block 623. Then, the image sensor array
substrate having the lens die bonded thereto may be separately
diced, singulated, or separated into individual image sensor
array-lens modules, at block 624-B. In one or more embodiments, the
dicing, singulating, or separating of the image sensor array
substrate at block 624-B includes removing or substantially
removing the overflow accumulation regions and/or overflow lens
material. In still other embodiments, the removal or the
substantial removal of the overflow accumulation regions and/or
overflow lens material is performed partially at block 624-A and
partially at block 624-B.
[0036] FIG. 7 is a cross-sectional view of an example embodiment of
a miniature camera module 750. In various embodiments, the camera
module may have a maximum lateral area or cross section (which as
viewed is a horizontal plane into the page), which has a size that
is less than 1.3 mm.times.1.3 mm, or less than 1.2 mm.times.1.2 mm,
or less than 1.1 mm.times.1.1 mm, or less than 1.0 mm.times.1.0 mm,
or less than 0.9 mm.times.0.9 mm, or less than 0.8 mm.times.0.8 mm,
or less than 0.25 mm.times.0.25 mm.
[0037] The miniature camera module has an aperture 751. During
operation, the aperture 751 is operable to receive light from an
external environment surrounding the miniature camera module. The
aperture represents a region through which light is able to enter
the miniature camera module and helps to determine the angle of
light rays received into the camera module that are to be focused
onto an image sensor array 752. If the miniature camera module were
viewed from above, the aperture 751 of one embodiment may represent
a generally circular opening, or optically transparent region,
within a surrounding optically non-transparent layer, coating, or
material (not shown) formed over a top surface 757 of a first glass
or other transparent substrate 753 and over a top surface 758 of a
glass or other protective mechanical spacer 754. By way of example,
the non-transparent layer, coating, or material may be a black
material (e.g., a black yard mask), a reflective material (e.g., a
metal layer), or other non-optically transparent materials capable
of blocking incident light. Light from the external environment may
only enter the miniature camera module through the aperture
751.
[0038] The miniature camera module has either a single lens or two
more more stacked lenses 755, 766. The single lens or the stack of
the two or more lenses is optically coupled to receive the light
from the aperture 751. The single lens or the stack of the two or
more lenses is operable to optically focus the received light. In
various embodiments, the camera module may have no more than four,
no more than three, or only two focusing surfaces. The focusing
surfaces may represent curved surfaces of one or more lenses that
are capable of focusing light. Having fewer focusing surfaces tends
to reduce the size and/or manufacturing costs.
[0039] The illustrated embodiment of the miniature camera module
includes a stack of a first, smaller lens 755 on the top surface
757 of the first glass or other transparent substrate 753. The
first, smaller lens 755 is included within an opening 760 in the
glass or other protective mechanical spacer 754. The opening 760
may be laser drilled, mechanically drilled, etched, or otherwise
formed in the spacer 754 and the spacer 754 may be coupled with the
glass substrate or other transparent substrate 753 either at the
wafer or die level. The first, smaller lens 755 is disposed over
the aperture 751 and is substantially coextensive in lateral area
with the aperture 751. The first, smaller lens has a flat, lower
surface abutting the first glass or other transparent substrate
753, which is substantially aligned with and coextensive with the
aperture 751. Around the flat, lower surface on the top surface 757
of the first glass or other transparent substrate 753 is the black
yard mask, metal, or other non-optically transparent material to
block light. Representatively, the black, metal, or other
non-optically transparent material may be deposited, coated, or
otherwise formed over the first glass or other transparent
substrate 753 prior to molding the first, smaller lens 755 on the
substrate 753. A top surface of the first, smaller lens 755 is
curved and represents a first focusing surface. The first, smaller
lens may receive light through the aperture and focus the received
light.
[0040] The lens stack of the illustrated embodiment also includes a
second, larger lens 756 on a bottom surface 759 of the first glass
or other transparent substrate 753. The second, larger lens is
included within an opening 761 in a second glass or other
mechanical spacer 762. The opening 761 may be laser drilled,
mechanically drilled, etched, or otherwise formed in the spacer 762
and the spacer 762 may be coupled with the glass substrate or other
transparent substrate 753 either at the wafer or die level. The
second, larger lens 756 is optically coupled to receive focused
light from the first, smaller lens 755. The first lens 755 and the
second lens 756 are substantially vertically aligned with one
another. The second, larger lens 756 may be a landscape lens or a
simple meniscus singlet having an upper, flat surface adjacent the
lower surface 759 of the first glass or other transparent substrate
753. If desired, an infrared filter layer (not shown) may
optionally be formed on the lower surface 759 of the first glass or
other transparent substrate 756 prior to molding the second, larger
lens thereto. The second, larger lens also has a lower, curved
surface which may be a substantially steep convex surface. The
lower, curved surface of the second, larger lens represents a
second focusing surface. In some embodiments, one or more of the
first and second lenses may be aspherical lenses operable to
provide higher order aspherical components, and thus a combination
of higher image quality or larger field of view (FOV).
