U.S. patent application number 15/273716 was filed with the patent office on 2018-03-01 for optical imaging lens.
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 Matthew Bone, Maozong Lin, Zhenfeng Xie.
Application Number | 20180059365 15/273716 |
Document ID | / |
Family ID | 58343597 |
Filed Date | 2018-03-01 |
United States Patent
Application |
20180059365 |
Kind Code |
A1 |
Bone; Matthew ; et
al. |
March 1, 2018 |
OPTICAL IMAGING LENS
Abstract
An optical imaging lens includes a first lens element, a second
lens element, a third lens element, and a fourth lens element from
an object side to an image side in order along an optical axis. The
first lens element to the fourth lens element each include an
object-side surface and an image-side surface. The first lens
element has positive refracting power. The second lens element has
negative refracting power. At least one of the object-side surface
and the image-side surface of the third lens element is an aspheric
surface. At least one of the object-side surface and the image-side
surface of the fourth lens element is an aspheric surface. A
maximum distance between the image-side surface of the first lens
element and the object-side surface of the second lens element in a
direction parallel to the optical axis is less than 0.2 mm.
Inventors: |
Bone; Matthew; (Taichung
City, TW) ; Lin; Maozong; (Xiamen, CN) ; Xie;
Zhenfeng; (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: |
58343597 |
Appl. No.: |
15/273716 |
Filed: |
September 23, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 13/004 20130101;
G02B 13/02 20130101; G02B 13/0065 20130101; G02B 27/0025 20130101;
G02B 9/34 20130101 |
International
Class: |
G02B 13/00 20060101
G02B013/00; G02B 9/34 20060101 G02B009/34; G02B 27/00 20060101
G02B027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 25, 2016 |
CN |
201610725556.6 |
Claims
1. An optical imaging lens comprising a front lens group and a rear
lens group from an object side to an image side in order along an
optical axis, the optical axis comprising a first optical axis and
a second optical axis not coinciding with the first optical axis,
the front lens group comprising a first lens element and a second
lens element from the object side to the image side in order along
the first optical axis, the rear lens group comprising a third lens
element and a fourth lens element from the object side to the image
side in order along the second optical axis, wherein the first lens
element to the fourth lens element each comprise an object-side
surface facing the object side and allowing imaging rays to pass
through and an image-side surface facing 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 object side to the image side, the
second lens element is arranged to be a lens element having
refracting power in a second order from the object side to the
image side, the third lens element is arranged to be a lens element
having refracting power in a second order from the image side to
the object side, and the fourth lens element is arranged to be a
lens element having refracting power in a first order from the
image side to the object side; the first lens element has positive
refracting power; the second lens element has negative refracting
power; at least one of the object-side surface and the image-side
surface of the third lens element is an aspheric surface; and at
least one of the object-side surface and the image-side surface of
the fourth lens element is an aspheric surface, wherein a maximum
distance between the image-side surface of the first lens element
and the object-side surface of the second lens element in a
direction parallel to the first optical axis is less than 0.2 mm,
and the optical imaging lens satisfies: 6.1.ltoreq.ImaH/(G12+T2);
T1/T2.ltoreq.3.7; and 0.75.ltoreq.T4/G34.ltoreq.11.8, where ImaH is
an image height of the optical imaging lens, G12 is an air gap from
the first lens element to the second lens element on the first
optical axis, T2 is a thickness of the second lens element on the
first optical axis, T1 is a thickness of the first lens element on
the optical axis, T4 is a thickness of the fourth lens element on
the optical axis, and G34 is an air gap from the third lens element
to the fourth lens element on the optical axis.
2. The optical imaging lens of claim 1, wherein the optical imaging
lens further satisfies: 18.ltoreq.v1-v2.ltoreq.50, where v1 is an
Abbe number of the first lens element, and v2 is an Abbe number of
the second lens element.
3. The optical imaging lens of claim 1, wherein the image-side
surface of the first lens element has a convex portion in a
vicinity of the optical axis.
4. The optical imaging lens of claim 1, wherein the object-side
surface of the second lens element has a concave portion in a
vicinity of the optical axis.
5. The optical imaging lens of claim 1, wherein the optical imaging
lens further satisfies: 1.ltoreq.EFL/fFG.ltoreq.2, where EFL is an
effective focal length of the optical imaging lens, and fFG is a
focal length of the front lens group.
6. The optical imaging lens of claim 1, wherein the optical imaging
lens further satisfies: HFOV.ltoreq.25.degree., where HFOV is a
half field of view of the optical imaging lens.
7. The optical imaging lens of claim 1, wherein the optical imaging
lens further satisfies: TTL/EFL.ltoreq.1.01, where TTL is a
distance from the object-side surface of the first lens element to
an image plane of the optical imaging lens on the optical axis, and
EFL is an effective focal length of the optical imaging lens.
8. The optical imaging lens of claim 1, wherein the optical imaging
lens further satisfies: Depth.ltoreq.6.1 mm, where Depth is a
distance in a direction of the first optical axis from a first
position of the object-side surface of the first lens element
intersecting the first optical axis to a second position of the
optical imaging lens farthest away from the first position in the
direction of the first optical axis.
9. The optical imaging lens of claim 1, wherein at least one of the
object-side surface and the image-side surface of the third lens
element has a transition point.
10. An optical imaging lens comprising a first lens element, a
second lens element, a third lens element, and a fourth lens
element from an object side to an image side in order along an
optical axis, wherein the first lens element to the fourth lens
element each comprise an object-side surface facing the object side
and allowing imaging rays to pass through and an image-side surface
facing 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
object side to the image side, the second lens element is arranged
to be a lens element having refracting power in a second order from
the object side to the image side, the third lens element is
arranged to be a lens element having refracting power in a second
order from the image side to the object side, and the fourth lens
element is arranged to be a lens element having refracting power in
a first order from the image side to the object side; the first
lens element has positive refracting power; the second lens element
has negative refracting power; at least one of the object-side
surface and the image-side surface of the third lens element is an
aspheric surface; and at least one of the object-side surface and
the image-side surface of the fourth lens element is an aspheric
surface, wherein a maximum distance between the image-side surface
of the first lens element and the object-side surface of the second
lens element in a direction parallel to the optical axis is less
than 0.2 mm, and the optical imaging lens satisfies:
6.1.ltoreq.ImaH/(G12+T2); 1.2.ltoreq.G23/EPD; T1/T2.ltoreq.3.7; and
0.75.ltoreq.T4/G34.ltoreq.11.8, where ImaH is an image height of
the optical imaging lens, G12 is an air gap from the first lens
element to the second lens element on the optical axis, T2 is a
thickness of the second lens element on the optical axis, G23 is an
air gap from the second lens element to the third lens element on
the optical axis, and EPD is a diameter of an entrance pupil of the
optical imaging lens, T1 is a thickness of the first lens element
on the optical axis, T4 is a thickness of the fourth lens element
on the optical axis, and G34 is an air gap from the third lens
element to the fourth lens element on the optical axis.
