U.S. patent application number 15/585165 was filed with the patent office on 2018-09-27 for optical imaging system.
This patent application is currently assigned to Genius Electronic Optical Co., Ltd.. The applicant listed for this patent is Genius Electronic Optical Co., Ltd.. Invention is credited to Jia-Sin Jhang, Maozong Lin, Yanxuan Yin.
Application Number | 20180275371 15/585165 |
Document ID | / |
Family ID | 59871398 |
Filed Date | 2018-09-27 |
United States Patent
Application |
20180275371 |
Kind Code |
A1 |
Jhang; Jia-Sin ; et
al. |
September 27, 2018 |
OPTICAL IMAGING SYSTEM
Abstract
An optical imaging system includes a reflector, a first lens
element, a second lens element, a third lens element, a fourth lens
element, and a fifth lens element from an object side to an image
side in order along an optical axis. The first lens element to the
fifth lens element each include an object-side surface and an
image-side surface. The object-side surface of the first lens
element has a convex portion in a vicinity of the optical axis. The
material of the second lens element is plastic material. The
image-side surface of the third lens element has a convex portion
or a concave portion in the vicinity of the optical axis. At least
one of the object-side surface and the image-side surface of the
fourth lens element is an aspheric surface. The object-side surface
and the image-side surface of the fifth lens element are aspheric
surfaces.
Inventors: |
Jhang; Jia-Sin; (Taichung
City, TW) ; Yin; Yanxuan; (Xiamen, CN) ; Lin;
Maozong; (Xiamen, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Genius Electronic Optical Co., Ltd. |
Taichung City |
|
TW |
|
|
Assignee: |
Genius Electronic Optical Co.,
Ltd.
Taichung City
TW
|
Family ID: |
59871398 |
Appl. No.: |
15/585165 |
Filed: |
May 3, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 9/60 20130101; G02B
13/0045 20130101 |
International
Class: |
G02B 13/00 20060101
G02B013/00; G02B 9/60 20060101 G02B009/60 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 24, 2017 |
CN |
201710182902.5 |
Claims
1. An optical imaging system, comprising a reflector, a first lens
element, a second lens element, a third lens element, a fourth lens
element and a fifth lens element in order along an optical axis
from an object side to an image side, wherein the optical axis
comprises a first optical axis and a second optical axis not
coinciding with the first optical axis, the first optical axis and
the second optical axis intersect at an intersection point on a
reflective surface of the reflector, and lens elements of the
optical imaging system which have refractive powers are only
disposed along the second optical axis, wherein the first lens
element to the fifth lens element each comprises an object-side
surface facing towards the object side and allowing imaging rays to
pass through and an image-side surface facing towards the image
side and allowing the imaging rays to pass through, and wherein the
first lens element is arranged to be a lens element having
refracting power in a first order from the reflector to the image
side, the second lens element is arranged to be a lens element
having refracting power in a second order from the reflector to the
image side, the third lens element is arranged to be a lens element
having refracting power in a third order from the reflector to the
image side, the fourth lens element is arranged to be a lens
element having refracting power in a fourth order from the
reflector to the image side, and the fifth lens element is arranged
to be a lens element having refracting power in a fifth order from
the reflector to the image side; the object-side surface of the
first lens element having a convex portion in a vicinity of the
optical axis; a material of the second lens element being a plastic
material, the object-side surface of the second lens element having
a convex portion in a vicinity of the optical axis; the image-side
surface of the third lens element having a convex portion in a
vicinity of the optical axis or a concave portion in the vicinity
of the optical axis; at least one of the object-side surface and
the image-side surface of the fourth lens element being an aspheric
surface; the object-side surface and the image-side surface of the
fifth lens element being aspheric surfaces, the image-side surface
of the fifth lens element having a convex portion in a vicinity of
a periphery of the fifth lens element; and the optical imaging
system further comprising an aperture stop disposed between the
reflector and the third lens element; wherein the optical imaging
system satisfies: (G23+T3+G34)/(T1+G12+T2).ltoreq.1.8, wherein G23
represents an air gap from the second lens element to the third
lens element along the second optical axis, T3 represents a
thickness of the third lens element along the second optical axis,
G34 represents an air gap from the third lens element to the fourth
lens element along the second optical axis, T1 represents a
thickness of the first lens element along the second optical axis,
G12 represents an air gap from the first lens element to the second
lens element along the second optical axis, and T2 represents a
thickness of the second lens element along the second optical
axis.
2. The optical imaging system according to claim 1, wherein the
optical imaging system satisfies: 0.6.ltoreq.OP2/EFL.ltoreq.2.7,
wherein OP2 represents a distance from the intersection point to an
image plane of the optical imaging system along the second optical
axis, and EFL represents an effective focal length of the optical
imaging system.
3. The optical imaging system according to claim 1, wherein the
optical imaging system is configured to enable the imaging rays to
enter from light inlet and arrive at an image plane of the optical
imaging system through the optical imaging system for imaging, and
the optical imaging system satisfies:
2.2.ltoreq.OP2/OP1.ltoreq.8.8, wherein OP2 represents a distance
from the intersection point to the image plane of the optical
imaging system along the second optical axis, and OP1 represents a
distance from the light inlet to the intersection point along the
first optical axis.
4. The optical imaging system according to claim 1, wherein the
optical imaging system satisfies: |.nu.5-.nu.2|.ltoreq.30.0,
wherein .nu.5 represents an Abbe number of the fifth lens element,
and .nu.2 represents an Abbe number of the second lens element.
5. The optical imaging system according to claim 1, wherein the
optical imaging system satisfies: TL/BFL.ltoreq.3.5, wherein TL
represents a distance from the object-side surface of the first
lens element to the image-side surface of the fifth lens element
along the second optical axis, and BFL represents a distance from
the image-side surface of the fifth lens element to an image plane
of the optical imaging system along the second optical axis.
6. The optical imaging system according to claim 1, wherein the
optical imaging system satisfies: ALT/(T4+T5).ltoreq.3.5, wherein
ALT represents a sum of thicknesses of the first lens element, the
second lens element, the third lens element, the fourth lens
element and the fifth lens element along the second optical axis,
T4 represents a thickness of the fourth lens element along the
second optical axis, and T5 represents a thickness of the fifth
lens element along the second optical axis.
7. (canceled)
8. The optical imaging system according to claim 1, wherein the
optical imaging system satisfies: TTL/(T1+T2+T3).ltoreq.6.0,
wherein TTL represents a distance from the object-side surface of
the first lens element to an image plane of the optical imaging
system along the second optical axis.
9. The optical imaging system according to claim 1, wherein the
optical imaging system satisfies: AAG/(G12+G45).ltoreq.5.6, wherein
AAG represents a sum of four air gaps from the first lens element
to the fifth lens element along the second optical axis, and G45
represents an air gap from the fourth lens element to the fifth
lens element along the second optical axis.
10. The optical imaging system according to claim 1, wherein four
air gaps from the first lens element to the fifth lens element
along the second optical axis are fixed gaps.
11. An optical imaging system, configured to enable imaging rays to
enter from a light inlet and arrive at an image plane of the
optical imaging system through the optical imaging system for
imaging, wherein the optical imaging system comprises a reflector,
a first lens element, a second lens element, a third lens element,
a fourth lens element and a fifth lens element in order along an
optical axis from an object side to an image side, the optical axis
comprises a first optical axis and a second optical axis not
coinciding with the first optical axis, the first optical axis and
the second optical axis intersect at an intersection point on a
reflective surface of the reflector, and the first lens element,
the second lens element, the third lens element, the fourth lens
element and the fifth lens element are arranged in order along the
second optical axis, wherein the first lens element to the fifth
lens element each comprises an object-side surface facing towards
the object side and allowing imaging rays to pass through and an
image-side surface facing towards the image side and allowing the
imaging rays to pass through, and wherein the first lens element is
arranged to be a lens element having refracting power in a first
order from the reflector to the image side, the second lens element
is arranged to be a lens element having refracting power in a
second order from the reflector to the image side, the third lens
element is arranged to be a lens element having refracting power in
a third order from the reflector to the image side, the fourth lens
element is arranged to be a lens element having refracting power in
a fourth order from the reflector to the image side, and the fifth
lens element is arranged to be a lens element having refracting
power in a fifth order from the reflector to the image side; the
object-side surface of the first lens element having a convex
portion in a vicinity of the optical axis; a material of the second
lens element being a plastic material, the object-side surface of
the second lens element having a convex portion in a vicinity of
the optical axis; the image-side surface of the third lens element
having a convex portion in a vicinity of the optical axis or a
concave portion in the vicinity of the optical axis; at least one
of the object-side surface and the image-side surface of the fourth
lens element being an aspheric surface; the object-side surface and
the image-side surface of the fifth lens element being aspheric
surfaces, the image-side surface of the fifth lens element having a
convex portion in a vicinity of a periphery of the fifth lens
element; the optical imaging system further comprising an aperture
stop disposed between the reflector and the third lens element; and
the optical imaging system satisfying:
(OP1/ImgH).times.Fno.ltoreq.3.1, wherein OP1 represents a distance
from the light inlet to the intersection point along the first
optical axis, ImgH represents an image height of the optical
imaging system, and Fno represents an f-number of the optical
imaging system.
12. The optical imaging system according to claim 11, wherein the
optical imaging system further satisfies:
1.2.ltoreq.OP2/ALT.ltoreq.4.9, wherein OP2 represents a distance
from the intersection point to the image plane of the optical
imaging system along the second optical axis, and ALT represents a
sum of thicknesses of the first lens element, the second lens
element, the third lens element, the fourth lens element and the
fifth lens element along the second optical axis.
13. The optical imaging system according to claim 11, wherein the
optical imaging system further satisfies:
1.6.ltoreq.TTL/OP1.ltoreq.6.5, wherein TTL represents a distance
from the object-side surface of the first lens element to the image
plane of the optical imaging system along the second optical
axis.
14. The optical imaging system according to claim 11, wherein the
optical imaging system further satisfies:
|.nu.4-.nu.3|.ltoreq.30.0, wherein .nu.4 represents an Abbe number
of the fourth lens element, and .nu.3 represents an Abbe number of
the third lens element.