[0041] In some embodiments the stack of the one or more lenses 755,
756 may be formed at the wafer-level using either a lens molding
approach or a direct etching approach. Forming the lenses at the
wafer-level and potentially using wafer-level processing tends to
reduce the manufacturing costs. In the case of direct etching, a
resist or other sacrificial material may first be patterned onto a
substrate and then reflowed to form hemispherical or lens shapes.
The wafers may then be plasma etched or otherwise etched to
transfer the hemispherical or lens shapes of the sacrificial
material into the underlying substrate. In the case of a lens
molding approach, in some embodiments, a lens molding method
similar to those discussed above may optionally be used, and when
separating the lens wafer or other larger lens substrate into lens
dice or other smaller lens substrates each having the stack of the
one or more lenses, overflow regions or yards may be removed or
substantially removed, as previously described. In the case of
these embodiments, right and left (as viewed) vertical sidewall
surfaces 763, 764 may represent diced, sawed, or cut surfaces where
overflow regions and/or overflow materials have been diced, cut, or
severed away. As another option, other lens architectures, such as,
for example, a suspended lens architecture, a lens-in-a-pocket
architecture, a hybrid architecture, or other architectures capable
of providing miniature lenses, may optionally be used. In one
embodiment, the lenses may be molded of an Ormocomp brand
ultraviolet (UV) curable hybrid polymeric material. One advantage
of Ormocomp brand polymeric material is that it is capable of
withstanding solder reflow temperatures and/or solder reflow
processes without compromising the optical performance of the
lenses. Other polymeric lens materials known in the art to be
capable of withstanding solder reflow temperatures and/or solder
reflow processes may also optionally be used.
[0042] Referring again to FIG. 7, the miniature camera module has
an image sensor array die 765 having an image sensor array 752. The
image sensor array 752 is optically coupled to receive the focused
light from the stack of the one or more lenses 755, 756. An image
sensor cover glass or other glass or transparent substrate 766 is
optically coupled between the second, larger lens 756 and the image
sensor array die 765. A so-called dam region 767 is coupled between
the image sensor cover glass or other glass or transparent
substrate 766 and the image sensor array die 765 and may provide
air, atmosphere, or an inert gas (e.g., nitrogen gas) above the
image sensor array. The image sensor array 752 is an active area of
the die that is operable to sense light and produce electrical
signals for imaging. In some embodiments, a lateral area of the
image sensor array, which as viewed is a horizontal plane into the
page, is less than 0.6 mm by 0.6 mm, less than 0.5 mm by 0.5 mm, or
less than 0.4 mm by 0.4 mm. In one particular example embodiment,
the image sensor array is an array of about 200.times.200 pixels,
each pixel has about 1.75 micrometer pixel pitch with an active
area diagonal of about 0.5 mm, and the image sensor array has a
lateral area of about 0.35 mm.times.0.35 mm, although the scope of
the invention is not so limited. Around the image sensor array is a
peripheral region including circuitry. The image sensor array may
be a complementary metal oxide semiconductor (CMOS) image sensory
array, which may be either front side illuminated (FSI) or back
side illuminated (BSI).
[0043] In some embodiments, the stack of the one or more lenses is
operable to optically focus the light on the active area of the
image sensor array to provide a working distance that is less than
50 millimeters (mm), less than 30 mm, less than 20 mm, or less than
15 mm, and often greater than about 5 mm. In some embodiments, the
stack of the one or more lenses is operable to optically focus the
light on the active area of the image sensor array to provide a
field of view (FOV) of at least 70.degree., at least 75.degree., at
least 80.degree., between about 75-85.degree., or an even greater
field of view. In some cases, the working distance may be less than
20 millimeters and the field of view may be greater than
70.degree., and in certain cases the working distance may be less
than 15 millimeters and the field of view may be greater than
75.degree.. For small sized image sensor arrays, as few as two
focusing surfaces may be operable to provide sufficient image
quality at these fields of view and working distances. In some
aspects, the two focusing surfaces may be provided by only one or
only two lenses. Such a small number of lenses is advantageous in
terms of cost and small form factor. Conventional non-wafer-level
techniques of manufacturing lenses are typically not able to
manufacture such small form factor lenses. Additionally, larger
lenses manufactured by these conventional, non-wafer-level
techniques are typically used with larger image sensors having
larger image areas. This is not only disadvantageous from the point
of view of form factor, but also because, due to the larger image
area, six or more lenses are often needed to achieve equivalent
image quality at similar ranges of working distances and field of
view. Using six or more lenses tends to significantly increase the
manufacturing cost.
