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Digital Camera Patent Abstract
An exemplary lens module includes a lens barrel, a lens unit and
an aperture stop. The lens barrel includes a receiving part defining
a passage therein. The lens unit is made of glass. The aperture
stop is made from an iron-nickel based alloy having a thermal expansion
coefficient matching with that of glass. The lens unit and the aperture
stop are received in the passage of the receiving part in succession
order from an object side to an image side of the lens module. Digital
camera modules using such kind of lens modules are also provided.
Digital Camera Patent Claims
1. A lens module comprising: a lens barrel including a receiving
part defining a passage therein; a first lens unit made of glass;
and an aperture stop made from an iron-nickel based alloy having
a thermal expansion coefficient matching with that of glass, the
first lens unit and the aperture stop are received in the passage
of the receiving part in succession order from an object side to
an image side of the lens module.
2. The lens module of claim 1, wherein the iron-nickel based alloy
is selected from the group consisting of an invar alloy and a kovar
alloy.
3. The lens module of claim 2, wherein the invar alloy is selected
from the group consisting of a first composition composed of 62.51%
iron, 36% nickel, 0.25% chromium, 0.5% manganese, 0.25% silicon,
0.05% carbon, 0.1% aluminum, 0.1% magnesium, 0.1% zirconium, 0.1%
titanium, 0.02% phosphorus and 0.02% sulfur by weight, and a second
composition composed of 58.07.about.60.17% iron, 39.about.41.1%
nickel, 0.05% chromium, 0.6% manganese, 0.02% silicon, 0.05% carbon,
0.02% aluminum, 0.05% cobalt, 0.02% phosphorus and 0.02% sulfur
by weight.
4. The lens module of claim 2, wherein the kovar alloy is composed
of 52.about.53% iron, 29% nickel, 17% cobalt and 1.about.2% residual
composition by weight, the residual composition is selected from
the group consisting of magnesium, manganese, silicon, carbon, aluminum,
zirconium, titanium, phosphorus, sulfur and an mixture thereof.
5. The lens module of claim 1, further comprising a second lens
unit made of glass, wherein the second lens unit is received in
the passage and cooperates with the first lens to sandwich the aperture
stop therebetween.
6. The lens module of claim 5, further comprising a filter and
a spacer made from the iron-nickel based alloy, wherein the filter
is received in the passage and arranged closest to the image side,
the spacer is received in the passage and arranged between the second
lens unit and the filter.
7. The lens module of claim 6, wherein the iron-nickel based alloy
is selected from the group consisting of an invar alloy and a kovar
alloy.
8. The lens module of claim 7, wherein the invar alloy is selected
from the group consisting of a first composition composed of 62.51%
iron, 36% nickel, 0.25% chromium, 0.5% manganese, 0.25% silicon,
0.05% carbon, 0.1% aluminum, 0.1% magnesium, 0.1% zirconium, 0.1%
titanium, 0.02% phosphorus and 0.02% sulfur by weight, and a second
composition composed of 58.07.about.60.17% iron, 39.about.41.1%
nickel, 0.05% chromium, 0.6% manganese, 0.02% silicon, 0.05% carbon,
0.02% aluminum, 0.05% cobalt, 0.02% phosphorus and 0.02% sulfur
by weight.
9. The lens module of claim 7, wherein the kovar alloy is composed
of 52.about.53% iron, 29% nickel, 17% cobalt and 1.about.2% residual
composition by weight, the residual composition is selected from
the group consisting of magnesium, manganese, silicon, carbon, aluminum,
zirconium, titanium, phosphorus, sulfur and an mixture thereof.
10. The lens module of claim 1, wherein the lens barrel further
comprises a front part arranged closest to the object side, the
front part defines another cone-shaped passage therein with a diameter
decreasing along a direction from the object side to the image side,
and the another cone-shaped passage is in communication with the
passage of the receiving part.
11. A digital camera module comprising: a lens module, wherein
the lens module comprises a lens barrel including a receiving part
defining a passage therein, a first lens unit made of glass and
an aperture stop made from an iron-nickel based alloy having a thermal
expansion coefficient matching with that of glass, the first lens
and the aperture stop being received in the passage of the receiving
part in succession order from an object side to an image side; an
image sensor; and a holder defining an opening therein, the receiving
part of the lens barrel being engaged in the opening, the image
sensor being received in the opening and arranged at the image side.
12. The digital camera module of claim 11, wherein the iron-nickel
based alloy is selected from the group consisting of an invar alloy
and a kovar alloy.
13. The digital camera module of claim 11, the lens module further
comprises a second lens unit made of glass, wherein the second lens
unit is received in the passage and cooperates with the first lens
unit to sandwich the aperture stop therebetween.
14. The digital camera module of claim 13, the lens module further
comprises a filter and a spacer made from the iron-nickel based
alloy, wherein the filter and the spacer are received in the passage
and located between the second lens unit and the image sensor, the
filter is adjacent to the image sensor.
15. The digital camera module of claim 14, wherein the iron-nickel
based alloy is selected from the group consisting of an invar alloy
and a kovar alloy.