15. The optical imaging system according to claim 11, wherein the
optical imaging system further satisfies: ALT/BFL.ltoreq.2.5,
wherein ALT represents a sum of thicknesses of the first lens
element, the second lens element, the third lens element, the
fourth lens element and the fifth lens element along the second
optical axis, and BFL represents a distance from the image-side
surface of the fifth lens element to the image plane of the optical
imaging system along the second optical axis.
16. The optical imaging system according to claim 11, wherein the
optical imaging system further satisfies: TL/(T4+T5).ltoreq.4.5,
wherein TL represents a distance from the object-side surface of
the first lens element to the image-side surface of the fifth lens
element along the second optical axis, T4 represents a thickness of
the fourth lens element along the second optical axis, and T5
represents a thickness of the fifth lens element along the second
optical axis.
17. The optical imaging system according to claim 11, wherein the
optical imaging system further satisfies:
(G23+T3+G34)/(T4+G45+T5).ltoreq.1.7, wherein G23 represents an air
gap from the second lens element to the third lens element along
the second optical axis, T3 represents a thickness of the third
lens element along the second optical axis, G34 represents an air
gap from the third lens element to the fourth lens element along
the second optical axis, T4 represents a thickness of the fourth
lens element along the second optical axis, G45 represents an air
gap from the fourth lens element to the fifth lens element along
the second optical axis, and T5 represents a thickness of the fifth
lens element along the second optical axis.
18. The optical imaging system according to claim 11, wherein the
optical imaging system further satisfies: TTL/EFL.ltoreq.1.2,
wherein TTL represents a distance from the object-side surface of
the first lens element to the image plane of the optical imaging
system along the second optical axis, and EFL represents an
effective focal length of the optical imaging system.
19. The optical imaging system according to claim 11, wherein the
optical imaging system further satisfies:
TL/(T1+G12+T2).ltoreq.4.2, wherein TL represents a distance from
the object-side surface of the first lens element to the image-side
surface of the fifth lens element along the second optical axis, T1
represents a thickness of the first lens element along the second
optical axis, G12 represents an air gap from the first lens element
to the second lens element along the second optical axis, and T2
represents a thickness of the second lens element along the second
optical axis.
20. An optical imaging system, comprising a reflector, a first lens
element, a second lens element, a third lens element, a fourth lens
element and a fifth lens element in order along an optical axis
from an object side to an image side, wherein the optical axis
comprises a first optical axis and a second optical axis not
coinciding with the first optical axis, the first optical axis and
the second optical axis intersect at an intersection point on a
reflective surface of the reflector, and the first lens element,
the second lens element, the third lens element, the fourth lens
element and the fifth lens element are arranged in order along the
second optical axis and each has a radius of the clear aperture
less than or equal to 2.5 mm, wherein the first lens element to the
fifth lens element each comprises an object-side surface facing
towards the object side and allowing imaging rays to pass through
and an image-side surface facing towards the image side and
allowing the imaging rays to pass through, and wherein the first
lens element is arranged to be a lens element having refracting
power in a first order from the reflector to the image side, the
second lens element is arranged to be a lens element having
refracting power in a second order from the reflector to the image
side, the third lens element is arranged to be a lens element
having refracting power in a third order from the reflector to the
image side, the fourth lens element is arranged to be a lens
element having refracting power in a fourth order from the
reflector to the image side, and the fifth lens element is arranged
to be a lens element having refracting power in a fifth order from
the reflector to the image side; the object-side surface of the
first lens element having a convex portion in a vicinity of the
optical axis; a material of the second lens element being a plastic
material, the object-side surface of the second lens element having
a convex portion in a vicinity of the optical axis; the image-side
surface of the third lens element having a convex portion in a
vicinity of the optical axis or a concave portion in the vicinity
of the optical axis; at least one of the object-side surface and
the image-side surface of the fourth lens element being an aspheric
surface; the object-side surface and the image-side surface of the
fifth lens element being aspheric surfaces, the image-side surface
of the fifth lens element having a convex portion in a vicinity of
a periphery of the fifth lens element; the optical imaging system
further comprising an aperture stop disposed between the first lens
element and the third lens element; and the optical imaging system
satisfying: 7.5 mm.ltoreq.EFL.ltoreq.13.5 mm, wherein EFL
represents an effective focal length of the optical imaging system.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Chinese
application serial no. 201710182902.5, filed on Mar. 24, 2017. The
entirety of the above-mentioned patent application is hereby
incorporated by reference herein and made a part of this
specification.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The invention relates to an optical imaging system.
2. Description of Related Art
[0003] In recent years, the popularity of portable electronic
products such as cell phones and digital cameras enhances flourish
development of techniques related to image modules. The image
modules mainly include elements such as an optical imaging lens, a
module holder unit and a sensor, and the demand for minimizing the
image module also increases due to the trend of the compact and
slim design of mobile phones and digital cameras. Along with the
progress in the technologies related to charge coupled devices
(CCD) and complementary metal oxide semiconductors (CMOS) and
reduction in the dimensions of the CCD and CMOS, the length of the
optical imaging lens installed in the image module also has to be
correspondingly reduced. However, in order to avoid reduction in
photography effect and quality, preferable optical properties
should also be achieved while the length of the optical imaging
lens is minified. The imaging quality and volume are two of the
most important characteristics for an optical imaging lens.
[0004] As the specifications of portable electronic products (such
as cell phones, cameras, tablet PCs, personal digital assistants,
photographic devices used in cars, virtual reality trackers, etc.)
are ever-changing, key elements, i.e. optical imaging lenses, are
also developed diversely, which can be applied to not only
image-taking and recording, but also environmental monitoring,
driving recording and so on. Moreover, along with the advance of
image sensing technology, consumers' demands for imaging quality
also increases.
[0005] However, the optical imaging lens design cannot achieve the
production of an optical imaging lens having both imaging quality
and small size simply by reducing the size and maintaining the
original ratio of a lens having good imaging quality, the design
process involves material properties, and actual issues on the
production line such as assembly yield also needs to be
considered.
[0006] The technical difficulty of manufacturing a miniaturized
lens is significantly greater than that of a traditional lens, and
therefore how to manufacture an optical imaging lens satisfying
consumer electronic product requirements and continuing to increase
the imaging quality thereof have always been highly desired goals
of production, government, and academia in the field.
[0007] In addition, with the increase in photographing demands plus
the recent demands for telephotography, an optical zoom-like effect
can be achieved better by a telephoto lens with a wide angle lens.
The larger the focal length of the optical imaging lens is, the
larger the telephoto magnification of the optical imaging lens is,
and therefore, it is not easy to shorten the length of the
telephoto lens. Moreover, the lens structure design where the lens
elements are arranged on a straight line from an object to an image
plane cannot satisfy the demands for current portable electronic
products used with the telephoto lens. This is because current
portable electronic products are most developed toward a goal of
miniaturization, but the lens with the lens elements arranged on a
straight line and having an overly large length cannot be placed in
the thinned portable electronic products. The dilemma of reducing
the lens length or increasing the magnification and the maintenance
of imaging quality result in difficulty in the design of the
optical imaging lens.
SUMMARY OF THE INVENTION
[0008] The invention provides an optical imaging system capable of
maintaining preferable optical properties in a condition that a
lens depth is reduced.
[0009] An embodiment of the invention provides an optical imaging
system, including a reflector, a first lens element, a second lens
element, a third lens element, a fourth lens element and a fifth
lens element in order along an optical axis from an object side to
an image side. The optical axis includes a first optical axis and a
second optical axis not coinciding with the first optical axis. The
first optical axis and the second optical axis intersect at an
intersection point on a reflective surface of the reflector, and
the lens elements of the optical imaging system which have
refractive powers are only disposed along the second optical axis.
The first lens element to the fifth lens element each includes an
object-side surface facing towards the object side and allowing
imaging rays to pass through and an image-side surface facing
towards the image side and allowing the imaging rays to pass
through. The object-side surface of the first lens element has a
convex portion in a vicinity of the optical axis, and a material of
the second lens element is a plastic material. The image-side
surface of the third lens element has a convex portion in the
vicinity of the optical axis or a concave portion in the vicinity
of the optical axis. At least one of the object-side surface and
the image-side surface of the fourth lens element is an aspheric
surface, and the object-side surface and the image-side surface of
the fifth lens element are aspheric surfaces. The optical imaging
system further includes an aperture stop disposed between the
reflector and the third lens element.
[0010] An embodiment of the invention provides an optical imaging
system, configured to enable imaging rays to enter from a light
inlet and arrive at an image plane of the optical imaging system
through the optical imaging system for imaging. The optical imaging
system includes a reflector, a first lens element, a second lens
element, a third lens element, a fourth lens element and a fifth
lens element in order along an optical axis from an object side to
an image side. The optical axis includes a first optical axis and a
second optical axis not coinciding with the first optical axis, the
first optical axis and the second optical axis intersect at an
intersection point on a reflective surface of the reflector, and
the first lens element, the second lens element, the third lens
element, the fourth lens element and the fifth lens element are
arranged in order along the second optical axis. The first lens
element to the fifth lens element each comprises an object-side
surface facing towards the object side and allowing imaging rays to
pass through and an image-side surface facing towards the image
side and allowing the imaging rays to pass through. The object-side
surface of the first lens element has a convex portion in a
vicinity of the optical axis, and a material of the second lens
element is a plastic material. The image-side surface of the third
lens element has a convex portion in the vicinity of the optical
axis or a concave portion in the vicinity of the optical axis. At
least one of the object-side surface and the image-side surface of
the fourth lens element is an aspheric surface, and the object-side
surface and the image-side surface of the fifth lens element are
aspheric surfaces. The optical imaging system further includes an
aperture stop disposed between the reflector and the third lens
element. The optical imaging system satisfies:
(OP1/ImgH).times.Fno.ltoreq.3.1, wherein OP1 represents a distance
from the light inlet to the intersection point along the first
optical axis, ImgH represents an image height of the optical
imaging system, and Fno represents an f-number of the optical
imaging system.
