U.S. patent application number 13/282481 was filed with the patent office on 2013-04-18 for lens system.
This patent application is currently assigned to HON HAI PRECISION INDUSTRY CO., LTD.. The applicant listed for this patent is HAI-JO HUANG, AN-TZE LEE, XIAO-NA LIU, FANG-YING PENG, SHENG-AN WANG. Invention is credited to HAI-JO HUANG, AN-TZE LEE, XIAO-NA LIU, FANG-YING PENG, SHENG-AN WANG.
Application Number | 20130094100 13/282481 |
Document ID | / |
Family ID | 48061471 |
Filed Date | 2013-04-18 |
United States Patent
Application |
20130094100 |
Kind Code |
A1 |
PENG; FANG-YING ; et
al. |
April 18, 2013 |
LENS SYSTEM
Abstract
A lens system with positive refraction power, in order from the
object-side to the image-side, includes a first lens group with
negative refraction power and a second lens group with positive
refraction power. The first lens group includes a first lens with
negative refraction power, a second lens with positive refraction
power, and a third lens with positive refraction power. The second
lens group includes a fourth lens with negative refraction power, a
fifth lens, and a sixth lens. The lens system satisfies the
following condition: 5<D/F<5.3, wherein: D is a total length
of the lens system; F is a focal length of the lens system.
Inventors: |
PENG; FANG-YING; (Tu-Cheng,
TW) ; HUANG; HAI-JO; (Tu-Cheng, TW) ; WANG;
SHENG-AN; (Tu-Cheng, TW) ; LEE; AN-TZE;
(Tu-Cheng, TW) ; LIU; XIAO-NA; (Shenzhen,
CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PENG; FANG-YING
HUANG; HAI-JO
WANG; SHENG-AN
LEE; AN-TZE
LIU; XIAO-NA |
Tu-Cheng
Tu-Cheng
Tu-Cheng
Tu-Cheng
Shenzhen |
|
TW
TW
TW
TW
CN |
|
|
Assignee: |
HON HAI PRECISION INDUSTRY CO.,
LTD.
Tu-Cheng
TW
HONG FU JIN PRECISION INDUSTRY (ShenZhen) CO., LTD.
Shenzhen City
CN
|
Family ID: |
48061471 |
Appl. No.: |
13/282481 |
Filed: |
October 27, 2011 |
Current U.S.
Class: |
359/723 ;
359/738; 359/793 |
Current CPC
Class: |
G02B 13/04 20130101 |
Class at
Publication: |
359/723 ;
359/793; 359/738 |
International
Class: |
G02B 9/10 20060101
G02B009/10 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 14, 2011 |
CN |
201110311528.7 |
Claims
1. A lens system, in order from the object-side to the image-side
thereof, comprising: a first lens group with negative refraction
power, the first lens group comprising a first lens with negative
refraction power, a second lens with negative refraction power, and
a third lens with positive refraction power; and a second lens
group with positive refraction power, the second lens group
comprising a fourth lens with positive refraction power, a fifth
lens, and a sixth lens; wherein the lens system satisfies the
following condition: 5<D/F<5.3; wherein: D is a total length
of the lens system; F is a focal length of the lens system.
2. The lens system of claim 1, wherein the sixth lens and the fifth
lens are attached together.
3. The lens system of claim 2, wherein the attached fifth and sixth
lenses have a positive refraction power, a focal length of the
attached fifth lens and sixth lens is 11.846 mm.
4. The lens system of claim 1, wherein the lens system further
satisfies the condition: -0.48<F/F1<-0.45; wherein, F is a
focal length of the lens system; F1 is a focal length of the first
lens group.
5. The lens system of claim 1, wherein the lens system further
satisfies the condition: 12.1<|F12/F|<12.6; wherein, F is a
focal length of the lens system; F12 is a focal length of the
second lens.
6. The lens system of claim 1, wherein the first lens, the second
lens, the third lens, the fourth lens, the fifth lens, and the
sixth lens are spherical lenses.
7. The lens system of claim 1, wherein a focal length of the first
lens group is -6.1366 mm; a focal length of the first lens is
-3.685 mm; a focal length of the second lens is -35.695 mm; a focal
length of the third lens 13 is 8.17585 mm.
8. The lens system of claim 1, wherein a focal length of the second
lens group is 3.9915 mm; a focal length of the fourth lens is 5.84
mm.
9. The lens system of claim 1, further comprising an aperture stop,
wherein the aperture stop is installed between the first lens group
and the second lens group.
10. The lens system of claim 9, wherein the aperture stop is
installed between the third lens and the fourth lens, the aperture
stop is configured for adjusting light flux from the firth lens
group to the second lens group.
11. The lens system of claim 1, wherein the lens system is used for
imaging an object to an image plane.