11. (canceled)
12. The optical imaging lens of claim 10, wherein the optical
imaging lens further satisfies: G34/(G12+T2).ltoreq.4.3.
13. The optical imaging lens of claim 10, wherein the optical
imaging lens further satisfies: G23/T2.ltoreq.20.
14. The optical imaging lens of claim 10, wherein the optical
imaging lens further satisfies: AAG/T2.ltoreq.26, where AAG is a
sum of three air gaps from the first lens element to the fourth
lens element on the optical axis.
15. The optical imaging lens of claim 10, wherein the optical
imaging lens further satisfies: EFL/T2.ltoreq.40, where EFL is an
effective focal length of the optical imaging lens.
16. The optical imaging lens of claim 10, wherein the optical
imaging lens further satisfies: 1.ltoreq.T1/G34.ltoreq.32.
17. The optical imaging lens of claim 10, wherein the optical
imaging lens further satisfies: 2.ltoreq.ALT/G34.ltoreq.31, where
ALT is a sum of thicknesses of the first lens element, the second
lens element, the third lens element, and the fourth lens element
on the optical axis.
18. The optical imaging lens of claim 10, wherein the optical
imaging lens further satisfies: 4.ltoreq.G23/G34.ltoreq.62.
19. The optical imaging lens of claim 10, wherein the optical
imaging lens further satisfies: 0.44.ltoreq.T3/G34.ltoreq.6.4,
where T3 is a thickness of the third lens element on the optical
axis.
20. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of China
application serial no. 201610725556.6, filed on Aug. 25, 2016. 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
Field of the Invention
[0002] The invention relates to an optical imaging lens.
Description of Related Art
[0003] In recent years, the popularity of mobile products such as
mobile phones and digital cameras allowed the rigorous development
of imaging module-related techniques, and the imaging module mainly
contains elements such as an optical imaging lens, a module holder
unit, and a sensor, and the thin and light developing trend of
mobile phones and digital cameras also resulted in a greater demand
of the compactness of the imaging module. With the advancement of
the techniques of charge-coupled device (CCD) and complementary
metal oxide semiconductor (CMOS) and reduction in size, the length
of the optical imaging lens installed in the imaging module also
needs to be correspondingly reduced. However, to prevent reduction
in photographic effects and quality, when the length of the optical
imaging lens is reduced, good optical performance still needs to be
achieved. The most important feature of the optical imaging lens is
expectedly imaging quality and size.
[0004] Specifications of mobile products (such as mobile phones,
cameras, tablet computers, personal digital assistants, automotive
video devices, and virtual reality trackers) are ever changing, and
the key component thereof, the optical imaging lens, is also being
more dynamically developed, and the application not only covers
photography and video recording, but also includes, for instance,
environmental monitoring and driving records recording, and with
the advancement of image sensing techniques, consumer demand for,
for instance, imaging quality is also increased.
[0005] However, the optical imaging lens design cannot produce an
optical imaging lens having both imaging quality and small size
simply by reducing the ratio of, for instance, a lens having good
imaging quality, and 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 small 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] Moreover, the larger the focal length of an optical imaging
lens, the larger the magnification of the optical imaging lens. As
a result, the length of a telephoto lens is hard to reduce. The
dilemma of reducing lens length or increasing the magnification and
maintaining the imaging quality cause the design of the optical
imaging lens to be hard.
SUMMARY OF THE INVENTION
[0008] The invention provides an optical imaging lens capable of
maintaining good optical performance under the condition of a
reduced lens depth.
[0009] An embodiment of the invention provides an optical imaging
lens including a front lens group and a rear lens group from an
object side to an image side in order along an optical axis. The
optical axis includes a first optical axis and a second optical
axis not coinciding with the first optical axis. The front lens
group includes a first lens element and a second lens element from
the object side to the image side in order along the first optical
axis. The rear lens group includes a third lens element and a
fourth lens element from the object side to the image side in order
along the second optical axis. The first lens element to the fourth
lens element each comprise an object-side surface facing the object
side and allowing imaging rays to pass through and an image-side
surface facing the image side and allowing the imaging rays to pass
through. The first lens element has positive refracting power, and
the second lens element has negative refracting power. At least one
of the object-side surface and the image-side surface of the third
lens element is an aspheric surface. At least one of the
object-side surface and the image-side surface of the fourth lens
element is an aspheric surface. A maximum distance between the
image-side surface of the first lens element and the object-side
surface of the second lens element in a direction parallel to the
first optical axis is less than 0.2 mm. The optical imaging lens
satisfies: 6.1.ltoreq.ImaH/(G12+T2), where hnaH is an image height
of the optical imaging lens, G12 is an air gap from the first lens
element to the second lens element on the first optical axis, and
T2 is a thickness of the second lens element on the first optical
axis.
[0010] An embodiment of the invention provides an optical imaging
lens including a first lens element, a second lens element, a third
lens element, and a fourth lens element from an object side to an
image side in order along an optical axis. The first lens element
to the fourth lens element each include an object-side surface
facing the object side and allowing imaging rays to pass through
and an image-side surface facing the image side and allowing the
imaging rays to pass through. The first lens element has positive
refracting power. The second lens element has negative refracting
power. At least one of the object-side surface and the image-side
surface of the third lens element is an aspheric surface. At least
one of the object-side surface and the image-side surface of the
fourth lens element is an aspheric surface. A maximum distance
between the image-side surface of the first lens element and the
object-side surface of the second lens element in a direction
parallel to the optical axis is less than 0.2 mm. The optical
imaging lens satisfies: 6.1.ltoreq.ImaH/(G12+T2); and
1.2.ltoreq.G23/EPD, where ImaH is an image height of the optical
imaging lens, G12 is an air gap from the first lens element to the
second lens element on the optical axis, T2 is a thickness of the
second lens element on the optical axis, G23 is an air gap from the
second lens element to the third lens element on the optical axis,
and EPD is a diameter of an entrance pupil of the optical imaging
lens.
[0011] Based on the above, the optical imaging lens of the
embodiments of the invention has the following beneficial effects:
via the conditional expression and the arrangement of the
object-side surface or the image-side surface of the lens elements,
under the condition of a reduced system length or lens depth, the
optical imaging lens still has the optical performance of being
capable of overcoming aberrations and provides good imaging
quality.
[0012] In order to make the aforementioned features and advantages
of the disclosure more comprehensible, embodiments accompanied with
figures are described in detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] 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.
[0014] FIG. 1 is a schematic describing the surface structure of a
lens element.
[0015] FIG. 2 is a schematic describing the surface concave and
convex structure and the ray focus of a lens element.
[0016] FIG. 3 is a schematic describing the surface structure of
the lens element of example 1.
[0017] FIG. 4 is a schematic describing the surface structure of
the lens element of example 2.
[0018] FIG. 5 is a schematic describing the surface structure of
the lens element of example 3.
[0019] FIG. 6 is a schematic of an optical imaging lens of the
first embodiment of the invention.
[0020] FIG. 7A to FIG. 7D are diagrams of the longitudinal
spherical aberration and various aberrations of the optical imaging
lens of the first embodiment.