[0011] An embodiment of the invention provides an optical imaging
system, including a reflector, a first lens element, a second lens
element, a third lens element, a fourth lens element and a fifth
lens element in order along an optical axis from an object side to
an image side. The optical axis includes a first optical axis and a
second optical axis not coinciding with the first optical axis, and
the first optical axis and the second optical axis intersect at an
intersection point on a reflective surface of the reflector. the
first lens element, the second lens element, the third lens
element, the fourth lens element and the fifth lens element are
arranged in order along the second optical axis and each has a
radius of the clear aperture less than or equal to 2.5 millimeter
(mm). The first lens element to the fifth lens element each
includes a an object-side surface facing towards the object side
and allowing imaging rays to pass through and an image-side surface
facing towards the image side and allowing the imaging rays to pass
through. The object-side surface of the first lens element has a
convex portion in a vicinity of the optical axis, and a material of
the second lens element is a plastic material. The image-side
surface of the third lens element has a convex portion in the
vicinity of the optical axis or a concave portion in the vicinity
of the optical axis. At least one of the object-side surface and
the image-side surface of the fourth lens element is an aspheric
surface, and the object-side surface and the image-side surface of
the fifth lens element are aspheric surfaces. The optical imaging
system further includes an aperture stop disposed between the first
lens element and the third lens element. The optical imaging system
satisfies: 7.5 mm.ltoreq.EFL.ltoreq.13.5 mm, wherein EFL represents
an effective focal length of the optical imaging system.
[0012] Based on the above, the optical imaging system of the
embodiments of the invention can bring the following advantageous
effects: the optical imaging system still can achieve the optical
performance of effectively overcoming aberrations and provide
preferable imaging quality by the arrangement of the reflector and
the object-side surfaces or the image-side surfaces of the lens
elements or according to designs of the conditional formulas in the
condition that the system length or the lens depth of the optical
imaging system is reduced.
[0013] To make the above features and advantages of the invention
more comprehensible, embodiments accompanied with drawings are
described in detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
[0015] FIG. 1 is a schematic view illustrating a surface structure
of a lens element.
[0016] FIG. 2 is a schematic view illustrating a concave and convex
surface structure of a lens element and a ray focal point.
[0017] FIG. 3 is a schematic view illustrating a surface structure
of a lens element according to a first example.
[0018] FIG. 4 is a schematic view illustrating a surface structure
of a lens element according to a second example
[0019] FIG. 5 is a schematic view illustrating a surface structure
of a lens element according to a third example.
[0020] FIG. 6 is a schematic view illustrating an optical imaging
system according to a first embodiment of the invention.
[0021] FIG. 7A to FIG. 7D illustrate a longitudinal spherical
aberration and other aberrations of the optical imaging system
according to the first embodiment of the invention.
[0022] FIG. 8 shows detailed optical data pertaining to the optical
imaging system according to the first embodiment of the
invention.
[0023] FIG. 9 shows aspheric parameters pertaining to the optical
imaging system according to the first embodiment of the
invention.
[0024] FIG. 10 is a schematic view illustrating an optical imaging
system according to a second embodiment of the invention.
[0025] FIG. 11A to FIG. 11D illustrate a longitudinal spherical
aberration and other aberrations of the optical imaging system
according to the second embodiment of the invention.
[0026] FIG. 12 shows detailed optical data pertaining to the
optical imaging system according to the second embodiment of the
invention.
[0027] FIG. 13 shows aspheric parameters pertaining to the optical
imaging system according to the second embodiment of the
invention.
[0028] FIG. 14 is a schematic view illustrating an optical imaging
system according to a third embodiment of the invention.
[0029] FIG. 15A to FIG. 15D illustrate a longitudinal spherical
aberration and other aberrations of the optical imaging system
according to the third embodiment of the invention.
[0030] FIG. 16 shows detailed optical data pertaining to the
optical imaging system according to the third embodiment of the
invention.
[0031] FIG. 17 shows aspheric parameters pertaining to the optical
imaging system according to the third embodiment of the
invention.
[0032] FIG. 18 is a schematic view illustrating an optical imaging
system according to a fourth embodiment of the invention.
[0033] FIG. 19A to FIG. 19D illustrate a longitudinal spherical
aberration and other aberrations of the optical imaging system
according to the fourth embodiment of the invention.
[0034] FIG. 20 shows detailed optical data pertaining to the
optical imaging system according to the fourth embodiment of the
invention.
[0035] FIG. 21 shows aspheric parameters pertaining to the optical
imaging system according to the fourth embodiment of the
invention.
[0036] FIG. 22 is a schematic view illustrating an optical imaging
system according to a fifth embodiment of the invention.
[0037] FIG. 23A to FIG. 23D illustrate a longitudinal spherical
aberration and other aberrations of the optical imaging system
according to the fifth embodiment of the invention.
[0038] FIG. 24 shows detailed optical data pertaining to the
optical imaging system according to the fifth embodiment of the
invention.
[0039] FIG. 25 shows aspheric parameters pertaining to the optical
imaging system according to the fifth embodiment of the
invention.
[0040] FIG. 26 is a schematic view illustrating an optical imaging
system according to a sixth embodiment of the invention.
[0041] FIG. 27A to FIG. 27D illustrate a longitudinal spherical
aberration and other aberrations of the optical imaging system
according to the sixth embodiment of the invention.
[0042] FIG. 28 shows detailed optical data pertaining to the
optical imaging system according to the sixth embodiment of the
invention.
[0043] FIG. 29 shows aspheric parameters pertaining to the optical
imaging system according to the sixth embodiment of the
invention.
[0044] FIG. 30 is a schematic view illustrating an optical imaging
system according to a seventh embodiment of the invention.
[0045] FIG. 31A to FIG. 31D illustrate a longitudinal spherical
aberration and other aberrations of the optical imaging system
according to the seventh embodiment of the invention.
[0046] FIG. 32 shows detailed optical data pertaining to the
optical imaging system according to the seventh embodiment of the
invention.
[0047] FIG. 33 shows aspheric parameters pertaining to the optical
imaging system according to the seventh embodiment of the
invention.
[0048] FIG. 34 is a schematic view illustrating an optical imaging
system according to an eighth embodiment of the invention.
[0049] FIG. 35A to FIG. 35D illustrate a longitudinal spherical
aberration and other aberrations of the optical imaging system
according to the eighth embodiment of the invention.
[0050] FIG. 36 shows detailed optical data pertaining to the
optical imaging system according to the eighth embodiment of the
invention.
[0051] FIG. 37 shows aspheric parameters pertaining to the optical
imaging system according to the eighth embodiment of the
invention.
[0052] FIG. 38 to FIG. 41 show important parameters and relation
values thereof pertaining to the optical imaging system according
to the first through the embodiments of the invention.
DESCRIPTION OF EMBODIMENTS
[0053] Reference will now be made in detail to the present
preferred embodiments of the invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers are used in the drawings and the description
to refer to the same or like parts.
[0054] In the present specification, the description "a lens
element having positive refracting power (or negative refracting
power)" means that the paraxial refracting power of the lens
element in Gaussian optics is positive (or negative). The
description "An object-side (or image-side) surface of a lens
element" only includes a specific region of that surface of the
lens element where imaging rays are capable of passing through that
region, namely the clear aperture of the surface. The
aforementioned imaging rays can be classified into two types, chief
ray Lc and marginal ray Lm. Taking a lens element depicted in FIG.
1 as an example, the lens element is rotationally symmetric, where
the optical axis I is the axis of symmetry. The region A of the
lens element is defined as "a portion in a vicinity of the optical
axis", and the region C of the lens element is defined as "a
portion in a vicinity of a periphery of the lens element". Besides,
the lens element may also have an extending portion E extended
radially and outwardly from the region C, namely the portion
outside of the clear aperture of the lens element. The extending
portion E is usually used for physically assembling the lens
element into an optical imaging lens system. Under normal
circumstances, the imaging rays would not pass through the
extending portion E because those imaging rays only pass through
the clear aperture. The structures and shapes of the aforementioned
extending portion E are only examples for technical explanation,
the structures and shapes of lens elements should not be limited to
these examples. Note that the extending portions of the lens
element surfaces depicted in the following embodiments are
partially omitted.
[0055] The following criteria are provided for determining the
shapes and the portions of lens element surfaces set forth in the
present specification. These criteria mainly determine the
boundaries of portions under various circumstances including the
portion in a vicinity of the optical axis, the portion in a
vicinity of a periphery of a lens element surface, and other types
of lens element surfaces such as those having multiple
portions.
[0056] 1. FIG. 1 is a radial cross-sectional view of a lens
element. Before determining boundaries of those aforesaid portions,
two referential points should be defined first, central point and
transition point. The central point of a surface of a lens element
is a point of intersection of that surface and the optical axis.
The transition point is a point on a surface of a lens element,
where the tangent line of that point is perpendicular to the
optical axis. Additionally, if multiple transition points appear on
one single surface, then these transition points are sequentially
named along the radial direction of the surface with numbers
starting from the first transition point. For instance, the first
transition point (closest one to the optical axis), the second
transition point, and the Nth transition point (farthest one to the
optical axis within the scope of the clear aperture of the
surface). The portion of a surface of the lens element between the
central point and the first transition point is defined as the
portion in a vicinity of the optical axis. The portion located
radially outside of the Nth transition point (but still within the
scope of the clear aperture) is defined as the portion in a
vicinity of a periphery of the lens element. In some embodiments,
there are other portions existing between the portion in a vicinity
of the optical axis and the portion in a vicinity of a periphery of
the lens element; the numbers of portions depend on the numbers of
the transition point(s). In addition, the radius of the clear
aperture (or a so-called effective radius) of a surface is defined
as the radial distance from the optical axis I to a point of
intersection of the marginal ray Lm and the surface of the lens
element.
