U.S. patent application number 13/802247 was filed with the patent office on 2013-10-31 for optical system for camera.
This patent application is currently assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD.. The applicant listed for this patent is SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Kyu Min Chae.
Application Number | 20130286488 13/802247 |
Document ID | / |
Family ID | 49477052 |
Filed Date | 2013-10-31 |
United States Patent
Application |
20130286488 |
Kind Code |
A1 |
Chae; Kyu Min |
October 31, 2013 |
OPTICAL SYSTEM FOR CAMERA
Abstract
Disclosed herein is an optical system for a camera. The optical
system for a camera includes: a first lens having positive
refractive power and a meniscus shape concave toward an image; a
second lens having negative refractive power and a shape concave
toward the image; a third lens having the positive refractive power
and a shape convex toward an object; a fourth lens having the
positive refractive power and a shape convex toward the image; and
a fifth lens having the negative refractive power, a shape convex
toward the object and concave to the image, and one or more
inflection point provided on an image surface.
Inventors: |
Chae; Kyu Min; (Gyeonggi-do,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRO-MECHANICS CO., LTD. |
Gyeonggi-do |
|
KR |
|
|
Assignee: |
SAMSUNG ELECTRO-MECHANICS CO.,
LTD.
Gyeonggi-do
KR
|
Family ID: |
49477052 |
Appl. No.: |
13/802247 |
Filed: |
March 13, 2013 |
Current U.S.
Class: |
359/714 |
Current CPC
Class: |
G02B 13/0045 20130101;
G02B 13/18 20130101; G02B 9/60 20130101 |
Class at
Publication: |
359/714 |
International
Class: |
G02B 13/00 20060101
G02B013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 30, 2012 |
KR |
10-2012-0045609 |
Claims
1. An optical system for a camera comprising: a first lens having
positive refractive power and a meniscus shape concave toward an
image; a second lens having negative refractive power and a shape
concave toward the image; a third lens having the positive
refractive power and a shape convex toward an object; a fourth lens
having the positive refractive power and a shape convex toward the
image; and a fifth lens having the negative refractive power, a
shape convex toward the object and concave to the image, and one or
more inflection point provided on an image surface, wherein the
first and second lenses include an aperture stop disposed
therebetween in order to block unnecessary light in light passing
through the optical system.
2. The optical system for a camera according to claim 1, wherein
the third lens is configured of a lens having a shape in which both
surfaces thereof are convex.
3. The optical system for a camera according to claim 1, wherein
the fourth lens is configured of a lens having a meniscus shape
convex toward the image.
4. The optical system for a camera according to claim 1, wherein
the fifth lens is configured of a lens having a shape concave
toward the image.
5. The optical system for a camera according to claim 1, further
comprising an optical filter provided between the fifth lens and an
image surface, wherein the optical filter is configured of a cover
glass coated with an infrared blocking filter for blocking
excessive infrared rays included in light introduced from the
outside.
6. The optical system for a camera according to claim 1, wherein
the first to fifth lenses are configured of a plastic lens and have
both surfaces configured of an aspherical surface.
7. The optical system for a camera according to claim 1, wherein it
satisfies the following Conditional Equation 1 with respect to
chromatic aberration correction: f3/f<2.0 [Conditional Equation
1] where f3 indicates a focal length of the third lens, and f
indicates a focal length of the entire optical system.
8. The optical system for a camera according to claim 1, wherein it
satisfies the following Conditional Equation 2 with respect to
chromatic aberration correction: R31/f<1.2 [Conditional Equation
2] where R31 indicates a radius of curvature on a surface of the
third lens toward the object, and f indicates a focal length of the
entire optical system.
Description
CROSS REFERENCE(S) TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 U.S.C. Section
119 of Korean Patent Application Serial No. 10-2012-0045609,
entitled "Optical System for Camera" filed on Apr. 30, 2012, which
is hereby incorporated by reference in its entirety into this
application.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates to an optical system for a
camera, and more particularly, to an optical system for a camera
capable of being manufactured in a small size in order to be
mounted in a mobile device and implementing a high resolution.