[0021] FIG. 8 shows detailed optical data of the optical imaging
lens of the first embodiment of the invention.
[0022] FIG. 9 shows aspheric surface parameters of the optical
imaging lens of the first embodiment of the invention.
[0023] FIG. 10 is a schematic of an optical imaging lens of the
second embodiment of the invention.
[0024] FIG. 11A to FIG. 11D are diagrams of the longitudinal
spherical aberration and various aberrations of the optical imaging
lens of the second embodiment.
[0025] FIG. 12 shows detailed optical data of the optical imaging
lens of the second embodiment of the invention.
[0026] FIG. 13 shows aspheric surface parameters of the optical
imaging lens of the second embodiment of the invention.
[0027] FIG. 14 is a schematic of an optical imaging lens of the
third embodiment of the invention.
[0028] FIG. 15A to FIG. 15D are diagrams of the longitudinal
spherical aberration and various aberrations of the optical imaging
lens of the third embodiment.
[0029] FIG. 16 shows detailed optical data of the optical imaging
lens of the third embodiment of the invention.
[0030] FIG. 17 shows aspheric surface parameters of the optical
imaging lens of the third embodiment of the invention.
[0031] FIG. 18 is a schematic of an optical imaging lens of the
fourth embodiment of the invention.
[0032] FIG. 19A to FIG. 19D are diagrams of the longitudinal
spherical aberration and various aberrations of the optical imaging
lens of the fourth embodiment.
[0033] FIG. 20 shows detailed optical data of the optical imaging
lens of the fourth embodiment of the invention.
[0034] FIG. 21 shows aspheric surface parameters of the optical
imaging lens of the fourth embodiment of the invention.
[0035] FIG. 22 is a schematic of an optical imaging lens of the
fifth embodiment of the invention.
[0036] FIG. 23A to FIG. 23D are diagrams of the longitudinal
spherical aberration and various aberrations of the optical imaging
lens of the fifth embodiment.
[0037] FIG. 24 shows detailed optical data of the optical imaging
lens of the fifth embodiment of the invention.
[0038] FIG. 25 shows aspheric surface parameters of the optical
imaging lens of the fifth embodiment of the invention.
[0039] FIG. 26 is a schematic of an optical imaging lens of the
sixth embodiment of the invention.
[0040] FIG. 27A to FIG. 27D are diagrams of the longitudinal
spherical aberration and various aberrations of the optical imaging
lens of the sixth embodiment.
[0041] FIG. 28 shows detailed optical data of the optical imaging
lens of the sixth embodiment of the invention.
[0042] FIG. 29 shows aspheric surface parameters of the optical
imaging lens of the sixth embodiment of the invention.
[0043] FIG. 30 is a schematic of an optical imaging lens of the
seventh embodiment of the invention.
[0044] FIG. 31A to FIG. 31D are diagrams of the longitudinal
spherical aberration and various aberrations of the optical imaging
lens of the seventh embodiment.
[0045] FIG. 32 shows detailed optical data of the optical imaging
lens of the seventh embodiment of the invention.
[0046] FIG. 33 shows aspheric surface parameters of the optical
imaging lens of the seventh embodiment of the invention.
[0047] FIG. 34 is a schematic of an optical imaging lens of the
eighth embodiment of the invention.
[0048] FIG. 35A to FIG. 35D are diagrams of the longitudinal
spherical aberration and various aberrations of the optical imaging
lens of the eighth embodiment.
[0049] FIG. 36 shows detailed optical data of the optical imaging
lens of the eighth embodiment of the invention.
[0050] FIG. 37 shows aspheric surface parameters of the optical
imaging lens of the eighth embodiment of the invention.
[0051] FIG. 38 and FIG. 39 show the numeric values of various
important parameters and relationship formulas thereof of the
optical imaging lens elements of the first to eighth embodiments of
the invention.
DESCRIPTION OF THE EMBODIMENTS
[0052] 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.
[0053] 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.
[0054] 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.
[0055] 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 element
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.
[0056] 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.
[0057] 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.
[0058] 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).
[0059] 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.
[0060] FIG. 6 is a schematic of an optical imaging lens of the
first embodiment of the invention, and FIG. 7A to FIG. 7D are
diagrams of the longitudinal spherical aberration and various
aberrations of the optical imaging lens of the first embodiment.
Referring first to FIG. 6, the optical imaging lens 10 of the first
embodiment of the invention includes an aperture stop 2, a first
lens element 3, a second lens element 4, a reflector 8, a third
lens element 5, a fourth lens element 6 and a filter 9 from the
object side to the image side in order along an optical axis I of
optical the imaging lens 10. When rays emitted by an object to be
photographed enter the optical imaging lens 10 and pass through the
aperture stop 2, the first lens element 3, and the second lens
element 4, are reflected by the reflector 8, and pass through the
third lens element 5, the fourth lens element 6, and the filter 9
in sequence, an image is formed on an image plane 100. The filter 9
is, for instance, an infrared cut-off filter configured to block
infrared in rays emitted by the object. It should be added that,
the object side is a side facing the object to be photographed and
the image side is a side facing the image plane 100.
[0061] In this embodiment, the optical imaging lens 10 includes a
front lens group FG and a rear lens group RG from the object side
to the image side in order along the optical axis I. 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 this
embodiment, the optical axis I is bent by the reflective surface 81
of the reflector 8. The first optical axis I1 is the portion of the
optical axis I before bent by the reflector 8, and the second
optical axis I2 is the other portion of the optical axis I after
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. The front lens group
FG includes the first lens element 3 and the second lens element 4
from the object side to the image side in order along the first
optical axis I1. The rear lens group RG includes the third lens
element 5 and the fourth lens element 6 from the object side to the
image side in order along the second optical axis I2. In this
embodiment, the reflector 8 is a mirror. However, in other
embodiments, the reflector 8 may be a prism or any other
appropriate reflective element.
[0062] The first lens element 3, the second lens element 4, the
third lens element 5, the fourth lens 6, and the filter 9 all each
have an object-side surface 31, 41, 51, 61, 91 facing the object
side and allowing the imaging rays to pass through and an
image-side surface 32, 42, 52, 62, 92 facing the image side and
allowing the imaging rays to pass through.
[0063] In this embodiment, to meet the demand for a light product,
the first lens element 3 to the fourth lens element 6 all have
refracting power, and the first lens element 3, the second lens
element 4, the third lens element 5, and the fourth lens element 6
are all made of a plastic material, but the materials of the first
lens element 3 to the fourth lens element 6 are not limited
thereto.
[0064] The first lens element 3 has positive refracting power. The
object-side surface 31 of the first lens element 3 is a convex
surface and 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. The image-side surface 32 of the first lens
element 3 has a convex portion 321 in a vicinity of the optical
axis I and a concave portion 324 in a vicinity of the periphery of
the first lens element 3.
[0065] The second lens element 4 has negative refracting power. The
object-side surface 41 of the second lens element 4 has a concave
portion 412 in a vicinity of the optical axis I and a convex
portion 413 in a vicinity of a periphery of the second lens element
4. The image-side surface 42 of the second lens element 4 is a
concave surface and has a concave portion 422 in a vicinity of the
optical axis I and a concave portion 424 in a vicinity of a
periphery of the second lens element 4.