[0057] 2. Referring to FIG. 2, determining the shape of a portion
is convex or concave depends on whether a collimated ray passing
through that portion converges or diverges. That is, while applying
a collimated ray to a portion to be determined in terms of shape,
the collimated ray passing through that portion will be bended and
the ray itself or its extension line will eventually meet the
optical axis. The shape of that portion can be determined by
whether the ray or its extension line meets (intersects) the
optical axis (focal point) at the object-side or image-side. For
instance, if the ray itself intersects the optical axis at the
image side of the lens element after passing through a portion,
i.e. the focal point of this ray is at the image side (see point R
in FIG. 2), the portion will be determined as having a convex
shape. On the contrary, if the ray diverges after passing through a
portion, the extension line of the ray intersects the optical axis
at the object side of the lens element, i.e. the focal point of the
ray is at the object side (see point M in FIG. 2), that portion
will be determined as having a concave shape. Therefore, referring
to FIG. 2, the portion between the central point and the first
transition point has a convex shape, the portion located radially
outside of the first transition point has a concave shape, and the
first transition point is the point where the portion having a
convex shape changes to the portion having a concave shape, namely
the border of two adjacent portions. Alternatively, there is
another common way for a person with ordinary skill in the art to
tell whether a portion in a vicinity of the optical axis has a
convex or concave shape by referring to the sign of an "R" value,
which is the (paraxial) radius of curvature of a lens surface. The
R value which is commonly used in conventional optical design
software such as Zemax and CodeV. The R value usually appears in
the lens data sheet in the software. For an object-side surface,
positive R means that the object-side surface is convex, and
negative R means that the object-side surface is concave.
Conversely, for an image-side surface, positive R means that the
image-side surface is concave, and negative R means that the
image-side surface is convex. The result found by using this method
should be consistent as by using the other way mentioned above,
which determines surface shapes by referring to whether the focal
point of a collimated ray is at the object side or the image
side.
[0058] 3. For none transition point cases, the portion in a
vicinity of the optical axis is defined as the portion between
0.about.50% of the effective radius (radius of the clear aperture)
of the surface, whereas the portion in a vicinity of a periphery of
the lens element is defined as the portion between 50.about.100% of
effective radius (radius of the clear aperture) of the surface.
[0059] Referring to the first example depicted in FIG. 3, only one
transition point, namely a first transition point, appears within
the clear aperture of the image-side surface of the lens element.
Portion I is a portion in a vicinity of the optical axis, and
portion II is a portion in a vicinity of a periphery of the lens
element. The portion in a vicinity of the optical axis is
determined as having a concave surface due to the R value at the
image-side surface of the lens element is positive. The shape of
the portion in a vicinity of a periphery of the lens element is
different from that of the radially inner adjacent portion, i.e.
the shape of the portion in a vicinity of a periphery of the lens
element is different from the shape of the portion in a vicinity of
the optical axis; the portion in a vicinity of a periphery of the
lens element has a convex shape.
[0060] Referring to the second example depicted in FIG. 4, a first
transition point and a second transition point exist on the
object-side surface (within the clear aperture) of a lens element.
In which portion I is the portion in a vicinity of the optical
axis, and portion III is the portion in a vicinity of a periphery
of the lens element. The portion in a vicinity of the optical axis
has a convex shape because the R value at the object-side surface
of the lens element is positive. The portion in a vicinity of a
periphery of the lens element (portion III) has a convex shape.
What is more, there is another portion having a concave shape
existing between the first and second transition point (portion
II).
[0061] Referring to a third example depicted in FIG. 5, no
transition point exists on the object-side surface of the lens
element. In this case, the portion between 0.about.50% of the
effective radius (radius of the clear aperture) is determined as
the portion in a vicinity of the optical axis, and the portion
between 50.about.100% of the effective radius is determined as the
portion in a vicinity of a periphery of the lens element. The
portion in a vicinity of the optical axis of the object-side
surface of the lens element is determined as having a convex shape
due to its positive R value, and the portion in a vicinity of a
periphery of the lens element is determined as having a convex
shape as well.
[0062] FIG. 6 is a schematic view illustrating an optical imaging
system according to a first embodiment of the invention, and FIG.
7A to FIG. 7D illustrate a longitudinal spherical aberration and
other aberrations of the optical imaging system according to the
first embodiment of the invention. Referring to FIG. 6 first, an
optical imaging system 10 of the first embodiment of the invention
includes a reflector 8, a first lens element 3, a second lens
element 4, a third lens element 5, a fourth lens element 6, a fifth
lens element 7 and a filter 9 in order along an optical axis I of
the optical imagining system 10 from an object side to an image
side. After rays emitted by an object to be photographed entering
the optical imaging system 10 from an light inlet 11 and being
sequentially reflected by the reflector 8 and passes through the
first lens element 3, the second lens element 4, the third lens
element 5, the fourth lens element 6, the fifth lens element 7 and
the filter 9, an image is formed on an image plane 100. The light
inlet 11 is located between the object side and the reflector 8.
The filter 9 is, for example, an infrared cut-off filter used to
block infrared light contained in the rays emitted by the object.
It is to be additionally mentioned that the object side faces
towards the object to be photographed, and the image side faces
towards the image plane 100.
[0063] In the present embodiment, the optical axis I includes a
first optical axis I1 and a second optical axis I2 not coinciding
with the first optical axis I1. In the present embodiment, the
optical axis I is bent by a reflective surface 81 of the reflector
8. The first optical axis I1 is a portion of the optical axis I
before being bent by the reflector 8, and the second optical axis
I2 is another portion of the optical axis I after being bent by the
reflector 8. A ray transmitted along the first optical axis I1 is
reflected by the reflective surface 81 and then transmitted along
the second optical axis I2. Namely, the first optical axis I1 and
the second optical axis I2 intersect at an intersection point IP on
the reflective surface 81 of the reflector 8. In the present
embodiment, the lens elements of the optical imaging system 10
which have refractive powers are only disposed on the second
optical axis I2. In the present embodiment, the first lens element
3, the second lens element 4, the third lens element 5, the fourth
lens element 6 and the fifth lens element 7 are arranged in order
from the object side to the image side along the second optical
axis I2 and each has a radius of the clear aperture (i.e., half of
a diameter of the clear aperture) less than or equal to 2.5 mm. In
the present embodiment, the reflector 8 is a prism and has a
light-entering surface 82, the reflective surface 81 and a
light-emitting surface 83. The ray from the light inlet 11 entering
the prism through the light-entering surface 82 is reflected by the
reflective surface 81, then emitted from the prism through the
light-emitting surface 83 and transmitted to the first lens element
3. However, in other embodiments, the reflector 8 may also be a
mirror or other adaptive reflective elements, and a position where
a reflective surface of the mirror is disposed may be the same as a
position where the reflective surface 81 of the prism (i.e., the
reflector 8) is disposed.
[0064] The first lens element 3, the second lens element 4, the
third lens element 5, the fourth lens element 6, the fifth lens
element 7 and the filter 9 respectively have object-side surfaces
31, 41, 51, 61, 71 and 91 facing towards the object side and
allowing imaging rays to pass through and image-side surfaces 32,
42, 52, 62, 72 and 92 facing towards the image side and allowing
the imaging rays to pass through.
[0065] In the present embodiment, in order to satisfy demands for
product miniaturization, the first lens element 3 to the fifth lens
element 7 all have refractive powers, and the first lens element 3,
the second lens element 4, the third lens element 5, the fourth
lens element 6 and the fifth lens element 7 are all made of a
plastic material, namely, a material of the lens elements is a
plastic material, but the material of the first lens element 3 to
the fifth lens element 7 is not limited thereto.
[0066] The first lens element 3 has a positive refractive power. An
object-side surface 31 of the first lens element 3 has a convex
portion 311 in a vicinity of the optical axis I and a convex
portion 313 in a vicinity of a periphery of the first lens element
3. An image-side surface 32 of the first lens element 3 has a
concave portion 322 in the vicinity of the optical axis I and a
concave portion 324 in the vicinity of the periphery of the first
lens element 3.
[0067] The second lens element 4 has a negative refractive power.
The object-side surface 41 of the second lens element 4 has a
convex portion 411 in the vicinity of the optical axis I and a
convex portion 413 in the vicinity of the periphery of the second
lens element 4. An image-side surface 42 of the second lens element
4 has a concave portion 422 in the vicinity of the optical axis I
and a concave portion 424 in the vicinity of the periphery of the
second lens element 4.
[0068] The third lens element 5 has a positive refractive power. An
object-side surface 51 of the third lens element 5 has a convex
portion 511 in the vicinity of the optical axis I and a convex
portion 513 in the vicinity of the periphery of the third lens
element 5. An image-side surface 52 of the third lens element 5 has
a concave portion 522 in the vicinity of the optical axis I and a
concave portion 524 in the vicinity of the periphery of the third
lens element 5.
[0069] The fourth lens element 6 has a negative refractive power.
An object-side surface 61 of the fourth lens element 6 has a
concave portion 612 in the vicinity of the optical axis I and a
concave portion 614 in the vicinity of the periphery of the fourth
lens element 6. An image-side surface 42 of the fourth lens element
6 has a convex portion 621 in the vicinity of the optical axis I
and a concave portion 624 in the vicinity of the periphery of the
fourth lens element 6.
[0070] The fifth lens element 7 has a positive refractive power. An
object-side surface 71 of the fifth lens element 7 has a convex
portion 711 in the vicinity of the optical axis I and a concave
portion 714 in the vicinity of the periphery. An image-side surface
72 of the fifth lens element 7 has a concave portion 722 in the
vicinity of the optical axis I and a convex portion 723 in the
vicinity of the periphery of the fifth lens element 7.
[0071] Additionally, in the present embodiment, only the
aforementioned lens elements have refractive powers, and only 5
lens elements of the optical imaging system 10 have the refractive
powers. However, in other embodiments, other lens elements having
refractive powers may also be disposed along the second optical
axis I2, and the number of the lens elements of the optical imaging
system 10 which have the refractive powers may be more than 5.
[0072] The optical imaging system 10 may further include an
aperture stop 2 disposed between the reflector 8 and the third lens
element 5. In the present embodiment, the aperture stop 2 is
located between the second lens element 4 and the third lens
element 5. However, in other embodiments, the aperture stop 2 may
be located between the reflector 8 and the first lens element 3, or
between the first lens element 3 and the second lens element 4.