[0004] 2. Description of the Related Art
[0005] Recently, as the use of a mobile communication unit such as
a mobile communication terminal, a personal digital assistant
(PDA), and a smart phone increases and a service provided through a
communication technology is verified, in addition to a basic
communication function, various types of additional functions have
been mounted. Among them, the mounting of a camera for simple
photographing has been generalized.
[0006] Further, recently, in an optical system of a camera used in
a mobile device such as a cellular phone, the number of pixels has
increased to eight million pixels or more in excess of five million
pixels. In addition, a view angle of 70 degrees or more wider than
a general view angle of about 60 degrees has been demanded.
[0007] However, when a view angle of a lens is increased, an
incident angle of a light ray incident to a lens surface cannot but
be increased, such that performance deterioration may be
intensified even in the same manufacturing tolerance. In addition,
as a pixel size of a sensor is decreased, a required spatial
frequency is increased, such that an optical system having a high
resolution is required.
[0008] When the spatial frequency is increased and the resolution
is increased, sensitivity to the manufacturing tolerance of the
optical system cannot but be increased. Therefore, the development
of the optical system having a high resolution and capable of
decreasing the sensitivity has been required.
[0009] Meanwhile, a high-pixel optical system supporting eight
million pixels, which is an optical system for a camera according
to the related art, is mainly configured of four sheets of lenses
(having a pixel size of 1.4 .mu.m or more), wherein first and
second lens of the four sheets of lenses are in charge of the
entire refractive power of the optical system, and third and fourth
lenses thereof are in charge of image surface field curvature and
distortion to correct aberration that is not corrected by the first
and second lenses.
[0010] In addition, as the first and second lenses, a crown or
flint based glass lens is used. Particularly, the second lens has
negative refractive power and is made of the flint based glass
material to compensate for longitudinal chromatic aberration.
However, it is difficult to satisfy conditions such as
miniaturization and cost reduction with an optical system design
considering a manufacturing cost of an optical system for a mobile
camera.
[0011] Particularly, due to characteristics of the optical system
for a camera applied to the mobile device, a plastic lens is mainly
used in consideration of mass production, size, weight, and cost.
Therefore, it is difficult to satisfy optical performance and
compensate for chromatic aberration with a general optical system
design.
RELATED ART DOCUMENT
Patent Document
[0012] (Patent Document 1) Japanese Patent Laid-Open Publication
No. 1997-211320
SUMMARY OF THE INVENTION
[0013] An object of the present invention is to provide an optical
system for a camera capable of implementing a wide angle and a high
resolution by sequentially disposing five sheets of lenses having
different longitudinal chromatic aberration characteristics and
improving an relative illumination (the ratio of corner
illumination to the center) by disposing an aperture stop between
first and second lenses.
[0014] According to an exemplary embodiment of the present
invention, there is provided an optical system for a camera
including: a first lens having positive refractive power and a
meniscus shape concave toward an image; a second lens having
negative refractive power and a shape concave toward the image; a
third lens having the positive refractive power and a shape convex
toward an object; a fourth lens having the positive refractive
power and a shape convex toward the image; and a fifth lens having
the negative refractive power, a shape convex toward the object and
concave to the image, and one or more inflection point provided on
an image surface, wherein the first and second lenses include an
aperture stop disposed therebetween in order to block unnecessary
light in light passing through the optical system.
[0015] The third lens may be configured of a lens having a shape in
which both surfaces thereof are convex.
[0016] The fourth lens may be configured of a lens having a
meniscus shape convex toward the image.
[0017] The fifth lens may be configured of a lens having a shape
concave toward the object.
[0018] The optical system for a camera may further include an
optical filter provided between the fifth lens and an image
surface, wherein the optical filter is configured of a cover glass
coated with an infrared blocking filter for blocking excessive
infrared rays included in light introduced from the outside.
[0019] The first to fifth lenses may be configured of a plastic
lens and have both surfaces configured of an aspherical
surface.