[0066] The third lens element 5 has negative refracting power. The
object-side surface 51 of the third lens element 5 has a convex
portion 511 in a vicinity of the optical axis I and a concave
portion 514 in a vicinity of a periphery of the third lens element
5. The image-side surface 52 of the third lens element 5 has a
concave portion 522 in a vicinity of the optical axis I and a
convex portion 523 in a vicinity of the periphery of the third lens
element 5.
[0067] The fourth lens element 6 has negative refracting power. The
object-side surface 61 of the fourth lens element 6 has a concave
portion 612 in a vicinity of the optical axis I and a concave
portion 614 in a vicinity of a periphery of the fourth lens element
6. The image-side surface 62 is a convex surface and has a convex
portion 621 in a vicinity of the optical axis I and a convex
portion 623 in a vicinity of the periphery of the fourth lens
element 6.
[0068] In addition, only the aforementioned lens elements have
refracting power, and the quantity of the lens elements having
refracting power of the optical imaging lens 10 is only four.
[0069] The other detailed optical data of the first embodiment is
as shown in FIG. 8, and in the first embodiment, the effective
focal length (EFL) of the optical imaging lens 10 is 10.036 mm, the
half field of view (HFOV) thereof is 14.046.degree., the f-number
(Fno) thereof is 2.800, the system length (TTL) thereof is 9.143
mm, the image height (ImaH) thereof is 2.517 mm, the focal length
(fFG) of the front lens group FG thereof is 8.405 mm, and the lens
depth (Depth) thereof is 6.043 mm. In particular, the system length
refers to the distance from the object-side surface 31 of the first
lens element 3 to the image plane 100 on the optical axis I. The
lens depth, Depth, refers to a distance in a direction of the first
optical axis I1 from a first position P1 of the object-side surface
31 of the first lens element 3 intersecting the first optical axis
I1 to a second position P2 of the optical imaging lens 10 farthest
away from the first position P1 in the direction of the first
optical axis II. The second position P2 may be located on the
bottom edge in the figure of the reflector 8, the third lens
element 5, the fourth lens element 6, the filter 9, or the image
plane 100 as long as this position is farthest away from the first
position P1 in the direction of the first optical axis I1. In this
embodiment, the second position P2 may be located on the bottom
edge in the figure of the image plane 100.
[0070] In this embodiment, the included angle between the normal of
the reflective surface 81 and the first optical axis I1 is
45.degree., and the included angle between the normal of the
reflective surface 81 and the second optical axis I2 is 45.degree..
The normal of the reflective surface 81, the first optical axis I1,
and the second optical axis I2 are coplanar, and the 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 larger than 90.degree..
[0071] Moreover, in the present embodiment, the eight surfaces of
the object-side surfaces 31, 41, 51, and 61 and the image-side
surfaces 32, 42, 52, and 62 of the first lens element 3, the second
lens element 4, the third lens element 5, and the fourth lens
element 6 are all aspheric surfaces, and the aspheric surfaces are
defined according to the following general formula:
Z ( Y ) = Y 2 R / ( 1 + 1 - ( 1 + K ) Y 2 R 2 ) + i = 1 n a 1
.times. Y i ( 1 ) ##EQU00001##
[0072] wherein:
[0073] Y: distance between a point on the aspheric surface curve
and the optical axis I;
[0074] Z: depth (perpendicular distance between the point on the
aspheric surface that is spaced by the distance Y from the optical
axis I and a tangent plane tangent to the vertex of the aspheric
surface on the optical axis I) of the aspheric surface;
[0075] R: radius of curvature of the lens element surface in a
vicinity of the optical axis I;
[0076] K: conic constant;
[0077] a.sub.i: i-th aspheric surface coefficient.
[0078] Each of the aspheric coefficients of the object-side
surfaces 31, 41, 51, and 61 and the image-side surfaces 32, 42, 52,
and 62 in general formula (1) is as shown in FIG. 9. In particular,
column number 31 in FIG. 9 represents the aspheric coefficient of
the object-side surface 31 of the first lens element 3, and the
other column fields are defined in a similar manner.
[0079] Moreover, the relationship between each of the important
parameters in the optical imaging lens 10 of the first embodiment
is as shown in FIG. 38.
[0080] wherein,
[0081] T1 is the thickness of the first lens element 3 on the
optical axis I, i.e., on the first optical axis I1;
[0082] T2 is the thickness of the second lens element 4 on the
optical axis I, i.e., on the first optical axis I1;
[0083] T3 is the thickness of the third lens element 5 on the
optical axis I, i.e., on the second optical axis I2;
[0084] T4 is the thickness of the fourth lens element 6 on the
optical axis I, i.e., on the second optical axis I2;
[0085] TF is the thickness of the filter 9 on the optical axis I,
i.e., on the second optical axis I2;
[0086] G12 is the 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 on the optical axis I, i.e. an air gap from the
first lens element 3 to the second lens element 4 on the first
optical axis I1;
[0087] G2C is the distance on the first optical axis from the
second lens element 4 to the intersection point IP of the first
optical axis I1 and the second optical axis I2;
[0088] GC3 is the distance on the second optical axis from the
intersection point IP of the first optical axis I1 and the second
optical axis I2 to the third lens element 5; G23 is the 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 on the optical
axis I, i.e. an air gap from the second lens element 4 to the third
lens element 5 on the optical axis I, and i.e. the sum of G2C and
GC3;
[0089] G34 is the 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 on the optical axis I, i.e. an air gap from the
third lens element 5 to the fourth lens element 6 on the second
optical axis I2;
[0090] G4F is the distance from the image-side surface 62 of the
fourth lens element 6 to the object-side surface 91 of the filter 9
on the optical axis I, i.e. an air gap from the fourth lens element
6 to the filter 9 on the second optical axis I2;
[0091] GFP is the distance from the image-side surface 92 of the
filter 9 to the image plane 100 on the optical axis I, i.e. an air
gap from the filter 9 to the image plane 100 on the second optical
axis I2;
[0092] AGG is the sum of three air gaps from the first lens element
3 to the fourth lens element 6 on the optical axis I, i.e., the sum
of G12, G23, and G34;
[0093] ALT is the sum of the thicknesses of the first lens element
3, the second lens element 4, the third lens element 5, and the
fourth lens element 6 on the optical axis I, i.e., the sum of T1,
T2, T3, and T4;
[0094] TTL is the distance from the object-side surface 31 of the
first lens element 3 to the image plane 100 on the optical axis I,
i.e. the distance on the first optical axis I1 from the object-side
surface 31 of the first lens element 3 to the intersection point IP
of the first optical axis I1 and the second optical axis I2 plus
the distance on the second optical axis I2 from the intersection
point IP to the image plane 100;
[0095] BFL is the distance from the image-side surface 62 of the
fourth lens element 6 to the image plane 100 on the optical axis I,
i.e., on the second optical axis I2;
[0096] EFL is the effective focal length of the optical imaging
lens 10;
[0097] EPD is a diameter of an entrance pupil of the optical
imaging lens 10;
[0098] ImaH is an image height of the optical imaging lens 10;
and
[0099] Depth is a distance in a direction of the first optical axis
I1 from a first position P1 of the object-side surface 31 of the
first lens element 3 intersecting the first optical axis I1 to a
second position P2 of the optical imaging lens 10 farthest away
from the first position P1 in the direction of the first optical
axis I1.