[0073] Other detailed optical data of the first embodiment is
illustrated in FIG. 8, and in the first embodiment, an effective
focal length (EFL) of the optical imaging system 10 is 7.614 mm, a
half field of view (HFOV) is 16.799.degree., an f-number (Fno) is
2.420, a system length (TTL) is 7.528 mm, and an image height
(ImgH) is 2.331 mm. The TTL refers to a distance from the
object-side surface 31 of the first lens element 3 to the image
plane 100 along the second optical axis I2. In FIG. 8, the
"Semi-diameter" refers to a radius of the clear aperture of the
object-side surface 31, 41, 51, 61, 71 or the image-side surface
32, 42, 52, 62, 72, and the "Semi-diameter" in the optical data
charts of a second to an eight embodiments physically means the
same.
[0074] In the present embodiment, an included angle between a
normal line of the reflective surface 81 and the first optical axis
I1 is 45.degree., an included angle between the normal line of the
reflective surface 81 and the second optical axis I2 is 45.degree..
The normal line of the reflective surface 81, the first optical
axis I1 and the second optical axis I2 are co-planar, and an
included angle between the first optical axis I1 and the second
optical axis I2 is 90.degree.. However, in other embodiments, the
included angle between the first optical axis I1 and the second
optical axis I2 may be less than 90.degree. or more than
90.degree..
[0075] Additionally, in the present embodiment, the object-side
surfaces 31, 41, 51, 61 and 71 and the image-side surfaces 32, 42,
52, 62 and 72 of the first lens element 3, the second lens element
4, the third lens element 5, the fourth lens element 6 and the
fifth lens element 7, which are 8 surfaces in total, are all
aspheric surfaces, and the aspheric surfaces are defined by the
following formula:
Z ( Y ) = Y 2 R / ( 1 + 1 - ( 1 + K ) Y 2 R 2 ) + i = 1 n a 1
.times. Y i , ( 1 ) ##EQU00001##
[0076] wherein:
[0077] Y: a distance from a point on an aspheric curve to the
second optical axis I2;
[0078] Z: a depth of the aspheric surface (i.e. a perpendicular
distance between the point on the aspheric surface that is spaced
by the distance Y from the second optical axis I2 and a tangent
plane tangent to a vertex of the aspheric surface along the second
optical axis I2);
[0079] R: a radius of curvature of the surface of the lens element
near the second optical axis I2;
[0080] K: a conic constant;
[0081] a.sub.1: the i.sup.th aspheric coefficient.
[0082] The aspheric coefficients of the object-side surfaces 31,
41, 51, 61 and 71 and the image-side surfaces 32, 42, 52, 62 and 72
in formula (1) are shown in FIG. 9. Therein, column No. 31 in FIG.
9 represents the aspheric coefficient of the object-side surface 31
of the first lens element 3, and the other columns may be derived
in the same way.
[0083] In addition, the relations among important parameters
pertaining to the optical imaging system 10 in the first embodiment
are shown in FIG. 38 and FIG. 39.
[0084] Therein,
[0085] T1 represents a thickness of the first lens element 3 along
the second optical axis I2;
[0086] T2 represents a thickness of the second lens element 4 along
the second optical axis I2;
[0087] T3 represents a thickness of the third lens element 5 along
the second optical axis I2;
[0088] T4 represents a thickness of the fourth lens element 6 along
the second optical axis I2;
[0089] T5 represents a thickness of the fifth lens element 7 along
the second optical axis I2;
[0090] TF represents a thickness of the filter 9 along the second
optical axis I2;
[0091] OP1 represents a distance from the light inlet 11 to the
intersection point IP of the first optical axis I1 and the second
optical axis I2 along the first optical axis I1;
[0092] OP2 represents a distance from the intersection point IP of
the first optical axis I1 and the second optical axis I2 to the
image plane 100 of the optical imaging system 10 along the second
optical axis I2;
[0093] G12 represents a distance from the image-side surface 32 of
the first lens element 3 to the object-side surface 41 of the
second lens element 4 along the second optical axis I2, i.e., an
air gap from the first lens element 3 to the second lens element 4
along the second optical axis I2;
[0094] G23 represents a distance from the image-side surface 42 of
the second lens element 4 to the object-side surface 51 of the
third lens element 5 along the second optical axis I2, i.e., an air
gap from the second lens element 4 to the third lens element 5
along the second optical axis I2;
[0095] G34 represents a distance from the image-side surface 52 of
the third lens element 5 to the object-side surface 61 of the
fourth lens element 6 along the second optical axis I2, i.e., an
air gap from the third lens element 5 to the fourth lens element 6
along the second optical axis I2;
[0096] G45 represents a distance from the image-side surface 62 of
the fourth lens element 6 to the object-side surface 71 of the
fifth lens element 7 along the second optical axis I2, i.e., an air
gap from the fourth lens element 6 to the fifth lens element 7
along the second optical axis I2;
[0097] G5F represents a distance from the image-side surface 72 of
the fifth lens element 7 to the object-side surface 91 of the
filter 9 along the second optical axis I2, i.e., an air gap from
the fifth lens element 7 to the filter 9 along the second optical
axis I2;
[0098] GFP represents a distance from the image-side surface 92 of
the filter 9 to the image plane 100 along the second optical axis
I2, i.e., an air gap from the filter 9 to the image plane 100 along
the second optical axis I2;
[0099] AAG represents a sum of the four air gaps from the first
lens element 3 to the fifth lens element 7 along the second optical
axis I2, i.e., a sum of G12, G23, G34 and G45;
[0100] ALT represents a sum of the thicknesses of the first lens
element 3, the second lens element 4, the third lens element 5, the
fourth lens element 6 and the fifth lens element 7 along the second
optical axis I2, i.e., a sum of T1, T2, T3, T4 and T5;
[0101] TTL represents a distance from the object-side surface 31 of
the first lens element 3 to the image plane 100 along the second
optical axis I2;
[0102] TL represents a distance of the object-side surface 31 of
the first lens element 3 to the image-side surface 72 of the fifth
lens element 7 along the second optical axis I2;
[0103] BFL represents a distance from the image-side surface 72 of
the fifth lens element 7 to the image plane 100 along the second
optical axis I2;
[0104] EFL represents an effective focal length of the optical
imaging system 10;
[0105] ImgH represents an image height of the optical imaging
system 10;
[0106] Fno represents an f-number of the optical imaging system 10;
and
[0107] Depth represents a lens depth, i.e., a distance in a
direction along the first optical axis I1 from the light inlet 11
to a position P of the aforementioned optical elements which is
farthest away from the light inlet 11 in a direction parallel to
the first optical axis I1, in brief, a distance from the light
inlet 11 to the position P in a direction along the first optical
axis I1. The position P may be located on the top edge of the
reflector 8, the first lens element 3, the second lens element 4,
the third lens element 5, the fourth lens element 6, the fifth lens
element 7, the filter 9 or the image plane 100 in the figure as
long as this position is farthest away from the light inlet 11
along the first optical axis I1. In the first to the eight
embodiments, the position P may be located on the top edge of the
image plane 100 in the figure, and in this circumstance, the value
of the lens depth Depth is related to the values of OP 1 and
ImgH.
[0108] In addition, it is defined that:
[0109] f1 represents a focal length of the first lens element
3;
[0110] f2 represents a focal length of the second lens element
4;
[0111] f3 represents a focal length of the third lens element
5;
[0112] f4 represents a focal length of the fourth lens element
6;
[0113] f5 represents a focal length of the fifth lens element
7;
[0114] n1 represents an index of refraction of the first lens
element 3;
[0115] n2 represents an index of refraction of the second lens
element 4;
[0116] n3 represents an index of refraction of the third lens
element 5;
[0117] n4 represents an index of refraction of the fourth lens
element 6;
[0118] n5 represents an index of refraction of the fifth lens
element 7;
[0119] .nu.1 represents an Abbe number of the first lens element 3,
wherein the Abbe number may also be referred to as coefficient of
dispersion;
[0120] .nu.2 represents an Abbe number of the second lens element
4;
[0121] .nu.3 represents an Abbe number of the third lens element
5;
[0122] .nu.4 represents an Abbe number of the fourth lens element
6; and
[0123] .nu.5 represents an Abbe number of the fifth lens element
7.
[0124] Referring further to FIG. 7A to FIG. 7D, FIG. 7A illustrates
a longitudinal spherical aberration of the first embodiment when a
pupil radius thereof is 1.5731 mm, FIG. 7B and FIG. 7C respectively
illustrate the field curvature in the sagittal direction and the
field curvature in the tangential direction on the image plane 100
of the first embodiment when the wavelengths thereof are 650 nm,
555 nm, and 470 nm, and FIG. 7D, and FIG. 7D illustrates the
distortion aberration on the image plane 100 of the first
embodiment when the wavelengths thereof are 650 nm, 555 nm, and 470
nm. In the longitudinal spherical aberration figure of FIG. 7A of
the first embodiment, the curves formed by various wavelengths are
all very close and are in a vicinity of the center, which indicates
that off-axis rays at different heights of each wavelength are all
concentrated in a vicinity of imaging point and it can be seen from
the deflection amplitude of the curve of each wavelength that the
imaging point deviation of the off-axis rays at different heights
is controlled within a range of .+-.23 microns, and therefore, in
the present embodiment, the spherical aberration of the same
wavelength is indeed significantly improved. Moreover, the
distances between the three representative wavelengths are also
relatively close, which indicates that the imaging positions of
different wavelength rays are substantially concentrated, and
therefore, the chromatic aberration is also significantly
improved.
[0125] In the two field curvature figures of FIG. 7B and FIG. 7C,
the focal length variation amount of the three representative
wavelengths in the entire field of view is within a range of .+-.55
microns, which indicates that the optical system of the first
embodiment can effectively eliminate aberrations. The distortion
aberration figure of FIG. 7D shows that the distortion aberration
of the first embodiment is maintained within a range of .+-.1.55%,
which indicates that the distortion aberration of the first
embodiment satisfies the imaging quality requirements of the
optical system, and accordingly, by comparing the first embodiment
with the current optical lens, the first embodiment still can
provide preferable imaging quality in the condition that the TTL is
reduced to about 7.528 mm. Therefore, in the first embodiment, the
lens depth and the TTL can be reduced, and the effective focal
length of the optical imaging system 10 can be increased in the
condition that the preferable optical performance is maintained,
thereby achieving a telephoto effect. Additionally, in the optical
imaging system 10 of the present embodiment, the light path is bent
by means of the disposition of the reflector 8, such that the lens
depth can be reduced to meet the design of the portable electronic
products developed toward the goal of miniaturization, thereby
enabling the thinned portable electronic product to be equipped
with a telephoto lens.