[0020] The optical system for a camera may satisfy the following
Conditional Equations 1 and 2 with respect to a radius of curvature
of the third lens and a focal length of the entire optical system,
and a focal length of the third lens and a focal length of the
entire optical system
f3/f<2.0 [Conditional Equation 1]
R31/f<1.2 [Conditional Equation 2]
[0021] where f3 indicates a focal length of the third lens, R31
indicates a radius of curvature on a surface of the third lens L3
toward the object, and f indicates a focal length of the entire
optical system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a lens configuration diagram showing a lens
arrangement of an optical system for a camera according to a first
exemplary embodiment of the present invention;
[0023] FIGS. 2A and 2B are, respectively, views showing astigmatism
and distortion of the optical system shown in Table 1 and FIG.
1;
[0024] FIG. 3 is a lens configuration diagram showing a lens
arrangement of an optical system for a camera according to a second
exemplary embodiment of the present invention; and
[0025] FIGS. 4A and 4B are, respectively, views showing astigmatism
and distortion of the optical system shown in Table 3 and FIG.
3.
[0026] FIG. 5 is a lens configuration diagram showing a lens
arrangement of an optical system for a camera according to a third
exemplary embodiment of the present invention;
[0027] FIGS. 6A and 6B are, respectively, views showing astigmatism
and distortion of the optical system shown in Table 5 and FIG.
5.
[0028] FIG. 7 is a lens configuration diagram showing a lens
arrangement of an optical system for a camera according to a fourth
exemplary embodiment of the present invention;
[0029] FIGS. 8A and 8B are, respectively, views showing astigmatism
and distortion of the optical system shown in Table 7 and FIG.
7.
[0030] FIG. 9 is a lens configuration diagram showing a lens
arrangement of an optical system for a camera according to a fifth
exemplary embodiment of the present invention;
[0031] FIGS. 10A and 10B are, respectively, views showing
astigmatism and distortion of the optical system shown in Table 9
and FIG. 9.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] The acting effects and technical configuration with respect
to the objects of an optical system for a camera according to the
present invention will be clearly understood by the following
description in which exemplary embodiments of the present invention
are described with reference to the accompanying drawings.
[0033] However, in the lens configuration diagrams according to the
following exemplary embodiments, a thickness, a size, and a shape
of the lens are slightly exaggerated for a detailed description of
the present invention. Particularly, a shape of a spherical surface
or an aspherical surface suggested in the lens configuration
diagram is only an example. Therefore, the lens is not limited to
the above-mentioned shape.
[0034] FIG. 1 is a lens configuration diagram of an optical system
for a camera according to a first exemplary embodiment of the
present invention. As shown in FIG. 1, the optical system for a
camera according to the first exemplary embodiment of the present
invention may be configured to include a first lens (L1) having a
meniscus shape concave toward an image and positive refractive
power, a second lens L2 having a shape concave toward the image and
negative refractive power, a third lens L3 having a shape convex
toward an object and the positive refractive power, a fourth lens
L4 having a shape convex toward the image and the positive
refractive power, and a fifth lens L5 having a shape convex toward
the object and concave toward the image and the negative refractive
power, wherein the first to fifth lenses L1 to L5 are sequentially
arranged from the object.
[0035] Here, the first and second lenses L1 and L2 may include an
aperture stop (AS) installed therebetween.
[0036] In addition, the optical system for a camera may include an
optical filter (OF) provided between the fifth lens L5 and an image
surface 11, wherein the optical filter (OF) is configured of an
infrared filter for blocking excessive infrared rays in light
passing through the optical system or a cover glass coated with the
infrared filter.
[0037] In the optical system for a camera according to the
exemplary embodiment of the present invention, the aperture stop
(AS) is disposed at the rear of the first lens L1, that is, between
the first and second lenses L1 and L2, thereby making it possible
to decrease sensitivity of the first lens L1 to a tolerance. That
is, in the case in which the aperture stop (AS) is disposed in
front of the first lens L1, an image height is increased due to
light incident to the optical system, such that the first lens L1
may become sensitive to decenter. However, when the aperture stop
(AS) is disposed between the first and second lenses L1 and L2 as
in the exemplary embodiment of the present invention, since an
incident angle of light rays incident to the first lens L1 may be
decreased, the sensitivity of the first lens L1 to the
manufacturing tolerance may be decreased, such that a degree of
freedom in design of the optical system may be increased.