[0100] Moreover, the following are further defined:
[0101] f1 is the focal length of the first lens element 3;
[0102] f2 is the focal length of the second lens element 4;
[0103] f3 is the focal length of the third lens element 5;
[0104] f4 is the focal length of the fourth lens element 6;
[0105] fFG is the focal length of the front lens group FG;
[0106] n1 is the index of refraction of the first lens element
3;
[0107] n2 is the index of refraction of the second lens element
4;
[0108] n3 is the index of refraction of the third lens element
5;
[0109] n4 is the index of refraction of the fourth lens element
6;
[0110] v1 is the Abbe number of the first lens element 3, and the
Abbe number can also be referred to as the coefficient of
dispersion;
[0111] v2 is the Abbe number of the second lens element 4;
[0112] v3 is the Abbe number of the third lens element 5; and
[0113] v4 is the Abbe number of the fourth lens element 6.
[0114] Referring further to FIG. 7A to FIG. 7D, FIG. 7A describes
longitudinal spherical aberration of the first embodiment when the
pupil radius thereof is 1.8000 mm, FIG. 7B and FIG. 7C respectively
describe 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 describes the distortion aberration
on the image plane 100 of the first embodiment when the wavelengths
thereof are 650 nm, 555 nm, and 470 mm. 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, indicating the off-axis rays at different
heights of each wavelength are all concentrated in a vicinity of
the 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 the
range of .+-.40 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 relative close, indicating the
imaging positions of different wavelength rays are relatively
concentrated, and therefore the chromatic aberration is also
significantly improved.
[0115] In the two field curvature figures of FIG. 7B and FIG. 7C,
the focal length variation amount of three representative
wavelengths in the entire field of view is within .+-.35 microns,
indicating that the optical system of the first embodiment can
effectively eliminate aberrations. The distortion aberration figure
of FIG. 7D shows the distortion aberration of the first embodiment
is maintained within the range of .+-.0.41%, indicating the
distortion aberration of the first embodiment satisfies the imaging
quality requirements of the optical system, and as a result, in
comparison to the current optical lens, in the first embodiment,
under the condition that the lens depth is reduced to about 6.043
mm, good imaging quality can still be provided. Therefore, in the
first embodiment, under the condition of maintaining good optical
performance, the lens depth can be reduced and the effective focal
length of the optical imaging lens 10 can be increased to achieve a
telephoto effect.
[0116] FIG. 10 is a schematic of an optical imaging lens of the
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 lens 10 of the invention is 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, and 6 are somewhat different. Moreover, in
this embodiment, the object-side surface 61 of the fourth lens
element 6 has a concave portion 612 in a vicinity of the optical
axis I and a convex portion 613 in a vicinity of a periphery of the
fourth lens element 6. In addition, the image-side surface 62 of
the fourth lens element 6 has a concave portion 622 in a vicinity
of the optical axis I and a convex portion 623 in a vicinity of a
periphery of the fourth lens element 6. It should be mentioned here
that, to clearly show the figure, in FIG. 10, a portion of the
reference numerals of the same concave portion and convex portion
as the first embodiment is omitted.
[0117] The detailed optical data of the optical imaging lens 10 is
as shown in FIG. 12, and in the second embodiment, the EFL of the
optical imaging lens 10 is 10.025 mm, the HFOV thereof is
14.069.degree., the Fno thereof is 2.800, the TTL thereof is 9.285
mm, the ImaH thereof is 2.517 mm, the fFG thereof is 8.456 mm, and
the Depth thereof is 6.043 mm.
[0118] FIG. 13 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, and 61 and the image-side surfaces
32, 42, 52, and 62 of the second embodiment in general formula
(1).
[0119] Moreover, the relationship between each of the important
parameters in the optical imaging lens 10 of the second embodiment
is as shown in FIG. 38.
[0120] In the longitudinal spherical aberration figure of FIG. 11A
of the second embodiment in the condition that the pupil radius
thereof is 1.8000 mm, the imaging point deviation of off-axis rays
at different heights is controlled to be within the range of .+-.40
microns. In the two field curvature figures of FIG. 11B and FIG.
11C, the focal length variation amount of three representative
wavelengths in the entire field of view is within .+-.27 microns.
The distortion aberration figure of FIG. 11D shows that the
distortion aberration of the second embodiment is maintained within
the range of .+-.0.5%. Accordingly, in comparison to the current
optical lens, in the second embodiment, good imaging quality can
still be provided under the condition of the lens depth reduced to
about 6.043 mm.
[0121] It can be known from the above that, the advantages of the
second embodiment in comparison to the first embodiment are: the
longitudinal aberration of the second embodiment is less than that
of the first embodiment, and the field curvature of the second
embodiment is less than that of the first embodiment.
[0122] FIG. 14 is a schematic of an optical imaging lens of the
third embodiment of the invention, and FIG. 15A to FIG. 15D are
diagrams of the longitudinal spherical aberration and various
aberrations of the optical imaging lens of the third embodiment.
Referring first to FIG. 14, the third embodiment of the optical
imaging lens 10 of the invention is 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, and 6 are somewhat different. Moreover, in
this embodiment, the object-side surface 61 of the fourth lens
element 6 has a concave portion 612 in a vicinity of the optical
axis I and a convex portion 613 in a vicinity of a periphery of the
fourth lens element 6. The image-side surface 62 of the fourth lens
element 6 has a convex portion 621 in a vicinity of the optical
axis I and a concave portion 624 in a vicinity of a periphery of
the fourth lens element 6. It should be mentioned here that, to
clearly show the figure, in FIG. 14, a portion of reference
numerals of the same concave portion and convex portion as the
first embodiment is omitted.
[0123] The detailed optical data of the optical imaging lens 10 is
as shown in FIG. 16, and in the third embodiment, the EFL of the
optical imaging lens 10 is 10.079 mm, the HFOV thereof is
14.008.degree., the Fno thereof is 2.801, the TTL thereof is 9.434
mm, the ImaH thereof is 2.517 mm, the fFG thereof is 8.51 mm, and
the Depth thereof is 5.920 mm.
[0124] FIG. 17 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, and 61 and the image-side surfaces
32, 42, 52, and 62 of the third embodiment in general formula
(1).
[0125] Moreover, the relationship between each of the important
parameters in the optical imaging lens 10 of the third embodiment
is as shown in FIG. 38.
[0126] In the longitudinal spherical aberration figure of FIG. 15A
of the third embodiment in the condition that the pupil radius
thereof is 1.8000 mm, the imaging point deviation of off-axis rays
at different heights is controlled to be within the range of .+-.37
microns. In the two field curvature figures of FIG. 15B and FIG.