[0126] FIG. 10 is a schematic of an optical imaging system of a
second embodiment of the invention, and FIG. 11A to FIG. 11D are
diagrams of the longitudinal spherical aberration and various
aberrations of the optical imaging lens of the second embodiment.
Referring first to FIG. 10, the second embodiment of the optical
imaging system 10 of the invention is substantially similar to the
first embodiment, and the difference therebetween is as follows.
The optical data, the aspheric coefficients, and the parameters of
the lens elements 3, 4, 5, 6 and 7 may be somewhat different.
Moreover, in the present embodiment, the image-side surface 52 of
the third lens element 5 has a convex portion 521 in the vicinity
of the optical axis I and a convex portion 523 in the vicinity of
the periphery of the third lens element 5. The image-side surface
62 of the fourth lens element 6 has a convex portion 621 in the
vicinity of the optical axis I and a convex portion 623 in the
vicinity of the periphery of the fourth lens element 6. It should
be noted here that, in order to clearly show the figure, a portion
of the reference numerals of the same concave portion and convex
portion as the first embodiment is omitted in FIG. 10.
[0127] The detailed optical data of the optical imaging system 10
is as shown in FIG. 12, and in the second embodiment, the EFL of
the optical imaging system 10 is 9.677 mm, the HFOV is
16.000.degree., the Fno is 2.420, the TTL is 9.721 mm, and the ImgH
is 2.805 mm.
[0128] FIG. 13 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, 61 and 71 and the image-side
surfaces 32, 42, 52, 62 and 72 of the second embodiment in formula
(1).
[0129] Additionally, the relationship between each of the important
parameters pertaining to the optical imaging system 10 of the
second embodiment is as shown in FIG. 38 and FIG. 39.
[0130] In the longitudinal spherical aberration figure of FIG. 11A
of the second embodiment in the condition that the pupil radius
thereof is 1.9993 mm, the imaging point deviation of off-axis rays
at different heights is controlled within a range of .+-.22
microns. In the two field curvature aberration figures of FIG. 11B
and FIG. 11C, the focal length variation amount of the three
representative wavelengths in the entire field of view falls within
a range of .+-.70 microns. The distortion aberration figure of FIG.
11D shows that the distortion aberration of the second embodiment
is maintained within a range of .+-.1.2%. Accordingly, by comparing
the second embodiment with the current optical lens, the second
embodiment still can provide preferable imaging quality in the
condition that the TTL is reduced to about 9.721 mm.
[0131] It can be known from the above that the advantages of the
second embodiment in comparison with the first embodiment are: the
HFOV of the second embodiment is less than that of the first
embodiment, which facilitates increasing the telephoto properties,
the longitudinal aberration of the second embodiment is less than
that of the first embodiment, and the distortion of the second
embodiment is less than that of the first embodiment. In addition,
as the difference of the thicknesses of the lens elements in the
vicinity of the optical axis I and the thicknesses of the lens
elements in the vicinity of the periphery in the second embodiment
is smaller than that in the first embodiment, the second embodiment
is easier to be manufactured than the first embodiment and thus,
has a better yield rate.
[0132] FIG. 14 is a schematic view illustrating an optical imaging
system according to a third embodiment of the invention, and FIG.
15A to FIG. 15D illustrate a longitudinal spherical aberration and
other aberrations of the optical imaging system according to the
third embodiment of the invention. Referring to FIG. 14 first, the
third embodiment of the optical imaging system 10 of the invention
is substantially similar to the first embodiment, and the
difference is described as follows. The optical data, the aspheric
coefficients, and the parameters of the lens elements 3, 4, 5, 6
and 7 may be somewhat different. Additionally, in the present
embodiment, the image-side surface 52 of the third lens element 5
has a convex portion 521 in the vicinity of the optical axis I and
a convex portion 523 in the vicinity of the periphery of the third
lens element 5. The image-side surface 62 of the fourth lens
element 6 has a convex portion 621 in the vicinity of the optical
axis I and a convex portion 623 in the vicinity of the periphery of
the fourth lens element 6. Moreover, the fifth lens element 7 has a
negative refractive power. It should be noted here that, in order
to clearly show the figure, a portion of the reference numerals of
the same concave portion and convex portion as the first embodiment
is omitted in FIG. 14.
[0133] The detailed optical data of the optical imaging system 10
is as shown in FIG. 16, and in the third embodiment, the EFL of the
optical imaging system 10 is 10.504 mm, the HFOV is 15.998.degree.,
the Fno is 2.627, the TTL is 12.542 mm, and the ImgH is 2.795
mm.
[0134] FIG. 17 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, 61 and 71 and the image-side
surfaces 32, 42, 52, 62 and 72 of the third embodiment in formula
(1).
[0135] Additionally, the relationship between each of the important
parameters pertaining to the optical imaging system 10 of the third
embodiment is as shown in FIG. 38 and FIG. 39.
[0136] In the longitudinal spherical aberration figure of FIG. 15A
of the third embodiment in the condition that the pupil radius
thereof is 1.9990 mm, the imaging point deviation of off-axis rays
at different heights is controlled within a range of .+-.40
microns. In the two field curvature aberration figures of FIG. 15B
and FIG. 15C, the focal length variation amount of the three
representative wavelengths in the entire field of view falls within
a range of .+-.180 microns. The distortion aberration figure of
FIG. 15D shows that the distortion aberration of the third
embodiment is maintained within a range of .+-.7.5%. Accordingly,
by comparing the third embodiment with the current optical lens,
the third embodiment still can provide preferable imaging quality
in the condition that the TTL is reduced to about 12.542 mm.
[0137] It can be known from the above that the advantages of the
third embodiment in comparison with the first embodiment are: the
HFOV of the third embodiment is less than that of the first
embodiment, which facilitates increasing the telephoto properties,
and as the difference of the thicknesses of the lens elements in
the vicinity of the optical axis I and the thicknesses of the lens
elements in the vicinity of the periphery is smaller, the third
embodiment is easier to be manufactured than the first embodiment
and thus, has a better yield rate.
[0138] FIG. 18 is a schematic view illustrating an optical imaging
system according to a fourth embodiment of the invention, and FIG.
19A to FIG. 19D illustrate a longitudinal spherical aberration and
other aberrations of the optical imaging system according to the
fourth embodiment of the invention. Referring to FIG. 18 first, the
fourth embodiment of the optical imaging system 10 of the invention
is substantially similar to the first embodiment, and the
difference is described as follows. The optical data, the aspheric
coefficients, and the parameters of the lens elements 3, 4, 5, 6
and 7 may be somewhat different. Additionally, in the present
embodiment, the image-side surface 52 of the third lens element 5
has a concave portion 522 in the vicinity of the optical axis I and
a convex portion 523 in the vicinity of the periphery of the third
lens element 5. The fifth lens element 7 has a negative refractive
power. The object-side surface 71 of the fifth lens element 7 has a
concave portion 712 in the vicinity of the optical axis I and a
concave portion 714 in the vicinity of the periphery of the fifth
lens element 7. Moreover, in the present embodiment, the image-side
surface 72 of the fifth lens element 7 has a convex portion 721 in
the vicinity of the optical axis I and a convex portion 723 in the
vicinity of the periphery of the fifth lens element 7. It should be
noted here that, in order to clearly show the figure, a portion of
reference numerals of the same concave portion and convex portion
as the first embodiment is omitted in FIG. 18. Additionally, in the
present embodiment, light 101 entering from the edge of the light
inlet 11 is incapable of arriving at the reflective surface 81 due
to the specification design of the optical imaging system 10.
[0139] The detailed optical data of the optical imaging system 10
is as shown in FIG. 20, and in the fourth embodiment, the EFL of
the optical imaging system 10 is 10.139 mm, the HFOV is
15.999.degree., the Fno is 2.42, the TTL is 8.411 mm, and the ImgH
is 2.808 mm.
[0140] FIG. 21 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, 61 and 71 and the image-side
surfaces 32, 42, 52, 62 and 72 of the fourth embodiment in formula
(1).
[0141] Additionally, the relationship between each of the important
parameters pertaining to the optical imaging system 10 of the
fourth embodiment is as shown in FIG. 38 and FIG. 39.
[0142] In the longitudinal spherical aberration figure of FIG. 19A
of the fourth embodiment in the condition that the pupil radius
thereof is 2.0948 mm, the imaging point deviation of off-axis rays
at different heights is controlled within a range of .+-.25
microns. In the two field curvature aberration figures of FIG. 19B
and FIG. 19C, the focal length variation amount of the three
representative wavelengths in the entire field of view falls within
a range of .+-.250 microns. The distortion aberration figure of
FIG. 19D shows that the distortion aberration of the fourth
embodiment is maintained within a range of .+-.4.3%. Accordingly,
by comparing the fourth embodiment with the current optical lens,
the fourth embodiment still can provide preferable imaging quality
in the condition that the TTL is reduced to about 8.411 mm.
[0143] It can be known from the above that the advantages of the
fourth embodiment in comparison with the first embodiment are: the
HFOV of the fourth embodiment is less than that of the first
embodiment, which facilitates increasing the telephoto
properties.
[0144] FIG. 22 is a schematic view illustrating an optical imaging
system according to a fifth embodiment of the invention, and FIG.
23A to FIG. 23D illustrate a longitudinal spherical aberration and
other aberrations of the optical imaging system according to the
fifth embodiment of the invention. Referring to FIG. 22 first, the
fifth embodiment of the optical imaging system 10 of the invention
is substantially similar to the first embodiment, and the
difference is described as follows. The optical data, the aspheric
coefficients, and the parameters of the lens elements 3, 4, 5, 6
and 7 may be somewhat different. Additionally, in the present
embodiment, the image-side surface 52 of the third lens element 5
has a convex portion 521 in the vicinity of the optical axis I and
a convex portion 523 in the vicinity of the periphery of the third
lens element 5. It should be noted here that, in order to clearly
show the figure, a portion of reference numerals of the same
concave portion and convex portion as the first embodiment is
omitted in FIG. 22.