[0038] In addition, when the aperture stop (AS) is disposed between
the first and second lenses L1 and L2, a size of an entrance pupil
imaged by the first lens L1 becomes larger toward an edge of the
image surface, thereby making it possible to improve an ambient
light amount ratio.
[0039] Meanwhile, according to the exemplary embodiment of the
present invention, since the aperture stop (AS) is disposed between
the first and second lenses L1 and L2, an incident angle of the
light ray is increased, such that an incident angle at an image
surface side of the first lens L1 is significantly increased,
thereby making it possible to increase the sensitivity to the
manufacturing tolerance. However, the first lens L1 is designed in
the shape concave toward the image, thereby making it possible to
decrease the incident angle of the light ray to the first lens
L1.
[0040] However, in the case in which a lens concave toward the
image is used as the first lens L1, a chromatic aberration
correction function may be weakened. Since the refractive power at
the image surface of the lens L1 may be changed into the negative
refractive power, the chromatic aberration correction function
capable of being removed using a difference in dispersion property
by the Abbe's number of the first and second lenses L1 and L2 may
be weakened.
[0041] Therefore, according to the exemplary embodiment of the
present invention, the third lens L3 is formed to be convex toward
the object and a relationship between a focal length (f3) of the
third lens L3 and a radius of curvature (R31) on a surface of the
third lens L3 toward the object is used, thereby making it possible
to correct longitudinal chromatic aberration. A more detailed
description thereof will be provided through the following
Conditional Equations.
[0042] Here, the third lens L3 may also be configured of a lens
having a shape in which both surfaces thereof are convex.
[0043] Further, in the optical system according to the exemplary
embodiment of the present invention, the fourth lens L4 may be
configured of a lens having a meniscus shape convex toward the
image.
[0044] In addition, in the optical system according to the
exemplary embodiment of the present invention, the fifth lens L5
may be configured of a lens having a shape concave toward the
object.
[0045] Further, in the optical system according to the exemplary
embodiment of the present invention, all of the first to fifth
lenses L1 to L5 may be configured of a plastic lens, and any one
surface or both surfaces of each of the first and fifth lenses L1
to L5 may be configured of an aspherical surface.
[0046] The reason why one or more surface of the lenses configuring
the optical system according to the exemplary embodiment of the
present invention is configured of the aspherical surface is to
minimize the sheet number of lenses capable of implementing a wide
view angle, thereby configuring the optical system for a camera
that may be compactly manufactured to thereby be used in the mobile
device. In addition, the reason why all of the first to fifth
lenses L1 to L5 are configured of the plastic lens is to configure
the optical system using the plastic lens capable of more easily
manufacturing the aspherical surface lens as compared to the glass
lens, thereby reducing a manufacturing cost and improving a degree
of freedom in design that may alleviate the chromatic aberration
correction and the manufacturing tolerance.
[0047] Meanwhile, as described above, in the optical system
according to the exemplary embodiment of the present invention, the
chromatic aberration is corrected by the following Conditional
Equations 1 and 2, the acting effect of which will be described
below.
f3/f<2.0 [Conditional Equation 1]
[0048] Where f3 indicates a focal length of the third lens, and f
indicates a focal length of the entire optical system.
[0049] Conditional Equation 1 indicates a condition regarding the
chromatic aberration correction of the optical system. In the case
of being out of an upper limit of Conditional Equation 1, focus
adjusting positions for each wavelength in the entire optical
system become different, such that a phenomenon that a color of a
photographed image is blurred may occur.
R31/f<1.2 [Conditional Equation 2]
[0050] Where R31 indicates a radius of curvature on a surface of
the third lens L3 toward the object, and f indicates a focal length
of the entire optical system.
[0051] Conditional Equation 2 also indicates a condition regarding
the chromatic aberration, similar to Conditional Equation 1. When
the surface of the first lens L1 toward the image is formed to be
concave, the radius of curvature of the third lens L3 is increased,
thereby making it possible to correct the chromatic aberration.
Here, in the case of being out of an upper limit of Conditional
Equation 2, since a back focal length (BFL) for each wavelength of
the optical system may be rapidly changed at a portion having a
short wavelength, it is difficult to satisfy optical
characteristics required in the present invention, that is,
correction characteristics of the chromatic aberration.