[0044] The miniature camera module has interconnects 766 on an
outside of the camera module housing to allow connection to an
external signaling medium. As shown, in some embodiments the
interconnects may include a ball grid array. In some embodiments,
the miniature camera module may be a surface mount capable device
that is capable of being surface mounted to an external signaling
medium (e.g., a printed circuit board or flex substrate) for
example with wire bonding or flip-chip techniques. Using such ball
grid array for interconnection may help to reduce the size and
manufacturing costs compared to those typically achievable if
input/output pins and through-hole interconnection technologies
were employed. Another option would be to use through silicon via
technology.
[0045] The miniature lenses and/or miniature camera modules
disclosed elsewhere herein may be used in a variety of different
applications where there is a benefit to having miniature lenses
and/or miniature camera modules. Examples of applications include,
but are not limited to, mobile phones, laptop cameras, notebook
webcams, surveillance devices, automotive camera applications, and
medical imaging applications. To further illustrate certain
concepts, further details of a medical imaging application in an
endoscope will be described, although the scope of other
embodiments are not limited to endoscopes.
[0046] Endoscopes are commonly used for medical imaging
applications. Endoscopes are instruments or devices that may be
inserted into a patient (human or animal) and used to look inside a
body cavity, lumen, or otherwise look inside the patient. Various
different types of endoscopes need to have a small lateral
form-factor. For example, capsule endoscopes or pill endoscopes
need to have a small lateral form factor so that they can be
swallowed easily and without discomfort or risk of choking. As
another example, various other different types of small form-factor
endoscopes designed to be inserted into small body cavities,
lumens, orifices, and the like, which should also be small so as to
provide better maneuverability, fit in smaller spaces, and/or
reduce patient discomfort.
[0047] Such small lateral form-factor endoscopes may benefit from
small image sensors arrays. The image sensor arrays should provide
sufficient image quality for the intended application and a
sufficiently large field of view. Commonly, in endoscopes the field
of view should be typically greater than 70.degree., often greater
than 75.degree., and in many cases at least about 80.degree.. To
achieve the desired image quality and field of view, previously
proposed camera modules for endoscopes included four or more
lenses, which tends to increase the cost of manufacture of the
camera modules. However, various embodiments of small wafer-level
camera modules as disclosed elsewhere herein (e.g., the camera
module 750 of FIG. 7) are able to achieve sufficient image quality
and a sufficiently large field of view (e.g., greater than
70.degree., 75.degree., or 80.degree.). In some embodiments,
wafer-level optics, and substantially removing or removing overflow
regions as disclosed herein, may be used to make the extremely
small wafer-level camera modules. As a result, these miniature
camera modules are useful in endoscopes. In some embodiments, these
miniature camera modules achieve the field of view and image
quality with only two lenses, which helps to keep the manufacturing
costs low. Moreover, when lenses are manufactured at the wafer
level, the typically large gross die per wafer (GDPW) counts
resulting from the wafer-level optics also helps to reduce the
manufacturing costs. These reduced manufacturing costs may offer a
significant advantage when the camera modules are incorporated into
disposable or limited use endoscopes, as well as in other
applications where reducing the costs of the camera modules is
highly advantageous.
[0048] FIG. 8 is a block diagram of an example embodiment of an
endoscope system 870 including an endoscope 871 having a miniature
camera module 850. Examples of suitable types of endoscopes
include, but are not limited to, bronchoscopes, colonoscopes,
gastroscopes, duodenoscopes, sigmoidoscopes, thorascopes,
ureteroscopes, sinuscopes, boroscopes, and thorascopes, to name
just a few examples.
[0049] The endoscope system includes an endoscope base station 872
and the endoscope 871. The endoscope is connected to a connector
interface 873 of the endoscope base station. In particular, a
proximal portion of the endoscope has a connector 874 at an end of
a cable 875. The connector 874 is connected to the connector
interface 873. The connector may also be disconnected from the
connector interface when the endoscope is not in use. The endoscope
and the endoscope base station may be manufactured and sold
separately, potentially by different vendors.