[0145] The detailed optical data of the optical imaging system 10
is as shown in FIG. 24, and in the fifth embodiment, the EFL of the
optical imaging system 10 is 8.807 mm, the HFOV is 21.501.degree.,
the Fno is 2.203, the TTL is 9.048 mm, and the ImgH is 3.903
mm.
[0146] FIG. 25 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, 61 and 71 and the image-side
surfaces 32, 42, 52, 62 and 72 of the fifth embodiment in formula
(1).
[0147] Additionally, the relationship between each of the important
parameters pertaining to the optical imaging system 10 of the fifth
embodiment is as shown in FIG. 40 and FIG. 41.
[0148] In the longitudinal spherical aberration figure of FIG. 23A
of the fifth embodiment in the condition that the pupil radius
thereof is 1.9990 mm, the imaging point deviation of off-axis rays
at different heights is controlled within a range of .+-.11.5
microns. In the two field curvature aberration figures of FIG. 23B
and FIG. 23C, the focal length variation amount of the three
representative wavelengths in the entire field of view falls within
a range of .+-.115 microns. The distortion aberration figure of
FIG. 23D shows that the distortion aberration of the fifth
embodiment is maintained within a range of .+-.13%. Accordingly, by
comparing the fifth embodiment with the current optical lens, the
fifth embodiment still can provide preferable imaging quality in
the condition that the TTL is reduced to about 9.048 mm.
[0149] It can be known from the above that the advantages of the
fifth embodiment in comparison with the first embodiment are: the
f-number of the fifth embodiment is smaller than that of the first
embodiment, and the longitudinal aberration of the fifth embodiment
is less than that of the first embodiment. Additionally, as the
difference of the thicknesses of the lens elements in the vicinity
of the optical axis I and the thicknesses of the lens elements in
the vicinity of the periphery in the fifth embodiment is smaller,
the fifth embodiment is easier to be manufactured than the first
embodiment and thus, has a better yield rate.
[0150] FIG. 26 is a schematic view illustrating an optical imaging
system according to a sixth embodiment of the invention, and FIG.
27A to FIG. 27D illustrate a longitudinal spherical aberration and
other aberrations of the optical imaging system according to the
sixth embodiment. Referring to FIG. 26 first, the sixth embodiment
of the optical imaging system 10 of the invention is substantially
similar to the first embodiment, and the difference is described as
follows. The optical data, the aspheric coefficients, and the
parameters of the lens elements 3, 4, 5, 6 and 7 may be somewhat
different. Additionally, in the present embodiment, the image-side
surface 52 of the third lens element 5 has a convex portion 521 in
the vicinity of the optical axis I and has a convex portion 523 in
the vicinity of the periphery of the third lens element 5.
Moreover, in the present embodiment, the aperture stop 2 is located
between the first lens element 3 and the second lens element 4. It
should be noted here that, in order to clearly show the figure, a
portion of reference numerals of the same concave portion and
convex portion as the first embodiment is omitted in FIG. 26.
[0151] The detailed optical data of the optical imaging system 10
is as shown in FIG. 28, and in the sixth embodiment, the EFL of the
optical imaging system 10 is 9.712 mm, the HFOV is 15.998.degree.,
the Fno is 2.420, the TTL is 9.540 mm, and the ImgH is 2.8 mm.
[0152] FIG. 29 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, 61 and 71 and the image-side
surfaces 32, 42, 52, 62 and 72 of the sixth embodiment in formula
(1).
[0153] Additionally, the relationship between each of the important
parameters pertaining to the optical imaging system 10 of the sixth
embodiment is as shown in FIG. 40 and FIG. 41.
[0154] In the longitudinal spherical aberration figure of FIG. 27A
of the sixth embodiment in the condition that the pupil radius
thereof is 2.0065 mm, the imaging point deviation of off-axis rays
at different heights is controlled within a range of .+-.61
microns. In the two field curvature aberration figures of FIG. 27B
and FIG. 27C, the focal length variation amount of the three
representative wavelengths in the entire field of view falls within
a range of .+-.80 microns. The distortion aberration figure of FIG.
27D shows that the distortion aberration of the sixth embodiment is
maintained within a range of .+-.0.9%. Accordingly, by comparing
the sixth embodiment with the current optical lens, the sixth
embodiment still can provide preferable imaging quality in the
condition that the TTL is reduced to about 9.540 mm.
[0155] It can be known from the above that the advantages of the
sixth embodiment in comparison with the first embodiment are: the
HFOV of the sixth embodiment is less than that of the first
embodiment, which facilitates increasing the telephoto properties,
and the distortion of the sixth embodiment is less than that of the
first embodiment. Additionally, as the difference of the
thicknesses of the lens elements in the vicinity of the optical
axis I and the thicknesses of the lens elements in the vicinity of
the periphery in the sixth embodiment is smaller, the sixth
embodiment is easier to be manufactured than the first embodiment
and thus, has a better yield rate.
[0156] FIG. 30 is a schematic view illustrating an optical imaging
system according to a seventh embodiment, and FIG. 31A to FIG. 31D
illustrate a longitudinal spherical aberration and other
aberrations of the optical imaging system according to the seventh
embodiment of the invention. Referring to FIG. 30 first, the
seventh embodiment of the optical imaging system 10 of the
invention is substantially similar to the first embodiment, and the
difference is described as follows. The optical data, the aspheric
coefficients, and the parameters of the lens elements 3, 4, 5, 6
and 7 may be somewhat different. Additionally, in the present
embodiment, the image-side surface 52 of the third lens element 5
has a convex portion 521 in the vicinity of the optical axis I and
a convex portion 523 in the vicinity of the periphery of the third
lens element 5. The image-side surface 72 of the fifth lens element
7 has a convex portion 721 in the vicinity of the optical axis I
and a convex portion 723 in the vicinity of the periphery of the
third lens element 5. It should be noted here that, in order to
clearly show the figure, a portion of reference numerals of the
same concave portion and convex portion as the first embodiment is
omitted in FIG. 30.
[0157] The detailed optical data of the optical imaging system 10
is as shown in FIG. 32, and in the seventh embodiment, the EFL of
the optical imaging system 10 is 9.864 mm, the HFOV is
16.08.degree., the Fno is 2.420, the TTL is 9.654 mm, and the ImgH
is 2.815 mm.
[0158] FIG. 33 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, 61 and 71 and the image-side
surfaces 32, 42, 52, 62 and 72 of the seventh embodiment in formula
(1).
[0159] Additionally, the relationship between each of the important
parameters pertaining to the optical imaging system 10 of the
seventh embodiment is as shown in FIG. 40 and FIG. 41.
[0160] In the longitudinal spherical aberration figure of FIG. 31A
of the seventh embodiment in the condition that the pupil radius
thereof is 2.0379 mm, the imaging point deviation of off-axis rays
at different heights is controlled within a range of .+-.60
microns. In the two field curvature aberration figures of FIG. 31B
and FIG. 31C, the focal length variation amount of the three
representative wavelengths in the entire field of view falls within
a range of .+-.60 microns. The distortion aberration figure of FIG.
31D shows that the distortion aberration of the seventh embodiment
is maintained within a range of .+-.0.47%. Accordingly, by
comparing the seventh embodiment with the current optical lens, the
seventh embodiment still can provide preferable imaging quality in
the condition that the TTL is reduced to about 9.654 mm.
[0161] It can be known from the above that the advantages of the
seventh embodiment in comparison with the first embodiment are: the
HFOV of the seventh embodiment is less than that of the first
embodiment, which facilitates increasing the telephoto properties,
and the distortion of the seventh embodiment is less than that of
the first embodiment. Additionally, as the difference of the
thicknesses of the lens elements in the vicinity of the optical
axis I and the thicknesses of the lens elements in the vicinity of
the periphery in the seventh embodiment is smaller, the seventh
embodiment is easier to be manufactured than the first embodiment
and thus, has a better yield rate.
[0162] FIG. 34 is a schematic view illustrating an optical imaging
system according to an eighth embodiment, and FIG. 35A to FIG. 35D
illustrate a longitudinal spherical aberration and other
aberrations of the optical imaging system according to the eighth
embodiment. Referring to FIG. 34 first, the eighth embodiment of
the optical imaging system 10 of the invention is substantially
similar to the first embodiment, and the difference is described as
follows. The optical data, the aspheric coefficients, and the
parameters of the lens elements 3, 4, 5, 6 and 7 may be somewhat
different. Additionally, in the present embodiment, the image-side
surface 52 of the third lens element 5 has a convex portion 521 in
the vicinity of the optical axis I and a convex portion 523 in the
vicinity of the periphery of the third lens element 5. The
image-side surface 72 of the fifth lens element 7 has a convex
portion 721 in the vicinity of the optical axis I and a convex
portion 723 in the vicinity of the periphery of the fifth lens
element 7. It should be noted here that, in order to clearly show
the figure, a portion of reference numerals of the same concave
portion and convex portion as the first embodiment is omitted in
FIG. 34.
[0163] The detailed optical data of the optical imaging system 10
is as shown in FIG. 36, and in the eighth embodiment, the EFL of
the optical imaging system 10 is 9.940 mm, the HFOV is
16.091.degree., the Fno is 2.420, the TTL is 9.711 mm, and the ImgH
is 2.813 mm.
[0164] FIG. 37 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, 61 and 71 and the image-side
surfaces 32, 42, 52, 62 and 72 of the eighth embodiment in formula
(1).
[0165] Additionally, the relationship between each of the important
parameters pertaining to the optical imaging system 10 of the
eighth embodiment is as shown in FIG. 40 and FIG. 41.
[0166] In the longitudinal spherical aberration figure of FIG. 35A
of the eighth embodiment in the condition that the pupil radius
thereof is 2.0536 mm, the imaging point deviation of off-axis rays
at different heights is controlled within a range of .+-.100
microns. In the two field curvature aberration figures of FIG. 35B
and FIG. 35C, the focal length variation amount of the three
representative wavelengths in the entire field of view falls within
a range of .+-.100 microns. The distortion aberration figure of
FIG. 35D shows that the distortion aberration of the eighth
embodiment is maintained within a range of .+-.1.5%. Accordingly,
by comparing the eighth embodiment with the current optical lens,
the eighth embodiment still can provide preferable imaging quality
in the condition that the TTL is reduced to about 9.711 mm.