[0052] Meanwhile, an aspherical surface used in the following
exemplary embodiments is obtained from the known Equation 1, and `E
used in a Conic constant (K) and aspherical surface coefficients
(A, B, C, D, E, and F) and numerals next thereto` indicate the
power of 10. For example, E+02 indicates 10.sup.2, and E-02
indicates 10.sup.-2.
Z = cY 2 1 + 1 - ( 1 + K ) c 2 Y 2 + AY 4 + BY 6 + CY 8 + DY 10 +
EY 12 + FY 14 + [ Equation 1 ] ##EQU00001##
[0053] Where Z indicates a distance from the top of a lens in an
optical axis direction, Y indicates a distance in a direction
vertical to an optical axis, c indicates a reciprocal number of a
radius of curvature (r) at the top of the lens, K indicates a Conic
constant, and A, B, C, D, E, and F indicate aspherical surface
coefficients.
First Exemplary Embodiment
[0054] The following Table 1 shows examples of numerical values
according to a first exemplary embodiment of the present
invention.
[0055] In addition, FIG. 1 is a lens configuration diagram showing
a lens arrangement of an optical system for a camera according to a
first exemplary embodiment of the present invention; and FIGS. 2A
and 2B are, respectively, views showing astigmatism and distortion
of the optical system shown in Table 1 and FIG. 1.
[0056] In the case of the first exemplary embodiment, an effective
focal length (f) of the entire optical system is 4.05 mm. In
addition, all of the first to fifth lenses L1 to L5 are configured
of an aspherical surface plastic lens.
[0057] Further, focal lengths of each lens used in the first
exemplary embodiment are as follows: f1=3.66 mm, f2=-3.80 mm,
f3=5.09 mm, f4=2.27 mm, and f5=-2.10 mm.
TABLE-US-00001 TABLE 1 Radius of Surface Curvature Thickness
Refractive Abbe's No. (R) (mm) Power (n) Number (v) Remarks * 1
1.848 0.62 1.543 56.0 L1 * 2 23.379 0.08 * 3 6.605 0.36 1.635 23.7
L2 * 4 1.729 0.18 * 5 3.287 0.48 1.543 56.0 L3 * 6 -16.575 0.52 * 7
-2.149 0.72 1.543 56.0 L4 * 8 -0.877 0.15 * 9 50.000 0.50 1.543
56.0 L5 * 10 1.114 0.50 11 .infin. 0.30 1.517 64.2 Optical 12
.infin. 0.69 Filter In Table 1, a mark * before the surface number
indicates an aspherical surface. In the case of the first exemplary
embodiment, both surfaces of the first to fifth lenses L1 to L5 are
aspherical surfaces.
[0058] In addition, values of aspherical surface coefficients of
the first exemplary embodiment by Equation 1 are as shown by the
following Table 2.
TABLE-US-00002 TABLE 2 Surface No. K A B C D E 1 0.0000 0.0084
-0.0041 0.0154 -0.0025 -- 2 0.0000 -0.0191 0.0759 -0.0445 -- -- 3
0.0000 -0.1486 0.2118 -0.1457 -- -- 4 0.0000 -0.2033 0.2187 -0.1079
-0.0016 -- 5 0.0000 -0.0914 0.0289 -0.0610 0.1737 -0.0957 6 0.0000
-0.0232 -0.0057 -0.0711 0.1253 -0.0467 7 0.0000 -0.0983 -0.0359
-0.0534 0.1083 -0.0121 8 -1.0000 0.2995 -0.5557 0.7744 -0.7865
0.5168 9 0.0000 -0.0941 -0.0209 0.0523 -0.0267 0.0058 10 -7.4160
-0.0918 0.0364 -0.0124 0.0029 -0.0004
Second Exemplary Embodiment
[0059] The following Table 3 shows examples of numerical values
according to a second exemplary embodiment of the present
invention.
[0060] In addition, FIG. 3 is a lens configuration diagram showing
a lens arrangement of an optical system for a camera according to a
second exemplary embodiment of the present invention; and FIGS. 4A
and 4B are, respectively, views showing astigmatism and distortion
of the optical system shown in Table 3 and FIG. 3.