12. The lens system of claim 11, further comprising a color filter,
wherein the color filter is positioned between the second lens
group and the image plane.
13. The lens system of claim 1, wherein a total length of the lens
system is 15 mm, and a focal length of the lens system is 2.9 mm.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The disclosure relates to a lens system.
[0003] 2. Description of Related Art
[0004] Where a short overall length is demanded for use in lens
module for image acquisition. The lens module is mounted in
relatively thin equipment, such as simple digital cameras, webcams
for personal computers, and portable imaging systems in general. In
order to satisfy this demand of compact lens system, conventional
lens systems reduce the number of lenses to shorten the overall
length, but this will decrease the resolution. Increasing the
number of lenses can increase resolution, but will also increase
the overall length of the lens systems.
[0005] What is needed, therefore, is a lens system to overcome the
above-described problem.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Many aspects of the present disclosure 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 present disclosure.
[0007] FIG. 1 is a schematic view of a lens system of the present
disclosure.
[0008] FIGS. 2.about.4 are graphs respectively showing spherical
aberration, field curvature, distortion and lateral chromatic
aberration occurring in the lens system of FIG. 1.
DETAILED DESCRIPTION
[0009] Embodiments of the disclosure will now be described in
detail below, with reference to the accompanying drawings.
[0010] Referring to FIG. 1, a lens system 100 of the present
disclosure is used for imaging an object to an image plane 40. The
lens system 100 includes, in this order from the object-side to the
image-side, a first lens group 10 with negative refraction power, a
second lens group 20 with positive refraction power, and a color
filter 30. In the embodiment, the lens system 100 has positive
refraction power and a total length of the lens system 100 is 15
mm, and a focal length of the lens system 100 is 2.9 mm.
[0011] In the embodiment, the first lens group 10 includes, in
order from the object-side to the image-side of the lens system
100, a first lens 11 having negative refraction power, a second
lens 12 having negative refraction power, and a third lens 13 with
positive refraction power. In the embodiment, a focal length F1 of
the first lens group 10 is -6.1366 mm; a focal length F11 of the
first lens 11 is -3.685 mm; a focal length F12 of the second lens
12 is -35.695 mm; a focal length F13 of the third lens 13 is
8.17585 mm. The first lens 11 includes, in order from the
object-side to the image-side of the lens system 100, a first
surface S1 and a second surface S2. The second lens 12 includes, in
this order from the object-side to the image-side of the lens
system 100, a third surface S3, and a fourth surface S4. The third
lens 13 includes, in this order from the object-side to the
image-side of the lens system 100, a fifth surface S5 and a sixth
surface S6. The first lens 11 and the second lens 12 are spaced
from each other, therefore, an opaque plate (not shown) can be
sandwiched between the first lens 11 and the second lens 12 for
blocking off-axis light rays entering the lens system 100.
[0012] The second lens group 20 has a positive refractive power and
includes, in the order from the object-side to the image-side of
the lens system 100, a fourth lens 21 having positive refraction
power, a fifth lens 22, and a sixth lens 23. In the embodiment, the
fifth lens 22 and the sixth lens 23 are attached together to form a
single unit. The attached fifth lens 22 and the sixth lens 23 have
a positive refraction power. In the embodiment, a focal length F2
of the second lens group 20 is 3.9915 mm; a focal length F21 of the
fourth lens 21 is 5.84 mm; a focal length F22 of the adhered fifth
lens 22 and sixth lens 23 is 11.846 mm. The fourth lens 21
includes, in this order from the object-side to the image-side of
the lens system 100, a seventh surface S7, and an eighth surface
S8. The fifth lens 22 includes, in this order from the object-side
to the image-side of the lens system 100, a ninth surface S9, and a
tenth surface S10. The sixth lens 23 includes, in this order from
the object-side to the image-side of the lens system 100, the tenth
surface S10 and an eleventh surface S11.
[0013] The lens system 100 further includes an aperture stop 25
installed between the first lens group 10 and the second lens group
20. In particular, the aperture stop 25 is installed between the
third lens 13 and the fourth lens 21. The aperture stop 25 adjusts
light flux from the first lens group 10 to the second lens group
20. In addition, the aperture stop 25 facilitates uniform light
transmission when light passes through the second lens group 20 to
correct coma aberrations of the lens system 100. To minimize the
manufacture cost and the total length of the lens system 100, the
aperture stop 25 can be a black adhesive positioned on a periphery
of the seventh surface S7 of the fourth lens 21.
[0014] The color filter 30 includes, in the order from the
object-side to the image-side of the lens system 100, a twelfth
surface S12 and a thirteenth surface S13. The color filter 30 is
installed between the sixth lens 23 and the image plane 40.