[0167] It can be known from the above that the advantages of the
eighth embodiment in comparison with the first embodiment are: the
HFOV of the eighth embodiment is less than that of the first
embodiment, which facilitates increasing the telephoto properties,
the distortion of the eighth embodiment is less than that of the
first embodiment, and as the difference of the thicknesses of the
lens elements in the vicinity of the optical axis I and the
thicknesses of the lens elements in the vicinity of the periphery
in the second embodiment is smaller, the eighth embodiment is
easier to be manufactured than the first embodiment and thus, has a
better yield rate.
[0168] FIG. 38 to FIG. 41 show tables of the optical parameters of
the eight embodiments. Through the arrangement of the below designs
operated with one another, the lens length can be effectively
reduced and ensure imaging quality at the same time, and the
clarity for partially or entirely imaging the object can be
improved.
[0169] 1. The convex portion 311 of the object-side surface 31 of
the first lens element 3 presenting in the vicinity of the optical
axis I can facilitate collecting the imaging rays and can achieve a
better effect when the first lens element 3 having the positive
refractive power is selectively equipped therewith. The second lens
element 4 made of the plastic material contributes to the reduction
of difficulty and cost in the fabrication and assembly. The convex
portion 521 or the concave portion 522 of the image-side surface 52
of the third lens element 5 in the vicinity of the optical axis I
facilitate increasing imaging quality. At least one of the
object-side surface 61 and the image-side surface 62 of the fourth
lens element 6 being an aspheric surface and the object-side
surface 71 and the image-side surface 72 of the fifth lens element
7 being aspheric surfaces can contribute to the correction of
optical aberrations, such as image distortion, chromatic
aberration, coma and so on, thereby not only improving the
imagining quality of the optical imaging system, but also reducing
the number of the lens elements of the optical imaging system
10.
[0170] 2. The aperture stop 2 located between the reflector 8 and
the first lens element 3 can facilitate effectively reducing the
lens length, and the aperture stop 2 located between the first lens
element 3 and the second lens element 4 or between the second lens
element 4 and the third lens element 5 can be favorable for
reducing the f-number (Fno) without increasing the radius of the
clear aperture of each of the lens elements, such that the radius
of the clear aperture of each of the lens elements is less than or
equal to 2.5 mm, and 7.5 mm.ltoreq.EFL.ltoreq.13.5 mm.
[0171] 3. The reflector 8 is selectively arranged on the object
side of the lens element group formed by the first to the fifth
lens elements 3 to 7, and the lens elements with the refractive
powers are only disposed along the second optical axis I2 or
satisfy (OP1/ImgH).times.Fno.ltoreq.3.1, which is favorable for
reducing the lens depth to meet the demands for much thinner
portable electronic products. In order to preferably control the
lens depth, the following conditional formula may be selectively
arranged, where the preferable range is
1.3.ltoreq.(OP1/ImgH).times.Fno.ltoreq.3.1, and the most preferable
range is 1.5.ltoreq.(OP1/ImgH).times.Fno.ltoreq.3.1.
[0172] 4. The second lens element 4 having the negative refractive
power or the image-side surface 42 of the second lens element 4
having the concave portion 422 in the vicinity of the optical axis
may be selectively arranged for eliminating the aberration
generated by the first lens element 3. The object-side surface 61
of the fourth lens element 6 having the concave portion 614 in the
vicinity of the periphery or the image-side surface 72 of the fifth
lens element 7 having the convex portion 724 in the vicinity of the
periphery may be selectively arranged to effectively correct the
aberration of local image of the object.
[0173] When the relation among the optical parameters of the
optical imaging lens 10 in the embodiments of the invention
satisfies at least one of the following conditional formulas, or
the optical imaging system 10 has at least one of the following
features, it assists a designer to design a technically feasible
optical imaging system with preferable optical performance, an
overall length or a lens depth that is effectively reduced.
[0174] 1. In order to achieve reduced lens system length, in the
embodiments of the invention, the lens element thickness and the
air gap between the lens elements are suitably reduced. However,
under the premise of considering the difficulty of the lens
assembly process and achieving imaging quality, the lens element
thickness and the air gap between the lens elements need to be
adjusted together, and therefore by satisfying the numeric value
limitation of the following condition formulas, the optical imaging
system can achieve better configuration:
ALT/(T4+T5).ltoreq.3.5, preferably
1.8.ltoreq.ALT/(T4+T5).ltoreq.3.5, most preferably
2.4.ltoreq.ALT/(T4+T5).ltoreq.3.5;
(G23+T3+G34)/(T1+G12+T2).ltoreq.1.8, preferably
0.6.ltoreq.(G23+T3+G34)/(T1+G12+T2).ltoreq.1.8;
AAG/(G12+G45).ltoreq.5.6, preferably
1.3.ltoreq.AAG/(G12+G45).ltoreq.5.6;
1.2.ltoreq.OP2/ALT.ltoreq.4.9, preferably
1.7.ltoreq.OP2/ALT.ltoreq.4.9;
ALT/BFL.ltoreq.2.5, preferably 0.5.ltoreq.ALT/BFL.ltoreq.2.5;
(G23+T3+G34)/(T4+G45+T5).ltoreq.1.7, preferably
0.3.ltoreq.(G23+T3+G34)/(T4+G45+T5).ltoreq.1.7; and
(G23+T3+G34)/(T4+T5).ltoreq.1.7, preferably
0.8.ltoreq.(G23+T3+G34)/(T4+T5).ltoreq.1.7.
[0175] 2. In order to maintain a ratio of the optical element
parameter to the lens length at a suitable value, satisfying at
least one of the following conditional formulas can facilitate
preventing difficulty in manufacturing due to small parameters or
excessive system length of the lens due to large parameters:
TL/BFL.ltoreq.3.5, preferably 0.8.ltoreq.TL/BFL.ltoreq.3.5;
TTL/(T1+T2+T3).ltoreq.6.0, preferably
1.8.ltoreq.TTL/(T1+T2+T3).ltoreq.6.0, most preferably
1.8.ltoreq.TTL/(T1+T2+T3).ltoreq.5.6;
TL/(T4+T5).ltoreq.4.5, preferably 2.8.ltoreq.TL/(T4+T5).ltoreq.4.5;
and
TL/(T1+G12+T2).ltoreq.4.2, preferably
2.8.ltoreq.TL/(T1+G12+T2).ltoreq.4.2.
[0176] 3. In order to maintain a ratio of the effective focal
length (EFL) to the lens length at a suitable value, satisfying at
least one of the following conditional formulas can facilitate
preventing difficulty in capturing a far object in the lens due to
small parameters, or excessive system length of the lens due to
large parameters:
0.6.ltoreq.OP2/EFL.ltoreq.2.7, preferably
1.0.ltoreq.OP2/EFL.ltoreq.1.6; and
TTL/EFL.ltoreq.1.2, preferably 0.7.ltoreq.TTL/EFL.ltoreq.1.2.
[0177] 4. In order to achieve preferable arrangement of the lens
depth and the lens length, and prevent difficulty in thinning the
portable electronic products due to large lens depths, satisfying
at least one of the following conditional formulas can meet the
demands for thinner products:
2.2.ltoreq.OP2/OP1.ltoreq.8.8, preferably
3.4.ltoreq.OP2/OP1.ltoreq.5.9; and
1.6: TTL/OP1.ltoreq.6.5, preferably
2.3.ltoreq.TTL/OP1.ltoreq.4.7.
[0178] 5. In order to effectively reduce the chromatic aberration
of the optical imaging system 10, satisfying at least one of the
following conditional formulas can facilitate improving imaging
quality:
0.0.ltoreq.|.nu.5-.nu.2|.ltoreq.30.0;
0.0.ltoreq.|.nu.4-.nu.3|.ltoreq.30.0.
[0179] 6. The reflector 8 may be a prism or a mirror, which
satisfies higher demands for thinner portable electronic
products.
[0180] However, in view of unpredictability in optical system
design, under the architectures according to the embodiments of the
invention, satisfying the aforementioned formulas can facilitate
preferably achieving the reduction of the lens length of the
embodiments of the invention, increasing the aperture, improving
the imaging quality, or enhancing the assembly yield rate, thereby
improving disadvantages of the related art.
[0181] Based on the above, the optical imaging system 10 of the
embodiments of the invention may also achieve the following
efficacies and advantages:
[0182] 1. The longitudinal spherical aberration, the field
curvature, and the distortion of each embodiment of the invention
can all satisfy usage criteria. Moreover, the three representative
wavelengths of 650 nm, 555 nm and 470 nm are all concentrated in
the vicinity of the imaging point at different heights of off-axis
rays, and it can be seen from the deflection amplitude of each
curve that the imaging point deviations of off-axis rays at
different heights can be well controlled to have good spherical
aberration and capability to suppress the aberration distortion.
Referring further to the imaging quality data, the distances
between the three representative wavelengths of 650 nm, 555 nm, and
470 nm are also relatively close, which indicates that the
concentration of rays having different wavelengths under various
states in the embodiments of the invention is good and excellent
dispersion reduction capability is achieved, and therefore it can
be known from the above that the embodiments of the invention have
good optical performance.
[0183] 2. In addition, the aforementioned limitation relations are
provided in an exemplary sense and can be randomly and selectively
combined and applied to the embodiments of the invention in
different manners; the invention should not be limited to the above
examples. In implementation of the invention, apart from the
above-described relations, it is also possible to add additional
detailed structure such as more concave and convex curvatures
arrangement of a specific lens element or a plurality of lens
elements so as to enhance control of system property and/or
resolution. It should be noted that the above-described details can
be optionally combined and applied to the other embodiments of the
invention under the condition where they are not in conflict with
one another.
[0184] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
invention covers modifications and variations of this invention
provided they fall within the scope of the following claims and
their equivalents.
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