[0061] In the case of the second exemplary embodiment, an effective
focal length (f) of the entire optical system is 3.94 mm. In
addition, all of the first to fifth lenses L1 to L5 are configured
of an aspherical surface plastic lens.
[0062] Further, focal lengths of each lens used in the second
exemplary embodiment are as follows: f1=3.68 mm, f2=-4.63 mm,
f3=5.55 mm, f4=3.80 mm, and f5=-2.51 mm.
TABLE-US-00003 TABLE 3 Radius of Surface Curvature Thickness
Refractive Abbe's No. (R) (mm) Power (n) Number (v) Remarks * 1
1.858 0.63 1.543 56.0 L1 * 2 22.800 0.08 * 3 4.089 0.32 1.635 23.7
L2 * 4 1.658 0.21 * 5 4.173 0.59 1.543 56.0 13 * 6 -10.312 0.38 * 7
-6.405 0.68 1.543 56.0 L4 * 8 -1.621 0.31 * 9 22.423 0.50 1.543
56.0 L5 * 10 1.275 0.50 11 .infin. 0.30 1.517 64.2 Optical 12
.infin. 0.69 Filter In Table 3, a mark * before the surface number
indicates an aspherical surface. In the case of the second
exemplary embodiment, both surfaces of the first to fifth lenses L1
to L5 are aspherical surfaces.
[0063] In addition, values of aspherical surface coefficients of
the second exemplary embodiment by Equation 1 are as shown by the
following Table 4.
TABLE-US-00004 TABLE 4 Surface No. K A B C D E 1 0.0000 0.0084
-0.0021 0.0109 0.0057 -- 2 0.0000 -0.0456 0.1602 -0.0994 -- -- 3
0.0000 -0.2037 0.3035 -0.2414 -- -- 4 0.0000 -0.2033 0.2528 -0.1822
0.0193 -- 5 0.0000 -0.0538 0.0204 0.0121 0.0318 -0.0224 6 0.0000
-0.0377 -0.1047 0.1179 -0.1157 0.0569 7 0.0000 0.0272 -0.1782
0.2284 -0.2547 0.1598 8 -0.9827 0.0372 -0.0918 0.1788 -0.2169
0.1592 9 0.0000 -0.4123 0.2687 -0.1214 0.0383 -0.0059 10 -7.4160
-0.1583 0.0892 -0.0353 0.0085 -0.0012
Third Exemplary Embodiment
[0064] The following Table 5 shows examples of numerical values
according to a third exemplary embodiment of the present
invention.
[0065] In addition, FIG. 5 is a lens configuration diagram showing
a lens arrangement of an optical system for a camera according to a
third exemplary embodiment of the present invention; and FIGS. 6A
and 6B are, respectively, views showing astigmatism and distortion
of the optical system shown in Table 5 and FIG. 5.
[0066] In the case of the third exemplary embodiment, an effective
focal length (f) of the entire optical system is 4.10 mm. In
addition, all of the first to fifth lenses L1 to L5 are configured
of an aspherical surface plastic lens.
[0067] Further, focal lengths of each lens used in the third
exemplary embodiment are as follows: f1=3.694 mm, f2=-4.620 mm,
f3=6.119 mm, f4=2.402 mm, and f5=-2.093 mm.
TABLE-US-00005 TABLE 5 Radius of Surface Curvature Thickness
Refractive Abbe's No. (R) (mm) Power (n) Number (v) Remarks * 1
1.744 0.60 1.543 56.0 L1 * 2 11.367 0.03 * 3 10.729 0.35 1.635 23.7
L2 * 4 2.292 0.25 * 5 4.92 0.47 1.543 56.0 L3 * 6 -10.035 0.57 * 7
-2.048 0.60 1.543 56.0 L4 * 8 -0.882 0.08 * 9 41.338 0.60 1.543
56.0 L5 * 10 1.106 0.50 11 .infin. 0.30 1.517 64.2 Optical 12
.infin. 0.70 Filter In Table 5, a mark * before the surface number
indicates an aspherical surface. In the case of the third exemplary
embodiment, both surfaces of the first to fifth lenses L1 to L5 are
aspherical surfaces.