15C, the focal length variation amount of three representative
wavelengths in the entire field of view is within .+-.50 microns.
The distortion aberration figure of FIG. 15D shows that the
distortion aberration of the third embodiment is maintained within
the range of .+-.0.45%. Accordingly, in comparison to the current
optical lens, in the third embodiment, good imaging quality can
still be provided under the condition of the lens depth reduced to
about 5.920 mm.
[0127] It can be known from the above that, advantages of the third
embodiment in comparison to the first embodiment are: the lens
depth of the optical imaging lens 10 of the third embodiment is
smaller than that of the first embodiment; the HFOV of the third
embodiment is less than that of the first embodiment, which
improves the telephoto effect; the longitudinal spherical
aberration of the third embodiment is less than that of the first
embodiment; and the third embodiment is easier to manufacture than
the first embodiment since the thickness difference of the lens
elements between the vicinity of the optical axis I and the
vicinity of the periphery is less, and therefore the yield is
higher.
[0128] FIG. 18 is a schematic of an optical imaging lens of the
fourth embodiment of the invention, and FIG. 19A to FIG. 19D are
diagrams of the longitudinal spherical aberration and various
aberrations of the optical imaging lens of the fourth embodiment.
Referring first to FIG. 18, the fourth embodiment of the optical
imaging lens 10 of the invention is 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, and 6 are somewhat different. Moreover, in
this embodiment, the fourth lens element 6 has positive refracting
power. The object-side surface 61 of the fourth lens element 6 has
a concave portion 612 in a vicinity of the optical axis I and a
convex portion 613 in a vicinity of a periphery of the fourth lens
element 6. In addition, in this embodiment, the image-side surface
62 of the fourth lens element 6 has a convex portion 621 in a
vicinity of the optical axis I and a concave portion 624 in a
vicinity of a periphery of the fourth lens element 6. It should be
mentioned here that, to clearly show the figure, in FIG. 18, a
portion of reference numerals of the same concave portion and
convex portion as the first embodiment is omitted.
[0129] The detailed optical data of the optical imaging lens 10 is
as shown in FIG. 20, and in the fourth embodiment, the EFL of the
optical imaging lens 10 is 10.021 mm, the HFOV thereof is
14.044.degree., the Fno thereof is 2.800, the TTL thereof is 9.009
mm, the ImaH thereof is 2.517 mm, the fFG thereof is 8.405 mm, and
the Depth thereof is 5.772 mm.
[0130] FIG. 21 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, and 61 and the image-side surfaces
32, 42, 52, and 62 of the fourth embodiment in general formula
(1).
[0131] Moreover, the relationship between each of the important
parameters in the optical imaging lens 10 of the fourth embodiment
is as shown in FIG. 38.
[0132] In the longitudinal spherical aberration figure of FIG. 19A
of the fourth embodiment in the condition that the pupil radius
thereof is 1.8000 mm, the imaging point deviation of off-axis rays
at different heights is controlled to be within the range of +36
microns. In the two field curvature figures of FIG. 19B and FIG.
19C, the focal length variation amount of three representative
wavelengths in the entire field of view is within .+-.35 microns.
The distortion aberration figure of FIG. 19D shows that the
distortion aberration of the fourth embodiment is maintained within
the range of .+-.0.6%. Accordingly, in comparison to the current
optical lens, in the fourth embodiment, good imaging quality can
still be provided under the condition of the lens depth reduced to
about 5.772 mm.
[0133] It can be known from the above that, the advantages of the
fourth embodiment in comparison to the first embodiment are: the
lens depth of the optical imaging lens 10 of the fourth embodiment
is less than that of the first embodiment; the HFOV of the fourth
embodiment is less than that of the first embodiment, which
improves the telephoto effect; and the longitudinal spherical
aberration of the fourth embodiment is less than that of the first
embodiment.
[0134] FIG. 22 is a schematic of an optical imaging lens of the
fifth embodiment of the invention, and FIG. 23A to FIG. 23D are
diagrams of the longitudinal spherical aberration and various
aberrations of the optical imaging lens of the fifth embodiment.
Referring first to FIG. 22, the fifth embodiment of the optical
imaging lens 10 of the invention is 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, and 6 are somewhat different. Moreover, in
this embodiment, the fourth lens element 6 has positive refracting
power. The image-side surface 32 of the first lens element 3 is a
convex surface, and has a convex portion 321 in a vicinity of the
optical axis I and a convex portion 323 in a vicinity of the
periphery of the first lens element 3. The object-side surface 41
of the second lens element 4 is a concave surface, and has a
concave portion 412 in a vicinity of the optical axis I and a
concave portion 414 in a vicinity of a periphery of the second lens
element 4. The object-side surface 61 of the fourth lens element 6
is a convex surface, and has a convex portion 611 in a vicinity of
the optical axis I and a convex portion 613 in a vicinity of a
periphery of the fourth lens element 6. The image-side surface 62
of the fourth lens element 6 is a concave surface, and has a
concave portion 622 in a vicinity of the optical axis I and a
concave portion 624 in a vicinity of a periphery of the fourth lens
element 6. It should be mentioned here that, to clearly show the
figure, in FIG. 22, a portion of reference numerals of the same
concave portion and convex portion as the first embodiment is
omitted.
[0135] The detailed optical data of the optical imaging lens 10 is
as shown in FIG. 24, and in the fifth embodiment, the EFL of the
optical imaging lens 10 is 10.053 mm, the HFOV thereof is
14.013.degree., the Fno thereof is 2.653, the TTL thereof is 8.700
mm, the ImaH thereof is 2.517 mm, the fFG thereof is 8.405 mm, and
the Depth thereof is 5.891 mm.
[0136] FIG. 25 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, and 61 and the image-side surfaces
32, 42, 52, and 62 of the fifth embodiment in general formula
(1).
[0137] Moreover, the relationship between each of the important
parameters in the optical imaging lens 10 of the fifth embodiment
is as shown in FIG. 39.
[0138] In the longitudinal spherical aberration figure of FIG. 23A
of the fifth embodiment in the condition that the pupil radius
thereof is 1.9000 mm, the imaging point deviation of off-axis rays
at different heights is controlled to be within the range of .+-.16
microns. In the two field curvature figures of FIG. 23B and FIG.
23C, the focal length variation amount of three representative
wavelengths in the entire field of view is within .+-.20 microns.
The distortion aberration figure of FIG. 23D shows that the
distortion aberration of the fifth embodiment is maintained within
the range of +0.3%. Accordingly, in comparison to the current
optical lens, in the fifth embodiment, good imaging quality can
still be provided under the condition of the lens depth reduced to
about 5.891 mm.
[0139] It can be known from the above that, advantages of the fifth
embodiment in comparison to the first embodiment are: the lens
depth of the optical imaging lens 10 of the fifth embodiment is
smaller than that of the first embodiment; the f-number of the
fifth embodiment is less than that of the first embodiment; the
HFOV of the fifth embodiment is less than that of the first
embodiment, which improves the telephoto effect; the longitudinal
spherical aberration of the fifth embodiment is less than that of
the first embodiment; the field curvature of the fifth embodiment
is less than that of the first embodiment; and the distortion of
the fifth embodiment is less than that of the first embodiment.