16. The digital camera module of claim 11, wherein the lens barrel
further comprises a front part arranged closest to the object side,
the front part defines an additional cone-shaped passage therein
with a diameter decreasing along a direction from the object side
to the image side, and the additional cone-shaped passage is in
communication with the passage of the receiving part.
17. The digital camera module of claim 11, further comprising a
base member receiving in the opening, the base member defines a
cavity in a surface thereof facing toward the aperture stop, and
the image sensor is received in the cavity.
18. The digital camera module of claim 17, further comprising a
cover, wherein the cover is received in the opening and arranged
on the base member configured for covering the image sensor.
19. A lens module comprising: a lens barrel defining a passage
therein; a lens unit made of glass; a spacer made from an iron-nickel
based alloy having a thermal expansion coefficient matching with
that of glass; and a filter including a base made of glass, the
lens unit, the spacer and the filter are received in the passage
in succession order from an object side to an image side of the
lens module.
20. The lens module of claim 19, wherein the iron-nickel based
alloy is selected from the group consisting of an invar alloy and
a kovar alloy.
Digital Camera Patent Description
BACKGROUND
[0001] 1. Technical Field
[0002] This invention relates generally to optical imaging apparatuses,
and more particularly to lens modules and digital camera modules
using the same.
[0003] 2. Related Art
[0004] Nowadays, digital camera modules are widely accepted for
their ease of use, digital image storage, immediate results and
image management potential, for example, employed in mobile phones.
Commonly, the digital camera modules work at various outdoor environments
having different temperatures and humidities, so the reliability
of working in the various environments to lens modules of the digital
camera modules is one of critical factors to achieve a high imaging
quality.
[0005] A typical lens module of a digital camera module includes
a lens barrel, and a first glass lens, an aperture stop, a second
glass lens, a spacer and an IR cut filter received in the lens barrel
in that order from an object side to an image side of the lens module.
Usually, the aperture stop and the spacer are made of either polymer
materials (e.g., carisoprodol) or dark-painted copper or brass.
However, the polymer materials and dark-painted copper or brass
are prone to generate thermal-induced deformations due to their
different thermal expansion coefficients comparing with glass. The
thermal-induced deformations of the aperture stop and/or spacer
may cause tilt, bending, and deformation on their neighboring lenses,
which will result in a deteriorated imaging quality of the digital
camera modules.
[0006] What is needed is to provide a lens module and a digital
camera module using the same having a better environment-tolerance.
SUMMARY
[0007] A preferred embodiment provides a lens module including:
a lens barrel, a lens unit and an aperture stop. The lens barrel
includes a receiving part defining a passage therein. The lens unit
is made of glass. The aperture stop is made from an iron-nickel
based alloy having a thermal expansion coefficient matching with
that of glass. The lens unit and the aperture stop are received
in the passage of the receiving part in succession order from an
object side to an image side of the lens module.
[0008] In another preferred embodiment, a digital camera module
includes a lens module as above described, an image sensor and a
holder. The holder defines an opening therein. The receiving part
of the lens barrel of the lens module as above described is engaged
in the opening. The image sensor is received in the opening and
arranged at the image side.
[0009] Other advantages and novel features will become more apparent
from the following detailed description of embodiments when taken
in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Many aspects of the present lens module and digital camera
module using the same can be better understood with reference to
the following drawings. The components in the drawings are not necessarily
to scale, the emphasis instead being placed upon clearly illustrating
the principles of the present lens module and digital camera module.
Moreover, in the drawings, like reference numerals designate corresponding
parts throughout the several views.
[0011] FIG. 1 is a schematic, cross-sectional view of a lens module
in accordance with a preferred embodiment; and
[0012] FIG. 2 is a schematic, cross-sectional view of a digital
camera module using the lens module of FIG. 1.
[0013] The exemplifications set out herein illustrate preferred
embodiments, in various forms, and such exemplifications are not
to be construed as limiting the scope of the present lens module
and digital camera module in any manner.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0014] Referring to FIG. 1, a lens module 100 in accordance with
a preferred embodiment of present invention is shown. The lens module
100 includes a lens barrel 10, lens units 22, 24, an aperture stop
30, a spacer 40 and a filter 50. The lens unit 22, aperture stop
30, lens unit 24, spacer 40 and filter 50 are received and fixed
in the lens barrel 10 in succession order from an object side to
an image side of the lens module 100.
[0015] The lens barrel 10 includes a receiving part 12 and a front
part 14. The receiving part 12 has a cylindrical shape and defines
a passage 122 therein. The receiving part 12 usually has an external
thread 124 on an outward circumference thereof. The passage 122
is configured for receiving the lens units 22, 24, aperture stop
30, spacer 40 and filter 50 therein. The front part 14 has a cone-shaped
passage 144 defined in a central portion thereof. A diameter of
the cone-shaped passage 144 gradually decreases along a direction
from the object side to the image side. The cone-shaped passage
144 is connected with the passage 122 of the receiving part 12.
Incident light beams passing through the cone-shaped passage 144
can reach into the passage 122 and incident on the lens units 22,
24 and the filter 50.