[0050] Attached to a distal end of the cable 875 is a handle and
control device 876. The handle and control device may provide a
handle that an operator of the endoscope may use to hold and
maneuver the endoscope. The handle and control device may have
varying levels of controls that the operator of the endoscope may
use to control movement and functioning of the endoscope. A few
representative examples include, but are not limited to,
controlling movement of the endoscope, controlling lighting,
controlling image acquisition, and controlling thereapeutic
functionalities of the endoscope (e.g., controlling a cutting
device, deploying a balloon, etc.).
[0051] A distal portion 877 of the endoscope is coupled with the
handle and control device 876. In some embodiments, the distal
portion 877 may include a flexible cannula. In some embodiments,
the distal portion 877 may be attachable and detachable to the
handle and control device 876. In some embodiments, the endoscope
871 and/or the distal portion 877 may be a one-time use, limited
use, or disposable endoscope and/or the distal portion. Embodiments
of wafer-level camera modules disclosed herein, which may be
manufactured at relatively low manufacturing costs due in part to
the wafer-level processing and/or the surface mount
interconnections, may be well suited for such one-time use, limited
use, or disposable endoscopes.
[0052] At least a distal tip of the distal portion 877 is intended
to be introduced into a body of a patient. For example, the distal
tip of the distal portion may be introduced into a nose, ear,
mouth, rectum, esophagus, vein, artery, or other body cavity or
lumen. The distal tip of the distal portion may have a hermetically
sealed housing having a transparent glass or transparent plastic
window, lens, or other transparent portion. A light source may be
enclosed within the hermetically sealed housing. The light source
may be positioned to transmit light through the transparent portion
of the housing. A miniature camera module 850 may also be coupled
with the distal portion 877 of the endoscope. The miniature camera
module 850 may be enclosed within the hermetically sealed housing.
The miniature camera module positioned to receive light through the
transparent portion of the hermetically sealed housing. The
miniature camera module may be used to view or acquire images of a
surface of interest 878 (e.g., a surface or feature inside a
patients body).
[0053] The miniature camera module 850 may have any of the features
of the miniature camera modules or miniature lenses disclosed
elsewhere herein. For example, in various embodiments, the
miniature camera module 850 may have a lens die or lens substrate
made in accordance with the method of FIG. 1, the miniature camera
module may be made in accordance with the method of FIG. 4, and/or
the miniature camera module may have features of the miniature
camera module of FIG. 7. Typically, in endoscope applications, the
miniature camera modules may have a working distance that is less
than 50 millimeters (mm), less than 30 mm, less than 20 mm, or less
than 15 mm, and often greater than about 5 mm. Likewise, in
endoscope applications, the stack of the one or more lenses of the
miniature camera module may be operable to provide a field of view
(FOV) of at least 70.degree., at least 75.degree., at least
80.degree., between about 75-85.degree., or an even greater field
of view.
[0054] The miniature camera module 850 may offer certain potential
advantages when used with the endoscope 871 and/or distal portion
877. For one thing, the miniature camera module typically has a
small form factor as previously described. The small form factor of
the miniature camera module may be used in small sized endoscopes
that are capable of being introduced into small body cavities,
lumens, or regions and/or that may help to reduce patient
discomfort associated with larger sized endoscopes. For another
thing, the miniature camera modules typically can be manufactured
at relatively low costs, which may benefit use in disposable or
limited use endoscopes (as well as other disposable or limited use
devices).
[0055] The manufacturing cost of wafer-level manufacturing
techniques depends not only on gross die per wafer (GDPW) but also
on yields. To keep manufacturing costs low, it is desirable to have
high GDPW, which is easily achievable when the form factor of the
camera modules is small. For example, a sensor on the order of 1
mm.times.1 mm in an 8-inch wafer, for example, achieves a GDPW
value on the order of tens of thousands of sensors per wafer.
[0056] Yields, on the other hand, depend in part on the number of
process steps. Manufacturing processes having fewer steps tend to
have fewer failure points and accordingly tend to have higher
yields. Therefore, the manufacture of a camera module having only
two stacked lenses instead of three, four, six, or more stacked
lenses, offers manufacturing cost advantages not only because of
the reduced number of materials and labor required for their
manufacture, but also because of improved yields. The relative
importance of yield tends to become increasingly greater as the
GDPW increases.
[0057] FIG. 9 is a block diagram of an example embodiment of a
capsule endoscope 971. The capsule endoscope is also sometimes
known as a pill camera or pill cam. The capsule endoscope is to be
interpreted broadly as a device that is sized and shaped such that
it is capable of being swallowed and that includes a camera or
imaging device to allow images of an inside of a patient to be
acquired.