[0068] In addition, values of aspherical surface coefficients of
the third exemplary embodiment by Equation 1 are as shown by the
following Table 6.
TABLE-US-00006 TABLE 6 Surface No. K A B C D E 1 0.0000 0.0078
0.0195 -0.0113 -0.0198 -- 2 0.0000 -0.0526 0.1366 -0.0815 -- -- 3
0.0000 -0.1764 0.2553 -0.1908 -- -- 4 0.0000 -0.1762 0.2286 -0.1913
-0.0599 -- 5 0.0000 -0.1167 0.0423 -0.1200 0.1233 -0.0246 6 0.0000
-0.0608 -0.0169 -0.0400 0.0315 0.0061 7 0.0000 -0.0004 -0.0677
0.0671 -0.1283 0.1470 8 -1.0000 0.3049 -0.5433 0.7642 -0.7824
0.5108 9 0.0000 -0.0986 -0.0026 0.0286 -0.0168 0.0041 10 -7.4160
-0.0864 0.0369 -0.0131 0.0029 -0.0004
Fourth Exemplary Embodiment
[0069] The following Table 7 shows examples of numerical values
according to a fourth exemplary embodiment of the present
invention.
[0070] In addition, FIG. 7 is a lens configuration diagram showing
a lens arrangement of an optical system for a camera according to a
fourth exemplary embodiment of the present invention; and FIGS. 8A
and 8B are, respectively, views showing astigmatism and distortion
of the optical system shown in Table 7 and FIG. 7.
[0071] In the case of the fourth exemplary embodiment, an effective
focal length (f) of the entire optical system is 4.10 mm. In
addition, all of the first to fifth lenses L1 to L5 are configured
of an aspherical surface plastic lens.
[0072] Further, focal lengths of each lens used in the fourth
exemplary embodiment are as follows: f1=3.959 mm, f2=-4.925 mm,
f3=5.542 mm, f4=2.763 mm, and f5=-2.302 mm.
TABLE-US-00007 TABLE 7 Radius of Surface Curvature Thickness
Refractive Abbe's No. (R) (mm) Power (n) Number (v) Remarks * 1
1.751 0.59 1.543 56.0 L1 * 2 8.133 0.03 * 3 7.962 0.35 1.635 23.7
L2 * 4 2.222 0.25 * 5 4.185 0.47 1.543 56.0 L3 * 6 -10.466 0.51 * 7
-2.102 0.60 1.543 56.0 L4 * 8 -0.966 0.10 * 9 50.000 0.66 1.543
56.0 L5 * 10 1.219 0.50 11 .infin. 0.30 1.517 64.2 Optical 12
.infin. 0.68 Filter In Table 7, a mark * before the surface number
indicates an aspherical surface. In the case of the fourth
exemplary embodiment, both surfaces of the first to fifth lenses L1
to L5 are aspherical surfaces.
[0073] In addition, values of aspherical surface coefficients of
the fourth exemplary embodiment by Equation 1 are as shown by the
following Table 8.
TABLE-US-00008 TABLE 8 Surface No. K A B C D E 1 0.0000 0.0071
0.0183 -0.0097 -0.0185 -- 2 0.0000 -0.0854 0.1565 -0.0880 -- -- 3
0.0000 -0.2336 0.2973 -0.1993 -- -- 4 0.0000 -0.2176 0.2534 -0.2119
0.0661 -- 5 0.0000 -0.1155 -0.0049 -0.0484 -0.0346 0.0635 6 0.0000
-0.0457 -0.0487 0.0103 -0.0496 0.0423 7 0.0000 -0.0409 -0.1167
0.2662 -0.2476 0.1189 8 -1.0000 0.1786 -0.2042 0.2245 -0.0938
0.0126 9 0.0000 -0.1691 0.1144 -0.0458 0.0083 0.0001 10 -7.4160
-0.0995 0.0546 -0.0231 0.0062 -0.0010
Fifth Exemplary Embodiment
[0074] The following Table 9 shows examples of numerical values
according to a fifth exemplary embodiment of the present
invention.