[0015] In order to obtain low distortion, good imaging quality and
a compact configuration, the lens system 100 satisfies the
following conditions:
5<D/F<5.3; (1)
[0016] wherein, D is a total length of the lens system 100; F is a
focal length of the lens system 100. The conditions (1) can
favorably limit the relation between the focal length of every lens
group and the focal length of the lens system 100 to obtain a high
resolution. If the ratio D/F of condition (1) is smaller than 5,
the first lens 10 and the second lens 20 are too close to each
other. On the other hand, if the ratio D/F of condition (1) is
larger than 5.3, the total length D of the lens system 100 tends to
be too long. This in turn tends to make the distance from the first
surface 11 of the first lens 10 to the image plane too long, which
also tends to increase the overall length of the lens system
100.
[0017] In one embodiment, the lens system 100 further satisfies the
following condition:
-0.48<F/F1<-0.45; (2)
[0018] wherein, F is a focal length of the lens system 100; F1 is a
focal length of the first lens group 10. The conditions (2) can
favorably limit the focal length of the first lens group 10.
[0019] In one embodiment, the lens system 100 further satisfies the
following condition:
12.1<|F12/F|<12.6 (3)
[0020] wherein, F is a focal length of the lens system 100; F12 is
a focal length of the second lens 12. The conditions (3) can reduce
the aberration of the field curvature and spherical aberration in
the lens system 100.
[0021] The first lens 11, the second lens 12, the third lens 13,
the fourth lens 21, the fifth lens 22, and the sixth lens 23 are
spherical lenses.
[0022] Example diagrams of the lens system 100 will be described
below with reference to FIGS. 2-4. The disclosure is not limited to
these examples. The following are symbols used in each exemplary
embodiment.
[0023] F.sub.No: F number;
[0024] 2.omega.: field angle;
[0025] ri: radius of curvature of the surface Si;
[0026] Di: distance between surfaces on the optical axis of the
surface Si and the surface Si+1;
[0027] Ni: refractive index of the surface Si;
[0028] Vi: Abbe constant of the surface Si; and
[0029] F: the focal length of the lens system 100.
[0030] Tables 1-2 show the specifications of an embodiment of the
lens system 100.
TABLE-US-00001 TABLE 1 Surface ri(mm) Di(mm) ni vi S1 32.751 0.8
1.6667 48.43 S2 2.27 1.03 -- -- S3 3.045 1.066 1.583 59.45 S4 2.31
0.384 -- -- S5 17.96 1.03 1.805 25.45 S6 -10.27 1.354 -- -- S7
-11.810 1.654 1.755 52.32 S8 -3.42 0.0446 -- -- S9 11.976 2.159
1.713 53.93 S10 -3.592 0.4 2 19.317 S11 -9.277 3.126 -- -- S12
infinite 1 1.5168 64.167 S13 infinite 0.946 -- -- Image plane
infinite -- -- 40
TABLE-US-00002 TABLE 2 F(mm) 2.9 FOV(2w) 156.2 F number 2.5
[0031] FIGS. 2-4, are graphs of aberrations (spherical aberration,
field curvature, distortion, and lateral chromatic aberration) of
the lens system 100. In FIG. 2, curves are spherical aberration
characteristic curves of a1 light (wavelength: 436 nm), a2 light
(wavelength: 486 nm), a3 light (wavelength: 546 nm), a4 light
(wavelength: 588 nm), and a5 light (wavelength: 588 nm) of the lens
system 100. The spherical aberration of the lens system 100 of the
first exemplary embodiment is from -0.1 mm to 0.1 mm. As
illustrated in FIG. 3, the curves t1.about.t5 and s1.about.s5 are
respectively the tangential field curvature curve and the sagittal
field curvature curve. The field curvature of the lens system 100
is from -0.5 mm to 0.5 mm. In FIG. 4, the distortion of the lens
system 100 is from -50% to 0%.
[0032] In the exemplary embodiment, though the overall length of
the lens system 100 is reduced, aberrations of the lens system 100
are maintained within an acceptable range. That is, the lens system
100 keeps chromatic aberrations at a minimum while reducing the
total length of the lens system 100.
[0033] Aberrations occurring in the lens system 100 are
controlled/corrected to an acceptable level, and changes in
aberrations are reduced to acceptable levels as well, accordingly,
a high resolution of the lens system 100 is obtained, and
maintained over the entire zooming range of the lens system
100.
[0034] While certain embodiments have been described and
exemplified above, various other embodiments will be apparent to
those skilled in the art from the foregoing disclosure. The
disclosure is not limited to the particular embodiments described
and exemplified, and the embodiments are capable of considerable
variation and modification without departure from the scope of the
appended claims.
* * * * *