[0058] The capsule endoscope has a housing 980. The housing has a
size and a shape that are capable of being swallowed by a patient.
The term "capsule" is intended to cover any cylindrical, round,
rounded, generally capsule-like, or generally pill-like shape as
conventionally used for medicinal capsules or medicinal pills, or
shapes used for prior art capsule endoscopes known in the arts.
Commonly the housing is a hermetically sealed housing operable to
provide varying amounts of a hermetic seal to allow the device to
function as intended for the particular implementation.
[0059] The housing has a transparent portion 981 that is
transparent to light 983, 984 that is to be passed through the
transparent portion. By way of example, the transparent portion may
include a glass or plastic window or lens. In the illustrated
embodiment, the transparent portion comprises a transparent side,
or portion of a side, of the housing.
[0060] A light source 982 is enclosed within the housing. The light
source is positioned to transmit light 983 through the transparent
portion of the housing. The light source may include one or more
lights, such as, for example, various different types of light
emitting diodes (LEDs), lasers (e.g., vertical-cavity
surface-emitting lasers (VCSELs)), semiconductor lights, etc.
[0061] A miniature camera module 950 is also enclosed within the
housing. The miniature camera module is positioned to receive light
984 through the transparent portion of the housing. The miniature
camera module may have the features or characteristics of the
camera modules disclosed elsewhere herein.
[0062] Commonly, the capsule endoscope may also have a memory 985
enclosed within the housing to store images obtained by the camera
and optionally other data. Commonly, the capsule endoscope may also
have a controller 986 and power supply 987 enclosed within the
housing. The controller may control various different types of
operations performed by the capsule endoscope. The power supply may
provide power to the capsule endoscope. By way of example, the
power supply may include a battery. In some cases, the capsule
endoscope may have a data output port 988 operable to output images
stored in the memory. Alternatively, the data output port may
optionally be omitted, for example, if the device is a disposable
device that may be broken or dissembled to recover the memory. In
other cases the data output port may wirelessly transmit images and
data out of the capsule and/or outside the body of the patient. In
some cases, the capsule endoscope may have an optional image
processing unit 987.
[0063] The terms "coupled" and "connected," along with their
derivatives, may be used herein. It should be understood that these
terms are not intended as synonyms for each other. Rather, in
particular embodiments, "connected" may be used to indicate that
two or more elements are in direct physical or electrical contact
with each other. "Coupled" may mean that two or more elements are
in direct physical or electrical contact. However, "coupled" may
also mean that two or more elements are not in direct contact with
each other, but yet still co-operate or interact with each
other.
[0064] 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 of the invention. 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. The particular embodiments described are not provided to
limit the invention but to illustrate it. The scope of the
invention is not to be determined by the specific examples provided
above but only by the claims below. In other instances, well-known
circuits, structures, devices, and operations have been shown in
block diagram form or without detail in order to avoid obscuring
the understanding of the description.
[0065] It will also be appreciated, by one skilled in the art, that
modifications may be made to the embodiments disclosed herein, such
as, for example, to the sizes, shapes, configurations, forms,
functions, materials, and manner of operation, and assembly and
use, of the components of the embodiments. All equivalent
relationships to those illustrated in the drawings and described in
the specification are encompassed within embodiments of the
invention.
[0066] For simplicity and clarity of illustration, elements
illustrated in the figures have not necessarily been drawn to
scale. For example, the dimensions of some of the elements are
exaggerated relative to other elements for clarity. Further, 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.
[0067] Various operations and methods have been described. Some of
the methods have been described in a basic form in the flow
diagrams, but operations may optionally be added to and/or removed
from the methods. In addition, while the flow diagrams show a
particular order of the operations according to example
embodiments, it is to be understood that that particular order is
exemplary. Alternate embodiments may optionally perform the
operations in different order, combine certain operations, overlap
certain operations, etc. Many modifications and adaptations may be
made to the methods and are contemplated.
[0068] It should also be appreciated that reference throughout this
specification to "one embodiment", "an embodiment", or "one or more
embodiments", for example, means that a particular feature may be
included in the practice of the invention. Similarly, it should be
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. This method of
disclosure, however, is not to be interpreted as reflecting an
intention that the invention requires more features than are
expressly recited in each claim. Rather, as the following claims
reflect, inventive aspects may lie in less than all features of a
single disclosed embodiment. Thus, the claims following the
Detailed Description are hereby expressly incorporated into this
Detailed Description, with each claim standing on its own as a
separate embodiment of the invention.
* * * * *