[0140] FIG. 26 is a schematic of an optical imaging lens of the
sixth embodiment of the invention, and FIG. 27A to FIG. 27D are
diagrams of the longitudinal spherical aberration and various
aberrations of the optical imaging lens of the sixth embodiment.
Referring first to FIG. 26, the sixth embodiment of the optical
imaging lens 10 of the invention is 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, and 6 are somewhat different. Moreover, in
this embodiment, the object-side surface 61 of the fourth lens
element 6 is a convex surface and has a convex portion 611 in a
vicinity of the optical axis I and a convex portion 613 in a
vicinity of a periphery of the fourth lens element 6. In addition,
in this embodiment, the image-side surface 62 of the fourth lens
element 6 is a concave surface, and has a concave portion 622 in a
vicinity of the optical axis I and a concave portion 624 in a
vicinity of a periphery of the fourth lens element 6. It should be
mentioned here that, to clearly show the figure, in FIG. 26, a
portion of reference numerals of the same concave portion and
convex portion as the first embodiment is omitted.
[0141] The detailed optical data of the optical imaging lens 10 is
as shown in FIG. 28, and in the sixth embodiment, the EFL of the
optical imaging lens 10 is 9.372 mm, the HFOV thereof is
14.999.degree., the Fno thereof is 2.610, the TTL thereof is 8.770
mm, the ImaH thereof is 2.517 mm, the fFG thereof is 8.108 mm, and
Depth thereof is 5.902 mm.
[0142] FIG. 29 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, and 61 and the image-side surfaces
32, 42, 52, and 62 of the sixth embodiment in general formula
(1).
[0143] Moreover, the relationship between each of the important
parameters in the optical imaging lens 10 of the sixth embodiment
is as shown in FIG. 39.
[0144] In the longitudinal spherical aberration figure of FIG. 27A
of the sixth embodiment in the condition that the pupil radius
thereof is 1.8000 mm, the imaging point deviation of off-axis rays
at different heights is controlled to be within the range of .+-.70
microns. In the two field curvature figures of FIG. 27B and FIG.
27C, the focal length variation amount of three representative
wavelengths in the entire field of view is within .+-.60 microns.
The distortion aberration figure of FIG. 27D shows that the
distortion aberration of the sixth embodiment is maintained within
the range of .+-.0.6%. Accordingly, in comparison to the current
optical lens, in the sixth embodiment, good imaging quality can
still be provided under the condition of the lens depth reduced to
about 5.902 mm.
[0145] It can be known from the above that, advantages of the sixth
embodiment in comparison to the first embodiment are: the lens
depth of the sixth embodiment is less than that of the first
embodiment; and the f-number of the sixth embodiment is less than
that of the first embodiment.
[0146] FIG. 30 is a schematic of an optical imaging lens of the
seventh embodiment of the invention, and FIG. 31A to FIG. 31D are
diagrams of the longitudinal spherical aberration and various
aberrations of the optical imaging lens of the seventh embodiment.
Referring first to FIG. 30, the seventh embodiment of the optical
imaging lens 10 of the invention is 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, and 6 are somewhat different. Moreover, in
this embodiment, the fourth lens element 6 has positive refracting
power. The object-side surface 61 of the fourth lens element 6 has
a concave portion 612 in a vicinity of the optical axis I and a
convex portion 613 in a vicinity of a periphery of the fourth lens
element 6. In addition, in this embodiment, the image-side surface
62 of the fourth lens element 6 has a convex portion 621 in a
vicinity of the optical axis I and a concave portion 624 in a
vicinity of a periphery of the fourth lens element 6. It should be
mentioned here that, to clearly show the figure, in FIG. 30, a
portion of reference numerals of the same concave portion and
convex portion as the first embodiment is omitted.
[0147] The detailed optical data of the optical imaging lens 10 is
as shown in FIG. 32, and in the seventh embodiment, the EFL of the
optical imaging lens 10 is 9.385 mm, the HFOV thereof is
14.995.degree., the Fno thereof is 2.635, the TTL thereof is 9.490
mm, the ImaH thereof is 2.517 mm, the fFG thereof is 8.653 mm, and
the Depth thereof is 6.074 mm.
[0148] FIG. 33 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, and 61 and the image-side surfaces
32, 42, 52, and 62 of the seventh embodiment in general formula
(1).
[0149] Moreover, the relationship between each of the important
parameters in the optical imaging lens 10 of the seventh embodiment
is as shown in FIG. 39.
[0150] In the longitudinal spherical aberration figure of FIG. 31A
of the seventh embodiment in the condition that the pupil radius
thereof is 1.8000 mm, the imaging point deviation of off-axis rays
at different heights is controlled to be within the range of .+-.90
microns. In the two field curvature figures of FIG. 31B and FIG.
31C, the focal length variation amount of three representative
wavelengths in the entire field of view is within .+-.110 microns.
The distortion aberration figure of FIG. 31D shows that the
distortion aberration of the seventh embodiment is maintained
within the range of .+-.0.55%. Accordingly, in comparison to the
current optical lens, in the seventh embodiment, good imaging
quality can still be provided under the condition of the lens depth
reduced to about 6.074 mm.
[0151] It can be known from the above that, the advantages of the
seventh embodiment in comparison to the first embodiment are: the
f-number of the optical imaging lens 10 of the seventh embodiment
is less than that of the first embodiment, and the seventh
embodiment is easier to manufacture than the first embodiment since
the thickness difference of the lens elements between the vicinity
of the optical axis I and the vicinity of the periphery is less,
and therefore the yield is higher.
[0152] FIG. 34 is a schematic of an optical imaging lens of the
eighth embodiment of the invention, and FIG. 35A to FIG. 35D are
diagrams of the longitudinal spherical aberration and various
aberrations of the optical imaging lens of the eighth embodiment.
Referring first to FIG. 34, the eighth embodiment of the optical
imaging lens 10 of the invention is 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, and 6 are somewhat different. Moreover, in
this embodiment, the object-side surface 61 of the fourth lens
element 6 has a concave portion 612 in a vicinity of the optical
axis I and a convex portion 613 in a vicinity of a periphery of the
fourth lens element 6. It should be mentioned here that, to clearly
show the figure, in FIG. 34, a portion of reference numerals of the
same concave portion and convex portion as the first embodiment is
omitted.
[0153] The detailed optical data of the optical imaging lens 10 is
as shown in FIG. 36, and in the eighth embodiment, the EFL of the
optical imaging lens 10 is 10.047 mm, the HFOV thereof is
13.956.degree., the Fno thereof is 2.800, the TTL thereof is 9.458
mm, the ImaH thereof is 2.517 mm, the fFG thereof is 8.317 mm, and
the Depth thereof is 6.043 mm.
[0154] FIG. 37 shows each of the aspheric coefficients of the
object-side surfaces 31, 41, 51, and 61 and the image-side surfaces
32, 42, 52, and 62 of the eighth embodiment in general formula
(1).