[0016] The lens units 22, 24 are usually made of glass and can
be aspherical lenses or spherical lenses. The lens unit 22 includes
a transparent central region 222 and a peripheral region 224 surrounding
the transparent central region 222. Likewise, the lens unit 24 includes
a transparent central region 242 and a peripheral region 244 surrounding
the transparent central region 242.
[0017] The aperture stop 30 usually is dark-painted annular sheet
which has a thickness in the range from 30 to 70 micrometers and
an inner diameter in the range from 0.3 to 0.8 micrometers. Preferably,
the annular sheet has a thickness in the range from 40 to 60 micrometers
and an inner diameter in the range from 0.4 to 0.6 micrometers.
[0018] The spacer 40 is configured for separating optical elements
such as lens unit 24 and filter 50, and for thereby forming a space
therebetween. The spacer 40 generally has a configuration matching
with the passage 122 and defines a passage 402 therein. The passage
402 usually has a cone shape having a diameter increasing along
the direction for the object side to the image side.
[0019] The aperture stop 30 and the spacer 40 are made from a material
having a thermal expansion coefficient matching with (i.e., similar
as) that of glass from which the lens units 22, 24 are made. This
characteristic of the material can beneficially prevent the neighboring
glass lens units 22, 24 of the aperture stop 30 and/or the spacer
40 from tilt, bending, and deformation when the lens module 100
working at various different environments. For example, the aperture
stop 30 and the spacer 40 are made from an iron-nickel based (FeNi-based)
alloy. The FeNi-based alloy may have a tensile strength of 67,000
pounds per square inch (psi) and can be used in a wide temperature
range from -40.degree. C. to 85.degree. C. and tolerate a relative
humidity in the range from 5% to 90%. In particular, in one embodiment,
the FeNi-based alloy is an invar alloy. The invar alloy can be composed
of 62.51% iron (Fe), 36% nickel (Ni), 0.25% chromium (Cr), 0.5%
manganese (Mn), 0.25% silicon (Si), 0.05% carbon (C), 0.1% aluminum
(Al), 0.1% magnesium (Mg), 0.1% zirconium (Zr), 0.1% titanium (Ti),
0.02% phosphorus (P) and 0.02% sulfur (S) by weight; or 58.07.about.60.17%
iron, 39.about.41.1% nickel, 0.05% chromium, 0.6% manganese, 0.02%
silicon, 0.05% carbon, 0.02% aluminum, 0.05% cobalt (Co), 0.02%
phosphorus and 0.02% sulfur by weight. In another embodiment, the
FeNi-based alloy is a kovar alloy (i.e., iron-nickel-cobalt based
alloy). The kovar alloy can be composed of 52.about.53% iron, 29%
nickel, 17% cobalt, and 1.about.2% residual composition by weight,
the residual composition is selected from the group consisting of
magnesium, manganese, silicon, carbon, aluminum, zirconium, titanium,
phosphorus, sulfur, and an mixture thereof. For example, the kovar
alloy is composed of 52.79% iron, 29% nickel, 17% cobalt, 0.1% magnesium,
0.5% manganese, 0.2% silicon, 0.06% carbon, 0.1% aluminum, 0.1%
zirconium, 0.1% titanium, 0.025% phosphorus, and 0.025% sulfur by
weight.
[0020] The filter 50 usually is an infrared (IR) cut filter which
includes a glass base and an IR cut coating formed on at least one
surface of the glass base member. This IR cut filter can be used
to filter infrared rays.
[0021] Referring to FIG. 2, a digital camera module 200 incorporating
the above-described lens module 100 is shown. The digital camera
module 200 includes the lens module 100 as above described, a holder
60, a base member 70, an image sensor 80 and a cover 90.
[0022] The holder 60 defines an opening 62 therein. An internal
thread 624 is defined on peripheral sidewalls of the opening 62.
The internal thread 624 is engaged together with the external thread
124 of the lens barrel 10 for thereby holding the lens module 100.
[0023] The base member 70 is received in the opening 62 of the
holder 60. The base member 70 usually defines a cavity in a surface
thereof adjacent to the lens module 100 for receiving the image
sensor 80. In the illustrated embodiment, the base member 70 is
made from ceramic.
[0024] The image sensor 80 is fixed in the base member 70 and configured
for detecting optical signals representative of a target image and
converting the optical signals into corresponding electronic signals.
The image sensor 80 usually is a charge coupled device (CCD) or
a complementary metal-oxide semiconductor (CMOS) device.
[0025] The cover 90 is arranged on the base member 70 for covering
the opening of the base member 70. The cover 90 usually is used
to protect the image sensor 80 fixed in the base member 70 from
contaminations, such as dust and/or water vapor. The cover 90 is
usually made of a transparent material, such as transparent glass.
[0026] In summary, the aperture stop and the spacer in the above
described preferred embodiments are made from a material (e.g.,
FeNi-based alloy) having a thermal expansion coefficient matching
with that of glass from which the lens units are made. When such
kinds of aperture stop and/or spacer are employed in optical imaging
apparatuses such as, lens modules and digital camera modules, they
can render the optical imaging apparatuses achieving a better environment-tolerance
and then a high imaging quality.
[0027] 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 present invention. |