[0075] In addition, FIG. 9 is a lens configuration diagram showing
a lens arrangement of an optical system for a camera according to a
fifth exemplary embodiment of the present invention; and FIGS. 10A
and 10B are, respectively, views showing astigmatism and distortion
of the optical system shown in Table 9 and FIG. 9.
[0076] In the case of the fifth exemplary embodiment, an effective
focal length (f) of the entire optical system is 4.16 mm. In
addition, all of the first to fifth lenses L1 to L5 are configured
of an aspherical surface plastic lens.
[0077] Further, focal lengths of each lens used in the fifth
exemplary embodiment are as follows: f1=3.749 mm, f2=-4.198 mm,
f3=4.042 mm, f4=4.365 mm, and f5=-2.505 mm.
TABLE-US-00009 TABLE 9 Radius of Surface Curvature Thickness
Refractive Abbe's No. (R) (mm) Power (n) Number (v) Remarks * 1
1.938 0.62 1.543 56.0 L1 * 2 32.755 0.08 * 3 -19.728 0.45 1.635
23.7 L2 * 4 3.145 0.22 * 5 4.193 0.56 1.543 56.0 L3 * 6 -4.434 0.58
* 7 -1.639 0.47 1.543 56.0 L4 * 8 -1.069 0.23 * 9 44.872 0.70 1.543
56.0 L5 * 10 1.319 0.50 11 .infin. 0.30 1.517 64.2 Optical 12
.infin. 0.41 Filter In Table 9, a mark * before the surface number
indicates an aspherical surface. In the case of the fifth exemplary
embodiment, both surfaces of the first to fifth lenses L1 to L5 are
aspherical surfaces.
[0078] In addition, values of aspherical surface coefficients of
the fifth exemplary embodiment by Equation 1 are as shown by the
following Table 10.
TABLE-US-00010 TABLE 10 Surface No. K A B C D E 1 0.0000 0.0067
0.0161 -0.0043 -0.0121 -- 2 0.0000 -0.0246 0.0876 -0.0484 -- -- 3
0.0000 -0.1293 0.1672 -0.1329 -- -- 4 0.0000 -0.1654 0.1759 -0.1349
0.0344 -- 5 0.0000 -0.0963 0.0301 -0.0059 0.0170 -0.0053 6 0.0000
-0.0160 -0.0312 0.0119 0.0135 -0.0028 7 0.0000 0.0869 -0.1379
0.1153 -0.0644 0.0515 8 -1.0000 0.1292 -0.1915 0.2507 -0.2724
0.2071 9 0.0000 -0.1854 0.0877 -0.0323 0.0076 -0.0006 10 -7.4160
-0.0813 0.0343 -0.0112 0.0022 -0.0002
[0079] Meanwhile, values of Conditional Equations 1 and 2 with
respect to the first to fifth exemplary embodiments are as shown in
Table 11.
TABLE-US-00011 TABLE 11 Exemplary Embodiment R31/f f3/f 1 0.811
1.255 2 1.059 1.408 3 1.200 1.492 4 1.020 1.351 5 1.007 0.971
[0080] As shown in the above Table 1, it may be confirmed that the
first to fifth exemplary embodiments of the present invention
satisfy Conditional Equations 1 and 2.
[0081] As set forth above, in the optical system for a camera
according to the exemplary embodiment of the present invention,
five sheets of lenses are configured of the aspherical surface
plastic lens, thereby making it possible to decrease a
manufacturing cost and implement a wide view angle.
[0082] In addition, in the optical system for a camera according to
the exemplary embodiment of the present invention, the third lens
is configured to perform the chromatic aberration correction for
the first lens in a state in which five sheets of lenses are
disposed, such that the first lens having the shape concave toward
the image is used to alleviate the sensitivity to the manufacturing
tolerance, thereby making it possible to improve a degree of
freedom in design.
[0083] Further, in the optical system for a camera according to the
exemplary embodiment of the present invention, the aperture stop is
disposed between the first and second lenses, thereby making it
possible to alleviate the sensitivity to the manufacturing
tolerance of the first lens and improve the ambient light amount
ratio.
[0084] Although the exemplary embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying claims.
Accordingly, such modifications, additions and substitutions should
also be understood to fall within the scope of the present
invention.
* * * * *