[0155] Moreover, the relationship between each of the important
parameters in the optical imaging lens 10 of the eighth embodiment
is as shown in FIG. 39.
[0156] In the longitudinal spherical aberration figure of FIG. 35A
of the eighth embodiment in the condition that the pupil radius
thereof is 1.8000 mm, the imaging point deviation of off-axis rays
at different heights is controlled to be within the range of .+-.38
microns. In the two field curvature figures of FIG. 35B and FIG.
35C, the focal length variation amount of three representative
wavelengths in the entire field of view is within .+-.50 microns.
The distortion aberration figure of FIG. 35D shows that the
distortion aberration of the eighth embodiment is maintained within
the range of .+-.0.5%. Accordingly, in comparison to the current
optical lens, in the eighth embodiment, good imaging quality can
still be provided under the condition of the lens depth reduced to
about 6.043 mm.
[0157] It can be known from the above that, advantages of the
eighth embodiment in comparison to the first embodiment are: the
HFOV of the eighth embodiment is smaller than that of the first
embodiment, which improves the telephoto effect; the longitudinal
spherical aberration of the eighth embodiment is less than that of
the first embodiment; and the eighth embodiment is easier to
manufacture than the first embodiment since the thickness
difference of the lens elements between the vicinity of the optical
axis I and the vicinity of the periphery is less, and therefore the
yield is higher.
[0158] FIG. 38 and FIG. 39 shows tables of each optical parameter
of the eight embodiments. When the relationship formula between
each optical parameter in the optical imaging lens 10 of the
embodiments of the invention satisfies at least one of the
following condition formulas, the designer can design an optical
imaging lens having good optical performance and a reduced overall
length or lens depth and being technically applicable:
[0159] 1. The first lens element 3 has positive refracting power,
the image-side surface 32 of the first lens element 3 has a convex
portion 321 in the vicinity of the optical axis I, the second lens
element 4 has negative refracting power, the object-side surface 41
of the second lens element 4 has a concave portion 412 in the
vicinity of the optical axis I, the maximum distance between the
image-side surface 32 of the first lens element 3 and the
object-side surface 41 of the second lens element 4 in a direction
parallel to the optical axis I (e.g. the first optical axis I1) is
less than 0.2 mm, and the optical imaging lens 10 satisfies
18.ltoreq.v1-v2.ltoreq.50, which makes the first lens element 3 and
the second lens element 4 form a similar-cemented lens that may
reduce spherical aberration, lateral chromatic aberration, and
longitudinal chromatic aberration. The design of the
similar-cemented lens reduces the value of G12+T2. When the first
optical axis I1 is perpendicular to the second optical axis I2, the
lens depth is related to T1+G12+T2+G2C and ImaH. If the optical
imaging lens 10 satisfies 6.1.ltoreq.ImaH/(G12+T2), when the lens
depth is reduced, the image height is not too small and the size of
image is thus not affected, or G12+T2 is not too long. Therefore,
the embodiments of the invention both reduce the aberration and
have the unexpected result of reducing the lens depth. Preferably,
6.1.ltoreq.ImaH/(G12+T2).ltoreq.15, so that the image height is not
too large and the lens depth is thus not affected, or G12+T2 is not
too small and the lens production is not affected. When the first
optical axis I1 is perpendicular to the second optical axis I2, the
lens depth is less than or equal to 6.1 mm. If the included angle
between the first optical axis I1 and the second optical axis I2 is
less than 90.degree., the lens depth may be less than or equal to
5.5 mm.
[0160] 2. In order to divide the optical imaging lens 10 into the
front lens group FG and the rear lens group RG and add the
reflector 8 to bend the optical axis I, the air gap between the
second lens element 4 and the third lens element 5 may satisfy
1.2.ltoreq.G23/EPD, so that there is enough space between the
second lens element 4 and the third lens element 5 to dispose the
reflector 8 so as to reflect rays. Preferably,
1.2.ltoreq.G23/EPD.ltoreq.2.4, so that GC3 is not too large and the
volume of the optical imaging lens 10 is thus not affected.
Besides, the optical imaging lens 10 may further satisfies
1.ltoreq.EFL/fFG.ltoreq.2 and T1/T2.ltoreq.3.7, so that the focal
lengths of the first lens element 3 and the second lens element 4
are not too large, and the focal length of the front lens group FG
is not too short, which facilitate the disposition of the reflector
8.
[0161] 3. The optical imaging lens 10 may satisfy
HFOV.ltoreq.25.degree. and TTL/EFL.ltoreq.1.01, which facilitate
the design of telephoto magnification, and also prevent ImaH from
being too large, so that the lens depth is not affected.
[0162] 4. At least one of the object-side surface 51 and the
image-side surface 52 of the third lens element 5 has a transition
point, which facilitate correcting the main aberration due to the
first lens element 3 and the second lens element 4. The optical
imaging lens 10 may satisfy at least one of
G34/(G12+T2).ltoreq.4.3, G23/T2.ltoreq.20, AAG/T2.ltoreq.26,
EFL/T2.ltoreq.40, 1.ltoreq.T1/G34.ltoreq.32,
2.ltoreq.ALT/G34.ltoreq.31, 4.ltoreq.G23/G34.ltoreq.62,
0.44.ltoreq.T3/G34.ltoreq.6.4, and 0.75.ltoreq.T4/G34.ltoreq.11.8.
Preferably, the optical imaging lens 10 may satisfy at least one of
0.1.ltoreq.G34/(G12+T2).ltoreq.4.3, 7.2.ltoreq.G23/T2.ltoreq.20,
7.8.ltoreq.AAG/T2.ltoreq.26, and 16.ltoreq.EFL/T2.ltoreq.40, so
that the thicknesses of the lens elements and the air gaps among
the lens elements may be maintained to be appropriate values. As a
result, any parameter is prevented to be too large, and the
miniaturization of the whole optical imaging lens 10 is thus not
adversely affected. Alternatively, any parameter is prevented to be
too small, and the assembly is thus not affected, or the difficulty
in production is thus not increased.
[0163] However, based on the unpredictability of the optical system
design, under the designs of the embodiments of the invention, by
satisfying the above condition formulas, in the embodiments of the
invention, lens length can be reduced, usable aperture is
increased, field of view is increased, and imaging quality is
increased, or assembly yield is increased such that the drawbacks
of the prior art are reduced.
[0164] Based on the above, the optical imaging lens 10 of the
embodiments of the invention may also achieve the following
efficacies and advantages:
[0165] 1. The longitudinal spherical aberration, the field
curvature, and the distortion of each embodiment of the invention
all satisfy usage criteria. Moreover, the three representative
wavelengths of 650 nm, 555 nm, and 470 nm are all concentrated in a
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 at different heights of the
off-axis rays can all achieve control and have good spherical
aberration, aberration, and distortion control capability.
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, indicating 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.
[0166] 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. For example, it is optional to form an additional
convex portion on the object-side surface in the vicinity of the
optical axis of the first lens element. 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.
[0167] 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.
* * * * *